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brucella suis urease encoded by ure1 but not ure2 is necessary for intestinal infection of balb/c mice.in prokaryotes, the ureases are multi-subunit, nickel-containing enzymes that catalyze the hydrolysis of urea to carbon dioxide and ammonia. the brucella genomes contain two urease operons designated as ure1 and ure2. we investigated the role of the two brucella suis urease operons on the infection, intracellular persistence, growth, and resistance to low-ph killing.200717578575
b. thuringiensis is a poor colonist of leaf surfaces.the ability of several bacillus thuringiensis strains to colonize plant surfaces was assessed and compared with that of more common epiphytic bacteria. while all b. thuringiensis strains multiplied to some extent after inoculation on bean plants, their maximum epiphytic population sizes of 10(6) cfu/g of leaf were always much less than that achieved by other resident epiphytic bacteria or an epiphytically fit pseudomonas fluorescens strain, which attained population sizes of about 10(7) cfu/g of ...200817587074
the syntaxin syp132 contributes to plant resistance against bacteria and secretion of pathogenesis-related protein 1.in contrast to many mammalian pathogens, potential bacterial pathogens of plants remain outside the host cell. the plant must, therefore, promote an active resistance mechanism to combat the extracellular infection. how this resistance against bacteria is manifested and whether similar processes mediate basal, gene-for-gene, and salicylate-associated defense, however, are poorly understood. here, we identify a specific plasma membrane syntaxin, nbsyp132, as a component contributing to gene-for-g ...200717592123
convergent evolution of phytopathogenic pseudomonads onto hazelnut.pseudomonas syringae pv. avellanae (synonym: p. avellanae, pav) is the causal agent of hazelnut decline in greece and italy. the population structure and evolutionary relationships of 22 strains from these two countries were examined by multilocus sequence typing (mlst) of four housekeeping genes (gapa, glta, gyrb and rpod). neighbour-joining and maximum-likelihood phylogenetic analysis revealed that greek strains isolated from the original 1976 outbreak of hazelnut decline through 1990 were ver ...200717600051
comparative transcriptome analysis reveals common and specific tags for root hair and crack-entry invasion in sesbania rostrata.the tropical legume sesbania rostrata provides its microsymbiont azorhizobium caulinodans with versatile invasion strategies to allow nodule formation in temporarily flooded habitats. in aerated soils, the bacteria enter via the root hair curling mechanism. submergence prevents this epidermal invasion by accumulation of inhibiting concentrations of ethylene and, under these conditions, the bacterial colonization occurs via intercellular cortical infection at lateral root bases. the transcriptome ...200717600136
pto- and prf-mediated recognition of avrpto and avrptob restricts the ability of diverse pseudomonas syringae pathovars to infect tomato.the molecular basis underlying the ability of pathogens to infect certain plant species and not others is largely unknown. pseudomonas syringae is a useful model species for investigating this phenomenon because it comprises more than 50 pathovars which have narrow host range specificities. tomato (solanum lycopersicum) is a host for p. syringae pv. tomato, the causative agent of bacterial speck disease, but is considered a nonhost for other p. syringae pathovars. host resistance in tomato to ba ...200717601168
identification of a biosynthetic gene cluster and the six associated lipopeptides involved in swarming motility of pseudomonas syringae pv. tomato dc3000.pseudomonas species are known to be prolific producers of secondary metabolites that are synthesized wholly or in part by nonribosomal peptide synthetases. in an effort to identify additional nonribosomal peptides produced by these bacteria, a bioinformatics approach was used to "mine" the genome of pseudomonas syringae pv. tomato dc3000 for the metabolic potential to biosynthesize previously unknown nonribosomal peptides. herein we describe the identification of a nonribosomal peptide biosynthe ...200717601782
alginate production by pseudomonas putida creates a hydrated microenvironment and contributes to biofilm architecture and stress tolerance under water-limiting conditions.biofilms exist in a variety of habitats that are routinely or periodically not saturated with water, and residents must integrate cues on water abundance (matric stress) or osmolarity (solute stress) into lifestyle strategies. here we examine this hypothesis by assessing the extent to which alginate production by pseudomonas putida strain mt-2 and by other fluorescent pseudomonads occurs in response to water limitations and how the presence of alginate in turn influences biofilm development and ...200717601783
bacterial cyclic beta-(1,2)-glucan acts in systemic suppression of plant immune responses.although cyclic glucans have been shown to be important for a number of symbiotic and pathogenic bacterium-plant interactions, their precise roles are unclear. here, we examined the role of cyclic beta-(1,2)-glucan in the virulence of the black rot pathogen xanthomonas campestris pv campestris (xcc). disruption of the xcc nodule development b (ndvb) gene, which encodes a glycosyltransferase required for cyclic glucan synthesis, generated a mutant that failed to synthesize extracellular cyclic be ...200717601826
insights into polymer versus oligosaccharide synthesis: mutagenesis and mechanistic studies of a novel levansucrase from bacillus megaterium.a novel levansucrase was identified in the supernatant of a cell culture of bacillus megaterium dsm319. in order to test for the contribution of specific amino acid residues to levansucrase catalysis, the wild-type enzyme along with 16 variants based on sequence alignments and structural information were heterologously produced in escherichia coli. the purified enzymes were characterized kinetically and the product spectrum of each variant was determined. comparison of the x-ray structures of th ...200717608626
a temperature-sensing histidine kinase: function, genetics, and membrane topology.two-component systems provide a means for bacteria to sense and adapt to environmental signals in order to survive in a continuously changing environment. understanding of the mechanism by which these systems function is important in combating bacterial infections because many bacterial two-component systems are associated with virulence. the plant pathogenic bacterium pseudomonas syringae pv. glycinea pg4180 synthesizes high levels of the phytotoxin coronatine at the virulence-promoting tempera ...200717609134
genetic diversity among enterococcus faecalis.enterococcus faecalis, a ubiquitous member of mammalian gastrointestinal flora, is a leading cause of nosocomial infections and a growing public health concern. the enterococci responsible for these infections are often resistant to multiple antibiotics and have become notorious for their ability to acquire and disseminate antibiotic resistances. in the current study, we examined genetic relationships among 106 strains of e. faecalis isolated over the past 100 years, including strains identified ...200717611618
edr2 negatively regulates salicylic acid-based defenses and cell death during powdery mildew infections of arabidopsis thaliana.the hypersensitive necrosis response (hr) of resistant plants to avirulent pathogens is a form of programmed cell death in which the plant sacrifices a few cells under attack, restricting pathogen growth into adjacent healthy tissues. in spite of the importance of this defense response, relatively little is known about the plant components that execute the cell death program or about its regulation in response to pathogen attack.200717612410
