miR-140-5p对前脂肪细胞3T3-L1成脂分化的机制研究

【目的】研究miR-140-5p在前脂肪细胞(3T3-L1)成脂分化过程中的功能及其作用机制。【方法】待3T3-L1细胞汇合度达100%时诱导其成脂分化,收集分化第―1(诱导分化前1 d)、0、1、2、3、5、7天的细胞,用实时荧光定量PCR检测miR-140-5p相对表达量;将miR-140-5p mimics、NC转染3T3-L1细胞并诱导成脂分化,油红O染色观察脂滴形成情况,实时荧光定量PCR检测成脂标志基因CAAT增强子结合蛋白β(C/EBPβ)、CAAT增强子结合蛋白δ(C/EBPδ)与过氧化物酶体增殖物激活受体γ(PPARγ)相对表达量;利用miRandn和TargetScan在线网站预测miR-140-5p的靶基因;通过对比序列差异分析P300/CBP相关因子(PCAF)的3′-UTR序列中与miR-140-5p的结合位点序列在小鼠、人等不同物种间的序列保守性。将miR-140-5p mimics、inhibitor、NC转染3T3-L1细胞并诱导成脂分化,实时荧光定量PCR检测miR-140-5p、PCAF相对表达量,Western blotting检测PCAF蛋白水平...     

Effects of dietary alpha‐linolenic acids on growth performance,lipid metabolism and antioxidant responses of juvenile Russian sturgeon Acipenser gueldenstaedtii

Five isonitrogenous diets were formulated with graded alpha‐linolenic acid (LNA) levels (0, 5, 10, 15 and 20 g/kg) to investigate LNA requirement of juvenile Russian sturgeon Acipenser gueldenstaedtii. Weight gain and specific growth rate of fish fed LNA5 and LNA10 were significantly higher than those in other groups, while the feed conversion ratio of these two groups was lower than others. Dietary LNA increased n‐3 polyunsaturated fatty acid and n‐3/n‐6 ratio, but decreased saturated fatty acid contents in the liver. DHA in the fish tissue also increased with the increased dietary LNA. The superoxide dismutase activity was highest in fish fed LNA5. Fish fed LNA10 showed the highest catalase activity and the highest malondialdehyde content. A 459‐bp fragment of Δ6 fatty acid desaturase and a 474‐bp fragment of elongases of very long chain fatty acids 5 were cloned and analysed. The expressions of these two genes were higher in fish fed LNA15 and LNA20. The highest hepatic lipase activity occurred in fish fed LNA 20, and the malate dehydrogenase activity peaked in the LNA5 group. Based on SGR and FCR, the range of optimum dietary LNA concentration for juvenile Russian sturgeon is recommended at 6.85–10.69 g/kg.     

红花miR397a基因表达及对靶基因LAC2的调控作用

【目的】研究红花miR397a前体基因及成熟基因在红花不同组织中的表达水平,并对miR397a基因序列、靶基因及基因功能进行分析,为深入研究红花抗逆机制提供参考。【方法】提取红花籽粒、花瓣、茎、根、叶片等5个组织材料的总RNA,使用荧光定量PCR鉴定miR397a在不同组织中的表达水平;利用生物信息学方法分析红花miR397a基因序列,用原生质体转化方法验证红花miR397a调控的靶基因LAC2,并利用转基因拟南芥表型研究miR397a基因的功能。【结果】miR397a前体基因和成熟基因均能在红花不同组织中表达,且均以叶片组织中的表达量最高,分别是籽粒组织的2.5与1.9倍,差异达极显著水平;miR397a序列在不同物种间高度保守,序列中仅存在1~2个碱基的错配或缺失;miR397a对LAC2基因有调控作用,miR397a的过表达可引起LAC2表达水平降低,红花miR397a表达引起植物对NaCl的敏感性增加。【结论】红花miR397a在叶片组织中的表达量最高,基因序列保守,且红花miR397a表达可增强植物对NaCl的敏感性。     

冬小麦miR398前体的克隆及其在低温条件下对靶基因CSD1表达的调控

miR398是受逆境胁迫负调控的miRNA,其靶基因CSD编码超氧化物歧化酶(SOD),使植物抵御活性氧(ROS)的毒害。为进一步了解低温胁迫下miR398的调控机制,从东农冬麦1号中克隆小麦miR398前体,构建过表达载体并转化拟南芥,用Real-time PCR检测T0代植株中小麦miR398及其靶基因CSD1在低温胁迫下的表达量。结果表明,随着低温胁迫时间的延长,miR398表达下调、CSD1基因表达上调,认为小麦miR398能响应低温胁迫、负调控CSD1基因表达,间接提高了拟南芥的抗寒性。     

木署中miR393的RT-PCR鉴定及前体的克隆与结构分析

研究木薯中表达的miRNA对深入探明木薯生长发育的调控机制具有十分重要的意义.通过RT-PCR证实木薯中有miR393的表达.采用比较基因组学的方法,从木薯基因组DNA中克隆到miR393的前体,对该miRNA前体的二级结构及与其它物种序列的同源性进行分析,结果表明,miR393前体序列在不同物种间保守性不高,但成熟的...     

