These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

A simple cellulose acetate membrane-based small lanes technique for protein electrophoresis.  

PubMed

Combining electrophoresis with a cellulose acetate membrane-based technique, we developed a simple and low-cost method, named cellulose acetate membrane-based small lanes (CASL), for protein electrophoresis. A home-made capillary plotter controlled by a 3D moving stage was used to create milli-to-micro channels by printing poly(dimethylsiloxane) on to a hydrophilic cellulose acetate membrane. In the hydrophilic channels, 5 nL protein mixture was separated on the basis of electro-migration under an electric field. Compared with polyacrylamide gel electrophoresis (PAGE), CASL resulted in higher protein signal intensity for separation of mixtures containing the same mass of protein. The platform was easily fabricated at low cost (approx. $0.005 for each 1-mm-wide channel), and separation of three protein mixtures was completed in 15 min. Both electrophoresis time and potential affected the separation. Rather than chromatographic separation, this method accomplished application of microchannel techniques for cellulose acetate membrane-based protein electrophoresis. It has potential in proteomic analysis, especially for rapid, low-cost, and low-volume sample analysis in clinical diagnosis. PMID:22752445

Na, Na; Liu, Tingting; Yang, Xiaojun; Sun, Binjie; Ouyang, Jenny; Ouyang, Jin

2012-08-01

2

Two-dimensional electrophoresis of membrane proteins  

Microsoft Academic Search

One third of all genes of various organisms encode membrane proteins, emphasizing their crucial cellular role. However, due\\u000a to their high hydrophobicity, membrane proteins demonstrate low solubility and a high tendency for aggregation. Indeed, conventional\\u000a two-dimensional gel electrophoresis (2-DE), a powerful electrophoretic method for the separation of complex protein samples\\u000a that applies isoelectric focusing (IEF) in the first dimension and

Ralf J. Braun; Norbert Kinkl; Monika Beer; Marius Ueffing

2007-01-01

3

Ammonia permeability of a cellulose acetate membrane  

Microsoft Academic Search

A mechanism is proposed for ammonia transport across a cellulose acetate membrane. The transport is shown to have a sorption\\u000a character, with the formation of hydrogen bonds between ammonia molecules and the polymer. Our experiments demonstrate that\\u000a the membrane can be regenerated in the course of gas separation. The ideal separation factors in the ammonia-nitrogen and\\u000a ammonia-hydrogen systems are determined.

I. V. Vorotyntsev; P. N. Drozdov; N. V. Karyakin

2006-01-01

4

Fabricating PFPE Membranes for Capillary Electrophoresis  

NASA Technical Reports Server (NTRS)

A process has been developed for fabricating perfluoropolyether (PFPE) membranes that contain microscopic holes of precise sizes at precise locations. The membranes are to be incorporated into laboratory-on-a-chip microfluidic devices to be used in performing capillary electrophoresis. The present process is a modified version of part of the process, described in the immediately preceding article, that includes a step in which a liquid PFPE layer is cured into solid (membrane) form by use of ultraviolet light. In the present process, one exploits the fact that by masking some locations to prevent exposure to ultraviolet light, one can prevent curing of the PFPE in those locations. The uncured PFPE can be washed away from those locations in the subsequent release and cleaning steps. Thus, holes are formed in the membrane in those locations. The most straightforward way to implement the modification is to use, during the ultraviolet-curing step, an ultraviolet photomask similar to the photomasks used in fabricating microelectronic devices. In lieu of such a photomask, one could use a mask made of any patternable ultraviolet-absorbing material (for example, an ink or a photoresist).

Lee, Michael C.; Willis, Peter A.; Greer, Frank; Rolland, Jason

2009-01-01

5

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

6

Fucoidan as an inhibitor of thermally induced collagen glycation examined by acetate electrophoresis.  

PubMed

Non-enzymatic glycation (Maillard reaction) in vitro could be a simple method to obtain glycoconjugates for studying their biological properties. Hence, fucoidan was retained by acetate electrophoresis indicating a strong interaction with the protein. A loss of colour in fucoidan bands was found for samples incubated with collagen as compared with samples of free fucoidan. Also under in vitro conditions at 100°C - simulating a sudden burn incident - fucoidan binds with collagen as a result of the Maillard reaction. In contrast, the colour of the fucoidan bands intensified for samples incubated with collagen, with the addition of glucose. Electrophoretic analyses were carried out after heating the samples to a temperature simulating a burn incident. The bands were found to intensify for samples incubated with collagen during a 30-day-long incubation. Thus, spontaneous in vitro glycation - i.e. without the addition of glucose - was confirmed. This process is highly intensified both by the temperature and time of incubation. For a sample incubated in vitro in a fucoidan solution containing glucose, glycation was confirmed in a preliminary FTIR and acetate electrophoresis examinations, occurring in collagen obtained from chicken skins. In particular, a new band emerging around 1746 cm(-1) was observed for above samples, as was its increasing intensity, as compared with samples without the addition of glucose. In the collagen glycation assay, while glucose reacts with collagen and forms cross-linked aggregates, fucoidan decreases the process of aggregation and recovery of native collagen. PMID:24853731

Pielesz, Anna; Paluch, Jadwiga

2014-08-01

7

Continuous-flow electrophoresis: Membrane-associated deviations of buffer pH and conductivity  

NASA Technical Reports Server (NTRS)

The deviations in buffer pH and conductivity which occur near the electrode membranes in continuous-flow electrophoresis were studied in the Beckman charged particle electrophoresis system and the Hanning FF-5 preparative electrophoresis instrument. The nature of the membranes separating the electrode compartments from the electrophoresis chamber, the electric field strength, and the flow rate of electrophoresis buffer were all found to influence the formation of the pH and conductivity gradients. Variations in electrode buffer flow rate and the time of electrophoresis were less important. The results obtained supported the hypothesis that a combination of Donnan membrane effects and the differing ionic mobilities in the electrophoresis buffer was responsible for the formation of the gradients. The significance of the results for the design and stable operation of continuous-flow electrophoresis apparatus was discussed.

Smolka, A. J. K.; Mcguire, J. K.

1978-01-01

8

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

9

Dissolution control of mg by cellulose acetate-polyelectrolyte membranes.  

PubMed

Cellulose acetate (CA)-based membranes are used for Mg dissolution control: the permeability of the membrane is adjusted by additions of the polyelectrolyte, poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA). Spin-coated films were characterized with FT-IR, and once exposed to an aqueous solution the film distends and starts acting as a membrane which controls the flow of ions and H2 gas. Electrochemical measurements (linear sweep voltammograms, open-circuit potential, and polarization) show that by altering the CA:PDMAEMA ratio the dissolution rate of Mg can be controlled. Such a control over Mg dissolution is crucial if Mg is to be considered as a viable, temporary biomedical implant material. Furthermore, the accumulation of corrosion products between the membrane and the sample diminishes the undesirable effects of high local pH and H2 formation which takes place during the corrosion process. PMID:25426707

Yliniemi, Kirsi; Wilson, Benjamin P; Singer, Ferdinand; Höhn, Sarah; Kontturi, Eero; Virtanen, Sannakaisa

2014-12-24

10

Cellulose membranes for reverse osmosis Part I. RO cellulose acetate membranes including a composite with polypropylene  

Microsoft Academic Search

With the aim of obtaining RO membranes for brackish water desalination from purified celluloses (cotton linters and bleached bagasse pulp), two reactions (heterogeneous and homogeneous) were applied for the synthesis of cellulose acetate (CA). The efficiency of the membranes was measured and compared with those prepared from purchased CA and prepared CA by acetylation of imported high-grade viscose wood pulp.

Houssni El-Saied; Altaf H. Basta; Barsoum N. Barsoum; Mohamed M. Elberry

2003-01-01

11

Electrophoresis  

NSDL National Science Digital Library

Electrophoresis involves the movement of electrically charged substances under the influence of an electric field. This website demonstrates electrophoresis by providing a java applet which virtually applies an electric field across an agarose or polyacrylamide electrophoresis gel in which biological macromolecules are placed. The applet shows how the molecules move and at the end of the experiment plots the logarithm of the molecular weight versus the logarithm of the distance moved. This tutorial is one of a large collection of tutorials on electricity and magnetism available from Molecular Expressions.

Davidson, Michael

2010-12-29

12

Isolation of monodisperse nanodisc-reconstituted membrane proteins using free flow electrophoresis.  

PubMed

Free flow electrophoresis is used for rapid and high-recovery isolation of homogeneous preparations of functionally active membrane proteins inserted into nanodiscs. The approach enables isolation of integral and membrane anchored proteins and is also applicable following introduction of, e.g., fluorescent tags. Preparative separation of membrane protein loaded nanodiscs from empty nanodiscs and protein aggregates results in monodisperse nanodisc preparations ideal for structural and functional characterization using biophysical methods. PMID:23458128

Justesen, Bo Højen; Laursen, Tomas; Weber, Gerhard; Fuglsang, Anja Thoe; Møller, Birger Lindberg; Pomorski, Thomas Günther

2013-04-01

13

Original article Two-dimensional gel electrophoresis of membrane  

E-print Network

— A membrane fraction was isolated from the ectomycorrhizal fungi Pisolithus tinctorius globulus / Pisolithus tinctorius / ectomycorrhiza / elec- trophoresis / membrane protein / symbiosis ectomycorhiziens Pisolithus tinctorius et Cenococcum geophilum et d'ectomycorhizes d'eucalyptus. L'observation par

Paris-Sud XI, Université de

14

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

15

Journal of Membrane Science 205 (2002) 1121 Macrovoid pore formation in dry-cast cellulose acetate  

E-print Network

Journal of Membrane Science 205 (2002) 11­21 Macrovoid pore formation in dry-cast cellulose acetate of macrovoid (MV) pores formed during the dry-casting of cellulose acetate (CA)/acetone/water casting solutions were cast in low-gravity (low-g) (KC-135) and normal-gravity (1-g) (ground-based control) from CA

Shvartsman, Stanislav "Stas"

16

Demystifying Hardy-Weinberg: Using Cellulose Acetate Electrophoresis of the Lap Locus to Study Population Genetics in White Campion (Silene latifolia)  

NSDL National Science Digital Library

This laboratory exercise could used as an introductory biology lab and/or an upper level course lab, with minor adjustments, covering ecology, evolution, population genetics and physiology. Population genetics is explored using seedlings from several population of the perennial herb white campion, (Silene latifolia), scientific method,cellulose acetate protein electrophoresis and the Hardy-Weinberg Equilibrium Theory.

Patricia A. Peroni (Davidson College;); David E. McCauley (Vanderbilt University;)

1999-01-01

17

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

18

Dog pancreatic microsomal-membrane polypeptides analysed by two-dimensional gel electrophoresis.  

PubMed Central

The two-dimensional polyacrylamide-gel electrophoresis technique of O'Farrell [(1975) J. Biol. Chem 250, 4007-4021] was applied to resolve and analyse the polypeptide composition of dog pancreatic rough microsomal membranes, which were shown to be active in co-translational processing of preprolactin synthesized from pituitary mRNA in a translation system in vitro. About 100 polypeptides are resolved. Treatment of rough microsomal membranes with EDTA and high KCl concentration yielded membranes stripped of their ribosomes with retention of activity for translocation and processing. Stripped microsomal membranes showed a selective concentration of approximately 25 polypeptides in the membranes when analysed by two-dimensional polyacrylamide-gel electrophoresis. The two-dimensional electrophoretic profile was catalogued into polypeptides that are glycoproteins, those that contain free thiol groups disposed at the cytosolic surface of microsomal vesicles and those that are of secretory origin but have been entrapped in the microsomal preparation. Several secretory components, including amylase, procarboxypeptidases, lipase and anionic trypsinogen, were tentatively identified among the microsomal polypeptides. The rough and stripped microsomal membranes from dog pancreas show a characteristic set of seven major acidic polypeptides, which are also identifiable in microsomal-membrane preparations isolated from dog liver and rat liver. One of these polypeptides was identified as protein disulphide-isomerase (EC 5.3.4.1). Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:6696719

Kaderbhai, M A; Austen, B M

1984-01-01

19

Transport of aromatic hydrocarbons through poly(ethylene-co-vinyl acetate) membranes  

Microsoft Academic Search

Solvent transport of aromatic hydrocarbons through both crosslinked and uncrosslinked poly(ethylene-co-vinyl acetate) (EVA) membranes has been studied using sorption gravimetric analysis. EVA was crosslinked by using dicumyl peroxide (DCP). Diffusion through membranes containing different loading of DCP was also carried out to follow the effect of crosslinking density on diffusion. It was found that as the extent of crosslinking increases

M. G. Kumaran

1997-01-01

20

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. PMID:15941475

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

2005-01-01

21

Studies on cellulose acetate Polymethylmethacrylate and Polystyrene blend ultrafiltration Membranes;.  

E-print Network

??Membrane separation techniques are being used in various newlineindustries such as chemical pharmaceutical and metal finishing industries newlineThese techniques allow not only energy and cost… (more)

Vidya S

2014-01-01

22

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. PMID:23429293

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

2013-01-01

23

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

PubMed

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. PMID:23429293

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

2013-01-01

24

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

2013-07-17

25

A comparative study on the chitosan membranes prepared from glycine hydrochloride and acetic acid.  

PubMed

In this study, glycine hydrochloride (Gly·HCl) is confirmed to be a promising solvent for dissolving native chitosan and preparing regenerated chitosan membrane. As compared with the chitosan membrane prepared from traditional acetic acid, the membrane prepared from Gly·HCl by dry technique shows excellent tensile strength and initial modulus, i.e. 103.8MPa and 3.2GPa, respectively, which is superior to any chitosan membrane and most chitosan blend membranes reported in literatures. Besides, scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FT-IR) were used to visualize the difference between the two kind of regenerated chitosan membranes. The SEM results show that the membrane prepared from Gly·HCl by dry technique presents a novel structure, which ensures its high tenacity. Furthermore, the chitosan microporous membranes were also prepared using PEG as porogen. PMID:23121935

Ma, Bomou; Li, Xiang; Qin, Aiwen; He, Chunju

2013-01-16

26

Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution  

NASA Technical Reports Server (NTRS)

Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

Wydeven, T.; Leban, M.

1973-01-01

27

Cellulose acetate-coated ?-alumina ceramic composite tubular membranes for wastewater treatment  

Microsoft Academic Search

A novel method was developed to reduce the pore size of microporous ceramic tubular membranes by coating their inner surfaces using cellulose acetate solution forming a thin coating of ~35 ?m. Three tubular membrane configurations viz., 1-channel, 7-channel and 19-channel, hollow tubular having an identical pore size of 1.2 ?m and apparent porosity of 35 vol.% were tested for pollutants

S. K. Nataraj; S. Roy; M. B. Patil; M. N. Nadagouda; W. E. Rudzinski; T. M. Aminabhavi

2011-01-01

28

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

29

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

30

Study of ABO blood types by combining membrane electrophoresis with surface-enhanced Raman spectroscopy  

NASA Astrophysics Data System (ADS)

The molecular characterization of ABO blood types, which is clinically significant in blood transfusion, has clinical and anthropological importance. Polymerase chain reaction sequence-based typing (PCR-SBT) is one of the most commonly used methods for the analysis of genetic bases of ABO blood types. However, such methods as PCR-SBT are time-consuming and are high in demand of equipments and manipulative skill. Here we showed that membrane electrophoresis based SERS method employed for studying the molecular bases of ABO blood types can provide rapidand easy-operation with high sensitivity and specificity. The plasma proteins were firstly purified by membrane electrophoresis and then mixed with silver nanoparticles to perform SERS detection. We use this method to classify different blood types, including blood type A (n=13), blood type B (n=9) and blood type O (n=10). Combination of principal component analysis (PCA) and liner discriminant analysis (LDA) was then performed on the SERS spectra of purified albumin, showing good classification results among different blood types. Our experimental outcomes represent a critical step towards the rapid, convenient and accurate identification of ABO blood types.

Wang, Jing; Lin, Juqiang; Huang, Zufang; Sun, Liqing; Shao, Yonghong; Lu, Peng; Shi, Wei; Lin, Jinyong; Chen, Rong

2012-12-01

31

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 PMID:7081216

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

1982-01-01

32

The identification of rat intestinal membrane enzymes after electrophoresis on polyacrylamide gels containing sodium dodecyl sulphate.  

PubMed Central

Brush-border membranes were isolated from the rat small intestine and then treated with sodium dodecyl sulphate under non-reducing conditions at room temperature. Analysis of the solubilized components by polyacrylamide-gel electrophoresis identified three major glycoproteins that co-migrate with glucoamylase-maltase-sucrase, lactase and isomaltase-maltase-sucrase activities. High activities of alkaline phosphatase and trehalase were detectable, but they could not be attributed to distinct co-migrating protein bands. Analysis of mucosa from the distal small intestine by the same methods showed a pattern of bands different from that obtained with the proximal intestine, which appeared to correlate with the relative deficiency of some of the enzymes in the distal region. PMID:697763

Hauri, H P; Green, J R

1978-01-01

33

Application of charge shift electrophoresis to antigenic analysis of mycoplasmic membranes by two-dimensional (crossed) immunoelectrophoresis.  

PubMed Central

Both the anodic migration and resolution of membrane antigens of Mycoplasma arginini were greatly improved in two-dimensional immunoelectrophoresis by incorporating both a neutral detergent, Triton X-100, and an anionic detergent, sodium deoxycholate, in the agarose support for first phase electrophoresis. The mobility of cytoplasmic antigens was unaffected at concentrations of 0.1% or less of sodium deoxycholate. Images PMID:669825

Alexander, A G; Kenny, G E

1978-01-01

34

Dehydration of water/pyridine mixtures by pervaporation using cellulose acetate/ polyacrylonitrile blend membrane.  

PubMed

Cellulose acetate/ polyacrylonitrile (CA/PAN) membranes were prepared and used to separate pyridine / water mixtures by pervaporation. The membranes were characterized through SEM. The effects of feed concentration, operation temperature and downstream pressure on the separation performance were evaluated. Experimental results indicated the increase of operation temperature could raise the permeation flux and the separation factor, while increasing feed concentration and downstream pressure would raise the separation factor and decrease the permeation flux. Under the conditions that pyridine solution was 99 wt.%, operation temperature was 323 K and downstream pressure was 20 mmHg, the CA/PAN blend membrane showed its best separation performance that the permeation flux was 56.g.m-2 h-1 and the separation factor was 182. PMID:21866770

Lv, J H; Xiao, G M

2011-01-01

35

Cellulose acetate hollow fiber ultrafiltration membranes made from CA\\/PVP 360 K\\/NMP\\/water  

Microsoft Academic Search

Hydrophilic hollow fiber ultrafiltration (UF) membranes have been prepared from a new dope solution containing cellulose acetate (CA)\\/poly(vinyl pyrrolidone) (PVP 360K)\\/N-methyl-2-pyrrolidone (NMP)\\/water with a mass ratio of 19.0\\/5.0\\/74.8\\/1.2 by using a dry-jet wet spinning process. The effect of air-gap length was studied. The as-spun fibers were post-treated by means of a hypochlorite solution of 200mgl?1 (200ppm) over different duration. The

Jian-Jun Qin; Ying Li; Leng-Siang Lee; Hsiaowan Lee

2003-01-01

36

Pervaporation of water and ethanol using a cellulose acetate butyrate membrane  

SciTech Connect

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 temperature (24 C) for water and ethanol using a cellulose acetate butyrate membrane. The results show that the P. values are essentially unaffected by the upstream pressure, and that they are generally higher than the literature values of saturation vapor pressure at 24 C. Further, the values for A/[delta] and B/[delta] tend to increase with increased upstream pressure for both systems studied. These results are discussed.

Wu, W.S.; Lau, W.W.Y.; Rangaiah, G.P.; Sourirajan, S. (National Univ. of Singapore (Singapore). Dept. of Chemical Engineering)

1993-10-15

37

Tunable membranes for free-flow zone electrophoresis in PDMS microchip using guided self-assembly of silica microbeads.  

PubMed

In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow zone electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow zone electrophoresis, we used silica or polystyrene microbeads between 3-6 ?m in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow zone electrophoresis with tunable pore size as well as surface charge polarity. PMID:24251795

Song, Yong-Ak; Wu, Lidan; Tannenbaum, Steven R; Wishnok, John S; Han, Jongyoon

2013-12-17

38

Acetate and formate uptake into vesicles isolated from the basolateral region of the plasma membrane of ovine parotid acinar cells.  

PubMed

The transport of acetate and formate into plasma membrane vesicles derived from the basolateral face of the ovine parotid acinar cell has an absolute requirement for an anion to be present within the intravesicular space: bicarbonate, formate, acetate, propionate, and butyrate support the uptake of either acetate or formate. A pH gradient across the vesicle membrane, pHi 7.4, pH0 5.5, enhances the uptake of formate, but not acetate. There is no direct relationship between the rate of exchange and the degree of protonation of formate or acetate in the extravesicular medium. The process is saturable and can be inhibited by a range of functional group reagents. When mannitol is the main external osmoticum, the uptake of acetate and formate is still rapid; thus, no other ions are involved in the process apart from the external formate or acetate and the intravesicular anion. This activity could play a major role in the provision of energy in ruminant tissues. PMID:10364465

Nguyen, H V; Beechey, R B

1999-06-16

39

Phorbol myristate acetate stimulates ATP-dependent calcium transport by the plasma membrane of neutrophils.  

PubMed Central

We studied the effect of phorbol myristate acetate (PMA) on the plasma membrane ATP-dependent calcium pump in neutrophils. Plasma membrane-enriched fractions ("podosomes") from PMA-stimulated guinea pig neutrophils exhibited a twofold stimulation of ATP-dependent calcium transport when compared with control podosomes. The stimulatory effect was rapid (beginning less than 2 min after exposure to PMA) and reached maximal values within 5 min. PMA increased the maximum velocity but not the affinity of the calcium pump for Ca++. Pump activation was not preceded by a rise in cytosolic free calcium concentration [Ca++]i, as assessed by the intracellularly trapped fluorescent calcium indicator Quin 2, but instead slightly lowered [Ca++]i and prevented the rise in [Ca++]i normally induced by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine. These results suggest that the calcium pump in the plasma membrane of neutrophils may be stimulated by calcium-independent pathways, and that this activation could be one of the earliest events mediating some of the effects of phorbol esters. PMID:6323530

Lagast, H; Pozzan, T; Waldvogel, F A; Lew, P D

1984-01-01

40

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

41

Preparation, characterization and release of amoxicillin from cellulose acetate and poly(vinyl pyrrolidone) coaxial electrospun fibrous membranes  

Microsoft Academic Search

Electrospinning is a method that has been used to prepare polymeric fibers, with diameters ranging from nanometers to a micrometer of polymers such as cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP), and to develop membranes with applications in microencapsulation, for controlled release of drugs and for chemical and biological sensors. This work shows the feasibility and optimal conditions for the

M. M. Castillo-Ortega; A. Nájera-Luna; D. E. Rodríguez-Félix; J. C. Encinas; F. Rodríguez-Félix; J. Romero; P. J. Herrera-Franco

2011-01-01

42

Development and optimization of a capillary zone electrophoresis technique for simultaneous determination of miconazole nitrate and hydrocortisone acetate in a cream pharmaceutical formulation.  

PubMed

A simple, fast, inexpensive, and reliable capillary zone electrophoresis (CZE) method for the determination of a mixture of miconazole nitrate (MCZ) and hydrocortisone acetate (HCZ) in a cream formulation has been developed and validated. Optimum conditions were sodium dihydrogen phosphate buffer (50 mM, pH 4) and 30 kV applied voltage in a 85 cm x 75 pm id capillary. Direct UV detection at 230 nm led to adequate sensitivity without interference from the sample excipients. MCZ and HCZ migrated in approximately 165 and 415 s, respectively. The analytical curves had a coefficient of correlation, r, of 0.9999 and 0.9996 for MCZ and HCZ, respectively. The LOD and LOQ were 0.28 and 0.93 microg/mL for MCZ and 0.38 and 1.27 microg/mL for HCZ, respectively. Thus, excellent accuracy and precision were obtained. Recoveries varied from 98 to 102%, and intraday and interday precision, calculated as the RSD, were less than 2.0% for each drug. The proposed CZE method displayed advantageous performance characteristics and can be considered suitable for QC of the MCZ and HCZ cream formulation. PMID:24645507

Korany, Mohamed A; Maher, Hadir M; Galal, Shereen M; Ragab, Marwa A A

2013-01-01

43

Membrane-supported liquid-liquid-liquid microextraction combined with anion-selective exhaustive injection capillary electrophoresis-ultraviolet detection for sensitive analysis of phytohormones.  

PubMed

A novel method based on off-line membrane-supported liquid-liquid-liquid microextraction (MS-LLLME) combined with on-column anion-selective exhaustive injection (ASEI) capillary electrophoresis-ultraviolet (CE-UV) detection was established for the analysis of seven phytohormones (abscisic acid (ABA), jasmonic acid (JA), 2,4-dichlorophenoxyacetic acid (2,4-D), 1-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA), salicylic acid (SA) and gibberellic acid (GA)). In MS-LLLME, the target phytohormones were extracted from the acid donor phase to the alkaline acceptor phase, and the acceptor solutions were directly analyzed by ASEI-CE-UV. Under the optimal experimental conditions, the analytical performance of the method was evaluated. The limits of detection (LODs) of ABA, JA, 2,4-D, NAA, IAA, SA and GA were determined to be 1.00, 2.21, 0.33, 0.17, 0.67, 0.05 and 16.5ng/mL, respectively. The relative standard deviations (RSDs, n=7) ranged from 4.7% to 12.9%, and the enrichment factors were in the range of 307 to 20,160. The proposed method was successfully applied for the determination of multiple phytohormones in banana, cabbage and cucumber extracts, and ABA, IAA and SA were detected in these samples. The recoveries for the spiked samples were in the range of 79.0 to 116.4%. The proposed method was demonstrated to be suitable for the simultaneous quantification of multiple phytohormones with high sensitivity and good sample cleanup ability. PMID:24720904

Huang, Linfang; He, Man; Chen, Beibei; Hu, Bin

2014-05-23

44

Tuning aluminum spatial distribution in ZSM-5 membranes: a new strategy to fabricate high performance and stable zeolite membranes for dehydration of acetic acid.  

PubMed

A novel ZSM-5 membrane with a low Si/Al ratio and homogeneous aluminum spatial distribution was achieved from an organic template-free inorganic gel in the presence of both OH(-) and F(-) ions and the obtained ZSM-5 membrane exhibited excellent selectivity and high flux and stability for dehydration of acetic acid in a wide AcOH content range. PMID:25316372

Yang, Jianhua; Li, Liangqing; Li, Wanze; Wang, Jinqu; Chen, Zan; Yin, Dehong; Lu, Jinming; Zhang, Yan; Guo, Hongchen

2014-12-01

45

SEM study of the morphology of asymmetric cellulose acetate membranes produced from recycled agro-industrial residues: sugarcane bagasse and mango seeds  

Microsoft Academic Search

Cellulose, obtained both from sugarcane bagasse and mango seeds, was used for synthesizing cellulose acetate in order to produce\\u000a asymmetric membranes. These were compared to membranes of commercial cellulose acetate (Rhodia). All produced membranes were\\u000a asymmetric, characterized by the presence of a dense skin and a porous support. Differences regarding the morphology of the\\u000a surfaces as well as of the

Moacir Fernandes Ferreira Júnior; Elaine Angélica Ribeiro Mundim; Guimes Rodrigues Filho; Carla da Silva Meireles; Daniel Alves Cerqueira; Rosana Maria Nascimento de Assunção; Marcos Marcolin; Mara Zeni

2011-01-01

46

Capillary electrophoresis as a tool for a cost-effective assessment of the activity of plant membrane enzyme chlorophyllase.  

PubMed

The potential of the capillary electrophoresis-based enzymatic assay has been demonstrated in case of a typical plant membrane enzyme - chlorophyllase. An efficient, automated and rapid semi-quantitative method has been developed, which allowed us to assess the activity of the enzyme via two strategies. Firstly, a reaction conducted in a vial placed directly on the sample tray was combined with the concomitant separation and detection of reagents. The method was used to monitor the reaction progress. Secondly, an on-line approach was applied by using an electrophoretically mediated mixing. The reaction was performed in-capillary, resulting in an extreme reduction of the reagent amounts required for a single run. Both methods were effective in the assessment of the activity of a membrane enzyme, a member of protein class known to pose experimental difficulties. This article is protected by copyright. All rights reserved. PMID:24123178

Nowak, Pawe?; Michalik, Maciej; Fiedor, Leszek; Wo?niakiewicz, Micha?; Ko?cielniak, Pawe?

2013-10-01

47

Magnetic Targeted Delivery of Dexamethasone Acetate across the Round Window Membrane in Guinea Pigs  

PubMed Central

Hypothesis Magnetically susceptible PLGA nanoparticles will effectively target the round window membrane (RWM) for delivery of dexamethasone-acetate (Dex-Ac) to the scala tympani. Background Targeted delivery of therapeutics to specific tissues can be accomplished using different targeting mechanisms. One technology includes iron oxide nanoparticles, susceptible to external magnetic fields. If a nanocomposite composed of biocompatible polymer (PLGA), magnetite, and Dex-Ac can be pulled into and across the mammalian RWM, drug delivery can be enhanced. Method In vitro targeting and release kinetics of PLGA-magnetite-Dex-Ac nanoparticles first were measured using a RWM model. Next, these optimized nanocomposites were targeted to the RWM by filling the niche in anesthetized guinea pigs. A permanent magnet was placed opposite the RWM for 1 hour. Cochlear soft tissues, perilymph, and RWM were harvested after euthanasia and steroid levels were measured using HPLC. Results Membrane transport, in vitro, proved optimal targeting using a lower particle magnetite concentration (1 versus 5 or 10 mg/ml). In vivo targeted PLGA-magnetite-Dex-Ac particles had an average size of 482.8 ± 158 nm (DLS) and an average zeta potential ?19.9 ± 3.3 mV. In 1 hour, there was significantly increased cochlear targeted delivery of Dex or Dex-Ac, compared with diffusion alone. Conclusion Superparamagnetic PLGA-magnetite-Dex-Ac nanoparticles under an external magnetic field (0.26 mT) for 1 hour significantly increased Dex-Ac delivery to the inner ear. The RWM was not completely permeated and also became loaded with nanocomposites, indicating that delivery to the cochlea would continue for weeks by PLGA degradation and passive diffusion. PMID:23187928

Du, Xiaoping; Chen, Kejian; Kuriyavar, Satish; Kopke, Richard D.; Grady, Brian P.; Bourne, David H.; Li, Wei; Dormer, Kenneth J.

2012-01-01

48

Quantifying contribution of synthrophic acetate oxidation to methane production in thermophilic anaerobic reactors by membrane inlet mass spectrometry.  

PubMed

A unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize silage, and deep litter was incubated with 100 mM of [2-(13)C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days of incubation, the proportion of methane derived from reduction of CO2 had increased significantly and reached up to 87% of total methane, suggesting that synthrophic acetate oxidation coupled to hydrogenotrophic methanogenesis (SAO-HM) played an important role in the degradation of acetate. This study provided a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic digestion model (ADM1), which strongly emphasizes the importance of the acetoclastic methanogenesis. PMID:24437339

Mulat, Daniel Girma; Ward, Alastair James; Adamsen, Anders Peter S; Voigt, Niels Vinther; Nielsen, Jeppe Lund; Feilberg, Anders

2014-02-18

49

Development of cellulose acetate propionate membrane for separation of ethanol and ethyl tert-butyl ether mixtures  

SciTech Connect

For pervaporation separation of ethanol and ethyl tert-butyl ether mixtures, a cellulose acetate propionate membrane was chosen as the experimental membrane because of its high selectivity and good mass fluxes. The properties of the membranes were evaluated by the pervaporation separation of mixtures of ethyl tert-butyl ether/ethanol and the sorption experiments. The experimental results showed that the selectivity and the permeates depend on the ethanol concentration in the feed and the experimental temperature. With increases of the ethanol weight fraction in the feed and the temperature, the total and partial mass fluxes increased. With respect to the temperature, ethanol mass flux obeys the Arrhenius equation. The selectivity of this membrane decreases as the temperature and the ethanol concentration in the feed increase. This membrane shows special characteristics at the azeotropic composition. In the vicinity of the azeotropic point, minimum values of ethanol concentration in the permeate and in sorption solution are obtained. The swelling ratios increase when temperature and the ethanol concentration in the feed are increasing. The ethanol concentration in the sorption solution is also influenced by the temperature and the mixture`s composition. When the temperature increases, the sorption selectivity of the membrane decreases.

Luo, G.S.; Niang, M.; Schaetzel, P. [Laboratoire D`Automatique et de Procedes, Caen (France)

1997-04-01

50

Electrophoresis and isoelectric focusing of whole cell and membrane proteins from the extremely halophilic archaebacteria  

NASA Technical Reports Server (NTRS)

The subunits from two purified halobacterial membrane enzymes (ATPase and nitrate reductase) behaved differently with respect to isoelectric focusing, silver staining and interaction with ampholytes. Differential behavior was also observed in whole cell proteins from Halobacterium saccharovorum regarding resolution in two-dimensional gels and silver staining. It is proposed that these differences reflect the existence of two classes of halobacterial proteins.

Stan-Lotter, Helga; Lang, Frank J., Jr.; Hochstein, Lawrence I.

1989-01-01

51

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

52

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

2010-09-10

53

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

54

Comparison of radial immunodiffusion and alkaline cellulose acetate electrophoresis for quantitating elevated levels of fetal hemoglobin (HbF): application to evaluating patients with sickle cell disease treated with hydroxyurea.  

PubMed

Radial immunodiffusion (RID), alkaline cellulose acetate electrophoresis, and high-performance liquid chromatography (HPLC) were compared for quantitating the elevated (> 10%) level of fetal hemoglobin (HbF) found in the red blood cells of sickle cell disease patients undergoing treatment with hydroxyurea. HPLC- and electrophoresis-determined values were comparable. The RID-determined values were higher, in many cases twofold higher. False high HbF values would be misleading in assessing the effectiveness of hydroxyurea therapy in sickle cell disease patients. We subsequently initiated an examination of the variation in HbF values due to the use of different HbF radial immunodiffusion QUIPlates and different positions within a single plate in an attempt to determine the cause of these discrepancies. Within-run precision studies indicated that significantly different size precipitin rings were obtained depending upon which area of the plate the hemolysate containing antigen (HbF) was applied. A common feature associated with poor precision plates was a marked difference in degree of coloration of gel throughout the plate. Spuriously high HF concentrations were obtained with antigen (HbF) placed in wells located in the lighter colored gel area while antigen placed in wells in the darker colored area of the agarose gel bed were more in agreement with the electrophoretically determined HbF concentrations. The variation in HbF values was significantly greater in the diluted (HbF QUIPlate Diluent) samples than in the neat samples even on plates of uniform gel coloration. As a result of this study, we will continue to monitor high HbF levels by densitometry following alkaline cellulose acetate electrophoresis. PMID:10102137

Schultz, J C

1999-01-01

55

Removal of aqueous Hg(II) and Cr(VI) using phytic acid doped polyaniline/cellulose acetate composite membrane.  

PubMed

Conductive composite membrane-phytic acid (PA) doped polyaniline (PANI)/cellulose acetate (CA) (PANI-PA/CA) was prepared in a simple and environmental-friendly method, in which aniline was blended with CA/PA solution and polymerized before the phase conversion. The resultant composite membranes were characterized by SEM, EDX, FTIR-ATR, BET and electrical resistance measurements. When used as adsorbent for Hg(II) and Cr(VI) ions, the prepared composite membrane exhibits excellent adsorption capability. The adsorption of Hg(II) and Cr(VI) follows a pseudo-second-order kinetic model and best fits the Langmuir isotherm model, with the maximum adsorption capacity reaching 280.11 and 94.34 mg g(-1), respectively. The heavy metal loaded composite membrane can be regenerated and reused after treatment with acid or alkali solution, making it a promising and practical adsorbent for Hg(II) and Cr(VI) removal. Tests with river water were also carried out, indicating good performance and application. PMID:25127386

Li, Renjie; Liu, Lifen; Yang, Fenglin

2014-09-15

56

Nanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations  

E-print Network

silicate SAMH-3 and show that it can be exfoliated using a high shear rate generated by a high-speed mixer to synthesize economically on large scale. Hence, composite/hybrid (`mixed matrix') membranes are widely being materials and a low density of defects. Another approach towards hybrid membran

Nair, Sankar

57

Preparation of sealed tonoplast and plasma-membrane vesicles from Catharanthus roseus (L.) G. Don. cells by free-flow electrophoresis.  

PubMed

Highly purified tonoplast and plasmamembrane vesicles were isolated from microsomes of Catharanthus roseus (L.) G. Don. by preparative free-flow electrophoresis. The relative amounts of tonoplast and plasma-membrane vesicles in the total microsomes varied with the pH of the grinding medium. The most electronegative fractions were identified as tonoplast using nitrate-inhibited, azide-resistant Mg(2+)-ATPase and pyrophosphatase activities as enzyme markers. The least electronegative fractions were identified as plasma membrane using glucan-synthase-II and UDPG:sterolglucosyl-transferase activities as enzyme markers. Other membrane markers, latent inosine-5'-diphosphatase (Golgi), NADPH-cytochrome-c reductase (ER) and cytochrome-c oxidase (mitochondria) were recovered in the fractions intermediate between tonoplast and plasma membrane and did not contaminate either the tonoplast or the plasma-membrane fractions. In the course of searching for a reliable marker for tonoplast, the pyrophosphatase activity was found to be essentially associated with the tonoplast fractions purified by free-flow electrophoresis from C. roseus and other plant materials. The degree of sealing of the tonoplast and plasmamembrane vesicles was probed by their ability to pump protons (measurements of quinacrine quenching) and to generate a membrane potential (absorption spectroscopy of Oxonol VI). A critical evaluation of vesicles sidedness is presented. PMID:24194236

Canut, H; Baudracco, S; Cabané, M; Boudet, A M; Marigo, G

1991-07-01

58

Supported Lipid Bilayer Electrophoresis: A New Paradigm in Membrane Biophysics and Separations  

E-print Network

in this protocol are Tris Buffered Saline (TBS: 10 mM Tris, 100 mM NaCl, pH 7.4) and PBS (10 mM Phosphate Buffer, 150 mM NaCl, pH 7.4). Two ~5 M sucrose solutions were made for this procedure, one with each of the two buffers. Higher concentration sucrose...(hydroxymethyl)aminomethane buffer (10 mM Tris, 100 mM NaCl, pH 7.4, Tris/NaCl buffer) and subjected to ten freeze/thaw cycles in liquid nitrogen and warm water. The solution was extruded ten times through a track-etched polycarbonate membrane with 100 nm pores (Whatman...

Pace, Hudson 1982-

2012-11-28

59

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

60

Membrane flow in plants: Fractionation of growing pollen tubes of tobacco by preparative free-flow electrophoresis and kinetics of labeling of endoplasmic reticulum and golgi apparatus with [ 3 H]leucine  

Microsoft Academic Search

Summary Tobacco (Nicotiana tabacum L.) pollen, germinated 4 hours in suspension culture, was labeled with radioactive leucine and fractionated into constituent membranes by the technique of preparative free-flow electrophoresis. Tubes were ruptured by sonication directly into the electrophoresis buffer. Unfortunately, the Golgi apparatus of the rapidly elongating pollen tubes did not survive the sonication step. However, it was possible to

R. Kappler; U. Kristen; D. J. Morré

1986-01-01

61

Preparation of sealed tonoplast and plasma-membrane vesicles from Catharanthus roseus (L.) G. Don. cells by free-flow electrophoresis  

Microsoft Academic Search

Highly purified tonoplast and plasmamembrane vesicles were isolated from microsomes of Catharanthus roseus (L.) G. Don. by preparative free-flow electrophoresis. The relative amounts of tonoplast and plasma-membrane vesicles in the total microsomes varied with the pH of the grinding medium. The most electronegative fractions were identified as tonoplast using nitrate-inhibited, azide-resistant Mg2+-ATPase and pyrophosphatase activities as enzyme markers. The least

Hervé Canut; Sylvie Baudracco; Mireille Cabané; Alain-Michel Boudet; Gérard Marigo

1991-01-01

62

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)...

63

Coupling sodium dodecyl sulfate-capillary polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry via a poly(tetrafluoroethylene) membrane.  

PubMed

Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) is a fundamental analytical technique for proteomic research, and SDS-capillary gel electrophoresis (CGE) is its miniaturized version. Compared to conventional slab-gel electrophoresis, SDS-CGE has many advantages such as increased separation efficiency, reduced separation time, and automated operation. SDS-CGE is not widely accepted in proteomic research primarily due to the difficulties in identifying the well-resolved proteins. MALDI-TOF-MS is an outstanding platform for protein identifications. Coupling the two would solve the problem but is extremely challenging because the MS detector has no access to the SDS-CGE-resolved proteins and the SDS interferes with MS detection. In this work we introduce an approach to address these issues. We discover that poly(tetrafluoroethylene) (PTFE) membranes are excellent materials for collecting SDS-CGE-separated proteins. We demonstrate that we can wash off the SDS bound to the collected proteins and identify these proteins on-membrane with MALDI-TOF-MS. We also show that we can immunoblot and Coomassie-stain the proteins collected on these membranes. PMID:21309548

Lu, Joann J; Zhu, Zaifang; Wang, Wei; Liu, Shaorong

2011-03-01

64

Controlled porosity osmotic pump-based controlled release systems of pseudoephedrine. I. Cellulose acetate as a semipermeable membrane.  

