bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isotachophoretic analysis of the end‐product and intermediates in the synthesis of the C‐terminal pentapeptide of bombinin
Authors: Friedel Klaus , Holloway Christopher J. 
Published: May 2005

AbstractCapillary isotachophoresis has been applied as an analytical monitor during the synthesis of the C‐terminal pentapeptide, Gln‐His‐Phe‐Ala‐Asn, of bombinin. The samples were separated as cations since the C‐terminal carboxyl group was modified to an uncharged amide. Potassium and beeta‐alanine were employed as leading and terminating ions and acetate was the common counter‐ion. The analyses demonstrated that the stages of synthesis up to the tripeptide, Phe‐Ala‐Asn, gave quite pure products, whereas a considerable amount of impurity was detectable after the introduction of His into the molecule. From the peptide chemist's point of view, this amino acid presents special problems. However, the impurities found in the isotachopherograms were not detectable by conventional methods such as thin‐lyer chromatography. The rapid and sensitive method of isotachophoresis should prove useful to the peptide chemist for assessment of his products, and for redesign or modification of non‐optimal synthetic strategies.
Protein concentration and recovery from gel slabs by displacement electrophoresis (isotachophoresis) and the effects of electroosmosis and counter flow
Authors: Öfverstedt Lars‐Göran , Johansson Gunnar , Froman Gunnar , Hjerten Stellan 
Published: May 2005

AbstractAlternative technical solutions of the concentration of protein samples or the recovery of proteins from gel slabs by displacement electrophoresis are demonstrated. The samples are collected at a boundary between high‐mobility leading ion and a low‐mobility terminating ion either in a small Sephadex G‐25 columns or in free solution in a rotating‐tube free electrophoresis apparatus. The boundary is kept stationary during electrophoresis by a counter flow of leading solution. Spacers and colored markers can be used to facilitate the collection of the proteins. Investigations showed that electroomosis is a very local phenomenon and that, as expected, the magnitude of the effects depends on the conductivity (field strength) of the solution. This implies that electroomosis will vary among different zones in a discontinuous system (as in displacement electrophoresis). Therefore, in most experiments om free solution it is very advantageous to arrange the system such that electrophoresis does not occur.
The use of bacteriophage T4 as a set of molecular weight and isoelectric point markers for two‐dimensional electrophoresis
Authors: Kurian Ponnamma , Gersten Douglas M. , Suhocki Paul V. , Ledley Gary 
Published: May 2005

AbstractWe have studied the use of bacteriophage T4 coat proteins as a complete set of molecular weight and isoelectric point markers for two‐dimensional electrophoresis. We present data which support the feasibility of this approach. The potential utility and advantages of this concept are discussed.
Polymerization kinetics of polyacrylamide gels II. Effect of temperature
Authors: Gelfi Cecilia , Righetti Pier Giorgio 
Published: May 2005

AbstractThe temperature at which polyacrylamide gels are polymerized strongly affects the structure and physical properties of this matrix. The suggested temperature of 0–4 °C has been found to produce highly turbid, highly porous and unelastic gels. At temperature of 25 °C of higher, the gels became progressively transparent, less porous and more elastic. This phenomenon is strongly pronounced in N,N′‐methylenebisacrylamide (Bis) gels and progressively decreases for N,N′‐(1,2‐dihydroxyethylene)bisacrylamide (DHEBA) and N,N′‐bisacrylylcystamine (BAC) gels. It has been attributed to the formation of hydrogen bonds among cross‐linker molecules, which are presumably stabilized by low temperature and progressively broken at higher temperatures. The most extensively H‐bonded compounds seem to be Bis molecules, since they can form four H‐bonds/molecule, followed by DHEBA (in which inter‐molecular H‐bonds have to compete with intra‐molecular H‐bonds) and finally by BAC, which is sparingly H‐bonded at 2 °C, and fully uncomplexed at 30°C. It is suggested that polymerization at 0–4°C should be abandoned, since it leads to unhomogeneous and unreproducible pore size matrices. Since H‐bonds in Bis molecules are fully disrupted only at 60°C (a temperature unsuitable for gel polymerization, since it produces short chains and unelastic matrices), it is also suggested that the use of Bis should be discontinued in favour of better cross‐links, such as DHEBA. In all cases, best polymerization conditions are obtained at 25–30°C. For all three cross‐linkers, homogeneous gels are obtained in presence of 8 M urea or in pure formamide as solvent, since both agents fully disrupt H‐bonds.
Incorporation of methylamine in an ultrasensitive silver stain for detecting protein in thick polyacrylamide gels
Authors: Marshall Thomas , Latner Albert L. 
Published: May 2005

