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1

Rapid detection of adulterations of fruit juices, lemonades etc. by electrophoresis on cellulose acetate membranes  

Microsoft Academic Search

Zusammenfassung Es wurde eine Schnellmethode zum Nachweis der Verfälschungen von Fruchtsäften und Getränken mittels Elektrophorese und Vergleich der Hauptaminosäurebanden (Cellulose-acetat-Membran; Pufferlösung aus 0,25n Essigsäure\\/0,65n Ameisensäure; Anfärbung mit Ninhydrin) entwickelt. Die untere Nachweisgrenze beträgt etwa 0,01 mg Aminosäure\\/ml.

Wilhelm F. van Gils; Johannes A. van den Bergh

1974-01-01

2

New Analytical Method for Cellulose Acetate Electrophoresis Using Terahertz Imaging  

NASA Astrophysics Data System (ADS)

We propose a new method of analyzing the results of cellulose acetate electrophoresis by terahertz imaging. To verify accuracy of terahertz imaging of cellulose acetate electrophoresis, we compared the images obtained by terahertz imaging with those obtained by the one-side staining method. To obtain accurate information about the distribution of medical molecules in cellulose acetate by terahertz imaging, owing to the low concentration, a suitable imaging spatial resolution is required to estimate the distribution accurately in the cellulose acetate membrane. Here, we have improved the spatial resolution by reducing the absorption of the diffusion of the terahertz signal from the sample surface. Using the terahertz imaging system, we obtained terahertz images of the cellulose acetate with a glycine sensitivity of 3.71 ?g/mm2 and an l-methionine sensitivity of 6.22 ?g/mm2. Comparison of the terahertz and staining images showed that the new imaging method using the terahertz imaging system has a good possibility for cellulose acetate membrane electrophoresis analysis even for relatively low-concentration electrophoresis.

Zhang, Hong Bing; Mitobe, Kazutaka; Suzuki, Masafumi; Yoshimura, Noboru

2009-06-01

3

A quantitative method for blood lipoproteins using cellulose acetate electrophoresis  

PubMed Central

A rapid, inexpensive, and quantitative method is described for obtaining the levels of plasma very low, low, and high density lipoproteins using cellulose acetate electrophoresis and lipid assays without prior separation by ultracentrifuge or other techniques. It involves separation of the lipoproteins by cellulose acetate electrophoresis, followed by their identification with the ozone-Schiff reaction. The total lipoprotein concentration is estimated from the total plasma phospholipid, and the percentage of each component obtained by densitometric analysis of the stained electrophoretograms, using reflected light. For samples with a raised level of very low density lipoprotein, plasma triglyceride analysis is also required. The results obtained by the cellulose acetate electrophoresis method are in good agreement with those by the analytical ultracentrifuge and the preparative ultracentrifuge with refractometry. The theoretical assumptions on which the method is based have been shown to be valid. Images

Magnani, H. N.; Howard, A. N.

1971-01-01

4

Comments on the determination of isoenzyme polymorphism (ADA, AK, 6-PGD, PGM) by cellulose acetate electrophoresis  

Microsoft Academic Search

Summary The paper highlights certain peculiarities of isoenzyme polymorphism as determined by cellulose acetate electrophoresis, as compared to other supporting media at different pH levels and concentrations of the buffer.

H.-H. Sonneborn

1972-01-01

5

Cellulose Acetate Electrophoresis of Cerebrospinal Fluid Proteins with Normal Values of 135 Persons.  

National Technical Information Service (NTIS)

A study on cellulose acetate electrophoresis of cerebrospinal fluid (CSF) proteins is reported. Two methods are used for concentration, acetone precipitation and sephadex dialysis with slight modifications. They are both considered to be clinically valuab...

1980-01-01

6

Dehydration of acetic acid by pervaporation with charged membranes  

Microsoft Academic Search

Modified Nafion membranes were prepared by charging Nafion 117 membrane with different long-chained counter ions and used for pervaporation of acetic acid–water mixture. It was observed, that the selectivity of Nafion membrane was enhanced by charging with long-chained counter ions. However, it led to a decrease in permeate flux because of decreasing solubility and diffusivity of the membranes. The results

Samuel P. Kusumocahyo; Masao Sudoh

1999-01-01

7

Membranes of the adrenal medulla. Behaviour of insoluble proteins of chromaffin granules on gel electrophoresis  

PubMed Central

Washed membranes of bovine adrenal chromaffin granules contained most of the cholesterol and phospholipids of the particle and 22% of the total protein. The protein/lipid ratio was about 0.45 (w/w). Dopamine(3,4-dihydroxyphenethylamine)?-hydroxylase, Mg2+-activated nucleoside triphosphatase and cytochrome b-559 activities were present in the membrane. ATP was the best substrate for the nucleoside triphosphatase, whose pH optimum was 6.4, Km 7×10?4m and Vmax. 1.8?mol/h per mg of protein. Treatment of the membranes with various detergents caused a preferential solubilization of protein compared with lipids. Membranes dissolved in sodium dodecyl sulphate or phenol–acetic acid–urea were subjected to polyacrylamide-gel electrophoresis at alkaline and acid pH respectively. The electrophoretic patterns given by the proteins of the chromaffin granule membrane were distinct from those given by the chromogranins, and from those given by mitochondrial and microsomal membrane proteins. ImagesPLATE 1

Winkler, H.; Hortnagl, Heide; Hortnagl, H.; Smith, A. D.

1970-01-01

8

Modified alginate composite membranes for the dehydration of acetic acid  

Microsoft Academic Search

Alginate composite membranes cross-linked with 1,6-hexanediamine (HDM) or poly(vinyl alcohol) (PVA) were prepared by casting an aqueous solution of alginate and HDM or PVA on a hydrolyzed microporous polyacrylonitrile (PAN) membrane and characterized by pervaporation separation of acetic acid\\/water mixtures. The influence of hydrolysis of PAN support layer and HDM content in dense layer on separation performance of the composite

Xin-Ping Wang

2000-01-01

9

Separation of acetic acid-water mixtures by pervaporation through silicalite membrane  

Microsoft Academic Search

Polycrystalline silicalite membranes were prepared on two kinds of porous supports by hydrothermal synthesis. The pervaporation performance of the silicalite membrane obtained was investigated using an acetic acid-water mixture as a feed. The silicalite membrane on the sintered stainless steel support selectively permeates acetic acid in the concentration of the feed acetic acid in the region of 5 to 40

Tsuneji Sano; Shigeyuki Ejiri; Kiyoshi Yamada; Yusuke Kawakami; Hiroshi Yanagishita

1997-01-01

10

The Use of Polymeric Gels to Reduce Compaction in Cellulose Acetate Reverse Osmosis Membranes.  

National Technical Information Service (NTIS)

Polymeric gels were synthesized by crosslinking cellulose acetate in emulsion and solution reactions. These gels were used to replace a portion of the linear cellulose acetate in a standard Manjikian-type asymmetric membrane, with the aim of reducing long...

S. L. Rosen C. Irani L. Baayens

1972-01-01

11

The Effects of Porous and Solid Fillers on the Permeability of Cellulose Acetate Membranes.  

National Technical Information Service (NTIS)

Several types of filled cellulose acetate membranes were prepared to determine the effect of filler properties and polymer properties on permeability of the composite materials. Casting procedures were chosen to give a dense cellulose acetate phase and a ...

P. Harriott J. Wu F. Klunker

1973-01-01

12

Pervaporation of acetic acid\\/water mixtures through carbon molecular sieve-filled PDMS membranes  

Microsoft Academic Search

The pervaporation process for acetic\\/water has been investigated with carbon molecular sieve (CMS)-filled polydimethylsiloxane (PDMS) membranes. The effects of feed temperature, feed acetic acid concentration and CMS content on the performance of the membranes have been studied. It is found that the addition of CMS can improve pervaporation behavior of PDMS membranes to some extent and greatly increases the strength

Lei Li; Zeyi Xiao; Zhibing Zhang; Shujuan Tan

2004-01-01

13

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

14

Antimicrobial membrane cellulose acetate containing ionic liquid and metal nanoparticles.  

PubMed

Stable metallic Au(0), Ag(0) and Pt(0) nanoparticle-containing membrane films (20 microm thickness) were obtained by combining irregularly shaped nanoparticles of monomodal size distributions (11 +/- 1.5 nm Au(0), 8.9 +/- 2.1 nm Ag(0) and 2.8 +/- 0.4 nm Pt(0)) in the ionic liquid (IL) 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMI x (NTf)2) with a syrup of cellulose acetate (CA) in acetone. The presence of small and stable Au(0), Ag(0) or Pt(0) nanoparticles induced an augmentation in the CA/IL film surface areas. The addition of the IL to the membrane resulted in an increase of its elasticity and a decrease in its tenacity and toughness, whereas its stress at break was not influenced. High antimicrobial activity was observed in membranes containing Au(0), Ag(0) and Pt(0) metal concentrations as low as 1 mg of metal per 5 g of CA. The CA/IL/nanoparticle combination enhanced the activity and durability of the metal nanoparticles and provided greater antimicrobial activity against E. coli and S. aureus bacteria. PMID:21770152

Scheeren, Carla W; Hermes, Vanessa; Bianchi, Otávio; Hertz, Plinho F; Dias, Silvio L P; Dupont, Jairton

2011-06-01

15

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

16

A Non-Denaturing Gel Electrophoresis System for the Purification of Membrane Bound Proteins  

Microsoft Academic Search

A new method is described for the purification of a membrane bound glycoprotein, the kappa opioid receptor from human placental tissue. The method uses preparative slab-gel electrophoresis in the presence of the non-denaturing detergent CHAPS. A linear relationship between log molecular weight and SDS PAGE electrophoretic mobility of known molecular weight markers, in the presence of CHAPS, is observed. Using

Anna G. Cavinato; Robert M. Macleod; Mahmoud S. Ahmed

1988-01-01

17

Capillary blotting of glycosaminoglycans on nitrocellulose membranes after agarose-gel electrophoresis separation.  

PubMed

A method for the blotting and immobilizing of several nonsulfated and sulfated complex polysaccharides on membranes made hydrophilic and positively charged by cationic detergent after their separation by conventional agarose gel electrophoresis is illustrated. This new approach to the study of glycosaminoglycans (GAGs) utilizes the capacity of agarose gel electrophoresis to separate single species of polysaccharides from mixtures and the membrane technology for further preparative and analytical uses.Nitrocellulose membranes are derivatized with the cationic detergent cetylpyridinium chloride and mixtures of GAGs are capillary blotted after their separation in agarose gel electrophoresis. Single purified species of variously sulfated polysaccharides are transferred on derivatized membranes with an efficiency of 100% and stained with alcian blue (irreversible staining) and toluidine blue (reversible staining). This enables a lower amount limit of detection of 0.1 microg. Nonsulfated polyanions, for example hyaluronic acid, may also be transferred to membranes with a limit of detection of approximately 0.1-0.5 microg after irreversible or reversible staining. The membranes may be stained with reversible staining and the same lanes are used for immunological detection or other applications. PMID:19378049

Volpi, Nicola; Maccari, Francesca

2009-01-01

18

Role of membrane surface morphology in colloidal fouling of cellulose acetate and composite aromatic polyamide reverse osmosis membranes  

Microsoft Academic Search

Laboratory-scale colloidal fouling tests, comparing the fouling behavior of cellulose acetate and aromatic polyamide thin-film composite reverse osmosis (RO) membranes, are reported. Fouling of both membranes was studied at identical initial permeation rates so that the effect of the transverse hydrodynamic force (permeation drag) on the fouling of both membranes is comparable. Results showed a significantly higher fouling rate for

Menachem Elimelech; Xiaohua Zhu; Amy E. Childress; Seungkwan Hong

1997-01-01

19

Electrophoresis of concanavalin A receptors along embryonic muscle cell membrane  

Microsoft Academic Search

Fluorescent concanavalin A (con A)-labelling showed that an electric field of 4 V cm-1 grossly redistributed con A receptors along the plasma membranes of living muscle cells within 4 h. This field produced a voltage drop of 12 mV across these 30 µm-wide cells. The movement of receptors was independent of cell metabolism and seemed to be electrophoretic in nature.

Mu-Ming Poo; Kenneth R. Robinson

1977-01-01

20

Chelation and permeation of heavy metals using affinity membranes from cellulose acetate–chitosan blends  

Microsoft Academic Search

Affinity membranes have attracted the attention of membrane researchers especially in the field of wastewater treatment specifically in removing heavy metals by chelation from aqueous solutions. In the present work, several membranes are made from either cellulose di-acetate (CA) or CA together with chitosan (CS) solutions, the CS prepared in our lab from shrimp shells or from readymade shrimp or

M. M. Naim; H. E. M. Abdel Razek

2012-01-01

21

Characteristics of Porous Cellulose Acetate Membranes for the Separation of Some Inorganic Salts in Aqueous Solution.  

National Technical Information Service (NTIS)

Experimental results are presented to illustrate the effect of operating variables on the separation and flow characteristics of porous cellulose acetate membranes. The results are discussed from the point of view of the preferential sorption and capillar...

S. Sourirajan

1964-01-01

22

Specification, Selectivity, and Performance of Porous Cellulose Acetate Membranes in Reverse Osmosis.  

National Technical Information Service (NTIS)

The general specifications of the Loeb-Sourirajan type porous cellulose acetate membranes are given in terms of the pure water permeability constant, A, and the solute transport parameter for sodium chloride at different operating pressures. A scale of me...

J. P. Agrawal S. Sourirajan

1969-01-01

23

Study of Methods to Retard Compaction of Cellulose Acetate Membranes in Reverse Osmosis Desalination.  

National Technical Information Service (NTIS)

Cellulose acetate can be effectively crosslinked with hexamethoxymethyl melamine, acetyl acetonate titanium chelate, sodium dichromate, or lead oxide to prevent desalination membrane compaction. Only pigment reinforcement was promising in preventing the c...

B. Baum S. A. Margosiak W. H. Holley

1969-01-01

24

A Study of Polydimethylsiloxane\\/Aromatic Polyamide Laminated Membranes for Separation of Acetic Acid\\/Water Mixtures by Pervaporation Process  

Microsoft Academic Search

Separation of acetic acid\\/water mixtures by pervaporation was attempted over a range of compositions using polydimethylsiloxane (PDMS), aromatic polyamide (PA), and laminated polydimethylsiloxane-aromatic polyamide membranes. PDMS membranes are hydrophobic and acetic acid selective, whereas PA membranes are hydrophilic and water selective. When PDMS and PA membranes were laminated, with PDMS on the top side and in contact with the feed,

SHENGZHI DENG; S. SOURIRAJAN; T. MATSUURA

1994-01-01

25

Enhanced detergent extraction for analysis of membrane proteomes by two-dimensional gel electrophoresis  

PubMed Central

Background The analysis of hydrophobic membrane proteins by two-dimensional gel electrophoresis has long been hampered by the concept of inherent difficulty due to solubility issues. We have optimized extraction protocols by varying the detergent composition of the solubilization buffer with a variety of commercially available non-ionic and zwitterionic detergents and detergent-like phospholipids. Results After initial analyses by one-dimensional SDS-PAGE, quantitative two-dimensional analyses of human erythrocyte membranes, mouse liver membranes, and mouse brain membranes, extracted with buffers that included the zwitterionic detergent MEGA 10 (decanoyl-N-methylglucamide) and the zwitterionic lipid LPC (1-lauroyl lysophosphatidylcholine), showed selective improvement over extraction with the common 2-DE detergent CHAPS (3 [(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate). Mixtures of the three detergents showed additive improvements in spot number, density, and resolution. Substantial improvements in the analysis of a brain membrane proteome were observed. Conclusion This study demonstrates that an optimized detergent mix, coupled with rigorous sample handling and electrophoretic protocols, enables simple and effective analysis of membrane proteomes using two-dimensional electrophoresis.

Churchward, Matthew A; Butt, R Hussain; Lang, John C; Hsu, Kimberly K; Coorssen, Jens R

2005-01-01

26

Inability of Microorganisms To Degrade Cellulose Acetate Reverse-Osmosis Membranes  

PubMed Central

Operational cellulose acetate reverse-osmosis membranes were examined for evidence of biological degradation. Numerous fungi and bacteria were isolated by direct and enrichment techniques. When tested, most of the fungi were active cellulose degraders, but none of the bacteria were. Neither fungi nor bacteria were able to degrade cellulose acetate membrane in vitro, although many fungi were able to degrade cellulose acetate membrane after it had been deacetylated. Organisms did not significantly degrade powdered cellulose acetate in pure or mixed cultures as measured by reduction in acetyl content or intrinsic viscosity or production of reducing sugars. Organisms did not affect the performance of cellulose triacetate fibers when incubated with them. The inability of the organisms to degrade cellulose acetate was attributed to the high degree of acetate substitution of the cellulose polymer. The rate of salt rejection decline was strongly correlated with chlorination of feed water and inversely with densities of microorganisms. These data suggest that microbial degradation of operational cellulose acetate reverse-osmosis membranes is unlikely.

Ho, Leighton C. W.; Martin, David D.; Lindemann, William C.

1983-01-01

27

Direct coupling of supported liquid membranes to capillary electrophoresis for analysis of complex samples: a tutorial.  

PubMed

This tutorial provides an overview of direct coupling of extraction techniques based on supported liquid membranes (SLMs) to capillary electrophoresis (CE) for treatment and subsequent analysis of complex samples. Pros and cons of using each of the described instrumental arrangement are addressed and where relevant, comments with personal experience of the authors are presented. Solid porous membrane based extraction techniques coupled directly to CE are also presented in this tutorial and a comprehensive discussion is included on their instrumental set-ups and their possible adaptation for use with SLMs. PMID:23830417

Kubá?, Pavel; Bo?ek, Petr

2013-05-15

28

Effect of conjugated linoleic acid immobilization on the hemocompatibility of cellulose acetate membrane  

Microsoft Academic Search

Conjugated linoleic acid (CLA) was covalently immobilized onto cellulose acetate (CA) membranes. The effects of CLA immobilization on the blood coagulation, platelet aggregation, and oxidative stress were evaluated using human blood. The resulting CLA grafting CA membranes were characterized with X-ray photoelectronic spectroscopy (XPS). The complete blood count (CBC) and coagulation time (CT) was evaluated in vitro for the hemocompatibility.

F.-C. Kung; M.-C. Yang

2006-01-01

29

Performance of a composite membrane bioreactor for the removal of ethyl acetate from waste air.  

PubMed

Ethyl acetate removal from an air stream was carried out by using a flat composite membrane bioreactor. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 0.3 ?m supported in a porous polyacrylonitrile layer (50 ?m). The membrane bioreactor (MBR) was operated during 3 months, and a maximum elimination capacity of 225 g m?³ h?¹ at an empty bed residence time of 60s was observed. Removal efficiencies higher than 95% were obtained for inlet loads lower than 200 g m?³ h?¹ and empty bed residence times as short as 15 s. The estimated yield coefficient, determined from the carbon dioxide production, resulted in 0.82 g dry biomass synthesized per gram of ethyl acetate degraded. No data of ethyl acetate treatment in MBR have been found in the literature, but the results illustrate that membrane bioreactors can potentially be a good option for its treatment. PMID:21763129

Álvarez-Hornos, F J; Volckaert, D; Heynderickx, P M; Van Langenhove, H

2011-06-23

30

Novel cellulose acetate membrane blended with phospholipid polymer for hemocompatible filtration system  

Microsoft Academic Search

To improve the blood compatibility of cellulose acetate (CA) membranes for hemofiltration, a novel CA membrane blended with 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer was designed for a hemocompatible filtration system. The MPC copolymer (PMB30) was synthesized from MPC and n-butyl methacrylate. The polymer solution for making the membrane was prepared from a solvent mixture composed of N,N-dimethylformamide, acetone, and 2-propanol. The

Sang Ho Ye; Junji Watanabe; Yasuhiko Iwasaki; Kazuhiko Ishihara

2002-01-01

31

Acetate-induced apoptosis in colorectal carcinoma cells involves lysosomal membrane permeabilization and cathepsin D release  

PubMed Central

Colorectal carcinoma (CRC) is one of the most common causes of cancer-related mortality. Short-chain fatty acids secreted by dietary propionibacteria from the intestine, such as acetate, induce apoptosis in CRC cells and may therefore be relevant in CRC prevention and therapy. We previously reported that acetic acid-induced apoptosis in Saccharomyces cerevisiae cells involves partial vacuole permeabilization and release of Pep4p, the yeast cathepsin D (CatD), which has a protective role in this process. In cancer cells, lysosomes have emerged as key players in apoptosis through selective lysosomal membrane permeabilization (LMP) and release of cathepsins. However, the role of CatD in CRC survival is controversial and has not been assessed in response to acetate. We aimed to ascertain whether LMP and CatD are involved in acetate-induced apoptosis in CRC cells. We showed that acetate per se inhibits proliferation and induces apoptosis. More importantly, we uncovered that acetate triggers LMP and CatD release to the cytosol. Pepstatin A (a CatD inhibitor) but not E64d (a cathepsin B and L inhibitor) increased acetate-induced apoptosis of CRC cells, suggesting that CatD has a protective role in this process. Our data indicate that acetate induces LMP and subsequent release of CatD in CRC cells undergoing apoptosis, and suggest exploiting novel strategies using acetate as a prevention/therapeutic agent in CRC, through simultaneous treatment with CatD inhibitors.

Marques, C; Oliveira, C S F; Alves, S; Chaves, S R; Coutinho, O P; Corte-Real, M; Preto, A

2013-01-01

32

Pervaporation separation of ethyl acetate–ethanol binary mixtures using polydimethylsiloxane membranes  

Microsoft Academic Search

Pervaporation separation of azeotrope forming ethyl acetate–ethanol mixtures was investigated by using a selfmade polydimethylsiloxane (PDMS) membrane. Sorption, desorption and pervaporation experiments for ethyl acetate–ethanol mixture with different concentrations were conducted at 30, 40 and 50°C. The effect of process parameters such as feed concentration and temperature on flux and selectivity is discussed. Equilibrium curves are determined by vapor–liquid equilibrium

A. Hasano?lu; Y. Salt; S. Kele?er; S. Özkan; S. Dinçer

2005-01-01

33

Enhanced separation of membranes during free flow zonal electrophoresis in plants.  

PubMed

Free flow zonal electrophoresis (FFZE) is a versatile technique that allows for the separation of cells, organelles, membranes, and proteins based on net surface charge during laminar flow through a thin aqueous layer. We have been optimizing the FFZE technique to enhance separation of plant vacuolar membranes (tonoplast) from other endomembranes to pursue a directed proteomics approach to identify novel tonoplast transporters. Addition of ATP to a mixture of endomembranes selectively enhanced electrophoretic mobility of acidic vesicular compartments during FFZE toward the positive electrode. This has been attributed to activation of the V-ATPase generating a more negative membrane potential outside the vesicles, resulting in enhanced migration of acidic vesicles, including tonoplast, to the anode (Morré, D. J.; Lawrence, J.; Safranski, K.; Hammond, T.; Morré, D. M. J. Chromatogr., A 1994, 668, 201-213). We confirm that ATP does induce a redistribution of membranes during FFZE of microsomal membranes isolated from several plant species, including Arabidopsis thaliana, Thellungiella halophila, Mesembryanthemum crystallinum, and Ananas comosus. However, we demonstrate, using V-ATPase-specific inhibitors, nonhydrolyzable ATP analogs, and ionophores to dissipate membrane potential, that the ATP-dependent migrational shift of membranes under FFZE is not due to activation of the V-ATPase. Addition of EDTA to chelate Mg2+, leading to the production of the tetravalent anionic form of ATP, resulted in a further enhancement of membrane migration toward the anode, and manipulation of cell surface charge by addition of polycations also influenced the ATP-dependent migration of membranes. We propose that ATP enhances the mobility of endomembranes by screening positive surface charges on the membrane surface. PMID:17566980

Barkla, Bronwyn J; Vera-Estrella, Rosario; Pantoja, Omar

2007-06-13

34

Non-denaturing gel electrophoresis system for the purification of membrane bound proteins  

SciTech Connect

A new method is described for the purification of a membrane bound glycoprotein, the kappa opioid receptor from human placental tissue. The method uses preparative slab-gel electrophoresis in the presence of the non-denaturing detergent CHAPS. A linear relationship between log molecular weight and SDS PAGE electrophoretic mobility of known molecular weight markers, in the presence of CHAPS, is observed. Using this method, we were able partially to purify an /sup 3/H-etorphine binding glycoprotein, from placental villus tissue, with an apparent molecular weight range of 60-70,000. The iodinated glycoprotein migrates in SDS PAGE with an apparent molecular weight of 63,000. This method may be useful for the isolation of membrane bound proteins, especially when an affinity ligand is not available.

Cavinato, A.G.; Macleod, R.M.; Ahmed, M.S.

1988-01-01

35

Development of polyion complex membranes based on cellulose acetate modified by oxygen plasma treatment for pervaporation  

Microsoft Academic Search

Cellulose acetate (CA) membrane was modified with ultra-thin polyion complex (PIC) layers, and the pervaporation performance for water–ethanol mixture was investigated. Introduction of oxygen-containing anionic groups onto the surface of the CA membrane was attempted by the oxygen plasma treatment, and was confirmed by the electron spectroscopy for chemical analysis (ESCA). The formation of an ultra-thin PIC layer on the

Samuel P Kusumocahyo; Toshiyuki Kanamori; Takashi Iwatsubo; Kimio Sumaru; Toshio Shinbo

2002-01-01

36

Pentose oxidation by acetic Acid bacteria led to a finding of membrane-bound purine nucleosidase.  

PubMed

D-Ribose and 2-deoxy-D-ribose were oxidized to 4-keto-D-ribonate and 2-deoxy-4-keto-D-ribonate respectively by oxidative fermentation, and the chemical structures of the oxidation products were confirmed to be as expected. Both pentoses are important sugar components of nucleic acids. When examined, purine nucleosidase activity predominated in the membrane fraction of acetic acid bacteria. This is perhaps the first finding of membrane-bound purine nucleosidase. PMID:23649247

Adachi, Osao; Hours, Roque A; Akakabe, Yoshihiko; Shinagawa, Emiko; Ano, Yoshitaka; Yakushi, Toshiharu; Matsushita, Kazunobu

2013-05-07

37

Pervaporation of acetic acid\\/water mixtures through silicalite filled polydimethylsiloxane membranes  

Microsoft Academic Search

The preferential pervaporation of acetic acid over water is achieved with silicalite filled polydimethylsiloxane (PDMS) membranes. The effect of silicalite addition is not positive at the feed temperature of 25°C, but improves with increasing feed temperature. At a feed temperature of 45°C, silicalite addition enhances not only the separation factor but also the permeation flux of the pervaporation. This improvement

Shih-Yuan Lu; Chung-Ping Chiu; Hsiang-Yuan Huang

2000-01-01

38

Western blotting using microchip electrophoresis interfaced to a protein capture membrane.  

PubMed

Western blotting is a commonly used assay for proteins. Despite the utility of the method, it is also characterized by long analysis times, manual operation, and lack of established miniaturized counterpart. We report a new way to Western blot that addresses these limitations. In the method, sodium dodecyl sulfate (SDS)-protein complexes are separated by sieving electrophoresis in a microfluidic device or chip. The chip is interfaced to a moving membrane so that proteins are captured in discrete zones as they migrate from the chip. Separations of SDS-protein complexes in the molecular weight range of 11-155 kDa were completed in 2 min with 4 × 10(4) theoretical plates at 460 V/cm. Migration time and peak area relative standard deviations were 3-6% and 0.2%, respectively. Detection limit for actin was 0.7 nM. Assays for actin, AMP-kinase, carbonic anhydrase, and lysozyme are shown to demonstrate versatility of the method. Total analysis time including immunoassay was 22-32 min for a single sample. Because processing membrane for immunoassay is the slow step of the assay, sequential injections from different reservoirs on the chip and capture in different tracks on the same membrane allow increased throughput. As a demonstration, 9 injections were collected on one membrane and analyzed in 43 min (~5 min/sample). Further improvements in throughput are possible with more reservoirs or parallel channels. PMID:23672369

Jin, Shi; Anderson, Gwendolyn J; Kennedy, Robert T

2013-05-28

39

Enzymatic activation of cellulose acetate membrane for reducing of protein fouling.  

PubMed

In this study, the surface of cellulose acetate (CA) ultrafiltration membrane was activated with serine protease (Savinase) enzyme to reduce protein fouling. Enzyme molecules were covalently immobilized with glutaraldehyde (cross-linking agent) onto the surface of CA membranes. The membrane activation was verified using filtration experiments and morphological analysis. Scanning electron microscopy (SEM) images and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy of the activated membrane when compared with raw membrane were confirmed that the enzyme was immobilized onto the membrane surface. The immobilization efficiencies changed from 13.2 to 41.2% according to the enzyme ratios from 2.5 to 10.0 mg/mL. However, the permeability values decreased from 232±6 to 121±4 L/m(2) h bar with increasing enzyme concentration from 2.5 to 10.0 mg/mL. In fouling experiments, bovine serum albumin (BSA) was used as the protein model solution and activated sludge was used as the model biological sludge. Enzyme-activated membranes exhibited good filtration performances and protein rejection efficiencies were compared with raw CA membrane. Also the relative flux reduction (RFR) ratios of membranes were calculated as 97% and 88% for raw CA and enzyme-activated membranes (5 mg/mL savinase), respectively. The membrane activated with Savinase enzyme could be proposed as a surface treatment method before filtration to mitigate protein fouling. PMID:22218336

Koseoglu-Imer, Derya Y; Dizge, Nadir; Koyuncu, Ismail

2011-12-20

40

Study of polydimethylsiloxane/aromatic polyamide laminated membranes for separation of acetic acid/water mixtures by pervaporation process  

SciTech Connect

Separation of acetic acid/water mixtures by pervaporation was attempted over a range of compositions using polydimethylsiloxane (PDMS), aromatic polyamide (PA), and laminated polydimethylsiloxane-aromatic polyamide membranes. PDMS membranes are hydrophobic and acetic acid selective, whereas PA membranes are hydrophilic and water selective. When PDMS and PA membranes were laminated, with PDMS on the top side and in contact with the feed, water selectivity of the bottom PA membrane was intensified. On the other hand, when the PA membrane was on the top side and in contact with the feed, the selectivity was lowered. 10 refs., 4 figs.

Deng, S.; Sourirajan, S.; Matsuura, T. (Univ. of Ottawa (Canada))

1994-06-01

41

High resolution two-dimensional gel electrophoresis of human erythrocyte membrane proteins.  

PubMed Central

Three different two-dimensional (2-D) gel electrophoretic techniques have been modified to provide high resolution of human erythrocyte membrane proteins. The resulting gels were referenced to the established one-dimensional (1-D) sodium dodecylsulfate (SDS) gel electrophoretic profile, and the effects of endogenous proteolysis and cytosolic contamination were studied. It is concluded that in vitro proteolysis and cytosolic contamination do not contribute significantly to the patterns observed on the 2-D gels, under the conditions used for erythrocyte ghost preparation. The procedures require only small quantities of blood; as many as twenty 2-D gel profiles can be obtained from 5 ml of blood. The combination of nonequilibrium isoelectric focusing (IEF) in the first dimension, SDS electrophoresis in the second dimension, and very sensitive silver staining techniques resolves more than 250 individual protein spots. This appears to be the most useful single procedure for the analysis of red cell membrane proteins. Membrane protein profiles from patients with Duchenne muscular dystrophy, Wernicke-Korsakoff syndrome, and acanthocytosis with degeneration of the basal ganglia were compared with normal controls. The patterns for Duchenne muscular dystrophy and Wernicke-Korsakoff syndrome were not different from normal patterns. The pattern for the patient with acanthocytosis and degeneration of the basal ganglia consistently showed a high level for one protein in the 100,000 mol. wt. range. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

Copeland, B R; Todd, S A; Furlong, C E

1982-01-01

42

Transport of lactate and acetate through the energized cytoplasmic membrane of Escherichia coli  

SciTech Connect

Escherichia coli produces lactate and acetate in significant amounts during both aerobic and anaerobic glycolysis. A model describing the mechanism of protein-mediated lactate transport has previously been proposed. A simple theoretical analysis here indicates that the proposed model would drain cellular energy resources by catalytically dissipating the proton-motive force. An experimental analysis of lactate and acetate transport employs nuclear magnetic resonance (NMR) spectroscopy to measure the relative concentrations of these end products on the two sides of the cytoplasmic membrane of anaerobically glycolyzing cells. Comparison of measured concentration ratios of those expected at equilibrium for various transport modes indicates that acetate is a classical uncoupling agent, permeating the membrane at comparable rates in the dissociated and undissociated forms. The lactate concentration ratio changes markedly after an initial period of sustained glycolysis. This change is most readily explained as resulting from a lactate transport system that responds to an indicator of glycolytic activity. The data further indicate that lactate permeates the membrane in both dissociated and undissociated forms. Both acids, then, are capable of catalytically dissipating the proton-motive force.

Axe, D.D.; Bailey, J.E. [California Inst. of Technology, Pasadena, CA (United States). Div. of Chemistry and Chemical Engineering

1995-07-05

43

Two-dimensional gel electrophoresis and immunoblotting of Campylobacter outer membrane proteins.  

PubMed Central

We characterized outer membrane proteins (OMPs) from selected Campylobacter jejuni, C. coli, and C. fetus strains by two-dimensional gel electrophoresis (2DGE), using isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and by immunoblotting with immune rabbit serum. The flagellar band with a molecular mass of 63 kilodaltons (kDa) demonstrated previously by one-dimensional SDS-PAGE was shown by 2DGE to consist of one or several charge trains, depending upon the species, strain, and type of preparation studied; each of the individual peptides was found to be antigenic by immunoblotting. In contrast, in all of the strains studied, the major OMP (43 to 44 kDa) of C.jejuni and C. coli consisted of a single isomeric form which was weakly immunogenic. Several minor proteins (29 to 31 kDa) were found to be strongly immunogenic by immunoblotting. C. fetus strains possessed two major OMPs of 45 to 47 kDa, each of which consisted of either a single isomer or a major isomer comprising at least 90% of the major OMP. Serum-resistant strains of C. fetus possessed an acid-labile 100-kDa glycoprotein (pI, 4.1) which was markedly diminished or absent in serum-sensitive strains. These 2DGE analyses provide information that is useful in taxonomic and epidemiologic studies and for the purification of surface antigens for the development of campylobacter vaccines and may also facilitate the identification of specific virulence factors. Images

Dunn, B E; Blaser, M J; Snyder, E L

1987-01-01

44

Effect of electro-chemical properties of chloride salts on their diffusional parameters in symmetrical cellulose acetate membranes  

Microsoft Academic Search

A relation was obtained between electro-chemical properties of alkali, alkali earth and aluminium chlorides (LiCl, NaCl, KCl, RbCl, CsCl, MgCl2, CaCl2, AlCl3) and the distribution coefficient K and the overall diffusion coefficients D in symmetrical cellulose acetate membranes. Symmetrical cellulose acetate membranes were cast to have a wider range of water content, 15–30%. K and D were measured by the

Haruhiko Ohya; Svetlana I Semenova; Toshinori Fujimoto; Jun Ogihara; Shinichi Fukaya; Kousuke Mori; Masahiko Aihara; Youichi Negishi

2001-01-01

45

Osmotic water transport through cellulose acetate membranes produced from a latex system.  

PubMed

The advisability of a progressive curtailment of organic solvent film coating offers an incentive to develop latex systems. Here, the use of aqueous colloidal dispersions of cellulose acetate, plasticized with water-soluble additives, is proposed as an alternative way to obtain cellulose acetate membranes either by casting or spraying. The osmotic water permeability of both kinds of films was measured, as well as their loss of leachable materials and degree of swelling in a saturated solution of potassium chloride. The permeabilities varied over a wide range depending on the physicochemical properties of the plasticizer and its initial concentration in the latex, and on the conditions for coating (temperature, rate of spraying, and drying duration). High boiling point plasticizers gave more permeable films. Films prepared by casting were found to be sensitive to their sodium dodecyl sulfate content. PMID:3625490

Bindschaedler, C; Gurny, R; Doelker, E

1987-06-01

46

Kolbe electrolysis of acetic acid in a polymer electrolyte membrane reactor  

SciTech Connect

A polymer electrolyte membrane (PEM) reactor is described for use in Kolbe electrolysis: the anodic oxidation of an alkyl carboxylic acid with subsequent decarboxylation and coupling to yield a dimer, 2RCOOH {r_arrow} R-R + 2CO{sub 2} + 2e{sup {minus}} + 2H{sup +}. Platinized Nafion 117 is the PEM and functions simultaneously as the electrolyte and separator. Results demonstrating the feasibility of Kolbe electrolysis in a PEM reactor are presented for the oxidation of gaseous acetic acid (in a nitrogen diluent) to ethane and carbon dioxide, with hydrogen evolution at the counter electrode. The investigation includes the following effects on current density, current efficiency, and product selectivity: acetic acid partial pressure (P{sub total} {approx} 1 atm), cell voltage and temperature, phase of the catholyte (liquid water or humidified nitrogen), and the procedure used to prepare the membrane-electrode assembly. Current densities from 0.06 to 0.4 A/cm{sup 2} with Kolbe current efficiencies of 10 to 90% were obtained for cell voltages ranging from 4 to 10 V. The best results were obtained using PEMs platinized by a nonequilibrium impregnation-reduction method; a 75% current efficiency at 0.3 A/cm{sup 1} with a cell voltage of 6 V were measured at the following reaction conditions: 42 C reactor, 58 mm Hg acetic acid (50 C acetic acid dew point), and 42 C liquid water to the cathode. These initial results are encouraging for Kolbe electrolysis in a PEM cell; additional work, however, is needed to determine if the PEM strategy may be employed using a liquid-phase reactant. In addition, optimal reaction conditions and downstream mass-transfer separation requirements remain to be determined, both of which are reactant specific.

Hicks, M.T.; Fedkiw, P.S. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering

1998-11-01

47

Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Polyetherimide, cellulose acetate and ethylcellulose  

SciTech Connect

The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with an ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.

Not Available

1986-01-01

48

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

49

A novel, post-column micro-membrane reactor for fluorescent analysis of protein in capillary electrophoresis.  

PubMed

Based on the semipermeability of hollow fiber membranes, a post-column membrane reactor was developed for capillary electrophoresis (CE)-laser induced fluorescence (LIF) analysis of proteins by using a hollow fiber membrane to connect the separation and detection capillaries. The membrane length between the separation and detection capillaries was 1 mm. Driven by the chemical potential difference between the separation buffer inside the membrane and the fluorescence derivatization solution outside the membrane, the derivatization reagent can be easily drawn into hollow fiber membrane to react with proteins. Also, the separation buffer can be adjusted by the derivatization solution to match the conditions of derivatization without sample loss. The effect of the separation buffer on the derivatization reaction was investigated and the results showed that even a strong acidic solution and multiple additives can be adopted in the separation buffer without destroying the post-column derivatization of proteins. Under the optimized conditions, the highly sensitive detection of BSA was achieved with a detection limit of 3.3 nmol L(-1) and a linear calibration range from 0.007 to 0.1 mg mL(-1). The proposed CE-LIF system with a post-column membrane reactor was also successfully applied to the separation and detection of proteins in rat liver and loach muscle. PMID:24015400

Liu, Fan; Zhang, Lingyi; Qian, Junhong; Ren, Jun; Gao, Fangyuan; Zhang, Weibing

2013-09-30

50

Diffusion and Sorption of Organic Liquids Through Polymer Membranes. VII. Elastomers Versus Acetic Acid and Dichloroacetic Acid  

Microsoft Academic Search

Diffusion coefficients of five elastomer membranes, viz., nitrile butadiene rubber, styrene–butadiene rubber, ethylene–propylene–diene terpolymer, neoprene, and natural rubber with acetic acid and dichloroacetic acids have been obtained from gravimetric sorption experiments. For acetic acid, the diffusion seems to follow the expected Fickian mechanism whereas for dichloroacetic acid, the diffusion appears to follow the non-Fickian mechanism for natural rubber and nitrile

T. M. Aminabhavi; R. S. Khinnavar; R. H. Balundgi

1994-01-01

51

Serum protein fractionation using supported molecular matrix electrophoresis.  

PubMed

Supported molecular matrix electrophoresis (SMME), in which a hydrophilic polymer such as PVA serves as a support within a porous PVDF membrane, was recently developed. This method is similar to cellulose acetate membrane electrophoresis but differs in the compatibility to glycan analysis of the separated bands. In this report, we describe the first instance of the application of SMME to human serum fractionation, and demonstrate the differences with serum fractionation by cellulose acetate membrane electrophoresis. The SMME membrane exhibited almost no EOF during electrophoresis, unlike the cellulose acetate membrane, but afforded comparative results for serum fractionation. The visualization of each fraction was achieved by conventional staining with dye such as Direct Blue-71, and objective quantification was obtained by densitometry after inducing membrane transparency with 1-nonene. Immunostaining was also achieved. Moreover, mass spectrometric analysis of both N-linked and O-linked glycans from the separated bands was demonstrated. Serum fractionation and glycan profiling of each fraction using SMME will enable novel insights into the relationships between various glycosylation profiles and disease states. PMID:23765906

Dong, Weijie; Matsuno, Yu-Ki; Kameyama, Akihiko

2013-07-26

52

Effect of electro-chemical properties of chloride salts on their diffusional parameters in symmetrical cellulose acetate membranes  

Microsoft Academic Search

A relation was obtained between electro-chemical properties of alkali, alkali-earth and aluminium-chlorides (LiCl, NaCl, KCl, RbCl, CsCl, MgCl2, CaCl2, AlCl3) and the distribution coefficient K and the overall diffusion coefficients D in symmetrical cellulose acetate membranes. Symmetrical cellulose acetate membranes was cast to have a wider range of water content, 15–30%. K and D were measured by the unsteady- and

Haruhiko Ohya; Svetlana I Semenova; Toshinori Fujimoto; Jun Ogihara; Shinichi Fukaya; Kousuke Mori; Masahiko Aihara; Youichi Negishi

2001-01-01

53

Investigation of the pore structure and morphology of cellulose acetate membranes using small-angle neutron scattering. 2: Ultrafiltration and reverse-osmosis membranes  

SciTech Connect

Pore structure in cellulose acetate ultrafiltration (UF) and reverse-osmosis (RO) membranes has been studied using small-angle neutron scattering. Scattering experiments were carried out on dry membranes as well as on membranes swollen with deuterated solvents (D[sub 2]O and CD[sub 3]OD). In addition, the RO membranes were studied both before and after annealing (a process of heating a membrane in a water bath at [approximately]75 C to improve its separation properties). The pore surface in UF membranes was found to be smooth and nonfractal, as evidenced by the fourth power law behavior at high Q. Values of average pore sizes obtained for dry and solvent swollen membranes agree well with pore sizes obtained by other methods. For cellulose acetate RO membranes in their dry state, the unannealed membrane appears to consist of two discrete pore size distributions in the intermediate and high Q region while the annealed membrane contains a much wider distribution of pore sizes. These results give a good account of the changes occurring in the structure of RO membranes as a result of annealing, and agree well with the prediction of other authors.

