HIV-1B亚型核心蛋白gag基因真核表达载体的构建及其在HepG2细胞中的表达

目的克隆人类免疫缺陷病毒Ⅰ型B亚型核心蛋白gag基因,构建真核表达载体,并在真核细胞中表达,为进一步制备自行设计的以λ噬菌体作为载体的HIV核酸疫苗奠定基础。方法以克隆好的HIV1B亚型U26942全基因质粒DNA作为模板,根据Genbank中gag基因的核苷酸序列设计引物,并在引物的5’端分别引入BamHⅠ及XhoⅠ酶切位点,特异性的扩增gag基因。TA克隆后经双酶切、测序等鉴定重组质粒,再经双酶切、连接构建含gag编码基因的真核表达载体,并进行酶切鉴定分析pcDNA3.1(+)/gag。在脂质体介导下转染HepG2细胞,经G418压力筛选建立稳定转染gag基因的细胞系,用RT PCR及Western印迹检测其在HepG2细胞中的表达。结果重组质粒经BamHⅠ、XhoⅠ双酶切成5.4kb与1.5kb的片断,表明表达载体pcDNA3.1(+)中插入了gag基因片断,测序结果表明编码框正确。RT PCR及Western印迹证实稳定转染gag基因的HepG2细胞系中有该基因的表达。结论成功构建了HIV1B亚型核心蛋白gag基因的真核表达载体pcDNA3.1(+)/gag,并在HepG2细胞中获得稳定表达。     

弓形虫致密颗粒蛋白GRA2真核表达质粒的构建与体外表达

目的构建弓形虫致密颗粒蛋白GRA2的真核表达重组质粒。方法设计合成GRA2引物，运用PCR方法扩增其基因片段，经克隆至pMDl8-T载体后，亚克隆至真核表达质粒pcDNA3．1（-）而构建重组表达质粒pcDNA3．1-GRA2。脂质体法将构建的重组质粒转染HFF细胞，RT—PCR法检测转染细胞中GRA2的表达情况。结果PCR扩增GRA2基因序列正确，构建的重组表达质粒pcDNA3．1-GRA2经PCR、EcoRⅠ／HindⅢ双酶切和测序鉴定正确；转染GRA2基因的细胞，RT—PCR可见目的条带。结论成功获得真核表达重组质粒pcDNA3．1-GRA2，为进一步研究弓形虫疫苗的免疫保护性奠定基础。     

SV40T抗原胃壁细胞特异性表达载体的构建与鉴定

目的:构建在胃壁细胞中特异性表达SV40T抗原的真核表达裁体并进行鉴定.方法:采用酚-氯仿法从昆明小鼠肝细胞中提取基因组DNA,聚合酶链式反应(PCR)扩增H~ /K~ ATPaseβ亚基启动子,产物命名为HK.将PCR产物纯化回收后与pMT18-T载体相连,并将其克隆至真核表达载体pcDNA3.1(-),构建pcDNA3.1(-)/HK;从含SV40T基因片段的质粒p LITAg中酶切回收SV40T基因,与pcDNA3.1(-)/HK相连,构建胃壁细胞特异性表达载体pcDNA3.1(-)/HKSV,并测序鉴定.结果:pcDNA3.1(-)/HKSV用XbaⅠ、BarnHⅠ双酶切可得到1kb H~ /K~ ATPaseβ亚基启动子,2.7 kb SV40T基因与5.4 kb pcDNA3.1(-)载体3条DNA条带.用XbaⅠ、KpnⅠ双酶切电泳,可见到约3.7与5.4 kb的两条DNA条带;用BamHⅠ单酶切电泳,可见到2.7与6.4 kb的2条DNA条带;用EcoRⅠ单酶切,只见到约9.1 kb的1条DNA条带,酶切电泳结果均与设计一致.测序结果显示,H~ /K~ ATPaseβ亚基启动子与SV40T基因成功构建于pcDNA3.1(-)真核表达载体中.结论:构建在胃壁细胞中特异性表达SV40T基因的真核表达载体,为进一步转基因小鼠及胃癌动物模型的建立提供了稳定、可靠的分子工具.     

