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gene expression changes linked to antimicrobial resistance, oxidative stress, iron depletion and retained motility are observed when burkholderia cenocepacia grows in cystic fibrosis sputum.bacteria from the burkholderia cepacia complex (bcc) are the only group of cystic fibrosis (cf) respiratory pathogens that may cause death by an invasive infection known as cepacia syndrome. their large genome (> 7000 genes) and multiple pathways encoding the same putative functions make virulence factor identification difficult in these bacteria.200818801206
the crystal structure of mexr from pseudomonas aeruginosa in complex with its antirepressor armr.the intrinsic antimicrobial resistance of the opportunistic human pathogen pseudomonas aeruginosa is compounded in mutant strains that overexpress multidrug efflux pumps such as the prominent drug-proton antiporter, mexab-oprm. the primary regulator of the mexab-oprm operon is the marr family repressor, mexr. an additional repressor, nalc, also regulates mexab-oprm by controlling expression of armr, an antirepressor peptide that is hypothesized to prevent the binding of mexr to its cognate dna o ...200818812515
fe(ii)/alpha-ketoglutarate hydroxylases involved in nucleobase, nucleoside, nucleotide, and chromatin metabolism.fe(ii)/alpha-ketoglutarate-dependent hydroxylases uniformly possess a double-stranded beta-helix fold with two conserved histidines and one carboxylate coordinating their mononuclear ferrous ions. oxidative decomposition of the alpha-keto acid is proposed to generate a ferryl-oxo intermediate capable of hydroxylating unactivated carbon atoms in a myriad of substrates. this perspective focuses on a subgroup of these enzymes that are involved in pyrimidine salvage, purine decomposition, nucleoside ...200818813363
isolation of a novel mutated strain of xanthomonas campestris for xanthan production using whey as the sole substrate.this study was conducted to isolate novel lactose utilizing xanthomonas campestris mutants. such a mutant will assist the utilization of whey as the sole carbon source for xanthan gum production, lower costs of fermentation process and set a precise application for whey as a waste. in this study, a mutant strain (na1) was isolated from xanthomonas campestris cells exposed to nitrous acid mutagenesis environmental conditions were optimized and maximum activity of the beta-galactosidase enzyme was ...200818817169
dipeptidyl aminopeptidase iv from stenotrophomonas maltophilia exhibits activity against a substrate containing a 4-hydroxyproline residue.the crystal structure of dipeptidyl aminopeptidase iv from stenotrophomonas maltophilia was determined at 2.8-a resolution by the multiple isomorphous replacement method, using platinum and selenomethionine derivatives. the crystals belong to space group p4(3)2(1)2, with unit cell parameters a = b = 105.9 a and c = 161.9 a. dipeptidyl aminopeptidase iv is a homodimer, and the subunit structure is composed of two domains, namely, n-terminal beta-propeller and c-terminal catalytic domains. at the ...200818820015
an efficient method for visualization and growth of fluorescent xanthomonas oryzae pv. oryzae in planta.xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight disease, is a serious pathogen of rice. here we describe a fluorescent marker system to study virulence and pathogenicity of x. oryzae pv. oryzae.200818826644
in silico comparison of transcript abundances during arabidopsis thaliana and glycine max resistance to fusarium virguliforme.sudden death syndrome (sds) of soybean (glycine max l. merr.) is an economically important disease, caused by the semi-biotrophic fungus fusarium solani f. sp. glycines, recently renamed fusarium virguliforme (fv). due to the complexity and length of the soybean-fusarium interaction, the molecular mechanisms underlying plant resistance and susceptibility to the pathogen are not fully understood. f. virguliforme has a very wide host range for the ability to cause root rot and a very narrow host r ...200818831797
the hrp genes of pseudomonas cichorii are essential for pathogenicity on eggplant but not on lettuce.pseudomonas cichorii causes necrotic lesions in eggplant and rot in lettuce. through transposon insertion into p. cichorii strain spc9018 we produced two mutants, 4-57 and 2-99, that lost virulence on eggplant but not lettuce. analyses showed that a transposon was inserted into the hrpg gene in 4-57 and the hrct gene in 2-99. nucleotide sequences of the hrp genes of spc9018 are homologous to those of pseudomonas viridiflava bs group strains. the pathogenicity of 4-57 on eggplant was restored by ...200818832299
cross-reaction of stenotrophomonas and xanthomonas species in a 23s rrna gene-directed pcr for detection of s. maltophilia. 200818842940
improvement of the thermostability and activity of a pectate lyase by single amino acid substitutions, using a strategy based on melting-temperature-guided sequence alignment.in the vast number of random mutagenesis experiments that have targeted protein thermostability, single amino acid substitutions that increase the apparent melting temperature (tm) of the enzyme more than 1 to 2 degrees c are rare and often require the creation of a large library of mutated genes. here we present a case where a single beneficial mutation (r236f) of a hemp fiber-processing pectate lyase of xanthomonas campestris origin (pl(xc)) produced a 6 degrees c increase in tm and a 23-fold ...200818156340
improvement of the thermostability and activity of a pectate lyase by single amino acid substitutions, using a strategy based on melting-temperature-guided sequence alignment.in the vast number of random mutagenesis experiments that have targeted protein thermostability, single amino acid substitutions that increase the apparent melting temperature (tm) of the enzyme more than 1 to 2 degrees c are rare and often require the creation of a large library of mutated genes. here we present a case where a single beneficial mutation (r236f) of a hemp fiber-processing pectate lyase of xanthomonas campestris origin (pl(xc)) produced a 6 degrees c increase in tm and a 23-fold ...200818156340
mesosome formation is accompanied by hydrogen peroxide accumulation in bacteria during the rifampicin effect.ultrastructural alteration and hydrogen peroxide localization were examined in xanthomonas campestris pv. phaseoli during rifampicin effect using transmission electron microscopy. bacterial cells were treated with rifampicin and then were examined by electron microscopy to observe the changes of ultrastructure or hydrogen peroxide accumulation in living cells that took place before lysis. intriguingly, rifampicin treatment led to presence of an additional location of hydrogen peroxide accumulati ...200818163201
regulation of the type ii secretion structural gene xpse in xanthomonas campestris pathovar campestris by the global transcription regulator clp.gspe is an important component of the type ii secretion system (t2ss) in gram-negative bacteria that supplies energy for the process of protein secretion. the role of gspe and its interactions with other components have been intensively studied. however, regulation of the gspe gene is poorly understood. in this study, we demonstrated that the transcription of xpse, a homologue of gspe in xanthomonas campestris pathovar campestris (xcc), is upregulated by clp, a homologue of the cyclic amp-recept ...200818175178
horizontal gene transfer and the evolution of transcriptional regulation in escherichia coli.most bacterial genes were acquired by horizontal gene transfer from other bacteria instead of being inherited by continuous vertical descent from an ancient ancestor. to understand how the regulation of these acquired genes evolved, we examined the evolutionary histories of transcription factors and of regulatory interactions from the model bacterium escherichia coli k12.200818179685
the crystal structure of n-acetyl-l-glutamate synthase from neisseria gonorrhoeae provides insights into mechanisms of catalysis and regulation.the crystal structures of n-acetylglutamate synthase (nags) in the arginine biosynthetic pathway of neisseria gonorrhoeae complexed with acetyl-coa and with coa plus n-acetylglutamate have been determined at 2.5- and 2.6-a resolution, respectively. the monomer consists of two separately folded domains, an amino acid kinase (aak) domain and an n-acetyltransferase (nat) domain connected through a 10-a linker. the monomers assemble into a hexameric ring that consists of a trimer of dimers with 32-p ...200818184660
activation of the indole-3-acetic acid-amido synthetase gh3-8 suppresses expansin expression and promotes salicylate- and jasmonate-independent basal immunity in rice.new evidence suggests a role for the plant growth hormone auxin in pathogenesis and disease resistance. bacterial infection induces the accumulation of indole-3-acetic acid (iaa), the major type of auxin, in rice (oryza sativa). iaa induces the expression of expansins, proteins that loosen the cell wall. loosening the cell wall is key for plant growth but may also make the plant vulnerable to biotic intruders. here, we report that rice gh3-8, an auxin-responsive gene functioning in auxin-depende ...200818192436
the xanthomonas oryzae pv. oryzae phopq two-component system is required for avrxa21 activity, hrpg expression, and virulence.the rice pathogen recognition receptor, xa21, confers resistance to xanthomonas oryzae pv. oryzae strains producing the type one system-secreted molecule, avrxa21. x. oryzae pv. oryzae requires a regulatory two-component system (tcs) called raxrh to regulate expression of eight rax (required for avrxa21 activity) genes and to sense population cell density. to identify other key components in this critical regulatory circuit, we assayed proteins expressed in a raxr gene knockout strain. this surv ...200818203830
identification and organization of genes for diutan polysaccharide synthesis from sphingomonas sp. atcc 53159.a cluster of genes for diutan polysaccharide synthesis was isolated from a library of sphingomonas sp. atcc 53159 genomic dna by complementation of glucosyl-isoprenylphosphate transferase-deficient mutants of sphingomonas elodea atcc 31461 (producing gellan) and xanthomonas campestris (producing xanthan). the synthesis of polysaccharide in these strains shares a common first step, transfer of glucose-1-phosphate from udp-glucose to the isoprenylphosphate lipid. the cluster of 24 genes was compar ...200818210176
further characterization of vibrio vulnificus rugose variants and identification of a capsular and rugose exopolysaccharide gene cluster.capsular polysaccharide (cps) is a major virulence factor in vibrio vulnificus, and encapsulated strains have an opaque, smooth (ops) colony morphology, while nonencapsulated strains have a translucent, smooth (trs) colony morphology. previously, we showed that ops and trs parental strains can yield a third colony type, rugose (r), and that the resulting strains, with the opr and trr phenotypes, respectively, form copious biofilms. here we show that while opr and trr strains both produce three-d ...200818212074
induction of l1 and l2 beta-lactamase production in stenotrophomonas maltophilia is dependent on an ampr-type regulator.a divergently oriented ampr has been located upstream of blal2 in stenotrophomonas maltophilia. ampr is necessary for l1 and l2 beta-lactamase induction in response to beta-lactam challenge, and activation of ampr is sufficient to induce l1 and l2 production. l1 induction requires more activation of ampr than does l2 induction.200818212097
molecular cloning and characterization of ghnpr1, a gene implicated in pathogen responses from cotton (gossypium hirsutum l.).a novel gene, designated as ghnpr1 (gossypium hirsutum non-expressor of pathogenesis-related genes 1), was isolated from g. hirsutum (cotton) by rt-pcr (reverse transcription-pcr) and race (rapid amplification of cdna ends). the full-length cdna was 2108 bp long and had an orf (open reading frame) that putatively encoded a polypeptide of 592 amino acids, with a predicted molecular mass of 66 kda. comparison of this protein sequence with that of arabidopsis thaliana, brassica juncea and nicotiana ...200818215146
predicting the interactome of xanthomonas oryzae pathovar oryzae for target selection and db service.protein-protein interactions (ppis) play key roles in various cellular functions. in addition, some critical inter-species interactions such as host-pathogen interactions and pathogenicity occur through ppis. phytopathogenic bacteria infect hosts through attachment to host tissue, enzyme secretion, exopolysaccharides production, toxins release, iron acquisition, and effector proteins secretion. many such mechanisms involve some kind of protein-protein interaction in hosts. our first aim was to p ...200818215330
a novel dsf-like signal from burkholderia cenocepacia interferes with candida albicans morphological transition.in addition to producing lethal antibiotics, microorganisms may also use a new form of antagonistic mechanism in which signal molecules are exported to influence the gene expression and hence the ecological competence of their competitors. we report here the isolation and characterization of a novel signaling molecule, cis-2-dodecenoic acid (bdsf), from burkholderia cenocepacia. bdsf is structurally similar to the diffusible signal factor (dsf) that is produced by the rpff enzyme of xanthomonas ...200818049456
protein-protein interactions within type iii secretion system-dependent pili of rhizobium sp. strain ngr234.pili synthesized by the type iii secretion system of rhizobium species strain ngr234 are essential for protein secretion and thus for efficient symbiosis with many legumes. isolation and partial purification of these pili showed that they are composed of at least three proteins, nopa, nopb, and nopx. using biochemical assays, we show here that these proteins interact directly with one another.200817981961
protein-protein interactions within type iii secretion system-dependent pili of rhizobium sp. strain ngr234.pili synthesized by the type iii secretion system of rhizobium species strain ngr234 are essential for protein secretion and thus for efficient symbiosis with many legumes. isolation and partial purification of these pili showed that they are composed of at least three proteins, nopa, nopb, and nopx. using biochemical assays, we show here that these proteins interact directly with one another.200817981961
