Publications

induced instability of two arabidopsis constitutive pathogen-response alleles.	paramutation is an example of a non-mendelian-directed allelic interaction that results in the epigenetic alteration of one allele. we describe a paramutation-like interaction between two alleles, bal and cpr1-1 (constitutive expressor of pr genes 1), which map to a complex r-like gene cluster on arabidopsis chromosome 4. both alleles cause dwarfing and constitutive defense responses, similar to another dwarf variant, ssi1 (suppressor of sa-insensitivity 1). previous work has demonstrated that t ...	2002	12032362
genomewide identification of proteins secreted by the hrp type iii protein secretion system of pseudomonas syringae pv. tomato dc3000.	the ability of pseudomonas syringae pv. tomato dc3000 to be pathogenic on plants depends on the hrp (hypersensitive response and pathogenicity) type iii protein secretion system and the effector proteins it translocates into plant cells. through iterative application of experimental and computational techniques, the dc3000 effector inventory has been substantially enlarged. five homologs of known avirulence (avr) proteins and five effector candidates, encoded by genes with putative hrp promoters ...	2002	12032338
overexpression of polyphenol oxidase in transgenic tomato plants results in enhanced bacterial disease resistance.	polyphenol oxidases (ppos; ec 1.10.3.2 or ec 1.14.18.1) catalyzing the oxygen-dependent oxidation of phenols to quinones are ubiquitous among angiosperms and assumed to be involved in plant defense against pests and pathogens. in order to investigate the role of ppo in plant disease resistance, we made transgenic tomato ( lycopersicon esculentum mill. cv. money maker) plants that overexpressed a potato ( solanum tuberosum l.) ppo cdna under control of the cauliflower mosaic virus 35s promoter. t ...	2002	12029473
yersinia enterocolitica type iii secretion: mutational analysis of the yopq secretion signal.	pathogenic yersinia spp. secrete yop proteins via the type iii pathway. yopq codons 1 to 15 were identified as a signal necessary and sufficient for the secretion of a fused reporter protein. frameshift mutations that alter codons 2 to 15 with little alteration of yopq mrna sequence do not abolish type iii transport, suggesting a model in which yopq mrna may provide a signal for secretion (d. m. anderson and o. schneewind, mol. microbiol. 31:1139-1148, 2001). in a recent study, the yope signal w ...	2002	12029049
the arabidopsis hrl1 mutation reveals novel overlapping roles for salicylic acid, jasmonic acid and ethylene signalling in cell death and defence against pathogens.	defence against pathogens in arabidopsis is orchestrated by at least three signalling molecules: salicylic acid (sa), jasmonic acid (ja) and ethylene (et). the hrl1 (hypersensitive response-like lesions 1) mutant of arabidopsis is characterized by spontaneous necrotic lesions, accumulation of reactive oxygen species, constitutive expression of sa- and et/ja-responsive defence genes, and enhanced resistance to virulent bacterial and oomycete pathogens. epistasis analyses of hrl1 with npr1, etr1, ...	2002	12028576
pseudomonas lipodepsipeptides and fungal cell wall-degrading enzymes act synergistically in biological control.	pseudomonas syringae pv. syringae strain b359 secreted two main lipodepsipeptides (ldps), syringomycin e (sre) and syringopeptin 25a (sp25a), together with at least four types of cell wall-degrading enzymes (cwdes). in antifungal bioassays, the purified toxins sre and sp25a interacted synergistically with chitinolytic and glucanolytic enzymes purified from the same bacterial strain or from the biocontrol fungus trichoderma atroviride strain p1. the synergism between ldps and cwdes occurred again ...	2002	12026170
[some characteristics of pseudomonas syringae pv. maculicola dissociants].	pseudomonas syringae pv. maculicola dissociants producing colonies of different morphotype were found to possess similar biochemical and serological properties but different virulence to the host plant. the heterogeneous extracellular and intracellular lipopolysaccharide-protein complexes of the dissociants differed in their chemical composition and biological activity towards test plants.	2002	12024826
construction of pmekm12, an expression vector for protein production in pseudomonas syringae.	characterization of the biological roles of proteins is essential for functional genomics of pseudomonads. heterologous proteins overproduced in escherichia coli frequently fail to exhibit biological function. to circumvent this problem, vector pmekm12 was constructed and used to overexpress proteins in pseudomonas. the vector contains the pro1600 replication origin, the maltose-binding protein (mbp) fusion system, and an inducible tac promoter. the pmekm12 was successfully used to overexpress t ...	2002	12023087
dna markers for identification of pseudomonas syringae pv. actinidiae.	the specific dna fragment was screened by rapd analysis of pseudomonas syringae pv. actinidiae, as well as similar strains that were isolated from kiwifruits. the primer c24 detected a fragment that is specific in p. syringae pv. actinidiae. this fragment was cloned. the pathovar-specific fragment was detected from a southern blot analysis of the genomic dnas of p. syringae pv. actinidiae using the cloned fragment as a probe. the sequence size of the cloned fragment was determined as 675 bp. a d ...	2002	12018854
a plant gene up-regulated at rust infection sites.	expression of the fis1 gene from flax (linum usitatissimum) is induced by a compatible rust (melampsora lini) infection. infection of transgenic plants containing a beta-glucuronidase (gus) reporter gene under the control of the fis1 promoter showed that induction is highly localized to those leaf mesophyll cells within and immediately surrounding rust infection sites. the level of induction reflects the extent of fungal growth. in a strong resistance reaction, such as the hypersensitive fleck m ...	2002	12011348
a new syringopeptin produced by bean strains of pseudomonas syringae pv. syringae.	two strains (b728a and y37) of the phytopathogenic bacterium pseudomonas syringae pv. syringae isolated from bean (phaseolus vulgaris) plants were shown to produce in culture both syringomycin, a lipodepsinonapeptide secreted by the majority of the strains of the bacterium, and a new form of syringopeptin, sp(22)phv. the structure of the latter metabolite was elucidated by the combined use of mass spectrometry (ms), nuclear magnetic resonance (nmr) spectroscopy and chemical procedures. comparati ...	2002	12009406
methylation of inorganic and organic selenium by the bacterial thiopurine methyltransferase.	escherichia coli cells expressing the tpm gene encoding the bacterial thiopurine methyltransferase (btpmt) are shown to methylate selenite and (methyl)selenocysteine into dimethylselenide (dmse) and dimethyldiselenide (dmdse). e. coli cells expressing tpm from a gene library cosmid clone (harboring a pseudomonas syringae insert of about 20 kb) also methylated selenate into dmse and dmdse. btpmt is the first methyltransferase shown to be involved in the methylation of these selenium derivatives.	2002	12003960
targets of atwrky6 regulation during plant senescence and pathogen defense.	in arabidopsis, wrky factors comprise a large gene family of plant-specific transcriptional regulators controlling several types of plant stress responses. to understand the regulatory role of wrky proteins during such processes, we identified targets of the senescence- and defense-associated wrky6 factor. wrky6 was found to suppress its own promoter activity as well as that of a closely related wrky family member, indicating negative autoregulation. on the other hand, wrky6 positively influence ...	2002	12000796
