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PubMedDate not supplied

Negligible hemostatic toxicity of intermediate-dose Erwinase in adult patients with acute lymphoblastic leukemia: preliminary data.

The hemostatic toxicity of low dose L-asparaginase from Erwinia carotovora (Erwinase) has been reported to be negligible in adult patients with acute lymphoblastic leukemia (ALL); conversely, no consistent data have been obtained when Erwinase is administered at intermediate doses. We report preliminary clinical and laboratory hemostatic data from 10 adult patients with ALL treated during induction phase with intermediate doses of Erwinase (20,000 IU/m2s.c. every other day, for a total of six administrations). No thrombotic or hemorrhagic events were registered and the mean values of PT, aPTT, fibrinogen, antithrombin and D-dimer did not change during treatment. Only one patient showed a decrease of antithrombin (48% on day 8) requiring temporary suspension of Erwinase therapy. These data suggest that intermediate doses of Erwinase also have negligible hemostatic toxicity in adult patients with ALL.

Adolescent↗
PubMed1994

Thin film formation by rough form lipopolysaccharide and interaction with cationic antibiotic polymyxin B.

A monolayer film of the rough form of lipopolysaccharide (LPS) from Erwinia carotovora at an air-water interface was transferred onto solid substrates to form a multilayer film. The LPS was deposited on hydrophobic graphite as well as on hydrophilic platinum plates. The thickness of the LPS film prepared by a single dipping and removal of the graphite was estimated at 2.7 nm by atomic force microscopy. The repeated dipping of the platinum plate indicated early saturation with reduced subsequent absorption from the pure water subphase, while successive transfers of the LPS were observed from a 2.0 mM MgCl2 solution. The LPS film on the quartz crystal microbalance (QCM) interacted with cationic antibiotic polymyxin B in the solution and exhibited a downward shift of resonant frequency and resistance in proportion to its concentration. The resonant resistance change against the resonant frequency axis was parallel in this interaction. The absorption of the antibiotic on the LPS film prepared in the presence of MgCl2 indicated an increase in mass, but little change in viscoelasticity. A multilayer film of LPS on the QCM was found suitable for subsequent characterizations.

Absorption↗
PubMedDate not supplied

Fermentative production and isolation of L-asparaginase from Erwinia carotovora, EC-113.

L-Asparaginase, an enzyme-drug used for the treatment of acute lymphoblastic leukemia was isolated from Erwinia carotovora. The effects of different carbon and nitrogen sources on the fermentative production of the enzyme were studied. Lactose, monosodium glutamate, corn steep liquor, tryptone and yeast extract showed significant stimulation of the production. When L-asparagine (0.2%), a substrate of the enzyme was added to a fermentation medium, a mutant strain EC-113 exhibited 6 times higher production indicating a distinct induction. The enzyme was extracted from the cells and purified about 30 fold to apparent homogeneity employing polyacrylamide gel electrophoresis. The methods used in sequence were DEAE cellulose chromatography, sephadex G-200 gel filtration, hydroxylapatite ion-exchange and affinity chromatography on sepharose CL-6B. The recovery of enzyme was 60%. The purified enzyme showed optimal pH at 8.0 and optimal temperature at 50 degrees C. The Km value of purified enzyme was 1.8 x 10(-5) M. LD50 of purified enzyme in mice by intravenous route was 4,80,000 IU/Kg and repeated treatment at 20,000 IU/Kg by intravenous route did not elicit bone marrow depression or damage to intestinal mucosa. The plasma half life was 14-24 hours and clearance time was 4-5 hours. Purified enzyme shows significant antitumor activity on experimental animal models.

Asparaginase↗
PubMedDate not supplied

[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 unable to efficiently secrete the enzymes into the cultural medium. Synthesis and secretion of the native pectate lyases by Erwinia atroseptica harboring the plasmid were as efficient as by the parental cells. The obtained results suggest the high specificity of pectate lyase secretory systems of kindred Erwinias.

Cloning, Molecular↗
PubMed1996

Analysis of bacterial carbapenem antibiotic production genes reveals a novel beta-lactam biosynthesis pathway.

Carbapenems are beta-lactam antibiotics which have an increasing utility in chemotherapy, particularly for nosocomial, multidrug-resistant infections. Strain GS101 of the bacterial phytopathogen, Erwinia carotovora, makes the simple beta-lactam antibiotic, 1-carbapen-2-em-3-carboxylic acid. We have mapped and sequenced the Erwinia genes encoding carbapenem production and have cloned these genes into Escherichia coli where we have reconstituted, for the first time, functional expression of the beta-lactam in a heterologous host. The carbapenem synthesis gene products are unrelated to enzymes involved in the synthesis of the so-called sulphur-containing beta-lactams, namely penicillins, cephamycins and cephalosporins. However, two of the carbapenem biosynthesis genes, carA and carC, encode proteins which show significant homology with proteins encoded by the Streptomyces clavuligerus gene cluster responsible for the production of the beta-lactamase inhibitor, clavulanic acid. These homologies, and some similarities in genetic organization between the clusters, suggest an evolutionary relatedness between some of the genes encoding production of the antibiotic and the beta-lactamase inhibitor. Our observation are consistent with the evolution of a second major biosynthetic route to the production of beta-lactam-ring-containing antibiotics.

