Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Arthrobacter”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed1983

Action of levan fructotransferase of Arthrobacter ureafaciens on levanoligosaccharides.

Levan fructotransferase of the bacterium Arthrobacter ureafaciens, which produces di-D-fructose 2,6':6,2' dianhydride (difructose anhydride IV) from levan by an intramolecular transfructosylation reaction, was purified to give a single protein band of pI 4.5-4.7 on isoelectric focusing. It had a molecular weight of 128,000 on gel-filtration on Sephadex G-200 and 60,000 on SDS-polyacrylamide disc gel-electrophoresis, suggesting that the enzyme is composed of two identical subunits. The shortest levanoligosaccharide chain required for the difructose anhydride IV formation was determined to be tetraose. TLC of the enzymic digest of a modified levanhexaose derived from levanhexaose by the reduction of the reducing end to an alditol residue with sodium borohydride gave the difructose anhydride IV spot, suggesting that the enzyme attacks the modified levanhexaose molecule from the direction of the non-reducing fructose end. The enzymic digests of levantetraose, -pentaose, and -hexaose as the substrate gave, in addition to the difructose anhydride IV spot, spots of oligofructans of lower mobility than the original substrate on TLC. From the digest of levantetraose, a hexaoligofructan and a smaller amount of a pentaoligofructan but no fructose were separated, indicating enzymic intermolecular levanbiosyl and fructosyl transfer reactions.

Arthrobacter↗
PubMedDate not supplied

[Aqueous petroleum-oxidizing Arthrobacter].

Water petroleum oxidizing bacteria of Arthrobacter ceroformans as well as their lipid composition are described. On a medium containing hexadecane, all the strains produce wax in large amounts (upto 70% of total free lipids) consisting by 95% of cetyl palmitate. Fatty acids are represented mainly by palmitic acid but comprise also unsaturated C16:1 and C18:1 acids. Mycolic acids have not been detected. The significance of lipid composition for the identification of arthrobacteria is discussed.

Arthrobacter↗
PubMedDate not supplied

[Effect of exogenous acetyl group acceptors on cholinesterase biosynthesis in Arthrobacter simplex cells].

The presence of active acetyl or butyryl groups and their acceptors in the growth medium was found to be necessary for the high rate of cholinesterase biosynthesis in the cells of Arthrobacter simplex var. cholinesterasus. The active acetyl and butyryl groups are formed upon hydrolysis of acetylcholine and butyrylcholine as well as in the course of glucose metabolism. The following acids were shown to be the acceptors of the acetyl and butyryl groups: butyric, succinic, fumaric, malic acids and, to a less extent, alpha-ketoglutaric acid. The active acetyl and butyryl groups are bound with the acceptors under the control of coenzyme A in the reactions of fatty acid synthesis and the tricarboxylic acid cycle. Presumably, CoA regulates cholinesterase synthesis. The high rate of CoA binding in metabolic reactions provides conditions for the intensive synthesis of cholinesterase; the deceleration of these reactions inhibits the biosynthesis of cholinesterase.

Acetylation↗
PubMed1982

Substrate and product specificity of Arthrobacter sialophilus neuraminidase.

Arthrobacter sialophilus neuraminidase catalyzes the hydrolysis of N-acetylneuraminyl-alpha-oxygen, nitrogen, and azido glycosides. The most effective of those substrates examined was N-acetylneuraminyl-alpha-4-methylumbelliferylglycoside (AcNeu-alpha-4-MU; Km app, 0.0193 mM; kcat, 136.4 sec-1). The products resulting from the enzymic hydrolysis of N-acetylneuraminyl-alpha-azido-glycoside were N-acetylneuraminic acid and azide ion. N-acetylneuraminyl-alpha-2,3-thiogalactylglycoside and N-acetylneuraminyl-alpha-2,6-thiogalactylglycoside were competitive inhibitors of the enzyme having KI values of 1.52 mM and 1.70 mM, respectively. Dissociation constants for these thioglycosides were also determined by fluorescence enzyme titrations which gave values similar to those determined kinetically. N-Acetylneuraminic acid, but not its methyl ester, was a competitive inhibitor of neuraminidase. Its KI value, 0.18 mM, was also determined by both methods. 5-Acetamido-2,6-anhydro-3,5-dideoxy-D-glycero-D-talo-nonulosonic acid (2-deoxy-4-epi-AcNeu) was found to be a weak competitive inhibitor (KI, 12.1 mM). A. sialophilus neuraminidase further catalyzes transglycosidation reactions with methanol as acceptor. Methanol had no effect on the release of 4-MU by enzymatic hydrolysis of AcNeu-alpha-4-MU, suggesting that the formation of the enzyme-glycone intermediate is the rate-determining step. The anomeric configuration of the product of this reaction, as shown by 13C-nmr spectroscopy, is N-acetylneuraminyl-alpha-methylglycoside. Neuraminidase, therefore, catalyzes its reactions with overall retention of configuration.

