Publications

modulation of expression of the toxr regulon in vibrio cholerae by a member of the two-component family of response regulators.	the toxrs system in vibrio cholerae plays a central role in the modulation of virulence gene expression in response to environmental stimuli. an integration of multiple signalling inputs mediated by toxr, -s, and -t controls virulence gene expression leading to cholera toxin (ct) production. recently, we identified a new virulence locus, vara (virulence associated regulator), in classical v. cholerae o1 that positively controls transcription of tcpa, the major subunit of the toxin-coregulated pi ...	1998	9826365
cyp76c2, an arabidopsis thaliana cytochrome p450 gene expressed during hypersensitive and developmental cell death.	the characterisation of an arabidopsis thaliana cytochrome p450-encoding cdna clone, b72, preferentially expressed during the hypersensitive response (hr) provoked by the bacterial pathogen pseudomonas syringae pathovar maculicola, is reported. the b72 cdna clone corresponded to the cyp76c2 gene, which belongs to a small multigene family comprising four genes. hr-triggering bacteria harbouring different avirulence genes induced the accumulation of transcripts of this p450 gene. cyp76c2 gene expr ...	1998	9827554
characterization of corr, a transcriptional activator which is required for biosynthesis of the phytotoxin coronatine.	coronatine (cor) is a plasmid-encoded phytotoxin synthesized by several pathovars of phytopathogenic pseudomonas syringae. the cor biosynthetic gene cluster in p. syringae pv. glycinea pg4180 is encoded by a 32-kb region which contains both the structural and regulatory genes needed for cor synthesis. the regulatory region contains three genes: corp, cors, and corr. cors is thought to function as a histidine protein kinase, whereas corp and corr show relatedness to response regulators of the two ...	1998	9829934
combined physical and genetic map of the pseudomonas putida kt2440 chromosome.	a combined physical and genetic map of the pseudomonas putida kt2440 genome was constructed from data obtained by pulsed-field gel electrophoresis techniques (pfge) and southern hybridization. circular genome size was estimated at 6.0 mb by adding the sizes of 19 swai, 9 pmei, 6 paci, and 6 i-ceui fragments. a complete physical map was achieved by combining the results of (i) analysis of pfge of the dna fragments resulting from digestion of the whole genome with pmei, swai, i-ceui, and paci as w ...	1998	9829947
expression of the pseudomonas aeruginosa gentamicin resistance gene aacc3 in escherichia coli.	the pseudomonas aeruginosa aacc3 gene was expressed in escherichia coli after cloning of the single gene behind the strong tac promoter. in the original pseudomonas strain, aacc3 is preceded by cysc; together they form a single transcription unit. the ribosome-binding site and start codon of aacc3 are involved in a putative intercistronic hairpin, the stability of which interfered with the aminoglycoside resistance level. in northern blots, full-length transcripts comprising both cysc and aacc3 ...	1998	9835511
psychrotolerant bacteria isolated from arctic soil that degrade polychlorinated biphenyls at low temperatures	psychrotolerant polychlorinated biphenyl (pcb)-degrading bacteria were isolated at 7 degreesc from pcb-contaminated arctic soil by using biphenyl as the sole organic carbon source. these isolates were distinguished from each other by differences in substrates that supported growth and substrates that were oxidized. 16s ribosomal dna sequences suggest that these isolates are most closely related to the genus pseudomonas. total removal of aroclor 1242, and rates of removal of selected pcb congener ...	1998	9835569
ralstonia solanacearum pectin methylesterase is required for growth on methylated pectin but not for bacterial wilt virulence	ralstonia (pseudomonas) solanacearum causes bacterial wilt, a serious disease of many crop plants. the pathogen produces several extracellular plant cell wall-degrading enzymes, including polygalacturonases (pgs) and pectin methylesterase (pme). pme removes methyl groups from pectin, thereby facilitating subsequent breakdown of this cell wall component by pgs, which are known bacterial wilt virulence factors. r. solanacearum pgs could not degrade 93% methylated pectin unless the substrate was fi ...	1998	9835583
detection and isolation of novel rhizopine-catabolizing bacteria from the environment	microbial rhizopine-catabolizing (moc) activity was detected in serial dilutions of soil and rhizosphere washes. the activity observed generally ranged between 10(6) and 10(7) catabolic units per g, and the numbers of nonspecific culture-forming units were found to be approximately 10 times higher. a diverse set of 37 isolates was obtained by enrichment on scyllo-inosamine-containing media. however, none of the bacteria that were isolated were found to contain dna sequences homologous to the kno ...	1998	9835587
differential expression of a senescence-enhanced metallothionein gene in arabidopsis in response to isolates of peronospora parasitica and pseudomonas syringae.	the metallothionein gene, lsc54, shows increased expression during leaf senescence in brassica napus and arabidopsis thaliana. a number of abiotic and biotic stresses have been shown to induce senescence-like symptoms in plants and, to investigate this further, the promoter of the lsc54 gene was cloned and fused to the gus gene and transformed into arabidopsis. the promoter was highly induced during leaf senescence and also in response to wounding; histochemical analysis indicated that this indu ...	1998	9839466
inorganic cation transport and energy transduction in enterococcus hirae and other streptococci.	energy metabolism by bacteria is well understood from the chemiosmotic viewpoint. we know that bacteria extrude protons across the plasma membrane, establishing an electrochemical potential that provides the driving force for various kinds of physiological work. among these are the uptake of sugars, amino acids, and other nutrients with the aid of secondary porters and the regulation of the cytoplasmic ph and of the cytoplasmic concentration of potassium and other ions. bacteria live in diverse ...	1998	9841664
the virulence plasmid of yersinia, an antihost genome.	the 70-kb virulence plasmid enables yersinia spp. (yersinia pestis, y. pseudotuberculosis, and y. enterocolitica) to survive and multiply in the lymphoid tissues of their host. it encodes the yop virulon, an integrated system allowing extracellular bacteria to disarm the cells involved in the immune response, to disrupt their communications, or even to induce their apoptosis by the injection of bacterial effector proteins. this system consists of the yop proteins and their dedicated type iii sec ...	1998	9841674
potentiation of the oxidative burst and isoflavonoid phytoalexin accumulation by serine protease inhibitors	treatment of soybean (glycine max l. cv williams 82) cell-suspension cultures with pseudomonas syringae pv glycinea (psg) harboring an avirulence gene (avra) or with yeast elicitor resulted in an oxidative burst characterized by the accumulation of h2o2. this burst, and the resultant induction of glutathione s-transferase transcripts, occurred more rapidly and was more prolonged if cells were simultaneously treated with serine protease inhibitors such as phenylmethylsulfonyl fluoride (pmsf) or d ...	1998	9847125
