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Growth of isolated amastigotes of Trypanosoma cruzi in cell-free medium
Abstract:
Amastigotes of Trypanosoma cruzi were purified from overlays of infected Vero cell cultures by centrifugation over a discontinuous gradient of metrizamide. Pure amastigote preparations were usually recovered from the pellet under the layer of specific gravity 1.086. The isolated amastigotes grew in cell-free ML-15HA medium. Growth rate for the different strains of T. cruzi were in the order Y greater than Tulahuen greater than CL. The generation time of amastigotes in ML-15HA medium was 16.8, 18.0 and 26.4 h for the Y, Tulahuen, and CL strains, respectively, in the presence of 5% CO2, and 16.8, 31.2, and 36.4 h, respectively, in the absence of CO2. Intracellular amastigotes did not differ ultrastructurally from amastigotes from either the density-gradient fractionation or culture in cell-free medium.
Insights
Researchers purified Trypanosoma cruzi amastigotes for cell-free culture. Different strains showed varying growth rates, with strain Y growing fastest, offering insights into parasite cultivation for Chagas disease research.
Area of Science:
- Parasitology
- Cell Biology
- Molecular Biology
Background:
- Trypanosoma cruzi amastigotes are the intracellular form of the parasite responsible for Chagas disease.
- Culturing amastigotes in vitro is crucial for studying their biology and for drug development.
- Previous methods for isolating and culturing amastigotes have limitations.
Purpose of the Study:
- To establish a reliable method for purifying Trypanosoma cruzi amastigotes.
- To evaluate the in vitro growth characteristics of different T. cruzi strains in a cell-free medium.
- To compare the ultrastructure of purified and cultured amastigotes with intracellular amastigotes.
Main Methods:
- Purification of T. cruzi amastigotes from infected Vero cell cultures using metrizamide density gradient centrifugation.
- Cultivation of isolated amastigotes in cell-free ML-15HA medium.
- Assessment of amastigote growth rates and generation times under different CO2 conditions.
- Ultrastructural analysis using electron microscopy.
Main Results:
- Pure amastigote preparations were successfully obtained using metrizamide gradients.
- Isolated amastigotes demonstrated growth in cell-free ML-15HA medium.
- Growth rates varied among T. cruzi strains: Y > Tulahuen > CL.
- Generation times were influenced by the presence or absence of CO2, with faster growth observed in its presence.
- Ultrastructural examination revealed no significant differences between intracellular, density-gradient fractionated, and cell-free cultured amastigotes.
Conclusions:
- Metrizamide density gradient centrifugation is an effective method for purifying T. cruzi amastigotes.
- Cell-free culture of T. cruzi amastigotes is feasible and allows for strain-specific growth rate determination.
- The established method provides a valuable tool for studying T. cruzi biology and for screening anti-parasitic compounds.
- Maintaining consistent ultrastructural integrity supports the validity of cell-free culture models for T. cruzi research.