Publications

composition of soil microbial communities enriched on a mixture of aromatic hydrocarbons.	soil contaminated with c5+, which contained benzene (45%, wt/wt), dicyclopentadiene (dcpd) plus cyclopentadiene (together 20%), toluene (6%), styrene (3%), xylenes (2%), naphthalene (2%), and smaller quantities of other compounds, served as the source for isolation of 55 genomically distinct bacteria (standards). use of benzene as a substrate by these bacteria was most widespread (31 of 44 standards tested), followed by toluene (23 of 44), xylenes (14 of 44), styrene (10 of 44), and naphthalene ...	2000	11097903
functional tn5393-like transposon in the r plasmid pras2 from the fish pathogen aeromonas salmonicida subspecies salmonicida isolated in norway.	tn5393c containing stra-strb was identified as part of r plasmid pras2 from the fish pathogen aeromonas salmonicida subsp. salmonicida. this is the first time an intact and active transposon in the tn5393 family has been reported in an ecological niche other than an agricultural habitat.	2000	11097945
xv4-vrxv4: a new gene-for-gene interaction identified between xanthomonas campestris pv. vesicatoria race t3 and wild tomato relative lycopersicon pennellii.	strains of tomato race 3 (t3) of xanthomonas campestris pv. vesicatoria elicit a hypersensitive response (hr) in leaves of lycopersicon pennellii la716. genetic segregation of the resistance exhibited ratios near 3:1 in f2 populations, which confirmed that a single dominant gene controlled the inheritance of this trait. with the aid of a collection of introgression lines, restriction fragment length polymorphism, and cleaved amplified polymorphic sequence markers, the resistance locus was locate ...	2000	11106027
resistance of tomato and pepper to t3 strains of xanthomonas campestris pv. vesicatoria is specified by a plant-inducible avirulence gene.	tomato race 3 (t3) of xanthomonas campestris pv. vesicatoria (xcv) elicits a hypersensitive response (hr) in leaves of lycopersicon esculentum near-isogenic line (nil) 216 and pepper genotypes. one cosmid clone (35 kb) selected from a genomic library of a t3 strain induced an hr in all resistant plants. a 1.5-kb active subclone containing the putative avirulence (avr) gene, designated avrxv3, was sequenced. the avrxv3 gene encodes a 654-bp open reading frame (orf) with no homology to any known g ...	2000	10975648
in vitro antimicrobial properties of recombinant asabf, an antimicrobial peptide isolated from the nematode ascaris suum.	asabf is a csalphabeta-type antimicrobial peptide that contains four intramolecular disulfide bridges (y. kato and s. komatsu, j. biol. chem. 271:30493-30498, 1996). in the present study, a recombinant asabf was produced by using a yeast expression system, and its antimicrobial activity was characterized in detail. the recombinant asabf was active against all gram-positive bacteria tested (7 of 7; minimum bactericidal concentration [mbc], 0.03 to 1 microg/ml) except leuconostoc mesenteroides, so ...	2000	10991847
molecular and physiological analysis of an oxyr-regulated ahpc promoter in xanthomonas campestris pv. phaseoli.	in xanthomonas campestris pv. phaseoli, a gene for the alkyl hydroperoxide reductase subunit c (ahpc) had unique patterns of regulation by various forms of oxyr. reduced oxyr repressed expression of the gene, whereas oxidized oxyr activated its expression. this dual regulation of ahpc is unique and unlike all other oxyr-regulated genes. the ahpc transcription start site was determined. analysis of the region upstream of the site revealed promoter sequences that had high homology to the xanthomon ...	2000	10998180
identification of essential amino acids in the bacterial alpha -mannosyltransferase acea.	the alpha-mannosyltransferase acea from acetobacter xylinum belongs to the cazy family 4 of retaining glycosyltransferases. we have identified a series of either highly conserved or invariant residues that are found in all family 4 enzymes as well as other retaining glycosyltransferases. these residues included glu-287 and glu-295, which comprise an ex(7)e motif and have been proposed to be involved in catalysis. alanine replacements of each conserved residue were constructed by site-directed mu ...	2000	11001941
leafy gall formation is controlled by fasr, an arac-type regulatory gene in rhodococcus fascians.	rhodococcus fascians can interact with many plant species and induce the formation of either leafy galls or fasciations. to provoke symptoms, r. fascians strain d188 requires pathogenicity genes that are located on a linear plasmid, pfid188. the fas genes are essential for virulence and constitute an operon that encodes, among other functions, a cytokinin synthase gene. expression of the fas genes is induced by extracts of infected plant tissue only. we have isolated an arac-type regulatory gene ...	2000	11004184
identification of a copper-responsive two-component system on the chromosome of escherichia coli k-12.	using a genetic screen we have identified two chromosomal genes, cusrs (ylca ybcz), from escherichia coli k-12 that encode a two-component, signal transduction system that is responsive to copper ions. this regulatory system is required for copper-induced expression of pcoe, a plasmid-borne gene from the e. coli copper resistance operon pco. the closest homologs of cusr and cuss are plasmid-borne two-component systems that are also involved in metal responsive gene regulation: pcor and pcos from ...	2000	11004187
pcr assays that identify the grapevine dieback fungus eutypa lata.	eutypa lata is the causal fungal agent of eutypa dieback, a serious grapevine necrotic disease. the erratic and delayed (1 to 2 months) appearance of characteristic conidia on culture media and the presence of numerous microorganisms in decaying wood make it difficult either to identify or to detect e. lata in grapevine wood samples. we designed six pairs of pcr primers for diagnosis of e. lata. three primer pairs were derived from ribosomal dna internal transcribed spacer sequences, and three p ...	2000	11010901
pepper gene encoding a basic class ii chitinase is inducible by pathogen and ethephon.	a chitinase cdna clone (designated cachi2) was isolated from the cdna library of pepper leaves infected with xanthomonas campestris pv. vesicatoria. the 1004-bp full-length cachi2 cdna encodes a basic chitinase with an n-terminal 24 amino acid signal peptide followed by a catalytic region. an analysis of its sequence indicates that cachi2 is a class ii chitinase, because it does not have chitin-binding domain and c-terminal extension sequences. the deduced amino acid sequence of cachi2 has a hig ...	2000	11011091
pepper gene encoding a basic beta-1,3-glucanase is differentially expressed in pepper tissues upon pathogen infection and ethephon or methyl jasmonate treatment.	a basic beta-1,3-glucanase cdna clone (cabglu) was isolated from the cdna library constructed from hypersensitive response lesions of pepper leaves infected with avirulent strain of xanthomonas campestris pv. vesicatoria. the deduced polypeptide of cabglu which contains a c-terminal extension n-glycosylated at a single site characterized as typical structure of class i beta-1,3-glucanase has a high level of identity with tobacco basic beta-1,3-glucanase (77.4%), but only a moderate level of iden ...	2000	11011097
intracellular glucosaminidase of the bacterium xanthomonas campestris ibpm b-124: purification and properties.	a system of intracellular autolytic enzymes of the bacterium xanthomonas campestris ibpm b-124 was found to include enzymes with muramidase and glucosaminidase activities, while a system of extracellular bacteriolytic enzymes of the same bacterium includes muramidase, muramoylalanine amidase, and endopeptidase. using a purification technique including fractional precipitation with ammonium sulfate, gel-filtration on toyopearl hw-55f, and fplc ion-exchange chromatography on mono q, a preparation ...	2000	11042495
