基于成串刺激计算立即释放囊泡池（RRP）大小的改进方法

突触囊泡的立即释放囊泡池（RRP）概念已被广泛用于突触传递的分析. 基于这些囊泡池中囊泡性质是均匀的假设，通过外推成串刺激累积诱发的突触后兴奋性电流，已经开发了几种确定RRP大小的方法. 然而，使用不同刺激频率确定这些成串刺激得到的RRP大小结果不同. 这种频率依赖性显示了这些估算方法的不完备性，与RRP的定义相矛盾. 因此，我们提出了基于成串刺激计算RRP大小的改进算法. 假设RRP的填充率正比于RRP释放的部分，并且矫正RRP的未使用部分，给出RRP释放过程的完整数学描述，得到具体的解析结果. 与已知的两种常用方法做比较，该方法很好地描述了RRP的释放和填充过程，得到了比较良好的RRP大小和囊泡释放概率大小的评估. 该方法不受刺激频率的条件限制，可以很好地适用于不能给予高频刺激的细胞.     

一种经济、简便和准确鉴定重组质粒的方法

目的：提高重组质粒的筛选效率,探讨一种经济、快速并准确的重组质粒鉴定方法。方法：取200μl菌液于Eppendorf管中高速离心1min,倒出上清,沉淀中加入20μl裂解缓冲液以裂解细胞并释放出内部质粒,10000r/min离心10min后取5～10μl上清液进行琼脂糖凝胶电泳,并比较其迁移位置来以判断重组质粒。结果：该方法鉴定结果和PCR鉴定结果完全一致。结论：该方法具有成本低廉、简便快速的特点,在对大量样品进行鉴定时具明显优势,适合在常规实验室推广。     

组氨酸生产中间控制方法的研究

研究了组氨酸与Pauly试剂显色反应的适宜条件 ,并加入钠盐和酪氨酸对标准曲线进行校正后 ,作为组氨酸定量测定的工作曲线。该方法简便 ,快速 ,准确度高 ,重现性好     

An Improved Method for Chromosome Counting in Maize

An improved method for counting chromosomes in maize (Zea mays L.) is presented. Application of cold treatment (5C, 24 hr), heat treatment (42 C, 5 min) and a second cold treatment (5C, 24 hr) to root tips before fixation increased the number of condensed and dispersed countable metaphase chromosome figures. Fixed root tips were prepared by the enzymatic maceration-air drying method and preparations were stained with acetic orcein. Under favorable conditions, one preparation with 50-100 countable chromosome figures could be obtained in diploid maize using this method. Conditions affecting the dispersion of the chromosomes are described. This technique is especially useful for determining the somatic chromosome number in triploid and tetraploid maize lines.     

Improved Plasmids for Fluorescent Protein Tagging of Microtubules in Saccharomyces cerevisiae

The ability to fluorescently label microtubules in live cells has enabled numerous studies of motile and mitotic processes. Such studies are particularly useful in budding yeast owing to the ease with which they can be genetically manipulated and imaged by live cell fluorescence microscopy. Because of problems associated with fusing genes encoding fluorescent proteins (FPs) to the native α‐tubulin (TUB1) gene, the FP‐Tub1 fusion is generally integrated into the genome such that the endogenous TUB1 locus is left intact. Although such modifications have no apparent consequences on cell viability, it is unknown if these genome‐integrated FP‐tubulin fusions negatively affect microtubule functions. Thus, a simple, economical and highly sensitive assay of microtubule function is required. Furthermore, the current plasmids available for generation of FP‐Tub1 fusions have not kept pace with the development of improved FPs. Here, we have developed a simple and sensitive assay of microtubule function that is sufficient to identify microtubule defects that were not apparent by fluorescence microscopy or cell growth assays. Using results obtained from this assay, we have engineered a new family of 30 FP‐Tub1 plasmids that use various improved FPs and numerous selectable markers that upon genome integration have no apparent defect on microtubule function.      

An Improved Method for Standardization of Microspectrofluorometers

The use of meshed cadmium-zinc sulfide fluorescent particles in combination with an electron microscope locator grid greatly facilitates the standardization of miam spectrofluorometers. The fluorescent particles emit maximally at 570 nm, and the intensity of fluorescence is directly proportional to cross-sectional area when epi-illumination is used Details concerning technique and fluorescent particle characteristics are reported.     

An Improved Method for Estimating Macromolecular Synthesis

Estimating rates of DNA, RNA, and protein synthesis has beengreatly facilitated by the use of radioactive precursors. Currentlyavailable methods to assess macromolecular synthesis in higherplants are time-consuming and imprecise. In the procedure outlinedhere, the conventional method is simplified by processing thetissue intact. This method allows a rapid analysis and considerablyreduces the inherent variability associated with the conventionalmethod.     

An Improved Method for Embedding Brain Tissue in Albumin-Gelatin

A new modification of the Snodgrass-Dorsey (1963) albumin embedding method is described. Formalin fixed brains of various ages of rhesus monkey (Macaca mulatta) were sunk in 10% phosphate buffered formalin which contained 30% sucrose. and then embedded in a 3% gelatin, 30% egg albumin solution which had been centrifuged to ensure uniformity. The albumin-gelatin was hardened in formaldehyde fumes and blocks cut frozen at 10-40 μm. Sections thus prepared can be handled easily and mounted without damage to the tissue. Modifications of conventional cell and fiber stains produce high quality finished slides in which the stained brain tissue is surrounded by a colorless albumin-gelatin matrix.     

