栽培型和野生型黄花蒿提取物对朱砂叶螨杀螨活性比较

研究了野生型和栽培型黄花蒿叶丙酮提取物对朱砂叶螨的生物活性.结果表明:栽培型和野生型48 h的LC50分别为0.295和0.567 mg·ml-1,以栽培型的杀螨毒力较高;对2种提取物进行柱层析分离,野生型最终分离出19个馏分,栽培型分离出17个馏分,其中野生型的第11馏分与栽培型的第13馏分的杀螨活性在2.5 mg·ml-1,处理48 h的校正死亡率均为100%,与其他组分存在显著性差异;将杀螨活性较好的馏分进行毒力测定得出,处理48 h,野生型馏分11的LC50为0.120 mg·ml-1;栽培型馏分10、12和13的LC50分别为0.144、0.163和0.117 mg·ml-1.表明栽培型黄花蒿叶丙酮提取物对朱砂叶螨的触杀活性优于野生型.     

生防放线菌Fq24代谢产物对朱砂叶螨的生物活性

菌株Fq24是从健康番茄植株分离得到的一株植物内生放线菌.为了研究它对朱砂叶螨生物活性的影响,通过萃取、柱层析、气相色谱-质谱(GC-MS)等技术对Fq24代谢产物中的杀螨活性物质进行了分离和结构鉴定,并采用玻片浸渍法和叶片残毒法测定了这些代谢产物的生物活性.结果表明:石油醚萃取物对朱砂叶螨具有较强的触杀和产卵忌避作用.触杀作用的LC50为52.57 mg·L-1,产卵忌避作用的ODC50为43.18 mg·L-1.经GC-MS分析,流份S11的主要化学成分为棕榈酸甲酯,分子式为C17H34O2,是代谢产物中的杀螨活性物质之一.质量浓度为5 mg·mL-1的棕榈酸甲酯对雌成螨的24h校正死亡率为78.3％,对雌成螨24h产卵驱避率为81.6％.     

东莨菪内酯与双脱甲氧基姜黄素对朱砂叶螨致死效应模拟

采用玻片浸渍法测定了植物源杀螨活性物质东莨菪内酯、双脱甲氧基姜黄素及两者联合作用最佳增效配比(东:双=7:6)对朱砂叶螨雌成螨的致死效应,并采用时间-剂量-死亡率(TDM)模型进行模拟.结果表明:所建TDM模型均通过Hosmer-Lemoshow拟合异质性检验,朱砂叶螨雌成螨对3种药剂浓度变化的敏感程度为东莨菪内酯＞两者最佳配比＞双脱甲氧基姜黄素,双脱甲氧基姜黄素、东莨菪内酯和两者最佳配比对朱砂叶螨雌成螨的致死率高峰期分别为处理后32、28和32 h;处理后48 h的LC50和LC90分别为0.3324、0.2035、0.2195mg·mL-1和2.1198、0.9521、1.1617 mg·mL-1;浓度为1.0和2.0 mg·mL-1处理下,LT50分别为7.4、6.0、6.1h和6.4、4.8、5.0h.因此,东莨菪内酯与双脱甲氧基姜黄素最佳配比和东莨菪内酯具有相近的杀螨动态及时间-剂量效应,表现出较好的杀螨活性和增效作用,具有一定的开发利用价值.     

瑞香狼毒根提取物对山楂叶螨的生物活性

采用不同的生物活性测定方法比较了瑞香狼毒(Stellera chamaejasme L.)根部4种不同溶剂提取物的杀螨活性。结果表明,瑞香狼毒根提取物对山楂叶螨(Tetranychus viennensis Zacher)有很好的触杀和内吸活性。在触杀活性测试中,石油醚提取物和氯仿提取物的杀螨活性最高;在内吸作用中,乙醇、氯仿和石油醚提取物的杀螨活性均较高,杀螨效果显著。在对石油醚提取物的不同溶剂萃取物进行生物活性追踪测定中发现,石油醚萃取物和氯仿萃取物具有较高的生物活性,浓度为0.6 g.L-1,山楂叶螨的24 h校正死亡率分别达到93.22%和79.66%。     

双去甲氧基姜黄素对朱砂叶螨的生物活性及作用方式

在室温26℃±1℃、湿度60%～80%、光照14 h条件下,测定了天然植物活性成分双去甲氧基姜黄素对重要植食性害螨朱砂叶螨各螨态的触杀和熏蒸活性,对幼螨、若螨、成螨的驱避活性,以及对雌成螨的产卵抑制活性.采用玻片浸渍法测得双去甲氧基姜黄素对朱砂叶螨雌成螨48 h的LCso为0.433 mg·mL-1.在0.883 mg·mL-1(LC70)的浓度下,双去甲氧基姜黄素对朱砂叶螨不同螨态触杀活性的大小依次为幼螨＞若螨＞成螨＞卵,其中对幼螨24h和48 h的校正死亡率分别为60.0%和83.3%;对朱砂叶螨各螨态的熏蒸作用不明显,024h和48 h的校正死亡率均小于3%;对幼螨、若螨以及成螨均表现出较强的驱避作用,其中对幼螨的效果最好,不同处理时间的驱避率均在85%以上,其次是若螨,对成螨的驱避性相对较差,72 h的驱避率仅为47.8%.同时对雌成螨有明显的产卵抑制作用,处理后120 h产卵抑制率达到89.3%.表明双去甲氧基姜黄素对朱砂叶螨的主要作用方式为触杀、驱避和产卵抑制作用.     

