Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| osmoregulated periplasmic glucans of erwinia chrysanthemi. | we report the initial characterization of the osmoregulated periplasmic glucans (opgs) of erwinia chrysanthemi. opgs are intrinsic components of the bacterial envelope necessary to the pathogenicity of this phytopathogenic enterobacterium (f. page, s. altabe, n. hugouvieux-cotte-pattat, j.-m. lacroix, j. robert-baudouy and j.-p. bohin, j. bacteriol. 183:0000-0000, 2001 [companion in this issue]). opgs were isolated by trichloracetic acid treatment and gel permeation chromatography. the synthesis ... | 2001 | 11325941 |
| osmoregulated periplasmic glucan synthesis is required for erwinia chrysanthemi pathogenicity. | erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants. osmoregulated periplasmic glucans (opgs) are intrinsic components of the gram-negative bacterial envelope. we cloned the opggh operon of e. chrysanthemi, encoding proteins involved in the glucose backbone synthesis of opgs, by complementation of the homologous locus mdogh of escherichia coli. opgg and opgh show a high level of similarity with mdog and mdoh, respectively, and mutations in ... | 2001 | 11325942 |
| effects of mutations in the pseudomonas putida miaa gene: regulation of the trpe and trpgdc operons in p. putida by attenuation. | tn5 insertion mutants defective in regulation of the pseudomonas putida trpe and trpgdc operons by tryptophan were found to contain insertions in the p. putida miaa gene, whose product (in escherichia coli) modifies trna(trp) and is required for attenuation. nucleotide sequences upstream of trpe and trpg encode putative leader peptides similar in sequence to leader peptides found in other bacterial species, and the phenotypes of the mutants strongly suggest that transcription of these operons is ... | 2001 | 11325956 |
| tomato ve disease resistance genes encode cell surface-like receptors. | in tomato, ve is implicated in race-specific resistance to infection by verticillium species causing crop disease. characterization of the ve locus involved positional cloning and isolation of two closely linked inverted genes. expression of individual ve genes in susceptible potato plants conferred resistance to an aggressive race 1 isolate of verticillium albo-atrum. the deduced primary structure of ve1 and ve2 included a hydrophobic n-terminal signal peptide, leucine-rich repeats containing 2 ... | 2001 | 11331751 |
| the leucine-rich repeat domain can determine effective interaction between rps2 and other host factors in arabidopsis rps2-mediated disease resistance. | like many other plant disease resistance genes, arabidopsis thaliana rps2 encodes a product with nucleotide-binding site (nbs) and leucine-rich repeat (lrr) domains. this study explored the hypothesized interaction of rps2 with other host factors that may be required for perception of pseudomonas syringae pathogens that express avrrpt2 and/or for the subsequent induction of plant defense responses. crosses between arabidopsis ecotypes col-0 (resistant) and po-1 (susceptible) revealed segregation ... | 2001 | 11333251 |
| overexpression of the tobacco tsi1 gene encoding an erebp/ap2-type transcription factor enhances resistance against pathogen attack and osmotic stress in tobacco. | using mrna differential display analysis, we isolated a salt-induced transcript that showed a significant sequence homology with an erebp/ap2 dna binding motif from oilseed rape plants. with this cdna fragment as a probe, cdna clone tsi1 (for tobacco stress-induced gene1) was isolated from a tobacco cdna library. rna gel blot analysis indicated that transcripts homologous with tsi1 were induced not only in nacl-treated leaves but also in leaves treated with ethephon or salicylic acid. transient ... | 2001 | 11340180 |
| a harpin binding site in tobacco plasma membranes mediates activation of the pathogenesis-related gene hin1 independent of extracellular calcium but dependent on mitogen-activated protein kinase activity. | harpin from the bean halo-blight pathogen pseudomonas syringae pv phaseolicola (harpin(psph)) elicits the hypersensitive response and the accumulation of pathogenesis-related gene transcripts in the nonhost plant tobacco. here, we report the characterization of a nonproteinaceous binding site for harpin(psph) in tobacco plasma membranes, which is assumed to mediate the activation of plant defense responses in a receptor-like manner. binding of 125i-harpin(psph) to tobacco microsomal membranes (d ... | 2001 | 11340183 |
| both the extracellular leucine-rich repeat domain and the kinase activity of fsl2 are required for flagellin binding and signaling in arabidopsis. | in arabidopsis, activation of defense responses by flagellin is triggered by the specific recognition of the most conserved domain of flagellin, represented by the peptide flg22, in a process involving the fls2 gene, which encodes a leucine-rich repeat serine/threonine protein kinase. we show here that the two fls2 mutant alleles, fls2-24 and fls2-17, which were shown previously to confer insensitivity to flg22, also cause impaired flagellin binding. these features are rescued when a functional ... | 2001 | 11340188 |
| structural and functional analysis of the phosphonoacetate hydrolase (phna) gene region in pseudomonas fluorescens 23f. | the pseudomonas fluorescens 23f phosphonoacetate hydrolase gene (phna) encodes a novel carbon-phosphorus bond cleavage enzyme whose expression is independent of the phosphate status of the cell. analysis of the regions adjacent to the phosphonoacetate hydrolase structural gene (phna) indicated the presence of five open reading frames (orfs). these include one (phnr) whose putative product shows high levels of homology to the lysr family of positive transcriptional regulators. its presence was sh ... | 2001 | 11344133 |
| characterization and mutational analysis of three allelic lsc genes encoding levansucrase in pseudomonas syringae. | in the plant pathogen pseudomonas syringae pv. glycinea pg4180 and other bacterial species, synthesis of the exopolysaccharide levan is catalyzed by the extracellular enzyme levansucrase. the results of southern blotting and pcr analysis indicated the presence of three levansucrase-encoding genes in strain pg4180: lsca, lscb, and lscc. in this study, lscb and lscc were cloned from a genomic library of strain pg4180. sequence analysis of the two lsc genes showed that they were virtually identical ... | 2001 | 11344135 |
| suppression of the ribosomal l2 gene reveals a novel mechanism for stress adaptation in soybean. | pseudomonas syringae pv. glycinea bacteria or zoospores of the fungus phytophthora sojae were used to trigger a hypersensitive reaction (hr) in cell cultures of soybean (glycine max [l.] merr. cv. williams 82). during a screen for genes that show an altered expression as a response to dying neighbour cells we have identified a gene fragment that is specifically but transiently down-regulated in an hr. the corresponding cdna codes for the ribosomal protein l2 (rpl2) of 80s ribosomes, which is ess ... | 2001 | 11346953 |
| development of immunomagnetic separation technique for isolation of pseudomonas syringae pv. phaseolicola. | immunomagnetic separation technique was developed for specific detection and selective isolation of pseudomonas syringae pv. phaseolicola, the agent of halo-blight disease of beans. whole-cell and exopolysaccharide fraction of the bacterium was used for polyclonal antibody production in rabbits. high specificity of the antisera was determined in agglutination reactions. the optimum immunocapture time for both antisera was determined as 1 h by using 1/nl cfu (i.e. 10(6) cfu per ml). no significan ... | 2000 | 11347253 |