rcs and phopq regulatory overlap in the control of salmonella enterica virulence.genetic screens based on the use of mudj-generated lac fusions permitted the identification of novel genes regulated by the rcs signal transduction system in salmonella enterica serovar typhimurium. besides genes that are also found in the escherichia coli genome, our screens identified salmonella-specific genes regulated by rcsb, including bapa, siie, srfa, and srfb. here we show that the srfabc operon is negatively regulated by rcsb and by phop. in vivo studies using mutants with constitutive ...200717616593
improvement of the cryopreservation of the fungal starter geotrichum candidum by artificial nucleation and temperature downshift control.food industry tends towards the use of controlled microorganisms in order to improve its technologies including frozen starter production. the fungus geotrichum candidum, which is currently found in various environments, is widely used as ripening agent in some specific cheese making process. in order to optimize the cryopreservation of this microorganism, freezing experiments were carried out using a peltier cooler-heater incubator, which permits to control the temperature downshift from +20 to ...200717617397
directed evolution can rapidly improve the activity of chimeric assembly-line enzymes.nonribosomal peptides (nrps) are produced by nrp synthetase (nrps) enzymes that function as molecular assembly lines. the modular architecture of nrpss suggests that a domain responsible for activating a building block could be replaced with a domain from a foreign nrps to create a chimeric assembly line that produces a new variant of a natural nrp. however, such chimeric nrps modules are often heavily impaired, impeding efforts to create novel nrp variants by swapping domains from different mod ...200717620609
tomato mapks lempk1, lempk2, and lempk3 function in the systemin-mediated defense response against herbivorous insects.systemin is a wound-signaling peptide that mediates defenses of tomato plants against herbivorous insects. perception of systemin by the membrane-bound receptor sr160 results in activation of mapks, synthesis of jasmonic acid (ja), and expression of defense genes. to test the function of mapks in the response to systemin, we used virus-induced gene silencing (vigs) in plants that overexpress the systemin precursor prosystemin (35s::prosys plants). these transgenic plants accumulate high levels o ...200717623784
the pp2c-type phosphatase ap2c1, which negatively regulates mpk4 and mpk6, modulates innate immunity, jasmonic acid, and ethylene levels in arabidopsis.wound signaling pathways in plants are mediated by mitogen-activated protein kinases (mapks) and stress hormones, such as ethylene and jasmonates. in arabidopsis thaliana, the transmission of wound signals by mapks has been the subject of detailed investigations; however, the involvement of specific phosphatases in wound signaling is not known. here, we show that ap2c1, an arabidopsis ser/thr phosphatase of type 2c, is a novel stress signal regulator that inactivates the stress-responsive mapks ...200717630279
the arabidopsis bap1 and bap2 genes are general inhibitors of programmed cell death.here we identify the bap1 and bap2 genes of arabidopsis (arabidopsis thaliana) as general inhibitors of programmed cell death (pcd) across the kingdoms. these two homologous genes encode small proteins containing a calcium-dependent phospholipid-binding c2 domain. bap1 and its functional partner bon1 have been shown to negatively regulate defense responses and a disease resistance gene snc1. genetic studies here reveal an overlapping function of the bap1 and bap2 genes in cell death control. the ...200717631528
genetic and molecular requirements for function of the pto/prf effector recognition complex in tomato and nicotiana benthamiana.the pto gene of tomato (solanum lycopersicum) confers specific recognition of the unrelated bacterial effector proteins avrpto and avrptob. pto resides in a constitutive molecular complex with the nucleotide binding site-leucine rich repeats protein prf. prf is absolutely required for specific recognition of both effectors. here, using stable transgenic lines, we show that expression of pto from its genomic promoter in susceptible tomatoes was sufficient to complement recognition of pseudomonas ...200717635766
a bacterial e3 ubiquitin ligase targets a host protein kinase to disrupt plant immunity.many bacterial pathogens of plants and animals use a type iii secretion system to deliver diverse virulence-associated 'effector' proteins into the host cell. the mechanisms by which these effectors act are mostly unknown; however, they often promote disease by suppressing host immunity. one type iii effector, avrptob, expressed by the plant pathogen pseudomonas syringae pv. tomato, has a carboxy-terminal domain that is an e3 ubiquitin ligase. deletion of this domain allows an amino-terminal reg ...200717637671
crystal structure of the chromophore binding domain of an unusual bacteriophytochrome, rpbphp3, reveals residues that modulate photoconversion.bacteriophytochromes rpbphp2 and rpbphp3 from the photosynthetic bacterium rhodopseudomonas palustris work in tandem to modulate synthesis of the light-harvesting complex lh4 in response to light. although rpbphp2 and rpbphp3 share the same domain structure with 52% sequence identity, they demonstrate distinct photoconversion behaviors. rpbphp2 exhibits the "classical" phytochrome behavior of reversible photoconversion between red (pr) and far-red (pfr) light-absorbing states, whereas rpbphp3 ex ...200717640891
flagellin glycans from two pathovars of pseudomonas syringae contain rhamnose in d and l configurations in different ratios and modified 4-amino-4,6-dideoxyglucose.flagellins from pseudomonas syringae pv. glycinea race 4 and pseudomonas syringae pv. tabaci 6605 have been found to be glycosylated. glycosylation of flagellin is essential for bacterial virulence and is also involved in the determination of host specificity. flagellin glycans from both pathovars were characterized, and common sites of glycosylation were identified on six serine residues (positions 143, 164, 176, 183, 193, and 201). the structure of the glycan at serine 201 (s201) of flagellin ...200717644592
global analysis of mrna decay in halobacterium salinarum nrc-1 at single-gene resolution using dna microarrays.rna degradation is an important factor in the regulation of gene expression. it allows organisms to quickly respond to changing environmental conditions by adapting the expression of individual genes. the stability of individual mrnas within an organism varies considerably, contributing to differential amounts of proteins expressed. in this study we used dna microarrays to analyze mrna degradation in exponentially growing cultures of the extremely halophilic euryarchaeon halobacterium salinarum ...200717644597
host factors influencing susceptibility to hiv infection and aids progression.transmission of hiv first results in an acute infection, followed by an apparently asymptomatic period that averages ten years. in the absence of antiretroviral treatment, most patients progress into a generalized immune dysfunction that culminates in death. the length of the asymptomatic period varies, and in rare cases infected individuals never progress to aids. other individuals whose behavioral traits put them at high-risk of hiv transmission, surprisingly appear resistant and never succumb ...200717651505
