植物组织中糖与糖醇乙酰化及毛细管气相色谱分析

介绍了一种用1-甲基咪唑为溶剂和催化剂、盐酸羟胺和乙酸酐为肟化和乙酰化试剂,对植物样品中糖与糖醇进行乙酰化衍生化后的气相色谱分离和质谱鉴定的分析方法。并对糖与糖醇乙酰化影响较大的反应温度、反应时间、反应物组成和反应物浓度等条件进行了比较研究,确定了糖与糖醇乙酰化各步反应的最佳反应温度和反应时间,分析了各组分间相互作用及其用量对衍生化效率的影响。对多种糖与糖醇乙酰化产物进行毛细管气相色谱分离、FID检测及GC-MS结构鉴定。研究证明, 在合适条件下应用此方法对糖与糖醇进行乙酰化,反应完全,产物单一,能得到理想的分离、检测和定量分析效果。适用于微量植物组织中多种单糖、双糖及其糖醇的定量分析。     

分析植物组织中海藻糖的气质联用及毛细管气相色谱法

介绍一种用1-甲基咪唑为溶剂和催化剂、盐酸羟胺和乙酸酐为肟化和乙酰化试剂,对植物样品中海藻糖等糖类物质进行乙酰化衍生化后的气相色谱分离、质谱鉴定的分析方法.以核糖醇为内标,通过校准曲线对植物组织中的海藻糖进行定量分析.此法测定海藻糖的最低量可达8.17×10-11g,适于植物样品中微量海藻糖的分析测定.     

植物组织中低聚糖乙酰化及毛细管气相色谱分析

建立一种用乙酰化衍生处理低聚糖并用毛细管气相色谱-FID进行分析的方法。以1-甲基咪唑为催化剂并以乙酸酐为乙酰化试剂,同时对植物样品中蔗糖、棉子糖和水苏糖等低聚糖乙酰化产物进行毛细管气相色谱分离和FID检测。确定了低聚糖乙酰化衍生物的毛细管气相色谱分析条件,并对低聚糖乙酰化反应条件及色谱分离条件进行了优化。结果表明,在80–1000ng·μL–1范围内线性关系良好,蔗糖、棉子糖和水苏糖的相关系数（R）分别为0.9952、0.9957和0.9877,并且精准度与回收率均较高。使用该方法对低聚糖进行乙酰化反应重现性好、所需样品材料及试剂量少且污染毒害小,能够得到理想的分离、检测和定量分析效果,适用于少量植物组织中低聚糖的定量分析。该方法在食品、医药检测和基础科学研究领域均具有广泛的适用性及参考价值。     

植物组织中低聚糖乙酰化及毛细管气相色谱分析

建立一种用乙酰化衍生处理低聚糖并用毛细管气相色谱-FID进行分析的方法。以1-甲基咪唑为催化剂并以乙酸酐为乙酰化试剂, 同时对植物样品中蔗糖、棉子糖和水苏糖等低聚糖乙酰化产物进行毛细管气相色谱分离和FID检测。确定了低聚糖乙酰化衍生物的毛细管气相色谱分析条件, 并对低聚糖乙酰化反应条件及色谱分离条件进行了优化。结果表明, 在80–1 000 ng·μL^–1范围内线性关系良好, 蔗糖、棉子糖和水苏糖的相关系数(R)分别为0.995 2、0.995 7和0.987 7, 并且精准度与回收率均较高。使用该方法对低聚糖进行乙酰化反应重现性好、所需样品材料及试剂量少且污染毒害小, 能够得到理想的分离、检测和定量分析效果, 适用于少量植物组织中低聚糖的定量分析。该方法在食品、医药检测和基础科学研究领域均具有广泛的适用性及参考价值。     

气质联用定量分析放线菌全细胞单糖方法的研究*

采用气相色谱－质谱联用仪分析了近百株放线菌的全细胞水解液单糖。放线菌全细胞糖经酸水解、氢化还原和乙酯化生成糖醇乙酸酯衍生物通过气相色谱－质谱仪定性、定量分析。鼠李糖、核糖、阿拉伯糖、木糖、马杜拉糖、甘露糖、葡萄糖和半乳糖的糖醇乙酸酯衍生物在这种条件下得到了良好地分离。计算各糖的峰面积之比确定它们的相对百分含量。     

