Characterization of Bacteriophage gh-1 for Pseudomonas putida

Abstract

Lee, Lucy F. (Michigan State University, East Lansing), and J. A. Boezi . Characterization of bacteriophage gh-1 for Pseudomonas putida . J. Bacteriol. 92: 1821–1827. 1966.—Bacteriophage gh-1 of Pseudomonas putida A.3.12 was isolated and purified by differential centrifugation and diethylaminoethyl (DEAE) cellulose chromatography. An electron micrograph of the phage stained with uranyl acetate revealed a regular hexagonal outline about 50 mμ across with a short wedge-shaped tail attached at one corner of the head. The phage formed 10% as many plaques on P. putida C1S as on P. putida A.3.12, the organism used in the isolation procedure. No plaques were formed on P. fluorescens (ATCC 9712) or P. aeruginosa . The latent period of the infectious cycle was 21 min, and the average burst size was 103. The nucleic acid component of gh-1 is double-stranded deoxyribonucleic acid (DNA), with a base composition of 57.0% guanine plus cytosine (G + C) as determined by chemical analysis. The per cent G + C of P. putida A.3.12 DNA measured in a similar manner was 63.7%. The buoyant density of phage gh-1 measured by cesium chloride equilibrium centrifugation was 1.45 g/cm 3 , whereas that of gh-1 DNA, heat-denatured gh-1 DNA, and P. putida A.3.12 DNA was 1.716, 1.730, and 1.722 g/cm 3 , respectively. The per cent G + C of gh-1 DNA and P. putida A.3.12 DNA calculated from the buoyant densities was 57.1 and 63.3%, respectively. The sedimentation coefficients, S 50 20,w , of gh-1 and the phenol-extracted gh-1 DNA, measured by the boundary sedimentation velocity method, were 460 and 18.9, respectively. The molecular weight of phenol-extracted gh-1 DNA, calculated by use of the equation of Burgi and Hershey, is 6 × 10 6 .