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PLOS0
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Control of arbovirus transmission remains focused on vector control through application of insecticides directly to the environment. However, these insecticide applications are often reactive interventions that can be poorly-targeted, inadequate for localized control during outbreaks, and opposed due to environmental and toxicity concerns. In this study, we developed endectocide-treated feed as a systemic endectocide for birds to target blood feeding Culex tarsalis, the primary West Nile virus (WNV) bridge vector in the western United States, and conducted preliminary tests on the effects of deploying this feed in the field. In lab tests, ivermectin (IVM) was the most effective endectocide tested against Cx. tarsalis and WNV-infection did not influence mosquito mortality from IVM. Chickens and wild Eurasian collared doves exhibited no signs of toxicity when fed solely on bird feed treated with concentrations up to 200 mg IVM/kg of diet, and significantly more Cx. tarsalis that blood fed on these birds died (greater than 80% mortality) compared to controls (less than 25% mortality). Mosquito mortality following blood feeding correlated with IVM serum concentrations at the time of blood feeding, which dropped rapidly after the withdrawal of treated feed. Preliminary field testing over one WNV season in Fort Collins, Colorado demonstrated that nearly all birds captured around treated bird feeders had detectable levels of IVM in their blood. However, entomological data showed that WNV transmission was non-significantly reduced around treated bird feeders. With further development, deployment of ivermectin-treated bird feed might be an effective, localized WNV transmission control tool.
Output:
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West Nile virus (WNV) is a mosquito-borne virus that causes significant disease and death every year in humans, domesticated animals, and wildlife. Control of WNV transmission is focused on controlling the mosquito vector through applications of insecticides directly to the environment. In this study, we evaluate a novel control strategy for WNV transmission by targeting the main mosquito bridge vector in the Great Plains region, Culex tarsalis, through its blood feeding behavior. Because Culex tarsalis favor taking blood meals from particular bird species, our strategy aims to target these bird species with endectocide-treated bird feed that will result in lethal blood meals for Cx. tarsalis. In this study, we developed a safe and effective formulation of ivermectin-treated diet that resulted in increased mortality for Cx. tarsalis blood fed on birds consuming this treated diet as compared to mosquitoes feeding on control birds. We also conducted a pilot field trial in Fort Collins, Colorado to test this strategy in a natural transmission cycle, which demonstrated promising results.
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PLOS1
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Ebola virus emerged in West Africa in December 2013. The high population mobility and poor public health infrastructure in this region led to the development of the largest Ebola virus disease (EVD) outbreak to date.
On September 26, 2014, China dispatched a Mobile Biosafety Level-3 Laboratory (MBSL-3 Lab) and a well-trained diagnostic team to Sierra Leone to assist in EVD diagnosis using quantitative real-time PCR, which allowed the diagnosis of suspected EVD cases in less than 4 hours from the time of sample receiving. This laboratory was composed of three container vehicles equipped with advanced ventilation system, communication system, electricity and gas supply system. We strictly applied multiple safety precautions to reduce exposure risks. Personnel, materials, water and air flow management were the key elements of the biosafety measures in the MBSL-3 Lab. Air samples were regularly collected from the MBSL-3 Lab, but no evidence of Ebola virus infectious aerosols was detected. Potentially contaminated objects were also tested by collecting swabs. On one occasion, a pipette tested positive for EVD. A total of 1,635 suspected EVD cases (824 positive [50.4%]) were tested from September 28 to November 11, 2014, and no member of the diagnostic team was infected with Ebola virus or other pathogens, including Lassa fever. The specimens tested included blood (69.2%) and oral swabs (30.8%) with positivity rates of 54.2% and 41.9%, respectively. The China mobile laboratory was thus instrumental in the EVD outbreak response by providing timely and reliable diagnostics.
The MBSL-3 Lab significantly contributed to establishing a suitable laboratory response capacity during the emergence of EVD in Sierra Leone.
Output:
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A Mobile Biosafety Level-3 Laboratory (MBSL-3 Lab) and a well-trained diagnostic team were dispatched to Sierra Leone to assist in Ebola virus disease (EVD) diagnosis when the largest outbreak of EVD to date emerged in West Africa in 2014. This setup allowed for the diagnosis of suspected EVD cases in less than 4 hours from the time of sample receiving. The laboratory was composed of three container vehicles and was equipped with advanced ventilation system, communication system, electricity and gas supply system. Multiple safety precautions were strictly applied to reduce exposure risks. A total of 1,635 suspected EVD cases were evaluated from September 28 to November 11, 2014, and none of the staff members was infected with Ebola virus or other pathogens. The China mobile laboratory was thus instrumental in the EVD outbreak response by providing timely and accurate diagnostics. Therefore, the MBSL-3 Lab played a significant role in establishing a suitable laboratory response capacity during the emergence of EVD in Sierra Leone.
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PLOS2
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Infection with HIV-1 perturbs homeostasis of human T cell subsets, leading to accelerated immunologic deterioration. While studying changes in CD4+ memory and naïve T cells during HIV-1 infection, we found that a subset of CD4+ effector memory T cells that are CCR7−CD45RO−CD45RA+ (referred to as TEMRA cells), was significantly increased in some HIV-infected individuals. This T cell subset displayed a differentiated phenotype and skewed Th1-type cytokine production. Despite expressing high levels of CCR5, TEMRA cells were strikingly resistant to infection with CCR5 (R5)–tropic HIV-1, but remained highly susceptible to CXCR4 (X4)–tropic HIV-1. The resistance of TEMRA cells to R5-tropic viruses was determined to be post-entry of the virus and prior to early viral reverse transcription, suggesting a block at the uncoating stage. Remarkably, in a subset of the HIV-infected individuals, the relatively high proportion of TEMRA cells within effector T cells strongly correlated with higher CD4+ T cell numbers. These data provide compelling evidence for selection of an HIV-1–resistant CD4+ T cell population during the course of HIV-1 infection. Determining the host factors within TEMRA cells that restrict R5-tropic viruses and endow HIV-1–specific CD4+ T cells with this ability may result in novel therapeutic strategies against HIV-1 infection.
Output:
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HIV-1 infection profoundly perturbs the immune system and is characterized by depletion of CD4+ T cells and chronic immune activation, which lead to AIDS. Although HIV-1 targets CD4+ T cells, it also requires a second receptor in order to infect the target cells. The majority of HIV-1 strains that are transmitted use a cell surface molecule called CCR5, which is expressed on a portion of T cells. In this manuscript we identify a subset of human CD4+ T cells, which we termed TEMRA cells, that express CCR5 but still remain resistant to infection. We show that HIV-1 infection is blocked in TEMRA cells after entry of the virus, but before it has a chance to integrate into the cellular genome. TEMRA cells are present at low frequency in HIV-1 uninfected individuals but greatly increase in some HIV-infected individuals, which correlates with higher CD4+ T cell numbers. These findings provide the basis for future studies to understand the role of TEMRA cells during HIV-1 infection and identify the host factors that could restrict the virus. This knowledge may be used to endow susceptible T cells with the ability to resist infection and result in novel vaccine or therapeutic strategies against HIV-1 infection.
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PLOS3
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The guanylate-binding proteins (GBPs) belong to the dynamin superfamily of GTPases and function in cell-autonomous defense against intracellular pathogens. IpaH9.8, an E3 ligase from the pathogenic bacterium Shigella flexneri, ubiquitinates a subset of GBPs and leads to their proteasomal degradation. Here we report the structure of a C-terminally truncated GBP1 in complex with the IpaH9.8 Leucine-rich repeat (LRR) domain. IpaH9.8LRR engages the GTPase domain of GBP1, and differences in the Switch II and α3 helix regions render some GBPs such as GBP3 and GBP7 resistant to IpaH9.8. Comparisons with other IpaH structures uncover interaction hot spots in their LRR domains. The C-terminal region of GBP1 undergoes a large rotation compared to previously determined structures. We further show that the C-terminal farnesylation modification also plays a role in regulating GBP1 conformation. Our results suggest a general mechanism by which the IpaH proteins target their cellular substrates and shed light on the structural dynamics of the GBPs.
Output:
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Shigella flexneri is a Gram-negative bacteria that causes diarrhea in humans and leads to a million deaths every year. Once inside the cell, S. flexneri injects the host cell cytoplasm with effector proteins to suppress host defense. The guanylate-binding proteins (GBPs) have potent antimicrobial functions against a number of pathogens including S. flexneri. For successful infection, S. flexneri relies on an effector protein known as IpaH9.8, a unique ubiquitin E3 ligase to target a subset of GBPs for proteasomal degradation. How these GBPs are specifically recognized by IpaH9.8 was unclear. Here, using a combination of structural and biochemical approaches, we reveal the molecular basis of GBP-IpaH9.8 interaction, and show that subtle differences in the seven human GBPs can significantly impact the targeting specificity of IpaH9.8. We also show that the GBPs have considerable structural flexibility, which is likely important for their function. Our results provide further insights into S. flexneri pathogenesis, and laid the groundwork for future biophysical and biochemical studies to investigate the functional mechanism of GBPs.
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PLOS4
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Identification of cellular receptors and characterization of viral tropism in animal models have vastly improved our understanding of morbillivirus pathogenesis. However, specific aspects of viral entry, dissemination and transmission remain difficult to recapitulate in animal models. Here, we used three virologically identical but phenotypically distinct recombinant (r) canine distemper viruses (CDV) expressing different fluorescent reporter proteins for in vivo competition and airborne transmission studies in ferrets (Mustela putorius furo). Six donor ferrets simultaneously received three rCDVs expressing green, red or blue fluorescent proteins via conjunctival (ocular, Oc), intra-nasal (IN) or intra-tracheal (IT) inoculation. Two days post-inoculation sentinel ferrets were placed in physically separated adjacent cages to assess airborne transmission. All donor ferrets developed lymphopenia, fever and lethargy, showed progressively increasing systemic viral loads and were euthanized 14 to 16 days post-inoculation. Systemic replication of virus inoculated via the Oc, IN and IT routes was detected in 2/6, 5/6 and 6/6 ferrets, respectively. In five donor ferrets the IT delivered virus dominated, although replication of two or three different viruses was detected in 5/6 animals. Single lymphocytes expressing multiple fluorescent proteins were abundant in peripheral blood and lymphoid tissues, demonstrating the occurrence of double and triple virus infections. Transmission occurred efficiently and all recipient ferrets showed evidence of infection between 18 and 22 days post-inoculation of the donor ferrets. In all cases, airborne transmission resulted in replication of a single-colored virus, which was the dominant virus in the donor ferret. This study demonstrates that morbilliviruses can use multiple entry routes in parallel, and co-infection of cells during viral dissemination in the host is common. Airborne transmission was efficient, although transmission of viruses expressing a single color suggested a bottleneck event. The identity of the transmitted virus was not determined by the site of inoculation but by the viral dominance during dissemination.
Output:
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Canine distemper virus (CDV) infection of ferrets is a tractable animal model for measles. Ferrets are highly susceptible to CDV, and inoculation with a low dose leads to lethal disease. We performed in vivo competition experiments to study virus entry, dissemination and transmission. Ferrets were simultaneously inoculated with CDV via the conjunctival, intra-nasal and intra-tracheal routes. The viruses were identical except for the fluorescent reporter protein encoded by the viral genome. By detecting cells expressing the different fluorescent reporter proteins at various sites in the host, we determined that CDV can enter the host in parallel at multiple sites. Virus spread in the ferret occurred via infected lymphocytes, which often turned out to be double- or triple-infected. Sentinel ferrets, placed in physically separated adjacent cages, became infected by airborne transmission. Transmission of the dominant single color despite replication of multicolor viruses in the upper respiratory tract suggested a bottleneck event.
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PLOS5
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Seminal fluid proteins affect fertility at multiple stages in reproduction. In many species, a male's ejaculate coagulates to form a copulatory plug. Although taxonomically widespread, the molecular details of plug formation remain poorly understood, limiting our ability to manipulate the structure and understand its role in reproduction. Here I show that male mice knockouts for transglutaminase IV (Tgm4) fail to form a copulatory plug, demonstrating that this gene is necessary for plug formation and lending a powerful new genetic tool to begin characterizing plug function. Tgm4 knockout males show normal sperm count, sperm motility, and reproductive morphology. However, very little of their ejaculate migrates into the female's reproductive tract, suggesting the plug prevents ejaculate leakage. Poor ejaculate migration leads to a reduction in the proportion of oocytes fertilized. However, Tgm4 knockout males fertilized between 3–11 oocytes, which should be adequate for a normal litter. Nevertheless, females mated to Tgm4 knockout males for approximately 14 days were significantly less likely to give birth to a litter compared to females mated to wild-type males. Therefore, it appears that the plug also affects post-fertilization events such as implantation and/or gestation. This study shows that a gene influencing the viscosity of seminal fluid has a major influence on male fertility.
Output:
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Male reproductive fitness is strongly affected by seminal fluid. In many animals, the male's ejaculate coagulates in the female's reproductive tract to form a structure known as the copulatory plug. Here, I show that male mice without a functional copy of the gene transglutaminase IV cannot form a plug and suffer severe fertility defects. In spite of normal reproductive morphology, less of the ejaculate migrates through the female's reproductive tract and Tgm4 knockout males sire significantly fewer litters than wild type. This study demonstrates that the copulatory plug and/or Tgm4 itself is necessary for normal fertility.
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PLOS6
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Determining the duration of protective immunity requires quantifying the magnitude and rate of loss of antibodies to different virus and vaccine antigens. A key complication is heterogeneity in both the magnitude and decay rate of responses of different individuals to a given vaccine, as well as of a given individual to different vaccines. We analyzed longitudinal data on antibody titers in 45 individuals to characterize the extent of this heterogeneity and used models to determine how it affected the longevity of protective immunity to measles, rubella, vaccinia, tetanus, and diphtheria. Our analysis showed that the magnitude of responses in different individuals varied between 12- and 200-fold (95% coverage) depending on the antigen. Heterogeneity in the magnitude and decay rate contribute comparably to variation in the longevity of protective immunity between different individuals. We found that some individuals have, on average, slightly longer-lasting memory than others—on average, they have higher antibody levels with slower decay rates. We identified different patterns for the loss of protective levels of antibodies to different vaccine and virus antigens. Specifically, we found that for the first 25 to 50 years, virtually all individuals have protective antibody titers against diphtheria and tetanus, respectively, but about 10% of the population subsequently lose protective immunity per decade. In contrast, at the outset, not all individuals had protective titers against measles, rubella, and vaccinia. However, these antibody titers wane much more slowly, with a loss of protective immunity in only 1% to 3% of the population per decade. Our results highlight the importance of long-term longitudinal studies for estimating the duration of protective immunity and suggest both how vaccines might be improved and how boosting schedules might be reevaluated.
Output:
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Immunological memory, mediated by antibodies, is a hallmark of immunity. A key problem for determining the longevity of protective immunity is heterogeneity in the responses of different individuals. We characterize the extent of this heterogeneity and determine how it affects the longevity of protection. We found that some individuals have higher antibody titers and these same individuals tend to have slower decay rates than others. We also found substantial heterogeneity in both the magnitude and decay rate of responses. Furthermore, differences in these two factors contribute comparably to the variation in antibody titers between different individuals over their lifetime. We then use statistical models to determine how variation in the magnitude and decay rate affect how protective immunity is lost at the population level to different virus and vaccine antigens. We identified different patterns for the loss of protective immunity elicited by protein immunization (tetanus and diphtheria) versus replicating viruses (measles, rubella, and vaccinia). While our results agree with the conventional view that antibodies elicited by protein immunization decay faster than those elicited by replicating viruses, we found that this is compensated for by the higher magnitude of responses (relative to the level for protection) for tetanus and diphtheria. Indeed, for the first 4 decades, a higher fraction of vaccinated individuals have protective immunity to tetanus and diphtheria than to measles, rubella, and vaccinia.
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PLOS7
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The Down syndrome cell adhesion molecule, also known as Dscam, is a member of the immunoglobulin super family. Dscam plays an essential function in neuronal wiring and appears to be involved in innate immune reactions in insects. The deduced amino acid sequence of Dscam in the crustacean Pacifastacus leniusculus (PlDscam), encodes 9(Ig)-4(FNIII)-(Ig)-2(FNIII)-TM and it has variable regions in the N-terminal half of Ig2 and Ig3 and the complete Ig7 and in the transmembrane domain. The cytoplasmic tail can generate multiple isoforms. PlDscam can generate more than 22,000 different unique isoforms. Bacteria and LPS injection enhanced the expression of PlDscam, but no response in expression occurred after a white spot syndrome virus (WSSV) infection or injection with peptidoglycans. Furthermore, PlDscam silencing did not have any effect on the replication of the WSSV. Bacterial specific isoforms of PlDscam were shown to have a specific binding property to each tested bacteria, E. coli or S. aureus. The bacteria specific isoforms of PlDscam were shown to be associated with bacterial clearance and phagocytosis in crayfish.
Output:
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Invertebrate animals lack an adaptive immune system and have no antibodies. Vertebrate antibodies belong to the immunoglobulin super family of proteins, and one other member of this large family is the Down syndrome cell adhesion molecule or Dscam. Of specific interest is that Dscam proteins in invertebrates show a great diversity of isoforms, and its gene structure in Drosophila melanogaster and other insect species allow for more than 30,000 different isoforms. Dscam proteins are important for the interaction between neurons in insects, but recently a role for this hypervariable protein in immune defense has been shown. Here, we show that Dscam proteins with similar highly variable structures are present in a crustacean, the freshwater crayfish Pacifastacus leniusculus. We also found that specific isoforms could be induced in the animal after injection of different bacteria. The Dscam isoforms induced by Escherichia coli were found to cluster together in a phylogenetic analysis. Furthermore we produced recombinant proteins of the different isoforms that were induced by E. coli and Staphylococcus aureus and we could demonstrate that these proteins can bind specifically to their corresponding bacteria. The bacteria specific isoforms of Dscam were also shown to be associated with bacterial clearance and phagocytosis in crayfish. Our study therefore provides new insights into the function of invertebrate Dscams in immunity.
