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1

Analysis of RNA Folding by Native Polyacrylamide Gel Electrophoresis  

Microsoft Academic Search

Polyacrylamide gel electrophoresis under native conditions (native PAGE) is a well-established and versatile method for probing nucleic acid conformation and nucleic acid–protein interactions. Native PAGE has been used to measure RNA folding equilibria and kinetics under a wide variety of conditions. Advantages of this method are its adaptability, absolute determination of reaction endpoints, and direct analysis of conformational hetereogeneity within

Sarah A. Woodson; Eda Koculi

2009-01-01

2

Complex III staining in blue native polyacrylamide gels  

Microsoft Academic Search

For more than a decade now blue native polyacrylamide gel electrophoresis (BN-PAGE) has been used for the study of the oxidative\\u000a phosphorylation (OXPHOS) complexes. Catalytic activities of complexes I, II, IV and V can be assessed, after separation by\\u000a gel electroforesis, by incubation of the BN-PAGE gel in specific staining solutions. However, until now, a reliable staining\\u000a method for testing

Joél Smet; Boel De Paepe; Sara Seneca; Willy Lissens; Heike Kotarsky; Linda De Meirleir; Vineta Fellman; Rudy Van Coster

2011-01-01

3

Blue Native Polyacrylamide Gel Electrophoresis (BN-PAGE) for Analysis of Multiprotein Complexes from Cellular Lysates  

PubMed Central

Multiprotein complexes (MPCs) play a crucial role in cell signalling, since most proteins can be found in functional or regulatory complexes with other proteins (Sali, Glaeser et al. 2003). Thus, the study of protein-protein interaction networks requires the detailed characterization of MPCs to gain an integrative understanding of protein function and regulation. For identification and analysis, MPCs must be separated under native conditions. In this video, we describe the analysis of MPCs by blue native polyacrylamide gel electrophoresis (BN-PAGE). BN-PAGE is a technique that allows separation of MPCs in a native conformation with a higher resolution than offered by gel filtration or sucrose density ultracentrifugation, and is therefore useful to determine MPC size, composition, and relative abundance (Schägger and von Jagow 1991); (Schägger, Cramer et al. 1994). By this method, proteins are separated according to their hydrodynamic size and shape in a polyacrylamide matrix. Here, we demonstrate the analysis of MPCs of total cellular lysates, pointing out that lysate dialysis is the crucial step to make BN-PAGE applicable to these biological samples. Using a combination of first dimension BN- and second dimension SDS-PAGE, we show that MPCs separated by BN-PAGE can be further subdivided into their individual constituents by SDS-PAGE. Visualization of the MPC components upon gel separation is performed by standard immunoblotting. As an example for MPC analysis by BN-PAGE, we chose the well-characterized eukaryotic 19S, 20S, and 26S proteasomes.

Fiala, Gina J.

2011-01-01

4

Analysis of the phospholipase C-?1 pleckstrin homology domain using native polyacrylamide gel electrophoresis.  

PubMed

The phospholipase C (PLC)-?1 pleckstrin homology (PH) domain has a characteristic short ?-helix (?2) from residues 82 to 87. The contributions of the ?2-helix toward the inositol 1,4,5-trisphosphate (IP(3)) binding activity and thermal stability of the PLC-?1 PH domain were investigated using native polyacrylamide gel electrophoresis (PAGE). Native PAGE analyses of gel migration shift induced by IP(3) binding and of protein aggregation induced by heating indicated that disruption of the ?-helical conformation by replacement of Lys86 with proline resulted in reduced affinity for IP(3) and in thermal destabilization of the IP(3)-binding state. Although the mutant protein with replacement of Lys86 with alanine showed a slight reduction in thermal stability, the IP(3)-binding affinity was similar to that of the wild-type protein. Replacement of Phe87 with alanine, but not with tyrosine, also resulted in reduced affinity for IP(3) and in thermal instability. These results indicated that the helical conformation of the ?2-helix and the phenyl ring of Phe87 play important roles in the IP(3)-binding activity and thermal stability of the PLC-?1 PH domain. Based on these results, the biological role of the ?2-helix of the PLC-?1 PH domain is discussed in terms of membrane binding. PMID:22995066

Tanio, Michikazu; Nishimura, Katsuyuki

2012-09-18

5

Functional Characterization of Reductive Dehalogenases by Using Blue Native Polyacrylamide Gel Electrophoresis  

PubMed Central

Dehalococcoides mccartyi strains are obligate organohalide-respiring bacteria harboring multiple distinct reductive dehalogenase (RDase) genes within their genomes. A major challenge is to identify substrates for the enzymes encoded by these RDase genes. We demonstrate an approach that involves blue native polyacrylamide gel electrophoresis (BN-PAGE) followed by enzyme activity assays with gel slices and subsequent identification of proteins in gel slices using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RDase expression was investigated in cultures of Dehalococcoides mccartyi strain BAV1 and in the KB-1 consortium growing on chlorinated ethenes and 1,2-dichloroethane. In cultures of strain BAV1, BvcA was the only RDase detected, revealing that this enzyme catalyzes the dechlorination not only of vinyl chloride, but also of all dichloroethene isomers and 1,2-dichloroethane. In cultures of consortium KB-1, five distinct Dehalococcoides RDases and one Geobacter RDase were expressed under the conditions tested. Three of the five RDases included orthologs to the previously identified chlorinated ethene-dechlorinating enzymes VcrA, BvcA, and TceA. This study revealed substrate promiscuity for these three enzymes and provides a path forward to further explore the largely unknown RDase protein family.

Tang, Shuiquan; Chan, Winnie W. M.; Fletcher, Kelly E.; Seifert, Jana; Liang, Xiaoming; Loffler, Frank E.; Adrian, Lorenz

2013-01-01

6

Functional characterization of reductive dehalogenases by using blue native polyacrylamide gel electrophoresis.  

PubMed

Dehalococcoides mccartyi strains are obligate organohalide-respiring bacteria harboring multiple distinct reductive dehalogenase (RDase) genes within their genomes. A major challenge is to identify substrates for the enzymes encoded by these RDase genes. We demonstrate an approach that involves blue native polyacrylamide gel electrophoresis (BN-PAGE) followed by enzyme activity assays with gel slices and subsequent identification of proteins in gel slices using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RDase expression was investigated in cultures of Dehalococcoides mccartyi strain BAV1 and in the KB-1 consortium growing on chlorinated ethenes and 1,2-dichloroethane. In cultures of strain BAV1, BvcA was the only RDase detected, revealing that this enzyme catalyzes the dechlorination not only of vinyl chloride, but also of all dichloroethene isomers and 1,2-dichloroethane. In cultures of consortium KB-1, five distinct Dehalococcoides RDases and one Geobacter RDase were expressed under the conditions tested. Three of the five RDases included orthologs to the previously identified chlorinated ethene-dechlorinating enzymes VcrA, BvcA, and TceA. This study revealed substrate promiscuity for these three enzymes and provides a path forward to further explore the largely unknown RDase protein family. PMID:23204411

Tang, Shuiquan; Chan, Winnie W M; Fletcher, Kelly E; Seifert, Jana; Liang, Xiaoming; Löffler, Frank E; Edwards, Elizabeth A; Adrian, Lorenz

2012-11-30

7

In-gel staining of proteins in native polyacrylamide gel electrophoresis using meso-tetrakis(4-sulfonatophenyl) porphyrin.  

PubMed

Protein identification in polyacrylamide gel electrophoresis (PAGE) requires post-electrophoretic steps like fixing, staining, and destaining of the gel, which are time-consuming and cumbersome. A new method for direct visualization of protein bands in PAGE has been developed using meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) as a dye without the need for any post-electrophoretic steps; thus, separation and recovery of enzymes become much easier for further analysis. Activity staining was carried out to show that the biochemical activity of the enzymes was preserved after electrophoresis. PMID:22585523

Divakar, K; Devi, G Nandhini; Gautam, Pennathur

2012-01-01

8

Measuring the Quantity and Activity of Mitochondrial Electron Transport Chain Complexes in Tissues of Central Nervous System Using Blue Native Polyacrylamide Gel Electrophoresis  

Microsoft Academic Search

Mitochondrial dysfunction and degeneration are associated with many neurodegenerative disorders. A dysfunctional mitochondrial electron transport chain (ETC) impairs ATP production and accelerates the generation of free radicals. To evaluate mitochondrial function, reliable methods are needed. Conventional spectrophotometric assays may not eliminate interference from nonspecific enzyme activities and do not measure quantities of specific ETC complexes. Blue native polyacrylamide gel electrophoresis

Cheolwha Jung; Cynthia M. J. Higgins; Zuoshang Xu

2000-01-01

9

A Modified Polyacrylamide Gel Slicer.  

National Technical Information Service (NTIS)

The polyacrylamide gel slicer described by Goldberger in 1968 contained two critical parts which are no longer commercially available. Design changes are presented which allow for construction of this device at reduced cost, using readily available parts....

G. L. Moore C. D. Purpura

1970-01-01

10

Localization of discontinuous epitopes of herpes simplex virus glycoprotein D: use of a nondenaturing ("native" gel) system of polyacrylamide gel electrophoresis coupled with Western blotting.  

PubMed Central

Previously, a panel of monoclonal antibodies (MCAb) was used to define specific epitopes of herpes simplex virus glycoprotein D (gD) (R. J. Eisenberg et al., J. Virol. 53:634-644, 1985). Three groups of antibodies recognized continuous epitopes; group VII reacted with residues 11 to 19 of the mature protein (residues 36 to 44 of the predicted sequence), group II reacted with residues 272 to 279, and group V reacted with residues 340 to 356. Four additional antibody groups recognized discontinuous epitopes of gD, since their reactivity was lost when the glycoprotein was denatured by reduction and alkylation. Our goal in this study was to localize more precisely the discontinuous epitopes of gD. Using a nondenaturing system of polyacrylamide gel electrophoresis ("native" gel electrophoresis) coupled to Western blotting, we analyzed the antigenic activity of truncated forms of gD. These fragments were generated either by recombinant DNA methods or by cleavage of purified native gD-1 (gD obtained from herpes simplex virus type 1) and gD-2 (gD obtained from herpes simplex virus type 2) with Staphylococcus aureus protease V8. Antibodies in groups III, IV, and VI recognized three truncated forms of gD-1 produced by recombinant DNA methods, residues 1 to 287, 1 to 275, and 1 to 233. Antibodies in group I recognized the two larger forms but did not react with the gD-1 fragment of residues 1 to 233. On the basis of these and previous results, we concluded that a protion of epitope I was located within residues 233 to 259 and that epitopes III, IV, and VI were upstream of residue 233. Antibodies to continuous epitopes identified protease V8 fragments of gD-1 and gD-2 that contained portions of either the amino or carboxy regions of the proteins. None of the V8 fragments, including a 34K polypeptide containing residues 227 to 369, reacted with group I antibodies. This result indicated that a second portion of epitope I was located upstream of residue 227. Two amino-terminal fragments of gD-1, 33K and 30K, reacted with group III, IV, and VI antibodies. A 33K fragment of gD-2 reacted with group III antibodies. Based on their size and reactivity with endo-beta-N-acetylglycosaminidase F, we hypothesized that the 33K and 30K molecules represented residues 1 to 226 and 1 to 182 of gD-1, respectively. These results suggest that epitopes III, IV, and VI are located within the first 182 residues of gD.(ABSTRACT TRUNCATED AT 400 WORDS) Images

Cohen, G H; Isola, V J; Kuhns, J; Berman, P W; Eisenberg, R J

1986-01-01

11

Oil recovery process using a polyacrylamide gel  

SciTech Connect

A polymer gel is formulated by adding a cross-linking agent containing a polyvalent metal cation to an aqueous solution of undried partially hydrolyzed polyacrylamide. The resulting gel is dissolved or suspended in an aqueous medium and injected via a well into a subterranean hydrocarbon-bearing formation to improve oil recovery from the formation.

Norton, C. J.; Falk, D. O.; Hill, A. D.

1985-12-31

12

Polyacrylamide/graphite and polyacrylamide/titanium dioxide gel electrodes  

SciTech Connect

Polyacrylamide (pacr) gels have attractive properties that are the basis for several important applications in bioanalytical chemistry. For example, they provide a hydrophilic environment with a controllable pore size that allows for the entrapment and immobilization of biopolymers in their active forms. Pacr gels have long been used as matrices for gel electrophoresis and gel permeation chromatography. Recently, they described the construction of an enzyme electrode, based on the ideas of Hill and co-workers, that consisted of an enzyme/mediator system entrapped in a pacr interface between a carbon support bed and the solution. These pacr-modified electrodes mediated the direct and specific amperometric oxidation of glucose. Others have studied pacr-modified electrodes, and a variety of applications based on the electrochemically driven swelling of polyelectrolyte gels can be envisioned. Thus these electrodes show promise as permeable, multicomponent interfaces between an electrode substrate and solution. The purpose of the work described here was 3-fold: first, to study charge transport through the ferrocene/graphite/pacr gel composite; second, to document preliminary investigations of the photoactivation process occurring in the ferrocene/TiO/sub 2//pacr gel; and third, to examine the analytical utility of the pacr electrode.

Lange, M.A.; Chambers, J.Q.

1986-11-01

13

Silver staining of proteins in polyacrylamide gels  

PubMed Central

Silver staining is used to detect proteins after electrophoretic separation on polyacrylamide gels. It combines excellent sensitivity (in the low nanogram range) whilst using very simple and cheap equipment and chemicals. It is compatible with downstream processing such as mass spectrometry analysis after protein digestion. The sequential phases of silver staining are protein fixation, then sensitization, then silver impregnation and finally image development. Several variants of silver staining are described here, which can be completed in a time range from 2 hours to one day after the end of the electrophoretic separation. Once completed, the stain is stable for several weeks

Chevallet, Mireille; Luche, Sylvie; Rabilloud, Thierry

2006-01-01

14

Investigations in x-ray computed tomography polyacrylamide gel dosimetry  

Microsoft Academic Search

Polyacrylamide gels (PAGs) are radiosensitive materials currently under development for use as three dimensional (3D) dosimeters in radiation therapy. Dose information is recorded in the gels and extracted through imaging. X-ray computed tomography (CT) has emerged as a promising gel imaging method due to a change in gel density that occurs upon irradiation. The accessibility of CT technology to cancer

Michelle Louise Hilts

2005-01-01

15

A polyacrylamide gel phantom for radiofrequency ablation.  

PubMed

A polyacrylamide gel (PAG) containing bovine serum albumin (BSA) is introduced as a new tissue-mimicking phantom for the purpose of visualizing three-dimensional coagulation temperature distribution during radiofrequency ablation (RFA). The coagulation temperature of the phantom can be changed at the same range of biological tissue (50-60 degrees C) by adjusting the pH from 4.3 to 4.7. The phantom is transparent except in thermal coagulation regions which are ivory white. The physical properties of the phantom, such as density, electrical conductivity and specific heat capacity, are very favorable, similar to those of soft tissues. We illustrate the usefulness of the phantom in visualizing RFA lesions. This phantom has magnetic resonance properties which change drastically upon thermal coagulation, enabling its use for the characterization of RFA device, quality assurance, treatment planning and treatment verification. The PAG containing BSA, whose pH was adjusted from 4.3 to 4.7, is an attractive tissue-mimicking phantom suitable for RFA investigations. PMID:18608575

Bu-Lin, Zhang; Bing, Hu; Sheng-Li, Kuang; Huang, Ying; Rong, Wu; Jia, Li

2008-11-01

16

Detection of polyhydroxyalkanoate synthase activity on a polyacrylamide gel  

Microsoft Academic Search

This study presents a method to detect active polyhydroxyalkanoate (PHA) synthase on a polyacrylamide gel that combines the polyhydroxybutyrate (PHB) polymerization reaction with Sudan Black B staining. After separation of the protein samples on a modified sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), the slab gel was submerged in a buffer containing ?-hydroxybutyryl–coenzyme A (3-HBCoA) as substrate and incubated at room

Der-Shyan Sheu; Yung-Wei Lai; Rey-Chang Chang; Wen-Ming Chen

2009-01-01

17

Polyacrylamide gels synthesized in the presence of surfactants  

Microsoft Academic Search

The polymerization of acrylamide monomers in the presence of surfactant self-assemblies produces gels with variable pore architecture. Polyacrylamide gels were formed by polymerizing acrylamide plus a cross-linker in the presence of surfactants, which were then removed by soaking in distilled water. Gels formed in the presence of over 28% surfactant (by weight) formed clear, but became opaque upon removal of

Mukundan Chakrapani

2002-01-01

18

Complications of Breast Augmentation with Injected Hydrophilic Polyacrylamide Gel  

Microsoft Academic Search

  Since 1997, the hydrophilic polyacrylamide gel (PAAG), an injectable alloplastic biomaterial, imported from the Ukraine has\\u000a been used for augmentation mammaplasty in China. There were twelve patients with various complications visiting our hospitals\\u000a after breast augmentation with injected hydrophilic polyacrylamide gel by other clinics, even though such procedures are not\\u000a performed in our clinical practices. The complications included four cases

Ning-xin Cheng; Yuan-lu Wang; Jin-huang Wang; Xiao-man Zhang; Hong Zhong

2002-01-01

19

Electrophoretic transfer as a technique for the detection and identification of plant amylolytic enzymes in polyacrylamide gels.  

PubMed

An electrophoretic transfer technique was developed for the specific identification of isozymes of starch debranching enzyme, alpha-amylase, and beta-amylase. Amylolytic enzymes are separated by native polyacrylamide slab gel electrophoresis and proteins in gels are electrophoretically transferred through starch-containing polyacrylamide gels. Each amylolytic enzyme degrades starch in the transfer gel to its characteristic limit dextrin as it moves through the gel. Various limit dextrins in the starch gel are identified by their characteristic color development in KI/I solution. Isozymes of starch debranching enzyme, alpha-amylase, and beta-amylase can be easily identified in the same gel. PMID:16663595

Kakefuda, G; Duke, S H

1984-05-01

20

Combining blue native polyacrylamide gel electrophoresis with liquid chromatography tandem mass spectrometry as an effective strategy for analyzing potential membrane protein complexes of Mycobacterium bovis bacillus Calmette-Gu?rin  

PubMed Central

Background Tuberculosis is an infectious bacterial disease in humans caused primarily by Mycobacterium tuberculosis, and infects one-third of the world's total population. Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine has been widely used to prevent tuberculosis worldwide since 1921. Membrane proteins play important roles in various cellular processes, and the protein-protein interactions involved in these processes may provide further information about molecular organization and cellular pathways. However, membrane proteins are notoriously under-represented by traditional two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and little is known about mycobacterial membrane and membrane-associated protein complexes. Here we investigated M. bovis BCG by an alternative proteomic strategy coupling blue native PAGE to liquid chromatography tandem mass spectrometry (LC-MS/MS) to characterize potential protein-protein interactions in membrane fractions. Results Using this approach, we analyzed native molecular composition of protein complexes in BCG membrane fractions. As a result, 40 proteins (including 12 integral membrane proteins), which were organized in 9 different gel bands, were unambiguous identified. The proteins identified have been experimentally confirmed using 2-D SDS PAGE. We identified MmpL8 and four neighboring proteins that were involved in lipid transport complexes, and all subunits of ATP synthase complex in their monomeric states. Two phenolpthiocerol synthases and three arabinosyltransferases belonging to individual operons were obtained in different gel bands. Furthermore, two giant multifunctional enzymes, Pks7 and Pks8, and four mycobacterial Hsp family members were determined. Additionally, seven ribosomal proteins involved in polyribosome complex and two subunits of the succinate dehydrogenase complex were also found. Notablely, some proteins with high hydrophobicity or multiple transmembrane helixes were identified well in our work. Conclusions In this study, we utilized LC-MS/MS in combination with blue native PAGE to characterize modular components of multiprotein complexes in BCG membrane fractions. The results demonstrated that the proteomic strategy was a reliable and reproducible tool for analysis of BCG multiprotein complexes. The identification in our study may provide some evidence for further study of BCG protein interaction.

2011-01-01

21

Nondenaturing electrophoresis of lipoproteins in agarose and polyacrylamide gradient gels  

Microsoft Academic Search

The plasma lipoproteins frequently are classified according to density and\\/or electrophoretic mobility. The lipoprotein classes differ characteristically also in particle size and apolipoprotein composition. Each class is heterogeneous in size and composition as well. Nondenaturing electrophoresis in agarose gels and polyacrylamide gradient gels are complementary analytical methods for classification of lipoproteins and determining distribution profiles of the major classes. In

1989-01-01

22

Purification of DNA Oligos by Denaturing Polyacrylamide Gel Electrophoresis (PAGE).  

PubMed

After chemical synthesis, the oligonucleotide preparation contains the desired full-length oligonucleotide but also all of the DNA molecules that were aborted during each cycle in the synthesis, and the by-products generated during the chemical reactions. The purification of oligonucleotides is a critical step for demanding applications where the exact length or sequence of the oligonucleotide is important, or for oligonucleotides longer than 50 bases. There are several methods of increasing oligonucleotide purity, the choice of which will depend on modifications of the oligonucleotides and their intended use. Polyacrylamide gel purification (PAGE purification) is the method of choice when the highest percentage of full-length oligonucleotide is desired. This chapter describes a protocol for oligonucleotide purification using denaturing polyacrylamide gel electrophoresis, and includes oligonucleotide preparation, polyacrylamide gel electrophoresis, and purification from the gel slice by two different methods: by diffusion or by electroelution. This chapter also includes recommendations as well as protocol advice. PMID:24011037

Lopez-Gomollon, Sara; Nicolas, Francisco Esteban

2013-01-01

23

Nondenaturing electrophoresis of lipoproteins in agarose and polyacrylamide gradient gels  

SciTech Connect

The plasma lipoproteins frequently are classified according to density and/or electrophoretic mobility. The lipoprotein classes differ characteristically also in particle size and apolipoprotein composition. Each class is heterogeneous in size and composition as well. Nondenaturing electrophoresis in agarose gels and polyacrylamide gradient gels are complementary analytical methods for classification of lipoproteins and determining distribution profiles of the major classes. In addition, gradient gel electrophoresis (GGE) has a high resolving capability for subfractionating each class according to particle size. Combination of gel electrophoresis with immunoblotting yields information on heterogeneity in apolipoprotein distribution. 14 refs., 6 figs., 3 tabs.

Shore, V.G.

1989-12-19

24

Activity staining of endoglucanases in polyacrylamide gels.  

PubMed

The endoglucanases of Penicillium funiculosum were analyzed for the presence of multiple forms using a modified version of the Congo red method. Postelectrophoretic slab gels were directly incubated in a solution of carboxymethylcellulose for a period as short as 15 min and then the activities were visualized by staining with Congo red. Ten distinct bands of clearances were obtained indicating the presence of at least as many multiple forms. PMID:1280921

Mathew, R; Rao, K K

1992-10-01

25

Renaturation of enzymes after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate  

SciTech Connect

A number of enzymes, including amylases, dehydrogenases, and proteases, were shown to be renaturable after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Enzyme activity was detected in situ by action on substrates introduced into the gel and subsequent staining of either the product or unreacted substrate. Enzymes appeared to recover activity as soon as the detergent diffused out of the gel. Renatured enzymes were retained in gels after electrophoresis longer than native enzymes which had been subjected to electrophoresis in the absence of detergent. Re-electrophoresis of the renatured enzymes showed that part of the retained activity was physically anchored to the gel, possibly by the folding of polypeptides around the gel matrix as the enzymes were renatured.

Lacks, S.A.; Springhorn, S.S.

1980-08-10

26

Polyphenol oxidase activity staining in polyacrylamide electrophoresis gels.  

PubMed

An analytical method allowing the detection of polyphenol oxidase activity on polyacrylamide gel electrophoresis (PAGE) is described. The method is rapid, sensitive and specific and is based on a coupling reaction between 4-tert-butyl-o-benzoquinone and the aromatic amine, 4-amino-N,N-diethylaniline sulphate. Catecholase activity of polyphenol oxidase appears as blue stained bands on a colourless background. PMID:9178091

Rescigno, A; Sollai, F; Rinaldi, A C; Soddu, G; Sanjust, E

1997-03-27

27

Visible fluorescent detection of proteins in polyacrylamide gels without staining  

Microsoft Academic Search

2,2,2-Trichloroethanol (TCE) incorporated into polyacrylamide gels before polymerization provides fluorescent visible detection of proteins in less than 5min of total processing time. The tryptophans in proteins undergo an ultraviolet light-induced reaction with trihalocompounds to produce fluorescence in the visible range so that the protein bands can be visualized on a 300-nm transilluminator. In a previous study trichloroacetic acid or chloroform

Carol L Ladner; Jing Yang; Raymond J Turner; Robert A Edwards

2004-01-01

28

Structural Transition of Non-ionic Poly(acrylamide) Gel  

NASA Astrophysics Data System (ADS)

We discuss the structure of the opaque poly(acrylamide) gel that is synthesized at higher mole fractions of the cross-linking agent above 0.2. The structure of the opaque gel is analyzed by the small angle neutron scattering technique. The fractal analysis of the scattering function yields that the polymer network of the opaque poly(acrylamide) gel can be seen as a mass fractal of the fractal dimension of about DM ˜ 2.7 when the mole fraction of the cross-linker is higher than 0.3. On the other hand, much larger exponents are obtained in the lower concentration region of the cross-linker less than 0.3. It suggests that the polymer network of the gel behaves as a surface fractal of the fractal dimension of DS ˜ 2.5. The structure of the polymer network changes from the surface fractal to the mass fractal at the mole fraction of the cross-linker is 0.3 when the mole fraction of the cross-linker is increased from 0.2 to 0.5. The structure of the gel is also observed by using the confocal laser scanning microscope. The fractal analysis of the confocal images indicate that the fractal dimension of the two dimensional distribution of the colloidal particles in the cross section of the colloidal aggregate is found to be about 1.7.

Mukai, Sada-Atsu; Miki, Hirohisa; Garamus, Vasyl; Willmeit, Regine; Tokita, Masayuki

29

Characterization of DNA metabolizing enzymes in situ following polyacrylamide gel electrophoresis  

SciTech Connect

The authors have detected the in situ activities of DNA glycosylase, endonuclease, exonuclease, DNA polymerase, and DNA ligase using a novel polyacrylamide activity gel electrophoresis procedure. DNA metabolizing enzymes were resolved through either native or SDS-polyacrylamide gels containing defined {sup 32}P-labeled oligonucleotides annealed to M13 DNA. After electrophoresis, these enzymes catalyzed in situ reactions and their ({sup 32}P)DNA products were resolved from the gel by a second dimension of electrophoresis through a denaturing DNA sequencing gel. Detection of modified (degraded or elongated) oligonucleotide chains was used to locate various enzyme activities. The catalytic and physical properties of Novikoff hepatoma DNA polymerase {beta} were found to be similar under both in vitro and in situ conditions. With 3{prime}-terminally matched and mismatched ({sup 32}P)DNA substrates in the same activity gel, DNA polymerase and/or 3{prime} to 5{prime} exonuclease activities of Escherichia coli DNA polymerase I (large fragment), DNA polymerase III (holoenzyme), and exonuclease III were detected and characterized. Several restriction endonucleases and the tripeptide (Lys-Try-Lys), which acts as an apurinic/apyrimidinic endonuclease, were able to diffuse into gels and modify DNA. This ability to create intermediate substrates within activity gels could prove extremely useful in delineating the steps of DNA replication and repair pathways.

Longley, M.J.; Mosbaugh, D.W. (Oregon State Univ., Corvallis (United States))

1991-03-12

30

Aggregative properties of Rhodamine dyes in polyacrylamide hydrophilic gel media  

NASA Astrophysics Data System (ADS)

The visible absorption spectra of two Rhodamine dyes (R6G and RB) in aqueous solutions, and in the polyacrylamide hydrogel matrix with different composition were studied at room temperature. The spectral properties of the dye-loaded hydrogel were also investigated. The transport and the solute-solute interactions of the ionic dyes in aqueous solutions across the hydrophilic gels were calculated. The monomer-dimer equilibrium of these ionic dyes in water and in different composition of hydrogel environment with different soaking time has been investigated by means of UV-Vis spectroscopy. The natures of the interacting pairs in these dyes were discussed using the Kasha exciton theory.

Zakerhamidi, M. S.; Moghadam, M.; Karimi, A.

2013-02-01

31

Crosslinked, Flexible, Low-Molecular-Weight Polyacrylamide Gels for Mobility Control: Topical Report.  

National Technical Information Service (NTIS)

This project is a continuation of a research program initiated in FY88 to develop shear-resistant flexible gels based on crosslinking a low-molecular-weight polyacrylamide for mobility control. Polyacrylamide was crosslinked with aluminum citrate and chro...

H. W. Gao

1989-01-01

32

Investigations in x-ray computed tomography polyacrylamide gel dosimetry  

SciTech Connect

Polyacrylamide gels (PAGs) are radiosensitive materials currently under development for use as three-dimensional (3D) dosimeters in radiation therapy. Dose information is recorded in the gels and extracted through imaging. X-ray computed tomography (CT) has emerged as a promising gel imaging method due to a change in gel density that occurs upon irradiation. The accessibility of CT technology to cancer hospitals makes CT read out clinically attractive; however, the technique remains of limited clinical use due in part to poor dose resolution. This thesis investigates the use of CT for extracting dose information from PAGs with an overall goal of improving achievable dose resolution. Thesis results are divided into three studies: a gel-compositional study, a study of noise and dose resolution, and a digital filtering study. The first study investigates the effects of gel composition on PAG CT dose response and the underlying density change. Results indicate dramatic variation in CT dose response sensitivity and range with gel composition. A model is developed to describe gel density change with dose, revealing two fundamental properties of the density to dose response: the density change per unit polymer yield is highest for gels with low and high concentrations of crosslinking molecules, and dose response sensitivity is linearly dependent on the total concentration of monomers in the gel. The second study investigates strategies for minimizing noise in CT polymer gel dosimetry and assesses system performance. Specifically, the effects of phantom design, scanning technique, and voxel size on image noise are investigated and the effect of scanning protocol on imaging time is established. The dose resolution achievable with an optimized system is then calculated, given voxel size and imaging time constraints, and compared with published values for magnetic resonance imaging (MRI) and optical CT gel dosimetry. The third study investigates the potential of image filtering for improved dose resolution in CT gel dosimetry. CT image noise is characterized and appropriate filters are tested on a CT image of a PAG irradiated with a clinically relevant dose distribution. Filter performance is found to vary dramatically, with the best filters more than halving the dose resolution without significantly distorting the spatial distribution of dose. In summary, this thesis provides insight into the fundamental nature of PAG density to dose response, develops strategies for minimizing image noise, quantifies system performance, and demonstrates that digital image filtering is an effective tool to provide additional improvements to dose resolution.

Hilts, Michelle [Physics and Astronomy, University of British Columbia, British Columbia, Canada and Medical Physics, BC Cancer Agency, Vancouver Centre, British Columbia (Canada)]. E-mail: mhilts@bccancer.bc.ca

2005-09-15

33

Glutamine Synthetase Regulation, Adenylylation State, and Strain Specificity Analyzed by Polyacrylamide Gel Electrophoresis  

PubMed Central

We used polyacrylamide gel electrophoresis to examine the regulation and adenylylation states of glutamine synthetases (GSs) from Escherichia coli (GSE) and Klebsiella aerogenes (GSK). In gels containing sodium dodecyl sulfate (SDS), we found that GSK had a mobility which differed significantly from that of GSE. In addition, for both GSK and GSE, adenylylated subunits (GSK-adenosine 5?-monophosphate [AMP] and GSE-AMP) had lesser mobilities in SDS gels than did the corresponding non-adenylylated subunits. The order of mobilities was GSK-AMP < GSK < GSE-AMP < GSE. We were able to detect these mobility differences with purified and partially purified preparations of GS, crude cell extracts, and whole cell lysates. SDS gel electrophoresis thus provided a means of estimating the adenylylation state and the quantity of GS present independent of enzymatic activity measurements and of determining the strain origin. Using SDS gels, we showed that: (i) the constitutively produced GS in strains carrying the glnA4 allele was mostly adenylylated, (ii) the GS-like polypeptide produced by strains carrying the glnA51 allele was indistinguishable from wild-type GSK, and (iii) strains carrying the glnA10 allele contained no polypeptide having the mobility of GSK or GSK-AMP. Using native polyacrylamide gels, we detected the increased amount of dodecameric GS present in cells grown under nitrogen limitation compared with cells grown under conditions of nitrogen excess. In native gels there was neither a significant difference in the mobilities of adenylylated and non-adenylylated GSs nor a GS-like protein in cells carrying the glnA10 allele. Images

Bender, Robert A.; Streicher, Stanley L.

1979-01-01

34

Improved recovery of DNA from polyacrylamide gels after in situ DNA footprinting.  

PubMed

Methods used to date for the isolation of DNA from polyacrylamide gels are elution based, time-consuming and with low yield in DNA. This paper describes an improved system employing polyacrylamide gels made of a meltable matrix. The new system was successfully applied to in situ DNA footprinting following gel retardation assays. PMID:12782386

van Keulen, Geertje; Meijer, Wim G

2003-08-01

35

Investigations in x-ray computed tomography polyacrylamide gel dosimetry  

NASA Astrophysics Data System (ADS)

Polyacrylamide gels (PAGs) are radiosensitive materials currently under development for use as three dimensional (3D) dosimeters in radiation therapy. Dose information is recorded in the gels and extracted through imaging. X-ray computed tomography (CT) has emerged as a promising gel imaging method due to a change in gel density that occurs upon irradiation. The accessibility of CT technology to cancer hospitals makes CT read-out clinically attractive, however the technique remains of limited clinical use due in part to poor dose resolution. This thesis investigates the use of CT for extracting dose information from PAG with an overall goal to improve achievable dose resolution. Thesis results are divided into three studies: a gel compositional study, a study of noise and dose resolution and a digital filtering study. The first study investigates the effects of gel composition on PAG CT dose response and the underlying density change. Systems for irradiating and imaging gels are designed and tested and dose response reproducibility is established. Results indicate dramatic variation in CT dose response sensitivity and range with gel composition. A model is developed to describe gel density change with dose, revealing two fundamental properties of the density to dose response: the density change that occurs per unit polymer yield is highest for gels with low and high concentrations of crosslinking molecule (%C) and the dose response sensitivity is linearly dependent on the total concentration of monomer in the gel. The second study investigates strategies for minimizing noise in x-ray CT polymer gel dosimetry and assesses system performance. Specifically, the effects of phantom design, scanning technique and image voxel size on image noise are investigated. This work leads to the establishment of a method of predicting image noise for any given CT imaging protocol. Image uniformity is also assessed, in the context of noise levels in gel dosimetry. The effect of scanning protocol on imaging time is established and the dose resolution achievable with an optimized system is calculated given voxel size and imaging time constraints. These results, when compared with published values for MRI and optical CT gel dosimetry indicate that CT dose resolution (e.g. 5%, 1 x 1 x 3 mm3 voxels), is still not at the level of the best MRI or optical CT techniques, however fast imaging times makes the rapid acquisition of volumetric data most feasible with x-ray CT. The third study investigates the potential of image filtering for improved dose resolution in CT gel dosimetry. CT image noise is characterized as Gaussian distributed and independent of signal strength and filters for reducing spatially invariant noise are investigated: mean, median, midpoint, adaptive mean, alpha-trimmed mean, sigma mean and a relatively new filter called SUSAN. The filters are tested on a CT image of a PAG irradiated with a clinically relevant dose distribution. Filter performance varies greatly in both achieved dose resolution and affects on the spatial distribution of dose. The ADAPTIVE and SUSAN filters provide the best overall performance, more than halving the dose resolution without significantly distorting the spatial distribution of dose. In summary, this thesis provides new insight into the fundamental nature of PAG density to dose response, develops strategies for minimizing image noise and quantifies system performance and demonstrates that digital image filtering is an effective tool to provide additional improvements to dose resolution.

Hilts, Michelle Louise

36

Methods for visualization of enzymes in polyacrylamide gels.  

PubMed

White bands resulting from precipitation of dodecan-1-ol liberated by hydrolysis of sodium dodecyl sulfate and decan-5-ol released by hydrolysis of decan-5-yl sulfate produced zymograms of the primary and secondary alkylsulfatases from Pseudomonas C(12)B. Gas-liquid chromatographic analyses of ether extracts of the precipitate-containing segments of the zymograms confirmed the identity of the alcohols which were not discerned in extracts of segments of the gels other than those containing precipitates. beta-Galactosidase from Escherichia coli was marked on zymograms by the liberation of o-nitrophenol from o-nitrophenyl-beta-D-galactoside, and arylsulfatase from Pseudomonas C(12)B was marked in gels by liberation of p-nitrophenol from p-nitrophenyl sulfate. Membrane-associated dissimilatory nitrate reductases from a nitrate respirer (Enterobacter aerogenes) and a denitrifier (Pseudomonas perfectomarinus) did not penetrate either 6.8 or 3% polyacrylamide gel but were demonstrable at the top of the gels. In the membrane-bound state, formate served as electron donor for nitrate reductase from E. aerogenes, and reduced nicotinamide adenine dinucleotide (NADH) served as donor for nitrate reductase from P. perfectomarinus. Both enzymes reduced nitrate at the expense of reduced benzyl viologen as well. Assimilatory nitrate reductase from E. aerogenes moved easily into the 6.8% gels (R(f) = 0.43 under the conditions of these experiments). The reduced dye served as electron donor for the assimilatory reductase, but formate and NADH did not. Incubation of the membrane-associated nitrate reductases with 2% Triton X-100 solubilized the enzymes and removed the capacity of formate and NADH to serve as electron donors. Both retained the ability to reduce nitrate at the expense of reduced benzyl viologen. The solubilized dissimilatory reductase from E. aerogenes moved further in the gels (R(f) = 0.49) than the soluble assimilatory reductase; the solubilized dissimilatory reductase from the denitrifier, P. perfectomarinus, moved further in the gels (R(f) = 0.64) than either of the enzymes from E. aerogenes. PMID:4358859

Payne, W J; Fitzgerald, J W; Dodgson, K S

1974-01-01

37

Methods for Visualization of Enzymes in Polyacrylamide Gels  

PubMed Central

White bands resulting from precipitation of dodecan-1-ol liberated by hydrolysis of sodium dodecyl sulfate and decan-5-ol released by hydrolysis of decan-5-yl sulfate produced zymograms of the primary and secondary alkylsulfatases from Pseudomonas C12B. Gas-liquid chromatographic analyses of ether extracts of the precipitate-containing segments of the zymograms confirmed the identity of the alcohols which were not discerned in extracts of segments of the gels other than those containing precipitates. ?-Galactosidase from Escherichia coli was marked on zymograms by the liberation of o-nitrophenol from o-nitrophenyl-?-D-galactoside, and arylsulfatase from Pseudomonas C12B was marked in gels by liberation of p-nitrophenol from p-nitrophenyl sulfate. Membrane-associated dissimilatory nitrate reductases from a nitrate respirer (Enterobacter aerogenes) and a denitrifier (Pseudomonas perfectomarinus) did not penetrate either 6.8 or 3% polyacrylamide gel but were demonstrable at the top of the gels. In the membrane-bound state, formate served as electron donor for nitrate reductase from E. aerogenes, and reduced nicotinamide adenine dinucleotide (NADH) served as donor for nitrate reductase from P. perfectomarinus. Both enzymes reduced nitrate at the expense of reduced benzyl viologen as well. Assimilatory nitrate reductase from E. aerogenes moved easily into the 6.8% gels (Rf = 0.43 under the conditions of these experiments). The reduced dye served as electron donor for the assimilatory reductase, but formate and NADH did not. Incubation of the membrane-associated nitrate reductases with 2% Triton X-100 solubilized the enzymes and removed the capacity of formate and NADH to serve as electron donors. Both retained the ability to reduce nitrate at the expense of reduced benzyl viologen. The solubilized dissimilatory reductase from E. aerogenes moved further in the gels (Rf = 0.49) than the soluble assimilatory reductase; the solubilized dissimilatory reductase from the denitrifier, P. perfectomarinus, moved further in the gels (Rf = 0.64) than either of the enzymes from E. aerogenes. Images

Payne, W. J.; Fitzgerald, J. W.; Dodgson, K. S.

1974-01-01

38

The Application of Polyacrylamide Gel Electrophoresis to the Characterization of Cholinesterase Enzymes Used in Detector Kits.  

National Technical Information Service (NTIS)

Vertical disc gel electrophoresis on polyacrylamide gel tubes has been applied to the separation and identification of cholinesterases from commercially available sources. Cholinesterase from horse serum, bovine erythrocyte, and electric eel was fractiona...

A. Goodman L. M. McCormack H. Martens

1977-01-01

39

Using Ultra-Zoom Gels for High-Resolution Two-Dimensional Polyacrylamide Gel Electrophoresis  

Microsoft Academic Search

\\u000a Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is one of the core Technologies—together with mass spectrometry—of\\u000a proteome research. It is the only method currently available that is able to simultaneously separate the thousands of proteins\\u000a found in biological samples. The method originates from the seminal work of O’Farrell and Klose in the 1970s (1,2). The main drawback of the original method

Sjouke Hoving; Hans Voshol; Jan van Oostrum

40

Simple, Sensitive Zymogram Technique for Detection of Xylanase Activity in Polyacrylamide Gels  

PubMed Central

A method capable of detecting as little as 0.11 U of xylanase activity in polyacrylamide gels was developed. The method entails incubation of protein gels in contact with substrate gels containing unmodified xylan, followed by immersion of substrate gels in 95% ethanol. Resulting zymograms contain transparent bands corresponding to enzymatic activity against an opaque background. Images

Royer, John C.; Nakas, J. P.

1990-01-01

41

Simple, sensitive zymogram technique for detection of xylanase activity in polyacrylamide gels.  

PubMed

A method capable of detecting as little as 0.11 U of xylanase activity in polyacrylamide gels was developed. The method entails incubation of protein gels in contact with substrate gels containing unmodified xylan, followed by immersion of substrate gels in 95% ethanol. Resulting zymograms contain transparent bands corresponding to enzymatic activity against an opaque background. PMID:16348200

Royer, J C; Nakas, J P

1990-06-01

42

Intrinsic Protein Fluorescence Interferes with Detection of Tear Glycoproteins in SDS-Polyacrylamide Gels Using Extrinsic Fluorescent Dyes  

PubMed Central

Intrinsic protein fluorescence may interfere with the visualization of proteins after SDS-polyacrylamide electrophoresis. In an attempt to analyze tear glycoproteins in gels, we ran tear samples and stained the proteins with a glycoprotein-specific fluorescent dye. The fluorescence detected was not limited to glycoproteins. There was strong intrinsic fluorescence of proteins normally found in tears after soaking the gels in 40% methanol plus 1–10% acetic acid and, to a lesser extent, in methanol or acetic acid alone. Nanograms of proteins gave visible native fluorescence and interfere with extrinsic fluorescent dye detection. Poly-L-lysine, which does not contain intrinsically fluorescent amino acids, did not fluoresce.

Zhao, Zhenjun; Aliwarga, Yulina; Willcox, Mark DP

2007-01-01

43

Soybean Inhibitors. Ii. Preparative Electrophoretic Purification of Soybean Proteinase Inhibitors on Polyacrylamide Gel.  

National Technical Information Service (NTIS)

A preparative electrophoretic procedure is described for purifying commercial preparations of two distinct soybean proteinase inhibitors on polyacrylamide gel. One inhibitor, soybean trypsin inhibitor of Kunitz, is obtained in a highly pure state starting...

V. Frattali R. F. Steiner

1968-01-01

44

Characterization of alpha-1-antitrypsin by isoelectric focusing on an ultrathin polyacrylamide gel layer  

Microsoft Academic Search

Through the use of ultrathin layer polyacrylamide gel isoelectric focusing it is possible to obtain a resolution of the bands of a1AT so as to be able to easily recognize all six PiM subtypes. The optimal resolution of the PiM subtypes is obtained without deforming the pattern of the Pi phenotypes. In addition to high resolution, ultrathin layer polyacrylamide gel

G. Massi; A. Fabiano; D. Ragusa; P. Auconi

1979-01-01

45

Electrophoresis for genotyping: microtiter array diagonal gel electrophoresis on horizontal polyacrylamide gels, hydrolink, or agarose.  

PubMed

Electrophoresis of DNA has been performed traditionally in either an agarose or acrylamide gel matrix. Considerable effort has been directed to improved quality agaroses capable of high resolution, but for small fragments, such as those from polymerase chain reaction (PCR) and post-PCR digests, acrylamide still offers the highest resolution. Although agarose gels can easily be prepared in an open-faced format to gain the conveniences of horizontal electrophoresis, acrylamide does not polymerize in the presence of air and the usual configurations for gel preparation lead to electrophoresis in the vertical dimension. We describe here a very simple device and method to prepare and manipulate horizontal polyacrylamide gels (H-PAGE). In addition, the open-faced horizontal arrangement enables loading of arrays of wells. Since many procedures are undertaken in standard 96-well microtiter plates, we have also designed a device which preserves the exact configuration of the 8 x 12 array and enables electrophoresis in tracks following a 71.6 degrees diagonal between wells (MADGE, microtiter array diagonal gel electrophoresis), using either acrylamide or agarose. This eliminates almost all of the staff time taken in setup, loading, and recordkeeping and offers high resolution for genotyping pattern recognition. The nature and size of the gels allow direct stacking of gels in one tank, so that a tank used typically to analyze 30-60 samples can readily be used to analyze 1000-2000 samples. The gels would also enable robotic loading. Electrophoresis allows analysis of size and charge, parameters inaccessible to liquid-phase methods: thus, genotyping size patterns, variable length repeats, and haplotypes is possible, as well as adaptability to typing of point variations using protocols which create a difference detectable by electrophoresis. PMID:7864363

Day, I N; Humphries, S E

1994-11-01

46

Polyacrylamide gel method: synthesis and property of BeO nanopowders  

Microsoft Academic Search

Effects of monomer (AM) concentration, monomer\\/crosslinker (AM\\/MBAM) ratio and salt concentration on the thermal behavior\\u000a of precursor gel and the properties of BeO nanopowder synthesized by polyacrylamide gel method were investigated. The decomposition\\u000a process of precursor gel was also studied. The decomposition process of precursor gel is that, first, the extraction of free\\u000a and crystallized water, and then the thermal

Xiaofeng Wang; Richu Wang; Chaoqun Peng; Tingting Li; Bing Liu

2011-01-01

47

Behaviour of Saccharomyces cerevisiae cells entrapped in a polyacrylamide gel and performing alcoholic fermentation  

Microsoft Academic Search

The behaviour of Saccharomyces cerevisiae cells entrapped in a polyacrylamide gel was studied during their continuous function in an ethanol-producing reactor. Polymerization destroys 40% to 80% of the cells, depending on their physiological state. A three day adaptation phase is required before ethanol production stabilizes and this phase corresponds to an increase in cell concentration in the gels and to

M. H. Siess; C. Divies

1981-01-01

48

Immobilization of DNA in Polyacrylamide Gel for the Manufacture of DNA and DNA–Oligonucleotide Microchips  

Microsoft Academic Search

Activated DNA was immobilized in aldehyde-containing polyacrylamide gel for use in manufacturing the MAGIChip (microarrays of gel-immobilized compounds on a chip). First, abasic sites were generated in DNA by partial acidic depurination. Amino groups were then introduced into the abasic sites by reaction with ethylenediamine and reduction of the aldimine bonds formed. It was found that DNA could be fragmented

Dmitri Proudnikov; Edward Timofeev; Andrei Mirzabekov

1998-01-01

49

Non-denaturing polyacrylamide gradient gel electrophoresis for the diagnosis of dysbetalipoproteinemia  

Microsoft Academic Search

Dysbetalipoproteinemia, an uncommon but highly atherogenic mixed hyperlipidemia due to the accumulation of remnants of triglyceride-rich lipoproteins, is characterized by cholesterol-enriched VLDL that migrates in the ? -position on agarose gels. The demonstration of a broad ? -band on agarose gel electrophoresis of plasma is an insensitive method and ultracentrifugation is an impractical method of diagnosing this condition. Non-denaturing polyacrylamide

Dirk J. Blom; Pamela Byrnes; Sheena Jones; A. David Marais

2003-01-01

50

Internal amino acid sequencing of proteins by in situ cyanogen bromide cleavage in polyacrylamide gels.  