the crystal structure of a binary complex of two pseudopilins: epsi and epsj from the type 2 secretion system of vibrio vulnificus.type ii secretion systems (t2ss) translocate virulence factors from the periplasmic space of many pathogenic bacteria into the extracellular environment. the t2ss of vibrio cholerae and related species is called the extracellular protein secretion (eps) system that consists of a core of multiple copies of 11 different proteins. the pseudopilins, epsg, epsh, epsi, epsj and epsk, are five t2ss proteins that are thought to assemble into a pseudopilus, which is assumed to interact with the outer mem ...200818022192
the crystal structure of a binary complex of two pseudopilins: epsi and epsj from the type 2 secretion system of vibrio vulnificus.type ii secretion systems (t2ss) translocate virulence factors from the periplasmic space of many pathogenic bacteria into the extracellular environment. the t2ss of vibrio cholerae and related species is called the extracellular protein secretion (eps) system that consists of a core of multiple copies of 11 different proteins. the pseudopilins, epsg, epsh, epsi, epsj and epsk, are five t2ss proteins that are thought to assemble into a pseudopilus, which is assumed to interact with the outer mem ...200818022192
biosynthesis of dtdp-3-acetamido-3,6-dideoxy-alpha-d-glucose.derivatives of 3-amino-3,6-dideoxyhexoses are widespread in nature. they are part of the repeating units of lipopolysaccharide o-antigens, of the glycan moiety of s-layer (bacterial cell surface layer) glycoproteins and also of many antibiotics. in the present study, we focused on the elucidation of the biosynthesis pathway of dtdp-alpha-d-quip3nac (dtdp-3-acetamido-3,6-dideoxy-alpha-d-glucose) from the gram-positive, anaerobic, thermophilic organism thermoanaerobacterium thermosaccharolyticum e ...200817941826
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
the mutagenic properties of brdutp in a random mutagenesis process.to explore the mutagenic properties of the nucleotide analogue bromodeoxyuridine triphosphate (brdutp), the wild type alpha-amylase (xamy) gene from xanthomonas campestris pv. campestris 8004 was used as a mutational target. it was mutated using pcr techniques to partially replace deoxythymidine triphosphate (dttp) with brdutp. a total of 18 mutants were selected for dna sequencing from the mutagenesis libraries by their ability to hydrolyze the starch. the results showed that 70% of the total m ...200817874205
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
sensitive and specific detection of xanthomonas campestris pv. vesicatoria by pcr using pathovar-specific primers based on rhs family gene sequences.the present study describes pcr assay to detect bacterial spot caused by xanthomonas campestris pv. vesicatoria in pepper and tomato. one set of pcr primer was developed to amplify gene required for an rhs family gene homologous to rhsa, cell envelope biogenesis, outer membrane. only a pcr product of a 517bp was produced in pcr reaction with the xanthomonas campestris pv. vesicatoria (xcvf/xcvr) primer set. a specific, and highly sensitive and rapid pcr assay for the detection of x. campestris p ...200917317128
a novel patatin-like protein from cotton plant, ghpat1, is co-expressed with ghlox1 during xanthomonas campestris-mediated hypersensitive cell death.in cotton plant, xanthomonas-induced hypersensitive response (hr) is accompanied by a lipid peroxidation process involving a 9-lipoxygenase (lox), ghlox1. initiation of this oxidative metabolism implies the release of the lox substrates, or polyunsaturated fatty acids. since patatin-like proteins (plps) are likely candidates for mediating the latter step, we searched for genes encoding such enzymes, identified and cloned one of them that we named ghpat1. biochemical and molecular studies showed ...200918850102
mutational analysis of the gum gene cluster required for xanthan biosynthesis in xanthomonas oryzae pv oryzae.genome sequence analysis of xanthomonas oryzae pv. oryzae has revealed a cluster of 12 orfs that are closely related to the gum gene cluster of xanthomonas campestris pv. campestris. the gum gene cluster of x. oryzae encodes proteins involved in xanthan production; however, there is little experimental evidence supporting this. in this study, biochemical analyses of xanthan produced by a defined set of x. oryzae gum mutant strains allowed us to preliminarily assign functions to most of the gum g ...200918854951
metagenome-derived clones encoding two novel lactonase family proteins involved in biofilm inhibition in pseudomonas aeruginosa.here we report the isolation and characterization of three metagenome-derived clones that interfere with bacterial quorum sensing and degrade n-(3-oxooctanoyl)-l-homoserine lactone (3-oxo-c(8)-hsl). by using a trai-lacz gene fusion, the metagenome-derived clones were identified from a soil dna library and analyzed. the open reading frames linked to the 3-oxo-c(8)-hsl-degrading activities were designated bpib01, bpib04, and bpib07. while the bpib07 protein was similar to a known lactonase, no sig ...200918997026
metagenome-derived clones encoding two novel lactonase family proteins involved in biofilm inhibition in pseudomonas aeruginosa.here we report the isolation and characterization of three metagenome-derived clones that interfere with bacterial quorum sensing and degrade n-(3-oxooctanoyl)-l-homoserine lactone (3-oxo-c(8)-hsl). by using a trai-lacz gene fusion, the metagenome-derived clones were identified from a soil dna library and analyzed. the open reading frames linked to the 3-oxo-c(8)-hsl-degrading activities were designated bpib01, bpib04, and bpib07. while the bpib07 protein was similar to a known lactonase, no sig ...200918997026
crystal structure of recx: a potent regulatory protein of reca from xanthomonas campestris. 200919003992
a new oxidative sensing and regulation pathway mediated by the mgra homologue sarz in staphylococcus aureus.oxidative stress serves as an important host/environmental signal that triggers a wide range of responses from the human pathogen staphylococcus aureus. among these, a thiol-based oxidation sensing pathway through a global regulator mgra controls the virulence and antibiotic resistance of the bacterium. herein, we report a new thiol-based oxidation sensing and regulation system that is mediated through a parallel global regulator sarz. sarz is a functional homologue of mgra and is shown to affec ...200919007410
a new oxidative sensing and regulation pathway mediated by the mgra homologue sarz in staphylococcus aureus.oxidative stress serves as an important host/environmental signal that triggers a wide range of responses from the human pathogen staphylococcus aureus. among these, a thiol-based oxidation sensing pathway through a global regulator mgra controls the virulence and antibiotic resistance of the bacterium. herein, we report a new thiol-based oxidation sensing and regulation system that is mediated through a parallel global regulator sarz. sarz is a functional homologue of mgra and is shown to affec ...200919007410
