Showing papers on "Arthrobacter published in 1992"

Cloning and sequence analysis of genes for dehalogenation of 4-chlorobenzoate from Arthrobacter sp. strain SU.

Abstract: Strains of Arthrobacter catalyze a hydrolytic dehalogenation of 4-chlorobenzoate (4-CBA) to p-hydroxybenzoate. The reaction requires ATP and coenzyme A (CoA), indicating activation of the substrate via a thioester, like that reported for Pseudomonas sp. strain CBS3 (J. D. Scholten, K.-H. Chang, P. C. Babbit, H. Charest, M. Sylvestre, and D. Dunaway-Mariano, Science 253:182-185, 1991). The dehalogenase genes of Arthrobacter sp. strain SU were cloned and expressed in Escherichia coli. Analyses of deletions indicate that dehalogenation depends on three open reading frames (ORFs) which are organized in an operon. There is extensive sequence homology to corresponding gene products in Pseudomonas sp. strain CBS3, suggesting that ORF1 and ORF2 encode a 4-CBA-CoA-ligase and a 4-CBA-CoA dehalogenase, respectively. ORF3 possibly represents a thioesterase, although no homology to the enzyme from Pseudomonas sp. strain CBS3 exists.

Indole-3-acetic acid (IAA) production by Arthrobacter species isolated from Azolla

Abstract: SUMMARY: Arthrobacter species, isolated from the leaf cavities and the microsporocarps of the aquatic fern species Azolla pinnata and Azolla filiculoides, produced indole-3-acetic acid (IAA) in culture when the precursor tryptophan was added to the medium. No IAA production was detected in the absence of tryptophan. Maximum IAA formation was obtained in the first 2 d of incubation. Part of the tryptophan was transformed to Nα-acetyl-L-tryptophan.

Mechanism ofD-fructose isomerization by Arthrobacter D-xylose isomerase

Abstract: The mechanism of D-fructose isomerization by Arthrobacter D-xylose isomerase suggested from X-ray-crystallographic studies was tested by detailed kinetic analysis of the enzyme with various metal ions at different pH values and temperatures. At D-fructose concentrations used in commercial processes Mg2+ is the best activator with an apparent dissociation constant of 63 microM; Co2+ and Mn2+ bind more strongly (apparent Kd 20 microM and 10 microM respectively) but give less activity (45% and 8% respectively). Ca2+ is a strict competitive inhibitor versus Mg2+ (Ki 3 microM) or Co2+ (Ki 105 microM). The kinetics show a compulsory order of binding; Co2+ binds first to Site 2 and then to Site 1; then D-fructose binds at Site 1. At normal concentrations Mg2+ binds at Site 1, then D-fructose and then Mg2+ at Site 2. At very high Mg2+ concentrations (greater than 10 mM) the order is Mg2+ at Site 1, Mg2+ at Site 2, then D-fructose. The turnover rate (kcat.) is controlled by ionization of a residue with apparent pKa at 30 degrees C of 6.0 +/- 0.07 (Mg2+) or 5.3 +/- 0.08 (Co2+) and delta H = 23.5 kJ/mol. This appears to be His-219, which is co-ordinated to M[2]; protonation destroys isomerization by displacing M[2]; Co2+ binds more strongly at Site 2 than Mg2+, so competes more strongly against H+. The inhibition constant (Ki) for the two competitive inhibitors 5-thio-alpha-D-glucopyranose and D-sorbitol is invariant with pH, but Km(app.) in the Mg[1]-enzyme is controlled by ionization of a group with pKa 6.8 +/- 0.07 and delta H = 27 kJ/mol, which appears to be His-53. This shows that Km(app.) is a complex constant that includes the rate of the ring-opening step catalysed by His-53, which explains the pH-dependence. In the Mg[1]Mg[2]-enzyme or Co[1]Co[2]-enzyme, the pKa is lower (6.2 +/- 0.1 or 5.6 +/- 0.08) because of the extra adjacent cation. Hence the results fit the previously proposed pathway, but show that the mechanisms differ for Mg2+ and Co2+ and that the rate-limiting step is isomerization and not ring-opening as previously postulated.

General properties of extracellular bacterial inulinase

Abstract: The extracellular inulinase system of a strain of Arthrobacter sp. consists of a β-fructofuranosidase active on inulin raffinose and sucrose with a relative rate inulin/sucrose (I/S) of 0.2. Crude enzyme preparations were obtained by fractionation of the liquid culture at stationary phase of growth with ammonium sulphate. Purification was carried out by DEAE cellulose chromatography and ultrogel ACA 34. Only one protein band was observed by electrophoresis. The enzyme was stable at high temperatures and was active at neutral or slightly alkali pH. Fructose is liberated as the sole reaction product of inulin hydrolysis, suggesting that the enzyme was an exoinulinase. The Michaelis constant (calculated at 40°C and pH 6) was 0.25 × 10-2 mol/l for the inulin and 0.12 × 10-2 mol/l for sucrose. The enzyme was suitable for fructose production from root extracts of plants rich in polyfructosans or sucrose.