the two-component regulators gacs and gaca influence accumulation of the stationary-phase sigma factor sigmas and the stress response in pseudomonas fluorescens pf-5.	three global regulators are known to control antibiotic production by pseudomonas fluorescens. a two-component regulatory system comprised of the sensor kinase gacs (previously called apda or lema) and gaca, a member of the fixj family of response regulators, is required for antibiotic production. a mutation in rpos, which encodes the stationary-phase sigma factor sigmas, differentially affects antibiotic production and reduces the capacity of stationary-phase cells of p. fluorescens to survive ...	1998	9852008
biosynthesis of the pseudomonas polyketide coronafacic acid requires monofunctional and multifunctional polyketide synthase proteins.	coronafacic acid (cfa) is the polyketide component of the phytotoxin coronatine, a virulence factor of the plant pathogen pseudomonas syringae. our current knowledge of polyketide biosynthesis largely is based on the analysis of polyketide synthases (pkss) in actinomycetes and other gram-positive bacteria. consequently, the cloning and characterization of the cfa biosynthetic gene cluster will contribute significantly to our knowledge of polyketide synthesis in pseudomonas. in this report, we de ...	1998	9860992
independent deletions of a pathogen-resistance gene in brassica and arabidopsis.	plant disease resistance (r) genes confer race-specific resistance to pathogens and are genetically defined on the basis of intra-specific functional polymorphism. little is known about the evolutionary mechanisms that generate this polymorphism. most r loci examined to date contain alternate alleles and/or linked homologs even in disease-susceptible plant genotypes. in contrast, the resistance to pseudomonas syringae pathovar maculicola (rpm1) bacterial resistance gene is completely absent (rpm ...	1998	9861058
the arabidopsis thaliana rpm1 disease resistance gene product is a peripheral plasma membrane protein that is degraded coincident with the hypersensitive response.	disease resistance in plants is often controlled by a gene-for-gene mechanism in which avirulence (avr) gene products encoded by pathogens are specifically recognized, either directly or indirectly, by plant disease resistance (r) gene products. members of the nbs-lrr class of r genes encode proteins containing a putative nucleotide binding site (nbs) and carboxyl-terminal leucine-rich repeats (lrrs). generally, nbs-lrr proteins do not contain predicted transmembrane segments or signal peptides, ...	1998	9861059
salmonella typhimurium encodes an sdia homolog, a putative quorum sensor of the luxr family, that regulates genes on the virulence plasmid.	quorum sensing is a phenomenon in which bacteria sense and respond to their own population density by releasing and sensing pheromones. in gram-negative bacteria, quorum sensing is often performed by the luxr family of transcriptional regulators, which affect phenotypes as diverse as conjugation, bioluminescence, and virulence gene expression. the gene encoding one luxr family member, named sdia (suppressor of cell division inhibition), is present in the escherichia coli genome. in this report, ...	1998	9495757
ethylene regulates the susceptible response to pathogen infection in tomato.	ethylene evolution occurs concomitantly with the progression of disease symptoms in response to many virulent pathogen infections in plants. a tomato mutant impaired in ethylene perception-never ripe-exhibited a significant reduction in disease symptoms in comparison to the wild type after inoculations of both genotypes with virulent bacterial (xanthomonas campestris pv vesicatoria and pseudomonas syringae pv tomato) and fungal (fusarium oxysporum f sp lycopersici) pathogens. bacterial spot dise ...	1998	9501111
exopolysaccharide ii production is regulated by salt in the halotolerant strain rhizobium meliloti efb1.	the halotolerant strain rhizobium meliloti efb1 modifies the production of extracellular polysaccharides in response to salt. efb1 colonies grown in the presence of 0.3 m nacl show a decrease in mucoidy, and in salt-supplemented liquid medium this organism produces 40% less exopolysaccharides. we isolated transposon-induced mutant that, when grown in the absence of salt, had a colony morphology (nonmucoid) similar to the colony morphology of the wild type grown in the presence of salt. calcofluo ...	1998	9501442
growth phase and temperature influence promoter activity, transcript abundance, and protein stability during biosynthesis of the pseudomonas syringae phytotoxin coronatine.	the plant-pathogenic bacterium pseudomonas syringae pv. glycinea pg4180.n9 synthesizes high levels of the polyketide phytotoxin coronatine (cor) at 18 degrees c, whereas no detectable toxin is produced at 28 degrees c. previously, we reported that the temperature-sensitive activation of three promoters within the cor biosynthetic gene cluster might explain thermoregulation of cor biosynthesis. the present study was aimed at furthering our understanding of the transcriptional as well as the postt ...	1998	9515901
reactive oxygen intermediates mediate a systemic signal network in the establishment of plant immunity.	recognition of an avirulent pathogen stimulates an oxidative burst generating o2- and h2o2, and these reactive oxygen intermediates (rois) cue the induction of defense genes and cell death in the development of a restricted lesion. this localized hypersensitive response (hr) is accompanied by the development of systemic acquired resistance to virulent pathogens. here we show that inoculation of arabidopsis leaves with avirulent pseudomonas syringae induces secondary oxidative bursts in discrete ...	1998	9529253
comparative biochemistry of the oxidative burst produced by rose and french bean cells reveals two distinct mechanisms	cultured cells of rose (rosa damascena) treated with an elicitor derived from phytophthora spp. and suspension-cultured cells of french bean (phaseolus vulgaris) treated with an elicitor derived from the cell walls of colletotrichum lindemuthianum both produced h2o2. it has been hypothesized that in rose cells h2o2 is produced by a plasma membrane nad(p)h oxidase (superoxide synthase), whereas in bean cells h2o2 is derived directly from cell wall peroxidases following extracellular alkalinizatio ...	1998	9536055
identification of a novel salmonella invasion locus homologous to shigella ipgde.	genes essential for salmonella typhimurium invasion have been localized to salmonella pathogenicity island 1 (spi1) on the chromosome. however, it is clear that other genes are required for the invasion process. mutations that abolish the spi1 invasion type iii secretion system do not significantly reduce invasion into chinese hamster ovary tissue culture cells. two invasion defective mutants were isolated by screening 2,500 tn10dtc insertion mutants of s. typhimurium in the tissue culture invas ...	1998	9537377
occurrence of thermoregulation of genes involved in coronatine biosynthesis among various pseudomonas syringae strains.	several pathovars of pseudomonas syringae produce the polyketide phytotoxin coronatine (cor). in the bacterial blight pathogen of soybean, p. syringae pv. glycinea pg4180, cor is produced at high levels at 18 degrees c whereas no toxin is synthesized at 28 degrees c. previously, activation of three promoters inside the cor biosynthetic gene cluster by a modified two-component regulatory system was shown to influence thermoregulation of cor biosynthesis. using phenotypic determination of cor synt ...	1998	9542107