Effects of dietary corn oil and vitamin E supplementation on fatty acid profiles and expression of acetyl CoA carboxylase and stearoyl‐CoA desaturase gene in Hu sheep

This study was conducted to assess the effects of dietary corn oil and vitamin E supplementation on fatty acid (FA) profiles and abundances of acetyl‐CoA carboxylase (ACC) and Δ⁹ stearoyl‐CoA desaturase (SCD) mRNA of Hu sheep. Animals were allocated to three dietary treatments: basal and supplemented with 3% corn oil (CNO), or CNO plus 500 mg/kg vitamin E (COE). The experiment lasted for 10 weeks. No differences were observed in growth performance and carcass qualities among the three treatments (P > 0.05). Feeding CNO and COE diets increased polyunsaturated FAs including cis 9 trans 11 conjugated linoleic acid, and decreased saturated FA in longissimus muscle (P < 0.05). The mRNA abundances of ACC and SCD as detected by real‐time PCR were reduced (P < 0.05) in liver and subcutaneous fat by supplementary oil, while the SCD mRNA level in longissimus muscle was also reduced (P < 0.05). Inclusion of vitamin E did not have further effects on mRNA abundances of these two enzymes. It is suggested that dietary corn oil supplementation may reduce FA biosynthesis and influence FA profiles in Hu sheep through decreased expression of both ACC and SCD genes.     

植物miR398家族的分子特征与进化分析

miR398家族是植物界中一类保守的miRNA家族,本文旨在探究植物miR398家族成员的分子特征,阐释其系统进化规律。以数据库公布的植物miR398成熟体、前体及靶标序列为供试数据,用统计学和生物信息学法分析其分子特征与进化规律。miR398家族成员在34个植物物种中分布广泛,其成熟体长度、核苷酸种类、前体茎环结构及对靶基因抑制类型均符合典型的植物miRNA分子特征。不同植物间miR398成熟体保守性高于前体,前体茎部保守性高于环部。同一物种间的miR398家族成员具有不同的进化速率,少数物种间的miR398家族具有协同进化特征。靶基因功能预测结果显示,miR398家族成员多以切割抑制的方式参与植物的逆境胁迫响应。植物miR398家族兼具保守性与多态性特征,不同植物间的miR398家族成员具有多样的进化模式。研究结果为miR398介导的植物逆境胁迫响应机制探究奠定理论基础。     

miR1320表达水平与水稻白叶枯病抗性的关联性分析

水稻白叶枯病是由稻黄单胞菌水稻致病变种Xanthomonas oryzae pv. oryzae(Xoo)引起的一种细菌性病害,严重影响水稻的产量和品质。miR1320是水稻与Xoo互作中重要的调控因子。本研究在接种Xoo后的0、12、24 h分别检测了10个粳稻和8个籼稻品种中miR1320的积累和4个防卫基因的转录水平,测量了各品种叶片上的病斑长度,分析了miR1320的积累和防卫基因的表达与水稻白叶枯病抗性之间的相关性。结果表明:接种Xoo后,miR1320的表达模式在不同品种中有所不同;籼稻和粳稻对白叶枯病的抗性分别与接种后24 h和12 h时miR1320的表达量呈紧密负相关;且相对于防卫基因,miR1320更能反映品种间的抗病性。因此,miR1320可应用于评估水稻品种对白叶枯病的抗性,辅助水稻抗病种质的鉴定。     

枯草芽胞杆菌PTS-394的GFP标记及其定殖能力

为探明枯草芽胞杆菌PTS-394在番茄根围的定殖能力,采用电转化法获得绿色荧光蛋白（green fluorescent protein,GFP）标记菌株PTS-GFP,构建其生长曲线,采用对峙生长法评价其室内抑菌活性,并应用抗生素平板回收结合激光扫描共聚焦显微镜观察标记菌株在番茄根围的定殖数量。结果显示：与原始菌株PTS-394相比,标记菌株PTS-GFP的生长、对青枯病菌和4种病原真菌的室内抑菌能力无明显差异。标记菌株PTS-GFP和青枯病菌菌液单独或混合处理番茄苗,灌根当天标记菌株初始菌量接近10⁸ CFU/g,处理3 d后种群数量迅速下降,约10⁶ CFU/g,随后缓慢下降,处理10 d后种群数量约10⁴ CFU/g,处理30 d后,标记菌株仍然能被检测到,约20 CFU/g。表明枯草芽胞杆菌PTS-394在番茄根际土壤中具有一定的定殖能力。