Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 18, 2004
Publication Date: June 14, 2004
Citation: Chitwood, D.J. 2004. Steroid metabolism and function in nematodes: an update. Program and Abstracts, 27th International Nematology Symposium, European Soc. of Nematologists. p. 55. 2004.
The nutritional requirement for sterol by nematodes results from their inability to biosynthesize sterols de novo and represents a fundamental difference between parasitic nematodes and their plant or mammalian hosts. Consequently, plant-parasitic nematodes most likely obtain sterols from their hosts and then metabolize them to sterols better suited to nematode growth, development and reproduction. Research utilizing Caenorhabditis elegans as a model organism for phytoparasitic nematode sterol metabolism has revealed that this species can remove the methyl or ethyl substituents present at the C-24 position of the sterol side chain; C-24 alkyl groups are typical of plant sterols but are usually absent in animals. This dealkylation process can be inhibited by 25-azacoprostane. Additionally, C. elegans can perform several metabolic transformations upon the sterol nucleus, such as double bond introduction, removal, or isomerization. The ability of C. elegans and other nematodes to introduce a methyl group at C-4 of the sterol nucleus is unique to nematodes. Recent studies have indicated that 4-methyl sterols play a specific role in nematodes, and that nematode development can be inhibited by AY-9944, an inhibitor of an isomerase involved in the 4-methylation pathway. A proteomic analysis of C. elegans has revealed that 25-azacoprostane induces reductions in the levels of several proteins. Evidence for the role of steroids as hormones in nematodes will be discussed.