| regulation of alternative oxidase activity in six wild monocotyledonous species. an in vivo study at the whole root level. | the activity of the alternative pathway is affected by a number of factors, including the level and reduction state of the alternative oxidase (aox) protein, and the reduction state of the ubiquinone pool. to investigate the significance of these factors for the rate of alternative respiration in vivo, we studied root respiration of six wild monocotyledonous grass species that were grown under identical controlled conditions. the activity of the alternative pathway was determined using the oxyge ... | 2001 | 11351100 |
| effects of synthetic cecropin analogs on in vitro growth of acholeplasma laidlawii. | four synthetic peptides (peptidyl mims; demeter biotechnologies, inc.) were evaluated for their in vitro activity against acholeplasma laidlawii. fifty percent effective concentration values ranged from 1 to 15 microm. three of these compounds are more lethal than cecropin b against a. laidlawii. | 2001 | 11353647 |
| the arabidopsis pbs1 resistance gene encodes a member of a novel protein kinase subfamily. | specific recognition of pseudomonas syringae strains that express the avirulence gene avrpphb requires two genes in arabidopsis, rps5 and pbs1. previous work has shown that rps5 encodes a member of the nucleotide binding site-leucine rich repeat class of plant disease resistance genes. here we report that pbs1 encodes a putative serine-threonine kinase. southern blot analysis revealed that the pbs1-1 allele contained a deletion of the 3' end of the pbs1 open reading frame. dna sequence analysis ... | 2001 | 11359614 |
| the luxm homologue vanm from vibrio anguillarum directs the synthesis of n-(3-hydroxyhexanoyl)homoserine lactone and n-hexanoylhomoserine lactone. | vibrio anguillarum, which causes terminal hemorrhagic septicemia in fish, was previously shown to possess a luxri-type quorum-sensing system (vanri) and to produce n-(3-oxodecanoyl)homoserine lactone (3-oxo-c10-hsl). however, a vani null mutant still activated n-acylhomoserine lactone (ahl) biosensors, indicating the presence of an additional quorum-sensing circuit in v. anguillarum. in this study, we have characterized this second system. using high-pressure liquid chromatography in conjunction ... | 2001 | 11371516 |
| ralstonia solanacearum needs motility for invasive virulence on tomato. | ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. by examining bacteria from the xylem vessels of infected plants, we found that r. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. to determine the role of pathogen motility in this disease, we cloned, charac ... | 2001 | 11371523 |
| regulation of rpos gene expression in pseudomonas: involvement of a tetr family regulator. | the rpos gene encodes the sigma factor which was identified in several gram-negative bacteria as a central regulator during stationary phase. rpos gene regulation is known to respond to cell density, showing higher expression in stationary phase. for pseudomonas aeruginosa, it has been demonstrated that the cell-density-dependent regulation response known as quorum sensing interacts with this regulatory response. using the rpos promoter of p. putida, we identified a genomic tn5 insertion mutant ... | 2001 | 11371535 |
| role of a ferredoxin gene cotranscribed with the nifhdk operon in n(2) fixation and nitrogenase "switch-off" of azoarcus sp. strain bh72. | the endophytic diazotroph azoarcus sp. strain bh72 is capable of infecting rice roots and of expressing the nitrogenase (nif) genes there. in order to study the genetic background for nitrogen fixation in strain bh72, the structural genes of nitrogenase (nifhdk) were cloned and sequenced. the sequence analysis revealed an unusual gene organization: downstream of nifhdk, a ferredoxin gene (fdxn; 59% amino acid sequence identity to r. capsulatus fdxn) and open reading frames showing 52 and 36% ami ... | 2001 | 11371540 |
| flagellum-independent surface migration of vibrio cholerae and escherichia coli. | surface translocation has been described in a large variety of microorganisms, including some gram-negative enteric bacteria. here, we describe the novel observation of the flagellum-independent migration of vibrio cholerae and escherichia coli on semisolid surfaces with remarkable speeds. important aspects of this motility are the form of inoculation, the medium composition, and the use of agarose rather than agar. mutations in several known regulatory or surface structure proteins, such as tox ... | 2001 | 11371543 |
| toxic effects of linear alkylbenzene sulfonate on metabolic activity, growth rate, and microcolony formation of nitrosomonas and nitrosospira strains. | strong inhibitory effects of the anionic surfactant linear alkylbenzene sulfonate (las) on four strains of autotrophic ammonia-oxidizing bacteria (aob) are reported. two nitrosospira strains were considerably more sensitive to las than two nitrosomonas strains were. interestingly, the two nitrosospira strains showed a weak capacity to remove las from the medium. this could not be attributed to adsorption or any other known physical or chemical process, suggesting that biodegradation of las took ... | 2001 | 11375155 |
| involvement of nitrate reductase and pyoverdine in competitiveness of pseudomonas fluorescens strain c7r12 in soil. | involvement of nitrate reductase and pyoverdine in the competitiveness of the biocontrol strain pseudomonas fluorescens c7r12 was determined, under gnotobiotic conditions, in two soil compartments (bulk and rhizosphere soil), with the soil being kept at two different values of matric potential (-1 and -10 kpa). three mutants affected in the synthesis of either the nitrate reductase (nar(-)), the pyoverdine (pvd(-)), or both (nar(-) pvd(-)) were used. the nar(-) and nar(-) pvd(-) mutants were obt ... | 2001 | 11375173 |
| comparison of endotoxin exposure assessment by bioaerosol impinger and filter-sampling methods. | environmental assessment data collected in two prior occupational hygiene studies of swine barns and sawmills allowed the comparison of concurrent, triplicate, side-by-side endotoxin measurements using air sampling filters and bioaerosol impingers. endotoxin concentrations in impinger solutions and filter eluates were assayed using the limulus amebocyte lysate assay. in sawmills, impinger sampling yielded significantly higher endotoxin concentration measurements and lower variances than filter s ... | 2001 | 11375194 |
| survival of escherichia coli o157:h7 atcc 43895 in a model apple juice medium with different concentrations of proline and caffeic acid. | the effects of proline and caffeic acid on the survival of shiga toxin-producing escherichia coli (stec) o157:h7 strain atcc 43895 in a model apple juice medium were studied. it is hypothesized that the inhibitory effect of caffeic acid may explain why almost all outbreaks of stec o157:h7 infections linked to apple juice or cider have occurred in october or november. | 2001 | 11375209 |
| [processes of plant colonization by methylobacterium strains and some bacterial properties ]. | the pink-pigmented facultative methylotrophic bacteria (ppfmb) of the genus methylobacterium are indespensible inhabitants of the plant phyllosphere. using maize zea mays as a model, the ways of plant colonization by ppfmb and some properties of the latter that might be beneficial to plants were studied. a marked strain, methylobacterium mesophilicum apr-8 (pulb113), was generated to facilitate the detection of the methylotrophic bacteria inoculated into the soil or applied to the maize leaves. ... | 2001 | 11386061 |
