Salazar, C. J. et al. (2017) International Worm Meeting "Characterizing the function of a novel allele (dz205) in the development of PVD."

Bulow, H. E., Salazar, C. J., Diaz-Blazac, C. A.

[International Worm Meeting, 2017]

Neuronal development depends on numerous extracellular and intracellular cues to ensure proper dendritic structure and function. However, the mechanisms, which control and ensure proper dendritic development, are incompletely understood and are difficult to study in vivo within vertebrates. C. elegans is an excellent model to determine when and where genetic and molecular signals may be required during different stages of development. In order to better understand dendrite development, we utilized the somatosensory neuron, PVD, with its highly stereotyped 'menorah'-like dendrites. These dendrites are formed through consecutive branching formation of primary, secondary, tertiary, and quaternary dendritic branches. During a genetic screen, we have isolated a mutant allele, dz205, which elicits a characteristic "hyper-branched" phenotype in which the number of dendritic branches of the PVD somatosensory neuron increases. In order to quantify this phenotype, we utilized morphometric analysis to characterize the morphology of PVD at the L4 larval stage. We found the number of ectopic secondary and tertiary increased in mutant animals compared to the wildtype. This finding suggests that the normal function of dz205 is to limit the formation of ectopic branches of PVD dendrites. Currently, our research aims to identify the gene mutant in dz205 and to determine in which tissue the corresponding gene may act during the development of PVD dendrites.

Baird SE et al. (1991) International C. elegans Meeting "REPRODUCTIVE ISOLATION AMONG CAENORHABDITIS SPECIES"

Fitch DHA, Emmons SW, Baird SE, Sutherlin ME

[International C. elegans Meeting, 1991]

We have begun a characterization of reproductive isolating mechanisms among four species of Caenorhabdins, C. elegans, C. briggsae, C. remanei, and C. vulgarensis (n. sp.). Caenorhabditis males readily mate with all congeneric females/hermaphrodites, but do not mate with extrageneric females (Rhabditis terricola and Cuncularia oxycerca). Nor was extrageneric mating induced by the presence of congeneric females, suggesting that Caenorhabditis males selectively recognize congeneric females by a short-range stimulus. Of the twelve pairwise combinations of Caenorhabditis males and females (or hermaphrodites) tested, seven are cross-infertile (i.e. are isolated by gametic mechanisms). The most likely reason for crossinfertility in these combinations is that ova fail to bind interspecific sperm. Five of twelve combinations, including all combinations involving C. remanei females and reciprocal combinations of C. briggsae and C. vulgarensis are cross-fertile. These combinations appear to be partially isolated by gametic mechanisms as interspecific brood sizes are uniformly low. They are further isolated by hybrid lethality and or sterility; most interspecific hybrids arrested as embryos, a few hybrids from the combination of C. briggsae males and C. vulgarensis females survived embryogenesis and either arrested as larvae or developed into sterile adults. All adult hybrids and larval hybrids old enough to score were female (18/18). Two conclusions about the genetic basis of briggsaelvulgarensis hybrid lethality are suggested by these results (and by analogy with lethality in Drosophila melanogaster/D. simulans hybrids). First, there is a lethal factor in the cytoplasm of C. briggsae that is absent from the cytoplasm of C. vulgarensis; female (Cyt(vul) A(vul)A( brg) X(vul)x(brg)) hybrids from C. vulgarensis mothers are marginally vlable whereas genetically identical female (cyt(brg) A(vul)A(brg) X( vul)x(brg) ) hybrids from C. briggsae mothers are inviable. Second, there may be a recessive lethal factor encoded by the X chromosome of C. vulgarensis; some female (Cyt(vul) A(vul)A(brg) X(vul)X(brg) hybrids survive whereas all male (Cyt(vul) A(vul)A(brg) X(vul)O) hybrids die. This recessive lethal would necessarily be suppressed by a recessive suppressor-of-lethality present on a C. vulgarensis autosome.

