Kozak序列对TIMP1基因在人乳腺癌细胞MCF-7中表达的影响

目的探讨Kozak序列对基质金属蛋白酶抑制剂1(TIMP1)基因在人乳腺癌细胞MCF-7中表达的影响。方法构建pcDNA3.1-TIMP1和pcDNA3.1-TIMP1-K(含有Kozak序列)重组真核表达质粒,用FugeneHD转染试剂将重组表达质粒转染MCF-7细胞,采用荧光定量PCR和Western blot检测pcDNA3.1-TIMP1和pcDNA3.1-TIMP1-K在MCF-7细胞中表达的差异。结果重组真核表达质粒经PCR、双酶切及测序鉴定,证明构建正确。质粒pcDNA3.1-TIMP1-K转染细胞比空白对照细胞TIMP1基因mRNA表达量高约0.95倍,蛋白表达量高0.43倍;而质粒pcDNA3.1-TIMP1转染细胞比空白对照细胞mRNA表达量高0.37倍,蛋白表达量高0.25倍。结论质粒pcDNA3.1-TIMP1-K与pcDNA3.1-TIMP1在MCF-7细胞中mRNA和蛋白表达水平均存在差异,Kozak序列提高了TIMP1基因的表达。     

P4HB基因真核表达质粒的构建及在人肺腺癌A549细胞中的表达

目的构建人P4HB基因真核表达质粒,并检测其在人肺腺癌A549细胞中的表达。方法采用RT-PCR法从正常人肝细胞HL7702中扩增P4HB基因片段,插入真核表达载体pcDNA3.1(+),构建重组真核表达质粒pcDNA3.1-P4HB,在脂质体LipofectamineTM 2000介导下转染A549细胞,通过G418加压筛选,建立稳定转染细胞系,通过qPCR和Western blot法检测转染细胞中P4HB基因mRNA的水平及蛋白的表达水平。结果重组真核表达质粒pcDNA3.1-P4HB经双酶切(BamHⅠ/EcoRⅠ)和测序证实构建正确;质粒pcDNA3.1-P4HB转染的A549细胞中P4HB基因mRNA的水平为空载体转染的细胞和未转染细胞的102倍;质粒pcDNA3.1-P4HB转染的A549细胞中P4HB蛋白的表达量(1.71)较未转染的A549细胞(1.11)明显升高。结论成功构建了P4HB基因真核表达质粒pcDNA3.1-P4HB,转染A549细胞后,P4HB基因在mRNA水平和蛋白水平均出现了较强的表达,表明P4HB基因已稳定转染入A549细胞中。本实验为进一步研究P4HB对人肺癌细胞增殖、侵袭和转移能力的影响奠定了基础。     

FABP7基因真核表达载体的构建及其对人乳腺癌细胞MCF-7增殖的影响

目的构建脑脂肪酸结合蛋白(BLBP/B-FABP,FABP7)基因的真核表达载体,并检测其对人乳腺癌细胞MCF-7增殖的影响。方法采用逆转录方法从星型细胞瘤组织中扩增FABP7基因,双酶切后插入线性化的pcDNA3.1载体真核启动子下游,构建重组真核表达载体,转染人乳腺癌细胞MCF-7后,采用半定量RT-PCR检测FABP7基因mRNA的表达,MTT法检测细胞的增殖活性、流式细胞术检测细胞的周期变化情况,并对细胞进行计数。结果FABP7基因重组真核表达质粒经双酶切及测序鉴定证明构建正确,转染MCF-7细胞后48、72和96h,pcDNA3.1-FABP7组的细胞数和细胞的A490值均比pcDNA3.1空质粒组明显降低,G1期细胞百分含量均明显升高。结论已成功构建了FABP7基因的真核表达载体,该载体可抑制人乳腺癌细胞MCF-7的增殖。     

