| bacillus subtilis bs 107 as an antagonist of potato blackleg and soft rot bacteria. | antimicrobial substances were produced by bacillus subtilis bs 107 in a defined medium and isolated from culture filtrate by precipitation at ph 2.5. active fractions were extracted in ethyl acetate, acetone, and 80% ethanol and purified by thin-layer chromatography (tlc) on silica gel plates developed with an ethanol-water mixture (2:1, v/v). in each case, a band with a rf of 0.75 formed an inhibitory zone when the tlc plates were placed in contact with agar seeded with test cultures of the erw ... | 1998 | 9830107 |
| solution structure of the cellulose-binding domain of the endoglucanase z secreted by erwinia chrysanthemi. | two-dimensional proton nuclear magnetic resonance spectroscopy has been used to determine the three-dimensional structure of the 62 amino acid c-terminal cellulose-binding domain (cbd) of the endoglucanase z (cbdegz), secreted by erwinia chrysanthemi. an experimental data set comprising 958 interproton noe-derived restraints was used to calculate 23 structures. the calculated structures have an average root-mean-square deviation between cys4 and cys61 of 0.91 +/- 0.11 a for backbone atoms and 1. ... | 1997 | 9405041 |
| the pecm protein is necessary for the dna-binding capacity of the pecs repressor, one of the regulators of virulence-factor synthesis in erwinia chrysanthemi. | the pecs regulatory locus is responsible for the down-expression of many virulence genes in erwinia chrysanthemi. this locus consists of two genes, pecs and pecm, divergently transcribed. genetic evidence indicates that the pecm protein modulates the regulatory activity of pecs. purification and characterization of pecs, expressed either from e. coli, from the wild-type e. chrysanthemi strain or from a pecm mutant, showed that the pecs protein produced in these three genetic backgrounds displays ... | 1997 | 9311123 |
| specific interaction between outd, an erwinia chrysanthemi outer membrane protein of the general secretory pathway, and secreted proteins. | outd is an outer membrane component of the main terminal branch of the general secretory pathway (gsp) in erwinia chrysanthemi. we analyzed the interactions of outd with other components of the gsp (out proteins) and with secreted proteins (pelb, egz and pema). outd is stabilized by its interaction with another gsp component, outs. the 62 c-terminal amino acids of outd are necessary for this interaction. in vivo formation of outd multimers, up to tetramers, was proved after the dissociation in m ... | 1997 | 9214618 |
| antagonistic effect of crp and kdgr in the transcription control of the erwinia chrysanthemi pectinolysis genes. | the main virulence factors of the phytopathogenic bacteria erwinia chrysanthemi are pectinases that cleave pectin, a major constituent of the plant cell wall. the cyclic amp receptor protein (crp) was identified as the main activator of the pectinolysis genes. gel shift and dnase i footprinting experiments showed that the purified e. chrysanthemi crp protein binds specifically to the promoter regions of seven pectinolysis genes (pelb, pelc, peld, pele, ogl, kdui and kdgt) whose expression is pos ... | 1997 | 9426143 |
| crystal structure of polygalacturonase from erwinia carotovora ssp. carotovora. | the crystal structure of the 40-kda endo-polygalacturonase from erwinia carotovora ssp. carotovora was solved by multiple isomorphous replacement and refined at 1.9 a to a conventional crystallographic r-factor of 0.198 and rfree of 0.239. this is the first structure of a polygalacturonase and comprises a 10 turn right-handed parallel beta-helix domain with two loop regions forming a "tunnel like" substrate-binding cleft. sequence conservation indicates that the active site of polygalacturonase ... | 1998 | 9733763 |
| phylogenetic position of phytopathogens within the enterobacteriaceae. | the almost complete 16s rdna sequences of twenty nine plant-associated strains, representing species of the genera erwinia, pantoea and enterobacter were determined and compared with those of other members of the enterobacteriaceae. the species of the genus erwinia may be divided into three phylogenetic groups. cluster i represents the true erwinias and comprises e. amylovora, e. mallotivora, e. persicinus, e. psidii, e. rhapontici and e. tracheiphila. we propose to unite the species of cluster ... | 1998 | 9779605 |
| l-asparagine-depletion: another opinion. | | 1997 | 9093736 |
| a cloned erwinia chrysanthemi hrp (type iii protein secretion) system functions in escherichia coli to deliver pseudomonas syringae avr signals to plant cells and to secrete avr proteins in culture. | the hrp (type iii protein secretion) system is essential for the plant parasitic ability of pseudomonas syringae and most gram-negative bacterial plant pathogens. avrb and avrpto are two p. syringae proteins that have biological activity when produced via heterologous gene expression inside plant cells or when produced by hrp+ bacteria. avr-like proteins, presumably injected by the hrp system on bacterial contact with plant cells, appear to underlie pathogenic interactions, but none has been obs ... | 1998 | 9707625 |
| identification and cloning of an erwinia carotovora subsp. carotovora bacteriocin regulator gene by insertional mutagenesis. | avirulent erwinia carotovora subsp. carotovora cge234-m403 produces two types of bacteriocin. for the purpose of cloning the bacteriocin genes of strain cge234m403, a spontaneous rifampin-resistant mutant of this strain, m-rif-11-2, was isolated. by tn5 insertional mutagenesis using m-rif-11-2, a mutant, tm01a01, which produces the high-molecular-weight bacteriocin but not the low-molecular-weight bacteriocin was obtained. by thermal asymmetric interlaced pcr, the dna sequence from the tn5 inser ... | 1999 | 10074096 |
| the interaction of shikimate kinase from erwinia chrystanthemi with substrates. | | 1997 | 9450055 |
| the oxyr gene from erwinia carotovora: cloning, sequence analysis and expression in escherichia coli. | homologs of the escherichia coli oxyr gene were identified in several erwinia species, using a combination of pcr and southern hybridization analysis. the oxyr gene from erwinia carotovora was isolated on a cosmid clone and characterized. the gene and deduced gene product shared high level sequence identity with their e. coli counterparts (78 and 89% identity, respectively). in e. coli, the oxyr gene is a transcriptional activator that, under oxidizing conditions, induces expression of a set of ... | 1998 | 9809430 |
| the hrpc and hrpn operons of erwinia chrysanthemi ec16 are flanked by plca and homologs of hemolysin/adhesin genes and accompanying activator/transporter genes. | the hrpc operon of erwinia chrysanthemi ec16 encodes five genes conserved in erwinia amylovora and pseudomonas syringae. mutagenesis indicated that hrcc is required for elicitation of the hypersensitive reaction in tobacco leaves. the unexpected presence of plca and homologs of hemolysin/activator genes in the regions flanking the hrcc and hrpn operons is reported. | 1998 | 9612954 |
