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Phenotypic Expression Of Recombinant Plasmids Pkt107 And Phk11 In An Avirulent Avian Escherichia Coli, Richard E. Wooley, Lisa K. Nolan, John Brown, Penelope S. Gibbs, Denise I. Bounous
Phenotypic Expression Of Recombinant Plasmids Pkt107 And Phk11 In An Avirulent Avian Escherichia Coli, Richard E. Wooley, Lisa K. Nolan, John Brown, Penelope S. Gibbs, Denise I. Bounous
Lisa K. Nolan
An avirulent wild-type avian Escherichia coli strain (Av) was electrotransformed with plasmids coding for complement resistance (pKT107) and Colicin V (ColV) production (pHK11) in order to study the effects of complement resistance and ColV production on virulence. Transformants were also compared with the wild type for embryo lethality, uptake by macrophages, motility, growth rate, plasmid content, and hemolysis. Growth rates and complement resistance patterns of strain Av and transformant Av+pHK1 1 were similar, but Av+pHK11 caused a significantly greater number of deaths in embryos and acquired motility. Transformant Av+pKT107 had a lower rate of phagocytosis, a slower growth rate, and …
Characterization Of An Avirulent Mutant Of A Virulent Avian Escherichia Coli Isolate, Lisa K. Nolan, Richard E. Wooley, Catherine W. Giddings, John Brown
Characterization Of An Avirulent Mutant Of A Virulent Avian Escherichia Coli Isolate, Lisa K. Nolan, Richard E. Wooley, Catherine W. Giddings, John Brown
Lisa K. Nolan
A virulent, complement-resistant avian Escherichia co/lisolate and its avirulent, complement-sensitive, transposon-insertion mutant were compared for the purpose of revealing structures associated with complement resistance. Both had a smooth lipopolysaccharide layer, contained traT, and lacked a capsule, but the mutant possessed a 16.2-kilodalton outer-membrane protein (OMP) not present in the wild-type. This protein may be the product of a coding region interrupted by transposon insertion. Such results suggest that an OMP greater than 16.2 kilodaltons in size may be responsible for the complement resistance and virulence of this wild-type E. coli.
Effect Of Normal Intestinal Flora Of Chickens On Colonization By Virulent Colicin V-Producing, Avirulent, And Mutant Colicin V-Producing Avian Escherichia Coli, Richard E. Wooley, John Brown, Penelope S. Gibbs, Lisa K. Nolan, Kathy R. Turner
Effect Of Normal Intestinal Flora Of Chickens On Colonization By Virulent Colicin V-Producing, Avirulent, And Mutant Colicin V-Producing Avian Escherichia Coli, Richard E. Wooley, John Brown, Penelope S. Gibbs, Lisa K. Nolan, Kathy R. Turner
Lisa K. Nolan
Colonization of the intestinal tracts of newly hatched chicks with Escherichia coli was attempted by swabbing test organisms onto the air-shell of 19-day-old embryos. Test organisms consisted of two virulent E. coli isolates, one avirulent isolate, and one laboratory-derived mutant of the avirulent isolate carrying a recombinant plasmid coding for Colicin V production. Chicks were cultured weekly for 3 weeks for total E. coliand for the test organisms using selective media. Control chicks were sampled on weeks 1 and 5, and the normal E. coli intestinal microflora were examined for the production of colicins. The two virulent E. coli isolates …