绵羊卵泡液和次黄嘌呤对卵母细胞体外减数分裂的影响

目的 利用在培养液中添加绵羊卵泡液和次黄嘌呤 ,抑制卵母细胞GVBD发生 ,延长转录活性 ,从而使卵母细胞真正成熟 ,提高胚胎质量及生产效率。方法 利用体外成熟技术对有屠宰采集的绵羊卵母细胞进行培养 ,培养液中添加卵泡液及次黄嘌呤 ,检查成熟效果。结果 将卵母细胞培养在 5 0 %和 10 0 %的卵泡液中 ,2 4h后处于GV期的卵母细胞分别为 19% (8 4 2 )和 33 3% (13 39)。在含有 4mmol L次黄嘌呤的培养液中 ,2 4h后有2 1 6 % (16 74 )的卵母细胞处GV期 ,而对照组中只有 6 % (3 5 0 ) ,经过次黄嘌呤处理的卵母细胞多数都停滞于PⅠ期(44 6 % ,33 74 )。在 4mmol L次黄嘌呤培养液中添加FSH并未使受到抑制的卵母细胞诱导成熟。结论 卵泡液和次黄嘌呤只能在有限的程度上抑制减数分裂的重新启动 ,并对减数分裂的全过程都有影响 ,这种影响程度与抑制因子的浓度相关 ,存在明显的剂量效应。

Meiotic Behavior of 1BL/1RS Translocation Chromosome and Alien Chromosome in Two Tri-genera Hybrids

The behavior of wheat-rye translocation chromosome and alien chromosome including Thinopyrum and Haynaldia chromosome at meiosis was investigated in two hybrids by fluorescence in situ hybridization (FISH). Misdivision of translocation chromosome at anaphase I and rye chromatin micronucleus at tetrad stage were observed, A plant with one normal 1BL/1RS translocation chromosome and one 1BL/1RS translocation chromosome deleted about 1/3 of rye chromosome arm in length was identified. One plant with wheat-Thinopyrum non-Robertson translocation chromosome was also detected in the F-2 population of Yi4212 x Yi4095. That could be the results of unequal misdivision of wheat-rye 1BL/1RS translocation chromosome and Thinopyrum chromosome during meiosis. No interaction between translocation chromosome and alien chromosome at meiosis was supported by the data of the distribution frequencies of translocation chromosome and Thinopyrum or Haynaldia chromosome in the progeny of two hybrids. The results may be useful to cultivate new germplasms with different length of rye 1R short arm and wheat-alien non-Robertson translocation tines under wheat background.

Stage-specific appearance of cytoplasmic microtubules around the surviving nuclei during the third prezygotic division of Paramecium

There are six micronuclear divisions during conjugation of Paramecium caudatum： three prezygotic and three postzygotic divisions. Four haploid nuclei are formed during the first two meiotic prezygotic divisions. Usually only one meiotic product is located in the paroral cone （PC） region at the completion of meiosis, which survives and divides mitotically to complete the third prezygotic division to yield a stationary and a migratory pronucleus. The remaining three located outside of the PC degenerate. The migratory pronuclei are then exchanged between two conjugants and fuse with the stationary pronuclei to form synkarya, which undergo three successive divisions （postzygotic divisions）. However, little is known about the surviving mechanism of the PC nuclei. In the current study, stage-specific appearance of cytoplasmic microtubules （cMTs） was indicated during the third prezygotic division by immunofluorescence labeling with anti-alpha tubulin antibodies surrounding the surviving nuclei, including the PC nuclei and the two types of prospective pronuclei. This suggested that cMTs were involved in the formation of a physical barrier, whose function may relate to sequestering and protecting the surviving nuclei from the major cytoplasm, where degeneration of extra-meiotic products occurs, another important nuclear event during the third prezygotic division.

Dynamic Changes of β Tubulin during the Resumption of Meiosis of Mouse Oocyte

Morphological changes of tubulin during the resumption of meiosis in both mouse oocyte and fertilized egg were revealed by indirect immunofluorescent marking with monoclonal antibody against β tubulin. During germinal vesicle period (GV), tubulin was found to be distributed around the GV menibrane. With the disruption of GV membrane, microtubule complexes (MTCs) appeared in cytoplasm, first around GV membrane later to spread to other portions as well. Quantitative difference was noted among different oocytes. MTCs coexisted with spindlesformed by prometaphase tubulin, while metaphase tubulin polymerized into spindles and anaphase and telophase tubulin was concentrated in the two poles of the meiotic apparatus and the midbody. In egg arrested in the 2nd metaphase, whether maturing in vitro or vivo, all the tubulin went to form spindles with no MTCs left in the cytoplasm. After fertilization in vitro,MTCs reappeared in the egg cytoplasm activated by sperms while no MTCs could be revealed in cytoplasm after formation of pronucleus. As demonstrated by this experiment,cytoplasmic tubulin in eggs are polymerized chiefly into two forms: the star-shaped MTCs and the spindle.Cytoplasmic MTCs are the structure newly formed when the 1st and 2nd oocytes resumed meiosis. With colchicine disrupting the polymerization of tubulin, the maternal chromosomes,instead of orderly arrangement and orderly separation, either formed disordered mass or were divided into multiple chromatin masses. However, the penetration of sperm into egg, and decondensation and formation of pronuclei were not affected.