Physiological and genetic characterization of uncultured methanogenic archaea via an ultra-high sensitive fluorescence in situ hybridization technique

2015 Fiscal Year Final Research Report

• Project/Area Number: 25650138
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Biodiversity/Systematics
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: IMACHI Hiroyuki 国立研究開発法人海洋研究開発機構, 深海・地殻内生物圏研究分野, 主任研究員 (20361933)
• Co-Investigator(Renkei-kenkyūsha): KUBOTA Kengo 東北大学, 工学研究科, 准教授 (80455807)
• Research Collaborator: SAITO Yayoi
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: FISH法 / メタン菌 / mcrA遺伝子 / 生態

Outline of Final Research Achievements

The investigation of uncultured methanogens is a significant challenge in comprehensive understanding global carbon cycle. In this study, we aimed to gain physiological and genetic information of taxonomically new methanogens by obtaining genomic sequences and isolate. For this purpose, we first performed mcrA and 16S rRNA gene-based clone analyses on methanogenic sludges to explore taxonomically novel methanogens. Through the analyses, we found a novel methanogen group, which may represent the eighth order of methanogen. To obtain genetic information of the methanogen, we tried to do specific sorting of the methanogen cells using a combination of an ultra-high sensitive fluorescence in situ hybridization (FISH) technique (i.e., two-pass tyramide signal amplification FISH with polynucleotide probes) and fluorescence-activated cell sorting. However, unfortunately, the targeted methanogen cells could not be detected by the FISH technique even after several cell wall treatments.

Free Research Field

環境微生物学