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Sample records for specific membrane depths

  1. Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane

    Energy Technology Data Exchange (ETDEWEB)

    Vaish, Amit, E-mail: anv@udel.edu; Krueger, Susan; Dimitriou, Michael; Majkrzak, Charles [National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, MD 20899-8313 (United States); Vanderah, David J. [Institute for Bioscience and Biotechnology Research, NIST, Rockville, Maryland 20850 (United States); Chen, Lei, E-mail: lei.chen@nist.gov [NIST Center for Nanoscale Science and Technology, Gaithersburg, Maryland 20899-8313 (United States); Gawrisch, Klaus [Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892 (United States)

    2015-01-15

    Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface.

  2. Topology and immersion depth of an integral membrane protein by paramagnetic rates from dissolved oxygen.

    Science.gov (United States)

    Al-Abdul-Wahid, M Sameer; Verardi, Raffaello; Veglia, Gianluigi; Prosser, R Scott

    2011-09-01

    In studies of membrane proteins, knowledge of protein topology can provide useful insight into both structure and function. In this work, we present a solution NMR method for the measurement the tilt angle and average immersion depth of alpha helices in membrane proteins, from analysis of the paramagnetic relaxation rate enhancements arising from dissolved oxygen. No modification to the micelle or protein is necessary, and the topology of both transmembrane and amphipathic helices are readily determined. We apply this method to the measure the topology of a monomeric mutant of phospholamban (AFA-PLN), a 52-residue membrane protein containing both an amphipathic and a transmembrane alpha helix. In dodecylphosphocholine micelles, the amphipathic helix of AFA-PLN was found to have a tilt angle of 87° ± 1° and an average immersion depth of 13.2 Å. The transmembrane helix was found to have an average immersion depth of 5.4 Å, indicating residues 41 and 42 are closest to the micelle centre. The resolution of paramagnetic relaxation rate enhancements from dissolved oxygen compares favourably to those from Ni (II), a hydrophilic paramagnetic species.

  3. Topology and immersion depth of an integral membrane protein by paramagnetic rates from dissolved oxygen

    International Nuclear Information System (INIS)

    Al-Abdul-Wahid, M. Sameer; Verardi, Raffaello; Veglia, Gianluigi; Prosser, R. Scott

    2011-01-01

    In studies of membrane proteins, knowledge of protein topology can provide useful insight into both structure and function. In this work, we present a solution NMR method for the measurement the tilt angle and average immersion depth of alpha helices in membrane proteins, from analysis of the paramagnetic relaxation rate enhancements arising from dissolved oxygen. No modification to the micelle or protein is necessary, and the topology of both transmembrane and amphipathic helices are readily determined. We apply this method to the measure the topology of a monomeric mutant of phospholamban (AFA-PLN), a 52-residue membrane protein containing both an amphipathic and a transmembrane alpha helix. In dodecylphosphocholine micelles, the amphipathic helix of AFA-PLN was found to have a tilt angle of 87° ± 1° and an average immersion depth of 13.2 Å. The transmembrane helix was found to have an average immersion depth of 5.4 Å, indicating residues 41 and 42 are closest to the micelle centre. The resolution of paramagnetic relaxation rate enhancements from dissolved oxygen compares favourably to those from Ni (II), a hydrophilic paramagnetic species.

  4. Neutrophil glycoprotein Mo1 is an integral membrane protein of plasma membranes and specific granules

    International Nuclear Information System (INIS)

    Stevenson, K.B.; Nauseef, W.M.; Clark, R.A.

    1987-01-01

    The glucoprotein Mo1 has previously been demonstrated to be on the cell surface and in the specific granule fraction of neutrophils and to be translocated to the cell surface during degranulation. It is not known, however, whether Mo1 is an integral membrane protein or a soluble, intragranular constituent loosely associated with the specific granule membrane. Purified neutrophils were disrupted by nitrogen cavitation and separated on Percoll density gradients into four fractions enriched for azurophilic granules, specific granules, plasma membrane, and cytosol, respectively. The glycoproteins in these fractions were labeled with 3 H-borohydride reduction, extracted with Triton X-114, and immunoprecipitated with 60.3, an anti-Mo1 monoclonal antibody. Mo1 was detected only in the specific granule and plasma membrane fractions and partitioned exclusively into the detergent-rich fraction consistent with Mo1 being an integral membrane protein. In addition, treatment of specific granule membranes with a high salt, high urea buffer to remove adsorbed or peripheral proteins failed to dissociate Mo1. These data support the hypothesis that Mo1 is an integral membrane protein of plasma and specific granule membranes in human neutrophils

  5. Specific ion effects on membrane potential and the permselectivity of ion exchange membranes.

    Science.gov (United States)

    Geise, Geoffrey M; Cassady, Harrison J; Paul, Donald R; Logan, Bruce E; Hickner, Michael A

    2014-10-21

    Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The charge density and polarizability

  6. Specific ion effects on membrane potential and the permselectivity of ion exchange membranes

    KAUST Repository

    Geise, Geoffrey M.

    2014-08-26

    © the Partner Organisations 2014. Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The

  7. Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

    Science.gov (United States)

    Hoey, J.; McCormick, M. I.; Hoey, A. S.

    2007-09-01

    The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5-39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output.

  8. Polymeric membranes modulate human keratinocyte differentiation in specific epidermal layers.

    Science.gov (United States)

    Salerno, Simona; Morelli, Sabrina; Giordano, Francesca; Gordano, Amalia; Bartolo, Loredana De

    2016-10-01

    In vitro models of human bioengineered skin substitutes are an alternative to animal experimentation for testing the effects and toxicity of drugs, cosmetics and pollutants. For the first time specific and distinct human epidermal strata were engineered by using membranes and keratinocytes. To this purpose, biodegradable membranes of chitosan (CHT), polycaprolactone (PCL) and a polymeric blend of CHT-PCL were prepared by phase-inversion technique and characterized in order to evaluate their morphological, physico-chemical and mechanical properties. The capability of membranes to modulate keratinocyte differentiation inducing specific interactions in epidermal membrane systems was investigated. The overall results demonstrated that the membrane properties strongly influence the cell morpho-functional behaviour of human keratinocytes, modulating their terminal differentiation, with the creation of specific epidermal strata or a fully proliferative epidermal multilayer system. In particular, human keratinocytes adhered on CHT and CHT-PCL membranes, forming the structure of the epidermal top layers, such as the corneum and granulosum strata, characterized by withdrawal or reduction from the cell cycle and cell proliferation. On the PCL membrane, keratinocytes developed an epidermal basal lamina, with high proliferating cells that stratified and migrated over time to form a complete differentiating epidermal multilayer system. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Specific ion effects on membrane potential and the permselectivity of ion exchange membranes

    KAUST Repository

    Geise, Geoffrey M.; Cassady, Harrison J.; Paul, Donald R.; Logan, Bruce E.; Hickner, Michael A.

    2014-01-01

    -ions also appeared to influence permselectivity leading to ion-specific effects; co-ions that are charge dense and have low polarizability tended to result in high membrane permselectivity. This journal is

  10. Option-4 algorithm for Florida pocket depth probe: reduction in the variance of site-specific probeable crevice depth measurements.

    Science.gov (United States)

    Breen, H J; Rogers, P; Johnson, N W; Slaney, R

    1999-08-01

    Clinical periodontal measurement is plagued by many sources of error which result in aberrant values (outliers). This study sets out to compare probeable crevice depth measurements (PCD) selected by the option-4 algorithm against those recorded with a conventional double-pass method and to quantify any reduction in site-specific PCD variances. A single clinician recorded full-mouth PCD at 1 visit in 32 subjects (mean age 45.5 years) with moderately advanced chronic adult periodontitis. PCD was recorded over 2 passes at 6 sites per tooth with the Florida Pocket Depth Probes, a 3rd generation probe. The option-4 algorithm compared the 1st pass site-specific PCD value (PCD1) to the 2nd pass site-specific PCD value (PCD2) and, if the difference between these values was >1.00 mm, allowed the recording of a maximum of 2 further measurements (3rd and 4th pass measurements PCD3 and PCD4): 4 site-specific measure-meets were considered to be the maximum subject and tissue tolerance. The algorithm selected the 1st 2 measurements whose difference was difference Y) (Y=[(A-B)/A]X 100) and a 75% reduction in the median site-specific variance of PCD1/PCD2.

  11. Substrate specificity within a family of outer membrane carboxylate channels.

    Directory of Open Access Journals (Sweden)

    Elif Eren

    2012-01-01

    Full Text Available Many Gram-negative bacteria, including human pathogens such as Pseudomonas aeruginosa, do not have large-channel porins. This results in an outer membrane (OM that is highly impermeable to small polar molecules, making the bacteria intrinsically resistant towards many antibiotics. In such microorganisms, the majority of small molecules are taken up by members of the OprD outer membrane protein family. Here we show that OprD channels require a carboxyl group in the substrate for efficient transport, and based on this we have renamed the family Occ, for outer membrane carboxylate channels. We further show that Occ channels can be divided into two subfamilies, based on their very different substrate specificities. Our results rationalize how certain bacteria can efficiently take up a variety of substrates under nutrient-poor conditions without compromising membrane permeability. In addition, they explain how channel inactivation in response to antibiotics can cause resistance but does not lead to decreased fitness.

  12. Prostate-specific membrane antigen and its truncated form PSM'

    Czech Academy of Sciences Publication Activity Database

    Mlčochová, Petra; Bařinka, Cyril; Tykvart, Jan; Šácha, Pavel; Konvalinka, Jan

    2009-01-01

    Roč. 69, č. 5 (2009), s. 471-479 ISSN 0270-4137 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : prostate specific membrane antigen * glutamate carboxypeptidase II * prostate cancer Subject RIV: CE - Biochemistry Impact factor: 3.081, year: 2009

  13. Specific interaction of postsynaptic densities with membrane rafts isolated from synaptic plasma membranes.

    Science.gov (United States)

    Liu, Qian; Yao, Wei-Dong; Suzuki, Tatsuo

    2013-06-01

    Postsynaptic membrane rafts are believed to play important roles in synaptic signaling, plasticity, and maintenance. We recently demonstrated the presence, at the electron microscopic level, of complexes consisting of membrane rafts and postsynaptic densities (PSDs) in detergent-resistant membranes (DRMs) prepared from synaptic plasma membranes (SPMs) ( Suzuki et al., 2011 , J Neurochem, 119, 64-77). To further explore these complexes, here we investigated the nature of the binding between purified SPM-DRMs and PSDs in vitro. In binding experiments, we used SPM-DRMs prepared after treating SPMs with n-octyl-β-d-glucoside, because at concentrations of 1.0% or higher it completely separates SPM-DRMs and PSDs, providing substantially PSD-free unique SPM-DRMs as well as DRM-free PSDs. PSD binding to PSD-free DRMs was identified by mass spectrometry, Western blotting, and electron microscopy. PSD proteins were not incorporated into SPMs, and significantly less PSD proteins were incorporated into DRMs prepared from liver membranes, providing in vitro evidence that binding of PSDs to DRMs is specific and suggestion of the presence of specific interacting molecules. These specific interactions may have important roles in synaptic development, function, and plasticity in vivo. In addition, the binding system we developed may be a good tool to search for binding molecules and binding mechanisms between PSDs and rafts.

  14. In-Depth Analysis of Citrulline Specific CD4 T-Cells in Rheumatoid Arthritis

    Science.gov (United States)

    2017-01-01

    AWARD NUMBER: W81XWH-15-1-0004 TITLE: In-Depth Analysis of Citrulline-Specific CD4 T - Cells in Rheumatoid Arthritis PRINCIPAL INVESTIGATOR...2016 4. TITLE AND SUBTITLE In-Depth Analysis of Citrulline-Specific CD4 T Cells in Rheumatoid Arthritis 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH...NOTES 14. ABSTRACT The goal of this project is to test the hypothesis that cit-specific CD4 T cells present in rheumatoid arthritis (RA) patients

  15. Aromatic Side Chain Water-to-Lipid Transfer Free Energies Show a Depth Dependence across the Membrane Normal.

    Science.gov (United States)

    McDonald, Sarah K; Fleming, Karen G

    2016-06-29

    Quantitating and understanding the physical forces responsible for the interactions of biomolecules are fundamental to the biological sciences. This is especially challenging for membrane proteins because they are embedded within cellular bilayers that provide a unique medium in which hydrophobic sequences must fold. Knowledge of the energetics of protein-lipid interactions is thus vital to understand cellular processes involving membrane proteins. Here we used a host-guest mutational strategy to calculate the Gibbs free energy changes of water-to-lipid transfer for the aromatic side chains Trp, Tyr, and Phe as a function of depth in the membrane. This work reveals an energetic gradient in the transfer free energies for Trp and Tyr, where transfer was most favorable to the membrane interfacial region and comparatively less favorable into the bilayer center. The transfer energetics follows the concentration gradient of polar atoms across the bilayer normal that naturally occurs in biological membranes. Additional measurements revealed nearest-neighbor coupling in the data set are influenced by a network of aromatic side chains in the host protein. Taken together, these results show that aromatic side chains contribute significantly to membrane protein stability through either aromatic-aromatic interactions or placement at the membrane interface.

  16. Determining the depth of certain gravity sources without a priori specification of their structural index

    Science.gov (United States)

    Zhou, Shuai; Huang, Danian

    2015-11-01

    We have developed a new method for the interpretation of gravity tensor data based on the generalized Tilt-depth method. Cooper (2011, 2012) extended the magnetic Tilt-depth method to gravity data. We take the gradient-ratio method of Cooper (2011, 2012) and modify it so that the source type does not need to be specified a priori. We develop the new method by generalizing the Tilt-depth method for depth estimation for different types of source bodies. The new technique uses only the three vertical tensor components of the full gravity tensor data observed or calculated at different height plane to estimate the depth of the buried bodies without a priori specification of their structural index. For severely noise-corrupted data, our method utilizes different upward continuation height data, which can effectively reduce the influence of noise. Theoretical simulations of the gravity source model with and without noise illustrate the ability of the method to provide source depth information. Additionally, the simulations demonstrate that the new method is simple, computationally fast and accurate. Finally, we apply the method using the gravity data acquired over the Humble Salt Dome in the USA as an example. The results show a good correspondence to the previous drilling and seismic interpretation results.

  17. In-Depth Analysis of Citrulline-Specific CD4 T-Cells in Rheumatoid Arthritis

    Science.gov (United States)

    2016-01-01

    be used to identify and characterize CD4+T cells specific for influenza A, West Nile, Yellow fever , Dengue and Japanese Encephalitis viruses. The...four difference species of Flavivirus using the TGEM approach. These will include: Yellow Fever Virus, West Nile Virus, Dengue Virus and Japanese...1 AWARD NUMBER: W81XWH-15-1-0004 TITLE: In-Depth Analysis of Citrulline-Specific CD4 T-Cells in Rheumatoid Arthritis PRINCIPAL INVESTIGATOR

  18. Mesophotic coral depth acclimatization is a function of host-specific symbiont physiology

    KAUST Repository

    Ziegler, Maren

    2015-02-06

    Mesophotic coral ecosystems receive increasing attention owing to their potential as deep coral refuges in times of global environmental change. Here, the mechanisms of coral holobiont photoacclimatization over a 60 m depth gradient in the central Red Sea were examined for the four coral genera Porites, Leptoseris, Pachyseris, and Podabacia. General acclimatization strategies were common to all host-symbiont combinations, e.g., Symbiodinium cell densities and photoprotective (PP) to light-harvesting pigment ratios both significantly decreased with water depth. Porites harbored Symbiodinium type C15 over the whole 60 m depth range, while Pachyseris and Podabacia had limited vertical distributions and hosted mainly Symbiodinium type C1. Symbiodinium type C15 had generally higher xanthophyll de-epoxidation rates and lower maximum quantum yields than C1, and also exhibited a strong photoacclimatory signal over depth that relates to the large distribution range of Porites. Interestingly, the coral host had an effect on Symbiodinium pigment composition. When comparing Symbiodinium type C1 in Podabacia and Pachyseris, the ß-carotene chl a−1, the peridinin chl a−1, and diadinoxanthin chl a−1 ratios were significantly different between host species. Our data support a view that depth acclimatization of corals in the mesophotics is facilitated by Symbiodinium physiology, which in turn is host-specific.

  19. Mesophotic coral depth acclimatization is a function of host-specific symbiont physiology

    KAUST Repository

    Ziegler, Maren; Roder, Cornelia; Bü chel, Claudia; Voolstra, Christian R.

    2015-01-01

    Mesophotic coral ecosystems receive increasing attention owing to their potential as deep coral refuges in times of global environmental change. Here, the mechanisms of coral holobiont photoacclimatization over a 60 m depth gradient in the central Red Sea were examined for the four coral genera Porites, Leptoseris, Pachyseris, and Podabacia. General acclimatization strategies were common to all host-symbiont combinations, e.g., Symbiodinium cell densities and photoprotective (PP) to light-harvesting pigment ratios both significantly decreased with water depth. Porites harbored Symbiodinium type C15 over the whole 60 m depth range, while Pachyseris and Podabacia had limited vertical distributions and hosted mainly Symbiodinium type C1. Symbiodinium type C15 had generally higher xanthophyll de-epoxidation rates and lower maximum quantum yields than C1, and also exhibited a strong photoacclimatory signal over depth that relates to the large distribution range of Porites. Interestingly, the coral host had an effect on Symbiodinium pigment composition. When comparing Symbiodinium type C1 in Podabacia and Pachyseris, the ß-carotene chl a−1, the peridinin chl a−1, and diadinoxanthin chl a−1 ratios were significantly different between host species. Our data support a view that depth acclimatization of corals in the mesophotics is facilitated by Symbiodinium physiology, which in turn is host-specific.

  20. Specificity of Plasma Membrane Targeting by the Rous Sarcoma Virus Gag Protein

    OpenAIRE

    Scheifele, Lisa Z.; Rhoads, Jonathan D.; Parent, Leslie J.

    2003-01-01

    Budding of C-type retroviruses begins when the viral Gag polyprotein is directed to the plasma membrane by an N-terminal membrane-binding (M) domain. While dispersed basic amino acids within the M domain are critical for stable membrane association and consequent particle assembly, additional residues or motifs may be required for specific plasma membrane targeting and binding. We have identified an assembly-defective Rous sarcoma virus (RSV) Gag mutant that retains significant membrane affin...

  1. Molecular organization in bacterial cell membranes. Specific labelling and topological distribution of glycoproteins and proteins in Streptomyces albus membranes

    Energy Technology Data Exchange (ETDEWEB)

    Larraga, V; Munoz, E [Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Instituto de Biologia Celular

    1975-05-01

    The paper reports about an investigation into the question of the specific labelling and topological distribution of glycoproteins and proteins in Streptomyces albus membranes. The method of sample preparation is described: Tritium labelling of glycoproteins in protoplasts and membranes, iodination of proteins, trypsin treatment and polyacrylamide gel electrophoresis. The findings suggest an asymmetrical distribution of the glycoproteins in membranes and a weak accessibility to iodine label. A structural model of the plasma membranes of Streptomyces albus is proposed similar to the general 'fluid mosaic' model of Singer and Nicholson.

  2. Preliminary level 2 specification for the nested, fixed-depth sampling system

    International Nuclear Information System (INIS)

    BOGER, R.M.

    1999-01-01

    This preliminary Level 2 Component Specification establishes the performance, design, development, and test requirements for the in-tank sampling system which will support the BNFL contract in the final disposal of Hanford's High Level Wastes (HLW) and Low Activity Wastes (LAW). The PHMC will provide Low Activity Wastes (LAW) tank wastes for final treatment by BNFL from double-shell feed tanks. Concerns about the inability of the baseline ''grab'' sampling to provide large volume samples within time constraints has led to the development of a nested, fixed-depth sampling system. This sampling system will provide large volume? representative samples without the environmental, radiation exposure, and sample volume Impacts of the current base-line ''grab'' sampling method. This preliminary Level 2 Component Specification is not a general specification for tank sampling, but is based on a ''record of decision'', AGA (HNF-SD-TWR-AGA-001 ), the System Specification for the Double Shell Tank System (HNF-SD-WM-TRD-O07), and the BNFL privatization contract

  3. Chironomid-based water depth reconstructions: an independent evaluation of site-specific and local inference models

    NARCIS (Netherlands)

    Engels, S.; Cwynar, L.C.; Rees, A.B.H.; Shuman, B.N.

    2012-01-01

    Water depth is an important environmental variable that explains a significant portion of the variation in the chironomid fauna of shallow lakes. We developed site-specific and local chironomid water-depth inference models using 26 and 104 surface-sediment samples, respectively, from seven

  4. Characterization of specific membrane fatty acids as chemotaxonomic markers for sulfate-reducing bacteria involved in anaerobic oxidation of methane

    DEFF Research Database (Denmark)

    Elvert, M.; Boetius, A.; Knittel, K.

    2003-01-01

    Membrane fatty acids were extracted from a sediment core above marine gas hydrates at Hydrate Ridge, NE Pacific. Anaerobic sediments from this environment are characterized by high sulfate reduction rates driven by the anaerobic oxidation of methane (AOM). The assimilation of methane carbon......-reducing bacteria (SRB) of the Desulfosarcina/Desulfococcus group, which are present in the aggregates of AOM consortia in extremely high numbers, these specific fatty acids appear to provide a phenotypic fingerprint indicative for SRB of this group. Correlating depth profiles of specific fatty acid content...

  5. Prostate Specific Membrane Antigen (PSMA) Targeted Bio-orthogonal Therapy for Metastatic Prostate Cancer

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-16-1-0595 TITLE: Prostate-Specific Membrane Antigen (PSMA) Targeted Bio -orthogonal Therapy for Metastatic Prostate Cancer...Sep 2016 - 14 Sep 2017 4. TITLE AND SUBTITLE Prostate-Specific Membrane Antigen (PSMA) Targeted Bio -orthogonal Therapy for Metastatic Prostate

  6. Sterol-specific membrane interactions with the toxins from ...

    African Journals Online (AJOL)

    The lipophilic toxins from Karlodinium micrum, KmTX, have negative effects on several co-occurring phytoplankton species, yet appear to have no effect on K. micrum itself. One of these compounds, KmTX2, has differing toxicity towards eukaryotic membranes with differing sterol compositions (vertebrate > fungal ...

  7. Endogenous glycosphingolipid acceptor specificity of sialosyltransferase systems in intact golgi membranes, synaptosomes, and synaptic plasma membranes from rat brain

    International Nuclear Information System (INIS)

    Durrie, R.; Saito, M.; Rosenberg, A.

    1988-01-01

    Preparations highly enriched in Golgi complex membranes, synaptosomes, and synaptic plasma membranes (SPM) by marker enzyme analysis and electron microscopic morphology were made from the brains of 28-day-old rats. These were incubated with cytidine 5'-monophosphate-N-acetyl[ 14 C]neuraminic acid (CMP-NeuAc) in a physiologic buffer, without detergents. Glycolipid sialosyltransferase activities (SATs) were measured by analyzing incorporation of radiolabeled NeuAc into endogenous membrane gangliosides. Golgi SAT was diversified in producing all the various molecular species of labeled gangliosides. Synaptosomal SAT exhibited a lower activity, but it was highly specific in its labeling pattern, with a marked preference for labeling NeuAcα2 → 8NeuAcα2 → 3Galβ1 → 4Glcβ1 → 1Cer (GD3 ganglioside). SPM prepared from the synaptosomes retained the GD3-related SAT (or SAT-2), and the total specific activity increased, which suggests that the location of the synaptosomal activity is in the SPM. These results indicate that SAT activity in Golgi membranes differs from that in synaptosomes with regard to endogenous acceptor substrate specificity and SAT activity of synaptosomes should be located in the synaptosomal plasma membrane. This SAT could function as an ectoenzyme in concert with ecto-sialidase to modulate the GD3 and other ganglioside population in situ at the SPM of the central nervous system

  8. Cancer Patient T Cells Genetically Targeted to Prostate-Specific Membrane Antigen Specifically Lyse Prostate Cancer Cells and Release Cytokines in Response to Prostate-Specific Membrane Antigen

    Directory of Open Access Journals (Sweden)

    Michael C. Gong

    1999-06-01

    Full Text Available The expression of immunoglobulin-based artificial receptors in normal T lymphocytes provides a means to target lymphocytes to cell surface antigens independently of major histocompatibility complex restriction. Such artificial receptors have been previously shown to confer antigen-specific tumoricidal properties in murine T cells. We constructed a novel ζ chain fusion receptor specific for prostate-specific membrane antigen (PSMA termed Pz-1. PSMA is a cell-surface glycoprotein expressed on prostate cancer cells and the neovascular endothelium of multiple carcinomas. We show that primary T cells harvested from five of five patients with different stages of prostate cancer and transduced with the Pz-1 receptor readily lyse prostate cancer cells. Having established a culture system using fibroblasts that express PSMA, we next show that T cells expressing the Pz-1 receptor release cytokines in response to cell-bound PSMA. Furthermore, we show that the cytokine release is greatly augmented by B7.1-mediated costimulation. Thus, our findings support the feasibility of adoptive cell therapy by using genetically engineered T cells in prostate cancer patients and suggest that both CD4+ and CD8+ T lymphocyte functions can be synergistically targeted against tumor cells.

  9. LHRH-pituitary plasma membrane binding: the presence of specific binding sites in other tissues.

    Science.gov (United States)

    Marshall, J C; Shakespear, R A; Odell, W D

    1976-11-01

    Two specific binding sites for LHRH are present on plasma membranes prepared from rat and bovine anterior pituitary glands. One site is of high affinity (K = 2X108 1/MOL) and the second is of lower affinity (8-5X105 1/mol) and much greater capacity. Studies on membrane fractions prepared from other tissues showed the presence of a single specific site for LHRH. The kinetics and specificity of this site were similar to those of the lower affinity pituitary receptor. These results indicate that only pituitary membranes possess the higher affinity binding site and suggest that the low affinity site is not of physiological importance in the regulation of gonadotrophin secretion. After dissociation from membranes of non-pituitary tissues 125I-LHRH rebound to pituitary membrane preparations. Thus receptor binding per se does not result in degradation of LHRH and the function of these peripheral receptors remains obscure.

  10. Ionizable polyethers as specific metal ion carriers in liquid-liquid extraction and liquid membrane separations

    International Nuclear Information System (INIS)

    Walkowiak, W.; Charewicz, W.A.; Bartsch, R.A.; Ndip, G.M.

    1988-01-01

    Consideration is given to results of investigations into competitive extraction and penetration through a liquid membrane of alkali and alkaline earth cations from aqueous solutions by a series of lipophilic and ionizable acyclic polyethers of various molecular structure. It is shown that specificity and selectiviy of cation carriers in liquid-liquid extraction and liquid membrane separation depend on molecular structure of acyclic polyethers

  11. Specific membrane lipid composition is important for plasmodesmata function in Arabidopsis.

    Science.gov (United States)

    Grison, Magali S; Brocard, Lysiane; Fouillen, Laetitia; Nicolas, William; Wewer, Vera; Dörmann, Peter; Nacir, Houda; Benitez-Alfonso, Yoselin; Claverol, Stéphane; Germain, Véronique; Boutté, Yohann; Mongrand, Sébastien; Bayer, Emmanuelle M

    2015-04-01

    Plasmodesmata (PD) are nano-sized membrane-lined channels controlling intercellular communication in plants. Although progress has been made in identifying PD proteins, the role played by major membrane constituents, such as the lipids, in defining specialized membrane domains in PD remains unknown. Through a rigorous isolation of "native" PD membrane fractions and comparative mass spectrometry-based analysis, we demonstrate that lipids are laterally segregated along the plasma membrane (PM) at the PD cell-to-cell junction in Arabidopsis thaliana. Remarkably, our results show that PD membranes display enrichment in sterols and sphingolipids with very long chain saturated fatty acids when compared with the bulk of the PM. Intriguingly, this lipid profile is reminiscent of detergent-insoluble membrane microdomains, although our approach is valuably detergent-free. Modulation of the overall sterol composition of young dividing cells reversibly impaired the PD localization of the glycosylphosphatidylinositol-anchored proteins Plasmodesmata Callose Binding 1 and the β-1,3-glucanase PdBG2 and altered callose-mediated PD permeability. Altogether, this study not only provides a comprehensive analysis of the lipid constituents of PD but also identifies a role for sterols in modulating cell-to-cell connectivity, possibly by establishing and maintaining the positional specificity of callose-modifying glycosylphosphatidylinositol proteins at PD. Our work emphasizes the importance of lipids in defining PD membranes. © 2015 American Society of Plant Biologists. All rights reserved.

  12. Relationship between severe obesity and depth to the cricothyroid membrane in third-trimester non-labouring parturients: a prospective observational study.

    Science.gov (United States)

    Gadd, K; Wills, K; Harle, R; Terblanche, N

    2018-05-01

    Severely obese parturients have increased 'cannot intubate, cannot oxygenate' risk during Caesarean section under general anaesthesia. Front-of-neck access (FONA) at the cricothyroid membrane (CTM) is definitive management; however, attempted FONA can fail. Point-of-care ultrasonography may provide useful information about CTM depth to aid FONA in obesity. This study determined the difference in CTM depth between severely obese and non-obese parturients, utilising ultrasonography. In this prospective observational study, two anaesthetists performed airway ultrasonography on 15 severely obese (BMI >45 kg m -2 ) and 15 normal-weight (BMI ≤25 kg m -2 ) parturients in the third trimester, using the transverse and longitudinal planes, sniffing and extended head positions, and nil and firm transducer pressures. The primary outcome was CTM depth (millimetres) measured in the transverse plane with the head extended and nil transducer pressure. Secondary outcomes included CTM depth measurements using other factor configurations. Intra-class correlation coefficients assessed the inter-observer reliability. CTM depth measured in the transverse plane with head extended and nil transducer pressure was significantly greater in severely obese parturients, mean 18.0 mm (95% confidence interval 16.3-19.8), vs 10.6 mm (8.81-12.4) in non-obese (P<0.001); mean difference 7.4 mm (4.9-9.9; P<0.001). CTM depths were increased in the severely obese group regardless of scanning plane, head and neck position, or transducer pressure (all P<0.001). There was excellent inter-observer reliability. Cricothyroid membrane depth is significantly increased in severely obese vs normal-weight parturients independently of scanning plane, head and neck position, or transducer pressure. Copyright © 2018 British Journal of Anaesthesia. All rights reserved.

  13. Depth profile analysis of non-specific fluorescence and color of tooth tissues after peroxide bleaching.

    Science.gov (United States)

    Klukowska, Malgorzata; Götz, Hermann; White, Donald J; Zoladz, James; Schwarz, Björn-Olaf; Duschner, Heinz

    2013-02-01

    To examine laboratory changes of endogenous non-specific fluorescence and color throughout subsurface of tooth structures prior to and following peroxide bleaching. Extracted human teeth were cross sectioned and mounted on glass slides. Cross sections were examined for internal color (digital camera) and nonspecific fluorescence (microRaman spectroscopy) throughout the tooth structure at specified locations. Surfaces of sections were then saturation bleached for 70 hours with a gel containing 6% hydrogen peroxide. Cross sections were reexamined for color and non-specific fluorescence changes. Unbleached enamel, dentin-enamel junction and dentin exhibit different CIELab color and non-specific fluorescence properties. Bleaching of teeth produced significant changes in color of internal cross sections and substantial reductions of non-specific fluorescence levels within enamel dentin and DEJ. Enamel and dentin non-specific fluorescence were reduced to common values with bleaching with enamel and the DEJ showing larger reductions than dentin.

  14. In-Depth Analysis of Citrulline-Specific CD4 T-Cells in Rheumatoid Arthritis

    Science.gov (United States)

    2018-01-01

    player in the activation of lymphoid , myeloid and mast cells , indicating MALT1’s crucial role in innate and adaptive signaling. Therefore, MALT1 is...for RA (IFRA) Program Session 7: Adaptive immunity vs. innate immunity and mesenchymal functions in RA Genetics, T cell specificity and T cell ...Program Session 7: Adaptive immunity vs. innate immunity and mesenchymal functions in RA Genetics, T cell specificity and T cell regulation in RA

  15. In Depth Analysis of Citrulline Specific CD4 T Cells in Rheumatoid Arthritis

    Science.gov (United States)

    2018-01-01

    activation of lymphoid , myeloid and mast cells , indicating MALT1’s crucial role in innate and adaptive signaling. Therefore, MALT1 is regarded a...Session 7: Adaptive immunity vs. innate immunity and mesenchymal functions in RA Genetics, T cell specificity and T cell regulation in RA Jane Buckner...IFRA) Program Session 7: Adaptive immunity vs. innate immunity and mesenchymal functions in RA Genetics, T cell specificity and T cell regulation in

  16. Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin

    International Nuclear Information System (INIS)

    Hicks, G.R.; Rayle, D.L.; Jones, A.M.; Lomax, T.L.

    1989-01-01

    Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-[7- 3 H]IAA([ 3 H]N 3 IAA), in a manner similar to the accumulation of [ 3 H]IAA. The association of the [ 3 H]N 3 IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of [ 3 H]N 3 IAA to plasma membrane vesicles prior to exposure to UV light and detected by subsequent NaDodSO 4 /PAGE and fluorography. When the reaction temperature was lowered to -196 degree C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors

  17. Numbers, biomass and cultivable diversity of microbial populations relate to depth and borehole-specific conditions in groundwater from depths of 4-450 m in Olkiluoto, Finland.

    Science.gov (United States)

    Pedersen, Karsten; Arlinger, Johanna; Eriksson, Sara; Hallbeck, Anna; Hallbeck, Lotta; Johansson, Jessica

    2008-07-01

    Microbiology, chemistry and dissolved gas in groundwater from Olkiluoto, Finland, were analysed over 3 years; samples came from 16 shallow observation tubes and boreholes from depths of 3.9-16.2 m and 14 deep boreholes from depths of 35-742 m. The average total number of cells (TNC) was 3.9 x 10(5) cells per ml in the shallow groundwater and 5.7 x 10(4) cells per ml in the deep groundwater. There was a significant correlation between the amount of biomass, analysed as ATP concentration, and TNC. ATP concentration also correlated with the stacked output of anaerobic most probable number cultivations of nitrate-, iron-, manganese- and sulphate-reducing bacteria, and acetogenic bacteria and methanogens. The numbers and biomass varied at most by approximately three orders of magnitude between boreholes, and TNC and ATP were positively related to the concentration of dissolved organic carbon. Two depth zones were found where the numbers, biomass and diversity of the microbial populations peaked. Shallow groundwater down to a depth of 16.2 m on average contained more biomass and cultivable microorganisms than did deep groundwater, except in a zone at a depth of approximately 300 m where the average biomass and number of cultivable microorganisms approached those of shallow groundwater. Starting at a depth of approximately 300 m, there were steep gradients of decreasing sulphate and increasing methane concentrations with depth; together with the peaks in biomass and sulphide concentration at this depth, these suggest that anaerobic methane oxidation may be a significant process at depth in Olkiluoto.

  18. In-depth analysis of subclass-specific conformational preferences of IgG antibodies

    Directory of Open Access Journals (Sweden)

    Xinsheng Tian

    2015-01-01

    Full Text Available IgG subclass-specific differences in biological function and in vitro stability are often referred to variations in the conformational flexibility, while this flexibility has rarely been characterized. Here, small-angle X-ray scattering data from IgG1, IgG2 and IgG4 antibodies, which were designed with identical variable regions, were thoroughly analysed by the ensemble optimization method. The extended analysis of the optimized ensembles through shape clustering reveals distinct subclass-specific conformational preferences, which provide new insights for understanding the variations in physical/chemical stability and biological function of therapeutic antibodies. Importantly, the way that specific differences in the linker region correlate with the solution structure of intact antibodies is revealed, thereby visualizing future potential for the rational design of antibodies with designated physicochemical properties and tailored effector functions. In addition, this advanced computational approach is applicable to other flexible multi-domain systems and extends the potential for investigating flexibility in solutions of macromolecules by small-angle X-ray scattering.

