Publications

colonization of the arabidopsis rhizosphere by fluorescent pseudomonas spp. activates a root-specific, ethylene-responsive pr-5 gene in the vascular bundle.	plants of which the roots are colonized by selected strains of non-pathogenic, fluorescent pseudomonas spp. develop an enhanced defensive capacity against a broad spectrum of foliar pathogens. in arabidopsis thaliana, this rhizobacteria-induced systemic resistance (isr) functions independently of salicylic acid but requires responsiveness to jasmonic acid and ethylene. in contrast to pathogen-induced systemic acquired resistance (sar), isr is not associated with systemic changes in the expressio ...	2005	15988566
the map kinase substrate mks1 is a regulator of plant defense responses.	arabidopsis map kinase 4 (mpk4) functions as a regulator of pathogen defense responses, because it is required for both repression of salicylic acid (sa)-dependent resistance and for activation of jasmonate (ja)-dependent defense gene expression. to understand mpk4 signaling mechanisms, we used yeast two-hybrid screening to identify the mpk4 substrate mks1. analyses of transgenic plants and genome-wide transcript profiling indicated that mks1 is required for full sa-dependent resistance in mpk4 ...	2005	15990873
a surface modification strategy on silicon nitride for developing biosensors.	a surface modification strategy for the use of giant magnetoresistive materials in the detection of protein-protein interactions is developed. this modification strategy is based on silanization of semiconductive materials. a native silicon nitride surface was treated with concentrated hydrofluoric acid to improve surface homogeneity. nano-strip was used to oxidize silicon nitride to form a hydrophilic layer. aminopropyltriethoxysilane was subsequently used to functionalize the treated surfaces ...	2005	15993368
flavohaemoglobin hmpx from erwinia chrysanthemi confers nitrosative stress tolerance and affects the plant hypersensitive reaction by intercepting nitric oxide produced by the host.	host cells respond to infection by generating nitric oxide (no) as a cytotoxic weapon to facilitate killing of invading microbes. bacterial flavohaemoglobins are well-known scavengers of no and play a crucial role in protecting animal pathogens from nitrosative stress during infection. erwinia chrysanthemi, which causes macerating diseases in a wide variety of plants, possesses a flavohaemoglobin (hmpx) whose function in plant pathogens has remained unclear. here we show that hmpx consumes no an ...	2005	15998309
relative importance of bacteriocin-like genes in antagonism of xanthomonas perforans tomato race 3 to xanthomonas euvesicatoria tomato race 1 strains.	in a previous study, tomato race 3 (t3) strains of xanthomonas perforans became predominant in fields containing both x. euvesicatoria and x. perforans races t1 and t3, respectively. this apparent ability to take over fields led to the discovery that there are three bacteriocin-like compounds associated with t3 strains. t3 strain 91-118 produces at least three different bacteriocin-like compounds (bcn-a, bcn-b, and bcn-c) antagonistic toward t1 strains. we determined the relative importance of t ...	2005	16000765
changes in race-specific virulence in pseudomonas syringae pv. phaseolicola are associated with a chimeric transposable element and rare deletion events in a plasmid-borne pathogenicity island.	virulence for bean and soybean is determined by effector genes in a plasmid-borne pathogenicity island (pai) in race 7 strain 1449b of pseudomonas syringae pv. phaseolicola. one of the effector genes, avrpphf, confers either pathogenicity, virulence, or avirulence depending on the plant host and is absent from races 2, 3, 4, 6, and 8 of this pathogen. analysis of cosmid clones and comparison of dna sequences showed that the absence of avrpphf from strain 1448a is due to deletion of a continuous ...	2005	16000789
syrb2 in syringomycin e biosynthesis is a nonheme feii alpha-ketoglutarate- and o2-dependent halogenase.	the nine-residue lipodepsipeptide syringomycin e, elaborated as a phytotoxin by pseudomonas syringae pv. syringae b301d contains a 4-cl-l-thr-9 moiety where failure to chlorinate results in a 3-fold drop in biological activity. the proteins syrb1 and syrb2 encoded by the biosynthetic cluster are shown to act as a substrate and enzyme pair for syrb2-mediated chlorination of the aminoacyl-s-enzyme l-thr-s-syrb1. syrb2 is a member of the nonheme fe(ii) alpha-ketoglutarate-dependent enzyme superfami ...	2005	16002467
aggregates of resident bacteria facilitate survival of immigrant bacteria on leaf surfaces.	the fate of immigrant bacterial cells on leaves under stressful conditions was determined as a function of the anatomical features and the local spatial density of resident cells at their landing site. pantoea agglomerans 299r was established on bean leaves and the survival of immigrant cells of pseudomonas fluorescens a506 and pseudomonas syringae b728a, as well as p. agglomerans itself, was determined by epifluorescence microscopy following subsequent exposure of plants to desiccation stress. ...	2005	16003469
phylogenetic analysis of the phytochrome superfamily reveals distinct microbial subfamilies of photoreceptors.	phys (phytochromes) are a superfamily of photochromic photoreceptors that employ a bilin-type chromophore to sense red and far-red light. although originally thought to be restricted to plants, accumulating genetic and genomic analyses now indicate that they are also prevalent among micro-organisms. by a combination of phylogenetic and biochemical studies, we have expanded the phy superfamily and organized its members into distinct functional clades which include the phys (plant phys), bphps (ba ...	2005	16004604
activation of pepper basic pr-1 gene promoter during defense signaling to pathogen, abiotic and environmental stresses.	the basic pr-1 gene, cabpr1, accumulates in pepper leaf tissues during pathogen infection as well as after ethylene treatment. we isolated and functionally characterized the cabpr1 promoter region in tobacco leaves to identify the cis-acting regulatory sequences that are involved in cabpr1 gene expression. constructs harboring the 5'-serially deleted cabpr1 promoter, which was fused to the beta-glucuronidase (gus) gene, were evaluated for their promoter activity in the tobacco leaves. the cabpr1 ...	2005	16005163
the effect of a bacteriophage on diversification of the opportunistic bacterial pathogen, pseudomonas aeruginosa.	pseudomonas aeruginosa is an opportunistic human pathogen that colonizes the lungs of cystic fibrosis (cf) patients. cf lungs often contain a diverse range of p. aeruginosa phenotypes, some of which are likely to contribute to the persistence of infection, yet the causes of diversity are unclear. while the ecological heterogeneity of the lung environment and therapeutic regimes are probable factors, a role for parasitic bacteriophage cannot be ruled out. parasites have been implicated as a key e ...	2005	16006335
laser photoacoustic detection allows in planta detection of nitric oxide in tobacco following challenge with avirulent and virulent pseudomonas syringae pathovars.	we demonstrate the use of laser photoacoustic detection (lpad) as a highly sensitive method to detect in planta nitric oxide (()no) production from tobacco (nicotiana tabacum). lpad calibration against ()no gas demonstrated a linear relationship over 2 orders of magnitude with a detection threshold of <20 pmol h(-1) (1 part per billion volume [ppbv]). the specificity of the photoacoustic signal for ()no when adding gas or the ()no donor, sodium nitroprusside, on injection into plant leaves, ...	2005	16009999
