Isolation and physiological characterization of twonovel, piezophilic, thermophilic chemolithoautotrophsfrom a deep-sea hydrothermal vent chimney

摘要

Two novel, thermophilic piezophiles, capable ofchemolithoautotrophic growth, are successfully cul-tivated and isolated from a black smoker chimney atthe TAG field (Mid Atlantic Ridge: MAR) by usinga piezophilic cultivation technique. Both strains(strains 106 and 108) represent dominant cultivatedpopulations of the microbial communities in thechimney surface habitat. Strain 106 represents typi-cally thin, long spiral cells under the piezophilicgrowth condition but short bent cells under thenon-piezophilic condition. It is a strictly chemolitho-autotrophic gammaproteobacterium using reducedsulfur compounds as the electron donors, and nitrateand 02 as the electron acceptors. Based on the 16SrRNA gene sequence, strain 106 would represent anovel genus of the previously uncultivated group(Symbiont Group I; a potentially novel family) withinthe Gammaproteobacteria, and Thioprofundumlithotrophica gen. nov., sp. nov. is proposed. Strain108 is a short, oval rod at any of the growth pressures.It is a facultative chemoautotroph, capable of bothchemolithoautotrophic growth with H2 and S oxida-tions and organotrophic growth with complexorganics or organic acids using nitrate and 02 asthe electron acceptors. The chemolithoautotrophicgrowth is strictly piezophilic and under the organ-otrophic growth condition, it grows at conventionalpressures (0.1 MPa). Strain 108 is phylogenetically