  19. Myxoviruses do not induce non-specific alterations in membrane permeability early on in infection

    International Nuclear Information System (INIS)

    Foster, K.A.; Micklem, K.J.; Bogomolova, N.N.; Boriskin, Y.S.; Pasternak, C.A.

    1983-01-01

    The permeability characteristics of cells infected with myxoviruses have been studied by measuring the concentrative uptake of nutrients, the concentration of intracellular K + , and the maintenance of the Na + gradient across the plasma membrane. Cells either show no change at all (Sendai virus-infected BHK cells and measles virus-infected Vero cells) or they show a decreased ability to concentrate nutrients, while intracellular K + and the Na + gradient remain unchanged (Sendai and influenza virus-infected L-1210 cells, measles virus-infected lymphocytes and mumps virus-infected L-41 cells). In no case, therefore, was a change observed that resembles the non-specific increase in membrane permeability induced by haemolytic paramyxoviruses (35, 42) or the non-specific membrane leakiness postulated to take place in infected cells (8, 9). A preliminary account of some of these findings has been presented (39)

  20. Possible evidence that dehydroepiandrosterone sulfate (DHA-S) stimulates cervical ripening by a membrane-mediated process: Specific binding-sites in plasma membrane from human uterine cervix

    International Nuclear Information System (INIS)

    Ohno, T.; Imai, A.; Tamaya, T.

    1991-01-01

    Fetal adrenal steroid, dehydroepiandrosterone sulfate (DHA-S) is well known to promote cervical ripening in late pregnancy. The presence of sites specifically binding the DHA-S in plasma membrane was studied in human cervical fibroblasts prepared from pregnant uterus. The fibroblasts were incubated with 3 H DHA-S and then fractionated into plasma membranes, cytosol, nuclei, and other organella debris. The specific activity of 3H-count in the plasma membrane fraction was enriched ∼ 7-fold compared with the whole homogenate. When the isolated plasma membrane preparations from the fibroblasts were exposed to 3 H DHA-S, the binding showed saturation kinetics; an apparent equilibrium dissociation constant (Kd) of 12 nM, and the binding capacity (Bmax) of 1.25 pmol/mg protein. The present results suggest that DHA is bound to and recognized by components in plasma membrane, and may exert its action on cervical ripening through the membrane-mediated processes

  1. Rescuing Those Left Behind: Recovering and Characterizing Underdigested Membrane and Hydrophobic Proteins To Enhance Proteome Measurement Depth.

    Science.gov (United States)

    Giannone, Richard J; Wurch, Louie L; Podar, Mircea; Hettich, Robert L

    2015-08-04

    The marine archaeon Nanoarchaeum equitans is dependent on direct physical contact with its host, the hyperthermophile Ignicoccus hospitalis. As this interaction is thought to be membrane-associated, involving a myriad of membrane-anchored proteins, proteomic efforts to better characterize this difficult to analyze interface are paramount to uncovering the mechanism of their association. By extending multienzyme digestion strategies that use sample filtration to recover underdigested proteins for reprocessing/consecutive proteolytic digestion, we applied chymotrypsin to redigest the proteinaceous material left over after initial proteolysis with trypsin of sodium dodecyl sulfate (SDS)-extracted I. hospitalis-N. equitans proteins. Using this method, we show that proteins with increased hydrophobic character, including membrane proteins with multiple transmembrane helices, are enriched and recovered in the underdigested fraction. Chymotryptic reprocessing provided significant sequence coverage gains in both soluble and hydrophobic proteins alike, with the latter benefiting more so in terms of membrane protein representation. These gains were despite a large proportion of high-quality peptide spectra remaining unassigned in the underdigested fraction suggesting high levels of protein modification on these often surface-exposed proteins. Importantly, these gains were achieved without applying extensive fractionation strategies usually required for thorough characterization of membrane-associated proteins and were facilitated by the generation of a distinct, complementary set of peptides that aid in both the identification and quantitation of this important, under-represented class of proteins.

  2. In-depth analysis of subclass-specific conformational preferences of IgG antibodies

    DEFF Research Database (Denmark)

    Tian, Xinsheng; Vestergaard, Bente; Thorolfsson, Matthias

    2015-01-01

    IgG subclass-specific differences in biological function and in vitro stability are often referred to variations in the conformational flexibility, while this flexibility has rarely been characterized. Here, small-angle X-ray scattering data from IgG1, IgG2 and IgG4 antibodies, which were designe...... properties and tailored effector functions. In addition, this advanced computational approach is applicable to other flexible multi-domain systems and extends the potential for investigating flexibility in solutions of macromolecules by small-angle X-ray scattering....

  3. Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

    Science.gov (United States)

    Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

    2005-12-01

    Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate

  4. Neuron specific Rab4 effector GRASP-1 coordinates membrane specialization and maturation of recycling endosomes

    NARCIS (Netherlands)

    C.C. Hoogenraad (Casper); I. Popa (Ioana); K. Futai (Kensuke); E. Sanchez-Martinez (Emma); P. Wulf (Phebe); T. van Vlijmen (Thijs); B.R. Dortland (Bjorn); V. Oorschot (Viola); R. Govers (Robert); M. Monti (Maria); A.J.R. Heck (Albert); M. Sheng (Morgan); J. Klumperman (Judith); H. Rehmann (Holger); D. Jaarsma (Dick); L.C. Kapitein (Lukas); P. van der Sluijs

    2010-01-01

    textabstractThe endosomal pathway in neuronal dendrites is essential for membrane receptor trafficking and proper synaptic function and plasticity. However, the molecular mechanisms that organize specific endocytic trafficking routes are poorly understood. Here, we identify GRIP-associated protein-1

  5. Quantitative Analysis of Human Pluripotency and Neural Specification by In-Depth (PhosphoProteomic Profiling

    Directory of Open Access Journals (Sweden)

    Ilyas Singec

    2016-09-01

    Full Text Available Controlled differentiation of human embryonic stem cells (hESCs can be utilized for precise analysis of cell type identities during early development. We established a highly efficient neural induction strategy and an improved analytical platform, and determined proteomic and phosphoproteomic profiles of hESCs and their specified multipotent neural stem cell derivatives (hNSCs. This quantitative dataset (nearly 13,000 proteins and 60,000 phosphorylation sites provides unique molecular insights into pluripotency and neural lineage entry. Systems-level comparative analysis of proteins (e.g., transcription factors, epigenetic regulators, kinase families, phosphorylation sites, and numerous biological pathways allowed the identification of distinct signatures in pluripotent and multipotent cells. Furthermore, as predicted by the dataset, we functionally validated an autocrine/paracrine mechanism by demonstrating that the secreted protein midkine is a regulator of neural specification. This resource is freely available to the scientific community, including a searchable website, PluriProt.

  6. Free radical-mediated stimulation of tyrosine-specific protein kinase in rat liver plasma membrane

    International Nuclear Information System (INIS)

    Chan, T.M.; Tatoyan, A.; Cheng, E.; Shargill, N.S.; Pleta, M.

    1986-01-01

    Incorporation of 32 P from (γ- 32 P)-ATP into endogenous proteins of plasma membranes isolated from rat liver was significantly increased by several naphthoquinones including menadione. This apparent stimulation of membrane-associated protein kinase activity by these compounds was most striking (up to 6-7 fold) when the synthetic copolymers containing glutamate and tyrosine residues (4:1) was used as substrate. Since tyrosine residues are the only possible phosphate acceptor in the copolymers, the quinone-stimulated liver membrane protein kinase is most likely tyrosine specific. Although not required for protein kinase activity, dithiothreitol (DTT) was necessary for its stimulation by these quinonoid compounds. Hydrolysis of ATP was not significantly affected by quinones under the experimental conditions. Both menadione and vitamin k 5 increased phosphorylation of plasma membrane proteins of molecular weight 45 and 60 kd. The stimulatory effect of menadione on protein phosphorylation was prevented by the addition of superoxide dismutase. Dihydroxyfumerate, which spontaneously produces various radical species, and H 2 O 2 , also stimulated tyrosine-specific protein phosphorylation. DTT was also required for their full effect. It, therefore, appears that quinonone stimulation of tyrosine-specific protein phosphorylation is mediated by oxygen radicals

  7. Prediction of membrane transport proteins and their substrate specificities using primary sequence information.

    Directory of Open Access Journals (Sweden)

    Nitish K Mishra

    Full Text Available Membrane transport proteins (transporters move hydrophilic substrates across hydrophobic membranes and play vital roles in most cellular functions. Transporters represent a diverse group of proteins that differ in topology, energy coupling mechanism, and substrate specificity as well as sequence similarity. Among the functional annotations of transporters, information about their transporting substrates is especially important. The experimental identification and characterization of transporters is currently costly and time-consuming. The development of robust bioinformatics-based methods for the prediction of membrane transport proteins and their substrate specificities is therefore an important and urgent task.Support vector machine (SVM-based computational models, which comprehensively utilize integrative protein sequence features such as amino acid composition, dipeptide composition, physico-chemical composition, biochemical composition, and position-specific scoring matrices (PSSM, were developed to predict the substrate specificity of seven transporter classes: amino acid, anion, cation, electron, protein/mRNA, sugar, and other transporters. An additional model to differentiate transporters from non-transporters was also developed. Among the developed models, the biochemical composition and PSSM hybrid model outperformed other models and achieved an overall average prediction accuracy of 76.69% with a Mathews correlation coefficient (MCC of 0.49 and a receiver operating characteristic area under the curve (AUC of 0.833 on our main dataset. This model also achieved an overall average prediction accuracy of 78.88% and MCC of 0.41 on an independent dataset.Our analyses suggest that evolutionary information (i.e., the PSSM and the AAIndex are key features for the substrate specificity prediction of transport proteins. In comparison, similarity-based methods such as BLAST, PSI-BLAST, and hidden Markov models do not provide accurate predictions

  8. An acid phosphatase in the plasma membranes of human astrocytoma showing marked specificity toward phosphotyrosine protein.

    Science.gov (United States)

    Leis, J F; Kaplan, N O

    1982-11-01

    The plasma membrane from the human tumor astrocytoma contains an active acid phosphatase activity based on hydrolysis of p-nitrophenyl phosphate. Other acid phosphatase substrates--beta-glycerophosphate, O-phosphorylcholine, and 5'-AMP--are not hydrolyzed significantly. The phosphatase activity is tartrate insensitive and is stimulated by Triton X-100 and EDTA. Of the three known phosphoamino acids, only free O-phosphotyrosine is hydrolyzed by the membrane phosphatase activity. Other acid phosphatases tested from potato, wheat germ, milk, and bovine prostate did not show this degree of specificity. The plasma membrane activity also dephosphorylated phosphotyrosine histone at a much greater rate than did the other acid phosphatases. pH profiles for free O-phosphotyrosine and phosphotyrosine histone showed a shift toward physiological pH, indicating possible physiological significance. Phosphotyrosine histone dephosphorylation activity was nearly 10 times greater than that seen for phosphoserine histone dephosphorylation, and Km values were much lower for phosphotyrosine histone dephosphorylation (0.5 microM vs. 10 microM). Fluoride and zinc significantly inhibited phosphoserine histone dephosphorylation. Vanadate, on the other hand, was a potent inhibitor of phosphotyrosine histone dephosphorylation (50% inhibition at 0.5 microM) but not of phosphoserine histone. ATP stimulated phosphotyrosine histone dephosphorylation (160-250%) but inhibited phosphoserine histone dephosphorylation (95%). These results suggest the existence of a highly specific phosphotyrosine protein phosphatase activity associated with the plasma membrane of human astrocytoma.

  9. Life without a cell membrane: Challenging the specificity of bacterial endophytes within Bryopsis (Bryopsidales, Chlorophyta

    Directory of Open Access Journals (Sweden)

    Hollants Joke

    2011-11-01

    Full Text Available Abstract Background The siphonous green macroalga Bryopsis has some remarkable characteristics. Besides hosting a rich endophytic bacterial flora, Bryopsis also displays extraordinary wound repair and propagation mechanisms. This latter feature includes the formation of protoplasts which can survive in the absence of a cell membrane for several minutes before regenerating into new individuals. This transient 'life without a membrane' state, however, challenges the specificity of the endophytic bacterial communities present and raises the question whether these bacteria are generalists, which are repeatedly acquired from the environment, or if there is some specificity towards the Bryopsis host. Results To answer this question, we examined the temporal stability and the uniqueness of endobiotic bacterial communities within Bryopsis samples from the Mexican west coast after prolonged cultivation. DGGE analysis revealed that Bryopsis endophytic bacterial communities are rather stable and clearly distinct from the epiphytic and surrounding cultivation water bacterial communities. Although these endogenous communities consist of both facultative and obligate bacteria, results suggest that Bryopsis owns some intrinsic mechanisms to selectively maintain and/or attract specific bacteria after repeated wounding events in culture. Conclusions This suggests that Bryopsis algae seem to master transient stages of life without a cell membrane well as they harbor specific - and possibly ecological significant - endophytic bacteria.

  10. Discriminatory Role of Detergent-Resistant Membranes in the Dimerization and Endocytosis of Prostate-Specific Membrane Antigen

    Science.gov (United States)

    Schmidt, Sonja; Gericke, Birthe; Fracasso, Giulio; Ramarli, Dunia; Colombatti, Marco; Naim, Hassan Y.

    2013-01-01

    Prostate-specific membrane antigen (PSMA) is a type-II membrane glycoprotein that was initially identified in LNCaP cells. It is expressed at elevated levels in prostate cancer. In view of the correlation between the expression levels of PSMA and disease grade and stage, PSMA is considered to be one of the most promising biomarkers in the diagnosis and treatment of prostate cancer. In LNCaP cells PSMA undergoes internalization via clathrin-coated pits followed by accumulation in the endosomes. PSMA associates with different types of detergent-resistant membranes (DRMs) along the secretory pathway. Its mature form is mainly insoluble in Lubrol WX, but does not associate with Triton X-100-DRMs. To understand the mechanism of PSMA internalization we investigated its association during internalization with DRMs. For this purpose, internalization was induced by antibody cross-linking. We demonstrate at the biochemical and cell biological levels that: [i] exclusively homodimers of PSMA are associated with Lubrol WX-DRMs, [ii] antibody-induced cross-linking of PSMA molecules results in a time-dependent partitioning into another DRMs type, namely Triton X-100-DRMs, and [iii] concomitant with its association with Triton-X-100-DRMs internalization of PSMA occurs along tubulin filaments. In a previous work (Colombatti et al. (2009) PLoS One 4: e4608) we demonstrated that the small GTPases RAS and RAC1 and the MAPKs p38 and ERK1/2 are activated during antibody cross-linking. As downstream effects of this activation we observed a strong induction of NF-kB associated with an increased expression of IL-6 and CCL5 genes and that IL-6 and CCL5 enhanced the proliferative potential of LNCaP cells synergistically. These observations together with findings reported here hypothesize a fundamental role of DRMs during activation of PSMA as platforms for trafficking, endocytosis and signalling. Understanding these mechanisms constitutes an essential prerequisite for utilization of PSMA as

  11. Discriminatory Role of Detergent-Resistant Membranes in the Dimerization and Endocytosis of Prostate-Specific Membrane Antigen.

    Directory of Open Access Journals (Sweden)

    Sonja Schmidt

    Full Text Available Prostate-specific membrane antigen (PSMA is a type-II membrane glycoprotein that was initially identified in LNCaP cells. It is expressed at elevated levels in prostate cancer. In view of the correlation between the expression levels of PSMA and disease grade and stage, PSMA is considered to be one of the most promising biomarkers in the diagnosis and treatment of prostate cancer. In LNCaP cells PSMA undergoes internalization via clathrin-coated pits followed by accumulation in the endosomes. PSMA associates with different types of detergent-resistant membranes (DRMs along the secretory pathway. Its mature form is mainly insoluble in Lubrol WX, but does not associate with Triton X-100-DRMs. To understand the mechanism of PSMA internalization we investigated its association during internalization with DRMs. For this purpose, internalization was induced by antibody cross-linking. We demonstrate at the biochemical and cell biological levels that: [i] exclusively homodimers of PSMA are associated with Lubrol WX-DRMs, [ii] antibody-induced cross-linking of PSMA molecules results in a time-dependent partitioning into another DRMs type, namely Triton X-100-DRMs, and [iii] concomitant with its association with Triton-X-100-DRMs internalization of PSMA occurs along tubulin filaments. In a previous work (Colombatti et al. (2009 PLoS One 4: e4608 we demonstrated that the small GTPases RAS and RAC1 and the MAPKs p38 and ERK1/2 are activated during antibody cross-linking. As downstream effects of this activation we observed a strong induction of NF-kB associated with an increased expression of IL-6 and CCL5 genes and that IL-6 and CCL5 enhanced the proliferative potential of LNCaP cells synergistically. These observations together with findings reported here hypothesize a fundamental role of DRMs during activation of PSMA as platforms for trafficking, endocytosis and signalling. Understanding these mechanisms constitutes an essential prerequisite for

  12. Direct effects of ionizing radiation on integral membrane proteins. Noncovalent energy transfer requires specific interpeptide interactions

    International Nuclear Information System (INIS)

    Jhun, E.; Jhun, B.H.; Jones, L.R.; Jung, C.Y.

    1991-01-01

    The 12 transmembrane alpha helices (TMHs) of human erythrocyte glucose transporter were individually cut by pepsin digestion as membrane-bound 2.5-3.5-kDa peptide fragments. Radiation-induced chemical degradation of these fragments showed an average target size of 34 kDa. This is 10-12 x larger than the average size of an individual TMH, demonstrating that a significant energy transfer occurs among these TMHs in the absence of covalent linkage. Heating this TMH preparation at 100 degree C for 15 min reduced the target size to 5 kDa or less, suggesting that the noncovalent energy transfer requires specific helix-helix interactions. Purified phospholamban, a small (6-kDa) integral membrane protein containing a single TMH, formed a pentameric assembly in sodium dodecyl sulfate. The chemical degradation target size of this phospholamban pentamer was 5-6 kDa, illustrating that not all integral membrane protein assemblies permit intersubunit energy transfer. These findings together with other published observations suggest strongly that significant noncovalent energy transfer can occur within the tertiary and quaternary structure of membrane proteins and that as yet undefined proper molecular interactions are required for such covalent energy transfer. Our results with pepsin-digested glucose transporter also illustrate the importance of the interhelical interaction as a predominating force in maintaining the tertiary structure of a transmembrane protein

  13. Ascorbic acid prevents nonreceptor specific binding of [3H]-5-hydroxytryptamine to bovine cerebral cortex membranes

    International Nuclear Information System (INIS)

    Hamblin, M.W.; Adriaenssens, P.I.; Ariani, K.; Cawthon, R.M.; Stratford, C.A.; Tan, G.L.; Ciaranello, R.D.

    1987-01-01

    [ 3 H]-5-Hydroxytryptamine ([ 3 H]-5-HT) decomposes rapidly when exposed to air in solution at physiological pH if antioxidants are not present. The decomposition products appear to bind to two saturable sites on brain membranes (apparent Kd values = 1-2 and 100-1000 nM). This binding mimics ''specific'' ligand/receptor binding in that it is inhibited by 10 microM unlabeled 5-HT. This inhibition is not competitive, but rather is due to the prevention of [ 3 H]-5-HT breakdown by excess unlabeled 5-HT. Unlike genuine ligand/receptor binding, the binding of [ 3 H]-5-HT breakdown products is essentially irreversible and does not display a tissue distribution consistent with binding to authentic 5-HT receptors. [ 3 H]-5-HT decomposition can be eliminated by the inclusion of 0.05 to 5 mM ascorbic acid. At these concentrations ascorbic acid is not deleterious to reversible [ 3 H]-5-HT binding. When [ 3 H] 5-HT exposure to air occurs in the presence of brain membranes, the apparent antioxidant activity of brain membranes themselves affords protection against [ 3 H]-5-HT degradation equal to ascorbic acid. This protection is effective below final [ 3 H]-5-HT concentrations of 10 nM. Above 10 nM [ 3 H]-5-HT, addition of ascorbic acid or other antioxidants is necessary to avoid the occurrence of additional low affinity (apparent Kd = 15-2000 nM) binding sites that are specific but nonetheless irreversible. When care is taken to limit [ 3 H]-5-HT oxidation, the only reversible and saturable specific binding sites observed are of the 5-HT1 high affinity (Kd = 1-2 nM) type. Radioligand oxidation artifacts may be involved in previous reports of low affinity (Kd = 15-250 nM) [ 3 H]-5-HT binding sites in brain membrane preparations

  14. Engineering a prostate-specific membrane antigen-activated tumor endothelial cell prodrug for cancer therapy

    DEFF Research Database (Denmark)

    Denmeade, Samuel R; Mhaka, Annastasiah M; Rosen, D Marc

    2012-01-01

    adenosine triphosphatase (SERCA) pump, whose proper function is required by all cell types for viability. To achieve targeted inhibition, we took advantage of the unique expression of the carboxypeptidase prostate-specific membrane antigen (PSMA) by tumor endothelial cells within the microenvironment...... of solid tumors. We generated a prodrug, G202, consisting of a PSMA-specific peptide coupled to an analog of the potent SERCA pump inhibitor thapsigargin. G202 produced substantial tumor regression against a panel of human cancer xenografts in vivo at doses that were minimally toxic to the host...

  15. Electronic structure of Pt-Co cathode catalysts in membrane electrolyte assembly observed by X-ray absorption fine structure spectroscopy with different probing depth

    International Nuclear Information System (INIS)

    Kobayashi, M.; Hidai, S.; Niwa, H.; Harada, Y.; Oshima, M.; Ofuchi, H.; Nakamori, Y.; Aoki, T.

    2010-01-01

    Electronic structures of Pt-Co cathode and Pt-Ru anode catalysts in membrane electrolyte assemblies (MEAs) for polymer electrolyte fuel cell have been investigated using X-ray absorption near edge structure (XANES) spectroscopy, and the changes of electronic structures accompanied with degradation have been observed by comparison between spectra obtained by fluorescence-yield (FY) and conversion-electron-yield (CEY) methods, probing depths of which are several hundreds μm and ∼100 nm, respectively. The Co K XANES spectra of the as-fabricated MEA show that the Co atoms in the cathode are metallic and oxidized Co ions exist at the interface between the cathode and electrolyte. The spectra of the long-time operated MEA suggest that the oxidation of Co makes progress with degradation of the cathode catalysts. In contrast to the Co K XANES spectra, the line shape of the Ru K XANES spectra is unchanged even after the long-time operation.

  16. Genetic regulation by amino acids of specific membrane protein biosynthesis in isolated rat hepatocytes

    International Nuclear Information System (INIS)

    Chiles, T.C.; Handlogten, M.E.; Kilberg, M.S.

    1986-01-01

    Rat Hepatocytes in primary culture were incubated in amino acid-free (AAF) medium or amino acid-supplemented (AAS) medium for 2-6 hr. The effect of amino acid starvation on the synthesis of specific membrane proteins was monitored by including 3 H-leucine during the incubation. A crude plasma membrane fraction was prepared and then analyzed by 2-D gel electrophoresis followed by fluorography. Amino acid deprivation caused an induction of the synthesis of 5 of the 30 proteins studied. The ratio (AAF/-AAS) of cpm incorporated into the remaining 25 proteins was 0.8 +/- 0.2, whereas the ratio for the 5 proteins that showed amino acid-dependent synthesis ranged from 1.5 to 2.5. The presence of 4 μM actinomycin in the AAF medium completely blocked the starvation-induced synthesis of the 5 proteins tested, but did not alter significantly the ratio of cpm incorporated into the other 25 proteins. Binding studies involving ConA suggested a plasma membrane location for the 5 proteins. The molecular weight values of the starvation-induced proteins are 70, 66, 66, 67, and 45kD. Surface-labelling of intact cells and preparation of antibodies against the 5 proteins will be used to establish the subcellular location and to describe the amino acid-dependent synthesis of each in more detail

  17. Evaluation of Cytochalasin B-Induced Membrane Vesicles Fusion Specificity with Target Cells

    Directory of Open Access Journals (Sweden)

    Marina Gomzikova

    2018-01-01

    Full Text Available Extracellular vesicles (EV represent a promising vector system for biomolecules and drug delivery due to their natural origin and participation in intercellular communication. As the quantity of EVs is limited, it was proposed to induce the release of membrane vesicles from the surface of human cells by treatment with cytochalasin B. Cytochalasin B-induced membrane vesicles (CIMVs were successfully tested as a vector for delivery of dye, nanoparticles, and a chemotherapeutic. However, it remained unclear whether CIMVs possess fusion specificity with target cells and thus might be used for more targeted delivery of therapeutics. To answer this question, CIMVs were obtained from human prostate cancer PC3 cells. The diameter of obtained CIMVs was 962,13 ± 140,6 nm. We found that there is no statistically significant preference in PC3 CIMVs fusion with target cells of the same type. According to our observations, the greatest impact on CIMVs entry into target cells is by the heterophilic interaction of CIMV membrane receptors with the surface proteins of target cells.

  18. Comparative analysis of monoclonal antibodies against prostate-specific membrane antigen (PSMA)

    Czech Academy of Sciences Publication Activity Database

    Tykvart, Jan; Navrátil, Václav; Sedlák, František; Corey, E.; Colombatti, M.; Fracasso, G.; Koukolík, F.; Bařinka, Cyril; Šácha, Pavel; Konvalinka, Jan

    2014-01-01

    Roč. 74, č. 16 (2014), s. 1674-1690 ISSN 0270-4137 R&D Projects: GA ČR GAP304/12/0847; GA MŠk LO1302; GA ČR GAP301/12/1513; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388963 ; RVO:86652036 Keywords : glutamate carboxypeptidase II * prostate -specific membrane antigen * folate hydrolase * NAALADase * Western blot * immunohistochemistry * ELISA * flow cytometry * surface plasmon resonance Subject RIV: CE - Biochemistry Impact factor: 3.565, year: 2014

  19. Fabrication of beta-PVDF membranes by track etching and specific functionalization of nano-pores

    International Nuclear Information System (INIS)

    Cuscito, O.

    2008-01-01

    Poly(vinylidene fluoride)(β-PVDF) nano-porous membranes were made by chemical revealing of tracks induced from swift heavy ions irradiation. Pore opening and radii can be varied in a controllable manner with the etching time. nano-pores size in nano-meter scale (from 12 nm to 50 nm) appears to be linearly dependent to the etching time. It was then necessary to adapt the characterization tools to these membranes. Consequently, we resorted to the use of structural analysis methods (Scanning Electron Microscopy, Small Angle Neutron Scattering) and developed evaluation methods of the membranes transport properties like gas permeation and ionic diffusion. Results obtained confirm the pores opening (break through) and the hydrophobicity of material, which we have modified with hydrophilic molecules. In this precise case, the grafting of acrylic acid was initiated by the radicals still remains after track-etching (called radio-grafting). This key result was obtained by a study of Electron Paramagnetic Resonance. The labelling of introduced chemical functionalities with fluorescent probes was a very effective mean to visualize very few amounts of molecules by confocal microscopy. The radio-grafting was found specifically localized inside etched tracks. The protocol offers the possibility to create a double functionality, the one localized inside the nano-pores and the other on the surface of membranes. The modification of radio-grafting parameters (the acrylic acid concentration, solvent nature, use of transfer agent) and the chemical properties of the nano-pore walls have a direct incidence on the transport properties. (author) [fr

  20. Flip-flop of phospholipids in proteoliposomes reconstituted from detergent extract of chloroplast membranes: kinetics and phospholipid specificity.

    Directory of Open Access Journals (Sweden)

    Archita Rajasekharan

    Full Text Available Eukaryotic cells are compartmentalized into distinct sub-cellular organelles by lipid bilayers, which are known to be involved in numerous cellular processes. The wide repertoire of lipids, synthesized in the biogenic membranes like the endoplasmic reticulum and bacterial cytoplasmic membranes are initially localized in the cytosolic leaflet and some of these lipids have to be translocated to the exoplasmic leaflet for membrane biogenesis and uniform growth. It is known that phospholipid (PL translocation in biogenic membranes is mediated by specific membrane proteins which occur in a rapid, bi-directional fashion without metabolic energy requirement and with no specificity to PL head group. A recent study reported the existence of biogenic membrane flippases in plants and that the mechanism of plant membrane biogenesis was similar to that found in animals. In this study, we demonstrate for the first time ATP independent and ATP dependent flippase activity in chloroplast membranes of plants. For this, we generated proteoliposomes from Triton X-100 extract of intact chloroplast, envelope membrane and thylakoid isolated from spinach leaves and assayed for flippase activity using fluorescent labeled phospholipids. Half-life time of flipping was found to be 6 ± 1 min. We also show that: (a intact chloroplast and envelope membrane reconstituted proteoliposomes can flip fluorescent labeled analogs of phosphatidylcholine in ATP independent manner, (b envelope membrane and thylakoid reconstituted proteoliposomes can flip phosphatidylglycerol in ATP dependent manner, (c Biogenic membrane ATP independent PC flipping activity is protein mediated and (d the kinetics of PC translocation gets affected differently upon treatment with protease and protein modifying reagents.

  1. Characterization of Prostate-Specific Membrane Antigen (PSMA) for Use in Therapeutic and Diagnostic Strategies Against Prostate Cancer

    National Research Council Canada - National Science Library

    O'Keefe, Denise

    2002-01-01

    Prostate-Specific Membrane Antigen (PSMA) appears to be an ideal prostate cancer marker and potential therapeutic target, however there have been reports of PSMA expression in non-prostatic tissues, including brain, kidney and liver...

  2. Development of a PET Prostate-Specific Membrane Antigen Imaging Agent: Preclinical Translation for Future Clinical Application

    Science.gov (United States)

    2017-10-01

    are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision unless so designated by...phase 0) application to the FDA by the end of the funding period. The small molecule imaging agents under study home to prostate specific membrane...funding period. The small molecule imaging agents under study home to prostate specific membrane antigen (PSMA) that is prevalent on a majority of

  3. Engineering a prostate-specific membrane antigen-activated tumor endothelial cell prodrug for cancer therapy.

    Science.gov (United States)

    Denmeade, Samuel R; Mhaka, Annastasiah M; Rosen, D Marc; Brennen, W Nathaniel; Dalrymple, Susan; Dach, Ingrid; Olesen, Claus; Gurel, Bora; Demarzo, Angelo M; Wilding, George; Carducci, Michael A; Dionne, Craig A; Møller, Jesper V; Nissen, Poul; Christensen, S Brøgger; Isaacs, John T

    2012-06-27

    Heterogeneous expression of drug target proteins within tumor sites is a major mechanism of resistance to anticancer therapies. We describe a strategy to selectively inhibit, within tumor sites, the function of a critical intracellular protein, the sarcoplasmic/endoplasmic reticulum calcium adenosine triphosphatase (SERCA) pump, whose proper function is required by all cell types for viability. To achieve targeted inhibition, we took advantage of the unique expression of the carboxypeptidase prostate-specific membrane antigen (PSMA) by tumor endothelial cells within the microenvironment of solid tumors. We generated a prodrug, G202, consisting of a PSMA-specific peptide coupled to an analog of the potent SERCA pump inhibitor thapsigargin. G202 produced substantial tumor regression against a panel of human cancer xenografts in vivo at doses that were minimally toxic to the host. On the basis of these data, a phase 1 dose-escalation clinical trial has been initiated with G202 in patients with advanced cancer.

  4. Snorc is a novel cartilage specific small membrane proteoglycan expressed in differentiating and articular chondrocytes

    DEFF Research Database (Denmark)

    Heinonen, J; Taipaleenmäki, H; Roering, P

    2011-01-01

    OBJECTIVE: Maintenance of chondrocyte phenotype is a major issue in prevention of degeneration and repair of articular cartilage. Although the critical pathways in chondrocyte maturation and homeostasis have been revealed, the in-depth understanding is deficient and novel modifying components...... subgroups. Cartilage specific expression was highest in proliferating and prehypertrophic zones during development, and in adult articular cartilage, expression was restricted to the uncalcified zone, including chondrocyte clusters in human osteoarthritic cartilage. Studies with experimental chondrogenesis...... chondrocytes and adult articular chondrocytes with possible functions associated with development and maintenance of chondrocyte phenotype....

  5. Specific membrane binding of factor VIII is mediated by O-phospho-L-serine, a moiety of phosphatidylserine.

    Science.gov (United States)

    Gilbert, G E; Drinkwater, D

    1993-09-21

    Phosphatidylserine, a negatively charged lipid, is exposed on the platelet membrane following cell stimulation, correlating with the expression of factor VIII receptors. We have explored the importance of the negative electrostatic potential of phosphatidylserine vs chemical moieties of phosphatidylserine for specific membrane binding of factor VIII. Fluorescein-labeled factor VIII bound to membranes containing 15% phosphatidic acid, a negatively charged phospholipid, with low affinity compared to phosphatidylserine-containing membranes. Binding was not specific as it was inhibited by other proteins in plasma. Factor VIII bound to membranes containing 10% phosphatidylserine in spite of a varying net charge provided by 0-15% stearylamine, a positively charged lipid. The soluble phosphatidylserine moiety, O-phospho-L-serine, inhibited factor VIII binding to phosphatidylserine-containing membranes with a Ki of 20 mM, but the stereoisomer, O-phospho-D-serine, was 5-fold less effective. Furthermore, binding of factor VIII to membranes containing synthetic phosphatidyl-D-serine was 5-fold less than binding to membranes containing phosphatidyl-L-serine. Membranes containing synthetic phosphatidyl-L-homoserine, differing from phosphatidylserine by a single methylene, supported high-affinity binding, but it was not specific as factor VIII was displaced by other plasma proteins. O-Phospho-L-serine also inhibited the binding of factor VIII to platelet-derived microparticles with a Ki of 20 mM, and the stereoisomer was 4-fold less effective. These results indicate that membrane binding of factor VIII is mediated by a stereoselective recognition O-phospho-L-serine of phosphatidylserine and that negative electrostatic potential is of lesser importance.

  6. Biochemical characterization of domain-specific glycoproteins of the rat hepatocyte plasma membrane

    International Nuclear Information System (INIS)

    Bartles, J.R.; Braiterman, L.T.; Hubbard, A.L.

    1985-01-01

    Seven integral proteins (CE 9, HA 21, HA 116, HA 16, HA 4, HA 201, and HA 301) were isolated from rat hepatocyte plasma membranes by immunoaffinity chromatography on monoclonal antibody-Sepharose. Six of the proteins (all but HA 16) exhibit domain-specific localizations (either bile canalicular or sinusoidal/lateral) about the hepatocyte surface. The authors identified three of these protein antigens as leucine aminopeptidase (HA 201), dipeptidyl peptidase IV (HA 301), and the asialoglycoprotein receptor (HA 116). They also developed 125 I-lectin blotting procedures that, when used in conjunction with chemical and glycosidase treatments, permitted a comparison of the types of oligosaccharides present on the seven proteins. All seven are sialoglycoproteins, based upon the effects of prior neuraminidase and periodate-aniline-cyanoborohydride treatments of blots on labeling by 125 I-wheat germ agglutinin. Depending upon the protein, they estimated the presence of 2-26 N-linked oligosaccharides/polypeptide chain from the Mr reductions accompanying chemical or enzymatic deglycosylation. Three of these mature plasma membrane proteins (HA 21, HA 116, and HA 4) have both high mannose-type and complex-type oligosaccharides on every copy of their polypeptide chains

  7. Comparative proteome analysis reveals pathogen specific outer membrane proteins of Leptospira.

    Science.gov (United States)

    Dhandapani, Gunasekaran; Sikha, Thoduvayil; Rana, Aarti; Brahma, Rahul; Akhter, Yusuf; Gopalakrishnan Madanan, Madathiparambil

    2018-04-10

    Proteomes of pathogenic Leptospira interrogans and L. borgpetersenii and the saprophytic L. biflexa were filtered through computational tools to identify Outer Membrane Proteins (OMPs) that satisfy the required biophysical parameters for their presence on the outer membrane. A total of 133, 130, and 144 OMPs were identified in L. interrogans, L. borgpetersenii, and L. biflexa, respectively, which forms approximately 4% of proteomes. A holistic analysis of transporting and pathogenic characteristics of OMPs together with Clusters of Orthologous Groups (COGs) among the OMPs and their distribution across 3 species was made and put forward a set of 21 candidate OMPs specific to pathogenic leptospires. It is also found that proteins homologous to the candidate OMPs were also present in other pathogenic species of leptospires. Six OMPs from L. interrogans and 2 from L. borgpetersenii observed to have similar COGs while those were not found in any intermediate or saprophytic forms. These OMPs appears to have role in infection and pathogenesis and useful for anti-leptospiral strategies. © 2018 Wiley Periodicals, Inc.

