Trypanosoma cruzi: growth requirements at different temperature in fetal bovine serum or peptide supplemented media.
An enriched synthetic medium with low molecular weight peptides allows Trypanosoma cruzi epimastigotes to grow at 26-37 C. Using this medium, the growth requirements of T. cruzi were compared at different temperatures. When supplemented with fetal bovine serum or serum peptides, nine amino acids were absolutely required from the first passage, while additional amino acids and amino acid precursors were needed to support growth during a second passage. Five amino acids (beta-alanine, glutamine, cysteine, ornithine, and threonine) were also required absolutely at temperatures ranging between 30 and 37 C. Nine vitamins were needed at all temperatures, while ascorbic acid and ergocalciferol were not necessary at any temperature. The remaining amino acids and vitamins showed a variable role as growth factors depending on the temperature increase. In peptide supplemented media, requirements for amino acids and their precursors, as well as vitamins and nucleotides, increased markedly when compared with the protein supplemented medium. A peptide composed of one glutamic acid, two alanines, and one lysine can substitute for serum for trypanosomal growth at all temperatures. Several minimum media have been prepared in which epimastigote forms of T. cruzi can grow at 26-37 C for more than 10 passages.