[mechanism of antimutagenic activity of pseudomonas syringae lipopolysaccharides].	the antimutagenic activity of lipopolysaccharides of phytopathogenic bacteria,which are the agents of grain crops diseases, has been investigated using bacterial test-system with salmonella typhimurium. it has been established that the greatest antimutagen activity of pseudomonas syringae pv. atrofaciens and p. syringae pv. coronafaciens lipopolysaccharides was,if they and bichromate potassium be simultaneously added to cells test-strains of s. typhimurium. they decreased to a less degree quanti ...	2005	16018214
copc protein from pseudomonas syringae: intermolecular transfer of copper from both the copper(i) and copper(ii) sites.	the copc protein from pseudomonas syringae pathovar tomato is expressed as one of four proteins encoded by the operon copabcd that is responsible for copper resistance. it is a small soluble molecule (10.5 kda) with a beta-barrel structure and features two distinct copper binding sites, which are highly specific for cu(i) (k(d) > or = 10(-)(13)) and cu(ii) (k(d) approximately 10(-)(15)). these dissociation constants were estimated via ligand competition experiments monitored by electronic spectr ...	2005	16022515
involvement of algq in transcriptional regulation of pyoverdine genes in pseudomonas aeruginosa pao1.	in response to iron limitation, pseudomonas aeruginosa produces the fluorescent siderophore pyoverdine. transcription of pyoverdine biosynthetic (pvd) genes is driven by the iron starvation sigma factor pvds, which is negatively regulated by the fur-fe(ii) holorepressor. we studied the effect of algq, the escherichia coli rsd orthologue, on pyoverdine production by p. aeruginosa pao1. algq is a global regulatory protein which activates alginate, ppgpp, and inorganic polyphosphate synthesis throu ...	2005	16030202
a dna polymerase v homologue encoded by tol plasmid pww0 confers evolutionary fitness on pseudomonas putida under conditions of environmental stress.	plasmids in conjunction with other mobile elements such as transposons are major players in the genetic adaptation of bacteria in response to changes in environment. here we show that a large catabolic tol plasmid, pww0, from pseudomonas putida carries genes (rulab genes) encoding an error-prone dna polymerase pol v homologue which increase the survival of bacteria under conditions of accumulation of dna damage. a study of population dynamics in stationary phase revealed that the presence of pww ...	2005	16030214
use of suppression-subtractive hybridization to identify genes in the burkholderia cepacia complex that are unique to burkholderia cenocepacia.	we have previously shown differences in virulence between species of the burkholderia cepacia complex using the alfalfa infection model and the rat agar bead chronic infection model. burkholderia cenocepacia strains were more virulent in these two infection models than burkholderia multivorans and burkholderia stabilis strains. in order to identify genes that may account for the increased virulence of b. cenocepacia, suppression-subtractive hybridization was performed between b. cenocepacia k56- ...	2005	16030222
identification and characterization of the locus for diffuse adherence, which encodes a novel afimbrial adhesin found in atypical enteropathogenic escherichia coli.	the o26 serogroup of enteropathogenic escherichia coli (epec) is one of the serogroups most frequently implicated in infant diarrhea and is also common among enterohemorrhagic e. coli (ehec) strains. the most common o26 strains belong to epec/ehec serotype o26:h11 and are generally shiga toxin (stx) positive. stx-negative e. coli strains that are negative for the epec eaf plasmid and bundle-forming pilus (bfp) are classified as atypical epec. here, we report a novel adhesin present in an stx-neg ...	2005	16040988
antimicrobial activity of some ganoderma species from nigeria.	the crude n-hexane:diethyl ether, chloroform:acetone and methanol extracts of four species of ganoderma (ganoderma colossum (fr.) c. f. baker, g. resinaceum boud., g. lucidum (cf.) (curtis) p. karst. and g. boninense (cf.) pat.), from nigeria, were tested for antimicrobial activity. the three solvent extracts of all the species of ganoderma were active against pseudomonas syringae and bacillus subtilis, whereas none of the extracts were active against cladosporium herbarum. preliminary thin laye ...	2005	16041724
the pseudomonas syringae avrrpt2 gene contributes to virulence on tomato.	in order to cause disease on plants, gram-negative phytopathogenic bacteria introduce numerous virulence factors into the host cell in order to render host tissue more hospitable for pathogen proliferation. the mode of action of such bacterial virulence factors and their interaction with host defense pathways remain poorly understood. avrrpt2, a gene from pseudomonas syringae pv. tomato jl1065, has been shown to promote the virulence of heterologous p. syringae strains on arabidopsis thaliana. h ...	2005	16042008
quorum sensing regulates exopolysaccharide production, motility, and virulence in pseudomonas syringae.	the n-acyl homoserine lactone (ahl)-mediated quorum-sensing system in the phytopathogen pseudomonas syringae pv. syringae requires the ahl synthase ahli and the regulator ahlr, and is additionally subject to regulation by aefr. the contribution of quorum sensing to the expression of a variety of traits expected to be involved in epiphytic fitness and virulence of p syringae were examined. both an aefr- mutant and an ahli- ahlr- double mutant, deficient in ahl production, were significantly impai ...	2005	16042014
comparison of the complete genome sequences of pseudomonas syringae pv. syringae b728a and pv. tomato dc3000.	the complete genomic sequence of pseudomonas syringae pv. syringae b728a (pss b728a) has been determined and is compared with that of p. syringae pv. tomato dc3000 (pst dc3000). the two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and pst dc3000 having a more pronounced apoplastic growth habitat. the pss b728a ge ...	2005	16043691
crystal structure of yersinia enterocolitica type iii secretion chaperone syct.	pathogenic yersinia species use a type iii secretion (tts) system to deliver a number of cytotoxic effector proteins directly into the mammalian host cell. to ensure effective translocation, several such effector proteins transiently bind to specific chaperones in the bacterial cytoplasm. correspondingly, syct is the chaperone of yopt, a cysteine protease that cleaves the membrane-anchor of rho-gtpases in the host. we have analyzed the complex between yopt and syct and determined the structure o ...	2005	16046625
allophanate hydrolase, not urease, functions in bacterial cyanuric acid metabolism.	growth substrates containing an s-triazine ring are typically metabolized by bacteria to liberate 3 mol of ammonia via the intermediate cyanuric acid. over a 25-year period, a number of original research papers and reviews have stated that cyanuric acid is metabolized in two steps to the 2-nitrogen intermediate urea. in the present study, allophanate, not urea, was shown to be the 2-nitrogen intermediate in cyanuric acid metabolism in all the bacteria examined. six different experimental results ...	2005	16085834