| identification and expression of the pseudomonas syringae pv. aptata hrpz(psa) gene which encodes an harpin elicitor. | a sequence homologous to an internal fragment 0.75 kb bstxi of the pseudomonas syringae pv. syringae hrpz gene was identified in pseudomonas syringae pv. aptata ncppb 2664, the causal agent of bacterial blight in sugar beet, lettuce and other plants. and in e. coli dh10b (pccp1069) containing the p. syringae pv. aptata hrp gene cluster. pcr with oligonucleotides, based on the hrpz(pss) gene and used as primers with the total genomic dna of p. syringae pv. aptata, amplified a 1 kb fragment that h ... | 2001 | 11392485 |
| the agrobacterium tumefaciens rnd homolog is required for trar-mediated quorum-dependent activation of ti plasmid tra gene expression. | conjugal transfer of agrobacterium tumefaciens ti plasmids is regulated by quorum sensing via trar and its cognate autoinducer, n-(3-oxo-octanoyl)-l-homoserine lactone. we isolated four tn5-induced mutants of a. tumefaciens c58 deficient in trar-mediated activation of tra genes on ptic58deltaaccr. these mutations also affected the growth of the bacterium but had no detectable influence on the expression of two tester gene systems that are not regulated by quorum sensing. in all four mutants tn5 ... | 2001 | 11395455 |
| visualization of secreted hrp and avr proteins along the hrp pilus during type iii secretion in erwinia amylovora and pseudomonas syringae. | pili are required for protein and/or dna transfer from bacteria to recipient plant or bacterial cells, based on genetic evidence. however, it has never been shown directly that the effector proteins or dna are localized along or inside the pili in situ. failure to visualize an association of effector proteins/dna with pili is the central issue in the debate regarding the exact function of pili in protein and dna transfer. in this study, a newly developed in situ immunogold labelling procedure en ... | 2001 | 11401717 |
| complete dna sequence of yersinia enterocolitica serotype 0:8 low-calcium-response plasmid reveals a new virulence plasmid-associated replicon. | the complete nucleotide sequence and organization of the yersinia enterocolitica serotype 0:8 low-calcium-response (lcr) plasmid, pyve8081, were determined. the 67,720-bp plasmid encoded all the genes known to be part of the lcr stimulon except for ylpa. eight of 13 intact open reading frames of unknown function identified in pyve8081 had homologues in yersinia pestis plasmid pcd1 or in y. enterocolitica serotype 0:9 plasmid pyve227. a region of approximately 17 kbp showed no dna identity to pcd ... | 2001 | 11402007 |
| beta-aminobutyric acid-induced protection of arabidopsis against the necrotrophic fungus botrytis cinerea. | the non-protein amino acid beta-aminobutyric acid (baba) protects numerous plants against various pathogens. protection of arabidopsis plants against virulent pathogens involves the potentiation of pathogen-specific defense responses. to extend the analysis of the mode of action of baba to necrotrophs we evaluated the effect of this chemical on arabidopsis plants infected with the gray mold fungus botrytis cinerea. baba-treated arabidopsis were found to be less sensitive to two different strains ... | 2001 | 11402183 |
| jasmonate-dependent induction of indole glucosinolates in arabidopsis by culture filtrates of the nonspecific pathogen erwinia carotovora. | elicitors from the plant pathogen erwinia carotovora trigger coordinate induction of the tryptophan (trp) biosynthesis pathway and trp oxidizing genes in arabidopsis. to elucidate the biological role of such pathogen-induced activation we characterized the production of secondary defense metabolites such as camalexin and indole glucosinolates derived from precursors of this pathway. elicitor induction was followed by a specific increase in 3-indolylmethylglucosinolate (igs) content, but only a b ... | 2001 | 11402212 |
| characterization of the lipopolysaccharide and structure of the o-specific polysaccharide of the bacterium pseudomonas syringae pv. atrofaciens imv 948. | lipopolysaccharide (lps) was isolated from the phytopathogenic bacterium pseudomonas syringae pv. atrofaciens imv 948 by mild extraction of the microbial cells with saline, and the properties, composition, and structure of the lps were studied. the lps showed low toxicity in d- galactosamine-sensitized mice and low biological activity in plants. structural components of lps--lipid a, core oligosaccharide, and o-specific polysaccharide (ops)--were obtained by mild acid degradation and characteriz ... | 2001 | 11403642 |
| analysis of the enzymatic domains in the modular portion of the coronafacic acid polyketide synthase. | coronafacic acid (cfa) is the polyketide component of coronatine (cor), a phytotoxin produced by the plant pathogen pseudomonas syringae. the cfa polyketide synthase (pks) consists of two open reading frames (orfs) that encode type i multifunctional proteins and several orfs that encode monofunctional proteins. sequence comparisons of the modular portions of the cfa pks with other prokaryotic, modular pkss elucidated the boundaries of the domains that are involved in the individual stages of pol ... | 2001 | 11404016 |
| broad-spectrum antimicrobial activity in vitro of the synthetic peptide d4e1. | broad-spectrum antimicrobial activity of a synthetic peptide, d4e1, is documented in this paper. d4e1 inhibited the growth of several fungal phytopathogens belonging to four classes-ascomycetes, basidiomycetes, deuteromycetes, and oomycetes, and two bacterial pathogens, pseudomonas syringae pv. tabaci and xanthomonas campestris pv. malvacearum race 18. the minimum inhibitory concentration (mic) of d4e1 required to completely inhibit the growth of all fungi studied ranged from 4.67 to 25 microm. ... | 2001 | 11409968 |
| the alkane hydroxylase gene of burkholderia cepacia rr10 is under catabolite repression control. | in many microorganisms the first step for alkane degradation is the terminal oxidation of the molecule by an alkane hydroxylase. we report the characterization of a gene coding for an alkane hydroxylase in a burkholderia cepacia strain isolated from an oil-contaminated site. the protein encoded showed similarity to other known or predicted bacterial alkane hydroxylases, although it clustered on a separate branch together with the predicted alkane hydroxylase of a mycobacterium tuberculosis strai ... | 2001 | 11418560 |
| trans-3-chloroacrylic acid dehalogenase from pseudomonas pavonaceae 170 shares structural and mechanistic similarities with 4-oxalocrotonate tautomerase. | the genes (caad1 and caad2) encoding the trans-3-chloroacrylic acid dehalogenase (caad) of the 1,3-dichloropropene-utilizing bacterium pseudomonas pavonaceae 170 were cloned and heterologously expressed in escherichia coli and pseudomonas sp. strain gj1. caad is a protein of 50 kda that is composed of alpha-subunits of 75 amino acid residues and beta-subunits of 70 residues. it catalyzes the hydrolytic cleavage of the beta-vinylic carbon-chlorine bond in trans-3-chloroacrylic acid with a turnove ... | 2001 | 11418568 |
| constitutive salicylic acid-dependent signaling in cpr1 and cpr6 mutants requires pad4. | salicylic acid (sa)-dependent signaling controls activation of a set of plant defense mechanisms that are important for resistance to a variety of microbial pathogens. many arabidopsis mutants that display altered sa-dependent signaling have been isolated. we used double mutant analysis to determine the relative positions of the pad4, cpr1, cpr5, cpr6, dnd1 and dnd2 mutations in the signal transduction network leading to sa-dependent activation of defense gene expression and disease resistance. ... | 2001 | 11439127 |
