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

Research output: Contribution to journalArticle

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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

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Rhodnius
follicular atresia
Rhodnius prolixus
Ovarian Follicle
Aspergillus niger
ovarian follicles
Peptide Hydrolases
proteinases
resorption
Vitellogenesis
Aspartic Acid Proteases
Egg Proteins
Fungal Spores
In Situ Nick-End Labeling
Vacuoles
Transmission Electron Microscopy
Chromatin
Ovum
Insects
Microscopy

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

Cite this

Medeiros, M. N., Ramos, I. B., Oliveira, D. M. P., Belmonte, R., Gomes, F. M., Medeiros, L. N., ... 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

Microscopic and molecular characterization of ovarian follicle atresia in Rhodnius prolixus Stahl under immune challenge. / Medeiros, Marcelo N; Ramos, Isabela B; Oliveira, Danielle M P; Belmonte, Rodrigo; Gomes, Fabio M; Medeiros, Luciano N; Kurtenbach, Eleonora; Chiarini, Luciana B; Masuda, Hatisaburo; de Souza, Wanderley; Machado, Ednildo A.

In: Journal of Insect Physiology, Vol. 57, No. 7, 07.2011, p. 945-953.

Research output: Contribution to journalArticle

Medeiros, MN, Ramos, IB, Oliveira, DMP, Belmonte, R, Gomes, FM, Medeiros, LN, Kurtenbach, E, Chiarini, LB, Masuda, H, de Souza, W & Machado, EA 2011, 'Microscopic and molecular characterization of ovarian follicle atresia in Rhodnius prolixus Stahl under immune challenge', Journal of Insect Physiology, vol. 57, no. 7, pp. 945-953. https://doi.org/10.1016/j.jinsphys.2011.04.010
Medeiros, Marcelo N ; Ramos, Isabela B ; Oliveira, Danielle M P ; Belmonte, Rodrigo ; Gomes, Fabio M ; Medeiros, Luciano N ; Kurtenbach, Eleonora ; Chiarini, Luciana B ; Masuda, Hatisaburo ; de Souza, Wanderley ; Machado, Ednildo A. / Microscopic and molecular characterization of ovarian follicle atresia in Rhodnius prolixus Stahl under immune challenge. In: Journal of Insect Physiology. 2011 ; Vol. 57, No. 7. pp. 945-953.
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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.",
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AU - Medeiros, Marcelo N

AU - Ramos, Isabela B

AU - Oliveira, Danielle M P

AU - Belmonte, Rodrigo

AU - Gomes, Fabio M

AU - Medeiros, Luciano N

AU - Kurtenbach, Eleonora

AU - Chiarini, Luciana B

AU - Masuda, Hatisaburo

AU - de Souza, Wanderley

AU - Machado, Ednildo A

N1 - Copyright © 2011 Elsevier Ltd. All rights reserved.

PY - 2011/7

Y1 - 2011/7

N2 - 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.

AB - 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.

KW - animals

KW - apoptosis

KW - aspartic acid proteases

KW - Aspergillus niger

KW - cysteine proteases

KW - female

KW - fluorescent dyes

KW - follicular atresia

KW - in situ nick-end labeling

KW - indoles

KW - microscopy, electron, transmission

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KW - vitellogenesis

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