A Study on the Marine Prokaryotic Diversity and Antibiotic Resistome using High-Throughput Sequencing and Functional Metagenomic Analysis ; 대량 염기서열 분석법과 기능적 메타지놈 분석법을 이용한 해양 원핵생물의 다양성과 항생제 내성군 연구

학위논문 (박사)-- 서울대학교 대학원 : 지구환경과학부, 2016. 8. 조병철. ; Prokaryotes (Bacteria and Archaea) play a significant role in global biogeochemical flux of biologically important elements in marine ecosystems. It has been firmly established that prokaryotes are major primary producers and heterotrophic consumers. Despite prokaryotes have significant roles in the biogeochemical flux in marine environmets, it has been estimated that more than 99% of the bacteria are non-culturable, leading to limited information of prokaryotic diversity because of an inability to mimic proper environmental niches. The relation between prokaryotic communities and their roles in the biogeochemical cycle is a topic of central research in environmental microbiology. Knowledge of the prokaryotic community compositions has rapidly increased due to development of molecular techniques based on amplification of the 16S rRNA gene and sequencing. This thesis includes studies on i) seasonal and spatial distribution of diversity of marine prokaryotes in the East Sea using pyrosequencing, ii) marine bacteria can be dispersed in the atmospheric environments, and iii) diversity of antibiotic resistance genes in the water column of the East Sea using the functional metagenomics approach. i) To understand in-depth prokaryotic diversity using high-throughput sequencing technique, we applied a pyrosequencing approach to study spatial and seasonal distribution of prokaryotes in the East Sea during 2011-2014. This study demonstrates that bacterial and archaeal communities varied along horizontal scale from coastal to offshore as well as vertical scale along depth, and furthermore their distribution patterns were different between seasons. Bacteroidetes, Alpha- and Gamma-proteobacteria dominated from epipelagic to mesopelagic zones in the East Sea. However, the discrepancy must be resulted from the low coverage of used primer for a major Alpha-proteobacteria group (SAR11). Thaumarchaeota and Euryarchaeota were dominant archaea in the epipelagic zone (0-100 m). ...