异源精子诱导栉孔扇贝雌核发育早期胚胎发育及其倍性分析

采用紫外线遗传灭活的长牡蛎（Crassostrea gigas）精子作激活源,经6-DMAP加倍诱导栉孔扇贝（Chlamys farreri）第二极体抑制型雌核发育二倍体;运用荧光显微技术,对雌核发育二倍体卵子早期胚胎发育过程中的核相变化进行观察。结果显示,紫外线处理过的精子入卵后发生一次轻微膨胀,形成雄性原核,但不形成染色体,而是浓缩为致密的染色质小体（DCB）,DCB或滞留于两卵裂球的分裂沟上或进入其一的细胞质中,不与雌原核融合;雌核发育胚胎的发育速度明显滞缓,经6-DMAP处理后胚胎发育速度加快,发育同步化;在雌核发育二倍体诱导过程中,还观察到杂交体、异源三倍体、雌核发育单倍体、雌核发育四倍体。结果为异源精子诱导栉孔扇贝雌核发育提供了细胞学证据。     

X195柴油机掺水燃烧的试验研究

 结合195柴油机的结构特点,在不改变原机任何结构的前提下,增设一套供水系统,发动机工作时,喷水器适时向气缸内喷射一定量的水,喷入气缸的水微粒在高温高压的条件下产生“微爆”效应,使柴油颗粒进一步雾化和高度分散,与空气混合更加均匀,促使燃料完全燃烧,以达到节油,降污的目的。试验结果表明,增设的供水系统工作性能的可靠,掺水燃烧时比油耗及排烟度等明显下降。     

不同精子处理对应用ICSI—Tr技术生产转基因水牛胚胎效率的影响

本文主要探讨了不同精子处理对应用显微授精介导（intracytoplasmic sperm injection-mediatedtrans-genesis,ICSI-Tr）生产转基因水牛胚胎效率的影响。本试验以p18T—BCN5．2-IFN-1．1pA—EGFP为载体,比较了精子的不同处理方式（NaOH和冻融）、NaOH处理精子不同时间（5min,10min,20min,30min和60minl以及不同外源DNA浓度（5ng／μL,10ng／μL,25ng／μL和50ng／μL）对ICSI-Tr转基因效率的影响。结果显示：NaOH处理组的囊胚EGFP表达率（46．1％）,与冻融精子处理组（47．1％1差异不显著,但发育率显著高于冻融处理精子组（28．3％VS16．7％,P〈0．05）。处理60min组和30min组的分裂率分别为78．9％和77．5％,显著高于20min、10min和5min组的64．0％、60．0％和64．0％（P〈0．05）,其中30min处理组的囊胚EGFP表达率高达44．4％,显著高于其它处理组（P〈0．05）。25ng／μL组和50ng／μL组的早期胚胎EGFP表达效率差异不显著（41．3％VS42．5％）,但显著高于5ng／肚组和10ng／μL组（22．5％和35．5％）,25ng／μL组的囊胚EGFP表达效率显著高于其它组（P〈0．05）。本研究优化了应用ICSI-Tr生产转基因水牛胚胎技术体系,为获得ICSI-Tr转基因水牛奠定了良好的工作基础。     

Transmission electron microscopy for characterization of acrosomal damage after Percoll gradient centrifugation of cryopreserved bovine spermatozoa

The objective of this study was to characterize acrosomal ultrastructure following discontinuous Percoll gradient centrifugation of cryopreserved bovine sperm. Semen was collected from six bulls of different breeds and three ejaculates per bull were evaluated. Frozen semen samples were thawed and the acrosomal region of sperm cells was evaluated by transmission electron microscopy (TEM) before (n = 18) and after (n = 18) Percoll centrifugation. The evaluation of 20 sperm heads from each of the 36 samples analyzed ensured that a large number of cells were investigated. The data were subjected to analysis of variance at a level of significance of 5%. Percoll centrifugation reduced the percentage of sperm exhibiting normal acrosomes (from 61.77 to 30.24%), reduced the percentage of sperm presenting atypical acrosome reactions (from 28.38 to 4.84%) and increased the percentage of sperm exhibiting damage in the acrosome (from 6.14 to 64.26%). The percentage of sperm with typical acrosome reactions was not significantly different before (3.70%) and after (0.67%) centrifugation. TEM distinguished four different types of acrosomal status and enabled ultrastructural characterization of acrosomal injuries. The percentage of sperm exhibiting normal acrosomes decreased and damage in the acrosome was the most frequent acrosomal injury with the Percoll gradient centrifugation protocol utilized.     

