IBA处理对杂交榛根蘖育苗生根指标及相关氧化酶活性的影响

以"龙榛1号"当年萌生条为试材,研究了不同IBA浓度处理(500、750、1 000、1 250mg·L^-1)对平欧杂交榛根蘖育苗生根的影响,分析了根蘖育苗生根过程中过氧化物酶(POD)、多酚氧化酶(PPO)活性的变化,并对外源激素处理与相关氧化酶活性与生根的关系进行了相关性分析,以期探讨其生根机理。结果表明:IBA浓度处理能显著地提高生根率,以1 000mg·L^-1的生根效果最佳,生根率和不定根质量均显著高于其它处理。生根过程中,POD和PPO活性呈先上升后下降趋势,POD活性在育苗后20d出现峰值;PPO活性在40d时达到峰值。生根率与POD、PPO活性呈极显著正相关。说明适宜浓度IBA能增加生根过程POD、PPO活性,从而提高生根率。     

红茶提取物对高尿酸血症小鼠血尿酸的影响

研究红茶提取物对高尿酸血症小鼠血尿酸的影响。将36只雄性KM小鼠随机分为空白组、模型组、红茶提取物低、中、高剂量组及别嘌呤醇组。空白组和给茶组连续1周分别灌胃生理盐水和红茶提取物,给茶组第7天造模后1 h给茶;模型组在第7天腹腔注射氧嗪酸钾并灌胃酵母膏造模。测定结果显示:与模型组相比,各给茶组血尿酸(UA)水平均降低;与模型组相比,给茶组血尿素氮(BUN)水平均降低,其中、高剂量给茶组BUN水平显著降低(P0.05),高剂量组差异极显著(P0.01);各给茶组血肌酐(Cr)值与模型组相比极显著下降(P0.001)。高剂量组黄嘌呤氧化酶(XOD)活性较模型组显著降低(P0.05),低、中剂量组有一定的抑制作用,但无显著差异。研究表明,红茶提取物对氧嗪酸钾和酵母膏导致的小鼠高尿酸血症有明显的改善作用。     

5种蔷薇科树种多酚氧化酶比较基因组学分析

蔷薇科植物中有多种具有重要价值的水果,如苹果、梨、桃、草莓和黑树莓等。这些水果普遍容易发生由多酚氧化酶(PPO)介导的酶促褐变而导致重大经济损失,从全基因组角度分析比较PPO基因家族,有助于加深对PPO基因家族和功能的认识。采用比较基因组学的方法,对这5种植物的PPO基因家族进行了基因鉴定、染色体定位、编码蛋白的亚细胞定位、内含子统计分析、基因系统进化、基因倍增与丢失等特征分析。从这5种植物中,共计鉴定出了42个PPO基因,其中6个基因被认定是假基因;绝大多数基因编码的蛋白定位于叶绿体,2个定位于线粒体,3个是分泌型蛋白;PPO基因在染色体上有串联重复和散布两种形式;9个基因具有内含子,聚类结果显示可以将它们分为6个类型,每个基因类型在进化过程中都发生过基因倍增和丢失;同型基因内含子的位置和大小具有相似性。这些结果揭示蔷薇科植物PPO基因内含子是伴随着基因倍增产生的,基因倍增也是推动PPO基因多样化的重要动力,PPO基因倍增和丢失差异导致PPO基因数量在不同物种之间产生差异。     

Chemical Constituents of Lagenaria siceraria Mesocarp and Its Xanthine Oxidase and Alpha-Amylase Inhibitory Activities

The present study was conducted to identify natural products in the bioactive fractions of Lagenaria siceraria mesocarp. Column chromatography and gas chromatography-mass spectrometry (GC-MS) was used for separation and identification of phytochemicals. Methanolic extract and its fractions displayed alpha-amylase and xanthine oxidase inhibitory activities comparable to standard drugs. GC-MS analysis of the fractions and column eluates revealed the presence of a variety of chemical compounds, including 4-(methoxymethyl)phenol, 2,2?-methylenebis{6(1,1-dimethylethyl)-4-ethyl}phenol, methyl 2-hydroxy-3-phenylpropanoate, oxacyclododecane-2,8-dione, N-(2-(4-hydroxyphenyl)ethyl] acetamide, 2,3-Epoxycarane, 4-(propan-2-yl)benzaldehyde, octadec-1-ene, 4a-methyl-1-methylidene-1,2,3,4,4a,9,10,10a-octahydrophenanthrene, 2,6-di(propan-2-yl)naphthalene, methyl 3-(4-hydroxy-3,5-dimethylphenyl)propanoate, 4,8a-dimethyl-6-(prop-1-en-2-yl)-3,5,6,7,8,8a-hexahydronaphthalen-2(1H)-one 1,3-dihydro-2-benzofuran, methyl N-hydroxybenzenecarboximidoate, linoleic acid, and palmitic acid. Many of these compounds are being reported for the first time from this plant, the presence of which may explain, at least partly, its medicinal efficacy. The fruit possesses significant anti-enzymatic properties against alpha-amylase and xanthine oxidase, and the most active compounds of mesocarp of the fruit appear in ethyl acetate fraction of its methanolic extract.     

Effect of hypercapnia on lysyl oxidase-dependent collagen cross-linking and hypoxia-induced pulmonary hypertension in rat

AIM: To investigate the effect of hypercapnia on hypoxia-induced pulmonary hypertension and the changes of lysyl oxidase (LOX) and extracellular matrix collagen cross-links in the rat. METHODS: Sprague-Dawley rats were randomly divided into 4 groups:normoxia group, hypoxia group, hypercapnia group and hypoxia+hypercapnia group. LOX activity was detected by fluorescence spectrophotometry. LOX protein expression was detected by immunohistochemistry and Western blot. The mRNA expression of LOX in the pulmonary artery was detected by real-time PCR. RESULTS: The levels of mean pulmonary artery pressure (mPAP), RV/(LV+S) and WA/TA in hypoxia group were significantly higher than those in normoxia group (P<0.01). Moreover, the levels of mPAP and RV/(LV+S) in hypoxia+hypercapnia group were significantly lower than those in hypoxia group (P<0.01). However, no significant difference of mPAP and RV/(LV+S) between hypercapnia group and normoxia group was observed. In hypoxia group, the collagen cross-links in the lung tissue was significantly higher than that in normoxia group and hypercapnia group (P<0.01). Importantly, collagen cross-links in the lung tissue of hypoxia+hypercapnia group was significantly lower than that in hypoxia group (P<0.01). There was no significant difference in collagen cross-links between hypercapnia group and normoxia group. The expression of LOX at mRNA and protein levels and its activity in the pulmonary arteries of hypoxia group were significantly increased as compared with normoxia group (P<0.01). Furthermore, the expression of LOX at mRNA and protein levels and its activity in the pulmonary arteries in hypoxia+hypercapnia group were lower than those in hypoxia group (P<0.01). CONCLUSION: Hypoxia not only up-regulates LOX but also promotes collagen cross-linking in the rat lung, which contributes to the development of pulmonary hypertension. Hypercapnia inhibits hypoxia-induced LOX expression and collagen cross-linking, therefore impairing the progress in hypoxia-induced pulmonary hypertension.     

北青龙衣褐变机制的研究

北青龙衣在由鲜品到干品的贮藏期间会出现失水、颜色变深等褐变现象。研究该褐变过程发生的机制,为控制褐变、提高药材的稳定性提供试验依据。采用北青龙衣鲜果果皮,4℃低温贮藏,研究其褐变度(browning degree,BD)、多酚氧化酶(polyphenol oxidase,PPO)、苯丙氨酸解氨酶(phenylalanine ammonialyase,PAL)、过氧化物酶(peroxidase,POD)活性变化、丙二醛(malondialdehyde,MDA)、总多酚(total polyphenols,TP)、还原糖含量及维生素C(Vitamin C,VC)含量变化。试验数据显示果皮颜色变深、TP含量下降、PPO活性降低、PAL活性上升、SOD和POD活性先上升后下降、MDA含量升高、还原糖和VC含量下降。BD与PPO、SOD、POD活性和TP含量呈显著负相关,与PAL活性呈显著正相关,与VC和还原糖无显著相关性。北青龙衣贮藏过程中发生了酶促褐变和非酶褐变,且以酶促褐变为主,PPO在酶促褐变中可能起主要作用。     

