The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Ortwin Meyer - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of Xanthine Dehydrogenase from the Anaerobic Bacterium Veillonella atypica and Identification of a Molybdopterin‐Cytosine‐Dinucleotide‐Containing Molybdenum Cofactor
European journal of biochemistry, 1996Co-Authors: Lothar Gremer, Ortwin MeyerAbstract:The molybdenum-containing iron-sulfur flavoprotein xanthine dehydrogenase from the Anaerobic Bacterium Veillonella atypica has been purified approximately 800-fold with a yield of approximately 40% and a specific activity of approximately 70 μmol ferricyanide reduced · min−1· mg protein−1 with xanthine as electron donor, which corresponds to approximately 30 μmol xanthine oxidized · min−1· mg protein−1 with methylene blue as electron acceptor. The 129-kDa enzyme was a non-covalent heterotrimer with large (82.4 kDa), medium (28.5 kDa) and small (18.4 kDa) subunits. The N-termini of the small and medium polypeptides of V. atypica xanthine dehydrogenase and the corresponding domains of eukaryotic xanthine dehydrogenases were similar, whereas the N-terminus of the large polypeptide was unrelated to eukaryotic xanthine dehydrogenases. The enzyme contained 0.86 atoms Mo, 1.75 atoms Fe, 1.61 atoms acid-labile sulfur and 0.68 molecules FAD/molecule, which corresponds to a 1:2.0:1.9:0.8 molar ratio. Acid hydrolysis revealed 0.95 mol CMP and 0.80 mol AMP/mol xanthine dehydrogenase. After treatment of the enzyme with iodoacetamide, di(carboxamidomethyl)molybdopterin cytosine dinucleotide was identified, which indicates that molybdopterin cytosine dinucleotide is the organic portion of the V. atypica xanthine dehydrogenase molybdenum cofactor. The enzyme and its molybdenum cofactor occurred in a 1:1 molar ratio. Xanthine dehydrogenases from eukaryotic sources are characterized by a domain structure and the presence of duplicate copies of two types of [2Fe-2S] clusters. In contrast, the xanthine dehydrogenase from V. atypica had a heterotrimeric subunit structure and a single [2Fe-2S] cluster. In addition, the enzyme indicates the presence of a molybdopterin dinucleotide as a constituent of a xanthine dehydrogenase molybdenum cofactor.
-
characterization of xanthine dehydrogenase from the Anaerobic Bacterium veillonella atypica and identification of a molybdopterin cytosine dinucleotide containing molybdenum cofactor
FEBS Journal, 1996Co-Authors: Lothar Gremer, Ortwin MeyerAbstract:The molybdenum-containing iron-sulfur flavoprotein xanthine dehydrogenase from the Anaerobic Bacterium Veillonella atypica has been purified approximately 800-fold with a yield of approximately 40% and a specific activity of approximately 70 μmol ferricyanide reduced · min−1· mg protein−1 with xanthine as electron donor, which corresponds to approximately 30 μmol xanthine oxidized · min−1· mg protein−1 with methylene blue as electron acceptor. The 129-kDa enzyme was a non-covalent heterotrimer with large (82.4 kDa), medium (28.5 kDa) and small (18.4 kDa) subunits. The N-termini of the small and medium polypeptides of V. atypica xanthine dehydrogenase and the corresponding domains of eukaryotic xanthine dehydrogenases were similar, whereas the N-terminus of the large polypeptide was unrelated to eukaryotic xanthine dehydrogenases. The enzyme contained 0.86 atoms Mo, 1.75 atoms Fe, 1.61 atoms acid-labile sulfur and 0.68 molecules FAD/molecule, which corresponds to a 1:2.0:1.9:0.8 molar ratio. Acid hydrolysis revealed 0.95 mol CMP and 0.80 mol AMP/mol xanthine dehydrogenase. After treatment of the enzyme with iodoacetamide, di(carboxamidomethyl)molybdopterin cytosine dinucleotide was identified, which indicates that molybdopterin cytosine dinucleotide is the organic portion of the V. atypica xanthine dehydrogenase molybdenum cofactor. The enzyme and its molybdenum cofactor occurred in a 1:1 molar ratio. Xanthine dehydrogenases from eukaryotic sources are characterized by a domain structure and the presence of duplicate copies of two types of [2Fe-2S] clusters. In contrast, the xanthine dehydrogenase from V. atypica had a heterotrimeric subunit structure and a single [2Fe-2S] cluster. In addition, the enzyme indicates the presence of a molybdopterin dinucleotide as a constituent of a xanthine dehydrogenase molybdenum cofactor.
