Browsing by Author "Barua, Sutapa"

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Metagenomic insights into evolution of a heavy metal-contaminated groundwater microbial community
(2010-02) Hemme, C. L.; Deng, Ye; Gentry, Terry J.; Fields, Matthew W.; Wu, Liyou; Barua, Sutapa; Barry, Kerrie; Tringe, Susannah G.; Watson, David B.; He, Zhili; Hazen, Terry C.; Tiedje, J. M.; Rubin, E. M.; Zhou, Jizhong
Understanding adaptation of biological communities to environmental change is a central issue in ecology and evolution. Metagenomic analysis of a stressed groundwater microbial community reveals that prolonged exposure to high concentrations of heavy metals, nitric acid and organic solvents (B50 years) has resulted in a massive decrease in species and allelic diversity as well as a significant loss of metabolic diversity. Although the surviving microbial community possesses all metabolic pathways necessary for survival and growth in such an extreme environment, its structure is very simple, primarily composed of clonal denitrifying c- and b-proteobacterial populations. The resulting community is overabundant in key genes conferring resistance to specific stresses including nitrate, heavy metals and acetone. Evolutionary analysis indicates that lateral gene transfer could have a key function in rapid response and adaptation to environmental contamination. The results presented in this study have important implications in understanding, assessing and predicting the impacts of human-induced activities on microbial communities ranging from human health to agriculture to environmental management, and their responses to environmental changes.
Microbial diversity and zinc toxicity to Pseudomonas sp. from Coeur d'Alene River sediment
(Montana State University - Bozeman, College of Engineering, 2007) Barua, Sutapa; Chairperson, Graduate Committee: Brent M. Peyton
Coeur d'Alene River (CDAR) in northern Idaho is one of the metal contaminated rivers in US. The sediments of the river are enriched with As, Cd, Cu, Pb, and Zn which are toxic metals to humans and animals. It is hypothesized that microorganisms living in this river sediment can remove the metals and thus detoxify their environment. The objective of this work is to investigate the microbial communities existing in CDAR sediment using 16S ribosomal RNA (rRNA) gene sequencing and 16S rRNA gene microarray (PhyloChip) analysis. According to our phylogenetic analysis, the CDAR clones fell into 13 distinct phylogenetic classes including 2 environmental samples, 1 uncultured bacterium, and an unclassified Chloroflexi. The major representative genera found were Thiobacillus (7 of 91), Azoarcus (7/91), Acidobacterium (6/91), Burkholderia (5/91), Flavobacterium (5/91) and Janthinobacterium (5/91). PhyloChip data showed the presence of 1551 operational taxonomic units (OTUs). 97% of the clone library sequences matched at various taxonomic levels with the microarray results.