Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| functional analysis of gapped microbial genomes: amino acid metabolism of thiobacillus ferrooxidans. | a gapped genome sequence of the biomining bacterium thiobacillus ferrooxidans strain atcc23270 was assembled from sheared dna fragments (3.2-times coverage) into 1,912 contigs. a total of 2,712 potential genes (orfs) were identified in 2.6 mbp (megabase pairs) of thiobacillus genomic sequence. of these genes, 2,159 could be assigned functions by using the wit-pro/emp genome analysis system, most with a high degree of certainty. nine hundred of the genes have been assigned roles in metabolic path ... | 2000 | 10737802 |
| superoxide dismutase activity in pseudomonas putida affects utilization of sugars and growth on root surfaces. | to investigate the role of superoxide dismutases (sod) in root colonization and oxidative stress, mutants of pseudomonas putida lacking manganese-superoxide dismutase (mnsod) (soda), iron-superoxide dismutase (fesod) (sodb), or both were generated. the soda sodb mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. the sodb and soda sodb mutants were more sensitive than wild type to oxidative stress generated within the cell by paraquat treatment. in sing ... | 2000 | 10742227 |
| mutants of xanthomonas oryzae pv. oryzae deficient in general secretory pathway are virulence deficient and unable to secrete xylanase. | xanthomonas oryzae pv. oryzae (xoo) causes bacterial leaf blight, a serious disease of rice. a virulence- and xylanase-deficient mutant of xoo was isolated following ethyl methane sulfonate (ems) mutagenesis. a cosmid clone that restored virulence and xylanase secretion was obtained from a genomic library by functional complementation. transposon mutagenesis and marker exchange studies revealed genes on the cloned dna that were required for xylanase production and virulence. sequence analysis wi ... | 2000 | 10755302 |
| genotypic characterization of xanthomonad strains isolated from passion fruit plants (passiflora spp.) and their relatedness to different xanthomonas species. | the genetic diversity of 55 xanthomonad strains isolated from passion fruit plants (passiflora spp.) and identified as xanthomonas campestris pv. passiflorae was initially assessed by randomly amplified polymorphic dna (rapd) analysis. the strains showed a high level of polymorphism with almost unique fingerprints. fifteen clusters with a similarity of approximately 70% were identified, three of which were prevalent. there was a correlation between the clusters and the geographic origin of the s ... | 2000 | 10758892 |
| [rapd-markers linked to the locus for resistance to the race 4 pathogen for black rot, xanthomonas campestris pv. campestris (pamm.) dow., in brassica rapa l]. | association between the rapd markers and the resistance to race 4 of the black rot causative agent was studied in brassica rapa l. experiments were carried out using doubled haploid lines, obtained via crosses between the race 4-susceptible fodder turnip and resistant pak-choi, and the f2 progeny of the crosses between the doubled haploid lines with contrasting resistance. the we(22)980 rapd marker inherited from the pak-choi and associated with the clubroot susceptibility was also linked to the ... | 2000 | 10779910 |
| the pseudomonas syringae hrp pathogenicity island has a tripartite mosaic structure composed of a cluster of type iii secretion genes bounded by exchangeable effector and conserved effector loci that contribute to parasitic fitness and pathogenicity in plants. | the plant pathogenic bacterium pseudomonas syringae is divided into pathovars differing in host specificity, with p. syringae pv. syringae (psy) and p. syringae pv. tomato (pto) representing particularly divergent pathovars. p. syringae hrp/hrc genes encode a type iii protein secretion system that appears to translocate avr and hop effector proteins into plant cells. dna sequence analysis of the hrp/hrc regions in psy 61, psy b728a, and pto dc3000 has revealed a hrp pathogenicity island (pai) wi ... | 2000 | 10781092 |
| prephenate dehydratase from the aphid endosymbiont (buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibition by phenylalanine. | buchnera aphidicola, the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. we have cloned and sequenced a region of the genome of b. aphidicola isolated from acyrthosiphon pisum which includes the two-domain aroq/phea gene. this gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l-phenylalanine biosynthesis. two changes involved in the overproduction of ... | 2000 | 10781569 |
| structure of the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. manihotis gspb 2755 and gspb 2364. | the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. manihotis strains gspb 2755 and gspb 2364 was studied by sugar and methylation analyses and 1h and 13c nmr spectroscopy, including 2d cosy, tocsy, noesy, and h-detected 1h, 13c heteronuclear multiple-quantum coherence (hmqc) experiments. the polysaccharide was found to contain l-rhamnose and l-xylose in the ratio 3:1, and the following structure of the tetrasaccharide repeating unit was established: [formula: see ... | 2000 | 10782308 |
| novel genes involved in the regulation of pathogenicity factor production within the rpf gene cluster of xanthomonas campestris. | the synthesis of extracellular enzymes and extracellular polysaccharide (eps) in xanthomonas campestris pathovar campestris (xcc) is subject to co-ordinate regulation by a cluster of genes called rpf (for regulation of pathogenicity factors). these genes are located within a 21.9 kb region of the chromosome isolated as the cosmid clone pij3020. the genes in the left-hand section of this region of the chromosome have previously been characterized. this paper reports on the genes in the right-hand ... | 2000 | 10784047 |
| design and evaluation of a lactobacillus manihotivorans species-specific rrna-targeted hybridization probe and its application to the study of sour cassava fermentation. | based on 16s rrna sequence comparison, we have designed a 20-mer oligonucleotide that targets a region specific to the species lactobacillus manihotivorans recently isolated from sour cassava fermentation. the probe recognized the rrna obtained from all the l. manihotivorans strains tested but did not recognize 56 strains of microorganisms from culture collections or directly isolated from sour cassava, including 29 species of lactic acid bacteria. this probe was then successfully used in quanti ... | 2000 | 10788405 |
| identification of the pgmg gene, encoding a bifunctional protein with phosphoglucomutase and phosphomannomutase activities, in the gellan gum-producing strain sphingomonas paucimobilis atcc 31461. | the pgmg gene of sphingomonas paucimobilis atcc 31461, the industrial gellan gum-producing strain, was cloned and sequenced. it encodes a 50,059-da polypeptide that has phosphoglucomutase (pgm) and phosphomannomutase (pmm) activities and is 37 to 59% identical to other bifunctional proteins with pgm and pmm activities from gram-negative species, including pseudomonas aeruginosa algc. purified pgmg protein showed a marked preference for glucose-1-phosphate (g1p); the catalytic efficiency was abou ... | 2000 | 10788412 |
| the tomato ethylene receptors nr and leetr4 are negative regulators of ethylene response and exhibit functional compensation within a multigene family. | the plant hormone ethylene is involved in many developmental processes, including fruit ripening, abscission, senescence, and leaf epinasty. tomato contains a family of ethylene receptors, designated leetr1, leetr2, nr, leetr4, and leetr5, with homology to the arabidopsis etr1 ethylene receptor. transgenic plants with reduced leetr4 gene expression display multiple symptoms of extreme ethylene sensitivity, including severe epinasty, enhanced flower senescence, and accelerated fruit ripening. the ... | 2000 | 10792050 |
