Novel anaerobic thermophilic bacteria
Wagner, Isaac David
MetadataShow full item record
Thermophilic anaerobic prokaryotes are of interest from basic and applied scientific perspectives. Novel anaerobic thermophilic taxa are herein described are Caldanaerovirga acetigignens gen. nov., sp. nov.; and Thermoanaerobacter uzonensis sp. nov. Novel taxa descriptions co-authored were: Thermosediminibacter oceani gen. nov., sp. nov and Thermosediminibacter litoriperuensis sp. nov; Caldicoprobacter oshimai gen. nov., sp. nov. More than 220 anaerobic thermophilic isolates were obtained from samples collected from 11 geothermal springs within the Uzon Caldera, Geyser Valley, and Mutnovsky Volcano regions of the Kamchatka Peninsula, Russian Far East. Most strains were phylogenetically related to Thermoanaerobacter uzonensis JW/IW010T, while some were phylogenetically related to Thermoanaerobacter siderophilus SR4T. Eight protein coding genes, gyrB, lepA, leuS, pyrG, recA, recG, rplB, and rpoB, were amplified and sequenced from these isolates to describe and elucidate the intraspecies heterogeneity, α- and β-diversity patterns, and the spatial and physicochemical correlations to the observed genetic variation. All protein coding genes within the T. uzonensis isolates were found to be polymorphic, although the type (i.e., synonymous/ nonsynonymous substitutions) and quantity of the variation differed between gene sequence sets. The most applicable species concept for T. uzonensis must consider metapopulation/ subpopulation dynamics and acknowledge that physiological characteristics (e.g., sporulation) likely influences the flux of genetic information between subpopulations. Spatial variation in the distribution of T. uzonensis isolates was observed. Evaluation of T. uzonensis α-diversity revealed a range of genetic variation within a single geothermal spring. β-diversity measurements revealed that while most of the molecular variance came from inter-regional comparisons, high diversity measures between populations within a region were also observed. Between geothermal springs from different regions, T. uzonensis genetic divergence was correlated with an increase in spatial separation. However, the trend was not observed when only the isolates between the geothermal springs within a region were considered. When 27 physicochemical properties from four geothermal springs in the Uzon Caldera were matched to a corresponding biological distribution pattern, high rank correlation values, calculated as Spearman's ρ, were observed. Together, these analyses suggest that the spatial variation of T. uzonensis was influenced by both environmental differences and spatial separation.