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Effect of freezing and thawing on survival of three bacterial isolates from an arctic soil.

Three isolates, a Pseudomonas sp., Bacillus sp., and Arthrobacter sp., which had been isolated from a meadow soil at Devon Island, Canada, were subjected to freezing and thawing at low rates under various conditions. When cells were frozen in sand or soil, survival was dependent on moisture level, storage time, and thaw rate. Pseudomonas M216 was most susceptible to freeze-thaw damage under these conditions. Arthrobacter M51 was the most resistant of the three isolates when frozen in sand or soil and when frozen at a high rate after growth at varing rates at 5 and 15 degrees C in carbon-or nitrogen-limited media. Pseudomonas M216 was more sensitive to freeze-thaw damage when NaCl was present in the freezing menstruum, even at low freezing rates. Survival of cells frozen in growth medium, water, saline, and soil extract was not affected by the freezing rate when it was less than 1 degrees C min-1. Soil extract did not protect cells from freeze-thaw damage any more than water and for Arthrobacter M51 survival was decreased when it was frozen in soil extract.

Arctic Regions↗

Microbial production of optically active beta-phenylalanine through stereoselective degradation of racemic beta-phenylalanine.

The ability to produce (R)- or (S)-beta-phenylalanine from racemic beta-phenylalanine through stereoselective degradation was screened for. Variovorax sp. JH2 and Arthrobacter sp. the faculty of Agriculture, Kyoto University (AKU) 638 were found to be potential catalysts for (R)- and (S)-beta-phenylalanine production respectively. On 192 h cultivation of Variovorax sp. in medium containing 1.0% (w/v) racemic beta-phenylalanine, 0.46% (w/v) (R)-beta-phenylalanine with an enantiomeric purity of 99% e.e. was obtained. The initial step of the (S)-isomer degradation was stereoselective transamination. On 312 h cultivation of Arthrobacter sp. in medium containing 1.0% (w/v) racemic beta-phenylalanine, 0.51% (w/v) (R)-beta-phenylalanine with an enantiomeric purity of 90% e.e. was obtained. The initial step of the (R)-isomer degradation was supposed to be oxidative deamination. Resting cell reaction with vigorous shaking, with cells of Arthrobacter sp. as the catalyst, resulted in production of 0.49% (w/v) of (S)-beta-phenylalanine with an enantiomeric purity of 99% e.e. from 1.0% (w/v) racemic beta-phenylalanine in 45 h.

Arthrobacter↗

[Chemotaxonomic markers of several coryneform bacteria and the "Rhodochrous" group].

Chemotaxonomic characters (the monosaccharide composition and diaminopimelic acid (DAP) of cell hydrolysates, the type of lipid LCN-A) were studied with bacteria of the "rhodochrous" complex and the Arthrobacter genus isolated from natural substrates as well as with collection strains of the genera Arthrobacter, Brevibacterium and Corynebacterium. If arabinose, galactose and meso-DAP were present in cell hydrolysates of these bacteria, they always contained lipid LCN-A. Bacteria of the "rhodochrous" complex can be differentiated from Corynebacterium sensu stricto by location of lipid LCN-A spots on chromatograms, and from the genera Brevibacterium (B. linens) and Arthrobacter, by the presence of arabinose, meso-DAP and lipid LCN-A in the cells. The representatives of two latter genera do not contain arabinose and lipid LCN-A in their cells.

Actinomycetales↗

[Spectrophotometric characteristics of the coccoid forms of actinomycetes].

IR spectra of thw whole cells of the coccoid forms (Mycococcus and Micrococcus) isolated from lithophilous lichen were compared with IR spectra of the collection cultures of Micrococcus and Arthrobacter. Generic spectral characteristics of Mycococcus and Micrococcus are presented. Spectral heterogeneity within the genus Arthrobacter complicates the diagnosis. The cultures of the Mycococcus genus were divided into three groups according to their spectral characteristics. Spectral scans of the studied coccoid forms differ from the scans of the mycelial actinomycetes, and their intensities within the range of 900-1200 cm-1 (lipids) decrease in the series Mycococcus, Arthrobacter, Micrococcus.

Arthrobacter↗

Effect of dicumarol on the growth of some soil microorganisms.

The effect of dicumarol on growth of selected soil bacteria: Azotobacter chroococcum, Arthrobacter globiformis, A. citreus and Bacillus megaterium was studied. The following minimum concentrations were inhibitory in vitro: Arthrobacter citreus--20 mug/ml., Bacillus megaterium--40 mug/ml., Azotobacter chroococcum--40 mug/ml. Arthrobacter globiformis--70 mug/ml. Cells of all microorganisms studied grown in the presence of dicumarol developed aberrant morphological forms.

