Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
arthrobacter soli sp. nov., a novel bacterium isolated from wastewater reservoir sediment.a novel gram-positive bacterium, designated syb2t, was isolated from wastewater reservoir sediment, and a polyphasic taxonomic study was conducted based on its morphological, physiological, and biochemical features, as well as the analysis of its 16s rrna gene sequence. during the phylogenetic analysis of the strain syb2t, results of a 16s rrna gene sequence analysis placed this bacterium in the genus arthrobacter within the family micrococcaceae. syb2t and arthrobacter protophormiae atcc 19271t ...200818337691
thermodynamic analysis of denaturant-induced unfolding of hodc69s protein supports a three-state mechanism.thermodynamic stability parameters and the equilibrium unfolding mechanism of his 6hodc69s, a mutant of 1 h-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (hod) having a cys to ser exchange at position 69 and an n-terminal hexahistidine tag (his 6hodc69s), have been derived from isothermal unfolding studies using guanidine hydrochloride (gdnhcl) or urea as denaturants. the conformational changes were monitored by following changes in circular dichroism (cd), fluorescence, and dynamic light scattering ...200818549245
functional diversity and electron donor dependence of microbial populations capable of u(vi) reduction in radionuclide-contaminated subsurface sediments.in order to elucidate the potential mechanisms of u(vi) reduction for the optimization of bioremediation strategies, the structure-function relationships of microbial communities were investigated in microcosms of subsurface materials cocontaminated with radionuclides and nitrate. a polyphasic approach was used to assess the functional diversity of microbial populations likely to catalyze electron flow under conditions proposed for in situ uranium bioremediation. the addition of ethanol and gluc ...200818378664
chemostat selection of a bacterial community able to degrade s-triazinic compounds: continuous simazine biodegradation in a multi-stage packed bed biofilm reactor.using a successive transfer method on mineral salt medium containing simazine, a microbial community enriched with microorganisms able to grow on simazine was obtained. afterwards, using a continuous enrichment culture procedure, a bacterial community able to degrade simazine from an herbicide formulation was isolated from a chemostat. the continuous selector, fed with a mineral salt medium containing simazine and adjuvants present in the commercial herbicide formulation, was maintained in opera ...200818392868
catalytic mechanism of inulinase from arthrobacter sp. s37.detailed catalytic roles of the conserved glu323, asp460, and glu519 of arthrobacter sp. s37 inulinase (enia), a member of the glycoside hydrolase family 32, were investigated by site-directed mutagenesis and ph-dependence studies of the enzyme efficiency and homology modeling were carried out for enia and for d460e mutant. the enzyme efficiency (k(cat)/k(m)) of the e323a and e519a mutants was significantly lower than that of the wild-type due to a substantial decrease in k(cat), but not due to ...200818395004
[isolation of antibiotic resistance bacterial strains from east siberia permafrost sediments].a collection of bacterial antibiotic resistance strains isolated from arctic permafrost subsoil sediments of various age and genesis was created. the collection included approximately 100 strains of gram-positive (firmicutes, arthrobacter) and gram-negative bacteria (bacteroidetes, gamma-proteobacteria, and alpha-proteobacteria) resistant to aminoglycoside antibiotics (gentamycin, kanamycin, and streptomycin), chloramphenicol and tetracycline. antibiotic resistance spectra were shown to differ i ...200818409385
genetic analysis of phenylacetic acid catabolism in arthrobacter oxydans cect386.arthrobacter oxydans cect386 is a gram-positive bacterium able to use either phenylacetic acid or phenylacetaldehyde as the sole carbon and energy source for aerobic growth. genes responsible for the catabolism of these compounds have been located at two chromosomal regions and were organized in one isolated paan gene and two putative paa operons, one consisting of the paad, paaf, tetr and prot genes, and one consisting of the paag, paah, paai, paaj, paak and paab genes. the identity of the paaf ...200818437357
structure of 2,6-dihydroxypyridine 3-hydroxylase from a nicotine-degrading pathway.the enzyme 2,6-dihydroxypyridine-3-hydroxylase catalyzes the sixth step of the nicotine degradation pathway in arthrobacter nicotinovorans. the enzyme was produced in escherichia coli, purified and crystallized. the crystal structure was solved at 2.6 a resolution, revealing a significant structural relationship with the family of fad-dependent aromatic hydroxylases, but essentially no sequence homology. the structure was aligned with those of the established family members, showing that the fad ...200818440023
study of cadmium, zinc and lead biosorption by orange wastes using the subsequent addition method.the biosorption of several metals (cd2+, zn2+ and pb2+) by orange wastes has been investigated in binary systems. multicomponent sorption isotherms were obtained using an original procedure, similar to that proposed by pagnanelli et al. [pagnanelli, f., petrangeli, m.p., toro, l., trifoni, m., veglio, f., 2001a. biosorption of metal ions on arthrobacter sp.: biomass characterization and biosorption modelling. environ. sci. technol. 34, 2773-2778] for monoelement systems, known as subsequent addi ...200818440805
swapping metals in fe- and mn-dependent dioxygenases: evidence for oxygen activation without a change in metal redox state.biological o(2) activation often occurs after binding to a reduced metal [e.g., m(ii)] in an enzyme active site. subsequent m(ii)-to-o(2) electron transfer results in a reactive m(iii)-superoxo species. for the extradiol aromatic ring-cleaving dioxygenases, we have proposed a different model where an electron is transferred from substrate to o(2) via the m(ii) center to which they are both bound, thereby obviating the need for an integral change in metal redox state. this model is tested by usin ...200818492808
enantiomer-specific binding of ruthenium(ii) molecular wires by the amine oxidase of arthrobacter globiformis.the copper amine oxidase from arthrobacter globiformis (agao) is reversibly inhibited by molecular wires comprising a ru(ii) complex head group and an aromatic tail group joined by an alkane linker. the crystal structures of a series of ru(ii)-wire-agao complexes differing with respect to the length of the alkane linker have been determined. all wires lie in the agao active-site channel, with their aromatic tail group in contact with the trihydroxyphenylalanine quinone (tpq) cofactor of the enzy ...200818507382
[diversity of actinomycetes in wuling mountain].to isolate new actinomycetes for discovering compounds of pharmaceutical importance.200818837376
purification and characterization of cyclic maltosyl-(1-->6)-maltose hydrolase and alpha-glucosidase from an arthrobacter globiformis strain.cyclic maltosyl-maltose [cmm, cyclo-[-->6)-alpha-d-glcp-(1-->4)-alpha-d-glcp-(1-->6)-alpha-d-glcp-(1-->4)-alpha-d-glcp-(1-->]], a novel cyclic tetrasaccharide, has a unique structure. its four glucose residues are joined by alternate alpha-1,4 and alpha-1,6 linkages. cmm is synthesized from starch by the action of 6-alpha-maltosyltransferase from arthrobacter globiformis m6. recently, we determined the mechanism of extracellular synthesis of cmm, but the degrading pathway of the saccharide remai ...200818603794