characterization of the dominant and rare members of a young hawaiian soil bacterial community with small-subunit ribosomal dna amplified from dna fractionated on the basis of its guanine and cytosine composition.	the small-subunit ribosomal dna (rdna) diversity was found to be very high in a hawaiian soil community that might be expected to have lower diversity than the communities in continental soils because the hawaiian soil is geographically isolated and only 200 years old, is subjected to a constant climate, and harbors low plant diversity. since an underlying community structure could not be revealed by analyzing the total eubacterial rdna, we first fractionated the dna on the basis of guanine-plus ...	1998	9546163
uncoupling pr gene expression from npr1 and bacterial resistance: characterization of the dominant arabidopsis cpr6-1 mutant.	in arabidopsis, npr1 mediates the salicylic acid (sa)-induced expression of pathogenesis-related (pr) genes and systemic acquired resistance (sar). here, we report the identification of another component, cpr 6, that may function with npr1 in regulating pr gene expression. the dominant cpr 6-1 mutant expresses the sa/npr1-regulated pr genes (pr-1, bgl 2, and pr-5) and displays enhanced resistance to pseudomonas syringae pv maculicola es4326 and peronospora parasitica noco2 in the absence of sar ...	1998	9548982
expression of carboxymethylcellulase on the surface of escherichia coli using pseudomonas syringae ice nucleation protein.	ice-nucleation protein (inp), an outer membrane protein from pseudomonas syringae, is able to catalyze the ice crystal formation of supercooled water. it was exploited for anchoring of bacillus subtilis carboxymethylcellulase (cmcase) on the surface of escherichia coli. a surface anchoring vector, pginp21m, was created that contains the multicloning sites including bamhi, smai and ecori at the end of the 3' flanking region encoding the c-terminus of inp instead of the stop codon for subcloning t ...	1998	9549104
erwinia amylovora secretes dspe, a pathogenicity factor and functional avre homolog, through the hrp (type iii secretion) pathway.	erwinia amylovora was shown to secrete dspe, a pathogenicity factor of 198 kda and a functional homolog of avre of pseudomonas syringae pv. tomato. dspe was identified among the supernatant proteins isolated from cultures grown in an hrp gene-inducing minimal medium by immunodetection with a dspe-specific antiserum. secretion required an intact hrp pathway.	1998	9555912
histidine utilisation operon (hut) is upregulated at low temperature in the antarctic psychrotrophic bacterium pseudomonas syringae.	the antarctic psychrotrophic bacterium pseudomonas syringae was mutagenised using a transposon tn5-ot182 which facilitates identification of promoter fusions expressing the reporter gene (lacz) for beta-galactosidase. most mutants expressed beta-galactosidase both at optimal growth temperature (20-22 degrees c) and at low temperature (4 degrees c). but a small percentage of the mutants (approximately 5%) were unique in that they expressed beta-galactosidase activity predominantly at low temperat ...	1998	9561727
a tellurite-resistance genetic determinant from phytopathogenic pseudomonads encodes a thiopurine methyltransferase: evidence of a widely-conserved family of methyltransferases.	a tellurite-resistance genetic determinant was isolated from the pea blight pathogen pseudomonas syringae pathovar pisi by a shotgun strategy involving a tellurite-selective screening in escherichia coli. a 1.65 kb tellurite resistance insert was obtained and analysed. it harbours a single complete and functional orf encoding a deduced protein of 24, 445 da. the deduced aa sequence shows significant similarities with the complete human thiopurine methyltransferase enzyme, a methyltransferase fro ...	1998	9565678
is1491 from pseudomonas alcaligenes ncib 9867: characterization and distribution among pseudomonas species.	a new insertion sequence, is1491, has been cloned and sequenced. the 2489-bp is1491 was isolated from a pseudomonas alcaligenes ncib 9867 (strain p25x) 4.8-kb psti chromosomal fragment. is1491 is flanked by an imperfect inverted repeat of 23 bp and carries two overlapping open reading frames, orf1 and orf2. both orf1 and orf2 displayed homology to the ista-like and istb-like transposases encoded by the is21 family of insertion sequences, which include two is elements previously isolated from p. ...	1998	9571135
isolation and characterization of is1416 from pseudomonas glumae, a new member of the is3 family.	isolation and characterization of four different insertion sequence (is) elements from pseudomonas glumae maff 302744 through transposition into the entrapment vector pshi1063 are described. one of the elements, is1416, was further characterized. is1416 is 1322 bp long and carries 29-bp terminal inverted repeats flanked by a 3-bp direct duplication. is1416 contains three open reading frames (orfs), which are designated orfa1, orfa2, and orfb, on one strand. both dna sequence of is1416 and the de ...	1998	9571136
ptn5cat: a tn5-derived genetic element to facilitate insertion mutagenesis, promoter probing, physical mapping, cloning, and marker exchange in phytopathogenic and other gram-negative bacteria.	a tn5-derived mobile element has been constructed to identify genes and promoters related to pathogenesis and virulence in pseudomonas syringae pv. phaseolicola. to enhance the rate of mutation this tn5 derivative was constructed carrying a mutant transposase which was placed in cis to the transposable element, but just outside the inverted repeats, therefore eliminating secondary transposition and increasing the stability of the insertion. the new element also contains a promoterless cat (chlor ...	1998	9571137
antibiotic production by erwinia herbicola eh1087: its role in inhibition of erwinia amylovora and partial characterization of antibiotic biosynthesis genes.	mutants of erwinia herbicola eh1087 (ant-), which did not produce antibiotic activity against erwinia amylovora, the fire blight pathogen, were selected after tnphoa mutagenesis. in immature pear fruit ant- mutants grew at the same rate as wild-type strain eh1087 but did not suppress development of the disease caused by e. amylovora. these results indicated that antibiosis plays an important role in the suppression of disease by strain eh1087. all of the ant- mutations obtained were located in a ...	1998	9572960
ecophysiological and phylogenetic studies of nevskia ramosa in pure culture.	during the last 100 years, the neuston bacterium nevskia ramosa has been described several times. this bacterium forms conspicuous rosette-like microcolonies at the air-water interface. in this study, pure cultures of nevskia ramosa were obtained for the first time, from a bog lake (strain soe1, dsmz 11499t) and a freshwater ditch (strain ol1, dsmz 11500). the isolates showed special adaptations to life in the epineuston. they formed hydrophobic surface films with a dull appearance. n. ramosa is ...	1998	9572968
effect of bacterial distribution and activity on conjugal gene transfer on the phylloplane of the bush bean (phaseolus vulgaris).	conjugal plasmid transfer was examined on the phylloplane of bean (phaseolus vulgaris) and related to the spatial distribution pattern and metabolic activity of the bacteria. the donor (pseudomonas putida kt2442) harbored a derivative of the tol plasmid, which conferred kanamycin resistance and had the gfp gene inserted downstream of a lac promoter. a chromosomal insertion of laciq prevented expression of the gfp gene. the recipient (p. putida kt2440) had a chromosomal tetracycline resistance ma ...	1998	9572970
