κ-卡拉胶邻苯二甲酰基化衍生物的抗氧化活性研究

对κ-卡拉胶进行酸降解得到三种卡拉胶低聚糖,并进一步与苯二甲酰基合成制得三种分子量分别为1450、2520和3430的κ-卡拉胶邻苯二甲酰衍生物(LA、LB和LC)。对产物进行IR表征并对其取代度(DS)进行测定,并检测了产物对羟基自由基.OH、DPPH自由基和过氧化氢的清除活性以及还原能力。结果表明,上述三种κ-卡拉胶邻苯二甲酰衍生物的抗氧化能力强弱顺序依次为:LC>LA>LB,这可能与衍生物的羟基含量、取代基团的性质以及取代度等因素有关。     

NF-κB介导非对称性二甲基精氨酸上调大鼠主动脉诱导型一氧化氮合酶的表达

目的探讨非对称性二甲基精氨酸(ADMA)上调大鼠主动脉诱导型一氧化氮合酶(iNOS)的表达是否是通过激活NF-κB实现的。方法 Wistar大鼠50只随机分为四组:①对照组(n=10):标准饲料喂养。②H组(n=12):高脂饲料喂养。③A+H组(n=14):予ADMA[0.2mg/kgd]灌胃,高脂饲料喂养。④P+A+H组(n=14):予吡咯烷二硫代氨基甲酸盐(pyrrolidine dithiocarbamate,PDTC)[40mg/kgd]腹腔注射、ADMA[0.2mg/kgd]灌胃、高脂饲料喂养。对照组、H组予等体积的生理盐水灌胃及腹腔注射、A+H组给予等体积的生理盐水腹腔注射。18周后麻醉大鼠、取主动脉。以实时荧光定量PCR和Westen blotting分别检测iNOS mRNA和蛋白表达,以电泳迁移率变动分析(EMSA)和增强化学发光法(ECL)检测NF-κB活性。结果①A+H组iNOS mRNA和蛋白表达量较对照组和H组增加(P<0.05),P+A+H组较A+H组iNOSmRNA和蛋白表达量降低(P<0.05)。②A+H组NF-κB活性较对照组和H组显著升高(P<0.05),P+A+H组NF-κB活性较A+H组明显降低(P<0.05)③相关分析:NF-κB活性与iNOS mRNA和蛋白表达量呈正相关(相关系数r分别为0.854、0.876,P<0.05)。结论 ADMA可能通过激活NF-κB途径上调iNOS表达,从而促进动脉粥样硬化的发生发展。     

HE4、NF-κBp65和MMP-9在卵巢上皮性肿瘤中的表达及其临床意义

目的探讨HE4、NF-κBp65以及MMP-9的表达与上皮性卵巢肿瘤临床病理生物学行为的关系以及对患者预后的影响。方法应用免疫组化对80例卵巢上皮性癌、10例交界性上皮性肿瘤及10例良性上皮性肿瘤组织进行HE4、NF-κB p65及MMP-9蛋白的检测。结果 HE4、NF-κBp65及MMP-9蛋白的阳性表达率在卵巢癌组均高于交界性及良性肿瘤组（P〈0.05）。三个指标的表达与EOC的组织学分级、腹腔脏器及淋巴结转移以及PTNM临床分期有关（P〈0.05）;在EOC中,NF-κBp65分别与HE4、MMP-9的表达呈正相关（r1=0.673,P〈0.05;r2=0.775,P〈0.05）。多因素分析,PTNM分期、MMP-9的表达是影响卵巢癌术后患者预后的独立因素（P〈0.05）;HE4阳性组与阴性组5年生存率分别为12.7%和84.0%,MMP-9阳性组与阴性组5年生存率分别为8.7%和70.6%,差异均有统计学意义（P〈0.05）。结论 NF-κBp65可能通过上调HE4、MMP-9的表达促进EOC的浸润和转移,联合检测HE4、NF-κBp65以及MMP-9的表达可能作为预测和评价患者预后的生物学指标。     

