atomic resolution structures of resting-state, substrate- and product-complexed cu-nitrite reductase provide insight into catalytic mechanism.copper-containing nitrite reductases catalyze the reduction of nitrite to nitric oxide (no), a key step in denitrification that results in the loss of terrestrial nitrogen to the atmosphere. they are found in a wide variety of denitrifying bacteria and fungi of different physiology from a range of soil and aquatic ecosystems. structural analysis of potential intermediates in the catalytic cycle is an important goal in understanding enzyme mechanism. using "crystal harvesting" and substrate-soaki ...200516093314
alcaligenes faecalis subsp. phenolicus subsp. nov. a phenol-degrading, denitrifying bacterium isolated from a graywater bioprocessor.a gram (-) coccobacillary bacterium, j(t), was isolated from a graywater bioprocessor. 16s rrna and biochemical analysis has revealed strain j(t) closely resembles alcaligenes faecalis atcc 8750t and a. faecalis subsp. parafaecalis dsm 13975t, but is a distinct, previously uncharacterized isolate. strain j(t), along with the type strain of a. faecalis and its previously described subspecies share the ability to aerobically degrade phenol. the degradation rates of phenol for strain j(t) and refer ...200516094869
postoperative endophthalmitis due to an unusual pathogen: alcaligenes faecalis. 200616138111
isolation and characterization of a chlorpyrifos and 3,5,6-trichloro-2-pyridinol degrading bacterium.a bacterium, isolated from contaminated soils around a chemical factory and named strain dsp3 was capable of biodegrading both chlorpyrifos and 3,5,6-trichloro-2-pyridinol. based on the results of phenotypic features, phylogenetic similarity of 16s rrna gene sequences, dna g+c content, and dna homology between strain dsp3 and reference strains, strain dsp3 was identified as alcaligenes faecalis. chlorpyrifos was utilized as the sole source of carbon and phosphorus by strain dsp3. we examined the ...200516143458
intestinal protozoa and associated bacteria in captive houbara bustards (chlamydotis undulata) in the united arab emirates.a protozoal survey was carried out in 114 captive houbara bustards (chlamydotis undulata) in the united arab emirates. trichomonas gallinarum, chilomastix gallinarum, giardia spp. and lophomonas spp. were detected from faecal samples of 49 (43%) captive houbara bustards. culture and identification studies were carried out to assess associated bacteria. the bacteria isolated from birds negative to protozoa included enterococcus spp., aerococcus spp., micrococci spp., proteus spp., enterobacter sp ...199916147554
dissimilatory iron reduction and odor indicator abatement by biofilm communities in swine manure microcosms.animal waste odors arising from products of anaerobic microbial metabolism create community relations problems for livestock producers. we investigated a novel approach to swine waste odor reduction: the addition of fecl(3), a commonly used coagulant in municipal wastewater treatment, to stimulate degradation of odorous compounds by dissimilatory iron-reducing bacteria (dirb). two hypotheses were tested: (i) fecl(3) is an effective source of redox-active ferric iron (fe(3+)) for dissimilatory re ...200516151075
new chitosan-degrading strains that produce chitosanases similar to choa of mitsuaria chitosanitabida.the betaproteobacterium mitsuaria chitosanitabida (formerly matsuebacter chitosanotabidus) 3001 produces a chitosanase (choa) that is classified in glycosyl hydrolase family 80. while many chitosanase genes have been isolated from various bacteria to date, they show limited homology to the m. chitosanitabida 3001 chitosanase gene (choa). to investigate the phylogenetic distribution of chitosanases analogous to choa in nature, we identified 67 chitosan-degrading strains by screening and investiga ...200516151097
presence of two different active nirs nitrite reductase genes in a denitrifying thauera sp. from a high-nitrate-removal-rate reactor.the nirs nitrite reductase genes were studied in two strains (strains 27 and 28) isolated from two denitrifying reactors and characterized as thauera according to their 16s rrna gene sequences. strain 28 contains a single nirs sequence, which is related to the nirs of thauera mechernichensis, and strain 27 contains two nirs sequences; one is similar to the nirs sequence from thauera mechernichensis (gene 2), but the second one (gene 8) is from a separate clade with nirs from pseudomonas stutzeri ...200516151169
antibacterial activity of essential oils from australian native date, of the australian essential oils, only tea tree (melaleuca alternifolia) and eucalyptus spp. have undergone extensive investigation. in this study a range of australian essential oils, including those from anethole anisata, callistris glaucophyllia, melaleuca spp. and thyptomine calycina, were assayed for in vitro antibacterial activity. m. alternifolia was also included for comparison purposes. activity was determined using standard disc diffusion assays with each oil assayed at 100%, ...200516161028
characteristics of ammonium removal by heterotrophic nitrification-aerobic denitrification by alcaligenes faecalis no. 4.alcaligenes faecalis no. 4 has heterotrophic nitrification and aerobic denitrification abilities. by taking the nitrogen balance under different culture conditions, 40-50% of removed nh4+-n was denitrified and about one-half of removed nh4+-n was converted to intracellular nitrogen. the maximum ammonium removal rate of no. 4 (28.9 mg-n/l/h) and its denitrification rate at high-strength nh4+-n of about 1200 ppm in aerated batch experiments at a c/n ratio of 10 were 5-40 times higher than those of ...200516198262
use of shell-vial cell culture assay for isolation of bacteria from clinical specimens: 13 years of experience.the shell-vial culture assay is performed routinely in our laboratory. recently we revisited our experience of using the shell-vial culture assay for the isolation of microorganisms from various clinical samples. over a 13-year period, we have isolated 580 bacterial strains (5%) from 11,083 clinical samples tested. over the same period, 285 isolates of rickettsiae, bartonellae, or coxiella burnetii were cultured from a total of 7,102 samples tested. these isolates include 55 rickettsia sp. isola ...200516207953
evaluation of a rapid direct assay for identification of bacteria and the mec a and van genes from positive-testing blood cultures.we performed the first evaluation of a dna strip assay (genotype blood culture; hain lifescience, nehren, germany) for the detection of the most relevant bacterial sepsis pathogens directly from positive bactec blood culture bottles (becton dickinson, heidelberg, germany). the test comprises two panels, one for the direct species identification of important gram-positive cocci and the other for gram-negative rods. additionally, detection of the mec a and the van genes are implemented. the genoty ...200516207992
extended-spectrum beta-lactamases: a clinical update.extended-spectrum beta-lactamases (esbls) are a rapidly evolving group of beta-lactamases which share the ability to hydrolyze third-generation cephalosporins and aztreonam yet are inhibited by clavulanic acid. typically, they derive from genes for tem-1, tem-2, or shv-1 by mutations that alter the amino acid configuration around the active site of these beta-lactamases. this extends the spectrum of beta-lactam antibiotics susceptible to hydrolysis by these enzymes. an increasing number of esbls ...200516223952
