B-u-1 – Trypanosoma Cruzi Incorporates Phospholipids from Rhodnius Prolixus’ Midgut

In insects the importance of lipid metabolism has been widely recognized. Neutral lipids and fatty acids constitute the major lipids of insect hemolymph whereas phospholipids are the main lipid class found in the midgut. In insect hemolymph lipophorins are the molecules responsible for lipid transfer between the tissues involved in lipid absorption, storage and utilization. We have previously demonstrated that Rhodnius prolixus’ midgut are able to take up 14C-oleic acid from lipophorin preferentially at 10th after a blood meal. The fatty acids are used to synthesizes neutral lipids (40%) and phospholipids (60%). The neutral lipids are released to hemolymph but phospholipids remained in the organ and are used to synthesizes midgut’s membranes. When Rhodnius prolixus are infected with Trypanosoma cruzi these parasites multiplies and develops in intestine of insect attached to the membranes. Now we are studying the capacity of T. cruzi to incorporate phospholipids from R. prolixus’ midguts membranes. The infection of Trypanosoma cruzi increases 2-fold the 3H-palmitic acid incorporation by midgut from hemolymphatic lipophorin. The time course was linear up to 30 minutes. The 3Hpalmitic acid was used to synthesizes mainly phospholipids membranes (70% from total lipids). In order to separate the parasites from membranes after 3H-palmitic acid incorporation the luminal content was subject to a Percoll gradient. In the infected midguts the 3H-phospholipids were found associated with T. cruzi. These data indicate that R. prolixus’ midgut can provide essential lipids which will perhaps constitute parasite membranes.