o-specific polysaccharide structure of the aqueous lipopolysaccharide fraction from xanthomonas campestris pv. vitians strain 1839.	the structure of xanthomonas campestris pv. vitians o-specific polysaccharide of the lipopolysaccharide fraction, extracted from the aqueous phase, was defined, on the basis of chemical and spectroscopical methods, as constituted by the following repeating unit: [--> 3)-alpha-l-rhap-(1 -->]n 3)-beta-l-rhap-(1 --> where n is more frequently equal to 2, but it also assumes values equal to 1 and to 3.	2000	11072852
s-adenosylmethionine decarboxylase from the archaeon methanococcus jannaschii: identification of a novel family of pyruvoyl enzymes.	polyamines are present in high concentrations in archaea, yet little is known about their synthesis, except by extrapolation from bacterial and eucaryal systems. s-adenosylmethionine (adomet) decarboxylase, a pyruvoyl group-containing enzyme that is required for spermidine biosynthesis, has been previously identified in eucarya and escherichia coli. despite spermidine concentrations in the methanococcales that are several times higher than in e. coli, no adomet decarboxylase gene was recognized ...	2000	11073910
a xanthomonas alkyl hydroperoxide reductase subunit c (ahpc) mutant showed an altered peroxide stress response and complex regulation of the compensatory response of peroxide detoxification enzymes.	alkyl hydroperoxide reductase subunit c (ahpc) is the catalytic subunit responsible for alkyl peroxide metabolism. a xanthomonas ahpc mutant was constructed. the mutant had increased sensitivity to organic peroxide killing, but was unexpectedly hyperresistant to h(2)o(2) killing. analysis of peroxide detoxification enzymes in this mutant revealed differential alteration in catalase activities in that its bifunctional catalase-peroxidase enzyme and major monofunctional catalase (kat1) increased s ...	2000	11073935
molecular signals required for type iii secretion and translocation of the xanthomonas campestris avrbs2 protein to pepper plants.	strains of xanthomonas campestris pv. vesicatoria (xcv) carrying avrbs2 are specifically recognized by bs2 pepper plants, resulting in localized cell death and plant resistance. agrobacterium-mediated transient expression of the xcv avrbs2 gene in plant cells results in bs2-dependent cell death, indicating that the avrbs2 protein alone is sufficient for the activation of disease resistance-mediated cell death in planta. we now provide evidence that avrbs2 is secreted from xcv and that secretion ...	2000	11078519
structure and sequence analysis of yersinia yada and moraxella uspas reveal a novel class of adhesins.	the non-fimbrial adhesins, yada of enteropathogenic yersinia species, and uspa1 and uspa2 of moraxella catarrhalis, are established pathogenicity factors. in electron micrographs, both surface proteins appear as distinct 'lollipop'-shaped structures forming a novel type of surface projection on the outer membranes. these structures, amino acid sequence analysis of these molecules and yada gene manipulation suggest a tripartite organization: an n-terminal oval head domain is followed by a putativ ...	2000	11080146
use of 16s rdna sequences as signature characters to identify xylella fastidiosa.	the nucleotide sequences of 16s rdnas (coding for the small subunit ribosomal rnas) were used to identify xylella fastidiosa, a nutritionally fastidious plant pathogenic bacterium. the near-complete 16s rdnas from nine strains of xyl. fastidiosa, including seven pathotypes and one strain of xanthomonas campestris pv. campestris, were amplified through pcr with two conserved primers (forward primer 5'-aga gtt tga tcc tgg ctc ag-3' and reverse primer 5'-aag gag gtg atc cag cc-3') and sequenced. th ...	2000	10568800
modified pyrogallol-initiated immunogold-silver enhancement technique applicable to prokaryotes.	a modified immunogold-silver enhancement technique that was designed to reduce the nonspecific granular background staining, particularly for application on prokaryotic organisms, is reported. aerial oxidation of pyrogallol contained in the commercial silver enhancer solution was effectively controlled during storage and in the reaction mixture. a combination of strategies such as storing the reagent under argon, modifying it using 0.5% (w/v) anhydrous sodium sulfite, reducing the concentration ...	2000	10958966
the redox-sensitive transcriptional activator oxyr regulates the peroxide response regulon in the obligate anaerobe bacteroides fragilis.	the peroxide response-inducible genes ahpcf, dps, and katb in the obligate anaerobe bacteroides fragilis are controlled by the redox-sensitive transcriptional activator oxyr. this is the first functional oxidative stress regulator identified and characterized in anaerobic bacteria. oxyr and dps were found to be divergently transcribed, with an overlap in their respective promoter regulatory regions. b. fragilis oxyr and dps proteins showed high identity to homologues from a closely related anaer ...	2000	10960088
characterization of the incw cryptic plasmid pxv2 from xanthomonas campestris pv. vesicatoria.	the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria strain xv2 harbors an indigenous, cryptic plasmid pxv2 of 14.6 kb. this plasmid can only be maintained in xanthomonas and is incapable of self-transmission. however, incompatibility testing classified it in incw, a group containing the smallest number of naturally occurring, broad-host-range, conjugative plasmids. a pxv2 derivative containing only a 5.5-kb psti fragment is stably maintained. deletion of a 3.0-kb region from ...	2000	10964626
a serine protease-encoding gene (aprii) of alteromonas sp. strain o-7 is regulated by the iron uptake regulator (fur) protein.	the ferric uptake regulator (fur) box-like sequence was located upstream of the serine protease-encoding gene (aprii) from a marine bacterium, alteromonas sp. strain o-7. to clarify whether the production of aprii (the gene product of aprii) is regulated by the environmental iron concentrations, this strain was cultured under iron-depleted or iron-rich conditions and the level of aprii in the culture supernatant was analyzed by western blotting. the production of aprii was significantly represse ...	2000	10966390
starvation improves survival of bacteria introduced into activated sludge.	a phenol-degrading bacterium, ralstonia eutropha e2, was grown in luria-bertani (lb) medium or in an inorganic medium (called mp) supplemented with phenol and harvested at the late-exponential-growth phase. phenol-acclimated activated sludge was inoculated with the e2 cells immediately after harvest or after starvation in mp for 2 or 7 days. the densities of the e2 populations in the activated sludge were then monitored by quantitative pcr. the e2 cells grown on phenol and starved for 2 days (p- ...	2000	10966407
a novel gene encoding xanthan lyase of paenibacillus alginolyticus strain xl-1.	xanthan-modifying enzymes are powerful tools in studying structure-function relationships of this polysaccharide. one of these modifying enzymes is xanthan lyase, which removes the terminal side chain residue of xanthan. in this paper, the cloning and sequencing of the first xanthan lyase-encoding gene is described, i. e., the xala gene, encoding pyruvated mannose-specific xanthan lyase of paenibacillus alginolyticus xl-1. the xala gene encoded a 100, 823-da protein, including a 36-amino-acid si ...	2000	10966413
