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a suppressor of the menadione-hypersensitive phenotype of a xanthomonas campestris pv. phaseoli oxyr mutant reveals a novel mechanism of toxicity and the protective role of alkyl hydroperoxide reductase.we isolated menadione-resistant mutants of xanthomonas campestris pv. phaseoli oxyr (oxyr(xp)). the oxyrr2(xp) mutant was hyperresistant to the superoxide generators menadione and plumbagin and was moderately resistant to h(2)o(2) and tert-butyl hydroperoxide. analysis of enzymes involved in oxidative-stress protection in the oxyrr2(xp) mutant revealed a >10-fold increase in ahpc and ahpf levels, while the levels of superoxide dismutase (sod), catalase, and the organic hydroperoxide resistance p ...200312591894
type ii protein secretion in pseudomonas aeruginosa: the pseudopilus is a multifibrillar and adhesive structure.the type ii secretion pathway of pseudomonas aeruginosa is involved in the extracellular release of various toxins and hydrolytic enzymes such as exotoxin a and elastase. this pathway requires the function of a macromolecular complex called the xcp secreton. the xcp secreton shares many features with the machinery involved in type iv pilus assembly. more specifically, it involves the function of five pilin-like proteins, the xcpt-x pseudopilins. we show that, upon overexpression, the xcpt pseudo ...200312700254
isolation and antifungal and antioomycete activities of aerugine produced by pseudomonas fluorescens strain mm-b16.the bacterial strain mm-b16, which showed strong antifungal and antioomycete activity against some plant pathogens, was isolated from a mountain forest soil in korea. based on the physiological and biochemical characteristics and 16s ribosomal dna sequence analysis, the bacterial strain mm-b16 was identical to pseudomonas fluorescens. an antibiotic active against colletotrichum orbiculare and phytophthora capsici in vitro and in vivo was isolated from the culture filtrates of p. fluorescens stra ...200312676678
characterization of the xanthomonas axonopodis pv. glycines hrp pathogenicity island.we sequenced an approximately 29-kb region from xanthomonas axonopodis pv. glycines that contained the hrp type iii secretion system, and we characterized the genes in this region by tn3-gus mutagenesis and gene expression analyses. from the region, hrp (hypersensitive response and pathogenicity) and hrc (hrp and conserved) genes, which encode type iii secretion systems, and hpa (hrp-associated) genes were identified. the characteristics of the region, such as the presence of many virulence gene ...200312730176
hlm1, an essential signaling component in the hypersensitive response, is a member of the cyclic nucleotide-gated channel ion channel family.the hypersensitive response (hr) in plants is a programmed cell death that is commonly associated with disease resistance. a novel mutation in arabidopsis, hlm1, which causes aberrant regulation of cell death, manifested by a lesion-mimic phenotype and an altered hr, segregated as a single recessive allele. broad-spectrum defense mechanisms remained functional or were constitutive in the mutant plants, which also exhibited increased resistance to a virulent strain of pseudomonas syringae pv toma ...200312566578
ethylene insensitivity modulates ozone-induced cell death in birch.we have used genotypic variation in birch (betula pendula roth) to investigate the roles of ozone (o(3))-induced ethylene (et), jasmonic acid, and salicylic acid in the regulation of tissue tolerance to o(3). of these hormones, et evolution correlated best with o(3)-induced cell death. disruption of et perception by transformation of birch with the dominant negative mutant allele etr1-1 of the arabidopsis et receptor gene etr1 or blocking of et perception with 1-methylcyclopropene reduced but di ...200312746524
differential effects of elevated ozone on two hybrid aspen genotypes predisposed to chronic ozone fumigation. role of ethylene and salicylic acid.the role of ethylene (et) signaling in the responses of two hybrid aspen (populus tremula l. x p. tremuloides michx.) clones to chronic ozone (o(3); 75 nl l(-1)) was investigated. the hormonal responses differed between the clones; the o(3)-sensitive clone 51 had higher et evolution than the tolerant clone 200 during the exposure, whereas the free salicylic acid concentration in clone 200 was higher than in clone 51. the cellular redox status, measured as glutathione redox balance, did not diffe ...200312746525
expression of putative pathogenicity-related genes in xylella fastidiosa grown at low and high cell density conditions in vitro.xylella fastidiosa is the causal agent of economically important plant diseases, including citrus variegated chlorosis and pierce's disease. hitherto, there has been no information on the molecular mechanisms controlling x. fastidiosa-plant interactions. to determine whether predicted open reading frames (orfs) encoding putative pathogenicity-related factors were expressed by x. fastidiosa 9a5c cells grown at low (lcd) and high cell density (hcd) conditions in liquid modified pw medium, reverse ...200312757950
intracellular peptidoglycan hydrolases of the bacterium xanthomonas campestris xl-1.a system of intracellular peptidoglycan hydrolases of xanthomonas campestris xl-1 comprises about 10 enzymes of different localization and substrate specificity. seven enzymes (a(1)-a(7)) are localized in cytosol, one enzyme (a(8)) in periplasm, and two enzymes (a(9), a(10)) were found in the fraction of cell walls and membranes. while the culture is entering the logarithmic growth stage from the stationary stage, a change occurs in the activity of the cytosolic enzymes: a(1) significantly incre ...200312765529
small ubiquitin-like modifier modulates abscisic acid signaling in arabidopsis.post-translational modification of proteins by small polypeptides, such as ubiquitin, has emerged as a common and important mechanism for regulating protein function. small ubiquitin-like modifier (sumo) is a small protein that is structurally related to but functionally different from ubiquitin. we report the identification and functional analysis of atsumo1, atsumo2, and atsce1a as components of the sumo conjugation (sumoylation) pathway in arabidopsis. in yeast-two hybrid assays, atsumo1/2 in ...200312782728
consensus-degenerate hybrid oligonucleotide primers for amplification of priming glycosyltransferase genes of the exopolysaccharide locus in strains of the lactobacillus casei group.a primer design strategy named codehop (consensus-degenerate hybrid oligonucleotide primer) for amplification of distantly related sequences was used to detect the priming glycosyltransferase (gt) gene in strains of the lactobacillus casei group. each hybrid primer consisted of a short 3' degenerate core based on four highly conserved amino acids and a longer 5' consensus clamp region based on six sequences of the priming gt gene products from exopolysaccharide (eps)-producing bacteria. the hybr ...200312788729