the r1 gene for potato resistance to late blight (phytophthora infestans) belongs to the leucine zipper/nbs/lrr class of plant resistance genes.	late blight caused by the oomycete phytophthora infestans is the most destructive disease in potato cultivation worldwide. new, more virulent p. infestans strains have evolved which overcome the genetic resistance that has been introgressed by conventional breeding from wild potato species into commercial varieties. r genes (for single-gene resistance) and genes for quantitative resistance to late blight are present in the germplasm of wild and cultivated potato. the molecular basis of single-ge ...	2002	12000683
siderophore-mediated signaling regulates virulence factor production in pseudomonasaeruginosa.	numerous bacteria secrete low molecular weight compounds termed siderophores that have a high affinity for iron ions. siderophores have a well-documented role as iron-scavenging chemicals, chelating iron ions in the environment whereupon the ferrisiderophores reenter the bacterial cells by means of specific cell-surface receptors. the iron is then released for incorporation into bacterial proteins. here we show that in addition to its role as an iron-scavenger, the siderophore pyoverdine that is ...	2002	11997446
distribution of type iii secretion gene clusters in burkholderia pseudomallei, b. thailandensis and b. mallei.	burkholderia pseudomallei, the causative agent of melioidosis, carries a cluster of genes closely related in organisation to the type iii secretion (tts) system gene clusters of the plant pathogens ralstonia solanacearum and xanthomonas spp. the tts gene cluster (tts1) is present only in b. pseudomallei and not in avirulent b. thailandensis. adjacent to the gene cluster encoding putative secreton structural proteins lie a number of open reading frames (orfs) encoding putative proteins with littl ...	2002	11990489
role of glucose in enhancing the temperature-dependent growth inhibition of escherichia coli o157:h7 atcc 43895 by a pseudomonas sp.	growth of escherichia coli o157:h7 strain atcc 43895 was monitored at 5, 10, 15, and 25 degrees c in both pure and mixed (1:1) cultures with a gluconate-producing pseudomonas sp. found in meat to evaluate the effect of the absence and presence of 1% glucose in broth on temperature-dependent competition. the number of colonies of the pseudomonas strain exceeded 9 log cfu/ml under all conditions tested. the pathogen grew better as the temperature increased from 10 to 15 and 25 degrees c and grew b ...	2002	11976143
isolation and characterization of broad-spectrum disease-resistant arabidopsis mutants.	to identify arabidopsis mutants that constitutively express systemic acquired resistance (sar), we constructed reporter lines expressing the firefly luciferase gene under the control of the sar-inducible pr-1 promoter (pr-1/luc). after ems mutagenesis of a well-characterized transgenic line, we screened 250,000 m(2) plants for constitutive expression of the reporter gene in vivo. from a mutant collection containing several hundred putative mutants, we concentrated on 16 mutants lacking spontaneo ...	2002	11973319
tomato transcription factors pti4, pti5, and pti6 activate defense responses when expressed in arabidopsis.	the pti4, pti5, and pti6 proteins from tomato were identified based on their interaction with the product of the pto disease resistance gene, a ser-thr protein kinase. they belong to the ethylene-response factor (erf) family of plant-unique transcription factors and bind specifically to the gcc-box cis element present in the promoters of many pathogenesis-related (pr) genes. here, we show that these tomato erfs are localized to the nucleus and function in vivo as transcription activators that re ...	2002	11971137
synthetic plant promoters containing defined regulatory elements provide novel insights into pathogen- and wound-induced signaling.	pathogen-inducible plant promoters contain multiple cis-acting elements, only some of which may contribute to pathogen inducibility. therefore, we made defined synthetic promoters containing tetramers of only a single type of element and present evidence that a range of cis-acting elements (boxes w1, w2, gcc, jere, s, gst1, and d) can mediate local gene expression in planta after pathogen attack. the expression patterns of the promoters were monitored during interactions with a number of pathoge ...	2002	11971132
the arabidopsis gain-of-function mutant dll1 spontaneously develops lesions mimicking cell death associated with disease.	we describe the characterization of a novel gain-of-function arabidopsis mutant, dll1 (disease-like lesions1), which spontaneously develops lesions mimicking bacterial speck disease and constitutively expresses biochemical and molecular markers associated with pathogen infection. despite the constitutive expression of defense-related responses, dll1 is unable to suppress the growth of virulent pathogens. however, dll1 elicits normal hypersensitive response in response to avirulent pathogens, thu ...	2002	11967093
identification of pseudomonas syringae pv. tomato genes induced during infection of arabidopsis thaliana.	phytopathogenic bacteria possess a large number of genes that allow them to grow and cause disease on plants. many of these genes should be induced when the bacteria come in contact with plant tissue. we used a modified in vivo expression technology (ivet) approach to identify genes from the plant pathogen pseudomonas syringae pv. tomato that are induced upon infection of arabidopsis thaliana and isolated over 500 in planta-expressed (ipx) promoter fusions. sequence analysis of 79 fusions reveal ...	2002	11967070
tcrb, a gene conferring transferable copper resistance in enterococcus faecium: occurrence, transferability, and linkage to macrolide and glycopeptide resistance.	a newly discovered gene, designated tcrb, which is located on a conjugative plasmid conferring acquired copper resistance in enterococcus faecium, was identified in an isolate from a pig. the tcrb gene encodes a putative protein belonging to the cpx-type atpase family with homology (46%) to the copb protein from enterococcus hirae. the tcrb gene was found in e. faecium isolated from pigs (75%), broilers (34%), calves (16%), and humans (10%) but not in isolates from sheep. resistant isolates, con ...	2002	11959576
a phylogenomic study of the octase genes in pseudomonas syringae pathovars: the horizontal transfer of the argk-tox cluster and the evolutionary history of octase genes on their genomes.	phytopathogenic pseudomonas syringae is subdivided into about 50 pathovars due to their conspicuous differentiation with regard to pathogenicity. based on the results of a phylogenetic analysis of four genes (gyrb, rpod, hrpl, and hrps), sawada et al. (1999) showed that the ancestor of p. syringae had diverged into at least three monophyletic groups during its evolution. physical maps of the genomes of representative strains of these three groups were constructed, which revealed that each strain ...	2002	11956683
rin4 interacts with pseudomonas syringae type iii effector molecules and is required for rpm1-mediated resistance in arabidopsis.	in arabidopsis, rpm1 confers resistance against pseudomonas syringae expressing either of two sequence unrelated type iii effectors, avrrpm1 or avrb. an rpm1-interacting protein (rin4) coimmunoprecipitates from plant cell extracts with avrb, avrrpm1, or rpm1. reduction of rin4 protein levels inhibits both the hypersensitive response and the restriction of pathogen growth controlled by rpm1. rin4 reduction causes diminution of rpm1. rin4 reduction results in heightened resistance to virulent pero ...	2002	11955429
