Publications

deficiency in phytoalexin production causes enhanced susceptibility of arabidopsis thaliana to the fungus alternaria brassicicola.	the phytoalexin-deficient arabidopsis mutant pad3-1, which is affected in the production of the indole-type phytoalexin camalexin, has previously been shown not to display altered susceptibility to either the bacterium pseudomonas syringae (glazebrook & ausubel 1994; proc. natl. acad. sci. usa, 91: 8955-8959) or the biotrophic fungi peronospora parasitica (glazebrook et al. 1997; genetics, 146: 381-392) and erysiphe orontii (reuber et al. 1998; plant j. 16: 473-485). we now show that this mutant ...	1999	10476063
genetics of o-antigen biosynthesis in pseudomonas aeruginosa.	pathogenic bacteria produce an elaborate assortment of extracellular and cell-associated bacterial products that enable colonization and establishment of infection within a host. lipopolysaccharide (lps) molecules are cell surface factors that are typically known for their protective role against serum-mediated lysis and their endotoxic properties. the most heterogeneous portion of lps is the o antigen or o polysaccharide, and it is this region which confers serum resistance to the organism. pse ...	1999	10477307
dnak and the heat stress response of pseudomonas syringae pv. glycinea.	the dnak gene from pseudomonas syringae pv. glycinea pg4180 was cloned and sequenced. the dnak coding region was 1,917 bp and contained a putative sigma 32 heat shock promoter 86 bp upstream of the translational start site. grpe, another heat shock gene, was found immediately upstream of the putative dnak promoter. the predicted amino acid sequence of dnak showed relatedness to the atpase and substrate binding domains commonly found in heat shock proteins, as well as the highly conserved signatu ...	1999	10478477
determining chemotactic responses by two subsurface microaerophiles using a simplified capillary assay method.	a simplified capillary chemotaxis assay utilizing a hypodermic needle, syringe, and disposable pipette tip was developed to measure bacterial tactic responses. the method was applied to two strains of subsurface microaerophilic bacteria. this method was more convenient than the adler method and required less practice. isolate vt10 was a strain of pseudomonas syringae, which was isolated from the shallow subsurface. it was chemotactically attracted toward dextrose, glycerol, and phenol, which cou ...	1999	10480269
trac of incn plasmid pkm101 associates with membranes and extracellular high-molecular-weight structures in escherichia coli.	conjugative transfer of incn plasmid pkm101 is mediated by the trai-traii region-encoded transfer machinery components. similar to the case for the related agrobacterium tumefaciens t-complex transfer apparatus, this machinery is needed for assembly of pili to initiate cell-to-cell contact preceding dna transfer. biochemical and cell biological experiments presented here show extracellular localization of trac, as suggested by extracellular complementation of trac-deficient bacteria by helper ce ...	1999	10482495
pathways of assimilative sulfur metabolism in pseudomonas putida.	cysteine and methionine biosynthesis was studied in pseudomonas putida s-313 and pseudomonas aeruginosa pao1. both these organisms used direct sulfhydrylation of o-succinylhomoserine for the synthesis of methionine but also contained substantial levels of o-acetylserine sulfhydrylase (cysteine synthase) activity. the enzymes of the transsulfuration pathway (cystathionine gamma-synthase and cystathionine beta-lyase) were expressed at low levels in both pseudomonads but were strongly upregulated d ...	1999	10482527
hydrogen peroxide from the oxidative burst is neither necessary nor sufficient for hypersensitive cell death induction, phenylalanine ammonia lyase stimulation, salicylic acid accumulation, or scopoletin consumption in cultured tobacco cells treated with elicitin.	h(2)o(2) from the oxidative burst, cell death, and defense responses such as the production of phenylalanine ammonia lyase (pal), salicylic acid (sa), and scopoletin were analyzed in cultured tobacco (nicotiana tabacum) cells treated with three proteinaceous elicitors: two elicitins (alpha-megaspermin and beta-megaspermin) and one glycoprotein. these three proteins have been isolated from phytophthora megasperma h20 and have been previously shown to be equally efficient in inducing a hypersensit ...	1999	10482671
the generation of active oxygen species differs in tobacco and grapevine mesophyll protoplasts.	our previous results have shown that oxidative stress may reduce the regeneration potential of protoplasts, but only protoplasts that are able to supply extracellularly h(2)o(2) can actually divide (c.i. siminis, a.k. kanellis, k.a. roubelakis-angelakis [1993] physiol plant 87: 263-270; c.i. siminis, a.k. kanellis, k.a. roubelakis-angelakis [1994] plant physiol 1105: 1375-1383; a. de marco, k.a. roubelakis-angelakis [1996a] plant physiol 110: 137-145; a. de marco, k.a. roubelakis-angelakis [1996 ...	1999	10482675
identification of a pathogenicity island, which contains genes for virulence and avirulence, on a large native plasmid in the bean pathogen pseudomonas syringae pathovar phaseolicola.	the 154-kb plasmid was cured from race 7 strain 1449b of the phytopathogen pseudomonas syringae pv. phaseolicola (pph). cured strains lost virulence toward bean, causing the hypersensitive reaction in previously susceptible cultivars. restoration of virulence was achieved by complementation with cosmid clones spanning a 30-kb region of the plasmid that contained previously identified avirulence (avr) genes avrd, avrpphc, and avrpphf. single transposon insertions at multiple sites (including one ...	1999	10485919
the gain-of-function arabidopsis acd6 mutant reveals novel regulation and function of the salicylic acid signaling pathway in controlling cell death, defenses, and cell growth.	we isolated a dominant gain-of-function arabidopsis mutant, accelerated cell death 6 (acd6), with elevated defenses, patches of dead and enlarged cells, reduced stature, and increased resistance to pseudomonas syringae. the acd6-conferred phenotypes are suppressed by removing a key signaling molecule, salicylic acid (sa), by using the nahg transgene, which encodes sa hydroxylase. this suppression includes phenotypes that are not induced by application of sa to wild-type plants, indicating that s ...	1999	10488236
a new peroxidase cdna from white clover: its characterization and expression in root tissue challenged with homologous rhizobia, heterologous rhizobia, or pseudomonas syringae.	temporal reverse transcription-polymerase chain reaction (rt-pcr) expression analyses were performed on trprx2, a new white clover peroxidase, with roots challenged with homologous rhizobia, heterologous rhizobia, and a pathogen, pseudomonas syringae. low levels of trprx2 expression were evident in all rhizobial treatments but in p.syringae-treated clover background expression was dramatically reduced within 1 h and was undetectable in treatments inoculated for more than 3 h. spraying 4 mm salic ...	1999	10494634
genomic subtractive hybridization and selective capture of transcribed sequences identify a novel salmonella typhimurium fimbrial operon and putative transcriptional regulator that are absent from the salmonella typhi genome.	salmonella typhi, the etiologic agent of typhoid fever, is adapted to the human host and unable to infect nonprimate species. the genetic basis for host specificity in s. typhi is unknown. the avirulence of s. typhi in animal hosts may result from a lack of genes present in the broad-host-range pathogen salmonella typhimurium. genomic subtractive hybridization was successfully employed to isolate s. typhimurium genomic sequences which are absent from the s. typhi genome. these genomic subtracted ...	1999	10496884