Garabed Antranikian - One of the best experts on this subject based on the ideXlab platform.
-
Heterologous expression and characterization of a novel branching enzyme from the thermoalkaliphilic Anaerobic Bacterium Anaerobranca gottschalkii
Applied microbiology and biotechnology, 2006Co-Authors: Volker Thiemann, Bodo Saake, Angela Vollstedt, Thomas Schäfer, Jürgen Puls, Costanzo Bertoldo, Roland Freudl, Garabed AntranikianAbstract:The gene encoding the branching enzyme (BE) from the thermoalkaliphilic, Anaerobic Bacterium Anaerobranca gottschalkii was fused with a twin arginine translocation protein secretory-pathway-dependent signal sequence from Escherichia coli and expressed in Staphylococcus carnosus. The secreted BE was purified using hydrophobic interaction and gel filtration chromatography. The monomeric enzyme (72 kDa) shows maximal activity at 50 degrees C and pH 7.0. With amylose the BE displays high transglycosylation and extremely low hydrolytic activity. The conversion of amylose and linear dextrins was analysed by applying high-performance anion exchange chromatography and quantitative size-exclusion chromatography. Amylose (10(4)-4 x 10(7) g/mol) was converted to a major extent to products displaying molecular masses of 10(4)-4 x 10(5) g/mol, indicating that the enzyme could be applicable for the production of starch or dextrins with narrow molecular mass distributions. The majority of the transferred oligosaccharides, determined after enzymatic hydrolysis of the newly synthesized alpha-1,6 linkages, ranged between 10(3) and 10(4) g/mol, which corresponds to a degree of polymerisation (DP) of 6-60. The minimal donor chain length is DP 16. Furthermore, the obtained results support the hypotheses of a random endocleavage mechanism of BE and the occurrence of interchain branching.
-
Purification and Properties of a Thermostable Pullulanase from a Newly Isolated Thermophilic Anaerobic Bacterium, FervidoBacterium pennavorans Ven5.
Applied and environmental microbiology, 1997Co-Authors: R Koch, F. Canganella, Hans Hippe, K D Jahnke, Garabed AntranikianAbstract:Extremely thermophilic Anaerobic fermentative bacteria growing at temperatures between 50 and 80(deg)C (optimum, 65 to 70(deg)C) were isolated from mud samples collected at Abano Terme spa (Italy). The cells were gram-negative motile rods, about 1.8 (mu)m in length and 0.6 (mu)m in width, occurring singly and in pairs. Cells commonly formed spheroids at one end similar to FervidoBacterium islandicum and FervidoBacterium nodosum. The new isolate differs from F. nodosum by the 7% higher G+C content of its DNA (40.6 mol%) but is similar to FervidoBacterium pennavorans and F. islandicum in its G+C content and phenotypic properties. The phylogenetic dendrogram indicates that strain Ven5 belongs to the order Thermotogales and shows the highest 16S ribosomal DNA sequence similarity to F. pennavorans, F. islandicum, and F. nodosum, with similarities of 99.0, 98.6, and 96.0%, respectively. During growth on starch the strain produced a thermostable pullulanase of type I which preferentially hydrolyzed (alpha)-1,6 glucosidic linkages. The enzyme was purified 65-fold by anion-exchange, gel permeation, and hydrophobic chromatography. The native pullulanase has a molecular mass of 240,000 Da and is composed of three subunits, each with a molecular mass of 77,600 Da as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Optimal conditions for the activity and stability of the purified pullulanase were pH 6.0 and 85(deg)C. At pH 6.0, the half-life of the enzyme was over 2 h at 80(deg)C and 5 min at 90(deg)C. This is the first report on the presence of pullulanase type I in an Anaerobic Bacterium.
