Abstract
The oxidation of reduced inorganic sulfur compounds was studied by using resting cells of the moderate thermophile Thiobacillus caldus strain KU. The oxygen consumption rate and total oxygen consumed were determined for the reduced sulfur compounds thiosulfate, tetrathionate, sulfur, sulfide, and sulfite in the absence and in the presence of inhibitors and uncouplers. The uncouplers 2,4-dinitrophenol and carbonyl cyanide m-chlorophenyl-hydrazone had no affect on the oxidation of thiosulfate, suggesting that thiosulfate is metabolized periplasmically. In contrast, the uncouplers completely inhibited the oxidation of tetrathionate, sulfide, sulfur, and sulfite, indicating that these compounds are metabolized in the cytoplasm of T. caldus KU. N-Ethylmaleimide inhibited the oxidation of tetrathionate and thiosulfate at the stage of elemental sulfur, while 2-heptyl-4-hydroxyquinoline-N-oxide stopped the oxidation of thiosulfate, tetrathionate, and elemental sulfur at the stage of sulfite. The following intermediates in the oxidation of the sulfur compounds were found by using uncouplers and inhibitors: thiosulfate was oxidized to tetrathionate, elemental sulfur was formed during the oxidation of tetrathionate and sulfide, and sulfite was found as an intermediate of tetrathionate and sulfur metabolism. On the basis of these data we propose a model for the metabolism of the reduced inorganic sulfur compounds by T. caldus KU.
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Selected References
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- Amaro A. M., Hallberg K. B., Lindström E. B., Jerez C. A. An immunological assay for detection and enumeration of thermophilic biomining microorganisms. Appl Environ Microbiol. 1994 Sep;60(9):3470–3473. doi: 10.1128/aem.60.9.3470-3473.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goebel B. M., Stackebrandt E. Cultural and phylogenetic analysis of mixed microbial populations found in natural and commercial bioleaching environments. Appl Environ Microbiol. 1994 May;60(5):1614–1621. doi: 10.1128/aem.60.5.1614-1621.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hallberg K. B., Lindström E. B. Characterization of Thiobacillus caldus sp. nov., a moderately thermophilic acidophile. Microbiology. 1994 Dec;140(Pt 12):3451–3456. doi: 10.1099/13500872-140-12-3451. [DOI] [PubMed] [Google Scholar]
- Hazeu W., Bijleveld W., Grotenhuis J. T., Kakes E., Kuenen J. G. Kinetics and energetics of reduced sulfur oxidation by chemostat cultures of Thiobacillus ferrooxidans. Antonie Van Leeuwenhoek. 1986;52(6):507–518. doi: 10.1007/BF00423411. [DOI] [PubMed] [Google Scholar]
- Matin A., Wilson B., Zychlinsky E., Matin M. Proton motive force and the physiological basis of delta pH maintenance in thiobacillus acidophilus. J Bacteriol. 1982 May;150(2):582–591. doi: 10.1128/jb.150.2.582-591.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SORBO B. A colorimetric method for the determination of thiosulfate. Biochim Biophys Acta. 1957 Feb;23(2):412–416. doi: 10.1016/0006-3002(57)90346-3. [DOI] [PubMed] [Google Scholar]