differential transcription of the tcpph operon confers biotype-specific control of the vibrio cholerae toxr virulence regulon.	epidemic strains of vibrio cholerae o1 are divided into two biotypes, classical and el tor. in both biotypes, regulation of virulence gene expression depends on a cascade in which toxr activates expression of toxt, and toxt activates expression of cholera toxin and other virulence genes. in the classical biotype, maximal expression of this toxr regulon in vitro occurs at 30 degrees c at ph 6.5 (toxr-inducing conditions), whereas in the el tor biotype, production of these virulence genes only occ ...	1999	10496885
expression of the soxr gene of pseudomonas aeruginosa is inducible during infection of burn wounds in mice and is required to cause efficient bacteremia.	burn wounds are prone to infection by pseudomonas aeruginosa, which is an opportunistic pathogen causing various human diseases. during infection, the bacterium senses environmental changes and regulates the expression of genes appropriate for survival. a purine-auxotrophic mutant of p. aeruginosa was unable to replicate efficiently on burn wounds, suggesting that burn wounds are purine-deficient environments. an in vivo expression technology based on purek gene expression was applied to the bur ...	1999	10496912
antifungal activities of antineoplastic agents: saccharomyces cerevisiae as a model system to study drug action.	recent evolutionary studies reveal that microorganisms including yeasts and fungi are more closely related to mammals than was previously appreciated. possibly as a consequence, many natural-product toxins that have antimicrobial activity are also toxic to mammalian cells. while this makes it difficult to discover antifungal agents without toxic side effects, it also has enabled detailed studies of drug action in simple genetic model systems. we review here studies on the antifungal actions of a ...	1999	10515904
cloning and sequence analysis of two pseudomonas flavoprotein xenobiotic reductases.	the genes encoding flavin mononucleotide-containing oxidoreductases, designated xenobiotic reductases, from pseudomonas putida ii-b and p. fluorescens i-c that removed nitrite from nitroglycerin (ng) by cleavage of the nitroester bond were cloned, sequenced, and characterized. the p. putida gene, xena, encodes a 39,702-da monomeric, nad(p)h-dependent flavoprotein that removes either the terminal or central nitro groups from ng and that reduces 2-cyclohexen-1-one but did not readily reduce 2,4,6- ...	1999	10515912
identification of a locus in arabidopsis controlling both the expression of rhizobacteria-mediated induced systemic resistance (isr) and basal resistance against pseudomonas syringae pv. tomato.	selected nonpathogenic rhizobacteria with biological disease control activity are able to elicit an induced systemic resistance (isr) response that is phenotypically similar to pathogen-induced systemic acquired resistance (sar). ten ecotypes of arabidopsis thaliana were screened for their potential to express rhizobacteria-mediated isr and pathogen-induced sar against the leaf pathogen pseudomonas syringae pv. tomato dc3000 (pst). all ecotypes expressed sar. however, of the 10 ecotypes tested, ...	1999	10517031
the transcriptional activator corr is involved in biosynthesis of the phytotoxin coronatine and binds to the cmaabt promoter region in a temperature-dependent manner.	a modified two-component regulatory system consisting of the histidine protein kinase cors and two highly homologous response regulators, corr and corp, controls biosynthesis of the polyketide phytotoxin coronatine (cor) by pseudomonas syringae pv. glycinea pg4180 in a temperature-dependent manner. cor synthesis is maximal at 18 degrees c but does not occur at 28 degrees c. fusions of corr and corp to the maltose-binding protein (mbp) were overproduced in escherichia coli and p. syringae pg4180, ...	1999	10517320
[vascular bundle specific expression of iaal gene affects the generation frequencies of transgenic tobacco].	a vascular bundles specific expressing vector pbal1 with a promoter aq630 from rice phenylalanine ammonialyase gene and a gene encoding indoleacetic-lysine synthytase from pseudomonas syringae subsp. savastanoi was constructed. affirmed by southern blotting and rtpcr analysis, the aq630-iaal transgenic plants show increasing shoots-regeneration frequency of young stem explants on hormone-free 1/2 ms medium and lower sensibility to iaa when roots were induced from the root explants on the media c ...	1999	12548796
long-term reduction of cold hardiness following ingestion of ice-nucleating bacteria in the colorado potato beetle, leptinotarsa decemlineata.	we investigated the effect of ingestion of ice-nucleating bacteria on the supercooling capacity and cold hardiness of the colorado potato beetle (leptinotarsa decemlineata say), a freeze-intolerant species that overwinters as adults in shallow, terrestrial burrows. ingestion of ice-nucleating bacteria (enterobacter agglomerans, pseudomonas fluorescens, pseudomonas putida, pseudomonas syringae), fed on slices of potato tuber, caused an abrupt decrease in supercooling capacity. no change occurred ...	1998	12770317
pcr detection of cyclic lipodepsinonapeptide-producing pseudomonas syringae pv. syringae and similarity of strains.	many strains of pseudomonas syringae pv. syringae produce one of four classes of small cyclic lipodepsinonapeptides: syringomycins, syringostatins, syringotoxins, or pseudomycins. these metabolites are phytotoxic and growth inhibitory against a broad spectrum of fungi. their production is dependent upon the expression of conserved biosynthesis and export genes syrb and syrd, respectively. pcr and oligonucleotide primers specific for a 752-bp fragment of syrb were used to identify cyclic lipodeps ...	1998	16349482
identification of hydrocarbon-degrading bacteria in soil by reverse sample genome probing.	bacteria with limited genomic cross-hybridization were isolated from soil contaminated with c5+, a mixture of hydrocarbons, and identified by partial 16s rrna sequencing. filters containing denatured genomic dnas were used in a reverse sample genome probe (rsgp) procedure for analysis of the effect of an easily degradable compound (toluene) and a highly recalcitrant compound (dicyclopentadiene [dcpd]) on community composition. hybridization with labeled total-community dna isolated from soil exp ...	1998	16349504
comparison of randomly amplified polymorphic dna with amplified fragment length polymorphism to assess genetic diversity and genetic relatedness within genospecies iii of pseudomonas syringae.	recently, dna pairing analyses showed that pseudomonas syringae pv. tomato and related pathovars, including p. syringae pv. maculicola, form a genomic species (pseudomonas tomato) (l. gardan, h. l. shafik, and p. a. d. grimont, p. 445-448, in k. rudolph, t. j. burr, j. w. mansfield, d. stead, a. vivian, and j. von kietzell, ed., pseudomonas syringae pathovars and related pathogens, 1997). the genetic diversity of 23 strains belonging to this genomic species and 4 outgroup strains was analyzed wi ...	1998	16349533
spatial and temporal deposition of adhesive extracellular polysaccharide capsule and fimbriae by hyphomonas strain mhs-3.	hyphomonas strain mhs-3, a member of a genus of primary colonizers of surfaces immersed in marine water, synthesizes two structures that mediate adhesion to solid substrata, namely, capsular exopolysaccharide and fimbriae. specific stains, gold-labelled lectins, and monoclonal antibodies, along with transmission electron microscopy of synchronized populations, revealed that both structures are polarly and temporally expressed. the timed synthesis and placement of the fimbriae and capsule correla ...	1998	16349537