鼠反义转化生长因子βⅠ型受体真核表达质粒的构建与鉴定

目的:构建鼠反义转化生长因子βⅠ型受体(TβRⅠ)基因pcDNA3.1( )真核表达质粒,为进一步研究通过TβRⅠ干预肝纤维化的发生发展提供实验基础.方法:将取冰冻保存的大鼠肝组织,应用TRIzol法提取总RNA,琼脂糖凝胶电泳检测RNA完整性,并用紫外分光核酸蛋白分析仪测定RNA浓度和纯度.使用一步法逆转录聚合酶链反应(RT-PCR)试剂盒获得目的基因TβRⅠcDNA片段,采用巢式PCR扩增TβRⅠ基因片断.用CaCl2法诱导感受态细胞.将真核表达载体pcDNA3.1( )在多克隆位点处用EcoRⅠ、XholⅠ双酶切线性化,切胶纯化回收;TβRⅠ基因片断双酶切后切胶纯化回收;将纯化回收的pcDNA3.1( )线性化载体和TβRⅠ基因片段定向及反向连接,构建以pcDNA3.1( )为载体的反义TβRⅠ基因真核表达质粒.转化JM109大肠杆菌.酶切证实的阳性克隆行测序分析.结果:琼脂糖凝胶电泳检测RNA完整性,见28S,18S条带完整,而且28S条带亮度为18S的1倍左右,认为RNA完整性良好;并用紫外分光核酸蛋白分析仪测定RNA纯度A260/A280=1.9150,认为RNA纯度良好;RNA浓度为770mg/L.阳性克隆质粒经双酶切后行10g/L琼脂糖凝胶电泳在DNAMarker430bp和线性化纯化后pcDNA3.1( ),5.3kb附近可见两条明显条带,与所需目的片段大小相符,证实为阳性克隆,重组质粒构建成功.DNA测序结果与预期目的片段序列一致.结论:鼠反义TβRⅠ/pcDNA3.1( )真核表达重组质粒构建成功.     

HBx基因真核表达载体的构建及表达

目的 构建重组HBx蛋白的真核表达载体pIRES2-AcGFP-HBx.方法 设计合成HBx基因的特异性PCR引物.PCR扩增获得HBx基因序列;将HBx基因序列克隆人T载体(pGEM-T-HBx);再用限制性内切酶BglⅡ和EcoR Ⅰ双酶切下目的片段,将其亚克隆人真核表达载体pIRES2-AcGFP;双酶切(Bgl Ⅱ和EcoR Ⅰ)和序列测定鉴定重组子;脂质体包裹pIRES2-AcGFP-HBx转染入HepG2细胞,G418筛选得到稳定表达HBx的细胞克隆,Western blot检测HBx蛋白在转染细胞中的表达情况.结果 PCR扩增获得全长HBx基因序列;双酶切筛选得到阳性重组子,测序分析证实插入序列正确;转染plRES2-AcGFP-HBx的HepG2细胞,荧光显微镜可观察到GFP的表达,Western blot 证实表达HBx蛋白.结论 成功构建重组HBx基因真核表达载体,获得稳定表达HBx蛋白的HepG2细胞株,为深入研究HBx蛋白的生物学功能提供实验条件.     