influence of growth phase on bacterial cell electrokinetic characteristics examined by soft particle electrophoresis theory.the influence of incubation time on the electrokinetic properties of escherichia coli, pseudomonas putida, alcaligenes faecalis, and alcaligenes sp., was examined by electrophoretic mobility measurements and the results were discussed based on ohshima's soft particle theory. the electrophoretic mobility of e. coli plotted against incubation time revealed that the mobility gradually increased from the outset of incubation to 7 h, which corresponded to the exponential growth and early stationary p ...200316256681
analytical verification of a pcr assay for identification of bordetella avium.bordetella avium is the etiologic agent of turkey coryza or bordetellosis, a respiratory disease responsible for substantial economic losses to the turkey industry. at present, identification of this bacterium relies on isolation and biochemical testing. although a pcr for the detection of b. avium was proposed a number of years ago, lack of analytical verification precludes its use as a diagnostic tool. furthermore, a number of details pertaining to the reaction conditions used are missing or u ...200516272488
tryptophan tryptophylquinone cofactor biogenesis in the aromatic amine dehydrogenase of alcaligenes faecalis. cofactor assembly and catalytic properties of recombinant enzyme expressed in paracoccus denitrificans.the heterologous expression of tryptophan trytophylquinone (ttq)-dependent aromatic amine dehydrogenase (aadh) has been achieved in paracoccus denitrificans. the aaubeda genes and orf-2 from the aromatic amine utilization (aau) gene cluster of alcaligenes faecalis were placed under the regulatory control of the mauf promoter from p. denitrificans and introduced into p. denitrificans using a broad-host-range vector. the physical, spectroscopic and kinetic properties of the recombinant aadh were i ...200516279953
alcaligenes aquatilis sp. nov., a novel bacterium from sediments of the weser estuary, germany, and a salt marsh on shem creek in charleston harbor, usa.four nitrite-dissimilating strains, isolated from weser estuary sediments, were investigated using a polyphasic taxonomic approach. phylogenetic analysis based on 16s rrna gene sequences indicated that these strains belong to the 'betaproteobacteria' and are related to the genus alcaligenes. the highest level of sequence similarity (100 %) was found with strain m3a (=atcc 700596), a dimethyl sulfide-producing marine isolate that was included in this study. dna-dna hybridizations between the five ...200516280529
the substrate-bound type 2 copper site of nitrite reductase: the nitrogen hyperfine coupling of nitrite revealed by pulsed epr.a pulsed electron paramagnetic resonance study has been performed on the type 2 copper site of nitrite reductase (nir) from alcaligenes faecalis. the h145a mutant, in which histidine 145 is replaced by alanine, was studied by eseem and hyscore experiments at 9 ghz on frozen solutions. this mutant contains a reduced type 1 copper site which allowed a selective investigation of the type 2 site of h145a and of its nitrite-bound form h145a (no2(-)). the experiments yielded hyperfine and quadrupole p ...200516285722
l-cysteate sulpho-lyase, a widespread pyridoxal 5'-phosphate-coupled desulphonative enzyme purified from silicibacter pomeroyi dss-3(t).quantitative utilization of l-cysteate (2-amino-3-sulphopropionate) as the sole source of carbon and energy for growth of the aerobic, marine bacterium silicibacter pomeroyi dss-3(t) was observed. the sulphonate moiety was recovered in the medium largely as sulphite, and the appropriate amount of the ammonium ion was also observed. genes [suyab (3-sulpholactate sulpho-lyase)] encoding the known desulphonation reaction in cysteate degradation were absent from the genome, but a homologue of a puta ...200616302849
novel cyclic lipodepsipeptide from pseudomonas syringae pv. lachrymans strain 508 and syringopeptin antimicrobial activities.the syringopeptins are a group of antimicrobial cyclic lipodepsipeptides produced by several plant-associated pseudomonads. a novel syringopeptin, sp508, was shown to be produced as two homologs (a and b) by pseudomonas syringae pv. lachrymans strain 508 from apple and to structurally resemble syringopeptin sp22. sp508 differed from sp22 and other syringopeptins by having three instead of four alpha,beta-unsaturated amino acids and a longer beta-hydroxy acyl chain. both sp508 and sp22 displayed ...200516304170
class 1 integrons and tetracycline resistance genes in alcaligenes, arthrobacter, and pseudomonas spp. isolated from pigsties and manured soil.the presence of tetracycline resistance (tc(r)) genes and class i integrons (in-1), and their ability to cotransfer were investigated in tc(r) gram-negative (185 strains) and gram-positive (72 strains) bacteria from danish farmland and pigsties. the isolates belonged to the groups or species escherichia coli, enterobacter spp., arthrobacter spp., alcaligenes spp., pseudomonas spp., and corynebacterium glutamicum. the 257 isolates were screened for in-1. eighty-one of the gram-negative isolates w ...200516332771
tem-21 extended-spectrum beta-lactamase in a clinical isolate of alcaligenes faecalis from a nursing home. 200616344284
rapid screen for bacteria degrading water-insoluble, solid hydrocarbons on agar plates.a rapid procedure was devised for detecting on solid media bacteria able to degrade water-insoluble, solid hydrocarbons such as the polycyclic aromatic hydrocarbons phenanthrene, anthracene, and biphenyl. after alcaligenes faecalis afk2 was inoculated on a plate containing mineral salts agar, an ethereal solution of phenanthrene (about 10%, wt/vol) was sprayed on the surface of the plate, and the plate was incubated at 30 degrees c for 2 to 3 days. colonies showing degradation were surrounded wi ...198216345951
relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers.biogenic emissions of nitric and nitrous oxides have important impacts on the photochemistry and chemistry of the atmosphere. although biogenic production appears to be the overwhelming source of n(2)o, the magnitude of the biogenic emission of no is very uncertain. in soils, possible sources of no and n(2)o include nitrification by autotrophic and heterotrophic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. the availabili ...198616347068
microbiological degradation of malodorous substances of swine waste under aerobic conditions.phenol, p-cresol, and volatile fatty acids (vfa; acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids) were used as odor indicators of swine waste. aeration of the waste allowed the indigenous microorganisms to grow and degrade these malodorous substances. the time required for degradation of these substances varied according to the waste used, and it was not necessarily related to their concentrations. using a minimal medium which contained one of the malodorous compounds as so ...198716347254
purification and characterization of d-aminoacylase from alcaligenes faecalis da1.a d-aminoacylase from alcaligenes faecalis da1 has been purified to homogeneity by a simple purification procedure with two columns, fractogel deae-650 and hw-50. the specific activity of the purified enzyme was found to be 580 u/mg of protein with n-acetyl-dl-methionine as the reaction substrate. the apparent molecular weight and isoelectric point of this enzyme were determined to be 55,000 and 5.4, respectively.199116348465