phylogenetic analysis on the bacteria producing non-volatile fungistatic substances.this study characterized the soil bacteria producing non-volatile fungistatic substances. among the 2,100 colonies of soil bacteria randomly isolated from seven agricultural soil samples, 518 isolates (24.67% of total) showed fungistatic activity toward nematophagous fungi paecilomyces lilacinus and trichoderma viride by producing non-volatile substances. a phylogenetic analysis based on amplified ribosomal dna restriction analysis (ardra) and 16s rdna sequence placed the 518 bacteria in three g ...200818604493
further insight into the mechanism of stereoselective proton abstraction by bacterial copper amine oxidase.during the catalytic reaction of copper amine oxidase, one of the two prochiral hydrogen atoms at the c1 position of substrate amine is stereoselectively abstracted by a conserved asp residue serving as a general base. using stereospecifically deuterium-labeled enantiomers of 2-phenylethylamine, we previously showed that the pro-s alpha-proton is abstracted by the enzyme from arthrobacter globiformis (agao) [uchida, m., et al. (2003) biosci. biotechnol. biochem. 67, 2664-2667]. more recently, we ...200818627131
evidence for specificity of cultivable bacteria associated with arbuscular mycorrhizal fungal spores.bacteria associated with arbuscular mycorrhizal (am) fungal spores may play functional roles in interactions between am fungi, plant hosts and defence against plant pathogens. to study am fungal spore-associated bacteria (amb) with regard to diversity, source effects (am fungal species, plant host) and antagonistic properties, we isolated amb from surface-decontaminated spores of glomus intraradices and glomus mosseae extracted from field rhizospheres of festuca ovina and leucanthemum vulgare. a ...200818631178
structures of arthrobacter globiformis urate oxidase-ligand complexes.the enzyme urate oxidase catalyzes the conversion of uric acid to 5-hydroxyisourate, one of the steps in the ureide pathway. arthrobacter globiformis urate oxidase (aguox) was crystallized and structures of crystals soaked in the substrate uric acid, the inhibitor 8-azaxanthin and allantoin have been determined at 1.9-2.2 a resolution. the biological unit is a homotetramer and two homotetramers comprise the asymmetric crystallographic unit. each subunit contains two t-fold domains of betabetaalp ...200818645230
identities of arthrobacter spp. and arthrobacter-like bacteria encountered in human clinical specimens.after the initial description of arthrobacter spp. isolated from clinical specimens in the mid-1990s, very few further reports on arthrobacter spp. have appeared in the clinical microbiology literature. the aim of the present study was to elucidate the distribution of arthrobacter spp. and arthrobacter-like bacteria encountered in clinical specimens by studying 50 consecutively isolated or received strains of large-colony-forming, whiteish-grayish, non-cheese-like-smelling, nonfermentative gram- ...200818650355
[glucose isomerase activity in suspension of arthrobacter nicotianae cells and adsorption immobilization of the microorganisms on inorganic carriers].kinetics of monosaccharide isomerization has been studied in suspensions of intact, non-growing arthrobacter nicotianae cells. under the conditions of the study, glucose and fructose were isomerized at the same maximum rate of 700 micromol/min per 1 g dried cells, which increased with temperature (the dependence was linear at 60-80 degrees c). the proposed means of adsorption immobilization of a. nicotianae cells involve inorganic carriers differing in macrostructure, chemical nature, and surfac ...200818669262
different substrate specificities of two triazine hydrolases (trzns) from nocardioides species.nocardioides sp. strain mtd22 degraded atrazine, ametryn and atraton, as did arthrobacter aurescens strain tc1 and nocardioides sp. strain c190. these strains contain trzn, a gene coding for trzn, triazine hydrolase showing a broad substrate range. however, nocardioides sp. strain an3 degraded only atrazine despite containing trzn. these differences in s-triazine degradation are presumed to be due to differences in the amino acid sequences of trzns. consequently, 1371 nucleotides of the trzn cod ...200818671800
[catabolite repression of xylose isomerase synthesis in arthrobacter ureafaciens].the effect of a specific substrate as well as other carbon sources on the biosynthesis of xylose isomerase in the actinobacterium arthrobacter ureafaciens bim b-6 has been studied. it was established that xylose and its structural analogue xylite induced the production of the enzyme by bacterial cells. the inducing effect peaked at a concentration of specific substrates of 0.025% (as carbon) and then remained unchanged irrespective of the substrate amount. it has been shown that the synthesis of ...200818683646
corynebacterium ilicis is typified by icmp 2608 =icpb ci144, arthrobacter ilicis is typified by dsm 20138 =atcc 14264 =ncppb 1228 and the two are not homotypic synonyms, and clarification of the authorship of these two species. opinion 87.the judicial commission rules that the name corynebacterium ilicis mandel et al. 1961 is represented by the type strain icmp 2608 =icpb ci144 and is reported to be a plant-pathogenic species. arthrobacter ilicis is represented by the type strain dsm 20138 =atcc 14264 =ncppb 1228 and is not a homotypic synonym of corynebacterium ilicis mandel et al. 1961, and is reported not to be a plant pathogen. the authorship is to be cited as arthrobacter ilicis collins et al. 1982 and typification and the d ...200818676493
enhanced glycosylation with mutants of endohexosaminidase a (endo a). 200818677737
chromium (vi) reduction in activated sludge bacteria exposed to high chromium loading.a mixed-culture of bacteria collected from a wastewater treatment plant in brits, north-west province (south africa) biocatalytically reduced cr(vi) at much higher concentrations than previously observed in cultures isolated in north america. complete cr(vi) reduction in aerobic cultures was achieved at a high concentration of 200 mg/l after incubation for only 65 hours. under anaerobic conditions up to 150 mg, cr(vi)/l was completely removed after incubating for 130 to 155 hours, still higher t ...200818701792
the screening, characterization, and use of omega-laurolactam hydrolase: a new enzymatic synthesis of 12-aminolauric acid.several omega-laurolactam degrading microorganisms were isolated from soil samples. these strains were capable of growing in a medium containing omega-laurolactam as sole source of carbon and nitrogen. among them, five strains (t7, t31, u124, u224, and u238) were identified as cupriavidus sp. t7, acidovorax sp. t31, cupriavidus sp. u124, rhodococcus sp. u224, and sphingomonas sp. u238, respectively. the omega-laurolactam hydrolyzing enzyme from rhodococcus sp. u224 was purified to homogeneity, a ...200818685217