the x-ray crystallographic structure and activity analysis of a pseudomonas-specific subfamily of the had enzyme superfamily evidences a novel biochemical function.the haloacid dehalogenase (had) superfamily is a large family of proteins dominated by phosphotransferases. thirty-three sequence families within the had superfamily (hadsf) have been identified to assist in function assignment. one such family includes the enzyme phosphoacetaldehyde hydrolase (phosphonatase). phosphonatase possesses the conserved rossmanniod core domain and a c1-type cap domain. other members of this family do not possess a cap domain and because the cap domain of phosphonatase ...200817654544
the pseudomonas putida lon protease is involved in n-acyl homoserine lactone quorum sensing regulation.in pseudomonas putida and pseduomonas aeruginosa, the similar ppur/rsal/ppui and lasr/rsal/lasi acyl homoserine lactones (ahls) quorum sensing (qs) systems have been shown to be under considerable regulation by other global regulators. a major regulator is the rsal protein which strongly directly represses the transcription of the p. putida ppui and p. aeruginosa lasi ahl synthases. in this study we screened a transposon mutant bank of p. putida in order to identify if any other regulators were ...200717655747
the plant host pathogen interface: cell wall and membrane dynamics of pathogen-induced responses.perception of pathogens by their hosts is the outcome of a highly coordinated and sophisticated surveillance network, tightly regulated by both host and pathogen elicitors, effectors, and signaling processes. in this article, we focus on two relatively well-studied host-pathogens systems, one involving a bacterial-plant interaction (pseudomonas syringae-arabidopsis) and the other involving an oomycete-plant interaction (phytophthora sojae-soybean). we discuss the status of current research relat ...200717656566
characterization of the osmoprotectant transporter opuc from pseudomonas syringae and demonstration that cystathionine-beta-synthase domains are required for its osmoregulatory function.the plant pathogen pseudomonas syringae may cope with osmotic stress on plants, in part, by importing osmoprotective compounds. in this study, we found that p. syringae pv. tomato strain dc3000 was distinct from most bacterial species in deriving greater osmoprotection from exogenous choline than from glycine betaine. this superior osmoprotection was correlated with a higher capacity for uptake of choline than for uptake of glycine betaine. of four putative osmoregulatory abc transporters in dc3 ...200717660277
salicylic acid, yersiniabactin, and pyoverdin production by the model phytopathogen pseudomonas syringae pv. tomato dc3000: synthesis, regulation, and impact on tomato and arabidopsis host plants.a genetically tractable model plant pathosystem, pseudomonas syringae pv. tomato dc3000 on tomato and arabidopsis thaliana hosts, was used to investigate the role of salicylic acid (sa) and iron acquisition via siderophores in bacterial virulence. pathogen-induced sa accumulation mediates defense in these plants, and dc3000 contains the genes required for the synthesis of sa, the sa-incorporated siderophore yersiniabactin (ybt), and the fluorescent siderophore pyoverdin (pvd). we found that dc30 ...200717660289
atnudt7, a negative regulator of basal immunity in arabidopsis, modulates two distinct defense response pathways and is involved in maintaining redox homeostasis.plants have evolved complicated regulatory systems to control immune responses. both positive and negative signaling pathways interplay to coordinate development of a resistance response with the appropriate amplitude and duration. atnudt7, a nudix domain-containing protein in arabidopsis (arabidopsis thaliana) that hydrolyzes nucleotide derivatives, was found to be a negative regulator of the basal defense response, and its loss-of-function mutation results in enhanced resistance to infection b ...200717660350
a novel insertion sequence, ispa26, in oprd of pseudomonas aeruginosa is associated with carbapenem resistance. 200717682099
identification of discriminative characteristics for clusters from biologic data with inforbio software.there are a number of different methods for generation of trees and algorithms for phylogenetic analysis in the study of bacterial taxonomy. genotypic information, such as ssu rrna gene sequences, now plays a more prominent role in microbial systematics than does phenotypic information. however, the integration of genotypic and phenotypic information for polyphasic studies is necessary for the classification and identification of microbes. thus, we devised an algorithm that objectively identifie ...200717683520
an "electronic fluorescent pictograph" browser for exploring and analyzing large-scale biological data sets.the exploration of microarray data and data from other high-throughput projects for hypothesis generation has become a vital aspect of post-genomic research. for the non-bioinformatics specialist, however, many of the currently available tools provide overwhelming amounts of data that are presented in a non-intuitive way.200717684564
the structural basis for activation of plant immunity by bacterial effector protein avrpto.pathogenic microbes use effectors to enhance susceptibility in host plants. however, plants have evolved a sophisticated immune system to detect these effectors using cognate disease resistance proteins, a recognition that is highly specific, often elicits rapid and localized cell death, known as a hypersensitive response, and thus potentially limits pathogen growth. despite numerous genetic and biochemical studies on the interactions between pathogen effector proteins and plant resistance prote ...200717694048
dual regulation role of gh3.5 in salicylic acid and auxin signaling during arabidopsis-pseudomonas syringae interaction.salicylic acid (sa) plays a central role in plant disease resistance, and emerging evidence indicates that auxin, an essential plant hormone in regulating plant growth and development, is involved in plant disease susceptibility. gh3.5, a member of the gh3 family of early auxin-responsive genes in arabidopsis (arabidopsis thaliana), encodes a protein possessing in vitro adenylation activity on both indole-3-acetic acid (iaa) and sa. here, we show that gh3.5 acts as a bifunctional modulator in bo ...200717704230
athipm, an ortholog of the apple hrpn-interacting protein, is a negative regulator of plant growth and mediates the growth-enhancing effect of hrpn in arabidopsis.hrpn (harpin) protein is critical to the virulence of the fire blight pathogen erwinia amylovora in host plants like apple (malus x domestica). moreover, exogenous treatment of arabidopsis (arabidopsis thaliana), a nonhost plant, with partially purified hrpn enhances growth. to address the bases of the effects of hrpn in disease, we sought a hrpn-interacting protein(s) in apple, using a yeast two-hybrid assay. a single positive clone, designated hipm (hrpn-interacting protein from malus), was fo ...200717704235
pseudomonas syringae type iii effector avrptob is phosphorylated in plant cells on serine 258, promoting its virulence activity.the pseudomonas syringae pv. tomato protein avrptob is translocated into plant cells via the bacterial type iii secretion system. in resistant tomato leaves, avrptob acts as an avirulence protein by interacting with the host pto kinase and eliciting the host immune response. pto-mediated immunity requires prf, a pto-interacting protein with a putative nucleotide-binding site and a region of leucine-rich repeats. in susceptible tomato plants, which lack either pto or prf, avrptob acts as a virule ...200717711844
