Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| analysis of bacterial lipodepsipeptides by matrix-assisted laser desorption/ionisation time-of-flight and high-performance liquid chromatography with electrospray mass spectrometry. | strains of certain plant pathogenic bacteria, in particular several pathovars of pseudomonas syringae, are known to produce cyclic lipodepsipeptides (ldps) endowed with peculiar structural features and noticeable biological activities. in this study, a mass spectrometry procedure is proposed for screening ldp-producing bacterial strains and for identifying and assessing individual ldps. after matrix-assisted laser desorption/ionisation time-of-flight (maldi-tof) screening of thirteen p. syringae ... | 2001 | 11312513 |
| 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 |
| the cela gene, encoding a glycosyl hydrolase family 3 beta-glucosidase in azospirillum irakense, is required for optimal growth on cellobiosides. | the cela beta-glucosidase of azospirillum irakense, belonging to glycosyl hydrolase family 3 (ghf3), preferentially hydrolyzes cellobiose and releases glucose units from the c(3), c(4), and c(5) oligosaccharides. the growth of a deltacela mutant on these cellobiosides was affected. in a. irakense, the ghf3 beta-glucosidases appear to be functional alternatives for the ghf1 beta-glucosidases in the assimilation of beta-glucosides by other bacteria. | 2001 | 11319128 |
| highly conserved sequences flank avirulence genes: isolation of novel avirulence genes from pseudomonas syringae pv. pisi. | dna sequences flanking two avr genes (avrppia1 and avrppib1) from pseudomonas syringae pv. pisi show a high degree of similarity. specific primers designed from the conserved regions were used in pcr amplifications with all p. syringae pv. pisi races. as well as amplifying the expected avrppia- and avrppib-containing fragments, two additional fragments were amplified: one contained a single open reading frame (orf1) and was found in races of genomic group ii (2, 3a, 4a and 6); the second fragmen ... | 2001 | 11320120 |
| osmoregulated periplasmic glucans of erwinia chrysanthemi. | we report the initial characterization of the osmoregulated periplasmic glucans (opgs) of erwinia chrysanthemi. opgs are intrinsic components of the bacterial envelope necessary to the pathogenicity of this phytopathogenic enterobacterium (f. page, s. altabe, n. hugouvieux-cotte-pattat, j.-m. lacroix, j. robert-baudouy and j.-p. bohin, j. bacteriol. 183:0000-0000, 2001 [companion in this issue]). opgs were isolated by trichloracetic acid treatment and gel permeation chromatography. the synthesis ... | 2001 | 11325941 |
| osmoregulated periplasmic glucan synthesis is required for erwinia chrysanthemi pathogenicity. | erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants. osmoregulated periplasmic glucans (opgs) are intrinsic components of the gram-negative bacterial envelope. we cloned the opggh operon of e. chrysanthemi, encoding proteins involved in the glucose backbone synthesis of opgs, by complementation of the homologous locus mdogh of escherichia coli. opgg and opgh show a high level of similarity with mdog and mdoh, respectively, and mutations in ... | 2001 | 11325942 |
| effects of mutations in the pseudomonas putida miaa gene: regulation of the trpe and trpgdc operons in p. putida by attenuation. | tn5 insertion mutants defective in regulation of the pseudomonas putida trpe and trpgdc operons by tryptophan were found to contain insertions in the p. putida miaa gene, whose product (in escherichia coli) modifies trna(trp) and is required for attenuation. nucleotide sequences upstream of trpe and trpg encode putative leader peptides similar in sequence to leader peptides found in other bacterial species, and the phenotypes of the mutants strongly suggest that transcription of these operons is ... | 2001 | 11325956 |
| tomato ve disease resistance genes encode cell surface-like receptors. | in tomato, ve is implicated in race-specific resistance to infection by verticillium species causing crop disease. characterization of the ve locus involved positional cloning and isolation of two closely linked inverted genes. expression of individual ve genes in susceptible potato plants conferred resistance to an aggressive race 1 isolate of verticillium albo-atrum. the deduced primary structure of ve1 and ve2 included a hydrophobic n-terminal signal peptide, leucine-rich repeats containing 2 ... | 2001 | 11331751 |
| the leucine-rich repeat domain can determine effective interaction between rps2 and other host factors in arabidopsis rps2-mediated disease resistance. | like many other plant disease resistance genes, arabidopsis thaliana rps2 encodes a product with nucleotide-binding site (nbs) and leucine-rich repeat (lrr) domains. this study explored the hypothesized interaction of rps2 with other host factors that may be required for perception of pseudomonas syringae pathogens that express avrrpt2 and/or for the subsequent induction of plant defense responses. crosses between arabidopsis ecotypes col-0 (resistant) and po-1 (susceptible) revealed segregation ... | 2001 | 11333251 |
| overexpression of the tobacco tsi1 gene encoding an erebp/ap2-type transcription factor enhances resistance against pathogen attack and osmotic stress in tobacco. | using mrna differential display analysis, we isolated a salt-induced transcript that showed a significant sequence homology with an erebp/ap2 dna binding motif from oilseed rape plants. with this cdna fragment as a probe, cdna clone tsi1 (for tobacco stress-induced gene1) was isolated from a tobacco cdna library. rna gel blot analysis indicated that transcripts homologous with tsi1 were induced not only in nacl-treated leaves but also in leaves treated with ethephon or salicylic acid. transient ... | 2001 | 11340180 |
| a harpin binding site in tobacco plasma membranes mediates activation of the pathogenesis-related gene hin1 independent of extracellular calcium but dependent on mitogen-activated protein kinase activity. | harpin from the bean halo-blight pathogen pseudomonas syringae pv phaseolicola (harpin(psph)) elicits the hypersensitive response and the accumulation of pathogenesis-related gene transcripts in the nonhost plant tobacco. here, we report the characterization of a nonproteinaceous binding site for harpin(psph) in tobacco plasma membranes, which is assumed to mediate the activation of plant defense responses in a receptor-like manner. binding of 125i-harpin(psph) to tobacco microsomal membranes (d ... | 2001 | 11340183 |
| both the extracellular leucine-rich repeat domain and the kinase activity of fsl2 are required for flagellin binding and signaling in arabidopsis. | in arabidopsis, activation of defense responses by flagellin is triggered by the specific recognition of the most conserved domain of flagellin, represented by the peptide flg22, in a process involving the fls2 gene, which encodes a leucine-rich repeat serine/threonine protein kinase. we show here that the two fls2 mutant alleles, fls2-24 and fls2-17, which were shown previously to confer insensitivity to flg22, also cause impaired flagellin binding. these features are rescued when a functional ... | 2001 | 11340188 |
