Περίληψη:
The effects of aluminium (Al) on dividing root-tip cells of Triticum
turgidum were investigated with tubulin immunolabelling and electron
microscopy. Aluminium affects the mechanisms controlling the
organization of microtubule (MT) cytoskeleton, as well as tubulin
polymerization, and induces the following aberrations in mitotic cells.
(1) It delays the MT disassembly during mitosis, resulting in the
persistence of preprophase MT bands in the late prophase cells, the
presence of prophase spindles in prometaphase cells, and a disturbance
in the shortening of kinetochore MT bundles in anaphase cells. (2) It
interferes with the self-organization process of MTs into bipolar
systems, inhibiting the formation of prophase and metaphase spindles.
(3) Aluminium induces the formation of atypical MT arrays, which in the
immunofluorescent specimens appear as ring-like tubulin aggregations in
the cortical cytoplasm of the preprophase/prophase cells and as
endoplasmic tubulin bundles in prophase and metaphase/anaphase cells;
abnormal preprophase MT bands are assembled, consisting of atypical
cortical and endoplasmic MT bundles, the latter clearly lining the
nuclear envelope on the preprophase MT band plane. (4) It disorders the
chromosome movements carried out by the mitotic spindle. In addition,
after prolonged Al treatments chromatin condensation is inhibited. The
outcome is greatly disturbed organization and function of the mitotic
appartus, as well as inhibition of cells from entering mitosis. This
study shows that the MT cytoskeleton is a target site of Al toxicity in
mitotic root-tip cells of T. turgidum. The possible mechanisms by which
Al exerts its toxicity on MT organization and function are discussed.
Συγγραφείς:
Frantzios, G
Galatis, B
Apostolakos, P