differentiation of gram-negative, nonfermentative bacteria isolated from biofilters on the basis of fatty acid composition, quinone system, and physiological reaction profiles.gram-negative, nonfermentative bacteria isolated from biofilters for off-gas treatment of animal-rendering-plant emissions were differentiated by whole-cell fatty acid analysis, quinone analysis, and numerical taxonomy based on their physiological reaction profiles. the last system consisted of 60 physiological tests and was arranged as a microtest system on microtitration plates. based on fatty acid analyses, 31 isolates were separated into six clusters and five single-member clusters. the isol ...199216348724
nitrospira-like bacteria associated with nitrite oxidation in freshwater aquaria.oxidation of nitrite to nitrate in aquaria is typically attributed to bacteria belonging to the genus nitrobacter which are members of the alpha subdivision of the class proteobacteria. in order to identify bacteria responsible for nitrite oxidation in aquaria, clone libraries of rrna genes were developed from biofilms of several freshwater aquaria. analysis of the rdna libraries, along with results from denaturing gradient gel electrophoresis (dgge) on frequently sampled biofilms, indicated the ...199816349486
purification and properties of a polyester polyurethane-degrading enzyme from comamonas acidovorans tb-35.a polyester polyurethane (pur)-degrading enzyme, pur esterase, derived from comamonas acidovorans tb-35, a bacterium that utilizes polyester pur as the sole carbon source, was purified until it showed a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page). this enzyme was bound to the cell surface and was extracted by addition of 0.2% n,n-bis(3-d-gluconamidopropyl)deoxycholamide (deoxy-bigchap). the results of gel filtration and sds-page showed that the pur esteras ...199816349494
ligands for the beta-glucan receptor, dectin-1, assigned using "designer" microarrays of oligosaccharide probes (neoglycolipids) generated from glucan polysaccharides.dectin-1 is a c-type lectin-like receptor on leukocytes that mediates phagocytosis and inflammatory mediator production in innate immunity to fungal pathogens. dectin-1 lacks residues involved in calcium ligation that mediates carbohydrate-binding by classical c-type lectins; nevertheless, it binds zymosan, a particulate beta-glucan-rich extract of saccharomyces cerevisiae, and binding is inhibited by polysaccharides rich in beta1,3- or both beta1,3- and beta1,6-linked glucose. the oligosacchari ...200616371356
development and evaluation of a real-time pcr assay targeting the type iii secretion system of burkholderia we report on the development of a discriminatory real-time assay for the rapid identification of burkholderia pseudomallei isolates and the evaluation of this assay for sensitivity against related species and detection in spiked human blood samples. the assay targets a 115-base-pair region within orf2 of the b. pseudomallei type iii secretion system gene cluster and distinguishes b. pseudomallei from other microbial species. assay performance was evaluated with 224 geographically, temporall ...200616390953
plasmid-mediated high-level gentamicin resistance among enteric bacteria isolated from pet turtles in louisiana.the sale of small turtles is banned by the food and drug administration from the u.s. market due to concerns about their excretion of salmonella spp. to produce a safe pet for the export market, the louisiana pet turtle industry uses gentamicin sulfate baths (1,000 microg/ml) to eradicate salmonella spp. from turtle eggs. in 1999, we analyzed bacterial samples recovered from turtle farms and found that strains of salmonella enterica subsp. arizonae and other bacteria, such as enterobacter cloaca ...200616391058
complex regulation of arsenite oxidation in agrobacterium tumefaciens.seminal regulatory controls of microbial arsenite [as(iii)] oxidation are described in this study. transposon mutagenesis of agrobacterium tumefaciens identified genes essential for as(iii) oxidation, including those coding for a two-component signal transduction pair. the transposon interrupted a response regulator gene (referred to as aoxr), which encodes an ntrc-like protein and is immediately downstream of a gene (aoxs) encoding a protein with primary structural features found in sensor hist ...200616428412
a na+:h+ antiporter and a molybdate transporter are essential for arsenite oxidation in agrobacterium tumefaciens.transposon tn5-b22 mutagenesis was used to identify genetic determinants required for arsenite [as(iii)] oxidation in an agrobacterium tumefaciens soil isolate, strain 5a. in one mutant, the transposon interrupted modb, which codes for the permease component of a high-affinity molybdate transporter. in a second mutant, the transposon insertion occurred in mrpb, which is part of a seven-gene operon encoding an mrp-type na+:h+ antiporter complex. complementation experiments with mod and mrp operon ...200616452441
interaction of beta-1,3-glucan with its recognition protein activates hemolymph proteinase 14, an initiation enzyme of the prophenoloxidase activation system in manduca sexta.a serine proteinase pathway in insect hemolymph leads to prophenoloxidase activation, an innate immune response against pathogen infection. in the tobacco hornworm manduca sexta, recombinant hemolymph proteinase 14 precursor (pro-hp14) interacts with peptidoglycan, autoactivates, and initiates the proteinase cascade (ji, c., wang, y., guo, x., hartson, s., and jiang, h. (2004) j. biol. chem. 279, 34101-34106). here, we report the purification and characterization of pro-hp14 from the hemolymph o ...200616461344
structure-based stabilization of an enzyme: the case of penicillin acylase from alcaligenes faecalis.the modeled structure of penicillin acylase from alcaligenes faecali (afpga) was constructed by comparative modeling with the modeller program. candidate positions that could be replaced with cysteine were estimated by scanning the modeled structure of afpga with the program modip (modeling disulfide bond in protein). the mutant q3c/p751c had a higher optimum temperature by three degrees than that of the wild type afpga. the half life of the double mutant q3c/p751c at 55 degrees c was increased ...200616472081
health considerations regarding horizontal transfer of microbial transgenes present in genetically modified crops.the potential effects of horizontal gene transfer on human health are an important item in the safety assessment of genetically modified organisms. horizontal gene transfer from genetically modified crops to gut microflora most likely occurs with transgenes of microbial origin. the characteristics of microbial transgenes other than antibiotic-resistance genes in market-approved genetically modified crops are reviewed. these characteristics include the microbial source, natural function, function ...200516489267
[isolation and characterization of a chlorpyrifos degrading bacteria and its bioremediation application in the soil].a strain dsp3 capable of utilizing chlorpyrifos as the sole carbon and energy sources was isolated. based on the results of phenotypic features, phylogenetic of 16s rdna sequence, dna (g + c) mol% and dna homology between strain dsp3 and reference strains, the strain dsp3 is identified as alcaligenes faecalis. the degradation rate of chlorpyrifos was at 98.6% (100 mg/l) in liquid culture medium within 18 days and nearly 100% (100 mg/kg) in soil within 20 days respectively. an addition of strain ...200516496701