the hrp pilus of pseudomonas syringae elongates from its tip and acts as a conduit for translocation of the effector protein hrpz.	the type iii secretion system (ttss) is an essential requirement for the virulence of many gram-negative bacteria infecting plants, animals and man. pathogens use the ttss to deliver effector proteins from the bacterial cytoplasm to the eukaryotic host cell, where the effectors subvert host defences. plant pathogens have to translocate their effector proteins through the plant cell wall barrier. the best candidates for directing effector protein traffic are bacterial appendages attached to the m ...	2002	11953310
molecular determinants required for the avirulence function of avrpphb in bean and other plants.	the avirulence gene avrpphb from pseudomonas syringae pv. phaseolicola determines incompatibility, manifested as a hypersensitive reaction (hr), on bean cultivars carrying the r3 resistance gene and also confers avirulence on other plants. the avrpphb protein carries an embedded consensus myristoylation motif and is cleaved in bacteria and certain plants to yield fragments of about 6 and 28 kda. we investigated plant recognition and type iii translocation determinants in avrpphb by constructing ...	2002	11952132
functional analyses of the pto resistance gene family in tomato and the identification of a minor resistance determinant in a susceptible haplotype.	pto is a member of a multigene family and encodes a serine/threonine kinase that mediates gene-for-gene resistance to strains of pseudomonas syringae pv. tomato expressing avrpto. the inferred amino acid sequence of the pto homologs from both resistant (lpimpth2 to lpimpth4) and susceptible (lescfen, lescpth2 to lescpth5) haplotypes suggested that most could encode functional serine/threonine kinases. in addition, the activation segments of the homologs are similar in sequence to that of pto, an ...	2002	11952131
identification of arabidopsis ethylene-responsive element binding factors with distinct induction kinetics after pathogen infection.	ethylene-responsive element binding factors (erf) proteins are plant-specific transcription factors, many of which have been linked to stress responses. we have identified four arabidopsis erf genes whose expression was specifically induced by avirulent and virulent strains of the bacterial pathogen pseudomonas syringae pv tomato, with overlapping but distinct induction kinetics. however, a delay in erf mrna accumulation after infection with the virulent strain was observed when compared with th ...	2002	11950980
ocatin. a novel tuber storage protein from the andean tuber crop oca with antibacterial and antifungal activities.	the most abundant soluble tuber protein from the andean crop oca (oxalis tuberosa mol.), named ocatin, has been purified and characterized. ocatin accounts for 40% to 60% of the total soluble oca tuber proteins, has an apparent molecular mass of 18 kd and an isoelectric point of 4.8. this protein appears to be found only in tubers and is accumulated only within the cells of the pith and peridermis layers (peel) of the tuber as it develops. ocatin inhibits the growth of several phytopathogenic ba ...	2002	11950978
altering the expression of the chlorophyllase gene athcor1 in transgenic arabidopsis caused changes in the chlorophyll-to-chlorophyllide ratio.	the arabidopsis gene athcor1, which encodes the cori1 (coronatine-induced) protein, was expressed in bacterial cells. soluble recombinant cori1 was purified and shown to possess chlorophyllase (chlase) activity in vitro. to determine its activity in vivo, wild-type arabidopsis and coi1 mutant, which lacks athcor1 transcripts, were transformed with sense and antisense forms of the gene. wild-type and coi1 plants overexpressing athcor1 showed increased contents of chlorophyllide (chlide) without a ...	2002	11950974
preexisting systemic acquired resistance suppresses hypersensitive response-associated cell death in arabidopsis hrl1 mutant.	the hypersensitive response (hr) displayed by resistant plants against invading pathogens is a prominent feature of plant-pathogen interactions. the arabidopsis hypersensitive response like lesions1 (hrl1) mutant is characterized by heightened defense responses that make it more resistant to virulent pathogens. however, hrl1 suppresses avirulent pathogen-induced hr cell death. furthermore, the high pr-1 expression observed in hrl1 remains unaltered after avirulent and virulent pathogen infection ...	2002	11950972
multigene engineering: dawn of an exciting new era in biotechnology.	development of a rice variety enriched in provitamin a, the accumulation of polyhydroxybutyrate polyester in arabidopsis nuclear transgenic plants (with enzymes targeted to chloroplasts in both), and the expression of bacterial operons via the chloroplast genome are recent landmark achievements in multigene engineering. hyper-expression of transgenes has resulted in the formation of insecticidal protein crystals or inclusion bodies of pharmaceutical proteins in transgenic chloroplasts, achieving ...	2002	11950565
functional analysis of hrpf, a putative type iii translocon protein from xanthomonas campestris pv. vesicatoria.	type iii secretion systems (ttsss) are specialized protein transport systems in gram-negative bacteria which target effector proteins into the host cell. the ttss of the plant pathogen xanthomonas campestris pv. vesicatoria, encoded by the hrp (hypersensitive reaction and pathogenicity) gene cluster, is essential for the interaction with the plant. one of the secreted proteins is hrpf, which is required for pathogenicity but dispensable for type iii secretion of effector proteins in vitro, sugge ...	2002	11948151
species-specific repetitive extragenic palindromic (rep) sequences in pseudomonas putida.	pseudomonas putida kt2440 is a soil bacterium that effectively colonises the roots of many plants and degrades a variety of toxic aromatic compounds. its genome has recently been sequenced. we describe that a 35 bp sequence with the structure of an imperfect palindrome, originally found repeated three times downstream of the rpoh gene terminator, is detected more than 800 times in the chromosome of this strain. the structure of this dna segment is analogous to that of the so-called enterobacteri ...	2002	11937637
genetically modified parthenocarpic eggplants: improved fruit productivity under both greenhouse and open field cultivation.	parthenocarpy, or fruit development in the absence of fertilization, has been genetically engineered in eggplant and in other horticultural species by using the defh9-iaam gene. the iaam gene codes for tryptophan monoxygenase and confers auxin synthesis, while the defh9 controlling regions drive expression of the gene specifically in the ovules and placenta. a previous greenhouse trial for winter production of genetically engineered (gm) parthenocarpic eggplants demonstrated a significant increa ...	2002	11934354
control of temperature-responsive synthesis of the phytotoxin coronatine in pseudomonas syringae by the unconventional two-component system corrps.	the phytopathogen pseudomonas syringae produces the phytotoxin coronatine (cor) as a major virulence factor. cor and its precursor, coronafacic acid, function as molecular mimics of the plant signaling molecule jasmonate. a 32.8-kb plasmid-borne gene cluster mediates cor biosynthesis, which is optimal at 18 degrees c and non-detectable at 28 degrees c, the optimal growth temperature for p. syringae. the thermoregulation is mediated at the transcriptional level by an unconventional two-component ...	2002	11931546
tabtoxin-resistant protein: overexpression, purification, and characterization.	one of the self-protection mechanisms in pseudomonas syringae pv. tabaci, a pathogen of tobacco wildfire, is thought to be due to its tabtoxin-resistance gene (ttr). in this study, the ttr gene was inserted into an expression vector, pqe30, and successfully expressed in escherichia coli m15 at high levels. the purified recombinant tabtoxin-resistant protein (ttr) had an apparent molecular mass of about 21 kda on sds-page as well as by mass spectroscopy and had a pi of 6.6 on isoelectric focusing ...	2002	11922760
a kinetic model describing cell growth and production of highly active, recombinant ice nucleation protein in escherichia coli.	a structured kinetic model, which describes the production of the recombinant ice nucleation protein in different conditions, was applied. the model parameters were estimated based on the variation of the specific growth rate and the intracellular product concentration during cultivation. the equations employed relate the cellular plasmid content or plasmid copy number with the cloned-gene expression; these correlations were successfully tested on the experimental data. the optimal nutrient cond ...	2002	11920448
the tobacco bzip transcription factor bzi-1 binds to g-box elements in the promoters of phenylpropanoid pathway genes in vitro, but it is not involved in their regulation in vivo.	screening of a tobacco (nicotiana tabacum) cdna library resulted in the isolation of a clone encoding the bzip transcription factor bzi-1. with respect to amino acid sequence, conservation of protein domains, genomic exon-intron structure and expression pattern, bzi-1 is closely related to cprf2, ohp1/2, blz1 and reb, a group of bzip proteins which have been described in a number of dicot and monocot species. bzi-1 exhibits the characteristics of a transcription factor. it binds to g-box and c-b ...	2002	11919711
molecular method to assess the diversity of burkholderia species in environmental samples.	in spite of the importance of many members of the genus burkholderia in the soil microbial community, no direct method to assess the diversity of this genus has been developed so far. the aim of this work was the development of soil dna-based pcr-denaturing gradient gel electrophoresis (dgge), a powerful tool for studying the diversity of microbial communities, for detection and analysis of the burkholderia diversity in soil samples. primers specific for the genus burkholderia were developed bas ...	2002	11916673
the inhibition of ice nucleators by insect antifreeze proteins is enhanced by glycerol and citrate.	antifreeze proteins depress the freezing point of water while not affecting the melting point, producing a characteristic difference in freezing and melting points termed thermal hysteresis. larvae of the beetle dendroides canadensis accumulate potent antifreeze proteins (dafps) in their hemolymph and gut, but to achieve high levels of thermal hysteresis requires enhancers, such as glycerol. dafps have previously been shown to inhibit the activity of bacterial and hemolymph protein ice nucleator ...	2002	11916110
global regulation by gida in pseudomonas syringae.	analysis of two virulence mutants of pseudomonas syringae b728a revealed that the tn 5 sites of insertion were within the gida open reading frame (orf). these mutations were pleiotropic, affecting diverse phenotypic traits, such as lipodepsipeptide (syringomycin and syringopeptin) antibiotic production, swarming, presence of fluorescent pigment, and virulence. site-specific recombination of a disrupted gida gene into the chromosome resulted in the same phenotypic pattern as transposon insertion. ...	2002	11914360
analysis and expression of algl, which encodes alginate lyase in pseudomonas syringae pv. syringae.	pseudomonas syringae produces alginate, an exopolysaccharide that contributes to the virulence and epiphytic fitness of this phytopathogenic bacterium. p. syringae also produces the algl-encoded alginate lyase, which cleaves the alginate biopolymer via a beta-elimination reaction. the algl gene from p. syringae maps to a 1134 bp region within the alginate biosynthetic operon, and is similar to algl from halomonas marina, p. aeruginosa, azotobacter chroococcum, and a. vinelandii. algl from p. syr ...	2001	11913796
expression profile matrix of arabidopsis transcription factor genes suggests their putative functions in response to environmental stresses.	numerous studies have shown that transcription factors are important in regulating plant responses to environmental stress. however, specific functions for most of the genes encoding transcription factors are unclear. in this study, we used mrna profiles generated from microarray experiments to deduce the functions of genes encoding known and putative arabidopsis transcription factors. the mrna levels of 402 distinct transcription factor genes were examined at different developmental stages and ...	2002	11910004
multilocus enzyme electrophoresis analysis of pseudomonas syringae pv. phaseolicola.	a multilocus enzyme electrophoresis technique was developed to detect variation in seven enzyme loci among isolates of pseudomonas syringae pv. phaseolicola, representing three races from different geographical locations, the causal agent of the halo blight disease of beans. cellulose acetate gel electrophoresis of seven enzymes revealed 19 electrotypes (et) among 21 pseudomonas syringae pv. phaseolicola isolates. one of the pathovar syringae and one of the pathovar tomato isolates were represen ...	2001	11899466
benzothiadiazole-induced priming for potentiated responses to pathogen infection, wounding, and infiltration of water into leaves requires the npr1/nim1 gene in arabidopsis.	systemic acquired resistance (sar) is a plant defense state that is induced, for example, after previous pathogen infection or by chemicals that mimic natural signaling compounds. sar is associated with the ability to induce cellular defense responses more rapidly and to a greater degree than in noninduced plants, a process called "priming." arabidopsis plants were treated with the synthetic sar inducer benzothiadiazole (bth) before stimulating two prominent cellular defense responses, namely ph ...	2002	11891259
snakin-2, an antimicrobial peptide from potato whose gene is locally induced by wounding and responds to pathogen infection.	the peptide snakin-2 (stsn2) has been isolated from potato (solanum tuberosum cv jaerla) tubers and found to be active (ec(50) = 1-20 microm) against fungal and bacterial plant pathogens. it causes a rapid aggregation of both gram-positive and gram-negative bacteria. the corresponding stsn2 cdna encodes a signal sequence followed by a 15-residue acidic sequence that precedes the mature stsn2 peptide, which is basic (isoelectric point = 9.16) and 66 amino acid residues long (molecular weight of 7 ...	2002	11891250
age-related resistance in arabidopsis is a developmentally regulated defense response to pseudomonas syringae.	age-related resistance (arr) has been observed in a number of plant species; however, little is known about the biochemical or molecular mechanisms involved in this response. arabidopsis becomes more resistant, or less susceptible, to virulent pseudomonas syringae (pv tomato or maculicola) as plants mature (in planta bacterial growth reduction of 10- to 100-fold). an arr-like response also was observed in response to certain environmental conditions that accelerate arabidopsis development. arr o ...	2002	11884688