| genetic polymorphism in xanthomonas albilineans strains originating from 11 geographical locations, revealed by two dna probes. | two dna fragments from xanthomonas albilineans were used as probes to study the molecular diversity among strains of this pathogen. two serologically distinct groups, serovars i and ii, could be differentiated by hybridization to the probes. these probes, designated 830 and 838, were cloned after subtractive dna hybridization of common sequences of xanthomonas campestris pv. vasculorum from a serovar i strain of x. albilineans. they did not hybridize to the dna of several other xanthomonads or t ... | 2000 | 10792648 |
| structure elucidation of the o-chain from the major lipopolysaccharide of the xanthomonas campestris strain 642. | a novel o-polysaccharide consisting of d-xylp and l-rhap in the molar ratio of 1:2.5 was identified as the major component in the lipopolysaccharide fraction of xanthomonas campestris strain 642, which is responsible for a new bacterial disease of the strawberry plant. its structure was mainly determined using chemical analysis, smith degradation and 1d and 2d nmr spectroscopy experiments as: carbohydrate sequence [see text]. | 2000 | 10795814 |
| response to xanthomonas campestris pv. vesicatoria in tomato involves regulation of ethylene receptor gene expression. | although ethylene regulates a wide range of defense-related genes, its role in plant defense varies greatly among different plant-microbe interactions. we compared ethylene's role in plant response to virulent and avirulent strains of xanthomonas campestris pv. vesicatoria in tomato (lycopersicon esculentum mill.). the ethylene-insensitive never ripe (nr) mutant displays increased tolerance to the virulent strain, while maintaining resistance to the avirulent strain. expression of the ethylene r ... | 2000 | 10806227 |
| cloning and expression of ntnd, encoding a novel nad(p)(+)-independent 4-nitrobenzyl alcohol dehydrogenase from pseudomonas sp. strain tw3. | pseudomonas sp. strain tw3 is able to metabolize 4-nitrotoluene to 4-nitrobenzoate and toluene to benzoate aerobically via a route analogous to the upper pathway of the tol plasmids. we report the cloning and characterization of a benzyl alcohol dehydrogenase gene (ntnd) which encodes the enzyme for the catabolism of 4-nitrobenzyl alcohol and benzyl alcohol to 4-nitrobenzaldehyde and benzaldehyde, respectively. the gene is located downstream of the previously reported ntn gene cluster. ntnd bear ... | 2000 | 10809692 |
| prey range characterization, ribotyping, and diversity of soil and rhizosphere bdellovibrio spp. isolated on phytopathogenic bacteria. | thirty new bdellovibrio strains were isolated from an agricultural soil and from the rhizosphere of plants grown in that soil. using a combined molecular and culture-based approach, we found that the soil bdellovibrios included subpopulations of organisms that differed from rhizosphere bdellovibrios. thirteen soil and seven common bean rhizosphere bdellovibrio strains were isolated when pseudomonas corrugata was used as prey; seven and two soil strains were isolated when erwinia carotovora subsp ... | 2000 | 10831412 |
| the exbd2 gene as well as the iron-uptake genes tonb, exbb and exbd1 of xanthomonas campestris pv. campestris are essential for the induction of a hypersensitive response on pepper (capsicum annuum). | the tonb, exbb and exbd1 genes of xanthomonas campestris pv. campestris are essential for ferric iron uptake. in contrast, the exbd2 gene located in the same gene cluster is not essential. mutational analysis revealed that the ferric-iron-uptake genes tonb, exbb and exbd1 are necessary for the induction of a hypersensitive response (hr) on the nonhost plant pepper (capsicum annuum) and the induction of typical black rot symptoms on the host plant cauliflower (brassica oleracea). again, the exbd2 ... | 2000 | 10832632 |
| identification of sinorhizobium meliloti genes regulated during symbiosis. | rna fingerprinting by arbitrarily primed pcr was used to isolate sinorhizobium meliloti genes regulated during the symbiotic interaction with alfalfa (medicago sativa). sixteen partial cdnas were isolated whose corresponding genes were differentially expressed between symbiotic and free-living conditions. thirteen sequences corresponded to genes up-regulated during symbiosis, whereas three were instead repressed during establishment of the symbiotic interaction. seven cdnas corresponded to known ... | 2000 | 10850975 |
| role of the dpr product in oxygen tolerance in streptococcus mutans. | we have previously identified and characterized the alkyl hydroperoxide reductase of streptococcus mutans, which consists of two components, nox-1 and ahpc. deletion of both nox-1 and ahpc had no effect on the sensitivity of s. mutans to cumene hydroperoxide or h(2)o(2), implying that the existence of another antioxidant system(s) independent of the nox-1-ahpc system compensates for the deficiency. here, a new antioxidant gene (dpr for dps-like peroxide resistance gene) was isolated from the s. ... | 2000 | 10850989 |
| marinomonas mediterranea mmb-1 transposon mutagenesis: isolation of a multipotent polyphenol oxidase mutant. | marinomonas mediterranea is a melanogenic marine bacterium expressing a multifunctional polyphenol oxidase (ppo) able to oxidize substrates characteristic for laccases and tyrosinases, as well as produce a classical tyrosinase. a new and quick method has been developed for screening laccase activity in culture plates to detect mutants differentially affected in this ppo activity. transposon mutagenesis has been applied for the first time to m. mediterranea by using different minitransposons load ... | 2000 | 10850991 |
| mutations in oxyr resulting in peroxide resistance in xanthomonas campestris. | a spontaneous xanthomonas campestris pv. phaseoli h(2)o(2)-resistant mutant emerged upon selection with 1 mm h(2)o(2). in this report, we show that growth of this mutant under noninducing conditions gave high levels of catalase, alkyl hydroperoxide reductase (ahpc and ahpf), and oxyr. the h(2)o(2) resistance phenotype was abolished in oxyr-minus derivatives of the mutant, suggesting that elevated levels and mutations in oxyr were responsible for the phenotype. nucleotide sequence analysis of the ... | 2000 | 10851004 |
| virulence of the phytopathogen pseudomonas syringae pv. maculicola is rpon dependent. | we cloned the rpon (ntra and glnf) gene encoding sigma(54) from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. the p. syringae es4326 rpon gene complemented pseudomonas aeruginosa, escherichia coli, and klebsiella aerogenes rpon mutants for a variety of rpon mutant phenotypes, including the inability to utilize nitrate as sole nitrogen source. dna sequence analysis of the p. syringae es4326 rpon gene revealed that the deduced amino acid sequence was most similar (86% identi ... | 2000 | 10852883 |
| the alternative sigma factor rpon is required for hrp activity in pseudomonas syringae pv. maculicola and acts at the level of hrpl transcription. | beta-glucuronidase (uida) reporter gene fusions were constructed for the hrpz, hrpl, and hrps genes from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. these reporters, as well as an avrrpt2-uida fusion, were used to measure transcriptional activity in es4326 and a es4326 rpon mutant. rpon was required for the expression of avrrpt2, hrpz, and hrpl in vitro in minimal media and in vivo when infiltrated into arabidopsis thaliana leaves. in contrast, the expression of hrps was ... | 2000 | 10852884 |
