Free D- and L-amino acids in ventricular cerebrospinal fluid from Alzheimer and normal subjects

Summary Free D-Ser, D-Asp and total D-amino acids were significantly higher (p < 0.05) in Alzheimer (AD) ventricular CSF than in normal CSF. There was no significant difference in the total L-amino acids between AD and normal CSF, but L-Gln and L-His were significantly higher (p < 0.05) in ADCSF. The higher concentrations of these D- and L-amino acids in AD ventricular CSF could reflect the degenerative process that occurs in Alzheimer's brain since ventricular CSF is the repository of amino acids from the brain.     

黄单胞杆菌XC—82,R5二步发酵工艺研究

通过对黄单胞杆菌ＸＣ－８２,Ｒ５株的黄原胶二步发酵工艺研究,针对菌株在生长时期与产胶时期不同培养条件的需求,确定了两个阶段各自适宜的培养基组成,温度,ｐＨ值条件,实验表明,当流加稀释率为５时,二步发酵生产可达到了较高水平,其产胶量较传统的间歇发酵提高３１％。     

双CSTR耦合系统中乙醇发酵过程中的分岔研究

本文首次运用现代分岔理论方法,研究了双CSTR耦合系统中乙醇发酵过程中的多定态和振荡现象．计算结果表明,当入口糖浓度大于某值时,多定态普遍存在．同时振荡受到底物浓度S_0、两耦合反应器的体积比V_(12)及稀释率D的影响.同单CSTR相比,双CSTR加强了反应深度,并通过适当改变V_(12),产率可大大提高.     

Cytoskeletal scaffolding proteins interact with Lynch‐Syndrome associated mismatch repair protein MLH1

The involvement of MLH1 in several mismatch repair‐independent cellular processes has been reported. In an attempt to gain further insight into the protein's cellular functions, we screened for novel interacting partners of MLH1 utilizing a bacterial two‐hybrid system. Numerous unknown interacting proteins were identified, suggesting novel biological roles of MLH1. The network of MLH1 and its partner proteins involves a multitude of cellular processes. Integration of our data with the “General Repository for Interaction Datasets” highlighted that MLH1 exhibits relationships to three interacting pairs of proteins involved in cytoskeletal and filament organization: Thymosin β 4 and Actin γ, Cathepsin B and Annexin A2 as well as Spectrin α and Desmin. Coimmunoprecipitation and colocalization experiments validated the interaction of MLH1 with these proteins. Differential mRNA levels of many of the identified proteins, detected by microarray analysis comparing MLH1‐deficient and ‐proficient cell lines, support the assumed interplay of MLH1 and the identified candidate proteins. By siRNA knock down of MLH1, we demonstrated the functional impact of MLH1–Actin interaction on filament organization and propose that dysregulation of MLH1 plays an essential role in cytoskeleton dynamics. Our data suggest novel roles of MLH1 in cellular organization and colorectal cancerogenesis.     

Atorvastatin modifies the protein profile of circulating human monocytes after an acute coronary syndrome

Aggressive treatment with high‐dose atorvastatin reduces more effectively the incidence of cardiovascular events than moderate statin therapy. The mechanism of this benefit has not been fully elucidated. In order to know the potential effects of statin treatment on the protein expression of circulating monocytes in acute coronary syndrome (ACS) patients, a proteomic analysis of these cells was carried out by 2‐DE and MS. Twenty‐five patients with non‐ST‐elevation acute coronary syndrome (NSTEACS) were randomized, the fourth day after admission, to receive ATV 80 mg/dL (n = 14) or conventional treatment (CT) (n = 11), for two months. Blood was withdrawn at the end of the treatment, and monocytes were extracted for proteomic analysis and their protein expression patterns determined. Age, sex, total cholesterol, LDL, HDL, triglycerides, body mass index, presence of hypertension, diabetes, and smoking status were not significantly different between the two groups of patients. The expression of 20 proteins was modified by intensive ATV. Among the most relevant results stand out the normalization by intensive ATV treatment of the expression of proteins that modulate inflammation and thrombosis such as protein disulfide isomerase ER60 (PDI), Annexin I, and prohibitin, or that have other protective effects as HSP‐70. Thus, this approach shed light at the molecular level of the beneficial mechanisms of anti‐atherothrombotic drugs.     