elevated temperature enhances virulence of erwinia carotovora subsp. carotovora strain ec153 to plants and stimulates production of the quorum sensing signal, n-acyl homoserine lactone, and extracellular proteins.	erwinia carotovora subsp. atroseptica, e. carotovora subsp. betavasculorum, and e. carotovora subsp. carotovora produce high levels of extracellular enzymes, such as pectate lyase (pel), polygalacturonase (peh), cellulase (cel), and protease (prt), and the quorum-sensing signal n-acyl-homoserine lactone (ahl) at 28 degrees c. however, the production of these enzymes and ahl by these bacteria is severely inhibited during growth at elevated temperatures (31.2 degrees c for e. carotovora subsp. atr ...	2005	16085860
proteins encoded by sphingomonas elodea atcc 31461 rmla and ugpg genes, involved in gellan gum biosynthesis, exhibit both dtdp- and udp-glucose pyrophosphorylase activities.	the commercial gelling agent gellan is a heteropolysaccharide produced by sphingomonas elodea atcc 31461. in this work, we carried out the biochemical characterization of the enzyme encoded by the first gene (rmla) of the rml 4-gene cluster present in the 18-gene cluster required for gellan biosynthesis (gel cluster). based on sequence homology, the putative rml operon is presumably involved in the biosynthesis of dtdp-rhamnose, the sugar necessary for the incorporation of rhamnose in the gellan ...	2005	16085866
pseudomonas syringae genes induced during colonization of leaf surfaces.	the foliar pathogen and ice nucleator, pseudomonas syringae pv. syringae b728a, demonstrates a high level of epiphytic fitness on plants. using a promoter-trapping strategy termed habitat-inducible rescue of survival (hirs), we identified genes of this organism that are induced during colonization of healthy bean leaf surfaces. these plant-inducible genes (pigs) encode diverse cellular functions including virulence, transcription regulation, transport, nutrient acquisition and other known and un ...	2005	16104861
the heat shock genes dnak, dnaj, and grpe are involved in regulation of putisolvin biosynthesis in pseudomonas putida pcl1445.	pseudomonas putida pcl1445 produces two cyclic lipopeptides, putisolvins i and ii, which possess surfactant activity and play an important role in biofilm formation and degradation. in order to identify genes and traits that are involved in the regulation of putisolvin production of pcl1445, a tn5luxab library was generated and mutants were selected for the lack of biosurfactant production using a drop-collapsing assay. sequence analysis of the tn5luxab flanking region of one biosurfactant mutan ...	2005	16109938
ptrb of pseudomonas aeruginosa suppresses the type iii secretion system under the stress of dna damage.	in a search for regulatory genes of the type iii secretion system (ttss) in pseudomonas aeruginosa, transposon (tn5) insertional mutants of the prtr gene were found defective in the ttss. prtr is an inhibitor of prtn, which encodes a transcriptional activator for pyocin synthesis genes. in p. aeruginosa, pyocin synthesis is activated when prtr is degraded during the sos response. treatment of a wild-type p. aeruginosa strain with mitomycin c, a dna-damaging agent, resulted in the inhibition of t ...	2005	16109947
domain structure of hrpe, the hrp pilus subunit of xanthomonas campestris pv. vesicatoria.	the plant-pathogenic bacterium xanthomonas campestris pv. vesicatoria possesses a type iii secretion (tts) system necessary for pathogenicity in susceptible hosts and induction of the hypersensitive response in resistant plants. this specialized protein transport system is encoded by a 23-kb hrp (hypersensitive response and pathogenicity) gene cluster. x. campestris pv. vesicatoria produces filamentous structures, hrp pili, at the cell surface under hrp-inducing conditions. the hrp pilus acts as ...	2005	16109959
components of the legionella pneumophila flagellar regulon contribute to multiple virulence traits, including lysosome avoidance and macrophage death.	legionella pneumophila is a motile intracellular pathogen of macrophages and amoebae. when nutrients become scarce, the bacterium induces expression of transmission traits, some of which are dependent on the flagellar sigma factor flia (sigma(28)). to test how particular components of the l. pneumophila flagellar regulon contribute to virulence, we compared a flia mutant with strains whose flagellar construction is disrupted at various stages. we find that l. pneumophila requires flia to avoid l ...	2005	16113289
cryptic chlorination by a non-haem iron enzyme during cyclopropyl amino acid biosynthesis.	enzymatic incorporation of chlorine, bromine or iodine atoms occurs during the biosynthesis of more than 4,000 natural products. halogenation can have significant consequences for the bioactivity of these products so there is great interest in understanding the biological catalysts that perform these reactions. enzymes that halogenate unactivated aliphatic groups have not previously been characterized. here we report the activity of five proteins-cmaa, cmab, cmac, cmad and cmae-in the constructi ...	2005	16121186
flagellin induces innate immunity in nonhost interactions that is suppressed by pseudomonas syringae effectors.	arabidopsis nonhost1 (nho1) is required for limiting the in planta growth of nonhost pseudomonas bacteria but completely ineffective against the virulent bacterium pseudomonas syringae pv. tomato dc3000. however, the molecular basis underlying this observation remains unknown. here we show that nho1 is transcriptionally activated by flagellin. the nonhost bacterium p. syringae pv. tabaci lacking flagellin is unable to induce nho1, multiplies much better than does the wild-type bacterium, and cau ...	2005	16123135
bacterial phytopathogens and genome science.	there are now fourteen completed genomes of bacterial phytopathogens, all of which have been generated in the past six years. these genomes come from a phylogenetically diverse set of organisms, and range in size from 870 kb to more than 6mb. the publication of these annotated genomes has significantly helped our understanding of bacterial plant disease. these genomes have also provided important information about bacterial evolution. examples of recently completed genomes include: pseudomonas s ...	2005	16125997
secretome analysis reveals an arabidopsis lipase involved in defense against alternaria brassicicola.	the arabidopsis thaliana secretome was analyzed by the proteomic approach, which led to the identification of secreted proteins implicated in many aspects of cell biology. we then investigated the change in the arabidopsis secretome in response to salicylic acid and identified several proteins involved in pathogen response. one of these, a secreted lipase with a gdsl-like motif designated gdsl lipase1 (glip1), was further characterized for its function in disease resistance. glip1 plants were ma ...	2005	16126835
nppdr1, a pleiotropic drug resistance-type atp-binding cassette transporter from nicotiana plumbaginifolia, plays a major role in plant pathogen defense.	nicotiana plumbaginifolia nppdr1, a plasma membrane pleiotropic drug resistance-type atp-binding cassette transporter formerly named npabc1, has been suggested to transport the diterpene sclareol, an antifungal compound. however, direct evidence for a role of pleiotropic drug resistance transporters in the plant defense is still lacking. in situ immunolocalization and histochemical analysis using the gusa reporter gene showed that nppdr1 was constitutively expressed in the whole root, in the lea ...	2005	16126865
bioinformatics correctly identifies many type iii secretion substrates in the plant pathogen pseudomonas syringae and the biocontrol isolate p. fluorescens sbw25.	the plant pathogen pseudomonas syringae causes disease by secreting a potentially large set of virulence proteins called effectors directly into host cells, their environment, or both, using a type iii secretion system (t3ss). most p. syringae effectors have a common upstream element called the hrp box, and their n-terminal regions have amino acids biases, features that permit their bioinformatic prediction. one of the most prominent biases is a positive serine bias. we previously used the trunc ...	2005	16134900
characterization of a resistance-nodulation-cell division transporter system associated with the syr-syp genomic island of pseudomonas syringae pv. syringae.	a tripartite resistance-nodulation-cell division (rnd) transporter system, called the pseabc efflux system, was identified at the left border of the syr-syp genomic island of pseudomonas syringae pv. syringae strain b301d. the pseabc efflux system was located within a 5.7-kb operon that encodes an outer membrane protein (psea), a periplasmic membrane fusion protein (pseb), and an rnd-type cytoplasmic membrane protein (psec). the pseabc efflux system exhibited amino acid homology to a putative rn ...	2005	16151087
phylogenetic characterization of virulence and resistance phenotypes of pseudomonas syringae.	individual strains of the plant pathogenic bacterium pseudomonas syringae vary in their ability to produce toxins, nucleate ice, and resist antimicrobial compounds. these phenotypes enhance virulence, but it is not clear whether they play a dominant role in specific pathogen-host interactions. to investigate the evolution of these virulence-associated phenotypes, we used functional assays to survey for the distribution of these phenotypes among a collection of 95 p. syringae strains. all of thes ...	2005	16151103
novel lectin-like bacteriocins of biocontrol strain pseudomonas fluorescens pf-5.	bacteriocin llpa, produced by pseudomonas sp. strain bw11m1, is a peculiar antibacterial protein due to its homology to mannose-binding lectins mostly found in monocots (a. h. a. parret, g. schoofs, p. proost, and r. de mot, j. bacteriol. 185:897-908, 2003). biocontrol strain pseudomonas fluorescens pf-5 contains two llpa-like genes, named llpa1(pf-5) and llpa2(pf-5). recombinant escherichia coli cells expressing llpa1(pf-5) or llpa2(pf-5) acquired bacteriocin activity and secreted a 31-kda prot ...	2005	16151105
plasmid donor affects host range of promiscuous incp-1beta plasmid pb10 in an activated-sludge microbial community.	horizontal transfer of multiresistance plasmids in the environment contributes to the growing problem of drug-resistant pathogens. even though the plasmid host cell is the primary environment in which the plasmid functions, possible effects of the plasmid donor on the range of bacteria to which plasmids spread in microbial communities have not been investigated. in this study we show that the host range of a broad-host-range plasmid within an activated-sludge microbial community was influenced b ...	2005	16151119
spatial organization of dual-species bacterial aggregates on leaf surfaces.	the spatial organization of cells within bacterial aggregates on leaf surfaces was determined for pair-wise mixtures of three different bacterial species commonly found on leaves, pseudomonas syringae, pantoea agglomerans, and pseudomonas fluorescens. cells were coinoculated onto bean plants and allowed to grow under moist conditions, and the resulting aggregates were examined in situ by epifluorescence microscopy. each bacterial strain could be localized because it expressed either the green or ...	2005	16151141
isolation of ralstonia solanacearum hrpb constitutive mutants and secretion analysis of hrpb-regulated gene products that share homology with known type iii effectors and enzymes.	the hrp type iii secretion system (ttss) is essential for the pathogenicity of the gram-negative plant pathogen ralstonia solanacearum. to examine the secretion of type iii effector proteins via the hrp ttss, a screen was done of mutants constitutively expressing the hrpb gene, which encodes an arac-type transcriptional activator for the hrp regulon. a mutant was isolated that in an hrp-inducing medium expresses several hrpb-regulated genes 4.9-83-fold higher than the wild-type. r. solanacearum ...	2005	16151200
impact of muts inactivation on foreign dna acquisition by natural transformation in pseudomonas stutzeri.	in prokaryotic mismatch repair the muts protein and its homologs recognize the mismatches. the muts gene of naturally transformable pseudomonas stutzeri atcc 17587 (genomovar 2) was identified and characterized. the deduced amino acid sequence (859 amino acids; 95.6 kda) displayed protein domains i to iv and a mismatch-binding motif similar to those in muts of escherichia coli. a muts::aac mutant showed 20- to 163-fold-greater spontaneous mutability. transformation experiments with dna fragments ...	2005	15601698
regulation of the pseudomonas sp. strain adp cyanuric acid degradation operon.	pseudomonas sp. strain adp is the model strain for studying bacterial degradation of the s-triazine herbicide atrazine. in this work, we focused on the expression of the atzdef operon, involved in mineralization of the central intermediate of the pathway, cyanuric acid. expression analysis of atzd-lacz fusions in pseudomonas sp. strain adp and pseudomonas putida showed that atzdef is subjected to dual regulation in response to nitrogen limitation and cyanuric acid. the gene adjacent to atzd, orf ...	2005	15601699
fate of predator and prey proteins during growth of bdellovibrio bacteriovorus on escherichia coli and pseudomonas syringae prey.	a two-dimensional electrophoretic analysis of protein distribution followed by identification of selected proteins by mass spectrometry was performed on fresh bdellovibrio cultures containing attack phase cells of the predatory bacterium bdellovibrio bacteriovorus strain 109j-1 and the remains of an escherichia coli or a pseudomonas syringae pv. tomato prey. cleavage of the peptidoglycan-associated outer membrane proteins (omps) ompa in e. coli and oprf in p. syringae occurred in both prey. the ...	2005	15601717
pseudomonas aeruginosa genome database and pseudocap: facilitating community-based, continually updated, genome annotation.	using the pseudomonas aeruginosa genome project as a test case, we have developed a database and submission system to facilitate a community-based approach to continually updated genome annotation (http://www.pseudomonas.com). researchers submit proposed annotation updates through one of three web-based form options which are then subjected to review, and if accepted, entered into both the database and log file of updates with author acknowledgement. in addition, a coordinator continually review ...	2005	15608211
pseudomonas aeruginosa genome database and pseudocap: facilitating community-based, continually updated, genome annotation.	using the pseudomonas aeruginosa genome project as a test case, we have developed a database and submission system to facilitate a community-based approach to continually updated genome annotation (http://www.pseudomonas.com). researchers submit proposed annotation updates through one of three web-based form options which are then subjected to review, and if accepted, entered into both the database and log file of updates with author acknowledgement. in addition, a coordinator continually review ...	2005	15608211
tractor_db: a database of regulatory networks in gamma-proteobacterial genomes.	experimental data on the escherichia coli transcriptional regulatory system has been used in the past years to predict new regulatory elements (promoters, transcription factors (tfs), tfs' binding sites and operons) within its genome. as more genomes of gamma-proteobacteria are being sequenced, the prediction of these elements in a growing number of organisms has become more feasible, as a step towards the study of how different bacteria respond to environmental changes at the level of transcrip ...	2005	15608293