PubMed

A controlled porosity osmotic pump-based drug delivery system has been described in this study. Unlike the elementary osmotic pump (EOP) which consists of an osmotic core with the drug surrounded by a semipermeable membrane drilled with a delivery orifice, controlled porosity of the membrane is accomplished by the use of different channeling agents in the coating. The usual dose of pseudoephedrine is 60 mg to be taken three or four times daily. It has a short plasma half life of 5-8 h. Hence, pseudoephedrine was chosen as a model drug with an aim to develop a controlled release system for a period of 12 h. Sodium bicarbonate was used as the osmogent. The effect of different ratios of drug:osmogent on the in-vitro release was studied. Cellulose acetate (CA) was used as the semipermeable membrane. Different channeling agents tried were diethylphthalate (DEP), dibutylphthalate (DBP), dibutylsebacate (DBS) and polyethyleneglycol 400 (PEG 400). The effect of polymer loading on in-vitro drug release was studied. It was found that drug release rate increased with the amount of osmogent due to the increased water uptake, and hence increased driving force for drug release. This could be retarded by the proper choice of channeling agent in order to achieve the desired zero order release profile. Also the lag time seen with tablets coated using diethylphthalate as channeling agent was reduced by using a hydrophilic plasticizer like polyethyleneglycol 400 in combination with diethylphthalate. This system was found to deliver pseudoephedrine at a zero order rate for 12 h. The effect of pH on drug release was also studied. The optimized formulations were subjected to stability studies as per ICH guidelines at different temperature and humidity conditions. PMID:12695059

Makhija, Sapna N; Vavia, Pradeep R

2003-04-14

65

Colorful Electrophoresis  

NSDL National Science Digital Library

In this activity, learners follow step-by-step instructions to build a gel electrophoresis chamber using inexpensive materials from local hardware and electronic stores. Then, learners follow instructions to simulate DNA electrophoresis using food colors from the kitchen pantry.

Utah, University O.

2012-01-01

66

Effect of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) upon membrane ionic exchanges in sea urchin eggs  

SciTech Connect

The effect of TPA (12-O-tetradecanoylphorbol-13-acetate) upon ionic exchanges was investigated in eggs of the sea urchin Arbacia lixula. Ouabain-sensitive {sup 86}Rb uptake and amiloride-sensitive {sup 24}Na influx were dramatically stimulated after TPA addition, indicating an enhancement of total ionic permeabilities. Stimulation by TPA of both Na{sup +}/H{sup +} and Na{sup +}/K{sup +} exchanges was canceled by amiloride, suggesting that activation of protein kinase C elicits, via Na{sup +}/H{sup +} activity, stimulation of the sodium pump. However, TPA did not stimulate sodium pump activity and Na{sup +}/H{sup +} exchange at the same rate as fertilization, probably because of an absence of calcium-dependent events. Further fertilization of TPA pretreated eggs triggered an enhancement of sodium pump activity when the TPA treatment duration did not exceed 10 minutes. It is suggested that TPA activates preexisting transporting mechanisms in plasma membranes of unfertilized eggs (Na{sup +} stat, pH stat).

Ciapa, B.; Payan, P. (UA 651 Centre National de la Recherche Scientifique, Nice (France)); Allemand, D. (Centre Scientifique de Monaco, Monte Carlo (Monaco))

1989-12-01

67

A proteomic approach based on peptide affinity chromatography, 2-dimensional electrophoresis and mass spectrometry to identify multiprotein complexes interacting with membrane-bound receptors  

PubMed Central

There is accumulating evidence that membrane-bound receptors interact with many intracellular proteins. Multiprotein complexes associated with ionotropic receptors have been extensively characterized, but the identification of proteins interacting with G protein-coupled receptors (GPCRs) has so far only been achieved in a piecemeal fashion, focusing on one or two protein species. We describe a method based on peptide affinity chromatography, two-dimensional electrophoresis, mass spectrometry and immunoblotting to identify the components of multiprotein complexes interacting directly or indirectly with intracellular domains of GPCRs or, more generally, any other membrane-bound receptor. Using this global approach, we have characterized multiprotein complexes that bind to the carboxy-terminal tail of the 5-hydroxytryptamine type 2C receptor and are important for its subcellular localization in CNS cells (Bécamel et al., EMBO J., 21(10): 2332, 2002). PMID:12734563

Bécamel, Carine; Galéotti, Nathalie; Poncet, Joël; Jouin, Patrick; Dumuis, Aline; Bockaert, Joël

2002-01-01

68

Influence of acetic, citric, and lactic acids on Escherichia coli O157:H7 membrane lipid composition, verotoxin secretion, and acid resistance in simulated gastric fluid.  

PubMed

The effect of organic acid (acetic, citric, and lactic acids) adaptation at equivalent initial pH values (6.4 and 5.4) on changes in membrane lipid composition, verotoxin concentration, and acid resistance in simulated gastric fluid (pH 1.5, 37 degrees C) was determined for Escherichia coli O157:H7 ATCC 43895 (HEC) and an rpoS mutant of E. coli O157:H7 ATCC 43895 (RM, FRIK 816-3). For HEC, lactic acid-adapted (pH 5.4) cells had the greatest D-value (32.2 min) and acetic acid-adapted (pH 5.4) cells had the smallest D-value (16.6 min) in simulated gastric fluid. For RM, D-values of citric and acetic acid-adapted cells were similar to those for nonadapted cells grown at pH 7.3, but D-values increased from 13.1 to 27.9 min in lactic acid-adapted cells (from pH 7.3 to pH 5.4). For both strains, the ratio of cis-vaccenic to palmitic acids decreased for citric and lactic acid-adapted cells, but the ratio increased for acetic acid-adapted cells at pH 5.4. Organic acid-adapted cells produced less total verotoxin than did nonadapted cells at approximately 10(8) CFU/ml. Extracellular verotoxin concentration proportionally decreased with decreasing pH for both HEC and RM. Changes in membrane lipid composition, verotoxin concentration, and acid resistance in HEC and RM were dependent on both pH and organic acid. Deletion of the rpoS gene did not affect these changes but did decrease acid resistance in citric acid-adapted cells. Results indicate that decreased membrane fluidity may have caused increased acid resistance and decreased verotoxin secretion. PMID:15830655

Yuk, Hyun-Gyun; Marshall, Douglas L

2005-04-01

69

Electrophoresis-Enhanced Detection of Deoxyribonucleic Acids on a Membrane-Based Lateral Flow Strip Using Avian Influenza H5 Genetic Sequence as the Model  

PubMed Central

This study reports a simple strategy to detect a deoxyribonucleic acid (DNA) on a membrane-based lateral flow (MBLF) strip without tedious gel preparation, gel electrophoresis, and EtBr-staining processes. The method also enhances the detection signal of the genetic sample. A direct electric field was applied over two ends of the MBLF strips to induce an electrophoresis of DNAs through the strips. The signal enhancement was demonstrated by the detection of the H5 subtype of avian influenza virus (H5 AIV). This approach showed an excellent selectivity of H5 AIV from other two control species, Arabidopsis thaliana and human PSMA5. It also showed an effective signal repeatability and sensitivity over a series of analyte concentrations. Its detection limit could be enhanced, from 40 ng to 0.1 ng by applying 12 V. The nano-gold particles for the color development were labeled on the capture antibody, and UV-VIS and TEM were used to check if the labeling was successful. This detection strategy could be further developed to apply on the detection of drug-allergic genes at clinics or detection of infectious substances at incident sites by a simple manipulation with an aid of a mini-PCR machine and auxiliary kits. PMID:24603637

Wu, Jui-Chuang; Chen, Chih-Hung; Fu, Ja-Wei; Yang, Huan-Ching

2014-01-01

70

Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air.  

PubMed

The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the ?g m(-3) range) and their variations with sampling site and time. In this work, a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE), a quick separation technique that requires nothing more than some nanoliters of sample and, when combined with capacitively coupled contactless conductometric detection (C(4)D), is particularly favorable for ionic species that do not absorb in the UV-vis region, like the target analytes formaldehyde, formic acid, acetic acid and ammonium. The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry's constant such as formaldehyde and carboxylic acids, or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8.3 nL s(-1)), while the sample was aspirated through the annular gap of the concentric tubes at 2.5 mL s(-1). A second unit, in all similar to the CMDS, was operated as a capillary membrane diffusion emitter (CMDE), generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS. The fluids of the system were driven with inexpensive aquarium air pumps, and the collected samples were stored in vials cooled by a Peltier element. Complete protocols were developed for the analysis, in air, of NH(3), CH(3)COOH, HCOOH and, with a derivatization setup, CH(2)O, by associating the CMDS collection with the determination by CE-C(4)D. The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot's reaction. Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction, solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW). All techniques and methods of this work are in line with the green analytical chemistry trends. PMID:21035648

Coelho, Lúcia H G; Melchert, Wanessa R; Rocha, Flavio R; Rocha, Fábio R P; Gutz, Ivano G R

2010-11-15

71

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

72

A simple technique to improve the resolution of membrane acidic proteins of the haloarchaeon Haloferax volcanii by 2D electrophoresis.  

PubMed

Proteins present in the archaeal cell envelope play key roles in a variety of processes necessary for survival in extreme environments. The haloarchaeon Haloferax volcanii is a good model for membrane proteomic studies because its genome sequence is known, it can be genetically manipulated, and a number of studies at the "omics" level have been performed in this organism. This work reports an easy strategy to improve the resolution of acidic membrane proteins from H. volcanii by 2DE. The method is based on the solubilization, delipidation, and salt removal from membrane proteins. Due to the abundance of the S-layer glycoprotein (SLG) in membrane protein extracts, other proteins from the envelope are consequently underrepresented. Thus, a protocol to reduce the amount of the SLG by EDTA treatment was applied and 11 cm narrow range pH (3.9-5.1) IPG strips were used to fractionate the remaining proteins. Using this method, horizontal streaking was substantially decreased and at least 75 defined spots (20% of the predicted membrane proteome within this pI/Mw range) were reproducibly detected. Two of these spots were identified as thermosome subunit 1 and NADH dehydrogenase from H. volcanii, confirming that proteins from the membrane fraction were enriched. Removal of the SLG from membrane protein extracts can be applied to increase protein load for 2DE as well as for other proteomic methods. PMID:25224925

Paggi, Roberto A; Giménez, María Inés; De Castro, Rosana E; Cesari, Andreina

2014-12-01

73

STABILITY OF MFI ZEOLITE-FILLED PDMS MEMBRANES DURING PERVAPORATIVE ETHANOL RECOVERY FROM AQUEOUS MIXTURES CONTAINING ACETIC ACID  

EPA Science Inventory

Pervaporation is a potential process for recovering bioethanol produced from biomass fermentation. Fermentation broths contain ethanol, water, and a variety of other compounds, often including carboxylic acids. The effects of acetic acid on long-term pervaporation of aqueous et...

74

Toxic metal ion separation by cellulose acetate/sulfonated poly(ether imide) blend membranes: effect of polymer composition and additive.  

PubMed

Toxic heavy metal ion removal from industrial effluents are gaining increased visibility owing to environmental concern and saving precious materials. In this work, an attempt has been made to remove the valuable metal ions using modified ultrafiltration (UF) blend membranes based on cellulose acetate (CA) and sulfonated poly(ether imide) (SPEI) were prepared in the presence and absence of additive, poly(ethylene glycol) 600 (PEG600) in various compositions. Prepared membranes were characterized in terms of pure water flux (PWF), water content and membrane hydraulic resistance. High flux UF membranes were obtained in the range of 15-25 wt% SPEI and 2.5-10 wt% PEG600 in the polymer blend. The molecular weight cut-off (MWCO) of the blend membranes were determined using protein separation studies found to vary from 20 to greater than 69 kDa. Surface morphology of the blend membranes were analysed with scanning electron microscopy. Studies were carried out to find the rejection and permeate flux of metal ions such as Cu(II), Ni(II), Zn(II) and Cd(II) using polyethyleneimine as the chelating ligand. On increasing the composition of SPEI and PEG600, the rejection of metal ions is decreasing while the permeate flux has an increasing trend. These effects are due to the increased pore formation in the CA/SPEI blend membranes because of the hydrophilic SPEI and polymeric additive PEG600. In general, it was found that CA/SPEI blend membranes displayed higher permeate flux and lower rejection compared to pure CA membranes. The extent of separation of metal ions depends on the affinity of metal ions to polyethyleneimine to form macromolecular complexes and the stability of the formed complexes. PMID:18191025

Nagendran, A; Vijayalakshmi, A; Arockiasamy, D Lawrence; Shobana, K H; Mohan, D

2008-07-15

75

Analysis of electrophoresis performance  

NASA Technical Reports Server (NTRS)

The SAMPLE computer code models electrophoresis separation in a wide range of conditions. Results are included for steady three dimensional continuous flow electrophoresis (CFE), time dependent gel and acetate film experiments in one or two dimensions and isoelectric focusing in one dimension. The code evolves N two dimensional radical concentration distributions in time, or distance down a CFE chamber. For each time or distance increment, there are six stages, successively obtaining the pH distribution, the corresponding degrees of ionization for each radical, the conductivity, the electric field and current distribution, and the flux components in each direction for each separate radical. The final stage is to update the radical concentrations. The model formulation for ion motion in an electric field ignores activity effects, and is valid only for low concentrations; for larger concentrations the conductivity is, therefore, also invalid.

Roberts, G. O.

1984-01-01

76

Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.  

PubMed

In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 ?L of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples. PMID:22098933

Li, Pingjing; Zhang, Xing; Hu, Bin

2011-12-30

77

Synthesis and Characterisation of ETS-10/Acetate-based Ionic Liquid/Chitosan Mixed Matrix Membranes for CO2/N2 Permeation  

PubMed Central

Mixed matrix membranes (MMMs) were prepared by incorporating organic surfactant-free hydrothermally synthesised ETS-10 and 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) to chitosan (CS) polymer matrix. The membrane material characteristics and permselectivity performance of the two-component membranes were compared with the three-component membrane and the pure CS membrane. The addition of IL increased CO2 solubility of the polymer, and, thus, the CO2 affinity was maintained for the MMMs, which can be correlated with the crystallinity, measured by FT-IR, and void fraction calculations from differences between theoretical and experimental densities. The mechanical resistance was enhanced by the ETS-10 nanoparticles, and flexibility decreased in the two-component ETS-10/CS MMMs, but the flexibility imparted by the IL remained in three-component ETS-10/IL/CS MMMs. The results of this work provide insight into another way of facing the adhesion challenge in MMMs and obtain CO2 selective MMMs from renewable or green chemistry materials. PMID:24957178

Casado-Coterillo, Clara; López-Guerrero, María del Mar; Irabien, Ángel

2014-01-01

78

Gel Electrophoresis  

NSDL National Science Digital Library

This interactive activity from the Dolan DNA Learning Center illustrates the process of gel electrophoresis, in which DNA fragments are separated by size as they migrate at different rates through a gel matrix.

Foundation, Wgbh E.

2007-04-19

79

Membrane filtration of Sudan orange G on a cellulose acetate membrane filter for separation-preconcentration and spectrophotometric determination in water, chili powder, chili sauce and tomato sauce samples.  

PubMed

A simple membrane filtration procedure for separation-enrichment of Sudan orange G is presented. The method is based on the adsorption of Sudan orange G on a cellulose acetate filter and its elution from the membrane with 10 mL of ethanol. Sudan orange G in the eluent was determined by UV-visible spectrophotometry at 388 nm. The effect of analytical conditions, including pH, flow rates and eluent, sample volume, type of membrane for quantitative preconcentration and separation of Sudan orange G were examined. The influences of matrix components on Sudan orange G recoveries were studied. The preconcentration factor was 125. The detection limit was 4.9 ?g L(-1). The relative standard deviation was 4.3%. The presented procedure was applied to chili powder, chili sauce, tomato sauce, powdered beverage and water samples. PMID:22617351

ALOthman, Zeid A; Unsal, Yunus E; Habila, Mohamed; Shabaka, Azza; Tuzen, Mustafa; Soylak, Mustafa

2012-08-01

80

Formation of membranes by means of immersion precipitation : Part II. the mechanism of formation of membranes prepared from the system cellulose acetate-acetone-water  

Microsoft Academic Search

Using equations and boundary conditions derived in Part I1, calculations have been performed on the ternary diffusion processes that occur in a cellulose acetate (CA) -acetone casting solution immersed into a water bath. The necessary concentration-dependent thermodynamic and hydrodynamic parameters have been derived from experimental data on the three limiting binary mixtures. Calculations show that immersion of the polymer solution

A. J. Reuvers; C. A. Smolders

1987-01-01

81

Electrophoresis technology  

NASA Technical Reports Server (NTRS)

A new high resolution apparatus designed for space was built as a laboratory prototype. Using a moving wall with a low zeta potential coating, the major sources of flow distortion for an electrophoretic sample stream are removed. Highly resolved fractions, however, will only be produced in space because of the sensitivity of this chamber to buoyancy-induced convection in the laboratory. The second and third flights of the McDonnell Douglas Astronautics Corporation continuous flow electrophoresis system carried samples developed at MSFC intended to evaluate the broad capabilities of free flow electrophoresis in a reduced gravity environment. Biological model materials, hemoglobin and polystyrene latex microspheres, were selected because of their past use as electrophoresis standards and as visible markers for fluid flow due to electroosmosis, spacecraft acceleration or other factors. The dependence of the separation resolution on the properties of the sample and its suspension solution was assessed.

Snyder, R. S.

1985-01-01

82

Characterization of a direct effect of phorbol myristate acetate on human neutrophil cell membrane using 31D8 monoclonal antibody  

Microsoft Academic Search

We found that 4-13-phorbol 12-myristate 13-acetate (PMA) caused decreased expression of the polymorphonuclear neutrophil (PMN) surface antigen 31D8. In contrast to the rapid initiation of the oxidative burst caused by PMA, the effect was slow to start but in- creased during incubation periods up to 50 mm. To study this apparent protein kinase C-independent late effect of PMA, we measured

Charles L. Woronick; Eufronio G. MaderazotS; Monique N. AnthonyPeter; J. Krause; Ramadan I. Sha

83

Parallel characterization of anaerobic toluene- and ethylbenzene-degrading microbial consortia by PCR-denaturing gradient gel electrophoresis, RNA-DNA membrane hybridization, and DNA microarray technology  

NASA Technical Reports Server (NTRS)

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

84

Gel Electrophoresis  

NSDL National Science Digital Library

In this activity, learners simulate the process of DNA fingerprinting by using electricity to separate colored dyes. Learners use simple materials to assemble a comb (electrophoresis chamber) to hold the samples, make a 0.2% sodium bicarbonate buffer and 1% gel solution, connect a high voltage power supply, and prepare 5 different samples. Then learners test their model and observe each sample.

Yu, Julie

2007-01-01

85

Proton-transport activity, sidedness, and morphometry of tonoplast and plasma-membrane vesicles purified by free-flow electrophoresis from roots of Lepidium sativum L. and hypocotyls of Cucurbita pepo L  

Microsoft Academic Search

Large-scale preparations of highly purified tonoplast and plasma-membrane vesicles were obtained from roots (garden cress, Lepidium sativum L.) and shoots (etiolated zucchini hypocotyl, Cucurbita pepo L.) of representative dicotyledonous seedlings. When tonoplast-enriched fractions of cress roots were prepared by centrifugation and then subjected to free-flow electrophoresis a highly purified tonoplast fraction was obtained. This fraction from cress roots was characterized

Günther F. E. Scherer; Barbara Dorp; Claudia Schöllmann; Dieter Volkmann

1992-01-01

86

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

87

STABILITY OF MFI ZEOLITE-FILLED PDMS MEMBRANES DURING PERVAPORATIVE ETHANOL RECOVERY FROM AQUEOUS MIXTURES CONTAINING ACETIC ACID  

EPA Science Inventory

Pervaporation is potentially a cost-effective means of recovering biofuels, such as ethanol, from biomass fermentation broths for small- to medium-scale applications (~2 - 20 million liters per year). Hydrophobic zeolite-filled polydimethylsiloxane (PDMS) membranes have been sho...

88

Fluid flow electrophoresis in space  

NASA Technical Reports Server (NTRS)

Four areas relating to free-flow electrophoresis in space were investigated. The first was the degree of improvement over earthbound operations that might be expected. The second area of investigation covered the problems in developing a flowing buffer electrophoresis apparatus. The third area of investigation was the problem of testing on the ground equipment designed for use in space. The fourth area of investigation was the improvement to be expected in space for purification of biologicals. The results of some ground-based experiments are described. Other studies included cooling requirements in space, fluid sealing techniques, and measurement of voltage drop across membranes.

Griffin, R. N.

1975-01-01

89

5,6-Dimethylxanthenone-4-acetic Acid (DMXAA) Activates Stimulator of Interferon Gene (STING)-dependent Innate Immune Pathways and Is Regulated by Mitochondrial Membrane Potential*  

PubMed Central

The chemotherapeutic agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA) is a potent inducer of type I IFNs and other cytokines. This ability is essential for its chemotherapeutic benefit in a mouse cancer model and suggests that it might also be useful as an antiviral agent. However, the mechanism underlying DMXAA-induced type I IFNs, including the host proteins involved, remains unclear. Recently, it was reported that the antioxidant N-acetylcysteine (NAC) decreased DMXAA-induced TNF-? and IL-6, suggesting that oxidative stress may play a role. The goal of this study was to identify host proteins involved in DMXAA-dependent signaling and determine how antioxidants modulate this response. We found that expression of IFN-? in response to DMXAA in mouse macrophages requires the mitochondrial and endoplasmic reticulum resident protein STING. Addition of the antioxidant diphenylene iodonium (DPI) diminished DMXAA-induced IFN-?, but this decrease was independent of both the NADPH oxidase, Nox2, and de novo generation of reactive oxygen species. Additionally, IFN-? up-regulation by DMXAA was inhibited by agents that target the mitochondrial electron transport chain and, conversely, loss of mitochondrial membrane potential correlated with diminished innate immune signaling in response to DMXAA. Up-regulation of Ifnb1 gene expression mediated by cyclic dinucleotides was also impaired by DPI, whereas up-regulation of Ifnb1 mRNA due to cytosolic double-stranded DNA was not. Although both stimuli signal through STING, cyclic dinucleotides interact directly with STING, suggesting that recognition of DMXAA by STING may also be mediated by direct interaction. PMID:23027866

Prantner, Daniel; Perkins, Darren J.; Lai, Wendy; Williams, Mark S.; Sharma, Shruti; Fitzgerald, Katherine A.; Vogel, Stefanie N.

2012-01-01

90

Electrophoresis device  

NASA Technical Reports Server (NTRS)

A device for separating cellular particles of a sample substance into fractionated streams of different cellular species includes a casing having a distribution chamber, a separation chamber, and a collection chamber. The electrode chambers are separated from the separation chamber interior by means of passages such that flow variations and membrane variations around the slotted portion of the electrode chamber do not enduce flow perturbations into the laminar buffer curtain flowing in the separation chamber. The cellular particles of the sample are separated under the influence of the electrical field and the separation chamber into streams of different cellular species. The streams of separated cells enter a partition array in the collection chamber where they are fractionated and collected.

Rhodes, P. H.; Snyder, R. S. (inventors)

1982-01-01

91

Kidney cell electrophoresis  

NASA Technical Reports Server (NTRS)

A kidney cell electrophoresis technique is described in four parts: (1) the development and testing of electrophoresis solutions; (2) optimization of freezing and thawing; (3) procedures for evaluation of separated kidney cells; and (4) electrophoretic mobility characteristics of kidney cells.

Todd, P.

1979-01-01

92

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. PMID:21265514

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

2011-01-01

93

Zone Electrophoresis of Human Parotid Saliva in Acrylamide Gel  

Microsoft Academic Search

THE zone electrophoresis of human parotid saliva proteins has been carried out with a variety of supporting media, including filter paper, cellulose acetate, agar gel and starch gel, with separations usually of from five to twelve fractions1-8. In a comparative investigation of these media, D'Silva and Ferguson7 obtained their most satisfactory results with a combination of cellulose acetate and starch

T. S. Meyer; B. L. Lamberts

1965-01-01

94

Kidney Cell Electrophoresis  

NASA Technical Reports Server (NTRS)

Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated, ground support in the form of analytical cell electrophoresis and flow cytometry was provided and cells returned from space flight were analyzed. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. The protocol established and utilized is given.

Todd, P.

1985-01-01

95

Investigation of unique interactions between cellulose acetate and ionic liquid [EMIM]SCN, and their influences on hollow fiber ultrafiltration membranes  

Microsoft Academic Search

This study investigates the molecular interactions between ionic liquid, 1-ethyl-3-methylimidazolium thiocyanate ([EMIM]SCN) and cellulose acetate (CA), employing not only experimental characterizations including FTIR and rheological tests, but also molecular dynamics simulations. Due to the electrostatic nature of ionic liquids, [EMIM]SCN interacts intensely with CA molecules through pronounced hydrogen bonding, Coulombic forces and van der Waals interactions, which play an important

Ding Yu Xing; Na Peng; Tai-Shung Chung

2011-01-01

96

ProteinAnalysis Electrophoresis  

E-print Network

ProteinDetectionKit(Colorimetric)--GLYCO-PRO GoldSolution,Colloidal--50755 OilRedO--O9755 PonceauSSolution--P7170 ProteoSilverTM--PROT-SIL1 ProteoSilver (G 1041). #12;ProteinAnalysis Electrophoresis sigma-aldrich.com 104 ELECTROPHORESIS Silver Stain Markers Designed for molecular weight determinations on silver stained gels, Silver Stain SDS

Lebendiker, Mario

97

Automatic multiple applicator electrophoresis  

NASA Technical Reports Server (NTRS)

Easy-to-use, economical device permits electrophoresis on all known supporting media. System includes automatic multiple-sample applicator, sample holder, and electrophoresis apparatus. System has potential applicability to fields of taxonomy, immunology, and genetics. Apparatus is also used for electrofocusing.

Grunbaum, B. W.

1977-01-01

98

Electrophoresis of biological materials  

NASA Technical Reports Server (NTRS)

The selection of biological products was studied for electrophoresis in space. Free flow electrophoresis, isoelectric focusing, and isotachophoresis are described. The candidates discussed include: immunoglobulins and gamma globulins; isolated islet of langerhans from pancreas; bone marrow; tumor cells; kidney cells, cryoprecipitate; and column separated cultures.

1975-01-01

99

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

100

Electrophoresis and Gel Analysis  

NSDL National Science Digital Library

In this animation produced by WGBH and Digizyme, Inc., see how molecules of DNA are separated using gel electrophoresis, and how this process enables scientists to compare the molecular variations of two or more DNA samples.

2011-08-05

101

Gel Electrophoresis of Dyes  

NSDL National Science Digital Library

In this experiment related to plant biotechnology, learners discover how to prepare and load an electrophoresis gel. They will then run the gels in an electrophoresis system to separate several dyes that are of different molecular sizes and carry different charges. This technique is fundamental to many of the procedures used in biotechnology. This lesson guide includes background information for the educator, safety precautions, and questions with answers for learners. For safety reasons, adult supervision is recommended. Modifications for use with younger learners are described in a related PDF (see related resource).

Stephens, Janice; Leach, Jan

2011-01-01

102

Fraction collector for electrophoresis  

NASA Technical Reports Server (NTRS)

Rotating-tube electrophoresis apparatus employs rotating jet of eluting buffer to reduce effects of convection during separation. Designed for separation of microorganisms and biological species, system combines gravity/gradient compensating of lumen with buffer flush at fraction outlet to increase separation efficiency.

Bier, M.

1977-01-01

103

Free-solution electrophoresis of proteins in an improved density gradient column and by capillary electrophoresis  

Microsoft Academic Search

The electrophoretic mobilities of bovine serum albumin, ?-lactoglobulin A and B, ?-lactalbumin and myoglobin were measured in free solution using an improved version of the Boltz-Todd vertical density-gradient electrophoresis column. Dialysis membranes were used for the isolation of the side-arm electrodes from the column and large-volume electrode containers were connected to each other by a circulating buffer loop. The improvements

K. D. Cole; P. Todd; K. Srinivasan; B. K. Dutta

1995-01-01

104

Happy bicentennial, electrophoresis!  

PubMed

A short survey of electrophoresis and a celebration of its bicentennial, with some remarkable mementos and a list of books that shaped the field. Where one also learns of a secret production plant with a huge-scale electrophoretic apparatus for skimming of latex from Hevea brasiliensis and keeping the wheels of the Ally Army running during World War II. And of cyber (mammoth) 2D gels of 1.5 x 1 m in size accommodating >12,000 spots. PMID:19938305

Righetti, Pier Giorgio

2009-12-01

105

Detection of Polymorphisms of Human DNA by Gel Electrophoresis as Single-Strand Conformation Polymorphisms  

Microsoft Academic Search

We 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

Masato Orita; Hiroyuki Iwahana; Hiroshi Kanazawa; Kenshi Hayashi; Takao Sekiya

1989-01-01

106

Preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting a mixture of hydrogen and ketene with a heterogeneous catalyst containing a transition metal to produce acetaldehyde, which is then reacted with ketene in the presence of an acid catalyst to produce vinyl acetate.

Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

1998-01-01

107

Electrooxidation of tigogenin acetate  

Microsoft Academic Search

Electrooxidation of tigogenin acetate afforded two products: 3?-acetoxy-16?-hydroxy-23,24-dinor-5?-cholanoic acid lactone (2) and 20-epitigogenin acetate (3). The structure of the latter compound was confirmed by an X-ray analysis. The tentative mechanism of reaction is proposed.

Jacek W. Morzycki; Yliana López; Jolanta P?oszy?ska; Rosa Santillan; Leszek Siergiejczyk; Andrzej Sobkowiak

2007-01-01

108

Protein content and enzyme activities in methanol- and acetate-grown Methanosarcina thermophila  

SciTech Connect

The cell extract protein content of acetate-and methanol-grown Methanosarcina thermophila TM-1 was examined by two-dimensional polyacrylamide gel electrophoresis. More than 100 mutually exclusive spots were present in acetate- and methanol-grown cells. Spots corresponding to acetate kinase, phosphotransacetylase, and the five subunits of the carbon monoxide dehydrogenase complex were identified in acetate-grown cells. Activities for formylmethanofuran dehydrogenase, formylmethanofurn:tetrahydromethanopterin formyl-transferase, 5,10-methenyltetrahydromethanopterin cyclohydrolase, methylene tetrahydromethanopterin:co-enzyme F{sub 420} oxidoreductase, formate dehydrogenase, and carbonic anhydrase were examined in acetate- and methanol-grown Methanosarcina thermophila. Levels of formyltransferase in either acetate- or methanol-grown Methanosarcina thermophila were approximately half the levels detected in H{sub 2}-CO{sub 2}-grown Methanobacterium thermoautotrophicum. All other enzyme activities were significantly lower in acetate- and methanol-grown Methanosarcina thermophila.

Jablonski, P.E.; Cabell, M.C.; Ferry, J.G. (Virginia Polytechnic Institute and State Univ., Blacksburg (USA)); DiMarco, A.A.; Bobik, T.A. (Univ. of Illinois Urbana-Champaign (USA))

1990-03-01

109

Mass Estimation of Native Proteins by Blue Native Electrophoresis  

PubMed Central

Blue native electrophoresis is one of the most popular techniques for mass estimation of native membrane proteins, but the use of non-optimal mass markers and acrylamide gels can compromise accuracy and reliability of the results. We present short protocols taking 10–30 min to prepare optimal sets of membrane protein markers from chicken, rat, mouse, and bovine heart. Especially heart materials from local supermarkets or butcher's shops, e.g. chicken or bovine heart, are ideal sources of high mass membrane protein standards. Considerable discrepancies between the migration behavior of membrane and soluble markers suggest using membrane protein markers for mass estimation of membrane proteins. Soluble standard proteins can be used, with some limitations, when soluble proteins are the focus. Principles and general rules for the determination of mass and oligomeric state of native membrane and soluble proteins are elaborated, and potential pitfalls are discussed. PMID:20173216

Wittig, Ilka; Beckhaus, Tobias; Wumaier, Zibiernisha; Karas, Michael; Schägger, Hermann

2010-01-01

110

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

111

The Acetate Switch  

PubMed Central

To succeed, many cells must alternate between life-styles that permit rapid growth in the presence of abundant nutrients and ones that enhance survival in the absence of those nutrients. One such change in life-style, the “acetate switch,” occurs as cells deplete their environment of acetate-producing carbon sources and begin to rely on their ability to scavenge for acetate. This review explains why, when, and how cells excrete or dissimilate acetate. The central components of the “switch” (phosphotransacetylase [PTA], acetate kinase [ACK], and AMP-forming acetyl coenzyme A synthetase [AMP-ACS]) and the behavior of cells that lack these components are introduced. Acetyl phosphate (acetyl?P), the high-energy intermediate of acetate dissimilation, is discussed, and conditions that influence its intracellular concentration are described. Evidence is provided that acetyl?P influences cellular processes from organelle biogenesis to cell cycle regulation and from biofilm development to pathogenesis. The merits of each mechanism proposed to explain the interaction of acetyl?P with two-component signal transduction pathways are addressed. A short list of enzymes that generate acetyl?P by PTA-ACKA-independent mechanisms is introduced and discussed briefly. Attention is then directed to the mechanisms used by cells to “flip the switch,” the induction and activation of the acetate-scavenging AMP-ACS. First, evidence is presented that nucleoid proteins orchestrate a progression of distinct nucleoprotein complexes to ensure proper transcription of its gene. Next, the way in which cells regulate AMP-ACS activity through reversible acetylation is described. Finally, the “acetate switch” as it exists in selected eubacteria, archaea, and eukaryotes, including humans, is described. PMID:15755952

Wolfe, Alan J.

2005-01-01

112

Static continuous electrophoresis device  

NASA Technical Reports Server (NTRS)

An apparatus is disclosed for carrying out a moving wall type electrophoresis process for separation of cellular particles. The apparatus includes a water-tight housing containing an electrolytic buffer solution. A separation chamber in the housing is defined by spaced opposed moving walls and spaced opposed side walls. Substrate assemblies, which support the moving wall include vacuum ports for positively sealing the moving walls against the substrate walls. Several suction conduits communicate with the suction ports and are arranged in the form of valleys in a grid plate. The raised land portion of the grid plat supports the substrate walls against deformation inwardly under suction. A cooling chamber is carried on the back side of plate. The apparatus also has tensioner means including roller and adjustment screws for maintaining the belts in position and a drive arrangement including an electric motor with a gear affixed to its output shaft. Electrode assemblies are disposed to provide the required electric field.

Rhodes, P. H. (inventor)

1982-01-01

113

Electrophoresis experiment for space  

NASA Technical Reports Server (NTRS)

The Apollo 16 electrophoresis experiment was analyzed, demonstrating that the separation of the two different-size monodisperse latexes did indeed take place, but that the separation was obscured by the pronounced electroosmotic flow of the liquid medium. The results of this experiment, however, were dramatic since it is impossible to carry out a similar separation on earth. It can be stated unequivocally from this experiment that any electrophoretic separation will be enhanced under microgravity conditions. The only question is the degree of this enhancement, which can be expected to vary from one experimental technique to another. The low-electroosmotic-mobility coating (Z6040-MC) developed under this program was found to be suitable for a free-fluid electrophoretic separation such as the experiment designed for the ASTP flight. The problem with this coating, however, is that its permanency is limited because of the slow desorption of the methylcellulose from the coated surface.

Vanderhoff, J. W.; Micale, F. J.

1976-01-01

114

Electrophoresis demonstration on Apollo 16  

NASA Technical Reports Server (NTRS)

Free fluid electrophoresis, a process used to separate particulate species according to surface charge, size, or shape was suggested as a promising technique to utilize the near zero gravity condition of space. Fluid electrophoresis on earth is disturbed by gravity-induced thermal convection and sedimentation. An apparatus was developed to demonstrate the principle and possible problems of electrophoresis on Apollo 14 and the separation boundary between red and blue dye was photographed in space. The basic operating elements of the Apollo 14 unit were used for a second flight demonstration on Apollo 16. Polystyrene latex particles of two different sizes were used to simulate the electrophoresis of large biological particles. The particle bands in space were extremely stable compared to ground operation because convection in the fluid was negligible. Electrophoresis of the polystyrene latex particle groups according to size was accomplished although electro-osmosis in the flight apparatus prevented the clear separation of two particle bands.

Snyder, R. S.

1972-01-01

115

Kidney cell electrophoresis, continuing task  

NASA Technical Reports Server (NTRS)

Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated to provide ground support in the form of analytical cell electrophoresis and flow cytometry. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. Cells were prepared in suspension prior to flight in electrophoresis buffer and 10% calf serum. Electrophoretic separation proceeded in electrophoresis buffer without serum in the Continuous Flow Electrophoretic Separator, and fractions were collected into sample bags containing culture medium and concentrated serum. Fractions that yielded enough progeny cells were analyzed for morphology and electrophoretic mobility distributions. It is noted that the lowest mobility fraction studied produced higher mobility progeny while the other fractions produced progeny cells with mobilities related to the fractions from which they were collected.

Todd, P. W.

1985-01-01

116

Binary Oscillatory Crossflow Electrophoresis  

NASA Technical Reports Server (NTRS)

Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that solute is drawn into the cell from reservoirs at both ends of the cell leading to a large mass build up. As a consequence, any initially induced mass flux will vanish after short times. This effect was not captured by the infinite channel model and hence numerical and experimental results deviated significantly. The revised model including finite cell lengths and reservoir volumes allowed quantitative predictions of the time history of the concentration profile throughout the system. This latter model accurately describes the fluxes observed for both oscillatory flow modes in experiments using single protein species. Based on the results obtained from research funded under NASA grant NAG-8-1080.S, we conclude that binary separations are not possible using purely oscillatory flow modes because of end effects associated with the cos((omega)t) mode. Our research shows, however, that a combination of cos(2(omega)t) and steady flow should lead to efficient separation free of end effects. This possibility is currently under investigation.

Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

1997-01-01

117

Methane from acetate.  

PubMed Central

The general features are known for the pathway by which most methane is produced in nature. All acetate-utilizing methanogenic microorganisms contain CODH which catalyzes the cleavage of acetyl-CoA; however, the pathway differs from all other acetate-utilizing anaerobes in that the methyl group is reduced to methane with electrons derived from oxidation of the carbonyl group of acetyl-CoA to CO2. The current understanding of the methanogenic fermentation of acetate provides impressions of nature's novel solutions to problems of methyl transfer, electron transport, and energy conservation. The pathway is now at a level of understanding that will permit productive investigations of these and other interesting questions in the near future. PMID:1512186

Ferry, J G

1992-01-01

118

Copolymers For Capillary Gel Electrophoresis  

DOEpatents

This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

Liu, Changsheng (State College, PA); Li, Qingbo (State College, PA)

2005-08-09

119

Alpha naphthyl acetate esterase in human blood cells with different molecular weights  

Microsoft Academic Search

Normal human blood cells contain esterases which hydrolyze a-naphthyl acetate (aNA). Purified preparations of these cells were investigated by polyacrylamide gradient gel electrophoresis at pH 9.0 and subsequent staining of gels for esterase activity. Extractable aNA esterase was separated according to molecular weight.

J. Oertel; R. Wirthmüller; M. Kastner

1983-01-01

120

Antibody enhancement of free-flow electrophoresis  

NASA Technical Reports Server (NTRS)

Specific T cell clones and antibodies (ABs) were developed to study the efficiency of purifying closely associated T cells using Continuous Flow Electrophoresis System. Enhanced separation is accomplished by tagging cells first with ABs directed against the antigenic determinants on the cell surface and then with ABs against the Fc portion of the first AB. This second AB protrudes sufficiently beyond the cell membrane and glycocalyx to become the major overall cell surface potential determinant and thus causes a reduction of electrophoretic mobility. This project was divided into three phases. Phase one included development of specific T cell clones and separation of these specific clones. Phase two extends these principles to the separation of T cells from spleen cells and immunized lymph node cells. Phase three applies this double antibody technique to the separation of T cytotoxic cells from bone marrow.

Cohly, H. H. P.; Morrison, Dennis R.; Atassi, M. Zouhair

1988-01-01

121

Overview on mechanisms of acetic acid resistance in acetic acid bacteria.  

PubMed

Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided. PMID:25575804

Wang, Bin; Shao, Yanchun; Chen, Fusheng

2015-02-01

122

Proteome analysis of Acetobacter pasteurianus during acetic acid fermentation.  

PubMed

Acetic acid bacteria (AAB) are Gram-negative, strictly aerobic microorganisms that show a unique resistance to ethanol (EtOH) and acetic acid (AcH). Members of the Acetobacter and Gluconacetobacter genera are capable of transforming EtOH into AcH via the alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes and are used for the industrial production of vinegar. Several mechanisms have been proposed to explain how AAB resist high concentrations of AcH, such as the assimilation of acetate through the tricarboxylic acid (TCA) cycle, the export of acetate by various transporters and modifications of the outer membrane. However, except for a few acetate-specific proteins, little is known about the global proteome responses to AcH. In this study, we used 2D-DIGE to compare the proteome of Acetobacter pasteurianus LMG 1262(T) when growing in glucose or ethanol and in the presence of acetic acid. Interesting protein spots were selected using the ANOVA p-value of 0.05 as threshold and 1.5-fold as the minimal level of differential expression, and a total of 53 proteins were successfully identified. Additionally, the size of AAB was reduced by approximately 30% in length as a consequence of the acidity. A modification in the membrane polysaccharides was also revealed by PATAg specific staining. PMID:22155126

Andrés-Barrao, Cristina; Saad, Maged M; Chappuis, Marie-Louise; Boffa, Mauro; Perret, Xavier; Ortega Pérez, Ruben; Barja, François

2012-03-16

123

Mode of Action of the Antibacterial Compound Dequalinium Acetate  

PubMed Central

Dequalinium acetate is taken up rapidly by bacterial cells. Unlike the membrane-active drugs exemplified by cetrimide or chlorhexidine, its capacity for damaging the plasma membrane is low. The drug appears to penetrate quite rapidly into the cytoplasm where its effect seems to be exerted. A review of the evidence obtained in this study suggests that nucleic acid-containing components of the cell may be the prime target of this compound. PMID:4975451

Hugo, W. B.; Frier, M.