a refinery sludge deposition site: presence of nahh and alkj genes and crude oil biodegradation ability of bacterial isolates.204 bacterial isolates from four greek refinery sludge deposition sites were investigated for the presence of nahh and alkj genes encoding key enzymes of both aromatic and aliphatic hydrocarbon degradation pathways by pcr and dna hybridisation. members of pseudomonas, acinetobacter, bacillus, rhodococcus and arthrobacter play important role in bioremediation processes in sandy/loam soil contaminated with oil and nahh and alkj genes were present in the 73% of the isolates. consortia of bacterial ...200818688575
genome sequence of the fish pathogen renibacterium salmoninarum suggests reductive evolution away from an environmental arthrobacter ancestor.renibacterium salmoninarum is the causative agent of bacterial kidney disease and a significant threat to healthy and sustainable production of salmonid fish worldwide. this pathogen is difficult to culture in vitro, genetic manipulation is challenging, and current therapies and preventative strategies are only marginally effective in preventing disease. the complete genome of r. salmoninarum atcc 33209 was sequenced and shown to be a 3,155,250-bp circular chromosome that is predicted to contain ...200818723615
chromium (vi) reduction in activated sludge bacteria exposed to high chromium loading: brits culture (south africa).a mixed-culture of bacteria collected from a wastewater treatment plant in brits, north-west province (south africa) biocatalytically reduced cr(vi) at much higher concentrations than previously observed in cultures isolated in north america. cr(vi) reduction rate up to 8 times higher than the rate in previous cultures was achieved by the brits culture under aerobic conditions. near complete cr(vi) reduction was observed in batches under initial concentrations up to 200mg cr(vi)/l after incubati ...200818760438
multi-compound electrophoretic assays for tyramine oxidase with a uv area detector imaging multiple windows on a looped capillary.active pixel sensor uv area imaging and capacitively coupled contactless conductivity detection have been applied in an electrophoretically mediated microanalysis (emma) assay for substrate specificity of tyramine oxidase (arthrobacter sp.). use of the uv area imaging detector to monitor four windows in a capillary with three loops provided intrinsic self-referencing for all species and identified tyramine and 2-phenethylamine as the only reactive components in a multi-compound mixture. continuo ...200818589431
plasmon microscopy and imaging ellipsometry of artrobacter oxydans attached on polymer films.the attachment of artrobacter oxydans 1,388 on a newly synthesized biodegradable copolymer of poly-(hexanlactam)-co-block-poly-(delta-valerolactone) is investigated by optical, microscopic and biochemical methods. the potentials of surface plasmon microscopy and imaging ellipsometry for detecting microorganisms when al films are used to excite plasmons is assessed by comparing images obtained by these methods with dark field microscopy pictures. the experimental results demonstrate that in this ...200818565743
the shortest wire. 200818508968
analysis of enzyme-treated red blood cell surface and haemagglutination using a theory of soft-particle electrophoresis.enzymatic treatment of red blood cells is thought to reduce the cell zeta (zeta) potential, effectively decreasing the distance between cells to less than the length of an immunoglobulin g antibody binding site, and resulting in agglutination of cells. however, the zeta potential given by smoluchowski's formula is based on theories of the electrophoresis of hard colloidal particles. a theory has recently been developed for the electrophoresis of colloidal particles covered with polyelectrolytes, ...200818510578
manipulation of sinapine, choline and betaine accumulation in arabidopsis seed: towards improving the nutritional value of the meal and enhancing the seedling performance under environmental stresses in oilseed crops.sinapoylcholine (sinapine) is the most abundant antinutritional phenolic compound in cruciferous seeds. the quaternary ammonium compounds, choline, betaine and n,n-dimethylglycine, reside along a biosynthetic pathway linked to the synthesis of membrane phospholipids and neurotransmitters with various biological functions. in chicken, choline intake is required for optimal egg-laying performance and a choline supplement in diet is positively correlated with weight gains. a key step in sinapine bi ...200818515127
selection and identification of bacterial strains with methyl-tert-butyl ether, ethyl-tert-butyl ether, and tert-amyl methyl ether degrading capacities.nine bacterial strains isolated from two hydrocarbon-contaminated soils were selected because of their capacity for growth in culture media amended with 200 mg/l of one of the following gasoline oxygenates: methyl-tert-butyl ether (mtbe), ethyl-tert-butyl ether (etbe), and tert-amyl methyl ether (tame). these strains were identified by amplification of their 16s rrna gene, using fdl and rd1 primers, and were tested for their capacity to grow and biotransform these oxygenates in both mineral and ...200818522454
endohexosaminidase-catalysed glycosylation with oxazoline donors: fine tuning of catalytic efficiency and reversibility.a complete series of oxazoline di-, tri-, tetra-, and hexasaccharides, corresponding to the core sections of n-linked glycoprotein high mannose glycans, together with the corresponding oligosaccharides containing a central glucose unit, were synthesised and tested as glycosyl donors for glycosylation of a glcnacasn glycosyl amino acid catalysed by the endohexosaminidases m (endo m), a (endo a) and h (endo h). whilst endo h did not catalyse any glycosylation reactions, both endo m and endo a effi ...200818537207
on the role of histidine 351 in the reaction of alcohol oxidation catalyzed by choline oxidase.choline oxidase catalyzes the four-electron, flavin-linked oxidation of choline to glycine betaine with transient formation of an enzyme-bound aldehyde intermediate. the recent determination of the crystal structure of choline oxidase to a resolution of 1.86 a established the presence of two histidine residues in the active site, which may participate in catalysis. his466 was the subject of a previous study [ghanem, m., and gadda, g. (2005) biochemistry 44, 893-904]. in this study, his351 was re ...200818540638
high benzene concentrations can favour gram-positive bacteria in groundwaters from a contaminated aquifer.exposure to pollution exerts strong selective pressure on microbial communities, which may affect their potential to adapt to current or future environmental challenges. in this microcosm study, we used dna fingerprinting based on 16s rrna genes to document the impact of high concentrations of benzene on two bacterial communities from a benzene-contaminated aquifer situated below a petrochemical plant (siren, uk). the two groundwaters harboured distinct aerobic benzene-degrading communities able ...200818540887
isolation of alkali-tolerant benzene-degrading bacteria from a contaminated aquifer.to isolate benzene-degrading strains from neutral and alkaline groundwaters contaminated by benzene, toluene, ethylbenzene, xylenes (btex) from the siren aquifer, uk, and to test their effective ph range and ability to degrade tex.200818544140
protection against pathogen and salt stress by four plant growth-promoting rhizobacteria isolated from pinus sp. on arabidopsis thaliana.the ability of four plant growth-promoting rhizobacteria, isolated in a previous study, to induce systemic resistance on arabidopsis thaliana col 0 against biotic and abiotic stress was evaluated. all the bacteria enhanced protection against the foliar pathogen pseudomonas syringae dc3000 and increased plant tolerance to salt stress (nacl 60 mm). bacillus sp. strain l81 and arthrobacter oxidans strain bb1 performed best with a decrease in the disease index of 61.2 and 52.3%, respectively, and a ...200818944290