PubMed

A new method was developed for generating peptide fragments for amino acid sequence analysis from polyacrylamide-gel separated proteins. This method involves in situ CNBr treatment of proteins in the polyacrylamide gel after their separation by electrophoresis. Pure CNBr peptides were recovered either by solvent extraction followed by microbore column reversed-phase HPLC or, alternatively, by a second electrophoretic separation step (SDS-PAGE) followed by electrotransfer of the peptides onto polyvinylidene difluoride (PVDF) membranes. These approaches yielded sequence data at subnanomole levels for a wide range of CNBr fragments recovered from gel-separated proteins. PMID:2302197

Jahnen, W; Ward, L D; Reid, G E; Moritz, R L; Simpson, R J

1990-01-15

51

Structural Characterization of templated polyacrylamide gels by small angle X-ray scattering *  

NASA Astrophysics Data System (ADS)

The use of surfactant micelles to template pores into a polyacrylamide gel matrix has been suggested to increase size selectivity of macromolecular separations on them. Various surfactant molecules such as, Sodium dodecyl (laurel) sulfate (SDS), Didodecyldimethyl ammonium bromide (DDAB), Cetyltrimethyl ammonium bromide (CTAB) and, Tetradecyltrimethyl ammonium bromide (TTAB) have been shown to produce templating effects on polyacrylamide and other gels. Small angle X-ray scattering (SAXS) is an excellent tool for investigating the structure of materials. Ideally, analysis of SAXS patterns can reveal the average shape and dimensions of individual micelles, the spacing between them, and the overall structure of the system. Several reports of SAXS measurements of SDS in buffer are available. The system of SDS in polyacrylamide is comparatively new. These systems have been investigated using SAXS, in order to gain some understanding of how the templating process affects the micellar system and the gel matrix. SAXS experiments to elucidate the structure of the micelle/gel systems are reported.

Chakrapani, Mukundan; van Winkle, David H.

2000-03-01

52

Protein extraction from Mycobacterium avium subsp. paratuberculosis: Comparison of methods for analysis by sodium dodecyl sulphate polyacrylamide gel electrophoresis, native PAGE and surface enhanced laser desorption\\/ionization time of flight mass spectrometry  

Microsoft Academic Search

Mycobacterium paratuberculosis causes Johne's disease, a chronic bowel disease in ruminants worldwide and is currently incurable. This study was conducted to compare methods for examining the proteome of M. paratuberculosis. SDS-PAGE, native PAGE and SELDI-TOF-MS were compared and the efficacy of various lysis buffers was assessed. Chaotropic agents (Urea CHAPS and potassium thiocyanate) and non-ionic detergent (Tween20 and Triton X-100)

Sanjeev Gumber; Deborah L. Taylor; Richard J. Whittington

2007-01-01

53

Immobilization of microbial cells using polyvinyl alcohol (PVA) — polyacrylamide gels  

Microsoft Academic Search

A novel cell immobilization technique is developed in which polyvinyl alcohol is crosslinked with boric acid with addition of an acrylamide as a polymerizing agent. The presence of the polymerizing agent overcomes the problem of swelling of PVA gels in aqueous solution. The new immobilization method was used to entrap a phenol-degrading microorganism, a species of Pseudomonas. Phenol was successfully

Wang Jianlong; Hou Wenhua; Qian Yicr

1995-01-01

54

Immobilization of DNA in polyacrylamide gel for the manufacture of DNA and DNA-oligonucleotide microchips.  

SciTech Connect

Activated DNA was immobilized in aldehyde-containing polyacrylamide gel for use in manufacturing the MAGIChip (microarrays of gel-immobilized compounds on a chip). First, abasic sites were generated in DNA by partial acidic depurination. Amino groups were then introduced into the abasic sites by reaction with ethylenediamine and reduction of the aldimine bonds formed. It was found that DNA could be fragmented at the site of amino group incorporation or preserved mostly unfragmented. In similar reactions, both amino-DNA and amino-oligonucleotides were attached through their amines to polyacrylamide gel derivatized with aldehyde groups. Single- and double-stranded DNA of 40 to 972 nucleotides or base pairs were immobilized on the gel pads to manufacture a DNA microchip. The microchip was hybridized with fluorescently labeled DNA-specific oligonucleotide probes. This procedure for immobilization of amino compounds was used to manufacture MAGIChips containing both DNA and oligonucleotides.

Proudnikov, D.; Timofeev, E.; Mirzabekov, A.; Center for Mechanistic Biology and Biotechnology; Engelhardt Inst. of Molecular Biology

1998-05-15

55

Rheology and morphology of pristine graphene/polyacrylamide gels.  

PubMed

Enhancement of toughness in nanomaterial-based hydrogels is a critical metric for many of their engineering applications. Pristine graphene-polyacrylamide (PAM) hydrogels are synthesized via in situ polymerization of acrylamide monomer in PAM-stabilized graphene dispersion. In-situ polymerization leads to the uniform dispersion of the graphene sheets in the hydrogel. The graphene sheets interact with the elastic chains of the hydrogel through physisorption and permit gelation in the absence of any chemical cross-linker. This study represents the first report of pristine graphene as a physical cross-linker in a hydrogel. The properties of the graphene-polymer hydrogel are characterized by rheological measurements and compressive tests, revealing an increase in the storage modulus and toughness of the hydrogels compared to the chemically cross-linked PAM analogues. The physically cross-linked graphene hydrogels also exhibit self-healing properties. These hydrogels prove to be efficient precursors for graphene-PAM aerogels with enhanced electrical conductivity and thermal stability. PMID:23915342

Das, Sriya; Irin, Fahmida; Ma, Lan; Bhattacharia, Sanjoy K; Hedden, Ronald C; Green, Micah J

2013-08-20

56

Rheological monitoring of the formation of polyacrylamide/Cr+3 gels  

SciTech Connect

The formation of polyacrylamide/chromium-ion gels has been followed rheologically. The time dependence of the storage modulus has been used to analyze the kinetics of the gelation process. The kinetic theory of rubber elasticity has been used to determine the crosslink density in the gel from the measured value of the storage modulus. The effects of changing polymer, chromium ion, and reducing agent concentrations have been studied. 30 references.

Prud'Homme, R.K.; Uhl, J.T.; Poinsatte, J.P.; Halverson, F.

1983-10-01

57

Migration of Implants: A Problem with Injectable Polyacrylamide Gel in Aesthetic Plastic Surgery  

Microsoft Academic Search

Polyacrylamide gel (PAAG) has been used as a soft tissue filler material for cosmetic purposes in Europe and China since 1997.\\u000a The various complications of PAAG have been reported. A total of 15 patients who received PAAG injections at other institutions\\u000a were treated for gel migration in the authors’ hospitals. During treatment, the authors found that the injected PAAG had

Ning-xin Cheng; Shi-liang Xu; Hui Deng; Xiao-bang Ding; Xiao-man Zhang; Dai-hong Wu; Hong Zhong; Zi-hong Sun

2006-01-01

58

Assay of plant proteins with bicinchoninic acid for high resolution two-dimensional polyacrylamide gel electrophoresis  

Microsoft Academic Search

A method is described for estimating proteins in the same plant tissue sample that is solubilized for separation by two-dimensional polyacrylamide gel electrophoresis. The method uses a modified bicinchoninic acid (BCA) protein assay procedure and a modified standard urea solubilization buffer to estimate microgram values of unknown protein concentration, in the presence of 9 M urea and 4% Nonidet P-40,

Alan R. Orr; Brett A. Wagner; Catherine T. Howard; Orlando A. Schwartz

1988-01-01

59

Haptoglobin phenotyping by polyacrylamide gel isoelectric focusing and its application to simultaneous typing of serum proteins  

Microsoft Academic Search

A simple isoelectric focusing method for haptoglobin (HP) typing is described. Serum was pretreated first with C. perfringens neuraminidase (CPN) and then with dithiothreitol (DTT). The treated serum was subjected to polyacrylamide gel isoelectric focusing (PAGIF), and the band patterns were detected by immunoblotting. The method could be successfully applied to HP typing of bloodstains as old as 2 months.

M. Fukuda; Y. Tamaki; T. Kishida

1988-01-01

60

Microfluidic 2-D PAGE using multifunctional in situ polyacrylamide gels and discontinuous buffers.  

PubMed

A two-dimensional microfluidic system is presented for intact protein separations combining isoelectric focusing (IEF) and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) employing in situ photopolymerized polyacrylamide (PAAm) gels. The PAAm gels are used for multiple functions. In addition to serving as a highly-resolving separation medium for gel electrophoresis, discrete polyacrylamide gel plugs are used to enable the efficient isolation of different on-chip media including anolyte, catholyte, and sample/ampholyte solutions for IEF. The gel plugs are demonstrated as on-chip reagent containers, holding defined quantities of SDS for on-chip SDS-protein complexation, and enabling the use of a discontinuous buffer system for sample band sharpening during SDS-PAGE. The 2-D chip also employs several unique design features including an angled isoelectric focusing channel to minimize sample tailing, and backbiasing channels designed to achieve uniform interdimensional sample transfer. Separation results using E. coli cell lysate are presented using a 10-channel chip with and without the discontinuous buffer system, with resolving power more than doubled in the former case. Further improvements in separation resolution are demonstrated using a 20-channel chip design. PMID:19190795

Yang, Shuang; Liu, Jikun; Lee, Cheng S; Devoe, Don L

2008-11-19

61

Quantitation of proteins separated in N, N'-1,2-dihydroxyethylenebisacrylamide-crosslinked polyacrylamide gels.  

PubMed

A simple and rapid method for the quantitation of proteins separated either by sodium dodecyl sulfate-electrophoresis or by isoelectric focusing in slab gels is presented. The method is based on the solubility of polyacrylamide gels crosslinked with N, N'-1, 2-dihydroxyethylenebisacrylamide (DHEBA) in periodic acid. After electrophoretic separation proteins are stained with Coomassie brilliant blue G-250. DHEBA gels show considerable swelling during the staining and destaining process but can be shrunk to their normal size in a 10% (w/v) solution of ammonium sulfate. Stained bands are cut from the gel and solubilized in periodic acid. During dissolution the dye decolorizes. Protein concentration in the solution is determined by a modified Coomassie dye-binding assay. Quantitation is linear in the range of 100 ng to 5 micrograms and not disturbed by dissolved gel. Separations in N, N'-1, 2-dihydroxyethylenebisacrylamide-crosslinked gels show qualities similar to those in normal crosslinked gels. PMID:1456419

Neumann, U; Khalaf, H; Rimpler, M

1992-10-01

62

Identification of Frankia Strains by Two-Dimensional Polyacrylamide Gel Electrophoresis  

PubMed Central

Fifteen Frankia strains from five different plant species were analyzed by two-dimensional polyacryl-amide gel electrophoresis to determine their relatedness by comparing the polypeptide patterns obtained. Three major subgroups (A, C, and D) were found in the Alnus-Comptonia-Myrica cross-inoculation group. An isolate from Purshia tridentata had a unique protein pattern and represents a distinct group of frankiae. Members of group A were isolated from root nodules of Alnus incana subsp. rugosa and Alnus viridis subsp. crispa. Group C organisms were from A. incana subsp. rugosa and Comptonia peregrina nodules, and group D organisms were from A. incana subsp. rugosa, A. viridis subsp. cripsa, and Myrica pensylvanica root nodules. Isolates from each gel group were obtained at several widely separated geographical locations. The results indicate that two-dimensional polyacrylamide gel electrophoresis is useful for identifying Frankia isolates. Images

Benson, David R.; Buchholz, S. E.; Hanna, D. G.

1984-01-01

63

Method for the detection and differentiation of cellulase components in polyacrylamide gels  

SciTech Connect

Endoglucanase and exoglucanase components of cellulase can be detected and differentiated after polyacrylamide gel electrophoresis by performing activity stains. Endoglucanase activity was visualized in carboxymethyl cellulose agar replicas of gels by staining with Congo red. General ..beta..-1,4-glucanase activity was located by soaking the gel in a solution of NaBH/sub 4/-reduced cellulo-oligosaccharides, and detecting the formation of reducing sugars by reaction with triphenyl tetrazolium chloride. Endoglucanases are active in both assays, while exoglucanases can be distinguished by their activity in the cellulo-oligosaccharide assay only. This methodology has facilitated the purification and characterization of cellulase components from Trichoderma reesei and Microbispora bispora.

Bartley, T.D.; Murphy-Holland, K.; Eveleigh, D.E.

1984-01-01

64

Proteins of the kidney microvillus membrane. Identification of subunits after sodium dodecylsullphate/polyacrylamide-gel electrophoresis.  

PubMed Central

The proteins of microvilli prepared from pig kidney were analysed by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. The typical pattern stained for protein revealed five major bands, four of which also stained for carbohydrate, and about 15 minor bands. For descriptive purposes the bands were designated numerically by their apparent molecular weights (X10(-3). Well-characterized proteins were identified with four of the five major bands. Dipeptidyl peptidase IV, a serine proteinase that may be specifically labelled with di-isopropyl [32P]phosphorofluoridate, was assigned to band 130. Aminopeptidase M was assigned to band 160, though when released from the membrane by a proteinase, this protein comprises three polypeptides each of lower apparent molecular weight than the native enzyme. Neutral endopeptidase can be assigned to band 95 and actin to band 42. The fifth major band (180) is an extrinsic glycoprotein that has not been identified with any microvillus enzyme activity. These four proteins contribute 21% of the microvillus-membrane protein. Kidney microvillus actin was characterized by a variety of properties and was similar to muscle actin. A computer analysis of the gel pattern indicates that it comprises 9.0% of the microvillus protein. Myosin is not present in the microvillus, but another protein associated with band 95, with properties that distinguish it from neutral endopeptidase, was tentatively identified as alpha-actinin. Alkaline phosphatase was identified as a monomeric polypeptide with an apparent molecular weight of 80000; it is a minor protein of the microvillus and is not discernible as a discrete band in the gel pattern. These and other results permit a model of the organization of the microvillus protein to be suggested. The computer program used has been deposited as Supplementary Publication SUP 50070 (12 pages) at the British Library Lending Division, Boston Spa. Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms given in Biochem. J. (1976) 153,5. Images PLATE 1 PLATE 2

Booth, A G; Kenny, A J

1976-01-01

65

Detection of protein kinase activity by renaturation in sodium dodecyl sulfate-polyacrylamide gels  

SciTech Connect

The authors have developed a procedure for identifying protein kinase activity in protein samples following electrophoresis on SDS-polyacrylamide gels. Proteins are allowed to renature directly in the gel by removal of detergent. The gel is then incubated with (..gamma..-/sup 32/P)ATP to allow renatured protein kinases to autophosphorylate or to phosphorylate various substrates which can be incorporated into the gel. The positions of the radiolabeled proteins can then be detected by autoradiography. With this technique, using purified catalytic subunit of cAMP-dependent protein kinase, enzyme concentrations as low as 0.01 ..mu..g can be detected on gels containing 1.0 mg/ml casein. The procedure is also applicable for the determination of active subunits of multisubunit protein kinases. For example, when the two subunits of casein kinase II are separated by SDS-polyacrylamide gel electrophoresis and allowed to renature, only the larger ..cap alpha.. subunit shows activity. This procedure can also be used to detect and distinguish kinases present in heterogeneous mixtures. Starting with a particulate fraction from LSTRA, a murine T cell lymphoma, several distinct enzymes were detected, including a 30,000 Dalton protein with protein-tyrosine kinase activity. This same enzyme has also been detected in T lymphocytes and other T lymphoid cell lines.

Anostario, M. Jr.; Harrison, M.L.; Geahlen, R.L.

1986-05-01

66

Detection of single sequence repeat polymorphisms in denaturing polyacrylamide sequencing gels by silver staining  

Microsoft Academic Search

Large-scale use of molecular markers in plant breeding is limited by the throughput capacity for genotyping. DNA polymorphisms\\u000a can be detected in denaturing polyacrylamide gels indirectly by nucleotide labeling or directly by staining. Fluorescent-labeling\\u000a or radiolabeling requires sophisticated infrastructure not always available in developing countries. We present an improved\\u000a low-cost method for silver staining and compare it to 2 other

S. Creste; A. Tulmann Neto; A. Figueira

2001-01-01

67

Immobilization of Saccharomyces uvarum cells in porous beads of polyacrylamide gel for ethanolic fermentation  

Microsoft Academic Search

A procedure which does not involve the use of an immiscible organic solvent phase is described for the entrapment of yeast cells in porous beads of polyacrylamide gel. The cells are rapidly dispersed at 4° C in an aqueous solution containing sodium alginate and acrylamide-N,N'methylene-bis-acrylamide monomer, and the suspension is immediately dropped into a solution of calcium formate to give

Archana Pundle; Asmita Prabhune; Hephzibah SivaRaman

1988-01-01

68

Sodium Dodecyl Sulfate-Polyacrylamide Gel Protein Electrophoresis of Freshwater Photosynthetic Sulfur Bacteria  

Microsoft Academic Search

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis (SDS-PAGE) was carried out using different bacterial strains\\u000a of the photosynthetic sulfur bacteria Chlorobium, Thiocapsa, Thiocystis, and Chromatium cultured in the laboratory, and the natural blooms in two karstic lakes (Lake Cisó and Lake Vilar, NE Spain) where planktonic\\u000a photosynthetic bacteria (purple and green sulfur bacteria) massively developed accounting for most of the microbial

M. Begoña Osuna; Emilio O. Casamayor

2011-01-01

69

Plant protein isolation and stabilization for enhanced resolution of two-dimensional polyacrylamide gel electrophoresis  

Microsoft Academic Search

Two-dimensional polyacrylamide gel electrophoresis (2D–PAGE) is the common method of choice for proteomic analysis. By introducing several small changes, a method was developed that not only improved the resolution and reproducibility of 2D–PAGE but also shortened the time of analysis. Precipitation by alkaline phenol and methanol\\/ammonium acetate was the choice for protein extraction. However, instead of precipitating the proteins overnight

Annamraju D. Sarma; Nathan W. Oehrle; David W. Emerich

2008-01-01

70

Viscometric measurement of chromium(III)-polyacrylamide gels by Weissenberg rheogoniometer  

Microsoft Academic Search

Gelled polymers are being used increasingly to modify the movement of injected fluids in secondary and enhanced oil recovery processes. A common gelation process involves the reduction of Cr(VI) to Cr(III) in the presence of polyacrylamide. The Cr(III) reacts or interacts with the polymer to form a gel network. Although correlations of gelation time with principal process variables have been

S. Aslam; S. Vossoughi; G. P. Willhite

1984-01-01

71

A method to quantitate Coomassie blue-stained proteins in cylindrical polyacrylamide gels.  

PubMed

A method for the quantitation of Coomassie blue-stained proteins in cylindrical polyacrylamide gels is described. It involves an elution of the dye with an 80% methanol solution in a sealed Pyrex tube at 100 degrees C for 3 h and a measurement of its concentration at 585 nm. Using a 6.5% polyacrylamide gel and bovine serum albumin as a protein standard, the curve of absorbance of the dye solution as a function of the amount of protein was observed to be linear up to 30-40 micrograms of protein and as little as 0.8-1.0 micrograms of protein could be measured. The validity of the method was indicated by the values obtained for the relative proportions of the human erythrocyte membrane proteins. Using this method, the color yields of several proteins varying widely with respect to their size, amino acid composition, and carbohydrate content were determined in a 6.5% polyacrylamide gel. The results showed that they were generally the same except for proteins having a high carbohydrate content which were significantly lower. PMID:4091255

Wong, P; Barbeau, A; Roses, A D

1985-11-01

72

Ribosomal Ribonucleic Acids of Cultured Cells: a Preliminary Survey of Differences among Mammalian Species Detectable by Polyacrylamide Gel Electrophoresis.  

National Technical Information Service (NTIS)

Ribosomal ribonucleic acids (rRNA's) of cultured cells from various species were compared by polyacrylamide gel electrophoresis. Electrophoretic mobility of the 28 S RNA component varied according to species. Human cell 28 S rRNA was distinguishable from ...

M. E. Soergel F. L. Schaffer

1972-01-01

73

A mobility shift detection method for DNA methylation analysis using phosphate affinity polyacrylamide gel electrophoresis.  

PubMed

We describe a procedure for DNA methylation analysis using the bisulfite-mediated cytosine-to-uracil conversion of a target DNA followed by methylation-specific polymerase chain reaction (MSP) and phosphate affinity polyacrylamide gel electrophoresis (PAGE). The MSP was performed using a 1:1 mixture of 5'-phosphorylated methylation-specific and 5'-OH non-methylation-specific primers. The PAGE using an immobilized phosphate-binding tag molecule (i.e., a polyacrylamide-bound dizinc(II) complex, Zn(2+)-Phos-tag), which selectively captures the 5'-phosphorylated DNA fragment, enabled the mobility shift detection of the methylation-specific product as a slower migration band. Using this novel procedure, we demonstrated the detection of a methylated cytosine base in a pUC19 plasmid. PMID:18394999

Kinoshita-Kikuta, Emiko; Kinoshita, Eiji; Koike, Tohru

2008-03-16

74

A plant dye from Lawsonia inermis for protein staining after polyacrylamide gel electrophoresis.  

PubMed

A reddish-brown dye was isolated from the leaves of Lawsonia inermis by extraction with calcium hydroxide (pH 11-12). A 3.6% crude extract in ethanol/water, 1:1 v/v, was used for direct staining, without fixation, of bovine serum albumin, casein and human serum proteins, following polyacrylamide gel electrophoresis in cylindrical gels. After staining for 30 min the gels were destained for 1/2-2 h with 7% acetic acid at 60 degrees C. Protein staining with Amido Black 10B and Coomassie Brilliant Blue R-250, according to standard protocols, required destaining for 24 h and more to obtain a comparably cleared background. Staining with the plant dye and Coomassie Brilliant Blue had a similar overall staining sensitivity but some minor components of human serum showed different staining characteristics with each of the two dyes. Staining with the plant dye excels over standard staining by speed and simplicity. PMID:1692790

Ali, R; Sayeed, S A

1990-04-01

75

Effects of supercoiling in electrophoretic trapping of circular DNA in polyacrylamide gels.  

PubMed Central

Electrophoretic velocity and orientation have been used to study the electric-field-induced trapping of supercoiled and relaxed circular DNA (2926 and 5386 bp) in polyacrylamide gels (5% T, 3.3% C) at 7.5-22.5 V/cm, using as controls linear molecules of either the same contour length or the same radius of gyration. The circle-specific trapping is reversible. From the duration of the reverse pulse needed to detrap the molecules, the average trap depth is estimated to be 90 A, which is consistent with the molecular charge and the field strengths needed to keep molecules trapped. Trapped circles exhibit a strong field alignment compared to the linear form, and there is a good correlation between the enhanced field alignment for the circles and the onset of trapping in both constant and pulsed fields. The circles do not exhibit the orientation overshoot response to a field pulse seen with linear DNA, and the rate of orientation growth scales as E(-2+/-0.1) with the field, as opposed to E(-1.1+/-0.1) for the linear form. These results show that the linear form migrates by cyclic reptation, whereas the circles most likely are trapped by impalement on gel fibers. This proposal is supported by very similar velocity and orientation behavior of circular DNA in agarose gels, where impalement has been deemed more likely because of stiffer gel fibers. The trapping efficiency is sensitive to DNA topology, as expected for impalement. In polyacrylamide the supercoiled form (superhelical density sigma = -0.05) has a two- to fourfold lower probability of trapping than the corresponding relaxed species, whereas in agarose gels the supercoiled form is not trapped at all. These results are consistent with existing data on the average holes in the plectonemic supercoiled structures and the fiber thicknesses in the two gel types. On the basis of the topology effect, it is argued that impalement during pulsed-field electrophoresis in polyacrylamide gels may be useful for the separation of more intricate DNA structures such as knots. The results also indicate that linear dichroism on field-aligned molecules can be used to measure the supercoiling angle, if relaxed DNA circles are used as controls for the global degree of orientation.

Akerman, B

1998-01-01

76

Polar Residues in Transmembrane Helices can Decrease Electrophoretic Mobility in Polyacrylamide Gels Without Causing Helix Dimerization  

PubMed Central

There are only a few available methods to study lateral interactions and self assembly of transmembrane helices. One of the most frequently used methods is sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) which can report on strong interactions between peptides in SDS solution. Here we offer a cautionary tale about studying the folding and assembly of membrane proteins using peptides and SDS-PAGE experiments as membrane mimetic systems. At least for the specific peptide and detergent systems studied here, we show that a polar asparagine residue in the 12th position of an otherwise hydrophobic helical segment of 20 amino acids causes a peptide to migrate on SDS-PAGE gels with an apparent molecular weight that is twice its true molecular weight, suggesting dimerization. However when examined carefully in SDS solutions and in situ in the polyacrylamide gel itself using Forster resonance energy transfer no interaction can be detected. Instead we show evidence suggesting that differential interactions between peptide and detergent drive the differences in electrophoretic mobility without any interaction between peptides. These results emphasize the need to apply multiple independent techniques to the study of membrane protein folding, and they highlight the usefulness of studying folding and structure of membrane proteins in lipid membranes rather than in detergents.

Walkenhorst, William F.; Merzlyakov, Mikhail; Hristova, Kalina; Wimley, William C.

2010-01-01

77

A rapid 3% polyacrylamide slab gel electrophoresis method for high through put screening of LDL phenotype  

PubMed Central

Background Small dense LDL is reported to be associated with increased coronary artery disease risk by various epidemiological studies. The gold standard for separation and identification of LDL subtypes in plasma is ultracentrifugation which is a lengthy procedure and difficult to perform. Various other methods like NMR, HPLC, gradient gel electrophoresis (GGE) have been reported for LDL sub fractionation all of which require specialized equipments and expertise. We report here a high throughput 3% polyacrylamide slab gel electrophoresis method (PASGE) for sub fractionation of LDL which was compared with GGE, a commonly used method for LDL sub fractionation. Results The 3% PASGE method compared well with the GGE method There was a good correlation between LDL particle diameter identified by the PASGE and GGE (Pearson correlation coefficient = 0.950). A 100% concordance was found when samples were classified as per LDL phenotypes in subjects with A and B phenotype by the two methods with the concordance being 66% in subjects with intermediate (I) phenotype. The electrophoresis apparatus was optimized and designed for running twenty eight samples at a time compared to twelve to fourteen by the conventional PASGE and eight to twelve by disc electrophoresis. Conclusion The rapid 3% polyacrylamide slab gel electrphoresis method developed is simple to perform, cost-effective and can be used for the identification LDL sub fractionation and phenotyping in large epidemiological studies.

Singh, Yogendra; Lakshmy, Ramakrishnan; Gupta, Ruby; Kranthi, Vemparala

2008-01-01

78

Preparation and Shear Modulus of Polyacrylamide Gels as Nerve Cell Culture  

NASA Astrophysics Data System (ADS)

In the recent years, physical interactions between cells and their mechanical environment have been recognized for their influence on cellular functions, such as differentiation, motility, and growth. The importance of this phenomenon on neural cells is being investigated here in order to evaluate the optimal mechanical environment for their maximum growth. We prepared polyacrylamide gel as a culture medium for the nerve cell growth. Since we hypothesize that the shear modulus of the medium, which is fully saturated with water, plays an important role in the cell growth, we prepared gels having different shear modulus by varying the ratio of the polymerizing agents and the thickness of the medium was controlled by molding. It is the key issue to determine the shear modulus of the gels to study the effect of the modulus on the nerve cell growth. However, because the physical properties of the gels should be measured when those are saturated with water, but there should be no water layer on the surface to prevent slip in rheometers, new techniques were developed to dissolve these issues. This poster will present those rheological techniques, preparation of the gels, and the effect of shear modulus of the gel medium on the growth of nerve cells.

Perrault, Cécile M.; Juncker, David; Park, Hee Eon

2008-07-01

79

Accommodating brightness and exposure levels in densitometry of stained polyacrylamide electrophoresis gels  

SciTech Connect

Flatbed scanner densitometers can be operated under various illumination and recording exposure levels. In this work, we show that optical density measurement accuracy, sensitivity, and stability of stained polyacrylamide electrophoresis gel densitometry are crucially dependent on these two factors (brightness and exposure level), notwithstanding that the source is monochromatic, spatially uniform, and the measurements are made using an accurately calibrated step wedge in tandem. We further outline a method to accommodate the intensity deviations over a range of illumination and exposure levels in order to maintain sensitivity and repeatability in the computed optical densities. Comparisons were also made with results from a commercial densitometer.

Tan, Han Yen; Ng, Tuck Wah; Liew, Oi Wah

2010-03-20

80

A visible dye-based staining method for DNA in polyacrylamide gels by ethyl violet.  

PubMed

We describe a visible dye-based staining method for DNA in polyacrylamide gels using ethyl violet (EV). The novel method is a background-free, sensitive, economical, and simple procedure involving only staining and washing steps that can be completed within 30 min. As little as 0.8-1.6 ng of phiX174 DNA/HaeIII can be detected by EV, which is about eightfold more sensitive than Nile blue (NB) stain and twofold less sensitive than ethidium bromide (EB) stain. PMID:20230772

Cong, Wei-Tao; Zhu, Zhong-Xin; He, Hong-Zhang; Jin, Yan; Jiang, Cheng-Xi; Choi, Jung-Kap; Jin, Li-Tai; Li, Xiao-Kun

2010-03-15

81

The use of polyacrylamide gels for mechanical calibration of cartilage — A combined nanoindentation and unconfined compression study  

Microsoft Academic Search

This study investigates polyacrylamide (PA) gel as a calibration material to measure the nanomechanical compressive modulus of cartilage using nanoindentation. Both nanoindentation and unconfined compression testing were performed on PA gel and porcine rib cartilage. The equilibrium moduli measured by the two methods were discernable. Nanoindentation has the advantage of distinguishing between spatially dependent constituent properties that affect tissue mechanical

Cheng Li; Jessica Allen; Tamara Alliston; Lisa A. Pruitt

2011-01-01

82

Identification of Mycobacterium fortuitum, Mycobacterium abscessus, and Mycobacterium borstelense by Polyacrylamide Gel Electrophoresis of Their Cell Proteins  

Microsoft Academic Search

Strains of M. fortuitum, M. abscessus, and M. borstelense showed different polyacrylamide gel electrophoretic patterns of their cell proteins. M. fortuitum strains could easily be distinguished from those of M. abscessus and M. borstelense, and they appear to belong to a single homogeneous group. M. abscessus and M. borstelense gels showed similar patterns, thus tending to confirm recent suggestions that

H. HAAS; J. MICHEL; T. SACKS

83

MALDI analysis of proteins after extraction from dissolvable ethylene glycol diacrylate cross-linked polyacrylamide gels.  

PubMed

Although the extraction of intact proteins from polyacrylamide gels followed by mass spectrometric molecular mass determination has been shown to be efficient, there is room for alternative approaches. Our study evaluates ethylene glycol diacrylate, a cleavable cross-linking agent used for a new type of dissolvable gels. It attains an ester linkage that can be hydrolyzed in alkali conditions. The separation performance of the new gel system was tested by 1D and 2D SDS-PAGE using the outer chloroplast envelope of Pisum sativum as well as a soluble protein fraction of human lymphocytes, respectively. Gel spot staining (CBB), dissolving, and extracting were conducted using a custom-developed workflow. It includes protein extraction with an ammonia-SDS buffer followed by methanol treatment to remove acrylamide filaments. Necessary purification for MALDI-TOF analysis was implemented using methanol-chloroform precipitation and perfusion HPLC. Both cleaning procedures were applied to several standard proteins of different molecular weight as well as 'real' biological samples (8-75 kDa). The protein amounts, which had to be loaded on the gel to detect a peak in MALDI-TOF MS, were in the range of 0.1 to 5 ?g, and the required amount increased with increasing mass. PMID:23775326

Papasotiriou, Dimitrios G; Markoutsa, Stavroula; Gorka, Jan; Schleiff, Enrico; Karas, Michael; Meyer, Bjoern

2013-08-01

84

A user-friendly alternative to formaldehyde-based DNA silver-staining method on polyacrylamide gels.  

PubMed

We have developed a practical, cost-effective and user-friendly protocol to meet the needs of nucleic acids research, particularly in respect of DNA detection on polyacrylamide gels. In this method, the most commonly used alkaline formaldehyde developer in DNA silver stain, which does harm to operator, is first replaced by glucose in alkaline borate buffer. In addition, the effects of six reducing sugars on the quality of DNA visualization were investigated. Consequently, the optimal protocol using glucose takes about 45 min to complete all the procedures, with a detection limit of 5 pg of single DNA band on polyacrylamide gels, was developed. The results indicate that this user-friendly and economic protocol could be a good choice for routine use in DNA visualization on polyacrylamide gels. PMID:20564269

He, Hong-Zhang; Cong, Wei-Tao; Jiang, Cheng-Xi; Pu, Jie; You, Wei-Jing; Gao, Hong-Chang; Zhu, Zhong-Xin; Jin, Li-Tai; Li, Xiao-Kun

2010-07-01

85

Newcastle Disease Virus-Specific RNA: Polyacrylamide Gel Analysis of Single-Stranded RNA and Hybrid Duplexes  

PubMed Central

Newcastle disease virus-specific [3H]uridine-labeled 18S RNA was resolved by polyacrylamide gel electrophoresis into several components with molecular weights from 450,000 to 840,000. The analysis of 35 and 24S virus-specific RNA also revealed several components in each sedimentational class. The conversion of 18S RNA into double-stranded form by hybridization with an excess of unlabeled virion RNA improved the resolution in polyacrylamide gels and revealed at least six distinct components. The same six classes of hybrid duplexes were revealed when 32P-labeled 50S virion RNA was hybridized with an excess of 18S RNA. The applicability of polyacrylamide gel electrophoresis of hybrid duplexes to the analysis of viral genome structure is discussed.

Kaverin, Nicolai V.; Varich, Natalia L.

1974-01-01

86

Model and field studies of the degradation of cross-linked polyacrylamide gels used during the revegetation of slate waste.  

PubMed

Cross-linked polyacrylamide gels are increasingly being used in environmental restoration schemes and horticulture as a means of enhancing water supply to plants. However, the environmental impact of cross-linked polyacrylamide gel deployment in soil remains poorly understood. This study assessed the chemical, physical and biological properties of new and field-conditioned cross-linked polyacrylamide gels. Both monomeric acrylamide (11 microg l(-1)) and acrylic acid (285 microg l(-1)) were observed in new gel; however, the levels of monomers in field-conditioned gels (1-6 years old) were very low (acrylamide <1 microg l(-1); acrylic acid <7 microg l(-1)). Generally, freeze-thaw processes and exposure to UV radiation had little effect on gel acrylic acid and acrylamide concentrations. However, elevated temperatures (35 degrees C) caused a significant release of up to 144 mug l(-1) of acrylamide and 453 microg l(-1) of acrylic acid in new gel and up to 25 microg l(-1) of acrylamide and 157 microg l(-1) of acrylic acid in field-conditioned gels. In contrast, gel water holding capacity was highly dependent upon environmental conditions (UV exposure and freeze/thaw cycles produced the greatest loss of water holding in new gels) and gel age. Optical microscopy revealed that after placement in the field the gels became increasingly colonised over time by fungi and bacteria. In enrichment cultures, we were unable, however, to demonstrate microbial growth when cross-linked polyacrylamide was used as the sole nitrogen source. In summary, under a range of conditions cross-linked polyacrylamide did not release acrylamide above legally permitted limits, with the exception of gel subjected to elevated temperatures. However, their capacity for holding water decreased sharply within 18 months. We therefore conclude that cross-linked polyacrylamide placed in soil is relatively stable with respect to the production of potentially toxic acrylamide, a species with a short half-life, which degrades to the much less toxic acrylic acid. However, the loss of water holding capacity raises questions about its long-term effectiveness in land restoration schemes as this is the main reason it is used in this role. PMID:15589246

Holliman, Peter J; Clark, Jennifer A; Williamson, Julie C; Jones, Davey L

2005-01-01

87

Apolipoprotein distribution in human lipoproteins separated by polyacrylamide gradient gel electrophoresis.  

PubMed

The heterogeneity of serum lipoproteins (excluding very low density (VLDL) and intermediate density (IDL) lipoproteins) and that of lipoproteins secreted by HepG2 cells has been studied by immunoblot analysis of the apolipoprotein composition of the particles separated by polyacrylamide gradient gel electrophoresis (GGE) under nondenaturing conditions. The reactions of antibodies to apoA-I, apoA-II, apoE, apoB, apoD, and apoA-IV have revealed discrete bands of particles which differ widely in size and apolipoprotein composition. GGE of native serum lipoproteins demonstrated that apoA-II is present in lipoproteins of limited size heterogeneity (apparent molecular mass 345,000 to 305,000) and that apoB is present in low density lipoproteins (LDL) and absent from all smaller or denser lipoproteins. In contrast, serum apoA-I, E, D, and A-IV are present in very heterogeneous particles. Serum apoA-I is present mainly in particles of 305 to 130 kDa where it is associated with apoA-II, and in decreasing order of immunoreactivity in particles of 130-90 kDa, 56 kDa, 815-345 kDa, and finally within the size range of LDL, all regions where there is little detectable apoA-II. Serum apoE is present in three defined fractions, one within the size range of LDL, one containing heterogeneous particles between 640 and 345 kDa, and one defined fraction at 96 kDa. Serum apoD is also present in three defined fractions, one comigrating with LDL, one containing heterogeneous particles between 390 and 150 kDa, and one band on the migration front. Most of serum apoA-IV is contained in a band comigrating with albumin. GGE of centrifugally prepared LDL shows the presence of apoB, apoE, and apoD, but not that of apoA-I. However, the particles containing apoA-I, which, in serum, migrated within the LDL size range and as bands of 815 to 345 kDa, were recovered upon centrifugation in the d greater than 1.21 g/ml fraction. GGE of high density lipoproteins (HDL) indicated that most of apoA-I, A-II, and A-IV were present in lipoproteins of the same apparent molecular mass (390-152 kDa). ApoD tended to be associated with large HDL, and this was also significant for HDL apoE, which is present in lipoproteins ranging from 640 to 275 kDa. GGE of very high density lipoproteins (VHDL) presented some striking features, one of which was the occurrence of apolipoproteins in very discrete bands of different molecular mass. ApoA-II was bimodally distributed at 250-175 kDa and 175-136 kDa, the latter fraction also containing apoA-I.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3411236

Vézina, C A; Milne, R W; Weech, P K; Marcel, Y L

1988-05-01

88

Delayed Gel Indurations as an Adverse Effect of Polyacrylamide Filler and Its Easy Treatment  

PubMed Central

Background. The more increasing use of permanent soft tissue fillers such as polyacrylamide hydrogel (PAAG) for aesthetic purposes, the more adverse events resulting from them are reported. Occasionally, nonserious complications and misdiagnosis result in unnecessary surgeries and sequels. Objective. To introduce delayed gel indurations (DGIs) as a late onset complication of PAAG and its easy treatment. Patient and Methods. Twenty patients (17 females and 3 males) referred to us with subcutaneous mass at injected site of PAAG. We diagnosed DGI based on clinical and sonography findings and treatment was performed with a hole by 16-gauge needle and squeezing. Results. From 20 patients with 21 cases of DGI, 5 (23.8%), 5 (23.8%), and 5 (23.8%) cases in cheeks, glabella, and lips were seen, respectively. The time range between PAAG injection and presentation of patients was 10–28 months (mean = 17.5%). All of the patients responded very well to treatment without recurrence and any complications. Conclusion. DGI is a nonserious, late onset, and easily treated complication of PAAG that is probably induced due to water exchange between gel and surrounding tissue and modest host immune reaction to gel.

Kavoussi, Hossein; Ebrahimi, Ali

2012-01-01

89

Setaria digitata in cattle of Thailand identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis.  

PubMed

Adult Thai Setaria worms collected from cattle which were bred, housed and slaughtered in Thailand were morphologically identified as Setaria digitata. Furthermore, in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) adult Thai S. digitata had the same protein profiles as adult Japanese S. digitata, but did not possess the protein with a molecular size of 69 kDa which was confirmed in adult S. marshalli. In addition, there were no differences in the protein profiles between male and female S. digitata. In point of the distribution pattern of the proteins ranging from 73 to 64 kDa revealed by 2D-PAGE, there were no differences between Thai and Japanese S. digitata, and between male and female worms of the species. PMID:10342300

Subhachalat, P; Shirasaka, S; Nakajima, H; Adachi, Y

1999-04-01

90

Polyacrylamide gel electrophoresis analysis of ribosomal protein AT-L30 from an actinomycete genus, Streptosporangium.  

PubMed

We analyzed the ribosomal AT-L30 proteins from 11 type strains of species belonging to the genus Streptosporangium. The electrophoretic mobilities of the AT-L30 preparations from these strains, as determined by two-dimensional polyacrylamide gel electrophoresis, revealed that they could be divided into three groups. The first group contained Streptosporangium viridogriseum, S. viridogriseum subsp. kofuense, and S. albidum, while the second group contained S. roseum, S. album, S. vulgare, S. nondiastaticum, S. fragile, S. violaceochromogenes, and S. amethystogenes. S. corrugatum was a member of the third group. These groups were completely consistent with Nonomura's previous classification, which was based on morphological criteria. The results of partial amino acid sequencing of AT-L30 preparations from several representative strains strongly supported the hypothesis that each of the three groups of the genus Streptosporangium merits separate generic status. PMID:1736963

Ochi, K; Miyadoh, S

1992-01-01

91

Phosphoprotein staining for sodium dodecyl sulfate-polyacrylamide gel electrophoresis using fluorescent reagent morin hydrate.  

PubMed

A fluorescence-based stain with 3,5,7,2',4'-pentahydroxyflavone (morin hydrate, MH) was designed to stain phosphoproteins in one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Al(3+) was applied as a "fixed bridge," providing an efficient energy transfer channel between phosphoprotein and MH, to produce a strong fluorescent complex for the determination of phosphoprotein. As little as 62.5ng of ?-casein (7 or 8 phosphates) and ?-casein (5 phosphates), 125ng of ovalbumin (2 phosphates), and ?-casein (1 phosphate) could be visualized with a wide linear dynamic range. In comparison with conventional methods, MH stain is a time-saving method that takes just 90min. It also has good compatibility with routine protein stainings such as Coomassie Brilliant Blue R (CBBR) and SYPRO Ruby for total protein analysis. PMID:23274386

Wang, Xu; Hwang, Sun-Young; Cong, Wei-Tao; Jin, Li-Tai; Choi, Jung-Kap

2012-12-28

92

Isoelectric focusing--polynucleotide/polyacrylamide-gel electrophoresis. A technique to separate and characterize nuclease activities.  

PubMed Central

Individual native nuclease activities from human leucocytes are separated by using two-dimensional gel electrophoresis in an apparatus that allows the simultaneous running of 28 gels. Proteins are separated by isoelectric focusing in a disc gel, followed by electrophoresis into a slab gel containing DNA. Protein denaturants are avoided in the second dimension by the use of a running pH well above the optimal pH for DNAase (deoxyribonuclease) activity. Electrophoresed gels are incubated in appropriate buffers to activate nuclease activity. After staining for intact DNA, the positions of active enzymes, unobscured by the presence of other proteins, are revealed as colourless spots in a reddish-purple field. The technique is easy to use and is sensitive to 50pg of DNAase I. Versatility is provided by the use of either acidic or basic electrophoresis running buffers and by the use of specific gel incubation conditions to reveal different sets of enzyme activities. Two DNAases active at pH 7.4 in the presence of Mg2+ and Ca2+, and sixteen DNAases active at acidic pH and not requiring metals, are detected. Treatment of the human enzymes with specific glycosidases reveals that many of the human DNAases are glycoproteins containing negatively charged moieties and may be derived from modification of parent activities. Images Fig. 3. Fig. 4. Fig. 5.

Karpetsky, T; Brown, G E; McFarland, E; Brady, S T; Roth, W; Rahman, A; Jewett, P

1984-01-01

93

Separation and identification of DNA-carcinogen adduct conformers by polyacrylamide gel electrophoresis with laser-induced fluorescence detection  

SciTech Connect

The authors have developed a separation protocol utilizing high-resolution polyacrylamide gel electrophoresis (PAGE) to isolate stable anti-benzo[a]pyrene diol epoxide adducts of oligodeoxynucleotides. Both enantiomers produced multiple adduct species. The distribution of adduct types could be quantitated by densitometry of autoradiograms or Cerenkov counting of eluted oligomers modified by anti-BPDE isomers. Laser-induced fluorescence (LIF) spectra of eluted adducts at 4.2 K (fluorescence line-narrowing spectroscopy) and 77 K revealed that bands corresponded to pure conformers of pyrene chromophore. Carcinogen-modified oligodeoxynucleotides were single-stranded, but there were often considerable stacking interactions between the pyrenyl residues and the oligonucleotide bases, indicating that electrophoresed oligomers were single-stranded but in a native, versus random-coil conformation. The ability to identify and quantitate adducts by PAGE-LIF, coupled with the high resolution and sensitivity of both techniques, makes PAGE and LIF in tandem a potentially powerful tool in the study of chemical carcinogenesis or other ligand-DNA interactions. 43 refs., 7 figs., 1 tab.

Marsch, G.A.; Jankowiak, R.; Farhat, J.H.; Small, G.J. (Ames Lab., IA (United States) Iowa State Univ., Ames (United States))

1992-12-01

94

Performing isoelectric focusing and simultaneous fractionation of proteins on a rotary valve followed by sodium dodecyl-polyacrylamide gel electrophoresis.  

PubMed

In this technical note, we design and fabricate a novel rotary valve and demonstrate its feasibility for performing isoelectric focusing and simultaneous fractionation of proteins, followed by sodium dodecyl-polyacrylamide gel electrophoresis. The valve has two positions. In one position, the valve routes a series of capillary loops together into a single capillary tube where capillary isoelectric focusing (CIEF) is performed. By switching the valve to another position, the CIEF-resolved proteins in all capillary loops are isolated simultaneously, and samples in the loops are removed and collected in vials. After the collected samples are briefly processed, they are separated via sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE, the second-D separation) on either a capillary gel electrophoresis instrument or a slab-gel system. The detailed valve configuration is illustrated, and the experimental conditions and operation protocols are discussed. PMID:23819755

Wang, Wei; Lu, Joann J; Gu, Congying; Zhou, Lei; Liu, Shaorong

2013-07-02

95

Improved staining of proteins in polyacrylamide gels including isoelectric focusing gels with clear background at nanogram sensitivity using Coomassie Brilliant Blue G-250 and R-250.  

PubMed

An improved procedure for staining of proteins following separation in polyacrylamide gels is described which utilizes the colloidal properties of Coomassie Brilliant Blue G-250 and R-250. The new method is based on addition of 20% v/v methanol and higher concentrations of ammonium sulfate to the staining solution previously described. The method combines the advantage of much shorter staining time with high sensitivity, a clear background not requiring destaining, stepwise staining, and stable fixation after staining. The method has been applied to staining of polyacrylamide gels after sodium dodecyl sulfate-electrophoresis and isoelectric focusing in carrier ampholyte-generated pH gradients. PMID:2466658

Neuhoff, V; Arold, N; Taube, D; Ehrhardt, W

1988-06-01

96

Staining of proteins on SDS polyacrylamide gels and on nitrocellulose membranes by Alta, a colour used as a cosmetic  

Microsoft Academic Search

We describe here the use of Alta, a pre-existing scarlet-red stain of cosmetic use, for staining proteins on sodium dodecyl sulfate (SDS) polyacrylamide gels, as well as for a single step staining of gels and nitrocellulose membranes during Western blot analysis. This stain, which is composed of 0.8% Crocein scarlet (brilliant crocein) and 0.2% Rhodamine B, is inexpensive, easy to

Jayanta K. Pal; Dhanashri Godbole; Kiran Sharma

2004-01-01

97

One-step purification of R-phycoerythrin from the red macroalga Palmaria palmata using preparative polyacrylamide gel electrophoresis  

Microsoft Academic Search

Phycoerythrin is a major light-harvesting pigment of red algae and cyanobacteria widely used as a fluorescent probe. In this study, phycoerythrin of the red macroalga Palmaria palmata was extracted by grinding the algal sample in liquid nitrogen, homogenisation in phosphate buffer and centrifugation. Phycoerythrin was then purified from this crude extract using preparative polyacrylamide gel electrophoresis (PAGE) with a continuous

A. V. Galland-Irmouli; L. Pons; M. Luçon; C. Villaume; N. T. Mrabet; J. L. Guéant; J. Fleurence

2000-01-01

98

Illustrated Handbook for High Resolution of IAA Oxidase-Peroxidase Isoenzymes by Isoelectric Focusing in Slabs of Polyacrylamide Gel.  

National Technical Information Service (NTIS)

Specific techniques are presented for high resolution of peroxidase-IAA oxidase isoenzymes in polyacrylamide gel slabs by isoelectric focusing in pH gradients. Banding patterns are entirely reproducible. pH gradients are linear and there is no 'cathode sh...

M. C. Hoyle

1978-01-01

99

The characterization of Nigerian varieties of pepper, Capsicum annuum and Capsicum frutescens by SDS polyacrylamide gel electrophoresis of seed proteins  

Microsoft Academic Search

The possibility of using electrophoresis to characterize varieties of pepper, Capsicum annuum and Capsicum frutescens cultivated in Nigeria was investigated. The SDS- polyacrylamide gel electropherogram of extracted total seed proteins of 10 breeding lines in each of the 6 varieties investigated, revealed a pattern in which 12 polypeptide bands with apparent molecular weight range of 22 to 98 kilodaltons could

P. G. C. Odeigah; B. Oboh; I. O. Aghalokpe

1999-01-01

100

Electrophoresis of /sup 35/S-labeled proteoglycans of polyacrylamide-agarose composite gels and their visualization by fluorography  

SciTech Connect

Techniques for the electrophoresis of /sup 35/S-labeled proteoglycans on polyacrylamide-agarose gel slabs and subsequent fixation, impregnation, and fluorography of such electrophoretograms have been developed. The procedure permits the examination of newly synthesized proteoglycan subspecies using a rapid technique, previously unavailable for these labeled molecules.