phylogenetic analysis of bacterial communities in mesophilic and thermophilic bioreactors treating pharmaceutical wastewater.	the phylogenetic diversity of the bacterial communities supported by a seven-stage, full-scale biological wastewater treatment plant was studied. these reactors were operated at both mesophilic (28 to 32 degrees c) and thermophilic (50 to 58 degrees c) temperatures. community fingerprint analysis by denaturing gradient gel electrophoresis (dgge) of the pcr-amplified v3 region of the 16s rrna gene from the domain bacteria revealed that these seven reactors supported three distinct microbial commu ...	2000	10966414
exposure of phytopathogenic xanthomonas spp. to lethal concentrations of multiple oxidants affects bacterial survival in a complex manner.	during plant-microbe interactions and in the environment, xanthomonas campestris pv. phaseoli is likely to be exposed to high concentrations of multiple oxidants. here, we show that simultaneous exposures of the bacteria to multiple oxidants affects cell survival in a complex manner. a superoxide generator (menadione) enhanced the lethal effect of an organic peroxide (tert-butyl hydroperoxide) by 1, 000-fold; conversely, treatment of cells with menadione plus h(2)o(2) resulted in 100-fold protec ...	2000	10966423
effect of oxygen on formation and structure of azotobacter vinelandii alginate and its role in protecting nitrogenase.	the activity of nitrogenase in the nitrogen-fixing bacterium azotobacter vinelandii grown diazotrophically under aerobic conditions is generally considered to be protected against o(2) by a high respiration rate. in this work, we have shown that a high rate of respiration is not the prevailing mechanism for nitrogenase protection in a. vinelandii grown in phosphate-limited nitrogen-free chemostat culture. instead, the formation of alginate appeared to play a decisive role in protecting the nitro ...	2000	10966426
dna-based diagnostic approaches for identification of burkholderia cepacia complex, burkholderia vietnamiensis, burkholderia multivorans, burkholderia stabilis, and burkholderia cepacia genomovars i and iii.	bacteria of the burkholderia cepacia complex consist of five discrete genomic species, including genomovars i and iii and three new species: burkholderia multivorans (formerly genomovar ii), burkholderia stabilis (formerly genomovar iv), and burkholderia vietnamiensis (formerly genomovar v). strains of all five genomovars are capable of causing opportunistic human infection, and microbiological identification of these closely related species is difficult. the 16s rrna gene (16s rdna) and reca ge ...	2000	10970351
bacteria in the leaf ecosystem with emphasis on pseudomonas syringae-a pathogen, ice nucleus, and epiphyte.	the extremely large number of leaves produced by terrestrial and aquatic plants provide habitats for colonization by a diversity of microorganisms. this review focuses on the bacterial component of leaf microbial communities, with emphasis on pseudomonas syringae-a species that participates in leaf ecosystems as a pathogen, ice nucleus, and epiphyte. among the diversity of bacteria that colonize leaves, none has received wider attention than p. syringae, as it gained notoriety for being the firs ...	2000	10974129
from rags to riches: insights from the first genomic sequence of a plant pathogenic bacterium.	the recently published genomic sequence of xylella fastidiosa is the first for a free-living plant pathogen and provides clues to mechanisms of pathogenesis and survival in insect vectors. the sequence data should lead to improved control of this pathogen.	2000	11178244
hxc2, an arabidopsis mutant with an altered hypersensitive response to xanthomonas campestris pv. campestris.	a chemical mutagenized population of arabidopsis col-0-gl plants was screened for an altered hypersensitive response (hr) after spray inoculation with an hr-inducing isolate of xanthomonas campestris pv. campestris (strain 147). three classes of mutant were identified: those exhibiting an hr- phenotype or partial loss of hr; hyper-responsive mutants showing necrotic lesions rapidly leading to the collapse of leaves; and susceptible mutants. one mutant belonging to the susceptible class, hxc-2, w ...	2000	11135109
hrpb2 and hrpf from xanthomonas are type iii-secreted proteins and essential for pathogenicity and recognition by the host plant.	the interaction between the plant pathogen xanthomonas campestris pv. vesicatoria and its host plants is controlled by hrp genes (hypersensitive reaction and pathogenicity), which encode a type iii protein secretion system. among type iii-secreted proteins are avirulence proteins, effectors involved in the induction of plant defence reactions. using non-polar mutants, we investigated the role of 12 hrp genes in the secretion of the avirulence protein avrbs3 from x. c. pv. vesicatoria and a heter ...	2000	11115117
xylella genomics and bacterial pathogenicity to plants.	xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. inspection of the sequence reveals high relatedness to many genes of other pathogens, notably xanthomonas campestris. based on this, we suggest that xylella possesses certain easily testable properties that contribute to pathogenicity. we also present some general considerations for deriving information on pathogenicity from bacterial genomics.	2000	11119303
a two-component system involving an hd-gyp domain protein links cell-cell signalling to pathogenicity gene expression in xanthomonas campestris.	the synthesis of extracellular enzymes and extracellular polysaccharide (eps) in xanthomonas campestris pv. campestris (xcc) is regulated by a cluster of genes called rpf (for regulation of pathogenicity factors). two of the genes, rpff and rpfb, have previously been implicated in the synthesis of a diffusible regulatory molecule, dsf. here, we describe a screen of transposon insertion mutants of xcc that identified two dsf-overproducing strains. in each mutant, the gene disrupted is rpfc, which ...	2000	11123673
structure of the o-specific polysaccharides of the lipopolysaccharides of xanthomonas campestris pv. vignicola gspb 2795 and gspb 2796.	the o-specific polysaccharides of xanthomonas campestris pv. vignicola gspb 2795 and gspb 2796 were studied by sugar and methylation analyses, smith degradation, id, 2d 1h and 13c nmr spectroscopy. it was found that the polysaccharides are similar branched d-rhamnans lacking strict regularity, and their structures can be described as follows: [carbohydrate equation: see text] where rha(v) is present in a non-stoichiometric amount, which varies from strain to strain.	2000	11125825
xanthan gum: production, recovery, and properties.	xanthan gum is a microbial polysaccharide of great commercial significance. this review focuses on various aspects of xanthan production, including the producing organism xanthomonas campestris, the kinetics of growth and production, the downstream recovery of the polysaccharide, and the solution properties of xanthan.	2000	14538095
alpha-anomer-selective glucosylation of menthol with high yield through a crystal accumulation reaction using lyophilized cells of xanthomonas campestris wu-9701.	l-menthyl alpha-d-glucopyranoside (alpha-meng) is a desirable derivative of l-menthol with useful properties for the production of new flavors and novel food additives. bacteria were screened for alpha-anomer-selective glucosylation activity toward l-menthol, resulting in the isolation of two strains, xanthomonas campestris wu-9701 and stenotrophomonas maltophilia wu-9702, from independent soil samples. since the safety of x. campestris for use in the food industry is well established, wu-9701 w ...	2000	16232716
