Hiroki Yasuhara

Learn More
Treatment of tobacco BY-2 cells with 20 microM brefeldin A (BFA), which causes disassembly of the Golgi apparatus (Yasuhara et al. 1995), completely inhibited the formation of the cell plate when the treatment was started before the chromosomes had begun to to condense. In cells in which cell-plate formation was inhibited by BFA, the centrifugal development(More)
Treatment with 20 microM brefeldin A (BFA) for 60 min caused the disassembly of the Golgi apparatus in tobacco BY-2 cells, and the effect of BFA was reversible. Connections between Golgi cisternae and the ER were observed in cells that had been treated for 15 min with BFA. BFA applied to cells at metaphase allowed the cells to form aniline blue-positive(More)
Treatment of tobacco BY-2 cells with 10 mM caffeine that was started after the cells had entered the mitotic phase did not completely inhibit the deposition of callose in the cell plate and allowed the centrifugal redistribution of phragmoplast microtubules. On the other hand, when treatment with caffeine was started before the cells entered the mitotic(More)
Bundles of microtubules and cross-bridges between microtubules in the bundles have been observed in phragmoplasts, but proteins responsible for forming the cross-bridges have not been identified. We isolated TMBP200, a novel microtubule bundling polypeptide with an estimated relative molecular mass of about 200,000 from telophase tobacco BY-2 cells.(More)
TMBP200 from tobacco BY-2 cells is a member of the highly conserved family of microtubule-associated proteins that includes Xenopus XMAP215, human TOGp, and Arabidopsis MOR1/GEM1. XMAP215 homologues have an essential role in spindle assembly and function in animals and yeast, but their role in plant mitosis is not fully clarified. Here, we show by(More)
We have studied the effects of three imidazole derivatives, clotrimazole (CLO), ketoconazole (KET) and miconazole (MIC) on the liver microsomal diazepam (DZ) metabolism. In in vitro experiments using rats and human liver microsomes, significant inhibition of CYP3A in terms of DZ-3-hydroxylase activity was observed. The inhibition of DZ metabolism was seen 1(More)
In land plant cells, division planes are precisely predicted by the microtubule preprophase band and cortical actin microfilament pattern called the actin-depleted zone or actin microfilament twin peaks. However, the function of cortical actin microfilament patterning is not clear. In this study, we report that treatment with the inhibitor(More)
Plant nuclei are known to differentiate into various shapes within a single plant. However, little is known about the mechanisms of nuclear morphogenesis. We found that nuclei of tobacco BY-2 cells were highly elongated on long-term treatment with 5 mg l⁻¹ aphidicolin, an inhibitor of DNA polymerase α. In aphidicolin-treated cells, the nuclear length was(More)
Precise division plane determination is essential for plant development. At metaphase, a dense actin microfilament meshwork appears on both sides of the cell center, forming a characteristic cortical actin microfilament twin peak pattern in BY-2 cells. We previously reported a strong correlation between altered cortical actin microfilament patterning and an(More)
  • 1