title: Selenomethionine biotransformation and incorporation into proteins along a simulated terrestrial food chain.
abstract: Selenium is an essential trace element in vertebrates, but there is a narrow concentration range between dietary requirement and toxicity threshold. Although a great deal is known about the biochemistry of Se from a nutritional perspective, considerably less attention has been focused on the specific biochemistry of Se as an environmental toxicant. Recent advances in hyphenated analytical techniques have provided the capability of quantifying specific chemical forms of Se in biological tissues as well as the distribution of Se among macromolecules. We applied liquid chromatography coupled to inductively coupled plasma mass spectrometryto investigate biotransformations of selenomethionine along a simulated terrestrial food chain consisting of selenomethionine exposed crickets (Acheta domesticus) fed to western fence lizards (Sceloporus occidentalis). Evidence was obtained for selenomethionine biotransformation as well as for sex-specific differences in the metabolism of Se compounds and their subsequent incorporation into proteins in the lizard. The results demonstrate the complexities involved in trophic transfer of Se due to the potential for extensive biotransformation and the species- and even sex-specific nature of these biotransformations.
authors.affiliation: The University of Georgia, P.O. Drawer E, Aiken, South Carolina 29802, Departments of Chemistry and Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA. unrine@srel.edu
authors.forename: Jason M
authors.initials: JM
authors.lastname: Unrine
authors.forename: Brian P
authors.initials: BP
authors.lastname: Jackson
authors.forename: William A
authors.initials: WA
authors.lastname: Hopkins
mesh_terms: D000818:Animals; D001711:Biotransformation; D002850:Chromatography, Gel; D005260:Female; D020387:Food Chain; D007313:Insecta / Q000378:metabolism; D008116:Lizards / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D008970:Molecular Weight; D011506:Proteins / Q000378:metabolism*; D012643:Selenium / Q000032:analysis; D012645:Selenomethionine / Q000378:metabolism*; D013455:Sulfur / Q000032:analysis
chemical_list: D011506:Proteins; D013455:Sulfur; D012645:Selenomethionine; D012643:Selenium