INVESTIGADORES
DIONISI Hebe Monica
congresos y reuniones científicas
Título:
Arsenic Contamination and Sulfur-Reducing Bacteria in Groundwater from Bangladesh
Autor/es:
SCHOLZ, M.; DIONISI, H.; SANSEVERINO, J.; SAUNDERS, J.; SAYLER, G.S.
Lugar:
Orlando, Florida, EEUU
Reunión:
Congreso; 106th General Meeting American Society for Microbiology; 2006
Institución organizadora:
American Society for Microbiology
Resumen:
Arsenic contamination of the groundwater in Bangladesh is considered the largest mass poisoning in history. Recent studies have shown links between both iron and sulfur-reducing bacteria and arsenic mobilization in groundwater in the United States and Bangladesh. Linkage between anaerobic microbial respiration by use of arsenic respiratory reductase genes (Arr cassette) and increased arsenic levels has also been illustrated. Culture-independent molecular techniques were used to characterize bacterial populations capable of affecting As solubility in Bangladesh. Groundwater samples from Bangladesh, with high (58 ppb) and low arsenic concentrations (3.5 ppb) were analyzed via 16s rRNA screening, for microbial community distribution. Functional genetic studies were performed to test for and classify genes responsible for dissimilatory sulfur reduction (dsrAB genes) and the Arr gene cassette. 16S rRNA gene libraries indicated the presence of Desulfobacteria at a significant level (12% of overall library) in the high As concentration sample, while no Desulfobacteria species were identified at low As levels. At the lower concentration, a 4-fold increase in the number of Pseudomonas species was observed relative to the high As contaminated sample. Functional gene analysis for the dsrAB genes, instrumental in dissimilatory sulfur reduction, show diverse individual genotypes in the library at high arsenic content, but were undetectable at low As levels. Preliminary data indicate increased gene copy numbers of the Arr cassette in samples higher in arsenic. These data support the theory that the presence of sulfur reducing bacteria and bacteria containing the Arr gene cassette are positively correlated to arsenic concentrations in groundwater in Bangladesh.
