Effect of Temperature on Growth and Nutritional Requirements of Leishmania tarentolae in a Defined Medium*

SYNOPSIS. Leishmania tareiatolar grown in Trager's defined medium grew best at 21° and 28°C. There was a long lag phase at 33° with low population peaks. At 33° the long lag phase after each transfer showed that L. tarentolae had not completely adapted to the higher temperature. Red blood cell extract stimulated growth at 28° and permitted good growth at 33°, indicating that the defined medium was not optimal. Subculture of leptomonads at 37° failed even with addition of red blood cell extract and various tissue‐culture media. Survival for 1 week was obtained when small amounts of reinforced Eagle's Medium, “conditioned” by human female hermaphrodite fibroblauts, was added. Peniallin had no effect but streptomycin inhibited growth, concentrations as low as 33 μg/ml producing partial inhibition.