| characterization of a tonb mutation in erwinia chrysanthemi 3937: tonb(ech) is a member of the enterobacterial tonb family. | the pectinolytic enterobacterium erwinia chrysanthemi 3937 causes a systemic disease in its natural host, the african violet (saintpaulia: ionantha). it produces two structurally unrelated siderophores, chrysobactin and achromobactin. chrysobactin makes a large contribution to invasive growth of the bacterium in its host. insertion mutants of a chrysobactin-defective strain were constructed and screened on the universal cas-agar medium used for siderophore detection. a set of mutants affected in ... | 2000 | 10931909 |
| phenotypic and genotypic characterization of antagonistic bacteria associated with roots of transgenic and non-transgenic potato plants. | rhizobacteria obtained during a risk assessment study from parental and transgenic t4 lysozyme-expressing potato plants were investigated to determine whether or not the strains could be grouped based on the source of isolation, transgenic or non-transgenic plants, respectively. a total of 68 representative bacterial strains of the group of enterics and pseudomonads were investigated by phenotypic profiling (the antagonistic activity towards bacterial and fungal plant pathogens, the production o ... | 2001 | 11372657 |
| external ph: an environmental signal that helps to rationalize pel gene duplication in erwinia chrysanthemi. | the phytopathogenic bacterium erwinia chrysanthemi produces five major pectate lyases that are key virulence factors in soft-rot disease development. using transcriptional fusions, we studied the regulation of pela, peld, and pele gene expression as a function of variation of the external ph. pela and peld were expressed when bacteria were grown in an acidic medium while pele was transcribed only in basic medium. using phenol red, we observed that, in chicory leaves, ph value of infected tissue ... | 2000 | 10939260 |
| essential role of superoxide dismutase on the pathogenicity of erwinia chrysanthemi strain 3937. | the soda gene from erwinia chrysanthemi strain 3937 was cloned by functional complementation of an escherichia coli soda sodb mutant and sequenced. we identified a 639-bp open reading frame, which encodes a protein that is 85% identical to the e. coli manganese-containing superoxide dismutase mnsod. promoter elements of this gene were identified by transcriptional mapping experiments. we constructed an e. chrysanthemi deltasoda mutant by reverse genetics. the deltasoda mutation resulted in the a ... | 2001 | 11386371 |
| synergistic hydrolysis of carboxymethyl cellulose and acid-swollen cellulose by two endoglucanases (celz and cely) from erwinia chrysanthemi. | erwinia chrysanthemi produces a battery of hydrolases and lyases which are very effective in the maceration of plant cell walls. although two endoglucanases (celz and cely; formerly egz and egy) are produced, celz represents approximately 95% of the total carboxymethyl cellulase activity. in this study, we have examined the effectiveness of cely and celz alone and of combinations of both enzymes using carboxymethyl cellulose (cmc) and amorphous cellulose (acid-swollen cellulose) as substrates. s ... | 2000 | 11004164 |
| functional implications of the beta-helical protein fold: differences in chemical and thermal stabilities of erwinia chrysanthemi ec16 pectate lyases b, c, and e. | colonization of plant tissue by the phytopathogen erwinia chrysanthemi ec16 is aided by the activities of the pectate lyase isozymes (pls), which depolymerize the polygalacturonic acid component (pga) of plant cell walls. the bacterium secretes four pectate lyases (pla, plb, plc, and ple), two of which, plc and ple, have been shown to fold into a similar domain motif, the beta-helix. to understand the rationale behind the evolution and retention of these isoforms, the susceptibilities of pectate ... | 2000 | 11032414 |
| a potato gene encoding a wrky-like transcription factor is induced in interactions with erwinia carotovora subsp. atroseptica and phytophthora infestans and is coregulated with class i endochitinase expression. | a potato gene encoding a putative wrky protein was isolated from a cdna library enriched by suppression subtractive hybridization for sequences upregulated 1 h postinoculation with erwinia carotovora subsp. atroseptica. the cdna encodes a putative polypeptide of 172 amino acids, containing a single wrky domain with a zinc finger motif and preceded by a potential nuclear localization site. st-wrky1 was strongly upregulated in compatible, but only weakly in incompatible, interactions with phytopht ... | 2000 | 11043470 |
| resolution of four pectate lyase structural genes of erwinia chrysanthemi (ec16) and characterization of the enzymes produced in escherichia coli. | | 1987 | 11394411 |
| subset of hybrid eukaryotic proteins is exported by the type i secretion system of erwinia chrysanthemi. | erwinia chrysanthemi exports degradative enzymes by using a type i protein secretion system. the proteases secreted by this system lack an n-terminal signal peptide but contain a c-terminal secretion signal. to explore the substrate specificity of this system, we have expressed the e. chrysanthemi transporter system (prtdef genes) in escherichia coli and tested the ability of this abc transporter to export hybrid proteins carrying c-terminal fragments of e. chrysanthemi protease b. the c terminu ... | 2001 | 11157948 |
| three-dimensional structure of erwinia chrysanthemi pectin methylesterase reveals a novel esterase active site. | most structures of neutral lipases and esterases have been found to adopt the common alpha/beta hydrolase fold and contain a catalytic ser-his-asp triad. some variation occurs in both the overall protein fold and in the location of the catalytic triad, and in some enzymes the role of the aspartate residue is replaced by a main-chain carbonyl oxygen atom. here, we report the crystal structure of pectin methylesterase that has neither the common alpha/beta hydrolase fold nor the common catalytic t ... | 2001 | 11162105 |
| role of the nucleoid-associated protein h-ns in the synthesis of virulence factors in the phytopathogenic bacterium erwinia chrysanthemi. | the ability of the enterobacterium erwinia chrysanthemi to induce pathogenesis in plant tissue is strongly related to the massive production of plant-cell-wall-degrading enzymes (pectinases, cellulases, and proteases). additional factors, including flagellar proteins and exopolysaccharides (eps), also are required for the efficient colonization of plants. production of these virulence factors, particularly pectate lyases, the main virulence determinant, is tightly regulated by environmental cond ... | 2001 | 11194867 |
| nkbor, a mini-tn10-based transposon for random insertion in the chromosome of gram-negative bacteria and the rapid recovery of sequences flanking the insertion sites in escherichia coli. | we have constructed an r6k-based suicide vector that permits the random insertion of a mini-transposon named nkbor into the chromosome of gram-negative bacteria and the subsequent rapid cloning of sequences flanking the insertion site in escherichia coli. this mini-transposon contains a conditional r6k plasmid origin of replication, a kanamycin resistance gene and unique restriction sites between the is10 inverted repeats. nkbor can be propagated by replication in an e. coli strain containing th ... | 2001 | 11446516 |