structures of homologous composite transposons carrying cbaabc genes from europe and north america.	is1071 is a class ii transposable element carrying a tnpa gene related to the transposase genes of the tn3 family. copies of is1071 that are conserved with more than 99% nucleotide sequence identity have been found as direct repeats flanking a remarkable variety of catabolic gene sequences worldwide. the sequences of chlorobenzoate catabolic transposons found on pbrc60 (tn5271) in niagara falls, n.y., and on pcpe3 in bologna, italy, show that these transposons were formed from highly homologous ...	1998	9572977
burkholderia cepacia produces a hemolysin that is capable of inducing apoptosis and degranulation of mammalian phagocytes.	burkholderia cepacia is an opportunistic pathogen that has become a major threat to individuals with cystic fibrosis (cf). in approximately 20% of patients, pulmonary colonization with b. cepacia leads to cepacia syndrome, a fatal fulminating pneumonia sometimes associated with septicemia. it has been reported that culture filtrates of clinically derived strains of b. cepacia are hemolytic. in this study, we have characterized a factor which contributes to this hemolytic activity and is secreted ...	1998	9573086
(methyl)ammonium transport in the nitrogen-fixing bacterium azospirillum brasilense.	an ammonium transporter of azospirillum brasilense was characterized. in contrast to most previously reported putative prokaryotic nh4+ transporter genes, a. brasilense amtb is not part of an operon with glnb or glnz which, in a. brasilense, encode nitrogen regulatory proteins pii and pz, respectively. sequence analysis predicts the presence of 12 transmembrane domains in the deduced amtb protein and classifies amtb as an integral membrane protein. nitrogen regulates the transcription of the amt ...	1998	9573149
processed virb2 is the major subunit of the promiscuous pilus of agrobacterium tumefaciens.	previous studies have implicated the obligatory requirement for the vir regulon (or "virulon") of the ti plasmid for the transfer of oncogenes from agrobacterium tumefaciens to plant cells. the machinery used in this horizontal gene transfer has been long thought to be a transformation or conjugative delivery system. based on recent protein sequence comparisons, the proteins encoded by the virb operon are strikingly similar to proteins involved in the synthesis and assembly of conjugative pili s ...	1998	9573157
nucleotide sequence and spatiotemporal expression of the vibrio cholerae viesab genes during infection.	the ivivii gene of vibrio cholerae was previously identified by a screen for genes induced during intestinal infection. in the present study, nucleotide sequence analysis revealed that ivivii is a 1,659-bp open reading frame, herein designated vieb, that is predicted to be last in a tricistronic operon (viesab). the deduced amino acid sequence of vies exhibited similarity to the sensor kinase component, and those of viea and vieb were similar to the response regulator components, respectively, o ...	1998	9573178
a race-specific insertion of transposable element is801 in pseudomonas syringae pv. phaseolicola.	the isolation and cloning of a random amplified polymorphic dna-polymerase chain reaction (rapd-pcr) band specific for pseudomonas syringae pv. phaseolicola race 1 allowed us to design a pair of primers that amplify 1.2-kb race 1-specific and 2.7-kb race 2-specific fragments, providing a rapid method for the identification of races by standard pcr methods. restriction analysis revealed identical endonuclease sites in both fragments but the race 2 fragment contains a 1.5-kb insertion, identified ...	1998	9574509
defense activation and enhanced pathogen tolerance induced by h2o2 in transgenic tobacco.	transgenic tobacco deficient in the h2o2-removing enzyme catalase (cat1as) was used as an inducible and noninvasive system to study the role of h2o2 as an activator of pathogenesis-related (pr) proteins in plants. excess h2o2 in cat1as plants was generated by simply increasing light intensities. sustained exposure of cat1as plants to excess h2o2 provoked tissue damage, stimulated salicylic acid and ethylene production, and induced the expression of acidic and basic pr proteins with a timing and ...	1998	9576968
biosynthesis and regulation of coronatine, a non-host-specific phytotoxin produced by pseudomonas syringae.	many p. syringae pathovars are known to produce low-molecular-weight, diffusible toxins in infected host plants. these phytotoxins reproduce some of the symptoms of the relevant bacterial disease and are effective at very low concentrations. phytotoxins generally enhance the virulence of the p. syringae pathovar which produces them, but are not required for pathogenesis. genes encoding phytotoxin production have been identified and cloned from several p. syringae pathovars. with the exception of ...	1998	9594652
generation of broad-spectrum disease resistance by overexpression of an essential regulatory gene in systemic acquired resistance.	the recently cloned npr1 gene of arabidopsis thaliana is a key regulator of acquired resistance responses. upon induction, npr1 expression is elevated and the npr1 protein is activated, in turn inducing expression of a battery of downstream pathogenesis-related genes. in this study, we found that npr1 confers resistance to the pathogens pseudomonas syringae and peronospora parasitica in a dosage-dependent fashion. overexpression of npr1 leads to enhanced resistance with no obvious detrimental ef ...	1998	9601001
expression of the transposase gene tnpa of tn4652 is positively affected by integration host factor.	tn4652 is a derivative of the toluene degradation transposon tn4651 that belongs to the tn3 family of transposons (m. tsuda and t. iino, mol. gen. genet. 210:270-276, 1987). we have sequenced the transposase gene tnpa of transposon tn4652 and mapped its promoter to the right end of the element. the deduced amino acid sequence of tnpa revealed 96.2% identity with the putative transposase of tn5041. homology with other tn3 family transposases was only moderate (about 20 to 24% identity), suggestin ...	1998	9603867
camalexin accumulation in arabis lyrata.	inoculation of leaves of arabis lyrata with either a bacterial pathogen pseudomonas syringae pv. maculicola strain es4326 or cochliobolus carbonum, a fungal nonpathogen of a. lyrata, resulted in the accumulation of a compound with similar chromatographic and fluorescent properties to that of camalexin (i), a phytoalexin produced by arabidopsis thaliana. a. lyrata is closely related to a. thaliana. high resolution electron impact mass spectroscopic and proton nmr analysis confirmed that the compo ...	1998	9887527
correlation of defense gene induction defects with powdery mildew susceptibility in arabidopsis enhanced disease susceptibility mutants.	we investigated the relative importance of specific arabidopsis thaliana genes in conferring resistance to bacterial versus fungal pathogens. we first developed a pathosystem involving the infection of arabidopsis accession columbia with a virulent isolate of the obligate biotrophic fungal pathogen erysiphe orontii. e. orontii elicited the accumulation of mrnas corresponding to the defense-related genes pr1, bgl2 (pr2), pr5 and gst1, but did not elicit production of the phytoalexin camalexin or ...	1998	9881167
structure of the o polysaccharide and immunochemical relationships between the lipopolysaccharides of pseudomonas syringae pathovar tomato and pathovar maculicola.	o polysaccharides (ops) of the lipopolysaccharides (lps) of pseudomonas syringae pathovar tomato gspb 483 and pathovar maculicola imv 381 were studied by 1h-nmr and 13c-nmr spectroscopy, including two-dimensional cosy, rotating-frame noe spectroscopy (roesy), and h-detected 1h,13c heteronuclear multiple-quantum coherence (hmqc) experiments. the ops from both strains were shown to be chemically identical. two structurally different types of repeating units (o repeats 1 and 2) were elucidated in e ...	1998	9874231