xylella fastidiosa afimbrial adhesins mediate cell transmission to plants by leafhopper vectors.the interactions between the economically important plant-pathogenic bacterium xylella fastidiosa and its leafhopper vectors are poorly characterized. we used different approaches to determine how x. fastidiosa cells interact with the cuticular surface of the foreguts of vectors. we demonstrate that x. fastidiosa binds to different polysaccharides with various affinities and that these interactions are mediated by cell surface carbohydrate-binding proteins. in addition, competition assays showed ...200919011051
xylella fastidiosa afimbrial adhesins mediate cell transmission to plants by leafhopper vectors.the interactions between the economically important plant-pathogenic bacterium xylella fastidiosa and its leafhopper vectors are poorly characterized. we used different approaches to determine how x. fastidiosa cells interact with the cuticular surface of the foreguts of vectors. we demonstrate that x. fastidiosa binds to different polysaccharides with various affinities and that these interactions are mediated by cell surface carbohydrate-binding proteins. in addition, competition assays showed ...200919011051
a single plant resistance gene promoter engineered to recognize multiple tal effectors from disparate pathogens.plant pathogenic bacteria of the genus xanthomonas inject transcription-activator like (tal) effector proteins that manipulate the hosts' transcriptome to promote disease. however, in some cases plants take advantage of this mechanism to trigger defense responses. for example, transcription of the pepper bs3 and rice xa27 resistance (r) genes are specifically activated by the respective tal effectors avrbs3 from xanthomonas campestris pv. vesicatoria (xcv), and avrxa27 from x. oryzae pv. oryzae ...200919910532
induced er chaperones regulate a receptor-like kinase to mediate antiviral innate immune response in plants.mounting an effective innate immune response against pathogens requires the rapid and global reprogramming of host cellular processes. here we employed complementary proteomic methods to identify differentially regulated proteins early during a plant's defense response. besides defense-related proteins, constituents of the largest category of upregulated proteins were cytoplasmic- and er-residing molecular chaperones. investigating the significance of upregulated er chaperones, we find that sile ...200919917500
sober1 phospholipase activity suppresses phosphatidic acid accumulation and plant immunity in response to bacterial effector avrbst.arabidopsis thaliana ecotype pi-0 is resistant to pseudomonas syringae pathovar tomato (pst) strain dc3000 expressing the t3s effector protein avrbst. resistance is due to a loss of function mutation (sober1-1) in a conserved alpha/beta hydrolase, sober1 (suppressor of avrbst elicited resistance1). members of this superfamily possess phospholipase and carboxylesterase activity with diverse substrate specificity. the nature of sober1 enzymatic activity and substrate specificity was not known. sob ...200919918071
insertion of horizontally transferred genes within conserved syntenic regions of yeast genomes.horizontal gene transfer has been occasionally mentioned in eukaryotic genomes, but such events appear much less numerous than in prokaryotes, where they play important functional and evolutionary roles. in yeasts, few independent cases have been described, some of which corresponding to major metabolic functions, but no systematic screening of horizontally transferred genes has been attempted so far. taking advantage of the synteny conservation among five newly sequenced and annotated genomes o ...200919654869
the majority of the type iii effector inventory of pseudomonas syringae pv. tomato dc3000 can suppress plant immunity.the pseudomonas syringae type iii protein secretion system (t3ss) and the type iii effectors it injects into plant cells are required for plant pathogenicity and the ability to elicit a hypersensitive response (hr). the hr is a programmed cell death that is associated with effector-triggered immunity (eti). a primary function of p. syringae type iii effectors appears to be the suppression of eti and pathogen-associated molecular pattern-triggered immunity (pti), which is induced by conserved mol ...200919656042
systemic acquired resistance in soybean is regulated by two proteins, orthologous to arabidopsis npr1.systemic acquired resistance (sar) is induced in non-inoculated leaves following infection with certain pathogenic strains. sar is effective against many pathogens. salicylic acid (sa) is a signaling molecule of the sar pathway. the development of sar is associated with the induction of pathogenesis related (pr) genes. arabidopsis non-expressor of pr1 (npr1) is a regulatory gene of the sa signal pathway 123. sar in soybean was first reported following infection with colletotrichum trancatum that ...200919656407
mini-tn7 vectors as genetic tools for gene cloning at a single copy number in an industrially important and phytopathogenic bacteria, xanthomonas spp.transposon mini-tn7 vectors insert into the chromosome of several gram-negative bacteria in a site-specific manner. here, we showed the application of mini-tn7 as single copy site-specific integration vector system for xanthomonas campestris pv. campestris. the transposition of the mini-tn7 into the bacterial genome was detected at a tn7 attachment (atttn7) site located downstream of glms1. furthermore, using a newly constructed vector pbbr1flp2 containing the flipase (flp) recombinase for site- ...200919659730
comparative proteome analysis of xanthomonas campestris pv. campestris in the interaction with the susceptible and the resistant cultivars of brassica oleracea.black rot of cruciferous plants, caused by xanthomonas campestris pv. campestris, causes severe losses in agriculture around the world. this disease affects several cultures, including cabbage and broccoli, among others. proteome studies of this bacterium have been reported; however, most of them were performed using the bacterium grown under culture media conditions. recently, we have analyzed the proteome of x. campestris pv. campestris during the interaction with the susceptible cultivar of b ...200919663914
a "repertoire for repertoire" hypothesis: repertoires of type three effectors are candidate determinants of host specificity in xanthomonas.the genetic basis of host specificity for animal and plant pathogenic bacteria remains poorly understood. for plant pathogenic bacteria, host range is restricted to one or a few host plant species reflecting a tight adaptation to specific hosts.200919680562
comparative biology of two natural variants of the incq-2 family plasmids, pras3.1 and pras3.2.plasmids pras3.1 and pras3.2 are two closely related, natural variants of the incq-2 plasmid family that have identical plasmid backbones except for two differences. plasmid pras3.1 has five 6-bp repeat sequences in the promoter region of the mobb gene and four 22-bp iterons in its oriv region, whereas pras3.2 has only four 6-bp repeats and three 22-bp iterons. plasmid pras3.1 was found to have a higher copy number than pras3.2, and we show that the extra 6-bp repeat results in an increase in mo ...200919684126
discovery of a small molecule that blocks wall teichoic acid biosynthesis in staphylococcus aureus.both gram-positive and gram-negative bacteria contain bactoprenol-dependent biosynthetic pathways expressing non-essential cell surface polysaccharides that function as virulence factors. although these polymers are not required for bacterial viability in vitro, genes in many of the biosynthetic pathways are conditionally essential: they cannot be deleted except in strains incapable of initiating polymer synthesis. we report a cell-based, pathway-specific strategy to screen for small molecule in ...200919689117
the role of the conserved phenylalanine in the sigma54-interacting gaftga motif of bacterial enhancer binding proteins.sigma(54)-dependent transcription requires activation by bacterial enhancer binding proteins (bebps). bebps are members of the aaa+ (atpases associated with various cellular activities) protein family and typically form hexameric structures that are crucial for their atpase activity. the precise mechanism by which the energy derived from atp hydrolysis is coupled to biological output has several unknowns. here we use escherichia coli pspf, a model bebp involved in the transcription of stress res ...200919692583
methionine sulfoxide reductase b (msrb) of mycobacterium smegmatis plays a limited role in resisting oxidative stress.pathogenic mycobacteria including mycobacterium tuberculosis resists phagocyte generated reactive oxygen intermediates (roi) and this constitutes an important virulence mechanism. we have previously reported, using mycobacterium smegmatis as a model to identify the bacterial components that resist intracellular roi, that an antioxidant methionine sulfoxide reductase a (msra) plays a critical role in this process. in this study, we report the role of methionine sulfoxide reductase b (msrb) in res ...200920006300
the apo structure of sucrose hydrolase from xanthomonas campestris pv. campestris shows an open active-site groove.glycoside hydrolase family 13 (gh-13) mainly contains starch-degrading or starch-modifying enzymes. sucrose hydrolases utilize sucrose instead of amylose as the primary glucosyl donor. here, the catalytic properties and x-ray structure of sucrose hydrolase from xanthomonas campestris pv. campestris are reported. sucrose hydrolysis catalyzed by the enzyme follows michaelis-menten kinetics, with a k(m) of 60.7 mm and a k(cat) of 21.7 s(-1). the structure of the enzyme was solved at a resolution of ...200919966417
the complete genome sequence of xanthomonas albilineans provides new insights into the reductive genome evolution of the xylem-limited xanthomonadaceae.the xanthomonadaceae family contains two xylem-limited plant pathogenic bacterial species, xanthomonas albilineans and xylella fastidiosa. x. fastidiosa was the first completely sequenced plant pathogen. it is insect-vectored, has a reduced genome and does not possess hrp genes which encode a type iii secretion system found in most plant pathogenic bacteria. x. fastidiosa was excluded from the xanthomonas group based on phylogenetic analyses with rrna sequences.200920017926
bioefficacy of lantana camara l. against some human pathogens.antimicrobial efficacy of flavonoids (free and bound) and crude alkaloids of lantana camara l. was determined by disc diffusion assay against three bacteria (escherichia coli, proteus mirabilis, and staphylococcus aureus) and two fungi (candida albicans and trichophyton mentagrophytes). minimum inhibitory concentration, minimum bactericidal/fungicidal concentration and total activity were also studied. most susceptible microorganism in the present study was c. albicans followed by p. mirabilis, ...200920502587
stomata and pathogens: warfare at the gates.bacteria and fungi are capable of triggering stomatal closure through pathogen-associated molecular patterns (pamps), which prevents penetration through these pores. therefore, the stomata can be considered part of the plant innate immune response. some pathogens have evolved mechanisms to evade stomatal defense. the bacterial pathogen xanthomonas campestris pv. campestris (xcc), which infects plants of the brassicaceae family mainly through hydathodes, has also been reported to infect plants th ...200920514224
simple adhesive-tape-based sampling of tomato surfaces combined with rapid fluorescence in situ hybridization for salmonella detection.a simple adhesive-tape-based method for sampling of tomato surfaces was combined with fluorescence in situ hybridization for rapid culture-independent detection of salmonella strains. tapes could also be placed face-down on selective agar for on-tape enrichment of captured salmonella cells. overlay of cell-charged tapes with small volumes of liquid enrichment media enabled subsequent detection of tape-captured salmonella via flow cytometry.200919124588
xc1028 from xanthomonas campestris adopts a pilz domain-like structure without a c-di-gmp switch.the crystal structure of xc1028 from xanthomonas campestris has been determined to a resolution of 2.15 a using the multiple anomalous dispersion approach. it bears significant sequence identity and similarity values of 64.10% and 70.09%, respectively, with pa2960, a protein indispensable for type iv pilus-mediated twitching motility, after which the pilz motif was first named. however, both xc1028 and pa2960 lack detectable c-di-gmp binding capability. although xc1028 adopts a structure compris ...200919127589
oxidation of a single active site suffices for the functional inactivation of the dimeric bacillus subtilis ohrr repressor in vitro.bacillus subtilis ohrr is a dimeric repressor that senses organic peroxides and regulates the expression of the ohra peroxiredoxin. derepression results from oxidation of an active site cysteine which ultimately results in formation of a mixed disulfide with a low molecular weight thiol, a cyclic sulfenamide, or overoxidation to the sulfinic or sulfonic acids. we expressed a single-chain ohrr (scohrr) in which the two monomers were connected by a short amino-acid linker. scohrr variants containi ...200919129220
enhanced fructooligosaccharides and inulinase production by a xanthomonas campestris pv. phaseoli km 24 mutant.xanthomonas campestris pv phaseoli produced an extracellular endoinulinase (9.24 +/- 0.03 u ml(-1)) in an optimized medium comprising of 3% sucrose and 2.5% tryptone. x. campestris pv. phaseoli was further subjected to ethylmethanesulfonate mutagenesis and the resulting mutant, x. campestris pv. phaseoli km 24 demonstrated inulinase production of 22.09 +/- 0.03 u ml(-1) after 18 h, which was 2.4-fold higher than that of the wild type. inulinase production by this mutant was scaled up using sucro ...200919130092
a comparison between shaker and bioreactor performance based on the kinetic parameters of xanthan gum production.xanthan gum production was studied using sugarcane broth as the raw material and batch fermentation by xanthomonas campestris pv. campestris nrrl b-1459. the purpose of this study was to optimize the variables of sucrose, yeast extract, and ammonium nitrate concentrations and to determine the kinetic parameters of this bioreaction under optimized conditions. the effects of yeast extract and ammonium nitrate concentrations for a given sucrose concentration (12.1-37.8 g l(-1)) were evaluated by ce ...200919130306
