title: Molecular cloning of an Escherichia coli plasmid determinant than encodes for the production of heat-stable enterotoxin.
abstract: A conjugative plasmid, ESF0041 was isolated from an enterotoxigenic strain of Escherichia coli from calves. ESF0041 was found to be 65 x 10(6) daltons in mass of a member of the F incompatibility complex. Acquisition of ESF0041 by E. coli K-12 was invariably associated with the capacity to produce heat-stable (ST) enterotoxin. ESF0041 and pSC101 deoxyribonucleic acids were cleaved with EcoRI, and the fragments were ligated with polynucleotide ligase. Transformation of E. coli K-12 with the ligation mixture led to the isolation of an ST+ clone. Further analysis of the plasmid deoxyribonucleic acid from this clone showed that a structural gene(s) associated with ST biosynthesis had been isolated as a 5.7 x 10(6)-dalton ESF0041 fragment in pSC101. In turn, 5.7 x 10(6)-dalton fragment was ligated to a multicopy COLE1 derivative, RSF2124, so that toxin synthesis was amplified about threefold.
mesh_terms: D004261:DNA Replication; D004768:Enterotoxins / Q000096:biosynthesis*; D004926:Escherichia coli / Q000378:metabolism; D005111:Extrachromosomal Inheritance; D005796:Genes; D010957:Plasmids; D014170:Transformation, Genetic
chemical_list: D004768:Enterotoxins