Procedure for simultaneous phenotyping of genetic variants in cow's milk by isoelectric focusing*

A method is described which allows the simultaneous separation of all polymorphic protein fractions in cow's milk in one single run. The separation could be achieved by isoelectric focusing in ultrathin-layer polyacrylamide gels. The method is especially suitable for screening purposes because it combines low costs, high resolution and short separation time.     

家畜类腔前卵泡体外分离方法及其影响因素研究进展

回顾腔前卵泡体外分离方法的研究历史,着重论述牛、羊、猪等家畜的腔前卵泡体外分离方法及其影响因素,以期为建立一种更为有效的分离方法提供理论基础.     

A method of fast separation of lignin peroxidases using convective interaction media disks.

The HPLC separation of lignin peroxidase isoenzymes using Convective Interaction Media disks containing quaternary amine and diethylaminoethyl ion-exchange active groups is proposed. In contrast to standard HPLC procedures the separation can be performed within a few minutes without considerably affecting the separation resolution. The method is reproducible and gives a linear response of integrated peak area to protein concentration for all measured isoenzymes. The separation resolution is retained unchanged by applying crude culture filtrate instead of a sample previously frozen and dialyzed. The optimized method might therefore be used for on-line monitoring of lignin peroxidase isoenzyme composition during fermentation. On the other hand, the proposed method is comparable in time to the original method of lignin peroxidase activity measurement (proposed by Tien and Kirk), providing additionally the isoenzyme composition.     

Development of Dual Ensemble Monte Carlo Program and its Application to the CO2/N2 Separation

Abstract

A novel Monte Carlo simulation named as Dual Ensemble Monte Carlo (DEMC) method is developed for the investigation of the membrane separation process. In this method the spatial combination of Grand Canonical MC and Canonical MC techniques is employed. The DEMC method can be used to calculate the separation factor at a specific chemical potential gradient. At first, a check on the accuracy of the DEMC method is made by generating gas density gradient between two reservoir regions. Thereafter, we applied this method to CO₂/N₂ gas separation by inorganic membranes and calculated the separation factor dependence on the size of micropore in membranes.     

Foam separation of DNA and proteins from solutions

Foam separation on BSA-DNA (bovine serum albumine/deoxyribonucleic acid) and Lysozyme-DNA systems is performed. The separation of the total protein from DNA is evaluated for dissociated chromatin solution. Foam separation for the same systems is done also by a new method of creating a pressure gradient in the Plateau-Gibbs borders in the foam and obtaining a "dry" foam. It is shown that the effectiveness of the foam separation can be improved significantly by the application of the latter method. Some factors (pH, initial concentration of the solution, expansion factor of the foam) influencing the separation of proteins from DNA in the foam and in the residual solution are studied as well.     

On the independence of time and strain effects in the stress relaxation of ligaments and tendons

The hypothesis of variables separation, namely the time and the strain separation in the relaxation function, is widely used in soft tissue biomechanics. Although this hypothesis is central to several biomechanical models, only few experimental works have tried to verify it. From these studies, contradictory results have been found. Moreover, it has recently been noted that no such experimental verification has been performed for ligament tissues. In this paper, an experimental method is developed to test the hypothesis of variables separation. This method is then used with human cruciate ligaments and patellar tendons. It is shown that the use of the variables separation hypothesis is justified at least for strain values lower than 16% for anterior cruciate ligament, lower than 12% for posterior cruciate ligament and lower than 6% for patellar tendon. The method presented in this paper could be used to verify the validity of variables separation for other tissues.     

A new kinetic diagnostic for enzymatic mechanisms using alternative substrates

A method for the separation and quantification of the levels of alanopine and strombine in neutralized, perchloric acid extracts of tissues of marine invertebrates is presented. The method is based on high-performance liquid chromatographic (HPLC) separation, postcolumn derivatization using o-phthaldialdehyde and sodium hypochlorite, and subsequent fluorometric detection. Isocratic separation results in the rapid elution of alanopine and strombine, with elution times of 4.7 and 5.4 min, respectively. The sensitivity of this method is in the range 50-250 pmol. However, the fluorometric detection approach provides the capability for even greater sensitivity.     

膜分离技术及其在生物农药生产中的应用

膜分离技术与传统分离技术相比,具有明显的优势,常用于现代生物制药中分离、浓缩、分级与纯化蛋白质、多肽等热敏性生物药品.该文重点讨论微滤(MF)、超滤(UF)、纳滤(NF)等膜分离技术在生物农药生产中的应用.     

High-performance liquid chromatographic separation of bile acid pyrenacyl esters with cyclodextrin-containing mobile phase

The high-performance liquid chromatographic separation of bile acid pyrenacyl esters with cyclodextrin-containing mobile phase is presented. Compared with conventional methods, inclusion chromatography gives much more satisfactory separation of derivatized bile acids in a short time. The application of this method to the separation of glycine-conjugated bile acids in human bile is also described.     

水文过程的基流分割方法研究进展

基流分割研究是水文学、生态水文学研究的重点和难点之一,一直以来在其概念与方法上都缺乏统一的标准.本文详细介绍了基于不同基流组成定义的基流分割理论,并分析了各基流分割方法的发展历程.对不同分割方法进行对比发现：直接分割法简单、适用,却有任意性;水量平衡法实施起来困难,但符合水文规律;时间序列分析法和同位素法能克服手工图解分割方法的主观性和随意性,可以快速有效地得到连续基流过程.近年来,水文模拟、数字滤波、同位素法成为基流分割的主要方法.     