flagellar biogenesis of xanthomonas campestris requires the alternative sigma factors rpon2 and flia and is temporally regulated by flha, flhb, and flgm.in prokaryotes, flagellar biogenesis is a complicated process involving over 40 genes. the phytopathogen xanthomonas campestris pv. campestris possesses a single polar flagellum, which is essential for the swimming motility. a sigma54 activator, fleq, has been shown to be required for the transcriptional activation of the flagellar type iii secretion system (f-t3ss), rod, and hook proteins. one of the two rpon genes, rpon2, encoding sigma54, is essential for flagellation. rpon2 and fleq direct t ...200919136588
imbalanced lignin biosynthesis promotes the sexual reproduction of homothallic oomycete pathogens.lignin is incorporated into plant cell walls to maintain plant architecture and to ensure long-distance water transport. lignin composition affects the industrial value of plant material for forage, wood and paper production, and biofuel technologies. industrial demands have resulted in an increase in the use of genetic engineering to modify lignified plant cell wall composition. however, the interaction of the resulting plants with the environment must be analyzed carefully to ensure that there ...200919148278
the safety of polyglycoplex (pgx) as shown in a 90-day rodent feeding study.this study was designed to evaluate the safety of polyglycoplex (pgx), a novel viscous dietary polysaccharide (fiber), when administered to sprague dawley(r) rats in the diet for 90 days.200919149876
chromosome-based genetic complementation system for xylella fastidiosa.xylella fastidiosa is a xylem-limited, gram-negative bacterium that causes pierce's disease of grapevine. here, we describe the construction of four vectors that facilitate the insertion of genes into a neutral site (ns1) in the x. fastidiosa chromosome. these vectors carry a cole1-like (pmb1) replicon and dna sequences from ns1 flanking a multiple-cloning site and a resistance marker for one of the following antibiotics: chloramphenicol, erythromycin, gentamicin, or kanamycin. in x. fastidiosa, ...200919151176
environmental control in tea fields to reduce infection by pseudomonas syringae pv. theae.bacterial shoot blight (bsb) disease, caused by pseudomonas syringae pv. theae, is a major bacterial disease of tea plants in japan. bsb mainly occurs in the low-temperature season, and lesion formation by p. syringae pv. theae is enhanced by both low temperature and the presence of ice nucleation-active xanthomonas campestris (inax), which catalyzes ice formation at -2 to -4 degrees c and is frequently co-isolated with p. syringae pv. theae from tea plants. low temperature is thus the most impo ...200919159313
rodz, a component of the bacterial core morphogenic apparatus.the molecular basis of bacterial cell morphogenesis remains largely an open question. here we discover a morphogenic protein, rodz, which is widely conserved across the bacterial kingdom. in caulobacter crescentus, rodz is essential for viability and is involved in all aspects of this organism's complex morphology. depletion or over-production of rodz results in grossly misshapen cells with stalk defects. rodz exhibits a localization pattern during the cell cycle corresponding to sites of active ...200919164570
an approach to characterizing single-subunit mutations in multimeric prepores and pores of anthrax protective antigen.heptameric pores formed by the protective antigen (pa) moiety of anthrax toxin translocate the intracellular effector moieties of the toxin across the endosomal membrane to the cytosol of mammalian cells. we devised a protocol to characterize the effects of individual mutations in a single subunit of heptameric pa prepores (pore precursors) or pores. we prepared monomeric pa containing a test mutation plus an innocuous cys-replacement mutation at a second residue (lys563, located on the external ...200919165720
the tep1 gene of sinorhizobium meliloti coding for a putative transmembrane efflux protein and n-acetyl glucosamine affect nod gene expression and nodulation of alfalfa plants.soil bacteria collectively known as rhizobium, characterized by their ability to establish beneficial symbiosis with legumes, share several common characteristics with pathogenic bacteria when infecting the host plant. recently, it was demonstrated that a fadd mutant of sinorhizobium meliloti is altered in the control of swarming, a type of co-ordinated movement previously associated with pathogenicity, and is also impaired in nodulation efficiency on alfalfa roots. in the phytopathogen xanthomo ...200919173735
genome sequence of desulfobacterium autotrophicum hrm2, a marine sulfate reducer oxidizing organic carbon completely to carbon dioxide.sulfate-reducing bacteria (srb) belonging to the metabolically versatile desulfobacteriaceae are abundant in marine sediments and contribute to the global carbon cycle by complete oxidation of organic compounds. desulfobacterium autotrophicum hrm2 is the first member of this ecophysiologically important group with a now available genome sequence. with 5.6 megabasepairs (mbp) the genome of db. autotrophicum hrm2 is about 2 mbp larger than the sequenced genomes of other sulfate reducers (srb). a h ...200919187283
a filamentous hemagglutinin-like protein of xanthomonas axonopodis pv. citri, the phytopathogen responsible for citrus canker, is involved in bacterial virulence.xanthomonas axonopodis pv. citri, the phytopathogen responsible for citrus canker has a number of protein secretion systems and among them, at least one type v protein secretion system belonging to the two-partner secretion pathway. this system is mainly associated to the translocation of large proteins such as adhesins to the outer membrane of several pathogens. xanthomonas axonopodis pv. citri possess a filamentous hemagglutinin-like protein in close vicinity to its putative transporter protei ...200919194503
phylogenetic structure of xanthomonas determined by comparison of gyrb sequences.previously, we have produced a phylogeny of species type strains from the plant-pathogenic genus xanthomonas based on gyrb sequences. to evaluate this locus further for species and infraspecies identification, we sequenced an additional 203 strains comprising all the pathovar reference strains (which have defined plant hosts), 67 poorly characterized pathovars, currently classified as xanthomonas campestris, and 59 unidentified xanthomonads. the well-characterized pathovars grouped either in cla ...200919196764
unique gtp-binding pocket and allostery of uridylate kinase from a gram-negative phytopathogenic bacterium.using x-ray diffraction methodology, we have successfully determined the tertiary structures of the apo- and gtp-bound forms of uridylate kinase (umpk) from the gram-negative plant pathogen xanthomonas campestris with crystals grown under a strong magnetic field. the flexible atp- and ump-binding loops are clearly shown under this situation. x. campestris umpk contains a unique patch of noticeably positive nature from residue r100 to residue r127, allowing it to form a special gtp-binding pocket ...200919059268
y4lo of rhizobium sp. strain ngr234 is a symbiotic determinant required for symbiosome differentiation.type 3 (t3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial t3 secretion system, affect the nodulation of certain host legumes. the open reading frame y4lo of rhizobium sp. strain ngr234 encodes a protein with sequence similarities to t3 effectors from pathogenic bacteria (the yopj effector family). transcription studies showed that the promoter activity of y4lo depended on the transcriptional activator ttsi. recombinant y4lo protein expressed in escherichia coli did not ...200919060155
