title: Dissimilatory iodate reduction by marine Pseudomonas sp. strain SCT.
abstract: Bacterial iodate (IO(3)(-)) reduction is poorly understood largely due to the limited number of available isolates as well as the paucity of information about key enzymes involved in the reaction. In this study, an iodate-reducing bacterium, designated strain SCT, was newly isolated from marine sediment slurry. SCT is phylogenetically closely related to the denitrifying bacterium Pseudomonas stutzeri and reduced 200 microM iodate to iodide (I(-)) within 12 h in an anaerobic culture containing 10 mM nitrate. The strain did not reduce iodate under the aerobic conditions. An anaerobic washed cell suspension of SCT reduced iodate when the cells were pregrown anaerobically with 10 mM nitrate and 200 microM iodate. However, cells pregrown without iodate did not reduce it. The cells in the former category showed methyl viologen-dependent iodate reductase activity (0.31 U mg(-1)), which was located predominantly in the periplasmic space. Furthermore, SCT was capable of anaerobic growth with 3 mM iodate as the sole electron acceptor, and the cells showed enhanced activity with respect to iodate reductase (2.46 U mg(-1)). These results suggest that SCT is a dissimilatory iodate-reducing bacterium and that its iodate reductase is induced by iodate under anaerobic growth conditions.
authors.affiliation: Department of Bioresources Chemistry, Chiba University, 648 Matsudo, Matsudo-shi, Chiba 271-8510, Japan. amachi@faculty.chiba-u.jp
authors.forename: Seigo
authors.initials: S
authors.lastname: Amachi
authors.forename: Nahito
authors.initials: N
authors.lastname: Kawaguchi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Muramatsu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: Yuko
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shinoyama
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujii
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D007452:Iodates / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism*; D010084:Oxidation-Reduction; D011549:Pseudomonas / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D007452:Iodates; D009566:Nitrates