Publications

a left-handed crossover involved in amidohydrolase catalysis. crystal structure of erwinia chrysanthemi l-asparaginase with bound l-aspartate.	the crystal structure of l-asparaginase from erwinia chrysanthemi in the presence and absence of l-aspartate was determined at 1.8 a resolution. conserved residues in a left-handed crossover (a rare occurrence in protein structures) link pairs of dimers into the catalytically active tetrameric form of the enzyme. the structure of era containing bound aspartic acid shows that this unusual strand connectivity is an essential part of the active site architecture, responsible for releasing the produ ...	1993	8348975
structure of an extracellular polysaccharide produced by erwinia chrysanthemi.	erwinia chrysanthemi pv zeae strain sr260, a phytopathogen of corn, produced from lactose an acidic extracellular polysaccharide which was purified and found to consist of l-rhamnose, d-mannose, d-glucose, and d-glucuronic acid in the ratio of 3:1:1:1. a combination of chemical (carboxyl-group reduction, methylation analysis, periodate oxidation, smith degradation, and lithium-ethylenediamine degradation) and physical (1 and 2d nmr spectroscopy) methods revealed that the polysaccharide is compos ...	1993	8370026
characterization and overexpression of the pem gene encoding pectin methylesterase of erwinia chrysanthemi strain 3937.	the pem gene encoding the pectin methylesterase (pme) of erwinia chrysanthemi strain 3937 was subcloned and its nucleotide sequence determined. the gene contains an open reading frame of 1098 bp and codes for a protein of 366 amino acids (aa). the mature 37-kda form of the protein is 342 aa long and has a calculated isoelectric point of 9.64. a plasmid was constructed to overproduce pme: a dna fragment carrying pem was amplified by the polymerase chain reaction and cloned downstream from the pl ...	1993	8370537
[expression of pel genes of erwinia chrysanthemi ena49 in erwinia carotovora var. atroseptica 36a cells].	erwinia atroseptica 36a cells were transformed by the recombinant plasmid ppl5-1 (a derivative of the vector plasmid puc19) containing pelb and pelc genes which encode pectate lyases of erwinia chrysanthemi ena49. synthesis of pectate lyases plb and plc determined by the cloned pel genes is constitutive in erwinia atroseptica 36appl5-1 cells and not inducible by sodium polypectate. the major part of these enzymes was accumulated in the periplasmic fraction of erwinia atroseptica and cells were u ...	1993	8371722
cloning and sequence analysis of a gene (pchr) encoding an arac family activator of pyochelin and ferripyochelin receptor synthesis in pseudomonas aeruginosa.	pseudomonas aeruginosa k372 is deficient in the production of both the 75-kda ferripyochelin receptor protein and pyochelin. a 1.8-kb ecori-sali fragment which restored production of both the receptor protein and pyochelin was cloned. nucleotide sequencing of the fragment revealed an open reading frame of 888 bp, designated pchr (pyochelin), capable of encoding a 296-amino-acid protein of a 32,339-da molecular mass. by using a phage t7-based expression system, a protein of ca. 32 kda was produce ...	1993	8397186
involvement of lipopolysaccharide in the secretion of escherichia coli alpha-haemolysin and erwinia chrysanthemi proteases.	the presence of the alpha-haemolysin secretion genes sensitizes escherichia coli to vancomycin, a glycopeptide antibiotic that is normally excluded from the gram-negative envelope (owing to its large size) (m(r) 1400). the selection of vancomycin mutants in strains carrying such genes was found to be a very powerful method for selecting non-haemolytic mutants. in this way, mutations in the known secretion genes, hlyb, hlyd and tolc, were obtained. however additional mutations mapped in genes rfa ...	1993	8437516
regulation of the expression of a pela::uida fusion in erwinia chrysanthemi and demonstration of the synergistic action of plant extract with polygalacturonate on pectate lyase synthesis.	the phytopathogenicity of erwinia chrysanthemi is chiefly supported by the production of pectate lyase isoenzymes, encoded by the pel genes. one of these enzymes, pela, encoded by the pela gene, seems to represent only a small part of the total pectate lyase activity, but is required for full bacterial pathogenicity. to study the regulation of pela gene expression, a pela::uida gene fusion was constructed. expression of this fusion was analysed under various growth conditions and in various gene ...	1993	8450303
mutagenesis of cellulase egz for studying the general protein secretory pathway in erwinia chrysanthemi.	extracellular secretion of endoglucanase z (egz) from erwinia chrysanthemi is mediated by the so-called out general secretion pathway and, presumably, involves recognition of egz-carried structural information by one or more of the out proteins. investigating the relationships between structure and secretability of egz was the purpose of the present work. egz is made of two independent domains, located at the n- and c-proximal sides, separated by a ser/thr-rich region, which are responsible for ...	1993	8469118
