Original paper

Quantitative detection of carboxydotrophic bacteria Carboxydothermus in a hot aquatic environment

Yoneda, Yasuko; Yoshida, Takashi; Daifuku, Takashi; Kitamura, Takayuki; Inoue, Takahiro; Kano, Sanae; Sako, Yoshihiko


CO-oxidizing bacteria, termed carboxydotrophs, have been assumed to play an important role in microbial environment as “CO-scavengers“. However, little is known about their ecology, especially in hydrothermal environments. In this study we focused on the members of the genus Carboxydothermus, the most studied thermophilic carboxydotrophs found in hot springs, which harbor unique sets of CO metabolisms. Carbon monoxide dehydrogenases (CODHs) are key enzymes of CO oxidation among these bacteria. We designed a real-time PCR primer set to amplify a conserved region of the gene encoding the CODH-II (cooS-II), and quantified Carboxydothermus in environmental samples. Real-time PCR primers developed in this study specifically amplified cooS-II partial sequences of 165-bp in length. The highest copy number of cooS-II obtained was 9.45 × 105 copies/ g sediment from a hot spring, equivalent to 10 % of Bacterial 16 S rRNA gene copies, while some samples were under detection level (< 1.0 × 102 copies). Apparently, the distribution of cooS-II was related to environmental temperature and microbial populations.


carboxydothermuscarboxydotrophthermophilecarbon monoxidereal-time pcrquantitative detectionhot spring