Antineuralgica, Antipyretica, Antirheumatica

Schlesinger, Hermann

doi:10.1007/978-3-7091-9849-0_5

Cited by 3 publications

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“…While earlier studies (1-10) have indicated that bacteriophage might be obtained free of protein, or at least in a form which failed to give protein color tests, recent more exact studies (11)(12)(13)(14) concerning the chemical nature of bacteriophage have indicated that this active agent represents a new type of substance, the so called "heavy protein" with a molecular weight of many millions, similar to those isolated from tissues of animals (infected with equine encephalomyelitis (32) and with virus-induced rabbit papilloma (33)), and plants (infected with tobacco mosaic virus (32) and with cucumber viruses 3 and 4 (34), with potato virus "X" (35), and with tomato bushy stunt virus (36)). …”

Section: Discussionmentioning

confidence: 99%

“…Schleslnger (12)(13)(14) collected bacteriophage on a collodion membrane, purified it by repeated high speed centrifugation, and obtained a preparation which he described as having a density of 1.3 and consisting of spherical particles about 85 m# in diameter. Calculated on the basis of the lytic activity of the original material, the dry residue represented 4.3 X 10 -Is mg. of substance per unit of activity.…”

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confidence: 99%

“…In view of the evidence for the protein nature and relatively large molecular size of bacteriophage supplied by the experiments of Schlesinger (12)(13)(14), and particularly of Northrop (11), it was of interest to repeat the earlier (1927) experiments of Bronfenbrenner.…”

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Studies on the Purification of Bacteriophage

Kalmanson

Bronfenbrenner

1939

Journal of General Physiology

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A simple method of concentrating and purifying bacteriophage has been described. The procedure consisted essentially in collecting the active agent on a reinforced collodion membrane of a porosity that would just retain all the active agent and permit extraneous material to pass through. Advantage was taken of the fact that B. coli will proliferate and regenerate bacteriophage in a completely diffusible synthetic medium with ammonia as the only source of nitrogen, which permitted the purification of the bacteriophage by copious washing. The material thus obtained was concentrated by suction and after thorough washing possessed all the activity of the original filtrate. It was labile, losing its activity in a few days on standing, and was quickly and completely inactivated upon drying. This material contained approximately 15 per cent of nitrogen and with 2 or 3 mg. samples of inactive dry residue it was possible to obtain positive protein color tests. The concentrated and purified bacteriophage has about 10–14 mg. of nitrogen, or 6 x 10–17 gm. of protein per unit of lytic activity. Assuming that each unit of activity represents a molecule, the calculated maximum average molecular weight would be approximately 36,000,000, and on the assumption of a spherical shape of particles and a density of 1.3, the calculated radius would be about 22 millimicra. By measurement of the diffusion rate, the average radius of particle of the fraction of the purified bacteriophage which diffuses most readily through a porous plate was found to be of the order of magnitude of 9 millimicra, or of a calculated molecular weight of 2,250,000. Furthermore, when this purified bacteriophage was fractionated by forcing it through a thin collodion membrane, which permits the passage of only the smaller particles, it was possible to demonstrate in the ultrafiltrate active particles of about 2 millimicra in radius, and of a calculated molecular weight of 25,000. It was of interest to apply this method of purification to a staphylococcus bacteriophage. Since this organism does not readily grow in synthetic medium, a diffusate of yeast extract medium was employed. The better of two preparations contained about 10–12 mg. of nitrogen per unit of lytic activity. Although this is about one hundred times the amount of nitrogen found in an active unit of B. coli bacteriophage, nevertheless, the diffusion rate experiments gave results which paralleled those obtained with the coliphage. The diffusible particles of the crude staphylococcus bacteriophage had a radius of about 7 millimicra, and a calculated molecular weight of about 1,000,000, while the particles of the same phage which appeared in the ultrafiltrate through a thin collodion membrane had a radius of about 2.4 millimicra and a calculated molecular weight of about 45,000. It appears, therefore, that the active principle is distributed as particles of widely different sizes. However, since the smaller particles have all the properties of bacteriophage, the larger particles probably do not represent free molecules, but either are aggregates, or more likely, inactive colloids to which the active agent is adsorbed. The protein isolated, which bears the phage activity, is capable of stimulating the production of antilytic antibodies on parenteral injection into rabbits or guinea pigs. It retains its specific antigenicity when inactivated by formalin, but not when inactivated by drying.

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Section: Discussionmentioning

confidence: 99%

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Studies on the Purification of Bacteriophage

Kalmanson

Bronfenbrenner

1939

Journal of General Physiology

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“…Schlesinger also studied the adsorption mechanism of the virus to its host cell and found that the kinetics of adsorption imply that Brownian movement brings virus particles into random collisions with the bacterial surface (42). Most importantly, Schlesinger managed to purify a "weighable" amount of phage by differential centrifugation and graded filtration of crude phage suspensions, and found by direct chemical analysis of the pure virus that it consists mainly of protein and DNA, in roughly equal proportions (43,44). Although their small size renders bacterial viruses invisible in ordinary microscopes, Schlesinger was able to estimate directly the total number of phage particles in a purified virus preparation, by counting the number of bright points produced in a dark-field microscope.…”

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