Publications

erwinia chrysanthemi and pseudomonas syringae: plant pathogens trafficking in extracellular virulence proteins.		1994	7859513
negligible hemostatic toxicity of intermediate-dose erwinase in adult patients with acute lymphoblastic leukemia: preliminary data.	the hemostatic toxicity of low dose l-asparaginase from erwinia carotovora (erwinase) has been reported to be negligible in adult patients with acute lymphoblastic leukemia (all); conversely, no consistent data have been obtained when erwinase is administered at intermediate doses. we report preliminary clinical and laboratory hemostatic data from 10 adult patients with all treated during induction phase with intermediate doses of erwinase (20,000 iu/m2s.c. every other day, for a total of six ad ...	1994	7896215
pcr and restriction fragment length polymorphism of a pel gene as a tool to identify erwinia carotovora in relation to potato diseases.	using a sequenced pectate lyase-encoding gene (pel gene), we developed a pcr test for erwinia carotovora. a set of primers allowed the amplification of a 434-bp fragment in e. carotovora strains. among the 89 e. carotovora strains tested, only the erwinia carotovora subsp. betavasculorum strains were not detected. a restriction fragment length polymorphism (rflp) study was undertaken on the amplified fragment with seven endonucleases. the sau3ai digestion pattern specifically identified the erwi ...	1994	7912502
nucleotide sequence, organization and expression of rdga and rdgb genes that regulate pectin lyase production in the plant pathogenic bacterium erwinia carotovora subsp. carotovora in response to dna-damaging agents.	in most soft-rotting erwinia spp., including e. carotovora subsp. carotovora strain 71 (ecc71), production of the plant cell wall degrading enzyme pectin lyase (pnl) is activated by dna-damaging agents such as mitomycin c (mc). induction of pnl production in ecc71 requires a functional reca gene and the rdg locus. dna sequencing and rna analyses revealed that the rdg locus contains two regulatory genes, rdga and rdgb, in separate transcriptional units. there is high homology between rdga and rep ...	1994	7715460
extracellular polysaccharide of erwinia chrysanthemi ech6.	many strains of erwinia chrysanthemi, which are gram-negative bacterial phytopathogens, produce copious amounts of extracellular polysaccharides. the extracellular polysaccharide from e. chrysanthemi pv. zeae strain sr 260, a phytopathogen of corn, is a branched-chain glucomannorhamnan of proven structure (gray et al., carbohydr. res. 1993, 245, 271-287). the extracellular polysaccharide from e. chrysanthemi ech6 is different, containing no rhamnose or mannose. it is composed of l-fucose, d-gala ...	1994	7727344
[expression of pectate lyase genes of erwinia carotovora subsp. carotovora 17a and erwinia carotovora subsp. atroseptica 36a in erwinia carotovor substp. atroseptica 36a cells].	e.atroseptica 36a cells were transformed by the recombinant plasmids p27-1 and pea364 (derivatives of the vector plasmid puc19) containing pectate lyase genes of e.carotovora 17a and e.atroseptica 36a, respectively. the synthesis of pectate lyases determined by the cloned genes of bacteria of both subspecies, as well as the synthesis of the native enzymes, were induced by sodium poly pectate. increase of the dose of pectate lyase genes did not result in alteration of pectate lyase secretion by e ...	1994	7739592
identification of the integration host factor genes of erwinia chrysanthemi 3937.	two erwinia chrysanthemi homologues of the hima and himd genes of escherichia coli which encode the integration host factor (ihf) were cloned, sequenced and compared to their homolog in other enterobacteria (embl accession nos x74749 and x74750). both genes were inactivated by the insertion of an antibiotic resistance cassette, allowing for the isolation of ihf- mutants of e chrysanthemi.	1994	7748927
crystal structure of a complex between serratia marcescens metallo-protease and an inhibitor from erwinia chrysanthemi.	the crystal structure of the complex between the 50 kda metallo-endoproteinase from serratia marcescens (smp), a member of the metzincin superfamily, and an inhibitor from erwinia chrysanthemi (inh) was solved by molecular replacement using the known structure of smp, and refined at 2.30 a resolution to a crystallographic r-factor of 0.195. the e. chrysanthemi inhibitor folds into a compact eight-stranded antiparallel beta-barrel of simple up-down topology such as is found for members of the ret ...	1995	7752231
characterization of a novel pectate lyase from erwinia carotovora subsp. carotovora.	the pectate lyase (pel, ec 4.2.2.2) isoenzyme profile of erwinia carotovora subsp. carotovora was characterized by isoelectric focusing, and the corresponding genes coding for four different exported pels were cloned. the nucleotide sequence of the pelb gene encoding one of these isoenzymes was determined and was shown to contain 1,040-bp open reading frame coding for a 37,482-da protein with a putative cleavable amino terminal signal peptide. overexpression and selective labeling experiments wi ...	1995	7756691
structure-based multiple alignment of extracellular pectate lyase sequences.	pectate lyases are secreted virulence factors which degrade the pectate component of plant cell walls. the evolutionary-based multiple alignment of extracellular pectate lyases has been corrected using three-dimensional structural information derived from erwinia chyrsanthemi pectate lyases c and e. the new multiple alignment reveals invariant amino acids likely to be involved in two different enzymatic functions.	1995	7756698
small molecule mediated autoinduction of antibiotic biosynthesis in the plant pathogen erwinia carotovora.		1995	7758689
effects of synthetic bombyx mori cecropin b on the growth of plant pathogenic bacteria.		1995	7745285
structure and regulation of the erwinia carotovora subspecies carotovora scc3193 cellulase gene celv1 and the role of cellulase in phytopathogenicity.	the celv1 gene encoding a secreted cellulase (celv1) of erwinia carotovora subsp. carotovora scc3193 was cloned and its nucleotide sequence determined. the gene contains an open reading frame of 1511 bp and codes for an exported protein of 504 amino acids. the predicted amino acid sequence of celv1 was highly similar to that of celv of another e. c. subsp. carotovora strain scr1193 but completely different from the previously characterized cellulase, cels, of the strain scc3193. gene fusions to ...	1995	7715600
