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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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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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[
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,
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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A previous chapter in this series (1) described, primarily, the physical mapping of the 100 Mb Caenorhabditis elegans genome by fingerprinting of cosmid clones, and the linking of the contigs thus derived by YAC hybridization. At that time, the primary function of the map was to enhance the molecular genetics of the organism by facilitating the cloning of known genes, and to serve as an archive for genomic information. However, a clonal physical map - even with good alignment to the genetic map - carries only a tiny proportion of the information present in the genome. Consequently, the current objective of the C. elegans genome project (2) is to establish of the entire genomic sequence. The bacterial clone map, although incomplete by virtue of the uncloneability of regions of the genome in cosmid vectors (a factor which we shall discuss later in this chapter), has proved a sound basis for the systematic sequence analysis. The sevenfold cosmid coverage has a resolution sufficient to enable the selection of a subset of cosmids for sequencing such that, on average, each clone contributes 30 kb of unique sequence to the whole. Sequencing projects based on bacterial clone maps (3-5) of a number of other genomes of a range of sizes are also well advanced, in particular Saccharomyces cerevisiae (15 Mb; complete), Schizosaccharomyces pombe (15Mb), and Drosohpila melanogaster (150 Mb). Although it has recently been demonstrated that small bacterial genomes can be sequenced by direct shotgun sequence analysis of the entire genome with no prior mapping (6), the ability to interrelate and map clone sets, whether derived by random selection of in a directed manner, is still the most convenient route to the sequence analysis of larger genomes.
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[
1985]
At first sight the inclusion of a chapter on Caenorhabditis elegans in a volume on cell biology may seem unusual. However this nematode has been a superb model system for a number of cell biology studies as well as a useful model of aging. This widespread interest in C. elegans is engendered in large part by its genetic system and its optical clarity in Nomarski phase-contrast optics. Nematodes have long been a system in wide use among experimental gerontologists, and with the introduction of C. elegans by Brenner in 1974, this species has become the nematode of choice for most aging studies. We concentrate primarily on C. elegans in this review although a number of other speices, including Caenorhabditis briggsae, Turbatrix aceti, and Panagrellus redivivus, have been used in aging studies also. Other reviews on aging in C. elegans have appeared recently, including a more detailed review in another volume of this series.
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[
Methods Cell Biol,
1995]
The nematode Caenorhabditis elegans is a small, rapidly growing organism that can easily be raised in the laboratory on the bacterium Escherichia coli. Because C. elegans is a self-fertilizing hermaphrodite, it is possible to readily grow large quantities of the organism in swirling liquid cultures and also possible to propagate severely incapacitated mutants. The rapidity of growth and the ability to self-fertilize necessitate special measures to establish a synchronous culture.
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[
Methods Mol Biol,
2013]
The principle of commonly used methods to create mutations in the nematode Caenorhabditis elegans (C. elegans) is straightforward. In general, worms are exposed to a dose of mutagen resulting in DNA damages and mutations. Screening the progeny of the mutagenized animals for a certain phenotype is the regular forward genetic approach in C. elegans. A mutant selected from such a population is stabilized to recover a pure homozygous strain. In this chapter, we categorize the protocol into mutagenesis, phenotype screen, and outcross and provide time-tested procedures for their implementation to create long-lived worm mutants.
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[
1979]
We have isolated temperature sensitive maternal effect mutants in the free-living nematode Caenorhabditis elegans. We use C. elegans for several basic reasons. It is easy to culture in the laboratory and it has a rapid life cycle. The genetics of C. elegans have been elucidated by Brenner and more recently have been refined by the lethal analysis of Herman et. al. Both embryonic and postembryonic development can be observed directly and conveniently on the living worm with Nomarski differential interference optics because egg shell and worm cuticle are transparent. The precise embryonic cell lineages of C. elegans are known from fertilization to the 200 blastomere stage. All of the postembryonic somatic cell lineages are precisely known. It ...