| resistance to pseudomonas syringae conferred by an arabidopsis thaliana coronatine-insensitive (coi1) mutation occurs through two distinct mechanisms. | a new allele of the coronatine-insensitive locus (coi1) was isolated in a screen for arabidopsis thaliana mutants with enhanced resistance to the bacterial pathogen pseudomonas syringae. this mutant, designated coi1-20, exhibits robust resistance to several p. syringae isolates but remains susceptible to the virulent pathogens erisyphe and cauliflower mosaic virus. resistance to p. syringae strain pstdc3000 in coi1-20 plants is correlated with hyperactivation of pr-1 expression and accumulation ... | 2001 | 11439137 |
| potential virulence role of the legionella pneumophila ptsp ortholog. | we previously identified the legionella pneumophila ptsp (phosphoenolpyruvate phosphotransferase) ortholog gene as a putative virulence factor in a study of signature-tagged mutagenesis using a guinea pig pneumonia model. in this study, we further defined the phenotypic properties of l. pneumophila ptsp and its complete sequence. the l. pneumophila ptsp was 2,295 bases in length. its deduced amino acid sequence had high similarity with ptsp orthologs of pseudomonas aeruginosa, azotobacter vinela ... | 2001 | 11447151 |
| evolutionary relationships among virulence-associated histidine kinases. | a strong relationship between virulence-associated sensor histidine kinases of fungi and those in streptomyces coelicolor was observed, and phylogenetic analysis suggested that bacterium-to-eukaryote horizontal gene transfer had occurred between ancestors of these organisms. phylogenetic analysis also identified a group of histidine kinases orthologous to the streptomyces proteins that includes pseudomonas aeruginosa gacs. we provide evidence that gacs is important for swarming motility, lipase ... | 2001 | 11447209 |
| evidence for an important role of wrky dna binding proteins in the regulation of npr1 gene expression. | the arabidopsis npr1 gene is a positive regulator of inducible plant disease resistance. expression of npr1 is induced by pathogen infection or treatment with defense-inducing compounds such as salicylic acid (sa). transgenic plants overexpressing npr1 exhibit enhanced resistance to a broad spectrum of microbial pathogens, whereas plants underexpressing the gene are more susceptible to pathogen infection. these results suggest that regulation of npr1 gene expression is important for the activati ... | 2001 | 11449049 |
| persistence and translocation of a benzothiadiazole derivative in tomato plants in relation to systemic acquired resistance against pseudomonas syringae pv tomato. | a reproducible and accurate procedure, based on hplc analysis, has been developed to determine simultaneously acibenzolar-s-methyl (cga 245 704) and its acid derivative (cga 210 007) in tomato leaves. the limit of detection and quantification of the method are 0.015 and 0.15 mg litre-1 for cga 245 704 and 0.030 and 0.30 mg litre-1 for cga 210 007. in tomato plants treated with 250 microm cga 245 704, it was found that the inducer rapidly translocates from treated leaves (cotyledons, 1st and 2nd) ... | 2001 | 11455656 |
| the ice nucleation temperature determines the primary drying rate of lyophilization for samples frozen on a temperature-controlled shelf. | the objective of this study was to determine the influence of ice nucleation temperature on the primary drying rate during lyophilization for samples in vials that were frozen on a lyophilizer shelf. aqueous solutions of 10% (w/v) hydroxyethyl starch were frozen in vials with externally mounted thermocouples and then partially lyophilized to determine the primary drying rate. low- and high-particulate-containing samples, ice-nucleating additives silver iodide and pseudomonas syringae, and other ... | 2001 | 11458335 |
| oxidation of phenolate siderophores by the multicopper oxidase encoded by the escherichia coli yack gene. | a gene (yack) encoding a putative multicopper oxidase (mco) was cloned from escherichia coli, and the expressed enzyme was demonstrated to exhibit phenoloxidase and ferroxidase activities. the purified protein contained six copper atoms per polypeptide chain and displayed optical and electron paramagnetic resonance (epr) spectra consistent with the presence of type 1, type 2, and type 3 copper centers. the strong optical a(610) (e(610) = 10,890 m(-1) cm(-1)) and copper stoichiometry were taken a ... | 2001 | 11466290 |
| crystallization and preliminary x-ray analysis of clade i catalases from pseudomonas syringae and listeria seeligeri. | haem-containing catalases are homotetrameric molecules that degrade hydrogen peroxide. phylogenetically, the haem-containing catalases can be grouped into three main lines or clades. the crystal structures of seven catalases have been determined, all from clades ii and iii. in order to obtain a structure of an enzyme from clade i, which includes all plant, algae and some bacterial enzymes, two bacterial catalases, catf from pseudomonas syringae and kat from listeria seeligeri, have been crystall ... | 2001 | 11468413 |
| quantitative analysis of bacterial gene expression by using the gusa reporter gene system. | an azospirillum brasilense sp7 strain containing a plasmid-borne translational cytn-gusa fusion was grown in a continuous culture to quantitatively evaluate the influence of extracellular signals (such as o(2)) on expression of the cytnoqp operon. the dissolved oxygen concentration was shifted at regular time intervals before the steady state was reached. the measured beta-glucuronidase activity was used to monitor cytn gene expression. however, as the beta-glucuronidase activity in the experime ... | 2001 | 11472903 |
| carbon limitation induces sigma(s)-dependent gene expression in pseudomonas fluorescens in soil. | recent studies employing reporter gene technology indicate that the availabilities of the major nutrients nitrogen, phosphate, and iron to pseudomonas are not severely limited in bulk soil. indirect evidence has pointed to carbon limitation as a severe nutritional stress in this environment. we show that a plasmid (pgm115)-borne transcriptional fusion between the sigma(s)-dependent escherichia coli promoter p(fic) and lacz functions as a reliable reporter for carbon availability in pseudomonas f ... | 2001 | 11472905 |
| assessment of the genetic diversity among strains of xanthomonas cynarae by randomly amplified polymorphic dna analysis and development of specific characterized amplified regions for the rapid identification of x. cynarae. | the randomly amplified polymorphic dna (rapd) method was used to investigate the genetic diversity in xanthomonas cynarae, which causes bacterial bract spot disease of artichoke. this rapd analysis was also intended to identify molecular markers characteristic of this species, in order to develop pcr-based markers which can be used to detect this pathogenic bacterium in artichoke fields. among the 340 rapd primers tested, 40 were selected on their ability to produce reproducible and reliable fin ... | 2001 | 11472907 |
| use of an intergenic region in pseudomonas syringae pv. syringae b728a for site-directed genomic marking of bacterial strains for field experiments. | to construct differentially-marked derivatives of our model wild-type strain, pseudomonas syringae pv. syringae b728a (a causal agent of bacterial brown spot disease in snap bean plants), for field experiments, we selected a site in the gacs-cysm intergenic region for site-directed insertion of antibiotic resistance marker cassettes. in each of three field experiments, population sizes of the site-directed chromosomally marked b728a derivatives in association with snap bean plants were not signi ... | 2001 | 11472957 |
