For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. become focus of studies innate immunity and several pathogens have shown to cause lethal intestinal infections in elegans. However none these invade cells, no pathogen isolated from wild-caught Here we describe intracellular that show a new species microsporidia. Microsporidia comprise large class eukaryotic parasites are medically...

Caenorhabditis elegans is a major laboratory model system yet newcomer to the field of population genetics, and relatively little known its biology in wild. Recent studies natural populations at single time point revealed strong spatial structure suggested that these may be very dynamic. We have therefore studied several C. over genotyped them polymorphic microsatellite loci. While some appear genetically stable course observation, others seem go extinct, with full replacement multilocus...

Abstract Caenorhabditis briggsae provides a natural comparison species for the model nematode C. elegans, given their similar morphology, life history, and hermaphroditic mode of reproduction. Despite boasting published genome sequence establishing as genus genetics development, little is known about genetic variation across geographic range this species. In study, we greatly expand collection isolates characterize patterns nucleotide six loci in 63 strains from three continents. The pattern...

The majority of nematodes are gonochoristic (dioecious) with distinct male and female sexes, but the best-studied species, Caenorhabditis elegans , is a self-fertile hermaphrodite. sequencing genomes C. second hermaphrodite, briggsae was facilitated in part by low amount natural heterozygosity, which typifies selfing species. Ongoing genome projects for species seek to approximate this condition intense inbreeding prior sequencing. Here we show that despite inbreeding, heterozygous fraction...

Phenotypes that appear to be conserved could maintained not only by strong purifying selection on the underlying genetic systems, but also stabilizing acting via compensatory mutations with balanced effects. Such coevolution has been invoked explain experimental results, rarely focus of study. Conserved expression driven unc-47 promoters Caenorhabditis elegans and C. briggsae persists despite divergence within a cis-regulatory element between this trans-regulatory environment. Compensatory...

Abstract The nematode Oscheius tipulae belongs to the same family (Rhabditidae) as model species Caenorhabditis elegans . Both reproduce through self‐fertilizing hermaphrodites and facultative males. Recent studies have shown that self‐fertile C. briggsae displayed a 20‐fold lower genetic diversity than male–female remanei Several explanations been put forward account for this difference, including their mode of reproduction dynamic population structure. Here, we present results extensive...

Because there is considerable variation in gene expression even between closely related species, it clear that regulatory mechanisms evolve relatively rapidly. primary sequence conservation an unreliable proxy for functional of cis-regulatory elements, their assessment must be carried out vivo. We conducted a survey C. elegans and species briggsae, remanei, brenneri, japonica. tested enhancers eight genes from these by introducing them into analyzing the patterns they drove. Our results...

Different functional constraints contribute to different evolutionary rates across genomes. To understand why some sequences evolve faster than others in a single cis-regulatory locus, we investigated function and dynamics of the promoter Caenorhabditis elegans unc-47 gene. We found that this consists two distinct domains. The proximal is conserved largely sufficient direct appropriate spatial expression. distal displays little if any conservation between several closely related nematodes....

Abstract A flexible method to image unmodified transcripts and transcription in vivo would be a valuable tool understand the regulation dynamics of transcription. Here, we present novel approach follow native transcription, with fluorescence microscopy, live C. elegans. By using fluorescently tagged Argonaute protein NRDE-3, programmed by exposure defined dsRNA bind nascent gene interest, demonstrate transcript labelling multiple genes, at site cytoplasm. This does not require genetic...

Live labelling of active transcription sites is critical to our understanding transcriptional dynamics. In the most widely used method, RNA sequence MS2 repeats are added transcript interest, on which fluorescently tagged Major Coat Protein binds, and labels transcripts. Here we describe another strategy, using Argonaute protein NRDE-3, repurposed as an RNA-programmable binding protein. We label in C. elegans embryos larvae, without editing gene interest. NRDE-3 programmed by feeding...

Resume Les notions d’epuisement, de burn out ou encore syndrome stress post-traumatique familial sont quasi absentes la litterature psychiatrique professionnelle, alors qu’elles existent dans d’autres disciplines comme gerontologie les soins palliatifs. Pourtant depuis annees 1950, d’abord avec therapies familiales, puis psychoeducation, un travail specifique familles comportant membre porteur trouble schizophrenique a ete developpe. signes reperes par ces courants le fonctionnement (double...