  8. Prostate specific membrane antigen- a target for imaging and therapy with radionuclides

    DEFF Research Database (Denmark)

    Bouchelouche, Kirsten; Choyke, Peter L; Capala, Jacek

    2010-01-01

    Prostate cancer continues to represent a major health problem, and yet there is no effective treatment available for advanced metastatic disease. Thus, there is an urgent need for the development of more effective treatment modalities that could improve the outcome. Because prostate specific...... membrane antigen (PSMA), a transmembrane protein, is expressed by virtually all prostate cancers, and its expression is further increased in poorly differentiated, metastatic, and hormone-refractory carcinomas, it is a very attractive target. Molecules targeting PSMA can be labelled with radionuclides...... to become both diagnostic and/or therapeutic agents. The use of PSMA binding agents, labelled with diagnostic and therapeutic radio-isotopes, opens up the potential for a new era of personalized management of metastatic prostate cancer....

  9. Immunological characterization of a basement membrane-specific chondroitin sulfate proteoglycan

    DEFF Research Database (Denmark)

    McCarthy, K J; Accavitti, M A; Couchman, J R

    1989-01-01

    with the proteoglycan preparation and four mAbs recognizing the core protein of a high-density, buoyant chondroitin sulfate proteoglycan were raised. Confirmation of antibody specificity was carried out by the preparation of affinity columns made from each of the mAbs. Chondroitin sulfate proteoglycans (CSPGs) were...... (Mr = 5-6 x 10(5)), with a core protein of Mr = approximately 1.5-1.6 x 10(5) and composed exclusively of chondroitin sulfate chains with an average Mr = 1.6-1.8 x 10(4). In addition, a CSPG was purified from adult rat kidney, whose core protein was also Mr = 1.6 x 10(5). The proteoglycan and its core...... sulfate proteoglycans, it therefore appears that at least one CSPG is a widespread basement membrane component....

  10. Inhibitory effect of membrane-specific drugs on liquid-holding recovery in U.V.-irradiated E. coli cells

    International Nuclear Information System (INIS)

    Yonei, S.

    1980-01-01

    Liquid-holding recovery (LHR), as been shown to be dependent on the polA + -dependent DNA repair pathways. The experiment described attempted to examine whether the membrane-specific drugs, procaine and chlorpromazine, can inhibit the LHR in U.V.-irradiated cells of E. coli B. Results show that cell membranes may influence DNA repair and ultimate survival of E. coli. (author)

  11. Galactosylated poly(ε-caprolactone) membrane promoted liver-specific functions of HepG2 cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan, E-mail: zhang_yan@ecust.edu.cn [The Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Yi [The Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen, Min; Zhou, Yan [The State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [The Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2014-08-01

    The lack of pendant functional groups on the PCL backbone has been a great challenge for surface bioactivation of poly(ε-caprolactone) (PCL). In the present study, covalently galactosylated PCL (GPCL) was developed through coupling between the amino-functionalized PCL (NPCL) and the lactobionic acid (LA) and its potential application in maintenance of physiological functions of HepG2 cells was further evaluated. The structure and properties of GPCL were explored by {sup 1}H NMR, FT-IR, GPC and DSC. Moreover, the incorporation of galactose ligands onto GPCL membranes not only promoted higher wettability, but also radically changed surface morphology in comparison with PCL and NPCL according to the contact angle measurement and atomic force microscopy. When HepG2 cells were seeded onto these membranes, the cells on GPCL membranes showed more pronounced cell adhesion and tended to form aggregates during the initial adhesion stage and then progressively grew into multi-layer structures compared to those without galactose ligands by the observation with fluorescence microscope and scanning electron microscopy. Furthermore, live–dead assay and functional tests demonstrated that HepG2 cells on GPCL membranes had superior viability and maintained better liver-specific functions. Collectively, GPCL has great potential for hepatic tissue engineering scaffolds. - Graphical abstract: The specific recognition between the galactose ligands on the galactosylated poly(ε-caprolactone) membrane and the ASGPR on the HepG2 cell surface. The galactosylated poly(ε-caprolactone) membranes improved the cell-matrix interaction. The galactosylated functionalized PCL scaffold is a potential candidate for liver tissue engineering. - Highlights: • The specific recognition between the galactose ligands on the galactosylated poly(ε-caprolactone) membrane and the ASGPR on the HepG2 cell surface. • The galactosylated poly(ε-caprolactone) membranes improved the cell-matrix interaction.

  12. Advanced generation anti-prostate specific membrane antigen designer T cells for prostate cancer immunotherapy.

    Science.gov (United States)

    Ma, Qiangzhong; Gomes, Erica M; Lo, Agnes Shuk-Yee; Junghans, Richard P

    2014-02-01

    Adoptive immunotherapy by infusion of designer T cells (dTc) engineered with chimeric antigen receptors (CARs) for tumoricidal activity represents a potentially highly specific modality for the treatment of cancer. In this study, 2nd generation (gen) anti-prostate specific membrane antigen (PSMA) dTc were developed for improving the efficacy of previously developed 1st gen dTc for prostate cancer immunotherapy. The 1st gen dTc are modified with chimeric immunoglobulin-T cell receptor (IgTCR) while the 2nd gen dTc are engineered with an immunoglobulin-CD28-T cell receptor (IgCD28TCR), which incorporates a CD28 costimulatory signal for optimal T cell activation. A 2nd gen anti-PSMA IgCD28TCR CAR was constructed by inserting the CD28 signal domain into the 1st gen CAR. 1st and 2nd gen anti-PSMA dTc were created by transducing human T cells with anti-PSMA CARs and their antitumor efficacy was compared for specific activation on PSMA-expressing tumor contact, cytotoxicity against PSMA-expressing tumor cells in vitro, and suppression of tumor growth in an animal model. The 2nd gen dTc can be optimally activated to secrete larger amounts of cytokines such as IL2 and IFNγ than 1st gen and to proliferate more vigorously on PSMA-expressing tumor contact. More importantly, the 2nd gen dTc preserve the PSMA-specific cytotoxicity in vitro and suppress tumor growth in animal models with significant higher potency. Our results demonstrate that 2nd gen anti-PSMA designer T cells exhibit superior antitumor functions versus 1st gen, providing a rationale for advancing this improved agent toward clinical application in prostate cancer immunotherapy. © 2013 Wiley Periodicals, Inc.

  13. Prostate-Specific Membrane Antigen Targeted Therapy of Prostate Cancer Using a DUPA-Paclitaxel Conjugate.

    Science.gov (United States)

    Lv, Qingzhi; Yang, Jincheng; Zhang, Ruoshi; Yang, Zimeng; Yang, Zhengtao; Wang, Yongjun; Xu, Youjun; He, Zhonggui

    2018-05-07

    Prostate cancer (PCa) is the most prevalent cancer among men in the United States and remains the second-leading cause of cancer mortality in men. Paclitaxel (PTX) is the first line chemotherapy for PCa treatment, but its therapeutic efficacy is greatly restricted by the nonspecific distribution in vivo. Prostate-specific membrane antigen (PSMA) is overexpressed on the surface of most PCa cells, and its expression level increases with cancer aggressiveness, while being present at low levels in normal cells. The high expression level of PSMA in PCa cells offers an opportunity for target delivery of nonspecific cytotoxic drugs to PCa cells, thus improving therapeutic efficacy and reducing toxicity. PSMA has high affinity for DUPA, a glutamate urea ligand. Herein, a novel DUPA-PTX conjugate is developed using DUPA as the targeting ligand to deliver PTX specifically for treatment of PSMA expressing PCa. The targeting ligand DUPA enhances the transport capability and selectivity of PTX to tumor cells via PSMA mediated endocytosis. Besides, DUPA is conjugated with PTX via a disulfide bond, which facilitates the rapid and differential drug release in tumor cells. The DUPA-PTX conjugate exhibits potent cytotoxicity in PSMA expressing cell lines and induces a complete cessation of tumor growth with no obvious toxicity. Our findings give new insight into the PSMA-targeted delivery of chemotherapeutics and provide an opportunity for the development of novel active targeting drug delivery systems for PCa therapy.

  14. Preparation of a high specific activity I-125 labeled styryl dye for leukocyte membrane labeling

    International Nuclear Information System (INIS)

    Lambert, C.; Mease, R.C.; Le, T.; Sabet, H.; Avren, L.I.; McAfee, J.G.

    1994-01-01

    The purpose of this work was to develop a high specific activity radioiodinated cell membrane probe for tracking lymphocytes in-vivo to replace the nucleus localizing, cytotoxic lipophilic chelates (In-111 oxine and Tc-99m HMPAO) currently used. Alkylation of parent dye 4-[2-[-N,N-didecylamino]phenyl]ethenyl pyridine with E-1-tributylstannyl-3-tosylpropene (prepared form E-1-tributylstannyl-1-propene-3-ol), gave a tributyltin precursor 1. Radiolabeled 3-[4-[2-[4-(N,N-didecylamino)phenyl]ethenyl]pyridino] E-[I-125]-1-iodopropene (2), was prepared from 1 using peracetic acid in acetonitrile/water. Labeling yields and specific activities achieved were 26% (∼2170 Ci/mmol), 40% (1220 Ci/mmol), and 55% (200 Ci/mmol) for nca, 0.4, and 2 nanomole carrier iodide runs respectively. Canine mixed leukocytes (0.5-1.0 x 10 8 cells) were labeled with 2 (67% and 42% yields for 200 Ci/mol and 1220 Ci/mmol preparations) and showed blood clearance similar to In 111 oxine. Radioiodinated styryl dye 2 appears to be a promising leukocyte labeling agent. Imaging studies with I-131 labeled 2 are in progress

  15. Advances in prostate-specific membrane antigen PET of prostate cancer.

    Science.gov (United States)

    Bouchelouche, Kirsten; Choyke, Peter L

    2018-05-01

    In recent years, a large number of reports have been published on prostate-specific membrane antigen (PSMA)/PET in prostate cancer (PCa). This review highlights advances in PSMA PET in PCa during the past year. PSMA PET/computed tomography (CT) is useful in detection of biochemical recurrence, especially at low prostate-specific antigen (PSA) values. The detection rate of PSMA PET is influenced by PSA level. For primary PCa, PSMA PET/CT shows promise for tumour localization in the prostate, especially in combination with multiparametric MRI (mpMRI). For primary staging, PSMA PET/CT can be used in intermediate and high-risk PCa. Intraoperative PSMA radioligand guidance seems promising for detection of malignant lymph nodes. While the use of PSMA PET/MRI in primary localized disease is limited to high and intermediate-risk patients and localized staging, in the recurrence setting, PET/MRI can be particularly helpful when the lesions are subtle. PSMA PET/CT is superior to choline PET/CT and other conventional imaging modalities. Molecular imaging with PSMA PET continues to pave the way for personalized medicine in PCa.However, large prospective clinical studies are still needed to fully evaluate the role of PSMA PET/CT and PET/MRI in the clinical workflow of PCa.

  16. Identification and characterization of a stage specific membrane protein involved in flagellar attachment in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Katherine Woods

    Full Text Available Flagellar attachment is a visibly striking morphological feature of African trypanosomes but little is known about the requirements for attachment at a molecular level. This study characterizes a previously undescribed membrane protein, FLA3, which plays an essential role in flagellar attachment in Trypanosoma brucei. FLA3 is heavily N-glycosylated, locates to the flagellar attachment zone and appears to be a bloodstream stage specific protein. Ablation of the FLA3 mRNA rapidly led to flagellar detachment and a concomitant failure of cytokinesis in the long slender bloodstream form but had no effect on the procyclic form. Flagellar detachment was obvious shortly after induction of the dsRNA and the newly synthesized flagellum was often completely detached after it emerged from the flagellar pocket. Within 12 h most cells possessed detached flagella alongside the existing attached flagellum. These results suggest that proteins involved in attachment are not shared between the new and old attachment zones. In other respects the detached flagella appear normal, they beat rapidly although directional motion was lost, and they possess an apparently normal axoneme and paraflagellar rod structure. The flagellar attachment zone appeared to be disrupted when FLA3 was depleted. Thus, while flagellar attachment is a constitutive feature of the life cycle of trypanosomes, attachment requires stage specific elements at the protein level.

  17. Relations among water levels, specific conductance, and depths of bedrock fractures in four road-salt-contaminated wells in Maine, 2007–9

    Science.gov (United States)

    Schalk, Charles W.; Stasulis, Nicholas W.

    2012-01-01

    Data on groundwater-level, specific conductance (a surrogate for chloride), and temperature were collected continuously from 2007 through 2009 at four bedrock wells known to be affected by road salts in an effort to determine the effects of road salting and fractures in bedrock that intersect the well at a depth below the casing on the presence of chloride in groundwater. Dissolved-oxygen data collected periodically also were used to make inferences about the interaction of fractures and groundwater flow. Borehole geophysical tools were used to determine the depths of fractures in each well that were actively contributing flow to the well, under both static and pumped conditions; sample- and measurement-depths were selected to correspond to the depths of these active fractures. Samples of water from the wells, collected at depths corresponding to active bedrock fractures, were analyzed for chloride concentration and specific conductance; from these analyses, a linear relation between chloride concentration and specific conductance was established, and continuous and periodic measurements of specific conductance were assumed to represent chloride concentration of the well water at the depth of measurement. To varying degrees, specific conductance increased in at least two of the wells during winter and spring thaws; the shallowest well, which also was closest to the road receiving salt treatment during the winter, exhibited the largest changes in specific conductance during thaws. Recharge events during summer months, long after application of road salt had ceased for the year, also produced increases in specific conductance in some of the wells, indicating that chloride which had accumulated or sequestered in the overburden was transported to the wells throughout the year. Geophysical data and periodic profiles of water quality along the length of each well’s borehole indicated that the greatest changes in water quality were associated with active fractures; in

  18. The peripheral binding of 14-3-3γ to membranes involves isoform-specific histidine residues.

    Directory of Open Access Journals (Sweden)

    Helene J Bustad

    Full Text Available Mammalian 14-3-3 protein scaffolds include seven conserved isoforms that bind numerous phosphorylated protein partners and regulate many cellular processes. Some 14-3-3-isoforms, notably γ, have elevated affinity for membranes, which might contribute to modulate the subcellular localization of the partners and substantiate the importance of investigating molecular mechanisms of membrane interaction. By applying surface plasmon resonance we here show that the binding to phospholipid bilayers is stimulated when 14-3-3γ is complexed with its partner, a peptide corresponding to the Ser19-phosphorylated N-terminal region of tyrosine hydroxylase. Moreover, membrane interaction is dependent on salts of kosmotropic ions, which also stabilize 14-3-3γ. Electrostatic analysis of available crystal structures of γ and of the non-membrane-binding ζ-isoform, complemented with molecular dynamics simulations, indicate that the electrostatic potential distribution of phosphopeptide-bound 14-3-3γ is optimal for interaction with the membrane through amphipathic helices at the N-terminal dimerization region. In addition, His158, and especially His195, both specific to 14-3-3γ and located at the convex lateral side, appeared to be pivotal for the ligand induced membrane interaction, as corroborated by site-directed mutagenesis. The participation of these histidine residues might be associated to their increased protonation upon membrane binding. Overall, these results reveal membrane-targeting motifs and give insights on mechanisms that furnish the 14-3-3γ scaffold with the capacity for tuned shuffling from soluble to membrane-bound states.

  19. Basement membrane-specific chondroitin sulfate proteoglycan is abnormally associated with the glomerular capillary basement membrane of diabetic rats

    DEFF Research Database (Denmark)

    McCarthy, K J; Abrahamson, D R; Bynum, K R

    1994-01-01

    exception being the normal glomerular capillary basement membrane (GBM), where it is absent. In the present study of mature kidneys we examined the distribution of BM-CSPG in streptozocin-induced diabetes mellitus in rats. We found BM-CSPG atypically associated with the GBM of diabetic animals as early as 1...... month after induction of diabetes mellitus. Immunoelectron microscopy (IEM) of affected capillary loops showed BM-CSPG present in the subendothelial matrix in areas of GBM thickening and absent in areas where the GBM appears to be of normal thickness. Moreover, the association of BM-CSPG with regions...... of the pericapillary GBM affects the morphology of the capillary endothelial cells within these areas, directly displacing the cell body from the GBM proper and causing loss of fenestrae. These new data on BM-CSPG distribution reflect abnormal glomerular extracellular matrix protein biosynthesis/turnover in diabetes...

  20. Assessment of Membrane Fluidity Fluctuations during Cellular Development Reveals Time and Cell Type Specificity

    KAUST Repository

    Noutsi, Bakiza Kamal; Gratton, Enrico; Chaieb, Saharoui

    2016-01-01

    Cell membrane is made up of a complex structure of lipids and proteins that diffuse laterally giving rise to what we call membrane fluidity. During cellular development, such as differentiation cell membranes undergo dramatic fluidity changes induced by proteins such as ARC and Cofilin among others. In this study we used the generalized polarization (GP) property of fluorescent probe Laurdan using two-photon microscopy to determine membrane fluidity as a function of time and for various cell lines. A low GP value corresponds to a higher fluidity and a higher GP value is associated with a more rigid membrane. Four different cell lines were monitored such as hN2, NIH3T3, HEK293 and L6 cells. Membrane fluidity was measured at 12h, 72h and 92 h. Our results show significant changes in membrane fluidity among all cell types at different time points. GP values tend to increase significantly within 92 h in hN2 cells and 72 h in NIH3T3 cells and only at 92 h in HEK293 cells. L6 showed a marked decrease in membrane fluidity at 72 h and starts to increase at 92 h. As expected, NIH3T3 cells have more rigid membrane at earlier time points. On the other hand, neurons tend to have the highest membrane fluidity at early time points emphasizing its correlation with plasticity and the need for this malleability during differentiation. This study sheds light on the involvement of membrane fluidity during neuronal differentiation and development of other cell lines.

  1. Assessment of Membrane Fluidity Fluctuations during Cellular Development Reveals Time and Cell Type Specificity

    KAUST Repository

    Noutsi, Bakiza Kamal

    2016-06-30

    Cell membrane is made up of a complex structure of lipids and proteins that diffuse laterally giving rise to what we call membrane fluidity. During cellular development, such as differentiation cell membranes undergo dramatic fluidity changes induced by proteins such as ARC and Cofilin among others. In this study we used the generalized polarization (GP) property of fluorescent probe Laurdan using two-photon microscopy to determine membrane fluidity as a function of time and for various cell lines. A low GP value corresponds to a higher fluidity and a higher GP value is associated with a more rigid membrane. Four different cell lines were monitored such as hN2, NIH3T3, HEK293 and L6 cells. Membrane fluidity was measured at 12h, 72h and 92 h. Our results show significant changes in membrane fluidity among all cell types at different time points. GP values tend to increase significantly within 92 h in hN2 cells and 72 h in NIH3T3 cells and only at 92 h in HEK293 cells. L6 showed a marked decrease in membrane fluidity at 72 h and starts to increase at 92 h. As expected, NIH3T3 cells have more rigid membrane at earlier time points. On the other hand, neurons tend to have the highest membrane fluidity at early time points emphasizing its correlation with plasticity and the need for this malleability during differentiation. This study sheds light on the involvement of membrane fluidity during neuronal differentiation and development of other cell lines.

  2. Prostate-specific membrane antigen-directed nanoparticle targeting for extreme nearfield ablation of prostate cancer cells.

    Science.gov (United States)

    Lee, Seung S; Roche, Philip Jr; Giannopoulos, Paresa N; Mitmaker, Elliot J; Tamilia, Michael; Paliouras, Miltiadis; Trifiro, Mark A

    2017-03-01

    Almost all biological therapeutic interventions cannot overcome neoplastic heterogeneity. Physical ablation therapy is immune to tumor heterogeneity, but nearby tissue damage is the limiting factor in delivering lethal doses. Multi-walled carbon nanotubes offer a number of unique properties: chemical stability, photonic properties including efficient light absorption, thermal conductivity, and extensive surface area availability for covalent chemical ligation. When combined together with a targeting moiety such as an antibody or small molecule, one can deliver highly localized temperature increases and cause extensive cellular damage. We have functionalized multi-walled carbon nanotubes by conjugating an antibody against prostate-specific membrane antigen. In our in vitro studies using prostate-specific membrane antigen-positive LNCaP prostate cancer cells, we have effectively demonstrated cell ablation of >80% with a single 30-s exposure to a 2.7-W, 532-nm laser for the first time without bulk heating. We also confirmed the specificity and selectivity of prostate-specific membrane antigen targeting by assessing prostate-specific membrane antigen-null PC3 cell lines under the same conditions (<10% cell ablation). This suggests that we can achieve an extreme nearfield cell ablation effect, thus restricting potential tissue damage when transferred to in vivo clinical applications. Developing this new platform will introduce novel approaches toward current therapeutic modalities and will usher in a new age of effective cancer treatment squarely addressing tumoral heterogeneity.

  3. Synergistic co-targeting of prostate-specific membrane antigen and androgen receptor in prostate cancer.

    Science.gov (United States)

    Murga, Jose D; Moorji, Sameer M; Han, Amy Q; Magargal, Wells W; DiPippo, Vincent A; Olson, William C

    2015-02-15

    Antibody-drug conjugates (ADCs) are an emerging class of cancer therapies that have demonstrated favorable activity both as single agents and as components of combination regimens. Phase 2 testing of an ADC targeting prostate-specific membrane antigen (PSMA) in advanced prostate cancer has shown antitumor activity. The present study examined PSMA ADC used in combination with potent antiandrogens (enzalutamide and abiraterone) and other compounds. Antiproliferative activity and expression of PSMA, prostate-specific antigen and androgen receptor were evaluated in the prostate cancer cell lines LNCaP and C4-2. Cells were tested for susceptibility to antiandrogens or other inhibitors, used alone and in combination with PSMA ADC. Potential drug synergy or antagonism was evaluated using the Bliss independence method. Enzalutamide and abiraterone demonstrated robust, statistically significant synergy when combined with PSMA ADC. Largely additive activity was observed between the antiandrogens and the individual components of the ADC (free drug and unmodified antibody). Rapamycin also synergized with PSMA ADC in certain settings. Synergy was linked in part to upregulation of PSMA expression. In androgen-dependent LNCaP cells, enzalutamide and abiraterone each inhibited proliferation, upregulated PSMA expression, and synergized with PSMA ADC. In androgen-independent C4-2 cells, enzalutamide and abiraterone showed no measurable antiproliferative activity on their own but increased PSMA expression and synergized with PSMA ADC nonetheless. PSMA expression increased progressively over 3 weeks with enzalutamide and returned to baseline levels 1 week after enzalutamide removal. The findings support exploration of clinical treatment regimens that combine potent antiandrogens and PSMA-targeted therapies for prostate cancer. © 2014 Wiley Periodicals, Inc.

  4. The Down regulated in Adenoma (dra) gene encodes an intestine-specific membrane sulfate transport protein.

    Science.gov (United States)

    Silberg, D G; Wang, W; Moseley, R H; Traber, P G

    1995-05-19

    A gene has been described, Down Regulated in Adenoma (dra), which is expressed in normal colon but is absent in the majority of colon adenomas and adenocarcinomas. However, the function of this protein is unknown. Because of sequence similarity to a recently cloned membrane sulfate transporter in rat liver, the transport function of Dra was examined. We established that dra encodes for a Na(+)-independent transporter for both sulfate and oxalate using microinjected Xenopus oocytes as an assay system. Sulfate transport was sensitive to the anion exchange inhibitor DIDS (4,4'-diisothiocyano-2,2' disulfonic acid stilbene). Using an RNase protection assay, we found that dra mRNA expression is limited to the small intestine and colon in mouse, therefore identifying Dra as an intestine-specific sulfate transporter. dra also had a unique pattern of expression during intestinal development. Northern blot analysis revealed a low level of expression in colon at birth with a marked increase in the first 2 postnatal weeks. In contrast, there was a lower, constant level of expression in small intestine in the postnatal period. Caco-2 cells, a colon carcinoma cell line that differentiates over time in culture, demonstrated a marked induction of dra mRNA as cells progressed from the preconfluent (undifferentiated) to the postconfluent (differentiated) state. These results show that Dra is an intestine-specific Na(+)-independent sulfate transporter that has differential expression during colonic development. This functional characterization provides the foundation for investigation of the role of Dra in intestinal sulfate transport and in the malignant phenotype.

  5. Novel Monoclonal Antibodies Recognizing Human Prostate-Specific Membrane Antigen (PSMA) as Research and Theranostic Tools.

    Science.gov (United States)

    Nováková, Zora; Foss, Catherine A; Copeland, Benjamin T; Morath, Volker; Baranová, Petra; Havlínová, Barbora; Skerra, Arne; Pomper, Martin G; Barinka, Cyril

    2017-05-01

    Prostate-specific membrane antigen (PSMA) is a validated target for the imaging and therapy of prostate cancer. Here, we report the detailed characterization of four novel murine monoclonal antibodies (mAbs) recognizing human PSMA as well as PSMA orthologs from different species. Performance of purified mAbs was assayed using a comprehensive panel of in vitro experimental setups including Western blotting, immunofluorescence, immunohistochemistry, ELISA, flow cytometry, and surface-plasmon resonance. Furthermore, a mouse xenograft model of prostate cancer was used to compare the suitability of the mAbs for in vivo applications. All mAbs demonstrate high specificity for PSMA as documented by the lack of cross-reactivity to unrelated human proteins. The 3F11 and 1A11 mAbs bind linear epitopes spanning residues 226-243 and 271-288 of human PSMA, respectively. 3F11 is also suitable for the detection of PSMA orthologs from mouse, pig, dog, and rat in experimental setups where the denatured form of PSMA is used. 5D3 and 5B1 mAbs recognize distinct surface-exposed conformational epitopes and are useful for targeting PSMA in its native conformation. Most importantly, using a mouse xenograft model of prostate cancer we show that both the intact 5D3 and its Fab fragment are suitable for in vivo imaging. With apparent affinities of 0.14 and 1.2 nM as determined by ELISA and flow cytometry, respectively, 5D3 has approximately 10-fold higher affinity for PSMA than the clinically validated mAb J591 and, therefore, is a prime candidate for the development of next-generation theranostics to target PSMA. Prostate 77:749-764, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. A remote arene-binding site on prostate specific membrane antigen revealed by antibody-recruiting small molecules

    Czech Academy of Sciences Publication Activity Database

    Zhang, A.X.; Murelli, R.P.; Bařinka, Cyril; Michel, J.; Cocleaza, A.; Jorgensen, W.L.; Lubkowski, J.; Spiegel, D.A.

    2010-01-01

    Roč. 132, č. 36 (2010), s. 12711-12716 ISSN 0002-7863 Institutional research plan: CEZ:AV0Z50520701 Keywords : Prostate -specific membrane antigen * antibody recruiting molecules * Structure-activity relationship Subject RIV: CE - Biochemistry Impact factor: 9.019, year: 2010

  7. Stage-specific synthesis and fucosylation of plasma membrane proteins by mouse pachytene spermatocytes and round spermatids in culture

    International Nuclear Information System (INIS)

    Gerton, G.L.; Millette, C.F.

    1986-01-01

    Little is known about the ability of mammalian spermatogenic cells to synthesize plasma membrane components in the presence or absence of Sertoli cells. In this study, purified populations (greater than 90%) of pachytene spermatocytes or round spermatids were isolated by unit gravity sedimentation and cultured for 20-24 h in the presence of [ 35 S]methionine or [ 3 H] fucose. Cell viabilities remained over 90% during the course of these experiments. Plasma membranes were purified from these cells and analyzed by two-dimensional gel electrophoresis. Qualitatively, the same plasma membrane proteins were synthesized by both cell types with the exception of the major Concanavalin A-binding glycoprotein, p151; the synthesis of p151 is greatly diminished or inhibited after meiosis. [3H]Fucose was incorporated into at least 6 common glycoproteins of both cells. Eight components fucosylated with molecular weights from 35,000 to 120,000 were specific to pachytene spermatocyte membranes. One fast-migrating fucosylated component may represent an uncharacterized lipid whose synthesis is terminated after meiosis. Round spermatids specifically fucosylated two components with molecular weights of 45,000 and 80,000. These results demonstrate the viability of germ cells of the male mouse in short-term culture and show that they are capable of synthesizing and fucosylating plasma membrane components in the absence of Sertoli cells

  8. DMPD: CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multipleligand specificities and functions. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available ) (.html) (.csml) Show CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multipleligand specificities and function...d NK cell membrane receptor with multipleligand specificities and functions. Authors Ross GD, Vetvicka V. Pu...igand specificities and functions. Ross GD, Vetvicka V. Clin Exp Immunol. 1993 May;92(2):181-4. (.png) (.svg...8485905 CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multiplel

  9. Specific oriented metal-organic framework membranes and their facet-tuned separation performance.

    Science.gov (United States)

    Mao, Yiyin; Su, Binbin; Cao, Wei; Li, Junwei; Ying, Yulong; Ying, Wen; Hou, Yajun; Sun, Luwei; Peng, Xinsheng

    2014-09-24

    Modulating the crystal morphology, or the exposed crystal facets, of metal-organic frameworks (MOFs) expands their potential applications in catalysis, adsorption, and separation. In this article, by immobilizing the citrate modulators on Au nanoparticles and subsequently being fixed on solid copper hydroxide nanostrands, a well-intergrown and oriented HKUST-1 cube crystal membrane was formed at room temperature. In contrast, in the absence of Au nanoparticles, well-intergrown and oriented cuboctahedron and octahedron membranes were formed in water/ethanol and ethanol, respectively. The gas separation performances of these HKUST-1 membranes were tuned via their exposed facets with defined pore sizes. The HKUST-1 cube membrane with exposed {001} facets demonstrated the highest permeance but lowest gas binary separation factors, while the octahedron membrane with exposed {111} facets presented the highest separation factors but lowest permeance, since the window size of {111} facets is 0.46 nm which is smaller than 0.9 nm of {001} facets. Separation of 0.38 nm CO2 from 0.55 nm SF6 was realized by the HKUST-1 octahedron membrane. As a proof of concept, this will open a new way to design MOF-related separation membranes by facet controlling.

  10. Reproductive organ and vascular specific promoter of the rice plasma membrane Ca2+ATPase mediates environmental stress responses in plants.

    Science.gov (United States)

    Huda, Kazi Md Kamrul; Banu, Mst Sufara Akhter; Pathi, Krishna Mohan; Tuteja, Narendra

    2013-01-01

    Plasma membrane Ca(2+)ATPase is a transport protein in the plasma membrane of cells and helps in removal of calcium (Ca(2+)) from the cell, hence regulating Ca(2+) level within cells. Though plant Ca(2+)ATPases have been shown to be involved in plant stress responses but their promoter regions have not been well studied. The 1478 bp promoter sequence of rice plasma membrane Ca(2+)ATPase contains cis-acting elements responsive to stresses and plant hormones. To identify the functional region, serial deletions of the promoter were fused with the GUS sequence and four constructs were obtained. These were differentially activated under NaCl, PEG cold, methyl viologen, abscisic acid and methyl jasmonate treatments. We demonstrated that the rice plasma membrane Ca(2+)ATPase promoter is responsible for vascular-specific and multiple stress-inducible gene expression. Only full-length promoter showed specific GUS expression under stress conditions in floral parts. High GUS activity was observed in roots with all the promoter constructs. The -1478 to -886 bp flanking region responded well upon treatment with salt and drought. Only the full-length promoter presented cold-induced GUS expression in leaves, while in shoots slight expression was observed for -1210 and -886 bp flanking region. The -1210 bp deletion significantly responded to exogenous methyl viologen and abscisic acid induction. The -1210 and -886 bp flanking region resulted in increased GUS activity in leaves under methyl jasmonate treatments, whereas in shoots the -886 bp and -519 bp deletion gave higher expression. Salicylic acid failed to induce GUS activities in leaves for all the constructs. The rice plasma membrane Ca(2+)ATPase promoter is a reproductive organ-specific as well as vascular-specific. This promoter contains drought, salt, cold, methyl viologen, abscisic acid and methyl jasmonate related cis-elements, which regulated gene expression. Overall, the tissue-specificity and inducible nature of this

  11. Studying the Effect of Tunnel Depth Variation on the Specific Energy of TBM, Case Study: Karaj–Tehran (Iran Water Conveyance Tunnel

    Directory of Open Access Journals (Sweden)

    Majid Mirahmadi

    2016-09-01

    Full Text Available The tunnel-boring machine (TBM is a common piece of equipment used in tunneling projects. For planning a mechanical excavation project, prediction of TBM performance and the specification of design elements such as required forces are critical. The specific energy of excavation (SE, i.e. drilling energy consumption per unit volume of rock mass, is a crucial parameter for performance prediction of a TBM. In this study, the effect of variation of tunnel depth on SE by considering the post-failure behavior of rock mass was investigated. Several new relations between SE and tunnel depth are proposed according to the statistical analysis obtained from Karaj – Tehran Water Conveyance Tunnel real data. The results showed that there is a direct relation between both parameters and. Polynomial equations are proposed as the best expression of the correlation between these parameters.

  12. An acid phosphatase in the plasma membranes of human astrocytoma showing marked specificity toward phosphotyrosine protein.

    OpenAIRE

    Leis, J F; Kaplan, N O

    1982-01-01

    The plasma membrane from the human tumor astrocytoma contains an active acid phosphatase activity based on hydrolysis of p-nitrophenyl phosphate. Other acid phosphatase substrates--beta-glycerophosphate, O-phosphorylcholine, and 5'-AMP--are not hydrolyzed significantly. The phosphatase activity is tartrate insensitive and is stimulated by Triton X-100 and EDTA. Of the three known phosphoamino acids, only free O-phosphotyrosine is hydrolyzed by the membrane phosphatase activity. Other acid pho...

  13. Prostate-Specific Membrane Antigen Targeted Gold Nanoparticles for Theranostics of Prostate Cancer.

    Science.gov (United States)

    Mangadlao, Joey Dacula; Wang, Xinning; McCleese, Christopher; Escamilla, Maria; Ramamurthy, Gopalakrishnan; Wang, Ziying; Govande, Mukul; Basilion, James P; Burda, Clemens

    2018-04-24

    Prostate cancer is one of the most common cancers and among the leading causes of cancer deaths in the United States. Men diagnosed with the disease typically undergo radical prostatectomy, which often results in incontinence and impotence. Recurrence of the disease is often experienced by most patients with incomplete prostatectomy during surgery. Hence, the development of a technique that will enable surgeons to achieve a more precise prostatectomy remains an open challenge. In this contribution, we report a theranostic agent (AuNP-5kPEG-PSMA-1-Pc4) based on prostate-specific membrane antigen (PSMA-1)-targeted gold nanoparticles (AuNPs) loaded with a fluorescent photodynamic therapy (PDT) drug, Pc4. The fabricated nanoparticles are well-characterized by spectroscopic and imaging techniques and are found to be stable over a wide range of solvents, buffers, and media. In vitro cellular uptake experiments demonstrated significantly higher nanoparticle uptake in PSMA-positive PC3pip cells than in PSMA-negative PC3flu cells. Further, more complete cell killing was observed in Pc3pip than in PC3flu cells upon exposure to light at different doses, demonstrating active targeting followed by Pc4 delivery. Likewise, in vivo studies showed remission on PSMA-expressing tumors 14 days post-PDT. Atomic absorption spectroscopy revealed that targeted AuNPs accumulate 4-fold higher in PC3pip than in PC3flu tumors. The nanoparticle system described herein is envisioned to provide surgical guidance for prostate tumor resection and therapeutic intervention when surgery is insufficient.