人叉头转录因子O亚型3基因重组表达质粒的构建及鉴定

目的构建人叉头转录因子O亚型3(forkhead box class O3,FOXO3)基因重组表达质粒,并检测其在人外周血单个核细胞(peripheral blood mononuclear cell,PBMC)中的表达。方法利用3对引物从人cDNA中分别扩增大小为382、829和891 bp的3个目的片段,胶回收后进行拼接,获得hFOXO3的CDS片段,与pcDNA3.1(+)载体连接,构建重组表达质粒pcDNA3.1(+)-hFOXO3,转染人PBMC,采用Real-time PCR和Western blot分别检测hFOXO3基因mRNA水平及蛋白表达水平。结果重组表达质粒经双酶切及测序证实构建正确;转染PBMC后,pcDNA3.1(+)-hFOXO3组hFOXO3基因mRNA的水平分别为转染试剂对照组和pcDNA3.1(+)组的2 599.7和2 377.8倍,且差异均有统计学意义(P0.001);pcDNA3.1(+)-hFOXO3组hFOXO3蛋白的表达水平分别为转染试剂对照组和pcDNA3.1(+)组的2和1.8倍,且差异均有统计学意义(P0.01);而转染试剂对照组和pcDNA3.1(+)组间hFOXO3基因mRNA水平和蛋白的表达水平差异均无统计学意义(P0.05)。结论成功构建了pcDNA3.1(+)-hFOXO3重组表达质粒,其在人PBMC中能进行hFOXO3基因mRNA的转录及蛋白的表达,为进一步研究hFOXO3的生物学功能及其作用机制奠定了基础。     

JTV1基因真核表达质粒的构建及其在K562细胞中的表达

目的 构建JTV1基因真核表达质粒并稳定转染人白血病细胞系K562,检测转染细胞中JTV1基因mRNA和蛋白的表达水平及其对K562细胞增殖的影响。方法从人外周血单个核细胞中克隆JTV1基因,并将其插入pcDNA3.1表达载体中,构建真核重组表达质粒pcDNA3.1-JTV1,经脂质体介导转染K562细胞,采用RT-PCR和Western blot法鉴定转染细胞中JTV1基因mRNA和蛋白的表达水平;MTT法检测JTV1稳定表达对K562细胞增殖的影响。结果重组表达质粒pcDNA3.1-JTV1经双酶切及测序证实,目的基因已插入质粒中;人JTV1基因能在K562细胞中稳定表达;JTV1具有抑制K562细胞增殖的作用。结论已成功构建了JTV1基因真核表达质粒,并获得了稳定表达人JTV1基因的K562细胞克隆,为进一步研究人JTV1基因的功能及其与白血病细胞增殖及凋亡的相关性提供了细胞模型。     

锌指抗病毒蛋白基因真核表达质粒的构建及其在HepG2细胞中的表达

目的构建锌指抗病毒蛋白(zinc finger antiviral protein,ZAP)基因真核表达质粒,并在人肝癌细胞系HepG2细胞中表达。方法化学合成含第4个CCCH锌指基序的ZAP基因片段,经PCR扩增后,插入pcDNA3.1(+)载体,并在ZAP下游插入报告基因EGFP,构建重组表达质粒pcDNA3.1(+)-ZAP/EGFP。在脂质体Genfectin介导下将重组表达质粒转染HepG2细胞,转染后24 h,荧光显微镜观察EGFP的表达;转染后48 h,RT-PCR法检测转染细胞中ZAP基因和内参GAPDH基因mRNA的转录。结果重组表达质粒pcDNA3.1(+)-ZAP/EGFP经双酶切和测序证实构建正确;转染后24 h,pcDNA3.1(+)-ZAP/EGFP质粒转染的HepG2细胞在荧光显微镜蓝色激发光下可见胞质内有较强的黄绿色荧光;转染后48 h,pcDNA3.1(+)-ZAP/EGFP质粒转染的HepG2细胞可扩增出288 bp的ZAP基因条带和100 bp的内参GAPDH基因条带。结论成功构建了含第4个CCCH锌指基序的ZAP基因真核表达质粒,并在HepG2细胞中获得表达,为下一步深入研究ZAP对肝炎病毒是否具有抗病毒作用以及利用ZAP作为抗病毒治疗的一种新手段奠定了基础。     