new domain motif: the structure of pectate lyase c, a secreted plant virulence factor.	pectate lyases are secreted by pathogens and initiate soft-rot diseases in plants by cleaving polygalacturonate, a major component of the plant cell wall. the three-dimensional structure of pectate lyase c from erwinia chrysanthemi has been solved and refined to a resolution of 2.2 angstroms. the enzyme folds into a unique motif of parallel beta strands coiled into a large helix. within the core, the amino acids form linear stacks and include a novel asparagine ladder. the sequence similarities ...	1993	8502994
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
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 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
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
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 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
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
use of recombinase gene fusions to identify vibrio cholerae genes induced during infection.	a complete understanding of host-parasite interactions must necessarily include the identification and characterization of gene products expressed by both parties during the infectious process. we have developed a new screen to identify bacterial genes that are transcriptionally induced during infection of a host animal. the method is based on pre-selection of strains carrying tnpr operon fusions (encoding resolvase, a site-specific dna recombinase) which are not expressed in vitro, followed by ...	1995	8817490
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
role of lysine, tryptophan and calcium in the beta-elimination activity of a low-molecular-mass pectate lyase from fusarium moniliformae.	an extracellular pectate lyase from fusarium moniliformae was purified to homogeneity by affinity chromatography followed by gel filtration, with a yield of 76.5%. laser desorption ms of the enzyme gave a molecular mass of 12,133.5 +/- 2.5 da. the pectate lyase was a glycoprotein with a 5% carbohydrate content and had a pl value of 9.1. atomic-emission spectrometry showed that ca2+ was a part of the holoenzyme held by carboxy groups of the protein. these results support the hypothesis of a putat ...	1996	8870663
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
l-asparagine depletion in plasma and cerebro-spinal fluid of children with acute lymphoblastic leukemia during subsequent exposures to erwinia l-asparaginase.	monitoring l-asparagine (l-asn) plasma levels could provide information useful for determining whether the dosage or schedule of l-asparaginase (l-ase) administration is adequate. very few data are available on depletion caused by the erwinia chrysanthemi (e. chrysanthemi) product. since it has been suggested that l-asn depletion may have been overestimated in the past due to residual l-ase activity, samples in this study have been analyzed after deproteinization with sulphosalicylic acid. patie ...	1996	8905031
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
an in vivo pathway for disulfide bond isomerization in escherichia coli.	biochemical studies have shown that the periplasmic protein disulfide oxidoreductase dsbc can isomerize aberrant disulfide bonds. here we present the first evidence for an in vivo role of dsbc in disulfide bond isomerization. furthermore, our data suggest that the enzymes dsba and dsbc play distinct roles in the cell in disulfide bond formation and isomerization, respectively. we have shown that mutants in dsbc display a defect in disulfide bond formation specific for proteins with multiple disu ...	1996	8917542
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
cloning of the serratia marcescens hasf gene encoding the has abc exporter outer membrane component: a tolc analogue.	the serratia marcescens haemophore hasa is secreted by an abc exporter comprising three envelope proteins. the abc protein (atp-binding cassette) hasd and the mfp protein (membrane fusion protein) hase but not the outer membrane component have been isolated previously. in escherichia coli, tolc, the outer membrane component of the haemolysin transporter, can form a hybrid exporter with hasd and hase. this hybrid secretes hasa and the very similar metalloproteases from s. marcescens and erwinia c ...	1996	8930911
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
