岡山大学農学部Acta Medica Okayama2186-77551092020酸性鉱山廃水の 効果的な生物的処理プロセスの開発2936ENKazuoKamimuraGraduate School of Environmental and Life Science, Okayama UniversityTadayoshiKanaoGraduate School of Environmental and Life Science, Okayama University Acid mine drainage (AMD) is acidic and generally enriched with iron, aluminum, sulfate and heavy metals, such as lead and cadmium. AMD is a growing problem of emerging concern that cause detrimental effects to the environment and living organisms. Yanahara mine in Misaki Town, Okayama, Japan, had mainly produced pyrite for sulfuric acid manufacture. Although it was closed in 1991, AMD is being generated from the mine now. A passive treatment based on the biological oxidation of ferrous iron is a promising strategy for AMD remediation. AMD from Yanahara mine is treated in a plant using iron-oxidizing bacteria, Acidithiobacillus ferrooxidans and Ferrovum spp. The AMD generation continues for several centuries with dramatic consequences on the receiving environments. Therefore, the development of sustainable and cost effective treatment process is required. A development of the effective biological treatment process with an iron oxidation reactor operated at pH 3.5 is described in this report. Economic aspects are also discussed.No potential conflict of interest relevant to this article was reported.岡山大学農学部Acta Medica Okayama2186-77551042015Characterization of a putative chromosome segregation and condensation protein (ScpB) in an acidophilic iron‒oxidizing bacterium Acidithiobacillus ferrooxidans512ENKazuoKamimuraNozomuNagataMeiKikumotoSultanaSharminSatoshiWakaiTadayoshiKanao Acidithiobacillus ferrooxidans is one of the most widely used microorganisms in bioleaching operations to recover copper from low-grade copper sulfide. This bacterium uses ferrous iron and reduced inorganic sulfur compounds (RISCs) as energy sources. Transcriptions of genes thought to be involved in the oxidation of RISCs have been known to be highly activated in A. ferrooxidans cells grown on RISCs, while transcriptions of genes involved in the iron oxidation were repressed in the cells grown on
RISCs. A gene encoding a putative chromosome segregation and condensation protein (ScpB) with a
helix-turn-helix motif was found in the upstream region of sulfide : quinone oxidoreductase gene, whose expression was up-regulated in cells grown in sulfur and tetrathionate. A semi-quantitative PCR analysis using cDNA prepared from iron-, sulfur-, or tetrathionate-grown cells revealed that the transcription of scpB was up-regulated in cells grown on sulfur or tetrathionate as the energy source. Electrophoretic mobility shift assays were employed to examine whether the ScpB functions as a transcription factor. The result indicated that the recombinant His-tagged ScpB protein was able to nonspecifically bind in
vitro to DNA. This is the first report on a direct association of ScpB with DNA.No potential conflict of interest relevant to this article was reported.Springer JapanActa Medica Okayama1431-06511532011Characterization of an OmpA-like outer membrane protein of the acidophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans403410ENMohammed AbulManchurMeiKikumotoTadayoshiKanaoJunTakadaKazuoKamimuraAn OmpA family protein (FopA) previously reported as one of the major outer membrane proteins of an acidophilic iron-oxidizing bacterium Acidithiobacillus ferrooxidans was characterized with emphasis on the modification by heat and the interaction with peptidoglycan. A 30-kDa band corresponding to the FopA protein was detected in outer membrane proteins extracted at 75A degrees C or heated to 100A degrees C for 10 min prior to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). However, the band was not detected in outer membrane proteins extracted at a parts per thousand currency sign40A degrees C and without boiling prior to electrophoresis. By Western blot analysis using the polyclonal antibody against the recombinant FopA, FopA was detected as bands with apparent molecular masses of 30 and 90 kDa, suggesting that FopA existed as an oligomeric form in the outer membrane of A. ferrooxidans. Although the fopA gene with a sequence encoding the signal peptide was successfully expressed in the outer membrane of Escherichia coli, the recombinant FopA existed as a monomer in the outer membrane of E. coli. FopA was detected in peptidoglycan-associated proteins from A. ferrooxidans. The recombinant FopA also showed the peptidoglycan-binding activity.No potential conflict of interest relevant to this article was reported.