DGAT2 revealed by the immunogold technique in Arabidopsis thaliana lipid bodies associated with microtubules

The immunogold technique with anti-diacylglycerol acyltransferase 2 (DGAT2) antibody revealed inA. thaliana embryo and root meristematic cells gold particles manifesting the presence of DGAT2 in ER as wellas in lipid bodies. This being so, lipid synthesis could take place both in ER and in the lipid bodies. The presenceof microtubules around the lipid bodies was evidenced under transmission EM. Detection of tubulin around thelipid bodies using the immunogold technique with anti-a-tubulin is in agreement with the above observations.Connection of lipid bodies with microtubules was also detected by us in other plants where they probably participatedin lipid synthesis. A similar phenomenon may take place in A. thaliana.The immunogold technique with anti-diacylglycerol acyltransferase 2 (DGAT2) antibody revealed inA. thaliana embryo and root meristematic cells gold particles manifesting the presence of DGAT2 in ER as wellas in lipid bodies. This being so, lipid synthesis could take place both in ER and in the lipid bodies. The presenceof microtubules around the lipid bodies was evidenced under transmission EM. Detection of tubulin around thelipid bodies using the immunogold technique with anti-a-tubulin is in agreement with the above observations.Connection of lipid bodies with microtubules was also detected by us in other plants where they probably participatedin lipid synthesis. A similar phenomenon may take place in A. thaliana

Inter- and intrachromosomal asynchrony of cell division cycle events in root meristem cells of Allium cepa: possible connection with gradient of cyclin B-like proteins

Alternate treatments of Allium cepa root meristems with hydroxyurea (HU) and caffeine give rise to extremely large and highly elongated cells with atypical images of mitotic divisions, including internuclear asynchrony and an unknown type of interchromosomal asynchrony observed during metaphase-to-anaphase transition. Another type of asynchrony that cannot depend solely on the increased length of cells was observed following long-term incubation of roots with HU. This kind of treatment revealed both cell nuclei entering premature mitosis and, for the first time, an uncommon form of mitotic abnormality manifested in a gradual condensation of chromatin (spanning from interphase to prometaphase). Immunocytochemical study of polykaryotic cells using anti-β tubulin antibodies revealed severe perturbations in the microtubular organization of preprophase bands. Quantitative immunofluorescence measurements of the control cells indicate that the level of cyclin B-like proteins reaches the maximum at the G2 to metaphase transition and then becomes reduced during later stages of mitosis. After long-term incubation with low doses of HU, the amount of cyclin B-like proteins considerably increases, and a significant number of elongated cells show gradients of these proteins spread along successive regions of the perinuclear cytoplasm. It is suggested that there may be a direct link between the effects of HU-mediated deceleration of S- and G2-phases and an enhanced concentration of cyclin B-like proteins. In consequence, the activation of cyclin B-CDK complexes gives rise to an abnormal pattern of premature mitotic chromosome condensation with biphasic nuclear structures having one part of chromatin decondensed, and the other part condensed

Microtubule heterogeneity of <i>Ornithogalum umbellatum</i> ovary epidermal cells: non-stable cortical microtubules and stable lipotubuloid microtubules

Lipotubuloids, structures containing lipid bodies and microtubules, are described in ovary epidermal cells of <i>Ornithogalum umbellatum</i>. Microtubules of lipotubuloids can be fixed in electron microscope fixative containing only buffered OsO<sub>4</sub> or in glutaraldehyde with OsO<sub>4</sub> post-fixation, or in a mixture of OsO<sub>4</sub> and glutaraldehyde [1]. None of these substances fixes cortical microtubules of ovary epidermis of this plant which is characterized by dynamic longitudinal growth. However, cortical microtubules can be fixed with cold methanol according immunocytological methods with the use of <i>b</i>-tubulin antibodies and fluorescein. The existence of cortical microtubules has also been evidenced by EM observations solely after the use of taxol, microtubule stabilizer, and fixation in a glutaraldehyde/OsO<sub>4</sub> mixture. These microtubules mostly lie transversely, sometimes obliquely, and rarely parallel to the cell axis. Staining, using Ruthenium Red and silver hexamine, has revealed that lipotubuloid microtubules surface is covered with polysaccharides. The presumption has been made that the presence of a polysaccharide layer enhances the stability of lipotubuloid microtubules. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 2, 285–290

DGAT2 revealed by the immunogold technique in Arabidopsis thaliana lipid bodies associated with microtubules

The immunogold technique with anti-diacylglycerol acyltransferase 2 (DGAT2) antibody revealed in<br />A. thaliana embryo and root meristematic cells gold particles manifesting the presence of DGAT2 in ER as well<br />as in lipid bodies. This being so, lipid synthesis could take place both in ER and in the lipid bodies. The presence<br />of microtubules around the lipid bodies was evidenced under transmission EM. Detection of tubulin around the<br />lipid bodies using the immunogold technique with anti-a-tubulin is in agreement with the above observations.<br />Connection of lipid bodies with microtubules was also detected by us in other plants where they probably participated<br />in lipid synthesis. A similar phenomenon may take place in A. thaliana.The immunogold technique with anti-diacylglycerol acyltransferase 2 (DGAT2) antibody revealed in<br />A. thaliana embryo and root meristematic cells gold particles manifesting the presence of DGAT2 in ER as well<br />as in lipid bodies. This being so, lipid synthesis could take place both in ER and in the lipid bodies. The presence<br />of microtubules around the lipid bodies was evidenced under transmission EM. Detection of tubulin around the<br />lipid bodies using the immunogold technique with anti-a-tubulin is in agreement with the above observations.<br />Connection of lipid bodies with microtubules was also detected by us in other plants where they probably participated<br />in lipid synthesis. A similar phenomenon may take place in A. thaliana

Microtubule heterogeneity of Ornithogalum umbellatum ovary epidermal cells: non-stable cortical microtubules and stable lipotubuloid microtubules

Lipotubuloids, structures containing lipid bodies and microtubules, are described in ovary epidermalcells of Ornithogalum umbellatum. Microtubules of lipotubuloids can be fixed in electron microscope fixativecontaining only buffered OsO4 or in glutaraldehyde with OsO4 post-fixation, or in a mixture of OsO4 and glutaraldehyde[1]. None of these substances fixes cortical microtubules of ovary epidermis of this plant which ischaracterized by dynamic longitudinal growth. However, cortical microtubules can be fixed with cold methanolaccording immunocytological methods with the use of b-tubulin antibodies and fluorescein. The existence ofcortical microtubules has also been evidenced by EM observations solely after the use of taxol, microtubulestabilizer, and fixation in a glutaraldehyde/OsO4 mixture. These microtubules mostly lie transversely, sometimesobliquely, and rarely parallel to the cell axis. Staining, using Ruthenium Red and silver hexamine, has revealedthat lipotubuloid microtubules surface is covered with polysaccharides. The presumption has been made thatthe presence of a polysaccharide layer enhances the stability of lipotubuloid microtubules