| structural and functional analysis of the phosphonoacetate hydrolase (phna) gene region in pseudomonas fluorescens 23f. | the pseudomonas fluorescens 23f phosphonoacetate hydrolase gene (phna) encodes a novel carbon-phosphorus bond cleavage enzyme whose expression is independent of the phosphate status of the cell. analysis of the regions adjacent to the phosphonoacetate hydrolase structural gene (phna) indicated the presence of five open reading frames (orfs). these include one (phnr) whose putative product shows high levels of homology to the lysr family of positive transcriptional regulators. its presence was sh ... | 2001 | 11344133 |
| 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 |
| suppression of the ribosomal l2 gene reveals a novel mechanism for stress adaptation in soybean. | pseudomonas syringae pv. glycinea bacteria or zoospores of the fungus phytophthora sojae were used to trigger a hypersensitive reaction (hr) in cell cultures of soybean (glycine max [l.] merr. cv. williams 82). during a screen for genes that show an altered expression as a response to dying neighbour cells we have identified a gene fragment that is specifically but transiently down-regulated in an hr. the corresponding cdna codes for the ribosomal protein l2 (rpl2) of 80s ribosomes, which is ess ... | 2001 | 11346953 |
| development of immunomagnetic separation technique for isolation of pseudomonas syringae pv. phaseolicola. | immunomagnetic separation technique was developed for specific detection and selective isolation of pseudomonas syringae pv. phaseolicola, the agent of halo-blight disease of beans. whole-cell and exopolysaccharide fraction of the bacterium was used for polyclonal antibody production in rabbits. high specificity of the antisera was determined in agglutination reactions. the optimum immunocapture time for both antisera was determined as 1 h by using 1/nl cfu (i.e. 10(6) cfu per ml). no significan ... | 2000 | 11347253 |
| fatty acid ketodienes and fatty acid ketotrienes: michael addition acceptors that accumulate in wounded and diseased arabidopsis leaves. | physical damage and disease are known to lead to changes in the oxylipin signature of plants. we searched for oxylipins produced in response to both wounding and pathogenesis in arabidopsis leaves. linoleic acid 9- and 13-ketodienes (kodes) were found to accumulate in wounded leaves as well as in leaves infected with the pathogen pseudomonas syringae pv. tomato (pst). quantification of the compounds showed that they accumulated to higher levels during the hypersensitive response to pst avrrpm1 t ... | 2000 | 11115128 |
| pathogenesis of the human opportunistic pathogen pseudomonas aeruginosa pa14 in arabidopsis. | the human opportunistic pathogen pseudomonas aeruginosa strain pa14 is a multihost pathogen that can infect arabidopsis. we found that pa14 pathogenesis in arabidopsis involves the following steps: attachment to the leaf surface, congregation of bacteria at and invasion through stomata or wounds, colonization of intercellular spaces, and concomitant disruption of plant cell wall and membrane structures, basipetal movement along the vascular parenchyma, and maceration and rotting of the petiole a ... | 2000 | 11115892 |
| defence gene expression in soybean is linked to the status of the cell death program. | soybean cell cultures (cv. williams 82) respond to pseudomonas syringae bacteria expressing the avirulence gene avra with a hypersensitive reaction, a programmed cell death (pcd) of plant cells to pathogen attack. this pcd is under control of salicylic acid (sa) via an unknown mechanism. in the presence of low concentrations of sa, the cells undergo a very rapid cell death, which needs only half of the time required for the normal hypersensitive reaction (hr). northern blot studies for defence-r ... | 2000 | 11117264 |
| stress induces peroxisome biogenesis genes. | peroxisomes are the cellular location of many antioxidants and are themselves significant producers of reactive oxygen species. in this report we demonstrate the induction of peroxisome biogenesis genes in both plant and animal cells by the universal stress signal molecule hydrogen peroxide. using pex1-luc transgenic plants, rapid local and systemic induction of pex1-luciferase could be demonstrated in vivo in response to physiological levels of hydrogen peroxide. pex1-luciferase was also induce ... | 2000 | 11118212 |
| a phaseolus vulgaris lipoxygenase gene expressed in nodules and in rhizobium tropici inoculated roots. | a genomic clone encoding a common bean lipoxygenase (pvlox5) was isolated from a phaseolus vulgaris library. reverse transcription-polymerase chain reaction analysis revealed that pvlox5 is expressed during nodule development and in rhizobium tropici inoculated roots. there was no detectable expression of pvlox5 in non-inoculated roots, healthy leaves, leaves after pseudomonas syringae pv. tabaci infection, floral buds or dry seeds. | 2000 | 11118627 |
| release of cell-free ice nuclei from halomonas elongata expressing the ice nucleation gene inaz of pseudomonas syringae. | release of ice nuclei in the growth medium of recombinant halomonas elongata cells expressing the inaz gene of pseudomonas syringae was studied in an attempt to produce cell-free active ice nuclei for biotechnological applications. cell-free ice nuclei were not retained by cellulose acetate filters of 0.2 microm pore size. highest activity of cell-free ice nuclei was obtained when cells were grown in low salinity (0.5-5% nacl, w/v). freezing temperature threshold, estimated to be below -7 degree ... | 2000 | 11119152 |
| structure-function analysis of the tobacco mosaic virus resistance gene n. | the tobacco n gene is a member of the toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (tir-nbs-lrr) class of plant resistance (r) genes and confers resistance to tobacco mosaic virus (tmv). we investigated the importance of specific domains of n in inducing tmv resistance, by examining various n deletion and point mutations that introduce single amino acid substitution mutants in vivo. our deletion analysis suggests that the tir, nbs, and lrr domains play an indispensable ... | 2000 | 11121079 |
| simultaneous ethanol and bacterial ice nuclei production from sugar beet molasses by a zymomonas mobilis cp4 mutant expressing the inaz gene of pseudomonas syringae in continuous culture. | the aim of this work was to construct a zymomonas mobilis mutant capable of simultaneous ethanol and ice nuclei production from agricultural by-product such as sugar beet molasses, in steady-state continuous culture. | 2000 | 11123473 |
| oxidative burst and cognate redox signalling reported by luciferase imaging: identification of a signal network that functions independently of ethylene, sa and me-ja but is dependent on mapkk activity. | recognition of avirulent microbial pathogens activates an oxidative burst leading to the accumulation of reactive oxygen intermediates (rois), which are thought to integrate a diverse set of defence mechanisms resulting in the establishment of plant disease resistance. a novel transgenic arabidopsis line containing a gst1:luc transgene was developed and employed to report the temporal and spatial dynamics of roi accumulation and cognate redox signalling in response to attempted infection by avir ... | 2000 | 11123796 |