An Innovative Method for Exosome Quantification and Size Measurement

Although the biological importance of exosomes has recently gained an increasing amount of scientific and clinical attention, much is still unknown about their complex pathways, their bioavailability and their diverse functions in health and disease. Current work focuses on the presence and the behavior of exosomes (in vitro as well as in vivo) in the context of different human disorders, especially in the fields of oncology, gynecology and cardiology.Unfortunately, neither a consensus regarding a gold standard for exosome isolation exists, nor is there an agreement on such a method for their quantitative analysis. As there are many methods for the purification of exosomes and also many possibilities for their quantitative and qualitative analysis, it is difficult to determine a combination of methods for the ideal approach. Here, we demonstrate nanoparticle tracking analysis (NTA), a semi-automated method for the characterization of exosomes after isolation from human plasma by ultracentrifugation. The presented results show that this approach for isolation, as well as the determination of the average number and size of exosomes, delivers reproducible and valid data, as confirmed by other methods, such as scanning electron microscopy (SEM).     

An Improved Method for Identifying 8-O-Acetyl-N-Acetylneuraminic Acid

The periodic acid/thionin-Schiff/potassium hydroxide/periodic acid/fuchsin-Schiff sequence developed by Culling et al. frequently causes damage to sections and gives inconsistent results because of insufficient primary oxidation and difficulties in making the thionin-Schiff reagent. These disadvantages have been largely eliminated by more thorough primary oxidation and by replacing the original thionin-Schiff with a new cold thionin-Schiff. The effect of alkaline hydrolysis on thionin-aldehyde complexes was also studied and the reduction of color caused by this treatment was restored by a second thionin-Schiff reaction. The new sequence gives consistent results and imparts greater color to the thionin-Schiff reaction.     

An Improved Method for Determining Lipolytic Acyl-hydrolase Activity

The effects of 2-phthalimidooxyalkanoic acid derivatives on the germination and root-growth of cress were examined. Since 2-phthalimidooxypropionates were most effective, the optically active ethyl esters were prepared. As the result of biological testing, the (S)-(-)-isomer exhibited stronger activity than the (R)-(+)-isomer. This result is contrary to those from commercial herbicides with similar structures, phenoxy- and oxyphenoxy-propionate-type compounds, where the (R)-isomers are generally known to be the active principles.     

An Improved Parameter Estimation Method for Hodgkin-Huxley Models

We consider whole-cell voltage-clamp data of isolated currents characterized by the Hodgkin-Huxley paradigm. We examine the errors associated with the typical parameter estimation method for these data and show them to be unsatisfactorally large especially if the time constants of activation and inactivation are not sufficiently separated. The size of these errors is due to the fact that the steady-state and kinetic properties of the current are estimated disjointly. We present an improved parameter estimation method that utilizes all of the information in the voltage-clamp conductance data to estimate steady-state and kinetic properties simultaneously and illustrate its success compared to the standard method using simulated data and data from P. interruptus shal channels expressed in oocytes.     

An Improved Method for the Synthesis of Flavanones

An isomerization of 2"-hydroxychalcones into the corresponding flavanones in ethanol in the presence of triethylamine is described.     

An Improved Method for Marine Cyanobacterial DNA Isolation

Summary The method of Bolch, Blackburn, Jones, Orr & Grewe [Phycologia, 36, 6 11, 1997] developed for isolation of DNA from freshwater cyanobacteria was suitably modified to yield a simple, efficient and reproducible protocol for the isolation of DNA from different morphological types of marine cyanobacteria. This method resulted in a high yield of quality DNA suitable for polymerase chain reaction (PCR) amplifications.     

An Improved Method for Studying Grass Leaf Epidermis

Leaf epidermis of grasses is elaborate and important in the systematica of the Poaceae at subfamily and genus level. Most available techniques used in preparing leaf epidermis for microscopic studies are time-consuming and often produce preparations inadequate for studying histological detail. A combination of the hand scraping and maceration methods with modifications is proposed in this paper to prepare epidermal peels comparatively rapidly. One epidermal layer was scraped off and the mesophyll tissue removed from the epidermis to be studied by maceration in HNO, The recovered epidermal peel was neutralized in NaOH and stained with malachite green or safranin O. Preparations made by this technique are suitable for studies of epidermal features, measurements of special structures and determinations of trichome indices. This method has been used in a study investigating intraspecific variation in southern African pasture grasses.     

一种改进的cDNA文库固相构建法

本文介绍一种新的cDNA文库固相构建法。文库构建过程中,cDNA的合成和修饰全部在固相介质――磁珠上完成,简便、迅速、文库质量高,能满足不同目的的cDNA文库构建,是一种值得借鉴和应用的好方法。 Abstract：A method for cDNA library construction was introduced.All enzymatic steps of library synthesis were performed on a solid support-magnetic beads.Therefore it combines fast speed and convenient with high quality library,making it ideally suited for most purposes.It is a good method and worth learning and utilization.     

一种改进的蛋白质超薄凝胶电泳方法

介绍了一种将聚丙烯酰胺凝胶固定在电泳夹板上的蛋白质电泳方法.通过此方法蛋白质电泳可以在0.4 mm厚的聚丙烯酰胺凝胶上进行.实验证明,经此方法处理的玻板结合凝胶非常牢固,在电泳后的所有处理步骤中都不会发生凝胶脱落现象.