the secretin-specific, chaperone-like protein of the general secretory pathway: separation of proteolytic protection and piloting functions.	the chaperone-like protein of the main terminal branch of the general secretory pathway from klebsiella oxytoca, the outer membrane lipoprotein puls, protects the multimeric secretin puld from degradation and promotes its correct localization to the outer membrane. to determine whether these are separable functions, or whether resistance to proteolysis results simply from correct localization of puld, we replaced the lipoprotein-type signal peptide of puls by the signal peptide of periplasmic ma ...	1996	8971717
spectroscopic studies of the c-terminal secretion signal of the serratia marcescens haem acquisition protein (hasa) in various membrane-mimetic environments.	the structure of a peptide comprising the last 56 c-terminal residues of the serratia marcescens haem acquisition protein (hasa) secreted by an atp-binding cassette exporter was examined by 1h-nmr, circular dichroic and fluorescence spectroscopies. the peptide, which contains the secretion signal of hasa, is efficiently secreted by the hasa transporter. it is largely unstructured and flexible in aqueous buffer solution, but its helical content increases upon addition of trifluoroethanol, deterge ...	1997	9030765
antitermination of transcription of catabolic operons.	antitermination of transcription mediated by proteins interacting with mrna sequences is described for nine operons/regulons. eight of the systems are catabolic, while the ninth, the klebsiella pneumoniae nas regulon, is involved in the assimilation of nitrate and nitrite. six of the catabolic operons/regulons are found in bacillus subtilis, one is found in escherichia coli, and one in pseudomonas aeruginosa. the antitermination system of five of the operons/regulons (e. coli blg, and sacpa, sac ...	1997	9044276
the lac operon of lactobacillus casei contains lact, a gene coding for a protein of the bg1g family of transcriptional antiterminators.	the 5' region of the lac operon of lactobacillus casei has been investigated. an open reading frame of 293 codons, designated lact, was identified upstream of lace. the gene product encoded by lact is related to the family of transcriptional antiterminator proteins, which includes bglg from escherichia coli, arbg from erwinia chrysanthemi, sact, sacy, and lict from bacillus subtilis, and bglr from lactococcus lactis. amino acid sequence identities range from 35 to 24%, while similarities range f ...	1997	9045813
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
pharmacokinetics and drug monitoring of l-asparaginase treatment.	the enzyme l-asparaginase is an important component of the treatment protocols for acute lymphoblastic leukemia (all). this enzyme is derived from different biological sources (e. coli and erwinia chrysanthemi). an increasing number of hemorrhagic and thrombotic events prompted us to initiate a monitoring program for asparaginase treatment. different asparaginase preparations were monitored in children on the all-bfm induction and reinduction treatment (10,000 u/m2 every 3-4 days). the different ...	1997	9088996
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
creation of libraries with long orfs by polymerization of a microgene.	we describe a novel method for constructing pools of dna sequences that encode large proteins with molecular diversity. sets of primer pairs that form 8 to 10 complementary base pairs in the 3' region and have double mismatch pairs at their 3'-oh ends were designed so that primer dimers recreated short stretches of dna (microgenes) devoid of termination codons. cycles of denaturation and elongation reactions with a pair of primers, four dntps, and 3'-5' exo+ thermostable dna polymerase gave head ...	1997	9108059
identification of genes in rhizobium leguminosarum bv. trifolii whose products are homologues to a family of atp-binding proteins.	the specific interaction between rhizobia and their hosts requires many genes that influence both early and late steps in symbiosis. three new genes, designated prsd, prse (protein secretion) and orf3, were identified adjacent to the exo133 mutation in a cosmid carrying the genomic dna of rhizobium leguminosarum bv. trifolii ta1. the prsde genes share significant homology to the genes encoding abc transporter proteins prtde from erwinia chrysanthemi and aprde from pseudomonas aeruginosa which ex ...	1997	9141701
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
detection of rtx toxin genes in gram-negative bacteria with a set of specific probes.	the family of rtx (rtx representing repeats in the structural toxin) toxins is composed of several protein toxins with a characteristic nonapeptide glycine-rich repeat motif. most of its members were shown to have cytolytic activity. by comparing the genetic relationships of the rtx toxin genes we established a set of 10 gene probes to be used for screening as-yet-unknown rtx toxin genes in bacterial species. the probes include parts of apxia, apxiia, and apxiiia from actinobacillus pleuropneumo ...	1997	9172345
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
