The Caenorhabditis elegans genome consists of homologs of about two-thirds of human being disease genes, rendering it a highly enriched and specialized model organism for study on maturing, age-related diseases, longevity and drug screening. However, compared to additional mammals it lacks some essential anatomical features like a blood transport system, a first-pass metabolism process in the liver and kidney, and a DNA methylation pathway that may contribute to specific signaling or epigenetic effects.
Adaptive Development: Hermaphrodite C. elegans can self-fertilize
As opposed to most pets in the genus Caenorhabditis, C. elegans have the ability to produce their own sperm (hermaphrodite) and ova in the male soma. This mode of reproduction offers evolved 3 x in the Caenorhabditis genus (Guo et al., 2009; Kiontke et al., 2011; Thomas et al., 2012), and has been an essential step in the evolution of nematode existence period and metapopulations (Felix and Duveau, 2012).
Life-cycle phases
Nematodes are usually born as larvae and subsequently mature into grownup worms as time passes. The life routine is usually regulated by environmental conditions, which permit the worms to change in one developmental phase to another based on food accessibility, stress along with other factors.
Differential nutrient specifications of larvae and adults, the presence of predators and predator-prey interactions are all features of this dynamic way of life (Felix and Duveau, 2012). For example, recently hatched worms undergo four distinct phases: L1; L2d, before they enter the dauer stage and the feeding stage of the grownup life routine; L3; and finally an enlarged adult worm (L4).
A diversified microbiome is present in all of C. elegans natural habitats, including rotting fruits and stems and compost substrates (Figure 2A). Principle coordinate analyses on unweighted UniFrac distances show unique clustering of the C. elegans and corresponding substrate microbiomes no matter study strategy, labs involved and the perturbations caused by servicing of worms under laboratory problems rather than in their natural environments (Shape 2A).
Primary bacterial taxa are recognized in C. elegans and substrate microbiomes
Detailed analysis of 62 C. elegans and 119 substrate samples revealed a distinctive signature in the community composition of each studied microbiome. The resulting core microbiome is rich in diverse, but overlapping OTUs that display strong commonality across all 62 worm and substrate microbiomes (Physique 3).
Some of the identified bacterial taxa also occur within the same phyla in other, related nematode groups, such as the Caenorhabditis tropicalis team (Guo et al., 2015). Others can be found in both nematode groupings as well, like the Acidobacteriaceae and Planctomycetes, that are not abundant in organic worm microbiomes but can be found at high levels in some of them (Figure 3B).
Acetobacteriaceae along with other Proteobacteria appear to be the keystone taxa of the association with presently unknown functionality.
These bacteria will probably support the fitness of a lot of worm populations by providing them with an essential group of nutrients, allowing the nematodes to survive in stressful or limited environments. Moreover, they might play an important role in the development of a specialized host-microbiome interaction that is essential for adaptation and survival of nematodes. These associations are usually amazingly consistent across several sample varieties, suggesting these bacterial taxa provide a key services to C. elegans that is specific to this nematode and is independent of other, more prevalent bacteria within their environment.