Article Abstract:
Three methods for the construction of Escherichia coli K-12 strains with the ability to use sucrose as the sole carbon source were developed. In the first method, the sucrose utilization system (Scr+) from E. coli B-62 was cloned to pBR322 and transformed into K-12, resulting in sucrase activity corresponding to a gene dosage effect. In the second method, the gene coding for Scr+ was substituted for the glyA region of pBR322, and transformed into K-12, resulting in homologous recombination of the Scr+ gene. Lastly, the low- copy-number plasmid RP4 was used as a cloning vector. The effectivity of gene transfers were assessed by tryptophan production through sucrose.
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Article Abstract:
A green fluorescent protein-expressing Escherichia coli O157:H7 strain has been used to monitor the behavior of the pathogen in ground beef stored aerobically from freshness to spoilage at 2 and 10 degrees Celsius. Effects of sodium salts of lactate, diacetate and buffered citrate were and combinations were studied. The pathogen was resistant to salts tested. It was confirmed that refrigerated meat contaminated with the pathogen does not stop being hazardous.
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Article Abstract:
Research describes generation of monoclonal antibody 12F5 that reacts specifically with Eschrechia coli O26 isolates and Mab 15C4 reacting with E.Coli O111 strains. Specificity of the monoclonal antibodies is confirmed by their reactivity towards O-antigen of the lipopolysaccharide.
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