Carney, S.L.; Bayliss, M.T.; Collier, J.M.; Muir, H.

1986-01-01

101

Imaging findings of breast augmentation with injected hydrophilic polyacrylamide gel: patient reports and literature review.  

PubMed

Hydrophilic polyacrylamide gel (PAAG) is a nonresorbable soft tissue filler that has been used as implant material for breast augmentation in some countries, particularly from the Asian continent. Many complications associated with hydrogel use have been reported in the clinical literature including inflammation, persistent mastodynia, formation of multiple lumps, poor cosmetic results, glandular atrophy, and significant spread of hydrogel into the surrounding tissue. Data on long-term toxicity is currently unavailable. The radiologic features of PAAG injection mammoplasty frequently constitute a diagnostic challenge for radiologists. Indeed, the imaging appearances of uncomplicated PAAG implants may mimic conventional implants on mammography, sonography and MRI, with some distinguishing features. The location and local spread of the injected PAAG, and the eventual detection of local inflammation, are best evaluated by ultrasonography and especially MRI, considered the most sensitive technique for assessment of PAAG mammoplasty. MRI clearly depicts the volume and the distribution of gel within the breast; contrast medium enhancement allows delineation of areas of inflammation and infection. It is important to be familiar with the spectrum of imaging findings in order to make an accurate diagnosis and offer proper management. This paper aims to review the normal and abnormal mammographic, sonographic, and MR imaging characteristics of PAAG augmentation mammoplasty through presented patient reviews of three women having undergone direct PAAG injection. PMID:19836915

Khedher, Najoua Ben; David, Julie; Trop, Isabelle; Drouin, Suzanne; Peloquin, Laurence; Lalonde, Lucie

2009-10-16

102

Microchamber Western blotting using poly-L-lysine conjugated polyacrylamide gel for blotting of sodium dodecyl sulfate coated proteins.  

PubMed

We report a novel strategy to immobilize sodium dodecyl sulfate (SDS)-coated proteins for fully integrated microfluidic Western blotting. Polyacrylamide gel copolymerized with a cationic polymer, poly-L-lysine, effectively immobilizes all sized proteins after sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and enables SDS-PAGE and subsequent immuno-probing in an automated microfluidic chip. Design of a poly-l-lysine conjugated polyacrylamide gel allows optimization of SDS-protein immobilization strength in the blotting gel region of the microchamber. The dependence of protein capture behavior on both the concentration of copolymerized charges and poly-lysine length is studied and gives important insight into an electrostatic immobilization mechanism. Based on analysis of protein conformation, the immobilized proteins bind with partner antibody after SDS dilution. We demonstrate each step of the microchamber Western blot, including injection, separation, transfer, immobilization, blocking, and immunoblot. The approach advances microfluidic protein immunoblotting, which is directly relevant to the widely-used SDS-PAGE based slab-gel Western blot, while saving sample volume, labor, and assay time. PMID:23848185

Chung, Minsub; Kim, Dohyun; Herr, Amy E

2013-08-05

103

Application of Neuhoff's optimized Coomassie brilliant blue G-250/ammonium sulfate/phosphoric acid protein staining to ultrathin polyacrylamide gels on polyester films.  

PubMed

An optimized Coomassie staining procedure, utilizing Coomassie Brilliant Blue G-250 in phosphoric acid/ammonium sulfate, was applied to ultrathin-layer isoelectric focusing in 0.18 mm polyacrylamide gels, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis in 0.38 mm polyacrylamide gels, both backed to Gel-Fix polyester supporting films. After isoelectric focusing staining of gelatin and acidic proteins was better with the phosphoric acid/ammonium sulfate procedure than with conventional organic solvent methods. When applied to gels after sodium dodecyl sulfate-polyacrylamide gel electrophoresis the sensitivity of the phosphoric acid/ammonium sulfate method was equal to that on conventional staining but lower than on silver staining. PMID:2466657

Peisker, K

1988-05-01

104

Microscopic agglutination and polyacrylamide gel electrophoresis analyses of oral anaerobic spirochetes.  

PubMed Central

Microscopic agglutination (MA) analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to determine strain and species similarities and dissimilarities among three species of oral anaerobic spirochetes, Treponema denticola, Treponema pectinovorum, and Treponema vincentii. The MA analysis revealed a diversity of serologic reactivity or sharing of common antigens within each species. However, there was no cross-reactivity or sharing of common antigens among the three species. Distinct SDS-PAGE whole-cell electrophoretograms for each species were obtained. The banding patterns for 16 T. denticola strains revealed 30 distinct proteins, while the banding patterns for 5 strains of T. pectinovorum and 2 strains of T. vincentii revealed 26 and 35 distinct proteins, respectively. Analysis of the electrophoretograms showed that their respective banding patterns could be used to distinguish the three species from one another. In addition, strain differences within each species could be detected. There was a correlation between MA analysis and SDS-PAGE analysis. It is thus suggested that both MA and SDS-PAGE analysis be included in classification schemes for the identification of oral spirochetes. Images

Tall, B D; Nauman, R K

1986-01-01

105

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis of freshwater photosynthetic sulfur bacteria.  

PubMed

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis (SDS-PAGE) was carried out using different bacterial strains of the photosynthetic sulfur bacteria Chlorobium, Thiocapsa, Thiocystis, and Chromatium cultured in the laboratory, and the natural blooms in two karstic lakes (Lake Cisó and Lake Vilar, NE Spain) where planktonic photosynthetic bacteria (purple and green sulfur bacteria) massively developed accounting for most of the microbial biomass. Several extraction, solubilization, and electrophoresis methods were tested to develop an optimal protocol for the best resolution of the SDS-PAGE. Protein composition from different water depths and at different times of the year was visualized within a molecular mass range between 100 and 15 kDa yielding up to 20 different protein bands. Protein banding patterns were reproducible and changed in time and with depth in agreement with changes in photosynthetic bacteria composition. When a taxonomically stable community was followed in time, differences were observed in the intensity but not in the composition of the SDS-PAGE banding pattern. Three environmental variables directly related to the activity of sulfur bacteria (light, oxygen, and sulfide concentrations) had a significant effect on protein banding patterns and explained 33% of the variance. Changes in natural protein profiles of the bacterial blooms agreed with changes in species composition and in the in situ metabolic state of the populations. PMID:20524118

Osuna, M Begoña; Casamayor, Emilio O

2010-06-04

106

Evaluation of the dose enhancement of iodinated compounds by polyacrylamide gel dosimetry  

NASA Astrophysics Data System (ADS)

In this study, polyacrylamide gel (PAG) dosimetry is used to quantitatively assess the efficiency of radiation sensitizers. The local dose enhancement caused by the K-edge absorption of certain atoms such as bromine and iodine can be employed to increase the damage to neighboring molecules and cells. Clonogenic assays can assess the radiation survival of cells to evaluate the efficiency of radiation sensitizers, but this technique requires reliable cell growth in culture media and is time consuming. Our purpose is to use PAG dosimetry to investigate the sensitizing potential of radiation sensitizers such as iodinated compounds. Incorporation of iodinated radiation sensitizers such as NaI and an iodinated contrast agent leads to a quantifiable dose enhancement ratio. When irradiated at low energy (~40 keV), the dose enhancement ratio of the iodinated contrast agent at concentrations of 0.01 (3.5 mg ml-1), 0.05 (6 mg ml-1) and 0.1 (12 mg ml-1) M are 1.16 ± 0.02, 1.39 ± 0.03 and 1.82 ± 0.04, respectively. No dose enhancement was observed when the samples were irradiated with 1.25 MeV gamma photons.

Meesat, Ridthee; Jay-Gerin, Jean-Paul; Khalil, Abdelouahed; Lepage, Martin

2009-10-01

107

Identification of stable plant cystatin/nematode proteinase complexes using mildly denaturing gelatin/polyacrylamide gel electrophoresis.  

PubMed

The biochemical interactions between two cystatins from rice seeds, oryzacystatin I (OCI) and oryzacystatin II (OCII), and the cysteine proteinases from three plant parasitic nematodes, Meloidogyne hapla, M. incognita and M. javanica, were assessed using standard protease assays and mildly denaturing gelatin/polyacrylamide gel electrophoresis (gelatin/PAGE). Activity detected in extracts of preparasitic second-stage larvae (J2) from M. hapla was optimal at pH 5.5 and was inhibited in vitro by the cysteine proteinase inhibitors trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane, hen egg cystatin, OCI, and OCII. As demonstrated by class-specific activity staining, all the activity measured between pH 3.5 and pH 7.5 was accounted for by a major proteinase form, Mhp1, and two minor forms, Mhp2 and Mhp3. Mhps were also detected in extracts and excretions of parasitic J2 and adult females, indicating their continuous expression throughout development of M. hapla, and their possible involvement in the extracellular degradation of proteins. Interestingly, the two plant cysteine proteinase inhibitors OCI and OCII showed different degrees of affinity for the major proteinase form, Mhp1. Both inhibitors almost completely inactivated this proteinase in native conditions but, unlike OCII, OCI conserved a high affinity for Mhp1 during mildly denaturing gelatin/PAGE, showing the differential stabilities of the OCI/Mhp1 and OCII/Mhp1 complexes. In contrast to Mhp1, the major cysteine proteinases detected in the two closely related species M. incognita and M. javanica were strongly inhibited by OCII, while the inhibition of OCI was partly prevented during electrophoresis. This species-related efficiency of plant cystatins against nematode cysteine proteinases could have practical implications when planning their use to control nematodes of the genus Meloidogyne. PMID:8874065

Michaud, D; Cantin, L; Bonadé-Bottino, M; Jouanin, L; Vrain, T C

1996-08-01

108

Silver staining method for DNA in polyacrylamide gels using eriochrome black T as a silver-ion sensitizer.  

PubMed

A sensitive silver staining method using eriochrome black T as a silver-ion sensitizer for DNA detection in polyacrylamide gels was developed. The sensitivity of this staining method was significantly improved by the new silver-ion sensitizer containing a diazo group, which has reducing power. The staining method lasted a total of approximately 15 min following a fixing step for 2 x 20 min. The detection limit of this staining method was 1-4 pg for PhiX174 DNA/HaeIII in both nondenaturing and denaturing polyacrylamide gels. This staining method was especially effective in low-base pair DNA, with a sensitivity that was approximately ten-fold higher than previously published silver staining methods. PMID:16568502

Hwang, Sun-young; Jin, Li-tai; Yoo, Gyurng-soo; Choi, Jung-Kap

2006-05-01

109

Simple, Time-Saving Dye Staining of Proteins for Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis Using Coomassie Blue  

Microsoft Academic Search

A fixation-free and fast protein-staining method for sodium dodecyl sulfate–polyacrylamide gel electrophoresis using Coomassie blue is described. The protocol comprises staining and quick washing steps, which can be completed in 0.5 h. It has a sensitivity of 10 ng, comparable with that of conventional Coomassie Brilliant Blue G staining with phosphoric acid in the staining solution. In addition, the dye

Wei-Hua Dong; Tian-Yun Wang; Fang Wang; Jun-He Zhang

2011-01-01

110

Method for the typing of Clostridium difficile based on polyacrylamide gel electrophoresis of (/sup 35/S)methionine-labeled proteins  

SciTech Connect

A typing method for Clostridium difficile based on the incorporation of (/sup 35/S)methionine into cellular proteins, their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their visualization by autoradiography is described. On analysis of the radiolabeled-protein profiles, nine distinct groups were observed (A to E and W to Z). The method, which is simple, reproducible, and readily expandable, has been applied in epidemiological studies to demonstrate cross-infection and hospital acquisition of C. difficile.

Tabaqchali, S.; O'Farrell, S.; Holland, D.; Silman, R.

1986-01-01

111

Detection of low-molecular weight allergens resolved on two-dimensional electrophoresis with acid–urea polyacrylamide gel  

Microsoft Academic Search

Two-dimensional electrophoresis with immobilized pH gradient (IPG) followed by acetic acid\\/urea–polyacrylamide gel electrophoresis (AU–PAGE) was developed for the detection of low-molecular weight food allergens. Wheat proteins were used to test the applicability of AU–PAGE for the analysis of food allergens. Isoelectric focusing (IEF) for first dimension was performed with IPG pH 3–10. AU–PAGE was performed as a second-dimensional electrophoresis and

Kazumi Kitta; Mayumi Ohnishi-Kameyama; Tatsuya Moriyama; Tadashi Ogawa; Shinichi Kawamoto

2006-01-01

112

Identification of the Porcine Intestinal 1,25-dihydroxyvitamin D3 Receptor on Sodium Dodecyl Sulfate\\/Polyacrylamide Gels by Renaturation and Immunoblotting  

Microsoft Academic Search

Identification of the porcine 1,25-dihydroxyvitamin D3 receptor protein on NaDodSO4\\/polyacrylamide slab gels was accomplished by two separate techniques: (i) assay of the specific binding activity of tritiated 1,25-dihydroxyvitamin D3 to protein eluted from NaDodSO4\\/polyacrylamide gels and renatured and (ii) immunoblotting of the partially purified receptor using two anti-receptor monoclonal antibodies. The porcine receptor preparation used in these studies was isolated

Margaret C. Dame; Eric A. Pierce; Hector F. Deluca

1985-01-01

113

Enhanced removal of detergent and recovery of enzymatic activity following sodium dodecyl sulfate-polyacrylamide gel electrophoresis: UUse of casein in gel wash buffer  

SciTech Connect

The inclusion of 1% casein or bovine serum albumin in buffer used to reactivate enzymes subjected to sodium dodecyl sulfate (SDS)-polyacrylamide electrophoresis resulted in accelerated removal of SDS and restoration of nuclease and beta-galactosidase enzyme activities. Nuclease and beta-galactosidase activities which are absent from gels after longer wash procedures are detectable with this technique. Enzyme activity in gels prepared with SDS which contained inhibitory contaminants was partially restored by the casein wash procedure. The threshold of detection of two-dimensionally separated deoxyribonuclease I using the casein wash procedure was 1 picogram.

McGrew, B.R.; Green, D.M. (Univ. of New Hampshire, Durham (USA))

1990-08-15

114

Simple, time-saving dye staining of proteins for sodium dodecyl sulfate-polyacrylamide gel electrophoresis using Coomassie blue.  

PubMed

A fixation-free and fast protein-staining method for sodium dodecyl sulfate-polyacrylamide gel electrophoresis using Coomassie blue is described. The protocol comprises staining and quick washing steps, which can be completed in 0.5 h. It has a sensitivity of 10 ng, comparable with that of conventional Coomassie Brilliant Blue G staining with phosphoric acid in the staining solution. In addition, the dye stain does not contain any amount of acid and methanol, such as phosphoric acid. Considering the speed, simplicity, and low cost, the dye stain may be of more practical value than other dye-based protein stains in routine proteomic research. PMID:21850222

Dong, Wei-Hua; Wang, Tian-Yun; Wang, Fang; Zhang, Jun-He

2011-08-05

115

Proteome mapping by two-dimensional polyacrylamide gel electrophoresis in combination with mass spectrometric protein sequence analysis  

Microsoft Academic Search

\\u000a The high resolving power of two-dimensional polyacrylamide gel electrophoresis 2D-PAGE and its full analytical and preparative\\u000a potential have been described with special emphasis on reproducibility and standardization of protein spot patterns, enhanced\\u000a protein detection sensitivity, and computer analysis database development. New methodologies for peptide mass fingerprinting,\\u000a peptide, sequence, and fragmention tagging have been highlighted. Major challenges associated with 2D-PAGE\\/mass spectrometric

Ettore Appella; David Arnott; Kazuyasu Sakaguchi; Peter J. Wirth

116

Use of an iridium electrode for direct measurements of pI of proteins after isoelectric focusing in polyacrylamide gel.  

PubMed

The use of an iridium microelectrode 0.5 mm in diameter is proposed for measuring the pH gradient in polyacrylamide gels after isoelectric focusing. The electrode exhibits a perfectly linear potential/pH relationship; thus it can be used directly in conjunction with a pH meter using the pH scale for readings. pH equilibrium values are rapidly reached (10-15 s) and pI determinations are obtainable with good accuracy (better than 0.1 pH). PMID:11823

Papeschi, G; Bordi, S; Beni, C; Ventura, L

1976-11-26

117

Characterization of ribosomal proteins from different tissues and species of animals by electrophoresis on polyacrylamide gel  

Microsoft Academic Search

Summary Proteins from ribosomes of different tissues and animals were characterized by polyacrylamide disc electrophoresis. The proteins from ribosomes of different tissues from the same animal are qualitatively similar. The results of the experiments with ribosomes from the livers of different species of animals exhibit clear differences, in the electrophoretic patterns of the proteins.

H. Bielka; H. Welfle

1968-01-01

118

A Review of the Partly Hydrolyzed Polyacrylamide Cr(III) Acetate Polymer Gels  

Microsoft Academic Search

Enhanced oil recovery techniques and optimization of the oil field operations are currently of great importance for the oil and gas industry, which has an aggressive approach to research and technological modernization in order to supply the demand for conventional oil. The versatility of partly hydrolyzed polyacrylamide Cr(III) acetate has placed it as one of the most widely used polymer

S. M. Vargas-Vasquez; L. B. Romero-Zerón

2008-01-01

119

Metachromatic staining patterns of basic proline-rich proteins from rat and human saliva in sodium dodecyl sulfate-polyacrylamide gels  

Microsoft Academic Search

A series of basic proteins, rich in proline, were isolated from the salivary secretions of humans and rats. These proteins underwent metachromasia after staining with Coomassie brilliant blue R-250 in sodium dodecyl sulfate-polyacrylamide gels. The technique of destaining gels in several changes of 10% acetic acid after a 30-min staining period is a rapid method of general utility for the

M. G. Humphreys-Beher; D. J. Wells

1984-01-01

120

Isoelectric focusing of human parotid salivary proteins in hybrid carrier ampholyte-immobilized pH gradient polyacrylamide gels.  

PubMed

Isoelectric focusing of human salivary proteins with carrier ampholyte-isoelectric focusing systems requires prior desalting and concentration of samples, a procedure which is time-consuming and requires relatively large volumes of samples. By contrast, immobilized pH gradient gels are more tolerant to salt loads. Thus pretreatment of samples consists only of centrifugation prior to isoelectric focusing. If larger loads (greater than 50 micrograms) are required, the samples may be concentrated by lyophilization and reconstitution in a smaller volume of water or by dialysis against 30% w/v polyethylene glycol. Immobilized pH gradient polyacrylamide gels (incorporating a hybrid carrier ampholyte system) of two pH ranges (pH 4-9 and pH 3.5-5.0) have been used to separate the proteins in human parotid saliva. The effects of urea on focused patterns were studied; in pH 4-9 gels it gave improved resolution of protein bands, whereas in pH 3.5-5.0 gels it prevented protein precipitation. The salivary proteins were then visualized by staining with Coomassie Brilliant Blue G-250 or a silver procedure. Using the latter, 25-30 well-resolved bands were formed on a pH 4-9 gel loaded with 20 micrograms of proteins. The method offers considerable advantages compared with carrier ampholyte-isoelectric focusing. PMID:1697536

Khoo, K S; Beeley, J A

1990-06-01

121

Effect of heat and sodium dodecyl sulfate on solubilization of proteins before two-dimensional polyacrylamide gel electrophoresis.  

PubMed

To solubilize biological samples, sodium dodecyl sulfate (SDS) frequently is added and the mixture heated at 70-100 degrees C. However, two-dimensional polyacrylamide gel electrophoresis of a single protein after SDS treatment has not been reported. When rabbit-muscle creatine kinase was so run, we saw considerable difference in the gel staining pattern for the heated and nonheated enzyme dissolved in the SDS solution. After heating for 10 min at 95 degrees C the number of silver-stained spots apparent increased, and staining of several spots intensified. After 60 min, most of the discrete spots disappeared. Evidently the peptide backbone had been hydrolyzed. When the enzyme was simply left at room temperature for four days, the effects were similar. Appearance of new spots and loss of spots apparently are caused by heating alone but are intensified by SDS. Experiments with human serum albumin yielded similar results. PMID:6499173

Hodges, S C; Hirata, A A

1984-12-01

122

Detection of metalloproteins in human liver cytosol by synchrotron radiation X-ray fluorescence after sodium dodecyl sulphate polyacrylamide gel electrophoresis  

Microsoft Academic Search

An improved method of analysis of metals in protein bands with synchrotron radiation X-ray fluorescence (SRXRF) after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation is introduced and applied to human liver cytosol. Through a step of drying the gel before SRXRF determination, the continuous background resulting mainly from the Compton-scattering of X-rays by the gel matrix was substantially reduced, and

Yuxi Gao; Chunying Chen; Peiqun Zhang; Zhifang Chai; Wei He; Yuying Huang

2003-01-01

123

Thin-layer chromatography and polyacrylamide gel electrophoresis-based assays for sialyltransferases using tetramethylrhodamine-labeled acceptors.  

PubMed

Two novel assay systems for the determination of sialyltransferase activity using a tetramethylrhodamine-labeled disaccharide Galbeta1-4GlcNAc (2) as the acceptor are described. The TMR-labeled disaccharide 2 was synthesized by directly coupling Galbeta1-4GlcNAc-O-(CH(2))(6)NH(2) (1) with 5-tetramethylrhodamine N-hydroxysuccinimide ester. The K(m) value for compound 2 obtained with alpha-2,6-sialyltransferase from rat liver (EC 2.4.99.1) was 160 +/- 20 microM. After incubation of compound 2 with sialyltransferase the product and the unreacted acceptor substrate were separated either by thin-layer chromatography (TLC) on C-18 silica gel plates or by polyacrylamide gel electrophoresis (PAGE). The density of the spots on the TLC plates and the fluorescence of the bands on the gel were quantified. The assay conditions were optimized using crude bovine colostrum extract and also alpha-2, 6-sialyltransferase from rat liver. The detection limits for the TLC and PAGE assays were 1 and 0.4 microU of the rat liver enzyme, respectively. Either assay allows the parallel investigation of several samples at a time and is useful for the testing of fractions during enzyme purification. PMID:10998267

Hubl, U; Slim, G C; Zubkova, O V

2000-10-01

124

Allergens in hymenoptera venoms. X. Vespid venoms versus venom sac extracts: comparison by two-dimensional polyacrylamide gel electrophoresis.  

PubMed

Vespid venoms were compared to venom sac extracts by two-dimensional polyacrylamide gel electrophoresis using non-equilibrium pH gradient electrophoresis in the first dimension and sodium dodecyl sulfate electrophoresis in the second. The gels were stained with silver. Fresh venoms from four species, Vespula maculifrons, Polistes fuscatus fuscatus, P. metricus and P. exclamans, were compared with commercially available venom sac extracts from the same species. In each case the venom sac extract contained all of the proteins detected in the fresh venom plus numerous additional proteins which are probably sac components. Yellow jacket and bee (Apis mellifera) proteins were extracted from the gels and tested for IgE binding activity using pooled sera from RAST-positive individuals. Significant IgE binding activity was found for the five known bee allergens and for the major yellow jacket venom proteins. Fresh pure vespid venoms contain a relatively small number of major protein subunits. Venom sac extracts contain the same components plus many other proteins not found in the pure venoms. PMID:6625227

Wood, C L; Timmons, B E; Hoffman, D R

1983-10-01

125

Protein concentration of cerebrospinal fluid by precipitation with Pyrogallol Red prior to sodium dodecyl sulphate-polyacrylamide gel electrophoresis.  

PubMed

The Pyrogallol Red Molybdate (PRM) and Coomassie Brilliant Blue (CBB) protein dye-binding assays have been applied to samples of cerebrospinal fluid (CSF) to investigate protein concentration by dye precipitation prior to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein concentration values of the CSF samples (N=62) showed good agreement between the PRM and CBB assays as indicated by linear regression analysis (y(PRM)=1.033x(CBB)+1.004 in units of mg/l, r=0.99) but the PRM assay was optimal for protein concentration as the PRM protein-dye complex was less soluble allowing protein recovery over a wider working range. Dye precipitation using PRM is recommended as a simple, rapid and economic method for protein concentration of samples of CSF prior to SDS-PAGE. PMID:11245891

Williams, K M; Marshall, T

2001-02-26

126

Silver staining of extensively glycosylated proteins on sodium dodecyl sulfate-polyacrylamide gels: enhancement by carbohydrate-binding dyes.  

PubMed

Two methods are described for detecting less than 1 microgram of highly glycosylated proteins, such as mucins, on sodium dodecyl sulfate-polyacrylamide gels. They combine commonly employed periodic acid-Schiff (PAS) and Alcian blue dyes with silver stain. Carbohydrate prestaining renders mucins more cationic and favors greater complexation with ionic silver. Comparisons of different mucin samples stained either with PAS-silver or alcian blue-silver indicate differential staining between the two techniques. Such differences may, in part, be due to an affinity of Alcian blue for sulfated glycoproteins. These two staining protocols when used in conjunction with silver staining alone are particularly valuable for assessing sample purity and for detecting contaminating proteins during mucin purification protocols. PMID:1692672

Jay, G D; Culp, D J; Jahnke, M R

1990-03-01

127

Comparison of the influence of inorganic salts on the NMR dose sensitivity of polyacrylamide-based gel dosimeter  

NASA Astrophysics Data System (ADS)

On the NMR dose sensitivities of polyacrylamide-based gel dosimeters irradiated by X-ray, the additive effect of various inorganic salts (electrolytes) is investigated. Among the various combination of cations (Li+, Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Zn2+ and Al3+) and anions (Cl-, NO-3 and SO2-4), MgCl2 is shown to be the most effective sensitizer. In the result, it is suggested that the extent of the increase of the dose sensitivity may correlate to the hydration power of cations rather than anions. Contrary to the dose sensitivity enhancement, the depression of melting point caused by the additives is also pointed out.

Hayashi, S.-I.; Kawamura, H.; Usui, S.; Tominaga, T.

2013-06-01

128

Disaggregation of adenylate cyclase during polyacrylamide-gel electrophoresis in mixtures of ionic and non-ionic detergents  

PubMed Central

1. Adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] solubilized from the rat liver plasma membrane with 1% Lubrol PX and partially purified by gel filtration in buffer containing 0.01% Lubrol PX was physically characterized by polyacrylamide-gel electrophoresis. 2. The molecular radius determined for the partially purified enzyme was 4.9nm, compared with the value of 3.9nm obtained for the enzyme before gel filtration. 3. This difference, representing an approximate doubling of the molecular volume of the enzyme, implied that aggregation with itself or other proteins had occurred during partial purification. 4. Aggregation was not reversed by electrophoresis in the presence of high Lubrol concentrations. 5. Substitution of deoxycholate or N-dodecylsarcosinate for Lubrol PX either for solubilization or during electrophoresis led to poorer resolution of membrane proteins at concentrations giving greater than 70% loss of enzyme activity. 6. Partially purified adenylate cyclase was electrophoresed in the presence of mixed micelles of Lubrol PX and deoxycholate or Lubrol PX and N-dodecylsarcosinate. Different mixtures were examined simultaneously in a suitable apparatus. 7. Electrophoresis in the presence of 0.1% Lubrol plus 0.03% deoxycholate decreased the molecular radius of the cyclase to 4.0nm, with greater than 90% recovery of enzymic activity. The net charge of the enzyme was also increased, indicating ionic detergent binding. 8. With 0.1% Lubrol plus 0.03% N-dodecylsarcosinate the molecular radius was 4.3nm, recovery approx. 50% and net charge similar to that seen in Lubrol plus deoxycholate. 9. The resolution of cyclase from bulk protein, on an analytical scale, was improved in the presence of detergent mixtures, as compared with resolution in Lubrol alone. 10. The results demonstrate the usefulness of polyacrylamide-gel electrophoresis to detect and overcome aggregation problems with membrane proteins and suggest that detergent mixtures in specific ratios may be useful in the purification of adenylate cyclase and other intrinsic membrane proteins. ImagesFig. 3.

Newby, Andrew C.; Chrambach, Andreas

1979-01-01

129

Routine diagnosis with PhastSystem compared to conventional electrophoresis: automated sodium dodecyl sulfate-polyacrylamide gel electrophoresis, silver staining and western blotting of urinary proteins.  

PubMed

The recent introduction of the PhastSystem, an automatic electrophoresis and staining system with precast gradient-gels, allows rapid and reproducible analysis of proteinuria in patients suffering from renal injury. A routine method for sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis (SDS-PAGE) and silver staining of unconcentrated urine specimens in the PhastSystem is described and compared to our conventional "macro"-method with self-cast SDS-polyacrylamide gradient gels. The method described for the PhastSystem using 0.3 microL sample volumes and an 8-25% polyacrylamide gradient gel leads to highly reproducible results within 1.5 h. Before electrophoresis urine specimens were neither concentrated nor dialyzed. Samples with a protein concentration exceeding 5 mg/mL had to be diluted 1:5 (v/v). Analysis and documentation of PhastGels appeared as easy as with our conventional SDS-PAGE. Protein bands could reliably be identified by Western blotting. Urine and serum proteins, separated in PhastGels, were electrophoretically transferred to nitrocellulose and detected with specific antibodies against human albumin, transferrin, alpha-1-antitrypsin and IgG. Comparison of several standard kits for molecular weight determination revealed considerable differences concerning the quality of protein separation patterns. Availability of precast gels and automatization of SDS-PAGE and staining allows easy standardization of urine SDS-PAGE among clinical routine laboratories. PMID:2469571

Scherberich, J E; Fischer, P; Bigalke, A; Stangl, P; Wolf, G B; Haimerl, M; Schoeppe, W

1989-01-01

130

Normoxic polyacrylamide gel doped with iodine: response versus X-ray energy.  

PubMed

The basis of Synchrotron Stereotactic Radio-Therapy (SSRT) is the incorporation of high atomic number atoms (iodine, for example) into the tumour mass followed by an irradiation with a monochromatic, low energy, X-ray beam from a synchrotron source. The purpose of the present study was to determine whether polymer gel dosimetry could be used to measure the enhancement of absorbed energy induced by the iodine in the media. We have used a standard nPAG formulation, loaded with NaI and the irradiations were performed either with monochromatic X-rays at the ESRF medical beamline or with a conventional 6 MV X-ray beam from a linear accelerator at the Grenoble University Hospital. We observed sensitivity increase with iodine loaded gels irradiated at low energies, in good agreement with the theoretical iodine dose-enhancement. As expected, the response of the iodine-doped polymer gel was not increased after irradiation with mega-voltage X-rays. We demonstrate in this study that polymer gel dosimeters can be used for measuring dose-enhancement due to iodine presence in SSR treatment. PMID:18602237

Gastaldo, Jérôme; Boudou, Caroline; Lamalle, Laurent; Troprès, Irène; Corde, Stéphanie; Sollier, Albéric; Rucka, Günther; Elleaume, Hélène

2008-07-03

131

Solution NMR of proteins within polyacrylamide gels: Diffusional properties and residual alignment by mechanical stress or embedding of oriented purple membranes  

Microsoft Academic Search

The diffusive properties of biomacromolecules within the aqueous phase of polyacrylamide gels are described. High quality NMR spectra can be obtained under such conditions. As compared to water, a fivefold reduction in the translational diffusion constant, but only a 1.6-fold decrease (1.4-fold increase) in amide-15N T2 (T1) are observed for human ubiquitin within a 10% acrylamide gel. Weak alignment of

Hans-Jürgen Sass; Giovanna Musco; Stephen J. Stahl; Paul T. Wingfield; Stephan Grzesiek

2000-01-01

132

A modified coomassie brilliant blue G 250 staining method for the detection of chitinase activity and molecular weight after polyacrylamide gel electrophoresis.  

PubMed

A modified Coomassie Brilliant Blue G 250 staining method for detecting chitinolytic enzymes in chitin-containing polyacrylamide gel electrophoresis (PAGE) is presented. The staining formed achromatic zones at the locations of the migrated enzyme. Using Streptomyces griseus chitinase, we have demonstrated that our method is more sensitive and less complicated than the conventional Calcofluor white M2R staining. PMID:18691542

Liau, Chun Yi; Lin, Chung-Sheng

2008-07-01

133

Chiral discrimination of amines by anisotropic NMR parameters using chiral polyacrylamide-based gels.  

PubMed

A new chiral alignment medium for dimethyl sulfoxide, methanol, and water as solvents was developed. Because both enantiomers of the gel are available, it is possible to enantiodiscriminate natural products such as strychnine HCl that naturally occurs as single enantiomer. With the two methods of achieving anisotropy, namely stretching and confinement, the degree of alignment can be adjusted, and the director changed from horizontal to vertical. This increases the applicability. Three compounds were enantiodiscriminated on the basis of residual dipolar coupling data: mefloquine HCl, strychnine HCl, and menthylamine HCl. PMID:23280659

Schmidt, Manuel; Sun, Han; Leonov, Andrei; Griesinger, Christian; Reinscheid, Uwe M

2012-12-01

134

Fast fluorescent staining of protein in sodium dodecyl sulfate polyacrylamide gels by palmatine.  

PubMed

A fast and sensitive protein fluorescent detection method in SDS-PAGE using the natural product palmatine is described. Palmatine is an alkaloid found in various plants exhibiting a broad spectrum of antibiotic activity in humans. The sensitivity of palmatine staining is similar to those of the SYPRO Red, SYPRO Tangerine, and SYPRO Orange protein gel stains - about 4 ng per protein band. This detection sensitivity is comparable to colloidal CBB staining. Since proteins stained with palmatine do not need destaining, the staining procedure can be easily shortened and completed in about 30 min. Stained proteins can be photographed using a UV transilluminator. The results of the present study suggest that the palmatine staining is sensitive, rapid, low cost, and safe for a broad application to the research of protein. PMID:18081205

Cong, Wei-Tao; Jin, Li-Tai; Hwang, Sun-Young; Choi, Jung-Kap

2008-01-01

135

Fast and sensitive colloidal coomassie G-250 staining for proteins in polyacrylamide gels.  

PubMed

Coomassie Brilliant Blue (CBB) is a dye commonly used for the visualization of proteins separated by SDS-PAGE, offering a simple staining procedure and high quantitation. Furthermore, it is completely compatible with mass spectrometric protein identification. But despite these advantages, CBB is regarded to be less sensitive than silver or fluorescence stainings and therefore rarely used for the detection of proteins in analytical gel-based proteomic approaches. Several improvements of the original Coomassie protocol(1) have been made to increase the sensitivity of CBB. Two major modifications were introduced to enhance the detection of low-abundant proteins by converting the dye molecules into colloidal particles: In 1988, Neuhoff and colleagues applied 20% methanol and higher concentrations of ammonium sulfate into the CBB G-250 based staining solution(2), and in 2004 Candiano et al. established Blue Silver using CBB G-250 with phosphoric acid in the presence of ammonium sulfate and methanol(3). Nevertheless, all these modifications just allow a detection of approximately 10 ng protein. A widely fameless protocol for colloidal Coomassie staining was published by Kang et al. in 2002 where they modified Neuhoff's colloidal CBB staining protocol regarding the complexing substances. Instead of ammonium sulfate they used aluminum sulfate and methanol was replaced by the less toxic ethanol(4). The novel aluminum-based staining in Kang's study showed superior sensitivity that detects as low as 1 ng/band (phosphorylase b) with little sensitivity variation depending on proteins. Here, we demonstrate application of Kang's protocol for fast and sensitive colloidal Coomassie staining of proteins in analytical purposes. We will illustrate the quick and easy protocol using two-dimensional gels routinely performed in our working group. PMID:19684561

Dyballa, Nadine; Metzger, Sabine

2009-08-03

136

An improved plant leaf protein extraction method for high resolution two-dimensional polyacrylamide gel electrophoresis and comparative proteomics.  

PubMed

We report here a simple and universally applicable protocol for extracting high quality proteins from plant leaf tissues. The protocol provides improved resolution and reproducibility of two-dimensional polyacrylamide gel electrophoresis (2-DE) and reduces the time required to analyze samples. Partitioning rubisco by polyethylene glycol (PEG) fractionation provides clearer detection of low-abundance proteins. Co-extraction of interfering substances increases the sample conductivity, which results in poor electrophoretic separation. Re-extraction of PEG-fractionated samples with phenol effectively eliminated interfering substances, which results in optimal conductivity during separation in the first dimension of the isoelectric focusing. Smooth focusing reduces analysis time and provides superior resolution in 2-DE gels. Incubating the samples at -80° C instead of -20° C reduced protein precipitation time to 2-3 h. Removal of nonprotein contaminants and the use of sonication increased protein solubility without additional reagents. These changes enabled loading and separation of maximum amounts of proteins, which permitted improved protein identification by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). An immunological approach revealed that little or no ribulose-1, 5-bisphosphte bisphosphate carboxylase oxygenase was present in the PEG supernatant. In addition, low-abundance proteins, such as myelocytomatosis transcription factor (MYC) and alpha subunit of heterotrimeric guanine nucleotide-binding protein complex (G?), were detected only in the modified PEG supernatant and not in the total protein. These results suggest that our protocol produced high quality proteins and made many low-abundant proteins available for proteomic analysis. The successful application of this protocol for analyzing the leaf proteomes of soybean, Miscanthus sinensis, barley, Chinese cabbage, peanut and tea (Camellia sinensis) suggests that it could be used for comparative proteomic analysis of a wide range of plant leaves. PMID:23072551

Alam, I; Sharmin, Sa; Kim, K-H; Kim, Y-G; Lee, Jj; Lee, B-H

2012-10-17

137

Separation of radiolabelled protein from brain and spinal cord of spinal hemisected rats on SDS polyacrylamide slab gels.  

PubMed

After hemisection of the spinal cord in rats, alterations in amino acid incorporation into protein have been observed in brain and spinal cord. Proteins mediating these changes have been studied in the present experiment. Male, Long-Evans hooded rats were given either a laminectomy and dura incision (sham) at spinal segment T2, a left spinal cord hemisection, or no operative procedures. One hour prior to utilization at 1, 3 and 14 days postoperation, amimals were injected subcutaneously with 200 microCi of [3H]-L-lysine and 200 microCi of [3H]-L-amino acid mixture. Samples were prepared for electrophoresis and proteins separated on linear gradient SDS polyacrylamide slab gels (7.5-20% acrylamide). The Gel slabs were cut into slices and processed for scintillation counting. In right somatomotor cortex, there was evidence for a general stimulation of amino acid incorporation at one day postoperation in animals which received surgery. At other postoperation intervals, significant increases in proteins in the regions of 90-150,000, 50-65,000 and 35-45,000 molecular weight (MW) were observed. In spinal cord, significant increases in proteins in the regions of 55-65,000, 30-45,000 and 15,000 MW were observed over postoperation time in all animals receiving surgery compared to normals. A large, significant increase in the radioactivity of proteins in the region of 18-20,000 MW were observed in the spinal cord lesion site of spinal hemisected animals alone at three days postoperation. These results indicate that increases in amino acid incorporation into the brain and spinal cord of laminectomized and spinal hemisected animals observed previously are theresult of both specific and nonspecific changes in protein incorporation of precursors. PMID:6770100

Wells, M R

1980-01-01

138

Cyanogen bromide cleavage of proteins in sodium dodecyl sulphate/polyacrylamide gels. Diagonal peptide mapping of proteins from epidermis.  

PubMed Central

A two-dimensional electrophoretic procedure employing CNBr has been devised for the analysis of proteins in sodium dodecyl sulphate/polyacrylamide gels. The technique allows the detection of an unusual class of epidermal proteins that lack methionine. The proteins have been identified by this method in newborn mouse, rat, and rabbit, because they are stable in the presence of CNBr and consequently lie on a diagonal. Adult human epidermis also contains CNBr-stable proteins, but in lesser amounts than in the newborn rabbit or newborn rodents. The methionine-containing proteins (i.e., the keratins) are degraded by CNBr into a series of unique and characteristics peptides which lie below the diagonal. Inter- and intra-species similarities and differences exist between the individual keratins, depending on the number and distribution of their methionine residues. The peptide-map patterns for the rodent and lagomorph proteins are more similar to each other than to that for the human proteins. The maps for rat and rabbit skin proteins are the most similar. We conclude that the epidermal keratins are a closely related, yet individually distinct, group of proteins that are found in conjunction with a class of proteins that lack methionine. The latter proteins are related to the histidine-rich basic protein, an epidermal structural protein that aggregates with keratin filaments. Images Fig. 1. Fig. 2.

Lonsdale-Eccles, J D; Lynley, A M; Dale, B A

1981-01-01

139

In-gel staining of proteins in native poly acryl amide gel electrophoresis using tetrakis(4-sulfonato phenyl)porphyrin.  

PubMed

Protein identification in polyacrylamide gel electrophoresis (PAGE) requires post-electrophoretic steps like fixing, staining and destaining of the gel, which are time-consuming and cumbersome. We have developed a method for direct visualization of protein bands in PAGE using tetrakis(4-sulfonato phenyl)porphyrin (TPPS) as a dye without the need for any post electrophoretic steps, where separation and recovery of enzymes become much easier for further analysis. Activity staining was done to prove that the biochemical activity of the enzymes was preserved after electrophoresis. PMID:21233569

Divakar, Kalivarathan; Sujatha, Vijayan; Barath, Sridhar; Srinath, Krishnamurthy; Gautam, Pennathur

2011-01-01

140

Allelic variation of the HMW glutenin subunits in Aegilops tauschii accessions detected by sodium dodecyl sulphate (SDS-PAGE), acid polyacrylamide gel (A-PAGE) and capillary electrophoresis  

Microsoft Academic Search

Summary Variability of high molecular weight glutenin subunits (HMW-GS) was studied in 198 accessions of Ae. tauschii (2n=2x=14, DD) by sodium dodecyl sulphate (SDS-PAGE) and acid polyacrylamide gel electrophoresis (A-PAGE) and capillary electrophoresis (CE). A high allelic variation of HMW-GS, including some novel x- and y-type subunits and variable subunit combinations were observed. One accession (TD159) showed a x-type null

Yueming Yan; S. L. K. Hsam; Jianzhong Yu; F. J. Zeller

2003-01-01

141

Analysis of the Gc polymorphism in human populations by isoelectrofocusing on polyacrylamide gels. Demonstration of subtypes of the Gc 1 allele and of additional Gc variants  

Microsoft Academic Search

For the study of the group-specific component (Gc) system, serum samples were examined by polyacrylamide gel electrophoresis and by a newly developed immunofixation isoelectrofocusing procedure. Thereby, a greater extent of polymorphic variation was revealed than was known previously. The allele Gc1 could be subdivided into the alleles Gc1F and Gc1S. The distribution of Gc1 subtypes was very different in three

J. Constansl; M. Viau; H. Cleve; G. Jaeger; J. C. Quilici; M. J. Palisson

1978-01-01

142

Lithium Dodecyl Sulfate\\/Polyacrylamide Gel Electrophoresis of Thylakoid Membranes at 4 degrees C: Characterizations of Two Additional Chlorophyll A-Protein Complexes  

Microsoft Academic Search

Lithium dodecyl sulfate\\/polyacrylamide gel electrophoresis of Chlamydomonas reinhardtii thylakoid membranes at room temperature gave two chlorophyll-protein complexes, CP I and CP II, as had been reported previously. However, when the electrophoresis was performed at 4 degrees C, there was an increase in the amount of chlorophyll associated with CP I and CP II, and in addition, three other chlorophyll-protein complexes

Philippe Delepelaire; Nam-Hai Chua

1979-01-01

143

Use of benzyldimethyl-n-hexadecylammonium chloride ("16-BAC"), a cationic detergent, in an acidic polyacrylamide gel electrophoresis system to detect base labile protein methylation in intact cells.  

PubMed

A discontinuous polyacrylamide gel system operating at pH 4.0-1.5 which resolves proteins bearing base labile groups extracted from intact cells is described. It uses potassium phosphate buffer in the running and stacking gel and glycine as the trailing ion component. Proteins are solubilized with urea and benzyldimethyl-n-hexadecylammonium chloride, a cationic detergent. The utility of the system is illustrated by fluorographs of the pattern of protein methylation in blood platelets and the HL60 promyelocyte cell line. PMID:6625164

Macfarlane, D E

1983-07-15

144

Dried polyacrylamide gel absorption: a method for efficient elimination of the interferences from SDS-solubilized protein samples in mass spectrometry-based proteome analysis.  

PubMed

Sample preparation holds an important place in MS-based proteome analysis. For effective proteolysis and MS analysis, it is essential to eliminate the interferences while extracting the analytes of interest from complex mixtures. To address this, herein we describe a new dried polyacrylamide gel absorption method. In this method, the protein sample prepared using high concentration of SDS was directly and completely absorbed by vacuum-dried polyacrylamide gel, and then the interfering substances including SDS and some other salts were efficiently removed by in-gel washing steps while retaining the denatured proteins in the gel, thus offering a clean environment amenable to downstream buffer exchange, proteolytic digestion and digest recovery, etc. In combination with in-gel digestion and LC-MS/MS, the newly developed method was applied to the proteome analyses of membrane-enriched fraction and whole tissue homogenate. It was demonstrated that the method is suitable for the analysis of a complex biological sample and can be widely used for sample cleanup in shotgun proteome analyses. PMID:21064138

Zhou, Jian; Li, Jianglin; Li, Jianjun; Chen, Ping; Wang, Xianchun; Liang, Songping

2010-12-01

145

Two-dimensional polyacrylamide gel electrophoresis of equine seminal plasma proteins and their relation with semen freezability.  

PubMed

The objective was to evaluate protein profiles of equine seminal plasma using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and to determine whether any of these proteins were related to semen freezability. Seminal plasma was collected from 10 stallions, of high and low semen freezability, housed at the State Stud of Lower Saxony, and routinely used in AI programs. Twenty-five protein spots were identified from the two-dimensional gel (12%), seven of which were present in all samples (all proteins were identified by MALDI-MS). Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been used to generate ion images of samples in one or more mass-to-charge (m/z) values, providing the capability of mapping specific molecules to two-dimensional coordinates of the original sample. Of the 25 proteins identified, two spots had greater relative content (P < 0.05) in seminal plasma samples collected from stallions with high semen freezability: spot 5 (80-85 kDa, isoelectric point [pI] 7.54), identified as CRISP-3; and spot 45 (18.2 kDa, pI 5.0-5.2), identified as HSP-2. Conversely, protein content was greater (P < 0.05) in seminal plasma samples from stallions with low semen freezability: spot 7 (75.4 kDa, pI 6.9-7.4), identified as lactoferrin; spot 15 (26.7 kDa, pI 5.51), identified as kallikrein; spot 25 (25 kDa, pI 7.54), identified as CRISP-3; and spot 35 (13.9 kDa, pI 3.8-4.2), identified as HSP-1. In conclusion, there were differences in the seminal plasma protein profile from stallions with high and low semen freezability. Furthermore, CRISP-3 and HSP-2 were potential seminal plasma markers of high semen freezability. PMID:21601917

Jobim, M I M; Trein, C; Zirkler, H; Gregory, R M; Sieme, H; Mattos, R C

2011-05-23

146

Blue-native PAGE in plants: a tool in analysis of protein-protein interactions  

Microsoft Academic Search

Intact protein complexes can be separated by apparent molecular mass using a standard polyacrylamide gel electrophoresis system combining mild detergents and the dye Coomassie Blue. Referring to the blue coloured gel and the gentle method of solubilization yielding native and enzymatically active protein complexes, this technique has been named Blue-Native Polyacrylamide Gel-Electrophoresis (BN-PAGE). BN-PAGE has become the method of choice

Holger Eubel; Hans-Peter Braun; A Harvey Millar

2005-01-01

147

High Resolution Clear Native Electrophoresis for In-gel Functional Assays and Fluorescence Studies of Membrane Protein Complexes  

Microsoft Academic Search

Clear native electrophoresis and blue native electro- phoresis are microscale techniques for the isolation of membrane protein complexes. The Coomassie Blue G-250 dye, used in blue native electrophoresis, interferes with in-gel fluorescence detection and in-gel catalytic ac- tivity assays. This problem can be overcome by omitting the dye in clear native electrophoresis. However, clear native electrophoresis suffers from enhanced protein

Ilka Wittig; Michael Karas; Hermann Schagger

2007-01-01

148

Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis Protein Banding Patterns among Rhizobium leguminosarum biovar phaseoli Strains Isolated from the Mexican Bean Phaseolus coccineus  

PubMed Central

Several rhizobial strains were isolated from Phaseolus coccineus root nodules and were determined to be Rhizobium leguminosarum biovar phaseoli strains after reinfection of the same host plant. These strains were characterized by cultural procedures (growth on different carbon sources and intrinsic antibiotic resistance) and electrophoretic procedures (sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total proteins). Our results showed that these rhizobia are very similar to each other, especially in their electrophoretic protein banding patterns, suggesting that they might belong to isolated populations. Images

Arredondo-Peter, R.; Escamilla, E.

