Histochemieal Observations on the Sarcocystis fusiformis Cysts in Ox Hearts

Summary The Sarcocystis fusiformis cysts parasiting the myocardium of 5 adult oxen were mainly studied throughout histoenzymologic techniques. Several cysts were found at different levels of the muscular fibers, including those of the impulse-conducting system. The cystozoites showed the presence of RNA and neutral mucopolysaccharides but contained no glycogen either lipidie material. These cells resulted devoid of the following enzymes: ITDPG-GT, phosphorylases; F-1,6-PA, F-1,6-P Ald, ADH, ATPases, α -GPDH, β -OHBDH, nonspecific esterase, alkaline phosphatase, acid phosphatase, alanyl aminopeptidase, leucine aminopeptidase, cholinesterase and MAO. The reaction of the cystozoites was weak to 6-PGDH, MDH and GDH; moderate to LDH, cis-aconitase and G-6-PDH; strong to NADPH 2 -TR, ICDH and cytochrome oxidase and very strong to G-6-PA and NADH 2 -TR. The SDH reactivity was weak in some sarcocystis but strong in several other ones. The 5-nucleotidase reactivity resulted moderate to strong. There ware found no inflammatory reactions around the Sarcocystis and the enzymatic reactivity of the muscle fibers near to the cysts was not different from that of the apparently normal fibers. It is passible that the Sarcocystis obtain glucose and products of the adenilic acid catabolism from the parasited fibers. Beside its energetic power the glucose probably plays a role in the synthesis of neutral mucopolysaccharides and RNA (throughout the enzymes of the pentose shunt). It is suggested that the neutral mucopolysaccharides interfer with the origin of the parasite membrane and thus exert a protective and an antigenic activity as well.