f Polyacrylamide Gel Electrophoresis of Whole-Cell Proteins of Porcine Strains of Haemophilus

The protein patterns of sodium dodecyl sulfate-solubilized whole cells of porcine strains of Haemophilus were studied by using polyacrylamide gel electrophoresis. The pattern of Haemophilus pleuropneumoniae was very homogenous and was independent of the serological type. At least two different patterns could be distinguished in Haemophilus parasuis, suggesting some heterogeneity in this species. The results were highly reproducible and were not affected by growth conditions. Comparable patterns were obtained after solubilization with sodium taurocholate and sodium carbonate and after ultrasonic treatment, but not after phenol-acetic acid extraction. In addition, we compared porcine strains with human strains (Haemophilus influenzae, Haemophilus parahaemolyticus) and also with some bacteria of the genera Pasteurella, Actinobacillus, Brucella, Moraxella, and Bordetella. The species-specific picture is given mostly by the pattern of a group of proteins with molecular weights just above 68,000 (Haemophilus) and in the region of molecular weights between 23,000 and 40,000 and between 15,000 and 17,000 (Haemophilus, Pasteurella, Actinobacillus). These observations suggest the possible use of this method as an aid in studying the taxonomy of these bacteria.