碩士 / 國立中興大學 / 生命科學系所 / 106 / Viruses infect all Three Domains of lifes, however the knowledge of archaeal viruses is limited. Lately, the diverse virus morphology and the independent virus development outside the extreme thermophilic/acidophilic archaeal host attracted the attention on archaeal virus investigations. Currently, over 100 archaeal viruses have been discovered, most related to thermophilic Crenarchaea and extreme halophilic Euryarchaea. However, almost none methanoarchaeal virus was reported for the past two decades. From the core sediment on the top of gas hydrate habitat in the deformation front site offshore south-western Taiwan, Methanoculleus taiwanensis CYW4T was enriched, isolated and characterized. Cell lysis was observed at stationary phase and a lytic virus which caused the lysis of strain CYW4T was observed under TEM. The spherical shape virion, about 100 nm, with the icosahedral capsids and envelope was named as VMta (Virus of Methanoculleus taiwanensis). VMta is a dsDNA virus which contained 70,262 bp with a mol% G+C content of 54.5 and 101 putative open reading frames (ORFs). Base on the VMta genome information and analysis through BLASTX and HHpred, it was suggested that the VMta may injected the DNA into the host by the puncture protein and replicated their genomes through the rolling-circle replication (RCR) mechanism. The viral DNAs were packed into the empty capsid by the terminase enzymes and virons left host cell with the endolysin disruption.
Methanoculleus sp. CWC-02 were enriched from the marine sediment of the Good weather ridge. Phylogenetic analysis revealed that strain CWC-02 was closely related to Methanoculleus marisnigri JR1T (98.4% 16S rRNA gene sequence similarity). Genome relatedness between strain CWC-02 and Methanoculleus marisnigri JR1T was computed using both average nucleotide identity (ANI) and genome-to-genome distance calculator (GGDC) with values of 86.81% and 32.50%, respectively. According to genomic data, it is patent the strain CWC-02 may the novel new species. Strain CWC-02 used H2 plus CO2, formate, 2-propanol and 2-butanol as catabolic substrates. The optimum growth temperature was 37℃. The stationary phase growth of strain CWC-02 cells also observed virus-like particles under TEM. The occurrence of methanoarchaeal viruses at the methane (gas) hydrate ecosystems indicated that viruses may play a role in acceleration of the carbon and nutritional cycling.
| Identifer | oai:union.ndltd.org:TW/106NCHU5105018 |
| Date | January 2018 |
| Creators | Wen-Hsin Wei, 魏文心 |
| Contributors | Mei-Chin Lai, 賴美津 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 111 |
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