共查询到20条相似文献,搜索用时 921 毫秒
1.
专一识别脱落酸甲酯的单克隆抗体的制备与应用 总被引:2,自引:0,他引:2
专一识别2-顺(S)ABA甲酯的单克隆抗体来源于以ABA分子中的1-COOH为偶联位点合成的免疫原。它与游离态ABA和结合态ABA葡萄糖酯的交叉反应仅分别为1%与3.5%,而与ABA类似物,如2-顺-黄质醛、紫黄质以及ABA的2-反式异构体和(R)-对映体则无交叉反应。利用该抗体建立的高度灵敏和精确的ABAme酶联免疫测定法,其检测线性范围为0.048~1.52pmol。通过ABAmeELISA和GA1+3ELISA分析可知羊蹄叶片衰老与内源GA1+3/ABA比值的下降有关。 相似文献
2.
3.
苹果犁花芽分化期内源激素含量的变化(简报) 总被引:13,自引:1,他引:12
苹果梨花芽分化期间,可测到Z、ZR、IAA、ABA、CA3。生理分化期(花芽诱导期),GA3、ABA含量降低,Z、ZR、IAA增加;形态分化期,IAA降低,GA3、Z、ZR增加,ABA初期降低,后期增加。在分化期间,Z/GA3、ZR/GA3、Z/ABA、ZR/ABA、IAA/ABA比值均增高。 相似文献
4.
5.
6.
在苹果(MaluspumilaMil)果实细胞的可溶性组分中存在ABA特异结合位点,这些位点能与ABA形成稳定的3HABA蛋白结合复合物,而微粒体部分未表现出3HABA结合活性。可溶性组分对3HABA的结合效率与结合稳定性需要活体组织完整细胞的存在。ABA共价交联物ABALYCH,具有与ABA相同的抑制红苋菜(AmaranthustricolorL.)种子萌发的生物活性,能有效地竞争抑制果实组织圆片对3HABA的结合。通过ABALYCH对苹果果实组织圆片及果实组织游离细胞的荧光染色表明,未成熟果实的细胞外周被特异性地染色。在BSA存在的情况下,ABALYCH复合物被转运进细胞,形成密集的强烈荧光团。结果表明,ABALYCH与3HABA的竞争性结合发生在细胞质膜水平。 相似文献
7.
不同贮藏温度下马铃薯的萌芽和内源激素含量变化 总被引:4,自引:0,他引:4
马铃薯品种晋薯2号休眠期间,ABA含量下降,ZR,GA3,GA3/ABA增加,高温下种薯的ABA含量下降时间,GA3和ZR含量以及GA3/ABA比值增加时间均提前,休眠期缩短,低温下种薯的ABA含量下降,GA3含量和GA3/ABA比值增加均缓慢,ZR含量有升有降,休眠期延长。 相似文献
8.
牛奶子的组织培养及植株再生 总被引:1,自引:0,他引:1
1 植物名称 牛奶子 (Elaeagnusumbellata) ,又称甜枣、羊奶子。2 材料类别 幼苗的下胚轴。3 培养条件 ( 1 )MS 6 BA 1mg·L- 1 (单位下同 ) 2 ,4 D 3 IAA 0 .5 CH 30 0 ;( 2 )MS 6 BA2 2 ,4 D 2 NAA 0 .5 CH 30 0 ;( 3)MS 6 BA3 2 .4 D 1 IBA 0 .5 CH 30 0 ;( 4 )MS 6 BA1 .5 IAA 0 .5;( 5)MS 6 BA 1 .5 NAA 0 .5;( 6)MS 6 BA 1 .5 IBA 0 .5;( 7)MS 6 BA 0 .2 IAA 0 .5 GA 0 .5;( 8)MS 6 BA 0 .2 IAA 0 .1 GA… 相似文献
9.
识别未衍生化的13—羟化GAs及其葡萄糖苷的单克隆抗体 总被引:21,自引:0,他引:21
抗GA3 及其葡萄糖苷的MAB10单克隆抗体源于以GA3 中的3 位羟基(3-OH)为偶联位点,人血清白蛋白(HSA)为载体合成的GA3-3-HSA 免疫原. 该抗体对13-羟化GAs(13-OHGAs、GA1、GA3、GA5 等)和GA3 葡萄糖苷具有高亲和力. 7 位羧基的甲酯化可显著降低MAB10 对13-OH GAs的亲和力,而3-OH 的糖苷化却未降低其亲和力. 用该抗体建立的两种分别用于GA3 及其葡萄糖苷测定的酶联免疫吸附法(ELISA),其检测线性范围均为0.2~20 pm ol. 借助这两种ELISAs,研究了羊蹄(Rum ex japonicus)叶片中GA3 及其类似GAs和葡萄糖苷的动态变化.结果表明,叶片衰老与游离态GAs的糖苷化有关;而6-BA 延缓衰老则可能与其减缓GAs的糖苷化有关 相似文献
10.
花生胚发育过程中,子叶和胚轴中都出现BAPAase活性,花生种子明发时,子叶和胚轴中的BAPAase活性迅速上升,子叶中无新的BAPAase合成,胚轴中能重新合成BAPAase。ABA抑制子叶和胚轴中BAPAase的活性,抑制胚轴中BAPAase活性所需的外源ABA浓度更高,Act=D和CHM不能逆ABA对BAPAase活性的抑制作用。 相似文献
11.
12.
The channel activity of NMDA receptors is regulated by phosphorylation by protein kinases and by interaction with other proteins. Recombinant NR1/NR2A subtype NMDA receptor channels are potentiated by the protein tyrosine kinase Src, an effect which is mediated by a reduction in the high-affinity, voltage-independent Zn(2+) inhibition. However, it has been reported that Src-induced potentiation of NMDA receptor currents in hippocampus neurons is not mediated by a reduction in Zn(2+) inhibition. The post-synaptic density protein PSD-95 interacts with the C-terminus of NR2 subunits of the NMDA receptor. Here we demonstrate that PSD-95 eliminates the Src-induced potentiation of NR1/NR2A channels expressed in oocytes and reduces the sensitivity of the channels to Zn(2+). Our results reveal that the absence of Src-induced potentiation of PSD-95-coupled NR1/NR2A channels is not to due to the reduced sensitivity of these channels to Zn(2+). These results indicate that PSD-95 functionally modulates NR1/NR2A channels and explain why Src-induced potentiation of NMDA receptor currents in hippocampus neurons is not mediated by a reduction in Zn(2+) inhibition. 相似文献
13.
Polyclonal antibodies were raised in rabbits against the GABAA-receptor beta 3 subunit peptide sequence, KQSMPREGHGRHMDR-NH2 coupled to keyhole limpet haemocyanin. These anti-beta 3 379-393 antibodies immunoprecipitated in a dose-dependent manner specific benzodiazepine agonist binding sites from Na+ deoxycholate extracts of bovine cerebral cortex. In immunoblots, anti-beta 3 379-393 antibodies recognised two species with Mr 59,900 and Mr 57,200 in all preparations tested, which included crude detergent-solubilised, benzodiazepine affinity chromatography-purified receptor, anti-alpha 1 324-341 antibody, anti-Cys alpha 2 414-424 antibody and anti-Cys alpha 3 454-467 antibody immunoaffinity-purified GABAA-receptor subpopulations. These results provide evidence for the ubiquity and promiscuity of the GABAA-receptor beta 3 subunit. 相似文献
14.
Hirzel K Müller U Latal AT Hülsmann S Grudzinska J Seeliger MW Betz H Laube B 《Neuron》2006,52(4):679-690
Zn(2+) is thought to modulate neurotransmission by affecting currents mediated by ligand-gated ion channels and transmitter reuptake by Na(+)-dependent transporter systems. Here, we examined the in vivo relevance of Zn(2+) neuromodulation by producing knockin mice carrying the mutation D80A in the glycine receptor (GlyR) alpha1 subunit gene (Glra1). This substitution selectively eliminates the potentiating effect of Zn(2+) on GlyR currents. Mice homozygous for Glra1(D80A) develop a severe neuromotor phenotype postnatally that resembles forms of human hyperekplexia (startle disease) caused by mutations in GlyR genes. In spinal neurons and brainstem slices from Glra1(D80A) mice, GlyR expression, synaptic localization, and basal glycinergic transmission were normal; however, potentiation of spontaneous glycinergic currents by Zn(2+) was significantly impaired. Thus, the hyperekplexia phenotype of Glra1(D80A) mice is due to the loss of Zn(2+) potentiation of alpha1 subunit containing GlyRs, indicating that synaptic Zn(2+) is essential for proper in vivo functioning of glycinergic neurotransmission. 相似文献
15.