| membrane-permeabilizing activities of cyclic lipodepsipeptides, syringopeptin 22a and syringomycin e from pseudomonas syringae pv. syringae in human red blood cells and in bilayer lipid membranes. | the pore-forming activities of cyclic lipodepsipeptides (clps), syringopeptin 22a (sp22a) and syringomycin e (sre) were compared on the human red blood cell (rbc) membrane and on bilayer lipid membranes (blms). sp22a above a concentration of 4 x 10(5) molecules/cell significantly increased the rbc membrane permeability for 86rb. with electric current measurements on blm, it was proved that like sre, the sp22a formed two types of ion channels in the membrane, small and large, the latter having si ... | 2000 | 11129239 |
| 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 and localization of nitrilase during symptom development of the clubroot disease in arabidopsis. | the expression of nitrilase in arabidopsis during the development of the clubroot disease caused by the obligate biotroph plasmodiophora brassicae was investigated. a time course study showed that only during the exponential growth phase of the clubs was nitrilase prominently enhanced in infected roots compared with controls. nit1 and nit2 are the nitrilase isoforms predominantly expressed in clubroot tissue, as shown by investigating promoter-beta-glucuronidase fusions of each. two peaks of bet ... | 2000 | 10677430 |
| isolation and characterization of powdery mildew-resistant arabidopsis mutants. | a compatible interaction between a plant and a pathogen is the result of a complex interplay between many factors of both plant and pathogen origin. our objective was to identify host factors involved in this interaction. these factors may include susceptibility factors required for pathogen growth, factors manipulated by the pathogen to inactivate or avoid host defenses, or negative regulators of defense responses. to this end, we identified 20 recessive arabidopsis mutants that do not support ... | 2000 | 10677553 |
| characterization of the foma and fomb gene products from streptomyces wedmorensis, which confer fosfomycin resistance on escherichia coli. | together, the foma and fomb genes in the fosfomycin biosynthetic gene cluster of streptomyces wedmorensis confer high-level fosfomycin resistance on escherichia coli. to elucidate their functions, the foma and fomb genes were overexpressed in e. coli and the gene products were characterized. the recombinant foma protein converted fosfomycin to fosfomycin monophosphate, which was inactive on e. coli, in the presence of a magnesium ion and atp. on the other hand, the recombinant fomb protein did n ... | 2000 | 10681332 |
| arabidopsis cytochrome p450s that catalyze the first step of tryptophan-dependent indole-3-acetic acid biosynthesis. | plants synthesize numerous secondary metabolites that are used as developmental signals or as defense against pathogens. tryptophan (trp)-derived secondary metabolites include camalexin, indole glucosinolates, and indole-3-acetic acid (iaa); however, the steps in their synthesis from trp or its precursors remain unclear. we have identified two arabidopsis cytochrome p450s (cyp79b2 and cyp79b3) that can convert trp to indole-3-acetaldoxime (iaox), a precursor to iaa and indole glucosinolates. | 2000 | 10681464 |
| the gene coding for the hrp pilus structural protein is required for type iii secretion of hrp and avr proteins in pseudomonas syringae pv. tomato. | bacterial surface appendages called pili often are associated with dna and/or protein transfer between cells. the exact function of pili in the transfer process is not understood and is a matter of considerable debate. the hrp pilus is assembled by the hrp type iii protein secretion system of pseudomonas syringae pv. tomato (pst) strain dc3000. in this study, we show that the hrpa gene, which encodes the major subunit of the hrp pilus, is required for secretion of putative virulence proteins, su ... | 2000 | 10681465 |
| functional analysis of pvds, an iron starvation sigma factor of pseudomonas aeruginosa. | in pseudomonas aeruginosa, iron modulates gene expression through a cascade of negative and positive regulatory proteins. the master regulator fur is involved in iron-dependent repression of several genes. one of these genes, pvds, was predicted to encode a putative sigma factor responsible for the transcription of a subset of genes of the fur regulon. pvds appears to belong to a structurally and functionally distinct subgroup of the extracytoplasmic function family of alternative sigma factors. ... | 2000 | 10692351 |
| identification of genes in the rosr regulon of rhizobium etli. | rosr is a determinant of nodulation competitiveness and cell surface characteristics of rhizobium etli and has sequence similarity to a family of transcriptional repressors. to understand how rosr affects these phenotypes, we mutagenized a rosr mutant derivative of r. etli strain ce3 with a mini-tn5 that contains a promoterless gusa gene at one end, which acts as a transcriptional reporter. using a mass-mating technique, we introduced rosr into each mutant in trans and screened for mutants that ... | 2000 | 10692377 |
| the right end of the vir region of an octopine-type ti plasmid contains four new members of the vir regulon that are not essential for pathogenesis. | we sequenced the vird-vire, vire-virf, and virf-t-dna intergenic regions of an octopine ti plasmid. four newly described genes were induced by the vir gene inducer acetosyringone, two of which are conserved in the nopaline-type ti plasmid ptic58. one gene resembles a family of phosphatase genes. each of these genes is dispensable for tumorigenesis. | 2000 | 10692388 |
| frequency and biodiversity of 2,4-diacetylphloroglucinol-producing bacteria isolated from the maize rhizosphere at different stages of plant growth. | a pseudomonas 2,4-diacetylphloroglucinol (dapg)-producing population that occurred naturally on the roots, in rhizosphere soil of zea mays and in the nonrhizosphere soil was investigated in order to assess the microbial diversity at five stages of plant growth. a total of 1,716 isolates were obtained, and 188 of these isolates were able to produce dapg. dapg producers were isolated at each stage of plant growth, indicating that the maize rhizosphere is colonized by natural dapg producers through ... | 2000 | 10698757 |
| characterization and determination of origin of lactic acid bacteria from a sorghum-based fermented weaning food by analysis of soluble proteins and amplified fragment length polymorphism fingerprinting. | the group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known, and these organisms have been characterized extensively by using different techniques. in this study, 180 lactic acid bacterial strains isolated from sorghum powder (44 strains) and from corresponding fermented (93 strains) and cooked fermented (43 strains) porridge samples that were prepared in 15 households were characterized by using biochemical and physiological methods, as well as by analyz ... | 2000 | 10698775 |
| 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 |
| identification of arabidopsis mutants exhibiting an altered hypersensitive response in gene-for-gene disease resistance. | a mutational study was carried out to isolate arabidopsis thaliana plants that exhibit full or partial disruption of the rps2-mediated hypersensitive response (hr) to pseudomonas syringae that express avrrpt2. five classes of mutants were identified including mutations at rps2, dnd mutations causing a "defense, no death" loss-of-hr phenotype, a lesion-mimic mutant that also exhibited an hr- phenotype, and a number of intermediate or partial-loss-of-hr mutants. surprisingly, many of these mutants ... | 2000 | 10707353 |
| syringolin-mediated activation of the pir7b esterase gene in rice cells is suppressed by phosphatase inhibitors. | inoculation of rice plants (oryza sativa) with the nonhost pathogen pseudomonas syringae pv. syringae leads to the activation of defense-related genes and ultimately to induced resistance against the rice blast fungus pyricularia oryzae. one of the molecular determinants of p. syringae pv. syringae that is recognized by the plant cells and evokes these defense responses is syringolin a, an elicitor that is secreted by the bacteria under appropriate conditions. in order to investigate signal tran ... | 2000 | 10707360 |
| salicylic acid mediated by the oxidative burst is a key molecule in local and systemic responses of cotton challenged by an avirulent race of xanthomonas campestris pv malvacearum. | we analyzed the production of reactive oxygen species, the accumulation of salicylic acid (sa), and peroxidase activity during the incompatible interaction between cotyledons of the cotton (gossypium hirsutum) cv reba b50/xanthomonas campestris pv malvacearum (xcm) race 18. sa was detected in petioles of cotyledons 6 h after infection and 24 h post inoculation in cotyledons and untreated leaves. the first peak of sa occurred 3 h after generation of superoxide (o(2)(.-)), and was inhibited by inf ... | 2000 | 10712539 |
| identification of two novel hrp-associated genes in the hrp gene cluster of xanthomonas oryzae pv. oryzae. | we have cloned a hrp gene cluster from xanthomonas oryzae pv. oryzae. bacteria with mutations in the hrp region have reduced growth in rice leaves and lose the ability to elicit a hypersensitive response (hr) on the appropriate resistant cultivars of rice and the nonhost plant tomato. a 12,165-bp portion of nucleotide sequence from the presumed left end and extending through the hrpb operon was determined. the region was most similar to hrp genes from xanthomonas campestris pv. vesicatoria and r ... | 2000 | 10714988 |
| purification and characterization of a catalase from the facultatively psychrophilic bacterium vibrio rumoiensis s-1(t) exhibiting high catalase activity. | catalase from the facultatively psychrophilic bacterium vibrio rumoiensis s-1(t), which was isolated from an environment exposed to h(2)o(2) and exhibited high catalase activity, was purified and characterized, and its localization in the cell was determined. its molecular mass was 230 kda, and the molecule consisted of four identical subunits. the enzyme, which was not apparently reduced by dithionite, showed a soret peak at 406 nm in a resting state. the catalytic activity was 527,500 u. mg of ... | 2000 | 10714995 |
| characterization of the gene cluster involved in isoprene metabolism in rhodococcus sp. strain ad45. | the genes involved in isoprene (2-methyl-1,3-butadiene) utilization in rhodococcus sp. strain ad45 were cloned and characterized. sequence analysis of an 8.5-kb dna fragment showed the presence of 10 genes of which 2 encoded enzymes which were previously found to be involved in isoprene degradation: a glutathione s-transferase with activity towards 1,2-epoxy-2-methyl-3-butene (isoi) and a 1-hydroxy-2-glutathionyl-2-methyl-3-butene dehydrogenase (isoh). furthermore, a gene encoding a second gluta ... | 2000 | 10715003 |
| molecular and biological analysis of eight genetic islands that distinguish neisseria meningitidis from the closely related pathogen neisseria gonorrhoeae. | the pathogenic species neisseria meningitidis and neisseria gonorrhoeae cause dramatically different diseases despite strong relatedness at the genetic and biochemical levels. n. meningitidis can cross the blood-brain barrier to cause meningitis and has a propensity for toxic septicemia unlike n. gonorrhoeae. we previously used subtractive hybridization to identify dna sequences which might encode functions specific to bacteremia and invasion of the meninges because they are specific to n. menin ... | 2000 | 10722605 |
| arabidopsis rela/spot homologs implicate (p)ppgpp in plant signaling. | arabidopsis rpp5 is a member of a large class of pathogen resistance genes encoding nucleotide-binding sites and leucine-rich repeat domains. yeast two-hybrid analysis showed that rpp5 specifically interacts with at-rsh1, an arabidopsis rela/spot homolog. in escherichia coli, rela and spot determine the level of guanosine tetraphosphate (ppgpp) and guanosine pentaphosphate (pppgpp), which are the effector nucleotides of the bacterial stringent response. functional analysis in e. coli and in stre ... | 2000 | 10725385 |
| molecular cloning of a soybean class iii beta-1,3-glucanase gene that is regulated both developmentally and in response to pathogen infection. | we isolated and characterized a soybean gene (sgn1) encoding a basic beta-1,3-glucanase that is a plant class iii isoform of beta-1,3-glucanase. the deduced amino acid sequence of the sgn1 gene is similar to that of the pr-q'b gene, the basic class iii beta-1,3-glucanase of tomato. based on rna blot hybridization, sgn1 gene expression was detected in all tissues of 4-day old seedlings, but it was present only in root tissue of 30-day old plants. gus expression analysis carried out in transgenic ... | 2000 | 10725560 |
| a novel phenanthrene dioxygenase from nocardioides sp. strain kp7: expression in escherichia coli. | nocardioides sp. strain kp7 grows on phenanthrene but not on naphthalene. this organism degrades phenanthrene via 1-hydroxy-2-naphthoate, o-phthalate, and protocatechuate. the genes responsible for the degradation of phenanthrene to o-phthalate (phd) were found by southern hybridization to reside on the chromosome. a 10.6-kb dna fragment containing eight phd genes was cloned and sequenced. the phda, phdb, phdc, and phdd genes, which encode the alpha and beta subunits of the oxygenase component, ... | 2000 | 10735855 |
| roles of horizontal gene transfer and gene integration in evolution of 1,3-dichloropropene- and 1,2-dibromoethane-degradative pathways. | the haloalkane-degrading bacteria rhodococcus rhodochrous ncimb13064, pseudomonas pavonaceae 170, and mycobacterium sp. strain gp1 share a highly conserved haloalkane dehalogenase gene (dhaa). here, we describe the extent of the conserved dhaa segments in these three phylogenetically distinct bacteria and an analysis of their flanking sequences. the dhaa gene of the 1-chlorobutane-degrading strain ncimb13064 was found to reside within a 1-chlorobutane catabolic gene cluster, which also encodes a ... | 2000 | 10735862 |
| mechanism of inactivation of ornithine transcarbamoylase by ndelta -(n'-sulfodiaminophosphinyl)-l-ornithine, a true transition state analogue? crystal structure and implications for catalytic mechanism. | the crystal structure is reported at 1.8 a resolution of escherichia coli ornithine transcarbamoylase in complex with the active derivative of phaseolotoxin from pseudomonas syringae pv. phaseolicola, n(delta)-(n'-sulfodiaminophosphinyl)-l-ornithine. electron density reveals that the complex is not a covalent adduct as previously thought. kinetic data confirm that n(delta)-(n'-sulfodiaminophosphinyl)-l-ornithine exhibits reversible inhibition with a half-life in the order of approximately 22 h a ... | 2000 | 10747936 |