1993-01-01

149

Allelic variation of the HMW glutenin subunits in Aegilops tauschii accessions detected by sodium dodecyl sulphate (SDS-PAGE), acid polyacrylamide gel (A-PAGE) and capillary electrophoresis  

Microsoft Academic Search

Variability of high molecular weight glutenin subunits (HMW-GS) was studied in198 accessions of Ae. Tauschii (2n=2x=14, DD) by sodium dodecyl sulphate(SDS-PAGE) and acid polyacrylamide gel electrophoresis (A-PAGE) and capillary electrophoresis\\u000a (CE). A high allelic variation of HMW-GS, including some novel x- and y-type subunits and variable subunit combinations were\\u000a observed. One accession(TD159) showed a x-type null form. The results by

Yueming Yan; S. L. K. Hsam; Jianzhong Yu; Yi Jiang; F. J. Zeller

2003-01-01

150

Fluid diversion and sweep improvement with chemical gels in oil recovery processes. [Four types of gels: resorcinol-formaldehyde; colloidal silica; Cr sup 3+ (chloride)-xanthan; and Cr sup 3+ (acetate)-polyacrylamide  

SciTech Connect

The objectives of this project were to identify the mechanisms by which gel treatments divert fluids in reservoirs and to establish where and how gel treatments are best applied. Several different types of gelants were examined, including polymer-based gelants, a monomer-based gelant, and a colloidal-silica gelant. This research was directed at gel applications in water injection wells, in production wells, and in high-pressure gas floods. The work examined how the flow properties of gels and gelling agents are influenced by permeability, lithology, and wettability. Other goals included determining the proper placement of gelants, the stability of in-place gels, and the types of gels required for the various oil recovery processes and for different scales of reservoir heterogeneity. During this three-year project, a number of theoretical analyses were performed to determine where gel treatments are expected to work best and where they are not expected to be effective. The most important, predictions from these analyses are presented. Undoubtedly, some of these predictions will be controversial. However, they do provide a starting point in establishing guidelines for the selection of field candidates for gel treatments. A logical next step is to seek field data that either confirm or contradict these predictions. The experimental work focused on four types of gels: (1) resorcinol-formaldehyde, (2) colloidal silica, (3) Cr{sup 3+}(chloride)-xanthan, and (4) Cr{sup 3+}(acetate)-polyacrylamide. All experiments were performed at 41{degrees}C.

Seright, R.S.; Martin, F.D.

1992-09-01

151

Continuous monitoring of enzymatic activity within native electrophoresis gels: application to mitochondrial oxidative phosphorylation complexes.  

PubMed

Native gel electrophoresis allows the separation of very small amounts of protein complexes while retaining aspects of their activity. In-gel enzymatic assays are usually performed by using reaction-dependent deposition of chromophores or light-scattering precipitates quantified at fixed time points after gel removal and fixation, limiting the ability to analyze the enzyme reaction kinetics. Herein, we describe a custom reaction chamber with reaction medium recirculation and filtering and an imaging system that permits the continuous monitoring of in-gel enzymatic activity even in the presence of turbidity. Images were continuously collected using time-lapse high-resolution digital imaging, and processing routines were developed to obtain kinetic traces of the in-gel activities and analyze reaction time courses. This system also permitted the evaluation of enzymatic activity topology within the protein bands of the gel. This approach was used to analyze the reaction kinetics of two mitochondrial complexes in native gels. Complex IV kinetics showed a short initial linear phase in which catalytic rates could be calculated, whereas Complex V activity revealed a significant lag phase followed by two linear phases. The utility of monitoring the entire kinetic behavior of these reactions in native gels, as well as the general application of this approach, is discussed. PMID:22975200

Covian, Raul; Chess, David; Balaban, Robert S

2012-09-10

152

Fast protein staining in sodium dodecyl sulfate polyacrylamide gel using counter ion-dyes, Coomassie brilliant blue R-250 and neutral red.  

PubMed

A fast and sensitive protein staining method in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using both an acidic dye, Coomassie Brilliant Blue R-250 (CBBR) and a basic dye, Neutral Red (NR) is described. It is based on a counter ion-dye staining technique that employs oppositely charged two dyes to form an ion-pair complex. The selective binding of the free dye molecules to proteins in an acidic solution enhances the staining effect of CBBR on protein bands, and also reduces gel background. It is a rapid staining procedure, involving fixing and staining steps with short destaining that are completed in about 1 h. As the result, it showed two to fourfold increase in sensitivity comparing with CBBR staining. The stained protein bands can be visualized at the same time of staining. PMID:12433209

Choi, Jung-Kap; Yoo, Gyurng-Soo

2002-10-01

153

Separation of metalloproteins using a novel metal ion contaminant sweeping technique and detection of protein-bound copper by a metal ion probe in polyacrylamide gel electrophoresis: distribution of copper in human serum.  

PubMed

A polyacrylamide gel electrophoresis (PAGE)-based method has been developed, consisting of two types of gel electrophoresis, to obtain an accurate distribution of protein-bound metal ions in biological samples. First, proteins are separated by PAGE without the uptake of contaminant metal ions in the separation field and dissociation of metal ions from the proteins. This is followed by another PAGE for the separation and detection of protein-bound metal ions in small volume samples with high sensitivity in the ppt range using a fluorescent metal probe. The former is a new technique using blue-native (BN) PAGE to electrophoretically sweep all metal contaminants by employing two kinds of chelating agents. These agents form complexes with contaminants in the gel and the separation buffer solution, which migrate towards opposite pole directions, thus lowering the contaminants to below the ppt level during separation. This is termed "Metal Ion Contaminant Sweeping BN-PAGE (MICS-BN-PAGE)". After the separation of proteins under these first metal-free conditions, the metal ions in the gel fractions are eluted, followed by derivatization of copper ions into the metal probe complexes to be separated and determined by fluorescence detection in the second PAGE. In this PAGE-based method, the copper ions bound to ceruloplasmin and superoxide dismutase were quantitatively determined, in addition to the exchangeable albumin-bound copper ions. This system successfully provided distribution maps of protein-copper in human serum. The precise distribution of copper in human serum was investigated, and found to be different from that which is widely accepted. PMID:23964357

Saito, Shingo; Kawashima, Mitsuyoshi; Ohshima, Hiroki; Enomoto, Kazuki; Sato, Makoto; Yoshimura, Hajime; Yoshimoto, Keitaro; Maeda, Mizuo; Shibukawa, Masami

2013-08-20

154

Characterization of the aerosol produced by infrared femtosecond laser ablation of polyacrylamide gels for the sensitive inductively coupled plasma mass spectrometry detection of selenoproteins  

NASA Astrophysics Data System (ADS)

A 2D high repetition rate femtosecond laser ablation strategy (2-mm wide lane) previously developed for the detection of selenoproteins in gel electrophoresis by inductively coupled plasma mass spectrometry was found to increase signal sensitivity by a factor of 40 compared to conventional nanosecond ablation (0.12-mm wide lane) [G. Ballihaut, F. Claverie, C. Pécheyran, S. Mounicou, R. Grimaud and R. Lobinski, Sensitive Detection of Selenoproteins in Gel Electrophoresis by High Repetition Rate Femtosecond Laser Ablation-Inductively Coupled Plasma Mass Spectrometry, Anal. Chem. 79 (2007) 6874-6880]. Such improvement couldn't be explained solely by the difference of amount of material ablated, and then, was attributed to the aerosol properties. In order to validate this hypothesis, the characterization of the aerosol produced by nanosecond and high repetition rate femtosecond laser ablation of polyacrylamide gels was investigated. Our 2D high repetition rate femtosecond laser ablation strategy of 2-mm wide lane was found to produce aerosols of similar particle size distribution compared to nanosecond laser ablation of 0.12-mm wide lane, with 38% mass of particles < 1 µm. However, at high repetition rate, when the ablated surface was reduced, the particle size distribution was shifted toward thinner particle diameter (up to 77% for a 0.12-mm wide lane at 285 µm depth). Meanwhile, scanning electron microscopy was employed to visualize the morphology of the aerosol. In the case of larger ablation, the fine particles ejected from the sample were found to form agglomerates due to higher ablation rate and then higher collision probability. Additionally, investigations of the plasma temperature changes during the ablation demonstrated that the introduction of such amount of polyacrylamide gel particles had very limited impact on the ICP source (? T~ 25 ± 5 K). This suggests that the cohesion forces between the thin particles composing these large aggregates were weak enough to have negligible impact on the ICPMS detection.

Claverie, Fanny; Pécheyran, Christophe; Mounicou, Sandra; Ballihaut, Guillaume; Fernandez, Beatriz; Alexis, Joël; Lobinski, Ryszard; Donard, Olivier F. X.

2009-07-01

155

Fluorographic detection of tritiated glycopeptides and oligosaccharides separated on polyacrylamide gels: analysis of glycans from Dictyostelium discoideum glycoproteins  

SciTech Connect

Previous workers have shown that oligosaccharides and glycopeptides can be separated by electrophoresis in buffers containing borate ions. However, normal fluorography of tritium-labeled structures cannot be performed because the glycans are soluble and can diffuse during equilibration with scintillants. This problem has been circumvented by equilibration of the gel with 2,5-diphenyloxazole (PPO) prior to electrophoresis. The presence of PPO in the gel during electrophoresis does not alter mobility of the glycopeptides and oligosaccharides. After electrophoresis, the gel is simply dried and fluorography performed. This allows sensitive and precise comparisons of labeled samples in parallel lanes of a slab gel and, since mobilities are highly reproducible, between different gels. The procedure is preparative in that after fluorography the gel bands can be quantitatively eluted for further study, without any apparent modification by the procedure. In this report, the procedure is illustrated by fractionation of both neutral and anionic glycopeptides produced by the cellular slime mold Dictyostelium discoideum.

Prem Das, O.; Henderson, E.J.

1986-11-01

156

Study of yeast mitochondrial tRNAs by two-dimensional polyacrylamide gel electrophoresis: characterization of isoaccepting species and search for imported cytoplasmic tRNAs.  

PubMed Central

By two-dimensional polyacrylamide gel electrophoresis, yeast mitochondrial tRNA is fractionated into 27 major species. All but 6 of them migrate distinctly from cytoplasmic tRNAs. Migration of mitochondrial DNA-coded mitochondrial tRNAs shows the occurence of only one cytoplasmic tRNA in mitochondria. Several mitochondrial tRNA spots are identified on the electrophoregrams, some of them show isoaccepting species (Val, Ser, Met, Leu). It is suggested that there are sufficient mitochondrial tRNA genes on yeast mitochondrial DNA to allow mitochondrial protein biosynthesis by the mitochondrial tRNAs alone. Guanosine + Cytidine content and rate base composition are reported for some individual species. Mitochondrial tRNAPhe lacks Ribothymidine. Images

Martin, R P; Schneller, J M; Stahl, A J; Dirheimer, G

1977-01-01

157

Antibody response to epitopes of chlamydial major outer membrane proteins on infectious elementary bodies and of the reduced polyacrylamide gel electrophoresis-separated form.  

PubMed Central

Approximately 60% of the outer membrane of chlamydial elementary bodies (EBs) consists of the major outer membrane protein (MOMP) that has structural and metabolic functions. The antigenic properties of MOMPs from mammalian strains of serovars 1 and 2 and an avian strain of Chlamydia psittaci were analyzed. Polyclonal-monospecific antisera (PMAs), one monoclonal antibody (MAb), and polyclonal antisera (PAs) were produced against reduced polyacrylamide gel electrophoresis-separated MOMPs and against infectious EBs. Three PMAs and the MAb, which were induced by reduced polyacrylamide gel electrophoresis-separated MOMPs, reacted strongly in Western blot (immunoblot) assays with MOMPs of serovar 1 and 2 strains as well as with that of the avian strain 6BC, and two of these PMAs reacted weakly (dilution, 1:20) with the MOMP of strain LGV-2. The third PMA and the MAb against the MOMP of the serovar 2 strain did not react with the MOMP of LGV-2. Four PAs were produced against infectious EBs of the serovar 1 strain. One of these PAs reacted with the homologous MOMP and that of the avian strain 6BC but did not recognize MOMPs of other chlamydial strains. Three of the PAs reacted with MOMPs of homologous strains only and failed to recognize MOMPs of avian, serovar 2, and LGV-2 strains. Five PAs induced against infectious EBs of the serovar strain 2 reacted only with the MOMPs of the homologous strains and failed to recognize MOMPs of other strains of chlamydiae. Consequently, MOMPs of C. psittaci strains possess genus-, species-, and serovar-specific epitopes whereby the immune response to serovar-specific epitopes of MOMP predominate when infectious EBs are used for immunization. Images

Baghian, A; Shaffer, L; Storz, J

1990-01-01

158

Modified method for peptide mapping of collagen chains using cyanogen bromide-cleavage of protein within polyacrylamide gels.  

PubMed

A highly efficient method for cyanogen bromide (CNBr)-mapping of collagen peptides is described. This method was developed based on polypeptide cleavage by CNBr within gel slices according to Barsh et al. [1981) Collagen Relat. Res. 1, 543-548). The proposed method has the following advantages: (i) Analysis of both radiolabeled and unlabeled collagens is possible; (ii) CNBr-cleavage of polypeptides is performed in gel pieces which contain individual bands; (iii) The peptide losses are minimized, offering a more complete analysis of collagens including the low molecular weight CNBr-peptides. PMID:2742127

Sokolov, B P; Sher, B M; Kalinin, V N

1989-02-01

159

High resolution clear native electrophoresis for in-gel functional assays and fluorescence studies of membrane protein complexes.  

PubMed

Clear native electrophoresis and blue native electrophoresis are microscale techniques for the isolation of membrane protein complexes. The Coomassie Blue G-250 dye, used in blue native electrophoresis, interferes with in-gel fluorescence detection and in-gel catalytic activity assays. This problem can be overcome by omitting the dye in clear native electrophoresis. However, clear native electrophoresis suffers from enhanced protein aggregation and broadening of protein bands during electrophoresis and therefore has been used rarely. To preserve the advantages of both electrophoresis techniques we substituted Coomassie dye in the cathode buffer of blue native electrophoresis by non-colored mixtures of anionic and neutral detergents. Like Coomassie dye, these mixed micelles imposed a charge shift on the membrane proteins to enhance their anodic migration and improved membrane protein solubility during electrophoresis. This improved clear native electrophoresis offers a high resolution of membrane protein complexes comparable to that of blue native electrophoresis. We demonstrate the superiority of high resolution clear native electrophoresis for in-gel catalytic activity assays of mitochondrial complexes I-V. We present the first in-gel histochemical staining protocol for respiratory complex III. Moreover we demonstrate the special advantages of high resolution clear native electrophoresis for in-gel detection of fluorescent labeled proteins labeled by reactive fluorescent dyes and tagged by fluorescent proteins. The advantages of high resolution clear native electrophoresis make this technique superior for functional proteomics analyses. PMID:17426019

Wittig, Ilka; Karas, Michael; Schägger, Hermann

2007-04-09

160

Preliminary studies on the role and reactions of tetrakis(hydroxymethyl)phosphonium chloride in polyacrylamide gel dosimeters  

NASA Astrophysics Data System (ADS)

A major source of dosimetric inaccuracy in normoxic polymer gel dosimeters is local variations in the concentration of oxygen scavenger. Currently, a phosphorus compound, tetrakis(hydroxymethyl)phosphonium chloride (THPC), is the oxygen scavenger of choice in most polymer gel dosimetry studies. Reactions of THPC in a gel dosimeter are not limited to oxygen. It can possibly be consumed in reacting with gelling agent, water free-radicals and polymer radicals before, during and after irradiation, hence affecting the dose response of the dosimeter in several ways. These reactions are not fully known or understood. It is our hypothesis that THPC not only scavenges radical species but also modifies the morphology of the gelatin network and of the polymer, possibly by intervening in the polymerization of monomers. These hypotheses are investigated in an anoxic acrylamide-based gel dosimeter. Scanning electron microscopy results indicate gelatin pores decreasing from 70 to 40 µm and a very different radiation-induced polymer structure in samples containing THPC; Fourier-transform Raman spectroscopy shows a two-fold reduction in the dose constants of monomer consumption; however, a significant change in the relative dose constants of monomer consumption as a function of dose could not be detected.

Sedaghat, Mahbod; Bujold, Rachel; Lepage, Martin

2012-10-01

161

Preliminary studies on the role and reactions of tetrakis(hydroxymethyl)phosphonium chloride in polyacrylamide gel dosimeters.  

PubMed

A major source of dosimetric inaccuracy in normoxic polymer gel dosimeters is local variations in the concentration of oxygen scavenger. Currently, a phosphorus compound, tetrakis(hydroxymethyl)phosphonium chloride (THPC), is the oxygen scavenger of choice in most polymer gel dosimetry studies. Reactions of THPC in a gel dosimeter are not limited to oxygen. It can possibly be consumed in reacting with gelling agent, water free-radicals and polymer radicals before, during and after irradiation, hence affecting the dose response of the dosimeter in several ways. These reactions are not fully known or understood. It is our hypothesis that THPC not only scavenges radical species but also modifies the morphology of the gelatin network and of the polymer, possibly by intervening in the polymerization of monomers. These hypotheses are investigated in an anoxic acrylamide-based gel dosimeter. Scanning electron microscopy results indicate gelatin pores decreasing from 70 to 40 µm and a very different radiation-induced polymer structure in samples containing THPC; Fourier-transform Raman spectroscopy shows a two-fold reduction in the dose constants of monomer consumption; however, a significant change in the relative dose constants of monomer consumption as a function of dose could not be detected. PMID:22964826

Sedaghat, Mahbod; Bujold, Rachel; Lepage, Martin

2012-09-11

162

Analysis of proteins copurifying with the cd4\\/lck complex using one-dimensional polyacrylamide gel electrophoresis and mass spectrometry: comparison with affinity-tag based protein detection and evaluation of different solubilization methods  

Microsoft Academic Search

Mass spectrometry-based identification of the components of affinity purified protein complexes after polyacrylamide gel electrophoresis\\u000a (PAGE) and in-gel digest has become very popular for the detection of novel protein interactions. As an alternative, the entire\\u000a protein complex can be subjected to proteolytic cleavage followed by chromatographic separation of the peptides. Based on\\u000a our earlier report of a method using affinity

Oliver K. Bernhard; Anthony L. Cunningham; Margaret M. Sheil

2004-01-01

163

Light Scattering Induced Giant Red-Shift in Photoluminescence from CdTe Quantum Dots Encapsulated in Polyacrylamide Gel Nanospheres  

NASA Astrophysics Data System (ADS)

The photoluminescence emission from CdTe quantum dots embedded in hydrogel nanospheres based on poly(N-isopropylacrylamide) (PNIPAM) polymer is observed to be modified by the random light scattering within the colloidal medium. Photoluminescence emission from CdTe quantum dots of various size has been observed making the gel fluorescent. The optical properties of the quantum dots entrapped within the gel microspheres can be modified due to change in refractive index, volume density of the surrounding hydrogel medium. A red-shift of ˜100 nm has been observed from quantum dots emitting in the green wavelength region as the cell length is increased. This shift is due to secondary scattering and energy transfer induced by the larger scattering cross-section within the medium which results in a re-excitation of larger sized quantum dots.

Garner, Brett W.; Cai, Tong; Hu, Zhibing; Kim, Moon; Neogi, Arup

2009-07-01

164

Large-scale muLC-MS/MS for silver- and Coomassie blue-stained polyacrylamide gels.  

PubMed

2-DE combined with LC-MS/MS has become a routine, reliable protein separation and identification technology for proteome analysis. The demand for large-scale protein identifications after 2-DE separation requires a sensitive and high-throughput LC-MS/MS method. In this report, a simple, splitless, fully automated capillary LC-MS/MS system was described for the large-scale identification of proteins from gels stained with either silver or CBB. The gel samples were digested and peptides were extracted using an in-gel digestion workstation. The peptides were automatically introduced into a capillary column by an autosampler connected to an HPLC pump. A nanoLC pump was then used to deliver the gradient and elute the peptides from the capillary column directly into an LCQ IT mass spectrometer. Neither a peptide trapping setting nor a flow split is needed in this simple setup. The collected MS/MS spectra were then automatically searched by SEQUEST, and filtered and organized by DTASelect. Hundreds of silver-stained or CBB-stained Shewanella oneidensis, Geobacter sulfurreducens, and Geobacter metallireducens proteins separated by denaturing or nondenaturing 2-DE were digested and routinely analyzed using this fully automated muLC-MS/MS system. High peptide hits and sequence coverage were achieved for most CBB-stained gel spots. About 75% of the spots were found to contain multiple proteins. Although silver staining is not commonly thought to be optimal for MS analysis, protein identifications were successfully obtained from silver-stained 2-DE spots detected using methods with and without formaldehyde for protein fixation. PMID:16315175

Zhu, Wenhong; Venable, John; Giometti, Carol S; Khare, Tripti; Tollaksen, Sandra; Ahrendt, Angela J; Yates, John R

2005-12-01

165

Detection of glycoproteins in polyacrylamide gels using Pro-Q Emerald 300 dye, a fluorescent periodate Schiff-base stain.  

PubMed

Pro-Q Emerald 300 glycoprotein stain generates a bright-green fluorescent signal upon reacting with periodic acid-oxidized carbohydrate groups on proteins. With this dye, it is possible to detect proteins directly in the gel without the need to transfer them to a membrane. This dye is more sensitive than the standard periodic acid Schiff's base which uses acidic fuchsin dye. PMID:22585521

Mehta-D'souza, Padmaja

2012-01-01

166

Rapid fluorescent monitoring of total protein patterns on sodium dodecyl sulfate-polyacrylamide gels and western blots before immunodetection and sequencing.  

PubMed

The fluorogenic dye 2-methoxy-2,4-diphenyl-3(2H)-furanone (MDPF) has been used for the detection of total protein patterns on polyvinylidene difluoride (PVDF) membranes. Fluorescent staining of protein bands on membranes with this covalent dye is completed in 20 min. Wet membranes are translucent, allowing protein visualization by transillumination with ultraviolet light. The resulting images can be recorded using Polaroid film or a charge-coupled device camera. Electrophoretic bands containing 5-10 ng of protein can be detected on the MDPF-stained Western blot. When proteins are directly transferred to the membrane using a slot blotting device, as little as 0.5 ng of protein can be detected. Previous visualization of protein bands on sodium dodecyl sulfate-polyacrylamide gels with the noncovalent fluorescent dye Nile red (Alba et al., BioTechniques, 1996, 21, 625-626) does not interfere with further MDPF staining and fluorescent detection of these bands transferred to PVDF membranes. Thus, Nile red and MDPF staining can be performed sequentially, allowing the rapid monitoring of total protein patterns on both the electrophoretic gel and Western blot. Using the conditions described in this study, MDPF staining does not preclude further N-terminal microsequencing and immunodetection of specific bands with polyclonal antibodies. PMID:9820958

Alba, F J; Daban, J R

1998-10-01

167

Electrophoretic analysis of proteinases in sodium dodecyl sulfate-polyacrylamide gels containing copolymerized radiolabeled protein substrates: Application to proenkephalin processing enzymes  

SciTech Connect

A novel method is described for the zymographic analysis of proteinases in sodium dodecyl sulfate-polyacrylamide gels containing copolymerized radiolabeled protein substrates such as ({sup 35}S)methionine-labeled proenkephalin or {sup 125}I-labeled proinsulin. After electrophoresis the enzyme is reactivated and cleaves the radiolabeled in situ substrate into smaller peptides. These small peptides are able to diffuse out of the gel, leaving clear areas against a dark background when visualized by autoradiography. The technique can be used to detect as little as 200 fg of trypsin using only 50 ng (1.25 microCi) of ({sup 35}S)proenkephalin. Soluble- and membrane-bound adrenal trypsin-like enzyme were isolated from bovine adrenal chromaffin granules. Both proteinases cleaved ({sup 35}S)methionine-labeled proenkephalin but not {sup 125}I-labeled proinsulin. Moreover, both had a Mr of approximately 30,000. The potential of this technique for general use is discussed. An additional method using the synthetic fluorogenic substrate t-butoxycarbonyl Glu-Lys-Lys aminomethylcoumarin is also described.

Irvine, J.W.; Roberts, S.F.; Lindberg, I. (Louisiana State Univ. Medical Center, New Orleans (USA))

1990-10-01

168

On the efficiency of methylene blue versus persulfate catalysis of polyacrylamide gels, as investigated by capillary zone electrophoresis.  

PubMed

The efficiency of a novel method of photopolymerization, based on photoinitiating the reaction with methylene blue (MB), in presence of a redox couple (sodium toluenesulfinate and diphenyliodonium chloride), vs, the conventional persulfate--N,N,N',N'-tetramethylethylenediamine redox couple was investigated as a function of different effectors in solution. Oxygen dissolved in the gelling mixture strongly quenches persulfate catalysis, while leaving essentially unaltered the process initiated by photopolymerization. On the contrary, the presence of 8 M urea substantially accelerates a persulfate-driven reaction, boosting the conversion of monomers to near completion (> 98%) while leaving the photopolymerization process largely unaffected. Polyacrylamide polymerization has also been performed in a number of hydroorganic solvents (all in a 50:50 v/v ratio): dimethyl sulfoxide (DMSO), tetramethylurea, formamide and dimethylformamide. In all cases, the persulfate-catalyzed reaction was strongly quenched and even completely inhibited (in DMSO), whereas the photopolymerization process was essentially unaffected by any of these organic solvents. The reaction kinetics of the methylene blue-driven reaction could not be ameliorated when admixing an anionic dye (e.g., eosin Y) to the cationic MB, even when amply changing their molar ratios. Thus, it appears that photocatalysis with MB (and the redox couple sodium toluene-sulfinate and diphenyliodonium chloride) is a unique process, proceeding at optimum rate under the most adverse conditions, completely insensitive to any kind of positive and negative effectors and able to ensure at least 95% monomer conversion under the standard conditions of 1 h reaction time at room temperature.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8125068

Caglio, S; Righetti, P G

1993-10-01

169

Binding of Ubiquitin Conjugates to Proteasomes as Visualized with Native Gels  

PubMed Central

Summary The proteasome is an ATP-dependent molecular machine that degrades proteins through the concerted activity of dozens of subunits. It is the yin to the ribosome’s yang, and together these entities mold the protein landscape of the cell. Native gels are generally superior to conventional and affinity purifications for the analytical resolution proteasomal variants, and have thus become a staple of proteasome work. Here we describe the technique of using native gels to observe proteasomes in complex with ubiquitin conjugates. We discuss the consequences of ubiquitin conjugate length and concentration on the migration of these complexes, the use of this mobility shift to evaluate the relative affinity of mutant proteasomes for ubiquitin conjugates, and the effects of deubiquitinating enzymes and competing ubiquitin binding proteins on the interactions of ubiquitin conjugates with the proteasome.

Elsasser, Suzanne; Shi, Yuan; Finley, Daniel

2013-01-01

170

Identification of the commonest cystic fibrosis transmembrane regulator gene DeltaF508 mutation: evaluation of PCR--single-strand conformational polymorphism and polyacrylamide gel electrophoresis.  

PubMed

In the present study we investigated whether single-strand conformational polymorphism (SSCP) and polyacrylamide gel electrophoresis (PAGE) could be used for the identification of the CFTR DeltaF508 gene mutation, which is commonest in the Greek population. Using DNA from patients carrying this mutation, the appropriate 98 bp region of the CFTR gene was amplified by PCR and the reaction products were analysed by non-radioactive SSCP-electrophoresis using silver staining for band visualization and non-denaturating PAGE to confirm the results. SSCP electrophoretic analysis has been optimized for several parameters in order to achieve the best resolution. Single-strand DNA fragments gave a reproducible pattern of bands, characteristic for the particular mutation. Comparison of the obtain patterns with control samples allowed the detection of the DeltaF508 mutation in the patients studied by SSCP assay and these results were confirmed by the independent method of PAGE. Although SSCP and PAGE can be used for detection of this mutation, PAGE resulted in more distinct patterns than SSCP. It is, therefore, proposed that PAGE can be reliably used for the detection and identification of such a mutation in patients provided that suitable controls are available. The applicability of PAGE to identification of the mutation in carriers, particularly useful for population screening, is also discussed. PMID:16708396

Kakavas, K V; Noulas, A V; Kanakis, I; Bonanou, S; Karamanos, N K

2006-10-01

171

Definition of Mycobacterium tuberculosis culture filtrate proteins by two-dimensional polyacrylamide gel electrophoresis, N-terminal amino acid sequencing, and electrospray mass spectrometry.  

PubMed Central

A number of the culture filtrate proteins secreted by Mycobacterium tuberculosis are known to contribute to the immunology of tuberculosis and to possess enzymatic activities associated with pathogenicity. However, a complete analysis of the protein composition of this fraction has been lacking. By using two-dimensional polyacrylamide gel electrophoresis, detailed maps of the culture filtrate proteins of M. tuberculosis H37Rv were generated. In total, 205 protein spots were observed. The coupling of this electrophoretic technique with Western blot analysis allowed the identification and mapping of 32 proteins. Further molecular characterization of abundant proteins within this fraction was achieved by N-terminal amino acid sequencing and liquid chromatography-mass spectrometry. Eighteen proteins were subjected to N-group analysis; of these, only 10 could be sequenced by Edman degradation. Among the most interesting were a novel 52-kDa protein demonstrating significant homology to an alpha-hydroxysteroid dehydrogenase of Eubacterium sp. strain VPI 12708, a 25-kDa protein corresponding to open reading frame 28 of the M. tuberculosis cosmid MTCY1A11, and a 31-kDa protein exhibiting an amino acid sequence identical to that of antigen 85A and 85B. This latter product migrated with an isoelectric point between those of antigen 85A and 85C but did not react with the antibody specific for this complex, suggesting that there is a fourth member of the antigen 85 complex. Novel N-terminal amino acid sequences were obtained for three additional culture filtrate proteins; however, these did not yield significant homology to known protein sequences. A protein cluster of 85 to 88 kDa, recognized by the monoclonal antibodies IT-57 and IT-42 and known to react with sera from a large proportion of tuberculosis patients, was refractory to N-group analysis. Nevertheless, mass spectrometry of peptides obtained from one member of this complex identified it as the M. tuberculosis KatG catalase/peroxidase. Thus, the detailed mapping of M. tuberculosis proteins, combined with state-of-the-art analytical techniques such as mass spectrometry, provides a basis for further analysis and rapid identification of biologically relevant molecules.

Sonnenberg, M G; Belisle, J T

1997-01-01

172

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and monoclonal antibodies as tools for the subgrouping of Escherichia coli lipopolysaccharide O18 and O23 antigens.  

PubMed Central

The lipopolysaccharide (LPS) of Escherichia coli O18 isolated from a wide variety of sources was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Four different LPS types, designated O18A, O18A1, O18B, and O18B1, were identified. Most O18 strains possess O18A, O18A1, or O18B LPS types, and these types are clonally associated. A reference test strain with the classical O18ab designation possessed O18B LPS, while two reference O18ac strains possessed O18A and O18A1 LPS, respectively. A panel of 15 anti-O18A B-cell hybridomas was isolated. Enzyme-linked immunosorbent assays revealed that some of the monoclonal antibodies produced by these cells recognize different epitopes. Four of these antibodies suffice to distinguish the four O18 types. Numerous strains whose LPS had been typed by SDS-PAGE were tested by agglutination with seven monoclonal antibodies whose specificities had been determined by enzyme-linked immunosorbent assays. The results indicated a perfect correlation between the two methods. Rabbit antisera raised against O18A bacteria agglutinated boiled bacteria of each of the O18 LPS types efficiently. The antisera were adsorbed with bacteria possessing each of the LPS types. The adsorbed sera only distinguished between two groups: O18A and O18A1 versus O18B and O18B1, as shown by agglutination assays and Western blotting. E. coli O4 and O23 and Serratia marcescens O8 antigens, which are reputed to cross-react with O18, were also analyzed. One O4, one O8, and four O23 strains were tested. All made an LPS which was distinguishable from O18 LPS types by SDS-PAGE. Each O23 strain synthesized a different LPS, and three of them synthesized only few short chains. Some of the monoclonal antibodies reacted with O4, O8, and O23A LPSs. The results are interpreted as indicating that numerous E. coli O serogroups will prove to be chemically heterogeneous and that future analyses of subgroup heterogeneity should be guided by results from SDS-PAGE and rely preferentially on monoclonal antibodies as opposed to rabbit hyperimmune sera. Images

Pluschke, G; Moll, A; Kusecek, B; Achtman, M

1986-01-01

173

Blue Native electrophoresis to study mitochondrial and other protein complexes  

Microsoft Academic Search

The biogenesis and maintenance of mitochondria relies on a sizable number of proteins. Many of these proteins are organized into complexes, which are located in the mitochondrial inner membrane. Blue Native polyacrylamide gel electrophoresis (BN-PAGE) is a method for the isolation of intact protein complexes. Although it was initially used to study mitochondrial respiratory chain enzymes, it can also be

Leo G. J Nijtmans; Nadine S Henderson; Ian J Holt

2002-01-01

174

Distinction of different heat-treated bovine milks by native-PAGE fingerprinting of their whey proteins  

Microsoft Academic Search

Native-PAGE (polyacrylamide gel electrophoresis) was used for the simultaneous qualitative and quantitative analysis of whey proteins of raw, commercial and laboratory heat-treated bovine milks. Four whey protein bands, including ?-lactoglobulin variants (?-LG A and B), could be distinctively separated in the gel. The results showed that levels of the major whey proteins were reduced by less than 23% in the

Suju Lin; Jing Sun; Dongdong Cao; Jiankang Cao; Weibo Jiang

2010-01-01

175

The usefulness of the analytical electrofocusing in a thin-layer polyacrylamide gel (PAG) in the histochemistry of enzymes cleaving peptide bonds  

Microsoft Academic Search

The usefulness of the analytical electrofocusing in a thin-layer polyacrylamide (PAG) plate is shown on the basis of experiments with 10%–20% homogenates of various rat, rabbit and human organs as well as in lysates of isolated human lymphocytes and leucocytes in 2% Triton X100. 0.1–0.3 µl of 12000 g supernatants were applied on LKB Ampholine PAG plates pH range 3.5–9.5

Z. Lojda; J. Kulich

1981-01-01

176

[A method of isoelectric focusing in a borate-polyol system with pH gradient of 4.0 to 5.6 in a thin layer of polyacrylamide gel].  

PubMed

A procedure is described for thin-layer polyacrylamide gel isoelectric focusing involving borate-polyol system with gradient pH 4.0-5.6, where 0.5 M H3BO3-Tris was used as an electrode buffer. Riboflavin, TEMED, Tris-borate buffer and glycerol were used in preparation of gradient pH, which was stable and did not alter during the electrophoresis. Blood serum proteins, particularly blood serum albumin, from patients with diabetes were studied using the isoelectric focusing procedure. After isoelectrofocusing of blood serum albumin from patients with diabetes additional minor acid fractions of the protein were detected at pH 4.3-4.6. The procedure of electrophoresis in gradient pH 4.0-5.6 was highly effective and might be used in biochemical laboratories. PMID:3660734

Azhitski?, G Iu; Zagorul'ko, G V; Troitski?, G V

177

High-resolution Native-PAGE for membrane proteins capable of fluorescence detection and hydrodynamic state evaluation  

Microsoft Academic Search

An improved native polyacrylamide gel electrophoresis (PAGE) method capable of evaluating the hydrodynamic states of membrane proteins and allowing in-gel fluorescence detection was established. In this method, bis(alkyl) sulfosuccinate is used to provide negative charges for detergent-solubilized membrane proteins to facilitate proper electrophoretic migration without disturbing their native hydrodynamic states. The method achieved high-resolution electrophoretic separation, in good agreement with

Makoto Ihara; Noriko Matsuura; Atsuko Yamashita

2011-01-01

178

Diced electrophoresis gel assay for screening enzymes with specified activities.  

PubMed

We have established the diced electrophoresis gel (DEG) assay as a proteome-wide screening tool to identify enzymes with activities of interest using turnover-based fluorescent substrates. The method utilizes the combination of native polyacrylamide gel electrophoresis (PAGE) with a multiwell-plate-based fluorometric assay to find protein spots with the specified activity. By developing fluorescent substrates that mimic the structure of neutrophil chemoattractants, we could identify enzymes involved in metabolic inactivation of the chemoattractants. PMID:23581642

Komatsu, Toru; Hanaoka, Kenjiro; Adibekian, Alexander; Yoshioka, Kentaro; Terai, Takuya; Ueno, Tasuku; Kawaguchi, Mitsuyasu; Cravatt, Benjamin F; Nagano, Tetsuo

2013-04-16

179

Proteome analysis of human stomach tissue: separation of soluble proteins by two-dimensional polyacrylamide gel electrophoresis and identification by mass spectrometry.  

PubMed

Two-dimensional gel electrophoresis (2-DE) maps for human stomach tissue proteins have been prepared by displaying the protein components of the tissue by 2-DE and identifying them using mass spectrometry. This will enable us to present an overview of the proteins expressed in human stomach tissues and lays the basis for subsequent comparative proteome analysis studies with gastric diseases such as gastric cancer. In this study, 2-DE maps of soluble fraction proteins were prepared on two gel images with partially overlapping pH ranges of 4-7 and 6-9. On the gels covering pH 4-7 and pH 6-9, about 900 and 600 protein spots were detected by silver staining, respectively. For protein identification, proteins spots on micropreparative gels stained with colloidal Coomassie Brilliant Blue G-250 were excised, digested in-gel with trypsin, and analyzed by peptide mass fingerprinting with delayed extraction-matrix assisted laser desorption/ionization-mass spectrometry (DE-MALDI-MS). In all, 243 protein spots (168 spots in acidic map and 75 spots in basic map) corresponding to 136 different proteins were identified. Besides these principal maps, overview maps (displayed on pH 3-10 gels) for total homogenate and soluble fraction, are also presented with some identifications mapped on them. Based on the 2-DE maps presented in this study, a 2-DE database for human stomach tissue proteome has been constructed and is available at http://proteome.gsnu.ac.kr/DB/2DPAGE/Stomach/. The 2-DE maps and the database resulting from this study will serve important resources for subsequent proteomic studies for analyzing the normal protein variability in healthy tissues and specific protein variations in diseased tissues. PMID:12210210

Ha, Geun Hyoung; Lee, Seung Uook; Kang, Deok Gyeong; Ha, Na-Young; Kim, Soon Hee; Kim, Jina; Bae, Jong Min; Kim, Jae Won; Lee, Chang-Won

2002-08-01

180

Characterization of the aerosol produced by infrared femtosecond laser ablation of polyacrylamide gels for the sensitive inductively coupled plasma mass spectrometry detection of selenoproteins  

Microsoft Academic Search

A 2D high repetition rate femtosecond laser ablation strategy (2-mm wide lane) previously developed for the detection of selenoproteins in gel electrophoresis by inductively coupled plasma mass spectrometry was found to increase signal sensitivity by a factor of 40 compared to conventional nanosecond ablation (0.12-mm wide lane) [G. Ballihaut, F. Claverie, C. Pécheyran, S. Mounicou, R. Grimaud and R. Lobinski,

Fanny Claverie; Christophe Pécheyran; Sandra Mounicou; Guillaume Ballihaut; Beatriz Fernandez; Joël Alexis; Ryszard Lobinski; Olivier F. X. Donard

2009-01-01

181

Relative Quantitative Comparisons of the Extracellular Protein Profiles of Staphylococcus aureus UAMS-1 and Its sarA, agr, and sarA agr Regulatory Mutants Using One-Dimensional Polyacrylamide Gel Electrophoresis and Nanocapillary Liquid Chromatography Coupled with Tandem Mass Spectrometry  

Microsoft Academic Search

One-dimensional polyacrylamide gel electrophoresis followed by nanocapillary liquid chromatography cou- pled with mass spectrometry was used to analyze proteins isolated from Staphylococcus aureus UAMS-1 after 3, 6, 12, and 24 h of in vitro growth. Protein abundance was determined using a quantitative value termed normalized peptide number, and overall, proteins known to be associated with the cell wall were more

Richard C. Jones; Joanna Deck; Ricky D. Edmondson; Mark E. Hart

2008-01-01

182

Iron-induced conformational change in human lactoferrin: demonstration by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and analysis of effects of iron binding to the N and C lobes of the molecule.  

PubMed

Analysis of Fe-saturated- and apo-lactoferrin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) without heating the samples prior to application revealed a substantial difference in mobility. The mobility shift was fully reversible on repetitive removal and readdition of Fe. Binding of a single Fe to the N-lobe binding site was sufficient to cause the gel shift; binding of a second Fe to the C-lobe site did not further alter mobility. Removal of Fe from the N lobe of Fe2 lactoferrin did not restore mobility to the position of apolactoferrin. No change in mobility with Fe binding was detected in N and C lobes isolated from intact lactoferrin by controlled trypsin digestion. The data indicate that a conformational change induced by Fe binding to a single site on lactoferrin is detectable by SDS-PAGE and that this change requires an intact molecule, possibly due to the need for interactions between the two homologous lobes of the molecule. PMID:8026441

Ying, L; He, J; Furmanski, P

1994-02-01

183

India ink staining after sodium dodecyl sulfate polyacrylamide gel electrophoresis and in conjunction with Western blots for peptide mapping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.  

PubMed

We present an approach that allows matrix-assisted laser desorption/ionization time-of-flight mass spectrometric (MALDI-TOFMS) peptide mapping of proteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electroblotted onto nitrocellulose (NC). After blocking the nitrocellulose membrane with polyvinylpyrrolidone-40 the immobilized proteins are visualized using India Ink staining which allows the detection of low nanogram amounts of protein. The utilization of a low concentration of Tween 20 (0.05%) in the India Ink staining solution does not negatively impair the quality of the mass spectra. Due to the virtual nondestructive nature of the stain proteolytic peptides could be recovered from the NC membrane. Taking into account minor precautions during the sample manipulation and concentration and by loading the sample onto a pre-crystallized matrix layer, high quality mass spectral data were obtained on <100 femtomoles of protein loaded onto the gel. Finally, the use of India Ink in conjunction with Western blot analysis is also demonstrated. A rat plasma protein, characterized by Western blot as a covalently modified protein-drug compound, was subjected to peptide mapping and post source decay (PSD) sequencing of peptides. The zomepirac-modified protein was identified as the alpha-subunit of fibrinogen. PMID:11754245

Klarskov, Klaus; Naylor, Stephen

2002-01-01

184

Oligo(dT) is not a correct native PAGE marker for single-stranded DNA  

Microsoft Academic Search

Polyacrylamide gel electrophoresis is a widely used method to study short DNA fragments in solution. It is, however, a relative method requiring length markers to assess mobility, shape, flexibility, and molecularity of the DNA structures of interest. In recent literature we have encountered the use of oligo(dT) fragments as the native PAGE length markers. We show here that this practice

Iva Kejnovská; Jaroslav Kypr; Michaela Vorlí?ková

2007-01-01

185

Blue-native PAGE in plants: a tool in analysis of protein-protein interactions  

PubMed Central

Intact protein complexes can be separated by apparent molecular mass using a standard polyacrylamide gel electrophoresis system combining mild detergents and the dye Coomassie Blue. Referring to the blue coloured gel and the gentle method of solubilization yielding native and enzymatically active protein complexes, this technique has been named Blue-Native Polyacrylamide Gel-Electrophoresis (BN-PAGE). BN-PAGE has become the method of choice for the investigation of the respiratory protein complexes of the electron transfer chains of a range of organisms, including bacteria, yeasts, animals and plants. It allows the separation in two dimensions of extremely hydrophobic protein sets for analysis and also provides information on their native interactions. In this review we discuss the capabilities of BN-PAGE in proteomics and the wider investigation of protein:protein interactions with a focus on its use and potential in plant science.

Eubel, Holger; Braun, Hans-Peter; Millar, A Harvey

2005-01-01

186

Preparation of aqueous polyacrylamide solutions for enhanced oil recovery  

SciTech Connect

A process is described for producing a dilute polyacrylamide solution comprising: (a) providing a polyacrylamide gel of from about 6 to about 15% polymer solids and having a solution viscosity of from about 3 to 10 cps, as measured on a 0.1% polymer solution in 1N NaCl in a Brookfield viscometer equipped with UL adaptor at 60 rpm and at 25/sup 0/C; (b) conveying the polyacrylamide gel and a minor amount of aqueous media through at least one static cutting device to provide a substantially non-degraded, concentrated aqueous slurry of finely divided gel particles; (c) dissolving and homogenizing the concentrated gel slurry in the aqueous media to provide a homogeneous solution concentrate; and (d) thereafter, diluting the solution concentrate with aqueous media until a dilute polyacrylamide solution of desired polymer solids content is obtained.

Whiteford, J.M.; Pellon, J.J.; Colman, W.P.

1986-08-12

187

Francisella tularensis membrane complexome by blue native\\/SDS-PAGE  

Microsoft Academic Search

The study of membrane proteins and membrane protein complexes (MPC) provides crucial information in the field of bacterial physiology and pathogenesis research. The method of blue native polyacrylamide gel electrophoresis and its combination with SDS-PAGE (BN\\/SDS-PAGE) were here employed to study the membrane complexome of an intracellular bacterium Francisella tularensis, the causative agent of a severe disease tularemia. In the

Jiri Dresler; Jana Klimentova; Jiri Stulik

188

Preparation of aqueous polyacrylamide solutions for enhanced oil recovery  

Microsoft Academic Search

A process is described for producing a dilute polyacrylamide solution comprising: (a) providing a polyacrylamide gel of from about 6 to about 15% polymer solids and having a solution viscosity of from about 3 to 10 cps, as measured on a 0.1% polymer solution in 1N NaCl in a Brookfield viscometer equipped with UL adaptor at 60 rpm and at

J. M. Whiteford; J. J. Pellon; W. P. Colman

1986-01-01

189

System for Gel Electrophoretic Immunoassay.  

National Technical Information Service (NTIS)

A micro-analytical platform for performing electrophoresis-based immunoassays was developed by integrating photopolymerized cross-linked polyacrylamide gels within a microfluidic device. The microfluidic immunoassays are performed by gel electrophoretic s...

A. E. Herr A. K. Singh D. J. Throckmorton

2005-01-01

190

Biotinylation of protein complexes may lead to aggregation as well as to loss of subunits as revealed by Blue Native PAGE  

Microsoft Academic Search

Blue Native polyacrylamide gel electrophoresis (BN-PAGE) is a high-resolution method for studying native protein complexes. Here, the migration behaviour of the B cell antigen receptor (BCR) in BN-PAGE with and without prior biotinylation of the cell surface, from which the complexes were purified, are compared. Non-biotinylated complexes appear as a single band, whereas biotinylated complexes display several bands, indicating that

Wolfgang W. A Schamel

2001-01-01

191

Microchannel gel electrophoretic separation systems and methods for preparing and using  

DOEpatents

A micro-analytical platform for performing electrophoresis-based immunoassays was developed by integrating photopolymerized cross-linked polyacrylamide gels within a microfluidic device. The microfluidic immunoassays are performed by gel electrophoretic separation and quantifying analyte concentration based upon conventional polyacrylamide gel electrophoresis (PAGE). To retain biological activity of proteins and maintain intact immune complexes, native PAGE conditions were employed. Both direct (non-competitive) and competitive immunoassay formats are demonstrated in microchips for detecting toxins and biomarkers (cytokines, c-reactive protein) in bodily fluids (serum, saliva, oral fluids). Further, a description of gradient gels fabrication is included, in an effort to describe methods we have developed for further optimization of on-chip PAGE immunoassays. The described chip-based PAGE immunoassay method enables immunoassays that are fast (minutes) and require very small amounts of sample (less than a few microliters). Use of microfabricated chips as a platform enables integration, parallel assays, automation and development of portable devices.

Herr, Amy; Singh, Anup K; Throckmorton, Daniel J

2013-09-03

192

Gel drying methods.  

PubMed

For some instances, protein gels need to be dried after SDS-PAGE, for example, if autoradiography should be performed from radioactive-labeled proteins after their separation on SDS-polyacrylamide gels. Another reason may be to simply store the gel in the laboratory book. Aside from expensive commercial solutions, especially for storage of the dried gel in the lab book, the simple and cheap drying protocol here presented may be sufficient. PMID:22585507

Stamova, Slava; Michalk, Irene; Bartsch, Holger; Bachmann, Michael

2012-01-01

193

Identification of PSME3 as a Novel Serum Tumor Marker for Colorectal Cancer by Combining Two-dimensional Polyacrylamide Gel Electrophoresis with a Strictly Mass Spectrometry-based Approach for Data Analysis  

Microsoft Academic Search

The purpose of this study was to identify and validate novel serological protein biomarkers of human colorectal cancer (CRC). Proteins from matched CRC and adjacent normal tissue samples were resolved by two-dimensional gel electrophoresis. From each gel all spots were excised, and enveloped proteins were identified by MS. By com- parison of the resulting protein profiles, dysregulated pro- teins can

Markus Roessler; Wolfgang Rollinger; Liliana Mantovani-Endl; Marie-Luise Hagmann; Stefan Palme; Peter Berndt; Alfred M. Engel; Michael Pfeffer; Johann Karl; Heinz Bodenmuller; Josef Ruschoff; Thomas Henkel; Gerhard Rohr; Siegbert Rossol; Wolfgang Rosch; Hanno Langen; Werner Zolg; Michael Tacke

2006-01-01

194

Method and Apparatus for Gel Electrophoretic Immunoassay.  

