甜瓜子叶发育过程中蛋白质水平和氨同化酶活性变化

测定了甜瓜种子萌发和子叶发育过程中谷氨酰胺合成酶(GS)、依赖于NADH的谷氨酸合酶(NADH-GOGAT)、依赖于NADH的谷氨酸脱氢酶(NADH-GDH)等酶的活性变化以及种子萌发时可溶性蛋白水平的变化．在有氮或无氮下，在子叶刚出土时GS和NADH-GOGAT活性较低，随着子叶的发育，这两种酶的活性升高，两者分别于第7天和第5天达到最高，其后活性逐步降低．但是NADH-GDH呈现出相反的变化，在子叶发育的前期阶段其活性低，而后逐步升高．可溶性蛋白的含量随着子叶的发育而逐步降低．外源氮的加入对蛋白质水平和酶的活性具有小的正面影响．     

Concise and Efficient Synthesis of Highly Potent and Selective Dipeptidyl Peptidase II Inhibitors

Highly potent and selective DPP II inhibitors N′‐(4‐Chlorobenzyl)‐N′‐methyl‐4‐oxo‐4‐(1‐piperidinyl)‐1,3‐(S)‐butane‐diamine dihydrochloride 1 and N′‐(4‐chlorobenzyl)‐4‐oxo‐4‐(1‐piperidinyl)‐1,3‐(S)‐butanediamine dihydrochloride 2 have been efficiently synthesized starting from L‐glutamine. A short and high yielding route with simple isolation techniques has been disclosed.     

益生菌联合谷氨酰胺的肠内营养对重症急性胰腺炎肠黏膜屏障恢复的作用

目的研究了益生菌联合谷氨酰胺的肠内营养治疗对恢复重症急性胰腺炎（SAP）的肠道屏障功能的作用。方法将74例重症急性胰腺炎患者随机分为3组：常规肠内营养组（EN组）,肠内营养＋谷氨酰胺组（Gln组）,肠内营养＋谷氨酰胺＋益生菌制剂组（益生菌组）。治疗第1、7、14、21天进行APACHEⅡ评分,并取血测定血清中的谷氨酰胺、内毒素、CRP、D-乳酸水平。结果三组病人APACHE11评分、CRP均逐渐下降,在第7天,Gln组和益生菌组CRP水平下降,并且与EN组对比,差异有统计学意义,而益生菌组和Gln组在第14天的APACHEⅡ评分与EN组差异有统计学意义。三组患者血清Gln浓度在第7天测定均成不同程度下降,Gln组与益生菌组分别与EN组比较,差异无统计学意义。在第14天,三组Gln水平均上升,益生菌组与EN组对比,差异有统计学意义（P〈0.05）。在第7天,益生菌组的血清内毒素、D-乳酸水平低于EN组,差异有统计学意义。在第14天,Gln组和益生菌组的内毒素水平和D-乳酸水平均低于EN组,差异有统计学意义,益生菌组的DAO水平低于EN组,差异有统计学意义（P〈0.05）。结论应用益生菌制剂和Gln的肠内营养能更好地维护肠道黏膜屏障的完整,应用前景广阔。但益生菌制剂和Gln免疫制剂问的协同作用需要进一步论证。     

谷氨酰胺对运动机体的影响

谷氨酰胺是人体内重要的氨基酸，与运动能力有密切的联系。机体运动对谷氨酰胺代谢的影响与运动持续时间、运动强度、运动方式等因素有关，短时间运动能使血浆谷氨酰胺浓度升高，长时间耐力运动则使之含量下降。长时间耐力性运动导致的血浆谷氨酰胺含量的降低可能引起耐力运动中蛋白质分解代谢失常、氨转运清除率下降以及运动后机体免疫功能下降等。     

L-谷氨酰胺生产菌的定向选育及其发酵条件的初步研究

以TG - 86 6 (BrevibacteriumTianjin)为出发菌株 ,利用硫酸二乙酯 (DES)诱变 ,定向选育出一株谷氨酰胺生产菌GMS - 44(MSOr、(NH4 ) 2 SO4 r、SGr) ,在适宜的条件下平均积累谷氨酰胺 2 7 0 g/L。并对种子培养基及发酵培养基配方作了优化设计。     

不同浓度不同氮源对小麦离体叶谷氨酰胺合成酶及其相关酶的影响

利用酶活测定和Northern分子杂变等技术，研究了小麦幼苗离体叶片在不同浓度的不同氮源供应下，其谷氨酰胺合成酶(Gs)、天冬酰胺合成酶(As)、硝酸还原酶(NR)以及Gs基因在转录水平GS-mRNA的变化．结果表明：NH 4处理的小麦，其叶部GS活性比N0f处理的高，NortherⅡ杂交结果说明GS-mRNA转录量与GS活性一致；NO-3可激活NR活性，对AS有较明显的诱导作用．     

High-density hybridoma perfusion culture

Because our earlier work indicated a strong correlation between specific antibody productivity and cell density in perfusion culture, we conducted experiments to determine the optimum means of increasing cell density while mainitaining high antibody productivity. The rates of medium supply and waste removal were varied to determine whether cell density was limited or inhibited, and whether a diffusable substance could be responsible for the correlation between antibody productivity and cell density. Nutrient supply was found to be a stronger determinant of cell density than waste removal; however, the rate of waste removal had a greater effect on cell growth at lower cell densities. Even at noninhibitory levels of ammonia and lactate, cellular metabolism was regulated to minimize their concentrations at lowered rates of waste removal. Separate step changes in glucose and glutamine resulted in increased cell density and antibody concentration. Specific antibody productivity increased following the step in glutamine, but not glucose. Both steps caused changes in cellular metabolism that prevented the levels of lactate and ammonia from reaching toxic levels.     

The effect of alternative carbohydrates on the growth and antibody production of a murine hybridoma

A murine hybridoma (CC9C10) was adapted to grow in media containing alternative carbohydrates to glucose. Cell yields relative to the glucose-based culture decreased in order of the following supplements: glucose = maltose > galactose > fructose = sorbitol = xylitol, although significant yields (> 50% of glucose control) were observed in all cultures. In the absence of glucose, glutamine consumption rates were enhanced significantly. Antibody production was directly related to the viable cell concentration in each culture and was independent of the phase of culture. A high specific antibody productivity (qMab) was observed in the cultures containing the polyols, sorbitol, or xylitol, even though the cell yields and growth rates were lower than the glucose-based control. The measured qMab in the xylitol culture was 5.6x that of the glucose culture and the volumetric yield of MAb was 29% higher.     

葡萄糖和谷氨酰胺浓度对杂交瘤细胞生长代谢的影响

在生物反应器的批培养过程中考察了葡萄糖及谷氨酰胺浓度对杂交瘤细胞生长及代谢的影响。当葡萄糖浓度降至1～4mmol／L，谷氨酰胺浓度降至0．4～2mmol／L时，细胞生长并未受到明显影响，但细胞代谢途径发生转换，乳酸及氨的生成显著减少。葡萄糖和谷氨酰胺浓度的比例对杂交瘤细胞的生长及代谢也有影响，葡萄糖相对较多时，其细胞得率小，乳酸得率大；而当谷氨酰胺相对较多时，其细胞得率小，氨得率大。实验结果表明谷氨酰胺与葡萄糖的能量代谢在某种程度上可进行相互补充。