猪霍乱沙门氏菌C78-1株ΔcrpΔasd缺失株平衡致死载体系统的构建及生物学特性研究

为开发减毒猪霍乱沙门氏菌的活疫苗载体,通过自杀性质粒介导的细菌同源重组技术,构建了猪霍乱沙门氏菌C78-1株ΔcrpΔasd双基因缺失株,并对其生物学特性进行探讨。首先构建含有缺失1 488bp asd基因的重组自杀性质粒pREΔasd,然后与已构建完成的ΔcrpC78-1缺失株进行接合转移,采用两步法筛选无抗性的C78-1的ΔcrpΔasd双缺失株。PCR鉴定结果表明,C78-1的ΔcrpΔasd双缺失株构建成功;进一步研究表明,该缺失株的生长需要外源的二氨基庚二酸(DAP),且能稳定遗传缺失的asd基因,与C78-1相比,其血清型未发生变化,但其生长速度明显减慢。ΔcrpΔasd C78-1双缺失株可接受asd+质粒作为宿主平衡致死系统高效稳定地表达外源基因,为开发以C78-1为载体的口服多价疫苗奠定了基础。     

猪传染性胃肠炎病毒S基因重组腺病毒的构建及特性研究

将克隆的猪传染性胃肠炎病毒(TGEV)全长S基因插入pAdTrack-CMV穿梭质粒中,形成的转移质粒pAdTrack-CMV/S线性化后,用pAdEasyTM系统电转化含有腺病毒骨架载体pAdEasy-1的感受态大肠埃希氏菌BJ5183,经同源重组,构建了含有全S基因的重组腺病毒载体,经酶切充分暴露反向末端重复序列后,与脂质体混合转染AD-293细胞,成功获得了AD-S复制缺陷型腺病毒,经检测证实,AD-S稳定性好,安全性高。转录水平检测证实,S基因得到了转录;荧光检测发现,外源蛋白已得到表达。     

鼠伤寒沙门氏菌Χ4550 FlhD基因缺失株的构建

为构建鼠伤寒沙门氏菌Χ4550FlhD基因缺失所致的鞭毛缺失株,采用PCR技术从减毒鼠伤寒沙门氏菌Χ4550基因组DNA中扩增出了鞭毛控制操纵子基因(FlhD)两侧翼基因片段,作为FlhD基因敲除所需的上臂和下臂的同源序列;以pKD4质粒为模板,扩增了卡那霉素(Km)抗性基因,并分别克隆入pMD18-T载体中,获得了重组质粒pMD-FlhD-U、pMD-FlhD-D和pMD-Km。将获得的上臂和下臂基因以及卡那霉素抗性基因通过拼接,构建重组质粒pMD-ΔFlhD/Km。将重组片段ΔFlhD/Km亚克隆入pG-MB151自杀质粒,并转化大肠杆菌χ7213,获得重组菌χ7213(pGMB151-ΔFlhD/Km)。将此细菌作为供体菌,与受体菌鼠伤寒沙门氏菌Χ4550进行固相杂交,经同源重组和抗生素筛选,获得鼠伤寒沙门氏菌Χ4550(ΔFlhD/Km)鞭毛缺失株。通过PCR扩增、动力学鉴定及电镜观察,显示鼠伤寒沙门氏菌Χ4550的FlhD基因已被成功敲除。证实,运用同源重组的方法可成功地敲除鼠伤寒沙门氏菌Χ4550的FlhD基因,并导致其鞭毛缺失,为鼠伤寒沙门氏菌鞭毛的功能研究奠定基础。     

并购重组与文化整合

市场中并购重组的成功率相对较低的重要原因之一,是企业往往只看到市场上有形的重组与并购活动的表层,而对企业所必须面对的深层的异质文化挑战浑然不知,最终致使并购重组后企业的协同效应根本无法实现,甚至优质企业也可能被这种文化的不适所拖垮。     

双顺反子表达质粒在DNA疫苗研究中的应用

简述了DNA疫苗的研究概况,介绍了真核双表达质粒的结构特点及其在基因佐剂和二价DNA疫苗中的应用情况,总结分析了双表达质粒的优点和存在的问题,并对其今后在DNA疫苗中的研究方向和前景进行了展望。     

柔嫩艾美耳球虫地克珠利与马杜拉霉素抗药株的基因重组选育

将柔嫩艾美耳球虫地克珠利抗药株与马杜拉霉素抗药株等剂量同时感染无球虫鸡,再将得到的杂交后代经饲喂了地克珠利与马杜拉霉素的鸡筛选获得重组体,对该重组体的部分生物学特性进行了研究,旨在采用基因重组方法筛选出具有双重抗性的重组抗药株。结果显示,该重组体的重组率为0.4%;对地克珠利与马杜拉霉素具有完全抗性,而对氯苯胍与尼卡巴嗪完全敏感;卵囊繁殖能力介于两母株之间,致病性与母株无显著性差异。表明,用基因重组法首次成功筛选出了对地克珠利与马杜拉霉素同时具有抗性的柔嫩艾美耳球虫抗药株。     

