title: Biochemical and phylogenetic analyses of phosphatidylinositol production in Angomonas deanei, an endosymbiont-harboring trypanosomatid.
abstract: BACKGROUND
  The endosymbiosis in trypanosomatids is characterized by co-evolution between one bacterium and its host protozoan in a mutualistic relationship, thus constituting an excellent model to study organelle origin in the eukaryotic cell. In this association, an intense metabolic exchange is observed between both partners: the host provides energetic molecules and a stable environment to a reduced wall symbiont, while the bacterium is able to interfere in host metabolism by enhancing phospholipid production and completing essential biosynthesis pathways, such as amino acids and hemin production. The bacterium envelope presents a reduced cell wall which is mainly composed of cardiolipin and phosphatidylcholine, being the latter only common in intracellular prokaryotes. Phosphatidylinositol (PI) is also present in the symbiont and host cell membranes. This phospholipid is usually related to cellular signaling and to anchor surface molecules, which represents important events for cellular interactions.
  
  
  METHODS
  In order to investigate the production of PI and its derivatives in symbiont bearing trypanosomatids, aposymbiotic and wild type strains of Angomonas deanei, as well as isolated symbionts, were incubated with [(3)H]myo-inositol and the incorporation of this tracer was analyzed into inositol-containing molecules, mainly phosphoinositides and lipoproteins. Gene searches and their phylogenies were also performed in order to investigate the PI synthesis in symbiontbearing trypanosomatids.
  
  
  RESULTS
  Our results showed that the bacterium did not incorporate the tracer and that both strains produced similar quantities of PI and its derivatives, indicating that the symbiont does not influence the production of these metabolites. Gene searches related to PI synthesis revealed that the trypanosomatid genome contains an inositol transporter, PI synthase and the myo-inositol synthase. Thus, the host is able to produce PI either from exogenous myo-inositol (inositol transporter) or from myo-inositol synthesized de novo. Phylogenetic analysis using other organisms as references indicated that, in trypanosomatids, the genes involved in PI synthesis have a monophyletic origin. In accordance with experimental data, sequences for myo-inositol transport or for myo-inositol and PI biosynthesis were not found in the symbiont.
  
  
  CONCLUSIONS
  Altogether, our results indicate that the bacterium depends on the host to obtain PI.
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. allan@biof.ufrj.br.|Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil. allan@biof.ufrj.br.|Laboratório Nacional de Computação Científica, Av. Getúlio Vargas, 333, Quitandinha, Petrópolis, RJ, CEP: 25651-075, Brazil. allan@biof.ufrj.br.
authors.forename: Allan C
authors.initials: AC
authors.lastname: de Azevedo-Martins
authors.affiliation: Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. alvesjmp@gmail.com.
authors.forename: João M P
authors.initials: JM
authors.lastname: Alves
authors.affiliation: Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco C, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. fgmello@biof.ufrj.br.
authors.forename: Fernando Garcia
authors.initials: FG
authors.lastname: de Mello
authors.affiliation: Laboratório Nacional de Computação Científica, Av. Getúlio Vargas, 333, Quitandinha, Petrópolis, RJ, CEP: 25651-075, Brazil. atrv@lncc.br.
authors.forename: Ana Tereza R
authors.initials: AT
authors.lastname: Vasconcelos
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. wsouza@biof.ufrj.br.|Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil. wsouza@biof.ufrj.br.|Instituto Nacional de Metrologia, Qualidade e Tecnologia - Inmetro, Rio de Janeiro, RJ, Brasil. wsouza@biof.ufrj.br.
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.affiliation: Laboratório de Biomembranas, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. einicker@biof.ufrj.br.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Einicker-Lamas
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Avenida Carlos Chagas Filho, 343, Bloco G, Subsolo, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, CEP 21941-590, Brazil. motta@biof.ufrj.br.|Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Rio de Janeiro, Brazil. motta@biof.ufrj.br.
authors.forename: Maria Cristina M
authors.initials: MC
authors.lastname: Motta
mesh_terms: D001419:Bacteria / Q000302:isolation & purification; D005786:Gene Expression Regulation / Q000502:physiology; D010716:Phosphatidylinositols / Q000378:metabolism*; D010802:Phylogeny; D013559:Symbiosis; D014351:Trypanosomatina / Q000235:genetics / Q000378:metabolism*
chemical_list: D010716:Phosphatidylinositols