Liebe B et al. (1997) International C. elegans Meeting "HOMOLOGUES OF PARASITIC NEMATODE CUTICLE PROTEINS IN C. ELEGANS"

Hunt PW, Blaxter ML, Liebe B

[International C. elegans Meeting, 1997]

We are using C. elegans as a model in which to study the organismal function of a number of proteins found in the cuticles of parasitic nematodes. Many strongylid nematode parasites have a cuticular globin as well as a myoglobin: these globins have very high oxygen affinities. C. elegans expresses a myoglobin (but no cuticular isoform). We have determined the sequence of 15 nematode globin genes. They reveal remarkable plasticity in structure, one gene having six introns (the C. elegans gene has but one). The filarial parasitic nematode Brugia expresses at its surface a glutathione peroxidase which appears to be involved in protection against oxyradical attack. We have isolated four C. elegans homologues of these genes: one appears to be a pseudogene, two are members of a nematode family of glutathione peroxidase and one is a member of a class of lipid peroxidases previously undescribed from nematodes.

Oomura, S. et al. (2019) International Worm Meeting "Early embryogenesis of C. inopinata, a sibling species of C.elegans."

Matsumura, Y., Haruta, N., Hoshi, Y., Sugimoto, A., Oomura, S.

[International Worm Meeting, 2019]

C. inopinata is a newly discovered sibling species of C. elegans. Despite their phylogenetic closeness, they have many differences in morphology and ecology. For example, while C. elegans is hermaphroditic, C. inopinata is gonochoristic; C. inopinata is nearly twice as long as C. elegans. A comparative analysis of C. elegans and C. inopinata enables us to study how genomic changes cause these phenotypic differences. In this study, we focused on early embryogenesis of C. inopinata. First, by the microparticle bombardment method we made a C. inopinata line that express GFP::histone in whole body, and compared the early embryogenesis with C. elegans by DIC and fluorescent live imaging. We found that the position of pronuclei and polar bodies were different between these two species. In C. elegans, the female and male pronuclei first become visible in anterior and posterior sides, respectively, then they meet at the center of embryo. On the other hand, the initial position of pronuclei were more closely located in C. inopinata. Also, the polar bodies usually appear in the anterior side of embryo in C. elegans, but they appeared at random positions in C. inopinata. Therefore, we infer that C. inopinata may have a different polarity formation mechanism from that in C. elegans. We are also analyzing temperature dependency of embryogenesis in C. inopinata, whose optimal temperature is ~7 degree higher than that in C. elegans.

Marie-Anne Felix et al. (2008) European Worm Meeting "Bacterial and fungal associates of C. elegans and new Caenorhabditis species from the wild"

Marie-Anne FELIX, David Fitch, Karin Kiontke

[European Worm Meeting, 2008]

Most C. elegans biology is studied under one standard laboratory. condition in one reference genetic background (N2). However, its ecological. and evolutionary framework matters to understand the evolutionary origin of. the mechanisms studied in the laboratory.. C. elegans mostly proliferates in rotting fruits (Barriere and Felix,. Genetics 2007). The examination of C. elegans and C. briggsae individuals. taken directly from rotting fruits samples shows that:. 1. fungi in addition to bacteria can be found in the intestine;. 2. constipation is a recurrent problem;. 3. individuals of some populations are infected by various pathogens,. some of which are unidentified and produce abnormal phenotypes,. such as intestinal cell fusion.. A library of bacterial, fungal and slime mold strains was constructed. from individual rotting fruits from which C. elegans and C. briggsae were. also isolated. The microbes are identified by sequencing a fragment of. 16S/18S rDNA. This library includes putative food and pathogens.. Caenorhabditis species were isolated from wild and domesticated. rotting fruits collected worldwide. We will report on the isolation,. culture and preliminary phylogenetic position of several putative new. Caenorhabditis species of the Elegans group (so far including C. elegans,. C. briggsae, C. remanei and C. brenneri). These new species include:. - C. sp. 5 JU727 (China), a close relative of C. briggsae with a. gonochoristic (male/female) mode of reproduction. - C. sp. 7 JU1199, gonochoristic, a putative outgroup to the four. described species (which is much easier to culture than the next outgroup,. C. japonica). - C. sp. 9 JU1325 and C. sp. 10 JU1333, two gonochoristic species. from India - C. sp. 11, a hermaphroditic species from La Reunion (an. island next to Madagascar).. I am happy to distribute strains. See http://www2.ijm.jussieu.fr/worms for. worm strains. I thank V. Robert, M. Hermann, J. Milloz and many others for. collecting samples, I. Nuez for technical help and E. Troemel and J.. Hodgkin for characterization of two associated microbes (see abstract by. Hodgkin et al.).. Lab priority: If you wish a single talk per lab, I would put F. Duveau''s. abstract as a priority.

