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[
BMC Ecol,
2015]
BACKGROUND: How do very small animals with limited long-distance dispersal abilities move between locations, especially if they prefer ephemeral micro-habitats that are only available for short periods of time? The free-living model nematode Caenorhabditis elegans and several congeneric taxa appear to be common in such short-lived environments, for example decomposing fruits or other rotting plant material. Dispersal is usually assumed to depend on animal vectors, yet all current data is based on only a limited number of studies. In our project we performed three comprehensive field surveys on possible invertebrate vectors in North German locations containing populations of C. elegans and two related species, especially C. remanei, and combined these screens with an experimental analysis of persistence in one of the vector taxa. RESULTS: Our field survey revealed that Caenorhabditis nematodes are commonly found in slugs, isopods, and chilopods, but are not present in the remaining taxonomic groups examined. Surprisingly, the nematodes were frequently isolated from the intestines of slugs, even if slugs were not collected in close association with suitable substrates for Caenorhabditis proliferation. This suggests that the nematodes are able to enter the slug intestines and persist for certain periods of time. Our experimental analysis confirmed the ability of C. elegans to invade slug intestines and subsequently be excreted alive with the slug feces, although only for short time periods under laboratory conditions. CONCLUSIONS: We conclude that three invertebrate taxonomic groups represent potential vectors of Caenorhabditis nematodes. The nematodes appear to have evolved specific adaptations to enter and persist in the harsh environment of slug intestines, possibly indicating first steps towards a parasitic life-style.
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[
J Vis Exp,
2022]
The nematode Caenorhabditis elegans interacts with a large diversity of microorganisms in nature. In general, C. elegans is commonly found in rotten plant matter, especially rotten fruits like apples or on compost heaps. It is also associated with certain invertebrate hosts such as slugs and woodlice. These habitats are rich in microbes, which serve as food for C. elegans and which can also persistently colonize the nematode gut. To date, the exact diversity and consistency of the native C. elegans microbiota across habitats and geographic locations is not fully understood. Here, we describe a suitable approach for isolating C. elegans from nature and characterizing the microbiota of worms. Nematodes can be easily isolated from compost material, rotting apples, slugs, or attracted by placing apples on compost heaps. The prime time for finding C. elegans in the Northern Hemisphere is from September until November. Worms can be washed out of collected substrate material by immersing the substrate in buffer solution, followed by the collection of nematodes and their transfer onto nematode growth medium or PCR buffer for subsequent analysis. We further illustrate how the samples can be used to isolate and purify the worm-associated microorganisms and to process worms for 16S ribosomal RNA analysis of microbiota community composition. Overall, the described methods may stimulate new research on the characterization of the C. elegans microbiota across habitats and geographic locations, thereby helping to obtain a comprehensive understanding of the diversity and stability of the nematode's microbiota as a basis for future functional research.
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[
Trends Genet,
2015]
Functional information about the large majority of the genes is still lacking in the classical eukaryotic model species Drosophila melanogaster, Caenorhabditis elegans, and Mus musculus. Because many of these genes are likely to be important in natural settings, considering explicit ecological information should increase our knowledge of gene function. Using C. elegans as an example, we discuss the importance of biotic factors as a driving force in shaping the composition and structure of the nematode genome. We highlight examples for which consideration of ecological information and natural variation have been key to the identification of novel, unexpected gene functions, and use these examples to define future research avenues for the classical genetic model taxa.
