The Effect of Plasmodium berghei Infection on Mice Infected with Low-virulent Strains of Trypanosoma cruzi or Leishmania donovani

Malaria is considered to induce immunodepression in host-animals and to increase susceptibility to concurrent infection. Using this phenomenon, we attempted to produce apparently severer infection of Trypanosoma cruzi or Leishmania donovani by low-virulent strains which had been maintained in culture. Plasmodium berghei was inoculated into mice before or after T. cruzi or L. donovani infection. In general, P. berghei infection was shown not to enhance T. cruzi and L. donovani infection with low-virulent strains except for the prolongation of infection by a specific strain of T. cruzi

An Observation of the Transitional Forms between Trypomastigote and Amastigote of Trypanosoma cruzi by Scanning Electronmicroscopy

The transformation process between the trypomastigote and the amastigote was studied by Scanning Electronmicroscopy (SEM). The exclusive process from the trypomastigote to the amastigote was accomplished by incubating trypomastigotes in LIT medium while that from the amastigote to the trypomastigote, by rupturing parasitized fibroblasts after removal of free parasites from the fibroblast cultures infected with T. cruzi. Principally, the former process was initiated by twisting and folding of the parasite body, and the latter, by elongation of the body

Influence of Mannose and Its Derivatives on the Growth of Trypanosoma brucei gambiense in vitro

In the previous experiment mannose specifically inhibited the growth of blood trypomastigotes of Trypanosoma brucei gambiense in vitro over new born mouse brain cells. On the search of its mode of action, effect of mannose derivatives and other monosaccharides on the growth of trypanosomes both on feeder layer and feeder layer free systems was assayed. Different concentrations of each of the monosaccharides and mannose derivatives were added into culture media and used for the cultivation of trypanosomes. Most of the monosaccharides and mannose derivatives tested had no pronounced effect on the growth of the parasites, except α-D-(+)-mannose and 2-Deoxy-D-glucose which specifically inhibited the growth of bloodstream forms on feeder layer and feeder layer free cultures. Furthermore, transmission electron microscopy revealed denaturation of glycosomes, nuclei and kinetoplasts in those parasites cultured in medium containing α-D-(+)-mannose or 2-Deoxy-D-glucose. Nevertheless, surface coat, cell membrane and subpellicular microtubules were intact. Possible mode of action of mannose and 2-Deoxy-D-glucose is discussed