TY - JOUR
T1 - Growth Stimulation of Iodide-Oxidizing α-Proteobacteria in Iodide-Rich Environments
AU - Arakawa, Yumi
AU - Akiyama, Yukako
AU - Furukawa, Hideharu
AU - Suda, Wataru
AU - Amachi, Seigo
N1 - Funding Information:
This work was partially supported by Grant-in-Aid for Young Scientists (B) No. 20780049 from the Japan Society for the Promotion of Science and a grant from Showa Shell Sekiyu Foundation to S. A. We thank H. Yamaguchi (Kanto Natural Gas Development Co.) for providing information regarding the DPD method, Y. Sekiguchi (National Institute of Advanced Industrial Science and Technology) for designing the IOB-specific primers, and T. Fujii (Chiba University) and H. Shinoyama (Meisei University) for encouragement and helpful discussion.
PY - 2012/4
Y1 - 2012/4
N2 - α-Proteobacteria that can oxidize iodide (I -) to molecular iodine (I 2) have only been isolated from iodide-rich natural and artificial environments, i. e., natural gas brine waters and seawaters supplemented with iodide, respectively. To understand the growth characteristics of such iodide-oxidizing bacteria (IOB) under iodide-rich environments, microcosms comprising natural seawater and 1 mM iodide were prepared, and the succession of microbial communities was monitored by culture-independent techniques. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequence analysis showed that bacteria closely related with known IOB were predominant in the microcosms after several weeks of incubation. Quantitative PCR analysis targeting specific 16S rRNA gene regions of IOB showed that the relative abundance of IOB in the microcosms was 6-76% of the total bacterial population, whereas that in natural seawater was less than 1%. When 10 3 cells mL -1 of IOB were inoculated into natural seawater supplemented with 0. 1-1 mM iodide, significant growth (cell densities, 10 5-10 6 cells mL -1) and I 2 production (6-32 μM) were observed. Interestingly, similar growth stimulation occurred when 12-44 μM of I 2 was added to seawater, instead of iodide. IOB were found to be more I 2 tolerant than the other heterotrophic bacteria in seawater. These results suggest that I 2 plays a key role in the growth stimulation of IOB in seawater. IOB could potentially attack other bacteria with I 2 to occupy their ecological niche in iodide-rich environments.
AB - α-Proteobacteria that can oxidize iodide (I -) to molecular iodine (I 2) have only been isolated from iodide-rich natural and artificial environments, i. e., natural gas brine waters and seawaters supplemented with iodide, respectively. To understand the growth characteristics of such iodide-oxidizing bacteria (IOB) under iodide-rich environments, microcosms comprising natural seawater and 1 mM iodide were prepared, and the succession of microbial communities was monitored by culture-independent techniques. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequence analysis showed that bacteria closely related with known IOB were predominant in the microcosms after several weeks of incubation. Quantitative PCR analysis targeting specific 16S rRNA gene regions of IOB showed that the relative abundance of IOB in the microcosms was 6-76% of the total bacterial population, whereas that in natural seawater was less than 1%. When 10 3 cells mL -1 of IOB were inoculated into natural seawater supplemented with 0. 1-1 mM iodide, significant growth (cell densities, 10 5-10 6 cells mL -1) and I 2 production (6-32 μM) were observed. Interestingly, similar growth stimulation occurred when 12-44 μM of I 2 was added to seawater, instead of iodide. IOB were found to be more I 2 tolerant than the other heterotrophic bacteria in seawater. These results suggest that I 2 plays a key role in the growth stimulation of IOB in seawater. IOB could potentially attack other bacteria with I 2 to occupy their ecological niche in iodide-rich environments.
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U2 - 10.1007/s00248-011-9986-5
DO - 10.1007/s00248-011-9986-5
M3 - Article
C2 - 22138964
AN - SCOPUS:84858003750
SN - 0095-3628
VL - 63
SP - 522
EP - 531
JO - Microbial Ecology
JF - Microbial Ecology
IS - 3
ER -