Effect of 24-epibrassinolide on growth,yield, antioxidant system and cadmium content of bean (Phaseolus vulgaris L.) plants under salinity and cadmium stress

The plants of Phaseolus vulgaris L. were grown in the presence of NaCl and/or CdCl₂ and were sprayed with 5 μM of 24-epibrassinolide (EBL) at 15 days after transplanting (DAT) and were sampled at 30 DAT and at the end of experiment. The plants exposed to NaCl and/or CdCl₂ exhibited a significant decline in growth, the level of pigment parameters, green pod yield and pod protein. However, the follow up treatment with EBL detoxified the stress generated by NaCl and/or CdCl₂ and significantly improved the above parameters. The NaCl and/or CdCl₂ increased electrolyte leakage, lipid peroxidation and plant Cd²⁺ content, and decreased the membrane stability index (MSI) and relative water content. However, the EBL treatment in absence of the stress improved the MSI and relative water content and minimized plant Cd²⁺ content but could not influence electrolyte leakage and lipid peroxidation. The antioxidative enzymes and the level of proline exhibited a significant increase in response to EBL as well as to NaCl and/or CdCl₂ stress.     

水葫芦生防真菌Cercosporasp.FJ24的分离、鉴定及其分子生物学研究

从福建省得到被致病菌强烈感染的水葫芦植株,从中分离到致病菌菌株FJ24。形态学鉴定表明,该致病菌属于尾孢属。对该菌株的ITS区、EF-1、β-Tub、His-H3基因进行PCR扩增,测序结果显示其与目前已经分离、发现的多种尾孢属水葫芦致病菌存在着99%以上的序列相似性,可以认为其属于半知菌类（无性类）、丝孢纲、丝孢目、淡丛梗孢科、尾孢属的Cercospora piaropi。     

Effects of 24-Epibrassinolide on Antioxidant System in Cucumber Seedling Roots Under Hypoxia Stress

This article aims to study the effects of exogenous 24-epibrassinolide (EBR) on the changes in ROS, activities of antioxidative enzymes and antioxidants in cucumber (Cucumis sativus L.) seedling roots under hypoxia stress. Seedlings of a hypoxianormoxic or hypoxic nutrient solutions that were added or not added with 10-3 mg L-1 EBR. Under hypoxia stress, the ROS levels and the lipid peroxidation were significantly increased in the roots upon exposure to hypoxia stress, which were inhibited by EBR application. The EBR treatment significantly increased the seedlings growth and SOD, APX, GR activities, and contents of AsA and GSH under hypoxia stress. From the results obtained in this study, it can be concluded that oxidative damage on seedling roots by hypoxia stress can be considerably alleviated and the tolerance of plants was elevated.     

MicroRNA-24 regulates apoptosis of cardiomyocytes after myocardial infarction

AIM：To evaluate the expression of miR-24 in infarcted myocardial tissues and to investigate the function of miR-24 during cardiomyocyte apoptosis in vitro and in vivo. METHODS：The mouse model of myocardial infarcton (MI) was established. The expression of miR-24 in the sections of infarcted myocardial tissues was measured by qRT-PCR. The expression of miR-24 was modified by transfecting oligonucleotide mimic and inhibitor of miR-24 into cardiomyocytes, or injecting lentiviral vectors intramyocardially. The apoptosis of cardiomyocytes was detected by Caspase-Glo 3/7 Assay System. The heart functions were determined by echocardiography and the scar size in MI model was observed with Masson trichrome staining. The apoptosis of infarcted myocardial tissues was detected by TUNEL method. Microarray and bioinformatic analysis were also used to predict the targets of miR-24. RESULTS：The expression of miR-24 in the infarct and border areas was down-regulated after MI. Overexpression of miR-24 in cardiomyocytes reduced the apoptosis induced by hypoxia. miR-24 transfection resulted in reduction of the scar size, and improved left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) of the mice in treatment group after 2 weeks. Furthermore, miR-24 reduced cell apoptosis in the infarct region. BCL2L11, ANK3 and SGPL1 may be the targets of miR-24 during the process of anti-apoptosis. CONCLUSION：miR-24 is down-regulated in the infarcted myocardial tissues. In vitro, miR-24 reduces apoptosis of cardiomyocytes induced by hypoxia. In vivo, miR-24 attenuates cell apoptosis in the infarct and border areas of the heart 2 weeks after MI, and ultimately improves heart functions.     

一种基于模板DNA的PCR扩增难易预测方法

借助赋予四种碱基A,G,C,T四个三维空间中的点(0,0,1),(0,1,0),(-1,-1,0),(1,0,0),将一条DNA序列转化为一个二十四维向量。在此基础上利用Fisher线性判别法对人类基因组中189条基因片段进行PCR扩增难易预测,识别率达到了90%。     