characterization of arabidopsis thaliana genes encoding functional homologues of the yeast metal chaperone cox19p, involved in cytochrome c oxidase biogenesis.the arabidopsis thaliana genome contains two nearly identical genes which encode proteins showing similarity with the yeast metal chaperone cox19p, involved in cytochrome c oxidase biogenesis. one of these genes (atcox19-1) produces two transcript forms that arise from an alternative splicing event and encode proteins with different n-terminal portions. both atcox19 isoforms are imported into mitochondria in vitro and are found attached to the inner membrane facing the intermembrane space. the s ...200717712601
blue-light-activated histidine kinases: two-component sensors in bacteria.histidine kinases, used for environmental sensing by bacterial two-component systems, are involved in regulation of bacterial gene expression, chemotaxis, phototaxis, and virulence. flavin-containing domains function as light-sensory modules in plant and algal phototropins and in fungal blue-light receptors. we have discovered that the prokaryotes brucella melitensis, brucella abortus, erythrobacter litoralis, and pseudomonas syringae contain light-activated histidine kinases that bind a flavin ...200717717187
role of phages in the pathogenesis of burkholderia, or 'where are the toxin genes in burkholderia phages?'.most bacteria of the genus burkholderia are soil- and rhizosphere-associated, and rhizosphere associated, noted for their metabolic plasticity in the utilization of a wide range of organic compounds as carbon sources. many burkholderia species are also opportunistic human and plant pathogens, and the distinction between environmental, plant, and human pathogens is not always clear. burkholderia phages are not uncommon and multiple cryptic prophages are identifiable in the sequenced burkholderia ...200717719265
ethylene is one of the key elements for cell death and defense response control in the arabidopsis lesion mimic mutant vad1.although ethylene is involved in the complex cross talk of signaling pathways regulating plant defense responses to microbial attack, its functions remain to be elucidated. the lesion mimic mutant vad1-1 (for vascular associated death), which exhibits the light-conditional appearance of propagative hypersensitive response-like lesions along the vascular system, is a good model for studying the role of ethylene in programmed cell death and defense. here, we demonstrate that expression of genes as ...200717720753
inhibition of fungal and bacterial plant pathogens in vitro and in planta with ultrashort cationic lipopeptides.plant diseases constitute an emerging threat to global food security. many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and cause extended environmental pollution. moreover, an increasing number of phytopathogens develop resistance to them. recently, we have reported on a new family of ultrashort antimicrobial lipopeptides which are composed of only four amino acids linked to fatty acids (a. makovitzki, d. avrahami, and y. shai, proc. natl ...200717720828
molecular evolution of pathogenicity-island genes in pseudomonas viridiflava.the bacterial pathogen pseudomonas viridiflava possesses two pathogenicity islands (pais) that share many gene homologs, but are structurally and phenotypically differentiated (t-pai and s-pai). these pais are paralogous, but only one is present in each isolate. while this dual presence/absence polymorphism has been shown to be maintained by balancing selection, little is known about the molecular evolution of individual genes on the pais. here we investigate genetic variation of 12 pai gene loc ...200717720907
the phytotoxin coronatine contributes to pathogen fitness and is required for suppression of salicylic acid accumulation in tomato inoculated with pseudomonas syringae pv. tomato dc3000.the roles of the phytotoxin coronatine (cor) and salicylic acid (sa)-mediated defenses in the interaction of pseudomonas syringae pv. tomato dc3000 and tomato (solanum lycopersicum) were investigated. unlike findings reported for arabidopsis thaliana, dc3000 mutants impaired for production of cor or one of its components, coronafacic acid (cfa) or coronamic acid (cma), induced distinctly different disease lesion phenotypes in tomato. tomato plants inoculated with the cfa- cma- mutant db29 showed ...200717722699
the relationship of within-host multiplication and virulence in a plant-virus system.virulence does not represent any obvious advantage to parasites. most models of virulence evolution assume that virulence is an unavoidable consequence of within-host multiplication of parasites, resulting in trade-offs between within-host multiplication and between-host transmission fitness components. experimental support for the central assumption of this hypothesis, i.e., for a positive correlation between within-host multiplication rates and virulence, is limited for plant-parasite systems.200717726516
phosphatidylinositol as a component of the ice nucleating site of pseudomonas syringae and erwinia herbiola.phosphatidylinositol has been identified as a major component of the ice nucleating site on the outer surface of two bacteria, pseudomonas syringae and erwinia herbicola. plant lectins binding to inositol and a highly purified phosphatidylinositol-specific hydrolase (a c(ii) lipase) inhibited or decreased the efficiency of the ice nucleating activity (ina) of both bacteria. extracts of these two ina(+) bacteria had phosphatidylinositol synthase activity while extracts from related ina(-) pseudom ...198417759892
the n-terminal region of pseudomonas type iii effector avrptob elicits pto-dependent immunity and has two distinct virulence determinants.resistance to bacterial speck disease in tomato is activated by the physical interaction of the host pto kinase with either of the sequence-dissimilar type iii effector proteins avrpto or avrptob (hopab2) from pseudomonas syringae pv. tomato. pto-mediated immunity requires prf, a protein with a nucleotide-binding site and leucine-rich repeats. the n-terminal 307 amino acids of avrptob were previously reported to interact with the pto kinase, and we show here that this region (avrptob(1-307)) is ...200717764515
virulence and prodigiosin antibiotic biosynthesis in serratia are regulated pleiotropically by the ggdef/eal domain protein, pigx.gram-negative bacteria of the genus serratia are opportunistic human, plant, and insect pathogens. serratia sp. strain atcc 39006 secretes pectinases and cellulases and produces the secondary metabolites carbapenem and prodigiosin. mutation of a gene (pigx) resulted in an extremely pleiotropic phenotype: prodigiosin antibiotic biosynthesis, plant virulence, and pectinase production were all elevated. pigx controlled secondary metabolism by repressing the transcription of the target prodigiosin b ...200717766413
pseudomonas syringae lytic transglycosylases coregulated with the type iii secretion system contribute to the translocation of effector proteins into plant cells.pseudomonas syringae translocates virulence effector proteins into plant cells via a type iii secretion system (t3ss) encoded by hrp (for hypersensitive response and pathogenicity) genes. three genes coregulated with the hrp t3ss system in p. syringae pv. tomato dc3000 have predicted lytic transglycosylase domains: pspto1378 (here designated hrph), pspto2678 (hopp1), and pspto852 (hopaj1). hrph is located between hrpr and avre1 in the hrp pathogenicity island and is carried in the functional clu ...200717827286
physiological ecology of stenoxybacter acetivorans, an obligate microaerophile in termite guts.stenoxybacter acetivorans is a newly described, obligately microaerophilic beta-proteobacterium that is abundant in the acetate-rich hindgut of reticulitermes. here we tested the hypotheses that cells are located in the hypoxic, peripheral region of reticulitermes flavipes hindguts and use acetate to fuel their o(2)-consuming respiratory activity in situ. physical fractionation of r. flavipes guts, followed by limited-cycle pcr with s. acetivorans-specific 16s rrna gene primers, indicated that c ...200717827335