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[
Ecol Evol,
2015]
The nematode Caenorhabditis elegans is a central laboratory model system in almost all biological disciplines, yet its natural life history and population biology are largely unexplored. Such information is essential for in-depth understanding of the nematode's biology because its natural ecology provides the context, in which its traits and the underlying molecular mechanisms evolved. We characterized natural phenotypic and genetic variation among North German C. elegans isolates. We used the unique opportunity to compare samples collected 10 years apart from the same compost heap and additionally included recent samples for this and a second site, collected across a 1.5-year period. Our analysis revealed significant population genetic differentiation between locations, across the 10-year time period, but for only one location a trend across the shorter time frame. Significant variation was similarly found for phenotypic traits of likely importance in nature, such as choice behavior and population growth in the presence of pathogens or naturally associated bacteria. Phenotypic variation was significantly influenced by C. elegans genotype, time of isolation, and sampling site. The here studied C. elegans isolates may provide a valuable, genetically variable resource for future dissection of naturally relevant gene functions.
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[
BMC Ecol,
2014]
BACKGROUND: Although the nematode Caenorhabditis elegans is a major model organism in diverse biological areas and well studied under laboratory conditions, little is known about its ecology. Therefore, characterization of the species' natural habitats should provide a new perspective on its otherwise well-studied biology. The currently best characterized populations are in France, demonstrating that C. elegans prefers nutrient- and microorganism-rich substrates such as rotting fruits and decomposing plant matter. In order to extend these findings, we sampled C. elegans continuously across 1.5years from rotting apples and compost heaps in three North German locations. RESULTS: C. elegans was found throughout summer and autumn in both years. It shares its habitat with the related nematode species C. remanei, which could thus represent an important competitor for a similar ecological niche. The two species were isolated from the same site, but rarely the same substrate sample. In fact, C. elegans was mainly found on compost and C. remanei on rotten apples, possibly suggesting niche separation. The occurrence of C. elegans itself was related to environmental humidity and rain, although the correlation was significant for only one sampling site each. Additional associations between nematode prevalence and abiotic parameters could not be established. CONCLUSIONS: Taken together, our findings vary from the previous results for French C. elegans populations in that the considered German populations always coexisted with the congeneric species C. remanei (rather than C. briggsae as in France) and that C. elegans prevalence can associate with humidity and rain (rather than temperature, as suggested for French populations). Consideration of additional locations and time points is thus essential for full appreciation of the nematode's natural ecology.
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[
MicroPubl Biol,
2021]
MEC-4 and UNC-8 are subunits of the DEG/ENaC family of voltage-independent Na+ channels in C. elegans (Driscoll and Chalfie 1991, Canessa, Horisberger et al. 1993, Waldmann, Champigny et al. 1996, Waldmann, Champigny et al. 1997, de Weille, Bassilana et al. 1998, Waldmann and Lazdunski 1998). While MEC-4 is expressed in body touch neurons where it mediates the transduction of gentle touch sensation (Driscoll and Chalfie 1991, O'Hagan, Chalfie et al. 2005), UNC-8 is primarily expressed in motoneurons where it is involved in synaptic remodeling during development (Tavernarakis, Shreffler et al. 1997, Miller-Fleming, Petersen et al. 2016). Both MEC-4 and UNC-8 can be hyperactivated by genetic mutations that hinder channel closing, called (d) mutations (Driscoll and Chalfie 1991, Shreffler, Magardino et al. 1995, Goodman, Ernstrom et al. 2002, Wang, Matthewman et al. 2013). C. elegans neurons and Xenopus oocytes expressing these hyperactive variants of MEC-4 and UNC-8 undergo cell death due to uncontrolled flux of ions into the cell. Cell death in Xenopus oocytes and in cultured C. elegans neurons can be prevented by incubation with the DEG/ENaC channel blocker amiloride (Goodman, Ernstrom et al. 2002, Suzuki, Kerr et al. 2003, Wang, Matthewman et al. 2013).
