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United States Department of Agriculture

Agricultural Research Service

Title: Steroid Metabolism and Function in Nematodes: An Update

Author
item Chitwood, David

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.

Technical Abstract: 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.

Last Modified: 4/23/2014
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