Microscopic and molecular characterization of ovarian follicle atresia in Rhodnius prolixus Stahl under immune challenge

Marcelo N Medeiros, Isabela B Ramos, Danielle M P Oliveira, Rodrigo Belmonte, Fabio M Gomes, Luciano N Medeiros, Eleonora Kurtenbach, Luciana B Chiarini, Hatisaburo Masuda, Wanderley de Souza, Ednildo A Machado

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9 Citations (Scopus)

Abstract

In this work we characterized the degenerative process of ovarian follicles of the bug Rhodnius prolixus challenged with the non-entomopathogenic fungus Aspergillus niger. An injection of A. niger conidia directly into the hemocoel of adult R. prolixus females at the onset of vitellogenesis caused no effect on host lifespan but elicited a net reduction in egg batch size. Direct inspection of ovaries from the mycosed insects revealed that fungal challenge led to atresia of the vitellogenic follicles. Light microscopy and DAPI staining showed follicle shrinkage, ooplasm alteration and disorganization of the monolayer of follicle cells in the atretic follicles. Transmission electron microscopy of thin sections of follicle epithelium also showed nuclei with condensed chromatin, electron dense mitochondria and large autophagic vacuoles. Occurrence of apoptosis of follicle cells in these follicles was visualized by TUNEL labeling. Resorption of the yolk involved an increase in protease activities (aspartyl and cysteinyl proteases) which were associated with precocious acidification of yolk granules and degradation of yolk protein content. The role of follicle atresia in nonspecific host-pathogen associations and the origin of protease activity that led to yolk resorption are discussed.
Original languageEnglish
Pages (from-to)945-953
Number of pages9
JournalJournal of Insect Physiology
Volume57
Issue number7
Early online date22 Apr 2011
DOIs
Publication statusPublished - Jul 2011

Keywords

  • animals
  • apoptosis
  • aspartic acid proteases
  • Aspergillus niger
  • cysteine proteases
  • female
  • fluorescent dyes
  • follicular atresia
  • in situ nick-end labeling
  • indoles
  • microscopy, electron, transmission
  • rhodnius
  • vitellogenesis

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    Medeiros, M. N., Ramos, I. B., Oliveira, D. M. P., Belmonte, R., Gomes, F. M., Medeiros, L. N., Kurtenbach, E., Chiarini, L. B., Masuda, H., de Souza, W., & Machado, E. A. (2011). Microscopic and molecular characterization of ovarian follicle atresia in Rhodnius prolixus Stahl under immune challenge. Journal of Insect Physiology, 57(7), 945-953. https://doi.org/10.1016/j.jinsphys.2011.04.010