large-scale structure-function analysis of the arabidopsis rpm1 disease resistance protein.	the arabidopsis rpm1 gene confers resistance against pseudomonas syringae expressing either the avrrpm1 or the avrb type iii effector protein. we present an exhaustive genetic screen for mutants that no longer recognize avrrpm1. using an inducible avrrpm1 expression system, we identified 110 independent mutations. these mutations represent six complementation groups. none discriminates between avrrpm1 and avrb recognition. we identified 95 rpm1 alleles and present a detailed structure--function ...	2002	11884685
distribution of spontaneous mutants and inferences about the replication mode of the rna bacteriophage phi6.	when a parent virus replicates inside its host, it must first use its own genome as the template for replication. however, once progeny genomes are produced, the progeny can in turn act as templates. depending on whether the progeny genomes become templates, the distribution of mutants produced by an infection varies greatly. while information on the distribution is important for many population genetic models, it is also useful for inferring the replication mode of a virus. we have analyzed the ...	2002	11884552
characterization of the replicator region of megaplasmid ptav3 of paracoccus versutus and search for plasmid-encoded traits.	the replicon of the ptav3 megaplasmid (approx. 400 kb) of paracoccus versutus has been localized to a 4center dot3 kb ecori restriction fragment and its entire nucleotide sequence determined. the g+c content of the entire sequence is 66 mol%, which is within the range (62-66 mol%) previously determined for p. versutus total dna. orf1 encodes a replication initiation protein rep (47.2 kda), which shares substantial similarity with putative proteins of the coxiella burnetii plasmids qph1 and qpdv, ...	2002	11882723
expression of a crown gall biological control phenotype in an avirulent strain of agrobacterium vitis by addition of the trifolitoxin production and resistance genes.	agrobacterium vitis is a causal agent of crown-gall disease. trifolitoxin (tfx) is a peptide antibiotic active only against members of a specific group of alpha-proteobacteria that includes agrobacterium and its close relatives. the ability of tfx production by an avirulent strain of agrobacterium to reduce crown gall disease is examined here.	2002	11882255
alpha-crystallin-type heat shock proteins: socializing minichaperones in the context of a multichaperone network.	alpha-crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. subsequently, they have been found in many, but not all, members of the archaea, bacteria, and eucarya. most members of the diverse alpha-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kda; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the ...	2002	11875128
a functional screen for the type iii (hrp) secretome of the plant pathogen pseudomonas syringae.	type iii secreted "effector" proteins of bacterial pathogens play central roles in virulence, yet are notoriously difficult to identify. we used an in vivo genetic screen to identify 13 effectors secreted by the type iii apparatus (called hrp, for "hypersensitive response and pathogenicity") of the plant pathogen pseudomonas syringae. although sharing little overall homology, the amino-terminal regions of these effectors had strikingly similar amino acid compositions. this feature facilitated th ...	2002	11872842
phenotypic selection and phase variation occur during alfalfa root colonization by pseudomonas fluorescens f113.	during colonization of the alfalfa rhizosphere, pseudomonas fluorescens f113 undergoes phenotypic variation, resulting in the appearance of colonies with different morphology. among phenotypic variants, three isolates, c, f, and s were selected, with the c variant showing colony morphology identical to that of the inoculated wild-type strain and f and s having a translucent and diffuse morphology. phenotypic variants f and s were shown to preferentially colonize distal parts of the roots and sho ...	2002	11872710
reduction of olive knot disease by a bacteriocin from pseudomonas syringae pv. ciccaronei.	a bacteriocin produced by pseudomonas syringae pv. ciccaronei, used at different purification levels and concentrations in culture and in planta, inhibited the multiplication of p. syringae subsp. savastanoi, the causal agent of olive knot disease, and affected the epiphytic survival of the pathogen on the leaves and twigs of treated olive plants. treatments with bacteriocin from p. syringae pv. ciccaronei inhibited the formation of overgrowths on olive plants caused by p. syringae subsp. savast ...	2002	11872493
effects of t4 lysozyme release from transgenic potato roots on bacterial rhizosphere communities are negligible relative to natural factors.	rhizosphere bacterial communities of two transgenic potato lines which produce t4 lysozyme for protection against bacterial infections were analyzed in comparison to communities of wild-type plants and transgenic controls not harboring the lysozyme gene. rhizosphere samples were taken from young, flowering, and senescent plants at two field sites in three consecutive years. the communities were characterized in a polyphasic approach. cultivation-dependent methods included heterotrophic plate cou ...	2002	11872484
crystal structure and electron transfer kinetics of cueo, a multicopper oxidase required for copper homeostasis in escherichia coli.	cueo (yack), a multicopper oxidase, is part of the copper-regulatory cue operon in escherichia coli. the crystal structure of cueo has been determined to 1.4-a resolution by using multiple anomalous dispersion phasing and an automated building procedure that yielded a nearly complete model without manual intervention. this is the highest resolution multicopper oxidase structure yet determined and provides a particularly clear view of the four coppers at the catalytic center. the overall structur ...	2002	11867755
esa1, an arabidopsis mutant with enhanced susceptibility to a range of necrotrophic fungal pathogens, shows a distorted induction of defense responses by reactive oxygen generating compounds.	an arabidopsis thaliana mutant, esa1, that shows enhanced susceptibility to the necrotrophic pathogens alternaria brassicicola, botrytis cinerea and plectosphaerella cucumerina, but has wild-type levels of resistance to the biotrophic pathogens pseudomonas syringae pv. tomato and peronospora parasitica. the enhanced susceptibility towards necrotrophic pathogens correlated with a delayed induction of phytoalexin accumulation and delayed induction of the plant defensin gene pdf1.2 upon inoculation ...	2002	11862946
mrna stability and the secretion signal of hrpa, a pilin secreted by the type iii system in pseudomonas syringae.	gram-negative bacteria that are pathogenic for animals or plants utilise a specialised type iii secretion system to inject effector proteins into their eukaryotic target cells. the basis for selection of the proteins to be translocated via type iii systems is still enigmatic. no clearly defined consensus amino acid sequence that could serve as a specific secretion signal has been identified, and the hypothesis that an mrna secondary structure acts as the signal has several shortcomings. we have ...	2002	11862491
infection of arabidopsis with a necrotrophic pathogen, botrytis cinerea, elicits various defense responses but does not induce systemic acquired resistance (sar).	botrytis cinerea is a non-specific necrotrophic pathogen that attacks more than 200 plant species. in contrast to biotrophs, the necrotrophs obtain their nutrients by first killing the host cells. many studies have shown that infection of plants by necrosis-causing pathogens induces a systemic acquired resistance (sar), which provides protection against successive infections by a range of pathogenic organisms. we analyzed the role of sar in b. cinerea infection of arabidopsis. we show that altho ...	2002	11855728
