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At least 325 records · Page 18Linked to original sources
PubMed2004

[Genetic regulation of pathogenicity and virulence factors in bacteria Erwinia carotovora subsp. atroseptica: identification of kduD gene].

A mutant that cannot utilize pectin substances of plant cell walls was obtained via insertion of mini-mini-Tn5xylE transposon into the chromosome of phytopathogenic bacteria Erwinia carotovora subsp. atroseptica. The inability of mutant cells to utilize these substrates was caused by a failure to accomplish the catabolism of unsaturated digalacturonic acid (UDA). Study of enzymatic activities has established that mutant bacteria lost the ability to produce 2,5-diketo-3-deoxygluconate dehydrogenase, an enzyme of intracellular UDA utilization. Molecular cloning of the mutant gene was conducted, and its nucleotide sequence was determined. It was shown that the nucleotide sequence of this gene had an 82% homology with the sequence of Erwinia chrysanthemi EC3937 kduD gene encoding 2,5-diketo-3-deoxygluconate dehydrogenase. The intergene kdul-kduD region in bacteria Erwinia carotovora subsp. atroseptica is shorter in length by 98 nucleotides than the corresponding region of Erwinia chrysanthemi and does not contain promoter sequences. The kduD gene was located at 126.8 min of the Erwinia carotovora subsp. atroseptica genetic map.

Base Sequence↗
PubMed2004

[Genetic regulation of pathogenicity and virulence factors in bacteria Erwinia carotovora subsp. atroseptica: phenotypic characteristic of bacteria with the mutant kduD gene].

In contrast to the closely related bacteria Erwinia chrysanthemi, bacteria Erwinia carotovora subsp. atroseptica produce lower levels of main pathogenicity and virulence factors (pectate lyases, cellulases, and proteases) in the presence of pectins. This effect was shown to be connected with the accumulation of the intermediate product of intracellular degradation of these substances, 2,5-diketo-3-deoxygluconate (DK2). The presence of DK2 in the culture broth of mutant bacteria, connected to its export in the environment, was established. The production of pectate lyases, cellulases, and proteases is repressed by DK2 only at its high concentrations in the cultivation medium, whereas low concentrations of DK2 induce the production of virulence factors. Genes involved in the intracellular catabolism of pectin substances and induced by both low and high DK2 concentrations in the cultivation medium are not repressed by this metabolite.

Cellulase↗
PubMed2005

[O2-* burst of tobacco leaves triggered by Erwinia carotovora subsp. carotovora inoculation].

O(-.)(2) production based on chemical method by Ecc-treated intact tobacco leaves was observed. It showed a long-lasting one-phase course beginning 1 h and ending 14 h after Erwinia carotovora subsp. carotovora (Ecc) was inoculated. In Ecc-treated leaves, O(-.)(2) production rate of 3 h is 2 times of 1 h, and of 10 h it remains 1.7 times. It decreases rapidly between 10 h and 14 h, at 14 h it falls to the level before inoculation. This is a completely different course from the widely accepted two-phase course obtained from suspension-cultured cells. Electron spin resonance (ESR) spectrum of O(-.)(2) produced by intact tobacco leaves after Ecc inoculation 2 h and 6 h was also observed, the amplitude of 6 h is larger than of 2 h in Ecc-treated group. In the control group, there is no difference between the amplitude of 2 h and 6 h. This indicated that O(-.)(2) amount of Ecc-treated group is higher than of the control group, which is the same result as obtained through chemical method. The ESR spectrum of O(-.)(2) produced by chloroplasts and mitochondria from tobacco leaves after 2 h and 6 h after Ecc inoculation were observed. In chloroplast experiment, the amplitude of 6 h was larger than of 2 h in Ecc-treated group while it was the same in the control group. ESR spectrum of O(-.)(2) produced by mitochondria was proved to be a same result after a careful comparison, in spite of a greater difference between 2 h and 6 h in control group than chloroplast experiment. The fact that spectra of these two organelles were both synchronous with that of intact leaves implied that these two organelles possibly participated in cellular O(-.)(2) burst. Chloroplasts in the dark showed no ESR spectrum 2 h and 6 h after Ecc inoculation in Ecc-treated group as well as in the control group, indicating that O(-.)(2) in the chloroplast probably originated from the photosynthetic electron transport process.

