Comparison of the Pasteurella haemolytica A1 envelope proteins obtained by two cell disruption methods

The French pressure cell and sonication methods of bacterial cell disruption were compared for the evaluation of surface proteins from Pasteurella haemolytica A1. Several protein bands were quantitatively different when compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and densitometry. With densitometry, sonicated preparations had higher concentrations of the 102-, 83-, 50-, 38-, and 30-kilodalton (kDa) proteins; French pressure cell preparations had higher concentrations of the 96-, 65-, and 42-kDa proteins. Qualitative differences between these two disruption methods were evident at the 102-, 96-, 91-, 50-, 38-, and 30-kDa protein bands. However, significant differences (P less than 0.05) were detected between the two methods at only the 102-, 96-, 91-, and 50-kDa bands.