isolation of new arabidopsis mutants with enhanced disease susceptibility to pseudomonas syringae by direct screening.	to identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for arabidopsis mutants in the accession columbia (carrying the transgene bgl2-gus) that display enhanced disease susceptibility to the virulent bacterial pathogen pseudomonas syringae pv. maculicola (psm) es4326. among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described ...	1998	9611172
the hrpc and hrpn operons of erwinia chrysanthemi ec16 are flanked by plca and homologs of hemolysin/adhesin genes and accompanying activator/transporter genes.	the hrpc operon of erwinia chrysanthemi ec16 encodes five genes conserved in erwinia amylovora and pseudomonas syringae. mutagenesis indicated that hrcc is required for elicitation of the hypersensitive reaction in tobacco leaves. the unexpected presence of plca and homologs of hemolysin/activator genes in the regions flanking the hrcc and hrpn operons is reported.	1998	9612954
the myristylation motif of pto is not required for disease resistance.	the tomato pto kinase confers resistance to bacterial speck disease caused by strains of pseudomonas syringae pv. tomato that express the avirulence gene avrpto. pto contains a putative myristylation site at its amino terminus that was hypothesized to play a role in localizing pto in the plant cell. site-directed mutagenesis was used to change the invariant glycine residue in the myristylation motif to an alanine. transgenes encoding the mutant pto(g2a) and wild-type pto were placed behind the c ...	1998	9612955
type iii protein secretion systems in bacterial pathogens of animals and plants.	various gram-negative animal and plant pathogens use a novel, sec-independent protein secretion system as a basic virulence mechanism. it is becoming increasingly clear that these so-called type iii secretion systems inject (translocate) proteins into the cytosol of eukaryotic cells, where the translocated proteins facilitate bacterial pathogenesis by specifically interfering with host cell signal transduction and other cellular processes. accordingly, some type iii secretion systems are activat ...	1998	9618447
surface display of zymomonas mobilis levansucrase by using the ice-nucleation protein of pseudomonas syringae.	the ice-nucleation protein (inp) is a glycosyl phosphatidylinositol-anchored outer membrane protein found in some gram-negative bacteria. using pseudomonas syringae inp as an anchoring motif, we investigated the functional display of a foreign protein, zymomonas mobilis levansucrase (levu), on the surface of escherichia coli. the cells expressing inp-levu were found to retain both the ice-nucleation and whole-cell levansucrase enzyme activities, indicating the functional expression of inp-levu h ...	1998	9624691
identification of the gene encoding the tryptophan synthase beta-subunit from chlamydomonas reinhardtii.	we report the isolation of a chlamydomonas reinhardtii cdna that encodes the beta-subunit of tryptophan synthase (tsb). this cdna was cloned by functional complementation of a trp-operon-deleted strain of escherichia coli. hybridization analysis indicated that the gene exists in a single copy. the predicted amino acid sequence showed the greatest identity to tsb polypeptides from other photosynthetic organisms. with the goal of identifying mutations in the gene encoding this enzyme, we isolated ...	1998	9625698
use of a new tetrazolium-based assay to study the production of superoxide radicals by tobacco cell cultures challenged with avirulent zoospores of phytophthora parasitica var nicotianae	the relationship between the production of reactive oxygen species and the hypersensitive response (hr) of tobacco (nicotiana tabacum l. ) toward an incompatible race of the oomycete phytophthora parasitica var nicotianae has been investigated. a new assay for superoxide radical (o2-) production based on reduction of the tetrazolium dye sodium,3'-(1-[phenylamino-carbonyl]-3, 4-tetrazolium)-bis(4-methoxy-6-nitro) benzene-sulfonic acid hydrate (xtt) has enabled the quantitative estimation of perhy ...	1998	9625702
correlation between binding affinity and necrosis-inducing activity of mutant avr9 peptide elicitors.	the race-specific peptide elicitor avr9 of the fungus cladosporium fulvum induces a hypersensitive response only in tomato (lycopersicon esculentum) plants carrying the complementary resistance gene cf-9 (moneymaker-cf9). a binding site for avr9 is present on the plasma membranes of both resistant and susceptible tomato genotypes. we used mutant avr9 peptides to determine the relationship between elicitor activity of these peptides and their affinity to the binding site in the membranes of tomat ...	1998	9625714
glucocorticoid-inducible expression of a bacterial avirulence gene in transgenic arabidopsis induces hypersensitive cell death.	pathogenic strains of pseudomonas syringae pv. tomato carrying the avrrpt2 avirulence gene specifically induce a hypersensitive cell death response in arabidopsis plants that contain the complementary rps2 disease resistance gene. transient expression of avrrpt2 in arabidopsis plants having the rps2 gene has been shown to induce hypersensitive cell death. in order to analyze the effects of conditional expression of avrrpt2 in arabidopsis plants, transgenic lines were constructed that contained t ...	1998	9628020
cloning and characterization of an outer membrane protein of vibrio vulnificus required for heme utilization: regulation of expression and determination of the gene sequence.	vibrio vulnificus is a halophilic, marine pathogen that has been associated with septicemia and serious wound infections in patients with iron overload and preexisting liver disease. for v. vulnificus, the ability to acquire iron from the host has been shown to correlate with virulence. v. vulnificus is able to use host iron sources such as hemoglobin and heme. we previously constructed a fur mutant of v. vulnificus which constitutively expresses at least two iron-regulated outer membrane protei ...	1998	9632577
pad4 functions upstream from salicylic acid to control defense responses in arabidopsis.	the arabidopsis pad4 gene was previously shown to be required for synthesis of camalexin in response to infection by the virulent bacterial pathogen pseudomonas syringae pv maculicola es4326 but not in response to challenge by the non-host fungal pathogen cochliobolus carbonum. in this study, we show that pad4 mutants exhibit defects in defense responses, including camalexin synthesis and pathogenesis-related pr-1 gene expression, when infected by p. s. maculicola es4 326. no such defects were o ...	1998	9634589
resistance gene n-mediated de novo synthesis and activation of a tobacco mitogen-activated protein kinase by tobacco mosaic virus infection.	salicylic acid-induced protein kinase (sipk) and wounding-induced protein kinase (wipk), two distinct members of the mitogen-activated protein (map) kinase family, are activated in tobacco resisting infection by tobacco mosaic virus (tmv). wipk activation by tmv depends on the disease-resistance gene n because infection of susceptible tobacco not carrying the n gene failed to activate wipk. activation of wipk required not only posttranslational phosphorylation but also a preceding rise in its mr ...	1998	9636167
gene-for-gene disease resistance without the hypersensitive response in arabidopsis dnd1 mutant.	the cell death response known as the hypersensitive response (hr) is a central feature of gene-for-gene plant disease resistance. a mutant line of arabidopsis thaliana was identified in which effective gene-for-gene resistance occurs despite the virtual absence of hr cell death. plants mutated at the dnd1 locus are defective in hr cell death but retain characteristic responses to avirulent pseudomonas syringae such as induction of pathogenesis-related gene expression and strong restriction of pa ...	1998	9636234