Kulkarni, S.; Krause, S. (Rensselaer Polytechnic Inst., Troy, NY (United States)); Wignall, G.D. (Oak Ridge National Lab., TN (United States). Solid State Div.)

1994-11-07

54

Analysis of steric partition behavior of molecules in membranes using statistical physics. Application to gel chromatography and electrophoresis.  

PubMed Central

The principles of statistical physics are used to formulate general expressions for the steric partition behavior of molecules in both random and ordered membrane structures that may be applied to any shape of the solute and/or the volume-excluding element of the membrane. These expressions fully define partitioning in terms of the volume excluded to point molecules and to finite-sized molecules. The mean effective exclusion volume for a molecule is calculated as a function of a global interaction energy, which varies with position, conformation, and orientation of the molecule. It allows consideration of electrostatic and other nonsteric factors. To test the model, specific partition functions are derived for several simple geometries describing the membrane and solute. Frequently, the derived expressions agree with past analyses; however, a new expression describing partitioning within an random network of fibers is derived. It agrees with past results only in the limit of low exclusion volumes. With greater volume exclusions, past results greatly overestimate the partition function. It is applied to gel electrophoresis and chromatography and survives testing with available experimental data. Unlike past analyses, it predicts nonlinear Ferguson plots for agarose gel electrophoresis. In addition, an analytical expression predicting the minimum radius of a sphere excluded from a random fiber matrix is derived, tested, and found to agree with experimental data.

Schnitzer, J E

1988-01-01

55

Optical, bactericidal and water repellent properties of electrospun nano-composite membranes of cellulose acetate and ZnO.  

PubMed

In this report, ZnO nanoparticles embedded cellulose acetate (CA) fibrous membrane with multifunctional properties have been prepared through electrospinning method. The morphology of the electrospun composite membrane was analyzed by scanning electron microscope (SEM). It was found that the polymer concentration in the solution has a significant effect on the morphology of the fibers. The optical property of the sample was tested using photo luminescence (PL) spectra. There is no significant change in the emission features of cellulose acetate with the addition of ZnO. The anti-bacterial property of the sample was studied using disk diffusion method. The wettability of the pure and composite fibrous membrane was also studied by measuring the contact angle of water on the membrane. It was observed that the embedded ZnO in the CA was responsible for the hydrophobic nature of the surface. PMID:24066357

Anitha, S; Brabu, B; John Thiruvadigal, D; Gopalakrishnan, C; Natarajan, T S

2013-07-01

56

Pervaporation separation of water-acetic acid mixtures through poly(vinyl alcohol) membranes crosslinked with glutaraldehyde  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA) membranes crosslinked with glutaraldehyde (GA) were prepared by a solution method for the pervaporation separation of acetic acid-water mixtures. In the solution method, dry PVA films were crosslinked by immersion for 2 days at 40°C in reaction solutions which contained different contents of GA, acetone and a catalyst, HCl. In order to fabricate the crosslinked PVA membranes

Choong-Kyun Yeom; Kew-Ho Lee

1996-01-01

57

Red blood cell storage in SAGM and AS3: a comparison through the membrane two-dimensional electrophoresis proteome  

PubMed Central

Background SAGM is currently the standard additive solution used in Europe, while AS-3 is the third additive solution that has been licensed in the USA, and is also the one used in part of Canada. Although AS-3 is based on a saline-adenine-glucose solution, it also contains citrate and phosphate. Storage of red blood cell concentrates in CPD-SAGM is known to lead to the accumulation of a wide series of storage lesions, including membrane protein fragmentation and vesiculation, as we could previously determine through 2-dimensional gel electrophoresis. Materials and methods. Through 2D-SDS-IEF-polyacrilamide gel electrophoresis we performed a time course analysis (day 0, 21 and 42 of storage) of red blood cell membranes from leukocyte-filtered concentrates either stored in CPD-SAGM or CP2D-AS-3. Results and discussion. From the present study it emerges that the membrane protein profile of red blood cells stored in presence of AS-3 appears to be slightly different from (better than) previous reports on SAGM-stored counterparts. However, the increase of total membrane spot number due to the presence of fragments at day 21 and the significant decrease at day 42 are suggestive of a universal phenomenon which is not efficiently tackled by either of the two additive solutions investigated in the present study. Conclusion To further delve into the storage lesion issue for RBCs stored in AS-3, it would be interesting in the future to assay metabolic changes over storage progression as well.

D'Amici, Gian Maria; Mirasole, Cristiana; D'Alessandro, Angelo; Yoshida, Tatsuro; Dumont, Larry J.; Zolla, Lello

2012-01-01

58

Kininogenase activity in plasma membranes and cell organelles from rabbit kidney cortex: Subcellular localization of renal kallikrein by free-flow electrophoresis and density-gradient fractionation  

Microsoft Academic Search

Kininogenase activity in plasma membranes and cell organelles from rabbit kidney cortex: Subcellular localization of renal kallikrein by free-flow electrophoresis and density-gradient fractionation. Subcellular fractions were prepared from a rabbit kidney cortex homogenate by density gradient and free-flow electrophoresis techniques. After enzymatic and morphologic characterization, we determined the kininogenase activity in the different fractions. This activity was present in those

Hans G Heidrich; Reinhard Geiger

1980-01-01

59

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

60

Water in polymer membranes. 4. Raman scattering from cellulose acetate films  

Microsoft Academic Search

Raman scattering was observed from thin film optical waveguides of cellulose acetate exposed to water vapor from 0% to 100% relative humidity (RH), and from dilute solutions of water in methyl acetate. Spectra of cellulose acetate (CA398, 39.8% acetyl) at low RH and cellulose triacetate (CTA) at low and high RH are consistent with the presence of water monomers that

J. R. Scherer; G. F. Bailey; S. Kint; R. Young; D. P. Malladi; B. Bolton

1985-01-01

61

Fouling propensity and separation efficiency of epoxidated polyethersulfone incorporated cellulose acetate ultrafiltration membrane in the retention of proteins  

NASA Astrophysics Data System (ADS)

Epoxidated polyethersulfone (EPES) incorporated cellulose acetate (CA) ultrafiltration membranes were prepared by diffusion induced precipitation technique in the absence and presence of pore former polyethyleneglycol-600. Effect of blend ratio on the compatibility, thermal stability, mechanical strength, hydrophilicity, morphology, pure water flux, protein adsorption resistance, protein separation efficiency and fouling propensity of the CA/EPES blend membranes was evaluated. Addition of EPES results in the formation of thin separating layer and spongy sub layer in CA/EPES blend membranes. The efficiency of these membranes in the separation of commercially important proteins such as bovine serum albumin, egg albumin, pepsin and trypsin was studied and found to be enhanced as compared to CA membranes. The fouling-resistant capability of the membranes was studied by bovine serum albumin as the model foulant and flux recovery ratio of the membranes were calculated. Attempts have been made to correlate the changes in membrane morphology with pure water flux, hydraulic resistance, thermal and mechanical stability, separation efficiency and antifouling property of the CA/EPES membranes. The optimal combination of CA and EPES, thus allows the preparation of high performance UF membranes which are sufficiently dense to retain proteins and at the same time give economically viable fluxes.

Jayalakshmi, A.; Rajesh, S.; Mohan, D.

2012-10-01

62

Identification of Campylobacter jejuni and C. coli by gel electrophoresis of the outer membrane proteins.  

PubMed Central

Analysis of the electrophoretic profiles of the outer membrane proteins could be used to differentiate Campylobacter jejuni (16 strains) from Campylobacter coli (10 strains). This observation was confirmed by the study of DNA homology obtained by a quantitative filter hybridization method. The hippurate hydrolysis test gave a poor correlation with the results of differentiation obtained by DNA homology studies and outer membrane protein profile. Images

Derclaye, I; Delor, I; Van Bouchaute, M; Moureau, P; Wauters, G; Cornelis, G R

1989-01-01

63

Facile fouling resistant surface modification of microfiltration cellulose acetate membranes by using amino acid L-DOPA.  

PubMed

A major obstacle in the widespread application of microfiltration membranes in the wet separation processes such as wastewater treatment is the decline of permeates flux as a result of fouling. This study reports on the surface modification of cellulose acetate (CA) microfiltration membrane with amino acid L-3,4-dihydroxy-phenylalanine (L-DOPA) to improve fouling resistance of the membrane. The membrane surface was characterised using Fourier transform infrared spectroscopy (FTIR), water contact angle and zeta potential measurement. Porosity measurement showed a slight decrease in membrane porosity due to coating. Static adsorption experiments revealed an improved resistance of the modified membranes towards the adhesion of bovine serum albumin (BSA) as the model foulant. Dead end membrane filtration tests exhibited that the fouling resistance of the modified membranes was improved. However, the effect of the modification depended on the foulant solution concentration. It is concluded that L-DOPA modification is a convenient and non-destructive approach to enable low-BSA adhesion surface modification of CA microfiltration membranes. Nevertheless, the extent of fouling resistance improvement depends on the foulant concentration. PMID:23985522

Azari, Sara; Zou, Linda; Cornelissen, Emile; Mukai, Yasushito

2013-01-01

64

Selective oxidation of ethanol to acetic acid in highly efficient polymer electrolyte membrane-direct ethanol fuel cells  

Microsoft Academic Search

The selective conversion of ethanol into potassium acetate with concomitant production of electrical energy has been achieved in both passive and active direct fuel cells containing platinum-free electrodes and an anion-exchange polymer membrane. The power densities supplied by the passive systems at r.t. can be as high as 55mWcm?2, while the active systems can deliver up to 170mWcm?2 at 80°C.

Claudio Bianchini; Valentina Bambagioni; Jonathan Filippi; Andrea Marchionni; Francesco Vizza; Paolo Bert; Alessandro Tampucci

2009-01-01

65

Melittin-induced changes in thylakoid membranes: particle electrophoresis and light scattering study.  

PubMed

Thylakoids were used as a model system to evaluate the effect of bee venom peptide melittin (Mt) on membrane surface charge. At neutral pH, thylakoid membrane surfaces carry excess negative electrical charge. Mt strongly altered the electrophoretic mobility (EPM) of 'low-salt' thylakoids and did not significantly change the EPM of 'high-salt' thylakoids. Mt increased the primary ionic-exchange processes across the 'low-salt' thylakoid membranes, while it did not affect those of 'high-salt' thylakoids. Mt decreased the proton gradient generation on the membranes at both ionic strengths, but it affected more strongly the 'high-salt' than that of 'low-salt' thylakoids. The primary photochemical activity of photosystem II, estimated by the ratio Fv/Fm, was not influenced by the low Mt concentrations. It decreased only when chloroplasts had been incubated with higher Mt concentrations and this effect was better expressed in 'low-salt' than in 'high-salt' thylakoid membranes. PMID:15110936

Doltchinkova, Virjinia; Georgieva, Katya; Traytcheva, Nelly; Slavov, Chavdar; Mishev, Kiril

2004-06-01

66

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

67

Electrophoresis of cellular membrane components creates the directional cue guiding keratocyte galvanotaxis  

PubMed Central

Summary Background Motile cells exposed to an external direct current electric field will reorient and migrate along the direction of the electric potential in a process known as galvanotaxis. The underlying physical mechanism that allows a cell to sense an electric field is unknown, although several plausible hypotheses have been proposed. In this work we evaluate the validity of each of these mechanisms. Results We find that the directional motile response of fish epidermal cells to the cathode in an electric field does not require extracellular sodium or potassium, is insensitive to membrane potential, and also insensitive to perturbation of calcium, sodium, hydrogen, or chloride ion transport across the plasma membrane. Cells migrate in the direction of applied forces from laminar fluid flow, but reversal of electroosmotic flow did not affect the galvanotactic response. Galvanotaxis fails when extracellular pH is below 6, which suggests that the effective charge of membrane components may be a crucial factor. Slowing the migration of membrane components with an increase in aqueous viscosity slows the kinetics of the galvanotactic response. In addition inhibition of PI3K reverses the cell’s response to the anode, suggesting the existence of multiple signaling pathways downstream of the galvanotactic signal. Conclusions Our results are most consistent with the hypothesis that electrophoretic redistribution of membrane components of the motile cell is the primary physical mechanism for motile cells to sense an electric field. This chemical polarization of the cellular membrane is then transduced by intracellular signaling pathways canonical to chemotaxis to dictate the cell’s direction of travel.

Allen, Greg M.; Mogilner, Alex; Theriot, Julie A.

2013-01-01

68

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

NASA Astrophysics Data System (ADS)

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 intact carbonic anhydrase and hemoglobin were obtained from 14 and 20 pmol loadings. This methodology is also compatible with blotting high molecular weight proteins, as seen for 6 pmol of the 150 kDa monoclonal antibody anti-[beta]-galactosidase transferred to Goretex. Polypropylene, Teflon, Nafion and polyvinylidene difluoride (PVDF) also produced good spectra following diffusive transfer. Only analysis from PVDF required that the membrane be kept wet prior to application of matrix. Considerations in mass accuracy for analysis from large-area membranes with continuous extraction and delayed extraction were explored, as were remedies for surface charging. Vapor phase CNBr cleavage was applied to membrane-bound samples for peptide mapping.

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

1997-12-01

69

Gluten-sensitive enteropathy in Irish setter dogs: characterisation of jejunal microvillar membrane proteins by two-dimensional electrophoresis.  

PubMed

This study investigated whether gluten-sensitive enteropathy (GSE) in Irish setter dogs was associated with underlying structural abnormalities of microvillar membrane proteins. Jejunal biopsies taken from eight-month-old GSE-affected dogs reared on a normal, gluten-containing diet exhibited partial villous atrophy and contained more intra-epithelial lymphocytes than controls. The morphological abnormalities were reversed by feeding a gluten-free diet for five months and the changes were accompanied by an increase in the mucosal activity of the microvillar hydrolases, particularly aminopeptidase N and dipeptidyl aminopeptidase IV, which reverted to pre-treatment levels after a gluten challenge. Two-dimensional electrophoresis of microvillar membrane proteins isolated from GSE-affected dogs revealed an essentially normal protein map that was comparable to controls. The exception was an intense 85 kDa protein spot that diminished when the affected dogs were fed a gluten-free diet and re-intensified after a gluten challenge. PMID:9243723

Pemberton, P W; Lobley, R W; Holmes, R; Sørensen, S H; Batt, R M

70

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

71

Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) membranes for ethyl acetate removal from water.  

PubMed

In this study, poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) with low crystallinity was applied as the membrane material for pervaporative separating ethyl acetate (EtAc) from its aqueous solutions. The drying conditions during membrane fabrication by means of casting the PVDF-HFP solution dominated the obtained membrane morphologies when the polar solvents such as dimethylacetamide (DMAc) and acetone were used. It was demonstrated that both the DMAc-cast and acetone-cast PVDF-HFP membranes vacuum-dried at 60 degrees C were dense but had different crystalline structures. Predominantly alpha and gamma crystalline phases were found in the acetone-cast and DMAc-cast PVDF-HFP membranes, respectively. And the different pervaporative separating performances of the two solvent-cast PVDF-HFP membranes were well explained in terms of different solution-diffusion properties which were induced from the permeants/polymer interactions on the base of the polarity differences between permeants and the two solvent-cast PVDF-HFP membranes. PMID:17884287

Tian, Xiuzhi; Jiang, Xue

2007-08-17

72

Dynamic supported liquid membrane tip extraction of glyphosate and aminomethylphosphonic acid followed by capillary electrophoresis with contactless conductivity detection.  

PubMed

A dynamic supported liquid membrane tip extraction (SLMTE) procedure for the effective extraction and preconcentration of glyphosate (GLYP) and its metabolite aminomethylphosphonic acid (AMPA) in water has been investigated. The SLMTE procedure was performed in a semi-automated dynamic mode and demonstrated a greater performance against a static extraction. Several important extraction parameters such as donor phase pH, cationic carrier concentration, type of membrane solvent, type of acceptor stripping phase, agitation and extraction time were comprehensively optimized. A solution of Aliquat-336, a cationic carrier, in dihexyl ether was selected as the supported liquid incorporated into the membrane phase. Quantification of GLYP and AMPA was carried out using capillary electrophoresis with contactless conductivity detection. An electrolyte solution consisting of 12 mM histidine (His), 8 mM 2-(N-morpholino)ethanesulfonic acid (MES), 75 microM cetyltrimethylammonium bromide (CTAB), 3% methanol, pH 6.3, was used as running buffer. Under the optimum extraction conditions, the method showed good linearity in the range of 0.01-200 microg/L (GLYP) and 0.1-400 microg/L (AMPA), acceptable reproducibility (RSD 5-7%, n=5), low limits of detection of 0.005 microg/L for GLYP and 0.06 microg/L for AMPA, and satisfactory relative recoveries (90-94%). Due to the low cost, the SLMTE device was disposed after each run which additionally eliminated the possibility of carry-over between runs. The validated method was tested for the analysis of both analytes in spiked tap water and river water with good success. PMID:20696433

See, Hong Heng; Hauser, Peter C; Sanagi, M Marsin; Ibrahim, Wan Aini Wan

2010-07-23

73

Preparation of isoproturon and 2,4-dichlorophenoxy acetic acid imprinted membranes: Ion transport study  

Microsoft Academic Search

Molecular imprinting technique is used for preparing molecularly imprinted polymer (MIP) membranes of desired recognition site, selectivity and porosity. The novelty of present work is to use a new approach for preparing imprinted monolith membrane, to study the effect of membrane porosity generated due to molecular imprinting on irreversible thermodynamical characteristics like membrane potential, ion transport, fixed charge density and

K. P. Singh; R. Dobhal; R. K. Prajapati; Satish Kumar; Sanjesh; M. A. Ansari

2010-01-01

74

Analysis of nephritogenic antigens in human glomerular basement membrane by two-dimensional gel electrophoresis.  

PubMed

Collagenase digests of GBM were partially purified by column chromatography and analyzed by 2-D gel electrophoresis. Silver staining of 2-D gels showed charge- and size-related heterogeneity of proteins in the 45 to 50 kDa and 25 to 27 kDa regions. These components were transferred to nitrocellulose sheets and reacted with 10 human anti-GBM autoantibodies. Detection of bound anti-GBM autoantibodies to blotted proteins was carried out with peroxidase-labeled goat anti-human IgG and revealed binding predominantly to the cationic (pI 8 to 9.0) 45 to 50 kDa and 25 to 27 kDa components. Positive-staining patterns of blotted proteins were similar with all anti-GBM autoantibodies except that three sera additionally identified neutral (pI 5.5 to 6.5) protein components. One anti-GBM autoantibody, which developed following renal transplantation, lacked reactivity with the most cationic components in the 25 to 27 kDa region. These findings suggest heterogeneity of nephritogenic GBM antigens. The cationic 45 to 50 kDa components were sensitive to reduction, while one neutral 45 to 50 kDa component was resistant; a complex array of 25 to 30 kDa proteins (pI 5.5 to 7.5) were observed by silver staining postreduction. None of the reduced protein components reacted with anti-GBM antibodies, suggesting that epitopes on nephritogenic GBM antigens may be related to disulfide-bonded regions. Although there is variable immunohistochemical reactivity of anti-GBM autoantibodies with the GBM of infant kidneys, 2-D gels of collagenase-digested human infant GBM blotted and reacted with anti-GBM autoantibodies and showed staining patterns similar to that of adult GBM. These studies demonstrate the presence of nephritogenic antigens in the GBM of immature human kidney which are not detectable by immunohistochemical analysis. PMID:2985699

Yoshioka, K; Kleppel, M; Fish, A J

1985-06-01

75

A novel precursor composed of polycarbosilane and palladium(II) acetate for a SiC-based gas separation membrane  

NASA Astrophysics Data System (ADS)

Organic-inorganic conversion process of a novel precursor composed of polycarbosilane and palladium(II) acetate was investigated in order to develop a SiC-based gas separation membrane. It was found that the precursor was converted to inorganic material forming Si-C-Si, Si-O-Si and Si-O-C network and evolving hydrogen, methane, ethane, carbon monoxide and carbon dioxide gases in a temperature range of 350-1000K. Furthermore, it was found that the volume shrinkage of precursor during pyrolysis process was 50%, which is 14% lower than that of PCS, because of efficient crosslinking of PCS and network formation.

Idesaki, Akira; Sugimoto, Masaki; Yoshikawa, Masahito

2011-04-01

76

Water in polymer membranes. 4. Raman scattering from cellulose acetate films  

SciTech Connect

Raman scattering was observed from thin film optical waveguides of cellulose acetate exposed to water vapor from 0% to 100% relative humidity (RH), and from dilute solutions of water in methyl acetate. Spectra of cellulose acetate (CA398, 39.8% acetyl) at low RH and cellulose triacetate (CTA) at low and high RH are consistent with the presence of water monomers that are weakly hydrogen bonded to acetyl C=O groups. Differences between the spectra of water in CA398 and CTA at low RH are attributed to sequential hydrogen bonding involving OH groups in CA398. At high RH, CA398 and CTA (to a lesser extent) show bands attributed to water/water interactions that are similar to those found in sequentially hydrogen-bonded hydrates. CA398 films that are annealed at high temperatures exhibit decreased water/water interactions at high RH. Exposure of CA398 films to D/sub 2/O converts > 90% of all polymer OH groups to OD groups. This indicates that water is accessible to nearly all regions of the polymer containing OH groups. Annealing does not alter this accessibility but does reduce the total water content by roughly half, at 100% RH. Hydrogen-bonded C=O groups are associated with a band centered at 1731 cm/sup -1/ which increases in intensity with increasing water content in the film but does not shift in frequency. 38 references, 16 figures, 1 table.

Scherer, J.R.; Bailey, G.F.; Kint, S.; Young, R.; Malladi, D.P.; Bolton, B.

1985-01-17

77

ADSORPTION AND MEMBRANE SEPARATION MEASUREMENTS WITH MIXTURES OF ETHANOL, ACETIC ACID, AND WATER  

EPA Science Inventory

Biomass fermentation produces ethanol and other renewable biofuels. Pervaporation using hydrophobic membranes is potentially a cost-effective means of removing biofuels from fermentation broths for small- to medium-scale applications. Silicalite-filled polydimethylsiloxane (PDMS)...

78

Permeation and Separation Characteristics of Acetic Acid?Water Mixtures Through Poly(Vinyl Alcohol)\\/Malic Acid Membranes by Evapomeation and Temperature Difference Controlled Evapomeation  

Microsoft Academic Search

The characteristics of permeation and separation of acetic acid?water mixtures through 85\\/15 (v\\/v) poly(vinyl alcohol)\\/malic acid (PVA\\/MA) membranes were investigated by evapomeation (EV) and temperature difference controlled evapomeation (TDEV) methods. The effects of permeation temperature, membrane surrounding temperature, and feed composition on the permeation rate and the separation factor were studied. The permeation rates increased but separation factors decreased with

Nuran I??klan; Oya ?anl?

2005-01-01

79

Pervaporation of water and ethanol using a cellulose acetate butyrate membrane  

Microsoft Academic Search

Okada and Matsuura's transport equations for pervaporation give rise to three fundamental parameters, namely, interfacial saturation vapor pressure P*, liquid transport parameter A\\/[delta], and vapor transport parameter B\\/[delta]. The effects of the chemical nature of the membrane material and the upstream operating pressures of 101.3 and 303.9 kPa on the above parameters were investigated from the pervaporation data at laboratory

W. S. Wu; W. W. Y. Lau; G. P. Rangaiah; S. Sourirajan

1993-01-01

80

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

81

Cationic electrophoresis.  

PubMed

Denaturing, discontinuous electrophoresis in the presence of SDS has become a standard method for the protein scientist. However, there are situations where this method produces suboptimal results. In these cases, electrophoresis in the presence of positively charged detergents such as cetyltrimethylammonium bromide (CTAB) may work considerably better. Methods for electrophoresis and staining of such gels are presented. PMID:22585477

Buxbaum, Engelbert

2012-01-01

82

On-line combination of capillary isoelectric focusing and capillary non-gel sieving electrophoresis using a hollow-fiber membrane interface: a novel two-dimensional separation system for proteins  

Microsoft Academic Search

A novel two-dimensional (2D) separation system for proteins was reported. In the system, a piece of dialysis hollow-fiber membrane was employed as the interface for on-line combination of capillary isoelectric focusing (CIEF) and capillary non-gel sieving electrophoresis (CNGSE). The system is similar equivalent to two-dimensional polyacrylamide gel electrophoresis (2D PAGE), by transferring the principal of 2D PAGE separation to the

Hechun Liu; Chun Yang; Qing Yang; Weibing Zhang; Yukui Zhang

2005-01-01

83

Effects of oxidoreduction potential combined with acetic acid, NaCl and temperature on the growth, acidification, and membrane properties of Lactobacillus plantarum  

Microsoft Academic Search

The effects of oxidoreduction potential (Eh) combined with acetic acid, NaCl and temperature on the growth, acidification, and membrane properties of Lactobacillus plantarum were studied. The culture medium was set at pH 5, and two different Eh values were adjusted using nitrogen (Eh=+350 mV) or hydrogen (Eh=?300 mV) gas. In reducing condition, the growth was slowed and the acidification delayed

Ariane Ouvry; Yves Waché; Raphaëlle Tourdot-Maréchal; Charles Diviès; Rémy Cachon

2002-01-01

84

DESORPTION OF ETHYL ACETATE-WATER MIXTURE BY USING CROSS-LINKED POLY(VINYLALCOHOL) MEMBRANE AND COMPARISON OF RESULTS WITH PERVAPORATION  

Microsoft Academic Search

In this study using poly(vinylalcohol) (PVOH) membranes cross-linked with tartaric acid (Tac) desorption experiments were performed for selected concentrations of binary ethyl acetate (EtAc)-water mixture at temperatures of 30°, 40°, and 50°C to determine sorption of components. Sorption values measured were compared with those estimated by the Flory-Huggins approach. Additionally, desorption results were compared with pervaporation results of another study

Sevinc Korkmaz; Yavuz Salt; Ayca Hasanoglu; Semra Ozkan; Salih Dincer

2008-01-01

85

Effect of electro-chemical properties of sodium salts of various anions on their diffusional parameters in symmetrical cellulose acetate membranes  

Microsoft Academic Search

A relation was obtained between electro-chemical properties of sodium salts (NaCl, NaBr, and Na2SO4), and the thermodynamic property of permeability in symmetrical cellulose acetate membranes, the distribution coefficient K and the kinetic property, the overall diffusion coefficients D.K and D were obtained by the method we proposed using measured unsteady- and steady-state dialysis data. The K values increase with the

Haruhiko Ohya; Svetlana I Semenova; Aya Sawada; Shinichi Fukaya; Yohei Suzuki; Masahako Aihara; Youichi Negishi

2001-01-01

86

Preparative isoelectric focusing and preparative electrophoresis of hydrophobic Candida albicans cell wall proteins with in-line transfer to polyvinylidene difluoride membranes for sequencing.  

PubMed

Hydrophobic proteins in the cell wall of the opportunistic fungal pathogen Candida albicans are involved in adhesion of this organism to host tissue and thus play a role in its pathogenicity. The hydrophobic nature of these proteins results in their loss during purification due to adsorption to apparatus surfaces. This problem, combined with their low abundance, has made it problematic to purify the hydrophobic proteins in sufficient quantity for sequencing or biochemical analysis. We describe a system that combines preparative isoelectric focusing with continuous elution preparative electrophoresis. The system provides a two-dimensional protein separation while maintaining protein solubility and minimizing protein loss due to adsorption. In addition, we have added an in-line transfer of electrophoretic fractions directly to polyvinylidene difluoride (PVDF) membranes, which further reduces both exposure to apparatus surfaces and purification time. PMID:9629897

Masuoka, J; Glee, P M; Hazen, K C

1998-05-01

87

Enzyme electrophoresis, sero- and subtyping, and outer membrane protein characterization of two Neisseria meningitidis strains involved in laboratory-acquired infections.  

PubMed Central

Two cases of laboratory-acquired infections due to Neisseria meningitidis were suspected to have occurred in two French hospitals. The first case occurred shortly, i.e., 3 days, after one strain had been handled by a laboratory technician, and the link between this strain and the strain causing meningitis was easily established. In the second case, infection occurred 3 weeks after 10 strains had been handled by a technician. In this case, it was necessary to use high-resolution markers in order to establish the link between the infecting strain and 1 of the 10 strains handled. The antigenic formulae of the two infecting strains (serogroup:serotype:subtype) were, respectively, C:NT:P1.12 and B:2a:P1.2. Outer membrane protein profile analysis and multilocus enzyme electrophoresis unequivocally confirmed the identity of the respective strains. Images

Guibourdenche, M; Darchis, J P; Boisivon, A; Collatz, E; Riou, J Y

1994-01-01

88

Plasticizer effect and comparative evaluation of cellulose acetate and ethylcellulose-HPMC combination coatings as semipermeable membranes for oral osmotic pumps of naproxen sodium.  

PubMed

The objective of this study was to compare the performance of cellulose acetate (CA) and ethylcellulose (EC)-HPMC combination coatings as semipermeable membranes (SPMs) for osmotic pump tablets (OPTs) of naproxen sodium (NPS) so as to deliver a constant, predetermined amount of drug in solution form over a fixed span of time, independent of external environmental conditions. Osmotic pump tablets were designed with different coating variables and optimized in terms of nature of plasticizer, membrane thickness, and orifice diameter. The effect of insertion of an inner microporous film around the NPS core to minimize deformation of the SPM due to peristaltic movement of the gut was also studied. Osmotic pump tablets composed of membranes with water-soluble plasticizer, propyleneglycol (PG), released drug mainly through diffusion, whereas those designed with CA and EC-HPMC (4:1) coats containing water-insoluble plasticizer, castor oil, released their contents by perfect zero-order kinetics over a prolonged period of time, though the average release rate that could be achieved with the EC-HPMC (4:1) membrane was only about half the rate achieved with the CA membrane for the same membrane thickness. Release rates for both the membranes decreased with increasing membrane thickness and were found to be independent of orifice diameter, agitation intensity, and pH of the dissolution medium. PMID:12056533

Ramakrishna, N; Mishra, B

2002-04-01

89

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

90

Preparation and application of functionalized cellulose acetate/silica composite nanofibrous membrane via electrospinning for Cr(VI) ion removal from aqueous solution.  

PubMed

Novel NH(2)-functionalized cellulose acetate (CA)/silica composite nanofibrous membranes were successfully prepared by sol-gel combined with electrospinning technology. Tetraethoxysilane (TEOS) as a silica source, CA as precursor and 3-ureidopropyltriethoxysilane as a coupling agent were used in membrane preparation. The membrane's chemical and morphological structures were investigated by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), element analyzer, Fourier-transform infrared spectroscopy (FTIR) and N(2) adsorption-desorption isotherms. The composite nanofibrous membranes exhibited high surface area and porosity. The membranes were used for Cr(VI) ion removal from aqueous solution through static and dynamic experiments. The adsorption behavior of Cr(VI) can be well described by the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) is estimated to be 19.46 mg/g. The membrane can be conveniently regenerated by alkalization. Thus the composite membrane prepared from biodegradable raw material has potential applications in the field of water treatment. PMID:22858801

Taha, Ahmed A; Wu, Yi-na; Wang, Hongtao; Li, Fengting

2012-08-02

91

Removal of pesticides and other micropollutants with cellulose-acetate, polyamide and ultra-low pressure reverse osmosis membranes  

Microsoft Academic Search

In 1995 several membrane manufacturers started to sell ultra low-pressure reverse osmosis membranes. The specifications of these membranes indicated that they have rejections for dissolved salts comparable to “conventional” composite (polyamide) membranes, while the required feed pressure to realize a specific production capacity is 30–40% less. This article describes the results of a preliminary study on the performance of these

J. A. M. H. Hofman; E. F. Beerendonk; H. C. Folmer; J. C. Kruithof

1997-01-01

92

Simulating Electrophoresis.  

ERIC Educational Resources Information Center

|Describes a DNA fingerprinting simulation that uses vegetable food coloring and plastic food containers instead of DNA and expensive gel electrophoresis chambers. Allows students to decipher unknown combinations of dyes in a method similar to that used to decipher samples of DNA in DNA fingerprint techniques. (JRH)|

Moertel, Cheryl; Frutiger, Bruce

1996-01-01

93

A difference gel electrophoresis study on thylakoids isolated from poplar leaves reveals a negative impact of ozone exposure on membrane proteins.  

PubMed

Populus tremula L. x P. alba L. (Populus x canescens (Aiton) Smith), clone INRA 717-1-B4, saplings were subjected to 120 ppb ozone exposure for 28 days. Chloroplasts were isolated, and the membrane proteins, solubilized using the detergent 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC), were analyzed in a difference gel electrophoresis (DiGE) experiment comparing control versus ozone-exposed plants. Extrinsic photosystem (PS) proteins and adenosine triphosphatase (ATPase) subunits were detected to vary in abundance. The general trend was a decrease in abundance, except for ferredoxin-NADP(+) oxidoreductase (FNR), which increased after the first 7 days of exposure. The up-regulation of FNR would increase NAPDH production for reducing power and detoxification inside and outside of the chloroplast. Later on, FNR and a number of PS and ATPase subunits decrease in abundance. This could be the result of oxidative processes on chloroplast proteins but could also be a way to down-regulate photochemical reactions in response to an inhibition in Calvin cycle activity. PMID:21520910

Bohler, Sacha; Sergeant, Kjell; Hoffmann, Lucien; Dizengremel, Pierre; Hausman, Jean-Francois; Renaut, Jenny; Jolivet, Yves

2011-05-19

94

Parallel Characterization of Anaerobic Toluene- and Ethylbenzene-Degrading Microbial Consortia by PCR-Denaturing Gradient Gel Electrophoresis, RNA-DNA Membrane Hybridization, and DNA Microarray Technology  

PubMed Central

A mesophilic toluene-degrading consortium (TDC) and an ethylbenzene-degrading consortium (EDC) were established under sulfate-reducing conditions. These consortia were first characterized by denaturing gradient gel electrophoresis (DGGE) fingerprinting of PCR-amplified 16S rRNA gene fragments, followed by sequencing. The sequences of the major bands (T-1 and E-2) belonging to TDC and EDC, respectively, were affiliated with the family Desulfobacteriaceae. Another major band from EDC (E-1) was related to an uncultured non-sulfate-reducing soil bacterium. Oligonucleotide probes specific for the 16S rRNAs of target organisms corresponding to T-1, E-1, and E-2 were designed, and hybridization conditions were optimized for two analytical formats, membrane and DNA microarray hybridization. Both formats were used to characterize the TDC and EDC, and the results of both were consistent with DGGE analysis. In order to assess the utility of the microarray format for analysis of environmental samples, oil-contaminated sediments from the coast of Kuwait were analyzed. The DNA microarray successfully detected bacterial nucleic acids from these samples, but probes targeting specific groups of sulfate-reducing bacteria did not give positive signals. The results of this study demonstrate the limitations and the potential utility of DNA microarrays for microbial community analysis.

Koizumi, Yoshikazu; Kelly, John J.; Nakagawa, Tatsunori; Urakawa, Hidetoshi; El-Fantroussi, Said; Al-Muzaini, Saleh; Fukui, Manabu; Urushigawa, Yoshikuni; Stahl, David A.

2002-01-01

95

Role of bis(monoacylglycero)phosphate in propranolol binding to phospholipid membranes under acidic conditions as measured by high-performance frontal analysis/capillary electrophoresis.  

PubMed

Bis(monoacylglycero)phosphate (BMP) is localized in acidic organelles such as late endosomes or lysosomes. It has been reported that BMP levels increase under phospholipidosis induced by cationic amphiphilic drugs. In the present study, the effect of BMP on the binding of propranolol (PRO) to phospholipid liposomes under acidic conditions was investigated. Binding experiments were conducted by high-performance frontal analysis/capillary electrophoresis. PRO showed nonspecific binding to BMP-containing liposomes (BMP:phosphatidylcholine = 1:4), when numbers of bound drug molecules per lipid molecule (r) ranged 0.01-0.06. Total binding affinity increased depending on the BMP content. Binding affinity was decreased by low ionic strength, or by substitution of BMP with diacylglycerol, suggesting that electrostatic interactions were involved. The binding-enhancement effect of BMP was almost equivalent to that of phosphatidylglycerol, and slightly larger than that of phosphatidylserine. An acidic environment (pH 5.0) decreased total binding affinity to BMP-containing liposomes. This could be explained by the pH-partition theory (i.e., the loss in affinity was caused by a decrease in the neutral form of the drug accessible to the membrane core). These results suggest that PRO binding is enhanced by BMP in late endosomes or lysosomes, whereas an acidic environment weakens such binding. PMID:22996699

Hamaguchi, Ryohei; Kuroda, Yukihiro; Tanimoto, Toshiko; Haginaka, Jun

2012-09-20

96

Cellulose Acetate Reverse Osmosis Membranes Made by Phase Inversion Method: Effects of a Shear Treatment Applied to the Casting Solution on the Membrane Structure and Performance  

Microsoft Academic Search

A mixture of equal parts of cellulose diacetate and cellulose triacetate was dissolved in dipropylene glycol and exposed to shear stresses of varying intensity on a three-roll calander. Asymmetric reverse osmosis membranes were prepared from these materials by the phase-inversion method. Reverse osmosis tests in a dead-end module provided membrane performance data. A structure analysis was performed by scanning electron

Mathias C. M. Nolte; Peter F. W. Simon; Myrna Aguiar del Toro; Karen Gerstandt; Wolfgang Calmano

2011-01-01

97

Assessing accumulation and biological effect of hydrophobic organic contaminants in water using caged Japanese medaka and deployed triolein-embedded cellulose acetate membranes.  

PubMed

Applicability of triolein-embedded cellulose acetate membrane (TECAM) to accumulation and potential biological effect assessment for hydrophobic organic contaminants (HOCs) was investigated compared with Japanese medaka. The results of field exposure showed that medaka and TECAMs accumulated contaminants in a similar pattern with good correlations between concentrations in medaka and TECAMs based on lipid weight for OCPs (r=0.96, p=0.01, n=9) and PAHs (r=0.73, p=0.01, n=13). Meanwhile, 2,3,7,8-TCDD equivalents (TEQs) of TECAM extracts detected by in vitro H4IIE cell bioassay corresponded well to hepatic EROD activities of exposed fish and TEQs of water samples. We concluded that TECAM could be utilized as a surrogate for biomonitoring organisms to assess the bioaccumulation of HOCs and potential biological effect. PMID:18958381

Luo, Jianping; Ma, Mei; Zha, Jinmiao; Wang, Zijian

2008-10-29

98

On-line combination of capillary isoelectric focusing and capillary non-gel sieving electrophoresis using a hollow-fiber membrane interface: a novel two-dimensional separation system for proteins.  

PubMed

A novel two-dimensional (2D) separation system for proteins was reported. In the system, a piece of dialysis hollow-fiber membrane was employed as the interface for on-line combination of capillary isoelectric focusing (CIEF) and capillary non-gel sieving electrophoresis (CNGSE). The system is similar equivalent to two-dimensional polyacrylamide gel electrophoresis (2D PAGE), by transferring the principal of 2D PAGE separation to the capillary format. Proteins were focused and separated in first dimension CIEF based on their differences in isoelectric points (pIs). Focused protein zones was transferred to the dialysis hollow-fiber interface, where proteins hydrophobically complexed with sodium dodecyl sulfate (SDS). The negatively charged proteins were electromigrated and further resolved by their differences in size in the second dimension CNGSE, in which dextran solution, a replaceable sieving matrix instead of cross-linked polyacrylamide gel was employed for size-dependent separation of proteins. The combination of the two techniques was attributed to high efficiency of the dialysis membrane interface. The feasibility and the orthogonality of the combined CIEF-CNGSE separation technique, an important factor for maximizing peak capacity or resolution elements, were demonstrated by examining each technique independently for the separation of hemoglobin and protein mixtures excreting from lung cancer cells of rat. The 2D separation strategy was found to greatly increase the resolving power and overall peak capacity over those obtained for either dimension alone. PMID:15680795

Liu, Hechun; Yang, Chun; Yang, Qing; Zhang, Weibing; Zhang, Yukui

2005-03-01

99

Triolein embedded cellulose acetate membrane as a tool to evaluate sequestration of PAHs in lake sediment core at large temporal scale.  

PubMed

Although numerous studies have addressed sequestration of hydrophobic organic compounds (HOCs) in laboratory, little attention has been paid to its evaluation method in field at large temporal scale. A biomimetic tool, triolein embedded cellulose acetate membrane (TECAM), was therefore tested to evaluate sequestration of six PAHs with various hydrophobicity in a well-dated sediment core sampled from Nanyi Lake, China. Properties of sediment organic matter (OM) varying with aging time dominated the sequestration of PAHs in the sediment core. TECAM-sediment accumulation factors (MSAFs) of the PAHs declined with aging time, and significantly correlated with the corresponding biota-sediment accumulation factors (BSAFs) for gastropod (Bellamya aeruginosa) simultaneously incubated in the same sediment slices. Sequestration rates of the PAHs in the sediment core evaluated by TECAM were much lower than those obtained from laboratory study. The relationship between relative availability for TECAM (MSAF(t)/MSAF(0)) and aging time followed the first order exponential decay model. MSAF(t)/MSAF(0) was well-related to the minor changes of the properties of OM varying with aging time. Compared with chemical extraction, sequestration reflected by TECAM was much closer to that by B. aeruginosa. In contrast to B. aeruginosa, TECAM could avoid metabolism and the influences from feeding and other behaviors of organisms, and it is much easier to deploy and ready in laboratory. Hence TECAM provides an effective and convenient way to study sequestration of PAHs and probably other HOCs in field at large temporal scale. PMID:22372719

Tao, Yuqiang; Xue, Bin; Yao, Shuchun; Deng, Jiancai; Gui, Zhifan

2012-03-14

100

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

101

Western Blotting using Capillary Electrophoresis  

PubMed Central

A microscale Western blotting system based on separating sodium-dodecyl sulfate protein complexes by capillary gel electrophoresis followed by deposition onto a blotting membrane for immunoassay is described. In the system, the separation capillary is grounded through a sheath capillary to a mobile X-Y translation stage which moves a blotting membrane past the capillary outlet for protein deposition. The blotting membrane is moistened with a methanol and buffer mixture to facilitate protein adsorption. Although discrete protein zones could be detected, bands were broadened by ~1.7-fold by transfer to membrane. A complete Western blot for lysozyme was completed in about one hour with 50 pg mass detection limit from low microgram per milliliter samples. These results demonstrate substantial reduction in time requirements and improvement in mass sensitivity compared to conventional Western blots. Western blotting using capillary electrophoresis shows promise to analyze low volume samples with reduced reagents and time, while retaining the information content of a typical Western blot.

