title: Follicular atresia during Dacus oleae oogenesis.
abstract: Programmed cell death, constitutes a common fundamental incident that occurs during oogenesis in a variety of different animals. It plays a significant role in the maturation process of the female gamete and also in the removal of abnormal and superfluous cells at certain checkpoints of development. In the present study, we demonstrate the existence of follicular atresia during mid-oogenesis in the olive fruit fly Dacus oleae (Tephritidae). The number of atretic follicles increases following the age of the fly, suggesting for the presence of an age-susceptible process. The atretic follicles contain nurse cells that exhibit chromatin condensation, DNA fragmentation and actin cytoskeleton alterations, as revealed by propidium iodide staining, TUNEL labeling and phalloidin-FITC staining. Conventional light and electron microscopy disclose that the nurse cell remnants are phagocytosed by the adjacent follicle cells. The follicular epithelium also eliminates the oocyte through phagocytosis, resulting to an egg chamber with no compartmentalized organization. The data presented herein are very similar compared to previous reported results in other Diptera species, strongly suggesting the occurrence of a phylogenetically conserved mechanism of follicular atresia. All these observations also support the notion that mid-oogenesis in D. oleae may be the critical regulation point at which superfluous and defective egg chambers are selectively eliminated before they reach maturity.
authors.affiliation: Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, 15784 Athens, Greece.
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Nezis
authors.forename: Dimitrios J
authors.initials: DJ
authors.lastname: Stravopodis
authors.forename: Lukas H
authors.initials: LH
authors.lastname: Margaritis
authors.forename: Issidora S
authors.initials: IS
authors.lastname: Papassideri
mesh_terms: D000165:Acridine Orange / Q000737:chemistry; D000818:Animals; D004396:Coloring Agents / Q000737:chemistry; D053938:DNA Fragmentation / Q000502:physiology; D005260:Female; D005496:Follicular Atresia / Q000502:physiology*; D020287:In Situ Nick-End Labeling; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D009866:Oogenesis / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology* / Q000648:ultrastructure; D010590:Phalloidine / Q000031:analogs & derivatives / Q000737:chemistry; D011419:Propidium / Q000737:chemistry; D033621:Tephritidae / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D004396:Coloring Agents; C037191:fluorescein isothiocyanate-phalloidin; D010590:Phalloidine; D011419:Propidium; D000165:Acridine Orange