Abstract
1. From Type III pneumococci a biologically active fraction has been isolated in highly purified form which in exceedingly minute amounts is capable under appropriate cultural conditions of inducing the transformation of unencapsulated R variants of Pneumococcus Type II into fully encapsulated cells of the same specific type as that of the heat-killed microorganisms from which the inducing material was recovered. 2. Methods for the isolation and purification of the active transforming material are described. 3. The data obtained by chemical, enzymatic, and serological analyses together with the results of preliminary studies by electrophoresis, ultracentrifugation, and ultraviolet spectroscopy indicate that, within the limits of the methods, the active fraction contains no demonstrable protein, unbound lipid, or serologically reactive polysaccharide and consists principally, if not solely, of a highly polymerized, viscous form of desoxyribonucleic acid. 4. Evidence is presented that the chemically induced alterations in cellular structure and function are predictable, type-specific, and transmissible in series. The various hypotheses that have been advanced concerning the nature of these changes are reviewed.
Full Text
The Full Text of this article is available as a PDF (1.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Dawson M. H., Sia R. H. IN VITRO TRANSFORMATION OF PNEUMOCOCCAL TYPES : I. A TECHNIQUE FOR INDUCING TRANSFORMATION OF PNEUMOCOCCAL TYPES IN VITRO. J Exp Med. 1931 Oct 31;54(5):681–699. doi: 10.1084/jem.54.5.681. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dawson M. H. THE INTERCONVERTIBILITY OF "R" AND "S" FORMS OF PNEUMOCOCCUS. J Exp Med. 1928 Mar 31;47(4):577–591. doi: 10.1084/jem.47.4.577. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dawson M. H. THE TRANSFORMATION OF PNEUMOCOCCAL TYPES : II. THE INTERCONVERTIBILITY OF TYPE-SPECIFIC S PNEUMOCOCCI. J Exp Med. 1930 Jan 1;51(1):123–147. doi: 10.1084/jem.51.1.123. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dubos R., Avery O. T. DECOMPOSITION OF THE CAPSULAR POLYSACCHARIDE OF PNEUMOCOCCUS TYPE III BY A BACTERIAL ENZYME. J Exp Med. 1931 Jun 30;54(1):51–71. doi: 10.1084/jem.54.1.51. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dubos R., Bauer J. H. THE USE OF GRADED COLLODION MEMBRANES FOR THE CONCENTRATION OF A BACTERIAL ENZYME CAPABLE OF DECOMPOSING THE CAPSULAR POLYSACCHARIDE OF TYPE III PNEUMOCOCCUS. J Exp Med. 1935 Jul 31;62(2):271–279. doi: 10.1084/jem.62.2.271. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Macleod C. M., Mirick G. S. Quantitative Determination of the Bacteriostatic Effect of the Sulfonamide Drugs on Pneumococci. J Bacteriol. 1942 Sep;44(3):277–287. doi: 10.1128/jb.44.3.277-287.1942. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martland M., Robison R. The preparation and use of the bone phosphatase. Biochem J. 1929;23(2):237–242. doi: 10.1042/bj0230237. [DOI] [PMC free article] [PubMed] [Google Scholar]