Anderson, Gwendolyn J.; Cipolla, Cynthia; Kennedy, Robert T.

2011-01-01

102

A 9-vinyladenine-based molecularly imprinted polymeric membrane for the efficient recognition of plant hormone 1H-indole-3-acetic acid  

Microsoft Academic Search

9-Vinyladenine was synthesized as a novel functional monomer for molecular imprinting techniques and its structure was established with elemental analysis and 1H NMR spectroscopy. The binding mechanism between this functional monomer 9-vinyladenine and the plant hormone 1H-indole-3-acetic acid in acetonitrile was studied with UV–vis spectrophotometry. Based on this study, using 1H-indole-3-acetic acid as a template molecule, a specific 9-vinyladenine-based molecularly

Changbao Chen; Yanjun Chen; Jie Zhou; Chunhui Wu

2006-01-01

103

Reverse Osmosis Membrane Research.  

National Technical Information Service (NTIS)

Studies of cellulose acetate membranes have been concerned mainly with the compaction phenomenon, membrane life, and methods for drying modified membranes. The use of finely divided filler particles in an attempt to improve its resistance to creep has bee...

U. Merten H. K. Lonsdale R. L. Riley K. D. Vos

1968-01-01

104

Variation within serovars of Neisseria gonorrhoeae detected by structural analysis of outer-membrane protein PIB and by pulsed-field gel electrophoresis  

Microsoft Academic Search

Outer-membrane protein PI is the antigen responsible for serovar specificity of Neisseria gonorrhoeae and is a potential vaccine target. In order to investigate possible hidden variation within a serovar, the sequence of the por genes encoding protein PIB have been obtained from a series of strains, including isolates known to be epidemiologically linked. The inferred amino acid sequences of the

Susan J. Cooke; C. La Poh; C. A. Ison; J. E. Heckels

1997-01-01

105

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

106

Determination of binding constants of Ca 2+, Na +, and Cl ? ions to liposomal membranes of dipalmitoylphosphatidylcholine at gel phase by particle electrophoresis  

Microsoft Academic Search

The zeta potentials of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) liposomes were measured at a gel phase as a function of CaCl2 concentration (0–200 mM) in a solution containing different NaCl concentrations (0–200 mM). The data obtained were analyzed with the diffuse double layer theory including the Graham theory. The intrinsic binding constants of ions to DPPC membranes and the distance of the shear

Koichi Satoh

1995-01-01

107

Desalination Pretreatment Using Controlled-Chain PEG-Enhanced Cellulose Acetate Ultrafiltration Membranes. Desalination and Water Purification Research and Development Program Report No. 138.  

National Technical Information Service (NTIS)

In order to reduce hydrophobic interactions between natural organic matter (NOM) and the membrane surface, and thereby fouling due to NOM, hydrophilic poly(ethylene glycol) (PEG) monomer chains were attached to a commercially available membrane via in sit...

I. C. Escobar T. Gullinkala

2008-01-01

108

First evidence of a membrane-bound, tyramine and beta-phenylethylamine producing, tyrosine decarboxylase in Enterococcus faecalis: a two-dimensional electrophoresis proteomic study.  

PubMed

The soluble and membrane proteome of a tyramine producing Enterococcus faecalis, isolated from an Italian goat cheese, was investigated. A detailed analysis revealed that this strain also produces small amounts of beta-phenylethylamine. Kinetics of tyramine and beta-phenylethylamine accumulation, evaluated in tyrosine plus phenylalanine-enriched cultures (stimulated condition), suggest that the same enzyme, the tyrosine decarboxylase (TDC), catalyzes both tyrosine and phenylalanine decarboxylation: tyrosine was recognized as the first substrate and completely converted into tyramine (100% yield) while phenylalanine was decarboxylated to beta-phenylethylamine (10% yield) only when tyrosine was completely depleted. The presence of an aspecific aromatic amino acid decarboxylase is a common feature in eukaryotes, but in bacteria only indirect evidences of a phenylalanine decarboxylating TDC have been presented so far. Comparative proteomic investigations, performed by 2-DE and MALDI-TOF/TOF MS, on bacteria grown in conditions stimulating tyramine and beta-phenylethylamine biosynthesis and in control conditions revealed 49 differentially expressed proteins. Except for aromatic amino acid biosynthetic enzymes, no significant down-regulation of the central metabolic pathways was observed in stimulated conditions, suggesting that tyrosine decarboxylation does not compete with the other energy-supplying routes. The most interesting finding is a membrane-bound TDC highly over-expressed during amine production. This is the first evidence of a true membrane-bound TDC, longly suspected in bacteria on the basis of the gene sequence. PMID:19405032

Pessione, Enrica; Pessione, Alessandro; Lamberti, Cristina; Coïsson, Daniel Jean; Riedel, Kathrin; Mazzoli, Roberto; Bonetta, Silvia; Eberl, Leo; Giunta, Carlo

2009-05-01

109

Metal ion dependence of a heat-modifiable protein from the outer membrane of Escherichia coli upon sodium dodecyl sulfate-gel electrophoresis.  

PubMed Central

One heat-modifiable protein of Escherichia coli outer membrane does not completely change to the high-temperature form in the presence of magnesium ion in sodium dodecyl sulfate solution. When the metal ion complexing reagents ethylenediaminetetraacetic acid, phosphate ion, hydroxyl ion, or the competitive cations Zn2+ or Ca2+ are added to the sodium dodecyl sulfate-solubilized sample of outer membrane, and then the sample is heated to 100 degrees C and recooled to room temperature, the protein is almost completely converted to the high-temperature form. In control samples, or if sodium chloride, magnesium chloride, or manganous chloride are added to these samples and treated the same way, a large amount of the low-temperature form of the protein is preserved. beta-Mercaptoethanol additions gave the same results as the metal ion complexing reagents and may owe its activity in these solutions to metal-binding activity and not to its role as a reducing reagent. We concluded that magnesium ion may be involved with stabilization of the low-temperature form of the protein either by directly binding the magnesium or by mediating interaction with other components of the membrane. Images

McMichael, J C; Ou, J T

1977-01-01

110

Conductive Media for Electrophoresis.  

National Technical Information Service (NTIS)

A series of low molarity conductive media based on non-buffering univalent cations, such as sodium chloride-sodium acetate (SCA), sodium boric acid (SB), lithium boric acid, and lithium acetate mitigate the 'runaway' positive feedback heating loop produce...

J. R. Brody S. E. Kern

2004-01-01

111

Electrophoresis experiments for space  

NASA Astrophysics Data System (ADS)

It has long been hoped that space could alleviate the problems of large-scale, high-capacity electrophoresis. Support media and reduced chamber dimensions of capillary electrophoresis have established the physical boundaries for Earth-based systems. Ideally, electrophoresis conducted in a virtual weightless environment in an unrestricted ``free'' fluid should have great potential. The electrophoresis and isoelectric focusing experiments done in the reduced gravity over the past twenty-five years have demonstrated the absence of thermal convection and sedimentation as well as the presence of electrohydrodynamics that requires careful control. One commercial venture produced gram amounts of an electrophoretically purified protein during seven Space Shuttle flights but the market disappeared in the six years between experiment conception and performance on the Space Shuttle. Our accumulated experience in microgravity plus theoretical models predict improvements that should be possible with electrophoresis if past problems are considered and both invention of new technologies and innovation of procedures on the Space Station are encouraged. .

Snyder, Robert S.; Rhodes, Percy H.

2000-01-01

112

Synthesis and characterization of cellulose acetate-polysulfone blend microfiltration membrane for separation of microbial cells from lactic acid fermentation broth  

Microsoft Academic Search

This work is focused on synthesis and characterization of a polymer blend microfiltration membrane for separation of microbial cells from lactic acid fermentation broth in a continuous process. The membranes were prepared by blending hydrophilic cellulose diacetate (CA) polymer with hydrophobic polysulfone (PSF) polymer in wet phase inversion method. Polymers were blended in N-methyl-2-pyrrolidone (NMP) solvent (70wt.%) where polyethylene glycol

J. Sikder; C. Pereira; S. Palchoudhury; K. Vohra; D. Basumatary; P. Pal

2009-01-01

113

Measuring Genetic Variation in Zebra Mussels Using Acetate Electrophoresis  

NSDL National Science Digital Library

This resource is a mini-workshop for instructing a laboratory exercise in genetics and evolutionary biology. Students learn concepts of genetic variability and equilibria in natural populations. This resource can be used to organize laboratory exercises for classes in genetics and evolutionary biology.

Corey A Goldman (University of Toronto;)

1998-01-01

114

The Role of Electrophoresis in Gene Electrotransfer  

Microsoft Academic Search

Gene electrotransfer is an established method for gene delivery which uses high-voltage pulses to increase the permeability\\u000a of a cell membrane and enables transfer of genes. Poor plasmid mobility in tissues is one of the major barriers for the successful\\u000a use of gene electrotransfer in gene therapy. Therefore, we analyzed the effect of electrophoresis on increasing gene electrotransfer\\u000a efficiency using

M. Pavlin; K. Flisar; M. Kandušer

2010-01-01

115

Capillary Electrophoresis of Bacterial (Lipo)Polysaccharides  

Microsoft Academic Search

\\u000a Lipopolysaccharides (LPSs) are major components of the outer ­membrane of gram-negative bacteria, and, along with some acidic\\u000a polysaccharides, are important macromolecules belonging to bacteria. The recent emergence of modern ­analytical tools for\\u000a their study has produced a virtual explosion in the field of glycomics. Capillary electrophoresis (CE), due to its high resolving\\u000a power and sensitivity, has been useful in the

Nicola Volpi; Francesca Maccari

116

Electrophoresis in space.  

PubMed

Programs for free flow electrophoresis in microgravity over the past 25 years are reviewed. Several studies accomplished during 20 spaceflight missions have demonstrated that sample throughput is significantly higher in microgravity than on the ground. Some studies have shown that resolution is also increased. However, many cell separation trials have fallen victim to difficulties associated with experimenting in the microgravity environment such as microbial contamination, air bubbles in electrophoresis chambers, and inadequate facilities for maintaining cells before and after separation. Recent studies suggest that the charge density of cells at their surface may also be modified in microgravity. If this result is confirmed, a further cellular mechanism of "sensing" the low gravity environment will have been found. Several free fluid electrophoresis devices are now available. Most have been tried at least once in microgravity. Newer units not yet tested in spaceflight have been designed to accommodate problems associated with space processing. The USCEPS device and the Japanese FFEU device are specifically designed for sterile operations, whereas the Octopus device is designed to reduce electroosmotic and electrohydrodynamic effects, which become dominant and detrimental in microgravity. Some of these devices will also separate proteins by zone electrophoresis, isotachophoresis, or isoelectric focusing in a single unit. Separation experiments with standard test particles are useful and necessary for testing and optimizing new space hardware. A cohesive free fluid electrophoresis program in the future will obviously require (1) flight opportunities and funding, (2) identification of suitable cellular and macromolecular candidate samples, and (3) provision of a proper interface of electrophoresis processing equipment with biotechnological facilities--equipment like bioreactors and protein crystal growth chambers. The authors feel that such capabilities will lead to the production of commercially useful quantities of target products and to an accumulation of new knowledge relating to the complexities of electrostatic phenomena at the cell surface. PMID:10660776

Bauer, J; Hymer, W C; Morrison, D R; Kobayashi, H; Seaman, G V; Weber, G

1999-01-01

117

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

118

DNA ELECTROPHORESIS AT SURFACES  

SciTech Connect

During this year we performed two major projects: I. We developed a detailed theoretical model which complements our experiments on surface DNA electrophoresis. We found that it was possible to enhance the separation of DNA chains by imposing a chemical nanoscale pattern on the surface. This approach utilized the surface interaction effect of the DNA chains with the substrate and is a refinement to our previous method in which DNA chains were separated on homogeneous flat surfaces. By introducing the nano-patterns on the surface, the conformational changes of DNA chains of different lengths can be amplified, which results in the different friction strengths with the substrate surface. Our results also show that, when compared to the DNA electrophoresis performed on homogeneous flat surfaces, nanopatterned surfaces offer a larger window in choosing different surface interactions to achieve separation. II. In collaboration with a large international manufacturer of skin care products we also embarked on a project involving photo toxicity of titanium dioxide nanoparticles, which are a key ingredient in sunscreen and cosmetic lotions. The results clearly implicated the nanoparticles in catalyzing damage to chromosomal DNA. We then used this knowledge to develop a polymer/anti-oxidant coating which prevented the photocatalytic reaction on DNA while still retaining the UV absorptive properties of the nanoparticles. The standard gel electrophoresis was not sufficient in determining the extent of the DNA damage. The conclusions of this study were based predominantly on analysis obtained with the surface electrophoresis method.

RAFAILOVICH, MIRIAM; SOKOLOV, JONATHAN; GERSAPPE, DILIP

2003-09-01

119

Nonaqueous capillary electrophoresis  

Microsoft Academic Search

The benefits of non-aqueous capillary electrophoresis have been described in a number of recent publications. The wide selection of organic solvents, with their very different physicochemical properties, broadens our scope to manipulate separation selectivity. The lower currents present in non-aqueous solvents allow the use of high electric field strengths and wide bore capillaries, the latter in turn allowing larger sample

Marja-Liisa Riekkola; Matti Jussila; Simo P Porras; István E Valkó

2000-01-01

120

Cationic electrophoresis and eastern blotting.  

PubMed

Denaturing, discontinuous electrophoresis in the presence of SDS has become a standard method for the protein scientist. However, there are situations where this method produces suboptimal results. In these cases, electrophoresis in the presence of positively charged detergents like cetyltrimethylammonium bromide may work considerably better. Methods for electrophoresis, staining, and blotting of such gels are presented. PMID:19378051

Buxbaum, Engelbert

2009-01-01

121

Segmented field OFFGEL® electrophoresis.  

PubMed

A multielectrode setup for protein OFFGEL electrophoresis that significantly improves protein separation efficiency has been developed. Here, the electric field is applied by segments between seven electrodes connected in series to six independent power supplies. The aim of this strategy is to distribute evenly the electric field along the multiwell system, and as a consequence to enhance electrophoresis in terms of separation time, resolution, and protein collection efficiency, while minimizing the overall potential difference and therefore the Joule heating. The performances were compared to a standard two-electrode setup for OFFGEL fractionation of a protein mixture, using UV-Vis spectroscopy for quantification and MALDI-MS for identification. The electrophoretic separation process was simulated, and optimized by solving the time-dependent Nernst-Planck differential equation. PMID:23086720

Tobolkina, Elena; Cortés-Salazar, Fernando; Momotenko, Dmitry; Maillard, Julien; Girault, Hubert H

2012-10-22

122

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

123

RED Facts: Tridecenyl Acetates.  

National Technical Information Service (NTIS)

This fact sheet summarizes the information in the RED document for reregistration case 4116, tridecenyl acetates. Tridecenyl acetates are sex attractant pheromones used in tomato fields to disrupt the mating behavior of tomato pinworms.

1996-01-01

124

Coordination of Lanthanide Acetates  

SciTech Connect

A study of the structures of hydrated and anhydrous lanthanide acetates by X-ray diffraction, infrared spectra, and absorption spectra demonstrates that there are three separate structures for hydrated lanthanide acetates and four structures for anhydrous acetates. This paper discusses the results of that study.

Karraker, D.G.

2001-08-29

125

Ultra-trace determination of lead(II) in water using electrothermal atomic absorption spectrometry after preconcentration by solid-phase extraction to a small piece of cellulose acetate type membrane filter.  

PubMed

A simple and inexpensive preconcentration technique has been developed for the ultra-trace determination of lead(II) using electrothermal atomic absorption spectrometry (ETAAS). The lead(II) complex with dicyclohexano-18-crown 6-ether (DC18C6) was extracted to a small piece of cellulose acetate-type membrane filter (2 × 5 mm) merely by vigorously eccentric stirring for 120 min under the coexistence of sodium dodecyl sulfate (SDS) at around pH 7. The extraction medium was inserted into a graphite cuvette for the determination of lead(II) by ETAAS. A linear relation was obtained for the range of 0.1-5.0 ng in 10 ml of lead(II) standard solution (r = 0.998). The detection limit was found to be 0.03 ng of lead(II) in 10 ml (0.003 µg l(-1)) of water sample. The proposed method was applied to the ultra-trace determination of lead(II) in river water, underground water, tap water, and snow fall samples. PMID:21233566

Mizuguchi, Hitoshi; Ishida, Mirai; Takahashi, Tomohiro; Sasaki, Atsushi; Shida, Junichi

2011-01-01

126

Pallidol hexa-acetate ethyl acetate monosolvate  

PubMed Central

The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100?Å) is 54.73?(6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = ?70.24?(14), ?114.43?(10) and ?72.54?(13)°]. In the crystal, a three-dimensional architecture is sustained by C—H?O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside.

Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

127

Multiplexed capillary electrophoresis system  

DOEpatents

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

Yeung, Edward S. (Ames, IA); Chang, Huan-Tsang (Silver Spring, MD); Fung, Eliza N. (Ames, IA); Li, Qingbo (Ames, IA); Lu, Xiandan (Ames, IA)

1996-12-10

128

Multiplexed capillary electrophoresis system  

DOEpatents

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

Yeung, Edward S. (Ames, IA); Li, Qingbo (Ames, IA); Lu, Xiandan (Ames, IA)

1998-04-21

129

Study of Mass Transfer in Membrane Processes.  

National Technical Information Service (NTIS)

Electrical potential differences across membranes were measured with both an anion-exchange membrane used in electrodialysis and a modified cellulose acetate membrane used in reverse osmosis. These measurements were performed in special apparatus which on...

K. S. Spiegler

1970-01-01

130

Capillary electrophoresis of methylderivatives of quinolines. I.  

PubMed

Migration behavior of quinoline, isoquinoline and related methylderivatives has been investigated with respect to the influence of running buffer acidity and to the presence of polyethylene glycol (PEG) 2000 as additive. Dissociation constants and ionic mobilities were determined by capillary electrophoresis (CE). Mobility and viscosity measurements in PEG containing buffers show that analyte transport is not in accordance with Walden's rule and microviscosity plays the role in analyte retardation. Variation of pH and PEG concentration provides the optimal conditions for the CE separation of methylquinolines (0.0176 M acetate-Tris buffer, pH 5.5, 10% PEG 2000). Analysis of industrial mixture (isoquinoline fraction from distillation of coal tar) was performed and good agreement with gas chromatographic results was found. PMID:11403484

Bednár, P; Barták, P; Adamovský, P; Gavenda, A; Sevcík, J; Stránsky, Z

2001-05-11

131

The purification of IgY from chicken egg yolk by preparative electrophoresis  

Microsoft Academic Search

Chicken IgY has been purified from egg yolk by preparative electrophoresis on the Gradiflow, a system which has been employed for the purification of a wide range of proteins with high recovery and biological activity. Protein purification on the Gradiflow utilises electrophoresis with selected combinations of porous membranes and buffers. The purification of IgY was achieved by initial PEG lipid

Sarah C Gee; Irene M Bate; Theresa M Thomas; Dennis B Rylatt

2003-01-01

132

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

133

Possibility of Microchip Electrophoresis for Biological Application  

NASA Astrophysics Data System (ADS)

Microchip electrophoresis has recently attracted much attention in the field of nuclear acid analysis due to its high efficiency, ease of operation, low consumption of samples and reagents, and relatively low costs. Nucleic acid fragments are separated by capillary electrophoresis in a chip with microfabricated channels, with automated detection as well as on-line data evaluation. Microfabricated devices are forecast to be fundamental to the postgenome era, especially in the field of genetics and medicine. However, although there are many reports of the use of these instruments to evaluate standard DNA, DNA ladders, PCR products, and commercially available plasmid digests, little information is available their use with biological material. In this report, we showed the accuracy of sizing and quantification of endonuclease-digested plasmid DNA. We also showed the feasibility of on-microchip endonuclease treatment of plasmid DNA and sequential analysis as an additional application for DNA analysis. Furthermore, to evaluate the possibility of microchip electrophoresis for biological application, the results of the examination of blood sugar in human plasma and mitochondrial membrane potential were shown.

Kataoka, Masatoshi; Kido, Jun-Ichi; Shinohara, Yasuo

134

A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti  

Microsoft Academic Search

Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO2 by

Elwood A. Mullins; Julie A. Francois; T. Joseph Kappock

2008-01-01

135

Capillary electrophoresis in clinical chemistry  

Microsoft Academic Search

Since its introduction, capillary electrophoresis has diversified, spreading out into different specialized fields covering solutions for almost any analytical questions arising in research laboratories. In the context of clinical chemistry, results must be provided at low costs and in a clinically relevent time frame; however, the attributes which have made capillary electrophoresis such a successful tool in basic research are

Rainer Lehmann; Wolfgang Voelter; Hartmut M. Liebich

1997-01-01

136

Consequences of membrane protein overexpression in Escherichia coli.  

PubMed

Overexpression of membrane proteins is often essential for structural and functional studies, but yields are frequently too low. An understanding of the physiological response to overexpression is needed to improve such yields. Therefore, we analyzed the consequences of overexpression of three different membrane proteins (YidC, YedZ, and LepI) fused to green fluorescent protein (GFP) in the bacterium Escherichia coli and compared this with overexpression of a soluble protein, GST-GFP. Proteomes of total lysates, purified aggregates, and cytoplasmic membranes were analyzed by one- and two-dimensional gel electrophoresis and mass spectrometry complemented with flow cytometry, microscopy, Western blotting, and pulse labeling experiments. Composition and accumulation levels of protein complexes in the cytoplasmic membrane were analyzed with improved two-dimensional blue native PAGE. Overexpression of the three membrane proteins, but not soluble GST-GFP, resulted in accumulation of cytoplasmic aggregates containing the overexpressed proteins, chaperones (DnaK/J and GroEL/S), and soluble proteases (HslUV and ClpXP) as well as many precursors of periplasmic and outer membrane proteins. This was consistent with lowered accumulation levels of secreted proteins in the three membrane protein overexpressors and is likely to be a direct consequence of saturation of the cytoplasmic membrane protein translocation machinery. Importantly accumulation levels of respiratory chain complexes in the cytoplasmic membrane were strongly reduced. Induction of the acetate-phosphotransacetylase pathway for ATP production and a down-regulated tricarboxylic acid cycle indicated the activation of the Arc two-component system, which mediates adaptive responses to changing respiratory states. This study provides a basis for designing rational strategies to improve yields of membrane protein overexpression in E. coli. PMID:17446557

Wagner, Samuel; Baars, Louise; Ytterberg, A Jimmy; Klussmeier, Anja; Wagner, Claudia S; Nord, Olof; Nygren, Per-Ake; van Wijk, Klaas J; de Gier, Jan-Willem

2007-04-19

137

Electrophoretic Ratchets and Cyclic Electrophoresis.  

National Technical Information Service (NTIS)

Systems and methods for improving the resolution of macromolecules during electrophoresis. A method of creating an electrical field-rectifying fractionation-ratchet includes obtaining a fractionated particle that has an electrophoretic mobility that varie...

A. Basu G. A. Griess J. W. Valvano P. Serwer

2003-01-01

138

DNA typing by capillary electrophoresis  

SciTech Connect

Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

Zhang, N.

1997-10-08

139

Clinical applications of capillary electrophoresis  

Microsoft Academic Search

Capillary electrophoresis (CE) is an extremely sensitive technique, which has been used in the clinical laboratory for almost\\u000a 10 yr. The components of CE instrumentation are described, as are injection modes, buffers, and effects of electroosmotic\\u000a flow. The modes of separation used in CE, namely, capillary zone electrophoresis, capillary isoelectric focusing, capillary\\u000a isotachophoresis, and micellar electrokinetic capillary chromatography, are explained.

M. A. Jenkins

2000-01-01

140

Operation of the CO Dehydrogenase/Acetyl Coenzyme A Pathway in both Acetate Oxidation and Acetate Formation by the Syntrophically Acetate-Oxidizing Bacterium Thermacetogenium phaeum  

PubMed Central

Thermacetogenium phaeum is a homoacetogenic bacterium that can grow on various substrates, such as pyruvate, methanol, or H2/CO2. It can also grow on acetate if cocultured with the hydrogen-consuming methanogenic partner Methanothermobacter thermautotrophicus. Enzyme activities of the CO dehydrogenase/acetyl coenzyme A (CoA) pathway (CO dehydrogenase, formate dehydrogenase, formyl tetrahydrofolate synthase, methylene tetrahydrofolate dehydrogenase) were detected in cell extracts of pure cultures and of syntrophic cocultures. Mixed cell suspensions of T. phaeum and M. thermautotrophicus oxidized acetate rapidly and produced acetate after addition of H2/CO2 after a short time lag. CO dehydrogenase activity staining after native polyacrylamide gel electrophoresis exhibited three oxygen-labile bands which were identical in pure culture and coculture. Protein profiles of T. phaeum cells after sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the strain exhibited basically the same protein patterns in both pure and syntrophic culture. These results indicate that T. phaeum operates the CO dehydrogenase/acetyl-CoA pathway reversibly both in acetate oxidation and in reductive acetogenesis by using the same biochemical apparatus, although it has to couple this pathway to ATP synthesis in different ways.

Hattori, Satoshi; Galushko, Alexander S.; Kamagata, Yoichi; Schink, Bernhard

2005-01-01

141

Acetals and Ketals.  

National Technical Information Service (NTIS)

Thirteen open-chain simple cyclic and spirocyclic acetals and ketals were studied. The synthesis of all the cyclic compounds was accomplished by an alcoholysis reaction. The infrared and proton magnetic resonance spectra were measured and correlated. (Aut...

J. Radell R. E. Rondeau

1970-01-01

142

Sodium Acetate Hand Warmers  

NSDL National Science Digital Library

In this activity, sodium acetate hand warmers are used to introduce learners to supersaturated solutions, crystallization, and exothermic reactions. This activity guide includes background information, extension ideas, and resources.

Johnson, Jill

2006-01-01

143

Modulation of Hyaluronan Synthase Activity in Cellular Membrane Fractions*  

PubMed Central

Hyaluronan (HA), the only non-sulfated glycosaminoglycan, is involved in morphogenesis, wound healing, inflammation, angiogenesis, and cancer. In mammals, HA is synthesized by three homologous HA synthases, HAS1, HAS2, and HAS3, that polymerize the HA chain using UDP-glucuronic acid and UDP-N-acetylglucosamine as precursors. Since the amount of HA is critical in several pathophysiological conditions, we developed a non-radioactive assay for measuring the activity of HA synthases (HASs) in eukaryotic cells and addressed the question of HAS activity during intracellular protein trafficking. We prepared three cellular fractions: plasma membrane, cytosol (containing membrane proteins mainly from the endoplasmic reticulum and Golgi), and nuclei. After incubation with UDP-sugar precursors, newly synthesized HA was quantified by polyacrylamide gel electrophoresis of fluorophore-labeled saccharides and high performance liquid chromatography. This new method measured HAS activity not only in the plasma membrane fraction but also in the cytosolic membranes. This new technique was used to evaluate the effects of 4-methylumbeliferone, phorbol 12-myristate 13-acetate, interleukin 1?, platelet-derived growth factor BB, and tunicamycin on HAS activities. We found that HAS activity can be modulated by post-translational modification, such as phosphorylation and N-glycosylation. Interestingly, we detected a significant increase in HAS activity in the cytosolic membrane fraction after tunicamycin treatment. Since this compound is known to induce HA cable structures, this result links HAS activity alteration with the capability of the cell to promote HA cable formation.

Vigetti, Davide; Genasetti, Anna; Karousou, Evgenia; Viola, Manuela; Clerici, Moira; Bartolini, Barbara; Moretto, Paola; De Luca, Giancarlo; Hascall, Vincent C.; Passi, Alberto

2009-01-01

144

Thin Membranes of Parlodion.  

PubMed

Parlodion membranes 50 to 1000 A A thick have been prepared by deposition of isoamyl acetate solutions on the air-water interface under conditions of controlled evaporation. Capacitance and resistance measurements have established the integrity of large areas of these membranes. The former also provides corroboration of the thickness estimated from the amounts of parlodion deposited. PMID:17742881

Lakshminarayanaiah, N; Shanes, A M

1963-07-01

145

The Use of Cellulose Acetate for the Electrophoretic Separation and Quantitation of Serum Lactic Dehydrogenase Isozymes in Normal and Pathologic States.  

National Technical Information Service (NTIS)

Normal and abnormal lactic dehydrogenase (LDH) isozyme distribution in serum was studied using cellulose acetate electrophoresis with a p-iodonitro tetrazolium violet (INT) stain, and a graphing procedure devised to permit rapid visualization and evaluati...

M. Mager W. F. Blatt W. H. Abelmann

1966-01-01

146

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

147

Preparation and Evaluation of Optimized Hemodialysis Membranes.  

National Technical Information Service (NTIS)

The means to fabricate dialysis membranes from cellulose acetate, both in the laboratory and on a pilot production scale, have been established, and a demonstration run has been carried out. These membranes are characterized by excellent uniformity, high ...

F. S. Model H. J. Davis P. A. Sessa

1973-01-01

148

Preparation and Evaluation of Optimized Hemodialysis Membranes.  

National Technical Information Service (NTIS)

Characterization of the initial cellulose acetate (CA) production membrane has been completed and confirms that this membrane possesses dramatic dialysis permeability advantages over cellulose in the middle molecule region. A preliminary economic projecti...

F. S. Model H. J. Davis P. A. Sessa

1973-01-01

149

Membrane Processes (Osmosis and Reverse Osmosis).  

National Technical Information Service (NTIS)

Previous work on the general problem of making more productive reverse osmosis membranes resulted in new classes of porous cellulose acetate reverse osmosis membranes for low pressure work of highly increased (100%) productivities, as well as in a new con...

B. Kunst G. Arneri P. Goran A. M. Basnec

1973-01-01

150

RNA separation by in-capillary denaturing polymer electrophoresis with 1,2,5-thiadiazole as an additive.  

PubMed

1,2,5-Thiadiazole improved RNA separation with in-capillary denaturing polymer electrophoresis. 1,2,5-Thiadiazole was synthesized as an extraction solvent substituted for a halogenated solvent. While 1,2,5-thiadiazole was an excellent extraction solvent and an environmentally friendly solvent, we found that 1,2,5-thiadiazole was a strong hydrophobic compound for RNA and the RNA separation performance by in-capillary denaturing polymer electrophoresis was dramatically improved. We suggest "in-capillary denaturing polymer electrophoresis" as an RNA separation that realizes the denaturing and separation simultaneously. RNA separation by the method required a strong denaturant, acetic acid, to cleave the intramolecular hydrogen. The running buffer containing acetic acid was of high conductivity and low pH, in which the condition introduced Joule heating and low sensitivity. While conventional denaturants, formaldehyde and urea, maintained small electric conductivity and neutral pH, these denaturants were too weak to achieve the RNA separation by in-capillary denaturing polymer electrophoresis. 1,2,5-Thiadiazole being a neutral molecule, both conductivity and buffer pH were able to be adjusted to a desirable strength for RNA separation. In this paper, we report that RNA separation by in-capillary denaturing polymer electrophoresis in neutral pH was achieved and the sensitivity for RNA separation was higher than that for RNA separation by in-capillary denaturing polymer electrophoresis with acetic acid. PMID:21953997

Sumitomo, Keiko; Yamaguchi, Yoshinori; Tatsuta, Kuniaki

2011-09-23

151

Introduction to Agarose Gel Electrophoresis  

NSDL National Science Digital Library

In this module, developed as part of Cornell's Learning Initiative in Medicine and Bioengineering (CLIMB), students are introduced to the concepts of gel electrophoresis without requiring all the equipment needed to run a full gel electrophoresis experiment. The goal is to have students understand how gels are made for DNA separation and how altering the composition can affect the experimental parameters. This module contains a teacher's guide, classroom activity, and suggestions for extended activities. This lab is a precursor to Cornellâs Institute for Biology Teachers labâs entitled DNA Profiling â Paternity Testing, which is linked within the teacher's guide. CLIMB is part of the NSF GK-12 program.

Bioengineering, Climb: C.

152

Contactless conductivity detector for microchip capillary electrophoresis.  

PubMed

A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices. PMID:12033293

Pumera, Martin; Wang, Joseph; Opekar, Frantisek; Jelínek, Ivan; Feldman, Jason; Löwe, Holger; Hardt, Steffen

2002-05-01

153

Polyaniline Membranes for Separation Applications.  

National Technical Information Service (NTIS)

High quality membranes of poly aniline/ethylaniline copolymers along with polyaniline/polyimide blends have been synthesized. Water permeates preferentially over organic (such as acetic acid) through doped poly aniline due to a combination of favorable di...

R. B. Kaner

1997-01-01

154

Fragrance material review on phenethyl acetate.  

PubMed

A toxicologic and dermatologic review of phenethyl acetate when used as a fragrance ingredient is presented. Phenethyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for phenethyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, toxicokinetics, repeated dose, genotoxicity, and carcinogenicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414644

McGinty, D; Vitale, D; Letizia, C S; Api, A M

2012-03-05

155

Fragrance material review on ?-methylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of ?-methylbenzyl acetate when used as a fragrance ingredient is presented. ?-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for ?-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, and repeated dose data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22406576

McGinty, D; Letizia, C S; Api, A M

2012-03-03

156

Fragrance material review on piperonyl acetate.  

PubMed

A toxicologic and dermatologic review of piperonyl acetate when used as a fragrance ingredient is presented. Piperonyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for piperonyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, toxicokinetics, and genotoxicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22445840

McGinty, D; Letizia, C S; Api, A M

2012-03-15

157

Fragrance material review on 2-phenylpropyl acetate.  

PubMed

A toxicologic and dermatologic review of 2-phenylpropyl acetate when used as a fragrance ingredient is presented. 2-Phenylpropyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22421639

McGinty, D; Letizia, C S; Api, A M

2012-03-06

158

Transient translocation of hemidesmosomal bullous pemphigoid antigen 1 from cytosol to membrane fractions by 12- O-tetradecanoylphorbol-13-acetate treatment and Ca 2+-switch in a human carcinoma cell line  

Microsoft Academic Search

We previously showed that 12-O-tetradecanoylphorbol-13-acetate (TPA) and Ca2+-switch from low (0.07 mM) to normal (1.87 mM) concentration in culture medium, which were also linked to activation of protein kinase C (PKC), lead to phosphorylation of 180 kDa-bullous pemphigoid antigen (BPAG) 2, but not of 230 kDa-BPAG1, and possibly to its disassembly from hemidesmosomes in a human squamous cell carcinoma cell

Yuriko Matsuoka; Takahiro Yamada; Mariko Seishima; Yoshiaki Hirako; Katsushi Owaribe; Yasuo Kitajima

2001-01-01

159

Identification and characterization of stable membrane protein complexes  

Microsoft Academic Search

Many membrane proteins exist as oligomers. Such oligomers play an important role in a broad variety of cellular processes such as ion transport, energy transduction, osmosensing and cell wall synthesis. We developed an electrophoresis-based method of identifying oligomeric membrane proteins that are stable in SDS-based electrophoresis but become dissociated upon exposure to small alcohols. When this method was applied to

R. E. J. Spelbrink

2007-01-01

160

Strain typing of acetic acid bacteria responsible for vinegar production by the submerged elaboration method  

Microsoft Academic Search

Strain typing of 103 acetic acid bacteria isolates from vinegars elaborated by the submerged method from ciders, wines and spirit ethanol, was carried on in this study. Two different molecular methods were utilised: pulsed field gel electrophoresis (PFGE) of total DNA digests with a number of restriction enzymes, and enterobacterial repetitive intergenic consensus (ERIC) – PCR analysis. The comparative study

Rocío Fernández-Pérez; Carmen Torres; Susana Sanz; Fernanda Ruiz-Larrea

2010-01-01

161

Oxime Acetates: Substrates for Acetylcholinesterase.  

National Technical Information Service (NTIS)

Oxime acetates function as typical substrates for acetylcholinesterase (AChE). Both syn 3- and syn 4-PAM acetates are rapidly hydrolyzed. Both are highly water soluble and give large changes in molar absorbance upon hydrolysis. Hence, they have potential ...

G. M. Steinberg J. P. Maddox L. J. Szafraniec L. M. Berkowitz N. C. Thomas

1971-01-01

162

Kallolide A acetate pyrazoline  

PubMed Central

In the crystal structure of kallolide A acetate pyrazoline [systematic name: 7-methyl-16-oxo-4,10-bis­(prop-1-en-2-yl)-17,18-dioxa-14,15-diaza­tetra­cyclo­[9.4.2.16,9.01,12]octa­deca-6,8,14-trien-5-yl acetate], C23H28N2O5, there is a 12-member­ed carbon macrocyclic structure. In addition, there is a tris­ubstituted furan ring, an approximately planar ?-lactone ring [maximum deviation of 0.057?(3)?Å] and a pyraz­oline ring, the latter in an envelope conformation. The pyrazoline and the ?-lactone rings are fused in a cis configuration. In the crystal, mol­ecules are linked by weak C—H?O inter­actions, forming a two-dimensional network parallel to (001). An intra­molecular C—H?O hydrogen bond is also present.

Rodriguez-Escudero, Idaliz; Marrero, Jeffrey; Rodriguez, Abimael D.

2012-01-01

163

Plasma acetate turnover and oxidation.  

PubMed Central

Plasma acetate turnover and oxidation were determined in 11 healthy subjects by the constant infusion of a trace amount of [1-14C]acetate for 6 h. The subjects ages ranged from 22 to 57 yr. There was a positive correlation (P less than 0.001) between plasma acetate concentration and turnover rate, and a negative correlation (P less than 0.001) between turnover and age. The plasma acetate concentration in the subjects 22--28 yr old was 0.17 vs. 0.13 mM (P less than 0.02) in subjects 40--57 yr old. The plasma acetate turnover rate was also greater in the younger age group (8.23 +/- 0.66 vs. 4.98 +/- 0.64 mumol/min . kg, P less than 0.01). Approximately 90% of the plasma acetate turnover was immediately oxidized to CO2 in both age groups, however, 13.2 +/- 0.89% of the CO2 output in the younger group was derived from plasma acetate oxidation compared to 7.9 +/- 0.94% in the older group (P less than 0.01). The mean plasma acetate concentration, turnover, and oxidation in six cancer patients 47--63 yr old were similar to the values observed in the age-matched healthy subjects. Uptake or output of acetate by various tissues was measured by arterial-venous plasma acetate concentration differences. In seven of eight subjects undergoing elective surgery, the arterial-portal venous concentration difference was negative, which indicated that the gastrointestinal tract can contribute to plasma acetate production. Uptake of plasma acetate by both the leg and liver appeared to be dictated by the arterial acetate concentration. Net production of acetate by both the leg and liver was most often observed at arterial plasma acetate concentrations less than 0.08 mM.

Skutches, C L; Holroyde, C P; Myers, R N; Paul, P; Reichard, G A

1979-01-01

164

DNA Sequencing by Capillary Electrophoresis  

PubMed Central

Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA sequencing methods have evolved from the labor intensive slab gel electrophoresis, through automated multicapillary electrophoresis systems using fluorophore labeling with multispectral imaging, to the “next generation” technologies of cyclic array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes was only possible by the advent of modern sequencing technologies that was a result of step by step advances with a contribution of academics, medical personnel and instrument companies. While next generation sequencing is moving ahead at break-neck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of capillary electrophoresis in DNA sequencing based in part of several of our articles in this journal.

Karger, Barry L.; Guttman, Andras

2009-01-01

165

[Erythrocyte membrane proteins].  

PubMed

Proteins are important constituents of the red blood cell plasma membrane. Several important breakthroughs have occurred in their analysis over the past few years. SDS-polyacrylamide gel electrophoresis lead to the separation of the major proteins and glycoproteins. Location of most of these proteins -- either on the external, the internal or both surfaces of the membrane -- was determined. The strenght of the binding of the protein to the membrane was established. Hydrophobicity of membrane proteins has so far hindered their purification. However, the major glycoprotein (glycophorin A) was isolated and recently sequenced. The description of several membrane-associated enzyme activities has been followed by some understanding of their specific role in the red blood cell physiology. Abnormalities of glycoproteins, Ca2+-ATPase and of membrane protein phosphorylation have been reported under various conditions: sickle cell disease, hereditary spherocytoses, progressive muscular dystrophy. PMID:146451

Delaunay, J

1977-01-01

166

Gas separation membranes  

DOEpatents

A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

Schell, William J. (Long Beach, CA)

1979-01-01

167

Changes in Phospholipid Composition Studied by HPLC and Electric Properties of Liver Cell Membrane of Ethanol-Poisoned Rats  

PubMed Central

Ethanol introduced into the organism undergoes rapid metabolism to acetaldehyde and then to acetic acid. The process is accompanied by formation of reactive oxygen species (ROS), which damage mainly lipids of membrane cells. The effects of ROS can be neutralized by administering preparations with antioxidant properties. The natural preparations of this kind are teas. This paper reports data on the effect of green and black tea on the surface charge density, content of phospholipids, and level of lipid peroxidation products of liver cell membrane of rats chronically intoxicated with ethanol. Surface charge density of liver cells was measured by the electrophoresis method, whereas qualitative phospholipid composition was determined by the HPLC method. Ethanol administration caused an increase in the amount of all phospholipids, in surface charge density as well as in lipid peroxidation products. Ingestion of green and black tea with ethanol partially prevented these ethanol-induced changes, and the action of green tea was stronger than that of black tea.

Szachowicz-Petelska, Barbara; Dobrzynska, Izabela; Skrzydlewska, Elzbieta; Figaszewski, Zbigniew A.

2008-01-01

168

The clinical use of PET with 11C-acetate  

PubMed Central

The aim of this review is to evaluate clinical applications of 11C-acetate positron emission tomography (PET). Acetate is quickly metabolized into acetyl-CoA in human cells. In this form it can either enter into the tricarboxylic acid cycle, thus producing energy, as happens in the myocardium, or participate in cell membrane lipid synthesis, as happens in tumor cells. 11C-acetate PET was originally employed in cardiology, to study myocardial oxygen metabolism. More recently it has also been used to evaluate myocardial perfusion, as well as in oncology. The first studies of 11C-acetate focused on its use in prostate cancer. Subsequently, 11C-acetate was studied in other urological malignancies, as well as renal cell carcinoma and bladder cancer. Well differentiated hepatocellular carcinoma represents an 18F-fluoro-deoxyglucose (18F-FDG) PET pitfall, so many authors have proposed to use 11C-acetate in addition to 18F-FDG in studying this tumor. 11C-acetate PET has also been used in other malignancies, such as brain tumors and lung carcinoma. Some authors reported a few cases in which 11C-acetate PET incidentally found multiple myeloma or rare tumors, such as thymoma, multicentric angiomyolipoma of the kidney and cerebellopontine angle schwannoma. Lastly, 11C-acetate PET was also employed in a differential diagnosis case between glioma and encephalitis. The numerous studies on 11C-acetate have demonstrated that it can be used in cardiology and oncology with no contraindications apart from pregnancy and the necessity of a rapid scan. Despite its limited availability, this tracer can surely be considered to be a promising one, because of its versatility and capacity to even detect non 18F-FDG-avid neoplasm, such as differentiated lung cancer or hepatocellular carcinoma.