tractor_db: a database of regulatory networks in gamma-proteobacterial genomes.	experimental data on the escherichia coli transcriptional regulatory system has been used in the past years to predict new regulatory elements (promoters, transcription factors (tfs), tfs' binding sites and operons) within its genome. as more genomes of gamma-proteobacteria are being sequenced, the prediction of these elements in a growing number of organisms has become more feasible, as a step towards the study of how different bacteria respond to environmental changes at the level of transcrip ...	2005	15608293
erwinia chrysanthemi requires a second iron transport route dependent of the siderophore achromobactin for extracellular growth and plant infection.	full virulence of the pectinolytic enterobacterium erwinia chrysanthemi strain 3937 depends on the production in planta of the catechol-type siderophore chrysobactin. under iron-limited conditions, e. chrysanthemi synthesizes a second siderophore called achromobactin belonging to the hydroxy/carboxylate class of siderophore. in this study, we cloned and functionally characterized a 13 kb long operon comprising seven genes required for the biosynthesis (acs) and extracellular release (yhca) of ac ...	2005	15612933
molecular cloning, sequence analysis, and heterologous expression of the phosphinothricin tripeptide biosynthetic gene cluster from streptomyces viridochromogenes dsm 40736.	a fosmid library from genomic dna of streptomyces viridochromogenes dsm 40736 was constructed and screened for the presence of genes known to be involved in the biosynthesis of phosphinothricin tripeptide (ptt). eight positives were identified, one of which was able to confer ptt biosynthetic capability upon streptomyces lividans after integration of the fosmid into the chromosome of this heterologous host. sequence analysis of the 40,241-bp fosmid insert revealed 29 complete open reading frames ...	2005	15616300
genes and enzymes involved in bacterial oxidation and reduction of inorganic arsenic.		2005	15691908
regulation of resistance to copper in xanthomonas axonopodis pv. vesicatoria.	copper-resistant strains of xanthomonas axonopodis pv. vesicatoria were previously shown to carry plasmid-borne copper resistance genes related to the cop and pco operons of pseudomonas syringae and escherichia coli, respectively. however, instead of the two-component (coprs and pcors) systems determining copper-inducible expression of the operons in p. syringae and e. coli, a novel open reading frame, copl, was found to be required for copper-inducible expression of the downstream multicopper o ...	2005	15691931
adaptation of the yeast ura3 selection system to gram-negative bacteria and generation of a {delta}betcde pseudomonas putida strain.	a general procedure for efficient generation of gene knockouts in gram-negative bacteria by the adaptation of the saccharomyces cerevisiae ura3 selection system is described. a pseudomonas putida strain lacking the ura3 homolog pyrf (encoding orotidine-5'-phosphate decarboxylase) was constructed, allowing the use of a plasmid-borne copy of the gene as the target of selection. the delivery vector ptec contains the pyrf gene and promoter, a conditional origin of replication (orir6k), an origin of ...	2005	15691944
unique kinetic properties of phenol-degrading variovorax strains responsible for efficient trichloroethylene degradation in a chemostat enrichment culture.	a chemostat enrichment of soil bacteria growing on phenol as the sole carbon source has been shown to exhibit quite high trichloroethylene (tce)-degrading activities. to identify the bacterial populations responsible for the high tce-degrading activity, a multidisciplinary survey of the chemostat enrichment was conducted by employing molecular-ecological and culture-dependent approaches. three chemostat enrichment cultures were newly developed under different phenol-loading conditions (0.25, 0.7 ...	2005	15691947
a high-throughput, near-saturating screen for type iii effector genes from pseudomonas syringae.	pseudomonas syringae strains deliver variable numbers of type iii effector proteins into plant cells during infection. these proteins are required for virulence, because strains incapable of delivering them are nonpathogenic. we implemented a whole-genome, high-throughput screen for identifying p. syringae type iii effector genes. the screen relied on facs and an arabinose-inducible hrpl sigma factor to automate the identification and cloning of hrpl-regulated genes. we determined whether candid ...	2005	15701698
ups1, an arabidopsis thaliana camalexin accumulation mutant defective in multiple defence signalling pathways.	we report the characterization of an arabidopsis thaliana mutant, ups1, isolated on the basis of reduced expression of phosphoribosylanthranilate transferase, a tryptophan biosynthetic enzyme. ups1 also exhibits defects in a wide range of defence responses. after infection with pseudomonas syringae or botrytis cinerea, the expression of genes regulated by both the salicylic acid and jasmonic acid/ethylene pathways is reduced in ups1 compared with wild type. camalexin accumulation in ups1 is grea ...	2005	15703055
exoribonuclease r interacts with endoribonuclease e and an rna helicase in the psychrotrophic bacterium pseudomonas syringae lz4w.	endoribonuclease e, a key enzyme involved in rna decay and processing in bacteria, organizes a protein complex called degradosome. in escherichia coli, rhodobacter capsulatus, and streptomyces coelicolor, rnase e interacts with the phosphate-dependent exoribonuclease polynucleotide phosphorylase, dead-box helicase(s), and additional factors in an rna-degrading complex. to characterize the degradosome of the psychrotrophic bacterium pseudomonas syringae lz4w, rnase e was enriched by cation exchan ...	2005	15705581
stress induces the expression of atnadk-1, a gene encoding a nad(h) kinase in arabidopsis thaliana.	a novel arabidopsis thaliana gene (atnadk-1) was identified based on its response to radiation and oxidative stress. levels of atnadk-1 mrna increase eight-fold following exposure to ionising radiation and are enhanced three-fold by treatment with hydrogen peroxide. the gene also appears to be differentially regulated during compatible and incompatible plant-pathogen interactions in response to pseudomonas syringae pv. tomato. the full-length atnadk-1 cdna encodes a 58-kda protein that shows hig ...	2005	15711971
protein domains and architectural innovation in plant-associated proteobacteria.	evolution of new complex biological behaviour tends to arise by novel combinations of existing building blocks. the functional and evolutionary building blocks of the proteome are protein domains, the function of a protein being dependent on its constituent domains. we clustered completely-sequenced proteomes of prokaryotes on the basis of their protein domain content, as defined by pfam (release 16.0). this revealed that, although there was a correlation between phylogeny and domain content, ot ...	2005	15715905
overexpression of a pepper basic pathogenesis-related protein 1 gene in tobacco plants enhances resistance to heavy metal and pathogen stresses.	a pepper gene, cabpr1, which encodes basic pathogenesis-related protein 1, has been reported to be strongly induced after ethephon treatment, wounding, and tobacco mosaic virus infection. the potential role of cabpr1 in tolerance of biotic or abiotic stresses was examined in transgenic nicotiana tabacum cv. xanthi plants. overexpression of cabpr1 in tobacco plants enhanced tolerance not only to heavy metal stresses, but also to the oomycete pathogen phytophthora nicotianae, and the bacterial pat ...	2005	15719238
