栝楼果皮中腺嘌呤、鸟苷、瓜氨酸动态积累规律研究北大核心CSCD

对栝楼果皮生长期间主要活性成分腺嘌呤、鸟苷、瓜氨酸含量进行分析,探索活性成分积累规律。以长清产栝楼果皮为研究对象,从2013年7月3日到2013年10月26日采用高效液相色谱法进行腺嘌呤、鸟苷、瓜氨酸含量测定。实验表明腺嘌呤、鸟苷、瓜氨酸在生长期含量变化趋势是先降后升再降,至果皮表面颜色稍微泛黄时,腺嘌呤含量达到最高值0.1893 mg/g,至果皮表面颜色基本全黄、仅维管束凸起处为绿色时鸟苷含量达到最高值0.4128 mg/g,瓜氨酸含量达到最高值12.8834 mg/g。提示不同生长期栝楼果皮中腺嘌呤、鸟苷、瓜氨酸含量变化较大,果皮表面颜色基本为黄色仅维管束凸起处为绿色时为山东长清瓜蒌皮药材最佳采收期。     

栝楼果皮中腺嘌呤、鸟苷、瓜氨酸动态积累规律研究

对栝楼果皮生长期间主要活性成分腺嘌呤、鸟苷、瓜氨酸含量进行分析,探索活性成分积累规律。以长清产栝楼果皮为研究对象,从2013年7月3日到2013年10月26日采用高效液相色谱法进行腺嘌呤、鸟苷、瓜氨酸含量测定。实验表明腺嘌呤、鸟苷、瓜氨酸在生长期含量变化趋势是先降后升再降,至果皮表面颜色稍微泛黄时,腺嘌呤含量达到最高值0.1893 mg/g,至果皮表面颜色基本全黄、仅维管束凸起处为绿色时鸟苷含量达到最高值0.4128 mg/g,瓜氨酸含量达到最高值12.8834 mg/g。提示不同生长期栝楼果皮中腺嘌呤、鸟苷、瓜氨酸含量变化较大,果皮表面颜色基本为黄色仅维管束凸起处为绿色时为山东长清瓜蒌皮药材最佳采收期。     

红心火龙果籽的营养成分分析

以海南省东方市红心火龙果为研究对象,优化分离出果籽,测定果籽中的营养成分,并与白心火龙果籽进行对比研究,为火龙果加工中副产物的开发利用提供科学参考。红心火龙果籽-80℃冷冻干燥后,其水分、粗蛋白、粗脂肪、粗纤维、灰分及碳水化合物含量依次为:6.48,24.84,31.79,13.38、2.58 g/100 g和20.39 g/100 g果籽。高效液相色谱检测到果籽中含有丰富的α-生育酚和γ-生育酚,含量分别为5.78 mg/100 g和10.50 mg/100 g果籽。此外果籽中含有丰富的不饱和脂肪酸(占脂肪酸总含量的75.23%)和多种人体所需的必需氨基酸(占氨基酸总含量的26.62%)。研究结果为火龙果籽在食品、药品及日化用品中的应用提供数据支持。     

紫山药色素的提取工艺及抗氧化性能研究

研究紫山药色素的最佳提取工艺及其抗氧化性能。在单因素试验的基础上,采用L9(34)正交试验法,以pH示差法测定花色苷得率为考察指标,优化了溶剂提取法提取紫山药色素的工艺参数。通过DPPH体系测定该色素清除自由基能力。试验结果表明:紫山药色素属于花色苷类物质,优化的紫山药色素提取条件为:提取温度60℃,提取时间80 min,料液比1∶30,提取溶剂为0.5%盐酸乙醇溶液,提取液花色苷含量可达2.075mg/鲜紫山药g。紫山药色素提取液清除DPPH自由基的IC50为98.14μg/mL。紫山药具有开发功能性色素的潜力。     

响应面法优化火龙果茎甾醇的提取及纯化工艺研究

以火龙果茎为原料,研究火龙果茎甾醇的提取及精制工艺.利用响应面分析法对火龙果茎甾醇超声提取工艺进行优化.结果表明:超声波辅助提取火龙果茎甾醇的最佳工艺条件为提取时间57 min、超声功率143 W、液料比12∶1 (mL/g)、温度53℃,甾醇得率为2.693％‰.通过正交试验确定火龙果茎甾醇精制的最佳条件为:液料比为4∶1(mL/mg),结晶初始温度为55℃,养品时间为18h,此条件下火龙果茎甾醇的纯度达到87.6％.     

