哺乳动物的克隆技术——哺乳动物克隆的原理、方法、影响因素及存在的问题

哺乳动物细胞克隆是20世纪末生命科学领域最引人注目的高新技术,该技术对于优良种畜的复制、减少试验用动物数目、动物遗传多样性保存及濒危动物挽救、转基因动物培育等方面具有重要意义。近年来克隆技术发展迅速,多种哺乳动物相继克隆成功,但也存在克隆效率太低、克隆动物表型正常而实质异常的问题。作者阐述了动物克隆的基本原理、操作方法及其相关影响因素,提出了解决相关问题的关键。     

牛卵母细胞体外成熟培养研究进展

作为胚胎生物工程技术研究的基础之一的牛卵母细胞体外成熟培养技术自上世纪30年代起至今,许多科学研究人员在牛卵母细胞体外生长、发育领域做了大量工作,对牛卵母细胞培养条件进行了广泛而深入地研究,并取得了较大的进展,目前牛卵母细胞体外成熟培养技术体系已建立,但在卵母细胞成熟机理、成熟调控方面尚存在许多尚未阐明的问题和一些亟待解决的问题。本文从卵母细胞的来源、卵母细胞体外培养条件、培养液的完善及卵母细胞成熟判定方法等方面详尽介绍了当前牛卵母细胞体外培养技术的研究进展。     

猪卵母细胞去核方法的改进

对猪体细胞克隆技术中关键步骤之一的去核方法作了较深入的研究。结果表明，由本实验室改进的Willadsen去核法——二步挤压去核法，无论在去核操作成功率（73．9％）上还是在去核效率（81．2％）上都明显好于McGrath-Solter去核法（42．5％、67．4％，P〈0．05）；同时，本试验还发现，卵母细胞成熟培养36h后去核组去核效率（89．1％）显著地高于成熟培养44h后去核组（55．8％，P〈0．05），而核移植重构胚的发育率2个组间无显著差异。     

牛卵泡卵母细胞的体外成熟和冷冻保存

在简化牛卵母细胞体外成熟的基础上,观察了保护剂、平衡温度、预平衡方法、解冻方法以及冷冻方法对牛卵泡卵母细胞冷冻的影响。结果表明:在体外成熟培养液中添加26.2 mmol/L的NaHCO3和对屠宰场卵巢进行选择更能促进牛卵母细胞的体外成熟;无论是程序冷冻还是玻璃化冷冻,乙二醇(EG)与甘油(GLY)相比更能促进牛卵泡卵母细胞的冷冻效果;在程序冷冻中,冷冻液中添加0.1 mol/L蔗糖比添加0.3mol/L的蔗糖更能促进牛卵泡卵母细胞的冷冻;在玻璃化冷冻中,37℃和25℃的平衡温度比4℃更适合牛卵泡卵母细胞的冷冻;在10%、5%、1%的预平衡浓度之间,5%的预平衡浓度即可达到预平衡的效果;在解冻时,多步脱除保护剂更能保护冷冻的卵母细胞;比较了几种最小样本量(minimum size sample,MSS)玻璃化冷冻方法,解冻成熟培养后的成熟率,拉细毛细玻璃管冷冻法为(41.67±3.19)%,极显著高于未拉细毛细玻璃管冷冻法(glassmicropipette,GMP)的(30.19±1.93)%和固体表面冷冻法(solid surface vitrification,SSV)的(28.33±2.89)%(P<0.01)。     

附睾功能及其对精子成熟的影响

哺乳动物的附睾为精子的成熟提供了特殊的微环境，是精子成熟、保护、运输和贮存的部位，在生殖过程中起着重要作用。附睾上皮细胞的合成、分泌、转运等功能使精子发生了一系列结构、生化和功能的改变．从而使精子获得受精和运动能力。作者对附睾的形态结构、功能和对精子成熟影响研究现状等作简要综述。     

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)。     

Prevention of isinglass on the chronic atrophic gastritis in rats and its mechanism

AIM: To evaluate the effect of isinglass on chronic atrophic gastritis(CAG) in rats and its mechanism. METHODS: An animal model of CAG in accordance with the previous experience of combined administration of 60% ethanol, 20 mmol/L sodium deoxycholate and 0.1% ammonia water was established in SD rats. Isinglass was used as preventive therapy while we were establishing CAG rat model. Finally all the rats were executed and pathologic changes of the gastric mucosa were studied by gross appearance and microscopy and serum epidermal growth factor (EFG) and growth hormone(GH) contents were tested. RESULTS: In each isinglass prevention group, inflammation grade of gastric antrum was less than that in model group (P<0.01) while the mean ratio of the thickness of gastric mucosal gland and muscularis mucosa (L1/L2), the number of gastric glands in 1 mm lengths of mucosal layer in longitudinal sections were much better than those in model group (P<0.01).They were very close to normal control group (P>0.05). The expression of proliferating cell nuclear antigen (PCNA) in gastric mucosa and serum EFG level were higher than those in model group (P<0.01, P<0.05), but serum GH content showed no different between isinglass prevention group and model group. CONCLUSION: Isinglass preventes the gastric mucosal atrophy in the CAG model. Its mechanism may be related to the effects of decreasing the gastric mucosal damage， promoting the cell proliferation and increasing of internal EFG secretion.     

家蚕核型多角体病毒p35基因的核苷酸序列分析

对家蚕核型多角体病毒苏州株 (BmNPVsu)p35基因的序列分析表明 :BmNPVsup35编码序列为 897nt,编码 2 98aa。同源性分析表明 :BmNPVsup35与BmNPVT3、AcNPV、SlNPV在核苷酸水平上同源性分别为 99.5%、95.1 %、89.3% ,在氨基酸水平上的同源性分别为 98.7%、89.4 %、76.4 % ,显示了杆状病毒p35基因在进化上的保守性。BmNPVT3中位的N14 6、S2 0 2 、E2 0 4 、K2 4 4 ,在BmNPVsu中分别被G、N、Q、N取代 ,BmNPVT3中S2 2 2 ,在BmNPVsuP35中发生了缺失。推测BmNPVsuP35蛋白的功能及抑制细胞凋亡的能力与BmNPVT3P35蛋白的相似     

Amelioration of Aluminum Toxicity by Pretreatment with Phosphate in Aluminum‐Tolerant Rice Cultivar

Abstract

The phytotoxicity of aluminum (Al) in relation to preculture with phosphates was examined in the rice cultivar Arkansas fortuna. In plants precultured with phosphates, Al did not inhibit shoot growth, while Al retarded shoot growth in plants precultured without phosphates. In contrast, Al inhibited root elongation, irrespective of the presence of phosphates in the preculture solution. A large proportion of the Al in roots was in unknown, insoluble forms. In phosphate‐precultured plants, Al deposition was slightly increased, presumably due to the formation of aluminum phosphates in the roots, and phosphorus levels in shoots were markedly increased. Binding with phosphates may ameliorate the toxicity of Al when it enters the shoots and account for the uninhibited shoot growth in the presence of Al in plants precultured with phosphates.