Experiments with growth of the eel trypanosome, Trypanosoma granulosum Laveran & Mesnil, 1902, in semi-defined and defined media

Abstract. Growth of the eel trypanosome, Trypanosoma granulosum , was attempted in five semi-defined and three defined media. Growth was poor in four semi-defined and two defined media, but one semi-defined medium, a modified version of SDM-79 without MEM F-14, supported good growth of the trypanosome. In this medium, doubling time was between 1 and 2 days, over 90% of organisms seen in culture after 6 days were trypomastigotes, and 1.8 × 0.1 × 10⁷ trypanosomes ml⁻¹ was achieved in 7 days. When foetal calf serum from the modified SDM-79 was substituted with insulin to create a fully defined medium, a modest but significant increase in cell numbers occurred compared with controls. In vitro experiments with D, L-alpha-difluoromethylomithine (DFMO) showed morphological changes leading to destruction of the trypanosome with increasing concentrations of the drug. A 50-mM concentration of DFMO inhibited growth by more than 90%, and the IC₅₀ was found to be 16 × 2 mM.