This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Frampton, E. W. Articles by Mandel, M. Search for Related Content PubMed PubMed Citation Articles by Frampton, E. W. Articles by Mandel, M.

 Previous Article  |  Next Article 

J Virol. 1970 January; 5(1): 8-13
Copyright © 1970 American Society for Microbiology. All Rights Reserved.

Properties of the Deoxyribonucleic Acid Contained in the Defective Particle Coliphage 15 ¹

Department of Biology, The University of Texas, M. D. Anderson Hospital and Tumor Institute at Houston, Houston, Texas 77025

ABSTRACT

Escherichia coli strain 15 TAU, which requires thymine, arginine, and uracil for growth and harbors an apparently defective prophage, was induced by exposure to ultraviolet light (580 ergs/mm²) or to mitomycin C (5 µg/ml). Phage particles (coliphage 15) were recovered from the resulting lysate by treatment with deoxyribonuclease, filtration, and several cycles of differential centrifugation. Analysis of the phage particles obtained by using cesium chloride density gradient centrifugation in a preparative ultracentrifuge resulted in the resolution of three components. The major component had a peak density of 1.52 to 1.53 g/cm³ followed by components with densities of 1.5 and 1.49 g/cm³. The guanine plus cytosine content of coliphage 15 deoxyribonucleic acid (DNA) was determined by both analytical ultracentrifugation in cesium chloride and by thermal denaturation in standard saline citrate buffer. Respective values of 46.4 ± 1% and 46.6 ± 1% guanine plus cytosine content were obtained. Coliphage 15 DNA formed molecular hybrids with messenger ribonucleic acid (RNA) from both uninduced and ultraviolet-induced cultures of E. coli 15 TAU, but did not hybridize with E. coli ribosomal RNA. The molecular weight of coliphage 15 DNA was determined by constant velocity sucrose density gradient centrifugation to be about 33 x 10⁶ daltons.

² Present address: Department of Biological Sciences, Northern Illinois University, DeKalb, Ill. 60115.

¹ Presented in part at the 68th Annual Meeting of the American Society for Microbiology, Detroit, Mich., 5-10 May 1968.