Energetic metabolism of axenic promastigotes of Leishmania (Viannia) braziliensis.

Leishmania spp are protozoans capable of carbohydrates degradation and as energy source they can use glucose, aminoacids or lipids from the environment. The products of the metabolic pathways such as organic acids may be used as an index of their energetic metabolic profile. Therefore, in this study a metabolic profile comparison was made between promastigotes from one reference strain (MHOM/BR/1975/M2903) and two different isolates of Leishmania (Viannia) braziliensis (MHOM/BR/2003/IMG3 and MHOM/BR/2005/RPL5). The parasites culture was performed in complete Grace's culture media seeded in 24-well plates at 26°C. During the growth curve performance samples were collected from the logarithmic and stationary phases of culture and therefore analyzed by high performance liquid chromatography (HPLC) and spectrophotometry assays to determine the concentrations of glucose, lactate, citrate, α-ketoglutarate, succinate, fumarate, malate, oxaloacetate and β-hydroxybutirate which are indicative of the energetic pathways. It was possible to detect an increase in the glucose from the stationary phase from the M2903 strain when compared to the logarithmic phase while in the IMG3 and RPL5 isolates there was a decrease (p<0.05). The spectrophotometric and chromatographic results indicated that the logarithmic phase which presents higher energy consumption due to the intense replication rate have the energetic pathways intensified. It was also possible to note some metabolic differences between the analyzed parasites which may indicate possible adaptations of the parasite when facing different environmental and physiological conditions during its life cycle and that these differences may help in the understanding of the diversity of the host-parasite relationship from Leishmania parasites.