| engineering, expression and biochemical characterization of the hemoglobin domain of a erwinia chrysanthemi flavohemoprotein. | an artificial hemoglobin-like domain has been constructed by engineering the gene coding for the multi-domain flavohemoprotein from the bacterium erwinia chrysanthemi. this domain was designed by molecular modelling, cloned and over-expressed in escherichia coli. the holo-protein was obtained in large quantities after extraction from inclusion bodies and refolding in presence of alkaline hemin. the purified 140-residue domain was studied and characterized to gain new insights into the biochemica ... | 1998 | 9654075 |
| functional characterization of the erwinia chrysanthemi outs protein, an element of a type ii secretion system. | secretion of pectate lyases and a cellulase occurs in erwinia chrysanthemi through a type ii secretion machinery, the out system. proper insertion of the secretin outd in the outer membrane requires the presence of outs. outs is an outer-membrane lipoprotein that interacts directly with outd. using ligand-blotting experiments, it has been shown that this interaction requires at least the 62 c-terminal amino acids of outd. when this domain was added to the c-terminal extremity of the secreted pec ... | 1998 | 9846757 |
| "horizontal" gene transfer from a transgenic potato line to a bacterial pathogen (erwinia chrysanthemi) occurs--if at all--at an extremely low frequency. | the frequency of possible "horizontal" gene transfer between a plant and a tightly associated bacterial pathogen was studied in a model system consisting of transgenic solanum tuberosum, containing a beta-lactamase gene linked to a pbr322 origin of replication, and erwinia chrysanthemi. this experimental system offers optimal conditions for the detection of possible horizontal gene transfer events, even when they occur at very low frequency. horizontal gene transfer was not detected under condit ... | 1995 | 9636282 |
| the pect repressor interacts with regulatory regions of pectate lyase genes in erwinia chrysanthemi. | erwinia chrysanthemi is a broad host range phytopathogenic enterobacterium responsible for soft-rot disease of many plant species. the pect gene encodes a repressor that negatively regulates the expression of virulence factors, such as pectinases, motility or exopolysaccharide synthesis. the cloned pect gene was overexpressed using a phage t7 system. the purification of pect involved the use of a tsk-heparin column and delivered the pect protein that was purified to near homogeneity. the purifie ... | 1998 | 9804934 |
| kdgrecc negatively regulates genes for pectinases, cellulase, protease, harpinecc, and a global rna regulator in erwinia carotovora subsp. carotovora. | erwinia carotovora subsp. carotovora produces extracellular pectate lyase (pel), polygalacturonase (peh), cellulase (cel), and protease (prt). the concerted actions of these enzymes largely determine the virulence of this plant-pathogenic bacterium. e. carotovora subsp. carotovora also produces harpinecc, the elicitor of the hypersensitive reaction. we document here that kdgrecc (kdg, 2-keto-3-deoxygluconate; kdgr, general repressor of genes involved in pectin and galacturonate catabolism), a ho ... | 1999 | 10198003 |
| evidence against the double-arginine motif as the only determinant for protein translocation by a novel sec-independent pathway in escherichia coli. | proteins which are synthesized with a signal peptide containing a 'double-arginine' motif may be translocated across the bacterial cytoplasmic membrane by a mechanism that is different from the known sec and signal recognition particle pathways. the function of the double-arginine motif as a determinant for this novel pathway was studied by expressions of gene constructs coding for the high potential iron-sulfur protein (hipip) from chromatium vinosum d in escherichia coli. when the protein was ... | 1998 | 9682482 |
| enhancement of expression and apparent secretion of erwinia chrysanthemi endoglucanase (encoded by celz) in escherichia coli b. | escherichia coli b has been engineered as a biocatalyst for the conversion of lignocellulose into ethanol. previous research has demonstrated that derivatives of e. coli b can produce high levels of erwinia chrysanthemi endoglucanase (encoded by celz) as a periplasmic product and that this enzyme can function with commercial fungal cellulase to increase ethanol production. in this study, we have demonstrated two methods that improve celz expression in e. coli b. initially, with a low-copy-number ... | 1999 | 10347024 |
| characterization of a periplasmic peptidyl-prolyl cis-trans isomerase in erwinia chrysanthemi. | the main determinant of the plant pathogen erwinia chrysanthemi virulence is the production of extracellular enzymes, mainly pectate lyases. adjacent to a pectate lyase encoding locus, we identified the gene rota supposed to encode a folding catalyst. overproduction of the protein and assay of activity using a synthetic substrate, confirmed that rota encodes a periplasmic peptidyl-prolyl cis-trans isomerase. rota disruption provokes no change in cell morphology, cell viability, growth rate or st ... | 1997 | 9418240 |
| influence of soft rot bacteria on growth of listeria monocytogenes on potato tuber slices. | growth of listeria monocytogenes on potato tuber slices and its interaction with four representative species of soft rot bacteria (pseudomonas fluorescens, p. viridiflava, erwinia carotovora subsp. carotovora, and xanthomonas campestris) were investigated. when potato tuber slices were inoculated with one of two l. monocytogenes strains (scott a and atcc 15313), an increase in numbers of 3 to 4 logs per gram of tissue was observed with samples that were stored at 20 degrees c for 6 days. however ... | 1999 | 10419206 |
| characterization of a novel rna regulator of erwinia carotovora ssp. carotovora that controls production of extracellular enzymes and secondary metabolites. | the enterobacterium erwinia carotovora ssp. carotovora strain 71 (hereafter ecc71) produces extracellular enzymes such as pectate lyase isozymes (pels), cellulase (cel), polygalacturonase (peh) and protease (prt). these enzymes degrade plant cell wall components and are largely responsible for the elicitation of soft-rot diseases in plants and plant products. ecc71 also produces harpinecc, the elicitor of hypersensitive reaction (hr) and the quorum-sensing signal, n-(3-oxohexanoyl)-l-homoserine ... | 1998 | 9701816 |
| asparaginases: where do we go from here? | | 1999 | 10029804 |
| iron regulation and pathogenicity in erwinia chrysanthemi 3937: role of the fur repressor protein. | low iron availability is a triggering signal for coordinated expression of the genes encoding pectate lyases pelb, pelc, peld, and pele, and chrysobactin iron transport functions, which are two main determinants of phytopathogenicity of the erwinia chrysanthemi strain 3937. the possible implication of the ferric uptake regulation (fur) protein in this process was investigated. the e. chrysanthemi fur gene was cloned by functional complementation of an escherichia coli fur mutant and sequenced. t ... | 1999 | 9926414 |