exoribonuclease r in mycoplasma genitalium can carry out both rna processing and degradative functions and is sensitive to rna ribose methylation.mycoplasma genitalium, a small bacterium having minimal genome size, has only one identified exoribonuclease, rnase r (mgr). we have purified mgr to homogeneity, and compared its rna degradative properties to those of its escherichia coli homologs rnase r (ecr) and rnase ii (ecii). mgr is active on a number of substrates including oligoribonucleotides, poly(a), rrna, and precursors to trna. unlike ecr, which degrades rrna and pre-trna without formation of intermediate products, mgr appears sensi ...200717872508
identification of harpins in pseudomonas syringae pv. tomato dc3000, which are functionally similar to hrpk1 in promoting translocation of type iii secretion system effectors.harpins are a subset of type iii secretion system (t3ss) substrates found in all phytopathogenic bacteria that utilize a t3ss. pseudomonas syringae pv. tomato dc3000 was previously reported to produce two harpins, hrpz1 and hrpw1. dc3000 was shown here to deploy two additional proteins, hopak1 and hopp1, which have the harpin-like properties of lacking cysteine, eliciting the hypersensitive response (hr) when partially purified and infiltrated into tobacco leaves, and possessing a two-domain str ...200717873033
the pseudomonas syringae type iii effector tyrosine phosphatase hopao1 suppresses innate immunity in arabidopsis thaliana.the bacterial pathogen pseudomonas syringae pv. tomato (pst) strain dc3000 infects tomato and arabidopsis plants, and is a model for studying the molecular basis of bacterial disease. pst dc3000 secretes a battery of largely uncharacterized effector proteins into host cells via a type-iii secretion system (ttss). little is currently known about the molecular mechanisms by which individual ttss effectors promote virulence. the effector hopao1 has similarity to protein tyrosine phosphatases, inclu ...200717877704
evaluation of reference genes for real-time rt-pcr expression studies in the plant pathogen pectobacterium atrosepticum.real-time rt-pcr has become a powerful technique to monitor low-abundance mrna expression and is a useful tool when examining bacterial gene expression inside infected host tissues. however, correct evaluation of data requires accurate and reliable normalisation against internal standards. thus, the identification of reference genes whose expression does not change during the course of the experiment is of paramount importance. here, we present a study where manipulation of cultural growth condi ...200717888160
the ralstonia solanacearum pathogenicity regulator hrpb induces 3-hydroxy-oxindole synthesis.the transcriptional activator hrpb of the bacterial wilt causing betaproteobacterium ralstonia solanacearum represents a key regulator for pathogenicity. in particular, it drives expression of hrp genes encoding a type iii secretion system (t3ss) as well as effector molecules for delivery into the host cytosol to promote disease. however, the hrpb regulon extends beyond this t3ss. we describe here an hrpb-activated operon of six genes that is responsible for the synthesis of a fluorescent isatin ...200717890323
a cluster of disease resistance genes in arabidopsis is coordinately regulated by transcriptional activation and rna silencing.the rpp5 (for recognition of peronospora parasitica 5) locus in the arabidopsis thaliana columbia strain contains a cluster of paralogous disease resistance (r) genes that play important roles in innate immunity. among the r genes in this locus, rpp4 confers resistance to two races of the fungal pathogen hyaloperonospora parasitica, while activation of snc1 (for suppressor of npr1-1, constitutive 1) results in the resistance to another race of h. parasitica and to pathovars of the bacterial path ...200717890374
rice pti1a negatively regulates rar1-dependent defense responses.tomato (solanum lycopersicum) pto encodes a protein kinase that confers resistance to bacterial speck disease. a second protein kinase, pti1, physically interacts with pto and is involved in pto-mediated defense signaling. pti1-related sequences are highly conserved among diverse plant species, including rice (oryza sativa), but their functions are largely unknown. here, we report the identification of a null mutant for the pti1 homolog in rice and the functional characterization of os pti1a. th ...200717890377
deinococcus geothermalis: the pool of extreme radiation resistance genes shrinks.bacteria of the genus deinococcus are extremely resistant to ionizing radiation (ir), ultraviolet light (uv) and desiccation. the mesophile deinococcus radiodurans was the first member of this group whose genome was completely sequenced. analysis of the genome sequence of d. radiodurans, however, failed to identify unique dna repair systems. to further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second deinococcus species, the thermophile de ...200717895995
wounding induces resistance to pathogens with different lifestyles in tomato: role of ethylene in cross-protection.many reports point to the existence of a network of regulatory signalling occurring in plants during the interaction with micro-organisms (biotic stress) and abiotic stresses such as wounding. however, the focus is on shared intermediates/components and/or common molecular outputs in differently triggered signalling pathways, and not on the degree and modes of effective influence between abiotic and biotic stresses nor the range of true plant-pathogen interactions open to such influence. we repo ...200717897407
distinct roles of the pepper hypersensitive induced reaction protein gene cahir1 in disease and osmotic stress, as determined by comparative transcriptome and proteome analyses.a capsicum annuum hypersensitive induced reaction protein1 (cahir1) was recently proposed as a positive regulator of hypersensitive cell death in plants. overexpression of cahir1 in transgenic arabidopsis plants conferred enhanced resistance against the hemi-biotrophic pseudomonas syringae pv. tomato (pst) and the biotrophic hyaloperonospora parasitica. infection by avirulent pseudomonas strains carrying avrrpm1 or avrrpt2 caused enhanced resistance responses in transgenic plants, suggesting tha ...200817899171
a blue light inducible two-component signal transduction system in the plant pathogen pseudomonas syringae pv. tomato.the open reading frame pspto2896 from the plant pathogen pseudomonas syringae pv. tomato encodes a protein of 534 amino acids showing all salient features of a blue light-driven two-component system. the n-terminal lov (light, oxygen, voltage) domain, potentially binding a flavin chromophore, is followed by a histidine kinase (hk) motif and a response regulator (rr). the full-length protein (pst-lov) and, separately, the rr and the lov+hk part (pst-lov(deltarr)) were heterologously expressed and ...200817905842
hydrogen peroxide generation by the pepper extracellular peroxidase capo2 activates local and systemic cell death and defense response to bacterial pathogens.reactive oxygen species (ros) are responsible for mediating cellular defense responses in plants. controversy has existed over the origin of ros in plant defense. we have isolated a novel extracellular peroxidase gene, capo2, from pepper (capsicum annuum). local or systemic expression of capo2 is induced in pepper by avirulent xanthomonas campestris pv vesicatoria (xcv) infection. we examined the function of the capo2 gene in plant defense using the virus-induced gene silencing technique and gai ...200717905862