  14. Strain specific variation of outer membrane proteins of wild Yersinia pestis strains subjected to different growth temperatures

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme Coutinho Abath

    1990-03-01

    Full Text Available Three Yersinia pestis strains isolated from humans and one laboratory strain (EV76 were grown in rich media at 28§C and 37§C and their outer membrane protein composition compared by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-Page. Several proteins with molecular weights ranging from 34 kDa to 7 kDa were observed to change in relative abundance in samples grown at different temperatures. At least seven Y. pestis outer membrane proteins showed a temperature-dependent and strain-specific behaviour. Some differences between the outer membrane proteins of full-pathogenic wild isolates and the EV76 strain could aldso be detected and the relevance of this finding on the use of laboratory strains as a reference to the study of Y. pestis biological properties is discuted.

  15. Aluminum ions alter the function of non-specific phospholipase C through the changes in plasma membrane physical properties.

    Science.gov (United States)

    Pejchar, Přemysl; Martinec, Jan

    2015-01-01

    The first indication of the aluminum (Al) toxicity in plants growing in acidic soils is the cessation of root growth, but the detailed mechanism of Al effect is unknown. Here we examined the impact of Al stress on the activity of non-specific phospholipase C (NPC) in the connection with the processes related to the plasma membrane using fluorescently labeled phosphatidylcholine. We observed a rapid and significant decrease of labeled diacylglycerol (DAG), product of NPC activity, in Arabidopsis seedlings treated with AlCl₃. Interestingly, an application of the membrane fluidizer, benzyl alcohol, restored the level of DAG during Al treatment. Our observations suggest that the activity of NPC is affected by Al-induced changes in plasma membrane physical properties.

  16. 21-Methylpyrenyl-cholesterol stably and specifically associates with lipoprotein peripheral hemi-membrane: A new labelling tool

    Energy Technology Data Exchange (ETDEWEB)

    Gaibelet, Gérald [INSERM U563, CHU Purpan, Toulouse (France); CEA, SB2SM and UMR8221 CNRS, IBiTec-Saclay, Gif-sur-Yvette (France); Tercé, François [Université Toulouse III, UMR 1048, Toulouse (France); INSERM U1048, Toulouse (France); Bertrand-Michel, Justine [Université Toulouse III, UMR 1048, Toulouse (France); INSERM U1048, Lipidomic Platform Metatoul, Toulouse (France); Allart, Sophie [Plateau Technique d’Imagerie Cellulaire, INSERM U1043, Toulouse (France); Azalbert, Vincent [Université Toulouse III, UMR 1048, Toulouse (France); INSERM U1048, Toulouse (France); Lecompte, Marie-France [INSERM U563, Faculté de Médecine de Rangueil, Toulouse (France); Collet, Xavier [Université Toulouse III, UMR 1048, Toulouse (France); INSERM U1048, Toulouse (France); Orlowski, Stéphane, E-mail: stephane.orlowski@cea.fr [INSERM U563, CHU Purpan, Toulouse (France); CEA, SB2SM and UMR8221 CNRS, IBiTec-Saclay, Gif-sur-Yvette (France)

    2013-11-01

    Highlights: •21-Methylpyrenyl-cholesterol specifically and stably associates to lipoproteins. •It is not esterified by LCAT, and thus reliably labels their peripheral hemi-membrane. •HDL vs. LDL are well distinguishable by various fluorescent labelling characteristics. •LDL peripheral hemi-membrane harbors cholesterol-rich ordered lipid (micro)domains. •Cultured cells can be stained by such labelled lipoproteins-mediated delivery. -- Abstract: Lipoproteins are important biological components. However, they have few convenient fluorescent labelling probes currently reported, and their physiological reliability can be questioned. We compared the association of two fluorescent cholesterol derivatives, 22-nitrobenzoxadiazole-cholesterol (NBD-Chol) and 21-methylpyrenyl-cholesterol (Pyr-met-Chol), to serum lipoproteins and to purified HDL and LDL. Both lipoproteins could be stably labelled by Pyr-met-Chol, but virtually not by NBD-Chol. At variance with NBD-Chol, LCAT did not esterify Pyr-met-Chol. The labelling characteristics of lipoproteins by Pyr-met-Chol were well distinguishable between HDL and LDL, regarding dializability, associated probe amount and labelling kinetics. We took benefit of the pyrene labelling to approach the structural organization of LDL peripheral hemi-membrane, since Pyr-met-Chol-labelled LDL, but not HDL, presented a fluorescence emission of pyrene excimers, indicating that the probe was present in an ordered lipid micro-environment. Since the peripheral membrane of LDL contains more sphingomyelin (SM) than HDL, this excimer formation was consistent with the existence of cholesterol- and SM-enriched lipid microdomains in LDL, as already suggested in model membranes of similar composition and reminiscent to the well-described “lipid rafts” in bilayer membranes. Finally, we showed that Pyr-met-Chol could stain cultured PC-3 cells via lipoprotein-mediated delivery, with a staining pattern well different to that observed with NBD

  17. 21-Methylpyrenyl-cholesterol stably and specifically associates with lipoprotein peripheral hemi-membrane: A new labelling tool

    International Nuclear Information System (INIS)

    Gaibelet, Gérald; Tercé, François; Bertrand-Michel, Justine; Allart, Sophie; Azalbert, Vincent; Lecompte, Marie-France; Collet, Xavier; Orlowski, Stéphane

    2013-01-01

    Highlights: •21-Methylpyrenyl-cholesterol specifically and stably associates to lipoproteins. •It is not esterified by LCAT, and thus reliably labels their peripheral hemi-membrane. •HDL vs. LDL are well distinguishable by various fluorescent labelling characteristics. •LDL peripheral hemi-membrane harbors cholesterol-rich ordered lipid (micro)domains. •Cultured cells can be stained by such labelled lipoproteins-mediated delivery. -- Abstract: Lipoproteins are important biological components. However, they have few convenient fluorescent labelling probes currently reported, and their physiological reliability can be questioned. We compared the association of two fluorescent cholesterol derivatives, 22-nitrobenzoxadiazole-cholesterol (NBD-Chol) and 21-methylpyrenyl-cholesterol (Pyr-met-Chol), to serum lipoproteins and to purified HDL and LDL. Both lipoproteins could be stably labelled by Pyr-met-Chol, but virtually not by NBD-Chol. At variance with NBD-Chol, LCAT did not esterify Pyr-met-Chol. The labelling characteristics of lipoproteins by Pyr-met-Chol were well distinguishable between HDL and LDL, regarding dializability, associated probe amount and labelling kinetics. We took benefit of the pyrene labelling to approach the structural organization of LDL peripheral hemi-membrane, since Pyr-met-Chol-labelled LDL, but not HDL, presented a fluorescence emission of pyrene excimers, indicating that the probe was present in an ordered lipid micro-environment. Since the peripheral membrane of LDL contains more sphingomyelin (SM) than HDL, this excimer formation was consistent with the existence of cholesterol- and SM-enriched lipid microdomains in LDL, as already suggested in model membranes of similar composition and reminiscent to the well-described “lipid rafts” in bilayer membranes. Finally, we showed that Pyr-met-Chol could stain cultured PC-3 cells via lipoprotein-mediated delivery, with a staining pattern well different to that observed with NBD

  18. Simultaneous Characterization of Instantaneous Young’s Modulus and Specific Membrane Capacitance of Single Cells Using a Microfluidic System

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    2015-01-01

    Full Text Available This paper presents a microfluidics-based approach capable of continuously characterizing instantaneous Young’s modulus (Einstantaneous and specific membrane capacitance (Cspecific membrane of suspended single cells. In this method, cells were aspirated through a constriction channel while the cellular entry process into the constriction channel was recorded using a high speed camera and the impedance profiles at two frequencies (1 kHz and 100 kHz were simultaneously measured by a lock-in amplifier. Numerical simulations were conducted to model cellular entry process into the constriction channel, focusing on two key parameters: instantaneous aspiration length (Linstantaneous and transitional aspiration length (Ltransitional, which was further translated to Einstantaneous. An equivalent distribution circuit model for a cell travelling in the constriction channel was used to determine Cspecific membrane. A non-small-cell lung cancer cell line 95C (n = 354 was used to evaluate this technique, producing Einstantaneous of 2.96 ± 0.40 kPa and Cspecific membrane of 1.59 ± 0.28 μF/cm2. As a platform for continuous and simultaneous characterization of cellular Einstantaneous and Cspecific membrane, this approach can facilitate a more comprehensive understanding of cellular biophysical properties.

  19. Specific chlamydial inclusion membrane proteins associate with active Src family kinases in microdomains that interact with the host microtubule network.

    Science.gov (United States)

    Mital, Jeffrey; Miller, Natalie J; Fischer, Elizabeth R; Hackstadt, Ted

    2010-09-01

    Chlamydiae are Gram-negative obligate intracellular bacteria that cause diseases with significant medical and economic impact. Chlamydia trachomatis replicates within a vacuole termed an inclusion, which is extensively modified by the insertion of a number of bacterial effector proteins known as inclusion membrane proteins (Incs). Once modified, the inclusion is trafficked in a dynein-dependent manner to the microtubule-organizing centre (MTOC), where it associates with host centrosomes. Here we describe a novel structure on the inclusion membrane comprised of both host and bacterial proteins. Members of the Src family of kinases are recruited to the chlamydial inclusion in an active form. These kinases display a distinct, localized punctate microdomain-like staining pattern on the inclusion membrane that colocalizes with four chlamydial inclusion membrane proteins (Incs) and is enriched in cholesterol. Biochemical studies show that at least two of these Incs stably interact with one another. Furthermore, host centrosomes associate with these microdomain proteins in C. trachomatis-infected cells and in uninfected cells exogenously expressing one of the chlamydial effectors. Together, the data suggest that a specific structure on the C. trachomatis inclusion membrane may be responsible for the known interactions of chlamydiae with the microtubule network and resultant effects on centrosome stability.

  20. Applicability of a novel osmotic membrane bioreactor using a specific draw solution in wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Nguyen Cong [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Chen, Shiao-Shing, E-mail: f10919@ntut.edu.tw [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Nguyen, Hau Thi [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Ngo, Huu Hao, E-mail: h.ngo@uts.edu.au [School of Civil and Environmental Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Broadway, NSW 2007 (Australia); Guo, Wenshan [School of Civil and Environmental Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Broadway, NSW 2007 (Australia); Hao, Chan Wen [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Lin, Po-Hsun [New Materials Research and Development Dept., China Steel Corporation, Taiwan, ROC (China)

    2015-06-15

    This study aims to develop a new osmotic membrane bioreactor by combining a moving bed biofilm reactor (MBBR) with forward osmosis membrane bioreactor (FOMBR) to treat wastewater. Ethylenediaminetetraacetic acid disodium salt coupled with polyethylene glycol tert-octylphenyl ether was used as an innovative draw solution in this membrane hybrid system (MBBR–OsMBR) for minimizing the reverse salt flux and maintaining a healthy environment for the microorganism community. The results showed that the hybrid system achieved a stable water flux of 6.94 L/m{sup 2} h and low salt accumulation in the bioreactor for 68 days of operation. At a filling rate of 40% (by volume of the bioreactor) of the polyethylene balls used as carriers, NH{sub 4}{sup +}-N and PO{sub 4}{sup 3−}-P were almost removed (> 99%) while producing relatively low NO{sub 3}{sup −}-N and NO{sub 2}{sup −}-N in the effluent (e.g. < 0.56 and 0.96 mg/L, respectively). Furthermore, from analysis based on scanning electron microscopy, Fourier transform infrared spectroscopy, and fluorescence emission–excitation matrix spectrophotometry, there was a thin gel-like fouling layer on the FO membrane, which composed of bacteria as well as biopolymers and protein-like substances. Nonetheless, the formation of these fouling layers of the FO membrane in MBBR–OsMBR was reversible and removed by a physical cleaning technique. - Highlights: • A novel osmotic membrane bioreactor (MBBR–OsMBR) using a novel draw solution (DS) was developed. • The MBBR–OsMBR system successfully reduced membrane fouling. • EDTA sodium coupled with Triton X-100 as novel DS resulted in low salt accumulation. • Nitrification and denitrification were well performed in a biocarrier. • The MBBR–OsMBR could remarkably remove phosphorus.

  1. Applicability of a novel osmotic membrane bioreactor using a specific draw solution in wastewater treatment

    International Nuclear Information System (INIS)

    Nguyen, Nguyen Cong; Chen, Shiao-Shing; Nguyen, Hau Thi; Ngo, Huu Hao; Guo, Wenshan; Hao, Chan Wen; Lin, Po-Hsun

    2015-01-01

    This study aims to develop a new osmotic membrane bioreactor by combining a moving bed biofilm reactor (MBBR) with forward osmosis membrane bioreactor (FOMBR) to treat wastewater. Ethylenediaminetetraacetic acid disodium salt coupled with polyethylene glycol tert-octylphenyl ether was used as an innovative draw solution in this membrane hybrid system (MBBR–OsMBR) for minimizing the reverse salt flux and maintaining a healthy environment for the microorganism community. The results showed that the hybrid system achieved a stable water flux of 6.94 L/m 2 h and low salt accumulation in the bioreactor for 68 days of operation. At a filling rate of 40% (by volume of the bioreactor) of the polyethylene balls used as carriers, NH 4 + -N and PO 4 3− -P were almost removed (> 99%) while producing relatively low NO 3 − -N and NO 2 − -N in the effluent (e.g. < 0.56 and 0.96 mg/L, respectively). Furthermore, from analysis based on scanning electron microscopy, Fourier transform infrared spectroscopy, and fluorescence emission–excitation matrix spectrophotometry, there was a thin gel-like fouling layer on the FO membrane, which composed of bacteria as well as biopolymers and protein-like substances. Nonetheless, the formation of these fouling layers of the FO membrane in MBBR–OsMBR was reversible and removed by a physical cleaning technique. - Highlights: • A novel osmotic membrane bioreactor (MBBR–OsMBR) using a novel draw solution (DS) was developed. • The MBBR–OsMBR system successfully reduced membrane fouling. • EDTA sodium coupled with Triton X-100 as novel DS resulted in low salt accumulation. • Nitrification and denitrification were well performed in a biocarrier. • The MBBR–OsMBR could remarkably remove phosphorus

  2. /sup 125/I-human epidermal growth factor specific binding to placentas and fetal membranes from varoius pregnancy states

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, G.E.; Siddiqi, T.A.; Rao, Ch. V.; Carman, F.R.

    1988-01-01

    Specific binding of /sup 125/I-human epidermal growth factor (hEGF) to homogenates of term human placentas and fetal membranes from normal and appropriate for gestational age (N = 20), intrauterine growth retarded (N = 9), twin (N = 11), White class AB diabetic (N = 12), and large for gestational age (N = 13) pregnancies was measured. In all pregnancy states, placentas bound approximately four times more /sup 125/I-hEGF than did fetal membranes (P<0.0001). There was no significant differnce in /sup 125/I-hEGF binding to fetal membranes from the various pregnancy states (P<0.05). /sup 125/I-hEGF specific binding to placentas from intrauterine growth retarded or twin pregnancies was significantly greater compared with placentas from normal and appropriate for gestational age pregnancies (P<0.05). The binding to placentas from pregnancies complicated by White class AB diabetes or large for gestational age infants, on the other hand, was not significantly different from that to placentas from normal and appropriate for gestational age pregnancies. /sup 125/I-hEGF specific binding did not differ between placentas from intrauterine growth retarded or twin pregnancies (P<0.05). Placental and fetal membrane /sup 125/I-hEGF binding did not vary with fetal sex, maternal race, placental weight, or gestational age between 37 to 42 weeks (P<0.05). Placental but not fetal membrane /sup 125/I-hEGF binding increased with increasing infant weight when appropriate for gestational age and large for gestational age infants were included (P<0.05, r = 0.38, N = 32) but not for intrauterine growth retarded, appropriate for gestational age, or large for gestational age infants alone.

  3. Correction of fluorescence for depth-specific optical and vascular properties using reflectance and differential path-length spectroscopy during PDT

    Science.gov (United States)

    van Zaane, F.; Middelburg, T. A.; de Bruijn, H. S.; van der Ploeg-van den Heuvel, A.; de Haas, E. R. M.; Sterenborg, H. J. C. M.; Neumann, H. A. M.; Robinson, D. J.

    2009-06-01

    Introduction: The rate of PpIX fluorescence photobleaching is routinely used as a dose metric for ALA-PDT. Diffuse reflection spectroscopy is often used to account for variations in tissue optical properties at the photosensitizer excitation and emission bands. It can be used to quantify changes in vascular parameters, such as blood volume fraction and saturation, and can aid understanding of tissue response to PDT. The volume and(/or) depth over which these signals are acquired are critical. The aim of this study is to use quantitative reflectance spectroscopy (DPS) to correct fluorescence for changes in tissue optical properties and monitor PDT. Materials & Methods: ALA was topically applied to hairless mice skin and the incubated spot was treated with PDT according to fractionated illumination schemes. DPS measurements of vascular parameters and optical properties were performed directly before and after illumination. Both the differential signal, delivery-and-collection-fiber signal and the collection fiber signal, which all probe different measurement volumes, are analyzed. Results & Conclusions: Analysis of DPS measurements shows that at the depth where most fluorescence originates, there is almost no blood present. During PDT vascular parameters at this depth stay constant. In more oxygenated layers of the tissue, the optical properties do change during PDT, suggesting that only a small part of PpIX fluorescence originates from the interesting depths where vascular response occurs. Correcting fluorescence emission spectra for optical changes at specific depths and not for the total of changes in a larger volume, as is usually done now, can improve PpIX photobleaching based treatment monitoring.

  4. Biochemical characterization of prostate-specific membrane antigen from canine prostate carcinoma cells.

    Science.gov (United States)

    Wu, Lisa Y; Johnson, Jacqueline M; Simmons, Jessica K; Mendes, Desiree E; Geruntho, Jonathan J; Liu, Tiancheng; Dirksen, Wessel P; Rosol, Thomas J; Davis, William C; Berkman, Clifford E

    2014-05-01

    Prostate-specific membrane antigen (PSMA) remains an important target for diagnostic and therapeutic application for human prostate cancer. Model cell lines have been recently developed to study canine prostate cancer but their PSMA expression and enzymatic activity have not been elucidated. The present study was focused on determining PSMA expression in these model canine cell lines and the use of fluorescent small-molecule enzyme inhibitors to detect canine PSMA expression by flow cytometry. Western blot and RT-PCR were used to determine the transcriptional and translational expression of PSMA on the canine cell lines Leo and Ace-1. An endpoint HPLC-based assay was used to monitor the enzymatic activity of canine PSMA and the potency of enzyme inhibitors. Flow cytometry was used to detect the PSMA expressed on Leo and Ace-1 cells using a fluorescently tagged PSMA enzyme inhibitor. Canine PSMA expression on the Leo cell line was confirmed by Western blot and RT-PCR, the enzyme activity, and flow cytometry. Kinetic parameters Km and Vmax of PSMA enzymatic activity for the synthetic substrate (PABGγG) were determined to be 393 nM and 220 pmol min(-1)  mg protein(-1) , respectively. The inhibitor core 1 and fluorescent inhibitor 2 were found to be potent reversible inhibitors (IC50  = 13.2 and 1.6 nM, respectively) of PSMA expressed on the Leo cell line. Fluorescent labeling of Leo cells demonstrated that the fluorescent PSMA inhibitor 2 can be used for the detection of PSMA-positive canine prostate tumor cells. Expression of PSMA on Ace-1 was low and not detectable by flow cytometry. The results described herein have demonstrated that PSMA is expressed on canine prostate tumor cells and exhibits similar enzymatic characteristics as human PSMA. The findings show that the small molecule enzyme inhibitors currently being studied for use in diagnosis and therapy of human prostate cancer can also be extended to include canine prostate cancer. Importantly

  5. Tissue expression and enzymologic characterization of human prostate specific membrane antigen and its rat and pig orthologs

    Czech Academy of Sciences Publication Activity Database

    Rovenská, Miroslava; Hlouchová, Klára; Šácha, Pavel; Mlčochová, Petra; Horák, Vratislav; Zámečník, J.; Bařinka, C.; Konvalinka, Jan

    2008-01-01

    Roč. 68, č. 2 (2008), s. 171-182 ISSN 0270-4137 R&D Projects: GA MŠk 1M0508; GA ČR GA524/04/0102 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50450515 Keywords : prostate specific membrane antigen * glutamate carboxypeptidase II * animal orthologs * prostate cancer * animal model Subject RIV: CE - Biochemistry Impact factor: 3.069, year: 2008

  6. Identification of leukotriene D4 specific binding sites in the membrane preparation isolated from guinea pig lung

    International Nuclear Information System (INIS)

    Mong, S.; Wu, H.L.; Clark, M.A.; Stadel, J.M.; Gleason, J.G.; Crooke, S.T.

    1984-01-01

    A radioligand binding assay has been established to study leukotriene specific binding sites in the guinea pig and rabbit tissues. Using high specific activity [ 3 H]-leukotriene D4 [( 3 H]-LTD4), in the presence or absence of unlabeled LTD4, the diastereoisomer of LTD4 (5R,6S-LTD4), leukotriene E4 (LTE4) and the end-organ antagonist, FPL 55712, the authors have identified specific binding sites for [ 3 H]-LTD4 in the crude membrane fraction isolated from guinea pig lung. The time required for [ 3 H]-LTD4 binding to reach equilibrium was approximately 20 to 25 min at 37 degrees C in the presence of 10 mM Tris-HCl buffer (pH 7.5) containing 150 mM NaCl. The binding of [ 3 H]-LTD4 to the specific sites was saturable, reversible and stereospecific. The maximal number of binding sites (Bmax), derived from Scatchard analysis, was approximately 320 +/- 200 fmol per mg of crude membrane protein. The dissociation constants, derived from kinetic and saturation analyses, were 9.7 nM and 5 +/- 4 nM, respectively. The specific binding sites could not be detected in the crude membrane fraction prepared from guinea pig ileum, brain and liver, or rabbit lung, trachea, ileum and uterus. In radioligand competition experiments, LTD4, FPL 55712 and 5R,6S-LTD4 competed with [ 3 H]-LTD4. The metabolic inhibitors of arachidonic acid and SKF 88046, an antagonist of the indirectly-mediated actions of LTD4, did not significantly compete with [ 3 H]-LTD4 at the specific binding sites. These correlations indicated that these specific binding sites may be the putative leukotriene receptors in the guinea-pig lung

  7. 125I-human epidermal growth factor specific binding to placentas and fetal membranes from varoius pregnancy states

    International Nuclear Information System (INIS)

    Hofmann, G.E.; Siddiqi, T.A.; Rao, Ch. V.; Carman, F.R.

    1988-01-01

    Specific binding of 125 I-human epidermal growth factor (hEGF) to homogenates of term human placentas and fetal membranes from normal and appropriate for gestational age (N = 20), intrauterine growth retarded (N = 9), twin (N = 11), White class A/B diabetic (N = 12), and large for gestational age (N = 13) pregnancies was measured. In all pregnancy states, placentas bound approximately four times more 125 I-hEGF than did fetal membranes (P 125 I-hEGF binding to fetal membranes from the various pregnancy states (P 125 I-hEGF specific binding to placentas from intrauterine growth retarded or twin pregnancies was significantly greater compared with placentas from normal and appropriate for gestational age pregnancies (P 125 I-hEGF specific binding did not differ between placentas from intrauterine growth retarded or twin pregnancies (P 125 I-hEGF binding did not vary with fetal sex, maternal race, placental weight, or gestational age between 37 to 42 weeks (P 125 I-hEGF binding increased with increasing infant weight when appropriate for gestational age and large for gestational age infants were included (P<0.05, r = 0.38, N = 32) but not for intrauterine growth retarded, appropriate for gestational age, or large for gestational age infants alone. (author)

  8. Epidermal growth factor-induced mobilization of a ganglioside-specific sialidase (NEU3) to membrane ruffles

    International Nuclear Information System (INIS)

    Yamaguchi, Kazunori; Hata, Keiko; Wada, Tadashi; Moriya, Setsuko; Miyagi, Taeko

    2006-01-01

    Human ganglioside-specific sialidase, NEU3, localized at cell membranes is thought to regulate various biological processes at cell surfaces. We here explored functional subcellular localization of the sialidase by immunofluorescence and found accumulation at leading edges of cell membranes in the presence of serum in culture. In response to EGF, the sialidase redistributed rapidly to ruffling cell membranes of squamous carcinoma A431 cells and co-localized with Rac-1. NEU3 overexpression enhanced Rac-1 activation and cell migration as compared with controls in HeLa cells as well as in A431 cells. Consistent with co-localization with Rac-1 by immunofluorescence, NEU3 was found to co-precipitate with activated Rac bound to GST-PAK-1 fusion protein. NEU3 silencing by siRNA, in contrast, resulted in inhibition of Rac-1 activation. These results indicate that NEU3 is able to mobilize to membrane ruffles in response to growth stimuli and activate the Rac-1 signaling by co-localization with Rac-1, leading to increased cell motility

  9. Tissue-specific expression of the gene for a putative plasma membrane H(+)-ATPase in a seagrass.

    Science.gov (United States)

    Fukuhara, T; Pak, J Y; Ohwaki, Y; Tsujimura, H; Nitta, T

    1996-01-01

    A cDNA clone corresponding to the gene (ZHA1) for a putative plasma membrane H(+)-ATPase of a seagrass (Zostera marina L.) was isolated and sequenced. Comparison of the amino acid predicted sequence from the nucleotide sequence of ZHA1 with those encoded by known genes for plasma membrane H(+)-ATPases from other plants indicated that ZHA1 is most similar to the gene (PMA4) for a plasma membrane H(+)-ATPase in a tobacco (84.4%). Northern hybridization indicated that ZHA1 was strongly expressed in mature leaves, which are exposed to seawater and have the ability of tolerate salinity; ZHA1 was weakly expressed in immature leaves, which are protected from seawater by tightly enveloping sheaths and are sensitive to salinity. In mature leaves, in situ hybridization revealed that ZHA1 was expressed specifically in epidermal cells, the plasma membranes of which were highly invaginated and morphologically similar to those of typical transfer cells. Therefore, the differentiation of the transfer cell-like structures, accompanied by the high-level expression of ZHA1, in the epidermal cells of mature leaves in particular may be important for the excretion of salt by these cells. PMID:8587992

  10. Pathogen-Specific Binding Soluble Down Syndrome Cell Adhesion Molecule (Dscam Regulates Phagocytosis via Membrane-Bound Dscam in Crab

    Directory of Open Access Journals (Sweden)

    Xue-Jie Li

    2018-04-01

    Full Text Available The Down syndrome cell adhesion molecule (Dscam gene is an extraordinary example of diversity that can produce thousands of isoforms and has so far been found only in insects and crustaceans. Cumulative evidence indicates that Dscam may contribute to the mechanistic foundations of specific immune responses in insects. However, the mechanism and functions of Dscam in relation to pathogens and immunity remain largely unknown. In this study, we identified the genome organization and alternative Dscam exons from Chinese mitten crab, Eriocheir sinensis. These variants, designated EsDscam, potentially produce 30,600 isoforms due to three alternatively spliced immunoglobulin (Ig domains and a transmembrane domain. EsDscam was significantly upregulated after bacterial challenge at both mRNA and protein levels. Moreover, bacterial specific EsDscam isoforms were found to bind specifically with the original bacteria to facilitate efficient clearance. Furthermore, bacteria-specific binding of soluble EsDscam via the complete Ig1–Ig4 domain significantly enhanced elimination of the original bacteria via phagocytosis by hemocytes; this function was abolished by partial Ig1–Ig4 domain truncation. Further studies showed that knockdown of membrane-bound EsDscam inhibited the ability of EsDscam with the same extracellular region to promote bacterial phagocytosis. Immunocytochemistry indicated colocalization of the soluble and membrane-bound forms of EsDscam at the hemocyte surface. Far-Western and coimmunoprecipitation assays demonstrated homotypic interactions between EsDscam isoforms. This study provides insights into a mechanism by which soluble Dscam regulates hemocyte phagocytosis via bacteria-specific binding and specific interactions with membrane-bound Dscam as a phagocytic receptor.

  11. Membrane topology and identification of key residues of EaDAcT, a plant MBOAT with unusual substrate specificity.

    Science.gov (United States)

    Tran, Tam N T; Shelton, Jennifer; Brown, Susan; Durrett, Timothy P

    2017-10-01

    Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) catalyzes the transfer of an acetyl group from acetyl-CoA to the sn-3 position of diacylglycerol to form 3-acetyl-1,2-diacyl-sn-glycerol (acetyl-TAG). EaDAcT belongs to a small, plant-specific subfamily of the membrane bound O-acyltransferases (MBOAT) that acylate different lipid substrates. Sucrose gradient density centrifugation revealed that EaDAcT colocalizes to the same fractions as an endoplasmic reticulum (ER)-specific marker. By mapping the membrane topology of EaDAcT, we obtained an experimentally determined topology model for a plant MBOAT. The EaDAcT model contains four transmembrane domains (TMDs), with both the N- and C-termini orientated toward the lumen of the ER. In addition, there is a large cytoplasmic loop between the first and second TMDs, with the MBOAT signature region of the protein embedded in the third TMD close to the interface between the membrane and the cytoplasm. During topology mapping, we discovered two cysteine residues (C187 and C293) located on opposite sides of the membrane that are important for enzyme activity. In order to identify additional amino acid residues important for acetyltransferase activity, we isolated and characterized acetyltransferases from other acetyl-TAG-producing plants. Among them, the acetyltransferase from Euonymus fortunei possessed the highest activity in vivo and in vitro. Mutagenesis of conserved amino acids revealed that S253, H257, D258 and V263 are essential for EaDAcT activity. Alteration of residues unique to the acetyltransferases did not alter the unique acyl donor specificity of EaDAcT, suggesting that multiple amino acids are important for substrate recognition. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  12. Comparison of dot-ELISA and standard ELISA for detection of Neisseria meningitidis outer membrane complex-specific antibodies

    Directory of Open Access Journals (Sweden)

    Elza FT Belo

    Full Text Available Dot-ELISA using the outer membrane complex antigens of Neisseria meningitidis as a target was standardized for rapid detection of meningococcal-specific antibodies in human serum. We investigated the level of meningococcal-specific IgG, IgA, and IgM in serum using dot-ELISA with outer membrane antigens prepared from Neisseria meningitidis serotype B:4.19:P1.15,3,7,9 (a strain isolated from a Brazilian epidemic. The dot-ELISA is based on the same principles as the standard ELISA and is useful for detection of anti-N. meningitidis B antibodies in serum of patients with meningococcal infections. For the assay, outer membrane complexes (OMCs were absorbed by nitrocellulose membrane and blocked with a 5% skim milk solution. Serum samples were drawn upon hospital admission and during convalescence from patients with meningococcal septicemia, and single samples were drawn from uninfected controls. We retrospectively examined a total of 57 serum samples: 35 from patients infected with N. meningitidis B, 12 from patients infected with Haemophilus influenzae b, and 10 from health individuals. When performed at room temperature, dot-ELISA took approximately four hours to perform, and the optimum antigen concentration was 0.42 µg per dot. The specificity of IgG, IgM, and IgA demonstrates that dot-ELISA using OMCs from N. meningitidis B as a target is suitable for serologic verification of clinically suspected meningococcal disease in patients and for titer determination of antibodies produced during different phases of natural infection. Furthermore, the sensitivity of dot-ELISA was comparable to that of standard ELISA. Overall, dot-ELISA is simple to perform, rapid, and low cost. Further validation of the test as a screening tool is required.

  13. Reproductive organ and vascular specific promoter of the rice plasma membrane Ca2+ATPase mediates environmental stress responses in plants.

    Directory of Open Access Journals (Sweden)

    Kazi Md Kamrul Huda

    Full Text Available Plasma membrane Ca(2+ATPase is a transport protein in the plasma membrane of cells and helps in removal of calcium (Ca(2+ from the cell, hence regulating Ca(2+ level within cells. Though plant Ca(2+ATPases have been shown to be involved in plant stress responses but their promoter regions have not been well studied.The 1478 bp promoter sequence of rice plasma membrane Ca(2+ATPase contains cis-acting elements responsive to stresses and plant hormones. To identify the functional region, serial deletions of the promoter were fused with the GUS sequence and four constructs were obtained. These were differentially activated under NaCl, PEG cold, methyl viologen, abscisic acid and methyl jasmonate treatments. We demonstrated that the rice plasma membrane Ca(2+ATPase promoter is responsible for vascular-specific and multiple stress-inducible gene expression. Only full-length promoter showed specific GUS expression under stress conditions in floral parts. High GUS activity was observed in roots with all the promoter constructs. The -1478 to -886 bp flanking region responded well upon treatment with salt and drought. Only the full-length promoter presented cold-induced GUS expression in leaves, while in shoots slight expression was observed for -1210 and -886 bp flanking region. The -1210 bp deletion significantly responded to exogenous methyl viologen and abscisic acid induction. The -1210 and -886 bp flanking region resulted in increased GUS activity in leaves under methyl jasmonate treatments, whereas in shoots the -886 bp and -519 bp deletion gave higher expression. Salicylic acid failed to induce GUS activities in leaves for all the constructs.The rice plasma membrane Ca(2+ATPase promoter is a reproductive organ-specific as well as vascular-specific. This promoter contains drought, salt, cold, methyl viologen, abscisic acid and methyl jasmonate related cis-elements, which regulated gene expression. Overall, the tissue-specificity and inducible

  14. Substrate Specificity, Membrane Topology, and Activity Regulation of Human Alkaline Ceramidase 2 (ACER2)*

    OpenAIRE

    Sun, Wei; Jin, Junfei; Xu, Ruijuan; Hu, Wei; Szulc, Zdzislaw M.; Bielawski, Jacek; Obeid, Lina M.; Mao, Cungui

    2010-01-01

    Human alkaline ceramidase 2 (ACER2) plays an important role in cellular responses by regulating the hydrolysis of ceramides in cells. Here we report its biochemical characterization, membrane topology, and activity regulation. Recombinant ACER2 was expressed in yeast mutant cells (Δypc1Δydc1) that lack endogenous ceramidase activity, and microsomes from ACER2-expressiong yeast cells were used to biochemically characterize ACER2. ACER2 catalyzed the hydrolysis of various ceramides and followed...

  15. Prostate-specific membrane antigen (PSMA)-mediated laminin proteolysis generates a pro-angiogenic peptide

    Czech Academy of Sciences Publication Activity Database

    Conway, R. E.; Rojas, C.; Alt, J.; Nováková, Zora; Richardson, S. M.; Rodrick, T. C.; Fuentes, J. L.; Richardson, N. H.; Attalla, J.; Stewart, S.; Fahmy, B.; Bařinka, Cyril; Ghosh, M.; Shapiro, L. H.; Slusher, B. S.

    2016-01-01

    Roč. 19, č. 4 (2016), s. 487-500 ISSN 0969-6970 R&D Projects: GA ČR GAP301/12/1513; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:86652036 Keywords : TUMOR-ASSOCIATED NEOVASCULATURE * BASEMENT-MEMBRANE * DISTINCT ANTITUMOR PROPERTIES Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 5.253, year: 2016

  16. Specific binding of a fungal glucan phytoalexin elicitor to membrane fractions from soybean Glycine max

    International Nuclear Information System (INIS)

    Schmidt, W.E.; Ebel, J.

