Kázmér Jobst

Electrokinetic analysis of the fetal erythrocyte membrane after trypsin digestion.

Summary: Treatment of intact erythrocytes with trypsin (TRY) produced a significant difference (P < 0.001) in electrophoretic mobility (EM) of fetal and adult cells. The greater net negative charge of the fetal red blood cells (RBC) at the “new electrokinetic surface” generated by TRY was further analyzed with cell-electrophoretic measurements combined with various enzymatic and chemical reactions.Formaldehyde or diazonium reaction known to eliminate positive (NH2) groups increased the net negativity of the TRY-digested adult and fetal RBC in the same extent leaving the distance between the EM values unchanged. When the TRY digestion was followed by neuraminidase (NASE) treatment, the decrease in EM of both types of erythrocytes was of the same magnitude, and the distance between the EM values of the TRY-treated fetal and adult RBC remained unchanged, too. Phospholipase-C (PLC) digestion performed after TRY treatment did not cause any change in EM, either in adult or in fetal RBC.The results show that the greater net negativity of the fetal RBC surface after TRY digestion can be attributed to neither less positive (NH2) groups, nor more sialic acid or phosphoric acid molecules existing at the new electrokinetic surface. It is suggested that the fetal RBC membrane may possess more acidic amino acid exposed to the outside, when TRY liberates sialoglycoprotein from the outer surface of the membrane.Speculation: Glycophorin seems to be the only major membrane protein in RBC which is readily accessible for TRY at the exterior cell surface. The new electrokinetic surface generated by TRY is characterized by the portion of glycophorin just behind the TRY splitting site. The results presented here might be explained by a supposed modification in the biogenesis of the glycophorin in fetal life. Amino acid analysis of the glycophorin fragments obtained with TRY digestion would serve a more intimate insight to the problem and would give information about the maturation from fetal to adult surface properties.

Cytoplasmic protein network in HeLa cells.

SummaryMonolayer HeLa culture nuclei isolated in situ with nonionic detergents remained attached to the glass as a “nuclear monolayer”. Searching for nuclear fixing structures a fine continous protein network was revealed around the isolated nuclei with fluorescence microscope after acridine orange staining.

Bisalbuminaemia in a Central European Family

A slow bisalbuminaemia, the first case reported in Central Europe, was diagnosed in a mother and both her children. The alloalbumin was homogeneous on SDS-acrylamide electrophoresis.

Bioluminescent monitoring of ATP release from human red blood cells treated with nonionic detergent.

The adaptation of the firefly luciferin-luciferase system for the detection of ATP in the presence of Triton X 100 or Brij 58 nonionic detergents is described. The method is sensitive, easy to perform and is suitable for the continuous monitoring of the mobilization rate of ATP from Triton X 100- or Brij 58-treated human erythrocytes. A very rapid ATP release was observed after Triton X 100 treatment of the red blood cells while the presence of Brij 58 caused a retarded mobilization of the intracellular ATP. The technique described seems to be applicable to all kinds of cells.