不同采卵方法及卵巢所处性周期阶段对绵羊卵母细胞体外成熟的影响

本试验主要从采集方法和性周期阶段2方面对绵羊卵母细胞体外成熟的影响进行了探讨。结果表明：不同采卵方法的采卵效果存在差异，卵裂率切割法显著高于抽吸法(27.9%，49.5%；P<0.05)；A、B级卵母细胞成熟率极显著高于C级(75.3%，64.4%，29.1%，P<0.01)，卵裂率A、B级均显著高于C级(42.5%，35.8%，16.0%，P<0.05)；从卵泡期和黄体期卵巢采集到的卵母细胞的体外成熟率和卵裂率分别为66.7%、62.9%；38.2%、34.4%，没有显著差异 (P>0.05)。     

miRNA在哺乳动物配子发生中的作用研究进展

哺乳动物配子发生的基因表达调控包括编码基因的阶段特异性表达调控及非编码基因的转录和转录后水平调控。微小RNA(microRNA, miRNA)作为一类小的非编码RNA, 通过识别靶基因非翻译区的结合位点, 导致mRNA降解或者蛋白质翻译抑制, 从而在转录后水平发挥调控作用。近年来, miRNA在哺乳动物生殖活动中的作用逐渐被揭示, 越来越多的研究表明, miRNA在哺乳动物精子发生、精子成熟、卵母细胞成熟、卵泡发育及早期胚胎发育等过程中都发挥着重要的调节作用, 其可通过调节支持细胞的增殖和凋亡或精原细胞、精母细胞及精细胞的细胞周期进程, 在精子发生的不同阶段发挥间接或直接调控作用, 也可通过调节卵母细胞、卵丘细胞以及颗粒细胞的增殖、凋亡、激素合成和细胞间作用, 对卵母细胞的发育和成熟过程进行调控。作者主要介绍了在哺乳动物配子发生过程中, miRNA的细胞和阶段特异性表达及其对靶基因的调节作用, 以期为深入研究哺乳动物配子发生的调控机制提供参考。     

柠檬苦素对小鼠卵母细胞体外成熟及其体外受精胚胎发育的影响

【目的】研究柠檬苦素(limonin,Lim)对小鼠卵母细胞体外成熟(IVM)及后续体外受精(IVF)胚胎发育潜能的影响,旨在为体外成熟培养系统的优化提供参考。【方法】在小鼠体外成熟培养液中添加不同浓度的Lim(0、10、20、50 μmol/L),成熟培养12 h后统计小鼠卵母细胞第一极体(PBI)排出率,筛选体外成熟培养液中添加Lim的最适浓度;在体外成熟培养液中添加最适浓度的Lim,以0 μmol/L Lim为对照组,成熟培养12 h,通过免疫荧光染色检测活性氧(ROS)、谷胱甘肽(GSH)以及线粒体膜电位(MMP)水平;通过实时荧光定量PCR检测卵母细胞抗氧化及凋亡相关基因的mRNA表达水平。将最适Lim组及对照组卵母细胞体外成熟24 h后进行体外受精,于体外受精24 h和3.5 d分别统计胚胎卵裂率和囊胚率,并用Fluorescein-dUTP和Hoechst 33342染色分别检测囊胚总细胞数及囊胚内凋亡细胞比率。【结果】与0 μmol/L Lim组相比,20 μmol/L Lim组小鼠卵母细胞PBI排出率显著升高(P＜0.05),后续试验均用20 μmol/L Lim进行处理。与对照组组相比,20 μmol/L Lim组小鼠卵母细胞内ROS水平显著降低(P＜0.05),GSH、MMP水平均显著增加(P＜0.05),抗氧化相关基因(GPx3、CAT和Prdx3)、抗凋亡相关基因(Bcl-2、Bcl-xl)表达水平均显著上调(P＜0.05),促凋亡相关基因(Caspase-3)表达水平显著下调(P＜0.05);体外受精胚胎的卵裂率、囊胚率、囊胚总细胞数均显著增加(P＜0.05),囊胚内细胞凋亡比率显著下降(P＜0.05)。【结论】在体外成熟培养液中添加20 μmol/L Lim可以通过抑制氧化应激和细胞凋亡、增加MMP水平提高小鼠卵母细胞质量,从而提高体外受精胚胎的发育潜力。     

Seed Maturation Indicators in Pyracantha crenulata Roxb. in Kumaun Central Himalaya

Fruits of Pyracantha crenulata were collected from two locations varying by approximately 550 m in elevation from south aspect for assessing seed maturation indicators. The mean seed size (length×diameter) across the collection dates varied between 1.61 ± 0.7 and 4.93 ± 0.06 mm² across both the locations. The seed moisture content negatively correlated with germination. The change in fruit colour from dark green to light orange, the range of fruit moisture content (30.43% ± 0.06 to 36.10% ± 0.25) and the seed moisture content between 68.8% ± 0.68 and 71.6 ± 0.62 coincided with maximum germination and appear to be major indicators of seed maturation in Pyracantha crenulata.     