| isolation and in vivo and in vitro antifungal activity of phenylacetic acid and sodium phenylacetate from streptomyces humidus. | the antifungal substances sh-1 and sh-2 were isolated from streptomyces humidus strain s5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. sh-1 and sh-2 completely inhibited the growth of pythium ultimum, phytophthora capsici, rhizoctonia solani, saccharomyces cerevisiae, and pseudomonas syringae p ... | 2001 | 11472958 |
| activation of salicylic acid-induced protein kinase, a mitogen-activated protein kinase, induces multiple defense responses in tobacco. | the activation of mitogen-activated protein kinases (mapks) is one of the earliest responses in plants challenged by avirulent pathogens or cells treated with pathogen-derived elicitors. expression of a constitutively active mapk kinase, ntmek2(dd), in tobacco induces the expression of defense genes and hypersensitive response-like cell death, which are preceded by the activation of two endogenous mapks, salicylic acid-induced protein kinase (sipk) and wounding-induced protein kinase (wipk). how ... | 2001 | 11487699 |
| hsr203 antisense suppression in tobacco accelerates development of hypersensitive cell death. | activation of the tobacco gene hsr203 is rapid, highly localized, specific for incompatible plant-pathogen interactions, and strongly correlated with programmed cell death occurring in response to diverse pathogens. functional characterization of hsr203 gene product has shown that hsr203 is a serine hydrolase that displays esterase activity. we show here that transgenic tobacco plants deficient in hsr203 protein exhibit an accelerated hypersensitive response when inoculated with an avirulent str ... | 2001 | 11489189 |
| halohydrin dehalogenases are structurally and mechanistically related to short-chain dehydrogenases/reductases. | halohydrin dehalogenases, also known as haloalcohol dehalogenases or halohydrin hydrogen-halide lyases, catalyze the nucleophilic displacement of a halogen by a vicinal hydroxyl function in halohydrins to yield epoxides. three novel bacterial genes encoding halohydrin dehalogenases were cloned and expressed in escherichia coli, and the enzymes were shown to display remarkable differences in substrate specificity. the halohydrin dehalogenase of agrobacterium radiobacter strain ad1, designated hhe ... | 2001 | 11489858 |
| absence of all components of the flagellar export and synthesis machinery differentially alters virulence of salmonella enterica serovar typhimurium in models of typhoid fever, survival in macrophages, tissue culture invasiveness, and calf enterocolitis. | in this study, we constructed an flhd (the master flagellar regulator gene) mutant of salmonella enterica serovar typhimurium and compared the virulence of the strain to that of the wild-type strain in a series of assays that included the mouse model of typhoid fever, the mouse macrophage survival assay, an intestinal epithelial cell adherence and invasion assay, and the calf model of enterocolitis. we found that the flhd mutant was more virulent than its parent in the mouse and displayed slight ... | 2001 | 11500437 |
| numeric simulation of plant signaling networks. | plants have evolved an intricate signaling apparatus that integrates relevant information and allows an optimal response to environmental conditions. for instance, the coordination of defense responses against pathogens involves sophisticated molecular detection and communication systems. multiple protection strategies may be deployed differentially by the plant according to the nature of the invading organism. these responses are also influenced by the environment, metabolism, and developmental ... | 2001 | 11500542 |
| harpin induces activation of the arabidopsis mitogen-activated protein kinases atmpk4 and atmpk6. | mitogen-activated protein kinases (mapks) are key enzymes that mediate adaptive responses to various abiotic and biotic stresses, including pathogen challenge. the proteinaceous bacterial elicitor harpin (secreted by pseudomonas syringae pv syringae) activates two mapks in suspension cultures of arabidopsis var. landsberg erecta. in this study, we show that harpin and exogenous hydrogen peroxide (h(2)o(2)) activate myelin basic protein kinases in arabidopsis leaves. using anti-atmpk4 and anti-at ... | 2001 | 11500556 |
| expression of 35s::pto globally activates defense-related genes in tomato plants. | the tomato (lycopersicon esculentum) resistance gene pto confers resistance to the bacterial pathogen pseudomonas syringae pv tomato carrying the avirulent gene avrpto. overexpressing pto under the control of the cauliflower mosaic virus 35s promoter constitutively activates defense responses in the absence of pathogen infection and nonspecifically enhances disease resistance. to elucidate the mechanisms underlying this resistance, we isolated cdnas corresponding to transcripts that accumulated ... | 2001 | 11500562 |
| cloning and characterization of a coronatine-regulated tyrosine aminotransferase from arabidopsis. | in plants, the phytotoxin coronatine, which is an analog of the octadecanoids 12-oxo-phytodienoic acid and/or jasmonic acid, gives rise to a number of physiological responses similar to those of octadecanoids. to further elucidate the physiological role of these compounds, the differential rna display technique was used to isolate a number of novel octadecanoid-inducible genes expressed in coronatine-treated arabidopsis. among these, a cdna clone was identified that was similar to known tyrosine ... | 2001 | 11500565 |
| n-terminal fatty acid substitution increases the leishmanicidal activity of ca(1-7)m(2-9), a cecropin-melittin hybrid peptide. | in order to improve the leishmanicidal activity of the synthetic cecropin a-melittin hybrid peptide ca(1-7)m(2-9) (kwklfkkigavlkvl-nh(2)), a systematic study of its acylation with saturated linear fatty acids was carried out. acylation of the n(epsilon)-7 lysine residue led to a drastic decrease in leishmanicidal activity, whereas acylation at lysine 1, in either the alpha or the epsilon nh(2) group, increased up to 3 times the activity of the peptide against promastigotes and increased up to 15 ... | 2001 | 11502512 |
| hypervalent iodine compounds as potent antibacterial agents against ice nucleation active (ina) pseudomonas syringae. | twenty-three hypervalent iodine compounds belonging to aryliodonium salts, 1, aryliodonium ylides, 2, and (diacyloxyiodo)arenes, 3, were tested for their antibacterial activities against ice nucleation active (ina) pseudomonas syringae, and the mic and ec(50) values were determined. all of the compounds examined caused a dose-dependent decrease in bacterial growth rates. aryliodonium salts, especially those with electron-withdrawing groups, exhibit higher antibacterial activities with mic = 8-16 ... | 2001 | 11513659 |
| rapid identification and differentiation of the soft rot erwinias by 16s-23s intergenic transcribed spacer-pcr and restriction fragment length polymorphism analyses. | current identification methods for the soft rot erwinias are both imprecise and time-consuming. we have used the 16s-23s rrna intergenic transcribed spacer (its) to aid in their identification. analysis by its-pcr and its-restriction fragment length polymorphism was found to be a simple, precise, and rapid method compared to current molecular and phenotypic techniques. the its was amplified from erwinia and other genera using universal pcr primers. after pcr, the banding patterns generated allow ... | 2001 | 11526007 |
