Giardia lamblia: Identification of peroxisomal-like proteins
Karla Acosta-Virgen1, Bibiana Chávez-Munguía1, Daniel Talamás-Lara1
1Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, Mexico.
Abstract:
The protozoan parasite Giardia lamblia has traditionally been reported as lacking peroxisomes, organelles involved in fatty acid metabolism and detoxification of reactive oxygen species. We here report the finding with transmission electron microscopy of an oxidase activity in cytoplasmic vesicles of trophozoites and cysts of G. lamblia. These vesicles were positive to 3,3'-diaminobenzidine and to cerium chloride staining. In addition, using bioinformatic tools, two peroxisomal proteins were identified in the G. lamblia proteome: acyl-CoA synthetase long chain family member 4 (ACSL-4) and peroxin-4 (PEX-4). With confocal and immunoelectron microscopy using polyclonal antibodies both proteins were identified in cytoplasmic vesicles of trophozoites. Altogether, our results suggest for the first time the presence of peroxisomal-like proteins in the cytoplasm of G. lamblia.
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