Showing papers on "Arthrobacter published in 1994"

Biodegradation of p-nitrophenol via 1,2,4-benzenetriol by an Arthrobacter sp.

Abstract: The degradation of p-nitrophenol (PNP) by Moraxella and Pseudomonas spp involves an initial monooxygenase-catalyzed removal of the nitro group The resultant hydroquinone is subject to ring fission catalyzed by a dioxygenase enzyme We have isolated a strain of an Arthrobacter sp, JS443, capable of degrading PNP with stoichiometric release of nitrite During induction of the enzymes required for growth on PNP, 1,2,4-benzenetriol was identified as an intermediate by gas chromatography-mass spectroscopy (GC-MS) and radiotracer studies 1,2,4-Benzenetriol was converted to maleylacetic acid, which was further degraded by the beta-ketoadipate pathway Conversion of PNP to 1,2,4-benzenetriol is catalyzed by a monooxygenase system in strain JS443 through the formation of 4-nitrocatechol, 4-nitroresorcinol, or both Our results clearly indicate the existence of an alternative pathway for the biodegradation of PNP

Characterization of a psychrotrophic Arthrobacter gene and its cold-active beta-galactosidase

Abstract: Enzymes with high specific activities at low temperatures have potential uses for chemical conversions when low temperatures are required, as in the food industry. Psychrotrophic microorganisms which grow at low temperatures may be a valuable source of cold-active enzymes that have higher activities at low temperatures than enzymes found for mesophilic microorganisms. To find cold-active beta-galactosidases, we isolated and characterized several psychrotrophic microorganisms. One isolate, B7, is an Arthrobacter strain which produces beta-galactosidase when grown in lactose minimal media. Extracts have a specific activity at 30 degrees C of 2 U/mg with o-nitrophenyl-beta-D-galactopyranoside as a substrate. Two isozymes were detected when extracts were subjected to electrophoresis in a nondenaturing polyacrylamide gel and stained for activity with 5-bromo-4-chloro-indolyl-beta-D-galactopyranoside (X-Gal). When chromosomal DNA was prepared and transformed into Escherichia coli, three different genes encoding beta-galactosidase activity were obtained. We have subcloned and sequenced one of these beta-galactosidase genes from the Arthrobacter isolate B7. On the basis of amino acid sequence alignment, the gene was found to have probable catalytic sites homologous to those from the E. coli lacZ gene. The gene encoded a protein of 1,016 amino acids with a predicted molecular mass of 111 kDa. The enzyme was purified and characterized. The beta-galactosidase from isolate B7 has kinetic properties similar to those of the E. coli lacZ beta-galactosidase but has a temperature optimum 20 degrees C lower than that of the E. coli enzyme.

Characterization of psychrotrophic microorganisms producing beta-galactosidase activities.

Abstract: Investigations of psychrotrophic microorganisms have been limited even though the dominant environment of the Earth is cold and enzymes with high activities at low temperatures could have commercial uses. We have isolated and characterized three psychrotrophic strains with beta-galactosidase activities. The isolates, B7, D2, and D5, were gram-positive, catalase-positive, obligate aerobes. Cells observed with a scanning electron microscope appeared as rods during the early stages of growth but became coccoid during the stationary phase. An analysis of the amino acid composition of the cell walls demonstrated the presence of lysine as the predominant diamino acid in all three isolates. The cell cycle morphology and cell wall composition suggest that the three isolates are members of the genus Arthrobacter. The beta-galactosidase activities in whole cells were labile when incubated at 40 degrees C and had temperature optima about 20 degrees C below that of the enzyme encoded by the lacZ gene of Escherichia coli. Electrophoresis of extracts from the isolates in nondenaturing polyacrylamide gels detected at least two protein bands that hydrolyzed 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal), suggesting the presence of beta-galactosidase isozymes. Images

Degradation of pyridine by Arthrobacter crystallopoietes and Rhodococcus opocus strains

Abstract: Two pyridine-degrading microorganisms Arthrobacter crystallopoietes (VKM Ac-1334D) and Rhodococcus opacus (VKM Ac-1333D) were isolated from soil. The Gas chromatography-mass spectroscopy analysis showed that the former species formed 3-hydroxypyridine, 2,3- and 2,6-dihydroxypyridines during its growth in media containing pyridine, while the latter formed 2-hydroxy- and 2,6-dihydroxypyridines as degradation intermediates. Products of the pyridine ring cleavage (5-amino-2-oxo-4-pentenoic acid and 3-pentenoic acid monoamide) were also detected.

Excretion of nitrogen and phosphorus by the soil ciliate Colpoda steinii when fed the soil bacterium Arthrobacter sp.