Grassi, Ilaria; Nanni, Cristina; Allegri, Vincenzo; Morigi, Joshua James; Montini, Gian Carlo; Castellucci, Paolo; Fanti, Stefano

2012-01-01

169

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

170

Acetate oxidation by syntrophic association between Geobacter sulfurreducens and a hydrogen-utilizing exoelectrogen.  

PubMed

Anodic microbial communities in acetate-fed microbial fuel cells (MFCs) were analyzed using stable-isotope probing of 16S rRNA genes followed by denaturing gradient gel electrophoresis. The results revealed that Geobacter sulfurreducens and Hydrogenophaga sp. predominated in the anodic biofilm. Although the predominance of Geobacter sp. as acetoclastic exoelectrogens in acetate-fed MFC systems has been often reported, the ecophysiological role of Hydrogenophaga sp. is unknown. Therefore, we isolated and characterized a bacterium closely related to Hydrogenophaga sp. (designated strain AR20). The newly isolated strain AR20 could use molecular hydrogen (H2), but not acetate, with carbon electrode as the electron acceptor, indicating that the strain AR20 was a hydrogenotrophic exoelectrogen. This evidence raises a hypothesis that acetate was oxidized by G. sulfurreducens in syntrophic cooperation with the strain AR20 as a hydrogen-consuming partner in the acetate-fed MFC. To prove this hypothesis, G. sulfurreducens strain PCA was cocultivated with the strain AR20 in the acetate-fed MFC without any dissolved electron acceptors. In the coculture MFC of G. sulfurreducens and strain AR20, current generation and acetate degradation were the highest, and the growth of strain AR20 was observed. No current generation, acetate degradation and cell growth occurred in the strain AR20 pure culture MFC. These results show for the first time that G. sulfurreducens can oxidize acetate in syntrophic cooperation with the isolated Hydrogenophaga sp. strain AR20, with electrode as the electron acceptor. PMID:23486252

Kimura, Zen-ichiro; Okabe, Satoshi

2013-03-14

171

Sorption and longitudinal swelling kinetic behaviour in the system cellulose acetate-methanol  

Microsoft Academic Search

The kinetics of methanol vapour sorption and concurrent longitudinal swelling of cellulose acetate membranes has been studied and interpreted in terms of ‘viscous’ swelling and differential swelling stress effects, on the basis of previous modelling work. The close parallelism of the kinetic behaviour observed here and in a previous study of the cellulose acetate-acetone system, shows that both sorption and

M. Sanopoulou; J. H. Petropoulos

1997-01-01

172

Electromigration dispersion in capillary electrophoresis.  

PubMed

In a previous paper (Ghosal and Chen in Bull. Math. Biol. 72:2047, 2010), it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger's equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper, it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data. PMID:22147104

Chen, Zhen; Ghosal, Sandip

2011-12-07

173

Integrated multiplexed capillary electrophoresis system  

DOEpatents

The present invention provides an integrated multiplexed capillary electrophoresis system for the analysis of sample analytes. The system integrates and automates multiple components, such as chromatographic columns and separation capillaries, and further provides a detector for the detection of analytes eluting from the separation capillaries. The system employs multiplexed freeze/thaw valves to manage fluid flow and sample movement. The system is computer controlled and is capable of processing samples through reaction, purification, denaturation, pre-concentration, injection, separation and detection in parallel fashion. Methods employing the system of the invention are also provided.

Yeung, Edward S. (Ames, IA); Tan, Hongdong (Ames, IA)

2002-05-14

174

Antigenic distinctions of glycoproteins in plasma and mitochondrial membranes of lymphoid cells neoplastically transformed by simian virus 40.  

PubMed Central

Highly purified plasma membranes from hamster lymphocytes transformed by simian virus 40 (GD 248) were compared with the membranes of normal cells by crossed immune electrophoresis, crossed-line immune electrophoresis, and bidimensional isoelectric focusing-immune electrophoresis. Antiserum raised by inoculation of guinea pigs with GD 248 membranes was used as serologic reagent, either directly or after absorption with membranes from normal cells. Bidimensional immune electrophoresis reveals the presence in the plasma membranes of GD 248 cells of at least three antigens not detectable in the membranes from the normal cell population. At least two of these are also present in the mitochondrial membranes of GD 248 cells, but none could be detected in membranes of embryonic fibroblasts. Bidimensional isoelectric focusing-immune electrophoresis indicates that the distinctive antigens of the GD 248 membranes are glycoproteins. Images

Schmidt-Ullrich, R; Thompson, W S; Wallach, D F

1977-01-01

175

Membranes and Films from Polymers.  

ERIC Educational Resources Information Center

|Provides background information on polymeric films and membranes including production methods, special industrial and medical applications, laboratory preparation, and an experimental investigation of a porous cellulose acetate membrane. Presents a demonstration to distinguish between high- and low-density polyethylene. (JM)|

Blumberg, Avrom A.

1986-01-01

176

A NEW METHOD FOR THE PREPARATION OF RAT LIVER LYSOSOMES: Separation of Cell Organelles of Rat Liver by Carrier-Free Continuous Electrophoresis  

Microsoft Academic Search

A combination of differential centrifugation and carrier-free continuous electrophoresis is introduced as a new method for the isolation of animal cell organelles .Various buffers were systematically checked in order to find the system which preserves the organelles and gives as well a good separation in the free-flow electrophoresis apparatus . Triethanol- amine-acetate buffer (10 mm), pH 7 .4 was used

R. Stahn; K.-P. MAIER; K. HANNIG

1970-01-01

177

Acetate metabolism in Methanosarcina barkeri  

Microsoft Academic Search

Methanosarcina barkeri was grown by acetate fermentation in complex medium (N2 gas phase). The molar growth yield was 1.6–1.9 g cells\\/mol methane formed. Under these conditions 63–82% of the methane produced byMethanosarcina strains was derived from the methyl carbon of acetate, indicating that some methane was derived from other media components. Growth was not demonstrated in complex media lacking acetate

P. J. Weimer; J. G. Zeikus

1978-01-01

178

Effect of surface roughness of hollow fiber membranes with gear-shaped structure on membrane fouling by sodium alginate  

Microsoft Academic Search

In this work, the relationship between surface roughness of the membrane and membrane fouling was investigated with sodium alginate which is a kind of extracellular polymeric substances (EPS) and is regarded as a main foulant in membrane bioreactor (MBR). Cellulose acetate butyrate polymer which is superior in heat-resistance and mechanical strength was used as membrane material. The membranes having the

Masatoshi Hashino; Takeshi Katagiri; Noboru Kubota; Yoshikage Ohmukai; Tatsuo Maruyama; Hideto Matsuyama

2011-01-01

179

DNA electrophoresis in a monodisperse porous medium.  

PubMed

Electrophoresis of DNA migrating in an ordered matrix is studied and compared with classical agarose gel electrophoresis. A well-defined migration medium is obtained by crystallization of monodisperse silica spheres. Electrophoretic mobility of DNA is measured with fluorescence recovery after photobleaching experiments. The main result is that, as it was the case for gel electrophoresis, diffusion and electrophoretic mobility of DNA in such a medium are well described with reptation theories. PMID:11088923

Meistermann, L; Tinland, B

2000-09-01

180

DNA Sequencing Using capillary Electrophoresis  

SciTech Connect

The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other application papers of sequencing up to this level were also published in the mid 1990's. A major interest of the sequencing community has always been read length. The longer the sequence read per run the more efficient the process as well as the ability to read repeat sequences. We therefore devoted a great deal of time to studying the factors influencing read length in capillary electrophoresis, including polymer type and molecule weight, capillary column temperature, applied electric field, etc. In our initial optimization, we were able to demonstrate, for the first time, the sequencing of over 1000 bases with 90% accuracy. The run required 80 minutes for separation. Sequencing of 1000 bases per column was next demonstrated on a multiple capillary instrument. Our studies revealed that linear polyacrylamide produced the longest read lengths because the hydrophilic single strand DNA had minimal interaction with the very hydrophilic linear polyacrylamide. Any interaction of the DNA with the polymer would lead to broader peaks and lower read length. Another important parameter was the molecular weight of the linear chains. High molecular weight (> 1 MDA) was important to allow the long single strand DNA to reptate through the entangled polymer matrix. In an important paper, we showed an inverse emulsion method to prepare reproducibility linear polyacrylamide polymer with an average MWT of 9MDa. This approach was used in the polymer for sequencing the human genome. Another critical factor in the successful use of capillary electrophoresis for sequencing was the sample preparation method. In the Sanger sequencing reaction, high concentration of salts and dideoxynucleotide remained. Since the sample was introduced to the capillary column by electrokinetic injection, these salt ions would be favorably injected into the column over the sequencing fragments, thus reducing the signal for longer fragments and hence reading read length. In two papers, we examined the role of individual components from the sequencing reaction and then developed a protocol to reduce the deleterio

Dr. Barry Karger

2011-05-09

181

[Nomegestrol acetate: clinical pharmacology].  

PubMed

Progestogens are used in clinical practice in some conditions. Their effects depend on their chemical structure, pharmacokinetics, pharmacodynamics, with important differences among various progestogens. Generally, progestins are classified according to their parent molecule, of which often they keep some features. Derivatives of 19-nor-progesterone are characterized by high selectivity of action on progestin receptor. In particular, nomegestrol acetate (NomAc) shows an important progestational potency, neutral gluco-lipid profile, and antigonadotropic activity. It is used for treating menstrual cycle disorders and for hormone replacement therapy in menopause in association with an estrogen. In future, thanks to its antigonadotropic activity, NomAc will be used in estroprogestin combinations in fertile women, thus taking advantage of its tolerability profile and obtaining numerous non-contraceptive benefits as well. PMID:19749678

Lello, S

2009-10-01

182

Further development of an electroosmotic medium pump system for preparative disk gel electrophoresis  

Microsoft Academic Search

A simple and practical 6.8-cm-diameter (36.30-cm2 cross-sectional-area) preparative disk gel electrophoresis device, based on the design of M. Hayakawa et al. (Anal. Biochem. 288 (2001) 168), in which the elution buffer is driven by an electroosmotic buffer flow through the membrane into the elution chamber from the anode chamber was constructed. We have found that the dialysis membranes employed provide

Mitsuo Hayakawa; Yumiko Hosogi; Hisashi Takiguchi; Teruaki Shiroza; Yasuko Shibata; Koichi Hiratsuka; Michiko Kiyama-Kishikawa; Susumu Hamajima; Yoshimitsu Abiko

2003-01-01

183

Investigation of the spatial relationships between photosystem 2 polypeptides by reversible crosslinking and diagonal electrophoresis  

Microsoft Academic Search

Nearest neighbour relationships within the LHC2-PS2 complex were investigated by using the reversible crosslinking agent dithiobis(succinimidyl propionate) (DSP). This was accomplished by treating PS2-enriched membranes, prepared from chloroplasts of Pisum sativum, with the crosslinker followed by diagonal electrophoresis of the solubilised polypeptides.

P. A. Millner; G. Gogel; J. Barber

1987-01-01

184

Charge Shift Electrophoresis: Simple Method for Distinguishing between Amphiphilic and Hydrophilic Proteins in Detergent Solution  

Microsoft Academic Search

Seventeen hydrophilic proteins and five amphiphilic membrane proteins were subjected to agarose gel electrophoresis in the presence of a nonionic detergent (Triton X-100), a mixture of a nonionic and an anionic detergent (Triton X-100 and sodium deoxycholate), and a mixture of a nonionic and a cationic detergent (Triton X-100 and cetyltrimethylammonium bromide). The electrophoretic mobility of the hydrophilic proteins was

Ari Helenius; Kai Simons

1977-01-01

185

EXTRACTION METHODS FOR ANALYSIS OF CITRUS LEAF PROTEINS BY TWO-DIMENSIONAL GEL ELECTROPHORESIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A general procedure for two-dimensional (2-D) gel electrophoresis of Citrus leaves has been developed. We evaluated the resolution of 2-D protein patterns for Tris-HCl and KCl extractions of water soluble proteins and a phenol extraction for extraction of hydrophobic cell membrane proteins from Cha...

186

Thermogravimetric analysis of the relationship among calcium magnesium acetate, calcium acetate and magnesium acetate  

Microsoft Academic Search

Thermal decomposition characteristic of calcium magnesium acetate (CMA), calcium acetate (CA) and magnesium acetate (MA) are investigated through thermogravimetric (TG) analysis at the heating rates of 5Kmin?1, 7.5Kmin?1, 10Kmin?1 and 15Kmin?1. After dehydration, the evaporation of carboxylic radical and carbon dioxide of CMA and CA exist in two separate segments, but for MA, this occurs together in just one segment

Shengli Niu; Kuihua Han; Chunmei Lu; Rongyue Sun

2010-01-01

187

Molecular Backwash for Decontamination and Rejuvenation of Membranes.  

National Technical Information Service (NTIS)

In studies of osmotic and electroosmotic backwash to decontaminate hyperfiltration membranes, it was found that the direction and magnitude of electroosmotic flow in asymmetric cellulose-acetate membranes in sodium-chloride solutions depends on the concen...

K. S. Spegler

1978-01-01

188

Probing the Electrostatic Shielding of DNA with Capillary Electrophoresis  

PubMed Central

The free solution mobility of a 20-bp double-stranded DNA oligomer has been measured in diethylmalonate (DM) and Tris-acetate buffers, with and without added NaCl or TrisCl. DM buffers have the advantage that the buffering ion is anionic, so the cation composition in the solution can be varied at will. The results indicate that the free solution mobility of DNA decreases linearly with the logarithm of ionic strength when the ionic strength is increased by increasing the buffer concentration. The mobility also decreases linearly with the logarithm of ionic strength when NaCl is added to NaDM buffer or TrisCl is added to TrisDM buffer. Nonlinear effects are observed if the counterion in the added salt differs from the counterion in the buffer. The dependence of the mobility on ionic strength cannot be predicted using the Henry, Debye-Hückel-Onsager, or Pitts equations for electrophoresis. However, the mobilities observed in all buffer and buffer/salt solutions can be predicted within ?20% by the Manning equation for electrophoresis, using no adjustable parameters. The results suggest that the electrostatic shielding of DNA is determined not only by the relative concentrations of the various ions in the solution, but also by their equivalent conductivities.

Stellwagen, Earle; Stellwagen, Nancy C.

2003-01-01

189

Development of a New Concept in Membrane Structure for Application in Hemodialysis.  

National Technical Information Service (NTIS)

The objective of this program was to develop ultrathin membranes that would exhibit superior transport properties when compared to conventional cellulose membranes. A new, high permeability ultrathin cellulose membrane derived from cellulose acetate has b...

L. T. Rozelle R. J. Petersen

1974-01-01

190

Automated serum protein electrophoresis by Capillarys.  

PubMed

Capillary zone electrophoresis (CZE) of serum proteins is increasingly gaining impact in clinical laboratories. In this report, we evaluate automated capillary zone electrophoresis by Capillarys (Sebia, France). Within-run and between-run imprecision for the five electrophoretic fractions was <2% and <6%, respectively. Data obtained with Capillarys correlated with results obtained with agarose gel electrophoresis and Paragon CZE 2000 (Beckman Coulter, USA). Analysis of serum obtained from patients with inflammation, nephrotic syndrome, bisalbuminemia, and alpha1-antitrypsin deficiency revealed that Capillarys was able to detect these abnormalities. Two hundred thirty eight samples were analyzed by agarose gel electrophoresis, Capillarys, capillary electrophoresis using Paragon CZE 2000 system, and immunofixation. Sample selection was based on the presence of a disturbed morphology (e.g., spike) of the protein profile or hypogammaglobulinemia on agarose gel electrophoresis and/or Capillarys. Immunofixation revealed the presence of a monoclonal protein, oligoclonal bands, polyclonal pattern, and a normal profile in, respectively, 89, 66, 19, and 64 samples. With Capillarys, Paragon, and agarose gel electrophoresis, a spike and/or disturbed morphology of the profile was found in 222, 182, and 180 samples, respectively. In these samples, immunofixation was negative in 73 (33%), 46 (25%), and 39 (22%) samples, respectively. These data indicate that Capillarys has a lower specificity than agarose gel electrophoresis and Paragon 2000. Of the 89 samples with a monoclonal protein, Capillarys, Paragon, and agarose gel electrophoresis failed to detect, respectively, three, three, and one monoclonal protein(s). Interferences by radio-opaque agents, complement degradation products, fibrinogen, and triglycerides are described. In conclusion, automated capillary zone electrophoresis with Capillarys provides for reproducible, rapid, and reliable serum electrophoresis. PMID:12812271

Bossuyt, Xavier; Lissoir, Bénédicte; Mariën, Godelieve; Maisin, Diane; Vunckx, Jozef; Blanckaert, Norbert; Wallemacq, Pierre

2003-05-01

191

Stabilized Calcium Acetate Oil Dispersions.  

National Technical Information Service (NTIS)

A lubricating composition is imparted with improved load-carrying ability and anti-wear properties by incorporation of calcium acetate. The composition consists of a base lubricant, 0.1 to 50 percent by weight calcium acetate and 0.01 to 20 percent by wei...

R. H. Davis

1965-01-01

192

Lead Acetate, Radiotracer Metabolism Study.  

National Technical Information Service (NTIS)

Metabolic studies utilizing radiotracer techniques were applied to tissues from rats which had received 0 and 1000 ppm lead acetate (calculated as lead) for one month prior to the oral administration of 210 lead acetate. Seventy-two hours after administra...

D. C. Jessup

1967-01-01

193

Polymeric membranes for lipase immobilization  

Microsoft Academic Search

Lipase triacylglycerol acylhydrolase, (E.C. 3.1.1.3) is an enzyme that is fully active on aggregated substrates and practically\\u000a inactive on monodisperse systems. A lipase immobilized on polymeric membranes has been applied for sunflower oil hydrolysis.\\u000a The influence of membrane properties on enzyme activity is studied. Membranes made of poly(vinyl chloride), collagen, cellulose\\u000a acetate and polytetrafluoroethylene were used for adsorption of lipase.

Magdalena Rucka; Bo?ena Turkiewicz; Janusz S. ?uk

1990-01-01

194

Quantitation of Plasma Membrane Calcium Pump Phosphorylated Intermediates by Electrophoresis  

Microsoft Academic Search

P-ATPases are characterized by the formation of acid-stable phosphorylated intermediates (EP) during their reaction cycle. We have developed a microscale method to determine EP that involves the phosphorylation of the enzyme using [?-32P]ATP and precipitation with TCA; separation of the sample by SDS-PAGE, and measurement of the enzyme protein and 32P-labeled EP by digital analysis of both the stained gel

Mar??a Mercedes Echarte; Valeria Levi; Ana Mar??a Villamil; Rolando C. Rossi; Juan Pablo F. C. Rossi

2001-01-01

195

Getting the Most out of Electrophoresis Units  

ERIC Educational Resources Information Center

|At Oklahoma City Community College, they have developed gel electrophoresis activities that support active learning of many scientific concepts, including: pH, electrolysis, oxidation reduction, electrical currents, potentials, conductivity, molarity, gel electrophoresis, DNA and protein separation, and DNA fingerprinting. This article presents…

Mulvihill, Charlotte

2007-01-01

196

Speciation of Metal Ions by Capillary Electrophoresis  

Microsoft Academic Search

The speciation of metal ions by capillary electrophoresis is an important area for environmental chemists. The speciation of metal ions by capillary electrophoresis in different matrices is reviewed. Various aspects of speciation such as sample pretreatment, metal ion complexation, detection, detection limit, choice of electrolytes, etc. have been described. Suggestions to improve the application of CE for the speciation of

Imran Ali; Hassan Y. Aboul-Enein

2002-01-01

197

Boswellic acid acetate induces apoptosis through caspase-mediated pathways in myeloid leukemia cells.  

PubMed

The mechanism of the cytotoxic effect of boswellic acid acetate, a 1:1 mixture of alpha-boswellic acid acetate and beta-boswellic acid acetate, isolated from Boswellia carterri Birdw on myeloid leukemia cells was investigated in six human myeloid leukemia cell lines (NB4, SKNO-1, K562, U937, ML-1, and HL-60 cells). Morphologic and DNA fragmentation assays indicated that the cytotoxic effect of boswellic acid acetate was mediated by induction of apoptosis. More than 50% of the cells underwent apoptosis after treatment with 20 mug/mL boswellic acid for 24 hours. This apoptotic process was p53 independent. The levels of apoptosis-related proteins Bcl-2, Bax, and Bcl-XL were not modulated by boswellic acid acetate. Boswellic acid acetate induced Bid cleavage and decreased mitochondrial membrane potential without production of hydrogen peroxide. A general caspase inhibitor (Z-VAD-FMK) and a specific caspase-8 inhibitor II (Z-IETD-FMK) blocked boswellic acid acetate-induced apoptosis. The mRNAs of death receptors 4 and 5 (DR4 and DR5) were induced in leukemia cells undergoing apoptosis after boswellic acid acetate treatment. These data taken together suggest that boswellic acid acetate induces myeloid leukemia cell apoptosis through activation of caspase-8 by induced expression of DR4 and DR5, and that the activated caspase-8 either directly activates caspase-3 by cleavage or indirectly by cleaving Bid, which in turn decreases mitochondria membrane potential. PMID:15767547

Xia, Lijuan; Chen, Duo; Han, Rui; Fang, Qicheng; Waxman, Samuel; Jing, Yongkui

2005-03-01

198

21 CFR 184.1185 - Calcium acetate.  

Code of Federal Regulations, 2013 CFR

...also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets the specifications of the Food Chemicals...

2013-04-01

199

Simultaneous determination of first-line anti-tuberculosis drugs by capillary zone electrophoresis using direct UV detection.  

PubMed

An alternative methodology for simultaneous analysis of ethambutol, isoniazid, rifampicin and pyrazinamide in pharmaceutical formulations by capillary zone electrophoresis under UV direct detection with an analysis time of 8.0 min is proposed. Background running was based on the effective mobility curve of the analytes and an optimum separation condition was achieved using a 3(3) Box-Behnken design, with Brij 35, Cu(2+) and acetic acid/sodium acetate buffer as factors. An electrolyte consisting of 50.0 mmol L(-1) of acetic acid/sodium acetate buffer, 12.5 mmol L(-1) of CuSO(4), and standard and sample solutions prepared in 2.00 mmol L(-1) of Brij 35 and 12.5 mmol L(-1) of CuSO(4) were optimized. After evaluating validation parameters, the method was successfully applied to the analysis of samples in the form of tablets and sachets. PMID:20685475

Faria, Adriana F; de Souza, Marcus V N; Bruns, Roy E; de Oliveira, Marcone A L

2010-04-24

200

21 CFR 862.2485 - Electrophoresis apparatus for clinical use.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Electrophoresis apparatus for clinical...Instruments § 862.2485 Electrophoresis apparatus for clinical...Identification. An electrophoresis apparatus for clinical...including plasma proteins, lipoproteins, enzymes, and...

2010-04-01

201

21 CFR 862.2485 - Electrophoresis apparatus for clinical use.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Electrophoresis apparatus for clinical...Instruments § 862.2485 Electrophoresis apparatus for clinical...Identification. An electrophoresis apparatus for clinical...including plasma proteins, lipoproteins, enzymes, and...

2009-04-01

202

21 CFR 862.2485 - Electrophoresis apparatus for clinical use.  

Code of Federal Regulations, 2013 CFR

...Electrophoresis apparatus for clinical use. 862.2485 Section 862...Electrophoresis apparatus for clinical use. (a) Identification. ...electrophoresis apparatus for clinical use is a device intended to separate...plasma proteins, lipoproteins, enzymes, and hemoglobulins on...

2013-04-01

203

Draft Guidance on Norethindrone Acetate Active ingredient ...  

Center for Drug Evaluation (CDER)

Text VersionPage 1. Contains Nonbinding Recommendations Draft Guidance on Norethindrone Acetate ... Active ingredient: Norethindrone Acetate ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

204

Nonlinear waves in capillary electrophoresis  

PubMed Central

Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity. If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers’ equation is recovered, and thus, the time dependent problem is exactly solvable with arbitrary initial conditions. In the case of small diffusivity either a leading edge or trailing edge shock is formed depending on the electrophoretic mobility of the sample ion relative to the background ions. Analytical formulas are presented for the shape, width and migration velocity of the sample peak and it is shown that axial dispersion at long times may be characterized by an effective diffusivity that is exactly calculated. These results are consistent with known observations from physical and numerical simulation experiments.

Ghosal, Sandip; Chen, Zhen

2011-01-01

205

Phenomenology of colloidal crystal electrophoresis  

NASA Astrophysics Data System (ADS)

We studied the motion of polycrystalline solids comprising of charged sub-micron latex spheres suspended in deionized water. These were subjected to a low frequency alternating square wave electric field in an optical cell of rectangular cross section. Velocity profiles in X and Y direction were determined by Laser Doppler Velocimetry. The observed complex flow profiles are time dependent due to the combined effects of electro-osmosis, electrophoresis, crystal elasticity, and friction of the crystals at the cell wall. On small time scales elastic deformation occurs. On long time scales channel formation is observed. At intermediate times steady state profiles are dominated by a solid plug of polycrystalline material moving in the cell center. At large field strengths the plug shear melts. Mobilities in the shear molten state are on the order of (6.5+/-0.5) 10-8 m2 V-1 s-1 and connect continuously with those of the equilibrium fluid. The apparent mobility of the plug is much larger than of the fluid and like the mobility of the fluid decreases with increasing particle number density. We qualitatively attribute the accelerated motion of the plug to an incomplete exposure to the electro-osmotic flow profile.

Medebach, Martin; Palberg, Thomas

2003-08-01

206

Methanogenesis from acetate: enrichment studies.  

PubMed Central

An acetate enrichment culture was initiated by inoculating anaerobic sludge from a mesophilic methane digestor into a mineral salts medium with calcium acetate as the sole carbon and energy source. This enrichment was maintained indefinitely by weekly transfer into medium of the same composition. A study of this enrichment disclosed an unexpected age-dependent inhibition of methanogenesis by H2 and formate which apparently differed from the inhibition by chloroform and benzyl viologen. This age-dependent inhibition indicated that microbial interactions of the mixed enrichment population may play a regulatory role in methane formation. Futhermore, stimulation of methanogenesis in the acetate enrichment by addition of yeast extract showed a nutrient limitation which indicated that syntrophic interactions leading to formation of growth factors may also occur. A model is presented to illustrate the possible interrelationships between methanogenic and nonmethanogenic bacteria in their growth and formation of methane and carbon dioxide from acetate. Images

Baresi, L; Mah, R A; Ward, D M; Kaplan, I R

1978-01-01

207

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

208

Molecular Structure of Acetic acid  

NSDL National Science Digital Library

Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

2003-06-02

209

Acetate catabolism by Methanosarcina barkeri  

SciTech Connect

Cell suspensions of Methanosarcina barkeri convert the carboxyl and methyl group carbons of acetate to carbon dioxide and methane at pH 6 under an atmosphere of 100% CO/sub 2/. The rate of loss of radioactivity from (1-/sup 14/C)acetate was over three times greater than that from (2-/sup 14/C)acetate under these conditions. Control experiments with both labeled substrates present showed that the rates were additive. Addition of a high level of 2-bromoethanesulfonate to selectively inhibit methane formation largely inhibited release of /sup 14/C from methyl-labeled acetate but only marginally decreased the rate of loss from (1-/sup 14/C)acetate. Thus, in the absence of the inhibitor loss of /sup 14/C from (1-/sup 14/C)acetate likely reflects an isotopic exchange reaction with CO/sub 2/ superimposed on the overall conversion of acetate to CO/sub 2/ and CH/sub 4/. The exchange reaction was inhibited by uncouplers such as 2,4-dinitrophenol, CCCP, and FCCP. Cells permeabilized by treatment with nonionic detergents or disrupted by passage through a French pressure cell failed to catalyze the exchange reaction. Exchange activity was not restored by addition of ATP or by use of (1-/sup 14/C)acetyl CoA as substrate. No evidence for involvement of carbon monoxide dehydrogenase in the exchange was found in these experiments when CO/sub 2/ was replaced by CO. However, the soluble extracts retained the ability to convert acetate to methane in the presence of H/sub 2/ and ATP.

Grahame, D.A.

1987-05-01

210

MEMBRANE SURFACE MODIFICATION AND BACKPULSING FOR WASTEWATER TREATMENT  

Microsoft Academic Search

Using a novel photoinduced grafting method, hydrophobic polypropylene (PP) membranes were rendered hydrophilic by grafting monomers of poly(ethylene glycol 200) monomethacrylate (PEG200MA), dimethyl aminoethyl methacrylate (DMAEMA), or acrylic acid (AA), to produce a neutral, positive, or negative charge, respectively, on the membrane surface. Using both unmodified and modified PP membranes, as well as a hydrophilic cellulose acetate (CA) membrane, the

Huimin Ma; David R. Nielsen; Christopher N. Bowman; Robert H. Davis

2001-01-01

211

Improved Isolation Procedures for the Purple Membrane of Halobacterium Halobium  

Microsoft Academic Search

Techniques for purifying the purple membrane of Halobacterium halobium are given. This purple membrane contains a chromoprotein with a retinal prosthetic group similar to rhodopsin, the chromoprotein found in the visual systems of higher invertebrates and vertebrates. The described purple membrane isolation procedures yield a highly purified preparation as determined by transmitting electron microscopy and gel electrophoresis. Critical analysis of

Brian M. Becher; Seph Y. Cassim

1975-01-01

212

High-performance capillary electrophoresis of histones  

SciTech Connect

A high performance capillary electrophoresis (HPCE) system has been developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in a 0.1M phosphate buffer at pH 2.5 in a 50 {mu}m {times} 35 cm coated capillary. Electrophoresis was accomplished in 9 minutes separating a whole histone preparation into its components in the following order of decreasing mobility; (MHP) H3, H1 (major variant), H1 (minor variant), (LHP) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B, (MHP) H2A (minor variant) where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase HPLC and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. 27 refs., 8 figs.

Gurley, L.R.; London, J.E.; Valdez, J.G.

1991-01-01

213

Rotor for Centrifugal Testing of Electrophoresis Gel.  

National Technical Information Service (NTIS)

The patent application describes a rotor for the preparation of identical electrophoresis gels where the liquid is permitted to flow into a rotor bowl under dynamic conditions. The rotor comprises a cylindrical body, a sealable closure, a central core, an...

1974-01-01

214

Microgel electrophoresis: sensitivity, mechanisms, and DNA electrostretching.  

PubMed

Based on the treatment of microgels to remove proteins, we speculate that proteins may be bound to DNA in the microgels even after electrophoresis. We speculate that some DNA single-strand breaks may be a reflection of these protein-DNA complexes. We suggest methods to limit such artifacts, and present data demonstrating a lymphocyte DNA double-strand break sensitivity of 12.5 rads and day-to-day reproducibility of microgel electrophoresis using these principles. Extending these principles, we describe DNA behavior during alkaline and neutral microgel electrophoresis based on observations of the stained DNA and its migration patterns. During microgel electrophoresis, individual DNA molecules behave as if anchored at one end while the other end is free to migrate in response to the electric field. We capitalize on this behavior by developing a neutral microgel method to stretch chromosomes. PMID:9088349

Singh, N P; Stephens, R E

1997-03-12

215

Electrophoresis in Polyvinyl-Alcohol Gel.  

National Technical Information Service (NTIS)

It was found that electrophoresis in polyvinyl-alcohol, although not completely equivalent to that in polyacrylamide, is entirely possible and can accordingly be employed as an alternative method in certain cases, e.g. difficulties of procurement of polya...

C. Reich H. Sieber

1967-01-01

216

Acute synovitis and intra-articular methylprednisolone acetate in ponies  

Microsoft Academic Search

Objective: To determine how acute synovitis, with and without intra-articular methylprednisolone acetate (MPA), affect synthesis of proteoglycan, total protein, and collagen in articular cartilage and total protein synthesis in synovial membrane.Design: Synovitis was induced in 10 ponies by the injection of 0.5 ng lipopolysaccharide (LPS) into the left radiocarpal and midcarpal joints every 2 days for a total of four

Rory J. Todhunter; Susan L. Fubini; Margaret Vernier-Singer; Joyce A. M. Wootton; George Lust; Kathleen P. Freeman; James N. MacLeod

1998-01-01

217

Two-dimensional electrophoretic analysis of secretory-granule, granule-membrane, and plasma-membrane proteins of rat parotid cells  

Microsoft Academic Search

Secretory granules and plasma membranes were isolated from rat parotid cells and characterized enzymatically and by electron microscopy. The proteins of the secretory granule membranes, the secretory granules and the plasma membranes were characterized by two-dimensional polyacrylamide gel electrophoresis and visualized by silver staining. The granule membrane contains 166 polypeptides of which only 26 are also present in the granule

Margaret A. Cascieri; Ethel W. Somberg

1983-01-01

218

Analysis of Simple Carbohydrates by Capillary Electrophoresis and Capillary Electrophoresis–Mass Spectrometry  

Microsoft Academic Search

\\u000a An overview of the application of capillary electrophoresis and ­capillary electrophoresis–mass spectrometry in the analysis\\u000a of simple carbohydrates without any previous derivatization step is given. Besides electrolyte systems for ­carbohydrate separation,\\u000a detection techniques employed in capillary electrophoresis, such as ­spectrophotometric detection, electrochemical detection,\\u000a and mass spectrometric ­detection, are discussed, as are less common detection techniques. Thus, the chapter focuses on

Christian W. Klampfl; Markus Himmelsbach; Wolfgang Buchberger

219

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+methyl ethyl ketone (MEK), MEK+isopropyl acetate, acetic acid+MEK+water and acetic acid+MEK+isopropyl acetate+water are measured at 101.33kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in

Qiang Xie; Hui Wan; MingJuan Han; GuoFeng Guan

2009-01-01

220

Effect of the Buffer Concentration on the Separation of Lactate Dehydrogenase Isoenzymes from Different Sources by Electrophoresis  

Microsoft Academic Search

The separation of lactate dehydrogenase isoenzymes by zone electrophoresis using cellulose acetate strips as support was dependent on the concentration of the buffer used (5 mM and 50 mM, pH 7.4) and on the source of the material (chicken liver or guinea-pig liver).In three different 5 mM buffer systems, pH 7.4 (phosphate, veronal and Tris-HC1) the four lactate dehydrogenase isoenzymes

S. Imperial; J. Li Gelpí; M. Busquets; A. Mazo; A. Cortés

1991-01-01

221

New process for producing cellulose acetate from wood in concentrated acetic acid  

Microsoft Academic Search

To explore further potential applications of acetic acid pulp, an investigation was conducted to develop a direct method for producing cellulose acetate from wood in combination with atmospheric acetic acid pulping. The process consists of delignification, totally chlorine-free bleaching, and esterification, with the concentrated acetic acid aqueous solution being used as only solvent throughout the process. The acetic acid pulp

Hironori Sato; Yasumitsu Uraki; Takao Kishimoto; Yoshihiro Sano

2003-01-01

222

REMOVAL OF ACETIC ACID IMPURITIES FROM ETHYL ACETATE BY ADSORPTION ON ION EXCHANGE RESINS  

Microsoft Academic Search

Removal of acetic acid impurities from ethyl acetate was attempted by sorption on basic ion-exchange resins. Kinetic studies showed that acid removal is controlled by intraparticle resistance from both ethyl acetate and alcohol. Breakthrough curves for uptake of the acid from ethyl acetate were obtained at different flow rates and concentrations. Desorption studies were performed using both ethyl acetate and

H. M. Anasthas; V. G. Gaikar

2001-01-01

223

Acetate and Formate Stress: Opposite Responses in the Proteome of Escherichia coli  

PubMed Central

Acetate and formate are major fermentation products of Escherichia coli. Below pH 7, the balance shifts to lactate; an oversupply of acetate or formate retards growth. E. coli W3110 was grown with aeration in potassium-modified Luria broth buffered at pH 6.7 in the presence or absence of added acetate or formate, and the protein profiles were compared by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Acetate increased the steady-state expression levels of 37 proteins, including periplasmic transporters for amino acids and peptides (ArtI, FliY, OppA, and ProX), metabolic enzymes (YfiD and GatY), the RpoS growth phase regulon, and the autoinducer synthesis protein LuxS. Acetate repressed 17 proteins, among them phosphotransferase (Pta). An ackA-pta deletion, which nearly eliminates interconversion between acetate and acetyl-coenzyme A (acetyl-CoA), led to elevated basal levels of 16 of the acetate-inducible proteins, including the RpoS regulon. Consistent with RpoS activation, the ackA-pta strain also showed constitutive extreme-acid resistance. Formate, however, repressed 10 of the acetate-inducible proteins, including the RpoS regulon. Ten of the proteins with elevated basal levels in the ackA-pta strain were repressed by growth of the mutant with formate; thus, the formate response took precedence over the loss of the ackA-pta pathway. The similar effects of exogenous acetate and the ackA-pta deletion, and the opposite effect of formate, could have several causes; one possibility is that the excess buildup of acetyl-CoA upregulates stress proteins but excess formate depletes acetyl-CoA and downregulates these proteins.

Kirkpatrick, Christopher; Maurer, Lisa M.; Oyelakin, Nikki E.; Yoncheva, Yuliya N.; Maurer, Russell; Slonczewski, Joan L.

2001-01-01

224

Validated capillary electrophoresis method for small-anions measurement in wines.  

PubMed

A capillary electrophoresis method has been developed and validated for acetic, citric, fumaric, lactic, malic, oxalic, succinic, and tartaric acids plus the measurement of nitrate and sulfite ions in white and red wines. The separation was carried out in a neutral coated capillary. Separation was performed at -14 kV of applied potential. Temperature was maintained at 20 degrees C. The background electrolyte used was 200 mM phosphate buffer at pH 7.50. Separation was obtained in less than 13 min. Validation parameters obtained for the method permit it to be considered adequate for routine analysis. PMID:12858396

Saavedra, Luis; Barbas, Coral

2003-06-01

225

Vibrational spectroscopy and electrophoresis as a "golden means" in monitoring of polysaccharides in medical plant and gels  

NASA Astrophysics Data System (ADS)

In recent years, some bioactive polysaccharides isolated from natural sources have attracted much attention in the field of biochemistry and pharmacology. Of them, polysaccharides or their glycoconjugates were shown to exhibit multiple biological activities including anticarcinogenic, anticoagulant, immunostimulating, antioxidant, etc. Pharmacotherapy using plant-derived substances can be currently regarded as a very promising future alternative to conventional therapy. The advanced biotechnologies available today enable chemical investigation of well-defined bioactive plant components as sources of novel drugs. The need for safer drugs without side effects has led to the use of natural ingredients with proven safety. Special interest is focused on plant polysaccharides. This article attempts to review the current structural and conformational characterization of some importantly bioactive monosaccharides isolated from following plant cell-wall: Symphytum officinale (comfrey), Thymus pulegioides (thyme), Trigonella foenum-graecum L. (fenugreek), Tussilago farfara L. (coltsfoot), Hyssopus officinalis (hyssop), Althaea officinalis L. (marshmallow) and Equisetum arvense L. (horsetail). The chemical structures of monosaccharides were analysed using FTIR and Raman spectroscopies as well as cellulose acetate membrane electrophoresis (CAE). The dried plant samples were gently hydrolysed with sulphuric acid. The presence of glucuronic acid, galacturonic acid, alginic acid, glucose, mannose and xylose in the hydrolysates of reference substances and non-defatted plant films was proved. The possibility of a taxonomic classification of plant cell walls based on infrared and Raman spectroscopies and the use of spectral fingerprinting for authentication and detection of adulteration of products rich in cell-wall materials are discussed. Individual bands were selected to monitor the sugar content in medical plant cell walls and to confirm the identity of the analysed plants.

Pielesz, A.

226

Characterization of the microdialysis junction interface for capillary electrophoresis\\/microelectrospray ionization mass spectrometry  

Microsoft Academic Search

A capillary electrophoresis\\/electrospray ionization mass spectrometry (CE\\/ESI-MS) interface, based on an electric circuit across a microdialysis membrane surrounding a short capillary segment closely connected to the separation capillary terminus, is demonstrated to be sensitive, efficient, and rugged. A microspray type ionization emitter produces a stable electrospray at the low flow rates provided by CE and thus avoids both the need

Joanne C. Severs; Richard D. Smith

1997-01-01

227

An immunoblotting technique for direct visualization of Chido and Rodgers reactivity on C4 variants after electrophoresis.  

PubMed

An immunoblotting technique allows direct visualization of Chido and Rodgers antigenic determinants on intact C4 proteins. C4 molecules separated by electrophoresis are selectively transferred to nitrocellulose membranes saturated with goat antiserum to human C4. The membranes are then incubated in alloanti-Chido or anti-Rodgers followed by enzyme-conjugated goat antihuman IgG. Molecules with Chido or Rodgers reactivity are visualized by incubation with an indicator substrate for the bound enzyme. PMID:2450426

Sklarin, P M; Awdeh, Z L; Alper, C A

1988-01-01

228

Membrane fouling during microfiltration of protein mixtures  

Microsoft Academic Search

Crossflow microfiltration is an efficient method for the clarification, stabilization and sterilization of fruit juices and other biological suspensions. One of the main problems with the application of this technique, however, is membrane fouling caused by the presence of proteins and polysaccharides. The fouling behavior of four 0.2 ?m hydrophilic microfiltration membranes (polysulfone, polycarbonate, polyvinylidene fluoride, and cellulose acetate) is

Carme Güell; Robert H. Davis

1996-01-01

229

Monocarboxylic acid permeation through lipid bilayer membranes  

Microsoft Academic Search

Summary The membrane permeability coefficients for the homologous monocarboxylic acids, formic through hexanoic, as well as benzoic and salicylic, were determined for egg phosphatidylcholine-decane planar bilayer membranes. The permeabilities of formic, acetic and propionic acid were also determined for “solvent-free” phosphatidylethanolamine bilayers. Permeability coefficients were calculated from tracer fluxes measured under otherwise symmetrical conditions, and precautions were taken to ensure

Anne Walter; John Gutknecht

1984-01-01

230

Minute electric field reduced membrane fouling and improved performance of membrane bioreactor  

Microsoft Academic Search

Effective application of a low voltage and low intensity electric field in EMBR (a membrane bioreactor attached with electric field) may reduce fouling, energy consumption, while enhance treatment efficiency. For that, electrodes and membrane modules were re-arranged in EMBR to maintain constant electrophoresis forces against deposition\\/adsorption of extra-cellular polymeric substances (EPS) or sludge particles on the membrane. The copper wire

Lifen Liu; Jiadong Liu; Bo Gao; Fenglin Yang

231

Metalloporphyrin-based acetate-selective electrodes as detectors for enzymatic acetylcholine determination in flow-injection analysis system  

Microsoft Academic Search

In this work two Zr(IV)-porphyrins were tested as potential acetate-selective ionophores. It is shown that these compounds show increased selectivity towards acetate ion, with selectivity sequence: Cl?acetate?membranes. Among tested ionophores, Zr(IV)-tetra(tert-butylphenyl)porphyrin was found to be the best in terms of response time (20s) and lower detection limit (2×10?4M acetate?).Designed electrodes were used as detectors

?ukasz Górski; Monika Mroczkiewicz; Mariusz Pietrzak; El?bieta Malinowska

2009-01-01

232

A new injection method for soil nutrient analysis in capillary electrophoresis  

NASA Astrophysics Data System (ADS)

We present a new method for the direct injection of liquid sample into a capillary electrophoresis (CE) device. Instead of a double-T injection mechanism, a single inlet provided with a membrane filter is used. From a reservoir on top of this inlet, the liquid directly enters the separation channel through the membrane. The driving force is a short electrical pulse. This avoids an additional sample channel, so that the chip needs only three microfluidic connects and no mechanical sample pumping is demanded. The high injection reproducibility and the comparatively simple setup open up the way for mobile application of soil analysis.

