THE ELECTROPHORETIC MIGRATION OF VARIOUS TYPES OF VEGETABLE CELLS

Abstract

To determine how much the phenomena of cataphoretic charge are dependent on forces inherent in the water itself and how much they are affected by the specific physical and chemical properties of the suspended cell, the authors observed the electrophoretic migration of 12 vegetable microorganisms, representing widely separated biological types, in 3 menstrua[long dash]distilled water, Ringer''s solution and a solution of 0.145 M NaCl (isotonic with Ringer''s solution)[long dash]making observations in each of the 3 menstrua at reactions between pH 1.5 and pH. 12.5. Besides silica dust, they studied a green alga, a yeast, and representative bacteria. They agreed with other workers that vegetable organisms normally bear a considerable negative charge which causes them to migrate toward the anode. Slight additions of acid (pH 6.5) or alkali (pH 8.5) or neutral salts cause an increase in velocity. Further addition of electrolytes causes a decrease in the charge which is dependent on the concentrations of cations. This effect of the cations is proportional to their valency but the H-ion exhibits a special power due to its high migration velocity. With H and with trivalent cations the cell''s charge is frequently reversed and becomes positive. In a mixture of cations other than H-ion the resultant effect is usually cumulative. In a mixture of H-ion and other univalent cations the influence of the former is largely neutralized by the weaker ions. Besides these general effects, which were always observed, distinct and significant differences were found between electrophoretic migration curves plotted for various types of suspended particles. Silica dust is much less reduced in charge than the vegetable cells by either H or other cations. Chlorella was the least affected of the organisms studied, while Bact. coli, Ps. pyocyanea and L. acidophilus were the most affected. The organisms showed marked differences in the different menstrua with the same electrolytes. All organisms were affected most by the electrolytes when suspended in water. The chemical and physical constitution of the cell plays at least some part in determining the effect of electrolytes upon electrophoretic charge.