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891.
892.
Xu S  Xue C  Li J  Bi Y  Cao Y 《Journal of virology》2011,85(1):276-285
Viruses cause about 15% of the cancers that are still the leading causes of human mortality. The discovery of viral oncogenes has enhanced our understanding of viral oncogenesis. However, the underlying molecular mechanisms of virus-induced cancers are complex and require further investigation. The present study has attempted to investigate the effects of the microRNAs (miRNAs) encoded by Marek's disease virus 1 (MDV1), a chicken herpesvirus causing acute T-cell lymphomas and solid visceral tumors in chickens, on anti-cancer drug-induced apoptosis and identify the targets of the miRNAs. The results showed that of the total 14 miRNAs encoded by MDV1, MDV1-miR-M3 significantly promoted cell survival under treatment with cisplatin, a widely used chemotherapy drug. MDV1-miR-M3 suppressed cisplatin-induced apoptosis by directly downregulating expression at the protein but not the mRNA level of Smad2, a critical component in the transforming growth factor β signal pathway. Our data suggest that latent/oncogenic viruses may encode miRNAs to directly target cellular factors involved in antiviral processes including apoptosis, thus proactively creating a cellular environment beneficial to viral latency and oncogenesis. Furthermore, the knowledge of the apoptosis resistance conferred by viral miRNAs has great practical implications for improving the efficacy of chemotherapies for treating cancers, especially those induced by oncogenic viruses.  相似文献   
893.
Xue CB  Chai DW  Jin XJ  Bi YR  Yao XJ  Wu WS  Zhu Y 《Phytochemistry》2011,72(14-15):1804-1813
Seven oleanane-type triterpenes and two 8-O-4′-neolignans, along with five known compounds (three 28-noroleanane-type triterpenes, one sarratane triterpene, and one neolignan), were isolated from roots of Nannoglottis carpesioides. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR, HRMS, and CD. The absolute configurations of two triterpenes were determined by experimental and calculated circular dichroism (CD) and optical rotation values. Ten compounds were evaluated for their cytotoxicity against human promyelocytic leukaemia (HL-60) and human hepatoma (Hep-G2) cells using the MTT assay. The antioxidant activities of these compounds were assessed by ABTS radical-scavenging assays. Among the tested compounds, three compounds exhibited moderate radical-scavenging activity against ABTS+, with IC50 values of 22.4, 17.4, and 23.2 μM, respectively.  相似文献   
894.
江苏仑山地区上奥陶统五峰组放射虫动物群及其地质意义   总被引:1,自引:0,他引:1  
五峰组以盛产笔石动物群著称,时代为凯迪晚期(相当于英国的阿什极尔期),其中也发现了放射虫.该时期的放射虫在全球并不多见.本文首次描述江苏句容仑山地区五峰组的放射虫动物群,该动物群以不具刺的球形放射虫最为发育,并出现少量Inaniguttidae科的分子,化石保存较差,属种单调,分异度很低,这些特点与大西洋沿岸地区陆表海...  相似文献   
895.
为了构建改良型痘苗病毒安卡拉株表达系统可删除筛选标记的双表达穿梭载体,利用Cre/LoxP DNA重组系统以及本实验室表达Cre酶的BHK-21细胞系 (BHK-Cre),以大肠杆菌黄嘌呤-鸟嘌呤磷酸核糖转移酶 (Eco gpt) 为筛选标记构建可删除筛选标记的双表达穿梭载体pLR-gpt。将Eco gpt 基因以及调控其表达的启动子基因置于2个同向的LoxP位点之间,2个独立的多克隆位点位于2个LoxP位点之外,最终获得的重组病毒可以在BHK-Cre细胞系上删除筛选标记Eco gpt。为了验证系统的有效  相似文献   
896.
897.
