title: Cloning and comparison of heat-stable enterotoxin genes from Escherichia coli strains of bovine, porcine, and avian origins.
abstract: The Ent plasmid encoding Escherichia coli heat-stable enterotoxin (ST) isolated from bovine, porcine, and avian strains were used for the cloning of ST genes. The ST+ DNA regions were finally cloned into pBR322 as the 1.75 kilobases PstI fragment. The electron microscopic analysis of self-annealed molecules indicated that ST+ recombinant plasmid had a stem-loop structure of a size the same as that observed in their wild type Ent plasmids. The stem-loop structures and the restriction enzyme cleavage mappings indicated that 4 kinds of ST genes cloned in this experiment may be identical to Tn1681. The ST production levels of the recombinant plasmids were higher than those of the original plasmids.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle / Q000382:microbiology*; D002645:Chickens / Q000382:microbiology*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004768:Enterotoxins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D007564:Japan; D010957:Plasmids; D013552:Swine / Q000382:microbiology*; D014169:Transformation, Bacterial
chemical_list: D004269:DNA, Bacterial; D004768:Enterotoxins