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
longus pilus of enterotoxigenic escherichia coli and its relatedness to other type-4 pili--a minireview.	longus is a long pilus produced by human enterotoxigenic escherichia coli (etec) which shares significant structural and biochemical features with class-b type-4 pili. these pili include the toxin-coregulated pilus (tcp) of vibrio cholerae, the bundle-forming pilus (bfp) of enteropathogenic e. coli and both longus and the colonization factor antigen iii (cfa/iii) of etec. these pili are produced under defined growth conditions indicating that they are under the control of different regulatory el ...	1997	9224872
lipase secretion by bacterial hybrid atp-binding cassette exporters: molecular recognition of the lipbcd, prtdef, and hasdef exporters.	serratia marcescens secretes several proteins, such as the lipase lipa, the metalloprotease prta, and the heme-binding protein hasa, which is required for heme acquisition, through two n-terminal signal peptide-independent systems that are classified as bacterial atp-binding cassette (abc) exporters. one is the abc exporter for hasa, consisting of the abc protein hasd, the membrane fusion protein (mfp) hase, and the outer membrane protein (omp) hasf. the second, composed of lipb (an abc protein) ...	1997	9244262
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
protein secretion by gram-negative bacterial abc exporters.	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 metalloproteinases b and c, and serratia marcescens hem ...	1997	9246759
in vitro and in vivo redox states of the escherichia coli periplasmic oxidoreductases dsba and dsbc.	dsbc is a periplasmic protein of escherichia coli that was previously identified by a genetic selection that rescued sensitivity to dithiothreitol in tn10 mutagenized cells. the erwinia chrysanthemi dsbc gene was identified in a previous genetic screen to restore motility in a dsba null strain. in order to analyze the biochemical role of e. coli dsbc, the protein was overexpressed, purified, and compared with dsba in terms of disulfide isomerization, thiol oxidation, and in vivo redox state. in ...	1997	9254601
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
phylogenetic analysis of erwinia species based on 16s rrna gene sequences.	the phylogenetic relationships of the type strains of 16 erwinia species were investigated by performing a comparative analysis of the sequences of the 16s rrna genes of these organisms. the sequence data were analyzed by the neighbor-joining method, and each branch was supported by moderate bootstrap values. the phylogenetic tree and sequence analyses confirmed that the genus erwinia is composed of species that exhibit considerable heterogeneity and form four clades that are intermixed with mem ...	1997	9336906
bacterial flavohaemoglobins: a consensus sequence and identification of a discrete enterobacterial group and of further bacterial globins.	the amino acid sequences of haemoglobin-like proteins from the bacteria alcaligenes eutrophus, bacillus subtilis, erwinia chrysanthemi, escherichia coli, vibrio parahaemolyticus, vitreoscilla sp. and the yeast saccharomyces cerevisiae were studied. phylogenies based on distance and parsimony analysis showed that the eubacterial group can be easily distinguished from the other haemoglobin-like proteins. the construction of a consensus bacterial flavohaemoglobin based on the alignment of six bacte ...	1997	9351199
use of model plant hosts to identify pseudomonas aeruginosa virulence factors.	we used plants as an in vivo pathogenesis model for the identification of virulence factors of the human opportunistic pathogen pseudomonas aeruginosa. nine of nine tnphoa mutant derivatives of p. aeruginosa strain ucbpp-pa14 that were identified in a plant leaf assay for less pathogenic mutants also exhibited significantly reduced pathogenicity in a burned mouse pathogenicity model, suggesting that p. aeruginosa utilizes common strategies to infect both hosts. seven of these nine mutants contai ...	1997	9371831
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
an exo-poly-alpha-d-galacturonosidase, pehb, is required for wild-type virulence of ralstonia solanacearum.	ralstonia solanacearum, which causes bacterial wilt disease of many plant species, produces several extracellular plant cell wall-degrading enzymes that are suspected virulence factors. these include a previously described endopolygalacturonase (pg), peha, and two exo-pgs. a gene encoding one of the exo-pgs, pehb, was cloned from r. solanacearum k60. the dna fragment specifying pehb contained a 2,103-bp open reading frame that encodes a protein of 74.2 kda with a typical n-terminal signal sequen ...	1997	9393701
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