Arthrobacter↗
PubMedDate not supplied

[Utilization of 4-chlorobenzoic acid by Arthrobacter globiformis].

A strain of Arthrobacter globiformis utilizing 4-chlorobenzoic acid as a sole source of carbon and energy was isolated by the method of enrichment cultures from vegetable garden soil near Moscow. The yield of released chlorine upon the utilization of 4-chlorobenzoic acid exceeded 96% of the theoretically possible one. Biotin stimulated noticeably the utilization of the acid. The concentration of 4-chlorobenzoic acid that apparently did not inhibit the growth of the isolated organism was within the range of 0.5-0.6 g per litre. The strain utilized a number of mono- and dihydroxybenzoic acids but not benzoic acid. This observation make possible that dehalogenization occurs at the first step of preparative metabolism. The oxidation of 4-chlorobenzoic acid, 4-hydroxybenzoic acid, protocatechuic acid and galactose by the cells grown on these compounds has been studied and shown that the oxidation system for 4-chlorobenzoic acid is an inducible one whereas that for 4-hydroxybenzoic and protocatechuic acids is a constitutive or a semiconstitutive one.

Arthrobacter↗
PubMed1994

Kinetic characterization of tyramine oxidase of Arthrobacter species.

Amine oxidases (EC 1.4.3) represent a rather nebulous group of proteins with relative narrow substrate and inhibitor specificities. Several different enzymes fall into these amine oxidase classes and the classification of some of them still remains ambiguous. Kinetic and physico-chemical properties of tyramine oxidase of Arthrobacter sp. were investigated to decide if this enzyme belongs to the flavin containing tyramine oxidase class (EC 1.4.3.9) or if it is more related to another amine oxidase class. On the basis of its spectral characteristics, molecular weight and inhibition profile, the enzyme was identified as a semicarbazide sensitive copper-containing amine oxidase.

Arthrobacter↗
PubMed1977

Inabilities as an immunoadjuvant of cell walls of the group B peptidoglycan types and those of arthrobacters.

The cell walls from several bacterial species whose peptidoglycans are the group B types (Schleifer and Kandler) and those of two arthrobacters were shown to be inactive or only weakly active as an immunoadjuvant in both induction of delayed-type hypersensitivity and stimulation of circulating antibody levels to ovalbumin when administered to guinea pigs as a water-in-oil emulsion, in sharp contrast to the adjuvant-active cell walls of the group A peptidoglycan types which were previously studied. The possible reason for the inabilities as an adjuvant of these cell walls was discussed in relation to the chemical structures of peptidoglycans.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Oxidation and assimilation pathways of methylated amines in Arthrobacter globiformis].

The oxidation by Arthrobacter globiformis B-175 of tertiary, secondary, and primary amines is catalyzed by specific induced enzymes. Trimethylamine is oxidized to dimethylamine via trimethylamine N-oxide by monooxygenase and demethylase. Dimethylamine is converted to methylamine by another monooxygenase. Methylamine is oxidized to ammonia and formaldehyde by aminoxidase. Formaldehyde is assimilated via ribulose monophosphate cycle, which is confirmed by the presence of hexose-phosphate synthase and by the early and predominant formation of radioactive sugar phosphates during short-term incubation of the cells with labelled methylated amines. Hexose-phosphate synthase was also found in two other strains of A. globiforms (B-126, B-53) which assimilated methylated amines. This methylotroph contains the enzymes of the Krebs cycle which seems to be involved in the synthesis of organic acids. The participation of ammonium nitrogen in anabolic processes is accomplished by reductive amination of alpha-ketoglutarate, glyoxylate, and pyruvate.

Arthrobacter↗
PubMedDate not supplied

[Effect of nitrogen source on growth of Arthrobacter simplex and its biosynthesis of cholinesterase].

