Dye uptake by grampositive and gram-negative cells as related to adsorption laws.

Borzani and Vairo (1959) reported that grampositive and gram-negative microorganisms are fundamentally different with respect to crystal violet adsorption. They claimed that the binding of crystal violet by gram-positive cells followed the Freundlich and the Langmuir adsorption laws; whereas the binding of crystal violet by gram-negative cells did not follow any known adsorption law. The present paper presents evidence which does not support their conclusion regarding gram-negative cells. It has been found that the binding of crystal violet by both grampositive and gram-negative microorganisms can be interpreted as obeying adsorption laws.