polydopamine-based permanent coating capillary electrochromatography for auxin determination.a novel, simple, and economical method for the preparation of open-tubular capillary column using polydopamine coating was reported for the first time. after the capillary was filled with dopamine solution for 20h, polydopamine was formed and deposited on the inner wall of capillary as permanent coating via the oxidation of dopamine by the oxygen dissolved in the solution. moreover, the electroosmotic flow of the coated capillaries was measured to be dependent on the repetitive coating times. th ...200818945432
[methodological aspects of assessing chitin utilization by soil microorganisms].a computational method for estimating specific activity of chitin decomposition by microorganisms is proposed. spectrophotometric and gas chromatographic methods have been used to determine the rates of chitinase production, biomass accumulation, and carbon dioxide emission by pure cultures of microorganisms grown on a chitin-containing medium. among dominants of the chitinolytic community of chernozem (trichoderma viride, stretomyces albolongus, alcaligenes, and arthrobacter), the highest chiti ...200818956744
metabolic cooperation of gordonia sp. strain mtcc 4818 and arthrobacter sp. strain wy in the utilization of butyl benzyl phthalate: effect of a novel co-culture in the degradation of a mixture of phthalates.degradation of butyl benzyl phthalate (bbp) by a co-culture of gordonia sp. strain mtcc 4818 and arthrobacter sp. strain wy was investigated. in the degradation of bbp by the co-culture, the limitations of the individual species in metabolizing bbp were overcome, leading to the development of a consortium capable of complete utilization of this ester. in the degradation of bbp by the co-culture, the presence of multiple esterases was demonstrated in both species by activity staining of non-denat ...200818957587
safety assessment of bacterial choline oxidase protein introduced in transgenic crops for tolerance against abiotic stress.genetically modified crops have resistance to abiotic stress by introduction of choline oxidase protein. in the present study, the safety of choline oxidase protein derived from arthrobacter globiformis was assessed for toxicity and allergenicity. the protein was stable at 90 degrees c for 1 h. toxicity studies of choline oxidase in mice showed no significant difference (p > 0.05) from control in terms of growth, body weight, food consumption, and blood biochemical indices. histology of gut tiss ...200819035641
kinetics and spectroscopic evidence that the cu(i)-semiquinone intermediate reduces molecular oxygen in the oxidative half-reaction of arthrobacter globiformis amine oxidase.the role of copper during the reoxidation of substrate-reduced amine oxidases by o(2) has not yet been definitively established. both outer-sphere and inner-sphere pathways for the reduction of o(2) to h(2)o(2) have been proposed. a key step in the inner-sphere mechanism is the reaction of o(2) directly with the cu(i) center of a cu(i)-semiquinone intermediate. to thoroughly examine this possibility, we have measured the spectral changes associated with single-turnover reoxidation by o(2) of sub ...200819053231
aerobic reduction of perchlorate by bacteria isolated in kerala, south india.possibility of perchlorate reduction by microbes raises hope for an eco-friendly mode of degradation of this toxic rocket fuel. this study reports 3 isolates (a1, a2 and a3) capable of molybdenum-independent degradation of perchlorate under aerobic conditions. the rate of degradation was the highest when perchlorate concentration was 17 mm, and then 3.2 mm, 4.7 mm and 4.1 mm of perchlorate was reduced by isolates a1, a2 and a3 (respectively) after 72 h at 28 degrees c under aerobic conditions. p ...200819029691
escravos light crude oil degrading potentials of axenic and mixed bacterial cultures.we assessed the relationship between growth profile and the extent of biodegradation of escravos light crude oil by axenic and mixed bacteria cultures in a shake flask. eleven petroleum-degrading bacteria were isolated by enrichment from oil-contaminated soils including, pseudomonas effusa, pseudomonas fluorescens, pseudomonas cruciviae, arthrobacter tumescens, pseudomonas species, pseudomonas tralucida, alcaligenes metacaligenes, micrococcus colpogenes, bacillus badius, nocardia paraffinae and ...200819029769
hydride transfer made easy in the reaction of alcohol oxidation catalyzed by flavin-dependent oxidases.choline oxidase (e.c. 1.1.3.17; choline-oxygen 1-oxidoreductase) catalyzes the two-step, four-electron oxidation of choline to glycine betaine with betaine aldehyde as enzyme-associated intermediate and molecular oxygen as final electron acceptor. biochemical, structural, and mechanistic studies on the wild-type and a number of mutant forms of choline oxidase from arthrobacter globiformis have recently been carried out, allowing for the delineation at molecular and atomic levels of the mechanism ...200819053234
substitution of an active site valine uncovers a kinetically slow equilibrium between competent and incompetent forms of choline oxidase.the enzymatic oxidation of choline to glycine betaine is of interest because organisms accumulate glycine betaine intracellularly in response to stress conditions. this is relevant for the genetic engineering of crops with economic interest that do not naturally possess efficient pathways for the synthesis of glycine betaine and for the potential development of drugs that target the glycine betaine biosynthetic pathway in human pathogens. to date, the best characterized choline-oxidizing enzyme ...200819053262
arthrobacter oxydans as a biocatalyst for purine deamination.deaminases are enzymes that catalyze the hydrolysis of amino groups of nucleosides or their bases. because these enzymes play important roles in nucleotide metabolism, they are relevant targets in anticancer and antibacterial therapies. mammalian deaminases are commercially available but the use of bacterial whole cells, especially as biocatalysts, is continuously growing because of their economical benefits. moreover, deaminases are useful for the preparative chemoenzymatic transformation of nu ...200819054089
arthrobacter defluvii sp. nov., 4-chlorophenol-degrading bacteria isolated from sewage.two 4-chlorophenol-degrading bacteria, strains 4c1-at and 4c1-b, were isolated from sewage flowing into geumho river near the daegu industrial complex in korea. cells of the strains were gram-positive and non-motile, displayed a rod-coccus life cycle and formed creamy white colonies on r2a agar or peptone-carbohydrate agar. the strains had chemotaxonomic markers that were consistent with classification in the genus arthrobacter, i.e. mk-9(h2) as the major menaquinone, iso- and anteiso-branched c ...200818676480
complexes of the copper-containing amine oxidase from arthrobacter globiformis with the inhibitors benzylhydrazine and tranylcypromine.complexes of arthrobacter globiformis amine oxidase (agao) with the inhibitors benzylhydrazine and tranylcypromine (an antidepressant drug) have been refined at 1.86 and 1.65 a resolution, respectively. both inhibitors form covalent adducts with the tpq cofactor. a tyrosine residue, proposed to act as a gate to the agao active site, is in its open conformation.200818607080