involvement of the small gtpase rac in the defense responses of tobacco to pathogens.	during the hypersensitive response (hr), plants accumulate reactive oxygen species (ros) that are likely generated at least in part by an nadph oxidase similar to that found in mammalian neutrophils. an essential regulator of mammalian nadph oxidase is the small gtp-binding protein rac. to investigate whether rac also regulates the pathogen-induced oxidative burst in plants, a dominant negative form of the rice osrac1 gene was overexpressed in tobacco carrying the n resistance gene. following in ...	2005	15720080
pseudomonas aeruginosa fiml regulates multiple virulence functions by intersecting with vfr-modulated pathways.	virulence of pseudomonas aeruginosa involves the co-ordinate expression of a range of factors including type iv pili (tfp), the type iii secretion system (ttss) and quorum sensing. tfp are required for twitching motility, efficient biofilm formation, and for adhesion and type iii secretion (tts)-mediated damage to mammalian cells. we describe a novel gene (fiml) that is required for tfp biogenesis and function, for tts and for normal biofilm development in p. aeruginosa. the predicted product of ...	2005	15720546
dissecting the beta-aminobutyric acid-induced priming phenomenon in arabidopsis.	plants treated with the nonprotein amino acid beta-aminobutyric acid (baba) develop an enhanced capacity to resist biotic and abiotic stresses. this baba-induced resistance (baba-ir) is associated with an augmented capacity to express basal defense responses, a phenomenon known as priming. based on the observation that high amounts of baba induce sterility in arabidopsis thaliana, a mutagenesis screen was performed to select mutants impaired in baba-induced sterility (ibs). here, we report the i ...	2005	15722464
role of beta-oxidation in jasmonate biosynthesis and systemic wound signaling in tomato.	jasmonic acid (ja) is a lipid-derived signal that regulates plant defense responses to biotic stress. here, we report the characterization of a ja-deficient mutant of tomato (lycopersicon esculentum) that lacks local and systemic expression of defensive proteinase inhibitors (pis) in response to wounding. map-based cloning studies demonstrated that this phenotype results from loss of function of an acyl-coa oxidase (acx1a) that catalyzes the first step in the peroxisomal beta-oxidation stage of ...	2005	15722469
rin13 is a positive regulator of the plant disease resistance protein rpm1.	the rpm1 protein confers resistance to pseudomonas syringae pv tomato dc3000 expressing either of the type iii effector proteins avrrpm1 or avrb. here, we describe the isolation and functional characterization of rpm1 interacting protein 13 (rin13), a resistance protein interactor shown to positively enhance resistance function. ectopic expression of rin13 (rin13s) enhanced bacterial restriction mechanisms but paradoxically abolished the normally rapid hypersensitive response (hr) controlled by ...	2005	15722472
variation in the strength of selected codon usage bias among bacteria.	among bacteria, many species have synonymous codon usage patterns that have been influenced by natural selection for those codons that are translated more accurately and/or efficiently. however, in other species selection appears to have been ineffective. here, we introduce a population genetics-based model for quantifying the extent to which selection has been effective. the approach is applied to 80 phylogenetically diverse bacterial species for which whole genome sequences are available. the ...	2005	15728743
a part of ice nucleation protein exhibits the ice-binding ability.	we generated a recombinant 96-residue polypeptide corresponding to a sequence tyr176-gly273 of ice nucleation protein from pseudomonas syringae (denoted inp96). inp96 exhibited an ability to shape an ice crystal, whose morphology is highly similar to the hexagonal-bipyramid generally identified for antifreeze protein. inp96 also showed a non-linear, concentration-dependent retardation of ice growth. additionally, circular dichroism and nmr measurements suggested a local structural construction i ...	2005	15733862
molecular and biochemical characterization of 2-hydroxyisoflavanone dehydratase. involvement of carboxylesterase-like proteins in leguminous isoflavone biosynthesis.	isoflavonoids are ecophysiologically active secondary metabolites of the leguminosae and known for health-promoting phytoestrogenic functions. isoflavones are synthesized by 1,2-elimination of water from 2-hydroxyisoflavanones, the first intermediate with the isoflavonoid skeleton, but details of this dehydration have been unclear. we screened the extracts of repeatedly fractionated escherichia coli expressing a glycyrrhiza echinata cdna library for the activity to convert a radiolabeled precurs ...	2005	15734910
crystal structure of a novel shikimate dehydrogenase from haemophilus influenzae.	to date two classes of shikimate dehydrogenases have been identified and characterized, ydib and aroe. ydib is a bifunctional enzyme that catalyzes the reversible reductions of dehydroquinate to quinate and dehydroshikimate to shikimate in the presence of either nadh or nadph. in contrast, aroe catalyzes the reversible reduction of dehydroshikimate to shikimate in the presence of nadph. here we report the crystal structure and biochemical characterization of hi0607, a novel class of shikimate de ...	2005	15735308
powerful screens for bacterial virulence proteins.		2005	15738387
bioprocess intensification in flow-through monolithic microbioreactors with immobilized bacteria.	microporous polymers (with porosity up to 90%) with a well-prescribed internal microstructure were prepared in monolithic form to construct a flow-through microbioreactor in which phenol-degrading bacteria, pseudomonas syringae, was immobilized. initially, bacteria was forced seeded within the pores and subsequently allowed to proliferate followed by acclimatization and phenol degradation at various initial substrate concentrations and flow rates. two types of microporous polymer were used as th ...	2005	15742387
molecular analysis of the rebeccamycin l-amino acid oxidase from lechevalieria aerocolonigenes atcc 39243.	rebeccamycin, a member of the tryptophan-derived indolocarbazole family, is produced by lechevalieria aerocolonigenes atcc 39243. the biosynthetic pathway that specifies biosynthesis of this important metabolite is comprised of 11 genes spanning 18 kb of dna. a presumed early enzyme involved in elaboration of the rebeccamycin aglycone is encoded by rebo, located at the left-hand region of the reb gene cluster. the deduced protein product, rebo (51.9 kda), is an l-amino acid oxidase (l-aao) that ...	2005	15743957
comparative genomic analysis of the ppt23a plasmid family of pseudomonas syringae.	members of the ppt23a plasmid family of pseudomonas syringae play an important role in the interaction of this bacterial pathogen with host plants. complete sequence analysis of several ppt23a family plasmids (pfps) has provided a glimpse of the gene content and virulence function of these plasmids. we constructed a macroarray containing 161 genes to estimate and compare the gene contents of 23 newly analyzed and eight known pfps from 12 pathovars of p. syringae, which belong to four genomospeci ...	2005	15743960