| extracellular polysaccharides of modified strains of erwinia spp. | the structure of the extracellular polysaccharide (eps) produced by erwinia chrysanthemi strain a2148 has been determined using low pressure size-exclusion and anion-exchange chromatographies, high ph anion-exchange chromatography, glycosyl-linkage analysis, and 1d 1h nmr spectroscopy. the polysaccharide is structurally similar, if not identical, to the eps produced by e. chrysanthemi strain a350. a streptomycin-resistant strain of e. chrysanthemi ech6 (ech6s(+)) has been generated and has an el ... | 2001 | 11454336 |
| silencing the majority. | | 2001 | 11479563 |
| the hexy genes of erwinia carotovora ssp. carotovora and ssp. atroseptica encode novel proteins that regulate virulence and motility co-ordinately. | mutations located in a new gene, hexy, in erwinia carotovora ssp. carotovora (ecc) and ssp. atroseptica (eca) cause strong upregulation of production of exoenzyme virulence factors and motility. the hexy gene encodes a novel 14.4 kda protein with no known homologues. the hexy mrna transcript has an unusually long (525bp) 5' untranslated region, which may be important for post-transcriptional regulation. an elevated level of transcription of two exoenzyme genes, pelcand celv, was observed in the ... | 1999 | 11207775 |
| global regulators expa (gaca) and kdgr modulate extracellular enzyme gene expression through the rsma-rsmb system in erwinia carotovora subsp. carotovora. | the production of the main virulence determinants, the extracellular plant cell wall-degrading enzymes, and hence virulence of erwinia carotovora subsp. carotovora is controlled by a complex regulatory network. one of the global regulators, the response regulator expa, a gaca homolog, is required for transcriptional activation of the extracellular enzyme genes of this soft-rot pathogen. to elucidate the mechanism of expa control as well as interactions with other regulatory systems, we isolated ... | 2001 | 11497464 |
| hexa of erwinia carotovora ssp. carotovora strain ecc71 negatively regulates production of rpos and rsmb rna, a global regulator of extracellular proteins, plant virulence and the quorum-sensing signal, n-(3-oxohexanoyl)-l-homoserine lactone. | the soft-rotting bacterium, erwinia carotovora ssp. carotovora (e. c. carotovora), produces an array of extracellular enzymes (= exoenzymes), including pectate lyase (pel), polygalacturonase (peh), cellulase (cel) and protease (prt), as well as harpinecc, the elicitor of hypersensitive reaction (hr). the production of these exoenzymes and harpinecc responds to plant products and the quorum-sensing signal [n-(3-oxohexanoyl)-l-homoserine lactone; ohl] and is subject to both transcriptional and pos ... | 2000 | 11220306 |
| functional characterization of a novel xylanase from a corn strain of erwinia chrysanthemi. | a beta-1,4-xylan hydrolase (xylanase a) produced by erwinia chrysanthemi d1 isolated from corn was analyzed with respect to its secondary structure and enzymatic function. the ph and temperature optima for the enzyme were found to be ph 6.0 and 35 degrees c, with a secondary structure under those conditions that consists of approximately 10 to 15% alpha-helices. the enzyme was still active at temperatures higher than 40 degrees c and at phs of up to 9.0. the loss of enzymatic activity at tempera ... | 2001 | 11222610 |
| effects of the two-component system comprising gaca and gacs of erwinia carotovora subsp. carotovora on the production of global regulatory rsmb rna, extracellular enzymes, and harpinecc. | posttranscriptional regulation mediated by the regulator of secondary metabolites (rsm) rsma-rsmb pair is the most important factor in the expression of genes for extracellular enzymes and harpinecc in erwinia carotovora subsp. carotovora. rsma is a small rna-binding protein, which acts by lowering the half-life of a mrna species. rsmb specifies an untranslated regulatory rna and neutralizes the rsma effect. it has been speculated that gaca-gacs, members of a two-component system, may affect gen ... | 2001 | 11310739 |
| new series of vectors for phage display and prokaryotic expression of proteins. | | 2001 | 11314251 |
| soxr-dependent response to oxidative stress and virulence of erwinia chrysanthemi: the key role of sufc, an orphan abc atpase. | erwinia chrysanthemi causes soft-rot disease in a great variety of plants. in addition to the depolymerizing activity of plant cell wall-degrading enzymes, iron acquisition and resistance to oxidative stress contribute greatly to the virulence of this pathogen. here, we studied the pin10 locus originally thought to encode new virulence factors. the sequence analysis revealed six open reading frames that were homologous to the escherichia coli sufa, sufb, sufc, sufd, sufs and sufe genes. sequence ... | 2001 | 11251816 |
| osmoregulated periplasmic glucans of erwinia chrysanthemi. | we report the initial characterization of the osmoregulated periplasmic glucans (opgs) of erwinia chrysanthemi. opgs are intrinsic components of the bacterial envelope necessary to the pathogenicity of this phytopathogenic enterobacterium (f. page, s. altabe, n. hugouvieux-cotte-pattat, j.-m. lacroix, j. robert-baudouy and j.-p. bohin, j. bacteriol. 183:0000-0000, 2001 [companion in this issue]). opgs were isolated by trichloracetic acid treatment and gel permeation chromatography. the synthesis ... | 2001 | 11325941 |
| osmoregulated periplasmic glucan synthesis is required for erwinia chrysanthemi pathogenicity. | erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants. osmoregulated periplasmic glucans (opgs) are intrinsic components of the gram-negative bacterial envelope. we cloned the opggh operon of e. chrysanthemi, encoding proteins involved in the glucose backbone synthesis of opgs, by complementation of the homologous locus mdogh of escherichia coli. opgg and opgh show a high level of similarity with mdog and mdoh, respectively, and mutations in ... | 2001 | 11325942 |
| the pdz domain of outc and the n-terminal region of outd determine the secretion specificity of the type ii out pathway of erwinia chrysanthemi. | the plant pathogens erwinia chrysanthemi and erwinia carotovora secrete multiple exoproteins by a type ii pathway, the out system. secretion in erwinia is species-specific: exoproteins of one species cannot be secreted by the other. we analysed the role of two components of the out system, the bitopic inner membrane protein outc and the secretin outd, in the specific recognition of secreted proteins. we demonstrated that the pdz domain of outc determines its secretion specificity towards certain ... | 2001 | 11327762 |
| isolation and characterisation of the major outer membrane protein of erwinia carotovora. | the purified major outer membrane protein (37275 da) from the psychrotrophic phytopathogen erwinia carotovora mfcl0 was structurally characterised by maldi-tof mass spectrometry, n-terminal microsequencing and dna sequence determinations, and secondary structure prediction analyses. the deduced amino acid sequence showed 76% and 72% of similarities with the serratia marcescens and escherichia coli ompa proteins respectively. dendrogram analysis allowed to point out that e. carotovora is close to ... | 2001 | 11597348 |
| innate immunity. engineering protection for plants. | | 2001 | 11256395 |
| comparative evaluation of pectolytic and proteolytic enzyme production by free and immobilized cells of some strains of the phytopathogenic erwinia chrysanthemi. | whole cells of the phytopathogenic erwinia chrysanthemi strains were immobilized in k-carrageenan and grown in high-calcium xanthomonas campestris medium containing sodium polypectate as carbon source. all the strains used survived immobilization into k-carrageenan beads. immobilized e. chrysanthemi strains displayed higher pectolytic and proteolytic enzyme activities than free cells in liquid suspension. carrageenan immobilization techniques could provide a system to mimic the conditions of e. ... | 2001 | 11687933 |