Chloroplasts↗
PubMed2003

[Expression of gene aiiA carrying the promoter of gene cry3Aa in Bacillus thuringiensis].

N-acyl-homoserine lactones (AHLs), are widely conserved signal molecules present in quorum-sensing systems of many Gram-negative bacteria. AHLs molecules mediate the expression of virulence genes of a range of bacterial pathogens. Recently, it has been reported that AiiA protein, which widely exists in Bacillus species, can inactivate the AHLs by hydrolyzing the lactone bond of AHLs, thus attenuate the diseases caused by the expression of virulence genes of bacterial pathogens. Bacillus thuringiensis, a type of Gram-positive bacteria, has been used extensively as a microbial insecticide in the last few decades. However, most of important insecticidal B. thuringiensis strains have not been exploited for bacterial disease control because they usually do not produce antibiotics that are effective against bacteria and fungi. The discovery of AiiA protein in B. thuringiensis shows the application potential of B. thuringiensis on biocontrol against bacterial diseases. In this study, in order to construct the B. thuringiensis recombinant strain that has high expression of AiiA protein, the promoter of insecticidal crystal protein coding gene cry3Aa of B. thuringiensis was selected. The promoter of gene cry3Aa is a non-sporulation promoter, it promotes the transcription earlier and longer than the promoters of other cry genes. The promoter of AiiA protein coding gene aiiA was replaced with the promoter of gene cry3Aa by overlapping PCR, resulting fusion gene pro3A-aiiA. The gene pro3A-aiiA was inserted into shuttle vector pHT304 at site BamH I / Sph I , resulting recombinant plasmid pBMB686. The plasmid pBMB686 was introduced into B. thuringiensis acrystalliferous strain BMB171, the resulting strain BMB686 had a higher and more stable expression level of protein AiiA comparing with the parental strain BMB171. Furthermore, the strain BMB686 exhibited stronger ability of AHLs inactivation and much more effective restraint to the potato's soft rot disease caused by Erwinia carotovora than those of the parental strain BMB171. From these results, it was concluded that the B. thuringiensis strain harvesting the fusion gene pro3A-aiiA may be utilized in the future to control bacterial diseases which are mediated by the AHL quorum-sensing signals.

Acyl-Butyrolactones↗
PubMedDate not supplied

[Indicator system for studying the lysogenic development of temperate bacteriophage ZF40 Erwinia carotovora].

The indicatory system for studying the lysogenic development of the moderate erwiniophage ZF40 has been created on the basis of the data on the efficiency of inoculation, adsorption of phage particles on a cell, and cooperation between different clear-mutants. The use of the indicatory strains RC5297 and 62A-dl. Derivatives of Erwinia carotovora subsp. carotovora 62A, permitted dividing c-mutants of the phage ZF40 into two types which, in their turn, include 4 groups of complementation (cooperation). An original method has been developed to identify mutants defective in terms of synthesis of the phage repressor. Prerequisites were created for genetic mapping of C-region of the phage ZF40.

Chromosome Mapping↗
PubMedDate not supplied

[The multiple character of mutation of resistance to mitomycin C in Erwinia carotovora subsp. carotovora].

It has been shown that mutants of Erwinia carotovora subsp. carotovora (ECA) resistant to mitomycin C could be characterized by the change of colonies morphology, sensitivity to bacteriocins, and by the change of pathogeneity. It is supposed that mutations responsible for the stability to mitomycin C touch the synthesis of cell membranes components. In some cases MCr-mutations caused cardinal changes--the loss of prototrophy and synthesis of carotinoid pigment. The mutants obtained in this work can be used to study the pathogenic process in Erwinia carotovora. Some of MCr- mutants are the handy indicators of carotovoricins.