cloning and characterization of the bgxa gene from erwinia chrysanthemi d1 which encodes a beta-glucosidase/xylosidase enzyme.	a beta-glucosidase/xylosidase gene from erwinia chrysanthemi strain d1 was cloned and sequenced. this gene, named bgxa, encodes a ca. 71 kda protein product which, following removal of the leader peptide, resulted in a ca. 69 kda mature protein that accumulated in the periplasmic space of e. chrysanthemi strain d1 and escherichia coli cells expressing the cloned gene. the protein exhibited both beta-glucosidase and beta-xylosidase activities but gave no detectable activity on xylan or carboxymet ...	1995	7891660
nucleotide sequence of a pectate lyase structural gene, pel1 of erwinia carotovora subsp. carotovora strain 71 and structural relationship of pel1 with other pel genes of erwinia species.	of the various exoproteins secreted by erwinia carotovora subsp. carotovora strain 71, pel1 is the major pectate lyase species with tissue macerating activity. nucleotide sequencing of a 2.2-kb pel1+ dna segment revealed a 1,122 base pair open reading frame which could encode pre-pel1 of 374 amino acid residues. a signal peptide of 22 amino acid residues is present within the nh2-terminal region of pre-pel1. transcription of pel1 was initiated at the guanine residue 111 base pairs upstream of th ...	1995	7772808
flavohaemoglobin hmpx: a new pathogenicity determinant in erwinia chrysanthemi strain 3937.	unlike wild-type erwinia chrysanthemi strain 3937, which fully macerates inoculated saintpaulia plants, hmpx- mutants produce necrotic lesions or no symptoms. the hmpx gene was sequenced and the corresponding protein sequence analysed. we show that hmpx belongs to a family of flavohaemoproteins (hmp), previously identified in two yeasts and in escherichia coli. comparisons of protein sequences at the secondary structure level by hydrophobic cluster analysis have shown that hmpx possesses two fun ...	1995	7773389
protein secretion by hybrid bacterial abc-transporters: specific functions of the membrane atpase and the membrane fusion protein.	the erwinia chrysanthemi metalloprotease c and the serratia marcescens haem acquisition protein hasa are both secreted from gram-negative bacteria by a signal peptide-independent pathway which requires a c-terminal secretion signal and a specific abc-transporter made up of three proteins: a membrane atpase (the abc-protein), a second inner membrane component belonging to the membrane fusion protein family and an outer membrane polypeptide. hasa and protease c transporters are homologous although ...	1995	7774588
informational suppression to investigate structural functional and evolutionary aspects of the erwinia chrysanthemi cellulase egz.	the cellulase egz produced by the plant pathogen erwinia chrysanthemi belongs to family 5 of the beta-glycohydrolases (also referred to as cellulase family a), which contains over 40 members from gram-negative and gram-positive bacteria and fungi. amber mutations were introduced into 16 codons of the celz gene encoding egz. targeted residues included: (1) two glu, two his and one arg residue, strictly conserved throughout family 5; (2) one arg and one his residue conserved in sub-family 5-2; and ...	1995	7853408
differential effect of dsba and dsbc mutations on extracellular enzyme secretion in erwinia chrysanthemi.	an erwinia chrysanthemi gene able to complement an escherichia coli dsba mutation has been cloned and sequenced. this gene codes for a periplasmic protein with disulphide isomerase activity that has 69% identity and 94% similarity with the e. coli dsba protein. an e. chrysanthemi dsba-uida fusion mutant has been constructed. dsba expression seems to be constitutive. this mutant has multiple phenotypes resulting from the absence of disulphide bond formation in periplasmic and secreted proteins. p ...	1995	7476168
purification and characterization of an extracellular pectate lyase from an amycolata sp.	the extracellular pectate lyase (ec 4.2.2.2) of a nonsporulating amycolata sp. was purified to homogeneity by anion- and cation-exchange chromatographies followed by hydrophobic interaction chromatography. the enzyme cleaved polygalacturonate but not highly esterified pectin in a random endolytic transeliminative mechanism that led to the formation of a wide range of 4,5-unsaturated oligogalacturonates. as shown by high-performance anion-exchange chromatography and pulsed amperometric detection, ...	1995	7486993
characterization of monoclonal antibodies against erwinia carotovora subsp. atroseptica serogroup i: specificity and epitope analysis.	the characteristics of two monoclonal antibodies (mabs), a23/1221.59.44.d.3 (1221) and a23/1239.36.64.e.2 (1239), against erwinia carotovora subsp. atroseptica serogroup i produced in this study were compared with those of two other independently obtained mabs, 4g4 in spain and 4f6 in canada, using different strains as immunogen and different screening procedures. the reaction pattern of mabs 1221 and 1239 determined by indirect elisa on over 200 bacterial strains including five e.c. atroseptica ...	1995	7538107
the effect of hetastarch on the stability of l-asparaginase during freeze-thaw cycling.	l-asparaginase, a therapeutic agent for the treatment of acute lymphoblastic leukemia, was evaluated for its susceptibility to cold denaturation. it was found that the enzyme derived from erwinia chrysanthemi loses its activity when exposed to freeze-thaw cycling. when it was frozen at -40 degrees c and thawed, the enzyme lost 67.3% of its activity; whereas, when frozen in liquid nitrogen (-190 degrees c), it lost almost all of its activity. rheological studies of hetastarch showed that its visc ...	1995	7542144
[mapping chromosomes of erwinia carotovora subsp. atroseptica 3-2].	two hfr-like donor strains of bacteria erwinia carotovora subsp. atroseptica (eca) 3-2 were developed by integration into the chromosome of the conjugative plasmid r471a via homology with transposon tn9. using these and two donor strains created earlier, we constructed the genetic map of a fragment of the chromosome of strain eca 3-2. the location of 14 loci is shown in this map.	1995	7590201
[a circular genetic map of chromosomes from erwinia carotovora subsp. atroseptica 3-2].	a circular genetic map of the bacterium erwinia carotovora subsp. atroseptica 3-2 was constructed on the basis of the r471a plasmid and tn5 and tn9 using hfr-like donors. forty-six genes, including phytopathogenicity genes, were located on the basis of interrupted mating experiment results and analysis of coinheritance of markers on a map of 183 min in length. the similarity and differences of chromosomal genetic maps of erwinia genus bacteria are discussed.	1995	7590213
purification and characterization of the nuclease nucm of erwinia chrysanthemi.	the major periplasmic nuclease of erwinia chrysanthemi strain 3937, nucm, has been purified near to homogeneity by a one step purification procedure, using chromatography on a sulfopropyl column. nucm cleaves randomly single and double-stranded dna and rna. it does not need divalent cations for its action, and is more active in low salt buffers. a serine and a histidine residue could be present in the catalytic site. formation of disulfide bonds is necessary for nucm activity. nucm is probably s ...	1995	7599187