| structural basis for the activity and substrate specificity of erwinia chrysanthemi l-asparaginase. | bacterial l-asparaginases, enzymes that catalyze the hydrolysis of l-asparagine to aspartic acid, have been used for over 30 years as therapeutic agents in the treatment of acute childhood lymphoblastic leukemia. other substrates of asparaginases include l-glutamine, d-asparagine, and succinic acid monoamide. in this report, we present high-resolution crystal structures of the complexes of erwinia chrysanthemi l-asparaginase (era) with the products of such reactions that also can serve as substr ... | 2001 | 11341830 |
| an inner membrane platform in the type ii secretion machinery of gram-negative bacteria. | the type ii secretion machinery allows most gram-negative bacteria to deliver virulence factors into their surroundings. we report that in erwinia chrysanthemi, gspe (the putative ntpase), gspf, gspl and gspm constitute a complex in the inner membrane that is presumably used as a platform for assembling other parts of the secretion machinery. the gspe-gspf-gspl-gspm complex was demonstrated by two methods: (i) co-immunoprecipitation of gspe-gspf-gspl with antibodies raised against either gspe or ... | 2001 | 11266368 |
| quorum sensing controls the synthesis of virulence factors by modulating rsma gene expression in erwinia carotovora subsp. carotovora. | the plant-pathogenic bacterium erwinia carotovora subsp. carotovora (ecc) causes disease mainly by means of a number of extracellular plant cell wall-degrading enzymes (pcwdes), also referred to as virulence factors. the production of pcwdes is coordinately activated by the diffusible signal molecule n-acyl-homoserine lactone (hsl) in a population density-dependent manner ("quorum sensing"). expi is the enzyme responsible for the synthesis of hsl. the rsm system negatively regulates the producti ... | 2001 | 11361339 |
| biochemical and x-ray crystallographic studies on shikimate kinase: the important structural role of the p-loop lysine. | shikimate kinase, despite low sequence identity, has been shown to be structurally a member of the nucleoside monophosphate (nmp) kinase family, which includes adenylate kinase. in this paper we have explored the roles of residues in the p-loop of shikimate kinase, which forms the binding site for nucleotides and is one of the most conserved structural features in proteins. in common with many members of the p-loop family, shikimate kinase contains a cysteine residue 2 amino acids upstream of th ... | 2001 | 11369852 |
| beta-elimination of glucosyluronic residues during methylation of an acidic polysaccharide from erwinia chrysanthemi cu 643. | the erwinia chrysanthemi cu643 eps has a linear hexasaccharide repeating unit in which a 4-linked uronic acid residue is present. the eps was methylated by either the naoh-me2so-mei or li-dimsyl procedure. maldi-tof ms analysis of the methylated products indicates that the beta-eliminative degradation occurs during the methylation, as characterized by serial fragments of the hexasaccharide repeating units. the degradation was clearly defined from the methylation of a glucosyluronic-containing py ... | 2001 | 11376611 |
| control of exut activity for galacturonate transport by the negative regulator exur in erwinia chrysanthemi ec16. | the negative regulatory protein exur in erwinia chrysanthemi regulates expression of the galacturonate uptake (exut) and utilization (uxaa, uxab, uxac) genes. we cloned and determined the nucleotide sequence of the exur gene from e. chrysanthemi ec16. analysis of the deduced amino acid sequence indicates that this protein possesses a helix-turn-helix motif and belongs to the gntr family of transcriptional repressors. northern blot analysis and studies with transcriptional fusions of exut in wild ... | 2001 | 11386378 |
| [adsorbed receptors for erwinia carotovor subsp. carotovora macromolecular bacteriocins]. | study of nature of receptors for macromolecular bacteriocins erwinia carotovora subsp. carotovora has shown that lipopolysaccharide (lps) of cell membrane is an attaching structure for them. it has been established that enzymic treatment of lps preparation with its further deproteinization by phenol is necessary for isolation of biologically active lipopolysaccharide. the process of absorption by lps has been studied quantitatively and it has been shown that it is a low-efficient receptor as com ... | 2001 | 11392768 |
| [characteristics of bacterial lipopolysaccharides depending on extraction method]. | carbohydrate-containing biopolymers have been isolated from erwinia carotovora subsp. atroseptica 549 by two methods--the aqueous-phenol and with using physiological solution--with addition and without addition of ethylenediaminetetraacetate (edta). the biopolymers yield from the cells of bacteria are shown to depend on the extraction method. lipopolysaccharide-protein complex have been isolated by the sparing method. the purest lipopolysaccharide have been isolated by the aqueousphenol method. ... | 2000 | 11392785 |
| jasmonate-dependent induction of indole glucosinolates in arabidopsis by culture filtrates of the nonspecific pathogen erwinia carotovora. | elicitors from the plant pathogen erwinia carotovora trigger coordinate induction of the tryptophan (trp) biosynthesis pathway and trp oxidizing genes in arabidopsis. to elucidate the biological role of such pathogen-induced activation we characterized the production of secondary defense metabolites such as camalexin and indole glucosinolates derived from precursors of this pathway. elicitor induction was followed by a specific increase in 3-indolylmethylglucosinolate (igs) content, but only a b ... | 2001 | 11402212 |
| diversity of polyamine patterns in soft rot pathogens and other plant-associated members of the enterobacteriaceae. | polyamine profiles of 91 pectolytic and other plant-associated strains from 30 taxa of the enterobacteriaceae were obtained by gradient high performance liquid chromatography (hplc). pectobacterium carotovorum, basonym erwinia carotovora, contained a high amount of putrescine and less diaminopropane. diaminopropane was absent in pectobacterium chrysanthemi, basonym e. chrysanthemi, whereas cadaverine was present in addition to the major compound putrescine. this chemotaxonomic difference reflect ... | 2001 | 11403399 |
| relative effects on virulence of mutations in the sap, pel, and hrp loci of erwinia chrysanthemi. | we constructed strains of erwinia chrysanthemi ec16 with multiple mutations involving three virulence systems in this bacterium, namely pel (coding for the major pectate lyases pelabce), hrp (hypersensitive response and pathogenicity), and sap (sensitivity to antimicrobial peptides). the relative effects on virulence of those mutations have been analyzed on potato tubers and chicory leaves. in potato tubers, the sap mutation (bt105) had a greater effect in the reduction of the virulence than the ... | 2001 | 11277436 |
| nonenzymatic turnover of an erwinia carotovora quorum-sensing signaling molecule. | the production of virulence factors and carbapenem antibiotic in the phytopathogen erwinia carotovora is under the control of quorum sensing. the quorum-sensing signaling molecule, n-(3-oxohexanoyl)-l-homoserine lactone (ohhl), accumulates in log-phase culture supernatants of e. carotovora but diminishes in concentration during the stationary phase. in this study, we show that the diminution in ohhl was not due to sequestration of the ligand by the cells, although some partitioning did occur. ra ... | 2002 | 11807077 |