genomewide identification of pseudomonas syringae pv. tomato dc3000 promoters controlled by the hrpl alternative sigma factor.	the ability of pseudomonas syringae pv. tomato dc3000 to parasitize tomato and arabidopsis thaliana depends on genes activated by the hrpl alternative sigma factor. to support various functional genomic analyses of dc3000, and specifically, to identify genes involved in pathogenesis, we developed a draft sequence of dc3000 and used an iterative process involving computational and gene expression techniques to identify virulence-implicated genes downstream of hrpl-responsive promoters. hypersensi ...	2002	11854524
two novel type iii-secreted proteins of xanthomonas campestris pv. vesicatoria are encoded within the hrp pathogenicity island.	the hrp type iii protein secretion system (ttss) is essential for pathogenicity of gram-negative plant pathogen xanthomonas campestris pv. vesicatoria. cdna-amplified fragment length polymorphism and reverse transcription-pcr analyses identified new genes, regulated by key hrp regulator hrpg, in the regions flanking the hrp gene cluster. sequence analysis revealed genes encoding hpag, a predicted leucine-rich repeat-containing protein, the lysozyme-like hpah protein, and xopa and xopd, which are ...	2002	11844763
characterization of the sala, syrf, and syrg regulatory genes located at the right border of the syringomycin gene cluster of pseudomonas syringae pv. syringae.	sequence analysis of the right border of the syr gene cluster of pseudomonas syringae pv. syringae strain b301d revealed the presence of the sala gene 8,113 bp downstream of syre. the predicted sala protein of strain b301d differs by one amino acid from that of strain b728a. two homologs of sala, designated syrf and syrg, were identified between syre and sala. all three proteins contain helix-turn-helix dna-binding motifs at their c termini and exhibit homology to regulatory proteins of the luxr ...	2002	11843302
milestones in chloroplast genetic engineering: an environmentally friendly era in biotechnology.	chloroplast genomes defied the laws of mendelian inheritance at the dawn of plant genetics, and continue to defy the mainstream approach to biotechnology, leading the field in an environmentally friendly direction. recent success in engineering the chloroplast genome for resistance to herbicides, insects, disease and drought, and for production of biopharmaceuticals, has opened the door to a new era in biotechnology. the successful engineering of tomato chromoplasts for high-level transgene expr ...	2002	11832280
eds5, an essential component of salicylic acid-dependent signaling for disease resistance in arabidopsis, is a member of the mate transporter family.	the eds5 mutant of arabidopsis (earlier named sid1) was shown previously to accumulate very little salicylic acid and pr-1 transcript after pathogen inoculation and to be hypersusceptible to pathogens. we have isolated eds5 by positional cloning and show that it encodes a protein with a predicted series of nine to 11 membrane-spanning domains and a coil domain at the n terminus. eds5 is homologous with members of the mate (multidrug and toxin extrusion) transporter family. eds5 expression is ver ...	2002	11826312
bacteria associated with hazelnut (corylus avellana l.) decline are of two groups: pseudomonas avellanae and strains resembling p. syringae pv. syringae.	a total of 118 fluorescent pseudomonads associated with hazelnut decline, which has been occurring for many years in different areas of northern greece and italy, were assessed by performing a repetitive pcr analysis with enterobacterial repetitive intergenic consensus, box element, and repetive extragenic palindromic primer sets, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of whole-cell protein extracts, a carbon compound utilization analysis, and an analysis to determi ...	2002	11823181
regulatory rna as mediator in gaca/rsma-dependent global control of exoproduct formation in pseudomonas fluorescens cha0.	in pseudomonas fluorescens cha0, an antagonist of root-pathogenic fungi, the gacs/gaca two-component system tightly controls the expression of antifungal secondary metabolites and exoenzymes at a posttranscriptional level, involving the rna-binding protein and global regulator of secondary metabolism rsma. this protein was purified from p. fluorescens, and rna bound to it was converted to cdna, which served as a probe to isolate the corresponding chromosomal locus, rsmz. this gene encoded a regu ...	2002	11807065
epigenetic variation in arabidopsis disease resistance.	plant pathogen resistance is mediated by a large repertoire of resistance (r) genes, which are often clustered in the genome and show a high degree of genetic variation. here, we show that an arabidopsis thaliana r-gene cluster is also subject to epigenetic variation. we describe a heritable but metastable epigenetic variant bal that overexpresses the r-like gene at4g16890 from a gene cluster on chromosome 4. the bal variant and arabidopsis transgenics overexpressing the at4g16890 gene are dwarf ...	2002	11799061
the arabidopsis xylem peptidase xcp1 is a tracheary element vacuolar protein that may be a papain ortholog.	xcp1 is a xylem-specific papain-like cysteine peptidase in arabidopsis. to determine whether xcp1 could be involved in tracheary element autolysis, promoter activity and localization of xcp1 were investigated using xcp1 promoter-beta-glucuronidase fusions and immunofluorescence confocal microscopy. a tracheary element expression pattern was detected for xcp1. results from confocal microscopy and biochemical subcellular fractionation indicated that xcp1 was localized in the vacuole. ectopic expre ...	2002	11788755
functional analysis of tomato pti4 in arabidopsis.	pti4 is a tomato (lycopersicon esculentum) transcription factor that belongs to the erf (ethylene-responsive element binding factor) family of proteins. it interacts with the pto kinase in tomato, which confers resistance to the pseudomonas syringae pv tomato pathogen that causes bacterial speck disease. to study the function of pti4, transgenic arabidopsis plants were generated that expressed tomato pti4 driven by the strong constitutive promoters, cauliflower mosaic virus 35s and tcup. global ...	2002	11788750
an oligopeptide transporter gene family in arabidopsis.	we have identified nine oligopeptide transporter (opt) orthologs (atopt1 to atopt9) in arabidopsis. these proteins show significant sequence similarity to opts of candida albicans (caopt1p), schizosaccharomyces pombe (isp4p), and saccharomyces cerevisiae (opt1p and opt2p). hydrophilicity plots of the opts suggest that they are integral membrane proteins with 12 to 14 transmembrane domains. sequence comparisons showed that the atopts form a distinct subfamily when compared with the fungal opts. t ...	2002	11788749
[epiphytic phase of erwinia amylovora and pseudomonas syringae pv. syringae on orchard weeds].	epiphyte phase of phytopathogenic bacteria erwinia amylovora and pseudomonas syringae pv. syringae on the fruit garden weeds has been studied. it has been shown that healthy weeds of the fruit-tree stands can be an ecologic niche for erwinia amylovora and pseudomonas syringae pv. syringae which gives them an opportunity to survive as epiphytes. strains of pseudomonas syringae pv. syringae were isolated from seven studied weeds (47-49%) during the whole vegetation period (march-october). strains ...	2001	11785263