The effect of copper ions (Cu(2+)) on gamma-aminobutyric acid (GABA)-induced responses in acutely dissociated neurons from the rat sacral dorsal commissural nucleus (SDCN) was investigated using a nystatin-perforated patch recording configuration under voltage clamp conditions. The application of Cu(2+) to SDCN neurons reversibly suppressed the GABA (10 microM)-activated Cl(-) current (I(GABA)) in a concentration-dependent manner (1-1000 microM; IC(50) = 24.5 microM). In the presence of Cu(2+) (30 microM), the concentration-response curve of GABA was shifted rightward without reducing I(GABA) recorded under the maximally effective concentration of GABA, thus indicating a dependence of Cu(2+) action on GABA concentration. Inhibition of GABA (10 microM) responses by 30 microM Cu(2+) was essentially voltage independent and was not accompanied by a shift in the reversal potential of the currents. Cu(2+) antagonized the suppressive effect of Zn(2+) in a concentration-dependent manner, suggesting competition between Cu(2+) and Zn(2+) for similar binding sites. These data demonstrate that Cu(2+) is a potent inhibitor of GABA(A) receptor-mediated responses, implying a possible modulatory effect of Cu(2+) on GABAergic synaptic transmission in the mammalian SDCN. 相似文献
16.
Zinc has opposite effects on NMDA and non-NMDA receptors expressed in Xenopus oocytes 总被引:8,自引:0,他引:8
Pharmacological characterization of Zn2+ effects on glutamate ionotropic receptors was investigated in Xenopus oocytes injected with rat brain mRNA, using a double microelectrode, voltage-clamp technique. At low concentration, Zn2+ inhibited NMDA currents (IC50 = 42.9 +/- 1.3 microM) and potentiated both AMPA (EC50 = 30.0 +/- 1.2 microM) and desensitized kainate responses (EC50 = 13.0 +/- 0.1 microM). At higher concentrations, Zn2+ inhibited non-NMDA responses with IC50 values of 1.3 +/- 0.1 mM and 1.2 +/- 0.3 mM for AMPA and kainate, respectively. The potentiation of AMPA or quisqualate currents by Zn2+ was more than 2-fold, whereas that of the kainate current was only close to 30%. This potentiating effect of Zn2+ on AMPA current modified neither the affinity of the agonist for its site nor the current-voltage relationship. In addition, 500 microM Zn2+ differentially affected NMDA and non-NMDA components of the glutamate-induced response. The possible physiological relevance of Zn2+ modulation is discussed. 相似文献
17.
Daniel Reyes-Haro Jochen Müller Margarethe Boresch Tatjyana Pivneva Bruno Benedetti Anja Scheller Christiane Nolte Helmut Kettenmann 《The Journal of general physiology》2010,135(6):583-594
The calyx of Held (CoH) synapse serves as a model system to analyze basic mechanisms of synaptic transmission. Astrocyte processes are part of the synaptic structure and contact both pre- and postsynaptic membranes. In the medial nucleus of the trapezoid body (MNTB), midline stimulation evoked a current response that was not mediated by glutamate receptors or glutamate uptake, despite the fact that astrocytes express functional receptors and transporters. However, astrocytes showed spontaneous Ca2+ responses and neuronal slow inward currents (nSICs) were recorded in the postsynaptic principal neurons (PPNs) of the MNTB. These currents were correlated with astrocytic Ca2+ activity because dialysis of astrocytes with BAPTA abolished nSICs. Moreover, the frequency of these currents was increased when Ca2+ responses in astrocytes were elicited. NMDA antagonists selectively blocked nSICs while D-serine degradation significantly reduced NMDA-mediated currents. In contrast to previous studies in the hippocampus, these NMDA-mediated currents were rarely synchronized. 相似文献
18.
Klein RC Siarey RJ Caruso A Rapoport SI Castellino FJ Galdzicki Z 《Journal of neurochemistry》2001,76(6):1663-1669
The trisomy 16 (Ts16) mouse is an animal model for human trisomy 21 (Down's syndrome). The gene encoding the NR2A subunit of the NMDA receptor has been localized to mouse chromosome 16. In the present study, western blot analysis revealed a 2.5-fold increase of NR2A expression in cultured Ts16 embryonic hippocampal neurons. However, this increase did not affect the properties of NMDA-evoked currents in response to various modulators. The sensitivity of NMDA receptors to transient applications of NMDA, spermine, and Zn(2+) was investigated in murine Ts16 and control diploid cultured embryonic hippocampal neurons. Peak and steady-state currents evoked by NMDA were potentiated by spermine at concentrations < 1 mM, and inhibited by Zn(2+) in a dose-dependent and voltage-independent manner. No marked difference was observed between Ts16 and control diploid neurons for any of these modulators with regard to IC(50) and EC(50) values or voltage dependency. Additionally, inhibition by the NR2B selective inhibitor, ifenprodil, was similar. These results demonstrate that NMDA-evoked currents are not altered in cultured embryonic Ts16 neurons and suggest that Ts16 neurons contain similar functional properties of NMDA receptors as diploid control neurons despite an increased level of NR2A expression. 相似文献
19.
I. Khalilov X. Leinekugel M. Mukhtarov R. Khazipov 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2014,8(2):162-168
The intracellular blockade of GABAA-receptor-mediated currents is a useful approach to suppress the GABAergic conductance in a single cell and to isolate the glutamatergic component of network-driven activities. Previously an approach has been described allowing intracellular blockade of GABAA receptors by means of intracellular dialysis of a neuron with the pipette-filling solution, in which fluoride ions that hardly pass through the GABAA receptor channels substitute for Cl? and in which Mg2+ and ATP are omitted to induce rundown of the GABAA receptors during whole-cell patch-clamp recordings. However, the kinetics of suppression of GABAergic conductance and the effect on the currents mediated by glutamate receptors remain unknown. Here, using whole-cell recordings with fluoride-based, Mg2+- and ATP-free solution on CA3 hippocampal neurons of neonatal rats, we show that after 1 h of such dialysis, both spontaneous and evoked GABAA-receptor-mediated synaptic currents and responses induced by the GABAA receptor agonist isoguvacine were completely suppressed. Inward GABAergic postsynaptic currents were suppressed prior to outward currents. Synaptic responses mediated by AMPA receptors were not affected by the dialysis, whereas the NMDA-receptor-mediated postsynaptic currents were reduced by approximately 20%. Dialysis with fluoride-based Mg2+, ATP-free solution either fully blocked giant depolarizing potentials (GDPs) in CA3 pyramidal cells (n = 2) or reduced the charge crossing the membrane during GDPs and shifted the GDP reversal potential to more positive values (n = 5). The dialysis-resistant component of GDPs was mediated by glutamate receptors, since: (i) it reversed around 0 mV; (ii) it demonstrated a negative slope conductance at negative membrane voltages, which is characteristic of NMDA receptor-mediated responses; (iii) kinetics of the individual events composing the dialysis-resistant component of GDPs at negative voltages were very similar to those of AMPA receptor-mediated synaptic currents. Thus, this procedure can be useful to isolate the glutamate receptor-mediated component of neuronal network-driven activities. 相似文献
20.
Extracellular Zn2+ activates epithelial Na+ channels by eliminating Na+ self-inhibition 总被引:1,自引:0,他引:1
Inhibition of epithelial Na(+) channel (ENaC) activity by high concentrations of extracellular Na(+) is referred to as Na(+) self-inhibition. We investigated the effects of external Zn(2+) on whole cell Na(+) currents and on the Na(+) self-inhibition response in Xenopus oocytes expressing mouse alphabetagamma ENaC. Na(+) self-inhibition was examined by analyzing inward current decay from a peak current to a steady-state current following a fast switching of a low Na(+) (1 mm) bath solution to a high Na(+) (110 mm) solution. Our results indicate that external Zn(2+) rapidly and reversibly activates ENaC in a dose-dependent manner with an estimated EC(50) of 2 microm. External Zn(2+) in the high Na(+) bath also prevents or reverses Na(+) self-inhibition with similar affinity. Zn(2+) activation is dependent on extracellular Na(+) concentration and is absent in ENaCs containing gammaH239 mutations that eliminate Na(+) self-inhibition and in alphaS580Cbetagamma following covalent modification by a sulfhydryl-reactive reagent that locks the channels in a fully open state. In contrast, external Ni(2+) inhibition of ENaC currents appears to be additive to Na(+) self-inhibition when Ni(2+) is present in the high Na(+) bath. Pretreatment of oocytes with Ni(2+) in a low Na(+) bath also prevents the current decay following a switch to a high Na(+) bath but rendered the currents below the control steady-state level measured in the absence of Ni(2+) pretreatment. Our results suggest that external Zn(2+) activates ENaC by relieving the channel from Na(+) self-inhibition, and that external Ni(2+) mimics or masks Na(+) self-inhibition. 相似文献