工业合成甘氨酸其含量的测定——甲醛法

<正> 甘氨酸是医药、有机合成和生物化学研究中常用的氨基酸之一。工业上,甘氨酸可由一氯醋酸和氢氧化铵作用而成。而工业合成甘氨酸其含量的测定目前尚无国家标准。上海市卫生局药品检验标准中,甘氨酸的含量测定,采用高氯酸—冰乙酸非水滴定法。其它氨基酸的含量测定在工业上和医药上亦主要采用非水滴定和克氏定氮法,但是工业合成甘氨酸,由于其样品中有氯化铵的存在,用以上两法测定其准确性均受干扰。本文介绍用过量的氧化镁去除NH_3,在     

甘氨酸神经递质研究进展

甘氨酸是化学结构最简单的氨基酸,但具有复杂的功能。甘氨酸在中枢神经系统中是介导快速抑制性神经传递的一种重要的神经递质,在控制神经元兴奋性方面发挥重要作用。就其神经递质功能对甘氨酸的生物合成、释放与调控以及作用模式等方面的近年研究进展做一综述,对甘氨酸神经递质的全面认识将有益于炎性痛、痉挛状态以及癫痫等中枢神经系统疾病的诊断、预防及治疗。     

甘氨酸合成工艺革新

<正> 目前国内外生产甘氨酸都用化学合成法。文献报导的合成路线有三种方法,一氯醋酸氨化法,氰氮化法和乙内酰脲法。国内各厂生产甘氨酸都采用一氯醋酸氨化法,但所用氨化剂不同,一般用氨水、乌洛托品和碳酸氢铵等。我厂用液氨代替氨水作氨化剂生产甘氨酸获得成功,收率提高18.5%,成本下降43.2%,质量有明显提高。     

嗜盐菌中甘氨酸甜菜碱的合成途径及其生物学功能

在嗜盐菌长期的盐适应或短期的盐胁迫过程中,甘氨酸甜菜碱(又名三甲基甘氨酸,N,N,N-trimethylglycine)发挥着极为重要的作用。甘氨酸甜菜碱在嗜盐菌中的生物合成有2种途径:胆碱氧化途径和甘氨酸甲基化途径。前者以胆碱为底物,由胆碱脱氢酶(cholinedehydrogenase,BetA)和甜菜碱乙醛脱氢酶(betaine aldehyde dehydrogenase,BetB)经2次氧化生成甜菜碱;后者以甘氨酸作为底物,由甘氨酸肌醇甲基转移酶(glycine sarcosine N-methyltransferase,GSMT)和肌氨酸二甲基甘氨酸甲基转移酶(sarcosine dimethylglycine N-methyltransferase,SDMT)经3次N-甲基化生成甜菜碱。目前在JGI-IMG和EZBioCloud数据库中公布了134株嗜盐菌标准菌株的全基因组序列。其中,约56.0%的嗜盐细菌和约39.6%的嗜盐古菌拥有胆碱氧化途径所需的2个基因;约9.7%的嗜盐细菌和约0.7%的嗜盐古菌携带甲基化途径所需的2个基因。其中,8株嗜盐细菌同时拥有胆碱氧化途径和甘氨酸甲基化途径所需的全部基因。甘氨酸甜菜碱生物合成基因在典型微生物菌株或经济作物中的表达可以提高其耐盐抗逆能力,这种独特的优势已经引起科学家们强烈的兴趣,相信未来,嗜盐菌中甘氨酸甜菜碱生物合成领域内的科学理论和技术应用会有重大的突破。     

甘氨酸受体的研究进展

甘氨酸受体(GlyR)是中枢神经系统中一种重要的抑制性受体.GlyR是氯离子(Cl^－)选择性通道蛋白,属于配体门控离子通道超家族的一员.天然GlyR是由α和β亚基组装而成的五聚体.介绍了近年来有关GlyR的结构、功能、药理特性研究的重要进展,并结合本实验室工作,论述GlyR的调制及其可能机制.     

在银溶胶中甘氨酸和甘氨酸二肽的表面增强拉曼散射

甘氨酸及Gly-Gly和Gly-L-Pro二肽的表面增强拉曼散射谱与溶液内的普通拉曼谱的对比研究表明,银胶对COO、NH_2、C-N和C-C基团的振动有明显的增强.对CH_2基团无增强.Gly-Gly的SERS与pH有关,接近中性pH值时增强效果好,在酸性和碱性溶液内效果差.在 Gly-L-Pro的SERS谱中有强的酰胺Ⅰ带,而 Gly-Gly则几乎观察不到.     

野生大豆种子雨的研究

对野生大豆种子雨的时空动态及其与外界天气情况关系的初步研究表明,在野 生大豆整个种子雨的历程中,出现３个较为明显的炸荚和种子散落的高峰,并且峰的出现 与天气晴朗（相对湿度）相关,而与气温相关性不大．野生大豆种子雨的空间分布格局主要 是野生大豆种子炸荚的自身习性（炸荚弹力）和荚本身在植株上的空间分布有关,而与风 向（风力≤７级）关系不大．     

野生大豆种子雨的研究

对野生大豆种子雨的时空动态及其与外界天气情况关系的初步研究表明,在野生大豆整个种子雨的历程中,出现3个较为明显的炸荚和种子散落的高峰,并且峰的出现与天气晴朗(相对湿度)相关,而与气温相关性不大.野生大豆种子雨的空间分布格局主要是野生大豆种子炸荚的自身习性(炸荚弹力)和荚本身在植株上的空间分布有关,而与风向(风力≤7级)关系不大.     

NaCl胁迫下野生和栽培大豆幼苗体内离子的再转运

采用NaCl根际处理和叶面饲喂^22Na方法,研究了野生大豆(Glycine soja)——耐盐的BB52、盐敏感的N23232和栽培大豆(Glycine max)——较耐盐的Lee68幼苗在盐胁迫及解除过程中对Na^ 、Cl^-的吸收和再转运。结果表明,在NaCl根际处理12h过程中,BB52和Lee68幼苗根对Na^ 、Cl^-吸收和向茎、叶的运输逐渐增加,10h时趋于稳定,Na^ 、Cl^-含量高低顺序是根＞茎＞叶。但N23232的Na^ 、Cl^-含量则是茎＞根＞叶。在用NaCl对根处理10h后再解除NaCl处理的0～36h内,BB52吸收的Na^ 、Cl^-较多地留于根部或转运至根茎过渡区,叶中较少。N23232吸收的Na^ 较多地转运至茎部,而Cl^-含量在幼苗各部分无差异。叶片饲喂^22Na 10h后,BB52吸收^22Na较N23232多,并较多地向根部运输。从离子再转运角度讨论了BB52的耐盐性。     

The genomic relationships among six wild perennial species of the genus Glycine subgenus Glycine Willd.

Summary Based on meiotic chromosome behavior in intra- and interspecific hybrids, genome symbols were assigned to the following diploid (2n=40) Glycine species: G. canescens = AA; G. clandestina- Intermediate pod (Ip)=A ₁ A ₁; G. clandestina-Short pod (Sp)=BB; G. latifolia = B ₁ B ₁; G. tabacina = B ₂ B ₂; G. cyrtoloba = CC; and G. tomentella = DD. Genome symbol GG was reserved for the soybean, G. max. At metaphaseI, loose chromosome associations were observed in completely sterile interspecific hybrids whose parents differed in their genomes, suggesting some chromosome homologies among species. Although G. clandestina-Sp, G. latifolia and G. tabacina are morphologically distinct species, they differ only by a paracentric inversion. Similar observations were recorded for G. canescens and G. clandestina-Ip. Evidence is presented that demonstrates that G. tabacina (2n=80) and G. tomentella (2n=78, 80) are allotetraploid species complexes. Hybrid weakness, sterility, seedling lethality and seed inviability were found in intra- and interspecific hybrids.This research was supported in part by the Illinois Agricultural Experiment Station and the U.S. Department of Agriculture (Special grant 82-CRSR-2-2007). Travel grants to collect Glycine germplasm were received from the Rockefeller Foundation, the Illinois Soybean Program Operating Board, the National Science Foundation (INT76-14753) and the International Board for Plant Genetic Resources     

Localization of Glycine Neurotransmitter Transporter (GLYT2) Reveals Correlation with the Distribution of Glycine Receptor

Abstract: We studied by immunocytochemical localization, the glycine neurotransmitter transporter (GLYT2) in mouse brain, using polyclonal antibodies raised against recombinant N-terminus and loop fusion proteins. Western analysis and immunocytochemistry of mouse brain frozen sections revealed caudal-rostral gradient of GLYT2 distribution with massive accumulation in the spinal cord, brainstem, and less in the cerebellum. Immunoreactivity was detected in processes with varicosities but not cell bodies. A correlation was observed between the pattern we obtained and previously reported strychnine binding studies. The results indicate that GLYT2 is involved in the termination of glycine neurotransmission accompanying the glycine receptor at the classic inhibitory system in the hindbrain.     

