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Biomedical subjects

A Polson

Publications and source records attributed to A Polson.

At least 91 records · Page 5Linked to original sources
PubMed1968

'Tanned' gelatin spheres and granules for exclusion chromatography.

1. The preparation of tanned gelatin spheres and granules from high-molecular-weight gelatin is described. This material is comparatively hard, giving high flow rates, is insoluble in water at temperatures between 0 degrees and 100 degrees and is resistant to digestion by trypsin and chymotrypsin. The high-molecular-weight fraction of gelatin was prepared by precipitation with polyethylene glycol, and the spheres and granules prepared from this fraction were hardened and insolubilized by tanning with either formalin or chromium salts or both. 2. The spheres and granules were used successfully for the separation of protein molecules and other protein-aceous materials ranging in molecular weight from 200 to greater than 6000000. This gel exclusion material has several properties superior to those of other products used for similar purposes. Further, it was noticed that the porosity of the spheres differed considerably from that of the granules.

Chemical Phenomena↗
PubMed1967

Variation of sedimentation coefficient with rotor velocity.

The sedimentation coefficients of three proteins, which appeared homogeneous in the ultracentrifuge, have been determined at different rotor velocities. Two of the proteins, ovalbumin and human gamma-globulin, showed sedimentation coefficients that were approx. 10% higher at rotor velocities below 20000rev./min. than at 56100rev./min. The third protein, haemocyanin of Jasus lalandii, could not be investigated over the same rotor-velocity range, but it showed a similar effect.

Animals↗
PubMedDate not supplied

Binding and elution of serum glycoproteins from agarose.

Evidence in support of previous observations by different authors that agarose is not an entirely inert support in affinity chromatography is presented. In the present communication it is shown that 8% granulated agarose adsorb serum glycoproteins in 10mM phosphate buffer, pH 7.2 and desorb these in 200mM NaCl in 10mM phosphate buffer, pH 7.2. The desorbed glycoproteins retained their abilities to react with antibodies elicited in sheep to normal human serum glycoproteins, despite the loss of mannose and galactose following the agarose treatment.

Adsorption↗
PubMedDate not supplied

Purification of viruses by electrophoresis in sucrose concentration gradients. 1972.

Zone electrophoresis (ZE) in concentration gradients of sucrose proved to be a powerful technique in the purification of viruses although it is seldomly used as a single step for the separation of the infective agent from extraneous matter but usually as a final procedure. No difficulties were experienced in the purification of plant viruses with ZE possibly because of the resistance of the agents to the chloroform butanol treatment which the impure plant viruses received prior to the ZE. Likewise no difficulties were encountered during purification of human and animal picorna viruses because they also are resistant to chloroform or chloroform-butanol treatment prior to ZE. Purification of animal and possibly human reoviridae ZE as a final step is involved as they are associated with or even attached to the host cell membranes which are lipoidal in nature. Because the lipoidal material on the virus has an affinity for organic solvents the virus particles are caught in the emulsion when an extract of the crude virus material is shaken with the organic solvent. With these viruses polyethylene glycol M(r) 6000 (PEG) is often helpful as a means of displacing most of the host proteins as a step in the partial purification prior to ZE. Neurotropic African horse sickness virus which presented many problems to overcome was rendered free of extraneous proteins to the extent that electron micrographs could be made of it. Neurotropic Rift Valley fever virus was similarly difficult to purify as it was always associated with mouse brain components. This virus was finally purified from infected mouse blood in which the virus particles were not associated with host cell debris and other extraneous proteins. Zone electrophoresis experiments were not conducted on viruses with large particle sizes e.g. myxoviruses because they could be purified without a great deal of effort using polymer displacement, and thin layer centrifugation. Zone electrophoresis as a means of final purification was vividly displayed with the purification of five viruses of the larvae of the pine emperor moth, Nudaurelia cytheria cytheria.

Cell Fractionation↗