Investigation of factors affecting the production of gametocytes in an Indian isolate.

The fundamental requirement of every gametocytocidal drug screening assay is the sufficient numbers of healthy and viable gametocytes. The number of in vitro gametocytes grossly depends on the genetic capacity of parasites to produce gametocytes and on various environmental factors that are not precisely elucidated. In the present study, we tested multiple environmental factors that are reported, hypothesized, or predicted to influence gametocyte numbers. We observed that hypoxanthine and the use of freshly drawn human blood significantly enhance gametocytemia ( < 0.05) in vitro. However, other tested factors did not significantly affect gametocytemia. The addition of -acetyl glucosamine to the culture enriched the gametocytes but d-sorbitol (5% v/v) in amounts and duration of incubation tested was unable to do so without negatively affecting the maturity and health of the gametocytes. Although the in vitro gametocyte production depends on the genetic capability of the parasite strain tested, various environmental factors also control the ability of the strain to produce gametocytes up to a certain extent. This is the first study testing the role of various environmental factors that might affect the gametocyte development in a gametocyte producing strain. The results presented herein will help in the optimization of gametocyte production procedures for various gametocytocidal drug screening assays.