The effect of organic and inorganic forms of nitrogen on biomass accumulation and cholinesterase synthesis was studied with Arthrobacter simplex var. cholinesterasus. The culture assimilates nitrogen of ammonium compounds better than other forms of inorganic nitrogen; the best nitrogen source for biosynthesis of cholinesterase is ammonium phosphate. Nitrogen of nitrates is not assimilated. The amount of biomass is almost twice as high on the medium with peptone, casein or casein hydrolysate as on the medium with mineral nitrogen, while the activity of cholinesterase on these nitrogen sources decreases 1.5--2.0 times. Yeast extract as a nitrogen source increases biomass accumulation by a factor of 2.5 and does not supress synthesis of cholinesterase. The concentration of the enzyme synthesized per unit biomass on the medium with yeast extract is the same as on the medium containing ammonium phosphate. The effect of amino acids and amides, i.e. beta-alanine, proline, amides of aspartic and glutamic acids, and their mixtures, is similar to the action of yeast extract: they stimulate biomass accumulation and do not inhibit synthesis of the enzyme. Other amino acids supress synthesis of cholinesterase. The amount of accumulated biomass in the presence of glutamic acid is twice as high as in the case of any other amino acid, and three times as high as on the medium containing ammonium phosphate. Similar action of glutamic acid is manifested when it is used in mixtures with other amino acids. On the medium containing glutamic acid as a sole source of nitrogen, an increase in biomass production is accompanied with a decrease in biosynthesis of the enzyme by 50%. Repression of the biosynthesis is less if glutamic acid is added in mixtures with proline, beta-alanine and asparagine.

Arthrobacter↗
PubMed1998

Crystallization of Arthrobacter sp. strain 1C N-(1-D-carboxyethyl)-L- norvaline dehydrogenase and its complex with NAD+.

The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificities. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 A resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 A and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres.

Arthrobacter↗
PubMed1976

[Degradation of (-)-ephedrine by Arthrobacter globiformis (author's transl)].

A bacterium which grows on and completely degrades ephedrine as the only source of carbon was isolated from soil. This bacterium was identified as Arthrobacter globiformis. From the culture medium the following metabolites were isolated: 1-hydroxy-1-phenyl acetone, benzoic acid, pyrocatechol, cis-cis-muconic acid and methylamine. The mechanism of metabolism is discussed and compared with that in mammals.

Acetone↗
PubMed1998

Removal of nitrate from industrial wastewaters in a pilot plant by nitrate-tolerant klebsiella oxytoca CECT 4460 and arthrobacter globiformis CECT 4500

Two strains, a gram-negative bacterium Klebsiella oxytoca CECT 4460 and a gram-positive, mycelium-forming bacterium Arthrobacter globiformis CECT 4500, tolerant to up to 1 M nitrate, were isolated from the grounds of a munitions factory. Under strict aerobic conditions and with appropriate C-sources, growth of these bacteria took place when the nitrate concentration in the medium was below 150 mM. Optimal growth conditions regarding the culture medium composition for the biological removal of nitrate were established in batch cultures. Then, the system was scaled up to a 40-L pilot plant and operated under continuous conditions in a factory with direct waste streams from dinitroethylene glycol production after appropriate dilution with nontreated groundwaters. The level of nitrate in the effluent was below 0.5% of the initial N-load. Nitrite and ammonium were undetectable and the level of the C-source in the effluent was below 50 mg per L. On the basis of these results, we conclude that the system worked on site satisfactorily. Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed1999

Regulation of lipA gene expression by cell surface proteins in arthrobacter photogonimos

Expression of the light-inducible lipA gene in Arthrobacter photogonimos by photodynamic compounds and visible light was inhibited by washing cells with 1 M KCl. Addition of cell surface extract to KCl-washed cells restored the induction. Washing cells with 1 M MgCl2 removed a 14-kDa polypeptide and concomitantly caused expression of lipA gene without photodynamic treatment. The purified 14-kDa polypeptide inhibited photodynamic induction of lipA gene. These results indicated that regulation of lipA gene expression occurred at the cell surface and involved positive and negative factors, probably through a signal transduction system.

Journal Article↗
PubMed2000

Characteristics of levan fructotransferase from Arthrobacter ureafaciens K2032 and difructose anhydride IV formation from levan.

A microorganism producing levan fructotransferase was isolated from sugar-disclosed soil and it was identified as Arthrobacter ureafaciens. The major product from levan by enzyme reaction was identified as di-D-fructofuranose 2,6':6,2' dianhydride by mass spectrometry, nuclear magnetic resonance, and chemical analyses. Small amounts of several oligosaccharides and free fructose were also formed by enzyme reaction. An extracellular enzyme that produces di-D-fructofuranose 2,6':6,2' dianhydride from levan was purified from the culture broth of A. ureafaciens K2032. The enzyme had optimum activity around pH 5.8 and 45 degrees C and had a dimeric form in solution. The N-terminal amino acid residues of the purified enzyme were SAPGSLRAVYHMTPPSGXLXDPQ. The enzyme has narrow substrate range and converts the levan to di-D-fructofuranose 2,6':6,2' dianhydride with around 62.5% conversion yield.