application of 16s rdna-dgge and plate culture to characterization of bacterial communities associated with the sawfly, acantholyda erythrocephala (hymenoptera, pamphiliidae).culture-based analysis was employed in parallel with pcr amplification of 16s rdna, coupled with denaturing gradient gel electrophoresis (dgge), to profile bacterial species associated with different developmental stages of the pine false webworm (pfw), acantholyda erythrocephala, a sawfly pest responsible for incidents of severe defoliation in commercially important tree plantations in north america. culture-based analysis revealed that pseudomonas spp. along with bacillus sphaericus and arthro ...200818769850
characterization and validation of a bioluminescent bioreporter for the direct detection of escherichia coli.a two-component bacteriophage-based bioluminescent reporter system was developed for the detection of escherichia coli in environmental samples. the bioreporter system consists of a luxi integrated lambda bacteriophage and a lux-based bioluminescent reporter cell that responds to the infection event through acyl-homoserine lactone (ahl) mediated quorum sensing and bioluminescent signal stimulation. this work addresses the ability of the bioreporter system to detect and quantify the target pathog ...200818593593
recovery of choline oxidase activity by in vitro recombination of individual segments.initial attempts to express a choline oxidase from arthrobacter pascens (apcho-syn) in escherichia coli starting from a synthetic gene only led to inactive protein. however, activity was regained by the systematic exchange of individual segments of the gene with segments from a choline oxidase-encoding gene from arthrobacter globiformis yielding a functional chimeric enzyme. next, a sequence alignment of the exchanged segment with other choline oxidases revealed a mutation in the apcho-syn, show ...200818704397
cold adaptation of enzyme reaction rates.a major issue for organisms living at extreme temperatures is to preserve both stability and activity of their enzymes. cold-adapted enzymes generally have a reduced thermal stability, to counteract freezing, and show a lower enthalpy and a more negative entropy of activation compared to mesophilic and thermophilic homologues. such a balance of thermodynamic activation parameters can make the reaction rate decrease more linearly, rather than exponentially, as the temperature is lowered, but the ...200818759500
enzymatic characterization of an amine oxidase from arthrobacter sp. used to measure phosphatidylethanolamine.ethanolamine oxidase was screened with the aim of using it to establish a novel enzymatic phosphatidylethanolamine assay. ethanolamine oxidase activity was detected in the crude extract of arthrobacter sp., and the enzyme was purified more than 15-fold in three steps with a 54% yield. sds-page revealed the presence of only one band, which migrated, with an apparent molecular mass of 70 kda. biochemical characterization of the enzyme showed phenylethylamine to be the preferred substrate, with the ...200818838796
[microbial community of freshwater sponges in lake baĭkal].the microbial community of baikal sponges has been studied in five species belonging to the genera swartschewskia, baicalospongia, and lubomirskia of the endemic family lubomirskiidae. the results show that the total numbers of bacteria and bacterioplankton production have an effect on the growth of l. baicalensis body. bacteria of the genera pseudomonas, bacillus, micrococcus, sarcina, flavobacterium, arthrobacter, and acinetobacter living in the sponges are representatives of the baikal bacter ...200818771026
coupled biocatalysts applied to the synthesis of nucleosides.biocatalytic procedures offer a good alternative to the chemical synthesis of nucleosides since biocatalyzed reactions are regio- and stereoselective and afford reduced by-products contents. among them, enzymatic transglycosylation between a pyrimidine nucleoside and a purine base catalyzed by nucleoside phosphorylases or microorganisms that contain them, has attracted considerable attention. in addition, the combination to other enzymatic steps has been explored. in this work we investigate the ...200818776493
genes involved in arsenic transformation and resistance associated with different levels of arsenic-contaminated soils.arsenic is known as a toxic metalloid, which primarily exists in inorganic form [as(iii) and as(v)] and can be transformed by microbial redox processes in the natural environment. as(iii) is much more toxic and mobile than as(v), hence microbial arsenic redox transformation has a major impact on arsenic toxicity and mobility which can greatly influence the human health. our main purpose was to investigate the distribution and diversity of microbial arsenite-resistant species in three different a ...200919128515
heterologous expression and characterization of choline oxidase from the soil bacterium arthrobacter nicotianae.in the course of a microbial screening of soil samples for new oxidases, different enrichment strategies were carried out. with choline as the only carbon source, a microorganism was isolated and identified as arthrobacter nicotianae. from this strain, a gene coding for a choline oxidase was isolated from chromosomal dna. this gene named coda was cloned in escherichia coli bl21-gold and the protein (an_coda) heterologously overexpressed as a soluble intracellular protein of 59.1 kda. basic bioch ...200918787818
plasmid as a measure of microbial degradation capacity for 2,4-dichlorophenoxyacetic acid.the purpose of this research was to pursuit the quantification of microbial degradation capacity for 2,4-dichlorophenoxyacetic acid (2,4-d) by detecting and quantifying a prominent 2,4-d degradation encoding plasmid. batch reactor acclimation, de-acclimation, and re-acclimation tests were conducted during which periods the courses of 2,4-d dissipation and plasmid evolution were quantitatively measured. pure cultures of bacterial strains were detected to give rise to a plasmid approximately the s ...200918930390
maturing dynamics of surface microflora in fontina pdo cheese studied by culture-dependent and -independent methods.to study the evolution of rind microbial communities in fontina pdo cheese.200919054234
the oligomeric assembly of the novel haem-degrading protein hbps is essential for interaction with its cognate two-component sensor kinase.hbps, a novel protein of previously unknown function from streptomyces reticuli, is up-regulated in response to haemin- and peroxide-based oxidative stress and interacts with the sens/senr two-component signal transduction system. in this study, we report the high-resolution crystal structures (2.2 and 1.6 a) of octomeric hbps crystallized in the presence and in the absence of haem and demonstrate that iron binds to surface-exposed lysine residues of an octomeric assembly. based on an analysis o ...200919244623