| erwinia metalloprotease permease: aspects of secretion pathway and secretion functions. | | 1998 | 9711547 |
| conditional mutations in oute and outl block exoenzyme secretion across the erwinia carotovora outer membrane. | the phytopathogen erwinia carotovora subspecies carotovora secretes pectinases and cellulase via the general secretory pathway, a process requiring at least 13 proteins encoded by the out gene cluster. by exploiting delta::tn5, a generalised transducing phage (psi kp) and localised mutagenesis of the out gene cluster, we have produced a histidine auxotroph and 19 new secretory mutants, including two (hjn1003 and hjn1004) which were conditional (temperature sensitive) for secretion. all of the mu ... | 1998 | 9711844 |
| erwinia carotovora has two kdgr-like proteins belonging to the icir family of transcriptional regulators: identification and characterization of the rexz activator and the kdgr repressor of pathogenesis. | a novel erwinia carotovora subsp. carotovora mutant designated rexz, (regulator of exoenzymes) showed reduced production of the degradative exoenzymes. the rexz gene product shows similarity of the kdgr regulatory protein from erwinia chrysanthemi, described as the major repressor of the pectin catabolism pathway genes in the latter species. in vitro dna-protein interaction experiments demonstrated that the synthesis of the rexz protein is controlled by the camp-crp (camp-receptor protein) compl ... | 1999 | 10439393 |
| prognostic significance of early response to a single dose of asparaginase in childhood acute lymphoblastic leukemia. | the in vitro and in vivo efficacy of a single dose of asparaginase in children with newly diagnosed acute lymphoblastic leukemia and the correlation between in vitro and in vivo antileukemic response and long-term outcome were prospectively evaluated. | 1999 | 10029805 |
| crystallization and preliminary x-ray analysis of a member of a new family of pectate lyases, peil from erwinia chrysanthemi. | peil, a pectate lyase (e.c. 4.2.2.9) from e. chrysanthemi 3937 that is not homologous to the lyases with known structures, has been purified and crystallized by the hanging-drop method using a variety of organic solvents as precipitant. elongated lathes grown from poly(ethylene glycol) plus isopropanol belong to the space group p212121 with cell dimensions a = 55.5, b = 58.2, c = 16.4 a with a single molecule in the asymmetric unit. although complete data sets have been collected to 2.3 a resolu ... | 1998 | 9761915 |
| erwinia carotovora dsba mutants: evidence for a periplasmic-stress signal transduction system affecting transcription of genes encoding secreted proteins. | the dsba genes, which encode major periplasmic disulfide-bond-forming proteins, were isolated from erwinia carotovora subsp. carotovora (ecc) and erwinia carotovora subsp. atroseptica (eca), and the dsbc gene, encoding another periplasmic disulfide oxidoreductase was isolated from ecc. all three genes were sequenced and mutants deficient in these genes were created by marker exchange mutagenesis. the ecc mutants were severely affected in activity and secretion of pectate lyase, probably due to t ... | 1999 | 10463161 |
| isolation of an extracellular protease gene of erwinia carotovora subsp. carotovora strain scc3193 by transposon mutagenesis and the role of protease in phytopathogenicity. | using mini-tn5cmr::gusa, a transposon that allows transcriptional fusions to a promoterless beta-glucuronidase gene, a mutant of erwinia carotovora subsp. carotovora scc3193 deficient in extracellular protease production and soft-rot pathogenicity in plants was isolated. the mutant, designated scc6004, produced normal levels of pectate lyase, polygalacturonase and cellulase. the region of the transposon insertion was partially sequenced to permit the design of specific oligonucleotide primers to ... | 1999 | 10463162 |
| rsmc of the soft-rotting bacterium erwinia carotovora subsp. carotovora negatively controls extracellular enzyme and harpin(ecc) production and virulence by modulating levels of regulatory rna (rsmb) and rna-binding protein (rsma). | previous studies have shown that the production of extracellular enzymes (pectate lyase [pel], polygalacturonase [peh], cellulase [cel], and protease [prt]) and harpin(ecc) (the elicitor of hypersensitive reaction) in erwinia carotovora subsp. carotovora is regulated by rsma, an rna-binding protein, and rsmb, a regulatory rna (rsm stands for regulator of secondary metabolites) (y. liu et al., mol. microbiol. 29:219-234, 1998). we have cloned and characterized a novel regulatory gene, rsmc, that ... | 1999 | 10498717 |
| the response regulator expm is essential for the virulence of erwinia carotovora subsp. carotovora and acts negatively on the sigma factor rpos (sigma s). | the main virulence factors of erwinia carotovora subsp. carotovora, the secreted, extracellular cell-wall-degrading enzymes, are controlled by several regulatory mechanisms. we have isolated transposon mutants with reduced virulence on tobacco. one of these mutants, with a mutation in a gene designated expm, was characterized in this study. this mutant produces slightly reduced amounts of extracellular enzymes in vitro and the secretion of the enzymes is also affected. the expm wild-type allele ... | 1999 | 10478478 |
| oligogalacturonide-mediated induction of a gene involved in jasmonic acid synthesis in response to the cell-wall-degrading enzymes of the plant pathogen erwinia carotovora. | identification of arabidopsis thaliana genes responsive to plant cell-wall-degrading enzymes of erwinia carotovora subsp. carotovora led to the isolation of a cdna clone with high sequence homology to the gene for allene oxide synthase, an enzyme involved in the biosynthesis of jasmonates. expression of the corresponding gene was induced by the extracellular enzymes from this pathogen as well as by treatment with methyl jasmonate and short oligogalacturonides (ogas). this suggests that ogas are ... | 1999 | 10478482 |
| processing of the pectate lyase peli by extracellular proteases of erwinia chrysanthemi 3937. | erwinia chrysanthemi causes soft rot on various plants. the maceration of plant tissues is mainly due to the action of endopectate lyases. the e. chrysanthemi strain 3937 produces eight endopectate lyases (pela, pelb, pelc, peld, pele, peli, pell and pelz) that are secreted by the out pathway. the necrotic response elicited by the wild-type e. chrysanthemi strain on tobacco leaves is due to an extracellular protein secreted by the out machinery. purification of the active factor revealed that it ... | 1998 | 9781882 |
