Detection of a proteinase common to epimastigote, trypomastigote and amastigote of different strains of Trypanosoma cruzi.

Trypanosoma cruzi epimastigote lysates presented proteolytic activity both at pH 7.0 (Km = 2.5 mg casein/ml, Km = 12.2 mg hemoglobin/ml) and at pH 3.0 (Km = 2.5 mg hemoglobin/ml). A proteinase was isolated from these lysates by using three different steps: 1) Precipitation at -20 degrees C, pH 4.5, with 80% acetone; 2) Sephadex G200 chromatography and 3)Affinity chromatography on columns of Sepharose 4B coupled to p-aminophenylmercuri-acetate. The isolated proteinase, which is probably an SH-dependent enzyme, was able to hydrolyze hemoglobin at pH 3.0 and both casein and hemoglobin at pH 7., but was unable to hydrolyze the esterase synthetic substrate tested. A single enzyme of molecular weight 60,000 could be detected in purified preparations when analysed by disc gel electrophoresis, crossed immunoelectrophoresis, SDS-polyacrylamide gel electrophoresis and Sephadex chromatography. Antibodies induced by the purified proteinase, shown to be specific for proteinase molecules by line immunoelectrophoresis experiments, reacted with epimastigota of the Y strain and with trypomastigota and amastigota of five different strains tested. Electron microscopy observations of peroxidase labeled preparations indicated that the proteinase could be found at the surface of different forms of the parasite.

Study of the action of some centrally acting drugs on the EEG and on a conditioned avoidance reflex in the rabbit.

A study was carried out on the effect of perphenazine, diazepam, benactyzine, morphine and a new central analgesic, viminol, onboth EEG and behaviour in rabbits with chronically implanted electrodes trained to a conditioned escape reflex. The results obtained are discussed considering the mechanism and site of action of the different drugs: the experimental procedure adopted is recommended to obtain additional informations on the properties of centrally acting drugs.