1969-01-01

124

New applications of kenaf ( Hibiscus cannabinus L.) as microfiltration membranes  

Microsoft Academic Search

An attempt to explore the possibility of kenaf (Hibiscus cannabinus L.) as microfiltration membrane has been carried out in this work. The pulp was acetylated by anhydride acetic acid to produce cellulose acetate with an acetyl content of 40.40%. Membranes were prepared by phase inversion method using polymer concentrations varied between 14% and 18% (w\\/w). It was found that membrane

C. L. Radiman; S. Widyaningsih; S. Sugesty

2008-01-01

125

Gel Electrophoresis Lab: Paternity Case  

NSDL National Science Digital Library

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators provides instructions for conducting a gel electrophoresis lab. Students will try to solve a paternity case with this activity by obtaining a DNA fingerprint from each potential father, the mother and the child. This activity may be downloaded in PDF file format. A data collection sheet and student questions are also included.

2013-07-05

126

Vinegar as a burn-down herbicide: Acetic acid concentrations, application volumes, and adjuvants  

Technology Transfer Automated Retrieval System (TEKTRAN)

Acetic acid acts as a contact herbicide, injuring and killing plants by first destroying the cell membranes, which causes the rapid desiccation of the plant tissues. Vinegars with acetic acid concentrations of 11% or greater can burn the skin and cause serious to severe eye injury, including blindn...

127

Techniques For Focusing In Zone Electrophoresis  

NASA Technical Reports Server (NTRS)

In two techniques for focusing in zone electrophoresis, force of applied electrical field in each charged particle balanced by restoring force of electro-osmosis. Two techniques: velocity-gradient focusing (VGF), suitable for rectangular electrophoresis chambers; and field-gradient focusing (FGF), suitable for step-shaped electrophoresis chambers.

Sharnez, Rizwan; Twitty, Garland E.; Sammons, David W.

1994-01-01

128

Capillary electrophoresis with contactless conductivity detection for the determination of carnitine and acylcarnitines in clinical samples  

Microsoft Academic Search

A capillary electrophoresis method with contactless conductivity detection was developed for the quantification of carnitine and six acylcarnitines in plasma and urine samples. The running buffer employed consisted of 500mmol\\/L acetic acid, 1.0mmol\\/L hydroxypropyl-?-cyclodextrin and 0.05% Tween at a pH of 2.6. Under these conditions, the isomeric valproyl- and octanoyl-carnitines could be distinguished. The linearity was in the range from

Worapan Pormsila; Réjane Morand; Stephan Krähenbühl; Peter C. Hauser

2011-01-01

129

Electrophoresis 1994, IS, 591-615 Capillary electrophoresis of DNA in ultradilute polymer solutions 597 Annelise E. Barron  

E-print Network

Electrophoresis 1994, IS, 591-615 Capillary electrophoresis of DNA in ultradilute polymer solutions electrophoresis in ultradilute polymer solutions Using capillary electrophoresis, large DNA molecules (2.0-23.1 kbp) may be rapidly separated in ultradilute polymer solutions (

Barron, Annelise E.

130

Electrophoresis in strong electric fields.  

PubMed

Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a function of the electric field strength, particle size, electrolyte concentration and the adsorbed polymer amount. It has been shown that the electrophoretic velocity of the particles/cells increases with field strength linearly up to about 100 and 200 V/cm (for cells) without and with adsorbed polymers both in pure water and in electrolyte solutions. In line with the theoretical predictions, in stronger fields substantial non-linear effects were recorded (V(ef)~E(3)). The ef velocity of unipolar ion-type conducting (ion-exchanger particles and fibres), electron-type conducting (magnesium and Mg/Al alloy) and semiconductor particles (graphite, activated carbon, pyrite, molybdenite) increases significantly with the electric field (V(ef)~E(2)) and the particle's size but is almost independent of the ionic strength. These trends are inconsistent with Smoluchowski's equation for dielectric particles, but are consistent with the Dukhin-Mishchuk theory of superfast electrophoresis. PMID:19041962

Barany, Sandor

2009-01-01

131

Capillary electrophoresis systems and methods  

SciTech Connect

An embodiment of the invention is directed to a capillary electrophoresis apparatus comprising a plurality of separation micro-channels. A sample loading channel communicates with each of the plurality of separation channels. A driver circuit comprising a plurality of electrodes is configured to induce an electric field across each of the plurality of separation channels sufficient to cause analytes in the samples to migrate along each of the channels. The system further comprises a plurality of detectors configured to detect the analytes.

Dorairaj, Rathissh (Hillsboro, OR); Keynton, Robert S. (Louisville, KY); Roussel, Thomas J. (Louisville, KY); Crain, Mark M. (Georgetown, IN); Jackson, Douglas J. (New Albany, IN); Walsh, Kevin M. (Louisville, KY); Naber, John F. (Goshen, KY); Baldwin, Richard P. (Louisville, KY); Franco, Danielle B. (Mount Washington, KY)

2011-08-02

132

Agarose Gel Electrophoresis of RNA  

Microsoft Academic Search

\\u000a Gel electrophoresis is one of the most important techniques currently available for the fractionation of RNA. The experimental\\u000a procedure is relatively simple, but nevertheless achieves very reproducible results and high resolution. RNA is a polyanion\\u000a and will therefore migrate toward the positive electrode in an electric field. If the migration occurs through a gel matrix\\u000a of carefully chosen pore size,

Robert J. Slater

133

Acetic acid bacteria in oenology  

Microsoft Academic Search

Acetic acid bacteria have always been considered the bad mi- croorganisms of oenology; responsible for wine spoiling (vine- gary taint). The taxonomy and our knowledge of the metabo- lism of acetic acid bacteria are rapidly evolving, especially as new molecular biology techniques are applied to this fastidious group of microorganisms, which are still rather difficult to work with. The dramatic

A. Mas; M. J. Torija; A. González; M. Poblet; J. M. Guillamón

134

Molecular Structure of Phenylmercuric acetate  

NSDL National Science Digital Library

Phenylmercuric acetate is white to white-yellow crystalline powder that is odorless. This phenyl mercury compound is used mainly as a fungicide, herbicide, slimicide and bacteriocide. Phenylmercuric acid serves as a preservative in canned paint, eye ointments and drops, injectable solutions, skin disinfectants and in cosmetics products such as hair shampoos, mouthwashes and toothpastes. It is also used in contraceptive gels and foams. Phenylmercuric acetate is prepared by interaction of benzene with mercuric acetate in glacial acetic acid. Phenylmercuric acetate's former production and use as a fungicide and as a mildew inhibitor in paints may have resulted in its direct release to the environment. This substance is very toxic to aquatic organisms and may be hazardous to the environment.

2004-11-10

135

Membrane humidity control investigation  

NASA Technical Reports Server (NTRS)

The basic performance data on a hollow fiber membrane unit that removes water from a breathing gas loop by diffusion is presented. Using available permeability data for cellulose acetate, a preliminary design was made of a dehumidifier unit that would meet the problem statement.

Elam, J.; Ruder, J.; Strumpf, H.

1974-01-01

136

Scaleable production and separation of fermentation-derived acetic acid. Final CRADA report.  

SciTech Connect

Half of U.S. acetic acid production is used in manufacturing vinyl acetate monomer (VAM) and is economical only in very large production plants. Nearly 80% of the VAM is produced by methanol carbonylation, which requires high temperatures and exotic construction materials and is energy intensive. Fermentation-derived acetic acid production allows for small-scale production at low temperatures, significantly reducing the energy requirement of the process. The goal of the project is to develop a scaleable production and separation process for fermentation-derived acetic acid. Synthesis gas (syngas) will be fermented to acetic acid, and the fermentation broth will be continuously neutralized with ammonia. The acetic acid product will be recovered from the ammonium acid broth using vapor-based membrane separation technology. The process is summarized in Figure 1. The two technical challenges to success are selecting and developing (1) microbial strains that efficiently ferment syngas to acetic acid in high salt environments and (2) membranes that efficiently separate ammonia from the acetic acid/water mixture and are stable at high enough temperature to facilitate high thermal cracking of the ammonium acetate salt. Fermentation - Microbial strains were procured from a variety of public culture collections (Table 1). Strains were incubated and grown in the presence of the ammonium acetate product and the fastest growing cultures were selected and incubated at higher product concentrations. An example of the performance of a selected culture is shown in Figure 2. Separations - Several membranes were considered. Testing was performed on a new product line produced by Sulzer Chemtech (Germany). These are tubular ceramic membranes with weak acid functionality (see Figure 3). The following results were observed: (1) The membranes were relatively fragile in a laboratory setting; (2) Thermally stable {at} 130 C in hot organic acids; (3) Acetic acid rejection > 99%; and (4) Moderate ammonia flux. The advantages of producing acetic acid by fermentation include its appropriateness for small-scale production, lower cost feedstocks, low energy membrane-based purification, and lower temperature and pressure requirements. Potential energy savings of using fermentation are estimated to be approximately 14 trillion Btu by 2020 from a reduction in natural gas use. Decreased transportation needs with regional plants will eliminate approximately 200 million gallons of diesel consumption, for combined savings of 45 trillion Btu. If the fermentation process captures new acetic acid production, savings could include an additional 5 trillion Btu from production and 7 trillion Btu from transportation energy.

Snyder, S. W.; Energy Systems

2010-02-08

137

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

138

Mathematical models of continuous flow electrophoresis: Electrophoresis technology  

NASA Technical Reports Server (NTRS)

Two aspects of continuous flow electrophoresis were studied: (1) the structure of the flow field in continuous flow devices; and (2) the electrokinetic properties of suspended particles relevant to electrophoretic separations. Mathematical models were developed to describe flow structure and stability, with particular emphasis on effects due to buoyancy. To describe the fractionation of an arbitrary particulate sample by continuous flow electrophoresis, a general mathematical model was constructed. In this model, chamber dimensions, field strength, buffer composition, and other design variables can be altered at will to study their effects on resolution and throughput. All these mathematical models were implemented on a digital computer and the codes are available for general use. Experimental and theoretical work with particulate samples probed how particle mobility is related to buffer composition. It was found that ions on the surface of small particles are mobile, contrary to the widely accepted view. This influences particle mobility and suspension conductivity. A novel technique was used to measure the mobility of particles in concentrated suspensions.

Saville, Dudley A.

1986-01-01

139

Electromigration dispersion in Capillary Electrophoresis  

PubMed Central

In a previous paper (S. Ghosal and Z. Chen Bull. Math. Biol. 2010 72, pg. 2047) 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

2012-01-01

140

Capillary electrophoresis for pharmaceutical analysis.  

PubMed

This chapter describes the application of capillary electrophoresis (CE) to pharmaceutical analysis. The areas of pharmaceutical analysis covered are enantiomer separation, analysis of small molecules such as amino acids or drug counter-ions, pharmaceutical assay, related substances determinations, and physiochemical measurements such as log P and pKa of compounds. The different electrophoretic modes available and their advantages for pharmaceutical analysis are described. Recent applications of CE for each subject area are tabulated with electrolyte details. Information on electrolyte choice and method optimization to obtain optimal separations is included. PMID:18392572

Marsh, Alex; Broderick, Margo; Altria, Kevin; Power, Joe; Donegan, Sheila; Clark, Brian

2008-01-01

141

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

142

Molecular Structure of Sodium acetate  

NSDL National Science Digital Library

Sodium acetate is known for its ability to supercool. It freezes at 130 degrees, but can exist as a liquid at a much lower temperature. In order to melt solidified sodium acetate, however, every single crystal must liquify, otherwise the material will recrystallize. Sodium acetate has been used as a deicer for roads and runways. It is also used a component of buffer systems and in the manufacture of pharmaceuticals and heat pads. The compound is quite stable. It may act as an irritant and be harmful if inhaled or absorbed through the skin.

2002-08-26

143

Cellulose acetate as solid phase in ELISA for plague.  

PubMed

Antigen from Yersinia pestis was adsorbed on cellulose acetate discs (0.5 cm of diameter) which were obtained from dialysis membrane by using a paper punch. ELISA for human plague diagnosis was carried out employing this matrix and was capable to detect amount of 1.3 microg of antigen, 3,200 times diluted positive serum using human anti-IgG conjugate diluted 1:4,000. No relevant antigen lixiviation from the cellulose acetate was observed even after washing the discs 15 times. The discs were impregnated by the coloured products from the ELISA development allowing its use in dot-ELISA. Furthermore, cellulose acetate showed a better performance than the conventional PVC plates. PMID:10656712

Barbosa, A D; Barros, F S; Callou, E Q; Almeida, A M; Araujo, A M; Azevedo, W M; Carvalho, L B

2000-01-01

144

Conducting Polymer Electrodes for Gel Electrophoresis  

PubMed Central

In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that ?-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation. PMID:24586761

Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D.

2014-01-01

145

Biotechnology Curriculum Freshman Exploratory: Electrophoresis  

NSDL National Science Digital Library

Gel electrophoresis is used in many areas of biotechnology and forensics. It is based on the concept that mixtures of substances can be separated by electrical force. The direction and speed of migration through the field is dependent on several factors. All substances are made of molecules that can be positively charged, negatively charged or neutral. These characteristics can be used to separate molecules when they are placed in a gel that has an electrical field. The gels generally used are made of agarose, a purified version of agar used in making bacterial plates. These gels are a porous material that acts as a molecular sieve through which smaller molecules can move more easily than larger ones. They move toward the opposite charged side of the gel with smaller pieces of DNA moving farther from the well compared to larger pieces. In this activity, students will identify separate molecules in a mixture by exposing them to an electric field, determine the charge and size of a molecule by its movement in a gel, and explain the importance of electrophoresis as a tool in biotechnology. This activity may be downloaded in Microsoft Word Doc file format.

Kurtz, Mary Jane

146

Capillary electrophoresis for drug analysis  

NASA Astrophysics Data System (ADS)

Capillary electrophoresis (CE) is a high resolution separation technique which is amenable to a wide variety of solutes, including compounds which are thermally degradable, non-volatile and highly polar, and is therefore well suited for drug analysis. Techniques which have been used in our laboratory include electrokinetic chromatography (ECC), free zone electrophoresis (CZE) and capillary electrochromatography (CEC). ECC, which uses a charged run buffer additive which migrates counter to osmotic flow, is excellent for many applications, including, drug screening and analyses of heroin, cocaine and methamphetamine samples. ECC approaches include the use of micelles and charged cyclodextrins, which allow for the separation of complex mixtures. Simultaneous separation of acidic, neutral and basic solutes and the resolution of optical isomers and positional isomers are possible. CZE has been used for the analysis of small ions (cations and anions) in heroin exhibits. For the ECC and CZE experiments performed in our laboratory, uncoated capillaries were used. In contrast, CEC uses capillaries packed with high performance liquid chromatography stationary phases, and offers both high peak capacities and unique selectivities. Applications include the analysis of cannabinoids and drug screening. Although CE suffers from limited concentration sensitivity, it is still applicable to trace analysis of drug samples, especially when using injection techniques such as stacking, or detection schemes such as laser induced fluorescence and extended pathlength UV.

Lurie, Ira S.

1999-02-01

147

Preclinical safety of anecortave acetate.  

PubMed

A number of preclinical safety pharmacology and toxicity studies have been performed on the angiostatic cortisene anecortave acetate in various species and using different routes of administration (oral, intravenous, subcutaneous, topical ocular, intraocular injection, posterior juxtascleral) and a wide range of doses (0-1,000 mg/kg). Anecortave acetate did not interact with a broad panel of pharmacological receptors and had no apparent pharmacological effects on major organ systems including the central nervous, gastrointestinal, renal, cardiovascular, and respiratory systems. Oral, topical ocular, and posterior juxtascleral administration of anecortave acetate had no significant ocular or systemic side effects or toxicity. In addition, there was no significant carcinogenic or reproductive/developmental toxicity associated with anecortave acetate in genotoxicity, carcinogenicity, and reproductive toxicity studies. PMID:17240255

Heaton, Jim; Kastner, Philip; Hackett, Robert

2007-01-01

148

Acetate transport across the intestinal epithelium of an herbivorous teleost. [Oreochromis mossambicus  

SciTech Connect

{sup 3}H-acetate transport across the upper intestine of the tilapia, Oreochromis mossabicus, using brush border and basolateral membrane vesicles, and intestinal sheets mounted in modified Ussing chambers was investigated. Brush border and basolateral vesicles demonstrated qualitatively similar anion antiport activity where, in the presence of a full profile of organic and inorganic anions, volatile fatty acids (VFA; acetate, propionate, butyrate) and bicarbonate showed reciprocal trans-stimulation and cis-inhibition of {sup 3}H-acetate influx, suggesting both membranes had the same VFA/bicarbonate exchange mechanism. Kinetic analysis of {sup 3}H-acetate influx into brush border and basolateral vesicles revealed different half-saturation constants (Km) as a function of external acetate concentrations (6.43 mM and 11.91 mM, respectively) and as a function of internal bicarbonate (5.89 mM and 0.41 mM, respectively). Intestinal sheets supported net absorptive fluxes when serosal acetate concentrations were held steady at 1.0 mM and mucosal acetate was varied from 1.60 to 10.0 mM. Unidirectional fluxes were significantly diminished by the addition of acetazolamide. This study postulates a transcellular transport pathway for VFA whereby qualitatively similar antiporters in series lead to a downhill flow of luminal acetate to the blood, which is driven by intracellular carbonic anhydrase and a transmural VFA concentration gradient.

Titus, E.; Ahearn, G.A. (Univ. of Hawaii, Honolulu (United States))

1990-02-26

149

Analytical biotechnology: Capillary electrophoresis and chromatography  

SciTech Connect

The papers describe the separation, characterization, and equipment required for the electrophoresis or chromatography of cyclic nucleotides, pharmaceuticals, therapeutic proteins, recombinant DNA products, pheromones, peptides, and other biological materials. One paper, On-column radioisotope detection for capillary electrophoresis, has been indexed separately for inclusion on the data base.

Horvath, C.; Nikelly, J.G. (eds.)

1990-01-01

150

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

151

Pre-Cast Gel Electrophoresis Guide  

E-print Network

Novex® Pre-Cast Gel Electrophoresis Guide Version B January 27, 2003 IM-1002 Novex® Pre-Cast Gel Electrophoresis Guide General information and protocols for using Novex® pre-cast gels www.invitrogen.com tech.....................................................................................................................1 Novex® Pre-Cast Gels

Kirschner, Marc W.

152

Compensating for Electro-Osmosis in Electrophoresis  

NASA Technical Reports Server (NTRS)

Simple mechanical adjustment eliminates transverse velocity component. New apparatus for moving-wall electrophoresis increases degree of collimation of chemical species in sample stream. Electrophoresis chamber set at slight angle in horizontal plane to adjust angle between solution flow and wall motion. Component of velocity created cancels electro-osmotic effect.

Rhodes, Percy H.; Snyder, Robert S.

1987-01-01

153

Interfacial Synthesis in the Preparation of Reverse Osmosis Membranes  

Microsoft Academic Search

Reverse osmosis membranes are currently finding increasing use in the production of potable water from salt-laden water sources, and in the purification and recycle of industrial process waters. Most reverse osmosis membranes are comprised either of polyamide hollow fibers or cellulose acetate sheet films. A new type of reverse osmosis membrane, made by the interfacial synthesis of ultrathin membranes directly

J. E. Cadotte; R. S. King; R. J. Majerle; R. J. Petersen

1981-01-01

154

Electrophoresis-mass spectrometry probe  

DOEpatents

The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface. 8 figs.

Andresen, B.D.; Fought, E.R.

1987-11-10

155

Microchip electrophoresis with sample stacking.  

PubMed

A fused quartz microchip with a serpentine column geometry is fabricated to perform rapid microchip electrophoresis of dansylated amino acids. A 67 mm separation column is constructed in a 7 x 10 mm area on a quartz substrate using standard photolithographic, etching and deposition techniques. Buffer and sample flows within the channel manifold are precisely controlled through potentials applied to the reservoirs. To enhance the detection limits, a stacking injection technique is used to concentrate the sample at the inlet of the separation column. The stacked injections exhibit high reproducibility (2.1% relative standard deviation in peak area). Using a separation length of 67 mm and a separation field strength of 1100 V/cm, separations are performed in < or = 15 s generating approximately 40,000 theoretical plates. PMID:7588514

Jacobson, S C; Ramsey, J M

1995-04-01

156

Free Solution Electrophoresis of Homopolyelectrolytes  

E-print Network

We investigate the behavior of single polyelectrolytes in multivalent salt solutions under the action of electric fields through computer simulations. The chain is unfolded in a strong electric field and aligned parallel to the field direction, and the chain size shows a sigmoidal transition. The unfolding electric field $E^*$ depends on the salt concentration and scales as $V^{-1/2}$ with $V$ being the ellipsoidal volume occupied by the chain. The magnitude of the electrophoretic mobility of chain drastically increases during the unfolding. The fact that $E^*$ depends on the chain length provides a plausible mechanism to separate long charged homopolymers by size in free solution electrophoresis via the unfolding transition of globule polyelectrolytes condensed by multivalent salt.

Pai-Yi Hsiao; Kun-Mao Wu

2008-08-22

157

Two Electrophoresis Experiments for Freshmen in the Health Professions.  

ERIC Educational Resources Information Center

Describes procedures involved with paper electrophoresis separation of amino acids, gel electrophoresis separation of DNA, and design of an electrophoresis tank. Describes experiments using paper (amino acids) and gel (deoxyribonucleic acid fragments). Provides material lists, procedures, and discussion. (JM)

Brabson, G. Dana; Waugh, David S.

1986-01-01

158

The defect of Mk erythrocytes as revealed by sodium dodecylsulphate--polyacrylamide gel electrophoresis.  

PubMed

The membrane glycoprotein defect of Mk red cells was studied using discontinuous sodium dodecylsulphate--polyacrylamide gel electrophoresis, carbohydrate analytical procedures and lectins. The results suggest that Mk erythrocyte membranes contain only about half of the normal amount of the MN and Ss sialoglycoproteins, both molecules being not qualitatively different from normal. The major membrane protein exhibits an increased molecular weight in the above red cells. Some data on Mg and Miltenberger class five cells are presented for comparison. The results on Mk erythrocytes support the operon concept of the MNSs blood group system proposed previously. PMID:894053

Dahr, W; Uhlenbruck, G; Knott, H

1977-06-01

159

Lactate and acetate production in Listeria innocua.  

PubMed

Listeria innocua NCTC 11289 was grown aerobically in continuous culture in defined media at 30 degrees C. Both acetate and lactate were produced, the proportion of acetate decreased with increasing dilution rate. Enzymatic analysis showed lactate dehydrogenase was activated 10-fold by fructose-1, 6-bisphosphate. The presence of phosphate acetyltransferase and acetate kinase but not pyruvate oxidase was detected, suggesting the sequential action of phosphate acetyltransferase and acetate kinase to produce acetate from acetyl CoA via acetylphosphate. PMID:8987454

Kelly, A F; Patchett, R A

1996-08-01

160

Micropreparative electrophoresis of globin chains on cellulose acetate film in structural identification of abnormal human hemoglobins.  

PubMed

A simple and rapid micropreparative method for isolating 5 to 30 nmol of globin chain, followed by structural identification of abnormal human hemoglobins, is described. The method is based on the electrophoretic separation of globins on ordinary Cellogel films under denaturating conditions with subsequent cutting out of the protein zones and solubilization of Cellogel and the electrophoretic buffer components in a specially selected solvent in which the globin chain undergoes quantitative precipitation. The method makes it possible to simplify and speed up the structural identification of commonly occurring abnormal hemoglobins. The advantages and limitations of the method are discussed along with its potential uses in structural protein chemistry. PMID:3407907

Spivak, V A; Lutsenko, I N

1988-05-15

161

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

162

Biodegradable cellulose acetate nanofiber fabrication via electrospinning.  

PubMed

Nanofiber manufacturing is one of the key advancements in nanotechnology today. Over the past few years, there has been a tremendous growth of research activities to explore electrospinning for nanofiber formation from a rich variety of materials. This quite simple and cost effective process operates on the principle that the solution is extracted under the action of a high electric field. Once the voltage is sufficiently high, a charged jet is ejected following a complicated looping trajectory. During its travel, the solvent evaporates leaving behind randomly oriented nanofibers accumulated on the collector. The combination of their nanoscale dimensionality, high surface area, porosity, flexibility and superior strength makes the electrospun fibers suitable for several value-added applications, such as filters, protecting clothes, high performance structures and biomedical devices. In this study biodegradable cellulose acetate (CA) nanofibrous membranes were produced using electrospinning. The device utilized consisted of a syringe equipped with a metal needle, a microdialysis pump, a high voltage supply and a collector. The morphology of the yielded fibers was determined using SEM. The effect of various parameters, including electric field strength, tip-to-collector distance, solution feed rate and composition on the morphological features of the electrospun fibers was examined. The optimum operating conditions for the production of uniform, non-beaded fibers with submicron diameter were also explored. The biodegradable CA nanofiber membranes are suitable as tissue engineering scaffolds and as reinforcements of biopolymer matrix composites in foils by ultrasonic welding methods. PMID:21133179

Christoforou, Theopisti; Doumanidis, Charalabos

2010-09-01

163

Micelles Protect and Concentrate Activated Acetic Acid  

NASA Astrophysics Data System (ADS)

As more and more exoplanets are discovered and the habitability of such planets is considered, one can turn to searching for the origin of life on Earth in order to better understand what makes a habitable planet. Activated acetic acid, or methyl thioacetate, has been proposed to be central to the origin of life on Earth, and also as an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about three orders of magnitude faster (K = 0.00663 s^-1; 100°C, pH 7.5, concentration = 0.33mM) than published rates for its catalyzed production making it unlikely to accumulate under prebiotic conditions. However, we also observed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. We found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid micelles. Thus, the hydrophobic regions of prebiotic micelles and early cell membranes could have offered a refuge for this energetic molecule increasing its lifetime in close proximity to the reactions for which it would be needed. Methyl thioacetate could thus be important for the origin of life on Earth and perhaps for better understanding the potential habitability of other planets.

Todd, Zoe; House, C.

2014-01-01

164

Comparison of high-performance liquid chromatography and capillary zone electrophoresis for the determination of parabens in a cosmetic product  

Microsoft Academic Search

A high-performance liquid chromatographic method (HPLC) and a capillary zone electrophoresis method (CZE) have been developed for the analysis of methylparaben, ethylparaben, propylparaben and butylparaben in a commercial cosmetic product. A very simple extraction procedure with acidified diethylether was developed. The HPLC method involved a C18 reversed-phase column and a gradient of methanol and water-acetic acid (1%). Electrophoretic separation was

L Labat; E Kummer; P Dallet; J. P Dubost

2000-01-01

165

Nanodisc-solubilized membrane protein library reflects the membrane proteome  

PubMed Central

The isolation and identification of unknown membrane proteins offers the prospect of discovering new pharmaceutical targets and identifying key biochemical receptors. However, interactions between membrane protein targets and soluble ligands are difficult to study in vitro due to the insolubility of membrane proteins in non-detergent systems. Nanodiscs, nanoscale discoidal lipid bilayers encircled by a membrane scaffold protein belt, have proven to be an effective platform to solubilize membrane proteins and have been used to study a wide variety of purified membrane proteins. This report details the incorporation of an unbiased population of membrane proteins from Escherichia coli membranes into Nanodiscs. This solubilized membrane protein library (SMPL) forms a soluble in vitro model of the membrane proteome. Since Nanodiscs contain isolated proteins or small complexes, the SMPL is an ideal platform for interactomics studies and pull-down assays of membrane proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the protein population before and after formation of the Nanodisc library indicates that a large percentage of the proteins are incorporated into the library. Proteomic identification of several prominent bands demonstrates the successful incorporation of outer and inner membrane proteins into the Nanodisc library. PMID:23400332

Marty, Michael T.; Wilcox, Kyle C.; Klein, William L.; Sligar, Stephen G.

2013-01-01

166

Nanodisc-solubilized membrane protein library reflects the membrane proteome.  

PubMed

The isolation and identification of unknown membrane proteins offers the prospect of discovering new pharmaceutical targets and identifying key biochemical receptors. However, interactions between membrane protein targets and soluble ligands are difficult to study in vitro due to the insolubility of membrane proteins in non-detergent systems. Nanodiscs, nanoscale discoidal lipid bilayers encircled by a membrane scaffold protein belt, have proven to be an effective platform to solubilize membrane proteins and have been used to study a wide variety of purified membrane proteins. This report details the incorporation of an unbiased population of membrane proteins from Escherichia coli membranes into Nanodiscs. This solubilized membrane protein library (SMPL) forms a soluble in vitro model of the membrane proteome. Since Nanodiscs contain isolated proteins or small complexes, the SMPL is an ideal platform for interactomics studies and pull-down assays of membrane proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the protein population before and after formation of the Nanodisc library indicates that a large percentage of the proteins are incorporated into the library. Proteomic identification of several prominent bands demonstrates the successful incorporation of outer and inner membrane proteins into the Nanodisc library. PMID:23400332

Marty, Michael T; Wilcox, Kyle C; Klein, William L; Sligar, Stephen G

2013-05-01

167

Acid diffusion through polyaniline membranes  

SciTech Connect

Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

Su, T.M.; Huang, S.C.; Conklin, J.A. [Univ. of California, Los Angeles, CA (United States)] [and others

1995-12-01

168

Voltammetric detection for capillary electrophoresis.  

PubMed

Several approaches to implementing amperometric detection for capillary electrophoresis have been reported. This report describes the development of a voltammetric detector for CE. The detector is designed to minimize distortion of the voltammetry due to ohmic potential drop. This was accomplished by using a cast Nafion detection cell at the end of the separation capillary. The cast Nafion detection cell provided a low-dead-volume, low-resistance cell that minimized ohmic potential drop and peak band broadening. The ability to detect the current due to oxidation of analytes superimposed on a large background current was also improved. A dynamic background subtraction scheme was used in which a second working electrode, positioned in the electrochemical cell but outside of the detection cell, was used to compensate for the background current in real time. The output of the compensating working electrode was subtracted from the output of the detecting working electrode prior to analog-to-digital conversion. Postexperimental digital background subtraction was also implemented. This approach provided optimal elimination of the background current with maximal detection of the analytical signal. The voltammetric detector developed produced high-quality voltammetric response of analytes with injected concentrations as low as 0.20 microM. The system was evaluated by obtaining CE voltammograms of a mixture of eight test phenolic acids. PMID:9253250

Park, S; McGrath, M J; Smyth, M R; Diamond, D; Lunte, C E

1997-08-01

169

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. PMID:20238181

Ghosal, Sandip; Chen, Zhen

2011-01-01

170

Haemoglobin electrophoresis patterns in Barbados.  

PubMed

Despite the extensive data on haemoglobinopathies and their widespread geographic distribution, the number of prospective Caribbean studies which document the prevalence of haemoglobinopathies from birth are few. The purpose of this cohort study was to document the prevalence of haemoglobinopathies in newborn infants in Barbados. One thousand successively collected cord bloods of newborn infants were screened for haemoglobinopathies using the Paragon acid electrophoresis technique. Seventeen infants were retested at 1 year of age to confirm the diagnosis. Three mothers could not be located so their infants' diagnoses could not be confirmed. From the 997 blood samples with conclusive results, a haemoglobinopathy was found in 72 (7%) samples. Laboratory analysis revealed: 925 patients (93%) with Hb AA, 41 (4%) with Hb AS, 27 (2.7%) with Hb AC, 2 (0.2%) with Hb SS, 1 (0.1%) with Hb CC and 1 (0.1%) with Hb SC. The prevalence of the sickle gene and number of cases of Sickle Cell anaemia in the Barbadian population is less than has been reported from other regional territories. PMID:10639844

St John, M A; Lungu, F N

1999-12-01

171

Acetate fuels the cancer engine.  

PubMed

Cancer cells have distinctive nutrient demands to fuel growth and proliferation, including the disproportionate use of glucose, glutamine, and fatty acids. Comerford et al. and Mashimo et al. now demonstrate that several types of cancer are avid consumers of acetate, which facilitates macromolecular biosynthesis and histone modification. PMID:25525870

Lyssiotis, Costas A; Cantley, Lewis C

2014-12-18

172

Desmopressin Acetate in Intracranial Haemorrhage  

PubMed Central

Introduction. The secondary increase in the size of intracranial haematomas as a result of spontaneous haemorrhage or trauma is of particular relevance in the event of prior intake of platelet aggregation inhibitors. We describe the effect of desmopressin acetate as a means of temporarily stabilising the platelet function. Patients and Methods. The platelet function was analysed in 10 patients who had received single (N = 4) or multiple (N = 6) doses of acetylsalicylic acid and 3 patients (control group) who had not taken acetylsalicylic acid. All subjects had suffered intracranial haemorrhage. Analysis was performed before, half an hour and three hours after administration of desmopressin acetate. Statistical analysis was performed by applying a level of significance of P ? 0.05. Results. (1) Platelet function returned to normal 30 minutes after administration of desmopressin acetate. (2) The platelet function worsened again after three hours. (3) There were no complications related to electrolytes or fluid balance. Conclusion. Desmopressin acetate can stabilise the platelet function in neurosurgical patients who have received acetylsalicylic acid prior to surgery without causing transfusion-related side effects or a loss of time. The effect is, however, limited and influenced by the frequency of drug intake. Further controls are needed in neurosurgical patients. PMID:25610644

Kapapa, Thomas; Röhrer, Stefan; Struve, Sabine; Petscher, Matthias; König, Ralph; Wirtz, Christian Rainer; Woischneck, Dieter

2014-01-01

173

[Comparison of different buffer systems for separation of 15 nucleosides by capillary electrophoresis].  

PubMed

The most suitable background electrolytes (BGEs) for simultaneous separation of 15 nucleosides by different modes of capillary electrophoresis (CE) were obtained. Various modes of CE were performed including capillary zone electrophoresis (CZE), capillary electrophoresis-electrospray ionization-time of flight mass spectrometry (CE-ESI-TOF/MS) and micellar electrokinetic chromatography (MEKC). The electrolyte buffers using sodium tetraborate decahydrate, disodium hydrogen phosphate, sodium acetate, sodium bicarbonate, ammonium acetate or 1, 2-diamino-ethane (DEA) were tested, and the best of them were systematically optimized. In CZE mode, the nucleosides could not be separated completely with sodium tetraborate decahydrate or disodium hydrogen phosphate as BGEs, demonstrating the limited applicability of the two buffer systems for complex samples. However, with 300 mmol/L DEA (containing 2% acetone) as BGE, 15 nucleosides could be separated with good resolution and peak shape, which proved that the DEA buffer was most suitable in CZE. The best buffer system in MEKC mode was 25 mmol/L disodium hydrogen phosphate with 70 mmol/L sodium dodecyl sulfate (SDS), and it was successfully applied for the separation of the nucleosides in Chinese Anthopleura lanthogrammica Berkly. The optimum buffer system for CE-ESI-TOF/MS analysis was 20 mmol/L ammonium acetate (pH 10.0). In the positive ion mode, the MS signals of each compound were better than those in the literature using DEA as BGE. The results of this study demonstrated the applicability of different buffer systems for the simultaneous separation of 15 nucleosides, and were helpful for the development of CE method in complex sample separation. PMID:22032157

Shi, Qian; Chen, Junhui; Li, Xin; Cao, Wei; Zheng, Li; Zang, Jiaye; Wang, Xiaoru

2011-06-01

174

Induced-charge electrophoresis near a wall  

E-print Network

Induced-charge electrophoresis (ICEP) has mostly been analyzed for asymmetric particles in an infinite fluid, but channel walls in real systems further break symmetry and lead to dielectrophoresis (DEP) in local field ...

Kilic, Mustafa Sabri

175

Capillary electrophoresis electrospray ionization mass spectrometry interface  

DOEpatents

The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

Smith, Richard D. (Richland, WA); Severs, Joanne C. (Hayward, CA)

1999-01-01

176

Study of disposable microdevices for DNA electrophoresis  

E-print Network

A study was undertaken to determine if a microfluidic chip, made of economical plastic materials, is feasible. The chip was designed to perform gel electrophoresis, specifically of DNA fragments for either sequencing or ...

Timp, Winston (Winston G.)

2005-01-01

177

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

178

Capillary Electrophoresis Applied to Polysaccharide Characterization  

Microsoft Academic Search

\\u000a Capillary electrophoresis is a consolidated analytical approach for the structural characterization of polysaccharide mono-\\u000a and oligomer constituents, as demonstrated in this chapter, which surveys several applications of this technique on chemically\\u000a and enzymatically degraded polysaccharides, covering the last 10 to 12 years. Capillary electrophoresis is also demonstrated\\u000a to be highly reliable for determination of polysaccharides in biological samples, as it

Mila Toppazzini; Anna Coslovi; Sergio Paoletti

179

Free-Flow Open-Chamber Electrophoresis  

NASA Technical Reports Server (NTRS)

Free-flow open-chamber electrophoresis variant of free-flow electrophoresis performed in chamber with open ends and in which velocity of electro-osmotic flow adjusted equal to and opposite mean electrophoretic velocity of sample. Particles having electrophoretic mobilities greater than mean mobility of sample particles move toward cathode, those with mobilities less move toward anode. Technique applied to separation of components of mixtures of biologically important substances. Sensitivity enhanced by use of tapered chamber.

Sharnez, Rizwan; Sammons, David W.

1994-01-01

180

Rapid microwell polymerase chain reaction with subsequent ultrathin-layer gel electrophoresis of DNA.  

PubMed

Large-scale genotyping, mapping and expression profiling require affordable, fully automated high-throughput devices enabling rapid, high-performance analysis using minute quantities of reagents. In this paper, we describe a new combination of microwell polymerase chain reaction (PCR) based DNA amplification technique with automated ultrathin-layer gel electrophoresis analysis of the resulting products. This technique decreases the reagent consumption (total reaction volume 0.75-1 microL), the time requirement of the PCR (15-20 min) and subsequent ultrathin-layer gel electrophoresis based fragment analysis (5 min) by automating the current manual procedure and reducing the human intervention using sample loading robots and computerized real time data analysis. Small aliquots (0.2 microL) of the submicroliter size PCR reaction were transferred onto loading membranes and analyzed by ultrathin-layer gel electrophoresis which is a novel, high-performance and automated microseparation technique. This system employs integrated scanning laser-induced fluorescence-avalanche photodiode detection and combines the advantages of conventional slab and capillary gel electrophoresis. Visualization of the DNA fragments was accomplished by "in migratio" complexation with ethidium bromide during the electrophoresis process also enabling real time imaging and data analysis. PMID:11870770

Shandrick, Sarah; Ronai, Zsolt; Guttman, András

2002-02-01

181

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.

182

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

PubMed

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. PMID:22465769

Pielesz, A

2012-07-01

183

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2012 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...

2012-04-01

184

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2014 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...

2014-04-01

185

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

186

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2011 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...

2011-04-01

187

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2010 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...

2010-04-01

188

Recent advances in affinity capillary electrophoresis for binding studies.  

PubMed

The present review covers recent advances and important applications of affinity capillary electrophoresis (ACE). It provides an overview about various ACE types, including ACE-MS, the multiple injection mode, the use of microchips and field-amplified sample injection-ACE. The most common scenarios of the studied affinity interactions are protein-drug, protein-metal ion, protein-protein, protein-DNA, protein-carbohydrate, carbohydrate-drug, peptide-peptide, DNA-drug and antigen-antibody. Approaches for the improvements of ACE in term of precision, rinsing protocols and sensitivity are discussed. The combined use of computer simulation programs to support data evaluation is presented. In conclusion, the performance of ACE is compared with other techniques such as equilibrium dialysis, parallel artificial membrane permeability assay, high-performance affinity chromatography as well as surface plasmon resonance, ultraviolet, circular dichroism, nuclear magnetic resonance, Fourier transform infrared, fluorescence, MS and isothermal titration calorimetry. PMID:25534793

Albishri, Hassan M; Deeb, Sami El; AlGarabli, Noura; AlAstal, Raghda; Alhazmi, Hassan A; Nachbar, Markus; El-Hady, Deia Abd; Wätzig, Hermann

2014-12-01

189

Acetate kinase activity in mycoplasmas.  