AbstractAn ultrasensitive silver stain is described for the detection of proteins in 4–20 % w/v polyacrylamide gradient gels of 3mm thickness, Maximal sensitivity was achieved by substituting methylamine for ammonia in the diamine preparation and adopting a strategy of overstain followed by destain. The prediamine steps were performed at 60°C to conserve time, and the intensity of final background stain was reduced by altering the method of diamine preparation. From our experience, the technique described is more sensitive and reliable than previously published methods when applied to gels of this thickness, In any case, the sensitivity in our hands was at least equal to that of the newly described photochemical technique [7].
Two‐dimensional polyacrylamide gel electrophoresis of water‐soluble erythrocyte membrane proteins
Authors: White Mark D. , Ralston Gregory B. 
Published: May 2005

AbstractA method is reported for analyzing the oligomeric state of proteins in a mixture by multidimensional electrophoresis. Water‐soluble proteins prepared from human erythrocyte membranes were separated by means of gel filtration followed by electrophoresis in detergent‐free disc gels. The major bands in detergent‐free disc gels were identified by means of electrophoresis into a second‐dimensional slab gel containing sodium dodecyl sulphate. Detergent‐free disc gels were also subjected to two‐dimensional electrophoresis into detergent‐free slab gels consisting of a continuous gradient of polyacrylamide gel. It was shown that many of the water‐soluble proteins existed as distinct oligomers. Spectrin aggregates (tetramer and dimmer) accounted for the slowest moving bands in the detergent‐free disc gels. A water‐soluble protein of the component 3 region appeared to be present as a hexamer, while component 4.1 was present as a tetramer. Components 4.3, 4.9 and 5 appeared to be present in a large number of aggregated states. Components 7 and 8 formed a heteropolymeric protein complex.
Properdin factor B (Bf) distribution in North and Central American populations
Authors: Dykes Dale D. , Polesky Herbert F. , Crawford Michael H. 
Published: May 2005

AbstractA study of properdin factor B (Bf) in 22 North and Central American populations demonstrated gene clusters delineating Old World Caucasian, New World and Black Ancestoral groups. Result of gene frequencies were comparable to data in the literature of European Caucasian and African Blacks. New World indigeneous population were clearly separated from other racial groups with hybrid population clustering in between the major genetic contributions.
High resolution ultrathin‐layer isoelectric focusing of PGM1‐subgroups in forensic blood typing
Authors: Pflug Werner , De La Vigne Ulf , Bruder Walter 
Published: May 2005

AbstractUltrathin‐layer isoelectric focusing in 100 um polyacrylamide gels is described for the separation of the isozymes of the PGM1‐locus. The PGM1‐subgroups are best resolved in pH 5–7 gradients obtained by mixing Ampholine and Servalyt carrier ampholytes in a 2:1 ratio. By using a high field strength (180 V/cm) in the final stage of isoelectric focusing, the isozyme bands are sharper than in conventional thin‐layer gels. This facilitates identification of the subgroups. Distortions of the pH gradient are avoided if low initial field strengths (15–20 V/cm) are used. The method is highly reproducible and equally applicable for the analysis of blood samples as well as blood stains.
Agarose gel electrophoresis of bacteriophages and related particles. I. Avoidance of binding to the gel and recognizing of particles with packaged DNA
Authors: Serwer Philip , Hayes Shirley J. 
Published: May 2005

AbstractTwo potentialobstacles to using agarose gel electrophoresis for the fractionation of viruses and related particles are: (a) adherence of the sample to the gel during electrophoresis, and (b) the prolonged procedures necessary for determining whether or not particles stained with nucleic acid‐specific stains have their nucleic acid in a packaged state. It is demonstrated that adherence of positively charged tail fibers of bacteriophage T7 to agarose gels is the probable cause of a previously described (Serwer, P. and Pichler, M. E., J. Virol. 1978, 28, 917–928) sample concentration‐dependent spreading of bands formed by bacteriophage T7 during agarose gel electrophoresis (concentration effect). Procedures for screening preparations of agarose for nonadherence of particles are described and use of these procedures has resulted in the finding that the concentration effect is decreased or eliminated for T7 in preparations of agarose designed for low electro‐osmosis. In addition, it has been shown that after electrophoresis, the intensity with which bacteriophage T7 (and other DNA bacteriophages) stains with the nucleic acid‐specific stain, ethidium bromide, is increased by ejecting DNA from the interior of T7; this increase in staining intensity is used to recognized bands formed by particles with packaged DNA.
Electrophoretic cell separation using polyacrolein microspheres
Authors: Kempner David H. , Smolka Adam J. K. , Rembaum Alan 
Published: May 2005

