Aberrant expression of oncogenic and tumor-suppressive microRNAs in cervical cancer is required for cancer cell growth

MicroRNAs (miRNAs) play important roles in cancer development. By cloning and sequencing of a HPV16(+) CaSki cell small RNA library, we isolated 174 miRNAs (including the novel miR-193c) which could be grouped into 46 different miRNA species, with miR-21, miR-24, miR-27a, and miR-205 being most abundant. We chose for further study 10 miRNAs according to their cloning frequency and associated their levels in 10 cervical cancer- or cervical intraepithelial neoplasia-derived cell lines. No correlation was observed between their expression with the presence or absence of an integrated or episomal HPV genome. All cell lines examined contained no detectable miR-143 and miR-145. HPV-infected cell lines expressed a different set of miRNAs when grown in organotypic raft cultured as compared to monolayer cell culture, including expression of miR-143 and miR-145. This suggests a correlation between miRNA expression and tissue differentiation. Using miRNA array analyses for age-matched normal cervix and cervical cancer tissues, in combination with northern blot verification, we identified significantly deregulated miRNAs in cervical cancer tissues, with miR-126, miR-143, and miR-145 downregulation and miR-15b, miR-16, miR-146a, and miR-155 upregulation. Functional studies showed that both miR-143 and miR-145 are suppressive to cell growth. When introduced into cell lines, miR-146a was found to promote cell proliferation. Collectively, our data indicate that downregulation of miR-143 and miR-145 and upregulation of miR-146a play a role in cervical carcinogenesis.     

RNA-binding protein HuR interacts with thrombomodulin 5'untranslated region and represses internal ribosome entry site-mediated translation under IL-1 beta treatment

Reduction in host-activated protein C levels and resultant microvascular thrombosis highlight the important functional role of protein C anticoagulant system in the pathogenesis of sepsis and septic shock. Thrombomodulin (TM) is a critical factor to activate protein C in mediating the anticoagulation and anti-inflammation effects. However, TM protein content is decreased in inflammation and sepsis, and the mechanism is still not well defined. In this report, we identified that the TM 5′ untranslated region (UTR) bearing the internal ribosome entry site (IRES) element controls TM protein expression. Using RNA probe pulldown assay, HuR was demonstrated to interact with the TM 5′UTR. Overexpression of HuR protein inhibited the activity of TM IRES, whereas on the other hand, reducing the HuR protein level reversed this effect. When cells were treated with IL-1β, the IRES activity was suppressed and accompanied by an increased interaction between HuR and TM 5′UTR. In the animal model of sepsis, we found the TM protein expression level to be decreased while concurrently observing the increased interaction between HuR and TM mRNA in liver tissue. In summary, HuR plays an important role in suppression of TM protein synthesis in IL-1β treatment and sepsis.     

云南南亚热带地区冬玉米种植的生态生理学研究

１９９６－１９９８年,在蒙自县草坝进行了玉米冬播栽培的试验和大面积种植,并连年获得高产。主要是：１．冬播玉米有明显较长的生育期。２．冬玉米的叶片发展和光热资源有较好的匹配。构成了冬播玉米高产的基础。３灌浆中期全天平均光通量密度为１３９１．８μE.m^-2.s^-1,植株实际截获８７．６％的总通量。底层相对较高的透光延缓了叶片的衰老。为灌浆期总干物质生产提供了较好的条件。４,冬播玉米开发后的干物质生产量占总干物质量的７２．１％,有利于籽粒生产。５冬播玉米灌浆期生长的同化物最终有１２．７８％存留于营养体中,表明库容是生产力的限制因数,扩大库容可使其籽粒产量进一步提高。     

木兰属叶片的比较解剖学研究

对木兰属（Magnolia)12种、1亚种植物的叶片进行了比较解剖学研究。结果表明：（1）Nootboom系统的云南木兰（M.yunnanensis)和乐东木兰（M.lotungensis)的叶肉中含有大量的单宁,与木兰属其他植物叶片的解剖结构有较大区别,支持刘玉壶系统^[2]拟单性木兰属（Parakmeria)的建立;（2）凹叶厚朴（M.officinalis ssp.biloba)为厚朴（M.officinalis)的亚种,二者下表皮均被表皮毛,但表皮毛的细胞个数明显不同,因而很易区分;（3）木兰属植物的叶片在叶片厚度、栅栏组织和海绵组织厚度的比例、表皮毛、油细胞大小及其分布密度密度等方面在种间具有一定差别。     

