脑内微透析采样技术及其在神经科学中的应用

作为一种新的在体化学采样技术,脑内微透析引起了神经科学家的关注。它与迅速发展起来的高灵敏度的微量分析技术相结合,实现了对体内细胞外环境中化学物质变化的动态监测,从而在神经科学领域获得应用。本系统地介绍了这一新技术的原理和方法,并扼要地介绍了一这一技术在神经科学中的应用及其取得的新进展,并结合本实验室的工作经验,对该技术存在的一些问题进行了讨论。     

A new method for the determination of critical polyethylene glycol concentration for selective precipitation of DNA fragments

Separation strategies based on size-selective precipitation of DNA fragments with polyethylene glycol (PEG) have been used for achieving desired DNA interval in automated sample preparation for next-generation sequencing. By varying PEG concentration, DNA fragments of different sizes can be precipitated onto surfaces of carboxyl-coated paramagnetic particles selectively, and therefore, the desired DNA interval can be obtained. However, one of the crucial points in this approach is to determine the critical PEG concentration for DNA fragment of a certain size. The aim of this work was to develop a convenient and reliable method for accurately determining the critical PEG concentration. In our method, at a fixed concentration of sodium chloride (NaCl), recovered DNA samples obtained with different PEG concentrations were directly quantified, and their concentrations as a function of the PEG concentration were fitted by the logistic function. The critical PEG value was easily and accurately determined from the fitted logistic function. The repeatability and stability of the critical PEG value were assessed, showing an excellent reliability of the method. Based on this method, critical PEG values of different-size DNA fragments were determined at different NaCl concentrations. The effectiveness of the method was also demonstrated by selective precipitation of DNA fragments.     

Purification and properties of alkaline phosphatase of silkworm Bombyx mori

Alkaline phosphatase(AKP),from the succus entericus of silkworm,was purified using 10%-50% ammonium sulfate fractions,ion exchange chromatography Of DEAE-Sepharose,and size exclusion chromatography of Sephacryl S-200.The purification fold was 464 times and specified activity was 3936 U/mg.Optimum pH value of the phosphatase was 10.5,and was stable between pH 7.5 and 11.The optimum temperature of the phosphatase was 40℃ and it was unstable over 50℃.Km value of the phosphatase was 1.25 mmol/L.In a given condition,the phosphatase was selectively modified by PCMB,NBS,PMSE TNBS,SUAN,DTT,BrAc,and IAc,the results indicate that PMSF,SUA,BrAc,IAc,and TNBS could Obviously inhibit the activity of the phosphatase,and the degree of inhibition depended on the concentration of these reagents.There was little effect on the activity of phosphatase after treatment by PMSF,DTT,and NBT.We primarily conclude that mercapto and imidazole are essential for AKP from silkworm.Also,Lys residue and disulfide bands are necessary to protect the catalysis of the AKP.     

Enhanced production of (+)-terrein in fed-batch cultivation of Aspergillus terreus strain PF26 with sodium citrate

(+)-Terrein is a fungal metabolite with multiple biological activities, especially with great value in medicine. However, the mass production of single configuration terrein is still a big challenge. In this study, the effects of acetic acid, sodium acetate, citric acid and sodium citrate on the (+)-terrein production by Aspergillus terreus strain PF26 derived from marine sponge Phakellia fusca were investigated. Sodium citrate was selected for fed-batch cultivation because it showed the best effect on (+)-terrein production among the four regulators tested. As a result, 5.38 g/L (+)-terrein production was achieved by feeding 10 mM sodium citrate on the 3rd day in shake flask, which was 33.8 % higher than the control and represented the highest yield of (+)-terrein. In a 7.5-L stirred bioreactor, 2.58 g/L of (+)-terrein production was achieved by the feeding of 10 mM sodium citrate on the 8th day. The results from this study lay a basis for the high-yield production of (+)-terrein by fermentation.     

不同萃取体系对小球藻藻渣成分的影响

考察5种萃取体系（A：正己烷,B：正己烷/乙醇,C：正己烷/异丙醇,D：氯仿/甲醇,E：氯仿/乙醇）对小球藻（Chlorella phyrenoidosa）油脂的提取效果及藻渣成分的影响。实验结果表明：不同的萃取体系下,油脂得率为D（12.27%）、E（8.87%）、C（7.71%）、B（6.80%）、A（3.91%）,藻渣蛋白含量为A（52.60%）、E（46.23%）、B（40.19%）、C（39.52%）、D（32.52%）,藻渣碳水化合物含量为A（23.28%）、E（16.15%）、B（13.24%）、D（13.50%）、C（9.06%）;藻渣色素含量为A（1.75%）、E（1.29%）、B（1.14%）、C（0.96%）、D（0.58%）;藻渣灰分含量为D（3.63%）、E（2.94%）、C（2.23%）、B（2.25%）、A（1.48%）。综合考虑微藻生物柴油的生产及藻渣的可利用性,V（氯仿）/V（乙醇）=1是一种油脂萃取效果较好,藻渣营养成分损失较小的小球藻油脂萃取体系。     