Journal Article↗
PubMed2001

Optimization of the immobilization parameters and operational stability of immobilized hydantoinase and l-N-carbamoylase from Arthrobacter aurescens for the production of optically pure l-amino acids.

2The immobilization parameters were optimized for the hydantoinase and the L-N-carbamoylase from Arthrobacter aurescens DSM 3747 or 3745, respectively. To optimize activity yields and specific activities for the immobilization to Eupergit C, Eupergit C 250 L, and EAH-Sepharose wild-type, recombinant and genetically modified ('tagged') enzymes were investigated concerning the influence of the protein concentration, the kind of support and the immobilization method. For both enzymes, the use of the recombinant proteins resulted in enhanced specific activities especially when using a hydrophilic support for immobilization such as Sepharose. In the case of a genetically modified hydantoinase carrying a His(6)-tag, affinity coupling led to a loss of activity of higher than 80%. Both enzymes were significantly stabilized by immobilization: In packed bed reactors, Eupergit C 250 L (NH(2))-immobilized hydantoinase and EAH-Sepharose-immobilized L-N-carbamoylase showed half-life times of approx. 14000 and 900 hours, respectively. Together with specific activities of the immobilized enzymes of 2.5 U/g wet carrier (hydantoinase) and 10 U/g wet carrier (L-N-carbamoylase) the newly developed biocatalysts are sufficient to fulfill industrial requirements.In comparison to the free enzymes, temperature and pH-optima were increased by 10 degrees C and one pH unit, respectively, after immobilization. The pH and temperature optima of the hydantoinase (L-N-carbamoylase) were determined to be pH 8.5-10 (pH 9.5) and 45-60 degrees C (60 degrees C).In order to provide sufficient amounts of biocatalyst for the process development in mini plant scale, a 50 fold scale-up of the optimized immobilization procedure was carried out for both enzymes. Because of the overlapping optima, both immobilized enzymes can be operated together in one reactor.

Journal Article↗
PubMed2000

Plate assay for endo-beta-N-acetylglucosaminidase activity using a chromogenic substrate synthesized by transglycosylation with Arthrobacter endo-beta-N-acetylglucosaminidase.

The transglycosylation activity of Arthrobacter endo-beta-N-acetylglucosaminidase (Endo-A) was used for the enzymatic synthesis of a novel oligosaccharide, Man6GlcNAc-5-bromo-4-chloro-3-indolyl-beta-glucoside (Man6GlcNAc-Glc-beta-X). Various endo-beta-N-acetylglucosaminidases hydrolyzed this oligosaccharide, producing Man6GlcNAc and Glc-beta-X. The E. coli strains coexpressing Endo-A and beta-glucosidase formed blue colonies in the presence of Man6GlcNAc-Glc-beta-X. Therefore, endo-beta-N-acetylglucosaminidase activity could be directly detected by the plate assay. This simple plate assay is useful for screening microorganisms for endo-beta-N-acetylglucosaminidase activity.

Journal Article↗
PubMed2004

Cloning and heterologous expression of a glucodextranase gene from Arthrobacter globiformis I42, and experimental evidence for the catalytic diad of the recombinant enzyme.

The gene encoding a glucodextranase from Arthrobacter globiformis I42 was cloned and, subsequently, heterologously expressed in Escherichia coli. This glucodextranase gene consists of 1048 amino acid residues with a calculated molecular mass of 109,135 Da. The roles of two residues at the active site of A. globiformis I42 glucodextranase were examined by site-directed mutagenesis. Glutamic acid residues 458 and 656, which are part of the apparent catalytic residues, were found to be essential for hydrolase activity.

Journal Article↗
PubMed2004

Cloning and heterologous expression of a beta-fructofuranosidase gene from Arthrobacter globiformis IFO 3062, and site-directed mutagenesis of the essential aspartic acid and glutamic acid of the active site.

We have cloned the gene encoding a beta-fructofuranosidase from Arthrobacter globiformis IFO 3062, and subsequently, the gene was heterologously expressed in Escherichia coli. This beta-fructofuranosidase gene encodes a protein of 548 amino acid residues with a calculated molecular mass of 60,519 Da. We have examined the roles of three residues of A. globiformis IFO 3062 beta-fructofuranosidase by site-directed mutagenesis, and found that aspartic acid 130 and glutamic acid 392, which are two of the apparent catalytic residues, are essential for hydrolase activity. This study provides the first experimental evidence showing that these two amino acid residues of beta-fructofuranosidase play a critical role in hydrolyzing sucrose.

Journal Article↗