Combs G F, Garbisu C, Yee B C, Yee A, Carlson D E, Smith N R, Magyarosy A C, Leighton T, Buchanan B B
Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
Biol Trace Elem Res. 1996 Jun;52(3):209-25. doi: 10.1007/BF02789163.
The bioavailability of selenium (Se) was determined in bacterial strains that reduce selenite to red elemental Se (SeO). A laboratory strain of Bacillus subtilis and a bacterial rod isolated from soil in the vicinity of the Kesterson Reservoir, San Joaquin Valley, CA, (Microbacterium arborescens) were cultured in the presence of 1 mM sodium selenite (Na2SeO3). After harvest, the washed, lyophilized B. Subtilis and M. arborescens samples contained 2.62 and 4.23% total Se, respectively, which was shown to consist, within error, entirely of SeO. These preparations were fed to chicks as supplements to a low-Se, vitamin E-free diet. Three experiments showed that the Se in both bacteria had bioavailabilities of approx 2% that of selenite. A fourth experiment revealed that gray SeO had a bioavailability of 2% of selenite, but that the bioavailability of red SeO depended on the way it was prepared (by reduction of selenite). When glutathione was the reductant, bioavailability resembled that of gray SeO and bacterial Se; when ascorbate was the reductant, bioavailability was twice that level (3-4%). These findings suggest that aerobic bacteria such as B. subtilis and M. arborescens may be useful for the bioremediation of Se-contaminated sites, i.e., by converting selenite to a form of Se with very low bioavailability.
在能将亚硒酸盐还原为红色元素硒（SeO）的细菌菌株中测定了硒（Se）的生物利用度。在1 mM亚硒酸钠（Na2SeO3）存在的情况下，培养了枯草芽孢杆菌的实验室菌株以及从加利福尼亚州圣华金谷凯斯特森水库附近土壤中分离出的一种杆菌（树木微杆菌）。收获后，洗涤并冻干的枯草芽孢杆菌和树木微杆菌样品分别含有2.62%和4.23%的总硒，结果表明在误差范围内，这些硒全部由SeO组成。将这些制剂作为低硒、无维生素E饮食的补充剂喂给雏鸡。三项实验表明，两种细菌中的硒生物利用度约为亚硒酸盐的2%。第四项实验表明，灰色SeO的生物利用度为亚硒酸盐的2%，但红色SeO的生物利用度取决于其制备方式（通过亚硒酸盐还原）。当谷胱甘肽作为还原剂时，生物利用度与灰色SeO和细菌硒相似；当抗坏血酸作为还原剂时，生物利用度是该水平的两倍（3 - 4%）。这些发现表明，枯草芽孢杆菌和树木微杆菌等需氧细菌可能有助于对受硒污染的场地进行生物修复，即通过将亚硒酸盐转化为生物利用度非常低的硒形式。
