title: Differences in protein expression of Haemophilus somnus grown under conditions of iron-restriction.
abstract: Outer membrane protein profiles were compared in 14 H. somnus strains isolated from brain and lung lesions as well as from the genital tract of asymptomatic carriers during in vitro growth under iron-restricted conditions. Ethylenediamine-di-O-hydroxyphenyl acetic acid (EDDA) was used to obtain iron-restricted conditions in media used for this study. The outer membrane protein profiles were studied by the discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoretic system (SDS-PAGE), and the proteins were stained with silver or transferred to nitrocellulose sheets and western blots conducted. Growth under iron-restricted conditions resulted in the induction of outer membrane proteins in most H. somnus strains examined. Studies also indicated differences among H. somnus strains in the number of induced proteins and their molecular weights but the results did not indicate a specific relationship between these strain-dependent differences and tissue trophism. Western blot analysis revealed a high degree of immunological relatedness among strains of H. somnus in their iron-regulated proteins. However, hyperimmune serum used in these assays failed to recognize certain iron-regulated proteins expressed by some H. somnus strains, a finding which may have important implications for the induction of protective immunity in cattle against this bovine pathogen.
authors.affiliation: Department of Pathology and Epidemiology, National Veterinary Laboratory, Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Wedderkopp
authors.forename: S V
authors.initials: SV
authors.lastname: Primal
authors.forename: S
authors.initials: S
authors.lastname: Silva
authors.forename: P B
authors.initials: PB
authors.lastname: Little
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis* / Q000276:immunology; D015153:Blotting, Western; D002417:Cattle; D003470:Culture Media; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D006190:Haemophilus / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D007106:Immune Sera / Q000276:immunology; D005779:Immunodiffusion; D007501:Iron / Q000378:metabolism*; D014774:Virulence / Q000187:drug effects
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003470:Culture Media; D007106:Immune Sera; D007501:Iron