How Eggs of the Zika-carrying Mosquito Survive Desiccation Identification of Metabolic Pathway Points to New Control Opportunities
Published:19 Nov.2023    Source:PLOS

Cells are made mostly of water, and desiccation is a potentially fatal event for any organism, since the structures of many proteins and other cellular molecules are dependent on adequate hydration. While many types of microbes have evolved mechanisms to survive drying out, only a few animals have. Among them is the mosquito Aedes aegypti, the carrier of a variety of viral diseases, including, Zika, dengue, yellow fever, and Chikungunya. Originally found in North Africa, Aedes aegypti has expanded globally, and is now a threat in warm, moist regions throughout the world.


Aedes eggs require from 48 to 72 hours to hatch into larvae, and that eggs must be at least 15 hours old to survive desiccation; eggs that were dried out before this stage failed to hatch when rehydrated. They then compared the proteomes of viable eggs that had and had not been desiccated, and found multiple major changes in metabolic pathways within the desiccated eggs. These included increases in the levels of those enzymes in the tricarboxylic acid (Krebs) cycle that promote lipid metabolism, and a decrease in enzymes of glycolysis and ATP-producing parts of the TCA cycle, which together shunted cellular metabolism toward the production and use of fatty acids.


The findings find that given the importance of Ae. aegypti as a primary vector for numerous viral diseases that affect nearly half the world's populationas well as the rapid geographical expansion of this mosquito vector, these results provide a foundation for reducing Aedes egg survival and global spread. Additionally, some of the specific inhibitors described here that reduce desiccation resistance in Ae. aegypti eggs, as well as new ones affecting other steps in the egg desiccation tolerance pathway, may prove useful as vector-control agents.