| inorganic polyphosphate is needed for swimming, swarming, and twitching motilities of pseudomonas aeruginosa. | polyphosphate kinase (ppk), encoded by the ppk gene, is the principal enzyme in many bacteria for the synthesis of inorganic polyphosphate (poly p) from atp. a knockout mutant in the ppk gene of pseudomonas aeruginosa pao1 is impaired in flagellar swimming motility on semisolid agar plates. the mutant is deficient in type iv pili-mediated twitching motility and in a "swarming motility" previously unobserved in p. aeruginosa. in swarming cultures, the polar monotrichous bacteria have differentiat ... | 2000 | 10758151 |
| atbi-1, a plant homologue of bax inhibitor-1, suppresses bax-induced cell death in yeast and is rapidly upregulated during wounding and pathogen challenge. | extensive searches have so far failed to identify functional plant homologues of the mammalian apoptotic machinery. here we report the isolation and characterisation of an arabidopsis thaliana homologue of human bax inhibitor-1, atbi-1, isolated during a differential screen of plants challenged with the phytopathogen pseudomonas syringae. atbi is a member of a small gene family in arabidopsis, members of which display extensive amino acid identity to human bi-1. atbi-1 is also functionally simil ... | 2000 | 10758491 |
| 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 |
| structure of the o polysaccharide and serological classification of pseudomonas syringae pv. ribicola ncppb 1010. | the o polysaccharide (ops) moiety of the lipopolysaccharide (lps) of a phytopathogenic bacterium pseudomonas syringae pv. ribicola ncppb 1010 was studied by sugar and methylation analyses, smith degradation, and 1h- and 13c-nmr spectroscopy, including 2d cosy, tocsy, noesy and h-detected 1h,13c hmqc experiments. the ops structure was elucidated, and shown to be composed of branched pentasaccharide repeating units (o repeats) of two types, major (1) and minor (2), differing in the position of sub ... | 2000 | 10759863 |
| the gacs sensor kinase regulates alginate and poly-beta-hydroxybutyrate production in azotobacter vinelandii. | azotobacter vinelandii produces two polymers: the extracellular polysaccharide alginate and the intracellular polyester poly-beta-hydroxybutyrate (phb). a cosmid clone (psmu588) from an a. vinelandii gene library diminished alginate production by a. vinelandii mucoid strain atcc 9046. the nucleotide sequence and predicted amino acid sequence of the locus responsible for the mucoidy suppression revealed 65% identity to pseudomonas gacs, a transmembrane sensor kinase of the two-component regulator ... | 2000 | 10762268 |
| rpma is required for nonopsonic phagocytosis of pseudomonas aeruginosa. | pseudomonas aeruginosa causes severe respiratory tract infections in patients with cystic fibrosis (cf). we have been examining nonopsonic phagocytosis of p. aeruginosa by macrophages. to study the p. aeruginosa-macrophage interaction at the molecular level, we have constructed a transposon tn5g bank in a clinical isolate of p. aeruginosa (strain 4020) and identified mutants resistant to nonopsonic phagocytosis. phagocytosis-resistant mutants were enriched by passaging the transposon bank over 1 ... | 2000 | 10768936 |
| syringomycin e inhibition of saccharomyces cerevisiae: requirement for biosynthesis of sphingolipids with very-long-chain fatty acids and mannose- and phosphoinositol-containing head groups. | syringomycin e is an antifungal cyclic lipodepsinonapeptide that inhibits the growth of saccharomyces cerevisiae by interaction with the plasma membrane. a screen conducted to find the yeast genes necessary for its fungicidal action identified two novel syringomycin e response genes, syr3 and syr4. a syr3 mutant allele was complemented by elo2 and elo3. these genes encode enzymes that catalyze the elongation of sphingolipid very long chain fatty acids. tetrad analysis showed that syr3 was elo2. ... | 2000 | 10770748 |
| 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 |
| haloalkane-utilizing rhodococcus strains isolated from geographically distinct locations possess a highly conserved gene cluster encoding haloalkane catabolism. | the sequences of the 16s rrna and haloalkane dehalogenase (dhaa) genes of five gram-positive haloalkane-utilizing bacteria isolated from contaminated sites in europe, japan, and the united states and of the archetypal haloalkane-degrading bacterium rhodococcus sp. strain ncimb13064 were compared. the 16s rrna gene sequences showed less than 1% sequence divergence, and all haloalkane degraders clearly belonged to the genus rhodococcus. all strains shared a completely conserved dhaa gene, suggesti ... | 2000 | 10781539 |
| the arcb sensor kinase of escherichia coli: genetic exploration of the transmembrane region. | the arc two-component signal transduction system of escherichia coli regulates the expression of numerous operons in response to respiratory growth conditions. cellular redox state or proton motive force (delta(h(+))) has been proposed to be the signal for the membrane-associated arcb sensor kinase. this study provided evidence for a short arcb periplasmic bridge that contains a his47. the dispensability of this amino acid, the only amino acid with a pk in the physiological range, renders the de ... | 2000 | 10781568 |
| leucine aminopeptidases: the ubiquity of lap-n and the specificity of lap-a. | the wound-induced leucine aminopeptidase (ec 3.4.11.1) genes, lapa1 and lapa2, from tomato (lycopersicon esculentum mill.) were isolated and characterized. the genes were organized in a tandem array with approximately 6 kb separating their coding regions. quantitation of lapa mrna levels in conjunction with nuclear run-on experiments indicated that lapa genes were primarily under transcriptional control after wounding and infection with pseudomonas syringae pv. tomato. in contrast, actin genes w ... | 2000 | 10787049 |
| development of a highly sensitive nested-pcr procedure using a single closed tube for detection of erwinia amylovora in asymptomatic plant material. | a novel method, which involves a nested pcr in a single closed tube, was developed for the sensitive detection of erwinia amylovora in plant material. the external and internal primer pairs used had different annealing temperatures and directed the amplification of a specific dna fragment from plasmid pea29. the procedure involved two consecutive pcrs, the first of which was performed at a higher annealing temperature that allowed amplification only by the external primer pair. using pure cultur ... | 2000 | 10788384 |
| 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 |
| plant species and plant incubation conditions influence variability in epiphytic bacterial population size. | the influences of plant species and plant incubation conditions on the variability in bacterial population sizes among leaves were investigated in field and growth chamber studies. pseudomonas syringae strains tlp2 and cit7 were inoculated onto plants and population sizes were measured at intervals after inoculation. total bacterial population sizes were also assessed in field studies. levels of leaf-to-leaf variability in both p. syringae population size and bacterial community size differed si ... | 2000 | 10790512 |