| importance of holotoxin assembly in ptl-mediated secretion of pertussis toxin from bordetella pertussis. | we examined the structural components of pertussis toxin that are required for efficient export from bordetella pertussis via the ptl system, a member of the type iv family of macromolecular transporters. first, we constructed a strain of b. pertussis that contains a functional ptl system but does not produce pertussis toxin. plasmids which express either the s1 subunit or the b oligomer were then introduced into this strain. we found that the b oligomer of the toxin is not secreted in the absen ... | 2000 | 10858221 |
| influence of deletions within domain ii of exotoxin a on its extracellular secretion from pseudomonas aeruginosa. | pseudomonas aeruginosa is a gram-negative bacterium that secretes many proteins into the extracellular medium via the xcp machinery. this pathway, conserved in gram-negative bacteria, is called the type ii pathway. the exoproteins contain information in their amino acid sequence to allow targeting to their secretion machinery. this information may be present within a conformational motif. the nature of this signal has been examined for p. aeruginosa exotoxin a (pe). previous studies failed to id ... | 2000 | 10869085 |
| bioaugmentation of activated sludge by an indigenous 3-chloroaniline-degrading comamonas testosteroni strain, i2gfp. | a strain identified as comamonas testosteroni i2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-ca). during the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. this strain was tested for its ability to clean wastewater containing 3-ca upon inoculation into activated sludge. to monitor its survival, the strain was chromosomally marked with the gfp gene and designated i2gfp. after inoculatio ... | 2000 | 10877785 |
| molecular analysis of surfactant-driven microbial population shifts in hydrocarbon-contaminated soil. | we analyzed the impact of surfactant addition on hydrocarbon mineralization kinetics and the associated population shifts of hydrocarbon-degrading microorganisms in soil. a mixture of radiolabeled hexadecane and phenanthrene was added to batch soil vessels. witconol sn70 (a nonionic, alcohol ethoxylate) was added in concentrations that bracketed the critical micelle concentration (cmc) in soil (cmc') (determined to be 13 mg g(-1)). addition of the surfactant at a concentration below the cmc' (2 ... | 2000 | 10877792 |
| variation among strains of xanthomonas campestris pv. vasculorum from mauritius and other countries based on fatty acid analysis. | fatty acid profiling was used to study variation amongst strains of xanthomonas campestris pv. vasculorum (xcv). they could be divided into five groups using cellular fatty acid profiles. group a strains represent a new and little known taxon and all came from plants of broom bamboo (thysanolaena maxima) from mauritius. group b strains included the xcv pathotype reference strain and were from palms, broom bamboo and sugarcane from mauritius, reunion and australia. group c contained southern afri ... | 2000 | 10879989 |
| cultivar-specific avirulence and virulence functions assigned to avrpphf in pseudomonas syringae pv. phaseolicola, the cause of bean halo-blight disease. | the avrpphf gene was cloned from pseudomonas syringae pathovar phaseolicola (pph:) races 5 and 7, based on its ability to confer avirulence towards bean cultivars carrying the r1 gene for halo-blight resistance, such as red mexican. avrpphf comprised two open reading frames, which were both required for function, and was located on a 154 kb plasmid (pav511) in pph: strain rw60 of pph:, lacking pav511, displayed a loss in virulence to a range of previously susceptible cultivars such as tendergree ... | 2000 | 10880434 |
| [major-polygene effect analysis of resistance to bacterial blight (xanthomonas campestris pv. oryzae) in rice]. | five crosses between resistance and susceptible were analyzed to study major-polygene effect using major-polygene mixed mode. the result showed that 3 of 5 crosses were controlled by both major gene and polygene. in addition, there were large variation of additive effect, variance as well as heredity of major gene polygene in 3 crosses. major gene was predominant in resistant variation, but durability should be considered. we suggested that construct major-polygene system be constructed in the l ... | 2000 | 10883537 |
| enhancement of induced disease resistance by simultaneous activation of salicylate- and jasmonate-dependent defense pathways in arabidopsis thaliana. | the plant-signaling molecules salicylic acid (sa) and jasmonic acid (ja) play an important role in induced disease resistance pathways. cross-talk between sa- and ja-dependent pathways can result in inhibition of ja-mediated defense responses. we investigated possible antagonistic interactions between the sa-dependent systemic acquired resistance (sar) pathway, which is induced upon pathogen infection, and the ja-dependent induced systemic resistance (isr) pathway, which is triggered by nonpatho ... | 2000 | 10890883 |
| sequence and molecular analysis of the rpoa cluster genes from xanthomonas campestris pv. campestris. | the xanthomonas campestris rpsm (s13)-rpsk (s11)-rpsd (s4)-rpoa (alpha)-rplq (l17) cluster, encoding rna polymerase alpha-subunit and four ribosomal proteins, reside in a 3164-bp dna region. the n-terminal sequence of the authentic alpha-protein determined chemically matches that predicted from the nucleotide sequence. rplq is monocistronic, instead of being co-transcribed with the other genes as in escherichia coli. antiserum against the his-tagged alpha-protein cross-reacted with the e. coli a ... | 2000 | 10899600 |
| requirement of the pseudomonas aeruginosa tonb gene for high-affinity iron acquisition and infection. | to investigate the contribution of the tonb protein to high-affinity iron acquisition in pseudomonas aeruginosa, we constructed tonb-inactivated mutants from strain pao1 and its derivative deficient in producing the siderophores pyoverdin and pyochelin. the tonb mutants could not grow in a free-iron-restricted medium prepared by apotransferrin addition, even though the medium was supplemented with each purified siderophore or with a heme source (hemoglobin or hemin). the tonb inactivation was sh ... | 2000 | 10899848 |
| role of phosphoglucomutase of bordetella bronchiseptica in lipopolysaccharide biosynthesis and virulence. | the phosphoglucomutase (pgm)-encoding gene of bordetella bronchiseptica is required for lipopolysaccharide (lps) biosynthesis. an insertion mutant of the wild-type b. bronchiseptica strain bb7865 which disrupted lps biosynthesis was created and characterized (bb7865pgm). genetic analysis of the mutated gene showed it shares high identity with pgm genes of various bacterial species and forms part of an operon which also encompasses the gene encoding phosphoglucose isomerase. functional assays for ... | 2000 | 10899872 |
| a protease-resistant catalase, kata, released upon cell lysis during stationary phase is essential for aerobic survival of a pseudomonas aeruginosa oxyr mutant at low cell densities. | a pseudomonas aeruginosa oxyr mutant was dramatically sensitive to h(2)o(2), despite possessing wild-type catalase activity. oxygen-dependent oxyr phenotypes also included an inability to survive aerobic serial dilution in luria broth and to resist aminoglycosides. plating the oxyr mutant after serial dilution in its own spent culture supernatant, which contained the major catalase kata, or under anaerobic conditions allowed for survival. kata was resistant to sodium dodecyl sulfate, proteinase ... | 2000 | 10913089 |
| novel insertion sequence elements associated with genetic heterogeneity and phenotype conversion in ralstonia solanacearum. | three insertion sequences (is) elements were isolated from the phytopathogen ralstonia solanacearum. southern hybridization using these is elements as probes revealed hybridization profiles that varied greatly between different strains of the pathogen. during a spontaneous phenotype conversion event, the promoter of the phca gene was interrupted by one of these is elements. | 2000 | 10913109 |
