猪牙皂的化学成分和药理活性研究进展

猪牙皂主要含有多种三萜皂苷,具有抗炎、抗过敏、抗肿瘤、抗病毒、改善心肌缺血等药理活性.就近年来的研究成果作一综述,为猪牙皂的进一步开发和利用提供科学依据.     

海草生物活性成分的研究进展

本文综述了海草中生物活性成分的研究进展,其化学成分类型主要是苯酚类、黄酮类和二萜类化合物,生物活性主要包括抗菌、抗氧化、抗病毒、细胞毒性、抑制海藻生长和抗污损等.     

皂荚化学成分和生物活性的研究进展

我国的皂荚植物主要有皂荚、山皂荚、野皂荚和三刺皂荚.对皂荚的萜类、黄酮类、酚酸类、甾体类等化学成分及其抗菌、杀虫、抗病毒、抗肿瘤、免疫调节作用等生物学活性进行了综述.     

多糖及其硫酸化衍生物的抗病毒及免疫增强活性研究进展

近年来,人们发现多糖具有广泛的生物活性,并且越来越多的多糖被投入临床应用.其中,增强免疫和抗病毒作用是绝大多数多糖的主要药理作用,是多糖的共性.其中硫酸多糖因其显著的抗病毒和增强免疫活性而具有广阔的应用前景.文章就近年来国内外多糖分类及其硫酸化产物在抗病毒、增强免疫作用进行了综述.     

夏枯草的化学成分及药理作用研究进展

夏枯草主要含有三萜及其苷类、甾醇及其苷类、黄酮类、香豆素、苯丙素、有机酸、挥发油及糖类等成分,具有降压、降糖、抗茵、抗炎、抗过敏及抗病毒等作用,近年来由于其明确的抗病毒及抗癌作用受到研究者的重视。     

水溶性甘草多糖的分离纯化、结构及生物活性研究进展

甘草是广泛使用的中药材之一.甘草中含有多种活性物质,甘草多糖作为主要的活性大分子,具有抗肿瘤、抗病毒、抗氧化、抗补体以及免疫调节等生物活性.本文对近年来水溶性甘草多糖的分离纯化、结构解析以及生物活性研究的最新进展进行综述.     

甘草属植物中三萜类化合物的抗病毒作用研究进展

甘草为豆科甘草属植物,是我国重要的传统中草药,三萜类化合物是其主要活性成分之一。近年来,多种甘草属植物中的三萜类化合物被证明具有显著而广谱的抗病毒活性,成为抗病毒免疫研究的热点,并有望作为新型广谱抗病毒药物而被广泛应用于临床治疗中。本文综述了近年来国内外关于甘草酸、甘草甜素、甘草次酸及其衍生物等甘草属三萜类化合物的抗病毒作用研究进展,主要对该类化合物抗疱疹病毒、人类免疫缺陷病毒(human immunodeficiency virus,HIV)、肝炎病毒、严重急性呼吸综合征(severe acute respiratory syndrome,SARS)冠状病毒、流感病毒等的作用进行简要综述。     

天然抗烟草花叶病毒大分子物质研究进展

天然大分子物质主要包括蛋白、核酸和糖类.本文主要阐述了植物、动物和微生物中天然抗烟草花叶病毒大分子物质的研究与应用现状.关于这些大分子物质的抗病毒机理是多方面的,主要包括抑制病毒的侵染、对植物病毒增殖过程中的干扰和抑制作用、诱导植物的抗病性反应等,并对今后的研究进行了展望.     

MxA蛋白抗病毒机制及其应用前景

本文主要论述了MxA基因在Ⅰ型干扰素(IFN-α/β)或病毒诱导下可表达具广谱抗病毒作用的Mx蛋白(小鼠为Mx1,人类为MxA),并介绍了MxA蛋白的抗病毒谱及其机制,论述了MxA表达与病毒(HIV-1、HBV、HCV等)感染性疾病发生和发展的相关性,以及在判定IFN疗效中的应用.既有理论意义,又有广阔的应用前景.     

