Development of two novel nontoxic mutants of Escherichia coli heat-labile enterotoxin
نویسندگان
چکیده
منابع مشابه
Heat - labile Enterotoxin of Escherichia coli
Heat-labile enterotoxin (LT) was obtained in large quantities (several-gram amounts) and great purity from Escherichia coli C600 carrying the LT-coding multicopy plasmid EWD299. By growing this strain on a medium that allows high cell densities in the early stationary phase, we increased the net LT production per milliliter by a factor of 200, compared to natural porcine enterotoxigenic E. coli...
متن کاملEscherichia coli Heat - labile Enterotoxin NUCLEOTIDE SEQUENCE
We report the complete DNA sequence of the Escherichia coli elt A gene, which codes for the A subunit of the heat-labile enterotoxin, LT. The amino acid sequence of the LT A subunit has been deduced from the DNA sequence of elt A. The LT A subunit starts with methionine, ends with leucine, and comprises 264 amino acids. The computed molecular weight of LT A is 29,673. The A subunit of cho...
متن کاملCellular location of heat-labile enterotoxin in Escherichia coli.
We demonstrated that both the A and B subunits of heat-labile enterotoxin from Escherichia coli are located in the periplasm. The toxin was shown to form aggregates in Tris-EDTA buffers which are routinely used for isolating membranes. The aggregates pellet upon centrifugation, and this may explain why several previous investigators have concluded that enterotoxin is associated with membranes.
متن کاملBacteriophage conversion of heat-labile enterotoxin in Escherichia coli.
A temperate phage designated obeta1 (omicron beta) was mitomycin C induced and isolated from heat-labile enterotoxin (LT)-producing Escherichia coli E2631-C2. Phage obeta1 infected the nonlysogenic, nontoxigenic, mitomycin C-sensitive strain of E. coli K-12 (CSH38) and converted it to lysogeny and enterotoxigenicity. After the establishment of lysogeny, E. coli CSH38(obeta1) produced produced L...
متن کاملRelease of heat-labile enterotoxin subunits by Escherichia coli.
Most of the heat-labile enterotoxin (LT) synthesized by Escherichia coli is cell associated; however, a small portion of LT (approximately 10%) is released by bacterial cells into the culture supernatant. The LT subunit B (LT-B) produced by a cloned LT-B gene (tox B) was released in amounts equal to the parent LT release. In contrast, no release of LT subunit A (LT-A) or its smaller derivatives...
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ژورنال
عنوان ژورنال: Experimental & Molecular Medicine
سال: 1999
ISSN: 2092-6413
DOI: 10.1038/emm.1999.17