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At least 19 recordsLinked to original sources
PubMed1979

[Acceptance and transfer of plasmid Rts1 by bacteria of the genus Erwinia].

The ability of 13 Erwinia strains to accept, to inherit and to transmit the Rts1 factor by conjugation was studied. 11 strains accepted the Rts1 factor from Escherichia coli K-12 CSH-2 with the frequency of about 10(-7)--10(-3). The Rts1 factor was genetically stable in the Erwinia cells and was not eliminated by acriflavine and under the temperature of 37 and 42 degrees C. All the R+ exconjugants were characterized with more high degree of the resistance of kanamycin than E. coli cells harbouring the same R factor. Erwinia strains harbouring the Rts1 plasmid transferred it by conjugation into homologic (Erwinia) and heterologic (E. coli) bacteria. The study of kinetics of the transfer of the Rts1 factor in different mating systems showed that the transfer of this plasmid from R+ Erwinia into R- Erwinia and R- E. coli--in the liquid medium. It is concluded that Erwinia can be the host and the donor of the Rts1 factor.

Conjugation, Genetic↗
PubMed1978

[Transmission of F'lac plasmid from Escherichia coli K-12 to bacteria of the genus Erwinia].

The F'lac plasmid was transferred by conjugation from Escherichia coli K-12 W1655 to 21 lac- strains of Erwinia spp. (5.2 . 10(-6) to 6.8 . 10(-2) lac+ exconjugants per donor cell). Erw. herbicola and Erw. chrysanthemi were the better recipients than others. The degree of the stability of lac+ genes in Erwinia exconjugants depends on the strains. Stable exconjugants of Erwinia, which harbored F'lac plasmid, were able to utilize lactose, to transfer lac genes by conjugation to Erwinia spp. and E. coli, and were sensitive to the F-specific phages f1, f2, Qbeta. The F'lac plasmid was eliminated from the exconjugants by the treatment with acridine orange, which indicates that this genetic element is not integrated into the Erwinia chromosome.

Conjugation, Genetic↗
PubMed1976

Polygalacturonic acid trans-eliminase in the osmotic shock fluid of Erwinia rubrifaciens: characterization of the purified enzyme and its effect on plant cells.

An endopolygalacturonic acid trans-eliminase (EC 4.2.2.2), released by osmotic shock of Erwinia rubrifaciens cells, has been purified to near homogeneity (3, 100-fold) by column chromatography on diethylaminoethyl-cellulose, phosphocellulose, and hydroxyapatite-cellulose followed by isoelectric focusing. It has a molecular weight of 41,000, s20,w of 3.09S, an isoelectric point of pH 6.25, pH optimum of 9.5, and a temperature optimum of 37 C and requires Ca2+ with an optimum concentration of 0.5 to 1.0 mM. Mg2+ could not substitute for Ca2+. Tyrosinyl residues seem essential for enzyme catalysis based on rapid inactivation by tetranitromethane. The enzyme prefers unmethylated polygalacturonic acid as the substrate, cleaving alpha-1,4-glycosidic linkages randomly to form unsaturated galacturonides at a Vmax of 1,166 mumol of product/min per mg of protein and a Km of 5 mg of polygalacturonic acid per ml. Over 90% of the enzyme activity is released from osmotically shocked E. rubrifaciens cells. Unlike E. rubrifaciens, trans-eliminase is not released from Erwinia carotovora cells by osmotic shock treatment, but enzyme activity is detected in the culture medium. The release of the enzyme is reduced fivefold by the addition of dibutyryl cyclic adenosine 5'-monophosphate. The hypersensitive reaction in tobacco leaves was induced within 60 min after injection of less than 1 mug of purified E. rubrifaciens trans-eliminase. Single cells of tobacco in suspension culture are readily killed by the enzyme, whereas tobacco protoplasts remain unaffected when treated in the same manner. These results indicate that endopolygalacturonic acid trans-eliminase is a constitutive enzyme possibly located in the periplasmic space of the E. rubrifaciens cell and releases enzyme into the culture medium in the presence of substrate. The release of the enzyme in tobacco tissue and the trans-eliminative cleavage of plant cell wall components may be steps leading to hypersensitivity of the tobacco tissue.

Calcium↗
PubMed1977

Application and standardization of various procedures for inoculation of maize by Erwinia carotovora f. sp. zeae.

Hypodermic syringe and toothpick methods were best for evaluating pathogenicity of the maize plant against Erwinia carotovora f. sp. zeae, both in glass house and in the field. The portion of the stalk above the ground was best suited for reproducing the disease symptoms. Leaf and leaf whorl did not show any rotting hero. Seed inoculation showed least mortality percentage. Root inoculation was suitable only for young seedlings. Cotyledons, as an organ for inoculation for getting best reproducible infection, were not at all suitable.