Sample size re‐estimation in clinical trials

Adaptive clinical trials are becoming very popular because of their flexibility in allowing mid‐stream changes of sample size, endpoints, populations, etc. At the same time, they have been regarded with mistrust because they can produce bizarre results in very extreme settings. Understanding the advantages and disadvantages of these rapidly developing methods is a must. This paper reviews flexible methods for sample size re‐estimation when the outcome is continuous.     

阿尔泰山两河源自然保护区森林生态系统朽木生地衣群落的数量分类

应用双向指示种分析和除趋势对应分析对阿尔泰山两河源国家级自然保护区的朽木生地衣群落进行了数量分类。初步结果表明,该自然保护区朽木生地衣共有43种,隶属于5目、14科、20属,它们组成了以下4个地衣群落。群落(Ⅰ):分布在样点1、2、3、4、5中,包括15种地衣种类,命名为对开蜈蚣衣+半羽蜈蚣衣+红心黑蜈蚣衣群落。群落(Ⅱ):分布在样点6、7、8、9、11中,包括25种地衣,命名为尖头石蕊+粉石蕊+矮石蕊群落。群落(Ⅲ):由样点10、12、13、14、16组成,常见的地衣种类有19个种,命名为蜡黄橙衣+茎口果粉衣+冷杉粉衣群落。群落(Ⅳ):包括样点15、17、18、19和20,由22个地衣种组成。命名为疑小梅衣+同色黄烛衣+脱落网衣群落。群落Ⅰ和群落Ⅱ的相似性最高为0.723,其次为群落Ⅰ和群落Ⅲ为0.609,群落Ⅲ和群落Ⅳ之间的相似性最低为0.262。群落Ⅲ的多样性最大为1.954;其次为群落Ⅱ和群落Ⅰ,分别为1.742和我1.685,群落Ⅳ的多样性最低为0.543。各群落的相似性和多样性之间的差异与其所处环境和朽木树种的多样性有关。同时发现在研究地区的朽木生地衣群落的分布与海拔高度、朽木腐蚀程度、朽木大小、森林郁闭度等因子具有密切的关系。     

Dual lifetime referencing enables pH‐control for oxidoreductions in hydrogel‐stabilized biphasic reaction systems

pH‐shifts are a serious challenge in cofactor dependent biocatalytic oxidoreductions. Therefore, a pH control strategy was developed for reaction systems, where the pH value is not directly measurable. Such a reaction system is the biphasic aqueous‐organic reaction system, where the oxidoreduction of hydrophobic substrates in organic solvents is catalysed by hydrogel‐immobilized enzymes, and enzyme‐coupled cofactor regeneration is accomplished via formate dehydrogenase, leading to a pH‐shift. Dual lifetime referencing (DLR), a fluorescence spectroscopic method, was applied for online‐monitoring of the pH‐value within the immobilizates during the reaction, allowing for a controlled dosage of formic acid. It could be shown that by applying trisodium 8‐hydroxypyrene‐1, 3, 6‐trisulfonate as pH indicator and Ru(II) tris(4, 7‐diphenyl‐1, 10‐phenantroline) (Ru[dpp]) as a reference luminophore the control of the pH‐value in a macroscopic gel‐bead‐stabilized aqueous/organic two phase system in a range of pH 6.5 to 8.0 is possible. An experimental proof of concept could maintain a stable pH of 7.5 ± 0.15 during the reaction for at least 105 h. With these results, it could be shown that DLR is a powerful tool for pH‐control within reaction systems with no direct access for conventional pH‐measurement.