Amino Acid Sequence↗
PubMedDate not supplied

Antibiotics and garlic clove extract--inhibitory agents of cell wall degrading enzymes.

Four antibiotics were tested against Erwinia causing soft rot of onion (Allium cepa var. aggregatum) of which streptomycin sulphate 90% and tetracycline hydrochloride 10% (streptocycline) recorded the maximum inhibition zone of 27.66 mm. In the enzyme studies the maximum inhibition of pectinlyase (PL), polygalacturonase (PG) and protopectinase production was recorded by the same antibiotic. The antibiotics have a significant influence on the production and activity of cell wall degrading enzymes produced by the plant pathogenic microorganisms. Garlic clove extract was equally effective in inhibiting the growth and enzyme production.

Anti-Bacterial Agents↗
PubMed1998

Cloning and sequencing of the celA gene encoding CMCase of Erwinia carotovora subsp. carotovora LY34.

The phytopathogenic Erwinia carotovora subsp. carotovora LY34 secretes multiple isozymes of the plant cell wall-disintegrating enzyme, endoglucanases. Genomic DNA from Ecc LY34 was digested with Sau3AI and ligated into the BamHI site of pBluescript II SK+. One of the E. coli clones containing a Sau3AI fragment of Ecc genomic DNA hydrolyzed carboxymethyl cellulose and was shown to contain the 2.2 kb BamHI restriction fragment, which was subcloned to generate pLYCA100 named as celA. The structural organization of a celA gene encoding 387 amino acids consists of an open reading frame (ORF) of 1161 bp starting with an ATG start codon and followed by a TAA stop codon. CelA protein contained a typical catalytic domain, interdomain, cellulose binding domain, and prokaryotic signal peptide of 32 amino acids. Since the deduced amino acid sequences of CelA protein was very similar to those of CelV of Erwinia carotovora subsp. carotovora SCC3193 enzyme and to those of CelN of Erwinia atroceptica enzyme, it belongs to the cellulase family 5. The apparent molecular mass of CelA protein was calculated to be 39 kDa by carboxymethylcellulose-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (CMC-SDS-PAGE). Activity staining of carboxymethyl cellulase (CMCase) in sodium dodecyl sulfate polyacrylamide gel containing 0.1% CMC revealed that the cloned isozyme comigrated with a corresponding isozyme produced by Ecc LY34. The CelA had a calculated pI of 5.42. The optimum pH was 7 and the optimum temperature was about 45 degrees C.

Amino Acid Sequence↗
PubMed1998

Cloning and characterization of a CMCase gene, celB, of Erwinia carotovora subsp. carotovora LY34 and its comparison to celA.

The phytopathogenic Erwinia carotovora subsp. carotovora (Ecc) LY34 secretes multiple isozymes of the plant cell wall-disintegrating enzyme endoglucanase. We isolated a second cel gene encoding CMCase in Ecc LY34. A 3.7 kb fragment was subcloned to generate pLYCB100 (celB). The structural organization of the celB gene consists of an open reading frame (ORF) of 792 bp encoding 264 264 amino acid residues with a calculated molecular weight of 29,890 Da The predicted amino acid sequence of CelB is very similar to that of CelS of another Ecc strain, SCRI193, but completely different from that of the CelA of Ecc LY34. It belongs to the glycosyl hydrolase family 12 based on amino acid sequence similarities. It is optimally active at pH 6.8 with an optimal temperature of about 50 degrees C. The CMCase activity of CelB is about 60% of that of CelA.

Amino Acid Sequence↗
PubMed1998

Bacillus subtilis BS 107 as an antagonist of potato blackleg and soft rot bacteria.

Antimicrobial substances were produced by Bacillus subtilis BS 107 in a defined medium and isolated from culture filtrate by precipitation at pH 2.5. Active fractions were extracted in ethyl acetate, acetone, and 80% ethanol and purified by thin-layer chromatography (TLC) on silica gel plates developed with an ethanol-water mixture (2:1, v/v). In each case, a band with a Rf of 0.75 formed an inhibitory zone when the TLC plates were placed in contact with agar seeded with test cultures of the Erwinia spp. The antibiotic was released into the culture medium during early stages of growth of Bacillus subtilis BS 107 but higher amounts were released in older cultures. The antibiotic was resistant to the action of nucleases, proteases, and lipase. It was stable when autoclaved twice for 35 min at 2 atm (1 atm = 101.325 kPa) in acidic, neutral, and alkaline solutions. It remained active over the pH range of 1-14 during 1 month of observation and exhibited no loss of antimicrobial activity when stored at 4 degrees C for over 1 year. Bacillus subtilis BS 107 showed activity in vitro and in vivo against Erwinia carotovora subsp. atroseptica and Erwinia carotovora subsp. carotovora, the causal agents of potato blackleg and tuber soft rot. The application of an antagonist or its antibiotic to cut potato tissues prevented or reduced symptoms of the diseases. The antibiotic was active in vitro against a broad spectrum of bacterial and fungal species.

Anti-Bacterial Agents↗