A Simple Monophasic Medium for Axenic Culture of Hemoflagellates

Abstract

An inexpensive, easily prepared monophasic medium which supports continuous culture of Leishmania donovani (.apprx. 4 .times. 107 cells/ml per day 5) and L. tarentolae (.apprx. 3.5 .times. 107 cells/ml per day 5) promastigotes was 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 (.apprx. 2 .times. 107 cells/ml per 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 .times. 105 cells which means that there was .apprx. 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 10-12 h; this shortened to 9.25 h at mid-log growth (day 2). The optimal pH range for L. donovani was 7.2-7.4 and optimal culture temperatures were 25.degree.-26.degree. C. A change was seen in the average size distribution of L. donovani promastigotes during the growth cycle with smaller cells predominating each succeeding day of culture. HO-MEM is a good medium for transformation of L. donovani amastigotes to promastigotes (60-80% in 48 h).