the gene (arok) encoding shikimate kinase i from escherichia coli.	shikimate kinase i (ski), encoded by the arok gene, converts shikimate to shikimate 3-phosphate, an intermediate in the biosynthesis of the aromatic amino acids. this paper provides evidence that the e. coli arok reading frame is in a different place to that reported previously and presents a predicted ski sequence of 173 residues and a molecular mass of 19.5 kda. the translational start point of arok is some 84 bp downstream of the site proposed earlier and the reading frame ends 169 bp beyond ...	1995	7612934
overproduction, purification and characterization of the cellulose-binding domain of the erwinia chrysanthemi secreted endoglucanase egz.	egz is the major endoglucanase secreted by erwinia chrysanthemi. functional characterization indicates that it is made of a catalytic n-terminal domain linked to a c-terminal cellulose-binding domain (cbd) by a ser/thr-rich linker. a chimeric plasmid, in which the cbd-encoding region was fused downstream of the ompa signal sequence, was constructed and introduced into escherichia coli. this allowed for the production of processed and disulfide-bonded cbd, mostly recovered from the culture supern ...	1995	7628464
a rapid one-tube genomic dna extraction process for pcr and rapd analyses.		1995	7630740
use of tn5tac1 to clone a pel gene encoding a highly alkaline, asparagine-rich pectate lyase isozyme from an erwinia chrysanthemi ec16 mutant with deletions affecting the major pectate lyase isozymes.	erwinia chrysanthemi mutant cucpb5047, delta(pela pele) delta(pelb pelc)::28bp delta(pelx) delta 4bp pehx::omega cmr, was constructed, mutated with tn5tac1, and screened for isopropyl-beta-d-thiogalactopyranoside-dependent pectate lyase (pel) production. a kmr saci fragment from the hyperexpressing pel+ mutant cucpb5066 was cloned into escherichia coli and sequenced. the gene identified, pell, encodes a novel, asparagine-rich, highly alkaline enzyme that is similar in primary structure to pelx a ...	1995	7635842
cloning and sequencing of the gyra gene from the plant pathogen erwinia carotovora.	the gyra gene of erwinia carotovora subsp. carotovora has been cloned and sequenced. the deduced protein possessed 86% identity with the escherichia coli gyra protein. e. carotovora gyra was also shown to complement an e. coli gyra43ts mutation.	1995	7642123
inactivation of rsma leads to overproduction of extracellular pectinases, cellulases, and proteases in erwinia carotovora subsp. carotovora in the absence of the starvation/cell density-sensing signal, n-(3-oxohexanoyl)-l-homoserine lactone.	the soft-rotting bacterium, erwinia carotovora subsp. carotovora 71, produces extracellular enzymes such as pectate lyase isozymes (pels), cellulase (cel), polygalacturonase (peh), and protease (prt). while the extracellular levels of these enzymes are extremely low when the bacterium is grown in salts-yeast extract-glycerol (syg) medium, the enzymatic activities are highly induced in syg medium supplemented with celery extract. by transposon (mini-tn5) mutagenesis, we isolated a rsma- mutant, a ...	1995	7646031
characterization of a pathogen-induced potato catalase and its systemic expression upon nematode and bacterial infection.	we have isolated a cdna encoding a catalase (cat2st) by differential screening of a cdna library constructed from potato roots infected with the cyst nematode globodera pallida. expression analysis confirmed the local induction of cat2st and showed that it was highest at the adult stage of the parasite. it also revealed that cat2st was induced in uninfected roots, stems, and leaves of infected plants. localized and systemic induction of cat2st was also observed upon root-knot nematode (meloidogy ...	1995	7655060
identification of a global repressor gene, rsma, of erwinia carotovora subsp. carotovora that controls extracellular enzymes, n-(3-oxohexanoyl)-l-homoserine lactone, and pathogenicity in soft-rotting erwinia spp.	the production of extracellular enzymes such as pectate lyase (pel), polygalacturonase (peh), cellulase (cel), and protease (prt) is activated by the cell density (quorum)-sensing signal, n-(3-oxohexanoyl)-l-homoserine lactone (hsl); plant signals; and aep genes during postexponential growth of erwinia carotovora subsp. carotovora 71. studies with mutants of e. carotovora subsp. carotovora 71 derepressed in exoenzyme production led to the identification of a negative regulator gene, rsma (rsm, r ...	1995	7665490
extracellular polysaccharide of erwinia chrysanthemi.		1995	7697648
carbapenem antibiotic production in erwinia carotovora is regulated by carr, a homologue of the luxr transcriptional activator.	strain gs101 of erwinia carotovora makes the carbapenem antibiotic, 1-carbapen-2-em-3-carboxylic acid. mutants defective in antibiotic production can be assigned to two groups, group 1 and group 2. group 2 mutants are defective in the carl gene encoding a protein responsible for synthesis of the lux autoinducer n-(3-oxohexanoyl)-l-homoserine lactone (ohhl), which is required to induce carbapenem synthesis in strain gs101. in this paper we describe the molecular genetic analysis of the group 1 mu ...	1995	7711893
characterization of the pell gene encoding a novel pectate lyase of erwinia chrysanthemi 3937.	erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pela, pelb, pelc, peld and pele genes. recently, a new set of pectate lyases was identified in e. chrysanthemi mutants deleted of those pel genes. we cloned the pell gene, encoding one of these secondary pectate lyases of e. chrysanthemi 3937, from a genomic bank of a strain deleted of the five major pel genes. the nucleotide sequence of the region containing the pell gene was determined. the pell reading f ...	1995	8577252
erwinia chrysanthemi harpinech: an elicitor of the hypersensitive response that contributes to soft-rot pathogenesis.	mutants of the soft-rot pathogen erwinia chrysanthemi ec16 that are deficient in the production of the pectate lyase isozymes pelabce can elicit the hypersensitive response (hr) in tobacco leaves. the hrpnech gene was identified in a collection of cosmids carrying e. chrysanthemi hrp genes by its hybridization with the erwinia amylovora hrpnea gene. hrpnech appears to be in a monocistronic operon, and it encodes a predicted protein of 340 amino acids that is glycine-rich, lacking in cysteine, an ...	1995	8589405