pEGFP?N1?HBsAg?ROP2多基因重组表达质粒的构建及表达鉴定

目的 构建pEGFP?N1?HBsAg?ROP2重组质粒,并转染HEK293T细胞进行表达鉴定,为弓形虫病核酸疫苗的研制奠定基础。 方法 根据HBsAg基因序列和pcDNA3?p30?ROP2重组质粒酶切位点设计引物,PCR扩增HBsAg基因,经酶切、连接、转化,利用HBsAg基因替换p30基因,构建pcDNA3?HBsAg?ROP2重组质粒;经HindⅢ和KpnⅠ双酶切,将HBsAg?ROP2片段与pEGFP?N1真核表达载体相连,构建pEGFP?N1?HBsAg?ROP2重组表达质粒,转染HEK293T细胞,观察其蛋白表达水平。结果 HBsAg片段PCR产物约700 bp,与理论值相符;构建pcDNA3?HBsAg?ROP2重组质粒,双酶切电泳后得到约5.4 kb和1.9 kb的两条带,与预期结果相符。pEGFP?N1?HBsAg?ROP2双酶切后产生约4.7 kb和1.9 kb的条带,经测序鉴定,与GenBank发表的序列同源性为99.84%。目的基因已成功转染入HEK293T细胞中,且正确表达,蛋白浓度为3.08 mg/ml。结论 成功构建pEGFP? N1?HBsAg?ROP2重组表达质粒,转染HEK293T细胞能正确表达。     

日本血吸虫酪氨酸羟化酶基因的克隆、真核表达及鉴定

目的扩增日本血吸虫的酪氨酸羟化酶（Schistosoma japonicum Tyrosine Hydroxylase,SjTH）编码基因,构建pcDNA3.1(+) SjTH真核表达载体,并检测其在COS 7细胞中的表达情况。方法以日本血吸虫成虫cDNA为模板,RACE PCR扩增SjTH编码基因,并与pGEM T连接进行亚克隆,双酶切后回收目的基因,并与真核表达载体pcDNA3.1(+)连接,PCR和双酶切初步鉴定后测序,纯化无内毒素重组质粒pcDNA3.1(+) SjTH,转染入COS 7细胞,G418筛选阳性克隆,RT PCR和Western blot鉴定重组SjTH蛋白的表达。结果RACE PCR 扩增出SjTH编码基因,大小约1 392bp,经双酶切鉴定、测序及Blast分析鉴定重组真核质粒构建成功。脂质体介导无内毒重组真核质粒pcDNA3.1(+) SjTH转染入COS 7细胞,G418筛选出阳性克隆,RT PCR证实阳性单克隆细胞带有SjTH编码基因,Western blot鉴定单克隆细胞表达重组SjTH蛋白,大小约54kD。结论真核表达载体pcDNA3.1(+) SjTH构建成功,G418筛选出阳性克隆,真核表达重组SjTH蛋白,为后续研究SjTH蛋白功能奠定基础。     

pcDNA3.1-HIF-1α重组质粒的构建及其初步鉴定

目的 探讨HIF-1 α与前列腺癌发病机制之间相关性提供研究工具.方法 采用Trizol法裂解细胞,提取HIF-1 α且以该RNA为模板逆转录为cDNA,然后行PCB处理扩增HIF-1 α基因功能片段区域,克隆至真核表达载体pcDNA3.1上,转化至大肠杆菌DH-5 α,小提质粒,酶切凝胶电泳鉴定,序列测定,经鉴定为正确序列后中抽质粒,采用Fugene试剂转染至前列腺癌细胞PC-3,经G418筛选,建立稳定表达HIF-1 α的前列腺癌细胞系pcDNA3-1-HIF-1 α-PC-3,采用Western印迹鉴定重组质粒的表达.结果 PCR扩增基因片段大小为2.89 kb,克隆至真核载体pcDNA3.1,酶切凝胶电泳可见两个条带,大小大约为5.3 kb和2.89 kb,与预期的大小相符合,序列测定与Cenbank公布的一致,Western印迹验证其在细胞内能表达.结论 重组质粒pcDNA3.1-HIF-1 α能够在前列腺癌PC-3表达,构建成功,为研究HW-1α与前列腺癌提供了一个工具.     

