Cell motility in sporozoites of Cryptosporidium muris.
|Fakulta / Pracoviště MU|
|Popis||Although the motility of cryptosporidian sporozoites is considered as the main mechanism facilitating the host cell invasion, our observations show that motility of C. muris sporozoites is very limited and featureless, and differs from other apicomplexan zoites. As cryptosporidian sporozoites possess a single rhoptry, they have only one attempt for successful attachment to the host cell. Within the host organism, released sporozoites of C. muris rapidly penetrate deeply into the bottom of the pits of the gastric glands to avoid the adverse conditions in the host stomach. In cell cultures, using various media, including those enriched by BSA and vitamins, the activity of freshly released sporozoites decreases very rapidly and after several minutes, sporozoites do not show any signs of vitality. The apical region of invasive sporozoites is obviously prolonged and their three-layered pellicle is smooth lacking any grooves or folds. Using immunofluorescence we were able to obtain myosin labelling, which is considered an essential part of apicomplexan motility motor. Labelling of actin with a specific antibody recognizing the actin in Toxoplasma gondii and Plasmodium falciparum was not successful despite multiple repetitions of staining procedure of C. muris sporozoites. However, immunoblotting assays of sporozoites soluble proteins indicated the presence of actin (42 kDa) in relatively low concentrations. In addition, we were able to amplify by PCR and sequence the C. muris actin gene from genomic DNA. Using the both immunofluorescence and immunoblotting, we were able to detect alfa-tubulin (50 kDa), which represents an elemental component of subpellicular microtubules. Therefore, the currently obtained data support the presence, in C. muris, of basic mechanism of apicomplexan motility that is expected to be based on the orientation of the actomyosin motor by subpellicular microtubules.|