Purification and Characterization of an Iron Superoxide Dismutase and a Catalase from the Sulfate-Reducing BacteriumDesulfovibrio gigas

ABSTRACT The iron-containing superoxide dismutase (FeSOD; EC 1.15.1.1 ) and catalase (EC 1.11.1.6 ) enzymes constitutively expressed by the strictly anaerobic bacterium Desulfovibrio gigas were purified and characterized. The FeSOD, isolated as a homodimer of 22-kDa subunits, has a specific activity of 1,900 U/mg and exhibits an electron paramagnetic resonance (EPR) spectrum characteristic of high-spin ferric iron in a rhombically distorted ligand field. Like other FeSODs from different organisms, D. gigas FeSOD is sensitive to H2O2 and azide but not to cyanide. The N-terminal amino acid sequence shows a high degree of homology with other SODs from different sources. On the other hand, D. gigas catalase has an estimated molecular mass of 186 ± 8 kDa, consisting of three subunits of 61 kDa, and shows no peroxidase activity. This enzyme is very sensitive to H2O2and cyanide and only slightly sensitive to sulfide. The native enzyme contains one heme per molecule and exhibits a characteristic high-spin ferric-heme EPR spectrum (g y,x = 6.4, 5.4); it has a specific activity of 4,200 U/mg, which is unusually low for this class of enzyme. The importance of these two enzymes in the context of oxygen utilization by this anaerobic organism is discussed.

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Desulfocarbo indianensis gen. nov., sp. nov., a benzoate-oxidizing, sulfate-reducing bacterium isolated from water extracted from a coal bed

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.064873-0 ◽

2014 ◽

Vol 64 (Pt_8) ◽

pp. 2907-2914 ◽

Cited By ~ 16

Author(s):

Thuy T. An ◽

Flynn W. Picardal

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

16S Rrna Gene Sequencing ◽

Optimal Growth ◽

Coal Bed ◽

Rrna Gene ◽

Strictly Anaerobic ◽

Content Type ◽

Sulfate Reducing ◽

Link Type

A novel, strictly anaerobic, sulfate-reducing bacterium, designated strain SCBMT, was isolated from water extracted from a coal bed in Indiana, USA. The isolate was characterized by a polyphasic taxonomic approach that included phenotypic and genotypic characterizations. Cells of strain SCBMT were vibrio-shaped, polarly flagellated, Gram-negative, motile, oxidase-negative and weakly catalase-positive. Growth of strain SCBMT was observed at NaCl concentrations ranging from 0 to 300 mM. However, no growth was observed when 1 M or more NaCl was present. Growth was observed at 16–37 °C, with optimal growth at 30 °C. The optimum pH for growth was 7, although growth was observed from pH 6.5 to 8. The doubling time under optimal growth conditions (30 °C, pH 7, 2.5 mM benzoate, 14 mM sulfate) was 2.7 days. Bicarbonate, HEPES, PIPES and MES were effective buffers for growth of strain SCBMT, but citrate inhibited growth. When sulfate was provided as the electron acceptor, strain SCBMT grew autotrophically with hydrogen as the electron donor and heterotrophically on benzoate, formate, acetate, pyruvate, butyrate, fumarate, succinate and palmitate. None of the substrates tested supported fermentative growth. Thiosulfate and sulfate were used as electron acceptors coupled to benzoate oxidation, but sulfite, elemental sulfur, DMSO, anthraquinone 2,6-disulfonate, nitrate, nitrite, ferric citrate, hydrous iron oxide and oxygen were not. The G+C content of genomic DNA was 62.5 mol%. The major cellular fatty acids were anteiso-C15 : 0 and C18 : 1ω7c. Phylogenetic analysis based on 16S rRNA gene sequencing placed strain SCBMT into a distinct lineage within the class Deltaproteobacteria . The closest, cultivated phylogenetic relative of strain SCBMT was Desulfarculus baarsii DSM 2075T, with only 91.7 % 16S rRNA gene sequence identity. On the basis of phenotypic and genotypic analyses, strain SCBMT represents a novel genus and species of sulfate-reducing bacteria, for which the name Desulfocarbo indianensis gen. nov., sp. nov. is proposed. The type strain of Desulfocarbo indianensis is SCBMT ( = DSM 28127T = JCM 19826T). Desulfocarbo is the second genus of the order Desulfarculales .

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Reclassification of Desulfobacterium anilini as Desulfatiglans anilini comb. nov. within Desulfatiglans gen. nov., and description of a 4-chlorophenol-degrading sulfate-reducing bacterium, Desulfatiglans parachlorophenolica sp. nov.

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.064360-0 ◽

2014 ◽

Vol 64 (Pt_9) ◽

pp. 3081-3086 ◽

Cited By ~ 50

Author(s):

Daisuke Suzuki ◽

Zhiling Li ◽

Xinxin Cui ◽

Chunfung Zhang ◽

Arata Katayama

Keyword(s):

Type Species ◽

Sequence Similarity ◽

Phylogenetic Analyses ◽

Electron Acceptors ◽

Electron Donors ◽

Rrna Gene ◽

Strictly Anaerobic ◽

Content Type ◽

Sulfate Reducing ◽

Link Type

A strictly anaerobic, mesophilic, sulfate-reducing bacterial strain (DST), isolated from river sediment contaminated with volatile organic compounds, was characterized phenotypically and phylogenetically. Cells were Gram-reaction-negative, non-motile short rods. For growth, optimum NaCl concentration was 0.9 g l−1, optimum temperature was 30 °C and optimum pH was 7.2. Strain DST utilized phenol, benzoate, 4-hydroxybenzoate, 4-methylphenol, 4-chlorophenol, acetate, butyrate and pyruvate as electron donors for sulfate reduction. Electron donors were completely oxidized. Strain DST did not utilize sulfite, thiosulfate or nitrate as electron acceptors. The genomic DNA G+C content of strain DST was 58.9 mol%. Major cellular fatty acids were iso-C14 : 0, anteiso-C15 : 0 and C18 : 1ω7c. Phylogenetic analyses based on the 16S rRNA gene indicated its closest relatives were strains of Desulfobacterium anilini (about 98–99 % sequence similarity) but the DNA–DNA hybridization value with Desulfobacterium anilini Ani1T was around 40 %. Although strain DST and its relatives shared most phenotypic and chemotaxonomic characteristics, the utilization of 4-chlorophenol, the range of electron acceptors and the optimum growth conditions differed. Strain DST is closely related to strains of Desulfobacterium anilini , but constitutes a different species within the genus. Based on phylogeny, phenotypic characteristics and chemotaxonomic characteristics, strain DST and Desulfobacterium anilini were clearly different from strains of other species of the genus Desulfobacterium . We thus propose the reclassification of Desulfobacterium anilini within a new genus, Desulfatiglans gen. nov., as Desulfatiglans anilini comb. nov. We also propose Desulfatiglans parachlorophenolica sp. nov. to accommodate strain DST. The type strain is DST ( = JCM 19179T = DSM 27197T).

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Mössbauer effect in rubredoxin. Determination of the hyperfine field of the iron in a simple iron–sulphur protein

Biochemical Journal ◽

10.1042/bj1291063 ◽

1972 ◽

Vol 129 (5) ◽

pp. 1063-1070 ◽

Cited By ~ 58

Author(s):

K. K. Rao ◽

M. C. W. Evans ◽

R. Cammack ◽

D. O. Hall ◽

C. L. Thompson ◽

...