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PLOS8
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Vaginal HIV transmission accounts for the majority of new infections worldwide. Currently, multiple efforts to prevent HIV transmission are based on pre-exposure prophylaxis with various antiretroviral drugs. Here, we describe two novel nanoformulations of the reverse transcriptase inhibitor rilpivirine for pericoital and coitus-independent HIV prevention. Topically applied rilpivirine, encapsulated in PLGA nanoparticles, was delivered in a thermosensitive gel, which becomes solid at body temperature. PLGA nanoparticles with encapsulated rilpivirine coated the reproductive tract and offered significant protection to BLT humanized mice from a vaginal high-dose HIV-1 challenge. A different nanosuspension of crystalline rilpivirine (RPV LA), administered intramuscularly, protected BLT mice from a single vaginal high-dose HIV-1 challenge one week after drug administration. Using transmitted/founder viruses, which were previously shown to establish de novo infection in humans, we demonstrated that RPV LA offers significant protection from two consecutive high-dose HIV-1 challenges one and four weeks after drug administration. In this experiment, we also showed that, in certain cases, even in the presence of drug, HIV infection could occur without overt or detectable systemic replication until levels of drug were reduced. We also showed that infection in the presence of drug can result in acquisition of multiple viruses after subsequent exposures. These observations have important implications for the implementation of long-acting antiretroviral formulations for HIV prevention. They provide first evidence that occult infections can occur, despite the presence of sustained levels of antiretroviral drugs. Together, our results demonstrate that topically- or systemically administered rilpivirine offers significant coitus-dependent or coitus-independent protection from HIV infection.
Output:
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When taken consistently, PrEP has been shown to reduce the risk of HIV infection by up to 92% in people who are at high risk. However, PrEP is much less effective if it is not taken consistently. To improve adherence to the drug regimen, several new drug delivery systems, that include novel gel formulations and long-acting delivery systems, are being evaluated. In this manuscript, we used BLT humanized mice, an in vivo model of vaginal HIV transmission, to evaluate two novel delivery systems for HIV prevention. In the first approach, we combined the highly efficient encapsulation of antiretroviral drugs into nanoparticles with a thermosensitive gel that remains liquid at room temperature and solidifies at body temperature. Our results showed that this delivery system provided significant protection from HIV vaginal infection. In a second approach, we evaluated a long-acting nanoparticle formulation for coitus-independent protection from HIV acquisition. Our results showed that a single injection of the long-acting antiviral drug also resulted in reduced HIV infection. However, protection was not complete and transmission was concealed by a significant delay in the onset of plasma viremia that could result in superinfection by two different viruses administered up to four weeks apart.
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PLOS9
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The CsrRS (or CovRS) two component system controls expression of up to 15% of the genome of group A Streptococcus (GAS). While some studies have suggested that the sensor histidine kinase CsrS responds to membrane perturbations as a result of various environmental stresses, other data have implicated the human antimicrobial peptide LL-37 and extracellular Mg2+ as specific signals. We now report that Mg2+ and LL-37 have opposite effects on expression of multiple genes that are activated or repressed by the transcriptional regulator CsrR. Using a GAS isolate representative of the recently emerged and widely disseminated M1T1 clone implicated in severe invasive disease, we found marked up-regulation by CsrRS of multiple virulence factors including pyrogenic exotoxin A, DNase Sda1, streptolysin O, and the hyaluronic acid capsular polysaccharide, among others. Topology and surface protein labeling studies indicated that CsrS is associated with the bacterial cell membrane and has a surface-exposed extracellular domain accessible to environmental ligands. Replacement of a cluster of three acidic amino acids with uncharged residues in the extracellular domain of CsrS abrogated LL-37 signaling and conferred a hyporesponsive phenotype consistent with tonic activation of CsrS autokinase activity, an effect that could be overridden by mutation of the CsrS active site histidine. Both loss- and gain-of-function mutations of a conserved site in the receiver domain of CsrR established an essential role for lysine 102 in CsrS-to-CsrR signal transduction. These results provide strong evidence that Mg2+ and LL-37 are specific signals that function by altering CsrS autokinase activity and downstream phosphotransfer to CsrR to modulate its activity as a transcriptional regulator. The representation of multiple antiphagocytic and cytotoxic factors in the CsrRS regulon together with results of in vitro phagocytic killing assays support the hypothesis that CsrRS mediates conversion of GAS from a colonizing to an invasive phenotype in response to signaling by host LL-37.
Output:
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Group A Streptococcus (S. pyogenes or GAS) is exclusively a human pathogen that can inhabit the human throat as a harmless commensal, cause localized, self-limited infection in the form of pharyngitis or strep throat, or invade local tissues or the bloodstream to produce life-threatening disease states such as necrotizing fasciitis or streptococcal toxic shock. We present evidence that the GAS CsrRS (or CovRS) two component system governs the transition from a colonizing to an invasive phenotype by transducing a specific signal from the antimicrobial peptide LL-37 that is secreted as part of the human innate immune response to GAS infection. We show that LL-37 signaling requires specific domains of both the CsrS sensor kinase and the CsrR response regulator, and that signaling results in a coordinated and marked increase in expression of multiple bacterial factors that confer resistance to phagocytic killing, a hallmark of GAS virulence.
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PLOS10
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: North East Europe harbors a high diversity of cultures and languages, suggesting a complex genetic history. Archaeological, anthropological, and genetic research has revealed a series of influences from Western and Eastern Eurasia in the past. While genetic data from modern-day populations is commonly used to make inferences about their origins and past migrations, ancient DNA provides a powerful test of such hypotheses by giving a snapshot of the past genetic diversity. In order to better understand the dynamics that have shaped the gene pool of North East Europeans, we generated and analyzed 34 mitochondrial genotypes from the skeletal remains of three archaeological sites in northwest Russia. These sites were dated to the Mesolithic and the Early Metal Age (7,500 and 3,500 uncalibrated years Before Present). We applied a suite of population genetic analyses (principal component analysis, genetic distance mapping, haplotype sharing analyses) and compared past demographic models through coalescent simulations using Bayesian Serial SimCoal and Approximate Bayesian Computation. Comparisons of genetic data from ancient and modern-day populations revealed significant changes in the mitochondrial makeup of North East Europeans through time. Mesolithic foragers showed high frequencies and diversity of haplogroups U (U2e, U4, U5a), a pattern observed previously in European hunter-gatherers from Iberia to Scandinavia. In contrast, the presence of mitochondrial DNA haplogroups C, D, and Z in Early Metal Age individuals suggested discontinuity with Mesolithic hunter-gatherers and genetic influx from central/eastern Siberia. We identified remarkable genetic dissimilarities between prehistoric and modern-day North East Europeans/Saami, which suggests an important role of post-Mesolithic migrations from Western Europe and subsequent population replacement/extinctions. This work demonstrates how ancient DNA can improve our understanding of human population movements across Eurasia. It contributes to the description of the spatio-temporal distribution of mitochondrial diversity and will be of significance for future reconstructions of the history of Europeans.
Output:
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The history of human populations can be retraced by studying the archaeological and anthropological record, but also by examining the current distribution of genetic markers, such as the maternally inherited mitochondrial DNA. Ancient DNA research allows the retrieval of DNA from ancient skeletal remains and contributes to the reconstruction of the human population history through the comparison of ancient and present-day genetic data. Here, we analysed the mitochondrial DNA of prehistoric remains from archaeological sites dated to 7,500 and 3,500 years Before Present. These sites are located in North East Europe, a region that displays a significant cultural and linguistic diversity today but for which no ancient human DNA was available before. We show that prehistoric hunter-gatherers of North East Europe were genetically similar to other European foragers. We also detected a prehistoric genetic input from Siberia, followed by migrations from Western Europe into North East Europe. Our research contributes to the understanding of the origins and past dynamics of human population in Europe.
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PLOS11
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Highly pathogenic H5N1 influenza A viruses have spread across Asia, Europe, and Africa. More than 500 cases of H5N1 virus infection in humans, with a high lethality rate, have been reported. To understand the molecular basis for the high virulence of H5N1 viruses in mammals, we tested the virulence in ferrets of several H5N1 viruses isolated from humans and found A/Vietnam/UT3062/04 (UT3062) to be the most virulent and A/Vietnam/UT3028/03 (UT3028) to be avirulent in this animal model. We then generated a series of reassortant viruses between the two viruses and assessed their virulence in ferrets. All of the viruses that possessed both the UT3062 hemagglutinin (HA) and nonstructural protein (NS) genes were highly virulent. By contrast, all those possessing the UT3028 HA or NS genes were attenuated in ferrets. These results demonstrate that the HA and NS genes are responsible for the difference in virulence in ferrets between the two viruses. Amino acid differences were identified at position 134 of HA, at positions 200 and 205 of NS1, and at positions 47 and 51 of NS2. We found that the residue at position 134 of HA alters the receptor-binding property of the virus, as measured by viral elution from erythrocytes. Further, both of the residues at positions 200 and 205 of NS1 contributed to enhanced type I interferon (IFN) antagonistic activity. These findings further our understanding of the determinants of pathogenicity of H5N1 viruses in mammals.
Output:
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Highly pathogenic H5N1 influenza A viruses have caused more than 500 human infections with approximately 60% lethality in 15 countries and continue to pose a pandemic threat. The recent worldwide spread of pandemic H1N1 influenza A viruses raises the concern of reassortment between the H5N1 viruses and other influenza viruses. However, the molecular determinants for high virulence of the H5N1 viruses in mammals are not fully understood. We, therefore, investigated their virulence in a ferret model, which is a widely accepted animal model for assessing human influenza virus replication. We identified an amino acid in hemagglutinin and four amino acids in nonstructural proteins that are associated with high virulence of a human H5N1 virus, A/Vietnam/UT3062/04. We also found that the amino acid in hemagglutinin changes its receptor-binding property and the amino acids in nonstructural protein 1 affect its interferon antagonistic ability. These findings provide insight into the pathogenesis of H5N1 viruses in mammals.
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PLOS12
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Plant microRNAs (miRNA) guide cleavage of target mRNAs by DICER-like proteins, thereby reducing mRNA abundance. Native precursor miRNAs can be redesigned to target RNAs of interest, and one application of such artificial microRNA (amiRNA) technology is to generate plants resistant to pathogenic viruses. Transgenic Arabidopsis plants expressing amiRNAs designed to target the genome of two unrelated viruses were resistant, in a highly specific manner, to the appropriate virus. Here, we pursued two different goals. First, we confirmed that the 21-nt target site of viral RNAs is both necessary and sufficient for resistance. Second, we studied the evolutionary stability of amiRNA-mediated resistance against a genetically plastic RNA virus, TuMV. To dissociate selective pressures acting upon protein function from those acting at the RNA level, we constructed a chimeric TuMV harboring a 21-nt, amiRNA target site in a non-essential region. In the first set of experiments designed to assess the likelihood of resistance breakdown, we explored the effect of single nucleotide mutation within the target 21-nt on the ability of mutant viruses to successfully infect amiRNA-expressing plants. We found non-equivalency of the target nucleotides, which can be divided into three categories depending on their impact in virus pathogenicity. In the second set of experiments, we investigated the evolution of the virus mutants in amiRNA-expressing plants. The most common outcome was the deletion of the target. However, when the 21-nt target was retained, viruses accumulated additional substitutions on it, further reducing the binding/cleavage ability of the amiRNA. The pattern of substitutions within the viral target was largely dominated by G to A and C to U transitions.
Output:
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RNA viruses are well-known for their tremendous capacity to evolve, a characteristic that threatens the development of effective antiviral strategies. A new antiviral strategy was recently proposed to control plant RNA viruses that relied on the expression in plants of artificial microRNAs (amiRNAs) targeting short sequences of 21-nt in the viral genome. Here, we have evaluated the likelihood that changes in the 21-nt target sequence would result in resistance breakdown. We found that changes at different sites in the target had different consequences on the ability of the virus to evade amiRNA surveillance. Then, we evolved viruses with a single substitution within the target under the selective pressure imposed by amiRNAs but without any selective pressure at the protein level. We found extra mutations accumulated in the target that further reduced base pairing with the amiRNA. These results showed that when allowed to replicate, RNA viruses would readily generate genetic variability that would facilitate evasion from the engineered miRNA-mediated virus resistance.
|
PLOS13
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Iron is essential for photosynthesis and is often a limiting nutrient for plant productivity. Plants respond to conditions of iron deficiency by increasing transcript abundance of key genes involved in iron homeostasis, but only a few regulators of these genes have been identified. Using genome-wide expression analysis, we searched for transcription factors that are induced within 24 hours after transferring plants to iron-deficient growth conditions. Out of nearly 100 transcription factors shown to be up-regulated, we identified MYB10 and MYB72 as the most highly induced transcription factors. Here, we show that MYB10 and MYB72 are functionally redundant and are required for plant survival in alkaline soil where iron availability is greatly restricted. myb10myb72 double mutants fail to induce transcript accumulation of the nicotianamine synthase gene NAS4. Both myb10myb72 mutants and nas4-1 mutants have reduced iron concentrations, chlorophyll levels, and shoot mass under iron-limiting conditions, indicating that these genes are essential for proper plant growth. The double myb10myb72 mutant also showed nickel and zinc sensitivity, similar to the nas4 mutant. Ectopic expression of NAS4 rescues myb10myb72 plants, suggesting that loss of NAS4 is the primary defect in these plants and emphasizes the importance of nicotianamine, an iron chelator, in iron homeostasis. Overall, our results provide evidence that MYB10 and MYB72 act early in the iron-deficiency regulatory cascade to drive gene expression of NAS4 and are essential for plant survival under iron deficiency.
Output:
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Iron deficiency is the most common human nutritional disorder, afflicting more than three billion people worldwide. Most of these people rely on plants for their dietary iron. Iron is also one of the three nutrients that most commonly limit plant growth. Despite progress in tracing how Fe moves throughout the plant, we still do not fully understand how plants sense and respond to Fe availability. Here, we report on two apparently redundant MYB transcription factors that are acting to control one gene that has a major impact on the ability of plants to grow in alkaline soil where iron availability is greatly restricted. In the absence of these transcription factors, plants are unable to survive on this soil. As 1/3 of the world's soils are alkaline, understanding how plants cope may enable the growth of crops on soils currently not suitable for agricultural production. These two transcription factors also extend the iron deficiency network and this work provides insight into the tight control plants exert over iron uptake and distribution.
|
PLOS14
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Chikungunya virus (CHIKV) is a re-emerging, pathogenic alphavirus that is transmitted to humans by Aedes spp. mosquitoes—causing fever and debilitating joint pain, with frequent long-term health implications and high morbidity. The CHIKV lifecycle is poorly understood and specific antiviral therapeutics or vaccines are lacking. In this study, we investigated the role of host-cell chloride (Cl-) channels on CHIKV replication.We demonstrate that specific pharmacological Cl- channel inhibitors significantly inhibit CHIKV replication in a dose-dependent manner, suggesting that Cl-channels are pro-viral factors in human cells. Further analysis of the effect of the inhibitors on CHIKV attachment, entry, viral protein expression and replicon replication demonstrated that Cl- channels are specifically required for efficient CHIKV genome replication. This was conserved in mosquito cells, where CHIKV replication and genome copy number was significantly reduced following Cl- channel inhibition. siRNA silencing identified chloride intracellular channels 1 and 4 (CLIC1 and CLIC4, respectively) as required for efficient CHIKV replication and protein affinity chromatography showed low levels of CLIC1 in complex with CHIKV nsP3, an essential component of the viral replication machinery. In summary, for the first time we demonstrate that efficient replication of the CHIKV genome depends on cellular Cl- channels, in both human and mosquito cells and identifies CLIC1 and CLIC4 as agonists of CHIKV replication in human cells. We observe a modest interaction, either direct or indirect, between CLIC1 and nsP3 and hypothesize that CLIC1 may play a role in the formation/maintenance of CHIKV replication complexes. These findings advance our molecular understanding of CHIKV replication and identify potential druggable targets for the treatment and prevention of CHIKV mediated disease.
