Japan Geoscience Union Meeting 2016

Presentation information


Symbol B (Biogeosciences) » B-CG Complex & General

[B-CG09] Interrelation between Life, Water, Mineral, and Atmosphere

Mon. May 23, 2016 1:45 PM - 3:00 PM A02 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Kentaro Nakamura(Department of Systems Innovation, School of Engineering, University of Tokyo), Tsubasa Otake(Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University), Yohey Suzuki(Graduate School of Science, The University of Tokyo), Ken Takai(Extremobiosphere Research Center, Japan Agency for Marine-Earth Science & Technology), Yuichiro Ueno(Department of Earth and Planetary Sciences, Tokyo Institute of Technology), Takeshi Naganuma(Graduate School of Biosphere Science), Takeshi Kakegawa(Graduate School of Science, Tohoku University), Tadashi Yokoyama(Department of Earth and Space Science, Graduate School of Science, Osaka University), Fumito Shiraishi(Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University), Chair:Fumito Shiraishi(Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University)

1:45 PM - 2:00 PM

[BCG09-01] Nano-sized biogenic iron oxides produced by neutrophilic Fe-oxidizing bacteria and its implications for biogeochemical cycling

★Invited papers

*Shingo Kato1 (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:Fe-oxidizing bacteria, Nano-sized iron oxides, Biogeochemical cycling

Neutrophilic microaerophilic Fe-oxidizing bacteria (NMFeOB) are thought to play a significant role in global biogeochemical cycling of Fe and associated elements. They are commonly found at redox boundaries in both of freshwater and marine iron-rich environments, and produce extracellular iron biominerals that interact with various elements. However, ecophysiology of NMFeOB is still poorly understood due to the difficulty of cultivation. Recently, Ferriphaselus amnicola strain OYT1 and Ferriphaselus sp. strain R-1, which produce a unique twisted-ribbon-like extracellular iron biomineral structure called a stalk, have been reported (Krepski et al., 2012; Kato et al., 2014). The present study demonstrates the strains OYT1 and R-1 also produce extracellular nano-sized biogenic iron oxides (nanoBIOS), which are morphologically distinct from stalks. Energy dispersive X-ray spectroscopy indicates that the nanoBIOS contain P, as well as the stalks. Given the chemical and morphological characteristics, nanoBIOS may contribute to P, Fe and other metal transport in the environment as a vector. Furthermore, the first genome sequencing of stalk-forming NMFeOB was performed in the present study. Comparative genomics propose potential genes involved in the formation of stalks and nanoBIOS, which are similar to genes involved in extracellular polysaccharide production, and potential genes in iron oxidation, which have been previously suggested as key iron oxidation genes in other NMFeOB. These genes can be used as marker genes for detection of NMFeOB producing iron biominerals. Overall, the detailed microscopy and first genomic analysis of the freshwater stalk-forming NMFeOB provide novel insight into the ecophysiology and biomineralization of enigmatic NMFeOB.