identification of the 2-methylcitrate pathway involved in the catabolism of propionate in the polyhydroxyalkanoate-producing strain burkholderia sacchari ipt101(t) and analysis of a mutant accumulating a copolyester with higher 3-hydroxyvalerate content.	burkholderia sacchari ipt101(t) induced the formation of 2-methylcitrate synthase and 2-methylisocitrate lyase when it was cultivated in the presence of propionic acid. the prp locus of b. sacchari ipt101(t) is required for utilization of propionic acid as a sole carbon source and is relevant for incorporation of 3-hydroxyvalerate (3hv) into copolyesters, and it was cloned and sequenced. five genes (prpr, prpb, prpc, acnm, and orf5) exhibited identity to genes located in the prp loci of other gr ...	2002	11772636
cloning, sequencing, and expression of the cold-inducible hutu gene from the antarctic psychrotrophic bacterium pseudomonas syringae.	a promoter-fusion study with a tn 5-based promoter probe vector had earlier found that the hutu gene which encodes the enzyme urocanase for the histidine utilization pathway is upregulated at a lower temperature (4 degrees c) in the antarctic psychrotrophic bacterium pseudomonas syringae. to examine the characteristics of the urocanase gene and its promoter elements from the psychrotroph, the complete hutu and its upstream region from p. syringae were cloned, sequenced, and analyzed in the prese ...	2002	11772602
overexpression of pti5 in tomato potentiates pathogen-induced defense gene expression and enhances disease resistance to pseudomonas syringae pv. tomato.	the tomato pti5 gene encodes a pathogen-inducible ethylene response element-binding protein-like transcription factor that interacts with the disease resistance gene product pto. overexpression of pti5 or pti5-vp16, a translational fusion with a constitutive transcriptional activation domain, in tomato enhanced resistance to pseudomonas syringae pv. tomato. constitutive expression of pti5 or pti5-vp16 did not affect the basal level of pathogenesis-related gene expression, but it accelerated path ...	2001	11768541
a physical map of the syringomycin and syringopeptin gene clusters localized to an approximately 145-kb dna region of pseudomonas syringae pv. syringae strain b301d.	genetic and phenotypic mapping of an approximately 145-kb drai fragment of pseudomonas syringae pv. syringae strain b301d determined that the syringomycin (syr) and syringopeptin (syp) gene clusters are localized to this fragment. the syr and syp gene clusters encompass approximately 55 kb and approximately 80 kb, respectively. both phytotoxins are synthesized by a thiotemplate mechanism of biosynthesis, requiring large multienzymatic proteins called peptide synthetases. genes encoding peptide s ...	2001	11768538
genetic divergence in the algt-muc operon controlling alginate biosynthesis and response to environmental stress in pseudomonas syringae.	the algt-muc gene cluster (rpoe operon) is important for alginate production and survival during environmental stress in pseudomonas syringae. the algt-muc operon was cloned and sequenced from p. syringae to determine whether the organization of this gene cluster was conserved in this plant pathogen. interestingly, analysis of the algt-muc region in p. syringae revealed a unique arrangement when compared to other bacteria and lacked a mucc homologue. the relative importance of the mucc gene in t ...	2001	11761711
[ecological factors affecting prevalence of kiwifruit bacterial canker and bacteriostatic action of bacteriocides on pseudomonas syringae pv. actinidae].	according to the systematic study for 5 years, this paper dealt with the ecological factors affecting prevalence of kiwifruit bacterial canker. the disease was more serious in the orchards with above 750 m in elevation, and more serious at mountain slope facing south than facing north. incidence differed significantly among cultivars, with easy disease infection for jinfeng, and strong disease resistance for jinkui. the older the trees, the more the diseased plants. the one year old twigs had hi ...	2001	11758413
[prevalent forecast of kiwifruit bacterial canker caused by pseudomonas syringae pv. actinidiae].	the prevalent analysis of kiwifruit bacterial canker for several years showed that the effective ecological factors of severe degree were the precipitation (x1) in the second and last ten-days of march, and the average temperature (x2) of january. the model was y = 2.1359 + 0.0107x1 - 0.6061x2. the main factor of the prevalence was the relative variation of ten-days average temperature and precipitation in winter and in early spring, and the regression equation was y = -8.127 + 22.739x - 13.254x ...	2001	11758412
arabidopsis gp91phox homologues atrbohd and atrbohf are required for accumulation of reactive oxygen intermediates in the plant defense response.	reactive oxygen intermediates (roi) are strongly associated with plant defense responses. the origin of these roi has been controversial. arabidopsis respiratory burst oxidase homologues (rboh genes) have been proposed to play a role in roi generation. we analyzed lines carrying dspm insertions in the highly expressed atrbohd and atrbohf genes. both are required for full roi production observed during incompatible interactions with the bacterial pathogen pseudomonas syringae pv. tomato dc3000(av ...	2002	11756663
arabidopsis gp91phox homologues atrbohd and atrbohf are required for accumulation of reactive oxygen intermediates in the plant defense response.	reactive oxygen intermediates (roi) are strongly associated with plant defense responses. the origin of these roi has been controversial. arabidopsis respiratory burst oxidase homologues (rboh genes) have been proposed to play a role in roi generation. we analyzed lines carrying dspm insertions in the highly expressed atrbohd and atrbohf genes. both are required for full roi production observed during incompatible interactions with the bacterial pathogen pseudomonas syringae pv. tomato dc3000(av ...	2002	11756663
role of the hrp pilus in type iii protein secretion in pseudomonas syringae.	bacterial surface appendages called pili and needle-like filaments are associated with protein and/or dna transfer to recipient plant, human, or bacterial cells during pathogenesis or conjugation. although it has long been suspected that pili function as a conduit for protein or dna transfer, direct evidence has been lacking. the hrp pilus of pseudomonas syringae is assembled by the type iii secretion system. we used an in situ immunogold labeling procedure to visualize the extrusion of an effec ...	2001	11752577
monitoring the switch from housekeeping to pathogen defense metabolism in arabidopsis thaliana using cdna arrays.	plants respond to pathogen attack by deploying several defense reactions. some rely on the activation of preformed components, whereas others depend on changes in transcriptional activity. using cdna arrays comprising 13,000 unique expressed sequence tags, changes in the transcriptome of arabidopsis thaliana were monitored after attempted infection with the bacterial plant pathogen pseudomonas syringae pv. tomato carrying the avirulence gene avrrpt2. sampling at four time points during the first ...	2002	11748215
the matrix metalloproteinase gene gmmmp2 is activated in response to pathogenic infections in soybean.	matrix metalloproteinases (mmps) play an important role in host defense responses against pathogens in mammals where their activities lead to the production of antimicrobial peptides. we have identified a novel soybean (glycine max) metalloproteinase gene, gmmmp2, that is transcriptionally up-regulated in infected tissues. the deduced amino acid sequence indicates that this gene belongs to the mmp family. it is a preproprotein containing an n-terminal signal peptide, a cysteine switch, a zinc-bi ...	2001	11743122