resistance determinants of a highly arsenic-resistant strain of leptospirillum ferriphilum isolated from a commercial biooxidation tank.two sets of arsenic resistance genes were isolated from the highly arsenic-resistant leptospirillum ferriphilum fairview strain. one set is located on a transposon, tnlfars, and is related to the previously identified tnatcars from acidithiobacillus caldus isolated from the same arsenopyrite biooxidation tank as l. ferriphilum. tnlfars conferred resistance to arsenite and arsenate and was transpositionally active in escherichia coli. tnlfars and tnatcars were sufficiently different for them not ...200616517682
analysis of 525 samples to determine the usefulness of pcr amplification and sequencing of the 16s rrna gene for diagnosis of bone and joint infections.the 16s rrna gene pcr in the diagnosis of bone and joint infections has not been systematically tested. five hundred twenty-five bone and joint samples collected from 525 patients were cultured and submitted to 16s rrna gene pcr detection of bacteria in parallel. the amplicons with mixed sequences were also cloned. when discordant results were observed, culture and pcr were performed once again. bacteria were detected in 139 of 525 samples. culture and 16s rrna gene pcr yielded identical documen ...200616517890
pseudomonas aeruginosa bloodstream infections: risk factors and treatment outcome related to expression of the per-1 extended-spectrum beta-lactamase.bloodstream infection (bsi) due to pseudomonas aeruginosa (pa) has relevant clinical impact especially in relation to drug resistance determinants. the per-1 extended-spectrum beta-lactamase (esbl) is a common enzyme conferring high-level resistance to anti-pseudomonal cephalosporins. risk factors and treatment outcome of bsi episodes caused by per-1-positive pa (per-1-pa) strains were compared to those caused by esbl-negative pa isolates (esbl-n-pa).200616542460
the sulfonated osmolyte n-methyltaurine is dissimilated by alcaligenes faecalis and by paracoccus versutus with release of methylamine.selective enrichments yielded bacterial cultures able to utilize the osmolyte n-methyltaurine as sole source of carbon and energy or as sole source of fixed nitrogen for aerobic growth. strain mt1, which degraded n-methyltaurine as a sole source of carbon concomitantly with growth, was identified as a strain of alcaligenes faecalis. stoichiometric amounts of methylamine, whose identity was confirmed by matrix-assisted, laser-desorption ionization time-of-flight mass spectrometry, and of sulfate ...200616549680
enhancing enzymatic activity of penicillin g acylase by coexpressing pcm gene.penicillin g acylase (pga; e.c. is an important enzyme which has broad applications in industries of beta-lactim antibiotics production. in this study, a promising pga gene from alcaligenes faecalis (afpga) and another pcm gene encoding protein isoaspartate methyltransferase (pimt) were constructed into pet43.1a((+)) and pet28a((+)), respectively. the recombinant plasmids petafpga and petpcm were transformed into the same host cell escherichia coli bl21 (de3). results suggested that th ...200616550378
comparison of spheroplast induction in alcaligenes faecalis by three different agents.lark, cynthia (saint louis university, st. louis, mo.) and robert schichtel. comparison of spheroplast induction in alcaligenes faecalis by three different agents. j. bacteriol. 84:1241-1244. 1962.-alcaligenes faecalis strain lb was exposed to different concentrations of cycloserine, d-methionine, or penicillin. the time course of spheroplast induction by these agents was measured as a function of their concentration. the results were consistent with models in which cycloserine reversibly inhibi ...196216561981
selection and identification of bacteria isolated from waste crude oil with polycyclic aromatic hydrocarbons removal capacities.fifteen bacterial strains isolated from solid waste oil samples were selected due to their capacity of growing in the presence of hydrocarbons. the isolates were identified by pcr of the 16s rdna gene using fd1 and rd1 primers. the majority of the strains belonged to genera bacillus, bacillus pumilus (eight strains) and bacillus subtilis (two strains). besides, three strains were identified as micrococcus luteus, one as alcaligenes faecalis and one strain as enterobacter sp. growth of the above- ...200616564960
a rearranging ligand enables allosteric control of catalytic activity in copper-containing nitrite cu-containing nitrite reductase from alcaligenes faecalis s-6 the axial methionine ligand of the type-1 site was replaced (m150g) to make the copper ion accessible to external ligands that might affect the enzyme's catalytic activity. the type-1 site optical spectrum of m150g (a(460)/a(600)=0.71) differs significantly from that of the native nitrite reductase (a(460)/a(600)=1.3). the midpoint potential of the type-1 site of nitrite reductase m150g (e(m)=312(+/-5)mv versus hydrogen) is higher ...200616574144
castellaniella gen. nov., to accommodate the phylogenetic lineage of alcaligenes defragrans, and proposal of castellaniella defragrans gen. nov., comb. nov. and castellaniella denitrificans sp. nov.comparative 16s rrna gene sequence analysis indicates that two distinct sublineages exist within the genus alcaligenes: the alcaligenes faecalis lineage, comprising alcaligenes aquatilis and a. faecalis (with the three subspecies a. faecalis subsp. faecalis, a. faecalis subsp. parafaecalis and a. faecalis subsp. phenolicus), and the alcaligenes defragrans lineage, comprising a. defragrans. this phylogenetic discrimination is supported by phenotypic and chemotaxonomic differences. it is proposed ...200616585701
16s rrna gene sequencing versus the api 20 ne system and the vitek 2 id-gnb card for identification of nonfermenting gram-negative bacteria in the clinical laboratory.over a period of 26 months, we have evaluated in a prospective fashion the use of 16s rrna gene sequencing as a means of identifying clinically relevant isolates of nonfermenting gram-negative bacilli (non-pseudomonas aeruginosa) in the microbiology laboratory. the study was designed to compare phenotypic with molecular identification. results of molecular analyses were compared with two commercially available identification systems (api 20 ne, vitek 2 fluorescent card; biomérieux, marcy l'etoil ...200616597863
cloning and sequencing of the ompa gene of enterobacter sakazakii and development of an ompa-targeted pcr for rapid detection of enterobacter sakazakii in infant formula.enterobacter sakazakii is an emerging, infant formula-borne pathogen that causes severe meningitis, meningoencephalitis, sepsis, and necrotizing enterocolitis in neonates and infants, with a high fatality rate. traditional detection methods take up to 7 days to identify e. sakazakii. the outer membrane protein a gene (ompa), along with its flanking sequences from e. sakazakii (atcc 51329), was cloned in the pgem-t easy vector and sequenced. comparison of the nucleotide and deduced amino acid seq ...200616597955