nutritional similarity between leaf-associated nonpathogenic bacteria and the pathogen is not predictive of efficacy in biological control of bacterial spot of tomato.it has been demonstrated that for a nonpathogenic, leaf-associated bacterium, effectiveness in the control of bacterial speck of tomato is correlated with the similarity in the nutritional needs of the nonpathogenic bacterium and the pathogen pseudomonas syringae pv. tomato. this relationship was investigated further in this study by using the pathogen xanthomonas campestris pv. vesicatoria, the causal agent of bacterial spot of tomato, and a collection of nonpathogenic bacteria isolated from to ...200312788754
physical interaction between rrs1-r, a protein conferring resistance to bacterial wilt, and popp2, a type iii effector targeted to the plant nucleus.rrs1-r confers broad-spectrum resistance to several strains of the causal agent of bacterial wilt, ralstonia solanacearum. although genetically defined as recessive, this r gene encodes a protein whose structure combines the tir-nbs-lrr domains found in several r proteins and a wrky motif characteristic of some plant transcriptional factors and behaves as a dominant gene in transgenic susceptible plants. here we show that popp2, a r. solanacearum type iii effector, which belongs to the yopj/avrr ...200312788974
development of a phenomenological modeling approach for prediction of growth and xanthan gum production using xanthomonas campestris.an unstructured kinetic model for xanthan production is described and fitted to experimental data obtained in a stirred batch reactor. the culture medium was composed of several nitrogen sources (soybean hydrolysates, ammonium and nitrate salts) consumed sequentially. the model proposed is able to describe this sequential consumption of nitrogen sources, the consumption of inorganic phosphate and carbon, the evolution of biomass, and production of xanthan. the parameter estimation has been perfo ...200312790645
expression of peroxidase-like genes, h2o2 production, and peroxidase activity during the hypersensitive response to xanthomonas campestris pv. vesicatoria in capsicum annuum.pepper ascorbate peroxidase-like (capoa1), thioredoxin peroxidase-like (capot1), and peroxidase-like (capo1) clones were isolated from pepper leaves inoculated with avirulent strain bv5-4a of xanthomonas campestris pv. vesicatoria. capoa1, capot1, and capo1 mrna disappeared 18 to 30 h after the bacterial infection when the hypersensitive response (hr) was visible. in contrast, peroxidase activity reached a peak at 18 h after infection and then declined at 24 and 30 h when h2o2 accumulation level ...200312650451
the mosaic structure of the symbiotic plasmid of rhizobium etli cfn42 and its relation to other symbiotic genome compartments.symbiotic bacteria known as rhizobia interact with the roots of legumes and induce the formation of nitrogen-fixing nodules. in rhizobia, essential genes for symbiosis are compartmentalized either in symbiotic plasmids or in chromosomal symbiotic islands. to understand the structure and evolution of the symbiotic genome compartments (sgcs), it is necessary to analyze their common genetic content and organization as well as to study their differences. to date, five sgcs belonging to distinct spec ...200312801410
survivability and long-term preservation of bacteria in water and in phosphate-buffered saline.to evaluate the suitability of using sterile water and phosphate-buffered saline (pbs) for preservation of bacteria pathogenic to plants or humans.200312803555
three pathogen-inducible genes encoding lipid transfer protein from pepper are differentially activated by pathogens, abiotic, and environmental stresses.the three cdna clones, caltpi, caltpii, and caltpiii, corresponding to pepper lipid transfer protein (ltp) genes were isolated from a pepper (capsicum annuum) cdna library from hypersensitive response (hr) lesions of leaves infected with xanthomonas campestris pv. vesicatoria. the caltp genes are well conserved in their coding region with 57-72% identity at the amino acid level, but display 72-83% identity at the nucleotide sequence level. the transcripts of the three caltp genes differentially ...200312803619
arabidopsis contains a large superfamily of acyl-activating enzymes. phylogenetic and biochemical analysis reveals a new class of acyl-coenzyme a synthetases.acyl-activating enzymes are a diverse group of proteins that catalyze the activation of many different carboxylic acids, primarily through the formation of a thioester bond. this group of enzymes is found in all living organisms and includes the acyl-coenzyme a synthetases, 4-coumarate:coenzyme a ligases, luciferases, and non-ribosomal peptide synthetases. the members of this superfamily share little overall sequence identity, but do contain a 12-amino acid motif common to all enzymes that activ ...200312805634
a pseudomonas syringae type iii effector suppresses cell wall-based extracellular defense in susceptible arabidopsis plants.bacterial effector proteins secreted through the type iii secretion system (ttss) play a crucial role in causing plant and human diseases. although the ability of type iii effectors to trigger defense responses in resistant plants is well understood, the disease-promoting functions of type iii effectors in susceptible plants are largely enigmatic. previous microscopic studies suggest that in susceptible plants the ttss of plant-pathogenic bacteria transports suppressors of a cell wall-based plan ...200312817082
crystal structure of a putative methyltransferase from mycobacterium tuberculosis: misannotation of a genome clarified by protein structural analysis.bioinformatic analyses of whole genome sequences highlight the problem of identifying the biochemical and cellular functions of many gene products that are at present uncharacterized. the open reading frame rv3853 from mycobacterium tuberculosis has been annotated as meng and assumed to encode an s-adenosylmethionine (sam)-dependent methyltransferase that catalyzes the final step in menaquinone biosynthesis. the rv3853 gene product has been expressed, refolded, purified, and crystallized in the ...200312837779
detection and diversity assessment of xylella fastidiosa in field-collected plant and insect samples by using 16s rrna and gyrb sequences.the causal agent of diseases in many economically important plants is attributed to the xylem-limited bacterium xylella fastidiosa. the detection of this plant pathogen has been hampered due to its difficult isolation and slow growth on plates. nearly complete nucleotide sequences of the 16s rrna gene and partial sequences of the gyrb gene were determined for 18 strains of x. fastidiosa isolated from different plant hosts. a phylogenetic analysis, based on gyrb, grouped strains in three clusters ...200312839807
sm-like proteins in eubacteria: the crystal structure of the hfq protein from escherichia coli.the hfq protein was discovered in escherichia coli in the early seventies as a host factor for the qbeta phage rna replication. during the last decade, it was shown to be involved in many rna processing events and remote sequence homology indicated a link to spliceosomal sm proteins. we report the crystal structure of the e.coli hfq protein showing that its monomer displays a characteristic sm-fold and forms a homo-hexamer, in agreement with former biochemical data. overall, the structure of the ...200312853626