structural characterization and antithrombin activity of dermatan sulfate purified from marine clam scapharca inaequivalvis.glycosaminoglycans from the body of marine clam scapharca inaequivalvis were extracted at about 0.15- 0.18 mg/g of dry tissue, composed of dermatan sulfate (ds) (approx. 74%) and heparan sulfate (26%). after treatment with nitrous acid, ds was isolated for further complete structural characterization. agarose-gel electrophoresis in combination with various enzymes, chondroitin abc lyase, chondroitin b lyase, chondroitin acii lyase from arthrobacter aurescens, and chondroitin ac lyase from flavob ...200919056786
preliminary study of a microbeads based histamine detection for food analysis using thermostable recombinant histamine oxidase from arthrobacter crystallopoietes kait-b-007.we designed and prepared a micro biosensing system consisting of a flow through system with a sub-micro liter injection valve and a sub-micro liter volume bioreactor. an electrochemical detector was combined with the reactor for immediate detections. the volumes of the reactor and the sample loop for the injection were 850 nl and 320 nl, respectively. this paper described about the characteristics of the sensing system in the case of histamine detection for food analysis. histamine oxidase from ...200919064110
decomposition of cr(v)-diols to cr(iii) complexes by arthrobacter oxydans.we demonstrated previously that cr(vi) is readily reduced to oxocr(v)-diols at the surface of arthrobacter oxydans-a gram-positive aerobic bacteria isolated from columbia basalt rocks originated from a highly contaminated site in the usa. here, we report an electron spin resonance (esr) study of cr(iii) hydroxide formation from cr(v)-diols by this bacterial strain as cells were exposed to 35, 200, and 400 mg/l of cr(vi) under aerobic conditions as a batch culture and as lyophilized cells. the ti ...200919067030
arthrobacter sp. lipase immobilization for preparation of enantiopure masked beta-amino alcohols.recent reports on immobilization of lipase from arthrobacter sp. (abl, mtcc 5125; iiim isolate) on insoluble polymers have shown altered properties including stability and enantioselectivity. present work demonstrates a facile method for the preparation of enantiopure beta-amino alcohols by modulation of abl enzyme properties via immobilization on insoluble as well as soluble supports using entrapment/covalent binding techniques. efficacies of immobilized abl on insoluble supports prepared from ...200919081255
isolation and characterization of mesotrione-degrading bacillus sp. from soil.dissipation kinetics of mesotrione, a new triketone herbicide, sprayed on soil from limagne (puy-de-dôme, france) showed that the soil microflora were able to biotransform it. bacteria from this soil were cultured in mineral salt solution supplemented with mesotrione as sole source of carbon for the isolation of mesotrione-degrading bacteria. the bacterial community structure of the enrichment cultures was analyzed by temporal temperature gradient gel electrophoresis (ttge). the ttge fingerprint ...200919121884
crystallographic, spectroscopic, and computational analysis of a flavin c4a-oxygen adduct in choline oxidase.flavin c4a-oo(h) and c4a-oh adducts are critical intermediates proposed in many flavoenzyme reaction mechanisms, but they are rarely detected even by rapid transient kinetics methods. we observe a trapped flavin c4a-oh or c4a-oo(h) adduct by single-crystal spectroscopic methods and in the 1.86 a resolution x-ray crystal structure of choline oxidase. the microspectrophotometry results show that the adduct forms rapidly in situ at 100 k upon exposure to x-rays. density functional theory calculatio ...200919133805
high rate of n2 fixation by east siberian cryophilic soil bacteria as determined by measuring acetylene reduction in nitrogen-poor medium solidified with gellan gum.for evaluating n(2) fixation of diazotrophic bacteria, nitrogen-poor liquid media supplemented with at least 0.5% sugar and 0.2% agar are widely used for acetylene reduction assays. in such a soft gel medium, however, many n(2)-fixing soil bacteria generally show only trace acetylene reduction activity. here, we report that use of a n(2) fixation medium solidified with gellan gum instead of agar promoted growth of some gellan-preferring soil bacteria. in a soft gel medium solidified with 0.3% ge ...200919286791
construction, expression and characterization of fusion enzyme from arthrobacter oxydans dextranase and klebsiella pneumoniae amylase.an artificial fusion protein of arthrobacter oxydans dextranase and klebsiella pneumoniae alpha-amylase was constructed and expressed in escherichia coli. most of the expressed protein existed as an insoluble fraction, which was solubilized with urea. the purified fusion enzyme electrophoretically migrated as a single protein band; m = 137 kda, and exhibited activities of both dextranase (10.8 u mg(-1)) and amylase (7.1 u mg(-1)), which were lower than that of reference dextranase (13.3 u mg(-1) ...200919305953
genetic and phenotypic diversity of fenitrothion-degrading bacteria isolated from soils.twenty-seven fenitrothion-degrading bacteria were isolated from different soils, and their genetic and phenotypic characteristics were investigated. analysis of the 16s rdna sequence showed that the isolates were related to members of the genera burkholderia, pseudomonas, sphingomonas, cupriavidus, corynebacterium, and arthrobacter. among the 27 isolates, 12 different chromosomal dna fingerprinting patterns were obtained by polymerase chain reaction (pcr) amplification of repetitive extragenic p ...200919307758
four novel arthrobacter species isolated from filtration substrate.four gram-positive, non-motile, non-spore-forming bacterial strains, lc4(t), lc6(t), lc10(t) and lc13(t), were isolated from a filtration substrate made from trass, a volcanic rock, and their taxonomic positions were investigated by a polyphasic taxonomic approach. the novel strains grew over a temperature range of 5-40 degrees c, at ph values of 6-11 and in the presence of 3-7 % (w/v) nacl. a phylogenetic tree based on 16s rrna gene sequences showed the novel strains formed a distinct evolution ...200919329620
enzymatic glycosylation of triazole-linked glcnac/glc-peptides: synthesis, stability and anti-hiv activity of triazole-linked hiv-1 gp41 glycopeptide c34 analogues.long-lasting sweet proteins: the chemoenzymatic synthesis of a triazole (t)-linked glycosylated c34 fragment from hiv-1 gp41 is described. the glycopeptide shows high solubility, excellent fusion inhibition, and as shown in the graph, promising protease resistance. endoglycosidase-catalyzed transglycosylation of triazole-linked glucose (glc) and n-acetylglucosamine (glcnac)-containing dipeptides and polypeptides was achieved by using synthetic sugar oxazoline as the donor substrate. it was found ...200919353609
contribution of flavin covalent linkage with histidine 99 to the reaction catalyzed by choline oxidase.the fad-dependent choline oxidase has a flavin cofactor covalently attached to the protein via histidine 99 through an 8alpha-n(3)-histidyl linkage. the enzyme catalyzes the four-electron oxidation of choline to glycine betaine, forming betaine aldehyde as an enzyme-bound intermediate. the variant form of choline oxidase in which the histidine residue has been replaced with asparagine was used to investigate the contribution of the 8alpha-n(3)-histidyl linkage of fad to the protein toward the re ...200919398559
