Pasteurella multocida is a Gram-negative multi-species pathogen and the causative agent of fowl cholera, a serious disease of poultry which can present in both acute and chronic forms. The major outer membrane component lipopolysaccharide (LPS) is both an important virulence factor and a major immunogen. Our previous studies have determined the LPS structures expressed by different P. multocida strains and revealed that a number of strains belonging to different serovars contain the same LPS biosynthesis locus but express different LPS structures due to mutations within glycosyltransferase genes. In this study we report the full LPS structure of the serovar 4 type strain, P1662, and reveal that it shares the same LPS outer core biosynthesis locus, L3, with the serovar 3 strains, P1059 and Pm70. Using directed mutagenesis, the role of each glycosyltransferase gene in LPS outer core assembly has been determined. LPS structural analysis of 23 Australian field isolates that contain the L3 locus reveal that at least six different LPS outer core structures can be produced as a result of mutations within the LPS glycosyltransferase genes. Moreover, some field isolates produce multiple but related LPS glycoforms simultaneously and three LPS outer core structures are remarkably similar to the globo series of vertebrate glycosphingolipids. Our in-depth analysis showing the genetics and full range of P. multocida lipopolysaccharide structures will facilitate the improvement of typing systems and the prediction of the protective efficacy of vaccines.
Lipopolysaccharide, biosynthesis, genetics, virulence factor, Pasteurella multocida, typing
NCBI PubMed ID: 23974032Publication DOI: 10.1128/JB.00779-13Journal NLM ID: 2985120RPublisher: American Society for Microbiology
Correspondence: john.boyce@monash.edu
Institutions: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Melbourne, Australia
Methods: 13C NMR, 1H NMR, methylation, GLC-MS, de-O-acylation, SDS-PAGE, DNA techniques, 31P NMR, ESI-MS, CE-MS, sugar analyis
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