Competing endogenous RNAs (ceRNAs) are a newly discovered class of molecular regulators involved in many diseases, especially tumors. Therefore, exploration of the potential ceRNA regulatory network regarding the occurrence and development of pancreatic cancer will provide a new theoretical basis for its diagnosis and treatment. Based on the above background, we applied a bioinformatics approach to mine the public database The Cancer Genome Atlas (TCGA) and performed a series of subsequent molecular biology assays to confirm the hypothesis that HOXA10-AS/ miR-340-3p/HTR1D axis could modulate the malignant progression of pancreatic cancer. Here, our present study demonstrated that the expression level of HTR1D, positively correlated with the level of lncRNA HOXA10-AS and negatively associated with the level of miR-340-3p, was significantly increased in pancreatic cancer cell lines (PCs) compared with that in normal HPDE6-C7 cells. Knocking down HTR1D obviously inhibited the proliferation and migration of PCs and promoted apoptosis by upregulating p-AKT. Elevated miR-340-3p blocked the progression of pancreatic cancer by downregulating HTR1D. Lessened level of lncRNA HOXA10-AS reduced the sponging of miR-340-3p, resulting in an increase of miR-340-3p and a subsequent decrease of HTR1D to ultimately suppress the malignant biological behaviors of cancer. These data illustrated that the HOXA10-AS/miR-340-3p/HTR1D ceRNA axis acted a crucial part in the malignant biological behavior of pancreatic cancer in an AKT-dependent manner.  相似文献   
898.
【目的】作为一种喜温冷敏植物,低温严重影响小桐子的生长发育、地域分布与产量。前期工作发现12 ℃低温锻炼可显著提高小桐子的抗冷性,小桐子早期光诱导蛋白(ELIP)基因是低温高响应基因。为探究JcELIP在小桐子低温响应中的作用,全面了解JcELIP的结构、调控机制、进化关系及JcELIP与miRNAs的互作关系,也为后续小桐子抗冷分子育种提供一个重要的候选基因资源。【方法】通过RT-PCR克隆了小桐子JcELIP基因并对其进行了系统的生物信息学分析,采用RT-qPCR分析了JcELIP基因在根、茎、叶中及12 ℃低温锻炼过程中的表达变化,鉴定了与JcELIP互作的miRNAs,进行了12 ℃低温锻炼过程中的共表达分析。【结果】结果显示,该基因完整的开放阅读框(ORF)为585 bp,编码194个氨基酸,蛋白大小为2.04 kD,理论等电点为9.59,属于稳定的疏水碱性蛋白,具有3个疏水跨膜螺旋;三级结构主要由ɑ-螺旋和无规则卷曲组成,具有叶绿素a/b结合位点。顺式作用元件预测显示JcELIP具有脱落酸等激素响应元件。进化分析显示,小桐子JcELIP与木薯MeELIP同源性最高。RT-qPCR分析显示,正常生长条件下小桐子JcELIP在根、茎、叶中的表达量无显著差异;12℃冷锻炼条件下JcELIP在叶中表达快速上调,48 h时其表达量达到对照组的64.8倍,表明JcELIP参与了小桐子对冷胁迫的响应与适应。基于小桐子降解组数据,鉴定到miR390-x、miR6476-x和novel-m0090-3p等8个miRNAs对JcELIP的表达具有调控作用;共表达分析结果表明在12 ℃低温锻炼过程中JcELIP的表达受miR390-x和novel-m0090-3p显著的负调控。  相似文献   
899.
Binder plays an important role in maintaining the integrity of sulfur electrode in lithium-sulfur (Li-S) battery. However, cracks are easily generated inside the electrode and compromise its performance due to the volume change of sulfur during redox reaction and continuous vibration originated from the external environments. It is a challenge yet crucial to develop tough binders with crack-insensitivity and damping performance. Herein, a polymeric binder is designed with special viscoelastic behavior by tailoring its electrolyte-philic and electrolyte-phobic domains. The loss modulus of the binder is regulated to be highly close to its storage modulus within a wide range of frequency, generating an ultra-high loss factor and equilibrium of viscosity-elasticity. Based on such rheological behavior, the binder holds 1) high damping ability across a wide frequency to suppress crack generation, 2) high toughness with crack blunting behavior to resist crack propagation, 3) efficient healing capability to repair the cracks. Besides, the pendant zwitterionic groups can immobilize the lithium polysulfides and promote ion transfer. Benefiting from these advantages, the obtained Li-S battery delivers high specific capacity with considerable capacity retention after long-term cycling. The viscoelastic design and crack management strategy illustrated here would provide new insights into the binder design.  相似文献   
900.
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