ISSN:0173-0835    

DOI:10.1002/elps.1150040102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe moving boundary theory has been applied to the special case in which the proton and hydroxyl ion are the sole counterions. Moving boundaries between two monovalent weak acids, two biprotic acidic ampholytes, two weak bases and two biprotic basic ampholytes were considered. This application of the theory leads to constituent concentration relationships, values for pH and conductance of each phase and step pH gradients when sequential moving boundaries are considered. In addition, rigorous conditions for achieving the steady‐state in such systems are also presented. Application of the theory allows for the prediction of the formation and displacement of pH gradients. In contrast to the classical theory of pH gradients formed by ampholytes, the establishment of inverse pH gradients and the electrophoretic displacement of natural pH gradients is clearly accounted fo

ISSN:0173-0835    

DOI:10.1002/elps.1150040103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractSequential moving boundary electrophoresis with protons and hydroxyl ions as the sole counterions, consisting solely of six acids (system A) and of six bases (system B), gives rise to natural steady‐state pH gradients similar to those predicted by theory (pH 2.4–5.5 for system A, pH 10.3–12.2 for system B). Mixtures of the constituents in system A and system B gave rise to a natural pH gradient spanning the pH range between the terminal electrolytes (pH 2.4 and 12.2) predicted for systems A and B. The predicted boundary displacement is negligibly small. Experimentally the boundary displacement could not be determined in view of the difficulty of separating it from the initial transient state in which the pH gradient is formed, and a final state in which the pH gradient d

ISSN:0173-0835    

DOI:10.1002/elps.1150040104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe progressive increase in circuit resistance observed at times in polyacrylamide gel electrophoresis is attributable in part to the formation of zones of altered salt concentration at the interfaces between gel and solution. Similar changes have been reported for electrophoresis through sucrose gradients. Such zones must develop wherever migrant ions suffer a change in transport number. The paper develops a basic theory for such concentration changes. It is shown that a moving boundary will tend to arise at any interface between two media, leaving behind it a zone of altered concentration. The effect will in general be most noticeable at low ionic strengths and with electrolytes whose ions differ considerably in size, a condition applying to many common buffers. Where both ions are relatively small, diffusion is likely to obscure the boundary movement, but this will not affect the integrated change in concentration. The effect could have various deleterious consequences in gel electrophoresis, particularly in preparative apparatus. There are also implications for techniques such as isoelectric focusing and for the analysis of membrane phenomena.

ISSN:0173-0835    

DOI:10.1002/elps.1150040105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe theory developed in the previous paper is extended to cover a system containing three ions. If an “inactive” electrolyte whose ions are equally affected by a retarding medium is added to a “zone‐former” for which this is not the case, the main effect is to reduce the integrated concentration changes at the interfaces. Where a buffer contains two ions carrying charges of the same sign, the theory predicts a progressive change of pH within a zone of altered concentration. Other sources of pH change are also considered. Where a buffer includes an uncharged weak acid or base, changes in ionic concentration at an interface will lead to changes in pH. Other changes may arise from the migration of water ions, whose contributions are normally neglected. This is not justified where there are large discontinuities in conductivity. Expressions are derived for the changes in pH under different circumstances. In some cases no steady‐state is possible and there are accelerating shifts of pH at the boundaries of a zone. This could have important consequences in practical elec

ISSN:0173-0835    

DOI:10.1002/elps.1150040106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractAn assumption used in developing the basic theory, that ionic retardation factors are substantially independent of solute concentration, is tested and found valid. The results of electrophoresis through 15% polyacrylamide gels are found to be in agreement with the theory. Zones of altered concentration appear in the presence of spermine tetrahydrochloride, sodium phosphate buffer (pH 7.2) or Tris‐HCl (pH 7.0). The use of ionic retardation factors and transport numbers deduced from conductivity measurements leads to correct prediction of the sign of concentration change in each case. The direction and velocity of migration of a low‐concentration boundary can also be predicted, together with associated changes in pH. Further confirmation comes from a detailed analysis of published work on electrophoresis through sucrose gradients. The theoretical treatment is suitable for application to other systems (such as isoelectric focusing and isotachophoresis) where a gel is used as a stabilizing medium, and where effects of the kind discussed may produce unexpected distuban