linear osmoregulated periplasmic glucans are encoded by the opggh locus of pseudomonas aeruginosa.osmoregulated periplasmic glucans (opgs) are produced by many proteobacteria and are important for bacterial-host interactions. the opgg and opgh genes involved in the synthesis of opgs are the most widely distributed genes in proteobacterial genomes. two other non-homologous genes, both named ndvb, are also involved in opg biosynthesis in several species. the pseudomonas aeruginosa genome possesses two orfs, pa5077 and pa5078, that show similarity to opgh and opgg of pseudomonas syringae, respe ...200717906125
overexpression of arabidopsis map kinase kinase 7 leads to activation of plant basal and systemic acquired resistance.there is a growing body of evidence indicating that mitogen-activated protein kinase (mapk) cascades are involved in plant defense responses. analysis of the completed arabidopsis thaliana genome sequence has revealed the existence of 20 mapks, 10 mapkks and 60 mapkkks, implying a high level of complexity in mapk signaling pathways, and making the assignment of gene functions difficult. the map kinase kinase 7 (mkk7) gene of arabidopsis has previously been shown to negatively regulate polar auxi ...200717908155
medicinal smoke reduces airborne bacteria.this study represents a comprehensive analysis and scientific validation of our ancient knowledge about the effect of ethnopharmacological aspects of natural products' smoke for therapy and health care on airborne bacterial composition and dynamics, using the biolog microplate panels and microlog database. we have observed that 1h treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan sámagri=material used in oblation to fire all over india) ...200717913417
absence of the endo-beta-1,4-glucanases cel1 and cel2 reduces susceptibility to botrytis cinerea in tomato.cel1 and cel2 are members of the tomato (solanum lycopersicum mill) endo-beta-1,4-glucanase (egase) family that may play a role in fruit ripening and organ abscission. this work demonstrates that cel1 protein is present in other vegetative tissues and accumulates during leaf development. we recently reported the downregulation of both the cel1 mrna and protein upon fungal infection, suggesting the involvement of egases in plant-pathogen interactions. this hypothesis was confirmed by assessing th ...200717916112
a key role for the arabidopsis win3 protein in disease resistance triggered by pseudomonas syringae that secrete avrrpt2.effector proteins injected by the pathogenic bacteria pseudomonas syringae into plants can have profound effects on the pathogen-host interaction due to their efficient recognition by plants and the subsequent triggering of defenses. the avrrpt2 effector triggers strong local and systemic defense (called systemic acquired resistance [sar]) responses in arabidopsis thaliana plants that harbor a functional rps2 gene that encodes an r protein in the coiled-coil, nucleotide-binding domain, leucine-r ...200717918621
distribution and replication of the pathogenicity plasmid ppath in diverse populations of the gall-forming bacterium pantoea agglomerans.pantoea agglomerans has been transformed from a commensal bacterium into two related gall-forming pathovars by acquisition of ppath plasmids containing a pathogenicity island (pai). this pai harbors an hrp/hrc gene cluster, type iii effectors, and phytohormone biosynthetic genes. dna typing by pulsed-field gel electrophoresis revealed two major groups of p. agglomerans pv. gypsophilae and one group of p. agglomerans pv. betae. the ppath plasmids of the different groups had nearly identical repli ...200717921271
erwinia carotovora elicitors and botrytis cinerea activate defense responses in physcomitrella patens.vascular plants respond to pathogens by activating a diverse array of defense mechanisms. studies with these plants have provided a wealth of information on pathogen recognition, signal transduction and the activation of defense responses. however, very little is known about the infection and defense responses of the bryophyte, physcomitrella patens, to well-studied phytopathogens. the purpose of this study was to determine: i) whether two representative broad host range pathogens, erwinia carot ...200717922917
a novel relaxase homologue is involved in chromosomal dna processing for type iv secretion in neisseria gonorrhoeae.the neisseria gonorrhoeae type iv secretion system secretes chromosomal dna that acts in natural transformation. to examine the mechanism of dna processing for secretion, we made mutations in the putative relaxase gene trai and used nucleases to characterize the secreted dna. the nuclease experiments demonstrated that the secreted dna is single-stranded and blocked at the 5' end. mutation of trai identified tyr93 as required for dna secretion, while substitution of tyr201 resulted in intermediat ...200717927698
comparative and functional genomics reveals genetic diversity and determinants of host specificity among reference strains and a large collection of chinese isolates of the phytopathogen xanthomonas campestris pv. campestris.xanthomonas campestris pathovar campestris (xcc) is the causal agent of black rot disease of crucifers worldwide. the molecular genetic diversity and host specificity of xcc are poorly understood.200717927820
function of a novel gdsl-type pepper lipase gene, caglip1, in disease susceptibility and abiotic stress tolerance.gdsl-type lipase is a hydrolytic enzyme whose amino acid sequence contains a pentapeptide motif (gly-x-ser-x-gly) with active serine (ser). pepper gdsl-type lipase (caglip1) gene was isolated and functionally characterized from pepper leaf tissues infected by xanthomonas campestris pv. vesicatoria (xcv). the caglip1 protein was located in the vascular tissues of arabidopsis root. the caglip1 gene was preferentially expressed in pepper leaves during the compatible interaction with xcv. treatment ...200817929052
arabidopsis atg6 is required to limit the pathogen-associated cell death response.to begin to understand the interplay between autophagy and the hypersensitive response (hr), a type of programmed cell death (pcd) induced during plant innate immunity, we generated atg6 antisense plants in the genetically tractable arabidopsis thaliana system. atatg6 antisense (atatg6-as) plants senesce early and are sensitive to nutrient starvation, suggestive of impairment of autophagic function in these plants. additionally, these plants exhibited multiple developmental abnormalities, a phen ...200817932459
burkholderia cenocepacia c5424 produces a pigment with antioxidant properties using a homogentisate intermediate.burkholderia cenocepacia is a gram-negative opportunistic pathogen that belongs to the burkholderia cepacia complex. b. cenocepacia can survive intracellularly within phagocytic cells, and some epidemic strains produce a brown melanin-like pigment that can scavenge free radicals, resulting in the attenuation of the host cell oxidative burst. in this work, we demonstrate that the brown pigment produced by b. cenocepacia c5424 is synthesized from a homogentisate (hga) precursor. the disruption of ...200717933889
the arabidopsis mitogen-activated protein kinase kinase mkk3 is upstream of group c mitogen-activated protein kinases and participates in pathogen signaling.although the arabidopsis thaliana genome contains genes encoding 20 mitogen-activated protein kinases (mapks) and 10 mapk kinases (mapkks), most of them are still functionally uncharacterized. in this work, we analyzed the function of the group b mapk kinase, mkk3. transgenic promkk3:gus lines showed basal expression in vascular tissues that was strongly induced by pseudomonas syringae pv tomato strain dc3000 (pst dc3000) infection but not by abiotic stresses. the growth of virulent pst dc3000 w ...200717933903
