Bogdanova E S, Mindlin S Z, Pakrová E, Kocur M, Rouch D A
Institute of Molecular Genetics, Russian Academy of Sciences, Moscow.
FEMS Microbiol Lett. 1992 Oct 1;76(1-2):95-100. doi: 10.1016/0378-1097(92)90370-4.
According to existing data, mercury resistance operons (mer operons) are in general thought to be rare in bacteria, other than those from mercury-contaminated sites. We have found that a high proportion of strains in environmental isolates of Gram-positive bacteria express mercuric reductase (MerA protein): the majority of these strains are apparently sensitive to mercury. The expression of MerA was also inducible in all cases. These results imply the presence of phenotypically cryptic mer resistance operons, with both the merA (mercuric reductase) and merR (regulatory) genes still present, but the possible absence of the transport function required to complete the resistance mechanism. This indicates that mer operons or parts thereof are more widely spread in nature than is suggested by the frequency of mercury-resistant bacteria.
根据现有数据，除了来自汞污染场地的细菌外，一般认为细菌中的汞抗性操纵子（mer操纵子）很少见。我们发现革兰氏阳性菌环境分离株中有很大比例的菌株表达汞还原酶（MerA蛋白）：这些菌株中的大多数显然对汞敏感。在所有情况下，MerA的表达也都是可诱导的。这些结果表明存在表型隐性的mer抗性操纵子，其中merA（汞还原酶）和merR（调节）基因仍然存在，但可能缺少完成抗性机制所需的转运功能。这表明mer操纵子或其部分在自然界中的分布比耐汞细菌的频率所显示的更为广泛。