evidence for diversifying selection at the pyoverdine locus of pseudomonas aeruginosa.	pyoverdine is the primary siderophore of the gram-negative bacterium pseudomonas aeruginosa. the pyoverdine region was recently identified as the most divergent locus alignable between strains in the p. aeruginosa genome. here we report the nucleotide sequence and analysis of more than 50 kb in the pyoverdine region from nine strains of p. aeruginosa. there are three divergent sequence types in the pyoverdine region, which correspond to the three structural types of pyoverdine. the pyoverdine ou ...	2005	15743962
biosynthesis of auxin by the gram-positive phytopathogen rhodococcus fascians is controlled by compounds specific to infected plant tissues.	the role and metabolism of indole-3-acetic acid in gram-negative bacteria is well documented, but little is known about indole-3-acetic acid biosynthesis and regulation in gram-positive bacteria. the phytopathogen rhodococcus fascians, a gram-positive organism, incites diverse developmental alterations, such as leafy galls, on a wide range of plants. phenotypic analysis of a leafy gall suggests that auxin may play an important role in the development of the symptoms. we show here for the first t ...	2005	15746315
genomic analysis of bacteriophage phijl001: insights into its interaction with a sponge-associated alpha-proteobacterium.	bacteriophage phijl001 infects a novel marine bacterium in the alpha subclass of the proteobacteria isolated from the marine sponge ircinia strobilina. phijl001 is a siphovirus and forms turbid plaques on its host. the genome sequence of phijl001 was determined in order to better understand the interaction between the marine phage and its sponge-associated host bacterium. the complete genome sequence of phijl001 comprised 63,469 bp with an overall g+c content of 62%. the genome has 91 predicted ...	2005	15746365
activation of a phytopathogenic bacterial effector protein by a eukaryotic cyclophilin.	innate immunity in higher plants invokes a sophisticated surveillance system capable of recognizing bacterial effector proteins. in arabidopsis, resistance to infection by strains of pseudomonas syringae expressing the effector avrrpt2 requires the plant resistance protein rps2. avrrpt2 was identified as a putative cysteine protease that results in the elimination of the arabidopsis protein rin4. rin4 cleavage serves as a signal to activate rps2-mediated resistance. avrrpt2 is delivered into the ...	2005	15746386
cis-trans isomerase gene in psychrophilic pseudomonas syringae is constitutively expressed during growth and under conditions of temperature and solvent stress.	in a recent study, we established that psychrophilic pseudomonas syringae (lz4w) requires trans-monounsaturated fatty acid for growth at higher temperatures (kiran et al. in extremophiles, 2004). it was also demonstrated that the cti gene was highly conserved and exhibited high sequence identity with cti of other pseudomonas spp. (kiran et al. in extremophiles, 2004). therefore it would be interesting to understand the expression of the cti gene so as to unravel the molecular basis of adaptation ...	2005	15747056
molecular genetic evidence for the role of sgt1 in the intramolecular complementation of bs2 protein activity in nicotiana benthamiana.	pepper plants (capsicum annuum) containing the bs2 resistance gene are resistant to strains of xanthomonas campestris pv vesicatoria (xcv) expressing the bacterial effector protein avrbs2. avrbs2 is delivered directly to the plant cell via the type iii protein secretion system (ttss) of xcv. upon recognition of avrbs2 by plants expressing the bs2 gene, a signal transduction cascade is activated leading to a bacterial disease resistance response. here, we describe a novel pathosystem that consist ...	2005	15749757
histone deacetylase19 is involved in jasmonic acid and ethylene signaling of pathogen response in arabidopsis.	histone acetylation is modulated through the action of histone acetyltransferases and deacetylases, which play key roles in the regulation of eukaryotic gene expression. previously, we have identified a yeast histone deacetylase reduced potassium dependency3 (rpd3) homolog, histone deacetylase19 (hda19) (atrpd3a), in arabidopsis thaliana. here, we report further study of the expression and function of hda19. analysis of arabidopsis plants containing the hda19:beta-glucuronidase fusion gene revea ...	2005	15749761
interaction of nimin1 with npr1 modulates pr gene expression in arabidopsis.	the arabidopsis thaliana nonexpresser of pr genes1 (npr1, also known as nim1) protein is an essential positive regulator of salicylic acid (sa)-induced pathogenesis-related (pr) gene expression and systemic acquired resistance (sar). pr gene activity is regulated at the level of redox-dependent nuclear transport of npr1. npr1 interacts with members of the tga family of transcription factors that are known to bind to sa-responsive elements in the pr-1 promoter. in an attempt to identify proteins ...	2005	15749762
molecular basis for the rin4 negative regulation of rps2 disease resistance.	recent studies have demonstrated that rps2, a plasma membrane-localized nucleotide binding site/leucine-rich repeat protein from arabidopsis thaliana, associates with rpm1 interacting protein 4 (rin4) and that this association functions to modulate the rps2-mediated defense pathway in response to the bacterial effector protein avrrpt2. in addition to negatively regulating rps2 activity, rin4 is also a target of avrrpt2, a cys protease and cognate bacterial effector protein of rps2. nicotiana ben ...	2005	15749765
a spatially localized rhomboid protease cleaves cell surface adhesins essential for invasion by toxoplasma.	apicomplexan parasites cause serious human and animal diseases, the treatment of which requires identification of new therapeutic targets. host-cell invasion culminates in the essential cleavage of parasite adhesins, and although the cleavage site for several adhesins maps within their transmembrane domains, the protease responsible for this processing has not been discovered. we have identified, cloned, and characterized the five nonmitochondrial rhomboid intramembrane proteases encoded in the ...	2005	15753289
a copper(i) protein possibly involved in the assembly of cua center of bacterial cytochrome c oxidase.	sco1 and cox17 are accessory proteins required for the correct assembly of eukaryotic cytochrome c oxidase. at variance with sco1, cox17 orthologs are found only in eukaryotes. we browsed bacterial genomes to search proteins functionally equivalent to cox17, and we identified a class of proteins of unknown function displaying a conserved gene neighborhood to bacterial sco1 genes, all sharing a potential metal binding motif h(m)x10mx21hxm. two members of this group, dr1885 from deinococcus radiod ...	2005	15753304
detection of and response to signals involved in host-microbe interactions by plant-associated bacteria.	diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. this concept was first demonstrated for the members of the family rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and anima ...	2005	15755957
making connections between novel transcription factors and their dna motifs.	the key components of a transcriptional regulatory network are the connections between trans-acting transcription factors and cis-acting dna-binding sites. in spite of several decades of intense research, only a fraction of the estimated approximately 300 transcription factors in escherichia coli have been linked to some of their binding sites in the genome. in this paper, we present a computational method to connect novel transcription factors and dna motifs in e. coli. our method uses three ty ...	2005	15653829
