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Biomedical subjects

R Drzeniek

Publications and source records attributed to R Drzeniek.

At least 19 recordsLinked to original sources
PubMed1980

Preparative isoelectric focusing of poliovirus polypeptides in urea-sucrose gradients.

Isoelectric focusing in urea using small density gradient columns for dissociated poliovirus resulted in a complete separation of the four virus polypeptides. Identification and purity of VP1, 2, 3 and 4 was shown by SDS-polyacrylamide gel electrophoresis. The isoelectric points were determined and compared with the values obtained in gels. The recovery of the individual polypeptides was about 80%. Up to 500 microgram of poliovirus per tube could thus be separated in a one-step procedure giving pure and SDS-free poliovirus polypeptides.

Electrophoresis, Polyacrylamide Gel↗
PubMed1978

Isoelectric focusing of viral polypeptides in urea. A methodological study on poliovirus.

The applicability of isoelectric focusing in urea to the analysis of viral polypeptides is reported, using poliovirus as a model. Experimental techniques for the dissociation of virus particles, for isoelectric focusing in urea-containing polyacrylamide gels (rods, flat bed and slab gels) and for pH measurement and two-dimensional analysis are described and their results, as applied to poliovirus polypeptides, discussed. Special attention is given to problems of recovery of all of the proteins and the incidence of artifacts. The influence of reagents, dissociation conditions, focusing procedures and preparation and storage of virus material on the occurrence of charge modifications of the polypeptides has been investigated. Some recommendations are made for the application of the method to other viruses of particles.

Isoelectric Focusing↗
PubMed1978

Isoelectric points of polypeptides of standard poliovirus particles of different serological types and of empty capsids and dense particles of poliovirus type 1.

The isoelectric points of polypeptides of standard and dense poliovirus particles and of empty capsids have been determined by isoelectric focusing in urea and by two-dimensional analysis. Comparing virus strains belonging to the three serological types of poliovirus, differences in the pI of some, but not all of the structural polypeptides are found. The pI of polypeptides of dense particles and of empty capsids are identical with those of standard particles. Polypeptide VPo present in empty capsids has a pI between those of VP4 and VP2.

Capsid↗
PubMed1978

The effect of cesium salts on dense poliovirus particles.

The buoyant density of dense poliovirus particles has been examined in density gradients other than cesium chloride in order to determine the dependence of this property on the nature of the solvent. In Urografin (sodium and methylglucamine amidotrizoate), dense poliovirus particles banded at two densities--1.33 and 1.39 g/cm(3)--whereas in cesium metrizoate they banded only at 1.39 g/cm(3) and in cesium sulfate at 1.38 g/cm(3). The presence of cesium ions gives rise to the occurrence of dense particles, which are indistinguishable in their buoyant density and sedimentation coefficient from standard poliovirus particles when prepared in the absence of Cs+. In their physical properties dense poliovirus particles are more closely related to rhinoviruses and foot-and-mouth-disease virus, i.e., to members of the genus Rhinovirus, than to standard poliovirus particles belonging to the genus Enterovirus.

Capsid↗
PubMed1977

Differences in the physical properties of dense and standard poliovirus particles.

Dense poliovirus particles (DP) differ in buoyant density, sedimentation coefficient and lability from standard poliovirus particles. Dense particles band at a density of 1-44 g/ml in isopycnic CsCl gradients and sediment in sucrose gradients at 220S. However, when DP are centrifuged in sucrose gradients containing 1-5 M-KCl, NaCl or LiCl, two types of particles are observed, one sedimenting at 220S and the other at 160S. Particles sedimenting at 220S are converted into particles sedimenting at 160S by incubation at 37 degrees C in 1-5 M-KCl. The high buoyant density seems to be correlated with the high lability of DP. Dense particles are extremely labile in isotonic phosphate-buffered saline. Their degradation proceeds through an RNA-containing particle lacking polypeptide VP4, to RNA and empty capsids.

Capsid↗
PubMed1977

Structural subunits of poliovirus particles by electron microscopy.

Electron microscopy of poliovirus particles and empty capsids under various conditions of specimen deposition and staining visualizes the dissociation products of these particles. The dissociation proceeds in steps; it begins with the expansion of particles and leads to the final product of the dissociation--a cluster of several sub-particles of equal size (approx. 100 A in diam.). A scheme of the dissociation is proposed on the basis of the observed intermediates.

Capsid↗
PubMed1976

Demonstration of a core in poliovirus particles by electron microscopy.

Electron microscopic examination of poliovirus in CsCl-solutions without conventional staining with phosphotungstic acid or uranyl acetate revealed the existence of cores inside poliovirus particles. Empty capsids could not be visualized by this technique. Evidently, CsCl can enhance the contrast of the virus particle to an extent sufficient for the study of poliovirus particles by electron microscopy under conditions in which they exhibit specific properties.

Capsid↗
PubMed1975

Isolation and characterization of 'dense particles' from poliovirus-infected HeLa cells.

Dense poliovirus particles (buoyant density 1.44 g/ml in CsCl) isolated from infected HeLa cells contain the normal four structural polypeptides VP1 to VP4, and 35S poliovirus RNA. In addition, small amounts of VPo and single-stranded RNA sedimenting slower than the poliovirus genome are present. Dense particles have a low specific infectivity, are neutralized by type-specific poliovirus antisera, and are detected during growth as early as normal virus but disappear when virus production stops. They appear to represent a different, more open, conformation of the normal virus capsid.

Amino Acids↗