| quorum sensing and the cell-cell communication dependent regulation of gene expression in pathogenic and non-pathogenic bacteria. | although it has been clear for some time that individual bacterial cells employ intra-cellular signalling systems to sense, integrate and process information from their surroundings, their widespread capacity to perceive information from other bacterial cells is only just beginning to be recognised. recent work has established that diverse bacteria exploit a cell-cell communication device to regulate the transcription of multiple target genes. this communication device termed 'quorum sensing', d ... | 1998 | 10081580 |
| integration of the quorum-sensing system in the regulatory networks controlling virulence factor synthesis in erwinia chrysanthemi. | the expi-expr locus drives a quorum-sensing system in the phytopathogenic bacterium, erwinia chrysanthemi. purified expr, an n-acyl homoserine lactone-responsive regulatory protein, binds to the promoter/operator region of the expi and expr genes. dnase i footprinting experiments showed that expr protects the regions between -66 and -40 from the p1 transcription initiation site of expl and between -54 and -18 from the expr transcription initiation site p1. the protected region overlaps the two e ... | 1998 | 9781878 |
| global regulation by the small rna-binding protein csra and the non-coding rna molecule csrb. | csr (carbon storage regulator) is a recently discovered global regulatory system that controls bacterial gene expression post-transcriptionally. its effector is a small rna-binding protein referred to as csra or, in phytopathogenic erwinia species, rsma (repressor of stationary phase metabolites). numerous genes whose expression occurs in the stationary phase of growth are repressed by csra/rsma, and csra activates certain exponential-phase metabolic pathways. glycogen synthesis and catabolism, ... | 1998 | 9781871 |
| characterization of the erwinia chrysanthemi expi-expr locus directing the synthesis of two n-acyl-homoserine lactone signal molecules. | the plant pathogen erwinia chrysanthemi produces three acyl-homoserine lactones (acyl-hsls). one has been identified as n-(3-oxohexanoyl)-homoserine lactone (ohhl), and the two others were supposed to be n (hexanoyl)-homoserine lactone (hhl) and n-(decanoyl)-homoserine lactone (dhl). the genes for a quorum-sensing signal generator (expi) and a response regulator (expr) were cloned. these genes are convergently transcribed and display high similarity to the expi-expr genes of erwinia carotovora. ... | 1998 | 9781877 |
| identification and characterization of the fis operon in enteric bacteria. | the small dna binding protein fis is involved in several different biological processes in escherichia coli. it has been shown to stimulate dna inversion reactions mediated by the hin family of recombinases, stimulate integration and excision of phage lambda genome, regulate the transcription of several different genes including those of stable rna operons, and regulate the initiation of dna replication at oric. fis has also been isolated from salmonella typhimurium, and the genomic sequence of ... | 1998 | 9811652 |
| crystallization and preliminary crystallographic analysis of the endo-polygalacturonase from erwinia carotovora ssp. carotovora. | crystals of endo-polygalacturonase from erwinia carotovora ssp. carotovora have been grown from polyethylene glycol 6000 by the hanging-drop method. polygalacturonase is important in the virulence of this plant pathogen. the protein crystallizes in space group c2 with unit-cell parameters a = 81.3, b = 53.0, c = 103.1 a, beta = 112.6 degrees and with a single molecule in the asymmetric unit. the crystals diffract to 1.9 a. | 1999 | 10089438 |
| the pir gene of erwinia chrysanthemi ec16 regulates hyperinduction of pectate lyase virulence genes in response to plant signals. | the plant pathogenic bacterium erwinia chrysanthemi secretes pectate lyase proteins that are important virulence factors attacking the cell walls of plant hosts. bacterial production of these enzymes is induced by the substrate polypectate-na (napp) and further stimulated by the presence of plant extracts. the bacterial regulator responsible for induction by plant extracts was identified and purified by using a dna-binding assay with the promoter region of pele that encodes a major pectate lyase ... | 1998 | 9826648 |
| reclassification of non-pigmented erwinia herbicola strains from trees as erwinia billingiae sp. nov. | twenty-two erwinia-like strains, isolated from trees since the late fifties and belonging to a distinct phenotypic group with resemblance to pantoea agglomerans, were further characterized by conventional biochemical tests, the biolog metabolic fingerprinting system and fatty acid analysis. their phylogenetic positions were determined by comparing the 16s rrna gene sequence of a representative strain to available sequences of erwinia, pantoea, pectobacterium and brenneria species. the strains we ... | 1999 | 10319458 |
| role of rpos in virulence and stress tolerance of the plant pathogen erwinia carotovora subsp. carotovora. | the plant-pathogenic bacterium erwinia carotovora subsp. carotovora causes plant disease mainly through a number of extracellular plant-cell-wall-degrading enzymes. in this study, the ability of an rpos mutant of the er. carotovora subsp. carotovora strain scc3193 to infect plants and withstand environmental stress was characterized. this mutant was found to be sensitive to osmotic and oxidative stresses in vitro and to be deficient in glycogen accumulation. the production of extracellular enzym ... | 1999 | 10627052 |
| 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 |
| the pect repressor coregulates synthesis of exopolysaccharides and virulence factors in erwinia chrysanthemi. | erwinia chrysanthemi 3937 synthesizes an exopolysaccharide (eps) composed of rhamnose, galactose, and galacturonic acid. fourteen transcriptional fusions in genes required for eps synthesis, named eps, were obtained by tn5-b21 mutagenesis. eleven of them are clustered on the chromosome and are repressed by pect, a regulator of pectate lyase synthesis. in addition, expression of these fusions is repressed by the catabolite regulatory protein, crp, and induced in low osmolarity medium. the three o ... | 1999 | 9885192 |
| the exopolygalacturonate lyase pelw and the oligogalacturonate lyase ogl, two cytoplasmic enzymes of pectin catabolism in erwinia chrysanthemi 3937. | erwinia chrysanthemi 3937 secretes into the external medium several pectinolytic enzymes, among which are eight isoenzymes of the endo-cleaving pectate lyases: pela, pelb, pelc, peld, and pele (family 1); peli (family 4); pell (family 3); and pelz (family 5). in addition, one exo-cleaving pectate lyase, pelx (family 3), has been found in the periplasm of e. chrysanthemi. the e. chrysanthemi 3937 gene kdgc has been shown to exhibit a high degree of similarity to the genes pely of yersinia pseudot ... | 1999 | 10383957 |
