A simple monophasic medium for axenic culture of hemoflagellates.

An inexpensive, easily prepared monophasic medium which supports continuous culture of Leishmania donovanì (approximately 4 X 10(7) cells/ml/day 5) and L. tarentolae (approximately 3.5 X 10(7) cells/ml/day 5) promastigotes has been developed. This medium, designated HO-MEM, is a modified Eagle's minimal essential medium with Spinner's salts and 10% fetal calf serum. Epimastigotes of Trypanosoma cruzi, Costa Rica strain, also grew well in HO-MEM (approximately 2 X 10(7) cells/ml/day 5) but cells of the Corpus Christi strain grew poorly in the medium. The initial inoculum for all of the above culture systems was 3 X 10(5) cells which means that there was approximately 100-fold increase in cell number within 5 days of culture. Average doubling time for L. donovani in HO-MEM during log growth phase was 10 to 12 hr; this shortened to 9.25 hr at mid-log growth (day 2). The optimal pH range for L. donovani was 7.2 to 7.4 and optimal culture temperatures were 25 to 26 C. A change was seen in the average size distribution of L. donovani promastigotes during the growth cycle with smaller cells predominating each succeding day of culture. HO-MEM is a good medium for transformation of L. donovani amastigotes to promastigotes (60 to 80% in 48 hr).