disease resistance conferred by expression of a gene encoding h2o2-generating glucose oxidase in transgenic potato plants.	plant defense responses to pathogen infection involve the production of active oxygen species, including hydrogen peroxide (h2o2). we obtained transgenic potato plants expressing a fungal gene encoding glucose oxidase, which generates h2o2 when glucose is oxidized. h2o2 levels were elevated in both leaf and tuber tissues of these plants. transgenic potato tubers exhibited strong resistance to a bacterial soft rot disease caused by erwinia carotovora subsp carotovora, and disease resistance was s ...	1995	8589621
differential expression of two siderophore-dependent iron-acquisition pathways in erwinia chrysanthemi 3937: characterization of a novel ferrisiderophore permease of the abc transporter family.	in planta expression of a high-affinity iron-uptake system involving the siderophore chrysobactin in erwinia chrysanthemi 3937 contributes greatly to invasive growth of this pathogen on its natural host, african violets. a previous study reported that global regulation by iron in this strain was mediated at the transcriptional level via the cbr locus which, when inactivated by insertional mutation, prevents the chrysobactin system from being tightly repressed by fecl3. herein, we report the nucl ...	1995	8596459
antibiotics and garlic clove extract--inhibitory agents of cell wall degrading enzymes.	four antibiotics were tested against erwinia causing soft rot of onion (allium cepa var. aggregatum) of which streptomycin sulphate 90% and tetracycline hydrochloride 10% (streptocycline) recorded the maximum inhibition zone of 27.66 mm. in the enzyme studies the maximum inhibition of pectinlyase (pl), polygalacturonase (pg) and protopectinase production was recorded by the same antibiotic. the antibiotics have a significant influence on the production and activity of cell wall degrading enzymes ...	1995	8972140
"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
hemostasis in childhood acute lymphoblastic leukemia: coagulopathy induced by disease and treatment.	thromboembolic events (te) are serious complications of treatment for childhood acute lymphoblastic leukemia (all) that result in significant morbidity and occasionally mortality. these events are strongly associated with the administration of l'asparaginase (asp). there have been many studies reporting te and assessing the coagulopathy associated with treatment. the intention of these studies was to determine a potential mechanism for thrombosis. this article reviews the current literature in t ...	1995	8747702
the extreme c-terminus is required for secretion of both the native polygalacturonase (peha) and peha-bla hybrid proteins in erwinia carotovora subsp. carotovora.	a set of gene fusions was constructed between the peha gene encoding the secreted endopolygalacturonase (peha) and the bla gene coding for a normally periplasmic beta-lactamase (bla). the resulting hybrid proteins were specifically and actively routed out of the cells via the out-terminal branch of the general secretory pathway (gsp) in erwinia carotovora subsp. carotovora (ecc), provided that no more than the last two amino acids (aa) of the peha domain were excluded from the fusion. however, b ...	1995	8559064
polymerase chain reaction for verification of fluorescent colonies of erwinia chrysanthemi and pseudomonas putida wcs358 in immunofluorescence colony staining.	the potential of polymerase chain reaction (pcr) for verifying the identity of colonies stained by the immunofluorescence colony-staining (ifc) procedure was investigated. using primers directed against conserved sequences of the pectate lyase-genes coding for isozymes pla, pld and ple of erwinia chrysanthemi, the authors confirmed the identity of 96% of 20 fluorescent target colonies, punched from ifc-stained samples with pure cultures. in pour plates with mixtures of erw. chrysanthemi and non- ...	1995	8567494
analysis of the erwinia chrysanthemi ferrichrysobactin receptor gene: resemblance to the escherichia coli fepa-fes bidirectional promoter region and homology with hydroxamate receptors.	the fct cbsceba operon from the erwinia chrysanthemi 3937 chrysobactin-dependent iron assimilation system codes for transport and biosynthetic functions. the sequence of the fct outer membrane receptor gene was determined. the fct promoter region displays a strong resemblance to the escherichia coli bidirectional intercistronic region controlling the expression of the fepa-entd and fes-entf operons. an apparent fur-binding site was shown to confer iron regulation on an fct::lac fusion expressed ...	1996	8576065
characterization of erwinia chrysanthemi by pectinolytic isozyme polymorphism and restriction fragment length polymorphism analysis of pcr-amplified fragments of pel genes.	conserved regions about 420 bp long of the pelade cluster specific to erwinia chrysanthemi were amplified by pcr and used to differentiate 78 strains of e. chrysanthemi that were obtained from different hosts and geographical areas. no pcr products were obtained from dna samples extracted from other pectinolytic and nonpectinolytic species and genera. the pel fragments amplified from the e. chrysanthemi strains studied were compared by performing a restriction fragment length polymorphism (rflp) ...	1996	8779560
the role of iron in plant host-pathogen interactions.	iron is unlikely to be readily available in plant tissues for invading microorganisms. soft rot, caused by erwinia chrysanthemi strain 3937 on african violets, is a valuable model for studying the role of iron and its ligands in plant-pathogen interactions. these studies could lead to the development of new control strategies against microbial infections of plants.	1996	8795159
the rsma- mutants of erwinia carotovora subsp. carotovora strain ecc71 overexpress hrpnecc and elicit a hypersensitive reaction-like response in tobacco leaves.	erwinia carotovora subsp. carotovora wild-type strain ecc71 does not elicit the hypersensitive reaction (hr) in tobacco leaves. by mini-tn5-km and chemical mutagenesis we have isolated rsma- mutants of ecc71 that produce high basal levels of pectate lyases, polygalacturonase, cellulase, and protease; they also are hypervirulent. the rsma- mutants, but not their parent strains, elicit an hr-like response in tobacco leaves. this reaction is characterized by the rapid appearance of water soaking fo ...	1996	8810071
cloning and characterization of a xylanase gene from corn strains of erwinia chrysanthemi.	the gene encoding a 42-kda endoxylanase was cloned from erwinia chrysanthemi strain d1. sequencing of this gene, called xyna, showed that it encoded a primary protein product of 413 amino acids with an unusual and long (31 amino acid) leader peptide that was cleaved during secretion to the bacterial periplasm. this protein is distinct from xylanases in glycohydrolase families 10 and 11 and, instead, appears to be intermediate between families 5 and 30. the xyna gene is located downstream from a ...	1996	8810080
