Adaptation of Leishmania cells to in vitro culture results in a more efficient reduction and transport of biopterin

Leishmania major and Leishmania donovani cells freshly isolated from infect ed animals divided slowly as axenic promastigotes but the addition of biopt erin in the culture medium greatly enhanced their growth. However, when cel ls were subjected to serial passages and adapted to culture, this growth-pr omoting effect of biopterin was no longer observed. Genetic analysis of the se culture-adapted Leishmania cells demonstrated that the genes coding for the pterin reductase PTR1 or for the biopterin transporter BT1 were overexp ressed. This suggests that Leishmania cells adapted to culture were more ef ficient in utilizing biopterin, an essential growth factor in Leishmania. ( C) 2001 Academic Press.