complementation analysis of the dichelobacter nodosus fimn, fimo, and fimp genes in pseudomonas aeruginosa and transcriptional analysis of the fimnop gene region.	the causative agent of ovine footrot, the gram-negative anaerobe dichelobacter nodosus, produces polar type iv fimbriae, which are the major protective antigens. the d. nodosus genes fimn, fimo, and fimp are homologs of the pseudomonas aeruginosa fimbrial assembly genes, pilb, pilc, and pild, respectively. both the pild and fimp genes encode prepilin peptidases that are responsible for cleavage of the leader sequence from the immature fimbrial subunit. to investigate the functional similarity of ...	1998	9423871
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
cloning, sequence and expression of the pel gene from an amycolata sp.	the pel gene from an amycolata sp. encoding a pectate lyase (ec 4.2.2.2) was isolated by activity screening a genomic dna library in streptomyces lividans tk24. subsequent subcloning and sequencing of a 2.3 kb bamhi bglii fragment revealed an open reading frame of 930 nt corresponding to a protein of 29,660 da. the overall g + c content for the coding region was 65%, with a strong g + c preference in the third (wobble) codon position (93%). a putative ribosome-binding site 5'-gggag-3' preceded t ...	1997	9427544
identification of a linked set of genes in serpulina hyodysenteriae (b204) predicted to encode closely related 39-kilodalton extracytoplasmic proteins.	a tandem pair of nearly identical genes from serpulina hyodysenteriae (b204) were cloned and sequenced. the full open reading frame of one gene and the partial open reading frame of the neighboring gene appear to encode secreted proteins which are homologous to, yet distinct from, the 39-kda extracytoplasmic protein purified from the membrane fraction of s. hyodysenteriae. we have designated these newly identified genes vspa and vspb (for variable surface protein).	1998	9440540
the tree-dimensional structure of aspergillus niger pectin lyase b at 1.7-a resolution.	the three-dimensional structure of aspergillus niger pectin lyase b (plb) has been determined by crystallographic techniques at a resolution of 1.7 a. the model, with all 359 amino acids and 339 water molecules, refines to a final crystallographic r factor of 16.5%. the polypeptide backbone folds into a large right-handed cylinder, termed a parallel beta helix. loops of various sizes and conformations protrude from the central helix and probably confer function. the largest loop of 53 residues f ...	1998	9449837
sacy, a transcriptional antiterminator from bacillus subtilis, is regulated by phosphorylation in vivo.	sacy antiterminates transcription of the sacb gene in bacillus subtilis in response to the presence of sucrose in the growth medium. we have found that it can substitute for bglg, a homologous protein, in antiterminating transcription of the bgl operon in escherichia coli. we therefore sought to determine whether, similarly to bglg, sacy is regulated by reversible phosphorylation in response to the availability of the inducing sugar. we show here that two forms of sacy, phosphorylated and nonpho ...	1998	9457872
the secb chaperone is involved in the secretion of the serratia marcescens hasa protein through an abc transporter.	the secretion pathways of the heme-binding protein hasa from serratia marcescens and of the metalloproteases a, b, c and g from erwinia chrysanthemi have been reconstituted in escherichia coli. they are secreted in a single step from the cytoplasm across both membranes of the gram-negative envelope, after recognition of their specific c-terminal secretion signal by their cognate abc transporter. we report strong evidence that both hasa and the metalloproteases bind the secb chaperone involved in ...	1998	9463372
expression and regulation of the arsenic resistance operon of acidiphilium multivorum aiu 301 plasmid pkw301 in escherichia coli.	the arsenic resistance (ars) operon from plasmid pkw301 of acidiphilium multivorum aiu 301 was cloned and sequenced. this dna sequence contains five genes in the following order: arsr, arsd, arsa, arsb, arsc. the predicted amino acid sequences of all of the gene products are homologous to the amino acid sequences of the ars gene products of escherichia coli plasmid r773 and incn plasmid r46. the ars operon cloned from a. multivorum conferred resistance to arsenate and arsenite on e. coli. expres ...	1998	9464374
biochemical and genetic characterization of an extracellular protease from pseudomonas fluorescens cy091.	pseudomonas fluorescens cy091 cultures produce an extracellular protease with an estimated molecular mass of 50 kda. production of this enzyme (designated aprx) was observed in media containing cacl2 or srcl2 but not in media containing zncl2, mgcl2, or mncl2. the requirement of ca2+ (or sr2+) for enzyme production was concentration dependent, and the optimal concentration for production was determined to be 0.35 mm. following ammonium sulfate precipitation and ion-exchange chromatography, the a ...	1998	9501431