Myceloid cell formation in Arthrobacter globiformis during osmotic stress

Abstract: C.E. DEUTCH AND G.S. PERERA. 1992. Arthrobacter globiformis was grown in a semi-defined liquid medium containing added solutes to determine the effects of osmotic stress on its reproduction and cell morphology. There was a progressive reduction in the specific growth rate during exponential phase as the concentration of NaCl was increased, although the final yields of the cultures during stationary phase were not affected. Clusters of branching myceloid cells rather than the typical bacillary forms predominated during exponential phase. These myceloids did not undergo complete septation and persisted into stationary phase. Similar responses were observed with potassium sulphate as the exogenous solute but less dramatic morphological effects were found with added polyethylene glycol or sucrose. The myceloids formed in response to osmotic stress could not be disrupted mechanically but were more sensitive than normal cells to lysozyme, particularly during stationary phase. Addition of osmoprotective compounds such as proline, glutamate, glycine betaine, or trehalose to the growth medium did not significantly relieve the effects of osmotic stress on growth rate or morphology. A. simplex also formed myceloid cells during osmotic stress but A. crystallopoietes did not. These results indicate that arthrobacters exhibit characteristic responses to osmotic stress and suggest these bacteria may contain novel osmoprotective compounds.

Method of producing trehalose

Abstract: A method of producing trehalose, in which a microorganism belonging to the genus Brevibacterium , Corynebacterium , Microbacterium or Arthrobacter and having the ability of producing trehalose is cultured in a liquid medium containing sucrose or maltose as an essential carbon source and the trehalose produced and accumulated in the culture is collected therefrom. In accordance with the method of the present invention, trehalose is produced inexpensively and efficiently by industrial mass-production.

Metabolic blocks in the degradation of β‐sitosterol by a plasmid‐cured strain of Arthrobacter oxydans

Abstract: Plasmid-harbouring, sterol-decomposing organism Arthrobacter oxydans 317 was treated with sodium dodecylsulphate to obtain a plasmid-cured strain A. oxydans 317 A1 incapable of utilizing 4-androstene-3,17-dione (AD). The strain 317 Al was unable to degrade β-sitosterol side chain completely to form AD but could carry out partial degradation as shown by the accumulation of 3-oxochol-4-en-24-oic acid as a major metabolite and 27-norcholest-4-en-3,24-dione as a minor metabolite. The strain could form 1,4-androstadiene-3,17-dione (ADD) from 3-oxo-23,24-bisnorchol-1,4-dien-22-oic acid (BNC) to a limited extent. The existence of metabolic blocks in the conversion of 3-oxochol-4-en-24-oic acid to 3-oxo-23,24-bis-norchol-4-en-22-oic acid and further conversion to AD by the plasmid-cured strain 317 Al was suggested. Neither the formation of ADD from AD nor the conversion of AD and ADD to 9α-hydroxy derivatives leading to steroid ring opening could be done by the plasmid-cured strain but the 17β-reduction of AD and ADD and 1(2)-reduction of ADD were not affected by the absence of the plasmid. It was proposed that plasmid determines 1(2)-dehydrogenation and 9α-hydroxylation of steroid ring structure in this organism.

Siderophores and related outer membrane proteins produced by pseudomonads isolated from eels and freshwater

Abstract: A total of 46 environmental pseudomonads, together with six type strains, were examined for their siderophore-producing activity. All strains were able to grow under iron-limiting conditions, gave orange halos in the CAS agar assay, and produced hydroxamates, and some of them also produced phenolate-type compounds. Bioassays showed that all strains, except Pseudomonas aeruginosa, promoted growth of mutant strain Arthrobacter flavescens JG-9, deficient in hydroxamate production, and some of them promoted growth of Salmonella typhimurium enb-1, which requires enterobactin for growth. The presence of iron-regulated outer membrane proteins was observed, the molecular size of the main induced proteins ranged between 76 and 93 kDa.

Production of trehalose

Abstract: PURPOSE: To efficiently obtain trehalose at low cost in an industrial way. CONSTITUTION: Microorganisms belonging to the genera Brevibacterium, Corynebacterium, Microbacterium or Arthrobacter and having ability to produce trehalose are cultured in a liquid medium with sucrose or maltose as the main carbon source, and the trehalose built up in the culture solution is collected. COPYRIGHT: (C)1993,JPO&Japio

Lipids of Arthrobacter siderocapsulatus

Abstract: E.N. AMADI AND G. ALDERSON. 1992. The results of lipid studies confirm that Arthrobacter siderocapsulatus is not a member of the genus Arthrobacter. Further studies are required to determine the taxonomic status of these Gram-negative bacteria.