气相色谱-质谱联用技术及其在代谢组学中的应用

代谢组学是以高通量、高灵敏度、高分辨率的现代仪器分析方法为手段,对细胞、体液、组织中所有代谢物进行无偏向的定性与定量分析的一门学科。气相色谱-质谱联用技术具有较高的检测灵敏度和鉴定准确度,通过标准谱图库的比对可对代谢物进行快速的鉴定,因此被广泛应用于生物样品的代谢产物的检测中。文中对近年来气相色谱-质谱联用技术的发展以及在代谢组学研究中取得的成果进行了综述。首先介绍了气相色谱-质谱联用技术的分类和常用的样品衍生化方法;继而从样品预处理、定性与定量分析、数据分析三方面介绍了气相色谱-质谱联用技术分析代谢物的方法,并系统地对该技术在微生物、植物、疾病诊断领域的应用实例进行了评述;最后提出了当前气相色谱-质谱联用技术在代谢组学研究中存在的问题并对后续的研究进行了展望。     

糖类甲基化分析的进展

<正> 自从Hakomori使用甲基亚磺酰碳阴离子进行甲基化分析糖脂及多糖以来,经过San-dford和Conrad,及Stellner的改进,特别是用气相色谱-质谱联用定性、定量分析各种乙酰化的部份甲基化糖醛醇,甲基化分析目前已经成为糖链结构测定的最主要的方法之一。在研究糖的缀合物(Glycoconjugate) 的结构及其在细胞识别中的作用方面愈来愈重要了。 然而这一方法仍然存在着一些不能令人满意的地方。如试剂的制备及衍生化过程冗长、     

溴化马来松香的合成、表征及其阻燃性的研究

本文以马来松香与液溴加成,合成了溴化马来松香;研究了反应温度、原料的摩尔比、反应时间等因素对反应过程及产物性能的影响.用FT-IR、1H NMR和TG对溴化马来松香进行了表征.结果表明,当反应温度为-2～6℃,反应时间5～6 h,反应物的当量配比约为1.2时,收率可达87.9%.溴化马来松香具有较好的阻燃性,同时也拓宽了松香的应用范围,提高了松香的附加值.     

植物挥发性单萜经土壤载体的化感作用——以三裂叶豚草(Ambrosia trifida L.)为例

植物释放的挥发性单萜在生态系统中起着重要的作用,这些单萜不仅能以空气为载体对其他植物显示直接的化感作用,而且也能以土壤为载体进行间接的化感作用.通过对三裂叶豚草挥发物对植物种子萌发和土壤微生物种群影响及其化学成分的鉴定研究,验证了以单萜类物质为主的三裂叶豚草挥发物可以经土壤载体对其他植物及土壤微生物显示化感效应.还对植物挥发物化学成分鉴定的GC(气相色谱)和GC-MS(气相色谱-质谱联用)方法存在的一些误区进行了澄清,这将有助于对生态系统中植物挥发物化感作用的研究和认识.     

喜热噬油芽胞杆菌产生的生物乳化剂的组成与性质

由喜热噬油芽胞杆菌(Geobacillus thermoleovorans str 5366T)以正十六烷为碳源 55 ℃培养的发酵液中分离获得了一种生物乳化剂,经鉴定为糖-肽-脂复合物.该乳化剂中糖、肽、脂和烃的含量分别为29.4%、15.8%和35.8%.利用肽水解结合氨基酸分析、糖醇乙酰化结合GC-MS、脂肪酸甲脂化结合GC-MS等技术手段鉴定乳化剂中糖主要为D-甘露糖;主要氨基酸为谷氨酸、天冬氨酸、丙氨酸;构成脂的主要脂肪酸为十六烷酸、十八烯酸和十八烷酸.该菌及其代谢产生的乳化剂乳化性能良好,具有高温条件下应用的潜力.     

Characterization of Sugar and Polyphenolic Diversity in Floral Nectar of Different ‘Oblačinska’ Sour Cherry Clones

‘Obla?inska’ sour cherry, an autochthonous cultivar, is the most planted cultivar in Serbian orchards. Since fruit trees in temperate zone reward insects by producing nectar which ‘quality’ affects the efficiency of insect pollination, the aim of this study was analyzing of sugars and polyphenolics in floral nectar of 16 ‘Obla?inska’ sour cherry clones with different yielding potential. The contents of sugars and sugar alcohols were analyzed by ion chromatography, while polyphenolic profile was established using liquid chromatography/mass spectrometry technique. Fourteen sugars and six sugar alcohols were detected in nectar samples and the most abundant were fructose, glucose, and sucrose. Eleven polyphenols were quantified using available standards, while another 17 were identified according to their exact masses and characteristic fragmentations. Among quantified polyphenols, rutin, naringenin, and chrysin were the most abundant in nectar. Principal component analysis showed that some polyphenol components (naringin, naringenin, and rutin) together with sugars had high impact of spatial distribution of nectar samples on score plot.     

