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At least 19 recordsLinked to original sources
PubMed1978

Sulfide oxidation by spheroplasts of Thiobacillus ferrooxidans.

Thiobacillus ferrooxidans is an acidophilic organism important to metal leaching of low-grade ores. The aforementioned importance is related to the ability of the bacterium to oxidize reduced iron and sulfur, principally found in nature as pyrite (FeS2). The present study dealt with sulfide oxidation at low pH values and the involvement of the cell envelope in the process of the inorganic oxidations. Sulfide oxidation was noted in spheroplasts of T. ferrooxidans prepared by enzymatic and chemical treatments and partially purified by differential centrifugation. No enzyme activities were noted in membrane fractions containing enrichments of lipopolysaccharide symbolic of outer membrane material or in membrane vesicles containing (or associated with) higher levels of proteins. Results to date indicate that in an acid milieu the envelope structure containing both the outer membrane and the intact inner cytoplasmic membrane is required for sulfide oxidation.

Cell Membrane↗
PubMed2026

Sulfide-oxidizing potential and hypersalinity tolerance strategies in salt-crust covered coastal microbial mats.

Hypersaline microbial mats are dense microbial ecosystems capable of performing nearly complete element cycling under harsh conditions including near-saturation salinity. Our previous study of salt-crust-covered microbial mats showed that oxygenic photosynthesis was inhibited at salt saturation, while phototrophic sulfide oxidation persisted despite well-known sulfide-oxidizing taxa being undetectable. In this study, we analyzed metagenome-assembled genomes (MAGs) from the same mats to identify sulfide-oxidizing taxa and adaptations enabling oxygenic phototrophs to survive salt saturation. We extended the dataset by including morphologically identical mats exposed to lower salinity regimes to identify metabolic capabilities specifically selected for by saturation-level salinity. The phototrophic sulfide oxidation capability was found in nearly all cyanobacterial MAGs, in some Chloroflexota, and in abundant Rhodovibrio populations previously not known to oxidize sulfide. Furthermore, we found clear indications of Haloarchaea-like potassium-based osmoregulation in Bradymonadaceae (Myxococcota) adding another taxon to the few known potassium-accumulating bacteria. Despite lower oxygen concentrations, salt-crust-covered mats showed smaller proportions of fermenters and higher proportions of aerobic microorganisms than lower-salinity mats. We compared the genetic signatures of hypersalinity and desiccation tolerance in cyanobacterial MAGs from this study to genomes from desiccation-prone environments such as desert soils and small freshwater streams. Genomes of hyperhalophilic cyanobacteria were characterized by lack of certain potassium transporters and catalase genes and presence of additional osmolyte transporter subunits and sulfide-oxidation genes. We hypothesize that during salt saturation the oxidative stress for mat dwelling cyanobacteria is lowered, while the ability to oxidize sulfide provides them with energy when oxygenic photosynthesis is inhibited.

Oxidation-Reduction↗
PubMed1978

Oxidation of gallium sulfides by Thiobacillus ferrooxidans.

The bacterial oxidation of naturally occurring gallium-bearing chalcopyrite concentrate and a pure synthetic gallium (III) sulfide has been investigated at pH 1.8 and 35 degree C, using an active culture of Thiobacillus ferrooxidans. This oxidation process may proceed by direct or by indirect bacterial action. The highest dissolved gallium and copper concentrations were about 2.2 and 40.2 g/l, respectively. The order of the specific rate of oxygen uptake by T. ferrooxidans in approximately CuFES2 greater than or equal to gallium-bearing CuFeS2 greater than FeS2 greater than Cu2S greater than Cu2S greater than Ga2S3.

Copper↗
PubMed1978

Hetacillin (R)- and (S)-sulfoxides. Synthesis and structure-activity relationships.

Hetacillin was oxidized with m-chloroperbenzoic acid to give the corresponding (R)- and (S)-sulfoxides. Ozonization of hetacillin not only oxidized the sulfide but caused unexpected oxidation of the imidazolidine ring to a 2H-imidazoline. The biological spectrum showed the (R)-sulfoxide to be appreciably more active than the (S)-sulfoxide.

Animals↗
PubMedDate not supplied

Oxisuran metabolism in pigs.

The fate of oxisuran in the pig was studied with 14C-labeled drug to quantify its biotransformation and disposition. Despite interanimal differences, it was clear that the compound absorbed rapidly and biotransformed extensively to metabolites which were excreted principally in urine rather than in feces. Direct attacks upon oxisuran involved reduction to diastereo-isomeric oxisuran alcohol sulfoxides and oxidation to oxisuran sulfone. Subsequently, the oxisuran alcohol sulfoxides were reduced to a sulfide and oxidized to a sulfone. Phase II reactions appeared to be limited to sulfation of oxisuran alcohol sulfoxides and oxisuran alcohol sulfone. Pharmacokinetics were investigated for oxisuran and its metabolites.

Animals↗
PubMed1977

Amorphous ferrous sulfide as a reducing agent for culture of anaerobes.

