title: Dynamics of polymorphism of acidocalcisomes in Leishmania parasites.
abstract: Growth of Leishmania mexicana amazonensis promastigotes in different culture media resulted in structurally and chemically different acidocalcisomes. When grown in SDM-79 medium, the promastigotes showed large spherical acidocalcisomes of up to 1.2 microm diameter distributed throughout the cell. X-ray microanalysis and elemental mapping of the organelles showed large amounts of oxygen, phosphorus, sodium, potassium, magnesium, calcium, and zinc. Immunofluorescence microscopy using antisera raised against a peptide sequence of the vacuolar-type proton pyrophosphatase of Arabidopsis thaliana that is conserved in the Leishmania enzyme, indicated localization in acidocalcisomes. When cells were transferred to Warren's medium, the acidocalcisomes transformed from spherical into branched tubular organelles. The labeling pattern of the vacuolar proton-pyrophosphatase, considered as a marker for the organelle, changed accompanying the structural changes of the acidocalcisomes, and the enzyme showed an apparently lower proton-transporting activity when measured in digitonin-permeabilized promastigotes. X-ray microanalysis and elemental mapping of these structures revealed the additional presence of iron. Together, the results reveal that the morphology and composition of acidocalcisomes are greatly influenced by the culture conditions.
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Brigadeiro Trompovski, s/n., bloco G, Cidade Universitaria, CEP 21949-900, Rio de Janeiro, Brazil.
authors.forename: Kildare
authors.initials: K
authors.lastname: Miranda
authors.forename: Roberto
authors.initials: R
authors.lastname: Docampo
authors.forename: Orlando
authors.initials: O
authors.lastname: Grillo
authors.forename: Anderson
authors.initials: A
authors.lastname: Franzen
authors.forename: Márcia
authors.initials: M
authors.lastname: Attias
authors.forename: Anibal
authors.initials: A
authors.lastname: Vercesi
authors.forename: Helmut
authors.initials: H
authors.lastname: Plattner
authors.forename: Joachim
authors.initials: J
authors.lastname: Hentschel
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
mesh_terms: D000165:Acridine Orange / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000032:analysis; D003470:Culture Media / Q000494:pharmacology; D022162:Cytoplasmic Vesicles / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure*; D004577:Electron Probe Microanalysis; D021621:Imaging, Three-Dimensional; D043564:Inorganic Pyrophosphatase / Q000032:analysis / Q000187:drug effects; D007501:Iron / Q000032:analysis / Q000378:metabolism; D007894:Leishmania mexicana / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D008561:Membrane Fusion / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D009550:Nigericin / Q000494:pharmacology
chemical_list: D003470:Culture Media; D007501:Iron; D043564:Inorganic Pyrophosphatase; D000165:Acridine Orange; D009550:Nigericin; D002118:Calcium