simultaneous analysis of phytohormones, phytotoxins, and volatile organic compounds in plants.phytohormones regulate the protective responses of plants against both biotic and abiotic stresses by means of synergistic or antagonistic actions referred to as signaling crosstalk. a bottleneck in crosstalk research is the quantification of numerous interacting phytohormones and regulators. the chemical analysis of salicylic acid, jasmonic acid, indole-3-acetic acid, and abscisic acid is typically achieved by using separate and complex methodologies. moreover, pathogen-produced phytohormone mi ...200312874387
productivity improvement in xanthan gum fermentation using multiple substrate optimization.a novel and more comprehensive formulation of the optimal control problem that reflects the operational requirements of a typical industrial fermentation has been proposed in this work. this formulation has been applied to a fed-batch bioreactor with three control variables, i.e., feed rates of carbon source, nitrogen source, and an oxygen source, to result in a 148.7% increase in product formation. xanthan gum production using xanthomonas campestris has been used as the model system for this op ...200312892481
quorum sensing in plant-pathogenic bacteria.quorum sensing (qs) allows bacteria to assess their local population density and/or physical confinement via the secretion and detection of small, diffusible signal molecules. this review describes how phytopathogenic bacteria have incorporated qs mechanisms into complex regulatory cascades that control genes for pathogenicity and colonization of host surfaces. traits regulated by qs include the production of extracellular polysaccharides, degradative enzymes, antibiotics, siderophores, and pigm ...200312730390
[the bactericidal activity of lectins from nitrogen-fixing bacilli].lectins i and ii isolated from the nitrogen-fixing soil bacterium paenibacillus polymyxa 1460 were found to be able to suppress the growth of rhizobium leguminosarum 252 and bacillus subtilis 36 at nearly all the concentrations tested (from 1 to 10 micrograms/ml). lectin i was also inhibitory to azospirillum brasilense 245 and erwinia carotovora subsp. citrulis 603, while lectin ii exerted bactericidal activity against xanthomonas campestris b-610 and b-611 and a. brasilense 245. the bacillar le ...200312901008
asexual development is increased in neurospora crassa cat-3-null mutant strains.we use asexual development of neurospora crassa as a model system with which to determine the causes of cell differentiation. air exposure of a mycelial mat induces hyphal adhesion, and adherent hyphae grow aerial hyphae that, in turn, form conidia. previous work indicated the development of a hyperoxidant state at the start of these morphogenetic transitions and a large increase in catalase activity during conidiation. catalase 3 (cat-3) increases at the end of exponential growth and is induced ...200312912899
overexpression of the disease resistance gene pto in tomato induces gene expression changes similar to immune responses in human and fruitfly.the pto gene encodes a serine/threonine protein kinase that confers resistance in tomato (lycopersicon esculentum) to pseudomonas syringae pv tomato strains that express the type iii effector protein avrpto. constitutive overexpression of pto in tomato, in the absence of avrpto, activates defense responses and confers resistance to several diverse bacterial and fungal plant pathogens. we have used a series of gene discovery and expression profiling methods to examine the effect of pto overexpres ...200312913147
prophage genomics.the majority of the bacterial genome sequences deposited in the national center for biotechnology information database contain prophage sequences. analysis of the prophages suggested that after being integrated into bacterial genomes, they undergo a complex decay process consisting of inactivating point mutations, genome rearrangements, modular exchanges, invasion by further mobile dna elements, and massive dna deletion. we review the technical difficulties in defining such altered prophage sequ ...200312794192
honor thy symbionts.our intestine is the site of an extraordinarily complex and dynamic environmentally transmitted consortial symbiosis. the molecular foundations of beneficial symbiotic host-bacterial relationships in the gut are being revealed in part from studies of simplified models of this ecosystem, where germ-free mice are colonized with specified members of the microbial community, and in part from comparisons of the genomes of members of the intestinal microbiota. the results emphasize the contributions o ...200312923294
the complete genome sequence of the arabidopsis and tomato pathogen pseudomonas syringae pv. tomato dc3000.we report the complete genome sequence of the model bacterial pathogen pseudomonas syringae pathovar tomato dc3000 (dc3000), which is pathogenic on tomato and arabidopsis thaliana. the dc3000 genome (6.5 megabases) contains a circular chromosome and two plasmids, which collectively encode 5,763 orfs. we identified 298 established and putative virulence genes, including several clusters of genes encoding 31 confirmed and 19 predicted type iii secretion system effector proteins. many of the virule ...200312928499
direct delivery of bacterial avirulence proteins into resistant arabidopsis protoplasts leads to hypersensitive cell death.many bacterial avirulence (avr) proteins, including the pseudomonas syringae proteins, avrrpt2 and avrb, appear to be recognized inside the host plant cell by resistance mechanisms mediated by the cognate resistance (r) genes. it is thought that avr proteins are either delivered directly into the host cell via the bacterial type iii secretion system (ttss) or taken up by the plant cell following secretion into the apoplast through the ttss. recently, it was shown that the xanthomonas campestris ...200312943547
efficient synthesis of a heptasaccharide, the repeating unit of the o-chain lipopolysaccharide produced by xanthomonas campestris strain 642.alpha-l-rhap-(1-->3)-alpha-l-rhap-(1-->2)-alpha-l-rhap-(1-->3)-[beta-d-xylp-(1-->2)-][beta-d-xylp-(1-->4)-]alpha-l-rhap-(1-->3)-alpha-l-rhap, the repeating unit of the o-chain lipopolysaccharide produced by xanthomonas campestris strain 642 was synthesized as its methyl glycoside via 3-o-selective glycosylation of methyl alpha-l-rhamnopyranosyl-(1-->3)-2,4-di-o-benzoyl-alpha-l-rhamnopyranoside (9) with 2,3,4-tri-o-benzoyl-alpha-l-rhamnopyranosyl-(1-->3)-2,4-di-o-benzoyl-alpha-l-rhamnopyranosyl-( ...200312706967
characterization of dominantly negative mutant clya cytotoxin proteins in escherichia coli.we report studies of the subcellular localization of the clya cytotoxic protein and of mutations causing defective translocation to the periplasm in escherichia coli. the ability of clya to translocate to the periplasm was abolished in deletion mutants lacking the last 23 or 11 amino acid residues of the c-terminal region. a naturally occurring clya variant lacking four residues (183 to 186) in a hydrophobic subdomain was retained mainly in the cytosolic fraction. these mutant proteins displayed ...200312949101
