STUDIES IN THE VARIABILITY OF TUBERCLE BACILLI: V. ACID AGGLUTINATION AND ELECTROPHORETIC POTENTIAL IN MYCOB. LEPRAE

Abstract

Previous work has indicated that various species of acid-fast bacteria including the tubercle bacilli may be separated into S and R types on the basis of colony structure and virulence; some results suggest that the two types differ in respect to the surface potential charge on the individual organisms. In this paper it is shown that S and R types of Mycob. leprae suspended in distilled water show a difference in electrophoretic potential of approximately five times the probable error of the determinations. Suspensions of S organisms are shown to have an isoelectric point of pH 1.2 compared with a pH of 2.2 in the case of a suspension of R organisms. Although acid agglutination of the S and R suspensions was found to occur at widely different pH levels, the agglutination occurred at approximately the same electrophoretic potential for both types, namely, at about 18.2 millivolts.