2009年徽州稻区白背飞虱种群消长及虫源性质

徽州稻区作为我国白背飞虱北迁与南迁的重要中转站之一,地理位置十分特殊,分析其中、晚稻田白背飞虱种群动态及虫源性质,对皖南稻区乃至江淮稻区白背飞虱预测预报和防治工作意义重大。通过田间系统调查和长翅雌虫卵巢解剖,研究了徽州稻区白背飞虱种群消长及虫源性质。运用GrADS和ArcGIS分析2009年白背飞虱主要迁入期的天气背景,并利用HYSPLIT轨迹模拟平台对主要迁入期进行数值模拟和虫源地分析。结果表明:2009年徽州稻区白背飞虱在中、晚稻以第3代危害为主。中稻田第2—4代白背飞虱属于基本迁出型,同时第3代前半期还存在部分滞留本地繁殖或者是外地白背飞虱迁入现象;而晚稻第3代后半期白背飞虱属于基本迁入型,第4—5代属于基本迁出型。风切变、下沉气流和强降水可作为徽州稻区预测白背飞虱迁入的气象背景。2009年徽州稻区白背飞虱虫源地主要分布在湘南、赣中及赣南。     

植物防御反应中活性氧的产生和作用

活性氧在植物抗病性中起着重要的作用。本文将对其在防御反应中的产生和作用进行简要的论述。     

芦荟苷A、B以及异芦荟色苷D的同时分离纯化

首次采用反相中压制备色谱从芦荟中一次分离制备得到芦荟苷A、B以及异芦荟色苷D。以库拉索芦荟丙酮粗提物为原料,采用中压制备色谱系统:SCO色谱柱(40 cm×26 cm,30～50μm),流动相甲醇-0.5%乙酸水(33∶67,V/V),流速20 mL/min,等度洗脱方式,柱温室温,检测波长254 nm,收集波长356 nm对芦荟样品进行分离制备,得到三种化合物单体。经高效液相色谱、紫外、红外、质谱及核磁共振等方法分析表明所得到的三种化合物分别是异芦荟色苷D、芦荟苷A和芦荟苷B,其纯度分别达到了98.0%,96.0%和98.9%。该方法简便,产品质量高,一次制备可以得到多种单体,为芦荟成分的测定与药理活性的研究提供了条件。     

酵母表面展示脂肪酶合成己二酸二异辛酯

展示酶的酵母细胞既具有固定化酶的优点,又有制备简单、成本较低的特点.采用表面展示南极假丝酵母脂肪酶B (Candida antarctica lipase B,CALB)的毕赤酵母细胞催化合成己二酸二异辛酯(Diisooctyl adipate,DIOA),对该反应体系进行优化,并实现了初步工艺放大制备.经条件优化后,在10mL反应体系中,DIOA的产率可达85.0％.该工艺放大到200mL反应体系时,DIOA产率可达97.8％.经减压蒸馏,DIOA纯度可达到98.2％.该酵母表面展示脂肪酶在合成绿色润滑油己二酸二异辛酯中具有良好应用前景.     

Critical role of interleukin-17/interleukin-17 receptor axis in mediating Con A-induced hepatitis

Concanavalin A (Con A)-induced hepatitis is thought to be a T-cell-mediated disease with active destruction of liver cells. Interleukin (IL)-17 is a cytokine produced principally by CD4(+) T cells. However, whether IL-17/IL-17 receptor (IL-17/IL-17R)-mediated responses are involved in T-cell-mediated Con A-induced liver injury remains unclear. In this study, we found that IL-17 expression was highly elevated in liver tissues during Con A-induced hepatitis. The increased levels of IL-17 were paralleled with the severity of liver injury reflected by Alanine aminotransaminase and histological assay as well as the secretion of tumor necrosis factor (TNF)-α and IL-6. Blockage of IL-17 significantly ameliorated Con A-induced hepatitis, while overexpression of IL-17 systemically resulted in massive hepatocyte necrosis in mice. Furthermore, overexpression of an IL-17R immunoglobulin G1 fusion protein significantly attenuated liver inflammation after acute Con A treatment. High expression of IL-17R on Kupffer cells was also observed along with the production of cytokines including TNF-α and IL-6. Inhibition of Kupffer cells by gadolinium chloride completely prevented Con A-induced liver injury and cytokine release. Finally, IL-17-expressing CD4(+) T and natural killer T cells were greatly increased in Con A-injected mice compared with that in controls. Overall, our results indicate that IL-17R signaling is critically involved in the pathogenesis in Con A-induced hepatitis, and blockade of IL-17/IL-17R signaling pathway may represent a novel therapeutic intervention in human autoimmune-related hepatitis.