Murata Tomoyoshi
Water & Soil Environment Division, National Institute for Environmental Studies, Japan.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2006;41(2):161-72. doi: 10.1080/10934520500349276.
The present study was undertaken to obtain information about the effects of Bi contamination on soil microbial growth and activity using a series of Bi complexes with thiol compounds, including mercaptoethanol, thioglycerol, mercaptoethylamine, thioglycolic acid, thiomallic acid, reduced glutathione, 2-mercaptopropionic acid, and L-cysteine. We found that Bi complexes with mercaptoethanol, thioglycerol, and mercaptoethylamine, all of which showed lipophilicity, markedly inhibited bacterial growth in 1/10 TSB liquid media in both Eutric Cambisol (brown forest soil) and Eutric Fluvisol (brown lowland soil), with relative CFU of less than 2% at 50 micro M Bi and 6% at 25 micro M Bi. However, none of the Bi-thiols, including Highly lipophilic complexes, at 200 micro M Bi in rosebengal agar medium inhibited fungal growth, possibly because fungi have a metabolic system that protects against Bi uptake or detoxifies Bi compounds. When soil was contaminated experimentally with Bi-thiol, these complexes suppressed soil dehydrogenase activity, particularly in brown forest soil, which contains large amounts of easily decomposable organic matter. These results indicate that the effects of Bi on soil microbes may depend on mutual reactions with organic matter in the environment.
本研究旨在通过一系列含硫醇化合物的铋配合物，包括巯基乙醇、硫代甘油、巯基乙胺、巯基乙酸、硫代苹果酸、还原型谷胱甘肽、2-巯基丙酸和L-半胱氨酸，获取有关铋污染对土壤微生物生长和活性影响的信息。我们发现，铋与巯基乙醇、硫代甘油和巯基乙胺形成的配合物均表现出亲脂性，在潜育性始成土（棕色森林土）和潜育性潮土（棕色低地土）的1/10胰蛋白胨大豆肉汤液体培养基中均显著抑制细菌生长，在50微摩尔/升铋时相对菌落形成单位小于2%，在25微摩尔/升铋时为6%。然而，在孟加拉红琼脂培养基中，200微摩尔/升铋的所有铋硫醇配合物，包括高度亲脂性的配合物，均未抑制真菌生长，这可能是因为真菌具有防止铋吸收或使铋化合物解毒的代谢系统。当用铋硫醇对土壤进行实验污染时，这些配合物会抑制土壤脱氢酶活性，尤其是在含有大量易分解有机物的棕色森林土中。这些结果表明，铋对土壤微生物的影响可能取决于其与环境中有机物的相互反应。