EBR对NaCl胁迫下苜蓿属植物离子吸收和分配的影响

为探究苜蓿属植物的抗盐机理及外源油菜素内酯(EBR)对苜蓿属植物抗盐性的影响,选取蒺藜苜蓿、紫花苜蓿和金花菜3种苜蓿属植物为实验材料,研究NaCl胁迫及NaCl胁迫下喷施EBR对苜蓿属植物生长,体内无机离子吸收、分配及运输的影响。结果表明:1)NaCl胁迫会抑制苜蓿属植物的生长,影响植物体内K⁺、Ca²⁺、Mg²⁺离子的分配和运输。2)EBR能有效缓解NaCl胁迫对植物生长的抑制作用,维持植物体内的离子平衡,从而提高植物的耐盐性。3)紫花苜蓿耐盐性较强,蒺藜苜蓿耐盐性较弱。4)在盐胁迫条件下,紫花苜蓿根部抑制对Na⁺的吸收,减少离子毒害作用;蒺藜苜蓿将根中的Na⁺向茎和叶中运输,通过叶片的脱落,维持生长点的正常生长。     

紫花苜蓿MsBBX24基因的克隆及耐盐性分析

盐胁迫是影响植物生长发育的主要非生物胁迫因子之一，BBX家族转录因子在植物色素积累、光形态发生、种子生长发育以及逆境适应等方面具有重要的调节作用。为明确紫花苜蓿BBX基因的功能，本研究使用Primer Premier 5软件根据NCBI数据库MsBBX24基因的序列设计特异性引物，以紫花苜蓿的cDNA为模板克隆MsBBX24基因。利用生物信息学软件对基因序列和结构进行分析，并与其他植物的BBX24进行比对和进化树构建，分析它们之间的进化关系。采用实时荧光定量PCR(qRT-PCR)分析MsBBX24基因的表达模式。利用DNA的酶切与连接方法构建MsBBX24过表达载体，采用农杆菌介导法将其转入野生型拟南芥，通过除草剂Basta筛选，以半定量RT-PCR鉴定获得阳性转基因植株。通过对野生型和MsBBX24转基因拟南芥植株的表型观察和生理指标测定分析它们的耐盐性。研究结果表明，MsBBX24基因编码区序列长723 bp，编码240个氨基酸，分子量为30.58 kDa，等电点为7.74,MsBBX24与鹰嘴豆和蒺藜苜蓿的BBX24具有较高的同源性。qRT-PCR检测结果表明，MsBBX24基...     

高温条件下miRNA-24对奶牛乳腺上皮细胞增殖与凋亡的影响

【目的】MicroRNA(miRNA)是一类长度约21-23个核苷酸的非编码小RNA分子,本研究旨在分析高温条件下miRNA-24对乳腺上皮细胞生长、凋亡的作用及其初步机制。【方法】体外培养奶牛乳腺上皮细胞,高温(41℃)处理所培养的细胞;应用miRNA基因沉默技术,抑制高温处理过的乳腺上皮细胞中miRNA-24的表达;采用细胞计数法分析细胞增殖情况;Hoechst33342/PI荧光染色、流式细胞术检测miRNA-24对乳腺上皮细胞凋亡的作用,Western blot检测凋亡相关因子表达变化。【结果】抑制miRNA-24的表达,高温条件下的乳腺上皮细胞增殖能力显著增强(P0.05),凋亡细胞数显著减少(P0.05),促凋亡因子caspases-8和caspases-3表达量下调。【结论】内源性miRNA-24对乳腺组织发育具有重要的调控作用,抑制miRNA-24的表达可以缓解高温诱导下奶牛乳腺上皮细胞凋亡发生率、促进细胞的生长发育。     

向日葵叶抗氧化成分24-亚甲基环木菠萝烷醇的分离提取

通过对向日葵叶乙酸乙酯、0.5%稀盐酸混合液提取物的氯仿萃取部分的分离纯化,得到一个化合物。经MS鉴定其分子量为440,为24-亚甲基环木菠萝烷醇,且为首次从该植物中分离得到。用普鲁士蓝法以茶多酚为对照研究该化合物的抗氧化活性。结果表明,24-亚甲基环木菠萝烷醇具有抗氧化活性,但比同浓度茶多酚的抗氧化活性要弱。     

添加乳酸菌对不同生长期全株早籼饲料稻青贮品质的影响

本研究分别选用处于抽穗期、乳熟期、蜡熟期和黄熟期的全株湘早籼24饲料稻做为青贮原料,以研究不同生长期和添加乳酸菌对全株湘早籼24饲料稻青贮料感官指标、营养成分和乳酸菌含量的影响。试验采用2×4两因子试验设计,每个生长期分别设对照组和乳酸菌组,乳酸菌组添加0.01g/kg(以鲜重计)的乳酸菌制剂,共8个处理,每个处理3个区组,每个区组6个青贮罐,共144个青贮罐。试验结果表明:(1)随着水稻生长期的延长,水稻的DM、OM含量极显著增加(P0.01);CP含量在前三个生长期逐渐降低;前两个生长期的WSC含量和ADF含量极显著高于后两个生长期(P0.01)。(2)感官评定结果以第三个生长期最好,添加乳酸菌有改善青贮料色泽和气味的趋势。青贮料的pH值以抽穗期的最低,黄熟期的最高;随着生长期的延长,青贮料的DM含量极显著上升(P0.01),干物质回收率呈下降趋势(P0.05);氨态氮和氨态氮/总氮比值在前三个生长期呈上升的趋势。(3)添加乳酸菌明显提高了各生长期青贮料的pH值,极显著提高了各生长期青贮料的乳酸菌含量(P0.01),同时添加乳酸菌提高了青贮料中DM、OM含量(P0.05或P0.01)和干物质回收率(P0.01)。