| assembly of the type ii secretion machinery of erwinia chrysanthemi: direct interaction and associated conformational change between oute, the putative atp-binding component and the membrane protein outl. | erwinia chrysanthemi secretes, by the type ii secretory pathway, a large number of enzymes, including cellulases and pectinases. this process requires the products of the out genes, which are widely conserved in gram-negative bacteria. the out proteins are thought to form a membrane-associated multiprotein complex. here, we investigated interaction between oute, the putative atp binding component, and outl, an inner membrane protein. we showed, by limited proteolysis, genetic suppression and the ... | 1999 | 10356336 |
| saccharomyces cerevisiae cells harboring the gene encoding sarcotoxin ia secrete a peptide that is toxic to plant pathogenic bacteria. | sarcotoxin ia is a cecropin-type antibacterial protein produced by the flesh fly, sarcophaga peregrina. similar to other bactericidal small proteins produced by insects, sarcotoxin ia is released into the hemolymph of larvae and nymphs upon mechanical injury or bacterial infection. the gene (sarco) that encodes this toxin was introduced into saccharomyces cerevisiae yeast cells and was expressed under a constitutive yeast promoter. the transformed yeast cells were grown in a liquid medium, and a ... | 1999 | 10336869 |
| rpos (sigma-s) controls expression of rsma, a global regulator of secondary metabolites, harpin, and extracellular proteins in erwinia carotovora. | rpos (sigma-s or sigma-38) controls a large array of genes that are expressed during stationary phase and under various stress conditions in escherichia coli and other bacteria. we document here that plant pathogenic and epiphytic erwinia species, such as e. amylovora; e. carotovora subsp. atroseptica, betavasculorum, and carotovora; e. chrysanthemi; e. herbicola; e. rhapontici; and e. stewartii, possess rpos genes and produce the alternate sigma factor. we show that rpos transcription in e. car ... | 1998 | 9658007 |
| the minimal gene set member msra, encoding peptide methionine sulfoxide reductase, is a virulence determinant of the plant pathogen erwinia chrysanthemi. | peptide methionine sulfoxide reductase (msra), which repairs oxidized proteins, is present in most living organisms, and the cognate structural gene belongs to the so-called minimum gene set [mushegian, a. r. & koonin, e. v., (1996) proc. natl. acad. sci. usa 93, 10268-10273]. in this work, we report that msra is required for full virulence of the plant pathogen erwinia chrysanthemi. the following differences were observed between the wild-type and a msra- mutant: (i) the msra- mutant was more s ... | 1999 | 9927663 |
| functional analysis of the carbohydrate-binding domains of erwinia chrysanthemi cel5 (endoglucanase z) and an escherichia coli putative chitinase. | the cel5 cellulase (formerly known as endoglucanase z) from erwinia chrysanthemi is a multidomain enzyme consisting of a catalytic domain, a linker region, and a cellulose binding domain (cbd). a three-dimensional structure of the cbd(cel5) has previously been obtained by nuclear magnetic resonance. in order to define the role of individual residues in cellulose binding, site-directed mutagenesis was performed. the role of three aromatic residues (trp18, trp43, and tyr44) in cellulose binding wa ... | 1999 | 10419961 |
| interacting signal pathways control defense gene expression in arabidopsis in response to cell wall-degrading enzymes from erwinia carotovora. | we have characterized the role of salicylic acid (sa)-independent defense signaling in arabidopsis thaliana in response to the plant pathogen erwinia carotovora subsp. carotovora. use of pathway-specific target genes as well as signal mutants allowed us to elucidate the role and interactions of ethylene, jasmonic acid (ja), and sa signal pathways in this response. gene expression studies suggest a central role for both ethylene and ja pathways in the regulation of defense gene expression trigger ... | 2000 | 10755306 |
| a two-component regulatory system, pehr-pehs, controls endopolygalacturonase production and virulence in the plant pathogen erwinia carotovora subsp. carotovora. | genes coding for the main virulence determinants of the plant pathogen erwinia carotovora subsp. carotovora, the plant cell wall-degrading enzymes, are under the coordinate control of global regulator systems including both positive and negative factors. in addition to this global control, some virulence determinants are subject to specific regulation. we have previously shown that mutations in the pehr locus result in reduced virulence and impaired production of one of these enzymes, an endopol ... | 2000 | 10755308 |
| extracellular polysaccharide of erwinia chrysanthemi cu643. | erwinia chrysanthemi are gram-negative bacterial phytopathogens causing soft rots in a number of plants. the structure of the extracellular polysaccharide (eps) produced by e. chrysanthemi strain cu643, pathogenic to philodendron, has been determined using a combination of chemical and physical techniques including methylation analysis, high- and low-pressure gel-filtration and anion-exchange chromatography, high-ph anion-exchange chromatography, partial acid hydrolysis, mass spectrometry, and 1 ... | 1999 | 10420593 |
| regulation of peld and pele, encoding major alkaline pectate lyases in erwinia chrysanthemi: involvement of the main transcriptional factors. | the main virulence factors of the phytopathogenic bacterium erwinia chrysanthemi are pectinases which attack pectin, the major constituent of the plant cell wall. of these enzymes, the alkaline isoenzyme named peld in strain 3937 and pele in strain ec16 has been described as being particularly important, based on virulence studies of plants. expression of the peld and pele genes is tightly modulated by various regulators, including the kdgr repressor and the cyclic amp-cyclic amp receptor protei ... | 1999 | 10498706 |
| a simple purification method and morphology and component analyses for carotovoricin er, a phage-tail-like bacteriocin from the plant pathogen erwinia carotovora er. | carotovoricin er has been isolated as a phage-tail-like bacteriocin from the plant pathogen erwinia carotovora er [kamimiya, s. et al., (1977), agric. biol. chem. 41, 911-912]. however, the fine morphology and structural composition of carotovoricin er remained to be studied because a large amount of contracted carotovoricin er were present in the bacteriocin preparations so far obtained. to obtain intact carotovoricin er and its major parts, we developed simple and efficient purification method ... | 1999 | 10500998 |
| isolation and identification of antimicrobial furocoumarins from parsley. | photoactive furocoumarins extracted from four varieties of fresh and freeze-dried parsley leaves inhibited a dna repair-deficient escherichia coli in a photobiological assay. using media-modified assays, the human pathogens e. coli o157:h7 and listeria monocytogenes, the spoilage microorganism erwinia carotovora, and listeria innocua were also inhibited. pseudomonas fragi was not inhibited. minimum concentrations of forest green parsley powder in agar which showed inhibition ranged from 0.12% to ... | 1997 | 10465045 |