| gly gene cloning and expression and purification of glycinecin a, a bacteriocin produced by xanthomonas campestris pv. glycines 8ra. | glycinecin a, a bacteriocin produced by xanthomonas campestris pv. glycines, inhibits the growth of x. campestris pv. vesicatoria. we have cloned and expressed the genes encoding glycinecin a in escherichia coli. recombinant glycinecin a was purified from cell extracts by ammonium sulfate precipitation followed by chromatography on q-sepharose, mono q (ion exchange), and size exclusion columns. purified glycinecin a is composed of two polypeptides, is active over a wide ph range (6 to 9), and is ... | 2001 | 11526012 |
| a second quorum-sensing system regulates cell surface properties but not phenazine antibiotic production in pseudomonas aureofaciens. | the root-associated biological control bacterium pseudomonas aureofaciens 30-84 produces a range of exoproducts, including protease and phenazines. phenazine antibiotic biosynthesis by phzxyfabcd is regulated in part by the phzr-phzi quorum-sensing system. mutants defective in phzr or phzi produce very low levels of phenazines but wild-type levels of exoprotease. in the present study, a second genomic region of strain 30-84 was identified that, when present in trans, increased beta-galactosidase ... | 2001 | 11526037 |
| characterization by 16s rrna sequence analysis of pseudomonads causing blotch disease of cultivated agaricus bisporus. | bacterial blotch of agaricus bisporus has typically been identified as being caused by either pseudomonas tolaasii (brown blotch) or pseudomonas gingeri (ginger blotch). to address the relatedness of pseudomonads able to induce blotch, a pilot study was initiated in which pseudomonads were selectively isolated from mushroom farms throughout new zealand. thirty-three pseudomonad isolates were identified as being capable of causing different degrees of discoloration (separable into nine categories ... | 2001 | 11526038 |
| the arabidopsis aberrant growth and death2 mutant shows resistance to pseudomonas syringae and reveals a role for npr1 in suppressing hypersensitive cell death. | a novel arabidopsis mutant has been identified with constitutive expression of gst1-gus using plants with a pathogen-responsive reporter transgene containing the beta-glucuronidase (gus) coding region driven by the gst1 promoter. the recessive mutant, called agd2 (aberrant growth and death2), has salicylic acid (sa)-dependent increased resistance to virulent and avirulent strains of the bacterial pathogen pseudomonas syringae, elevated sa levels, a low level of spontaneous cell death, callose de ... | 2001 | 11532166 |
| enhancer-binding proteins hrpr and hrps interact to regulate hrp-encoded type iii protein secretion in pseudomonas syringae strains. | in pseudomonas syringae strains, the hrp-hrc pathogenicity island consists of an hrpl-dependent regulon that encodes a type iii protein translocation complex and translocated effector proteins required for pathogenesis. hrpr and hrps function as positive regulatory factors for the hrpl promoter, but their mechanism of action has not been established. both hrpr and hrps are structurally related to enhancer-binding proteins, but they lack receiver domains and do not appear to require a cognate pro ... | 2001 | 11544221 |
| complete nucleotide sequence and organization of the atrazine catabolic plasmid padp-1 from pseudomonas sp. strain adp. | the complete 108,845-nucleotide sequence of catabolic plasmid padp-1 from pseudomonas sp. strain adp was determined. plasmid padp-1 was previously shown to encode atza, atzb, and atzc, which catalyze the sequential hydrolytic removal of s-triazine ring substituents from the herbicide atrazine to yield cyanuric acid. computational analyses indicated that padp-1 encodes 104 putative open reading frames (orfs), which are predicted to function in catabolism, transposition, and plasmid maintenance, t ... | 2001 | 11544232 |
| arabidopsis research 2001. | 2001 | 11549757 | |
| epidemic population structure of pseudomonas aeruginosa: evidence for a clone that is pathogenic to the eye and that has a distinct combination of virulence factors. | the genetic structure of a population of pseudomonas aeruginosa, isolated from patients with keratitis, endophthalmitis, and contact lens-associated red eye, contact lens storage cases, urine, ear, blood, lungs, wounds, feces, and the environment was determined by multilocus enzyme electrophoresis. the presence and characteristics of virulence factors were determined by restriction fragment length polymorphism analysis with dna probes for lasa, lasb, apra, exos, exot, exou, and ctx and by zymogr ... | 2001 | 11553572 |
| n-acylphosphatidylethanolamine accumulation in potato cells upon energy shortage caused by anoxia or respiratory inhibitors. | a minor phospholipid was isolated from potato (solanum tuberosum l. cv bintje) cells, chromatographically purified, and identified by electrospray ionization mass spectrometry as n-acylphosphatidylethanolamine (nape). the nape level was low in unstressed cells (13 +/- 4 nmol g fresh weight(-1)). according to acyl chain length, only 16/18/18 species (group ii) and 18/18/18 species (group iii) were present. nape increased up to 13-fold in anoxia-stressed cells, but only when free fatty acids (ffas ... | 2001 | 11553752 |
| salicylic acid and ethylene pathways are differentially activated in melon cotyledons by active or heat-denatured cellulase from trichoderma longibrachiatum. | infiltration of cellulase (ec 3.2.1.4) from trichoderma longibrachiatum into melon (cucumis melo) cotyledons induced several key defense mechanisms and hypersensitive reaction-like symptoms. an oxidative burst was observed 3 hours after treatment and was followed by activation of ethylene and salicylic acid (sa) signaling pathways leading to marked induction of peroxidase and chitinase activities. the treatment of cotyledons by heat-denatured cellulase also led to some induction of peroxidase an ... | 2001 | 11553761 |
| nitrate-induced genes in tomato roots. array analysis reveals novel genes that may play a role in nitrogen nutrition. | a subtractive tomato (lycopersicon esculentum) root cdna library enriched in genes up-regulated by changes in plant mineral status was screened with labeled mrna from roots of both nitrate-induced and mineral nutrient-deficient (-nitrogen [n], -phosphorus, -potassium [k], -sulfur, -magnesium, -calcium, -iron, -zinc, and -copper) tomato plants. a subset of cdnas was selected from this library based on mineral nutrient-related changes in expression. additional cdnas were selected from a second min ... | 2001 | 11553762 |
| type iii secretion in plant growth-promoting pseudomonas fluorescens sbw25. | in vivo expression technology (ivet) analysis of rhizosphere-induced genes in the plant growth-promoting rhizobacterium (pgpr) pseudomonas fluorescens sbw25 identified a homologue of the type iii secretion system (ttss) gene hrcc. the hrcc homologue resides within a 20-kb gene cluster that resembles the type iii (hrp) gene cluster of pseudomonas syringae. the type iii (rsp) gene cluster in p. fluorescens sbw25 is flanked by a homologue of the p. syringae ttss-secreted protein avre. p. fluorescen ... | 2001 | 11555282 |
| genetic characterization of pseudomonas 'nzi7'--a novel pathogen that results in a brown blotch disease of agaricus bisporus. | to characterize a novel pseudomonad isolate capable of causing brown blotch disease of agaricus bisporus. | 2001 | 11556905 |
| [comparative characteristics of lipopolysaccharides of various pseudomonas fluorescens strains (biovar i)]. | from the biomass of five pseudomonas fluorescens biovar i strains, including the p. fluorescens type strain imv 4125 (atcc 13525), lipopolysaccharides (lps) were isolated (by extraction with a phenol-water mixture followed by repeated ultracentrifugation), as well as individual structural components of the lps macromolecule: lipid a, the core oligosaccharide, and o-specific polysaccharide (o-ps). 3-hydroxydecanoic, 2-hydroxydodecanoic, 3-hydroxydodecanoic, dodecanoic, hexadecanoic, octadecanoic, ... | 2001 | 11558277 |