quantitative real-time legionella pcr for environmental water samples: data interpretation.quantitative legionella pcrs targeting the 16s rrna gene (specific for the genus legionella) and the mip gene (specific for the species legionella pneumophila) were applied to a total of 223 hot water system samples (131 in one laboratory and 92 in another laboratory) and 37 cooling tower samples (all in the same laboratory). the pcr results were compared with those of conventional culture. 16s rrna gene pcr results were nonquantifiable for 2.8% of cooling tower samples and up to 39.1% of hot wa ...200616597985
rapid detection of brucella spp. in blood cultures by fluorescence in situ hybridization.brucellosis is a severe systemic disease in humans. we describe a new 16s rrna-based fluorescence in situ hybridization assay that facilitates rapid and specific detection of all human pathogenic species of brucella and that can be applied directly to positive blood cultures.200616672413
stereoselective nitrile hydrolysis by immobilized whole-cell biocatalyst.the present work attempts to deal with the stability and reusability aspect of nitrilase from alcaligenes faecalis for the production of (r)-(-)-mandelic acid. four entrapment matrixes were screened to search for a suitable support, and alginate was found to have significant process advantages over its other counterparts. thermodynamic analysis allowed us to account for decreased enantioselectivity (e) as a result of immobilization. the system was also characterized based on the thiele modulus ( ...200616677036
characterization of a novel long-chain acyl-coa thioesterase from alcaligenes faecalis.a novel long-chain acyl-coa thioesterase from alcaligenes faecalis has been isolated and characterized. the protein was extracted from the cells with 1 m nacl, which required 1.5-fold, single-step purification to yield near-homogeneous preparations. in solution, the protein exists as homomeric aggregates, of mean diameter 21.6 nm, consisting of 22-kda subunits. ms/ms data for peptides obtained by trypsin digestion of the thiosterase did not match any peptide from escherichia coli thioesterases o ...200616704412
mutant afm 2 of alcaligenes faecalis for phenol biodegradation using he-ne laser irradiation.he-ne laser technology was utilized in this study to investigate the response of alcaligenes faecalis to laser stimulation. the irradiation experiments were conducted by the adjustment of the output power from 5 to 25 mw and the exposure time from 5 to 25 min. the results showed that the survival rate changed regularly with the variety of irradiation dose, and high positive mutation frequency was determined by both the energy density and the output power. the mutant strain afm 2 was obtained. ph ...200616730779
tetrathiobacter mimigardefordensis sp. nov., isolated from compost, a betaproteobacterium capable of utilizing the organic disulfide 3,3'-dithiodipropionic this study, a novel betaproteobacterium, strain dpn7(t), was isolated under mesophilic conditions from compost because of its capacity to utilize the organic disulfide 3,3'-dithiodipropionic acid. analysis of the 16s rrna gene sequence of strain dpn7(t) revealed 98.5 % similarity to that of tetrathiobacter kashmirensis lmg 22695(t). values for sequence similarity to members of the genera alcaligenes, castellaniella and taylorella, the nearest neighbours of the genus tetrathiobacter, were abou ...200616738107
studies on bacterial phosphatases: the phosphatases of aerobacter aerogenes, alcaligenes faecalis and bacillus subtilis. 193816746654
evaluation of the duopath legionella lateral flow assay for identification of legionella pneumophila and legionella species culture isolates.duopath legionella (merck kgaa, darmstadt, germany) is a new immunochromatographic assay for the simultaneous identification of cultured l. pneumophila and legionella species other than l. pneumophila. in tests of 89 l. pneumophila strains and 87 legionella strains other than l. pneumophila representing 41 different species, duopath and a widely used latex agglutination assay detected l. pneumophila with 100% and 98% accuracy, respectively, whereas the percentages differed significantly for othe ...200616751575
biology of pseudomonas stutzeri.pseudomonas stutzeri is a nonfluorescent denitrifying bacterium widely distributed in the environment, and it has also been isolated as an opportunistic pathogen from humans. over the past 15 years, much progress has been made in elucidating the taxonomy of this diverse taxonomical group, demonstrating the clonality of its populations. the species has received much attention because of its particular metabolic properties: it has been proposed as a model organism for denitrification studies; many ...200616760312
immobilization of permeabilized whole cell penicillin g acylase from alcaligenes faecalis using pore matrix crosslinked with glutaraldehyde.the activity of penicillin g acylase from alcaligenes faecalis increased 7.5-fold when cells were permeabilized with 0.3% (w/v) ctab. the treated cells were entrapped by polyvinyl alcohol crosslinked with boric acid, and crosslinked with 2% (v/v) glutaraldehyde to increase the stability. the conversion yield of penicillin g to 6-aminopenicillanic acid was 75% by immobilized system in batch reaction. no activity was lost after 15 cycles and about 65% enzyme activity was retained at the end of the ...200616799762
evaluation of pyrrolidonyl arylamidase for the identification of nonfermenting gram-negative evaluate the activity of pyrrolidonyl arylamidase (pyr) for the differentiation and identification of nonfermenting gram negative rods (nfgnr), 293 isolates were tested. a 24 h culture of each test organism was prepared. from this a 108-109 cfu/ml suspension was added to 0.25 ml of sterile physiologic solution. a pyr disk was then added and the test was incubated for 30 minutes at 35-37 degrees c, at environmental atmosphere. reading was done by adding 1 drop of cinnamaldehyde reagent. strain ...200716822636
quantitative detection of the nosz gene, encoding nitrous oxide reductase, and comparison of the abundances of 16s rrna, narg, nirk, and nosz genes in soils.nitrous oxide (n2o) is an important greenhouse gas in the troposphere controlling ozone concentration in the stratosphere through nitric oxide production. in order to quantify bacteria capable of n2o reduction, we developed a sybr green quantitative real-time pcr assay targeting the nosz gene encoding the catalytic subunit of the nitrous oxide reductase. two independent sets of nosz primers flanking the nosz fragment previously used in diversity studies were designed and tested (k. kloos, a. mer ...200616885263
piggery wastewater treatment using alcaligenes faecalis strain no. 4 with heterotrophic nitrification and aerobic denitrification.alcaligenes faecalis strain no. 4, which has heterotrophic nitrification and aerobic denitrification abilities, was used to treat actual piggery wastewater containing high-strength ammonium under aerobic conditions. in a continuous experiment using a solids-free wastewater (sfw) mixed with feces, almost all of the 2000 nh4+ -n mg/l and 12,000 cod mg/l in the wastewater was removed and the ammonium removal rate was approximately 30 mg-n/l/h, which was 5-10 times higher than the rates achieved by ...200616893560
effect of ph, temperature and substrate on n2o, no and co2 production by alcaligenes faecalis study the effect of ph, temperature and substrate on the magnitude of n(2)o and no production by heterotrophic nitrifiers.200616907816
