Histochemical Studies of Succinic Dehydrogenase in Trypanosoma cruzi and Leishmania leproide

Summary Succinic dehydrogenase has been demonstrated histochemically in T. cruzi and L. leproide - leptomonad form. The protozoa were stained for the enzyme with nitro blue tetrazolium in presence of brilliant cresyl blue. Optimal requirements for the reaction have been described. Enzyme activity is indicated by blue deposits of diformazan in granular form in the cytoplasm. The reaction is weak in absence of calcium and bicarbonate and is inhibited by malonate. Spirotrypan had some inhibitory effect on the tetrazolium reaction in T. cruzi both in vitro and in vivo.