when an atpase is not an atpase: at low temperatures the c-terminal domain of the abc transporter cvab is a gtpase.	the atp-binding cassette (abc) transporters belong to a large superfamily of proteins which share a common function and a common nucleotide-binding domain. the cvab protein from escherichia coli is a member of the bacterial abc exporter subfamily and is essential for the export of the peptide antibiotic colicin v. here we report that, surprisingly, the cvab carboxyl-terminal nucleotide-binding domain (bctd) can be preferentially cross-linked to gtp but not to atp at low temperatures. the cross-l ...	1998	9515899
external loops at the c terminus of erwinia chrysanthemi pectate lyase c are required for species-specific secretion through the out type ii pathway.	the type ii secretion system (main terminal branch of the general secretion pathway) is used by diverse gram-negative bacteria to secrete extracellular proteins. proteins secreted by this pathway are synthesized with an n-terminal signal peptide which is removed upon translocation across the inner membrane, but the signals which target the mature proteins for secretion across the outer membrane are unknown. the plant pathogens erwinia chrysanthemi and erwinia carotovora secrete several isozymes ...	1998	9515910
pcau, a transcriptional activator of genes for protocatechuate utilization in acinetobacter.	the acinetobacter pcaijfbdkchg operon encodes the six enzymes that convert protocatechuate to citric acid cycle intermediates. directly downstream from the operon are qui and pob genes encoding sets of enzymes that convert quinate and p-hydroxybenzoate, respectively, to protocatechuate. prior to this investigation, the only known regulatory gene in the pca-qui-pob cluster was pobr, which encodes a transcriptional activator that responds to p-hydroxybenzoate and activates transcription of poba. t ...	1998	9515921
the leu-3 residue of serratia marcescens metalloprotease inhibitor is important in inhibitory activity and binding with serratia marcescens metalloprotease.	serratia marcescens metalloprotease inhibitor (smapi) is a proteinase inhibitor toward serratia marcescens metalloprotease (smp). in sequential deletion analysis of the n-terminal region of the smapi, smapis starting at ser-2 and leu-3 residues, respectively, had nearly a full inhibitory activity toward smp. however, smapi starting at ala-4 residue showed severely decreased inhibitory activity. furthermore, kinetic analysis demonstrated that smapi starting at the ala-4 residue had an inhibition ...	1998	9521810
major facilitator superfamily.	the major facilitator superfamily (mfs) is one of the two largest families of membrane transporters found on earth. it is present ubiquitously in bacteria, archaea, and eukarya and includes members that can function by solute uniport, solute/cation symport, solute/cation antiport and/or solute/solute antiport with inwardly and/or outwardly directed polarity. all homologous mfs protein sequences in the public databases as of january 1997 were identified on the basis of sequence similarity and sho ...	1998	9529885
the exut gene of erwinia chrysanthemi ec16: nucleotide sequence, expression, localization, and relevance of the gene product.	galacturonic acid (galua) is a major component of pectin and polygalacturonic acid in the plant cell wall. in the phytopathogen erwinia chrysanthemi, the uptake of molecules derived from degradation of these polymers is an important early step in the events preceding induction of pectinases, ultimately leading to plant tissue maceration. uptake systems for galua and dimers of galua have been described and shown to be inducible in e. chrysanthemi. the galua uptake gene (exut) was cloned and seque ...	1998	9530868
characterization of rhizobium leguminosarum exopolysaccharide glycanases that are secreted via a type i exporter and have a novel heptapeptide repeat motif.	the prsde genes encode a type i protein secretion system required for the secretion of the nodulation protein nodo and at least three other proteins from rhizobium leguminosarum bv. viciae. at least one of these proteins was predicted to be a glycanase involved in processing of bacterial exopolysaccharide (eps). two strongly homologous genes (plya and plyb) were identified as encoding secreted proteins with polysaccharide degradation activity. both plya and plyb degrade eps and carboxymethyl cel ...	1998	9537364
cloning and characterization of the pseudomonas aeruginosa zwf gene encoding glucose-6-phosphate dehydrogenase, an enzyme important in resistance to methyl viologen (paraquat).	in this study, we cloned the pseudomonas aeruginosa zwf gene, encoding glucose-6-phosphate dehydrogenase (g6pdh), an enzyme that catalyzes the nad+- or nadp+-dependent conversion of glucose-6-phosphate to 6-phosphogluconate. the predicted zwf gene product is 490 residues, which could form a tetramer with a molecular mass of approximately 220 kda. g6pdh activity and zwf transcription were maximal in early logarithmic phase when inducing substrates such as glycerol, glucose, or gluconate were abun ...	1998	9537370
