Poster: Cytoskeleton: Structure & Function
Abs #
1121: Effects of ultraviolet irradiation on cell viability and microtubule organization in Nicotiana plumbaginifolia suspension culture.
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Presenter: |
Blume, Ya.B. , cellbio@cellbio.freenet.viaduk.net |
Authors | Blume, Ya.B. (A) Grishchenko, Ye (A) Smertenko, P.S. (B) Zayets, V.N. (A) | | Affiliations: |
(A): Institute of Cell Biol. & Genet. Engrg., National Academy of Science
(B): Institute of Semiconductor Physics, National Academy of Sciences
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Exposure of cells to UV radiation has been shown to lead to a delay in the onset of mitosis. UV radiation induces depolymerization of the microtubules (MTs) in different animal cells. The disruption of MTs is probably due to a combination of direct effect of UV radiation on tubulin dimers and realization of cell apoptotic program. It was shown that UV induces mitotic delay and MT depolymerization in plant protoplasts (Staxen et al., 1993). To develop the experimental investigation of UV irradiation effects on plant cytoskeleton, cell suspension culture of Nicotiana plumbaginifolia was used as model system. UV radiation was supplied by a luminescent lamp TL-12RS (Philips) with maximum of exitation at 305 nm (UV Â) in the range of the UV doses (irradiance x time) 4-24 mmol photons/m2. The different UV doses were obtained by varying the irradiation time. Viability of the cells and MT staining were carried out 0, 24, 48, and 72 h after irradiation. The UV doses employed in the experiments did not affect significantly cell viability in suspension culture during first 24 h after irradiation. The viability decreased more significantly after 48-72 h after its irradiation. UV radiation caused fragmentation of the cortical MTs. At the higher doses the MTs were destabilized, becoming curled instead of having the smooth appearance of those of the non-irradiated cells. There was, however, no difference in their length. Mitotic figures could be observed after 48 h in the control and in cells that had received 4-8 mmol photons/m2, but not in the samples irradiated with the highest doses. There was no difference in the shape of the mitotic spindle in the control cells compared to the irradiated cells. In all samples showing cell division the presence of phragmoplasts was recorded.