glutathione and catalase provide overlapping defenses for protection against respiration-generated hydrogen peroxide in haemophilus influenzae.glutathione is an abundant and ubiquitous low-molecular-weight thiol that may play a role in many cellular processes, including protection against the deleterious effects of reactive oxygen species. we address here the role of glutathione in protection against hydrogen peroxide (h2o2) in haemophilus influenzae and show that glutathione and catalase provide overlapping defense systems. h. influenzae is naturally glutathione deficient and imports glutathione from the growth medium. mutant h. influ ...200312949108
evolution of mosaic operons by horizontal gene transfer and gene displacement in situ.shuffling and disruption of operons and horizontal gene transfer are major contributions to the new, dynamic view of prokaryotic evolution. under the 'selfish operon' hypothesis, operons are viewed as mobile genetic entities that are constantly disseminated via horizontal gene transfer, although their retention could be favored by the advantage of coregulation of functionally linked genes. here we apply comparative genomics and phylogenetic analysis to examine horizontal transfer of entire opero ...200312952534
biofilm dispersal in xanthomonas campestris is controlled by cell-cell signaling and is required for full virulence to plants.the rpf gene cluster of xanthomonas campestris pathovar campestris (xcc) is required for the pathogenesis of this bacterium to plants. several rpf genes are involved in the coordinate positive regulation of the production of virulence factors mediated by the small diffusible molecule dsf (for diffusible signal factor). rpff directs the synthesis of dsf, and a two-component sensory transduction system comprising rpfc and rpfg has been implicated in the perception of the dsf signal and signal tran ...200312960398
evidence for dose-dependent effects on plant growth by stenotrophomonas strains from different origins.to assess the influence of stenotrophomonas on plants, the interaction of 16 stenotrophomonas strains from clinical and environmental sources with strawberry plant seedlings was analysed.200312969277
effect of azospirillum-mediated plant growth promotion on the development of bacterial diseases on fresh-market and cherry tomato.plant growth-promoting (pgp) activity of two azospirillum strains and their effects on foliar and vascular bacterial diseases were evaluated on fresh market and cherry tomato.200312969298
a developmental response to pathogen infection in arabidopsis.we present evidence that susceptible arabidopsis plants accelerate their reproductive development and alter their shoot architecture in response to three different pathogen species. we infected 2-week-old arabidopsis seedlings with two bacterial pathogens, pseudomonas syringae and xanthomonas campestris, and an oomycete, peronospora parasitica. infection with each of the three pathogens reduced time to flowering and the number of aerial branches on the primary inflorescence. in the absence of co ...200312970499
an improved probability mapping approach to assess genome mosaicism.maximum likelihood and posterior probability mapping are useful visualization techniques that are used to ascertain the mosaic nature of prokaryotic genomes. however, posterior probabilities, especially when calculated for four-taxon cases, tend to overestimate the support for tree topologies. furthermore, because of poor taxon sampling four-taxon analyses suffer from sensitivity to the long branch attraction artifact. here we extend the probability mapping approach by improving taxon sampling o ...200312974984
vgj phi, a novel filamentous phage of vibrio cholerae, integrates into the same chromosomal site as ctx phi.we describe a novel filamentous phage, designated vgj phi, isolated from strain sg25-1 of vibrio cholerae o139, which infects all o1 (classical and el tor) and o139 strains tested. the sequence of the 7,542 nucleotides of the phage genome reveals that vgj phi has a distinctive region of 775 nucleotides and a conserved region with an overall genomic organization similar to that of previously characterized filamentous phages, such as ctx phi of v. cholerae and ff phages of escherichia coli. the co ...200313129939
application of comparative genomics in the identification and analysis of novel families of membrane-associated receptors in bacteria.a great diversity of multi-pass membrane receptors, typically with 7 transmembrane (tm) helices, is observed in the eukaryote crown group. so far, they are relatively rare in the prokaryotes, and are restricted to the well-characterized sensory rhodopsins of various phototropic prokaryotes.200312914674
[on the development of resistance in erwinia carotovora (jones) holland and xanthomonas campestris (pammel) dowson to thiosulfate ethers]. 196314048461
8-hydroxy-(+)-delta-cadinene is a precursor to hemigossypol in gossypium hirsutum.[(3)h](+)-delta-cadinene and its 8-hydroxy derivative, prepared from (1rs)-[1-(3)h]fpp by the action of one and two recombinant enzymes, respectively, were infiltrated into cotyledons of bacterial blight-resistant cotton plants as they biosynthesized sesquiterpene phytoalexins in response to infection by xanthomonas campestris pv. malvacearum. following both treatments, tritium appeared in the hplc fraction that contained hemigossypol. hemigossypol was isolated from the cotyledons that had been ...200312946420
flagellin gene flic of xanthomonas campestris is upregulated by transcription factor clp.clp, a homologue of cyclic amp receptor protein (crp), of xanthomonas campestris regulates the expression of many genes. in this study, proteomic analysis showed the amounts of several extracellular proteins in a clp mutant to be reduced, including the flagellin encoded by flic. transcriptional fusion assay showed that activity of flic promoter is reduced by 2.3-fold in clp mutant compared to the wild-type, coincident with the protein levels. the clp mutant is slightly reduced in motility; howev ...200312893272
similarity of xanthomonas and pseudomonas deoxyribonucleic acid.de ley, j. (state university, ghent, belgium), and s. friedman. similarity of xanthomonas and pseudomonas deoxyribonucleic acid. j. bacteriol. 89:1306-1309. 1965.-pronounced deoxyribonucleic acid (dna) hybridization was detected with the dna-agar method within the group of xanthomonas and between xanthomonas and pseudomonas. sheared, denatured c(14)-dna from x. pelargonii hybridized 80 to 100% with high molecular weight, denatured agar-bound dna from eight different xanthomonas nomenspecies. the ...196514293002
the complete genome sequence of chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability.chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) approximately 500 orfs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) widespread utilization of quorum sensing for control of inducible systems, all of ...200314500782
[changes in some biological properties of xanthomonas campestris under the influence of thiosulfonic acid esters. i. changes in morphological, biochemical and serological properties of x. campestris]. 196114460452
the unusual arabidopsis extensin gene atext1 is expressed throughout plant development and is induced by a variety of biotic and abiotic stresses.we detail the expression of the arabidopsis thaliana (l.) heynh. atext1 extensin gene. atext1 is normally expressed in roots and inflorescences, and is induced by wounding, exogenously supplied salicylic acid, methyl jasmonate, auxins and brassinosteroids. northern assays and histochemical analysis of transgenics expressing an atext1:: gus fusion show that this gene is also induced by the brassica pathogen xanthomonas campestris pv. campestris and that this induction is restricted to tissues clo ...200314520562
