Characterisation of cell-surface components of Pasteurella haemolytica in relation to virulence

McCluskey, Jacqueline (1994) Characterisation of cell-surface components of Pasteurella haemolytica in relation to virulence. MSc(R) thesis, University of Glasgow.

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This investigation was designed to characterise the surface components, namely the OMPs and LPS, of P. haemolytica and to further the current understanding of the role of these components in the pathogenesis of P. haemolytica infections. Initially, OMP and LPS profiles of 29 P. haemolytica isolates were examined and compared by SDS-PAGE and Western blotting. The isolates used were of known serotype, had a known origin and were from a host whose disease status was known. Eight distinct OMP profiles and three LPS profiles were demonstrated within this population of isolates. An association was found between certain OMP types, LPS types, species of origin and disease status of the host. Thus, the results demonstrated variation in OMP and LPS profiles and provided evidence that these differences may be useful in epidemiological studies of P. haemolytica. A 39.5 kDa outer-membrane protein of P. haemolytica was shown to be heat-modifiable and was identified in all P. haemolytica isolates examined. The protein occurred in one of two molecular-weight forms depending on the solubilisation temperature used, and thus resembled the Omp A protein of E. coli. Western blot analysis, using a rabbit monospecific antiserum to the P. haemolytica 39.5 kDa protein, indicated a serological cross-reactivity with the Omp A protein and N-tenninal amino acid sequence analysis of the P. haemolytica protein also indicated a close homology between these proteins. The property of serum resistance in 22 P. haemolytica isolates and its possible correlation with known surface components was also investigated. Isolates were defined as being serum resistant, partially serum sensitive or serum sensitive, based on the % survivor value obtained in the serum bactericidal assays. Of the 22 isolates examined, 7 isolates proved resistant to serum killing, 6 were highly serum sensitive and the remaining 9 isolates were partially serum sensitive. Although a relationship between smooth-type LPS and serum resistance was identified, there was no correlation of OMP type or capsular type with resistance to serum killing. In vivo studies of P. haemolytica included virulence tests on 7 isolates and in vivo growth in intraperitoneal implant chambers. The virulence tests involved intratracheal inoculation of calves with approximately 10.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Keywords: Microbiology.
Colleges/Schools: College of Medical Veterinary and Life Sciences
Supervisor's Name: Parton, Dr. Roger and Davies, Dr. Robert
Date of Award: 1994
Depositing User: Enlighten Team
Unique ID: glathesis:1994-72861
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 11 Jun 2019 11:06
Last Modified: 29 Jul 2021 11:09

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