Keyword(s):

Hyperfine Field ◽

High Spin ◽

Iron Atom ◽

Mössbauer Effect ◽

Photosynthetic Bacterium ◽

Ligand Field ◽

Mossbauer Effect ◽

Orbit Splitting ◽

Paramagnetic Resonance ◽

Fermentative Bacteria

1. Rubredoxin isolated from the green photosynthetic bacterium Chloropseudomonas ethylica was similar in composition to those from anaerobic fermentative bacteria. Amino acid analysis indicated a minimum molecular weight of 6352 with one iron atom per molecule. 2. The circular-dichroism and electron-paramagnetic-resonance spectra of Ch. ethylica rubredoxin showed many similarities to those of Clostridium pasteurianum, but suggested that there may be subtle differences in the protein conformation about the iron atom. 3. Mössbauer-effect measurements on rubredoxin from Cl. pasteurianum and Ch. ethylica showed that in the oxidized state the iron (high-spin Fe3+) has a hyperfine field of 370±3kG, whereas in the reduced state (high-spin Fe2+) the hyperfine field tensor is anisotropic with a component perpendicular to the symmetry axis of the ion of about −200kG. For the reduced protein the sign of the electric-field gradient is negative, i.e. the ground state of the Fe2+is a [unk] orbital. There is a large non-cubic ligand-field splitting (Δ/k=900°K), and a small spin-orbit splitting (D~+4.4cm-1) of the Fe2+levels. 4. The contributions of core polarization to the hyperfine field in the Fe3+and Fe2+ions are estimated to be −370 and −300kG respectively. 5. The significance of these results in interpretation of the Mössbauer spectra of other iron–sulphur proteins is discussed.

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Desulfotomaculum defluvii sp. nov., a sulfate-reducing bacterium isolated from the subsurface environment of a landfill

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.047662-0 ◽

2013 ◽

Vol 63 (Pt_6) ◽

pp. 2290-2295 ◽

Cited By ~ 10

Author(s):

Srinivasan Krishnamurthi ◽

Stefan Spring ◽

Pinnaka Anil Kumar ◽

Shanmugam Mayilraj ◽

Hans-Peter Klenk ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Sequence Similarity ◽

Optimal Growth ◽

Cellular Fatty Acid ◽

Rrna Gene ◽

Strictly Anaerobic ◽

Content Type ◽

Sulfate Reducing ◽

Link Type

A novel sulfate-reducing, strictly anaerobic and endospore-forming bacterium, designated strain A5LFS102T, was isolated from a subsurface landfill sample. The strain was characterized using a polyphasic approach. Optimal growth was observed at 37 °C and pH 7.5 with sulfate as an electron acceptor. Sulfite and thiosulfate were utilized as electron acceptors. The respiratory isoprenoid quinone was menaquinone MK-7. 16S rRNA gene sequence analysis assigned strain A5LFS102T to the genus Desulfotomaculum . Both 16S rRNA and dissimilatory sulfate reductase (dsr) genes were compared with those of representative members of the genus Desulfotomaculum . Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain A5LFS102T was closely related to Desulfotomaculum aeronauticum DSM 10349T (94.6 % sequence similarity). The G+C content of the DNA was 45.4 mol%. The total cellular fatty acid profile was dominated by C16 fatty acids. These phenotypic and genotypic data showed that strain A5LFS102T should be recognized as representative of a novel species of the genus Desulfotomaculum , for which the name Desulfotomaculum defluvii sp. nov. is proposed. The type strain is A5LFS102T ( = DSM 23699T = JCM 14036T = MTCC 7767T).

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Carbonylation as a Key Reaction in Anaerobic Acetone Activation by Desulfococcus biacutus

Applied and Environmental Microbiology ◽

10.1128/aem.02116-13 ◽

2013 ◽

Vol 79 (20) ◽

pp. 6228-6235 ◽

Cited By ~ 12

Author(s):

Olga B. Gutiérrez Acosta ◽

Norman Hardt ◽

Bernhard Schink

Keyword(s):