cleavage of the pseudomonas syringae type iii effector avrrpt2 requires a host factor(s) common among eukaryotes and is important for avrrpt2 localization in the host cell.many phytopathogenic bacteria use a type iii secretion system to deliver type iii effector proteins into the host plant cell. the pseudomonas syringae type iii effector avrrpt2 is cleaved at a specific site when translocated into the host cell. in this study, we first demonstrate that the factor(s) required for avrrpt2 cleavage is present in extracts from animal and yeast cells, as well as plant cells. the cleavage factor in animal and plant cell extracts was heat labile but relatively insensiti ...200314526114
[the extracellular proteases of the phytopathogenic bacterium xanthomonas campestris].the culture liquids of three xanthomonas campestris pv. campestris strains were found to possess proteolytic activity. the culture liquid of strain b-611 with the highest proteolytic activity was fractionated by salting-out with ammonium sulfate, gel filtration, and ion-exchange chromatography. the electrophoretic analysis of active fractions showed the presence of two proteases in the culture liquid of strain b-611, the major of which being serine protease. the treatment of cabbage seedlings wi ...200314526540
influence of nutritional factors on the nature, yield, and composition of exopolysaccharides produced by gluconacetobacter xylinus i-2281.the influence of substrate composition on the yield, nature, and composition of exopolysaccharides (eps) produced by the food-grade strain gluconacetobacter xylinus i-2281 was investigated during controlled cultivations on mixed substrates containing acetate and either glucose, sucrose, or fructose. enzymatic activity analysis and acid hydrolysis revealed that two eps, gluconacetan and levan, were produced by g. xylinus. in contrast to other acetic acid strains, no exocellulose formation has bee ...200314532066
prospecting for novel biocatalysts in a soil metagenome.the metagenomes of complex microbial communities are rich sources of novel biocatalysts. we exploited the metagenome of a mixed microbial population for isolation of more than 15 different genes encoding novel biocatalysts by using a combined cultivation and direct cloning strategy. a 16s rrna sequence analysis revealed the presence of hitherto uncultured microbes closely related to the genera pseudomonas, agrobacterium, xanthomonas, microbulbifer, and janthinobacterium. total genomic dna from t ...200314532085
xanthan gum: production, recovery, and properties.xanthan gum is a microbial polysaccharide of great commercial significance. this review focuses on various aspects of xanthan production, including the producing organism xanthomonas campestris, the kinetics of growth and production, the downstream recovery of the polysaccharide, and the solution properties of xanthan.200014538095
the molecular genetics of virulence of xanthomonas campestris.bacteria belonging to the genus xanthomonas are important pathogens of many plants, and their virulence appears to be due primarily to secreted and surface compounds that could increase host nutrient loss, or avoid or suppress unfavorable conditions in the host. type ii and iii secretory pathways are essential for virulence. some individual extracellular enzymes (type ii-secretion dependent) affect final bacterial population levels, whereas some avirulence gene products (type iii-secretion depen ...199914538126
multiple hormones act sequentially to mediate a susceptible tomato pathogen defense response.phytohormones regulate plant responses to a wide range of biotic and abiotic stresses. how a limited number of hormones differentially mediate individual stress responses is not understood. we have used one such response, the compatible interaction of tomato (lycopersicon esculentum) and xanthomonas campestris pv vesicatoria (xcv), to examine the interactions of jasmonic acid (ja), ethylene, and salicylic acid (sa). the role of ja was assessed using an antisense allene oxide cyclase transgenic l ...200314551324
[on the biological properties of the pathogen of cabbage bacteriosis xanthomonas campestris]. 196113755078
[changes of some biological properties of xanthomonas campestris under the influence of thiosulfonic acid esters. ii. change of the virulence of x. campestris]. 196214460453
high throughput virus-induced gene silencing implicates heat shock protein 90 in plant disease resistance.virus-induced gene silencing was used to assess the function of random nicotiana benthamiana cdnas in disease resistance. out of 4992 cdnas tested from a normalized library, there were 79 that suppressed a hypersensitive response (hr) associated with pto-mediated resistance against pseudomonas syringae. however, only six of these clones blocked the pto-mediated suppression of p.syringae growth. the three clones giving the strongest loss of pto resistance had inserts corresponding to hsp90 and al ...200314592968
identification and characterization of a unique adenosine kinase from mycobacterium tuberculosis.adenosine kinase (ak) is a purine salvage enzyme that catalyzes the phosphorylation of adenosine to amp. in mycobacterium tuberculosis, ak can also catalyze the phosphorylation of the adenosine analog 2-methyladenosine (methyl-ado), the first step in the metabolism of this compound to an active form. purification of ak from m. tuberculosis yielded a 35-kda protein that existed as a dimer in its native form. adenosine (ado) was preferred as a substrate at least 30-fold (km = 0.8 +/- 0.08 microm) ...200314594827
flagellin glycosylation island in pseudomonas syringae pv. glycinea and its role in host specificity.the deduced amino acid sequences of the flagellins of pseudomonas syringae pv. tabaci and p. syringae pv. glycinea are identical; however, their abilities to induce a hypersensitive reaction are clearly different. the reason for the difference seems to depend on the posttranslational modification of the flagellins. to investigate the role of this posttranslational modification in the interactions between plants and bacterial pathogens, we isolated genes that are potentially involved in the postt ...200314594840
phya, a secreted protein of xanthomonas oryzae pv. oryzae, is required for optimum virulence and growth on phytic acid as a sole phosphate source.xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. we have identified a novel virulence deficient mutant (bxo1691) of x. oryzae pv. oryzae that has a tn5 insertion in an open reading frame (phya; putative phytase a) encoding a 373-amino acid (aa) protein containing a 28-aa predicted signal peptide. extracellular protein profiles revealed that a 38-kda band is absent in phya mutants as compared with phya+ strains. a blast search with phya and its deduced polype ...200314601665
