Springer Online Journal Archives 1860-2000
Summary Host specific restriction was detected in 13 Bacillus strains, when 63 strains of Bacillus subtilis and 15 other Bacillus strains were tested with phage Φ105C. These 13 strains were classified into 8 groups (M,H,C,N,E,F,G,P) by the type of restriction. M-type strains (B. subtilis Marburg 168, its derivatives, and two other strains) showed relatively weak restriction, restricting Φ105C from other groups of Bacillus by ratios of 10-1 to 10-3. Strains of groups H,C,N,E,F,G, and P restricted Φ105C from other groups by ratios of 10-2 to 10-8. It was confirmed with some of the strains that type-specific modification was endowed only by the last host. Furthermore, we isolated one restriction deficient mutant of B. subtilis marburg 168-YS11, which had also lost its modification phenotype.
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