Pristionchus pacificus: A Genetic Model System for the Study of Evolutionary Developmental Biology and the Evolution of Complex Life-History Traits

Modular metabolite assembly in Caenorhabditis elegans depends on carboxylesterases and formation of lysosome-related organelles

Signaling molecules derived from attachment of diverse metabolic building blocks to ascarosides play a central role in the life history of C. elegans and other nematodes; however, many aspects of their biogenesis remain unclear. Using comparative metabolomics, we show that a pathway mediating formation of intestinal lysosome-related organelles (LROs) is required for biosynthesis of most modular ascarosides as well as previously undescribed modular glucosides. Similar to modular ascarosides, the modular glucosides are derived from highly selective assembly of moieties from nucleoside, amino acid, neurotransmitter, and lipid metabolism, suggesting that modular glucosides, like the ascarosides, may serve signaling functions. We further show that carboxylesterases that localize to intestinal organelles are required for the assembly of both modular ascarosides and glucosides via ester and amide linkages. Further exploration of LRO function and carboxylesterase homologs in C. elegans and other animals may reveal additional new compound families and signaling paradigms.

Isolation of pristionchus nematodes from beetles

INTRODUCTIONIn this procedure, nematodes disembark from a beetle carcass and feed on Escherichia coli OP50. The nematodes are then monitored for a few days and identified using simple morphological characteristics. This method is rapid, easy, and biased for Pristionchus species.

Assessment of the olfactory response to chemicals or bacteria in pristionchus nematodes

INTRODUCTIONIn the soil environment, nematodes must rely on a number of host-specific chemical cues in order to find potential beetle hosts. They must also discriminate among different food choices (i.e., bacteria), which is important because if the nematodes concentrate on an unsuitable food source, they may die. To detect the bacteria and host-specific chemicals, nematodes use sensory structures called amphids and phasmids that are located on the head and tail, respectively. The olfactory response of nematodes can be studied in the laboratory using the very simple agar-based assay described here. This assay determines the attractiveness of Pristionchus to a range of beetle-associated compounds and has allowed detailed molecular mechanisms of olfaction to be studied in Pristionchus. It can also be used to examine the food choice of these nematodes when they are faced with a number of bacteria.