targeted mutants of cochliobolus carbonum lacking the two major extracellular polygalacturonases.	the filamentous fungus cochliobolus carbonum produces endo-alpha 1,4-polygalacturonase (endopg), exo-alpha 1,4-polygalacturonase (exopg), and pectin methylesterase when grown in culture on pectin. residual activity in a pgn1 mutant (lacking endopg) was due to exopg activity, and the responsible protein has now been purified. after chemical deglycosylation, the molecular mass of the purified protein decreased from greater than 60 to 45 kda. the gene that encodes exopg, pgx1, was isolated with pcr ...	1998	9546185
transformation of acinetobacter sp. strain bd413 by transgenic sugar beet dna.	the ability of acinetobacter sp. strain bd413(pfg4 delta nptii) to take up and integrate transgenic plant dna based on homologous recombination was studied under optimized laboratory conditions. restoration of nptii, resulting in kanamycin-resistant transformants, was observed with plasmid dna, plant dna, and homogenates carrying the gene nptii. molecular analysis showed that some transformants not only restored the 317-bp deletion but also obtained additional dna.	1998	9546192
enterocins l50a and l50b, two novel bacteriocins from enterococcus faecium l50, are related to staphylococcal hemolysins.	enterocin l50 (entl50), initially referred to as pediocin l50 (l. m. cintas, j. m. rodríguez, m. f. fernández, k. sletten, i. f. nes, p. e. hernández, and h. holo, appl. environ. microbiol. 61:2643-2648, 1995), is a plasmid-encoded broad-spectrum bacteriocin produced by enterococcus faecium l50. it has previously been purified from the culture supernatant and partly sequenced by edman degradation. in the present work, the nucleotide sequence of the entl50 locus was determined, and several putati ...	1998	9555877
endogenous cellulases in animals: isolation of beta-1, 4-endoglucanase genes from two species of plant-parasitic cyst nematodes.	beta-1,4-endoglucanases (egases, ec 3.2.1.4) degrade polysaccharides possessing beta-1,4-glucan backbones such as cellulose and xyloglucan and have been found among extremely variegated taxonomic groups. although many animal species depend on cellulose as their main energy source, most omnivores and herbivores are unable to produce egases endogenously. so far, all previously identified egase genes involved in the digestive system of animals originate from symbiotic microorganisms. here we report ...	1998	9560201
regulation of the carnitine pathway in escherichia coli: investigation of the cai-fix divergent promoter region.	the divergent structural operons caitabcde and fixabcx of escherichia coli are required for anaerobic carnitine metabolism. transcriptional monocopy lacz fusion studies showed that both operons are coexpressed during anaerobic growth in the presence of carnitine, respond to common environmental stimuli (like glucose and nitrate), and are modulated positively by the same general regulators, crp and fnr, and negatively by h-ns. overproduction of the caif specific regulatory protein mediating the c ...	1998	9573142
isolation of an escherichia coli k-12 mutant strain able to form biofilms on inert surfaces: involvement of a new ompr allele that increases curli expression.	classical laboratory strains of escherichia coli do not spontaneously colonize inert surfaces. however, when maintained in continuous culture for evolution studies or industrial processes, these strains usually generate adherent mutants which form a thick biofilm, visible with the naked eye, on the wall of the culture apparatus. such a mutant was isolated to identify the genes and morphological structures involved in biofilm formation in the very well characterized e. coli k-12 context. this mut ...	1998	9573197
the three-dimensional structure of shikimate kinase.	the three-dimensional structure of shikimate kinase from erwinia chrysanthemi has been determined by multiple isomorphous replacement. two models are presented: a high resolution 1.9 a model and a 2.6 a model which contains bound mg-adp. the enzyme is an alpha/beta protein consisting of a central sheet of five parallel beta-strands flanked by alpha-helices with overall topology similar to adenylate kinase. evidence is presented that shikimate kinase undergoes major conformational changes on liga ...	1998	9600856