National Technical Information Service (NTIS)

A micro-analytical platform for performing electrophoresis-based immunoassays was developed by integrating photopolymerized cross-linked polyacrylamide gels within a microfluidic device. The microfluidic immunoassays are performed by gel electrophoretic s...

A. E. Herr A. K. Singh D. J. Throckmorton

2005-01-01

195

In-gel phosphatase assay using non-denaturing two-dimensional electrophoresis.  

PubMed

We developed a method for detecting phosphatase activities in crude tissue extracts after separation of proteins by a novel non-denaturing two-dimensional electrophoresis. In the first dimension, protein samples were separated by a MicroRotofor, a liquid-phase isoelectric focusing, in the presence or absence of urea. In the second dimension, fractionated proteins by the MicroRotofor were resolved by a native polyacrylamide gel electrophoresis in the presence of 20 mM 2-mercaptoethanol. After electrophoresis, the polyacrylamide gel was directly immersed in a reaction mixture containing 4-methylumbelliferyl phosphate (MUP), a fluorogenic substrate, and phosphatase activities were detected as fluorescent bands. In this assay, a variety of phosphatase activities were clearly detected in gel when the tissue extracts were separated by the MicroRotofor in the presence of 1.5 M urea. Furthermore, after detecting phosphatase activities in polyacrylamide gel at neutral pH, its activities at acidic pH could be detected by immersing the gel in sodium citrate buffer (pH 3.0). Therefore, this method is a quite useful technique to analyze various phosphatases by sequential reactions with MUP under different conditions after sample separation by the two-dimensional electrophoresis. PMID:22992841

Baba, Hiromi; Masuda, Yukihiro; Sueyoshi, Noriyuki; Kameshita, Isamu

2012-09-19

196

Purification of Multisubunit Membrane Protein Complexes: Isolation of Chloroplast F oF 1ATP Synthase, CF o and CF 1 by Blue Native Electrophoresis  

Microsoft Academic Search

The proton-ATP synthase of thylakoid membranes from chloroplasts (CFoF1) is composed of two parts with different structural and functional properties: the membrane-integral, proton-conducting complex CFo and the hydrophilic part, CF1 which catalyze the formation of adenosine-5?-triphosphate (ATP). To date it is difficult to isolate functional CFoF1 from thylakoids in high purity and yield. Blue native polyacrylamide gel electrophoresis (BN-PAGE) was

Dirk Neff; Norbert A. Dencher

1999-01-01

197

Analysis of white spot syndrome virus envelope protein complexome by two-dimensional blue native\\/SDS PAGE combined with mass spectrometry  

Microsoft Academic Search

White spot syndrome virus (WSSV) is a large enveloped virus, but the organization of its envelope proteins remains largely\\u000a unknown. In the present study, we used blue native polyacrylamide gel electrophoresis (BN-PAGE) and SDS-PAGE in combination\\u000a with mass spectrometry to analyze the envelope protein complexome of WSSV. Our results show that the viral envelope consists\\u000a of multi-protein complexes (MPCs). Within

Zichong Li; Limei Xu; Fang Li; Qing Zhou; Feng Yang

2011-01-01

198

Proteomics study on the hepatoprotective effects of traditional Chinese medicine formulae Yin-Chen-Hao-Tang by a combination of two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry.  

PubMed

Proteomics can bring breakthroughs in the study of traditional Chinese medicine (TCM). Yin-Chen-Hao-Tang (YCHT), a famous TCM formulae, has been used to alleviate various types of liver injury. However, the underlying mechanisms and drug targets of YCHT associated with the hepatic injury are largely unknown. To identify the possible target proteins of YCHT, two-dimensional gel electrophoresis (2-DE)-based proteomics was performed and proteins altered after YCHT treatment were identified by MALDI-TOF/TOF-MS. Interestingly, 15 modulated proteins were identified, out of which 7 were found to be significantly altered by YCHT. YCHT treatment caused a statistically significant down-regulation of zinc finger protein 407, haptoglobin, macroglobulin, alpha-1-antitrypsin; significant up-regulation of transthyretin, vitamin D-binding protein, and prothrombin, appear to be involved in metabolism, energy generation, chaperone, antioxidation, signal transduction, protein folding and apoptosis. Finally, interaction network from 7 differentially expressed protein to the signal-related proteins was established using bioinformatic analysis. Of note, these signal-related proteins could be included in a network together with 7 proteins through direct interaction or only one intermediate partner. Functional pathway analysis suggested that these proteins were closely related in the protein-protein interaction network and the modulation of multiple vital physiological pathways. Thus, our data will help to understand the molecular mechanisms of hepatoprotective effects of YCHT. PMID:23262417

Sun, Hui; Zhang, Aihua; Yan, Guangli; Han, Ying; Sun, Wenjun; Ye, Yuan; Wang, Xijun

2012-11-23

199

Combining blue native polyacrylamide gel electrophoresis with liquid chromatography tandem mass spectrometry as an effective strategy for analyzing potential membrane protein complexes of Mycobacterium bovis bacillus Calmette-Guérin  

Microsoft Academic Search

BACKGROUND: Tuberculosis is an infectious bacterial disease in humans caused primarily by Mycobacterium tuberculosis, and infects one-third of the world's total population. Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine has been widely used to prevent tuberculosis worldwide since 1921. Membrane proteins play important roles in various cellular processes, and the protein-protein interactions involved in these processes may provide further information about

Jianhua Zheng; Candong Wei; Lina Zhao; Liguo Liu; Wenchuan Leng; Weijun Li; Qi Jin

2011-01-01

200

Nanotube-grafted polyacrylamide hydrogels for electrophoretic protein separation.  

PubMed

Multiwalled carbon nanotube-modified polyacrylamide gels have been employed for the electrophoretic separation of proteins. Two approaches are compared in this investigation, one using nanotubes only as fillers inside the gel matrix and the other using nanotubes as catalyst for polymerization of acrylamide. In both the cases, polymerization of acryl-amide/bisacrylamide has been carried out in situ in the presence of nanotubes dispersed in the gel buffer containing monomer and cross-linker. In the former case, initiator and catalyst have been added after ultrasonication of nanotubes in the gel buffer mixture where the nanotubes play the role of filler. On the other hand, the second approach precludes use of catalyst and involves addition of initiator alone during ultrasonication of nanotubes in the gel buffer containing monomer and cross-linker, which leads to the formation of nanotube-grafted gel after 25 min. When nanotubes are used as a catalyst instead of N,N,N',N'-tetramethylethylenediamine, pore size distribution of the gel matrix and linearity of molecular weight calibration plots are found to be improved. In addition, other issues associated with the use of an external catalyst like handling the moisture-sensitive and corrosive reagent and associated irreproducibility are addressed in this approach. PMID:22589105

Gunavadhi, Murugappan; Maria, Lourdusamy Arul Antony; Chamundeswari, Vidya N; Parthasarathy, Meera

2012-04-01

201

Spring-loaded polymeric gel actuators  

DOEpatents

Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications.

Shahinpoor, Mohsen (Albuquerque, NM)

1995-01-01

202

Spring-loaded polymeric gel actuators  

DOEpatents

Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications. 5 figs.

Shahinpoor, M.

1995-02-14

203

Molecular Recognition in Gels, Monolayers, and Solids.  

National Technical Information Service (NTIS)

This paper describes work in four area:affinity electrophoresis of carbonic anhydrase in cross-linked polyacrylamide-derived gels containing immobilized derivatives of aryl sulfonamides; inhibition of the hemagglutination of erythrocytes induced by influe...

K. L. Prime Y. H. Chu W. Schmid C. T. Seto J. K. Chen

1991-01-01

204

Magnetic and spectroscopic properties of Polyacrylamide-CoFe2O4 magnetic hydrogel  

NASA Astrophysics Data System (ADS)

This study investigates synthesis and characterization of polyacrylamide (PAAm) hydrogels containing ferromagnetic CoFe2O4 nanoparticles. Structural, electrical, and magnetic characterization of the gels have been performed with X-ray powder diffractometry, Scanning electron microscopy, DC conductivity, magnetization and fluorescence spectroscopy techniques. Fluorescence and electrical measurements show that nanoparticles have trapped in the gel so they cannot move through the gel even if the gel is swollen and the voltage is applied. Pyranine molecules diffuse easily through the gel due to the presence of ferromagnetic nanoparticles. As number of diffused pyranine molecules increases current densities of the magnetic hydrogel increase. Magnetization measurements reveal that CoFe2O4 nanoparticles do not diffuse out of the gel during swelling. As a result, total magnetization of the gel do not change as volume of the gel increases.

Alvero?lu, E.; Sözeri, H.; Kurtan, U.; ?enel, M.; Baykal, A.

2013-03-01

205

Templated Native Silk Smectic Gels.  

National Technical Information Service (NTIS)

One aspect of the present invention relates to a method of preparing a fibrous protein smectic hydrogel by way of a solvent templating process, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that ...

H. H. Jin J. H. Park R. Valluzzi

2003-01-01

206

Separation and isolation of fusion protein using a new native preparative PAGE device.  

PubMed

A human serum albumin and Thymosin ?1 (HSA-T?1) fusion protein was designed and over-expressed in Pichia pastoris. To purify the fusion protein, a new native preparative electrophoresis system that involved a modified device with a sample receiving chamber, and an assay method with Coomassie Blue G-250 tracing the collection of the protein of interest. In this device, two gels were run in parallel: native vertical collecting polyacrylamide gel electrophoresis (PAGE) and native vertical tracing PAGE. Samples mixed with or without Coomassie Blue G-250 loading buffer were separately loaded to the two aforementioned gels, and the fractions were collected until the tracing protein band combined with dye reached 1 cm from the sample-receiving chamber at the bottom of the gel. Approximately nine fractions were collected at regular intervals of 15 min. HSA-T?1 fusion protein with 95% relative homogeneity was harvested and manifested similar immunological activities as synthetic T?1 after a single-step purification of this preparative PAGE. As a result, this system offers a new, rapid and simple method for the purification of the protein of interest. PMID:22718746

Jian-Hua, Zhang Xin-Guo Chen; Lu-Yin, Yan; Li, Tang; Min, Wang; Dai-Shuang, Cheng

2012-06-19

207

Blue native PAGE  

Microsoft Academic Search

Blue native PAGE (BN-PAGE) can be used for one-step isolation of protein complexes from biological membranes and total cell and tissue homogenates. It can also be used to determine native protein masses and oligomeric states and to identify physiological protein–protein interactions. Native complexes are recovered from gels by electroelution or diffusion and are used for 2D crystallization and electron microscopy

Ilka Wittig; Hans-Peter Braun; Hermann Schägger

2006-01-01

208

Nondenaturing electrophoresis of lipoproteins in agarose and polyacrylamide gradient gels.  

National Technical Information Service (NTIS)

The plasma lipoproteins frequently are classified according to density and/or electrophoretic mobility. The lipoprotein classes differ characteristically also in particle size and apolipoprotein composition. Each class is heterogeneous in size and composi...

V. G. Shore

1989-01-01

209

Directed evolution of formate dehydrogenase from Candida boidinii for improved stability during entrapment in polyacrylamide.  

PubMed

In two cycles of an error-prone PCR process, variants of formate dehydrogenase from Candida boidinii were created which revealed an up to 4.4-fold (440%) higher residual activity after entrapment in polyacrylamide gels than the wild-type enzyme. These were identified in an assay using single precursor molecules of polyacrylamide instead of the complete gel for selection. The stabilization resulted from an exchange of distinct lysine, glutamic acid, and cysteine residues remote from the active site, which did not affect the kinetics of the catalyzed reaction. Thermal stability increased at the exchange of lysine and glutamic acid, but decreased due the exchange of cysteine. Overall, the variants reveal very suitable properties for application in a technical synthetic process, enabling use of entrapment in polyacrylamide as an economic and versatile immobilization method. PMID:16879615

Ansorge-Schumacher, Marion B; Slusarczyk, Heike; Schümers, Julia; Hirtz, Dennis

2006-07-19

210

Effect of temperature on gelation time for polyacrylamide-chromium (III) systems  

Microsoft Academic Search

Gelled polymers are being applied to modify the movement of injected fluids in the vicinity of injection and production wells in secondary and enhanced oil recovery projects. The purposes of this work were to obtain experimental data on the effect of temperature on gelation time for typical polyacrylamide-Cr (III) gel systems over the range of temperatures commonly encountered in reservoirs

D. S. Jordan; D. W. Green; R. E. Terry; G. P. Willhite

1981-01-01

211

The Effect of Temperature on Gelation Time for Polyacrylamide\\/Chromium (III) Systems  

Microsoft Academic Search

Gelled polymers are being applied to modify the movement of injected fluids in the vicinity of injection and production wells in secondary and enhanced oil-recovery projects. One approach to gelation is to form a bulk gel in situ by injecting a slug of a polyacrylamide polymer solution containing chromium(VI) followed by a polymer slug containing a reducing agent such as

Deborah Jordan; Don Green; Ronald Terry; G. P. Willhite

1982-01-01

212

Francisella tularensis membrane complexome by blue native/SDS-PAGE.  

PubMed

The study of membrane proteins and membrane protein complexes (MPC) provides crucial information in the field of bacterial physiology and pathogenesis research. The method of blue native polyacrylamide gel electrophoresis and its combination with SDS-PAGE (BN/SDS-PAGE) were here employed to study the membrane complexome of an intracellular bacterium Francisella tularensis, the causative agent of a severe disease tularemia. In the presented study we describe the subunit composition and stoichiometry of several MPC involved in various cell functions (oxidative phosphorylation, membrane transport, cell division, membrane or periplasmic proteins folding, iron storage, phospholipid and cell envelope biosynthesis). Moreover, some undocumented or hypothetical MPC with possible connection to virulence factors were also proposed and some newly detected subunits were assigned to known complexes. The BN/SDS-PAGE combined with mass spectrometry appeared to be a strong tool in the investigation of membrane proteins and complexes and thus successfully complements the traditional electrophoresis approaches. PMID:21601022

Dresler, Jiri; Klimentova, Jana; Stulik, Jiri

2011-05-11

213

Electrically controlled polymeric gel actuators  

DOEpatents

Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

Adolf, Douglas B. (Albuquerque, NM); Shahinpoor, Mohsen (Albuquerque, NM); Segalman, Daniel J. (Albuquerque, NM); Witkowski, Walter R. (Albuquerque, NM)

1993-01-01

214

Electrically controlled polymeric gel actuators  

DOEpatents

Electrically controlled polymeric gel actuators or synthetic muscles are described capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots. 11 figures.

Adolf, D.B.; Shahinpoor, M.; Segalman, D.J.; Witkowski, W.R.

1993-10-05

215

Characterization of native and histidine-tagged deoxyxylulose 5-phosphate reductoisomerase from the cyanobacterium Synechocystis sp. PCC6803.  

PubMed

The dxr gene encoding the 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) from the cyanobacterium Synechocystis sp. PCC6803 was expressed in Escherichia coli to produce both the native and N-terminal histidine-tagged forms of DXR. The enzymes were purified from the cell extracts using either anion exchange chromatography or metal affinity chromatography and gel filtration. The purified recombinant native and histidine-tagged enzymes each displayed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels, corresponding to the calculated subunit molecular weights of 42,500 and 46,700, respectively. By native PAGE, both enzymes were dimers under reducing conditions. The kinetic properties for the enzymes were characterized and only minor variations were observed, demonstrating that the N-terminal histidine tag does not greatly affect the activity of the enzyme. Both enzymes had similar properties to previously characterized reductoisomerases from other sources. The K(m)'s for the metal ions Mn(2+), Mg(2+), and Co(2+) were determined for native DXR for the first time, with the K(m) for Mg(2+) being approximately 200-fold higher than the K(m)'s for Mn(2+) and Co(2+). PMID:14580998

Yin, Xihou; Proteau, Philip J

2003-11-01

216

Proteomic Screen for Multiprotein Complexes in Synaptic Plasma Membrane from Rat Hippocampus by Blue Native Gel Electrophoresis and Tandem Mass Spectrometry  

Microsoft Academic Search

Neuronal synapses are specialized sites for information exchange between neurons. Many diseases, such as addiction and mood disorders, likely result from altered expression of synaptic proteins, or altered formation of synaptic complexes involved in neurotransmission or neuroplasticity. A detailed description of native multiprotein complexes in synaptic plasma membranes (PM) is therefore essential for understanding biological mechanisms and disease processes. For

Xuanwen Li; Chunliang Xie; Qihui Jin; Mingjun Liu; Quanyuan He; Rui Cao; Yong Lin; Jianglin Li; Yan Li; Ping Chen; Songping Liang

2009-01-01

217

Surface Creasing Instability of Soft Polyacrylamide Cell Culture Substrates  

PubMed Central

Efforts to understand and engineer cell behavior in mechanically soft environments frequently employ two-dimensional cell culture substrates consisting of thin hydrogel layers with low elastic modulus supported on rigid substrates to facilitate culturing, imaging, and analysis. Here we characterize how an elastic creasing instability of the gel surface may occur for the most widely used soft cell culture substrate, polyacrylamide hydrogels, and show that stem cells respond to and change their behavior due to these surface features. The regions of stability and corresponding achievable ranges of modulus are elucidated in terms of the monomer and cross-linker concentrations, providing guidance for the synthesis of both smooth and creased soft cell substrates for basic and applied cell engineering efforts.

Saha, Krishanu; Kim, Jungwook; Irwin, Elizabeth; Yoon, Jinhwan; Momin, Farhana; Trujillo, Veronica; Schaffer, David V.; Healy, Kevin E.; Hayward, Ryan C.

2010-01-01

218

Application of rod-shaped cellulose nanocrystals in polyacrylamide hydrogels.  

PubMed

Rod-shaped cellulose nanocrystals (CNCs) were manufactured and used to reinforce polyacrylamide (PAM) hydrogels through in situ free-radical polymerization. The gelation process of the nanocomposite hydrogels was monitored on a rheometer using oscillatory shear. The chemical structure, morphology, swelling property, and compression strength of the formed gels were investigated. A possible mechanism for forming hydrogels was proposed. The results showed that CNCs accelerated the formation of hydrogels and increased the effective crosslink density of hydrogels. Thus CNCs were not only a reinforcing agent for hydrogel, but also acted as a multifunctional cross-linker for gelation. The shear storage modulus, compression strength and elastic modulus of the nanocomposite hydrogels were significantly improved because of good dispersion of CNCs in PAM as well as enhanced interfacial interaction between these two components. Among the CNC contents used, a loading of 6.7 w/w% led to the maximum mechanical properties for nanocomposite hydrogels. PMID:20932533

Zhou, Chengjun; Wu, Qinglin; Yue, Yiying; Zhang, Quanguo

2010-09-18

219

Hybrid Gel Composed of Native Heart Matrix and Collagen Induces Cardiac Differentiation of Human Embryonic Stem Cells without Supplemental Growth Factors  

Microsoft Academic Search

Our goal was to assess the ability of native heart extracellular matrix (ECM) to direct cardiac differentiation of human embryonic\\u000a stem cells (hESCs) in vitro. In order to probe the effects of cardiac matrix on hESC differentiation, a series of hydrogels\\u000a was prepared from decellularized ECM from porcine hearts by mixing ECM and collagen type I at varying ratios. Maturation

Yi Duan; Zen Liu; John O’Neill; Leo Q. Wan; Donald O. Freytes; Gordana Vunjak-Novakovic

220

Adverse reactions following injection with a permanent facial filler polyacrylamide hydrogel (Aquamid): causes and treatment  

Microsoft Academic Search

Background  Polyacrylamide hydrogel (Aquamid), an atoxic non-immunogenic gel of the non-resorbable type, has gained widespread popularity as an injectable filler for facial augmentation. However, adverse events (AEs) have occurred, the nature of which seems obscure because of negative findings on culture and a pattern of foreign-body response on microscopy.Design  This is a prospective study of case reports provided by physicians injecting Aquamid

Lise Christensen; Vibeke Breiting; Jens Vuust; Estrid Hogdall

2006-01-01

221

Pouring and running a protein gel by reusing commercial cassettes.  

PubMed

The evaluation of proteins using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis is a common technique used by biochemistry and molecular biology researchers. For laboratories that perform daily analyses of proteins, the cost of commercially available polyacrylamide gels (~$10/gel) can be considerable over time. To mitigate this cost, some researchers prepare their own polyacrylamide gels. Traditional methods of pouring these gels typically utilize specialized equipment and glass gel plates that can be expensive and preclude pouring many gels and storing them for future use. Furthermore, handling of glass plates during cleaning or gel pouring can result in accidental breakage creating a safety hazard, which may preclude their use in undergraduate laboratory classes. Our protocol demonstrates how to pour multiple protein gels simultaneously by recycling Invitrogen Nupage Novex minigel cassettes, and inexpensive materials purchased at a home improvement store. This economical and streamlined method includes a way to store the gels at 4°C for a few weeks. By re-using the plastic gel cassettes from commercially available gels, labs that run frequent protein gels can save significant costs and help the environment. In addition, plastic gel cassettes are extremely resistant to breakage, which makes them ideal for undergraduate laboratory classrooms. PMID:22349047

Hwang, Alexander C; Grey, Paris H; Cuddy, Katrina; Oppenheimer, David G

2012-02-12

222

Taste sensing with polyacrylamide grafted cellulose  

Microsoft Academic Search

The research work covers polymer membrane preparation, morphology study, and structural characterization of the membrane and study of the taste sensing characteristics of membrane for five different taste substances. FTIR spectroscopic analysis, UV spectroscopic analysis and SEM were carried for the structure and morphology of polyacrylamide (PAM) grafted cellulose membrane. Sensor characteristics (temporal stability, response stability, response to different taste

Sarmishtha Majumdar; Basudam Adhikari

2006-01-01

223

Polyacrylamide effects on infiltration in irrigated agriculture  

Microsoft Academic Search

Using polyacrylamide (PAM) following the NRCS conservation practice standard increases infiltration in furrow irrigation. PAM at 10 g in-' (10 ppm) during water advance nearly precludes detachment and transport of soil in furrows. If any sediment is entrained in the flow, it is readily flocculated in the presence of PAM and settles to the furrow-bottom in loose per- vious structures.

R. E. Sojka; R. D. Lentz; C. W. Ross; T. J. Trout; D. L. Bjorneberg; J. K. Aase

224

Late complications after application of polyacrylamide hydrogel  

Microsoft Academic Search

Since 1994, a new filling material (polyacrylamide 5% hydrogel, composed of acrylamide, methylenbisacrylamide, tetramethylendiamine and distilled water) has been used by several surgeons in Bulgaria. The indications for the use of hydrogel as recommended by the manufacturer are as follows: treatment of depressions and wrinkles of the glabella, malar and upper lip region, lip augmentation, augmentation mammaplasty, phalloplasty, atrophy or

D. Evstatiev

2006-01-01

225

Polyacrylamide induced flocculation of a cement suspension  

Microsoft Academic Search

The use of cellulose, instead of asbestos, in the fibre cement composites manufacture, using the Hatschek process, reduces cement retention and makes necessary to use a flocculant which is crucial for the plant productivity. The use of different types and doses of polyacrylamides (PAM) as well as the addition process, have been studied to obtain an in-depth knowledge of floc

Carlos Negro; Luis M. Sánchez; Elena Fuente; Ángeles Blanco; Julio Tijero

2006-01-01

226

Adsorption of polyacrylamides on mineral surfaces  

Microsoft Academic Search

The adsorption of neutral and hydrolyzed polyacrylamides, which are currently used in enhanced oil recovery, on minerals the surfaces of which carry silanol and aluminol groups such as siliceous minerals and akolinite is studied. All experiments are conducted in batch on powdered minerals. The conditions for the elimination of detrimental effects of both mechanical degradation of polymers and flocculation of

J. Lecourtier; L. T. Lee; G. Chauveteau

1987-01-01

227

Polyacrylamide Transport in Water Delivery Canals  

Microsoft Academic Search

Linear, anionic polyacrylamide (PAM) is being considered in the western United States as a technology to reduce seepage in unlined water delivery canals. A broad laboratory and field testing program has been undertaken to understand the benefits and potential environmental impacts of PAM use. The ability to predict the fate and transport of PAM in water delivery canals could prove

L. Chen; J. Zhu; M. Young

2007-01-01

228

Hybrid Gel Composed of Native Heart Matrix and Collagen Induces Cardiac Differentiation of Human Embryonic Stem Cells without Supplemental Growth Factors  

PubMed Central

Our goal was to assess the ability of native heart extracellular matrix (ECM) to direct cardiac differentiation of human embryonic stem cells (hESCs) in vitro. In order to probe the effects of cardiac matrix on hESC differentiation, a series of hydrogels was prepared from decellularized ECM from porcine hearts by mixing ECM and collagen type I at varying ratios. Maturation of cardiac function in embryoid bodies formed from hESCs was documented in terms of spontaneous contractile behavior and the mRNA and protein expression of cardiac markers. Hydrogel with high ECM content (75% ECM, 25% collagen, no supplemental soluble factors) increased the fraction of cells expressing cardiac marker troponin T, when compared with either hydrogel with low ECM content (25% ECM, 75% collagen, no supplemental soluble factors) or collagen hydrogel (100% collagen, with supplemental soluble factors). Furthermore, cardiac maturation was promoted in high-ECM content hydrogels, as evidenced by the striation patterns of cardiac troponin I and by upregulation of Cx43 gene. Consistently, high-ECM content hydrogels improved the contractile function of cardiac cells, as evidenced by increased numbers of contracting cells and increased contraction amplitudes. The ability of native ECM hydrogel to induce cardiac differentiation of hESCs without the addition of soluble factors makes it an attractive biomaterial system for basic studies of cardiac development and potentially for the delivery of therapeutic cells into the heart.

Duan, Yi; Liu, Zen; O'Neill, John; Wan, Leo Q.; Freytes, Donald O.; Vunjak-Novakovic, Gordana

2011-01-01

229

Polyacrylamide+Al 2(SO 4) 3 and polyacrylamide+CaO remove coliform bacteria and nutrients from swine wastewater  

Microsoft Academic Search

Animal wastes are a major contributor of nutrients and enteric microorganisms to surface water and ground water. Polyacrylamide (PAM) mixtures are an effective flocculent, and we hypothesized that they would reduce transport of microorganisms in flowing water. After waste water running at 60.0 l min?1 flowed over PAM+Al2(SO4)3, or PAM+CaO in furrows, total coliform bacteria (TC) and fecal coliform bacteria

James A Entry; Ian Phillips; Helen Stratton; R. E Sojka

2003-01-01

230

[Electron microscopy study of artificial vitreous gel].  

PubMed

Artificial gels prepared from Cu2+-ions and hyaluronic acid were studied in the electron microscope and compared with the native vitreous body. Additionally, the authors attempted to produce transparent gels from the native constituents of the vitreous body, namely collagen and hyaluronic acid. Mixing of solutions of these constituents formed no gels but white precipitates. The ultrastructure of these precipitates was also studied in the electron microscope. PMID:3723971

Ehgartner, E M; Schmut, O; Hofmann, H

1986-04-01

231

Microfabricated Polyacrylamide Devices for the Controlled Culture of Growing Cells and Developing Organisms  

PubMed Central

The ability to spatially confine living cells or small organisms while dynamically controlling their aqueous environment is important for a host of microscopy applications. Here, we show how polyacrylamide layers can be patterned to construct simple microfluidic devices for this purpose. We find that polyacrylamide gels can be molded like PDMS into micron-scale structures that can enclose organisms, while being permeable to liquids, and transparent to allow for microscopic observation. We present a range of chemostat-like devices to observe bacterial and yeast growth, and C. elegans nematode development. The devices can integrate PDMS layers and allow for temporal control of nutrient conditions and the presence of drugs on a minute timescale. We show how spatial confinement of motile C. elegans enables for time-lapse microscopy in a parallel fashion.

Gude, Sebastian; Recouvreux, Pierre; van Zon, Jeroen S.; Tans, Sander J.

2013-01-01

232

One- and two-dimensional blue native-PAGE and immunodetection of low-abundance chloroplast membrane protein complexes.  

PubMed

Blue native polyacrylamide gel electrophoresis (BN-PAGE) is a powerful method for separating protein complexes from biological membranes under native conditions. BN-PAGE provides much higher resolution than gel filtration or sucrose density gradient centrifugation, and it can be used to estimate the molecular mass of protein complexes. First, membrane protein complexes need to be solubilized with a mild nonionic detergent such as digitonin or dodecyl maltoside. Coomassie brilliant blue G-250, a negatively charged dye that binds to the surface of the solubilized complexes, is then added so these can be resolved according to their size by non-denaturing (native) electrophoresis. BN-PAGE can be combined with a second dimension SDS-PAGE step (two-dimensional (2D)-BN/SDS-PAGE), so that the subunits making up these complexes are also separated according to their size. Here, we present our 2D-BN/SDS-PAGE method, and subsequent immunoblotting method, for the detection of relatively low-abundance proteins from plant chloroplasts. PMID:21863435

Kikuchi, Shingo; Bédard, Jocelyn; Nakai, Masato

2011-01-01

233

Quantification of viscoelastic effects of polyacrylamide solutions  

SciTech Connect

Beyond a critical rate of flow in cores the viscoelasticity of polyacrylamide solutions is reflected by shear thickening behaviour. Practical information is provided on the critical flow rate and magnitude of shear thickening and their dependency on core permeability, temperature, molecular weight and concentration of commercial polymers. To describe the onset of shear thickening, critical Deborah numbers were calculated using fluid relaxation times obtained by oscillation rheometry. Using three core-flow parameters, viz. the critical flow rate and two powerlaw exponents, the viscoelastic effects are quantified.

Heemskerk, J.; Holtslag, R.J.; Janssen-van Rosmalen, R.; Teeuw, D.

1984-04-01

234

Comparison between a polyacrylamide and a hydrophobically modified polyacrylamide flood in a sandstone core  

Microsoft Academic Search

Polymer flooding in oil reservoirs to enhance oil recovery (EOR) has been used worldwide. However, the polymers applied, such as partially hydrolyzed polyacrylamides and xanthan gum, show a number of limitations related to their low salt tolerance and biological degradation, respectively. Therefore, the polymeric properties must be improved to maximize their application. With this goal in mind, a new class

Ana M. S. Maia; Redouane Borsali; Rosangela C. Balaban

2009-01-01

235

Performance and biocompatibility of extremely tough alginate/polyacrylamide hydrogels.  

PubMed

Although hydrogels now see widespread use in a host of applications, low fracture toughness and brittleness have limited their more broad use. As a recently described interpenetrating network (IPN) of alginate and polyacrylamide demonstrated a fracture toughness of ?9000 J/m(2), we sought to explore the biocompatibility and maintenance of mechanical properties of these hydrogels in cell culture and in vivo conditions. These hydrogels can sustain a compressive strain of over 90% with minimal loss of Young's Modulus as well as minimal swelling for up to 50 days of soaking in culture conditions. Mouse mesenchymal stem cells exposed to the IPN gel-conditioned media maintain high viability, and although cells exposed to conditioned media demonstrate slight reductions in proliferation and metabolic activity (WST assay), these effects are abrogated in a dose-dependent manner. Implantation of these IPN hydrogels into subcutaneous tissue of rats for 8 weeks led to mild fibrotic encapsulation and minimal inflammatory response. These results suggest the further exploration of extremely tough alginate/PAAM IPN hydrogels as biomaterials. PMID:23896005

Darnell, Max C; Sun, Jeong-Yun; Mehta, Manav; Johnson, Christopher; Arany, Praveen R; Suo, Zhigang; Mooney, David J

2013-07-26

236

Increase in local protein concentration by field-inversion gel electrophoresis  

Microsoft Academic Search

BACKGROUND: Proteins that migrate through cross-linked polyacrylamide gels (PAGs) under the influence of a constant electric field experience negative factors, such as diffusion and non-specific trapping in the gel matrix. These negative factors reduce protein concentrations within a defined gel volume with increasing migration distance and, therefore, decrease protein separation efficiency. Enhancement of protein separation efficiency was investigated by implementing

Henghang Tsai; Teck Yew Low; Steve Freeby; Aran Paulus; Kalpana Ramnarayanan; Chung-pui Paul Cheng; Hon-chiu Eastwood Leung

2007-01-01

237

Increase in local protein concentration by field-inversion gel electrophoresis  

PubMed Central

Background Proteins that migrate through cross-linked polyacrylamide gels (PAGs) under the influence of a constant electric field experience negative factors, such as diffusion and non-specific trapping in the gel matrix. These negative factors reduce protein concentrations within a defined gel volume with increasing migration distance and, therefore, decrease protein separation efficiency. Enhancement of protein separation efficiency was investigated by implementing pulsed field-inversion gel electrophoresis (FIGE). Results Separation of model protein species and large protein complexes was compared between FIGE and constant field electrophoresis (CFE) in different percentages of PAGs. Band intensities of proteins in FIGE with appropriate ratios of forward and backward pulse times were superior to CFE despite longer running times. These results revealed an increase in band intensity per defined gel volume. A biphasic protein relative mobility shift was observed in percentages of PAGs up to 14%. However, the effect of FIGE on protein separation was stochastic at higher PAG percentage. Rat liver lysates subjected to FIGE in the second-dimension separation of two-dimensional polyarcylamide gel electrophoresis (2D PAGE) showed a 20% increase in the number of discernible spots compared with CFE. Nine common spots from both FIGE and CFE were selected for peptide sequencing by mass spectrometry (MS), which revealed higher final ion scores of all nine protein spots from FIGE. Native protein complexes ranging from 800 kDa to larger than 2000 kDa became apparent using FIGE compared with CFE. Conclusion The present investigation suggests that FIGE under appropriate conditions improves protein separation efficiency during PAGE as a result of increased local protein concentration. FIGE can be implemented with minimal additional instrumentation in any laboratory setting. Despite the tradeoff of longer running times, FIGE can be a powerful protein separation tool.

Tsai, Henghang; Low, Teck Yew; Freeby, Steve; Paulus, Aran; Ramnarayanan, Kalpana; Cheng, Chung-pui Paul; Leung, Hon-chiu Eastwood

2007-01-01

238

RNA conformational changes analyzed by comparative gel electrophoresis.  

PubMed

The study of biologically relevant native RNA structures is important to understand their cellular function(s). Native gel electrophoresis provides information about such native structures in solution as a function of experimental conditions. The application of native gel electrophoresis in a comparative manner allows to obtain precise information on relative angles subtended between given pair of stems in an RNA molecule. By adapting this approach, it is possible to obtain very specific structural information such as the amplitude of dihedral angles and helical rotation. As an example, we will describe how native gel electrophoresis can be used to study the folding of the S-adenosylmethionine (SAM) sensing riboswitch. PMID:24136609

Eschbach, Sébastien H; Lafontaine, Daniel A

2014-01-01

239

Immobilization of laccase on polyacrylamide and polyacrylamide - ? - carragennan-based semi-interpenetrating polymer networks.  

PubMed

In this study, laccase enzyme (L) from Agaricus bisporus was immobilized by entrapment into polyacrylamide (PAAm) and semi-interpenetrating polymer networks (semi-IPNs) prepared with either polyacrylamide/?-carragennan (0.05g) [PAAm/ ?-car (0.05)] or polyacrylamide/?-carragennan (0.1 g) [PAAm/ ?-car (0.1)]. The optimum pH was 6.0 for free L, 8.0 for PAAm-L, 8.5 for PAAm/?-car (0.05)-L, and 9.0 for PAAm/?-car (0.1)-L. The optimum temperature was determined as 45°C for free L and 60°C for all immobilized laccases. After 27 days of storage at 4°C, free enzyme lost its initial activity whereas immobilized enzymes retained 56 % (-)80% of their initial activities. The immobilized samples were used repeatedly 35 times by retaining 28 %-58 % of their initial activity. K(m(app)) values were calculated as 0.088, 0.139, 0.133, and 0.131 mM and Vmax values were found to be 2.83 x 10(-3), 4.51×10(-3), 4.76×10(-3), and 4.97×10(-3) mM min(-1) for free L and PAAm-L, PAAm/?-car (0.05)-L, and PAAm/?-car (0.1)-L, respectively. PMID:22594636

Gökgöz, M; Altinok, H

2012-05-17

240

Combination of native and denaturing PAGE for the detection of protein binding regions in long fragments of genomic DNA.  

PubMed

In traditional electrophoresis mobility shift assay (EMSA) a single (32)P-labeled double-stranded DNA oligonucleotide or a restriction fragment bound to a protein is separated from the unbound DNA by polyacrylamide gel electrophoresis (PAGE) under nondenaturing conditions. An extension of this method uses a population of DNA restriction fragments derived from long genomic regions for the identification of fragments containing protein binding regions. Although the method allows simultaneous analysis of large fragments, it is relatively laborious and can be used to detect only fragments containing high affinity protein binding sites. Here we describe an alternative and straightforward strategy which is based on a combination of native and denaturing PAGE. With this strategy restriction fragments, derived from genomic DNA (<10 kb), containing high as well as low affinity protein binding regions may be easily identified. PMID:23436361

Kaer, Kristel; Speek, Mart

2013-01-01

241

Improved polyacrylamide treatments for water control in producing wells  

SciTech Connect

This paper reports on two polyacrylamide processes for water control in producing wells which improve the efficiency of conventional polyacrylamide treatment without inducing any risk of well plugging by crosslinkers. Treatment of a gas-storage well strongly decreased water production without any adverse effect on gas injection or production for at least 3 years.

Zaltoun, A.; Kohler, N. (Inst. Francais du Petrole (FR)); Guerrini, Y. (Gaz de France (FR))

1991-07-01

242

The effect of flow rate on the in-situ gelation of a chrome/redox/polyacrylamide system  

SciTech Connect

This paper presents experimental data on the gelation of a polyacrylamide/thiourea/Cr(VI) gel system in unconsolidated sandpacks at flow rates typical of those encountered beyond the immediate vicinity of a wellbore. At these low rates, in-situ gelation during flow was characterized by an abrupt increase in flow resistance that occurred over a short distance at a specific location along the sandpack. The location of this region was a function of flow rate, and its distance from the inlet increased as flow rate increased. Filtration of gel aggregates appears to be the mechanism causing this behavior.

Marty, L.; Green, D.W.; Willhite, G.P. (University of Kansas (US))

1991-05-01

243

Effect of ?-carrageenan on volume phase transition for polyacrylamide (PAAm) hydrogel using the fluorescence technique  

NASA Astrophysics Data System (ADS)

Steady-state fluorescence (SSF) technique was employed for studying swelling of polyacrylamide (PAAm) gels with various content of ?-carrageenan (?C). Disc shaped composite hydrogels were prepared by free-radical crosslinking copolymerization of acrylamide (AAm) with various amounts ?C. N,N'-methylenebis (acrylamide) (BIS) and ammonium persulfate (APS) were used as crosslinker and initiator, respectively. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine was monitored during in situ swelling processes of composite gels. It was observed that fluorescence intensity values decreased as swelling is proceeded. Li-Tanaka equation was used to determine the swelling time constants, ? and cooperative diffusion coefficients, D from intensity variations during the swelling processes. It was shown that swelling time constants, ? decreased and diffusion coefficients, D increased as the ?C content in the composites are increased.

Akta?, Demet Kaya

2013-06-01

244

Native Americans  

NSDL National Science Digital Library

Native Americans are made up of many fascinating groups of people with multiple cultures. We will explore the main cultural areas of these groups. We will describe and compare some of these groups of people such as Eastern Woodlands, Plains, Great Basin, Southwestern, Arctic, Northwest, Incan, Aztec, and Mayan. We will also identify how these people maintain their cultural traditions today. We will explore each of this interesting cultures and take notes as we explore with individualized graphic organizers. Learning about Native Americans Woodland Tribes Great Plains Tribes Great Basin Native Americans Northwest Southwest Aztec, Mayans Inca BRAINTEASER The Inca Trail and Machu Picchu Glossary Links ...

Keller, Mrs.

2009-06-12

245

Photoswitchable gel assembly based on molecular recognition.  

PubMed

The formation of effective and precise linkages in bottom-up or top-down processes is important for the development of self-assembled materials. Self-assembly through molecular recognition events is a powerful tool for producing functionalized materials. Photoresponsive molecular recognition systems can permit the creation of photoregulated self-assembled macroscopic objects. Here we demonstrate that macroscopic gel assembly can be highly regulated through photoisomerization of an azobenzene moiety that interacts differently with two host molecules. A photoregulated gel assembly system is developed using polyacrylamide-based hydrogels functionalized with azobenzene (guest) or cyclodextrin (host) moieties. Reversible adhesion and dissociation of the host gel from the guest gel may be controlled by photoirradiation. The differential affinities of ?-cyclodextrin or ?-cyclodextrin for the trans-azobenzene and cis-azobenzene are employed in the construction of a photoswitchable gel assembly system. PMID:22215078

Yamaguchi, Hiroyasu; Kobayashi, Yuichiro; Kobayashi, Ryosuke; Takashima, Yoshinori; Hashidzume, Akihito; Harada, Akira

2012-01-03

246

21 CFR 872.3480 - Polyacrylamide polymer (modified cationic) denture adhesive.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Polyacrylamide polymer (modified cationic) denture adhesive...Devices § 872.3480 Polyacrylamide polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture...

2013-04-01

247

21 CFR 872.3420 - Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture adhesive.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture... § 872.3420 Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture...Identification. A carboxymethylcellulose sodium and cationic polyacrylamide polymer...

2013-04-01

248

Molecular recognition in gels, monolayers, and solids  

NASA Astrophysics Data System (ADS)

This paper describes work in four areas: affinity electrophoresis of carbonic anhydrase in cross-linked polyacrylamide derived gels containing immobilized derivatives of aryl sulfonamides; inhibition of the hemagglutination of erythrocytes induced by influenza virus using water-soluble polyacrylamides bearing sialic acid groups; the application of self-assembled monolayers (SAMs) of alkyl thiolates on gold to the study of protein adsorption on organic surfaces; and the use of networks of hydrogen bonds to generate new classes of non-covalently assembled organic materials, both in solution and in crystals. This paper summarizes research in two areas of molecular recognition: affinity polymers and molecular self assembly. We illustrate these areas by examples drawn from affinity gel electrophoresis, soluble synthetic macromolecular inhibitors of binding of influenza virus to erythrocytes protein adsorption on self assembled monolayers and self assembling hydrogen bonded molecular aggregates.

Prime, Kevin L.; Chu, Yen-Ho; Schmid, Walther; Seto, Christopher T.; Chen, James K.

1991-12-01

249

Hydraulic fracturing process using a polymer gel  

SciTech Connect

This patent describes a fracturing process applied to a subterranean hydrocarbon-bearing formation below an earthen surface in fluid communication with a wellbore comprising: (a) premixing a fracturing fluid at the surface comprising a gel breaker and a gelation solution consisting essentially of an aqueous solvent, a water-soluble acrylamide polymer selected from the group consisting of polyacrylamide and partially hydrolyzed polyacrylamide, and a crosslinking agent formed of at least one chromium III species complexed with at least one carboxylate species selected from the group consisting of propionate, acetate, lactate, and mixtures thereof; (b) at least partially gelling the gelation solution at the surface to form a gel; and (c) injecting the fracturing fluid into the formation via the wellbore at a pressure sufficient to hydraulically fracture the formation.

Sydansk, R.D.

1988-10-25

250

In situ grouting of buried transuranic waste with polyacrylamide  

SciTech Connect

This project is a demonstration and evaluation of the in situ hydrologic stabilization of buried transuranic waste at a humid site via grout injection. Two small trenches, containing buried transuranic waste, were filled with 34.000 L of polyacrylamide grout. Initial field results have indicated that voids within the trenches were totally filled by the grout and that the intratrench hydraulic conductivity was reduced to below field-measurable values. No evidence of grout constituents were observed in twelve perimeter groundwater monitoring wells indicating that grout was contained completely within the two trenches. Polyacrylamide grout was selected for field demonstration over the polyacrylate grout due to its superior performance in laboratory degradation studies. Also supporting the selection of polyacrylamide was the difficulty in controlling the set time of the acrylate polymerization. Based on preliminary degradation monitoring, the polyacrylamide was estimated to have a microbiological half-life of 362 years in the test soil. 15 refs., 9 figs., 12 tabs.

Spalding, B.P.; Lee, S.Y.; Farmer, C.D.; Hyder, L.K.; Supaokit, P.

1987-01-01

251

Petroleum recovery process utilizing formaldehyde-sulfite-reacted polyacrylamide  

Microsoft Academic Search

Micellar slugs followed by thickened water floods were injected into Berea cores (20.4 percent porosity, 398.4 md permeability, see Patent 3,692,113 for pretreatment) for enhanced oil recovery. About 61.1 percent residual oil was produced when the polymer in the thickened water was sulfomethylated hydrolyzed polyacrylamide. However, use of the conventional unhydrolyzed polyacrylamide recovered only 27.7 percent residual oil.

C. J. Norton; D. O. Falk

1973-01-01

252

Dynamic Light-Scattering Evidence for the Flexibility of Native Muscle Thin Filaments  

PubMed Central

We have obtained clear evidence for the flexibility of native scallop adductor thin filaments by studying the temperature and ionic strength dependence of the average decay constants obtained from intensity fluctuation spectroscopic (IFS) measurements. The low-angle (10-25°), average decay constants obtained from time autocorrelation functions of scattered light were independent of concentration (0.08-1.3 mg/ml), scaled with the ratio of temperature to solvent viscosity, T/?, over a range of 4-45°C, and yielded a value for the translational diffusion coefficient of DT5°C = (1.24 ± 0.06) × 10-8 cm2/s. From this value and the Broersma relation for rigid rods, we find an average filament length of 1.06 ± 0.06 ?m. Quantitative sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that at high temperatures (> 35°C) or in 0.6 M NaCl, tropomyosin completely dissociates from native thin filaments. Decay constants from high-angle (60-150°C) IFS temperature dependence measurements do not scale with T/? and hence do not show the temperature dependence expected for rigid rods. The differences are not due to any change in length distribution of filaments with temperature or to the free tropomyosin in solution, but are attributed to nonrigid motions of the filaments. Similar experiments on samples in high- and low-salt solvents gave results consistent with this interpretation.

Newman, Jay; Carlson, Francis D.

1980-01-01

253

Gel placement in fractured systems  

SciTech Connect

This paper examines several factors that can have an important effect on gel placement in fractured systems, including gelant viscosity, degree of gelation, and gravity. For an effective gel treatment, the conductivity of the fracture must be reduced and a viable flow path must remain open between the wellbore and mobile oil in the reservoir. During placement, the gelant that``leaks off`` from the fracture into the rock plays an important role in determining how well a gel treatment will reduce channeling. For a given volume of gelant injected the distance of gelant leakoff is greater for a viscous gelant than for a low-viscosity gelant. In one method to minimize gelant leakoff, sufficient gelation is designed to occur before the gelant leaves the wellbore. The authors investigated this approach in numerous experiments with both fractured and unfractured cores. They studied Cr(III)/acetate/hydrolyzed polyacrylamide (HPAM), resorcinol/formaldehyde, Cr(III)/xanthan, aluminum/citrate/HPAM, and other gelants and gels with various delay times between gelant preparation and injection. Their results suggest both hope and caution concerning the injection of gels into fractured systems.

Seright, R.S. [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States)

1995-11-01

254

Analysis of protein glycation using phenylboronate acrylamide gel electrophoresis  

Microsoft Academic Search

The incorporation of the specialized carbohydrate affinity ligand methacrylamido phenylboronic acid in polyacrylamide gels for SDS-PAGE analysis has been successful for the separation of carbohydrates and has here been adapted for the analysis of post-translationally modified proteins. While conventional SDS-PAGE analysis cannot distinguish between glycated and unglycated proteins, methacrylamido phenylboronate acrylamide gel electrophoresis (mP-AGE) in low loading shows dramatic retention

Marta P. Pereira Morais; Julia D. Mackay; Savroop K. Bhamra; J. Grant Buchanan; T. D. James; John S. Fossey; Jean M. H. van den Elsen

2010-01-01

255

Acrylamide-Gel Electrophorograms by Mechanical Fractionation: Radioactive Adenovirus Proteins  

Microsoft Academic Search

A mechanical fractionator was developed to produce electrophorograms by extrusion of polyacrylamide gels through a narrow orifice in a continuous, sequential stream. The system permits separation of uniform fractions free of zone distortion. An electrophorogram of radioactive type-2 adenovirus proteins so fractionated gave a pattern in excellent agreement with the pattern obtained by laborious manual sectioning and in agreement with

Jacob V. Maizel Jr.

