An Improved Chemically Defined Medium for Mass Cultures of Tetrahymena: Nutrient Uptake and Growth Regulation

SUMMARY: A chemically defined medium for growing mass cultures of Tetrahymena was developed. The growth characteristics and the effects of variations in the culture conditions and medium constituents were studied. The results show that Tetrahymena can be grown in a completely defined medium with rates and yields nearly comparable to those obtained in non-defined media. In the defined medium, K+ but not Na+, was indispensable for growth; unlike in media containing proteose peptone, the growth rate was independent of the presence of insoluble Fe3+ complexes, but was more dependent on culture temperature. Although Tetrahymena has an absolute requirement for preformed purine and pyrimidine bases in addition to several amino acids, its proliferation and growth were primarily under amino acid control.