声波刺激对菊花愈伤组织膜脂物理状态和膜脂代谢的影响

以蔗糖梯度法纯化的菊花 (Dendranthemamorifolium (Ramat.)Tzvel.)愈伤组织质膜微囊为材料 ,研究了声波刺激下质膜膜脂代谢和物理状态的变化。结果表明 ,一定强度 (10 0dB)和频率 (10 0 0Hz)的声波刺激使质膜磷酸二脂含量和二苯己三烯 (DPH)荧光偏振值降低 ,质膜光散射值、MC5 40荧光强度和磷酸单脂含量增加。表明一定强度和频率的声波刺激使质膜变疏松 ,膜的流动性增加 ,膜表面电荷密度和疏水性降低 ,膜脂合成代谢增加 ,分解代谢减弱。由此可见 ,膜脂物理状态和膜脂代谢对声波刺激极为敏感。     

渗透胁迫对小麦根质膜膜脂物理状态的影响

以两相法纯化的小麦(Triticum sativum L.)根质膜微囊为材料,研究了渗透胁迫下质膜物理状态的变化。结果表明,随着介质蔗糖浓度增加,质膜光散射值降低,二苯己三烯(DPH)荧光偏振值升高,MC540荧光强度增强,并且DPH长寿命组分的荧光寿命和平均寿命都缩短,暗示渗透胁迫使质膜微囊收缩变小,降低了质膜流动性和表面电荷密度,并且表明质膜的疏水性减弱。进一步实验发现,质膜内源色氨酸长寿命组分的寿命缩短,质膜H     

渗透胁迫对小麦根质膜膜脂物理状态的影响

以两相法纯化的小麦（TriticumsativumL．）根质膜微囊为材料,研究了渗透胁迫下质膜物理状态的变化。结果表明,随着介质蔗糖浓度增加,质膜光散射值降低,二苯己三烯（DPH）荧光偏振值升高,MC540荧光强度增强,并且DPH长寿命组分的荧光寿命和平均寿命都缩短,暗示渗透胁迫使质膜微囊收缩变小,降低了质膜流动性和表面电荷密度,并且表明质膜的疏水性减弱。进一步实验发现,质膜内源色氨酸长寿命组分的寿命缩短,质膜H －AT－Pase活力降低,暗示膜蛋白的构象和功能发生了改变。结果表明,质膜膜脂物理状态改变可能是植物感受渗透胁迫的原初响应。     

膜融合剂对脂质体及血影膜膜流动性的影响

本文用荧光探针ANS,DPH与A研究了几种膜融合剂对脂质体与血影膜流动性的影响.蔗糖使PS脂质体的脂双层流动性降低,探针越是在极性区流动性越小,说明蔗糖主要作用于脂双层的极性区;蔗糖也使血影膜流动性降低,此作用是可逆的.油酸甘油脂(GMO)使PS脂质体的流动性增加,且越是在疏水区内部,流动性增加得越大,说明GMO主要是作用于脂双层的非极性区:GMO也使血影膜流动性增加,此作用是不可逆的.二甲亚砜(DMSO)对血影膜的作用,两种不同荧光探针不一样,对DPH的作用出现双相让,低浓度与高浓度的作用结果分别与蔗糖和GMO的作用一致.     

膜脂物理状态的变化与肺腺癌细胞A549的顺铂耐药性

用荧光探剂DPH分别标记药物敏感的肺腺癌细胞A549和抗顺铂药物的肺腺癌细胞A549/DDP, 对其膜脂物理状态的变化研究结果表明, 对顺铂药物敏感的A549的DPH各向异性值(P)为0.162, 而抗顺铂药物的A549/DDP者为0.194, 统计分析表明二者具有明显的差异. 当用可探测细胞膜脂双层不同层次的荧光探剂2-AS, 7-AS和12-AS进一步测定不同层次的膜脂质分子的流动性变化时, 结果表明: 分别反映膜表层和中层的2-AS和7-AS的各向异性值, 对敏感性的A549细胞分别为0.134和0.144, 具抗药性的A549/DDP细胞则分别为0.171和0.178. 而反映膜深层脂质分子变化的12-AS的各向异性值二者却无显著差异. 这提示, 两种细胞膜脂流动性的变化主要反映在膜的表层和中层. 同时, 用MC540荧光探剂标记两种细胞膜在FCM (flow cytometry)上测定反映膜脂质分子头部堆积程度差异的二维散点图及频数分布直方图的结果分析也表明, A549/DDP细胞膜脂质分子的有序性增加, 即流动性降低. 用气相色谱测量两株细胞膜脂肪酸的不饱和度, A549/DDP细胞膜脂肪酸的不饱和度明显低于A549细胞, 进一步肯定了上述结果. 结果提示, 在药物长期作用下, 膜脂物理状态的变化亦可能是肿瘤细胞具有抗药性的原因之一.     

外源脂肪酸对莱氏衣原体膜流动性的影响——电子自旋共振与荧光偏振研究

生物膜类脂的物理性质直接影响膜的生理功能,膜的流动动性是反映膜脂物理状态的一个重要特征.本文采用电子自旋共振波谱及荧光偏振技术研究油酸,硬脂酸以及油酸和棕榈酸的混合物渗入莱氏衣原体膜后对膜流动性的影响.结果表明,上述外源脂肪酸均能增加膜的流动性,其中以油酸渗入膜后最为显著.油酸中双键的作用不仅仅局限于双键所在碳原子附近,而且能使整个膜脂双层各个层次上流动性都有增加.对于用荧光偏振和自旋标记顺磁共振二种技术所获得结果的异同也进行了初步讨论.     