The addition of calcium ion chelator,EGTA to thawing solution improves fertilizing ability in frozen–thawed boar sperm

In our previous study, seminal plasma effectively suppressed the induction of sperm to capacitation‐like status and acrosome loss during the thawing process. However, because boar seminal plasma is contaminated with various kinds of bacteria and/or viruses, it is necessary to develop a thawing solution without animal‐derived materials. In this study, we focused on the increase of intracellular Ca²⁺ ([Ca²⁺]_i) in sperm after thawing and the negative effects of sperm qualities. After thawing, the fluorescent intensity of [Ca²⁺]_i indicator, Fluo‐3/AM, and the level of phosphorylated tyrosine residue of protein were increased in the sperm. Next, we investigated whether the addition of Ca²⁺ chelators (ethylenediaminetetraacetic acid (EDTA) and ethyleneglycoltetraacetic acid (EGTA)) improved post‐thawed sperm motility. When the frozen–thawed sperm were treated with 6 mmol/L EDTA + 6 mmol/L EGTA, sperm motility was significantly increased as compared with control (6 mmol/L EDTA alone) at all incubation periods (P < 0.05). The combinational treatment significantly suppressed the elevation of [Ca²⁺]_i and the tyrosine phosphorylation, which improved the acrosomal status and fertilizing ability in vitro. Furthermore, when the thawing method was applied for artificial insemination, the fertilization rate was significantly higher than control (P < 0.05, 33% vs. 82%). Thus, we conclude that the addition of EDTA + EGTA to thawing solution is a beneficial tool for artificial insemination using frozen–thawed boar sperm.     

禽肠炎沙门菌外膜蛋白OMPX基因的克隆及其在乳酸乳球菌中的表达

以禽肠炎沙门菌基因组DNA为模板,采用PCR技术扩增得到外膜蛋白OMPX基因片段,并将其克隆到乳酸乳球菌表达载体pMG36e中,构建重组质粒pMG36e-OMPX。将重组质粒电转入乳酸乳球菌MG1614,得到重组基因工程乳酸乳球菌,在GM17培养基中培养12h后,经SDS-PAGE分析显示表达的蛋白约为16 000,与预期相符,经Western-blot检测表明,表达的蛋白具有良好的反应特异性。     

3-甲基-4-硝基酚对雄性小鼠生殖毒性的研究

目的探讨3-甲基-4-硝基酚(PNMC)对雄性小鼠的生殖毒性作用。方法 20只小鼠随机分成阴性对照组和PNMC组(分0.9、9和90mg/kg·bw组),经口灌胃染毒30天,观察睾丸和精子的形态变化。结果染毒组小鼠各剂量睾丸生精细胞发生坏死,曲细精管腔内出现细胞团,精子细胞分化异常,形成均质红染颗粒,睾丸曲细精管生精上皮/直径比值在90mg/kg组明显高于对照组;染毒组小鼠精子畸形率明显高于对照组(P<0.05),并且随着染毒浓度的增加,畸形率有增加的趋势。结论 3-甲基-4-硝基酚不仅可以引起生精细胞坏死和抑制精子形成,还可以诱导精子畸变,从而对生殖系统造成损伤。     

MEASUREMENT OF BODY COMPOSITION IN CATS USING COMPUTED TOMOGRAPHY AND DUAL ENERGY X‐RAY ABSORPTIOMETRY

Dual energy X‐ray absorptiometry (DEXA) is a reference method for assessing body composition but is seldom `accessible in veterinary settings. Computed tomography (CT) can provide similar body composition estimates and we propose that it can be used in body composition studies in animals. We compared CT and DEXA data from 73 healthy adult neutered domestic cats. Three approaches for measuring adipose tissue percentage from full‐body CT scans were explored. By examining the frequency distribution of voxels by Hounsfield unit (HU) value, it is possible to calculate a fat index (Fat%) that is in close agreement with the fat percentages obtained from DEXA scans. Fat% values obtained by the best of the methods had a mean difference of 0.96% (95% confidence interval 0.33–1.59%) from the DEXA results. Fat% obtained by the other two methods were characterized by good correlation but poor agreement and in one of the methods, the difference between the values from the two modalities was proportional to their mean. By using CT, it is possible to obtain body composition estimates that are in close agreement with those available using DEXA. While the significance of individual Fat% measurements obtained from CT can be difficult to interpret and to compare between centers, CT can contribute to research studies concerned either with nutrition or with obesity‐related disorders.     

X染色体失活、失活逃逸及相关疾病的研究进展

剂量补偿效应是表观遗传的机制之一,它是指使X连锁基因的表达水平在两性间达到平衡的过程。不同的物种所实现剂量补偿的机制不同,人同其他哺乳动物的剂量补偿机制是雌性个体随即失活一条X染色体。但最近的研究发现,在人和小鼠的失活X染色体上有些基因仍能表达,逃避了失活。目前,许多人类疾病尤其是具有女性发病优势病症的发生与治疗可能与这些逃逸基因密切相关。针对以上内容的最新进展作了相关综述。