刚地弓形虫RH株ROP11基因的克隆与真核表达载体的构建北大核心CSCD

目的构建刚地弓形虫(Toxoplasma gondii)棒状体蛋白11(ROP11)的真核表达重组质粒并在真核细胞中表达目的蛋白。方法设计合成弓形虫ROP11基因引物,运用RT-PCR方法扩增ROP11基因并克隆至真核表达质粒pcDNA3.1(+),构建重组表达质粒pcDNA3.1-ROP11。将重组质粒转染HeLa细胞,采用间接免疫荧光法检测目的蛋白表达。结果 RT-PCR扩增弓形虫ROP11基因片段为1 548bp,与预期大小相符。构建的重组质粒pcDNA3.1-ROP11经PCR及EcoRⅠ和NotⅠ双酶切鉴定正确。重组质粒测序后与GenBank报道的ROP11基因比对,核苷酸序列同源性和推导氨基酸序列同源性均为99%。免疫荧光检测显示,在重组质粒转染的HeLa细胞胞浆观察到黄绿色荧光,对照组无荧光。结论成功构建了真核表达质粒pcDNA3.1-ROP11,该重组质粒能够在真核细胞中表达目的蛋白,为弓形虫核酸疫苗的研制奠定了基础。     

Different RBC aggregating properties of the Aalpha2Bbeta2gammaA2 and Aalpha2Bbeta2gammaAgamma' subpopulations of human fibrinogen

Human fibrinogen (TF) has been separated into two fractions: F1 - homodimers with respect to the gamma chain, and F2 - heterodimers composed of gammaA and gamma' polypeptides. Their rouleaux-inducing properties were as follows: (1) both, at the same concentration of 0.8%, were less effective than TF; (2) F1 produced larger rouleaux even under static conditions of a hemocytometer where F2 was silent; (3) F2 induced the process when a suspension was gently sheared between microscopic slides. Since the synthetic peptide gamma'(414-427) inhibited the rouleau formation in a mixture with F2, the C-terminal amino acids of the gamma' polypeptide probably bind the molecule to the cell. The inhibition was feebly visible in the native ratio of F1/F2, implicating a compensatory effect of F1.     

Characterization of two types of fetal hemoglobin: alpha 2G gamma 2 and alpha 2A gamma 2

The effect of differences in G gamma and A gamma fractions of fetal hemoglobin (HbF) on the kinetics of polymerization of HbS-HbF mixtures was studied. We also examined their effect on oxygen affinity, surface hydrophobicity, mechanical stability, and solubility of HbF. Differences in G gamma:A gamma ratio did not affect the polymerization of mixtures of HbF and HbS, suggesting that the inhibitory effect of HbF on the polymerization of HbS is independent of the G gamma:A gamma ratio of HbF and is totally dependent on the fraction of HbF in the mixture. The oxygen equilibrium curve of HbF was not affected by differences in the ratios of G gamma and A gamma in HbF. In contrast, surface hydrophobicity, mechanical stability, and solubility of HbF were affected by differences in the G gamma:A gamma ratio. The higher the G gamma:A gamma ratio, the smaller the elution volume on a TSK Gel SW hydrophobic column in high phosphate buffer. The mechanical stability of HbF was also dependent on the ratio of G gamma:A gamma; stability was greater at higher fractions of A gamma. Differences in the G gamma:A gamma ratio also affected solubility of HbF: HbF containing the higher fraction of G gamma was the more soluble. These data indicate that although alanine at the 136th position of the gamma chains has a stronger surface hydrophobicity than does glycine, this difference does not affect either the polymerization of HbS or the oxygen affinity of HbF.     

Structure-function of Hb Marseille-Long Island [alpha 2 beta 2 N-methionyl-2(NA2) His----Pro

Suspensions of red cells containing Hb Marseille-Long Island showed decreased oxygen affinity and low interaction with 2,3-diphosphoglycerate. Oxygen equilibrium studies of the purified component confirmed these abnormalities. Oxidation rate measurements of carbonmonoxy-Hb Marseille and carbonmonoxy-Hb A by ferricyanide showed an increased rate for the former, suggesting an increased dissociation constant for carbon monoxide. Nuclear Magnetic Resonance spectra in the high field region revealed small changes in the proximal region of the heme pocket. These results indicated that the mutation causes a perturbation at a distance from the mutation site.     