Amorphous ferrous sulfide, prepared by reacting ferrous ammonium sulfate and sodium sulfide, is an excellent reducing agent for the culture of anaerobes. It reduces resazurin and reacts much more rapidly with O2 than does either soluble sulfide (HS)- or cysteine. One of the end products of the oxidation of ferrous sulfide with O2 is red and serves as an indicator for the oxygen contamination of a culture medium. Amorphous ferrous sulfide served as a suitable reducing agent for the growth of species of Methanobacterium or Clostridium. Its use is recommended for enrichment or culture of anaerobes (e.g. autotrophs, fermentative organisms) from sediments and other habitats were organic reducing agents are undesirable and where soluble sulfide might be toxic.

Anaerobiosis↗
PubMed1977

Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria.

Eleven of 21 cyanobacteria strains examined are capable of facultative anoxygenic photosynthesis, as shown by their ability to photoassimilate CO2 in the presence of Na2S, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 703-nm light. These include different cyanobacterial types (filamentous and unicellular) of different growth histories (aerobic, anaerobic, and marine and freshwater). Oscillatoria limnetica, Aphanothece halophytica (7418), and Lyngbya (7104) have different optimal concentrations of Na2S permitting CO2 photoassimilation, above which the rate decreases: 3.5, 0.7, and 0.1 mM, respectively. In A. halophytica, for each CO2 molecule photoassimilated two sulfide molecules are oxidized to elemental sulfur, which is excreted from the cells. The ecological and evolutionary significance of anoxygenic photosynthesis in the cyanobacteria is discussed.

Aerobiosis↗
PubMed1978

Enzymatic oxidation of disulfides and thiolsulfinates by both rabbit liver microsomes and a reconstituted system with purified cytochrome P-450.

Both rabbit liver microsomes and reconstituted system with purified cytochrome P-450 and cofactors enzymatically oxidized o-dithiane (1, 2-dithiane), 3-methyl-o-dithiane, thiane and 2-methylthiane to the corresponding mono-oxygenated products; sulfides or disulfides were oxidized to the corresponding sulfoxides or thiosulfinates, while thiosulfinate was oxidized to thiolsulfonate. The reconstituted systems required oxygen and NADPH and were not affected by the catalase which decomposes H2O2, or by 1,4-diazabicyclo-[2,2,2]octane (DABCO), which is a good quencher of singlet oxygen. The differences in the binding of substrates such as sulfides and disulfides with the enzyme system are discussed in connection with differences in the spectra of the substrates in the reconstituted system with pure cytochrome P-450. A correlation was found between the rates of oxidation of the substrates and the rates of oxidation of NADPH.

Animals↗
PubMedDate not supplied

[Sulfate reduction and the water-soluble organic substances in a flooded petroleum bed].

The paper presents the analytical data for the hydrochemical and microbiological composition of the water in a stratum undergoing changes as a result of artificial flooding. The highest accumulation of biogenic H2S and the carbon of dissolved organic substance was found in diluted bed waters with mineralization of 17.17 g/litre. The composition of the bitumen carbon of dissolved organic substances changed with dilution of the stratum brine. The data thus obtained suggest the existence of an indirect relationship; oxidized dissolved organic substance--the rate of sulphate reduction. The nature of organic substance appearing in the petroleum stratum is discussed.

Gram-Negative Chemolithotrophic Bacteria↗
PubMedDate not supplied

[Attachment of Sulfobacillus thermosulfidooxidans cells to the surface of sulfide minerals].

The behaviour of Sulfobacillus thermosulfidooxidans cells in cultures growing at 50 degrees C in the autotrophic conditions with intensive stirring of the medium was studied by phase-contrast and electron microscopy. The following compounds (at a concentration of 1%) were used as an energy source: pyrite, chalcopyrite, arsenopyrite, antimonite, galenite, sphalerite, and copper-zinc-pyrite ore. A considerable part of cells was found to be attached to the surface of crystals in the course of oxidation of the above sulfide minerals. Adhesion of cells to the surface of minerals was accomplished by means of abundant slime formation. The cell produced slime at the highest rate by those parts of its surface which was adjacent to the mineral. Apparently, the chemoreceptor apparatus of the cell was involved in the process of adhesion. Appendages of an unknown nature were found in cells growing on pyrite. Presumably, cells are anchored to the surface of minerals by these structures.

Microscopy, Electron↗
PubMed1979

Structure-function relationship in hemoproteins: the role of cytochrome c3 in the reduction of colloidal sulfur by sulfate-reducing bacteria.

Cytochromes c3 of different strains of sulfate-reducing bacteria have been purified and tested for their capacity to reduce colloidal sulfur to hydrogen sulfide. The results are in good agreement with the activities reported for the whole cells. Cytochrome c3 is the sulfur reductase of some strains of sulfate-reducing bacteria such as Desulfovibrio desulfuricans Norway 4 and sulfate-reducing bacterium strain 9974 from which the sulfur reductase activity can be purified with the cytochrome c3. In contrast, Desulfovibrio vulgaris Hildenborough cytochrome c3 is inhibited by the product of the reaction namely hydrogen sulfide. Chloramphenicol has no effect on the sulfur reductase activity of D. desulfuricans Norway 4 when resting cells grown on lactate-sulfate medium are put in the presence of colloidal sulfur. This shows that the sulfur reductase activity is constitutive and corresponds to the fact that colloidal sulfur grown cells do not contain more cytochrome c3 (or another sulfur reductase) than lactate-sulfate-grown cells.