Mass Spectrometry ◽

Specific Activity ◽

Initial Step ◽

Sulfate Reducing Bacteria ◽

Cell Extract ◽

Strictly Anaerobic ◽

Content Type ◽

Sulfate Reducing ◽

Carbonylation Reaction ◽

Reducing Bacteria

ABSTRACTAcetone is activated by aerobic and nitrate-reducing bacteria via an ATP-dependent carboxylation reaction to form acetoacetate as the first reaction product. In the activation of acetone by sulfate-reducing bacteria, acetoacetate has not been found to be an intermediate. Here, we present evidence of a carbonylation reaction as the initial step in the activation of acetone by the strictly anaerobic sulfate reducerDesulfococcus biacutus. In cell suspension experiments, CO was found to be a far better cosubstrate for acetone activation than CO2. The hypothetical reaction product, acetoacetaldehyde, is extremely reactive and could not be identified as a free intermediate. However, acetoacetaldehyde dinitrophenylhydrazone was detected by mass spectrometry in cell extract experiments as a reaction product of acetone, CO, and dinitrophenylhydrazine. In a similar assay, 2-amino-4-methylpyrimidine was formed as the product of a reaction between acetoacetaldehyde and guanidine. The reaction depended on ATP as a cosubstrate. Moreover, the specific activity of aldehyde dehydrogenase (coenzyme A [CoA] acylating) tested with the putative physiological substrate was found to be 153 ± 36 mU mg−1protein, and its activity was specifically induced in extracts of acetone-grown cells. Moreover, acetoacetyl-CoA was detected (by mass spectrometry) after the carbonylation reaction as the subsequent intermediate after acetoacetaldehyde was formed. These results together provide evidence that acetoacetaldehyde is an intermediate in the activation of acetone by sulfate-reducing bacteria.

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Effect of Thermal Treatment on the EPR Spectrum and on Catalytic Properties of Pure Co3O4

Applied Spectroscopy ◽

10.1366/0003702963904836 ◽

1996 ◽

Vol 50 (11) ◽

pp. 1395-1398 ◽

Cited By ~ 12

Author(s):

C. Oliva ◽

L. Forni ◽

L. Formaro

Keyword(s):

Thermal Treatment ◽

Specific Activity ◽

Temperature Treatment ◽

Epr Spectrum ◽

Exchange Effect ◽

Paramagnetic Resonance ◽

Oxygen Excess ◽

Higher Temperature ◽

Lower Temperature ◽

Electron Paramagnetic

Thermal treatment of Co3O4 decreases the number of cationic vacancies by reducing the oxygen excess in the “as prepared” sample. Correspondingly, a narrower Lorentzian-shaped EPR line is detectable after higher temperature treatment, because of a more efficient Co–O–Co super-exchange effect, favored by the Co2+ enrichment of the sample. Furthermore, the linewidth increases linearly with electron paramagnetic resonance (EPR) recording temperature. We attribute this effect to the onset of antisymmetric exchange in layer-like structures. Catalytic activity tests have been carried out at 323, 373, and 423 K on oxidation of CO by air oxygen as a probe reaction. Samples calcined at 536 and 773 K were tested. Both the catalysts proved to be practically inactive at 323 K. However, at 423 K the specific activity of the catalyst calcined at higher temperature was approximately twice as high as that shown by the sample calcined at lower temperature. Also, this effect has been attributed to the enrichment in Co2+ ions, which would act as catalytic centers when located at the solid surface.

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Desulfoprunum benzoelyticum gen. nov., sp. nov., a Gram-stain-negative, benzoate-degrading, sulfate-reducing bacterium isolated from a wastewater treatment plant

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.066761-0 ◽

2015 ◽

Vol 65 (Pt_1) ◽

pp. 77-84 ◽

Cited By ~ 20

Author(s):

Madan Junghare ◽

Bernhard Schink

Keyword(s):

