Nakagawa Satoshi, Takaki Yoshihiro, Shimamura Shigeru, Reysenbach Anna-Louise, Takai Ken, Horikoshi Koki
Subground Animalcule Retrieval Program and Extremophiles Research Program, Extremobiosphere Research Center, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
Proc Natl Acad Sci U S A. 2007 Jul 17;104(29):12146-50. doi: 10.1073/pnas.0700687104. Epub 2007 Jul 5.
Deep-sea vents are the light-independent, highly productive ecosystems driven primarily by chemolithoautotrophic microorganisms, in particular by epsilon-Proteobacteria phylogenetically related to important pathogens. We analyzed genomes of two deep-sea vent epsilon-Proteobacteria strains, Sulfurovum sp. NBC37-1 and Nitratiruptor sp. SB155-2, which provide insights not only into their unusual niche on the seafloor, but also into the origins of virulence in their pathogenic relatives, Helicobacter and Campylobacter species. The deep-sea vent epsilon-proteobacterial genomes encode for multiple systems for respiration, sensing and responding to environment, and detoxifying heavy metals, reflecting their adaptation to the deep-sea vent environment. Although they are nonpathogenic, both deep-sea vent epsilon-Proteobacteria share many virulence genes with pathogenic epsilon-Proteobacteria, including genes for virulence factor MviN, hemolysin, invasion antigen CiaB, and the N-linked glycosylation gene cluster. In addition, some virulence determinants (such as the H(2)-uptake hydrogenase) and genomic plasticity of the pathogenic descendants appear to have roots in deep-sea vent epsilon-Proteobacteria. These provide ecological advantages for hydrothermal vent epsilon-Proteobacteria who thrive in their deep-sea habitat and are essential for both the efficient colonization and persistent infections of their pathogenic relatives. Our comparative genomic analysis suggests that there are previously unrecognized evolutionary links between important human/animal pathogens and their nonpathogenic, symbiotic, chemolithoautotrophic deep-sea relatives.
深海热液喷口是独立于光照、生产力极高的生态系统，主要由化能自养微生物驱动，特别是与重要病原体在系统发育上相关的ε-变形菌。我们分析了两种深海热液喷口ε-变形菌菌株——硫还原菌属NBC37-1和硝酸盐还原菌属SB155-2的基因组，这些基因组不仅能让我们深入了解它们在海底的特殊生态位，还能让我们了解其致病亲缘菌（幽门螺杆菌和弯曲杆菌属物种）毒力的起源。深海热液喷口ε-变形菌的基因组编码了多种呼吸、感知和响应环境以及解毒重金属的系统，这反映了它们对深海热液喷口环境的适应。尽管它们是非致病性的，但这两种深海热液喷口ε-变形菌都与致病性ε-变形菌共享许多毒力基因，包括毒力因子MviN、溶血素、侵袭抗原CiaB和N-连接糖基化基因簇。此外，一些毒力决定因素（如摄取氢气的氢化酶）和致病后代的基因组可塑性似乎起源于深海热液喷口ε-变形菌。这些为在深海栖息地繁衍生息的热液喷口ε-变形菌提供了生态优势，对于其致病亲缘菌的有效定殖和持续感染至关重要。我们的比较基因组分析表明，重要的人类/动物病原体与其非致病、共生、化能自养的深海亲缘菌之间存在以前未被认识到的进化联系。