Bacteriological Techniques↗
PubMed1978

Serologic studies of the maize stalk rot pathogen Erwinia carotovora f. sp. zeae.

With the help of serological techniques, namely microprecipitin, agglutination, and gel diffusion, sixteen isolates of maize stalk rot pathogen were proved to be identical. Serological techniques have thus been utilized as an additional tool for identifying the pathogen Erwinia carotovora f. sp. zea. It was also established that the pathogen does not perpetuate in the seed, either externally of internally. It could, however, be found through serological tests that infected ears carried the pathogen and transmitted it as a contaminant to the healthy seeds.

Agglutination Tests↗
PubMed1979

Production of cellulase (Cx) by different species of Erwinia.

The tested isolates of Erwinia chrysanthemi (corn pathotype) and E. carotovora constitutively produce high levels of cellulase(s) (Cx) in presence or absence of carboxymethyl-cellulose (CMC) as substrate in the medium. The tested isolates of E. atroseptica produced high levels of cellulase when grown in presence of both carboxymethyl-cellulose (CMC) and sucrose, low levels in presence of carboxymethyl-cellulose alone, and traces of cellulase(s) in presence of sucrose alone. The activity of cellulase(s), present in culture supernatants of E. chrysanthemi (corn pathotype) and E. carotovora, occurred in a broad range of pH value (2.2--9) with an optimum pH ranging from pH 4 to 7. However, the activity of cellulase(s), present in culture supernatant of E. atroseptica, occurred in a narrow range of pH value (3--7) with an optimum of about pH 5.

Carboxymethylcellulose Sodium↗
PubMed1975

Partial purification and properties of a beta-glucosidase from Erwinia herbicola Y46.

A constitutive beta-glucosidase of Erwinia herbicola Y46 was studied as a prerequisite to an assessment of its significance in the release of bacteriotoxic aglycones from plant beta-glucosides, and the possible effects of the aglycones on the course of such plant diseases as "fire-blight". The enzyme was purified 86.5-fold from crude extracts of cells grown on yeast beef broth. Ammonium sulfate precipitation, DEAE-cellulose fractionation, and gel filtration through Sephadex G-100 resulted in a preparation having one peak of activity on isoelectrofocussing, on gel filtration through Sephadex G-200, and on polyacrylamide gel electrophoresis. The latter techniques demonstrated, in addition to the major protein band associated with activity, a single minor impurity. The enzyme was active against p-nitrophenyl-beta-glucoside (p-NPG) and phloridzin, but showed only very slight activity against salicin and arbutin, and no detectable activity against beta-methyl-D-glucoside, cellobiose, lactose, and esculin. The production of beta-glucosidase was maximum at the late log phase of growth on yeast beef broth medium and declined somewhat thereafter. The incorporation of inducers (carbohydrates) in defined basal medium resulted in only small variations in specific activity in the resulting cells; The activity (p-NPG substrate) was not inhibited by D-glucose, phloretin, esculin, salicin, arbutin, lactose, or cellobiose, but was slightly inhibited by 1.0 mM phloridzin. Slight inhibition was observed in the presence of sulfhydryl reagents (iodoacetamide, p-chloromercuribenzoate), but sodium azide, ethylene-diaminetetraacetic acid, Cu2+, and Zn2+ ions produced no effect. The activity was stable, in both crude and purified preparations, over the pH ranges 6.0-7.5 (100% activity) and 4.5-greater than 8.5 (50% activity). The enzyme retained 80% activity after 30 min at 50 degrees C, but only 25% after 30 min at 60 degrees C. The enzyme had a mean K-m value (phloridzin) of 1.35 times 10-4 M, an isoelectric point of 4.75, a molecular weight, determined by Sephadex G-200 gel filtration, of about 122 000, and an optimum pH for activity of 6.5-7.0.

Ammonium Sulfate↗
PubMed1975

The isolation and characterization of a temperate phage, Y46/(E2), from Erwinia herbicola Y40.

