Phenotypic variation in the outer membrane protein composition of Actinobacillus ( Haemophilus) pleuropneumoniae: non-specific effect of exogenous pyridine nucleotide supply

Abstract

Actinobacillus pleuropneumoniae, grown in batch culture, was provided with pyridine nucleotides at concentrations that limited the final growth yield (pyridine nucleotide-deficient cultures) or did not determine the final extent of growth (pyridine nucleotide-sufficient cultures). Sarkosyl-extracted outer membranes from stationary phase, pyridine nucleotide-sufficient organisms contained 23 000 M r and 43 000 M r polypeptides that were absent (23 000 M r) or barely detectable (43 000 M r) in outer membranes from stationary phase, pyridine nucleotide-deficient organisms or exponential phase organisms. When growth ceased due to exhaustion of pyridine nucleotide, the ratio of the major outer membrane polypeptides (31 000, 38 000 and 69 000 M r) was altered, becoming more like the ratio found with exponential phase organisms. Similar results were obtained when growth ceased due to glucose exhaustion at low biomass concentrations demonstrating that diverse nutrient deprivations can induce similar changes in outer membrane protein profile. All of these poly petides were recognized by porcine immune sera indicating their production by A. pleuropneumoniae growing in vivo.