| effect of field inoculation with sinorhizobium meliloti l33 on the composition of bacterial communities in rhizospheres of a target plant (medicago sativa) and a non-target plant (chenopodium album)-linking of 16s rrna gene-based single-strand conformation polymorphism community profiles to the diversity of cultivated bacteria. | fourteen weeks after field release of luciferase gene-tagged sinorhizobium meliloti l33 in field plots seeded with medicago sativa, we found that the inoculant also occurred in bulk soil from noninoculated control plots. in rhizospheres of m. sativa plants, s. meliloti l33 could be detected in noninoculated plots 12 weeks after inoculation, indicating that growth in the rhizosphere preceded spread into bulk soil. to determine whether inoculation affected bacterial diversity, 1,119 bacteria were ... | 2000 | 10919821 |
| pseudomonas syringae hrp type iii secretion system and effector proteins. | pseudomonas syringae is a member of an important group of gram-negative bacterial pathogens of plants and animals that depend on a type iii secretion system to inject virulence effector proteins into host cells. in p. syringae, hrp/hrc genes encode the hrp (type iii secretion) system, and avirulence (avr) and hrp-dependent outer protein (hop) genes encode effector proteins. the hrp/hrc genes of p. syringae pv syringae 61, p. syringae pv syringae b728a, and p. syringae pv tomato dc3000 are flanke ... | 2000 | 10922033 |
| molecular and cell biology aspects of plague. | a 70-kb virulence plasmid (sometimes called pyv) enables yersinia spp. to survive and multiply in the lymphoid tissues of their host. it encodes the yop virulon, a system consisting of secreted proteins called yops and their dedicated type iii secretion apparatus called ysc. the ysc apparatus forms a channel composed of 29 proteins. of these, 10 have counterparts in almost every type iii system. secretion of some yops requires the assistance, in the bacterial cytosol, of small individual chapero ... | 2000 | 10922034 |
| parameters affecting gene expression from the pm promoter in gram-negative bacteria. | the pm promoter inserted chromosomally or in broad-host-range replicons based on plasmid rsf1010 or rk2 are useful systems for both high- and low-level expression of cloned genes in several gram-negative bacterial species. the positive pm regulator xyls is activated by certain substituted benzoic acid derivatives, and here we show that these effectors induce expression of pm at similar relative ranking levels in both escherichia coli and pseudomonas aeruginosa however, the kinetics of expression ... | 2000 | 10935724 |
| genomic and phenotypic characterization of xanthomonas cynarae sp. nov., a new species that causes bacterial bract spot of artichoke (cynara scolymus l.). | a bacterial disease of artichoke (cynara scolymus l.) was first observed in 1954 in brittany and the loire valley, france. this disease causes water-soaked spots on bracts and depreciates marketability of the harvest. ten strains of the pathogen causing bacterial spot of artichoke, previously identified as a member of the genus xanthomonas, were characterized and compared with type and pathotype strains of the 20 xanthomonas species using a polyphasic study including both phenotypic and genomic ... | 2000 | 10939652 |
| stationary-phase variation due to transposition of novel insertion elements in xanthomonas oryzae pv. oryzae. | xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. spontaneous mutants which are deficient for virulence and extracellular polysaccharide (eps) production accumulate in large numbers in stationary-phase cultures of this bacterium, a phenomenon which we have called stationary-phase variation. a clone (psd1) carrying the eps biosynthetic gene (gum) cluster of x. oryzae pv. oryzae restored eps production and virulence to several spv (for stationary-phase variatio ... | 2000 | 10940020 |
| from rags to riches: insights from the first genomic sequence of a plant pathogenic bacterium. | the recently published genomic sequence of xylella fastidiosa is the first for a free-living plant pathogen and provides clues to mechanisms of pathogenesis and survival in insect vectors. the sequence data should lead to improved control of this pathogen. | 2000 | 11178244 |
| hbar, a 4-hydroxybenzoate sensor and fnr-crp superfamily member, regulates anaerobic 4-hydroxybenzoate degradation by rhodopseudomonas palustris. | under anaerobic conditions, structurally diverse aromatic compounds are catabolized by bacteria to form benzoyl-coenzyme a (benzoyl-coa), the starting compound for a central reductive pathway for aromatic ring degradation. the structural genes required for the conversion of 4-hydroxybenzoate (4-hba) to benzoyl-coa by rhodopseudomonas palustris have been identified. here we describe a regulatory gene, hbar, that is part of the 4-hba degradation gene cluster. an hbar mutant that was constructed wa ... | 2000 | 10613868 |
| role of leaf surface sugars in colonization of plants by bacterial epiphytes. | the relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of pseudomonas fluorescens on individual bean leaves. data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. sugars were depleted during the course of bacterial coloni ... | 2000 | 10618250 |
| mechanism of oxygen availability from hydrogen peroxide to aerobic cultures of xanthomonas campestris. | fundamental studies on the availability of oxygen from the decomposition of h(2)o(2), in vivo, by xanthomonas campestris, when h(2)o(2) is used as an oxygen source are presented. it was found that the h(2)o(2) added extracellularly (0.1-6 mm) was decomposed intracellularly. further, when h(2)o(2) was added, the flux of h(2)o(2) into the cell, is regulated by the cell. the steady-state h(2)o(2) flux into the cell was estimated to be 9.7 x 10(-8) mol m(-2) s(-1). in addition, it was proved that th ... | 2000 | 10620764 |
| bacterial primary colonization and early succession on surfaces in marine waters as determined by amplified rrna gene restriction analysis and sequence analysis of 16s rrna genes. | the nearly universal colonization of surfaces in marine waters by bacteria and the formation of biofilms and biofouling communities have important implications for ecological function and industrial processes. however, the dynamics of surface attachment and colonization in situ, particularly during the early stages of biofilm establishment, are not well understood. experimental surfaces that differed in their degrees of hydrophilicity or hydrophobicity were incubated in a salt marsh estuary tida ... | 2000 | 10653705 |
| isolation, partial sequencing, and expression of pathogenesis-related cdna genes from pepper leaves infected by xanthomonas campestris pv. vesicatoria. | specific cdnas showing differential expression in bacteria-infected pepper leaves as opposed to healthy leaves were isolated from a pepper cdna library from hypersensitive response (hr) lesions of leaves infected with an avirulent strain of xanthomonas campestris pv. vesicatoria. among a total of 282 cdna clones tested, 36 individual cdna genes (13%) hybridized strongly or differentially to the cdna probes from bacteria-infected leaves. ten capsicum annuum-induced (cai) genes encoding putative t ... | 2000 | 10656596 |