AbstractThe electrophoretic mobility of a number of microspheres of homo‐ or copolymerized acrolein has been studied. It was found that increasing amounts of methacrylic acid increased the negative mobility of the microspheres, whereas reaction of the microspheres with 1,6‐diaminohexane decreased the negative mobility. When coated with antibody and specifically bound to cells, these microspheres were found to alter the target cells' electrophoretic mobility. This process allowed the separation of synthetic mixtures of microsphere‐labeled and unlabeled cell populations. Over 90 % of the recovered cells were found in fractions that were essentially either pure labeled or unlabeled cells.
Applicability of the log MM ‐ √D relationship to linear polyacrylamide gradient gel electrophoresis under a wide range of experimental conditions
Authors: Rothe G. M. 
Published: May 2005

AbstractRecently we reported about a linear correlation between the logarithm of the size of native proteins (log mol mass or log Stokes' radius) and the square root of their migration distance (‐ √D) in linear polyacrylamide (PAA)‐gradient gels (G. M. Rothe and H. Purkhanbaba, Electrophoresis 1982, 3, 33–42). The linearity between log MM and √D is not subject to time using homogeneous buffers in electrophoresis, no matter how the constants of the corresponding regression lines, slope and intercept change as a function of time. The realiability of this correlction has been re‐examined with 0.7 mm thin gel plates and extending the time of electrophoresis under non‐denaturating conditions from 2 to 95 h. It is demonstrated that the linear log size ‐ √D‐relationship is also applicable to sodium dodecyl sulfate (SDS) linear PAA gradient gel electrophoresis.
Rapid purification of antibodies to single band purity using recycling isoelectric focusing
Authors: Binion Steven B. , Rodkey L. Scott , Egen Ned B. , Bier Milan 
Published: May 2005

AbstractRecycling isoelectric focusing (RIEF) was used to isolate monoclonal antibodies from an electrophoretically heterogeneous rabbit antibody population. Milligram quantities of antibodies were processed to single band purity in 4 h. The ease of operation, extremely short run times, and high resolution of the RIEF apparatus give this system great flexibility. The demonstrated capacity of the RIEF system to process large quantities of protein suggests that the system is applicable to the largescale purification of antibodies.
Steady‐state rheoelectrolysis ‐ a method for isoelectric focusing without carrier ampholytes III. The influence of internal liquid flow
Authors: Rilbe Harry 
Published: May 2005

AbstractRheoelectrolysis of a salt of a weak acid with a weak base with controlled liquid exchange between anolyte and catholyte has been found to give pH courses in grave disagreement with theory. In addition, they were constantly drifting towards lower pH values. These results illustrate experimental difficulties in effectuating conditions compatible with the postulates of the theory: the drifting pH course was due to successive anodic destruction of the base, which gradually disappeared from the system, contrary to one postulate of the theory. The disagreement between the unfavourable experimental and the favourable theoretical pH course was traced to an unintentional internal liquid flow from anode to cathode, in contrast to another postulate of the theory. For that reason, the differential equation for steady‐state rheoelectrolysis with internal liquid flow is deduced and solved. The concentration courses of the ion constituents are found to be exponential instead of linear, which explains the development of an almost constant pH within a great portion of the apparatus and a steep pH change within the remaining portion. Theoretical pH courses for rheoelectrolysis with internal liquid flow are constructed and found to resemble the experimental curves very much. Quantitative information on the maximum tolerable internal flow is given.
Two‐dimensional electrophoresis of proteins in human retinal pigment epithelial cells: Identification of cytoskeletal proteins
Authors: Haley James E. , Flood Mary T. , Kjeldbye Hild M. , Maiello Eda M. , Bilek Mary K. , Gouras Peter 
Published: May 2005

AbstractTwo‐dimensional gel (2‐D) electrophoresis coupled to fluorography was used to obtain the [35S]‐methionine labeled protein profiles of cultured human retinal pigment epithelial cells. These patterns revealed about 250 polypeptides in the largely acidic isoelectric focusing 2‐D profile and approximately 200 in the mainly basic non‐equilibrium pH gradient electrophoresis 2‐D profile. The isolation of a detergent‐resistant cytoskeletal preparation revealed an enriched content of intermediate‐sized (7–10 nm) filaments as shown by electron microscopy. Two‐dimensional analysis (acidic isoelectric focusing, 2‐D) of the cytoskeletal preparation showed about 30 major proteins including non‐muscle actin, which had their counterparts in the total retinal pigment epithelium protein profile. These studies have begun to establish the subcellular local (filaments) and identity of some of the currently visualized 450 different retinal pigment epithelium proteins.
Evaluation of stained and unstained electropherograms by means of photoacoustic spectroscopy
Authors: Möller Ulrich , Köst Hans‐Peter , Schneider Siegfried , Coufal Hans 
Published: May 2005

AbstractIt is demonstrated that photoacoustic spectroscopy is a superior tool in the evaluation of electropherograms. The locla distribution of proteins in ultrathin layers of polyacrylamide gels used for isoelectric focusing is mapped with a resolution equal to or better than a laster densitomer. Even unstained samples of colored proteins can be mapped with excellent sensitivity and resolution due to the fact that the photoacoustic effect is caused only by the absorbed fraction of the incident light; scapttered light therefore doesse not cause a signal. in situ photoacosutic spectra of previously localzed zones allow the identification of the prosthetic groups of these proteins.
Two‐dimensional (crossed) immunoelectrophoresis template procedure: Use of preformed media
Authors: Saravis Calvin A. , Cook Richard B. , Sampson Christian E. , Polvino William J. 
Published: May 2005

AbstractTwo‐dimensional (crossed) immunoelectrophoresis using a two‐chamber csting cassette and a high gel strenght, low gelling temperature agarose mixture, can now be done with preformed thin antibody‐containing second dimension slab gels in a procedure that is less skill‐dependent and less injurious to heat‐labile macromolecules.
Mouse mitochondrial protein IEF 24: Identification and immunohistochemical localization of mitochondria in various tissues
Authors: Larsen Peter Mose , Fey Stephen J. , Bravo Rodrigo , Celis Julio E. 
Published: May 2005

AbstractThe abundance of mitochondrial protein IEF 24 in various Balb C mouse tissues was determined using two‐dimensional gel electrophoresis and silver staining. We found that this protein is an abundant component of all mouse tissues so far studied and these included adult brain, heart, intestine, kidney, liver, lung, muscle, skin and tongue. Comparatively little vimenting was observed in most tissues. Indirect immunofluorescent staining of methanol: acetone fixed cryostat sections from various mouse tissues using IEF 24 antibodies confirmed the mitochondrial localization of this protein but did not reveal a preferential distribution of this organelle. In contrast to these results, primary cultures of well‐spread fibroblasts from various tissues as well as of kidney epithelial cells showed in all cases the appearance of rows of well‐aligned mitochondrial fragments. These results, together with the apparently increased number of vimentin filaments observed in cultured mouse kidney fibroblasts, supported the notion that intermediate‐sized filaments of the vimentin type may serve as an anchorage site for the mitochondria in cultured cells. The lack of preferential distribution of the mitochondria observed in kidney fibrolasts in situ, which also exhibited vimentin filaments, may be due to their characteristic morphology. Cultured mouse kidney epithelial cells on the other hand showed only background fluorescence when reacted with the vimentin antibodies but showed abundant intermediate‐sized filaments of the keratin type. Based on the above results and considering the fact that many cell types in situ do not synthesize vimentin, it is proposed that both vimentin and keratin type intermediate filaments may serve as an anchorage site for the mitochondria. This proposal does does not necessarily contradict reports which indicate that mitochondria are also bound to microtubules, a possibility also suggested by our studies.
A rapid laboratory method for developing contact prints of stained polyacrylamide gels
Authors: Dunbar Bohn D. , Bundman Donnie S. , Dunbar Bonnie S. 
Published: May 2005