Output:
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Chikungunya virus (CHIKV) is a mosquito-borne virus that infects humans and causes chikungunya fever—characterized by fever, rash and chronic arthralgia. Treatment of chikungunya fever is limited to the alleviation of the symptoms and no vaccine is available to prevent infection. Consequently, new anti-CHIKV therapies or targets are urgently required. Since its initial isolation in Tanzania in 1952, CHIKV has spread widely across tropical/sub-tropical and more temperate regions. It has been responsible for epidemics in >70 different regions of the world, resulting in high morbidity and financial burden. Despite this, the CHIKV lifecycle is poorly understood. Here, we demonstrate for the first time that CHIKV requires host-cell ion channels that mediate chloride ion (Cl-) flux through the membranes of infected cells, to complete its lifecycle. Specifically, using pharmacological compounds, we show that Cl- channels are required for efficient replication of the virus genome, identify two specific channels (CLIC1 and CLIC4) required for replication and demonstrate that CLIC1 may interact with viral non-structural protein 3 (nsP3)—an essential component of the CHIKV replicase complex. These findings advance our understanding of CHIKV replication and identify potential druggable targets for the treatment and prevention of CHIKV mediated disease.
|
PLOS15
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The formation of protein-protein complexes is essential for proteins to perform their physiological functions in the cell. Mutations that prevent the proper formation of the correct complexes can have serious consequences for the associated cellular processes. Since experimental determination of protein-protein binding affinity remains difficult when performed on a large scale, computational methods for predicting the consequences of mutations on binding affinity are highly desirable. We show that a scoring function based on interface structure profiles collected from analogous protein-protein interactions in the PDB is a powerful predictor of protein binding affinity changes upon mutation. As a standalone feature, the differences between the interface profile score of the mutant and wild-type proteins has an accuracy equivalent to the best all-atom potentials, despite being two orders of magnitude faster once the profile has been constructed. Due to its unique sensitivity in collecting the evolutionary profiles of analogous binding interactions and the high speed of calculation, the interface profile score has additional advantages as a complementary feature to combine with physics-based potentials for improving the accuracy of composite scoring approaches. By incorporating the sequence-derived and residue-level coarse-grained potentials with the interface structure profile score, a composite model was constructed through the random forest training, which generates a Pearson correlation coefficient >0.8 between the predicted and observed binding free-energy changes upon mutation. This accuracy is comparable to, or outperforms in most cases, the current best methods, but does not require high-resolution full-atomic models of the mutant structures. The binding interface profiling approach should find useful application in human-disease mutation recognition and protein interface design studies.
Output:
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Few proteins carry out their tasks in isolation. Instead, proteins combine with each other in complicated ways that can be affected by either the natural genetic variation that occurs among people or by disease causing mutations such as those that occur in cancer or in genetic disorders. To understand how these mutations affect our health, it is necessary to understand how mutations can affect the strength of the interactions that bind proteins together. This is a difficult task to do in a laboratory on a large scale and scientists are increasingly turning to computational methods to predict these effects in advance. We show that by looking at the multiple alignments of similar protein-protein complex structures at the interface regions, new constraints based on the evolution of the three dimensional structures of proteins can be made to predict which mutations are compatible with two proteins interacting and which are not.
|
PLOS16
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration—defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise.
Output:
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Mitochondrial dysfunction is associated with a number of metabolic and neurological diseases such as Leigh syndrome and progressive blindness. Increased oxidative stress, which is often associated with mitochondrial dysfunction, is thought to be a common cause of disease progression. Here, we identified nuclear genes that encode mitochondrial proteins, whose loss causes the demise of photoreceptor neurons. Contrary to the common idea that this degeneration is triggered by elevated levels of oxidative stress, we find no change in the levels of oxidative stress. We show that activating photoreceptor neurons with light significantly increases energy production, and that this process is required to sustain their activity. Mitochondrial dysfunction impairs this capacity and leads to a premature termination of the light response. This in turn impairs the cycling of the light-sensitive receptor Rhodopsin in photoreceptors, and Rhodopsin accumulates in the cell inducing toxicity. This distinct mechanism of degeneration suggests that different mitochondrial diseases may follow different paths of disease progression and would hence respond differently to treatments.
|
PLOS17
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: For many complex traits, genetic variants have been found associated. However, it is still mostly unclear through which downstream mechanism these variants cause these phenotypes. Knowledge of these intermediate steps is crucial to understand pathogenesis, while also providing leads for potential pharmacological intervention. Here we relied upon natural human genetic variation to identify effects of these variants on trans-gene expression (expression quantitative trait locus mapping, eQTL) in whole peripheral blood from 1,469 unrelated individuals. We looked at 1,167 published trait- or disease-associated SNPs and observed trans-eQTL effects on 113 different genes, of which we replicated 46 in monocytes of 1,490 different individuals and 18 in a smaller dataset that comprised subcutaneous adipose, visceral adipose, liver tissue, and muscle tissue. HLA single-nucleotide polymorphisms (SNPs) were 10-fold enriched for trans-eQTLs: 48% of the trans-acting SNPs map within the HLA, including ulcerative colitis susceptibility variants that affect plausible candidate genes AOAH and TRBV18 in trans. We identified 18 pairs of unlinked SNPs associated with the same phenotype and affecting expression of the same trans-gene (21 times more than expected, P<10−16). This was particularly pronounced for mean platelet volume (MPV): Two independent SNPs significantly affect the well-known blood coagulation genes GP9 and F13A1 but also C19orf33, SAMD14, VCL, and GNG11. Several of these SNPs have a substantially higher effect on the downstream trans-genes than on the eventual phenotypes, supporting the concept that the effects of these SNPs on expression seems to be much less multifactorial. Therefore, these trans-eQTLs could well represent some of the intermediate genes that connect genetic variants with their eventual complex phenotypic outcomes.
Output:
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Many genetic variants have been found associated with diseases. However, for many of these genetic variants, it remains unclear how they exert their effect on the eventual phenotype. We investigated genetic variants that are known to be associated with diseases and complex phenotypes and assessed whether these variants were also associated with gene expression levels in a set of 1,469 unrelated whole blood samples. For several diseases, such as type 1 diabetes and ulcerative colitis, we observed that genetic variants affect the expression of genes, not implicated before. For complex traits, such as mean platelet volume and mean corpuscular volume, we observed that independent genetic variants on different chromosomes influence the expression of exactly the same genes. For mean platelet volume, these genes include well-known blood coagulation genes but also genes with still unknown functions. These results indicate that, by systematically correlating genetic variation with gene expression levels, it is possible to identify downstream genes, which provide important avenues for further research.
|
PLOS18
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The splicing regulator Polypyrimidine Tract Binding Protein (PTBP1) has four RNA binding domains that each binds a short pyrimidine element, allowing recognition of diverse pyrimidine-rich sequences. This variation makes it difficult to evaluate PTBP1 binding to particular sites based on sequence alone and thus to identify target RNAs. Conversely, transcriptome-wide binding assays such as CLIP identify many in vivo targets, but do not provide a quantitative assessment of binding and are informative only for the cells where the analysis is performed. A general method of predicting PTBP1 binding and possible targets in any cell type is needed. We developed computational models that predict the binding and splicing targets of PTBP1. A Hidden Markov Model (HMM), trained on CLIP-seq data, was used to score probable PTBP1 binding sites. Scores from this model are highly correlated (ρ = −0.9) with experimentally determined dissociation constants. Notably, we find that the protein is not strictly pyrimidine specific, as interspersed Guanosine residues are well tolerated within PTBP1 binding sites. This model identifies many previously unrecognized PTBP1 binding sites, and can score PTBP1 binding across the transcriptome in the absence of CLIP data. Using this model to examine the placement of PTBP1 binding sites in controlling splicing, we trained a multinomial logistic model on sets of PTBP1 regulated and unregulated exons. Applying this model to rank exons across the mouse transcriptome identifies known PTBP1 targets and many new exons that were confirmed as PTBP1-repressed by RT-PCR and RNA-seq after PTBP1 depletion. We find that PTBP1 dependent exons are diverse in structure and do not all fit previous descriptions of the placement of PTBP1 binding sites. Our study uncovers new features of RNA recognition and splicing regulation by PTBP1. This approach can be applied to other multi-RRM domain proteins to assess binding site degeneracy and multifactorial splicing regulation.
Output:
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A key step in the regulation of mammalian genes is the splicing of the messenger RNA precursor to produce a mature mRNA that can be translated into a particular protein needed by the cell. Through the process of alternative splicing, mRNAs encoding different proteins can be derived from the same primary gene transcript. The regulation of this process plays essential roles in the development of differentiated tissues and is mediated by special pre-mRNA binding proteins. To understand how these proteins control gene expression, one must characterize what they recognize in RNA and identify these binding sites across the genome in order to predict their targets. Models that allow this prediction are essential to understanding developmental regulatory programs and their perturbation by disease causing mutations. In this study, we use statistical methods to build models of RNA recognition by the important splicing regulator PTBP1 and then apply these models to predict PTBP1 regulation of new gene transcripts. We show that PTBP1 has different specificity for RNA than was previously recognized and that its target exons are more diverse than was known before. There are many similar splicing regulators in mammalian cells, and these analyses provide a general framework for the computational analysis of their RNA binding and target identification.
|
PLOS19
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Phages play critical roles in the survival and pathogenicity of their hosts, via lysogenic conversion factors, and in nutrient redistribution, via cell lysis. Analyses of phage- and viral-encoded genes in environmental samples provide insights into the physiological impact of viruses on microbial communities and human health. However, phage ORFs are extremely diverse of which over 70% of them are dissimilar to any genes with annotated functions in GenBank. Better identification of viruses would also aid in better detection and diagnosis of disease, in vaccine development, and generally in better understanding the physiological potential of any environment. In contrast to enzymes, viral structural protein function can be much more challenging to detect from sequence data because of low sequence conservation, few known conserved catalytic sites or sequence domains, and relatively limited experimental data. We have designed a method of predicting phage structural protein sequences that uses Artificial Neural Networks (ANNs). First, we trained ANNs to classify viral structural proteins using amino acid frequency; these correctly classify a large fraction of test cases with a high degree of specificity and sensitivity. Subsequently, we added estimates of protein isoelectric points as a feature to ANNs that classify specialized families of proteins, namely major capsid and tail proteins. As expected, these more specialized ANNs are more accurate than the structural ANNs. To experimentally validate the ANN predictions, several ORFs with no significant similarities to known sequences that are ANN-predicted structural proteins were examined by transmission electron microscopy. Some of these self-assembled into structures strongly resembling virion structures. Thus, our ANNs are new tools for identifying phage and potential prophage structural proteins that are difficult or impossible to detect by other bioinformatic analysis. The networks will be valuable when sequence is available but in vitro propagation of the phage may not be practical or possible.
Output:
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Bacteriophages are extremely abundant and diverse biological entities. All phage particles are comprised of nucleic acids and structural proteins, with few other packaged proteins. Despite their simplicity and abundance, more than 70% of phage sequences in the viral Reference Sequence database encode proteins with unknown function based on FASTA annotations. As a result, the use of sequence similarity is often insufficient for detecting virus structural proteins among unknown viral sequences. Viral structural protein function is challenging to detect from sequence data because structural proteins possess few known conserved catalytic motifs and sequence domains. To address these issues we investigated the use of Artificial Neural Networks as an alternative means of predicting function. Here, we trained thousands of networks using the amino acid frequency of structural protein sequences and identified the optimal architectures with the highest accuracies. Some hypothetical protein sequences detected by our networks were expressed and visualized by TEM, and produced images that strongly resemble virion structures. Our results support the utility of our neural networks in predicting the functions of unknown viral sequences.
|
PLOS20
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: DNA looping mediated by transcription factors plays critical roles in prokaryotic gene regulation. The “genetic switch” of bacteriophage λ determines whether a prophage stays incorporated in the E. coli chromosome or enters the lytic cycle of phage propagation and cell lysis. Past studies have shown that long-range DNA interactions between the operator sequences OR and OL (separated by 2.3 kb), mediated by the λ repressor CI (accession number P03034), play key roles in regulating the λ switch. In vitro, it was demonstrated that DNA segments harboring the operator sequences formed loops in the presence of CI, but CI-mediated DNA looping has not been directly visualized in vivo, hindering a deep understanding of the corresponding dynamics in realistic cellular environments. We report a high-resolution, single-molecule imaging method to probe CI-mediated DNA looping in live E. coli cells. We labeled two DNA loci with differently colored fluorescent fusion proteins and tracked their separations in real time with ∼40 nm accuracy, enabling the first direct analysis of transcription-factor-mediated DNA looping in live cells. Combining looping measurements with measurements of CI expression levels in different operator mutants, we show quantitatively that DNA looping activates transcription and enhances repression. Further, we estimated the upper bound of the rate of conformational change from the unlooped to the looped state, and discuss how chromosome compaction may impact looping kinetics. Our results provide insights into transcription-factor-mediated DNA looping in a variety of operator and CI mutant backgrounds in vivo, and our methodology can be applied to a broad range of questions regarding chromosome conformations in prokaryotes and higher organisms.
Output:
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One mechanism cells use to regulate gene expression is DNA looping, whereby two distant DNA sites are brought together by regulatory proteins. The looping then either enhances interactions between other regulatory proteins bound at the separate sites or brings those regulatory proteins close to RNA polymerase at the promoter. Recent work in bacteriophage λ has suggested that DNA looping mediated by a transcription factor called λ repressor CI plays a critical role in regulating the expression of λ genes and consequently in determining the fate of the host E. coli bacterial cells. CI-mediated DNA looping has been directly demonstrated in vitro, but it has only been indirectly inferred in vivo. For the current study we developed a method to visualize CI-mediated DNA looping in individual live E. coli cells. We labeled two DNA sites—one each side of the proposed loop—with differently colored fluorescent fusion proteins, allowing us to measure their separation with an accuracy of a few tens of nanometers. Using this method, we directly analyzed CI-mediated DNA looping, providing insight into how transcription factor-mediated DNA looping influences gene regulation in live E. coli cells. Our methodology can be applied to a broad range of questions regarding chromosome conformation in prokaryotes and higher organisms.
|
PLOS21
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Rabies is a neglected zoonotic disease. Given the low incidence, apart from the existing reporting syst, there is a need to look for other means of case detection strategies for rabies. Contact tracing is one such method to efficiently capture information.
To find out the rabid status of biting animal through contact tracing and to determine health seeking behavior of the bite victims.
An exploratory study using contact tracing was conducted during the first quarter of 2017 in villages coming under three Public Health Centers. The households of the bite victims were visited and details of rabies exposure obtained from the bite victim/ adult responsible respondent using a standardized questionnaire.
A total of 69 dog/cat bite cases were identified. 69.5% of bites were by stray dogs. 97.1% bite victims had Category III bites. Only 4.5% bite victims had taken PEP. 70.1% of animal bite cases were administered ARV. Only 7.2% bite victims had exposure to probable rabid animals. All dog bite victims were alive after 3 months of follow up.
Contact tracing was successful in case detection of probable rabid animal exposures and suitable for a period of one year.
Output:
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In India, Rabies is a neglected zoonotic disease and the burden of rabies is usually not captured by the health system due to varied reasons. Hence, an exploratory study was attempted to find out the rabid status of the biting animal through contact tracing during the first quarter of 2017 in villages coming under three Public Health Centers. A total of 69 dog/cat bite cases were identified. Majority of bites were by stray dogs, Category-III, exposure to non cases and few received PEP. Percentage of bite victims who actually required PEP was calculated. These findings support the fact that contact tracing can be used as an additional tool by the health care provider for measurement of rabid animal bites, where resources are scarce, reporting systems are weak and priorities for disease vary. A rabies check list/score card to be made available at Public Health Centers, which shall ensure better utilization of limited but lifesaving Rabies Immunobiologicals.
|
PLOS22
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: GWAS identified variants associated with birth weight (BW), childhood obesity (CO) and childhood BMI (CBMI), and placenta is a critical organ for fetal development and postnatal health. We examined the role of placental transcriptome and eQTLs in mediating the genetic causes for BW, CO and CBMI, and applied integrative analysis (Colocalization and MetaXcan). GWAS loci associated with BW, CO, and CBMI were substantially enriched for placenta eQTLs (6.76, 4.83 and 2.26 folds, respectively). Importantly, compared to eQTLs of adult tissues, only placental eQTLs contribute significantly to both anthropometry outcomes at birth (BW) and childhood phenotypes (CO/CBMI). Eight, six and one transcripts colocalized with BW, CO and CBMI risk loci, respectively. Our study reveals that placental transcription in utero likely plays a key role in determining postnatal body size, and as such may hold new possibilities for therapeutic interventions to prevent childhood obesity.
Output:
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Genetic studies (e.g GWAS) revealed substantial heritability on birth weight (BW), childhood obesity (CO) and childhood body mass index (CBMI), however, the etiological mechanisms and relevant tissue(s) underlying these traits/conditions are not clear. We incorporated the data from largest GWASes to date and placenta expressional quantitative trait loci (eQTL) that have been newly published, and showed the variants associated with BW, CO and CBMI were substantially enriched for placenta eQTLs (6.76, 4.83 and 2.26 folds, respectively). Importantly, compared to eQTLs in 7 adult tissues such as adipose and liver, only eQTLs in the placenta were found to contribute significantly not only to anthropometry outcomes at birth (BW) but also to childhood phenotypes (CO/CBMI). Further, we employed COLOC and MetaXcan analyses and identified placenta transcripts potential mediate the genetic effect of BW/CO/CBMI GWAS loci. In summary, our study strongly supports a key role for the placenta in determining BW, CO and CMBI at the molecular level, and pinpointed genes whose expression levels in placenta potentially influences BW and CO risk.
|
PLOS23
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: As increasingly more genomes are sequenced, the vast majority of proteins may only be annotated computationally, given experimental investigation is extremely costly. This highlights the need for computational methods to determine protein functions quickly and reliably. We believe dividing a protein family into subtypes which share specific functions uncommon to the whole family reduces the function annotation problem’s complexity. Hence, this work’s purpose is to detect isofunctional subfamilies inside a family of unknown function, while identifying differentiating residues. Similarity between protein pairs according to various properties is interpreted as functional similarity evidence. Data are integrated using genetic programming and provided to a spectral clustering algorithm, which creates clusters of similar proteins. The proposed framework was applied to well-known protein families and to a family of unknown function, then compared to ASMC. Results showed our fully automated technique obtained better clusters than ASMC for two families, besides equivalent results for other two, including one whose clusters were manually defined. Clusters produced by our framework showed great correspondence with the known subfamilies, besides being more contrasting than those produced by ASMC. Additionally, for the families whose specificity determining positions are known, such residues were among those our technique considered most important to differentiate a given group. When run with the crotonase and enolase SFLD superfamilies, the results showed great agreement with this gold-standard. Best results consistently involved multiple data types, thus confirming our hypothesis that similarities according to different knowledge domains may be used as functional similarity evidence. Our main contributions are the proposed strategy for selecting and integrating data types, along with the ability to work with noisy and incomplete data; domain knowledge usage for detecting subfamilies in a family with different specificities, thus reducing the complexity of the experimental function characterization problem; and the identification of residues responsible for specificity.
