Genotoxic Effects of Semi-Synthetic Isodillapiole on Oviposition in Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae)

Gene coexpression network during ontogeny in the yellow fever mosquito, Aedes aegypti

BACKGROUND

The behaviors and ontogeny of Aedes aegypti are closely related to the spread of diseases caused by dengue (DENV), chikungunya (CHIKV), Zika (ZIKV), and yellow fever (YFV) viruses. During the life cycle, Ae. aegypti undergoes drastic morphological, metabolic, and functional changes triggered by gene regulation and other molecular mechanisms. Some essential regulatory factors that regulate insect ontogeny have been revealed in other species, but their roles are still poorly investigated in the mosquito.

RESULTS

Our study identified 6 gene modules and their intramodular hub genes that were highly associated with the ontogeny of Ae. aegypti in the constructed network. Those modules were found to be enriched in functional roles related to cuticle development, ATP generation, digestion, immunity, pupation control, lectins, and spermatogenesis. Additionally, digestion-related pathways were activated in the larvae and adult females but suppressed in the pupae. The integrated protein‒protein network also identified cilium-related genes. In addition, we verified that the 6 intramodular hub genes encoding proteins such as EcKinase regulating larval molt were only expressed in the larval stage. Quantitative RT‒PCR of the intramodular hub genes gave similar results as the RNA-Seq expression profile, and most hub genes were ontogeny-specifically expressed.

CONCLUSIONS

The constructed gene coexpression network provides a useful resource for network-based data mining to identify candidate genes for functional studies. Ultimately, these findings will be key in identifying potential molecular targets for disease control.

Genotoxic and mutagenic effects of methyl ether dillapiole on the development of Aedes aegypti (Diptera: Culicidae)

Dillapiole, extracted from Piper aduncum essential oil and its derivatives, has been shown to be a potential alternative to the control of Aedes aegypti, which has become resistant to synthetic insecticides. Methyl ether dillapiole (MED) and temephos (TM) were compared to complement the data on the genotoxicity and developmental changes of Ae. aegypti. Over four generations (G₁ -G₄ ), third stage larvae were treated with MED at 60, 80 and 100 μg/mL and TM at 0.002, 0.005 and 0.007 μg/mL for 4 h. Adult females were separated to estimate oviposition and hatching rates, and total egg length. Over the four generations, a significant reduction was recorded in oviposition and hatching rates, and in mean egg length (Tukey, P < 0.05), compared with the negative control (NC). Cytological slide preparations were done from adult oocytes and larval neuroblasts. The cumulative effects of genotoxic (bridges, budding and nuclear fragmentation) and mutagenic (micronucleus and chromosomal breakage) damage was observed in the neuroblasts and oocytes of exposed mosquitoes. Developmental changes and damage to the genome of MED-treated Ae. aegypti were greater than those caused by TM. Further studies should focus on understanding the effects of the MED molecule on Ae. aegypti.