toxin production by pathovars of pseudomonas syringae and their antagonistic activities against epiphytic microorganisms.	75 strains of 21 various pseudomonas syringae (p.) pathovars were investigated in different tests for their toxin production. data from literature about the production of the known phytotoxins phaseolotoxin (pv. phaseolicola), tabtoxin (pv. coronafaciens, pv. tabaci), coronatine (pv. atropurpurea, pv. glycinea, pv. maculicola, pv. morsprunorum, pv. tomato), and toxins of the lipodepsipeptide group (pv. aptata, pv. atrofaciens, pv. syringae) could be confirmed. besides, a production of the phytoh ...	1998	9637014
analysis of genes involved in biosynthesis of coronafacic acid, the polyketide component of the phytotoxin coronatine.	coronafacic acid (cfa) is the polyketide component of coronatine (cor), a phytotoxin produced by the plant-pathogenic bacterium pseudomonas syringae. the genes involved in cfa biosynthesis are encoded by a single transcript which encompasses 19 kb of the cor gene cluster. in the present study, the nucleotide sequence was determined for a 4-kb region located at the 3' end of the cfa biosynthetic gene cluster. three open reading frames were identified and designated cfa8, cfa9, and tnp1; the predi ...	1998	9642184
a highly selective pcr protocol for detecting 16s rrna genes of the genus pseudomonas (sensu stricto) in environmental samples.	pseudomonas species are plant, animal, and human pathogens; exhibit plant pathogen-suppressing properties useful in biological control; or express metabolic versatilities valued in biotechnology and bioremediation. specific detection of pseudomonas species in the environment may help us gain a more complete understanding of the ecological significance of these microorganisms. the objective of this study was to develop a pcr protocol for selective detection of pseudomonas (sensu stricto) in envir ...	1998	9647828
development of a lipase fermentation process that uses a recombinant pseudomonas alcaligenes strain.	pseudomonas alcaligenes m-1 secretes an alkaline lipase, which has excellent characteristics for the removal of fatty stains under modern washing conditions. a fed-batch fermentation process based on the secretion of the alkaline lipase from p. alcaligenes was developed. due to the inability of p. alcaligenes to grow on glucose, citric acid and soybean oil were applied as substrates in the batch phase and feed phase, respectively. the gene encoding the high-alkaline lipase from p. alcaligenes wa ...	1998	9647843
the defense-related rice gene pir7b encodes an alpha/beta hydrolase fold protein exhibiting esterase activity towards naphthol as-esters.	acquired resistance of rice to pyricularia oryzae, the causing agent of rice blast, can be induced by inoculation with the non-host pathogen pseudomonas syringae pv. syringae. we have previously cloned a cdna and a corresponding gene (pir7b) whose transcripts accumulate upon infiltration with the resistance-inducing bacteria. the putative encoded product pir7b exhibits significant sequence similarity to two recently cloned hydroxynitrile lyases from manihot esculenta (cassava) and hevea brasisli ...	1998	9652390
copper-binding compounds from methylosinus trichosporium ob3b.	two copper-binding compounds/cofactors (cbcs) were isolated from the spent media of both the wild type and a constitutive soluble methane monooxygenase (smmoc) mutant, pp319 (p. a. phelps et al., appl. environ. microbiol. 58:3701-3708, 1992), of methylosinus trichosporium ob3b. both cbcs are small polypeptides with molecular masses of 1,218 and 779 da for cbc-l1 and cbc-l2, respectively. the amino acid sequence of cbc-l1 is s?mypgs?m, and that of cbc-l2 is spmp?s. copper-free cbcs showed absorpt ...	1998	9658004
differential regulation of rhizobium etli rpon2 gene expression during symbiosis and free-living growth.	the rhizobium etli rpon1 gene, encoding the alternative sigma factor sigma54 (rpon), was recently characterized and shown to be involved in the assimilation of several nitrogen and carbon sources during free-living aerobic growth (j. michiels, t. van soom, i. d'hooghe, b. dombrecht, t. benhassine, p. de wilde, and j. vanderleyden, j. bacteriol. 180:1729-1740, 1998). we identified a second rpon gene copy in r. etli, rpon2, encoding a 54.0-kda protein which displays 59% amino acid identity with th ...	1998	9658006
induction of defense-related responses in cf9 tomato cells by the avr9 elicitor peptide of cladosporium fulvum is developmentally regulated	the avr9 elicitor from the fungal pathogen cladosporium fulvum induces defense-related responses, including cell death, specifically in tomato (lycopersicon esculentum mill.) plants that carry the cf-9 resistance gene. to study biochemical mechanisms of resistance in detail, suspension cultures of tomato cells that carry the cf-9 resistance gene were initiated. treatment of cells with various elicitors, except avr9, induced an oxidative burst, ion fluxes, and expression of defense-related genes. ...	1998	9662523
pathogen-induced changes in the antioxidant status of the apoplast in barley leaves	leaves of two barley (hordeum vulgare l.) isolines, alg-r, which has the dominant mla1 allele conferring hypersensitive race-specific resistance to avirulent races of blumeria graminis, and alg-s, which has the recessive mla1 allele for susceptibility to attack, were inoculated with b. graminis f. sp. hordei. total leaf and apoplastic antioxidants were measured 24 h after inoculation when maximum numbers of attacked cells showed hypersensitive death in alg-r. cytoplasmic contamination of the apo ...	1998	9662553
a newly identified regulator is required for virulence and toxin production in pseudomonas syringae.	the genes lema (which we here redesignate gacs) and gaca encode members of a widely conserved two-component regulatory system. in pseudomonas syringae strain b728a, gacs and gaca are required for lesion formation on bean, as well as for the production of protease and the toxin syringomycin. a gene, designated sala, was discovered that restored syringomycin production to a gacs mutant when present on a multiple-copy plasmid. disruption of chromosomal sala resulted in loss of syringomycin producti ...	1998	9663679
successful search for a resistance gene in tomato targeted against a virulence factor of a fungal pathogen.	the interaction between tomato and its fungal pathogen cladosporium fulvum complies with the gene-for-gene system, in which specific recognition of fungal proteins by plant genotypes with matching resistance genes results in host resistance. two proteins, ecp1 and ecp2, secreted by c. fulvum during infection, are required for full virulence of the fungus on tomato. we chose the most important virulence factor, ecp2, for a targeted search for hypersensitive response (hr)-based resistance among a ...	1998	9671796
the separation of alginate biosynthesis and acetylation in pseudomonas syringae.	seaweed alginate was acetylated by resting cells of pseudomonas syringae subsp. phaseolicola atcc 19304. physiological studies on this strain and its uv-induced mutants showed no correlation between bacterial alginate biosynthesis and acetylation. specific yields of alginate and degree of acetylation in these polymers varied with strain and culture medium. this was indirect evidence that alginate biosynthesis is separate from polysaccharide acetylation. it indicated that the enzyme system involv ...	1998	9674113
the extracytoplasmic function sigma factors: role and regulation.	alternative sigma factors provide a means of regulating gene expression in response to various extracellular changes. one such class of sigma factors appears to control a variety of functions, including expression of heat-shock genes in escherichia coli, biosynthesis of alginates and carotenoids in pseudomonas aeruginosa and myxococcus xanthus, respectively, iron uptake in e. coli and pseudomonas spp., nickel and cobalt efflux in alcaligenes europhus, plant pathogenicity in pseudomonas syringae ...	1998	9680198