y4lo of rhizobium sp. strain ngr234 is a symbiotic determinant required for symbiosome differentiation.type 3 (t3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial t3 secretion system, affect the nodulation of certain host legumes. the open reading frame y4lo of rhizobium sp. strain ngr234 encodes a protein with sequence similarities to t3 effectors from pathogenic bacteria (the yopj effector family). transcription studies showed that the promoter activity of y4lo depended on the transcriptional activator ttsi. recombinant y4lo protein expressed in escherichia coli did not ...200919060155
the role of ampr in regulation of l1 and l2 beta-lactamases in stenotrophomonas maltophilia.stenotrophomonas maltophilia is known to produce at least two chromosomal-mediated inducible beta-lactamases, l1 and l2. gene l2, which encodes a class a beta-lactamase, and the adjacent ampr gene form an ampr-class a beta-lactamase module. l1 belongs to the class b beta-lactamase and has no neighbor ampr-like regulatory gene. in this study, the ampr-l2 module from s. maltophilia kh was compared with ampr-beta-lactamase modules from several microorganisms with respect to the ampr and beta-lactam ...200919071216
regulation and activity of a zinc uptake regulator, zur, in corynebacterium diphtheriae.regulation of metal ion homeostasis is essential to bacterial cell survival, and in most species it is controlled by metal-dependent transcriptional regulators. in this study, we describe a corynebacterium diphtheriae ferric uptake regulator-family protein, zur, that controls expression of genes involved in zinc uptake. by measuring promoter activities and mrna levels, we demonstrate that zur represses transcription of three genes (zrg, cmra, and troa) in zinc-replete conditions. all three of th ...200919074382
regulation and activity of a zinc uptake regulator, zur, in corynebacterium diphtheriae.regulation of metal ion homeostasis is essential to bacterial cell survival, and in most species it is controlled by metal-dependent transcriptional regulators. in this study, we describe a corynebacterium diphtheriae ferric uptake regulator-family protein, zur, that controls expression of genes involved in zinc uptake. by measuring promoter activities and mrna levels, we demonstrate that zur represses transcription of three genes (zrg, cmra, and troa) in zinc-replete conditions. all three of th ...200919074382
a fatty acid messenger is responsible for inducing dispersion in microbial biofilms.it is well established that in nature, bacteria are found primarily as residents of surface-associated communities called biofilms. these structures form in a sequential process initiated by attachment of cells to a surface, followed by the formation of matrix-enmeshed microcolonies, and culminating in dispersion of the bacteria from the mature biofilm. in the present study, we have demonstrated that, during growth, pseudomonas aeruginosa produces an organic compound we have identified as cis-2- ...200919074399
a fatty acid messenger is responsible for inducing dispersion in microbial biofilms.it is well established that in nature, bacteria are found primarily as residents of surface-associated communities called biofilms. these structures form in a sequential process initiated by attachment of cells to a surface, followed by the formation of matrix-enmeshed microcolonies, and culminating in dispersion of the bacteria from the mature biofilm. in the present study, we have demonstrated that, during growth, pseudomonas aeruginosa produces an organic compound we have identified as cis-2- ...200919074399
an orphan luxr homolog of sinorhizobium meliloti affects stress adaptation and competition for nodulation.the sin/expr quorum-sensing system of sinorhizobium meliloti plays an important role in the symbiotic association with its host plant, medicago sativa. the luxr-type response regulators of the sin system include the synthase (sini)-associated sinr and the orphan regulator expr. interestingly, the s. meliloti rm1021 genome codes for four additional putative orphan luxr homologs whose regulatory roles remain to be identified. these response regulators contain the characteristic domains of the luxr ...200919088317
an orphan luxr homolog of sinorhizobium meliloti affects stress adaptation and competition for nodulation.the sin/expr quorum-sensing system of sinorhizobium meliloti plays an important role in the symbiotic association with its host plant, medicago sativa. the luxr-type response regulators of the sin system include the synthase (sini)-associated sinr and the orphan regulator expr. interestingly, the s. meliloti rm1021 genome codes for four additional putative orphan luxr homologs whose regulatory roles remain to be identified. these response regulators contain the characteristic domains of the luxr ...200919088317
overexpression of lipid transfer protein (ltp) genes enhances resistance to plant pathogens and ltp functions in long-distance systemic signaling in tobacco.the lipid signal is essential for the activation of plant defense responses, but downstream components of the signaling pathway are still poorly defined. to investigate the biological functions of pepper lipid transfer protein (ltp), we carried out virus-induced gene silencing (vigs) in pepper, constitutive expression of caltps and grafting experiments in the tobacco plant. suppression of endogenous caltpi and caltpii by vigs, respectively, resulted in enhanced susceptibility to xanthomonas camp ...200919089429
xanthomonas campestris overcomes arabidopsis stomatal innate immunity through a dsf cell-to-cell signal-regulated virulence factor.pathogen-induced stomatal closure is part of the plant innate immune response. phytopathogens using stomata as a way of entry into the leaf must avoid the stomatal response of the host. in this article, we describe a factor secreted by the bacterial phytopathogen xanthomonas campestris pv campestris (xcc) capable of interfering with stomatal closure induced by bacteria or abscisic acid (aba). we found that living xcc, as well as ethyl acetate extracts from xcc culture supernatants, are capable o ...200919091877
heme-dependent metalloregulation by the iron response regulator (irr) protein in rhizobium and other alpha-proteobacteria.perception and response to nutritional iron by bacteria is essential for viability, and for the ability to adapt to the environment. the iron response regulator (irr) is part of a novel regulatory scheme employed by rhizobium and other alpha-proteobacteria to control iron-dependent gene expression. bradyrhizobium japonicum senses iron through the status of heme biosynthesis to regulate gene expression, thus it responds to an iron-dependent process rather than to iron directly. irr mediates this ...200919093075
