RESUMO
Haematophagous insects are frequently carriers of parasitic diseases, including malaria. The mosquito Anopheles gambiae is the major vector of malaria in sub-Saharan Africa and is thus responsible for thousands of deaths daily. Although the role of olfaction in A. gambiae host detection has been demonstrated, little is known about the combinations of ligands and odorant binding proteins (OBPs) that can produce specific odor-related responses in vivo. We identified a ligand, indole, for an A. gambiae odorant binding protein, AgamOBP1, modeled the interaction in silico and confirmed the interaction using biochemical assays. RNAi-mediated gene silencing coupled with electrophysiological analyses confirmed that AgamOBP1 binds indole in A. gambiae and that the antennal receptor cells do not respond to indole in the absence of AgamOBP1. This case represents the first documented instance of a specific A. gambiae OBP-ligand pairing combination, demonstrates the significance of OBPs in odor recognition, and can be expanded to the identification of other ligands for OBPs of Anopheles and other medically important insects.
Assuntos
Anopheles/metabolismo , Indóis/metabolismo , Receptores Odorantes/metabolismo , Animais , Eletrofisiologia/métodos , Feminino , Indóis/química , Ligantes , Masculino , Modelos Biológicos , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , Proteínas Recombinantes/metabolismo , Fatores Sexuais , Fatores de TempoRESUMO
Chromosome length in Drosophila is maintained by targeted transposition of three non-long terminal repeat retrotransposons, HeT-A, TART, and TAHRE, to the chromosome ends. The length and composition of these retrotransposon arrays can vary significantly between chromosome tips and between fly stocks, but the significance and consequences of these length differences are not understood. A dominant genetic factor, Tel, has been described, which causes a severalfold elongation of the retrotransposon arrays at all telomeres. We used this strain to assess possible affects of extended telomeres on the organism. While we found no effect on life span of the adults, we could demonstrate a correlation between long telomeres and reduced fertility and fecundity in individual females, which is also reflected in abnormal oocyte development.
