生物谷報(bào)道：日本科學(xué)家發(fā)現(xiàn),，存活在人體內(nèi)臟中使人生病的某些致病細(xì)菌可能是由生活在海洋深處,、能經(jīng)受極限環(huán)境考驗(yàn)的它們的始祖進(jìn)化而來。
日本科學(xué)家在最新一期美國《國家科學(xué)院學(xué)報(bào)》上發(fā)表文章說,，他們分析了兩種致病內(nèi)臟細(xì)菌的基因排序,，并將其與兩種類型非常接近、但生活在海底深處的無害細(xì)菌進(jìn)行比較,。
科學(xué)家們發(fā)現(xiàn),，內(nèi)臟細(xì)菌和海底的細(xì)菌有著許多相似的基因，這些基因使其能夠在極端環(huán)境下生長,。它們還具有極少量的ＤＮＡ修復(fù)基因,，允許出現(xiàn)頻繁的突變，并快速適應(yīng)不斷變化的環(huán)境以及共生宿主的免疫反應(yīng),。
科學(xué)家在文章中說,，這種特性使得內(nèi)臟細(xì)菌能夠“不斷傳染”。
科學(xué)家所選取的這兩種細(xì)菌分別是導(dǎo)致內(nèi)臟潰瘍的螺旋菌及造成出血性腹瀉的彎曲桿菌。
在深海中發(fā)現(xiàn)的是兩種變形細(xì)菌——Ｓｕｌｆｕｒｏｖｕｍ和Ｎｉｔｒａｔｉｒｕｐｔｏｒ,，它們生活在非常惡劣的環(huán)境中,，只有最強(qiáng)壯的微生物才能在那里存活下來。(新華網(wǎng))
原始出處:
Published online before print July 5, 2007, 10.1073/pnas.0700687104
PNAS | July 17, 2007 | vol. 104 | no. 29 | 12146-12150
Deep-sea vent -proteobacterial genomes provide insights into emergence of pathogens
Satoshi Nakagawa,, Yoshihiro Takaki, Shigeru Shimamura, Anna-Louise Reysenbach¶, Ken Takai, and Koki Horikoshi,
Subground Animalcule Retrieval (SUGAR) Program and Extremophiles Research Program, Extremobiosphere Research Center (XBR), Japan Agency for Marine–Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan; and ¶Department of Biology, Portland State University, Portland, OR 97201
Edited by Rita R. Colwell, University of Maryland, College Park, MD, and approved June 7, 2007 (received for review January 25, 2007)
Deep-sea vents are the light-independent, highly productive ecosystems driven primarily by chemolithoautotrophic microorganisms, in particular by -Proteobacteria phylogenetically related to important pathogens. We analyzed genomes of two deep-sea vent -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 -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 -Proteobacteria share many virulence genes with pathogenic -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 H2-uptake hydrogenase) and genomic plasticity of the pathogenic descendants appear to have roots in deep-sea vent -Proteobacteria. These provide ecological advantages for hydrothermal vent -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.
-Proteobacteria | comparative microbial genomics | deep-sea hydrothermal vent | pathogenesis | symbiosis