regulatory systems modulating the transcription of the pectinase genes of erwinia chrysanthemi are conserved in escherichia coli.	to depolymerize plant pectin, the phytopathogenic enterobacterium erwinia chrysanthemi produces five isoenzymes of pectate lyases encoded by the five genes pela, pelb, pelc, peld and pele. in er. chrysanthemi, all genes involved in pectin degradation are specifically controlled by the kdgr repressor and are induced in the presence of a pectin catabolic product, 2-keto-3-deoxygluconate (kdg). transcription of the pectinase genes is dependent on many environmental conditions. transcriptional fusio ...	1996	8828230
characterization of pectin methylesterase b, an outer membrane lipoprotein of erwinia chrysanthemi 3937.	the secretion of extracellular pectinases, among which there are least six isoenzymes of pectate lyase and one pectin methylesterase, allows the phytopathogenic bacterium erwinia chrysanthemi to degrade pectin. a gene coding for a novel pectin methylesterase has been cloned from an e. chrysanthemi strain 3937 gene library. this gene, pemb, codes for a 433-amino-acid protein. the pemb n-terminal region has the characteristics of lipoprotein signal sequences. we have shown that the pemb precursor ...	1996	8830237
synthesis of optically pure chrysobactin and immunoassay development.	chrysobactin (alpha-n-(2,3-dihydroxybenzoyl)-d-lysyl-l-serine), a siderophore that is essential for systemic virulence by plant pathogenic erwinia chrysanthemi, was synthesized with high diastereomeric purity. chrysobactin was prepared by coupling the n-hydroxysuccinimide ester of alpha-n-(2,3-dibenzyloxybenzoyl)-epsilon-n-cbz-d-lysine with l-serine benzyl ester followed by deprotection via hydrogenolysis. optically pure chrysobactin was obtained with 98% overall yield. a monoclonal antibody to ...	1996	8837459
complementation of deletion mutations in a cloned functional cluster of erwinia chrysanthemi out genes with erwinia carotovora out homologues reveals outc and outd as candidate gatekeepers of species-specific secretion of proteins via the type ii pathway.	the type ii or sec-dependent secretion system is used by diverse gram-negative bacteria for secretion of extracellular proteins. of the 12-15 proteins involved in secretion, the requirement for many has not been demonstrated and little is known about their functions in the secretion process. the plant pathogens erwinia chrysanthemi and erwinia carotovora secrete extra-cellular pectate lyases (pels) using the type ii or out pathway. however, these two bacteria cannot secrete pels encoded by heter ...	1996	8861215
differential effect of site-directed mutations in pelc on pectate lyase activity, plant tissue maceration, and elicitor activity.	oligonucleotide site-directed mutations were introduced into the pelc gene of erwinia chrysanthemi ec16 that directed single or double amino acid changes affecting disulfide linkages, calcium binding, catalysis, and protein folding. subsequent characterization of the purified pelc mutant proteins demonstrated that pectinolytic function involves amino acids located near the calcium binding site rather than those surrounding an invariant vwidh sequence. wild-type pelc and the tested mutant protein ...	1996	8900122
regulation of pectinolysis in erwinia chrysanthemi.	erwinia chrysanthemi is an enterobacterium that causes various plant diseases. its pathogenicity results from the secretion of pectinolytic enzymes responsible for the disorganization of the plant cell wall. the e. chrysanthemi strain 3937 produces two pectin methylesterases, at least seven pectate lyases, a polygalacturonase, and a pectin lyase. the extracellular degradation of the pectin leads to the formation of oligogalacturonides that are catabolized through an intracellular pathway. the pe ...	1996	8905080
comparison of extracellular polysaccharides of erwinia chrysanthemi spp.	two extracellular polysaccharides from strains of erwinia chrysanhemi ech 1 and 9, phytopathogens of potatoes, have been isolated and purified. both have similar compositions and other properties to that produced by strain sr 260, a phytopathogen of corn. these polysaccharides are composed of l-rhamnose, d-mannose, d-glucose, d-glucuronic acid in the ratio 3:1:1:1. initial structural aspects of these polysaccharides are reflected in the 600 mhz 1h nmr spectra and the products of partial acid hyd ...	1996	8910063
protein secretion in gram-negative bacteria: assembly of the three components of abc protein-mediated exporters is ordered and promoted by substrate binding.	one of the strategies used by gram-negative bacteria to secrete proteins across the two membranes which delimit the cells, is sec independent and dedicated to proteins lacking an n-terminal signal peptide. it depends on abc protein-mediated exporters, which consist of three cell envelope proteins, two inner membrane proteins, an atpase (the abc protein), a membrane fusion protein (mfp) and an outer membrane polypeptide. erwinia chrysanthemi metalloproteases b and c and serratia marcescens hemopr ...	1996	8918458
global regulation in erwinia species by erwinia carotovora rsma, a homologue of escherichia coli csra: repression of secondary metabolites, pathogenicity and hypersensitive reaction.	our previous studies revealed that rsma of erwinia carotovora subsp. carotovora strain 71 suppressed the synthesis of the cell density (quorum) sensing signal n-(3-oxohexanoyl)-l-homoserine lactone, the production of extracellular enzymes and tissue macerating ability in soft-rotting erwinia species and that homologues of this negative regulator gene were present in other erwinia species. northern blot data presented here demonstrate that rsma and rsma-like genes are also expressed in soft-rotti ...	1996	8932714
analysis of bacterial carbapenem antibiotic production genes reveals a novel beta-lactam biosynthesis pathway.	carbapenems are beta-lactam antibiotics which have an increasing utility in chemotherapy, particularly for nosocomial, multidrug-resistant infections. strain gs101 of the bacterial phytopathogen, erwinia carotovora, makes the simple beta-lactam antibiotic, 1-carbapen-2-em-3-carboxylic acid. we have mapped and sequenced the erwinia genes encoding carbapenem production and have cloned these genes into escherichia coli where we have reconstituted, for the first time, functional expression of the be ...	1996	8939426
regulation of pelz, a gene of the pelb-pelc cluster encoding a new pectate lyase of erwinia chrysanthemi 3937.	the phytopathogenic enterobacterium erwinia chrysanthemi 3937 produces five major and several secondary endo-pectate lyases encoded by the pel genes. most of these genes are arranged in clusters on the bacterial chromosome. the genomic region surrounding the pelb-pelc cluster was supposed to be involved in the regulation of pelb and pelc synthesis. we demonstrated that the variation of pelb expression resulted from the titration of a regulatory protein by the gene adjacent to pelc. this gene was ...	1996	8955401