activity of class iii peroxidases in the defense of cotton to bacterial blight.cotton cotyledons displayed a hypersensitive reaction (hr) in the cultivar réba b50 after infiltration with the avirulent race 18 from xanthomonas campestris pv. malvacearum. two sets of peroxidases were associated with the hr time course. early but transient accumulation of peroxidase in material encapsulating the bacteria in intercellular areas was observed by immunocytochemistry at 3 h postinfection and coincided with the oxidative burst. total guaiacol-peroxidase activity was highly increase ...200314601671
gene essentiality determines chromosome organisation in bacteria.in escherichia coli and bacillus subtilis, essentiality, not expressivity, drives the distribution of genes between the two replicating strands. although essential genes tend to be coded in the leading replicating strand, the underlying selective constraints and the evolutionary extent of these findings have still not been subject to comparative studies. here, we extend our previous analysis to the genomes of low g + c firmicutes and gamma-proteobacteria, and in a second step to all sequenced ba ...200314602916
xanthomonas type iii effector xopd targets sumo-conjugated proteins in planta.xanthomonas campestris pathovar vesicatoria (xcv) uses the type iii secretion system (ttss) to inject effector proteins into cells of solanaceous plants during pathogenesis. a number of xcv ttss effectors have been identified; however, their function in planta remains elusive. here, we provide direct evidence for a functional role for a phytopathogenic bacterial ttss effector in planta by demonstrating that the xcv effector xopd encodes an active cysteine protease with plant-specific sumo substr ...200314617166
identification and characterization of genes required for biosynthesis and transport of the siderophore vibrioferrin in vibrio parahaemolyticus.in response to low iron availability, vibrio parahaemolyticus synthesizes and secretes a polyhydroxycarboxylate-type siderophore vibrioferrin which is composed of 1 mol each of 2-ketoglutaric acid, l-alanine, ethanolamine, and citric acid. we have previously reported the cloning and characterization of the pvua gene, which encodes the 78-kda outer membrane receptor protein for ferric vibrioferrin. in this study, nine genes involved in the biosynthesis and transport of vibrioferrin have been iden ...200314617658
folm, a new chromosomally encoded dihydrofolate reductase in escherichia coli.escherichia coli (thya deltafola) mutants are viable and can grow in minimal medium when supplemented with thymidine alone. here we present evidence from in vivo and in vitro studies that the ydgb gene determines an alternative dihydrofolate reductase that is related to the trypanosomatid pteridine reductases. we propose to rename this gene folm.200314617668
fimx, a multidomain protein connecting environmental signals to twitching motility in pseudomonas aeruginosa.twitching motility is a form of surface translocation mediated by the extension, tethering, and retraction of type iv pili. three independent tn5-b21 mutations of pseudomonas aeruginosa with reduced twitching motility were identified in a new locus which encodes a predicted protein of unknown function annotated pa4959 in the p. aeruginosa genome sequence. complementation of these mutants with the wild-type pa4959 gene, which we designated fimx, restored normal twitching motility. fimx mutants we ...200314645265
xopc and xopj, two novel type iii effector proteins from xanthomonas campestris pv. vesicatoria.pathogenicity of the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria depends on a type iii secretion (tts) system which translocates bacterial effector proteins into the plant cell. previous transcriptome analysis identified a genome-wide regulon of putative virulence genes that are coexpressed with the tts system. in this study, we characterized two of these genes, xopc and xopj. both genes encode xanthomonas outer proteins (xops) that were shown to be secreted by the tts sy ...200314645268
novel type of specialized transduction for ctx phi or its satellite phage rs1 mediated by filamentous phage vgj phi in vibrio cholerae.the main virulence factor of vibrio cholerae, the cholera toxin, is encoded by the ctxab operon, which is contained in the genome of the lysogenic filamentous phage ctx phi. this phage transmits ctxab genes between v. cholerae bacterial populations that express toxin-coregulated pilus (tcp), the ctx phi receptor. in investigating new forms of ctxab transmission, we found that v. cholerae filamentous phage vgj phi, which uses the mannose-sensitive hemagglutinin (msha) pilus as a receptor, transmi ...200314645284
legume symbiotic nitrogen fixation by beta-proteobacteria is widespread in nature.following the initial discovery of two legume-nodulating burkholderia strains (l. moulin, a. munive, b. dreyfus, and c. boivin-masson, nature 411:948-950, 2001), we identified as nitrogen-fixing legume symbionts at least 50 different strains of burkholderia caribensis and ralstonia taiwanensis, all belonging to the beta-subclass of proteobacteria, thus extending the phylogenetic diversity of the rhizobia. r. taiwanensis was found to represent 93% of the mimosa isolates in taiwan, indicating that ...200314645288
recognition of individual genes in a single bacterial cell by fluorescence in situ hybridization--ring-fish.fluorescence in situ hybridization (fish) using rrna targeted oligonucleotide probes is a standard method for identification of microorganisms in environmental samples. apart from its value as a phylogenetic marker ribosomal rna has always been the favoured target molecule for fish because of its abundance in all cells, whereas plasmids and dna were regarded as unsuitable targets because of their low copy number. here we present an improved fish technique, which is based on polynucleotide probes ...200414651613
whole genome shotgun sequencing guided by bioinformatics pipelines--an optimized approach for an established technique.while the sequencing of bacterial genomes has become a routine procedure at major sequencing centers, there are still a number of genome projects at small- or medium-size facilities. for these facilities a maximum of control over sequencing, assembling and finishing is essential. at the same time, facilities have to be able to co-operate at minimum costs for the overall project. we have established a pipeline for the distributed sequencing of alcanivorax borkumensis sk2, azoarcus sp. bh72, clavi ...200314651855
comparison of two xanthomonas campestris pathovar campestris genomes revealed differences in their gene composition.for the xanthomonas campestris pathovar campestris wild-type strain b100 a plasmid-based clone library was constructed. the plasmids carried chromosomal fragments of 3-4 kb in size that were tagged in vitro with the artificial transposon kan-2. more than 3000 of the transposon target sites were characterized by dna sequencing. the sequences obtained were compared to the recently published genome of xanthomonas campestris pathovar campestris strain atcc 33913. most of the sequenced clones derived ...200314651861
genomic approaches in xanthomonas campestris pv. vesicatoria allow fishing for virulence genes.xanthomonas campestris pv. vesicatoria is an economically important pathogen of pepper and tomato and has been established as a model organism to study bacterial infection strategies. in the last two decades, intensive genetic and molecular analyses led to the isolation of many genes that play a role in the intimate molecular relationship with the host plant. essential for pathogenicity is a type iii protein secretion system, which delivers bacterial effector proteins into the host cell. current ...200314651862
