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[
WormBook,
2006]
Although several Caenorhabditis species are now studied in laboratories in great detail, the knowledge of the ecology of most Caenorhabditis species is scarce. In this chapter we present data on the habitat, animal associations, and geographical distribution of the eighteen described and five undescribed Caenorhabditis species currently known to science. The habitats of these species are very diverse, ranging from rotting cactus tissue to inflamed auditory canals of zebu cattle. Some species, including C. elegans , have only been isolated from anthropogenic habitats. Consequently, their natural habitat is unknown. All Caenorhabditis species are colonizers of nutrient- and bacteria-rich substrates and none of them is a true soil nematode. Dauer juveniles of many Caenorhabditis species were shown to be associated with terrestrial arthropods or gastropods. An association with invertebrates is also likely for the remaining species. The type of association is either phoresy (for transport to a new habitat) or necromeny (to secure the body of the associated animal as a future food source). There are also some records of Caenorhabditis species associated with vertebrates. The Caenorhabditis stem species was probably a colonizer of nutrient-rich substrates and was phoretic on arthropods. Some evolutionary trends within the taxon are discussed.
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[
2009]
This chapter focuses on the nematode (roundworm) Caenorhabditis elegans as an example of the phylum Nematoda. C. elegans provides a powerful genetic system for studying glycans during embryological development and in primitive organ systems.
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[
WormBook,
2005]
C. elegans is a member of a group of nematodes called rhabditids, which encompasses a large number of ecologically and genetically diverse species. A new, preliminary phylogenetic analysis is presented for concatenated sequences of three nuclear genes for 48 rhabditid and diplogastrid species (including 10 Caenorhabditis species), as well as four species representing the outgroup. Although many relationships are well-resolved, more data are still needed to resolve some key relationships, particularly near the base of the rhabditid tree. There is high confidence for two major clades: (1) a clade comprising Mesorhabditis Parasitorhabditis, Pelodera, Teratorhabditis plus a few other species; (2) a large clade (Eurhabditis) comprising most of the remaining rhabditid genera, including Caenorhabditis and its sistergroup Protorhabditis-Prodontorhabditis-Diploscapter. Eurhabditis also contains the parasitic strongylids, the entomopathogenic Heterorhabditis, and the monophyletic group Oscheius which includes the satellite model organism O. tipulae. The relationships within Caenorhabditis are well resolved. The analysis also suggests that rhabditids include diplogastrids, to which the second satellite model organism Pristionchus pacificus belongs. Genetic disparity within Caenorhabditis is as great as that across vertebrates, suggesting Caenorhabditis lineages are quickly evolving, ancient, or both. The phylogenetic tree can be used to reconstruct evolutionary events within rhabditids. For instance, the reproductive mode changed multiple times from gonochorism to hermaphroditism, but only once from hermaphroditism to gonochorism. Complete retraction of the male tail tip, leading to a blunt, peloderan tail, evolved at least once. Reversions to unretracted tail tips occurred within both major rhabditid groups. The phylogeny also provides a guide to species which would be good candidates for future genome projects and comparative studies.
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Each year hundreds of students and practicing scientists join in the study of the soil nematode Caenorhabditis elegans. Their reasons for doing so are varied, but at the core these individuals are uniformly impressed by the cohesiveness and generosity of the C. elegans research community, the focused effort to understand every aspect of C. elegans biology, the power and flexibility of the...
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Programmed cell death is a common cell fate in most if not all multicellular organisms. Apoptosis, which will be used as a synonym for programmed cell death throughout this chapter, occurs extensively during development as well as during later life. The development of the nematode worm Caenorhabditis elegans provides a good example of the extensive use of programmed cell death.
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[
1992]
Caenorhabditis elegans is a small soil nematode which is currently being extensively studied to discern general principles of how genes control development. The short life cycle, ability to culture in quantities sufficient for biochemical work, well-developed genetics, small cell number for a rather sophisticated animal, and rapidly increasing possibilities for molecular genetics are features that make this species a very productive system
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[
Methods Mol Biol,
2011]
PhospoPep version 2.0 is a project to support systems biology signaling research by providing interactive interrogation of MS-derived phosphorylation data from four different organisms. Currently the database hosts phosphorylation data from the fly (Drosophila melanogaster), human (Homo sapiens), worm (Caenorhabditis elegans), and yeast (Saccharomyces cerevisiae). The following will give an overview of the content and usage of the PhosphoPep database.
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[
WormBook,
2005]
Nervous systems are characterized by an astounding degree of cellular diversity. The nematode Caenorhabditis elegans has served as a valuable model system to define the genetic programs that serve to generate cellular diversity in the nervous system. This review discusses neuronal diversity in C. elegans and provides an overview of the molecular mechanisms that define and specify neuronal cell types in C. elegans.
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[
Methods Cell Biol,
1995]
This chapter has two aims. First, we describe one method, the electropharyngeogram (EPG), insufficient detail that a Caenorhabditis elegans researcher unfamiliar with electrophysiological methods could set up the apparatus and get useful results. Second, we describe more generally for researchers familiar with electrophysiological methods how they may be applied to C. elegans. We do not describe methods for electrophysiological investigation of C. elegans sperm.
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[
WormBook,
2005]
Nematodes are the most abundant type of animal on earth, and live in hot springs, polar ice, soil, fresh and salt water, and as parasites of plants, vertebrates, insects, and other nematodes. This extraordinary ability to adapt, which hints at an underlying genetic plasticity, has long fascinated biologists. The fully sequenced genomes of Caenorhabditis elegans and Caenorhabditis briggsae, and ongoing sequencing projects for eight other nematodes, provide an exciting opportunity to investigate the genomic changes that have enabled nematodes to invade many different habitats. Analyses of the C. elegans and C. briggsae genomes suggest that these include major changes in gene content; as well as in chromosome number, structure and size. Here I discuss how the data set of ten genomes will be ideal for tackling questions about nematode evolution, as well as questions relevant to all eukaryotes.