title: The Symbiotic Bacterium Fuels the Energy Metabolism of the Host Trypanosomatid Strigomonas culicis.
abstract: The mutualistic relationship between trypanosomatids and their respective endosymbiotic bacteria represents an excellent model for studying metabolic co-evolution since the symbiont completes essential biosynthetic routes of the host cell. In this work, we investigated the influence of the endosymbiont on the energy metabolism of Strigomonas culicis by comparing the wild strain with aposymbiotic protists. The bacterium maintains a frequent and close association with glycosomes, which are distributed around the prokaryote. Furthermore, 3D reconstructions revealed that the shape and distribution of glycosomes are different in symbiont-bearing protists compared to symbiont-free cells. Results of bioenergetic assays showed that the presence of the symbiont enhances the O2consumption of the host cell. When the quantity of intracellular or released glycerol was evaluated, the aposymbiotic strain presented higher values when compared to symbiont-containing cells. Furthermore, inhibition of oxidative phosphorylation by potassium cyanide increased the rate of glycerol release and slightly diminished the ATP content in cells without the symbiont, indicating that the host trypanosomatid enhances its fermentative activity when the bacterium is lost.
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Loyola-Machado
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Allan Cézar
authors.initials: AC
authors.lastname: Azevedo-Martins
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Carolina Moura Costa
authors.initials: CMC
authors.lastname: Catta-Preta
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.affiliation: Laboratório de Bioenergética e Fisiologia Mitocondrial, Instituto de Bioquímica Médica Leopoldo De Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Antonio
authors.initials: A
authors.lastname: Galina
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil. Electronic address: motta@biof.ufrj.br.
authors.forename: Maria Cristina M
authors.initials: MCM
authors.lastname: Motta
mesh_terms: D018407:Bacterial Physiological Phenomena; D004734:Energy Metabolism; D013559:Symbiosis; D014351:Trypanosomatina / Q000382:microbiology*
keywords: Cell evolution; cell ultrastructure; endosymbiosis; glycosome; respiration; trypanosomatid.