    1987-01-01

    Treatment of soybean tissues with elicitors results in the production of phytoalexins, one of a number of inducible plant defense reactions against microbial infections. The present study uses a β-1,3-[ 3 H] glucan elicitor fraction from Phytophthora megasperma f.sp. glycinea, a fungal pathogen of soybean, to identify putative elicitor targets in soybean tissues. Use of the radiolabeled elicitor disclosed saturable high-affinity elicitor binding site(s) in membrane fractions of soybean roots. Highest binding activity is associated with a plasma membrane-enriched fraction. The apparent K/sub d/ value for β-glucan elicitor binding is ≅ 0.2 x 10 -6 M and the maximum number of binding sites is 0.5 pmol per mg of protein. Competition studies the [ 3 H]glucan elicitor and a number of polysaccharides demonstrate that only polysaccharides of a branched β-glucan type effectively displace the radiolabeled ligand from membrane binding. Differential displacing activity of the glucans on P. megasperma elicitor binding corresponds closely to their respective ability to elicit phytoalexin production in a cotyledon bioassay

  17. Plasma membrane associated, virus-specific polypeptides required for the formation of target antigen complexes recognized by virus-specific cytotoxic T lymphocytes

    International Nuclear Information System (INIS)

    Domber, E.A.

    1986-01-01

    These studies were undertaken to define some of the poxvirus-specific target antigens which are synthesized in infected cells and recognized by vaccinia virus-specific CTLs (VV-CTLs). Since vaccinia virus infected, unmanipulated target cells express numerous virus-specific antigens on the plasma membrane, attempts were made to manipulate expression of the poxvirus genome after infection so that one or a few defined virus-specified antigens were expressed on the surface of infected cells. In vitro [ 51 Cr]-release assays determined that viral DNA synthesis and expression of late viral proteins were not necessary to form a target cell which was fully competent for lysis by VV-CTLs. Under the conditions employed in these experiments, 90-120 minutes of viral protein synthesis were necessary to produce a competent cell for lysis by VV-CTLs. In order to further inhibit the expression of early viral proteins in infected cells, partially UV-inactivated vaccinia virus was employed to infect target cells. It was determined that L-cells infected with virus preparations which had been UV-irradiated for 90 seconds were fully competent for lysis by VV-CTLs. Cells infected with 90 second UV-irr virus expressed 3 predominant, plasma membrane associated antigens of 36-37K, 27-28K, and 19-17K. These 3 viral antigens represent the predominant membrane-associated viral antigens available for interaction with class I, major histocompatibility antigens and hence are potential target antigens for VV-CTLs

  18. Human lactoferricin derived di-peptides deploying loop structures induce apoptosis specifically in cancer cells through targeting membranous phosphatidylserine.

    Science.gov (United States)

    Riedl, Sabrina; Leber, Regina; Rinner, Beate; Schaider, Helmut; Lohner, Karl; Zweytick, Dagmar

    2015-11-01

    Host defense-derived peptides have emerged as a novel strategy for the development of alternative anticancer therapies. In this study we report on characteristic features of human lactoferricin (hLFcin) derivatives which facilitate specific killing of cancer cells of melanoma, glioblastoma and rhabdomyosarcoma compared with non-specific derivatives and the synthetic peptide RW-AH. Changes in amino acid sequence of hLFcin providing 9-11 amino acids stretched derivatives LF11-316, -318 and -322 only yielded low antitumor activity. However, the addition of the repeat (di-peptide) and the retro-repeat (di-retro-peptide) sequences highly improved cancer cell toxicity up to 100% at 20 μM peptide concentration. Compared to the complete parent sequence hLFcin the derivatives showed toxicity on the melanoma cell line A375 increased by 10-fold and on the glioblastoma cell line U-87mg by 2-3-fold. Reduced killing velocity, apoptotic blebbing, activation of caspase 3/7 and formation of apoptotic DNA fragments proved that the active and cancer selective peptides, e.g. R-DIM-P-LF11-322, trigger apoptosis, whereas highly active, though non-selective peptides, such as DIM-LF11-318 and RW-AH seem to kill rapidly via necrosis inducing membrane lyses. Structural studies revealed specific toxicity on cancer cells by peptide derivatives with loop structures, whereas non-specific peptides comprised α-helical structures without loop. Model studies with the cancer membrane mimic phosphatidylserine (PS) gave strong evidence that PS only exposed by cancer cells is an important target for specific hLFcin derivatives. Other negatively charged membrane exposed molecules as sialic acid, heparan and chondroitin sulfate were shown to have minor impact on peptide activity. Copyright © 2015. Published by Elsevier B.V.

  19. Calcium and Magnesium Ions Are Membrane-Active against Stationary-Phase Staphylococcus aureus with High Specificity

    Science.gov (United States)

    Xie, Yuntao; Yang, Lihua

    2016-02-01

    Staphylococcus aureus (S. aureus) is notorious for its ability to acquire antibiotic-resistance, and antibiotic-resistant S. aureus has become a wide-spread cause of high mortality rate. Novel antimicrobials capable of eradicating S. aureus cells including antibiotic-resistant ones are thus highly desired. Membrane-active bactericides and species-specific antimicrobials are two promising sources of novel anti-infective agents for fighting against bacterial antibiotic-resistance. We herein show that Ca2+ and Mg2+, two alkaline-earth-metal ions physiologically essential for diverse living organisms, both disrupt model S. aureus membranes and kill stationary-phase S. aureus cells, indicative of membrane-activity. In contrast to S. aureus, Escherichia coli and Bacillus subtilis exhibit unaffected survival after similar treatment with these two cations, indicative of species-specific activity against S. aureus. Moreover, neither Ca2+ nor Mg2+ lyses mouse red blood cells, indicative of hemo-compatibility. This works suggests that Ca2+ and Mg2+ may have implications in targeted eradication of S. aureus pathogen including the antibiotic-resistant ones.

  20. Specific binding of prostaglandin E2 to membrane preparations from human skin: receptor modulation by UVB-irradiation and chemical agents

    International Nuclear Information System (INIS)

    Lord, J.T.; Ziboh, V.A.

    1979-01-01

    Human skin membranes bind prostaglandin E2 (PGE2) with high affinity and specificity. This binding is inhibited by trypsin or heat treatment suggesting that PGE2 receptors have protein components. Exposure of the membranes to ultraviolet irradiation (UVB) resulted in the loss of the membrane binding capacity for PGE2. This UVB-inhibitory effect could be prevented by a known protein sulfhydryl-oxidizing agent and a known lipid anti-oxidant

  1. Determination of the secondary energy from the electron beam with a flattening foil by computer. Percentage depth dose curve fitting using the specific higher order polynomial

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, H [Kyushu Univ., Beppu, Oita (Japan). Inst. of Balneotherapeutics

    1980-09-01

    A computer program written in FORTRAN is described for determining the secondary energy of the electron beam which passed through a flattening foil, using a time-sharing computer service. The procedure of this program is first to fit the specific higher order polynomial to the measured percentage depth dose curve. Next, the practical range is evaluated by the point of intersection R of the line tangent to the fitted curve at the inflection point P and the given dose E, as shown in Fig. 2. Finally, the secondary energy corresponded to the determined practical range can be obtained by the experimental equation (2.1) between the practial range R (g/cm/sup 2/) and the electron energy T (MeV). A graph for the fitted polynomial with the inflection points and the practical range can be plotted on a teletype machine by request of user. In order to estimate the shapes of percentage depth dose curves correspond to the electron beams of different energies, we tried to find some specific functional relationships between each coefficient of the fitted seventh-degree equation and the incident electron energies. However, exact relationships could not be obtained for irreguarity among these coefficients.

  2. Electron paramagnetic resonance spin label titration: a novel method to investigate random and site-specific immobilization of enzymes onto polymeric membranes with different properties

    International Nuclear Information System (INIS)

    Butterfield, D. Allan; Colvin, Joshua; Liu Jiangling; Wang Jianquan; Bachas, Leonidas; Bhattacharrya, Dibakar

    2002-01-01

    The immobilization of biological molecules onto polymeric membranes to produce biofunctional membranes is used for selective catalysis, separation, analysis, and artificial organs. Normally, random immobilization of enzymes onto polymeric membranes leads to dramatic reduction in activity due to chemical reactions involved in enzyme immobilization, multiple-point binding, etc., and the extent of activity reduction is a function of membrane hydrophilicity (e.g. activity in cellulosic membrane >> polysulfone membrane). We have used molecular biology to effect site-specific immobilization of enzymes in a manner that orients the active site away from the polymeric membrane surface, thus resulting in higher enzyme activity that approaches that in solution and in increased stability of the enzyme relative to the enzyme in solution. A prediction of this site-specific method of enzyme immobilization, which in this study with subtilisin and organophosphorus hydrolase consists of a fusion tag genetically added to these enzymes and subsequent immobilization via the anti-tag antibody and membrane-bound protein A, is that the active site conformation will more closely resemble that of the enzyme in solution than is the case for random immobilization. This hypothesis was confirmed using a new electron paramagnetic resonance (EPR) spin label active site titration method that determines the amount of spin label bound to the active site of the immobilized enzyme. This value nearly perfectly matched the enzyme activity, and the results suggested: (a) a spectroscopic method for measuring activity and thus the extent of active enzyme immobilization in membrane, which may have advantages in cases where optical methods can not be used due to light scattering interference; (b) higher spin label incorporation (and hence activity) in enzymes that had been site-specifically immobilized versus random immobilization; (c) higher spin label incorporation in enzymes immobilized onto hydrophilic

  3. A comparison of conventional maximum intensity projection with a new depth-specific topographic mapping technique in the CT analysis of proximal tibial subchondral bone density

    International Nuclear Information System (INIS)

    Johnston, James D.; Kontulainen, Saija A.; Masri, Bassam A.; Wilson, David R.

    2010-01-01

    The objective was to identify subchondral bone density differences between normal and osteoarthritic (OA) proximal tibiae using computed tomography osteoabsorptiometry (CT-OAM) and computed tomography topographic mapping of subchondral density (CT-TOMASD). Sixteen intact cadaver knees from ten donors (8 male:2 female; mean age:77.8, SD:7.4 years) were categorized as normal (n = 10) or OA (n = 6) based upon CT reconstructions. CT-OAM assessed maximum subchondral bone mineral density (BMD). CT-TOMASD assessed average subchondral BMD across three layers (0-2.5, 2.5-5 and 5-10 mm) measured in relation to depth from the subchondral surface. Regional analyses of CT-OAM and CT-TOMASD included: medial BMD, lateral BMD, and average BMD of a 10-mm diameter area that searched each medial and lateral plateau for the highest ''focal'' density present within each knee. Compared with normal knees, both CT-OAM and CT-TOMASD demonstrated an average of 17% greater whole medial compartment density in OA knees (p 0.05). CT-TOMASD focal region analyses revealed an average of 24% greater density in the 0- to 2.5-mm layer (p = 0.003) and 36% greater density in the 2.5- to 5-mm layer (p = 0.034) in OA knees. Both CT-OAM and TOMASD identified higher medial compartment density in OA tibiae compared with normal tibiae. In addition, CT-TOMASD indicated greater focal density differences between normal and OA knees with increased depth from the subchondral surface. Depth-specific density analyses may help identify and quantify small changes in subchondral BMD associated with OA disease onset and progression. (orig.)

  4. [New Radiopharmaceuticals Based on Prostate-Specific Inhibitors of Membrane Antigen for Diagnostics and Therapy of Metastatic Prostate Cancer].

    Science.gov (United States)

    Vlasova, O P; German, K E; Krilov, V V; Petriev, V M; Epstein, N B

    2015-01-01

    About 10.7% cases of prostate cancer were registered in Russia in 2011 (40,000 patients). More than half of cancer cases were revealed in advanced (III-IV) stages when metastases inevitably developed quickly. Clinical problem of early diagnostics and treatment of metastatic prostate cancer is still not solved. Anatomical imaging techniques have low sensitivity and specificity for the detection of this disease. Metabolic visualization methods which use prostate specific antigen (PSA) as a marker are also ineffective. This article describes prostate-specific membrane antigens (PSMA) that are proposed as a marker for diagnostics and therapy of prostate cancer. The most promising PSMA-based radiopharmaceutical agent for diagnostics has been developed and clinically tested in the European countries. These pharmaceuticals are based on small peptide molecules modified with urea, and have the highest affinity to PSMA. Favorable phannacokinetics, rapid accumulation in the tumor and rapid excretion from the body are beneficial features of these pharmaceuticals.

  5. The Specific Features of Red Blood Cell Membranes in Premature Neonates Due to Multiple Pregnancy

    Directory of Open Access Journals (Sweden)

    S. A. Perepelitsa

    2014-01-01

    Full Text Available Objective: to substantiate the efficacy of bipolar impulses of different shapes and duration.Method. The investigation used the dynamic model II of the mammalian ventricular cardiomyocyte membrane in the guinea-pig, proposed by Luo and Rudy (1994—2000. The cardiomyocyte membrane was acted by substituting the current density of the impulse under study. The threshold impulse energy ratio considered as an integral index of the threshold action (a measure of efficiency of an impulse measured in μA2 ms/cm4 was then calculated. A comparison was made between a classical quasimembrane, the most effective impulses are quasi

  6. Is the C-terminal insertional signal in Gram-negative bacterial outer membrane proteins species-specific or not?

    Directory of Open Access Journals (Sweden)

    Paramasivam Nagarajan

    2012-09-01

    Full Text Available Abstract Background In Gram-negative bacteria, the outer membrane is composed of an asymmetric lipid bilayer of phopspholipids and lipopolysaccharides, and the transmembrane proteins that reside in this membrane are almost exclusively β-barrel proteins. These proteins are inserted into the membrane by a highly conserved and essential machinery, the BAM complex. It recognizes its substrates, unfolded outer membrane proteins (OMPs, through a C-terminal motif that has been speculated to be species-specific, based on theoretical and experimental results from only two species, Escherichia coli and Neisseria meningitidis, where it was shown on the basis of individual sequences and motifs that OMPs from the one cannot easily be over expressed in the other, unless the C-terminal motif was adapted. In order to determine whether this species specificity is a general phenomenon, we undertook a large-scale bioinformatics study on all predicted OMPs from 437 fully sequenced proteobacterial strains. Results We were able to verify the incompatibility reported between Escherichia coli and Neisseria meningitidis, using clustering techniques based on the pairwise Hellinger distance between sequence spaces for the C-terminal motifs of individual organisms. We noticed that the amino acid position reported to be responsible for this incompatibility between Escherichia coli and Neisseria meningitidis does not play a major role for determining species specificity of OMP recognition by the BAM complex. Instead, we found that the signal is more diffuse, and that for most organism pairs, the difference between the signals is hard to detect. Notable exceptions are the Neisseriales, and Helicobacter spp. For both of these organism groups, we describe the specific sequence requirements that are at the basis of the observed difference. Conclusions Based on the finding that the differences between the recognition motifs of almost all organisms are small, we assume that

  7. Thrombus imaging in a primate model with antibodies specific for an external membrane protein of activated platelets

    International Nuclear Information System (INIS)

    Palabrica, T.M.; Furie, B.C.; Konstam, M.A.; Aronovitz, M.J.; Connolly, R.; Brockway, B.A.; Ramberg, K.L.; Furie, B.

    1989-01-01

    The activated platelet is a potential target for the localization of thrombi in vivo since, after stimulation and secretion of granule contents, activated platelets are concentrated at sites of blood clot formation. In this study, we used antibodies specific for a membrane protein of activated platelets to detect experimental thrombi in an animal model. PADGEM (platelet activation-dependent granule-external membrane protein), a platelet alpha-granule membrane protein, is translocated to the plasma membrane during platelet activation and granule secretion. Since PADGEM is internal in unstimulated platelets, polyclonal anti-PADGEM and monoclonal KC4 antibodies do not bind to circulating resting platelets but do interact with activated platelets. Dacron graft material incubated with radiolabeled KC4 or anti-PADGEM antibodies in the presence of thrombin-activated platelet-rich plasma bound most of the antibody. Imaging experiments with 123I-labeled anti-PADGEM in baboons with an external arterial-venous Dacron shunt revealed rapid uptake in the thrombus induced by the Dacron graft; control experiments with 123I-labeled nonimmune IgG exhibited minimal uptake. Deep venous thrombi, formed by using percutaneous balloon catheters to stop blood flow in the femoral vein of baboons, were visualized with 123I-labeled anti-PADGEM. Thrombi were discernible against blood pool background activity without subtraction techniques within 1 hr. No target enhancement was seen with 123I-labeled nonimmune IgG. 123I-labeled anti-PADGEM cleared the blood pool with an initial half-disappearance time of 6 min and did not interfere with hemostasis. These results indicate that radioimmunoscintigraphy with anti-PADGEM antibodies can visualize thrombi in baboon models and is a promising technique for clinical thrombus detection in humans

  8. Effects of deuterated water upon specific activity of some marker enzymes for cytosol and plasmatic membrane

    International Nuclear Information System (INIS)

    Buzgariu, Wanda; Coroiu, Viorica; Moldovan, Lucia; Titescu, G.; Stefanescu, I.

    2004-01-01

    Recently, numerous studies were devoted to the effects of an increased environmental deuterium concentration on physiological characteristics of various biological systems, from monocellular organisms up to mammals. Within these preoccupations the experiments on enzyme activity and parameters are of special interest since they throw light upon the mechanisms in metabolic biochemical reactions (glycolysis, photosynthesis, transport across membranes, etc). The present work concerns the effects of heavy water upon the activity of some enzymes (dehydrogenase-LDH lactate and 5' nucleotidase) implied in different metabolic pathways, serving as functional indicators for some cellular compartments such as the cytosols and cellular membranes. Enzyme activity was determined by growing for 6 days the cells (Hep 2, CHO, fibroblasts) in deuterated culture media at different concentration levels (20%, 40%, 65% si 90%), as well as in a reaction medium deuterated at 99.96%. In case of the first experimental run the LDH activity was monitored for the three cellular lines (Hep 2, CHO, fibroblasts) for different time intervals (1 d, 3 d and 6 d). After the first 24 h of cells' exposure the activity values were similar regardless of the heavy water concentration in the medium. Exposing the cells for longer time (6 days) led to modifications of LDH activity. In contrast to the case of media with relatively moderate D 2 O content, cell growing in conditions of intense deuteration 65% and 90 % D 2 O) led to an increase of cytosolic enzyme activity of about 50%. In case of 5' nucleotidase after 6 days of cell cultivation in deuteration conditions the activity decreased to 50% and 70% from the value corresponding to normal conditions for cell growth. This diminution of the activity was characteristic for the media with 65% and 90% D 2 O. In the second experimental run the activities of dehydrogenase lactate and 5' nucleotidase from the cellular homogenate obtained from cells grown in

  9. Specific and efficient targeting of cyanobacterial bicarbonate transporters to the inner envelope membrane of chloroplasts in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Susumu eUehara

    2016-02-01

    Full Text Available Installation of cyanobacterial bicarbonate transporters to the inner envelope membrane (IEM of chloroplasts in C3 plants has been thought to improve photosynthetic performance. However, the method to deliver cyanobacterial bicarbonate transporters to the chloroplast IEM remains to be established. In this study, we provide evidence that the cyanobacterial bicarbonate transporters, BicA and SbtA, can be specifically installed into the chloroplast IEM using the chloroplast IEM targeting signal in conjunction with the transit peptide. We fused the transit peptide and the mature portion of Cor413im1, whose targeting mechanism to the IEM has been characterized in detail, to either BicA or SbtA isolated from Synechocystis sp. PCC6803. Among the seven chimeric constructs tested, we confirmed that four chimeric bicarbonate transporters, designated as BicAI, BicAII, SbtAII, and SbtAIII, were expressed in Arabidopsis. Furthermore, these chimeric transporters were specifically targeted to the chloroplast IEM. They were also resistant to alkaline extraction but can be solubilized by Triton X-100, indicating that they are integral membrane proteins in the chloroplast IEM. One of the transporters, BicA, could reside in the chloroplast IEM even after removal of the IEM targeting signal. Taken together, our results indicate that the addition of IEM targeting signal, as well as the transit peptide, to bicarbonate transporters allows us to efficiently target nuclear-encoded chimeric bicarbonate transporters to the chloroplast IEM.

  10. Undressing of Waddlia chondrophila to enrich its outer membrane proteins to develop a new species-specific ELISA

    Directory of Open Access Journals (Sweden)

    J. Lienard

    2014-01-01

    Full Text Available Waddlia chondrophila, an obligate intracellular bacterium of the Chlamydiales order, is considered as an agent of bovine abortion and a likely cause of miscarriage in humans. Its role in respiratory diseases was questioned after the detection of its DNA in clinical samples taken from patients suffering from pneumonia or bronchiolitis. To better define the role of Waddlia in both miscarriage and pneumonia, a tool allowing large-scale serological investigations of Waddlia seropositivity is needed. Therefore, enriched outer membrane proteins of W. chondrophila were used as antigens to develop a specific ELISA. After thorough analytical optimization, the ELISA was validated by comparison with micro-immunofluorescence and it showed a sensitivity above 85% with 100% specificity. The ELISA was subsequently applied to human sera to specify the role of W. chondrophila in pneumonia. Overall, 3.6% of children showed antibody reactivity against W. chondrophila but no significant difference was observed between children with and without pneumonia. Proteomic analyses were then performed using mass spectrometry, highlighting members of the outer membrane protein family as the dominant proteins. The major Waddlia putative immunogenic proteins were identified by immunoblot using positive and negative human sera. The new ELISA represents an efficient tool with high throughput applications. Although no association with pneumonia and Waddlia seropositivity was observed, this ELISA could be used to specify the role of W. chondrophila in miscarriage and in other diseases.

  11. A distance measurement between specific sites on the cytoplasmic surface of bovine rhodopsin in rod outer segment disk membranes.

    Science.gov (United States)

    Albert, A D; Watts, A; Spooner, P; Groebner, G; Young, J; Yeagle, P L

    1997-08-14

    Structural information on mammalian integral membrane proteins is scarce. As part of work on an alternative approach to the structure of bovine rhodopsin, a method was devised to obtain an intramolecular distance between two specific sites on rhodopsin while in the rod outer segment disk membrane. In this report, the distance between the rhodopsin kinase phosphorylation site(s) on the carboxyl terminal and the top of the third transmembrane helix was measured on native rhodopsin. Rhodopsin was labeled with a nuclear spin label (31P) by limited phosphorylation with rhodopsin kinase. Major phosphorylation occurs at serines 343 and 338 on the carboxyl terminal. The phosphorylated rhodopsin was then specifically labeled on cysteine 140 with an electron spin label. Magic angle spinning 31P-nuclear magnetic resonance revealed the resonance arising from the phosphorylated protein. The enhancement of the transverse relaxation of this resonance by the paramagnetic spin label was observed. The strength of this perturbation was used to determine the through-space distance between the phosphorylation site(s) and the spin label position. A distance of 18 +/- 3 A was obtained.

  12. Cloning of B cell-specific membrane tetraspanning molecule BTS possessing B cell proliferation-inhibitory function.

    Science.gov (United States)

    Suenaga, Tadahiro; Arase, Hisashi; Yamasaki, Sho; Kohno, Masayuki; Yokosuka, Tadashi; Takeuchi, Arata; Hattori, Takamichi; Saito, Takashi

    2007-11-01

    Lymphocyte proliferation is regulated by signals through antigen receptors, co-stimulatory receptors, and other positive and negative modulators. Several membrane tetraspanning molecules are also involved in the regulation of lymphocyte growth and death. We cloned a new B cell-specific tetraspanning (BTS) membrane molecule, which is similar to CD20 in terms of expression, structure and function. BTS is specifically expressed in the B cell line and its expression is increased after the pre-B cell stage. BTS is expressed in intracellular granules and on the cell surface. Overexpression of BTS in immature B cell lines induces growth retardation through inhibition of cell cycle progression and cell size increase without inducing apoptosis. This inhibitory function is mediated predominantly by the N terminus of BTS. The development of mature B cells is inhibited in transgenic mice expressing BTS, suggesting that BTS is involved in the in vivo regulation of B cells. These results indicate that BTS plays a role in the regulation of cell division and B cell growth.

  13. Effect of long-term propranolol administration on specific binding of 3H-WB-4101 with rat mesenteric vascular membranes

    International Nuclear Information System (INIS)

    Ismailov, S.I.; Rozhanets, V.V.; Val'dman, A.V.

    1985-01-01

    The aim of this investigation was, first, to study the affinity of certain beta-adrenoblockers for specific binding sites of 3 H-WB-4101 (identifiable as alpha-adrenoreceptors) of brain membranes and, second, to study the characteristics of these same receptors in membranes of mesenteric vessels of rats during long-term administration of propranolol. Isotherms of specific binding, because of the limited quantity of vascular membranes, were determined by the use of three concentrations of 3 H-WB-4101: 0.1, 0.5, and 1.0 nM. It is shown that some beta-adrenoblockers have weak affinity for alpha-adrenoreceptors of brain synaptic membranes exhibited only when these compounds are present in relatively high concentrations. It is also shown that administration of propranolol for 15 days led to a significant decrease in affinity of the alpha-adrenorecptors for their specific antagonist WB-4101

  14. The N-terminal amphipathic helix of the topological specificity factor MinE is associated with shaping membrane curvature.

    Directory of Open Access Journals (Sweden)

    Yu-Ling Shih

    Full Text Available Pole-to-pole oscillations of the Min proteins in Escherichia coli are required for the proper placement of the division septum. Direct interaction of MinE with the cell membrane is critical for the dynamic behavior of the Min system. In vitro, this MinE-membrane interaction led to membrane deformation; however, the underlying mechanism remained unclear. Here we report that MinE-induced membrane deformation involves the formation of an amphipathic helix of MinE(2-9, which, together with the adjacent basic residues, function as membrane anchors. Biochemical evidence suggested that the membrane association induces formation of the helix, with the helical face, consisting of A2, L3, and F6, inserted into the membrane. Insertion of this helix into the cell membrane can influence local membrane curvature and lead to drastic changes in membrane topology. Accordingly, MinE showed characteristic features of protein-induced membrane tubulation and lipid clustering in in vitro reconstituted systems. In conclusion, MinE shares common protein signatures with a group of membrane trafficking proteins in eukaryotic cells. These MinE signatures appear to affect membrane curvature.

  15. In-depth analyses of organic matters in a full-scale seawater desalination plant and an autopsy of reverse osmosis membrane

    KAUST Repository

    Jeong, Sanghyun; Naidu, Gayathri; Vollprecht, Robert; Leiknes, TorOve; Vigneswaran, Saravanamuthu

    2016-01-01

    In order to facilitate the global performance of seawater reverse osmosis (SWRO) systems, it is important to improve the feed water quality before it enters the RO. Currently, many desalination plants experience production losses due to incidents of organic and biofouling. Consequently, monitoring or characterizing the pretreatment step using more advanced organic and biological parameters are required for better operation to lessen fouling issues. In this study, the performance of pretreatment processes (including coagulation, dual media filtration (DMF), polishing with cartridge filter (CF) coupled with anti-scalant) used at Perth Seawater Desalination Plant (PSDP) located in Western Australia were characterized in terms of organic and biological fouling parameters. These analyses were carried out using liquid chromatography with organic carbon detector (LC-OCD), three dimensional-fluorescence excitation emission matrix (3D-FEEM) and assimilable organic carbon (AOC). Furthermore, the used (exhausted) RO membrane and CF were autopsied so that the fates and behaviors of organic foulants in these treatment systems could be better understood.

  16. In-depth analyses of organic matters in a full-scale seawater desalination plant and an autopsy of reverse osmosis membrane

    KAUST Repository

    Jeong, Sanghyun

    2016-02-17

    In order to facilitate the global performance of seawater reverse osmosis (SWRO) systems, it is important to improve the feed water quality before it enters the RO. Currently, many desalination plants experience production losses due to incidents of organic and biofouling. Consequently, monitoring or characterizing the pretreatment step using more advanced organic and biological parameters are required for better operation to lessen fouling issues. In this study, the performance of pretreatment processes (including coagulation, dual media filtration (DMF), polishing with cartridge filter (CF) coupled with anti-scalant) used at Perth Seawater Desalination Plant (PSDP) located in Western Australia were characterized in terms of organic and biological fouling parameters. These analyses were carried out using liquid chromatography with organic carbon detector (LC-OCD), three dimensional-fluorescence excitation emission matrix (3D-FEEM) and assimilable organic carbon (AOC). Furthermore, the used (exhausted) RO membrane and CF were autopsied so that the fates and behaviors of organic foulants in these treatment systems could be better understood.

  17. Prostate-specific membrane antigen PET/MRI validation of MR textural analysis for detection of transition zone prostate cancer.

    Science.gov (United States)

    Bates, Anthony; Miles, Kenneth

    2017-12-01

    To validate MR textural analysis (MRTA) for detection of transition zone (TZ) prostate cancer through comparison with co-registered prostate-specific membrane antigen (PSMA) PET-MR. Retrospective analysis was performed for 30 men who underwent simultaneous PSMA PET-MR imaging for staging of prostate cancer. Thirty texture features were derived from each manually contoured T2-weighted, transaxial, prostatic TZ using texture analysis software that applies a spatial band-pass filter and quantifies texture through histogram analysis. Texture features of the TZ were compared to PSMA expression on the corresponding PET images. The Benjamini-Hochberg correction controlled the false discovery rate at prostate cancer. • Prostate transition zone (TZ) MR texture analysis may assist in prostate cancer detection. • Abnormal transition zone PSMA expression correlates with altered texture on T2-weighted MR. • TZ with abnormal PSMA expression demonstrates significantly reduced MI, SD and MPP.

  18. In-Depth N-Glycosylation Reveals Species-Specific Modifications and Functions of the Royal Jelly Protein from Western (Apis mellifera) and Eastern Honeybees (Apis cerana).

    Science.gov (United States)

    Feng, Mao; Fang, Yu; Han, Bin; Xu, Xiang; Fan, Pei; Hao, Yue; Qi, Yuping; Hu, Han; Huo, Xinmei; Meng, Lifeng; Wu, Bin; Li, Jianke

    2015-12-04

    Royal jelly (RJ), secreted by honeybee workers, plays diverse roles as nutrients and defense agents for honeybee biology and human health. Despite being reported to be glycoproteins, the glycosylation characterization and functionality of RJ proteins in different honeybee species are largely unknown. An in-depth N-glycoproteome analysis and functional assay of RJ produced by Apis mellifera lingustica (Aml) and Apis cerana cerana (Acc) were conducted. RJ produced by Aml yielded 80 nonredundant N-glycoproteins carrying 190 glycosites, of which 23 novel proteins harboring 35 glycosites were identified. For Acc, all 43 proteins glycosylated at 138 glycosites were reported for the first time. Proteins with distinct N-glycoproteomic characteristics in terms of glycoprotein species, number of N-glycosylated sites, glycosylation motif, abundance level of glycoproteins, and N-glycosites were observed in this two RJ samples. The fact that the low inhibitory efficiency of N-glycosylated major royal jelly protein 2 (MRJP2) against Paenibacillus larvae (P. larvae) and the absence of antibacterial related glycosylated apidaecin, hymenoptaecin, and peritrophic matrix in the Aml RJ compared to Acc reveal the mechanism for why the Aml larvae are susceptible to P. larvae, the causative agent of a fatal brood disease (American foulbrood, AFB). The observed antihypertension activity of N-glycosylated MRJP1 in two RJ samples and a stronger activity found in Acc than in Aml reveal that specific RJ protein and modification are potentially useful for the treatment of hypertensive disease for humans. Our data gain novel understanding that the western and eastern bees have evolved species-specific strategies of glycosylation to fine-tune protein activity for optimizing molecular function as nutrients and immune agents for the good of honeybee and influence on the health promoting activity for human as well. This serves as a valuable resource for the targeted probing of the biological

  19. Love Wave Sensor for Prostate-Specific Membrane Antigen Detection Based on Hydrophilic Molecularly-Imprinted Polymer

    Directory of Open Access Journals (Sweden)

    Pingping Tang

    2018-05-01

    Full Text Available Prostate-specific membrane antigen (PSMA is a biomarker for prostate cancer (PCa, and a specific and reliable detection technique of PSMA is urgently required for PCa early diagnosis. A Love wave sensor has been widely studied for real-time sensing and highly sensitive applications, but the sensing unit needs special handling for selective detection purpose. In this study, we prepared a versatile Love wave sensor functionalized with molecularly-imprinted polymers (MIP, PSMA as the template molecule. To enhance the specific template bindings of MIP in pure aqueous solutions, facile reversible addition/fragmentation chain transfer (RAFT precipitation polymerization (RAFTPP was used to produce surface hydrophilic polymer brushes on MIP. The presence of hydrophilic polymer brushes on MIP improved its surface hydrophilicity and significantly reduced their hydrophobic interactions with template molecules in pure aqueous media. In detection process, the acoustic delay-line is confederative to a microfluidic chip and inserted in an oscillation loop. The real-time resonance frequency of the MIP-based Love wave sensor to different concentrations of PSMA was investigated. The limit of detection (LOD for this Love SAW sensor was 0.013 ng mL−1, which demonstrates that this sensor has outstanding performance in terms of the level of detection.

  20. Detection of nearest neighbors to specific fluorescently tagged ligands in rod outer segment and lymphocyte plasma membranes by photosensitization of 5-iodonaphthyl 1-azide

    International Nuclear Information System (INIS)

    Raviv, Y.; Bercovici, T.; Gitler, C.; Salomon, Y.

