Studies on the biodiversity of methanogens from hydrothermal vent chimney
深海热液喷口金属硫化物中甲烷菌的多样性研究

The chimney sulfides (named 4136-2 and 4148-B1) obtained from Juan de Fuca Ridge were used as samples, aiming at mcrA gene amplification, clone library construction and phylogenetic tree analysis. The results showed that there were only CH4 production microbes but no CH4 oxidation microbes in the samples and the species in the two sulfides were different. The methanogen from 4136-2 sulfide rock were linked to a high temperature environment. These methanogen belong to Methanocaldococcus and Methanopyrus kandleri. The similarities of protein sequences between 4136-2 clones and isolated Methanocaldococcus and Methanopyrus kandleri strains were from 89% to 97%, and The similarities of mucleotide sequences between 4136-2 clones and isolated Methanocaldococcus and Methanopyrus kandleri strains were from 92% to 100%. The mcrA sequences from 4148-B1 sulfide rock had low identities with sequences deposited in GenBank. The similarities of mucleotide sequences identities of 4148-B1 clones and published mcrA sequences were form 69% to 72%, and the similarities of protein sequences were form 43% to 37%. This also linked to its super high temperature environment and may suggest there were un-discovered methanogen living in the vent.