heme-dependent metalloregulation by the iron response regulator (irr) protein in rhizobium and other alpha-proteobacteria.perception and response to nutritional iron by bacteria is essential for viability, and for the ability to adapt to the environment. the iron response regulator (irr) is part of a novel regulatory scheme employed by rhizobium and other alpha-proteobacteria to control iron-dependent gene expression. bradyrhizobium japonicum senses iron through the status of heme biosynthesis to regulate gene expression, thus it responds to an iron-dependent process rather than to iron directly. irr mediates this ...200919093075
mechanism of allosteric inhibition of n-acetyl-l-glutamate synthase by l-arginine.n-acetylglutamate synthase (nags) catalyzes the first committed step in l-arginine biosynthesis in plants and micro-organisms and is subject to feedback inhibition by l-arginine. this study compares the crystal structures of nags from neisseria gonorrhoeae (ngnags) in the inactive t-state with l-arginine bound and in the active r-state complexed with coa and l-glutamate. under all of the conditions examined, the enzyme consists of two stacked trimers. each monomer has two domains: an amino acid ...200919095660
substrate-protein interaction in human tryptophan dioxygenase: the critical role of h76.the initial and rate-limiting step of the kynurenine pathway in humans involves the oxidation of tryptophan to n-formyl kynurenine catalyzed by two hemeproteins, tryptophan 2,3-dioxygenase (htdo) and indoleamine 2,3-dioxygenase (hido). in htdo, the conserved h76 residue is believed to act as an active site base to deprotonate the indole nh group of trp, the initial step of the trp oxidation reaction. in hido, this histidine is replaced by a serine. to investigate the role of the h76, we have stu ...200919209904
functional expression of a bacterial xylose isomerase in saccharomyces cerevisiae.in industrial fermentation processes, the yeast saccharomyces cerevisiae is commonly used for ethanol production. however, it lacks the ability to ferment pentose sugars like d-xylose and l-arabinose. heterologous expression of a xylose isomerase (xi) would enable yeast cells to metabolize xylose. however, many attempts to express a prokaryotic xi with high activity in s. cerevisiae have failed so far. we have screened nucleic acid databases for sequences encoding putative xis and finally were a ...200919218403
characterization of regulatory pathways in xylella fastidiosa: genes and phenotypes controlled by gaca.the xylem-limited, insect-transmitted bacterium xylella fastidiosa causes pierce's disease in grapes through cell aggregation and vascular clogging. gaca controls various physiological processes and pathogenicity factors in many gram-negative bacteria, including biofilm formation in pseudomonas syringae pv. tomato dc3000. cloned gaca of x. fastidiosa was found to restore the hypersensitive response and pathogenicity in gaca mutants of p. syringae pv. tomato dc3000 and erwinia amylovora. a gaca m ...200919218414
co-regulation of xanthomonas campestris virulence by quorum sensing and a novel two-component regulatory system ravs/ravr.xanthomonas campestris pv. campestris (xcc) is known to regulate virulence through a quorum-sensing mechanism. detection of the quorum-sensing signal dsf by sensor rpfc leads to activation of the response regulator rpfg, which influences virulence by degrading cyclic-di-gmp and by subsequent increasing expression of the global regulator clp. in this study, we show that mutation of a response regulator ravr containing the ggdef-eal domains decreases xcc virulence factor production. the functional ...200919220743
export of functional streptomyces coelicolor alditol oxidase to the periplasm or cell surface of escherichia coli and its application in whole-cell biocatalysis.streptomyces coelicolor a3(2) alditol oxidase (aldo) is a soluble monomeric flavoprotein in which the flavin cofactor is covalently linked to the polypeptide chain. aldo displays high reactivity towards different polyols such as xylitol and sorbitol. these characteristics make aldo industrially relevant, but full biotechnological exploitation of this enzyme is at present restricted by laborious and costly purification steps. to eliminate the need for enzyme purification, this study describes a w ...200919224207
visualization of novel virulence activities of the xanthomonas type iii effectors avrbs1, avrbs3 and avrbs4.xanthomonas campestris pv. vesicatoria secretes at least 20 effector proteins through the type iii secretion system directly into plant cells. in this study, we uncovered virulence activities of the effector proteins avrbs1, avrbs3 and avrbs4 using agrobacterium-mediated transient expression of the corresponding genes in nicotiana benthamiana, followed by microscopic analyses. we showed that, in addition to the nuclear-localized avrbs3, the effector avrbs1, which localizes to the plant cell cyto ...200919236567
structure and function of pseudomonas aeruginosa protein pa1324 (21-170).pseudomonas aeruginosa is the prototypical biofilm-forming gram-negative opportunistic human pathogen. p. aeruginosa is causatively associated with nosocomial infections and with cystic fibrosis. antibiotic resistance in some strains adds to the inherent difficulties that result from biofilm formation when treating p. aeruginosa infections. transcriptional profiling studies suggest widespread changes in the proteome during quorum sensing and biofilm development. many of the proteins found to be ...200919241370
low molecular weight plant extract induces metabolic changes and the secretion of extracellular enzymes, but has a negative effect on the expression of the type-iii secretion system in xanthomonas campestris pv. campestris.xanthomonas campestris pathovar campestris (xcc) is a plant pathogenic bacterium and as such has to adapt to a variety of environments. during the course of disease, xcc colonizes the surface of its host, infects the xylem in the early stages, and develops a fully saprophytic life-style, aided by secreted degradative enzymes, in the late stages. to get some insight into this complex regulation, xcc was cultivated in the presence of low molecular weight host plant extract (<10 kda). from this exp ...200919114064
functional characterization of the type iii secretion atpase hrcn from the plant pathogen xanthomonas campestris pv. vesicatoria.many gram-negative plant and animal pathogenic bacteria employ a type iii secretion (t3s) system to inject effector proteins into the cytosol of eukaryotic host cells. the membrane-spanning t3s apparatus is associated with an atpase that presumably provides the energy for the secretion process. here, we describe the role of the predicted atpase hrcn from the plant pathogenic bacterium xanthomonas campestris pathovar vesicatoria. we show that hrcn hydrolyzes atp in vitro and is essential for t3s ...200919114489
functional characterization of the type iii secretion atpase hrcn from the plant pathogen xanthomonas campestris pv. vesicatoria.many gram-negative plant and animal pathogenic bacteria employ a type iii secretion (t3s) system to inject effector proteins into the cytosol of eukaryotic host cells. the membrane-spanning t3s apparatus is associated with an atpase that presumably provides the energy for the secretion process. here, we describe the role of the predicted atpase hrcn from the plant pathogenic bacterium xanthomonas campestris pathovar vesicatoria. we show that hrcn hydrolyzes atp in vitro and is essential for t3s ...200919114489
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