structural heterogeneity in the o polysaccharide of pseudomonas syringae pv. coriandricola gspb 2028 (ncppb 3780, w-43).	the o polysaccharide (ops) of the lipopolysaccharide of pseudomonas syringae pv. coriandricola gspb 2028 (ncppb 3780, w-43) was studied by smith degradation and 1h-nmr and 13c-nmr spectroscopy, including two-dimensional cosy, tocsy, noesy, and h-detected 1h,13c heteronuclear multiple-quantum coherence (hmqc) experiments. the ops was shown to consist of pentasaccharide o repeats of two types both containing four l-rhamnose and one 3-acetamido-3,6-dideoxy-d-galactose (d-fuc3nac) residue. structure ...	1998	9874239
cloning of genes by mrna differential display induced during the hypersensitive reaction of soybean after inoculation with pseudomonas syringae pv. glycinea.	soybean (glycine max [l.] merr.) cell suspension cultures (cv. williams 82) inoculated with the pathogenic bacteria pseudomonas syringae pv. glycinea respond with a hypersensitive reaction (hr) when the bacteria express the avirulence gene avra. a mrna differential display was established for this system to allow the identification of genes induced during the hr. six pcr-fragments (dd1-dd6) from the differential display analysis were identified, which are induced during the hr. database searches ...	1998	9869427
insertion specificity and trans-activation of is801.	the transposable element is801, isolated from plasmid pmmc7105 of pseudomonas syringae pv. phaseolicola, transposes in escherichia coli to plasmid targets, expressing a relatively relaxed target specificity. the target sequences are tetramers with homology with the left terminus (gaac) of the transposing unit, the alternative targets being gaac, ggac, caag, and cgac. in the areas flanking is801 in 13 different locations, no similarities other than the target tetramer were observed. the transposa ...	1998	9870703
biodegradation of phosphonomycin by rhizobium huakuii pmy1.	the biodegradation by rhizobium huakuii pmy1 of up to 10 mm phosphonomycin as a carbon, energy, and phosphorus source with accompanying p(i) release is described. this biodegradation represents a further mechanism of resistance to this antibiotic and a novel, phosphate-deregulated route for organophosphonate metabolism by rhizobium spp.	1998	9435089
homology and functional similarity of an hrp-linked pathogenicity locus, dspef, of erwinia amylovora and the avirulence locus avre of pseudomonas syringae pathovar tomato.	the "disease-specific" (dsp) region next to the hrp gene cluster of erwinia amylovora is required for pathogenicity but not for elicitation of the hypersensitive reaction. a 6.6-kb apparent operon, dspef, was found responsible for this phenotype. the operon contains genes dspe and dspf and is positively regulated by hrpl. a blast search revealed similarity in the dspe gene to a partial sequence of the avre locus of pseudomonas syringae pathovar tomato. the entire avre locus was sequenced. homolo ...	1998	9448330
accumulation of salicylic acid and 4-hydroxybenzoic acid in phloem fluids of cucumber during systemic acquired resistance is preceded by a transient increase in phenylalanine ammonia-lyase activity in petioles and stems.	cucumber (cucumis sativa) leaves infiltrated with pseudomonas syringae pv. syringae cells produced a mobile signal for systemic acquired resistance between 3 and 6 h after inoculation. the production of a mobile signal by inoculated leaves was followed by a transient increase in phenylalanine ammonia-lyase (pal) activity in the petioles of inoculated leaves and in stems above inoculated leaves; with peaks in activity at 9 and 12 h, respectively, after inoculation. in contrast, pal activity in in ...	1998	9449843
auxin production is a common feature of most pathovars of pseudomonas syringae.	we investigated indole-3-acetic acid (iaa) production by 57 pathovars of pseudomonas syringae and related species. most of those analyzed produced iaa, especially in the presence of tryptophan. eight strains produced high iaa concentrations in the absence of trp. the iaam and iaah genes of p. savastanoi pv. savastanoi were detected in a limited number of strains only, including the eight above-mentioned strains. thus, iaa synthesis in most assayed strains of p. syringae and related species does ...	1998	9450337
environmental regulation of salmonella typhi invasion-defective mutants.	salmonella typhi is the etiologic agent of human typhoid. during infection, s. typhi adheres to and invades epithelial and m cells that line the distal ileum. to survive in the human host, s. typhi must overcome numerous complex extracellular and intracellular environments. since relatively little is known about s. typhi pathogenesis, studies were initiated to identify s. typhi genes involved in the early steps of interaction with the host and to evaluate the environmental regulation of these ge ...	1998	9453627
curli fibers are highly conserved between salmonella typhimurium and escherichia coli with respect to operon structure and regulation.	mouse-virulent salmonella typhimurium strains sr-11 and atcc 14028-1s express curli fibers, thin aggregative fibers, at ambient temperature on plates as judged by western blot analysis and electron microscopy. concomitantly with curli expression, cells develop a rough and dry colony morphology and bind the dye congo red (called the rdar morphotype). cloning and characterization of the two divergently transcribed operons required for curli biogenesis, csgba(c) and csgdefg, from s. typhimurium sr- ...	1998	9457880
a cold-adapted lipase of an alaskan psychrotroph, pseudomonas sp. strain b11-1: gene cloning and enzyme purification and characterization.	a psychrotrophic bacterium producing a cold-adapted lipase upon growth at low temperatures was isolated from alaskan soil and identified as a pseudomonas strain. the lipase gene (lipp) was cloned from the strain and sequenced. the amino acid sequence deduced from the nucleotide sequence of the gene (924 bp) corresponded to a protein of 308 amino acid residues with a molecular weight of 33,714. lipp also has consensus motifs conserved in other cold-adapted lipases, i.e., lipase 2 from antarctic m ...	1998	9464382
identification of bacterial isolates obtained from intestinal contents associated with 12,000-year-old mastodon remains.	mastodon (mammut americanum) remains unearthed during excavation of ancient sediments usually consist only of skeletal material, due to postmortem decomposition of soft tissues by microorganisms. two recent excavations of skeletal remains in anoxic sediments in ohio and michigan, however, have uncovered organic masses which appear to be remnants of the small and large intestines, respectively. macrobotanical examinations of the composition of these masses revealed assemblages of plant material r ...	1998	9464403
ethylene-insensitive tobacco lacks nonhost resistance against soil-borne fungi.	enhanced ethylene production is an early response of plants to pathogen attack and has been associated with both resistance and susceptibility to disease. tobacco plants were transformed with the mutant etr1-1 gene from arabidopsis, conferring dominant ethylene insensitivity. besides lacking known ethylene responses, these transformants (tetr) did not slow growth when contacting neighboring plants, hardly expressed defense-related basic pathogenesis-related proteins, and developed spontaneous st ...	1998	9465120