| backbone h(n), n, calpha, c' and cbeta assignment of the 25 kda peptide methionine sulfoxide reductase from erwinia chrysanthemi. | | 2001 | 11430764 |
| regulation of the expression of prtw::gusa fusions in erwinia carotovora subsp. carotovora. | erwinia carotovora subsp. carotovora, a gram-negative phytopathogenic bacterium, secretes an extracellular metalloprotease, prtw. previous results demonstrated that protease activity is necessary for the normal progression of disease symptoms caused by this bacterium. the present study revealed that the prtw gene constitutes an independent transcriptional unit. it is demonstrated that introduction of the prtw(+) plasmid in trans into the prtw(-) mutant restores the protease activity in this stra ... | 2002 | 11882719 |
| pyruvated galactose and oligosaccharides from erwinia chrysanthemi ech6 extracellular polysaccharide. | the acidic extracellular polysaccharide of ech6 was depolymerized by fuming hcl. the pyruvated sugars were isolated and characterized by methods that included a combination of low-pressure gel-filtration and high-ph anion-exchange chromatographies, methylation linkage analyses, mass (gc-ms and maldi-tof ms) and 1h nmr (1d and 2d) spectroscopies. the following pyruvated sugars were obtained: 4,6-o-(1-carboxyethylidene)-d-galp; 4,6-o-(1-carboxyethylidene)- alpha-d-galp-(1-->4)-beta-d-glcap-(1-->3) ... | 2001 | 11284505 |
| samsonia erythrinae gen. nov., sp. nov., isolated from bark necrotic lesions of erythrina sp., and discrimination of plant-pathogenic enterobacteriaceae by phenotypic features. | bacterial strains isolated from diseased erythrina (erythrina sp.) trees in martinique (french west indies) were studied using phenotypic tests, 16s rdna sequence analysis and dna-dna hybridization. numerical analysis of phenotypic characteristics showed that these strains formed an homogeneous phenon among plant-pathogenic enterobacteriaceae, and gave useful and updated information for the identification of these bacteria. results of dna-dna hybridization indicated that strains from erythrina b ... | 2001 | 11491325 |
| type iii secretion contributes to the pathogenesis of the soft-rot pathogen erwinia carotovora: partial characterization of the hrp gene cluster. | the virulence of soft-rot erwinia species is dependent mainly upon secreted enzymes such as pectinases, pectin lyases, and proteases that cause maceration of plant tissue. some soft-rot erwinia spp. also harbor genes homologous to the hypersensitive reaction and pathogenesis (hrp) gene cluster, encoding components of the type iii secretion system. the hrp genes are essential virulence determinants for numerous nonmacerating gram-negative plant pathogens but their role in the virulence of soft-ro ... | 2001 | 11497468 |
| cloning of the cel8y gene from pectobacterium chrysanthemi py35 and its comparison to cel genes of soft-rot pectobacterium. | the phytopathogenic pectobacterium chrysanthemi (pch) py35 secretes multiple isozymes of plant cell wall degrading enzyme cellulases. we cloned a second cel gene that encodes cellulase in pch py35. the inserted 2 kb fragment was subcloned in order to geneate ppy710 (cel8y). the structural organization of the cel8y gene consists of an open reading frame (orf) of 999 bp that encodes 332 amino acid residues with a signal peptide of 23 amino acids. the predicted amino acid sequence of cel8y was very ... | 2002 | 11911471 |
| the effect of polysialylation on the immunogenicity and antigenicity of asparaginase: implication in its pharmacokinetics. | erwinia carotovora l-asparaginase was conjugated via the epsilon-amino groups of its lysine residues with colominic acid (ca) (polysialic acid) of average molecular mass of 10 kda by reductive amination in the presence of nacnbh3. polysialylation using 50-, 100- and 250-fold molar excess ca relative to the enzyme led to an increasing proportion of the enzyme's in-amino groups (5.8, 7.6 and 11.3%, respectively) being conjugated to ca. polysialylated and native (intact) asparaginase were used to i ... | 2001 | 11292557 |
| the ybit gene of erwinia chrysanthemi codes for a putative abc transporter and is involved in competitiveness against endophytic bacteria during infection. | we investigated the role in bacterial infection of a putative abc transporter, designated ybit, of erwinia chrysanthemi ac4150. the deduced sequence of this gene showed amino acid sequence similarity with other putative abc transporters of gram-negative bacteria, such as escherichia coli and pseudomonas aeruginosa, as well as structural similarity with proteins of streptomyces spp. involved in resistance to macrolide antibiotics. the gene contiguous to ybit, designated as pab (putative antibioti ... | 2002 | 11916677 |
| transgenic plants producing the bacterial pheromone n-acyl-homoserine lactone exhibit enhanced resistance to the bacterial phytopathogen erwinia carotovora. | bacterial pheromones, mainly different homoserine lactones, are central to a number of bacterial signaling processes, including those involved in plant pathogenicity. we previously demonstrated that n-oxoacyl-homoserine lactone (ohl) is essential for quorum sensing in the soft-rot phytopathogen erwinia carotovora. in this pathogen, ohl controls the coordinate activation of genes encoding the main virulence determinants, extracellular plant cell wall degrading enzymes (pcwdes), in a cell density- ... | 2001 | 11551068 |
| cloning and characterization of an intracellular isoamylase gene from pectobacterium chrysanthemi py35. | the gene encoding an intracellular isoamylase from the pectobacterium chrysanthemi py35 was cloned in escherichia coli dh5alpha and sequenced. the isoamylase gene (amyx) had an open reading frame of 1974 bp encoding 657 amino acid residues with a calculated molecular weight of 74,151 da. the molecular weight of the enzyme was also estimated to be 74 kda by activity staining of a sds-pa gel. isoamylase from p. chrysanthemi py35 had 59% pairwise amino acid identity with glycogen debranching enzyme ... | 2001 | 11554733 |
| identification of togmnab, an abc transporter which mediates the uptake of pectic oligomers in erwinia chrysanthemi 3937. | the bacterium erwinia chrysanthemi, which causes soft rot disease on various plants, is able to use pectin as a carbon source for growth. knowledge of the critical step in pectin catabolism which allows the entry of pectic oligomers into the cells is scarce. we report here the first example of a transport system involved in the uptake of pectic oligomers. the togmnab transporter of e. chrysanthemi is a member of the atp-binding cassette (abc) superfamily. togm and togn are homologous to the inne ... | 2001 | 11555291 |
| two transporters, togt and togmnab, are responsible for oligogalacturonide uptake in erwinia chrysanthemi 3937. | erwinia chrysanthemi causes soft rot of plants by secreting pectinases which cleave pectin, a polysaccharide cementing the plant cell wall constituents. we demonstrated that two transporters mediate the uptake of the extracellularly formed oligomers in e. chrysanthemi. togmnab, a multicomponent transporter member of the atp-binding cassette (abc) superfamily, is only partially responsible for the uptake of pectic oligomers. its action is completed by that of the second transporter, togt, a membe ... | 2001 | 11555292 |
