FORMATION OF METHYL MERCURY BY BACTERIA
FORMATION OF METHYL MERCURY BY BACTERIA
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DOI：
10.1128/aem.30.3.424-432.1975
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发表时间：
1975-01-01
期刊：
影响因子：
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通讯作者：
NOYES, OR
中科院分区：
文献类型：
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作者：
HAMDY, MK;NOYES, OR
从美国格鲁吉亚州萨凡纳河沉积物中分离到23株耐汞菌，其中14株为革兰氏阴性短杆菌，属于埃希氏菌属和肠杆菌属，6株为革兰氏阳性球菌（3株为葡萄球菌属）。和3种链球菌属）。3株为芽孢杆菌。大肠杆菌、肠杆菌和芽孢杆菌对Hg 2+的耐药性均高于葡萄球菌和链球菌。使用系列稀释和浓度梯度琼脂平板技术进行的适应表明，可以从鉴定为产气肠杆菌的亲本培养物中选择出抗Hg 2+菌株。该培养物耐受1200 μ g Hg 2 +/ml培养基并从HgCl 2产生甲基汞，但不能将Hg 2+转化为挥发性元素汞（Hg 0）。在恒定通气下（即，浸没培养）中，形成的甲基汞比不通气的情况略多。甲基汞的生产是循环的性质，略有下降，如果DL-同型半胱氨酸存在于媒体，但增加了甲基钴胺素。甲基汞的细菌产生可能是对汞剂的抵抗和解毒的一种手段，其中无机Hg 2+转化为有机形式并分泌到环境中。
Twenty-three Hg2+-resistant cultures were isolated from sediment of the Savannah River in Georgia (USA); of these, 14 were gram-negative short rods belonging to the genera Escherichia and Enterobacter, 6 were gram-positive cocci (3 Staphylococcus spp. and 3 Streptococcus spp.) and 3 were Bacillus spp. All the Escherichia, Enterobacter and the Bacillus strain were more resistant to Hg2+ than the strains of staphylococci and streptococci. Adaptation using serial dilutions and concentration gradient agar plate techniques showed that it was possible to select a Hg2+-resistant strain from a parent culture identified as Enterobacter aerogenes. This culture resisted 1200 .mu.g of Hg2+/ml of medium and produced methyl mercury from HgCl2, but was unable to convert Hg2+ to volatile elemental mercury (Hg0). Under constant aeration (i.e., submerged culture), slightly more methyl mercury was formed than in the absence of aeration. Production of methyl mercury was cyclic in nature and slightly decreased if DL-homocysteine was present in media, but increased with methylcobalamine. The bacterial production of methyl mercury may be a means of resistance and detoxification against mercurials in which inorganic Hg2+ is converted to organic form and secreted into the environment.