Chloramphenicol↗
PubMed1977

Oxidation of stibnite by Thiobacillus ferrooxidans.

Optimum pH, temperature and pulp density for microbiological leaching of museum-grade stibnite mineral has been investigated using a stibnite-adapted strain of Thiobacillus ferrooxidans. Optimum conditions were found to be pH 1.75, 35 C and 12g solid substrate per 100 ml of basal salts medium as the initial dose. The energy of activation was determined to be 16.8 kcal per mole, and the temperature coefficient 2.2. The highest total dissolved antimony concentration, [Sbt] = [Sb+3] + [sb+5] + I1SbO2+], was about 1400 mg/litre, due to relatively low solubility of (SbO)2SO4 and (SbO2)2SO4.

Antibodies↗
PubMed1977

Reduction of fensulfothion to fensulfothion sulfide by Klebsiella pneumoniae.

A cell suspension of Klebsiella pneumoniae converted the organophosphorus pesticide fensulfothion to a product that was shown by chemical oxidation, gas-liquid chromatography, infrared spectrophotometry, and mass spectrometry to be fensulfothion sulfide. Further alteration of this metabolite was not noted.

Biodegradation, Environmental↗
PubMed1976

Product analysis of bisulfite reductase activity isolated from Desulfovibrio vulgaris.

Bisulfite reductase was purified from extracts of Desulfovibrio vulgaris. By colorimetric analyses trithionate was found to be the major product, being formed in quantities 5 to 10 times more than two other detectable products, thiosulfate and sulfide. When [35S]bisulfite was used as the substrate, all three products were radioactively labeled. Degradation of [35S]trithionate showed that all of its sulfur atoms were equally labeled. In contrast, [35S]thiosulfate contained virtually all of the radioactivity in the sulfonate atom while the sulfane atom was unlabeled. These results, in conjunction with the funding that the sulfide was radioactive, led to the conclusion that bisulfite reductase reduced bisulfite to trithionate as the major product and sulfide as the minor product; the reason for the unusual labeling pattern found in the thiosulfate molecule was not apparent at this time. When bisulfite reductase was incubated with [35S]bisulfite in the presence of another protein fraction, FII, the thiosulfate formed from this reaction contained both sulfur atoms having equal radioactivity. This discovery, plus the fact that trithionate was not reduced to thiosulfate under identical conditions, led to the speculation that bisulfite could be reduced to thiosulfate by another pathway not involving trithionate.

Cell-Free System↗
PubMed1978

Responses of the a3 component of cytochrome c oxidase to substrate and ligand addition.

We have previously described a transient high spin ferric heme species in cytochrome c oxidase (EC 1.9.3.1) which represent a3+(3) (Beinert, H. and Shaw, R.W.(1977) Biochim. Biophys. Acta 462, 12u--130), and can be detected and quantitatively determined by EPR. We have now used out ability to generate this species to study reactions of a3+(3) with substrates and ligands and also responses to pH changes. This was accomplished by multiple rapid mixing and freezing techniques in conjunction with low temperature EPR and optical reflectance spectroscopies. The substrates used were O2 and ferrocytochrome c and the ligands cyanide, sulfide, azide and carbon monoxide. Contrary to the oxidized, resting form of the enzyme, the transient high spin species of a3+(3) reacts within less than 10 ms stoichiometrically with cyanide and sulfide and at a slower rate with azide. The transient a3+(3) species responds to O2 and CO by changes in signal size or shape, although no oxidoreduction is involved, indicating that a3+(3) registers the presence of these gases. The high spin signal of the transient species is readily abolished by ferrocytochrome c or on raising the pH. Decreasing the pH induces a shift from the rhombic towards the axial component of the signal. Since the responses to CO and pH are analogous for the rhombic transient species to those observed with the rhombic high spin ferric heme species produced on partial reduction, it is suggested that the rhombic signals represent a3+(3) in either case. In all these experiments, in which EPR detectable a3+(3) was observed in large yield, no extra signals for copper or correspondingly increased intensity in the copper signal at g = 2 were seen. The relationship is discussed of the obviously reactive transient species of a3+(3) to other 'activated' species that have been reported and to the oxidized resting form of the enzyme, which is known to react only slowly with ligands and to respond sluggishly to substrate.

Azides↗
PubMed1979

The sulphur cycle: definitions, mechanisms and dynamics.

The principal biochemical processes of the sulphur cycle are described and the types of organisms known to catalyse the reductive and oxidative phases of the cycle outlined. Attention is drawn to the shortcomings in our current knowledge of the scale of turnover of the sulphur cycle and of our understanding of the microorganisms involved in specialized environments. Examples of some special habitats are used to illustrate these points. The role of sulphate-reducing bacteria and sulphur-oxidizing chemolithotrophs in the formation and recycling of sulphide minerals is described.

Aerobiosis↗