霍山石斛(Dendrobidium huoshanness)的组织培养

霍山石斛(Dendrobidium huoshanness)是重要的药用植物,在组培过程中,其营养器官脱分化困难。本文研究了霍山石斛拟原球茎(PLBs)诱导的适宜条件,发现假鳞茎下段是诱导拟原球茎适宜的外植体,低浓度的NAA和CPPU的诱导效果较好,黑暗培养可缩短诱导时间,提高诱导率。     

硝普钠、植酸和水杨酸对悬浮培养的霍山石斛原球茎生长和生理活性的影响

在建立霍山石斛的液体悬浮培养技术的基础上,添加诱导子硝普钠（SNP）、植酸（PA）和水杨酸（SA）。3种诱导子均可促进霍山石斛原球茎中生物碱的积累,0.1mmol·L-1SNP、7.5g·L-1PA和100μmol·L-1SA处理的原球茎,其生物碱含量分别为不作处理的2.02倍、1.84倍和1.62倍。促进霍山石斛生物碱积累的适宜诱导子为SNP,其适宜浓度为0.1mmol·L-1。高浓度的3种诱导子均导致培养液酸化,原球茎的相对电导率上升,其生物量和生物碱含量明显下降。     

霍山石斛种子萌发及原球茎发育的解剖结构观察

正霍山石斛(Dendrobium huoshanense C.Z.Tang et S.J.Cheng)根茎具有益精强阴、生津止渴和补虚羸等功效~([1]),被批准实施地理标志产品保护~([2])。为解决霍山石斛种子在自然条件下萌发困难和繁殖周期长等难题,已成功建立其离体快繁体系并工厂化生产~([3]),并对其植株营养器官的解剖结构~([4])及采用茎段诱导类原球茎的发育过程~([5])进行了研究。为进一步明确霍山石斛种子萌发和幼苗生长发育的原理,作者采用植物组织培养和石蜡切片技术,对霍山石斛种子萌发及原球茎发育过程中细胞和组织结构的变化进行了解剖观察,以期为     

锗对霍山石斛类原球茎悬浮培养细胞生长和多糖合成及氧化还原态的影响

为解决霍山石斛类原球茎液体培养细胞生长缓慢和代谢水平低下的问题,研究了不同浓度的锗(GeO2)对霍山石斛类原球茎增殖、多糖合成及碳氮利用的影响,分析了类原球茎细胞内还原糖、可溶性蛋白质含量、抗氧化酶活性以及细胞氧化还原态的变化。结果表明,适当浓度的二氧化锗(4.0mg/L)显著促进霍山石斛类原球茎的增殖和多糖的积累,最大细胞干重为32.6g/L,最大多糖产量为3.78g/L;显著提高胞内还原糖和可溶性蛋白质含量,超氧化物歧化酶和过氧化氢酶的活性明显升高,而过氧化物酶的活性则有所降低;氧化还原态分析发现,二氧化锗处理的细胞内还原型谷胱甘肽/氧化型谷胱甘肽的值明显提高,谷胱甘肽还原酶活性升高。添加适量的二氧化锗有利于细胞生长和多糖合成。     

蝴蝶兰花梗节间切段的类原球茎诱导与增殖

采用不同基本培养基和生长调节物质浓度组合,诱导蝴蝶兰花梗节间切段形成类原球茎和增殖的结果表明,花梗可见后10 d的切段诱导效果较好,较适宜的培养基为N_6 5.0 mg·L~(-1)6-BA 0.2 mg·L~(-1)KT 2 mg·L~(-1)活性炭。活性炭控制外植体褐化的效果明显优于维生素C。类原球茎增殖的适宜培养基为1/3MS 0.3mg·L~(-1)TDZ 0.2mg·L~(-1)NAA 2g·L~(-1)活性炭。     