molecular characterization of oxa-20, a novel class d beta-lactamase, and its integron from pseudomonas aeruginosa.	the pseudomonas aeruginosa mus clinical isolate produces oxa-18, a pi 5.5 class d extended-spectrum beta-lactamase totally inhibited by clavulanic acid (l. n. philippon, t. naas, a.-t. bouthors, v. barakett, and p. nordmann, antimicrob. agents chemother. 41:2188-2195, 1997). a second beta-lactamase was cloned, and the recombinant escherichia coli clone ppl10 expressed a pi 7.4 beta-lactamase which conferred high levels of amoxicillin and ticarcillin resistance and which was partially inhibited b ...	1998	9687410
phospholipid analysis and fractional reconstitution of the ice nucleation protein activity purified from escherichia coli overexpressing the inaz gene of pseudomonas syringae.	ice nucleation protein was partially purified from the membrane fraction of e. coli carrying inaz from pseudomonas syringae. the ice nucleation protein was totally localized in the bacterial envelope and was extracted by either salt (0.25 m nh4cl) or the nonionic detergent tween 20. the extracted protein was partially purified by sequential passage through deae-52 cellulose and sephacryl-s400 columns. the activity of the purified protein was lost after treatment with phospholipase c, and its act ...	1998	9698431
molecular characterization of an arabidopsis gene encoding hydroperoxide lyase, a cytochrome p-450 that is wound inducible.	hydroperoxide lyase (hpl) cleaves lipid hydroperoxides to produce volatile flavor molecules and also potential signal molecules. we have characterized a gene from arabidopsis that is homologous to a recently cloned hpl from green pepper (capsicum annuum). the deduced protein sequence indicates that this gene encodes a cytochrome p-450 with a structure similar to that of allene oxide synthase. the gene was cloned into an expression vector and expressed in escherichia coli to demonstrate hpl activ ...	1998	9701595
sequence variations in alleles of the avirulence gene avrpphe.r2 from pseudomonas syringae pv. phaseolicola lead to loss of recognition of the avrpphe protein within bean cells and a gain in cultivar-specific virulence.	the bean halo blight pathogen, pseudomonas syringae pv. phaseolicola (psph), is differentiated into nine races based on the presence or absence of five avirulence (avr) genes in the bacterium, which interact with corresponding resistance genes. r1-r5, in phaseolus vulgaris. the resistance gene r2 is matched by avrpphe, which is located adjacent to the cluster of hrp genes that are required for pathogenicity of psph. although only races 2, 4, 5 and 7 are avirulent on cultivars with r2 (inducing t ...	1998	9701811
nitric oxide functions as a signal in plant disease resistance.	recognition of an avirulent pathogen triggers the rapid production of the reactive oxygen intermediates superoxide (o2-) and hydrogen peroxide (h2o2). this oxidative burst drives crosslinking of the cell wall, induces several plant genes involved in cellular protection and defence, and is necessary for the initiation of host cell death in the hypersensitive disease-resistance response. however, this burst is not enough to support a strong disease-resistance response. here we show that nitric oxi ...	1998	9707120
the root knot nematode resistance gene mi from tomato is a member of the leucine zipper, nucleotide binding, leucine-rich repeat family of plant genes.	the mi locus of tomato confers resistance to root knot nematodes. tomato dna spanning the locus was isolated as bacterial artificial chromosome clones, and 52 kb of contiguous dna was sequenced. three open reading frames were identified with similarity to cloned plant disease resistance genes. two of them, mi-1.1 and mi-1.2, appear to be intact genes; the third is a pseudogene. a 4-kb mrna hybridizing with these genes is present in tomato roots. complementation studies using cloned copies of mi- ...	1998	9707531
a cloned erwinia chrysanthemi hrp (type iii protein secretion) system functions in escherichia coli to deliver pseudomonas syringae avr signals to plant cells and to secrete avr proteins in culture.	the hrp (type iii protein secretion) system is essential for the plant parasitic ability of pseudomonas syringae and most gram-negative bacterial plant pathogens. avrb and avrpto are two p. syringae proteins that have biological activity when produced via heterologous gene expression inside plant cells or when produced by hrp+ bacteria. avr-like proteins, presumably injected by the hrp system on bacterial contact with plant cells, appear to underlie pathogenic interactions, but none has been obs ...	1998	9707625
genetically engineered broad-spectrum disease resistance in tomato.	resistance in tomato to the bacterial pathogen pseudomonas syringae pathovar tomato requires pto and prf. mutations that eliminate prf show a loss of both pto resistance and sensitivity to the organophosphate insecticide fenthion, suggesting that prf controls both phenotypes. herein, we report that the overexpression of prf leads to enhanced resistance to a number of normally virulent bacterial and viral pathogens and leads to increased sensitivity to fenthion. these plants express levels of sal ...	1998	9707642
different requirements for eds1 and ndr1 by disease resistance genes define at least two r gene-mediated signaling pathways in arabidopsis.	the arabidopsis genes eds1 and ndr1 were shown previously by mutational analysis to encode essential components of race-specific disease resistance. here, we examined the relative requirements for eds1 and ndr1 by a broad spectrum of resistance (r) genes present in three arabidopsis accessions (columbia, landsberg-erecta, and wassilewskija). we show that there is a strong requirement for eds1 by a subset of r loci (rpp2, rpp4, rpp5, rpp21, and rps4), conferring resistance to the biotrophic oomyc ...	1998	9707643
evidence for growth of strains of the plant epiphytic bacterium erwinia herbicola and transconjugation among the bacterial strains in guts of the silkworm bombyx mori.	growth of plant epiphytic bacteria erwinia herbicola and pseudomonas syringae in guts of the silkworm, bombyx mori, was studied. fifth instar silkworm larvae were fed artificial diets supplemented with these bacteria for 6 to 12 h followed by uncontaminated diets. at 1, 3, and 6 days after feeding, bacteria were isolated from insect guts and feces. a much larger population of e. herbicola was detected in the samples collected 3 and 6 days after the inoculation than in samples collected after 1 d ...	1998	9709009
pas, a novel protein required for protein secretion and attaching and effacing activities of enterohemorrhagic escherichia coli.	enterohemorrhagic escherichia coli (ehec) exhibits a pattern of localized adherence to host cells, with the formation of microcolonies, and induces a specific histopathological phenotype collectively known as the attaching and effacing lesion. the genes encoding the products responsible for this phenotype are located on a 35-kb pathogenicity island designated the locus of enterocyte effacement, which is also shared by enteropathogenic e. coli. we have identified an open reading frame (orf) which ...	1998	9721271
chitinolytic activity in chromobacterium violaceum: substrate analysis and regulation by quorum sensing.	quorum sensing control mediated by n-acyl homoserine lactone (ahl) signaling molecules has been established as a key feature of the regulation of exoenzyme production in many gram-negative bacteria. in chromobacterium violaceum atcc 31532 a number of phenotypic characteristics, including production of the purple pigment violacein, hydrogen cyanide, antibiotics, and exoproteases are known to be regulated by the endogenous ahl n-hexanoyl-l-homoserine lactone (hhl). in this study we show that c. vi ...	1998	9721280
