Vesicular ATPase-overexpressing cells determine the distribution of malaria parasite oocysts on the midguts of mosquitoes

In Plasmodium-infected mosquitoes, oocysts are preferentially located at th e posterior half of the posterior midgut, Because mosquitoes rest verticall y after feeding, the effect of gravity on the ingested blood has been propo sed as the cause of such a biased distribution. In this paper, we examined the oocyst distribution on the midguts of mosquitoes that were continuously rotated to nullify the effect of gravity and found that the typical patter n of oocyst distribution did not change, Invasion of the midgut epithelium by ookinetes was similarly found to be biased toward the posterior part of the posterior midgut, We examined whether the distribution of oocysts depen ds on the distribution of vesicular ATPase (V-ATPase)-overexpressing cells that Plasmodium ookinetes preferentially use to cross the midgut epithelium . An antiserum raised against recombinant Aedes aegypti V-ATPase B subunit indicated that the majority of VATPase-overexpressing cells in Ae. aegypti and Anopheles gambiae are localized at the posterior part of the posterior midgut, We propose that the typical distribution of oocysts on the mosquito midgut is attributable to the presence and the spatial distribution of the V-ATPase-overexpressing cells in the midgut epithelium.