PubMed

Acetate kinase activity was assayed in 13 mycoplasmas. Nine species exhibited the enzymic activity in the direction of either synthesis of acetylphosphate or adenosine triphosphate. On the other hand Mycoplasma orale, Mycoplasma arthritidis, Ureaplasma urealyticum (10 serotypes), and two strains of Anaeroplasma species exhibited only minimal levels of the enzymic activity. In these four species, the enzyme does not seem to play a key role in adenosine triphosphate formation. PMID:6263869

Muhlrad, A; Peleg, I; Robertson, J A; Robinson, I M; Kahane, I

1981-07-01

190

Application of denaturing gradient gel electrophoresis (DGGE) and temperature gradient gel electrophoresis (TGGE) in microbial ecology  

Microsoft Academic Search

Here, the state of the art of the application of denaturing gradient gel electrophoresis (DGGE) and temperature gradient gel electrophoresis (TGGE) in microbial ecology will be presented. Furthermore, the potentials and limitations of these techniques will be discussed, and it will be indicated why their use in ecological studies has become so important. Abbreviations: ARDRA - amplified ribosomal DNA restriction

Gerard Muyzer; Kornelia Smalla

1998-01-01

191

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

192

Free flow cell electrophoresis using zwitterionic buffer  

NASA Technical Reports Server (NTRS)

Studies of a zwitterionic buffer formulated for cell electrophoresis were done using the McDonnell-Douglas Continuous Flow Electrophoresis System. Standard buffers were analyzed for their stability in the electrical field and the results showed that both buffers tested were inherently unstable. Further, titration studies showed that the standards buffers buffered poorly at the pH employed for electrophoresis. The zwitterionic buffer buffered well at its nominal pH and was shown to be stable in the electrical field. Comparative studies of the buffer with standard cell separation buffers using formalin fixed rabbit and goose red blood cells showed that the zwitterionic buffer gave better resolution of the fixed cells. Studies with viable hybridoma cells showed that buffer Q supported cell viability equal to Hank's Balanced Salt Solution and that hybridoma cells in different stages of the growth cycle demonstrated reproducible differences in electrophoretic mobility.

Rodkey, R. Scott

1990-01-01

193

Denaturation and electrophoresis of RNA with formaldehyde.  

PubMed

Electrophoretic size fractionation can be used to denature and separate large mRNA molecules (0.5-10 kb) on formaldehyde-containing agarose gels. Formaldehyde contains a carbonyl group that reacts to form Schiff bases with the imino or amino groups of guanine, adenine, and cytosine. These covalent adducts prevent normal base pairing and maintain the RNA in a denatured state. Because these adducts are unstable, formaldehyde must be present in the gel to maintain the RNA in the denatured state. This protocol describes the preparation of an agarose gel with formaldehyde and its setup in a horizontal electrophoresis apparatus. RNA samples are prepared and denatured in a solution of formamide and formaldehyde and, with 0.5- to 10-kb size markers, subjected to electrophoresis through the gel. Following electrophoresis, the gel is stained to visualize RNA markers or rRNA using one of several different types of stains. PMID:25646498

Rio, Donald C

2015-01-01

194

Application of Microchip Electrophoresis for Clinical Tests  

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. In addition, the analysis has expanded to an analytical field like not only the analysis of DNA but also the analysis of RNA, the protein, the sugar chain, and the cellular function, etc. In this report, we showed that high-performance monitoring systems for human blood glucose levels and ?-amylase activity in human plasma using microchip electrophoresis.

Yatsushiro, Shouki; Kataoka, Masatoshi

195

Molecular Structure of Ethyl acetate  

NSDL National Science Digital Library

Ethyl acetate is a colorless, volatile liquid with a mild and fragrant odor. It is used as solvent in chemistry laboratories but can also be found in many household products such as paints, coatings, and adhesives. The compound is also used in some extraction processes such as decaffeination or purification of antibiotics. It is present in both nail polish and removers. Some synthetic fruit essences may contain this and other esters. Etymologists like to use this solvent for insect collecting as the vapor kill the insect quickly and keep it soft for mounting.

2006-03-08

196

Cellulose membranes for reverse osmosis part II. Improving RO membranes prepared from non-woody cellulose  

Microsoft Academic Search

Experiments were carried out to minimize the stages of preparing reverse osmosis (RO) desalination membranes at economical cost and to improve the transport properties of RO membranes prepared from non-wood fibrous materials (cotton linters and bagasse pulp) to approach those prepared from imported viscose pulp and purchased cellulose acetate (see Part I). Further study was carried out on examining the

Altaf H. Basta; Houssni El-Saied; M. Elberry

2003-01-01

197

Study on dicarboxylic acids in aerosol samples with capillary electrophoresis.  

PubMed

The research was performed to study the simultaneous detection of a homologous series of ? , ? -dicarboxylic acids (C2-C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50? ? L. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2-C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10?ng/m(3). PMID:24729915

Adler, Heidi; Sirén, Heli

2014-01-01

198

Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis  

PubMed Central

The research was performed to study the simultaneous detection of a homologous series of ?, ?-dicarboxylic acids (C2–C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50??L. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2–C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10?ng/m3. PMID:24729915

Adler, Heidi; Sirén, Heli

2014-01-01

199

A Simple Vertical Slab Gel Electrophoresis Apparatus.  

ERIC Educational Resources Information Center

Describes an inexpensive, easily constructed, and safe vertical slab gel kit used routinely for sodium dodecyl sulphate-polyacrylamide gel electrophoresis research and student experiments. Five kits are run from a single transformer. Because toxic solutions are used, students are given plastic gloves and closely supervised during laboratory…

Carter, J. B.; And Others

1983-01-01

200

Two-Dimensional Electrophoresis of Serum Proteins  

Microsoft Academic Search

A METHOD of zone electrophoresis in starch gels has recently been described by one of us1. The high degree of resolution obtained with this method when applied to serum appears to be due to the use of a supporting medium the pore size of which approaches the molecular dimensions of some of the proteins involved, so that resolution by molecular

O. Smithies; M. D. POULIK

1956-01-01

201

DNA ADDUCT RESEARCH WITH CAPILLARY ELECTROPHORESIS  

EPA Science Inventory

DNA's central importance in all biological systems dictates a wide variety of DNA-related research. or much of this research, the utilization of capillary electrophoresis (CE) can be of significant advantage. pen-tube CE yields excellent separations of DNA components, which can b...

202

Protein Charge Ladders, Capillary Electrophoresis, and  

E-print Network

Protein Charge Ladders, Capillary Electrophoresis, and the Role of Electrostatics in Biomolecular Introduction Life rests on a web of molecular recognition;1,2 the folding of proteins, the hybridization the recognition site of the protein. Hydrophobic interactions, although still a challenge to describe

Prentiss, Mara

203

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

2013-11-21

204

Role of gravity in preparative electrophoresis  

NASA Technical Reports Server (NTRS)

The fundamental formulas of electrophoresis are derived microscopically and applied to the problem of isotachophoresis. A simple physical model of the isotachophoresis front is proposed. The front motion and structure are studied in the simplified case without convection, diffusion and non-electric external forces.

Bier, M.

1975-01-01

205

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

206

Diamond cubic phase of monoolein and water as an amphiphilic matrix for electrophoresis of oligonucleotides.  

PubMed

We used a cubic liquid crystal formed by the nonionic monoglyceride monoolein and water as a porous matrix for the electrophoresis of oligonucleotides. The diamond cubic phase is thermodynamically stable when in contact with a water-rich phase, which we exploit to run the electrophoresis in the useful submarine mode. Oligonucleotides are separated according to size and secondary structure by migration through the space-filling aqueous nanometer pores of the regular liquid crystal, but the comparatively slow migration means the cubic phase will not be a replacement for the conventional DNA gels. However, our demonstration that the cubic phase can be used in submarine electrophoresis opens up the possibility for a new matrix for electrophoresis of amphiphilic molecules. From this perspective, the results on the oligonucleotides show that water-soluble particles of nanometer size, typical for the hydrophilic parts of membrane-bound proteins, may be a useful separation motif. A charged contamination in the commercial sample of monoolein, most likely oleic acid that arises from its hydrolysis, restricts useful buffer conditions to a pH below 5.6. PMID:16853397

Carlsson, Nils; Winge, Ann-Sofie; Engström, Sven; Akerman, Björn

2005-10-01

207

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

208

Nonradioactive telomerase activity assay by microchip electrophoresis: privileges to the classical gel electrophoresis assay.  

PubMed

The present study accents on the privileges of microchip-based electrophoresis to the conventional gel electrophoresis in separation of telomerase repeat amplification protocol/polymerase chain reaction (PCR) ladder products obtained in telomerase-catalyzed reaction in cancer cells. We try to clarify the interpretation of the results obtained by both electrophoretic procedures and to avoid misinterpretation as a result of PCR-dependent artefacts. PMID:16078194

Zhelev, Zhivko; Bakalova, Rumiana; Ewis, Ashraf; Ohba, Hideki; Ishikawa, Mitsuru; Baba, Yoshinobu

2005-08-01

209

Positron scattering from vinyl acetate  

NASA Astrophysics Data System (ADS)

Using a Beer-Lambert attenuation approach, we report measured total cross sections (TCSs) for positron scattering from vinyl acetate (C4H6O2) in the incident positron energy range 0.15-50 eV. In addition, we also report an independent atom model with screening corrected additivity rule computation results for the TCSs, differential and integral elastic cross sections, the positronium formation cross section and inelastic integral cross sections. The energy range of these calculations is 1-1000 eV. While there is a reasonable qualitative correspondence between measurement and calculation for the TCSs, in terms of the energy dependence of those cross sections, the theory was found to be a factor of ˜2 larger in magnitude at the lower energies, even after the measured data were corrected for the forward angle scattering effect.

Chiari, L.; Zecca, A.; Blanco, F.; García, G.; Brunger, M. J.

2014-09-01

210

Extractive fermentation of acetic acid  

SciTech Connect

In this technoeconomic evaluation of the manufacture of acetic acid by fermentation, the use of the bacterium: Acetobacter suboxydans from the old vinegar process was compared with expected performance of the newer Clostridium thermoaceticum bacterium. Both systems were projected to operate as immobilized cells in a continuous, fluidized bed bioreactor, using solvent extraction to recover the product. Acetobacter metabolizes ethanol aerobically to produce acid at 100 g/L in a low pH medium. This ensures that the product is in the form of a concentrated extractable free acid, rather than as an unextractable salt. Unfortunately, yields from glucose by way of the ethanol fermentation are poor, but near the biological limits of the organisms involved. Conversely, C. thermoaceticum is a thermophilic anaerobe that operates at high fermentation rates on glucose at neutral pH to produce acetate salts directly in substantially quantitative yields. However, it is severely inhibited by product, which restricts concentration to a dilute 20 g/L. An improved Acetobacter system operating with recycled cells at 50 g/L appears capable of producing acid at $0.38/lb, as compared with a $0.29/lb price for synthetic acid. However, this system has only a limited margin for process improvement. The present Clostridium system cannot compete, since the required selling price would be $0.42/lb. However, if the organism could be adapted to tolerate higher product concentrations at acid pH, selling price could be reduced to $0.22/lb, or about 80% of the price of synthetic acid.

Busche, R.M. [Bio En-Gene-Er Associates, Inc., Wilmington, DE (United States)

1991-12-31

211

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

2013-07-01

212

Molecular cloning of the plant plasma membrane H + ATPase  

Microsoft Academic Search

Summary  Mineral transport across the plasma membrane of plant cells is controlled by an electrochemical gradient of protons. This\\u000a gradient is generated by an ATP-consuming enzyme in the membrane known as a proton pump, or H+-ATPase. The protein has a catalytic subunit of Mr=100,000 and is a prominent band when plasma membrane proteins are analyzed\\u000a by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

T. K. Surowy; M. R. Sussman

1987-01-01

213

Free-flow electrophoresis with electrode-less injection molded chips  

NASA Astrophysics Data System (ADS)

In this work we present the first approach towards low-cost free-flow electrophoresis (FFE) devices utilizing injection molding as a microfabrication process which has the potential to manufacture FFE chips at a cost which make their use commercially viable. This is achieved by realizing a new straightforward micro free-flow electrophoresis (?FFE) design ensuring both, bubble free electrophoretic separation and effective electrical connection by implementing miniaturized partitioning bars. This creates a defined open gap of 20 ?m in height and 500 ?m in width between separation zone and electrode channels. The thermoplastic ?FFE chips are ready to use, there is no need for a subsequent labor-intensive implementation of membranes or salt bridges to separate the electrode channels from the separation zone.

Köhler, Stefan; Becker, Holger; Beushausen, Volker; Hüttner, Wilhelm; Wackerbarth, Hainer; Beckert, Erik; Howitz, Steffen; Belder, Detlev

2011-02-01

214

21 CFR 184.1005 - Acetic acid.  

Code of Federal Regulations, 2011 CFR

...as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2 H4 O2 , CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant...fermentation of carbohydrates or by organic synthesis. The principal...

2011-04-01

215

Capillary zone electrophoresis-mass spectrometer interface  

DOEpatents

A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.

D`Silva, A.

1996-08-06

216

Capillary zone electrophoresis-mass spectrometer interface  

DOEpatents

A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.

D'Silva, Arthur (Ames, IA)

1996-08-06

217

Portable electrophoresis apparatus using minimum electrolyte  

NASA Technical Reports Server (NTRS)

An electrophoresis unit for use in conducting electrophoretic analysis of specimens is described. The unit includes a sealable container in which a substrate mounted specimen is suspended in an electrolytic vapor. A heating unit is employed to heat a supply of electrolyte to produce the vapor. The substrate is suspended within the container by being attached between a pair of clips which also serve as electrodes to which a direct current power source may be connected.

Stevens, M. R.; Vickers, J. M. (inventors)

1976-01-01

218

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

219

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

220

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

221

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

222

Membrane stabilizer  

SciTech Connect

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.

Mingenbach, William A. (P.O. Box 49, Taos, NM 87571)

1988-01-01

223

Contribution of dialysate acetate to energy metabolism: Metabolic implications  

Microsoft Academic Search

Contribution of dialysate acetate to energy metabolism: Metabolic implications. During hemodialysis large amounts of acetate enter the bloodstream. Generally, it is assumed that this exogenous acetate load is oxidized immediately to carbon dioxide and water; however, the rate of plasma acetate oxidation and the effect of acetate oxidation on energy metabolism during hemodialysis has not been determined previously. The rates

Charles L Skutches; Miles H Sigler; Brendan P Teehan; Joseph H Cooper; George A Reichard

1983-01-01

224

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

225

Quenched phosphorescence, a new detection method in capillary electrophoresis.  

PubMed

The applicability of quenched phosphorescence as a detection mode in capillary electrophoresis (CE) was explored for a number of analyte classes and buffer systems. The detection method is based on the quenching of biacetyl phosphorescence (biacetyl is a constituent of the CE buffer) by the analytes via various mechanisms (energy transfer, electron transfer and, possibly, hydrogen donation) and gives rise to negative peaks in the electropherograms. A number of buffers in the pH range 4.7-11.5, frequently used in CE, were tested for their compatibility with this detection mode. Borate, succinate, malonate, acetate, and phosphate buffers (pH 4.7-8.5) could be used without any problems. With a pH of ca. 8.5 or higher the baseline declined with time, while at a pH higher than 9.5 no signal at all was obtained. Obviously, the noise on the phosphorescence signal (i.e., the baseline) determines the ultimate analyte detection limits (LODs). The baseline signal-to-noise ratio, usually denoted as the dynamic reserve (DR), was enhanced ca. 25-fold compared to direct biacetyl excitation by sensitization of the biacetyl phosphorescence by 1,5-naphthalenedisulfonic acid, and by application of a total emission mirror (TEM). A concentration of 1 x 10(-3) M 1,5-naphthalenedisulfonic acid was found to be optimal. For the buffer systems considered, the DR was typically ca. 300-600 under optimized conditions (noise defined as 1 x sigma). Investigated analytes include naphthalenesulfonic acids (NS), nitrophenols, hydroxybenzoic acids, amino acids, and dithiocarbamates (DTCs.). For most of these, the LODs were in the 10(-7)-10(-8) M range, which is significantly lower than with direct or indirect absorption detection. PMID:10826674

Kuijt, J; Brinkman, U A; Gooijer, C

2000-04-01

226

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. PMID:24098238

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

2013-01-01

227

Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography.  

PubMed

Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the characterization of liposome drug delivery systems, e.g., for the investigation of encapsulation efficiency and drug leakage. The well-known characteristics of capillary electrophoresis, i.e., low sample volume requirement, high separation efficiency in aqueous media without a stationary phase, minimal sample preparation, and a high degree of automation, makes it an attractive approach in liposome research. PMID:22824223

Franzen, Ulrik; Østergaard, Jesper

2012-12-01

228

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

229

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. PMID:24023914

Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

2013-01-01

230

Evaluation of non-aqueous capillary zone electrophoresis for the determination of histamine H2 receptor antagonists in pharmaceuticals.  

PubMed

A new non-aqueous capillary electrophoresis method is proposed for the separation and simultaneous determination of cimetidine, ranitidine, roxatidine, nizatidine and famotidine by using a 30-cm long × 75 µm i.d. fused silica capillary and UV detection at 214 nm. Using a temperature of 25°C, an applied voltage of 15 kV, and a background electrolyte consisting of methanol containing 10 mM ammonium acetate and 0.2% acetic acid allowed the analytes to be separated in less than 4 min. The limits of detection obtained ranged from 7 and 17 µg L(-1). The proposed method was successfully used to determine the analytes in pharmaceutical preparations and its results were checked against an HPLC method. PMID:21478620

Nevado, J J Berzas; Peñalvo, G Castañeda; Dorado, R M Rodríguez

2011-01-01

231

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry for top-down characterization of the Mycobacterium marinum secretome.  

PubMed

Capillary zone electrophoresis (CZE) with an electrokinetically pumped sheath-flow nanospray interface was coupled with a high-resolution Q-Exactive mass spectrometer for the analysis of culture filtrates from Mycobacterium marinum. We confidently identified 22 gene products from the wildtype M. marinum secretome in a single CZE-tandem mass spectrometry (MS/MS) run. A total of 58 proteoforms were observed with post-translational modifications including signal peptide removal, N-terminal methionine excision, and acetylation. The conductivities of aqueous acetic acid and formic acid solutions were measured from 0.1% to 100% concentration (v/v). Acetic acid (70%) provided lower conductivity than 0.25% formic acid and was evaluated as low ionic-strength and a CZE-MS compatible sample buffer with good protein solubility. PMID:24725189

Zhao, Yimeng; Sun, Liangliang; Champion, Matthew M; Knierman, Michael D; Dovichi, Norman J

2014-05-20

232

21 CFR 522.2478 - Trenbolone acetate and estradiol benzoate.  

Code of Federal Regulations, 2010 CFR

...false Trenbolone acetate and estradiol benzoate. 522.2478 Section 522.2478...2478 Trenbolone acetate and estradiol benzoate. (a) Specifications . Each implant...trenbolone acetate and 3.5 mg estradiol benzoate. (2) 4 pellets, each pellet...

2010-04-01

233

Rapid analytical and preparative isolation of functional endosomes by free flow electrophoresis  

PubMed Central

Endosomes are prelysosomal organelles that serve as an intracellular site for the sorting, distribution, and processing of receptors, ligands, fluid phase components, and membrane proteins internalized by endocytosis. Whereas the overall functions of endosomes are increasingly understood, little is known about endosome structure, composition, or biogenesis. In this paper, we describe a rapid procedure that permits analytical and preparative isolation of endosomes from a variety of tissue culture cells. The procedure relies on a combination of density gradient centrifugation and free flow electrophoresis. It yields a fraction of highly purified, functionally intact organelles. As markers for endosomes in Chinese hamster ovary cells, we used endocytosed horseradish peroxidase, FITC-conjugated dextran, and [35S]methionine-labeled Semliki Forest virus. Total postnuclear supernatants, crude microsomal pellets, or partially purified Golgi fractions were subjected to free flow electrophoresis. Endosomes and lysosomes migrated together as a single anodally deflected peak separated from most other organelles (plasma membrane, mitochondria, endoplasmic reticulum, and Golgi). The endosomes and lysosomes were then resolved by centrifugation in Percoll density gradients. Endosomes prepared in this way were enriched up to 70-fold relative to the initial homogenate and were still capable of ATP- dependent acidification. By electron microscopy, the isolated organelles were found to consist of electron lucent vacuoles and tubules, many of which could be shown to contain an endocytic tracer (e.g., horseradish peroxidase). SDS PAGE analysis of integral and peripheral membrane proteins (separated from each other by condensation in Triton X-114) revealed a unique and restricted subset of proteins when compared with lysosomes, the unshifted free flow electrophoresis peak, and total cell protein. Altogether, the purification procedure takes 5-6 h and yields amounts of endosomes (150-200 micrograms protein) sufficient for biochemical, immunological, and functional analysis. PMID:3031085

1987-01-01

234

Disruption of the acetate kinase (ack) gene of Clostridium acetobutylicum results in delayed acetate production.  

PubMed

In microorganisms, the enzyme acetate kinase (AK) catalyses the formation of ATP from ADP by de-phosphorylation of acetyl phosphate into acetic acid. A mutant strain of Clostridium acetobutylicum lacking acetate kinase activity is expected to have reduced acetate and acetone production compared to the wild type. In this work, a C. acetobutylicum mutant strain with a selectively disrupted ack gene, encoding AK, was constructed and genetically and physiologically characterized. The ack (-) strain showed a reduction in acetate kinase activity of more than 97% compared to the wild type. The fermentation profiles of the ack (-) and wild-type strain were compared using two different fermentation media, CGM and CM1. The latter contains acetate and has a higher iron and magnesium content than CGM. In general, fermentations by the mutant strain showed a clear shift in the timing of peak acetate production relative to butyrate and had increased acid uptake after the onset of solvent formation. Specifically, in acetate containing CM1 medium, acetate production was reduced by more than 80% compared to the wild type under the same conditions, but both strains produced similar final amounts of solvents. Fermentations in CGM showed similar peak acetate and butyrate levels, but increased acetoin (60%), ethanol (63%) and butanol (16%) production and reduced lactate (-50%) formation by the mutant compared to the wild type. These findings are in agreement with the proposed regulatory function of butyryl phosphate as opposed to acetyl phosphate in the metabolic switch of solventogenic clostridia. PMID:22249720

Kuit, Wouter; Minton, Nigel P; López-Contreras, Ana M; Eggink, Gerrit

2012-05-01

235

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. PMID:21209842

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

2010-01-01

236

Biotechnology Laboratory: Gel Electrophoresis of Dyes  

NSDL National Science Digital Library

A portion of the Partnership for Plant Genomics Education, hosted by the University of California-Davis, this PDF presents a student activity where students will use agarose gel electrophoresis to separate several different dyes. The lab is described as a âÂÂprecursor to DNA separationsâ and thus provides an important step in the subject matter. The lab provides for students: detailed instructions, background information, and a quiz and group questions. Answers to the questions, and also the general objective of the lab, are provided for the instructor. Overall, the lab is introductory in nature and perfect for any science classroom.

2008-12-05

237

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

238

RNA purification by preparative polyacrylamide gel electrophoresis.  

PubMed

Preparative polyacrylamide gel electrophoresis (PAGE) is a powerful tool for purifying RNA samples. Denaturing PAGE allows separation of nucleic acids that differ by a single nucleotide in length. It is commonly used to separate and purify RNA species after in vitro transcription, to purify naturally occurring RNA variants such as tRNAs, to remove degradation products, and to purify labeled RNA species. To preserve RNA integrity following purification, RNA is usually visualized by UV shadowing or stained with ethidium bromide or SYBR green dyes. PMID:24034329

Petrov, Alexey; Wu, Tinghe; Puglisi, Elisabetta Viani; Puglisi, Joseph D

2013-01-01

239

Hybrid slab-microchannel gel electrophoresis system  

DOEpatents

A hybrid slab-microchannel gel electrophoresis system. 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.

Balch, Joseph W. (Livermore, CA); Carrano, Anthony V. (Livermore, CA); Davidson, James C. (Livermore, CA); Koo, Jackson C. (San Ramon, CA)

1998-01-01

240

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

241

Starch-gel Electrophoresis of Anterior Pituitary Hormones  

Microsoft Academic Search

SEPARATION of pituitary hormones by zone electrophoresis on paper has not proved very successful, possibly due to complex formation between proteins1. Starch-gel zone electrophoresis introduced by Smithies2,3 separates proteins not only by their net charge but also by their molecular size. This procedure has superior resolving power to paper or agar-gel zone electrophoresis and has been successfully applied to the

K. A. Ferguson; A. L. C. Wallace

1961-01-01

242

Pervaporation with chitosan membranes. I. Separation of water from ethylene glycol by a chitosan\\/polysulfone composite membrane  

Microsoft Academic Search

A chitosan\\/polysulfone composite membrane was prepared. The preparation procedure involved dissolution of chitosan in dilute aqueous acetic acid to form chitosan salt, coating of the chitosan salt solution on a porous polysulfone substrate, and regeneration of chitosan by alkaline treatment. The membrane was tested for selective removal of water from aqueous ethylene glycol solutions by pervaporation. The effects of operating

Xianshe Feng; Robert Y. M. Huang

1996-01-01

243

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

2006-03-31

244

Indium acetate toxicity in male reproductive system in rats.  

PubMed

Indium, a rare earth metal characterized by high plasticity, corrosion resistance, and a low melting point, is widely used in the electronics industry, but has been reported to be an environmental pollutant and a health hazard. We designed a study to investigate the effects of subacute exposure of indium compounds on male reproductive function. Twelve-week old male Sprague-Dawley rats were randomly divided into test and control groups, and received weekly intraperitoneal injections of indium acetate (1.5 mg/kg body weight) and normal saline, respectively, for 8 weeks. Serum indium levels, cauda epididymal sperm count, motility, morphology, chromatin DNA structure, mitochondrial membrane potential, oxidative stress, and testis DNA content were investigated. The indium acetate-treated group showed significant reproductive toxicity, as well as an increased percentage of sperm morphology abnormality, chromatin integrity damage, and superoxide anion generation. Furthermore, positive correlations among sperm morphology abnormalities, chromatin DNA damage, and superoxide anion generation were also noted. The results of this study demonstrated the toxic effect of subacute low-dose indium exposure during the period of sexual maturation on male reproductive function in adulthood, through an increase in oxidative stress and sperm chromatin DNA damage during spermiogenesis, in a rodent model. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014. PMID:25044390

Lee, Kuo-Hsin; Chen, Hsiu-Ling; Leung, Chung-Man; Chen, Hsin-Pao; Hsu, Ping-Chi

2014-07-01

245

Determination of Herbicides Paraquat, Glyphosate, and Aminomethylphosphonic Acid in Marijuana Samples by Capillary Electrophoresis.  

PubMed

In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15-0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user. PMID:25413634

Lanaro, Rafael; Costa, José L; Cazenave, Silvia O S; Zanolli-Filho, Luiz A; Tavares, Marina F M; Chasin, Alice A M

2014-11-20

246

Cytoplasmic polyhedrosis virus classification by electropherotype; validation by serological analyses and agarose gel electrophoresis.  

PubMed

Serological analyses of several different cytoplasmic polyhedrosis viruses (CPVs), including two type 1 CPVs from Bombyx mori, type 1 CPV from Dendrolimus spectabilis, type 12 CPV from Autographa gamma, type 2 CPV from Inachis io, type 5 CPV from Orgyia pseudotsugata and type 5 CPV from Heliothis armigera, demonstrated a close correlation between the antigenic properties of the polyhedrin or virus particle structural proteins and the genomic dsRNA electropherotypes. The dsRNAs of these viruses were analysed by electrophoresis in 3% and 10% polyacrylamide gels with a discontinuous Tris-HCl/Tris-glycine buffer system or by 1% agarose gel electrophoresis using a continuous Tris-acetate-EDTA buffer system. Electrophoretic analysis in agarose gels was found to be the most suitable for the classification of CPV isolates into electropherotypes, and the results obtained showed a close correlation with the observed antigenic relationships between different virus isolates. However, electrophoretic analysis in 10% polyacrylamide gels was most sensitive for the detection of intra-type variation and the presence of mixed virus isolates. PMID:2499658

Mertens, P P; Crook, N E; Rubinstein, R; Pedley, S; Payne, C C

1989-01-01

247

Determination of ciclopirox olamine in pharmaceutical products by capillary electrophoresis with capacitively coupled contactless conductivity detection.  

PubMed

This paper describes the determination of ciclopirox olamine in pharmaceutical formulations using capillary electrophoresis with capacitively coupled contactless conductivity detection. In an alkaline medium, ciclopirox olamine is converted into an anionic species and its detection is possible in capillary electrophoresis with capacitively coupled contactless conductivity detection without an electroosmotic flow modifier, because it is a low-mobility species. A linear working range from 2.64 to 264 ?g/mL in sodium hydroxide electrolyte as well as low detection limit (0.39 ?g/mL) and a good repeatability (RSD = 3.4% for 264 ?g/mL ciclopirox solution (n = 10)) were achieved. It was also possible to determine olamine in its cationic form when acetic acid was used as the electrolyte solution. The results obtained include a linear range from 26.4 to 184.8 ?g/mL and a detection limit of 2.6 ?g/mL olamine. The proposed methods were applied to the analysis of commercial pharmaceutical products and the results were compared with the values indicated by the manufacturer as well as those obtained using a titrimetric method recommended by American Pharmacopoeia. PMID:21394732

Felix, Fabiana Silva; do Lago, Claudimir Lucio; Angnes, Lúcio

2011-04-01

248

Capillary electrophoresis coupled with automated fraction collection.  

PubMed

A fraction collector based on a drop-on-demand ink-jet printer was developed to interface capillary zone electrophoresis with a 96 well microtiter plate. We first evaluated the performance of the collector by using capillary zone electrophoresis to analyze a 1mM solution of tetramethylrhodamine; a fluorescent microtiter plate reader was then used to detect the analyte and characterize fraction carryover between wells. Relative standard deviation in peak height was 20% and the relative standard deviation in migration time was 1%. The mean and standard deviation of the tetramethylrhodamine peak width was 5 ± 1 s and likely limited by the 4-s period between droplet deposition. We next injected a complex mixture of DNA fragments and used real-time PCR to quantify the product in a CE-SELEX experiment. The reconstructed electrophoretic peak was 27 s in duration. Finally, we repeated the experiment in the presence of a 30-µM thrombin solution under CE-SELEX conditions; fractions were collected and next-generation sequencing was used to characterize the DNA binders. Over 25,000 sequences were identified with close matches to known thrombin binding aptamers. PMID:25159411

Huge, Bonnie Jaskowski; Flaherty, Ryan J; Dada, Oluwatosin O; Dovichi, Norman J

2014-12-01

249

Morphology and transport characteristics of poly(ethylene- co-vinyl acetate)\\/clay nanocomposites  

Microsoft Academic Search

Poly(ethylene-co-vinyl acetate)\\/clay nanocomposite membranes were prepared with different clay loadings. The morphology of the nanocomposites was investigated using X-ray diffraction technique and transmission electron microscopy. The dispersion of layered silicates decreased with increasing filler loading. Samples with low filler content showed excellent dispersion of layered silicates resulting in a partially exfoliated structure. The transport characteristics of aromatic hydrocarbons through the

M. N. Muralidharan; S. Anil Kumar; Sabu Thomas

2008-01-01

250

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

2013-02-01

251

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. PMID:20955010

Becker, Jorg D.; Sá-Correia, Isabel

2010-01-01

252

Membrane proteins and proteomics: love is possible, but so difficult.  

PubMed

Despite decades of extensive research, the large-scale analysis of membrane proteins remains a difficult task. This is due to the fact that membrane proteins require a carefully balanced hydrophilic and lipophilic environment, which optimum varies with different proteins, while most protein chemistry methods work mainly, if not only, in water-based media. Taking this review [Santoni, Molloy and Rabilloud, Membrane proteins and proteomics: un amour impossible? Electrophoresis 2000, 21, 1054-1070] as a pivotal paper, the current paper analyzes how the field of membrane proteomics exacerbated the trend in proteomics, i.e. developing alternate methods to the historical two-dimensional electrophoresis, and thus putting more and more pressure on the mass spectrometry side. However, in the case of membrane proteins, the incentive in doing so is due to the poor solubility of membrane proteins. This review also shows that in some situations, where this solubility problem is less acute, two-dimensional electrophoresis remains a method of choice. Last but not least, this review also critically examines the alternate approaches that have been used for the proteomic analysis of membrane proteins. PMID:19517508

Rabilloud, Thierry

2009-06-01

253

A centrifugal method for the evaluation of polymer membranes for reverse osmosis  

NASA Technical Reports Server (NTRS)

A rapid and simple method employing the laboratory centrifuge shows promise for evaluation of membrane performance during reverse osmosis. Results are presented for cellulose acetate membranes for rejection of salt and urea dissolved solids. Implications of the study are to rapid screening of membrane performance, use in laboratories with limited facilities, and possible space waste water purification.

Hollahan, J. R.; Wydeven, T.; Mccullough, R. P.

1973-01-01

254

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. PMID:19344146

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

2009-01-01

255

Acetate Transport and Utilization in the Rat Brain  

PubMed Central

Acetate, a glial-specific substrate, is an attractive alternative to glucose for the study of neuronal-glial interactions. The present study investigates the kinetics of acetate uptake and utilization in the rat brain in vivo during infusion of [2-13C]acetate using NMR spectroscopy. When plasma acetate concentration was increased, the rate of brain acetate utilization (CMRace) increased progressively and reached close to saturation for plasma acetate concentration > 2-3 mM, whereas brain acetate concentration continued to increase. The Michaelis-Menten constant for brain acetate utilization ( KMutil=0.01±0.14mM) was much smaller than for acetate transport through the blood-brain barrier ( KMt=4.18±0.83mM). The maximum transport capacity of acetate through the blood-brain barrier ( Vmaxt=0.96±0.18?mol/g/min) was nearly two-fold higher than the maximum rate of brain acetate utilization ( Vmaxutil=0.50±0.08?mol/g/min). We conclude that, under our experimental conditions, brain acetate utilization is saturated when plasma acetate concentrations increase above 2-3 mM. At such high plasma acetate concentration, the rate-limiting step for glial acetate metabolism is not the blood-brain barrier, but occurs after entry of acetate into the brain. PMID:19393008

Deelchand, Dinesh K.; Shestov, Alexander A.; Koski, Dee M.; U?urbil, Kâmil; Henry, Pierre-Gilles

2009-01-01

256

Association and release of the major intrinsic membrane glycoprotein from peripheral nerve myelin.  

PubMed Central

Hypo-osmotic homogenization of the endoneurium from the adult-rat sciatic nerve and subsequent evaluation of the 197 000 g aqueous supernatant by sodium dodecyl sulphate pore-gradient electrophoresis (SDS-p.g.e.) revealed a release of the major glycoprotein (P0) (29 000 Mr) from peripheral nerve myelin. Immunological verification of the presence of this asparagine-linked glycoprotein in the aqueous supernatant was obtained by immune overlay after SDS-p.g.e. and electrophoretic transfer to nitrocellulose using anti-P0 gamma-globulin followed by autoradiographic detection with 125I-protein A. A comparison of successive hypo- and iso-osmotic extractions of the endoneurium revealed that the hypo-osmotic extraction released increasing amounts of P0 into the supernatant fraction, whereas the iso-osmotic treatment revealed lower levels of P0 extracted from the myelin and lesser amounts with each successive extraction. Three successive hypo-osmotic extractions resulted in a 2.0-, 2.9-, and 9.5-fold increase in the amount of P0 released compared with the successive iso-osmotic extractions. Although these results suggest that this major myelin glycoprotein has properties similar to those of extrinsic membrane proteins, temperature-dependent phase-partitioning experiments with Triton X-114 revealed that this glycoprotein is recovered in the detergent-enriched lower phase. These results indicate that this major myelin glycoprotein is an amphipathic integral membrane protein with a distinct hydrophobic domain and yet has solubility characteristics typical of an extrinsic membrane protein. P0 labelled in vitro with [3H]mannose could be immunoprecipitated from the aqueous supernatant with anti-P0 gamma-globulin by centrifugation at 197000g without the addition of second antibody or protein A. Analysis of such an immune precipitate after incorporation in vitro with [14C]acetate to label endoneurial lipids revealed that all major endoneurial lipid classes contained radioactive label, as determined by fluorography after high-performance t.l.c. The mechanism of release of this intrinsic glycoprotein from the myelin membrane, therefore, involves the osmotic-dependent formation of mixed micelles or membrane vesicles with endogenous membrane lipids. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 6. Fig. 7. Fig. 8. Fig. 9. PMID:2408610

Poduslo, J F; Yao, J K

1985-01-01

257

Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.  

PubMed

In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid. PMID:25416587

Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

2014-11-22

258

Pharmacological activity of hyperforin acetate in rats.  

PubMed

Hyperforin, the main antidepressant component of Hypericum extract, is not stable with regard to heat and light. Therefore, we investigated a newly synthetized derivative, hyperforin acetate. Herein we demonstrate its efficacy in animal models sensitive to antidepressant and anxiolytic drugs. In the forced swimming test, triple administration of hyperforin (5-20 mg/kg) significantly reduced the immobility time of rats, while in the learned helplessness test a daily treatment of 10 mg/kg for seven consecutive days was necessary to elicit an antidepressant effect. In the elevated plus-maze and in the light-dark test, the acute administration of hyperforin acetate (3-5 mg/kg) exerted an anxiolytic activity, which, however, was smaller than that of diazepam. The effect was inhibited by the pretreatment of rats with metergoline, a serotoninergic antagonist, but not with CGS-8216, a benzodiazepine receptor antagonist. Hyperforin acetate (3-10 mg/kg) was also able to reduce locomotion in rats without eliciting myorelaxant activity. As Hypericum extract was claimed to exert a potential influence on the liver drug metabolizing system, we showed that neither acute nor repeated oral doses of hyperforin acetate altered pentobarbital sleeping time in rats. Taken together, the present results show that hyperforin acetate is a pharmacologically active derivative of hyperforin and may be a starting point from which to develop new compounds for therapeutic purposes. PMID:12478215

Zanoli, P; Rivasi, M; Baraldi, C; Baraldi, M

2002-12-01

259

Examination of the Protein Composition of the Cell Envelope of Escherichia coli by Polyacrylamide Gel Electrophoresis  

PubMed Central

An envelope preparation containing the cell wall and cytoplasmic membrane of Escherichia coli was obtained by breaking the cells with a French pressure cell and sedimentating the envelope fraction by ultracentrifugation. This fraction was prepared for polyacrylamide gel electrophoresis by dissolving the protein in an acidified N,N?-dimethylformamide, removing lipids by gel filtration in the same organic solvent and removing the solvent by dialysis against aqueous urea solutions. More than 80% of the total protein of the envelope fraction was recovered in soluble form. Electrophoresis on sodium dodecyl sulfate-containing gels yielded from 20 to 30 well-resolved bands of protein. One major protein band was observed on the gels. This protein had a molecular weight of 44,000 and accounted for as much as 40% of the total protein of the envelope fraction. A double-labeling technique was used to examine the protein composition of the envelope fraction from cells grown under different sets of conditions which result in large changes in the levels of membrane-bound oxidative enzymes. These changes in growth conditions resulted in only minor alterations in the protein profiles observed on the gels, suggesting that this organism is able to adapt to changes in growth environment with only minor modifications of the major proteins of the cell envelope. PMID:4923077

Schnaitman, Carl A.

1970-01-01

260

Golgi Enrichment and Proteomic Analysis of Developing Pinus radiata Xylem by Free-Flow Electrophoresis  

PubMed Central

Our understanding of the contribution of Golgi proteins to cell wall and wood formation in any woody plant species is limited. Currently, little Golgi proteomics data exists for wood-forming tissues. In this study, we attempted to address this issue by generating and analyzing Golgi-enriched membrane preparations from developing xylem of compression wood from the conifer Pinus radiata. Developing xylem samples from 3-year-old pine trees were harvested for this purpose at a time of active growth and subjected to a combination of density centrifugation followed by free flow electrophoresis, a surface charge separation technique used in the enrichment of Golgi membranes. This combination of techniques was successful in achieving an approximately 200-fold increase in the activity of the Golgi marker galactan synthase and represents a significant improvement for proteomic analyses of the Golgi from conifers. A total of thirty known Golgi proteins were identified by mass spectrometry including glycosyltransferases from gene families involved in glucomannan and glucuronoxylan biosynthesis. The free flow electrophoresis fractions of enriched Golgi were highly abundant in structural proteins (actin and tubulin) indicating a role for the cytoskeleton during compression wood formation. The mass spectrometry proteomics data associated with this study have been deposited to the ProteomeXchange with identifier PXD000557. PMID:24416096

Macdonald, Lucy J.; Adams, Paul D.; Petzold, Christopher J.; Strabala, Timothy J.; Wagner, Armin; Heazlewood, Joshua L.

2013-01-01

261

Unified Theory for Gel Electrophoresis and Gel Filtration  

Microsoft Academic Search

Unified theory for gel electrophoresis and gel filtration: The behavior of macromolecules in gel filtration and gel electrophoresis may be predicted from Ogston's model for a random meshwork of fibers. This model has been generalized to apply to nonspherical molecules and to several gel types. The model provides equations for inter-relationships between mobility, partition coefficient, gel concentration, and molecular radius;

David Rodbard; Andreas Chrambach

1970-01-01

262

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

263

Analysis of starch structure using fluorophore-assisted carbohydrate electrophoresis.  

PubMed

The analysis of the fine structure of starches is important to the investigation of linkages between starch structure and function and to the investigation of the properties and roles of starch biosynthetic, modifying and degradation enzymes. Fluorophore-assisted carbohydrate electrophoresis has recently been introduced as a method for the analysis of the oligosaccharide populations released by the enzymatic digestion of starches, which has advantages in resolution and sensitivity over previously used methods, and provides the capacity for the facile analysis of oligosaccharide populations on either a molar or mass basis. The use of fluorophore-assisted carbohydrate electrophoresis for the analysis of oligosaccharides is reviewed with particular reference to the choice of label, efficiency of labeling and separation techniques. Examples of separations using slab gel electrophoresis, DNA sequencer analysis and capillary electrophoresis are presented and we conclude that on the basis of resolution and reproducibility, capillary electrophoresis is the method of choice for the separation of oligosaccharides of degree of polymerization from 1 to 100. Examples of isoamylase-debranched starches and glycogens analyzed by capillary electrophoresis are presented. The capillary electrophoresis analysis of starch structure through the analysis of oligosaccharides released by the debranching of limit dextrins derived from starches and glycogens is introduced as a useful diagnostic of starch structure. The potential for future development of novel diagnostics for starch structure using fluorophore-assisted carbohydrate electrophoresis is discussed. PMID:9848667

Morell, M K; Samuel, M S; O'Shea, M G

1998-11-01

264

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

265

Capillary electrophoresis: A comparison to liquid chromatography  

SciTech Connect

Capillary electrophoresis (CE) is undergoing rapid growth at the present time as a separation/analytical tool. In its early days, about 5 years ago, CE was viewed as a complementary tool to LC. it is useful to re-examine this relationship in the context of the changes that have occurred in LC and especially CE. While CE continues to complement LC, clear and unique applications of CE have emerged. For example, CE is fundamentally a solution process, not a surface medicated method. Also, miniaturization may be easier to achieve with CE than LC. On the other hand, preparative scale separations are clearly superior by LC. Using specific applications, we shall highlight the similarities and differences of the two methods. We will conclude with predictions on future directions for CE and LC.

Karger, B.L. [Northeastern Univ., Boston, MA (United States)

1995-12-01

266

Fluid mechanics of continuous flow electrophoresis  

NASA Technical Reports Server (NTRS)

The reported investigation has the objective to provide a basis for understanding the hydrodynamic characteristics of the continuous flow electrophoresis chamber and their effects on the separation process. Particular emphasis is placed on the role buoyancy plays in establishing the basic flow and affecting its stability. The flow and temperature field is discussed, taking into account mathematical models for the structure of the temperature field, models for the structure of the axial velocity field, a two-dimensional constant thermal conductivity model, the axial velocity field, a two-dimensional constant transport properties model, and one-dimensional velocity fields. Questions of hydrodynamic stability are considered, giving attention to the stability of a fully developed flow with an axial temperature gradient.

Saville, D. A.

1978-01-01

267

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

268

High resolution detection system of capillary electrophoresis  

NASA Astrophysics Data System (ADS)

The capillary electrophoresis (CE) with laser induced fluorescence detection (LIFD) system was founded according to confocal theory. The 3-D adjustment of the exciting and collecting optical paths was realized. The photomultiplier tube (PMT) is used and the signals are processed by a software designed by ourselves. Under computer control, high voltage is applied to appropriate reservoirs and to inject and separate DNA samples respectively. Two fluorescent dyes Thiazole Orange (TO) and SYBR Green I were contrasted. With both of the dyes, high signals-to-noise images were obtained with the CE-LIFD system. The single-bases can be distinguished from the electrophoretogram and high resolution of DNA sample separation was obtained.

Wang, Jie; Wang, Li Qiang; Shi, Yan; Zheng, Hua; Lu, Zu Kang

2007-12-01

269

Novel absorption detection techniques for capillary electrophoresis  

SciTech Connect

Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the {mu}M level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

Xue, Y.

1994-07-27

270

Membrane Extraction for Detoxification of Biomass Hydrolysates  

SciTech Connect

Membrane extraction was used for the removal of sulfuric acid, acetic acid, 5-hydroxymethyl furfural and furfural from corn stover hydrolyzed with dilute sulfuric acid. Microporous polypropylene hollow fiber membranes were used. The organic extractant consisted of 15% Alamine 336 in: octanol, a 50:50 mixture of oleyl alcohol:octanol or oleyl alcohol. Rapid removal of sulfuric acid, 5-hydroxymethyl and furfural was observed. The rate of acetic acid removal decreased as the pH of the hydrolysate increased. Regeneration of the organic extractant was achieved by back extraction into an aqueous phase containing NaOH and ethanol. A cleaning protocol consisting of flushing the hydrolysate compartment with NaOH and the organic phase compartment with pure organic phase enabled regeneration and reuse of the module. Ethanol yields from hydrolysates detoxified by membrane extraction using 15% Alamine 336 in oleyl alcohol were about 10% higher than those from hydrolysates detoxified using ammonium hydroxide treatment.

Grzenia, D. L.; Schell, D. J.; Wickramasinghe, S. R.

2012-05-01

271

Membrane tethering  

PubMed Central

Membrane trafficking depends on transport vesicles and carriers docking and fusing with the target organelle for the delivery of cargo. Membrane tethers and small guanosine triphosphatases (GTPases) mediate the docking of transport vesicles/carriers to enhance the efficiency of the subsequent SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor)-mediated fusion event with the target membrane bilayer. Different classes of membrane tethers and their specific intracellular location throughout the endomembrane system are now well defined. Recent biochemical and structural studies have led to a deeper understanding of the mechanism by which membrane tethers mediate docking of membrane carriers as well as an appreciation of the role of tethers in coordinating the correct SNARE complex and in regulating the organization of membrane compartments. This review will summarize the properties and roles of membrane tethers of both secretory and endocytic systems. PMID:25343031

Chia, Pei Zhi Cheryl

2014-01-01

272

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

Gary McCallister

2009-09-01

273

Multiple forms with glucose 6-phosphate dehydrogenase activity in Musca domestica L. as revealed by electrophoresis on cellulose acetate gel.  

PubMed

Single newly emerged males of Musca domestica, WHO strain, usually show five electrophoretic bands of glucose 6-phosphate dehydrogenase (G6PD) activity. Of these five molecular forms, designated with Roman numerals in order from the origin, we have considered the first three: these have been characterized with respect to their substrate and coenzyme specificity and to their sensitivity to some sulfhydryl inhibitors. The data show band III to be G6P specific, nicotinamide adenine dinucleotide phosphate dependent and to be a type I enzyme according to Kamada and Hori's classification. Bands I and II, on the other hand, show wide substrate specificity and low sensitivity to the sulfhydryl inhibitors assayed. In addition, in the absence of an exogenous substrate and in the presence of nicotinamide adenine dinucleotide as a coenzyme, fairly weak bands, which can be ascribed to the so called "nothing dehydrogenase" effect, are seen in the position I and II. Nevertheless, the data reported do not allow a clear definition of the enzymatic type corresponding to bands I and II of G6PD activity. PMID:31398

Cima, L; Malacrida, A; Gasperi, G; Sacchi, L; Grigolo, A

1978-10-01

274

T and B Lymphocytes: Striking Differences in Surface Membranes  

PubMed Central

Lymphocytes can be separated by electrophoresis into cells of high and of low electrophoretic mobility. Cells of high mobility are T cells and those of low mobility are B cells, with distinct immunological functions. Biophysical and biochemical studies on physically isolated and immunologically defined T and B cells in CBA mice showed striking differences in the chemical composition of the surface membranes. PMID:4544817

Mehrishi, J. N.; Zeiller, K.

1974-01-01

275

Investigations of the inhibitory effects of tocopherol (vitamin E) on free radical deterioration of cellular membranes  

NASA Technical Reports Server (NTRS)

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.

Richardson, D.

1975-01-01

276

Activating membranes.  

PubMed

We present a general dynamical theory of a membrane coupled to an actin cortex containing polymerizing filaments with active stresses and currents, and demonstrate that active membrane dynamics [S. Ramaswamy et al., Phys. Rev. Lett. 84, 3494 (2000)] and spontaneous shape oscillations emerge from this description. We also consider membrane instabilities and patterns induced by the presence of filaments with polar orientational correlations in the tangent plane of the membrane. The dynamical features we predict should be seen in a variety of cellular contexts involving the dynamics of the membrane-cytoskeleton composite and cytoskeletal extracts coupled to synthetic vesicles. PMID:25014831

Maitra, Ananyo; Srivastava, Pragya; Rao, Madan; Ramaswamy, Sriram

2014-06-27

277

Antimicrobial electrospun nanofibers of cellulose acetate and polyester urethane composite for wound dressing.  

PubMed

In this study, a series of nanofibrous membranes were prepared from cellulose acetate (CA) and polyester urethane (PEU) using coelectrospinning or blend-electrospinning. The drug release, in vitro antimicrobial activity and in vivo wound healing performance of the nanofiber membranes were evaluated for use as wound dressings. To prevent common clinical infections, an antimicrobial agent, polyhexamethylene biguanide (PHMB) was incorporated into the electrospun fibers. The presence of CA in the nanofiber membrane improved its hydrophilicity and permeability to air and moisture. CA fibers became slightly swollen upon contacting with liquid phase. CA not only increased the liquid uptake but also created a moist environment for the wound, which accelerated wound recovery. PHMB release dynamics of the membranes was controlled by the structure and component ratios of the membranes. The lower ratio of CA: PEU helped to preserve the physical and thermal properties of the membranes, and also reduced the burst release effectively and slowed down diffusion of PHMB during in vitro tests. The controlled-diffusion membranes exerted long-term antimicrobial effect for wound healing. PMID:22692845

Liu, Xin; Lin, Tong; Gao, Yuan; Xu, Zhiguang; Huang, Chen; Yao, Gang; Jiang, Linlin; Tang, Yanwei; Wang, Xungai

2012-08-01

278

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

279

Treatment of Pedophilia with Leuprolide Acetate  

Microsoft Academic Search

To date, the literature on the treatment of individuals who have committed sexual offenses has focused primarily on psychotherapeutic interventions and the use of antiandrogens. Recently case reports and small series supporting the efficacy of other psychiatric medication, such as serotonin reuptake inhibitors, have been published. Only a few publications have looked at the efficacy of leuprolide acetate, an LH-RH

Nancy Raymond; Bean Robinson; Chris Kraft; Barry Rittberg; Eli Coleman

2002-01-01

280

Induction of active immunity with membrane fractions from Haemophilus influenzae type b.  

PubMed Central

Using Escherichia coli strain E-1 as a model, we developed procedures for the preparation of outer- and inner-membrane-enriched fractions as structural units. These procedures could be used to prepare relatively pure inner and outer membrane fractions as determined by succinate dehydrogenase activity, ketodeoxyoctonate levels, and polyacrylamide gradient gel electrophoresis. The use of these procedures to fractionate membrane components from Haemophilus influenzae type b strains H-2 and H-E led to good separation of outer- and inner-membrane-enriched fractions as determined by succinate dehydrogenase and ketodeoxyoctonate levels but incomplete separation as determined by polyacrylamide gradient gel electrophoresis. Although there were differences between the electrophoresis profiles of outer membrane fractions of strains H-2 and H-E, immunization with outer membrane of either strain led to the induction of a high degree of immunoprotection against challenge with the H-2 strain. Protection could also be elicited with inner membrane preparations, but such protection may be due to contamination with outer membrane. Extracted membrane protein induced levels of protection that were comparable to those induced by whole membrane fractions. Images PMID:6602769

Burans, J P; Lynn, M; Solotorovsky, M

1983-01-01

281

Extended length microchannels for high density high throughput electrophoresis systems  

DOEpatents

High throughput electrophoresis systems which provide extended well-to-read distances on smaller substrates, thus compacting the overall systems. The electrophoresis systems utilize a high density array of microchannels for electrophoresis analysis with extended read lengths. The microchannel geometry can be used individually or in conjunction to increase the effective length of a separation channel while minimally impacting the packing density of channels. One embodiment uses sinusoidal microchannels, while another embodiment uses plural microchannels interconnected by a via. The extended channel systems can be applied to virtually any type of channel confined chromatography.

Davidson, James C. (Livermore, CA); Balch, Joseph W. (Livermore, CA)

2000-01-01

282

Compatibility of interspecific Manihot crosses presaged by protein electrophoresis .  

PubMed

Cross incompatibility of wild Manihot species with cassava (M. esculenta) can impede their utilization for improving this cultigen. We tested whether compatibility could be determined based on electrophoresis results. Manihot pilosa, M. glaziovii, M. reptans, and M. cearulescens were tested. These species were allowed to hybridize with cassava to determine whether hybridization coincides with the similarity index based on electrophoresis analysis. Gene markers of leaf shape, stem surface, disk color, and fruit shape were used to confirm hybridization. Manihot pilosa and M. glaziovii successfully hybridized with cassava, while the others failed to do so under natural conditions. This result coincided with the similarity index from electrophoresis. PMID:20092040

Nassar, N M A; Bomfim, N; Chaib, A; Abreu, L F A; Gomes, P T C

2010-01-01

283

A novel approach to pseudopodia proteomics: excimer laser etching, two-dimensional difference gel electrophoresis, and confocal imaging  

PubMed Central

Pseudopodia are actin-rich ventral cellular protrusions shown to facilitate the migration and metastasis of tumor cells. Here, we present a novel approach to perform pseudopodia proteomics. Tumor cells growing on porous membranes extend pseudopodia into the membrane pores. In our method, cell bodies are removed by horizontal ablation at the basal cell surface with the excimer laser while pseudopodia are left in the membrane pores. For protein expression profiling, whole cell and pseudopodia proteins are extracted with a lysis buffer, labeled with highly sensitive fluorescent dyes, and separated by two-dimensional gel electrophoresis. Proteins with unique expression patterns in pseudopodia are identified by mass spectrometry. The effects of the identified proteins on pseudopodia formation are evaluated by measuring the pseudopodia length in cancer cells with genetically modified expression of target proteins using confocal imaging. This protocol allows global identification of pseudopodia proteins and evaluation of their functional significance in pseudopodia formation within one month. PMID:25309719

Mimae, Takahiro; Ito, Akihiko; Hagiyama, Man; Nakanishi, Jun; Hosokawa, Yoichiroh; Okada, Morihito; Murakami, Yoshinori; Kondo, Tadashi

2014-01-01

284

Capillary electrophoresis for total glycosaminoglycan analysis.  

PubMed

A capillary zone electrophoresis-laser-induced fluorescence detection (CZE-LIF) method was developed for the simultaneous analysis of disaccharides derived from heparan sulfate, chondroitin sulfate/dermatan sulfate, hyaluronan, and keratan sulfate. Glycosaminoglycans (GAGs) were first depolymerized with the mixture of GAG lyases (heparinase I, II, III and chondroitinase ABC and chondroitinase AC II) and GAG endohydrolase (keratinase II) and the resulting disaccharides were derivatized by reductive amination with 2-aminoacridone. Nineteen fluorescently labeled disaccharides were separated using 50 mM phosphate buffer (pH 3.3) under reversed polarity at 25 kV. Using these conditions, all the disaccharides examined were baseline separated in less then 25 min. This CZE-LIF method gave good reproducibility for both migration time (?1.03% for intraday and ?4.4% for interday) and the peak area values (?5.6% for intra- and ?8.69% for interday). This CZE-LIF method was used for profiling and quantification of GAG derivative disaccharides in bovine cornea. The results show that the current CZE-LIF method offers fast, simple, sensitive, reproducible determination of disaccharides derived from total GAGs in a single run. PMID:24817364

Ucakturk, Ebru; Cai, Chao; Li, Lingyun; Li, Guoyun; Zhang, Fuming; Linhardt, Robert J

2014-07-01

285

Micro-size polyacrylamide gel electrophoresis system  

NASA Astrophysics Data System (ADS)

The development and characterization of a micro-size two-dimensional polyacrylamide gel electrophoresis system is described. Some of the techniques which have evolved with use of the system are also discussed. This apparatus has unique features which provide advantages over other small scale units. Up to ten first- and second-dimension gels can be processed simultaneously with excellent resolution of protein regions. Consistent reproducibility is possible from protein samples as small as 400 ng and individual protein regions as small as 1 pg can be visualized by silver staining of the two-dimensional gels. Similar sensitivities are achieved in autoradiographs of 3H-labeled proteins extracted from the nuclei of cultured cells. The application of this system in conjunction with flow cytometric examination of nuclear DNA and electrostatic cell sorting of specific cell nuclei to provide homogeneous sample populations, allows subtle variations in isotope incorporation in proteins to be detected; whereas many times in generalized tissue samples these changes are masked. Also, these techniques elucidate the effects of external stimuli (chemicals, drugs, or environment) on protein synthesis and phosphorylation for analyses and comparison. Fabrication drawings are available upon request.

Hinson, W. G.; Pipkin, J. L.; Anson, J. F.; Casciano, D. A.; Burns, E. R.

1987-09-01

286

Analytical instrument qualification in capillary electrophoresis.  

PubMed

Capillary electrophoresis (CE) is a well-established and frequently used technique in the pharmaceutical industry. Therefore an appropriate analytical instrument qualification (AIQ) is required for quality assurance. AIQ forms the basis of a quality management followed by analytical method validation, system suitability tests (SSTs) and quality control checks. Two parts of the AIQ, namely the operational qualification (OQ) and the performance qualification (PQ) are of particular interest in the daily routine of the laboratory. A new concept for OQ and PQ was developed to assure the correct function of a CE system. The significance of each parameter, possible test methods as well as acceptance criteria will be presented and discussed in detail. Especially temperature adjustment by the cooling system and the voltage supply must be tested for accurate and precise operation. The detector noise, wavelength accuracy and detector linearity have to be checked as well. Finally, the injection linearity, accuracy and precision need to be qualified. The proposed set of qualification procedures is easy to implement and was already tested on five CE instruments from three different manufacturers. A time- and cost-saving continuous PQ was derived, using results from method-specific SSTs and some additional experiments. This holistic concept continuously surveys the most relevant parameters, hence assuring the suitability of the used instruments and decreasing their downtimes. PMID:22736350

Cianciulli, Claudia; Wätzig, Hermann

2012-06-01

287

Integrated polymerase chain reaction/electrophoresis instrument  

DOEpatents

A new approach and instrument for field identification of micro-organisms and DNA fragments using a small and disposable device containing integrated polymerase chain reaction (PCR) enzymatic reaction wells, attached capillary electrophoresis (CE) channels, detectors, and read-out all on/in a small hand-held package. The analysis instrument may be made inexpensively, for example, of plastic, and thus is disposable, which minimizes cross contamination and the potential for false positive identification between samples. In addition, it is designed for multiple users with individual applications. The integrated PCR/CE is manufactured by the PCR well and CE channels are "stamped" into plastic depressions where conductive coatings are made in the wells and ends of the CE microchannels to carry voltage and current to heat the PCR reaction mixtures and simultaneously draw DNA bands up the CE channels. Light is transmitted through the instrument at appropriate points and detects PCR bands and identifies DNA fragments by size (retention time) and quantifies each by the amount of light generated as each phototransistor positioned below each CE channel detects a passing band. The instrument is so compact that at least 100 PCR/CE reactions/analyses can be performed easily on one detection device.

Andresen, Brian D. (Livermore, CA)

2000-01-01

288

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

289

Strongly nonlinear waves in capillary electrophoresis  

PubMed Central

In capillary electrophoresis, sample ions migrate along a micro-capillary filled with a background electrolyte under the influence of an applied electric field. If the sample concentration is sufficiently high, the electrical conductivity in the sample zone could differ significantly from the background. Under such conditions, the local migration velocity of sample ions becomes concentration dependent resulting in a nonlinear wave that exhibits shock like features. If the nonlinearity is weak, the sample concentration profile, under certain simplifying assumptions, can be shown to obey Burgers’ equation (S. Ghosal and Z. Chen Bull. Math. Biol. 2010 72(8), pg. 2047) which has an exact analytical solution for arbitrary initial condition. In this paper, we use a numerical method to study the problem in the more general case where the sample concentration is not small in comparison to the concentration of background ions. In the case of low concentrations, the numerical results agree with the weakly nonlinear theory presented earlier, but at high concentrations, the wave evolves in a way that is qualitatively different. PMID:23004798

Chen, Zhen; Ghosal, Sandip

2012-01-01

290

Denaturation and electrophoresis of RNA with glyoxal.  

PubMed

This protocol is used to denature and separate large mRNA molecules (0.5-10 kb) on agarose gels by electrophoretic size fractionation. Glyoxal (also called diformyl or ethanedial), the agent responsible for maintaining denaturation in this protocol, contains two carbonyl groups that react to form a cyclic ring structure with the imino and amino groups of guanine. It can also react with the amino groups of adenine and cytidine. When RNA is denatured in the presence of glyoxal, this covalent adduct prevents normal base pairing and maintains the RNA in a denatured state in agarose gels. Once formed, these adducts are stable at room temperature at pH <7.0; thus, there is no need to add glyoxal to the gel or to the gel buffers to maintain the RNA in the denatured state. Because the fully denatured RNA migrates through agarose gels according to its molecular mass, this method can be used to accurately size mRNA molecules. Following electrophoresis and reversal of glyoxalation, the RNA can be detected using a northern hybridization procedure. PMID:25646499

Rio, Donald C

2015-01-01

291

Contactless conductivity detector array for capillary electrophoresis.  

PubMed

A CE system featuring an array of 16 contactless conductivity detectors was constructed. The detectors were arranged along 70 cm length of a capillary with 100 cm total length and allow the monitoring of separation processes. As the detectors cannot be accommodated on a conventional commercial instrument, a purpose built set-up employing a sequential injection manifold had to be employed for automation of the fluid handling. Conductivity measurements can be considered universal for electrophoresis and thus any changes in ionic composition can be monitored. The progress of the separation of Na(+) and K(+) is demonstrated. The potential of the system to the study of processes in CZE is shown in two examples. The first demonstrates the differences in the developments of peaks originating from a sample plug with a purely aqueous background to that of a plug containing the analyte ions in the buffer. The second example visualizes the opposite migration of cations and anions from a sample plug that had been placed in the middle of the capillary. PMID:24285496

Stojkovic, Marko; Koenka, Israel Joel; Thormann, Wolfgang; Hauser, Peter C

2014-02-01

292

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

293

Phosphorylation of membrane proteins in erythrocytes treated with lead.  

PubMed Central

In immature rat microvessels, endothelial cells and glioma cells, exposure to lead results in an increase in the level of protein kinase C in membranes. In this paper we have extended these studies to human erythrocytes and, in addition, studied the phosphorylation of membrane proteins. A significant increase in the phosphorylation of membrane cytoskeletal proteins of molecular mass 120, 80, 52 and 45 kDa was observed in human erythrocytes treated for 60 min with lead acetate at concentrations greater than 100 nM. These same proteins were phosphorylated when erythrocytes were treated for 10 min with 50 nM phorbol 12-myristate 13-acetate (PMA). Similarly, protein kinase C activity was elevated and an increase in the amount of protein kinase C-alpha was observed in membranes from erythrocytes exposed to concentrations of lead acetate above 100 nM. No changes, however, in the activities of cAMP-dependent protein kinase, protein phosphatases I and IIA or casein kinase were observed. Phosphorylation of these membrane proteins stimulated by lead acetate or by PMA was not observed in erythrocytes depleted of protein kinase C by a 72-h treatment with 500 nM phorbol 12,13-dibutyrate. Finally, no changes in the levels of calcium or diacylglycerol were observed in erythrocytes stimulated with 100 nM lead acetate. These results indicate that, in erythrocytes, lead acetate stimulates the phosphorylation of membrane cytoskeletal proteins by a mechanism dependent on protein kinase C. Since levels of calcium or diacylglycerols did not increase, it appears that lead may activate the enzyme by a direct interaction. PMID:8615806

Belloni-Olivi, L; Annadata, M; Goldstein, G W; Bressler, J P

1996-01-01

294

Detection and immunolocalization of glycoproteins of the plasma membrane of maize sperm cells  

Microsoft Academic Search

Summary After purifying plasma membranes from isolated maize sperm cells by aqueous polymer two-phase partition, peripheral and integral proteins were solubilized from the plasma membrane with Triton X-114 and separated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Silver staining revealed 10 bands (19–68 kDa) of peripheral membrane proteins and about 40 bands (12–120 kDa) of integral proteins. Peroxidase-conjugated Con A

Heng Ping Xu; T. H. Tsao

1997-01-01

295

Multicomponent membranes  

DOEpatents

A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

Kulprathipanja, Santi (Hoffman Estates, IL); Kulkarni, Sudhir S. (Hoffman Estates, IL); Funk, Edward W. (Highland Park, IL)

1988-01-01

296

Recovery of volatile fatty acids via membrane contactor using flat membranes: experimental and theoretical analysis.  

PubMed

Volatile fatty acid (VFA) separation from synthetic VFA solutions and leachate was investigated via the use of a membrane contactor. NaOH was used as a stripping solution to provide constant concentration gradient of VFAs in both sides of a membrane. Mass flux (12.23 g/m(2)h) and selectivity (1.599) observed for acetic acid were significantly higher than those reported in the literature and were observed at feed pH of 3.0, flow rate of 31.5 ± 0.9 mL/min, and stripping solution concentration of 1.0 N. This study revealed that the flow rate, stripping solution strength, and feed pH affect the mass transfer of VFAs through the PTFE membrane. Acetic and propionic acid separation performances observed in the present study provided a cost effective and environmental alternative due to elimination of the use of extractants. PMID:24569043

Tugtas, Adile Evren

2014-07-01

297

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...

298

A model for sample stacking in microcapillary DNA electrophoresis  

E-print Network

Sanger's method of chain termination is the method of choice in DNA sequencing, where electrophoresis is used to separate the different sized DNA. In the past decade, microfabricated capillary devices have been developed ...

Srivastava, Alok Kumar, 1967-

2002-01-01

299

Dna electrophoresis in photopolymerized polyacrylamide gels on a microfluidic device  

E-print Network

DNA gel electrophoresis is a critical analytical step in a wide spectrum of genomic analysis assays. Great efforts have been directed to the development of miniaturized microfluidic systems (“lab-on-a-chip” systems) to perform low-cost, high...

Lo, Chih-Cheng

2009-05-15

300

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

301

Single molecule analysis of DNA electrophoresis in microdevices  

E-print Network

Given that current electrophoresis technology is inadequate for mapping large O[100 kilobasepair] DNA, several promising lab-on-chip designs for DNA mapping have been recently proposed that require either 1) a DNA molecule ...

Randall, Greg C

2006-01-01

302

Integrated Refractive Index Optical Ring Resonator Detector for Capillary Electrophoresis  

E-print Network

Integrated Refractive Index Optical Ring Resonator Detector for Capillary Electrophoresis Hongying Engineering, 240D Life Sciences Center, University of Missouri-Columbia, Columbia, Missouri 65211 a novel miniaturized and multiplexed, on- capillary, refractive index (RI) detector using liquid core

Fan, Xudong "Sherman"

303

Biogas Production through the Syntrophic Acetate-Oxidising Pathway  

E-print Network

retention time OLR Organic loading rate PCR Polymerase chain reaction qPCR Quantitative polymerase chain reaction RNA Ribonucleic acid SAO Syntrophic acetate oxidation SAOB Syntrophic acetate-oxidising bacteria

304

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2013 CFR

... 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. (b) Conditions...

2013-04-01

305

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2011 CFR

... 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. (b) Conditions...

2011-04-01

306

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2012 CFR

... 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. (b) Conditions...

2012-04-01

307

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

308

Gold-catalyzed cyclization of allenyl acetal derivatives  

PubMed Central

Summary The gold-catalyzed transformation of allenyl acetals into 5-alkylidenecyclopent-2-en-1-ones is described. The outcome of our deuterium labeling experiments supports a 1,4-hydride shift of the resulting allyl cationic intermediates because a complete deuterium transfer is observed. We tested the reaction on various acetal substrates bearing a propargyl acetate, giving 4-methoxy-5-alkylidenecyclopent-2-en-1-ones 4 via a degradation of the acetate group at the allyl cation intermediate. PMID:24062838

Vasu, Dhananjayan; Pawar, Samir Kundlik

2013-01-01

309

Isothermal decomposition of ?-irradiated samarium acetate  

NASA Astrophysics Data System (ADS)

Isothermal decomposition of un-irradiated and pre-?-irradiated samarium acetate has been investigated at different temperatures between 613 and 633 K. Irradiation was observed to enhance the rate of decomposition without modifying the mechanism of thermal decomposition. Thermal decomposition of samarium acetate has been shown to proceed by two-dimensional phase-boundary reaction both for un-irradiated and pre-?-irradiated samples. The enhancement of the decomposition was found to increase with an increase in the ?-ray dose applied to the sample and may be attributed to an increase in point defects and formation of additional nucleation centers generated in the host lattice. Thermodynamic values of the main decomposition process were calculated and evaluated.

Mahfouz, R. M.; Monshi, M. A. S.; Alshehri, S. M.; Abd El-Salam, N. M.

2000-10-01

310

Microcoil NMR study of the interactions between doxepin, ?-cyclodextrin, and acetate during capillary isotachophoresis.  

PubMed

The capillary isotachophoresis (cITP) separation of the isomers of the tricyclic antidepressant doxepin using ?-cyclodextrin (?-CD) as a buffer additive is investigated by online microcoil NMR detection. Capillary electrophoresis (CE) is also used to determine the binding constant between the doxepin E and Z geometric isomers and ?-CD. Although the doxepin isomers could be easily baseline resolved by CE, their separation by cITP was more challenging due in part to the high concentration of doxepin after cITP-focusing. The use of online (1)H NMR detection allows observation of changes in doxepin dynamics due to formation of the ?-CD inclusion complex, changes in the fraction complexed and the intracapillary pH. It also provides novel experimental evidence that a weak complex between ?-CD and acetate contributes to its active transport from the leading electrolyte through the sample band to the trailing electrolyte in this cationic cITP separation. The results of these cITP-NMR experiments provide new mechanistic details about the interactions of the buffer counterion acetate with various components of the separation system and have important implications for other analyses based on formation of cyclodextrin inclusion complexes. PMID:22852806

Jones, Christopher J; Larive, Cynthia K

2012-08-21

311

Lithium acetate transformation of yeast Maitreya Dunham August 2004  

E-print Network

Lithium acetate transformation of yeast Maitreya Dunham August 2004 Original protocol from Katja until the OD600 is around 0.7-0.8 (~7 hours). Spin down the cells. Resuspend in 5 ml lithium acetate mix. Spin. Resuspend in 0.5 ml lithium acetate mix. Transfer to an eppendorf tube. Incubate 60 minutes

Dunham, Maitreya

312

Formation of acetic acid from cellulosic substrates by Fusarium oxysporum  

Microsoft Academic Search

Four strains of Fusarium oxysporum and a strain of Monilia brunnae were screened for their ability to convert cellulosic substrates into ethanol\\/acetic acid. These strains were found to utilize cellulose and produce extracellular cellulases. However, only F. oxysporum 841 was found to convert glucose, xylose, and cellulose into ethanol and acetic acid as major end-products under microaerobic conditions. Acetic acid

P. K. R. Kumar; Ajay Singh; K. Schiigerl

1991-01-01

313

Electrophoresis for genotyping: temporal thermal gradient gel electrophoresis for profiling of oligonucleotide dissociation.  

PubMed Central

Traditional use of an oligonucleotide probe to determine genotype depends on perfect base pairing to a single-stranded target which is stable to a higher temperature than when imperfect binding occurs due to a mismatch in the target sequence. Bound oligonucleotide is detected at a predetermined single temperature 'snapshot' of the melting profile, allowing the distinction of perfect from imperfect base pairing. In heterozygotes, the presence of the alternative sequence must be verified with a second oligonucleotide complementary to the variant. Here we describe a system of real-time variable temperature electrophoresis during which the oligonucleotide dissociates from its target. In 20% polyacrylamide the target strand has minimal mobility and released oligonucleotide migrates extremely quickly so that the 'freed' rather than the 'bound' is displayed. The full profile of oligonucleotide dissociation during gel electrophoresis is represented along the gel track, and a single oligonucleotide is sufficient to confirm heterozygosity, since the profile displays two separate peaks. Resolution is great, with use of short track lengths enabling analysis of dense arrays of samples. Each gel track can contain a different target or oligonucleotide and the temperature gradient can accommodate oligonucleotides of different melting temperatures. This provides a convenient system to examine the interaction of many different oligonucleotides and target sequences simultaneously and requires no prior knowledge of the mutant sequence(s) nor of oligonucleotide melting temperatures. The application of the technique is described for screening of a hotspot for mutations in the LDL receptor gene in patients with familial hypercholesterolaemia. Images PMID:7630718

Day, I N; O'Dell, S D; Cash, I D; Humphries, S E; Weavind, G P

1995-01-01

314

Functional Properties of Extruded Starch Acetate Blends  

Microsoft Academic Search

Starch acetate, with degree of substitution of 2, was blended with 0, 7.5 and 15% polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) or Mater-Bi ZF03U (MBI) and 10%, 13%, or 16% (d.b.) ethanol and twin-screw extruded at 160°C barrel temperature. Physical characteristics of the extrudates, such as radial expansion ratio, unit and bulk densities, and of the mechanical properties,

J. Guan; Q. Fang; M. A. Hanna

2004-01-01

315

Acetic acid bacteria as enantioselective biocatalysts  

Microsoft Academic Search

Acetic acid bacteria (five strains of Acetobacter and five strains of Gluconobacter) were used for the biotransformation of different primary alcohols (2-chloropropanol and 2-phenylpropanol) and diols (1,3-butandiol, 1,4-nonandiol and 2,3-butandiol). Most of the tested strains efficiently oxidized the substrates. 2-Chloropropanol and 1,3-butandiol were oxidized with good rates and low enantioselectivity (enantiomeric excess=18–46% of the S-acid), while microbial oxidation of 2-phenylpropanol

A Romano; R Gandolfi; P Nitti; M Rollini; F Molinari

2002-01-01

316

Nonenzymatic phosphorylation of acetate by carbamyl phosphate  

NASA Astrophysics Data System (ADS)

It is found that carbamyl phosphate is an efficient condensing agent for acetate and hydroxylamine in the presence of Be2+ and Al3+. The reaction has an optimum at pH 4 and is completed within 30 min. The yield of hydroxamate formation reaches 30% (based on initial carbamyl phosphate). Acetylphosphate as the intermediary product of this reaction was identified by P-NMR spectroscopy.

Saygin, Ömer

1983-03-01

317

Resistance of Streptococcus bovis to acetic acid at low pH: Relationship between intracellular pH and anion accumulation  

SciTech Connect

Streptococcus bovis JB1, an acid-tolerant ruminal bacterium, was able to grown at pHs from 6.7 to 4.5, and 100 mM acetate had little effect on growth rate or proton motive force across the cell membrane. When S. bovis was grown in glucose-limited chemostats at pH 5.2, the addition of sodium acetate (as much as 100 mM) had little effect on the production of bacterial protein. At higher concentrations of sodium acetate (100 to 360 mM), production of bacterial protein declined, but this decrease could largely be explained by a shift in fermentation products (acetate, formate, and ethanol production to lactate production) and a decline in ATP production (3 ATP per glucose versus 2 ATP per glucose). Y{sub ATP} (grams of cells per mole at ATP) was not decreased significantly even by high concentrations of acetate. Cultures supplemented with 100 mM sodium acetate took up ({sup 14}C)acetate and ({sup 14}C)benzoate in accordance with the Henderson-Hasselbalch equation and gave similar estimates of intracellular pH. As the extracellular pH declined, S. bovis allowed its intracellular pH to decrease and maintained a relatively constant pH gradient across the cell membrane (0.9 unit). The decrease in intracellular pH prevented S. bovis from accumulating large amounts of acetate anion. On the basis of these results it did not appear that acetate was acting as an uncoupler. The sensitivity of other bacteria to volatile fatty acids at low pH is explained most easily by a high transmembrane pH gradient and anion accumulation.

Russell, J.B. (Cornell Univ., Ithaca, NY (USA))

1991-01-01

318

Capillary electrophoresis analysis of glucooligosaccharide regioisomers.  

PubMed

Complex gluco-oligosaccharide mixtures of two regioisomer series were successfully separated by CE. The gluco-oligosaccharide series were synthesized, employing a dextransucrase from Leuconostoc mesenteroides NRRL B-512F, by successive glucopyranosyl transfers from sucrose to the acceptor glucose or maltose. The glucosyl transfer to both acceptors, occurring through the formation of alpha1-->6 linkages, differed for the two series only in the glucosidic bond to the reducing end namely alpha1-->6 or alpha1-->4 bond for glucose or maltose acceptor, respectively. Thus, the combination of the two series results in mixed pairs of gluco-oligosaccharide regioisomers with different degrees of polymerization (DP). These regioisomer series were first derivatized by reductive amination with 9-aminopyrene-1,4,6-trisulfonate (APTS). Under acidic conditions using triethyl ammonium acetate as electrolyte, the APTS-gluco-oligosaccharides of each series were separated enabling unambiguous size determination by coupling CE to electrospray-mass spectrometry. However, neither these acidic conditions nor alkaline buffer systems could be adapted for the separation of the gluco-oligosaccharide regioisomers arising from the two combined series. By contrast, increased resolution was observed in an alkaline borate buffer, using differential complexation of the regioisomers with the borate anions. Such conditions were also successfully applied to the separation of glucodisaccharide regioisomers composed of alpha1-->2, alpha1-->3, alpha1-->4, and alpha1-->6 linkages commonly synthesized by glucansucrase enzymes. PMID:15004847

Joucla, Gilles; Brando, Thérèse; Remaud-Simeon, Magali; Monsan, Pierre; Puzo, Germain

2004-03-01

319

Evaluation of a novel hydrophilic derivatized capillary for protein analysis by capillary electrophoresis-electrospray mass spectrometry.  

PubMed

A new type of hydrophilic derivatized capillary has been used to enable the on-line capillary electrophoresis separation and electrospray mass spectrometric detection of a mixture of proteins containing bovine cytochrome c, tuna cytochrome c and horse heart myoglobin. Less than 40 fmol of each compound were loaded into the capillary. Baseline resolution of components was achieved, as were accurate assignments of molecular masses. The hydrophilic derivatized capillaries were taken through extensive testing procedures to characterize their performance and capabilities for protein analysis. A mixture of six proteins (cytochrome c, ribonuclease A, alpha-chymotrypsinogen, myoglobin, carbonic anhydrase II and alpha-lactalbumin) in acetic acid-sodium acetate buffer was used to delineate the relationships between migration time and pH, along with migration time and buffer concentration for each protein. The variations in capillary efficiency as a function of pH and as a function of buffer concentration were also characterized for the same six proteins in the acetic acid-sodium acetate system. A pH of 4.8 was found to offer an excellent compromise between separation efficiency (up to 500,000 theoretical plates) and analysis time. Capillary efficiencies were also found to be very good when employing a Tris.HCl electrolyte adjusted to pH 4.8. Lastly, electropherogram reproducibility and capillary durability were examined with the finding that little deterioration of the capillary occurred over the course of 400 injections (200 h run time). This represents a notable improvement over previously documented derivatization procedures designed to reduce protein adsorption to fused-silica capillary walls. PMID:7981821

Cole, R B; Varghese, J; McCormick, R M; Kadlecek, D

1994-10-01

320

Effect of ethyl acetate on carbohydrate components and crystalline structure of pulp produced in aqueous acetic acid pulping  

Microsoft Academic Search

The aim of this study was to investigate the changes in carbohydrate components and the crystalline structure in hemp bast\\u000a fibers by adding ethyl acetate to acetic acid\\/water pulping processes. It was found that ethyl acetate added to acetic acid\\/water\\u000a process had a positive effect on yield, viscosity and carbohydrate components in pulp. It was assumed that the delignification\\u000a ratio

Esat Gümü?kaya; Mustafa Usta; Mualla Balaban Uçar

2009-01-01

321

Amphiphilic Membranes  

E-print Network

Contents: 1. Introduction 2. Amphiphilic molecules and the phases they form 3. Isolated membranes: the Helfrich hamiltonian 4. Vesicle shapes 5. Shape fluctuations in vesicles 6. Interacting fluid membranes 7. Conclusions A. Differential equations for vesicle shapes B. The Faddeev-Popov determinant C. One-loop calculation of the renormalization group D. The Liouville model

Luca Peliti

1995-01-17

322

Shotgun proteomics of plant plasma membrane and microdomain proteins using nano-LC-MS/MS.  

PubMed

Shotgun proteomics allows the comprehensive analysis of proteins extracted from plant cells, subcellular organelles, and membranes. Previously, two-dimensional gel electrophoresis-based proteomics was used for mass spectrometric analysis of plasma membrane proteins. In order to get comprehensive proteome profiles of the plasma membrane including highly hydrophobic proteins with a number of transmembrane domains, a mass spectrometry-based shotgun proteomics method using nano-LC-MS/MS for proteins from the plasma membrane proteins and plasma membrane microdomain fraction is described. The results obtained are easily applicable to label-free protein semiquantification. PMID:24136542

Takahashi, Daisuke; Li, Bin; Nakayama, Takato; Kawamura, Yukio; Uemura, Matsuo

2014-01-01

323

Evidence for a transition state analog, MgADP-aluminum fluoride-acetate, in acetate kinase from Methanosarcina thermophila.  

PubMed

Aluminum fluoride has become an important tool for investigating the mechanism of phosphoryl transfer, an essential reaction that controls a host of vital cell functions. Planar AlF(3) or AlF(4)(-) molecules are proposed to mimic the phosphoryl group in the catalytic transition state. Acetate kinase catalyzes phosphoryl transfer of the ATP gamma-phosphate to acetate. Here we describe the inhibition of acetate kinase from Methanosarcina thermophila by preincubation with MgCl(2), ADP, AlCl(3), NaF, and acetate. Preincubation with butyrate in place of acetate did not significantly inhibit the enzyme. Several NTPs can substitute for ATP in the reaction, and the corresponding NDPs, in conjunction with MgCl(2), AlCl(3), NaF, and acetate, inhibit acetate kinase activity. Fluorescence quenching experiments indicated an increase in binding affinity of acetate kinase for MgADP in the presence of AlCl(3), NaF, and acetate. These and other characteristics of the inhibition indicate that the transition state analog, MgADP-aluminum fluoride-acetate, forms an abortive complex in the active site. The protection from inhibition by a non-hydrolyzable ATP analog or acetylphosphate, in conjunction with the strict dependence of inhibition on the presence of both ADP and acetate, supports a direct in-line mechanism for acetate kinase. PMID:11960978

Miles, Rebecca D; Gorrell, Andrea; Ferry, James G

2002-06-21

324

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

325

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 said smino groups contained on the surface thereof. 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 said 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 membrances may be reprobed numerous times.

Caldwell, Karin D. (Salt Lake City, UT); Chu, Tun-Jen (Salt Lake City, UT); Pitt, William G. (Orem, UT)

1992-01-01

326

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. PMID:20665910

Felhofer, Jessica L.; Blanes, Lucas; Garcia, Carlos D.

2010-01-01

327

Crystalline Membranes  

NASA Technical Reports Server (NTRS)

In certain aspects, the invention features methods for forming crystalline membranes (e.g., a membrane of a framework material, such as a zeolite) by inducing secondary growth in a layer of oriented seed crystals. The rate of growth of the seed crystals in the plane of the substrate is controlled to be comparable to the rate of growth out of the plane. As a result, a crystalline membrane can form a substantially continuous layer including grains of uniform crystallographic orientation that extend through the depth of the layer.

Tsapatsis, Michael (Inventor); Lai, Zhiping (Inventor)

2008-01-01

328

Transport of auxin (indoleacetic acid) through lipid bilayer membranes  

Microsoft Academic Search

Summary Diffusion of auxin (indole-3-acetic acid) through planar lipid bilayer membranes was studied as a function of pH and auxin concentration. Membranes were made of egg or soybean lecithin or phosphatidyl serine inn-decane (25–35 mg\\/ml). Tracer and electrical techniques were used to estimate the permeabilities to nonionized (HA) and ionized (A-) auxin. The auxin tracer flux is unstirred layer limited

John Gutknecht; Anne Walter

1980-01-01

329

Measuring the zeta (electrokinetic) potential of reverse osmosis membranes by a streaming potential analyzer  

Microsoft Academic Search

SUMMARY The use of a novel streaming potential analyzer to measure the zeta potential of cellulose acetate and composite polyamide reverse osmosis membranes is reported. Zeta potentials of these membranes were measured at various solution chemistries. These include effects of salt (NaCl) concentration, solution pH, and the presence of dissolved humic substances. It is demonstrated that streaming potential is a

Menachem Elimelech; William H. Chen; John J. Waypa

1994-01-01

330

Membrane Rafts  

NSDL National Science Digital Library

The main focus of this three part series is to explore the concept of "Membrane Rafts". In the first part, we will examine what is popularly understood by the term "Membrane Raft" and ask why this concept was proposed in the first place. With a focus on the study of the characteristics of a popular "raft-marker", a class of cell surface lipid-tethered proteins, the GPI-anchored proteins.

Satyajit 'Jitu' Mayor (Cellular Organisation and Signalling, National Centre for Biological Sciences, Bangalore, India;)

2007-05-01

331

THERMAL DETECTION OF DNA AND PROTEINS DURING GEL ELECTROPHORESIS  

SciTech Connect

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to try to detect unstained, untagged, unlabeled DNA bands in real-time during gel electrophoresis using simple thermal measurements. The technical and ES&H advantages to this approach could potentially be quite significant, especially given the extreme importance of gel electrophoresis to a wide variety of practical and research fields. The project was unable to demonstrate sufficient thermal sensitivity to detect DNA bands. It is clear that we still do not understand the gel electrophoresis phenomenon very well. The temperature control techniques developed during the course of this project have other useful applications.

R. JOHNSTON

2000-08-01

332

Analysis of Common Household Cleaner-Disinfectants by Capillary Electrophoresis  

NASA Astrophysics Data System (ADS)

The use of capillary electrophoresis (CE) as an analytical technique in research, industrial, and commercial laboratories is growing rapidly. It is therefore very important to expose undergraduate instrumental analysis students to capillary electrophoresis. In this report we describe the CE analysis for benzalkonium compounds in common household cleaners and disinfectants. The surfactant nature of the benzalkonium compounds is the key consideration in performing the analysis, and modifications to the CE running buffer must be performed in order to successfully analyze the products. This experiment also illustrates the importance of (i) using peak areas corrected for variations in migration time to improve accuracy and (ii) using internal standards to improve the precision of capillary electrophoresis results.

Gardner, William P.; Girard, James E.

2000-10-01

333

Chiral recognition of dapoxetine enantiomers with methylated-gamma-cyclodextrin: a validated capillary electrophoresis method.  

PubMed

The enantiomers of dapoxetine, a serotonin transporter inhibitor for the treatment of premature ejaculation have been separated by cyclodextrin modified capillary zone electrophoresis using uncoated fused-silica capillary. Over 20 cyclodextrins were screened as chiral selectors, investigating the stability of the inclusion complexes and enantioseparating properties. According to the preliminary experiments as chiral selector randomly methylated-?-cyclodextrin was chosen. The basic chemical and instrumental parameters of enantioseparation as concentration of buffer, chiral selector and organic additive, pH, temperature and applied voltage were optimized afterwards using an orthogonal experimental design. Using this methodology not only the optimal parameter values for chiral separation (15 °C, +15 kV, 70 mM acetate, 20 v/v% MeOH, pH*=4.5, 3 mM methylated-?-CyD) but also the significance order of factors on resolution was determined. Applying these parameters an optimal resolution of 7.01 was achieved. The optimized method was then validated according to the ICH guideline Q2 (R1) with regard to repeatability, linearity range, LOD, LOQ, accuracy and robustness. PMID:22280959

Neumajer, Gábor; Sohajda, Tamás; Darcsi, András; Tóth, Gerg?; Szente, Lajos; Noszál, Béla; Béni, Szabolcs

2012-03-25

334

Chiral separation of cathinone derivatives used as recreational drugs by cyclodextrin-modified capillary electrophoresis.  

PubMed

In recent years, cathinone derivatives have entered the global drug market and caused serious social problems in many European countries. Modification of the basic structure of cathinone leads to a multitude of derivatives, including the most popular representative mephedrone. All those substances contain a stereogenic center and therefore two isoforms exist. As it is the case with many chiral active pharmaceutical ingredients, even the pharmacological effect of the enantiomers of those psychoactive compounds may differ. During this research, an easy-to-prepare chiral capillary zone electrophoresis method for the enantioseparation of a set of 19 cathinone derivatives was developed. Testing different types of cyclodextrin (CD), including native-?-CD, carboxymethyl-?-CD, 2-hydroxypropyl-?-CD, sulfated-?-CD, and native ?-CD, best results were obtained with the negatively charged sulfated-?-CD. The effect of the CD concentration, the temperature, and the addition of ACN to the BGE on the enantioseparation is shown by three model compounds. Under optimal conditions, using 20 mg/mL sulfated-?-CD in 50 mM ammonium acetate buffer pH = 4.5 containing 10% v/v ACN at a cassette temperature of 40°C and with an applied voltage of 20 kV, all derivatives except methedrone were resolved in their enantiomers within 20 min. PMID:22736365

Mohr, Stefan; Pilaj, Stefan; Schmid, Martin G

2012-06-01

335

Bacterial community dynamics of salted and fermented shrimp based on denaturing gradient gel electrophoresis.  

PubMed

The Korean traditional seafood jeotgal is consumed directly or as an additive in other foods to improve flavor or fermentation efficiency. Saeujot, made from salted and fermented tiny shrimp (SFS; Acetes japonicus), is the best-selling jeotgal in Korea. In this study, we reveal the microbial diversity and dynamics in naturally fermented shrimp by denaturing gradient gel electrophoresis (DGGE). The population fingerprints of the predominant microbiota and its succession were generated by DGGE analysis of universal V3 16S rDNA polymerase chain reaction (PCR) amplicons. Overall, 17 strains were identified from sequencing of 30 DGGE bands. The DGGE profiles showed diverse bacterial populations in the sample, throughout the fermentation of SFS. Staphylococcus equorum, Halanaerobium saccharolyticum, Salimicrobium luteum, and Halomonas jeotgali were the dominant bacteria, and their levels steadily increased during the fermentation process. Certain other bacteria, such as Psychrobacter jeotgali and Halomonas alimentaria appeared during the early-fermentation process, while Alkalibacterium putridalgicola, Tetragenococcus muriaticus, and Salinicoccus jeotgali appeared during the late-fermentation process. The members of the order Bacillales were found to be predominant during the fermentation of SFS. Furthermore, S. equorum was identified as the dominant bacterial isolate by the traditional method of culturing under aerobic and facultative anaerobic conditions. We expect that this information will facilitate the design of autochthonous starter cultures for the production of SFS with desired characteristic sensory profiles and shorter ripening times. PMID:25393163

Han, Kook-Il; Kim, Yong Hyun; Hwang, Seon Gu; Jung, Eui-Gil; Patnaik, Bharat Bhusan; Han, Yeon Soo; Nam, Kung-Woo; Kim, Wan-Jong; Han, Man-Deuk

2014-12-01

336

A novel buffer system for separation of metal cations by capillary electrophoresis with indirect UV detection.  

PubMed

Generally, the buffers used for metal ion separations in capillary electrophoresis (CE) consist of a UV-active substance, pH-adjuster, and weak complexing reagent. This paper describes the successful separation of metal ions with a new buffer that contains no complexing reagent. Of several weakly basic compounds tested, 2-aminopyridine was selected as the most useful UV-active substance. It was used at a concentration of 15 mM with pH adjusted to 5.0 +/- 0.1 by acetic acid. The degree of protonation of the UV-active substance played an important role in detection. The stacking phenomenon was a significant contributor to efficiency in this buffer system, and water-diluted samples gave especially high efficiencies. When a 75-micron-i.d. fused-silica capillary was used, a separation efficiency of 1.8 x 10(5) was observed. Quantitative determinations of Ca2+, Mn2+, Zn2+, and Cd2+ were achieved with good linear calibration curves over the range of concentration from a few milligrams per liter to 100 mg/L. The detection limits were 0.2 mg/L for Ca2+, 0.4 mg/L for Mn2+ and Zn2+, and 0.6 mg/L for Cd2+, based on three times the baseline noise. PMID:9384787

Cheng, K; Nordmeyer, F R; Lamb, J D

1995-01-01

337

Immunotoxicity of trenbolone acetate in Japanese quail  

USGS Publications Warehouse

Trenbolone acetate is a synthetic androgen that is currently used as a growth promoter in many meat-exporting countries. Despite industry laboratories classifying trenbolone as nonteratogenic, data showed that embryonic exposure to this androgenic chemical altered development of the immune system in Japanese quail. Trenbolone is lipophilic, persistent, and released into the environment in manure used as soil fertilizer. This is the first study to date to assess this chemical's immunotoxic effects in an avian species. A one-time injection of trenbolone into yolks was administered to mimic maternal deposition, and subsequent effects on the development and function of the immune system were determined in chicks and adults. Development of the bursa of Fabricius, an organ responsible for development of the humoral arm of the immune system, was disrupted, as indicated by lower masse, and smaller and fewer follicles at day 1 of hatch. Morphological differences in the bursas persisted in adults, although no differences in either two measures of immune function were observed. Total numbers of circulating leukocytes were reduced and heterophil-lymphocyte ratios were elevated in chicks but not adults. This study shows that trenbolone acetate is teratogenic and immunotoxic in Japanese quail, and provides evidence that the quail immune system may be fairly resilient to embryonic endocrine-disrupting chemical-induced alterations following no further exposure posthatch.

Quinn, M.J.; McKernan, M.; Lavoie, E.T.; Ottinger, M.A.

2007-01-01

338

Atmospheric formic and acetic acids in Venezuela  

NASA Astrophysics Data System (ADS)

Gas, phase and rain concentrations of HCOOH and CH 3COOH have been measured at various sites in the savannah climatic region, a cloud forest site and a coastal site in Venezuela. Gas phase and rain water were sampled using the aqueous scrubber technique and a wet only collector, respectively. Analyses were made by ion chromatography. The results indicate that formic and acetic acids are important components of the Venezuelan atmosphere. They are homogeneously distributed, suggesting a widespread source. Boundary layer concentrations during the dry season (HCOOH, 1.8 ppbv; CH 3COOH, 1.25 ppbv) are higher than in the wet season (HCOOH, 1.0 ppbv; CH 3COOH, 0.7 ppbv), mainly due to a longer lifetime of the acid during the dry season (˜6 days) compared with the wet season (˜2 days). The overall concentrations in rain are 7.0 and 4.0 ?M for formic and acetic acids, respectively. The estimated annual total depositions are: HCOOH, 17 mmol m -2 yr -1 and CH 3COOH,10 mmol m -2 yr -1; around half of the acids are removed by dry deposition. It is established that a larger source (˜1.8 times) of both acids is present during the wet season. We speculate that atmospheric oxidation of hydrocarbons should be the main source of HCOOH and CH 3COOH in the Venezuelan atmosphere; soil emissions could make a significant contribution during the dry season.

Sanhueza, Eugenio; Figueroa, Luis; Santana, Magaly

339

Replaceable polymers in DNA sequencing by capillary electrophoresis.  

PubMed

Much progress has been made in the development of replaceable sieving polymers and capillary coatings for high-performance DNA sequencing by capillary electrophoresis. Several studies of parameters that affect resolution, read length and reproducibility have begun to reveal the physical mechanisms acting on single-stranded DNA during electrophoresis through semidilute polymer solutions. Recently developed electro-osmosis-inhibiting matrix polymers have simplified the process of coating capillaries, facilitating the automation of high-throughput parallel systems for large-scale sequencing. PMID:9013653

Quesada, M A

1997-02-01

340

Gel Electrophoresis of Gold-DNA Nano-Conjugates  

SciTech Connect

Single stranded DNA of different lengths and different amounts was attached to colloidal phosphine stabilized Au nanoparticles. The resulting conjugates were investigated in detail by a gel electrophoresis study based on 1200 gels. We demonstrate how these experiments help to understand the binding of DNA to Au particles. In particular we compare specific attachment of DNA via gold-thiol bonds with nonspecific adsorption of DNA. The maximum number of DNA molecules that can be bound per particle was determined. We also compare several methods to used gel electrophoresis for investigating the effective diameter of DNA-Au conjugates, such as using a calibration curve of particles with known diameters and Ferguson plots.

Pellegrino, T.; Sperling, R.A.; Alivisatos, A.P.; Parak, W.J.

2006-01-10

341

An enzymatically driven membrane reconstitution from solubilized components  

PubMed Central

Acyltransferase activity is present in a variety of membranes species, including liver microsomes. The substrates of this enzyme are lysophosphatides and acyl CoA derivatives. We have found that the detergent effect of these substrates can be used to solubilize rat liver microsomes. If the solubilized fraction in incubated, the acyltransferase acylates the lysophosphatide and thereby degrades the detergent effect so that vesicular membranes re-form. Gel electrophoresis patterns show that the reconstituted membranes contain all of the major protein components of the original microsomes. A marker enzyme for liver microsomes, NADPH-cytochrome c reductase, was present in the reconstituted membranes at 70% of the specific activity in the original microsomes, and freeze-fracture electron microscopy showed intramembrane particles on all fracture faces. The system may provide a useful model for studies particles on all fracture faces. This system may provide a useful model for studies of certain membrane biogenesis reactions that utilize acyltransferase in vivo. PMID:6769929

1980-01-01

342

Preparation of pervaporation membranes. Final report on Phase 1. Report for 1 January-31 October 1989  

SciTech Connect

The goal of the Phase 1 program was to prepare improved pervaporation membranes for the separation of polar solvents from water. Membranes were prepared from modified polysiloxanes and other rubbery materials. These membranes were tested with ethanol/water and ethyl acetate/water mixtures to determine their performance in a pervaporation test loop. Polydimethylsiloxane with polyamide blocks was the most selective material for ethanol/water separation. Polybutadiene membranes were preferred for ethyl acetate/water separation. The performance of the polydimethysiloxane-polyamide block copolymer demonstrates that the inclusion of hydrophilic groups into polydimethylsiloxane increases the ethanol/water selectivity, but the improvement is not significant. Testing of polyvinylmethylsiloxane membranes indicated that the degree of cross-linking in a polysiloxane membrane has a significant effect on ethanol/water selectivity. A highly cross-linked siloxane has a much lower ethanol/water selectivity than a less cross-linked material.

Baker, R.W.; Athayede, A.L.; Castro, R.

1989-10-15

343

Crystal structure and chemical bonding in tin(II) acetate  

Microsoft Academic Search

Tin(II) acetate was prepared and its crystal structure was solved from X-ray powder diffraction data. Tin(II) acetate adopts a polymeric structure consisting of infinite Sn(CH3COO)2 chains running along the c-axis which are packed into groups of four. The acetate groups bridge the Sn atoms along the chains. The Sn atoms are asymmetrically surrounded by four oxygen atoms with two short

Varvara S. Stafeeva; Alexander S. Mitiaev; Artem M. Abakumov; Alexander A. Tsirlin; Artem M. Makarevich; Evgeny V. Antipov

2007-01-01

344

The acetate kinase of Clostridum acetobutylicum strain P262  

Microsoft Academic Search

Clostridum acetobutylicum strain P262 fermented glucose, pyruvate, or lactate, and the butyrate production was substrate-dependent. Differences in butyrate yield could not be explained by changes in butyrate kinase activities, but the butyrate production was inversely related to acetate kinase activity. The acetate kinase had a pH optimum of 8.0, aKm for acetate of 160 mM, and akcat of 16,800 min-1.

Francisco Diez-Gonzalez; James B. Russell; Jean B. Hunter

1996-01-01

345

Mesophilic syntrophic acetate oxidation during methane formation in biogas reactors  

Microsoft Academic Search

The reaction pathway for the formation of methane from acetate was investigated in sludge from 13 different biogas reactors. By following the conversion of [2-14C]acetate and [14C]bicarbonate it was shown that methane formation by syntrophic acetate oxidation was the dominating mechanism for acetotrophic methanogenesis in sludge containing high levels of salts, mainly ammonium, and volatile fatty acids. In one biogas

Anna Schnürer; Gerhard Zellner; Bo H. Svensson

1999-01-01

346

Effect of iodination on human growth hormone and prolactin: characterized by bioassay, radioimmunoassay, radioreceptor assay, and electrophoresis  

SciTech Connect

Human GH (hGH) and PRL (hPRL) were iodinated using lactoperoxidase. The iodinated hormones were characterized by RIA, radioreceptor assay (RRA), and bioassay (BA) using the Nb2 Node lymphoma cell line. The proportion of tracer that could bind to rat liver membranes or rabbit antibodies was determined, and the distribution of iodinated hormones was examined using polyacrylamide gel electrophoresis. Excess antibody was capable of precipitating 87.9% of the radioactivity associated with the hGH tracer and 86.0% of the hPRL tracer. The maximal specific binding to a liver membrane preparation averaged 67.3% of the (/sup 125/I)iodo-hGH radioactivity and 48.8% of the (/sup 125/I)iodo-hPRL radioactivity. The respective BA and RRA activity estimates for (/sup 125/)iodo-hGH averaged 90% and 114% of the activity measured by the RIA. For (/sup 125/I)iodo-hPRL, the values were 75% by BA and 68% by RRA. The bioactivity profiles of iodinated hGH and hPRL shifted anodally on polyacrylamide gel electrophoresis in comparison to the bioactivity distribution of the respective uniodinated hormones. Iodine incorporation rather than oxidation appeared to be responsible for the shift. After electrophoresis, all eluates which contained significant radioactivity were active in the BA and RIA. Furthermore, specific activities calculated from the bioactive hormone and radioactivity in each electrophoretic segment agreed well with the average specific activity estimated from the amount of iodine incorporated into the protein peak upon gel filtration. These data suggest that hGH and hPRL to a major degree retain biological integrity after iodination.

Hughes, J.P. (Univ. of Manitoba, Winnipeg, Canada); Tanaka, T.; Gout, P.W.; Beer, C.T.; Noble, R.L.; Friesen, H.G.

1982-09-01

347

Effect of iodination on human growth hormone and prolactin: characterized by bioassay, radioimmunoassay, radioreceptor assay, and electrophoresis  

SciTech Connect

Human GH (hGH) and PRL (hPRL) were iodinated using lactoperoxidase. The iodinated hormones were characterized by RIA, radioreceptor assay (RRA), and bioassay (BA) using the Nb2 Node lymphoma cell line. The proportion of tracer that could bind to rat liver membranes or rabbit antibodies was determined, and the distribution of iodinated hormones was examined using polyacrylamide gel electrophoresis. Excess antibody was capable of precipitating 87.9% of the radioactivity associated with the hGH tracer and 86.0% of the hPRL tracer. The maximal specific binding to a liver membrane preparation averaged 67.3% of the (/sup 125/I)iodo-hGH radioactivity and 48.8% of the (/sup 125/I)iodo-hPRL radioactivity. The respective BA and RRA activity estimates for (/sup 125/I)iodo-hGH averaged 90% and 114% of the activity measured by the RIA. For (/sup 125/I)iodo-hPRL, the values were 75% by BA and 68% by RRA. The bioactivity profiles of iodinated hGH and hPRL shifted anodally on polyacrylamide gel electrophoresis in comparison to the bioactivity distribution of the respective uniodinated hormones. Iodine incorporation rather than oxidation appeared to be responsible for the shift. After electrophoresis, all eluates which contained significant radioactivity were active in the BA and RIA. Furthermore, specific activities calculated from the bioactive hormone and radioactivity in each electrophoretic segment agreed well with the average specific activity estimated from the amount of iodine incorporated into the protein peak upon gel filtration. These data suggest that hGH and hPRL to a major degree retain biological integrity after iodination.

Hughes, J.P.; Tanaka, T.; Gout, P.W.; Beer, C.T.; Noble, R.L.; Friesen, H.G.

1982-09-01

348

Membrane Permeability  

PubMed Central

The reflection coefficient method for describing volume and solute fluxes through membranes is generalized to take into account the nonideality of the solutions bathing the membrane and/or multicomponent systems. The reflection coefficient of the impermeable species in these systems is less than unity by a coefficient ?. The reflection coefficient obtained solely from the volume flow equation, ?v, will always be less than the reflection coefficient obtained from the solute flow equation, ?8v. These two coefficients are related by ?8v = ?v + ?. PMID:5019478

Zelman, Allen

1972-01-01

349

Polypyrrole based strong acid catalyst for acetalization  

NASA Astrophysics Data System (ADS)

Novel polypyrrole based acid catalyst has been synthesized through the neutralization reaction of polypyrrole and sulfuric acid. The polypyrrole based acid owned the acidity as high as 6.0 mmol/g, which was much higher than that of the traditional solid acids such as Nafion and Amberlyst-15 (0.8 mmol/g). The catalytic activities of the novel solid acid were investigated through the acetalization. The results showed that the novel solid acid held high activities for the reactions. Furthermore, the recycled activities of the catalyst indicated that the solid acid owned high stability during the catalytic process and little acid sites dropped from polypyrrole. The high acidity and stability made the novel polypyrrole based acid hold great potential for the green chemical processes.

Liang, Xuezheng; Cheng, Yuxiao; Qi, Chenze

2011-09-01

350

N-(2-Chloro-acet-yl)glycine.  

PubMed

The title compound, C4H6ClNO3, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In each mol-ecule, there are N-H?O and N-H?Cl hydrogen bonds. Both mol-ecules are relatively planar, with the mean plane of the acetamide [N-C(=O)C] group being inclined to the mean plane of the acetate group [C-C(=O)O] by 9.23?(13)° in mol-ecule A and 6.23?(12)° in mol-ecule B. In the crystal, adjacent mol-ecules are linked by O-H?O hydrogen bonds and weak C-H?O contacts forming -A-A-A- and -B-B-B- parallel chains propagating along the a-axis direction. PMID:24454136

Zhang, Yu-Cheng; Zhang, Xiu-Qin; Wang, Kai; Chen, Qiang

2013-10-26

351

Synthesis and regeneration of lead (IV) acetate  

SciTech Connect

Lead acetate [Pb(O{sub 2}CMe){sub 4}] was easily synthesized from a warm solution of Pb{sub 3}O{sub 4}, HO{sub 2}CMe and O(OCMe){sub 2} following literature preparations when the appropriate measures to minimize water contamination were followed. Furthermore, Pb(O{sub 2}CMe){sub 4} which has been decomposed (evidenced by the appearance of a purple color due to oxidation) can be regenerated using a similar preparatory route. Introduction of Pb(O{sub 2}CMe){sub 4} from the two routes outlined above into the IMO process for production of PZT thin films gave films with comparable ferroelectric properties to commercially available Pb(O{sub 2}CMe){sub 4} precursors. However, the freshly synthesized material yields PZT films with better properties compared to the recycled material.

Boyle, T.J.; Al-Shareef, H.N.; Moore, G.J. [Sandia National Labs., Albuquerque, NM (United States). Advanced Materials Lab.

1996-11-01

352

Solid friction in gel electrophoresis S. F. Burlatskya)  

E-print Network

Solid friction in gel electrophoresis S. F. Burlatskya) and John M. Deutch Department of Chemistry 1995 We study the influence of solid frictional forces acting on polymer chains moving in a random environment. We show that the total reduction in the chain tension resulting from the small friction between

Deutch, John

353

Nanoparticle gel electrophoresis: bare charged spheres in polyelectrolyte hydrogels.  

PubMed

Nanoparticle gel electrophoresis has recently emerged as an attractive means of separating and characterizing nanoparticles. Consequently, a theory that accounts for electroosmotic flow in the gel, and coupling of the nanoparticle and hydrogel electrostatics and hydrodynamics, is required, particularly for gels in which the mesh size is comparable to or smaller than the particle radii. Here, we present an electrokinetic model for charged, spherical colloidal particles undergoing electrophoresis in charged (polyelectrolyte) hydrogels: the gel-electrophoresis analogue of Henry's theory for electrophoresis in Newtonian electrolytes. We compare numerically exact solutions of the model with several independent asymptotic approximations, identifying regions in the parameter space where these approximations are accurate or break down. As previously assumed in the literature, Henry's formula, modified by the addition of a constant electroosmotic flow mobility, is accurate only for nanoparticles that are small compared to the hydrogel mesh size. We derived an exact analytical solution of the full model by judiciously modifying the theory of Allison et al. for uncharged gels, drawing on the superposition methodology of Doane et al. to account for hydrogel charge. This furnishes accurate and economical mobility predictions for the entire parameter space. The present model suggests that nanoparticle size separations (with diameters ?40 nm) are optimal at low ionic strength, with a gel mesh size that is selected according to the particle charging mechanism. For weakly charged particles, optimal size separation is achieved when the Brinkman screening length is matched to the mean particle size. PMID:23153681

Li, Fei; Hill, Reghan J

2013-03-15

354

Silver Staining of 2D Electrophoresis Gels Thierry Rabilloud  

E-print Network

and 10 times higher than colloidal Coomassie Blue. However, the first silver staining protocols wereSilver Staining of 2D Electrophoresis Gels Thierry Rabilloud CEA-DSV-iRTSV/LCBM and UMR CNRS Head: Silver staining #12;i. Abstract Silver staining is used to detect proteins after electrophoretic

Paris-Sud XI, Université de

355

Sample preconcentration with chemical derivatization in capillary electrophoresis  

Microsoft Academic Search

New strategies for integrating sample pretreatment with chemical analyses under a single format is required for rapid, sensitive and enantioselective analyses of low abundance metabolites in complex biological samples. Capillary electrophoresis (CE) offers a unique environment for controlling analyte\\/reagent band dispersion and electromigration properties using discontinuous electrolyte systems. Recent work in our laboratory towards developing a high-throughput CE platform for

Adam S. Ptolemy; Philip Britz-McKibbin

2006-01-01

356

Capillary Electrophoresis of DNA in Uncrosslinked Polymer Solutions  

E-print Network

Capillary Electrophoresis of DNA in Uncrosslinked Polymer Solutions: Evidence for a New Mechanism fused silica capillary filled with an uncrosslinked polymer solution. An early assumption.0-23.1 kbp) can be separated by CE in extremely dilute polymer solutions, which contain as little as 6 parts

Barron, Annelise E.

357

Temperature Effects on Electrophoresis Anita Rogacs and Juan G. Santiago*  

E-print Network

Temperature Effects on Electrophoresis Anita Rogacs and Juan G. Santiago* Department of Mechanical: We present a model capturing the important contributors to the effects of temperature on the observable electrophoretic mobilities of small ions, and on solution conductivity and pH. Our temperature

Santiago, Juan G.

358

Polymerase Chain Reaction (PCR) and Gel Electrophoresis Powerpoint  

NSDL National Science Digital Library

The HURI SURI project is developing a regional biotechnology workforce pipeline by expanding and supporting biotechnology research experiences for Jamestown Community College (JCC) undergraduates and disseminating these research experiences and materials to area high school teachers and students. This 15 slide presentation provides an introduction to DNA and explains polymerase chain reactions and gel electrophoresis. Many diagrams are included to help explain the concepts.

359

Gel Electrophoresis--The Easy Way for Students  

ERIC Educational Resources Information Center

This article describes a simple, inexpensive, easy to conduct gel-electrophoresis activity using food dyes. It is an alternative to the more expensive counterparts which require agarose gel, DNA samples, purchased chamber and Tris-borate-EDTA buffer. We suggest some learning activities for senior biology students along with comments on several…

VanRooy, Wilhelmina; Sultana, Khalida

2010-01-01

360

Capillary electrophoresis application in metal speciation and complexation characterization  

Technology Transfer Automated Retrieval System (TEKTRAN)

Capillary electrophoresis is amenable to the separation of metal ionic species and the characterization of metal-ligand interactions. This book chapter reviews and discusses three representative case studies in applications of CE technology in speciation and reactions of metal with organic molecules...

361

Statistical analysis of denaturing gel electrophoresis (DGE) fingerprinting patterns  

Microsoft Academic Search

Summary Technical developments in molecular biology have found extensive applications in the field of microbial ecology. Among these techniques, fingerprinting methods such as denaturing gel electrophoresis (DGE, including the three options: DGGE, TGGE and TTGE) has been applied to environmental samples over this last decade. Microbial ecologists took advantage of this technique, originally developed for the detection of single mutations,

N. Fromin; J. Hamelin; S. Tarnawski; D. Roesti; F. Gillet; M. Aragno; P. Rossi

2002-01-01

362

Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis  

E-print Network

Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis by electrostatic forces, despite the ultralow dielectric constant of 1.5. Zeta potentials of micrometer- sized a dozen droplets with lengths of 50 m. The ability to form electrostatically stabilized colloids in carbon

363

SEPARATION OF GLUTEN PROTEINS BY HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

High performance capillary electrophoresis (HPCE) is an analytical method that uses a voltage differential to accurately move solvents and solutes through a capillary. HPCE is a relative newcomer to the field of cereal chemistry, it utilizes small inner diameter capillaries as an anti-convective med...

364

CAPILLARY ELECTROPHORESIS IMMUNOASSAY FOR 2,4-DICHLOROPHENOXYACETIC ACID  

EPA Science Inventory

A capillary electrophoresis (CE) immunoassay format for 2,4-dichlorophenoxyacetic acid (2,4-D) is demonstrated. A fluorescent labeled 2,4-D analog competes with the analyte of interest for a finite number of binding sites provided by anti-2,4-D monoclonal antibodies. CE then pr...

365

Enantioselective determination by capillary electrophoresis with cyclodextrins as chiral selectors  

Microsoft Academic Search

This review surveys the separation of enantiomers by capillary electrophoresis using cyclodextrins as chiral selector. Cyclodextrins or their derivatives have been widely employed for the direct chiral resolution of a wide number of enantiomers, mainly of pharmaceutical interest, selected examples are reported in the tables. For method optimisation, several parameters influencing the enantioresolution, e.g., cyclodextrin type and concentration, buffer pH

Salvatore Fanali

2000-01-01

366

Capillary electrophoresis of highly sulfated flavanoids and flavonoids Mandakini Dantuluria  

E-print Network

, was resolved into its enantiomers using 15% b-cyclodextrin, a chiral selector, but not with a- or c-cyclodextrins in the presence of cyclodextrins or chiral pos- itively charged amino acids. Overall, capillary electrophoresis sulfate; 6,20 ,30 -FS, 6,20 ,30 -flavonoid sulfate; Hdi, heparin disaccharide; a-CD, a-cyclodextrin; b

Desai, Umesh R

367

A Contactless Capacitance Detection System for Microchip Capillary Electrophoresis  

Microsoft Academic Search

The design, construction and operation of a simple, inexpensive and compact high voltage power supply for use in conjunction with a simple cross, capillary electrophoresis microchip is presented. The detection system utilizes a single high voltage power supply (15 kV), a voltage divider network for obtaining the required voltages for enabling a gated injection valve, and two high voltage relays

Peter Wu

2008-01-01

368

Separation of rat pituitary secretory granules by continuous flow electrophoresis  

NASA Technical Reports Server (NTRS)

The separation of growth hormone-containing cytoplasmic secretory granules from the rat pituitary gland by continuous flow electrophoresis is described. The results are consistent with the hypothesis that granule subpopulations can be separated due to differences in surface charge; these, in turn, may be related to the oligomeric state of the hormone.

Hayes, Daniel; Exton, Carrie; Salada, Thomas; Shellenberger, Kathy; Waddle, Jenny; Hymer, W. C.

1990-01-01

369

Measuring Genetic Variability in Natural Populations by Allozyme Electrophoresis  

NSDL National Science Digital Library

This resource provides a detailed introduction to the technique of gel electrophoresis as a means of analysing intra- and inter-population genetic variability. This exercise may be suited for incorporation with other laboratory or field experiments to provide additional information or a more synthetic framework.

James M. Bader (Case Western Reserve University; )

1998-01-01

370

An Inexpensive Device for Capillary Electrophoresis with Fluorescence Detection  

ERIC Educational Resources Information Center

We describe an inexpensive device for performing capillary electrophoresis (CE) separations with fluorescence detection. As a demonstration of the device's utility we have determined the mass of riboflavin in a commercially available dietary supplement. The device allows for separation of riboflavin in [asymptotically equivalent to] 100 s with a…

Anderson, Greg; Thompson, Jonathan E.; Shurrush, Khriesto

2006-01-01

371

Device for Horizontal Zone Electrophoresis in Free Electrolyte  

E-print Network

With expansion of area of application of an electromigration method the necessity of modernization of installation for horizontal zone electrophoresis in free electrolyte has appeared. A number of the basic modules was essentially advanced, that has allowed considerably increase reliability and accuracy of received results. The device is completely automated.

Priemyshev, A N; Bozhikov, G A; Alikov, B A; Salamatin, A V; Furyaev, T A; Maslov, O D; Milanov, M V; Dmitriev, S N

2000-01-01

372

Negative Pressure Wound Therapy of Chronically Infected Wounds Using 1% Acetic Acid Irrigation  

PubMed Central

Background Negative-pressure wound therapy (NPWT) induces angiogenesis and collagen synthesis to promote tissue healing. Although acetic acid soaks normalize alkali wound conditions to raise tissue oxygen saturation and deconstruct the biofilms of chronic wounds, frequent dressing changes are required. Methods Combined use of NPWT and acetic acid irrigation was assessed in the treatment of chronic wounds, instilling acetic acid solution (1%) beneath polyurethane membranes twice daily for three weeks under continuous pressure (125 mm Hg). Clinical photographs, pH levels, cultures, and debrided fragments of wounds were obtained pre- and posttreatment. Tissue immunostaining (CD31, Ki-67, and CD45) and reverse transcription-polymerase chain reaction (vascular endothelial growth factor [VEGF], vascular endothelial growth factor receptor [VEGFR]; procollagen; hypoxia-inducible factor 1 alpha [HIF-1-alpha]; matrix metalloproteinase [MMP]-1,-3,-9; and tissue inhibitor of metalloproteinase [TIMP]) were also performed. Results Wound sizes tended to diminish with the combined therapy, accompanied by drops in wound pH (weakly acidic or neutral) and less evidence of infection. CD31 and Ki-67 immunostaining increased (P<0.05) post-treatment, as did the levels of VEGFR, procollagen, and MMP-1 (P<0.05), whereas the VEGF, HIF-1-alpha, and MMP-9/TIMP levels declined (P<0.05). Conclusions By combining acetic acid irrigation with negative-pressure dressings, both the pH and the size of chronic wounds can be reduced and infections be controlled. This approach may enhance angiogenesis and collagen synthesis in wounds, restoring the extracellular matrix. PMID:25606491

Lee, Byeong Ho; Lee, Hye Kyung; Kim, Hyoung Suk; Moon, Min Seon; Suh, In Suck

2015-01-01

373

Analysis of Bacterial Communities in Seagrass Bed Sediments by Double-Gradient Denaturing Gradient Gel Electrophoresis  

E-print Network

-Gradient Denaturing Gradient Gel Electrophoresis of PCR-Amplified 16S rRNA Genes J.B. James1 , T.D. Sherman2 and R denaturing gradient gel electrophoresis (DG- DGGE) was used to generate banding patterns from

Sherman, Tim

374

Oxidation of Indole-3-Acetic Acid to Oxindole-3-Acetic Acid by an Enzyme Preparation from Zea mays1  

PubMed Central

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants. PMID:11538238

Reinecke, Dennis M.; Bandurski, Robert S.

1988-01-01

375

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays  

NASA Technical Reports Server (NTRS)

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Reinecke, D. M.; Bandurski, R. S.

1988-01-01

376

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, D.; Waller, F.J.

1999-04-06

377

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

1999-01-01

378

Membrane magic  

SciTech Connect

The Kansas Power and Light Co.'s La Cyne generating station has found success with membrane filtration water pretreatment technology. The article recounts the process followed in late 2004 to install a Pall Aria 4 microfilter in Unit 1 makeup water system at the plant to produce cleaner water for reverse osmosis feed. 2 figs., 2 photos.

Buecker, B. [Kansas City Power and Light Co. (United States)

2005-09-01

379

Fatbag Membrane  

USGS Multimedia Gallery

Although oil and water do not normally mix, oil contaminants in waterways can be measured using a special membrane nicknamed a "fatbag." The fatbags absorb many fat-soluble chemicals from the water at a known rate, so they can be used to estimate the concentration of such chemicals....

2010-07-20

380

STUDIES OF MEMBRANE FORMATION IN TETRAHYMENA PYRIFORMIS  

PubMed Central

When 1-14C-palmitic acid is used to pulse label logarithmic cultures of Tetrahymena pyriformis, radioactivity appears in lipids of the various membrane types at vastly differing rates. The microsomes and postmicrosomal supernatant attain a high specific radioactivity within 1 min, while the membranes enveloping the cilia require several hours to reach the microsomal level. A similar pattern is obtained when the tracer is sodium 1-14C-acetate or 8,9-3H-hexadecyl glycerol. In all fractions the phosphonolipid incorporates radioactivity from 14C-palmitate much less rapidly than do the other major phospholipids. The patterns of labeling suggest that new lipids are transported from a cytoplasmic site of synthesis to points of membrane fabrication throughout the cell. PMID:5092209

Nozawa, Yoshinori; Thompson, Guy A.

1971-01-01

381

Electric and hydrodynamic stretching of DNA-polymer conjugates in free-solution electrophoresis  

E-print Network

Electric and hydrodynamic stretching of DNA-polymer conjugates in free-solution electrophoresis S The conjugation of an uncharged polymer to DNA fragments makes it possible to separate DNA by free-solution electrophoresis. This end-labeled free-solution electrophoresis method has been shown to successfully separate ss

Barron, Annelise E.

382

Antitumor and apoptotic activities of the chemical constituents from the ethyl acetate extract of Artemisia indica.  

PubMed

Cancer is one of the most eminent diseases of modern times and numerous natural products derived from medicinal plants have been identified as potential sources of antitumor drugs. A successful anticancer drug must target or inhibit tumor cells whilst causing minimal damage to healthy cells. The present study aimed to investigate the antitumor efficacy of ethyl acetate extract, and other isolated compounds from Artemisia indica, on MCF?7, BHY, Miapaca?2, Colo?205 and A?549 cell lines. The apoptotic activity of the compounds was studied using flow cytometry. The different cancer cell lines were treated with the ethyl acetate extract and varying concentrations of compounds (denoted a?g) isolated from the A. indica. The cytotoxicity was evaluated by MTT assay and the apoptotic properties of the compounds and the extract were assessed using flow cytometry. In MCF?7 cells, the effect on mitochondrial membrane potential loss (??m) induced by compounds b and d was also studied. Bioassay?guided fractionation of the ethyl acetate extract from the shoot and root parts of A. indica led to the identification of the compounds a?g as: 5?hydroxy?3,7,4'?trimethoxyflavone; ludartin; maackiain; lupeol; cis?matricaria ester; trans?matricaria ester; and 6?methoxy?7,8?methylenedioxy coumarin, respectively. All the compounds exhibited mild to potent inhibition of cell proliferation in all the cell lines, with the half maximal inhibitory concentration values ranging from 25.18?88.12 µM. Ludartin and lupeol were observed to have the most potent inhibitory effects. Based on the initially identified antiproliferative effects, these two compounds were evaluated for their effects on cell cycle phase distribution, DNA damage and their effects on mitochondrial membrane potential loss (??m). The two compounds induced DNA damage and mitochondrial membrane potential loss in MCF?7 cells. The results of the current study suggest that lupeol and ludartin, isolated from A. indica, produce anticancer effects by inducing DNA damage and a reduction of mitochondrial membrane potential, and may be used as potent anticancer agents, subsequent to further study. PMID:25434991

Zeng, Ying-Tong; Jiang, Jian-Min; Lao, Hai-Yan; Guo, Jie-Wen; Lun, Yu-Ning; Yang, Min

2015-03-01

383

Integral and peripheral association of proteins and protein complexes with Yersinia pestis inner and outer membranes  

Microsoft Academic Search

Yersinia pestis proteins were sequentially extracted from crude membranes with a high salt buffer (2.5 M NaBr), an alkaline solution (180 mM Na2CO3, pH 11.3) and membrane denaturants (8 M urea, 2 M thiourea and 1% amidosulfobetaine-14). Separation of proteins by 2D gel electrophoresis was followed by identification of more than 600 gene products by MS. Data from differential 2D

Rembert Pieper; Shih-Ting Huang; David J. Clark; Jeffrey M. Robinson; Hamid Alami; Prashanth P. Parmar; Moo-Jin Suh; Srilatha Kuntumalla; Christine L. Bunai; Robert D. Perry; Robert D. Fleischmann; Scott N. Peterson

2009-01-01

384

Challenges and solutions for the identification of membrane proteins in non-model plants  

Microsoft Academic Search

The workhorse for proteomics in non-model plants is classical two-dimensional electrophoresis, a combination of iso-electric focusing and SDS-PAGE. However, membrane proteins with multiple membrane spanning domains are hardly detected on classical 2-DE gels because of their low abundance and poor solubility in aqueous media. In the current review, solutions that have been proposed to handle these two problems in non-model

A. Vertommen; B. Panis; R. Swennen; S. C. Carpentier

2011-01-01

385

Federated two-dimensional electrophoresis database: a simple means of publishing two-dimensional electrophoresis data.  

