The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform

Zhu Xuen - One of the best experts on this subject based on the ideXlab platform.

  • study on process for synthesis of iso Hexylene Glycol
    Chemical Engineering(China), 2003
    Co-Authors: Zhu Xuen
    Abstract:

    A method for the synthesis of Hexylene Glycol by catalytic hydrogenation from diacetone is presented. The effects of reaction temperature,pressure and time, amount of catalyst and rate of agitation on product yields are discussed.The advanced operating conditions for synthesis of Hexylene Glycol are obtained. The yield of the synthesis can be higher than 90%. The new process is featured by high yield, easy operation, which is convenient for the realizing commercial production.

Changsheng Yang - One of the best experts on this subject based on the ideXlab platform.

Julio Pudles - One of the best experts on this subject based on the ideXlab platform.

  • Cytoskeleton of the unfertilized sea urchin egg.
    Biology of the Cell, 2012
    Co-Authors: G. Foucault, Marie-noëlle Raymond, Julio Pudles
    Abstract:

    : Unfertilized Paracentrotus lividus egg cytoskeleton is prepared by mild, nonionic detergent extraction at 4 degrees C in buffer systems containing either 2-methyl-2,4-pentanediol (Hexylene Glycol) or glycerol. These extractions allow the isolation of cytomatrices that maintain the egg form and are 70-80 micron in diameter. DNase inhibition assays show that actin is in polymerized form in these cytomatrices. Ultrastructural observations reveal that the cytoskeletons are made up essentially of 2 categories of filaments, 7-8-nm and 2-4-nm in diameter, respectively. After heavy meromyosin labelling, short, radiating actin filaments are seen in the cortical region, while longer actin filaments are found in the internal region of these cytomatrices. The 2-4-nm filaments of still unknown biochemical nature are organized in a meshwork. In contrast to results found with fertilized eggs, bundles of actin filaments and microtubules are absent; 8-13-nm filaments are not detected.

  • Dual effect of procaine in sea urchin eggs. Inducer and inhibitor of microtubule assembly.
    Experimental Cell Research, 2004
    Co-Authors: Gérard Coffe, M N Raymond, G. Foucault, Julio Pudles
    Abstract:

    An increase in the amount of cytoplasmic filamentous structures (cytoplasmic matrix and aster) which were recovered after Hexylene Glycol/Triton X-100 treatment of sea urchin eggs (Paracentrotus lividus) activated by 0.2–2.5 mM procaine was observed. At higher activator concentrations, an opposite effect was observed and formation of these cytoplasmic structures was inhibited in the presence of 10 mM procaine. This inhibitory effect was reversed by diluting the drug in the incubation medium. DNase I inhibition assays on egg homogenates which were performed at different time points of the activation process, show that the same amount of actin was induced to polymerize in eggs activated either by 2.5 or 10 mM procaine. However, colchicine-binding assays on the 100000 g particulate fractions of these homogenates show that in eggs activated by 10 mM procaine, in contrast to those activated by 2.5 mM, tubulin polymerization was inhibited and microtubules were disassembled. These results show that the dual effect of procaine in the organization of the egg cytoskeleton appears to be related to its effect on the state of tubulin.

Qian Yang - One of the best experts on this subject based on the ideXlab platform.

Yukihisa Hamaguchi - One of the best experts on this subject based on the ideXlab platform.

  • Change in the Heterogeneous Distribution of Tubulin Isotypes in Mitotic Microtubules of the Sea Urchin Egg by Treatment with Microtubule Depolymerizing or Stabilizing Drugs
    Cell Structure and Function, 2020
    Co-Authors: Takao Arai, Yukihisa Hamaguchi
    Abstract:

    : In the mitotic sea urchin egg, the spindle microtubules were composed of different tubulin isotypes from those of astral microtubules using monoclonal antibodies [Oka et al. (1990) Cell Motil. Cytoskeleton, 16, 239-250]. Three of the antibodies, D2D6, DM1B, and YL1/2, were specific for spindle microtubules, astral microtubules and reactive with both microtubules, respectively. The mitotic sea urchin egg was treated with microtubule depolymerizing (colcemid and nocodazole) and stabilizing (Hexylene Glycol) drugs and change in the heterogeneous distribution of the tubulin isotypes was investigated by the immunofluorescence procedure using these three monoclonal anti-tubulin antibodies. We observed that: (1) the microtubule depolymerizing drugs caused quick depolymerization of most mitotic microtubules, and a small number of spindle microtubules remaining were stained with all three antibodies; (2) Hexylene Glycol induced many microtubules in the mitotic apparatus, which was stained with D2D6 but was not stained with DM1B; (3) Hexylene Glycol also induced a great number of miniasters in the cytoplasm, and they were stained with three antibodies. These results suggest that these drugs altered the distribution of tubulin isotypes in the mitotic microtubules during depolymerization or polymerization within a short time.

  • Division of Polar Bodies Induced by Their Enlargement in the StarfishAsterina pectinifera
    Experimental Cell Research, 1997
    Co-Authors: Tomoaki Saiki, Yukihisa Hamaguchi
    Abstract:

    Abstract The first polar body (FPB), which is formed at the first meiotic division during oogenesis, does not generally divide. We made a hypothesis that the amount of cytoplasm was not sufficient for the FPB to perform cell division, in spite of the same amount of genomes and centrosome as those of the secondary oocyte. To examine this hypothesis, Hexylene Glycol (HG) at a low concentration was applied to oocytes of the starfishAsterina pectiniferaduring the first meiotic division. Hence, FPBs were enlarged in their diameters, some of them divided once, and the division rate increased in proportion as their diameter extended. We further hypothesized that the difference between the second polar body (SPB) and the egg would be only the amount of cytoplasm and that if SPBs were enlarged, they would become eggs. When the secondary oocytes were treated with HG, large SPBs were obtained. Some of them, however, divided, and resultant daughter cells divided moreover, whereas eggs would not cleave unless they were fertilized. We discuss here the reason why the centrosome distributed during maturation division began to function in enlarged PBs.