1966-01-01

256

Measurements of Elastic Moduli of Silicone Gel Substrates with a Microfluidic Device  

Microsoft Academic Search

Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple

Edgar Gutierrez; Alex Groisman; Jörg Langowski

2011-01-01

257

Apolipoprotein E phenotyping with a single gel method: application to the study of informative matings  

Microsoft Academic Search

Two-dimensional gel electrophoresis or isoelectric focusing before and after treatment with cysteamine are cur- rently used to determine the six apolipoprotein E isomorphic phenotypes from isolated very low density lipoproteins. A technique is described that makes this possible by performing isoelectric focusing on a single polyacrylamide cylindrical gel under standardized conditions. The technique is simple and accurate enough to obtain

Daniel Bouthillier; Charles F. Sing; Jean Davignon

258

Effect of gypsum and polyacrylamides on water turbidity and infiltration in a sodic soil  

Microsoft Academic Search

Water ponded on sodic soils can develop turbidity problems which seriously affect rice crop establishment. A total of 19 polyacrylamide products were assessed for their effectiveness to control water turbidity in a sodic soil under laboratory conditions. Anionic polyacrylamides were more effective than cationic or non- ionic polyacrylamides. When combined with gypsum, polyacrylamides were found to be more effective than

S. Sivapalan

2005-01-01

259

Native Intelligence  

ERIC Educational Resources Information Center

|Amid concerns from tribal leaders that No Child Left Behind testing is squeezing out electives that have traditionally covered their history and cultures, an ambitious brace of programs is making Native America part of the core curriculum at David Wolfle Elementary School and other schools in the western Washington State. By tapping into…

Seven, Richard

2006-01-01

260

Photo- and electroactive color changeable acrylamide gel actuator  

NASA Astrophysics Data System (ADS)

Polyacrylamide hydrogels containing bis-[4- {dimethylamine}phenyl]{4-vinyl-phenyl}methyl leucohydroxide which is so called vinyl derivative of Malachite Green have been studied as color changeable gels. The response times of the color and the volume changes of the gel were measured under 6 and 2 different stimuli, respectively. We found a way to increase their color change speed upon applied electric current (E-current), and designed a gel actuator using Nafion film as a separator between two compartments and as a cation conductor. In addition acrylamide gel swollen with Na2SO4 solution was used as a medium for increasing electric conductivity. We varied the concentration of dvMG in the gel to control the degree of color change. Furthermore, we have studied the influence of gel thickness on the color change rate. In light of the results obtained, we have proposed one device consisting of this color changeable gel.

Xu, Chunye; Tamagawa, Hirohisa; Uchida, Mikio; Popovic, Suzana; Taya, Minoru

2001-07-01

261

Native American Spirituality  

Microsoft Academic Search

Followers of the New Age movement and others have been exploiting and commercializing “Native American” spirituality. This exploitation is being fought by many Native people. Native American spirituality may be studied and appreciated, but use of Native American religious forms outside of Native American communities is considered misappropriation and cultural theft. Native spiritualities address the needs of present-day Native communities.

Cynthia A. Snavely

2001-01-01

262

Immobilized electric eel acetylcholinesterase. I. Kinetics of acetylcholinesterase trapped in polyacrylamide membranes.  

PubMed

Techniques are described for the trapping of electric eel acetylcholinesterase in polyacrylamide gel. The activity of the trapped enzyme was substantially reduced, the effect being due to inhibition by acrylamide, but the emzyme immobilized in polyacrylamide was considerable more stable than that in free solutionma kinetic study was made of the hydrolysis of acetylthiocholine, covering a range of membrane thicknesses, enzyme concentrations, substrate concentrations and temperatures. The results were interpreted with reference to the theoretical treatment of Sundaram, Tweedale and Laidler, and of Kobayaski and Laidler, and provided support for those treatments; Clear evidence was obtained for diffusion control with the thicker membranes. An activation energy was obtained for the diffusion of the substrate within the membrane, by combining the temperature results for thick and thin membranes at low substrate concentrations. The results lead to the conclusion that the in vivo kinetics of acetylcholinesterase are largely diffusion-free in muscle filaments, but are substantially diffusion-controlled in fibrils and fibers. PMID:1168074

Ngo, T T; Laidler, K J

1975-02-19

263

Transfer of Proteins from Gels to Diazobenzyloxymethyl-Paper and Detection with Antisera: A Method for Studying Antibody Specificity and Antigen Structure  

Microsoft Academic Search

We describe a rapid and very sensitive method for detecting proteins as antigens after their separation in polyacrylamide\\/agarose composite gels, with or without sodium dodecyl sulfate. The polyacrylamide matrix is crosslinked with a reagent that can be cleaved with periodate or alkali to facilitate transfer of the protein bands to diazobenzyloxymethyl-paper, where they are coupled covalently. Specific proteins are detected

Jaime Renart; Jakob Reiser; George R. Stark

1979-01-01

264

A Novel Use for Coomassie Brilliant Blue (R-250) In Protein Gel-Drying Procedure and Assessing the Electro-Transferring Efficiency  

Microsoft Academic Search

The present study provides an alternative method for protein-gel drying. Rat brain protein extracts were separated using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) followed by staining with coomassie brilliant blue (R-250). The stained gel was then subjected to electroblotting on nitrocellulose membranes. This method exhibited four advantages: 1) it eliminated problems associated with gel-drying (e.g., shrinkage of gel), 2) it

Adnan I. Dibas; Thomas Yorio

1996-01-01

265

A simple method of eluting proteins from two-dimensional gels  

SciTech Connect

Apo A-I lipoprotein was extracted from the appropriate pieces of two-dimensional gel patterns, by electrophoresis onto hydroxylapatite overlaying a slab of polyacrylamide sodium dodecyl sulfate gel. The extracted protein was then eluted from the hydroxylapatite by washing with increasing concentrations of phosphate buffer. The recovered protein was electrophoretically homogeneous. We believe that this method can be generally useful in the purification, for study, of proteins identified on two-dimensional gels as putative markers of disease.

Guevara, J. (Texas Medical Center, Houston); Chiocca, E.A.; Clayton, F.C.; von Eschenbach, A.C.; Edwards, J.J.

1982-01-01

266

Diffusive transfer to membranes as an effective interface between gel electrophoresis and mass spectrometry  

Microsoft Academic Search

Diffusive transfer was examined as a blotting method to transfer proteins from polyacrylamide gels to membranes for ultraviolet matrix-assisted laser desorption ionization (MALDI) mass spectrometry. The method is well-suited for transfers from isoelectric focusing (IEF) gels. Spectra have been obtained for 11 pmol of 66 kDa albumin loaded onto an IEF gel and subsequently blotted to polyethylene. Similarly, masses of

Rachel R. Ogorzalek Loo; Charles Mitchell; Tracy I. Stevenson; Joseph A. Loo; Philip C. Andrews

1997-01-01

267

Adsorption of polyacrylic acid and polyacrylamide on montmorillonite  

NASA Astrophysics Data System (ADS)

The effect of process duration, temperature, and concentration on the adsorption of polyacrylic acid and polyacrylamide by montmorillonite is studied. It is shown that the pattern of interaction of the studied polyelectrolytes with the sorbent surface is determined by the nature of the polymers, the prevalence of acid-base sites, and the pore structure of the mineral.

Akimkhan, A. M.

2013-11-01

268

Controls on polyacrylamide adsorption to quartz, kaolinite, and feldspar  

NASA Astrophysics Data System (ADS)

Potentiometric titrations of quartz, kaolinite, feldspar, and partially hydrolysed polyacrylamide (HPAM), and sorption measurements of HPAM on the minerals, allows identification of the general mechanisms of polyacrylamide adsorption to aluminosilicates and quartz. Adsorption was monitored at the mineral solution interface by way of X-ray photoelectron spectroscopy (XPS). XPS spectra of the unreacted minerals show bands in the Ols, Si2p, Al2p, and Cls regions. Additional peaks are observed in the C1s and N1s regions after treatment with polyacrylamide and the latter is used in this study to monitor polymer adsorption. N1s peak intensities increase with polymer concentration to a maximum corresponding to surface site saturation. At a fixed polymer concentration, adsorption varies with pH-dependent surface charge. The adsorption mechanism changes with pH, reflecting variation in the pH-dependent concentrations of ionizable groups on polyacrylamide and at aluminosilicate surfaces, and the extent of hydrogen-bonding between uncharged mineral surface sites and polymer amide groups.

Graveling, Gary J.; Vala Ragnarsdottir, K.; Allen, Geoff C.; Eastman, John; Brady, Patrick V.; Balsley, Steven D.; Skuse, David R.

1997-09-01

269

REACTIVE EXTRUSION OF STARCH-POLYACRYLAMIDE GRAFT COPOLYMERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Graft copolymers of starch and polyacrylamide have been prepared using a twin screw extruder. The effects of initiator type and concentration, moisture content, and starch/monomer ratio on conversion, graft efficiency, graft molecular weight, and frequency of grafting are discussed. Conversion of ...

270

Polyacrylamide Polymer Viscosity as a Function of Brine Composition.  

National Technical Information Service (NTIS)

A computer model has been developed which predicts the viscosity of polymer and oil field brine mixtures. The polymers used were Amoco- Sweepaid 103 and Dow- Pusher 500 polyacrylamide polymers. All of the experiments were conducted at 1200 ppM polymer con...

A. G. Collins N. Stacy T. R. French

1981-01-01

271

HRP-Mediated Synthesis of Starch-Polyacrylamide Graft Copolymers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Modified starch-based polymers can be engineered for specific properties by combining starch with synthetic polymers through graft copolymerization. Polyacrylamide grafted starch have received a great deal of applications in areas such as superabsorbent paper-making additives, drag reduction and te...

272

Dissolution Characteristics of Hydrophobically Associating Polyacrylamide in Stirred Tanks  

Microsoft Academic Search

Enhanced oil recovery (EOR) by means of polymer flooding is an important technology for the strategic development of offshore oilfields in China. Hydrophobically associating polyacrylamide (HAPAM) has been recently proposed as a new flooding agent. The solubility of HAPAM is low, which is the bottleneck for further improving the oil recovery through polymer flooding in offshore oilfield. Stirred tanks have

Guozhong ZHOU; Minghui XIE; Min LIU; Huaxiao WU; Xiangli LONG; Peiqing YU

2010-01-01

273

SOLVENT EFFECTS ON THE RHEOLOGY OF AQUEOUS POLYACRYLAMIDE SOLUTIONS†  

Microsoft Academic Search

The influence of solvent chemistry on steady shear viscosity and first normal stress difference for aqueous polyacrylamide solutions (Separan AP-273) was investigated in the Weissenberg rheogoniometer and capillary tube viscometer. It was found that these rheological properties are particularly sensitive to the chemistry of the solvent. For example, the zero shear rate viscosity of a 1000 wppm Separan solution with

Y. I. CHO; J. P. HARTNETT; Y. S. PARK

1983-01-01

274

HRP-Mediated Synthesis of Starch-Polyacrylamide Graft Copolymers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Modified starch-based polymers can be engineered for specific properties by combining starch with synthetic polymers through graft copolymerization. Polyacrylamide grafted starches have received a great deal of applications in areas such as superabsorbent paper-making additives, drag reduction and ...

275

MULTIPLE POLYACRYLAMIDE APPLICATIONS FOR CONTROLLING SPRINKLER IRRIGATION RUNOFF AND EROSION  

Microsoft Academic Search

ABSTRACT. Runoff under sprinkler irrigation systems causes soil erosion and reduces water infiltration uniformity. Previous studies have shown that applying polyacrylamide,(PAM) with irrigation water can reduce runoff and soil loss. We hypothesized that applying PAM with three consecutive irrigations would more effectively control runoff and erosion than applying the same total amount,of PAM with a single irrigation. This study was

D. L. Bjorneberg; J. K. Aase

2000-01-01

276

FACTORS AFFECTING THE EFFICIENT FLOCCULATION OF TAILINGS BY POLYACRYLAMIDES  

Microsoft Academic Search

The flocculation of coal preparation plant tailings is an established technology, and the scientific basis of flocculation is well understood, Nevertheless, conditions specific to the preparation plant affect the efficiency of the process. The sedimentation rate obtained with flocculated tailings depends on the molecular size of the polyacrylamide. Modern flocculants are very high molecular weight polymers and the size of

J. M. HENDERSON; A. D. WHEATLEY

1987-01-01

277

Ultrasensitive Stain for Proteins in Polyacrylamide Gels Shows Regional Variation in Cerebrospinal Fluid Proteins  

NASA Astrophysics Data System (ADS)

A new silver stain for electrophoretically separated polypeptides can be rapidly and easily used and can detect as little as 0.01 nanogram of protein per square millimeter. When employed with two-dimensional electrophoresis, it should permit qualitative and quantitative characterization of protein distributions in body fluids and tissues. It has been used to demonstrate regional variations in cerebrospinal fluid proteins.

Merril, Carl R.; Goldman, David; Sedman, Sylvia A.; Ebert, Michael H.

1981-03-01

278

Identification of Tissue-Specific Nuclear Antigens Transferred to Nitrocellulose from Polyacrylamide Gels  

Microsoft Academic Search

Nonhistone protein antigens resolved by electrophoresis in sodium dodecyl sulfate were identified immunochemically after being transferred to nitrocellulose. Use of antiserum to dehistonized chromatin from Novikoff hepatoma revealed numerous protein antigens specific to the chromatin of Novikoff hepatoma in comparison to that of normal rat liver.

William F. Glass; Robert C. Briggs; Lubomir S. Hnilica

1981-01-01

279

Loop-mediated isothermal amplification of a single DNA molecule in polyacrylamide gel-based microchamber  

Microsoft Academic Search

Loop-mediated isothermal amplification (LAMP) is an original nucleic acid amplification method established by Notomi et al.\\u000a LAMP is performed under isothermal condition, employing only a basic reaction protocol and minimal supporting electronics.\\u000a These requirements prove to be viable for exploring the avenues to down-scale this biological reaction for Lab-on-a-chip application.\\u000a Hence here, we developed a novel technique for fluorescent imaging

Liza Lam; Shouichi Sakakihara; Koji Ishizuka; Shoji Takeuchi; Hideyuki F. Arata; Hiroyuki Fujita; Hiroyuki Noji

2008-01-01

280

Disc polyacrylamide gel electrophoresis of pollen proteins in the oil palm (Elaeis)  

Microsoft Academic Search

A preliminary screening of proteins and isozymes in the oil palm was investigated with a view to using the data in discriminating oil palm fruit forms. Protein and enzyme staining was carried out using pollen tissue. Repeatable bands of proteins which showed reproducable variation in banding patterns were obtained. Low percentage similarities between the groups compared for protein banding patterns

C. D. Ataga; C. A. Fatokun

1989-01-01

281

Detection of phosphorylated T and B cell antigen receptor species by Phos-tag SDS- and Blue Native-PAGE.  

PubMed

Detection of phospho-proteins and differently phosphorylated forms of the same protein are important in understanding cell behaviour. One novel method is Phos-tag SDS-PAGE. A dinuclear Mn(2+) complex that binds to phosphate groups (the Phos-tag) is covalently attached to the polyacrylamide gel matrix. Thus, phosphorylated proteins are retarded in their migration and can be distinguished from their non-phosphorylated counterparts. We applied Phos-tag SDS-PAGE to the analysis of the zeta, CD3epsilon and CD3delta subunits of the T cell antigen receptor (TCR-CD3). Pervanadate stimulation generated six different phospho-zeta and each two different CD3epsilon and CD3delta forms. This corresponds to the phosphorylatable tyrosines on their cytoplasmic tails. The phosphorylation pattern was compatible with random phosphorylation events. Further, we showed that the Phos-tag technology can be applied to Blue Native (BN)-PAGE. This extends the applicability to the analysis of native protein complexes. Upon pervanadate stimulation the TCR-CD3 complex was predominantly detected as two distinct phospho-complexes. In contrast, the B cell antigen receptor (BCR) appeared as one phospho-form. Thus, Phos-tag BN-PAGE is useful for the analysis of different phosphorylation states of multiprotein complexes. PMID:20005898

Deswal, Sumit; Beck-García, Katharina; Blumenthal, Britta; Dopfer, Elaine P; Schamel, Wolfgang W A

2009-12-22

282

Electrochemical stimulation and control of electroactive polymer gels  

NASA Astrophysics Data System (ADS)

Direct effects of electrical currents on polyelectrolyte gels are always associated with changes in their Donnan potential. Thus electrical stimulation of gels can be only completely understood if the direct effect of electric fields on the potential profile within the gels are known. The purpose of this study is to present recordings of Donnan potentials in electroactive gels of various compositions, especially under the influence of electric fields. An important finding is that opposite alterations in the Donnan potential simultaneously occur at the current inflow and outflow region of the gel. In anionic gels hyperpolarization, i.e. higher negativity, is induced on the anode-side of the gel, whereas depolarization is found on the cathode-side. As these shifts in the potential are supposed to affect swelling or deswelling of polyelectrolyte gels, they will primarily promote bending motions of the gel. To demonstrate the opposite bending behavior of anionic and cationic polymer gels under the influence of an electric field a short video sequence of an EAP gripper in action is presented. It is made exclusively of polyelectrolyte gel strips taking advantage of the fact that anionic and cationic polyacrylamide gels can be attached firmly to each other without any adhesive.

Guelch, Rainer W.; Holdenried, Jens; Weible, Andrea; Wallmersperger, Thomas; Kroeplin, Bernd

2001-07-01

283

The Effect of Polyacrylamide Molecular Structure on Flocculation Activity of Domestic Sewage.  

National Technical Information Service (NTIS)

Polyacrylamides have been shown to be effective flocculants resulting in increased efficiency in primary clarifiers in domestic waste treatment plants. The effectiveness of branched as opposed to linear anionic polyacrylamides at various hydrolysis and mo...

J. A. Caskey

1977-01-01

284

Analysis of Membrane Protein Complexes by Blue Native PAGE  

Microsoft Academic Search

Blue native polyacryamide gel electrophoresis is a special case of native electrophoresis for high resolution separa- tion of enzymatically active protein complexes from tissue homogenates and cell fractions. The method is powerful be- tween 10 and 10 000 kDa. Also membrane protein complexes are separated well after solubilization of complexes with mild neutral detergents. The separation principle relies on binding

Veronika Reisinger; Lutz Andreas Eichacker

2006-01-01

285

Restylane Injectable Gel (P040024/S051): Executive ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... 1. A history of allergy or hypersensitivity to injectable hyaluronic acid gel. ... 0 2 (1%) 2 (1%) Native Hawaiian or other Pacific Islander ... Page 40. ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

286

Equipment for dissolving polyacrylamide powder for obtaining an aqueous solution thereof for enhanced oil recovery  

Microsoft Academic Search

Equipment for dissolving polyacrylamide powder to obtain an aqueous solution thereof for enhanced oil recovery comprises first and second powder storage tanks for storing polyacrylamide powder under nitrogen atmosphere; a gas conveyor unit for carrying the polyacrylamide powder from the first storage tank to the second storage tank by nitrogen gas flow; a constant powder supply unit for receiving the

Y. Sekimoto; O. Okamoto

1985-01-01

287

Neutron insensitive depolymerization of polyacrylamide for californium-252 photon dosimetry  

Microsoft Academic Search

A photon dosimeter based on degradation of polyacrylamide (PAA) in dilute aqueous solution has been found to be insensitive to neutrons from Cf-252, independent of photon energy from 34 keVeff to 1.33 MeV, and useful over a dose range of 1 to 100 Gy. Because this dilute polymer solution is virtually 100% water, it is nearly tissue equivalent for photon

M. F. Moyers; J. L. Beach

2009-01-01

288

Neutron insensitive depolymerization of polyacrylamide for californium-252 photon dosimetry  

Microsoft Academic Search

A photon dosimeter based on degradation of polyacrylamide (PAA) in dilute aqueous solution has been found to be insensitive to neutrons from Cf-252, independent of photon energy from 34 keV\\/sub eff\\/ to 1.33 MeV, and useful over a dose range of 1 to 100 Gy. Because this dilute polymer solution is virtually 100% water, it is nearly tissue equivalent for

Michael F. Moyers; J. L. Beach

1982-01-01

289

Cationic polyacrylamides enhance rates of starch and cellulose saccharification  

Microsoft Academic Search

Adding a cationic polyacrylamide (c-PAM) to either the amylase mediated hydrolysis of corn starch or the hydrolysis of wood\\u000a fiber by cellulase can enhance the initial hydrolysis rates, although a rate decrease can occur under some conditions. Several\\u000a c-PAMs can serve as catalysts and the same c-PAM can improve the efficiency of both amylase and cellulase. The initial amylase\\u000a rate

John T. Reye; Kendra Maxwell; Swati Rao; Jian Lu; Sujit Banerjee

2009-01-01

290

Mechanism of formation of partially-crosslinked polyacrylamide complexes  

Microsoft Academic Search

A new type of partially-crosslinked polyacrylamide (PCPAM) which displays promising application in enhanced oil recovery (EOR) has been synthesized via aqueous solution polymerization under adiabatic conditions. Based on methods of real time infrared monitoring, two-dimensional infrared correlation spectroscopy and dynamic rheology measurement, an unusual complex formation mechanism of the PCPAM with the multi-functional initiator system is clearly disclosed. A process

Zhiqing Su; Zuming Jiang; Guangsu Huang; Li Li; Xiaoan Wang

2012-01-01

291

Synthesis and characterization of a series of modified polyacrylamide  

Microsoft Academic Search

We present the synthesis and the characterization of a new class of modified polyacrylamides (MPAM) with the unusual trait\\u000a of strong emulsification ability, viscosity enhancement capacity, and significant salt tolerance. Besides, the synthesized\\u000a polymers have the peculiar aggregation behaviors in aqueous solution. The synthesis was carried out by polymerizing the monomers\\u000a such as acrylamide (AM), acrylic acid (AA), unsaturated amphiphilic

Yuzhu Zhao; Jizhu Zhou; Xiaohui Xu; Wenbin Liu; Jingying Zhang; Minghong Fan; Jinben Wang

2009-01-01

292

Interactions of Polyacrylamide with Cationic Surfactants: Thermodynamic and Surface Parameters  

Microsoft Academic Search

The aggregation behaviour of two cationic surfactants, viz. cetyl trimethyl ammonium bromide (CTAB) and N-cetyl pyridinium\\u000a chloride (CPC), in different concentrations of water-soluble polyacrylamide has been studied in alkaline medium by electrical\\u000a conductivity and surface tension measurements. A decrease in the critical micelle concentration (CMC) of the surfactant with\\u000a an increase in polymer content in the mixture was observed. The

P. S. Niranjan; Ratna Shukla; Santosh K. Upadhyay

293

Sprinkler Irrigation Runoff and Erosion Control with Polyacrylamide — Laboratory Tests  

Microsoft Academic Search

ABSTRACT Many semiarid and arid soils are prone to irrigation-induced ero- sion. Polyacrylamide (PAM) greatly reduces erosion from furrow irrigation. We hypothesized that PAM applied via sprinklers will provide erosion control and benefit water infiltration and aggregate stability. Screened (6.4 mm) Rad silt loam (coarse silty, mixed, super- active mesic Durinodic Xeric Haplocambid) was placed in 1.5 by 1.2 by

J. Kristian Aase; David L. Bjorneberg; Robert E. Sojka

1998-01-01

294

The use of blue native PAGE in the evaluation of membrane protein aggregation states for crystallization.  

PubMed

Crystallization has long been one of the bottlenecks in obtaining structural information at atomic resolution for membrane proteins. This is largely due to difficulties in obtaining high-quality protein samples. One frequently used indicator of protein quality for successful crystallization is the monodispersity of proteins in solution, which is conventionally obtained by size exclusion chromatography (SEC) or by dynamic light scattering (DLS). Although useful in evaluating the quality of soluble proteins, these methods are not always applicable to membrane proteins either because of the interference from detergent micelles or because of the requirement for large sample quantities. Here, the use of blue native polyacrylamide gel electrophoresis (BN-PAGE) to assess aggregation states of membrane protein samples is reported. A strong correlation is demonstrated between the monodispersity measured by BN-PAGE and the propensity for crystallization of a number of soluble and membrane protein complexes. Moreover, it is shown that there is a direct correspondence between the oligomeric states of proteins as measured by BN-PAGE and those obtained from their crystalline forms. When applied to a membrane protein with unknown structure, BN-PAGE was found to be useful and efficient for selecting well behaved proteins from various constructs and in screening detergents. Comparisons of BN-PAGE with DLS and SEC are provided. PMID:19529836

Ma, Jichun; Xia, Di

2008-11-11

295

Accumulation of humic acid in DET/DGT gels.  

PubMed

Gel layer based sensors are increasingly employed for dynamic trace metal speciation analysis in aquatic and soil media. In DGT (Diffusive Gradient in Thin film), polyacrylamide hydrogels are commonly used for the diffusive gel layer. While some effects of humic and fulvic acids on the DGT detection of metal species have been observed, the gel permeation properties of the actual humic and fulvic acid compounds themselves have not been analyzed thus far. Here we show with DET (Diffusive Equilibrium in Thin film) that these natural complexing agents do enter the gel layer, and that humic acids even appear to accumulate in the gel, with enrichment factors typically on the order of 10. The results have consequences for the interpretation of DGT-data on metal fluxes from aquatic media containing humics and fulvics. PMID:20446728

van der Veeken, Pascal L R; Chakraborty, P; Leeuwen, Herman P van

2010-06-01

296

Dielectric properties of gel collected from shark electrosensors  

NASA Astrophysics Data System (ADS)

To investigate the physical mechanism of the electric sense, we present an initial characterization of the dielectric properties of the glycoprotein gel that fills the electrosensitive organs of marine elasmobranches (sharks, skates, and rays). To ascertain the properties of the gel, low-frequency impedance spectroscopy is used. The impedance data collected from a dialyzed sample show large values of static permittivity and a loss peak corresponding to a long relaxation time (about 1 ms). Impedance measurements of the native (nondialyzed) gel reliable to 0.1 Hz will be presented and compared to the dialyzed gel. Ramifications of the gel's dielectric properties for the electric sense will be explored.

Hughes, Mary E.; Brown, Brandon R.; Hutchison, John C.; Murray, Royce W.

2003-03-01

297

Characterization of fish acid proteases by substrate-gel electrophoresis  

Microsoft Academic Search

Several analytical techniques based upon the use of substrate-polyacrylamide gel electrophoresis were evaluated to achieve characterization of aspartate proteases in fish stomach. Since aspartate proteases of fish are more stable at high pH than mammalian pepsins, the most accurate technique for activity assessment is electrophoresis at neutral pH and revealing of such activity at low pH with hemoglobin as substrate.

Manuel Diaz-Lopez; Francisco J. Moyano-Lopez; F. Javier Alarcon-Lopez; Fernando L. Garcia-Carreno; M. Angeles; Navarrete del Toro

298

Ultrasensitive Fluorescence-Based Detection of Nascent Proteins in Gels  

Microsoft Academic Search

The most common method of analysis of proteins synthesized in a cell-free translation system (e.g., nascent proteins) involves the use of radioactive amino acids such as [35S]methionine or [14C]leucine. We report a sensitive, nonisotopic, fluorescence-based method for the detection of nascent proteins directly in polyacrylamide gels. A fluorescent reporter group is incorporated at the N-terminus of nascent proteins using an

Sadanand Gite; Sergey Mamaev; Jerzy Olejnik; Kenneth Rothschild

2000-01-01

299

Injectable gels of anionic collagen:rhamsan composites for plastic correction: preparation, characterization, and rheological properties.  

PubMed

The present article describes the preparation and characterization of anionic collagen gels obtained from porcine intestinal submucosa after 72 h of alkaline treatment and in the form of rhamsan composites to develop injectable biomaterials for plastic reconstruction. All materials were characterized by SDS/polyacrylamide gel electrophoresis, infrared spectroscopy, thermal stability, potentiometric titration, rheological properties, and fluidity tests. Biocompatibility was appraised after the injection of anionic collagen: rhamsan composites at 2.5% in 60 North Folk rabbits. Independently of processing, the collagen's secondary structure was preserved in all cases, and after 72 h of hydrolysis the collagen was characterized by a carboxyl group content of 346+/-9, which, at physiological pH, corresponds to an increase of 106+/-17 negative charges, in comparison to native collagen, due to the selective hydrolysis of asparagine and glutamine carboxyamide side chain. Rheological studies of composites at pH 7.4 in concentrations of 2, 4, and 6% (in proportions of 75:1 and 50:1) showed a viscoelastic behavior dependent on the frequency, which is independent of concentration and proportion. In both, the concentration of the storage modulus always predominated over the loss modulus (G'>G'' and delta<45 degrees ). The results from creep experiments confirmed this behavior and showed that anionic collagen:rhamsan composites at pH 7.4 in the proportion of 50:1 are less elastic and more susceptible to deformation in comparison to gels in the proportion of 75:1, independent of concentration. This was further confirmed by flow experiments, indicating that the necessary force for the extrusion of anionic collagen:rhamsan composites, in comparison to anionic collagen, was significantly smaller and with a smooth flow. Biocompatibility studies showed that the tissue reaction of anionic collagen:rhamsan composites at 2.5% in the proportion of 75:1 was compatible with the application of these gels in plastic reconstruction. These results suggest that the association of collagen with rhamsan may be a good alternative in the replacement of glutaraldehyde to stabilize the microfibril assembly of commercial collagen gel preparations. PMID:16037966

de Paula, Márcio; Goissis, Gilberto; Martins, Virgínia C A; da Silva Trindade, José Carlos

2005-11-01

300

Cationic polyacrylamides enhance rates of starch and cellulose saccharification.  

PubMed

Adding a cationic polyacrylamide (c-PAM) to either the amylase mediated hydrolysis of corn starch or the hydrolysis of wood fiber by cellulase can enhance the initial hydrolysis rates, although a rate decrease can occur under some conditions. Several c-PAMs can serve as catalysts and the same c-PAM can improve the efficiency of both amylase and cellulase. The initial amylase rate approximately doubles; the analogous cellulase hydrolysis rate increases by about 40%. c-PAMs increase the binding of enzyme to substrate. PMID:19547927

Reye, John T; Maxwell, Kendra; Rao, Swati; Lu, Jian; Banerjee, Sujit

2009-06-23

301

Preconditioning concepts in polyacrylamide flooding in high salinity reservoirs  

SciTech Connect

Because of its salt sensitivity polyacrylamide solutions, selected for polymer flooding for economic reasons have to be prepared in fresh water, and the highly saline reservoirs have to be preconditioned. The authors discuss two methods of preconditioning: a preflush with fresh water and use of a comparatively small slug of a less salt sensitive polymer. Results of laboratory work leading to the improved preconditioning concept with polymer are described. Case histories of two projects with both preconditioning processes are presented and discussed in detail.

Sohn, W.O. (Edeleanu Gasellschaft mbH (DE)); Volz, H.; Maitin, B. (Deutsche Texaco AG (DE))

1988-01-01

302

Optimization of the mineral content in polymeric gels: The effect of calcium to phosphate molar ratio  

Microsoft Academic Search

The influence of calcium to phosphate (Ca\\/P) molar ratio on the extent of mineralization in a model (poly)acrylamide gel was investigated under simulated physiological conditions. We hypothesized that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca\\/P molar ratio of 1.67. Phosphate ions were incorporated during the polymerization of the gel and mineralization was initiated by

Prasenjit Das; Ozan Akkus; Abdul-Majeed Azad

2005-01-01

303

Amphiphilic polymer–liposome interaction: a novel immobilization technique for liposome on gel surface  

Microsoft Academic Search

We developed a simple method for the immobilization of liposomes and biological membrane fragments to gel surface using an amphiphilic polymer, consisting of octadecylacrylamide and N,N-dimethylacrylamide with a molar ratio of 99:1. Calcein-entrapped egg phosphatidylcholine liposomes were successfully immobilized to the surface of polyacrylamide gel containing the polymer without significant loss of entrapped calcein. Different contents of the amphiphilic polymer

Masayuki Hara; Huiqing Yuan; Masao Miyake; Sadayo Iijima; Qing Yang; Jun Miyake

2000-01-01

304

Electric Field Enhanced Diffusion of Salicylic Acid through Polyacrylamide Hydrogels  

NASA Astrophysics Data System (ADS)

The release mechanisms and the diffusion coefficients of salicylic acid -loaded polyacrylamide hydrogels were investigated experimentally by using a modified Franz-diffusion cell at 37 ^oC to determine the effects of crosslinking ratio and electric field strength. A significant amount of salicylic acid is released within 48 hours from the hydrogels of various crosslinking ratios, with and without electric field. The release characteristic follows the Q vs. t^1/2 linear relationship. Diffusion coefficient initially increases with increasing electric field strength and reaches the maximum value at electric field strength of 0.1 V; beyond that it decreases with electric field strength and becomes saturated at electric field strength of 5 V. The diffusion coefficient increases at low electric field strength (less 0.1 V) as a result of the electrophoresis of the salicylic acid, the expansion of pore size, and the induced pathway in pigskin. For electric field strength higher than 0.1 V, the decrease in the diffusion coefficient is due to the reduction of the polyacrylamide pore size. The diffusion coefficient obeys the scaling behavior D/Do=(drug size/pore size)^m, with the scaling exponent m equal to 0.93 and 0.42 at electric fields of 0 and 0.1 V, respectively.

Niamlang, Sumonman; Sirivat, Anuvat

2008-03-01

305

Molecular design of modified polyacrylamide for the salt tolerance.  

PubMed

In our work, three kinds of functional monomers were selected to modify polyacrylamide (PAM) or partially hydrolyzed polyacrylamide (HPAM) by molecular dynamics simulation so as to achieve the stronger salt-tolerance of modified HM-HPAM. The radius of gyration (R (g)), the hydrodynamic radius (R (H)), the effective length (L (ef)) and the intrinsic viscosity ([?]) for modified PAM or HPAM were studied in aqueous solutions with different ionic strength at 298 K. The results showed that modified HM-HPAM has a stronger salt tolerance and the salt tolerance increases gradually from HM-HPAM1 to HM-HPAM3 because the monomers with different steric hindrance would reduce the curliness of molecular chains and, consequently, improve the salt tolerance. So, introducing the steric hindrance monomer into polymer will increase the salt tolerance of the polymer and it is indicated that the simulated results agree with the experimental results very well. Furthermore, the radial distribution function (RDF) has been used to investigate the effect of NaCl on the hydration of the -COO- groups of the HM-HPAM from microscopic view. PMID:22643970

Yao, Lin; Chen, Panke; Ding, Bin; Luo, Jianhui; Jiang, Bo; Zhou, Ge

2012-05-29

306

Multifunctional Biodegradable Polyacrylamide Nanocarriers for Cancer Theranostics - A "See and Treat" Strategy  

PubMed Central

We describe here the development of multifunctional nanocarriers, based on amine functionalized biodegradable polyacrylamide nanoparticles (NPs), for cancer theranostics, including active tumor targeting, fluorescence imaging and photodynamic therapy. The structural design involves adding primary amino groups and biodegradable crosslinkers during the NP polymerization, while incorporating photodynamic and fluorescent imaging agents into the NP matrix, and conjugating PEG and tumor-targeting ligands onto the surface of the NPs. The as-synthesized NPs are spherical, with an average diameter of 44 nm. An accelerated biodegradation study, using sodium hydroxide or porcine liver esterase, indicated a hydrogel polymer matrix chain collapse within several days. By using gel permeation chromatography, small molecules were detected, after the degradation. In vitro targeting studies on human breast cancer cells indicate that the targeted NPs can be transported efficiently into tumor cells. Incubating the multifunctional nanocarriers into cancer cells enabled strong fluorescence imaging. Irradiation of the photosensitizing drug, incorporated within the NPs, with light of a suitable wavelength, causes significant but selective damage to the impregnated tumor cells, but only inside the illuminated areas. Overall, the potential of polymeric-based NPs as biodegradable, multifunctional nanocarriers, for cancer theranostics, is demonstrated here.

Wang, Shouyan; Kim, Gwangseong; Lee, Yong-Eun Koo; Hah, Hoe Jin; Ethirajan, Manivannan; Pandey, Ravindra K.; Kopelman, Raoul

2012-01-01

307

Ratio of Moduli of Polyelectrolyte Gels in Water with and Without Salt.  

National Technical Information Service (NTIS)

The ratio of bulk modulus to shear modulus, K/G, of ionic polyacrylamide(PAAM) gels is studied as functions of degree of ionization and salt concentration. This ratio is directly related to the exponents characterizing the concentration dependence of bulk...

Y. Li C. Li Z. Hu

1994-01-01

308

Multilocus enzyme analysis in aerobic and anaerobic bacteria using gel electrophoresis–nitrocellulose blotting  

Microsoft Academic Search

An optimized multilocus enzyme electrophoresis method, which involves polyacrylamide–agarose gel electrophoresis followed by electrophoretic transfers on nitrocellulose sheets, was developed for the analysis of enzyme polymorphism in several aerobic and anaerobic bacterial species including Staphylococcus aureus, Streptococcus pneumoniae, S. agalactiae, Klebsiella pneumoniae and K. oxytoca, Clostridium bifermentans and C. sordellii, and Prevotella bivia. Serial electrophoretic transfers (during 5–15 min each)

Marie-Laure Combe; Jean-François Lemeland; Martine Pestel-Caron; Jean-Louis Pons

2000-01-01

309

Biologist's perspective on analytical imaging systems as applied to protein gel electrophoresis  

Microsoft Academic Search

High-resolution two-dimensional polyacrylamide gel electrophoresis entails the separation of proteins in the first dimension according to their charge and in the second dimension according to their relative mobility (RF). The technique is capable of simultaneously resolving thousands of polypeptides as a constellation pattern of spots. Ultimately, the level of success in the analysis of such protein patterns depends upon the

Wayne F. Patton

1995-01-01

310

Microsequence analysis of winged bean seed proteins electroblotted from two-dimensional gel  

Microsoft Academic Search

Electroblotting method employing a semidry blotting apparatus for the subsequent protein microsequence analysis (Hirano, 1987) was improved. This method is convenient and allows rapid and efficient transfer of the proteins from a polyacrylamide gel (1 mm thick) onto the Polybrene-coated glass-fiber sheet or polyvinylidene difluoride membrane filter in only 20 min. The electroblotted proteins could be sequenced directly with the

Hisashi Hirano

1989-01-01

311

Gradient gel electrophoretic separation of LDL and HDL subclasses on BioRad Mini Protean II and size phenotyping in healthy Macedonians  

Microsoft Academic Search

Background: Lipoprotein subclass determinations provide a more detailed reflection of lipoprotein metabolism and an accurate prediction for risk of cardiovascular disease. Gradient gel electrophoresis for lipoprotein separation on Pharmacia electrophoretic apparatus has been most commonly used for many years. Methods: In this paper, we describe a new method for separating LDL and HDL subclasses by nondenaturing polyacrylamide gradient (3–31%) gel

Sonja B Alabakovska; Bojana B Todorova; Danica D Labudovic; Katerina N Tosheska

2002-01-01

312

Measurements of Elastic Moduli of Silicone Gel Substrates with a Microfluidic Device  

PubMed Central

Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the device to gels with elastic moduli in a range from 0.4 to 300 kPa that are all prepared by mixing two components of a transparent commercial silicone Sylgard 184. The elastic modulus is measured by tracking beads on the gel surface under a wide-field fluorescence microscope without any other specialized equipment. The measurements have small and simple to estimate errors and their results are confirmed by conventional tensile tests. A master curve is obtained relating the mixing ratios of the two components of Sylgard 184 with the resulting elastic moduli of the gels. The rigidity of the silicone gels is less susceptible to effects from drying, swelling, and aging than polyacrylamide gels and can be easily coated with fluorescent tracer particles and with molecules promoting cellular adhesion. This work can lead to broader use of silicone gels in the cell biology laboratory and to improved repeatability and accuracy of cell traction force microscopy and rigidity sensing experiments.

Gutierrez, Edgar; Groisman, Alex

2011-01-01

313

Measurements of elastic moduli of silicone gel substrates with a microfluidic device.  

PubMed

Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the device to gels with elastic moduli in a range from 0.4 to 300 kPa that are all prepared by mixing two components of a transparent commercial silicone Sylgard 184. The elastic modulus is measured by tracking beads on the gel surface under a wide-field fluorescence microscope without any other specialized equipment. The measurements have small and simple to estimate errors and their results are confirmed by conventional tensile tests. A master curve is obtained relating the mixing ratios of the two components of Sylgard 184 with the resulting elastic moduli of the gels. The rigidity of the silicone gels is less susceptible to effects from drying, swelling, and aging than polyacrylamide gels and can be easily coated with fluorescent tracer particles and with molecules promoting cellular adhesion. This work can lead to broader use of silicone gels in the cell biology laboratory and to improved repeatability and accuracy of cell traction force microscopy and rigidity sensing experiments. PMID:21980487

Gutierrez, Edgar; Groisman, Alex

2011-09-30

314

Rare earth oxide-doped titania nanocomposites with enhanced photocatalytic activity towards the degradation of partially hydrolysis polyacrylamide  

NASA Astrophysics Data System (ADS)

Rare-earth oxide-doped titania nanocomposites (RE3+/TiO2, where RE = Eu3+, Pr3+, Gd3+, Nd3+, and Y3+) were prepared by a one-step sol-gel-solvothermal method. The products exhibited anatase phase structure, mesoporosity, and interesting surface compositions with three oxygen species and two titanium species. The products were used as the photocatalysts to degrade a partially hydrolysis polyacrylamide (HPAM) under UV-light irradiation, a very useful polymer in oil recovery. For comparison, Degussa P25 and as-prepared pure TiO2 were also tested under the same conditions. The enhanced photocatalytic activity was obtained on as-prepared Eu3+ (Gd3+, Pr3+)/TiO2 composites, and the reasons were explained. Finally, the degradation pathway of HPAM over the RE3+/TiO2 composite was put forward based on the intermediates produced during the photocatalysis procedure.

Li, Jinhuan; Yang, Xia; Yu, Xiaodan; Xu, Leilei; Kang, Wanli; Yan, Wenhua; Gao, Hongfeng; Liu, Zhonghe; Guo, Yihang

2009-01-01

315

Flocculation activity of novel ferric chloride–polyacrylamide (FeCl 3PAM) hybrid polymer  

Microsoft Academic Search

A ferric chloride–polyacrylamide inorganic–organic hybrid polymer has been synthesized using a ferric chloride\\/polyacrylamide ratio of 1:1 via free radical solution polymerization. A redox initiation system - (NH4)2S2O8 and NaHSO3 was used to initiate the polymerization at 50°C in aqueous medium. The ferric chloride–polyacrylamide hybrid polymer was characterized using Fourier transform infrared (FT-IR) spectrometer to determine their functional groups in the

Khai Ern Lee; Tjoon Tow Teng; Norhashimah Morad; Beng Teik Poh; Mohanapriya Mahalingam

2011-01-01

316

Equipment for dissolving polyacrylamide powder for obtaining an aqueous solution thereof for enhanced oil recovery  

SciTech Connect

Equipment for dissolving polyacrylamide powder to obtain an aqueous solution thereof for enhanced oil recovery comprises first and second powder storage tanks for storing polyacrylamide powder under nitrogen atmosphere; a gas conveyor unit for carrying the polyacrylamide powder from the first storage tank to the second storage tank by nitrogen gas flow; a constant powder supply unit for receiving the polyacrylamide powder from the second storage tank, metering the powder, and sending the metered powder to a powder dispersion unit for dispersing in water the polyacrylamide powder. A first liquid supply unit sends the dispersion or solution of polyacrylamide powder obtained from the powder dispersion unit to a dissolution tank for completing dissolution of the polyacrylamide; and a second liquid supply unit transfers the polyacrylamide solution from the dissolution tank to a solution storage tank for storing the polyacrylamide solution. A filtration unit is connected in the liquid supply line between the dissolution tank and the solution storage tank; and a nitrogen gas supply system maintains the interiors of these units filled with nitrogen gas at a pressure higher than atmospheric pressure.

Sekimoto, Y.; Okamoto, O.

1985-05-21

317

Testosterone Gel REMS  

Center for Drug Evaluation (CDER)

Text VersionPage 1. Initial REMS Approval: 02/2012 Testosterone Gel CIII Drug Class and Formulation: Testosterone Gel Products ... use of testosterone gel. II. ... More results from www.fda.gov/downloads/drugs/drugsafety

318

Polyacrylamide brush coatings preventing microbial adhesion to silicone rubber.  

PubMed

Silicone rubber is a frequently used biomaterial in biomedical devices and implants, yet highly prone to microbial adhesion and the development of a biomaterial-centered infection. Effective coating of silicone rubber to discourage microbial adhesion has thus far been impossible due to the hydrophobic character of its surface, surface deterioration upon treatment and instability of coatings under physiological conditions. Here we present a method to successfully grow polyacrylamide (PAAm) brushes from silicone rubber surfaces after removal of low molecular weight organic molecules (LMWOM), such as silane oligomers. PAAm brush coating did not cause any surface deterioration and discouraged microbial adhesion, even after 1-month exposure to physiological fluids. The method presented opens many new avenues for the use of silicone rubber as a biomaterial, without the risk of developing a biomaterial-centered infection. PMID:18356029

Fundeanu, Irina; van der Mei, Henny C; Schouten, Arend J; Busscher, Henk J

2008-02-15

319

Polyacrylamide based ICG nanocarriers for enhanced fluorescence and photoacoustic imaging  

NASA Astrophysics Data System (ADS)

Indocyanine green (ICG) is an FDA approved tricarbocyanine dye. This dye, with a strong absorbance in the near infrared (NIR) region, has been extensively used for fluorescence and photoacoustic imaging in vivo. ICG in its free form, however, has a few drawbacks that limit its in vivo applications, such as non-targetability, tendency to form aggregates which changes its optical properties, fast degradation, short plasma lifetime and reduced fluorescence at body temperature. In order to bypass these inherent drawbacks, we demonstrate a polyacrylamide based nanocarrier that was particularly designed to carry the negatively charged ICG molecules. These nanocarriers are biodegradable, biocompatible and can be specifically targeted to any cell or tissue. Using these nanocarriers we avoid all the problems associated with free ICG, such as degradation, aggregation and short plasma lifetime, and also enhance demonstrate its ability towards photoacoustics and fluorescence imaging.

Ray, Aniruddha; Yoon, Hyung Ki; Ryu, HeeJu; Koo Lee, Yong-Eun; Kim, Gwangseong; Wang, Xueding; Kopelman, Raoul

2013-02-01

320

Polyacrylamide polymer viscosity as a function of brine composition  

SciTech Connect

A computer model has been developed which predicts the viscosity of polymer and oil field brine mixtures. The polymers used were Amoco- Sweepaid 103 and Dow- Pusher 500 polyacrylamide polymers. All of the experiments were conducted at 1200 ppM polymer concentration. The computer input consists of the ionic strength of the brine in the mixture and the fraction of that ionic strength due to sodium ions. The computer program makes predictions of viscosity by referencing a family of viscosity curves for various mixtures of sodium chloride and calcium chloride in 1200 ppM polymer solutions. The model has been tested using 59 mixtures of brines and polymers. The ionic strength of the brine in the mixtures varied from 0.0018 to 0.025. The fraction of the brines' total ionic strength due to sodium ions varied from 0.22 to 0.49. The brines consisted predominantly of sodium, potassium, magnesium, calcium, chloride, bicarbonate and sulfate ions.

French, T.R.; Stacy, N.; Collins, A.G.

1981-05-01

321

Porous Polyacrylamide Monoliths in Hydrophilic Interaction Capillary Electrochromatography of Oligosaccharides  

PubMed Central

Capillary electrochromatography (CEC) of oligosaccharides in porous polyacrylamide monoliths has been explored. While it is possible to alter separation capacity for various compounds by copolymerization of suitable separation ligands in the polymerization backbone, “blank” acrylamide matrix is also capable of sufficient resolution of oligosaccharides in the hydrophilic interaction mode. The “blank” acrylamide network, formed with a more rigid crosslinker, provides maximum efficiency for separations (routinely up to 350,000 theoretical plates/m for fluorescently-labeled oligosaccharides). These columns yield a high spatial resolution of the branched glycan isomers and large column permeabilities. From the structural point of view, some voids are observable in the monoliths at the mesoporous range (mean pore radius ca. 35 nm, surface area of 74 m2/g), as measured by intrusion porosimetry in the dry state.

Guryca, Vilem; Mechref, Yehia; Palm, Anders K.; Michalek, Jiri; Pacakova, Vera; Novotny, Milos V.

2007-01-01

322

Experiencing Native American Culture.  

ERIC Educational Resources Information Center

Presents four experiential excercises based on Native American culture for use in education, communication training, and counseling. These excercises are intended as vehicles for personal growth and aids to learning about Native American culture. (RC)

Darou, Wes G.

1980-01-01

323

Native American Stereotypes  

NSDL National Science Digital Library

You have been asked to write an opinion paper on the topic of naming sports teams' mascots after Native Americans. Use the following websites to find information to support your opinions. Why Dont Native Americans Like Sports Teams With Indian Mascots? Sports, Mascots, and Native Americans Native American Mascots: Racial Slur or Cherished Tradition To see another perspective on this topic, read the book Who Will Tell My Brother by Marlene Carvell. ...

Bates, Albion M.

2007-03-20

324

Alaska Natives & the Land.  

ERIC Educational Resources Information Center

|Pursuant to the Native land claims within Alaska, this compilation of background data and interpretive materials relevant to a fair resolution of the Alaska Native problem seeks to record data and information on the Native peoples; the land and resources of Alaska and their uses by the people in the past and present; land ownership; and future…

Arnold, Robert D.; And Others

325

Purification of multisubunit membrane protein complexes: isolation of chloroplast FoF1-ATP synthase, CFo and CF1 by blue native electrophoresis.  