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[
BMC Genomics,
2007]
ABSTRACT: BACKGROUND: In the genome of Caenorhabditis elegans, homopolymeric poly-G/poly-C tracts (G/C tracts) exist at high frequency and are maintained by the activity of the DOG-1 protein. The frequency and distribution of G/C tracts in the genomes of C. elegans and the related nematode, C. briggsae were analyzed to investigate possible biological roles for G/C tracts. RESULTS: In C. elegans, G/C tracts are distributed along every chromosome in a non-random pattern. Most G/C tracts are within introns or are close to genes. Analysis of SAGE data showed that G/C tracts correlate with the levels of regional gene expression in C. elegans. G/C tracts are over-represented and dispersed across all chromosomes in another Caenorhabditis species, C. briggase. However, the positions and distribution of G/C tracts in C. briggsae differ from those in C. elegans. Furthermore, the C. briggsae
dog-1 ortholog CBG19723 can rescue the mutator phenotype of C. elegans
dog-1 mutants. CONCLUSIONS: The abundance and genomic distribution of G/C tracts in C. elegans, the effect of G/C tracts on regional transcription levels, and the lack of positional conservation of G/C tracts in C. briggsae suggest a role for G/C tracts in chromatin structure but not in the transcriptional regulation of specific genes.
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Horng JC, Nazilah KR, Wang TL, Hsu HL, Wang CC, Wang SW, Chuang TH, Antika TR, Tseng YK, Pan HC, Chrestella DJ, Wang SC
[
J Biol Chem,
2023]
Alanyl-tRNA synthetase (AlaRS) retains a conserved prototype structure throughout its biology. Nevertheless, its C-terminal domain (C-Ala) is highly diverged and has been shown to play a role in either tRNA or DNA binding. Interestingly, we discovered that Caenorhabditis elegans cytoplasmic C-Ala (Ce-C-Ala<sub>c</sub>) robustly binds both ligands. How Ce-C-Ala<sub>c</sub> targets its cognate tRNA and whether a similar feature is conserved in its mitochondrial counterpart remain elusive. We show that the N- and C-terminal subdomains of Ce-C-Ala<sub>c</sub> are responsible for DNA and tRNA binding, respectively. Ce-C-Ala<sub>c</sub> specifically recognized the conserved invariant base G<sup>18</sup> in the D-loop of tRNA<sup>Ala</sup> through a highly conserved lysine residue, K934. Despite bearing little resemblance to other C-Ala domains, C. elegans mitochondrial C-Ala (Ce-C-Ala<sub>m</sub>) robustly bound both tRNA<sup>Ala</sup> and DNA and maintained targeting specificity for the D-loop of its cognate tRNA. This study uncovers the underlying mechanism of how C. elegans C-Ala specifically targets the D-loop of tRNA<sup>Ala</sup>.
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[
Journal of Thermal Biology,
1995]
1. The patterns of HSP70 expression induced in Caenorhabditis elegans by mild (31 degrees C) or severe (34 degrees C) heat shock, and by cadmium ions at 31 degrees C, have been compared with those expressed constitutively ill 20 degrees C controls by 1- and a-dimensional immunoblotting. 2. The 2D spot patterns become more complex with increasing severity of stress (34 degrees C > 31 degrees C + Cd > 31 degrees C > 20 degrees C). 3. A stress-inducible transgene construct is minimally active at 31 degrees C, but is abundantly expressed in the presence of cadmium or at 34 degrees C. 4. Differing degrees or types of stress may differentially induce available
hsp70 -
[
J Nanosci Nanotechnol,
2018]
Uniform and hydrophilic carbon quantum dots (C-QDs) were synthesized by calcination and NaOH treatment from an organo-templated zeolite precursor. The color of luminescence was determined by the concentration of C-QDs. These variable-color C-QDs were applied for the first time in the imaging of Caenorhabditis elegans (C. elegans) as a model organism. The effects of C-QDs and possible behavioral changes in C. elegans were evaluated under treatment conditions. We could clearly observe distribution of C-QDs in C. elegans from the fluorescence images. Furthermore, we observed significant and detectable fluorescence quenching of the C-QDs by free radicals in C. elegans. Our work affirms that C-QDs can be developed as imaging probes and as potential fluorescent quantitative probes for detecting free radicals.