杨树材性成熟龄模型的建立及树体内幼龄材的分布

以小叶杨和北京杨的材性测定值(导管分子长度或木纤维长度或导管腔径)作为因变量,以年轮数作为自变量,建立材性成熟非线性模型,以此为依据讨论成熟龄问题,并对幼龄材在树体内的分布进行分析。导管分子长度、木纤维长度和导管腔径的成熟龄模型为应用分段回归分析方法拟合的二次方程和定数函数结合的非线性方程,方程的决定系数在0 85 7～0 991之间,并在0 1 %水平上达到显著。以导管分子长度作为材性指标,应用这个非线性模型分析的结果表明:材性成熟龄及幼龄材半径因树种、立地的灌溉条件不同存在差异。无灌溉北京杨6～1 0年达到成熟,幼龄材半径为5 2mm左右;无灌溉小叶杨2 4～2 9年达到成熟,幼龄材的半径为90mm左右;灌溉小叶杨1 3～1 5年左右达到成熟,幼龄材的半径为85mm左右。     

广东省马尾松经济成熟龄的初探

为探讨在市场经济条件下，使森林利用达到最大经济效益，搜集了广东省东部、西部、北部马尾松用材林的有关资料和数据，采用土地纯收益法、内部收益率模型、净现值一般模型3种方法，计算马尾松用材林的经济成熟年龄为17～20年，     

Evidence of LAT1 expression in canine caput epididymis

L-type amino acid transporter 1 (LAT1), the first isotype of amino acid transport system L, transports aromatic and branched amino acids pivotal for fundamental cellular activities such cellular growth and proliferation. LAT1 expression was high only in the brain in contrast to its limited distribution and low level of expression in normal tissues. We found potent LAT1 expression in canine caput epididymis by quantitative RT-PCR and Western blotting analysis. Immnuno-histochemical examination revealed observable LAT1 in microvillous epithelial cells.     

The effects analysis of two neonicotinoid insecticides on in vitro maturation of porcine oocytes using hanging drop monoculture method

Acetamiprid (ACE) and imidacroprid (IMI) are known neonicotinoid insecticides with strong affinities for the insect-selective nicotinic acetylcholine receptor. These provide insect control by hyperstimulating insect nerves and are used for agricultural pest management. However, it has also been reported that ACE and IMI affect mammalian reproductive function. We determined the effects of ACE and IMI on the in vitro maturation of porcine oocytes. Significant decreases in nuclear maturation rates were observed in the ACE or IMI-exposed groups. Also, in matured oocytes from the ACE or IMI-exposed groups, irregular chromosomes were observed. Our results suggest that ACE and IMI exposure was detrimental to porcine oocytes and the extent of the effects depends on the concentration of exposure.     

Effect of ovarian hormones on maturation of dendritic cells from peripheral blood monocytes in dogs

Previously, we reported that ovarian hormones affect the immune response against E. coli isolated from the dogs affected with pyometra. In order to investigate mechanisms underlying the immune modulation, we examined the effects of ovarian hormones on the generation of dendritic cells (DCs), the most potent antigen presenting cell. DCs were differentiated from peripheral blood monocytes (PBMOs) using a cytokine cocktail. Both estrogen receptor and progesterone receptors were expressed by the PBMOs and immature DCs. When various ovarian hormones were added to the culture for the DC differentiation, progesterone significantly decreased the expression of DC maturation markers, such as CD1a, CD80 and CD86, on mature DCs. Conversely, the addition of estrogen to the cultures increased the expression of CD86, but not other maturation makers. Furthermore, DCs differentiated in the presence of progesterone did not stimulate allogeneic mononuclear cells in PB. Taken together, these results indicate that progesterone diminishes the maturation of DCs, leading to decreased immune responses against invading pathogens.     

山羊卵母细胞体外成熟体系研究进展

卵母细胞体外成熟(IVM)是山羊胚胎体外生产的关键步骤,其对山羊体外生产胚胎的数量和质量均具有非常重要的意义。此外,IVM还可以满足胚胎工程技术如体细胞核移植、转基因动物生产对卵母细胞的大量需求。然而,由于山羊卵母细胞体外成熟研究起步较晚,与牛、猪等家畜相比仍然存在不小的差距,存在诸如体外成熟率低、胚胎质量不佳、培养体系可重复性低等问题。因此,分析山羊卵母细胞体外成熟的主要影响因素,提高山羊卵母细胞体外成熟率,建立山羊卵母细胞体外成熟稳定培养体系,就成为了近年来山羊胚胎体外生产的研究重点。论文综合国内外学者近年的相关研究,对可能影响山羊卵母细胞体外成熟效率的各种因素进行了综述分析,同时对山羊卵母细胞体外成熟现存问题进行了分析,以期为建立山羊卵母细胞体外成熟体系提供理论支持。