Enzyme formation by a yeast cell wall lytic Arthrobacter species: formation of amylase

Abstract: The kinetics of amylolytic enzyme formation by a yeast cell wall lytic Arthrobacter species were studied. Cultivation on autoclaved cells of baker's yeast showed that amylase formation was closely related to trehalose and glycogen dissimilation. Growth on yeast glycogen (0.5%) proceeded quite rapidly (μ = 0.31 h−1) with extensive amylase formation during exponential cell multiplication and a further low increase in activity during the stationary phase. Beside amylolytic activity [450 units (U) l−1] the formation of a relatively high level of α-glucosidase (90 U l−1) was detected, the latter almost exclusively bound to bacterial cells. Growth on 0.5% trehalose occurred at a reduced rate (μ = 0.22 h−1) with post-logarithmic enzyme synthesis in the stationary phase. Amylase activity attained a level of 1200 U l−1, whereas α-glucosidase was very low at 7.7 U l−1. Continuous culture experiments in the chemostat showed maximal volumetric productivity of amylase (105 U l−1 h−1) at a dilution rate of 0.15 h−1. Growth on various carbohydrates revealed low levels of amylolytic activity (<100 U l−1), which were increased by a α-1,4-glucans and oligosaccharides such as starch, dextrin, maltotriose and maltose. On 0.5% maltose, growth-associated enzyme synthesis (230 U l−1) was detected at a reduced growth rate (μ = 0.14 h−1). Amylolytic enzyme preparations from the culture fluid showed an unusual cleavage pattern; acting on starch, the polymer was almost completely hydrolysed to maltotriose and maltose in a molar ratio of 3:1.

Immunological demonstration of a unique 3,4-dihydroxyphenylacetate 2,3-dioxygenase in soil Arthrobacter strains.

Abstract: Many bacteria biosynthesize 3,4-dihydroxyphenylacetate 2,3-dioxygenases for growth on aromatic acids, but gram-negative organisms have been most extensively studied. A gram-positive strain containing 2,3-dioxygenase activity was identified as Arthrobacter strain Mn-1. The 2,3-dioxygenase from strain Mn-1 was purified to homogeneity by fast protein liquid chromatography with a Mono Q anion-exchange column. Rabbit polyclonal antidioxygenase antibodies were prepared. Ouchterlony double-diffusion and Western blotting (immunoblotting) protocols were used to probe the distribution of the Mn-1 dioxygenase antigen in soil bacteria. Fourteen 2,3-dioxygenase-containing Bacillus and Pseudomonas strains did not contain immunologically cross-reactive proteins. Six of eight Arthrobacter strains contained 2,3-dioxygenase activity, and all of them produced cross-reactive proteins. The data presented here suggest that a unique type of dioxygenase is geographically widespread but is taxonomically confined to Arthrobacter soil bacteria.

Biotransformation of zearalenone

Abstract: The conversion of Zearalenone by some strains of microorganisms was investigated. When the selective strains of Rhodotorula sp., Arthrobacter sp., Saccharomyces sp., and Candida sp. were incubated by shaking or standing at 28 degrees C for 72 h with an alcoholic solution of Zearalenone as the substrate at a concentration of 2-10 mg/ml ethanol (50-100 micrograms/ml medium), it was readily converted to give Zearalenols, consisting either mainly of the alpha-isomer (e.g. 96% in case of Rhodotorula sp. and 84% in case of Arthrobacter sp. as determined by HPLC) or beta-isomer (e.g. 91% and 92% in Saccharomyces sp. and Candida sp., respectively). The structure of the product was confirmed by 13C-NMR, MS and HPLC.

[Plasmids for biodegradation of 2,6-dimethylpyridine, 2,4-dimethylpyridine, and pyridine in strains of Arthrobacter].

Abstract: Arthrobacter crysallopoietes strain KM-4 degrading 2,6-dimethylpyridine and strain KM-4a degrading both 2,6-dimethylpyridine and pyridine, Arthrobacter sp KM-4b degrading 2,4-dimethylpyridine were isolated from soil Arthrobacter crystallopoietes KM-4 and Arthrobacter sp KM-4b contain 100 Md plasmids pBS320 and pBS323 Arthrobacter crystallopietes KM-4a harbours a 100 Md and 80 Md plasmids Plasmid curing and conjugation transfer results confirm that these plasmids are involved in degradation of 2,6-dimethylpyridine, 2,4-dimethylpyridine and pyridine A mutant with lost ability to degrade 2,6-dimethylpyridine was isolated during the growth of strain KM-4 rifR at 42 degrees C Electrophoretic analysis of the plasmid from temperature sensitive mutant revealed the deletion the size of 26 Md from pBS320 plasmid

Method of producing trehalose by microorganisms which can produce tremalose with sucrose or maltose as main carbon source

Abstract: A method of producing trehalose, in which a microorganism belonging to the genus Brevibacterium, Corynebacterium, Microbacterium or Arthrobacter and having the ability to produce trehalose is incubated in a liquid medium containing sucrose or maltose as an essential carbon source and the trehalose produced and accumulated in the culture is collected therefrom. Trehalose is produced inexpensively and efficiently by industrial mass-production.