[Structure and biology of Toxoplasma gondii bradyzoites].

Tachyzoite-bradyzoite interconversion is one characteristic feature of Toxoplasma gondii. Although highly similar in structure, tachyzoite and bradyzoite differ by the relative amount of certain organelles and by specific surface or cytoplasmic molecules. Differences in structure and contents also exist between parasitophorous vacuoles and cysts. Using stage specific markers, it was shown the quickness of stage switching in vivo as well as in vitro, together with the occurrence of intermediate stages. Regulatory mechanisms of interconversion remain unknown. However, stress or inhibition of the mitochondrial metabolism of the parasite trigger bradyzoite formation.