重组质粒pcDNA3.1-Her2-hsp70的构建及其表达

目的构建重组表达质粒pcDNA3.1-Her2-hsp70,并筛选稳定表达Her2蛋白的细胞株。方法采用RT-PCR法扩增人乳腺癌SKBR-3细胞中Her2和hsp70基因,插入质粒pcDNA3.1中,构建重组表达质粒pcDNA3.1-Her2、pcDNA3.1-hsp70,经双酶切后,回收hsp70基因,连接入质粒pcDNA3.1-Her2的N-末端,构建重组表达质粒pcDNA3.1-Her2-hsp70。将质粒pcDNA3.1和pcDNA3.1-Her2-hsp70分别转染小鼠乳腺癌4T-1细胞,采用Western blot法检测Her2蛋白的表达。结果重组表达质粒pcDNA3.1-Her2、pcDNA3.1-hsp70及pcDNA3.1-Her2-hsp70经双酶切鉴定,证明构建;转染质粒pcDNA3.1-Her2-hsp70的4T-1细胞中可见相对分子质量约65 000的Her2蛋白的表达。结论已成功构建了重组质粒pcDNA3.1-Her2、pcDNA3.1-hsp70及pcDNA3.1-Her2-hsp70,并获得了稳定表达Her2蛋白的小鼠乳腺癌4T-1细胞,为进一步探讨佐剂辅助异种抗原产生的抗肿瘤免疫效应奠定了基础。     

成纤维细胞生长因子受体基因野生型和E731K突变型真核表达质粒的构建及鉴定

目的构建成纤维细胞生长因子受体(fibroblast growth factor receptor 2,FGFR2)基因野生型和E731K突变型的真核表达载体,并进行鉴定。方法利用基因定点突变试剂盒,定点突变FGFR2基因,获得其E731K突变的突变型基因,通过设计含有XbaⅠ、XhoⅠ限制性内切酶识别序列的引物分别扩增FGFR2基因野生型和E731K突变型的cDNA,克隆至质粒pcDNA3.1-EGFP上,构建重组表达质粒pcDNA3.1-FGFR2-EGFP和pcDNA3.1-FGFR2E731K-EGFP,利用X-tremeGENE HP DNA将质粒转染至HEK293细胞,采用实时荧光定量PCR法及Western blot法检测FGFR2表达水平。结果经定点突变已获得野生型的突变型FGFR2基因,碱基序列与设计序列完全一致,cDNA第2191位碱基G突变为A。重组表达质粒pcDNA3.1-FGFR2-EGFP和pcDNA3.1-FGFR2E731K-EGFP经双酶切及测序鉴定证明构建正确。质粒转染HEK293细胞后,荧光显微镜下均可见绿色荧光蛋白表达;质粒pcDNA3.1-FGFR2-EGFP和pcDNA3.1-FGFR2E731K-EGFP转染组中FGFR2 mNRA和蛋白表达水平均明显高于质粒pcDNA3.1-EGFP转染组和空白对照组(P0.05)。结论成功构建了FGFR2基因野生型和E731K突变型的真核表达质粒,并在HEK293细胞中成功表达,为进一步研究FGFR2基因奠定了基础。     

人CD52基因的克隆及稳定转染细胞系的建立

目的克隆人CD52基因,构建真核表达载体,并在CHO细胞中稳定表达。方法提取人Hut-78细胞总RNA,采用RT-PCR法扩增CD52基因,定向克隆至真核表达载体pcDNA3.1(+),构建重组表达质粒pcDNA3.1(+)/CD52,通过脂质体法转染CHO细胞,建立稳定转染的细胞系CHO-CD52。采用RT-PCR、免疫荧光组化技术及流式细胞术检测目的基因和蛋白的表达。结果 RT-PCR扩增得到186bp的DNA片段。重组表达质粒pcDNA3.1(+)/CD52经PCR、双酶切及测序证明构建正确。CHO-CD52细胞经RT-PCR分析,可见186bp的目的基因条带;经免疫荧光检测,可见绿色荧光分布;经流式细胞术分析,阳性细胞百分率及荧光平均值分别为98.18和193.56。结论已成功克隆了人CD52基因,并建立了稳定转染的CHO细胞系,为CD52单克隆抗体的制备及抗体药物的开发奠定了基础。     