tox-boxes, fungal secondary metabolites, and plant disease.		2001	11734635
the role of bacterial pili in protein and dna translocation.	gram-negative bacteria have surface appendages that assemble via different secretion machineries. recently, new experimental approaches have contributed to a better understanding of the molecular mechanisms of flagellar and pilus assembly, and protein secretion. these findings can be applied to plant pathogenic bacteria, which probably transfer effector proteins directly into their eukaryotic host cells. here, it is suggested that assembly of hrp pili occurs in the periplasm and that unfolded ef ...	2001	11728871
structural heterogeneity in the lipopolysaccharides of pseudomonas syringae with o-polysaccharide chains having different repeating units.	studies by sugar and methylation analyses, smith degradation, and 1h and 13c nmr spectroscopy revealed a structural heterogeneity in the o-polysaccharides of pseudomonas syringae pvs. coronafaciens imv 9030 and atrofaciens imv 8281 owing to the presence of different types of repeating units. in strain imv 9030, the major repeating units are a linear alpha-l-rhamnose trisaccharide and a tetrasaccharide (a, n=0 or 1). a minor repeating unit is a branched pentasaccharide with an alpha-l-rhamnose ma ...	2001	11728403
the structure of the pyoverdin isolated from various pseudomonas syringae pathovars.	from seven different pathovars of pseudomonas syringae representing various genetic subgroups, and one strain of pseudomonas viridiflava the same pyoverdin siderophore (1) was isolated, probably identical with the pyoverdin whose amino acid composition (but not their sequence) had been reported before. 1 is the first pyoverdin where two of the ligands for fe3+ are beta-hydroxy asp units. its remarkably high complexing constant for fe3+ at ph 5 as compared with other pyoverdins offers a definite ...	2001	11724369
the sigma factor algu (algt) controls exopolysaccharide production and tolerance towards desiccation and osmotic stress in the biocontrol agent pseudomonas fluorescens cha0.	a variety of stress situations may affect the activity and survival of plant-beneficial pseudomonads added to soil to control root diseases. this study focused on the roles of the sigma factor algu (synonyms, algt, rpoe, and sigma(22)) and the anti-sigma factor muca in stress adaptation of the biocontrol agent pseudomonas fluorescens cha0. the algu-muca-mucb gene cluster of strain cha0 was similar to that of the pathogens pseudomonas aeruginosa and pseudomonas syringae. strain cha0 is naturally ...	2001	11722923
effect of solar uv-b radiation on a phyllosphere bacterial community.	the effect of solar uv-b radiation on the population dynamics and composition of the culturable bacterial community from peanut (arachis hypogeae l.) was examined in field studies using plants grown under uv-b-transmitting (uv-b+) or uv-b-excluding (uv-b-) plastic filters. our data demonstrate that solar uv-b selection alters phyllosphere bacterial community composition and that uv tolerance is a prevalent phenotype late in the season. the total bacterial population size was not affected by eith ...	2001	11722897
display of passenger proteins on the surface of escherichia coli k-12 by the enterohemorrhagic e. coli intimin eaea.	intimins are members of a family of bacterial adhesins from pathogenic escherichia coli which specifically interact with diverse eukaryotic cell surface receptors. the eaea intimin from enterohemorrhagic e. coli o157:h7 contains an n-terminal transporter domain, which resides in the bacterial outer membrane and promotes the translocation of four c-terminally attached passenger domains across the bacterial cell envelope. we investigated whether truncated eaea intimin lacking two carboxy-terminal ...	2001	11717287
hydrogen peroxide fluxes and compartmentalization inside growing escherichia coli.	escherichia coli generates about 14 microm hydrogen peroxide (h(2)o(2)) per s when it grows exponentially in glucose medium. the steady-state intracellular concentration of h(2)o(2) depends on the rates at which this h(2)o(2) is dissipated by scavenging enzymes and by efflux from the cell. the rates of h(2)o(2) degradation by the two major scavenging enzymes, alkyl hydroperoxide reductase and catalase, were quantified. in order to estimate the rate of efflux, the permeability coefficient of memb ...	2001	11717277
differential roles of the pseudomonas aeruginosa pa14 rpon gene in pathogenicity in plants, nematodes, insects, and mice.	we cloned the rpon (ntra, glnf) gene encoding the alternate sigma factor sigma(54) from the opportunistic multihost pathogen pseudomonas aeruginosa strain pa14. a marker exchange protocol was used to construct the pa14 rpon insertional mutation rpon::gen(r). pa14 rpon::gen(r) synthesized reduced levels of pyocyanin and displayed a variety of phenotypes typical of rpon mutants, including a lack of motility and the failure to grow on nitrate, glutamate, or histidine as the sole nitrogen source. co ...	2001	11717271
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
an off-line implementation of the stable isotope technique for measurements of alternative respiratory pathway activities.	in situ measurements of alternative respiratory pathway activity are needed to provide insight into the energy efficiency of plant metabolism under various conditions in the field. the only reliable method at present to measure alternative oxidase (aox) activity is through measurement of changes in delta(18)o(o(2)), which to date has only been used in laboratory environments. we have developed a cuvette system to measure partitioning of electrons to aox that is suitable for off-line use and for ...	2001	11706206
the role of ndr1 in avirulence gene-directed signaling and control of programmed cell death in arabidopsis.	arabidopsis plants containing the ndr1-1 mutation are incapable of mounting a hypersensitive response to bacteria carrying avrrpt2, but show an exaggerated cell death response to bacteria carrying avrb (century et al., 1995). we show here that ndr1-1 plants are severely impaired in induction of systemic acquired resistance and pr1-driven transcription of a reporter gene in response to pseudomonas syringae strains carrying avrrpt2 but not in response to p. syringae carrying avrb. the ndr1-1 mutat ...	2001	11706189
expression of an antimicrobial peptide via the chloroplast genome to control phytopathogenic bacteria and fungi.	the antimicrobial peptide msi-99, an analog of magainin 2, was expressed via the chloroplast genome to obtain high levels of expression in transgenic tobacco (nicotiana tabacum var. petit havana) plants. polymerase chain reaction products and southern blots confirmed integration of msi-99 into the chloroplast genome and achievement of homoplasmy, whereas northern blots confirmed transcription. contrary to previous predictions, accumulation of msi-99 in transgenic chloroplasts did not affect norm ...	2001	11706168
a novel protein elicitor (panie) from pythium aphanidermatum induces multiple defense responses in carrot, arabidopsis, and tobacco.	a novel protein elicitor (panie(234)) from pythium aphanidermatum (edson) fitzp. was purified, microsequenced, and the corresponding cdna was cloned. the deduced amino acid sequence contains a putative eukaryotic secretion signal with a proteinase cleavage site. the heterologously expressed elicitor protein without the secretion signal of 21 amino acids (panie(213)) triggered programmed cell death and de novo formation of 4-hydroxybenzoic acid in cultured cells of carrot (daucus carota). program ...	2001	11706166