无核白葡萄多酚氧化酶基因的克隆与序列分析

为获得无核白葡萄中多酚氧化酶(PPO)的基因序列,以无核白葡萄果实为试材,进行基因同源克隆,得到多酚氧化酶基因CDS全长序列,其完整的编码框为1 824 bp,编码607个氨基酸(GenBank登陆号为KP271928);系统进化分析可知,其与葡萄科植物PPO基因同源性最高;生物信息学方法发现该蛋白分子量为67 392.44 Da,等电点为6.42,具典型的酪氨酸家族结构域,无信号肽结构,但有一个跨膜结构域,为亲水性蛋白;二级结构预测发现,PPO具有CuA与CuB两个结合区,分别嵌入蛋白活性腔中。该研究为进一步从分子水平探讨多酚氧化酶与褐变的关系奠定理论基础。     

饮用天然高钼水诱发的钼中毒耕牛主要生物酶测定

本研究对高钼饮水诱导钼中毒的耕牛及对照牛的血浆及组织（肝脏、肺脏、肾脏、脾脏、心脏、肌肉）中超氧化物歧化酶（ＳＯＤ）、黄嘌呤氧化酶（ＸＯＤ）及谷胱甘肽过氧化物酶（ＧＳＨ－ＰＸ）等３种生物酶活性进行了对比分析测定。结果表明,血浆和组织中ＳＯＤ、ＸＯＤ及ＧＳＨ－ＰＸ均随着钼中毒的加重其活性显著下降。这３种生物酶是钼中毒比较灵敏且相关较大的生化指标,对钼中毒具有一定诊断价值;测定ＳＯＤ。ＸＯＤ、ＧＳＨ－ＰＸ可作为钼中毒监测的重要手段。     

Continuous Spectrophotometric Assay and Properties of Ascorbic Acid Oxidising Factors in Wheat

A continuous spectrophotometric assay was developed to measure ascorbic acid oxidation in crude Na₂SO₄ extracts of flour. The rate of ascorbic acid oxidation in flour extracts measured using this method was similar to the rate in flour-water suspensions and 2–4 fold less than the rate in dough measured using an indophenol-xylene extraction method. Flour extracts appeared to contain two ascorbic acid oxidising factors; one with optimal activity at pH 6·3 and 30 °C and the other with optimal activity at pH 10 and 40 °C. The pH 6·3 factor had properties similar to those of ascorbate oxidase (EC 1·10·3·3) in its pH and temperature stability, strong inhibition by NaN₃, KCN and diethyldithiocarbamate, inactivation by proteases, and greater stereospecificity towards -ascorbic acid than -isoascorbic acid. The pH 6·3 factor was most concentrated in the pollard milling fraction of wheat and was lowest in flour. The pH 10 factor had several properties indicating non-enzymic oxidation of ascorbic acid; it was not inactivated by proteases, it was inhibited poorly or not at all by the above ascorbate oxidase inhibitors, and it had low specificity for stereoisomers of ascorbic acid.     

一种适合杨树RNA提取的方法

本试验为三种杨树材料建立了一种杨树RNA提取的方法。本方法具有充分抑制材料中的多酚褐化,提高RNA产率;最大限度地去除多糖及次生代谢物质,避免与RNA共沉淀;去除蛋白质和DNA污染;提取时间短,质量高等特点。通过本方法提取的RNA OD260/OD280值在1.9~2.0之间,能够完全满足后续实验的要求,如体外翻译、cDNA文库构建、基因芯片和DDRT-PCR等。