ISSN:0173-0835    

DOI:10.1002/elps.1150040107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractMacromolecules isolated from human erythrocyte membranes which expressed I/i and ABH blood group activities were analyzed by quantitative immunoelectrophoretic techniques in order to determine the distribution of and the relationship between these two blood group systems. To help in these studies a rocket immunoelectrophoretic assay, with a maximum sensitivity of 10 ng, was developed which could detect and quantitate erythrocyte macromolecules which expressed I/i and A and B blood group determinants. In addition, a modification of the tandem crossed immunoelectrophoresis technique was also used to elucidate the structural relationship between determinants of these systems on one of the isolated macromolecular species. Serological and other immunological data are presented which throughly support the immunoelectrophoretic results. From these studies we have concluded that I and most likely i antigenic determinants are primarily expressed on poly(glycosyl)ceramides (i. e.macroglycolipids) and possibly to a lesser extent on Band 3. I active poly(glycosyl)ceramide could be isolated in equal quantity from any adult ABH type erythrocyte; i activity was found in similar quantity in the same fraction isolated from one i adult erythrocyte population. Besides expressing I/i activity the various poly(glycosyl)ceramide fractions also exhibited A, B or H activity as well, dependent upon the ABH cell type from which they were isolated. Unlike the equal distribution of I, however, ABH activity was type‐specific in that the poly(glycosyl)ceramide isolated from type A (either A or Ai), B or 0 cells could react only with anti‐A, anti‐B, orUlexanti‐H lectin, respectively. Using the modified tandem crossed immunoelectrophoresis (CIE) technique, it was established that the same glycolipid molecules which carry I blood group activity express the A and B determinants as well. Band 3 material isolated from 0 erythrocytes exhibited I, i and H activities. From CIE analysis the I activity of Band 3 appeared to reside in a subpopulation of this m

ISSN:0173-0835    

DOI:10.1002/elps.1150040108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractWe describe the application of a general method of comparing and sorting the patterns of protein expression obtained from two‐dimensional (2‐D) electrophoresis of a mixture of proteins. The method involved the use of two multidimensional classification programs and was applied, first, to the comparison of the protein patterns expressed at different stages during nymphal differentiation of imaginal wing discs in the insectPieris brassicae.Comparison of these stages was based on the similarity of protein expression. The technique used allowed processing of all the information visible on a gel and took into account the variations in most of the spots labeled. Two qualitatively different stages of protein expression were found during the nymphal stage, and fine variations not revealed by any other method were shown to exist in genetic programing. Next, the method was applied to sorting the different polypeptides expressed; this was also done on the basis of their similarity of expression. We were able to characterize three groups of related peptides with common regulation features and apparently common physicochemical characteristics. The complete map of the most highly correlated peptides, which may constitute subunits of the same protein, was constructed by the programs, thus permitting fast rational analysis of protein expression. The clinical applications of these classification techniques are discus

ISSN:0173-0835    

DOI:10.1002/elps.1150040109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractSearch strategies for finding spot differences among multiple two‐dimensional (2‐D) polyacrylamide electrophoresis gels are discussed in the context of the GELLAB spot data base management system. A 2‐D gel experiment should have a well‐defined biological experimental and preparation protocol reflecting the hypotheses of the problem. So too should the analysis of its corresponding 2‐D gel computer spot data base have a protocol. This protocol is heavily influenced by the nature of the biological experiment as well as 2‐D gel preparation considerations including the realities of artifactual and systematic noise. It is further influenced by constraints due to computational considerations. The search strategy is that part of the analysis protocol in which an experimenter iteratively defines tests to find significant spot differences. One goal of designing a well thought out search protocol is to reduce the number of search iterations required. Aspects of some requirements and constraints for useful search strategies ar

ISSN:0173-0835    

DOI:10.1002/elps.1150040110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractWe describe a system for accurate photometry and analysis of two‐dimensional (2‐D) gels, and its application to both high and low resolution gels. Image acquisition is video‐based and includes methods of data correction necessary for accurate photometry. The analysis is based upon a method described previously by Lutinet al.[8], which we have modified for improved stability and adapted to run on our PDP 11/60 computer. We illustrate analysis of a typical gel with a sequence of images showing the data while Gaussian components are estimated, removed, added and fitted as the iterative algorithm proceeds. We conclude by demonstrating the use of a mathematical curve‐of‐growth model for calibrating peak volumesvs.protei

ISSN:0173-0835    

DOI:10.1002/elps.1150040111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY