Submitted to: American Society of Cell Biology Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 2, 2002
Publication Date: N/A
Technical Abstract: We are interested in neuropeptides in nematodes as leads to new control agents for parasitic nematodes. This includes physiological aspects of neuropeptide action and metabolic regulation of these peptides. The free-living nematode Caenorhabditis elegans, with its mapped genome, offers unique opportunities to couple molecular genetic background to biochemical and physiological events. Aminopeptidase activity was detected in C. elegans homogenates by using the aminoacyl substrate L-alanine-4-nitroanilide. The bioactive insect peptide adipokinetic hormone (AKH) decreases the apparent aminopeptidase activity and increases Km, suggesting that the peptide competes with the nitroanilide as a substrate in the nematode system. AKH, which mobilizes lipid stores in insects, has been prepared from nematodes and has physiological activity in insects (Davenport et al. 1994. Parasitology. 108: 479-485). It is a decapeptide with a blocked N-terminus (pGlu), and its metabolism has been mapped in insect systems. A chromatographic analysis of digests of AKH by the C. elegans homogenates reveals an initial endoproteolytic cleavage producing a heptapeptide with an unblocked N-terminus that serves as an aminopeptidase substrate. The patterns of subsequent peptide fragment production are identical to the insect system. Aminopeptidase activity is partially inhibited by amastatin as in insects. This evidence for the presence of similar neuropeptides, proteases and neuropeptide metabolism in insects and nematodes suggests that insect systems can provide physiological insight into nematode studies and will supplement the genetic resources of C. elegans.