抗病毒免疫分子IFITMs的研究进展

干扰素诱导跨膜转运蛋白(Interferon inducible transmembrane proteins,IFITMs)是细胞内具有广谱抗病毒作用的抑制因子。其属于dispanin蛋白家族中的一个亚族并具有多种功能,其中其抗病毒功能是主要的研究热点。由于IFITMs,尤其IFITM3,能抑制禽流感等病毒的早期复制因而近年来得到了广泛的关注。目前研究发现,IFITMs主要通过核内体途径阻止病毒的入侵,从而影响病毒的复制。然而,其具体的抗病毒机制还未完全阐释清楚。本文就近年来IFITMs蛋白抗病毒功能的研究进展对其结构特征、细胞亚定位及其抗病毒机制等方面作一综述。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

医疗机构合理用药评价模型的构建研究

目的 针对医疗机构的合理用药水平进行评价研究。方法 根据医疗机构合理用药的具体要求,构建医疗机构合理用药评价指标体系,采用基于模糊群决策的方法和多指标评价分析法构建医疗机构合理用药评价模型。结果 构建了基于模糊群决策的医疗机构合理用药评价模型,并通过实例分析证明了评价模型的可行性。结论 建立的基于模糊群决策的医疗机构合理用药评价模型能够对医疗机构的合理用药水平进行科学评价,为提高医疗机构合理用药水平奠定基础。     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

青蒿素生物合成机理研究现状

本文总结了目前有关青蒿素生物合成机理方面的研究,主要包括青蒿素生物合成中生理因子的影响,青蒿素生物合成中间体及前体,青蒿素生物合成细胞定位等。指出了存在的一些问题及今后的研究发展前景。     

Discounting of sequences of delayed rewards of different amounts

The main purpose of this study was to determine whether the magnitude effect is present in cases where delayed sequences of rewards are discounted. The magnitude effect refers to the inverse relationship between the amount of a reward and the steepness of temporal discounting. This study was conducted with a computer program to estimate the indifference points, which served as indicators of the present subjective value of delayed sequences of small and large rewards. In the indifference point the subjective value of a single, immediate reward was equal to the subjective value of the delayed sequence (or to the value of a single delayed reward). As a control condition, we added an experimental task involving choices between single immediate and single delayed rewards. The experiment showed that the sequences of large rewards are discounted less steeply than are the sequences of small rewards. This finding suggests that the magnitude effect is present within the delayed sequences of rewards. In addition, when outcomes are relatively large, the results suggest that a single reward is discounted less steeply than the sequence of a total nominal value equal to this single reward. However, for relatively small rewards, the difference is not statistically significant. The less steep discounting of sequences of large rewards may explain the reward-bundling effect, which refers to less steep discounting of longer sequences than of shorter ones: longer sequences usually have greater overall nominal value. The present study was conducted on hypothetical rewards, and the results should be validated using real rewards.     

Estimation of the Timing of Perinatal Transmission of HIV

Knowledge of the timing of perinatal transmission of HIV would be valuable for the determination and evaluation of preventive treatments and would shed light on the mechanism of transmission. Estimation of the distribution of the time of perinatal transmission is difficult, however, because tests of infection status can only be undertaken after birth. DNA and RNA polymerase chain reaction (PCR) assays and HIV culture have been the most commonly used diagnostic tests for perinatal HIV infection. Such tests have high sensitivity and specificity, except when they are given shortly after infection. In this paper we use the time-dependent sensitivity of these diagnostic tests to make nonparametric and semiparametric inferences about the distribution of the time of perinatal HIV transmission as well as the cumulative probability of perinatal transmission. The methods are illustrated with data from a clinical trial conducted by the AIDS Clinical Trials group.     

Scales of spatial patterns of distribution of intertidal invertebrates

Few comparative studies of spatial patterns at different scales have examined several species in the same habitat or the same species over a range of habitats. Therefore, variability in patterns among species or among habitats has seldom been documented. This study quantifies spatial patterns of a suite of intertidal snails and a species of barnacle using a range of statistical techniques. Variability in densities was quantified from the scale of adjacent quadrats (over a distance of centimeters) to tens of kilometers. Significant differences in abundances occurred primarily at two spatial scales. Small-scale differences were found at the scales of centimeters or 1–2 m and, for many species on many shores, these accounted for most of the variability in abundances from place to place. These are likely to be determined by behavioural responses to small-scale patches of microhabitat. Large-scale differences in abundance were also found in most species at the scale of hundreds of meters alongshore. These are likely to be due to variation in recruitment (and/or mortality) because of limited dispersal by adults of these species. There was little or no additional variation among shores, separated by tens of kilometers, than was shown among patches of shore separated by hundreds of meters. Identification of the scale(s) at which significant differences in abundance are found focus attention on the processes (and the scales at which these processes operate) that influence patterns of distribution and abundance. Some of the advantages and disadvantages of various procedures are discussed.