reca relieves negative autoregulation of rdga, which specifies a component of the reca-rdg regulatory circuit controlling pectin lyase production in erwinia carotovora ssp. carotovora.	the production of pectin lyase (pnl) in erwinia carotovora ssp. carotovora strain 71 is induced by dna-damaging agents such as mitomycin c (mc). this induction requires functions of reca, rdga and rdgb genes. based upon sequence homology, rdga was predicted to encode a repressor and rdgb was presumed to specify a transcriptional activator. to elucidate the function of rdga, the gene has been over-expressed in escherichia coli, and the 30 kda product purified by ammonium-sulphate precipitation, h ...	1996	8971712
genetic organization of a dna-processing region required for mobilization of a non-self-transmissible plasmid, pec3, isolated from erwinia carotovora subsp. carotovora.	a non-self-transmissible multiple-copy plasmid, pec3, isolated from the phytopathogenic bacterium, erwinia carotovora subsp. carotovora, can be mobilized by an incp-type plasmid. the hybrid plasmid vector, petc3, constructed from pec3 by fusion to markers conferring tcr and cmr, was transferred by conjugation from escherichia coli (ec) to various genera of enterobacteriaceae and to other genera of gram(-) bacteria which included xanthomonas, agrobacterium and rhizobium. deletion analysis and suc ...	1996	8621089
the erwinia chrysanthemi pect gene regulates pectinase gene expression.	a new type of erwinia chrysanthemi mutant displaying a derepressed synthesis of pectate lyase was isolated. the gene mutated in these strains, pect, encodes a 316-amino-acid protein with a size of 34,761 da that belongs to the lysr family of transcriptional activators and presents 61% identity with the e. coli protein lrha. pect represses the expression of pectate lyase genes pelc, peld, pele, pell, and kdgc, activates pelb, and has no effect on the expression of pela or the pectin methylesteras ...	1996	8626286
purification and functional characterization of pecs, a regulator of virulence-factor synthesis in erwinia chrysanthemi.	the erwinia chrysanthemi pecs gene encodes a repressor that negatively regulates the expression of virulence factors such as pectinases or cellulases. the cloned pecs gene was overexpressed using a phage t7 system. the purification of pecs involved deae-anion exchange and tsk-heparin columns and delivered the pecs protein that was purified to homogeneity. the purified repressor displayed an 18 kda apparent molecular mass and an isoelectric point near to neutrality (pl = 6.5). gel-filtration expe ...	1996	8733237
characterization of the erwinia chrysanthemi osmoprotectant transporter gene ousa.	growth of erwinia chrysanthemi in media of elevated osmolarity can be achieved by the uptake and accumulation of various osmoprotectants. this study deals with the cloning and sequencing of the ousa gene-encoded osmoprotectant uptake system a from e. chrysanthemi 3937. ousa belongs to the superfamily of solute ion cotransporters. this osmotically inducible system allows the uptake of glycine betaine, proline, ectoine, and pipecolic acid and presents strong similarities in nucleotide sequence and ...	1996	8550465
immunomagnetic separation of erwinia carotovora subsp. atroseptica from potato peel extracts to improve detection sensitivity on a crystal violet pectate medium or by pcr.	immunomagnetic separation (ims) procedures for the selective separation of erwinia carotovora subsp. atroseptica from potato peel extract were optimized for the recovery of target and removal of non-target bacteria. a streptomycin-resistant strain of erw. carotovora subsp. atroseptica was used in combination with a crystal violet pectate (cvp) medium supplemented with 100 micrograms ml-1 of streptomycin to determine the recovery level of the target bacterium. recovery obtained with a polyclonal ...	1996	9072520
activation of the erwinia carotovora subsp. carotovora pectin lyase structural gene pnla: a role for rdgb.	the activation of pectin lyase (pnl) production in erwinia carotovora subsp. carotovora strain 71 occurs upon dna damage via a unique regulatory circuit involving reca, rdga and rdgb. in a similar pnl-inducible system reconstituted in escherichia coli, the rdgb product was found to activate the expression of pnla, the structural gene for pectin lyase. the kinetic data presented here also show that transcription of pnla followed that of rdgb in er. carotovora subsp. carotovora, indicating a tempo ...	1997	9084157
the general secretion pathway of erwinia carotovora subsp. carotovora: analysis of the membrane topology of outc and outf.	the out gene cluster of erwinia carotovora subsp. carotovora (ecc) encodes the proteins of the type ii or general secretory pathway (gsp) apparatus which is required for secretion of pectinase and cellulase. in this study, fusions between ecc out genes and the topology probe blam were constructed. the ability of out protein domains to export blam across the cytoplasmic membrane in both escherichia coli and the cognate host was utilized to confirm the computer-predicted cytoplasmic membrane topol ...	1997	9084158
l-asparagine-depletion: another opinion.		1997	9093736
comparative analysis of the five major erwinia chrysanthemi pectate lyases: enzyme characteristics and potential inhibitors.	in erwinia chrysanthemi 3937, pectate lyase activity mainly results from the cumulative action of five major isoenzymes, pela to pele. comparison of their amino acid sequences revealed two families, pelb-c and pela-d-e. molecular cloning permitted expression of the different pel genes in escherichia coli and the isolation of each pel independently from the other isoenzymes. we used similar experimental conditions to overproduce and purify the five pels in a one-step chromatography method. we ana ...	1997	9098045
molecular cloning, characterization, and mutagenesis of a pel gene from pseudomonas syringae pv. lachyrmans encoding a member of the erwinia chrysanthemi pelade family of pectate lyases.	the pels gene from pseudomonas syringae pv. lachrymans 859 was cloned by heterologous expression in nonpectolytic p. syringae pv. syringae buvs1, using genomic dna libraries constructed with two novel broad-host-range cosmid vectors, pcpp34 and pcpp47. screening of p. syringae pv. syringae transconjugants for the ability to pit pectate media at ph 6.0 and 8.5 yielded several overlapping clones of the same dna region. ultrathin-layer isoelectric focusing gels, activity-stained with diagnostically ...	1997	9100381
