Sierra Nevada Aquatic Research Laboratory

24 Oct, 12 PM - 26 Oct, 02 AM

Microbe-mediated redox reactions of arsenic play a critical role in arsenic contamination of water. Arsenate reduction by microbes generates more toxic and hydrologically more mobile arsenite. Other microbes have the ability to oxidize arsenite back to arsenate using a membrane associate oxidase encoded by the aroA gene. This oxidation is coupled to microbial respiration and is believed to be a defense mechanism against the toxicity of arsenite, because arsenate is less toxic to microbes. Because arsenate preferentially partitions into solid phases, arsenite oxidation might be a natural process that removes toxic arsenite from contaminated water. Microbe-mediate arsenic redox reactions therefore have geological impacts on drinking water quality. However, microbial arsenite oxidation has not been fully explored under in situ conditions. The principle aim of this proposal is to develop the aroA gene as a molecular marker to investigate the impact of arsenite oxidation on water quality. The specific objectives are (1) to isolate representative arsenite oxidizing microbes from Hot Creek, a California tributary of the Los Angeles Aqueduct in which there is significant biological arsenite oxidation, (2) to develop a quantitative polymerase chain reaction (PCR) assay based on the aroA sequence to detect arsenite-oxidizing microbes, and (3) to use the aroA PCR detection assay to investigate the abundance, diversity, and expression of aroA in water and sediment samples collected from Hot Creek that vary in arsenite concentrations. Developing an aroA detection assay will allow monitoring for arsenic contamination at the biological level. This detection system can be broadly applied to monitor arsenite oxidation in industrial waste sites and in other locales affected by arsenic-contaminated groundwater, namely Bangladesh and other East Asian countries.

Visit #8301 @Sierra Nevada Aquatic Research Laboratory

Approved

Under Project # 5884 | Research

Hot Creek Microbial Ecology

faculty - University of California, Santa Cruz

Reservation Members(s)

Chad Saltikov Oct 24 - 26, 2005 (3 days)
Chad Saltikov Oct 24 - 26, 2005 (3 days)
Chad Saltikov Oct 24 - 26, 2005 (3 days)

Reserve Resources(s) | Create Invoice

Dorm 3 Oct 24 - 26, 2005