Output:
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The knowledge of protein functions is central for understanding life at a molecular level and has huge biochemical and pharmaceutical implications. However, despite best research efforts, a substantial and ever-increasing number of proteins predicted by genome sequencing projects still lack functional annotations. Computational methods are required to determine protein functions quickly and reliably since experimental investigation is difficult and costly. Considering literature shows combining various types of information is crucial for functionally annotating proteins, such methods must be able to integrate data from different sources which may be scattered, non-standardized, incomplete, and noisy. Many protein families are composed of proteins with different folds and functions. In such cases, the division into subtypes which share specific functions uncommon to the family as a whole may lead to important information about the function and structure of a related protein of unknown function, as well as about the functional diversification acquired by the family during evolution. This work’s purpose is to automatically detect isofunctional subfamilies in a protein family of unknown function, as well as identify residues responsible for differentiation. We integrate data and then provide it to a clustering algorithm, which creates clusters of similar proteins we found correspond to same-specificity subfamilies.
|
PLOS24
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Molecular genetic approaches typically detect recombination in microbes regardless of assumed asexuality. However, genetic data have shown the AIDS-associated pathogen Penicillium marneffei to have extensive spatial genetic structure at local and regional scales, and although there has been some genetic evidence that a sexual cycle is possible, this haploid fungus is thought to be genetically, as well as morphologically, asexual in nature because of its highly clonal population structure. Here we use comparative genomics, experimental mixed-genotype infections, and population genetic data to elucidate the role of recombination in natural populations of P. marneffei. Genome wide comparisons reveal that all the genes required for meiosis are present in P. marneffei, mating type genes are arranged in a similar manner to that found in other heterothallic fungi, and there is evidence of a putatively meiosis-specific mutational process. Experiments suggest that recombination between isolates of compatible mating types may occur during mammal infection. Population genetic data from 34 isolates from bamboo rats in India, Thailand and Vietnam, and 273 isolates from humans in China, India, Thailand, and Vietnam show that recombination is most likely to occur across spatially and genetically limited distances in natural populations resulting in highly clonal population structure yet sexually reproducing populations. Predicted distributions of three different spatial genetic clusters within P. marneffei overlap with three different bamboo rat host distributions suggesting that recombination within hosts may act to maintain population barriers within P. marneffei.
Output:
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Fungal pathogen populations show patterns ranging from globally recombining to endemic and clonal. Among the most genetically and spatially restricted fungi is the highly clonal pathogen Penicillium marneffei, an endemic AIDS-associated pathogen in Southeast Asia. Previous studies have shown that P. marneffei has a pattern of extreme clonality despite the ability to disperse across wide distances and the presence of mating type genes that are required for sexual recombination. In this study we used genetic markers, comparative genomics, experimental data, and spatial models to determine the influence of sex on P. marneffei populations, and we found that although there was substantial evidence of sexual recombination, most of the recombination in natural populations was limited to sexual neighborhoods, amongst genetically similar and spatially close individuals. Based on the results of experiments and spatial models we found support for sex occurring in bamboo rats that are known to harbor P. marneffei and the pathogens sexual neighborhoods. Our study suggests that the high levels of effective clonality and endemicity found in P. marneffei may have more to do with specific host interactions than with an innate inability to generate population genetic diversity through sexual recombination.
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PLOS25
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: There is a current interest in quantifying time-varying connectivity (TVC) based on neuroimaging data such as fMRI. Many methods have been proposed, and are being applied, revealing new insight into the brain’s dynamics. However, given that the ground truth for TVC in the brain is unknown, many concerns remain regarding the accuracy of proposed estimates. Since there exist many TVC methods it is difficult to assess differences in time-varying connectivity between studies. In this paper, we present tvc_benchmarker, which is a Python package containing four simulations to test TVC methods. Here, we evaluate five different methods that together represent a wide spectrum of current approaches to estimating TVC (sliding window, tapered sliding window, multiplication of temporal derivatives, spatial distance and jackknife correlation). These simulations were designed to test each method’s ability to track changes in covariance over time, which is a key property in TVC analysis. We found that all tested methods correlated positively with each other, but there were large differences in the strength of the correlations between methods. To facilitate comparisons with future TVC methods, we propose that the described simulations can act as benchmark tests for evaluation of methods. Using tvc_benchmarker researchers can easily add, compare and submit their own TVC methods to evaluate its performance.
Output:
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Time-varying connectivity attempts to quantify the fluctuating covariance relationship between two or more regions through time. In recent years, it has become popular to do this with fMRI neuroimaging data. There have been many methods proposed to quantify time-varying connectivity, but very few attempts to systematically compare them. In this paper, we present tvc_benchmarker, which is a python package that consists of four simulations. The parameters of the data are justified on fMRI signal properties. Five different methods are evaluated in this paper, but other researchers can use tvc_benchmarker to evaluate their methodologies and their results can be submitted to be included in future reports. Methods are evaluated on their ability to track a fluctuating covariance parameter between time series. Of the evaluated methods, the jackknife correlation method performed the best at tracking a fluctuating covariance parameter in these four simulations.
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PLOS26
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: For the last three decades, evolutionary biologists have sought to understand which factors modulate the evolution of parasite virulence. Although theory has identified several of these modulators, their effect has seldom been analysed experimentally. We investigated the role of two such major factors—the mode of transmission, and host adaptation in response to parasite evolution—in the evolution of virulence of the plant virus Cucumber mosaic virus (CMV) in its natural host Arabidopsis thaliana. To do so, we serially passaged three CMV strains under strict vertical and strict horizontal transmission, alternating both modes of transmission. We quantified seed (vertical) transmission rate, virus accumulation, effect on plant growth and virulence of evolved and non-evolved viruses in the original plants and in plants derived after five passages of vertical transmission. Our results indicated that vertical passaging led to adaptation of the virus to greater vertical transmission, which was associated with reductions of virus accumulation and virulence. On the other hand, horizontal serial passages did not significantly modify virus accumulation and virulence. The observed increases in CMV seed transmission, and reductions in virus accumulation and virulence in vertically passaged viruses were due also to reciprocal host adaptation during vertical passages, which additionally reduced virulence and multiplication of vertically passaged viruses. This result is consistent with plant-virus co-evolution. Host adaptation to vertically passaged viruses was traded-off against reduced resistance to the non-evolved viruses. Thus, we provide evidence of the key role that the interplay between mode of transmission and host-parasite co-evolution has in determining the evolution of virulence.
Output:
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Virulence is a key property of parasites, and is linked to the emergence of new diseases and to the reduction of ecosystem biodiversity. Consequently, scientists have devoted a great effort to build theoretical models that predict which factors may modulate virulence evolution. However, whether (and how) these factors affect virulence evolution has been seldom analysed experimentally. Using the plant virus Cucumber mosaic virus (CMV) and its natural host Arabidopsis thaliana, we studied the role of two such factors: the mode of transmission, and host adaptation in response to parasite evolution. We serially passaged CMV under strict vertical and strict horizontal transmission, and a combination of both. Subsequently, we analysed differences in CMV seed (vertical) transmission rate, accumulation and virulence between evolved and non-evolved viruses. We also compared whether these differences varied in original plants and in plants evolved during vertical passaging. Vertical passaging increased CMV seed transmission, and reduced accumulation and virulence, while horizontal passaging had no effect. Changes during vertical passaging were determined also by reciprocal host adaptation, which additionally reduced virulence and accumulation of vertically transmitted viruses. Hence, we provide evidence that the interplay between the transmission mode and host-parasite co-evolution is central in determining virulence evolution.
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PLOS27
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Schistosomiasis is a helminthic disease that affects more than 200 million people. An effective vaccine would be a major step towards eliminating the disease. Studies suggest that T follicular helper (Tfh) cells provide help to B cells to generate the long-term humoral immunity, which would be a crucial component of successful vaccines. Thus, understanding the biological characteristics of Tfh cells in patients with schistosomiasis, which has never been explored, is essential for vaccine design.
In this study, we investigated the biological characteristics of peripheral memory Tfh cells in schistosomiasis patients by flow cytometry. Our data showed that the frequencies of total and activated peripheral memory Tfh cells in patients were significantly increased during Schistosoma japonicum infection. Moreover, Tfh2 cells, which were reported to be a specific subpopulation to facilitate the generation of protective antibodies, were increased more greatly than other subpopulations of total peripheral memory Tfh cells in patients with schistosomiasis japonica. More importantly, our result showed significant correlations of the percentage of Tfh2 cells with both the frequency of plasma cells and the level of IgG antibody. In addition, our results showed that the percentage of T follicular regulatory (Tfr) cells was also increased in patients with schistosomiasis.
Our report is the first characterization of peripheral memory Tfh cells in schistosomasis patients, which not only provides potential targets to improve immune response to vaccination, but also is important for the development of vaccination strategies to control schistosomiasis.
Output:
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Schistosomiasis affects more than 200 million people worldwide and causes more than 280,000 deaths per year. Current control strategies are based on chemotherapy, but recurrent reinfection of people living in endemic areas makes researchers search for an effective vaccine to provide long-term protection against schistosomiasis. The generation of long-lived high-affinity antibodies after vaccination is a pivotal step for anti-schistosome vaccine to eliminate schistosomiasis. Considering it is well-known that Tfh cells are specialized effector CD4+ T cells that provide help for germinal center (GC) formation and induce GC B cells to develop protective antibody responses, understanding the biology of Tfh cells in schistosomiasis patients is fundamental for vaccine strategy development. Here, for the first time, we documented increased frequencies of total and activated peripheral memory Tfh cells in schistosomiasis patients. Furthermore, we showed that Tfh2 cells were a major contributor to increased frequency of peripheral memory Tfh cells in patients with schistosomiasis japonica. More importantly, we found the significant correlations of the percentage of Tfh2 cells with both the frequency of plasma cells and the level of total IgG antibody in schistosomiasis patients.
|
PLOS28
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The correspondence between protein sequences and structures, or sequence-structure map, relates to fundamental aspects of structural, evolutionary and synthetic biology. The specifics of the mapping, such as the fraction of accessible sequences and structures, or the sequences' ability to fold fast, are dictated by the type of interactions between the monomers that compose the sequences. The set of possible interactions between monomers is encapsulated by the potential energy function. In this study, I explore the impact of the relative forces of the potential on the architecture of the sequence-structure map. My observations rely on simple exact models of proteins and random samples of the space of potential energy functions of binary alphabets. I adopt a graph perspective and study the distribution of viable sequences and the structures they produce, as networks of sequences connected by point mutations. I observe that the relative proportion of attractive, neutral and repulsive forces defines types of potentials, that induce sequence-structure maps of vastly different architectures. I characterize the properties underlying these differences and relate them to the structure of the potential. Among these properties are the expected number and relative distribution of sequences associated to specific structures and the diversity of structures as a function of sequence divergence. I study the types of binary potentials observed in natural amino acids and show that there is a strong bias towards only some types of potentials, a bias that seems to characterize the folding code of natural proteins. I discuss implications of these observations for the architecture of the sequence-structure map of natural proteins, the construction of random libraries of peptides, and the early evolution of the natural amino acid alphabet.
Output:
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If we were to design a proteome, what types and what proportion of amino acids would we use in order to optimize properties such as the diversity of sequences and structures, their robustness to mutations, or their ability to fold efficiently? Here, I use simple models to study the sequence-structure map of proteins from a design and evolutionary perspective. These models can be used to explore all sequences and structures, as a function of the types of interactions encoded by the sequence. I study the range of possible binary interactions between monomers, which include natural and artificial amino acids. The results indicate that different amino acid compositions induce vastly different sequences-structure maps. I classify and study the properties of these maps and relate their features back to the type of energy interactions. I compare these observations to the types of interactions observed in natural amino acids. My observations provide insights for our current view of the sequence-structure map of natural proteins, guiding principles for the construction of random libraries of peptides, and suggests constraints for the early evolution of the natural amino acid alphabet.
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PLOS29
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Cells employ multiple levels of regulation, including transcriptional and translational regulation, that drive core biological processes and enable cells to respond to genetic and environmental changes. Small-molecule metabolites are one category of critical cellular intermediates that can influence as well as be a target of cellular regulations. Because metabolites represent the direct output of protein-mediated cellular processes, endogenous metabolite concentrations can closely reflect cellular physiological states, especially when integrated with other molecular-profiling data. Here we develop and apply a network reconstruction approach that simultaneously integrates six different types of data: endogenous metabolite concentration, RNA expression, DNA variation, DNA–protein binding, protein–metabolite interaction, and protein–protein interaction data, to construct probabilistic causal networks that elucidate the complexity of cell regulation in a segregating yeast population. Because many of the metabolites are found to be under strong genetic control, we were able to employ a causal regulator detection algorithm to identify causal regulators of the resulting network that elucidated the mechanisms by which variations in their sequence affect gene expression and metabolite concentrations. We examined all four expression quantitative trait loci (eQTL) hot spots with colocalized metabolite QTLs, two of which recapitulated known biological processes, while the other two elucidated novel putative biological mechanisms for the eQTL hot spots.
Output:
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It is now possible to score variations in DNA across whole genomes, RNA levels and alternative isoforms, metabolite levels, protein levels and protein state information, protein–protein interactions, and protein–DNA interactions, in a comprehensive fashion in populations of individuals. Interactions among these molecular entities define the complex web of biological processes that give rise to all higher order phenotypes, including disease. The development of analytical approaches that simultaneously integrate different dimensions of data is essential if we are to extract the meaning from large-scale data to elucidate the complexity of living systems. Here, we use a novel Bayesian network reconstruction algorithm that simultaneously integrates DNA variation, RNA levels, metabolite levels, protein–protein interaction data, protein–DNA binding data, and protein–small-molecule interaction data to construct molecular networks in yeast. We demonstrate that these networks can be used to infer causal relationships among genes, enabling the identification of novel genes that modulate cellular regulation. We show that our network predictions either recapitulate known biology or can be prospectively validated, demonstrating a high degree of accuracy in the predicted network.
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PLOS30
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The sexually transmitted bacterium Neisseria gonorrhoeae has developed resistance to all antibiotic classes that have been used for treatment and strains resistant to multiple antibiotic classes have evolved. In many countries, there is only one antibiotic remaining for empirical N. gonorrhoeae treatment, and antibiotic management to counteract resistance spread is urgently needed. Understanding dynamics and drivers of resistance spread can provide an improved rationale for antibiotic management. In our study, we first used antibiotic resistance surveillance data to estimate the rates at which antibiotic-resistant N. gonorrhoeae spread in two host populations, heterosexual men (HetM) and men who have sex with men (MSM). We found higher rates of spread for MSM (0.86 to 2.38 y−1, mean doubling time: 6 months) compared to HetM (0.24 to 0.86 y−1, mean doubling time: 16 months). We then developed a dynamic transmission model to reproduce the observed dynamics of N. gonorrhoeae transmission in populations of heterosexual men and women (HMW) and MSM. We parameterized the model using sexual behavior data and calibrated it to N. gonorrhoeae prevalence and incidence data. In the model, antibiotic-resistant N. gonorrhoeae spread with a median rate of 0.88 y−1 in HMW and 3.12 y−1 in MSM. These rates correspond to median doubling times of 9 (HMW) and 3 (MSM) months. Assuming no fitness costs, the model shows the difference in the host population’s treatment rate rather than the difference in the number of sexual partners explains the differential spread of resistance. As higher treatment rates result in faster spread of antibiotic resistance, treatment recommendations for N. gonorrhoeae should carefully balance prevention of infection and avoidance of resistance spread.
Output:
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More and more infectious disease treatments fail because the causative pathogens are resistant to the drugs used for treatment. For the treatment of Neisseria gonorrhoeae, a sexually transmitted bacterium, drug resistance is a particularly big problem: there is only a single antibiotic left that is recommended for treatment. We aimed to understand how antibiotic-resistant N. gonorrhoeae spread in a sexually active host population and how the spread of resistance can be slowed. From antibiotic resistance surveillance data, we first estimated the rate at which antibiotic-resistant N. gonorrhoeae spread. Second, we reproduced the observed dynamics in a mathematical model describing the transmission between hosts. We found that antibiotic-resistant N. gonorrhoeae spread faster in host populations of men who have sex with men than in host populations of heterosexuals. We could attribute the faster spread of resistant pathogens to higher treatment rates. This finding implies that promoting screening to control antibiotic-resistant N. gonorrhoeae could in fact accelerate their spread.