Sulfhydryl Groups Modulate the Allosteric Interaction Between Glycine Binding Sites at the Inhibitory Glycine Receptor

We have investigated the effect of chemical reagents that modify sulfhydryl groups on the ligand binding properties of the glycine receptor (GlyR). The Hill coefficient (nH) for the displacement of [3H]strychnine binding by glycine was increased from approximately 0.8 to values significantly above 1 (approximately 1.2-1.4) in membranes pretreated with the disulfide-reducing agent dithiothreitol or glutathione. However, the affinity of strychnine or glycine for the GlyR was not affected by these treatments. This indicates that several glycine binding sites interact cooperatively for displacing bound strychnine under such experimental circumstances. A similar increase in the nH for glycine has been observed when the temperature of the binding assay was increased to 37 degrees C. Combination of dithiothreitol pretreatment and increased binding temperature led to nH variations similar to those observed with either of these treatments alone, a finding suggesting that their mechanisms of action are not independent. Conversely, modification of rat spinal cord membranes or of purified and reconstituted GlyR preparations with the sulfhydryl-alkylating agent N-ethylmaleimide or fluorescein-maleimide decreased nH values to approximately 0.5, without affecting glycine or strychnine affinities. This effect may be caused by an increased heterogeneity of GlyR populations. It is interesting that occupancy of the receptor by glycine or beta-alanine (but not by antagonists) specifically protects from the effects of the different sulfhydryl reagents. Moreover, the presence of some of the Eccles' anions, i.e., anions that permeate through the channels associated with GlyRs and gamma-aminobutyric acidA receptors, seems to be required for the action of both dithiothreitol and N-ethylmaleimide.(ABSTRACT TRUNCATED AT 250 WORDS)     

氯化钠胁迫下野生和栽培大豆幼苗体内的多胺水平变化

以通用的较耐盐的栽培大豆Lee68品种和对盐敏感的野生大豆N23232种群为参照,研究了盐胁迫下耐盐野生大豆BB52种群幼苗体内多胺(PAs)组分、含量及多胺氧化酶(PAO)活性的变化。结果表明,盐胁迫下BB52幼苗根PAs中Put和Spm含量下降较Lee68和N23232显著,但Spd含量下降较少．BB52叶片PAs中Put含量下降,Spd上升,(Spd+Spin)／Put值增加和Put／PAs值降低幅度与耐盐性呈正相关趋势．盐胁迫下,各材料根和叶中PAO活性上升,N23232上升最明显．探讨了多胺水平与BB52耐盐性的关系。     

Glycine fermentation by Clostridium histolyticum

Clostridium histolyticum grew on glycine, arginine, or threonine as sole substrate. Arginine degradation preceded that of glycine and partially inhibited that of threonine when two amino acids were present. Each amino acid seemed to be individually catabolized, not by a Stickland type of reaction. Glycine fermentation required the presence of complex ingredients. Therefore, an effect of selenite on glycine catabolism could only be demonstrated after scavenging selenium contamination by preculturing Peptostreptococcus glycinophilus in that medium. C. acidiurici was not suited as selenium accumulating organism as C. histolyticum was inhibited by the residual uric acid. Arginine catabolism was unaffected by seleniuum depriviation. The labelling pattern obtained in acetate after incubation of C. histolyticum with [1-¹⁴C]- or [2-¹⁴C]glycine strongly indicated the metabolism of glycine via the glycine reductase pathway.     

甘氨酸生产新工艺中Cl~-含量测定方法的研究

采用不同的氯离子(Cl-)含量测试方法(摩尔法、氯离子选择电极法、电位滴定法、电导法、比浊法),对甘氨酸合成中各步骤的产物分别进行Cl-含量测试,确定出相适应的测定方法。     

RAPD重建的大豆属植物的亲缘关系

利用８种ＲＡＰＤ引物（ＯＰＨ－２、ＯＰＨ－３、ＯＰＨ－５、ＯＰＨ－１２、ＯＰＨ－１５、ＯＰＨ－１６、ＯＰＨ－１８和ＯＰＨ－２０）对大豆属的２１份植物材料,其中包括Ｇｌｙｃｉｎｅ亚属的１０个种和Ｓｏｊａ亚属的３个种,进行了基因组指纹图谱构建。通过对获得的基因组指纹图谱的量化分析,利用Ｕｎｗｅｉｇｈｔｅｄｐａｉｒｇｒｏｕｐｗｉｔｈｍａｔｈｅｍａｔｉｃａｖｅｒａｇｅ（ＵＰＧＭＡ）对大豆属中的各个种进行了亲缘关系重建。重建的亲缘关系表明：Ｇ．ｔｏｍｅｎｔｅｌｌａ种中存在３种不同的进化类型,其分化距离已大于某些种种间的分化距离,它们可能是被形态遮蔽的３个种。Ｓｏｊａ亚属内３个种的分化关系同前人的研究推断相同,其亲缘关系很近,这一结果支持将这３个种归并为一个种的观点。但是重建的亲缘关系未能显示出大豆属两个亚属的划分格局。