日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 B (地球生命科学) » B-CG 地球生命科学複合領域・一般

[B-CG06] 地球惑星科学 生命圏フロンティアセッション

2019年5月28日(火) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:高野 淑識(海洋研究開発機構)、鈴木 庸平(東京大学大学院理学系研究科)、加藤 真悟(国立研究開発法人理化学研究所)、福士 圭介(金沢大学環日本海域環境研究センター)

[BCG06-P07] Carbon signatures in amino acids during deep-sea anoxic methanotrophy

*高野 淑識1 (1.海洋研究開発機構)

キーワード:Carbon signatures in ANMEs、Organic molecules、Anoxic methanotrophy

Microorganisms play a central role in both methane production and consumption in the global carbon cycle. Oceanic methane from global deep-sea sediment is largely consumed through microbially mediated sulfate-coupled oxidation, resulting in 13C-depleted cell biomass of anaerobic methanotrophic archaea (ANME). The general ecological importance of subseafloor ANME has been well recognized in the last two decades. However, the crucial biochemical pathways for the overall anaerobic oxidation of methane (AOM) still remain enigmatic. In the present study, methanotrophic pathways were analyzed to trace 13C-depleted amino acid biosynthesis in two clades of ANME (ANME-1 and ANME-2) from the Black Sea. Compound-specific analysis of ANME-dominated microbial mats showed a significant 13C-depletion trend in association with increasing carbon numbers in protein-derived amino acid families within the pyruvate family in the order of alanine, valine, isoleucine and leucine down to -114‰. This result indicates a stepwise elongation of 13C-depleted carbon during amino acid biosynthesis. The overall results suggest that intracellular protein amino acids and the most 13C-depleted signature of leucine, which has a specific branched-chain structure, are potentially propagated as isoprenoid precursor molecules into archaeal biosynthesis, resulting in the extremely 13C- and 14C-depleted nature of ANME cells in the deep microbial oasis.

References:
Takano, Y., Chikaraishi, Y., Imachi, H., Miyairi, Y., Ogawa, N.O., Kaneko, M., Yokoyama, Y., Kruger, M. and Ohkouchi, N. (2018) Insight into anaerobic methanotrophy from 13C/12C- amino acids and 14C/12C-ANME cells in seafloor microbial ecology. Scientific Reports, 8:14070, doi: 10.1038/s41598-018-31004-5.

Supplementary Information:
https://www.nature.com/articles/s41598-018-31004-5#article-info

Acknowledgments:
We thank Dr. R. Seifert and Prof. Dr. W. Michaelis (Univ. Hamburg) and the shipboard party of the R/V Meteor cruise (M72/1: Geochemical cycling and microbial life at active gas seeps). We also thank Y. Saito, Y. Sasaki (JAMSTEC) for technical support and Dr. Y. Takaki (JAMSTEC) for the discussion of genomic sequence. The study was supported in part by the Japan Society for the Promotion of Science (JSPS) and the Submarine Resources Research Project in JAMSTEC.