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PLOS31
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Paracoccidioidomycosis (PCM), caused by Paracoccidioides brasiliensis, is the most prevalent invasive fungal disease in South America. Systemic mycoses are the 10th most common cause of death among infectious diseases in Brazil and PCM is responsible for more than 50% of deaths due to fungal infections. PCM is typically treated with sulfonamides, amphotericin B or azoles, although complete eradication of the fungus may not occur and relapsing disease is frequently reported. A 15-mer peptide from the major diagnostic antigen gp43, named P10, can induce a strong T-CD4+ helper-1 immune response in mice. The TEPITOPE algorithm and experimental data have confirmed that most HLA-DR molecules can present P10, which suggests that P10 is a candidate antigen for a PCM vaccine. In the current work, the therapeutic efficacy of plasmid immunization with P10 and/or IL-12 inserts was tested in murine models of PCM. When given prior to or after infection with P. brasiliensis virulent Pb 18 isolate, plasmid-vaccination with P10 and/or IL-12 inserts successfully reduced the fungal burden in lungs of infected mice. In fact, intramuscular administration of a combination of plasmids expressing P10 and IL-12 given weekly for one month, followed by single injections every month for 3 months restored normal lung architecture and eradicated the fungus in mice that were infected one month prior to treatment. The data indicate that immunization with these plasmids is a powerful procedure for prevention and treatment of experimental PCM, with the perspective of being also effective in human patients.
Output:
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Paracoccidioidomycosis (PCM) is the predominant systemic mycosis in Latin America causing half of the total deaths among systemic fungal infectious diseases in Brazil. Chemotherapy is the standard treatment, but the long time required, severe cases of immunosuppression and frequent relapses indicate that additional methods should be introduced such as immunotherapy combined with antifungal drugs. Previously, the protective activity of P10, a peptide derived from the major diagnostic antigen gp43, was demonstrated, alone or combined with chemotherapy. P10 elicited a vigorous IFN-γ mediated Th-1 immune response. Presently, the reduction of fungal load, and even sterilization, was attempted using a specific DNA vaccine encoding P10. Plasmid pcDNA3 expression vector with P10 insert was tested as a vaccine in intratracheally infected BALB/c and B10.A mice. Our results showed that vaccination with pP10 induced a significant reduction of the fungal burden in the lung. Co-vaccination of pP10 with a plasmid encoding mouse IL-12 proved to be even more effective in the elimination of the fungus with virtual sterilization in a long term infection and treatment assay system. The data suggest that immunization with these plasmids, without the need of an adjuvant, could be used in the prevention and treatment of PCM in human patients.
|
PLOS32
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Gene drives have enormous potential for the control of insect populations of medical and agricultural relevance. By preferentially biasing their own inheritance, gene drives can rapidly introduce genetic traits even if these confer a negative fitness effect on the population. We have recently developed gene drives based on CRISPR nuclease constructs that are designed to disrupt key genes essential for female fertility in the malaria mosquito. The construct copies itself and the associated genetic disruption from one homologous chromosome to another during gamete formation, a process called homing that ensures the majority of offspring inherit the drive. Such drives have the potential to cause long-lasting, sustainable population suppression, though they are also expected to impose a large selection pressure for resistance in the mosquito. One of these population suppression gene drives showed rapid invasion of a caged population over 4 generations, establishing proof of principle for this technology. In order to assess the potential for the emergence of resistance to the gene drive in this population we allowed it to run for 25 generations and monitored the frequency of the gene drive over time. Following the initial increase of the gene drive we observed a gradual decrease in its frequency that was accompanied by the spread of small, nuclease-induced mutations at the target gene that are resistant to further cleavage and restore its functionality. Such mutations showed rates of increase consistent with positive selection in the face of the gene drive. Our findings represent the first documented example of selection for resistance to a synthetic gene drive and lead to important design recommendations and considerations in order to mitigate for resistance in future gene drive applications.
Output:
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Gene drives are selfish genetic elements that are able to bias their own inheritance among offspring. Starting from very low frequencies they can rapidly invade a population in just a few generations, even when imposing a fitness cost. Gene drives based on the precise DNA cutting enzyme CRISPR have been shown recently to be highly efficient at copying themselves from one chromosome to the other during the process of gamete formation in mosquitoes, resulting in transmission to 99% of offspring instead of the 50% expected for a single gene copy. One proposed use for CRISPR-based gene drives is in the control of mosquitoes by designing the gene drive to target mosquito genes involved in fertility, thereby reducing their overall reproductive output and leading to population suppression. Like any intervention designed to suppress a population these gene drives are expected to select for mutations in the mosquito that are resistant to the drive and restore fertility to mosquitoes. We have analyzed the origin and selection of resistant alleles in caged populations of mosquitoes initiated with a gene drive construct targeting a female fertility gene. We find the selected alleles are in-frame insertions and deletions that are resistant to cleavage and restore female fertility. Our findings allow us to improve predictions on gene drive behaviour and to make concrete recommendations on how to improve future gene drive designs by decreasing the likelihood that they generate resistance.
|
PLOS33
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Proper functioning of working memory involves the expression of stimulus-selective persistent activity in pyramidal neurons of the prefrontal cortex (PFC), which refers to neural activity that persists for seconds beyond the end of the stimulus. The mechanisms which PFC pyramidal neurons use to discriminate between preferred vs. neutral inputs at the cellular level are largely unknown. Moreover, the presence of pyramidal cell subtypes with different firing patterns, such as regular spiking and intrinsic bursting, raises the question as to what their distinct role might be in persistent firing in the PFC. Here, we use a compartmental modeling approach to search for discriminatory features in the properties of incoming stimuli to a PFC pyramidal neuron and/or its response that signal which of these stimuli will result in persistent activity emergence. Furthermore, we use our modeling approach to study cell-type specific differences in persistent activity properties, via implementing a regular spiking (RS) and an intrinsic bursting (IB) model neuron. We identify synaptic location within the basal dendrites as a feature of stimulus selectivity. Specifically, persistent activity-inducing stimuli consist of activated synapses that are located more distally from the soma compared to non-inducing stimuli, in both model cells. In addition, the action potential (AP) latency and the first few inter-spike-intervals of the neuronal response can be used to reliably detect inducing vs. non-inducing inputs, suggesting a potential mechanism by which downstream neurons can rapidly decode the upcoming emergence of persistent activity. While the two model neurons did not differ in the coding features of persistent activity emergence, the properties of persistent activity, such as the firing pattern and the duration of temporally-restricted persistent activity were distinct. Collectively, our results pinpoint to specific features of the neuronal response to a given stimulus that code for its ability to induce persistent activity and predict differential roles of RS and IB neurons in persistent activity expression.
Output:
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Memory, referred to as the ability to retain, store and recall information, represents one of the most fundamental cognitive functions in daily life. A significant feature of memory processes is selectivity to particular events or items that are important to our survival and relevant to specific situations. For long-term memory, the selectivity to a specific stimulus is seen both at the behavioral as well as the cellular level. For working memory, a type of short-term memory involved in decision making and attention processes, stimulus selectivity has been observed in vivo using spatial working memory tasks. In addition, persistent activity, which is the cellular correlate of working memory, is also selective to specific stimuli for each neuron, suggesting that each neuron has a ‘memory field’. Our study proposes that both the location of incoming inputs onto the neuronal dendritic tree and specific temporal features of the neuronal response can be used to predict the emergence of persistent activity in two neuron models with different firing patterns, revealing possible mechanisms for generating and propagating stimulus-selectivity in working memory processes. The study also reveals that neurons with different firing patterns may have different roles in persistent activity expression.
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PLOS34
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Paenibacillus larvae, the etiological agent of the globally occurring epizootic American Foulbrood (AFB) of honey bees, causes intestinal infections in honey bee larvae which develop into systemic infections inevitably leading to larval death. Massive brood mortality might eventually lead to collapse of the entire colony. Molecular mechanisms of host-microbe interactions in this system and of differences in virulence between P. larvae genotypes are poorly understood. Recently, it was demonstrated that the degradation of the peritrophic matrix lining the midgut epithelium is a key step in pathogenesis of P. larvae infections. Here, we present the isolation and identification of PlCBP49, a modular, chitin-degrading protein of P. larvae and demonstrate that this enzyme is crucial for the degradation of the larval peritrophic matrix during infection. PlCBP49 contains a module belonging to the auxiliary activity 10 (AA10, formerly CBM33) family of lytic polysaccharide monooxygenases (LPMOs) which are able to degrade recalcitrant polysaccharides. Using chitin-affinity purified PlCBP49, we provide evidence that PlCBP49 degrades chitin via a metal ion-dependent, oxidative mechanism, as already described for members of the AA10 family. Using P. larvae mutants lacking PlCBP49 expression, we analyzed in vivo biological functions of PlCBP49. In the absence of PlCBP49 expression, peritrophic matrix degradation was markedly reduced and P. larvae virulence was nearly abolished. This indicated that PlCBP49 is a key virulence factor for the species P. larvae. The identification of the functional role of PlCBP49 in AFB pathogenesis broadens our understanding of this important family of chitin-binding and -degrading proteins, especially in those bacteria that can also act as entomopathogens.
Output:
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American Foulbrood and its etiological agent, Paenibacillus larvae, pose a serious threat to global honey bee health. So far, molecular mechanisms of host-microbe interactions are poorly understood in this system and no key virulence factor for the entire species has been identified. Here, we demonstrate that P. larvae expresses a chitin-binding and -degrading protein PlCBP49 harboring one module that belongs to the auxiliary activity 10 (AA10) family of lytic polysaccharide monooxygenases (LPMOs). We provide evidence that PlCBP49 degrades chitin via a metal ion-dependent, oxidative mechanism, as already described for other members of the AA10 enzyme family. Using P. larvae mutants lacking PlCBP49 expression, we demonstrate that PlCBP49 is crucial for the degradation of the chitin-rich peritrophic matrix, a key step in pathogenesis of P. larvae infections. In the absence of PlCBP49 expression the peritrophic matrix remained nearly intact and about 95% of the infected larvae survived infection. This clearly indicated that PlCBP49 is a key virulence factor of P. larvae. These results constitute important progress in our understanding of both P. larvae pathogenesis and the biological role of LPMOs in entomopathogens. Furthermore, knowing PlCBP49 and its role in pathogenesis opens new possibilities to develop curative measures for this disease.
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PLOS35
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Neurological impairments are frequently detected in children surviving cerebral malaria (CM), the most severe neurological complication of infection with Plasmodium falciparum. The pathophysiology and therapy of long lasting cognitive deficits in malaria patients after treatment of the parasitic disease is a critical area of investigation. In the present study we used several models of experimental malaria with differential features to investigate persistent cognitive damage after rescue treatment. Infection of C57BL/6 and Swiss (SW) mice with Plasmodium berghei ANKA (PbA) or a lethal strain of Plasmodium yoelii XL (PyXL), respectively, resulted in documented CM and sustained persistent cognitive damage detected by a battery of behavioral tests after cure of the acute parasitic disease with chloroquine therapy. Strikingly, cognitive impairment was still present 30 days after the initial infection. In contrast, BALB/c mice infected with PbA, C57BL6 infected with Plasmodium chabaudi chabaudi and SW infected with non lethal Plasmodium yoelii NXL (PyNXL) did not develop signs of CM, were cured of the acute parasitic infection by chloroquine, and showed no persistent cognitive impairment. Reactive oxygen species have been reported to mediate neurological injury in CM. Increased production of malondialdehyde (MDA) and conjugated dienes was detected in the brains of PbA-infected C57BL/6 mice with CM, indicating high oxidative stress. Treatment of PbA-infected C57BL/6 mice with additive antioxidants together with chloroquine at the first signs of CM prevented the development of persistent cognitive damage. These studies provide new insights into the natural history of cognitive dysfunction after rescue therapy for CM that may have clinical relevance, and may also be relevant to cerebral sequelae of sepsis and other disorders.
Output:
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Cerebral malaria (CM) is a deadly consequence of Plasmodium falciparum infection. Severe neurologic deficits are frequent during CM. Although most resolve within 6 months, several retrospective studies have described high frequencies of long-lasting cognitive impairment after an episode of CM. We developed behavioral tests to identify cognitive impairment due to experimental CM. During infection with Plasmodium berghei ANKA (PbA), mice susceptible to CM (C57BL/6) developed long-lasting cognitive impairment in contextual and aversive memory. The same profile was seen in Swiss Webster mice infected with Plasmodium yoelii XL, a lethal strain that also induces neurological dysfunctions in susceptible mice strains, confirming that the cognitive dysfunction is closely associated to the development of CM. Reactive oxygen species are described as mediators of neurological and cognitive impairment associated to sepsis and Alzheimer's disease. Here we found enhanced production of malondialdeyde and conjugated dienes in brains of PbA-infected C57BL/6 mice, indicating oxidative stress. Antioxidant therapy with N-acetylcisteine and desferroxamine, as an additive to chloroquine, prevented the cognitive impairment, confirming the importance of oxidative stress in CM-associated cognitive sequellae. Administration of additive antioxidants may be a successful therapeutic strategy to control long-lasting consequences of CM and in other severe systemic inflammatory syndromes with neurological involvement.
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PLOS36
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Leishmania (L.) killicki (syn. L. tropica), which causes cutaneous leishmaniasis in Maghreb, was recently described in this region and identified as a subpopulation of L. tropica. The present genetic analysis was conducted to explore the spatio-temporal distribution of L. killicki (syn. L. tropica) and its transmission dynamics. To better understand the evolution of this parasite, its population structure was then compared with that of L. tropica populations from Morocco. In total 198 samples including 85 L. killicki (syn. L. tropica) (from Tunisia, Algeria and Libya) and 113 L. tropica specimens (all from Morocco) were tested. Theses samples were composed of 168 Leishmania strains isolated from human skin lesions, 27 DNA samples from human skin lesion biopsies, two DNA samples from Ctenodactylus gundi bone marrow and one DNA sample from a Phlebotomus sergenti female. The sample was analyzed by using MultiLocus Enzyme Electrophoresis (MLEE) and MultiLocus Microsatellite Typing (MLMT) approaches. Analysis of the MLMT data support the hypothesis that L. killicki (syn. L. tropica) belongs to the L. tropica complex, despite its strong genetic differentiation, and that it emerged from this taxon by a founder effect. Moreover, it revealed a strong structuring in L. killicki (syn. L. tropica) between Tunisia and Algeria and within the different Tunisian regions, suggesting low dispersion of L. killicki (syn. L. tropica) in space and time. Comparison of the L. tropica (exclusively from Morocco) and L. killicki (syn. L. tropica) population structures revealed distinct genetic organizations, reflecting different epidemiological cycles.
Output:
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Leishmania killicki (syn. L. tropica) was discovered in 1986. Few studies have been conducted on this parasite exclusively described in Maghreb. Consequently, many elements on its epidemiology, transmission, population structure and dynamics remain unknown.
To better understand the evolution of this parasite, its population structure has been compared with that of L. tropica populations from Morocco using Multilocus Enzyme Electrophoresis (MLEE) and MultiLocus Microsatellite Typing (MLMT) typing. MLMT data support the hypothesis that L. killicki (syn. L. tropica) belongs to the L. tropica complex despite the strong genetic differentiation between them. Despite the probable recent divergence between L. killicki (syn. L. tropica) and L. tropica, they seem to evolve differently. Indeed, L. killicki (syn. L. tropica) appears slightly polymorphic and highly structured in space and time, while L. tropica was genetically heterogeneous, slightly structured geographically and temporally. The different population structures revealed distinct genetic organizations, reflecting different epidemiological cycles. Several parameters could explain these opposite epidemiological and genetic patterns such as ecosystems, vectors and reservoirs.
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PLOS37
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Genome engineering is a powerful approach to study how chromosomal architecture impacts phenotypes. However, quantifying the fitness impact of translocations independently from the confounding effect of base substitutions has so far remained challenging. We report a novel application of the CRISPR/Cas9 technology allowing to generate with high efficiency both uniquely targeted and multiple concomitant reciprocal translocations in the yeast genome. Targeted translocations are constructed by inducing two double-strand breaks on different chromosomes and forcing the trans-chromosomal repair through homologous recombination by chimerical donor DNAs. Multiple translocations are generated from the induction of several DSBs in LTR repeated sequences and promoting repair using endogenous uncut LTR copies as template. All engineered translocations are markerless and scarless. Targeted translocations are produced at base pair resolution and can be sequentially generated one after the other. Multiple translocations result in a large diversity of karyotypes and are associated in many instances with the formation of unanticipated segmental duplications. To test the phenotypic impact of translocations, we first recapitulated in a lab strain the SSU1/ECM34 translocation providing increased sulphite resistance to wine isolates. Surprisingly, the same translocation in a laboratory strain resulted in decreased sulphite resistance. However, adding the repeated sequences that are present in the SSU1 promoter of the resistant wine strain induced sulphite resistance in the lab strain, yet to a lower level than that of the wine isolate, implying that additional polymorphisms also contribute to the phenotype. These findings illustrate the advantage brought by our technique to untangle the phenotypic impacts of structural variations from confounding effects of base substitutions. Secondly, we showed that strains with multiple translocations, even those devoid of unanticipated segmental duplications, display large phenotypic diversity in a wide range of environmental conditions, showing that simply reconfiguring chromosome architecture is sufficient to provide fitness advantages in stressful growth conditions.
