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Independent Functions of Viral Protein and Nucleic Acid in Growth of Bacteriophage. September 20, 1952.

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Title:	Independent Functions of Viral Protein and Nucleic Acid in Growth of Bacteriophage [3 of 18]
Creator:	Chase, Martha
Contributor:	Hershey, Alfred Day, 1908
Publisher:	Journal of General Physiology
Date:	1952-09-20
Subject:	Molecular biology Molecular genetics
Description:	From the Journal of General Physiology Vol. 36, No. 1.
Type:	Text
Format:	text/plain
Language:	en
Identifier:	hersheychase-pg03.jpg
Source:	Master scanned with Epson GT-10000+ flatbed scanner at 600 dpi.
Rights:	http://osulibrary.orst.edu/specialcollections/coll/pauling/dna/copyright.html
Full Text:	A. D. HERSHEY AND MARTHA CHASE 41 the phage. The radiochemical purity of the preparations is somewhat uncertain, ow- ing to the possible presence of inactive phage particles and empty phage membranes. The presence in our preparations of sulfur (about 20 per cent) that is precipitated by antiphage serum ('Table I) and either adsorbed by bacteria resistant to phage, or not adsorbed by bacteria sensitive to phage (Table VII), indicates contamination by membrane material. Contaminants of bacterial origin are probably negligible for present purposes as indicated by the data given in Table I. For proof that our prin- cipal findings reflect genuine properties of viable phage particles, we rely on some experiments with inactivated phage cited at the conclusion of this paper. Tlte Chemical Morphology of Resting Phage Particles.-Anderson (1949) found that bacteriophage T2 could be inactivated by suspending the particles in high concentrations of sodium chloride, and rapidly diluting the suspension with water. The inactivated phage was visible in electron micrographs as tad- pole-shaped "ghosts." Since no inactivation occurred if the dilution was slow TABLE I Composition of Ghosts and Solution of Plasmolyzed Phage Per cent of isotope] Whole phage labeled with Plasmolyzed phage labeled with Pat ! gU Acid-soluble ..................... ......... .. 1 Acid-soluble after treatment with DNase....... 1 1 80 1 Adsorbed to sensitive bacteria.. ............... 85 I 90 2 90 Precipitated by antiphage. . . ....... . . ........ 90 99 5 97 he attributed the inactivation to osmotic shock, and inferred that the particles possessed an osmotic membrane. Herriott (1951) found that osmotic shock released into solution the DNA (desoxypentose nucleic acid) of the phage particle, and that the ghosts could adsorb to bacteria and lyse them. He pointed out that this was a beginning toward the identification of viral functions with viral substances. We have plasmolyzed isotopically labeled T2 b5- suspending the phage (10`1 per ml.) in 3 m sodium chloride for 5 minutes at room temperature, and rapidly pouring into the suspension 40 volumes of distilled water. The plas- molyzed phage, containing not more than 2 per cent survivors, was then an- alyzed for phosphorus and sulfur in the several ways shown in Table I. The results confirm and extend previous findings as follows: 1. Plasmolysis separates phage T2 into ghosts containing nearly all the sulfur and a solution containing nearly all the DNA of the intact particles. 2. The ghosts contain the principal antigens of the phage particle detect- able by our antiserum. The DNA is released as the free acid, or possibly linked to sulfur-free, apparently non-antigenic substances.