molecular characterization and sequence of a methionine biosynthetic locus from pseudomonas syringae.	two methionine biosynthetic genes in pseudomonas syringae pv. syringae, metx and metw, were isolated, sequenced, and evaluated for their roles in methionine biosynthesis and bacterial fitness on leaf surfaces. the metxw locus was isolated on a 1.8-kb dna fragment that was required for both methionine prototrophy and wild-type epiphytic fitness. sequence analysis identified two consecutive open reading frames (orfs), and in vitro transcription-translation experiments provided strong evidence that ...	1998	9721288
characterization of the hrpc and hrprs operons of pseudomonas syringae pathovars syringae, tomato, and glycinea and analysis of the ability of hrpf, hrpg, hrcc, hrpt, and hrpv mutants to elicit the hypersensitive response and disease in plants.	the species pseudomonas syringae encompasses plant pathogens with differing host specificities and corresponding pathovar designations. p. syringae requires the hrp (type iii protein secretion) system, encoded by a 25-kb cluster of hrp and hrc genes, in order to elicit the hypersensitive response (hr) in nonhosts or to be pathogenic in hosts. dna sequence analysis of the hrpc and hrprs operons of p. syringae pv. syringae 61 (brown spot of beans), p. syringae pv. glycinea u1 (bacterial blight of ...	1998	9721291
negative regulation of hrp genes in pseudomonas syringae by hrpv.	mutations in the five hrp and hrc genes in the hrpc operon of the phytopathogen pseudomonas syringae pv. syringae 61 have different effects on bacterial interactions with host and nonhost plants. the hrcc gene within the hrpc operon encodes an outer membrane component of the hrp secretion system that is conserved in all type iii protein secretion systems and is required for most pathogenic phenotypes and for secretion of the hrpz harpin to the bacterial milieu. the other four genes (in order), h ...	1998	9721292
novel escherichia coli umud' mutants: structure-function insights into sos mutagenesis.	although it has been 10 years since the discovery that the escherichia coli umud protein undergoes a reca-mediated cleavage reaction to generate mutagenically active umud', the function of umud' has yet to be determined. in an attempt to elucidate the role of umud' in sos mutagenesis, we have utilized a colorimetric papillation assay to screen for mutants of a hydroxylamine-treated, low-copy-number umud' plasmid that are unable to promote sos-dependent spontaneous mutagenesis. using such an appr ...	1998	9721309
a response regulator of cyanobacteria integrates diverse environmental signals and is critical for survival under extreme conditions.	microorganisms must sense their environment and rapidly tune their metabolism to ambient conditions to efficiently use available resources. we have identified a gene encoding a response regulator, nblr, that complements a cyanobacterial mutant unable to degrade its light-harvesting complex (phycobilisome), in response to nutrient deprivation. cells of the nblr mutant (i) have more phycobilisomes than wild-type cells during nutrient-replete growth, (ii) do not degrade phycobilisomes during sulfur ...	1998	9724820
cloning, nucleotide sequence, and expression in escherichia coli of levansucrase genes from the plant pathogens pseudomonas syringae pv. glycinea and p. syringae pv. phaseolicola.	plant-pathogenic bacteria produce various extracellular polysaccharides (epss) which may function as virulence factors in diseases caused by these bacteria. the eps levan is synthesized by the extracellular enzyme levansucrase in pseudomonas syringae, erwinia amylovora, and other bacterial species. the lsc genes encoding levansucrase from p. syringae pv. glycinea pg4180 and p. syringae pv. phaseolicola ncppb 1321 were cloned, and their nucleotide sequences were determined. heterologous expressio ...	1998	9726857
contribution of indole-3-acetic acid production to the epiphytic fitness of erwinia herbicola	erwinia herbicola 299r produces large quantities of indole-3-acetic acid (iaa) in culture media supplemented with l-tryptophan. to assess the contribution of iaa production to epiphytic fitness, the population dynamics of the wild-type strain and an iaa-deficient mutant of this strain on leaves were studied. strain 299xyle, an isogenic iaa-deficient mutant of strain 299r, was constructed by insertional interruption of the indolepyruvate decarboxylase gene of strain 299r with the xyle gene, which ...	1998	9726868
linkage map of escherichia coli k-12, edition 10: the traditional map.	this map is an update of the edition 9 map by berlyn et al. (m. k. b. berlyn, k. b. low, and k. e. rudd, p. 1715-1902, in f. c. neidhardt et al., ed., escherichia coli and salmonella: cellular and molecular biology, 2nd ed., vol. 2, 1996). it uses coordinates established by the completed sequence, expressed as 100 minutes for the entire circular map, and adds new genes discovered and established since 1996 and eliminates those shown to correspond to other known genes. the latter are included as ...	1998	9729611
yscb of yersinia pestis functions as a specific chaperone for yopn.	following contact with a eucaryotic cell, yersinia species pathogenic for humans (y. pestis, y. pseudotuberculosis, and y. enterocolitica) export and translocate a distinct set of virulence proteins (yope, yoph, yopj, yopm, and ypka) from the bacterium into the eucaryotic cell. during in vitro growth at 37 degrees c in the presence of calcium, yop secretion is blocked; however, in the absence of calcium, yop secretion is triggered. yop secretion occurs via a plasmid-encoded type iii, or "contact ...	1998	9733695
the o7 antigen of stenotrophomonas maltophilia is a linear d-rhamnan with a trisaccharide repeating unit that is also present in polymers for some pseudomonas and burkholderia species.	the o antigen polymer recovered from the reference strain for stenotrophomonas (xanthomonas or pseudomonas) maltophilia serogroup o7, after mild acid hydrolysis of the lipopolysaccharide, was constructed from d-rhamnose. by means of chemical degradations and nmr studies, the repeating unit of the polymer was shown to be a linear trisaccharide with the structure -->2)-alpha-d-rhap-(1-->3)-alpha-d-rhap-(1-->3)-alpha-d-r hap-(1-->. the same repeating unit is present in the common antigen of pseudom ...	1998	9741084
dna sequencing and analysis of the low-ca2+-response plasmid pcd1 of yersinia pestis kim5.	the low-ca2+-response (lcr) plasmid pcd1 of the plague agent yersinia pestis kim5 was sequenced and analyzed for its genetic structure. pcd1 (70,509 bp) has an incfiia-like replicon and a sopabc-like partition region. we have assigned 60 apparently intact open reading frames (orfs) that are not contained within transposable elements. of these, 47 are proven or possible members of the lcr, a major virulence property of human-pathogenic yersinia spp., that had been identified previously in one or ...	1998	9746557
characterization of the rice pathogen-related protein rir1a and regulation of the corresponding gene.	in rice (oryza sativa l.), local acquired resistance against pyricularia oryzae (cav.), the causal agent of rice blast, can be induced by a preinoculation with the non-host pathogen pseudomonas syringae pv. syringae. we have cloned a cdna (rir1a) and a closely related gene (rir1b) corresponding to transcripts that accumulate in leaf tissue upon inoculation with p. syringae pv. syringae. the cdna encodes a putative 107 amino acid protein, rir1a, that exhibits a putative signal peptide cleavage si ...	1998	9747803
