产中性纤维素酶特异腐质霉H31-3复合诱变研究

中性纤维素酶在纺织、食品、饲料和制药行业均具有广泛的应用。采用离子束注入技术对中性纤维素酶产生菌特异腐质霉（Humicola insolens）H31-3进行诱变,经发酵筛选获得较高酶活力且传代稳定的正突变菌株H14,制备其原生质体后进行紫外诱变。筛选后得到正突变菌株H14．2,最终CMC酶、滤纸酶活力分别达82．56IU／mL和5．77IU／mL,较原始菌株提高了78．57％和106．81％。     

Desmosomes in uterine epithelial cells decrease at the time of implantation: an ultrastructural and morphometric study

Displacement of uterine epithelial cells is an important aspect of implantation in the rat and other species, allowing invasion of the blastocyst into the endometrial stroma. Desmosomes, which are part of the lateral junctional complex, function in cell-to-cell adhesion, and are therefore likely to be involved in displacement of uterine epithelial cells at the time of implantation. This study used transmission electron microscopy to study rat uterine epithelial cells during the peri-implantation period to investigate the change in the number of structural desmosomes along the lateral plasma membrane of uterine epithelial cells. We found a significant decrease in the number of desmosomes along the entire lateral plasma membrane as pregnancy progressed. Furthermore, there were also significant decreases in the number of desmosomes on the apical portion of the lateral plasma membrane between all days of pregnancy examined. In addition, on day 6 of pregnancy, the time of attachment, desmosomes were larger and seen as "giant desmosomes." For the first time, this study has shown that there is a significant reduction in cell height and actual number of ultrastructurally observable desmosomes at the time of implantation in the rat. It is proposed that this reduction in desmosome number leads to a decrease in lateral adhesion between uterine epithelial cells at the time of implantation, and hence is involved in the loss of uterine epithelial cells to facilitate blastocyst invasion.     

骨髓间充质干细胞源神经细胞移植治疗帕金森病大鼠模型

目的探讨骨髓间充质干细胞（mesenchymal stemcells,MSCs）源神经细胞脑内移植对帕金森病（Parkinson s disease,PD）大鼠的治疗作用。方法贴壁培养法分离、培养大鼠骨髓MSCs,脑匀浆上清诱导第3代MSCs向神经细胞分化,采用免疫细胞化学法鉴定诱导分化后细胞的性质,激光共聚焦显微镜检测诱导前后细胞Ca2＋浓度变化,6只PD大鼠行纹状体内MSCs源神经细胞移植作为细胞移植组,6只PD大鼠作为对照组。细胞移植术后4周检测PD大鼠的行为变化,观察移植细胞在脑内的分布情况。结果倒置显微镜下可见MSCs呈纺锤形和多角形,有1～2个核仁,MSCs经脑匀浆上清诱导后其胞体折光性增强,发出数个细长突起,互相交织成网,有的似轴突。诱导后细胞表达神经元特异性标志物神经元特异性烯醇化酶（NSE）和神经丝蛋白（NF）,胞质Ca2＋荧光强度显著增强,可推测诱导后的细胞为MSCs源神经细胞,将BrdU标记的MSCs源神经细胞移植到PD大鼠纹状体治疗4周后,可见细胞散在分布于注射侧脑组织,有少量细胞可迁移到对侧脑组织,PD大鼠的旋转行为得到显著改善。结论MSCs源神经细胞移植治疗帕金森病大鼠可使其旋转行为得到改善。     

通过体内基因转染改变Meis1在围着床期小鼠子宫中的表达影响胚胎着床

通过宫腔内脂质体转染改变小鼠子宫内Meis1基因的表达水平,研究其对子宫内膜容 受性的影响,从而推测Meis1基因在胚胎着床中的作用.选择8～12周龄昆明小鼠,于妊娠 第2 ｄ,通过向小鼠宫腔内注入Meis1基因表达质粒和siRNA表达质粒及其各自的对照质粒 ,在妊娠第5ｄ, 提取小鼠子宫mRNA 和蛋白质行半定量RT-PCR 和免疫组化分析,观察各组小鼠子宫内膜Meis1和整合素β3的表达变化.在妊娠第9 ｄ,观察Meis1基因上调组及其对 照组、Meis1基因下调及其对照组妊娠率和胚胎着床数的差异.结果显示,Meis1基因下调组胚胎着床率明显低于对照组（P<0.05）,Meis1基因上调组胚胎着床率略高于对照组,但无统计学意义（P>0.05）;Meis1基因上调组其整合素β3的表达高于其对照组,Meis1基因下调组 整合素β3的表达低于其对照组,差异均有显著性（P<0.05）.以上观察结果表明,Meis1基因表达下降可明显减少胚胎着床率,影响整合素β3的表达.Meis1基因表达提高则可促进整合素β3的表达. 因此,Meis1可能作为1种子宫内膜容受分子,在胚胎着床中发挥重要作用.     