| lignification induced by pseudomonads harboring avirulent genes on arabidopsis. | the responses of arabidopsis thaliana ecotypes to the bacterial pathogen pseudomonas syringae pv. maculicola 4326 (psm4326) harboring cloned avirulence genes avrb and avrrpt2 from p. syringae pv. glycinea were examined. psm4326 containing avirulent genes, avrb and avrrpt2 induced lignification and peroxidase activities in the bacteria infiltrated leaves of col-o only and not in mt-o, bla-2 and po-1. however, arabidopsis ecotypes infiltrated with psm4326 harboring with and without avirulent genes ... | 2001 | 11561727 |
| escherichia coli fadr positively regulates transcription of the fabb fatty acid biosynthetic gene. | in escherichia coli expression of the genes of fatty acid degradation (fad) is negatively regulated at the transcriptional level by fadr protein. in contrast the unsaturated fatty acid biosynthetic gene, faba, is positively regulated by fadr. we report that fabb, a second unsaturated fatty acid biosynthetic gene, is also positively regulated by fadr. genomic array studies that compared global transcriptional differences between wild-type and fadr-null mutant strains, as well as in cultures of ea ... | 2001 | 11566998 |
| ssebcd proteins are secreted by the type iii secretion system of salmonella pathogenicity island 2 and function as a translocon. | the type iii secretion system encoded by salmonella pathogenicity island 2 (spi2) is required for systemic infections and intracellular accumulation of salmonella enterica. this system is induced by intracellular salmonella and subsequently transfers effector proteins into the host cell. growth conditions either inducing expression of the type iii secretion system or the secretion of substrate proteins were defined. here we report the identification of a set of substrate proteins consisting of s ... | 2001 | 11567004 |
| direct interaction between the arabidopsis disease resistance signaling proteins, eds1 and pad4. | the arabidopsis eds1 and pad4 genes encode lipase-like proteins that function in resistance (r) gene-mediated and basal plant disease resistance. phenotypic analysis of eds1 and pad4 null mutants shows that eds1 and pad4 are required for resistance conditioned by the same spectrum of r genes but fulfil distinct roles within the defence pathway. eds1 is essential for elaboration of the plant hypersensitive response, whereas eds1 and pad4 are both required for accumulation of the plant defence-pot ... | 2001 | 11574472 |
| cdna-aflp analysis unravels a genome-wide hrpg-regulon in the plant pathogen xanthomonas campestris pv. vesicatoria. | the hrp type iii protein secretion system is essential for pathogenicity of the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria. expression of the hrp gene cluster is controlled by hrpg, a two-component response regulator, and hrpx, an arac-type transcriptional activator. using the cdna-aflp technique, 30 hrpg-induced (hgi) and five hrpg-repressed (hgr) cdna fragments were identified, defining a large hrpg-regulon in x. campestris pv. vesicatoria. expression of most genes in ... | 2001 | 11580833 |
| pseudomonas aeruginosa pao1 kills caenorhabditis elegans by cyanide poisoning. | in this report we describe experiments to investigate a simple virulence model in which pseudomonas aeruginosa pao1 rapidly paralyzes and kills the nematode caenorhabditis elegans. our results imply that hydrogen cyanide is the sole or primary toxic factor produced by p. aeruginosa that is responsible for killing of the nematode. four lines of evidence support this conclusion. first, a transposon insertion mutation in a gene encoding a subunit of hydrogen cyanide synthase (hcnc) eliminated nemat ... | 2001 | 11591663 |
| bacterial two-hybrid analysis of interactions between region 4 of the sigma(70) subunit of rna polymerase and the transcriptional regulators rsd from escherichia coli and algq from pseudomonas aeruginosa. | a number of transcriptional regulators mediate their effects through direct contact with the sigma(70) subunit of escherichia coli rna polymerase (rnap). in particular, several regulators have been shown to contact a c-terminal portion of sigma(70) that harbors conserved region 4. this region of sigma contains a putative helix-turn-helix dna-binding motif that contacts the -35 element of sigma(70)-dependent promoters directly. here we report the use of a recently developed bacterial two-hybrid s ... | 2001 | 11591686 |
| mammalian bax-induced plant cell death can be down-regulated by overexpression of arabidopsis bax inhibitor-1 (atbi-1). | we recently isolated the atbi-1 (arabidopsis bax inhibitor-1) gene, the expression of which suppressed bax-induced cell death in yeast. to determine whether the same is true in the plant system, transgenic arabidopsis plants overexpressing bax protein under a dexamethasone (dex)-inducible promoter were generated. on dex treatment, such transgenic plants exhibited marked cell death at the whole-plant level, cell shrinkage, membranous destruction, and other apoptotic phenotypes. transgenic bax pla ... | 2001 | 11593047 |
| plant biology 2001. | 2001 | 11595794 | |
| the disease resistance signaling components eds1 and pad4 are essential regulators of the cell death pathway controlled by lsd1 in arabidopsis. | specific recognition of pathogens is mediated by plant disease resistance (r) genes and translated into a successful defense response. the extent of associated hypersensitive cell death varies from none to an area encompassing cells surrounding an infection site, depending on the r gene activated. we constructed double mutants in arabidopsis between positive regulators of r function and a negative regulator of cell death, lsd1, to address whether genes required for normal r function also regulat ... | 2001 | 11595797 |
| a humidity-sensitive arabidopsis copine mutant exhibits precocious cell death and increased disease resistance. | the copines are a newly identified class of calcium-dependent, phospholipid binding proteins that are present in a wide range of organisms, including paramecium, plants, caenorhabditis elegans, mouse, and human. however, the biological functions of the copines are unknown. here, we describe a humidity-sensitive copine mutant in arabidopsis. under nonpermissive, low-humidity conditions, the cpn1-1 mutant displayed aberrant regulation of cell death that included a lesion mimic phenotype and an acc ... | 2001 | 11595798 |
| the esat-6 gene cluster of mycobacterium tuberculosis and other high g+c gram-positive bacteria. | the genome of mycobacterium tuberculosis h37rv has five copies of a cluster of genes known as the esat-6 loci. these clusters contain members of the cfp-10 (lhp) and esat-6 (esat-6) gene families (encoding secreted t-cell antigens that lack detectable secretion signals) as well as genes encoding secreted, cell-wall-associated subtilisin-like serine proteases, putative abc transporters, atp-binding proteins and other membrane-associated proteins. these membrane-associated and energy-providing pro ... | 2001 | 11597336 |
| families of restriction enzymes: an analysis prompted by molecular and genetic data for type id restriction and modification systems. | current genetic and molecular evidence places all the known type i restriction and modification systems of escherichia coli and salmonella enterica into one of four discrete families: type ia, ib, ic or id. stysbli is the founder member of the id family. similarities of coding sequences have identified restriction systems in e.coli and klebsiella pneumoniae as probable members of the type id family. we present complementation tests that confirm the allocation of ecor9i and kpnai to the id family ... | 2001 | 11600708 |
