A procedure for the isolation of deoxyribonucleic acid from micro-organisms

For many years immunologists have been well served by the viewpoint that the immune system's primary goal is to discriminate between self and non-self. I believe that it is time to change viewpoints and, in this essay, I discuss the possibility that the immune system does not care about self and non-self, that its primary driving force is the need to detect and protect against danger, and that it does not do the job alone, but receives positive and negative communications from an extended network of other bodily tissues.

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Tolerance, danger, and the extended family.

Nobel Lecture: Prions

Peptidoglycan types of bacterial cell walls and their taxonomic implications.

Patients With Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic) A Collaborative Report from the American Association for Vascular Surgery/Society for Vascular Surgery,* Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease) Endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation

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ACC/AHA 2005 Practice Guidelines for the Management of Patients With Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic)

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.

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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

Oswald T. Avery, Colin M. MacLeod, Maclyn McCarty: Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types

Studies on the chemical nature of the substance inducing transformation of pneumococcal types

The data presented in this paper establish the finding that multiple specific protective antibodies exist in rabbits in response to immunization with Group B streptococci. The summary in Table I indicates the serological types into which Group B streptococci have been divided on the basis of their antigenic composition. This classification is dependent upon passive protection of mice with antibodies directed against the specific antigens, and types are defined in these terms. Heretofore, it was thought that type-specific polysaccharides accounted for all such protection in Group B streptococci. Certain exceptions of cross-protection between types due to minor polysaccharide determinants soon appeared; cross-protection reactions based on protein determinants in at least two types were also discovered. The present experiments show that specific antibodies directed to either polysaccharide or protein antigens of a single strain can be protective against infection with streptococci containing these antigens.

/pdf/multiple-mouse-protective-antibodies-directed-against-group-nd7of0kktt.pdf

Multiple mouse-protective antibodies directed against group B streptococci. Special reference to antibodies effective against protein antigens.

Determination of C-reactive protein in the blood as a measure of the activity of the disease process in acute rheumatic fever

Lysis of trypsinized Group A streptococcal cell walls with phage-associated lysin releases into solution dialyzable and non-dialyzable mucopeptide fractions composed of N-acetylglucosamine, N-acetylmuramic acid and alanine, glutamic acid, lysine, and glycine in addition to the characteristic group-specific carbohydrate. The latter substance contains appreciable amounts of N-acetylmuramic acid and the amino acids as well as N-acetylglucosamine and rhamnose. Hot formamide extraction of the cell walls results in a soluble fraction of group-specific carbohydrate and an insoluble residue. The Group A carbohydrate in this instance is composed of rhamnose and N-acetylglucosamine. The composition of the insoluble residue is similar to that of the mucopeptide fractions released from the cell wall by phage-associated lysin. This residue was shown by electron microscopy to be composed of discrete discs which appear similar in structure to the intact cell wall. The specific carbohydrate obtained by hot formamide extraction of Group A-variant cell walls was composed almost exclusively of rhamnose. The residue fraction was similar to that of Group A. The residue of cell walls extracted with hot formamide is extensively solubilized not only by phage-associated lysin and S. albus enzyme, but also by lysozyme, which has no measurable effect on the intact streptococcal cell wall.

https://rupress.org/jem/article-pdf/114/1/127/1080373/127.pdf

Studies on the chemical structure of the streptococcal cell wall. I. The identification of a mucopeptide in the cell walls of groups A and A-variant streptococci.

Maclyn McCarty

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

Studies on the chemical nature of the substance inducing transformation of pneumococcal types

Multiple mouse-protective antibodies directed against group B streptococci. Special reference to antibodies effective against protein antigens.

Determination of C-reactive protein in the blood as a measure of the activity of the disease process in acute rheumatic fever

Studies on the chemical structure of the streptococcal cell wall. I. The identification of a mucopeptide in the cell walls of groups A and A-variant streptococci.