Zelibor J L, Doughten M W, Grimes D J, Colwell R R
Department of Microbiology, University of Maryland, College Park 20742.
Appl Environ Microbiol. 1987 Dec;53(12):2929-34. doi: 10.1128/aem.53.12.2929-2934.1987.
Direct viable counting of metal-resistant bacteria (DVCMR) has been found to be useful in both enumerating and differentiating metal-resistant and metal-sensitive strains of bacteria. The DVCMR bioassay was used to detect effects of low and high concentrations of arsenic and arsenicals on bacterial populations in groundwater. The level of resistance of the bacterial populations to arsenate was determined by the DVCMR bioassay, and the results showed a linear correlation with the total arsenic concentrations in the monitoring well water samples; no correlation was observed by culture methods with the methods employed. Bacteria resistant to 2,000 micrograms of arsenate per ml were isolated from all monitoring well water samples studied. Strains showed similar antibiotic and heavy-metal profiles, suggesting that the arsenic was not a highly selective pressure for arsenic alone. The monitoring well water samples were amended with arsenate and nutrients to determine the biotransformation mechanisms involved. Preliminary results suggest that bacteria indigenous to the monitoring well water samples did not directly transform, i.e., precipitate or volatilize, dissolved arsenic. It was concluded that arsenic contamination of the groundwater can be monitored by the DVCMR bioassay.
已发现金属抗性细菌的直接活菌计数法（DVCMR）在计数和区分金属抗性及金属敏感细菌菌株方面都很有用。DVCMR生物测定法用于检测低浓度和高浓度砷及砷化合物对地下水中细菌种群的影响。通过DVCMR生物测定法确定细菌种群对砷酸盐的抗性水平，结果表明其与监测井水样中的总砷浓度呈线性相关；采用的培养方法未观察到相关性。从所有研究的监测井水样中分离出了对每毫升2000微克砷酸盐具有抗性的细菌。菌株显示出相似的抗生素和重金属特征，这表明砷并非仅对砷有高度选择性压力。向监测井水样中添加砷酸盐和营养物质，以确定其中涉及的生物转化机制。初步结果表明，监测井水样中的本地细菌不会直接转化，即沉淀或挥发溶解态砷。得出的结论是，可通过DVCMR生物测定法监测地下水的砷污染。
