title: Ultrastructural changes in the follicular epithelium of Ceratophrys cranwelli previtellogenic oocytes.
abstract: In this work we carried out ultrastructural, autoradiographic and biochemical analyses of the follicular epithelium during C. cranwelli previtellogenesis. This study revealed that the follicular epithelium in early previtellogenesis is constituted of a single layer of squamous homogeneous cells. During mid-previtellogenesis two types of cells develop: dark cells and clear cells. The follicular dark cells are actively involved in the synthesis of RNA, which is transferred to the oocyte through the interface. In late previtellogenesis the dark cells show apoptotic characteristics such as chromatin condensation, DNA fragmentation and cytoplasm shrinkage. This process forms apoptotic bodies that seem to be engulfed by the oocyte. Our results show evidence that, during mid- and late C. cranwelli previtellogenesis, the follicular epithelium undergoes remodelling processes interacting with the oocyte.
authors.affiliation: Departamento de Biología del Desarrollo, Instituto Superior de Investigaciones Biológicas, Consejo Nacional de Investigaciones Científicas y Técnicas y Universidad Nacional de Tucumán, Chacabuco 461, 4000, San Miguel de Tucumán, Tucumán, Argentina.
authors.forename: E I
authors.initials: EI
authors.lastname: Villecco
authors.forename: M E
authors.initials: ME
authors.lastname: Mónaco
authors.forename: S S
authors.initials: SS
authors.lastname: Sánchez
mesh_terms: D000818:Animals; D001001:Anura; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D046529:Microscopy, Electron, Transmission; D009865:Oocytes / Q000648:ultrastructure*; D006080:Ovarian Follicle / Q000648:ultrastructure*; D014818:Vitellogenesis