| dna inversion in the tail fiber gene alters the host range specificity of carotovoricin er, a phage-tail-like bacteriocin of phytopathogenic erwinia carotovora subsp. carotovora er. | carotovoricin er is a phage-tail-like bacteriocin produced by erwinia carotovora subsp. carotovora strain er, a causative agent for soft rot disease in plants. here we studied binding and killing spectra of carotovoricin er preparations for various strains of the bacterium (strains 645ar, ec-2, n786, and p7) and found that the preparations contain two types of carotovoricin er with different host specificities; carotovoricin era possessing a tail fiber protein of 68 kda killed strains 645ar and ... | 2001 | 11591670 |
| pehn, a polygalacturonase homologue with a low hydrolase activity, is coregulated with the other erwinia chrysanthemi polygalacturonases. | erwinia chrysanthemi 3937 secretes an arsenal of pectinolytic enzymes, including at least eight endo-pectate lyases encoded by pel genes, which play a major role in the soft-rot disease caused by this bacterium on various plants. e. chrysanthemi also produces some hydrolases that cleave pectin. three adjacent hydrolase genes, pehv, pehw, and pehx, encoding exo-poly-alpha-d-galacturonosidases, have been characterized. these enzymes liberate digalacturonides from the nonreducing end of pectin. we ... | 2002 | 11976295 |
| glycine betaine loses its osmoprotective activity in a bspa strain of erwinia chrysanthemi. | erwinia chrysanthemi insertion mutants were isolated that grew poorly specifically in the presence of glycine betaine (gb) or its analogues in high-salt media. transposon insertions were found to affect the bspa gene, which forms an operon including the psd locus coding for phosphatidylserine decarboxylase. initial gb uptake is not affected by the bspa mutation. however, in high-salt medium, its initial accumulation is followed by a reduced glucose uptake and a release of gb but not a loss of vi ... | 2001 | 11679069 |
| chrysobactin-dependent iron acquisition in erwinia chrysanthemi. functional study of a homolog of the escherichia coli ferric enterobactin esterase. | under iron limitation, the plant pathogen erwinia chrysanthemi produces the catechol-type siderophore chrysobactin, which acts as a virulence factor. it can also use enterobactin as a xenosiderophore. we began this work by sequencing the 5'-upstream region of the fct-cbsceba operon, which encodes the ferric chrysobactin receptor and proteins involved in synthesis of the catechol moiety. we identified a new iron-regulated gene (cbsh) transcribed divergently relative to the fct gene, the translate ... | 2002 | 11694506 |
| the conserved methionine residue of the metzincins: a site-directed mutagenesis study. | the metalloprotease clan of the metzincins derive their name from the presence of a conserved methionine residue that is located on the c-terminal side of the zinc-binding consensus sequence hexxhxxgxxh. this methionine residue is located in a rather divergent part of the primary sequence but is structurally very well conserved. it is located under the pyramidal base of the three histidine residues that coordinate the catalytic zinc ion and is not involved in any direct contact with the metal no ... | 2001 | 11718552 |
| protease c of erwinia chrysanthemi: the crystal structure and role of amino acids y228 and e189. | prtc, a metallo-protease secreted by erwinia chrysanthemi, is a member of the serralysin family and hence belongs to the metzincin superfamily. while the crystal structures of representatives of all metzincin subfamilies have been elucidated in the past, there is still some controversy about the reaction mechanism and the role of certain characteristic amino acids in the active centre. in this study, we probed the role of tyr228 and glu189 by site-directed mutagenesis and x-ray crystallography. ... | 2001 | 11718553 |
| hrp genes of erwinia chrysanthemi 3937 are important virulence factors. | we developed improved virulence assays for erwinia chrysanthemi 3937 on african violet varieties and devised a new method for the construction of precise bacterial gene knockouts. these methods were tested by constructing mutations in genes suspected to be involved with plant interactions. the virulence of the hrpg and hrcc mutant strains (both gene products presumed to be involved in protein secretion) was greatly reduced on leaves of semitolerant african violet varieties. an hrpn mutant strain ... | 2002 | 12036278 |
| overexpresssion of a legionella pneumophila homologue of the e. coli regulator csra affects cell size, flagellation, and pigmentation. | legionella pneumophila is an inhabitant of the aquatic environment and the causative agent of a bacterial pneumonia. we identified the presence of an l. pneumophila homologue of csra of e. coli and rsma of erwinia carotovora, genes which regulate gene expression by destabilising mrna and which have been shown to relate to environmental fitness and pathogenicity. the legionella csra was able to complement a csra-negative mutant of e. coli. overproduction of csra in l. pneumophila lead to a reduct ... | 2001 | 11727819 |
| interaction of ozone and negative air ions to control micro-organisms. | the aims of this study were to investigate the effect of ozone and/or negative air ions (nai) on the viability of bacteria. | 2002 | 12067383 |
| halogenated furanones from the red alga, delisea pulchra, inhibit carbapenem antibiotic synthesis and exoenzyme virulence factor production in the phytopathogen erwinia carotovora. | the plant pathogen erwinia carotovora regulates expression of virulence factors and antibiotic production via an n-3-oxohexanoyl-l-homoserine lactone (3-oxo-c6-hsl) dependent quorum sensing mechanism. the marine alga delisea pulchra produces halogenated furanones known to antagonise 3-oxo-c6-hsl activity. we have tested the effects of a halogenated furanone on the production of carbapenem, cellulase and protease in e. carotovora. despite differences in the regulatory mechanisms controlling carba ... | 2001 | 11728727 |
| optimization of fermentation reaction conditions for preparation of pate enzyme by erwinia carotovora ifo3830 by tfccrd method. | the fermentation conditions for preparation of polygalacturonic acid transeliminase (pate) enzyme by erwinia carotovora ifo3830 were optimized for seed ratio, vibration rate, and temperature by the tfccrd method. the results indicated that the optimum fermentation conditions for e. carotovora ifo 3830 were that seed ratio, vibration rate, and temperature were 5% v/v, 113 min(-1), and 29 degrees c, respectively. | 2001 | 11735434 |
| the oligogalacturonate-specific porin kdgm of erwinia chrysanthemi belongs to a new porin family. | the phytopathogenic gram-negative bacteria erwinia chrysanthemi secretes pectinases, which are able to degrade the pectic polymers of plant cell walls, and uses the degradation products as a carbon source for growth. we characterized a major outer membrane protein, kdgm, whose synthesis is strongly induced in the presence of pectic derivatives. the corresponding gene was characterized. analysis of transcriptional fusions showed that the kdgm expression is controlled by the general repressor of p ... | 2002 | 11773048 |
| diverse bacteria are pathogens of caenorhabditis elegans. | practically and ethically attractive as model systems, invertebrate organisms are increasingly recognized as relevant for the study of bacterial pathogenesis. we show here that the nematode caenorhabditis elegans is susceptible to a surprisingly broad range of bacteria and may constitute a useful model for the study of both pathogens and symbionts. | 2002 | 12117988 |
