GENETIC AND BIOCHEMICAL-ANALYSIS OF DEVELOPMENT IN TOXOPLASMA-GONDII

Toxoplasma gondii has recently come under intense study as a model for intracellular parasitism because it has a number of properties that f acilitate experimental manipulation. Attention is now being turned tow ards understanding the developmental biology of this complex parasite. The differentiation between the two asexual stages, the rapidly growi ng tachyzoites and the more slowly dividing, encysted bradyzoites, is of particular interest. Progression from the former to the latter is i nfluenced by the host's immune response. This paper describes current progress on a number of research fronts, all aimed at understanding th e triggers that push the tachyzoite-bradyzoite equilibrium in one or o ther direction and the changes that occur in gene expression (and ulti mately metabolism and function). Chief among the techniques used for t hese studies are genetics and molecular genetics. Recent progress in t hese areas is described.