| cdna-aflp analysis of differential gene expression in the prokaryotic plant pathogen erwinia carotovora. | for studies of differential gene expression in prokaryotes, methods for synthesizing representative cdna populations are required. here, a technique is described for the synthesis of cdna from the potato pathogens erwinia carotovora subsp. atroseptica (eca) and erwinia carotovora subsp. carotovora (ecc) using a combination of short oligonucleotide (11-mer) primers that were known to anneal to conserved sequences in the 3' regions of enterobacterial genes. specific pcr amplifications with primers ... | 2000 | 10658663 |
| effects of calcium and calcium chelators on growth and morphology of escherichia coli l-form nc-7. | growth of a wall-less, l-form of escherichia coli specifically requires calcium, and in its absence, cells ceased dividing, became spherical, swelled, developed large vacuoles, and eventually lysed. the key cell division protein, ftsz, was present in the l-form at a concentration five times less than that in the parental strain. one interpretation of these results is that the l-form possesses an enzoskeleton partly regulated by calcium. | 2000 | 10671467 |
| expression analysis and characterization of the mutant of a growth-phase- and starvation-regulated monofunctional catalase gene from xanthomonas campestris pv. phaseoli. | analysis of the xanthomonas campestris pv. phaseoli (xp) catalase profile using an activity gel revealed at least two distinct monofunctional catalase isozymes denoted kat1 and kat2. kat1 was expressed throughout growth, whereas kat2 was expressed only during the stationary phase of growth. the nucleotide sequence of a previously isolated monofunctional catalase gene, xp kate, was determined. the deduced amino acid sequence of xp kate showed a high percentage identity to an atypical group of mon ... | 2000 | 10675038 |
| nitric oxide modulates the activity of tobacco aconitase. | recent evidence suggests an important role for nitric oxide (no) signaling in plant-pathogen interactions. additional elucidation of the role of no in plants will require identification of no targets. since aconitases are major no targets in animals, we examined the effect of no on tobacco (nicotiana tabacum) aconitase. the tobacco aconitases, like their animal counterparts, were inhibited by no donors. the cytosolic aconitase in animals, in addition to being a key redox and no sensor, is conver ... | 2000 | 10677450 |
| actinobacillus pleuropneumoniae iron transport: a set of exbbd genes is transcriptionally linked to the tbpb gene and required for utilization of transferrin-bound iron. | upon iron restriction, actinobacillus pleuropneumoniae has been shown to express the transferrin-binding proteins tbpb and tbpa, both of which have been implied to be important virulence factors. in order to identify additional iron-regulated proteins, we cloned and analyzed the region upstream of the transferrin-binding protein genes in an a. pleuropneumoniae serotype 7 strain. we located immediately upstream of the tbpb gene two open reading frames which were 43% homologous to the neisserial e ... | 2000 | 10678921 |
| identification of a lexa gene in, and construction of a lexa mutant of, xanthomonas campestris pv. citri. | the lexa gene of xanthomonas campestris pathovar citri (x.c. pv. citri) was cloned and sequenced. the 639-bp open reading frame encodes a protein of 213 amino acids that shares substantial sequence homology with the products of previously characterized lexa genes, sharing 46% identity with the lexa protein of escherichia coli. amino acids required for autocatalytic cleavage of lexa are conserved in the x.c. pv. citri protein, whereas domains thought to mediate dna binding differ markedly from th ... | 2000 | 10688691 |
| association of the cytoplasmic membrane protein xpsn with the outer membrane protein xpsd in the type ii protein secretion apparatus of xanthomonas campestris pv. campestris. | an xps gene cluster composed of 11 open reading frames is required for the type ii protein secretion in xanthomonas campestris pv. campestris. immediately upstream of the xpsd gene, which encodes an outer membrane protein that serves as the secretion channel by forming multimers, there exists an open reading frame (previously designated orf2) that could encode a protein of 261 amino acid residues. its n-terminal hydrophobic region is a likely membrane-anchoring sequence. antibody raised against ... | 2000 | 10692359 |
| succession of microbial communities during hot composting as detected by pcr-single-strand-conformation polymorphism-based genetic profiles of small-subunit rrna genes. | a cultivation-independent technique for genetic profiling of pcr-amplified small-subunit rrna genes (ssu rdna) was chosen to characterize the diversity and succession of microbial communities during composting of an organic agricultural substrate. pcr amplifications were performed with dna directly extracted from compost samples and with primers targeting either (i) the v4-v5 region of eubacterial 16s rrna genes, (ii) the v3 region in the 16s rrna genes of actinomycetes, or (iii) the v8-v9 regio ... | 2000 | 10698754 |
| survival and epiphytic fitness of a nonpathogenic mutant of xanthomonas campestris pv. glycines. | xanthomonas campestris pv. glycines is the causal agent of bacterial pustule disease of soybeans. the objective of this work was to construct a nonpathogenic mutant derived from the pathogenic wild-type strain yr32 and to evaluate its effectiveness in preventing growth of its parent on the soybean phyllosphere. a mini-tn5-derived transposon was used to generate nonpathogenic mutants. southern hybridization and pulsed-field gel electrophoresis confirmed the presence of a single transposon in each ... | 2000 | 10698789 |
| microbial relatives of the seed storage proteins of higher plants: conservation of structure and diversification of function during evolution of the cupin superfamily. | this review summarizes the recent discovery of the cupin superfamily (from the latin term "cupa," a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic beta-barrel core, led to the identification of a small number of conserved residues a ... | 2000 | 10704478 |
| use of 16s rdna sequences as signature characters to identify xylella fastidiosa. | the nucleotide sequences of 16s rdnas (coding for the small subunit ribosomal rnas) were used to identify xylella fastidiosa, a nutritionally fastidious plant pathogenic bacterium. the near-complete 16s rdnas from nine strains of xyl. fastidiosa, including seven pathotypes and one strain of xanthomonas campestris pv. campestris, were amplified through pcr with two conserved primers (forward primer 5'-aga gtt tga tcc tgg ctc ag-3' and reverse primer 5'-aag gag gtg atc cag cc-3') and sequenced. th ... | 2000 | 10568800 |
| molecular characterization and expression of the recx gene of xanthomonas campestris pv. citri. | two genes important in dna repair, reca and lexa, were recently identified in xanthomonas campestris pathovar citri (x.c. pv. citri). an open reading frame located immediately downstream of lexa and reca has now been isolated from this pathovar and characterized. this 486-bp open reading frame encodes a protein of 162 amino acids and shares substantial sequence similarity with recx of other bacterial species. the x.c. pv. citri recx protein was overexpressed in escherichia coli and purified; sds ... | 2001 | 11178726 |
| ethylene-dependent salicylic acid regulates an expanded cell death response to a plant pathogen. | the molecular events associated with susceptible plant responses to disease-causing organisms are not well understood. we have previously shown that ethylene-insensitive tomato plants infected with xanthomonas campestris pv. vesicatoria have greatly reduced disease symptoms relative to wild-type cultivars. here we show that salicylic acid (sa) is also an important component of the susceptible disease response. sa accumulates in infected wild-type tissues and is correlated with necrosis but does ... | 2001 | 11208023 |
