TEMPERATURE AND METABOLISM IN LEISHMANIA .I. RESPIRATION IN L DONOVANI, L MEXICANA, AND L TARENTOLAE

Leptomonads of Leishmania donovani, L. mexicana, and L. tarentolae were grown in blood-agar-Locke's-overlay medium, harvested by centrifugation, and their respiration measured by conventional Warburg techniques from 30 to 39 °C in (1) Locke's Solution without glucose, (2) Locke's with glucose, and (3) Locke's with one-half volume hemolyzed, citrated whole rabbit blood. Both the endogenous and substrate-stimulated respiratory rates of all species rose with temperature but dropped above 35 °C in L. mexicana and L. tarentolae and above 37°C in L. donovani. In addition, the respiratory rate of L. mexicana and L. donovani in dilute blood dropped during the first 2 hours of measurement but could be significantly increased by the addition of fresh blood up to 33 °C in L. mexicana and up to 39 °C in L. donovani. It was concluded that the metabolism of the cutaneous L. mexicana was adversely affected at a lower temperature than that of the visceral L. donovani. The respiratory temperature coefficients of the mammalian L. mexicana and L. donovani also differed significantly from those of L. tarentolae (of reptilian origin), indicating perhaps a temperature-stabile system for utilization of exogenous substrate in the latter species. © 1969.