Smolka, M.; Puchberger-Enengl, D.; Bipoun, M.; Fercher, G.; Klasa, A.; Krutzler, C.; Keplinger, F.; Vellekoop, M. J.

2013-05-01

233

Azithromycin as a new chiral selector in capillary electrophoresis.  

PubMed

In capillary electrophoresis (CE), separation of enantiomers of a chiral compound can be achieved through the chiral interactions and/or complex formation between the chiral selector and the enantiomeric analytes on leaving their diastereomeric forms with different stability constants and hence different mobilities. A great number of chiral selectors have been employed in CE and among them macrocyclic antibiotics exhibited excellent enantioselective properties towards a wide number of racemic compounds. The use of azithromycin (AZM) as a chiral selector has not been reported previously. This work reports the use of AZM as a chiral selector for the enantiomeric separations of five chiral drugs and one amino acid (tryptophan) in CE. The enantioseparation is carried out using polar organic mixtures of acetonitrile (ACN), methanol (MeOH), acetic acid and triethylamine as run buffer. The influences of the chiral selector concentration, ACN/MeOH ratio, applied voltage and capillary temperature on enantioseparation are investigated. The results show that AZM is a viable chiral selector in CE for the enantioseparation of the type of chiral drugs investigated. PMID:21256503

Kumar, Avvaru Praveen; Park, Jung Hag

2011-01-01

234

Separation of carbon nanotubes in aqueous medium by capillary electrophoresis.  

PubMed

A robust and reproducible method for the dispersion of carbon nanotubes, either single-walled or multi-walled is presented. Dispersion of nanotubes was achieved as surfactant-coated species of sodium dodecyl sulphate. The addition of small amounts of hydroxypropyl methyl cellulose (HPMC) together with the surfactant, sodium dodecyl sulphate, was found critical to achieve reproducible nanotubes dispersion and to obtain an homogeneous and stable solution. This solution is further analyzed by capillary electrophoresis using a background electrolyte solution containing a polymer, 0.025% (w/v) HPMC solution prepared in 5 mM ammonium acetate at pH 8.03. This electrophoretic method presents a high reproducibility between runs, being an interesting alternative to study nanotube size distribution or characterization after synthesis. In addition, the methodology developed allowed the study of the interaction of the different types of carbon nanotubes with a molecular probe such as pentachlorophenol. This procedure was showed effective to detect small differences on the chemical/physical surface properties of the nanotubes. The different interaction behavior found within the two SWNTs selected was critically discussed. PMID:16842803

Suárez, Beatriz; Simonet, Bartolomé M; Cárdenas, Soledad; Valcárcel, Miguel

2006-07-13

235

Fragrance material review on 2,4-dimethylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of 2,4-dimethylbenzyl acetate when used as a fragrance ingredient is presented. 2,4-Dimethylbenzyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, iso-butyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2,4-dimethylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414641

McGinty, D; Letizia, C S; Api, A M

2012-03-05

236

Fragrance material review on p-anisyl acetate.  

PubMed

A toxicologic and dermatologic review of p-anisyl acetate when used as a fragrance ingredient is presented. p-Anisyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for p-anisyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, and genotoxicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22417777

McGinty, D; Letizia, C S; Api, A M

2012-03-06

237

Alcohol dehydrogenase of acetic acid bacteria: structure, mode of action, and applications in biotechnology  

Microsoft Academic Search

Pyrroquinoline quinone-dependent alcohol dehydrogenase (PQQ-ADH) of acetic acid bacteria is a membrane-bound enzyme involved\\u000a in the acetic acid fermentation by oxidizing ethanol to acetaldehyde coupling with reduction of membranous ubiquinone (Q),\\u000a which is, in turn, re-oxidized by ubiquinol oxidase, reducing oxygen to water. PQQ-ADHs seem to have co-evolved with the organisms\\u000a fitting to their own habitats. The enzyme consists of

Toshiharu Yakushi; Kazunobu Matsushita

2010-01-01

238

Immunochemical studies of infectious mononucleosis. V. Isolation and characterization of a glycoprotein from goat erythrocyte membranes.  

PubMed

A glycoprotein was isolated from goat erythrocyte membranes by extraction with hot 75% ethanol. The glycoprotein was purified by ethanol precipitation, phosphocellulose chromatography gel filtration, ethyl:ether and chloroform:methanol extraction. In aqueous phosphate-buffered saline, pH 7, the glycoprotein was in an aggregated state with a sedimentation coefficient (S(obs)) to 1.5. Electrophoresis of the glycoprotein on polyacrylamide gels containing phosphate-buffered 0.1% SDS gave a single band, staining with both periodic acid Schiff (PAS) and Coomassie Blue (CB). The apparent m.w., calculated from retardation coefficient, was 25,000. Electrophoresis of the glycoprotein on 1% SDS gels buffered with Tris-acetate (pH 7.4) showed a major band of similar (23,500) apparent m.w. plus four other PAS- and CB-staining bands of lower mobility. With 131I-labeled glycoprotein, recovery of bands from gels, sialic acid analysis, heterophile antigen activity, and re-electrophoresis, it was shown that these additional bands were aggregated forms of a single or closely related glycoprotein species. The purified glycoprotein contained 50% carbohydrate with molar ratios of sialic acid:galactose:mannose:galactosamine:glucosamine of 3.1:2.1:0.1:1.6:1. The glycoprotein was highly reactive with the Paul-Bunnell heterophile antibody in the sera of patients with infectious mononucleosis, with Limulus polyphemus lectin and weakly ractive with wheat germ agglutinin. These reactivities were destroyed by neuraminidase treatment or by alkaline sodium borohydride. The native glycoprotein did not react with lectins from Canavalia enisformis, Phaseolus vulgaris, Ricinus communis, or Vicia graminea although it was reactive with the latter two after neuraminidase treatment. PMID:956650

Fletcher, M A; Lo, T M; Graves, W R

1976-09-01

239

Isolation and Partial Characterization of the Major Amide-Linked Conjugate of Indole-3-Acetic Acid from Phaseolus vulgaris L. 1  

PubMed Central

A major indole-3-acetic acid conjugate from Phaseolus vulgaris seed has been isolated and partially characterized. It is a 3 kilodalton peptide with apparently 2 indole-3-acetyl moieties in amide linkage per peptide. The indole-3-acetic acid component was identified by gas chromatography-mass spectrometry and the peptide characterized by polyacrylamide gel electrophoresis, by amino acid analysis using dabsyl derivatives and by its Fourier transform-infrared spectrum. This is the first higher molecular weight amide-linked indole-3-acetic acid conjugate to be characterized from higher plants. Images Fig. 4

Bialek, Krystyna; Cohen, Jerry D.

1986-01-01

240

Biofiltration of ethyl acetate and amyl acetate using a composite bead biofilter.  

PubMed

Biodegradation kinetic behaviors of ethyl acetate and amyl acetate in a composite bead biofilter were investigated. The composite bead was the spherical PVA/peat/KNO3/GAC composite bead which was prepared in our previous works. Both microbial growth rate and biochemical reaction rate were inhibited at higher inlet concentration. For the microbial growth process, the microbial growth rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The degree of inhibitive effect was almost the same for ethyl acetate and amyl acetate in this concentration range. The half-saturation constant Ks values of ethyl acetate and amyl acetate were 16.26 and 12.65ppm, respectively. The maximum reaction rate Vm values of ethyl acetate and amyl acetate were 4.08 and 3.53gCh(-1)kg(-1) packed material, respectively. Zero-order kinetic with the diffusion limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The inhibitive effect for ethyl acetate was more pronounced than that for AA in this concentration range. The maximum elimination capacity of ethyl acetate and amyl acetate were 82.3 and 37.93gCh(-1)m(-3) bed volume, respectively. Ethyl acetate degraded by microbial was easier than amyl acetate did. PMID:18445522

Chan, Wu-Chung; Su, Mei-Qi

2008-04-28

241

MINIRIN Desmopressin acetate 1. EXECUTIVE SUMMARY ..... ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Brand Name MINIRIN Generic Name Desmopressin acetate ... NDA 21795 MINIRIN (desmopressin acetate) 0.1 mg and 0.2 mg Tablets Page 1 of 30 ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

242

Mechanism and Molecular Interactions in the Transport of Water through Membranes.  

National Technical Information Service (NTIS)

Changes in waveguide properties of several cellulose acetate membranes and one polyimide membrane were measured as a function of their exposure to varying levels of relative humidity. The volume fraction of water in the films and the occupied pore volumes...

J. R. Scherer G. F. Bailey D. P. Malladi S. Kint

1983-01-01

243

Qualitative yeast enzyme analysis by electrophoresis  

Microsoft Academic Search

Baker's yeast (Saccharomyces cerevisiae) was cultivated under different intensities of aeration on glucose and on ethanol. Seventeen enzymes of the Embden-Meyerhof pathway and the TCA cycle or related reactions were then assayed by starch gel electrophoresis. There were both qualitative and quantitative differences in many enzymes, most notably in glyceraldehyde-3-phosphate dehydrogenase, alcohol dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase, and fumarase. Enzyme

Anssi Saura; Juhani Lokki; Erkki Oura; Heikki Suomalainen

1979-01-01

244

DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.  

SciTech Connect

Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

2004-03-24

245

DNA Electrophoresis Studied with the Cage Model  

Microsoft Academic Search

The cage model for polymer reptation, proposed by Evans and Edwards, and its recent extension to model DNA electrophoresis are studied by numerically exact computation of the drift velocities for polymers with a length L of up to 15 monomers. The computations show the Nernst–Einstein regime (v?E) followed by a regime where the velocity decreases exponentially with the applied electric

A. van Heukelum; G. T. Barkema; R. H. Bisseling

2002-01-01

246

Ratcheted electrophoresis for rapid particle transport.  

PubMed

Ratcheted electrophoresis of contact-charged particles allows for high speed transport through microfluidic channels over large distances and even against fluid flows. Using a set of predictive design heuristics, we demonstrate an extension of this microfluidic ratchet to separate conductive particles from a particle suspension. PMID:24064932

Drews, Aaron M; Lee, Hee-Young; Bishop, Kyle J M

2013-10-15

247

Planetary In Situ Capillary Electrophoresis System (PISCES)  

NASA Astrophysics Data System (ADS)

We propose to develop PISCES, a 3-kg, 2W, flight-capable microfluidic lab-on-a-chip capillary electrophoresis analyzer capable of ingesting solid, liquid, or gas samples and performing a suite of chemical analyses with parts per trillion sensitivity.

Willis, P. A.; Stockton, A. M.; Mora, M. F.; Cable, M. L.; Bramall, N. E.; Jensen, E. C.; Jiao, H.; Lynch, E.; Mathies, R. A.

2012-10-01

248

Microfabricated capillary electrophoresis sensor for uranium (VI)  

Microsoft Academic Search

Arsenazo III, a metallochromic ligand colorimetrically sensitive to the metal complexation of lanthanide and actinide metal ions, is applied to a capillary electrophoresis microchip for the detection of uranium (VI) and various lanthanide metal ions. The glass microchip contained 100?m deep by 200?m wide microchannels etched in a simple cross pattern with an 80mm separation channel length and an 8mm

Greg E. Collins; Qin Lu

2001-01-01

249

Fused quartz substrates for microchip electrophoresis  

Microsoft Academic Search

A fused quartz microchip is fabricated to perform capillary electrophoresis of metal ions complexed with 8-hydroxyquinoline-5-sulfonic acid (HQS). The channel manifold on the quartz substrate is fabricated using standard photolithographic, etching, and deposition techniques. By incorporating a direct bonding technique during the fabrication of the microchip, the substrate and cover plate can be fused together below the melting temperature for

Stephen C. Jacobson; Alvin W. Moore; J. Michael. Ramsey

1995-01-01

250

Clinical Analysis by Microchip Capillary Electrophoresis  

Microsoft Academic Search

Clinical analysis often requires rapid, automated, and high-throughput analytical systems. Microchip capillary electrophoresis (CE) has the potential to achieve very rapid analysis (typically seconds), easy integration of multiple analytical steps, and parallel operation. Al- though it is currently still in an early stage of develop- ment, there are already many reports in the literature describing the applications of microchip CE

Sam F. Y. Li; Larry J. Kricka

251

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2013 CFR

...ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a...additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp...The amount of the lead acetate in the cosmetic shall be such that the lead...

2013-04-01

252

27 CFR 21.107 - Ethyl acetate.  

Code of Federal Regulations, 2013 CFR

...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

2013-04-01

253

Kinetics of the Methanogenic Fermentation of Acetate  

PubMed Central

Inhibition of the fermentation of acetate to methane and carbon dioxide by acetate was analyzed with an acetate-acclimatized sludge and with Methanosarcina barkeri Fusaro under mesophilic conditions. A second-order substrate inhibition model, qch4 = qmS/[Ks + S + (S2/Ki)], where S was the concentration of undissociated acetic acid, not ionized acetic acid, could be applicable in both cases. The analysis resulted in substrate saturation constants, Ks, of 4.0 ?M for the acclimatized sludge and 104 ?M for M. barkeri. The threshold concentrations of undissociated acetic acid when no further acetate utilization was observed were 0.078 ?M (pH 7.50) for the acclimatized sludge and 4.43 ?M (pH 7.45) for M. barkeri. These kinetic results suggested that the concentration of undissociated acetic acid became a key factor governing the actual threshold acetate concentration for acetate utilization and that the acclimatized sludge in which Methanothrix spp. appeared dominant could utilize acetate better and survive at a lower concentration of undissociated acetic acid than could M. barkeri. Images

Fukuzaki, Satoshi; Nishio, Naomichi; Nagai, Shiro

1990-01-01

254

Organic compounds passage through RO membranes  

Microsoft Academic Search

Organic solute permeation, sorption, and rejection by reverse osmosis membranes, from aqueous solutions, were studied experimentally and via artificial neural networks (ANN)-based quantitative structure–property relations (QSPR), for a set of fifty organic compounds for polyamide and cellulose acetate membranes. Membrane solute sorption and passage for dead-end filtration model experiments were quantified based on radioactivity measurements for radiolabeled compounds in the

Dan Libotean; Jaume Giralt; Robert Rallo; Yoram Cohen; Francesc Giralt; Harry F. Ridgway; Grisel Rodriguez; Don Phipps

2008-01-01

255

Membranous nephropathy  

MedlinePLUS

Membranous nephropathy is a kidney disorder that leads to changes and inflammation of the structures inside the kidney ... Membranous nephropathy is caused by the thickening of part of the glomerular basement membrane. The glomerular basement membrane ...

256

Characterization of bore pressure change effects on Matrimid ® fiber performance in pervaporation of acetic acid and water mixtures  

Microsoft Academic Search

A mathematical model was used to account for the bore pressure change effects observed for Matrimid® hollow fiber membranes to obtain the inherent water permeability and membrane selectivity in pervaporation of 20%wt acetic acid (HAc) and water mixtures. The modeled water flux was close to the experimental result for a large bore size fiber (bore size ?350?m) with 20cm length

Fangbin Zhou; William J. Koros

2006-01-01

257

Gel Electrophoresis on a Budget to Dye For  

NSDL National Science Digital Library

Gel electrophoresis is one of the most important tools used in molecular biology and has facilitated the entire field of genetic engineering by enabling the separation of nucleic acids and proteins. However, commercial electrophoresis kits can cost up to

Yu, Julie H.

2010-01-01

258

Lipoprotein Agarose Gel Electrophoresis. Application in HDL-Cholesterol Methodology.  

National Technical Information Service (NTIS)

We perform agarose gel lipoprotein electrophoresis (AGLE) in this laboratory using glass microscope slides to support the agarose gel and 0.025 M barbital buffer for the electrophoresis. This report describes details, including special apparatus used to f...

E. L. Mosser D. A. Clark

1985-01-01

259

Using Gel Electrophoresis To Illustrate Protein Diversity and Isoelectric Point.  

ERIC Educational Resources Information Center

|Demonstrates the differences in protein structures by focusing on isoelectric point with an experiment that is observable under certain pH levels in gel electrophoresis. Explains the electrophoresis procedure and reports results of the experiments. (YDS)|

Browning, Mark; Vanable, Joseph

2002-01-01

260

Model Hydrophobic Ion Exchange Membrane  

PubMed Central

Two models of hydrophobic ion exchange membranes were examined theoretically with regard to the characteristics of cellulose acetate-nitrate membranes saturated with hydrophobic solvents. The first model, consisting of fixed negative sites dispersed in a homogeneous medium of low dielectric constant, was shown to be invalid for the experimental membranes. The second model, consisting of fixed negative sites in an aqueous channel surrounded by a medium of low dielectric constant, explains many properties of the cellulose acetate-nitrate hydrophobic membranes and was analyzed in some detail. Organic cations can enter the membranes through the hydrophobic phase as well as through the aqueous channels. The mechanism of counterion movement in such a model is assumed to consist of exchange of vacancies and or double-occupied sites positions. The presence of the medium of low dielectric constant around the aqueous channel increases the “self”-energy of the ions in the channel and the electrostatic interaction between a fixed site and a counterion in the membrane. Both these factors can account for the marked dependence of ion mobility in the aqueous channels on the dielectric constant of the surrounding medium. The model predicts membrane preference for monovalent counterions over divalent ones. ImagesFigure 3

Shohami, Esther; Ilani, Asher

1973-01-01

261

Protein Electrophoresis in the Biology Classroom Using "Safe" Gels.  

ERIC Educational Resources Information Center

|Describes the use of electrophoresis in the high school utilizing two new gels that are easy to pour, do not require degassing, can be used on a horizontal gel electrophoresis, and are not neurotoxic or carcinogenic health hazards. Large diagrams and written instructions are used to present the protocol of setting up the electrophoresis. (PR)|

Atkins, Thomas

1991-01-01

262

Plasma membrane of Entamoeba histolytica  

PubMed Central

Axenically propagated Entamoeba histolytica (HK9:NIH strain) were employed as starting material for the isoation of plasma membrane by a novel procedure. In the absence of known enzymatic markers, the externally disposed polypeptides of intact amoebae were iodinated and the incorporated label used to monitor membrane separation and recovery. 12 major plasma membrane polypeptides (12 x 10(3)-200 x 10(3) mol wt) were labeled and separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Each of these was a glycoprotein. Preincubation of amoebae with concanavalin A stabilized the plasma membranes as large sheets, facilitating its separation by low-speed centrifugation. Dissociation of the lectin with alpha-methyl mannoside, followed by additional homogenization led to vesiculation and further purification. The isolated plasma membrane was recovered in high yield (28%) and enriched 30-fold in terms of incorporated iodide. All iodinated surface glycoproteins of the intact organism were present in the plasma membrane fraction. A Ca++-dependent ATPase was enriched in the plasma membrane to a similar extent, but over one-half of the total activity was associated with internal, unlabeled membranes, suggesting a dual localization of this activity. The isolated plasma membrane was enriched in cholesterol and had a cholesterol:molar ratio of 0.87. It also contained larger amounts of an unusual phospholipid--ceramide aminoethyl phosphonate--a phospholipase-resistant species.

1980-01-01

263

Proteomic Mapping of Brain Plasma Membrane Proteins  

Microsoft Academic Search

Proteomics is potentially a powerful technology for eluci- dating brain function and neurodegenerative diseases. So far, the brain proteome has generally been analyzed by two-dimensional gel electrophoresis, which usually leads to the complete absence of membrane proteins. We de- scribe a proteomic approach for profiling of plasma mem- brane proteins from mouse brain. The procedure consists of a novel method

P. Aa. Nielsen; Jesper V. Olsen; Alexandre V. Podtelejnikov; Jens R. Andersen; Matthias Mann; Jacek R. Wisniewski

2005-01-01

264

Plasmodium falciparum Polypeptides Associated with the Infected Erythrocyte Plasma Membrane  

NASA Astrophysics Data System (ADS)

Plasmodium falciparum proteins associated with plasma membranes of infected erythrocytes were identified by using three techniques: (i) isolated plasma membranes from infected and uninfected erythrocytes were compared by gel electrophoresis and silver staining; (ii) isolated plasma membranes from cells metabolically labeled with [35S]methionine were assayed by gel electrophoresis; and (iii) uninfected and infected intact erythrocytes were surface-labeled by lactoperoxidase iodination, and the labeled polypeptides were compared by gel electrophoresis. The results from these experiments indicate that at least six parasite-derived polypeptides (Mr = > 240,000, 150,000, 55,000, 45,000, 35,000, and 20,000) are associated with the infected erythrocyte plasma membrane. At least four of these peptides (Mr = 55,000, 45,000, 35,000, and 20,000) may be exposed on the surface of the infected erythrocytes.

Stanley, Harold A.; Reese, Robert T.

1986-08-01

265

Membrane controlled anaerobic digestion  

NASA Astrophysics Data System (ADS)

In response to general shortages of energy, examination of the anaerboic digestion process as a potential source of a combustible, methane-rich fuel has intensified in recent years. It has been suggested that orgaic intermediates (such as fatty acids), produced during digestion, might also be recovered for use as chemical feedstocks. This investigation has been concerned with combining ultrafiltration separation techniques with anaerobic digestion for the development of a process in which the total production of acetic acid (the most valuable intermediate in anaerobic digestion) and methane are optimized. Enrichment cultures, able to utilize glucose as a sole carbon source, were adapted from sewage digesting cultures using conventional techniques. An ultrafiltration system was constructed and coupled to an anaerobic digester culture vessel which contained the glucose enrichment. The membrane controlled anaerobic digester appears to show promise as a means of producing high rates of both methane gas and acetic acid.

Omstead, D. R.

266

Evidence for spinodal decomposition and nucleation and growth mechanisms during membrane formation  

Microsoft Academic Search

The mechanisms of phase separation during membrane preparation were investigated by light scattering during immersion of cellulose acetate casting solutions in water \\/ acetone coagulation baths. Data obtained for casting solutions with a concentration range (11–17 wt% cellulose acetate in acetone) normally chosen for membrane preparation, coagulated in baths containing up to 65 wt% acetone, could be well fitted with

Suzana Pereira Nunes; Takashi Inoue

1996-01-01

267

Tonoplast Vesicles of Opposite Sidedness from Soybean Hypocotyls by Preparative Free-Flow Electrophoresis 1  

PubMed Central

Tonoplast vesicles were purified from a microsomal fraction isolated from etiolated soybean hypocotyls (Glycine max L.) by preparative free-flow electrophoresis. Marker enzyme determinations and immunoblot analysis against the vacuolar-ATPase confirmed the nature and the purity of the isolated membranes. A purified tonoplast fraction also was obtained by consecutive sucrose and glycerol centrifugation which was further resolved into two different populations of vesicles (TA and TB) by free-flow electrophoresis. The determination of the sidedness of these different vesicles included concanavalin A binding as an imposed label, NADH-ferricyanide oxidoreductase cytochemistry, and ATPase latency. The tonoplast fractions, obtained by consecutive sucrose and glycerol gradient centrifugations, were found to consist of a mixture of two populations of vesicles of opposite sidedness. The least electronegative fraction obtained by free-flow electrophoresis (TB) consisted predominantly of cytoplasmic side out tonoplast vesicles while a fraction of greater electronegativity (TA) contained the cytoplasmic side in tonoplast vesicles. The relative amounts of each type of vesicle varied with the method of homogenization. Razor blade chopping, Polytron, and Waring Blendor homogenization gave predominantly cytoplasmic side out vesicles, whereas mashing with a mortar and pestle gave nearly equal amounts of the two populations of membrane vesicles of different orientation. Images Figure 3 Figure 6 Figure 7

Canut, Herve; Brightman, Andrew; Boudet, Alain M.; Morre, D. James

1990-01-01

268

Application of capillary electrophoresis in glycoprotein analysis.  

PubMed

Capillary electrophoresis (CE) is a versatile analytical method used to characterize glycoproteins. We have used several modes of CE separation such as CE-SDS gel, imaged capillary isoelectric focusing (icIEF), and capillary zone electrophoresis (CZE) to study therapeutic glycoprotein products. CE-SDS gel is applied to characterize the glycan occupancy and number of glycosylation sites, and icIEF is used to study the charge heterogeneities due to sialic acids in glycoproteins. To further characterize the glycoprotein, removal of N-linked glycans is necessary and a CZE technique is employed to analyze each glycan moiety. Examples from a monoclonal antibody, erythropoietin, and granulocyte colony-stimulating factor are presented here to demonstrate the utility of these CE modes. The details of sample preparation and separation conditions for each CE mode are described in this chapter. PMID:23475720

Rustandi, Richard R; Anderson, Carrie; Hamm, Melissa

2013-01-01

269

Electrokinetic Flow and Dispersion in Capillary Electrophoresis  

NASA Astrophysics Data System (ADS)

Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care, and forensics. In capillary electrophoresis (which has evolved from its predecessor, slab-gel electrophoresis), the sample migrates through a single microcapillary instead of through the network of pores in a gel. A fundamental design problem is to minimize dispersion in the separation direction. Molecular diffusion is inevitable and sets a theoretical limit on the best separation that can be achieved. But in practice, there are a number of effects arising out of the interplay between fluid flow, chemistry, thermal effects, and electric fields that result in enhanced dispersion. This paper reviews the subject of fluid flow in such capillary microchannels and examines the various causes of enhanced dispersion that limit the efficiency of separation.

Ghosal, Sandip

2006-01-01

270

Capillary zone electrophoresis of pharmaceutical peptides.  

PubMed

In peptide analysis, capillary zone electrophoresis (CZE) gives complementary information to that obtained using high-performance liquid chromatography and capillary isotachophoresis. However, a prerequisite for the implementation of CZE for routine quality control purposes is a simple strategy quickly leading to an adequate separation system. A general approach towards the set-up of such systems is presented. A broad range of peptides were used as representative models, viz., adrenocorticotropic hormone (ACTH), the modified ACTH fragment Org 2766, endorphins, cholecystokinin and fragments thereof. In general, the pH and the concentration of the applied electrophoresis buffers are the most important parameters to be considered in the CZE of pharmaceutical peptides. PMID:8392515

Langenhuizen, M H; Janssen, P S

1993-05-28

271

Isolation and Control of Membrane Filter Degrading Microorganisms.  

National Technical Information Service (NTIS)

Reverse osmosis filtration is one of the most widely used methods of desalinization and cellulose acetate is the most common membrane material. The Roswell Test Facility (New Mexico) reverse osmosis testing program was plagued with premature failure of ce...

W. C. Lindemann

1981-01-01

272

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

273

A method and apparatus for continuous electrophoresis  

DOEpatents

A method and apparatus for conducting continuous separation of substances by electrophoresis are disclosed. The process involves electrophoretic separation combined with couette flow in a thin volume defined by opposing surfaces. By alternating the polarity of the applied potential and producing reciprocating short rotations of at least on of the surfaces relative to the other, small increments of separation accumulate to cause substantial, useful segregation of electrophoretically separable components in a continuous flow system.

Watson, J.S.

1990-01-01

274

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

Yeung, Edward S. (Ames, IA); Taylor, John A. (Nevada, IA)

1994-06-28

275

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figures.

Yeung, E.S.; Taylor, J.A.

1994-06-28

276

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figs.

Yeung, E.S.; Taylor, J.A.

1996-03-12

277

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

Yeung, Edward S. (Ames, IA); Taylor, John A. (Nevada, IA)

1996-03-12

278

Partial-filling affinity capillary electrophoresis  

Microsoft Academic Search

Partial-filling affinity capillary electrophoresis (PFACE) is used to examine the binding interactions between two model biological systems: D-Ala-D-Ala terminus peptides to the glycopeptide antibiotic vancomycin (Van) from Streptomyces orientalis, and arylsulfonamides to carbonic anhydrase B (CAB, EC 4.2.1.1, bovine erythrocytes). Using these two systems, modifications in the PFACE technique are demonstrated including flow-through PFACE (FTPFACE), competitive flow-through PFACE (CFTPFACE), on-column

Valerie Villareal; John Kaddis; Maryam Azad; Cecilia Zurita; Isba Silva; Lili Hernandez; Marcellus Rudolph; Julio Moran; Frank A. Gomez

2003-01-01

279

A method and apparatus for continuous electrophoresis  

DOEpatents

A method and apparatus for conducting continuous separation of substances by electrophoresis are disclosed. The process involves electrophoretic separation combined with couette flow in a thin volume defined by opposing surfaces. By alternating the polarity of the applied potential and producing reciprocating short rotations of at least on of the surfaces relative to the other, small increments of separation accumulate to cause substantial, useful segregation of electrophoretically separable components in a continuous flow system.

Watson, J.S.

1990-12-31

280

Method and apparatus for continuous electrophoresis  

DOEpatents

A method and apparatus for conducting continuous separation of substances by electrophoresis are disclosed. The process involves electrophoretic separation combined with couette flow in a thin volume defined by opposing surfaces. By alternating the polarity of the applied potential and producing reciprocating short rotations of at least one of the surfaces relative to the other, small increments of separation accumulate to cause substantial, useful segregation of electrophoretically separable components in a continuous flow system.

Watson, Jack S. (Knoxville, TN)

1992-01-01

281

Phorbol myristate acetate receptors in human polymorphonuclear neutrophils  

SciTech Connect

Resting or phorbol myristate acetate (PMA)-pretreated neutrophils were disrupted by nitrogen cavitation and were fractionated on Percoll density gradients to identify the subcellular location of PMA receptors. Receptors were found in the cytoplasm of resting cells; neither primary nor secondary granules bound (/sup 3/H)PMA, and the few binding sites located in non-granule membrane fractions appeared to reflect cytosolic contamination. Contrastingly, PMA-pretreated cells lost cytosolic receptors; > 80% of PMA-binding sites were associated with non-granule membranes. Protein kinase C activity similarly shifted from cytosol to membranes after PMA treatment. Indeed, protein kinase C and PMA receptors co-sedimented on Percoll gradients, co-eluted from Ultragel AcA 44 columns loaded with neutrophil cytoplasm, and were identically influenced by various phospholipids. Finally, PMA, mezerein, diacylglycerol, and dialkylglycerol activated protein kinase C with potencies that paralleled their respective abilities to stimulate neutrophil aggregation responses and inhibit (/sup 3/H)PMA binding to whole cells or cytosol. These results fit a model of stimulus-response coupling wherein exogenous PMA or endogenous diacylglycerol solvate in cellular membranes. Cytosolic protein kinase C binds to the intramembranous ligand, forming an active, membrane-associated complex that phosphorylates nearby elements involved in triggering aggregation and other responses.

Nishihira, J.; O'Flaherty, J.T.

1985-11-01

282

Development of nanofibrous cellulose acetate/gelatin skin substitutes for variety wound treatment applications.  

PubMed

The major component of fibrous extracellular matrix of dermis is composed of a complex combination of proteins and polysaccharides. Electrospun cellulose acetate/gelatin might be an effective simulator of the structure and composition of native skin and during this study, we electrospun cellulose acetate/gelatin membranes in various compositions and their performance as a scaffold for either skin tissue engineering or as a wound dressing was evaluated. Skin treatment products, whether tissue-engineered scaffolds or wound dressings, should be sufficiently hydrophilic to allow for gas and fluid exchange and absorb excess exudates while controlling the fluid loss. However, a wound dressing should be easily removable without causing tissue damage and a tissue-engineered scaffold should be able to adhere to the wound, and support cell proliferation during skin regeneration. We showed that these distinct adherency features are feasible just by changing the composition of cellulose acetate and gelatin in composite cellulose acetate/gelatin scaffolds. High proliferation of human dermal fibroblasts on electrospun cellulose acetate/gelatin 25:75 confirmed the capability of cellulose acetate/gelatin 25:75 nanofibers as a tissue-engineered scaffold, while the electrospun cellulose acetate/gelatin 75:25 can be a potential low-adherent wound dressing. PMID:23640859

Vatankhah, Elham; Prabhakaran, Molamma P; Jin, Guorui; Ghasemi Mobarakeh, Laleh; Ramakrishna, Seeram

2013-05-01

283

Vinyl acetate formation in the reaction of acetylene with acetic acid catalyzed by zinc acetate supported on porous carbon spheres  

NASA Astrophysics Data System (ADS)

A kind of porous carbon spheres (PCS) was prepared by the carbonization of poly(vinylidene chloride) synthesized by suspension polymerization. Structure analyses revealed the existence of bumps and holes on the surface of PCS. The PCS, with the pore size between 0.8-1.2 nm, could be used as the support of zinc acetate because of the regular shape, high specific surface area, and good mechanical strength. Vinyl acetate was produced from acetylene and acetic acid using the PCS-supported zinc acetate (PCS-Zn) under mild conditions. In a single-pass operation performed at 220°C, the conversions of acetic acid and acetylene reached 22.6 and 5.3% respectively while the activity of vinyl acetate formation was above 1000 g mol-1 h-1.

Yan, Feng-Wen; Guo, Cun-Yue; Yan, Fang; Li, Feng-Bo; Qian, Qing-Li; Yuan, Guo-Qing

2010-05-01

284

The purification of IgY from chicken egg yolk by preparative electrophoresis.  

PubMed

Chicken IgY has been purified from egg yolk by preparative electrophoresis on the Gradiflow, a system which has been employed for the purification of a wide range of proteins with high recovery and biological activity. Protein purification on the Gradiflow utilises electrophoresis with selected combinations of porous membranes and buffers. The purification of IgY was achieved by initial PEG lipid precipitation, then a single step Gradiflow run by a strategy based on the relatively high pI range of IgY compared to other egg yolk proteins. The IgY yields obtained from the delipidised supernatant are consistently greater than 80% by immunoassay. The purity of the IgY fraction compared favourably with IgY prepared using three commercial products. PMID:12880762

Gee, Sarah C; Bate, Irene M; Thomas, Theresa M; Rylatt, Dennis B

2003-08-01

285

The role of ion electrophoresis in electroporation-mediated molecular delivery  

NASA Astrophysics Data System (ADS)

Electroporation is a widely applied technique to deliver active molecules into the cellular compartment, to perform a variety of tasks such as gene therapy and directed stem cell differentiation. In this technique, an electric field transiently permeabilizes the cellular membrane to facilitate molecular exchange. While the permeabilization process is relatively well-understood, the transport mechanisms for molecular delivery are still under debate. In this work, the role of ion electrophoresis in electroporation-mediated molecular delivery is investigated using numerical simulations. The result indicates that ion electrophoresis is the dominant mode of transport in the delivery of small charged molecules. Furthermore, the achievable intracellular concentration is strongly influenced by the conductivity difference between the cytoplasm and the buffer, a phenomenon known as ``field-amplified sample stacking''. The result agrees well with the fluorescence measurement by Gabriel and Teissi'e (1999), and suggests a new possibility to simultaneously improve cell viability and efficiency in electroporation-mediated molecular delivery.

Li, Jianbo; Lin, Hao

2009-11-01

286

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

287

Electron transport in acetate-grown Methanosarcina acetivorans  

PubMed Central

Background Acetate is the major source of methane in nature. The majority of investigations have focused on acetotrophic methanogens for which energy-conserving electron transport is dependent on the production and consumption of H2 as an intermediate, although the great majority of acetotrophs are unable to metabolize H2. The presence of cytochrome c and a complex (Ma-Rnf) homologous to the Rnf (Rhodobacter nitrogen fixation) complexes distributed in the domain Bacteria distinguishes non-H2-utilizing Methanosarcina acetivorans from H2-utilizing species suggesting fundamentally different electron transport pathways. Thus, the membrane-bound electron transport chain of acetate-grown M. acetivorans was investigated to advance a more complete understanding of acetotrophic methanogens. Results A component of the CO dehydrogenase/acetyl-CoA synthase (CdhAE) was partially purified and shown to reduce a ferredoxin purified using an assay coupling reduction of the ferredoxin to oxidation of CdhAE. Mass spectrometry analysis of the ferredoxin identified the encoding gene among annotations for nine ferredoxins encoded in the genome. Reduction of purified membranes from acetate-grown cells with ferredoxin lead to reduction of membrane-associated multi-heme cytochrome c that was re-oxidized by the addition of either the heterodisulfide of coenzyme M and coenzyme B (CoM-S-S-CoB) or 2-hydoxyphenazine, the soluble analog of methanophenazine (MP). Reduced 2-hydoxyphenazine was re-oxidized by membranes that was dependent on addition of CoM-S-S-CoB. A genomic analysis of Methanosarcina thermophila, a non-H2-utilizing acetotrophic methanogen, identified genes homologous to cytochrome c and the Ma-Rnf complex of M. acetivorans. Conclusions The results support roles for ferredoxin, cytochrome c and MP in the energy-conserving electron transport pathway of non-H2-utilizing acetotrophic methanogens. This is the first report of involvement of a cytochrome c in acetotrophic methanogenesis. The results suggest that diverse acetotrophic Methanosarcina species have evolved diverse membrane-bound electron transport pathways leading from ferredoxin and culminating with MP donating electrons to the heterodisulfide reductase (HdrDE) for reduction of CoM-S-S-CoB.

2011-01-01

288

Evaluation of volatile eluents and electrolytes for high-performance liquid chromatography–electrospray ionization mass spectrometry and capillary electrophoresis–electrospray ionization mass spectrometry of proteins  

Microsoft Academic Search

Peptides and proteins were separated by capillary electrophoresis (CE) in fused-silica capillaries coated with an irreversibly adsorbed monolayer of derivatized polystyrene nanoparticles. Whereas phosphate buffer, pH 3.10, enabled the highly efficient separation of basic proteins with plate counts up to 1?400?000 m?1, volatile buffer components such as formic acid or acetic acid titrated with ammonia to the desired pH had

Christian G Huber; Andreas Premstaller; Gerald Kleindienst

1999-01-01

289

Global metabolic regulation analysis for Escherichia coli K12 based on protein expression by 2-dimensional electrophoresis and enzyme activity measurement  

Microsoft Academic Search

Regulation of the main metabolic pathways of Escherichia coli K12 was investigated based on 2-dimensional electrophoresis (2DE) and the measurement of enzyme activities. The cells were grown aerobically in different carbon sources, such as glucose, acetate, gluconate or glycerol. Microaerobic cultivation was also conducted with glucose as a carbon source. Fifty-two proteins could be identified based on 2DE, and 26

L. Peng; K. Shimizu

2003-01-01

290

Hereditary spherocytosis, elliptocytosis, and other red cell membrane disorders.  

PubMed

Hereditary spherocytosis and elliptocytosis are the two most common inherited red cell membrane disorders resulting from mutations in genes encoding various red cell membrane and skeletal proteins. Red cell membrane, a composite structure composed of lipid bilayer linked to spectrin-based membrane skeleton is responsible for the unique features of flexibility and mechanical stability of the cell. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Both these diseases can be readily diagnosed by various laboratory approaches that include red blood cell cytology, flow cytometry, ektacytometry, electrophoresis of the red cell membrane proteins, and mutational analysis of gene encoding red cell membrane proteins. PMID:23664421

Da Costa, Lydie; Galimand, Julie; Fenneteau, Odile; Mohandas, Narla

2013-05-09

291

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

292

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

293

Desmopressin Acetate (marketed as DDAVP Nasal Spray ...  

Center for Drug Evaluation (CDER)

... Desmopressin Acetate (marketed as DDAVP Nasal Spray, DDAVP Rhinal Tube, DDAVP, DDVP, Minirin, and Stimate Nasal Spray). ... More results from www.fda.gov/drugs/drugsafety/postmarketdrugsafetyinformationforpatientsandproviders

294

Putative ABC Transporter Responsible for Acetic Acid Resistance in Acetobacter aceti  

PubMed Central

Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid.

Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

2006-01-01

295

5?-Dihydro-vespertilin acetate  

PubMed Central

In the title compound, C24H36O4 [systematic name: (20S)-3?-acet­oxy-16?-hydr­oxy-22,23-bis­nor-5?,17?-cholano(22-16)lac­tone], the three six-membered rings adopt classical chair conformations, while the five-membered rings are in envelope conformations. The ester group attached to ring A is in an equatorial position. Rings A/B, B/C and C/D are trans-fused, whereas rings D/E are cis-fused. The structure is devoid of any classical hydrogen bonds. However, non-classical inter- and intra­molecular hydrogen-bonding inter­actions of the type C—H?O are present in the structure.

Benn, Michael; Vohra, Kanwal Nain; Parvez, Masood

2010-01-01

296

Capillary electrophoresis of anthraquinones from Cassia siamea.  

PubMed

The separation and determination of two anthraquinones, emodin and chrysophanol, and two bianthraquinones, cassiamin A and cassiamin B, were achieved by capillary electrophoresis (CE). The running electrolyte used in this method was 0.05 M hydroxypropyl-gamma-cyclodextrin in 0.1 M borate buffer (pH 9) containing 10% acetonitrile, with an applied voltage of 20 kV. Application of this technique in the determination of the main bianthraquinones, cassiamin A and cassiamin B, of Cassia siamea is demonstrated in this paper. PMID:12192145

Koyama, Junko; Morita, Izumi; Tagahara, Kiyoshi; Bakari, Jameelah; Aqil, Mohammad

2002-08-01

297

Identification of Culex species by electrophoresis.  

