title: [Murine model for experimental studies on attenuated mutants of a Pasteurella multocida strain with pathogenicity for the calf. 1. Isolation and biological characterization of streptomycin-dependent mutants (Sm-d) and their examination for immunogenicity in comparison with thermally inactivated pathogens].
abstract: An experimental study was conducted into the immunisation of mice to a strain of Pasteurella multocida with pathogenicity for calf. Here are the results: (a) Stable Sm-d mutants were isolated. (b) The genetic stability of this mutant type was established by unsubstantiable reversion up to the magnitude of 10(-8) or - in cases in which 20 Sm-id revertants maximum occurred in 10(-8) Sm-d germs--by prolongation of the generation period of these suppressor mutants which can be defined also as minus mutants. (c) Stable attenuation of selected Sm-d mutants has been established in mice by intraperitoneal application of 108 germs. (d) Live germs with restricted reproduction exhibited more immunogenicity to thermally inactivated antigen.
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D004195:Disease Models, Animal; D004352:Drug Resistance, Microbial; D005827:Genetics, Microbial; D006358:Hot Temperature; D051379:Mice; D009154:Mutation; D010325:Pasteurella / Q000302:isolation & purification / Q000472:pathogenicity*; D010326:Pasteurella Infections / Q000662:veterinary*; D013307:Streptomycin
chemical_list: D013307:Streptomycin
vernacular_title: Experimentelle Untersuchungen am Mäusemodell mit attenuierten Mutanten eines kälberpathogenen Pasteurella-multocida-Stammes. 1. Isolierung sowie biologische Charakterisierung von streptomyzin-dependenten (Sm-d) Mutanten und deren Prfung auf Immunogenität im Vergleich mit hitzeinaktivierten Keimen