title: Entamoeba histolyticaelectrondense granules secretion in vitro and in vivo: ultrastructural study.
abstract: Electron dense granules (EDGs) were identified by transmission electron microscopy in Entamoeba histolytica trophozoites recovered from hamster liver lesions. Abundant granules were present in trophozoites recovered after 15 min of liver inoculation. Variation in the size and morphology of these EDGs was also observed. Numerous granules were present in the plasma membrane when these parasites were incubated for 5 min with MDCK monolayers. Release of these EDGs was suggested by the presence of granules in contact with the surface of the target cell plasma membrane. Parasite phagocytic invaginations were observed after 10 min of parasite-monolayer interaction. In these structures, scarce granules were seen. Granules secretion was corroborated by obtaining of a pellet of these small structures from the incubation of trophozoites with collagen supernatant. Collagenase and gellatinase activity of this pellet was identified in SDS-PAGE gels. EDGs were also present in amebic hamster liver lesions. Our observations corroborate that these granules are secreted and suggest that may participate in the cytopathic effect of E. histolytica both in vitro and in vivo.
authors.affiliation: Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Av. IPN 2508, Zacatenco, 07360 Mexico City, Mexico. bchavez@cinvestav.mx
authors.forename: Bibiana
authors.initials: B
authors.lastname: Chávez-Munguía
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Castañón
authors.forename: Verónica
authors.initials: V
authors.lastname: Hernández-Ramírez
authors.forename: Mónica
authors.initials: M
authors.lastname: González-Lázaro
authors.forename: Patricia
authors.initials: P
authors.lastname: Talamás-Rohana
authors.forename: Adolfo
authors.initials: A
authors.lastname: Martínez-Palomo
mesh_terms: D000818:Animals; D061245:Axenic Culture; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000469:parasitology; D003094:Collagen / Q000378:metabolism; D017364:Collagenases / Q000378:metabolism; D006224:Cricetinae; D003594:Cytoplasmic Granules / Q000378:metabolism* / Q000648:ultrastructure*; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000201:enzymology / Q000648:ultrastructure*; D004789:Enzyme Activation; D018093:Gelatinases / Q000378:metabolism; D006790:Host-Parasite Interactions; D008099:Liver / Q000469:parasitology / Q000473:pathology; D008101:Liver Abscess, Amebic / Q000469:parasitology / Q000473:pathology; D008297:Male; D010587:Phagocytosis; D059748:Proteolysis; D013997:Time Factors; D053058:Trophozoites / Q000201:enzymology / Q000648:ultrastructure
chemical_list: D003094:Collagen; D017364:Collagenases; D018093:Gelatinases