Dissimilatory Arsenate and Sulfate Reduction in Sediments of Two Hypersaline, Arsenic-Rich Soda Lakes: Mono and Searles Lakes, California
| Autor: | J. N. Murphy, Shelley E. Hoeft, Ronald S. Oremland, Chad W. Saltikov, Sukkyun Han, Brian Lanoil, Laurence G. Miller, Thomas R. Kulp |
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| Rok vydání: | 2006 |
| Předmět: |
Geologic Sediments
Molecular Sequence Data chemistry.chemical_element Mineralogy Fresh Water Applied Microbiology and Biotechnology chemistry.chemical_compound Sulfate Ecosystem Arsenic geography Bacteria Ecology Sulfates Soda Lakes Arsenate Sediment 16S ribosomal RNA Geomicrobiology Salinity chemistry Environmental chemistry geography.geographical_feature Arsenates Water Microbiology Oxidation-Reduction Temperature gradient gel electrophoresis Food Science Biotechnology |
| Zdroj: | Applied and Environmental Microbiology. 72:6514-6526 |
| ISSN: | 1098-5336 0099-2240 |
| Popis: | A radioisotope method was devised to study bacterial respiratory reduction of arsenate in sediments. The following two arsenic-rich soda lakes in California were chosen for comparison on the basis of their different salinities: Mono Lake (∼90 g/liter) and Searles Lake (∼340 g/liter). Profiles of arsenate reduction and sulfate reduction were constructed for both lakes. Reduction of [ 73 As]arsenate occurred at all depth intervals in the cores from Mono Lake (rate constant [ k ] = 0.103 to 0.04 h −1 ) and Searles Lake ( k = 0.012 to 0.002 h −1 ), and the highest activities occurred in the top sections of each core. In contrast, [ 35 S]sulfate reduction was measurable in Mono Lake ( k = 7.6 ×10 4 to 3.2 × 10 −6 h −1 ) but not in Searles Lake. Sediment DNA was extracted, PCR amplified, and separated by denaturing gradient gel electrophoresis (DGGE) to obtain phylogenetic markers (i.e., 16S rRNA genes) and a partial functional gene for dissimilatory arsenate reduction ( arrA ). The amplified arrA gene product showed a similar trend in both lakes; the signal was strongest in surface sediments and decreased to undetectable levels deeper in the sediments. More arrA gene signal was observed in Mono Lake and was detectable at a greater depth, despite the higher arsenate reduction activity observed in Searles Lake. A partial sequence (about 900 bp) was obtained for a clone (SLAS-3) that matched the dominant DGGE band found in deeper parts of the Searles Lake sample (below 3 cm), and this clone was found to be closely related to SLAS-1, a novel extremophilic arsenate respirer previously cultivated from Searles Lake. |
| Databáze: | OpenAIRE |
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