| exchange of xcp (gsp) secretion machineries between pseudomonas aeruginosa and pseudomonas alcaligenes: species specificity unrelated to substrate recognition. | pseudomonas aeruginosa and pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type ii or general secretory pathway, which requires at least 12 xcp gene products (xcpa and xcpp to -z). despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. based on results obtained with erwinia, it has been proposed that the xcpp and/or xcpq homologs determine this secretion specificity (m. linderberg, g. ... | 2001 | 11208795 |
| the evolutionary history of chromosomal super-integrons provides an ancestry for multiresistant integrons. | integrons are genetic elements that acquire and exchange exogenous dna, known as gene cassettes, by a site-specific recombination mechanism. characterized gene cassettes consist of a target recombination sequence (attc site) usually associated with a single open reading frame coding for an antibiotic resistance determinant. the affiliation of multiresistant integrons (mris), which contain various combinations of antibiotic resistance gene cassettes, with transferable elements underlies the rapid ... | 2001 | 11209061 |
| structures of the o4 and o18 antigens of stenotrophomonas maltophilia: a case of enantiomeric repeating units. | the o-specific side-chain polymers of lipopolysaccharides from the reference strains for stenotrophomonas maltophilia serogroups 04 and o18 are both xylosylated rhamnans. in the 04 polymer, both sugar components are the d isomers, whereas the o18 polymer contains only the l isomers. by means of nmr spectroscopy, methylation analysis and smith degradation, the repeating unit of the 04 polymer was identified as a doubly-branched pentasaccharide of the structure shown below. the o18 polymer is base ... | 2001 | 11217974 |
| biological sensor for sucrose availability: relative sensitivities of various reporter genes. | a set of three sucrose-regulated transcriptional fusions was constructed. fusions p61rytir, p61rylac, and p61ryice contain the scrr sucrose repressor gene and the promoterless gfp, lacz, and inaz reporter genes, respectively, fused to the scry promoter from salmonella enterica serovar typhimurium. cells of erwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. while a large variation in sucrose-dependent reporter gene activity was observe ... | 2001 | 11229926 |
| salmonella host cell invasion emerged by acquisition of a mosaic of separate genetic elements, including salmonella pathogenicity island 1 (spi1), spi5, and sope2. | salmonella spp. possess a conserved type iii secretion system encoded within the pathogenicity island 1 (spi1; centisome 63), which mediates translocation of effector proteins into the host cell cytosol to trigger responses such as bacterial internalization. several translocated effector proteins are encoded in other regions of the salmonella chromosome. it remains unclear how this complex chromosomal arrangement of genes for the type iii apparatus and the effector proteins emerged and how the d ... | 2001 | 11244077 |
| complete dna sequence and comparative analysis of the 50-kilobase virulence plasmid of salmonella enterica serovar choleraesuis. | the complete nucleotide sequence of pkdsc50, a large virulence plasmid from salmonella enterica serovar choleraesuis strain rf-1, has been determined. we identified 48 of the open reading frames (orfs) encoded by the 49,503-bp molecule. pkdsc50 encodes a known virulence-associated operon, the spv operon, which is composed of genes essential for systemic infection by nontyphoidal salmonella. analysis of the genetic organization of pkdsc50 suggests that the plasmid is composed of several virulence ... | 2001 | 11254626 |
| an inner membrane platform in the type ii secretion machinery of gram-negative bacteria. | the type ii secretion machinery allows most gram-negative bacteria to deliver virulence factors into their surroundings. we report that in erwinia chrysanthemi, gspe (the putative ntpase), gspf, gspl and gspm constitute a complex in the inner membrane that is presumably used as a platform for assembling other parts of the secretion machinery. the gspe-gspf-gspl-gspm complex was demonstrated by two methods: (i) co-immunoprecipitation of gspe-gspf-gspl with antibodies raised against either gspe or ... | 2001 | 11266368 |
| hydrogen peroxide-forming nadh oxidase belonging to the peroxiredoxin oxidoreductase family: existence and physiological role in bacteria. | amphibacillus xylanus and sporolactobacillus inulinus nadh oxidases belonging to the peroxiredoxin oxidoreductase family show extremely high peroxide reductase activity for hydrogen peroxide and alkyl hydroperoxides in the presence of the small disulfide redox protein, ahpc (peroxiredoxin). in order to investigate the distribution of this enzyme system in bacteria, 15 bacterial strains were selected from typical aerobic, facultatively anaerobic, and anaerobic bacteria. ahpc-linked alkyl hydroper ... | 2001 | 11274101 |
| complete dna sequence and analysis of the large virulence plasmid of shigella flexneri. | the complete sequence analysis of the 210-kb shigella flexneri 5a virulence plasmid was determined. shigella spp. cause dysentery and diarrhea by invasion and spread through the colonic mucosa. most of the known shigella virulence determinants are encoded on a large plasmid that is unique to virulent strains of shigella and enteroinvasive escherichia coli; these known genes account for approximately 30 to 35% of the virulence plasmid. in the complete sequence of the virulence plasmid, 286 open r ... | 2001 | 11292750 |
| study of the role of antimicrobial glucosinolate-derived isothiocyanates in resistance of arabidopsis to microbial pathogens. | crude aqueous extracts from arabidopsis leaves were subjected to chromatographic separations, after which the different fractions were monitored for antimicrobial activity using the fungus neurospora crassa as a test organism. two major fractions were obtained that appeared to have the same abundance in leaves from untreated plants versus leaves from plants challenge inoculated with the fungus alternaria brassicicola. one of both major antimicrobial fractions was purified to homogeneity and iden ... | 2001 | 11299350 |
| evidence for the involvement of an oxidative stress in the initiation of infection of pear by erwinia amylovora. | involvement of an oxidative burst, usually related to incompatible plant/pathogen interactions leading to hypersensitive reactions, was investigated with erwinia amylovora, the causal agent of fire blight of maloideae subfamily of rosaceae, in interaction with pear (pyrus communis; compatible situation) and tobacco (nicotiana tabacum; incompatible situation). as expected, this necrogenic bacterium induced in tobacco a sustained production of superoxide anion, lipid peroxidation, electrolyte leak ... | 2001 | 11299395 |
| effects of urate, a natural inhibitor of peroxynitrite-mediated toxicity, in the response of arabidopsis thaliana to the bacterial pathogen pseudomonas syringae. | urate, a natural peroxynitrite scavenger, has been used to investigate the possible role of peroxynitrite during plant-pathogen interactions. urate greatly reduced lesion formation in arabidopsis leaves treated with an abiotic peroxynitrite-generating system or with a peroxynitrite solution, indicating that it can act as an effective scavenger in planta. in the interaction with the avirulent pseudomonas syringae pv. phaseolicola (avrrpm1+), cell death in the inoculated area was strongly reduced ... | 2001 | 11309143 |