Individual blastomeres of 16- and 32-cell mouse embryos are able to develop into foetuses and mice

Cell and developmental studies have clarified how, by the time of implantation, the mouse embryo forms three primary cell lineages: epiblast (EPI), primitive endoderm (PE), and trophectoderm (TE). However, it still remains unknown when cells allocated to these three lineages become determined in their developmental fate. To address this question, we studied the developmental potential of single blastomeres derived from 16- and 32-cell stage embryos and supported by carrier, tetraploid blastomeres. We were able to generate singletons, identical twins, triplets, and quadruplets from individual inner and outer cells of 16-cell embryos and, sporadically, foetuses from single cells of 32-cell embryos. The use of embryos constitutively expressing GFP as the donors of single diploid blastomeres enabled us to identify their cell progeny in the constructed 2n↔4n blastocysts. We showed that the descendants of donor blastomeres were able to locate themselves in all three first cell lineages, i.e., epiblast, primitive endoderm, and trophectoderm. In addition, the application of Cdx2 and Gata4 markers for trophectoderm and primitive endoderm, respectively, showed that the expression of these two genes in the descendants of donor blastomeres was either down- or up-regulated, depending on the cell lineage they happened to occupy. Thus, our results demonstrate that up to the early blastocysts stage, the destiny of at least some blastomeres, although they have begun to express markers of different lineage, is still labile.     

低能氮离子注入诱变选育高产结冷胶菌株的研究

结冷胶是由伊乐假单胞杆菌生成的具有重要商业价值的微生物胞外多糖。本研究为了提高伊乐假单孢菌的产结冷胶水平,采用低能氮离子注入的方法选育高产菌株。经过初筛和复筛得到一株高产结冷胶菌株Pseudomonas elodea A3-5。该菌株传代稳定,生长迅速,在7 L发酵罐内生长状态优于出发菌株,分子量和品质都较高,分批发酵结冷胶产量达到16.5g/L,较出发菌株明显提高了25%。     

N^＋注入对紫薇光合特性和叶绿素含量的影响

采用离子注入诱变育种技术对紫薇种子进行处理,正常播种后测两年生植株叶片的光合特性和叶绿素含量,结果表明：与对照相比,经离子注入处理后,各处理的净光合速率都有不同程度的增加,光合速率饱和时所需要的光合有效辐射均较未注入处理的低。叶绿素a和b的绝对含量呈现双峰型变化趋势,但叶绿素a的增加量受注入剂量的影响较大,叶绿素a/b比值变化不明显,离子注入处理能提高紫薇幼苗的潜在光合能力和耐荫性。     

人胚胎干细胞向滋养层分化的研究进展

哺乳动物胚胎发育产生的第一个细胞系的分离是内细胞团和滋养层的分离,不同哺乳动物之间胚胎干细胞向滋养层细胞分化不同,滋养层细胞对胚胎的植入、促进胚胎在子宫内的生存和生长至关重要.人胚胎干细胞为研究人类胚胎发育及向滋养层分化提供了一个独特的模型.人胚胎干细胞可以在实验室条件下保持无限期稳定的培养,用于最初胚胎和滋养外胚层发生的机制研究.目前人胚胎干细胞分化为滋养层细胞在体外可以通过自发分化、基因敲除、分离EB小体和BMP4诱导等几种途径实现.不同哺乳动物之间胚胎干细胞向滋养层分化机制,主要通过信号通路如BMP4,LIF等以及某些标志基因如OCT4,CDX2,Eomes等的变化调节.人胚胎干细胞向滋养层分化的研究为临床应用提供了一定的基础.     

不同温度条件下小鼠囊胚OPS法玻璃化冷冻保存技术的研究

本实验采用OPS法在不同温度条件下对小鼠囊胚实施冷冻保存,研究用EDFS和EFS溶液冷冻保存囊胚的效率和提供不同温度下筛选玻璃化溶液的依据,为家畜和人类胚胎的冷冻保存建立模型。25℃室温和37℃恒温台条件下OPS一步法冷冻保存小鼠囊胚,EFS40和EDFS40冷冻组扩张囊胚率(92.31%,92.30%)与对照(97.26%)均无显著差异(P>0.05),但EDFS40孵化囊胚率(59.62%)显著低于对照组(83.56%)(P<0.05);二步法冷冻结果显示,采用EDFS30和EFS40均能高效保存小鼠囊胚,解冻后扩张囊胚率(95.69%和95.05%)和孵化率(80.48%和78.95%)与对照无显著差异(P>0.05)。当改为25℃室温不使用恒温台条件下,一步法冷冻的胚胎解冻后,仅EDFS40冷冻组扩张囊胚率和孵化囊胚率(85.96%和75.44%)与对照(96.05%和82.89%)无显著性差异(P>0.05);实施二步法冷冻的胚胎,解冻后EDFS30,EDFS40和EFS40组均获得理想效果,扩张囊胚率(92.03%-95.31%)及孵化囊胚率(67.19%-76.76%)与对照均无显著差异(96.05%和82.89%)(P>0.05)。据体外发育结果,选择最佳冷冻组胚胎移植给假孕4d的受体母鼠,其妊娠率和产仔率(90.90%和37.33%)与新鲜胚对照组(91.67%和42.33%)无显著差异(P>0.05)。结果证实,EDFS30、EDFS40和EFS40三种冷冻液在不同的温度条件和采用不同冷冻程序,均能成功保存小鼠囊胚。