-
Growth and production of xylanolytic enzymes by the extreme thermophilic Anaerobic Bacterium Thermotoga thermarum
Applied Microbiology and Biotechnology, 1996Co-Authors: Anwar Sunna, Garabed AntranikianAbstract:Cultivation of the extreme thermophilic Anaerobic Bacterium Thermotoga thermarum at 77°C on xylan was accompanied by the formation of heat-stable endoxylanase (136U/l), β-xylosidase (44U/l) and α-arabinofuranosidase (10U/l). These enzymes were mainly associated with the cells and could not be released by detergent treatment {0.1–1.0mM 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulphonate (CHAPS)}. Endoxylanases with a molecular weight of 40, 83 and 100kDa were induced when xylan or xylose were used as substrates for growth. In the presence of other sugars like glucose, maltose, arabinose or starch, low concentrations of the low-molecular-weight endoxylanase (40kDa) was detected. Xylose was found to be the best substrate for the induction of β-xylosidase and α-arabinofuranosidase but not for growth. Cultivation of T. thermarum in a dialysis batch fermentor resulted in a significant increase in cell concentration and enzyme level. A total cell count of 1.3×109 cells/ml and 202U/l of endoxylanase were measured when partially soluble birchwood xylan was used as the carbon source. The use of insoluble beechwood xylan as the substrate caused the elevation of the maximal cell concentration and enzyme level up to 2.0×109 cells/ml and 540U/l, respectively.
Lingwei Ruan - One of the best experts on this subject based on the ideXlab platform.
-
Thermophagus xiamenensis gen. nov., sp. nov., a moderately thermophilic and strictly Anaerobic Bacterium isolated from hot spring sediment.
International journal of systematic and evolutionary microbiology, 2012Co-Authors: Zhaoming Gao, Xin Liu, Xi-ying Zhang, Lingwei RuanAbstract:A moderately thermophilic and strictly Anaerobic Bacterium, designated HS1(T), was isolated from offshore hot spring sediment in Xiamen, China. Cells were Gram-negative, catalase-positive, oxidase-negative, slender and flexible rods without flagella. The strain could grow at 35-55 °C (optimum at 50 °C) and in 1-8 % NaCl (w/v; optimum 2-4 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain HS1(T) was affiliated with the family Marinilabiliaceae and shared a distant relationship with the previously described genera. The isolate was most closely related to Anaerophaga thermohalophila Fru22(T) with 16S rRNA gene sequence similarity of 92.4 %, followed by the other members of the family Marinilabiliaceae with 88.7-91.1 % similarity. The dominant cellular fatty acids were iso-C(15 : 0) and anteiso-C(15 : 0). The predominant quinone was MK-7. The major polar lipids were phosphatidylethanolamine (PE) and an unknown polar lipid. The genomic DNA G+C content was 38.7 mol%. Besides the phylogenetically distant relationship, strain HS1(T) was obviously distinguished from the most closely related genera in several phenotypic properties including colony colour and pigment production, optimal temperature, optimal NaCl, relation to O(2), bicarbonate/carbonate requirement, catalase activity, nitrate reduction, fermentation products and cellular fatty acid profile. Based on the phenotypic and phylogenetic data, strain HS1(T) represents a novel species of a new genus, for which the name Thermophagus xiamenensis gen. nov., sp. nov. is proposed. The type strain of the type species is HS1(T) (= DSM 19012(T) = CGMCCC 1.5071(T)).
-
Genome Sequence of Anaerophaga sp. Strain HS1, a Novel, Moderately Thermophilic, Strictly Anaerobic Bacterium Isolated from Hot Spring Sediment
Journal of bacteriology, 2011Co-Authors: Zhaoming Gao, Xin Liu, Lingwei RuanAbstract:Anaerophaga sp. strain HS1 was isolated from offshore hot spring sediment in Xiamen, China. It was identified as a novel, moderately thermophilic, strictly Anaerobic Bacterium affiliated with the family Marinilabiaceae and showed xylanase activity. Here, we describe the 3.88-Mb draft genome sequence of Anaerophaga sp. strain HS1 and the annotation analysis of related xylanase genes.
Zouhaier Ben Ali Gam - One of the best experts on this subject based on the ideXlab platform.