| reduced expression of the tomato ethylene receptor gene leetr4 enhances the hypersensitive response to xanthomonas campestris pv. vesicatoria. | the hypersensitive response (hr) involves rapid death of cells at the site of pathogen infection and is thought to limit pathogen growth through the plant. ethylene regulates senescence and developmental programmed cell death, but its role in hypersensitive cell death is less clear. expression of two ethylene receptor genes, nr and leetr4, is induced in tomato (lycopersicon esculentum cv. mill) leaves during an hr to xanthomonas campestris pv. vesicatoria, with the greatest increase observed in ... | 2001 | 11310736 |
| stable transformation of the xylella fastidiosa citrus variegated chlorosis strain with oric plasmids. | xylella fastidiosa is a gram-negative, xylem-limited bacterium affecting economically important crops (e.g., grapevine, citrus, and coffee). the citrus variegated chlorosis (cvc) strain of x. fastidiosa is the causal agent of this severe disease of citrus in brazil and represents the first plant-pathogenic bacterium for which the genome sequence was determined. plasmids for the cvc strain of x. fastidiosa were constructed by combining the chromosomal replication origin (oric) of x. fastidiosa wi ... | 2001 | 11319110 |
| identification and characterization of a developmentally regulated protein, esha, required for sporogenic hyphal branches in streptomyces griseus. | to identify sporulation-specific proteins that might serve as targets of developmental regulatory factors in streptomyces, we examined total proteins of streptomyces griseus by two-dimensional gel electrophoresis. among five proteins that were present at high levels during sporulation but absent from vegetative cells, two of the proteins, p3 and p4, were absent from developmental mutants that undergo aberrant morphogenesis. the deduced amino acid sequence of the gene that encodes p3 (esha) showe ... | 2001 | 11325927 |
| roles of aconitase in growth, metabolism, and morphological differentiation of streptomyces coelicolor. | the studies of aconitase presented here, along with those of citrate synthase (p. h. viollier, w. minas, g. e. dale, m. folcher, and c. j. thompson, j. bacteriol. 183:3184-3192, 2001), were undertaken to investigate the role of the tricarboxylic acid (tca) cycle in streptomyces coelicolor development. a single aconitase activity (acoa) was detected in protein extracts of cultures during column purification. the deduced amino acid sequence of the cloned acoa gene constituted the n-terminal sequen ... | 2001 | 11325949 |
| xanthomonas campestris strain selection for xanthan production from olive mill wastewaters. | four xanthomonas campestris strains were tested in olive mill wastewaters (omw) for xanthan production. differences among strains were found in the range of tolerance to omw concentration and xanthan amount obtained. x. campestris nrrl b-1459 s4lii was chosen by its capability for xanthan production from 50-60% omw as the sole nutrient source. | 2001 | 11329685 |
| genetic mapping and functional analysis of the tomato bs4 locus governing recognition of the xanthomonas campestris pv. vesicatoria avrbs4 protein. | xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper (capsicum spp.) and tomato (lycopersicon spp.). analysis of 17 different lycopersicon accessions with avrbs4-expressing x. campestris pv. vesicatoria strains identified 15 resistant and two susceptible tomato genotypes. genetic analysis revealed that avrbs4 recognition in tomato is governed by a single locus, designated bs4 (bacterial spot resistance locus no. 4). amplified fragment length polymorphism ... | 2001 | 11332727 |
| characterization and mutational analysis of three allelic lsc genes encoding levansucrase in pseudomonas syringae. | in the plant pathogen pseudomonas syringae pv. glycinea pg4180 and other bacterial species, synthesis of the exopolysaccharide levan is catalyzed by the extracellular enzyme levansucrase. the results of southern blotting and pcr analysis indicated the presence of three levansucrase-encoding genes in strain pg4180: lsca, lscb, and lscc. in this study, lscb and lscc were cloned from a genomic library of strain pg4180. sequence analysis of the two lsc genes showed that they were virtually identical ... | 2001 | 11344135 |
| the effect of olive mill wastewaters variability on xanthan production. | xanthan production by xanthomonas campestris from several olive mill wastewaters (omw) was investigated. | 2001 | 11348445 |
| the early stages of filamentous phage philf infection require the host transcription factor, clp. | xanthomonas campestris pv. campestris produces great amounts of an exopolysaccharide (eps), xanthan gum. eight eps loci involved in biosynthesis of the eps were previously located in the chromosome map of strain xc17. in this study, the eps8 region was cloned, sequenced and found to contain a crp homologue whose deduced amino acid sequence possesses similarity to that of the cyclic amp receptor protein of bacteria, with the highest identity (97%) being shared with the x. campestris pv. campestri ... | 2001 | 11361081 |
| structural and functional characterization of the lexa gene of xanthomonas campestris pathovar citri. | the role of the lexa protein and, specifically, its effect on reca expression were analyzed in xanthomonas campestris pathovar citri (x.c. pv. citri). overexpression of lexa from x.c. pv. citri, in the plant pathogen, as well as in escherichia coli, results in increased sensitivity to the dna-damaging agents mitomycin c and ultraviolet radiation, indicating that the recombinant x.c. pv. citri lexa protein is functional in a different bacterial species. immunoblot analysis revealed that the overe ... | 2001 | 11361343 |
| generation of pcr-based dna fragments for specific detection of streptomyces saraceticus n45. | streptomyces saraceticus strain n45, a saprophytic gram-positive bacteria, has been shown to harbor high chitinase activity. due to its potential use in biological control, the cloning of chitinase genes and the development of methods to quickly and precisely detect its presence have become necessary. in this study, pcr-based random amplified polymorphic dna (rapd) and pcr strategies were used to amplify random dna fragments from the genome of s. saraceticus n45. three amplified dna fragments, 4 ... | 2001 | 11370759 |
| the luxm homologue vanm from vibrio anguillarum directs the synthesis of n-(3-hydroxyhexanoyl)homoserine lactone and n-hexanoylhomoserine lactone. | vibrio anguillarum, which causes terminal hemorrhagic septicemia in fish, was previously shown to possess a luxri-type quorum-sensing system (vanri) and to produce n-(3-oxodecanoyl)homoserine lactone (3-oxo-c10-hsl). however, a vani null mutant still activated n-acylhomoserine lactone (ahl) biosensors, indicating the presence of an additional quorum-sensing circuit in v. anguillarum. in this study, we have characterized this second system. using high-pressure liquid chromatography in conjunction ... | 2001 | 11371516 |
| requirement for phosphoglucomutase in exopolysaccharide biosynthesis in glucose- and lactose-utilizing streptococcus thermophilus. | to study the influence of phosphoglucomutase (pgm) activity on exopolysaccharide (eps) synthesis in glucose- and lactose-growing streptococcus thermophilus, a knockout pgm mutant and a strain with elevated pgm activity were constructed. the pgma gene, encoding pgm in s. thermophilus ly03, was identified and cloned. the gene was functional in escherichia coli and was shown to be expressed from its own promoter. the pgma-deficient mutant was unable to grow on glucose, while the mutation did not af ... | 2001 | 11375188 |
| quantitative pcr method for diagnosis of citrus bacterial canker. | for diagnosis of citrus bacterial canker by pcr, an internal standard is employed to ensure the quality of the dna extraction and that proper requisites exist for the amplification reaction. the ratio of pcr products from the internal standard and bacterial target is used to estimate the initial bacterial concentration in citrus tissues with lesions. | 2001 | 11375206 |
