Anaerobic Metabolism in T4 Acanthamoeba Genotype.

Abstract

Members of the genus Acanthamoeba are of the most common protozoa that has been isolated from a variety of environment and affect immunocompromised individuals, causing granulomatous amoebic encephalitis and skin lesions. Acanthamoeba, in immunocompetent patients, may cause a keratitis related to corneal microtrauma. These free-living amoebas easily adapt to the host environment and wield metabolic pathways such as the energetic and respiratory ones in order to maintain viability for long periods. The energetic metabolism of cysts and trophozoites remains mostly unknown. There are a few reports on the energetic metabolism of these organisms as they are mitochondriate eukaryotes and some studies under aerobic conditions showing that Acanthamoeba hydrolyzes glucose into pyruvate via glycolysis. The aim of this study was to detect the energetic metabolic pathways with emphasis on anaerobic metabolism in trophozoites of three isolates of Acanthamoeba sp belonging to the T4 genotype. Two samples were collected in the environment and one was a clinical sample. The evaluation of these microorganisms proceeded as follows: rupture of trophozoites (7.5 × 103 parasites/ml) and biochemical analysis with high performance liquid chromatography and spectrophotometry. The anaerobic glycolysis was identified through the detection of glucose, pyruvate, and lactate. The protein catabolism was identified through the detection of fumarate, urea, and creatinine. The fatty acid oxidation was identified through the detection of acetate, beta-hydroxybutyrate, and propionate. The detected substances are the result of the consumption of energy reserves such as glycogen and lipids. The anaerobic glycolysis and protein catabolism pathways were observed in all three isolates: one clinical and two environmental. This study represents the first report of energetic pathways used by trophozoites from different isolates of the T4 genotype Acanthamoeba.