title: Neuraminidase (sialidase) activity of Haemophilus parasuis.
abstract: Neuraminidase (sialidase), a potential virulence factor in bacteria, was demonstrated in Haemophilus parasuis, an invasive swine pathogen, but not in four other pathogens of the Pasteurellaceae family: H. influenzae, H. somnus, H. paragallinarum, or Actinobacillus pleuropneumoniae. H. parasuis neuraminidase had an acidic pH optimum and a specificity for several substrates also cleaved by other bacterial neuraminidases. Similar to the neuraminidase of Pasteurella multocida, H. parasuis neuraminidase was cell associated and did not require divalent cations for activity. Exogenous sialic acid added to growth medium of H. parasuis was cleared after a lag of about 10 h and these cultures grew to a greater final density than cultures without added sialic acid, indicating that exogenous sialic acid is metabolized. The role of sialidase in providing nutrients to H. parasuis may be an important factor in its obligate parasitism.
authors.affiliation: Department of Veterinary Pathobiology MC-002, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA. clichten@uiuc.edu
authors.forename: C A
authors.initials: CA
authors.lastname: Lichtensteiger
authors.forename: E R
authors.initials: ER
authors.lastname: Vimr
mesh_terms: D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006190:Haemophilus / Q000201:enzymology* / Q000254:growth & development; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine
chemical_list: D002413:Cations, Divalent; D004791:Enzyme Inhibitors; D004533:Egtazic Acid; D004492:Edetic Acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid