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Analysis of Plasmids Cloned from a Virulent Avian Escherichia coli and Transformed into Escherichia coli DH5α
Avian Diseases (1996)
  • Richard E. Wooley, University of Georgia
  • Penelope S. Gibbs, University of Georgia
  • Harry W. Dickerson, University of Georgia
  • John Brown, University of Georgia
  • Lisa K. Nolan, North Dakota State University
Three of four plasmids from a virulent wild-type avian Escherichia coli were cloned or transformed into an avirulent laboratory recipient E. coli DH5a and tested for the ability to confer a virulence phenotype. The three plasmids transformed into E. coli DH5a were 5, 6, and 56 kb. A fourth plasmid of 64 kb was not successfully transformed. Parameters used to measure virulence included presence of type 1 pili and a smooth lipopolysaccharide (LPS) layer, motility, production of Colicin V, resistance to host complement, and embryo lethality. The 5-kb plasmid encoded for ampicillin resistance, whereas the 6-kb plasmid encoded for tetracycline resistance. The 56-kb plasmid encoded for streptomycin, sulfisoxazole, and tetracycline resistance. Twelve-day embryos inoculated with 467 colony-forming units of E. coli DH5a containing the 56-kb plasmid had increased death rates (45%) in the embryo lethality assay and a decreased weight of surviving embryos with cranial hemorrhages as compared with embryos inoculated with similar amounts of E. coli DH5a (0%) and phosphate-buffered saline (0%). Embryos inoculated with the wild-type virulent E. coli had 90% deaths. The 56-kb plasmid also had homology with a probe for Colicin V production (cvaC). No differences in LPS layer, complement resistance, motility, Colicin V activity, type 1 pili, cell-free supernatant proteins, or outer membrane proteins were observed in the transformants when compared with nontransformed E. coli DH5cr.
  • avian Escherichia coli,
  • analysis of plasmids,
  • virulence factors,
  • avian colibacillosis
Publication Date
September, 1996
Publisher Statement
Copyright 1996 American Association of Avian Pathologists. Posted with permission.
Citation Information
Richard E. Wooley, Penelope S. Gibbs, Harry W. Dickerson, John Brown, et al.. "Analysis of Plasmids Cloned from a Virulent Avian Escherichia coli and Transformed into Escherichia coli DH5α" Avian Diseases Vol. 40 Iss. 3 (1996)
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