fluorescence in situ hybridization for rapid identification of achromobacter xylosoxidans and alcaligenes faecalis recovered from cystic fibrosis patients.achromobacter xylosoxidans is frequently isolated from the respiratory secretions of cystic fibrosis (cf) patients, but identification with biochemical tests is unreliable. we describe fluorescence in situ hybridization assays for the rapid identification of achromobacter xylosoxidans and alcaligenes faecalis. both assays showed high sensitivities and high specificities with a collection of 155 nonfermenters from cf patients.200616954289
effects of mutations in the substrate-binding domain of poly[(r)-3-hydroxybutyrate] (phb) depolymerase from ralstonia pickettii t1 on phb degradation.poly[(r)-3-hydroxybutyrate] (phb) depolymerase from ralstonia pickettii t1 (phaz(rpit1)) adsorbs to denatured phb (dphb) via its substrate-binding domain (sbd) to enhance dphb degradation. to evaluate the amino acid residues participating in dphb adsorption, phaz(rpit1) was subjected to a high-throughput screening system consisting of pcr-mediated random mutagenesis targeted to the sbd gene and a plate assay to estimate the effects of mutations in the sbd on dphb degradation by phaz(rpit1). gene ...200616963553
probing the unusual oxidation/reduction behavior of paracoccus pantotrophus cytochrome cd1 nitrite reductase by replacing a switchable methionine heme iron ligand with histidine.a m106h variant, where m106 is a c-type heme iron axial ligand, of cytochrome cd(1) nitrite reductase is an inactive protein in vivo. expression of the holoprotein in paracoccus pantotrophus required generation of nitric oxide during cell growth through simultaneous expression of an exogenous copper nitrite reductase from alcaligenes faecalis. in the absence of the latter protein, only a semi-apo form of m106h cytochrome cd(1) was formed. thus it was demonstrated that expression of the chromosom ...200616964982
the efficacy of postenucleation saline wash and the effect of different antimicrobial agents on microbial contamination of donor evaluate the efficacy of postenucleation saline wash and the effect of different antimicrobial agents on the microbial contamination of donor eyes.200616974130
two-center collaborative evaluation of performance of the bd phoenix automated microbiology system for identification and antimicrobial susceptibility testing of gram-negative bacteria.the performance of the bd phoenix automated microbiology system (bd diagnostic systems, sparks, md) was assessed for identification (id) and antimicrobial susceptibility testing (ast) of the majority of clinically encountered bacterial isolates in a european collaborative two-center trial. a total of 494 bacterial isolates including various species of the enterobacteriaceae and 110 nonfermentative gram-negative bacteria were investigated: of these, 385 were single patient isolates, and 109 were ...200617005752
crystal structure of an electron transfer complex between aromatic amine dehydrogenase and azurin from alcaligenes faecalis.the crystal structure of an electron transfer complex of aromatic amine dehydrogenase (aadh) and azurin is presented. electrons are transferred from the tryptophan tryptophylquinone (ttq) cofactor of aadh to the type i copper of the cupredoxin azurin. this structure is compared with the complex of the ttq-containing methylamine dehydrogenase (madh) and the cupredoxin amicyanin. despite significant similarities between the two quinoproteins and the two cupredoxins, each is specific for its respec ...200617087503
site-directed mutagenesis indicates an important role of cysteines 76 and 181 in the catalysis of hydantoin racemase from sinorhizobium meliloti.hydantoin racemase enzyme plays a crucial role in the reaction cascade known as "hydantoinase process." in conjunction with a stereoselective hydantoinase and a stereospecific carbamoylase, it allows the total conversion from d,l-5-monosubstituted hydantoins, with a low rate of racemization, to optically pure d- or l-amino acids. residues cys76 and cys181 belonging to hydantoin racemase from sinorhizobium meliloti (smehyua) have been proved to be involved in catalysis. here, we report biophysica ...200617132860
a robotic dna purification protocol and real-time pcr for the detection of enterobacter sakazakii in powdered infant formulae.enterobacter sakazakii is the causative agent of rare but severe food-borne infections associated with meningitis, necrotizing enterocolitis and sepsis in infants. rehydrated powdered infant formulae have been implicated as the source of infection in several outbreaks and sporadic cases. in this work, a real time fluorescence resonance energy transfer pcr assay incorporating an internal amplification control (iac) was developed for the specific detection of e. sakazakii in foods. performance of ...200617166252
erythromycin resistance-conferring plasmid prsb105, isolated from a sewage treatment plant, harbors a new macrolide resistance determinant, an integron-containing tn402-like element, and a large region of unknown function.the erythromycin resistance plasmid prsb105 was previously isolated from an activated sludge bacterial community of a municipal wastewater treatment plant. compilation of the complete prsb105 nucleotide sequence revealed that the plasmid is 57,137 bp in size and has a mean g+c content of 56.66 mol%. the prsb105 backbone is composed of two different replication and/or partitioning modules and a functional mobilization region encoding the mobilization genes mobcde and mobba. the first replicon (re ...200717261525
improvement in ammonium removal efficiency in wastewater treatment by mixed culture of alcaligenes faecalis no. 4 and improve ammonium removal efficiency in wastewater treatment, a mixed culture of alcaligenes faecalis no. 4 and its mutant l1, both of which have heterotrophic nitrification and aerobic denitrification abilities, was performed. in a batch culture, no. 4 has a higher denitrification ability than l1, but its ammonium removal rate was lower. in a mixed continuous culture in the ammonium loading range of 750 to 3500 mg-n/l/d, the average ammonium removal rate and the average denitrification ratio ...200717298903
decolorisation and detoxification of direct blue-15 by a bacterial consortium.studies were carried out on decolorisation and biotransformation of the dye direct blue-15 into 3,3'-dimethoxybenzidine (o'-dianisidine) and a sulphonated derivative by a five-member bacterial consortium. chromatographic studies revealed further complete biodegradation of 3,3'-dimethoxybenzidine coupled with release of ammonia, but the recalcitrant sulphonated derivative persisted. the microorganisms identified in the mixed consortium by 16s rdna sequence analysis were alcaligenes faecalis, sphi ...200717321737
characterization of sodc, a periplasmic superoxide dismutase from burkholderia cenocepacia.burkholderia cenocepacia is a gram-negative, non-spore-forming bacillus and a member of the burkholderia cepacia complex. b. cenocepacia can survive intracellularly in phagocytic cells and can produce at least one superoxide dismutase (sod). the inability of o2- to cross the cytoplasmic membrane, coupled with the periplasmic location of cu,znsods, suggests that periplasmic sods protect bacteria from superoxide that has an exogenous origin (for example, when cells are faced with reactive oxygen i ...200717325048
