| 研究実績の概要 |
1)I was invited to partcipate in IODP (International Ocean Discovery Project) Expedition 370 as an onboard microbiologist from September to November 2016. While onboard the Chikyu, I collected core samples from 200m-1000m below the sea floor (Nankai Trough, Japan) for analysis of subseafloor viruses. Because the sediment biomass was so low, I developed a new method for separating viruses from sediment with extremely low biomass by using density gradient centrifugation. With the new method, I achieved an improvement of virus recovery by up to 200 times compared to old methods.
2)I analyzed the genomes of 4 microorganisms isolated from deep subseafloor coalbed collected 2km below the seafloor (Shimokita, Japan). Two isolates, Tenericutes MZ-XQ and MO-XQ, contain virus genes, suggesting that there may be a current prophage infection or past viral infection. They include genes encoding virus coat proteins and virus tail shaft proteins among other virus-associated genes. Two other isolates related to Methanobacteria have CRISPR loci, indicating previous viral infection.
3)Viruses were identified from the deep coalbed bioreactor by TEM. TEM analysis of the viruses revealed novel viral morphologies. The viruses were then collected. DNA(2ng) was extracted from the viruses and prepared for sequencing.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The research plan is on schedule. Extraction of viruses and cells from subseafloor sediment was accomplished. The abundance of cells from subseafloor sediment from the the Nankai Trough is low, therefore other subseafloor sites will be attempted as well. Viral DNA was successfully extracted from a subseafloor coal bed samples which were incubated inside a bioreactor. The DNA is ready for the next part of the project which will begin in the next fiscal year. In addition, a new virus extraction method was produced as a result of working on this research plan.
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| 今後の研究の推進方策 |
In summary, I made significant progress with my stated goals in the investigation of subseafloor viruses. In the next year, I will publish my new virus separation method, finish enumerating viruses from subseafloor samples, analyze the DNA I extracted from the subseafloor coalbed bioreactor, and determine if the prophage in a certain isolate can be isolated.
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