Open AccessThauera selenatis gen. nov., sp. nov., a Member of the Beta Subclass of Proteobacteria with a Novel Type of Anaerobic Respiration
Author(s) -
Joan M. Macy,
Sabine Rech,
Georg Auling,
Mattias Dorsch,
Erko Stackebrandt,
Lindsay I. Sly
Publication year - 1993
Publication title -
international journal of systematic bacteriology
Language(s) - English
Resource type - Journals
eISSN - 1070-6259
pISSN - 0020-7713
DOI - 10.1099/00207713-43-1-135
Subject(s) - strain (injury) , proteobacteria , biology , genus , 16s ribosomal rna , microbiology and biotechnology , bacteria , botany , genetics , anatomy
A recently isolated, selenate-respiring microorganism (strain AXT [T = type strain]) was classified by using a polyphasic approach in which both genotypic and phenotypic characteristics were determined. Strain AXT is a motile, gram-negative, rod-shaped organism with a single polar flagellum. On the basis of phenotypic characteristics, this organism can be classified as a Pseudomonas sp. However, a comparison of the 16S rRNA sequence of strain AXT with the sequences of other organisms indicated that strain AXT is most similar to members of the beta subclass (level of similarity, 86.8%) rather than to members of the gamma subclass (level of similarity, 80.2%) of the Proteobacteria. The presence of the specific polyamine 2-hydroxyputrescine and the presence of a ubiquinone with eight isoprenoid units in the side chain (ubiquinone Q-8) excluded strain AXT from the authentic genus Pseudomonas and allowed placement in the beta subclass of the Proteobacteria. Within the beta subclass, strain AXT is related to Iodobacter fluvatile. The phylogenetic distance (level of similarity, less than 90%), as well as a lack of common phenotypic characteristics between these organisms, prevents classification of strain AXT as a member of the genus Iodobacter. In addition, strain AXT possesses a unique mechanism for anaerobic respiration, which allows it to utilize selenate as an electron acceptor without interference by nitrate. Therefore, we propose that strain AXT should be the first member of a new genus and species, Thauera selenatis.