Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis of Polypeptides from Bacteraides melaninogenicus

1 Sodium dodecyl sulphate-polyacrylamide gel electrophoresis has been applied to proteins extracted from 32 strains of Bacteroides melaninogenicus. 2 Strains of subspecies melaninogenicus gave similar electrophoretic patterns which differed from those of strains outside the subspecies. 3 Strains of subspecies intermedius serotype C were similar to one another in electrophoretic pattern, and were different from strains outside the subspecies and from one strain of subspecies intermedius of serotype C1. 4 Greater variation was observed between asaccharolytic than between saccharolytic strains. 5 The group within subspecies asaccharolyticus with low G + C content stained poorly and showed few bands. 6 The group within subspecies asaccharolyticus with high G + C content showed interstrain differences but none would be confused with strains of the saccharolytic subspecies. The strain that did not react with type B antiserum was electrophoretically different from those strains that did. 7 The asaccharolytic Lev type strains form a separate group based on both electrophoretic and physiological criteria.