-
Mobilisporobacter senegalensis gen. nov., sp nov., an Anaerobic Bacterium isolated from tropical shea cake
International Journal of Systematic and Evolutionary Microbiology, 2016Co-Authors: Malick Mbengue, Abdoulaye Thioye, Marc Labat, Laurence Casalot, Manon Joseph, Abdoulaye Samb, Zouhaier Ben Ali GamAbstract:A Gram-stain positive, endospore-forming, strictly Anaerobic Bacterium, designated strain Gal1(T), was isolated from shea cake, a waste material from the production of shea butter, originating from Saraya, Senegal. The cells were rod-shaped, slightly curved, and motile with peritrichous flagella. The strain was oxidase-negative and catalase-negative. Growth was observed at temperatures ranging from 15 to 45 degrees C (optimum 30 degrees C) and at pH 6.5-9.3 (optimum pH 7.8). The salinity range for growth was 0-3.5 % NaCl (optimum 1 %). Yeast extract was required for growth. Strain Gal1(T) fermented various carbohydrates such as mannose, mannitol, arabinose, cellobiose, fructose, glucose, maltose, sucrose, trehalose and lactose and the major end-products were ethanol and acetate. The only major cellular fatty acid was C16 : 0 (19.6 %). The DNA base G+ C content of strain Gal1(T) was 33.8 mol%. Analysis of the 16S rRNA gene sequence of the isolate indicated that this strain was related to Mobilitalea sibirica DSM 26468(T) with 94.27 % similarity, Clostridium populeti ATTC 35295(T) with 93.94 % similarity, and Clostridium aminovalericum DSM 1283(T) and Anaerosporobacter mobilis DSM 15930(T) with 93.63 % similarity. On the basis of phenotypic characteristics, phylogenetic analysis and the results of biochemical and physiological tests, strain Gal1(T) was clearly distinguished from closely related genera, and strain Gal1(T) can be assigned to a novel species of a new genus for which the name Mobilisporobacter senegalensis gen. nov., sp. nov. is proposed. The type strain is Gal1(T) (5DSM 26537(T) 5JCM 18753(T)).
-
Mobilisporobacter senegalensis gen. nov., sp. nov., an Anaerobic Bacterium isolated from tropical shea cake.
International journal of systematic and evolutionary microbiology, 2016Co-Authors: Malick Mbengue, Abdoulaye Thioye, Marc Labat, Laurence Casalot, Manon Joseph, Abdoulaye Samb, Zouhaier Ben Ali GamAbstract:A Gram-stain positive, endospore-forming, strictly Anaerobic Bacterium, designated strain Gal1T, was isolated from shea cake, a waste material from the production of shea butter, originating from Saraya, Senegal. The cells were rod-shaped, slightly curved, and motile with peritrichous flagella. The strain was oxidase-negative and catalase-negative. Growth was observed at temperatures ranging from 15 to 45 °C (optimum 30 °C) and at pH 6.5–9.3 (optimum pH 7.8). The salinity range for growth was 0–3.5 % NaCl (optimum 1 %). Yeast extract was required for growth. Strain Gal1T fermented various carbohydrates such as mannose, mannitol, arabinose, cellobiose, fructose, glucose, maltose, sucrose, trehalose and lactose and the major end-products were ethanol and acetate. The only major cellular fatty acid was C16 : 0 (19.6 %). The DNA base G+C content of strain Gal1T was 33.8 mol%. Analysis of the 16S rRNA gene sequence of the isolate indicated that this strain was related to Mobilitalea sibirica DSM 26468T with 94.27 % similarity, Clostridium populeti ATTC 35295T with 93.94 % similarity, and Clostridium aminovalericum DSM 1283T and Anaerosporobacter mobilis DSM 15930T with 93.63 % similarity. On the basis of phenotypic characteristics, phylogenetic analysis and the results of biochemical and physiological tests, strain Gal1T was clearly distinguished from closely related genera, and strain Gal1T can be assigned to a novel species of a new genus for which the name Mobilisporobacter senegalensis gen. nov., sp. nov. is proposed. The type strain is Gal1T ( = DSM 26537T = JCM 18753T).