    1989-01-01

    Lima bean agglutinin-fluorescein 5-isothiocyanate conjugate (FluNCS-lima bean lectin) interacts with specific receptor molecules on membranes both from the rod outer segment (ROS) of the frog retina and from S49 mouse lymphoma cells. When [125I]-5-iodonaphthyl 1-azide (125I-INA), which freely and randomly partitions into the lipid bilayer, is added to membranes and the suspension is irradiated at 480 nm, the FluNCS-conjugated lectin photosensitizes the [125I]INA but only at discrete sites. This results in the selective labeling of specific proteins: an 88-kDa protein on ROS membranes and a 56-kDa protein on S49 plasma membranes. Labeling is dependent upon the interaction of the FluNCS-lectin with glycosylated receptor sites, since N-acetylgalactosamine, but not methyl alpha-mannoside, blocked labeling of the 56-kDa protein on S49 membranes. In contrast, a random labeling pattern of membrane proteins was observed upon irradiation at 480 nm using other fluorescein conjugates, such as FluNCS-bovine serum albumin (FluNCS-BSA) or FluNCS-soybean trypsin inhibitor (FluNCS-STI), which interact with cell membranes in a nonselective manner, or with N-(fluorescein-5-thiocarbamoyl)-n-undecyclamine (FluNCS-NHC11), which is freely miscible in the membrane lipid. Random labeling was also obtained by direct photoexcitation of [125I]INA at 314 nm, with no distinct labeling of the 88- and 56-kDa proteins in the respective membranes. These results suggest that protein ligands can be used to guide sensitizers to discrete receptor sites and lead to their selective labeling by photosensitized activation of [125I]INA

  1. Phosphatidylinositol 4,5-Bisphosphate (PtdIns(4,5)P2) Specifically Induces Membrane Penetration and Deformation by Bin/Amphiphysin/Rvs (BAR) Domains*

    Science.gov (United States)

    Yoon, Youngdae; Zhang, Xiuqi; Cho, Wonhwa

    2012-01-01

    Cellular proteins containing Bin/amphiphysin/Rvs (BAR) domains play a key role in clathrin-mediated endocytosis. Despite extensive structural and functional studies of BAR domains, it is still unknown how exactly these domains interact with the plasma membrane containing phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and whether they function by a universal mechanism or by different mechanisms. Here we report that PtdIns(4,5)P2 specifically induces partial membrane penetration of the N-terminal amphiphilic α-helix (H0) of two representative N-BAR domains from Drosophila amphiphysin (dAmp-BAR) and rat endophilin A1 (EndoA1-BAR). Our quantitative fluorescence imaging analysis shows that PtdIns(4,5)P2-dependent membrane penetration of H0 is important for self-association of membrane-bound dAmp-BAR and EndoA1-BAR and their membrane deformation activity. EndoA1-BAR behaves differently from dAmp-BAR because the former has an additional amphiphilic α-helix that penetrates the membrane in a PtdIns(4,5)P2-independent manner. Depletion of PtdIns(4,5)P2 from the plasma membrane of HEK293 cells abrogated the membrane deforming activity of EndoA1-BAR and dAmp-BAR. Collectively, these studies suggest that the local PtdIns(4,5)P2 concentration in the plasma membrane may regulate the membrane interaction and deformation by N-BAR domain-containing proteins during clathrin-mediated endocytosis. PMID:22888025

  2. Macoilin, a conserved nervous system-specific ER membrane protein that regulates neuronal excitability.

    Directory of Open Access Journals (Sweden)

    Fausto Arellano-Carbajal

    2011-03-01

    Full Text Available Genome sequence comparisons have highlighted many novel gene families that are conserved across animal phyla but whose biological function is unknown. Here, we functionally characterize a member of one such family, the macoilins. Macoilins are characterized by several highly conserved predicted transmembrane domains towards the N-terminus and by coiled-coil regions C-terminally. They are found throughout Eumetazoa but not in other organisms. Mutants for the single Caenorhabditis elegans macoilin, maco-1, exhibit a constellation of behavioral phenotypes, including defects in aggregation, O₂ responses, and swimming. MACO-1 protein is expressed broadly and specifically in the nervous system and localizes to the rough endoplasmic reticulum; it is excluded from dendrites and axons. Apart from subtle synapse defects, nervous system development appears wild-type in maco-1 mutants. However, maco-1 animals are resistant to the cholinesterase inhibitor aldicarb and sensitive to levamisole, suggesting pre-synaptic defects. Using in vivo imaging, we show that macoilin is required to evoke Ca²(+ transients, at least in some neurons: in maco-1 mutants the O₂-sensing neuron PQR is unable to generate a Ca²(+ response to a rise in O₂. By genetically disrupting neurotransmission, we show that pre-synaptic input is not necessary for PQR to respond to O₂, indicating that the response is mediated by cell-intrinsic sensory transduction and amplification. Disrupting the sodium leak channels NCA-1/NCA-2, or the N-,P/Q,R-type voltage-gated Ca²(+ channels, also fails to disrupt Ca²(+ responses in the PQR cell body to O₂ stimuli. By contrast, mutations in egl-19, which encodes the only Caenorhabditis elegans L-type voltage-gated Ca²(+ channel α1 subunit, recapitulate the Ca²(+ response defect we see in maco-1 mutants, although we do not see defects in localization of EGL-19. Together, our data suggest that macoilin acts in the ER to regulate assembly or

  3. Activated sludge model (ASM) based modelling of membrane bioreactor (MBR) processes: a critical review with special regard to MBR specificities.

    Science.gov (United States)

    Fenu, A; Guglielmi, G; Jimenez, J; Spèrandio, M; Saroj, D; Lesjean, B; Brepols, C; Thoeye, C; Nopens, I

    2010-08-01

    Membrane bioreactors (MBRs) have been increasingly employed for municipal and industrial wastewater treatment in the last decade. The efforts for modelling of such wastewater treatment systems have always targeted either the biological processes (treatment quality target) as well as the various aspects of engineering (cost effective design and operation). The development of Activated Sludge Models (ASM) was an important evolution in the modelling of Conventional Activated Sludge (CAS) processes and their use is now very well established. However, although they were initially developed to describe CAS processes, they have simply been transferred and applied to MBR processes. Recent studies on MBR biological processes have reported several crucial specificities: medium to very high sludge retention times, high mixed liquor concentration, accumulation of soluble microbial products (SMP) rejected by the membrane filtration step, and high aeration rates for scouring purposes. These aspects raise the question as to what extent the ASM framework is applicable to MBR processes. Several studies highlighting some of the aforementioned issues are scattered through the literature. Hence, through a concise and structured overview of the past developments and current state-of-the-art in biological modelling of MBR, this review explores ASM-based modelling applied to MBR processes. The work aims to synthesize previous studies and differentiates between unmodified and modified applications of ASM to MBR. Particular emphasis is placed on influent fractionation, biokinetics, and soluble microbial products (SMPs)/exo-polymeric substances (EPS) modelling, and suggestions are put forward as to good modelling practice with regard to MBR modelling both for end-users and academia. A last section highlights shortcomings and future needs for improved biological modelling of MBR processes. (c) 2010 Elsevier Ltd. All rights reserved.

  4. Anal lymphogranuloma venereum infection screening with IgA anti-Chlamydia trachomatis-specific major outer membrane protein serology.

    Science.gov (United States)

    de Vries, Henry J C; Smelov, Vitaly; Ouburg, Sander; Pleijster, Jolein; Geskus, Ronald B; Speksnijder, Arjen G C L; Fennema, Johannes S A; Morré, Servaas A

    2010-12-01

    Anal lymphogranuloma venereum (LGV) infections, caused by Chlamydia trachomatis biovar L (Ct+/LGV+), are endemic among men who have sex with men (MSM). Anal non-LGV biovar Ct infections (Ct+/LGV-) can be eradicated with 1 week doxycycline, whereas Ct+/LGV+ infections require 3-week doxycycline. To differentiate Ct+/LGV+ from Ct+/LGV- infections, biovar-specific Nucleic Acid Amplification Test (NAAT) are standard, but also expensive and laborious. A chlamydia-specific serological assay could serve as an alternative test. MSM were screened for anal Ct+/LGV+ and Ct+/LGV- infections with a commercial nonspecific NAAT and an in house biovar L-specific NAAT. Serum samples were evaluated with chlamydia-specific anti-Major Outer Membrane Protein (MOMP) and antilipopolysaccharide assays of IgA and IgG classes. Asymptomatic patients were identified as: (1) no anal complaints or (2) no microscopic inflammation (i.e., <10 leucocytes per high power field in anal smears). The best differentiating assay was subsequently evaluated in 100 Ct+/LGV+ and 100 Ct+/LGV- MSM using different cut-off points. The anti-MOMP IgA assay was the most accurate to differentiate Ct+/LGV+ (n = 42) from Ct+/LGV- (n = 19) with 85.7% sensitivity (95% confidence interval [CI], 72.2-93.3) and 84.2% specificity (95% CI, 62.4-94.5), even among asymptomatic patients. In a population comprising 98 Ct+/LGV+ and 105 Ct+/LGV- patients, the anti-MOMP IgA assay scored most accurate when the cut-off point was set to 2.0 with 75.5% (95% CI, 65.8-83.6) sensitivity and 74.3% (95% CI, 64.8-82.3) specificity. The IgA anti-MOMP assay can identify a considerable proportion of the (asymptomatic) anal LGV infections correctly. Yet, biovar L-specific NAAT are still the preferred diagnostic tests in clinical settings.

  5. Rotavirus NSP4114-135 peptide has no direct, specific effect on chloride transport in rabbit brush-border membrane

    Directory of Open Access Journals (Sweden)

    Vasseur Monique

    2006-11-01

    Full Text Available Abstract The direct effect of the rotavirus NSP4114-135 and Norovirus NV464-483 peptides on 36Cl uptake was studied by using villus cell brush border membrane (BBM isolated from young rabbits. Both peptides inhibited the Cl-/H+ symport activity about equally and partially. The interaction involved one peptide-binding site per carrier unit. Whereas in vitro NSP4114-135 caused nonspecific inhibition of the Cl-/H+ symporter, the situation in vivo is different. Because rotavirus infection in young rabbits accelerated both Cl- influx and Cl- efflux rates across villi BBM without stimulating Cl- transport in crypt BBM, we conclude that the NSP4114-135 peptide, which causes diarrhea in young rodents, did not have any direct, specific effect on either intestinal absorption or secretion of chloride. The lack of direct effect of NSP4 on chloride transport strengthens the hypothesis that NSP4 would trigger signal transduction pathways to enhance net chloride secretion at the onset of rotavirus diarrhea.

  6. Pearls and pitfalls in clinical interpretation of prostate-specific membrane antigen (PSMA)-targeted PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sheikhbahaei, Sara; Solnes, Lilja B.; Javadi, Mehrbod S.; Pomper, Martin G.; Rowe, Steven P. [Johns Hopkins University School of Medicine, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Afshar-Oromieh, Ali; Haberkorn, Uwe [Heidelberg University Hospital, Department of Nuclear Medicine, Heidelberg (Germany); Eiber, Matthias [David Geffen School of Medicine at UCLA, Department of Molecular and Medical Pharmacology, Los Angeles, CA (United States); Technical University of Munich, Department of Nuclear Medicine, Klinikum rechts der Isar, Munich (Germany); Ross, Ashley E.; Pienta, Kenneth J.; Allaf, Mohamad E.; Gorin, Michael A. [Johns Hopkins University School of Medicine, The James Buchanan Brady Urological Institute and Department of Urology, Baltimore, MD (United States)

    2017-11-15

    The rapidly expanding clinical adaptation of prostate-specific membrane antigen (PSMA)-targeted PET imaging in the evaluation of patients with prostate cancer has placed an increasing onus on understanding both the potential pearls of interpretation as well as limitations of this new technique. As with any new molecular imaging modality, accurate characterization of abnormalities on PSMA-targeted PET imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants of radiotracer uptake, and potential sources of false-positive and false-negative imaging findings. In recent years, a growing number of reports have come to light describing incidental non-prostatic benign or malignant pathologies with high uptake on PSMA-targeted PET imaging. In this review, we have summarized the published literature regarding the potential pearls and technical and interpretive pitfalls of this imaging modality. Knowledge of these limitations can increase the confidence of interpreting physicians and thus improve patient care. As PSMA-targeted PET is expected to be evaluated in larger prospective trials, the dissemination of potential diagnostic pitfalls and the biologic underpinning of those findings will be of increased importance. (orig.)

  7. The meiosis-specific nuclear passenger protein is required for proper assembly of forespore membrane in fission yeast.

    Science.gov (United States)

    Takaine, Masak; Imada, Kazuki; Numata, Osamu; Nakamura, Taro; Nakano, Kentaro

    2014-10-15

    Sporulation, gametogenesis in yeast, consists of meiotic nuclear division and spore morphogenesis. In the fission yeast Schizosaccharomyces pombe, the four haploid nuclei produced after meiosis II are encapsulated by the forespore membrane (FSM), which is newly synthesized from spindle pole bodies (SPBs) in the cytoplasm of the mother cell as spore precursors. Although the coordination between meiosis and FSM assembly is vital for proper sporulation, the underlying mechanism remains unclear. In the present study, we identified a new meiosis-specific protein Npg1, and found that it was involved in the efficient formation of spores and spore viability. The accumulation and organization of the FSM was compromised in npg1-null cells, leading to the error-prone envelopment of nuclei. Npg1 was first seen as internuclear dots and translocated to the SPBs before the FSM assembled. Genetic analysis revealed that Npg1 worked in conjunction with the FSM proteins Spo3 and Meu14. These results suggest a possible signaling link from the nucleus to the meiotic SPBs in order to associate the onset of FSM assembly with meiosis II, which ensures the successful partitioning of gametic nuclei. © 2014. Published by The Company of Biologists Ltd.

  8. Spatial organization of the cytoskeleton enhances cargo delivery to specific target areas on the plasma membrane of spherical cells

    Science.gov (United States)

    Hafner, Anne E.; Rieger, Heiko

    2016-12-01

    Intracellular transport is vital for the proper functioning and survival of a cell. Cargo (proteins, vesicles, organelles, etc) is transferred from its place of creation to its target locations via molecular motor assisted transport along cytoskeletal filaments. The transport efficiency is strongly affected by the spatial organization of the cytoskeleton, which constitutes an inhomogeneous, complex network. In cells with a centrosome microtubules grow radially from the central microtubule organizing center towards the cell periphery whereas actin filaments form a dense meshwork, the actin cortex, underneath the cell membrane with a broad range of orientations. The emerging ballistic motion along filaments is frequently interrupted due to constricting intersection nodes or cycles of detachment and reattachment processes in the crowded cytoplasm. In order to investigate the efficiency of search strategies established by the cell’s specific spatial organization of the cytoskeleton we formulate a random velocity model with intermittent arrest states. With extensive computer simulations we analyze the dependence of the mean first passage times for narrow escape problems on the structural characteristics of the cytoskeleton, the motor properties and the fraction of time spent in each state. We find that an inhomogeneous architecture with a small width of the actin cortex constitutes an efficient intracellular search strategy.

  9. Spacer length impacts the efficacy of targeted docetaxel conjugates in prostate-specific membrane antigen expressing prostate cancer.

    Science.gov (United States)

    Peng, Zheng-Hong; Sima, Monika; Salama, Mohamed E; Kopečková, Pavla; Kopeček, Jindřich

    2013-12-01

    Combination of targeted delivery and controlled release is a powerful technique for cancer treatment. In this paper, we describe the design, synthesis, structure validation and biological properties of targeted and non-targeted N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-docetaxel conjugates. Docetaxel (DTX) was conjugated to HPMA copolymer via a tetrapeptide spacer (-GFLG-). 3-(1,3-dicarboxypropyl)-ureido]pentanedioic acid (DUPA) was used as the targeting moiety to actively deliver DTX for treatment of Prostate-Specific Membrane Antigen (PSMA) expressing prostate cancer. Short and long spacer DUPA monomers were prepared, and four HPMA copolymer--DTX conjugates (non-targeted, two targeted with short spacer of different molecular weight and targeted with long spacer) were prepared via Reversible Addition-Fragmentation Chain Transfer (RAFT) copolymerization. Following confirmation of PSMA expression on C4-2 cell line, the DTX conjugates' in vitro cytotoxicity was tested against C4-2 tumor cells and their anticancer efficacies were assessed in nude mice bearing s.c. human prostate adenocarcinoma C4-2 xenografts. The in vivo results show that the spacer length between targeting moieties and HPMA copolymer backbone can significantly affect the treatment efficacy of DTX conjugates against C4-2 tumor bearing nu/nu mice. Moreover, histological analysis indicated that the DUPA-targeted DTX conjugate with longer spacer had no toxicity in major organs of treated mice.

  10. Pearls and pitfalls in clinical interpretation of prostate-specific membrane antigen (PSMA)-targeted PET imaging

    International Nuclear Information System (INIS)

    Sheikhbahaei, Sara; Solnes, Lilja B.; Javadi, Mehrbod S.; Pomper, Martin G.; Rowe, Steven P.; Afshar-Oromieh, Ali; Haberkorn, Uwe; Eiber, Matthias; Ross, Ashley E.; Pienta, Kenneth J.; Allaf, Mohamad E.; Gorin, Michael A.

    2017-01-01

    The rapidly expanding clinical adaptation of prostate-specific membrane antigen (PSMA)-targeted PET imaging in the evaluation of patients with prostate cancer has placed an increasing onus on understanding both the potential pearls of interpretation as well as limitations of this new technique. As with any new molecular imaging modality, accurate characterization of abnormalities on PSMA-targeted PET imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants of radiotracer uptake, and potential sources of false-positive and false-negative imaging findings. In recent years, a growing number of reports have come to light describing incidental non-prostatic benign or malignant pathologies with high uptake on PSMA-targeted PET imaging. In this review, we have summarized the published literature regarding the potential pearls and technical and interpretive pitfalls of this imaging modality. Knowledge of these limitations can increase the confidence of interpreting physicians and thus improve patient care. As PSMA-targeted PET is expected to be evaluated in larger prospective trials, the dissemination of potential diagnostic pitfalls and the biologic underpinning of those findings will be of increased importance. (orig.)

  11. Prostate-specific membrane antigen PET/MRI validation of MR textural analysis for detection of transition zone prostate cancer

    International Nuclear Information System (INIS)

    Bates, Anthony; Miles, Kenneth

    2017-01-01

    To validate MR textural analysis (MRTA) for detection of transition zone (TZ) prostate cancer through comparison with co-registered prostate-specific membrane antigen (PSMA) PET-MR. Retrospective analysis was performed for 30 men who underwent simultaneous PSMA PET-MR imaging for staging of prostate cancer. Thirty texture features were derived from each manually contoured T2-weighted, transaxial, prostatic TZ using texture analysis software that applies a spatial band-pass filter and quantifies texture through histogram analysis. Texture features of the TZ were compared to PSMA expression on the corresponding PET images. The Benjamini-Hochberg correction controlled the false discovery rate at <5%. Eighty-eight T2-weighted images in 18 patients demonstrated abnormal PSMA expression within the TZ on PET-MR. 123 images were PSMA negative. Based on the corrected p-value of 0.005, significant differences between PSMA positive and negative slices were found for 16 texture parameters: Standard deviation and mean of positive pixels for all spatial filters (p = <0.0001 for both at all spatial scaling factor (SSF) values) and mean intensity following filtration for SSF 3-6 mm (p = 0.0002-0.0018). Abnormal expression of PSMA within the TZ is associated with altered texture on T2-weighted MR, providing validation of MRTA for the detection of TZ prostate cancer. (orig.)

  12. Prostate-specific membrane antigen PET/MRI validation of MR textural analysis for detection of transition zone prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Anthony [Princess Alexandra Hospital, Brisbane (Australia); Miles, Kenneth [Princess Alexandra Hospital, Department of Diagnostic Radiology, Brisbane, QLD (Australia); University College London, Institute of Nuclear Medicine, London (United Kingdom)

    2017-12-15

    To validate MR textural analysis (MRTA) for detection of transition zone (TZ) prostate cancer through comparison with co-registered prostate-specific membrane antigen (PSMA) PET-MR. Retrospective analysis was performed for 30 men who underwent simultaneous PSMA PET-MR imaging for staging of prostate cancer. Thirty texture features were derived from each manually contoured T2-weighted, transaxial, prostatic TZ using texture analysis software that applies a spatial band-pass filter and quantifies texture through histogram analysis. Texture features of the TZ were compared to PSMA expression on the corresponding PET images. The Benjamini-Hochberg correction controlled the false discovery rate at <5%. Eighty-eight T2-weighted images in 18 patients demonstrated abnormal PSMA expression within the TZ on PET-MR. 123 images were PSMA negative. Based on the corrected p-value of 0.005, significant differences between PSMA positive and negative slices were found for 16 texture parameters: Standard deviation and mean of positive pixels for all spatial filters (p = <0.0001 for both at all spatial scaling factor (SSF) values) and mean intensity following filtration for SSF 3-6 mm (p = 0.0002-0.0018). Abnormal expression of PSMA within the TZ is associated with altered texture on T2-weighted MR, providing validation of MRTA for the detection of TZ prostate cancer. (orig.)

  13. Spatial organization of the cytoskeleton enhances cargo delivery to specific target areas on the plasma membrane of spherical cells.

    Science.gov (United States)

    Hafner, Anne E; Rieger, Heiko

    2016-11-15

    Intracellular transport is vital for the proper functioning and survival of a cell. Cargo (proteins, vesicles, organelles, etc) is transferred from its place of creation to its target locations via molecular motor assisted transport along cytoskeletal filaments. The transport efficiency is strongly affected by the spatial organization of the cytoskeleton, which constitutes an inhomogeneous, complex network. In cells with a centrosome microtubules grow radially from the central microtubule organizing center towards the cell periphery whereas actin filaments form a dense meshwork, the actin cortex, underneath the cell membrane with a broad range of orientations. The emerging ballistic motion along filaments is frequently interrupted due to constricting intersection nodes or cycles of detachment and reattachment processes in the crowded cytoplasm. In order to investigate the efficiency of search strategies established by the cell's specific spatial organization of the cytoskeleton we formulate a random velocity model with intermittent arrest states. With extensive computer simulations we analyze the dependence of the mean first passage times for narrow escape problems on the structural characteristics of the cytoskeleton, the motor properties and the fraction of time spent in each state. We find that an inhomogeneous architecture with a small width of the actin cortex constitutes an efficient intracellular search strategy.

  14. Microfluidic-integrated patterned ITO immunosensor for rapid detection of prostate-specific membrane antigen biomarker in prostate cancer.

    Science.gov (United States)

    Seenivasan, Rajesh; Singh, Chandra K; Warrick, Jay W; Ahmad, Nihal; Gunasekaran, Sundaram

    2017-09-15

    An optically transparent patterned indium tin oxide (ITO) three-electrode sensor integrated with a microfluidic channel was designed for label-free immunosensing of prostate-specific membrane antigen (PSMA), a prostate cancer (PCa) biomarker, expressed on prostate tissue and circulating tumor cells but also found in serum. The sensor relies on cysteamine capped gold nanoparticles (N-AuNPs) covalently linked with anti-PSMA antibody (Ab) for target specificity. A polydimethylsiloxane (PDMS) microfluidic channel is used to efficiently and reproducibly introduce sample containing soluble proteins/cells to the sensor. The PSMA is detected and quantified by measuring the change in differential pulse voltammetry signal of a redox probe ([Fe(CN) 6 ] 3- /[Fe(CN) 6 ] 4- ) that is altered upon binding of PSMA with PSMA-Ab immobilized on N-AuNPs/ITO. Detection of PSMA expressing cells and soluble PSMA was tested. The limit of detection (LOD) of the sensor for PSMA-based PCa cells is 6/40µL (i.e., 150 cells/mL) (n=3) with a linear range of 15-400 cells/40µL (i.e., 375-10,000 cells/mL), and for the soluble PSMA is 0.499ng/40µL (i.e., 12.5ng/mL) (n=3) with the linear range of 0.75-250ng/40µL (i.e., 19-6250ng/mL), both with an incubation time of 10min. The results indicate that the sensor has a suitable sensitivity and dynamic range for routine detection of PCa circulating tumor cells and can be adapted to detect other biomarkers/cancer cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Defining the extreme substrate specificity of Euonymus alatus diacylglycerol acetyltransferase, an unusual membrane-bound O-acyltransferase

    Science.gov (United States)

    Bansal, Sunil; Durrett, Timothy P.

    2016-01-01

    Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) synthesizes the unusually structured 3-acetyl-1,2-diacylglycerols (acetyl-TAG) found in the seeds of a few plant species. A member of the membrane-bound O-acyltransferase (MBOAT) family, EaDAcT transfers the acetyl group from acetyl-CoA to sn-1,2-diacylglycerol (DAG) to produce acetyl-TAG. In vitro assays demonstrated that the enzyme is also able to utilize butyryl-CoA and hexanoyl-CoA as acyl donors, though with much less efficiency compared with acetyl-CoA. Acyl-CoAs longer than eight carbons were not used by EaDAcT. This extreme substrate specificity of EaDAcT distinguishes it from all other MBOATs which typically catalyze the transfer of much longer acyl groups. In vitro selectivity experiments revealed that EaDAcT preferentially acetylated DAG molecules containing more double bonds over those with less. However, the enzyme was also able to acetylate saturated DAG containing medium chain fatty acids, albeit with less efficiency. Interestingly, EaDAcT could only acetylate the free hydroxyl group of sn-1,2-DAG but not the available hydroxyl groups in sn-1,3-DAG or in monoacylglycerols (MAG). Consistent with its similarity to the jojoba wax synthase, EaDAcT could acetylate fatty alcohols in vitro to produce alkyl acetates. Likewise, when coexpressed in yeast with a fatty acyl-CoA reductase capable of producing fatty alcohols, EaDAcT synthesized alkyl acetates although the efficiency of production was low. This improved understanding of EaDAcT specificity confirms that the enzyme preferentially utilizes acetyl-CoA to acetylate sn-1,2-DAGs and will be helpful in engineering the production of acetyl-TAG with improved functionality in transgenic plants. PMID:27688773

  16. Prostate-specific membrane antigen-based imaging in prostate cancer: impact on clinical decision making process.

    Science.gov (United States)

    Demirkol, Mehmet Onur; Acar, Ömer; Uçar, Burcu; Ramazanoğlu, Sultan Rana; Sağlıcan, Yeşim; Esen, Tarık

    2015-05-01

    There is an ongoing need for an accurate imaging modality which can be used for staging purposes, metastatic evaluation, predicting biologic aggresiveness and investigating recurrent disease in prostate cancer. Prostate specific membrane antigen, given its favorable molecular characteristics, holds a promise as an ideal target for prostate cancer-specific nuclear imaging. In this study, we evaluated our initial results of PSMA based PET/CT imaging in prostate cancer. A total of 22 patients with a median age and serum PSA level of 68 years and 4.15 ng/ml, respectively underwent Ga-68 PSMA PET/CT in our hospital between Februrary and August 2014. Their charts were retrospectively reviewed in order to document the clinical characteristics, the indications for and the results of PSMA based imaging and the impact of Ga-68 PSMA PET/CT findings on disease management. The most common indications were rising PSA after local ± adjuvant treatment followed by staging and metastatic evaluation before definitive or salvage treatment. All except 2 patients had prostatic ± extraprostatic PSMA positive lesions. For those who had a positive result; treatment strategies were tailored accordingly. Above the PSA level of 2 ng/ml, none of the PSMA based nuclear imaging studies revealed negative results. PSMA based nuclear imaging has significantly impacted our way of handling patients with prostate cancer. Its preliminary performance in different clinical scenarios and ability to detect lesions even in low PSA values seems fairly promising and deserves to be supplemented with further clinical studies. © 2015 Wiley Periodicals, Inc.

  17. Why bother about depth?

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Obrador, Biel; Christensen, Jesper Philip

    We present results from a newly developed method to determine depth specific rates of GPP, NEP and R using frequent automated profiles of DO and temperature. Metabolic rate calculations were made for three lakes of different trophic status using a diel DO methodology that integrates rates across...

  18. Effect of prostate-specific membrane antigen positron emission tomography on the decision-making of radiation oncologists

    International Nuclear Information System (INIS)

    Shakespeare, Thomas P.

    2015-01-01

    Positron emission tomography (PET) imaging is routinely used in many cancer types, although is not yet a standard modality for prostate carcinoma. Prostate-specific membrane antigen (PSMA) PET is a promising new modality for staging prostate cancer, with recent studies showing potential advantages over traditional computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine bone scan imaging. However, the impact of PSMA PET on the decision-making of radiation oncologists and outcomes after radiotherapy is yet to be determined. Our aim was to determine the impact of PSMA PET on a radiation oncologist’s clinical practice. Patients in a radiation oncology clinic who underwent PSMA PET were prospectively recorded in an electronic oncology record. Patient demographics, outcomes of imaging, and impact on decision-making were evaluated. Fifty-four patients underwent PSMA PET between January and May 2015. The major reasons for undergoing PET included staging before definitive (14.8 %) or post-prostatectomy (33.3 %) radiotherapy, and investigation of PSA failures following definitive (16.7 %) or post-prostatectomy (33.3 %) radiotherapy. In 46.3 % of patients PSMA was positive after negative traditional imaging, in 9.3 % PSMA was positive after equivocal imaging, and in 13.0 % PSMA was negative after equivocal imaging. PSMA PET changed radiotherapy management in 46.3 % of cases, and hormone therapy in 33.3 % of patients, with an overall change in decision-making in 53.7 % of patients. PSMA PET has the potential to significantly alter the decision-making of radiation oncologists, and may become a valuable imaging tool in the future

  19. Effect of prostate-specific membrane antigen positron emission tomography on the decision-making of radiation oncologists.

    Science.gov (United States)

    Shakespeare, Thomas P

    2015-11-18

    Positron emission tomography (PET) imaging is routinely used in many cancer types, although is not yet a standard modality for prostate carcinoma. Prostate-specific membrane antigen (PSMA) PET is a promising new modality for staging prostate cancer, with recent studies showing potential advantages over traditional computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine bone scan imaging. However, the impact of PSMA PET on the decision-making of radiation oncologists and outcomes after radiotherapy is yet to be determined. Our aim was to determine the impact of PSMA PET on a radiation oncologist's clinical practice. Patients in a radiation oncology clinic who underwent PSMA PET were prospectively recorded in an electronic oncology record. Patient demographics, outcomes of imaging, and impact on decision-making were evaluated. Fifty-four patients underwent PSMA PET between January and May 2015. The major reasons for undergoing PET included staging before definitive (14.8%) or post-prostatectomy (33.3%) radiotherapy, and investigation of PSA failures following definitive (16.7%) or post-prostatectomy (33.3%) radiotherapy. In 46.3% of patients PSMA was positive after negative traditional imaging, in 9.3% PSMA was positive after equivocal imaging, and in 13.0% PSMA was negative after equivocal imaging. PSMA PET changed radiotherapy management in 46.3% of cases, and hormone therapy in 33.3% of patients, with an overall change in decision-making in 53.7% of patients. PSMA PET has the potential to significantly alter the decision-making of radiation oncologists, and may become a valuable imaging tool in the future.

  20. Vascular targeted therapy with anti-prostate-specific membrane antigen monoclonal antibody J591 in advanced solid tumors.

    Science.gov (United States)

    Milowsky, Matthew I; Nanus, David M; Kostakoglu, Lale; Sheehan, Christine E; Vallabhajosula, Shankar; Goldsmith, Stanley J; Ross, Jeffrey S; Bander, Neil H

    2007-02-10

    Based on prostate-specific membrane antigen (PSMA) expression on the vasculature of solid tumors, we performed a phase I trial of antibody J591, targeting the extracellular domain of PSMA, in patients with advanced solid tumor malignancies. This was a proof-of-principle evaluation of PSMA as a potential neovascular target. The primary end points were targeting,toxicity, maximum-tolerated dose, pharmacokinetics (PK), and human antihuman antibody (HAHA) response. Patients had advanced solid tumors previously shown to express PSMA on the neovasculature. They received 111Indium (111ln)-J591 for scintigraphy and PK, followed 2 weeks later by J591 with a reduced amount of 111In for additional PK measurements. J591 dose levels were 5, 10, 20, 40, and 80 mg. The protocol was amended for six weekly administrations of unchelated J591. Patients with a response or stable disease were eligible for re-treatment. Immunohistochemistry assessed PSMA expression in tumor tissues. Twenty-seven patients received monoclonal antibody (mAb) J591. Treatment was well tolerated. Twenty (74%) of 27 patients had at least one area of known metastatic disease targeted by 111In-J591, with positive imaging seen in patients with kidney, bladder, lung, breast, colorectal, and pancreatic cancers, and melanoma. Seven of 10 patient specimens available for immunohistochemical assessment of PSMA expression in tumor-associated vasculature demonstrated PSMA staining. No HAHA response was seen. Three patients of 27 with stable disease received re-treatment. Acceptable toxicity and excellent targeting of known sites of metastases were demonstrated in patients with multiple solid tumor types, highlighting a potential role for the anti-PSMA antibody J591 as a vascular-targeting agent.

  1. Sorting of an integral outer membrane protein via the lipoprotein-specific Lol pathway and a dedicated lipoprotein pilotin.

    Science.gov (United States)

    Collin, Séverine; Guilvout, Ingrid; Nickerson, Nicholas N; Pugsley, Anthony P

    2011-05-01

    The lipoprotein PulS is a dedicated chaperone that is required to target the secretin PulD to the outer membrane in Klebsiella or Escherichia coli, and to protect it from proteolysis. Here, we present indirect evidence that PulD protomers do not assemble into the secretin dodecamer before they reach the outer membrane, and that PulS reaches the outer membrane in a soluble heterodimer with the general lipoprotein chaperone LolA. However, we could not find any direct evidence for PulD protomer association with the PulS-LolA heterodimer. Instead, in cells producing PulD and a permanently locked PulS-LolA dimer (in which LolA carries an R43L substitution that prevents lipoprotein transfer to LolB in the outer membrane), LolAR43L was found in the inner membrane, probably still associated with PulS bound to PulD that had been incorrectly targeted because of the LolAR43L substitution. It is speculated that PulD protomers normally cross the periplasm together with PulS bound to LolA but when the latter cannot be separated (due to the mutation in lolA), the PulD protomers form dodecamers that insert into the inner membrane. © 2011 Blackwell Publishing Ltd.

  2. Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics

    Science.gov (United States)

    Engebretsen, Erik; Hinds, Gareth; Meyer, Quentin; Mason, Tom; Brightman, Edward; Castanheira, Luis; Shearing, Paul R.; Brett, Daniel J. L.

    2018-04-01

    Advances in bespoke diagnostic techniques for polymer electrolyte fuel cells continue to provide unique insight into the internal operation of these devices and lead to improved performance and durability. Localised measurements of current density have proven to be extremely useful in designing better fuel cells and identifying optimal operating strategies, with electrochemical impedance spectroscopy (EIS) now routinely used to deconvolute the various losses in fuel cells. Combining the two techniques provides another dimension of understanding, but until now each localised EIS has been based on 2-electrode measurements, composed of both the anode and cathode responses. This work shows that a reference electrode array can be used to give individual electrode-specific EIS responses, in this case the cathode is focused on to demonstrate the approach. In addition, membrane hydration dynamics are studied under current load steps from open circuit voltage. A three-stage process is identified associated with an initial rapid reduction in membrane resistance after 10 s of applying a current step, followed by a slower ramp to approximately steady state, which was achieved after ∼250 s. These results support previously published work that has looked at membrane swelling dynamics and reveal that membrane hydration/membrane resistance is highly heterogeneous.

  3. The tissue-specific Rep8/UBXD6 tethers p97 to the endoplasmic reticulum membrane for degradation of misfolded proteins.

    Directory of Open Access Journals (Sweden)

    Louise Madsen

    Full Text Available The protein known as p97 or VCP in mammals and Cdc48 in yeast is a versatile ATPase complex involved in several biological functions including membrane fusion, protein folding, and activation of membrane-bound transcription factors. In addition, p97 plays a central role in degradation of misfolded secretory proteins via the ER-associated degradation pathway. This functional diversity of p97 depends on its association with various cofactors, and to further our understanding of p97 function it is important that these cofactors are identified and analyzed. Here, we isolate and characterize the human protein named Rep8 or Ubxd6 as a new cofactor of p97. Mouse Rep8 is highly tissue-specific and abundant in gonads. In testes, Rep8 is expressed in post-meiotic round spermatids, whereas in ovaries Rep8 is expressed in granulosa cells. Rep8 associates directly with p97 via its UBX domain. We show that Rep8 is a transmembrane protein that localizes to the ER membrane with its UBX domain facing the cytoplasm. Knock-down of Rep8 expression in human cells leads to a decreased association of p97 with the ER membrane and concomitantly a retarded degradation of misfolded ER-derived proteasome substrates. Thus, Rep8 tethers p97 to the ER membrane for efficient ER-associated degradation.

  4. Specific binding of [alpha-32P]GTP to cytosolic and membrane-bound proteins of human platelets correlates with the activation of phospholipase C

    International Nuclear Information System (INIS)

    Lapetina, E.G.; Reep, B.R.

    1987-01-01

    We have assessed the binding of [alpha- 32 P]GTP to platelet proteins from cytosolic and membrane fractions. Proteins were separated by NaDodSO 4 /PAGE and electrophoretically transferred to nitrocellulose. Incubation of the nitrocellulose blots with [alpha- 32 P]GTP indicated the presence of specific and distinct GTP-binding proteins in cytosol and membranes. Binding was prevented by 10-100 nM GTP and by 100 nM guanosine 5'-[gamma-thio]triphosphate (GTP[gamma S]) or GDP; binding was unaffected by 1 nM-1 microM ATP. One main GTP-binding protein (29.5 kDa) was detected in the membrane fraction, while three others (29, 27, and 21 kDa) were detected in the soluble fraction. Two cytosolic GTP-binding proteins (29 and 27 kDa) were degraded by trypsin; another cytosolic protein (21 kDa) and the membrane-bound protein (29.5 kDa) were resistant to the action of trypsin. Treatment of intact platelets with trypsin or thrombin, followed by lysis and fractionation, did not affect the binding of [alpha- 32 P]GTP to the membrane-bound protein. GTP[gamma S] still stimulated phospholipase C in permeabilized platelets already preincubated with trypsin. This suggests that trypsin-resistant GTP-binding proteins might regulate phospholipase C stimulated by GTP[gamma S

  5. Residue-specific membrane location of peptides and proteins using specifically and extensively deuterated lipids and {sup 13}C-{sup 2}H rotational-echo double-resonance solid-state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Xie Li; Ghosh, Ujjayini; Schmick, Scott D.; Weliky, David P., E-mail: weliky@chemistry.msu.edu [Michigan State University, Department of Chemistry (United States)

    2013-01-15

    Residue-specific location of peptides in the hydrophobic core of membranes was examined using {sup 13}C-{sup 2}H REDOR and samples in which the lipids were selectively deuterated. The transmembrane topology of the KALP peptide was validated with this approach with substantial dephasing observed for deuteration in the bilayer center and reduced or no dephasing for deuteration closer to the headgroups. Insertion of {beta} sheet HIV and helical and {beta} sheet influenza virus fusion peptides into the hydrophobic core of the membrane was validated in samples with extensively deuterated lipids.