alpha-anomer-selective glucosylation of (+)-catechin by the crude enzyme, showing glucosyl transfer activity, of xanthomonas campestris wu-9701.	alpha-anomer-selective glucosylation of (+)-catechin was carried out using the crude enzyme, showing alpha-glucose transferring activity, of xanthomonas campestris wu-9701 with maltose as a glucosyl donor. when 60 mg of (+)-catechin and 50 mg of the enzyme (5.25 units as maltose hydrolysing activity) were incubated in 10 ml of 10 mm citrate-na2hpo4 buffer (ph 6.5) containing 1.2 m maltose at 45 degrees c, only one (+)-catechin glucoside was selectively obtained as a product. the (+)-catechin glu ...	2000	16232922
hbar, a 4-hydroxybenzoate sensor and fnr-crp superfamily member, regulates anaerobic 4-hydroxybenzoate degradation by rhodopseudomonas palustris.	under anaerobic conditions, structurally diverse aromatic compounds are catabolized by bacteria to form benzoyl-coenzyme a (benzoyl-coa), the starting compound for a central reductive pathway for aromatic ring degradation. the structural genes required for the conversion of 4-hydroxybenzoate (4-hba) to benzoyl-coa by rhodopseudomonas palustris have been identified. here we describe a regulatory gene, hbar, that is part of the 4-hba degradation gene cluster. an hbar mutant that was constructed wa ...	2000	10613868
role of leaf surface sugars in colonization of plants by bacterial epiphytes.	the relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of pseudomonas fluorescens on individual bean leaves. data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. sugars were depleted during the course of bacterial coloni ...	2000	10618250
mechanism of oxygen availability from hydrogen peroxide to aerobic cultures of xanthomonas campestris.	fundamental studies on the availability of oxygen from the decomposition of h(2)o(2), in vivo, by xanthomonas campestris, when h(2)o(2) is used as an oxygen source are presented. it was found that the h(2)o(2) added extracellularly (0.1-6 mm) was decomposed intracellularly. further, when h(2)o(2) was added, the flux of h(2)o(2) into the cell, is regulated by the cell. the steady-state h(2)o(2) flux into the cell was estimated to be 9.7 x 10(-8) mol m(-2) s(-1). in addition, it was proved that th ...	2000	10620764
bacterial primary colonization and early succession on surfaces in marine waters as determined by amplified rrna gene restriction analysis and sequence analysis of 16s rrna genes.	the nearly universal colonization of surfaces in marine waters by bacteria and the formation of biofilms and biofouling communities have important implications for ecological function and industrial processes. however, the dynamics of surface attachment and colonization in situ, particularly during the early stages of biofilm establishment, are not well understood. experimental surfaces that differed in their degrees of hydrophilicity or hydrophobicity were incubated in a salt marsh estuary tida ...	2000	10653705
isolation, partial sequencing, and expression of pathogenesis-related cdna genes from pepper leaves infected by xanthomonas campestris pv. vesicatoria.	specific cdnas showing differential expression in bacteria-infected pepper leaves as opposed to healthy leaves were isolated from a pepper cdna library from hypersensitive response (hr) lesions of leaves infected with an avirulent strain of xanthomonas campestris pv. vesicatoria. among a total of 282 cdna clones tested, 36 individual cdna genes (13%) hybridized strongly or differentially to the cdna probes from bacteria-infected leaves. ten capsicum annuum-induced (cai) genes encoding putative t ...	2000	10656596
cdna-aflp analysis of differential gene expression in the prokaryotic plant pathogen erwinia carotovora.	for studies of differential gene expression in prokaryotes, methods for synthesizing representative cdna populations are required. here, a technique is described for the synthesis of cdna from the potato pathogens erwinia carotovora subsp. atroseptica (eca) and erwinia carotovora subsp. carotovora (ecc) using a combination of short oligonucleotide (11-mer) primers that were known to anneal to conserved sequences in the 3' regions of enterobacterial genes. specific pcr amplifications with primers ...	2000	10658663
effects of calcium and calcium chelators on growth and morphology of escherichia coli l-form nc-7.	growth of a wall-less, l-form of escherichia coli specifically requires calcium, and in its absence, cells ceased dividing, became spherical, swelled, developed large vacuoles, and eventually lysed. the key cell division protein, ftsz, was present in the l-form at a concentration five times less than that in the parental strain. one interpretation of these results is that the l-form possesses an enzoskeleton partly regulated by calcium.	2000	10671467
expression analysis and characterization of the mutant of a growth-phase- and starvation-regulated monofunctional catalase gene from xanthomonas campestris pv. phaseoli.	analysis of the xanthomonas campestris pv. phaseoli (xp) catalase profile using an activity gel revealed at least two distinct monofunctional catalase isozymes denoted kat1 and kat2. kat1 was expressed throughout growth, whereas kat2 was expressed only during the stationary phase of growth. the nucleotide sequence of a previously isolated monofunctional catalase gene, xp kate, was determined. the deduced amino acid sequence of xp kate showed a high percentage identity to an atypical group of mon ...	2000	10675038
nitric oxide modulates the activity of tobacco aconitase.	recent evidence suggests an important role for nitric oxide (no) signaling in plant-pathogen interactions. additional elucidation of the role of no in plants will require identification of no targets. since aconitases are major no targets in animals, we examined the effect of no on tobacco (nicotiana tabacum) aconitase. the tobacco aconitases, like their animal counterparts, were inhibited by no donors. the cytosolic aconitase in animals, in addition to being a key redox and no sensor, is conver ...	2000	10677450
actinobacillus pleuropneumoniae iron transport: a set of exbbd genes is transcriptionally linked to the tbpb gene and required for utilization of transferrin-bound iron.	upon iron restriction, actinobacillus pleuropneumoniae has been shown to express the transferrin-binding proteins tbpb and tbpa, both of which have been implied to be important virulence factors. in order to identify additional iron-regulated proteins, we cloned and analyzed the region upstream of the transferrin-binding protein genes in an a. pleuropneumoniae serotype 7 strain. we located immediately upstream of the tbpb gene two open reading frames which were 43% homologous to the neisserial e ...	2000	10678921
identification of a lexa gene in, and construction of a lexa mutant of, xanthomonas campestris pv. citri.	the lexa gene of xanthomonas campestris pathovar citri (x.c. pv. citri) was cloned and sequenced. the 639-bp open reading frame encodes a protein of 213 amino acids that shares substantial sequence homology with the products of previously characterized lexa genes, sharing 46% identity with the lexa protein of escherichia coli. amino acids required for autocatalytic cleavage of lexa are conserved in the x.c. pv. citri protein, whereas domains thought to mediate dna binding differ markedly from th ...	2000	10688691
association of the cytoplasmic membrane protein xpsn with the outer membrane protein xpsd in the type ii protein secretion apparatus of xanthomonas campestris pv. campestris.	an xps gene cluster composed of 11 open reading frames is required for the type ii protein secretion in xanthomonas campestris pv. campestris. immediately upstream of the xpsd gene, which encodes an outer membrane protein that serves as the secretion channel by forming multimers, there exists an open reading frame (previously designated orf2) that could encode a protein of 261 amino acid residues. its n-terminal hydrophobic region is a likely membrane-anchoring sequence. antibody raised against ...	2000	10692359
