Bacterial Community in the Lake Water Spiked with Dimethylarsenic Acid Estimated by PCR−DGGE Analysis

Abstract

 In aquatic environments, the bacterial decomposition of organoarsenic compounds, such as dimethylarsinic acid, was important for evaluation of the dynamics of each arsenic species. The process of the arsenic cycle has been investigated by many researchers. For investigation of the bacterial decomposition activity of organoarsenic compounds in the lake water, dimethylarsinic acid ((CH₃)₂AsO(OH); DMAA) was added at final concentrations of 1 μmol⁄l and 0.05 μmol⁄l to the sample water. In addition, the sample was cultivated in an anaerobic or aerobic condition and light or dark condition. The DMAA was remarkably decomposed at the 30th day only in an anaerobic and dark condition. Denaturing gradient gel electrophoresis (DGGE) was performed after DNA extraction from the sample water. Two DNA extraction methods were compared to obtain more useful DNA for phylogenetic analysis.Sequence analysis of DGGE bands showed that beta-proteobacteria subdivision was predominant member in the sample water at the 30th day after the DMAA addition. Therefore, the members of beta-proteobacteria subdivision would decompose organoarsenic compounds.