Bacteriophage SPP1

Abstract The lytic Bacillus subtilis bacteriophage SPP1 was isolated in Pavia (Subtilis Phage Pavia) and first described by Riva et al. (99). Interest in this phage derived at first from the observation that the complementary DNA strands of the phage were separable into a heavy strand (r 1.725 g/cm3) and a light strand (r 1.713 g/cm3) following denaturation and isopycnic centrifugation (99, 109). This observation and the finding that the phage was highly active in transfection led to the use of SPP1 in studies of mismatch repair (109). In later experiments the molecular biology of the phage, including its structure, total DNA sequence, genetics, and life cycle were established.