Classification and characterization of hereditary types 2A, 2B, 2C, 2D, 2E, 2M, 2N, and 2U (unclassifiable) von Willebrand disease.

All variants of type 2 von Willebrand disease (VWD) patients, except 2N, show a defective von Willebrand factor (VWF) protein (on cross immunoelectrophoresis or multimeric analysis), decreased ratios for VWF:RCo/Ag and VWF:CB/Ag and prolonged bleeding time. The bleeding time is normal and FVIII:C levels are clearly lower than VWF:Ag in type 2N VWD. High resolution multimeric analysis of VWF in plasma demonstrates that proteolysis of VWF is increased in type 2A and 2B VWD with increased triplet structure of each visuable band (not present in types 2M and 2U), and that proteolysis of VWF is minimal in type 2C, 2D, and 2E variants that show aberrant multimeric structure of individual oligomers. VWD 2B differs from 2A by normal VWF in platelets, and increased ristocetine-induced platelet aggregation (RIPA). RIPA, which very likely reflects the VWF content of platelets, is normal in mild, decreased in moderate, and absent in severe type 2A VWD. RIPA is decreased or absent in 2M, 2U, 2C, and 2D, variable in 2E, and normal in 2N. VWD 2M is usually mild and characterized by decreased VWF:RCo and RIPA, a normal or near normal VWF multimeric pattern in a low resolution agarose gel. VWD 2A-like or unclassifiable (2U) is distinct from 2A and 2B and typically featured by low VWF:RCo and RIPA with the relative lack of high large VWF multimers. VWD type 2C is recessive and shows a characteristic multimeric pattern with a lack of high molecular weight multimers, the presence of one single-banded multimers instead of triplets caused by homozygosity or double hereozygosity for a mutation in the multimerization part of VWF gene. Autosomal dominant type 2D is rare and characterized by the lack of high molecular weight multimers and the presence of a characteristic intervening subband between individual oligimers due to mutation in the dimerization part of the VWF gene. In VWD type 2E, the large VWF multimers are missing and the pattern of the individual multimers shows only one clearly identifiable band, and there is no intervening band and no marked increase in the smallest oligomer. 2E appears to be less well defined, is usually autosomal dominant, and accounts for about one third of patients with 2A in a large cohort of VWD patients.     

Experimental Investigation of Radiation Shielding Competence of Bi2O3-CaO-K2O-Na2O-P2O5 Glass Systems

The gamma-ray shielding features of Bi₂O₃-CaO-K₂O-Na₂O-P₂O₅ glass systems were experimentally reported. The mass attenuation coefficient (MAC) for the fabricated glasses was experimentally measured at seven energy values (between 0.0595 and 1.33 MeV). The compatibility between the practical and theoretical results shows the accuracy of the results obtained in the laboratory for determining the MAC of the prepared samples. The mass and linear attenuation coefficients (MACs) increase with the addition of Bi₂O₃ and A4 glass possesses the highest MAC and LAC. A downward trend in the linear attenuation coefficient (LAC) with increasing the energy from 0.0595 to 1.33 MeV is found. The highest LAC is found at 1.33 MeV (in the range of 0.092–0.143 cm⁻¹). The effective atomic number (Z_eff) follows the order B1 > A1 > A2 > A3 > A4. This order emphasizes that increasing the content of Bi₂O₃ has a positive effect on the photon shielding proficiencies owing to the higher density of Bi₂O₃ compared with Na₂O. The half value layer (HVL) is also determined and the HVL for the tested glasses is computed between 0.106 and 0.958 cm at 0.0595 MeV. The glass with 10 mol% of Bi₂O₃ has lower HVL than the glasses with 0, 2.5, 5, and 7.5 mol% of Bi₂O₃. So, the A4 glass needs a smaller thickness than the other glasses to shield the same radiation. As a result of the reported shielding parameters, inserting B₂O₃ provides lower values of these three parameters, which in turn leads to the development of superior photons shields.