ORGANELLAR TARGETING AND EXPRESSION ANALYSIS OF TOXOPLASMA GONDII HSP90 DURING BRADYZOITE DEVELOPMENT

ANGEL, SO; ECHEVERRIA PC

Caxambu

Congreso; XIX MEETING OF THE BRAZILIAN SOCIETY OF PROTOZOOLOGY; 2003

Toxoplasma gondii is an obligate intracellular parasite, member of thephylum Apicomplexa that can infect mammals and birds. In humans, T. gondiiis known to cause transplacental infection that can lead to abortion or severeneonatal malformations and eye disease. Recently, T. gondii has emerged as anopportunistic pathogen of major importance in immunocompromised individuals,frequently as a cause of encephalitis. Infection occurs by oral route, and theparasites diferentiate to the asexual tachyzoite form in the small intestineepitelium. In a few weeks, tachyzoites differentiate to the asexual bradyzoitestage, and generate intracellular latent tissue cysts. The asexual cycle occurs ina large number of warm-blooded animals. It involves an equilibrium betweenthe rapidly dividing tachyzoite and the more slowly dividing bradyzoite. The invivo differentiation to the bradyzoite stage is a stress-related response of T. gondiito environmental conditions such as the inflammatory response of the host tothe tachyzoite stage. The induction of bradyzoite development in vitro has beenassociated to temperature, pH, and other kind of stressors, all known to stimulatethe expression of heat shock proteins (hsps).