结核分枝杆菌H37Rv组氨醇脱氢酶基因的克隆、表达及酶学性质分析

以结核分枝杆菌H37Rv基因组为模板,扩增hisD基因,构建pET-28a-HDH重组质粒;转化重组质粒到E.coli BL21(DE3)并诱导表达,纯化可溶性的结核分枝杆菌L-组氨醇脱氢酶(HDH),并对其性质进行研究,结果表明:重组结核分枝杆菌L-组氨醇脱氢酶能以L-组氨醇和NAD 为底物催化L-组氨醇生成L-组氨酸;该酶的最适pH值为8.3,最适温度为45℃,比活力为1.788 U/mg;Mn2 ,Ca2 ,Zn2 ,Co2 等对酶促反应有激活作用;底物NAD 和L-组氨醇的米氏常数分别为0.9765 mmol/L和2.755μmol/L;25℃时重组蛋白的二级结构中有20.5%的α-螺旋,40.9%β-折叠,4.2%β-转角,34.3%无规卷曲.     

Cr2O3／SiC（M,Y）—Al2O3系稳定的低粘度高固相含量悬浮体的制备

研究了复相 Cr2 O3 / Si C(M,Y) - Al2 O3 系稳定的高固相含量的低粘度悬浮体的流变特性 ,找出了影响流变性的主要因素。在碱性条件下 ,用实验室合成的 PMAA- NH4和 CM作为复合分散剂以及引入有机单体制备出固相含量高达 6 3(vol) % ,粘度为 2 35 m Pa.s的 Cr2 O3 /Si C(M,Y) - Al2 O3 悬浮体。     

The effects of beta-endorphin on arginine-8-vasopressin and oxytocin levels in rat brain areas

Summary Measurements were made of the effects of intracerebroventricular treatment with beta-endorphin (BE; 100 ng) on the arginine-8-vasopressin (AVP) and oxytocin contents of rat hypothalamic and limbic brain areas (hippocampus, amygdala and septum). The hormone concentrations were determined by radioimmunoassay. The administration of BE resulted in a significant reduction of the AVP level in the amygdala in a naloxone-reversible manner. Naloxone (Nal) administered subcutaneously significantly increased the AVP content in the septum. The results revealed that BE and Nal had regionally specific effects on the activity of the vasopressinergic system but not on that of the oxytocinergic system in the brain.     

Volatile organic compounds sensing based on Bennet doubler-inspired triboelectric nanogenerator and machine learning-assisted ion mobility analysis

Ion mobility analysis is a well-known analytical technique for identifying gas-phase compounds in fast-response gas-monitoring systems.However,the conventional ...     

The Liar-paradox in a Quantum Mechanical Perspective

In this paper we concentrate on the nature of the liar paradox asa cognitive entity; a consistently testable configuration of properties. We elaborate further on a quantum mechanical model (Aerts, Broekaert and Smets, 1999) that has been proposed to analyze the dynamics involved, and we focus on the interpretation and concomitant philosophical picture. Some conclusions we draw from our model favor an effective realistic interpretation of cognitive reality.     

Detailed analysis of the plasma extracellular vesicle proteome after separation from lipoproteins

The isolation of extracellular vesicles (EVs) from blood is of great importance to understand the biological role of circulating EVs and to develop EVs as biomarkers of disease. Due to the concurrent presence of lipoprotein particles, however, blood is one of the most difficult body fluids to isolate EVs from. The aim of this study was to develop a robust method to isolate and characterise EVs from blood with minimal contamination by plasma proteins and lipoprotein particles. Plasma and serum were collected from healthy subjects, and EVs were isolated by size-exclusion chromatography (SEC), with most particles being present in fractions 8–12, while the bulk of the plasma proteins was present in fractions 11–28. Vesicle markers peaked in fractions 7–11; however, the same fractions also contained lipoprotein particles. The purity of EVs was improved by combining a density cushion with SEC to further separate lipoprotein particles from the vesicles, which reduced the contamination of lipoprotein particles by 100-fold. Using this novel isolation procedure, a total of 1187 proteins were identified in plasma EVs by mass spectrometry, of which several proteins are known as EV-associated proteins but have hitherto not been identified in the previous proteomic studies of plasma EVs. This study shows that SEC alone is unable to completely separate plasma EVs from lipoprotein particles. However, combining SEC with a density cushion significantly improved the separation of EVs from lipoproteins and allowed for a detailed analysis of the proteome of plasma EVs, thus making blood a viable source for EV biomarker discovery.     

Twisting the Dollar? On the Consistency of Short‐Run and Long‐Run Exchange Rate Expectations

We examine consistency properties of the exchange rate expectation formation process of short‐run and long‐run forecasts in the dollar/euro and yen/dollar market. Applying nonlinear consistency restrictions we show that in a simple expectation formation structure short‐run forecasts are indeed inconsistent with long‐run predictions. Moreover, we establish a ‘twist’ in the dollar/euro expectation formation process, i.e. market participants expect bandwagon effects in the short run, while they have stabilizing expectations in their long‐run forecasts. Applying a panel probit analysis we find that this twisting behavior is more likely to occur in periods of excess exchange rate volatility. Copyright © 2011 John Wiley & Sons, Ltd.