DNA聚合酶Polι的研究进展

Y家族DNA聚合酶是一种跨损伤复制酶,即能以损伤的DNA为模板进行复制。Y家族DNA聚合酶广泛分布生物界,人类细胞中Y家族DNA聚合酶至少包括Rev1、Polκ、Polι、Polη四种,Polι在以DNA为模板进行复制时错配率很高而不同于其他跨损伤DNA聚合酶,Polι是目前发现的所有DNA聚合酶中保真性最低的DNA聚合酶。很高的错配率导致很高的突变率,最后基因的突变导致癌症的发生,因此Polι在各个国家被广泛的研究,并且对Polι的各个不同的特性进行了研究,取得了一系列成果,现对Polι的研究进展予以综述,并展望了未来的研究趋势。     

二苯乙烯苷通过抑制NF-κB的激活减轻MPP＋诱导的PC12细胞凋亡

目的：探讨2,3,5,4＇-四羟基二苯乙烯-2-o-β-D-葡萄糖苷（2,3,5,4＇-tetrahydroxystibene-2-o-β-D-glucoside,TSG）对1-甲基-4-苯基吡啶离子（1-methy-4-phenylpyridinium,MPP＋）诱导PC12细胞凋亡的影响及其可能机制。方法：四甲基偶氮唑蓝（MTT）比色试验检测PC12细胞活性;Hoechst33258染色法测定细胞凋亡;Westernblotting检测NF-κB（P65）和IκBα蛋白的表达。结果：MPP＋（300μmol/L）作用于PC12细胞24h后,与正常对照组比较,细胞存活率降低（53.3±3.4%）（P〈0.01）;细胞染色质固缩,细胞核呈致密浓染。TSG（1,5,10μmol/L）预处理24h后,细胞存活率增加（60.8±1.9%）,（70.1±1.8%）（P〈0.01）,（81.2±1.9%）（P〈0.01）;细胞核凝聚明显减少,且具有量一效关系。另外,MPP＋可使PC12细胞核中NF-κB（P65）蛋白表达升高,细胞浆中IκBα蛋白表达降低;与MPP＋处理组细胞相比,TSG预处理后,PC12细胞核中高表达的NF-κB（P65）蛋白水平明显降低,细胞浆中低表达的IκBα蛋白水平升高。结论：TSG对MPP＋诱导的PC12细胞凋亡具有浓度依赖性的抑制作用,其作用机制可能与抑制NF-κB的激活有关。     

A method for fabricating uni-dsDNA microarray chip for analyzing DNA-binding proteins

This paper describes an approach for preparing unimolecular double-stranded DNA (uni-dsDNA) microarray chip. In this method, the various target oligonucleotides containing a reverse complementary sequence at 5' end were firstly annealed to a same universal oligonucleotide with amino group at 5' end and immobilized on aldehyde-derivatized glass slide. An on-chip DNA polymerization reaction was then performed to elongate the universal oligonucleotides. After a denaturation and a followed intra-strand annealing, a hairpin structure was formed at the free 3' end of the immobilized oligonucleotides. Finally, another on-chip DNA polymerization was done to synthesize the uni-dsDNA microarray. Combining with a PCR amplification of chemically synthesized target oligonucleotides, this method was much cost-effective for production of the uni-dsDNA microarray. The uni-dsDNA microarray was verified applicable for detecting the presence and monitoring the DNA-binding activity of the sequence-specific DNA-binding proteins.     

Curcumin suppresses phorbol ester-induced matrix metalloproteinase-9 expression by inhibiting the PKC to MAPK signaling pathways in human astroglioma cells

The aberrant expression of matrix metalloproteinase-9 (MMP-9) is implicated in the invasion and angiogenesis process of brain tumor. This study has investigated the effects of curcumin on MMP-9 expression in human astroglioma cell lines. Curcumin significantly inhibited the MMP-9 enzymatic activity and protein expression that was induced by PMA. The inhibitory effect of curcumin on MMP-9 expression correlates with the decreased MMP-9 mRNA level and the suppression of MMP-9 promoter activity. The curcumin-mediated inhibition of MMP-9 gene expression appears to occur via NF-kappaB and AP-1 because their DNA binding activities were suppressed by curcumin. Furthermore, curcumin strongly repressed the PMA-induced phosphorylation of ERK, JNK, and p38 MAP kinase, which were dependent on the PKC pathway. Therefore, the inhibition of MMP-9 expression by curcumin might have therapeutic potential for controlling the growth and invasiveness of brain tumor.