东莨菪内酯对朱砂叶螨的驱避和产卵抑制活性

本研究采用叶碟浸渍法测定了东莨菪内酯对朱砂叶螨Tetranychus cinnabarinus(Biosduvals)雌成螨的触杀活性,采用选择性的半叶法测定了驱避活性,同时采用非选择性的全叶法测定了产卵抑制活性。结果表明,东莨菪内酯对朱砂叶螨雌成螨具有较好的触杀活性,采用叶碟浸渍法处理48h后的LC50为0.297mg·mL-1,LC30为0.105mg·mL-1,LC10为0.023mg·mL-1。采用LC50、LC30和LC103个浓度的东莨菪内酯处理雌成螨后,发现东莨菪内酯对雌成螨没有表现出明显的驱避活性,处理区和对照区24h和48h的着螨率均为50%左右;采用LC50和LC102个浓度处理雌成螨后表现出了一定的产卵抑制活性,平均产卵抑制率分别为23.02%和13.23%,而LC30对雌成螨的产卵量表现出了促进作用,平均产卵抑制率为-8.25%,这可能是由于毒物兴奋效应所致。本研究旨在为东莨菪内酯的进一步开发和应用奠定理论基础。     

姜黄素类化合物对朱砂叶螨的生物活性

分别用玻片浸渍法和叶片浸渍法测定了从姜黄中分离的姜黄素(curcumin,CCM)、去甲氧基姜黄素(demethoxycurcumin,DMC)和双去甲氧基姜黄素(bisdemethoxycurcumin,BDMC) 3种天然姜黄素类化合物对朱砂叶螨Tetranychus cinnabarinus Boisduval的成螨、若螨、卵的触杀活性以及对成螨产卵的抑制作用。结果表明：3种化合物对朱砂叶螨的生物活性大小依次为BDMC>DMC>CCM。3种化合物对朱砂叶螨成螨触杀活性最高者为BDMC,处理24 h和48 h其LC₅₀分别为1.18和0.51 mg/mL。对若螨触杀活性的大体趋势与对成螨的相同,其中处理48 h,BDMC对若螨的LC₅₀最小,为2.48 mg/mL。3种化合物对朱砂叶螨卵的触杀毒力也同样表现为BDMC>DMC>CCM。3种单体化合物都表现出一定的对朱砂叶螨雌成螨的产卵抑制作用。对姜黄素类化合物构效关系的初步研究,明确了甲氧基在姜黄素模板上对杀螨活性的贡献,对于开发具经济价值的叶螨类杀螨剂或者筛选先导化合物模板,具有一定的参考价值。     

采收时间对百里香芳香油产量和化学成分的影响研究

利用水蒸汽蒸馏方法研究了生长于中国西北部不同采收时期百里香花,叶,茎和全草芳香油含量和化学成分的变化,结果表明：不同采收时期对花和叶芳香油含量却很大,而对茎中芳香油含量的影响较小,最佳采收时期在盛花期,此时不仅芳香油含量高,而且油中百里香酚和香酚的含量也高。气－质色谱图上出现了53中化合物,鉴定了其中的41中,占总成分的94．419％,芳香油中以百里香酚,香芹酚,对聚伞花素和松油烯为主,它们的含量在整个生长时期从43．953％,增加47．810％。     

柑桔提取物中主要成分的杀螨活性评价

【目的】研究柑桔提取物中主要杀螨活性成分,为柑桔提取物作为杀螨剂的使用奠定基础。【方法】采用乙醇、丙酮、乙酸乙酯、石油醚4种溶剂对北碚447的果皮与种子进行平行提取,对4种提取物进行杀螨活性评价。对北碚447的果皮乙醇提取物和乙酸乙酯提取物进行GC-MS分析,就其中主要成分进行杀螨活性评价,确定主要杀螨活性成分。【结果】发现柑桔乙醇提取物的杀螨活性最高;果皮提取物的杀螨活性高于种子;果皮和种子乙醇和乙酸乙酯提取物通过GC-MS分析共鉴定出35种成分,其中柠檬烯含量最高,和柠檬醛、4-松油醇、芳樟醇占提取物含量的85%以上;柠檬烯杀螨活性高于柠檬醛、松油醇、芳樟醇、?-蒎烯。【结论】柑桔提取物中主要的杀螨成分是柠檬烯、柠檬醛、4-松油醇、芳樟醇、?-蒎烯,以这些物质为主要有效成分的柑桔提取物类杀螨剂的研发具有重大意义。     

变叶裸实中抗癌成分美登素、美登普林及其他成分的分离和鉴定

结合应用简便的干柱层析,低压柱层析等技术,从变叶裸实中成功地分到了抗癌活性成分美登素和美登普林,分离步骤较已报道的方法简便。还分离出卫矛醇,木栓酮,β-香树脂醇,β-谷甾醇和山萘甙,山萘酚-7-氧-鼠李糖甙。     

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.