More productive in vitro culture of Cryptosporidium parvum for better study of the intra- and extracellular phases

The great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. Due to the models of in vitro culture, new extracellular stages of Cryptosporidium have been demonstrated. The development of these extracellular phases depends on the technique of in vitro culture and on the species and genotype of Cryptosporidium used. Here, we undertake the molecular characterization by polymerase chain reaction-restriction fragment lenght polymorphism of different Cryptosporidium isolates from calves, concluding that all are C. parvum of cattle genotype, although differing in the nucleotide at positions 472 and 498. Using these parasites, modified the in vitro culture technique for HCT-8 cells achieving greater multiplication of parasites. The HCT-8 cell cultures, for which the culture had not been renewed in seven days, were infected with C. parvum sporozoites in RPMI-1640 medium with 10 percent IFBS, CaCl2 and MgCl2 1 mM at pH 7.2. Percentages of cell parasitism were increased with respect to control cultures (71 percent at 48 h vs 14.5 percent), even after two weeks (47 percent vs 1.9 percent). Also, the percentage of extracellular stages augmented (25.3 percent vs 1.1 percent at 96 h). This new model of in vitro culture of C. parvum will enable easier study of the developmental phases of C. parvum in performing new chemotherapeutic assays.

Superoxide dismutase from Trichuris ovis, inhibiton by benzimidazoles and pyrimidine derivatives

Three superoxide dismutase isoenzymes of different cellular location were detected in an homogenate of Thrichuris ovis. Each of these molecular forms was purified by differential centrifugation and precipitation with ammonium sulphate, followed by chromatography on DEAE-cellulose and Sephadex G-75 columns. The activity levels of the two molecular forms detected in the mitochondrial (one cyanide sensitive Cu-Zn-SOD and the other cyanide intensitive Mn-Sod were higher than that of the superoxide dismutase detected in the cytoplasmic fraction (cyanid sensitive Cu-Zn-SOD). All the mollecular forms present evident differences to the SODs contained in the host liver. Molecular mass and some of the physical and chemical aproperties of the enzyme was determined for all three molecular forms. An inhibitory effect on the SOD of the parasite an the host was detected with a series of compounds, some of wich markedly inhibited parasite ensyme but not host enzyme

Glucogeno sintasa en helmintos parasitos: inhibición por benzimidazoles / Glycogen synthetase in helminthics parasites: inhibition by benzimidazoles

Se ha determinado el efecto inhibidor sobre la actividad Glucogeno sintetasa (E.C.2.4.1.11) por parte de cuatro antihelminticos: Albendazol, Mebendazol, Parbendazol y Tiabendazol. Observandose que en todos los casos, es el Parbendazol quien ha demostrado un mayor poder inhibidor sobre la glucógeno sintetasa de Ascaris suum, Fasciola hepatica y Moniezia expansa. El Tiabendazol es el antihelmintico que menor efecto inhibidor ha presentado sobre la enzima en los tres parásitos objeto de nuestro estudio. Con el presente trabajo y otros previstos en la misma linea, se pretende aportar nuevos datos acerca del aún desconocido locus de acción de estos antihelminticos