beta-1,4-glucanase-like protein from the cyanobacterium synechocystis pcc6803 is a beta-1,3-1,4-glucanase and functions in salt stress the present study, we characterized the gene (cyanobase accession number slr0897) designated ssglc encoding a beta-1,4-glucanase-like protein (ssglc) from synechocystis pcc6803. the deduced amino acid sequence for ssglc showed a high degree of similarity to sequences of gh (glycoside hydrolase) family 9 beta-1,4-glucanases (cellulases) from various sources. surprisingly, the recombinant protein obtained from the escherichia coli expression system was able to hydrolyse barley beta-glucan and l ...200717331074
structure and function of a hexameric copper-containing nitrite reductase.dissimilatory nitrite reductase (nir) is a key enzyme in denitrification, catalyzing the first step that leads to gaseous products (no, n(2)o, and n(2)). we have determined the crystal structure of a cu-containing nir from a methylotrophic denitrifying bacterium, hyphomicrobium denitrificans, at 2.2-a resolution. the overall structure of this h. denitrificans nir reveals a trigonal prism-shaped molecule in which a monomer consisting of 447 residues and three cu atoms is organized into a unique h ...200717360521
[reaction of microorganisms to the digestive fluid of the earthworms].the reaction of soil bacteria and fungi to the digestive fluid of the earthworm aporrectodea caliginosa was studied. the fluid was obtained by centrifugation of the native enzymes of the digestive tract. the inhibition of growth of certain bacteria, spores, and fungal hyphae under the effect of extracts from the anterior and middle sections of the digestive tract of a. caliginosa was discovered for the first time. in bacteria, microcolony formation was inhibited as early as 20-30 s after the app ...200717410875
bacterial decolorization of acid orange 7 in the presence of ionic and non-ionic surfactants.the effects of the non-ionic surfactant triton x-100, the cationic surfactant cetyltri-methylammonium bromide (ctab) and the anionic surfactant sodium n-lauroyl sarcosinate (sls) on the decolorization of the reaction medium containing the monoazo dye acid orange 7 (ao7) by alcaligenes faecalis and rhodococcus erythropolis were studied. it was found that the surfactants influenced in different ways the rate of decolorization. at all concentrations tested the non-ionic surfactant triton x-100 decr ...200717425112
a tale of two oxidation states: bacterial colonization of arsenic-rich environments.microbial biotransformations have a major impact on contamination by toxic elements, which threatens public health in developing and industrial countries. finding a means of preserving natural environments-including ground and surface waters-from arsenic constitutes a major challenge facing modern society. although this metalloid is ubiquitous on earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized. in-depth exploration of the genome of the beta ...200717432936
biochemical characterization of per-2 and genetic environment of blaper-2.per-2 was the first detected and the second most prevalent extended-spectrum beta-lactamase in clinical pathogens isolated in argentina and was also reported only in other south american countries. citrobacter freundii 33587 was isolated in 1999 in buenos aires and was resistant to all tested beta-lactams except cephamycins and carbapenems. the strain produced both plasmid-borne tem-1 and per-2 (pi 5.4), which could be transferred by conjugation. by pcr screening, thermal asymmetric interlaced p ...200717438050
evaluation of the colorimetric vitek 2 card for identification of gram-negative nonfermentative rods: comparison to 16s rrna gene sequencing.ninety strains of a collection of well-identified clinical isolates of gram-negative nonfermentative rods collected over a period of 5 years were evaluated using the new colorimetric vitek 2 card. the vitek 2 colorimetric system identified 53 (59%) of the isolates to the species level and 9 (10%) to the genus level; 28 (31%) isolates were misidentified. an algorithm combining the colorimetric vitek 2 card and 16s rrna gene sequencing for adequate identification of gram-negative nonfermentative r ...200717507509
posttraumatic endophthalmitis due to a rare pathogen, alcaligenes faecalis. 200717508059
nucleotide sequence of plasmid pcnb1 from comamonas strain cnb-1 reveals novel genetic organization and evolution for 4-chloronitrobenzene degradation.the nucleotide sequence of a new plasmid pcnb1 from comamonas sp. strain cnb-1 that degrades 4-chloronitrobenzene (4cnb) was determined. pcnb1 belongs to the incp-1beta group and is 91,181 bp in length. a total of 95 open reading frames appear to be involved in (i) the replication, maintenance, and transfer of pcnb1; (ii) resistance to arsenate and chromate; and (iii) the degradation of 4cnb. the 4cnb degradative genes and arsenate resistance genes were located on an extraordinarily large transp ...200717526790
formation of amyloid fibrils via longitudinal growth of oligomers.mature amyloid fibrils are believed to be formed by the lateral association of discrete structural units designated as protofibrils, but this lateral association of protofibrils has never been directly observed. we have recently characterized a thioesterase from alcaligenes faecalis, which was shown to exist as homomeric oligomers with an average diameter of 21.6 nm consisting of 22 kda subunits in predominantly beta-sheet structure. in this study, we have shown that upon incubation in a 75% eth ...200717536835
n-acetyl-d-glucosamine-6-phosphate deacetylase: substrate activation via a single divalent metal ion.naga is a member of the amidohydrolase superfamily and catalyzes the deacetylation of n-acetyl-d-glucosamine-6-phosphate. the catalytic mechanism of this enzyme was addressed by the characterization of the catalytic properties of metal-substituted derivatives of naga from escherichia coli with a variety of substrate analogues. the reaction mechanism is of interest since naga from bacterial sources is found with either one or two divalent metal ions in the active site. this observation indicates ...200717567047
protein film voltammetry of copper-containing nitrite reductase reveals reversible inactivation.the cu-containing nitrite reductase from alcaligenes faecalis s-6 catalyzes the one-electron reduction of nitrite to nitric oxide (no). electrons enter the enzyme at the so-called type-1 cu site and are then transferred internally to the catalytic type-2 cu site. protein film voltammetry experiments were carried out to obtain detailed information about the catalytic cycle. the homotrimeric structure of the enzyme is reflected in a distribution of the heterogeneous electron-transfer rates around ...200717579406
biodegradation of phenol at high initial concentration by alcaligenes faecalis.strain alcaligenes faecalis was isolated and identified as a member of the genus alcaligenes by using biolog and 16s rdna sequence analysis. the phenol biodegradation tests showed that the phenol-degrading potential of a. faecalis related greatly to the different physiological phases of inoculum. the maximum phenol degradation occurred at the late phase of the exponential growth stages, where 1600 mg l(-1) phenol was completely degraded within 76 h. a. faecalis secreted and accumulated a vast qu ...200717597295
