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United States Department of Agriculture

Agricultural Research Service

Title: Sterol Metabolism in Nematodes: Failure of Caenorhabditis Elegans to Biosynthesize Ecdysone

Author
item Chitwood, David

Submitted to: International News on Fat, Oils, and Other Related Materials (INFORM)
Publication Type: Abstract Only
Publication Acceptance Date: April 28, 1996
Publication Date: N/A

Technical Abstract: Because of speculation that nematodes may use the same hormones that insects use to regulate molting and other developmental processes, an attempt was made to isolate and identify ecdysteroids from Caenorhabditis elegans. Initially, nematodes were propagated in a sterile, semidefined, aqueous medium; ecdysteroids were chromatographically purified and quantified by radioimmunoassay. Although C. elegans contained the immunoreactive equivalent of 460 pg ecdysone per gram dry weight, the quantity of culture medium used to propagate the nematodes contained the immunoreactive equivalent of 68 times the quantity within the nematodes. Therefore, a defined medium lacking ecdysteroid immunoreactivity was created; C. elegans propagated in this medium contained 520 pg ecdysone equivalents per gram dry weight. Although nematode reproduction in this aqueous medium was much poorer than in aqueous semidefined medium, reproduction improved when the defined medium was formulated with agar. When C. elegans was cultured in either agar-based or aqueous defined medium supplemented with radiolabeled cholesterol, no radiolabeled free ecdysteroids or polar or apolar ecdysteroid conjugates were detected in nematodes or in exhausted culture medium. This failure to demonstrate the conversion of cholesterol to ecdysteroids in C. elegans indicates that the ecdysteroids previously detected in nematodes may be dietary in origin.

Last Modified: 10/24/2014
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