LF Molin et al. (1999) International C. elegans Meeting "Comparison of gene expression in C. elegans and C. briggsae"

IA Hope, LF Molin

[International C. elegans Meeting, 1999]

Previously a collection of maternal effect embryonic lethal mutations was screened for their effects on the expression pattern of a pes-1::lacZ fusion gene. Ectopic expression was observed in mutants for the gene emb-46 and, because of the nature of the alteration to the expression pattern, this gene was selected for further study. Using the markers available in the region (+7.2 mu on chromosome II), location of emb-46 was restricted to a region covered by 2 YACs and 8 overlapping cosmids but phenotypic rescue experiments to locate the gene have been unsuccessful so far. Furthermore, using the cosmids covering the region as probes, no RFLPs were detected for any of the seven mutant alleles isolated for this gene. A new project has been started to compare sequence and gene expression pattern data between C. elegans and C. briggsae to identify the location and function of gene regulatory regions. A pilot study was started with 12 genes for which a reproducible and specific expression pattern was described in C. elegans . Plasmids carrying C. elegans gene promoter regions fused to the lacZ reporter gene were injected into C. briggsae germline with the C. elegans rol-6 marker and transmitting lines were established. Expression patterns were found to be similar in both species for ten genes. For the other two genes, F54D5.1 and pes-1, expression in C. briggsae only partially matches the expression observed in C. elegans . No C. briggsae homologue has been sequenced so far for these two genes. The pes-1::lacZ reporter gene is strongly expressed in C. briggsae , as in C. elegans , in the D lineage. In C. briggsae , weak staining is observed in a cluster of a few cells anteriorly that could define a restricted subset of AB descendant cells as compared to the pattern observed in C. elegans . No staining is observed in C. briggsae in the cells Z1 and Z4. In order to isolate the C. briggsae homologue of pes-1, a C. elegans pes-1 cDNA probe has been used to screen a C. briggsae DNA library. Several clones have been identified and are currently been analysed by degenerate PCR and Southern blot experiments.

Gunasekaran Singaravelu et al. (2004) East Asia Worm Meeting "Troponin C: a novel binding partner of Calcineurin A in C elegans."

Changhoon Jee, Hiroaki Kagawa, Joohong Ahnn, Bijaya Kumar Dhakal, Gunasekaran Singaravelu

[East Asia Worm Meeting, 2004]

Calcinerin is a widely distributed serine/threonine phosphatase that is well conserved from yeast to human. Troponin C ( pat-10 ) is a calcium binding protein with EF hand motif and has been shown to play essential roles in muscle cells of C elegans . When the catalytic subunit of Calcineurin (Calcineurin A) was utilized as a bait in yeast two-hybrid screening, many interacting proteins were identified; one of the proteins is Troponin C-1 ( pat-10 ). Surprisingly, Calcineurin A does not bind with Troponin C-1 when bacterially expressed proteins were utilized in vitro . However, when worm lysate were utilized, either of the protein found to interact with each other, as monitored by pull-down assay. This study indicates the novel mode of interaction between Calcineurin A and Troponin C in C elegans . Currently we are investigating the biological meaning of this novel interaction.