new connections in the prokaryotic toxin-antitoxin network: relationship with the eukaryotic nonsense-mediated rna decay system.several prokaryotic plasmids maintain themselves in their hosts by means of diverse post-segregational cell killing systems. recent findings suggest that chromosomally encoded copies of toxins and antitoxins of post-segregational cell killing systems - such as the rele system - might function as regulatory switches under stress conditions. the rele toxin cleaves ribosome-associated transcripts, whereas another post-segregational cell killing toxin, pare, functions as a gyrase inhibitor.200314659018
metagenome survey of biofilms in drinking-water networks.most naturally occurring biofilms contain a vast majority of microorganisms which have not yet been cultured, and therefore we have little information on the genetic information content of these communities. therefore, we initiated work to characterize the complex metagenome of model drinking water biofilms grown on rubber-coated valves by employing three different strategies. first, a sequence analysis of 650 16s rrna clones indicated a high diversity within the biofilm communities, with the ma ...200314660379
concomitant induction of systemic resistance to pseudomonas syringae pv. lachrymans in cucumber by trichoderma asperellum (t-203) and accumulation of phytoalexins.most studies on the reduction of disease incidence in soil treated with trichoderma asperellum have focused on microbial interactions rather than on plant responses. this study presents conclusive evidence for the induction of a systemic response against angular leaf spot of cucumber (pseudomonas syringae pv. lachrymans) following application of t. asperellum to the root system. to ascertain that t. asperellum was the only microorganism present in the root milieu, plants were grown in an aseptic ...200314660384
the tomato resistance protein bs4 is a predicted non-nuclear tir-nb-lrr protein that mediates defense responses to severely truncated derivatives of avrbs4 and overexpressed avrbs3.the lycopersicon esculentum bs4 resistance (r) gene specifies recognition of xanthomonas campestris pv. vesicatoria (xcv) strains that express the cognate avrbs4 avirulence protein. bs4 was isolated by positional cloning and is predicted to encode a nucleotide-binding leucine-rich repeat (nb-lrr) protein that is homologous to tobacco n and potato y-1 resistance proteins. xcv infection tests demonstrate that bs4 confers perception of avrbs4 but not the 97% identical avrbs3 protein. however, when ...200414675431
a nuclear protease required for flowering-time regulation in arabidopsis reduces the abundance of small ubiquitin-related modifier conjugates.the arabidopsis mutant early in short days4 (esd4) shows extreme early flowering and alterations in shoot development. we have identified esd4 and demonstrate that it encodes a nuclear protein located predominantly at the periphery of the nucleus. esd4 contains a segment of >200 amino acids with strong similarity to yeast and animal proteases that are specific for the protein modifier small ubiquitin-related modifier (sumo). esd4 shows a similar function to these proteases in vitro and processes ...200314507998
involvement of an inducible fructose phosphotransferase operon in streptococcus gordonii biofilm formation.oral streptococci, such as streptococcus gordonii, are the predominant early colonizers that initiate biofilm formation on tooth surfaces. investigation of an s. gordonii::tn917-lac biofilm-defective mutant isolated by using an in vitro biofilm formation assay showed that the transposon insertion is near the 3' end of an open reading frame (orf) encoding a protein homologous to streptococcus mutans fruk. three genes, frur, fruk, and frui, were predicted to encode polypeptides that are part of th ...200314563858
role of siderophore biosynthesis in virulence of staphylococcus aureus: identification and characterization of genes involved in production of a siderophore.molecular determinants underlying the production of siderophores in the human and animal pathogen staphylococcus aureus and the contribution of siderophore production to the virulence of this bacterium have, until now, remained undefined. here, we show that s. aureus strains rn6390 and newman produce siderophore when the cells are starved for iron. we further identified and characterized a nine-gene, iron-regulated operon, designated sbn and situated between sirabc and gale on the s. aureus chro ...200414688077
cadmium-induced adaptive resistance and cross-resistance to zinc in xanthomonas campestris.cadmium (cd) and zinc (zn) are environmental pollutants affecting both soil and water. the toxicity resulting from the exposure of xanthomonas campestris, a soil bacterium and plant pathogen, to these metals was investigated. pretreatment of x. campestris with sub-lethal concentrations of cd induced adaptive protection against subsequent exposure to lethal doses of cd. moreover, cd-induced cells also showed cross-resistance to lethal concentrations of zn. these induced protections required newly ...200314570280
constitutive expression of a chromosomal class a (bjm group 2) beta-lactamase in xanthomonas campestris.sequencing of the upstream region of the beta-lactamase gene from xanthomonas campestris pv. campestris 11 (bla(xcc-1)) revealed the cognate ampr1 gene (289 amino acids, 31 kda). it runs divergently from bla(xcc-1) with a 100-bp intergenic region (ig) containing partially overlapped promoters with structural features typical of the bla-ampr ig. the deduced ampr1 protein shows significant identity in amino acid sequence and conserved motifs with ampr proteins of other species, e.g., of pseudomona ...200414693541
osmoregulatory systems of escherichia coli: identification of betaine-carnitine-choline transporter family member betu and distributions of betu and trkg among pathogenic and nonpathogenic isolates.multiple transporters mediate osmoregulatory solute accumulation in escherichia coli k-12. the larger genomes of naturally occurring strains such as pyelonephritis isolates cft073 and hu734 may encode additional osmoregulatory systems. cft073 is more osmotolerant than hu734 in the absence of organic osmoprotectants, yet both strains grew in high osmolality medium at low k(+) (micromolar concentrations) and retained locus trkh, which encodes an osmoregulatory k(+) transporter. both lacked the trk ...200414702297
the hwe histidine kinases, a new family of bacterial two-component sensor kinases with potentially diverse roles in environmental signaling.two-component signal transduction pathways play a major role in the response of bacteria to external cues. these pathways are initiated by large collection of histidine kinases (hks) containing a sensor domain that perceives the environmental signal followed by an hk domain that triggers a histidine-aspartate phosphorelay. previous phylogenetic analyses identified 11 major families of two-component hks by comparing signature motifs within the hk domain. here we describe a new family with homolog ...200414702314