Lothar Gremer - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of Xanthine Dehydrogenase from the Anaerobic Bacterium Veillonella atypica and Identification of a Molybdopterin‐Cytosine‐Dinucleotide‐Containing Molybdenum Cofactor
European journal of biochemistry, 1996Co-Authors: Lothar Gremer, Ortwin MeyerAbstract:The molybdenum-containing iron-sulfur flavoprotein xanthine dehydrogenase from the Anaerobic Bacterium Veillonella atypica has been purified approximately 800-fold with a yield of approximately 40% and a specific activity of approximately 70 μmol ferricyanide reduced · min−1· mg protein−1 with xanthine as electron donor, which corresponds to approximately 30 μmol xanthine oxidized · min−1· mg protein−1 with methylene blue as electron acceptor. The 129-kDa enzyme was a non-covalent heterotrimer with large (82.4 kDa), medium (28.5 kDa) and small (18.4 kDa) subunits. The N-termini of the small and medium polypeptides of V. atypica xanthine dehydrogenase and the corresponding domains of eukaryotic xanthine dehydrogenases were similar, whereas the N-terminus of the large polypeptide was unrelated to eukaryotic xanthine dehydrogenases. The enzyme contained 0.86 atoms Mo, 1.75 atoms Fe, 1.61 atoms acid-labile sulfur and 0.68 molecules FAD/molecule, which corresponds to a 1:2.0:1.9:0.8 molar ratio. Acid hydrolysis revealed 0.95 mol CMP and 0.80 mol AMP/mol xanthine dehydrogenase. After treatment of the enzyme with iodoacetamide, di(carboxamidomethyl)molybdopterin cytosine dinucleotide was identified, which indicates that molybdopterin cytosine dinucleotide is the organic portion of the V. atypica xanthine dehydrogenase molybdenum cofactor. The enzyme and its molybdenum cofactor occurred in a 1:1 molar ratio. Xanthine dehydrogenases from eukaryotic sources are characterized by a domain structure and the presence of duplicate copies of two types of [2Fe-2S] clusters. In contrast, the xanthine dehydrogenase from V. atypica had a heterotrimeric subunit structure and a single [2Fe-2S] cluster. In addition, the enzyme indicates the presence of a molybdopterin dinucleotide as a constituent of a xanthine dehydrogenase molybdenum cofactor.
-
characterization of xanthine dehydrogenase from the Anaerobic Bacterium veillonella atypica and identification of a molybdopterin cytosine dinucleotide containing molybdenum cofactor
FEBS Journal, 1996Co-Authors: Lothar Gremer, Ortwin MeyerAbstract:The molybdenum-containing iron-sulfur flavoprotein xanthine dehydrogenase from the Anaerobic Bacterium Veillonella atypica has been purified approximately 800-fold with a yield of approximately 40% and a specific activity of approximately 70 μmol ferricyanide reduced · min−1· mg protein−1 with xanthine as electron donor, which corresponds to approximately 30 μmol xanthine oxidized · min−1· mg protein−1 with methylene blue as electron acceptor. The 129-kDa enzyme was a non-covalent heterotrimer with large (82.4 kDa), medium (28.5 kDa) and small (18.4 kDa) subunits. The N-termini of the small and medium polypeptides of V. atypica xanthine dehydrogenase and the corresponding domains of eukaryotic xanthine dehydrogenases were similar, whereas the N-terminus of the large polypeptide was unrelated to eukaryotic xanthine dehydrogenases. The enzyme contained 0.86 atoms Mo, 1.75 atoms Fe, 1.61 atoms acid-labile sulfur and 0.68 molecules FAD/molecule, which corresponds to a 1:2.0:1.9:0.8 molar ratio. Acid hydrolysis revealed 0.95 mol CMP and 0.80 mol AMP/mol xanthine dehydrogenase. After treatment of the enzyme with iodoacetamide, di(carboxamidomethyl)molybdopterin cytosine dinucleotide was identified, which indicates that molybdopterin cytosine dinucleotide is the organic portion of the V. atypica xanthine dehydrogenase molybdenum cofactor. The enzyme and its molybdenum cofactor occurred in a 1:1 molar ratio. Xanthine dehydrogenases from eukaryotic sources are characterized by a domain structure and the presence of duplicate copies of two types of [2Fe-2S] clusters. In contrast, the xanthine dehydrogenase from V. atypica had a heterotrimeric subunit structure and a single [2Fe-2S] cluster. In addition, the enzyme indicates the presence of a molybdopterin dinucleotide as a constituent of a xanthine dehydrogenase molybdenum cofactor.
