山羊卵母细胞的显微受精

探讨了显微操作条件的改善对山羊卵母细胞胞质内显微受精(ICSI)的影响。结果表明,将精子操作液中聚乙烯吡咯烷酮(PVP)浓度从10%(10g/L)降低到8%和5%后,ICSI胚的卵裂率差异不显著,但正常卵裂率、桑葚胚率和囊胚率随PVP浓度的下降而上升;PVP浓度为5%和10%时,正常卵裂率分别为69.6%和58.5%(P<0.05),桑葚胚率分别为45.6%和35.2%(P<0.05),囊胚率分别为26.9%和16.9%(P<0.05),表明含5%PVP的精子操作液更有利于ICSI胚的发育。显微注射时将卵母细胞第一极体置于相当于时钟6点的位置与12点位置相比,ICSI胚的分裂率没有差异,而正常卵裂率分别为69.9%和65.4%(P>0.05),桑椹胚率分别为45.5%和42.6%(P>0.05),囊胚率分别为26.7%和20.4%(P>0.05),表明注射时极体置于6点的位置有利于ICSI胚的体外发育。     

Collagen synthesis in Xenopus oocytes after injection of nuclear RNA of frog embryos

A messenger RNA fraction from polysomes of frog larvae or RNA preparations from isolated nuclei of developing frog embryos were injected into growing Xenopus laevis oocytes that were incubated with labeled proline. Column chromatography of protein hydrolyzates revealed labeled hydroxyproline after injection of the messenger RNA fraction and neurula nuclear RNA, indicating that the injected material had promoted collagen synthesis.     

Introduction of human DNA into mouse eggs by injection of dissected chromosome fragments

A procedure has been developed for introducing exogenous DNA into mouse eggs by injection of chromosome fragments. Chromosome fragments were dissected from human metaphase spreads and microinjected into the pronuclei of fertilized mouse eggs. Many of the injected eggs subsequently exhibited normal pre- and postimplantation development. Embryos obtained from eggs injected with centromeric fragments retained human centromeric DNA as demonstrated by in situ hybridization analysis. From eggs injected with noncentromeric fragments, a mouse was obtained whose tail tissue exhibited the presence of human DNA. This procedure should facilitate incorporation of very large (more than 10 megabases) DNA fragments into cells and embryos without the need for cloned sequences.     

Chromatin-independent nuclear envelope assembly induced by Ran GTPase in Xenopus egg extracts

The nuclear envelope (NE) forms a controlled boundary between the cytoplasm and the nucleus of eukaryotic cells. To facilitate investigation of mechanisms controlling NE assembly, we developed a cell-free system made from Xenopus laevis eggs to study the process in the absence of chromatin. NEs incorporating nuclear pores were assembled around beads coated with the guanosine triphosphatase Ran, forming pseudo-nuclei that actively imported nuclear proteins. NE assembly required the cycling of guanine nucleotides on Ran and was promoted by RCC1, a nucleotide exchange factor recruited to beads by Ran-guanosine diphosphate (Ran-GDP). Thus, concentration of Ran-GDP followed by generation of Ran-GTP is sufficient to induce NE assembly.     

Morphine tolerance and dependence induced by intraventricular injection

Injection of small quantities of morphine into the cerebral ventricular system of awake, relatively unrestrained, monkeys depressed or abolished operant food-reinforced lever pressing. After repeated injections progressively higher doses of morphine were needed to depress responding. Also, dependence could be demonstrated in these animals by precipitating specific abstinence signs with an antagonist.     

Sterility in female guinea pigs induced by injection with testis

Adult virgin female guinea pigs were injected with an emulsion of homologous adult testis and Freund's adjuvant before exposure to males. The fertility of this group was only 24 percent while the fertility of the control group was 84 percent. The testis-injected guinea pigs had also a high titer of antibodies against testis.     

Electrical responses of eggs to acrosomal protein similar to those induced by sperm

The earliest known response of eggs to sperm in many species is a change in egg membrane potential. However, for no species is it known what components of the sperm cause the opening of the egg plasma membrane channels. Protein isolated from sperm acrosomal granules of the marine worm Urechis caused electrical responses in oocytes with the same form, amplitude, and ion dependence as the fertilization potentials induced by living sperm. Sperm initiated fertilization potentials in oocytes when sperm-oocyte fusion, but not binding, was inhibited by clamping oocyte membrane potentials to positive values. Acrosomal protein also initiated electrical responses in clamped oocytes. These results support the hypothesis that it is the sperm acrosomal protein that opens ion channels in the oocyte membrane.     