霍山石斛人工种子包埋繁殖体和萌发

以腋芽、原球茎、不定芽为繁殖体, 制作霍山石斛人工种子, 利用正交设计探讨麦芽糖、6-BA/NAA、活性炭、海藻酸钠、离子交换时间五个因素对霍山石斛人工种子萌发的影响; 并对人工种皮的糖分泄漏率以及pH的变化进行测定, 另外对霍山石斛人工种子的贮藏和防腐做了初步研究。结果表明: 麦芽糖是影响霍山石斛人工种子萌发的主要因素, 适宜的处理组合为麦芽糖含量为4%、6-BA/NAA 10:1, 活性炭浓度0.1%, 海藻酸钠浓度4.0%, 将含有繁殖体的此配方溶液滴入2% CaCl2溶液中, 进行离子交换反应, 反应时间10 min。以腋芽, 原球茎, 不定芽为繁殖体的霍山石斛人工种子萌发率分别可达到65.6%、90.1%、75.2%, 萌发后幼苗的存活率分别为16.1%、80.6%和19.1%。4°C下贮藏20 d后, 霍山石斛人工种子以腋芽, 原球茎, 不定芽为繁殖体的萌发率分别为3.3%、10.6%、5.2%。包埋剂加入多菌灵后, 自然条件下萌发率分别可以达到6.8%, 13.8%, 7.9%。     

霍山石斛人工种子包埋繁殖体和萌发

以腋芽、原球茎、不定芽为繁殖体, 制作霍山石斛人工种子, 利用正交设计探讨麦芽糖、6-BA/NAA、活性炭、海藻酸钠、离子交换时间五个因素对霍山石斛人工种子萌发的影响; 并对人工种皮的糖分泄漏率以及pH的变化进行测定, 另外对霍山石斛人工种子的贮藏和防腐做了初步研究。结果表明: 麦芽糖是影响霍山石斛人工种子萌发的主要因素, 适宜的处理组合为麦芽糖含量为4%、6-BA/NAA 10:1, 活性炭浓度0.1%, 海藻酸钠浓度4.0%, 将含有繁殖体的此配方溶液滴入2% CaCl2溶液中, 进行离子交换反应, 反应时间10 min。以腋芽, 原球茎, 不定芽为繁殖体的霍山石斛人工种子萌发率分别可达到65.6%、90.1%、75.2%, 萌发后幼苗的存活率分别为16.1%、80.6%和19.1%。4°C下贮藏20 d后, 霍山石斛人工种子以腋芽, 原球茎, 不定芽为繁殖体的萌发率分别为3.3%、10.6%、5.2%。包埋剂加入多菌灵后, 自然条件下萌发率分别可以达到6.8%, 13.8%, 7.9%。     

水杨酸对霍山石斛类原球茎细胞生长及多糖合成的影响

本研究考察了水杨酸对霍山石斛类原球茎悬浮培养细胞生长、多糖合成、碳代谢的影响,并研究了细胞生长、多糖合成以及蔗糖消耗的动力学。结果表明,水杨酸对霍山石斛类原球茎细胞生长有轻微的抑制作用,但能够显著改善类原球茎对碳源的利用,提高胞内可溶性糖的含量,从而促进多糖的合成,其中以添加100μmol/L浓度的水杨酸效果最好,培养18d时,多糖产量达到3.129g/L,为对照的1.63倍。建立的培养动力学模型能较好地反映水杨酸调控霍山石斛类原球茎悬浮培养过程中细胞生长、多糖合成和蔗糖消耗特性。     

真菌对铁皮石斛原球茎酶活性和胞外pH的影响*

小菇属真菌制成诱导子处理铁皮石斛的原球茎 ,引起原球茎胞外pH分两个阶段升高 ,不同方法制作的诱导子对胞外pH的影响不同。诱导子还诱导原球茎苯丙氨酸解胺酶 (PAL)、过氧化物酶 (POD)和脂氧合酶 (LOX)活性的升高。PAL和POD活性伴随着胞外pH的升高 ,也呈现两次升高的特点。经过诱导子两次处理的原球茎的PAL活性升高尤其明显。     

超声处理对霍山石斛类原球茎悬浮培养细胞生理代谢的影响

为了了解超声处理对霍山石斛类原球茎产生的生理效应,研究了超声波功率和超声时间对霍山石斛类原球茎悬浮培养细胞生长以及多糖和蛋白质合成的影响;分析了培养基中碳、氮利用、细胞内活性氧水平以及蔗糖转化酶、硝酸还原酶、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性的变化。结果表明,适当功率和时间的超声处理（300 W3 min）能显著促进霍山石斛类原球茎的增殖,最大细胞干重为34．6g·L^-1;明显促进培养基中碳和氮的利用;显著提高胞内可溶性多糖、可溶性蛋白质和H2O2的含量;细胞内蔗糖转化酶、硝酸还原酶以及SOD、CAT和POD的活性明显升高。适当的超声波处理能促进霍山石斛类原球茎的生长发育和提高细胞的生理活性。     

果树花芽孕育的研究概况

果树花芽孕育是一个成花因素积累的过程 ,也是芽顶端花原基形成前所必要的活动。随着研究手段的改进和水平的提高 ,近年来人们逐渐弄清了果树花芽孕育的概念、花芽孕育期间的重要生理生化变化以及外界因素调控花芽孕育的可能方式 ,而对果树花芽孕育调控基因的研究处于起步阶段。     

果树花芽孕育的研究概况

果树花芽孕育是一个成花因素积累的过程,也是芽顶端花原基形成前所必要的活动。随着研究手段的改进和水平的提高,近年来人们逐渐弄清了果树花芽孕育的概念、花芽孕育期间的重要生理生化变化以及外界因素调控花芽孕育的可能方式,而对果树花芽孕育调控基因的研究处于起步阶段。     

Time course of color induction in the honeybee

Color induction in the honeybee is investigated in color discrimination experiments. An individual bee walks in a dark arena and is trained to a self-luminant stimulus presented from below. In the dual-choice tests the dark background is replaced by a colored induction stimulus. Choice behavior is recorded by TV camera and analyzed by computer. Successive color induction is separated from simultaneous induction by analysis of the walking paths. Only successive color induction occurs. Simultaneous effects are not observed. That is a stimulus acts as a color inducing stimulus only when the bee crosses this stimulus. Thus, the color perceived by a given eye region is found to be dependent on the viewing history, but not on the stimuli presented simultaneously on neighboring parts of the retina. Color induction in the honeybee described in terms of selective sensitivity decrease (adaptation) does not explain all behavioral effects induced by the stimulus. The time course of successive color induction is calculated from the exposure times to the induction stimulus and from the choice behavior. The data suggest that color induction is complete after a few seconds. Photoreceptor adaptation is sufficient to explain the observed time course.     

Spatial and temporal coincidence of induction processes and gap-junctional communication in Patella vulgata (Mollusca,Gastropoda)

In the early development of the gastropod mollusc Patella vulgata, two inductive processes take place between the animal and vegetal hemispheres. One is the induction of the vegetally-located stem cell of the mesoderm (the 3D macromere) by the first-quartet micromeres (which are located in the animal hemisphere). The other is the induction of dorsoventral symmetry in the first-quartet micromeres by the 3D macromere. As a consequence of the latter induction process, a dorsoventrally-organised prototroch is formed. In this paper, the moment of 3D induction is determined by deleting the inducing first-quartet micromeres at successive stages of development. Furthermore, the role of gap junctions in the two above-mentioned induction processes is investigated. This was done by studying lucifer yellow dye transfer between the 3D macromere and the first-quartet micromeres, in relation to these two induction processes. Analysis of the pattern of dye-transfer in vivo, in sections and with confocal laser scanning microscopy demonstrated that the moment of dye transfer coincides with the moment of 3D induction and with the moment of induction of the dorsoventral pattern of the prototroch. This indicates that gap-junctional communication may be involved in these two induction processes.     

Economically feasible induction of the bacteriophage λQ − mutant in Escherichia coli

Cost-effective induction of bacteriophage 5Q^m in Escherichia coli on reporter-protein production is presented. Long-duration temperature induction increases the mortality of bacterial hosts and decreases the productivity efficiency; however, sufficient time span of induction is essential to overcome the induction threshold. Thus, the optimal duration for cost-effective induction is approximately 30 min, since the benefit of induction longer than 30 min is unlikely to pay off the expense of significant host viability loss. Global optimization of economically feasible induction occurs at a critical optical density of ca. 1.0 for 30 min duration at 38v°C.     

Regulation of beta-galactoside alpha 2,6-sialyltransferase gene expression by dexamethasone

The hepatic acute phase response is accompanied by increased levels of Gal beta 1-4GlcNAc alpha 2,6-sialyltransferase activity in liver and in circulation. Previous studies suggested that cytokines and glucocorticoids mediate the induction of this sialyltransferase activity. In this study the regulation of sialyltransferase expression by dexamethasone in H35 rat hepatoma cells is assessed by Northern hybridization and enzyme activity assays. Exposure of H35 cells to 1 microM dexamethasone for 24 h causes a 3-4-fold enrichment of sialyltransferase mRNA and a corresponding increase in enzymatic activity. The induction of sialyltransferase mRNA begins within 3 h of dexamethasone treatment and reaches a plateau within 24 h. Sialyltransferase mRNA induction is dose dependent; the minimum concentration of dexamethasone necessary for induction is 10(-8) M, and induction was maximal at 10(-6) M. Induction is sensitive to actinomycin D, suggesting that regulation may be exerted by altering the rate of mRNA synthesis. Puromycin and cycloheximide are ineffective in blocking induction, suggesting that de novo protein synthesis is not required for induction. Finally, dexamethasone alone is sufficient for maximum induction of sialyltransferase mRNA. In contrast, maximal induction of alpha 1-acid glycoprotein, a well studied hepatic acute phase reactant, requires both dexamethasone and cytokines, implying that different pathways exist for the induction of participants in the acute phase response.     

Effects of fructose 6-phosphate and adenylates on the activities of rabbit liver fructose bisphosphatase and phosphofructokinase.

The kinetics of induction of cytosolic DT-diaphorase (NAD(P)H dehydrogenase-quinone, EC 1.6.99.2) by benzo(a)pyrene (BP) in the liver of the 8-day-old rat has been studied. After a lag phase of 8 h, DT-diaphorase reaches its maximum activity in three waves, with plateau levels of activity between 15–18, 26–36, and 40 h after administration of BP, at 4, 15, and 26 times the basal activity, respectively. A lower degree of induction of DT-diaphorase could be observed in the kidney cortex of the young rat and in the liver of the adult rat. No induction was observed in the fetal liver and in the adult kidney cortex. Lead acetate treatment of the adult rat resulted in induction of DT-diaphorase by BP in the liver and in the kidney cortex. Induction could not be observed in the regenerating liver of the adult rat. Experiments with picolinic acid (PA)—as a G₁ inhibitor—administered simultaneously or at different time intervals after BP administration resulted in an inhibition of induction, depending on the time of administration of picolinic acid. It is concluded that a mitotic cell cycle is necessary for DT-diaphorase induction by BP. Evidence is presented that BP acts in late G₁. The kinetics of induction of aryl hydrocarbon hydroxylase (AHH) by BP in liver microsomes of the 8-day-old rat has been compared with the induction of cytosolic DT-diaphorase. The effect of PA on the induction of AHH has also been studied. In view of the differences in kinetics of induction and in the effects of PA, it is concluded that the induction of AHH and that of DT-diaphorase are dissociated. AHH induction may take place in all hepatocytes, in contrast to DT-diaphorase induction.     

Effect of induction temperature on the production of malaria antigens in recombinant E. coli

As part of a process development campaign, studies have been conducted to determine the influence of induction temperature on the expression of two different malaria antigens, RN1 and RT2. Single-step temperature inductions, in which growth at 32.0 degrees C is followed by a shift in temperature to a desired setpoint, show that there exists an optimum duration and temperature of induction which is product specific. Between an induction temperature of 39.5 and 44.5 degrees C RN1 yield is constant at ca. 0.20 g/g total soluble protein (TSP). RT2 yield approaches 0.20 g/g TSP only at elevated induction temperatures. The optimum temperature of induction for RN1 production is 39.5 degrees C, whereas, that for RT2 production is 41.0 degrees C. Above the optimum temperature of induction antigen concentration decreases owing to decreases in biomass. Furthermore, the maximum concentration of these two antigens differ by a factor of four. With increasing temperature of induction the extent of proteolysis of the products also appears to increase.