| microarray profiling of erwinia chrysanthemi 3937 genes that are regulated during plant infection. | microarray technology was used to identify genes in erwinia chrysanthemi 3937 that are specifically up- or down-regulated in a plant host compared with growth in laboratory culture medium. several genes were plant down-regulated, and almost all of them were homologues of well-known housekeeping genes, such as those encoding metabolic functions, oxidative phosphorylation components, and transcription or translation processes. on the other hand, almost all of the plant up-regulated genes were invo ... | 2002 | 12118877 |
| [isolation and preliminary characterization of cryptic plasmids from erwinia carotovora]. | of the fifty-two erwinia carotovora strains studied, sixteen were found to contain extrachromosomal dna (plasmids) from 2.5 to 129 kbp in size. some e. carotovora strains bore two to five different plasmids. experiments showed that the cryptic plasmids of erwinia are not responsible for their resistance to antibiotics and are not involved in the synthesis of macromolecular colicin-like carotovoricins. at the same time, one of the e. carotovora strains, 13a, augmented the production of carotovori ... | 2001 | 11785137 |
| direct process integration of cell disruption and fluidised bed adsorption in the recovery of labile microbial enzymes. | the practical feasibility and generic applicability of the direct integration of cell disruption by bead milling with the capture of intracellular products by fluidised bed adsorption has been demonstrated. pilot-scale purification of the enzyme l-asparaginase from unclarified erwinia chrysanthemi disruptates exploiting this novel approach yielded an interim product which rivalled or bettered that produced by the current commercial process employing discrete operations of alkaline lysis, centrif ... | 2001 | 11787801 |
| characterization of indigoidine biosynthetic genes in erwinia chrysanthemi and role of this blue pigment in pathogenicity. | in the plant-pathogenic bacterium erwinia chrysanthemi production of pectate lyases, the main virulence determinant, is modulated by a complex network involving several regulatory proteins. one of these regulators, pecs, also controls the synthesis of a blue pigment identified as indigoidine. since production of this pigment is cryptic in the wild-type strain, e. chrysanthemi ind mutants deficient in indigoidine synthesis were isolated by screening a library of tn5-b21 insertions in a pecs mutan ... | 2002 | 11790734 |
| evaluation of transgenic tomato plants expressing an additional phytoene synthase in a fruit-specific manner. | phytoene synthase from the bacterium erwinia uredovora (crtb) has been overexpressed in tomato (lycopersicon esculentum mill. cv. ailsa craig). fruit-specific expression was achieved by using the tomato polygalacturonase promoter, and the crtb protein was targeted to the chromoplast by the tomato phytoene synthase-1 transit sequence. total fruit carotenoids of primary transformants (t(0)) were 2-4-fold higher than the controls, whereas phytoene, lycopene, beta-carotene, and lutein levels were in ... | 2002 | 11805345 |
| activity enhancement of cel5z from pectobacterium chrysanthemi py35 by removing c-terminal region. | the phytopathogenic bacterium pectobacteium chrysanthemi py35 secretes cel5z endoglucanase belonging to the glycoside hydrolase family 5 of ec 3.2.1.4. the mutation of cel5z::omega gene was constructed by cloning the 2.0-kb smai fragment containing the streptomycin/spectinomycin-resistance gene of php45(omega) into the bali site of ppy100. the insertion of omega fragment generated a new stop codon, removing the ser/thr-rich linker region and the cellulose binding domain (cbd) in the c-terminal r ... | 2002 | 11846423 |
| altered lignin structure and resistance to pathogens in spi 2-expressing tobacco plants. | the physiological role of the norway spruce [ picea abies (l.) karst.] spi 2 gene, encoding a defense-related cationic peroxidase was examined in transgenic tobacco (nicotiana tabacum l.). expression of spi 2, under control of the 35s promoter, in tobacco plants resulted in higher total peroxidase activities. the phenotype of the spi 2-transformed lines was normal. the spi 2-transformed lines displayed lignin levels similar to levels in the control line, but with some alteration in lignin histoc ... | 2002 | 11882939 |
| type ii protein secretion in gram-negative pathogenic bacteria: the study of the structure/secretion relationships of the cellulase cel5 (formerly egz) from erwinia chrysanthemi. | erwinia chrysanthemi, a gram-negative plant pathogen, secretes the cellulase cel5 (formerly egz) via the type ii secretion pathway (referred to as out). cel5 is composed of two domains, a large n-terminal catalytic domain (390 amino acid residues) and a small c-terminal cellulose-binding domain (62 amino acid residues) separated by a linker region. a combination of mutagenesis and structural analysis permitted us to investigate the structure/secretion relationships with respect to the catalytic ... | 2001 | 11501995 |
| enhanced disease resistance conferred by expression of an antimicrobial magainin analog in transgenic tobacco. | magainins are a group of short peptides originally isolated from frog skin and thought to function as a natural defense mechanism against infection due to their antimicrobial properties. the engineered magainin analog peptide myp30 was found to inhibit spore germination of the oomycete, peronospora tabacina (adam) in vitro, and the growth of a bacterial pathogen erwinia carotovora subsp. carotovora (jones). transgenic tobacco (nicotiana tabacum l.) plants expressing myp30 were evaluated for resi ... | 2001 | 11525522 |
| h-ns-dependent activation of pectate lyases synthesis in the phytopathogenic bacterium erwinia chrysanthemi is mediated by the pect repressor. | production of the main virulence determinant pectate lyases (pels) of the phytopathogenic bacterium erwinia chrysanthemi is modulated by a complex regulatory network involving the repressor proteins kdgr, pecs and pect and the activator systems pir, expi-expr and crp. of these regulators, crp and pect are particularly important since the absence of crp or a slight overproduction of pect leads to a drastic reduction in synthesis of pel species. recently, it has been shown that production of pel s ... | 2002 | 11929528 |
| crystal structure of plant pectin methylesterase. | pectin is a principal component in the primary cell wall of plants. during cell development, pectin is modified by pectin methylesterases to give different properties to the cell wall. this report describes the first crystal structure of a plant pectin methylesterase. the beta-helical structure embodies a central cleft, lined by several aromatic residues, that has been deduced to be suitable for pectin binding. the active site is found at the center of this cleft where asp157 is suggested to act ... | 2002 | 11943159 |
| [study of population dissociation of collection strains of erwinia carotovora]. | unusual dissociants of erwinia carotovora subsp. atroseptica (eat) population that emerge with high frequency (18-94%) during long-term storage of cultures were found. the dissociants (poe-phenotype) differ from parental forms by slow growth and long development of the colour of colonies on emb agar though they are not lac-mutants. more than 60% of poe-mutants of strain eat 39a are characterized by 8- and 150-fold decrease of stability to erythromycin and oleandomicin, correspondingly. they are ... | 2002 | 11944340 |