PrPc重组蛋白脑内接种金黄地鼠对mRNA表达的影响

为明确将牛PrPc重组蛋白接种金黄地鼠脑内是否引起异常临床表现、脑组织病理学变化及对其mRNA表达产生影响,为进一步研究PrPc蛋白与异构体PrPsc 的结构转换机制提供基础数据,将纯化的牛PrPc重组蛋白磷酸盐缓冲液制剂进行地鼠颅内接种,约3 μL/只,对照接种磷酸盐缓冲液（PBS）;102 d后取出脑组织：一部分福尔马林固定后进行常规H.E.染色观察, 另一部分提取脑组织总RNA,进行实时荧光定量RT-PCR检测.结果表明：处理未见临床异常表现;大脑、小脑、脑干组织病理学检测未见海绵状空泡变性和淀粉样斑;大脑PrPc mRNA表达水平无显著性差异.上述结果表明,用PrPc重组蛋白接种,在检测时间102 d内未引起金黄地鼠行为和脑组织的异常改变.     

侧脑室注射瘦素对大鼠垂体生长激素mRNA表达的影响

为了探讨Leptin(瘦素)对动物生长激素(GH)分泌的影响,以大鼠为试验动物,通过侧脑室注射1 mg Leptin,并采用逆转录多聚酶链反应(RT-PCR)法测定了大鼠垂体GH mRNA表达水平。结果表明,大鼠侧脑室注射Leptin,能显著增加垂体GH mRNA的表达。这一结果证明了Leptin可通过下丘脑调控动物垂体GH的合成与分泌。     

Restoration of the plasticity of binocular maps by NMDA after the critical period in Xenopus

Visual input during a critical period of development plays a major role in the establishment of orderly connections in the developing visual system. In Xenopus laevis, the matching of visual maps from the two eyes to the optic tectum depends on binocular visual input during the critical period, which extends from late tadpole to early juvenile stages. Alterations in eye position, which produce a mismatch of the tectal maps, normally evoke a compensatory adjustment in the map of the ipsilateral eye only during the critical period. However, continuous application of the glutamate receptor agonist N-methyl-D-aspartate (NMDA) after the normal end of the critical period restores this ability to realign the visual map.     

SelW mRNA下调对肌细胞状态影响的FGM评估

运用RNA干扰技术,在转录后阶段实现肌细胞中SelW mRNA的定量下调,并利用流式细胞术客观地区分、计数不同状态的细胞,考察C2C12细胞中SelW mRNA的定量下调对细胞状态的影响。结果显示:当siR-NA剂量为2.0,1.5,1.2μg/g时,细胞脱落、死亡;当siRNA剂量为1.0,0.5,0.25μg/g时,凋亡率分别为32.5%,12.4%,6.58%。在干预评估试验中,阴性对照组与空白对照组差异显著(P<0.01)。细胞状态随SelW mRNA的下调存在着阶段性变化,凋亡率与mRNA的降低量之间的关系为非线性正相关,证明SelW对肌细胞的健康是必须的。显著的凋亡率表明SelW对肌细胞的功能重要性的机制是十分复杂的,尚需进一步研究。     

Nuclear factors in B lymphoma enhance splicing of mouse membrane-bound mu mRNA in Xenopus oocytes

Regulation of the synthesis of membrane-bound and secreted immunoglobulin mu heavy chains at the level of RNA processing is an important element for B cell development. The precursor mu RNA is either polyadenylated at the upstream poly(A) site (for the secreted form) or spliced (for the membrane-bound form) in a mutually exclusive manner. When the mouse mu gene linked to the SV40/HSV-TK hybrid promoter was microinjected into Xenopus oocytes, the mu messenger RNA (mRNA) was altered by coinjection of nuclei of mouse surface IgM-bearing B-lymphoma cells to include the synthesis of the membrane-bound form. An increase in the membrane-bound form was not observed when nuclei of IgM-secreting hybridoma cells or fibroblast cells were coinjected. Deletion of the upstream poly(A) site did not eliminate the effect of B-lymphoma nuclei suggesting that membrane-specific splicing is stimulated. Further, splicing of other mu gene introns was not affected by coinjection of B-lymphoma nuclei. These results suggest that mature B cells contain one or more transacting nuclear factors that stimulate splicing specific for membrane-bound mu mRNA.     

