IN-VITRO GAMETOCYTE FORMATION IN PLASMODIUM-FALCIPARUM ISOLATES ORIGINATING FROM A SMALL ENDEMIC MALARIOUS AREA AND THEIR DNA PROFILING WITH AN OLIGOMER PROBE

Plasmodium falciparum isolates collected from a small endemic area of perennial transmission varied in their ability to form gametocytes in vitro, an essential determinant in natural transmission of malaria. No t all the collected isolates got established in continuous cultures. I n vitro established isolates multiplied better in continuous flow syst em than in candle jar method. These isolates, in general, show lower r ate of multiplication and higher sexual ability to form gametocytes th an the isolates kept in vitro cultivation in non-malarious areas. Clon al variations within an isolate have been studied with regard to gamet ocyte production. The clones differed extensively in their ability to produce gametocytes; six of them could not form gametocytes in vitro. Genotypic diversity of these isolates and some clones was demonstrated using radiolabelled synthetic 21-oligomer probe, conspicuous restrict ion fragment length polymorphism was observed in isolates. However, th e same probe has been unable to discriminate between phenotypically di stinct gametocyte forming and non-gametocyte forming clones.