identification of a pathogenicity locus, rpfa, in erwinia carotovora subsp. carotovora subsp. carotovora that encodes a two-component sensor-regulator protein.	a mutant of erwinia carotovora subsp. carotovora, ah2552, created by a mud1 insertion was found to be reduced in plant pathogenicity and deficient in extracellular protease and cellulase activity, although it produced normal levels of pectate lyase and polygalacturonase. a cosmid clone, pec462, was isolated from a wild-type e. carotovora subsp. carotovora dna library that concomitantly restored pathogenicity and protease and cellulase activities of ah2552 to wild-type levels when present in tran ...	1997	9100385
the cyclic amp receptor protein is the main activator of pectinolysis genes in erwinia chrysanthemi.	the main virulence factors of the phytopathogenic bacterium erwinia chrysanthemi are pectinases that cleave pectin, a major constituent of the plant cell wall. although physiological studies suggested that pectinase production in erwinia species is subjected to catabolite repression, the direct implication of the cyclic amp receptor protein (crp) in this regulation has never been demonstrated. to investigate the role of crp in pectin catabolism, we cloned the e. chrysanthemi crp gene by compleme ...	1997	9171393
investigation of physicochemical changes to l-asparaginase during freeze-thaw cycling.	l-asparaginase derived from erwinia chrysanthemi which is being investigated as an alternative to e. coli for the treatment of lymphoblastic leukaemia has been found in our laboratory to lose activity upon exposure to consecutive freeze-thaw cycles. an investigation was undertaken using several techniques to characterize fully the physicochemical changes l-asparaginase is undergoing during freeze-thaw cycling leading to the loss of its activity. a total protein assay suggested that the loss of s ...	1997	9178179
mutual control of the pecs/pecm couple, two proteins regulating virulence-factor synthesis in erwinia chrysanthemi.	the erwinia chrysanthemi pecs mutant displays constitutive production of virulence factors, such as pectinases or cellulases. complementation of the pecs mutation can be obtained in the presence of the pecs wild-type gene on a low-copy-number plasmid. moreover, the resulting plasmid decreases the expression of a pecs::uida chromosomal fusion, indicating the existence of an autoregulation mechanism. this negative autoregulation was confirmed and quantified by analysis of the pecs transcripts usin ...	1997	9194707
characterization of acquired resistance in lesion-mimic transgenic potato expressing bacterio-opsin.	the lesion-mimic mutants of certain plants display necrotic lesions resembling those of the hypersensitive response and activate local and systemic defense responses in the absence of pathogens. we have engineered a lesion-mimic phenotype in transgenic russet burbank potato plants through constitutive expression of a bacterio-opsin (bo) proton pump derived from halobacterium halobium. transgenic potato plants exhibiting a lesion-mimic phenotype had increased levels of salicylic acid and overexpr ...	1997	9204568
the rna molecule csrb binds to the global regulatory protein csra and antagonizes its activity in escherichia coli.	the rna-binding protein csra (carbon storage regulator) is a new kind of global regulator, which facilitates specific mrna decay. a recombinant csra protein containing a metal-binding affinity tag (csra-h6) was purified to homogeneity and authenticated by n-terminal sequencing, matrix-assisted laser desorption/ionization time of flight mass spectrometry, and other studies. this protein was entirely contained within a globular complex of approximately 18 csra-h6 subunits and a single approximatel ...	1997	9211896
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
identification of a bacterial pectin acetyl esterase in erwinia chrysanthemi 3937.	erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. the structural complexity of pectin requires the combined action of several pectinases for its efficient breakdown. three types of pectinases have so far been identified in e. chrysanthemi: two pectin methyl esterases (pema, pemb), a polygalacturonase (pehx), and eight pectate lyases (pela, pelb, pelc, peld, pele, pell, pelz, pelx). we report in this paper the analysis of a ...	1997	9218776
protein secretion by gram-negative bacterial abc exporters--a review.	one of the strategies used by gram-negative bacteria to secrete proteins across the two membranes which delimit the cells is sec-independent and dedicated to proteins lacking an n-terminal signal peptide. most of these proteins display a c-terminal secretion signal located in the last 60 amino acids (aa). using one erwinia chrysanthemi protease, prtg, secreted by such a pathway it was shown that the smallest c-terminal sequence allowing efficient secretion contains the last 29 aa of prtg and tha ...	1997	9224868
characterization of the pect control region from erwinia chrysanthemi 3937.	erwinia chrysanthemi synthesizes and secretes pectate lyases that attack components of the plant cell wall and, therefore, play a major role in the pathogenesis of soft rot disease. we isolated a new mutant (designated pec-1), by tn5 mutagenesis, that displays weak pectate lyase production and decreased motility and mucoidicity. maceration and pathogenicity tests done on different plant organs showed that the pec-1 strain displays a reduced virulence compared to that of the parental strain. the ...	1997	9244282
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
avirulence gene d of pseudomonas syringae pv. tomato may have undergone horizontal gene transfer.	avirulence gene d (avrd) is carried on the b-plasmid of the plant pathogen pseudomonas syringae pv. tomato with plasmid-borne avrd homologs widely distributed among the pseudomonads. we now report sequences in the soft rot pathogen erwinia carotovora that cross-hybridize to avrd suggesting a conserved function beyond avirulence. alternatively, avrd may have been transferred horizontally among species: (i) dna linked to avrd shows evidence of class ii transpositions and contains a novel is3-relat ...	1997	9326365
pectate lyase peli of erwinia chrysanthemi 3937 belongs to a new family.	erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pel4, pelb, pelc, peld, and pele genes and a set of secondary pectate lyases, two of which, pell and pelz, have been already identified. we cloned the peli gene, encoding a ninth pectate lyase of e. chrysanthemi 3937. the peli reading frame is 1,035 bases long, corresponding to a protein of 344 amino acids including a typical amino-terminal signal sequence of 19 amino acids. the purified mature peli protein ...	1997	9393696