a new class of caulobacter crescentus flagellar genes.	eight caulobacter crescentus flagellar genes, flma, flmb, flmc, flmd, flme, flmf, flmg, and flmh, have been cloned and characterized. these eight genes are clustered in pairs (flmab, flmcd, flmef, and flmgh) that appear to be structurally organized as operons. homology comparisons suggest that the proteins encoded by the flm genes may be involved in posttranslational modification of flagellins or proteins that interact with flagellin monomers prior to their assembly into a flagellar filament. ex ...	1998	9748431
hrpw of erwinia amylovora, a new harpin that contains a domain homologous to pectate lyases of a distinct class.	harpins, such as hrpn of erwinia amylovora, are extracellular glycine-rich proteins that elicit the hypersensitive reaction (hr). we identified hrpw of e. amylovora, which encodes a protein similar to known harpins in that it is acidic, rich in glycine and serine, and lacks cysteine. a putative hrpl-dependent promoter was identified upstream of hrpw, and western blot analysis of hrpl mutants indicated that the production of hrpw is regulated by hrpl. hrpw is secreted via the hrp (type iii) pathw ...	1998	9748455
the pseudomonas syringae pv. tomato hrpw protein has domains similar to harpins and pectate lyases and can elicit the plant hypersensitive response and bind to pectate.	the host-specific plant pathogen pseudomonas syringae elicits the hypersensitive response (hr) in nonhost plants and secretes the hrpz harpin in culture via the hrp (type iii) secretion system. previous genetic evidence suggested the existence of another harpin gene in the p. syringae genome. hrpw was found in a region adjacent to the hrp cluster in p. syringae pv. tomato dc3000. hrpw encodes a 42. 9-kda protein with domains resembling harpins and pectate lyases (pels), respectively. hrpw has ke ...	1998	9748456
the cytochrome c maturation operon is involved in manganese oxidation in pseudomonas putida gb-1.	a pseudomonas putida strain, strain gb-1, oxidizes mn2+ to mn oxide in the early stationary growth phase. it also secretes a siderophore (identified as pyoverdine) when it is subjected to iron limitation. after transposon (tn5) mutagenesis several classes of mutants with differences in mn2+ oxidation and/or secretion of the mn2+-oxidizing activity were identified. preliminary analysis of the tn5 insertion site in one of the nonoxidizing mutants suggested that a multicopper oxidase-related enzyme ...	1998	9758767
distribution and life strategies of two bacterial populations in a eutrophic lake	monoclonal antibodies and epifluorescence microscopy were used to determine the depth distribution of two indigenous bacterial populations in the stratified lake plusssee and characterize their life strategies. populations of comamonas acidovorans px54 showed a depth distribution with maximum abundances in the oxic epilimnion, whereas aeromonas hydrophila pu7718 showed a depth distribution with maximum abundances in the anoxic thermocline layer (metalimnion), i. e., in the water layer with the h ...	1998	9758799
genetic characterization of pseudomonas syringae pv. syringae strains from stone fruits in california	strains of pseudomonas syringae pv. syringae were isolated from healthy and diseased stone fruit tissues sampled from 43 orchard sites in california in 1995 and 1996. these strains, together with p. syringae strains from other hosts and pathovars, were tested for pathogenicity and the presence of the syrb and syrc genes and were genetically characterized by using enterobacterial repetitive intergenic consensus (eric) primers and pcr. all 89 strains of p. syringae pv. syringae tested were moderat ...	1998	9758805
characterization of genes involved in biosynthesis of a novel antibiotic from burkholderia cepacia bc11 and their role in biological control of rhizoctonia solani.	genetic manipulation of fluorescent pseudomonads has provided major insight into their production of antifungal molecules and their role in biological control of plant disease. burkholderia cepacia also produces antifungal activities, but its biological control activity is much less well characterized, in part due to difficulties in applying genetic tools. here we report genetic and biochemical characterization of a soil isolate of b. cepacia relating to its production of an unusual antibiotic t ...	1998	9758823
closely related plasmid replicons coexisting in the phytopathogen pseudomonas syringae show a mosaic organization of the replication region and altered incompatibility behavior	many pseudomonas syringae strains contain native plasmids that are important for host-pathogen interactions, and most of them contain several coexisting plasmids (ppt23a-like plasmids) that cross-hybridize to replication sequences from ppt23a, which also carries a gene cluster coding for the phytotoxin coronatine in p. syringae pv. tomato pt23. in this study, three functional ppt23a-like replicons were cloned from p. syringae pv. glycinea race 6, suggesting that the compatibility of highly relat ...	1998	9758824
pcr-based detection of the causal agent of watermark disease in willows (salix spp.)	the watermark disease, caused by brenneria salicis (formerly erwinia salicis), is of significant concern wherever tree-forming willows are grown or occur naturally. the movement of infected, asymptomatic cuttings is a major cause of pathogen dispersal. a reliable and sensitive diagnostic procedure is necessary for the safe movement of willow planting material. we derived primers from the nucleotide sequence of the 16s rrna gene of b. salicis for the development of a pcr to detect this pathogen. ...	1998	9758827
resistance to tellurite as a selection marker for genetic manipulations of pseudomonas strains.	resistance to the toxic compound potassium tellurite (telr) has been employed as a selection marker built into a set of transposon vectors and broad-host-range plasmids tailored for genetic manipulations of pseudomonas strains potentially destined for environmental release. in this study, the activated telr determinants encoded by the cryptic telab genes of plasmid rk2 were produced, along with the associated kila gene, as dna cassettes compatible with cognate vectors. in one case, the telr dete ...	1998	9758838
efficacy of syringomycin e in a murine model of vaginal candidiasis.	syringomycin e (sr-e), a new antifungal produced by the bacterium pseudomonas syringae pv. syringae, was evaluated in a murine vaginal candidiasis model. in one study, mice were treated intravaginally b.i.d. for 4 days with drug carrier, sr-e 2% in either peg-400 or peg-ointment, or 1% clotrimazole as a positive control. quantitative vaginal cultures were taken prior to treatment on day 1 and on days 5, 6, and 7. both formulations showed a reduction of yeast colonization in the vaginas on day 5 ...	1998	9766466
the espb protein of enteropathogenic escherichia coli is targeted to the cytoplasm of infected hela cells.	the espb protein of enteropathogenic escherichia coli (epec) is exported via a type iii secretion apparatus. espb is critical for signaling the host cell and for the development of the attaching and effacing lesion characteristic of epec infection. we used cellular fractionation and confocal laser scanning microscopy to determine the cellular location of espb during infection of hela cells. both methods indicated that espb is targeted to the cytoplasm of infected cells. using mutants, we found t ...	1998	9784563
characterization of the phytopathogen pseudomonas syringae pathovar ribicola ncppb 963.	in 1939, a bacterial spot caused severe defoliation of ribes aureum (golden currant) the causal agent is now recognized as pseudomonas syringae pathovar ribicola. this communication extends the phenotype of the only identified strain of p. syringae pv. ribicola, which is reminiscent of those of other pathovars, and provides a molecular biological characterization. a minimum size of 5.55 mb for the bacterial genome was obtained using pulsed-field electrophoresis. the sds-page outer-membrane profi ...	1998	9785483
