Recent Developments in Nematode Steroid Biochemistry
AbstractCurrent knowledge of steroid nutrition, metabolism, and function in free-living, plant-parasitic and animal-parasitic nematodes is reviewed, with emphasis upon recent investigation of Caenorhabditis elegans. A number of 4-desmethylsterols with a trans-A/B ring configuration can satisfy the steroid nutritional requirement in C. elegans, but sterols with a cis-A/B ring configuration or trans-A/B sterols with a 4-methyl group cannot. C. elegans removes methyl or ethyl substituents at C-24 of the plant sterols sitosterol, campesterol, stigmasterol, stigmastanol, and 24-methylene-cholesterol to produce various sterols with structures partially dependent upon that of the dietary sterol. Additional metabolic steps in C. elegans include reduction of [delta] ²²- and [delta] [sup5]-bonds, C-7 dehydrogenation, isomerization of a [delta] [sup7]-bond to a [delta] [sup8][sup(] ¹[sup4][sup)]-bond, and 4[alpha]-methylation. An azasteroid and several long-chain alkyl amines interfere with the dealkylation pathway in C. elegans by inhibiting the [delta] ²[sup4]-sterol reductase; these compounds also inhibit growth and reproduction in various plant-parasitic and animal-parasitic nematodes. A possible hormonal role for various steroids identified in nematodes is discussed. Key words: biochemistry, Caenorhabditis elegans, ecdysteroid, hormone, steroid, sterol.
Copyright and Permissions
All material published by the Society of Nematologists (SON), except for papers prepared by United States and Canadian government employees, is copyrighted and protected under the U.S. copyright law. Under the Copyright Act of 1976, the term of copyright for materials registered by an organization is 75 years from the date first published. Before publishing any manuscript, SON requires that authors transfer full and complete ownership of any copyright to SON by signing a JON Page Charge/Copyright Form (.pdf). SON then registers the copyright. Subsequent use of published materials requires written permission from the SON and may be obtained by contacting the current Editor-in-Chief and state where and how the material will be used.
The author warrants that the article is an original work not published elsewhere in whole or in part, except in abstract form, and that the author has full power to make this grant. If portions of the article have been published previously, then the author warrants that permission has been obtained from the copyright holder and the author will submit a copy of the permission release with this copyright transfer form.
SON shall claim no proprietary right other than copyright. Authors and coauthors retain the right to revise, adapt, modify, or otherwise use all or part of the article in future works of the author(s), such as press releases, lectures, and reviews, provided that all such use is for the personal noncommercial benefit of the author(s). All patent rights are retained by the author(s).