Abstract: Nitrogenous excretion of Colpoda steinii Maupas was investigated when this ciliate was fed the soil bacterium, Arthrobacter sp. NCIMB strain 10683, in batch cultures. Pure bacterial cultures were first grown to steady state in a chemostat before the cells were harvested and added to the batch cultures with C. steinii . Ammonium was the major form of N excreted. Ciliate excretion was influenced by the temperature of the culture medium. Ammonium excretion by C. steinii when fed N-replete Arthrobacter sp. (8.5% N, C:N = 5.0) was more rapid at 15°C than at either 10° or 5°C. At 5°C, few ciliate trophozoites were present after 10 days and most of the NH + 4 -N released into the medium at this temperature was probably due to lysis of the ciliates. The N content of the bacterial prey also influenced ciliate excretion. When the ciliates were fed N-limited Arthrobacter sp. (4.1% N, C:N = 8.6) at 10°C, there was an initial lag of 2 days when no N was excreted and the final quantity of N released into the culture medium after 14 days was only 60% of that released when the ciliates were fed the same bacterial strain with a larger N content (8.5% N, C:N = 5.0). In a comparison made between feeding C. steinii on P-limited (0.46% P, C:P = 101) and P-replete (1.72% P, C:P = 26) Arthrobacter sp., P was only mineralized with the latter. Ciliate populations supplied with P-limited Arthrobacter sp., however, declined from the onset of the experiment and few trophozoites or cysts were present after 14 days. An experiment with C. steinii grown actively in the second vessel of a two-stage chemostat, successively using P-replete (1.72% P) and P-limited (0.46% P) Arthrobacter sp., confirmed that the P content of the prey influenced the quantity of P released by C. steinii .

Purification of Inulin Fructotransferase (DFA I-producing) from Arthrobacter sp.MCI2493 and Production of DFA I from Inulin by the Enzyme

Abstract: An extracellular enzyme that produces di-D-fructofuranose-2',1;2,1' dianhydride from inulin was purified from the culture broth of Arthrobacter sp. MCI2493. The molecular weight of the enzyme was 40,000 by gel filtration and SDS polyacrylamide gel electrophoresis. The enzyme had maximum activity at pH 6.0 and 50 degrees C. Using this purified enzyme, 100 g/liter inulin was converted into 60 g/liter of DFA I, nystose, and 1-F-fructofuranosyl-nystose after incubation for 30 h.

Microbially mediated degradation of nitrogen-containing phenol compounds by single bacterial isolates

Abstract: The invention relates to Arthrobacter bacterial isolates capable of degrading picric acid and related compounds to the point where no aromatic ring-containing degradation products can be detected, as determined by HPLC profiles, UV-V spectrometry, analysis of total organic carbon and mineralization of 14 C-picric acid. The isolates were derived from enrichments of bacterial cultures from waste sludge by successive subculturing into medium containing picric acid as the only carbon source.

Purification and characterization of a pyrrole-2-carboxylate oxygenase from Arthrobacter strain Py1

Abstract: Pyrrole-2-carboxylate oxygenase was purified 8.2-fold to homogeneity from Arthrobacter strain Py1 grown on pyrrole-2-carboxylate as sole carbon, nitrogen, and energy source. FAD and dithioerythritol had to be present during the purification procedure to stabilize the enzyme activity. The molecular mass of the pyrrole-2-carboxylate oxygenase was about 160 kDa by gel filtration chromatography and native gradient PAGE, only one polypeptide of about 60 kDa was present after SDS-PAGE. The FAD content was 2.7 to 3.6 mol FAD per enzyme (160 kDa). The non-covalently bound FAD of the pyrrole-2-carboxylate oxygenase was reduced by NADH and reoxidized by oxygen and pyrrole-2-carboxylate. The enzyme exhibited a narrow substrate specificity. Besides pyrrole-2-carboxylate, only pyrrole, pyrrole-2-aldehyde, and indole-2-carboxylate stimulated the oxygen consumption at a very low rate. The enzyme activity was strongly reduced by different sulfhydryl group inhibitors, but it could be restored by 2-mercaptoethanol or dithiothreitol. The content of pyrrole-2-carboxylate oxygenase was about 6% of the soluble protein as determined by antibodies raised against the enzyme. No cross reacting material was present in other bacteria also able to degrade pyrrole-2-carboxylate. A low amount of the enzyme was present in uninduced cells of Arthrobacter strain Py1, although the enzymatic activity was below the detection limit. The N-terminal amino acid sequence of the enzyme did not contain the consensus sequence GXGXXG found to be present close to the N-terminus of many flavin-dependent monoxygenases sequenced so far.

Construction of a new host-vector system in Arthrobacter sp. and cloning of the lipase gene.