biodegradation of phenanthrene and pyrene in compost-amended soil.this study investigated the biodegradation of the polycyclic aromatic hydrocarbons (pahs) phenanthrene and pyrene in compost and compost-amended soil. the degradation rates of the two pahs were phenanthrene>pyrene. the degradation of pah was enhanced when the two pahs were present simultaneously in the soil. the addition of either of the two types of compost (straw and animal manure) individually enhanced pah degradation. compost samples were separated into fractions with various particle size r ...200919412845
high yield synthesis of 12-aminolauric acid by "enzymatic transcrystallization" of omega-laurolactam using omega-laurolactam hydrolase from acidovorax sp. t31.the genes encoding omega-laurolactam hydrolases from cupriavidus sp. t7, acidovorax sp. t31, cupriavidus sp. u124, and sphingomonas sp. u238 were cloned and sequenced. nucleotide and amino acid sequence analysis of the four genes indicated that the primary structures of these omega-laurolactam hydrolases are significantly similar to the 6-aminohexanoate-cyclic-dimer hydrolase (ec 3.5.2.12). these genes were expressed in escherichia coli, and the omega-laurolactam hydrolysing activity of the reco ...200919420719
uptake of l-nicotine and of 6-hydroxy-l-nicotine by arthrobacter nicotinovorans and by escherichia coli is mediated by facilitated diffusion and not by passive diffusion or active transport.the mechanism by which l-nicotine is taken up by bacteria that are able to grow on it is unknown. nicotine degradation by arthrobacter nicotinovorans, a gram-positive soil bacterium, is linked to the presence of the catabolic megaplasmid pao1. l-[(14)c]nicotine uptake assays with a. nicotinovorans showed transport of nicotine across the cell membrane to be energy-independent and saturable with a k(m) of 6.2+/-0.1 microm and a v(max) of 0.70+/-0.08 micromol min(-1) (mg protein)(-1). this is in ac ...200919443550
industrial production of difructose anhydride iii (dfa iii) from crude inulin extracted from chicory roots using arthrobacter sp. h65-7 fructosyltransferase.a practical, economical, and industrial process for the enzymatic production of difructose anhydride iii (dfa iii) was investigated for crude inulin prepared from chicory roots using arthrobacter sp. h65-7 fructosyltransferase. a comparable level of dfa iii production to that from commercial inulin was obtained using crude inulin, suggesting the feasibility of this production process.200919269589
membrane bioreactor treatment of a simulated metalworking fluid wastewater containing ethylenediaminetetraacetic acid and dicyclohexylamine.membrane bioreactors (mbrs) have been installed at automotive plants to treat metalworking fluid (mwf) wastewaters, which are known to contain toxic and/or recalcitrant organic compounds. a laboratory study was conducted to evaluate treatment of a simulated wastewater prepared from a semisynthetic mwf, which contains two such compounds, dicyclohexylamine (dcha) and ethylenediaminetetraacetic acid (edta). primary findings were as follows: during stable operating periods, almost all chemical oxyge ...200919445324
the x-ray crystal structure of an arthrobacter protophormiae endo-beta-n-acetylglucosaminidase reveals a (beta/alpha)(8) catalytic domain, two ancillary domains and active site residues key for transglycosylation activity.glycoside hydrolase family gh85 is a family of endo-beta-n-acetylglucosaminidases that is responsible for the hydrolysis of beta-1,4 linkage in the n,n-diacetylchitobiose core of n-linked glycans. the endo-beta-n-acetylglucosaminidase from arthrobacter protophormiae (endo-a) is of particular interest, given its increasing use for the chemoenzymatic synthesis of bespoke n-glycans using n-glycan oxazolines as glycosyl donors. the e173q variant of endo-a is especially attractive for synthesis, as i ...200919327363
the presence of embedded bacterial pure cultures in agar plates stimulate the culturability of soil bacteria.traditional methods for bacterial cultivation recover only a small fraction of bacteria from all sorts of natural environments, and attempts have been made to improve the bacterial culturability. here we describe the development of a cultivation method, based on the embedment of pure bacterial cultures in between two layers of agar. plates containing either embedded pseudomonas putida or arthrobacter globiformis resulted in higher numbers of cfus of soil bacteria (21% and 38%, respectively) afte ...200919699242
arthrobacter halodurans sp. nov., a new halotolerant bacterium isolated from sea water.a novel gram-positive, halotolerant, non-sporulating, non-motile, catalase-positive, oxidase-negative and aerobic bacterium, designated strain jsm 078085(t), was isolated from sea water collected from the south china sea. strain jsm 078085(t) exhibited a rod-coccus growth cycle and produced a yellow pigment. the strain was able to grow in the presence of 0-12% (w/v) nacl and at ph 6.0-9.5 and 4-35 degrees c; optimum growth was observed at ph 7.0 and 25-30 degrees c in the absence of nacl. the pe ...200919337850
eric-pcr-based strain-specific detection of phenol-degrading bacteria in activated sludge of wastewater treatment systems.to evaluate the use of enterobacterial repetitive intergenic consensus pcr (eric-pcr)-derived probes and primers to specifically detect bacterial strains in an activated sludge microbial community.200919708883
effect of immobilization of a bacterial consortium on diuron dissipation and community dynamics.this work intended to study the relationship between diuron herbicide dissipation and the population dynamics of co-cultivated delftia acidovorans wdl34 (wdl34) and arthrobacter sp. n4 (n4) for different cell formulations: free cells or immobilization in ca-alginate beads of one or both strains. gfp-tagged wdl34 and n4 gram staining allowed analyzing the cell growth and distribution of each strain in both beads and culture medium in the course of the time. compared to the free cell co-culture of ...200919386487
c29 olefinic hydrocarbons biosynthesized by arthrobacter species.arthrobacter aurescens tc1, arthrobacter chlorophenolicus a6, arthrobacter crystallopoietes, and arthrobacter oxydans produce long-chain monoalkenes, predominantly cis-3,25-dimethyl-13-heptacosene. four other arthrobacter strains did not form alkenes. the level of cis-3,25-dimethyl-13-heptacosene in arthrobacter chlorophenolicus a6 remained proportional to cell mass during growth. cis-3,25-dimethyl-13-heptacosene did not support growth of a. chlorophenolicus a6.200919168653
gene cloning, expression, and characterization of a novel trehalose synthase from arthrobacter aurescens.trehalose synthase (tres) is an intramolecular transglycosylase. it specially catalyzes the conversion of maltose and trehalose. in this study, a novel tres gene, which had a length of 1,797 bp and encoded 598 amino acids, was cloned from arthrobacter aurescens cgmcc 1.1892 and expressed in escherichia coli. thin layer chromatography results indicated that it could catalyze the conversion between maltose and trehalose in one step. however, the ion chromatography results showed that, as a byprodu ...200919172263
targeting prokaryotic choline oxidase into chloroplasts enhance the potential of photosynthetic machinery of plants to withstand oxidative damage.chloroplasts from plants of transgenic lines expressing prokaryotic choline oxidase gene (the coda(ps) gene; genbank accession number-ay589052) and wild-type of chickpea and indian mustard were evaluated for their efficacy to withstand photoinhibitory damage, by exposing them to high light intensity ( approximately 1200micromolm(-2)s(-1) photon flux density) at 10 and 25 degrees c. western analysis confirmed presence of choline oxidase in chloroplasts of only transgenic lines. the loss in ps ii ...200919186067
