Microflorae on the edges of global biosphere (deep seafloor and deep subsurface) : phylogenetic and ecological approaches

本研究旨在基于16 SrRNA基因的DNA序列对深海和深次表层微生物进行系统发育分析（165 rDNA）和RuBisCO和异化亚硫酸盐还原酶（DSR）等生态相关酶的基因。从深海样品中提取大量DNA，并用于16 S rRNA、FuBisCO和DSR基因的PCR扩增。首先，深海富甲烷渗漏沉积物中的16 SrDNA显示出丰富的细菌植物群，包括硫氧化细菌和甲烷氧化细菌。这些硫自养和甲烷氧化细菌的出现证实了在富甲烷渗漏中密集的生物群落是由微生物硫营养和甲烷氧化产物支持的观点。 ...更多信息 - 海洋样品并进行了生物成因分析。基于RuBisCO的系统发育树显示了与基于16 SrDNA的系统发育树不同的聚类模式，这归因于RuBisCO基因的水平转移。厌氧RuBisCO基因在深海样品中广泛分布，表明其在深海自养生产中的重要性。硫酸盐还原中起主要作用的DSR酶基因从深海富甲烷渗漏中回收。对渗漏DSR基因的系统发育分析表明，以前未知的DSR簇可能属于细菌和细菌。DSR基因的多样性大于硫酸盐还原菌检测的16 S rDNA为基础的analysis. Similaranalyses进行了类似的分析，从深层地下收集的样品，和不同的化能自养菌和厌氧菌的发生被证明。此外，还成功地分离和培养了一些地下细菌菌株。正在研究分类、系统发育和生理特征。少

This study aimed at the phylogenetic analyses of microorganisms inhabiting deep-sea and deep subsurface based on the DNA sequences of the 16S rRNA gene (165 rDNA) and the genes for ecologically relevant enzymes such as RuBisCO and dissimilatory sulfite reductase (DSR) Samples were collected from deep seafloor sediment by manned/unmanned submersibles and from 1000 m-deep boreholes in Tono area, central Japan.Bulk DNA was extracted from the deep-sea samples and used for PCR-amplification of 16S rRNA, FuBisCO and DSR genes. First, 16S rDNA from the deep-sea methane-rich seep sediment showed a diversified bacterial flora including sulfur-oxidizing bacteria (thiotrophs) and methane-oxidizing bacteria (methanotrophs). The occurrence of these thio-autotrophic and methanotrophic bacteria confirmed the idea that dense biological communities at methane-rich seeps are supported by microbial thiotrophic and methanotrophic production.Various types of RuBisCO genes were recovered from different deep … More -sea samples and analyzed ohy-ogenetically. The RuBisCO-based phylogenetic tree showed different cluster patterns from those of the 16S rDNA-based tree, which was ascribed to horizontal transfer of RuBisCO genes. Anaerobic RuBisCO genes were shown to distribute widely among the deep-sea samples, and their importance in the deep-sea autotrophic production was suggested.The genes of the DSR enzyme playing a major role in sulfate reduction were recovered from a deep-sea methane-rich seep. Phylogenetic analysis of the seep DSR genes showed the previously unknown DSR clusters presumably belonging to Archaea and Bacteria. Diversity of the DSR genes was greater than that of sulfate-reducing bacteria detected by the 16S rDNA-based analysis.Similar analyses were conducted with the samples collected from deep subsurface, and occurrence of diverse chemoautotrophs and anaerobes was demonstrated. Additionally, certain subsurface bacterial strains were isolated and cultured successfully. Taxonomic, phylogenetic and physiological characteristics are being studied. Less