PubMed

The proton-ATP synthase of thylakoid membranes from chloroplasts (CFoF1) is composed of two parts with different structural and functional properties: the membrane-integral, proton-conducting complex CFo and the hydrophilic part, CF1 which catalyze the formation of adenosine-5'-triphosphate (ATP). To date it is difficult to isolate functional CFoF1 from thylakoids in high purity and yield. Blue native polyacrylamide gel electrophoresis (BN-PAGE) was therefore successfully employed to isolate CFoF1 in a one-step procedure from thylakoid membranes. Using a cathode buffer with low Coomassie Blue G-250 (CBG) concentration (0.002%), CFoF1 remains intact and can be obtained in high purity from solubilized, prepurified ATP synthase. Using BN-PAGE and a cathode buffer with 0.02% CBG, the ATP synthase bifurcates, and we were able to isolate both parts, CFo and CF1, separately. CFoF1, CFo, and CF1, respectively, were electroeluted nearly quantitatively electroeluted from the gel. BN-PAGE is a generally applicable method for the isolation and characterization of multisubunit membrane protein complexes in their native structure. However, the combination of neutral detergents and the negatively charged dye CBG seems to mimic properties of mild ionic detergents. This effect can lead to dissociation of labile subunits and subcomplexes, especially when delipidated membrane protein complexes are applied to BN-PAGE. By variation of the initial electrophoresis conditions, i.e., dye concentration in the cathode buffer, amount of lipid and detergent, BN-PAGE can be used for the isolation of either intact complexes or of subcomplexes. PMID:10364459

Neff, D; Dencher, N A

1999-06-16

326

Centrifugal methods and devices for rapid in-gel digestion of proteins.  

PubMed

Modern proteomic research frequently relies upon separation of proteins in a polyacrylamide gel matrix followed by in-gel enzymatic digestion and extraction of peptides for subsequent analysis by MS. In this work, we propose a novel semi-automated method of mechanical processing of gel bands by passing these bands through a specially designed centrifugal device termed a Gel Shredder prior to digestion and extraction of peptides. Such a device allows integrated washing, destaining and shredding of gel bands into uniform blocks of controlled size, approximately 150-300 microm, prior to the enzymatic digestion and extraction of peptides. Shredding into uniform blocks increases the surface area of the gel pieces and promotes improved gel rehydration, allowing improved diffusion of the proteolytic enzymes and solvent into the gel lattice. We demonstrate that the new method substantially reduces the time spent on tedious manual handling of gel bands, while minimizing the risk of sample contamination. The performance of the Gel Shredder has been compared with a conventional in-gel digestion protocol using several standard proteins and a complex proteomic sample in terms of relative quantitation by either MALDI-TOF/TOF or nanoLC-ESI IT-Fourier transformation ion cyclotron resonance MS. It is shown that significant time savings and improved peptide recovery can be obtained for many proteins using the Gel Shredder compared with the traditional in-gel digestion protocol. PMID:19309014

Lazarev, Alexander V; Rejtar, Tomas; Dai, Shujia; Karger, Barry L

2009-03-01

327

Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots  

DOEpatents

After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a dc power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. 8 figs.

Zhang, Jian-Shi; Giometti, C.S.; Tollaksen, S.L.

1987-09-04

328

Improved native affinity purification of RNA.  

PubMed

RNA biochemical or structural studies often require an RNA sample that is chemically pure, and most protocols for its in vitro production use denaturing polyacrylamide gel electrophoresis to achieve this. Unfortunately, many RNAs do not quantitatively refold into an active conformation after denaturation, creating significant problems for downstream characterization or use. In addition, this traditional purification method is not amenable to studies demanding high-throughput RNA production. Recently, we presented the first general method for producing almost any RNA sequence that employs an affinity tag that is removed during the purification process. Because technical difficulties prevented application of this method to many RNAs, we have developed an improved version that utilizes a different activatable ribozyme and affinity tag that are considerably more robust, rapid, and broadly applicable. PMID:17548432

Batey, Robert T; Kieft, Jeffrey S

2007-06-04

329

Purification of native myosin filaments from muscle.  

PubMed Central

Analysis of the structure and function of native thick (myosin-containing) filaments of muscle has been hampered in the past by the difficulty of obtaining a pure preparation. We have developed a simple method for purifying native myosin filaments from muscle filament suspensions. The method involves severing thin (actin-containing) filaments into short segments using a Ca(2+)-insensitive fragment of gelsolin, followed by differential centrifugation to purify the thick filaments. By gel electrophoresis, the purified thick filaments show myosin heavy and light chains together with nonmyosin thick filament components. Contamination with actin is below 3.5%. Electron microscopy demonstrates intact thick filaments, with helical cross-bridge order preserved, and essentially complete removal of thin filaments. The method has been developed for striated muscles but can also be used in a modified form to remove contaminating thin filaments from native smooth muscle myofibrils. Such preparations should be useful for thick filament structural and biochemical studies.

Hidalgo, C; Padron, R; Horowitz, R; Zhao, F Q; Craig, R

2001-01-01

330

Management for Postoperative Complications of Breast Augmentation by Injected Polyacrylamide Hydrogel  

Microsoft Academic Search

Polyacrylamide hydrogel, a new biomaterial, has been used for injected breast augmentation in China since 1997. A series of 30 patients with various complications after injected polyacrylamide hydrogel visited the author’s department. Most of these patients had undergone injection of both breasts. The average age of the patients was 27.6 years, and the time of consultation for the complications was

Qun Qiao; Xiancheng Wang; Jiaming Sun; Ru Zhao; Zhifei Liu; Yang Wang; Baodong Sun; Yinjun Yan; Keming Qi

2005-01-01

331

Stabilization and destabilization of hematite suspensions by neutral and anionic polyacrylamide  

Microsoft Academic Search

Polyacrylamide (PAM) and its hydrolysis products are widely used flocculants in water treatment. These relatively flexible polymers may also serve as models for certain natural organic matter rich in carboxyl groups in aquatic systems. We studied the aggregation kinetics of hematite in the presence of neutral and hydrolyzed polyacrylamide (HPAM) at low hydrolysis ratios (?=0.4–8.2%). Electrophoretic mobility measurements revealed that

J Zhang; C Huguenard; C Scarnecchia; R Menghetti; J Buffle

1999-01-01

332

Interaction Between the Hydrophobically Modified Polyacrylamide and HPAM-Flooding Produced Liquid  

Microsoft Academic Search

In order to utilize the produced liquid of hydrolyzed polyacrylamide (HPAM) flooding to enhance oil recovery, the interaction between hydrophobically modified polyacrylamide (HMPAM) and the produced liquid of HPAM flooding was investigated. The viscous characteristic of HMPAM in aqueous solution was investigated by Ubbelohde viscometer. The results show the intrinsic viscosity of HMPAM in aqueous solution is higher than that

Houjian Gong; Guiying Xu; Yebang Tan; Yajing Wang; Lushan Wang; Yuqin Tian; Hongjing Guo; Haibo Wang

2010-01-01

333

Automated and manual methods for the determination of polyacrylamide and other anionic polymers  

SciTech Connect

The concentration of polyacrylamides is determined by precipitation with Hyamine 1622 Reagent 1 and by measurement of the amount of light scattered by the resulting turbidity. The analysis can be automated as well as adapted for field trials. The effects of anionic surfactants, changes in polyacrylamide molecular weight, and salinity are discussed.

Allison, J.D.; Wimberly, J.W.; Ely, T.L.

1987-05-01

334

Rapid SDS-GEL capillary electrophoresis for the analysis of recombinant NADP +-dependent formate dehydrogenase during expression in Escherichia coli cells and its purification  

Microsoft Academic Search

The level of expression in Escherichia coli cells and different steps of purification of the recombinant NADP+-dependent formate dehydrogenase (EC 1.2.1.2, FDH) from bacterium Pseudomonas sp.101 was analyzed by rapid SDS-Gel capillary electrophoresis (SDS-Gel CE) and compared with SDS polyacrylamide gel electrophoresis (SDS PAGE). First standard proteins were separated in the short capillary and the calibration curve generated, then fractions

V Klyushnichenko; V Tishkov; M.-R Kula

1997-01-01

335

A Pneumatic Device for Rapid Loading of DNA Sequencing Gels  

PubMed Central

This work describes the design and construction of a device that facilitates the loading of DNA samples onto polyacrylamide gels for detection in the Perkin Elmer/Applied Biosystems (PE/ABI) 373 and 377 DNA sequencing instruments. The device is mounted onto the existing gel cassettes and makes the process of loading high-density gels less cumbersome while the associated time and errors are reduced. The principle of operation includes the simultaneous transfer of the entire batch of samples, in which a spring-loaded air cylinder generates positive pressure and flexible silica capillaries transfer the samples. A retractable capillary array carrier allows the delivery ends of the capillaries to be held up clear of the gel during loader attachment on the gel plates, while enabling their insertion in the gel wells once the device is securely mounted. Gel-loading devices capable of simultaneously transferring 72 samples onto the PE/ABI 373 and 377 are currently being used in our production sequencing groups while a 96-sample transfer prototype undergoes testing.

Panussis, Dimitrios A.; Cook, Mark W.; Rifkin, Lisa L.; Snider, Jacqueline E.; Strong, Joseph T.; McGrane, Rebecca M.; Wilson, Richard K.; Mardis, Elaine R.

1998-01-01

336

Two-dimensional gel electrophoresis: vertical isoelectric focusing.  

PubMed

Two-dimensional gel electrophoresis (2-DE) is one of the most powerful tools for separating proteins based on their size and charge. 2-DE is very useful to separate two proteins with identical molecular weights but different charges, which cannot be achieved with just sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Here, a simpler and easier version of 2-DE is presented which is also faster than all the currently available techniques. In this modified version of 2-DE, isoelectric focusing is carried out in the first dimension using a vertical SDS-PAGE apparatus. Following the first-dimensional IEF, each individual lane is excised from the IEF gel and, after a 90° rotation, is inserted into a second-dimensional SDS-PAGE, which can be stained with Coomassie Brilliant Blue for protein analysis or immunoblotted for further analysis. This version of IEF can be run in less than 2 h compared to the overnight run required by O'Farrell's method. Difficult tube gel casting and gel extrusion as well as tube gel distortion are eliminated in our method. This method is simpler, faster, and inexpensive. Both dimensions can be done on the same SDS-PAGE apparatus, and up to ten samples can be run simultaneously using one gel. PMID:22585490

Dorri, Yaser

2012-01-01

337

Calibration of laser tomography as a new optical diagnostic tool applied to dosimetric polymer gels  

NASA Astrophysics Data System (ADS)

Numerous medical applications, as radiotherapy for example, require accurate and reproducible three-dimensional dose measurements with high spatial resolution. A solution of great interest and which has been exploited for many years is the use of dosimetric gels based on different physico-chemical principles, as Fricke’s gels or polymer gels. Fricke’s gels take advantage of the oxidation of ferrous ions in ferric while polymer gels are the result of the synthesis of polyacrylamide hydrogel from monomer and cross-linking agent. Fricke’s gels have particular limitations not encountered with polymer gel dosimeters: the time delay between irradiation and measurement must be reduced in order to limit the diffusion of ferric ions which may remove the spatial dose information. That’s why, during the past decade, many compositions of polymer gels have been studied (PAG, MAGIC, …), elaborated and even commercialized (BANG gels). However the gel composition remains of great interest regarding its physical properties. In this work, the authors propose a new optical diagnostic tool more flexible and less expensive in comparison with existing techniques like magnetic resonance imaging (MRI) and Optical-CT. This technique is based on light scattering behaviour occurring in an irradiated polymer gel (note that light scattering in Fricke’s gels is very feeble, the latter being essentially absorbant).

Alwan, R.; Guermeur, F.; Bailly, Y.; Simonin, L.; Svoboda, J.; Makovicka, L.; Martin, E.

2008-03-01

338

Purification of ADP-ribosylated nuclear proteins by covalent chromatography on dihydroxyboryl polyacrylamide beads and their characterization.  

PubMed Central

Nuclear proteins modified by mono or poly ADP-ribosylation were selectively isolated and purified by covalent chromatography on a dihydroxyboryl polyacrylamide bead column that specifically interacts with cis-diol-containing compounds. From rat liver nuclei that had been incubated with NAD+, histones and some nonhistone proteins were extracted with 0.25 M HCl. Approximately 60% of the ADP-ribose incorporated into 20% trichloroacetic acid-precipitable material was recovered in this extract. The ADP-ribosylated material was then isolated from the extract by covalent chromatography on a borate gel column and further purified by carboxymethylcellulose column chromatography. As judged by electrophoretic mobilities in various gel systems and by amino acid compositions, approximately 50% of the ADP-ribose recovered in the carboxymethylcellulose fractions was associated with several nonhistone proteins with molecular weights of 2-6 x 10(4), while 35% aand 15% were associated with histones H2B and H1, respectively. Since the average chain length of the polymer bound to any of these proteins was less than two ADP-ribos-l units, the percentage distribution reflects the number of ADP-ribosylated sites rather than the chain length. Images

Okayama, H; Ueda, K; Hayaishi, O

1978-01-01

339

Polyacrylamide hydrogel injection for breast augmentation: Another injectable failure  

PubMed Central

Summary Background Increasing complications of polyacrylamide hydrogel (PAAG) augmentation mammoplasty, such as chronic persistent infection, have recently caught the attention of both the medical field and the general public. Material/Methods A total of 96 patients with severe chronic infection following PAAG augmentation mammoplasty were treated in the present study including 63 cases with infection confined to the breast and 33 with systemic infection. Endoscopy and surgery were performed to completely remove the materials and clear the infected tissues followed by drug-irrigation and vacuum-assisted closure for several days. Results In patients with severe infection there were large amounts of PAAG, fibers and infiltration of numerous neutrophils and macrophages. The infection-inducing materials were extensively dispersed in the mammary and subcutaneous tissues, pectoral fascia and intermuscular space. In addition, there was scattered distribution of PAAG materials in the armpit, chest wall and abdominal wall, which were mixed with necrotic tissues and surrounded by lymphocytes, giant cells, macrophages and other inflammatory cells, forming chronic granulomatous and fibrous lesions. Infection was controlled following surgical intervention. No residual infectious foci or recurrent infections were noted among these patients. Although the severe infection did not result in mastectomy, patients had breast atrophy and various degrees of deformation. Conclusions Chronic infection following PAAG augmentation mammaplasty usually causes systemic infection and other devastating adverse reactions. This study confirms PAAG augmentation mammaplasty is another failed attempt. More attention should be paid to the injection of large doses of liquid filler.

Wang, Zhenxiang; Li, Shirong; Wang, Lingli; Zhang, Shu; Jiang, Yan; Chen, Jinping; Luo, Donglin

2012-01-01

340

Encapsulation efficiency and controlled release characteristics of crosslinked polyacrylamide particles.  

PubMed

Polyacrylamide (pAAm) particles crosslinked with N,N-methylenebis-acrylamide/ethylene glycol dimethacrylate (NNMBA/EGDMA) have been prepared in water-methanol medium by the dispersion polymerization using poly(vinyl pyrrolidone), PVP as a steric stabilizer. 5-fluorouracil an anticancer drug, has been loaded in situ into the crosslinked pAAm particles. Plain as well as drug loaded microparticles have been characterized by differential scanning calorimetry (DSC) and X-ray diffraction studies (XRD) and scanning electron microscopy (SEM). DSC and XRD studies have indicated a molecular level dispersion of the drug in pAAm particles during in situ loading and SEM pictures have shown the formation of spherical and oval-shaped particles. In vitro release of 5-fluorouracil from the crosslinked pAAm particles has been carried out in 7.4 pH buffer medium. Both encapsulation efficiency and release patterns are found to depend on the nature of the crosslinking agent, amount of crosslinking agent used and the amount of drug loaded. In vitro release studies indicated the controlled release of 5-fluorouracil up to 12 h. PMID:16766148

Sairam, Malladi; Babu, V Ramesh; Vijaya, Boya; Naidu, Kumar; Aminabhavi, Tejraj M

2006-08-31

341

Acrylamide monomer leaching from polyacrylamide-treated irrigation furrows.  

PubMed

Water-soluble anionic polyacrylamide (WSPAM), which is used to reduce erosion in furrow irrigated fields and other agriculture applications, contains less than 0.05% acrylamide monomer (AMD). Acrylamide monomer, a potent neurotoxicant and suspected carcinogen, is readily dissolved and transported in flowing water. The study quantified AMD leaching losses from a WSPAM-treated corn (Zea mays L.) field using continuous extraction-walled percolation samplers buried at 1.2 m depth. The samplers were placed 30 and 150 m from the inflow source along a 180-m-long corn field. The field was furrow irrigated using WSPAM at the rate of 10 mg L(-1) during furrow advance. Percolation water and furrow inflows were monitored for AMD during and after three furrow irrigations. The samples were analyzed for AMD using a gas chromatograph equipped with an electron-capture detector. Furrow inflows contained an average AMD concentration of 5.5 microg L(-1). The AMD in percolation water samples never exceeded the minimum detection limit and the de facto potable water standard of 0.5 microg L(-1). The risk that ground water beneath these WSPAM-treated furrow irrigated soils will be contaminated with AMD appears minimal. PMID:18948483

Lentz, R D; Andrawes, F F; Barvenik, F W; Koehn, A C

2008-10-23

342

Effect of cationic polyacrylamides on the interactions between cellulose fibers.  

PubMed

The interaction between cellulose fibers in the presence of cationic polyacrylamide (CPAM) was analyzed by rheology as a function of polyelectrolyte concentration, charge density, and molecular weight. CPAM was found to strongly influence the yield stress of cellulose suspensions; low doses of CPAM increased the yield stress, but at higher concentrations the yield stress declined. The charge density of the CPAM was the most significant factor in how yield stress responded to CPAM concentration; this effect was able to be normalized to a master curve by considering only the charged fraction of the polymer. The molecular weight of CPAM samples had some effect at high concentrations, but for lower CPAM doses the yield stress was independent of molecular weight over the range studied. The data suggest that CPAM modifies the interaction between cellulose surfaces via several mechanisms, with electrostatic interactions in the form of charge neutralization and charged patch formation dominating; polymer bridging and steric repulsion also influence the overall balance of forces between interacting cellulose fibers. PMID:22316050

Mosse, Wade K J; Boger, David V; Simon, George P; Garnier, Gil

2012-02-08

343

Controlling water in producing operations. Part 5. Using polyacrylamide polymers  

SciTech Connect

If used correctly, dilute polyacrylamide polymers are ideal water control materials since they may be injected without reducing oil or gas production, but will restrict water production. There is no need to detect the water production source or to isolate any zones (except in injection wells). Polymers are simply dissolved in water at the surface and injected into wells. They are a relatively low-cost treatment, since they are used at low concentrations (ca 2000 to 3000 ppm) and there is minimal well preparation. Field results have varied from manifold increases of oil production and nearly complete water shut-off to just the opposite. It is important to know these polymers characteristics, where they may be successful or unsuccessful, and how they should be used. Regardless of how they work (and 3 theories are given), polymers are useful for blocking water in producing wells and for plugging thief zones in injection wells. There are several generic types, each with its preferred application. In addition, service companies have developed new polymers especially for the oil field.

Sparlin, D.D.; Hagen, R.W. Jr.

1984-07-01

344

Detection of human butyrylcholinesterase-nerve gas adducts by liquid chromatography–mass spectrometric analysis after in gel chymotryptic digestion  

Microsoft Academic Search

To verify the exposure to nerve gas, a method for detecting human butyrylcholinesterase (BuChE)-nerve gas adduct was developed using LC–electrospray mass spectrometry (ESI-MS). Purified human serum BuChE was incubated with sarin, soman or VX, and the adduct was purified by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and digested in gel by treatment with chymotrypsin. The resulting peptide mixture was subjected

Kouichiro Tsuge; Yasuo Seto

2006-01-01

345

Native American Powerpoint Project  

NSDL National Science Digital Library

For this project students will research a Native American group that played an influential role in Alabama history. The students will then create a powerpoint describing the primary aspects of that group's heritage. Directions: 1. Choose any one of the Native American tribes we have been learning about in class. 2. Visit the following sites to learn more about the tribe that you have chosen: 1) Access Geneology 2) Native Languages ...

Albright, Miss

2009-07-09

346

Biologic and biochemic properties of recombinant platelet factor 4 demonstrate identity with the native protein.  

PubMed

Platelet factor 4 (PF4) is a 70 amino acid protein released from the alpha-granules of platelets after activation. The exact biologic function of this protein is unknown. We have constructed an expression vector for recombinant PF4 (rPF4) in the T7-based promoter vector pT7-7 to better study the relationship between PF4 structure and function. The protein was expressed in Escherichia coli and purified to homogeneity by heparin-agarose affinity chromatography and reverse-phase high-performance liquid chromatography. Purity of protein was confirmed by immunoblot analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which resulted in a single component with a molecular weight of 8,000 daltons. The amino acid composition and sequence of the N-terminal 20 residues showed that rPF4 is identical to PF4 prepared from human platelets (hPF4), except for an N-terminal initiating methionine residue. Immunoblots revealed that rPF4 and hPF4 bound polyclonal anti-hPF4 equally well, while chemotaxis experiments demonstrated similar potencies as neutrophil attractants. Dose-dependent neutrophil chemotactic responses and competitive studies with polyclonal anti-hPF4 antiserum further demonstrate similar chemotactic properties of the two PF4 species. In conclusion, our data show that this recombinant protein and the native protein appears to have similar immunologic, heparin-binding, and chemotactic properties. The chemotactic properties of hPF4 appear to be entirely intrinsic to the protein and not due, in part, to any contaminating protein. Furthermore, our expression vector should prove useful for the construction of recombinant forms of PF4 to investigate structure/function relationships of this biologically important protein. PMID:2178704

Park, K S; Rifat, S; Eck, H; Adachi, K; Surrey, S; Poncz, M

1990-03-15

347

Gel Filtration of Native and Modified Pig Serum Lipoproteins.  

National Technical Information Service (NTIS)

Total lipoproteins were isolated from pig blood serum and further separated into individual classes of very low-density (VLDL), low-density (LDL) and high-density (HDL) lipoproteins by preparative centrifugation in NaBr solutions. The same classes were ob...

M. Kalab W. G. Martin

1968-01-01

348

A gel-free approach in vascular smooth muscle cell proteome: perspectives for a better insight into activation  

Microsoft Academic Search

BACKGROUND: The use of chromatography coupled with mass spectrometry (MS) analysis is a powerful approach to identify proteins, owing to its capacity to fractionate molecules according to different chemical features. The first protein expression map of vascular smooth muscle cells (VSMC) was published in 2001 and since then other papers have been produced. The most detailed two-dimensional polyacrylamide gel electrophoresis

Silvia Rocchiccioli; Lorenzo Citti; Claudia Boccardi; Nadia Ucciferri; Lorena Tedeschi; Caterina Lande; Maria Giovanna Trivella; Antonella Cecchettini

2010-01-01

349

Human low density lipoprotein subfractions separated by gradient gel electrophoresis: composition, distribution, and alterations induced by cholesteryl ester transfer protein  

Microsoft Academic Search

Low density lipoprotein (LDL) subfractions were studied in sera from 208 normolipidemic, 22 hypercholester- olemic, and 33 hypertriglyceridemic subjects. Whole serum without preliminary ultracentrifugation was submitted to elec- trophoresis in a nondenaturing polyacrylamide gel. Three main LDL patterns were observed in normolipidemic sera: type 1, characterized by the presence of only one major band; type 2, characterized by the presence

Philippe Gambert; Catherine Bouzerand-Gambert; Anne Athias; Michel Farnier; Christian Lallemant

350

How deeply cells feel: methods for thin gels  

NASA Astrophysics Data System (ADS)

Tissue cells lack the ability to see or hear but have evolved mechanisms to feel into their surroundings and sense a collective stiffness. A cell can even sense the effective stiffness of rigid objects that are not in direct cellular contact—like the proverbial princess who feels a pea placed beneath soft mattresses. How deeply a cell feels into a matrix can be measured by assessing cell responses on a controlled series of thin and elastic gels that are affixed to a rigid substrate. Gel elasticity E is readily varied with polymer concentrations of now-standard polyacrylamide hydrogels, but to eliminate wrinkling and detachment of thin gels from an underlying glass coverslip, vinyl groups are bonded to the glass before polymerization. Gel thickness is nominally specified using micron-scale beads that act as spacers, but gels swell after polymerization as measured by z-section, confocal microscopy of fluorescent gels. Atomic force microscopy is used to measure E at gel surfaces, employing stresses and strains that are typically generated by cells and yielding values for E that span a broad range of tissue microenvironments. To illustrate cell sensitivities to a series of thin-to-thick gels, the adhesive spreading of mesenchymal stem cells was measured on gel mimics of a very soft tissue (e.g. brain, E ~ 1 kPa). Initial results show that cells increasingly respond to the rigidity of an underlying 'hidden' surface starting at about 10-20 µm gel thickness with a characteristic tactile length of less than about 5 µm.

Buxboim, Amnon; Rajagopal, Karthikan; Brown, Andre'E. X.; Discher, Dennis E.

2010-05-01

351

How deeply cells feel: methods for thin gels  

PubMed Central

Tissue cells lack the ability to see or hear but have evolved mechanisms to feel into their surroundings and sense a collective stiffness. A cell can even sense the effective stiffness of rigid objects that are not in direct cellular contact – like the proverbial princess who feels a pea placed beneath soft mattresses. How deeply a cell feels into a matrix can be measured by assessing cell responses on a controlled series of thin and elastic gels that are affixed to a rigid substrate. Gel elasticity E is readily varied with polymer concentrations of now-standard polyacrylamide hydrogels, but to eliminate wrinkling and detachment of thin gels from an underlying glass coverslip, vinyl groups are bonded to the glass before polymerization. Gel thickness is nominally specified using micron-scale beads that act as spacers, but gels swell after polymerization as measured by z-section, confocal microscopy of fluorescent gels. Atomic force microscopy (AFM) is used to measure E at gel surfaces, employing stresses and strains that are typically generated by cells and yielding values for E that span a broad range of tissue microenvironments. To illustrate cell sensitivities to a series of thin-to-thick gels, the adhesive spreading of mesenchymal stem cells was measured on gel mimics of a very soft tissue (eg. brain, E ~ 1 kPa). Initial results show that cells increasingly respond to the rigidity of an underlying ‘hidden’ surface starting at about 10–20 µm gel thickness with a characteristic tactile length of less than about 5 µm.

Buxboim, Amnon; Rajagopal, Karthikan; Brown, Andre' E.X.; Discher, Dennis E.

2010-01-01

352

Building Native Nations through Native Student's Commitment to Their Communities  

ERIC Educational Resources Information Center

One aspect of building Native nations entails motivating American Indian/Alaska Native youth to become committed to their communities so as to sustain and move forward with the goals of American Indian/Alaska Native nations. This study determined the impact of one Native American Studies department on its Native students' life goals. Through its…

Lee, Tiffany S.

2009-01-01

353

Probing structure-antifouling activity relationships of polyacrylamides and polyacrylates.  

PubMed

We have synthesized two different polyacrylamide polymers with amide groups (polySBAA and polyHEAA) and two corresponding polyacrylate polymers without amide groups (polySBMA and polyHEA), with particular attention to the evaluation of the effect of amide group on the hydration and antifouling ability of these systems using both computational and experimental approaches. The influence of polymer architectures of brushes, hydrogels, and nanogels, prepared by different polymerization methods, on antifouling performance is also studied. SPR and ELISA data reveal that all polymers exhibit excellent antifouling ability to repel proteins from undiluted human blood serum/plasma, and such antifouling ability can be further enhanced by presenting amide groups in polySBAA and polyHEAA as compared to polySBMA and polyHEA. The antifouling performance is positively correlated with the hydration properties. Simulations confirm that four polymers indeed have different hydration characteristics, while all presenting a strong hydration overall. Integration of amide group with pendant hydroxyl or sulfobetaine group in polymer backbones is found to increase their surface hydration of polymer chains and thus to improve their antifouling ability. Importantly, we present a proof-of-concept experiment to synthesize polySBAA nanogels, which show a switchable property between antifouling and pH-responsive functions driven by acid-base conditions, while still maintaining high stability in undiluted fetal bovine serum and minimal toxicity to cultured cells. This work provides important structural insights into how very subtle structural changes in polymers can yield great improvement in biological activity, specifically the inclusion of amide group in polymer backbone/sidechain enables to obtain antifouling materials with better performance for biomedical applications. PMID:23562049

Zhao, Chao; Zhao, Jun; Li, Xiaosi; Wu, Jiang; Chen, Shenfu; Chen, Qiang; Wang, Qiuming; Gong, Xiong; Li, Lingyan; Zheng, Jie

2013-04-02

354

Check dam and polyacrylamide performance under simulated stormwater runoff.  

PubMed

High levels of turbidity and fine suspended sediments are often found in stormwater discharges from construction sites even when best management practices (BMPs) for sediment control are in place. This study evaluated turbidity reduction by three check dam types: 1) rock check dam representing a standard BMP, 2) excelsior wattle representing a fiber check dam (FCD), and 3) rock check dam wrapped with excelsior erosion control blanket (rock + excelsior ECB) representing an alternative FCD. Three check dams (all same type) were installed in a lined, 24-m ditch on a 5-7% slope and three consecutive simulated stormwater flows were run in the ditch. Additional tests were performed by adding granular polyacrylamide (PAM) on the check dams in the same manner using two sediment sources differing in clay content. Without PAM treatment, significantly higher effluent turbidity (>900 nephelometric turbidity units (NTU)) exited the ditch with rock check dams than with excelsior wattles or rock + excelsior ECBs (<440 NTU). The extent of sediment deposition between the check dam types was in the order of excelsior wattle > rock + excelsior ECB > rock check dam, indicating better water pooling behind the wattle. The PAM treatment reduced turbidity substantially (>75% relative to no PAM treatment) for all check dam types and it was very effective in excelsior wattles (<57 NTU) and rock + excelsior ECBs (<90 NTU) even during the third storm event. This study demonstrates that the passive treatment of runoff with PAM on FCDs (or rock + excelsior ECB) in construction site ditches can be very effective for sediment retention and turbidity reduction. PMID:24036092

Kang, Jihoon; McCaleb, Melanie M; McLaughlin, Richard A

2013-09-11

355

Rheology and microstructure of heat-induced egg yolk gels  

Microsoft Academic Search

The evolution of native egg yolk undergoing a thermal-induced sol-gel transition was studied by using temperature controlled small amplitude oscillatory shear measurements. The critical gel point was determined according to Winter’s criterion: 1) from the measurements of storage and loss moduli as a function of heating time at different frequencies, and 2) from the exponents of the power law mechanical

Felipe Cordobés; Pedro Partal; Antonio Guerrero

2004-01-01

356

Running an Agarose Gel  

NSDL National Science Digital Library

This video adapted from the University of Leicester provides step-by-step instructions for loading samples into an agarose gel and then running the gel to separate DNA molecules according to their size.

Foundation, Wgbh E.

2011-11-07

357

Native American Addiction  

Microsoft Academic Search

Laurence Armand French has provided a review of the origin of Native American alcohol problems and the historical and contemporary responses to such problems. This essay summarizes and discusses seven key points made by French and expands his discussion of the sources and solutions to Native alcohol problems.

William L. White

2004-01-01

358

Listen to the Natives  

ERIC Educational Resources Information Center

|"Digital natives" refer to today's students because they are native speakers of technology, fluent in the digital language of computers, video games, and the Internet. Those who were not born into the digital world are referred to as digital immigrants. Educators, considered digital immigrants, have slid into the 21st century--and into the…

Prensky, Marc

2006-01-01

359

Native American Health  

Microsoft Academic Search

Health disparities between Native Americans and the general population of the United States are a major health concern. Traditional healing and culturally competent health care offer much promise in raising the health status of Native Americans. Traditional healing, although uniquely practiced by each indigenous culture, is generally a system of medicine based on the inseparability of mind, body, and spirit.

Danielle Carlock

2006-01-01

360

Traditional Native Poetry.  

ERIC Educational Resources Information Center

|While Native myths and legends were educational tools to transmit tribal beliefs and history, traditional American Indian poetry served a ritualistic function in everyday life. Few traditional Native songs, which all poems were, survive; only Mayan and Aztec poems were written, and most of these were burned by a Spanish bishop. In addition, many…

Grant, Agnes

1985-01-01

361

Federal Politics and Native Concerns. Native Viewpoints.  

ERIC Educational Resources Information Center

|Addresses some of the frustration felt by Canada's indigenous Indian population regarding the lack of attention afforded them in recent federal elections. Discusses Indian reaction to the Canadian Government's White Paper on Aboriginal peoples. Canadian natives felt this document actually represented a step backward in their struggle for…

Steinhauer, Noella

1997-01-01

362

REACTIVE EXTRUSION OF STARCH-POLYACRYLAMIDE GRAFT COPOLYMERS USING VARIOUS STARCHES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Graft copolymers of polyacrylamide and various substrates were prepared by reactive extrusion in a twin screw extruder using ammonium persulfate as initiator. Substrates included unmodified starches (corn, waxy maize, wheat, and potato), cationic starches, dextrin, dextran, and polyvinyl alcohol (P...

363

Polyacrylamide\\/Potassium-Chloride Mud for Drilling Water-Sensitive Shales  

Microsoft Academic Search

A shale-protective, water-base drilling fluid containing a high molecular-weight, partially hydrolyzed polyacrylamide and potassium chloride has been used in many wells around the world. A laboratory test for evaluating the ability of water-base muds to protect stressed shales under dynamic conditions was used in the initial development of the system. Field application of the polyacrylamide\\/potassium-chloride mud has been successful in

R. K. Clark; R. F. Scheuerman; H. Rath

1976-01-01

364

Physiological Response of Daphnia magna to Linear Anionic Polyacrylamide: Ecological Implications for Receiving Waters  

Microsoft Academic Search

Linear anionic polyacrylamide (LA-PAM) is being considered as a soil amendment to reduce seepage and infiltration in unlined\\u000a earthen canals. While polyacrylamides have been extensively used for potable water treatment, dewatering sewage sludge, coal\\u000a and mine processing, paper manufacturing, and agriculture, little is known about its ecological impact to aquatic ecosystems.\\u000a Acute toxicity (LC50, 24 and 48 h) and chronic exposure

Kumud Acharya; Candi Schulman; Michael H. Young

2010-01-01

365

Synthesis and aqueous solution properties of a novel non-ionic, amphiphilic comb-type polyacrylamide  

Microsoft Academic Search

Nowadays comb-type polyacrylamides are deemed to be the most promising oil-displacing agent in the field of enhanced oil recovery (EOR). We describe the synthesis of a non-ionic, amphiphilic macromer (OPAE) with acrylic acid (AA) and t-octylphenoxypolyoxyehylene (OP) by an esterification reaction. The macromer was then copolymerized with acrylamide (AM) under a free radical initiator system and a comb-type modified polyacrylamide

Yuntao Xu; Pin Gao; Mingzhu Yang; Guangsu Huang; Bingjie Wang

2011-01-01

366

Synthesis and Aqueous Solution Properties of a Novel NonIonic, Amphiphilic Comb-Type Polyacrylamide  

Microsoft Academic Search

Nowadays comb-type polyacrylamides are deemed to be the most promising oil-displacing agent in the field of enhanced oil recovery (EOR). We describe the synthesis of a nonionic, amphiphilic macromer (OPAE) with acrylic acid (AA) and t-octylphenoxypolyoxyehylene (OP) by an esterification reaction. The macromer was then copolymerized with acrylamide (AM) under a free radical initiator system and a comb-type modified polyacrylamide

Yuntao Xu; Pin Gao; Mingzhu Yang; Guangsu Huang; Bingjie Wang

2011-01-01

367

Solids and nutrient removal from flushed swine manure using polyacrylamides  

SciTech Connect

Most of the organic nutrients and reduced carbon (C) materials in liquid swine manure are contained in fine suspended particles that are not separated by available mechanical separators. Treatment with polyacrylamide (PAM) polymers prior to mechanical removal or gravity settling has the potential for enhancing solids-liquid separation, thus concentrating nitrogen (N), phosphorus (P), and organic C. In this work, the authors determined PAM charge and density characteristics most desirable for swine wastewater applications and established the optimum chemical requirement. Treatments were applied to flushed manure from two swine operations in North Carolina. Cationic PAMs significantly increased solids separation while performance of neutral and anionic types was not different from a control. Cationic PAMs with moderate-charge density (20%) were more effective than polymers with higher charge density. Flocs were large and effectively retained with a 1-mm screen. Optimum PAM rate varied with the amount of total suspended solids (TSS) in the liquid manure; 26 and 79 mg PAM/L for samples containing 1.5 and 4.1 g TSS/L, respectively. Corresponding TSS removal efficiencies were 90 to 94%. In contrast, screening without PAM treatment captured only 5 to 14% of the suspended solids. Polymer usage rate was consistent and averaged 2.0{degree} based on weight of dry solids produced. Volatile suspended solids (VSS) were highly correlated with TSS and comprised 79.5% of TSS. Chemical oxygen demand (COD) and organic nutrient concentrations in the effluent were also significantly decreased by PAM treatment. The decrease of COD concentration, an important consideration for odor control, was linearly related with removal of suspended solids, at a rate of 2.0 g COD/g TSS and 2.6 g COD/g VSS. Removal efficiency of organic N and P followed approximately a 1:1 relationship with removal efficiency of TSS. Chemical cost to capture 90% of the suspended solids was estimated to be $0.026 per hog per day ($2.79 per finished hog). Results obtained indicate that PAM treatment is very effective for removal of manure solids, COD, and organic nutrients from flushed swine effluents. The technology provides an attractive alternative to existing liquid manure handling methods for conserving nutrients and avoiding excessive nutrient application in areas where swine production is concentrated.

Vanotti, M.B.; Hunt, P.G.

1999-12-01

368

Inhibiting Your Native Language  

Microsoft Academic Search

ABSTRACT—After immersion in a foreign language, speakers,often have difficulty retrieving native-language words—a,phenomenon,known,as first-language attrition. We propose,that first-language attrition arises in part from thesuppression,of native-language phonologyduring second-language use, and thus is a case of phonological retrieval-induced forgetting. In two experiments, we in- vestigated,this hypothesis,by,having,native,English speakers,name,visual objects in a language,they were learning,(Spanish). Repeatedly,naming,the objects in Spanish reduced,the accessibility of the corresponding English

Benjamin J. Levy; Nathan D. Mcveigh; Alejandra Marful; Michael C. Anderson

369

Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots  

DOEpatents

After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a DC power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. A high percentage extraction of proteins is achieved. The extracted proteins can be removed and subjected to partial digestion by trypsin or the like, followed by two-dimensional electrophoresis, resulting in a gel slab having a pattern of peptide gel spots which can be cored out and subjected to electrophoretic extraction to extract individual peptides.

Zhang, Jian-Shi (Shanghai, CN); Giometti, Carol S. (Glenview, IL); Tollaksen, Sandra L. (Montgomery, IL)

1989-01-01

370

Electrophoretic Analysis of Ribosomal and Viral Ribonucleic Acids with a Simple Technique for Slicing Low-Concentration Polyacrylamide Gels.  

National Technical Information Service (NTIS)

The electrophoretic mobilities of ribosomal ribonucleic acids (RNA) from cultured mammalian (HeLa, Vero, MDBK), avian (chick embryo), and bacterial (Escherichia coli) cells, and RNA species extracted from selected viruses (Sindbis, polio, tobacco mosaic, ...

F. L. Schaffer M. E. Soergel D. C. Straube

1971-01-01

371

A new multiphasic buffer system for benzyldimethyl-n-hexadecylammonium chloride polyacrylamide gel electrophoresis of proteins providing efficient stacking.  

PubMed

Acidic PAGE systems using cationic detergents such as benzyldimethyl-n-hexadecylammonium chloride (16-BAC) or CTAB have proven useful for the detection of methoxy esters sensitive to alkaline pH, resolving basic proteins such as histones and membrane proteins. However, the interesting phosphate-based system suffered from poor stacking, resulting in broadened bands and long running times. Therefore, a new 16-BAC PAGE system based on the theory of moving boundary electrophoresis with properties comparable to the classical SDS-PAGE system was designed. As a result a new multiphasic analytical 16-BAC PAGE system providing efficient stacking and significantly shorter running times is presented here. It is based on acetic acid and methoxyacetic acid as common ion constituents. This PAGE system takes advantage of the additional counter stacking effect due to a cross boundary electrophoresis system resulting from the selected buffer constituents. Furthermore, the concentration of 16-BAC was optimized by determining its previously unknown CMC. Due to efficient focusing of the introduced tracking dye, methyl green, termination of electrophoresis can now be more easily followed as compared to the Schlieren line. PMID:16331586

Kramer, Michael L

2006-02-01

372

Experimental 3D dosimetry around a high-dose-rate clinical 192Ir source using a polyacrylamide gel (PAG) dosimeter  

Microsoft Academic Search

It is well known that the experimental dosimetry of brachytherapy sources presents a challenge. Depending on the particular dosimeter used, measurements can suffer from poor spatial resolution (ion chambers), lack of 3D information (film) or errors due to the presence of the dosimeter itself distorting the radiation flux. To avoid these problems, we have investigated the dosimetry of a clinical

M. McJury; P. D. Tapper; V. P. Cosgrove; P. S. Murphy; S. Griffin; M. O. Leach; S. Webb; M. Oldham

1999-01-01

373

Native American Identity  

ERIC Educational Resources Information Center

Many issues and elements--including ethnic nomenclature, racial attitudes, and the legal and political status of American Indian nations and Indian people--influence Native American identity. (Contains 3 notes.)

Horse, Perry G.

2005-01-01

374

Alaska Native Science Commission  

NSDL National Science Digital Library

This is the homepage of the Alaska Native Science Commission (ANSC), an organization dedicated to bringing together research and science in partnership with the Native community. Site materials include information on Alaska Native communities; a searchable database of contacts for community knowledge and a directory of local, statewide, and federally recognized Alaska Native agencies. There is also information on organizational ethics and protocols, regulatory agencies, a browsable database of research projects, and information on sources of funding. The Key Issues page provides information on issues of concern, such as avian flu, climate change, observations about contaminants and environmental change, traditional knowledge systems, traditional foods, and views on climate change and ecology. For students, there is information on einternship and scholarship opportunities. The publications page provides access to archived newsletters, presentations, and reports.

2010-10-05

375

Native American Tribal Websites.  

ERIC Educational Resources Information Center

|Lists Web sites maintained by 38 different Native American nations that deal with topics ranging from tribal history, news, arts and crafts, tourism, entertainment, and commerce. Represented nations include Apache, Blackfeet, Creek, Iroquois, Mohegan, and Sioux. (CMK)|

Miller, Eric L.

1999-01-01

376

Native American Tribal Websites.  

ERIC Educational Resources Information Center

Lists Web sites maintained by 38 different Native American nations that deal with topics ranging from tribal history, news, arts and crafts, tourism, entertainment, and commerce. Represented nations include Apache, Blackfeet, Creek, Iroquois, Mohegan, and Sioux. (CMK)

Miller, Eric L.

1999-01-01

377

California Native Plant Society  

NSDL National Science Digital Library

This website presents the California Native Plant Society, a national leader in biological diversity conservation science and advocacy. Established in 1965, the CNPS "is a statewide non-profit organization of amateurs and professionals with a common interest in California's native plants." The site provides a variety of information and resources useful to botanists and native plant enthusiasts alike. One notable feature is the site's Photo Gallery which contains many beautiful annotated photos from different parts of California. The site links to the Inventory of Rare and Endangered Plants presenting "the most recent Inventory data from CNPS, plus thumbnail illustrations, maps, a variety of search tools, and links to additional information." The site also links to information about the Native Plant Conservation Campaign, the Manual of California Vegetation (reported on in the Scout Report for Science & Engineering on December 9, 1998), and to online discussion opportunities.

378

Native Health Research Database  

MedlinePLUS

... THIS APP WITH JAVASCRIPT TURNED OFF. THE NATIVE HEALTH DATABASE REQUIRES JAVASCRIPT IN ORDER TO FUNCTION. PLEASE ... Data and Links, U.S. Census Bureau American Indian Health from the National Library of Medicine Arctic Health ...

379

Long-term, buffer-less, wet gel storage in non-sealed polyethylene bags.  

PubMed

Electrophoresed gels are normally fixed, stained, destained, and dried. Drying is normally carried out with commercial gel dryers or by drying between two cellophane sheets held together by two acrylic frames. Here, we report that stained and destained gels (7.5, 10, or 15%, denaturing or native gels; 0.4 or 1.5 mm in thickness) could be stored wet, unsealed, and without any storage buffer for several months at room temperature within flexible polyethylene bags without significant shrinking or protein diffusion. The gel remains hydrated because of the de facto sealing achieved by the polyethylene sheets (PS) adhering airtightly to the gel on either sides. The microsaturated environment generated by the thin film of water molecules trapped between the gel and the PS, along with the nonporous nature of the PS, apparently protects the gel from cracking as well as shrinking significantly. The intensity of stained proteins increased during storage probably from the slight gel shrinkage observed. Wet gel storage is useful (a) when low abundance protein spots from multiple two-dimensional electrophoresis gels have to be excised for in-gel tryptic digestion or electroelution and (b) for wet gel autoradiography. In addition to avoiding dryer contamination and saving drying time, these bags prevent the moist gel from sticking to X-ray film. Such storage could also prove useful for electrophoretic transfer of fixed and stained gels. PMID:22585508

Kurien, Biji T; Scofield, R Hal

2012-01-01

380

Thermostability of glucose oxidase in silica gel obtained by sol-gel method and in solution studied by fluorimetric method.  

PubMed

The thermostability of glucose oxidase entrapped in silica gel obtained by sol-gel method was studied by thermostimulated fluorescence of FAD at pH 5 and 7 and compared with that of the native enzyme in the solution and at the presence of ethanol. The unfolding temperatures were found to be lower for the enzyme immobilised in gel as compared with the native enzyme but higher as for the enzyme at the presence of ethanol. In gel, the thermal denaturation of glucose oxidase is independent on pH while in solution the enzyme is more stable at pH 5. The investigation the enzyme in different environment by steady-state fluorescence of FAD and tryptophan, synchronous fluorescence and time-resolved fluorescence of tryptophan indicates that the state of the molecule (tertiary structure and molecular dynamics) is different in gel and in solution. The ethanol produced during gel precursor hydrolysis is not the main factor influencing the thermostability of the enzyme but more important are interactions of the protein with the gel lattice. PMID:21300556

Przybyt, Ma?gorzata; Miller, Ewa; Szreder, Tomasz

2011-01-19

381

Analysis of Glucose6Phosphate Dehydrogenaseafter Purification usingGel Electrophoresis and Western Blotting  

Microsoft Academic Search

The matrix used in our work was a polyacrylamide gel of 5% concentration of the acrylamide monomer crosslinked to N,N'-methylene bisacrylamide (bisacrylamide). In order to estimate purity and molecular weight in electrophoresis the surfactant sodium dodecyl sulfate (SDS) is used. b-mercaptoethanol (BME) was applied to reduce the disulfide bonds and allow determination of migration by molecular weight only and not

Ivon Brito

2002-01-01

382

Clustering of Clinical Strains of Helicobacter pylori Analyzed by Two-Dimensional Gel Electrophoresis  

Microsoft Academic Search

Strain variations of Helicobacter pylori have been tested by numerous methods and compared among different patient groups. The aim of this study was to investigate whether H. pylori expresses disease-specific proteins that can be detected by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). H. pylori strains isolated from duodenal ulcer, gastric cancer, and gastritis patients were analyzed. Extensive variation in spot

HELENA ENROTH; T. Akerlund; ANNA SILLEN; LARS ENGSTRAND

2000-01-01

383

State-of-the-art two-dimensional gel electrophoresis: a key tool of proteomics research  

Microsoft Academic Search

Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) is the most popular and versatile method of protein separation among a rapidly growing array of proteomics technologies. Based on two distinct procedures, it combines isoelectric focusing (IEF), which separates proteins according to their isoelectric point (pI), and SDS-PAGE, which separates them further according to their molecular mass. At present, 2D-PAGE is capable of simultaneously

Odile Carrette; Pierre R Burkhard; Jean-Charles Sanchez; Denis F Hochstrasser

2006-01-01

384

Analysis of high density lipoproteins by a modified gradient gel electrophoresis method  

Microsoft Academic Search

A high resolution electrophoretic method has been developed to separate plasma high density lipoprotein (HDL) particles by size using 4-3076 polyacrylamide agarose (PAA) gradient gels, Sudan black B staining, and laser densitometry. Fourteen distinct HDL bands were observed with HDL-1 being designated as the largest particle and HDL-14 as the smallest particle. HDL-1 was similar in size to ferritin (Stokes

Zhengling Li; Judith R. McNamara; Jose M. Ordovas; Ernst J. Schaeferl

385

Multi-scale rheological perspective to polymer solutions and gels in EOR  

Microsoft Academic Search

Polymer flooding for enhanced oil recovery (EOR), especially using polyacrylamide (PAM) based systems, gradually became the\\u000a largest non-Newtonian fluid process of economic significance. Yet, the mechanistic understanding lags behind. In this paper,\\u000a the relations of structures — rheological properties — EOR applications were reviewed and some recent laboratory studies on\\u000a associated PAM and PAM soft gels were introduced. The multi

Xu-long Cao; Zheng-quan Li; Qun-ling Zhang; Gang Wang; Yuan-ze Xu

2007-01-01

386

Problems in sampling the Native American and Alaska Native populations  

Microsoft Academic Search

Selecting a scientific national sample of Native Americans and Alaska Natives is difficult for at least four reasons: (1) they are a small proportion of the total population, (2) they are not so segregated that geographic oversampling can reach most of the population, (3) criteria for deciding who is a member of the Native American and Alaska Native population are

EUGENE P. ERICKSEN

1997-01-01

387

Microfluidic device having an immobilized pH gradient and PAGE gels for protein separation and analysis  

SciTech Connect

Disclosed is a novel microfluidic device enabling on-chip implementation of a two-dimensional separation methodology. Previously disclosed microscale immobilized pH gradients (IPG) are combined with perpendicular polyacrylamide gel electrophoresis (PAGE) microchannels to achieve orthogonal separations of biological samples. Device modifications enable inclusion of sodium dodecyl sulfate (SDS) in the second dimension. The device can be fabricated to use either continuous IPG gels, or the microscale isoelectric fractionation membranes we have also previously disclosed, for the first dimension. The invention represents the first all-gel two-dimensional separation microdevice, with significantly higher resolution power over existing devices.