Bacteriocins↗
PubMedDate not supplied

[Purification and properties of recombinant Erwinia carotovora L-asparaginase expressed in E.coli cells].

The method of purification Erwinia carotovora recombinant L-asparaginase, expressed in E.coli, including ultrasonic disintegration of biomass, fractionation ammonium sulfate and column chromatography on CM- or SP-Sepharose has been developed. According to SDS-PAAGE the enzyme preparation was homogeneous, its specific activity and yield consist respectively about 620 IU/mg of protein and 75%. Physical-chemical and structural properties of recombinant Erwinia carotovora L-asparaginase are similar to the enzymes from the wild strains Erwinia carotovora and recombinant L-asparaginase Erwinia chrysanthemi.

Asparaginase↗
PubMed2005

[Enhanced resistance to phytopathogenic bacteria in transgenic tobacco plants with synthetic gene of antimicrobial peptide cecropin P1].

Plasmids with a synthetic gene of the mammalian antimicrobial peptide cecropin P1 (cecP1) controlled by the constitutive promoter 35S RNA of cauliflower mosaic virus were constructed. Agrobacterial transformation of tobacco plants was conducted using the obtained recombinant binary vector. The presence of gene cecP1 in the plant genome was confirmed by PCR. The expression of gene cecP1 in transgenic plants was shown by Northern blot analysis. The obtained transgenic plants exhibit enhanced resistance to phytopathogenic bacteria Pseudomonas syringae, P. marginata, and Erwinia carotovora. The ability of transgenic plants to express cecropin P1 was transmitted to the progeny. F1 and F2 plants had the normal phenotype (except for a changed coloration of flowers) and retained the ability to produce normal viable seeds upon self-pollination. Lines of F1 plants with Mendelian segregation of transgenic traits were selected.

Animals↗
PubMedDate not supplied

[Effect of exogenous plasmid R68.45 on productive and lisogenic development of temperate bacteriophage ZF40 Erwinia carotovora].

The Erwinia carotoerora strains bearing exogenous plasmid R68.45 have been obtained by means of transconjugation. Dynamics and frequency characteristics of plasmid transfer to erwinia cells have been studied. Plasmid-phage interrelations have been studied for the first time in E. carotovora. It has been established that the presence of exogenous plasmid R68.45 affects essentially the culture growth parameters and lisogenization of E. carotovora by the wild phage ZF40 and its clear-mutants. The phage infection leads to the exclusion of plasmid R68.45 with different frequency (from 23 to 45% depending on the phage mutant). The presence of plasmid R68.45 in the erwinia cells destabilizes the defective lysogeny in E. carotovora.

Bacteriophages↗
PubMedDate not supplied

[Functional organization of prophage and lysogeny in Erwinia carotovora with participation of a temperate bacteriophage ZF40].

Functional organization of a prophage of the temperate bacteriophage ZF40 of Erwinia carotovora subsp. carotovora which includes its immunity and inducibility as well as its effect on the host phenotype. It was established that the prophage ZF40 forms several different states in E. carotovora which are distinguished by the indices of spontaneous and lysogenic induction. In contrast to other prophages, including the lambdoid ones, the prophage ZF40 is capable to establish cytoplasmic overimmunity which protects the lysogenic system from superinfection by virulent mutants or other homoimmune bacteriophages. An increase of sensitivity of ZF40-lysogens to killing activity of colicino-like carotovoricin (CCTV) and destabilization of defective lysogeny, or resistant MCTV-prophages are related to the phenomenon of the phage lysogenic conversion of E. carotovora.

Bacteriocins↗
PubMedDate not supplied

[Characteristics of lysogenic induction of bacteriocins in thymine mutants of Erwinia carotovora].