AbstractA rapid laboratory method for processing quality color prints of high resolution two‐dimensional polyacrylamide gels has been developed to obtain photographs for data storage or for the presentation of results in poster formats. This method involves the contact printing of a gel directly onto the film so that the final print will be an exact duplication of the size and color of the gel. A variety of papers or films can be used to produce color prints or transparencies. This method has been adapted for use with a color or with a black and white photographic enlarger.
Analysis of two‐dimensional electrophoretic protein patterns using a video camera and a computer. I. The resolution power of the video camera
Authors: Schneider Werner , Klose Joachim 
Published: May 2005

AbstractThe resolution power of a video camera (Hamamatsu) was investigated under the aspect of employing the camera for the densitometric evaluation of two‐dimensional electrophoretic patterns of proteins. The features of the camera were tested on the illuminated glass pane of a light box and on specimens such as a blank film (X‐ray film), a blank gel (polyacrylamide gel plate) and a bar raster. The digitized values were analysed by a computer. While the hardware permits a half‐tone resolution from 0 (dark) to 255 (bright) grey levels, the values obtained experimentally showed that only 90 (glass pane), 70 (gel) or 60 (film) reproducible grey levels can be resolved, depending on the features of the supporting material of the two‐dimensional electrophoresis pattern. The addressable spatial resolution of the camera comprises 1024 × 1024 pixels. Under experimental conditions, however, only 570 × 700 pixels were resolved. Further investigation in necessary to prove whether the resolution power of a video camera is sufficient for a precise analysis of two‐dimensional protein patterns.
Digital image analysis of isoelectric focusing patterns
Authors: Thomson Alan J. , Peet Frederick , Sahota Tara S. , Morrison Duncan J. , Ibaraki Anthony , White Eleanor E. 
Published: May 2005

AbstractIn a study of intersterility groups in the genus Armillaria, a scanning stage microscope photometer was used to obtain digitized images of photographs of isoelectric focusing patterns. Absorbance values were then mapped from the metric scale to the pH scale. Absorbance values in specified pH intervals were used as features in multivariate statistical procedures to characterize populations and to assign isolates to populations. Digital image analysis techniques were used to obtain an enhanced image of faint or poorly resolved bands.
Crossed immunoelectrophoretic analysis of split products of the third complement factor (C3d) following in vivo activation of the complement system
Authors: Teisner Børge , Petersen Niels E. , Folkersen Jørgen J. , Hau Jann 
Published: May 2005

AbstractSplit products of the third complement factor expressing D but not C epitopes (C3d) were analysed by crossed immunoelectrophoresis using the intermediate gel technique. Four molecular forms of C3d were identified and designated 1, 2, 3 and 4 according to their electrophoretic migration velocity. Whereas the relative concentration of molecular forms 2 and 3 were increased following acute in vivo activation and nephritic factor (NeF)‐mediated in vitro activation, the relative concentration of molecular form 1 was found to be increased in patients with chronic activation of the complement system. The results obtained by the addition of anti‐C3c antibodies to the first‐dimensional gel suggested that form 4 was a C3d‐like molecule split from the native C3 during electrophoresis. By the addition of anti‐albumin antibodies to the first‐dimensional gel it was demonstrated that molecular form 1 of C3d was a complex between C3d and albumin. The immunoprecipitation patterns of molecular forms 2 and 3 was unaffected by anti‐albumin and anti‐C3c antibodies added to the first‐dimensional gel. These data suggest that molecular forms 2 and 3 of C3d are the primary split products of C3b and these molecules are able to form a stable complex with human albumin.
Cellulose acetate electrophoresis of glycosaminoglycans in the central nervous system
Authors: Bertolotto Antonio , Magrassi Maria L. 
Published: May 2005

AbstractA new electrophoretic system, able to separate all the known standard glycosaminoglycans, was investigated as a method for the study of glycosaminoglycans extracted from tumours of the central nervous system. Densitometric analysis of standard glycosaminoglycan electrophoresis revealed high sesitivity and good repeatability. The electrophoretic system applied to biological samples based on a comigration of extracted glycosaminoglycans with standards, allowed subfractioning of chondroitinsulfates, dermatan sulfate and herapan sulfate and identifaction of heparan sulfate and heparin directly on the sheet by treatment with nitrous acid. Such characters permit the analysis of glycosaminoglycans present in small amount in biological samples.