Biotransformation of se-methylselenocysteine into volatile selenocompounds by bacteria isolated from rat gut microflora

Abstract

Selenium (Se) is an essential micronutrient that exists in various chemical forms in nature. Because of this property, animals must metabolize diverse Se species to utilize them as selenoproteins. Although gut microflora is suggested to play a role in Se metabolism in host animal, the biotransformation of Se by gut microflora in animal gut is not fully understood. In this study, we isolated Morganella morganii from rat feces under the condition that Se-methylseleno-L-cysteine (MeSeCys), one of the major Se sources in vegetables, was present in excess. Then, we examined the biotransformation of MeSeCys by M. morganii. Two volatile selenocompounds, dimethyldiselenide (DMDSe) and dimethylselenide (DMSe), were detected by GC–MS in the headspace of M. morganii culture. We speculate that M. morganii cleaved off the methylselenyl group from MeSeCys. Taken together, we conclude that gut microflora plays a role in the biotransformation of MeSeCys, and seems to support efficient metabolism in animals.

Keywords

• Selenium
• Dimethyldiselenide
• Dimethylselenide
• M. morganii
• GC–MS
• Gut microflora