参附注射液对大鼠心肌缺血再灌注损伤心电图的影响

目的观察参附注射液对大鼠心肌缺血再灌注损伤时ST段和心律失常的影响。方法健康SD大鼠24只随机分为两组,缺血再灌注组（IR组）和参附注射液预处理组（SF组）,每组12只。采用夹闭左冠状动脉30 min,再灌注90min,复制心肌缺血再灌注模型。夹闭前SF组静脉注射参附注射液5 mL/100g进行预处理,观察各组大鼠在整个缺血再灌注期间心电图ST段和心律失常发生情况。结果SF组ST段变化均低于IR组各时间对应值,SF组心肌缺血再灌注后的室性心动过速及心室颤动的发生率均明显低于IR组,差异均有统计学意义（P＜0.01或0.05）。结论参附注射液能降低心肌缺血再灌注损伤程度和室性心律失常发生率。     

Recovery of memory after amnesia induced by electroconvulsive shock

Electroconvulsive shock given to rats immediately after one-trial avoidance learning produced a significant amnesic effect 24 hours later; this amnesia had largely disappeared in further retention tests 48 and 72 hours after treatment. This result puts in question a basic assumption implicit in most memory consolidation studies that such amnesic effects will be permanent.     

利用mRNA差异显示技术克隆恶疫霉侵染诱导表达的草莓基因

为了解草莓与恶疫霉互作的分子机制,以接种后3、5和7 d的感病草莓品种‘FDP821’的冠部为材料,利用mRNA差异显示技术研究‘FDP821’与恶疫霉亲和互作前后基因表达的差异,获得78条差异表达的cDNA片段,通过分析从中分离出恶疫霉侵染诱导表达的10个草莓基因cDNA片段。BLASTX在线分析表明,这些草莓基因的功能涉及呼吸作用、衰老和核苷运输与代谢等。为阐明草莓与恶疫霉互作的分子机制提供了重要的线索。     

福建菜后稻氮磷钾施肥指标研究

为建立福建菜后稻氮磷钾施肥指标,在福建省蔬菜主产区进行63个菜后稻氮磷钾肥效田间试验。结果表明,菜后稻的空白区产量与平衡施肥产量之间满足线性关系,菜田对稻谷产量的平均贡献率为79.1%,施用氮磷钾平均增产16.5%、6.7%和9.0%。"极高"土壤肥力等级的碱解氮、Olsen-P和速效钾含量分别为>230mg.kg-1、>54 mg.kg-1和>140 mg.kg-1,"中低"土壤肥力等级则分别为<200 mg.kg-1、<19mg.kg-1和<74mg.kg-1,"高"土壤肥力等级的相应指标范围则介于二者之间。"极高"土壤肥力等级的超高产水稻经济施肥量为N 150kg.hm-2、P2O545kg.hm-2和K2O 92kg.hm-2,"高"土壤肥力等级的普通水稻品种经济施肥量为N 62kg.hm-2、P2O520kg.hm-2和K2O 57kg.hm-2,"中低"土壤肥力等级则为N120kg.hm-2、P2O537kg.hm-2和K2O 40kg.hm-2。土测值与菜后稻的推荐施肥量之间满足指数模型,建立了不同土壤肥力等级的土测值与推荐施肥量的回归方程式,达到了因土施肥的目的。     

平衡施肥在玉米生产中的增产效果

在玉米种植中，以往我们只注重改良品种和改变种植方式来提高产量。而忽视通过改变施肥技术来达到增产目的。随着单位面积及复种指数的升高，土地利用率和产量的加大，土壤中大量养分被作物带走，而这些被带走的养分又没有及时的补充，使土壤肥力逐步下降，造成土壤养分失调，对下季作物的生长极为不利；加上现在农     

高浓度氧处理法阻断蚕卵滞育

【目的】比较高浓度氧处理法(高氧法)与传统HCl处理法(HCl法)阻断蚕卵滞育效果的差异,探讨高氧法阻断滞育在家蚕Bombyx mori转基因技术体系上的应用。【方法】采用高氧法和HCl法在产后20 h处理二化性蚕品种‘大造’,比较孵化率、孵化时间,调查高氧法的最佳处理条件;将高氧法应用于一化性蚕品种‘土耳其’和转基因二化性蚕品种‘大造’,调查其对一化性蚕品种蚕卵阻断滞育效果及转基因二化性蚕品种显微注射后蚕卵阻断滞育效果。【结果】高氧法对二化性蚕卵在孵化率、孵化时间上都与HCl法有相近的阻断滞育的效果,其最佳条件为产卵后20 h用体积分数为70%的O2处理40 h;该方法也能成功阻断一化性蚕品种,孵化率达(71±20)%;高氧法处理的显微注射转基因家蚕卵孵化率达到了(49±9)%,而对照组的孵化率为0。【结论】高氧法为今后生产上替代HCl法,采用安全环保的蚕卵阻断滞育技术,解决转基因蚕卵阻断滞育和提高转基因家蚕育种进度的关键问题提供了可行的新方法。