comparison of hand-held test kits, immunofluorescence microscopy, enzyme-linked immunosorbent assay, and flow cytometric analysis for rapid presumptive identification of yersinia in-house immunochromatographic test, plague biothreat alert test strips, abicap columns, enzyme-linked immunosorbent assay, flow cytometry, and immunofluorescence microscopy were compared for the detection of the fraction 1 capsular antigen of yersinia pestis, using spiked buffer and clinical specimens. hand-held test kits proved to be excellent benchtop tools.200717652472
temperature effect on bacterial azo bond reduction kinetics: an arrhenius plot analysis.studied was the effect of temperature in the range 12-46 degrees c on the rate of bacterial decolorization of the mono-azo dye acid orange 7 by alcaligenes faecalis 6132 and rhodococcus erythropolis 24. with both strains the raise of temperature led to a corresponding raise of decolorization rate better manifested by r. erythropolis. the analysis of the arrhenius plot revealed a break near the middle of the temperature range. the regression analysis showed practically complete identity of the ob ...200817653820
investigation of the redox centres of periplasmic selenate reductase from thauera selenatis by epr spectroscopy.periplasmic ser (selenate reductase) from thauera selenatis is classified as a member of the tat (twin-arginine translocase)-translocated (type ii) molybdoenzymes and comprises three subunits each containing redox cofactors. variable-temperature x-band epr spectra of the purified ser complex showed features attributable to centres [3fe-4s]1+, [4fe-4s]1+, mo(v) and haem-b. epr-monitored redox-potentiometric titration of the serabc complex (sera-serb-serc, a hetero-trimetric complex of alphabetaga ...200717688424
influence of different carboxy-terminal mutations on the substrate-, reaction- and enantiospecificity of the arylacetonitrilase from pseudomonas fluorescens ebc191.different members of the nitrilase superfamily (d-carbamoylases, nit-fhit proteins, amidases, cyanide dihydratases and nitrilases) were compared by multiple sequence alignments and a long carboxy-terminal extension (about 50 amino acids) identified in all nitrilases and cyanide dihydratases which was not present in other members of the nitrilase superfamily. the function of this c-terminal part was experimentally analysed in the arylacetonitrilase of pseudomonas fluorescens ebc191 by the constru ...200717693456
control of microorganisms and reduction of biogenic amines in chicken breast and thigh by irradiation and organic acids.the effect of irradiation or organic acid treatment of raw chicken breast and thigh meat to control inoculated microorganisms and the production of biogenic amines (ba) was studied. bacillus cereus, enterobacter cloacae, and alcaligenes faecalis were selected and inoculated into raw ground chicken breast and thigh meat at approximately 10(7) cfu/g. the samples were irradiated at 0, 0.5, 1, and 2 kgy or mixed with a 0.2 m solution of acetic, citric, or lactic acid (1 ml for 10 g of meat sample) f ...200717704395
genomic analysis reveals widespread occurrence of new classes of copper nitrite reductases.recently, the structure of a cu-containing nitrite reductase (nir) from hyphomicrobium denitrificans (hdnir) has been reported, establishing the existence of a new family of cu-nir where an additional type 1 cu (t1cu) containing cupredoxin domain is located at the n-terminus (nojiri et al. in proc. natl. acad. sci. usa 104:4315-4320, 2007). hdnir retains the well-characterised coupled t1cu-type 2 cu (t2cu) core, where the t2cu catalytic site is also built utilising ligands from neighbouring mono ...200717712582
reconstitution of a branch of the manduca sexta prophenoloxidase activation cascade in vitro: snake-like hemolymph proteinase 21 (hp21) cleaved by hp14 activates prophenoloxidase-activating proteinase-2 precursor.upon wounding or infection, a serine proteinase cascade in insect hemolymph leads to prophenoloxidase (propo) activation and melanization, a defense response against invading microbes. in the tobacco hornworm manduca sexta, this response is initiated via hemolymph proteinase 14 (hp14), a mosaic protein that interacts with bacterial peptidoglycan or fungal beta-1,3-glucan to autoactivate. in this paper, we report the expression, purification, and functional analysis of m. sexta hp21 precursor, an ...200717785189
convergent evolution of a new arsenic binding site in the arsr/smtb family of metalloregulators.acidithiobacillus ferrooxidans has an arsenic resistance operon that is controlled by an as(iii)-responsive transcriptional repressor, afarsr, a member of the arsr/smtb family of metalloregulators. afarsr lacks the as(iii) binding site of the arsrs from plasmid r773 and escherichia coli, which have a cys(32)-val-cys(34)-asp-leu-cys(37) sequence in the dna binding site. in contrast, it has three cysteine residues, cys(95), cys(96), and cys(102), that are not present in the r773 and e. coli arsrs. ...200717897948
stable copper-nitrosyl formation by nitrite reductase in either oxidation state.nitrite reductase (nir) is an enzyme that uses type 1 and type 2 copper sites to reduce nitrite to nitric oxide during bacterial denitrification. a copper-nitrosyl intermediate is a proposed, yet poorly characterized feature of the nir catalytic cycle. this intermediate is formally described as cu(i)-no+ and is proposed to be formed at the type 2 copper site after nitrite binding and electron transfer from the type 1 copper site. in this study, copper-nitrosyl complexes were formed by prolonged ...200717924665
antibacterial activity of guava (psidium guajava l.) and neem (azadirachta indica a. juss.) extracts against foodborne pathogens and spoilage bacteria.the antibacterial activity of guava (psidium guajava) and neem (azadirachta indica) extracts against 21 strains of foodborne pathogens were determined--listeria monocytogenes (five strains), staphylococcus aureus (four strains), escherichia coli o157:h7 (six strains), salmonella enteritidis (four strains), vibrio parahaemolyticus, and bacillus cereus, and five food spoilage bacteria: pseudomonas aeroginosa, p. putida, alcaligenes faecalis, and aeromonas hydrophila (two strains). guava and neem e ...200718041957
the autodisplay story, from discovery to biotechnical and biomedical applications.among the pathways used by gram-negative bacteria for protein secretion, the autotransporter pathway represents a solution of impressive simplicity. proteins are transported, independent of their nature as recombinant or native passengers, as long as the coding nucleotide sequence is inserted in frame between those of an n-terminal signal peptide and a c-terminal domain, referred to as the beta-barrel of the outer membrane translocation unit. the immunoglobulin a1 (iga1) protease from neisseria ...200718063719
high incidence of plant growth-stimulating bacteria associated with the rhizosphere of wheat grown on salinated soil in uzbekistan.soil salinization is increasing steadily in many parts of the world and causes major problems for plant productivity. under these stress conditions, root-associated beneficial bacteria can help improve plant growth and nutrition. in this study, salt-tolerant bacteria from the rhizosphere of uzbek wheat with potentially beneficial traits were isolated and characterized. eight strains which initially positively affect the growth of wheat plants in vitro were investigated in detail. all eight strai ...200818211262
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