| response of endophytic bacterial communities in potato plants to infection with erwinia carotovora subsp. atroseptica. | the term endophyte refers to interior colonization of plants by microorganisms that do not have pathogenic effects on their hosts, and various endophytes have been found to play important roles in plant vitality. in this study, cultivation-independent terminal restriction fragment length polymorphism analysis of 16s ribosomal dna directly amplified from plant tissue dna was used in combination with molecular characterization of isolates to examine the influence of plant stress, achieved by infec ... | 2002 | 11976096 |
| coupling of iron assimilation and pectinolysis in erwinia chrysanthemi 3937. | two major virulence determinants of the plant-pathogenic enterobacterium erwinia chrysanthemi strain 3937 are the production of pectate lyase enzymes that degrade plant cell walls and expression of two high-affinity iron uptake systems mediated by two structurally unrelated siderophores, chrysobactin and achromobactin. low iron availability is a signal that triggers transcription of the genes encoding pectate lyases peld and pele as well as that of genes involved in iron transport. this metallor ... | 2002 | 12423024 |
| the refolding of type ii shikimate kinase from erwinia chrysanthemi after denaturation in urea. | shikimate kinase was chosen as a convenient representative example of the subclass of alpha/beta proteins with which to examine the mechanism of protein folding. in this paper we report on the refolding of the enzyme after denaturation in urea. as shown by the changes in secondary and tertiary structure monitored by far uv circular dichroism (cd) and fluorescence, respectively, the enzyme was fully unfolded in 4 m urea. from an analysis of the unfolding curve in terms of the two-state model, the ... | 2002 | 11985590 |
| sample sequencing of a selected region of the genome of erwinia carotovora subsp. atroseptica reveals candidate phytopathogenicity genes and allows comparison with escherichia coli. | genome sequencing is making a profound impact on microbiology. currently, however, only one plant pathogen genome sequence is publicly available and no genome-sequencing project has been initiated for any species of the genus erwinia, which includes several important plant pathogens. this paper describes a targeted sample sequencing approach to study the genome of erwinia carotovora subsp. atroseptica (eca), a major soft-rot pathogen of potato. a large insert dna (approx. 115 kb) library of eca ... | 2002 | 11988510 |
| temperature-dependent production of carotovoricin er and pectin lyase in phytopathogenic erwinia carotovora subsp. carotovora er. | the production of pectin lyase (pnl) and carotovoricin (ctv), as well as cell lysis in the plant-pathogenic bacterium erwinia carotovora subsp. carotovora er are induced by mitomycin c. here, pnl and ctv production and cell lysis were found to be temperature-dependent. the optimal temperature for pnl production was 30 degrees c. however, the optimal temperature for both ctv production and cell lysis was 23 degrees c, at which pnl production was reduced to 47% of the maximum. these data suggest t ... | 2002 | 11999425 |
| natural variability in the arabidopsis response to infection with erwinia carotovora subsp. carotovora. | the natural variation in the response of arabidopsis thaliana (l.) heynh. to erwinia carotovora subsp. carotovora has been studied in seven ecotypes and two mutants. the susceptibility of all the plant types was investigated by (i) macroscopic symptoms, (ii) fluorescence microscopy using green fluorescent protein (gfp) and (iii) bacterial growth in planta. although all the plants were susceptible to the bacterium, there was no correlation in the degree of infection as ascertained by the three me ... | 2002 | 12029469 |
| structure of pectate lyase a: comparison to other isoforms. | pectate lyase a is a virulence factor secreted by the plant-pathogenic bacteria erwinia chrysanthemi. the enzyme cleaves the glycosidic bond of pectate polymers by a calcium-dependent beta-elimination mechanism. the crystal structure of pectate lyase a from e. chrysanthemi ec16 has been determined in two crystal forms, monoclinic c2 to 1.8 a and rhombohedral r3 to 2.1 a. the protein structure is compared with two other pectate lyase isoforms from e. chrysanthemi ec16, pectate lyase c and pectate ... | 2002 | 12037303 |
| molecular model of shikimate kinase from mycobacterium tuberculosis. | tuberculosis (tb) resurged in the late 1980s and now kills approximately 3 million people a year. the reemergence of tuberculosis as a public health threat has created a need to develop new anti-mycobacterial agents. the shikimate pathway is an attractive target for herbicides and anti-microbial agents development because it is essential in algae, higher plants, bacteria, and fungi, but absent from mammals. homologs to enzymes in the shikimate pathway have been identified in the genome sequence ... | 2002 | 12083781 |
| altering plant-microbe interaction through artificially manipulating bacterial quorum sensing. | many bacteria regulate diverse physiological processes in concert with their population size. bacterial cell-to-cell communication utilizes small diffusible signal molecules, which the bacteria both produce and perceive. the bacteria couple gene expression to cell density by eliciting a response only when the signalling molecules reach a critical threshold (a point at which the population is said to be 'quorate'). the population as a whole is thus able to modify its behaviour as a single unit. a ... | 2002 | 12096736 |
| rsma and the quorum-sensing signal, n-[3-oxohexanoyl]-l-homoserine lactone, control the levels of rsmb rna in erwinia carotovora subsp. carotovora by affecting its stability. | rsma (for regulator of secondary metabolism), rsmc, and rsmb rna, the components of a posttranscriptional regulatory system, control extracellular protein production and pathogenicity in erwinia carotovora subsp. carotovora. rsma, an rna binding protein, acts as a negative regulator by promoting message decay. rsmb rna, on the other hand, acts as a positive regulator by neutralizing the effect of rsma. rsmc modulates the levels of rsma and rsmb rna by positively regulating rsma and negatively co ... | 2002 | 12107125 |
| the crystal structure of anthranilate phosphoribosyltransferase from the enterobacterium pectobacterium carotovorum. | the structure of anthranilate phosphoribosyltransferase from the enterobacterium pectobacterium carotovorum has been solved at 2.4 a in complex with mn(2+)-pyrophosphate, and at 1.9 a without ligands. the enzyme structure has a novel phosphoribosyltransferase (prt) fold and displays close homology to the structures of pyrimidine nucleoside phosphorylases. the enzyme is a homodimer with a monomer of 345 residues. each monomer consists of two subdomains, alpha and alpha/beta, which form a cleft co ... | 2002 | 12123839 |
| [temperate bacteriophage zf40 of erwinia carotovora: phage particle structure and dna restriction analysis]. | structural organization of the temperate bacteriophage zf40 of erwinia carotovora was studied. phage zf40 proved to be a typical member of the myoviridae family (morphotype a1). phage particles consist of an isometric head 58.3 nm in diameter and a contractile 86.3-nm-long tail with a complex basal plate and short tail fibers (31.5 nm). phage tail sheath, a truncated cone in shape, is characterized by specific packaging of structural subunits. the zf40 phage genome is 45.8 kb in size, as determi ... | 2002 | 11910811 |
