text_combined: johvdvutqrpvcaaasalertsorg science online editors choice alert 319 5865 current issue previous issue science express science products science journal editors choice highlights recent literature science volume 319 issue 5865 dated february 15 2008 available httpwwwsciencemagorgcontentvol319issue5865twildtl copy editors choice highlights recent literature section appended editors choice highlights recent literature february 15 2008 319 5865 editors choice highlights recent literature ecologyevolution merrier andrew sugden relationship number species ecological community functional aspects ecosystem usually studied experimentally observing effects random changes diversity however study rocky intertidal pools reveals nonrandom variation species diversity characteristic natural habitats yields better predictions functional effects experiments species composition altered randomly bracken et al quantified effects kinds variation seaweed diversity nutrient dynamics nitrogen uptake set tide pools number species increased disturbance caused heavy surf decreased effects natural realistic variation compared effects artificial diversity gradients established random groupings species increased diversity realworld pools associated higher rates nutrient acquisition plants whereas artificial communities showed relationship results present new challenges experimental ecologists studying consequences biodiversity loss ecosystems ams proc natl acad sci usa 105 924 2008 molecular biology wobble superwobble guy riddihough cases one triplet codon specify amino acidat one extreme leucine encoded six nucleotide triplets degenerate codons tend vary third position basis francis cricks wobble hypothesis codon must recognized cognate transfer rna trna anticodon strictly complementary first two positions use nonstandard basepairing third wobble position applying complementarity rules indicates minimum 32 trnas would needed read 64 possible triplet codons yet human mitochondria plant plastids fewer 32 distinct trnas leading suggestion trnas u wobble position might able make deficit pairing four bases third position codonvia socalled superwobble plastids tobacco plants two trna genes code amino acid glycine gly trnaglygcc decode ggc ggu gly codons trnaglyucc according superwobble hypothesis able decode regular gly codons gga ggg also ggc ggu rogalski et al support idea individually knocking trnagly genes showing superwobble trna essential cell survival although trnaglyucc suffices accurate reading code superwobble translation efficiency nonetheless seems reduced explaining superwobble rarely selected genetic systems gr nat struct molec biol 15 101038nsmb1370 2008 biomaterials seeping cartilage marc lavine polymer nanoparticles explored accurate delivery drugs improve efficacy reduce toxicity within body tissues lacking vasculature articular cartilage challenge get drug dense extracellular matrix ecm via localized injection without removal synovial fluid rothenfluh et al synthesized polypropylene sulfide pps particles ranging size 20 200 nm could potentially used deliver hydrophobic drugs aggrecanase inhibitors used treat osteoarthritis pps particles decorated peptide sequence obtained fivegeneration phage panning process cloning enhances population sequences best bind target tissue best sequence obtained binding tests target peptide related scrambled sequence showed binding sequencespecific collagen ii 1 smallest particles able enter ecm targeting peptide caused bind collagen matrix thus turning barrier reservoir persisted 96 hours msl nat mater 7 101038nmat2116 2008 physiology neural vulnerability hypertension peter stern rising blood pressure typical stress responseusually healthy adaptive reaction dangerous situations increases ones chances survival however individuals excessive stressorevoked blood pressure increases risk developing cardiovascular disease later life fmri study undergraduates charged choosing word names color target word stroop colorword interference task gianaros et al connect stressor processing brainstem cardiovascular control mechanisms regulating blood pressure people higher stressorevoked blood pressure reactivity displayed activation amygdala especially dorsal part contains central nucleus individuals showing greater blood pressure reactivity also lower amygdala gray matter volume predicted greater amygdala activation addition greater stressor evoked blood pressure reactivity correlated stronger functional connectivity amygdala area brainstem called pons critical blood pressure control well perigenual anterior cingulate cortex pacc amygdala greater activation pacc associated lower pacc gray matter volume results indicate role amygdala projection areas mediating individual differences autonomic stress responses hence vulnerability psychological stressors prs j neurosci 28 990 2008 chemistry tracking surface shakes jake yeston twodimensional infrared 2dir spectroscopy recently proven useful tracking chemical dynamics shifts detected molecular vibrations 2d refers spatial framework rather initial final sets mode populations simultaneously monitored different vibrational frequencies bredenbeck et al extend technique achieve surface specificity combining sum frequency generation sfg latter wellestablished class spectroscopy affords backgroundfree signal arising additive mixing two different frequencies light interfacea process fails build intensity bulk 3d environment polarizations stacked molecular layers cancel one another authors applied sfg 2dir hybrid characterization vibrational energy flow hydrophobic alkyl tails protruding waterdodecanol interface jsy j chem soc 130 101021ja710099c 2008 biochemistry whats good gilbert chin enzyme kinetics subject dreaded hardcore biochemists purifying proteins measuring product generated substrate consumed varying concentrations enzyme substratenot mention characterization competitive noncompetitive inhibitorsand integrating data within mechanistic scheme spits rate constants well stuff dreams made neither reading someone elses enzyme kinetics papers umejiego et al applied kind information random order substrate binding ratelimiting hydrolysis covalent enzyme intermediate designing smallmolecule screen inhibitors enzyme inosine5monophosphate dehydrogenase impdh care impdh salvages purines order supply guanine human pathogen cryptosporidium parvum c parvum enzyme differs enough human impdh serve drug target screening kinetically defined conditions conserved imp site occupied whereas less conserved nad site empty managed fish 10 candidates starting pool 44000 compounds four potent inhibitors c parvum growth standard drug paromomycin cell culture assay gjc chem biol 15 70 2008 chemistry dnas selfregard phil szuromi recognition doublestranded ds dna sequences usually thought require unwinding double helix expose bases interactions singlestranded nucleic acid sequences proteins thus would reasonable assume recognition dsdna sequences solution would require processes involving singlestranded dna triplehelix formation baldwin et al examined binary mixture two different dsdna sequences identical length 294 base pairs gc base proportion 50 electrolytic solution minor osmotic stress conditions low fluorescent labeling avoid quenching liquid crystalline spherulites form two dnas within structures prefer selfassociate rather mix authors suggest based recent theoretical work association identical dnas favored arrangement maintains registry phosphate backbone surrounding counterions different sequences result small changes pitch disrupt interactions extract energetic penalty mechanisms may also operate dsdna recognition occurs presence intervening solution pds j phys chem b 112 1060 2008 unsubscribe edit subscriptions service httpwwwsciencemagorgcgialertsmain written requests unsubscribe may sent customer service 1454 page mill road palo alto ca 94304 usa magazine news signaling careers 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