a major outer membrane protein of rahnella aquatilis functions as a porin and root adhesin.	a 38-kda major outer membrane protein (omp) was isolated from the nitrogen-fixing enterobacterium rahnella aquatilis cf3. this protein exists as a stable trimer in the presence of 2% sodium dodecyl sulfate at temperatures below 60 degrees c. single channel experiments showed that this major omp of r. aquatilis cf3 is able to form pores in the planar lipid membrane. two oligonucleotides encoding the n-terminal portion of the 38-kda omp and c-terminal portion of ompc were used to amplify the 38-kd ...	1998	9473046
phosphorylation-independent activity of the response regulators algb and algr in promoting alginate biosynthesis in mucoid pseudomonas aeruginosa.	overproduction of the capsular polysaccharide alginate appears to confer a selective advantage for pseudomonas aeruginosa in the lungs of cystic fibrosis patients. the regulators algb and algr, which are both required as positive activators in alginate overproduction, have homology with the regulator class of two-component environmental responsive proteins which coordinate gene expression through signal transduction mechanisms. signal transduction in this class of proteins generally occurs via a ...	1998	9473053
the synthesis of tabtoxin peptide bond in pseudomonas syringae pv. tabaci.		1998	10047897
chlorosis-inducing products from pseudomonas syringae pathovars: new n-coronafacoyl compounds.	liquid cultures of pseudomonas syringae pv. tomato strains that also produced the phytotoxin coronatine, were found to have a new chlorosis-inducing activity, not previously described. bioassay-guided fractionation and hplc analysis revealed two new peaks that were chlorosis-inducing on leaves of bean plants. mass spectrometry and nmr analyses of the compounds led to the derivation of their structures as coronafacoyl-l-serine and coronafacoyl-l-threonine, respectively. the amino acid c-2 configu ...	1998	11711068
identification of tomato leaf factors that activate toxin gene expression in pseudomonas syringae pv. tomato dc3000.	abstract coronatine is a non-host-specific chlorosis-inducing phytotoxin produced by the tomato and crucifer pathogen pseudomonas syringae pv. tomato dc3000. how the chromosomal gene cluster controlling toxin synthesis in this strain is regulated in planta is unknown. ice nucleation-active cor:inaz marker-exchange derivatives of strain dc3000 were used to determine coronatine gene expression in various host and nonhost plants and in a minimal medium supplemented with selected tomato plant consti ...	1998	18944822
occurrence of indole-3-acetic acid-producing bacteria on pear trees and their association with fruit russet.	abstract a relatively high percentage of epiphytic bacteria on pear leaf and fruit surfaces had the ability to produce indole-3-acetic acid (iaa) in culture media supplemented with tryptophan. while over 50% of the strains produced at least small amounts of iaa in culture, about 25% of the strains exhibited high iaa production as evidenced by both colorimetric and high-performance liquid chromatography analysis of culture supernatants. a majority of the strains that produced high amounts of iaa ...	1998	18944847
mixtures of plant growth-promoting rhizobacteria enhance biological control of multiple cucumber pathogens.	abstract plant growth-promoting rhizobacteria (pgpr) strains inr7 (bacillus pumilus), gb03 (bacillus subtilis), and me1 (curtobacterium flaccumfaciens) were tested singly and in combinations for biological control against multiple cucumber pathogens. investigations under greenhouse conditions were conducted with three cucumber pathogens-colletotrichum orbiculare (causing anthracnose), pseudomonas syringae pv. lachrymans (causing angular leaf spot), and erwinia tracheiphila(causing cucurbit wilt ...	1998	18944848
a conjugative plasmid carrying the efe gene for the ethylene-forming enzyme isolated from pseudomonas syringae pv. glycinea.	abstract previous work suggested that the efe gene encoding the ethylene-forming enzyme was present in the plasmids of three pathovars of pseudomonas syringae including glycinea, phaseolicola (kudzu strains), and cannabina. however, no direct evidence to support this assumption had been presented. in the current study, we isolated the conjugative plasmid harboring the efe gene (ethylene plasmid) designated peth2 from p. syringae pv. glycinea maff301683. peth2 was detected by southern blot hybrid ...	1998	18944855
description of the bacterium causing blight of leek as pseudomonas syringae pv. porri (pv. nov.).	abstract forty bacterial strains isolated from leek blight (allium porrum) in france and other countries were studied by conventional biochemical methods, serological reactions, numerical taxonomy, dna-dna hybridization, and ice nucleation activity, as well as by pathogenicity on leek and other host plants. they were compared with reference strains of pseudomonas, mainly pathotype strains of p. syringae pathovars and strains of p. syringae pv. syringae isolated from various host plants including ...	1998	18944892
compost and compost water extract-induced systemic acquired resistance in cucumber and arabidopsis.	abstract a biocontrol agent-fortified compost mix, suppressive to several diseases caused by soilborne plant pathogens, induced systemic acquired resistance (sar) in cucumber against anthracnose caused by colletotrichum orbiculare and in arabidopsis against bacterial speck caused by pseudomonas syringae pv. maculicola kd4326. a peat mix conducive to soilborne diseases did not induce sar. the population size of p. syringae pv. maculicola kd4326 was significantly lower in leaves of arabidopsis pla ...	1998	18944926
bacterial apical necrosis of mango in southern spain: a disease caused by pseudomonas syringae pv. syringae.	abstract a necrotic bacterial disease of mango trees (mangifera indica) in spain affecting buds, leaves, and stems is described for the first time. necrosis of flower and vegetative buds on commercial trees during winter dormancy was the most destructive symptom of the disease. the apical necrosis is caused by pseudomonas syringae, which was always isolated from mango trees with disease symptoms. of 95 bacterial strains isolated from symptomatic tissues and characterized from 1992 to 1997, over ...	1998	18944933
glucosylation of salicylic acid in nicotiana tabacum cv. xanthi-nc.	abstract salicylic acid (sa) is a key regulatory component of disease resistance in plants. in tobacco mosaic virus (tmv)-inoculated tobacco (nicotiana tabacum cv. xanthi-nc nn genotype), newly synthesized sa is converted primarily to sa 2-o-beta-d-glucoside (sag) and glucosyl salicylate (gs), a relatively minor metabolite. similar patterns in the formation of gs and sag were observed in tobacco inoculated with pseudomonas syringae pv. phaseolicola, suggesting the accumulation of two glucosylate ...	1998	18944942
changes in salicylic acid and antioxidants during induced thermotolerance in mustard seedlings	heat-acclimation or salicylic acid (sa) treatments were previously shown to induce thermotolerance in mustard (sinapis alba l.) seedlings from 1.5 to 4 h after treatment. in the present study we investigated changes in endogenous sa and antioxidants in relation to induced thermotolerance. thirty minutes into a 1-h heat-acclimation treatment glucosylated sa had increased 5.5-fold and then declined during the next 6 h. increases in free sa were smaller (2-fold) but significant. changes in antioxid ...	1998	9847121