岡山大学農学部Acta Medica Okayama0474-02548711998Activities of Iron Oxidase and Hydrogen Sulfide: ferric Ion Oxidoreductase of Thiobacillus ferrooxidans isolated from natural environments7783ENTsuyoshiSugioIsaoFujiwaraMariHanaseKazuoKamimuraIt has been reported that both iron oxidase and hydrogen sulfide: ferric ion oxidoreductase (SFORase) were involved in bacterial leaching of metal ions from sulfide ores, and the amount of Cu2+ solubilized from copper ore by iron-oxidizing bacterium differed from strain. The activities of iron oxidase SFORase of iron-oxidizing bacteria isolated from the natural environments were determined. Iron-oxidizing activity and SFORase activity of 200 strains ranged from 1.20-1.65γmol/mg/min and from 0.11-2.80 γmol/mg/min, respectively. The findings that a remarkable difference was observed in the levels of SFORase activity, but not in iron-oxidizing activity, suggest that SFORase, but not iron oxidase, is the enzyme that determines the bacterial leaching activity of this bacterium.No potential conflict of interest relevant to this article was reported.岡山大学農学部Acta Medica Okayama0474-02548811999深海環境への微生物の適応機構に関する研究121130ENKazuoKamimuraThe world's oceans cover 70% of the eath's surface,with about 3,800m of average depth.Altough the deep-sea environment with its high pressure and low temperatures is too extreme for most terrestrial and marine surface microorganisms,many barotolerant and barophilic bacteria have been found inhabiting the deep-sea.It is exyremely important for barophilic or barotolerand deep-sea bacteria to maintain the physiological functions of cytoplasmic membrane,which serves many vital functions.The fluidity of this cytoplasimic membrane composed of phospholipids and poteins is essential for the physiological functions of cells.As higher hydorstatic pressure raise the melting point of lipids and cause phase transition
of lipid under pressurs of up to 100MPa,barotolerant and barophilic bacrteria under high hydostatic pressure appear to regulate the composition of their membrane phospholipids. Therfore the characrization of cytoplasmic membrane under high pressure is indispensable to clarify the mecanisms of bacteria adaptation to the deep-sea enviroment.The effects of pressure and temperature acid compositon of barotolerant deep-sea bacteria were investigated.Deep-sea bacteria maintained their membrane fluidity by increasing the content of unique fatty acid in phospholipids under high hydrostatic pressure.Gene expression seems to be necessary for the synthesis of unique fatty under high hydrostatic pressure.No potential conflict of interest relevant to this article was reported.岡山大学農学部Acta Medica Okayama0474-02549112002Mechanism of Oxidation of Reduce Sulfur Compounds by Sulfur-Grown Acidithiobacillus Caldus Strain GO-12329ENKazuoKamimuraRyokoSawadaTsuyoshiSugioThe oxidation of reduced sulfur compounds was studied by using resting cells of sulfur-grown Acidithiobacillus caldus strain GO-1. The optimum pHs for the oxidation of thiosulfate, tetrathionate, sulfur, sulfite and sulfide were 2, 3, 3-6, 7 and 7, respectively. The highest oxidation rate was observed with sulfite. The oxidation rates of the reduced sulfur compounds were measured in the absence or presence of inhibitors and uncouplers. 2, 4-dinitrophenol (DNP) and carbonyl cyanide-m-chlorophenylhydrazone (CCCP) strongly inhibited the oxidations of sulfur and sulfite. N-Ethylmaleimide (NEM) strongly inhibited the oxidation of tetrathionate and sulfur. 2-heptyl-4-hydroxy-quinoline-N-oxide(HQNO) inhibited the oxidation of sulfur and sulfite. The results suggested that tetrathionate was oxidized in the periplasmic space, and sulfur and sulfite were oxidized in the cytoplasm. Pyridine ferrohemochromes prepared from the membrane of strain GO-1 cell revealed the involvement of cytochromes b and c. Ubiquinol oxidase activity was detected in strain GO-1 cell, but cytochrome c oxidase measured by using mammalian cytochrome c as an electron donor was not detected in the cell. On the basis of the results a model for the metabolism of the reduced sulfur compounds by At. caldus strain GO-1 was proposed.No potential conflict of interest relevant to this article was reported.岡山大学農学部Acta Medica Okayama0474-02549512006Discrimination among the Three Acidithiobacillus Species, A. ferrooxidans, A. thiooxidans and A. caldus, Based on Restriction Fragment Length Polymorphism Analysis of the 16S-23S rDNA Intergenic Spacer Region711ENSatoshiWakaiKentaroYamamotoTadayoshiKanaoTsuyoshiSugioKazuoKamimuraThe PCR-amplified 16S-23S rDNA intergenic spacer regions (ISRs) of Acidithiobacillus ferrooxidans, A. thiooxidans, and A. caldus strains were scquenced and evaluated for differentiation and identification of these bacteria. The total length of the 16S-23S ISRs of A. ferrooxidans and A. thiooxidans strains and A.caldus GO-1 were 441, 456, nd 379bp, respectively. Two genes. encoding tRNA and tRNA, and the box A-like sequences were highly conserved in the ISRs of all Acidithiobacillus species. The restriction fragment length polymorphism (RFLP) profiles of the PCR-amplified 16S-23S rDNA ISRs digested by HaeIII and AluI could clearly discriminate A. ferrooxidans from A. thiooxidans and A. caldus. The results indicated that RFLP analysis of the 16S-23S ISRs is an easy and rapid method for discrimination and identification of Acidithiobacillus species.No potential conflict of interest relevant to this article was reported.