A temperate phage was induced from exponential phase cells of Erwinia herbicola Y46 by treatment with mitomycin C. The phage was purified by single plaque isolation, and produced in bulk by successive cultivation in young cultures of E. herbicola Y 178. Phages were concentrated from culture filtrates by rate zonal centrifugation and resuspension in 0.02 M Tris buffer, pH 7.2, twice, yielding suspensions of about 5 times 10(11) PFU/ml. Purification was achieved by centrifugation in buffered sucrose solutions. The band at the 30/40% sucrose interface yielded intact particles having regular hexagonal heads and lonb contractile tails, with base plates. Fibers were not seen. The mean dimensions were head, 51 nm; neck length, 11 nm; overall tail length, extended, 98 nm and contracted, 75 nm; diameter of tail sheath, 24 nm. The phage was stable from pH 4.0 to 11.0, but unstable at pH 3.0, the response being independent of the suspending medium used. At pH 3.0, a survival curve having biphasic appearance was observed, which was not due to a mixed population of phages. Stability to heat was good up to 45 degrees C, above which a logarithmic decline with temperature increase occurred. The average inactivation rate constant at 50 degrees C and pH 6.8 was 0.15 min-1. Adsorption to E. herbicola Y 178 cells exhibited first-order kinetics, the adsorption rate constant being 2.5 times 10(-10) ml/min. One-step growth-curve experiments indicated a burst size of 35-40, and a minimum latent period of 80 min. Probit analysis gave a mean latent period of 140 min (SD 25). The phage caused lysis of only E. herbicola strains Y178 and Y186.

Adsorption↗
PubMed1977

Transfer of episome F'lac+ and chromosomal trp+ genes from Erwinia amylovora to Salmonella typhimurium.

The F'lac+ episome of Escherichia coli origin was transferred by conjugation with frequencies of 10(-7) to 10(-5) from Erwinia amylovora to 14 out of 15 Salmonella typhimurium trp female parents. The chromosomal trp+ genes were transferred with frequencies of 10(-7) to 10(-6) only to one trpB and 2 trpD female parents, which have a point mutation in the 2nd and fourth structural genes, respectively, of the tryptophan operon. The transferred male trp+ genes became integrated at the selected sites of the S. tryphimurium chromosome. The resulting Trp+ hybrids were phenotypically stable, lacked a cryptic trp allele selected against in the female parent, had high genetic homology values in the tryptophan region, and showed biochemical reactions and pathogenicity typical of S. typhimurium.

Animals↗
PubMed1977

Toxic and immunodepressive effects of L-asparaginase from E. coli and from Erwinia carotovora following chronic administration in rats.

The effects of the administration of L-asparaginase from E. coli and Erwinia carotovora were studied in rats treated for 90 days with 800 or 3200 IU/kg body weight. The studies included overall toxicity on the liver, pancreas, and enteric mucosa as evaluated by both opitcal and electron microscopic examination, biochemical findings, behaviour of IgM-hemolysin producing cells, and antias-paraginase antibody production. The toxic effect and the immunodepressive activity appeared rather early, tending later to decrease. No sex correlation or clear cut dose correlation were observed. However, slight differences in toxicity between the two types of L-ASN-ase were present.

Animals↗
PubMed1978

[F'ColVColBtrpcys plasmid in Erwinia aroideae].

Erwinia aroideae carries a cryptic plasmid with 30 S sedimentation coefficient. Plasmid F'ColVColBtrpcys does not dissociate in E. aroideae and is replicated under stringent control since the number of plasmid copies per chromosome does not exceed one. The behaviour of F'ColVColBtrpcys plasmid in E. aroideae is characterized by (1) instability observed at both spontaneous and after EB treatment, (2) depression of plasmid genes that determine colicin synthesis.

Colicins↗
PubMed1979

Improvement in the therapeutic, immunological, and clearance properties of Escherichia coli and Erwinia carotovora L-asparaginases by attachment of poly-DL-alanyl peptides.

The chemical modification of both Escherichia coli and Erwinia carotovora asparaginases by a DL-alanine-N-carboxyanhydride polymerization technique produced modified enzymes which had greater protease stability, retained most of their catalytic activity, and demonstrated a 7- to 10-fold prolongation in plasma clearance properties in normal mice and rats. Concomitantly, plasma substrate depletion was also extended 5 to 13 days longer for the modified as compared with the native enzymes. For preparations of modified enzymes with plasma half-lives longer than 24 hr, the therapeutic activity was superior to that of the native enzymes. In addition, the modified E. coli preparations were less immunogenic in mice than was the native enzyme, and they cross-reacted with antibodies developed to the native enzyme to a 300-fold lesser degree, such that the modified enzyme still showed prolonged clearance in an animal which had been immunized previously to the native enzyme. The native enzyme was immediately cleared from the plasma of such immune animals, although hyperimmune animals would rapidly clear both the native and modified enzymes. Similarly, the modified E. carotovora enzyme would cross-react to a 500-fold lesser degree with antibodies developed against the native E. carotovora enzyme.

Alanine↗