| comparison of polymerase subunits from double-stranded rna bacteriophages. | the family cystoviridae comprises several bacteriophages with double-stranded rna (dsrna) genomes. we have previously purified the catalytic polymerase subunit (pol) of one of the cystoviridae members, bacteriophage phi6, and shown that the protein can catalyze rna synthesis in vitro. in this reaction, both bacteriophage-specific and heterologous rnas can serve as templates, but those containing 3' termini from the phi6 minus strands are favored. this provides a molecular basis for the observati ... | 2001 | 11602748 |
| activation of an eds1-mediated r-gene pathway in the snc1 mutant leads to constitutive, npr1-independent pathogen resistance. | the arabidopsis npr1 protein is an essential regulatory component of systemic acquired resistance (sar). mutations in the npr1 gene completely block the induction of sar by signals such as salicylic acid (sa). an arabidopsis mutant, snc1 (suppressor of npr1-1, constitutive 1), was isolated in a screen for suppressors of npr1-1. in the npr1-1 background, the snc1 mutation resulted in constitutive resistance to pseudomonas syringae maculicola es4326 and peronospora parasitica noco2. high levels of ... | 2001 | 11605952 |
| genetic organization of the pantoea stewartii subsp. stewartii hrp gene cluster and sequence analysis of the hrpa, hrpc, hrpn, and wtse operons. | the hrp/wts gene cluster of pantoea stewartii subsp. stewartii is required for pathogenicity on sweet corn and the ability to elicit a hypersensitive response (hr) in tobacco. site-directed transposon mutagenesis and nucleotide sequencing were used to identify hrp/wts genes within the left 20 kb of this cluster. seventeen open reading frames (orfs) comprise seven genetic complementation groups. these orfs share homology with hrp and dsp genes from erwinia amylovora, erwinia chrysanthemi, and pse ... | 2001 | 11605961 |
| signal interactions between nitric oxide and reactive oxygen intermediates in the plant hypersensitive disease resistance response. | nitric oxide (no) and reactive oxygen intermediates (rois) play key roles in the activation of disease resistance mechanisms both in animals and plants. in animals no cooperates with rois to kill tumor cells and for macrophage killing of bacteria. such cytotoxic events occur because unregulated no levels drive a diffusion-limited reaction with o(2)(-) to generate peroxynitrite (onoo(-)), a mediator of cellular injury in many biological systems. here we show that in soybean cells unregulated no p ... | 2001 | 11606758 |
| ndr1, a locus of arabidopsis thaliana that is required for disease resistance to both a bacterial and a fungal pathogen. | we have employed arabidopsis thaliana as a model host plant to genetically dissect the molecular pathways leading to disease resistance. a. thaliana accession col-0 is susceptible to the bacterial pathogen pseudomonas syringae pv. tomato strain dc3000 but resistant in a race-specific manner to dc3000 carrying any one of the cloned avirulence genes avrb, avrrpm1, avrrpt2, and avrpph3. fast-neutron-mutagenized col-0 m2 seed was screened to identify mutants susceptible to dc3000(avrb). disease assa ... | 1995 | 11607554 |
| frost resistance and pseudomonas. | a professor of biophysics and medical physics at the university of california, berkeley, comments on advances in developing frost-resistant crop plants, and on the objections that have halted or delayed field tests of these plants. jukes describes a proposed field trial by a biotechnology company, advanced genetic sciences (ags), of strawberry plants treated with the strains of common bacteria (pseudomonas syringae and pseudomonas fluorescens) from which the gene for the ice nucleation protein ... | 1986 | 11650712 |
| the global posttranscriptional regulator rsma modulates production of virulence determinants and n-acylhomoserine lactones in pseudomonas aeruginosa. | posttranscriptional control is known to contribute to the regulation of secondary metabolism and virulence determinants in certain gram-negative bacteria. here we report the isolation of a pseudomonas aeruginosa gene which encodes a global translational regulatory protein, rsma (regulator of secondary metabolites). overexpression of rsma resulted in a substantial reduction in the levels of extracellular products, including protease, elastase, and staphylolytic (lasa protease) activity as well as ... | 2001 | 11673439 |
| expression of borrelia burgdorferi ospc and dbpa is controlled by a rpon-rpos regulatory pathway. | rpos and rpon are two alternative sigma factors typically associated with general stress responses in bacteria. to date, there has been no experimental evidence that rpos and rpon can directly control the expression of one another. herein, using a combined strategy of gene disruption and genetic complementation targeting rpon and rpos in borrelia burgdorferi strain 297, we describe a regulatory network for b. burgdorferi. in this network, rpon controls the expression of rpos, which, in turn, gov ... | 2001 | 11675503 |
| dna sequence and mutational analysis of rhizobitoxine biosynthesis genes in bradyrhizobium elkanii. | we cloned and sequenced a cluster of genes involved in the biosynthesis of rhizobitoxine, a nodulation enhancer produced by bradyrhizobium elkanii. the nucleotide sequence of the cloned 28.4-kb dna region encompassing rtxa showed that several open reading frames (orfs) were located downstream of rtxa. a large-deletion mutant of b. elkanii, usda94 delta rtx::omega 1, which lacks rtxa, orf1 (rtxc), orf2, and orf3, did not produce rhizobitoxine, dihydrorhizobitoxine, or serinol. the broad-host-rang ... | 2001 | 11679318 |
| structural studies of the hrp secretion system: expression, purification, crystallization and preliminary x-ray analysis of the c-terminal domain of the hrcqb protein from pseudomonas syringae pv. phaseolicola. | the c-terminal domain of the hrcq(b) protein from the hrp secretion system of the plant pathogenic bacterium pseudomonas syringae pv. phaseolicola has been crystallized from mpd using the hanging-drop vapour-diffusion method. the crystals belong to space group p2(1), with unit-cell parameters a = 51.6, b = 27.3, c = 97.2 a and beta = 99.8 degrees. a complete native data set extending to 3.0 a resolution was collected from a single cryoprotected crystal. the crystal solvent content and calculatio ... | 2001 | 11679746 |
| crystallization and preliminary x-ray crystallographic analysis of native and selenomethionyl recombinant tabtoxin-resistance protein complexed with acetyl-coenzyme a. | tabtoxin-resistance protein (ttr), an acetyltransferase from pseudomonas syringae pv. tabaci, was overexpressed in eschericha coli m15 and the ttr fusion protein complexed with acetyl-coenzyme a (accoa) was purified and crystallized. diffraction data were collected to 3.0 a resolution in-house and the crystal was found to belong to space group p2(1), with unit-cell parameters a = 47.6, b = 66.6, c = 53.5 a, beta = 104.3 degrees. furthermore, a selenomethionine (semet) ttr fusion protein derivati ... | 2001 | 11679759 |
| dimethoxyphenol oxidase activity of different microbial blue multicopper proteins. | 2,6-dimethoxyphenol is a versatile substrate for pyricularia oryzae laccase, ppoa from marinomonas mediterranea, phenoxazinone synthase from streptomyces antibioticus and mammalian ceruloplasmin. in addition, in cellular extracts of microorganisms expressing other blue multicopper proteins with no enzymatic activity previously described, such as escherichia coli (copper resistance cueo), pseudomonas syringae and xanthomonas campestris (copper resistance copa), bacillus subtilis (sporulation prot ... | 2001 | 11682198 |