人T-bet和HBV-L共表达质粒的构建及体外表达

目的构建人转录因子T-bet基因与乙肝病毒表面抗原大蛋白全长基因(hepatitis B virus surface antigen large protein,HBV-L)的共表达载体,并检测其在体外的表达。方法利用PCR及基因重组技术,以人外周血单个核细胞(peripheral blood mononuclear cell,PBMC)的cDNA为模板,扩增获得人T-bet全长基因,以含有HBV-L的质粒pcDNA3.1-HBV-L为模板,扩增获得HBV-L基因,将上述2个基因克隆至真核表达质粒p IRES中,获得共表达质粒p IRES-T-bet-HBV-L。将该质粒转染293T细胞,经RT-PCR、ELISA和细胞免疫荧光试验检测其在真核细胞中的表达。结果限制性酶谱分析及测序证实重组质粒p IRES-T-bet-HBV-L构建成功;该质粒在体外转染293T细胞后,可表达T-bet与HBV-L两者的mRNA;细胞免疫荧光试验和ELISA检测结果证实,该质粒转染293T细胞后可表达T-bet和HBV-L蛋白。结论成功构建了共表达质粒pIRES-T-bet-HBV-L,该质粒能在293T细胞中表达。     

Study of human cortical bone and demineralized human cortical bone viscoelasticity

The knowledge of human bone viscoelasticity is an important issue for defining semirigid calcified tissues implants. A very sensitive technique was used to investigate bone viscoelasticity: the thermally stimulated creep method. A study of demineralized human bone was performed to determine the molecular origin of bone viscoelasticity. The thermally stimulated creep spectra of bone and demineralized bone, at the hydrated state, present a similar shape with one main retardation mode located at −133 and −120°C, respectively. This mode is shifted toward higher temperatures after dehydration, revealing the existence of another mode at around −155°C. The analysis of elementary spectra of bone and demineralized bone has shown that retardation times follow an Arrhenius equation, and that two compensation phenomena are observed with comparable compensation parameters. The first compensation phenomenon, which corresponds to the main retardation mode, was attributed to motions of water molecules located inside the collagen triple helix. The second compensation phenomenon, which reveals the existence of another relaxation mode at higher temperatures, was assigned to movements of hydrophilic side chains bound to water molecules. As for the mode observed at around −155°C, it was associated with motions of aliphatic side chains. Overall, bone viscoelasticity originates from the organic matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2527–2533, 2001     

静注人免疫球蛋白制剂抗巨细胞病毒中和抗体效价的筛查

目的筛查国内、外静注人免疫球蛋白(human intravenous immunoglobulin,IVIG)和静注巨细胞病毒人免疫球蛋白(human intravenous cytomegalovirus immunoglobulin,CMV-IVIG)制品抗CMV中和抗体效价。方法采用微量细胞病变法检测国内、外IVIG制品及CMV-IVIG抗CMV中和抗体效价,并进行比较。结果国外CMV-IVIG制品Cytogam(3 648 U/g IgG)和Cytotect(3 104 U/g IgG)抗CMV中和抗体效价分别是IVIG制品Privigen(1 048 U/g IgG)和Intratect(980 U/g IgG)的3.5和3.2倍;国内CMV-IVIG制品抗CMV中和抗体平均效价(7 195 U/g IgG)是国内13家企业19批IVIG制品(1 836 U/g IgG)的3.9倍;国内IVIG制品抗CMV中和抗体平均效价是国外IVIG制品Privigen和Intratect的1.8和1.9倍,国内CMV-IVIG制品抗CMV中和抗体平均效价是国外CMV-IVIG制品Cytogam和Cytotect的2.0和2.3倍。结论国内、外的CMV-IVIG制品抗CMV中和抗体效价均为相应IVIG制品3倍以上,采用微量细胞病变法筛查血浆用于制备CMV-IVIG具有可行性,为CMV相关疾病的被动免疫制剂的制备提供了实验依据。     

Lipids in human milk

I have reviewed recent (March 1995–December 1997) papers on human milk lipids including many on fatty acid (FA) composition. The effects of maternal diets on the profiles are apparent. However, more data on the composition of milk lipids are needed. It is noteworthy that so few papers on milk FA composition have reported analyses using high-resolution gas-liquid chromatography columns. Two of these were on milk from women in North America. The diets in North America are varied and the number of analyses few. We do not have a reliable data base showing the ranges of biologically important acids. Except for the gangliosides, few new data on the other lipids appeared during this period.     