succession of microbial communities during hot composting as detected by pcr-single-strand-conformation polymorphism-based genetic profiles of small-subunit rrna genes.	a cultivation-independent technique for genetic profiling of pcr-amplified small-subunit rrna genes (ssu rdna) was chosen to characterize the diversity and succession of microbial communities during composting of an organic agricultural substrate. pcr amplifications were performed with dna directly extracted from compost samples and with primers targeting either (i) the v4-v5 region of eubacterial 16s rrna genes, (ii) the v3 region in the 16s rrna genes of actinomycetes, or (iii) the v8-v9 regio ...	2000	10698754
survival and epiphytic fitness of a nonpathogenic mutant of xanthomonas campestris pv. glycines.	xanthomonas campestris pv. glycines is the causal agent of bacterial pustule disease of soybeans. the objective of this work was to construct a nonpathogenic mutant derived from the pathogenic wild-type strain yr32 and to evaluate its effectiveness in preventing growth of its parent on the soybean phyllosphere. a mini-tn5-derived transposon was used to generate nonpathogenic mutants. southern hybridization and pulsed-field gel electrophoresis confirmed the presence of a single transposon in each ...	2000	10698789
microbial relatives of the seed storage proteins of higher plants: conservation of structure and diversification of function during evolution of the cupin superfamily.	this review summarizes the recent discovery of the cupin superfamily (from the latin term "cupa," a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic beta-barrel core, led to the identification of a small number of conserved residues a ...	2000	10704478
salicylic acid mediated by the oxidative burst is a key molecule in local and systemic responses of cotton challenged by an avirulent race of xanthomonas campestris pv malvacearum.	we analyzed the production of reactive oxygen species, the accumulation of salicylic acid (sa), and peroxidase activity during the incompatible interaction between cotyledons of the cotton (gossypium hirsutum) cv reba b50/xanthomonas campestris pv malvacearum (xcm) race 18. sa was detected in petioles of cotyledons 6 h after infection and 24 h post inoculation in cotyledons and untreated leaves. the first peak of sa occurred 3 h after generation of superoxide (o(2)(.-)), and was inhibited by inf ...	2000	10712539
identification of two novel hrp-associated genes in the hrp gene cluster of xanthomonas oryzae pv. oryzae.	we have cloned a hrp gene cluster from xanthomonas oryzae pv. oryzae. bacteria with mutations in the hrp region have reduced growth in rice leaves and lose the ability to elicit a hypersensitive response (hr) on the appropriate resistant cultivars of rice and the nonhost plant tomato. a 12,165-bp portion of nucleotide sequence from the presumed left end and extending through the hrpb operon was determined. the region was most similar to hrp genes from xanthomonas campestris pv. vesicatoria and r ...	2000	10714988
secreted enzymatic activities of wild-type and pild-deficient legionella pneumophila.	legionella pneumophila, the agent of legionnaires' disease, is an intracellular pathogen of protozoa and macrophages. previously, we had determined that the legionella pild gene is involved in type iv pilus biogenesis, type ii protein secretion, intracellular infection, and virulence. since the loss of pili and a protease do not account for the infection defect exhibited by a pild-deficient strain, we sought to define other secreted proteins absent in the mutant. based upon the release of p-nitr ...	2000	10722574
bordetella pertussis tonb, a bvg-independent virulence determinant.	in gram-negative bacteria, high-affinity iron uptake requires the tonb/exbb/exbd envelope complex to release iron chelates from their specific outer membrane receptors into the periplasm. based on sequence similarities, the bordetella pertussis tonb exbb exbd locus was identified on a cloned dna fragment. the tight organization of the three genes suggests that they are cotranscribed. a putative fur-binding sequence located upstream from tonb was detected in a fur titration assay, indicating that ...	2000	10722583
type iv pilus genes pila and pilc of pseudomonas stutzeri are required for natural genetic transformation, and pila can be replaced by corresponding genes from nontransformable species.	pseudomonas stutzeri lives in terrestrial and aquatic habitats and is capable of natural genetic transformation. after transposon mutagenesis, transformation-deficient mutants were isolated from a p. stutzeri jm300 strain. in one of them a gene which coded for a protein with 75% amino acid sequence identity to pilc of pseudomonas aeruginosa, an accessory protein for type iv pilus biogenesis, was inactivated. the presence of type iv pili was demonstrated by susceptibility to the type iv pilus-dep ...	2000	10735861
functional analysis of gapped microbial genomes: amino acid metabolism of thiobacillus ferrooxidans.	a gapped genome sequence of the biomining bacterium thiobacillus ferrooxidans strain atcc23270 was assembled from sheared dna fragments (3.2-times coverage) into 1,912 contigs. a total of 2,712 potential genes (orfs) were identified in 2.6 mbp (megabase pairs) of thiobacillus genomic sequence. of these genes, 2,159 could be assigned functions by using the wit-pro/emp genome analysis system, most with a high degree of certainty. nine hundred of the genes have been assigned roles in metabolic path ...	2000	10737802
superoxide dismutase activity in pseudomonas putida affects utilization of sugars and growth on root surfaces.	to investigate the role of superoxide dismutases (sod) in root colonization and oxidative stress, mutants of pseudomonas putida lacking manganese-superoxide dismutase (mnsod) (soda), iron-superoxide dismutase (fesod) (sodb), or both were generated. the soda sodb mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. the sodb and soda sodb mutants were more sensitive than wild type to oxidative stress generated within the cell by paraquat treatment. in sing ...	2000	10742227
mutants of xanthomonas oryzae pv. oryzae deficient in general secretory pathway are virulence deficient and unable to secrete xylanase.	xanthomonas oryzae pv. oryzae (xoo) causes bacterial leaf blight, a serious disease of rice. a virulence- and xylanase-deficient mutant of xoo was isolated following ethyl methane sulfonate (ems) mutagenesis. a cosmid clone that restored virulence and xylanase secretion was obtained from a genomic library by functional complementation. transposon mutagenesis and marker exchange studies revealed genes on the cloned dna that were required for xylanase production and virulence. sequence analysis wi ...	2000	10755302
genotypic characterization of xanthomonad strains isolated from passion fruit plants (passiflora spp.) and their relatedness to different xanthomonas species.	the genetic diversity of 55 xanthomonad strains isolated from passion fruit plants (passiflora spp.) and identified as xanthomonas campestris pv. passiflorae was initially assessed by randomly amplified polymorphic dna (rapd) analysis. the strains showed a high level of polymorphism with almost unique fingerprints. fifteen clusters with a similarity of approximately 70% were identified, three of which were prevalent. there was a correlation between the clusters and the geographic origin of the s ...	2000	10758892
