This Article Full Text (PDF) Other Versions of this Article: AEM.01200-07v1 74/4/942    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kozubal, M. Articles by Inskeep, W. P. Search for Related Content PubMed PubMed Citation Articles by Kozubal, M. Articles by Inskeep, W. P. Agricola Articles by Kozubal, M. Articles by Inskeep, W. P.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol. doi:10.1128/AEM.01200-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Isolation and Distribution of a Novel Iron-Oxidizing Crenarchaeon from Acidic Geothermal Springs in Yellowstone National Park

Thermal Biology Institute and Department of Land Resources and Environmental Sciences, Montana State University, Bozeman MT 59717

^* To whom correspondence should be addressed. Email: binskeep{at}montana.edu.

	Abstract

Novel thermophilic Crenarchaea have been observed in Fe^III-oxide microbial mats of Yellowstone National Park (YNP); however, no definitive work has identified specific microorganisms responsible for the oxidation of Fe^II. The objectives of the current study were to isolate and characterize an Fe^II-oxidizing Sulfolobales observed in prior 16S rRNA gene surveys, and to determine the abundance and distribution of close relatives of this organism in acidic geothermal springs containing high concentrations of dissolved Fe^II. Here we report the isolation and characterization of a novel Fe^II-oxidizing thermophilic, acidophilic Metallosphaera sp. strain MK1 obtained from a well-characterized acid-sulfate-chloride geothermal spring in Norris Geyser Basin, YNP. Full-length 16S rRNA gene sequence analysis revealed that strain MK1 exhibits only 94.9-96.1% sequence similarity to other known Metallosphaera spp. and less than 89.1% similarity to known Sulfolobus spp. Strain MK1 is a facultative chemolithoautotroph with an optimum pH range of 2.0-3.0 and an optimum temperature range of 65-75 °C. Strain MK1 grows optimally on pyrite or Fe^II sorbed onto ferrihydrite, exhibiting doubling times between 10-11 hours under aerobic conditions (65 °C). The distribution and relative abundance of MK1-like 16S rRNA gene sequences was evaluated in 14 acidic geothermal springs containing Fe^III-oxide microbial mats. Highly related MK1-like 16S rRNA gene sequences (>99% sequence similarity) were consistently observed in Fe^III-oxide mats across temperatures from 55-80 °C. Quantitative PCR using Metallosphaera-specific primers confirmed that organisms highly similar to strain MK1 comprised up to 40% of the total archaeal community of selected sites. The broad distribution of highly related MK1-like 16S rRNA gene sequences in acidic Fe^III-oxide microbial mats is consistent with the observed characteristics and growth optima of Metallosphaera-like strain MK1, and emphasizes the importance of this newly described taxon in Fe^II chemolithotrophy in acidic high-temperature environments of YNP.