The Identification of a Steroid Synthesized by the Protozoan, Tetrahymena Pyriformis.

摘要

The primary objective, the identification of a steroid synthesized by the Protozoan, Tetrahymena pyriformis, has been completed. This high melting alcohol (m.g. 312.5-314.5) which is the principal component of the nonsaponifiable lipid fraction from this organism has been assigned a molecular structure based on studies employing a number of techniques including mass spectrometry, nuclear magnetic resonance spectroscopy, optical rotary dispersion measurements, and x-ray crystallography. The correctness of the structure proposed has been confined by independent synthesis of tetrahymanel and some of its derivatives. A second objective, the demonstration of sterol alteration by these cells, has been initiated. The transformation of cholesterol to 22-dehydro-cholesterol and to 7,22-bisedehydrocholesterol has been established. Studies with 14C-labelled cholesterol verify the two dehydrogenated compounds are derived from cholesterol. The biological activity of sterols in this organism has led to a study of RNA catabolism. The nucleotidase activity was found to include a nonspecific particulate acid phosphatase and a specific soluble 3'-nucleotidase with a neutral pH optinum. No alkaline phosphatase or specific 5'-nucleotidase with a neutral or alkaline pH optinum was detected. (Author)