Arthrobacter↗

Isolation and partial characterization of yeast mannan hydrolysing enzymes from bacterial isolates.

A range of aerobic, mesophilic bacterial strains capable of producing extracellular alpha-mannanase and alpha-mannosidase enzymes were isolated from various natural habitats using yeast cell wall material as the selective medium. Five of them were capable of producing extracellular alpha-mannosidase and alpha-mannanase on yeast mannan as the sole carbon substrate, and they were tentatively identified to the genus level as Arthrobacter, Streptomyces, Pseudomonas, Bacillus and Acinetobacter. Among these strains, Arthrobacter M-02 showed the highest biosynthetic activity of the enzymes. The crude enzyme preparations from the strains were active at pH 4 to 9, reaching a maximum activity between 5.5 and 6.8. The crude Arthrobacter M-02 alpha-mannosidase was more thermostable than that of the other strains, but the alpha-mannanase of the strain was thermolabile.

Acinetobacter↗

Whole cell-enzyme hybrid amperometric biosensor for direct determination of organophosphorous nerve agents with p-nitrophenyl substituent.

In this paper, we reported the construction of a hybrid biosensor for direct, highly selective, sensitive, and rapid quantitative determination of organophosphate pesticides with p-nitrophenyl substituent using purified organophosphorus hydrolase (OPH) for the initial hydrolysis and Arthrobacter sp. JS443 for subsequent p-nitrophenol oxidation. The biocatalytic layer was prepared by co-immobilizing Arthrobacter sp. JS443 and OPH on a carbon paste electrode. OPH catalyzed the hydrolysis of organophosphorus pesticides with p-nitrophenyl substituent such as paraoxon and methyl parathion to release p-nitrophenol that was oxidized by the enzymatic machinery of Arthrobacter sp. JS443 to carbon dioxide through electroactive intermediates 4-nitrocatechol and 1,2,4-benzenetriol. The oxidization current of the intermediates was measured and correlated to the concentration of organophosphates. The best sensitivity and response time were obtained using a sensor constructed with 0.06 mg dry weight of cell and 965 IU of OPH operating at 400 mV applied potential (vs. Ag/AgCl reference) in 50 mM citrate-phosphate pH 7.5 buffer at room temperature. Using these conditions, the biosensor measured as low as 2.8 ppb (10 nM) of paraoxon and 5.3 ppb (20 nM) of methyl parathion without interference from phenolic compounds, carbamate pesticides, triazine herbicides, and organophosphate pesticides that do not have the p-nitrophenyl substituent. The biosensor had excellent operational life-time stability with no decrease in response for more than 40 repeated uses over a 12-h period when stored at room temperature, while its storage life was approximately 2 days when stored in the operating buffer at 4 degrees C.

Actinobacteria↗

Isoprenoid quinones in the classification of coryneform and related bacteria.

Menaquinones were the only isoprenoid quinones found in 85 of the 95 coryneform bacteria examined. Dihydromenaquinones having nine isoprene units were the main components isolated from Corynebacterium bovis, from other glutamic acid-producing strains, and from Arthrobacter globiformis and related species. Dihydromenaquinones with eight isoprene units were found in Brevibacterium linens, the remaining Corynebacterium species and strains probably belonging to the genus Rhodococcus. Tetrahydromenaquinones with eight isoprene units were found in Arthrobacter simplex and Arthrobacter tumescens, and with nine isoprene units in Cellulomonas and Oerskovia. Kurthia and Curtobacterium were characterized by menaquinones with seven and nine isoprene units, respectively, and Microbacterium lacticum and Corynebacterium aquaticum had comparable amounts of menaquinones with 10 and 11 isoprene units. Strains received as Brevibacterium leucinophagum, Corynebacterium autotrophicum, Corynebacterium nephridii, Mycobacterium flavum, Mycoplana rubra and Protaminobacter ruber contained uniquinones as their sole isoprenoid quinones. The isoprenoid quinone data correlate well with major trends in coryneform taxonomy and are of value in the classification of coryneform and related bacteria.

Actinomycetales↗

Phylogenetic characterization of bacteria in the subsurface microbial culture collection.

