Cell Models Representing Various Types of Living Cells

Abstract

The behavior of a variety of cells can be roughly imitated by models 1 consisting of a non-aqueous substance (representing the plasma membrane) placed between dye solution and artificial sap (representing vacuolar sap). The rates of penetration of dye into the sap are compared during one hour. The range of pH values studied is between pH 5 and pH 9.

(1) When chloroform 1 is used as the membrane. (a) Penetration of dye from cresyl blue solution at pH 9 into the sap at pH 5 has a high temperature coefficient (Q₁₀ = 2.3 between 15° and 25°C.) This may depend on the change in the viscosity of chloroform. A similar explanation may account for the high temperature coefficient in the penetration of the dye into the sap of Nitella and Valonia. (b) From cresyl blue solution at pH 9 the dye accumulates rapidly in the sap at pH 5 as in Nitella.

(2) When aniline is used as the membrane, (a) The higher the pH value of the cresyl blue solution and lower the pH value of the sap, the more rapid is the rate of penetration and accumulation of dye in the sap. From the solution at pH 9, the dye passes into aniline chiefly as the dye base and upon reaching the sap it is converted to the dye salt. From the solution at pH 5 the dye passes into aniline chiefly as dye salt, (b) The lower the pH value of a phenol red solution and higher the pH value of the sap, the greater is the rate of penetration and accumulation of dye in the sap. The dye accumulates rapidly in the sap at a high pH from phenol red solution at low pH; the dye passes into aniline as free acid (yellow) and is converted by the sap to the dye salt (red).