Sommer, Gregory J.; Hatch, Anson V.; Singh, Anup K.; Wang, Ying-Chih

2012-12-11

388

Separation of Membrane Protein Complexes by Native LDS-PAGE.  

PubMed

Gel electrophoresis has become one of the most important methods for the analysis of proteins and protein complexes in a molecular weight range of 1-10(7) kDa. The separation of membrane protein complexes remained challenging to standardize until the demonstration of Blue Native PAGE in 1991 [1] and Clear Native PAGE in 1994 [2]. We present a robust protocol for high-resolution separation of photosynthetic complexes from Arabidopsis thaliana using lithium dodecyl sulfate as anion in a modified Blue Native PAGE (LDS-PAGE). Here, non-covalently bound chlorophyll is used as a sensitive probe to characterize the assembly/biogenesis of the pigment-protein complexes essential for photosynthesis. The high fluorescence yield recorded from chlorophyll-binding protein complexes can also be used to establish the separation of native protein complexes as an electrophoretic standard. PMID:24136555

Arnold, Janine; Shapiguzov, Alexey; Fucile, Geoffrey; Rochaix, Jean-David; Goldschmidt-Clermont, Michel; Eichacker, Lutz Andreas

2014-01-01

389

Native Knowledge in the Americas.  

ERIC Educational Resources Information Center

|Native American science is defined as activities of native peoples of the New World in observing physical phenomena and attempting to explain and control them. Problems in studying native science, ethnoscience and native science, archaeostronomy and ethnoastronomy, ethnobotany, agriculture, technology, and future directions are discussed. (JN)|

Kidwell, Clara Sue

1985-01-01

390

CONFORMANCE IMPROVEMENT USING GELS  

SciTech Connect

This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the flow capacity of fractures (with widths from 1 to 4 mm) during brine and oil flow after placement. Regardless of gel age before placement, very little gel washed out from the fractures during brine or oil flow. However, increased brine or oil flow rate and cyclic injection of oil and water significantly decreased the level of permeability reduction. A particular need exists for gels that can plug large apertures (e.g., wide fractures and vugs). Improved mechanical strength and stability were demonstrated (in 1- to 4-mm-wide fractures) for a gel that contained a combination of high- and low-molecular weight polymers. This gel reduced the flow capacity of 2- and 4-mm-wide fractures by 260,000. In a 1-mm-wide fracture, it withstood 26 psi/ft without allowing any brine flow through the fracture. Cr(III)-acetate-HPAM gels exhibited disproportionate permeability reduction in fractures. The effect was most pronounced when the gel was placed as gelant or partially formed gels. The effect occurred to a modest extent with concentrated gels and with gels that were ''fully formed'' when placed. The effect was not evident in tubes. We explored swelling polymers for plugging fractures. Polymer suspensions were quickly prepared and injected. In concept, the partially dissolved polymer would lodge and swell to plug the fracture. For three types of swelling polymers, behavior was promising. However, additional development is needed before their performance will be superior to that of conventional gels.

Randall S. Seright

2003-09-01

391

Hydrocarbon recovery process using an in situ silicate/polymer gel  

SciTech Connect

This patent describes a process for treating a porous earthen mix with a silicate/polymer gel. The process consists of two steps. The first step is the injection into the matrix of an undried, water-soluble silicate and a gelling agent selected from water-soluble strong acids or water-soluble salts of strong acids. The second step consists of reacting a mixture of the partially hydrolyzed polyacrylamide, silicate and gelling agent in the matrix to form the silicate/polymer gel in situ.

Norton, C.J.

1986-01-14

392

Fluid diversion and sweep improvement with chemical gels in oil recovery processes. Final report  

SciTech Connect

The objectives of this project were to identify the mechanisms by which gel treatments divert fluids in reservoirs and to establish where and how gel treatments are best applied. Several different types of gelants were examined, including polymer-based gelants, a monomer-based gelant, and a colloidal-silica gelant. This research was directed at gel applications in water injection wells, in production wells, and in high-pressure gas floods. The work examined how the flow properties of gels and gelling agents are influenced by permeability, lithology, and wettability. Other goals included determining the proper placement of gelants, the stability of in-place gels, and the types of gels required for the various oil recovery processes and for different scales of reservoir heterogeneity. During this three-year project, a number of theoretical analyses were performed to determine where gel treatments are expected to work best and where they are not expected to be effective. The most important, predictions from these analyses are presented. Undoubtedly, some of these predictions will be controversial. However, they do provide a starting point in establishing guidelines for the selection of field candidates for gel treatments. A logical next step is to seek field data that either confirm or contradict these predictions. The experimental work focused on four types of gels: (1) resorcinol-formaldehyde, (2) colloidal silica, (3) Cr{sup 3+}(chloride)-xanthan, and (4) Cr{sup 3+}(acetate)-polyacrylamide. All experiments were performed at 41{degrees}C.

Seright, R.S.; Martin, F.D.

1992-09-01

393

Analysis of Syneresis of HPAm\\/Cr(II) and HPAm\\/Cr(III) Acetate Gels Through H Nuclear Magnetic Resonance, Bottle Testing, and UV-vis Spectroscopy  

Microsoft Academic Search

Polymer solutions with 7500 mg\\/L of partly hydrolyzed polyacrylamide were crosslinked with Cr(III) acetate 50% active, Cr(III) acetate hydroxide, and Cr(II) acetate respectively. A syneresis-inducing polymer to crosslinker weight ratio of 5\\/1 was employed. An empirical correlation was found between H NMR data and gel syneresis. Chromium speciation indicated that at the experimental conditions used aging the gels did not

S. M. Vargas-Vasquez; L. B. Romero-Zerón; B. MacMillan

2009-01-01

394

Liquid chromatography and differential scanning calorimetry studies on the states of water in hydrophilic polymer gel packings in relation to retention selectivity  

Microsoft Academic Search

The amounts of water which exhibit selectivity to solutes in water-swollen hydrophilic polymer gel packings were determined by a liquid chromatographic method designed on the basis of the mobile phase electrolyte effects on the retention of ionic solutes. The estimated amounts of the water in three types of water-swollen hydrophilic polymer gels, a cross-linked dextran, poly(vinyl alcohol) and polyacrylamide, agree

Masami Shibukawa; Kaoru Aoyagi; Ryosaku Sakamoto; Koichi Oguma

1999-01-01

395

CONFORMANCE IMPROVEMENT USING GELS  

SciTech Connect

This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate, (3) using partially formed gels, (4) using combinations of high and low molecular weight (Mw) polymers, (5) using secondary crosslinking reactions, (6) injecting un-hydrated polymer particles, and (7) incorporating particulates. All of these methods showed promise in some aspects, but required performance improvements in other aspects. All materials investigated to date showed significant performance variations with fracture width. High pressure gradients and limited distance of penetration are common problems in tight fractures. Gravity segregation and low resistance to breaching are common problems in wide fractures. These will be key issues to address in future work. Although gels can exhibit disproportionate permeability reduction in fractures, the levels of permeability reduction for oil flow are too high to allow practical exploitation in most circumstances. In contrast, disproportionate permeability reduction provided by gels that form in porous rock (adjacent to the fractures) has considerable potential in fractured systems.

Randall S. Seright

2004-09-30

396

Hydrolysis and precipitation of polyacrylamides in hard brines at elevated temperatures  

SciTech Connect

Laboratory data are used to show that commercial polyacrylamides hydrolyze to an equilibrium degree that depends on the temperature of hydrolysis but is largely independent of the brine composition. At greater than 20 ppm hardness levels, polyacrylamide solutions pass through a sharp cloud point as their temperature is raised. This cloud-point temperature depends primarily on the hardness level of the brine and the degree of hydrolysis of the polymer, with lesser dependency on polymer molecular weight and polymer concentration. Indications are that these cloudy solutions cause plugging of porous media. Therefore, a polymer solution is potentially useful only below its cloud-point temperature. For application in a given reservoir, the temperature and frequently the hardness of the water are fixed. If a polyacrylamide hydrolyzes at reservoir conditions to where its cloud point in the field water falls below the reservoir temperature, it is not suitable for polymer flooding in that reservoir.

Moradi-Araghi, A.; Doe, P.H.

1987-05-01

397

Ocular Proteomics with Emphasis on Two-Dimensional Gel Electrophoresis and Mass Spectrometry  

PubMed Central

The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure reliable results. Current methods of protein staining for 2D-PAGE, protein labelling for two-dimensional difference gel electrophoresis, gel-based expression analysis and protein identification by MS are summarised. The uses of gel-free MS-based strategies (MuDPIT, iTRAQ, ICAT and SILAC) are also discussed. Proteomic technologies promise to shed new light onto ocular disease processes that could lead to the discovery of strong novel biomarkers and therapeutic targets useful in many ophthalmic conditions.

2010-01-01

398

Accelerated Coomassie Blue staining and destaining of SDS-PAGE gels with application of heat.  

PubMed

Coomassie Brilliant Blue is commonly used for the detection of proteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, owing to its reliability and simplicity. Here, we report dramatically decreased protein staining and destaining time, as well as significantly increased detection sensitivity with the application of enhanced heat. The staining time was 5 min at 55, 62.5, or 70°C for a 1.5-mm gel, while it took 45, 45, and 20 min, respectively, for destaining. The staining time could be reduced to 1 min for a 0.8 mm gel stained at 65°C, to 2 min at 60°C and 5 min at 55°C. The destaining of proteins analyzed on a 0.8 mm gel could be accomplished in 8, 15, and 20 min at 65, 60, and 55°C, respectively. Application of heat, thus, enables proteins to be stained and destained rapidly, as well as enhancing detection sensitivity. PMID:22585512

Kurien, Biji T; Scofield, R Hal

2012-01-01

399

CONFORMANCE IMPROVEMENT USING GELS  

Microsoft Academic Search

This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts

Randall S. Seright

2004-01-01

400

CONFORMANCE IMPROVEMENT USING GELS  

SciTech Connect

This technical progress report describes work performed from September 1, 2003, through February 29, 2004, for the project, ''Conformance Improvement Using Gels.'' We examined the properties of several ''partially formed'' gels that were formulated with a combination of high and low molecular weight HPAM polymers. After placement in 4-mm-wide fractures, these gels required about 25 psi/ft for brine to breach the gel (the best performance to date in fractures this wide). After this breach, stabilized residual resistance factors decreased significantly with increased flow rate. Also, residual resistance factors were up to 9 times greater for water than for oil. Nevertheless, permeability reduction factors were substantial for both water and oil flow. Gel with 2.5% chopped fiberglass effectively plugged 4-mm-wide fractures if a 0.5-mm-wide constriction was present. The ability to screen-out at a constriction appears crucial for particulate incorporation to be useful in plugging fractures. In addition to fiberglass, we examined incorporation of polypropylene fibers into gels. Once dispersed in brine or gelant, the polypropylene fibers exhibited the least gravity segregation of any particulate that we have tested to date. In fractures with widths of at least 2 mm, 24-hr-old gels (0.5% high molecular weight HPAM) with 0.5% fiber did not exhibit progressive plugging during placement and showed extrusion pressure gradients similar to those of gels without the fiber. The presence of the fiber roughly doubled the gel's resistance to first breach by brine flow. The breaching pressure gradients were not as large as for gels made with high and low molecular weight polymers (mentioned above). However, their material requirements and costs (i.e., polymer and/or particulate concentrations) were substantially lower than for those gels. A partially formed gel made with 0.5% HPAM did not enter a 0.052-mm-wide fracture when applying a pressure gradient of 65 psi/ft. This result suggests a lower limit of fracture width for entry of formed or partially formed gels (when reasonable pressure gradients are applied). In unfractured porous rock, we investigated the time dependence of oil and water permeabilities during various cycles of oil and water injection after placement of a Cr(III)-acetate-HPAM gel. Permeability to water stabilized rapidly (within 1 pore volume, PV), while permeability to oil stabilized gradually over the course of 100 PV. The behavior was surprisingly insensitive to core material (strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene), core permeability (740 to 10,000 md), and applied pressure gradient (10 to 100 psi/ft).

Randall S. Seright

2004-03-01

401

Microwave initiated synthesis of polyacrylamide grafted Psyllium and its application as a flocculant.  

PubMed

This paper reports a novel microwave initiated method for synthesis of polyacrylamide grafted Psyllium (Psy-g-PAM). Psyllium was modified through grafting of polyacrylamide (PAM) chains on it using microwave radiations only, in absence of any other free radical initiator. The grafting was confirmed by intrinsic viscosity study and characterization techniques like FTIR spectroscopy, elemental analysis (C, H, N, O and S) and SEM morphology study. Further, the flocculation efficacy of the synthesized graft copolymers was studied in kaolin and coal fine suspension through standard 'Jar test' procedure. PMID:22210527

Sen, Gautam; Mishra, Sumit; Rani, G Usha; Rani, Priti; Prasad, Rajesh

2011-12-23

402

Orthogonally bifunctionalised polyacrylamide nanoparticles: a support for the assembly of multifunctional nanodevices  

NASA Astrophysics Data System (ADS)

Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper-catalysed azide-alkyne cycloaddition and isothiocyanate chemistry.Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper-catalysed azide-alkyne cycloaddition and isothiocyanate chemistry. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11947a

Giuntini, F.; Dumoulin, F.; Daly, R.; Ahsen, V.; Scanlan, E. M.; Lavado, A. S. P.; Aylott, J. W.; Rosser, G. A.; Beeby, A.; Boyle, R. W.

2012-03-01

403

Native American Case Studies  

NSDL National Science Digital Library

The Native American Case Studies collection includes more than 80 original, research-based teaching cases focusing on contemporary issues in Indian Country. Teaching notes accompany each case. These can be downloaded and used at no cost. Additional website resources include information on teaching with cases and assessment. Guidelines for submitting cases are also available.

College, The E.; College, Northwest I.; College, Salish K.; College, Grays H.

404

Native American Education.  

ERIC Educational Resources Information Center

|Examines an 1876 letter from a missionary to Ferdinand V. Hayden in the context of the U.S. government's policy of instituting religious education and training for Native Americans. Provides a photocopy of the letter and outlines class activities designed to help students analyze the document. (DB)|

Mueller, Jean West; Schamel, Wynell Burroughs

1990-01-01

405

Native American Museums: \\  

Microsoft Academic Search

Native Americans have opened some 250 museums and cultural centers in the last twenty years for several reasons: to re-possess their patrimony, memorize their culture and maintain their identity. Their museums are spaces of cultural and educational experience, replacing split families who no longer transmit traditional values orally. They safeguard oral testimonies of the old people (recordings) and the sacred

Gérard Selbach

406

Native American Arts.  

National Technical Information Service (NTIS)

The video shows a richly varied and vivid impression of the unique historic and esthetic values, images, and traditions that are being rigorously developed by Native Americans in virtually every art form today. It presents a human survey of the modern eff...

1994-01-01

407

Native American Arts.  

National Technical Information Service (NTIS)

Shows a richly varied and vivid impression of the unique historic and esthetic values, images, and traditions that are being rigorously developed by native americans in virtually every art form today. Presents a human survey of the modern efforts in educa...

1994-01-01

408

Native Americans in Utah  

NSDL National Science Digital Library

This activity will help you learn about some of the early Native American inhabitants of Utah. Look at the following websites and see if you can find some information about one of the following groups of Native Americans in Utah. History of Utah Tribes Goshute Goshute Indians Utah History To Go: Goshute Indians Goshute Indian Reservation Utah History To Go: The Utes, Paiutes, and Goshutes Navajo People of the Colorado Plateau: Navajo (Dine) History of the Navajo Indians of Utah Navajo Navajo Indians Paiute Paiute Indians of Utah Paiute Native American Desert Peoples: The Paiute People Paiute Indians of Utah Utah History To Go--Piaute Indians Utah History To Go: The Utes, Paiutes, and Goshutes Shoshone Shoshone History of the Shoshone Indians Shoshoni Lewis and Clark: Native Americans--Shoshone Indians Ute Utah History To Go: Ute Indians People of the Colorado Plateau: The Ute Indians Story of the Ute Tribe Northern Ute Indian History Utah History To Go: The Utes, Paiutes, and Goshutes ...

Bates, Albion M.

2006-10-10

409

Native American Health  

MedlinePLUS

... racial or ethnic group has specific health concerns. Differences in the health of groups can result from: Genetics Environmental factors Access to care Cultural factors On this page, you'll find links to health issues that affect Native-Americans.

410

Does nativity matter?  

Microsoft Academic Search

The Russian Federation has experienced simultaneous declines in health and rises in international migration. Guided by the “healthy migrant effect” found elsewhere, we examine two questions. First, do the foreign-born in the Russian Federation exhibit better overall health than the native-born? Second, to the extent positive health selectivity exists, is it transferred to the second generation? Using the first wave

Cynthia Buckley; Erin Hofmann; Yuka Minagawa

2011-01-01

411

Responsive Gel-Gel Phase Transitions in Artificially Engineered Protein Hydrogels  

NASA Astrophysics Data System (ADS)

Artificially engineered protein hydrogels provide an attractive platform for biomedical materials due to their similarity to components of the native extracellular matrix. Engineering responsive transitions between shear-thinning and tough gel phases in these materials could potentially enable gels that are both shear-thinning and tough to be produced as novel injectable biomaterials. To engineer a gel with such transitions, a triblock copolymer with thermoresponsive polymer endblocks and an artificially engineered protein gel midblock is designed. Temperature is used to trigger a transition from a single network protein hydrogel phase to a double network phase with both protein and block copolymer networks present at different length scales. The thermodynamics of network formation and resulting structural changes are established using small-angle scattering, birefringence, and dynamic scanning calorimetry. The formation of the second network is shown to produce a large, nonlinear increase in the elastic modulus as well as enhancements in creep compliance and toughness. Although the gels show yielding behavior in both the single and double network regimes, a qualitative change in the deformation mechanism is observed due to the structural changes.

Olsen, B. D.

2012-02-01

412

Studying Native America: Problems and Prospects.  

ERIC Educational Resources Information Center

Based on a conference, this volume examines the past, present, and future of Native American studies. Native American studies seeks to understand Native Americans, America, and the world from a Native American indigenous perspective, and thereby broaden the education of both Native and non-Native Americans. Part 1 asks who Native Americans are…

Thornton, Russell, Ed.

413

Studying Native America: Problems and Prospects.  

ERIC Educational Resources Information Center

|Based on a conference, this volume examines the past, present, and future of Native American studies. Native American studies seeks to understand Native Americans, America, and the world from a Native American indigenous perspective, and thereby broaden the education of both Native and non-Native Americans. Part 1 asks who Native Americans are…

Thornton, Russell, Ed.

414

Gel electrophoresis of linear and star-branched DNA.  

PubMed

The electrophoretic mobility of double-stranded DNA in polyacrylamide gel is investigated using an activated hopping model for the transport of a charged object within a heterogeneous medium. The model is premised upon a representation of the DNA path through the gel matrix as a series of traps with alternating large and small cross sections. Calculations of the trap dimensions from gel data show that the path imposes varying degrees of confinement upon migrating analytes, which retard their forward motion in a size-dependent manner. An expression derived for DNA mobility is shown to provide accurate predictions for the dynamics of linear DNA (67-622 bp) in gels of multiple concentrations. For star-branched DNA, the incorporation within the model of a length scale previously proposed to account for analyte architecture [Yuan et al., Anal. Chem. 78, 6179 (2006)] leads to mobility predictions that compare well with experimental results for a wide range of DNA shapes and molecular weights. PMID:22304125

Lau, Henry W; Archer, Lynden A

2011-12-22

415

Agarose Gel Demos  

NSDL National Science Digital Library

This video, presented by WGBH, is a great overview of how to prepare Agarose gel for electrophoresis. The video goes in-depth with the finer points including how to insert the pipette as to not disturb the gel and get the best results. This video would be useful for anyone in biochemistry or molecular biology fields. This video would also be helpful for instructors looking to provide their students with an overview on how to prepare Agarose gel. Educators will also find a background essay, discussion questions, and standards alignment for the material.

2010-09-15

416

Application of a PAGAT/MgCl2 gel for dose measurements in a 150 MeV proton beam  

NASA Astrophysics Data System (ADS)

The purpose of this study is to evaluate the dose response of polyacrylamide-based gel (PAGAT) when irradiated with clinical proton beams. Recently inorganic salt additive in gel has been reported to improve dose sensitivity substantially. We attempted to add MgCl2 (0.5M) to regular PAGAT gel in order to compensate its lower radiation sensitivity. The spin-spin relaxation rates (R2) as dose readout was calculated from MR imaging after irradiation with 150MeV proton beam. The dose sensitivity was discussed from the slope at dose-R2 response curve. As the result, the sensitivity of the gel with MgCl2 is approximately 3 times higher than that of regular PAGAT gel without spoiling dose response stability under the various irradiation conditions such as dose rate and dose integration.

Tominaga, T.; Hayashi, S.; Usui, S.; Kawamura, H.; Katahira, K.

2013-06-01

417

New resin gel for uranium determination by diffusive gradient in thin films technique.  

PubMed

A new resin gel based on Spheron-Oxin(®) chelating ion-exchanger with anchored 8-hydroxyquinoline functional groups was tested for application in diffusive gradient in thin film technique (DGT) for determination of uranium. Selectivity of uranium uptake from model carbonate loaded solutions of natural water was studied under laboratory conditions and compared with selectivity of the conventional Chelex 100 based resin gel. The affinity of Spheron-Oxin(®) functional groups enables determination of the overall uranium concentration in water containing carbonates up to the concentration level of 10(2) mg L(-1). The effect of uranium binding to the polyacrylamide (APA) and agarose diffusive gels (AGE) was also studied. Uranium is probably bound in both gels by a weak interaction with traces of acrylic acid groups in the structure of APA gel and with pyruvic and sulfonic acid groups in the AGE gel. These sorption effects can be eliminated to the negligible level by prolonged deployment of DGT probes or by disassembling probes after the 1-2 days post-sampling period that is sufficient for release of uranium from diffusive gel and its sorption in resin gel. PMID:21167996

Gregusova, Michaela; Docekal, Bohumil

2010-11-09

418

University students’ perceptions of native and non?native teachers  

Microsoft Academic Search

The employment of native teachers of English in countries where English is a foreign language, coupled with a growing concern over teaching effectiveness, has led to collecting data about teachers’ performance through student feedback. Not much research has been carried out in Turkey to evaluate the process and output of language teaching by native and non?native teachers from students’ points

Evrim Üstünlüoglu

2007-01-01

419

STABILITY ANALYSIS OF SOIL AGGREGATES TREATED WITH ANIONIC POLYACRYLAMIDES OF DIFFERENT MOLECULAR FORMULATIONS  

Microsoft Academic Search

Soil sealing and erosion on agricultural fields is a severe problem that often leads to increased runoff and decreased soil quality. Much re- search has been conducted using polyacrylamide (PAM) to control soil sealing and reduce erosion, yet few studies have attempted to determine the most effective molecular formulation(s) of PAM. Our objective was to examine the ability of a

V. Steven Greenl; Diane E. Stott; John G. Graveel; L. Darrell Norton

2004-01-01

420

Effectiveness of Polyacrylamide (PAM) in Improving Runoff Water Quality From Construction Sites  

Microsoft Academic Search

Erosion from construction sites significantly affects water quality in receiving streams. A rainfall simulator was used to evaluate the effectiveness of different methods for controlling erosion from construction sites. Erosion control methods investigated included dry and liquid applications of polyacrylamide (PAM), hydroseed, and straw mulch. Fertilizer was also applied to each plot to examine the effectiveness of the methods in

Michelle L. Soupir; Saied Mostaghimi; Amanda Masters; Katherine A. Flahive; David H. Vaughan; Aida Mendez; Phillip W. McClellan

2004-01-01

421

Soil aggregate stability as affected by clay mineralogy and polyacrylamide addition  

Technology Transfer Automated Retrieval System (TEKTRAN)

The addition of polyacrylamide (PAM) to soil leads to stabilization of existing aggregates and improved bonding between, and aggregation of adjacent soil particles However, the dependence of PAM efficacy as an aggregate stabilizing agent on soil-clay mineralogy has not been studied. Sixteen soil sam...

422

Effects of Polyacrylamide Molecular Weight, Soil Texture and Electrolyte Concentration on Drainable Porosity and Aggregate Stability  

Technology Transfer Automated Retrieval System (TEKTRAN)

The literature reports on the intricate relations between soil type and molecular weight (MW) of polyacrylamide (PAM) with respect to PAM efficacy as a soil conditioner. This relation may depend on the ability of PAM to penetrate into aggregates and thus stabilize both outer and inner aggregate surf...

423

Polyacrylamide Molecular Weight and Phosphogypsum Effects on Infiltration and Erosion in Semi-Arid Soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seal formation at the surface of semi-arid soils during rainstorms reduces soil infiltration rate (IR) and causes runoff and erosion. Surface application of dry anionic polyacrylamide (PAM) with high molecular weight (MW) has been found to be effective in stabilizing soil aggregates, and decreasing ...

424

Silicone rubber-hydrogel composites as polymeric biomaterials. IX. Composites containing powdery polyacrylamide hydrogel.  

PubMed

A composite material has been prepared consisting of a silicone rubber matrix and particulate lightly cross-linked polyacrylamide hydrogel. The material, resembling common silicone rubber, is hydrophilic and swells in water like hydrogels. The polyacrylamide has a high specific surface area, a relatively low content of water-soluble low-molecular-weight compounds and, owing to its non-ionogenic character, a pH-independent swelling degree. For the composite material consisting of the silicone rubber and very fine powdery cross-linked polyacrylamide, we have measured the rate of swelling in water, the mechanical properties (tensile strength, break elongation, hardness, resilience), biological properties (implantation test, cytotoxicity, cell cultivation) and UV absorption of its water extracts. The polyacrylamide and polysiloxane purity, as the composite material starting components, has been determined to be satisfactory. As a result, a high swelling rate of the prepared composite material has been observed, resulting in reaching more than 70% wt of water of the equilibrium swelling. The results show that the composite material is suitable for biological and medical use. PMID:9239469

Hron, P; Slechtová, J; Smetana, K; Dvoránková, B; Lopour, P

1997-08-01

425

Polyacrylamide and Water Quality Effects on Infiltration in Sandy Loam Soils  

Microsoft Academic Search

Slow infiltration rates constrain effective and economical irrigation in some sandy loam soils in California. Polyacrylamide (PAM) has in- creased soil infiltration in some areas, especially in soils high in clay or silt. Field trials near Fresno, CA, with PAM failed to show improved infiltration. Laboratory experiments were conducted to investigate PAM effect on infiltration of various quality waters in

Husein A. Ajwa; Thomas J. Trout

2006-01-01

426

Feasibility study of the anaerobic digestion of dewatered pig slurry by means of polyacrylamide  

Microsoft Academic Search

Liquid livestock waste can be managed by separating liquid and solid fractions then treating each separately by applying best available technology, such as anaerobic digestion for the solid fraction. There is an increasing use of polyacrylamide (PAM) as a flocculant agent to improve solid–liquid separation. In the present work, the anaerobic toxicity of PAM residues and the optimal range of

E. Campos; M. Almirall; J. Mtnez-Almela; J. Palatsi; X. Flotats

2008-01-01

427

Adsorption of Magnetic Nanoparticles onto Polyacrylamide Chains in Dilute Polymer Solutions and Ferrogel Networks  

Microsoft Academic Search

We study iron oxide nanoparticles stabilized by citrate ligands interacting with long linear poly(acrylamide) chains in the regime where the diluted chains are decorated by many smaller magnetic nanoparticles. The strength of adsorption of the particles onto polymer increases when the unbound citrate concentration decreases, as evidenced by the faster translational dynamics of the particle-polymer complexes and the slower rotational

Delphine El Kharrat; Olivier Sandre; Pedro Licinio; Régine Perzynski

2004-01-01

428

Technological Solutions for Erosion Control and Water Clarification using Polyacrylamide (PAM) and PAM blends  

Microsoft Academic Search

Years of research, corporate publications, patents and trademarks have led to a greatly improved and cost efficient erosion control technology. Development of new polyacrylamide (PAM) blends and delivery methodologies has resulted in a whole new class of in-situ erosion control and water clarification tools. Multi-disciplinary environmental industry projects for mining, construction, water treatment and biological research have proven this class

William Gowdy; Jerry Hanna; Steven R. Iwinski; Dave Martin

429

Orthogonally bifunctionalised polyacrylamide nanoparticles: a support for the assembly of multifunctional nanodevices.  

PubMed

Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper-catalysed azide-alkyne cycloaddition and isothiocyanate chemistry. PMID:22354385

Giuntini, F; Dumoulin, F; Daly, R; Ahsen, V; Scanlan, E M; Lavado, A S P; Aylott, J W; Rosser, G A; Beeby, A; Boyle, R W

2012-02-21

430

Molecular dimension and interaction parameters of polyacrylamide in water–dimethylsulphoxide mixtures: effect of temperature  

Microsoft Academic Search

The intrinsic viscosities [?] of polyacrylamides having different molecular sizes are measured at 30–50°C temperature in various mixtures of water (good solvent) and dimethylsulphoxide (DMSO, poor solvent). The observed result and the Huggins constant values show a significant variation of cosolvency as a function of solvent composition (?) and temperature. The nature of plots of [?] vs. ?DMSO indicates relative

P Bera; S. K Saha

2001-01-01

431

POLYACRYLAMIDE (PAM) APPLICATION EFFECTIVENESS IN REDUCING SOIL EROSION FROM SUGARCANE FIELDS IN SOUTHERN LOUISIANA  

Technology Transfer Automated Retrieval System (TEKTRAN)

A field experiment was conducted in the spring of 2002 to determine the effectiveness of high molecular weight anionic polyacrylamide (PAM) in stabilizing quarter drains(reducing soil erosion) on fields planted to sugarcane. Quarter drains are small surface ditches perpendicular to sugarcane furrow...

432

USE OF POLYACRYLAMIDE IN SIMULATED LAND APPLICATION OF LAGOON EFFLUENT: PART II. NUTRIENT LOSS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Land application of agricultural wastewater can contribute to eutrophication of water bodies by increasing the quantities of dissolved and particulate nutrients that are transported in runoff during rain storm events. Anionic polyacrylamide (PAM) is a soil amendment that has been shown to reduce so...

433

Effect of carbon dioxide on rheological properties and structure of polyacrylamide solutions  

Microsoft Academic Search

The effect of CO2 on rheological properties and structure of polyacrylamide solutions was studied as a function of pressure, treating time, polymer type and presence of inorganic electrolytes and natural formation rocks. It was found that the serious deterioration of the solution viscosity can be attributed mostly to the change of the solution structure, while the actual molecular degradation plays

I. Lakatos; J. Lakatos-Szabó

1996-01-01

434

Composition and method for enhanced oil recovery utilizing aqueous polyacrylamide solutions  

Microsoft Academic Search

A composition and method are described for the enhanced recovery of liquid hydrocarbons from a subterranean reservoir. There is injected into the reservoir via one or more injection wells a displacement fluid consisting of an aqueous solution of a polyacrylamide thickener and OK Liquid detergent composition. Liquid hydrocarbons are recovered via one or more production wells. The aqueous solution is

1977-01-01

435

Process for manufacture of powdered polyacrylamide from hydrogels for enhanced oil recovery  

Microsoft Academic Search

A process for the preparation of powdered polyacrylamide from hydrogels was developed. An empirical expression relating the\\u000a water and impurity release to the basic processing parameters (ultrasound frequency, time and temperature of release of the\\u000a foreign mixture) was derived.

V. S. Krivoputskii; L. M. Krivoputskaya

2006-01-01

436

Production of a polyacrylamide solution used in an oil recovery process  

SciTech Connect

A process is described for recovering oil from a subterranean oil-bearing formation having performance demands comprising the steps of: determining the performance demands of the formation; determining correlations between an initial polymerization reaction parameter of initiator level and partially hydrolyzed polyacrylamide solution properties of screen factor and viscosity, each correlation having a discontinuity; selecting a value of the initiator level below each discontinuity such that the selected value of the initiator level is capable of producing a partially hydrolyzed polyacrylamide solution having values of the properties of viscosity and screen factor relatively sensitive to varying the initiator level and capable of meeting the performance demands of the formation; producing the partially hydrolyzed polyacrylamide solution having the values of the properties relatively sensitive to varying the initiator level and capable of meeting the performance demands by polymerizing an acrylamide monomer using a polymerization initiator at the selected value; and injecting the partially hydrolyzed polyacrylamide solution into the formation to improve oil recovery therefrom.

Luetzelschwab, W.E.

1987-01-06

437

Actual Performance versus Theoretical Advantages of Polyacrylamide Hydrogel throughout Bedding Plant  

Microsoft Academic Search

An appropriate blend of growing media components increases water holding capacity and reduces irrigation frequency. Synthetic commercial materials, referred to as hydrogels, have remarkable hydrating properties, but can add signifi cantly (about 15%) to the cost of growing media. The literature generally states that the physical characteristics of hydrogels, such as polyacrylamide (PAM), are altered by the presence of divalent

Jonathan M. Frantz; James C. Locke; Dharmalingam S. Pitchay; Charles R. Krause

2005-01-01

438

Detection of phosphorylated T and B cell antigen receptor species by Phos-tag SDS and Blue Native-PAGE  

Microsoft Academic Search

Detection of phospho-proteins and differently phosphorylated forms of the same protein are important in understanding cell behaviour. One novel method is Phos-tag SDS-PAGE. A dinuclear Mn2+ complex that binds to phosphate groups (the Phos-tag) is covalently attached to the polyacrylamide gel matrix. Thus, phosphorylated proteins are retarded in their migration and can be distinguished from their non-phosphorylated counterparts. We applied

Sumit Deswal; Katharina Beck-García; Britta Blumenthal; Elaine P. Dopfer; Wolfgang W. A. Schamel

2010-01-01

439

Combination of native and denaturing PAGE for the detection of protein binding regions in long fragments of genomic DNA  

Microsoft Academic Search

BACKGROUND: In a traditional electrophoresis mobility shift assay (EMSA) a 32P-labeled double-stranded DNA oligonucleotide or a restriction fragment bound to a protein is separated from the unbound DNA by polyacrylamide gel electrophoresis (PAGE) in nondenaturing conditions. An extension of this method uses the large population of fragments derived from long genomic regions (approximately 600 kb) for the identification of fragments

Kristel Kaer; Kert Mätlik; Madis Metsis

2008-01-01

440

Detection of phosphorylated T and B cell antigen receptor species by Phos-tag SDS and Blue Native-PAGE  

Microsoft Academic Search

Detection of phospho-proteins and differently phosphorylated forms of the same protein are important in understanding cell behaviour. One novel method is Phos-tag SDS-PAGE. A dinuclear Mn 2+ complex that binds to phosphate groups (the Phos-tag) is covalently attached to the polyacrylamide gel matrix. Thus, phosphorylated proteins are retarded in their migration and can be distinguished from their non-phosphorylated counterparts. We

Sumit Deswal; Katharina Beck-García; Britta Blumenthal; Elaine P. Dopfer; Wolfgang W. A. Schamel

2009-01-01

441

Native Americans' Interest in Horticulture.  

ERIC Educational Resources Information Center

|Focus groups arranged by local Native American Master Gardeners on two Minnesota reservations determined community interest in extension-horticulture programs. Topics of interest included food preservation and historical Native-American uses of plants. (SK)|

Meyer, Mary Hockenberry

1999-01-01

442

Resources for Native Education Leaders  

NSDL National Science Digital Library

This resource guide lists institutions and programs, dissertations, articles, and books about Native American education leadership in Native organizations and communities. It also includes citations from Leadership Quarterly on the same subject.

Begaye, Tim

2010-11-12

443

Alaska Native Parkinson's Disease Registry.  

National Technical Information Service (NTIS)

This registry initiates a program of epidemiological assessments of PS among Alaska Natives to study the natural history and clinical management of PS, and establishes a database of Alaska native people with PS for public health, research and educational ...

B. A. Trimble

2008-01-01

444

Gelation Rheology and Water Absorption Behavior of Semi-Interpenetrating Polymer Networks of Polyacrylamide and Carboxymethyl Cellulose  

Microsoft Academic Search

Gelation rheology and swelling behavior of novel semi-interpenetrating polymer network (semi-IPN) hydrogels based on polyacrylamide are described. These hydrogels were prepared by solution crosslinking of partially hydrolyzed polyacrylamide and carboxymethyl cellulose (CMC), using chromium triacetate. Effects of CMC content on the gelation process and swelling behavior in tap water and different electrolyte solutions were investigated. Study of the gelation behavior

Jamal Aalaie; Ebrahim Vasheghani-Farahani; Ali Rahmatpour; Mohammad Ali Semsarzadeh

2012-01-01

445

Retention of polyacrylamide by berea sandstone, baker dolomite, and sodium kaolinite during polymer flooding. Paper SPE 8981  

SciTech Connect

Surface charge and accessible surface area control the retention of polyacrylamide by berea sandstone, baker dolomite, and sodium kaolinite. Hydrolysis of polyacrylamide increases retention by materials with a positively charged surface, such as dolomite, and decreases retention, when surface area remains constant, on materials with negatively charged surfaces, such as sandstone. Additives which form a more theta or less effective solvent promote retention. Water becomes a less effective solvent for polyacrylamide when its salt content is increased or when nonsolvents, such as alcohols, are added to it. Berea sandstone cores retained over 50 percent of polyacrylamide injected under all salinities, polyacrylamide concentrations, and degrees of hydrolysis tested and sodium kaolinite retained over 90 percent of all injected polyacrylamide under the same conditions. In contrast, baker dolomite, a high purity dolomite, retains only 17.9 percent of the unhydrolyzed polyacrylamide injected. Since bera sandstone contains 7.5 percent kaolinite, these data suggest that clay content has a significant effect on total polymer retention. Flocculating sodium kaolinite, which reduces its accessible surface area by over 80 percent, reduces retention by 70 percent, from 1217 ..mu..g/g to 360 ..mu..g/g. With other variables held constant, reduction in accessible surface area will reduce retention of polyacrylamide by a porous medium as long as adsorption dominates the retention process. 24 references, 15 figures, 2 tables.

Meister, J.J.; Pledger, H. Jr.; Hogen-Esch, T.E.; Butler, G.B.

1980-01-01

446

Interactions of polyacrylamides used for enhanced oil recovery and reservoir isolates of the sulfate-reducing bacterium Desulfovibrio  

Microsoft Academic Search

The interactions of partially hydrolyzed polyacrylamides utilized in enhanced oil recovery as mobility control agents and reservoir isolates of Desulfovibrio were examined. Produced waters from reservoirs undergoing polymer flooding were sampled to determine the presence and numbers of sulfate-reducing bacteria. The influence of polyacrylamide on the growth of Desulfovibrio under a number of conditions was studied. Brookfield viscosity and screen

1987-01-01

447

EPIDUO Gel Labeling  

Center for Biologics Evaluation and Research (CBER)

Text Version... treated with EPIDUO Gel were dry skin, contact ... of topical products with a strong drying effect can ... Weather extremes, such as wind or cold, may be ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

448

Periodic mesoporous silica gels  

SciTech Connect

We have synthesized monolithic particulate gels of periodic mesoporous silica by adding tetramethoxysilane to a homogeneous alkaline micellar precursor solution. The gels exhibit 5 characteristic length scales over 4 orders of magnitude: fractal domains larger than the particle size (>500 nm), particles that are {approximately}150 to 500 nm in diameter, interparticle pores that are on the order of the particle size, a feature in the gas adsorption measurements that indicates pores {approximately}10-50 nm, and periodic hexagonal arrays of {approximately}3 nm channels within each particle. The wet gel monoliths exhibit calculated densities as low as {approximately}0.02 g/cc; the dried and calcined gels have bulk densities that range from {approximately}0.3-0.5 g/cc. The materials possess large interparticle ({approximately}1.0-2.3 cc/g) and intraparticle ({approximately}0.6 cc/g) porosities.

Anderson, M.T.; Martin, J.E.; Odinek, J.G. [and others

1996-06-01

449

Active DNA gels  

NASA Astrophysics Data System (ADS)

Research into the mechanics and fluctuations of living cells has revealed the key role played by the cytoskeleton, a gel of stiff filaments driven out of equilibrium by force-generating motor proteins. Inspired by the extraordinary mechanical functions that the cytoskeleton imparts to the cell, we sought to create an artificial gel with similar characteristics. We identified DNA, and DNA-based motor proteins, as functional counterparts to the constituents of the cytoskeleton. We used DNA selfassembly to create a gel, and characterized its fluctuations and mechanics both before and after activation by the motor. We found that certain aspects of the DNA gel quantitatively match those of cytoskeletal networks, indicating the universal features of motor-driven, non-equilibrium networks.

Saleh, Omar A.; Fygenson, Deborah K.; Bertrand, Olivier J. N.; Park, Chang Young

2013-02-01

450

Multicomponent biopolymer gels  

Microsoft Academic Search

The structure—property relationship and application of multicomponent protein—polysaccharide and polysaccharide 1—polysaccharide 2 gels are considered. Attention is focused on gels based on mixed solutions of gelatin with dextran, human serum albumin, sodium caseinate, ovalbumin, agarose, methylcellulose, calcium alginate or sodium alginate. The thermodynamic incompatibility of and the formation of complexes by food hydrocolloids greatly affect mechanical and other physicochemical properties

D. V. Zasypkin; E. E. Braudo; V. B. Tolstoguzov

1997-01-01

451

Fluorescent staining of gels.  

PubMed

Certain transition metal complexes show intensive fluorescence when bound to proteins. They can be used to stain gels after electrophoresis with a sensitivity approaching that of silver staining, but in a much simpler and more reproducible procedure. Stains can be prepared easily and at a fraction of the cost of commercially available reagents.Hydrophobic dyes can be used to stain gels without fixing; they do not interfere with later blotting or electro-elution. PMID:22585519

Buxbaum, Engelbert

2012-01-01

452

Gels with magnetic properties  

Microsoft Academic Search

Materials producing strain in magnetic field are known as magnetoelastic or magneto strictive materials. A new type has been\\u000a developed by preparing magnetic field sensitive gels, called ferrogels. Single domain, magnetic particles of colloidal size\\u000a are incorporated into chemically cross-linked polyvinyl-alcohol hydrogels. The finely distributed colloidal particles having\\u000a superparamgnetic behavior couple the shape of the gel to the nonuniform external

L. Barsi; A. Biiki; D. Szabó; M. Zrinyi

453

Conformance Improvement Using Gels  

SciTech Connect

This research project had two objectives. The first objective was to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective was to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil.

Seright, Randall S.; Schrader, Richard; II Hagstrom, John; Wang, Ying; Al-Dahfeeri, Abdullah; Gary, Raven; Marin; Amaury; Lindquist, Brent

2002-09-26

454

Crystallization from Gels  

NASA Astrophysics Data System (ADS)

Among the various crystallization techniques, crystallization in gels has found wide applications in the fields of biomineralization and macromolecular crystallization in addition to crystallizing materials having nonlinear optical, ferroelectric, ferromagnetic, and other properties. Furthermore, by using this method it is possible to grow single crystals with very high perfection that are difficult to grow by other techniques. The gel method of crystallization provides an ideal technique to study crystal deposition diseases, which could lead to better understanding of their etiology. This chapter focuses on crystallization in gels of compounds that are responsible for crystal deposition diseases. The introduction is followed by a description of the various gels used, the mechanism of gelling, and the fascinating phenomenon of Liesegang ring formation, along with various gel growth techniques. The importance and scope of study on crystal deposition diseases and the need for crystal growth experiments using gel media are stressed. The various crystal deposition diseases, viz. (1) urolithiasis, (2) gout or arthritis, (3) cholelithiasis and atherosclerosis, and (4) pancreatitis and details regarding the constituents of the crystal deposits responsible for the pathological mineralization are discussed. Brief accounts of the theories of the formation of urinary stones and gallstones and the role of trace elements in urinary stone formation are also given. The crystallization in gels of (1) the urinary stone constituents, viz. calcium oxalate, calcium phosphates, uric acid, cystine, etc., (2) the constituents of the gallstones, viz. cholesterol, calcium carbonate, etc., (3) the major constituent of the pancreatic calculi, viz., calcium carbonate, and (4) cholic acid, a steroidal hormone are presented. The effect of various organic and inorganic ions, trace elements, and extracts from cereals, herbs, and fruits on the crystallization of major urinary stone and gallstone constituents are described. In addition, tables of gel-grown organic and inorganic crystals are provided.

Narayana Kalkura, S.; Natarajan, Subramanian

455

Detection of protein-protein interactions and a group of immunoglobulin G-associated minor proteins in human plasma by nondenaturing and denaturing two-dimensional gel electrophoresis.  

PubMed

The dissociation of noncovalently associated protein-protein complexes in human plasma was examined by comparing two-dimensional gel electrophoresis (2-DE) patterns obtained in two different electrophoretic conditions. A type I 2-DE pattern was obtained running nondenaturing isoelectric focusing (IEF) followed by nondenaturing gel electrophoresis and a type II 2-DE pattern was nondenaturing IEF followed by sodium dodecyl sulfate gel electrophoresis. Micro-sized gels (internal diameter(id) 1.3 x 35 mm polyacrylamide IEF gels and 38 x 38 x 1 mm polyacryamide slab gels) were used to follow the dissociation processes of major plasma proteins. Larger gel sizes (id 3.4 x 160 mm agarose IEF gels and 160 x 120 x 2.8 mm polyacrylamide slab gels) were used to detect minor plasma proteins dissociated from major proteins. About 110 spots, which have not been detected on type I (nondenaturing) 2-D gels, newly appeared on type II large-sized 2-D gels at molecular masses smaller than 67 kDa. Some of these spots had been analyzed and identified, but about 70 minor spots (isoelectric point 5.5-7.5 and relative molecular mass 8-45 kDa) were detected for the first time by applying large volumes of human plasma samples to the large type II 2-D gels. These minor spots could be concentrated on type II 2-D gels by enriching the immunoglobulin G (IgG) fraction under nondenaturing conditions, and they disappeared when IgG was removed from the fraction. These results strongly suggest that many of the minor spots newly detected were bound to IgG in physiological conditions. PMID:12833506

Manabe, Takashi; Yamaguchi, Nao; Mukai, Jun; Hamada, Osamu; Tani, Osamu

2003-06-01

456

CONFORMANCE IMPROVEMENT USING GELS  

SciTech Connect

This technical progress report describes work performed from June 20 through December 19, 2001, for the project, ''Conformance Improvement Using Gels''. Interest has increased in some new polymeric products that purport to substantially reduce permeability to water while causing minimum permeability reduction to oil. In view of this interest, we are currently studying BJ's Aqua Con. Results from six corefloods revealed that the Aqua Con gelant consistently reduced permeability to water more than that to oil. However, the magnitude of the disproportionate permeability reduction varied significantly for the various experiments. Thus, as with most materials tested to date, the issue of reproducibility and control of the disproportionate permeability remains to be resolved. Concern exists about the ability of gels to resist washout after placement in fractures. We examined whether a width constriction in the middle of a fracture would cause different gel washout behavior upstream versus downstream of the constriction. Tests were performed using a formed Cr(III)-acetate-HPAM gel in a 48-in.-long fracture with three sections of equal length, but with widths of 0.08-, 0.02-, and 0.08-in., respectively. The pressure gradients during gel extrusion (i.e., placement) were similar in the two 0.08-in.-wide fracture sections, even though they were separated by a 0.02-in.-wide fracture section. The constriction associated with the middle fracture section may have inhibited gel washout during the first pulse of brine injection after gel placement. However, during subsequent phases of brine injection, the constriction did not inhibit washout in the upstream fracture section any more than in the downstream section.

Randall S. Seright

2002-02-28