A Novel Lineage of Proteobacteria Involved in Formation of Marine Fe-Oxidizing Microbial Mat CommunitiesReportar como inadecuado

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For decades it has been recognized that neutrophilic Fe-oxidizing bacteria FeOB are associated with hydrothermal venting of FeII-rich fluids associated with seamounts in the world-s oceans. The evidence was based almost entirely on the mineralogical remains of the microbes, which themselves had neither been brought into culture or been assigned to a specific phylogenetic clade. We have used both cultivation and cultivation-independent techniques to study Fe-rich microbial mats associated with hydrothermal venting at Loihi Seamount, a submarine volcano.

Methodology-Principle Findings

Using gradient enrichment techniques, two iron-oxidizing bacteria, strains PV-1 and JV-1, were isolated. Chemolithotrophic growth was observed under microaerobic conditions; FeII and Fe0 were the only energy sources that supported growth. Both strains produced filamentous stalk-like structures composed of multiple nanometer sized fibrils of Fe-oxyhydroxide. These were consistent with mineralogical structures found in the iron mats. Phylogenetic analysis of the small subunit SSU rRNA gene demonstrated that strains PV-1 and JV-1 were identical and formed a monophyletic group deeply rooted within the Proteobacteria. The most similar sequence 85.3% similarity from a cultivated isolate came from Methylophaga marina. Phylogenetic analysis of the RecA and GyrB protein sequences confirmed that these strains are distantly related to other members of the Proteobacteria. A cultivation-independent analysis of the SSU rRNA gene by terminal-restriction fragment T-RF profiling showed that this phylotype was most common in a variety of microbial mats collected at different times and locations at Loihi.


On the basis of phylogenetic and physiological data, it is proposed that isolate PV-1T  = ATCC BAA-1019: JCM 14766 represents the type strain of a novel species in a new genus, Mariprofundus ferrooxydans gen. nov., sp. nov. Furthermore, the strain is the first cultured representative of a new candidatus class of the Proteobacteria that is widely distributed in deep-sea environments, Candidatus ζ zeta-Proteobacteria cl. nov.

Autor: David Emerson , Jeremy A. Rentz, Timothy G. Lilburn, Richard E. Davis, Henry Aldrich, Clara Chan, Craig L. Moyer

Fuente: http://plos.srce.hr/


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