Sugar signalling and gene expression in relation to carbohydrate metabolism under abiotic stresses in plants

Sucrose is required for plant growth and development. The sugar status of plant cells is sensed by sensor proteins. The signal generated by signal transduction cascades, which could involve mitogen-activated protein kinases, protein phosphatases, Ca²⁺ and calmodulins, results in appropriate gene expression. A variety of genes are either induced or repressed depending upon the status of soluble sugars. Abiotic stresses to plants result in major alterations in sugar status and hence affect the expression of various genes by down- and up-regulating their expression. Hexokinase-dependent and hexokinase-independent pathways are involved in sugar sensing. Sucrose also acts as a signal molecule as it affects the activity of a proton-sucrose symporter. The sucrose transporter acts as a sucrose sensor and is involved in phloem loading. Fructokinase may represent an additional sensor that bypasses hexokinase phosphorylation especially when sucrose synthase is dominant. Mutants isolated on the basis of response of germination and seedling growth to sugars and reporter-based screening protocols are being used to study the response of altered sugar status on gene expression. Commoncis-acting elements in sugar signalling pathways have been identified. Transgenic plants with elevated levels of sugars/sugar alcohols like fructans, raffinose series oligosaccharides, trehalose and mannitol are tolerant to different stresses but have usually impaired growth. Efforts need to be made to have transgenic plants in which abiotic stress responsive genes are expressed only at the time of adverse environmental conditions instead of being constitutively synthesized.     

Quantitative determination of phenyl isothiocyanate-derivatized amino sugars and amino sugar alcohols by high-performance liquid chromatography

Simple and rapid methods for the preparation of phenylthiocarbamyl (PTC) derivatives of amino sugars and amino sugar alcohols and their quantitative determination with high sensitivity (less than 10 pmol) by C18 reversed-phase high-performance liquid chromatography are described. Rapid sample preparation of the phenyl isothiocyanate (PITC)-derivatized amino sugars and amino sugar alcohols was achieved by a simple extraction of the reaction mixture with chloroform to remove the excess PITC and its adducts. Baseline separation of the PTC derivatives of amino sugars and amino sugar alcohols was obtained within 30 min, using a simple solvent system consisting of 0.2% each of n-butylamine, phosphoric acid, and tetrahydrofuran. The mobile phase containing n-butylamine, in conjunction with a C18 stationary phase, mimics the conditions for the separation of carbohydrates on an amino-bonded column. GlcNH2 and GalNH2 derived from the initial protein-sugar linkages were also separated from the amino acids for quantitative estimation of sugar chains in glycoproteins. Amino sugar alcohols gave single reaction products with PITC while the reaction with amino sugars was accompanied by the formation of secondary products. Apparently the secondary products were formed in an acid-catalyzed intramolecular cyclization of the PTC-hexosamines involving the aldehyde functional group. Conditions were developed to stop the transformations and maintain the stability of PTC derivatives for their convenient determination by HPLC.     

Sugar Composition of O-Antigenic Lipopolysaccharides Isolated from Vibrio parahaemolyticus

Vibrio parahaemolyticus, a causative bacterium of food poisoning unique for its particular primary association with sea products, is now divided serologically into 11 or 12 O-forms based on agglutination and agglutinin-absorption tests. We determined the sugar composition of the somatic O-antigens, i.e., lipopolysaccharides (LPS), of representative strains of each O-form. Of particular interest is the absence of evidence for the presence of 2-keto-3-deoxy-octonic acid (KDO), a regular sugar component of gram-negative bacterial LPS, in any LPS examined, with the exception of 06. Furthermore, 07 and 012 LPS contained a KDO-like compound that is, however, not identical with KDO. Glucose, glucosamine, and L-glycero-D-mannoheptose were found as common sugar constituents. Three unidentified amino sugars, designated here as P1, P2, and P3, were found. Various combinations of each of these unidentified amino sugars, and of galactose, fucose, arabinose, D-glycero-D-mannoheptose, galactosamine, KDO, and the KDO-like substance were detected in accordance with the O-form of LPS. On the basis of the sugar composition, LPS of the 12 O-forms of V. parahaemolyticus can be classified into nine chemotypes, because 03, 05, and 011 LPS belong to the same chemotype and 07 and 012 to another chemotype.     

