Identification of the capsular polysaccharides of Type D and F Pasteurella multocida asunmodified heparin and chondroitin, respectively

摘要

Pasteurella multocida is a pathogenic Gram-negative bacterial species that infects a wide variety of animals and humans. A notable morphological feature of many isolatesis the extracellular capsule. The ability to remove the capasule by treatment with certain glycosidases has been utilized to discern various capsular types called A, D and F. Based on this preliminary evidence, these microbes have capsules made of glycosaminoglycans, linear polysaccharides composed of repeating disaccharide units containing an amino sugar. Glycosaminoglycans are also abundant components of the vertebrate extracellular matrix. It has been shown previously that the major Type A capsular material was hyaluronan (hyaluronic acid). We report that the Type D polymer is an unmodified heparin (N-acetylheparosan) with a ->4)-beta-D-Glcp-UA-(1->4)-alpha-D-Glcp-NAc-(1-> repeating unit and the Type F polymer is an unmodified chondrotin with a ->4)-beta-D-Glcp-UA-(1->3)-beta-D-Gal-NAc-(1-> repeating unit. The monosaccharide compositions, disaccharide profiles, and ~1H NMR analyses are considered with these identifications. The molecular size of the Pasteurella polymers is approximately 10-300 kDa as determined by gel electrophoresis and multi-angle laser light scattering this size is much greater than the 10-30 kDa sizeof the analogous polymers isolated from animal tisues. The glycosaminoglycan capsular polymers are relatively non-immunogenic virulence factors that enhance microbial pathogenicity.