  6. Prostate-specific membrane antigen targeted protein contrast agents for molecular imaging of prostate cancer by MRI

    Science.gov (United States)

    Pu, Fan; Salarian, Mani; Xue, Shenghui; Qiao, Jingjuan; Feng, Jie; Tan, Shanshan; Patel, Anvi; Li, Xin; Mamouni, Kenza; Hekmatyar, Khan; Zou, Juan; Wu, Daqing; Yang, Jenny J.

    2016-06-01

    Prostate-specific membrane antigen (PSMA) is one of the most specific cell surface markers for prostate cancer diagnosis and targeted treatment. However, achieving molecular imaging using non-invasive MRI with high resolution has yet to be achieved due to the lack of contrast agents with significantly improved relaxivity for sensitivity, targeting capabilities and metal selectivity. We have previously reported our creation of a novel class of protein Gd3+ contrast agents, ProCA32, which displayed significantly improved relaxivity while exhibiting strong Gd3+ binding selectivity over physiological metal ions. In this study, we report our effort in further developing biomarker-targeted protein MRI contrast agents for molecular imaging of PSMA. Among three PSMA targeted contrast agents engineered with addition of different molecular recognition sequences, ProCA32.PSMA exhibits a binding affinity of 1.1 +/- 0.1 μM for PSMA while the metal binding affinity is maintained at 0.9 +/- 0.1 × 10-22 M. In addition, ProCA32.PSMA exhibits r1 of 27.6 mM-1 s-1 and r2 of 37.9 mM-1 s-1 per Gd (55.2 and 75.8 mM-1 s-1 per molecule r1 and r2, respectively) at 1.4 T. At 7 T, ProCA32.PSMA also has r2 of 94.0 mM-1 s-1 per Gd (188.0 mM-1 s-1 per molecule) and r1 of 18.6 mM-1 s-1 per Gd (37.2 mM-1 s-1 per molecule). This contrast capability enables the first MRI enhancement dependent on PSMA expression levels in tumor bearing mice using both T1 and T2-weighted MRI at 7 T. Further development of these PSMA-targeted contrast agents are expected to be used for the precision imaging of prostate cancer at an early stage and to monitor disease progression and staging, as well as determine the effect of therapeutic treatment by non-invasive evaluation of the PSMA level using MRI.Prostate-specific membrane antigen (PSMA) is one of the most specific cell surface markers for prostate cancer diagnosis and targeted treatment. However, achieving molecular imaging using non-invasive MRI with high

  7. Membrane vesicles from multidrug-resistant human carcinoma cells contain a specific 150,000-170,000 dalton protein detected by photoaffinity labeling

    International Nuclear Information System (INIS)

    Cornwell, M.M.; Safa, A.R.; Felsted, R.L.; Gottesman, M.M.; Pastan, I.

    1986-01-01

    The authors have selected multidrug-resistant human KB carcinoma cells in high levels of colchicine (KB-C4) or vinblastine (KB-V1) which are cross-resistant to many other structurally unrelated chemotheraputic agents. To determine the mechanism of reduced drug accumulation, they measured 3 H-vinblastine ( 3 H-VBL) association with membrane vesicles made from parental drug sensitive, drug-resistant and revertant cells. Membrane vesicles from highly multidrug resistant cells exhibited increased specific and saturable binding of vinblastine, (Kd = 1 μM) that was temperature dependent and trypsin sensitive. To identify the molecules which bind vinblastine, membrane vesicles were exposed to two photo-activatable analogs of vinblastine, (N-P-(azido-3,5,-[ 3 H]-benzoyl)-N'-β-aminoethylvindisine ( 3 H-NAB) and N-P-(azido-3-[ 125 I]-solicyl)-N'-β-aminoethylvindesine ( 125 I-NASV). The specific labeling of a 150,000-170,000 dalton protein in membrane vesicles from multidrug-resistant KB-C4 and KB-V1 cells was found. 125 I-NASV labeling was inhibited by vinblastine, vincrinstine and verapamil but not by colchicine or dexamethasone. The 150,000-170,000 dalton protein may have an important role in the multidrug resistance phenotype

  8. Impedimetric DNA Biosensor Based on a Nanoporous Alumina Membrane for the Detection of the Specific Oligonucleotide Sequence of Dengue Virus

    Directory of Open Access Journals (Sweden)

    Chee-Seng Toh

    2013-06-01

    Full Text Available A novel and integrated membrane sensing platform for DNA detection is developed based on an anodic aluminum oxide (AAO membrane. Platinum electrodes (~50–100 nm thick are coated directly on both sides of the alumina membrane to eliminate the solution resistance outside the nanopores. The electrochemical impedance technique is employed to monitor the impedance changes within the nanopores upon DNA binding. Pore resistance (Rp linearly increases in response towards the increasing concentration of the target DNA in the range of 1 × 10−12 to 1 × 10−6 M. Moreover, the biosensor selectively differentiates the complementary sequence from single base mismatched (MM-1 strands and non-complementary strands. This study reveals a simple, selective and sensitive method to fabricate a label-free DNA biosensor.

  9. Impedimetric DNA biosensor based on a nanoporous alumina membrane for the detection of the specific oligonucleotide sequence of dengue virus.

    Science.gov (United States)

    Deng, Jiajia; Toh, Chee-Seng

    2013-06-17

    A novel and integrated membrane sensing platform for DNA detection is developed based on an anodic aluminum oxide (AAO) membrane. Platinum electrodes (~50-100 nm thick) are coated directly on both sides of the alumina membrane to eliminate the solution resistance outside the nanopores. The electrochemical impedance technique is employed to monitor the impedance changes within the nanopores upon DNA binding. Pore resistance (Rp) linearly increases in response towards the increasing concentration of the target DNA in the range of 1 × 10⁻¹² to 1 × 10⁻⁶ M. Moreover, the biosensor selectively differentiates the complementary sequence from single base mismatched (MM-1) strands and non-complementary strands. This study reveals a simple, selective and sensitive method to fabricate a label-free DNA biosensor.

  10. Membrane cholesterol removal changes mechanical properties of cells and induces secretion of a specific pool of lysosomes.

    Science.gov (United States)

    Hissa, Barbara; Pontes, Bruno; Roma, Paula Magda S; Alves, Ana Paula; Rocha, Carolina D; Valverde, Thalita M; Aguiar, Pedro Henrique N; Almeida, Fernando P; Guimarães, Allan J; Guatimosim, Cristina; Silva, Aristóbolo M; Fernandes, Maria C; Andrews, Norma W; Viana, Nathan B; Mesquita, Oscar N; Agero, Ubirajara; Andrade, Luciana O

    2013-01-01

    In a previous study we had shown that membrane cholesterol removal induced unregulated lysosomal exocytosis events leading to the depletion of lysosomes located at cell periphery. However, the mechanism by which cholesterol triggered these exocytic events had not been uncovered. In this study we investigated the importance of cholesterol in controlling mechanical properties of cells and its connection with lysosomal exocytosis. Tether extraction with optical tweezers and defocusing microscopy were used to assess cell dynamics in mouse fibroblasts. These assays showed that bending modulus and surface tension increased when cholesterol was extracted from fibroblasts plasma membrane upon incubation with MβCD, and that the membrane-cytoskeleton relaxation time increased at the beginning of MβCD treatment and decreased at the end. We also showed for the first time that the amplitude of membrane-cytoskeleton fluctuation decreased during cholesterol sequestration, showing that these cells become stiffer. These changes in membrane dynamics involved not only rearrangement of the actin cytoskeleton, but also de novo actin polymerization and stress fiber formation through Rho activation. We found that these mechanical changes observed after cholesterol sequestration were involved in triggering lysosomal exocytosis. Exocytosis occurred even in the absence of the lysosomal calcium sensor synaptotagmin VII, and was associated with actin polymerization induced by MβCD. Notably, exocytosis triggered by cholesterol removal led to the secretion of a unique population of lysosomes, different from the pool mobilized by actin depolymerizing drugs such as Latrunculin-A. These data support the existence of at least two different pools of lysosomes with different exocytosis dynamics, one of which is directly mobilized for plasma membrane fusion after cholesterol removal.

  11. Ultrastructural localization of the core protein of a basement membrane-specific chondroitin sulfate proteoglycan in adult rat skin

    DEFF Research Database (Denmark)

    McCarthy, K J; Horiguchi, Y; Couchman, J R

    1990-01-01

    Basement membranes are complex extracellular matrices present at epithelial/mesenchymal interfaces of tissues. The dermal-epidermal junction has been shown to contain numerous components, some of the most well known being laminin, types IV and VII collagens, heparan sulfate proteoglycan, fibronec...

  12. A specific type of membrane microdomains is involved in the maintenance and translocation of kinase active Lck to lipid rafts

    Czech Academy of Sciences Publication Activity Database

    Ballek, Ondřej; Broučková, Adéla; Manning, Jasper; Filipp, Dominik

    2012-01-01

    Roč. 142, 1-2 (2012), s. 64-74 ISSN 0165-2478 R&D Projects: GA ČR GA310/09/2084 Institutional research plan: CEZ:AV0Z50520514 Keywords : pY394Lck * T-cell proximal signaling * membrane microdomains Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.337, year: 2012

  13. Membrane fusion activity of Semliki forest virus in a liposomal model system : Specific inhibition by Zn2+ ions

    NARCIS (Netherlands)

    Corver, J; Snippe, H; Kraaijeveld, C; Wilschut, J

    1997-01-01

    Semliki Forest virus (SFV) has been shown previously to fuse efficiently with cholesterol-and sphingolipid-containing liposomal model membranes in a low-pH-dependent manner. Several steps can be distinguished in this process, including low-pH-induced irreversible binding of the virus to the

  14. Prostate cancer nodal oligometastasis accurately assessed using prostate-specific membrane antigen positron emission tomography-computed tomography and confirmed histologically following robotic-assisted lymph node dissection.

    Science.gov (United States)

    O'Kane, Dermot B; Lawrentschuk, Nathan; Bolton, Damien M

    2016-01-01

    We herein present a case of a 76-year-old gentleman, where prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT) was used to accurately detect prostate cancer (PCa), pelvic lymph node (LN) metastasis in the setting of biochemical recurrence following definitive treatment for PCa. The positive PSMA PET-CT result was confirmed with histological examination of the involved pelvic LNs following pelvic LN dissection.

  15. Prostate cancer nodal oligometastasis accurately assessed using prostate-specific membrane antigen positron emission tomography-computed tomography and confirmed histologically following robotic-assisted lymph node dissection

    Directory of Open Access Journals (Sweden)

    Dermot B O′Kane

    2016-01-01

    Full Text Available We herein present a case of a 76-year-old gentleman, where prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT was used to accurately detect prostate cancer (PCa, pelvic lymph node (LN metastasis in the setting of biochemical recurrence following definitive treatment for PCa. The positive PSMA PET-CT result was confirmed with histological examination of the involved pelvic LNs following pelvic LN dissection.

  16. Structural and biophysical characterization of an epitope-specific engineered Fab fragment and complexation with membrane proteins: implications for co-crystallization.

    Science.gov (United States)

    Johnson, Jennifer L; Entzminger, Kevin C; Hyun, Jeongmin; Kalyoncu, Sibel; Heaner, David P; Morales, Ivan A; Sheppard, Aly; Gumbart, James C; Maynard, Jennifer A; Lieberman, Raquel L

    2015-04-01

    Crystallization chaperones are attracting increasing interest as a route to crystal growth and structure elucidation of difficult targets such as membrane proteins. While strategies to date have typically employed protein-specific chaperones, a peptide-specific chaperone to crystallize multiple cognate peptide epitope-containing client proteins is envisioned. This would eliminate the target-specific chaperone-production step and streamline the co-crystallization process. Previously, protein engineering and directed evolution were used to generate a single-chain variable (scFv) antibody fragment with affinity for the peptide sequence EYMPME (scFv/EE). This report details the conversion of scFv/EE to an anti-EE Fab format (Fab/EE) followed by its biophysical characterization. The addition of constant chains increased the overall stability and had a negligible impact on the antigen affinity. The 2.0 Å resolution crystal structure of Fab/EE reveals contacts with larger surface areas than those of scFv/EE. Surface plasmon resonance, an enzyme-linked immunosorbent assay, and size-exclusion chromatography were used to assess Fab/EE binding to EE-tagged soluble and membrane test proteins: namely, the β-barrel outer membrane protein intimin and α-helical A2a G protein-coupled receptor (A2aR). Molecular-dynamics simulation of the intimin constructs with and without Fab/EE provides insight into the energetic complexities of the co-crystallization approach.

  17. The tissue-specific Rep8/UBXD6 tethers p97 to the endoplasmic reticulum membrane for degradation of misfolded proteins

    DEFF Research Database (Denmark)

    Madsen, Louise; Kriegenburg, Franziska; Lages Lino Vala, Andrea

    2011-01-01

    is a transmembrane protein that localizes to the ER membrane with its UBX domain facing the cytoplasm. Knock-down of Rep8 expression in human cells leads to a decreased association of p97 with the ER membrane and concomitantly a retarded degradation of misfolded ER-derived proteasome substrates. Thus, Rep8 tethers p......The protein known as p97 or VCP in mammals and Cdc48 in yeast is a versatile ATPase complex involved in several biological functions including membrane fusion, protein folding, and activation of membrane-bound transcription factors. In addition, p97 plays a central role in degradation of misfolded...... protein named Rep8 or Ubxd6 as a new cofactor of p97. Mouse Rep8 is highly tissue-specific and abundant in gonads. In testes, Rep8 is expressed in post-meiotic round spermatids, whereas in ovaries Rep8 is expressed in granulosa cells. Rep8 associates directly with p97 via its UBX domain. We show that Rep8...

  18. Hierarchical, domain type-specific acquisition of antibodies to Plasmodium falciparum erythrocyte membrane protein 1 in Tanzanian children

    DEFF Research Database (Denmark)

    Cham, Gerald K K; Turner, Louise; Kurtis, Jonathan D

    2010-01-01

    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of malaria-infected erythrocytes. PfEMP1 attaches to the vascular lining and allows infected erythrocytes to avoid filtration through the spleen. Each parasite genome encodes about 60 diffe...... and play a major role in limiting parasite multiplication in the blood.......Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of malaria-infected erythrocytes. PfEMP1 attaches to the vascular lining and allows infected erythrocytes to avoid filtration through the spleen. Each parasite genome encodes about 60...... different PfEMP1 variants, each PfEMP1 comprises several domains in its extracellular region, and the PfEMP1 repertoire in different parasites contains domain types that are serologically cross-reactive. In this longitudinal study, we followed 672 children living in an area of high malaria transmission...

  19. Binding of two desmin derivatives to the plasma membrane and the nuclear envelope of avian erythrocytes: evidence for a conserved site-specificity in intermediate filament-membrane interactions

    International Nuclear Information System (INIS)

    Georgatos, S.D.; Weber, K.; Geisler, N.; Blobel, G.

    1987-01-01

    Using solution binding assays, the authors found that a 45-kDa fragment of 125 I-labelled desmin, lacking 67 residues from the N terminus, could specifically associate with avian erythrocyte nuclear envelopes but not with plasma membranes from the same cells. It was also observed that a 50-kDa desmin peptide, missing 27 C-terminal residues, retained the ability to bind to both membrane preparations. Displacement experiments with an excess of purified vimentin suggested that the two desmin derivatives were interacting with a previously identified vimentin receptor at the nuclear envelope, the protein lamin B. Additional analysis by affinity chromatography confirmed this conclusion. Employing an overlay assay, they demonstrated that the 50-kDa fragment, but not the 45-kDa desmin peptide, was capable of interacting with the plasma membrane polypeptide ankyrin (a known vimentin attachment site), as was intact vimentin. Conversely, the nuclear envelope protein lamin B was recognized by both fragments but not by a chymotryptic peptide composed solely of the helical rod domain of desmin. These data imply that the lamin B-binding site on desmin resides within the 21 residues following its helical rod domain, whereas the ankyrin-associating region is localized within its N-terminal head domain, exactly as in the case of vimentin

  20. GRP1 PH Domain, Like AKT1 PH Domain, Possesses a Sentry Glutamate Residue Essential for Specific Targeting to Plasma Membrane PI(3,4,5)P3

    Science.gov (United States)

    Pilling, Carissa; Landgraf, Kyle E.; Falke, Joseph J.

    2011-01-01

    During the appearance of the signaling lipid PI(3,4,5)P3, an important subset of pleckstrin homology (PH) domains target signaling proteins to the plasma membrane. To ensure proper pathway regulation, such PI(3,4,5)P3-specific PH domains must exclude the more prevalant, constitutive plasma membrane lipid PI(4,5)P2 and bind the rare PI(3,4,5)P3 target lipid with sufficiently high affinity. Our previous study of the E17K mutant of protein kinase B (AKT1) PH domain, together with evidence from Carpten et al (1), revealed that the native AKT1 E17 residue serves as a sentry glutamate that excludes PI(4,5)P2, thereby playing an essential role in specific PI(3,4,5)P3 targeting (2). The sentry glutamate hypothesis proposes that an analogous sentry glutamate residue is a widespread feature of PI(3,4,5)P3-specific PH domains, and that charge reversal mutation at the sentry glutamate position will yield both increased PI(4,5)P2 affinity and constitutive plasma membrane targeting. To test this hypothesis the present study investigates the E345 residue, a putative sentry glutamate, of General Receptor for Phosphoinositides 1 (GRP1) PH domain. The results show that incorporation of the E345K charge reversal mutation into GRP1 PH domain enhances PI(4,5)P2 affinity 8-fold and yields constitutive plasma membrane targeting in cells, reminiscent of the effects of the E17K mutation in AKT1 PH domain. Hydrolysis of plasma membrane PI(4,5)P2 releases E345K GRP1 PH domain into the cytoplasm and the efficiency of this release increases when target Arf6 binding is disrupted. Overall, the findings provide strong support for the sentry glutamate hypothesis and suggest that the GRP1 E345K mutation will be linked to changes in cell physiology and human pathologies, as demonstrated for AKT1 E17K (1, 3). Analysis of available PH domain structures suggests that a lone glutamate residue (or, in some cases an aspartate) is a common, perhaps ubiquitous, feature of PI(3,4,5)P3-specific binding

  1. Expression of the Gastrin-Releasing Peptide Receptor, the Prostate Stem Cell Antigen and the Prostate-Specific Membrane Antigen in Lymph Node and Bone Metastases of Prostate Cancer

    NARCIS (Netherlands)

    Ananias, Hildo J. K.; van den Heuvel, Marius C.; Helfrich, Wijnand; de Jong, Igle J.

    2009-01-01

    OBJECTIVE. Cell membrane antigens like the gastrin-releasing peptide receptor (GRPR), the prostate stem cell antigen (PSCA), and the prostate-specific membrane antigen (PSMA), expressed in prostate cancer, are attractive targets for new therapeutic and diagnostic applications. Therefore, we

  2. Glycan specificity of the Vibrio vulnificus hemolysin lectin outlines evolutionary history of membrane targeting by a toxin family.

    Science.gov (United States)

    Kaus, Katherine; Lary, Jeffrey W; Cole, James L; Olson, Rich

    2014-07-29

    Pore-forming toxins (PFTs) are a class of pathogen-secreted molecules that oligomerize to form transmembrane channels in cellular membranes. Determining the mechanism for how PFTs bind membranes is important in understanding their role in disease and for developing possible ways to block their action. Vibrio vulnificus, an aquatic pathogen responsible for severe food poisoning and septicemia in humans, secretes a PFT called V. vulnificus hemolysin (VVH), which contains a single C-terminal targeting domain predicted to resemble a β-trefoil lectin fold. In order to understand the selectivity of the lectin for glycan motifs, we expressed the isolated VVH β-trefoil domain and used glycan-chip screening to identify that VVH displays a preference for terminal galactosyl groups including N-acetyl-d-galactosamine and N-acetyl-d-lactosamine. The X-ray crystal structure of the VVH lectin domain solved to 2.0Å resolution reveals a heptameric ring arrangement similar to the oligomeric form of the related, but inactive, lectin from Vibrio cholerae cytolysin. Structures bound to glycerol, N-acetyl-d-galactosamine, and N-acetyl-d-lactosamine outline a common and versatile mode of recognition allowing VVH to target a wide variety of cell-surface ligands. Sequence analysis in light of our structural and functional data suggests that VVH may represent an earlier step in the evolution of Vibrio PFTs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Fluorodeoxyglucose positron emission tomography scan may be helpful in the case of ductal variant prostate cancer when prostate specific membrane antigen ligand positron emission tomography scan is negative

    International Nuclear Information System (INIS)

    McEwan, Louise M.; Wong, David; Yaxley, John

    2017-01-01

    Gallium-68 prostate specific membrane antigen ligand (Ga-68 PSMA) positron emission tomography/computed tomography (PET/CT) scanning is emerging as a useful imaging modality for the staging of suspected and known recurrent or metastatic prostate cancer and in staging of newly diagnosed higher grade prostate cancer. However, we have observed at our institution that in some cases of the more aggressive ductal variant, Ga-68 PSMA uptake has sometimes been poor compared with prominent 18-fluorodeoxyglucose (F-18 FDG) avidity seen in F-18 FDG PET/CT, which would suggest that FDG PET/CT scans are important in staging of ductal pattern prostate cancer.

  4. Recombinant major outer membrane protein (MOMP) of Chlamydophila abortus, Chlamydophila pecorum, and Chlamydia suis as antigens to distinguish chlamydial species-specific antibodies in animal sera.

    Science.gov (United States)

    Hoelzle, Ludwig E; Hoelzle, Katharina; Wittenbrink, Max M

    2004-10-05

    Recombinant major outer membrane proteins (rMOMP) of Chlamydophila (Ch.) abortus, Ch. pecorum, and Chlamydia (C.) suis were used as antigens to distinguish chlamydial species-specific antibodies in (i) immune sera from six rabbits and three pigs raised against native purified elementary bodies, (ii) serum samples from 25 sows vaccinated with Ch. abortus, and (iii) 40 serum samples from four heifers experimentally infected with Ch. abortus. All post-exposition sera contained chlamydial antibodies as confirmed by strong ELISA seroreactivities against the chlamydial LPS. For the rMOMP ELISA mean IgG antibody levels were at least 5.8-fold higher with the particular rMOMP homologous to the chlamydial species used for immunisation or infection than with heterologous rMOMPs (P <0.001). Preferential rMOMP ELISA reactivities of sera were confirmed by Western blotting. The results suggest that the entire chlamydial rMOMP could provide a species-specific serodiagnostic antigen.

  5. Block copolymer membranes for aqueous solution applications

    KAUST Repository

    Nunes, Suzana Pereira

    2016-03-22

    Block copolymers are known for their intricate morphology. We review the state of the art of block copolymer membranes and discuss perspectives in this field. The main focus is on pore morphology tuning with a short introduction on non-porous membranes. The two main strategies for pore formation in block copolymer membranes are (i) film casting and selective block sacrifice and (ii) self-assembly and non-solvent induced phase separation (SNIPS). Different fundamental aspects involved in the manufacture of block copolymer membranes are considered, including factors affecting the equilibrium morphology in solid films, self-assembly of copolymer in solutions and macrophase separation by solvent-non-solvent exchange. Different mechanisms are proposed for different depths of the SNIPS membrane. Block copolymer membranes can be prepared with much narrower pore size distribution than homopolymer membranes. Open questions and indications of what we consider the next development steps are finally discussed. They include the synthesis and application of new copolymers and specific functionalization, adding characteristics to respond to stimuli and chemical environment, polymerization-induced phase separation, and the manufacture of organic-inorganic hybrids.

  6. Block copolymer membranes for aqueous solution applications

    KAUST Repository

    Nunes, Suzana Pereira

    2016-01-01

    Block copolymers are known for their intricate morphology. We review the state of the art of block copolymer membranes and discuss perspectives in this field. The main focus is on pore morphology tuning with a short introduction on non-porous membranes. The two main strategies for pore formation in block copolymer membranes are (i) film casting and selective block sacrifice and (ii) self-assembly and non-solvent induced phase separation (SNIPS). Different fundamental aspects involved in the manufacture of block copolymer membranes are considered, including factors affecting the equilibrium morphology in solid films, self-assembly of copolymer in solutions and macrophase separation by solvent-non-solvent exchange. Different mechanisms are proposed for different depths of the SNIPS membrane. Block copolymer membranes can be prepared with much narrower pore size distribution than homopolymer membranes. Open questions and indications of what we consider the next development steps are finally discussed. They include the synthesis and application of new copolymers and specific functionalization, adding characteristics to respond to stimuli and chemical environment, polymerization-induced phase separation, and the manufacture of organic-inorganic hybrids.

  7. Prostate-Specific Membrane Antigen Positron Emission Tomography-Computed Tomography for Prostate Cancer: Distribution of Disease and Implications for Radiation Therapy Planning.

    Science.gov (United States)

    Gupta, Sandeep K; Watson, Tahne; Denham, Jim; Shakespeare, Thomas P; Rutherford, Natalie; McLeod, Nicholas; Picton, Kevin; Ainsworth, Paul; Bonaventura, Tony; Martin, Jarad M

    2017-11-01

    To explore the prostate-specific membrane antigen (PSMA)-avid distribution of prostate cancer (PC) on positron emission tomography (PET), both at the time of initial diagnosis and at the time of relapse after definitive local treatment. A total of 179 PSMA PET scans in patients with nil or ≤3 lesions on conventional imaging were retrospectively categorized into 3 subgroups: group A, high-risk PC with no prior definitive therapy (n=34); group B, prior prostatectomy (n=75); and group C, prior radiation therapy (n=70). The numbers and locations of the PSMA-avid lesions were mapped. The PSMA-positive lesions were identified subjectively by a nuclear medicine physician on the basis of clinical experience and taking into account the recent literature and artefacts. A total of 893 PSMA-avid lesions were identified; at least 1 lesion was detected in 80% of all scans. A high detection rate was present even at very low serum PSA levels (eg, at PSA ≤0.20 ng/mL in group B, the detection rate was 46%). Thirty-eight percent of studies revealed extrapelvic disease (41%, 31%, and 46% in groups A, B, and C, respectively). Almost one-third of all studies showed only oligometastases (24%, 36%, and 31% in groups A, B, and C, respectively). A large proportion of these (40%) were a solitary lesion. Prostate-specific membrane antigen PET demonstrated a large number of otherwise unknown metastatic lesions. Therefore we recommend PSMA PET for more accurate assessment of disease burden in initial staging of high-risk PC, as well as for restaging in patients with prostate-specific antigen relapse after primary therapies. Furthermore, a high proportion of oligometastases on PSMA PET provides a prime opportunity to investigate the role of targeted local therapies for oligometastatic PCs. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  8. Revisiting interaction specificity reveals neuronal and adipocyte Munc18 membrane fusion regulatory proteins differ in their binding interactions with partner SNARE Syntaxins.

    Directory of Open Access Journals (Sweden)

    Michelle P Christie

    Full Text Available The efficient delivery of cellular cargo relies on the fusion of cargo-carrying vesicles with the correct membrane at the correct time. These spatiotemporal fusion events occur when SNARE proteins on the vesicle interact with cognate SNARE proteins on the target membrane. Regulatory Munc18 proteins are thought to contribute to SNARE interaction specificity through interaction with the SNARE protein Syntaxin. Neuronal Munc18a interacts with Syntaxin1 but not Syntaxin4, and adipocyte Munc18c interacts with Syntaxin4 but not Syntaxin1. Here we show that this accepted view of specificity needs revision. We find that Munc18c interacts with both Syntaxin4 and Syntaxin1, and appears to bind "non-cognate" Syntaxin1 a little more tightly than Syntaxin4. Munc18a binds Syntaxin1 and Syntaxin4, though it interacts with its cognate Syntaxin1 much more tightly. We also observed that when bound to non-cognate Munc18c, Syntaxin1 captures its neuronal SNARE partners SNAP25 and VAMP2, and Munc18c can bind to pre-formed neuronal SNARE ternary complex. These findings reveal that Munc18a and Munc18c bind Syntaxins differently. Munc18c relies principally on the Syntaxin N-peptide interaction for binding Syntaxin4 or Syntaxin1, whereas Munc18a can bind Syntaxin1 tightly whether or not the Syntaxin1 N-peptide is present. We conclude that Munc18a and Munc18c differ in their binding interactions with Syntaxins: Munc18a has two tight binding modes/sites for Syntaxins as defined previously but Munc18c has just one that requires the N-peptide. These results indicate that the interactions between Munc18 and Syntaxin proteins, and the consequences for in vivo function, are more complex than can be accounted for by binding specificity alone.

  9. Specificity of Bacillus thuringiensis endotoxins is correlated with the presence of high-affinity binding sites in the brush border membrane of target insect midguts

    International Nuclear Information System (INIS)

    Hofmann, C.; Vanderbruggen, H.; Hoefte, H.; Van Rie, J.; Jansens, S.; Van Mellaert, H.

    1988-01-01

    Binding studies were performed with two 125 I-labeled Bacillus thuringiensis δ-endotoxins on brush border membrane vesicles prepared from the larval midgut of the tobacco hornworm Manduca sexta or the cabbage butterfly Pieris brassicae. One δ-endotoxin, Bt2-protoxin, is a 130-kDa recombinant crystalline protein from B. thuringiensis subsp. berliner. It kills larvae of both insect species. The active Bt2-toxin is a 60-kDa proteolytic fragment of the Bt2-protoxin. It binds saturably and with high affinity to brush border membrane vesicles from the midgut of both species. The other δ-endotoxin, Bt4412-protoxin, is a 136-kDa crystalline protein from B. thuringiensis subsp. thuringiensis, which is highly toxic for P. brassicae, but not for M. sexta larvae. Bt4412-toxin, obtained after proteolytic activation of Bt4412-protoxin, shows high-affinity saturable binding to P. brassicae vesicles but not to M. sexta vesicles. The correlation between toxicity and specific binding is further strengthened by competition studies. Other B. thuringiensis δ-endotoxins active against M. sexta compete for binding of 125 I-labeled Bt2-toxin to M. sexta vesicles, whereas toxins active against dipteran or coleopteran larvae do not compete. Bt2-toxin and Bt4412-toxin bind to different sites on P. brassicae vesicles

  10. Specific binding of (/sup 3/H)LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, R.F.; Utterback, B.G.; Robertson, D.W.

    1989-05-01

    LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for (/sup 3/H)LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound (/sup 3/H)LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that (/sup 3/H)LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs.

  11. Specific binding of [3H]LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles

    International Nuclear Information System (INIS)

    Kauffman, R.F.; Utterback, B.G.; Robertson, D.W.

    1989-01-01

    LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for [ 3 H]LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound [ 3 H]LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that [ 3 H]LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs

  12. Indentification of amino - acid residues important for the substrate specificity range of yeast plasma membrane Na+/H+-antiporters

    Czech Academy of Sciences Publication Activity Database

    Zimmermannová, Olga; Zavřel, Martin; Sychrová, Hana

    2005-01-01

    Roč. 22, č. S1 (2005), S178-S178 ISSN 0749-503X. [International Conference on Yeast Genetics and Molecular Biology /22./. 07.08.2005-12.08.2005, Bratislava] R&D Projects: GA ČR(CZ) GP204/02/D092; GA AV ČR(CZ) IAA5011407 Institutional research plan: CEZ:AV0Z50110509 Keywords : yeast * Na+/H+ antiporter * K+ transport * substrate specificity Subject RIV: CE - Biochemistry

  13. Metastasis in urothelial carcinoma mimicking prostate cancer metastasis in Ga-68 prostate-specific membrane antigen positron emission tomography-computed tomography in a case of synchronous malignancy

    International Nuclear Information System (INIS)

    Gupta, Manoj; Choudhury, Partha Sarathi; Gupta, Gurudutt; Gandhi, Jatin

    2016-01-01

    Prostate cancer is the second most common cancer in man. It commonly presents with urinary symptoms, bone pain, or diagnosed with elevated prostate-specific antigen.(PSA) levels. Correct staging and early diagnosis of recurrence by a precise imaging tool are the keys for optimum management. Molecular imaging of prostate cancer with Ga-68 prostate-specific membrane antigen.(PSMA), positron emission tomography-computed tomography.(PET-CT) has recently received significant attention and frequently used with a signature to prostate cancer-specific remark. However, this case will highlight the more cautious use of it. A-72-year-old male treated earlier for synchronous double malignancy.(invasive papillary urothelial carcinoma right ureter and carcinoma prostate) presented with rising PSA.(0.51.ng/ml) and referred for Ga-68 PSMA PET-CT, which showed a positive enlarged left supraclavicular lymph node. Lymph node biopsy microscopic and immunohistochemistry examination revealed metastatic carcinoma favoring urothelial origin. Specificity of PSMA scan to prostate cancer has been seen to be compromised in a certain situation mostly due to neoangiogenesis, and false positives emerged in renal cell cancer, differentiated thyroid cancer, glioblastoma, breast cancer brain metastasis, and paravertebral schwannomas. Understanding the causes of false positive will further enhance the confidence of interpretating PSMA scans

  14. DipA, a pore-forming protein in the outer membrane of Lyme disease spirochetes exhibits specificity for the permeation of dicarboxylates.

    Directory of Open Access Journals (Sweden)

    Marcus Thein

    Full Text Available Lyme disease Borreliae are highly dependent on the uptake of nutrients provided by their hosts. Our study describes the identification of a 36 kDa protein that functions as putative dicarboxylate-specific porin in the outer membrane of Lyme disease Borrelia. The protein was purified by hydroxyapatite chromatography from Borrelia burgdorferi B31 and designated as DipA, for dicarboxylate-specific porin A. DipA was partially sequenced, and corresponding genes were identified in the genomes of B. burgdorferi B31, Borrelia garinii PBi and Borrelia afzelii PKo. DipA exhibits high homology to the Oms38 porins of relapsing fever Borreliae. B. burgdorferi DipA was characterized using the black lipid bilayer assay. The protein has a single-channel conductance of 50 pS in 1 M KCl, is slightly selective for anions with a permeability ratio for cations over anions of 0.57 in KCl and is not voltage-dependent. The channel could be partly blocked by different di- and tricarboxylic anions. Particular high stability constants up to about 28,000 l/mol (in 0.1 M KCl were obtained among the 11 tested anions for oxaloacetate, 2-oxoglutarate and citrate. The results imply that DipA forms a porin specific for dicarboxylates which may play an important role for the uptake of specific nutrients in different Borrelia species.

  15. The cellular prion protein interacts with the tissue non-specific alkaline phosphatase in membrane microdomains of bioaminergic neuronal cells.

