title: Iron-modulated pseudocyst formation in Tritrichomonas foetus.
abstract: Iron is an essential element for the survival of trichomonads during host-parasite interaction. The availability of this metal modulates several metabolic pathways of the parasites and regulates the expression of virulence factors such as adhesins and proteolytic enzymes. In this study, we investigated the effect of iron depletion on the morphology and life cycle of Tritrichomonas foetus. Scanning and transmission electron microscopy analyses revealed that depletion of iron from the culture medium (named TYM-DIP inducer medium) induces morphological transformation of typical pear-shaped trophozoites into spherical and non-motile pseudocysts. Remarkably, inoculation of pseudocysts into an iron-rich medium (standard TYM medium), or addition of FeSO4 to a TYM-DIP inducer medium reverted the morphological transformation process and typical trophozoites were recovered. These results show that pseudocysts are viable forms of the parasite and highlight the role of iron as a modulator of the parasite phenotype. Although iron is required for the survival of T. foetus, iron depletion does not cause a cellular collapse of pseudocysts, but instead induces phenotypic alterations, probably in order to allow the parasite to survive conditions of nutritional stress. Together, these findings support previous studies that suggest pseudocysts are a resistance form in the life cycle of T. foetus and enable new approaches to understanding the multifactorial role of iron in the cell biology of this protozoan parasite.
authors.affiliation: Departamento de Medicina,Universidade Federal de São João Del Rei,Minas Gerais,Brazil.
authors.forename: Cássia
authors.initials: C
authors.lastname: Castro
authors.affiliation: Laboratório de Biologia Celular - Instituto Oswaldo Cruz,FIOCRUZ,Rio de Janeiro,Brazil.
authors.forename: Rubem Figueiredo Sadok
authors.initials: RF
authors.lastname: Menna-Barreto
authors.affiliation: Departamento de Medicina,Universidade Federal de São João Del Rei,Minas Gerais,Brazil.
authors.forename: Nilma DE Souza
authors.initials: Nde S
authors.lastname: Fernandes
authors.affiliation: Laboratório de Pesquisa em Leishmaniose - Instituto Oswaldo Cruz,FIOCRUZ,Rio de Janeiro,Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Saboia-Vahia
authors.affiliation: Laboratório de Biologia Molecular e Doenças Endêmicas-Instituto Oswaldo Cruz, FIOCRUZ,Rio de Janeiro,Brazil.
authors.forename: Geovane
authors.initials: G
authors.lastname: Dias-Lopes
authors.affiliation: Laboratório de Biologia Molecular e Doenças Endêmicas-Instituto Oswaldo Cruz, FIOCRUZ,Rio de Janeiro,Brazil.
authors.forename: Constança
authors.initials: C
authors.lastname: Britto
authors.affiliation: Laboratório de Pesquisa em Leishmaniose - Instituto Oswaldo Cruz,FIOCRUZ,Rio de Janeiro,Brazil.
authors.forename: Patricia
authors.initials: P
authors.lastname: Cuervo
authors.affiliation: Departamento de Medicina,Universidade Federal de São João Del Rei,Minas Gerais,Brazil.
authors.forename: José Batista
authors.initials: JB
authors.lastname: DE Jesus
mesh_terms: D000818:Animals; D003470:Culture Media; D006801:Humans; D007501:Iron / Q000494:pharmacology; D000090463:Iron Deficiencies; D008018:Life Cycle Stages / Q000187:drug effects*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010641:Phenotype; D011528:Protozoan Infections / Q000469:parasitology*; D016835:Tritrichomonas foetus / Q000254:growth & development* / Q000648:ultrastructure; D053058:Trophozoites / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D003470:Culture Media; D007501:Iron
keywords: Tritrichomonas foetus; iron; morphological transformation; pseudocyst; trophozoites