外源芦丁预处理对水分胁迫下玉米幼苗的生理效应

以玉米(Zeamays L.)品种'郏单958'为材料.采用营养液水培法,研究了外源芦丁(Rutin)对聚乙二醇(PEG)胁迫下幼苗叶片质膜相对透性、脯氨酸、可溶性糖含量及保护酶活性的影响.结果显示:(1)在15%PEG-6000胁迫下,玉米叶片的MDA含量、质膜相对透性、脯氨酸和可溶性蛋白质含量均显著增加,保护酶SOD、CAT、POD活性显著升高.(2)一定浓度芦丁(>0.40 g/L)预处理可显著抑制水分胁迫下玉米幼苗叶片MDA含量的上升,降低叶片质膜相对透性,并诱导SOD、POD和CAT活性提高.降低脯氨酸和可溶性蛋白质含量.说明外源芦丁能够提高玉米幼苗的抗氧化作用,缓解水分胁迫引起的膜脂过氧化,保护细胞膜免受或减少损伤·达到提高植物抗旱性的目的.     

外源H_2O_2和·OH对大麦幼苗根系线粒体膜脂和流动性的伤害

以大麦 (H ordeum vulgare L.)为材料 ,研究了外源 H2 O2 和· OH对大麦根系呼吸速率、线粒体膜流动性和膜脂脂肪酸组成的影响。结果表明 ,1 0 mmol/L H2 O2 或· OH处理 4d,大麦幼苗根系呼吸速率和线粒体膜脂不饱和脂肪酸含量及脂肪酸不饱和指数下降 ,线粒体膜脂荧光强度增加 ,膜流动性下降 ,且 H2 O2 或· OH处理浓度 (在 0 .1～ 1 0 mmol/L范围内 )越高 ,膜脂流动性下降越明显。 H2 O2 和· OH处理的同时加入同浓度的抗坏血酸 (As A)和甘露醇 ,膜流动性明显增强或恢复     

外源H2O2和·OH对大麦幼苗根系线粒体膜脂和流动性的伤害

以大麦(HordeumvulgareL.)为材料,研究了外源H2O2和*OH对大麦根系呼吸速率、线粒体膜流动性和膜脂脂肪酸组成的影响。结果表明,10mmol/LH2O2或·OH处理4d,大麦幼苗根系呼吸速率和线粒体膜脂不饱和脂肪酸含量及脂肪酸不饱和指数下降,线粒体膜脂荧光强度增加,膜流动性下降,且H2O2或·OH处理浓度(在0.1～10mmol/L范围内)越高,膜脂流动性下降越明显。H2O2和·OH处理的同时加入同浓度的抗坏血酸(AsA)和甘露醇,膜流动性明显增强或恢复。     

冷害对黄瓜叶绿体类囊体膜的影响

研究了冷害温度(0℃,16h)对黄瓜(Cucumis sativus L.)叶绿体类囊体膜膜脂、膜蛋白成分的影响。在没有可见伤害症状的低温处理条件下,黄瓜叶片叶绿体类囊体膜膜脂成分已有变化,主要是磷脂酰甘油(PG)含量明显降低,但主要脂类成分单半乳糖基甘油二酯(MGDG)、双半乳糖基甘油二酯(DGDG)、硫代异鼠李糖甘油二酯(SQDC)和PG的脂肪酸组分没有明显的变化;类囊体膜上色素蛋白质复合体的变化以光系统Ⅱ捕光叶绿素a/b蛋白质(LHCⅡ)单体及寡聚体含量的变化最明显,低温处理使LHCⅡ单体比例增加。对提纯的LHCⅡ结合脂的分析表明,低温处理改变了LHCⅡ结合脂及其脂肪酸的组成,使PG含量降低。以上结果表明,LHCⅡ结合脂成分变化以及LHCⅡ寡聚体解聚可能是叶绿体类囊体膜受冷害的最初反应。     

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.     

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。     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

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.     

The mechanism of hatching of eggs of Haemonchus contortus

Fluid collected from hatching eggs of Haemonchus contortus contained a lipase which hydrolysed 2-naphthyl laurate (about 0·7 μmol naphthol freed /h/10⁶ eggs). The fluid also hydrolysed l-leucinamide (about 2·3 μmol leucine freed/h/10⁶ eggs). The fluid when added to normal or heated eggs caused ‘hatching’. ‘Hatching’ also occurred in exsheathing fluid from infective juveniles and in a preparation of pancreatic lipase containing leucine aminopeptidase. A purified mammalian leucine aminopeptidase in combination with several different lipases did not attack egg shells.The ‘spontaneous’ hatching of eggs of H. contortus was strongly inhibited by 1,10-phenanthroline, 10^?3M, and this inhibition was reversed by Zn²⁺. However, the inhibition of ‘hatching’ of eggs in externally applied hatching fluid, or the hydrolysis of leucinamide in hatching fluid was generally less marked.     

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.