The Magnesium Requirement of Tetrahymena

Abstract

Since Mg is an important coenzyme in the glycolytic cycle, and since the Mg requirement of Tetrahymena geleii (strain E) has not been ascertained, it was decided to evaluate the effect of Mg on growth in respect to the amt. of glucose substrate. In media containing no glucose at pH 6.5, max. growth was obtained upon the addition of 1 [mu]g./ml. of mg. One-third growth inhibition was obtained at pH 7.5 with 0.1% Mg. When glucose was raised to 250 [mu]g./ml., as little as 0.1 [mu]g./ml. of Mg produced a definite growth response. Max. growth for this level of glucose was obtained upon the addition of 1 [mu]g./ml. of Mg. Full growth was obtained with 10 [mu]g./ml. of Mg in media containing 0.1% glucose. Both max. growth and the growth rate were effected by the amt. of Mg present up to 10 [mu]g./ml. Much slower growth rates were obtained in Mg-deficient media.