| quorum sensing in the plant pathogen erwinia carotovora subsp. carotovora: the role of expr(ecc). | the production of the main virulence determinants of the plant pathogen erwinia carotovora subsp. carotovora, the extracellular cell wall-degrading enzymes, is partly controlled by the diffusible signal molecule n-(3-oxohexanoyl)-l-homoserine lactone (ohhl). ohhl is synthesized by the product of the expi/cari gene. linked to expi we found a gene encoding a putative transcriptional regulator of the luxr-family. this gene, expr(ecc), is transcribed convergently to the expi gene and the two open re ... | 2000 | 10755301 |
| evidence against a direct antimicrobial role of h2o2 in the infection of plants by erwinia chrysanthemi. | we have investigated the role of bacterial resistance to oxidative stress in pathogenesis. the oxyr gene from the pathogenic bacterium erwinia chrysanthemi has been characterized. it is closely related to that found in escherichia coli (88% overall amino acid identity). an e. chrysanthemi oxyr mutant strain was constructed by marker exchange. after induction with a sublethal dose of h2o2, this mutant was more sensitive to h2o2 and showed reduced levels of catalase and glutathione reductase activ ... | 2000 | 10755305 |
| reciprocal secretion of proteins by the bacterial type iii machines of plant and animal pathogens suggests universal recognition of mrna targeting signals. | bacterial pathogens of both animals and plants use type iii secretion machines to inject virulence proteins into host cells. although many components of the secretion machinery are conserved among different bacterial species, the substrates for their type iii pathways are not. the yersinia type iii machinery recognizes some secretion substrates via a signal that is encoded within the first 15 codons of yop mrna. these signals can be altered by frameshift mutations without affecting secretion of ... | 1999 | 10536009 |
| plants and microorganisms-listening in on the conversation. | | 1999 | 10504693 |
| characterization of the exopolygalacturonate lyase pelx of erwinia chrysanthemi 3937. | erwinia chrysanthemi 3937 secretes several pectinolytic enzymes, among which eight isoenzymes of pectate lyases with an endo-cleaving mode (pela, pelb, pelc, peld, pele, peli, pell, and pelz) have been identified. two exo-cleaving enzymes, the exopolygalacturonate lyase, pelx, and an exo-poly-alpha-d-galacturonosidase, pehx, have been previously identified in other e. chrysanthemi strains. using a genomic bank of a 3937 mutant with the major pel genes deleted, we cloned a pectinase gene identifi ... | 1999 | 10049400 |
| plants genetically modified to produce n-acylhomoserine lactones communicate with bacteria. | n-acylhomoserine lactones (ahls) play a critical role in plant/microbe interactions. the ahl, n-(3-oxohexanoyl)-l-homoserine lactone (ohhl), induces exoenzymes that degrade the plant cell wall by the pathogenic bacterium erwinia carotovora. conversely, the antifungal activity of the biocontrol bacterium pseudomonas aureofaciens 30-84 is due (at least in part) to phenazine antibiotics whose synthesis is regulated by n-hexanoylhomoserine lactone (hhl). targeting the product of an ahl synthase gene ... | 1999 | 10504705 |
| characterization of sota and sotb, two erwinia chrysanthemi proteins which modify isopropyl-beta-d-thiogalactopyranoside and lactose induction of the escherichia coli lac promoter. | the expression, in escherichia coli, of variants of the erwinia chrysanthemi secretion genes outb and outs under the ptac promoter is toxic to the cells. during attempts to clone e. chrysanthemi genes able to suppress this toxicity, i identified two genes, sota and sotb, whose products are able to reduce the isopropyl-beta-d-thiogalactopyranoside (iptg) induction of the e. coli lac promoter. sota and sotb belong to two different families of the major facilitator superfamily. sota is a member of ... | 2000 | 10671456 |
| 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 |
| n-acyl homoserine lactone binding to the carr receptor determines quorum-sensing specificity in erwinia. | quorum sensing via an n-acyl homoserine lactone (hsl) pheromone controls the biosynthesis of a carbapenem antibiotic in erwinia carotovora. transcription of the carbapenem biosynthetic genes is dependent on the luxr-type activator protein, carr. equilibrium binding of a range of hsl molecules, which are thought to activate carr to bind to its dna target sequence, was examined using fluorescence quenching, dna bandshift analysis, limited proteolysis and reporter gene assays. carr bound the most p ... | 2000 | 10675332 |
| analysis of three clustered polygalacturonase genes in erwinia chrysanthemi 3937 revealed an anti-repressor function for the pecs regulator. | erwinia chrysanthemi 3937 secretes an arsenal of pectinolytic enzymes including several pectate lyases encoded by the pel genes. we characterized a novel cluster of pectinolytic genes consisting of the three adjacent genes pehv, pehw and pehx, whose products have polygalacturonase activity. the high similarity between the three genes suggests that they result from duplication of an ancestral gene. the transcription of pehv, pehw and pehx is dependent on several environmental conditions. they are ... | 1999 | 10564505 |
| the phytopathogenic bacteria erwinia carotovora infects drosophila and activates an immune response. | although drosophila possesses potent immune responses, little is known about the microbial pathogens that infect drosophila. we have identified members of the bacterial genus erwinia that induce the systemic expression of genes encoding antimicrobial peptides in drosophila larvae after ingestion. these erwinia strains are phytopathogens and use flies as vectors; our data suggest that these strains have also evolved mechanisms for exploiting their insect vectors as hosts. erwinia infections induc ... | 2000 | 10725405 |
| extracellular polysaccharide of erwinia chrysanthemi a350 and ribotyping of erwinia chrysanthemi spp. | erwinia chrysanthemi spp. are gram-negative bacterial phytopathogens causing soft rots in a number of plants. the structure of the extracellular polysaccharide (eps) produced by the e. chrysanthemi strain a350, which is a lacz- mutant of the wild type strain 3937, pathogenic to saintpaulia, has been determined using a combination of chemical and physical techniques including methylation analysis, low-pressure gel-filtration and anion-exchange chromatography, high-ph anion-exchange chromatography ... | 2000 | 10744334 |
| self-regulation of pir, a regulatory protein responsible for hyperinduction of pectate lyase in erwinia chrysanthemi ec16. | previously, we have cloned and characterized the pir (plant inducible regulator) gene, which is responsible for hyperinduction of the synthesis of an isozyme of pectate lyase (ple) in erwinia chrysanthemi ec16 in the presence of potato extract and sodium polypectate (napp). the pir protein purified from escherichia coli overexpressing pir is able to bind to the promoter region of pir as a dimer. self-regulation of pir by its own translational product (pir) was suggested from the findings that pi ... | 1999 | 10226371 |
