A previously unknown factor required for the development of the malaria parasite in the mosquito has now been identified. It is xanthurenic acid - which has been demonstrated to be crucial for the induction of gametogenesis in Plasmodium . As gametogenesis is the first obligatory step in the development of the malaria parasite in the mosquito, this discovery could form the basis of rational new approaches to interrupt malaria transmission.
Plasmodium is transmitted to the mosquito from vertebrate hosts as gametocytes.
These blood-living stages are responsible for the sexual events of the parasite life cycle. Within minutes of ingestion into the bloodmeal, the gametocytes form gametes, which then fuse to form zygotes. It has been known for over 50 years that the pH and temperature of the bloodmeal, in association with unknown factors from the mosquito, play key roles in regulating the induction of gametogenesis. In the 1970s, it was shown that a mosquito extract could stimulate gametogenesis in vitro . This project has also demonstrated the complex interdependency of three gametogenesis-regulating factors in vitro .