title: Cytoplasmic membrane proteins of spectinomycin-susceptible and -resistant strains of Neisseria gonorrhoeae.
abstract: Cytoplasmic membranes were isolated and examined from two spectinomycin-susceptible and three spectinomycin-resistant clinical strains of Neisseria gonorrhoeae. A laboratory-derived spectinomycin-resistant mutant, obtained by serial passage on gradually increasing concentrations of the antibiotic, and a susceptible revertant, spontaneously arising from one of the resistant clinical strains, were also studied. Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis revealed that a major protein, comprising about 7% of total cytoplasmic membrane protein (molecular weight 24,000), was absent in the three clinically isolated spectinomycin-resistant strains. In a revertant, this protein reappeared. During treatment of one of the susceptible strains with spectinomycin, the protein disappeared. However, this correlation was not maintained in the laboratory-derived spectinomycin-resistant mutant. This mutant was of comparable resistant to the clinical isolates, but the 24,000-molecular-weight protein was present in normal quantities. In addition, spectinomycin resistant in clinical isolates was variable compared with stable resistance exhibited by the laboratory-derived mutant. These findings suggested that differences in laboratory-derived versus clinical spectinomycin resistance may be due to different types of resistance mutations.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D004352:Drug Resistance, Microbial; D008565:Membrane Proteins / Q000032:analysis*; D008970:Molecular Weight; D009154:Mutation; D009344:Neisseria gonorrhoeae / Q000032:analysis* / Q000187:drug effects / Q000235:genetics; D000198:Spectinomycin / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D000198:Spectinomycin