| [study of erwinia carotovora phage resistance with the use of temperate bacteriophage zf40]. | the causes of the unique phage resistance of the pectinolytic phytopathogenic strains of erwinia carotovora were studied with the use of temperate bacteriophage zf40. it was shown that, in these bacteria, the bacteriophage-cell interaction can be substantially blocked at the adsorption level. an adequate indicator for studying the temperate bacteriophages of erwinias was developed on the basis of mutants resistant to macromolecular bacteriocins. various restriction-modification systems, which in ... | 2002 | 11910812 |
| application of amplified fragment length polymorphism fingerprinting for taxonomy and identification of the soft rot bacteria erwinia carotovora and erwinia chrysanthemi. | the soft rot bacteria erwinia carotovora and erwinia chrysanthemi are important pathogens of potato and other crops. however, the taxonomy of these pathogens, particularly at subspecies level, is unclear. an investigation using amplified fragment length polymorphism (aflp) fingerprinting was undertaken to determine the taxonomic relationships within this group based on their genetic relatedness. following cluster analysis on the similarity matrices derived from the aflp gels, four clusters (clus ... | 2002 | 11916661 |
| a putative three-dimensional targeting motif of polygalacturonase (peha), a protein secreted through the type ii (gsp) pathway in erwinia carotovora. | intramolecular information specifying protein secretion through the type ii (gsp) pathway of gram-negative bacteria was investigated. two regions of the polygalacturonase (peha) of erwinia carotovora containing residues proposed to be included in a targeting motif were located, one close to the c-terminus between residues 342 and 369 and another between residues 84 and 135 in the large central loops. the regions were required together to promote secretion. further residues in the middle of the p ... | 2002 | 11929517 |
| [defective lysogeny in erwinia carotovora]. | the electron microscopic study of several erwinia carotovora strains showed that the sos-induced cells of this pectolytic phytopathogenic bacterium produce particular phage parts (tails, heads, and baseplates) but do not assemble them into fully functional phage particles. e. carotovora cells produced several times greater amounts of phage tails in response to induction by mitomycin c than in response to induction by nalidixic acid. the tails were 128-192 nm in length and 13-21 nm in diameter. p ... | 2002 | 12138758 |
| genes encoding the n-acyl homoserine lactone-degrading enzyme are widespread in many subspecies of bacillus thuringiensis. | gram-negative bacteria can communicate with each other by n-acyl homoserine lactones (ahls), which are quorum-sensing autoinducers. recently, the aiia gene (encoding an enzyme catalyzing the degradation of ahl) has been cloned from bacillus sp. strain 240b1. during investigations in the course of the ongoing bacillus thuringiensis subsp. morrisoni genome project, an aiia homologue gene in the genome sequence was found. these results led to consideration of the possibility of the widespread exist ... | 2002 | 12147491 |
| inhibition of the plastidic atp/adp transporter protein primes potato tubers for augmented elicitation of defense responses and enhances their resistance against erwinia carotovora. | tubers of transgenic potato (solanum tuberosum) plants with decreased activity of the plastidic atp/adp transporter aatp1 display reduced levels of starch, modified tuber morphology, and altered concentrations of primary metabolites. here, we demonstrate that the spontaneous production of hydrogen peroxide, the endogenous content of salicylic acid, and the levels of mrnas of various defense-related genes are similar in tuber discs of wild-type and aatp1(st) antisense plants. however, upon challe ... | 2002 | 12177473 |
| quorum sensing in plant-associated bacteria. | n-acyl homoserine lactone (ahl)-mediated quorum sensing by bacteria regulates traits that are involved in symbiotic, pathogenic and surface-associated relationships between microbial populations and their plant hosts. recent advances demonstrate deviations from the classic luxr/luxi paradigm, which was first developed in vibrio. for example, luxr homologs can repress as well as activate gene expression, and non-ahl signals and signal mimics can affect the expression of genes that are controlled ... | 2002 | 12179960 |
| constitutive expression of hrap gene in transgenic tobacco plant enhances resistance against virulent bacterial pathogens by induction of a hypersensitive response. | hypersensitive response-assisting protein (hrap) has been previously reported as an amphipathic plant protein isolated from sweet pepper that intensifies the harpin(pss)-mediated hypersensitive response (hr). the hrap gene has no appreciable similarity to any other known sequences, and its activity can be rapidly induced by incompatible pathogen infection. to assess the function of the hrap gene in plant disease resistance, the camv 35s promoter was used to express sweet pepper hrap in transgeni ... | 2002 | 12182333 |
| [method for studying horizontal transfer of plasmids in erwinia carotovora]. | a simple method to determine frequency characteristics of the horizontal transfer of antibiotic resistance by transconjugative plasmids of various incompatibility groups into erwinia carotovora strains has been developed. the proposed method for selection of e. carotovora transconjugates provides for the use of selective medium with pectin and corresponding antibiotic, which permits carrying out reliable counterselection of the donor (escherichia, salmonella). the proposed method helped to study ... | 2002 | 12190030 |
| regulation of erwinia carotovora hrpl(ecc) (sigma-l(ecc)), which encodes an extracytoplasmic function subfamily of sigma factor required for expression of the hrp regulon. | in erwinia carotovora subsp. carotovora (ecc) strain 71 (ecc71), hrpl(ecc), an alternate sigma factor of the extracytoplasmic function subfamily, plays a central role in the expression of the hrp (hypersensitive reaction and pathogenicity) regulon. we document here that sigma-54 (rpon) is required for full expression of hrpl(ecc) and that hrps, in conjunction with sigma-54, activates hrpl(ecc) transcription. we also made the novel observation that integration host factor is required for the acti ... | 2002 | 12236604 |
| [in vitro self assembly of supermolecular structures after spontaneous disassembly of carotovoricins]. | the self-assembly of supramolecular structures (empty sheaths and polysheaths of the macromolecular erwinia carotovora bacteriocins) was studied by electron microscopy in the course of 1- to 2-year incubation of phage particles at 4 degrees c. this study showed that the empty sheaths and polysheaths of the bacteriocins of eight e. carotovora strains spontaneously assemble at the self-assembly centers (or crystallization centers), which have a diameter of 26-65 nm and contain a dense proteinaceou ... | 2002 | 12244715 |
| heca, a member of a class of adhesins produced by diverse pathogenic bacteria, contributes to the attachment, aggregation, epidermal cell killing, and virulence phenotypes of erwinia chrysanthemi ec16 on nicotiana clevelandii seedlings. | erwinia chrysanthemi is representative of a broad class of bacterial pathogens that are capable of inducing necrosis in plants. the e. chrysanthemi ec16 heca gene predicts a 3,850-aa member of the bordetella pertussis filamentous hemagglutinin family of adhesins. a hecatn7 mutant was reduced in virulence on nicotiana clevelandii seedlings after inoculation without wounding. epifluorescence and confocal laser-scanning microscopy observations of heca and wild-type cells expressing the green fluore ... | 2002 | 12271135 |