anti-ice nucleation activity in xylem extracts from trees that contain deep supercooling xylem parenchyma cells.boreal hardwood species, including japanese white birch (betula platyphylla sukat. var. japonica hara), japanese chestnut (castanea crenata sieb. et zucc.), katsura tree (cercidiphyllum japonicum sieb. et zucc.), siebold's beech (fagus crenata blume), mulberry (morus bombycis koidz.), and japanese rowan (sorbus commixta hedl.), had xylem parenchyma cells (xpcs) that adapt to subfreezing temperatures by deep supercooling. crude extracts from xylem in all these trees were found to have anti-ice nu ...200717936742
cloning and characterization of the biosynthetic gene cluster for kutznerides.kutznerides, actinomycete-derived cyclic depsipetides, consist of six nonproteinogenic residues, including a highly oxygenated tricyclic hexahydropyrroloindole, a chlorinated piperazic acid, 2-(1-methylcyclopropyl)-glycine, a beta-branched-hydroxy acid, and 3-hydroxy glutamic acid, for which biosynthetic logic has not been elucidated. herein we describe the biosynthetic gene cluster for the kutzneride family, identified by degenerate primer pcr for halogenating enzymes postulated to be involved ...200717940045
avrac(xcc8004), a type iii effector with a leucine-rich repeat domain from xanthomonas campestris pathovar campestris confers avirulence in vascular tissues of arabidopsis thaliana ecotype col-0.xanthomonas campestris pathovar campestris causes black rot, a vascular disease on cruciferous plants, including arabidopsis thaliana. the gene xc1553 from x. campestris pv. campestris strain 8004 encodes a protein containing leucine-rich repeats (lrrs) and appears to be restricted to strains of x. campestris pv. campestris. lrrs are found in a number of type iii-secreted effectors in plant and animal pathogens. these prompted us to investigate the role of the xc1553 gene in the interaction betw ...200817951377
avrac(xcc8004), a type iii effector with a leucine-rich repeat domain from xanthomonas campestris pathovar campestris confers avirulence in vascular tissues of arabidopsis thaliana ecotype col-0.xanthomonas campestris pathovar campestris causes black rot, a vascular disease on cruciferous plants, including arabidopsis thaliana. the gene xc1553 from x. campestris pv. campestris strain 8004 encodes a protein containing leucine-rich repeats (lrrs) and appears to be restricted to strains of x. campestris pv. campestris. lrrs are found in a number of type iii-secreted effectors in plant and animal pathogens. these prompted us to investigate the role of the xc1553 gene in the interaction betw ...200817951377
identification of two gene clusters and a transcriptional regulator required for pseudomonas aeruginosa glycine betaine catabolism.glycine betaine (gb), which occurs freely in the environment and is an intermediate in the catabolism of choline and carnitine, can serve as a sole source of carbon or nitrogen in pseudomonas aeruginosa. twelve mutants defective in growth on gb as the sole carbon source were identified through a genetic screen of a nonredundant pa14 transposon mutant library. further growth experiments showed that strains with mutations in two genes, gbca (pa5410) and gbcb (pa5411), were capable of growth on dim ...200817951379
identification of two gene clusters and a transcriptional regulator required for pseudomonas aeruginosa glycine betaine catabolism.glycine betaine (gb), which occurs freely in the environment and is an intermediate in the catabolism of choline and carnitine, can serve as a sole source of carbon or nitrogen in pseudomonas aeruginosa. twelve mutants defective in growth on gb as the sole carbon source were identified through a genetic screen of a nonredundant pa14 transposon mutant library. further growth experiments showed that strains with mutations in two genes, gbca (pa5410) and gbcb (pa5411), were capable of growth on dim ...200817951379
alternative splicing and mrna levels of the disease resistance gene rps4 are induced during defense responses.the arabidopsis (arabidopsis thaliana) disease resistance protein resistance to pseudomonas syringae4 (rps4) activates defenses in response to bacterial pathogens expressing avrrps4 in a gene-for-gene specific manner. the rps4 gene produces multiple transcripts via alternative splicing of two regular introns flanking exon 3 and a cryptic intron within exon 3. we showed previously that rps4-mediated resistance requires the combined presence of transcripts encoding both full-length and truncated o ...200717951452
oxo-phytodienoic acid-containing galactolipids in arabidopsis: jasmonate signaling dependence.the jasmonate family of phytohormones, as represented by 12-oxo-phytodienoic acid (opda), dinor-phytodienoic acid (dn-opda), and jasmonic acid in arabidopsis (arabidopsis thaliana), has been implicated in a vast array of different developmental processes and stress responses. recent reports indicate that opda and dn-opda occur not only as free acids in arabidopsis, but also as esters with complex lipids, so-called arabidopsides. recently, we showed that recognition of the two bacterial effector ...200717951463
the plant growth-promoting fungus penicillium simplicissimum gp17-2 induces resistance in arabidopsis thaliana by activation of multiple defense signals.arabidopsis thaliana grown in soil amended with barley grain inocula of penicillium simplicissimum gp17-2 or receiving root treatment with its culture filtrate (cf) exhibited clear resistance to pseudomonas syringae pv. tomato dc3000 (pst). to assess the contribution of different defense pathways, arabidopsis genotypes implicated in salicylic acid (sa) signaling expressing the nahg transgene or carrying disruption in npr1 (npr1), jasmonic acid (ja) signaling (jar1) and ethylene (et) signaling (e ...200717956859
functional analysis of polyphenol oxidases by antisense/sense technology.polyphenol oxidases (ppos) catalyze the oxidation of phenolics to quinones, the secondary reactions of which lead to oxidative browning and postharvest losses of many fruits and vegetables. ppos are ubiquitous in angiosperms, are inducible by both biotic and abiotic stresses, and have been implicated in several physiological processes including plant defense against pathogens and insects, the mehler reaction, photoreduction of molecular oxygen by psi, regulation of plastidic oxygen levels, auron ...200717960074
induction of a small heat shock protein and its functional roles in nicotiana plants in the defense response against ralstonia solanacearum.in tobacco (nicotiana tabacum), ralstonia solanacearum oe1-1 (rsoe1-1) is pathogenic, whereas r. solanacearum 8107 (rs8107) is nonpathogenic and induces the hypersensitive response (hr). to elucidate the molecular mechanisms of plant-r. solanacearum interactions, we used differential display to isolate a cdna fragment, a6, regulated in tobacco by inoculation with rsoe1-1. the deduced amino acid sequence predicted from full-length a6-cdna showed similarity to small heat shock proteins from arabid ...200717965181
novel hexamerization motif is discovered in a conserved cytoplasmic protein from salmonella typhimurium.the cytoplasmic protein stm3548 of unknown function obtained from a strain of salmonella typhimurium was determined by x-ray crystallography at a resolution of 2.25 a. the asymmetric unit contains a hexamer of structurally identical monomers. the monomer is a globular domain with a long beta-hairpin protrusion that distinguishes this structure. this beta-hairpin occupies a central position in the hexamer, and its residues participate in the majority of interactions between subunits of the hexame ...200717968677
