Abstract
Neospora caninum, Toxoplasma gondii and Eimeria bovis are coccidian parasites of veterinary importance. Tachyzoites of N. caninum and T. gondii and sporozoites of E. bovis are able to invade and replicate in endothelial cells in vivo and in vitro. As it holds true for all eukaryotic cells, the survival of parasitized host cells and the parasites themselves should be dependent on ion balances, especially on extra- and intracellular calcium concentrations. Addition of the calcium ionophore A23187 reliably did release merozoites from mature N. caninum and T. gondii meronts grown in cultured primary bovine umbilical vein endothelial cells (BUVEC). Extent and time course of merozoite release depended on both, maturity of the meronts and concentration of the calcium ionophore. Attempts, however, to achieve synchronous release of merozoites from E. bovis first generation meronts by ionophore treatment failed, suggesting a different biological behaviour of this parasite. According to microscopical observations, the quite variable time of E. bovis macromeront maturation and a hampered merozoite exit owing to dense parasite-induced cytoskeleton elements surrounding the meront may be a reason for the lack of inducible synchronous release.
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Abbreviations
- BUVEC:
-
bovine umbilical vein endothelial cells
- DMSO:
-
dimethyl sulfoxid (methylsulfinylmethane)
- ECGM:
-
endothelial cell growth medium
- p. i.:
-
post infection
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Video 1
Release of E. bovis merozoites from a mature first generation meront in a BUVEC monolayer. The video is provided as “mpg” in a Video-CD compatible MPEG1-format. The scene is shown in double speed. (MPG 4.26 MB)
Video 2
Release of N. caninum tachyzoites from mature meronts grown in bovine endothelial cells. The Video is provided as “mpg” in a Video-CD compatible MPEG1-format. The scene is shown in double speed. (MPG 8 MB)
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Behrendt, J.H., Taubert, A., Zahner, H. et al. Studies on synchronous egress of coccidian parasites (Neospora caninum, Toxoplasma gondii, Eimeria bovis) from bovine endothelial host cells mediated by calcium ionophore A23187. Vet Res Commun 32, 325–332 (2008). https://doi.org/10.1007/s11259-007-9033-7
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DOI: https://doi.org/10.1007/s11259-007-9033-7