外源GABA对NaCl胁迫下番茄幼苗活性氧代谢及叶绿素荧光参数的影响

采用水培法,研究了外源添加2.5 mmol/L GABA(γ-氨基丁酸)对NaCl胁迫下‘金棚一号'番茄(Lycopersicon esculentum Mill.)幼苗活性氧(ROS)代谢及叶绿素荧光参数的影响.结果表明:NaCl胁迫处理导致番茄幼苗ROS积累,同时抗氧化酶(SOD、CAT)活性显著提高,但抗氧化酶活...     

昆虫γ-氨基丁酸受体竞争性拮抗剂的研究进展

γ-氨基丁酸（GABA）受体（GABAR）是杀虫剂的重要作用靶标之一,目前已商品化的作用于GABA受体的杀虫剂均属于该受体的非竞争性拮抗剂（NCAs）。研究表明,GABA受体竞争性拮抗剂（CAs）的结合位点与作用机制有别于非竞争性拮抗剂,但二者具有相似的功能,均有杀虫活性。因此,GABA受体竞争性拮抗剂也具有开发成杀虫剂的潜力,但目前竞争性拮抗剂类杀虫剂还处于研究阶段。本文对近十年来昆虫GABA受体竞争性拮抗剂的相关研究进行综述,希望引起农药研究者的关注。     

盐碱胁迫下GABA对番茄幼苗活性氧代谢及光合性能的影响

采用番茄‘中杂9号’为试验材料,在营养液中加入NaCl和NaHCO3模拟盐碱胁迫,研究外源GABA对幼苗生长、活性氧代谢及光合性能的影响。结果显示:与对照相比,盐碱混合胁迫处理的幼苗地下部和地上部鲜重均显著降低,虽然SOD、POD、CAT活性明显升高,但O_2·-产生速率和MDA含量仍显著增高,导致幼苗光合能力减弱;外源GABA显著增加了胁迫后的幼苗地上部和地下部鲜重,显著提高幼苗根系和叶片中的SOD、POD和CAT活性,显著降低O_2·-产生速率和MDA含量;幼苗光合能力也得到显著改善;而正常条件下外源GABA处理显著提高了幼苗的3种抗氧化酶活性,但对其他参数的影响较小。结果表明,外源GABA通过提高番茄幼苗抗氧化酶活性、降低O_2·-产生速率和MDA的积累;缓解了盐碱胁迫对幼苗光合系统的损害,提高了番茄幼苗的耐盐碱性。     

γ-氨基丁酸对热应激肉种鸡产蛋性能和繁殖性能的影响

本试验旨在研究γ-氨基丁酸(GABA)对热应激条件下肉种鸡产蛋性能和繁殖性能的影响,并从血清抗氧化和免疫功能及肝功能相关酶活等方面探讨其作用机理。选取360只28周龄岭南黄肉种鸡,随机分为4组,每组3个重复,每个重复30只鸡,分别在基础饲粮添加0(对照)、25、50、75 mg/kg GABA。预试期14 d,正试期56 d。结果显示:与对照组比,1)添加75 mg/kg GABA显著提高了肉种鸡产蛋率、平均蛋重和料蛋比(P<0.05),并显著提高了种蛋的受精率、孵化率、雏鸡初生重(P<0.05)及出雏率(P<0.01);添加25和50 mg/kg GABA也显著提高了种蛋孵化率和出雏率(P<0.05),添加25 mg/kg GABA还显著提高了雏鸡初生重(P<0.05)。2)添加75 mg/kg GABA显著提高了血清免疫球蛋白A(IgA)和免疫球蛋白M(IgM)及补体C4含量(P<0.05);添加25 mg/kg GABA也显著提高了血清IgM含量(P<0.05)。3)添加75 mg/kg GABA显著提高了血清超氧化物歧化酶活性和血清谷胱甘肽过氧化物酶活性(P<0.05)及总抗氧化能力(P<0.01),降低了血清丙二醛浓度(P<0.01);添加25 mg/kg GABA也显著降低了血清丙二醛浓度(P<0.05)。结果提示,饲粮中添加GABA具有提高热应激条件下肉种鸡产蛋性能和繁殖性能的作用。     

Calming effect of orally administered γ‐aminobutyric acid in Shih Tzu dogs

The calming effects of γ‐aminobutyric acid (GABA) by oral administration were investigated in four adult Shih Tzu dogs. Three dosage levels (1, 2 and 4 mg/kg body weight) and non‐administration were tested by an increase and decrease method. Changes in activity (for 1.5 h) and urinary cortisol levels (pre‐administration, 3 and 7 h later) of dogs were monitored after administration. Without reference to dosage level, the mean times spent standing (P = 0.06), sitting (P < 0.05) and walking (P < 0.05) tended to decrease compared to non‐administration. A significant depression in the urinary cortisol level was observed at 7 h after administration (P < 0.05). These results indicate that orally administrated GABA exerts calming effects on dogs as well as humans.     

大麦籽粒蛋白质及其相关功能成分含量的QTL分析

【目的】研究大麦籽粒蛋白质与功能成分含量的相关关系及其QTL,为功能大麦遗传改良、基因克隆及分子辅助育种奠定理论基础。【方法】以紫光芒裸二棱为母本,Schooner为父本构建包含193个株系的RIL群体,结合SSR技术和QTL Ici Mapping V3.3软件构建遗传连锁图谱,借助完全区间作图法(ICIM)对两年大麦籽粒蛋白质、总黄酮和γ-氨基丁酸(GABA)含量进行QTL检测;同时分析蛋白质、总黄酮和GABA含量之间的相关性。【结果】亲本及RIL群体籽粒蛋白质、总黄酮及GABA含量表现出较大差异,且呈连续变异正态分布,适宜进行QTL定位。构建了一张全长为2 224.29 c M,两标记间平均距离为16.48 c M的遗传连锁图谱,包括7个连锁群,135个标记位点。共检测到20个QTL,其中,控制蛋白质含量的9个QTL分别定位于1H、2H、4H、6H和7H连锁群染色体。表型变异率范围为4.11%—18.86%,解释表型变异率大于10%的3个主效QTL(13.30%、15.45%和18.86%)分别位于6H和7H染色体。经两年试验检测发现2个相同的QTL位点,分别位于4H BMAG0740—BMAG0808和6H Ebmac0806—GBM1270;控制总黄酮含量的7个QTL分别定位于2H、5H、6H和7H染色体。表型变异率范围为6.06%—29.01%,解释表型变异率大于10%的5个主效QTL(10.38%、15.27%、17.55%、24.17%和29.01%)分别位于2H、6H和7H染色体。经两年试验检测发现1个相同的QTL位点,位于7H EBmatc0016—Bmag0206;控制GABA含量的4个QTL分别定位于4H、5H、6H和7H染色体,表型变异率范围为5.44%—14.87%,最大变异率为14.87%的主效QTL位于7H染色体。控制蛋白质含量与总黄酮含量的基因同位于2H、6H和7H染色体,控制蛋白质含量与GABA含量的基因重合在4H、6H和7H染色体,控制总黄酮含量与GABA含量的基因同位于5H、6H和7H染色体。控制这三种成分的QTL主要位于6H和7H,尤其是6H Ebmac0806—GBM1270影响蛋白质、总黄酮和GABA含量,且加性作用方向一致,有极显著相关性。相关性分析结果表明,蛋白质、总黄酮与GABA含量之间呈极显著正相关。【结论】大麦籽粒蛋白质、总黄酮和GABA含量的相关性分析与其部分QTL定位结果一致,揭示了蛋白质和功能成分含量之间紧密的遗传关系。     

Propofol modulates inner retina function in Beagles

PURPOSE: To further understand a common veterinary anesthetic, propofol (2,6- di-isopropylphenol) and effects of infusion rates on the retinal neurons in Beagle dogs. METHODS: Standard full-field blue xenon-flash stimulation elicited responses of dark-adapted eyes, which were recorded from dogs before and after a propofol infusion rate increase. RESULTS: Electroretinogram b-waves increased significantly after the infusion rate increase and decreased with decline (P < 0.0001). Also, a weak significance (P = 0.041) for a-wave peak amplitude increase was found after infusion rate increase. The initial part (first 18 ms) of the leading edge of the a-wave remained unchanged. No significant differences in times to a- and b-wave peaks were found. CONCLUSION: Enhanced b-wave response and decline is due to sensitivity of postreceptoral cells, possibly interplexiform and amacrine cells, to propofol concentration.     

桑叶中γ-氨基丁酸含量的测定及其影响因素的研究

γ-氨基丁酸(γ-Aminobutyric acid,GABA)是动物中枢神经系统中的一种主要的抑制性神经递质,也是广泛存在于植物体内的一种与逆境胁迫有关的非蛋白氨基酸。研究表明,用AlCl3有效地去除桑叶中的水溶性色素后,采用分光光度法可以准确测定桑叶中GABA的含量。探讨了影响桑树叶片中GABA含量的主要因素:不同品种中GABA的含量不同,陕桑305最高,育71-1次之,湖桑32号和农桑14号含量稍低;相同叶位桑叶中GABA的含量为早期叶片高于后期叶片;同一时期不同叶位桑叶中GABA的含量随叶龄的增加逐渐降低,桑叶中GABA的含量在一天中以5:30时含量最低,17:00时含量最高。     

Mode of action of β-carboline convulsants on the insect nervous system and their potential as insecticides

Little information is available on the actions of β-carboline convulsants on insect GABA receptors or their potential as insecticides. Accordingly, two compounds (3-ethoxy-β-carboline, 3-EBC; dimethoxy-β-carboline-3-methyl ester, DMCM) were studied for their effects on Drosophila melanogaster larval neuron discharge and also in lethality bioassays on adult female D. melanogaster and adult male Blattella germanica. Recordings of nerve spiking in the isolated larval central nervous system showed that 3-EBC and DMCM inhibited nerve discharge, and this inhibitory effect was not additive with that of GABA, confirming that the inhibition was expressed through an action on the GABA receptor. Nerve blockage induced by β-carbolines could not be reversed by picrotoxinin, indicating that there may exist some overlap or negative allosteric coupling between the picrotoxinin and β-carboline binding sites. DMCM and 3-EBC effectively antagonized the effects of exogenously applied GABA in nerve preparations from insecticide-susceptible larvae. In contrast, preparations from the rdl strain of D. melanogaster, which possesses a GABA receptor that is highly resistant to cyclodienes and related convulsants, were less sensitive to the GABA antagonist effect of DMCM. Neither of the β-carbolines produced any appreciable mortality in insects, even when synergized with piperonyl butoxide or S,S,S-tributyl phosphorotrithioate, The toxicity of the β-carbolines is probably limited by their relatively weak effects on the GABA receptor and perhaps also by pharmacokinetic factors. These considerations, coupled with the cross-resistance observed in cyclodiene-resistant insects, suggest that the currently available β-carbolines are not viable as lead compounds for insecticide screening efforts. © 1997 SCI.