identification of pathogen-responsive regions in the promoter of a pepper lipid transfer protein gene (caltpi) and the enhanced resistance of the caltpi transgenic arabidopsis against pathogen and environmental stresses.	the 5' flanking region of the caltpi gene, which encodes a basic lipid transfer protein, was isolated and characterized from the genomic dna of capsicum annuum. four different regions of the promoter sequence of the caltpi gene were fused to the beta-glucuronidase (gus) coding region. in an agrobacterium-mediated transient expression assay, the transcriptional activations of the promoter deletions were examined in tobacco leaves after infection with pseudomonas syringae pv. tabaci, and treatment ...	2005	15654638
pseudomonas syringae manipulates systemic plant defenses against pathogens and herbivores.	many pathogens are virulent because they specifically interfere with host defense responses and therefore can proliferate. here, we report that virulent strains of the bacterial phytopathogen pseudomonas syringae induce systemic susceptibility to secondary p. syringae infection in the host plant arabidopsis thaliana. this systemic induced susceptibility (sis) is in direct contrast to the well studied avirulence/r gene-dependent resistance response known as the hypersensitive response that elicit ...	2005	15657122
pyruvate:quinone oxidoreductase from corynebacterium glutamicum: purification and biochemical characterization.	pyruvate:quinone oxidoreductase catalyzes the oxidative decarboxylation of pyruvate to acetate and co2 with a quinone as the physiological electron acceptor. so far, this enzyme activity has been found only in escherichia coli. using 2,6-dichloroindophenol as an artificial electron acceptor, we detected pyruvate:quinone oxidoreductase activity in cell extracts of the amino acid producer corynebacterium glutamicum. the activity was highest (0.055 +/- 0.005 u/mg of protein) in cells grown on compl ...	2005	15659664
nopb, a type iii secreted protein of rhizobium sp. strain ngr234, is associated with pilus-like surface appendages.	rhizobium sp. strain ngr234 possesses a functional type three secretion system (ttss), through which a number of proteins, called nodulation outer proteins (nops), are delivered to the outside of the cell. a major constraint to the identification of nops is their low abundance in the supernatants of ngr234 strains grown in culture. to overcome this limitation, a more sensitive proteomics-based strategy was developed. secreted proteins from wild-type ngr234 were separated by two-dimensional gel e ...	2005	15659692
type iii secretion chaperones of pseudomonas syringae protect effectors from lon-associated degradation.	the hrp type iii secretion system (ttss) of pseudomonas syringae translocates effector proteins into the cytoplasm of host cells. proteolysis of hrpr by lon has been shown to negatively regulate the hrp ttss. the inability to bypass lon-associated effects on the regulatory system by ectopic expression of the known regulators suggested a second site of action for lon in ttss-dependent effector secretion. in this study we report that ttss-dependent effectors are subject to the proteolytic degradat ...	2005	15661015
antibacterial activity of seed proteins of robinia pseudoacacia.	a low molecular weight cationic peptide was isolated from robinia pseudoacacia seed and tested in vitro against seven bacteria (corynebacterium michiganense, staphylococcus aureus, bacillus subtilis, erwinia carotovora subsp. carotovora, pseudomonas syringae pv syringae, xanthomonas campestris pv campestris, and escherichia coli). the peptide inhibited the growth of the tested strains. the effective concentrations required for 50% inhibition of bacterial growth ranged between 20 and 120 microg m ...	2005	15664465
espj is a prophage-carried type iii effector protein of attaching and effacing pathogens that modulates infection dynamics.	enterohemorrhagic escherichia coli, enteropathogenic e. coli, and citrobacter rodentium are highly adapted enteropathogens that successfully colonize their host's gastrointestinal tract via the formation of attaching and effacing (a/e) lesions. these pathogens utilize a type iii secretion system (ttss) apparatus, encoded by the locus of enterocyte effacement, to translocate bacterial effector proteins into epithelial cells. here, we report the identification of espj (e. coli-secreted protein j), ...	2005	15664905
involvement of acetosyringone in plant-pathogen recognition.	in this study, acetosyringone was identified as one of the major extracellular phenolics in tobacco suspension cells and was shown to have bioactive properties that influence early events in plant-bacterial pathogenesis. in our model system, tobacco cell suspensions treated with bacterial isolate pseudomonas syringae wt (hr+) undergo a resistant interaction characterized by a burst in oxygen uptake several hours after inoculation. when the extracellular concentration of acetosyringone in tobacco ...	2005	15670760
molecular nature of spontaneous modifications in gacs which cause colony phase variation in pseudomonas sp. strain pcl1171.	pseudomonas sp. strain pcl1171 displays colony phase variation between opaque phase i and translucent phase ii colonies, thereby regulating the production of secondary metabolites and exoenzymes. complementation and sequence analysis of 26 phase ii mutants and of 13 wild-type phase ii sectors growing out of phase i colonies showed that in all these cases the phase ii phenotype is caused by spontaneous mutations in gaca or/and gacs. mutation of gac reduced both the length of the lag phase and the ...	2005	15629930
the hrpk operon of pseudomonas syringae pv. tomato dc3000 encodes two proteins secreted by the type iii (hrp) protein secretion system: hopb1 and hrpk, a putative type iii translocator.	pseudomonas syringae is a gram-negative bacterial plant pathogen that is dependent on a type iii protein secretion system (ttss) and the effector proteins it translocates into plant cells for pathogenicity. the p. syringae ttss is encoded by hrp-hrc genes that reside in a central region of a pathogenicity island (pai). flanking one side of this pai is the exchangeable effector locus (eel). we characterized the transcriptional expression of the open reading frames (orfs) within the eel of p. syri ...	2005	15629936
evidence for two flagellar stators and their role in the motility of pseudomonas aeruginosa.	pseudomonas aeruginosa is a ubiquitous bacterium capable of twitching, swimming, and swarming motility. in this study, we present evidence that p. aeruginosa has two flagellar stators, conserved in all pseudomonads as well as some other gram-negative bacteria. either stator is sufficient for swimming, but both are necessary for swarming motility under most of the conditions tested, suggesting that these two stators may have different roles in these two types of motility.	2005	15629949
type iii secretion chaperones shcs1 and shco1 from pseudomonas syringae pv. tomato dc3000 bind more than one effector.	the hrp-type iii secretion (tts) system is a key pathogenicity factor of the plant pathogen pseudomonas syringae pv. tomato dc3000 that translocates effector proteins into the cytosol of the eukaryotic host cell. the translocation of a subset of effectors is dependent on specific chaperones. in this study an operon encoding a tts chaperone (shcs1) and the truncated effector hops1' was characterized. yeast two-hybrid analysis and pull-down assays demonstrated that these proteins interact. using p ...	2005	15632444