| simulation of fungal-mediated cell death by fumonisin b1 and selection of fumonisin b1-resistant (fbr) arabidopsis mutants. | fumonisin b1 (fb1), a programmed cell death-eliciting toxin produced by the necrotrophic fungal plant pathogen fusarium moniliforme, was used to simulate pathogen infection in arabidopsis. plants infiltrated with 10 microm fb1 and seedlings transferred to agar media containing 1 microm fb1 develop lesions reminiscent of the hypersensitive response, including generation of reactive oxygen intermediates, deposition of phenolic compounds and callose, accumulation of phytoalexin, and expression of p ... | 2000 | 11041878 |
| hrt gene function requires interaction between a nac protein and viral capsid protein to confer resistance to turnip crinkle virus. | an arabidopsis protein was found to interact specifically with the capsid protein (cp) of turnip crinkle virus (tcv) through yeast two-hybrid screening. this protein, designated tip (for tcv-interacting protein), was found to be a member of the recently recognized nac family of proteins. nac proteins have been implicated in the regulation of development of plant embryos and flowers. tip alone was able to activate expression of reporter genes in yeast if fused to a dna binding domain, suggesting ... | 2000 | 11041886 |
| molecular analysis of thermoregulation of phaseolotoxin-resistant ornithine carbamoyltransferase (argk) from pseudomonas syringae pv. phaseolicola. | the phaseolotoxin-resistant ornithine carbamoyltransferase (roct) and phaseolotoxin are produced by pseudomonas syringae pv. phaseolicola at 18 degrees c but not at 28 degrees c. at 28 degrees c, the pathogen produces a protein(s) that binds (in vitro) to a 485-bp fragment (thermoregulatory region, trr) from a heterologous clone from the pathogen genomic library, which in multiple copies overrides thermoregulation of phaseolotoxin production in wild-type cells (k. b. rowley, d. e. clements, m. m ... | 2000 | 11043468 |
| cdna cloning and characterization of a plant protein that may be associated with the harpinpss-mediated hypersensitive response. | hypersensitive response-assisting protein (hrap) is a novel plant protein that can intensify the harpinpss-mediated hypersensitive response (hr) in harpinpss-insensitive plants, such as the vegetative stage of sweet pepper. in this report, we identified a hrap cdna clone from sweet pepper (capsicum annuum cv. ecw). the sequence of this cdna clone showed no appreciable similarity to any other known sequences. however, it contained three positively charged regions, a typical signal peptide and a c ... | 2000 | 11052195 |
| escherichia coli tehb requires s-adenosylmethionine as a cofactor to mediate tellurite resistance. | the escherichia coli chromosomal determinant for tellurite resistance consists of two genes (teha and tehb) which, when expressed on a multicopy plasmid, confer resistance to k(2)teo(3) at 128 microg/ml, compared to the mic of 2 microg/ml for the wild type. tehb is a cytoplasmic protein which possesses three conserved motifs (i, ii, and iii) found in s-adenosyl-l-methionine (sam)-dependent non-nucleic acid methyltransferases. replacement of the conserved aspartate residue in motif i by asparagin ... | 2000 | 11053398 |
| potentiation of pathogen-specific defense mechanisms in arabidopsis by beta -aminobutyric acid. | the nonprotein amino acids gamma-aminobutyric acid (gaba) and beta-aminobutyric acid (baba) have known biological effects in animals and plants. their mode of action has been the object of thorough research in animals but remains unclear in plants. our objective was to study the mode of action of baba in the protection of arabidopis plants against virulent pathogens. baba protected arabidopsis against the oomycete pathogen peronospora parasitica through activation of natural defense mechanisms o ... | 2000 | 11058166 |
| regulation of hrp genes and type iii protein secretion in erwinia amylovora by hrpx/hrpy, a novel two-component system, and hrps. | two novel regulatory components, hrpx and hrpy, of the hrp system of erwinia amylovora were identified. the hrpxy operon is expressed in rich media, but its transcription is increased threefold by low ph, nutrient, and temperature levels--conditions that mimic the plant apoplast. hrpxy is autoregulated and directs the expression of hrpl; hrpl, in turn, activates transcription of other loci in the hrp gene cluster (z.-m. wei and s. v. beer, j. bacteriol. 177:6201-6210, 1995). the deduced amino -a ... | 2000 | 11059492 |
| transposon insertion in the ftsk gene impairs in planta growth and lesion-forming abilities in pseudomonas syringae pv. syringae b728a. | a tn5 insertion in the ftsk gene of pseudomonas syringae pv. syringae b728a impaired brown spot lesion formation on phaseolus vulgaris, the ability to grow within bean leaves, and swarming ability on semisolid agar. plasmids containing the ftsk gene were sufficient to complement the original tn5 mutant for lesion formation and swarming and partially restored in planta growth. | 2000 | 11059493 |
| evaluation of fluorescence-based amplified fragment length polymorphism analysis for molecular typing in hospital epidemiology: comparison with pulsed-field gel electrophoresis for typing strains of vancomycin-resistant enterococcus faecium. | fluorescence-based amplified fragment length polymorphism (fbaflp) is a novel assay based on the fluorescent analysis of an amplified subset of restriction fragments. the fbaflp assay involves the selective pcr amplification of restriction fragments from a total digest of genomic dna. the ligation of adapters with primer-specific sites coupled with primers containing selective nucleotides allowed the full potential of pcr to be realized while maintaining the advantages of restriction endonucleas ... | 2000 | 11060068 |
| excision from trna genes of a large chromosomal region, carrying avrpphb, associated with race change in the bean pathogen, pseudomonas syringae pv. phaseolicola. | pseudomonas syringae pv. phaseolicola (pph) race 4 strain 1302a carries avirulence gene avrpphb. strain rj3, a sectoral variant from a 1302a culture, exhibited an extended host range in cultivars of bean and soybean resulting from the absence of avrpphb from the rj3 chromosome. complementation of rj3 with avrpphb restored the race 4 phenotype. both strains showed similar in planta growth in susceptible bean cultivars. analysis of rj3 indicated loss of > 40 kb of dna surrounding avrpphb. collinea ... | 2000 | 11069647 |
| three unique mutants of arabidopsis identify eds loci required for limiting growth of a biotrophic fungal pathogen. | to identify components of the defense response that limit growth of a biotrophic fungal pathogen, we isolated arabidopsis mutants with enhanced disease susceptibility to erysiphe orontii. our initial characterization focused on three mutants, eds14, eds15, and eds16. none of these is considerably more susceptible to a virulent strain of the bacterial pathogen pseudomonas syringae pv. maculicola (psm). all three mutants develop a hypersensitive response when infiltrated with psm expressing the av ... | 2000 | 11069695 |