LK Cioci et al. (1999) International C. elegans Meeting "Transgenic Strains of the Nematode Caenorhabditis elegans as Biomonitors of Environmental Metal Contamination"

L Qiu, JH Freedman, LK Cioci

[International C. elegans Meeting, 1999]

Transition metal contamination poses a serious environmental and human health threat. The bioavailability of transition metals in environmental samples can only be assessed with living organisms. A transgenic strain of C. elegans has been engineered that can be used to monitor the bioavailability of metals. A reporter transgene consisting of a fragment of the promoter from the C. elegans metallothionein-2 gene ( mtl-2 ) that controls the transcription of a b -galactosidase reporter ( lacZ ) has been integrated into the genome of this organism. By using these transgenic C. elegans , the toxicological response to metals in soil and water samples can quickly be measured with a simple histochemical staining assay. C. elegans that contain the mtl-2/lacZ transgene provide a more sensitive assay of cadmium, mercury, zinc and nickel exposure than LC 50 assays or those using nematodes that contain heat-shock protein-based reporter transgenes. Soil exposure assays also indicated a clear response of the transgenic C. elegans . These studies demonstrate that C. elegans , which contain mtl-2:lacZ transgenes, can function as sensitive toxicological indicators of metal contamination in environmental samples.

Thatcher JD et al. (1997) International C. elegans Meeting "CAFa, A CANDIDATE FACTOR CONTROLLING PHARYNGEAL ORGAN SPECIFIC GENE EXPRESSION"

Thatcher JD, Okkema PG

[International C. elegans Meeting, 1997]

Expression of myo-2, a pharyngeal muscle-specific myosin heavy chain gene, is mediated by a convergence of distinct cell type and organ specific pathways. The organ-specific pathway targets a short DNA sequence within the myo-2 enhancer, called the C sub-element. C is a unique regulatory sequence that enhances reporter gene expression in all pharyngeal cell types, muscle and non-muscle, but is inactive outside the pharynx. To characterize the pathway controlling pharyngeal organ specific gene expression, we performed a yeast one hybrid screen to identify C. elegans factors binding the C sub-element. Multiple clones were isolated for a gene located on the left arm of X, that encode a novel factor provisionally referred to as C associated factor a (CAFa). CAFa specifically interacts with C sub-element sequences in yeast and mutated C sub-elements, which fail to enhance transcription in C. elegans, do not interact with CAFa in yeast. A genomic fragment extending 3.7 kb upstream of the CAFa translation start site induces robust reporter gene expression in both muscle and non muscle cells of the pharynx, as well as the pharyngeal-intestinal valve cell. Occasional expression is also observed in cells outside the pharynx. In embryos, strong CAFa expression is observed in the pharynx as early as the one and a half fold stage. These results suggest that CAFa is a novel factor contributing to gene expression during pharyngeal organogenesis.

Vayndorf, Elena et al. (2017) International Worm Meeting "C. elegans as a model for age-related phenotyping, compound screening and toxicological assessment."

Hincks, Joshua, Vayndorf, Elena, Taylor, Barbara, Harris, Michael

[International Worm Meeting, 2017]

The C. elegans pharynx is a tubular, bi-lobed, muscular pump encased in a basement membrane. The pharynx muscle contracts and relaxes as the animal feeds, generating a characteristic electrical signal that can be recorded as an "electropharyngeogram". The frequency of pharyngeal pumping decreases with age and is considered a reliable index of overall health. Recently, NemaMetrix has made available a device that easily monitors and quantifies the C. elegans electropharyngeogram. We have designed a two-week teaching module using the NemaMetrix platform in guided undergraduate research. Projects assay a locally relevant environmental toxin, a natural product, and the effect of age in C. elegans. We provide examples of research projects that can be done in a two-week research module as part of a biomedically-related undergraduate course.