Induction and Properties of a Temperate Bacteriophage from Bacillus stearothermophilus

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Abstract
Welker , N. E. (University of Illinois, Urbana), and L. Leon Campbell . Induction and properties of a temperate bacteriophage from Bacillus stearothermophilus . J. Bacteriol. 89: 175–184. 1965.— Bacillus stearothermophilus 1503-4R growing at 55 C was induced to lyse either when 0.05 μg/ml of mitomycin C was added or when it was exposed to ultraviolet light for 30 sec. Lysis of the induced cultures occurred 45 to 60 min after induction. Phage were assayed on B. stearothermophilus 4S giving turbid plaques 0.05 to 0.3 cm in diameter. Noninduced cultures of 1503-4R spontaneously produced one phage per 2.8 × 10 6 bacterial cells. The optimal temperature for phage production and assay was found to be 55 C. B. stearothermophilus 1503-4R was immune to the isolated temperate phage (TP-1) and to a clear-plaque mutant phage (TP-1C), even when tested at phage mutliplicities of 100. TP-1 and TP-1C phage were identical morphologically having a head 65 mμ in diameter and a tail 240 mμ long and 12 mμ wide. TP-1C phage deoxyribonucleic acid (DNA) had an S 20,w value of 24.1 and a calculated molecular weight of 1.21 × 10 7 . DNA base compositions of TP-1 and TP-1C phage were identical (42% guanine + cytosine), but differed significantly from those of the lysogenic or indicator strains of B. stearothermophilus (50% guanine + cytosine). No unusual bases were detected in either the bacterial or phage DNA.