PubMed

This paper extends the usefulness of polyacrylamide gel electrophoresis to studies of mosquito taxonomy and mosquito vector ecology. Using a newly developed double staining technique, it is possible to unambiguously separate several species of Culex mosquitoes found in northern Indiana. These include Culex restuans, Culex pipiens pipiens, and Culex territans. Preliminary work indicates that Culex pipiens quinquefasciatus and Culex salinarius can also be identified by this method. This technique enables precise taxonomic identification of individual mosquitoes or pooled samples whether intact or damaged beyond identification by standard taxonomic methods. The small sample required (20 microliter) per pool leaves sufficient material for virus isolation techniques. PMID:907038

Saul, S H; Grimstad, P R; Craig, G B

1977-09-01

298

High speed DNA sequencing by capillary electrophoresis.  

PubMed

A major challenge of the Human Genome Initiative is the development of a rapid, accurate, and efficient DNA sequencing technology. A major limitation of current technology is the relatively long time required to perform the gel electrophoretic separations of DNA fragments produced in the sequencing reactions. We demonstrate here that it is possible to increase the speed of sequence analysis by over an order of magnitude by performing the electrophoresis and detection in ultra thin capillary gels. An instrument which utilizes these high speed separations to simultaneously analyze many samples will constitute a second generation automated DNA sequencer suitable for large-scale sequence analysis. PMID:2388826

Luckey, J A; Drossman, H; Kostichka, A J; Mead, D A; D'Cunha, J; Norris, T B; Smith, L M

1990-08-11

299

Microfabricated capillary array electrophoresis device and method  

DOEpatents

A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

Simpson, Peter C. (Oakland, CA); Mathies, Richard A. (Moraga, CA); Woolley, Adam T. (Belmont, MA)

2000-01-01

300

Identification of hemoglobin AC heterozygote status in a Malay family: a decision between hemoglobin electrophoresis and high performance liquid chromotography.  

PubMed

Thalassemia is a common public health problem among Malays. Hemoglobin C (Hb C) is a hemoglobin beta variant resulting from a single base mutation at the 6th position of the beta-globin gene leading to the substitution of glycine for glutamic acid. Hb C is commonly detected in West Africans and in African American but has not been reported in Malaysia. It can be falsely diagnosed as HbE trait in the Malaysian Thalassemia Screening Program which utilizes cellulose acetate hemoglobin electrophoresis. This is the first reported case of Hb AC heterozygote status in a Malay family, with unusual splenomegaly in one of the family members. PMID:17877232

Rosline, H; Roshan, T M; Ahmed, S A; Ilunihayati, I

2007-05-01

301

Microfluidic concentration of bacteria by on-chip electrophoresis  

PubMed Central

In this contribution, we present a system for efficient preconcentration of pathogens without affecting their viability. Development of miniaturized molecular diagnostic kits requires concentration of the sample, molecule extraction, amplification, and detection. In consequence of low analyte concentrations in real-world samples, preconcentration is a critical step within this workflow. Bacteria and viruses exhibit a negative surface charge and thus can be electrophoretically captured from a continuous flow. The concept of phaseguides was applied to define gel membranes, which enable effective and reversible collection of the target species. E. coli of the strains XL1-blue and K12 were used to evaluate the performance of the device. By suppression of the electroosmotic flow both strains were captured with efficiencies of up to 99%. At a continuous flow of 15??l/min concentration factors of 50.17?±?2.23 and 47.36?±?1.72 were achieved in less than 27?min for XL1-blue and K12, respectively. These results indicate that free flow electrophoresis enables efficient concentration of bacteria and the presented device can contribute to rapid analyses of swab-derived samples.

Puchberger-Enengl, Dietmar; Podszun, Susann; Heinz, Helene; Hermann, Carsten; Vulto, Paul; Urban, Gerald A.

2011-01-01

302

Hybrid reactive distillation systems for n-butyl acetate production from dilute acetic acid  

Microsoft Academic Search

The recovery of dilute acetic acid, regarding as a waste stream in many chemical and petrochemical processes, becomes an important issue due to economic and environmental awareness. In this work, a simulation study on the direct utilization of dilute acetic acid to produce n-butyl acetate via esterification with butanol in a reactive distillation is presented by using Aspen Plus. The

Amornchai Arpornwichanop; Kittipong Koomsup; Suttichai Assabumrungrat

2008-01-01

303

Ene diiodo acetals : stereoselective synthesis of ene hydroxy acetals. Handy access to non conjugated dienals  

Microsoft Academic Search

After halogen-metal exchange reaction followed by condensation with carbonyl compounds, ene diiodo acetal 1 allow the stereoselective synthesis of ene hydroxy acetals 2 with Z configuration, in a two step procedure. Moreover, after dehydration, the intermediate diene acetals 3–4, via an appropriated hydrolysis procedure, lead to pure non conjugated dienals 5.

B Bonnet; G Ple; L Duhamel

1998-01-01

304

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

305

Detection of glycoproteins in the Acanthamoeba plasma membrane  

SciTech Connect

In the present study the authors have shown that glycoproteins are present in the plasma membrane of Acanthamoeba castellanii by utilizing different radioactive labeling techniques. Plasma membrane proteins in the amoeba were iodinated by {sup 125}I-lactoperoxidase labeling and the solubilized radiolabeled glycoproteins were separated by lectin-Sepharose affinity chromatography followed by polyacrylamide gel electrophoresis. The periodate/NaB{sup 3}H{sub 4} and galactose oxidase/NaB{sup 3}H{sub 4} labeling techniques were used for labeling of surface carbohydrates in the amoeba. Several surface-labeled glycoproteins were observed in addition to a diffusely labeled region with M{sub r} of 55,000-75,000 seen on electrophoresis, which could represent glycolipids. The presence of glycoproteins in the plasma membrane of Acanthamoeba castellanii was confirmed by metabolic labeling with ({sup 35}S)methionine followed by lectin-Sepharose affinity chromatography and polyacrylamide gel electrophoresis.

Paatero, G.I.L. (Abo Akademi (Finland)); Gahmberg, C.G. (Univ. of Helsinki (Finland))

1988-11-01

306

Immobilized Metal Affinity Electrophoresis: A Novel Method of Capturing Phosphoproteins by Electrophoresis  

PubMed Central

An immobilized metal affinity electrophoresis (IMAEP) method is described here. In this method, metal ions are immobilized in a native polyacrylamide gel to capture phosphoproteins. The capture of phosphoproteins by IMAEP is demonstrated with immobilized metals like iron, aluminum, manganese, or titanium. In the case studies, phosphoproteins ?-casein, ?-casein, and phosvitin are successfully extracted from a protein mixture by IMAEP.

Lee, Bao-Shiang; Lasanthi, G.D.; Jayathilaka, P.; Huang, Jin-Sheng; Gupta, Shalini

2008-01-01

307

Cross-Linked Poly(Ester-Acetals).  

National Technical Information Service (NTIS)

The cross-linked products have utility as bonding agents for glass laminates. Certain novel soluble poly(ester-acetal) resins initially formed under alkaline conditions, under which the acetal groups appear to be inactive, may be crossed-linked by the add...

E. H. Pryde

1965-01-01

308

Fermentation characteristics of Fusariumoxysporum grown on acetate.  

PubMed

In this study, the growth characteristics of Fusariumoxysporum were evaluated in minimal medium using acetate or different mixtures of acetate and glucose as carbon source. The minimum inhibitory concentration (MIC) of acetic acid that F.oxysporum cells could tolerate was 0.8%w/v while glucose was consumed preferentially to acetate. The activity of isocitrate lyase was high when cells were grown on acetate and acetate plus glucose indicating an activation of the glyoxylate cycle. Investigation of the metabolic fingerprinting and footprinting revealed higher levels of intracellular and extracellular TCA cycle intermediates when F.oxysporum cells were grown on mixtures of acetate and glucose compared to growth on only glucose. Our data support the hypothesis that a higher flux through TCA cycle during acetate consumption could significantly increase the pool of NADH, resulting in the activation of succinate-propionate pathway which consumes reducing power (NADH) via conversion of succinate to propionyl-CoA and produce propionate. PMID:18304808

Panagiotou, Gianni; Pachidou, Fotini; Petroutsos, Dimitris; Olsson, Lisbeth; Christakopoulos, Paul

2008-03-04

309

Floating resistivity detector for microchip electrophoresis.  

PubMed

A newly developed conductivity detector, the floating resistivity detector (FRD), for microchip electrophoresis was introduced in this work. The detector design permits decoupling of the detection circuit from the high separation voltage without compromising separation efficiency. This greatly simplifies the integration of microchip electrophoresis systems. Its method of detection relies on platinum electrodes being dipped in two buffer-filled branched detection probe reservoirs on the microchip device. In this way, analytes passing through the detection window will not pass through and subsequently adsorb onto the electrodes, alleviating problems of electrode fouling due to analyte contamination and surface reactions. A customized microchip design was proposed and optimized stepwise for the new FRD system. Each branched detection probe was determined to be 4.50 mm long with a 0.075 mm detection window gap between them. The distance between the detection window and buffer waste reservoir was determined to be 1.50 mm. The optimized microchip design was subsequently used in the analysis of four groups of analytes - inorganic cations, amino acids, aminoglycosides antibiotics, and biomarkers. Based on the preliminary results obtained, the detection limits were in the range of 0.4-0.7 mg/L for the inorganic cations and 1.5-15 mg/L for the amino compounds. PMID:18072226

Tay, Elaine Teng Teng; Law, Wai Siang; Sim, Steven Poh Chuen; Feng, Huatao; Zhao, Jian Hong; Li, Sam Fong Yau

2007-12-01

310

Boronate affinity saccharide electrophoresis: A novel carbohydrate analysis tool  

Microsoft Academic Search

The incorporation of specialised carbohydrate affinity ligand methacrylamido phenylboronic acid in polyacrylamide gels for fluorophore-assisted carbohydrate electrophoresis greatly improved the effective separation of saccharides that show similar mobilities in standard electrophoresis. Polyacrylamide gel electrophoresis using methacrylamido phenylboronic acid in low loading (typically 0.5-1% dry weight) was unequivocally shown to alter retention of labelled saccharides depending on their boronate affinity. While

J. M. H. van den Elsen; T. R. Jackson; J. S. Springall; D. Rogalle; N. Masurnoto; H. C. Li; F. D'Hooge; S. P. Perera; A. T. A. Jenkins; T. D. James; J. S. Fossey

2008-01-01

311

Capillary electrophoresis for the detection of Fragile X expanded alleles.  

PubMed

Capillary electrophoresis is an analytical technique that separates ions based on their electrophoresis mobility with the use of an applied voltage. Capillary electrophoresis is used most predominantly in nuclear acid fragment analysis as well as DNA sequencing because it gives faster results and provides high resolution separation. Here we describe an application using capillary electrophoreses for screening the Fragile X expanded alleles to demonstrate the application. PMID:22976108

Mao, Rong; Bayrak-Toydemir, Pinar; Lyon, Elaine

2013-01-01

312

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

313

Dye removal, catalytic activity and 2D crystallization of chloroplast H +ATP synthase purified by blue native electrophoresis  

Microsoft Academic Search

The proton-ATP synthase of thylakoid membranes from spinach chloroplasts (CFOF1) and its subcomplexes CFO and CF1 were isolated by blue native electrophoresis (BN-PAGE) [Neff, D. and Dencher, N.A. (1999) Biochem. Biophys. Res. Commun. 259, 569–575] and subsequently electroeluted from the gel. A method was developed to remove most of the dye Coomassie G-250 (CBG) using gel filtration, a prerequisite for

Ansgar Poetsch; Dirk Neff; Holger Seelert; Hermann Schägger; Norbert A. Dencher

2000-01-01

314

Recent advances in microchip electrophoresis for amino acid analysis.  

PubMed

With the maturation of microfluidic technologies, microchip electrophoresis has been widely employed for amino acid analysis owing to its advantages of low sample consumption, reduced analysis time, high throughput, and potential for integration and automation. In this article, we review the recent progress in amino acid analysis using microchip electrophoresis during the period from 2007 to 2012. Innovations in microchip materials, surface modification, sample introduction, microchip electrophoresis, and detection methods are documented, as well as nascent applications of amino acid analysis in single-cell analysis, microdialysis sampling, food analysis, and extraterrestrial exploration. Without doubt, more applications of microchip electrophoresis in amino acid analysis may be expected soon. PMID:23436170

Ou, Gaozhi; Feng, Xiaojun; Du, Wei; Liu, Xin; Liu, Bi-Feng

2013-02-24

315

Physicochemical characterization and antibacterial property of chitosan acetates  

Microsoft Academic Search

In a new approach to the preparation of solid chitosan acetate, the dependence of solubility of chitsoan acetate on the mole ratio of acetic acid to GlcN residues of chitosan was evaluated from turbidity. The structure of the product chitosan acetate was characterized by titration and FT-IR. It was demonstrated that the chitosan acetate with high solubility retained the structure

Yan Li; Xi Guang Chen; Nan Liu; Cheng Sheng Liu; Chen Guang Liu; Xiang Hong Meng; Le Jun Yu; John F. Kenendy

2007-01-01

316

Membrane stabilizer  

DOEpatents

A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material. 10 figs.

Mingenbach, W.A.

1988-02-09

317

Electrospun cellulose nanofiber as affinity membrane  

Microsoft Academic Search

The objective of this work is to study the feasibility of applying cellulose nanofiber membrane prepared by electrospinning as affinity membrane. Cellulose acetate (CA) solution (0.16g\\/ml) in a mixture solvent of acetone\\/DMF\\/trifluoroethylene (3:1:1) was electrospun into nonwoven fiber mesh with the fiber diameter ranging from 200nm to 1?m. The CA nanofiber mesh was heat treated under 208°C for 1h to

Zuwei Ma; M. Kotaki; S. Ramakrishna

2005-01-01

318

Desvenlafaxinium chloranilate ethyl acetate solvate  

PubMed Central

In the cation of the title compound, C16H26NO2 +·C6HCl2O4 ?·C4H8O2, the 1-hy­droxy-cyclo­hexyl ring adopts a slightly distorted chair conformation. The dihedral angle between the mean planes of the 1-hy­droxy­cyclo­hexyl and 4-hy­droxy­phenyl rings is 84.0?(8)°. In the anion, the hydroxyl H atom is twisted slightly out of the ring plane with a C—C—O—H torsion angle of ?171.9°. Disorder was modeled for the methyl group of the acetate group in the solvate with an occupancy ratio of 0.583?(15): 0.417?(15). In the crystal, O—H?O hydrogen bonds are observed between cations and between cations and anions, while bifuricated N—H?(O,O) cation–anion hydrogen bonds are also present, forming chains along [010] and [100]. In addition weak cation–anion and cation–solvate C—H?O inter­actions occur.

Kaur, Manpreet; Jasinski, Jerry P.; Butcher, Ray J.; Yathirajan, H. S.; Byrappa, K.

2013-01-01

319

Pervaporation as interface between solid samples and capillary electrophoresis. Determination of biogenic amines in food.  

PubMed

A fully automated system for solid sample analysis has been developed by on-line coupling a pervaporation module with a capillary electrophoresis system using as interface a flow injection manifold and a modified capillary electrophoresis vial. The pervaporator allows leaching, formation of the volatile analytes and their removal by evaporation and diffusion through a membrane. The isolated analytes are on-line injected into the capillary electrophoresis system meanwhile the solid matrix remains in the pervaporator. By this approach biogenic amines have been determined in fish, meat and sausage. The detection limits (LOD) ranged between 0.2 and 0.6microg/ml, the quantification limits between 0.7 and 1.9microg/ml and the linear dynamic between 0.4 and 400microg/ml. The precision, expressed as relative standard deviation (RSD), ranged between 0.76 and 4.21% for repeatability and between 1.12 and 4.78% for within laboratory reproducibility. The errors, expressed as RSD for all compounds, ranged between 1.64 and 3.42%. The optimal pervaporation time and that necessary for the individual separation/detection of the target analytes are 14 and 12min, respectively. The analysis frequency is higher than 3h(-1) and the sample size 0.1g. A two-tailed t-test, used to compare the proposed method with that based on HPLC, yielded similar results for nine different samples. PMID:16483589

Ruiz-Jiménez, J; Luque de Castro, M D

2006-02-17

320

A microchannel electrophoresis DNA sequencing system  

SciTech Connect

In order to increase the DNA sequencing throughput of the Joint Genome Institute, we have developed a microchannel electrophoresis system. The critical new and unique elements of this system include 1) a process for the production of arrays of 96 and 384 microchannels on bonded glass substrates up to 14 x 58 cm and 2) new sieving media for high resolution and high speed separations. With custom fabrication apparatus, microchannels are etched in a borosilicate substrate, and then fusion bonded to a top substrate 1.1 mm thick that has access holes formed in it. SEM examination shows a typical microchannel to be 40 micrometers deep x 180 micrometers wide by 46 cm long. This technology offers significant advantages over discrete capillaries or conventional slab-gel approaches. High throughput DNA sequencing with over 550 base pairs resolution has been achieved in roughly half the time of conventional sequencers. In February 1999, we begin a pre-production evaluation protocol for the microchannel and for three glass capillary electrophoresis systems (two from industry and one developed by Lawrence Berkeley National Laboratory for the Joint Genome Institute). In order to utilize these instruments for DNA production sequencing, we have been evaluating and implementing software to convert raw electropherograms into called DNA bases with an associated probability of error. Our original intent was to utilize the DNA base calling software known as Plan and Phred developed by the University of Washington. This software has been outstanding for our slab gel electrophoresis systems currently in the production facility. In our tests and evaluations of this software applied to microchannel data, we observed that the electropherograms are of a different statistical and underlying signal structure compared to slab gels. Even with substantial modifications to the software, base calling performance was not satisfactory for the microchannel data. In this paper, we will present o The microchannel DNA sequencing system and show the advantages compared to current slab gel and capillary systems. o The signal processing modules needed including correction of multiple wavelength channels, signal averaging, non-uniform sampling, variable DNA mobility, and peak shape and spreading effects. o A comparison of the DNA base signatures in the raw data of microchannels vs. slab gels including some simple modeling results. This will be propagated through the base calling software to show the impact on DNA sequencing.

Madabhushi, R S; Warth, T; Balch, J W; Bass, M; Brewer, L R; Copeland, A C; Davidson, J C; Fitch, J P; Kegelmeyer, L M; Kimbrough, J R; McCready, P; Nelson, D; Pastrone, R L; Richardson, P M; Swierkowski, S P; Tarte, L A; Vainer, M

1999-01-01

321

Chip electrophoresis of gelatin-based nanoparticles.  

PubMed

Recently, biodegradable nanoparticles received increasing attention for pharmaceutical applications as well as applications in the food industry. With the current investigation we demonstrate chip electrophoresis of fluorescently (FL) labeled gelatin nanoparticles (gelatin NPs) on a commercially available instrument. FL labeling included a step for the removal of low molecular mass material (especially excess dye molecules). Nevertheless, for the investigated gelatin NP preparation two analyte peaks, one very homogeneous with an electrophoretic net mobility of ? = -24.6 ± 0.3 × 10(-9) m(2) /Vs at the peak apex (n = 17) and another more heterogeneous peak with ? between approximately -27.2 ± 0.2 × 10(-9) m(2) /Vs and -36.6 ± 0.2 × 10(-9) m(2) /Vs at the peak beginning and end point (n = 11, respectively) were recorded. Filtration allowed enrichment of particles in the size range of approximately 35 nm (pore size employed for concentration of gelatin NPs) to 200 nm (pore size employed during FL labeling). This corresponded to the very homogeneous peak linking it to gelatin NPs, whereas the more heterogeneous peak probably corresponds to gelatin not cross-linked to such a high degree (NP building blocks). Several further gelatin NP preparations were analyzed according to the same protocol yielding peaks with electrophoretic net mobilities between -23.3 ± 0.3 × 10(-9) m(2) /Vs and -28.9 ± 0.2 × 10(-9) m(2) /Vs at peak apexes (n = 15 and 6). Chip electrophoresis allows analyte separation in less than two minutes (including electrophoretic sample injection). Together with the high sensitivity of the FL detection - the LOD as derived for the first main peak of the applied dye from the threefold standard deviation of the background noise values 80 pM for determined separation conditions - this leads to a very promising high throughput separation technique especially for the analysis of bionanoparticles. For gelatin NP preparations, chip electrophoresis allows for example the comparison of preparation batches concerning the amount of NPs and gelatin building blocks as well as the indirect assessment of the degree of gelatin cross-linking (from obtained FL signals). PMID:23712750

Weiss, Victor U; Lehner, Angela; Grombe, Ringo; Marchetti-Deschmann, Martina; Allmaier, Günter

2013-08-01

322

Acetate in mixotrophic growth medium affects photosystem II in Chlamydomonas reinhardtii and protects against photoinhibition.  

PubMed

Chlamydomonas reinhardtii is a photoautotrophic green alga, which can be grown mixotrophically in acetate-supplemented media (Tris-acetate-phosphate). We show that acetate has a direct effect on photosystem II (PSII). As a consequence, Tris-acetate-phosphate-grown mixotrophic C. reinhardtii cultures are less susceptible to photoinhibition than photoautotrophic cultures when subjected to high light. Spin-trapping electron paramagnetic resonance spectroscopy showed that thylakoids from mixotrophic C. reinhardtii produced less (1)O2 than those from photoautotrophic cultures. The same was observed in vivo by measuring DanePy oxalate fluorescence quenching. Photoinhibition can be induced by the production of (1)O2 originating from charge recombination events in photosystem II, which are governed by the midpoint potentials (Em) of the quinone electron acceptors. Thermoluminescence indicated that the Em of the primary quinone acceptor (QA/QA(-)) of mixotrophic cells was stabilised while the Em of the secondary quinone acceptor (QB/QB(-)) was destabilised, therefore favouring direct non-radiative charge recombination events that do not lead to (1)O2 production. Acetate treatment of photosystem II-enriched membrane fragments from spinach led to the same thermoluminescence shifts as observed in C. reinhardtii, showing that acetate exhibits a direct effect on photosystem II independent from the metabolic state of a cell. A change in the environment of the non-heme iron of acetate-treated photosystem II particles was detected by low temperature electron paramagnetic resonance spectroscopy. We hypothesise that acetate replaces the bicarbonate associated to the non-heme iron and changes the environment of QA and QB affecting photosystem II charge recombination events and photoinhibition. PMID:23791666

Roach, Thomas; Sedoud, Arezki; Krieger-Liszkay, Anja

2013-06-17

323

Lipidomic Profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii Reveals Critical Changes in Lipid Composition in Response to Acetic Acid Stress  

PubMed Central

When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L?1, while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L?1 acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large rearrangements in its lipid profile.

Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

2013-01-01

324

Lipidomic Profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii Reveals Critical Changes in Lipid Composition in Response to Acetic Acid Stress.  

PubMed

When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L(-1), while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L(-1) acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large rearrangements in its lipid profile. PMID:24023914

Lindberg, Lina; Santos, Aline Xs; Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

2013-09-04

325

Permeability of Lipid Bilayer Membranes to Organic Solutes  

Microsoft Academic Search

A sensitive fluorescence technique was used to measure transport of organic solutes through lipid bilayer membranes and to relate permeability to the functional groups of the solute, lipid composition of the membrane, and pH of the medium. Indole derivatives having ethanol, acetate, or ethylamine in the 3-position, representing neutral, acidic, and basic solutes, respectively, were the primary models. The results

ROSS C. BEAN; WILLIAM C. SHEPHERD; HAKCHILL CHAN

1968-01-01

326

Research and Development of New and Improved Cellulose Ester Membranes.  

National Technical Information Service (NTIS)

The goal of the program was the preparation of membranes for demineralizing brackish waters and seawater with a retention of at least 80% of their initial flux after one year of operation. Two membranes, one made from a blend of cellulose acetates and one...

A. J. Secchi C. W. Saltonstall D. L. Hoernschemeyer O. S. Schaeffler

1973-01-01

327

Hybrid molecularly imprinted membranes for targeted bisphenol derivatives  

Microsoft Academic Search

Bisphenol A (BPA) imprinted polymer, which was prepared with BPA methacrylate and divinyl benzene (DVB), was hybridized in porous membrane scaffolding of polystyrene (PS), cellulose acetate (CA), nylon 66 (Ny) and polysulfone (PSf) by phase inversion process. Resultant hybrid imprinted membranes showed high capture ability to the BPA having 148, 142 and 158?mol\\/g for the hybrid CA, Ny and PSf

Kohei Takeda; Takaomi Kobayashi

2006-01-01

328

DNA Chain Dynamics in Surface Electrophoresis  

NASA Astrophysics Data System (ADS)

We have studied the dynamics of DNA chains on surface in order to attain a more detailed understanding of the mechanism of surface electrophoresis. We have measured the diffusion and mobility of DNA chains on hydrophilic silicon surface by using Laser Fluorescence Microscope. The result showed that the diffusion on surface was minimum, while it was much bigger in buffer and the mobility increased linearly with electric field within certain range. We also directly observed single chain motion of linear, circular and supercoiled DNA by CCD camera. The motion of different DNA chains we observed was consistent with changes in chain conformation due to surface attraction. Neutron reflectivity was also performed on DNA chain adsorption in an electric field, from which the loop size of adsorbed DNA chain can be determined. These data will be compared to a theoretical model of the individual chain motion on an attractive surface. Supported by NSF-GARCIA center

Li, Bingquan; Fang, Xiaohua; Seo, Youngsoo; Samuilov, Vladimir; Rafailovich, Miriam; Sakolov, Jonathan

2004-03-01

329

Computational modeling of traveling wave electrophoresis  

NASA Astrophysics Data System (ADS)

Traveling wave electrophoresis (TWE) is a microfluidic separation technique in which electrodes flanking a microchannel apply a traveling potential wave along the channel. Charged particles, including small molecules, proteins, and nanoparticles are differentially transported along the channel at a rate dependent on their mobility. TWE is ideally suited for application in lab-on-a-chip and field deployed sensor systems. In order to fully exploit this technology, a series of computational models have been developed, including 1-dimensional and 2-dimensional models. These models allow for testable predictions of single-particle motion, and the effects of factors such as Ph and concentration upon separation efficiency. Efforts to include diffusive components within the model, and to consider the motion of bands, rather than single particles will be discussed.

Correll, Robert; Schiffbauer, Jarrod; Carroll, Lloyd

2012-02-01

330

Dating silk by capillary electrophoresis mass spectrometry.  

PubMed

A new capillary electrophoresis mass spectrometry (CE-MS) technique is introduced for age estimation of silk textiles based on amino acid racemization rates. With an L to D conversion half-life of ~2500 years for silk (B. mori) aspartic acid, the technique is capable of dating silk textiles ranging in age from several decades to a few-thousand-years-old. Analysis required only ~100 ?g or less of silk fiber. Except for a 2 h acid hydrolysis at 110 °C, no other sample preparation is required. The CE-MS analysis takes ~20 min, consumes only nanoliters of the amino acid mixture, and provides both amino acid composition profiles and D/L ratios for ~11 amino acids. PMID:21913691

Moini, Mehdi; Klauenberg, Kathryn; Ballard, Mary

2011-09-13

331

Characterization of humic substances by capillary electrophoresis.  

PubMed

Capillary electrophoresis was used for the separation of humic acid (HA) from peat, soil, and vermicompost. The electropherograms show the presence of at least three peaks eluted between 6 and 11 min for all HA. The best analysis resolution was obtained with the use of borate buffers at pH 8.9. The HA analyzed have structural and charge similarity, which increases the difficulty of separation. Therefore, the shape of the peaks is broad and the CE profiles of all HA are similar. It is reasonable to assume that the broad band in the three regions is due to the acidic groups that have a similar structure. By comparing the results obtained for HA extracted from soil, peat, vermicompost, and the commercial sample, HA from peat had the major carbon content. PMID:10812428

Landgraf, M D; Javaroni, R de C; Rezende, M O

332

Characterization of bovine collagens using capillary electrophoresis.  

PubMed

A capillary electrophoresis method was developed and characterized for analyzing the spectrum of collagen subspecies in collagen preparations. The Bio-Rad CE-SDS protein kit was used for the dynamic sieving separation of collagen subspecies in this CE method (DSCE). The optimized method utilized a 36 cm (or 24 cm) x 50 microm uncoated capillary, electrophoretic injection at 10 kV for 10 s, a run voltage of 15 kV, a capillary temperature of 20 degrees C, and UV detection at 220 nm. A preliminary validation of the method was performed. The assay had good repeatability (RSDs for peaks were 15%), and responses were linear for assay solutions with collagen concentrations from 0.125 to 1.25 mg/ml. The DSCE electropherogram of bovine skin collagen provided a profile of subspecies similar in number and relative abundance to that generated by scanning of Coomassie-stained SDS-PAGE gels. PMID:10857565

Chang, P; Kuan, S; Eberlein, G; Burke, D; Jones, R

2000-07-01

333

Automated DNA electrophoresis, hybridization and detection  

SciTech Connect

A fully automated, computer controlled system for nucleic acid hybridization analysis has been devised and constructed. In practice, DNA is digested with restriction endonuclease enzyme(s) and loaded into the system by pipette; /sup 32/P-labelled nucleic acid probe(s) is loaded into the nine hybridization chambers. Instructions for all the steps in the automated process are specified by answering questions that appear on the computer screen at the start of the experiment. Subsequent steps are performed automatically. The system performs horizontal electrophoresis in agarose gel, fixed the fragments to a solid phase matrix, denatures, neutralizes, prehybridizes, hybridizes, washes, dries and detects the radioactivity according to the specifications given by the operator. The results, printed out at the end, give the positions on the matrix to which radioactivity remains hybridized following stringent washing.

Zapolski, E.J.; Gersten, D.M.; Golab, T.J.; Ledley, R.S.

1986-05-01

334

Hybrid slab-microchannel gel electrophoresis system  

DOEpatents

A hybrid slab-microchannel gel electrophoresis system is described. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate. 4 figs.

Balch, J.W.; Carrano, A.V.; Davidson, J.C.; Koo, J.C.

1998-05-05

335

21 CFR 172.833 - Sucrose acetate isobutyrate (SAIB).  

Code of Federal Regulations, 2010 CFR

...3 2010-01-01 2009-04-01 true Sucrose acetate isobutyrate (SAIB). 172.833...CONSUMPTION Multipurpose Additives § 172.833 Sucrose acetate isobutyrate (SAIB). Sucrose acetate isobutyrate may be safely used in...

2010-01-01

336

21 CFR 172.833 - Sucrose acetate isobutyrate (SAIB).  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Sucrose acetate isobutyrate (SAIB). 172.833...CONSUMPTION Multipurpose Additives § 172.833 Sucrose acetate isobutyrate (SAIB). Sucrose acetate isobutyrate may be safely used in...

2009-04-01

337

Two-dimensional Gel Electrophoresis (2DE)  

NASA Astrophysics Data System (ADS)

The chemical compounds, which are present in the environment, increasingly cause bad effects on health. The most serious effects are tumors and various mutations at the cellular level. Such compounds, from the analytical point of view, can serve the function of biomarkers, constituting measurable changes in the organism's cells and biochemical processes occurring therein. The challenge of the twenty-first century is therefore searching for effective and reliable methods of identification of biomarkers as well as understanding bodily functions, which occur in living organisms at the molecular level. The irreplaceable tool for these examinations is proteomics, which includes both quality and quantity analysis of proteins composition, and also makes it possible to learn their functions and expressions. The success of proteomics examinations lies in the usage of innovative analytical techniques, such as electromigration technique, two-dimensional electrophoresis in polyacrylamide gel (2D PAGE), liquid chromatography, together with high resolution mass spectrometry and bio-informatical data analysis. Proteomics joins together a number of techniques used for analysis of hundreds or thousands of proteins. Its main task is not the examination of proteins inside the particular tissue but searching for the differences in the proteins' profile between bad and healthy tissues. These differences can tell us a lot regarding the cause of the sickness as well as its consequences. For instance, using the proteomics analysis it is possible to find relatively fast new biomarkers of tumor diseases, which in the future will be used for both screening and foreseeing the course of illness. In this chapter we focus on two-dimensional electrophoresis because as it seems, it may be of enormous importance when searching for biomarkers of cancer diseases.

K?odzi?ska, Ewa; Buszewski, Bogus?aw

338

Capillary electrophoresis of 99mtechnetium radiopharmaceuticals.  

PubMed

Diagnostically used 99mTc kit radiopharmaceuticals were analyzed using capillary zone electrophoresis with radioactivity detection: 99mTc-bis(bis(2-ethyloxyethyl)phosphino)ethane (99mTc-Myoview, 99mTc-Tetrofosmin), 99mTc-trans(1,2-bis(dehydro-2,2,5,5,-tetramethyl-3-furanone-4-methylene- amino)ethane)-tris(3-methoxy-1-propyl)phosphine) (99mTc-Technescan Q12, 99mTc-Furifosmin), 99mTc-methoxyisobutylisonitrile (99mTc-MIBI), 99mTc-L,L-ethylenecysteine diethylester dimer (99mTc-ECD), 99mTc-d,1-hexamethylene propyleneamine oxime (99mTc-HMPAO), 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA), 99mTc-ethylene hepatobiliary iminodiacetic acid (99mTc-EHIDA), 99mTc-L,L-ethylenecysteine dimer (99mTc-EC), 99mTc-mercaptoacetylglycylglycylglycine (99mTc-MAG3), 99mTc-dimercaptosuccinic acid (99mTc-DMSA), 99mTc-methylene diphosphonate (99mTc-MDP) and 99mNaTcO4. A pressure-driven capillary zone electrophoresis was employed to detect small anions of high electrophoretic mobility and cations within one run. Effective 99mTc complex charges could be determined by a neutral internal standard. All complexes showed the expected electrophoretic behaviours in view of their charges. Pure products were obtained for the majority of the studied complexes. In the case of 99mTc-Q12, 99mTc-EHIDA and 99mTc-MDP, complex mixtures were detected. The high potential of CE for the analysis of 99mTc radiopharmaceuticals could be shown. PMID:10219679

Jankowsky, R; Noll, B; Johannsen, B

1999-03-19

339

Modification of membrane surface for anti-biofouling performance: Effect of anti-adhesion and anti-bacteria approaches  

Microsoft Academic Search

Membrane biofouling refers to the undesirable accumulation (attachment and growth) of microorganisms on a membrane surface, and has been a major problem in the application of membrane technology in water and wastewater treatment. In this study, the surface of a base membrane made of chitosan\\/cellulose acetate blend was modified by reacting with heparin, quaternary ammonium or being immobilized with silver

C. X. Liu; D. R. Zhang; Yi He; X. S. Zhao; Renbi Bai

2010-01-01

340

Alterations of the Immunological Specificity of Plasma Membranes from Cells Infected with Marek's Disease and Turkey Herpes Viruses  

Microsoft Academic Search

SUMMARY Highly purified plasma membranes were isolated from chicken embryo fibro- blasts infected with Marek's disease virus (MDV) or turkey herpes virus (HVT). The purification was monitored by the incorporation of fucose and marker en- zymes specific for plasma membranes. Polyacrylamide gel electrophoresis showed that the membrane preparations contained two new virus-induced proteins. When reacted in the double immunodiffusion test

O. R. Kaaden; B. Dietzschold

1974-01-01

341

High-Throughput Capillary-Electrophoresis Analysis of the Contents of Single Mitochondria  

PubMed Central

We present a technique for labeling the contents of acidic organelles and rapidly releasing, separating, and detecting their labeled contents with laser-induced fluorescence. We have performed solution-phase separation of the contents of single mitochondria and single 100 nm vesicles, which represents a demonstration of an analyzed volume of ~1 attoliter. Our strategy to label the acidic contents of the mitochondrion relies on the use of the membrane-permeable dye, Oregon Green diacetate succinimidyl ester, and a membrane-permeable base to raise intra-mitochondrial pH. In order to measure the contents, we utilized a glass microfluidic chip and high voltage gradient for millisecond capillary-electrophoresis separation after single-mitochondrion photolysis. We observed heterogeneity among a population of mitochondria with respect to a constituent chemical component.

Allen, Peter B.; Doepker, Byron R.; Chiu, Daniel T.

2009-01-01

342

Isolation of Outer Membrane of Synechocystis sp. PCC 6803 and Its Proteomic Characterization  

Microsoft Academic Search

In this report, we describe a newly developed method for isolating outer membranes from Synechocystis sp. PCC 6803 cells. The purity of the outer membrane fraction was verified by immunoblot analysis using antibodies against membrane-specific marker proteins. We investigated the protein composition of the outer membrane using two- dimensional gel electrophoresis and matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry followed by

Fang Huang; Erik Hedman; Christiane Funk; Thomas Kieselbach; Wolfgang P. Schroder; Birgitta Norling

2004-01-01

343

Protein gel electrophoresis in the undergraduate physics laboratory  

Microsoft Academic Search

We describe an undergraduate laboratory experiment in protein gel electrophoresis that uses readily available apparatus and materials. The separation of a mixture of stained proteins by gel electrophoresis was videotaped. Position-time data for the proteins generated from analysis of digitized videotape images allowed for calculation of protein terminal velocities. The dependence of protein terminal velocity on molar mass was determined

Danny G. Miles; David W. Bushman; Zhong-Ying Chen

2005-01-01

344

Processing of DNA and Protein Electrophoresis Gels by Image Analysis  

Microsoft Academic Search

With recent legislation allowing for the registration of new cultivars, the analysis of DNA and protein electrophoresis gels is becoming increasingly important for cultivar identification. DNA fragments or proteins of different molecular weights are separated using electrophoresis, giving a series of bands with positions corresponding to the molecular weight. Image analysis of the gels removes much of the subjectivity of

Donald G. Bailey; C. Bruce Christie

345

Advances in agarose gel electrophoresis of serum lipoproteins  

Microsoft Academic Search

Agarose gel electrophoresis has been extensively employed by researchers to gain a greater understanding of lipoprotein biology and its relationship to cardiovascular disease. Advances in this technique have been made in the visualization and quantitation of separated lipoproteins, in the use of agarose gel electrophoresis for detection and quantitation of apolipoproteins of the separated lipoproteins, and in the detection of

Phillip Greenspan; Fei-wen Mao; Beung-Ho Ryu; Robert L. Gutman

1995-01-01

346

Capillary electrophoresis and its application in the clinical laboratory  

Microsoft Academic Search

Over the past 10 years, capillary electrophoresis (CE) is an analytical tool that has shown great promise in replacing many conventional clinical laboratory methods, especially electrophoresis and high performance liquid chromatography (HPLC). The main attraction of CE was that it was fast, used small amounts of sample and reagents, and was extremely versatile, being able to separate large and small

John R Petersen; Anthony O Okorodudu; Amin Mohammad; Deborah A Payne

2003-01-01

347

Capillary electrophoresis and its application in the clinical laboratory  

Microsoft Academic Search

Over the past 10 years, capillary electrophoresis (CE) is an analytical tool that has shown great promise in replacing many conventional clinical laboratory methods, especially electrophoresis and high performance liquid chromatography (HPLC). The main attraction of CE was that it was fast, used small amounts of sample and reagents, and was extremely versatile, being able to separate large and small

John R. Petersen; Anthony O. Okorodudu; Amin Mohammad; Deborah A. Payne

348

Control of the Staining Procedure after Paper Electrophoresis  

Microsoft Academic Search

WHEN quantitative techniques are attempted for the analysis of serum proteins separated by electrophoresis on filter paper, it is recognized that the staining procedure, followed by removing the surplus stain, constitutes sources of error. In order to get more satisfactory reproducibility we apply on each paper strip (after electrophoresis but before staining) 0.02 ml. of a 0.05 per cent solution

Ch. Wunderly

1956-01-01

349

Gel Electrophoresis on a Budget to Dye for  

ERIC Educational Resources Information Center

|Gel electrophoresis is one of the most important tools used in molecular biology and has facilitated the entire field of genetic engineering by enabling the separation of nucleic acids and proteins. However, commercial electrophoresis kits can cost up to $800 for each setup, which is cost prohibitive for most classroom budgets. This article…

Yu, Julie H.

2010-01-01

350

Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials  

ERIC Educational Resources Information Center

|Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic…

Ens, S.; Olson, A. B.; Dudley, C.; Ross, N. D., III; Siddiqi, A. A.; Umoh, K. M.; Schneegurt, M. A.

2012-01-01

351

Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials  

ERIC Educational Resources Information Center

Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic…

Ens, S.; Olson, A. B.; Dudley, C.; Ross, N. D., III; Siddiqi, A. A.; Umoh, K. M.; Schneegurt, M. A.

2012-01-01

352

Characterization of bovine collagens using capillary electrophoresis — an alternative to slab gel electrophoresis  

Microsoft Academic Search

A capillary electrophoresis method was developed and characterized for analyzing the spectrum of collagen subspecies in collagen preparations. The Bio-Rad CE-SDS protein kit was used for the dynamic sieving separation of collagen subspecies in this CE method (DSCE). The optimized method utilized a 36 cm (or 24 cm)×50 ?m uncoated capillary, electrophoretic injection at 10 kV for 10 s, a

Paul Chang; Son Kuan; Gert Eberlein; David Burke; Richard Jones

2000-01-01

353

Acetate-dependent methylation of two corrinoid proteins in extracts of Methanosarcina barkeri  

SciTech Connect

Corrinoid proteins have been implicated as methyl carriers in methane formation from acetate, yet specific corrinoid proteins methylated by acetate-derived intermediates have not been identified. In the presence of ATP, H{sub 2}, and bromoethanesulfonic acid, label from {sup 3}H- or 2-{sup 14}C-labeled acetate was incorporated into the protein fraction of cell extracts of Methanosarcina barkeri. Incorporated label was susceptible to photolysis, yielding labeled methane as the anaerobic photolysis product. size exclusion high-pressure liquid chromatography (HPLC) demonstrated the presence of at least three labeled proteins with native molecular sizes of 480, 200, and 29 kDa, while electrophoresis indicated that four major labeled proteins were present. Dual-label experiments demonstrated that these four proteins were methylated rather than acetylated. Two of the proteins (480 and 29 kDa) contained the majority of radiolabel and were stably methylated. After labeling with (2-{sup 14}C)acetate, the stable {sup 14}CH{sub 3}-proteins were partially purified, and {sup 14}CH{sub 3}-cofactors were isolated from each protein. UV-visible spectroscopy and HPLC demonstrated these to be methylated corrinoids. When the protein. UV-visible spectroscopy and HPLC demonstrated these to be methylated corrinoids. When the 480-kDa corrinoid protein was purified to 70% homogeneity, the preparation was found to have subunits of 40 and 30 kDa. The 480-kDa protein but not the 29-kDa protein was methylated during in vitro methanogenesis from acetate and demethylated as methanogenesis ceased, consistent with the involvement of this protein in methane formation.

Xianjun Cao; Krzycki, J.A. (Ohio State Univ., Columbus, OH (United States))

1991-09-01

354

Determination of the diol content of chromatographic supports by capillary electrophoresis.  