PubMed

While a two-dimensional electrophoresis (2-DE) database is a relatively old concept, in recent years it generated renewed interest within the 2-DE community due to two main factors: (i) The high reproducibility of the current 2-DE method allows 2-DE images to be exchanged and compared between laboratories. (ii) The recent development of faster and more powerful techniques for protein identification such as microsequencing, matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) and amino acid composition makes the production of reference protein maps and 2-DE databases cost- and time-effective. Additionally, the Internet network's current increase in popularity, combined with the rapid growth of Internet-connected laboratories, provides a straightforward means of publishing and sharing 2-DE data. While a small number of laboratories have already successfully published their data over the net, the increasing number of 2-DE database servers that are currently being set up will sooner or later require some kind of standardization. Unfortunately, standardization can be a long and cumbersome process inevitably leading to undesirable compromises. A federated database offers a simple and efficient way to publish and share 2-DE data without the need for standardization. Taking advantage of Internet protocols such as World Wide Web, they allow each laboratory to maintain their own database and to interconnect it with other similar databases through the use of active cross-references. This paper first presents guidelines for building a federated 2-DE database that may easily be followed by most laboratories. It then briefly reviews the state-of-the-art in networked 2-DE databases, and finally describes the SWISS-2DPAGE database which fully implements the concept of a federated 2-DE database. PMID:8740178

Appel, R D; Bairoch, A; Sanchez, J C; Vargas, J R; Golaz, O; Pasquali, C; Hochstrasser, D F

1996-03-01

386

Origin and fate of acetate in an acidic fen.  

PubMed

Acetate is a central intermediate in the anaerobic degradation of organic matter, and the resolution of its metabolism necessitates integrated strategies. This study aims to (1) estimate the contribution of acetogenesis to acetate formation in an acidic fen (pH ~ 4.9), (2) assess the genetic potential for acetogenesis targeting the fhs gene encoding formyltetrahydrofolate synthetase (FTHFS) and (3) unravel the in situ turnover of acetate using stable carbon isotope pore-water analysis. H(2)/CO(2)-supplemented peat microcosms yielded (13)C-depleted acetate (-37.2‰ vs. VPDB (Vienna Peedee belemnite standard) compared with -14.2‰ vs. VPDB in an unamended control), indicating the potential for H(2)-dependent acetogenesis. Molecular analysis revealed a high diversity and depth-dependent distribution of fhs phylotypes with the highest number of operational taxonomic units in 0-20 cm depth, but only few and distant relationships to known acetogens. In pore waters, acetate concentrations (0-170 ?M) and ?(13)C-values varied widely (-17.4‰ to -3.4‰ vs. VPDB) and did not indicate acetogenesis, but pointed to a predominance of sinks, which preferentially consumed (12)C-acetate, like acetoclastic methanogenesis. However, depth profiles of methane and ?(13)C(CH4) revealed a temporarily and spatially restricted role of this acetate sink and suggest other processes like sulfate and iron reduction played an important role in acetate turnover. PMID:22404042

Hädrich, Anke; Heuer, Verena B; Herrmann, Martina; Hinrichs, Kai-Uwe; Küsel, Kirsten

2012-08-01

387

Selective perborate signaling by deprotection of fluorescein and resorufin acetates.  

PubMed

The acetate derivatives of fluorescein and resorufin exhibited a prominent turn-on type signaling behavior toward BO(3)(-) ions over other common anions. Signaling is based on the selective deprotection of acetate groups by perborate, which resulted in significant chromogenic and fluorogenic signaling. Compound 1 also exhibited a pronounced perborate selectivity over other commonly used oxidants in 90% aqueous acetonitrile solution. PMID:20222739

Choi, Myung Gil; Cha, Sunyoung; Park, Ji Eun; Lee, Haekyung; Jeon, Hye Lim; Chang, Suk-Kyu

2010-04-01

388

Introduction Metal acetates are used as metal precursors in many  

E-print Network

facilitated exploring broader applications of metal and metal oxide nanoparticles by utilizing the synthesis properties of the solid phase metal acetate precursors and the product metal/metal oxide nanocomposite in these combustion and other synthesis systems which rely on thermal decomposition and oxidation of metal acetates [6

Wooldridge, Margaret S.

389

Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.  

ERIC Educational Resources Information Center

Presents a study of the rhodium-catalyzed, ioding-promoted carbonylation of methyl acetate. This study provides an interesting contrast between the carbonylation of methyl acetate and the carbonylation of methanol when similar rhodium/iodine catalyst systems are used. (JN)

Polichnowski, S. W.

1986-01-01

390

Enrichment of amino acid-oxidizing, acetate-reducing bacteria.  

PubMed

In anaerobic condition, amino acids are oxidatively deaminated, and decarboxylated, resulting in the production of volatile fatty acids. In this process, excess electrons are produced and their consumption is necessary for the accomplishment of amino acid degradation. In this study, we anaerobically constructed leucine-degrading enrichment cultures from three different environmental samples (compost, excess sludge, and rice field soil) in order to investigate the diversity of electron-consuming reaction coupled to amino acid oxidation. Constructed enrichment cultures oxidized leucine to isovalerate and their activities were strongly dependent on acetate. Analysis of volatile fatty acids (VFAs) profiles and community structure analysis during batch culture of each enrichment indicated that Clostridium cluster I coupled leucine oxidation to acetate reduction in the enrichment from the compost and the rice field soil. In these cases, acetate was reduced to butyrate. On the other hand, Clostridium cluster XIVb coupled leucine oxidation to acetate reduction in the enrichment from the excess sludge. In this case, acetate was reduced to propionate. To our surprise, the enrichment from rice field soil oxidized leucine even in the absence of acetate and produced butyrate. The enrichment would couple leucine oxidation to reductive butyrate synthesis from CO2. The coupling reaction would be achieved based on trophic link between hydrogenotrophic acetogenic bacteria and acetate-reducing bacteria by sequential reduction of CO2 and acetate. Our study suggests anaerobic degradation of amino acids is achieved yet-to-be described reactions. PMID:24630616

Ato, Makoto; Ishii, Masaharu; Igarashi, Yasuo

2014-08-01

391

Acetic acid pulping of wheat straw under atmospheric pressure  

Microsoft Academic Search

Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw was made of the chemical com- position, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and fractionated into pulp

Xue-Jun PanYoshihiro Sano

1999-01-01

392

Water vapor diffusion membrane development  

NASA Technical Reports Server (NTRS)

An application of the water vapor diffusion technique is examined whereby the permeated water vapor is vented to space vacuum to alleviate on-board waste storage and provide supplemental cooling. The work reported herein deals primarily with the vapor diffusion-heat rejection (VD-HR) as it applies to the Space Shuttle. A stack configuration was selected, designed and fabricated. An asymmetric cellulose acetate membrane, used in reverse osmosis application was selected and a special spacer was designed to enhance mixing and promote mass transfer. A skid-mount unit was assembled from components used in the bench unit although no attempt was made to render it flight-suitable. The operating conditions of the VD-HR were examined and defined and a 60-day continuous test was carried out. The membranes performed very well throughout the test; no membrane rupture and no unusual flux decay was observed. In addition, a tentative design for a flight-suitable VD-HR unit was made.

Tan, M. K.

1977-01-01

393

Glycerol acetals as anti-freezing additives for biodiesel.  

PubMed

Glycerol acetals from butanal, pentanal, hexanal, octanal and decanal were prepared with the use of Amberlyst-15 acid resin as catalyst. The glycerol conversion decreases with the size of the hydrocarbon chain. This fact has been associated with formation of micelles and aggregates of the aldehyde to minimize the interaction between the polar glycerol molecule with the hydrocarbon chain. The Z+E mixture of the acetals with five and six-member rings were produced in all cases. The distribution of the acetal isomers varied with the reaction time, especially for the long chain aldehydes. Addition of 5 vol.% of the butanal-glycerol acetal reduced the pour point of animal fat biodiesel (methyl ester) from 18 to 13 degrees C. The decrease in the pour point of the glycerol acetals-biodiesel mixtures were dependent on the size of the hydrocarbon chain and the percent blended. PMID:20304633

Silva, Paulo H R; Gonçalves, Valter L C; Mota, Claudio J A

2010-08-01

394

Membranes and sorting Membrane permeability  

E-print Network

, schemes and pictures) on the Golgi complex, lysosomes, peroxisomes, chaperone proteins, signal recognition of intracellular membranes (URL http://www2uchc. edu/-teraeaki/seawater.html). `Heme and Iron' http:llwww.hahnemann.edu/heme-iron, with comprehen- sive graphics, about the metabolism, adsorption and regulation of uptake of iron. `Protein

Kirchhausen, Tomas

395

Mechanical Properties and a Physical-Chemical Analysis of Acetate Yarns  

Microsoft Academic Search

Cellulose acetate used in the manufacture of acetate yarns is commonly obtained from cotton-linters or wood-pulp cellulose. Varying in the origin and in the manufacturer, cellulose acetate often differs in its processability. The paper belongs to the investigation the properties of acetate yarns manufactured of the cellulose acetate varied in its origin and manufactured by different suppliers. Mechanical properties (including

R. emaitaitien?; A. Vitkauskas

396

Development of a hollow fibre liquid-phase micro extraction method coupled with capillary electrophoresis/mass spectrometry for determining nitrophenolic compounds from atmospheric particles  

NASA Astrophysics Data System (ADS)

Nitrophenolic compounds present in the atmosphere gained a lot of attention as they are known for their negative effect on human health as well as for their phytotoxity being a cause for forest decline. Moreover, nitrophenols have the ability to absorb light in the range of near ultra violet to visible light, thus they are also contributing to the so-called brown carbon. Most of the available methods for determining nitrophenols in particulate matter are using organic solvents for extraction. Those methods are not applicable if one wants to focus only on the water-soluble fraction. Therefore, a method using a three-phase hollow fibre liquid-phase micro extraction (HF-LPME) was developed to enrich nine nitrophenolic compounds (2-Nitrophenol, 3-Nitrophenol, 4-Nitrophenol, 2-Methyl-4-nitrophenol, 3-Methyl-4-nitrophenol, 4-Nitrocatechol, 2,6-Dimethyl-4-nitrophenol, 2,4-Dinitrophenol, 3,4-Dinitrophenol) from aqueous extracts of atmospheric particles. Analysis was performed by capillary electrophoresis coupled with electrospray ionisation mass spectrometry (CE-ESI-MS). The background electrolyte composition was optimised to a 20 mM ammonium acetate buffer at pH 9.7 containing 15% methanol (v/v). Persistent peak tailing during electrophoretic separation was observed for 4-Nitrocatechol. Flushing the capillary with Ethylenediaminetetraacetic acid (EDTA) prior sample injection strongly improved the peak shape. Four extraction parameters (composition of organic liquid membrane, pH of acceptor phase, salting out effect, extraction time) and their effect on the analyte recoveries were examined. The HF-LPME consisted of 1.8 mL sample solution kept at pH 2 as donor phase and 15 µl 100 mM aqueous ammonia solution as acceptor phase inserted into a hollow fibre. Dihexyl ether was used to form a supported liquid membrane inside the pores of the hollow fibre. As a result low detection limits in the range of nmol L-1 were achieved and the developed method was found to be competitive with more established methods. Recoveries between 11 and 90% of aqueous standard solutions could be obtained with enrichment factors between 10 and 100. Interday and intraday repeatability were tested and found to be in an acceptable range for most compounds (6-15% and 7-10%, respectively). However, they were higher for 4-Nitrocatechol (59% and 48%) and 2-Nitrophenol (17% and 35%). The developed method was successfully applied to exemplary samples of atmospheric particulate matter from field experiments. Five out of nine investigated nitrophenols could be determined in atmospheric particles collected at the rural research station Melpitz (Saxony, Germany). The obtained results indicate that out of the investigated compounds 4-Nitrophenol is present at the highest concentrations followed by 4-Nitrocatechol. Furthermore, it was found that nitrophenols are present in higher concentrations in winter than in summer samples indicating that sources are more likely available in winter time.

Teich, Monique; van Pinxteren, Dominik; Herrmann, Hartmut

2014-05-01

397

Mitochondrial degradation in acetic acid-induced yeast apoptosis: the role of Pep4 and the ADP/ATP carrier.  

PubMed

We have previously shown that acetic acid activates a mitochondria-dependent death process in Saccharomyces cerevisiae and that the ADP/ATP carrier (AAC) is required for mitochondrial outer membrane permeabilization and cytochrome c release. Mitochondrial fragmentation and degradation have also been shown in response to this death stimulus. Herein, we show that autophagy is not active in cells undergoing acetic acid-induced apoptosis and is therefore not responsible for mitochondrial degradation. Furthermore, we found that the vacuolar protease Pep4p and the AAC proteins have a role in mitochondrial degradation using yeast genetic approaches. Depletion and overexpression of Pep4p, an orthologue of human cathepsin D, delays and enhances mitochondrial degradation respectively. Moreover, Pep4p is released from the vacuole into the cytosol in response to acetic acid treatment. AAC-deleted cells also show a decrease in mitochondrial degradation in response to acetic acid and are not defective in Pep4p release. Therefore, AAC proteins seem to affect mitochondrial degradation at a step subsequent to Pep4p release, possibly triggering degradation through their involvement in mitochondrial permeabilization. The finding that both mitochondrial AAC proteins and the vacuolar Pep4p interfere with mitochondrial degradation suggests a complex regulation and interplay between mitochondria and the vacuole in yeast programmed cell death. PMID:20345665

Pereira, Clara; Chaves, Susana; Alves, Sara; Salin, Bénédict; Camougrand, Nadine; Manon, Stéphen; Sousa, Maria João; Côrte-Real, Manuela

2010-06-01

398

Selective deprotection of acetals with Me3SiCH2MgCl. Peterson-type olefination of acetals  

PubMed

By employing the chelation strategy, treatment of an acetal of a contiguous diol with Me3SiCH2MgCl liberates the corresponding diol regioselectively. In addition, acetals of different structural variety are transformed upon treatment with Me3SiCH2MgCl and ZnI2 into the corresponding olefination products in good yield. PMID:10959876

Chiang; Chen; Hsieh; Luh

2000-07-28

399

Oxidation of Indole-3-acetic Acid and Oxindole-3-acetic Acid to 2,3-Dihydro-7-hydroxy-2-oxo-1H Indole-3-acetic Acid-7?-O-?-d-Glucopyranoside in Zea mays Seedlings 1  

PubMed Central

Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7?-O-?-d-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid ? Oxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid-glucoside. PMID:11540902

Nonhebel, Heather M.; Bandurski, Robert S.

1984-01-01

400

Improving the Expression of Recombinant Proteins in E. coli BL21 (DE3) under Acetate Stress: An Alkaline pH Shift Approach  

PubMed Central

Excess acetate has long been an issue for the production of recombinant proteins in E. coli cells. Recently, improvements in acetate tolerance have been achieved through the use of genetic strategies and medium supplementation with certain amino acids and pyrimidines. The aim of our study was to evaluate an alternative to improve the acetate tolerance of E. coli BL21 (DE3), a popular strain used to express recombinant proteins. In this work we reported the cultivation of BL21 (DE3) in complex media containing acetate at high concentrations. In the presence of 300 mM acetate, compared with pH 6.5, pH 7.5 improved cell growth by approximately 71%, reduced intracellular acetate by approximately 50%, and restored the expression of glutathione S-transferase (GST), green fluorescent protein (GFP) and cytochrome P450 monooxygenase (CYP). Further experiments showed that alkaline pHs up to 8.5 had little inhibition in the expression of GST, GFP and CYP. In addition, the detrimental effect of acetate on the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) by the cell membrane, an index of cellular metabolic capacity, was substantially alleviated by a shift to alkaline pH values of 7.5–8.0. Thus, we suggest an approach of cultivating E. coli BL21 (DE3) at pH 8.0±0.5 to minimize the effects caused by acetate stress. The proposed strategy of an alkaline pH shift is a simple approach to solving similar bioprocessing problems in the production of biofuels and biochemicals from sugars. PMID:25402470

Wang, Hengwei; Wang, Fengqing; Wang, Wei; Yao, Xueling; Wei, Dongzhi; Cheng, Hairong; Deng, Zixin

2014-01-01

401

Imaging Catalytic Surfaces by Multiplexed Capillary Electrophoresis With Absorption Detection  

SciTech Connect

A new technique for in situ imaging and screening heterogeneous catalysts by using multiplexed capillary electrophoresis with absorption detection was developed. By bundling the inlets of a large number of capillaries, an imaging probe can be created that can be used to sample products formed directly from a catalytic surface with high spatial resolution. In this work, they used surfaces made of platinum, iron or gold wires as model catalytic surfaces for imaging. Various shapes were recorded including squares and triangles. Model catalytic surfaces consisting of both iron and platinum wires in the shape of a cross were also imaged successfully. Each of the two wires produced a different electrochemical product that was separated by capillary electrophoresis. Based on the collected data they were able to distinguish the products from each wire in the reconstructed image.

Michael Christodoulou

2002-08-27

402

Electrophoresis of a DNA Coil Near a Nanopore  

E-print Network

Motivated by DNA electrophoresis near a nanopore, we consider the flow field around an "elongated jet", a long thin source which injects momentum into a liquid. This solution qualitatively describes the electro-osmotic flow around a long rigid polymer, where due to electrohydrodynamic coupling, the solvent receives momentum from the electric field. Based on the qualitative behavior of the elongated jet solution, we develop a coarse-grained scheme which reproduces the known theoretical results regarding the electrophoretic behavior of a long rigid polymer and a polymer coil in a uniform field, which we then exploit to analyze the electrophoresis of a polymer coil in the non-uniform field near a nanopore.

Rowghanian, Payam

2013-01-01

403

Analytical separations of lanthanides and actinides by capillary electrophoresis.  

PubMed

The separation of lanthanide and actinide elements belongs to one of the most challenging tasks of the separation science, due to a great similarity in their physical and chemical properties. The electrophoretic separation can be accomplished in the presence of suitable complex-forming agents, from which alpha-hydroxyisobutyric acid (HIBA) has been used most often. In the most effective capillary electrophoretic mode--capillary zone electrophoresis (CZE)--a complete separation of lanthanide ions can be accomplished within a few minutes. Various electrophoretic methods can be relatively easily adopted for the determinations of individual lanthanide elements in certain kinds of technical materials, concentrates, precursors, etc., where the high speed and low costs of analysis characteristics of capillary electrophoresis (CE) may be advantageously exploited. Electrophoretic techniques may also be employed for speciation studies, especially for examinations of the behavior of actinides in the environment. PMID:12858369

Janos, Pavel

2003-06-01

404

SDS capillary gel electrophoresis of proteins in microfabricated channels  

PubMed Central

Analysis of variations in the concentrations or structures of biomolecules (e.g., mRNAs, proteins, peptides, natural products) that occur either naturally or in response to environmental or genetic perturbations can provide important insight into complex biological processes. Many biological samples are mixtures that require a separation step before quantitation of variations in the individual components. Two-dimensional denaturing gel electrophoresis has been used very effectively to separate complex mixtures of proteins, but it is time consuming and requires considerable amounts of sample. Microchannel-based separations have proven very effective in rapidly separating small amounts of nucleic acids; more recently, isoelectric focusing of proteins also has been adapted to the microchannel format. Here, we describe microchannel-based SDS capillary gel electrophoresis of proteins and demonstrate the speed and high resolution it provides. This development is an important step toward the miniaturization and integration of multidimensional and array separation methods for complex protein mixtures. PMID:10318890

Yao, Shao; Anex, Deon S.; Caldwell, W. Brett; Arnold, Don W.; Smith, Katherine B.; Schultz, Peter G.

1999-01-01

405

Applications of space-electrophoresis in medicine. [for cellular separations in molecular biology  

NASA Technical Reports Server (NTRS)

The nature of electrophoresis is reviewed and potential advances realizable in the field of biology and medicine from a space electrophoresis facility are examined. The ground-based applications of electrophoresis: (1) characterization of an ionized species; (2) determination of the quantitative composition of a complex mixture; and (3) isolation of the components of a mixture, separation achieved on the basis of the difference in transport rates is reviewed. The electrophoresis of living cells is considered, touching upon the following areas: the separation of T and B lymphocytes; the genetic influence on mouse lymphocyte mobilities; the abnormal production of specific and monoclonal immunoproteins; and the study of cancer. Schematic diagrams are presented of three types of electrophoresis apparatus: the column assembly for the static electrophoresis experiment on the Apollo-Soyuz mission, the continuous flow apparatus used in the same mission and a miniaturized electrophoresis apparatus.

Bier, M.

1976-01-01

406

The electrophoresis of transferrins in urea/polyacrylamide gels.  

PubMed Central

The denaturation of transferrin by urea has been studied by (a) electrophoresis in polyacrylamide gels incorporating a urea gradient, (b) measurements of the loss of iron-binding capacity and (c) u.v. difference spectrometry. In human serum transferrin and hen ovotransferrin the N-terminal and C-terminal domains of the iron-free protein were found to denature at different urea concentrations. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 7. PMID:7213345

Evans, R W; Williams, J

1980-01-01

407

Sheathless interface for coupling capillary electrophoresis with mass spectrometry  

SciTech Connect

A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

Wang, Chenchen; Tang, Keqi; Smith, Richard D.

2014-06-17

408

Recent advances of capillary electrophoresis in pharmaceutical analysis  

Microsoft Academic Search

This review covers recent advances of capillary electrophoresis (CE) in pharmaceutical analysis. The principle, instrumentation,\\u000a and conventional modes of CE are briefly discussed. Advances in the different CE techniques (non-aqueous CE, microemulsion\\u000a electrokinetic chromatography, capillary isotachophoresis, capillary electrochromatography, and immunoaffinity CE), detection\\u000a techniques (mass spectrometry, light-emitting diode, fluorescence, chemiluminescence, and contactless conductivity), on-line\\u000a sample pretreatment (flow injection) and chiral separation

Leena Suntornsuk

2010-01-01

409

Ultra-high-speed DNA sequencing using capillary electrophoresis chips  

Microsoft Academic Search

DNA sequencing has been performed on microfabricated capillary electrophoresis chips. DNA separations were achieved in 50 x 8 μm cross-section channels microfabricated in a 2 in. x 3 in. glass sandwich structure using a denaturing 9% T, 0% C polyacrylamide sieving medium. DNA sequencing fragment ladders were produced and fluorescently labeled using the recently developed energy transfer dye-labeled primers. Sequencing

Adam T. Woolley; Richard A. Mathies

1995-01-01

410

Computerized image analysis for acetic acid induced intraepithelial lesions  

NASA Astrophysics Data System (ADS)

Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

2008-03-01

411

The Effects of Acetate Buffer Concentration on Lysozyme Solubility  

NASA Technical Reports Server (NTRS)

The micro-solubility column technique was employed to systematically investigate the effects of buffer concentration on tetragonal lysozyme solubility. While keeping the NaCl concentrations constant at 2%, 3%, 4%, 5% and 7%, and the pH at 4.0, we have studied the solubility of tetragonal lysozyme over an acetate buffer concentration range of 0.01M to 0.5M as a function of temperature. The lysozyme solubility decreased with increasing acetate concentration from 0.01M to 0.1M. This decrease may simply be due to the net increase in solvent ionic strength. Increasing the acetate concentration beyond 0.1M resulted in an increase in the lysozyme solubility, which reached a peak at - 0.3M acetate concentration. This increase was believed to be due to the increased binding of acetate to the anionic binding sites of lysozyme, preventing their occupation by chloride. In keeping with the previously observed reversal of the Hoffmeister series for effectiveness of anions in crystallizing lysozyme, acetate would be a less effective precipitant than chloride. Further increasing the acetate concentration beyond 0.3M resulted in a subsequent gradual decrease in the lysozyme solubility at all NaCl concentrations.

Forsythe, Elizabeth L.; Pusey, Marc L.

1996-01-01

412

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

PubMed

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 of both methods showed that restriction fragment PFGE of SpeI digests of total DNA was a suitable method for strain typing and for determining which strains were present in vinegar fermentations. Results showed that strains of the species Gluconacetobacter europaeus were the most frequent leader strains of fermentations by the submerged method in the studied vinegars, and among them strain R1 was the predominant one. Results showed as well that mixed populations (at least two different strains) occurred in vinegars from cider and wine, whereas unique strains were found in spirit vinegars, which offered the most stressing conditions for bacterial growth. PMID:20832673

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

2010-12-01

413

Visualization of DNA molecules in time during electrophoresis  

NASA Technical Reports Server (NTRS)

For several years individual DNA molecules have been observed and photographed during agarose gel electrophoresis. The DNA molecule is clearly the largest molecule known. Nevertheless, the largest molecule is still too small to be seen using a microscope. A technique developed by Morikawa and Yanagida has made it possible to visualize individual DNA molecules. When these long molecules are labeled with appropriate fluorescence dyes and observed under a fluorescence microscope, although it is not possible to directly visualize the local ultrastructure of the molecules, yet because they are long light emitting chains, their microscopic dynamical behavior can be observed. This visualization works in the same principle that enables one to observe a star through a telescope because it emits light against a dark background. The dynamics of individual DNA molecules migrating through agarose matrix during electrophoresis have been described by Smith et al. (1989), Schwartz and Koval (1989), and Bustamante et al. (1990). DNA molecules during agarose gel electrophoresis advance lengthwise thorough the gel in an extended configuration. They display an extension-contraction motion and tend to bunch up in their leading ends as the 'heads' find new pores through the gel. From time to time they get hooked on obstacles in the gel to form U-shaped configurations before they resume their linear configuration.

Lubega, Seth

1991-01-01

414

Capillary zone electrophoresis-mass spectrometry of peptides and proteins  

SciTech Connect

Capillary zone electrophoresis (CZE) is attracting extensive attention as a fast, high resolution analytical and micro-preparative separations technique for systems of biological interest. In zone electrophoresis, a column is filled with a single electrolyte having a specific conductivity. The mixture of substances to be separated is applied as a narrow band to the head of a buffer filled column in a band whose width is much less than the length of the column and at a concentration too low to affect the buffer conductivity. An electric field is then applied across the length of the column and the individual substances migrate and separate according to their net electrophoretic velocities. Zone electrophoresis carried out in small diameter (<100 ..mu..m) fused silica capillaries is a relatively new approach to the high resolution separation of aqueous samples. Very small volume samples (picoliter range) with separation efficiencies on the order of 10/sup 6/ theoretical plates for amino acids have been achieved. The method can be further enhanced by the dynamic combination of detection sensitivity and selectivity offered by mass spectrometry (MS). The on-line marriage of mass spectrometry to CZE is accomplished by an atmospheric pressure electrospray ionization source interface. Our research efforts have demonstrated that proteins with MW's greater than 100 kDa can be analyzed using a conventional quadrupole mass spectrometer with an upper m/z limit of only 1700. 6 refs.

Loo, J.A.; Udseth, H.R.; Smith, R.D.

1989-05-01

415

Procedures for two-dimensional electrophoresis of proteins  

SciTech Connect

High-resolution two-dimensional gel electrophoresis (2DE) of proteins, using isoelectric focusing in the first dimension and sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) in the second, was first described in 1975. In the 20 years since those publications, numerous modifications of the original method have evolved. The ISO-DALT system of 2DE is a high-throughput approach that has stood the test of time. The problem of casting many isoelectric focusing gels and SDS-PAGE slab gels (up to 20) in a reproducible manner has been solved by the use of the techniques and equipment described in this manual. The ISO-DALT system of two-dimensional gel electrophoresis originated in the late 1970s and has been modified many times to improve its high-resolution, high-throughput capabilities. This report provides the detailed procedures used with the current ISO-DALT system to prepare, run, stain, and photograph two-dimensional gels for protein analysis.

Tollaksen, S.L.; Giometti, C.S.

1996-10-01

416

Microfabricated capillary electrophoresis amino acid chirality analyzer for extraterrestrial exploration  

NASA Technical Reports Server (NTRS)

Chiral separations of fluorescein isothiocyanate-labeled amino acids have been performed on a microfabricated capillary electrophoresis chip to explore the feasibility of using such devices to analyze for extinct or extant life signs in extraterrestrial environments. The test system consists of a folded electrophoresis channel (19.0 cm long x 150 microns wide x 20 microns deep) that was photolithographically fabricated in a 10-cm-diameter glass wafer sandwich, coupled to a laser-excited confocal fluorescence detection apparatus providing subattomole sensitivity. Using a sodium dodecyl sulfate/gamma-cyclodextrin pH 10.0 carbonate electrophoresis buffer and a separation voltage of 550 V/cm at 10 degrees C, baseline resolution was observed for Val, Ala, Glu, and Asp enantiomers and Gly in only 4 min. Enantiomeric ratios were determined for amino acids extracted from the Murchison meteorite, and these values closely matched values determined by HPLC. These results demonstrate the feasibility of using microfabricated lab-on-a-chip systems to analyze extraterrestrial samples for amino acids.

Hutt, L. D.; Glavin, D. P.; Bada, J. L.; Mathies, R. A.

1999-01-01

417

Characterization of Listeria monocytogenes isolates by esterase electrophoresis.  

PubMed Central

Multiple bands of alpha-naphthyl-propionyl esterase (alpha NPE) activity observed following starch gel electrophoresis of cell extracts allowed 219 Listeria monocytogenes isolates from milk, nondairy foods, and clinical and veterinary sources to be assigned to 17 different alpha NPE types. Multilocus enzyme electrophoresis (MEE) analysis was used to obtain electrophoretic mobility data for alpha NPEs and nine other metabolic enzymes; on the basis of these data, the 219 strains were assigned to 59 electrophoretic types. Each of the methods separated the strains into two main groups, and there was extensive agreement on assignment of the strains to the groups. Although the method is less discriminatory than MEE, the usefulness of alpha NPE electrophoresis alone as a rapid, simple typing method for L. monocytogenes for certain purposes is indicated by agreement among alpha NPE, MEE, and restriction fragment length polymorphism types as molecular markers for persistent and transient L. monocytogenes strains found in sequential raw-milk and nondairy food samples obtained from different processors. PMID:8919813

Harvey, J; Gilmour, A

1996-01-01

418

Automated Lab-on-a-Chip Electrophoresis System  

NASA Technical Reports Server (NTRS)

Capillary electrophoresis is an analytical technique that can be used to detect and quantify extremely small amounts of various biological molecules. In the search for biochemical traces of life on other planets, part of this search involves an examination of amino acids, which are the building blocks of life on Earth. The most sensitive method for detecting amino acids is the use of laser induced fluorescence. However, since amino acids do not, in general, fluoresce, they first must be reacted with a fluorescent dye label prior to analysis. After this process is completed, the liquid sample then must be transported into the electrophoresis system. If the system is to be reused multiple times, samples must be added and removed each time. In typical laboratories, this process is performed manually by skilled human operators using standard laboratory equipment. This level of human intervention is not possible if this technology is to be implemented on extraterrestrial targets. Microchip capillary electrophoresis (CE) combined with laser induced fluorescence detection (LIF) was selected as an extremely sensitive method to detect amino acids and other compounds that can be tagged with a fluorescent dye. It is highly desirable to package this technology into an integrated, autonomous, in situ instrument capable of performing CE-LIF on the surface of an extraterrestrial body. However, to be fully autonomous, the CE device must be able to perform a large number of sample preparation and analysis operations without the direct intervention of a human.

Willis, Peter A.; Mora, Maria; Greer, Harold F.; Fisher, Anita M.; Bryant, Sherrisse

2012-01-01

419

New analytical portable instrument for microchip electrophoresis with electrochemical detection.  

PubMed

A new portable instrument that includes a high voltage power supply, a bipotentiostat, and a chip holder has been especially developed for using microchips electrophoresis with electrochemical detection. The main unit of the instrument has dimensions of 150 x 165 x 70 mm (wxdxh) and consists of a four-outputs high voltage power supply with a maximum voltage of +/-3 KV and an acquisition system with two channels for dual amperometric (DC or pulsed amperometric detection) detection. Electrochemical detection has been selected as signal transduction method because it is relatively easily implemented, since nonoptical elements are required. The system uses a lithium-ion polymer battery and it is controlled from a desktop or laptop PC with a graphical user interface based on LabVIEW connected by serial RS232 or Bluetooth. The last part of the system consists of a reusable chip holder for housing the microchips, which contain all the electrical connections and reservoirs for making the work with microchips easy. The performance of the new instrument has been evaluated and compared with other commercially available apparatus using single- and dual-channel pyrex microchips for the separation of the neurotransmitters dopamine, epinephrine, and 3,4-dihydroxy-L-phenyl-alanine. The reduction of the size of the instrument has not affected the good performance of the separation and detection using microchips electrophoresis with electrochemical detection. Moreover, the new portable instrument paves the way for in situ analysis making the use of microchips electrophoresis easier. PMID:20665922

Fernández-la-Villa, Ana; Pozo-Ayuso, Diego F; Castaño-Alvarez, Mario

2010-08-01

420

Separation and determination of quinolone antibacterials by capillary electrophoresis.  

PubMed

The migration behavior and separation of 13 quinolone antibacterials were investigated by capillary electrophoresis (CE). In order to predict the electrophoretic mobility, the protonation macroconstants of all the compounds were determined by pH-potentiometric titrations. We proved that the electrophoretic mobility of ionized quinolones (QNs) can be described with Offord's equation, and the migration order depends on their charge-to-mass ratios. A buffer of 25 mM sodium tetraborate adjusted to pH 9.3 was an efficient electrophoresis system for the separation of 12 QNs by capillary zone electrophoresis. This method can be considered a general method to separate quinolone derivatives. Ciprofloxacin, norfloxacin and ofloxacin, fluoroquinoles with very similar structural characteristics, were separated by micellar electrokinetic chromatography. Validation parameters, including linearity and detection and quantification limits, were also determined. Our results prove the applicability of CE for the simultaneous determination of QNs from complex mixtures. Our methods are environment-friendly replacement and improvement of a common high-performance liquid chromatography determination with rapid analysis time without using any organic solvents. PMID:23908264

Rusu, Aura; Hancu, Gabriel; Völgyi, Gergely; Tóth, Gerg?; Noszál, Béla; Gyéresi, Arpád

2014-09-01

421

Positive impact of biofilm on reducing the permeation of ampicillin through membrane for membrane bioreactor.  

PubMed

The membrane bioreactor (MBR) has recently been the focus of research for the treatment of emerging contaminants such as antibiotics in wastewater. Although the biofilm on membrane in an MBR has been considered a cause of "membrane biofouling", its positive impact on removing pollutants has not been well-studied. This study was designed to investigate the retention effect on the permeation of ampicillin (AMP) by the biofilm coated on cellulose acetate (CA) membrane (commonly used for MBRs) utilizing a novel method based on microbial sensitivity test. The bioflim layer (thickness of 12-16?m) increased the resistance of the membrane for AMP permeation by 3-28%. Diffusion appeared to be the main driving force for the mass transfer of AMP across the membrane. Besides, the biofilm increased the retention of AMP by 23% but exhibited similar adsorption capacity with comparison of the suspended activated sludge, which indicates that the compact structure of the biofilm was the major contributor for the added retention effect on AMP by the biofilm-coated CA membrane. This study suggests that biofilm (biofouling) in MBRs increases the retention of small-molecule constituents such as antibiotics. A delicate tradeoff between reduced wastewater throughput and increased retention of contaminants should be obtained when an MBR is designed and operated. PMID:24268345

Shen, Liang; Yuan, Xia; Shen, Weihuang; He, Ning; Wang, Yuanpeng; Lu, Haoliang; Lu, Yinghua

2014-02-01

422

76 FR 32366 - Determination That ORLAAM (Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams...  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and...Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams/Milliliter...acetate hydrochloride (HCl)) oral solution, 10 milligrams (mg...for levomethadyl acetate HCl oral solution, 10 mg/mL, if...

2011-06-06

423

Lipid membranes for membrane proteins.  

PubMed

The molecular dynamics (MD) simulation of membrane proteins requires the setup of an accurate representation of lipid bilayers. This chapter describes the setup of a lipid bilayer system from scratch using generally available tools, starting with a definition of the lipid molecule POPE, generation of a lipid bilayer, energy minimization, MD simulation, and data analysis. The data analysis includes the calculation of area and volume per lipid, deuterium order parameters, self-diffusion constant, and the electron density profile. PMID:25330959

Kukol, Andreas

2015-01-01

424

Selective Cross-Coupling of Organic Halides with Allylic Acetates  

PubMed Central

A general protocol for the coupling of haloarenes with a variety of allylic acetates is presented. Strengths of the method are a tolerance for electrophilic (ketone, aldehyde) and acidic (sulfonamide, trifluoroacetamide) substrates and the ability to couple with a variety of substituted allylic acetates. Secondary alkyl bromides can also be allylated under slightly modified conditions, demonstrating the generality of the approach. Finally, the coupling of a reactive vinyl halide could be achieved by the use of a very hindered ligand and more reactive, branched allylic acetates. PMID:23095043

Anka-Lufford, Lukiana L.; Prinsell, Michael R.

2012-01-01

425

Selective cross-coupling of organic halides with allylic acetates.  

PubMed

A general protocol for the coupling of haloarenes with a variety of allylic acetates is presented. Strengths of the method are a tolerance for electrophilic (ketone, aldehyde) and acidic (sulfonamide, trifluoroacetamide) substrates and the ability to couple with a variety of substituted allylic acetates. Secondary alkyl bromides can also be allylated under slightly modified conditions, demonstrating the generality of the approach. Finally, the coupling of a reactive vinyl halide could be achieved by the use of a very hindered ligand and more reactive, branched allylic acetates. PMID:23095043

Anka-Lufford, Lukiana L; Prinsell, Michael R; Weix, Daniel J

2012-11-16

426

Capillary zone electrophoresis method for the simultaneous determination of cations in honey.  

PubMed

A capillary electrophoresis system for the simultaneous determination of cations in honey samples has been developed. The complete separation and quantification of K+, Ca2+, Na+, Mg2+, Mn2+, Ni2+ and Li+, which represent more than 99% of the total content of cations in honey, can be achieved in 4 min with only a dilution and filtration of the honey sample. Electrolyte solution was composed by 10 mM imidazole as the carrier buffer and background absorbance provider and acetic acid as the complexing agent (pH 3.60). The running voltage was + 25 kV at 25 degree C. Indirect UV detection was achieved at 185 nm. Under the optimum conditions the detection limits ranged from 0.02 to 48.2 mg/kg and the quantification limits have ranged from 0.41 to 48.7 mg/kg. Precision data in honey samples analysed have shown repeatability and reproducibility RSD (%) lower than 2.84 and 6.62%, respectively. Recoveries of cations in honey samples analysed have ranged from 88.5 to 101.8%. These cations were identified by their relative migration times with regard to Ba2+ migration time used as reference standard and they were quantified by using an external standard calibration. Twenty-five honey samples were analysed to test the proposed method. Mean contents of 1.22 x 10(3), 93, 85, 54, 11, 1.9 and 2.3 mg/kg were found, respectively, for K+, Ca2+, Na+, Mg2+, Mn2+, Ni2+ and Li+ cations in analysed honeys. These results were similar than the obtained by other authors. PMID:16078707

Suárez-Luque, Silvia; Mato, Inés; Huidobro, José F; Simal-Lozano, Jesús

2005-08-12

427

Conformation Sensitive Gel Electrophoresis for Simple and Accurate Detection of Mutations: Comparison with Denaturing Gradient Gel Electrophoresis and Nucleotide Sequencing  

Microsoft Academic Search

Previously, an assay called conformation sensitive gel electrophoresis (CSGE) was developed for scanning PCR products for the presence of single-base and larger base mismatches in DNA. The assay was based on the assumption that mildly denaturing solvents in an appropriate buffer can accentuate the conformational changes produced by single-base mismatches in double-stranded DNA and thereby increase the differential migration in

Jarmo Korkko; Susanna Annunen; Tero Pihlajamaa; Darwin J. Prockop; Leena Ala-Kokko

1998-01-01

428

Adsorption characteristics of cellulose acetate coated charcoals.  