high-throughput quantitative luminescence assay of the growth in planta of pseudomonas syringae chromosomally tagged with photorhabdus luminescens luxcdabe.bioluminescent strains of the arabidopsis thaliana pathogens pseudomonas syringae pathovar (pv.) tomato and pv. maculicola were made by insertion of the luxcdabe operon from photorhabdus luminescens into the p. syringae chromosome under the control of a constitutive promoter. stable integration of luxcdabe did not affect bacterial fitness, growth in planta or disease outcome. luminescence accurately and reliably reported bacterial growth in infected arabidopsis leaves both with a fixed inoculum ...200817971037
comparative genomic analysis of two-component regulatory proteins in pseudomonas syringae.pseudomonas syringae is a widespread bacterial plant pathogen, and strains of p. syringae may be assigned to different pathovars based on host specificity among different plant species. the genomes of p. syringae pv. syringae (psy) b728a, pv. tomato (pto) dc3000 and pv. phaseolicola (pph) 1448a have been recently sequenced providing a major resource for comparative genomic analysis. a mechanism commonly found in bacteria for signal transduction is the two-component system (tcs), which typically ...200717971244
sensitivity and speed of induced defense of cabbage (brassica oleracea l.): dynamics of bolox expression patterns during insect and pathogen attack.the lipoxygenase pathway is involved in the early steps of plant responses to herbivorous insects and phytopathogens. induced defenses in the crucifer brassica oleracea have been well documented. here, we have cloned a lipoxygenase (lox) from b. oleracea (bolox). the sequence reveals that the bolox protein has a transit peptide for chloroplast targeting, which is characteristic for class 2 loxs involved in jasmonic acid (ja) biosynthesis which takes place in the chloroplast. phylogenetic analysi ...200717977145
basal resistance against pseudomonas syringae in arabidopsis involves wrky53 and a protein with homology to a nematode resistance protein.basal resistance is the ultimately unsuccessful plant defense response to infection with a virulent pathogen. it is thought to be triggered by host recognition of pathogen-associated molecular patterns, with subsequent suppression of particular components by pathogen effectors. to identify novel components of arabidopsis basal resistance against the bacterial pathogen pseudomonas syringae pv. tomato, microarray expression profiling was carried out on the cirl mutant, which displays enhanced resi ...200717977154
induction of p-coumaroyldopamine and feruloyldopamine, two novel metabolites, in tomato by the bacterial pathogen pseudomonas syringae.inoculation of tomato plants (solanum lycopersicum cv. rutgers) with pseudomonas syringae pv. tomato led to the production of a hypersensitive-like response in this pathovar of tomato. accumulation of hydroxycinnamic acid amides (hcaa) of tyramine (p-coumaroyltyramine and feruloyltyramine) and dopamine (p-coumaroyldopamine and feruloyldopamine) was detected after bacterial infection. two of them, p-coumaroyldopamine and feruloyldopamine, are described for the first time. the accumulation of hcaa ...200717977155
a library of linear undecapeptides with bactericidal activity against phytopathogenic bacteria.a 125-member library of synthetic linear undecapeptides was prepared based on a previously described peptide h-k(1)klfkkilkf(10)l-nh(2) (bp76) that inhibited in vitro growth of the plant pathogenic bacteria erwinia amylovora, xanthomonas axonopodis pv. vesicatoria, and pseudomonas syringae pv. syringae at low micromolar concentrations. peptides were designed using a combinatorial chemistry approach by incorporating amino acids possessing various degrees of hydrophobicity and hydrophilicity at po ...200717980935
novel candidate virulence factors in rice pathogen xanthomonas oryzae pv. oryzicola as revealed by mutational analysis.bacterial leaf streak, caused by xanthomonas oryzae pv. oryzicola, is an important disease of rice. transposon-mediated mutational analysis of the pathogen with a quantitative assay revealed candidate virulence factors including genes involved in the pathogenesis of other phytopathogenic bacteria, virulence factors of animal pathogens, and genes not previously associated with virulence.200717981946
the nlee/ospz family of effector proteins is required for polymorphonuclear transepithelial migration, a characteristic shared by enteropathogenic escherichia coli and shigella flexneri infections.enteropathogenic escherichia coli (epec) and shigella flexneri are human host-specific pathogens that infect intestinal epithelial cells. however, each bacterial species employs a different infection strategy within this environmental niche. epec attaches to the apical surface of small intestine enterocytes, causing microvillus effacement and rearrangement of the host cell cytoskeleton beneath adherent bacteria. in contrast, s. flexneri invades the large intestine epithelium at the basolateral m ...200817984206
the nlee/ospz family of effector proteins is required for polymorphonuclear transepithelial migration, a characteristic shared by enteropathogenic escherichia coli and shigella flexneri infections.enteropathogenic escherichia coli (epec) and shigella flexneri are human host-specific pathogens that infect intestinal epithelial cells. however, each bacterial species employs a different infection strategy within this environmental niche. epec attaches to the apical surface of small intestine enterocytes, causing microvillus effacement and rearrangement of the host cell cytoskeleton beneath adherent bacteria. in contrast, s. flexneri invades the large intestine epithelium at the basolateral m ...200817984206
a photosensory two-component system regulates bacterial cell attachment.flavin-binding lov domains are blue-light photosensory modules that are conserved in a number of developmental and circadian regulatory proteins in plants, algae, and fungi. lov domains are also present in bacterial genomes, and are commonly located at the amino termini of sensor histidine kinases. genes predicted to encode lov-histidine kinases are conserved across a broad range of bacterial taxa, from aquatic oligotrophs to plant and mammalian pathogens. however, the function of these putative ...200717986614
histone h2a.z and homologues of components of the swr1 complex are required to control immunity in arabidopsis.one of the mechanisms involved in chromatin remodelling is so-called 'histone replacement'. an example of such a mechanism is the substitution of canonical h2a histone by the histone variant h2a.z. the atp-dependent chromatin remodelling complex swr1 is responsible for this action in yeast. we have previously proposed the existence of an swr1-like complex in arabidopsis by demonstrating genetic and physical interaction of the components sef, arp6 and pie1, which are homologues of the yeast swc6 ...200817988222
identification, expression analysis and characterization of defense and signaling genes in vitis vinifera.the reduction of phytochemicals applied to grapevine relies on the development of alternative strategies involving activation of the plant's own defense system. the aim of this work was to study the signaling of defense responses to pathogens in vitis vinifera. we identified in v. vinifera cv. chardonnay two putative regulatory elements, vvnhl1 and vveds1, with similarity to arabidopsis defense regulators ndr1 and eds1. expression studies of these putative signaling genes together with other kno ...200817988883
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