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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 [8 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-pg08.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:	F P EUMO O AL TYPES out at morn temperature Lmless specifically stated otherwise.›ecause of the tho-. retical advantage of working at low temperature in the preparation of biologically active material, the purification of one lot (preparation 44 was carried out in the cold. In tb is instance all the above procedures with the exception of desoxycholate ex- extractioTand enzyme treatment were conducted in a cold room maintained at 0-4'C. This preparation proved to have significantly higher activity than did material simi- larl prepared at room temperature. Desox ehlate extraction of tke heat-killed cells at low temperature is less efficient and yield% smaller amounts of the active fraction. It has been dernontrated that higher temperatures facilitate extraction of the active principle, although activity is best preserved at lour temperatures. Analysis f P f fed Tra sf or…2dMaterial General Pro erls'es.¢ i nee solutions containing 0.5 to 1.0 mg. per cc. o f [he purified substance are colorless and clear in diffuse Eight.¡owever, 'in strong trau rMtted light the e se l u tio.n is not en direly clear and when stirred exhibits a silky sheen.¬olutions .t these concentrations are highly viscous. Purified material dissolved in physiological salt solution and stored a t 2-4* C. retain its activity i a u rid irn irri shed t ite r f o r a t le as t¦ouths.¡owever,¡ e n dissolved in distilled water, i t rapidly decreases in activity and becomes com- pletely inert within a few days.¬aline solution stored in the frozen state in a C 02 ice box…2d 70T.) retain full potency for several months.¢milarl , material precipitated from saline solution b alcohol and stored under the supernatant remains active over a tong period f time. Partially purified material ran be preserved b dryirr from the frozen state in the l ophile apl cratus. However, when the same procedure is used for the preservation of the highly purified substance, i t is found that. the material iinderge e s changes resulting in decrease i n so I ub i city and loss Gf activity. The activity o f the transforming principle in crude extracts withstands h a, t i ri far 0 to 60 minutes a t 65'C. Highly purified preparation o f active, nia t r is l are less stable, and s tne loss o f activity occurs -at this temperature. quantitative stud¨f the effect of heading purified material a t higher tem- peratures has not a s yet been made.‘lowa…286), using crude extracts pre pa red fro m Ty p¢ II pnc umcrco ccal cell s, found tha t o ccasiona 11š etivitœou 11 still be demonstrated after 10 minutes' exposure in the water bath to tem- peratures as high as­a The procedures mentioned above were carried out with solutions adjusted to neutral reaction, sonce it has been shorn that hydrogen ion concentrations i n the acid range result i n progressive loss o f activity. Inactivation occurs rapidly at pH and below, Qal­ive Chemical Tests.-The puriMed material in concentrated solution gives negative biuret and Millon teas.­hese tests have been dome directly on dry rna terial with negative results.­he D ische d iph en lam fine reaction