In chloroplasts of Spinacea oleracea L., Hg2+ ions interact with some sites in the photosynthetic electron transport chain: (l) with the intermediates Z+/D+ situated in the D1 and D2 proteins and with the manganese cluster in the oxygen evolving complex which are located on the donor side of photosystem (PS) 2, (2) with the chlorophyll a dimer in the core of PS1 (P700). P700 is oxidized in the dark by HgCl2. The Hg2+ ions form organometallic complexes with amino acids contained in chloroplast proteins. and F. Šeršeň, K. Král'ová, A. Bumbálová.
The haemolytic action of different concentrations of HgCl2 on rat red blood cells (RBC ) was studied in vitro. The concentrations of HgCb in incubating media were 0.15, 0.25 and 0.50 mmol.l'1. The ionic strength of the media varied from 0 to 154 mmol.l1 NaCl, Isotonicity of solutions was also compensated using isotonic glucose in different concentrations (287-0 mmol.l"1). Osmolarity of solutions varied from 287 to 308 mOsm. Besides these solutions the haemolysis in Krebs-Ringer solution was also studied. Haemolysis was characterized with two maxima in all concentrations of Hg2+. The first maximum was observed at low ionic strength and the second one at high ionic strength. In relation to the increased concentrations of Hg2+, the first maximum of haemolysis progressively declined towards the higher ionic strength. In the Krebs-Ringer solutions, the increased concentration of Hg2+ was followed by reduced haemolysis. The haemolytic concentration of 0.15 mmol.l"1 was found to be optimal.
The haemolytic action of HgCl2 (0, 15 mmol.l'1) was studied in relation to the ionic strength and concentration of glucose and saccharose in incubating medium. Blood from 94 donors, aged 19-46 years were used in our experiments. In relation to the ionic strength the haemolytic action was characteristic with two maxima of haemolysis. The first at low ionic strength and second one at the high. Both maxima in solutions containing saccharose were significantly diminished in glucose. These facts show a negative influence of saccharose on the haemorheological properties of the erythrocyte membrane.