Protein fractionation according to molecular size in constant pH media with immobilized charges in colinear porosity gradient

A new method of protein electrophoresis is described here. Electrophoretic separation is performed in gel media with uniform concentration of immobilized charges, combined with porosity gradient directed against protein movement. Successful separation becomes possible due to the effect of strong sample zone compression; the latter effect is connected with complex conductivity profile dynamics in a gel system containing immobilized charges. Immobilized buffers combined with porosity gradient provide an opportunity of protein discrimination based on molecular size, while in the case of uniform gel concentration the separation is based on mobility differences and strongly affected by non-uniform electric field strength profile. The proposed method does not require ionic detergent for protein separation according to their molecular weight.     

A simple and fast method for the preparation of the human cardiac myosin light chains

A simple and fast method is presented for the isolation and separation of human cardiac myosin light chains. The method requires only a crude myosin for splitting into heavy and light chains. The separation of the light chains is made by isoelectric precipitation with good yield.     

A simplified assay of enzymes catalyzing ATP-pyrophosphate exchange reactions.

The ATP-pyrophosphate exchange reaction is a widely used method for determination of the activity of enzymes forming enzyme-adenylate intermediates in the course of their catalytic action (1–4). For separation of the labeled ATP formed in the enzyme-catalyzed reaction from the labeled pyrophosphate, the adsorption of ATP on activated Norit is generally used. This method, however, is rather time consuming (considering the extensive washings required for the removal of pyrophosphate from Norit), and its reproducibility is highly dependent on pretreatment of charcoal with acid, Another method of separation applies anion-exchange paper (5). According to our experience, separation on DEAE-cellulose paper (Whatman DE 81) is not sufficient.     

Paper Chromatographic Determination of Optimum Methods for Extraction of Plant Constituents

A paper chromatographic method for the determination of suitable conditions for extraction of plant constituents is presented in this paper. The steps taken in the method are as follows: 1. Determining the optimum solvent systems from paper-chromatographic data. 2. Determination of separation method according to the separation factor β. 3. Determining the suitable volumes of solvents from the volume ratio R. 4. Calculating transfer number N for counter current distribution. It was used in determining the optimum procedure for the separation of hyoscyamine, scopolamine, esculetin, esculin and other natural compounds.     

High-performance liquid chromatography of coproporphyrin isomers.

A reversed-phase system is described for the simultaneous isocratic separation of coproporphyrin I, II, III and IV isomers. The retention behaviour of coproporphyrin I and III is studied in detail. The method is suitable for both analytical and semi-preparative separation.     

动物源活性蛋白多肽的分离纯化方法研究进展

动物类中药的有效成分以蛋白多肽为主,因此活性蛋白多肽具有重要的医疗保健价值。文章分析了沉淀法、色谱法、膜分离法以及电泳法的基本原理和主要适用范围,综述了这些方法在动物源活性蛋白多肽的分离纯化中的应用,为动物源蛋白多肽的分离纯化与进一步研究提供参考,以期开发出高效、经济和环保的蛋白多肽分离纯化新技术。     

Liposome-cell interactions. A rapid assay for cells in suspension culture

A method has been developed for the rapid separation of cells in suspension from non-cell associated lipid vesicles in various assays for vesicle-cell interaction. Separation is achieved on a discontinuous Ficoll-Paque gradient. Cells and free vesicles are totally separated, as evidenced by both radiolabelled vesicles, and vesicles containing the fluorescent dye 6-carboxyfluorescein. The main advantages of this method are the rapidity, efficacy, and gentleness of the separation. Viability of the cells remains consistently high (greater than 96%) throughout the separation. Since this method involves a one-step centrifugation, it precludes the necessity for repeated washings of cells which have been incubated with lipid vesicles.     

High-performance liquid chromatography of methylated phospholipids

A rapid high-performance liquid chromatographic method for the separation of methylated phospholipids is described. The separation is accomplished on an amine column using acetonitrile—methanol—water as the eluting solvent and UV detection at 203 nm. The choice between gradient and isocratic elution for the separation depends upon the condition of column. The method is suitable for the isolation of phosphatidylcholine, sphingomyelin, lysophosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine and lysophosphatidylethanolamine from tissues. It is applicable to the study of reaction products in phosphatide methyltransferase assay mixtures. Choline and ethanolamine plasmalogens can be determined indirectly by converting them into lysophosphatidylcholine and lysophosphatidylethanolamine with exposure to hydrochloric acid fumes.     

Separation of poly(amidoamine) (PAMAM) dendrimer generations by dynamic coating capillary electrophoresis

The separation of compounds possessing amino groups (peptides, proteins, polyamino compounds) by capillary zone electrophoresis suffers from the interaction (sticking) of these solutes with the capillary wall. This sticking can result in the absence or incomplete separation of compounds or even in their retention in the capillary. Polyamidoamine (PAMAM) dendrimers are a class of spherical polymers with primary amino groups at the surface. These compounds can be separated reasonably well at acidic pH but not at neutral pH. A new method based on the dynamic coating of the capillary was developed for the separation of these compounds at pH 7.4. The method comprises separation in a fused-silica capillary (57 cm total length, 50 cm to the detector, ID 75 microm) and a background electrolyte consisting of a Tris-phosphate buffer (50 mmol/L, pH 7.4) and 0.05% (w/v) polyethyleneimine. This system is suitable for the separation of 7 generations of dendrimers (generations 0-6). The dynamic coating agent (polyethyleneimine) also improves the separation at acid pH.     

Investigation of the parameters affecting the separation of bacterial enzymes from cell debris by tangential flow filtration

The effect of organism, enzyme, method of cell breakage and membrane characteristics on the separation of bacterial enzymes from cell debris by tangential flow filtration has been studied. The effectiveness of separation was assessed by process time, enzyme yield and specific activity, and turbidity of the filtrate. For a particular organism and enzyme, method of cell breakage and membrane characteristics significantly influenced separation performance, though results indicate that it is not yet possible to optimize all aspects of performance simultaneously.