Four culture lines of Babesia bovis Thai strain were successfully established in this study. The results of the in vitro microtest for their sensitivities to quinuronium sulfate revealed that all the culture lines were similarly drug responsive. The 50% inhibitory concentrations for the four culture lines were found to be within the same range, varying from 1.72x10-6 to 2.43x10-6 g/ml. One resistant line TS-2R selected from the drug-treated culture had an IC50 of 1.71x10-5 g/ml which was 7 times higher than that of its original isolate TS-2.
The expression of a Plasmodium falciparum 41 kDa blood stage antigen (p41) was followed by examining both protein level and aldolase activity in synchronized cultures. The protein and enzymatic levels were low in erythrocytes containing ring forms, and increased markedly with the appearance of trophozoites and young schizonts. The subcellular localization of p41 aldolase was determined using immunoelectron microscopy with rabbit anti-p41 and anti-recombinant p41 antisera. P41 was localized within the cytoplasm of P. falciparum extracellular merozoites, trophozoites and schizonts.
The chromosomal DNA of Sarcocystis gigantea and Sarcocystis muris were digested with NotI and SfiI and characterized in contour-clamped homogeneous electric fields. Under these electric fields, the chromosomal DNA of S. gigantea and S. muris showed different electrophoretic mobilities. Therefore, it appears that this technique may be useful in future studies on the differentiation of Sarcocystis species. The results of NotI and SfiI digestion of S. muris chromosomes suggested that there is an absence of a significant number of recognition sites for these two enzymes in the genome of S. muris. The addition of the sizes of 15 SfiI fragments of S. gigantea DNA suggested that the S. gigantea genome is larger than 14 mb.
A battery of monoclonal antibodies were produced in mice against Theileria annulata-infected cells. Two of these antibodies (IgM and IgG1) reacted specifically with the surface membrane of the infected cells but not with Con A-stimulated or unstimulated bovine peripheral blood lymphocytes (PBL). The antibodies could stain also clones which were derived from the cell lines tested in the present study. Similarly, they reacted with T. annulata-infected but not with uninfected sheep PBL. After removal of the parasites by treating the infected cells with the anti-theilerial drug buparvaquone, the antibodies were no
more able to bind to the cells.