biosynthesis of camalexin from tryptophan pathway intermediates in cell-suspension cultures of arabidopsis.	camalexin (3-thiazol-2'-yl-indole) is the principal phytoalexin that accumulates in arabidopsis after infection by fungi or bacteria. camalexin accumulation was detectable in arabidopsis cell-suspension cultures 3 to 5 h after inoculation with cochliobolus carbonum (race 1), and then increased rapidly from 7 to 24 h after inoculation. levels of radioactivity incorporated into camalexin during a 1.5-h pulse labeling with [14c]anthranilate also increased with time after fungal inoculation. the lev ...	1998	9847113
ozone sensitivity in hybrid poplar is correlated with a lack of defense-gene activation	ozone is a major gaseous pollutant thought to contribute to forest decline. although the physiological and morphological responses of forest trees to ozone have been well characterized, little is known about the molecular basis for these responses. our studies compared the response to ozone of ozone-sensitive and ozone-tolerant clones of hybrid poplar (populus maximowizii x populus trichocarpa) at the physiological and molecular levels. gas-exchange analyses demonstrated clear differences betwee ...	1998	9847098
the molecular mechanisms responsible for resistance in plant-pathogen interactions of the gene-for-gene type function more broadly than previously imagined.		1998	9707538
the biosynthesis of salicylic acid in potato plants	spraying potato (solanum tuberosum l.) leaves with arachidonic acid (aa) at 1500 &mgr;g ml-1 led to a rapid local synthesis of salicylic acid (sa) and accumulation of a sa conjugate, which was shown to be 2-o-beta-glucopyranosylsalicylic acid. radiolabeling studies with untreated leaves showed that sa was synthesized from phenylalanine and that both cinnamic and benzoic acid were intermediates in the biosynthesis pathway. using radiolabeled phenylalanine as a precursor, the specific activity of ...	1998	9662552
systemin potentiates the oxidative burst in cultured tomato cells	plants that have been wounded by insects or other herbivores may be more susceptible to infection by adventitious microbes. wound-induced signal molecules, which serve to induce responses in the plant that retard further feeding, might also act to prepare a plant for possible pathogen attack. we have examined the effect of a wound-generated systemic messenger (systemin) on a pathogen-stimulated defense-response marker, the oxidative burst. we observed that neither systemin nor its inactive analo ...	1998	9662546
parallel changes in h2o2 and catalase during thermotolerance induced by salicylic acid or heat acclimation in mustard seedlings	spraying mustard (sinapis alba l.) seedlings with salicylic acid (sa) solutions between 10 and 500 &mgr;m significantly improved their tolerance to a subsequent heat shock at 55 degreesc for 1.5 h. the effects of sa were concentration dependent, with higher concentrations failing to induce thermotolerance. the time course of thermotolerance induced by 100 &mgr;m sa was similar to that obtained with seedlings acclimated at 45 degreesc for 1 h. we examined the hypothesis that induced thermotoleran ...	1998	9536052
directed changes in the number of double-stranded rna genomic segments in bacteriophage phi6.	bacteriophage phi6 has a genome of three segments of double-stranded rna. the segments are designated s, m, and l. each segment has a unique packaging site, pac, near the 5' end of the plus strand. the plus strands of the segments are normally packaged in the order s, m, l. chimeras of segment m and s in which segment m is at the 5' end of the plus strand can be stably incorporated into the virion; however, an independent segment s must be included along with normal segment l, even if it contain ...	1998	9520468
characterization of a 34-kda soybean binding protein for the syringolide elicitors.	syringolides are water-soluble, low-molecular-weight elicitors that trigger defense responses in soybean cultivars carrying the rpg4 disease-resistance gene but not in rpg4 cultivars. 125i-syringolide 1 previously was shown to bind to a soluble protein(s) in extracts from soybean leaves. a 34-kda protein that accounted for 125i-syringolide 1 binding activity was isolated with a syringolide affinity-gel column. partial sequences of internal peptides of the 34-kda protein were identical to p34, a ...	1998	9501258
differential expression of a novel gene in response to coronatine, methyl jasmonate, and wounding in the coi1 mutant of arabidopsis.	coronatine is a phytotoxin produced by some plant-pathogenic bacteria. it has been shown that coronatine mimics the action of methyl jasmonate (meja) in plants. meja is a plant-signaling molecule involved in stress responses such as wounding and pathogen attack. in arabidopsis thaliana, meja is essential for pollen grain development. the coi1 (for coronatine-insensitive) mutant of arabidopsis, which is insensitive to coronatine and meja, produces sterile male flowers and shows an altered respons ...	1998	9501136
relationship between co2 assimilation, photosynthetic electron transport, and active o2 metabolism in leaves of maize in the field during periods of low temperature	measurements of the quantum efficiencies of photosynthetic electron transport through photosystem ii (phipsii) and co2 assimilation (phico2) were made simultaneously on leaves of maize (zea mays) crops in the united kingdom during the early growing season, when chilling conditions were experienced. the activities of a range of enzymes involved with scavenging active o2 species and the levels of key antioxidants were also measured. when leaves were exposed to low temperatures during development, ...	1998	9490760
rapid reorganization of resistance gene homologues in cereal genomes.	we used conserved domains in the major class (nucleotide binding site plus leucine-rich repeat) of dicot resistance (r) genes to isolate related gene fragments via pcr from the monocot species rice and barley. peptide sequence comparison of dicot r genes and monocot r-like genes revealed shared motifs but provided no evidence for a monocot-specific signature. mapping of these genes in rice and barley showed linkage to genetically characterized r genes and revealed the existence of mixed clusters ...	1998	9419382
replication and control of circular bacterial plasmids.	an essential feature of bacterial plasmids is their ability to replicate as autonomous genetic elements in a controlled way within the host. therefore, they can be used to explore the mechanisms involved in dna replication and to analyze the different strategies that couple dna replication to other critical events in the cell cycle. in this review, we focus on replication and its control in circular plasmids. plasmid replication can be conveniently divided into three stages: initiation, elongati ...	1998	9618448
biology of moderately halophilic aerobic bacteria.	the moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. the property of halophilism is widespread within the bacterial domain. bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. complex mechanisms of ...	1998	9618450
superoxide dismutase in arabidopsis: an eclectic enzyme family with disparate regulation and protein localization.	a number of environmental stresses can lead to enhanced production of superoxide within plant tissues, and plants are believed to rely on the enzyme superoxide dismutase (sod) to detoxify this reactive oxygen species. we have identified seven cdnas and genes for sod in arabidopsis. these consist of three cuznsods (csd1, csd2, and csd3), three fesods (fsd1, fsd2, and fsd3), and one mnsod (msd1). the chromosomal location of these seven sod genes has been established. to study this enzyme family, a ...	1998	9765550
