Published Papers

Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types: Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III. January 1944.

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Title:	Studies on the Chemical Nature of the Substance [1 of 23]
Alternative Title:	Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III
Creator:	Avery, Oswald T.
Contributor:	MacLeod, Colin M.
Publisher:	Journal of Experimental Medicine
Date:	1944-01-00
Subject:	Cellular signal transduction
Description:	From the Journal of Experimental Medicine Vol. 79, No. 1.
Type:	Text
Format:	text/plain
Language:	en
Identifier:	avery-pg01.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:	STUDIES ON THE CHEMICAL NATURE OF THE SUBSTANCE INDUCING TRANSFORMATION OF PNEUMOCOCCAL TYPES INDUCTION OF TRANSFORMATION BY A DESOXYRIBONUCLEIC ACID FRACTION ISOLATED FROM P-ELTyococcus TYPE III BY OSNVALD T. AVERY, M.D., COLIN 1A. MACLEOD, M.D., A"- MACLYN McCARTY,* M.D. (From the Hospital of The Rockefeller Institute for 1L2edical Research) PLATE 1 (Received for publication, November 1, 1943) Biologists have long attempted by chemical means to induce in higher organisms predictable and specific changes which thereafter could be trans- mitted in series as hereditary- characters. Among microorganisms the most striking example of inheritable and specific alterations in cell structure and function that can be experimentally induced and are reproducible under well defined and adequately controlled conditions is the transformation of specific types of Pneumococcus. This phenomenon was first described by Griffith (1) who succeeded in transforming an attenuated and non-encapsulated (R) variant derived from one specific type into fully encapsulated and virulent (S) cells of a heterologous specific type.š typical instance will suffice to illustrate the techniques originally used and serve to indicate the wide variety of trans- formations that are possible within the limits of this bacterial species. Griffith found that mice injected subcutaneously with a small amount of a living R culture derived from Pneumococcus Type II together with a large inoculum of heat-killed Type III (S) cells frequently succumbed to infection, and that the heart's blood of these animals yielded Type III pneumococci in pure culture. The fact that the R strain was avirulent and incapable by itself of causing fatal bacteremia and the additional fact that the heated suspension of Type III cells contained no viable or- ganisms brought convincing evidence that the R forms growing under these condi- tions had newly acquired the capsular structure and biological specificity of Type III pneumococci. The original observations of Griffith were later confirmed by Neufeld and Levia- thal (2), and by Baurhenn (3) abroad, and by Dawson (4) in this laboratory. Subse- quently Dawson and Sia (5) succeeded in inducing transformation in vitro. This they accomplished by growing R cells in a fluid medium containing anti-R serum and heat-killed encapsulated S cells.­hey showed that in the test tube as in the animal body transformation can be selectively induced, depending on the type specificity of the S cells used in the reaction system. Later, Alloway (6) was able to cause * `York done in part as Fellow in the Medical Sciences of the National Research Council.