响应面法优化芦荟中抗氧化活性成分的提取工艺

对芦荟中抗氧化活性物质提取工艺及其成分进行研究,通过单因素实验和响应面优化,以提取物对DPPH自由基的清除率为抗氧化的考察指标,得到芦荟中抗氧化活性成分的提取工艺条件:提取温度29 ℃、料液比(g/mL)1:33、提取时间107 s、微波功率500 W,微波辅助水提,此条件下得到的提取物对DPPH自由基的清除率达91.414%.提取物活性成分分析表明:提取物中芦荟甙含量为1.5 mg/g、黄酮为1.13 mg/g、多酚为4.33 mg/g、多糖为126.36 mg/g.     

宣木瓜中黄酮的提取分离及含量的测定

从宣木瓜中提取总黄酮,并测定其含量.考察了回流提取、超声提取、微波提取等样品处理方法,用比色法测定宣木瓜中总黄酮含量.微波提取方法最好,芦丁在10～60μg/mL范围内具有良好的线性关系,r=0.9996;相对标准偏差为2%～3%,回收率在95%～98%之间.宣木瓜在7月下旬黄酮的含量最高,为5.93g/kg.     

红檵木花色素的微波提取与特性研究

对红檵木花色素的理化性质及微波提取方法进行了研究。结果表明：红檵木红色素可能属醇溶性黄酮类、其耐酸、耐轼化性很好,耐光氧化和耐热处理性极佳,而耐碱性和耐Fe^2 、Fe^2 、Cu、Pb^2 盐离子性较差。微波提取工艺研究表明：微波提取时间在设定的提取工艺三因素中居主要影响,其次是乙醇用量和浓度;只需一次微波处理便可将花瓣中红色素提完。进一步研究该色素的光照和热处理降解特性,结果表明：在设定的各处理温度下,该红色素降解均很缓慢,但其降解速度随设定处理温度升高呈加快趋势。在90C～100C的热处理下,其降解速度与热处理时间有A(最大光吸收)～t及lnA～t线性相关关系;当低于90C时,仅80C的设定热处理下有lnA～t直线相关,而A～t间都不呈线性关系。连续光照处理中,随处理时间延长其降解幅度极小,降解速度与光照时间不存在A～t及lnA～t线性相关。     

食用天然黑穗醋栗红色素研制初报

本研究采用颜色紫红的黑穗醋栗果实(主要是果皮)为原料,经酸性乙醇提取、过滤、浓缩、干燥等物理过程制取食用天然红色素。结果表明:该色素稳定性好,溶解性强,产品安全、无毒并具有营养价值,可以在食品工业上推广应用。     

王不留行刺桐碱提取工艺的比较研究

本实验采用高效液相色谱(HPLC)法检测王不留行刺桐碱含量为评价指标,分别采用单因素试验法和正交试验法对水浴回流提取和超声提取对王不留行刺桐碱的提取工艺进行比较。结果表明:超声提取王不留行刺桐碱的最佳工艺参数为液固比10∶1 mL/g,60%乙醇在350 W功率、80℃下提取40 min,在该工艺条件下王不留行刺桐碱含量为0.395 mg/g;水浴回流提取王不留行刺桐碱的最佳工艺参数为乙醇浓度75%,提取温度95℃,提取时间2 h,液固比12∶1 mL/g时,王不留行刺桐碱含量为0.345 mg/g。超声提取王不留行刺桐碱的提取效率、稳定性和重复性都优于水浴回流提取法。     

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.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

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.     

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.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

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。     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.