Output:
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Chromosomes are highly dynamic objects that often undergo large structural variations such as reciprocal translocations. Such rearrangements can have dramatic functional consequences, as they can disrupt genes, change their regulation or create novel fusion genes at their breakpoints. For instance, 90–95% of patients diagnosed with chronic myeloid leukemia carry the Philadelphia chromosome characterized by a reciprocal translocation between chromosomes 9 and 22. In addition, translocations reorganize the genetic information along chromosomes, which in turn can modify the 3D architecture of the genome and potentially affect its functioning. Quantifying the fitness impact of translocations independently from the confounding effect of base substitutions has so far remained challenging. Here, we report a novel CRISPR/Cas9-based technology allowing to generate with high efficiency and at a base-pair precision either uniquely targeted or multiple reciprocal translocations in yeast, without leaving any marker or scar in the genome. Engineering targeted reciprocal translocations allowed us for the first time to untangle the phenotypic impacts of large chromosomal rearrangements from that of point mutations. In addition, the generation of multiple translocations led to a large reorganization of the genetic information along the chromosomes, often including unanticipated large segmental duplications. We showed that reshuffling the genome resulted in the emergence of fitness advantage in stressful environmental conditions, even in strains where no gene was disrupted or amplified by the translocations.
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PLOS38
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Systematic identification of protein-drug interaction networks is crucial to correlate complex modes of drug action to clinical indications. We introduce a novel computational strategy to identify protein-ligand binding profiles on a genome-wide scale and apply it to elucidating the molecular mechanisms associated with the adverse drug effects of Cholesteryl Ester Transfer Protein (CETP) inhibitors. CETP inhibitors are a new class of preventive therapies for the treatment of cardiovascular disease. However, clinical studies indicated that one CETP inhibitor, Torcetrapib, has deadly off-target effects as a result of hypertension, and hence it has been withdrawn from phase III clinical trials. We have identified a panel of off-targets for Torcetrapib and other CETP inhibitors from the human structural genome and map those targets to biological pathways via the literature. The predicted protein-ligand network is consistent with experimental results from multiple sources and reveals that the side-effect of CETP inhibitors is modulated through the combinatorial control of multiple interconnected pathways. Given that combinatorial control is a common phenomenon observed in many biological processes, our findings suggest that adverse drug effects might be minimized by fine-tuning multiple off-target interactions using single or multiple therapies. This work extends the scope of chemogenomics approaches and exemplifies the role that systems biology has in the future of drug discovery.
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Both the cost to launch a new drug and the attrition rate during the late stage of the drug discovery and development process are increasing. Torcetrapib is a case in point, having been withdrawn from phase III clinical trials after 15 years of development and an estimated cost of US $800 M. Torcetrapib represents a new class of therapies for the treatment of cardiovascular disease; however, clinical studies indicated that Torcetrapib has deadly side-effects as a result of hypertension. To understand the origins of these adverse drug reactions from Torcetrapib and other related drugs undergoing clinical trials, we introduce a systematic strategy to identify off-targets in the human structural proteome and investigate the roles of these off-targets in impacting human physiology and pathology using biochemical pathway analysis. Our findings suggest that potential side-effects of a new drug can be identified at an early stage of the development cycle and be minimized by fine-tuning multiple off-target interactions. The hope is that this can reduce both the cost of drug development and the mortality rates during clinical trials.
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PLOS39
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The Global Programme to Eliminate Lymphatic Filariasis (LF) aims to eliminate the disease as a public health problem by 2020 by conducting mass drug administration (MDA) and controlling morbidity. Once elimination targets have been reached, surveillance is critical for ensuring that programmatic gains are sustained, and challenges include timely identification of residual areas of transmission. WHO guidelines encourage cost-efficient surveillance, such as integration with other population-based surveys. In American Samoa, where LF is caused by Wuchereria bancrofti, and Aedes polynesiensis is the main vector, the LF elimination program has made significant progress. Seven rounds of MDA (albendazole and diethycarbamazine) were completed from 2000 to 2006, and Transmission Assessment Surveys were passed in 2010/2011 and 2015. However, a seroprevalence study using an adult serum bank collected in 2010 detected two potential residual foci of transmission, with Og4C3 antigen (Ag) prevalence of 30.8% and 15.6%. We conducted a follow up study in 2014 to verify if transmission was truly occurring by comparing seroprevalence between residents of suspected hotspots and residents of other villages. In adults from non-hotspot villages (N = 602), seroprevalence of Ag (ICT or Og4C3), Bm14 antibody (Ab) and Wb123 Ab were 1.2% (95% CI 0.6–2.6%), 9.6% (95% CI 7.5%-12.3%), and 10.5% (95% CI 7.6–14.3%), respectively. Comparatively, adult residents of Fagali’i (N = 38) had significantly higher seroprevalence of Ag (26.9%, 95% CI 17.3–39.4%), Bm14 Ab (43.4%, 95% CI 32.4–55.0%), and Wb123 Ab 55.2% (95% CI 39.6–69.8%). Adult residents of Ili’ili/Vaitogi/Futiga (N = 113) also had higher prevalence of Ag and Ab, but differences were not statistically significant. The presence of transmission was demonstrated by 1.1% Ag prevalence (95% CI 0.2% to 3.1%) in 283 children aged 7–13 years who lived in one of the suspected hotspots; and microfilaraemia in four individuals, all of whom lived in the suspected hotspots, including a 9 year old child. Our results provide field evidence that integrating LF surveillance with other surveys is effective and feasible for identifying potential hotspots, and conducting surveillance at worksites provides an efficient method of sampling large populations of adults.
Output:
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Lymphatic filariasis (LF) is caused by infection with filarial worms that are transmitted by mosquito bites. The Global Programme to Eliminate Lymphatic Filariasis aims to eliminate the disease as a public health problem by 2020. Once elimination targets have been reached, cost-effective surveillance strategies are required to ensure that any areas of ongoing transmission or resurgence are quickly identified and managed. Potential options include the integration of LF surveillance with other public health activities. In American Samoa, blood samples collected in 2010 for a research project on a different disease (leptospirosis) were used to test for evidence of LF infection, and the study found two possible areas of ongoing transmission. We conducted a follow up study in 2014 to verify whether LF infection was truly occurring in these two areas, and found that infection rates in both areas were significantly higher compared to other parts of American Samoa. Our results therefore provide field evidence that integrating LF surveillance activities with other population-based surveys are potentially effective and feasible, and provide a cost-effective method for identifying residual areas of transmission.
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PLOS40
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The circadian oscillator is a molecular feedback circuit whose orchestration involves posttranslational control of the activity and protein levels of its components. Although controlled proteolysis of circadian proteins is critical for oscillator function, our understanding of the underlying mechanisms remains incomplete. Here, we report that JmjC domain–containing protein 5 (JMJD5) interacts with CRYPTOCHROME 1 (CRY1) in an F-box/leucine-rich repeat protein 3 (FBXL3)-dependent manner and facilitates targeting of CRY1 to the proteasome. Genetic deletion of JMJD5 results in greater CRY1 stability, reduced CRY1 association with the proteasome, and disruption of circadian gene expression. We also report that in the absence of JMJD5, AMP-regulated protein kinase (AMPK)-induced CRY1 degradation is impaired, establishing JMJD5 as a key player in this mechanism. JMJD5 cooperates with CRY1 to repress circadian locomotor output cycles protein kaput (CLOCK)–brain and muscle ARNT-like protein 1 (BMAL1), thus linking CRY1 destabilization to repressive function. Finally, we find that ablation of JMJD5 impacts FBXL3- and CRY1-related functions beyond the oscillator.
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In mammals, circadian rhythms are generated by a molecular oscillator in which the circadian locomotor output cycles protein kaput (CLOCK)–brain and muscle ARNT-like protein 1 (BMAL1) transcription factors drive expression of the genes coding for their own repressors, the CRYPTOCHROME (CRY) and PERIOD (PER) proteins. A key feature of the oscillator is that the protein stability of its components is highly regulated. Previous studies had implicated the JmjC domain–containing protein 5 (JMJD5) in regulation of the circadian clock in plants and flies. Here, we show that cells and livers that lack JMJD5 exhibit dysregulation of circadian gene expression. Mechanistically, JMJD5 is required for CRY1 degradation, including its destabilization by AMP-regulated protein kinase (AMPK), by facilitating its interaction with the proteasome. We found that JMJD5 is needed for normal CRY1-mediated transcriptional repression, thereby uncovering an inverse relationship between CRY1 stability and circadian repression. Finally, we showed that JMJD5 impinges on non-clock roles of F-box/leucine-rich repeat protein 3 (FBXL3) and CRY1. Altogether, our studies demonstrate that JMJD5 is a novel link between the oscillator and other physiological processes.
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PLOS41
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The innate immune response provides the first line of defense against viruses and other pathogens by responding to specific microbial molecules. Influenza A virus (IAV) produces double-stranded RNA as an intermediate during the replication life cycle, which activates the intracellular pathogen recognition receptor RIG-I and induces the production of proinflammatory cytokines and antiviral interferon. Understanding the mechanisms that regulate innate immune responses to IAV and other viruses is of key importance to develop novel therapeutic strategies. Here we used myeloid cell specific A20 knockout mice to examine the role of the ubiquitin-editing protein A20 in the response of myeloid cells to IAV infection. A20 deficient macrophages were hyperresponsive to double stranded RNA and IAV infection, as illustrated by enhanced NF-κB and IRF3 activation, concomitant with increased production of proinflammatory cytokines, chemokines and type I interferon. In vivo this was associated with an increased number of alveolar macrophages and neutrophils in the lungs of IAV infected mice. Surprisingly, myeloid cell specific A20 knockout mice are protected against lethal IAV infection. These results challenge the general belief that an excessive host proinflammatory response is associated with IAV-induced lethality, and suggest that under certain conditions inhibition of A20 might be of interest in the management of IAV infections.
Output:
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Influenza virus or flu epidemics represent a recurrent threat to the public health, especially for individuals which are part of a high-risk group such as children, elderly or immune-compromised people. Sporadic pandemic flu outbreaks, such as the Spanish flu of 1918, may cause high grades of mortality among healthy persons. A better understanding of how the immune system deals with these pathogens is of key importance. The protein A20 is an important negative regulator of both innate and adaptive immune responses. We show that the specific deletion of A20 in myeloid cells, such as macrophages and neutrophils, improves the resistance against otherwise lethal influenza infections. This protective effect is mediated by an enhanced innate immune response following respiratory challenge with influenza virus. Although exaggerated pulmonary immune responses are believed to be the primary cause of often life threatening influenza virus induced pneumonia, we demonstrate that boosting the innate immune response by selectively targeting the functionality of A20 in myeloid cells is beneficial for the host survival. This finding provides us with a novel valuable approach for treating influenza and potentially other respiratory viral infections.
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PLOS42
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Melioidosis is an often fatal infectious disease affecting humans and animals in tropical regions and is caused by the saprophytic environmental bacterium Burkholderia pseudomallei. Domestic gardens are not only a common source of exposure to soil and thus to B. pseudomallei, but they also have been found to contain more B. pseudomallei than other environments. In this study we addressed whether anthropogenic manipulations common to gardens such as irrigation or fertilizers change the occurrence of B. pseudomallei. We conducted a soil microcosm experiment with a range of fertilizers and soil types as well as a longitudinal interventional study over three years on an experimental fertilized field site in an area naturally positive for B. pseudomallei. Irrigation was the only consistent treatment to increase B. pseudomallei occurrence over time. The effects of fertilizers upon these bacteria depended on soil texture, physicochemical soil properties and biotic factors. Nitrates and urea increased B. pseudomallei load in sand while phosphates had a positive effect in clay. The high buffering and cation exchange capacities of organic material found in a commercial potting mix led to a marked increase in soil salinity with no survival of B. pseudomallei after four weeks in the potting mix sampled. Imported grasses were also associated with B. pseudomallei occurrence in a multivariate model. With increasing population density in endemic areas these findings inform the identification of areas in the anthropogenic environment with increased risk of exposure to B. pseudomallei.
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Melioidosis cases are on the rise in endemic areas of northern Australia and Thailand. This potentially severe infectious disease affecting humans and animals in the tropical belt is caused by the gram negative bacterium Burkholderia pseudomallei. Domestic gardens are a common point of exposure to these environmental bacteria and B. pseudomallei are more prevalent in the dry season in gardens when compared to other areas. This is why we analysed whether common gardening practices such as regular watering (irrigation) or soil fertilizing change the occurrence of B. pseudomallei. We conducted a soil microcosm experiment with a range of fertilizers and soil types as well as a longitudinal interventional study over three years on an experimental fertilized field site in an area naturally positive for B. pseudomallei. Irrigation was the only consistent treatment to increase B. pseudomallei occurrence over time. The effects of fertilizers upon these bacteria depended on soil texture, physicochemical properties such as pH or salinity and vegetation. B. pseudomallei occurrence was also associated with imported grasses. With increasing populations in endemic areas, these findings inform the identification of areas in the anthropogenic environment with increased risk of exposure to B. pseudomallei.
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PLOS43
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Reporting bias in the literature occurs when there is selective revealing or suppression of results, influenced by the direction of findings. We assessed the risk of reporting bias in the epidemiological literature on health-related behavior (tobacco, alcohol, diet, physical activity, and sedentary behavior) and cardiovascular disease mortality and all-cause mortality and provided a comparative assessment of reporting bias between health-related behavior and statin (in primary prevention) meta-analyses. We searched Medline, Embase, Cochrane Methodology Register Database, and Web of Science for systematic reviews synthesizing the associations of health-related behavior and statins with cardiovascular disease mortality and all-cause mortality published between 2010 and 2016. Risk of bias in systematic reviews was assessed using the ROBIS tool. Reporting bias in the literature was evaluated via small-study effect and excess significance tests. We included 49 systematic reviews in our study. The majority of these reviews exhibited a high overall risk of bias, with a higher extent in health-related behavior reviews, relative to statins. We reperformed 111 meta-analyses conducted across these reviews, of which 65% had statistically significant results (P < 0.05). Around 22% of health-related behavior meta-analyses showed small-study effect, as compared to none of statin meta-analyses. Physical activity and the smoking research areas had more than 40% of meta-analyses with small-study effect. We found evidence of excess significance in 26% of health-related behavior meta-analyses, as compared to none of statin meta-analyses. Half of the meta-analyses from physical activity, 26% from diet, 18% from sedentary behavior, 14% for smoking, and 12% from alcohol showed evidence of excess significance bias. These biases may be distorting the body of evidence available by providing inaccurate estimates of preventive effects on cardiovascular and all-cause mortality.
Output:
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In the scientific literature, reporting bias occurs when communication and publication of results are influenced by the direction of findings. Reporting bias can distort scientific evidence and may misguide subsequent clinical and public health efforts. Our study provided an assessment of the degree of reporting bias in the literature on health-related behavior (smoking, alcohol, diet, physical activity, and sedentary behavior) and statins and their association with cardiovascular disease and mortality. We analyzed recently published systematic reviews. Most of the systematic reviews (90%) had a high risk of bias related to study eligibility criteria, identification and selection of studies, data collection and study appraisal, and synthesis and findings. We found evidence of reporting bias in about one-fifth of health-related behavior meta-analyses but none of the statin-related meta-analyses. Readers should be aware of the extent of reporting bias in these research areas when interpreting meta-analytical results.
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PLOS44
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Eukaryotic cells integrate layers of gene regulation to coordinate complex cellular processes; however, mechanisms of post-transcriptional gene regulation remain poorly studied. The human fungal pathogen Histoplasma capsulatum (Hc) responds to environmental or host temperature by initiating unique transcriptional programs to specify multicellular (hyphae) or unicellular (yeast) developmental states that function in infectivity or pathogenesis, respectively. Here we used recent advances in next-generation sequencing to uncover a novel re-programming of transcript length between Hc developmental cell types. We found that ~2% percent of Hc transcripts exhibit 5’ leader sequences that differ markedly in length between morphogenetic states. Ribosome density and mRNA abundance measurements of differential leader transcripts revealed nuanced transcriptional and translational regulation. One such class of regulated longer leader transcripts exhibited tight transcriptional and translational repression. Further examination of these dually repressed genes revealed that some control Hc morphology and that their strict regulation is necessary for the pathogen to make appropriate developmental decisions in response to temperature.
Output:
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Eukaryotic cells alter their developmental programs in response to environmental signals. Histoplasma capsulatum (Hc), a ubiquitous fungal pathogen of humans, establishes unique transcriptional programs to specify growth in either a multicellular hyphal form or unicellular yeast form in response to temperature. Since hyphae and yeast are specialized to function in infectivity or pathogenesis, respectively, Hc provides a clinically relevant system in which to query eukaryotic regulatory processes. Here we used next-generation sequencing approaches to annotate the transcriptomes of four distinct Hc strains in response to temperature. We found that a fraction of Hc transcripts have differential transcript architecture in hyphae and yeast, exhibiting 5’ leader sequences that differ markedly in length between morphogenetic states. To begin to understand the effect of these differential leader sequences on expression, we performed the first ribosome density and mRNA abundance measurements in Hc, thereby uncovering transcriptional and translational control that contribute to cell-type regulation.
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PLOS45
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Leishmania is a protozoan parasite that alternates its life cycle between the sand-fly vector and the mammalian host. This alternation involves environmental changes and leads the parasite to dynamic modifications in morphology, metabolism, cellular signaling and regulation of gene expression to allow for a rapid adaptation to new conditions. The L-arginine pathway in L. amazonensis is important during the parasite life cycle and interferes in the establishment and maintenance of the infection in mammalian macrophages. Host arginase is an immune-regulatory enzyme that can reduce the production of nitric oxide by activated macrophages, directing the availability of L-arginine to the polyamine pathway, resulting in parasite replication. In this work, we performed transcriptional profiling to identify differentially expressed genes in L. amazonensis wild-type (La-WT) versus L. amazonensis arginase knockout (La-arg-) promastigotes and axenic amastigotes.