initial binding of shiga toxin-producing escherichia coli to host cells and subsequent induction of actin rearrangements depend on filamentous espa-containing surface appendages.	shiga toxin-producing escherichia coli (stec) induce so-called attaching and effacing lesions that enable the tight adherence of these pathogens to the gut epithelium. all of the genes necessary for this process are present in the locus of enterocyte effacement, which encodes a type iii secretion system, the secreted esp proteins and the surface protein intimin. in this study we sequenced the espa gene of stec, generated and characterized a corresponding deletion mutant and raised espa-specific ...	1998	9786192
the yersinia deadly kiss.		1998	9791096
molecular genetic analysis of phosphite and hypophosphite oxidation by pseudomonas stutzeri wm88.	the first molecular and genetic characterization of a biochemical pathway for oxidation of the reduced phosphorus (p) compounds phosphite and hypophosphite is reported. the pathway was identified in pseudomonas stutzeri wm88, which was chosen for detailed studies from a group of organisms isolated based on their ability to oxidize hypophosphite (+1 valence) and phosphite (+3 valence) to phosphate (+5 valence). the genes required for oxidation of both compounds by p. stutzeri wm88 were cloned on ...	1998	9791102
physiological diversity of the rhizosphere diazotroph assemblages of selected salt marsh grasses.	rhizosphere diazotroph assemblages of salt marsh grasses are thought to be influenced by host plant species and by a number of porewater geochemical parameters. several geochemical variables can adversely affect plant productivity and spatial distributions, resulting in strong zonation of plant species and growth forms. this geochemically induced stress may also influence the species compositions and distributions of rhizosphere diazotroph assemblages, but little is currently known about these o ...	1998	9797277
detection of ralstonia solanacearum, which causes brown rot of potato, by fluorescent in situ hybridization with 23s rrna-targeted probes.	during the past few years, ralstonia (pseudomonas) solanacearum race 3, biovar 2, was repeatedly found in potatoes in western europe. to detect this bacterium in potato tissue samples, we developed a method based on fluorescent in situ hybridization (fish). the nearly complete genes encoding 23s rrna of five r. solanacearum strains and one ralstonia pickettii strain were pcr amplified, sequenced, and analyzed by sequence alignment. this resulted in the construction of an unrooted tree and suppor ...	1998	9797321
characterization of type iv pilus genes in pseudomonas syringae pv. tomato dc3000.	many strains of pseudomonas syringae produce retractile pili that act as receptors for lytic bacteriophage phi 6. as these are also characteristics of type iv pili, it was postulated that p. syringae may possess genes for type iv pilus biogenesis. a cosmid clone bank of p. syringae pv. tomato dc3000 genomic dna was used to complement a mutant of pseudomonas aeruginosa defective in the pild (xcpa) prepilin peptidase gene by selection for restoration of extracellular protein secretion, a function ...	1998	9805392
a nitrilase-like protein interacts with gcc box dna-binding proteins involved in ethylene and defense responses.	ethylene-responsive element-binding proteins (erebps) of tobacco (nicotiana tabacum l.) bind to the gcc box of many pathogenesis-related (pr) gene promoters, including osmotin (pr-5). the two gcc boxes on the osmotin promoter are known to be required, but not sufficient, for maximal ethylene responsiveness. erebps participate in the signal transduction pathway leading from exogenous ethylene application and pathogen infection to pr gene induction. in this study erebp3 was used as bait in a yeast ...	1998	9808731
localized changes in peroxidase activity accompany hydrogen peroxide generation during the development of a nonhost hypersensitive reaction in lettuce	peroxidase activity was characterized in lettuce (lactuca sativa l.) leaf tissue. changes in the activity and distribution of the enzyme were examined during the development of a nonhost hypersensitive reaction (hr) induced by pseudomonas syringae (p. s.) pv phaseolicola and in response to an hrp mutant of the bacterium. assays of activity in tissue extracts revealed ph optima of 4.5, 6.0, 5.5 to 6.0, and 6.0 to 6.5 for the substrates tetramethylbenzidine, guaiacol, caffeic acid, and chlorogenic ...	1998	9808752
role of ergosterol in growth inhibition of saccharomyces cerevisiae by syringomycin e.	the antifungal activity of the lipodepsipeptide syringomycin e from pseudomonas syringae pv. syringae is modulated by sterols. to study the requirement of the predominant fungal sterol, ergosterol, in syringomycin e action, the sterol composition of saccharomyces cerevisiae sterol auxotroph strain fy-14 was modified and sensitivity to syringomycin e examined. cells containing solely ergosterol, cholesterol, beta-sitosterol or stigmasterol were sensitive to syringomycin e with the latter two bein ...	1998	9809422
mutational analysis of the role of nucleoside triphosphatase p4 in the assembly of the rna polymerase complex of bacteriophage phi6.	bacteriophage phi6 is a complex enveloped double-stranded rna virus with a segmented genome and replication strategy quite similar to that of the reoviridae. an in vitro packaging and replication system using purified components is available. the positive-polarity genomic segments are translocated into a preformed polymerase complex (procapsid) particle. this particle is composed of four proteins: the shell-forming protein p1, the rna polymerase p2, and two proteins active in packaging. protein ...	1998	9811745
solution conformation of the pseudomonas syringae msu 16h phytotoxic lipodepsipeptide pseudomycin a determined by computer simulations using distance geometry and molecular dynamics from nmr data.	pseudomycin a is a cyclic lipodepsinonapeptide phytotoxin produced by a strain of the plant pathogenic bacterium pseudomonas syringae. like other members of this family of bacterial metabolites, it is characterised by a fatty acylated cyclic peptide with mixed chirality and lactonic closure. several biological activities of pseudomycin a are lower than those found for some of its congeners, a difference which might depend on the diverse number and distribution of charged residues in the peptide ...	1998	9826192
the type iv leader peptidase/n-methyltransferase of vibrio vulnificus controls factors required for adherence to hep-2 cells and virulence in iron-overloaded mice.	vibrio vulnificus expresses a number of potential virulence determinants that may contribute to its ability to cause a severe and rapidly disseminating septicemia in susceptible hosts. we have cloned and characterized two genes encoding products related to components of the type iv pilus biogenesis and general secretory (type ii) pathways by complementation of a type iv peptidase/n-methyltransferase (pild) mutant of pseudomonas aeruginosa with a v. vulnificus genomic library. one of the genes (v ...	1998	9826339
complete dna sequence and detailed analysis of the yersinia pestis kim5 plasmid encoding murine toxin and capsular antigen.	yersinia pestis, the causative agent of plague, harbors at least three plasmids necessary for full virulence of the organism, two of which are species specific. one of the y. pestis-specific plasmids, pmt1, is thought to promote deep tissue invasion, resulting in more acute onset of symptoms and death. we determined the entire nucleotide sequence of y. pestis kim5 pmt1 and identified potential open reading frames (orfs) encoded by the 100,990-bp molecule. based on codon usage for known yersinial ...	1998	9826348