The Subsurface Microbial Culture Collection (SMCC) was established by the U.S. Dept. of Energy (DOE) and contains nearly 10,000 strains of microorganisms (mostly bacteria) isolated from terrestrial subsurface environments. Selected groups of bacterial isolates from three sample sites situated above geochemically and hydrologically different subsurface environments have been characterized by phylogenetic analysis of 16S ribosomal RNA (rRNA) gene nucleotide sequences. Among these isolates were members of six major phylogenetic groups of bacteria: the high-G+C and low-G+C Gram-positive bacteria; the alpha-, beta-, and gamma-subdivisions of the Proteobacteria; and the Flexibacter/Cytophaga/Bacteroides group. A small number of the SMCC strains may be members of new bacterial genera, but most of them could be placed with reasonable confidence into more than 35 previously described genera. The majority of the Gram-positive isolates were species of Arthrobacter, Bacillus, or Streptococcus, whereas Acinetobacter, Comamonas, Pseudomonas, Sphingomonas, and Variovorax were among the most frequently encountered Gram-negative genera. A high proportion of the strains were placed in fewer than 10 genera, implying that there is substantial duplication within the SMCC at the genus level. When groups of isolates assigned to Acinetobacter, Arthrobacter, or Sphingomonas were analyzed in more detail, however, it was found that each group consisted of subgroups of strains that probably differed at the species level. Restriction endonuclease analysis (applied to the strains from one sample site) indicated that additional diversity was present at the strain level. Most of the SMCC isolates assigned to some genera (e.g., Acinetobacter) were very closely related to previously described species in those genera, but most of the isolates assigned to other genera (e.g., Arthrobacter and Sphingomonas) appeared (or were shown) to be new species, thereby indicating that a reasonable amount of novelty is present within the SMCC at the species level.

Bacteria↗

Use of the mushroom tissue block rapid pitting test to detect brown blotch pathogens.

Isolates of an Arthrobacter species known to produce a positive host pathogenicity test were evaluated by the mushroom tissue block rapid pitting test. All 11 isolates of the Arthrobacter species yielded a positive test response. The time required for a positive test was the same for Pseudomonas tolaasi and the Arthrobacter species.

Journal Article↗

Survival and phospholipid Fatty Acid profiles of surface and subsurface bacteria in natural sediment microcosms.

Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P. fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles.

Journal Article↗

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

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.

Bacteria↗

[Cadaverine is an intermediate in the biosynthesis of arthrobactin and ferrioxamine E (author's transl)].

Cadaverin was more readily incorporated than lysine into arthrobactin from Arthrobacter pascens and into ferrioxamin E from Streptomyces glaucescens. From a racemic mixture only the L-isomer of lysine is incorporated. The L-lysine decarboxylase activity was measured in vivo and in vitro. The enzyme from Arthrobacter pascens is not inducable by lysine and completely repressed by 5.10(-6) M Fe3+. In Klebsiella pneumoniae, the producer of aerobactin, only a very low activity of L-lysine decarboxylase was detected.

Arthrobacter↗

Hydroxylamine oxidation in heterotrophic nitrate-reducing soil bacteria and purification of a hydroxylamine-cytochrome c oxidoreductase from a Pseudomonas species.

Hydroxylamine oxidation was measured in four recently isolated heterotrophic nitrate-reducing bacteria belonging to the genera Pseudomonas, Moraxella, Arthrobacter and Aeromonas. A hydroxylamine-cytochrome c oxidoreductase activity was detected in periplasmic fractions of the Pseudomonas and Aeromonas spp. and in total soluble fractions of the Arthrobacter sp. A monomeric 19-kDa non-haem iron hydroxylamine-cytochrome c oxidoreductase was purified from the Pseudomonas species and shown to be similar to hydroxylamine-cytochrome c oxidoreductase of Paracoccus denitrificans.

Aeromonas↗

Microbial production of optically active beta-phenylalanine ethyl ester through stereoselective hydrolysis of racemic beta-phenylalanine ethyl ester.

The ability to produce (R)- or (S)-beta-phenylalanine ethyl ester (3-amino-3-phenylpropionic acid ethyl ester, BPAE) from racemic BPAE through stereoselective hydrolysis was screened for in BPAE-assimilating microorganisms. Sphingobacterium sp. 238C5 and Arthrobacter sp. 219D2 were found to be potential catalysts for (R)- and (S)-BPAE production, respectively. On a 24-h reaction, with 2.5% (w/v) racemic BPAE (130 mM) as the substrate and wet cells of Sphingobacterium sp. 238C5 as the catalyst, 1.15% (w/v) (R)-BPAE (60 mM) with enantiomeric purity of 99% e.e. was obtained, the molar yield as to racemic BPAE being 46%. On a 48-h reaction, with 2.5% (w/v) racemic BPAE (130 mM) as the substrate and wet cells of Arthrobacter sp. 219D2 as the catalyst, 0.87% (w/v) (S)-BPAE (45 mM) with enantiomeric purity of 99% e.e. was obtained, the molar yield as to racemic BPAE being 35%. The enzyme stereoselectively hydrolyzing (S)-BPAE was purified to homogeneity from the cell-free extract of Sphingobacterium sp. 238C5. The enzyme was a monomeric protein with a molecular mass of about 42,000. The enzyme catalyzed hydrolysis of beta-phenylalanine esters, while the common aliphatic and aromatic carboxylate esters were not catalyzed.

