Cobalt Uptake and Resistance to Trace Metals in Comamonas testosteroni Isolated From a Heavy-Metal Contaminated Site in the Zambian Copperbelt.

Autor: Staniland, Sarah, Coppock, Michael, Tuffin, Marla, van Zyl, Lonnie, Roychoudhury, AlakendraN., Cowan, Donald
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Zdroj: Geomicrobiology Journal; Dec2010, Vol. 27 Issue 8, p656-668, 13p, 1 Black and White Photograph, 1 Diagram, 3 Charts, 4 Graphs, 1 Map
Abstrakt: A biogeochemical study of a polluted wetland site in Kitwe, Zambia shows high concentration of trace metals (e.g., > 25 and ≈ 2 fold higher than the Eco-toxic threshold values of copper and cobalt, respectively) with many sequestered with the sediment organic phase. Depth profiles in surface sediments suggest trace metal cycling between porewater and solid phases, including that of cobalt. This study documents a bacterium displaying resistance to, and accumulation of cobalt, and that cobalt has a positive effect on growth. The isolate was enriched from the microbial community and identified using 16S rRNA gene sequence analysis as a strain of Comamonas testosteroni (designated C. testosteroni TDKW). Improved growth of C. testosteroni TDKW was seen with the addition of up to 200 μM cobalt (optimal growth ca. 100 μM), while concentrations above 4 mM completely inhibited growth. C. testosteroni TDKW also exhibited resistance to high concentrations of iron and manganese, but showed limited resistance to copper or nickel. Further analysis revealed cellular cobalt accumulation and the presence of heavy-metal resistance genes, tentatively suggesting that this organism could contribute to in situ biological cycling of cobalt in mineral contaminated aquatic systems. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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