[rapd-markers linked to the locus for resistance to the race 4 pathogen for black rot, xanthomonas campestris pv. campestris (pamm.) dow., in brassica rapa l].	association between the rapd markers and the resistance to race 4 of the black rot causative agent was studied in brassica rapa l. experiments were carried out using doubled haploid lines, obtained via crosses between the race 4-susceptible fodder turnip and resistant pak-choi, and the f2 progeny of the crosses between the doubled haploid lines with contrasting resistance. the we(22)980 rapd marker inherited from the pak-choi and associated with the clubroot susceptibility was also linked to the ...	2000	10779910
the pseudomonas syringae hrp pathogenicity island has a tripartite mosaic structure composed of a cluster of type iii secretion genes bounded by exchangeable effector and conserved effector loci that contribute to parasitic fitness and pathogenicity in plants.	the plant pathogenic bacterium pseudomonas syringae is divided into pathovars differing in host specificity, with p. syringae pv. syringae (psy) and p. syringae pv. tomato (pto) representing particularly divergent pathovars. p. syringae hrp/hrc genes encode a type iii protein secretion system that appears to translocate avr and hop effector proteins into plant cells. dna sequence analysis of the hrp/hrc regions in psy 61, psy b728a, and pto dc3000 has revealed a hrp pathogenicity island (pai) wi ...	2000	10781092
prephenate dehydratase from the aphid endosymbiont (buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibition by phenylalanine.	buchnera aphidicola, the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. we have cloned and sequenced a region of the genome of b. aphidicola isolated from acyrthosiphon pisum which includes the two-domain aroq/phea gene. this gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l-phenylalanine biosynthesis. two changes involved in the overproduction of ...	2000	10781569
structure of the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. manihotis gspb 2755 and gspb 2364.	the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. manihotis strains gspb 2755 and gspb 2364 was studied by sugar and methylation analyses and 1h and 13c nmr spectroscopy, including 2d cosy, tocsy, noesy, and h-detected 1h, 13c heteronuclear multiple-quantum coherence (hmqc) experiments. the polysaccharide was found to contain l-rhamnose and l-xylose in the ratio 3:1, and the following structure of the tetrasaccharide repeating unit was established: [formula: see ...	2000	10782308
novel genes involved in the regulation of pathogenicity factor production within the rpf gene cluster of xanthomonas campestris.	the synthesis of extracellular enzymes and extracellular polysaccharide (eps) in xanthomonas campestris pathovar campestris (xcc) is subject to co-ordinate regulation by a cluster of genes called rpf (for regulation of pathogenicity factors). these genes are located within a 21.9 kb region of the chromosome isolated as the cosmid clone pij3020. the genes in the left-hand section of this region of the chromosome have previously been characterized. this paper reports on the genes in the right-hand ...	2000	10784047
design and evaluation of a lactobacillus manihotivorans species-specific rrna-targeted hybridization probe and its application to the study of sour cassava fermentation.	based on 16s rrna sequence comparison, we have designed a 20-mer oligonucleotide that targets a region specific to the species lactobacillus manihotivorans recently isolated from sour cassava fermentation. the probe recognized the rrna obtained from all the l. manihotivorans strains tested but did not recognize 56 strains of microorganisms from culture collections or directly isolated from sour cassava, including 29 species of lactic acid bacteria. this probe was then successfully used in quanti ...	2000	10788405
identification of the pgmg gene, encoding a bifunctional protein with phosphoglucomutase and phosphomannomutase activities, in the gellan gum-producing strain sphingomonas paucimobilis atcc 31461.	the pgmg gene of sphingomonas paucimobilis atcc 31461, the industrial gellan gum-producing strain, was cloned and sequenced. it encodes a 50,059-da polypeptide that has phosphoglucomutase (pgm) and phosphomannomutase (pmm) activities and is 37 to 59% identical to other bifunctional proteins with pgm and pmm activities from gram-negative species, including pseudomonas aeruginosa algc. purified pgmg protein showed a marked preference for glucose-1-phosphate (g1p); the catalytic efficiency was abou ...	2000	10788412
the tomato ethylene receptors nr and leetr4 are negative regulators of ethylene response and exhibit functional compensation within a multigene family.	the plant hormone ethylene is involved in many developmental processes, including fruit ripening, abscission, senescence, and leaf epinasty. tomato contains a family of ethylene receptors, designated leetr1, leetr2, nr, leetr4, and leetr5, with homology to the arabidopsis etr1 ethylene receptor. transgenic plants with reduced leetr4 gene expression display multiple symptoms of extreme ethylene sensitivity, including severe epinasty, enhanced flower senescence, and accelerated fruit ripening. the ...	2000	10792050
genetic polymorphism in xanthomonas albilineans strains originating from 11 geographical locations, revealed by two dna probes.	two dna fragments from xanthomonas albilineans were used as probes to study the molecular diversity among strains of this pathogen. two serologically distinct groups, serovars i and ii, could be differentiated by hybridization to the probes. these probes, designated 830 and 838, were cloned after subtractive dna hybridization of common sequences of xanthomonas campestris pv. vasculorum from a serovar i strain of x. albilineans. they did not hybridize to the dna of several other xanthomonads or t ...	2000	10792648
structure elucidation of the o-chain from the major lipopolysaccharide of the xanthomonas campestris strain 642.	a novel o-polysaccharide consisting of d-xylp and l-rhap in the molar ratio of 1:2.5 was identified as the major component in the lipopolysaccharide fraction of xanthomonas campestris strain 642, which is responsible for a new bacterial disease of the strawberry plant. its structure was mainly determined using chemical analysis, smith degradation and 1d and 2d nmr spectroscopy experiments as: carbohydrate sequence [see text].	2000	10795814
response to xanthomonas campestris pv. vesicatoria in tomato involves regulation of ethylene receptor gene expression.	although ethylene regulates a wide range of defense-related genes, its role in plant defense varies greatly among different plant-microbe interactions. we compared ethylene's role in plant response to virulent and avirulent strains of xanthomonas campestris pv. vesicatoria in tomato (lycopersicon esculentum mill.). the ethylene-insensitive never ripe (nr) mutant displays increased tolerance to the virulent strain, while maintaining resistance to the avirulent strain. expression of the ethylene r ...	2000	10806227
cloning and expression of ntnd, encoding a novel nad(p)(+)-independent 4-nitrobenzyl alcohol dehydrogenase from pseudomonas sp. strain tw3.	pseudomonas sp. strain tw3 is able to metabolize 4-nitrotoluene to 4-nitrobenzoate and toluene to benzoate aerobically via a route analogous to the upper pathway of the tol plasmids. we report the cloning and characterization of a benzyl alcohol dehydrogenase gene (ntnd) which encodes the enzyme for the catabolism of 4-nitrobenzyl alcohol and benzyl alcohol to 4-nitrobenzaldehyde and benzaldehyde, respectively. the gene is located downstream of the previously reported ntn gene cluster. ntnd bear ...	2000	10809692