A total of 8253 transcripts were identified in La-WT and La-arg- promastigotes and axenic amastigotes, about 60% of them codifying hypothetical proteins and 443 novel transcripts, which did not match any previously annotated genes. Our RNA-seq data revealed that 85% of genes were constitutively expressed. The comparison of transcriptome and metabolome data showed lower levels of arginase and higher levels of glutamate-5-kinase in La-WT axenic amastigotes compared to promastigotes. The absence of arginase activity in promastigotes increased the levels of pyrroline 5-carboxylate reductase, but decreased the levels of arginosuccinate synthase, pyrroline 5-carboxylate dehydrogenase, acetylornithine deacetylase and spermidine synthase transcripts levels. These observations can explain previous metabolomic data pointing to the increase of L-arginine, citrulline and L-glutamate and reduction of aspartate, proline, ornithine and putrescine. Altogether, these results indicate that arginase activity is important in Leishmania gene expression modulation during differentiation and adaptation to environmental changes. Here, we confirmed this hypothesis with the identification of differential gene expression of the enzymes involved in biosynthesis of amino acids, arginine and proline metabolism and arginine biosynthesis.
All data provided information about the transcriptomic profiling and the expression levels of La-WT and La-arg- promastigotes and axenic amastigotes. These findings revealed the importance of arginase in parasite survival and differentiation, and indicated the existence of a coordinated response in the absence of arginase activity related to arginine and polyamine pathways.
Output:
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Leishmania are auxotrophic for many essential nutrients, including amino acids. In this way, the parasite needs to uptake the amino acids from the environment. The uptake of amino acids is mediated by amino acid transporters that are unique for Leishmania. As part of polyamine pathway, the arginase converts L-arginine to ornithine and furthermore to putrescine, products which are essential for parasite growth. On the other hand, the absence of arginase activity could alter the metabolism of the parasite to surpass the external signals during the life cycle and the fate of infection. The transcriptional profiling of La-WT and La-arg- promastigotes and axenic amastigotes revealed 8253 transcripts, 60% encoding hypothetical proteins and 443 novel transcripts. In addition, our data revealed that 85% of the genes were constitutively expressed. Among the 15% (1268 genes) of the differentially expressed genes, we identified genes up- and down-regulated comparing the transcript abundance from different life cycle stages of the parasite and in the presence or absence of arginase. We also combined the transcriptional with metabolic profile that revealed a proportional correlation between enzyme and metabolites in the polyamine pathway. The differentiation of promastigotes to amastigotes alters the expression of enzymes from polyamines biosynthesis, which modulates ornithine, L-glutamate, proline and putrescine levels. In addition, the absence of arginase activity increased the levels of L-arginine, citrulline and L-glutamate and decreased the levels of aspartate, proline, ornithine and putrescine in promastigotes by differential modulation of genes involved in its metabolism. Altogether these data provided additional insights into how Leishmania is able to modulate its biological functions in the presence or absence of arginase activity to survive during environmental changes.
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PLOS46
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Dengue is one of the most significant public health problems in tropical and subtropical countries, and is increasingly being detected in traditionally non-endemic areas. In Bhutan, dengue virus (DENV) has only recently been detected and limited information is available. In this study, we analyzed the epidemiological and molecular characteristics of DENV in two southern districts in Bhutan from 2013–2014. During this period, 379 patients were clinically diagnosed with suspected dengue, of whom 119 (31.4%) were positive for DENV infection by NS1 ELISA and/or nested RT-PCR. DENV serotypes 1, 2 and 3 were detected with DENV-1 being predominant. Phylogenetic analysis of DENV-1 using envelope gene demonstrated genotype V, closely related to strains from northern India.
Output:
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We describe the epidemiological and molecular features of DENV currently circulating in the two southwestern districts of Bhutan, demonstrating a shift in serotype dominance from previous DENV-3 (2004–2006) to current DENV-1 (2013–2014). The presence of the dengue virus in Bhutan is a relatively recent one. Unfortunately, dengue epidemiological and molecular data in this country is scarce. A fever outbreak in 2013 and 2014 saw patients seeking care at medical facilities in two district of southwestern Bhutan bordering with India. Analyses of serum specimens collected from these patients indicated that dengue virus was at least a major source of this outbreak. These specimens were analyzed in the Public Health Laboratory in Bhutan and in AFRIMS, Thailand. With a combination of three different assays, we established that 31% of all cases captured were caused by dengue virus, although the proportion was higher in 2013 than in 2014. Three different serotypes of dengue virus were found: DENV-1, -2 and -3. No DENV-4 was found. We successfully isolated DENV-1, from which was sequenced the E gene for further analyses. Our analyses revealed that the current DENV-1 in Bhutan probably originated from India.
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PLOS47
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Homeostatic proliferation ensures the longevity of central memory T-cells by inducing cell proliferation in the absence of cellular differentiation or activation. This process is governed mainly by IL-7. Central memory T-cells can also be stimulated via engagement of the T-cell receptor, leading to cell proliferation but also activation and differentiation. Using an in vitro model of HIV-1 latency, we have examined in detail the effects of homeostatic proliferation on latently infected central memory T cells. We have also used antigenic stimulation via anti-CD3/anti-CD28 antibodies and established a comparison with a homeostatic proliferation stimulus, to evaluate potential differences in how either treatment affects the dynamics of latent virus populations. First, we show that homeostatic proliferation, as induced by a combination of IL-2 plus IL-7, leads to partial reactivation of latent HIV-1 but is unable to reduce the size of the reservoir in vitro. Second, latently infected cells are able to homeostatically proliferate in the absence of viral reactivation or cell differentiation. These results indicate that IL-2 plus IL-7 may induce a detrimental effect by favoring the maintenance of the latent HIV-1 reservoir. On the other hand, antigenic stimulation efficiently reactivated latent HIV-1 in cultured central memory cells and led to depletion of the latently infected cells via virus-induced cell death.
Output:
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HIV-1 latently infected cells are considered the last barrier towards viral eradication and cure. However, the low number of latently infected cells found in patients makes studies extremely difficult. Here, using a model of primary CD4 T-cells we study the behavior of latently infected central memory T cells when undergoing homeostatic proliferation. Homeostatic proliferation ensures the longevity of the central memory population, as it does not involve cellular differentiation. In the context of HIV infection, IL-7 has been reported to induce viral outgrowth from latently infected cells in different cellular models. However, those studies did not examine the relationship between cell proliferation and viral reactivation. We here report that the strong effect of IL-7 on the proliferation of memory cells counteracts this cytokine's modest ability to purge latent viruses. Thus, central memory cells are subject to homeostatic proliferation, a physiological effect that may contribute to the longevity of the latent reservoir in HIV-1 infected patients.
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PLOS48
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The cellular response to DNA double-strand breaks (DSBs) is initiated by the MRX/MRN complex (Mre11-Rad50-Xrs2 in yeast; Mre11-Rad50-Nbs1 in mammals), which recruits the checkpoint kinase Tel1/ATM to DSBs. In Saccharomyces cerevisiae, the role of Tel1 at DSBs remains enigmatic, as tel1Δ cells do not show obvious hypersensitivity to DSB-inducing agents. By performing a synthetic phenotype screen, we isolated a rad50-V1269M allele that sensitizes tel1Δ cells to genotoxic agents. The MRV1269MX complex associates poorly to DNA ends, and its retention at DSBs is further reduced by the lack of Tel1. As a consequence, tel1Δ rad50-V1269M cells are severely defective both in keeping the DSB ends tethered to each other and in repairing a DSB by either homologous recombination (HR) or nonhomologous end joining (NHEJ). These data indicate that Tel1 promotes MRX retention to DSBs and this function is important to allow proper MRX-DNA binding that is needed for end-tethering and DSB repair. The role of Tel1 in promoting MRX accumulation to DSBs is counteracted by Rif2, which is recruited to DSBs. We also found that Rif2 enhances ATP hydrolysis by MRX and attenuates MRX function in end-tethering, suggesting that Rif2 can regulate MRX activity at DSBs by modulating ATP-dependent conformational changes of Rad50.
Output:
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Many tumors contain mutations that confer defects in repairing DNA double-strand breaks (DSBs). In both yeast and mammals, the MRX/MRN complex (Mre11-Rad50-Xrs2 in yeast; Mre11-Rad50-Nbs1 in mammals) plays critical functions in repairing a DSB by either nonhomologous end joining (NHEJ) or homologous recombination (HR). Furthermore, it recruits the checkpoint kinase Tel1/ATM. Although ATM is considered to be a tumor suppressor, up-regulation of ATM signaling promotes chemoresistance, radioresistance and metastasis. For this reason, cancer therapies targeting ATM have been developed to increase the effectiveness of standard genotoxic treatments and/or to set up synthetic lethal approaches in cancers with DNA repair defects. We aimed to identify the precise role of ATM/Tel1 in these processes. By performing a synthetic phenotype screen, we identified a mutation (rad50-V1269M) altering the Rad50 subunit of the MRX complex, which sensitizes cells lacking Tel1 to genotoxic agents. Genetic and biochemical characterization of MRV1269MX protein complex revealed that Tel1 promotes MRX association at DSBs to allow proper MRX-DNA binding that is needed for DSB repair. The role of Tel1 in promoting MRX retention on DSBs is counteracted by Rif2, which can regulate MRX activity at DSBs by modulating ATP-dependent conformational changes in Rad50. Our finding that MRX dysfunctions can be synthetically lethal with Tel1 loss in the presence of genotoxic agents suggests that ATM inhibitors could be beneficial in patients whose tumors have defective MRN functions.
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PLOS49
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: For Chagas disease, the most serious infectious disease in the Americas, effective disease control depends on elimination of vectors through spraying with insecticides. Molecular genetic research can help vector control programs by identifying and characterizing vector populations and then developing effective intervention strategies.
The population genetic structure of Triatoma infestans (Hemiptera: Reduviidae), the main vector of Chagas disease in Bolivia, was investigated using a hierarchical sampling strategy. A total of 230 adults and nymphs from 23 localities throughout the department of Chuquisaca in Southern Bolivia were analyzed at ten microsatellite loci. Population structure, estimated using analysis of molecular variance (AMOVA) to estimate FST (infinite alleles model) and RST (stepwise mutation model), was significant between western and eastern regions within Chuquisaca and between insects collected in domestic and peri-domestic habitats. Genetic differentiation at three different hierarchical geographic levels was significant, even in the case of adjacent households within a single locality (RST = 0.14, FST = 0.07). On the largest geographic scale, among five communities up to 100 km apart, RST = 0.12 and FST = 0.06. Cluster analysis combined with assignment tests identified five clusters within the five communities.
Some houses are colonized by insects from several genetic clusters after spraying, whereas other households are colonized predominately by insects from a single cluster. Significant population structure, measured by both RST and FST, supports the hypothesis of poor dispersal ability and/or reduced migration of T. infestans. The high degree of genetic structure at small geographic scales, inferences from cluster analysis and assignment tests, and demographic data suggest reinfesting vectors are coming from nearby and from recrudescence (hatching of eggs that were laid before insecticide spraying). Suggestions for using these results in vector control strategies are made.
Output:
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Chagas disease is a protozoan infection caused by the parasite Trypanosoma cruzi. Chagas is prevalent throughout Central and South America, and it remains a chief concern in Bolivia. A movement that began in 1991 called the Southern Cone Initiative has been successful in reducing the incidence of Chagas disease in the Southern Cone countries of Argentina, Brazil, Chile, and Uruguay; but due to socio-economic and other factors, incidence remains high in Bolivia. The most important mode of transmission of T. cruzi to humans and other mammals is through feces of triatomine bugs. Thus, disease control and transmission prevention focus on elimination of triatomine vectors, and more specifically in Bolivia, it focuses on the elimination of Triatoma infestans. This study focuses on T. infestans in the Department of Chuquisaca, Bolivia. Ten highly variable microsatellite markers were used to analyze the population structure of insects collected in different towns. Statistical analyses show that T. infestans are highly structured, which means that they colonize on a small geographic scale. The results also suggest little active dispersal. These findings should be implemented during control efforts so that insecticide spraying focuses on geographic areas of colonization and re-colonization.
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PLOS50
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Recent advances in experimental techniques have allowed the simultaneous recordings of populations of hundreds of neurons, fostering a debate about the nature of the collective structure of population neural activity. Much of this debate has focused on the empirical findings of a phase transition in the parameter space of maximum entropy models describing the measured neural probability distributions, interpreting this phase transition to indicate a critical tuning of the neural code. Here, we instead focus on the possibility that this is a first-order phase transition which provides evidence that the real neural population is in a ‘structured’, collective state. We show that this collective state is robust to changes in stimulus ensemble and adaptive state. We find that the pattern of pairwise correlations between neurons has a strength that is well within the strongly correlated regime and does not require fine tuning, suggesting that this state is generic for populations of 100+ neurons. We find a clear correspondence between the emergence of a phase transition, and the emergence of attractor-like structure in the inferred energy landscape. A collective state in the neural population, in which neural activity patterns naturally form clusters, provides a consistent interpretation for our results.
Output:
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Neurons encoding the natural world are correlated in their activities. The structure of this correlation fundamentally changes the population code, and these effects increase in larger neural populations. We experimentally recorded from populations of 100+ retinal ganglion cells and probed the structure of their joint probability distribution with a series of analytical tools inspired by statistical physics. We found a robust ‘collective state’ in the neural population that resembles the low temperature state of a disordered magnet. This state generically emerges at sufficient correlation strength, where the energy landscape develops an attractor-like structure that naturally clusters neural activity.
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PLOS51
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The live attenuated Japanese encephalitis (JE) vaccine SA14-14-2 has been used in Nepal for catch-up campaigns and is now included in the routine immunisation schedule. Previous studies have shown good vaccine efficacy after one dose in districts with a high incidence of JE. The first well-documented dengue outbreak occurred in Nepal in 2006 with ongoing cases now thought to be secondary to migration from India. Previous infection with dengue virus (DENV) partially protects against JE and might also influence serum neutralising antibody titres against JEV. This study aimed to determine whether serum anti-JEV neutralisation titres are: 1. maintained over time since vaccination, 2. vary with historic local JE incidence, and 3. are associated with DENV neutralising antibody levels. We conducted a cross-sectional study in three districts of Nepal: Banke, Rupandehi and Udayapur. Udayapur district had been vaccinated against JE most recently (2009), but had been the focus of only one campaign, compared with two in Banke and three in Rupandehi. Participants answered a short questionnaire and serum was assayed for anti-JEV and anti-DENV IgM and IgG (by ELISA) and 50% plaque reduction neutralisation titres (PRNT50) against JEV and DENV serotypes 1–4. A titre of ≥1:10 was considered seropositive to the respective virus. JEV neutralising antibody seroprevalence (PRNT50 ≥ 1:10) was 81% in Banke and Rupandehi, but only 41% in Udayapur, despite this district being vaccinated more recently. Sensitivity of ELISA for both anti-JEV and anti-DENV antibodies was low compared with PRNT50. DENV neutralising antibody correlated with the JEV PRNT50 ≥1:10, though the effect was modest. IgM (indicating recent infection) against both viruses was detected in a small number of participants. We also show that DENV IgM is present in Nepali subjects who have not travelled to India, suggesting that DENV may have become established in Nepal. We therefore propose that further JE vaccine campaigns should be considered in Udayapur district, and similar areas that have had fewer vaccination campaigns.
Output:
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In Nepal, immunisation using a live attenuated vaccine is given against Japanese encephalitis (JE), caused by the mosquito-transmitted JE virus (JEV). JE immunisation has taken place via catch-up campaigns and is now part of the routine immunisation programme. Although previous studies have shown good vaccine efficacy in areas where there is a lot of natural exposure to the virus (high endemicity), it is suggested that the efficacy may wane in areas where transmission is lower. Dengue virus (DENV) belongs to the same family and genus as JEV. Previous infection with DENV may also influence the immune response to JEV. Therefore, we conducted a cross-sectional study in Nepal to measure immunity to JE, in districts of differing historic JE incidence, and time from JE vaccination. This showed that neutralising antibody to JEV was found more frequently in districts which had been the subject of more vaccination campaigns, rather than in the most recently vaccinated district. In addition, we cannot rule out a role for natural exposure to JEV in maintaining higher antibody levels. Additionally, the study showed that previous exposure to DENV was positively associated with an immune response to JEV, though this effect was modest. We conclude that there is a need to consider further JE vaccine catch up campaigns in some areas especially given that we could detect JEV IgM, indicating ongoing transmission. We show that ELISA yielded many false negative results for exposure to JEV or vaccination, when compared with neutralising antibody. We also identified some individuals during the course of the study with DENV IgM in their blood, but with no history of travel to India. This suggests that DENV may have become established in some areas of Nepal.
|
PLOS52
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Despite their importance in maintaining the integrity of all cellular pathways, the role of mutations on protein-protein interaction (PPI) interfaces as cancer drivers has not been systematically studied. Here we analyzed the mutation patterns of the PPI interfaces from 10,028 proteins in a pan-cancer cohort of 5,989 tumors from 23 projects of The Cancer Genome Atlas (TCGA) to find interfaces enriched in somatic missense mutations. To that end we use e-Driver, an algorithm to analyze the mutation distribution of specific protein functional regions. We identified 103 PPI interfaces enriched in somatic cancer mutations. 32 of these interfaces are found in proteins coded by known cancer driver genes. The remaining 71 interfaces are found in proteins that have not been previously identified as cancer drivers even that, in most cases, there is an extensive literature suggesting they play an important role in cancer. Finally, we integrate these findings with clinical information to show how tumors apparently driven by the same gene have different behaviors, including patient outcomes, depending on which specific interfaces are mutated.
