Rochelle Paul A, Wetherbee Mary K, Olson Betty H
Environmental Analysis, Social Ecology, University of California, Irvine, California 92717.
Appl Environ Microbiol. 1991 Jun;57(6):1581-1589. doi: 10.1128/aem.57.6.1581-1589.1991.
The distribution of DNA sequences homologous with three mer genes was determined in unselected and mercury-resistant water and sediment isolates. The maximum proportions of unselected bacterial isolates containing DNA hybridizing with the 358merA, 358merB, and 501merR probes, derived from gram-negative organisms, were 93.8, 21, and 100%, respectively. Up to 53.3% of mercury chloride-resistant isolates and 54% of methylmercury hydroxide-resistant isolates did not contain DNA homologous with 358merA or 358merB, respectively. Hybridizations performed at high and low stringencies demonstrated that divergence of the merA gene accounted for many of the mercury-resistant but probe-negative isolates. Sixteen mercury-resistant Bacillus spp. isolated from the least contaminated site all contained DNA homologous with 258merA, originally from a gram-positive organism, but only four hybridized weakly with 358merA. The results demonstrate the wide distribution of mercury resistance genes but, because of the diversity of genetic determinants, highlight the importance of using multiple detection techniques and gene probes derived from a variety of origins for such studies.
在未经筛选的以及耐汞的水和沉积物分离菌株中，测定了与三种汞抗性基因（mer基因）同源的DNA序列的分布情况。来自革兰氏阴性菌的、与358merA、358merB和501merR探针杂交的未筛选细菌分离株的最大比例分别为93.8%、21%和100%。分别有高达53.3%的耐氯化汞分离株和54%的耐氢氧化甲基汞分离株不含有与358merA或358merB同源的DNA。在高严谨度和低严谨度下进行的杂交表明，merA基因存在差异可以解释许多耐汞但探针阴性的分离株。从污染程度最低的地点分离出的16株耐汞芽孢杆菌属菌株均含有与最初来自革兰氏阳性菌的258merA同源的DNA，但只有4株与358merA弱杂交。结果表明汞抗性基因分布广泛，但由于遗传决定因素的多样性，突出了在这类研究中使用多种检测技术和源自多种来源基因探针的重要性。