Peculiarities of lisogenic induction of bacteriocins in thymine-dependent mutants of Erwinia carotovora subsp. carotovora have been studied. It was shown for the first time that availability of carotovoricins of two (and above) types characterized the defect polylysogeny of strains of different geographic origin. Use of various methods of induction of Thy--mutants or inducing agents of different nature leads to a selective accumulation of carotovoricins of certain types in the cell lysates. Results of the conducted investigations create preconditions for estimating an ecologic part of the defect lysogeny and bacteriocynogenicity for the important phytopathogenic bacterium E. carotovora.

Bacteriocins↗
PubMedDate not supplied

[Oligomerization of L-asparaginase from Erwinia carotovora].

Bacterial L-asparaginases catalyzing hydrolysis of L-asparagine up to L-aspartate and ammonia, are used in medical practice for treatment of acute lymphoblastic leukemia. The long-term therapy with these preparations is accompanied by a number of side effects, which are attributed to glutaminase activity of L-asparaginase. Substrate specificity and activity of L-asparaginases are directly associated with the process of enzyme oligomerization. It is active only in the tetrameric form as the active sites are located in contact areas between monomers. The present work is devoted to homology modeling of spatial structure of L-asparaginase from Erwinia carotovora, the comparative molecular-graphic analysis of subunits interfaces, as well as development of experimental approach for enzyme oligomerization study. L-asparaginase was immobilized on a CM5 chip surface of optical biosensor Biacore 3000 based on the surface plasmon resonance technology. The dissociation process of enzyme tetrameric complexes up to monomers and subsequent oligomerization process have been registered.

Amino Acid Sequence↗
PubMedDate not supplied

[Introduction of transpozon Tn9 to endogenic plasmids of Erwinia carotovora during lysogenization of cells by coliphage P1].

It has been shown that phage P1 of Escherichia coli is able not only to lysogenize the cells of Erwinia carotovora but also to be a source of transpozon Tn9 for mutagenesis of cryptic plasmids of this important phytopathogen. Since the amount of the introduction in one of plasmids pCA25::Tn9 is 3.8 kb, at an average, it is supposed that Tn9 is inherited as a double tandem structure. A convenient method is offered for selecting bacterial clones carrying the plasmid pCA25::Tn9 which is based on counterselection of P1-lysogens at high concentrations of chloramphenicol - 100-120 microg/ml.

Anti-Bacterial Agents↗
PubMed1995

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 and 36 E.c. carotovora serogroups, seven Erw. chrysanthemi biovars, 23 other plant bacterial pathogens and 33 saprophytic bacteria from potato was similar to that of 4G4. Specificity for E.c. atroseptica serogroup I was improved, especially when skimmed milk (Marvel) was used instead of bovine serum albumin as blocking agent. Mabs 1221, 1239 and 4G4 reacted positively with all 22 E.c. atroseptica serogroup I, the dominant E.c. atroseptica serogroup on potato, strains tested and only with two out of five E.c. atroseptica serogroup XXII strains, one E.c. carotovora serogroup XXI strain and one strain of a saprophytic bacterium, Comamonas sp. Essentially similar results were obtained when examined by immunofluorescence. Characterization of the four Mabs showed that they were IgG3 and SDS-PAGE/immunoblot results suggested that they were probably against the O-side chain of bacterial cell wall lipopolysaccharides. In competition ELISA between biotin-labelled and unlabelled Mabs, the competition pattern of the four Mabs was similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[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.

Chromosome Mapping↗
PubMed1995

[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.

Chromosome Mapping↗
PubMedDate not supplied

[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.atroseptica 36ApEA364 cells. At the same time, the efficiency of secretion of heterologous pectate lyases by E.atroseptica 36Ap27-1 cells was lower. The synthesis and secretion of the resident isoenzymes are as efficient as those of the parental cells. The results indicate a high specificity of the pectinase secretory system in Erwinia of different species and, moreover, subspecies.

Cloning, Molecular↗