| [role of the surface and extracellular substances of the phytopathogenic bacterium xanthomonas campestris in its interactions with cabbage plants]. | changes in some physiological and biochemical characteristics of cabbage (cv. slava) seedling roots in response to inoculation with the phytopathogen xanthomonas campestris and its surface and extracellular substances were evaluated. seven days after the inoculation, the growth of the roots was slightly suppressed and they contained increased amounts of peroxidase. the effect of the lipopolysaccharides stripped from the cell surface or isolated from the culture liquid of x. campestris was simila ... | 2001 | 11386062 |
| expression of the gum operon directing xanthan biosynthesis in xanthomonas campestris and its regulation in planta. | the gum gene cluster of xanthomonas campestris pv. campestris comprises 12 genes whose products are involved in the biosynthesis of the extracellular polysaccharide xanthan. these genes are expressed primarily as an operon from a promoter upstream of the first gene, gumb. although the regulation of xanthan synthesis in vitro has been well studied, nothing is known of its regulation in planta. a reporter plasmid was constructed in which the promoter region of the gum operon was fused to gusa. in ... | 2001 | 11386372 |
| induction of hydroxycinnamoyl-tyramine conjugates in pepper by xanthomonas campestris, a plant defense response activated by hrp gene-dependent and hrp gene-independent mechanisms. | inoculation of pepper leaves, capsicum annuum cv. early calwonder ecw 10r, with strains of xanthomonas campestris led to an accumulation of the phenolic conjugates feruloyltyramine (ft) and p-coumaroyltyramine (ct) 24 h postinoculation in nonhost- and gene-for-gene-determined incompatible interactions with x. campestris pv. campestris and x. campestris pv. vesicatoria, respectively. in contrast, neither compound was detected in compatible interactions with x. campestris pv. vesicatoria. the accu ... | 2001 | 11386374 |
| microbial origin of plant-type 2-keto-3-deoxy-d-arabino-heptulosonate 7-phosphate synthases, exemplified by the chorismate- and tryptophan-regulated enzyme from xanthomonas campestris. | enzymes performing the initial reaction of aromatic amino acid biosynthesis, 2-keto-3-deoxy-d-arabino-heptulosonate 7-phosphate (dahp) synthases, exist as two distinct homology classes. the three classic escherichia coli paralogs are aroa(i) proteins, but many members of the bacteria possess the aroa(ii) class of enzyme, sometimes in combination with aroa(i) proteins. aroa(ii) dahp synthases until now have been shown to be specifically dedicated to secondary metabolism (e.g., formation of ansamy ... | 2001 | 11395471 |
| kinetic analysis of growth and xanthan gum production with xanthomonas campestris on sucrose, using sequentially consumed nitrogen sources. | a batch fermentation strategy using xanthomonas campestris atcc 13951 for xanthan gum production has been established in which all essential medium components are supplied at the onset. this has been achieved using sucrose as sole sugar feedstock. sequential consumption of nitrogen sources (soybean hydrolysates, ammonium and nitrate salts) was observed to facilitate the further optimisation of the medium. biomass accumulation was limited by phosphate availability. xanthan yields of more than 60% ... | 2001 | 11398920 |
| complete dna sequence of yersinia enterocolitica serotype 0:8 low-calcium-response plasmid reveals a new virulence plasmid-associated replicon. | the complete nucleotide sequence and organization of the yersinia enterocolitica serotype 0:8 low-calcium-response (lcr) plasmid, pyve8081, were determined. the 67,720-bp plasmid encoded all the genes known to be part of the lcr stimulon except for ylpa. eight of 13 intact open reading frames of unknown function identified in pyve8081 had homologues in yersinia pestis plasmid pcd1 or in y. enterocolitica serotype 0:9 plasmid pyve227. a region of approximately 17 kbp showed no dna identity to pcd ... | 2001 | 11402007 |
| characterization and expression of beta-1,3-glucanase genes in peach. | beta-1,3-glucanase is one of the pathogenesis-related (pr) proteins involved in plant defense responses. a peach beta-1,3-glucanase gene, designated ppgns1, has been isolated and characterized. the deduced amino acid sequence of the product of ppgns indicates that it is a basic isoform (pi 9.8), and contains a putative signal peptide of 38 amino acids but has no c-terminal extension. amino acid sequence comparisons revealed that ppgns1 is 69% and 67% identical to citrus and soybean beta-1,3-gluc ... | 2001 | 11405630 |
| broad-spectrum antimicrobial activity in vitro of the synthetic peptide d4e1. | broad-spectrum antimicrobial activity of a synthetic peptide, d4e1, is documented in this paper. d4e1 inhibited the growth of several fungal phytopathogens belonging to four classes-ascomycetes, basidiomycetes, deuteromycetes, and oomycetes, and two bacterial pathogens, pseudomonas syringae pv. tabaci and xanthomonas campestris pv. malvacearum race 18. the minimum inhibitory concentration (mic) of d4e1 required to completely inhibit the growth of all fungi studied ranged from 4.67 to 25 microm. ... | 2001 | 11409968 |
| incipient erosion of biostabilized sediments examined using particle-field optical holography. | laser holography allows images of three-dimensional space at ultra-high resolution to be recorded onto photographic plates. recorded scenes can be "replayed" with a second laser beam into free space and optically "interrogated" using either a microscope or a camera by sequentially focusing on increasing distances from the hologram in the field of view (optical sectioning). from these sections, information on the relative locations and orientation in space of suspended particles as well as the mo ... | 2001 | 11414032 |
| ohrr is a repressor of ohra, a key organic hydroperoxide resistance determinant in bacillus subtilis. | bacillus subtilis displays a complex adaptive response to the presence of reactive oxygen species. to date, most proteins that protect against reactive oxygen species are members of the peroxide-inducible perr and sigma(b) regulons. we investigated the function of two b. subtilis homologs of the xanthomonas campestris organic hydroperoxide resistance (ohr) gene. mutational analyses indicate that both ohra and ohrb contribute to organic peroxide resistance in b. subtilis, with the ohra protein pl ... | 2001 | 11418552 |
| influence of acidic exopolysaccharide of xanthomonas campestris ibpm 124 on the kinetic parameters of extracellular bacteriolytic enzymes. | interactions of a negatively charged exopolysaccharide of xanthomonas campestris ibpm 124 with its extracellular enzymes (muramidase, endopeptidase, and neutral phosphatase) and also with egg lysozyme, lysostaphin, muramidase of streptomyces globisporus, and a bacteriolytic enzyme complex of streptomyces albus were studied. all these enzymes were positively charged under the conditions of their maximal activity. it was shown that interaction of the acidic exopolysaccharide from x. campestris wit ... | 2001 | 11421816 |
| bacterial ohr and osmc paralogues define two protein families with distinct functions and patterns of expression. | xanthomonas campestris ohr (a protein involved in organic peroxide protection) and escherichia coli osmc (an osmotically inducible protein of unknown function) are related proteins. database searches and phylogenetic analyses reveal that ohr and osmc homologues cluster into two related subfamilies of proteins widely distributed in both gram-negative and gram-positive bacteria. to determine if these two subfamilies are functionally distinct, ohr and osmc in pseudomonas aeruginosa (a bacterium wit ... | 2001 | 11429455 |