THE INFLUENCE OF THIAMINE AND ITS CATABOLITES ON THE MAGNITUDE OF ELECTROPHORETIC VELOCITY AND THE ζ-POTENTIAL OF YEAST SACCHAROMYCES CEREVISIAE

Problem: Yeast cell solutions are thought to be more stable with an increase in the negative charge of their cell surface, which can be controlled by the level of ζ-potential or electrophoretic velocity. Thiamine is known as a yeast growth stimulant, but the effect of vitamin B1 and its catabolites on the state of yeast membranes has not been investigated. Aim. The purpose of the work is to determine the effect of different concentrations of thiamine, thiaminedisulfide, 4-methyl‑5-β-oxyethylthiazole and thiochrome on the value of the ζ-potential and electrophoretic velocity in Saccharomyces cerevisiae. Methods. Determination of electrophoretic velocity and ζ-potential was carried out using a microelectrophoresis unit and a microscope, the movement of yeast cells along Hemocytometer was observed. It was determined in what time (sec) the cells will pass a path equal to the side of the square in the Hemocytometer. Parameters: voltage in the circuit – 100 V, the distance between the electrodes – 2 cm, the path traveled by the yeast cells – 0.02 cm (control test). In the test samples, thiamine and its catabolites were added to the yeast suspension 15 minutes before the measurements in final concentrations of 1, 5, 10 μmol. The main results: Incubation of yeast with thiamine, which was added to the medium at concentrations of 5 and 10 μmol, increased the ζ-potential and electrophoretic velocity, respectively, by 2.75 and 1.84 times compared with the control. Thiaminedisulfide at a concentration of 10 μmol increased the studied indicators by 2.61 times, and thiochrome at a concentration of 1 μmol – by 4.26 times compared with the control. The introduction of 4-methyl‑5-β-oxyethylthiazole into the mediumat a concentration of 1 and 5 μmol also caused an increase by 1.43 and 1.24 times, respectively, compared with the control. Conclusions. Thiamine and its metabolites increased electrophoretic velocity and ζ-potential of yeast cells. Thiaminedisulfide and thiamine increased the level of the studied indicators at concentrations, respectively 10 μmol, and 5 and 10 μmol due to enhancement of oxidation processes in yeast cells, while thiochrome and 4-methyl‑5β-oxyethylthiazole acted at concentrations, 1 μmol, 1 and 5 μmol, respectively, apparently, due to the interaction with the hydrophobic pockets of proteins.