PubMed

A capillary electrophoresis (CE) method was developed for determining the diol content of supports used in high-performance affinity or size exclusion chromatography. This method involved oxidizing the diol-bonded support with periodate, followed by the use of CE to separate and quantitate the iodate produced by this reaction. Both the oxidation and separation conditions were considered in optimizing this assay. The final method was performed by reacting a known amount of support with a 20-fold excess of periodate in pH 4.0, 0.5 M acetate buffer, with pyromellitic acid being used as an internal standard. After allowing 5-10 min for oxidation, the mixture was filtered and the filtrate was injected onto a 57 cm x 50 microns I.D. fused-silica capillary operated at 25 kV and containing pH 4.0, 0.5 M acetate as the running buffer. The total separation time was 5 min per run and gave a detection limit of 0.1 mM iodate (or 0.1 mumol diol groups) for a 6-nl injection of a 1-ml reaction mixture. By varying the amount the support that was assayed, this method could be used with either porous or non-porous supports. This technique showed good correlation with an iodometric titration but required much less sample and time to perform. PMID:9042737

Chattopadhyay, A; Hage, D S

1997-01-17

355

Nonaqueous capillary electrophoresis conditions for the simultaneous separation of eight alpha-adrenergic blocking agents.  

PubMed

The analysis is described for the first time for separating eight alpha-adrenergic blocking agents (oxymetazoline, 5-methylurapidil, prazosin, phentolamine, RS-17053, methoxamine, yohimbine, and BMY7378) by capillary electrophoresis (CE) with UV detection. Optimum separation of the analytes was obtained on a 50 cm?×?75 ?m i.d. capillary using a buffer containing 20% acetonitrile, 60 mM ammonium acetate, and 1.0% glacial acetic in methanol medium, with applied voltage and capillary temperature of 23 kV and 25 °C, respectively. The relative standard deviations of the migration times and the peak areas of the eight analytes were in the ranges of 0.12-1.29% and 1.02-2.53%, respectively. Detection limits of oxymetazoline, 5-methylurapidil, prazosin, phentolamine, RS-17053, methoxamine, yohimbine, and BMY7378 were 0.5-1.0 ?g mL(-1). In the tested concentration range, good linear relationships (correlation coefficients >98%) between peak areas and concentrations of the analytes were observed. This method has been successfully applied for determination of prazosin and phentolamine with recoveries of 97.30% and 98.12%, respectively. The proposed method was successfully applied for the rapid CE determination of the frequently applied alpha-adrenergic blocking compounds phentolamine and prazosin in general pharmaceutical preparation. PMID:20623269

Chen, Qinhua; Li, Peng; Yang, Handong; Li, Bing; Zhu, Jun; Peng, Lin

2010-07-11

356

Investigating Membranes  

NSDL National Science Digital Library

While not organic in nature, quick-"growing" artificial membranes can be a profound visual aid when teaching students about cellular processes and the chemical nature of membranes. Students are often intrigued when they see biological and chemical concept

Mccallister, Gary; Zrelak, Yoshi

2009-09-01

357

Coupling supported lipid bilayer electrophoresis with matrix-assisted laser desorption/ionization-mass spectrometry imaging.  

PubMed

Herein, we describe a new analytical platform utilizing advances in heterogeneous supported lipid bilayer (SLB) electrophoresis and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging. This platform allowed for the separation and visualization of both charged and neutral lipid membrane components without the need for extrinsic labels. A heterogeneous SLB was created using vesicles containing monosialoganglioside GM1, disialoganglioside GD1b, POPC, as well as the ortho and para isomers of Texas Red-DHPE. These components were then separated electrophoretically into five resolved bands. This represents the most complex separation by SLB electrophoresis performed to date. The SLB samples were flash frozen in liquid ethane and dried under vacuum before imaging with MALDI-MS. Fluorescence microscopy was employed to confirm the position of the Texas Red labeled lipids, which agreed well with the MALDI-MS imaging results. These results clearly demonstrate this platform's ability to isolate and identify nonlabeled membrane components within an SLB. PMID:23731179

Pace, Hudson P; Sherrod, Stacy D; Monson, Christopher F; Russell, David H; Cremer, Paul S

2013-06-03

358

Clostridium thermosaccharolyticum strain deficient in acetate production.  

PubMed Central

A mutant of Clostridium thermosaccharolyticum that is blocked in acetate production was isolated after treatment with nitrosoguanidine and selection for fluoroacetate resistance. The mutant produced more ethanol than the parent strain did.

Rothstein, D M

1986-01-01

359

Fragrance material review on 3-phenylpropyl acetate.  

PubMed

A toxicologic and dermatologic review of 3-phenylpropyl acetate when used as a fragrance ingredient is presented. 3-Phenylpropyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 3-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, skin sensitization, and toxicokinetics data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al., 2012 for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414651

McGinty, D; Letizia, C S; Api, A M

2012-03-04

360

Fragrance material review on anisyl acetate.  

PubMed

A toxicologic and dermatologic review of anisyl acetate when used as a fragrance ingredient is presented. Anisyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for anisyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, elicitation, and phototoxicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al., 2012 for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414654

McGinty, D; Letizia, C S; Api, A M

2012-03-03

361

Fragrance material review on 4-methylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of 4-methylbenzyl acetate when used as a fragrance ingredient is presented. 4-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 4-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, and elicitation data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414643

McGinty, D; Letizia, C S; Api, A M

2012-03-05

362

Acetate Causes Alcohol Hangover Headache in Rats  

PubMed Central

Background The mechanism of veisalgia cephalgia or hangover headache is unknown. Despite a lack of mechanistic studies, there are a number of theories positing congeners, dehydration, or the ethanol metabolite acetaldehyde as causes of hangover headache. Methods We used a chronic headache model to examine how pure ethanol produces increased sensitivity for nociceptive behaviors in normally hydrated rats. Results Ethanol initially decreased sensitivity to mechanical stimuli on the face (analgesia), followed 4 to 6 hours later by inflammatory pain. Inhibiting alcohol dehydrogenase extended the analgesia whereas inhibiting aldehyde dehydrogenase decreased analgesia. Neither treatment had nociceptive effects. Direct administration of acetate increased nociceptive behaviors suggesting that acetate, not acetaldehyde, accumulation results in hangover-like hypersensitivity in our model. Since adenosine accumulation is a result of acetate formation, we administered an adenosine antagonist that blocked hypersensitivity. Discussion Our study shows that acetate contributes to hangover headache. These findings provide insight into the mechanism of hangover headache and the mechanism of headache induction.

Maxwell, Christina R.; Spangenberg, Rebecca Jay; Hoek, Jan B.; Silberstein, Stephen D.; Oshinsky, Michael L.

2010-01-01

363

Factors Affecting Acetate Degradation in Anaerobic Digesters.  

National Technical Information Service (NTIS)

Acetate is the major source of methane produced in anaerobic digestion, accounting for about two thirds of all the methane produced. The major methanogenic bacteria responsible for this reaction are /ital Methanosarcina barkeri/ and /ital Methanosarcina m...

R. A. Mah D. R. Boone

1988-01-01

364

A biologically inspired hydrophobic membrane for application in pervaporation.  

PubMed

An artificial polydimethylsiloxane/polyphenylsulfone (PDMS/PPSU) membrane, which emulates the hydrophobic behavior of natural membranes, was synthesized. Hydrophobicity was achieved by coating the membrane surface sublayer using conventional silicon material, which imitates the character of epicuticular wax (EW) of Prunus laurocerasus L. leaves. It was then applied as a separation medium in pervaporation (PV) of diluted mixtures of ethyl acetate and aroma compounds. The membrane's biomimetic characteristics were evaluated using surface morphology analyses, that is, Fourier transform infrared (FTIR), water contact angle measurements, and SEM imaging. A comparison of properties of the membranes synthesized in this work against selected hydrophobic plant leaves indicated a good agreement. PV using these biologically inspired artificial membranes demonstrated preference for the permeation of ethyl acetate. Besides intrinsic characteristics, it was also observed that the chemical potential is highly influential in activating sorption, diffusion, and desorption of a specific compound. PMID:23323794

Jullok, Nora; Martínez, Rodrigo; Wouters, Christine; Luis, Patricia; Sanz, María Teresa; Van der Bruggen, Bart

2013-01-25

365

Dioxouranium (VI) complexes with cellulose acetate  

Microsoft Academic Search

Dioxouranium [UO2(VI)] complexes with three degrees of substitution of cellulose acetate, prepared from viscose pulp (DS = 2.2, 2.45 and 2.86), have been synthesis and characterized. Degree of substitution (DS) is defined as the average number of CH groups substituted on each anhydrocellulose repeat unit. Probable structures of the cellulose acetate complexes were inferred from the elemental analysis data, conductance

Altaf H. Basta; Wafaa M. Hosny

1998-01-01

366

Minimizing acetate formation in E. coli fermentations  

Microsoft Academic Search

Escherichia coli remains the best-established production organism in industrial biotechnology. However, when aerobic fermentation runs at\\u000a high growth rates, considerable amounts of acetate are accumulated as by-product. This by-product has negative effects on\\u000a growth and protein production. Over the last 20 years, substantial research efforts have been expended on reducing acetate\\u000a accumulation during aerobic growth of E. coli on glucose. From

Marjan De Mey; Sofie De Maeseneire; Wim Soetaert; Erick Vandamme

2007-01-01

367

Pressure-assisted capillary electrophoresis mass spectrometry using combination of polarity reversion and electroosmotic flow for metabolomics anion analysis.  

PubMed

We have developed a method based on capillary electrophoresis (CE) coupled to mass spectrometry (MS) that is a powerful tool for metabolome analysis. In this paper, a simple method for the simultaneous analysis of anionic metabolites such as sugar phosphates, organic acids, nucleotides and CoA compounds based on pressure-assisted capillary electrophoresis coupled to electrospray ionization mass spectrometry (PACE/ESI-MS) is described. The feature of this method is that CE polarity, where the inlet of the capillary is at the anode and the outlet at the cathode, is inverted from conventional CE analysis for anions. Moreover, an ordinary fused silica capillary was chosen instead of a specific cationic polymer-coated capillary (SMILE (+) capillary). A robust and inexpensive analytical method was established from the above-mentioned CE polarity and noncoated fused silica capillary. A trimethylamine acetate electrolyte, pH 10.0, provides a high resolution between isomers. Electrolyte flow using an air pump after electrophoresis enables the comprehensive and simultaneous analyses of sugar phosphates, organic acids, nucleotides and a CoA compound that to date have been impossible to analyze. Our method can be used as a de facto standard for metabolome analysis. PMID:16781469

Harada, Kazuo; Fukusaki, Eiichiro; Kobayashi, Akio

2006-05-01

368

Delignification of Bagasse with Acetic Acid and Ozone. Part 1. Acetic Acid Pulping  

Microsoft Academic Search

Two-stage delignification of sugarcane bagasse with acetic acid and ozone was investigated. The better pulp was obtained pulping bagasse in aqueous solution of acetic acid (80% volume) at 145°C during 60 min. The liquor\\/bagasse ratio (L\\/B) was 10:1 and the kappa number was 44; it fell to 10 in the ozone stage due to selectivity of acetic acid medium. Pulp

H. Contreras Q; Z. A. Nagieb; R. Sanjuán D

1997-01-01

369

Characterization of the Acetate Binding Pocket in the Methanosarcina thermophila Acetate Kinase  

Microsoft Academic Search

Acetate kinase catalyzes the reversible magnesium-dependent synthesis of acetyl phosphate by transfer of the ATP -phosphoryl group to acetate. Inspection of the crystal structure of the Methanosarcina thermophila en- zyme containing only ADP revealed a solvent-accessible hydrophobic pocket formed by residues Val93, Leu122, Phe179, and Pro232 in the active site cleft, which identified a potential acetate binding site. The hypothesis

Cheryl Ingram-Smith; Andrea Gorrell; Sarah H. Lawrence; Prabha Iyer; Kerry Smith; James G. Ferry

2005-01-01

370

Non-aceticlastic methanogenesis from acetate: acetate oxidation by a thermophilic syntrophic coculture  

Microsoft Academic Search

Methanogenesis from acetate by a rod-shaped enrichment culture grown at 60° C was found to require the presence of two organisms rather than a single aceticlastic methanogen. A thermophilic Methanobacterium which grew on H2\\/CO2 or formate was isolated from the enrichment. Lawns of this methanogen were used to co-isolate an “acetate oxidizer” in roll tubes containing acetate agar. The rod-shaped

Stephen H. Zinder; Markus Koch

1984-01-01

371

Effects of chronic and acute lead treatments on the biophysical properties of erythrocyte membranes, and a comparison with model membranes?  

PubMed Central

Rat erythrocytes, or erythrocyte membrane ghosts, have been subjected to either chronic (drinking water containing 15?mM lead acetate for 3?months) or acute (10?9–10?2?M lead acetate for 1?h) Pb2+ treatments and subsequent changes in membrane properties have been measured. Pb2+ concentration in chronically treated rat plasma was 1.8??M, which is one order of magnitude above normal values. Membrane permeability, or hemolysis, was increased in both cases. A comparative study using liposomes, in the form of large unilamellar vesicles, also indicated an increase in membrane permeability. Membrane microviscosity, or acyl chain molecular order, measured as DPH fluorescence polarization, showed an increased order in the acute treatments, at least below 700??M Pb2+, and a similar increase in chronically treated rats. The correlation between acute and chronic treatments, and between cell and model membranes, suggests that the present observations may be relevant in the pathogenesis of lead intoxication in humans.

Ahyayauch, Hasna; Sansar, Wafae; Rendon-Ramirez, Adela; Goni, Felix M.; Bennouna, Mohammed; Gamrani, Halima

2013-01-01

372

Volatile kinetic capillary electrophoresis for studies of protein-small molecule interactions.  

PubMed

Kinetic capillary electrophoresis (KCE) is a toolset of homogeneous affinity methods for studying kinetics of noncovalent binding. Sensitive KCE measurements are typically done with fluorescence detection and require a fluorescent label on a smaller-sized binding partner. KCE with fluorescence detection is difficult to use for study of protein-small molecule interactions since labeling small molecules is cumbersome and can affect binding. A combination of KCE with mass-spectrometry (KCE-MS) has been recently suggested for label-free studies of protein-small molecule interactions. The major obstacle for studies by KCE-MS is a buffer mismatch between KCE and MS; MS requires volatile buffers while KCE of protein-ligand interactions is always run in near-physiological buffers. Here we asked a simple question: can protein-ligand interactions be studied with KCE in a volatile buffer? We compared three volatile buffers (ammonium acetate, ammonium bicarbonate, and ammonium formate) with a near-physiological buffer (Tris-acetate) for three protein-ligand pairs. The volatile buffers were found not to significantly affect protein-ligand complex stability; moreover, when used as CE run buffers, they facilitated good-quality separation of free ligands from the protein-ligand complexes. The use of volatile buffers instead of Tris-acetate in detection of small molecules by MS improved the detection limit by approximately 2 orders of magnitude. These findings prove the principle of "volatile" KCE, which can be easily coupled with MS to facilitate label-free kinetic studies of protein-small molecule interactions. PMID:22823518

Bao, Jiayin; Krylov, Sergey N

2012-08-01

373

Modeling permeation of volatile organic molecules through reverse osmosis spiral-wound membranes  

Microsoft Academic Search

Reverse osmosis is an interesting process to eliminate organic solutes from distillery condensates before recycling them into the fermentation step. However, organic solutes transport phenomena through reverse osmosis membranes are specific. Rejection and sorption of five compounds were studied on a brackish water membrane. Acetic acid and 2,3-butanediol were not sorbed on the membrane while furfural and 2-phenylethanol presented strong

Camille Sagne; Claire Fargues; Bertrand Broyart; Marie-Laure Lameloise; Martine Decloux

2009-01-01

374

Measurement of permeation of membranes by ethanol and water with integrated optics and Raman spectroscopy  

Microsoft Academic Search

A new method for measuring the permeability of synthetic membranes to water and ethanol has been developed. The technique involves using the membrane as a laser waveguide and making Raman scattering measurements from the guided laser beam. The measurements show that alcohol can be detected at low levels within damp cellulose acetate membranes. The results suggest that further exploration using

J. R. Scherer; G. F. Bailey; D. P. Malladi

1983-01-01

375

Nonaqueous capillary electrophoresis with laser-induced fluorescence detection: a case study of comparison with aqueous media.  

PubMed

A novel method based on separation by nonaqueous capillary electrophoresis (NACE) combined with laser-induced fluorescence (LIF) detection was developed and compared with classic aqueous modes of electrophoresis in terms of resolution of solutes of interest and sensitivity of the fluorescence detection. Catecholamines derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) were chosen as test analytes for their subtle fluorescence properties. In aqueous systems, capillary zone electrophoresis (CZE) was not suitable for the analysis of test analytes due to complete fluorescence quenching of NBD-labeled catecholamines in neat aqueous buffer. The addition of micelles or microemulsion droplets into aqueous running buffer can dramatically improve the fluorescence response, and the enhancement seems to be comparable for micellar electrokinetic chromatography (MEKC) and microemulsion electrokinetic chromatography (MEEKC). As another alternative, NACE separation was advantageous when performing the analysis under the optimum separation condition of 20mM sodium tetraborate, 20mM sodium dodecyl sulfate (SDS), 0.1% (v/v) glacial acetic acid, 20% (v/v) acetonitrile (ACN) in methanol medium after derivatization in ACN/dimethyl sulfoxide (DMSO) (3:2, v/v) mixed aprotic solvents containing 20mM ammonium acetate. Compared with derivatization and separation in aqueous media, NACE-LIF procedure was proved to be superior, providing high sensitivity and short migration time. Under respective optimum conditions, the NACE procedure offered the best fluorescence response with 5-24 folds enhancement for catecholamines compared to aqueous procedures. In addition, the mechanisms of derivatization and separation in nonaqueous media were elucidated in detail. PMID:18328323

Zhou, Lei; Wang, Weiping; Wang, Shumin; Hui, Yang; Luo, Zhi; Hu, Zhide

2008-02-13

376

Protein fouling of surface-modified polymeric microfiltration membranes  

Microsoft Academic Search

The effects of varying morphology and surface chemistry on protein fouling of microfiltration membranes were investigated. In part I of the study, on the effects of varying morphology, results show that 0.2 ?m track-etched polycarbonate (PC) membranes internally foul, with external fouling becoming the dominant means of fouling only at later times. A 0.2 ?m cellulose acetate (CA) membrane showed

Jeffrey Mueller; Robert H. Davis

1996-01-01

377

Acetate Oxidation Is the Dominant Methanogenic Pathway from Acetate in the Absence of Methanosaetaceae†  

PubMed Central

The oxidation of acetate to hydrogen, and the subsequent conversion of hydrogen and carbon dioxide to methane, has been regarded largely as a niche mechanism occurring at high temperatures or under inhibitory conditions. In this study, 13 anaerobic reactors and sediment from a temperate anaerobic lake were surveyed for their dominant methanogenic population by using fluorescent in situ hybridization and for the degree of acetate oxidation relative to aceticlastic conversion by using radiolabeled [2-14C]acetate in batch incubations. When Methanosaetaceae were not present, acetate oxidation was the dominant methanogenic pathway. Aceticlastic conversion was observed only in the presence of Methanosaetaceae.

Karakashev, Dimitar; Batstone, Damien J.; Trably, Eric; Angelidaki, Irini

2006-01-01

378

Oxidation of 3- and 4-carenes with mercuric acetate in acetic acid  

Microsoft Academic Search

1.A study was made of the oxidation of 3-carene with Hg(OAc)2 in acetic acid at 23 and 86°, and with (HgOAc)2 at 90°. The action of both of the oxidizing agents leads to the same acetylative oxidation products: the acetates of p-mentha-1,5-dien-8-ol and p-mentha-1(7),5-dien-8-ol.2.The products of the oxidation of 4-carene with Hg(OAc)2 in acetic acid at 20° contain the acetates

B. A. Arbuzov; V. V. Ratner; Z. G. Isaeva; É. Kh. Kazakova; M. G. Belyaeva

1971-01-01

379

Electrophysiological effects of flecainide acetate on stretched guinea pig left atrial muscle fibers  

Microsoft Academic Search

The electrophysiological effects of flecainide acetate (3×10-6 M) on stretched atrial tissue were investigated using guinea-pig left atrial muscle fibers. Before stretching, the resting membrane potential was not affected by flecainide at 1 Hz, although the overshoot potential (Eov) and the action potential duration at 50% repolarization (APD50) were slightly but significantly decreased by 2±1 mV and 2±1 msec, respectively.

Daisuke Inoue; Takeshi Shirayama; Itsuki Omori; Miho Inoue; Ryuta Sakai; Kazuya Ishibashi; Hiroshi Miyazaki; Yasuhiro Yamahara; Tetsuya Tatsumi; Jun Asayama; Masao Nakagawa

1993-01-01

380

Loading of amphipathic weak acids into liposomes in response to transmembrane calcium acetate gradients  

Microsoft Academic Search

We describe a novel procedure to load amphipathic weak acid molecules into preformed liposomes. Differences in calcium acetate concentrations across the liposomal membrane induce an increase of the internal pH. This pH imbalance serves as an efficient driving force to load and accumulate weak acids (5(6)-carboxyfluorescein and nalidixic acid) inside the lipid vesicles. The mechanism of loading and the relevance

Stéphane Clerc; Yechezkel Barenholz

1995-01-01

381

Removal of bisphenol A (BPA) from water by various nanofiltration (NF) and reverse osmosis (RO) membranes.  

PubMed

The removal of an endocrine disrupting compound, bisphenol A (BPA), from model solutions by selected nanofiltration (NF) and reverse osmosis (RO) membranes was studied. The commercially available membranes NF 90, NF 270, XLE BWRO, BW 30 (Dow FilmTech), CE BWRO and AD SWRO (GE Osmonics) were used to compare their performances for BPA removal. The water permeability coefficients, rejection of BPA and permeate flux values were calculated for all membranes used. No significant changes in their BPA removal were observed for all tight polyamide based NF and RO membranes tested except for loose NF 270 membrane. The polyamide based membranes exhibited much better performance than cellulose acetate membrane for BPA removal. Almost a complete rejection (?98%) for BPA was obtained with three polyamide based RO membranes (BW 30, XLE BWRO and AD SWRO). But cellulose acetate based CE BWRO membrane offered a low and variable (10-40%) rejection for BPA. PMID:23731784

Yüksel, Suna; Kabay, Nalan; Yüksel, Mithat

2013-05-20

382

Robotics in biomedical chromatography and electrophoresis.  

PubMed

The ideal laboratory robot can be viewed as "an indefatigable assistant capable of working continuously for 24 h a day with constant efficiency". The development of a system approaching that promise requires considerable skill and time commitment, a thorough understanding of the capabilities and limitations of the robot and its specialized modules and an intimate knowledge of the functions to be automated. The robot need not emulate every manual step. Effective substitutes for difficult steps must be devised. The future of laboratory robots depends not only on technological advances in other fields, but also on the skill and creativity of chromatographers and other scientists. The robot has been applied to automate numerous biomedical chromatography and electrophoresis methods. The quality of its data can approach, and in some cases exceed, that of manual methods. Maintaining high data quality during continuous operation requires frequent maintenance and validation. Well designed robotic systems can yield substantial increase in the laboratory productivity without a corresponding increase in manpower. They can free skilled personnel from mundane tasks and can enhance the safety of the laboratory environment. The integration of robotics, chromatography systems and laboratory information management systems permits full automation and affords opportunities for unattended method development and for future incorporation of artificial intelligence techniques and the evolution of expert systems. Finally, humanoid attributes aside, robotic utilization in the laboratory should not be an end in itself. The robot is a useful tool that should be utilized only when it is prudent and cost-effective to do so. PMID:2671006

Fouda, H G

1989-08-11

383

Microfab-less Microfluidic Capillary Electrophoresis Devices.  

PubMed

Compared to conventional bench-top instruments, microfluidic devices possess advantageous characteristics including great portability potential, reduced analysis time (minutes), and relatively inexpensive production, putting them on the forefront of modern analytical chemistry. Fabrication of these devices, however, often involves polymeric materials with less-than-ideal surface properties, specific instrumentation, and cumbersome fabrication procedures. In order to overcome such drawbacks, a new hybrid platform is proposed. The platform is centered on the use of 5 interconnecting microfluidic components that serve as the injector or reservoirs. These plastic units are interconnected using standard capillary tubing, enabling in-channel detection by a wide variety of standard techniques, including capacitively-coupled contactless conductivity detection (C(4)D). Due to the minimum impact on the separation efficiency, the plastic microfluidic components used for the experiments discussed herein were fabricated using an inexpensive engraving tool and standard Plexiglas. The presented approach (named 5(2)-platform) offers a previously unseen versatility: enabling the assembly of the platform within minutes using capillary tubing that differs in length, diameter, or material. The advantages of the proposed design are demonstrated by performing the analysis of inorganic cations by capillary electrophoresis on soil samples from the Atacama Desert. PMID:23585815

Segato, Thiago P; Bhakta, Samir A; Gordon, Matthew; Carrilho, Emanuel; Willis, Peter A; Jiao, Hong; Garcia, Carlos D

2013-04-01

384

Capillary electrophoresis for meat species differentiation.  

PubMed

A sodium dodecyl sulfate (SDS) polymer-filled capillary gel electrophoresis (CE-SDS) method was developed and optimized for the determination of meat proteins for species differentiation. Sarcoplasmic proteins were extracted with cold bidistilled deionized water and myofibrillar proteins with 0.6 M NaCl/0.01 M phosphate buffer with 0.5% polyphosphates at pH 6 from raw beef, turkey, and pork muscles. Samples were prepared for CE-SDS and the experimental conditions, including sample size, applied voltage, reducing agent, and its concentration, were obtained after a univariate optimization process. Separation of the sarcoplasmic and myofibrillar meat proteins was achieved with the optimized conditions of the CE-SDS method developed. The coefficient of variation was less than 1.15% in migration time for all peaks and less than 8.5% in area percentage. The CE-SDS sarcoplasmic protein profiles that resulted were specific for each species both qualitatively and quantitatively and could be employed for differentiation and identification purposes. This CE-SDS method can be used by regulatory agencies for rapid analysis of meat proteins to identify meat species. Automation, fast separation, and on-line data analysis are major advantages of this technique. PMID:9627836

Cota-Rivas, M; Vallejo-Cordoba, B V

385

Capillary electrophoresis analysis of orange juice pectinesterases.  

PubMed

Pectinesterase (PE) was extracted from orange juice and pulp with 1 M NaCl, desalted, and separated using capillary electrophoresis (CE) gel procedures (CE-SDS-CGE) and isoelectric focusing (CE-IEF). PE resolved as a single peak using noncoated fused silica columns with CE-SDS-CGE. CE-IEF separation of PE required acryloylaminoethoxyethanol-coated columns, which had limited stability. Thermal stability of PE extracts before and after heating at 75 degrees C for 30 min and at 95 degrees C for 5 min established heat labile and heat stabile fractions with identical PE migration times by CE-SDS-CGE or CE-IEF. Peak magnitude decreased to a constant value as heating time increased at 75 degrees C. Regression analysis of CE-SDS-CGE peak migration times of molecular weight (MW) standards estimated both heat labile and heat stable PE at MW approximately 36 900. Traditional SDS-PAGE gel separation of MW standards and active PE isolated by IEF allowed estimation of MW approximately 36 000. CE-SDS-CGE allowed presumptive, but not quantitative, detection of active PE in fresh juice. PMID:11262039

Braddock, R J; Bryan, C R; Burns, J K

2001-02-01

386

Determination of acarbose by capillary zone electrophoresis.  

PubMed

Acarbose (Glucobay, Bayer AG) acts as a potent alpha-glucosidase-inhibitor, which delays the intestinal starch digestion resulting in a reduction of postprandial blood glucose and insulin levels. Acarbose is a pseudo-tetrasaccharide, with two D-glucose units linked via an alpha 1-->4 glycosidic bond to acarviosin, which is a N-glycoside composed of an unsaturated cyclitol and 4-amino-4,6-dideoxy-alpha-D-glucopyranose. Several methods for the determination of acarbose by capillary electrophoresis can be found in literature. They are based either on the derivatisation with 7-aminonaphthalene-1,3-disulfonic acid (ANDS) or on the detection of the unsaturated cyclitol at wavelengths below 200 nm. The aim of our work was the determination of acarbose making use of a previously developed method based on reductive amination with S-phenylethylamine. The aminoalditols generated in the reaction formed differently charged borate-complexes depending on the configuration of the sugar. After successful method optimisation we were able to separate two potential impurities of acarbose, D-maltose und D-glucose. For the quantitation of acarbose in Glucobay tablets an additional borate-buffer system was established, reducing the total time of analysis to less than 10 min. PMID:23923633

Lachmann, B; Noe, C R

2013-07-01

387

[Separation of sitafloxacin epimers by capillary electrophoresis].  

PubMed

Sitafloxacin epimers were separated by capillary zone electrophoresis using gamma-cyclodextrin (gamma-CD) and D-phenylalanine (D-Phe) as chiral selector. The effects of the concentrations of gamma-CD, D-Phe, Cu2+ and pH of buffer were investigated. An uncoated fused-silica capillary of 50 microm i.d. and 60 cm (effective length 52.5 cm) was used. The capillary temperature was maintained at 25 degrees C. Samples were injected under a pressure of 7 kPa for 5 s and separated at 15 kV. A baseline separation of sitafloxacin epimers was achieved with a background electrolyte of 10 mmol/L KH2PO4-K2HPO4(pH 4.5), 10 mmol/L CuSO4, 20 mmol/L gamma-CD and 10 mmol/L D-Phe. The linear range for sitafloxacin was 32 -400 mg/L (0.996). The relative standard deviations (RSDs) of migration time and peak area were less than 1.9% and 3.8% respectively. This method can be applied in qualitative and quantitative analysis for sitafloxacin epimers. PMID:17165551

Yuan, Pei; Lin, Lei; Fan, Qi; Zeng, Linggao

2006-09-01

388

Serum protein electrophoresis in 147 dogs.  

PubMed

Reference intervals for serum protein electrophoresis (SPE) were created from a group of 75 clinically healthy dogs and compared with SPE results obtained from clinical cases presented to the University of Bristol over an eight-and-a-half-year period. A total of 147 dogs, in which SPE had been performed, had complete case records available and thus met the inclusion criteria. Signalment and final diagnoses taken from the case records and SPE results were divided into normal and abnormal based on the newly established reference intervals. Cases were grouped according to the SPE protein fraction abnormalities and diagnosis using the DAMNITV classification system. Of the 147 cases, 140 (95.2 per cent) had abnormal SPE results. The most common protein fraction abnormality was decreased albumin (59.3 per cent) followed by a polyclonal increase in ? globulins (38.6 per cent). Decreased ?-1 globulins and increased ?-2 globulins were documented in 36.4 and 30.0 per cent of cases, respectively. The most common DAMNITV classification associated with abnormal SPE results was infectious/inflammatory disease, which was diagnosed in 79 of 140 cases (56.4 per cent). Monoclonal gammopathies were noted in eight dogs (5.7 per cent), and underlying lymphoproliferative disease was present in all cases where a diagnosis was achieved, including multiple myeloma (four dogs), splenic plasmacytoma (one dog), hepatic plasmacytoma (one dog) and lymphoma (one dog). PMID:21493443

Tappin, S W; Taylor, S S; Tasker, S; Dodkin, S J; Papasouliotis, K; Murphy, K F

2011-04-11

389

Formamide as solvent for capillary zone electrophoresis.  

PubMed

A comprehensive investigation of a number of aspects when using formamide as background electrolyte solvent in capillary zone electrophoresis was presented. It included (i) the change of the ion mobility with ionic strength, (ii) the influence of the ionic strength on diffusion coefficients, and (iii) on the separation efficiency expressed by the maximum reachable plate numbers (when only longitudinal diffusion contributed to zone broadening), (iv) the effect of the solvent on pKa values (taken from the literature) of neutral and cation acids, (v) the establishment of the a pH scale in formamide by dissolving acids with known pKa values and their salts at defined proportion (thus circumventing the problem of calibrating the pH meter), (vi) the agreement between the experimentally derived and the theoretical dependence of the effective mobility on pH, (vii) the uptake of water of this hygroscopic solvent from the humidity of the environment and its consequence to the ion mobilities, pKa values, and the chemical stability of the solvent (e.g., hydrolysis), and finally (viii) the use of conductivity and indirect UV absorption to enable detection of analytes below the optical cutoff of formamide. PMID:15349934

Porras, Simo P; Kenndler, Ernst

2004-09-01

390

Nitromethane as solvent in capillary electrophoresis.  

PubMed

Nitromethane has several properties that make it an interesting solvent for capillary electrophoresis especially for lipophilic analytes that are not sufficiently soluble in water: freezing and boiling points are suitable for laboratory conditions, low viscosity leads to favourable electrophoretic mobilities, or an intermediate dielectric constant enables dissolution of electrolytes. In the present work we investigate the change of electrophoretically relevant analyte properties - mobilities and pKa values - in nitromethane in dependence on the most important experimental conditions determined by the background electrolyte: the ionic strength, I, and the pH. It was found that the mobility decreases with increasing ionic strength (by, e.g. up to 30% from I = 0 to 50 mmol/L) according to theory. An appropriate pH scale is established by the aid of applying different concentration ratios of a buffer acid with known pKa and its conjugate base. The mobility of the anionic analytes (from weak neutral acids) depends on the pH with the typical sigmoidal curve in accordance with theory. The pKa of neutral acids derived from these curves is shifted by as much as 14 pK units in nitromethane compared to water. Both findings confirm the agreement of the electrophoretic behaviour of the analytes with theories of electrolyte solutions. Separation of several neutral analytes was demonstrated upon formation of charged complexes due to heteroconjugation with chloride as ionic constituent of the background electrolyte. PMID:16038311

Subirats, Xavier; Porras, Simo P; Rosés, Martí; Kenndler, Ernst

2005-06-24

391

Differentiation of Enantiomers by Capillary Electrophoresis.  

PubMed

Capillary electrophoresis (CE) has matured to one of the major liquid phase enantiodifferentiation techniques since the first report in 1985. This can be primarily attributed to the flexibility as well as the various modes available including electrokinetic chromatography (EKC), micellar electrokinetic chromatography (MEKC), and microemulsion electrokinetic chromatography (MEEKC). In contrast to chromatographic techniques, the chiral selector is mobile in the background electrolyte. Furthermore, a large variety of chiral selectors are available that can be easily combined in the same separation system. In addition, the migration order of the enantiomers can be adjusted by a number of approaches. In CE enantiodifferentiations the separation principle is comparable to chromatography while the principle of the movement of the analytes in the capillary is based on electrophoretic phenomena. The present chapter will focus on mechanistic aspects of CE enantioseparations including enantiomer migration order and the current understanding of selector-selectand structures. Selected examples of the basic enantioseparation modes EKC, MEKC, and MEEKC will be discussed. PMID:23666080

Scriba, Gerhard K E

2013-05-11

392

Fused quartz substrates for microchip electrophoresis  

SciTech Connect

A fused quartz microchip is fabricated to perform capillary electrophoresis of metal ions complexed with 8-hydroxyquinoline-5-sulfonic acid (HQS). The channel manifold on the quartz substrate is fabricated using standard photolithographic, etching, and deposition techniques. By incorporating a direct bonding technique during the fabrication of the microchip, the substrate and cover plate can be fused together below the melting temperature for fused quartz. To enhance the resolution for the separation, the electroosmotic flow is minimized by covalently bonding polyacrylamide to the channel walls. A separation length of 16.5 mm and separation field strength of 870 V/cm enable separations to be performed in {<=}15 s. By increasing the concentration of HQS from 5 mM to 20 mM, the separation efficiency improves by approximately 3 times. The low background signal from the fused quartz substrate results in mass detection limits of 85, 61, and 134 amol and concentration detection limits of 46, 57, and 30 ppb for Zn, Cd, and Al, respectively. 30 refs., 6 figs., 2 tabs.

Jacobson, S.C.; Moore, A.W.; Ramsey, J.M. [Oak Ridge National Lab., TN (United States)

1995-07-01

393

Characterization of carboxylated nanolatexes by capillary electrophoresis.  

PubMed

Poly(styrene-co-acrylic acid) (St/AA) and poly(styrene-co-methacrylic acid) (St/MA) nanolatexes with different acid contents were prepared by emulsion copolymerization and were analyzed by capillary electrophoresis (CE) and by laser doppler velocimetry (LDV). Due to the intrinsic differences in the methodologies, CE (separative technique) and LDV (zetametry, nonseparative technique) lead to very different electrophoretic mobility distributions. Beyond these differences, the variation of the electrophoretic mobility is a complex and nonlinear function of the hydrodynamic radius, the ionic strength, and the zeta potential. To gain better insight on the influence of the ionic strength and the acid content on the electrophoretic behavior of the nanolatexes, the electrophoretic mobility data were changed into surface charge densities using the O'Brien, White, and Ohshima modeling. This approach leads to the conclusion that the surface charge density is mainly controlled at high ionic strength (?50 mM) by the adsorption of anionic surfactants coming from the sample. On the contrary, at low ionic strength, and/or in the presence of neutral surfactant in the electrolyte, the acid content was the main parameter controlling the surface charge density of the nanolatexes. PMID:21344892

Oukacine, Farid; Morel, Aurélie; Cottet, Hervé

2011-02-23

394

Genomic Expression Program Involving the Haa1p-Regulon in Saccharomyces cerevisiae Response to Acetic Acid  

PubMed Central

Abstract The alterations occurring in yeast genomic expression during early response to acetic acid and the involvement of the transcription factor Haa1p in this transcriptional reprogramming are described in this study. Haa1p was found to regulate, directly or indirectly, the transcription of approximately 80% of the acetic acid-activated genes, suggesting that Haa1p is the main player in the control of yeast response to this weak acid. The genes identified in this work as being activated in response to acetic acid in a Haa1p-dependent manner include protein kinases, multidrug resistance transporters, proteins involved in lipid metabolism, in nucleic acid processing, and proteins of unknown function. Among these genes, the expression of SAP30 and HRK1 provided the strongest protective effect toward acetic acid. SAP30 encode a subunit of a histone deacetylase complex and HRK1 encode a protein kinase belonging to a family of protein kinases dedicated to the regulation of plasma membrane transporters activity. The deletion of the HRK1 gene was found to lead to the increase of the accumulation of labeled acetic acid into acid-stressed yeast cells, suggesting that the role of both HAA1 and HRK1 in providing protection against acetic acid is, at least partially, related with their involvement in the reduction of intracellular acetate concentration.

Becker, Jorg D.; Sa-Correia, Isabel

2010-01-01

395

Nanofiltration of rhodium tris(triphenylphosphine) catalyst in ethyl acetate solution  

NASA Astrophysics Data System (ADS)

Solvent resistant nanofiltration (SRNF) using polymer membranes has recently received enhanced attention due to the search for cleaner and more energy-efficient technologies. The large size of the rhodium tris(triphenylphosphine) [HRh(CO)(PPh3)3] catalyst (>400 Da) - relative to other components of the hydroformylation reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (DuraMem{trade mark, serif} 200 and DuraMem{trade mark, serif} 500) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. Good HRh(CO)(PPh3)3 rejection (>0.95) and solvent fluxes of 9.9 L/m2.h1 at 2.0 MPa were obtained in the catalyst-ethyl acetate-DuraMem 500 system. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted on the catalyst-ethyl acetate-membrane systems. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting solvent flux.

Shaharun, Maizatul S.; Mustafa, Ahmad K.; Taha, Mohd F.

2012-09-01

396

A systematic study of field inversion gel electrophoresis.  

PubMed Central

The mobilities of oligomers of phage lambda DNA and of yeast chromosomes in agarose gels during field inversion gel electrophoresis (FIGE) were measured at different pulse times and electric fields. Also the ratios between forward and backward pulse times and/or field gradients were varied. The problem of 'band inversion' during FIGE, leading to an ambiguity in the mobility of large DNA fragments, was solved by using two dimensional gel electrophoresis with different parameters in the first and second dimension. The results are compared with those obtained with other pulsed electrophoresis systems and with a theoretical model. Images

Heller, C; Pohl, F M

1989-01-01

397

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

398

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

399

Friction and wear behaviour of acetal and nylon gears  

Microsoft Academic Search

The current paper will present an extensive investigation of polymer gear (acetal and nylon) friction and wear behaviour. First, a unique test method for polymer gear wear will be described in brief and later used in the extensive investigation of acetal and nylon gear wear. Initial tests were performed using acetal pinions with acetal gears, and nylon pinions with nylon

K. Mao; W. Li; C. J. Hooke; D. Walton

2009-01-01

400

Comparative plasma membrane-associated proteomics of immortalized human hepatocytes  

Microsoft Academic Search

This work was initiated with the purpose of purifying and identifying differentially expressed plasma membrane-associated\\u000a proteins between human liver cancer cell line HepG2 and normal liver cell line L02. The combined strategy of sucrose density\\u000a gradient centrifugation and subsequent phase partition was applied to obtain high-purity proteins of plasma membrane. Two-dimensional\\u000a gel electrophoresis revealed the differential protein profile between the

Lan-Tu Gou; Ai-Ping Tong; Li-Juan Chen; Ming-Hai Tang; Bin Chen; Shu-Fang Liang; Canhua Huang; Yu-Quan Wei

2008-01-01

401

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

402

Outer membrane vesicles as acellular vaccine against pertussis  

Microsoft Academic Search

In this study the development and evaluation of outer membrane vesicles (OMVs) obtained from Bordetella pertussis as vaccines against pertussis disease is described. SDS-PAGE, immunoblot techniques and gel electrophoresis associated to tandem mass spectrometry were used to describe the composition of the OMVs obtained from B. pertussis Tohama CIP 8132 strain. These techniques revealed the presence of the main well-known

Roy Roberts; Griselda Moreno; Daniela Bottero; Maria Emilia Gaillard; Matías Fingermann; Augusto Graieb; Martin Rumbo; Daniela Hozbor

2008-01-01

403

Calcination of calcium acetate and calcium magnesium acetate: effect of the reacting atmosphere  

Microsoft Academic Search

The calcination process of the calcium acetate (CA) and calcium magnesium acetate (CMA) was investigated as a previous step for coal gas desulfurisation during sorbent injection at high temperatures because the excellent results demonstrated by these sorbents as sulfur removal agents both in combustion and gasification processes. As pore structure developed during calcination is one of the most important characteristic

J. Adánez; L. F. de Diego; F. Garc??a-Labiano

1999-01-01

404

Determination of odour detection thresholds for acetic acid and ethyl acetate in ice wine  

Microsoft Academic Search

Collectively acetic acid and ethyl acetate are responsible for ‘volatile acidity’ (VA) in wine. The detection limit or threshold for these compounds is well documented in table wine but not for ice wine. Knowledge of the ice wine thresholds is important for understanding perception limits and setting legal standards, particularly for a product with high intrinsic concentrations. Thresholds were determined

Margaret A. Cliff; Gary J. Pickering

2006-01-01

405

Factors affecting acetate degradation in anaerobic digesters  

SciTech Connect

Acetate is the major source of methane produced in anaerobic digestion, accounting for about two thirds of all the methane produced. The major methanogenic bacteria responsible for this reaction are )ital Methanosarcina barkeri) and )ital Methanosarcina mazei). One strain of each of these bacteria was selected for this study, in which the effect of molecular hydrogen on acetate dissimilation was examined. We examined the effects that hydrogen concentration had on the active growth of aceticlastic (acetate-splitting) cultures. We found that, during steady-state growth, each of these methanogens ()ital M. barkeri) or )ital M. mazei)) could tolerate a wide range of hydrogen concentrations with little change in their rates of acetate degradation. At hydrogen partial pressures as low as 2 Pa and as high as 800 Pa no change was detected in the growth rate or acetate degradation rate of either of these methanogens. However, we also showed that small amounts of hydrogen were produced or consumed by )ital Methanosarcina) in order to bring the hydrogen concentration in their environment to a pressure of 16 to 92 Pa, similar to that found in anaerobic digestors.