Output:
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Until now, most efforts in cancer genomics have focused on identifying genes and pathways driving tumor development. Although this has been unquestionably a success, as evidenced by the fact that we now have an extensive catalogue of cancer driver genes and pathways, there is still a poor understanding of why patients with the same affected driver genes may have different disease outcomes or drug responses. This is precisely the aim of this work-to show how by considering proteins as multifunctional factories instead of monolithic black boxes, it is possible to identify novel cancer driver genes and propose molecular hypotheses to explain such heterogeneity. To that end we have mapped the mutation profiles of 5,989 cancer patients from TCGA to more than 10,000 protein structures, leading us to identify 103 protein interaction interfaces enriched in somatic mutations. Finally, we have integrated clinical annotations as well as proteomics data to show how tumors apparently driven by the same gene can display different behaviors, including patient outcomes, depending on which specific interfaces are mutated.
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PLOS53
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Alien species are a major component of human-induced environmental change. Variation in the numbers of alien species found in different areas is likely to depend on a combination of anthropogenic and environmental factors, with anthropogenic factors affecting the number of species introduced to new locations, and when, and environmental factors influencing how many species are able to persist there. However, global spatial and temporal variation in the drivers of alien introduction and species richness remain poorly understood. Here, we analyse an extensive new database of alien birds to explore what determines the global distribution of alien species richness for an entire taxonomic class. We demonstrate that the locations of origin and introduction of alien birds, and their identities, were initially driven largely by European (mainly British) colonialism. However, recent introductions are a wider phenomenon, involving more species and countries, and driven in part by increasing economic activity. We find that, globally, alien bird species richness is currently highest at midlatitudes and is strongly determined by anthropogenic effects, most notably the number of species introduced (i.e., “colonisation pressure”). Nevertheless, environmental drivers are also important, with native and alien species richness being strongly and consistently positively associated. Our results demonstrate that colonisation pressure is key to understanding alien species richness, show that areas of high native species richness are not resistant to colonisation by alien species at the global scale, and emphasise the likely ongoing threats to global environments from introductions of species.
Output:
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The introduction of alien species is one of the primary ways in which human actions are changing the environment. Alien species have been responsible for numerous global and local extinctions and are eroding the uniqueness of many natural environments. There is thus a basic need to understand which areas end up with more alien species. Here, we use a major new global database on the distribution of alien birds to show, first, how patterns in the number of species introduced to a location (colonisation pressure) have changed over time. We show that historical introductions were driven largely by European, and especially British, colonialism. However, the rate of bird introductions is increasing, with shifts in the locations of origin and introduction of species probably driven by the cage bird trade. We then combine information on where bird species have been introduced with a global map of alien bird species richness to identify the main drivers of richness. We show that colonisation pressure is the strongest predictor of alien bird species richness, but that there are other anthropogenic and environmental drivers. Most notably, once colonisation pressure has been accounted for, alien bird species richness is higher in areas where native bird species richness is higher.
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PLOS54
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The peritrophic matrix (PM) plays a key role in compartmentalization of the blood meal and as barrier to pathogens in many disease vectors. To establish an infection in sand flies, Leishmania must escape from the endoperitrophic space to prevent excretion with remnants of the blood meal digestion. In spite of the role played regarding Leishmania survival, little is known about sand fly PM molecular components and structural organization. We characterized three peritrophins (PpPer1, PpPer2, and PpPer3) from Phlebotomus papatasi. PpPer1 and PpPer2 display, respectively, four and one chitin-binding domains (CBDs). PpPer3 on the other hand has two CBDs, one mucin-like domain, and a putative domain with hallmarks of a CBD, but with changes in key amino acids. Temporal and spatial expression analyses show that PpPer1 is expressed specifically in the female midgut after blood feeding. PpPer2 and PpPer3 mRNAs were constitutively expressed in midgut and hindgut, with PpPer3 also being expressed in Malpighian tubules. PpPer2 was the only gene expressed in developmental stages. Interestingly, PpPer1 and PpPer3 expression are regulated by Le. major infection. Recombinant PpPer1, PpPer2 and PpPer3 were obtained and shown to display similar biochemical profiles as the native; we also show that PpPer1 and PpPer2 are able to bind chitin. Knockdown of PpPer1 led to a 44% reduction in protein, which in spite of producing an effect on the percentage of infected sand flies, resulted in a 39% increase of parasite load at 48 h. Our data suggest that PpPer1 is a component for the P. papatasi PM and likely involved in the PM role as barrier against Le. major infection.
Output:
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For a successful development within the midgut of the sand fly vector, Leishmania must overcome several barriers imposed by the vector that include the digestive proteases secreted within the midgut following a blood meal by the insect, the need to escape from the endoperitrophic space, and attachment to the midgut epithelia to prevent excretion with the remnants of the blood meal. The sand fly peritrophic matrix (PM) constitutes an important barrier against the establishment of Leishmania within the sand fly and if trapped within the PM these parasites will be passed along with the remnants of the blood meal. Despite the role of sand fly PM on Leishmania development, characterization of its molecular components and assessment of their roles against Leishmania are lacking. Thereby, we performed the molecular characterization of three P. papatasi peritrophins named PpPer1, PpPer2, and PpPer3. Overall, we demonstrated that: (1) PpPer3 displays a putative CBD domain that might have undertaken neo-functionalization, (2) PpPer1 and PpPer3 genes display differential gene expression upon Le. major infection; and (3) PpPer1 seems to be an important component for the function of P. papatasi PM as a barrier against Le. major infection.
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PLOS55
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Animal African trypanosomosis (AAT) is a neglected tropical disease which imposes a heavy burden on the livestock industry in Sub-Saharan Africa. Its causative agents are Trypanosoma parasites, with T. congolense and T. vivax being responsible for the majority of the cases. Recently, we identified a Nanobody (Nb474) that was employed to develop a homologous sandwich ELISA targeting T. congolense fructose-1,6-bisphosphate aldolase (TcoALD). Despite the high sequence identity between trypanosomatid aldolases, the Nb474-based immunoassay is highly specific for T. congolense detection. The results presented in this paper yield insights into the molecular principles underlying the assay’s high specificity.
The structure of the Nb474-TcoALD complex was determined via X-ray crystallography. Together with analytical gel filtration, the structure reveals that a single TcoALD tetramer contains four binding sites for Nb474. Through a comparison with the crystal structures of two other trypanosomatid aldolases, TcoALD residues Ala77 and Leu106 were identified as hot spots for specificity. Via ELISA and surface plasmon resonance (SPR), we demonstrate that mutation of these residues does not abolish TcoALD recognition by Nb474, but does lead to a lack of detection in the Nb474-based homologous sandwich immunoassay.
The results show that the high specificity of the Nb474-based immunoassay is not determined by the initial recognition event between Nb474 and TcoALD, but rather by its homologous sandwich design. This (i) provides insights into the optimal set-up of the assay, (ii) may be of great significance for field applications as it could explain the potential detection escape of certain T. congolense strains, and (iii) may be of general interest to those developing similar assays.
Output:
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Sub-Saharan Africa is plagued by many diseases, which impede its socio-economical development. One of these diseases, Animal African Trypanosomosis, affects livestock and is caused by the parasites of the Trypanosoma genus (T. vivax and T. congolense). Animal African Trypanosomosis leads to considerable economic losses and renders sustainable livestock industry in Sub-Saharan Africa very difficult. In order to proceed with the selective treatment of infected animals, they need to be properly diagnosed. We recently described the use of an assay to specifically detect T. congolense infections in both experimentally and naturally infected animals. The diagnostic assay employs a Nanobody (Nb), which is the smallest antigen-binding unit derived from camelid heavy-chain only antibodies. Our previous results showed that the Nb-based diagnostic test specifically recognizes T. congolense fructose-1,6-bisphosphate aldolase, a glycolytic enzyme that is well conserved amongst other Trypanosoma species. In this paper, we studied the molecular mechanisms underlying the high specificity of the Nb-based diagnostic assay. The principles derived from this work may be important for the design and improvement of similar diagnostic tests.
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PLOS56
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: In this work we studied the folding process of the hybrid-1 type human telomeric DNA G-quadruplex with solvent and ions explicitly modeled. Enabled by the powerful bias-exchange metadynamics and large-scale conventional molecular dynamic simulations, the free energy landscape of this G-DNA was obtained for the first time and four folding intermediates were identified, including a triplex and a basically formed quadruplex. The simulations also provided atomistic pictures for the structures and cation binding patterns of the intermediates. The results showed that the structure formation and cation binding are cooperative and mutually supporting each other. The syn/anti reorientation dynamics of the intermediates was also investigated. It was found that the nucleotides usually take correct syn/anti configurations when they form native and stable hydrogen bonds with the others, while fluctuating between two configurations when they do not. Misfolded intermediates with wrong syn/anti configurations were observed in the early intermediates but not in the later ones. Based on the simulations, we also discussed the roles of the non-native interactions. Besides, the formation process of the parallel conformation in the first two G-repeats and the associated reversal loop were studied. Based on the above results, we proposed a folding pathway for the hybrid-1 type G-quadruplex with atomistic details, which is new and more complete compared with previous ones. The knowledge gained for this type of G-DNA may provide a general insight for the folding of the other G-quadruplexes.
Output:
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G-quadruplexes are high-order DNA/RNA structures. They are involved in the regulation of telomere maintenance, DNA replication, transcription and translation, and are also attractive drug designing targets for treating cancers and promising building blocks for molecular nanodevices. The knowledge of their formation process will improve our understanding of how they achieve their functional structures and then facilitate designing of artificial G-quadruplexes with novel functions. The study of their formation process is also of academic importance, since they involve many different physical chemical factors or interactions, including the hydrogen bonds, the electrostatic effect associated with metal ions, and the syn/anti reorientation of the glycosidic bonds. These make the G-quadruplex a fascinating model system for studying the structure formation of bio-molecules. Furthermore, the study of their formations may enrich the free energy landscape theory that has been well developed for protein folding, but yet to be verified in the other biomolecular systems. Here we computationally study the folding process of the hybrid-1 type human telomeric DNA G-quadruplex and infer a new folding picture, which may also cast a light to the formation of the other G-quadruplexes.
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PLOS57
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: The complexity in composition and function of the eukaryotic nucleus is achieved through its organization in specialized nuclear compartments. The Drosophila chromatin remodeling ATPase ISWI plays evolutionarily conserved roles in chromatin organization. Interestingly, ISWI genetically interacts with the hsrω gene, encoding multiple non-coding RNAs (ncRNA) essential, among other functions, for the assembly and organization of the omega speckles. The nucleoplasmic omega speckles play important functions in RNA metabolism, in normal and stressed cells, by regulating availability of hnRNPs and some other RNA processing proteins. Chromatin remodelers, as well as nuclear speckles and their associated ncRNAs, are emerging as important components of gene regulatory networks, although their functional connections have remained poorly defined. Here we provide multiple lines of evidence showing that the hsrω ncRNA interacts in vivo and in vitro with ISWI, regulating its ATPase activity. Remarkably, we found that the organization of nucleoplasmic omega speckles depends on ISWI function. Our findings highlight a novel role for chromatin remodelers in organization of nucleoplasmic compartments, providing the first example of interaction between an ATP-dependent chromatin remodeler and a large ncRNA.
Output:
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Chromatin structure and function are regulated by the concerted activity of covalent modifiers of chromatin, nucleosome remodeling factors, and several emerging classes of non-coding RNAs. ISWI is an evolutionarily conserved ATP-dependent chromatin remodeler playing essential roles in chromosome condensation, gene expression, and DNA replication. ISWI activity has been involved in a variety of nuclear functions including telomere silencing, stem cell renewal, neural morphogenesis, and epigenetic reprogramming. Using an in vivo assay to identify factors regulating ISWI activity in the model system Drosophila melanogaster, we recovered a genetic interaction between ISWI and hsrω. The hsrω gene encodes multiple non-coding RNAs (ncRNAs), of which the >10 kb nuclear hsrω-n RNA, with functional homolog in mammals, is essential for the assembly and organization of hnRNP-containing nucleoplasmic omega speckles. These special nuclear compartments play essential roles in the storage/sequestration of hnRNP family and other proteins, thus playing important roles in mRNA maturation and other regulatory processes. Here we show that the hsrω-n ncRNA interacts in vivo and in vitro with ISWI to directly regulate its ATPase activity. We also provide in vivo data showing that omega speckle nuclear organization depends on ISWI function, highlighting a novel role for chromatin remodelers in nuclear speckles organization.
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PLOS58
|
***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Jaagsiekte sheep retrovirus (JSRV) is a unique oncogenic virus with distinctive biological properties. JSRV is the only virus causing a naturally occurring lung cancer (ovine pulmonary adenocarcinoma, OPA) and possessing a major structural protein that functions as a dominant oncoprotein. Lung cancer is the major cause of death among cancer patients. OPA can be an extremely useful animal model in order to identify the cells originating lung adenocarcinoma and to study the early events of pulmonary carcinogenesis. In this study, we demonstrated that lung adenocarcinoma in sheep originates from infection and transformation of proliferating type 2 pneumocytes (termed here lung alveolar proliferating cells, LAPCs). We excluded that OPA originates from a bronchioalveolar stem cell, or from mature post-mitotic type 2 pneumocytes or from either proliferating or non-proliferating Clara cells. We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection and transformation. On the contrary, healthy adult sheep, which are normally resistant to experimental OPA induction, exhibit a relatively low number of LAPCs and are resistant to JSRV infection of the respiratory epithelium. Importantly, induction of lung injury increased dramatically the number of LAPCs in adult sheep and rendered these animals fully susceptible to JSRV infection and transformation. Furthermore, we show that JSRV preferentially infects actively dividing cell in vitro. Overall, our study provides unique insights into pulmonary biology and carcinogenesis and suggests that JSRV and its host have reached an evolutionary equilibrium in which productive infection (and transformation) can occur only in cells that are scarce for most of the lifespan of the sheep. Our data also indicate that, at least in this model, inflammation can predispose to retroviral infection and cancer.
Output:
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The identification of cells that give origin to cancer is critical in order to design effective therapeutic strategies. To this end, the early stages of cancer are the most informative but they are seldom associated with clinical symptoms and therefore pass unnoticed in human patients. Studies on animal tumors are invaluable to this research area. In this study, we determined the cells originating an infectious lung cancer of sheep (ovine pulmonary adenocarcinoma, OPA) that is similar to some forms of human pulmonary adenocarcinoma. OPA is caused by a virus known as Jaagsiekte sheep retrovirus (JSRV). We show that OPA is caused by JSRV infection of proliferating type 2 pneumocytes (lung alveolar proliferating cells, LAPCs). We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection while healthy adult sheep exhibit a relatively low number of LAPCs and are resistant to OPA induction. However, adult sheep were susceptible to JSRV infection when the presence of LAPCs was stimulated by induction of a mild injury to the respiratory epithelium. Thus, our study identifies the cells originating lung adenocarcinoma in OPA and shows that inflammation to the respiratory epithelium can predispose to retrovirus infection and cancer.
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PLOS59
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***TASK***
the task is to simplify the input abstract of a biomedical literature
***INPUT***
the input is the abstract of a biomedical literature
***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature
***DOCUMENTATION***
***EXAMPLES***
Input: Congenital human cytomegalovirus (HCMV) infection is the leading cause of neurological disabilities in children worldwide, but the mechanisms underlying these disorders are far from well-defined. HCMV infection has been shown to dysregulate the Notch signaling pathway in human neural progenitor cells (NPCs). As an important downstream effector of Notch signaling, the transcriptional regulator Hairy and Enhancer of Split 1 (Hes1) is essential for governing NPC fate and fetal brain development. In the present study, we report that HCMV infection downregulates Hes1 protein levels in infected NPCs. The HCMV 72-kDa immediate-early 1 protein (IE1) is involved in Hes1 degradation by assembling a ubiquitination complex and promoting Hes1 ubiquitination as a potential E3 ubiquitin ligase, followed by proteasomal degradation of Hes1. Sp100A, an important component of PML nuclear bodies, is identified to be another target of IE1-mediated ubiquitination. A C-terminal acidic region in IE1, spanning amino acids 451 to 475, is required for IE1/Hes1 physical interaction and IE1-mediated Hes1 ubiquitination, but is dispensable for IE1/Sp100A interaction and ubiquitination. Our study suggests a novel mechanism linking downregulation of Hes1 protein to neurodevelopmental disorders caused by HCMV infection. Our findings also complement the current knowledge of herpesviruses by identifying IE1 as the first potential HCMV-encoded E3 ubiquitin ligase.
Output:
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Congenital human cytomegalovirus (HCMV) infection is the leading cause of neurological disabilities in children, but the underlying pathogenesis of this infection remains unclear. Hes1, an important effector of Notch signaling, governs the fate of neural progenitor cells (NPCs) and fetal brain development. Here we demonstrate that: (1) HCMV infection results in loss of Hes1 protein in NPCs; (2) the HCMV immediate-early 1 protein (IE1) mediates Hes1 protein downregulation through direct interaction, which requires amino acids 451–475; (3) IE1 assembles a Hes1 ubiquitination complex and mediates Hes1 ubiquitination; and (4) IE1 also assembles an Sp100A ubiquitination complex and mediates Sp100A ubiquitination, but does not require amino acids 451–475. These results suggest that HCMV IE1 is a potential E3 ubiquitin ligase. Downregulation of Hes1 by HCMV infection and IE1 implies a novel mechanism linking Hes1 depletion to virus-induced neuropathogenesis.
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