Sterol requirements of a ciliate Tetrahymena corlissi Th-X : I. A nutritional analysis of the sterol requirements of T. Corlissi Th-X

Abstract

1. 1. Tetrahymena corlissi Th-X, a tetrahymenid ciliate, has been cultivated under axenic conditions in a medium of known chemical composition (within limits of contemporary standards of chemical purity) and required a sterol for best growth. 2. 2. It responded to many plant and animal 3ß-OH sterols and their esters, with saturated and unsaturated ring systems and variously-substituted side chains. 3. 3. The activity of potential cholesterol precursors was correlated approximately with their presumed proximity to cholesterol; however, tritiated lophenol was not converted to cholesterol or sterols of comparable polarity but was directly incorporated. 4. 4. dl-α-Glycerophosphate, oleic acid and other oleate-containing compounds, and some synthetic phosphatides, spared the sterol requirement and permitted submaximal growth in the absence of sterol.