In this issue of Worm

Animals exhibit, and often adapt, specific behaviors depending on their surrounding environment. In fact, the survival of an animal is dependent on the ability to exhibit the correct behavior in a specific environment. However, how the animal is able to sense its environment and correctly select a certain repertoire of behaviors is not well understood. In this short communication , Vidal-Gadea et al. build on their latest paper, " Caenorhabditis elegans selects distinct crawling and swimming gaits via dopamine and serotonin " (PNAS 2011; PMID: 21969584), and investigate the modulation of motor patterns as an animal transitions from one environment to another. Given a complete map of neuronal wiring and known behaviors, the authors illustrate that C. elegans is an ideal model for the study of mechanisms that drive the coordination of adaptive hierarchical behaviors. C. elegans transition through 4 larval stages before reaching adulthood, molting after each stage. Before molting, the worm enters an interesting stage known as Lethargus. This stage resembles sleep in many ways. The animals show homeosta-sis, an increase in arousal threshold and reversibility. However, reduced muscle contraction and a typical sleep posture, two indicators for a sleep-like state, have not been previously described, until now. In this short communication, Juliane Schwarz, Jan-Philipp Spies and Henrik Bringmann were able to address this question by generating and studying transgenic worms that express the calcium sensor GCaMP3.35 in striated body muscle walls. This calcium sensor allowed for the detection of calcium influx in muscle cells, a sure indicator of muscle activity. The group observed the animals in high resolution over a long period by placing a small number of animals in unique agarose hydrogel microcompart-ments (J Neurosci Methods 2011; PMID: 21801751). Using these techniques, they were able to determine that Lethargus is indeed a sleep-like state as C. elegans do assume a relaxed posture and a reduction in muscle activity during Lethargus. Anyone involved in nematode research is probably no stranger to WormBase. WormBase is an extremely useful bioinfor-matic database full of genomic and genetic information. The database covers around 20 different nematodes with a focus on C. elegans. Not only does it serve as an invaluable resource, it also serves as a central repository for nematode data, ensuring that the information available is up to date. This technical review explains how the large amount of incoming nematode data is annotated and integrated for an optimal and accurate …


Research Paper: Moving Towards a New Species of C.briggsae?, pp. 189-95
Speciation occurs when two similar species are no longer able to interbreed and create fertile offspring. This diversity is created by an accumulation of genetic barriers over time. In this research paper, Baird and Stonesifer describe one particular genetic barrier between temperate strains and the tropical strain of Caenorhabditis briggsae, AF16. The researchers find that crosses between both strains results in a delayed development phenotype stemming from dysgenic interactions between maternal-and zygyotic-effect loci.

Commentaries: Fighting Pathogens Using G-proteins, pp. 196-201
Protection from invading microorganisms mean that an animal has to mount a response on many different levels-from an immune response to altering its behavior. The coordination of these behaviors in mammals is a complex process and therefore difficult to study. Anderson and McMullan tackle this by using C. elegans as their model. The team addresses their recent findings on G-protein signaling pathways in neurons and epithelial cells that are able to coordinate these behaviors, thus protecting the nematode from pathogenic attack.

Octopamine: A Worm's Norepinephrine, pp. 202-6
In mammals, noradrenergic signaling plays a role in the perception of pain. Increasing our understanding of this mechanism is important as it could lead to some needed, novel analgesics. C. elegans do not synthesize norepinephrine but do produce a an analog, octopamine. In this article, Mills et al. discuss their recent research on octopamine and its similarities to noradrenergic signaling in mammals, specifically in the case of nociception.

The Great Pathogenic Escape, pp. 207-11
In order for a pathogen to spread and infect, it must first be able to release itself successfully from inside the host cell. Cell culture studies are often used to study mechanisms allowing for their release, however, Szumowski, Estes and Troemel use C. elegans instead as this see-through worm is easily visualized and has intact intestinal epithelial cells-a shortcoming of in vitro systems. The group discusses their findings on the mechanism that Nematocida parisii uses for a successful exit from host cells and how this has implications for other common pathogenic exit strategies (Fig. 1).

Silencing by Removal, pp. 212-5
Prone to gene amplifications, infections and transposon activation, nematodes are able to suppress unwanted gene activity with RNA interference and transgenemediated cosuppression. How these two processes work is generally well understood, however, there appears to be another way in which these processes take their effect. Adamo and La Volpe review their recent findings that aside from their expected mechanisms of gene silencing, both RNA interference and transgenemediated cosuppression also increase germ-line apoptosis-yet another effective way to eliminate infected cells, protecting the genome across multiple generations.

To Be or Not to Be, pp. 216-20
Autophagy has two seemingly conflicting roles: as a protective mechanism and to cause cell death. Such ambiguousness  These mutants have a faulty vesicular degradative pathway and therefore accumulate cellular defects that are normally taken care of by this endosomal pathway. The authors describe findings that autophagy is induced in these mutants in a desperate attempt to correct the defects, but are unable to ultimately rescue them. The study provides novel insights on interactions between endosomal and autophagic pathways.

The Molting Timer, pp. 221-30
The timing and coordination of specific developmental events in animals has not yet been resolved. However, studying the molting cycle of C. elegans should be able to provide some keen insights. Monsalve and Frand expand on their recent findings on LIN-42, a protein related to a circadian clock protein, and its role as part of a molting timer. This timer may offer a solution to the question of how rhythmic and developmental processes are integrated (Fig. 2).