Analysis Of Microbial Community In Arsenic Polluted Environment And Characteristics Of Bacillus Sp.JH-5-4

Arsenic gold mine tailings accumulation often lead to the release of arsenic(As)contaminants into the surrounding environments,which has become in a global concern.Recent studies have demonstrated microorganisms playing an important role in As cycle,whereas the influences of As on bacterial communities remains unclear.To reveal the influences of As on diversity and variation of bacterial communities and the arsenic-tolerance potential of bacterial communities under As contaminants pressure,the farmland soil and river sediment samples were collected according to distance from tailings in Dandong,Liaoning,China.The structure and distribution of bacterial communities were analyzed using high-throughput sequencing.The As resistance gene arsB or ACR3 pump As(III)out of the cell to resist As toxicity.We studied the abundance,distribution and phylogeny of arsB and ACR3 by using PCR-based clone libraries and Quantitative PCR.The main results of this study were as follows:(1)As pollution reduces the diversity of microbial communities.At the level of Phylum,the proportion of Proteobacteria increased.At the Genes level.The dominant Species in the polluted soil sediments were Sulfuricurvum,and the dominant Species in the non-polluted environment were Candidatus Solibacter(Acidobacteria).The dominant Species in the heavily polluted sediments of the river are Clostridium,The dominant Species in the slightly polluted sediments of the river are Comamonadaceae.(2)ArsB andACR3 genes are closely related to the main strains of β-mycobacteria and γ-strain bacteria,arsB gene is mainly distributed in river sediment samples,and the phylogenetic relationship of Species is greatly affected by geographical location.The ACR3 gene is distributed in farmland sediments and widely distributed in all samples and the diversity was high.ACR3 is closely related to the Thiobacillus,and the effects of arsenic and sulfur on microbes are interrelated(3)One arsenic-resistant strains(Bacillus sp.JH-5-4)was isolated.This strain contain arsB and ACR3 gene.The two genes were obtained from the different strains,The arsenic resistance gene can horizontally transferred between microorganisms,The pH of the culture medium was increased during the culture.The copy number of the arsB gene was more than 1000 times higher than that of the ACR3 gene.The copy number of arsB and ACR3 gene in culture system increased with the increase of As concentration.The addition of Lincomycin to the culture system will promote the increase of copy number of arsB and ACR3 genes.Except culture with Lincomycin concentration of 10μL.