| role of azotobacter vinelandii muca and mucc gene products in alginate production. | azotobacter vinelandii produces the exopolysaccharide alginate, which is essential for its differentiation to desiccation-resistant cysts. in different bacterial species, the alternative sigma factor sigma(e) regulates the expression of functions related to the extracytoplasmic compartments. in a. vinelandii and pseudomonas aeruginosa, the sigma(e) factor (algu) is essential for alginate production. in both bacteria, the activity of this sigma factor is regulated by the product of the muca, mucb ... | 2000 | 11073894 |
| multicomponent transcriptional regulation at the complex promoter of the exopolysaccharide i biosynthetic operon of ralstonia solanacearum. | high-level transcription of eps, an operon encoding biosynthesis of an exopolysaccharide virulence factor of the phytopathogen ralstonia (pseudomonas) solanacearum, requires the products of at least seven regulatory genes (phca, phcb, xpsr, vsra-vsrd, and vsrb-vsrc), which are organized in three converging signal transduction cascades. because xpsr and the vsrb-vsrc two-component system are the most downstream cascade components required for activation of eps, we explored how these components co ... | 2000 | 11073909 |
| catalase-peroxidases of legionella pneumophila: cloning of the kata gene and studies of kata function. | legionella pneumophila, the causative organism of legionnaires' pneumonia, contains two enzymes with catalatic and peroxidatic activity, kata and katb. to address the issue of redundant, overlapping, or discrete in vivo functions of highly homologous catalase-peroxidases, the gene for kata was cloned and its function was studied in l. pneumophila and escherichia coli and compared with prior studies of katb in this laboratory. kata is induced during exponential growth and is the predominant perox ... | 2000 | 11073912 |
| molecular signals required for type iii secretion and translocation of the xanthomonas campestris avrbs2 protein to pepper plants. | strains of xanthomonas campestris pv. vesicatoria (xcv) carrying avrbs2 are specifically recognized by bs2 pepper plants, resulting in localized cell death and plant resistance. agrobacterium-mediated transient expression of the xcv avrbs2 gene in plant cells results in bs2-dependent cell death, indicating that the avrbs2 protein alone is sufficient for the activation of disease resistance-mediated cell death in planta. we now provide evidence that avrbs2 is secreted from xcv and that secretion ... | 2000 | 11078519 |
| local and systemic induction of two defense-related subtilisin-like protease promoters in transgenic arabidopsis plants. luciferin induction of pr gene expression. | following a pathogenic attack, plants are able to mount a defense response with the coordinated activation of a battery of defense-related genes. in this study we have characterized the mode of expression of the p69b and p69c genes from tomato (lycopersicon esculentum mill.), which encodes two closely related subtilisin-like proteases associated with the defense response. we have compared the mode of gene regulation in heterologous transgenic arabidopsis plants harboring promoter-beta-glucuronid ... | 2000 | 11080282 |
| a leaf lipoxygenase of potato induced specifically by pathogen infection. | lipoxygenase (lox) activity has been identified consistently during pathogen-induced defense responses. here we report the involvement of a specific leaf lox gene of potato (solanum tuberosum), designated potlx-3 (genbank/embl accession no. u60202), in defense responses against pathogens. the sequence of potlx-3 does not match any other lox genes of potato and has the greatest match to a tobacco lox gene that contributes to a resistance mechanism against phytophthora parasitica var nicotianae. p ... | 2000 | 11080289 |
| identification and characterization of yersinia enterocolitica genes induced during systemic infection. | yersinia enterocolitica is one of three pathogenic yersinia species that share a tropism for lymphoid tissues. however, infection of an immunocompromised host is likely to result in a systemic infection, which is often fatal. little is known about the bacterial proteins needed to establish such an infection. the genes that encode these virulence factors are likely to be active only during systemic infection. a library of random cat fusions was used to inoculate balb/c mice. fusions expressed dur ... | 2000 | 11083775 |
| a telomeric avirulence gene determines efficacy for the rice blast resistance gene pi-ta. | genetic mapping showed that the rice blast avirulence gene avr-pita is tightly linked to a telomere on chromosome 3 in the plant pathogenic fungus magnaporthe grisea. avr-pita corresponds in gene-for-gene fashion to the disease resistance (r) gene pi-ta. analysis of spontaneous avr-pita(-) mutants indicated that the gene is located in a telomeric 6.5-kb bglii restriction fragment. cloning and dna sequencing led to the identification of a candidate gene with features typical of metalloproteases. ... | 2000 | 11090206 |
| arabidopsis dth9 mutation identifies a gene involved in regulating disease susceptibility without affecting salicylic acid-dependent responses. | to determine which components of the plant defense response make important contributions to limiting pathogen attack, an m(2) mutagenized population of a transgenic arabidopsis line was screened for mutants showing constitutive expression of beta-glucuronidase activity driven by the promoter region of the cevi-1 gene. the cevi-1 gene originally was isolated from tomato plants and has been shown to be induced in susceptible varieties of tomato plants by virus infection in a salicylic acid-indepen ... | 2000 | 11090213 |
| metabolism of acyl-homoserine lactone quorum-sensing signals by variovorax paradoxus. | acyl-homoserine lactones (acyl-hsls) serve as dedicated cell-to-cell signaling molecules in many species of the class proteobacteria. we have addressed the question of whether these compounds can be degraded biologically. a motile, rod-shaped bacterium was isolated from soil based upon its ability to utilize n-(3-oxohexanoyl)-l-homoserine lactone as the sole source of energy and nitrogen. the bacterium was classified as a strain of variovorax paradoxus. the v. paradoxus isolate was capable of gr ... | 2000 | 11092851 |
| evidence for a role of rpoe in stressed and unstressed cells of marine vibrio angustum strain s14. | we report the cloning, sequencing, and characterization of the rpoe homolog in vibrio angustum s14. the rpoe gene encodes a protein with a predicted molecular mass of 19.4 kda and has been demonstrated to be present as a single-copy gene by southern blot analysis. the deduced amino acid sequence of rpoe is most similar to that of the rpoe homolog of sphingomonas aromaticivorans, sigma(24), displaying sequence similarity and identity of 63 and 43%, respectively. northern blot analysis demonstrate ... | 2000 | 11092857 |
| molecular evolution of virulence in natural field strains of xanthomonas campestris pv. vesicatoria. | the avrbs2 avirulence gene of the bacterial plant pathogen xanthomonas campestris pv. vesicatoria triggers disease resistance in pepper plants containing the bs2 resistance gene and contributes to bacterial virulence on susceptible host plants. we studied the effects of the pepper bs2 gene on the evolution of avrbs2 by characterizing the molecular basis for virulence of 20 x. campestris pv. vesicatoria field strains that were isolated from disease spots on previously resistant bs2 pepper plants. ... | 2000 | 11092868 |
