title: Ultrastructural and cytochemical identification of megasome in Leishmania (Leishmania) chagasi.
abstract: The present work showed the presence of a megasome in Leishmania (Leishmania) chagasi amastigotes. Transmission electron microscopy analysis of ultrathin serial sections and three-dimensional reconstruction allowed visualization of large structures in amastigote forms of L. (L.) chagasi and a multivesicular tubule-lysosome structure in metacyclic promastigotes. Morphometric data showed that the relative volume occupied by the megasome and the multivesicular tubule (MVT)-lysosome structures was about 5% and 3.2%, respectively, in amastigotes and promastigotes of L. (L.) chagasi. Further characterization of the megasome in L. (L.) chagasi amastigotes was carried out by immunolabeling of cysteine proteinase, whereas the lysosomal content of amastigotes and promastigotes was confirmed by arylsulfatase cytochemistry.
authors.affiliation: Centro de Microscopia Eletrônica, Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Botucatu, 862-Térreo, CEP 04023-062 São Paulo, Brazil.
authors.forename: Sanny O
authors.initials: SO
authors.lastname: Alberio
authors.forename: Suzana S
authors.initials: SS
authors.lastname: Dias
authors.forename: Flávio P
authors.initials: FP
authors.lastname: Faria
authors.forename: Renato A
authors.initials: RA
authors.lastname: Mortara
authors.forename: Clara L
authors.initials: CL
authors.lastname: Barbiéri
authors.forename: Edna
authors.initials: E
authors.lastname: Freymüller Haapalainen
mesh_terms: D000818:Animals; D005407:Flagella / Q000648:ultrastructure; D007891:Leishmania / Q000166:cytology* / Q000648:ultrastructure; D008247:Lysosomes / Q000648:ultrastructure; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000648:ultrastructure; D015388:Organelles / Q000648:ultrastructure