Paf-acether in human skin

Paf is a phospholipid mediator present in human skin which induces inflammatory events such as neutrophil infiltration and increased vascular permeability. Recent data suggest that cutaneous cells, such as fibroblasts and keratinocytes, produce paf and that paf is released during allergic cutaneous reactions. It is tempting to speculate that paf may contribute to the development of various skin disorders with acute and chronic skin inflammation. Paf antagonists may help in bringing answers to this hypothesis and may offer new prospects for the treatment of cutaneous inflammatory diseases. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Glycosphingolipids of human thyroid

Glycosphingolipids were isolated from total lipids of female and male human thyroids by alkaline hydrolysis, silicic acid, diethylaminoethyl-celluose and thin layer chromatography and analyzed by gas liquid chromatography. On the basis of their mobility in two dimensions on thin layer chromatography, IR analysis, and of sugar molar ratio, four neutral glycolipids, a sulfatide, and a hematoside fraction were identified. Glucosyl, plus galactosyl ceramide, and trihexosyl ceramide were the major fractions and accounted for 33% and 28% of total neutral glycolipids, respectively. Dihexosyl ceramide was a mixture of lactosyl and digalactosyl ceramide. The acidic lower phase glycolipids comprised ceramide galactosyl sulfate as the major component of male thyroids. Hematoside was identified tentatively as a minor component of the thyroids of both sexes. Major fatty acids of all neutral glycolipid fractions were 20∶0, 22∶0, 24∶0, and 24∶1; 24∶0 and 24∶1 for sulfatides. Low proportions of α-hydroxy fatty acids were identified. Total neutral glycosphingolipids of male thyroids were comparable in quantities with human liver but lower than kidneys, leucocytes, and platelets. Male thyroids comprised higher quantities of neutral glycosphingolipids (4.04±0.32 μmoles/g total lipid) as compared to females (2.34±0.21 μmoles/g total lipid), and much higher sulfatide than the females. These marked differences may suggest that the biosynthesis of the glycosphingolipids in the thyroid gland is under hormonal control. Similarities in glycosphingolipid composition of human thyroid and kidney are discussed in relation to a possible role played by glycolipids in ion transport, which is a common feature of the two organs.     

Lipids and human milk

To support the growth and development of the breast‐fed infant, human milk provides the dietary essential fatty acids, linoleic acid (LA; 18:2n‐6), α‐linolenic acid (ALA, 18:3n‐3), as well as longer‐chain polyunsaturated fatty acids including arachidonic acid (20:4n‐6) and docosahexanoic (DHA 22:6n‐3). The linoleic acid, alpha‐linolenic acid, DHA and arachidonic acid concentration of pasteurized and unpasteurized human milk remains stable during the first month of storage at –20°C and –80°C. However after the first month, a slow decrease in concentration progresses until the end of 6 months of storage at both temperatures. The levels of n‐6 and n‐3 fatty acids, particularly linoleic acid, alpha‐linolenic acid and DHA, in human milk vary widely within and among different populations, and are readily changed by maternal dietary intake of the respective fatty acid. The present paper reviews recent understanding from key researchers of maternal diet and human milk fat composition and form our work the effect of milk fat composition on storage conditions. It is important to understand that maternal diet can affect human milk fat composition and subsequently infant development and growth.     

Color and human response

Color has played an important role in human life and culture since the beginnings of recorded history. Here are random notes drawn from widely different sources.     

Fractography of human hair

The fracture behavior of human hair has been investigated with a view toward delineating fracture mechanisms that lead to different types of fracture under tensile loading. Principally, three types of fracture are encountered—smooth fractures, step fractures, and fractures involving undefined fibrillated ends. The moisture content of the fiber plays an important role in determining the type of fracture that occurs. Fiber conditioned at either low (～0%) or high (90%) relative humidity give predominantly smooth fractures, whereas those conditioned at intermediate relative humidities given predominantly step fractures. Surface treatments with polymers or surfactants do not seem to have any effect on the strength or the fracture behavior of fibers. At low moisture contents, fracture initiation occurs more often in the cortex, whereas, at high moisture contents, fracture almost always initiates at the surface of the fiber, suggesting that the swelling pressure of the cortex plays a significant role in fracture initiation. Fibers with larger cross-sectional areas tend to split along the axis because of the higher probability of encountering flaws or medullary cells which direct cracks along the fiber axis. Unlike synthetic polymeric fibers, hair fibers seem to follow the Griffith criterion of brittle fracture. This may be coincidental since electron microscopic evidence suggests that fracture propagation occurs by secondary cracks generated as a result of stress concentrations building up at the periphery of the primary crack. The rate of stress transfer to adjacent cortical cells via intercellular cement probably plays an important role in the fracture mechanism.