Studies on cloning of K99 pilus gene of enterotoxigenic Escherichia coli isolated from calves with diarrhea
1988
Yoon, Y.D. | Kim, J.M. | Ko, G.W. | Joo, Y.S. | Park, J.M. (Rural Development Administration, Anyang (Korea R.). Agricultural Veterinary Research Inst.)
In this studies, the K99 plasmid DNAs from wild strains of enterotoxigenic E. coli from bovine origin were investigated for cloning into E. coli K-12 (HB 101) by using the pBR 322 cloning vector. Of 50 strains of E. coli isolated from calves with diarrhoea, 31 strains (62%) were proved to possess K99 pilus antigen by serological test. All 9 strains possessing K99 pilus antigens were recognized to produce heat-stable enterotoxins (ST) because the ratios of gut weight to remaining body weight were higher than 0.083. Mannose-resistant hemagglutinating activity (MRHA) by using horse red blood cells of 9 strains of E. coli ranged from 1:8 to 1:64 The K99 plasmid DNA purified from strain1074 (80-56) of E. coli was directly transformed into E. coli K-12 (HB101). The plasmids of the transformants harbored about 85 kilobase (Kb) fragment that encoded for K99 pilus antigens. It was proved to possess DNA fragment which was able to synthesize the K99 pilus antigens by MRHA test using horse red blood c
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