the rap and hor proteins of erwinia, serratia and yersinia: a novel subgroup in a growing superfamily of proteins regulating diverse physiological processes in bacterial pathogens.	the enteric bacterium serratia marcescens is an opportunistic human pathogen. the strain atcc39006 makes the red pigment, prodigiosin (pig), and the beta-lactam antibiotic carbapenem (car). mutants were isolated that were concomitantly defective for pig and car production. these mutants were found to have a mutation in the rap gene (regulation of antibiotic and pigment). sequence analysis of the rap gene revealed a predicted protein product showing strong homology to slya, originally thought to ...	1997	9402023
analysis of the carbapenem gene cluster of erwinia carotovora: definition of the antibiotic biosynthetic genes and evidence for a novel beta-lactam resistance mechanism.	members of two genera of gram-negative bacteria, serratia and erwinia, produce a beta-lactam antibiotic, 1-carbapen-2-em-3-carboxylic acid. we have reported previously the cloning and sequencing of the genes responsible for production of this carbapenem in erwinia carotovora. these genes are organized as an operon, cara--h, and are controlled by a luxr-type transcriptional activator, encoded by the linked carr gene. we report in this paper the genetic dissection of this putative operon to determ ...	1997	9402024
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
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
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
elucidation of the structure of the core region and the complete structure of the r-type lipopolysaccharide of erwinia carotovora ferm p-7576.	an r-type lipopolysaccharide (lps) from erwinia carotovora strain ferm p-7576 was studied after strong alkaline degradation and mild acid hydrolysis. the resulting products were analyzed by fast-atom bombardment mass spectrometry, one- and two-dimensional 1h and 13c nmr spectroscopy, dephosphorylation and methylation analysis. the following structure was proposed for the core region of the lps: [formula in text] where hep is l-glycero-d-manno-heptose and kdo is 3-deoxy-d-manno-octulosonic acid. ...	1997	9431990
characterization of erwinia carotovora subsp. carotovora ly34 endo-1,4-beta-glucanase genes and rapid identification of their gene products.	genomic dna of the phytopathogenic erwinia carotovora subsp. carotovora ly34 was partially digested with sau3ai, ligated into the bamhi site of pblue-script ii sk+, and introduced into e. coli. two clones that were able to hydrolyse carboxymethylcellulose were selected. 1.5 kb and 1.2 kb fragments containing the cela and celb genes, respectively, were subcloned and sequenced. the cela and celb genes had open reading frames of 1,161 bp and 792 bp encoding 487 and 264 amino acid residues with calc ...	1997	9434760
the interaction of shikimate kinase from erwinia chrystanthemi with substrates.		1997	9450055
ecbi and ecbr: homologs of luxi and luxr affecting antibiotic and exoenzyme production by erwinia carotovora subsp. betavasculorum.	erwinia carotovora subsp. betavasculorum ecb168 causes vascular necrosis and root rot of sugar beet and produces an antibiotic(s) that is antagonistic against other erwinia spp. ecbi- mutants of ecb168, each containing a single transposon insertion in the ecbi gene (for erwinia carotovora subsp. betavasculorum inducer), do not produce detectable levels of extracellular protease or antibiotic(s), and express less pectate lyase activity and virulence than the wild-type strain. a plasmid containing ...	1997	9476353
characterization of the agrobacterium vitis peha gene and comparison of the encoded polygalacturonase with the homologous enzymes from erwinia carotovora and ralstonia solanacearum.	dna sequencing of the agrobacterium vitis peha gene revealed a predicted protein with an m(r) of 58,000 and significant similarity to the polygalacturonases of two other plant pathogens, erwinia carotovora and ralstonia (= pseudomonas or burkholderia) solanacearum. sequencing of the n terminus of the peha protein demonstrated cleavage of a 34-amino-acid signal peptide from pre-peha. mature peha accumulated primarily in the periplasm of a. vitis and peha+ escherichia coli cells during exponential ...	1997	8979363
isolation and characterization of new c-terminal substitution mutations affecting secretion of polygalacturonase in erwinia carotovora ssp. carotovora.	an intact c-terminus was previously shown to be required for stability and secretion of the polygalacturonase (peha) in erwinia carotovora ssp. carotovora. here we have analyzed the effects of amino acid (aa) substitutions generated to five c-terminal positions of peha. conservation of two hydrophobic and one non-hydrophobic residue (v372, v374 and n371, respectively) was found to be essential for maintenance of the protein stability. as an exception, one of the mutants (v372g) did not show majo ...	1997	9000526
extracellular melibiose and fructose are intermediates in raffinose catabolism during fermentation to ethanol by engineered enteric bacteria.	contrary to general concepts of bacterial saccharide metabolism, melibiose (25 to 32 g/liter) and fructose (5 to 14 g/liter) accumulated as extracellular intermediates during the catabolism of raffinose (o-alpha-d-galactopyranosyl-1, 6-alpha-d-glucopyranosyl-beta-d-fructofuranoside) (90 g/liter) by ethanologenic recombinants of escherichia coli b, klebsiella oxytoca m5a1, and erwinia chrysanthemi ec16. both hydrolysis products (melibiose and fructose) were subsequently transported and further me ...	1997	9068632
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 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
cryptic carbapenem antibiotic production genes are widespread in erwinia carotovora: facile trans activation by the carr transcriptional regulator.	few strains of erwinia carotovora subsp. carotovora (ecc) make carbapenem antibiotics. strain gs101 makes the basic carbapenem molecule, 1-carbapen-2-em-3-carboxylic acid (car). the production of this antibiotic has been shown to be cell density dependent, requiring the accumulation of the small diffusible molecule n-(3-oxohexanoyl)-l-homoserine lactone (ohhl) in the growth medium. when the concentration of this inducer rises above a threshold level, ohhl is proposed to interact with the transcr ...	1998	9639920
the hexa gene of erwinia carotovora encodes a lysr homologue and regulates motility and the expression of multiple virulence determinants.	we have identified a gene important for the regulation of exoenzyme virulence factor synthesis in the plant pathogen erwinia carotovora ssp. carotovora (ecc) and virulence and motility in erwinia carotovora ssp. atroseptica (eca). this gene, hexa (hyperproduction of exoenzymes), is a close relative of the erwinia chrysanthemi (echr) gene pect and encodes a member of the lysr family of transcriptional regulators. hexa mutants in both ecc and eca produce abnormally high levels of the exoenzyme vir ...	1998	9643539