biochemical characterization of the pectate lyase pelz of erwinia chrysanthemi 3937.	to degrade the plant pectin, the phytopathogenic bacterium erwinia chrysanthemi produces a set of at least seven endo-pectate lyases (pels). five major (pela, pelb, pelc, peld and pele) and two minor isoenzymes (pell and pelz) have been identified. pelz is an extracellular enzyme secreted by the out system. according to its amino acid sequence, the pelz protein belongs to a new family. the pelz protein was overproduced in e. coli and purified to compare its enzymatic properties to that of the ot ...	1998	9602123
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
acylation of escherichia coli hemolysin: a unique protein lipidation mechanism underlying toxin function.	the pore-forming hemolysin (hlya) of escherichia coli represents a unique class of bacterial toxins that require a posttranslational modification for activity. the inactive protoxin pro-hlya is activated intracellularly by amide linkage of fatty acids to two internal lysine residues 126 amino acids apart, directed by the cosynthesized hlyc protein with acyl carrier protein as the fatty acid donor. this action distinguishes hlyc from all bacterial acyltransferases such as the lipid a, lux-specifi ...	1998	9618444
type iii protein secretion systems in bacterial pathogens of animals and plants.	various gram-negative animal and plant pathogens use a novel, sec-independent protein secretion system as a basic virulence mechanism. it is becoming increasingly clear that these so-called type iii secretion systems inject (translocate) proteins into the cytosol of eukaryotic cells, where the translocated proteins facilitate bacterial pathogenesis by specifically interfering with host cell signal transduction and other cellular processes. accordingly, some type iii secretion systems are activat ...	1998	9618447
the caulobacter crescentus paracrystalline s-layer protein is secreted by an abc transporter (type i) secretion apparatus.	caulobacter crescentus is a gram-negative bacterium that produces a two-dimensional crystalline array on its surface composed of a single 98-kda protein, rsaa. secretion of rsaa to the cell surface relies on an uncleaved c-terminal secretion signal. in this report, we identify two genes encoding components of the rsaa secretion apparatus. these components are part of a type i secretion system involving an abc transporter protein. these genes, lying immediately 3' of rsaa, were found by screening ...	1998	9620954
inactivation of the sapa to sapf locus of erwinia chrysanthemi reveals common features in plant and animal bacterial pathogenesis.	we investigated the role in pathogenesis of bacterial resistance to plant antimicrobial peptides. the sapa to sapf (for sensitive to antimicrobial peptides) operon from the pathogenic bacterium erwinia chrysanthemi has been characterized. it has five open reading frames that are closely related (71% overall amino acid identity) and are in the same order as those of the sapa to sapf operon from salmonella typhimurium. an e. chrysanthemi sap mutant strain was constructed by marker exchange. this m ...	1998	9634580
"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
macromolecular assembly and secretion across the bacterial cell envelope: type ii protein secretion systems.	a decade ago, pugsley and colleagues reported the existence of a large region of klebsiella dna, distinct from the klebsiella gene encoding pullulanase, which was necessary for secretion of this enzyme to the cell surface in escherichia coli (d'enfert et al., 1987a,b). the pul genes it contained proved to be the tip of an iceberg. the sequences reported before 1992 (d'enfert et al., 1987a,b; d'enfert & pugsley, 1989; pugsley & reyss, 1990; reyss & pugsley, 1990) included only one gene (puld) tha ...	1998	9641973
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
construction and expression of a bifunctional single-chain antibody against bacillus cereus p6ores.	the variable-region genes of monoclonal antibody against bacillus cereus spores were cloned from mouse hybridoma cells by reverse transcription-pcr. the heavy- and light-chain variable-region genes were connected by a 45-base linker dna to allow folding of the fusion protein into a functional tertiary structure. for detection of protein expression, a 10-amino-acid strep tag (biotin-like peptide) was attached to the c terminus of recombinant antibody as the reporter peptide. the single-chain anti ...	1998	9647820
development of a streptavidin-conjugated single-chain antibody that binds bacillus cereus spores.	control of microorganisms such as bacillus cereus spores is critical to ensure the safety and a long shelf life of foods. a bifunctional single chain antibody has been developed for detection and binding of b. cereus t spores. the genes that encode b. cereus t spore single-chain antibody and streptavidin were connected for use in immunoassays and immobilization of the recombinant antibodies. a truncated streptavidin, which is smaller than but has biotin binding ability similar to that of strepta ...	1998	9647821
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