| the phylogenetic position of serratia, buttiauxella and some other genera of the family enterobacteriaceae. | the phylogenetic relationships of the type strains of 38 species from 15 genera of the family enterobacteriaceae were investigated by comparative 16s rdna analysis. several sequences of strains from the genera citrobacter, erwinia, pantoea, proteus, rahnella and serratia, analysed in this study, have been analysed previously. however, as the sequences of this study differ slightly from the published ones, they were included in the analysis. of the 23 enterobacterial genera included in an overvie ... | 1999 | 10555323 |
| [the effect of the substance exin on development of microbial infections and isolation of ethylene in plants]. | effects of exin on infection of tomato, potato, and cabbage plants with pseudomonas solanacearum and erwinia carotovora and a fungus sclerotium rolfsii were studied. the treatment of infected plants with exin caused no significant effect on the development of the disease. treatment with streptomycin as a standard for comparison completely inhibited the growth of these microorganisms. pretreatment with exin one to eight days before infecting inhibited the development of diseases. the numbers of t ... | 2000 | 10780015 |
| regulation of hexuronate utilization in bacillus subtilis. | we have identified a locus essential for galacturonate utilization in bacillus subtilis. genes homologous to escherichia coli and erwinia chrysanthemi glucuronate and galacturonate metabolic genes were found in a cluster consisting of 10 open reading frames (orfs) in the b. subtilis chromosome. a mutant of b. subtilis containing a replacement of the second and third orfs was unable to grow with galacturonate as its primary carbon source. galacturonate induced expression from a sigmaa-dependent p ... | 1999 | 9882655 |
| overproduction of the secretin outd suppresses the secretion defect of an erwinia chrysanthemi outb mutant. | outb is a component of the erwinia chrysanthemi out secretion machinery. homologues of outb have been described in two other bacteria, klebsiella oxytoca and aeromonas hydrophila, but their requirement in the secretion process seems to be different. study of outb topology with the blam topology probe suggests that it is an inner-membrane protein with a large periplasmic domain. however, fractionation experiments indicate that it could be associated with the outer membrane through its c-terminal ... | 2000 | 10746767 |
| molecular genetics of carbapenem antibiotic biosynthesis. | carbapenems are potent beta-lactam antibiotics with a broad spectrum of activity against both gram positive and gram negative bacteria. as naturally produced metabolites, they have been isolated from species of streptomyces, erwinia and serratia. the latter two members of the enterobacteriaceae have proved to be genetically amenable and a growing body of research on these organisms now exists concerning the genes responsible for carbapenem biosynthesis and the regulatory mechanisms controlling t ... | 1999 | 10422586 |
| biosynthesis of carbapenem antibiotic and prodigiosin pigment in serratia is under quorum sensing control. | serratia sp. atcc 39006 produces the carbapenem antibiotic, carbapen-2-em-3-carboxylic acid and the red pigment, prodigiosin. we have previously reported the characterization of a gene, carr, controlling production of carbapenem in this strain. we now describe further characterization of the carr locus to locate the genes encoding carbapenem biosynthetic and resistance functions. a novel family of diverse proteins showing sequence similarity to the c-terminal domain of carf (required for carbape ... | 2000 | 10844645 |
| fermentations of pectin-rich biomass with recombinant bacteria to produce fuel ethanol. | pectin-rich residues from sugar beet processing contain significant carbohydrates and insignificant amounts of lignin. beet pulp was evaluated for conversion to ethanol using recombinant bacteria as biocatalysts. hydrolysis of pectin-rich residues followed by ethanolic fermentations by yeasts has not been productive because galacturonic acid and arabinose are not fermentable to ethanol by these organisms. the three recombinant bacteria evaluated in this study, escherichia coli strain ko11, klebs ... | 2000 | 10849785 |
| a competitive pcr-based method for the detection and quantification of erwinia carotovora subsp. atroseptica on potato tubers. | a pcr-based method was developed for the simultaneous detection and quantification of the potato pathogen erwinia carotovora subsp. atroseptica (eca) on potato tubers. the method incorporates a competitor pcr template cloned into escherichia coli in vector pgem-t (e. coli 4r l/l). predetermined numbers of e. coli 4r were added to potato peel extract, either pre-inoculated with eca or from naturally contaminated tubers, and eca numbers estimated by comparing the ratio of products generated from e ... | 2000 | 10792657 |
| cloning and sequencing of pel gene responsible for cmcase activity from erwinia chrysanthemi py35. | the phytopathogenic bacterium erwinia chrysanthemi secretes multiple isozymes of plant cell wall disrupting enzymes such as pectate lyase and endoglucanase. we cloned genomic dna from erwinia chrysanthemi py35. one of the e. coli xl1-blue clones contained a 5.1-kb bamhi fragment and hydrolyzed carboxymethyl cellulose and polygalacturonic acid. by subsequent subcloning, we obtained a 2.9-kb fragment (ppy100) that contained the pel gene responsible for cmcase and pectate lyase activities. the pel ... | 2000 | 10879460 |
| cloning and sequencing of cel5z gene from erwinia chrysanthemi py35. | the phytopathogenic bacterium erwinia chrysanthemi (ech) secretes multiple isozymes of plant cell wall disrupting enzymes such as pectate lyase and endoglucanases. we cloned genomic dna from ech py35 digested with sau3ai and ligated into pbluescript ii sk+. one of the e. coli xl1-blue clones had the ability to hydrolyze carboxymethyl cellulose and polygalacturonic acid. by subsequent subcloning from this 2.9 kb fragment, we obtained a 2.0 kb (ppy401), designated cel5z, which had the activity of ... | 2000 | 10901164 |
| a new high-alkaline and high-molecular-weight pectate lyase from a bacillus isolate: enzymatic properties and cloning of the gene for the enzyme. | a pectate lyase (pel; pectate transeliminase: ec4.2.2.2.), designated pel-15h, was found in an alkaline culture of bacillus sp. strain ksm-p15 and purified to homogeneity by sequential column chromatographies. the molecular weight of the enzyme determined by sds-polyacrylamide gel electrophoresis was approximately 70,000 and the pi was around ph 4.6. pel-15h randomly trans-eliminated polygalacturonate in the presence of ca2+ ions, and the maximum activity was observed at ph 11.5 and at 55 degree ... | 2000 | 10923781 |
