Protistology • 14 (1), 38–44 (2020) |
The role of cytoskeleton in the ecdysis of the dinoflagellate Prorocentrum minimum |
Vera Kalinina, Mariia Berdieva, and Olga Matantseva Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia | Submitted March 19, 2020 | Accepted April 14, 2020 | Summary Actin filaments (actomyosin system) and microtubules form highly organized cytoskeleton structures in unicellular organisms, in particular, in dinoflagellates. The cytoskeleton organization of Prorocentrum minimum (Pavillard) Schiller, a bloom forming species, differs from that of most other studied dinoflagellates. While the cortical microtubules are absent, a dense layer of actin filaments is located beneath the cell covering. A previous study has shown, that cytoskeleton likely plays an essential role in the ecdysis, the process of cell covering reorganization including shedding of the plasma membrane, outer amphiesmal vesicle membranes and thecal plates, of P. minimum. In this study, the involvement of cytoskeleton in the ecdysis process was investigated using specific drugs influencing cytoskeleton arrangement and functioning. P. minimum cells were treated with cytochalasin D, 2,3-butanedione monoxime (BDM) or nocodazole, and ecdysis was induced by centrifugation, a potent ecdysis trigger. The application of drugs significantly affected the rate of ecdysis induced by centrifugation. Cytochalasin D, an inhibitor of actin polymerization, impaired the last step of ecdysis, i.e. leaving the old thecal plates. BDM, a myosin function inhibitor, and nocodazole, a microtubule-disrupting agent, delayed this process, but did not inhibit it. Taken together, our data suggest that in P. minimum the cortical actin is a crucial cytoskeleton element that is required for the final step of the ecdysis process. Apparently, it may enable opening of the old thecal plates, and squeezing of the ecdysing cell between them.
Key words: 2,3-butanedione monoxime, cytochalasin D, cytoskeleton, ecdysis, nocodazole, Prorocentrum minimum
Address for correspondence: Vera Kalinina. Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg 194064, Russia; e-mail: verakamakalinina@gmail.com |
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