The induction of motility in Bacillus anthracis by means of bacteriophage lysates: significance for the relationship of Bacillus anthracis to Bacillus cereus.

Manninger and NogrMdi (1948) first reported the induction of encapsulation and motility in a nonmotile, unencapsulated, avirulent strain of BaciUus anthracis. Following Griffith's (1928) method they plated B. anthracis together with cell-free filtrates of a motile, encapsulated culture of BaciUus mesentericu var. vulgatus. After incubation either in CO2 or in air, typical colonies of B. anthracis were found, but, in addition, there appeared a number of slimy colonies corresponding neither to B. anthracis nor to B. mesenteri. The cells of these atypical colonies were characterized by a loose capsule and the presence of flagella. The authors concluded that such organis were variants of B. anthracis in which encapsulation and motility had been induced by a substance found in the capsular material of the "mesentericus" organism. Tomcsik (1949), although unable to confirm all of the resultsreportedby Manningerand Nogr4di, was successful in producing encapsulated mutants from unencapsulated strains of B. anthracis. He showed that the mutant isolated by Manninger and NogrAdi (1948) possessed capsular antigens common to both B. anthracis and B. mesentericus as well as other antigens not found in either of these species, and drew comparisons between this system and that involved in pneumococcus capsule type transformation reactions (McCarty, 1946). Later Tomcsik (1950) reported the observation of motility in some of the cultures of encapsulated mutants and showed that the motile mutants were related, both serologically and morphologically, more closely to B. anthracis than to any of the saprophytes tested. However, the motile mutants had lost their pathogenicity for test animals.