a novel nicotine catabolic plasmid pmh1 in pseudomonas sp. strain hf-1.attempts were made to acquire a plasmid-loss mutant via various methods (spontaneous mutation, sds, and mitomycin c), among which the method involving mitomycin c (10 microg/ml) has been proven successful. concomitant with the loss of the plasmid in pseudomonas sp. strain hf-1, the cured derivative was identified as having a nicotine-negative (nic-) phenotype, named mutant strain 6-13 (nic-). after plasmids were transferred from strain hf-1 (named plasmid pmh1) to the mutant strain 6-13, the mut ...200919370065
improvement of steroid biotransformation with hydroxypropyl-beta-cyclodextrin induced complexation.the inclusion complexes induced by cyclodextrins and its derivates have been shown previously to enhance the biotransformation of hydrophobic compounds. using hydroxypropyl-beta-cyclodextrin (hp-beta-cd; 20% w/v), the water solubility of cortisone acetate increased from 0.039 to 7.382 g l(-1) at 32 degrees c. the solubilization effect of hp-beta-cd was far superior to dimethylformamide (dmf) and ethanol. the dissolution rate also significantly increased in the presence of hp-beta-cd. the enzymat ...200919189059
proposal of sinomonas flava gen. nov., sp. nov., and description of sinomonas atrocyanea comb. nov. to accommodate arthrobacter atrocyaneus.a novel actinomycete strain, designated cw 108(t), was isolated from a forest soil in anhui province, china. the cells were strictly aerobic, non-motile, bent rods. the strain grew optimally at 30-37 degrees c and ph 6.0-8.0. chemotaxonomically, the peptidoglycan type was a3alpha, the cell-wall sugars contained galactose, mannose and ribose, the polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylmonomethylethanolamine, the major fatty acids were ...200919196763
arthrobacter phenanthrenivorans sp. nov., to accommodate the phenanthrene-degrading bacterium arthrobacter sp. strain sphe3.a novel phenanthrene-degrading bacterium, designated strain sphe3(t), was isolated from a creosote-contaminated soil in greece. cells were non-motile, gram-positive, aerobic, and rod- to coccus-shaped. the strain was isolated on the basis of formation of a clear zone on agar plates sprayed with phenanthrene. optimal growth occurred at 30 degrees c. the g+c content of the dna was 65.7 mol%. the polar lipid pattern of strain sphe3(t) consisted of phosphatidylethanolamine, phosphatidylglycerol and ...200919196765
glycosynthases enable a highly efficient chemoenzymatic synthesis of n-glycoproteins carrying intact natural n-glycans.homogeneous n-glycoproteins carrying defined natural n-glycans are essential for detailed structural and functional studies. the transglycosylation activity of the endo-beta-n-acetylglucosaminidases from arthrobacter protophormiae (endo-a) and mucor hiemalis (endo-m) holds great potential for glycoprotein synthesis, but the wild-type enzymes are not practical for making glycoproteins carrying native n-glycans because of their predominant activity for product hydrolysis. in this article, we repor ...200919199609
effects of proteus vulgaris growth on the establishment of a cheese microbial community and on the production of volatile aroma compounds in a model cheese.to investigate the impact of proteus vulgaris growth on a multispecies ecosystem and on volatile aroma compound production during cheese ripening.200919426267
purification and characterization of arsenite oxidase from arthrobacter sp.the chemolithoautotroph, arthrobacter sp.15b oxidizes arsenite to arsenate using a membrane bound arsenite oxidase. the enzyme arsenite oxidase is purified to its homogeneity and identified using maldi-tof ms analysis. upon further characterization, it was observed that the enzyme is a heterodimer showing native molecular mass as approximately 100 kda and appeared as two subunits of approximately 85 kda lsu and 14 kda ssu on sds-page. the v(max) and k(m) values of the enzyme was found to be 2.45 ...200919214757
thermal analysis of whole bacterial cells exposed to potassium permanganate using differential scanning calorimetry: a biphasic dose-dependent response to stress.the dsc technique applied to the study of the toxic impact of permanganate on bacterial cell culture detected the lack of linearity in the dose-response effect. the results were confirmed by the traditional assay of colony forming ability. the changed pattern of thermal spectra of a. oxydans at permanganate treatment, the measurement of the total heat capacity and the temperature of dnp complex demonstrate the possibility to verify the toxic impact in dependence of concentrations value.200919219375
global proteomic analysis of the chromate response in arthrobacter sp. strain fb24.a global proteomic evaluation of the response of arthrobacter sp. strain fb24 to 5 and 20 mm cr(vi) was conducted using both two-dimensional gel electrophoresis (2-dge) and liquid chromatography coupled with tandem mass spectrometry (lc/lc-ms/ms). the changes in protein expression found with 2-dge indicate alterations in central metabolism and amino acid synthesis. proteome coverage increased from 22% with 2-dge to 71% with lc/lc-ms/ms. the proteins exhibiting the highest levels of expression un ...200919231868
mating triggers dynamic immune regulations in wood ant queens.mating can affect female immunity in multiple ways. on the one hand, the immune system may be activated by pathogens transmitted during mating, sperm and seminal proteins, or wounds inflicted by males. on the other hand, immune defences may also be down-regulated to reallocate resources to reproduction. ants are interesting models to study post-mating immune regulation because queens mate early in life, store sperm for many years, and use it until their death many years later, while males typica ...200919170815
preferential hydrolysis of aberrant intermediates by the type ii thioesterase in escherichia coli nonribosomal enterobactin synthesis: substrate specificities and mutagenic studies on the active-site residues.the type ii thioesterase enth is a hotdog fold protein required for optimal nonribosomal biosynthesis of enterobactin in escherichia coli. its proposed proofreading activity in the biosynthesis is confirmed by its efficient restoration of enterobactin synthesis blocked in vitro by analogs of the cognate precursor 2,3-dihydroxybenzoate. steady-state kinetic studies show that enth recognizes the phosphopantetheine group and the pattern of hydroxylation in the aryl moiety of its thioester substrate ...200919193103
endo-beta-n-acetylglucosaminidase-catalyzed polymerization of beta-glcp-(1-->4)-glcpnac oxazoline: a revisit to enzymatic transglycosylation.an alternative synthesis of beta-glcp-(1-->4)-glcpnac oxazoline is described, and its enzymatic reaction with the endo-beta-n-acetylglucosaminidase from arthrobacter protophormiae (endo-a) was re-investigated. under normal transglycosylation conditions with a catalytic amount of enzyme, endo-a showed only marginal activity for transglycosylation with the disaccharide oxazoline, consistent with our previous observations. however, when used in a relatively large quantity, endo-a could promote the ...200919193364
Refresh
firstprev
...21222324
nextlast
Displaying items 2001 - 2100 of 2332