Arthrobacter↗

Rhizobacteria and their potential to control Fusarium verticillioides: effect of maize bacterisation and inoculum density.

Fusarium verticillioides is the most important seed transmitted pathogen that infects maize. It produces fumonisins, toxins that have potential toxicity for humans and animals. Control of F. verticillioides colonisation and systemic contamination of maize has become a priority area in food safety research. The aims of this research were (1) to characterise the maize endorhizosphere and rhizoplane inhabitant bacteria and Fusarium spp., (2) to select bacterial strains with impact on F. verticillioides growth and fumonisin B1 production in vitro, (3) to examine the effects of bacterial inoculum levels on F. verticillioides root colonisation under greenhouse conditions. Arthrobacter spp. and Azotobacter spp. were the predominant genera isolated from maize endorhizosphere and rhizoplane at the first sampling period, whilst F. verticillioides strains showed the greatest counts at the same isolation period. All F. verticillioides strains were able to produce fumonisin B1 in maize cultures. Arthrobacter globiformis RC5 and Azotobacter armeniacus RC2, used alone or in a mix, demonstrated important effects on F. verticillioides growth and fumonisin B1 suppression in vitro. Only Azotobacter armeniacus RC2 significantly reduced the F. verticillioides root colonisation at 10(6) and 10(7) CFU g(-1) levels under greenhouse conditions.

Antibiosis↗

The interaction of substrate-related ketals with bacterial and viral neuraminidases.

Arthrobacter sialophilus neuraminidase catalyzes the hydration of 5-acetamido-2,6-anhydro-3,5-dideoxy-D-glycero-D-galacto-non-2-enonic acid (2,3-dehydro-AcNeu) with Km and kcat values of 8.9 X 10(-4) M and 6.40 X 10(-4) s-1, respectively. The methyl ester of 2,3-dehydro-AcNeu as well as 2,3-dehydro-4-epi-AcNeu are also hydrated by the enzyme. The product resulting from the enzymatic hydration of 2,3-dehydro-AcNeu is N-acetylneuraminic acid. A series of derivatives of 2,3-dehydro-AcNeu (K1, 1.60 X 10(-6) M) including 2,3-dehydro-4-epi-AcNeu (2.10 X 10(-4) M) and 2,3-dehydro-4-keto-AcNeu (K1 = 6.10 X 10(-5) M) were each competitive inhibitors of the enzyme. The methyl esters of these ketal derivatives were also competitive enzyme inhibitors. Dissociation constants for these ketals were determined independently by fluorescence enzyme titrations which gave values similar to those found kinetically. These six relatives of 2,3-dehydro-AcNeu were also competitive inhibitors for the influenza viral neuraminidases. For the viral neuraminidases, the dissociation constant for 2,3-dehydro-AcNeu and its methyl ester were 2.40 X 10(-6) and 1.17 X 10(-3) M, respectively. The interpretation placed upon the K1 values determined for these ketals against the Arthrobacter versus influenza neuraminidases is that the bacterial enzyme has a more flexible glycone binding site.

Arthrobacter↗

An examination of proton translocation and energy conservation during heterotrophic nitrification.

Whether selected heterotrophic nitrifiers, as do the autotrophs, conserve energy during the oxidation of their nitrogenous substrates was studied. The examination of proton translocation of four different bacterial nitrifiers capable of pyruvic oxime [(PO), CH3-C(NOH)-COOH] nitrification and by an NH4+ oxidizing Arthrobacter sp. was initiated. Three of the PO nitrifying bacteria, all pseudomonads, oxidize hydroxylamine (NH2OH) at a greater rate than PO and yielded only stoichiometric protons when NH2OH was the reductant. The fourth bacterium, Alcaligenes faecalis ATCC 8750, an adept PO oxidizer, does not appreciably oxidize NH2OH. The bacterium displayed----H+NH2OH ratios far less than if NH2OH was stoichiometrically converted to nitrite. When given NH4+, the Arthrobacter sp. yielded proton translocation patterns which were inconsistent with the metabolic data collected concerning NH4+ oxidation. Thus no data was collected which supported energy conservation via proton translocation by these heterotrophic nitrifiers.

Alcaligenes↗