prey range characterization, ribotyping, and diversity of soil and rhizosphere bdellovibrio spp. isolated on phytopathogenic bacteria.	thirty new bdellovibrio strains were isolated from an agricultural soil and from the rhizosphere of plants grown in that soil. using a combined molecular and culture-based approach, we found that the soil bdellovibrios included subpopulations of organisms that differed from rhizosphere bdellovibrios. thirteen soil and seven common bean rhizosphere bdellovibrio strains were isolated when pseudomonas corrugata was used as prey; seven and two soil strains were isolated when erwinia carotovora subsp ...	2000	10831412
the exbd2 gene as well as the iron-uptake genes tonb, exbb and exbd1 of xanthomonas campestris pv. campestris are essential for the induction of a hypersensitive response on pepper (capsicum annuum).	the tonb, exbb and exbd1 genes of xanthomonas campestris pv. campestris are essential for ferric iron uptake. in contrast, the exbd2 gene located in the same gene cluster is not essential. mutational analysis revealed that the ferric-iron-uptake genes tonb, exbb and exbd1 are necessary for the induction of a hypersensitive response (hr) on the nonhost plant pepper (capsicum annuum) and the induction of typical black rot symptoms on the host plant cauliflower (brassica oleracea). again, the exbd2 ...	2000	10832632
identification of sinorhizobium meliloti genes regulated during symbiosis.	rna fingerprinting by arbitrarily primed pcr was used to isolate sinorhizobium meliloti genes regulated during the symbiotic interaction with alfalfa (medicago sativa). sixteen partial cdnas were isolated whose corresponding genes were differentially expressed between symbiotic and free-living conditions. thirteen sequences corresponded to genes up-regulated during symbiosis, whereas three were instead repressed during establishment of the symbiotic interaction. seven cdnas corresponded to known ...	2000	10850975
role of the dpr product in oxygen tolerance in streptococcus mutans.	we have previously identified and characterized the alkyl hydroperoxide reductase of streptococcus mutans, which consists of two components, nox-1 and ahpc. deletion of both nox-1 and ahpc had no effect on the sensitivity of s. mutans to cumene hydroperoxide or h(2)o(2), implying that the existence of another antioxidant system(s) independent of the nox-1-ahpc system compensates for the deficiency. here, a new antioxidant gene (dpr for dps-like peroxide resistance gene) was isolated from the s. ...	2000	10850989
marinomonas mediterranea mmb-1 transposon mutagenesis: isolation of a multipotent polyphenol oxidase mutant.	marinomonas mediterranea is a melanogenic marine bacterium expressing a multifunctional polyphenol oxidase (ppo) able to oxidize substrates characteristic for laccases and tyrosinases, as well as produce a classical tyrosinase. a new and quick method has been developed for screening laccase activity in culture plates to detect mutants differentially affected in this ppo activity. transposon mutagenesis has been applied for the first time to m. mediterranea by using different minitransposons load ...	2000	10850991
mutations in oxyr resulting in peroxide resistance in xanthomonas campestris.	a spontaneous xanthomonas campestris pv. phaseoli h(2)o(2)-resistant mutant emerged upon selection with 1 mm h(2)o(2). in this report, we show that growth of this mutant under noninducing conditions gave high levels of catalase, alkyl hydroperoxide reductase (ahpc and ahpf), and oxyr. the h(2)o(2) resistance phenotype was abolished in oxyr-minus derivatives of the mutant, suggesting that elevated levels and mutations in oxyr were responsible for the phenotype. nucleotide sequence analysis of the ...	2000	10851004
virulence of the phytopathogen pseudomonas syringae pv. maculicola is rpon dependent.	we cloned the rpon (ntra and glnf) gene encoding sigma(54) from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. the p. syringae es4326 rpon gene complemented pseudomonas aeruginosa, escherichia coli, and klebsiella aerogenes rpon mutants for a variety of rpon mutant phenotypes, including the inability to utilize nitrate as sole nitrogen source. dna sequence analysis of the p. syringae es4326 rpon gene revealed that the deduced amino acid sequence was most similar (86% identi ...	2000	10852883
the alternative sigma factor rpon is required for hrp activity in pseudomonas syringae pv. maculicola and acts at the level of hrpl transcription.	beta-glucuronidase (uida) reporter gene fusions were constructed for the hrpz, hrpl, and hrps genes from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. these reporters, as well as an avrrpt2-uida fusion, were used to measure transcriptional activity in es4326 and a es4326 rpon mutant. rpon was required for the expression of avrrpt2, hrpz, and hrpl in vitro in minimal media and in vivo when infiltrated into arabidopsis thaliana leaves. in contrast, the expression of hrps was ...	2000	10852884
importance of holotoxin assembly in ptl-mediated secretion of pertussis toxin from bordetella pertussis.	we examined the structural components of pertussis toxin that are required for efficient export from bordetella pertussis via the ptl system, a member of the type iv family of macromolecular transporters. first, we constructed a strain of b. pertussis that contains a functional ptl system but does not produce pertussis toxin. plasmids which express either the s1 subunit or the b oligomer were then introduced into this strain. we found that the b oligomer of the toxin is not secreted in the absen ...	2000	10858221
influence of deletions within domain ii of exotoxin a on its extracellular secretion from pseudomonas aeruginosa.	pseudomonas aeruginosa is a gram-negative bacterium that secretes many proteins into the extracellular medium via the xcp machinery. this pathway, conserved in gram-negative bacteria, is called the type ii pathway. the exoproteins contain information in their amino acid sequence to allow targeting to their secretion machinery. this information may be present within a conformational motif. the nature of this signal has been examined for p. aeruginosa exotoxin a (pe). previous studies failed to id ...	2000	10869085
bioaugmentation of activated sludge by an indigenous 3-chloroaniline-degrading comamonas testosteroni strain, i2gfp.	a strain identified as comamonas testosteroni i2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-ca). during the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. this strain was tested for its ability to clean wastewater containing 3-ca upon inoculation into activated sludge. to monitor its survival, the strain was chromosomally marked with the gfp gene and designated i2gfp. after inoculatio ...	2000	10877785
molecular analysis of surfactant-driven microbial population shifts in hydrocarbon-contaminated soil.	we analyzed the impact of surfactant addition on hydrocarbon mineralization kinetics and the associated population shifts of hydrocarbon-degrading microorganisms in soil. a mixture of radiolabeled hexadecane and phenanthrene was added to batch soil vessels. witconol sn70 (a nonionic, alcohol ethoxylate) was added in concentrations that bracketed the critical micelle concentration (cmc) in soil (cmc') (determined to be 13 mg g(-1)). addition of the surfactant at a concentration below the cmc' (2 ...	2000	10877792
variation among strains of xanthomonas campestris pv. vasculorum from mauritius and other countries based on fatty acid analysis.	fatty acid profiling was used to study variation amongst strains of xanthomonas campestris pv. vasculorum (xcv). they could be divided into five groups using cellular fatty acid profiles. group a strains represent a new and little known taxon and all came from plants of broom bamboo (thysanolaena maxima) from mauritius. group b strains included the xcv pathotype reference strain and were from palms, broom bamboo and sugarcane from mauritius, reunion and australia. group c contained southern afri ...	2000	10879989
