酚类抗氧化剂清除自由基活性的理论表征与应用

筛选高效、低毒、价廉的抗氧化剂一直是自由基生物学的核心课题之一。由于筛选工作的复杂性与艰巨性,近来开始用理论方法加快这一过程。已发现许多理论参数与抗氧化剂清除自由基速率常数的对数有良好的相关性,其中尤以有征Ｏ－Ｈ解离能的△ＨＯＦ值研究得最深入。借助这一理论指标可解释酚类抗氧化剂的构效关系。对复杂抗氧化体系中抗氧化剂的活性差异也能给予较好的预测,而且还可指导新型抗氧化剂的理论构建,至此这一理论的有效     

邻二氮菲－Fe~（2＋）氧化法检测H_2O_2／Fe~（2＋）产生的羟自由基

报告检测Ｈ２Ｏ２／Ｆｅ２＋所产生羟自由基的新方法．羟自由基氧化反应后,邻二氮菲－Ｆｅ２＋的Ａ５３６明显下降,且△Ａ５３６与邻二氮菲,ＦｅＳＯ４及Ｈ２Ｏ２呈量效关系,随反应时间延长,△Ａ５３６依幂函数规律上升．此法试验结果表明,甘露醇,抗坏血酸及硫肥清除羟自由基作用呈明显的量效关系．     

中国伞滑刃线虫属─新纪录（真滑刃目：寄生滑刃科）

中国伞滑刃线虫属─新纪录（真滑刃目：寄生滑刃科）ＴＨＥＮＥＷＲＥＣＯＲＤＯＦＢＵＲＳＡＰＨＥＬＥＮＣＨＵＳＦＲＯＭＣＨＩＮＡ（ＡＰＨＥＬＥＮＣＨＩＤＡ：ＰＡＲＡＳＩＴＡＰＨＥＬＥＮＣＨＩＤＡＥ）￥ＹＩＮＧａｎ－ｌｉｕ;ＦＡＮＧＹｕ－ｓｈｅｎｇ（Ｄｅｐ...     

抗寒剂在福建上杭县早稻育秧中的应用效果

抗寒剂在福建上杭县早稻育秧中的应用效果薛德乾（上杭县临城农技站,３６４２００）ＡＰＰＬＩＣＡＴＩＯＮＥＦＦＥＣＴＳＯＦＴＨＥＣＯＬＤ－ＲＥＳＩＳＴＥＲＣＲ－４ＦＯＲＥＡＲＬＹ－ＲＩＣＥＳＥＥＤＬＩＮＧＣＵＬＴＵＲＥＩＮＳＨＡＮＧＨＡＮＧＣＯＵＮＴＹＯ...     

渗透胁迫下水稻幼苗中叶绿素降解的活性氧损伤作用

水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）幼苗在渗透胁迫下,随着胁迫强度的增加及时间的延长,Ｃｈｌ降解加剧,活性氧Ｏ－·２ 、Ｈ２Ｏ２ 及脂质过氧化产物丙二醛（ＭＤＡ）含量明显增加,抗氧化剂抗坏血酸（ＡｓＡ）还原型谷胱甘肽（ＧＳＨ）及胡萝卜素（ＣＡＲ）含量显著降低,叶绿素蛋白复合体（Ｃｈｌ－Ｐｒｏ）结合度松弛． Ｃｈｌ含量的降低和Ｏ－·２ 、Ｈ２Ｏ２ 及ＭＤＡ 含量呈显著的负相关,与ＡｓＡ、ＧＳＨ及ＣＡＲ含量的下降呈良好的正相关性．ＡｓＡ、α－生育酚（ＶｉｔＥ）及甘露醇预处理可使胁迫诱导的ＭＤＡ 增多及Ｃｈｌ降解延缓,而Ｆｅ２＋ 、Ｈ２Ｏ２ 及Ｆｅｎｔｏｎ 反应则刺激ＭＤＡ 增加． Ｆｅｎｔｏｎ 反应可加速Ｃｈｌ降解． 渗透胁迫下水稻幼苗Ｃｈｌ的降解可能主要是由Ｏ－·２ 和Ｈ２Ｏ２ 的代谢产物·ＯＨ氧化损伤之故     

含硒银杏叶清除羟基自由在的ESR研究

利用电子自旋共振技术（ＥＳＲ）研究了含硒银杏叶提取物对Ｈ２Ｏ２－Ｆｅ＾２＋体系产生的羟基自由基的清除作用。与ＳＯＤ、茶多酚相比,含硒银杏叶提取物对羟基自基也有很强的清除效果,增添了有实用价值的天然、无公害的清除羟基自由基的新资源。     

二种不同抗冷性水稻品种剑叶5’－核苷酸酶的细胞化学定位

二种不同抗冷性水稻品种剑叶５’－核苷酸酶的细胞化学定位陈善娜邹晓菊梁斌（云南大学生物系，昆明６５００９１）ＴＨＥＣＹＴＯＣＨＥＭＩＣＡＬＬＯＣＡＴＩＯＮＯＦ５’－ＮＵＣＬＥＯＴＩＤＡＳＥＩＮＳＷＯＲＤＳＨＡＲＰＥＤＬＥＡＶＥＳＯＦＴＷＯＤＩＦＦＥＲ...     

植物抗寒剂CR－4在湖南水稻生产中的应用效果

植物抗寒剂ＣＲ－４在湖南水稻生产中的应用效果段传嘉（湖南省水稻研究所,长沙４１０１２５）ＡＰＰＬＩＣＡＴＩＯＮＥＦＦＥＣＦＳＯＦＴＨＥＣＯＬＤ－ＲＥＳＩＳＴＥＲＣＲ－４ＩＮＲＩＣＥＣＵＬＴＵＲＥＯＦＨＵＮＡＮＰＲＯＶＩＮＣＥ￥Ｄｕａｎｃｈｕａｎ－ｊｉ...     

抗寒剂CR－4提高玉米幼苗抗寒力及质膜5＇－核苷酸酶冷稳定性的研究

抗寒剂ＣＲ－４提高玉米幼苗抗寒力及质膜５＇－核苷酸酶冷稳定性的研究孙龙华,简令成,王瑞萍（中国科学院植物研究所,北京１０００４４）ＳＴＵＤＩＥＳＯＦＣＯＬＤ－ＲＥＳＩＳＴＥＲＣＲ－４ＦＯＲＩＮＣＲＥＡＳＩＮＧＣＯＬＤＨＡＲＤＩＮＥＳＳＡＮＤＳＴＡＢＩ...     

植物胚胎学实验方法（七）同时显示胚中贮藏的淀粉,蛋白质和脂类的永久制片法

植物胚胎学实验方法（七）同时显示胚中贮藏的淀粉、蛋白质和脂类的永久制片法胡适宜（北京大学生物系,北京１００８７１）ＭＥＴＨＯＤＯＦＰＲＥＰＡＲＡＴＩＯＮＯＦＳＬＩＤＥＳＦＯＲＳＩＭＵＬＡＮＥＯＵＳＤＥＭＯＮＳＴＲＡＴＩＯＮＳＯＦＳＴＡＲＣＨＧＲＡＩＮ...     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV