Monitoring of metabolic profiling and water status of Hayward kiwifruits by nuclear magnetic resonance

The metabolic profiling of kiwifruit (Actinidia deliciosa, Hayward cultivar) aqueous extracts and the water status of entire kiwifruits were monitored over the season (June-December) using nuclear magnetic resonance (NMR) methodologies. The metabolic profiling of aqueous kiwifruit extracts was investigated by means of high field NMR spectroscopy. A large number of water-soluble metabolites were assigned by means of 1D and 2D NMR experiments. The change in the metabolic profiles monitored over the season allowed the kiwifruit development to be investigated. Specific temporal trends of aminoacids, sugars, organic acids and other metabolites were observed.The water status of kiwifruits was monitored directly on the intact fruit measuring the T₂ spin-spin relaxation time by means of a portable unilateral NMR instrument, fully non-invasive. Again, clear trends of the relaxation time were observed during the monitoring period.The results show that the monitoring of the metabolic profiling and the monitoring of the water status are two complementary means suitable to have a complete view of the investigated fruit.     

响应面法优化谷氨酰胺转氨酶交联大豆分离蛋白的工艺

研究了关于谷氨酰胺转氨酶(TGase)对于大豆分离蛋白(SPI)交联的影响;以凝胶强度为考察指标,采用响应曲面法(RSM)考察TGase含量,酶反应时间,酶作用温度对SPI凝胶性能影响规律,并优化得到最佳工艺参数;实验结果表明,酶的加入量,温度对大豆分离蛋白的凝胶强度有显著影响(p0. 05),得到蛋白凝胶性能最佳的工艺,在酶含量3. 63%,酶作用温度38. 15℃,酶反应时间2. 04 h时蛋白凝胶的凝胶强度达到极值301. 8;研究表明:TGase能够促进大豆分离蛋白形成良好的凝胶。     

NaCl对水稻谷氨酰胺合成酶活性及同工酶的影响

在营养液中 Ｎａ Ｃｌ的胁迫下,水稻根和叶的谷氨酰胺合成酶（ Ｇ Ｓ）的活性降低,但叶的 Ｇ Ｓ活性对 Ｎａ Ｃｌ浓度的敏感性大于根根和叶中的 Ｇ Ｓ活性变化与根和叶的平均质量和可溶性蛋白水平的变化是一致的 Ｎａｔｉｖｅ Ｐ Ａ Ｇ Ｅ活性染色以及 Ｉｍ ｍ ｕｎｏｂｌｏｔｔｉｎｇ 检测表明,根和叶的 Ｇ Ｓ活性的降低主要是由于 Ｇ Ｓｒｂ 和 Ｇ Ｓ２的活性及其相应蛋白质水平降低所致     

谷氨酰胺,运动与免疫

论述了有关谷氨酰胺，运动与免疫之间的关系及其变化机制，认为免疫细胞对谷氨酰胺有很高的利用率，而且谷氨酰胺对免疫细胞正常功能的维持也有非常重要的作用。长时间耐力运动可能降低骨骼肌和血浆谷氨酰胺的含量，进而损害免疫系统的功能。     

Anti-Fatigue Peptides from the Enzymatic Hydrolysates of Cervus elaphus Blood

Red deer (Cervus elaphus) blood is widely used as a health product. Mixed culture fermentation improves the flavor and bioavailability of deer blood (DB), and both DB and its enzymatic hydrolysates exhibit anti-fatigue activities in vivo. To elucidate the bioactive ingredients, enzymatic hydrolysates were fractioned into different peptide groups using reversed phase resin chromatography, and then evaluated using an exhaustive swimming mice model to assess swimming time and biochemical parameters. The structures of the bioactive peptides were elucidated by high performance liquid chromatography with tandem mass detection. Thirty-one compounds were identified as glutamine or branched-chain amino acids containing short peptides, of which Val-Ala-Asn, Val-Val-Ser-Ala, Leu(Ile)-Leu(Ile)-Val-Thr, Pro-His-Pro-Thr-Thr, Glu-Val-Ala-Phe and Val-Leu(Ile)-Asp-Ala-Phe are new peptides. The fractions containing glutamine or valine short peptides, Ala-Gln, Val-Gln, Val-Val-Ser-Ala, Val-Leu(Ile)-Ser improved exercise endurance by increasing hepatic glycogen (HG) storage. The peptides group containing Leu(Ile)-Leu(Ile), Asp-Gln, Phe- Leu(Ile), Val-Val-Tyr-Pro contributed to decreased muscle lactic acid (MLA)accumulation and to an increase in HG. The anti-fatigue activities of DB hydrolysates were attributed to the synergistic effects of different types of peptides.     

5-氟尿嘧啶-聚[N-(2-羟乙基)-L-谷酰胺]的合成及缓释性能研究

以聚谷氨酸苄酯为原料,用乙醇胺进行胺解得水溶性的可生物降解的聚[N-(2-羟乙基)-L-谷酰胺];用光气/甲苯液活化5-氟尿嘧啶,将其以共价键形式键合在高分子上,得5-氟尿嘧啶的高分子前药。用IR、UV、1HNMR及DSC对其结构进行表征,用紫外光谱测定其药物含量,载药高分子的接药率约为38.4%,高分子前药在pH=7.2的磷酸盐介质中42天内的药物累积释放量为57.53%。实验结果表明,5-氟尿嘧啶以共价键的形式键合在聚[N-(2-羟乙基)-L-谷酰胺]之上,在体外有明显的缓释效果。     

Effect of exogenous ammonium on glutamine synthetase, glutamate synthase, and glutamate dehydrogenase in the root of rice seedling

Root biomass of rice seedlings was increased at lower concentration of exogenous NH ₄ ⁺ , but it was decreased at higher concentration of exogenous NH ₄ ⁺ . The level of free NH ₄ ⁺ in the roots was accumulated gradually with the increase of NH ₄ ⁺ concentration in the nutrient solution. The content of the soluble proteins was essentially constant at higher NH ₄ ⁺ . The activities of glutamine synthetase (GS), NADH-dependent glutamate synthase (NADH-GOGAT), and NADH-dependent glutamate dehydrogenase (NADH-GDH) were risen with exogenous NH ₄ ⁺ concentration at the lower NH ₄ ⁺ concentration range. But the activities of GS and NADH-GOGAT were declined, and the level of NADH-GDH activity was kept constant under higher NH ₄ ⁺ concentration. The GS/GDH ratio suggested that NH ₄ ⁺ was assimilated by GS-GOGAT cycle under lower NH ₄ ⁺ concentration, but NADH-GDH was more important for NH ₄ ⁺ assimilation and detoxifying NH ₄ ⁺ to the tissue cells at the higher NH ₄ ⁺ level. According to the growth and the activity changes of these ammonium-assimilating enzymes of rice seedling roots, 10. 0 μg/mL NH ₄ ⁺ -N in nutrient solution was more suitable to the rice growth. Foundation item: Supported by the National Natural Science Foundation of China (No. 3987052), Natural Science Foundation of Hubei Province and International Rice Research Institute, P.O. Box. 3217, 1271 Makati City, Philippines. Biography: LI Ze-song(1968-), male, Graduate student.     

反相高效液相色谱法快速测定谷氨酰胺发酵过程中主要游离氨基酸

谷氨酸胺发酵过程代谢的主要游离氨基酸是谷氨酸胺和谷氨酸．用反相高效液相色谱技术,采用柱前衍生、荧光检测的方法可快速测定其含量．本法衍生步骤简单、灵敏度高、选择性强．利用该技术对正常谷氨酸胺发酵过程代谢的两种主要氨基酸含量变化进行了分析,为谷氨酸胺发酵过程分析提供了可靠的依据．     

固氮鱼腥藻HB686固氮_放氢与谷氨酰胺合成酶的关系

固氮鱼腥藻HB686(Anabaena azotica HB686)的固氮和放氢被氨抑制与蛋氨酸砜亚胺(MSX)解除氨抑制的作用呈平行关系.谷氨酰胺能抑制固氮和放氢,而对谷氨酰胺合成酶(GS)和吸氢酶却有激活作用.固氮血腥藻在Mg~(2+)介质中的乙炔还原活性和放氢量皆比在Mn~(2+)介质中的高,而GS的活性则相反.不同波长的光照射对固氮、放氢和GS活性有不同的影响.     

NMR metabolic profiling of organic and aqueous sea bass extracts: implications in the discrimination of wild and cultured sea bass

The nuclear magnetic resonance (NMR) technique was used as analytical tool to determine the complete metabolic profiling of sea bass extracts: water-soluble metabolites belonging to different classes such as sugars, amino acids, dipeptides and organic acids as well as metabolites soluble in organic solvent such as lipids, sterols and fatty acids were identified. The metabolite profiling together with a suitable statistical analysis were used to discriminate between wild and cultured sea bass samples. Preliminary results show that discrimination between wild and cultured sea bass was obtained not only using fatty acid composition but also cholesterol and phosphatidylethanolamine and some water-soluble metabolites such as choline, trimethylamine oxide, glutamine, fumaric and malic acids.