cultivar-specific avirulence and virulence functions assigned to avrpphf in pseudomonas syringae pv. phaseolicola, the cause of bean halo-blight disease.	the avrpphf gene was cloned from pseudomonas syringae pathovar phaseolicola (pph:) races 5 and 7, based on its ability to confer avirulence towards bean cultivars carrying the r1 gene for halo-blight resistance, such as red mexican. avrpphf comprised two open reading frames, which were both required for function, and was located on a 154 kb plasmid (pav511) in pph: strain rw60 of pph:, lacking pav511, displayed a loss in virulence to a range of previously susceptible cultivars such as tendergree ...	2000	10880434
[major-polygene effect analysis of resistance to bacterial blight (xanthomonas campestris pv. oryzae) in rice].	five crosses between resistance and susceptible were analyzed to study major-polygene effect using major-polygene mixed mode. the result showed that 3 of 5 crosses were controlled by both major gene and polygene. in addition, there were large variation of additive effect, variance as well as heredity of major gene polygene in 3 crosses. major gene was predominant in resistant variation, but durability should be considered. we suggested that construct major-polygene system be constructed in the l ...	2000	10883537
enhancement of induced disease resistance by simultaneous activation of salicylate- and jasmonate-dependent defense pathways in arabidopsis thaliana.	the plant-signaling molecules salicylic acid (sa) and jasmonic acid (ja) play an important role in induced disease resistance pathways. cross-talk between sa- and ja-dependent pathways can result in inhibition of ja-mediated defense responses. we investigated possible antagonistic interactions between the sa-dependent systemic acquired resistance (sar) pathway, which is induced upon pathogen infection, and the ja-dependent induced systemic resistance (isr) pathway, which is triggered by nonpatho ...	2000	10890883
sequence and molecular analysis of the rpoa cluster genes from xanthomonas campestris pv. campestris.	the xanthomonas campestris rpsm (s13)-rpsk (s11)-rpsd (s4)-rpoa (alpha)-rplq (l17) cluster, encoding rna polymerase alpha-subunit and four ribosomal proteins, reside in a 3164-bp dna region. the n-terminal sequence of the authentic alpha-protein determined chemically matches that predicted from the nucleotide sequence. rplq is monocistronic, instead of being co-transcribed with the other genes as in escherichia coli. antiserum against the his-tagged alpha-protein cross-reacted with the e. coli a ...	2000	10899600
requirement of the pseudomonas aeruginosa tonb gene for high-affinity iron acquisition and infection.	to investigate the contribution of the tonb protein to high-affinity iron acquisition in pseudomonas aeruginosa, we constructed tonb-inactivated mutants from strain pao1 and its derivative deficient in producing the siderophores pyoverdin and pyochelin. the tonb mutants could not grow in a free-iron-restricted medium prepared by apotransferrin addition, even though the medium was supplemented with each purified siderophore or with a heme source (hemoglobin or hemin). the tonb inactivation was sh ...	2000	10899848
role of phosphoglucomutase of bordetella bronchiseptica in lipopolysaccharide biosynthesis and virulence.	the phosphoglucomutase (pgm)-encoding gene of bordetella bronchiseptica is required for lipopolysaccharide (lps) biosynthesis. an insertion mutant of the wild-type b. bronchiseptica strain bb7865 which disrupted lps biosynthesis was created and characterized (bb7865pgm). genetic analysis of the mutated gene showed it shares high identity with pgm genes of various bacterial species and forms part of an operon which also encompasses the gene encoding phosphoglucose isomerase. functional assays for ...	2000	10899872
a protease-resistant catalase, kata, released upon cell lysis during stationary phase is essential for aerobic survival of a pseudomonas aeruginosa oxyr mutant at low cell densities.	a pseudomonas aeruginosa oxyr mutant was dramatically sensitive to h(2)o(2), despite possessing wild-type catalase activity. oxygen-dependent oxyr phenotypes also included an inability to survive aerobic serial dilution in luria broth and to resist aminoglycosides. plating the oxyr mutant after serial dilution in its own spent culture supernatant, which contained the major catalase kata, or under anaerobic conditions allowed for survival. kata was resistant to sodium dodecyl sulfate, proteinase ...	2000	10913089
novel insertion sequence elements associated with genetic heterogeneity and phenotype conversion in ralstonia solanacearum.	three insertion sequences (is) elements were isolated from the phytopathogen ralstonia solanacearum. southern hybridization using these is elements as probes revealed hybridization profiles that varied greatly between different strains of the pathogen. during a spontaneous phenotype conversion event, the promoter of the phca gene was interrupted by one of these is elements.	2000	10913109
effect of field inoculation with sinorhizobium meliloti l33 on the composition of bacterial communities in rhizospheres of a target plant (medicago sativa) and a non-target plant (chenopodium album)-linking of 16s rrna gene-based single-strand conformation polymorphism community profiles to the diversity of cultivated bacteria.	fourteen weeks after field release of luciferase gene-tagged sinorhizobium meliloti l33 in field plots seeded with medicago sativa, we found that the inoculant also occurred in bulk soil from noninoculated control plots. in rhizospheres of m. sativa plants, s. meliloti l33 could be detected in noninoculated plots 12 weeks after inoculation, indicating that growth in the rhizosphere preceded spread into bulk soil. to determine whether inoculation affected bacterial diversity, 1,119 bacteria were ...	2000	10919821
pseudomonas syringae hrp type iii secretion system and effector proteins.	pseudomonas syringae is a member of an important group of gram-negative bacterial pathogens of plants and animals that depend on a type iii secretion system to inject virulence effector proteins into host cells. in p. syringae, hrp/hrc genes encode the hrp (type iii secretion) system, and avirulence (avr) and hrp-dependent outer protein (hop) genes encode effector proteins. the hrp/hrc genes of p. syringae pv syringae 61, p. syringae pv syringae b728a, and p. syringae pv tomato dc3000 are flanke ...	2000	10922033
molecular and cell biology aspects of plague.	a 70-kb virulence plasmid (sometimes called pyv) enables yersinia spp. to survive and multiply in the lymphoid tissues of their host. it encodes the yop virulon, a system consisting of secreted proteins called yops and their dedicated type iii secretion apparatus called ysc. the ysc apparatus forms a channel composed of 29 proteins. of these, 10 have counterparts in almost every type iii system. secretion of some yops requires the assistance, in the bacterial cytosol, of small individual chapero ...	2000	10922034
parameters affecting gene expression from the pm promoter in gram-negative bacteria.	the pm promoter inserted chromosomally or in broad-host-range replicons based on plasmid rsf1010 or rk2 are useful systems for both high- and low-level expression of cloned genes in several gram-negative bacterial species. the positive pm regulator xyls is activated by certain substituted benzoic acid derivatives, and here we show that these effectors induce expression of pm at similar relative ranking levels in both escherichia coli and pseudomonas aeruginosa however, the kinetics of expression ...	2000	10935724