Isolation and Characterization of Methanofollis Species from Potential Cold Seep Area-Four Way Closure Ridge Offshore SW Taiwan

• Main Authors: Nai-Hsuan Teng, 鄧乃瑄
• Other Authors: 賴美津
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/jw54qx

碩士 === 國立中興大學 === 生命科學系所 === 106 === Four Way Closure Ridge is an anticlinal ridge that represents an ideal trap for methane hydrate accumulations through the analyses of high-resolution bathymetry, deep-towed sidescan sonar imagery, high-resolution seismic profiling and towed video observations of the seafloor. Four Way Closure Ridge is one of the sites with intensive methane seepages to bring up a typical cold seep used methane as substrate chemosynthetic community and with highly dense mussel bed with shrimps, crabs and clams was found at this site. A mesophilic, hydrogenotrophic methanogen, strain FWC-SCC2, was isolated from deep-sea sediment obtained at the C5-6 station at Four Way Closure Ridge region by the R/V Ocean Researcher III during ORIII-1900 cruise in 2015. Phylogenetic analysis revealed that strain FWC-SCC2 was most closely related to Methanofollis tationis Chile 9T (98.2% 16S rRNA gene sequence similarity) and share 96-98 % 16S rRNA gene sequence similarity with other valid Methanofollis species. Genome relatedness between strain FWC-SCC2 and Methanofollis genus was computed using both average nucleotide identity (ANI) and genome-to-genome distance analysis (GGDA) with values of 78.2-79.8% and 17.8-23.8%, respectively. Based on the morphological, phenotypic and phylogenetic characteristics presented here, it is suggested that strain FWC-SCC2 represents a new species of genus Methanofollis. The cells were irregular cocci, non-motile with 0.8-1.2 μm in diameter. The Mr of surface-layer protein was 116.4 kDa. Strain FWC-SCC2 used H2/CO2 or formate as catabolic substrates. The growth conditions were at 20-40C, 0-0.85 M NaCl and pH 5.9-8.2. Comparative genomic analysis between strain FWC-SCC2 and other Methanofollis reveals strain FWC-SCC2 have 38 unique COGs, included ABC-type iron transport system FetAB, quinol monooxygenase YgiN, two type aerotolerant COGs and phage shock protein A that can maintain cell membrane integrity.