Abstract: Arthrobacter sp. strain MIS38 was transformed with a shuttle vector containing the kanamycin resistant genekan (derived from Tn5) by an electroporation method. This shuttle vector is fromBrevibacterium lactofermentum andEscherichia coli, pULRS8: - The following optimal condition of electroporation was determined. A square wave pulse of 1 kV/cm electric field strength for 0.5 ms duration yielded 3 × 105 transformants/,μg plasmid DNA. The number of transformants increased with the amount of DNA over the range 0.01-5 μg. This host-vector system was then used successfully to clone and express a lipase gene fromArthrobacter sp. strain MIS38 into bothArthrobacter sp. MIS38 and E. coli JM109.

Characterization of an endoserine protease secreted by Arthrobacter aureus.

Abstract: A 22-kDa endoserine protease secreted by an Arthrobacter aureus strain was identified. The optimal temperature for this protease was 70 degrees C. Protease production was maximal at the end of the exponential growth phase, and the protease was induced by amino acids and peptides and repressed by carbon sources.

Production process of L-amino acids with bacteria

Abstract: A production process of optically active amino acids comprising causing a microorganism belonging to Rhodococcus, Mycobacterium, Arthrobacter, Nocardiopsis or Bacillus sp. and having nitrile-hydrolyzing activity to act on a nitrile or derivative thereof.

Regulation by ammonium and glucose of Arthrobacter fluorescens alanine dehydrogenase

Abstract: Alanine dehydrogenase in Arthrobacter fluorescens exhibited an allosteric behaviour and two Km values for ammonium were estimated. In batch cultures at different ammonium concentrations and in continuous culture following an NH4+ pulse, the level of ADH activity seems to be regulated by the ammonium concentration, high activities being observed when extracellular ammonium was in excess. The response to the growth rate of an ammonium-limited chemostat culture of A. fluorescens seems to indicate that alanine dehydrogenase and glutamine synthetase activities were inversely related. High activities of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase have been found in crude extract of ammonium-limited cultures. From the results obtained in batch cultures grown at different glucose concentrations and in carbon-limited chemostat culture it appeared that the limitation by glucose influenced alanine dehydrogenase activity negatively. No glutamate dehydrogenase activity and no glutamate synthase activity could be detected with either NADH or NADPH as coenzymes.

Production of hydrolase for cyclohexanecarboxylic acid phenyl ester

Abstract: PURPOSE:To efficiently obtain a hydrolase for phenyl cyclohexanecarboxylate useful for production, etc., of medicines and liquid crystal compounds by culturing a microorganism belonging to the genus Alcaligenes, etc., and having ability capable of producing a hydrolase for phenyl cyclohexanecarboxylate and then harvesting a product from the cultured mixture. CONSTITUTION:A microorganism having ability capable of producing a hydrolase for phenyl cyclohexanecarboxylate and belonging to the genus Alcaligenes, Arthrobacter, Achromobacter, Agrobacterium, Aeromonas, Bacillus, Comamonas, Corynebacterium, Enterobacter, Escherichia, Micrococcus or Pseudomonas is cultured in a medium at 30 deg.C for 24hr. The resultant cultured mixture is centrifuged to harvest a bacterial cell and the bacterial cell is suspended in a buffer solution and broken by a cell blender and then centrifuged to harvest a supernatant and the supernatant is purified by an ion exchange column chromatography and gel permeation to provide the objective enzyme useful for production, etc., of cetraxate important as a medicine and liquid crystal ester compounds.

Mossbauer data on the effect of NAD.H on the state of iron in bacteria

Abstract: The state of Fe of bacterial cultures of different systematic positions (Bacillus megaterium, Bacillus polymyxa, Pseudomonas putida, Pseudomonas fluorescens, Alcaligenes faecalis, Arthrobacter siderocapsulatus) grown on the medium containing Fe(III) citrate (up to 100 mg/l) with additional or without NAD.H was studied. The samples were in damp air-dry, second moistened, dried at 383 K states. Spectra have been obtained at 290 K and 100-200 K. The studied microorganisms have two types of atoms of Fe(III) which dissociated into protoplasm or into cell slug at damp state. All studied microorganisms except Arthrobacter siderocapsulatus do not reduce iron at all variants of experiments. Arthrobacter siderocapsulatus reduces about 50% of cell iron only the presence of NAD.H creating two types of Fe(II) complexes firmly connected with cell.

Method of ciliated protozoans cultivation

Abstract: FIELD: microbiology SUBSTANCE: nutrient medium for cultivation of protozoans has additionally ethyleneglycol and diethanolamine at concentration 300-600 mg/l Used microorganisms are Arthrobacter and Pseudomonas EFFECT: simplified method and providing for growing of pure culture Colpoda 2 tbl