Culex quinquefasciatus vitellogenesis: morphological and biochemical aspects

Memórias do Instituto Oswaldo Cruz

André F Cardoso¹  Renato L Cres¹  Alexandre S Moura¹  Fábio De Almeida¹  A Tania Bijovsky¹ 

[1] ,Universidade de São Paulo Instituto de Ciências Biomédicas Departamento de ParasitologiaSão Paulo SP ,Brasil

关键词: Culex quinquefasciatus;    vitellogenesis;    immunolabelling;    morphology;    fat body;    ovary;   

DOI  :  10.1590/S0074-02762010000300003

来源: SciELO

【 摘 要 】

The vitellogenic process in Culex quinquefasciatus, which is triggered by a blood meal, involves the synthesis, distribution and storage of the nutrients necessary for embryo development. The fat body of an adult female Cx. quinquefasciatus revealed two cell types: large trophocytes and small, eosinophilic, "oenocyte-like" cells, which show no morphological changes throughout the gonotrophic cycle. Trophocytes, which only begin to synthesise vitellogenin (Vg) 12 h post-blood meal (PBM), undergo a series of morphological changes following engorgement. These changes include the expansion of the rough endoplasmic reticulum (RER) and Golgi complex, which are later destroyed by autophagosomes. At 84 h PBM, trophocytes return to their pre-engorgement morphology. The ovarian follicles of non-blood-fed Cx. quinquefasciatus contain a cluster of eight undifferentiated cells surrounded by follicular epithelium. After engorgement, the oocyte membrane facing the perioocytic space increases its absorptive surface by microvilli development; large amounts of Vg and lipids are stored between 24 and 48 h PBM. Along with yolk storage in the oocyte, follicular cells exhibit the development of RER cisternae and electron-dense granules begin to fill the perioocytic space, possibly giving rise to endochorion. Later in the gonotrophic cycle, electron-dense vesicles, which are possible exochorion precursors, fuse at the apical membrane of follicular cells. This fusion is followed by follicular cell degeneration.

【 授权许可】

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