| linear beta-1,3 glucans are elicitors of defense responses in tobacco. | laminarin, a linear beta-1,3 glucan (mean degree of polymerization of 33) was extracted and purified from the brown alga laminaria digitata. its elicitor activity on tobacco (nicotiana tabacum) was compared to that of oligogalacturonides with a mean degree of polymerization of 10. the two oligosaccharides were perceived by suspension-cultured cells as distinct chemical stimuli but triggered a similar and broad spectrum of defense responses. a dose of 200 microg ml(-1) laminarin or oligogalacturo ... | 2000 | 11080280 |
| degree of acetylation of heteropolysaccharides. | the acetyl groups in polysaccharides and glycoproteins have been determined using 4 n hcl at 120 degrees c for acid hydrolysis. acetic acid and hexosamine were determined by high-performance cation-exchange chromatography with uv detection and high-performance anion-exchange chromatography with pulsed amperomeric detection, respectively. the method compares well with other procedures and shows an additional advantage of being able to analyze for hexosamine in the same hydrolyzate, thus permittin ... | 2000 | 10782297 |
| overproduction in escherichia coli of the pectin methylesterase a from erwinia chrysanthemi 3937: one-step purification, biochemical characterization, and production of polyclonal antibodies. | pectin methylesterase a (ec 3.1.1.11), one of the pathogenicity factors of erwinia chrysanthemi strain 3937, was purified to homogeneity using one-step chromatography on cross-linked pectate. the purified protein showed maximum activity at ph 8-9, 50 degrees c, 50-100 mm monovalent cations or 5-10 mm divalent cations, and on a 50% esterified pectin. a particular effect of ca2+ and zn2+ on pmea activity, due to the formation of a pectin gel, was observed. a km value of 0.03% and 0.051% was determ ... | 2000 | 10872083 |
| achromobactin, a new citrate siderophore of erwinia chrysanthemi. | the structure of a citrate siderophore named achromobactin isolated from the culture medium of erwinia chrysanthemi was elucidated by spectroscopic methods and chemical degradation. | 2000 | 10928541 |
| genetic dissection of the outer membrane secretin puld: are there distinct domains for multimerization and secretion specificity? | linker and deletion mutagenesis and gene fusions were used to probe the possible domain structure of the dodecameric outer membrane secretin puld from the pullulanase secretion pathway of klebsiella oxytoca. insertions of 24 amino acids close to or within strongly predicted and highly conserved amphipathic beta strands in the c-terminal half of the polypeptide (the beta domain) abolished sodium dodecyl sulfate (sds)-resistant multimer formation that is characteristic of this protein, whereas ins ... | 1999 | 10572123 |
| evaluation of phenotypic and molecular typing techniques for determining diversity in erwinia carotovora subspp. atroseptica. | a number of phenotypic and molecular fingerprinting techniques, including physiological profiling (biolog), restriction fragment length polymorphism (rflp), enterobacterial repetitive intergenic consensus (eric) and a phage typing system, were evaluated for their ability to differentiate between 60 strains of erwinia carotovora ssp. atroseptica (eca) from eight west european countries. these techniques were compared with other fingerprinting techniques, random amplified polymorphic dna (rapd) an ... | 1999 | 10594720 |
| 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 |
| aiia, an enzyme that inactivates the acylhomoserine lactone quorum-sensing signal and attenuates the virulence of erwinia carotovora. | n-acylhomoserine lactones, known as autoinducers (ais), are widely conserved signal molecules present in quorum-sensing systems of many gram-negative bacteria. ais are involved in the regulation of diverse biological functions, including expression of pathogenic genes in the plant pathogens pseudomonas solanacearum, several erwinia species, and the human pathogen pseudomonas aeruginosa. a bacterial isolate, bacillus sp. 240b1, is capable of enzymatic inactivation of ais. the gene (aiia) for ai i ... | 2000 | 10716724 |
| modes of action of five different endopectate lyases from erwinia chrysanthemi 3937. | five endopectate lyases from the phytopathogenic bacterium erwinia chrysanthemi, pela, pelb, peld, peli, and pell, were analyzed with respect to their modes of action on polymeric and oligomeric substrates (degree of polymerization, 2 to 8). on polygalacturonate, pelb showed higher reaction rates than peld, peli, and pela, whereas the reaction rates for pell were extremely low. the product progression during polygalacturonate cleavage showed a typical depolymerization profile for each enzyme and ... | 1999 | 10368144 |
| structure of a plant cell wall fragment complexed to pectate lyase c. | the three-dimensional structure of a complex between the pectate lyase c (pelc) r218k mutant and a plant cell wall fragment has been determined by x-ray diffraction techniques to a resolution of 2.2 a and refined to a crystallographic r factor of 18.6%. the oligosaccharide substrate, alpha-d-galpa-([1-->4]-alpha-d-galpa)3-(1-->4)-d-galpa , is composed of five galacturonopyranose units (d-galpa) linked by alpha-(1-->4) glycosidic bonds. pelc is secreted by the plant pathogen erwinia chrysanthemi ... | 1999 | 10368179 |
| 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 |
| 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 |
| 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 |
| characterization of erwinia chrysanthemi py35 cel and pel gene existing in tandem and rapid identification of their gene products. | genomic dna of the phytopathogenic erwinia chrysanthemi py35 was partially digested with sau3ai, ligated into the bamhi site of pbluescript ii sk+, and introduced into e. coli. one clone that was able to hydrolyse carboxymethylcellulose and polygalacturonic acid was selected. a 2.9 kb fragment containing the pell1 gene (ppy300) and cel5z gene (ppy401) in tandem was subcloned and sequenced. the pell1 and cel5z genes had open reading frames of 1,278 bp and 1,281 bp encoding 425 and 426 amino acid ... | 2000 | 10679220 |
| gene integration and expression and extracellular secretion of erwinia chrysanthemi endoglucanase cely (cely) and celz (celz) in ethanologenic klebsiella oxytoca p2. | the development of methods to reduce costs associated with the solubilization of cellulose is essential for the utilization of lignocellulose as a renewable feedstock for fuels and chemicals. one promising approach is the genetic engineering of ethanol-producing microorganisms that also produce cellulase enzymes during fermentation. by starting with an ethanologenic derivative (strain p2) of klebsiella oxytoca m5a1 with the native ability to metabolize cellobiose, the need for supplemental beta- ... | 2001 | 11133422 |
| 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 |
| 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 |