| phosphorylation of cors and corr, regulatory proteins that modulate production of the phytotoxin coronatine in pseudomonas syringae. | production of the phytotoxin coronatine (cor) in pseudomonas syringae pv. glycinea pg4180 is controlled by a modified two-component regulatory system consisting of three genes, corr, corp, and cors. corr and corp show similarity to response regulators, and cors is related to histidine protein kinases that function as environmental sensors. in this study, corr, corp and the cytoplasmic portion of cors, designated corsdelta, were overproduced in p. syringae as translational fusions to the maltose- ... | 2000 | 11094272 |
| sequence diversity of rula among natural isolates of pseudomonas syringae and effect on function of rulab-mediated uv radiation tolerance. | the rulab locus confers tolerance to uv radiation and is borne on plasmids of the ppt23a family in pseudomonas syringae. we sequenced 14 rula alleles from p. syringae strains representing seven pathovars and found sequence differences of 1 to 12% within pathovar syringae, and up to 15% differences between pathovars. since the sequence variation within rula was similar to that of p. syringae chromosomal alleles, we hypothesized that rulab has evolved over a long time period in p. syringae. a phyl ... | 2000 | 11097885 |
| composition of soil microbial communities enriched on a mixture of aromatic hydrocarbons. | soil contaminated with c5+, which contained benzene (45%, wt/wt), dicyclopentadiene (dcpd) plus cyclopentadiene (together 20%), toluene (6%), styrene (3%), xylenes (2%), naphthalene (2%), and smaller quantities of other compounds, served as the source for isolation of 55 genomically distinct bacteria (standards). use of benzene as a substrate by these bacteria was most widespread (31 of 44 standards tested), followed by toluene (23 of 44), xylenes (14 of 44), styrene (10 of 44), and naphthalene ... | 2000 | 11097903 |
| biogeography and degree of endemicity of fluorescent pseudomonas strains in soil. | fluorescent pseudomonas strains were isolated from 38 undisturbed pristine soil samples from 10 sites on four continents. a total of 248 isolates were confirmed as pseudomonas sensu stricto by fluorescent pigment production and group-specific 16s ribosomal dna (rdna) primers. these isolates were analyzed by three molecular typing methods with different levels of resolution: 16s rdna restriction analysis (ardra), 16s-23s rdna intergenic spacer-restriction fragment length polymorphism (its-rflp) a ... | 2000 | 11097926 |
| functional tn5393-like transposon in the r plasmid pras2 from the fish pathogen aeromonas salmonicida subspecies salmonicida isolated in norway. | tn5393c containing stra-strb was identified as part of r plasmid pras2 from the fish pathogen aeromonas salmonicida subsp. salmonicida. this is the first time an intact and active transposon in the tn5393 family has been reported in an ecological niche other than an agricultural habitat. | 2000 | 11097945 |
| elicitor-induced defence reactions in cell suspension cultures of soybean cultivars. | suspension cultured soybean (glycine max [l.] merr.) cells of four cultivars (wilis, lumut, kalmit, doko rc) were compared for their response to different fungal and bacterial elicitors. cells were treated either with crude cell wall extracts of the fungal pathogens phytophthora sojae (pmg-elicitor) and rhizoctonia solani (riso-elicitor) or with two isolates of the bacterial pathogen pseudomonas syringae pv. glycinea (psg01/02) and a broad spectrum of antimicrobial defence reactions was measured ... | 2000 | 11098822 |
| the pseudomonas syringae avrrpt2 gene product promotes pathogen virulence from inside plant cells. | several bacterial avr genes have been shown to contribute to virulence on susceptible plants lacking the corresponding resistance (r) gene. the mechanisms by which avr genes promote parasitism and disease, however, are not well understood. we investigated the role of the pseudomonas syringae pv. tomato avrrpt2 gene in pathogenesis by studying the interaction of p. syringae pv. tomato strain pstdc3000 expressing avrrpt2 with several arabidopsis thaliana lines lacking the corresponding r gene, rps ... | 2000 | 11106023 |
| elicitation of hypersensitive cell death by extracellularly targeted hrpzpsph produced in planta. | the ability of the pseudomonas syringae pv. phaseolicola harpin (hrpzpsph) to elicit hypersensitive response was investigated in three nicotiana genotypes. the hrpzpsph gene was placed under chemical regulation (tetracycline induction) in tetr+ nicotiana tabacum cv. wisconsin 38 (w38) or was transiently expressed in n. benthamiana following infection with a pvx-derived vector and in three nicotiana genotypes by agroinfiltration. the constructs were designed to express either the canonical form o ... | 2000 | 11106029 |
| signal recognition and transduction mediated by the tomato pto kinase: a paradigm of innate immunity in plants. | plant disease resistance is the result of an innate host defense mechanism, which relies on the ability of the plant to recognize pathogen invasion and to efficiently mount defense responses. in tomato, resistance to the pathogen pseudomonas syringae is mediated by the specific interaction between the plant serine/threonine kinase pto and the bacterial protein avrpto. this article reviews molecular and biochemical properties that confer to pto the capability to function as an intracellular recep ... | 2000 | 11113378 |
| pathogen-induced map kinases in tobacco. | the activation of two tobacco map kinases, sipk and wipk, by a variety of pathogen-associated stimuli and other stresses have been analyzed (table 1). sipk was activated by sa, a cwd carbohydrate elicitor and two elicitins from phytophthora spp, bacterial harpin, tmv, and avr9 from cladosporium fulvum. in addition to these pathogen-associated stimuli, wounding also activated sipk, suggesting that this enzyme is involved in multiple signal transduction pathways. in all cases tested, sipk activati ... | 2000 | 10533199 |
| the virr response regulator from clostridium perfringens binds independently to two imperfect direct repeats located upstream of the pfoa promoter. | regulation of toxin production in the gram-positive anaerobe clostridium perfringens occurs at the level of transcription and involves a two-component signal transduction system. the sensor histidine kinase is encoded by the virs gene, while its cognate response regulator is encoded by the virr gene. we have constructed a virr expression plasmid in escherichia coli and purified the resultant his-tagged virr protein. gel mobility shift assays demonstrated that virr binds to the region upstream of ... | 2000 | 10613863 |
| production and comparison of peptide siderophores from strains of distantly related pathovars of pseudomonas syringae and pseudomonas viridiflava lmg 2352. | the production of peptide siderophores and the variation in siderophore production among strains of pseudomonas syringae and pseudomonas viridiflava were investigated. an antibiose test was used to select a free amino acid-containing agar medium favorable for production of fluorescent siderophores by two p. syringae strains. a culture technique in which both liquid and solid asparagine-containing culture media were used proved to be reproducible and highly effective for inducing production of si ... | 2000 | 10618243 |
| 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 |