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Community and cultivation analysis of arsenite oxidizing biofilms at Hot Creek

Salmassi, Tina M. and Walker, Jeffrey J. and Newman, Dianne K. and Leadbetter, Jared R. and Pace, Norman R. and Hering, Janet G. (2006) Community and cultivation analysis of arsenite oxidizing biofilms at Hot Creek. Environmental Microbiology, 8 (1). pp. 50-59. ISSN 1462-2912. doi:10.1111/j.1462-2920.2005.00862.x.

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At Hot Creek in California, geothermally derived arsenite is rapidly oxidized to arsenate. This process is mediated by microorganisms colonizing the surfaces of submerged aquatic macrophytes in the creek. Here we describe a multifaceted approach to characterizing this biofilm community and its activity. Molecular techniques were used to describe the community as a function of 16S-rRNA gene diversity. Cultivation-based strategies were used to enumerate and isolate three novel arsenite oxidizers, strains YED1-18, YED6-4 and YED6-21. All three strains are β-Proteobacteria, of the genus Hydrogenophaga. Because these strains were isolated from the highest (i.e. million-fold) dilutions of disrupted biofilm suspensions, they represent the most numerically significant arsenite oxidizers recovered from this community. One clone (Hot Creek Clone 44) obtained from an inventory of the 16S rDNA sequence diversity present in the biofilm was found to be 99.6% identical to the 16S rDNA sequence of the isolate YED6-21. On the basis of most probable number (MPN) analyses, arsenite-oxidizing bacteria were found to account for 6–56% of the cultivated members of the community. Using MPN values, we could estimate an upper bound on the value of V_(max) for the community of 1 × 10^(−9)µmole arsenite min^(−1) cell^(−1). This estimate represents the first normalization of arsenite oxidation rates to MPN cell densities for a microbial community in a field incubation experiment.

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Newman, Dianne K.0000-0003-1647-1918
Leadbetter, Jared R.0000-0002-7033-0844
Additional Information:© 2005 Society for Applied Microbiology and Blackwell Publishing Ltd. Received 17 December, 2004; revised 2 May, 2005; accepted 3 May, 2005. Article first published online: 25 Jul. 2005. The authors would like to acknowledge Dr Crist Khachikian at Cal State LA and Davin Malasarn at Caltech for assistance with sample collection. This work was funded in part by the National Science Foundation (EAR-9807662).
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Record Number:CaltechAUTHORS:20130415-132151408
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Official Citation:Salmassi, T. M., Walker, J. J., Newman, D. K., Leadbetter, J. R., Pace, N. R. and Hering, J. G. (2006), Community and cultivation analysis of arsenite oxidizing biofilms at Hot Creek. Environmental Microbiology, 8: 50–59. doi: 10.1111/j.1462-2920.2005.00862.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37943
Deposited By: Tony Diaz
Deposited On:17 Apr 2013 18:13
Last Modified:09 Nov 2021 23:32

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