insertion sequences.	insertion sequences (iss) constitute an important component of most bacterial genomes. over 500 individual iss have been described in the literature to date, and many more are being discovered in the ongoing prokaryotic and eukaryotic genome-sequencing projects. the last 10 years have also seen some striking advances in our understanding of the transposition process itself. not least of these has been the development of various in vitro transposition systems for both prokaryotic and eukaryotic e ...	1998	9729608
organization of an arabidopsis thaliana gene cluster on chromosome 4 including the rps2 gene, in the brassica nigra genome.	genetic and physical maps, consisting of a large number of dna markers for arabidopsis thaliana chromosomes, represent excellent tools to determine the organization of related genomes such as those of brassica. in this paper we report the chromosomal localization and physical analysis by pulsed-field gel electrophoresis (pfge) of a well-defined gene complex of a. thaliana in the brassica nigra genome (b genome n=8). this complex is approximately 30 kb in length in a. thaliana and contains a clus ...	1998	24710886
syntheses and potato tuber-inducing activity of coronafacic acid analogues.	coronafacic acid (1) is an acid component of coronatine, and has been isolated from several pathovars of pseudomonas syringae. syntheses of c6-non- and c6-alkyl-substituted analogues of 1 were accomplished via intramolecular 1,6-conjugate addition as the key step. among them, 1 and four c6-alkyl-substituted analogues exhibited potato tuber-inducing activity, but the c6-non-substituted analogue did not. it was revealed that a certain length of the c6-alkyl group was necessary to exhibit activity.	1998	27392555
specificity of induced resistance in the tomato, lycopersicon esculentum.	specificity in the induced responses of tomato foliage to arthropod herbivores was investigated. we distinguished between two aspects of specificity: specificity of effect (the range of organisms affected by a given induced response), and specificity of elicitation (ability of the plant to generate distinct chemical responses to different damage types). specificity of effect was investigated by examining the effect of restricted feeding by helicoverpa zea on the resistance of tomato plants to an ...	1997	28307296
elicitor-stimulated ion fluxes and o2- from the oxidative burst are essential components in triggering defense gene activation and phytoalexin synthesis in parsley.	fungal elicitor stimulates a multicomponent defense response in cultured parsley cells (petroselinum crispum). early elements of this receptor-mediated response are ion fluxes across the plasma membrane and the production of reactive oxygen species (ros), sequentially followed by defense gene activation and phytoalexin accumulation. omission of ca2+ from the culture medium or inhibition of elicitor-stimulated ion fluxes by ion channel blockers prevented the latter three reactions, all of which w ...	1997	9114072
detection of new ethylene-producing bacteria, pseudomonas syringae pvs. cannabina and sesami, by pcr amplification of genes for the ethylene-forming enzyme.	abstract strains of pseudomonas syringae (78 strains and 43 pathovars) and other strains (79) of plant and insect origin were examined for the presence of the ethylene-forming enzyme gene (efe) by polymerase chain reaction (pcr) assay. the sequence of the efe gene of p. syringae pv. phaseolicola pk2 was used to design two primer sets for amplification of the gene. in addition to p.syringae pv. phaseolicola (the "kudzu strain") and p.syringae pv. glycinea, which were efficient ethylene producers, ...	1997	18945017
expression of an engineered cecropin gene cassette in transgenic tobacco plants confers disease resistance to pseudomonas syringae pv. tabaci.	abstract a chimeric gene fusion cassette, consisting of a secretory sequence from barley alpha-amylase joined to a modified cecropin (mb39) coding sequence and placed under control of the promoter and terminator from the potato proteinase inhibitor ii (piii) gene, was introduced into tobacco by agrobacterium-mediated transformation. transgenic and control plants reacted differently when inoculated with tobacco wildfire pathogen pseudomonas syringae pv. tabaci at various cell concentrations. with ...	1997	18945103
effects of specific expression of iaal gene in tobacco tapetum on pollen embryogenesis.	the indoleacetic-acid-lysine synthetase (iaal) gene from pseudomonas syringae subsp. savastanoi was fused to tobacco tapetum-specific expression promoter ta29, and introduced into tobacco. the expression pattern of this chimeric gene was studied, and the endogenous indoleacetic acid (iaa) levels in different organs were assayed. the results demonstrated that ta29 promoter was only able to direct the specific expression of iaal gene in transgenic tobacco anther, and resulted in the decrease of en ...	1997	18762878
specific binding of the syringolide elicitors to a soluble protein fraction from soybean leaves.	syringolides are glycolipid elicitors produced by gram-negative bacteria expressing pseudomonas syringae avirulence gene d. the syringolides mediate gene-for-gene complementarity, inducing the hypersensitive response only in soybean plants carrying the rpg4 disease resistance gene. a site(s) for 125i-syringolide 1 was detected in the soluble protein fraction from soybean leaves, but no evidence for ligand-specific binding to the microsomal fraction was obtained. the kd value for syringolide 1 bi ...	1997	12237390
observations of ice nucleation and propagation in plants using infrared video thermography.	we evaluated the use of infrared (ir) video thermography to observe directly ice nucleation and propagation in plants. an imaging radiometer with an hgcdte long-wave (8-12 [mu]m) detector was utilized to image the thermal response of plants during freezing. ir images were analyzed in real time and recorded on videotape. information on the videotape was subsequently accessed and analyzed utilizing ir image analysis software. freezing of water droplets as small as 0.5 [mu]l was clearly detectable ...	1997	12223611
gene-expression patterns and levels of jasmonic acid in rice treated with the resistance inducer 2,6-dichloroisonicotinic acid.	acquired disease resistance can be induced in rice (oryza sativa) by a number of synthetic or natural compounds, but the molecular mechanisms behind the phenomenon are poorly understood. one of the synthetic inducers of resistance, 2,6-dichloroisonicotinic acid (ina), efficiently protected rice leaves from infection by the rice blast fungus magnaporthe grisea (hebert) barr. a comparison of gene-expression patterns in plants treated with ina versus plants inoculated with the compatible pathogen m ...	1997	12223792
salicylic acid is needed in hypersensitive cell death in soybean but does not act as a catalase inhibitor.	the function of salicylic acid (sa) in hypersensitive cell death was studied in a soybean (glycine max)-pseudomonas syringae pv glycinea system. the infection of cell cultures with bacteria leads to a hypersensitive reaction (hr), which is dependent on an appropriate avirulence gene and on low concentrations of sa. the requirement for sa is essential for a process shortly before the onset of the hr-caused cell death 5 to 6 h after infection with bacteria. sa given 10 to 12 h after infection or p ...	1997	12223807