Characterization of Lytic Bacteriophages of Bacilius thuringiensis

A group of six phages, GV-1 to GV-6, was characterized. These phages use a strain of Bacillus thuringiensis var. galleriae, serotype V, esterase type 5, as host. The phages were divided into three types: Group I, phages GV-1, GV-2 and GV-4; Group II, phages GV-3 and GV-5; Group III, phage GV-6. Their morphology, plaque morphology, host range, serum neutralization, adsorption rates, one-step growth characteristics, calcium requirements, thermal inactivation and stability were examined. Distinction between the groups was clear-cut, and sufficient differences were observed between individual phages within a group to allow differentiation. Group I phages do not resemble any of the phages previously reported as replicating in B. thuringiensis; group II phages resembled the B. subtilis phage GA-1 (Bradley, 1965); GV-6 phage may be similar to a previously reported B. thuringiensis phage (Chapman & Norris, 1966).