sequence analysis of the mobile genome island pklc102 of pseudomonas aeruginosa c.the pseudomonas aeruginosa plasmid pklc102 coexists as a plasmid and a genome island in clone c strains. whereas the related plasmid pklk106 reversibly recombines with p. aeruginosa clone k chromosomes at one of the two trna(lys) genes, pklc102 is incorporated into the trna(lys) gene only close to the pila locus. targeting of the other trna(lys) copy in the chromosome is blocked by a 23,395-bp mosaic of truncated pao open reading frames, transposons, and pklc102 homologs. annotation and phylogen ...200414702321
pseudomonas syringae type iii secretion system targeting signals and novel effectors studied with a cya translocation reporter.pseudomonas syringae pv. tomato strain dc3000 is a pathogen of tomato and arabidopsis: the hrp-hrc-encoded type iii secretion system (ttss), which injects bacterial effector proteins (primarily called hop or avr proteins) into plant cells, is required for pathogenicity. in addition to being regulated by the hrpl alternative sigma factor, most avr or hop genes encode proteins with n termini that have several characteristic features, including (i) a high percentage of ser residues, (ii) an aliphat ...200414702323
pathogenicity islands in bacterial pathogenesis.in this review, we focus on a group of mobile genetic elements designated pathogenicity islands (pai). these elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. characteristic molecular features of pai of important human pathogens and their role in pathogenesis are described. the availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a ...200414726454
crystallization and preliminary x-ray crystallographic analysis of the n-terminal domain of xpse protein from xanthomonas campestris, an essential component of the type ii protein-secretion machinery.secretion of pre-folded extracellular proteins across the outer membrane of gram-negative bacteria is mainly assisted by the type ii secretion machinery composed of 12-15 proteins. here, the crystallization and preliminary analysis of one of the essential components of xanthomonas campestris secretion machinery, the 21 kda n-terminal domain of xpse protein (xpse(n)), are reported. xpse(n) has been crystallized at 277 k using peg 400 as precipitant. these crystals belong to the tetragonal space g ...200414684906
pathogenesis-related protein 10 isolated from hot pepper functions as a ribonuclease in an antiviral pathway.a hot pepper (capsicum annuum) cdna clone encoding pathogenesis-related protein 10 (capr-10) was isolated by differential screening of a cdna library prepared from pepper leaves inoculated with tobacco mosaic virus pathotype (tmv-p0). capr-10 transcripts were induced in the incompatible interaction with tmv-p0 or xanthomonas campestris pv. vesicatoria (xcv) but not induced in the compatible interaction. characterization of enzymatic properties of capr-10 indicated that the recombinant protein ex ...200414690503
lempk3 is a mitogen-activated protein kinase with dual specificity induced during tomato defense and wounding responses.mitogen-activated protein (map) kinase cascades are readily activated during the response of plants to avirulent pathogens or to pathogen-derived elicitors. here we show that the tomato map kinase lempk3 is specifically induced at the mrna level during elicitation of the hypersensitive response in resistant plants infected by avirulent strains of the phytopathogenic bacteria xanthomonas campestris pv. vesicatoria and pseudomonas syringae pv. tomato, as well as upon treatment with the fungal elic ...200414742423
characterization of the 101-kilobase-pair megaplasmid pkb1, isolated from the rubber-degrading bacterium gordonia westfalica kb1.the complete sequence of the circular 101,016-bp megaplasmid pkb1 from the cis-1,4-polyisoprene-degrading bacterium gordonia westfalica kb1, which represents the first described extrachromosomal dna of a member of this genus, was determined. plasmid pkb1 harbors 105 open reading frames. the predicted products of 46 of these are significantly related to proteins of known function. plasmid pkb1 is organized into three functional regions that are flanked by insertion sequence (is) elements: (i) a r ...200414679241
distribution and phylogenetic analysis of family 19 chitinases in actinobacteria.in organisms other than higher plants, family 19 chitinase was first discovered in streptomyces griseus hut6037, and later, the general occurrence of this enzyme in streptomyces species was demonstrated. in the present study, the distribution of family 19 chitinases in the class actinobacteria and the phylogenetic relationship of actinobacteria family 19 chitinases with family 19 chitinases of other organisms were investigated. forty-nine strains were chosen to cover almost all the suborders of ...200414766598
importance of opghxcv of xanthomonas campestris pv. vesicatoria in host-parasite interactions.tn5 insertion mutants of xanthomonas campestris pv. vesicatoria were inoculated into tomato and screened for reduced virulence. one mutant exhibited reduced aggressiveness and attenuated growth in planta. southern blot analyses indicated that the mutant carried a single tn5 insertion not associated with previously cloned pathogenicity-related genes of x. campestris pv. vesicatoria. the wild-type phenotype of this mutant was restored by one recombinant plasmid (popg361) selected from a genomic li ...200414964529
functional characterization of gumk, a membrane-associated beta-glucuronosyltransferase from xanthomonas campestris required for xanthan polysaccharide synthesis.xanthomonas campestris is a gram-negative bacterium that produces an exopolysaccharide known as xanthan gum. xanthan is involved in a variety of biological functions, including pathogenesis, and is widely used in the industry as thickener and viscosifier. although the genetics and biosynthetic process of xanthan are well documented, the enzymatic components have not been examined and no data on glycosyltransferases have been reported. we describe the functional characterization of the gumk gene ...200414736729
antifungal activity of beta-asarone from rhizomes of acorus gramineus.an antifungal substance was isolated from the extract of acorus gramineus using various chromatographic procedures. the antibiotic was identified as beta-asarone, cis-2,4,5-trimethoxy-1-propenylbenzene, on the basis of the high-resolution ei-mass, nmr, and uv spectral data. beta-asarone completely inhibited mycelial growth of some plant pathogenic fungi, cladosporium cucumerinum,colletotrichum orbiculare, magnaporthe grisea, and pythium ultimum, in a range of 0.5-30 microg/ml. the growth of baci ...200414969530
cell-cell signaling controls xylella fastidiosa interactions with both insects and plants.xylella fastidiosa, which causes pierce's disease of grapevine and other important plant diseases, is a xylem-limited bacterium that depends on insect vectors for transmission. although many studies have addressed disease symptom development and transmission of the pathogen by vectors, little is known about the bacterial mechanisms driving these processes. recently available x. fastidiosa genomic sequences and molecular tools have provided new routes for investigation. here, we show that a diffu ...200414755059
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