Sugar Repression of a Gibberellin-Dependent Signaling Pathway in Barley Embryos

Increasing evidence shows that sugars can act as signals affecting plant metabolism and development. Some of the effects of sugars on plant growth and development suggest an interaction of sugar signals with hormonal regulation. We investigated the effects of sugars on the induction of [alpha]-amylase by gibberellic acid in barley embryos and aleurone layers. Our results show that sugar and hormonal signaling interact in the regulation of gibberellic acid-induced gene expression in barley grains. The induction of [alpha]-amylase by gibberellic acid in the aleurone layer is unaffected by the presence of sugars, but repression by carbohydrates is effective in the embryo. [alpha]-Amylase expression in the embryo is localized to the scutellar epithelium and is hormone and sugar modulated. The effects of glucose are independent from the effects of sugars on gibberellin biosynthesis. They are not due to an osmotic effect, they are independent of abscisic acid, and only hexokinase-phosphorylatable glucose analogs are able to trigger gene repression. Overall, the results suggest the existence of an interaction between the hormonal and metabolic regulation of [alpha]-amylase genes in barley grains.     

高山被孢霉淬灭方法及胞内代谢产物的气相色谱-质谱分析比较

在花生四烯酸生产菌高山被孢霉代谢组学研究中,需利用胞内代谢物的提取手段并基于气相色谱-质谱（GC-MS）分析方法对其进行检测。比较了3种胞内代谢物提取方法及不同色谱柱条件下GC-MS分析结果。研究表明：采用冷甲醇淬灭分别较液氮直接淬灭及真空过滤后,减少了胞内代谢物的泄露并更好地实现了胞外及胞内代谢物的分离。在对代谢物分析的比较中,极性色谱柱（DB-FFAP）检出的代谢物仅为11种,主要为有机酸、醛类;而代谢物经衍生化后采用非极性色谱柱（DB-5）共检出32种化合物,主要为糖、糖苷及醇类。     

Sugar microanalysis by HPLC with benzoylation: improvement via introduction of a C-8 cartridge and a high efficiency ODS column

An HPLC protocol for sugar microanalysis based on the formation of ultraviolet-absorbing benzoyl chloride derivatives was improved. Here, samples were prepared with a C-8 cartridge and analyzed with a high efficiency ODS column, in which porous spherical silica particles 3 microm in diameter were packed. These devices allowed us to simultaneously quantify multiple sugars and sugar alcohols up to 10 ng/ml and to provide satisfactory separations of some sugars, such as fructose and myo-inositol and sorbitol and mannitol. This protocol, which does not require special apparatuses, should become a powerful tool in sugar research.     

Ion-exchange chromatography of sugars,sugar alcohols,and sugar acids using u.v. spectrometry for direct detection

Sugars, sugar alcohols, and sugar acids, after separation on an anion-exchange column, can be detected by using the strong absorption at λ ～200 nm. The absorption depends strongly on the type of eluant. The sensitivity of u.v. detection is superior to that using chromic acid by a factor of 2–30, but inferior to that for sugars using the orcinol reagent by a factor of ～100.     

Cell volumes and water contents of frog muscles in solutions of permeant sugars and sugar alcohols

1. Previous work has suggested that living cells may acquire and then maintain different water contents and hence volume, in solutions containing different concentrations of solutes that are permeant to the cell membrane. Toward better understanding of this phenomenon, two hypotheses were introduced: one hypothesis is based on the membrane-pump theory; another represents an extension of the polarized multilayer theory of cell water, a part of the association-induction (AI) hypothesis. To test the different predictions of these hypotheses, the water contents of frog muscle equilibrated at 25 degrees C in solutions of different concentrations of seven pentoses, seven hexoses, seven dissacharides, two trisaccharides, and six sugar alcohols were determined. 2. The earlier finding of sustained shrinkage of muscle cells in concentrated solutions of permeant solutes was confirmed once more. 3. In equimolal solutions of sugars and sugar alcohols with different steric conformations but the same or closely similar molecular weight(s), muscles had the same or closely similar water content(s). 4. In equimolal solutions of different sugars and sugar alcohols, the equilibrium water contents of the muscles increased with decreasing molecular weights of these solutes. 5. The water contents of muscles, equilibrated in 0.4 M solutions of different sugars and sugar alcohols, are positively correlated with the equilibrium distribution coefficients (or q-values) of the sugar and sugar alcohols in the muscle cell water with a linear correlation coefficient of +0.973. 6. The relationships between the equilibrium water contents of muscles (in solutions containing different concentrations of different sugars and sugar alcohols) and the concentrations of these sugars and sugar alcohols agree in general contours with that predicted by an equation derived on the basis of the polarized multilayer theory of cell water. 7. The experimental findings described above do not agree with the prediction based on the membrane-pump hypothesis; they do agree with all four predictions of the hypothesis based on the polarized multilayer theory of cell water.