title: Mitochondrial behaviour throughout the lytic cycle of Toxoplasma gondii.
abstract: Mitochondria distribution in cells controls cellular physiology in health and disease. Here we describe the mitochondrial morphology and positioning found in the different stages of the lytic cycle of the eukaryotic single-cell parasite Toxoplasma gondii. The lytic cycle, driven by the tachyzoite life stage, is responsible for acute toxoplasmosis. It is known that whilst inside a host cell the tachyzoite maintains its single mitochondrion at its periphery. We found that upon parasite transition from the host cell to the extracellular matrix, mitochondrion morphology radically changes, resulting in a reduction in peripheral proximity. This change is reversible upon return to the host, indicating that an active mechanism maintains the peripheral positioning found in the intracellular stages. Comparison between the two states by electron microscopy identified regions of coupling between the mitochondrion outer membrane and the parasite pellicle, whose features suggest the presence of membrane contact sites, and whose abundance changes during the transition between intra- and extra-cellular states. These novel observations pave the way for future research to identify molecular mechanisms involved in mitochondrial distribution in Toxoplasma and the consequences of these mitochondrion changes on parasite physiology.
authors.affiliation: Wellcome Centre for Molecular Parasitology, University of Glasgow, UK.
authors.forename: Jana
authors.initials: J
authors.lastname: Ovciarikova
authors.affiliation: Wellcome Centre for Molecular Parasitology, University of Glasgow, UK.
authors.forename: Leandro
authors.initials: L
authors.lastname: Lemgruber
authors.affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors.forename: Krista L
authors.initials: KL
authors.lastname: Stilger
authors.affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.|Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Sullivan
authors.affiliation: Wellcome Centre for Molecular Parasitology, University of Glasgow, UK.
authors.forename: Lilach
authors.initials: L
authors.lastname: Sheiner
mesh_terms: D002460:Cell Line; D006801:Humans; D008018:Life Cycle Stages; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000378:metabolism / Q000648:ultrastructure; D001678:Organelle Biogenesis; D014122:Toxoplasma / Q000254:growth & development / Q000472:pathogenicity* / Q000648:ultrastructure