A New Type of Air Bearing for Air-Driven High Speed Centrifuges

Pickels, Edward G.

doi:10.1063/1.1752366

Cited by 27 publications

(14 citation statements)

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“…The first step was accomplished by suspending the infected cords in buffer by means of a Waring blendor, by centrifuging the tissue suspension at 3800 l~.P.~, in a large angle centrifuge, by extracting the supernatant liquid with ether, and then by filtering the aqueous extracts through celite. The virus was sedimented, and aggregated colloidal material was removed by centrifugation in an air-driven centrifuge of the improved Pickels' design 1 (7). The virus used was the M. V. strain mixed with a strain provided by Dr. Charles Armstrong in 1936 and carried in monkeys since then by Dr. E. W. Schultz.…”

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confidence: 99%

Studies on the Purification of Poliomyelitis Virus

Loring

Schwerdt

1942

Journal of Experimental Medicine

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The application of high speed differential centrifugation to the purification of poliomyelitis virus has been a logical step since Stanley and Wyckoff (1) showed that relatively small and unstable plant viruses could be isolated as homogeneous materials by this method. The sedimentation of poliomyelitis virus in an ultracentrifuge was first demonstrated by Schultz and Raffel (2), and more recently Clark, Rasmussen, and White (3) obtained sediments which showed an irregular but in some instances high virus activity. While it has been shown that high speed centrifugation resulted in a sedimentation of the virus, evidence has not been provided that other macromolecular materials associated with normal tissue were not also sedimented along with the virus under these conditions. In view of the work of several investigators (4--6) on the concentration of macromolecular materials from various normal animal tissues, such constituents might very well be present together with virus in the high molecular weight fractions obtained from poliomyelitis-infected tissues.This paper presents the results of experiments on the application of differential centrifugation to the extracts of glycerolated or frozen, infected medullaecords from rhesus monkeys and to similar extracts of glycerolated or frozen, normal medullae-cords. The results show that when extracts of infected as well as normal cords, that have been stored in glycerol, are subjected to high speed centrifugation, appreciable yields of high molecular weight substances are obtained. However, when normal tissue that had been frozen and stored for appreciable lengths of time was used, no significant amount of high molecular weight, nitrogen-containing compounds was recovered. Frozen infected tissue, on the contrary, yielded small but significant amounts of high molecular weight material possessing both a high and uniform virus activity. EXPEB IM~.NTAL

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confidence: 99%

Studies on the Purification of Poliomyelitis Virus

Loring

Schwerdt

1942

Journal of Experimental Medicine

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“…Just before use, the frozen serum was thawed rapidly by immersion in a water bath at 40°C. Although most of the studies were carried out with unaltered serum, some experiments were performed with specimens concentrated in the following manner: After the second centrifugation at 13,000 l~.p.za, the clarified serum was centrifuged in the concentration vacuum centrifuge of Bauer and Pickels (7,10) for 3 hours at a speed of 27,300 lZ.P.~. Then the supernatant fluid was drawn off carefully with a sampling device described by Hughes, Pickels, and Horsfall (8) Ultracentrifuge.--The air-driven vacuum ultracentrifuge described by Bauer and Pickels (9) and by Pickels (10) was used in these studies.…”

Section: Methodsmentioning

confidence: 99%

Ultracentrifugation Studies of Yellow Fever Virus

Pickels

Bauer

1940

Journal of Experimental Medicine

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1. It was possible to study in the ultracentrifuge by optical methods the behavior of yellow fever virus particles directly in the unaltered serum from infected monkeys. 2. The virus showed an extremely high light absorption in the spectral range of 320 to 440 mµ, which seemed to be its intrinsic property. In a 1 cm. thickness of fluid, the small amount of virus present in unaltered infective serum absorbed about as much light (approximately 25 per cent) in the middle of this range as did all the normal serum proteins present in a combined concentration some 1000 times as great. 3. The concentration of virus in the unaltered serum was found to be of the order of 0.00005 gm. per cc. 1 cc. of a 10–9 dilution, which, as has been shown, may constitute a minimal infective dose for monkeys, would contain approximately 10,000 virus particles. The probability that most of the virus particles were in the inactive form is discussed. 4. In infective serum having a viscosity of 14 millipoises, the particles sediment with a blurred boundary at rates lying between approximately 18 and 30 x 10–13 cm./sec./dyne. Evidence indicates that this spread is the result of an aggregation or association phenomenon. 5. Computations of size are in approximate agreement with those made from ultrafiltration studies. On the assumption that the density of the virus particle is near that of protein, its volume is computed to be at least that of a spherical particle having a diameter of 12 mµ. An assumed density of 1.15 gm. per cc. yields a diameter of 19 mµ, considering the shape as spherical.

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“…centrifuge (17,18) at 30,600 l~.p.xt, for 3 hours. The gelE/tinous pellets of hemocyanin were resnspended to the original volume in 0.17 st saline buffered with phosphate at pH 6.9.…”

Section: Molecular Association 0i~ Hemocyaninmentioning

confidence: 99%

Molecular Association of Hemocyanin Produced by X-Rays as Observed in the Ultracentrifuge

Pickels

Anderson

1946

Journal of General Physiology

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1. When normal, monodisperse hemocyanin (60.5S) from Limulus Rolyphemus was irradiated in neutral buffer with x-rays, several new, more rapidly sedimenting ultracentrifugal components (86S, 107S, 122S) were produced, with a corresponding loss in the amount of the unaffected protein. The amount of the effect was roughly proportional to the amount of irradiation. 2. The new resolvable components apparently represented an association of the primary particles into aggregates of 2, 3, and 4 primary particles respectively. 3. The proportional amount of hemocyanin affected decreased almost to the vanishing point as the concentration of the protein was raised to high levels. 4. The absolute effect, i.e. the total number of particles affected in a given volume, increased with the concentration of hemocyanin, at least for concentrations below 15 per cent. 5. The presence of 33 per cent horse serum during irradiation inhibited the effect on the hemocyanin almost completely, with hemocyanin concentrations of both 0.8 and 14 per cent. 6. The presence of 2.8 per cent egg albumin during irradiation lowered the effect by about 70 per cent in the case of dilute preparations (0.8 per cent hemocyanin), but by only about 25 per cent in the case of 14 per cent solutions. 7. A lowering of the solution's oxygen tension during irradiation enhanced the effect, almost doubling it in some cases. 8. The probable theoretical significance of these and other observations are discussed in the text.

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A New Type of Air Bearing for Air-Driven High Speed Centrifuges

Cited by 27 publications

References 5 publications

Studies on the Purification of Poliomyelitis Virus

Studies on the Purification of Poliomyelitis Virus

Ultracentrifugation Studies of Yellow Fever Virus

Molecular Association of Hemocyanin Produced by X-Rays as Observed in the Ultracentrifuge

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