细叶楠种子休眠与萌发对低温层积的生理响应

细叶楠(Phoebe hui Cheng ex Yang)是我国特有的珍贵树种,种子具有生理休眠特性。本文以细叶楠种子为实验材料,研究不同低温层积处理时间(0、20、40、60 d)对细叶楠种子发芽率、营养物质(淀粉、可溶性糖、可溶性蛋白)、过氧化物酶(POD)以及内源激素脱落酸(ABA)、赤霉素(GA₃)、生长素(IAA)、玉米素核苷(ZR)的影响,分析细叶楠种子萌发与其生理指标的相关性。结果显示：(1)低温层积可以有效打破细叶楠种子的休眠,且处理60 d效果最佳。(2)在低温层积过程,细叶楠种子萌发时间缩短,发芽率提高;种子内淀粉含量降低,可溶性糖和可溶性蛋白含量升高;POD活性上升;ABA含量下降,GA₃、IAA含量增加,而ZR含量先上升后下降。(3)细叶楠种子休眠的解除与萌发与其体内营养物质含量、POD活性以及内源激素含量的变化密切相关。     

大鼠肢体缺血/再灌注后的心肌损伤和NO的保护效应

目的:探讨大鼠肢体缺血/再灌注(LI/R)后心肌的损伤性变化及NO的保护效应。方法:制备LI/R动物模型,将Wistar大鼠随机分为4组(n=10):C(control)组、I/R组、L-Arg组和L-NAME组。用生物化学方法测定大鼠血浆CK、CK-MB及NO水平,测定心肌组织XOD、SOD、MDA含量。用BL-420生物机能实验系统监测大鼠MAP、LVSP、±dp/dtmax等。结果:LI/R后,血浆CK、CK-MB水平均明显升高(P<0.01);心肌组织SOD活性降低而MDA、XOD含量增加(P<0.01或P<0.05);MAP、LVSP、dp/dtmax、-dp/dtmax均降低(P<0.01或P<0.05);血浆NO水平在L-Arg组明显升高(P<0.01),在L-NAME组显著降低(P<0.05)。结论:大鼠LI/R可引起心肌损伤,机体的氧化应激状态可能是其发生机制之一;提高体内NO水平可在一定程度上减轻LI/R后心肌损伤的程度。     

基因治疗糖尿病的研究进展

随着基因转移技术的进步,引导了在分子水平研究替代正常胰岛素释放功能的方法,葡萄糖刺激胰岛素分泌的β细胞系和非β细胞系的构建已有一定的进步,胰岛素基因直接转染给动物体内可以控制血糖.因此,细胞工程和基因疗法必将会为糖尿病治疗开拓广阔的前景.     

喀斯特地区不同类型兰科植物的叶片性状

叶片性状能够反映植物对环境的适应.认识喀斯特地区兰科植物的叶片性状及其适应意义对其科学合理的保育具有重要参考价值.本文于干季与雨季研究了广西雅长兰科植物自然保护区内落叶、常绿地生、常绿石附生三种类型共19种野生兰科植物的叶片性状及其相互关系,并比较了不同类型兰科植物之间的差异.其中18种兰科植物为C3植物,仅棒叶鸢尾兰(Oberonia myosurus)为CAM植物.相比于落叶兰,常绿兰具有较高的比叶重( LMA)和叶片碳氮比(C/N),但其叶片氮、磷含量较低.在常绿兰科植物中,石附生兰的叶片Ca含量与δ13C高于地生兰.石附生兰的叶片磷含量在雨季要高于干季,而地生兰的叶片δ13C在于季要高于雨季.该地区常绿兰科植物的N/P值＞16,表明其可能受到磷的限制.