PubMed

The permeability of cellulose triacetate membrane coated activated charcoal is enhanced by treatment with KOH. The adsorption data for creatinine in aqueous solution before and after deacetylation are given. In order to study the usefulness of hemoperfusion associated with dialysis for removal of uremic toxins, some experiments were performed on the adsorption by coated and deacetylated charcoal of molecules of various molecular weights (from 113 to 40,000). Although the adsorption capacity of uncoated charcoal was better, the coated material still shows good properties in the adsorption of glucagon (mol wt 3485). The results on in vitro experiments of vitamin B12 removal by coated charcoal cartridge and CDAK Model 3 dialyzer confirms the usefulness of adsorption technique toward medium molecular weight compounds. PMID:1176475

Denti, E; Luboz, M P; Tessore, V

1975-03-01

429

A PROGESTOGEN (CHLORMADINONE ACETATE = CAP) FOR CYCLE CONTROL AND INFERTILITY  

E-print Network

A PROGESTOGEN (CHLORMADINONE ACETATE = CAP) FOR CYCLE CONTROL AND INFERTILITY TREATMENT IN THE MARE, CAP has been used for infertility treatments and cycle control in mares in Austria. In all indications

Paris-Sud XI, Université de

430

SOLVENT EXTRACTION OF WASTEWATERS FROM ACETIC-ACID MANUFACTURE  

EPA Science Inventory

Solvent extraction was evaluated as a potential treatment method for wastewaters generated during the manufacture of acetic acid. Possible goals for an extraction process were considered. For the wastewater samples studied, extraction appeared to be too expensive to be practical ...

431

Porphyria variegata treated with cyproterone acetate and ethinyl estradiol.  

PubMed

The cyclical use of cyproterone acetate and ethinyl estradiol successfully prevented attacks of abdominal pain in a 30-year-old woman suffering from porphyria variegata. Blistering still appeared following light exposure, but possibly to a lesser degree. PMID:6873421

Zachariae, H; Cramers, M

1983-01-01

432

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. PMID:23772396

Ahyayauch, Hasna; Sansar, Wafae; Rendón-Ramírez, Adela; Goñi, Félix M.; Bennouna, Mohammed; Gamrani, Halima

2013-01-01

433

Capillary electrophoresis and capillary electrophoresis-ion trap multiple-stage mass spectrometry for the differentiation and identification of oxycodone and its major metabolites in human urine.  

PubMed

Oxycodone (OCOD) and its metabolites, including oxymorphone (OMOR), noroxycodone (NOCOD) and noroxymorphone (NOMOR), are opioids that carry an OH group at position 14. Using capillary electrophoresis (CE) with a binary phosphate buffer containing 60% ethylene glycol (pH 7.9), the migration order of OCOD and OMOR with respect to their N-demethylated analogs was found to be reversed compared to that observed for codeine, dihydrocodeine, morphine and dihydromorphine, compounds that do not have an OH group at position 14. OCOD and structurally related compounds can also be distinguished from these opioids by their absorbance spectra at low wavelengths and via a characteristic neutral H2O loss at the MS2 level. Using the binary phosphate buffer, CE with UV detection is shown to be capable of monitoring OCOD, NOCOD, OMOR (after hydrolysis only) and NOMOR (after hydrolysis and in patient urine only) in alkaline liquid-liquid extracts of urines that were collected after ingestion of 10 mg OCOD hydrochloride and in a patient urine collected at steady state (80 mg OCOD hydrochloride daily). Using an aqueous pH 9 ammonium acetate buffer, these results were confirmed by CE-MS3. Based on CE-MS, MS2 and MS3 data, the absorbance spectra measured across the CE peaks and the relative position within the electropherogram, two peaks monitored in the UV absorbance electropherograms could be assigned to the two keto-reduced metabolites 6oxycodol (60COL) and nor6oxycodol, for which no standards were available. Comparison of data obtained with urines pretreated with two different enzyme products (beta-glucuronidase and beta-glucuronidase/arylsulfatase) suggest that OCOD, NOCOD and 6OCOL are mainly glucuronidated, whereas OMOR mainly forms other conjugates. Furthermore, in a first attempt to directly measure conjugates of the compounds of interest, solid-phase extracts were analyzed by CE-MS4, which revealed the presence of the acyl glucuronides of 6OCOL and OMOR and an unidentified OMOR conjugate. The quantitation of free OCOD and NOCOD by CE-MS using deuterated internal standards is also discussed briefly. PMID:12013227

Wey, Anita B; Thormann, Wolfgang

2002-04-25

434

Disposition of eslicarbazepine acetate in the mouse after oral administration.  

PubMed

Eslicarbazepine acetate is a promising antiepileptic drug structurally related to carbamazepine and oxcarbazepine, which is in the final phase of clinical development. The metabolism of eslicarbazepine acetate is clearly species dependent and, in this case, among small laboratory animals, the mouse seems to be the most relevant species to humans. Hence, the aim of this study was to investigate the plasma, brain and liver disposition of eslicarbazepine acetate in mice to better understand its disposition in humans. Adult male CD-1 mice were treated orally with a single dose of eslicarbazepine acetate 350 mg/kg. Blood samples, brain and liver tissues were taken at 0.25, 0.5, 0.75, 1, 2, 4, 6, 10, 16 and 24 h post-dose. Plasma and tissue levels of eslicarbazepine acetate and its metabolites (S-licarbazepine, R-licarbazepine and oxcarbazepine) were assessed by using high-performance liquid chromatography-ultraviolet detection. Both eslicarbazepine acetate and R-licarbazepine concentrations were below the limit of quantification of the assay in all matrices. Eslicarbazepine acetate was rapidly and extensively metabolized to S-licarbazepine (major metabolite), which was oxidized to oxcarbazepine to a small extent. The brain/plasma ratios suggest that the brain exposure to S-licarbazepine and oxcarbazepine was approximately 30% of their total systemic exposure. However, S-licarbazepine crossed the blood-brain barrier (BBB) less efficiently than oxcarbazepine. On the other hand, the liver/plasma ratios support the notion that S-licarbazepine undergoes hepatic accumulation, whereas oxcarbazepine appears to leave this compartment twice as fast as S-licarbazepine. Thus, the diffusion through the BBB is favourable to oxcarbazepine and the liver acts like a deposit of the pharmacologically active metabolite of eslicarbazepine acetate (S-licarbazepine). PMID:18710399

Alves, Gilberto; Figueiredo, Isabel; Castel-Branco, Margarida; Lourenço, Nulita; Falcão, Amílcar; Caramona, Margarida; Soares-da-Silva, Patrício

2008-10-01

435

Acetate transiently inhibits myocardial contraction by increasing mitochondrial calcium uptake.  

PubMed

BackgroundThere is a close relationship between cardiovascular disease and cardiac energy metabolism, and we have previously demonstrated that palmitate inhibits myocyte contraction by increasing Kv channel activity and decreasing the action potential duration. Glucose and long chain fatty acids are the major fuel sources supporting cardiac function; however, cardiac myocytes can utilize a variety of substrates for energy generation, and previous studies demonstrate the acetate is rapidly taken up and oxidized by the heart. In this study, we tested the effects of acetate on contractile function of isolated mouse ventricular myocytes.ResultsAcute exposure of myocytes to 10 mM sodium acetate caused a marked, but transient, decrease in systolic sarcomere shortening (1.49¿±¿0.20% vs. 5.58¿±¿0.49% in control), accompanied by a significant increase in diastolic sarcomere length (1.81¿±¿0.01 ¿m vs. 1.77¿±¿0.01 ¿m in control), with a near linear dose response in the 1¿10 mM range. Unlike palmitate, acetate caused no change in action potential duration; however, acetate markedly increased mitochondrial Ca2+ uptake. Moreover, pretreatment of cells with the mitochondrial Ca2+ uptake blocker, Ru-360 (10 ¿M), markedly suppressed the effect of acetate on contraction.ConclusionsLehninger and others have previously demonstrated that the anions of weak aliphatic acids such as acetate stimulate Ca2+ uptake in isolated mitochondria. Here we show that this effect of acetate appears to extend to isolated cardiac myocytes where it transiently modulates cell contraction. PMID:25488103

Schooley, James F; Namboodiri, Aryan M A; Cox, Rachel T; Bünger, Rolf; Flagg, Thomas P

2014-12-01

436

Acetic acid pulping of wheat straw under atmospheric pressure  

Microsoft Academic Search

Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were\\u000a investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw\\u000a was made of the chemical composition, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and\\u000a fractionated into pulp (cellulose),

Xue-Jun Pan; Yoshihiro Sano

1999-01-01

437

Microorganisms having enhanced resistance to acetate and methods of use  

SciTech Connect

The present invention provides isolated or genetically modified strains of microorganisms that display enhanced resistance to acetate as a result of increased expression of a sodium proton antiporter. The present invention also provides methods for producing such microbial strains, as well as related promoter sequences and expression vectors. Further, the present invention provides methods of producing alcohol from biomass materials by using microorganisms with enhanced resistance to acetate.

Brown, Steven D; Yang, Shihui

2014-10-21

438

Permeation study of five formulations of alpha-tocopherol acetate through human cadaver skin.  

PubMed

Alpha-tocopherol (AT) is the vitamin E homologue with the highest in vivo biological activity. AT protects against the carcinogenic and mutagenic activity of ionizing radiation and chemical agents, and possibly against UV-induced cutaneous damage. For stability consideration, alpha-tocopherol is usually used as its prodrug ester, alpha-tocopherol acetate (ATA), which once absorbed into the skin is hydrolyzed to alpha-tocopherol, the active form. The objective of this research was to characterize in vitro the permeation properties of ATA from various solutions and gel formulations. Permeation studies were conducted using modified Franz diffusion cells and human cadaver skin as the membrane. Specifically, 5% (w/w) alpha-tocopherol acetate was formulated in the following vehicles: ethanol, isopropyl myristate, light mineral oil, 1% Klucel gel in ethanol, and 3% Klucel gel in ethanol (w/w). The receiver temperature was 37 degrees C. Samples from the receiver were collected at 2, 4, 6, 8, 12, 24, 30, 36, and 48 hours and analyzed by HPLC for concentrations of alpha-tocopherol acetate and alpha-tocopherol. The permeabilities of ATA through human cadaver skin were 1.0x10(-4), 1.1x10(-2), 1.4x10(-4), 2.1x10(-4), and 4.7x10(-4) cm/h for the ethanol solution, isopropyl myristate solution, light mineral oil solution, 1% Klucel gel, and 3% Klucel gel, respectively. The results show that the formulation had relatively minor effects on the permeability coefficients of ATA through cadaver skin in all cases except for the isopropyl myristate solution. PMID:15868062

Mahamongkol, Hansa; Bellantone, Robert A; Stagni, Grazia; Plakogiannis, Fotios M

2005-01-01

439

Magnetic Membrane System  

DOEpatents

The present invention provides a membrane with magnetic particles. In one embodiment the membrane is created by mixing particles in a non-magnetic base. The membrane may act as an actuator, a sensor, a pump, a valve, or other device. A magnet is operatively connected to the membrane. The magnet acts on and changes the shape of the membrane.

McElfresh, Michael W.; (Livermore, CA); Lucas, Matthew S.; (Pasadena, CA)

2004-12-30

440

Identification of cytoplasmic membrane protein antigens of Mycobacterium avium, M. intracellulare, and M. scrofulaceum.  

PubMed

The cytoplasmic membrane isolated from representative strains of the Mycobacterium avium, M. intracellulare, and M. scrofulaceum (MAIS) group contained approximately 20 proteins, as identified by SDS - polyacrylamide gel electrophoresis. One membrane protein predominated, comprising up to 50% of the total membrane protein. This major cytoplasmic membrane protein (MCMP) had a molecular weight of 31,000 and was surface accessible based on its susceptibility to proteinase digestion. The composition of the culture medium strongly influenced the amount of MCMP in the membrane fraction. Western blot analysis revealed that the MCMP and several other membrane proteins reacted with serum samples from patients infected with M. avium-intracellulare, M. tuberculosis, or other mycobacteria. PMID:2743223

George, K L; Falkinham, J O

1989-05-01

441

Challenges and solutions for the identification of membrane proteins in non-model plants.  

PubMed

The workhorse for proteomics in non-model plants is classical two-dimensional electrophoresis, a combination of iso-electric focusing and SDS-PAGE. However, membrane proteins with multiple membrane spanning domains are hardly detected on classical 2-DE gels because of their low abundance and poor solubility in aqueous media. In the current review, solutions that have been proposed to handle these two problems in non-model plants are discussed. An overview of alternative techniques developed for membrane proteomics is provided together with a comparison of their strong and weak points. Subsequently, strengths and weaknesses of the different techniques and methods to evaluate the identification of membrane proteins are discussed. Finally, an overview of recent plant membrane proteome studies is provided with the used separation technique and the number of identified membrane proteins listed. PMID:21354347

Vertommen, A; Panis, B; Swennen, R; Carpentier, S C

2011-08-12

442

The study on pervaporation behaviors of dilute organic solution through PDMS/PTFE composite membrane.  

PubMed

As an energy-efficient alternative to distillation, pervaporation has been widely combined with fermentation to remove organic compounds from their dilute solutions in a fermentation broth. In this work, the organic permselective composite membrane is prepared by coating polydimethylsiloxane (PDMS) cross-linked with n-heptane on the substrate of polytetrafluoroethylene(PTFE) membrane. The separation behavior is studied in different dilute organic solutions, which include acetone dilute solution, butanone dilute solution, cyclohexanone dilute solution, ethanol dilute solution, isopropanol dilute solution, n-butyl alcohol dilute solution, acetic acid dilute solution, and ethyl acetate dilute solution. Most of these solutions are main reaction products or by-products from fermentation process. The effects of solubility of organics in the membrane, molecular weight, and polarity of the organics on the pervaporation performance are investigated. The effects of operating temperature and organic concentration in the feed solutions on the performance of composite membrane are studied as well. The experimental results show that molecular volume has less influence than solubility and molecular polarity for these organic solvent. The selectivity of PDMS membrane to ethyl acetate is relative high due to good solubility and diffusion of ethyl acetate molecules in polymer. PMID:19259826

Zhang, Wei-dong; Sun, Wei; Yang, Jing; Ren, Zhong-qi

2010-01-01

443

Integrated allele-specific polymerase chain reaction-capillary electrophoresis microdevice for single nucleotide polymorphism genotyping.  

PubMed

An integrated allele-specific (AS) polymerase chain reaction (PCR) and capillary electrophoresis (CE) microdevice has been developed for multiplex single nucleotide polymorphism (SNP) genotyping on a portable instrumentation, which was applied for on-site identification of HANWOO (Korean indigenous beef cattle). Twelve sets of primers were designed for targeting beef cattle's eleven SNP loci for HANWOO verification and one primer set for a positive PCR control, and the success rate for identification of HANWOO was demonstrated statistically. The AS PCR and CE separation for multiplex SNP typing was carried out on a glass-based microchip consisting of four layers: a microchannel plate for microfluidic control, a Pt-electrode plate for a resistance temperature detector (RTD), a poly(dimethylsiloxane) (PDMS) membrane and a manifold glass for microvalve function. The operation of the sample loading, AS PCR, microvalve, and CE on a chip was automated with a portable genetic analyzer, and the laser-induced fluorescence detection was performed on a miniaturized fluorescence detector. The blind samples were correctly identified as a HANWOO by showing one or two amplicon peaks in the electropherogram, while the imported beef cattle revealed more than five peaks. Our genetic analysis platform provides rapid, accurate, and on-site multiplex SNP typing. PMID:22464916

Choi, Jong Young; Kim, Yong Tae; Ahn, Jinwoo; Kim, Kwan Suk; Gweon, Dae-Gab; Seo, Tae Seok

2012-05-15

444

Experimental and theoretical investigation of the stability of stepwise pH gradients in continuous flow electrophoresis  

NASA Technical Reports Server (NTRS)

Isoelectric focusing in the continuous flow mode can be more quickly and economically performed by admitting a stepwise pH gradient composed of simple buffers instead of uniform mixtures of synthetic carrier ampholytes. The time-consuming formation of the pH gradient by the electric field is thereby omitted. The stability of a three-step system with arginine - morpholinoethanesulfonic acid/glycylglycine - aspartic acid is analyzed theoretically by one-dimensional computer simulation as well as experimentally at various flow rates in a continuous flow apparatus. Excellent agreement between experimental and theoretical data was obtained. This metastable configuration was found to be suitable for focusing of proteins under continuous flow conditions. The influence of various combinations of electrolytes and membranes between electrophoresis chamber and electrode compartments is also discussed.

Kuhn, Reinhard; Wagner, Horst; Mosher, Richard A.; Thormann, Wolfgang

1987-01-01

445

Highly conductive ethylene-vinyl acetate copolymer/carbon nanotube paper for lightweight and flexible supercapacitors  

NASA Astrophysics Data System (ADS)

Herein, we developed a highly conductive and lightweight membrane substrate based on the ethylene-vinyl acetate copolymer (EVA), carbon nanotubes (CNTs) and lens wiping paper, and demonstrated its implementation as high-performance mechanical support for MnO2 in supercapacitors. The 45 s-MnO2/EVA/40 wt%CNT electrode exhibited a high capacitance (0.126 F cm-2 at 0.5 mA cm-2) with excellent flexibility. Furthermore, the fabricated devices based on these 45 s-MnO2/EVA/40 wt%CNT electrodes exhibited excellent flexibility and stability (85% of its initial capacitance retained after 800 bending cycles) and achieved a high energy density of 9.4 Wh kg-1 at 6780 W kg-1.

Zhang, Zishou; Wang, Wang; Li, Cheng; Wei, Lin; Chen, Xiaojun; Tong, Yexiang; Mai, Kancheng; Lu, Xihong

2014-02-01

446

Ionic liquid assisted electrospun cellulose acetate fibers for aqueous removal of triclosan.  

PubMed

The cellulose acetate (CA) membrane prepared via electrospun was innovatively utilized as fiber-adsorbent for the separation of aqueous triclson (TCS). It was found that the presence of the room temperature ionic liquid (RTIL) in the precursor amplified electric force toward the CA-solution, thereby benefiting the formation of CA fibers. The as-spun CA fibers exhibit excellent adsorptive performance toward TCS, with fast adsorption kinetics, and the maximum adsorption capacity achieved to 797.7 mg g(-1), which established much better performance in contrast to conventional adsorbents. We proposed that the adsorption of TCS onto CA fibers was primarily facilitated by the hydrogen bonding between the abundant carbonyl, hydroxyl groups of CA surface, and the hydrogen atoms of phenol functional groups in TCS molecular. PMID:25595432

Zhang, Gong; Sun, Meng; Liu, Yang; Liu, Huijuan; Qu, Jiuhui; Li, Jinghong

2015-02-10

447

The effect of uranyl acetate on human lymphoblastoid cells (RPMI 6410) and HeLa cells.  

PubMed Central

RPMI 6410 cells and HeLa cells were exposed to uranyl acetate. In RPMI 6410 cell cultures this produced single-membrane-bound presumably lysosomal bodies (called "uraniosomes") containing electron-dense crystals in the cultured cells and crystalline deposits in extracellular locations. Neither uraniosomes nor extracellular uranium deposits were found in HeLa cell cultures. All uraniosomes and extracellular uranium deposits analysed by electron-probed X-ray analysis were found to contain uranium, potassium and phosphorus. Traces of sulphur were detected in some but not all uraniosomes and extracellular uranium deposits. Traces of calcium were found in all extracellular uranium deposits and in some uraniosomes also. Images Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7093141

Ghadially, F. N.; Yang-Steppuhn, S. E.; Lalonde, J. M.

1982-01-01

448

Reactivity of some sugars and sugar phosphates towards gold(III) in sodium acetate–acetic acid buffer medium  

Microsoft Academic Search

The kinetics of the oxidation of some aldoses and aldose phosphates have been studied spectrophotometrically in sodium acetate–acetic acid buffer medium at different temperatures. The reactions are first order with respect to [Au(III)] and [substrate]. Both H+ and Cl? ions retard the reaction. The reactions appear to involve different gold(III) species, viz. AuCl4?, AuCl3(OH2) and AuCl3(OH)?. The results are interpreted

Kalyan Kali Sen Gupta; Biswajit Pal; Bilkis Ara Begum

2001-01-01

449

Analysis of five alkaloids using surfactant-coated multi-walled carbon nanotubes as the pseudostationary phase in nonaqueous capillary electrophoresis.  

PubMed

In this paper, surfactant-coated multi-walled carbon nanotubes (SC-MWNTs) have been proposed as a novel pseudostationary phase (PSP) to enhance the separation of isoquinoline alkaloids in nonaqueous capillary electrophoresis (NACE). Several parameters affecting NACE separation were studied including the MWNT concentration, the electrolyte concentration, pH* and the separation voltage. In comparison to conventional NACE, the addition of an MWNT dispersion using surfactant solutions in the electrolyte produced an important enhancement in the resolution due to the ?-? interactions between the analytes and the surface of the carbon nanotubes. Using SC-MWNTs (6?gmL(-1)) as a PSP in the background electrolyte (BGE) (i.e., 20mM sodium acetate in methanol-acetonitrile (80:20, v/v)) provided the complete separation of five alkaloids. Finally, the developed method has been successfully applied to the detection and quantification of the tested compounds of Rhizoma Coptidis. PMID:24720903

Hou, Jingyi; Li, Geng; Wei, Yingqin; Lu, Heng; Jiang, Chao; Zhou, Xiaoteng; Meng, Fanyun; Cao, Jun; Liu, Jinxin

2014-05-23

450

A hybrid microdevice for electrophoresis and electrochromatography using UV detection.  

PubMed

We have designed a new class of microdevices composed of a supporting plastic (polyvinyl chloride, PVC) plate integrated with a groove for a piece of fused silica capillary (the separation channel), a slit for on-tube detection, an "islet" for the application of sample, electrode vessels and platinum electrodes. The design permits electrophoretic, electrochromatographic and chromatographic separations with on-tube UV detection. The efficient heat dissipation allows relatively high field strengths. This article is the first one dealing with microdevices where polymer solutions are replaced by homogeneous gels. A new type of gels synthesized from acrylamide and 2-hydroxy-3-allyloxy-propyl-beta-cyclodextrin (allyl-beta-CD) as a cross-linker was employed for electrophoresis and electrochromatography. 2-Acrylamido-2-methylpropanesulfonic acid was added to the monomer solution to create a high electroendosmotic flow in electrochromatographic runs. These gels have excellent electrochromatographic and electrophoretic properties for low-molecular-weight compounds and DNA, as shown previously, namely high resolution combined with high stability. The unique cross-linker can be used for specific interaction with the alkyl and phenyl groups. The tripeptide glutathione (gamma-L-glutamyl-L-cysteinyl-glycine) and its benzyl conjugates were selected as model compounds to study the resolving power of the gel because they are difficult to separate by free zone electrophoresis. The limit of detection (LOD) for S-benzyl-glutathione was determined (ca. 7 microM). Run-by-run reproducibility was high (the separation factor of glutathione in the gel was 0.3 with 2.5% coefficient of variation, CV). Neutral compounds (acetone, acetophenone, propiophenone and butyrophenone) were separated electrochromatographically in the gel. The influence of organic solvent (acetonitrile) on the electroendosmotic mobility was similar to that in reversed-phase separations, although the separation mechanism is different. ATP, ADP and AMP were separated in less than 10 s by free-zone electrophoresis. PMID:12412115

Végvári, Akos; Hjertén, Stellan

2002-10-01

451

Controlling two-dimensional tethered vesicle motion using an electric field: interplay of electrophoresis and electro-osmosis.  

PubMed

We recently introduced methods to tether phospholipid vesicles or proteoliposomes onto a fluid-supported lipid bilayer using DNA hybridization (Yoshina-Ishii, C.; Miller, G. P.; Kraft, M. L.; Kool, E. T.; Boxer, S. G. J. Am. Chem. Soc. 2005, 127, 1356-1357). These intact tethered vesicles diffuse in two dimensions parallel to the supporting membrane surface. In this article, we report the dynamic response of individual tethered vesicles to an electric field applied parallel to the bilayer surface. Vesicles respond to the field by moving in the direction of electro-osmotic flow, and this can be used to reversibly concentrate tethered vesicles against a barrier. By adding increasing amounts of negatively charged phosphatidylserine to the supporting bilayer to increase electro-osmosis, the electrophoretic mobility of the tethered vesicles can be increased. The electro-osmotic contribution can be modeled well by a sphere connected to a cylindrical anchor in a viscous membrane with charged headgroups. The electrophoretic force on the negatively charged tethered vesicles opposes the electro-osmotic force. By increasing the amount of negative charge on the tethered vesicle, drift in the direction of electro-osmotic flow can be slowed; at high negative charge on the tethered vesicle, motion can be forced in the direction of electrophoresis. The balance between these forces can be visualized on a patterned supporting bilayer containing negatively charged lipids that reorganize in an externally applied electric field to create a gradient of charge within a corralled region. The charge gradient at the surface creates a gradient of electro-osmotic flow, and vesicles carrying similar amounts of negative charge can be focused to a region perpendicular to the applied field where electrophoresis is balanced by electro-osmosis, away from the corral boundary. Electric fields are effective tools to direct tethered vesicles and concentrate them and to measure the tethered vesicle's electrostatic properties. PMID:16489833

Yoshina-Ishii, Chiaki; Boxer, Steven G

2006-02-28

452

A study of cell electrophoresis as a means of purifying growth hormone secreting cells  

NASA Technical Reports Server (NTRS)

Growth hormone secreting cells of the rat anterior pituitary are heavily laden with granules of growth hormone and can be partialy purified on the basis of their resulting high density. Two methods of preparative cell electrophoresis were investigated as methods of enhancing the purification of growth hormone producing cells: density gradient electrophoresis and continuous flow electrophoresis. Both methods provided a two- to four-fold enrichment in growth hormone production per cell relative to that achieved by previous methods. Measurements of electrophoretic mobilities by two analytical methods, microscopic electrophoresis and laser-tracking electrophoresis, revealed very little distinction between unpurified anterior pituitary cell suspensions and somatotroph-enriched cell suspensions. Predictions calculated on the basis of analytical electrophoretic data are consistent with the hypothesis that sedimentation plays a significant role in both types of preparative electrophoresis and the electrophoretic mobility of the growth hormone secreting subpopulation of cells remains unknown.

Plank, Lindsay D.; Hymer, W. C.; Kunze, M. Elaine; Marks, Gary M.; Lanham, J. Wayne

1983-01-01

453

Membrane Systems in Cyanobacteria  

SciTech Connect

Cyanobacteria are photosynthetic prokaryotes with highly differentiated membrane systems. In addition to a Gram-negative-type cell envelope with plasma membrane and outer membrane separated by a periplasmic space, cyanobacteria have an internal system of thylakoid membranes where the fully functional electron transfer chains of photosynthesis and respiration reside. The presence of different membrane systems lends these cells a unique complexity among bacteria. Cyanobacteria must be able to reorganize the membranes, synthesize new membrane lipids, and properly target proteins to the correct membrane system. The outer membrane, plasma membrane, and thylakoid membranes each have specialized roles in the cyanobacterial cell. Understanding the organization, functionality, protein composition and dynamics of the membrane systems remains a great challenge in cyanobacterial cell biology.

Liberton, Michelle L.; Pakrasi, Himadri B.

2008-01-01

454

The fluid mechanics of continuous flow electrophoresis in perspective  

NASA Technical Reports Server (NTRS)

Buoyancy alters the flow in continuous flow electrophoresis chambers through the mechanism of hydrodynamic instability and, when the instability is supressed by careful cooling of the chamber boundaries, by restructuring the axial flow. The expanded roles of buoyancy follow upon adapting the size of the chamber and the electric field so as to fractionate certain sorts of cell populations. Scale-up problems, hydrodynamic stability and the altered flow fields are discussed to show how phenomena overlooked in the design and operations of narrow-gap devices take on an overwhelming importance in wide-gap chambers

Saville, D. A.

1980-01-01

455

Comparison of properties of agarose for electrophoresis of DNA.  

PubMed

Agarose as a medium for separation of DNA was first introduced in 1962 and since the early 1970s agarose submarine gel electrophoresis has been synonymous with separations of DNA molecules larger than 1 kilobase pair (kb). The large pore size, low electroendosmosis and strength of the matrix have advantages over other media such as polyacrylamide for many applications. The variety of grades of agarose, developed by chemical manipulation of the substitutions on the agarose polymer, provides a range of matrices for separation of DNA molecules from a few base pairs (bp) to over 5 megabase pairs (Mb) in length. The introduction of low-melting-temperature agarose has revolutionised the extraction and manipulation of chromosome-sized molecules. On the other hand, the demand for analysis of very small quantities of DNA will most likely lead to the increasing importance of capillary electrophoresis. Many theories have been propounded to explain the electrophoretic migration of DNA in agarose. The most popular of these has been reptation theory but none can account for all of the reported anomalies in migration. However, anomalous migration has been exploited to study DNA structure, topology and catenation. An example of the use of two-dimensional electrophoresis to demonstrate the complexity of DNA migration through agarose is given. Generally, for molecules smaller than 50 kb, electrophoretic separation is a function of length. By alternately electrophoresing DNA in two different directions, molecules as large as 5.7 Mb have been effectively separated, although with such large molecules DNA structure as well as size may determine migration. In the case of separations of chromosomes from the intestinal protozoan, Giardia duodenalis, for example, a discrepancy of 1 Mb in the size of one chromosome, with an apparent size of 0.7-2.0 Mb, depended on the boundary conditions of separation. Major challenges for the molecular biologist are separation of larger chromosomal sized molecules, greater number of samples and smaller formats. Towards this challenge computer-aided technology is a key component in the control of electrophoresis parameters and analysis. PMID:8227266

Upcroft, P; Upcroft, J A

1993-08-25

456

Determination of benzylpenicillin in pharmaceuticals by capillary zone electrophoresis  

SciTech Connect

A rapid and direct method is described for the determination of benzylpenicillin (penicillin G) in pharmaceutical preparations. The method involves very little sample preparation and total analysis time for duplicate results is less 30 minutes per sample. The method takes advantage of the speed and separating power of capillary zone electrophoresis (CZE). Detection of penicillin is by absorption at 228 nm. An internal standard is employed to reduce sample injection error. The method was applied successfully to both tablets and injectable preparations. 14 refs., 5 figs., 3 tabs.

Hoyt, A.M. Jr. (Univ. of Central Arkansas, Conway (USA)); Sepaniak, M.J. (Univ. of Tennessee, Knoxville (USA))

1989-04-01

457

Determination of volatile corrosion inhibitors by capillary electrophoresis  

Microsoft Academic Search

In this work, a capillary electrophoresis (CE) method using indirect UV detection (214nm) for the simultaneous determination of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), diethylethanolamine (DEEA), monocyclohexylamine (MCHA) and dicyclohexylamine (DCHA) in water\\/ethanol extracts of wrapping materials containing volatile corrosion inhibitors (VCIs) was described. A running buffer consisting of 0.010molL?1 imidazole, 0.010molL?1 2-hydroxyisobutyric acid (HIBA) and 0.010molL?1 18-crown-6 ether enabled

Elisabete A. Pereira; Marina F. M. Tavares

2004-01-01

458

Electrophoresis in charge-stabilized colloidal cluster phases.  

PubMed

The reversible properties of cluster phases have been described by theories that invoke Coulomb interactions as a stabilizing mechanism. What is lacking so far is direct measurement of these charges. This contribution aims at predicting what to expect if electrophoresis measurements were to be performed on these systems. As a result, we get a picture that exhibits several interesting features: (1) The existence of monomers and clusters lead to distinctly different mobilities (zeta potentials) in a single sample. (2) Strong dependence of the mobilities on particle volume fraction. It is our aim that the theory outlined in this paper may serve as a guideline to interpret the expectedly "messy" electrophoretic measurements. PMID:21520976

Groenewold, Jan; Zhang, Tianhui; Kegel, Willem K

2011-06-01

459

Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries  

SciTech Connect

Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)

Wahl, J.H.; Goodlett, D.R.; Udseth, H.R.; Smith, R.D.

1992-06-01

460

Determination of the artificial sweetener Sucralose® by capillary electrophoresis  

Microsoft Academic Search

The artificial intense sweetener 1,6-dichloro-1,6-dideoxy-?-D-fructofuranosyl-4-chloro-4-deoxy-?-D-galactopyranose (Sucralose®) was determined by capillary electrophoresis with indirect ultraviolet absorption in a 3,5-dinitrobenzoic acid buffer at pH 12.1. The method allowed determination of Sucralose in low-calorie soft drinks, without any sample clean-up over a linear range of 42–1000 mg l (r=0.9991). The limits of detection and determination were 28 and 42 mg l, respectively, and

J. Stroka; N. Dossi; E. Anklam

2003-01-01

461

Capillary electrophoresis-electrochemical detection microchip device and supporting circuits  

SciTech Connect

The present invention is a capillary electrophoresis device, comprising a substrate; a first channel in the substrate, and having a buffer arm and a detection arm; a second channel in the substrate intersecting the first channel, and having a sample arm and a waste arm; a buffer reservoir in fluid communication with the buffer arm; a waste reservoir in fluid communication with the waste arm; a sample reservoir in fluid communication with the sample arm; and a detection reservoir in fluid communication with the detection arm. The detection arm and the buffer arm are of substantially equal length.

Jackson, Douglas J. (New Albany, IN); Roussel, Jr., Thomas J. (Louisville, KY); Crain, Mark M. (Georgetown, IN); Baldwin, Richard P. (Louisville, KY); Keynton, Robert S. (Louisville, KY); Naber, John F. (Prospect, KY); Walsh, Kevin M. (Louisville, KY); Edelen, John. G. (Versailles, KY)

2008-03-18

462

Comparative gel electrophoresis analysis of helical junctions in RNA.  

PubMed

Comparative gel electrophoresis provides information on the relative angles subtended between helical arms at a branchpoint in RNA. It is based upon the comparison of electrophoretic mobility in polyacrylamide gels of species containing two long arms, with the remaining one(s) being significantly shorter. Although the method currently lacks a really well-established basis of physical theory, it is very powerful, yet simple to apply. It has had a number of significant successes in RNA, DNA and DNA-protein complexes, and in all cases to date the results have stood the test of time and eventual comparison with crystallographic analysis. PMID:20946788

Lilley, David M J

2009-01-01

463

Recent developments in capillary electrophoresis of carbohydrate species.  

PubMed

Carbohydrates are ubiquitous species involved in many life processes. Because of the multilateral roles of carbohydrates, their analysis has come to have increasing importance. As shown in this review, capillary electrophoresis in its various modes of operation has proved very useful in the analysis of carbohydrate species including mono- and oligosaccharides, glycoproteins, glycopeptides and glycosaminoglycans. Advances in separation approaches and applications as well as advances in detection including sensitive and selective pre-column derivatization are described. In summary, this comprehensive review is a supplement to previous reviews and covers the published work in 1996 and the first half of 1997. PMID:9456054

El Rassi, Z

1997-11-01

464

Density gradient electrophoresis of cultured human embryonic kidney cells  

NASA Technical Reports Server (NTRS)

Ground based confirmation of the electrophoretic heterogeneity of human embryonic kidney cell cultures, the general characterization of their electrophoretic migration, and observations on the general properties of cultures derived from electrophoretic subpopulations were studied. Cell migration in a density gradient electrophoresis column and cell electrophoretic mobility was determined. The mobility and heterogeneity of cultured human embryonic kidney cells with those of fixed rat erythrocytes as model test particle was compared. Electrophoretically separated cell subpopulations with respect to size, viability, and culture characteristics were examined.

Plank, L. D.; Kunze, M. E.; Giranda, V.; Todd, P. W.

1985-01-01

465

DNA electrophoresis in a sparse ordered post array  

NASA Astrophysics Data System (ADS)

We present a study of the electrophoresis of long DNA in a strong electric field through a hexagonal array of cylindrical microscale posts spaced such that the pore size is commensurate with equilibrium coil size of the DNA. Experimental mobility, dispersivity, and videomicroscopy data indicate that the DNA frequently collide with the posts, contradicting previous Brownian dynamics studies using a uniform electric field. We demonstrate via simulations that the frequent collisions, which are essential to separations in these devices, are due to the nonuniform electric field, highlighting the importance of accounting for electric-field gradients when modeling DNA transport in microfluidic devices.

Ou, Jia; Cho, Jaeseol; Olson, Daniel W.; Dorfman, Kevin D.

2009-06-01

466

Capillary electrophoresis: Biotechnology for separation of DNA and chromosomes  

NASA Technical Reports Server (NTRS)

Electrophoresis has been used for the separation of particles, ions, and molecules for a number of years. The technology for separation and detection of the results has many applications in the life sciences. One of the major goals of the scientific community is to separate DNA molecules and intact chromosomes based upon their different lengths or number of base pairs. This may be achieved by using some of the commercially available and widely used methods, but these processes require a considerable amount of time. The challenge is to achieve separation of intact chromosomes in a short time, preferably in a matter of minutes.

Williams, George O., Jr.

1994-01-01

467

Improvements to polar 2-D electrophoresis for proteomic applications.  

PubMed

Recently, we reported a new way of performing 2-DE, called P-dimensional electrophoresis (2-PE). In this approach, the second dimension is achieved in a radial gel which can accommodate up to six 7 cm long IPG strips simultaneously, improving reproducibility and throughput power in respect to 2-DE. Nevertheless, 2-PE was up to now limited to the use of only short strips because of technical difficulties. Here, we describe how to load longer strips (e.g., 18-24 cm) on 2-PE and report some representative images for a qualitative assessment. PMID:24459004

Polati, Rita; Cecconi, Daniela; Dosselli, Ryan; Zaccarin, Mattia; Millioni, Renato

2014-04-01

468

Tetrazole acetic acid: Tautomers, conformers, and isomerization  

SciTech Connect

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0–8 kJ mol{sup ?1} energy range and should be appreciably populated at the sublimation temperature (?330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol{sup ?1}) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol{sup ?1}). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm{sup ?1}, where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm{sup ?1}, transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N{sub 2} matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO{sub 2} and 5-methyl-tetrazole, is proposed.

Araujo-Andrade, C. [Unidad Académica de Física de la Universidad Autónoma de Zacatecas, Zacatecas (Mexico) [Unidad Académica de Física de la Universidad Autónoma de Zacatecas, Zacatecas (Mexico); Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Reva, I., E-mail: reva@qui.uc.pt; Fausto, R. [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal)] [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal)

2014-02-14

469

Intensified membrane filtration with corrugated membranes  

Microsoft Academic Search

Crossflow membrane microfiltration of 30% (w\\/w) water-in-oil emulsions is reported using hydrophobic PVDF and PTFE membranes. The flux performance of corrugated membranes is compared with that of flat membranes. The influence of crossflow velocity (CFV), flow channel height and transmembrane pressure (TMP) were investigated. The effect of varying the angle of corrugation (between the flow direction and the corrugation) on

K Scott; A. J Mahmood; R. J Jachuck; B Hu

2000-01-01

470

Applications of capillary electrophoresis in DNA mutation analysis of genetic disorders.  

PubMed Central

AIM: To facilitate DNA mutation analysis by use of capillary electrophoresis. METHODS: The usefulness and applications of capillary electrophoresis in DNA fragment sizing and sequencing were evaluated. RESULTS: DNA mutation testing in disorders such as cystic fibrosis, Huntington disease, alpha thalassaemia, and hereditary fructose intolerance were undertaken effectively. However, sizing the (CAG)n repeat in the case of Huntington disease was a potential problem when using capillary electrophoresis. Separation polymers used in capillary electrophoresis are still in the developmental phase, with improved ones being released regularly. CONCLUSIONS: In the DNA diagnostic setting, capillary electrophoresis is a valuable development because it expands the scope for automation and has useful analytical properties. The potential to perform complex multiplexing within one electrophoresis run facilitates DNA diagnosis. The different mobility of DNA fragments in capillary electrophoresis compared with conventional gel electrophoresis will require, in some circumstances, additional care when results are being interpreted or reported. Capillary electrophoresis is a cheap alternative for combined automated sequencing and fragment analysis that utilises multicolour fluorescence capability. However, in its present form, it is not useful for large scale sequencing. PMID:9497917

Le, H; Fung, D; Trent, R J

1997-01-01

471

Studies on proteinograms in dermatorphytes by disc electrophoresis. Part 2: Protein bands of keratinophilic fungi  

NASA Technical Reports Server (NTRS)

Disc electrophoresis studies on keratinophili fungi demonstrated corresponding proteinograms in morphologically homogeneous strains of the same species, but different in different species of one and the same genus.

Danev, P.; Balabanov, V.; Friedrich, E.

1983-01-01

472

Experimental study of the hydrothermal reactivity of organic acids and acid anions: II. Acetic acid, acetate, and valeric acid  

NASA Astrophysics Data System (ADS)

Organic acids and acid anions occur in substantial concentrations in many aqueous geologic fluids and are thought to take part in a variety of geochemical processes ranging from the transport of metals in ore-forming fluids to the formation of natural gas to serving as a metabolic energy source for microbes in subsurface habitats. The widespread occurrence of organic acids and their potential role in diverse geologic processes has led to numerous experimental studies of their thermal stability, yet there remain substantial gaps in our knowledge of the factors that control the rates and reaction pathways for the decomposition of these compounds under geologic conditions. In order to address some of these uncertainties, a series of laboratory experiments were conducted to examine the behavior of organic acids and acid anions under hydrothermal conditions in the presence of minerals. Reported here are results of experiments where aqueous solutions of acetic acid, sodium acetate, or valeric acid ( n-pentanoic acid) were heated at 325°C, 350 bars in the presence of the mineral assemblages hematite + magnetite + pyrite, pyrite + pyrrhotite + magnetite, and hematite + magnetite. The results indicate that aqueous acetic acid and acetate decompose by a combination of two reaction pathways: decarboxylation and oxidation. Both reactions are promoted by minerals, with hematite catalyzing the oxidation reaction while magnetite catalyzes decarboxylation. The oxidation reaction is much faster, so that oxidation dominates the decomposition of acetic acid and acetate when hematite is present. In contrast to previous reports that acetate decomposed more slowly than acetic acid, we found that acetate decomposed at slightly faster rates than the acid in the presence of minerals. Although longer-chain monocarboxylic acids are generally thought t