Mah, R.A.; Boone, D.R.

1988-01-01

406

Genera and species in acetic acid bacteria.  

PubMed

Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus "Acetomonas" was described in 1954 for strains with polar flagellation and no oxidation of acetate. The proposals of the two generic names were due to confusion, and "Acetomonas" was a junior subjective synonym of Gluconobacter. The genus Acetobacter was in 1984 divided into two subgenera, Acetobacter and Gluconoacetobacter. The latter was elevated to the genus Gluconacetobacter in 1998. In the acetic acid bacteria, ten genera are presently recognized and accommodated to the family Acetobacteraceae, the Alphaproteobacteria: Acetobacteer, Gluconobacter, Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia and Granulibacter. In contrast, the genus Frateuria, strains of which were once named 'pseudacetic acid bacteria', was classified into the Gammaproteobacteria. The genus Gluconacetobacter was phylogenetically divided into two groups: the Gluconacetobacter liquefaciens group and the Gluconacetobacter xylinus group. The two groups were discussed taxonomically. PMID:18199517

Yamada, Yuzo; Yukphan, Pattaraporn

2007-12-05

407

Lithographic properties of novel acetal-derivatized hydroxy styrene polymers  

NASA Astrophysics Data System (ADS)

Lithographic properties of a variety of acetal-derivatized styrene based polymers are reported. The structural modifications in the polymers involve varying the size of the pendent acetal moiety. the lithographic performances of the resists containing structurally modified acetals were found to be superior to the conventional acetals. In the cases where the acidolysis products of the modified acetals are non-volatile alcohols, the post-exposure volatilization, film shrinkage and plasma etch resistance were found to be significantly improved.

Malik, Sanjay; Blakeney, Andrew J.; Ferreira, Lawrence; Maxwell, Brian; Whewell, Allyn; Sarubbi, Thomas R.; Bowden, Murrae J.; van Driessche, Willy; Fujimori, Toru; Tan, Shiro; Aoai, Toshiaki; Uenishi, Kazuya; Kawabe, Yasumasa; Kokubo, Tadayoshi

1999-05-01

408

Investigations of the Inhibitory Effects of Tocopherol (Vitamin E) on Free Radical Deterioration of Cellular Membranes.  

National Technical Information Service (NTIS)

The inhibitory effects are investigated of d,1-alpha-tocopherol and d,1-alpha-tocopheryl acetate on the free radical deterioration of cellular membranes. The level of toxicity of d,1-alpha-tocopherol and d,1-alpha-tocopheryl acetate in mice is determined....

D. Richardson

1975-01-01

409

A microchannel electrophoresis DNA sequencing system  

SciTech Connect

Last year, the Joint Genome Institute was the third leading sequencing group in the world with over 20 million bases of human DNA finished. The goal of the human genome project is to sequence the 3 billion bases of human DNA sequence by 2003. In order to increase the DNA sequencing throughput of the Joint Genome Institute, we have developed a microchannel electrophoresis system. One critical new and unique element of this system is a process for production of 96 and 384 microchannels on bonded glass substrates up to 14 x 58 cm. In order to utilize these instruments for DNA production sequencing, we have been evaluating and implementing software to convert raw electropherograms into called DNA bases with an associated probability of error. Our original intent was to utilize the DNA base calling software known as Plan and Phred developed by the University of Washington. In our tests and evaluations of this software applied to microchannel data, we observed that the electropherograms are of a different statistical and underlying signal structure compared to slab gels. We have modified Plan and Phred to improve base calling performance for the microchannel data. In this paper, we will present 1) the microchannel DNA sequencing system and show the advantages compared to current slab gel and capillary systems. 2) The signal processing modules needed for DNA base calling including correction of multiple wavelength channels, signal averaging, non-uniform sampling, variable DNA mobility, and peak shape and spreading effects. 3) A comparison of the DNA base signatures in the raw data of microchannels vs. slab gels including some simple modeling results. This will be propagated through the base calling software to show the impact on DNA sequencing.

Balch, J W; Bass, M S; Brewer, L R; Copeland, A C; Davidson, J C; Fitch, J P; Kegelmeyer; Kimbrough, J R; L M; Madabhushi, R S; McCready, P M; Nelson, D O; Pastrone, R L; Richardson, P M; Swierkowski, S P; Tarte, L A; Vainer, M; Warth, T E

1999-02-01

410

Octanol-Water Partition Coefficients by Capillary Electrophoresis.  

National Technical Information Service (NTIS)

We have investigated the use of capillary electrophoresis (CE) for the modeling of octanol-water partition coefficients. Reversed-phase liquid chromatography (RPLC) is likely the most used method for estimation of octanol-water partition coefficients, wit...

J. G. Dorsey

1997-01-01

411

TECHNIQUES WITH POTENTIAL FOR HANDLING ENVIRONMENTAL SAMPLES IN CAPILLARY ELECTROPHORESIS  

EPA Science Inventory

An assessment of the methods for handling environmental samples prior to capillary electrophoresis (CE) is presented for both aqueous and solid matrices. Sample handling in environmental analyses is the subject of ongoing research at the Environmental Protection Agency's National...

412

Paper Electrophoresis of Saliva Albumins (Elektroforeza Bibulowa Bialek Sliny).  

National Technical Information Service (NTIS)

The proteins of mixed human saliva were concentrated by prevaporation, separated by electrophoresis and the fractions obtained there were of determined quantitatively. Three different techniques of separation were developed. The best separation was obtain...

T. Szymczyk

1967-01-01

413

CAPILLARY ELECTROPHORESIS FOR THE CHARACTERIZATION OF HUMIC SUBSTANCES  

EPA Science Inventory

The potential of high performance capillary electrophoresis (HPCE), especially in the free solution mode (FSCE), is demonstrated for the analysis/characterization of environmental humic substances (HUS). he very high efficiency of HPCE separations allows the production of electro...

414

Zone Electrophoresis of Human Parotid Saliva in Acrylamide Gel.  

National Technical Information Service (NTIS)

The report concerns an examination of acrylamide gel as another medium for the zone electrophoresis of parotid saliva proteins. Preliminary experiments with acrylamide-gel strips yielded protein patterns in which twenty or more fractions could be visually...

T. S. Meyer B. L. Lamberts

1965-01-01

415

Microchannel DNA Sequencing by End-Labelled Free Solution Electrophoresis  

SciTech Connect

The further development of End-Labeled Free-Solution Electrophoresis will greatly simplify DNA separation and sequencing on microfluidic devices. The development and optimization of drag-tags is critical to the success of this research.

Barron, A.

2005-09-29

416

Megestrol acetate-induced adrenal insufficiency.  

PubMed

Megestrol acetate is a synthetic progestin that has been used since the 1970s for the treatment of advanced cancer and subsequently to treat anorexia, cachexia and weight loss in AIDS patients. It has been shown that high doses or prolonged treatment with this drug may cause Cushing's syndrome, new-onset diabetes and suppression of plasma ACTH and cortisol levels. Megestrol acetate may cause suppression of the pituitary-adrenal axis due to the affinity of this compound for the glucocorticoid receptor. Recognising the glucocorticoid-like activity of megestrol and its effects at the axis level is important for the diagnosis of sub-clinical adrenal insufficiency. We present the case of a 74-year-old woman with infiltrating ductal breast carcinoma refractory to prolonged hormonal treatment with megestrol acetate, presenting with adrenal insufficiency. PMID:18411198

González Villarroel, Paula; Fernández Pérez, Isaura; Páramo, Concepción; Gentil González, Marta; Carnero López, Beatriz; Vázquez Tuñas, M Lidia; Carrasco Alvarez, Juan A

2008-04-01

417

Simple differential detection of Entamoeba histolytica and Entamoeba dispar in fresh stool specimens by sodium acetate-acetic acid-formalin concentration and PCR.  

PubMed

Amoebiasis is caused by two distinct species, a pathogenic form (Entamoeba histolytica) and a nonpathogenic form (Entamoeba dispar), which are morphologically identical. Although the distinction between these two species is of great clinical importance, the methods developed for this purpose either are very time-consuming or involve laborious procedures for isolation of the DNA. We report here a simple PCR method starting with fresh stool specimen that allows for the sensitive and reliable distinction between E. histolytica and E. dispar. After initial concentration by the sodium acetate-acetic acid-formalin (SAF) method and digestion with proteinase K, a 0.88-kb sequence of the multicopy 16S rRNA gene served as a target for PCR amplification. The method starting with unpreserved specimens proved to be very sensitive and was not influenced by the quick exposure to SAF fixative during the initial concentration step. However, storage in SAF fixative prior to testing resulted in a decreased sensitivity within 2 days. The detection limit of the method was as low as one copy of the 16S rRNA gene. No cross-reactivity was observed with other common intestinal protozoa. Mixed infections involving both E. histolytica and E. dispar could easily be detected at a ratio of 1:10,000 by agarose gel electrophoresis or a DNA hybridization immunoassay. PMID:9196177

Troll, H; Marti, H; Weiss, N

1997-07-01

418

Guidelines for reporting the use of gel electrophoresis in proteomics  

Microsoft Academic Search

the MIAPE Gel Electrophoresis (MIAPE-GE) guidelines specify the minimum information that should be provided when reporting the use of n-dimensional gel electrophoresis in a proteomics experiment. Developed through a joint effort between the gel-based analysis working group of the Human Proteome Organisation's Proteomics Standards Initiative (HUPO-PSI; http:\\/\\/www.psidev.info\\/) and the wider proteomics community, they constitute one part of the overall Minimum

Frank Gibson; Leigh Anderson; Gyorgy Babnigg; Mark Baker; Matthias Berth; Pierre-Alain Binz; Andy Borthwick; Phil Cash; Billy W Day; David B Friedman; Donita Garland; Howard B Gutstein; Christine Hoogland; Neil A Jones; Alamgir Khan; Joachim Klose; Angus I Lamond; Peter F Lemkin; Kathryn S Lilley; Jonathan Minden; Nicholas J Morris; Norman W Paton; Michael R Pisano; John E Prime; Thierry Rabilloud; David A Stead; Chris F Taylor; Hans Voshol; Anil Wipat; Andrew R Jones

2009-01-01

419

Microchip-based capillary electrophoresis of human serum proteins  

Microsoft Academic Search

The separation and relative quantitation of human serum proteins is important to the clinical diagnosis of various states of disease. Microchip-based capillary electrophoresis (CE) of human serum proteins offers several advantages over sodium dodecyl sulfate-poly(acrylamide) gel electrophoresis and conventional CE methods, including decreased sample consumption and analysis time and the possibility of on-chip sample manipulation (dilution, labelling, etc.). The microchip

Christa L. Colyer; Shakuntala D. Mangru; D. Jed Harrison

1997-01-01

420

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

421

Phylogenetic reconstruction of South American felids defined by protein electrophoresis  

Microsoft Academic Search

Phylogenetic associations among six closely related South American felid species were defined by changes in protein-encoding gene loci. We analyzed proteins isolated from skin fibroblasts using two-dimensional electrophoresis and allozymes extracted from blood cells. Genotypes were determined for multiple individuals of ocelot, margay, tigrina, Geoffroy's cat, kodkod, and pampas cat at 548 loci resolved by two-dimensional electrophoresis and 44 allozyme

J. Pecon Slattery; W. E. Johnson; D. Goldman; S. J. O'Brien

1994-01-01

422

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

423

Constitutive apical membrane recycling in Aplysia enterocytes.  

PubMed

In Aplysia californica enterocytes, alanine-stimulated Na+ absorption increases both apical membrane exocytosis and fractional capacitance (fCa; a measure of relative apical membrane surface area). These increases are thought to reduce membrane tension during periods of nutrient absorption that cause the enterocytes to swell osmotically. In the absence of alanine, exocytosis and fCa are constant. These findings imply equal rates of constitutive endocytosis and exocytosis and constitutive recycling of the apical plasma membrane. Thus, the purpose of this study was to confirm and determine the relative extent of constitutive apical membrane recycling in Aplysia enterocytes. Biotinylated lectins are commonly used to label plasma membranes and to investigate plasma membrane recycling. Of fourteen biotinylated lectins tested, biotinylated wheat germ agglutinin (bWGA) bound preferentially to the enterocytes apical surface. Therefore, we used bWGA, avidin D (which binds tightly to biotin), and the UV fluorophore 7-amino-4-methylcoumarin-3-acetic acid (AMCA)-conjugated avidin D to assess the extent of constitutive apical membrane recycling. A temperature-dependent (20 vs. 4 degrees C) experimental protocol employed the use of two tissues from each of five snails and resulted in a approximately 60% difference in apical surface fluorescence intensity. Because the extent of membrane recycling is proportional to the difference in surface fluorescence intensity, this difference reveals a relatively high rate of constitutive apical membrane recycling in Aplysia enterocytes. PMID:15673107

Keeton, Robert Aaron; Runge, Steven William; Moran, William Michael

2004-11-01

424

Pulsed-field gel electrophoresis of bacterial chromosomes.  

PubMed

The separation of fragments of DNA by agarose gel electrophoresis is integral to laboratory life. Nevertheless, standard agarose gel electrophoresis cannot resolve fragments bigger than 50 kb. Pulsed-field gel electrophoresis is a technique that has been developed to overcome the limitations of standard agarose gel electrophoresis. Entire linear eukaryotic chromosomes, or large fragments of a chromosome that have been generated by the action of rare-cutting restriction endonucleases, can be separated using this technique. As a result, pulsed-field gel electrophoresis has many applications, from karyotype analysis of microbial genomes, to the analysis of chromosomal strand breaks and their repair intermediates, to the study of DNA replication and the identification of origins of replication. This chapter presents a detailed protocol for the preparation of Escherichia coli chromosomal DNA that has been embedded in agarose plugs, digested with the rare-cutting endonuclease NotI, and separated by contour-clamped homogeneous field electrophoresis. The principles in this protocol can be applied to the separation of all fragments of DNA whose size range is between 40 kb and 1 Mb. PMID:23913293

Mawer, Julia S P; Leach, David R F

2013-01-01

425

Synergism of capillary isotachophoresis and capillary zone electrophoresis.  

PubMed

The combination of capillary isotachophoresis and capillary zone electrophoresis may enhance greatly the performance of analytical capillary electrophoresis with respect to both separation power and the concentration sensitivity. The concentrating effects and the separation power of isotachophoresis allow the analysis of diluted samples and the elimination of interferences due to bulk components. The separation process of zone electrophoresis enables one to resolve the stack of trace analytes and detect the resulting individual zones with high sensitivity. The transition of isotachophoresis into zone electrophoresis plays the key role in the overall performance of this hyphenated technique. This article describes the dynamics of the conversion of isotachophoresis into zone electrophoretic mode and shows that the key role is played by the segments of the leading and terminating zones from the isotachophoretic stage. The magnitude of these segments directly effects the detection time as well as the separation width of the peaks of analytes. It is shown that these effects are also important in the analyses by capillary zone electrophoresis where isotachophoresis is induced by the sample itself. Finally, the paper presents a list of recommended, user-friendly, electrolyte systems which enable one to simply predict the performance of the combination isotachophoresis-zone electrophoresis. PMID:9061479

Krivánková, L; Bocek, P

1997-02-01

426

Removal of inhibitors from lignocellulosic hydrolyzates by vacuum membrane distillation.  

PubMed

In this study, vacuum membrane distillation (VMD) was used to remove two prototypical fermentation inhibitors (acetic acid and furfural) from lignocellulose hydrolyzates. The effect of operating parameters, such as feed temperature and feed velocity, on the removal efficiencies of inhibitors was investigated. Under optimal conditions, more than 98% of furfural could be removed by VMD. However, the removal efficiency of acetic acid was considerably lower. After furfural and acetic acid were selectively removed from hydrolyzates by VMD, ethanol production efficiency increased by 17.8% compared to original hydrolyzates. PMID:23907067

Chen, Jingwen; Zhang, Yaqin; Wang, Yafei; Ji, Xiaosheng; Zhang, Lin; Mi, Xigeng; Huang, He

2013-07-11

427

The Reactions of Acetals with Ozone  

NASA Astrophysics Data System (ADS)

Data concerning the composition of the products of the ozonisation of acetals, the stoichiometry of the process, and the influence of substituents and the structure of acetals on their reactivity, the effect of the polarity of the medium, the activation parameters for the process, and the kinetic isotope effects are surveyed and analysed. At lowered temperatures the process proceeds via a heterolytic mechanism, while with increase of temperature the fraction of ozone consumed due to the formation of free radicals rises. The bibliography includes 60 references.

Rakhmankulov, D. L.; Kuramshin, E. M.; Zlotskii, S. S.

1985-06-01

428

Catalysis of an isotopic exchange between CO 2 and the carboxyl group of acetate by Methanosarcina barkeri grown on acetate  

Microsoft Academic Search

Cell suspensions of Methanosarcina barkeri (strain Fusaro) grown on acetate were found to catalyze the formation of methane and CO2 from acetate (30–40 nmol\\/min·mg protein) and an isotopic exchange between the carboxyl group of acetate and 14CO2 (30–40 nmol\\/min·mg protein). An isotopic exchange between [14C]-formate and acetate was not observed. Cells grown on methanol mediated neither methane formation from acetate

Bernhard Eikmanns; Rudolf K. Thauer

1984-01-01

429

Microfiber Supported Nanofiber Membrane.  

National Technical Information Service (NTIS)

A nanofiber membrane is formed on a microfiber membrane. The nanofiber membrane may be electro sprayed directly onto the microfiber membrane and becomes integrated with the microfiber membrane to form a filter. The microfiber membrane provides structural ...

J. Kameoka K. Nakano

2005-01-01

430

Characterization of microporous membranes using confocal scanning laser microscopy in fluorescence mode  

NASA Astrophysics Data System (ADS)

Confocal Scanning Laser Microscopy (CSLM) in fluorescence mode was used to characterize microporous membranes. Two microfiltration membranes were investigated: a mixed ester (cellulose nitrate/cellulose acetate) 1.2 ?m-rated membrane and a polycarbonate track-etched membrane with cylindrical pores of 2 ?m diameter. Optical sections of the membranes stained with rhodamine and mounted in glycerol were performed at 1 ?m intervals, from 0 to 10 ?m. CSLM was found useful for microporous membrane characterization, as it gives some insight into bulk membrane morphology.

Charcosset, C.; Bernengo, J.-C.

2000-12-01

431

Capillary Electrophoresis and Capillary Electrophoresis–Mass Spectrometry for Structural Analysis of N -Glycans Derived from Glycoproteins  

Microsoft Academic Search

\\u000a This chapter highlights recent developments in the analysis of proteins glycosylated of the amino groups (N) of asparagine residues (i.e., N-glycans) by capillary electrophoresis (CE) and capillary electrophoresis–mass spectrometry (CE-MS). First, the analysis of\\u000a intact glycoproteins by CE and CE-MS is reviewed. In glycoform analysis of a heterogeneous protein due to different glycosylation,\\u000a multiforms are observed on CE. Second, to

Miyako Nakano; Kazuaki Kakehi; Naoyuki Taniguchi; Akihiro Kondo

432

Purified Vesicles of Tobacco Cell Vacuolar and Plasma Membranes Exhibit Dramatically Different Water Permeability and Water Channel Activity  

Microsoft Academic Search

The vacuolar membrane or tonoplast (TP) and the plasma membrane (PM) of tobacco suspension cells were purified by free-flow electrophoresis (FFE) and aqueous two-phase partitioning, with enrichment factors from a crude microsomal fraction of >= 4- to 5-fold and reduced contamination by other cellular membranes. For each purified fraction, the mean apparent diameter of membrane vesicles was determined by freeze-fracture

Christophe Maurel; Frederique Tacnet; Josette Guclu; Jean Guern; Pierre Ripoche

1997-01-01

433

Membrane distillation  

Microsoft Academic Search

This paper provides a state-of-the-art review of the separation process known as membrane distillation, MD. An introduction to the terminology and fundamental concepts associated with MD as well as a historical review of the developments in MD are presented. Membrane properties, transport phenomena, and module design are discussed in detail. A critical evaluation of the MD literature is incorporated throughout

Kevin W. Lawson; Douglas R. Lloyd

1997-01-01

434

DNA sequencing using fluorescence background electroblotting membrane  

DOEpatents

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through amino groups contained on the surface. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to the target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membranes may be reprobed numerous times. No Drawings

Caldwell, K.D.; Chu, T.J.; Pitt, W.G.

1992-05-12

435

Synthesis of Cellulose Acetate from Cotton Byproducts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cotton burr and cottonseed hull are relatively inexpensive cotton byproducts. In an effort to derive greater value out of these natural renewable materials, we have succeeded in converting part of them into cellulose acetate without prior chemical breakdown or physical separation of cellulose, ligni...

436

The PVT Properties of Acetic Acid.  

National Technical Information Service (NTIS)

The PVT properties of acetic acid in the saturated and single-phase regions were measured at temperatures between 448.15 and 603.15 K, at pressures up to about 10 MPa. The experimental results were corrected for decomposition of the sample.

D. A. Lee G. B. Lewis I. J. Lawrenson

1977-01-01

437

Calcium Magnesium Acetate Production and Cost Reduction,  

National Technical Information Service (NTIS)

Calcium Magnesium Acetate (CMA) has been found to be a much less corrosive and environmentally safer substance for effective highway de-icing. However, CMA costs are currently about $640 per ton, while road salt costs $25 per ton. In addition, present CMA...

A. P. Leuschner

1988-01-01

438

Fermentative biohydrogen production from lactate and acetate.  

PubMed

In this study, a continuous-flow stirred tank reactor (CSTR) fed with lactate and acetate was operated to enrich hydrogen-producing bacteria. By varying the influent substrate concentrations and hydraulic retention times (HRT), the volumetric loading rate (VLR) of 55.64 kg-COD/m(3)/day seemed to be optimum for this enriched culture for fermentative hydrogen production from lactate and acetate. The results of batch experiments confirmed that the enriched culture tended to fulfill the e(-) equiv requirement for cell growth at a lower VLR condition (21.77 kg-COD/m(3)/day), while it could largely distribute the e(-) equiv for hydrogen production at a higher VLR condition. However, a maximum lactate/acetate concentration allowed for enriching this culture existed, especially at a lower HRT condition in which wash-out can be an issue for this enriched culture. Finally, the results of cloning and sequencing indicated that Clostridium tyrobutyricum was considered the major hydrogen-producing bacteria in the CSTR fed with lactate and acetate. PMID:22318084

Wu, Chao-Wei; Whang, Liang-Ming; Cheng, Hai-Hsuan; Chan, Kan-Chi

2012-01-05

439

Process for the preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85.degree. and 200.degree. C. and removing the reaction products from the contact zone.

Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

1998-01-01

440

Sisal cellulose whiskers reinforced polyvinyl acetate nanocomposites  

Microsoft Academic Search

Sisal nanowhiskers were used as novel reinforcement to obtain nanocomposites with polyvinyl acetate (PVAc) as matrix phase. They are seen as attractive materials due to the widespread availability and low cost of the sisal source material. Statistical analysis of the sisal whisker length and diameter resulted in average values of 250 nm and 4 nm, respectively, resulting in an average aspect ratio

Nancy Lis Garcia de Rodriguez; Wim Thielemans; Alain Dufresne

2006-01-01

441

Cellulose Derivatives Membranes as Supports for Immobilisation of Enzymes  

Microsoft Academic Search

Cellulosic derivatives (cellulose acetate, cellulose propionate and cellulose acetate-butyrate) as membranes, were prepared in different ways. These were then characterised by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and contact angle evaluation. Subsequently, catalase (H2O2:H2O2 oxireductase; EC 1.11.1.6), alcohol oxidase (Alcohol:oxygen oxireductase; EC 1.1.3.13) and glucose oxidase (ß-D- Glucose:oxygen 1-oxireductase; EC 1.1.3.4) were covalently linked to these membranes. The

D. Murtinho; A. R. Lagoa; F. A. P. Garcia; M. H. Gil

1998-01-01

442

Recent Developments in Instrumentation for Capillary Electrophoresis and Microchip-Capillary Electrophoresis  

PubMed Central

Over the last years there has been an explosion in the number of developments and applications of capillary electrophoresis (CE) and microchip-CE. In part, this growth has been the direct consequence of recent developments in instrumentation associated with CE. This review, which is focused on contributions published in the last five years, is intended to complement the papers presented in this special issue dedicated to Instrumentation and to provide an overview on the general trend and some of the most remarkable developments published in the areas of high voltage power supplies, detectors, auxiliary components, and compact systems. It also includes few examples of alternative uses of and modifications to traditional CE instruments.

Felhofer, Jessica L.; Blanes, Lucas; Garcia, Carlos D.

2010-01-01

443

The Biarsenical-Tetracysteine Motif as a Fluorescent Tag for Detection in Capillary Electrophoresis  

PubMed Central

Biarsenical dyes complexed to tetracysteine motifs have proven to be highly useful fluorescent dyes in labeling specific cellular proteins for microscopic imaging. Their many advantages include membrane permeability, relatively small size, stoichiometric labeling, high affinity, and an assortment of excitation/emission wavelengths. The goal of the current study was to determine whether the biarsenical labeling scheme could be extended to fluorescent detection of analytes in capillary electrophoresis. Recombinant protein or synthesized peptides containing the optimized tetracysteine motif “-C-C-P-G-C-C-” were labeled with biarsenical dyes and then analyzed by MEKC. The biarsenical-tetracysteine complex was stable and remained fluorescent under standard micellar electrokinetic capillary chromatography (MEKC) conditions for peptide and protein separations. The detection limit following electrophoresis in a capillary was less than 3 × 10?20 moles with a simple laser-induced fluorescence system. A mixture of multiple biarsenical-labeled peptides and a protein were easily resolved. Demonstrating that the label did not interfere with bioactivity, a peptide-based enzyme substrate conjugated to the tetracysteine motif and labeled with a biarsenical dye retained its ability to be phosphorylated by the parent kinase. The feasibility of using this label for chemical cytometry experiments was shown by intracellular labeling and subsequent analysis of a recombinant protein possessing the tetracysteine motif expressed in living cells. The extension of the biarsenical-tetracysteine tag to fluorescent labeling of peptides and proteins in chemical separations is a valuable addition to biochemical and cell-based investigations.

Kottegoda, Sumith; Aoto, Phillip C.; Sims, Christopher E.; Allbritton, Nancy L.

2008-01-01

444

Fluorescence two-dimensional difference gel electrophoresis and mass spectrometry based proteomic analysis of Escherichia coli.  

PubMed

Separation and relative quantitation of complex protein mixtures remain two of the most challenging aspects of proteomics. Here an advanced technique called fluorescence difference 2-D gel electrophoresis technology (2D-DIGE) has been applied to a model system study of the Escherichia coli proteome after benzoic acid treatment. The molecular weight and charge matched cyanine dyes enable pre-electrophoretic labelling of control and treated samples which are then mixed and run in the same gel. Pooled control and treated samples labelled with Cy trade mark 3 were used as an internal standard for both Cy5 labelled control and treated E. coli samples. Together with DeCyder trade mark imaging analysis software, more accurate quantitative analysis than conventional two-dimensional polyacrylamide gel electrophoresis was achieved. Using matrix-assisted laser desorption/ionization-time of flight and quadrupole-time of flight mass spectrometry a total of 179 differentially expressed protein spots were identified. These included enzymes, stress related and substrate (e.g. amino acids, maltose, ribose and TRP repressor) binding proteins. Of the spots analysed, 77% contained only one protein species per spot, hence the change in protein expression measured was solely attributed to the identified protein. Many membrane proteins and protein isoforms were identified indicating both adequate solubilization of E. coli samples and potential post-translational modification. The results indicate that the regulatory mechanisms following benzoic acid treatment of E. coli are far more complicated than hitherto expected. PMID:12469338

Yan, Jun X; Devenish, Angelica T; Wait, Robin; Stone, Tim; Lewis, Steve; Fowler, Sue

2002-12-01

445

Gel electrophoresis of a charge-regulated, bi-functional particle.  

PubMed

Adopting a Brinkman fluid model, we analyzed the electrophoresis of a charged-regulated, bi-functional particle containing both acidic and basic functional groups in a gel solution. Both the long-range hydrodynamic effect arising from the liquid drag and the short-range steric effect from particle-polymer interaction are considered. The type of particle considered is capable of simulating both biocolloids such as microorganisms and cells, and particles with adsorbed polyelectrolyte or membrane layer. Our model describes successfully the experimental data in the literature. The presence of gel has the effect of reducing the particle mobility and alleviating double-layer polarization so that the particle behavior is less complicated than that in the case where gel is absent. On the other hand, both the quantitative and qualitative behaviors of a particle depend highly on solution pH and background salt concentration, yielding interesting and significant results. These results provide valuable information for both experimental data interpretation and electrophoresis devices design. PMID:23161269

Hsu, Jyh-Ping; Huang, Chih-Hua; Tseng, Shiojenn

2013-01-30

446

Detection of polymorphisms of human DNA by gel electrophoresis as single-strand conformation polymorphisms  

SciTech Connect

The authors developed mobility shift analysis of single-stranded DNAs on neutral polyacrylamide gel electrophoresis to detect DNA polymorphisms. This method follows digestion of genomic DNA with restriction endonucleases, denaturation in alkaline solution, and electrophoresis on a neutral polyacrylamide gel. After transfer to a nylon membrane, the mobility shift due to a nucleotide substitution of a single-stranded DNA fragment could be detected by hybridization with a nick-translated DNA fragment or more clearly with RNA copies synthesized on each strand of the DNA fragment as probes. As the mobility shift caused by nucleotide substitutions might be due to a conformational change of single-stranded DNAs, we designate the features of single-stranded DNAs as single-strand conformation polymorphisms (SSCPs). Like restriction fragment length polymorphisms (RFLPs), SSCPs were found to be allelic variants of true Mendelian traits, and therefore they should be useful genetic markers. Moreover, SSCP analysis has the advantage over RFLP analysis that it can detect DNA polymorphisms and point mutations at a variety of positions in DNA fragments. Since DNA polymorphisms have been estimated to occur every few hundred nucleotides in the human genome, SSCPs may provide many genetic markers.

Orita, Masato; Iwahana, Hiroyuki; Kanazawa, Hiroshi; Hayashi, Kenshi; Sekiya, Takao (National Cancer Center Research Institute, Tokyo (Japan))

1989-04-01

447

Secretory Immune Response to Membrane Antigens during Giardia lamblia Infection in Humans  

Microsoft Academic Search

The secretory immune response in humans infected with Giardia lamblia was studied by using saliva samples and a membrane-rich protein fraction. The membrane fraction, studied by sodium dodecyl sulfate-polyacryl- amide gel electrophoresis, showed 24 antigen bands, ranging from 170 to 14 kDa. Saliva samples from giardiasis patients showed a heterogeneous response against the membrane fraction when they were assayed by

DISNEY M. ROSALES-BORJAS; JUAN DIAZ-RIVADENEYRA; ANTONIO DONA-LEYVA; SERGIO A. ZAMBRANO-VILLA; CARMEN MASCARO; ANTONIO OSUNA; LIBRADO ORTIZ-ORTIZ; Grupo de Bioquimica; Miguel Oraa

1998-01-01

448

Phenyl Acetate Preparation from Phenol and Acetic Acid: Reassessment of a Common Textbook Misconception.  

ERIC Educational Resources Information Center

|Reassesses a common textbook misconception that "...phenols cannot be esterified directly." Results of experiments are discussed and data tables provided of an effective method for the direct preparation of phenyl acetate. (CS)|

Hocking, M. B.

1980-01-01

449

Detection of Elevated Signaling Amino Acids in Human Diabetic Vitreous by Rapid Capillary Electrophoresis  

PubMed Central

Elevated glutamate is implicated in the pathology of PDR. The ability to rapidly assess the glutamate and amino acid content of vitreous provides a more complete picture of the chemical changes occurring at the diabetic retina and may lead to a better understanding of the pathology of PDR. Vitreous humor was collected following vitrectomies of patients with PDR and control conditions of macular hole or epiretinal membrane. A capillary electrophoresis method was developed to quantify glutamate and arginine. The analysis is relatively fast (<6 minutes) and utilizes a poly(ethylene)oxide and sodium dodecylsulfate run buffer. Both amino acid levels show significant increases in PDR patients versus controls and are comparable to other reports. The levels of vitreal glutamate vary inversely with the degree of observed hemorrhage. The results demonstrate a rapid method for assessment of a number of amino acids to characterize the chemical changes at the diabetic retina to better understand tissue changes and potentially identify new treatments.

Lu, Miao-Jen; Pulido, Jose S.; McCannel, Colin A.; Pulido, Jose E.; Hatfield, R. Mark; F. Dundervill III, Robert; A. Shippy, Scott

2007-01-01

450

Biochemistry of Vibrio cholerae virulence: purification of cholera enterotoxin by preparative disc electrophoresis.  

PubMed Central

Procedures for cholera enterotoxin purification previously developed in this labarotory were not applicable to large-scale purification, and these methods resulted in low yields of pure toxin. An efficient scheme has been developed whereby pure cholera enterotoxin can be obtained from 6 to 8 liters of culture supernatant fluid. This method consists of concentration by membrane ultrafiltration followed by gel filtration and cation-exchange chromatography. Pure cholera enterotoxin of high biological potency was obtained after a final step of preparative acrylamide gel electrophoresis. The degree of purity of the toxin-antigen as well as its biological activity were determined at various setps of purification. This alternate technique for purification is offered because of the widespread interest in cholera enterotoxin as a specific stimulator of adenyl cyclase. Images

Lewis, A C; Richardson, S H; Sheridan, B

1976-01-01

451

Hydrogel plug for independent sample and buffer handling in continuous microchip capillary electrophoresis  

NASA Astrophysics Data System (ADS)

In microchip capillary electrophoresis most frequently electrokinetic sample injection is utilized, which does not allow pressure driven sample handling and is sensitive for pressure drops due to different reservoir levels. For efficient field tests a multitude of samples have to be processed with the least amount of external equipment. We present the use of a hydrogel plug to separate the sample from clean buffer to enable independent sample change and buffer refreshment. In-situ polymerization of the gel does away with complex membrane fabrication techniques. The sample is electrokinetically injected through the gel and subsequently separated by a voltage between the second gel inlet and the buffer outlet. By blocking of disturbing flows by the gel barrier a well-defined ion plug is obtained. After each experiment, the sample and the separation channel can be flushed independently, allowing for a continuous operation mode in order to process multiple samples.

Puchberger-Enengl, Dietmar; Bipoun, Mireille; Smolka, Martin; Krutzler, Christian; Keplinger, Franz; Vellekoop, Michael J.

2013-05-01

452

Fragrance material review on 1,1-dimethyl-2-phenylethyl acetate.  

PubMed

A toxicologic and dermatologic review of 1,1-dimethyl-2-phenylethyl acetate when used as a fragrance ingredient is presented. 1,1-Dimethyl-2-phenylethyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an Aryl Alkyl Alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to 1,1-dimethyl-2-phenylethyl acetate and is not intended as a stand-alone document. Available data were evaluated, then summarized, and includes: physical properties; acute toxicity; skin irritation; mucous membrane (eye) irritation; skin sensitization; elicitation; and toxicokinetics data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22445843

McGinty, D; Letizia, C S; Api, A M

2012-03-15

453

Fragrance material review on 3-phenyl-3-buten-1-yl acetate.  

PubMed

A toxicologic and dermatologic review of 3-phenyl-3-buten-1-yl acetate when used as a fragrance ingredient is presented. 3-Phenyl-3-buten-1-yl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 3-phenyl-3-buten-1-yl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22402309

McGinty, D; Letizia, C S; Api, A M

2012-03-06

454

Fragrance material review on 1,3-dimethyl-3-phenylbutyl acetate.  

PubMed

A toxicologic and dermatologic review of 1,3-dimethyl-3-phenylbutyl acetate when used as a fragrance ingredient is presented. 1,3-Dimethyl-3-phenylbutyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1 to 4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 1,3-dimethyl-3-phenylbutyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, and photoallergy data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22406562

McGinty, D; Letizia, C S; Api, A M

2012-03-03

455

Acetate utilization as a survival strategy of peat-inhabiting Methylocystis spp.  

PubMed

Representatives of the genus Methylocystis are traditionally considered to be obligately methanotrophic bacteria, which are incapable of growth on multicarbon substrates. Here, we describe a novel member of this genus, strain H2s, which represents a numerically abundant and ecologically important methanotroph population in northern Sphagnum-dominated wetlands. This isolate demonstrates a clear preference for growth on methane but is able to grow slowly on acetate in the absence of methane. Strain H2s possesses both forms of methane monooxygenase (particulate and soluble MMO) and a well-developed system of intracytoplasmic membranes (ICM). In cells grown for several transfers on acetate, these ICM are maintained, although in a reduced form, and mRNA transcripts of particulate MMO are detectable. These cells resume their growth on methane faster than those kept for the same period of time without any substrate. Growth on acetate leads to a major shift in the phospholipid fatty acid composition. The re-examination of all type strains of the validly described Methylocystis species showed that Methylocystis heyeri H2(T) and Methylocystis echinoides IMET10491(T) are also capable of slow growth on acetate. This capability might represent an important part of the survival strategy of Methylocystis spp. in environments where methane availability is variable or limited. PMID:23761229

Belova, Svetlana E; Baani, Mohamed; Suzina, Natalia E; Bodelier, Paul L E; Liesack, Werner; Dedysh, Svetlana N

2011-02-01

456

Nonlinear electrophoresis for purification of soil DNA for metagenomics.  

PubMed

Purification of microbial DNA from soil is challenging due to the co-extraction of humic acids and associated phenolic compounds that inhibit subsequent cloning, amplification or sequencing. Removal of these contaminants is critical for the success of metagenomic library construction and high-throughput sequencing of extracted DNA. Using three different composite soil samples, we compared a novel DNA purification technique using nonlinear electrophoresis on the synchronous coefficient of drag alteration (SCODA) instrument with alternate purification methods such as direct current (DC) agarose gel electrophoresis followed by gel filtration or anion exchange chromatography, Wizard DNA Clean-Up System, and the PowerSoil DNA Isolation kit. Both nonlinear and DC electrophoresis were effective at retrieving high-molecular weight DNA with high purity, suitable for construction of large-insert libraries. The PowerSoil DNA Isolation kit and the nonlinear electrophoresis had high recovery of high purity DNA suitable for sequencing purposes. All methods demonstrated high consistency in the bacterial community profiles generated from the DNA extracts. Nonlinear electrophoresis using the SCODA instrument was the ideal methodology for the preparation of soil DNA samples suitable for both high-throughput sequencing and large-insert cloning applications. PMID:22056233

Engel, Katja; Pinnell, Lee; Cheng, Jiujun; Charles, Trevor C; Neufeld, Josh D

2011-10-26

457

Charged Membranes  

NSDL National Science Digital Library

This Teaching Resource provides three animated lessons that describe the storage and utilization of energy across plasma membranes. The “Na,K ATPase” animation explains how these pumps establish the electrochemical gradient that stores energy across plasma membranes. The “ATP synthesizing complexes” animation shows how these complexes transfer energy from the inner mitochondrial membrane to adenosine triphosphate (ATP). The “action potential” lesson explains how charged membranes are used to propagate signals along the axons of neurons. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might employ them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology.

Jack D. Thatcher (Lewisburg;West Virginia School of Osteopathic Medicine REV)

2013-04-16

458

Separation and determination of degradation products of acid orange 7 by capillary electrophoresis/capacitively coupled contactless conductivity detector.  

PubMed

Capillary electrophoresis (CE) with capacitively coupled contactless conductivity detector (C(4)D) was developed to separate azo-dyestuff acid orange 7 (AO7) and its six degradation products. The analyzed products were sulfamic acid, oxalic acid, benzenesulfonic acid, 4-hydroxybenzene sulfonic acid, phthalic acid, and 4-aminobenzene sulfonic acid. In developing the method, types and concentrations of running buffers, injecting voltage and time, and applied voltage were tested to obtain optimum conditions to analyze target compounds. The separation was successfully achieved within 10 min using a fused-silica capillary under the following conditions: 20 mmol L(-1) acetate acid buffer, electrokinetic injection of -12 kV × 10 s, and applied voltage of -13 kV. The developed method was applied to analyze degradation products in situ during the reaction of AO7 with Fenton reagent (Fe(II)+H2O2 at pH 4.0). PMID:23622525

Wang, Xin; Xiong, Ya; Xie, Tianyao; Sharma, Virender K; Tu, Yuting; Yang, Jiannan; Tian, Shuanghong; He, Chun

2013-03-22

459

Nasal pungency, odor, and eye irritation thresholds for homologous acetates.  

PubMed

We measured detection thresholds for nasal pungency (in anosmics), odor (in normosmics) and eye irritation employing a homologous series of acetates: methyl through octyl acetate, decyl and dodecyl acetate. All anosmics reliably detected the series up to heptyl acetate. Only the anosmics without smell since birth (congenital) reliably detected octyl acetate, and only one congenital anosmic detected decyl and dodecyl acetate. Anosmics who lost smell from head trauma proved to be selectively less sensitive. As expected, odor thresholds lay well below pungency thresholds. Eye irritation thresholds for selected acetates came close to nasal pungency thresholds. All three types of thresholds decreased logarithmically with carbon chain length, as previously seen with homologous alcohols and as seen in narcotic and toxic phenomena. Results imply that nasal pungency for these stimuli rests upon a physical, rather than chemical, interaction with susceptible mucosal structures. When expressed as thermodynamic activity, nasal pungency thresholds remain remarkably constant within and across the homologous series of acetates and alcohols. PMID:1763117

Cometto-Muñiz, J E; Cain, W S

1991-08-01

460

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5892 a -Tocopherol acetate. (a) Product. a -Tocopherol acetate....

2013-04-01