Fatty Acids ◽

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Type Species ◽

Treatment Plant ◽

Strictly Anaerobic ◽

Gram Stain ◽

Content Type ◽

Sulfate Reducing ◽

Link Type

A strictly anaerobic, mesophilic, sulfate-reducing bacterium, strain KoBa311T, isolated from the wastewater treatment plant at Konstanz, Germany, was characterized phenotypically and phylogenetically. Cells were Gram-stain-negative, non-motile, oval to short rods, 3–5 µm long and 0.8–1.0 µm wide with rounded ends, dividing by binary fission and occurring singly or in pairs. The strain grew optimally in freshwater medium and the optimum temperature was 30 °C. Strain KoBa311T showed optimum growth at pH 7.3−7.6. Organic electron donors were oxidized completely to carbon dioxide concomitant with sulfate reduction to sulfide. At excess substrate supply, substrates were oxidized incompletely and acetate (mainly) and/or propionate accumulated. The strain utilized short-chain fatty acids, alcohols (except methanol) and benzoate. Sulfate and DMSO were used as terminal electron acceptors for growth. The genomic DNA G+C content was 52.3 mol% and the respiratory quinone was menaquinone MK-5 (V-H2). The major fatty acids were C16 : 0, C16 : 1ω7c/ω6c and C18 : 1ω7c. Phylogenetic analysis based on 16S rRNA gene sequences placed strain KoBa311T within the family Desulfobulbaceae in the class Deltaproteobacteria . Its closest related bacterial species on the basis of the distance matrix were Desulfobacterium catecholicum DSM 3882T (93.0 % similarity), Desulfocapsa thiozymogenes (93.1 %), Desulforhopalus singaporensis (92.9 %), Desulfopila aestuarii (92.4 %), Desulfopila inferna JS_SRB250LacT (92.3 %) and Desulfofustis glycolicus (92.3 %). On the basis of phylogenetic, physiological and chemotaxonomic characteristics, strain KoBa311T was distinct from any related type species. Therefore, strain KoBa311T is considered to represent a novel species of a new genus, for which the name Desulfoprunum benzoelyticum gen. nov., sp. nov. is proposed. The type strain of Desulfoprunum benzoelyticum is KoBa311T ( = DSM 28570T = KCTC 15441T).

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Radiation Effects on Hollandite Ceramics developed for Radioactive Cesium Immobilization

MRS Proceedings ◽

10.1557/proc-792-r2.3 ◽

2003 ◽

Vol 792 ◽

Author(s):

V. Aubin ◽

D. Caurant ◽

D. Gourier ◽

N. Baffier ◽

S. Esnouf ◽

...

Keyword(s):

Radiation Effects ◽

Liquid Waste ◽

Fission Products ◽

Radioactive Cesium ◽

Radioactive Liquid Waste ◽

Epr Spectrum ◽

Paramagnetic Resonance ◽

Γ Radiation ◽

The Stability ◽

High Level

ABSTRACTProgress on separating the long-lived fission products from the high level radioactive liquid waste (HLW) has led to the development of specific host matrices, notably for the immobilization of cesium. Hollandite (nominally BaAl2Ti6O16), one of the main phases constituting Synroc, receives renewed interest as specific Cs-host wasteform. The radioactive cesium isotopes consist of short-lived Cs and Cs of high activities and Cs with long lifetime, all decaying according to Cs+→Ba2++e- (β) + γ. Therefore, Cs-host forms must be both heat and (β,γ)-radiation resistant. The purpose of this study is to estimate the stability of single phase hollandite under external β and γ radiation, simulating the decay of Cs. A hollandite ceramic of simple composition (Ba1.16Al2.32Ti5.68O16) was essentially irradiated by 1 and 2.5 MeV electrons with different fluences to simulate the β particles emitted by cesium. The generation of point defects was then followed by Electron Paramagnetic Resonance (EPR). All these electron irradiations generated defects of the same nature (oxygen centers and Ti3+ ions) but in different proportions varying with electron energy and fluence. The annealing of irradiated samples lead to the disappearance of the latter defects but gave rise to two other types of defects (aggregates of light elements and titanyl ions). It is necessary to heat at relatively high temperature (T=800°C) to recover an EPR spectrum similar to that of the pristine material. The stability of hollandite phase under radioactive cesium irradiation during the waste storage is discussed.

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