Haplotypic blocks of X-linked STRs for forensic cases: study of recombination and mutation rates

In complex kinship cases, markers situated in haplotypic blocks may provide additional clues to other unlinked markers. We have established a protocol to amplify six X-chromosome microsatellites, located in two haplotype blocks, using PCR with fluorochrome-labeled primers and capillary electrophoresis. The segregation stability was explored in 92 unrelated families with individuals from three generations. Sixty-one different haplotypes were found in the DXS10079-DXS10074-DXS10075 block in the grandfathers and 96 in the mothers, with estimated haplotype diversities of 0.9828 and 0.9842, respectively. Fifty and 73 different haplotypes were found in the DXS6801-DXS6809-DXS6789 block in the grandfathers and the mothers, with estimated haplotype diversities of 0.9711 and 0.9742, respectively. We observed 10 between-cluster and one within-cluster recombinations in 99 female meioses. The overall per-locus mutation rate was 0.0034. This protocol allows for the characterization of the alleles of two sets of linked markers of the X-chromosome that can be useful in complex forensic cases.     

应用CT三维重组技术判定胸骨性别的研究

目的建立利用三维重组形态学指标判定胸骨性别来源的方法,并对其判定效果进行评价,考察虚拟骨骼的法医学应用价值。方法应用胸部螺旋CT扫描图像,通过多层面重组法获取胸骨的二维影像,结合容积再现技术得出的三维模型,分别测量胸骨的全长、柄长、体长、柄最大宽、体最大宽、柄最大厚、体最大厚、体上端厚等8项指标,并计算出3个比值指标;筛选出其中有性别差异的指标,建立性别判别方程并评价其判别效果。结果 11个指标的性别差异均具有统计学意义(P0.05),但以胸骨全长、胸骨体长、体最大厚及柄最大宽的判别效果较好。所建方程组中,全指标、长度指标判别方程及逐步判别方程的判别率较高,88.6%的判定率与近期国外有关性别判定研究的报道结果基本一致。结论应用多层螺旋CT三维重组技术判定国人胸骨性别具有较高的可行性和准确性,该技术有望应用于胸骨年龄推断及其它虚拟骨骼的研究。     

Bacterial Profiling of Soil Using Genus‐Specific Markers and Multidimensional Scaling*

Abstract: Forensic identification of soil based on microbial DNA fingerprinting has met with mixed success, with research efforts rarely considering temporal variability or local heterogeneity in soil’s microbial makeup. In the research presented, the nitrogen fixing bacteria rhizobia were specifically examined. Soils were collected monthly from five habitats for 1 year, and quarterly in each cardinal direction from the main collection site. When all habitats were compared simultaneously using Terminal Restriction Fragment Length Polymorphism analysis of the rhizobial recA gene and multidimensional scaling, only two were differentiated over a year’s time, however pairwise comparisons allowed four of five soils to be effectively differentiated. Adding in 10‐foot distant soils as “questioned” samples correctly grouped them in 40–70% of cases, depending on restriction enzyme used. The results indicate that the technique has potential for forensic soil identification, although extensive anthropogenic manipulation of a soil makes such identification much more tentative.     

减毒鸡白痢沙门氏菌ΔcrpC79-13株的构建及其对雏鸡的免疫活性

为构建鸡白痢沙门氏菌C79-13株Δcrp基因缺失突变株,并初步观察ΔcrpC79-13缺失菌株作为活疫苗对雏鸡的免疫活性,将含缺失320bp crp基因的重组自杀性质粒pREΔcrp与C79-13进行接合转移,两步法筛选出无抗性标记的ΔcrpC79-13缺失菌株;通过半数致死量测定其毒力;给4日龄雏鸡口服免疫缺失菌株,在不同时间点根据胸腺、法氏囊、脾等免疫器官发育和平均日增重、外周血淋巴细胞转化试验、Griess法NO测定及血清IgG动态观察免疫水平。结果显示ΔcrpC79-13的毒力较C79-13降低约99.6%(LD50>5.0×109CFU);雏鸡接种ΔcrpC79-13(1.0×109 CFU/只)后不影响雏鸡生长,第14～21天体内特异性细胞和体液免疫水平达到最高。表明成功构建了减毒鸡白痢沙门氏菌ΔcrpC79-13株,其毒力显著降低,免疫雏鸡安全,具有良好的免疫活性。