    Directory of Open Access Journals (Sweden)

    Myriam Ermonval

    Full Text Available BACKGROUND: The cellular prion protein, PrP(C, is GPI anchored and abundant in lipid rafts. The absolute requirement of PrP(C in neurodegeneration associated to prion diseases is well established. However, the function of this ubiquitous protein is still puzzling. Our previous work using the 1C11 neuronal model, provided evidence that PrP(C acts as a cell surface receptor. Besides a ubiquitous signaling function of PrP(C, we have described a neuronal specificity pointing to a role of PrP(C in neuronal homeostasis. 1C11 cells, upon appropriate induction, engage into neuronal differentiation programs, giving rise either to serotonergic (1C11(5-HT or noradrenergic (1C11(NE derivatives. METHODOLOGY/PRINCIPAL FINDINGS: The neuronal specificity of PrP(C signaling prompted us to search for PrP(C partners in 1C11-derived bioaminergic neuronal cells. We show here by immunoprecipitation an association of PrP(C with an 80 kDa protein identified by mass spectrometry as the tissue non-specific alkaline phosphatase (TNAP. This interaction occurs in lipid rafts and is restricted to 1C11-derived neuronal progenies. Our data indicate that TNAP is implemented during the differentiation programs of 1C11(5-HT and 1C11(NE cells and is active at their cell surface. Noteworthy, TNAP may contribute to the regulation of serotonin or catecholamine synthesis in 1C11(5-HT and 1C11(NE bioaminergic cells by controlling pyridoxal phosphate levels. Finally, TNAP activity is shown to modulate the phosphorylation status of laminin and thereby its interaction with PrP. CONCLUSION/SIGNIFICANCE: The identification of a novel PrP(C partner in lipid rafts of neuronal cells favors the idea of a role of PrP in multiple functions. Because PrP(C and laminin functionally interact to support neuronal differentiation and memory consolidation, our findings introduce TNAP as a functional protagonist in the PrP(C-laminin interplay. The partnership between TNAP and PrP(C in neuronal cells may

  16. Allelic diversity of the Plasmodium falciparum erythrocyte membrane protein 1 entails variant-specific red cell surface epitopes.

    Directory of Open Access Journals (Sweden)

    Inès Vigan-Womas

    Full Text Available The clonally variant Plasmodium falciparum PfEMP1 adhesin is a virulence factor and a prime target of humoral immunity. It is encoded by a repertoire of functionally differentiated var genes, which display architectural diversity and allelic polymorphism. Their serological relationship is key to understanding the evolutionary constraints on this gene family and rational vaccine design. Here, we investigated the Palo Alto/VarO and IT4/R29 and 3D7/PF13_003 parasites lines. VarO and R29 form rosettes with uninfected erythrocytes, a phenotype associated with severe malaria. They express an allelic Cys2/group A NTS-DBL1α(1 PfEMP1 domain implicated in rosetting, whose 3D7 ortholog is encoded by PF13_0003. Using these three recombinant NTS-DBL1α(1 domains, we elicited antibodies in mice that were used to develop monovariant cultures by panning selection. The 3D7/PF13_0003 parasites formed rosettes, revealing a correlation between sequence identity and virulence phenotype. The antibodies cross-reacted with the allelic domains in ELISA but only minimally with the Cys4/group B/C PFL1955w NTS-DBL1α. By contrast, they were variant-specific in surface seroreactivity of the monovariant-infected red cells by FACS analysis and in rosette-disruption assays. Thus, while ELISA can differentiate serogroups, surface reactivity assays define the more restrictive serotypes. Irrespective of cumulated exposure to infection, antibodies acquired by humans living in a malaria-endemic area also displayed a variant-specific surface reactivity. Although seroprevalence exceeded 90% for each rosetting line, the kinetics of acquisition of surface-reactive antibodies differed in the younger age groups. These data indicate that humans acquire an antibody repertoire to non-overlapping serotypes within a serogroup, consistent with an antibody-driven diversification pressure at the population level. In addition, the data provide important information for vaccine design, as

  17. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...... for the lateral organization of membranes as wells as for physical properties like bending, permeability and elasticity...

  18. Nod Factor Effects on Root Hair-Specific Transcriptome of Medicago truncatula: Focus on Plasma Membrane Transport Systems and Reactive Oxygen Species Networks.

    Science.gov (United States)

    Damiani, Isabelle; Drain, Alice; Guichard, Marjorie; Balzergue, Sandrine; Boscari, Alexandre; Boyer, Jean-Christophe; Brunaud, Véronique; Cottaz, Sylvain; Rancurel, Corinne; Da Rocha, Martine; Fizames, Cécile; Fort, Sébastien; Gaillard, Isabelle; Maillol, Vincent; Danchin, Etienne G J; Rouached, Hatem; Samain, Eric; Su, Yan-Hua; Thouin, Julien; Touraine, Bruno; Puppo, Alain; Frachisse, Jean-Marie; Pauly, Nicolas; Sentenac, Hervé

    2016-01-01

    Root hairs are involved in water and nutrient uptake, and thereby in plant autotrophy. In legumes, they also play a crucial role in establishment of rhizobial symbiosis. To obtain a holistic view of Medicago truncatula genes expressed in root hairs and of their regulation during the first hours of the engagement in rhizobial symbiotic interaction, a high throughput RNA sequencing on isolated root hairs from roots challenged or not with lipochitooligosaccharides Nod factors (NF) for 4 or 20 h was carried out. This provided a repertoire of genes displaying expression in root hairs, responding or not to NF, and specific or not to legumes. In analyzing the transcriptome dataset, special attention was paid to pumps, transporters, or channels active at the plasma membrane, to other proteins likely to play a role in nutrient ion uptake, NF electrical and calcium signaling, control of the redox status or the dynamic reprogramming of root hair transcriptome induced by NF treatment, and to the identification of papilionoid legume-specific genes expressed in root hairs. About 10% of the root hair expressed genes were significantly up- or down-regulated by NF treatment, suggesting their involvement in remodeling plant functions to allow establishment of the symbiotic relationship. For instance, NF-induced changes in expression of genes encoding plasma membrane transport systems or disease response proteins indicate that root hairs reduce their involvement in nutrient ion absorption and adapt their immune system in order to engage in the symbiotic interaction. It also appears that the redox status of root hair cells is tuned in response to NF perception. In addition, 1176 genes that could be considered as "papilionoid legume-specific" were identified in the M. truncatula root hair transcriptome, from which 141 were found to possess an ortholog in every of the six legume genomes that we considered, suggesting their involvement in essential functions specific to legumes. This

  19. Nod factor effects on root hair-specific transcriptome of Medicago truncatula: focus on plasma membrane transport systems and reactive oxygen species networks

    Directory of Open Access Journals (Sweden)

    Isabelle eDAMIANI

    2016-06-01

    Full Text Available Root hairs are involved in water and nutrient uptake, and thereby in plant autotrophy. In legumes, they also play a crucial role in establishment of rhizobial symbiosis. To obtain a holistic view of Medicago truncatula genes expressed in root hairs and of their regulation during the first hours of the engagement in rhizobial symbiotic interaction, a high throughput RNA sequencing on isolated root hairs from roots challenged or not with lipochitooligosaccharides Nod factors (NF for 4 h or 20 h was carried out. This provided a repertoire of genes displaying expression in root hairs, responding or not to NF and specific or not to legumes. In analyzing the transcriptome dataset, special attention was paid to pumps, transporters or channels active at the plasma membrane, to other proteins likely to play a role in nutrient ion uptake, NF electrical and calcium signaling, control of the redox status or the dynamic reprogramming of root hair transcriptome induced by NF treatment, and to the identification of papilionoid legume-specific genes expressed in root hairs. About 10 percent of the root hair expressed genes were significantly up- or down-regulated by NF treatment, suggesting their involvement in remodeling plant functions to allow establishment of the symbiotic relationship. For instance, NF-induced changes in expression of genes encoding plasma membrane transport systems or disease response proteins indicate that root hairs reduce their involvement in nutrient ion absorption and adapt their immune system in order to engage in the symbiotic interaction. It also appears that the redox status of root hair cells is tuned in response to NF perception. In addition, 1,176 genes that could be considered as papilionoid legume-specific were identified in the M. truncatula root hair transcriptome, from which 141 were found to possess an orthologue in every of the 6 legume genomes that we considered, suggesting their involvement in essential functions

  20. Codon optimisation to improve expression of a Mycobacterium avium ssp. paratuberculosis-specific membrane-associated antigen by Lactobacillus salivarius.

    Science.gov (United States)

    Johnston, Christopher; Douarre, Pierre E; Soulimane, Tewfik; Pletzer, Daniel; Weingart, Helge; MacSharry, John; Coffey, Aidan; Sleator, Roy D; O'Mahony, Jim

    2013-06-01

    Subunit and DNA-based vaccines against Mycobacterium avium ssp. paratuberculosis (MAP) attempt to overcome inherent issues associated with whole-cell formulations. However, these vaccines can be hampered by poor expression of recombinant antigens from a number of disparate hosts. The high G+C content of MAP invariably leads to a codon bias throughout gene expression. To investigate if the codon bias affects recombinant MAP antigen expression, the open reading frame of a MAP-specific antigen MptD (MAP3733c) was codon optimised for expression against a Lactobacillus salivarius host. Of the total 209 codons which constitute MAP3733c, 172 were modified resulting in a reduced G+C content from 61% for the native gene to 32.7% for the modified form. Both genes were placed under the transcriptional control of the PnisA promoter; allowing controlled heterologous expression in L. salivarius. Expression was monitored using fluorescence microscopy and microplate fluorometry via GFP tags translationally fused to the C-termini of the two MptD genes. A > 37-fold increase in expression was observed for the codon-optimised MAP3733synth variant over the native gene. Due to the low cost and improved expression achieved, codon optimisation significantly improves the potential of L. salivarius as an oral vaccine stratagem against Johne's disease. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  1. Overexpression of membrane sialic acid-specific sialidase Neu3 inhibits matrix metalloproteinase-9 expression in vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Moon, Sung-Kwon; Cho, Seung-Hak; Kim, Kyung-Woon; Jeon, Jae Heung; Ko, Jeong-Heon; Kim, Bo Yeon; Kim, Cheorl-Ho

    2007-01-01

    The ganglioside-specific sialidase Neu3 has been suggested to participate in cell growth, migration, and differentiation. Recent reports suggest that sialidase may be involved in intimal thickening, an early stage in the development of atherosclerosis. However, the role of the Neu3 gene in vascular smooth muscle cells (VSMC) responses has not yet been elucidated. To determine whether a Neu3 is able to modulate VSMC growth, the effect of overexpression of the Neu3 gene on cell proliferation was examined. However, the results show that the overexpression of this gene has no effect on DNA synthesis and ERK phosphorylation in cultured VSMC in the presence of TNF-α. Because atherogenic effects need not be limited to proliferation, we decided to examine whether Neu3 exerted inhibitory effects on matrix metalloproteinase-9 (MMP-9) activity in TNF-α-induced VSMC. The expression of the Neu3 gene led to the inhibition of TNF-α-induced matrix metalloproteinase-9 (MMP-9) expression in VSMC as determined by zymography and immunoblot. Furthermore, Neu3 gene expression strongly decreased MMP-9 promoter activity in response to TNF-α. This inhibition was characterized by the down-regulation of MMP-9, which was transcriptionally regulated at NF-κB and activation protein-1 (AP-1) sites in the MMP-9 promoter. These findings suggest that the Neu3 gene represents a physiological modulator of VSMC responses that may contribute to plaque instability in atherosclerosis

  2. Prostate-specific membrane antigen PET imaging and immunohistochemistry in adenoid cystic carcinoma-@]@a preliminary analysis

    Energy Technology Data Exchange (ETDEWEB)

    Klein Nulent, Thomas J.W.; Es, Robert J.J. van [Utrecht Cancer Center, University Medical Center Utrecht, Department of Head and Neck Surgical Oncology, P.O. Box 85500, Utrecht (Netherlands); University Medical Center Utrecht, Department of Oral and Maxillofacial Surgery, Utrecht (Netherlands); Krijger, Gerard C.; Keizer, Bart de [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); Bree, Remco de [Utrecht Cancer Center, University Medical Center Utrecht, Department of Head and Neck Surgical Oncology, P.O. Box 85500, Utrecht (Netherlands); Willems, Stefan M. [University Medical Center Utrecht, Department of Pathology, Utrecht (Netherlands)

    2017-09-15

    Adenoid cystic carcinoma (AdCC) of the head and neck is an uncommon malignant epithelial tumour of the secretory glands. Many patients develop slowly growing local recurrence and/or distant metastasis, for which treatment options are limited. A retrospective analysis of 9 AdCC patients was conducted to analyse the visualization of AdCC on PSMA PET/CT and to investigate the expression of PSMA on primary, recurrent and metastatic AdCC tumour tissue using immunohistochemistry. Local recurrence occurred in six patients and eight developed distant metastasis. All PET/CTs depicted PSMA-ligand uptake. Four PSMA PET/CTs showed suspected residual disease, eight scans depicted uptake in areas suspected of distant metastasis. Median Maximum Standardized Uptake Value (SUV{sub max}) in local recurrent and distant metastatic AdCC was 2.52 (IQR 2.41-5.95) and 4.01 (IQR 2.66-8.71), respectively. All primary tumours showed PSMA expression on immunohistochemistry (5-90% expression), as well as all available specimens of local recurrence and distant metastases. PSMA PET/CT is able to detect and visualize local recurrent and distant metastatic AdCC. PSMA-specific targeting is supported by PSMA expression on immunohistochemistry. (orig.)

  3. Prostate-specific membrane antigen targeted imaging and therapy of prostate cancer using a PSMA inhibitor as a homing ligand.

    Science.gov (United States)

    Kularatne, Sumith A; Wang, Kevin; Santhapuram, Hari-Krishna R; Low, Philip S

    2009-01-01

    Prostate cancer (PCa) is a major cause of mortality and morbidity in Western society today. Current methods for detecting PCa are limited, leaving most early malignancies undiagnosed and sites of metastasis in advanced disease undetected. Major deficiencies also exist in the treatment of PCa, especially metastatic disease. In an effort to improve both detection and therapy of PCa, we have developed a PSMA-targeted ligand that delivers attached imaging and therapeutic agents selectively to PCa cells without targeting normal cells. The PSMA-targeted radioimaging agent (DUPA-(99m)Tc) was found to bind PSMA-positive human PCa cells (LNCaP cell line) with nanomolar affinity (K(D) = 14 nM). Imaging and biodistribution studies revealed that DUPA-(99m)Tc localizes primarily to LNCaP cell tumor xenografts in nu/nu mice (% injected dose/gram = 11.3 at 4 h postinjection; tumor-to-muscle ratio = 75:1). Two PSMA-targeted optical imaging agents (DUPA-FITC and DUPA-rhodamine B) were also shown to efficiently label PCa cells and to internalize and traffic to intracellular endosomes. A PSMA-targeted chemotherapeutic agent (DUPA-TubH) was demonstrated to kill PSMA-positive LNCaP cells in culture (IC(50) = 3 nM) and to eliminate established tumor xenografts in nu/nu mice with no detectable weight loss. Blockade of tumor targeting upon administration of excess PSMA inhibitor (PMPA) and the absence of targeting to PSMA-negative tumors confirmed the specificity of each of the above targeted reagents for PSMA. Tandem use of the imaging and therapeutic agents targeted to the same receptor could allow detection, staging, monitoring, and treatment of PCa with improved accuracy and efficacy.

  4. Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes.

    Directory of Open Access Journals (Sweden)

    Patricia Hingston

    Full Text Available The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA profiling to characterize the bacterium's cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more genes (1.3× were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431 and magnitude (>1,000-fold of differentially expressed genes (>2-fold, p<0.05 in response to cold. A core set of 22 genes was upregulated at all growth phases, including nine genes required for branched-chain fatty acid (BCFA synthesis, the osmolyte transporter genes opuCBCD, and the internalin A and D genes. Genes suppressed at 4°C were largely associated with cobalamin (B12 biosynthesis or the production/export of cell wall components. Antisense transcription accounted for up to 1.6% of total mapped reads with higher levels (2.5× observed at 4°C than 20°C. The greatest number of upregulated antisense transcripts at 4°C occurred in early lag phase, however, at both temperatures, antisense expression levels were highest in late stationary-phase cells. Cold-induced FA membrane changes included a 15% increase in the proportion of BCFAs and a 15% transient increase in unsaturated FAs between lag and exponential phase. These increases probably reduced the membrane phase transition temperature until optimal levels of BCFAs could be produced. Collectively, this research provides new information regarding cold-induced membrane composition changes in L. monocytogenes, the growth-phase dependency of its cold

  5. 18F-DCFBC Prostate-Specific Membrane Antigen-Targeted PET/CT Imaging in Localized Prostate Cancer: Correlation With Multiparametric MRI and Histopathology.

    Science.gov (United States)

    Turkbey, Baris; Mena, Esther; Lindenberg, Liza; Adler, Stephen; Bednarova, Sandra; Berman, Rose; Ton, Anita T; McKinney, Yolanda; Eclarinal, Philip; Hill, Craig; Afari, George; Bhattacharyya, Sibaprasad; Mease, Ronnie C; Merino, Maria J; Jacobs, Paula M; Wood, Bradford J; Pinto, Peter A; Pomper, Martin G; Choyke, Peter L

    2017-10-01

    To assess the ability of (N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-F-fluorobenzyl-L-cysteine) (F-DCFBC), a prostate-specific membrane antigen-targeted PET agent, to detect localized prostate cancer lesions in correlation with multiparametric MRI (mpMRI) and histopathology. This Health Insurance Portability and Accountability Act of 1996-compliant, prospective, institutional review board-approved study included 13 evaluable patients with localized prostate cancer (median age, 62.8 years [range, 51-74 years]; median prostate-specific antigen, 37.5 ng/dL [range, 3.26-216 ng/dL]). Patients underwent mpMRI and F-DCFBC PET/CT within a 3 months' window. Lesions seen on mpMRI were biopsied under transrectal ultrasound/MRI fusion-guided biopsy, or a radical prostatectomy was performed. F-DCFBC PET/CT and mpMRI were evaluated blinded and separately for tumor detection on a lesion basis. For PET image analysis, MRI and F-DCFBC PET images were fused by using software registration; imaging findings were correlated with histology, and uptake of F-DCFBC in tumors was compared with uptake in benign prostatic hyperplasia nodules and normal peripheral zone tissue using the 80% threshold SUVmax. A total of 25 tumor foci (mean size, 1.8 cm; median size, 1.5 cm; range, 0.6-4.7 cm) were histopathologically identified in 13 patients. Sensitivity rates of F-DCFBC PET/CT and mpMRI were 36% and 96%, respectively, for all tumors. For index lesions, the largest tumor with highest Gleason score, sensitivity rates of F-DCFBC PET/CT and mpMRI were 61.5% and 92%, respectively. The average SUVmax for primary prostate cancer was higher (5.8 ± 4.4) than that of benign prostatic hyperplasia nodules (2.1 ± 0.3) or that of normal prostate tissue (2.1 ± 0.4) at 1 hour postinjection (P = 0.0033). The majority of index prostate cancers are detected with F-DCFBC PET/CT, and this may be a prognostic indicator based on uptake and staging. However, for detecting prostate cancer with high sensitivity, it

  6. Specificity and kinetics of alpha-synuclein binding to model membranes determined with fluorescent excited state intramolecular proton transfer (ESIPT) probe.

    Science.gov (United States)

    Shvadchak, Volodymyr V; Falomir-Lockhart, Lisandro J; Yushchenko, Dmytro A; Jovin, Thomas M

    2011-04-15

    Parkinson disease is characterized cytopathologically by the deposition in the midbrain of aggregates composed primarily of the presynaptic neuronal protein α-synuclein (AS). Neurotoxicity is currently attributed to oligomeric microaggregates subjected to oxidative modification and promoting mitochondrial and proteasomal dysfunction. Unphysiological binding to membranes of these and other organelles is presumably involved. In this study, we performed a systematic determination of the influence of charge, phase, curvature, defects, and lipid unsaturation on AS binding to model membranes using a new sensitive solvatochromic fluorescent probe. The interaction of AS with vesicular membranes is fast and reversible. The protein dissociates from neutral membranes upon thermal transition to the liquid disordered phase and transfers to vesicles with higher affinity. The binding of AS to neutral and negatively charged membranes occurs by apparently different mechanisms. Interaction with neutral bilayers requires the presence of membrane defects; binding increases with membrane curvature and rigidity and decreases in the presence of cholesterol. The association with negatively charged membranes is much stronger and much less sensitive to membrane curvature, phase, and cholesterol content. The presence of unsaturated lipids increases binding in all cases. These findings provide insight into the relation between membrane physical properties and AS binding affinity and dynamics that presumably define protein localization in vivo and, thereby, the role of AS in the physiopathology of Parkinson disease.

  7. Protection by meningococcal outer membrane protein PorA-specific antibodies and a serogroup B capsular polysaccharide-specific antibody in complement-sufficient and C6-deficient infant rats.

    Science.gov (United States)

    Toropainen, Maija; Saarinen, Leena; Vidarsson, Gestur; Käyhty, Helena

    2006-05-01

    The relative contributions of antibody-induced complement-mediated bacterial lysis and antibody/complement-mediated phagocytosis to host immunity against meningococcal infections are currently unclear. Further, the in vivo effector functions of antibodies may vary depending on their specificity and Fc heavy-chain isotype. In this study, a mouse immunoglobulin G2a (mIgG2a) monoclonal antibody (MN12H2) to meningococcal outer membrane protein PorA (P1.16), its human IgG subclass derivatives (hIgG1 to hIgG4), and an mIgG2a monoclonal antibody (Nmb735) to serogroup B capsular polysaccharide (B-PS) were evaluated for passive protection against meningococcal serogroup B strain 44/76-SL (B:15:P1.7,16) in an infant rat infection model. Complement component C6-deficient (PVG/c-) rats were used to assess the importance of complement-mediated bacterial lysis for protection. The PorA-specific parental mIgG2a and the hIgG1 to hIgG3 derivatives all induced efficient bactericidal activity in vitro in the presence of human or infant rat complement and augmented bacterial clearance in complement-sufficient HsdBrlHan:WIST rats, while the hIgG4 was unable to do so. In C6-deficient PVG/c- rats, lacking complement-mediated bacterial lysis, the augmentation of bacterial clearance by PorA-specific mIgG2a and hIgG1 antibodies was impaired compared to that in the syngeneic complement-sufficient PVG/c+ rat strain. This was in contrast to the case for B-PS-specific mIgG2a, which conferred similar protective activity in both rat strains. These data suggest that while anti-B-PS antibody can provide protection in the infant rats without membrane attack complex formation, the protection afforded by anti-PorA antibody is more dependent on the activation of the whole complement pathway and subsequent bacterial lysis.

  8. Professional oral hygiene treatment and detailed oral hygiene instructions in patients affected by mucous membrane pemphigoid with specific gingival localization: a pilot study in 12 patients.

    Science.gov (United States)

    Arduino, P G; Lopetuso, E; Carcieri, P; Giacometti, S; Carbone, M; Tanteri, C; Broccoletti, R

    2012-05-01

    The aim of this prospective case series was to assess the clinical efficiency of an oral hygiene protocol in patients affected by mucous membrane pemphigoid (MMP) with specific gingival localization, before starting any medical treatment. Patients received oral hygiene instruction followed by non-surgical periodontal therapy including oral hygiene instructions in a 3-week cohort study. Clinical outcome variables were recorded at baseline and 5 weeks after intervention and included, as periodontal parameters, full mouth plaque (FMPS) and bleeding (FMBS) scores and patient-related outcomes (visual analogue score of pain). A total of 12 patients were recruited. The mean age at presentation was 59.5 ± 14.52 years. Five weeks after finishing the oral hygiene and periodontal therapy protocol, a statistical significant reduction was observed for FMPS (P = 0.001), FMBS (P = 0.022) and reported pain (P = 0.0028). Professional oral hygiene procedures and non-surgical periodontal therapy are connected with improvement of gingival status and decrease in gingival-related pain, in female patients affected by MMP with specific gingival localization. © 2011 John Wiley & Sons A/S.

  9. Updating default depths in the ISC bulletin

    Science.gov (United States)

    Bolton, Maiclaire K.; Storchak, Dmitry A.; Harris, James

    2006-09-01

    The International Seismological Centre (ISC) publishes the definitive global bulletin of earthquake locations. In the ISC bulletin, we aim to obtain a free depth, but often this is not possible. Subsequently, the first option is to obtain a depth derived from depth phases. If depth phases are not available, we then use the reported depth from a reputable local agency. Finally, as a last resort, we set a default depth. In the past, common depths of 10, 33, or multiples of 50 km have been assigned. Assigning a more meaningful default depth, specific to a seismic region will increase the consistency of earthquake locations within the ISC bulletin and allow the ISC to publish better positions and magnitude estimates. It will also improve the association of reported secondary arrivals to corresponding seismic events. We aim to produce a global set of default depths, based on a typical depth for each area, from well-constrained events in the ISC bulletin or where depth could be constrained using a consistent set of depth phase arrivals provided by a number of different reporters. In certain areas, we must resort to using other assumptions. For these cases, we use a global crustal model (Crust2.0) to set default depths to half the thickness of the crust.

  10. Weighted halfspace depth

    Czech Academy of Sciences Publication Activity Database

    Kotík, Lukáš; Hlubinka, D.; Vencálek, O.

    Vol. 46, č. 1 (2010), s. 125-148 ISSN 0023-5954 Institutional research plan: CEZ:AV0Z10750506 Keywords : data depth * nonparametric multivariate analysis * strong consistency of depth * mixture of distributions Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.461, year: 2010 http://library.utia.cas.cz/separaty/2010/SI/kotik-weighted halfspace depth.pdf

  11. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    OpenAIRE

    Jiříček, T.; Komárek, M.; Lederer, T.

    2017-01-01

    Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest ...

  12. 99mTc-labeling and evaluation of a HYNIC modified small-molecular inhibitor of prostate-specific membrane antigen

    International Nuclear Information System (INIS)

    Xu, Xiaoping; Zhang, Jianping; Hu, Silong; He, Simin; Bao, Xiao; Ma, Guang; Luo, Jianmin; Cheng, Jingyi; Zhang, Yingjian

    2017-01-01

    Introduction: Prostate-specific membrane antigen (PSMA) is a well-established target in the development of radiopharmaceuticals for the diagnosis and therapy of prostate cancer (PCa). In this study, we evaluated a novel 99m Tc-labeled small molecular inhibitor of PSMA. Methods: This new small-molecular inhibitor of PSMA, 6-hydrazinonicotinate-Aminocaproic acid-Lysine-Urea-Glutamate (HYNIC-ALUG) was radiolabeled by 99m Tc and was evaluated both in vitro and in vivo using PCa models (PC-3 and LNCaP). Radiation dosimetry was assessed in mice. Results: 99m Tc-HYNIC-ALUG showed excellent stability in different media. A cell assay preliminarily displayed its specificity for PSMA. The inhibitor showed good pharmacokinetics making it suitable for in vivo imaging. PC-3-derived tumors showed no obvious radioactive uptake; however, the LNCaP-derived tumors showed very high radioactive uptake which was significantly decreased by the selective PSMA inhibitor 2-PMPA. Biodistribution in LNCaP xenografts showed an optimum tumor-to-blood ratio of 24.23 ± 3.54 at 2 h. Tumor uptake was also decreased in the inhibition experiment with 2-PMPA (19.45 ± 2.14%ID/g versus 1.42 ± 0.15%ID/g at 2 h). The effective dose of the 99m Tc-HYNIC-ALUG was 8.4E-04 mSv/MBq. Conclusions: A new 99m Tc-labeled PSMA inhibitor with specific accumulation in PSMA-positive tumors and low background in other organs was synthesized. The radiopharmaceutical also showed very low radiation dosimetry. This agent may significantly improve the diagnosis, staging, and subsequent monitoring of therapeutic effects in PCa patients.

  13. Membrane specific drugs as radiosensitizers

    Energy Technology Data Exchange (ETDEWEB)

    George, K.C.; Mishra, K.P.; Shenoy, M.A.; Singh, B.B.; Srinivasan, V.T.; Verma, N.C.

    1981-01-01

    Procaine, paracetamol, and chlorpromazine showed inhibition of post irradiation repair. The chlorpromazie effect could be further augmented by treatment of cells with procaine. Chlorpromazine was also found to be preferentially toxic to hypoxid bacterial cells, and the survivors showed extreme radiosensitivity to gamma rays. Chlorpromazine was found to inhibit tumour growth in swiss mice when given intraperitoneally as well as when injected directly into the tumour. When combined with single x-ray doses, significant radiosensitization was observed in two in vivo tumours sarcoma 180A and fibrosarcoma. These results indicated that chlorpromazine may prove a good drug for combined chemo-radiotherapy of solid tumours. Investigations continued studying various aspects such as effectiveness in other tumour lines, distribution in healthy and tumour bearing animals, hyperthermia and drug combination effects, and encapsulation of the drug in artificial liposomes and blood cells. (ERB)

  14. Clustering on Membranes

    DEFF Research Database (Denmark)

    Johannes, Ludger; Pezeshkian, Weria; Ipsen, John H

    2018-01-01

    Clustering of extracellular ligands and proteins on the plasma membrane is required to perform specific cellular functions, such as signaling and endocytosis. Attractive forces that originate in perturbations of the membrane's physical properties contribute to this clustering, in addition to direct...... protein-protein interactions. However, these membrane-mediated forces have not all been equally considered, despite their importance. In this review, we describe how line tension, lipid depletion, and membrane curvature contribute to membrane-mediated clustering. Additional attractive forces that arise...... from protein-induced perturbation of a membrane's fluctuations are also described. This review aims to provide a survey of the current understanding of membrane-mediated clustering and how this supports precise biological functions....

  15. MacA, a periplasmic membrane fusion protein of the macrolide transporter MacAB-TolC, binds lipopolysaccharide core specifically and with high affinity.

    Science.gov (United States)

    Lu, Shuo; Zgurskaya, Helen I

    2013-11-01

    The Escherichia coli MacAB-TolC transporter has been implicated in efflux of macrolide antibiotics and secretion of enterotoxin STII. In this study, we found that purified MacA, a periplasmic membrane fusion protein, contains one tightly bound rough core lipopolysaccharide (R-LPS) molecule per MacA molecule. R-LPS was bound specifically to MacA protein with affinity exceeding that of polymyxin B. Sequence analyses showed that MacA contains two high-density clusters of positively charged amino acid residues located in the cytoplasmic N-terminal domain and the periplasmic C-terminal domain. Substitutions in the C-terminal cluster reducing the positive-charge density completely abolished binding of R-LPS. At the same time, these substitutions significantly reduced the functionality of MacA in the protection of E. coli against macrolides in vivo and in the in vitro MacB ATPase stimulation assays. Taken together, our results suggest that R-LPS or a similar glycolipid is a physiological substrate of MacAB-TolC.

  16. Osteoblast cell membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry for screening specific active components from traditional Chinese medicines.

    Science.gov (United States)

    Wang, Nani; Zhang, Qiaoyan; Xin, Hailiang; Shou, Dan; Qin, Luping

    2017-11-01

    A method using osteoblast membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry was developed to recognize and identify the specific active components from traditional Chinese medicines. Primary rat osteoblasts were used for the preparation of the stationary phase in the cell chromatography method. Retention components from the cell chromatography were collected and analyzed by liquid chromatography with time-of-flight mass spectrometry. This method was applied in screening active components from extracts of four traditional Chinese medicines. In total, 24 potentially active components with different structures were retained by osteoblast cell chromatography. There were five phenolic glucosides and one triterpenoid saponin from Curculigo orchioides Gaertn, two organic acids and ten flavonoids from Epimedium sagittatum Maxim, one phthalide compound and one organic acid from Angelica sinensis Diels, and two flavonoids and two saponins from Anemarrhena asphodeloides Bunge. Among those, four components (icariin, curculigoside, ferulaic acid, and timosaponin BII) were used for in vitro pharmacodynamics validation. They significantly increased the osteoblast proliferation, alkaline phosphatase activity, levels of bone gla protein and collagen type 1, and promoted mineralized nodule formation. The developed method was an effective screening method for finding active components from complex medicines that act on bone diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Quantitative characterisation of clinically significant intra-prostatic cancer by prostate-specific membrane antigen (PSMA) expression and cell density on PSMA-11.

    Science.gov (United States)

    Domachevsky, Liran; Goldberg, Natalia; Bernstine, Hanna; Nidam, Meital; Groshar, David

    2018-05-30

    To quantitatively characterize clinically significant intra-prostatic cancer (IPC) by prostate-specific membrane antigen (PSMA) expression and cell density on PSMA-11 positron emission tomography/magnetic resonance (PET/MR). Retrospective study approved by the institutional review board with informed written consent obtained. Patients with a solitary, biopsy-proven prostate cancer, Gleason score (GS) ≥7, presenting for initial evaluation by PET/computerised tomography (PET/CT), underwent early prostate PET/MR immediately after PSMA-11 tracer injection. PET/MR [MRI-based attenuation correction (MRAC)] and PET/CT [CT-based AC (CTAC)] maximal standardised uptake value (SUVmax) and minimal and mean apparent diffusion coefficient (ADCmin, ADCmean; respectively) in normal prostatic tissue (NPT) were compared to IPC area. The relationship between SUVmax, ADCmin and ADCmean measurements was obtained. Twenty-two patients (mean age 69.5±5.0 years) were included in the analysis. Forty-four prostate areas were evaluated (22 IPC and 22 NPT). Median MRAC SUVmax of NPT was significantly lower than median MRAC SUVmax of IPC (p prostate cancer patients with GS ≥ 7. • PSMA PET/MR metrics differentiate between normal and tumoural prostatic tissue. • A multi-parametric approach combining molecular and anatomical information might direct prostate biopsy. • PSMA PET/MR metrics are warranted for radiomics analysis.

  18. Glycolipid precursors for the membrane anchor of Trypanosoma brucei variant surface glycoproteins. II. Lipid structures of phosphatidylinositol-specific phospholipase C sensitive and resistant glycolipids

    International Nuclear Information System (INIS)

    Mayor, S.; Menon, A.K.; Cross, G.A.

    1990-01-01

    A common diagnostic feature of glycosylinositol phospholipid (GPI)-anchored proteins is their release from the membrane by a phosphatidylinositol-specific phospholipase C (PI-PLC). However, some GPI-anchored proteins are resistant to this enzyme. The best characterized example of this subclass is the human erythrocyte acetylcholinesterase, where the structural basis of PI-PLC resistance has been shown to be the acylation of an inositol hydroxyl group(s). Both PI-PLC-sensitive and resistant GPI-anchor precursors (P2 and P3, respectively) have been found in Trypanosoma brucei, where the major surface glycoprotein is anchored by a PI-PLC-sensitive glycolipid anchor. The accompanying paper shows that P2 and P3 have identical glycans, indistinguishable from the common core glycan found on all the characterized GPI protein anchors. This paper shows that the single difference between P2 and P3, and the basis for the PI-PLC insusceptibility of P3, is a fatty acid, ester-linked to the inositol residue in P3. The inositol-linked fatty acid can be removed by treatment with mild base to restore PI-PLC sensitivity. Biosynthetic labeling experiments with [3H]palmitic acid and [3H]myristic acid show that [3H]palmitic acid specifically labels the inositol residue in P3 while [3H]myristic acid labels the diacylglycerol portion. Possible models to account for the simultaneous presence of PI-PLC-resistant and sensitive glycolipids are discussed in the context of available information on the biosynthesis of GPI-anchors

  19. Phase I trial of yttrium-90-labeled anti-prostate-specific membrane antigen monoclonal antibody J591 for androgen-independent prostate cancer.

    Science.gov (United States)

    Milowsky, Matthew I; Nanus, David M; Kostakoglu, Lale; Vallabhajosula, Shankar; Goldsmith, Stanley J; Bander, Neil H

    2004-07-01

    To determine the maximum-tolerated dose (MTD), toxicity, human antihuman antibody (HAHA) response, pharmacokinetics, organ dosimetry, targeting, and preliminary efficacy of yttrium-90-labeled anti-prostate-specific membrane antigen monoclonal antibody J591 ((90)Y-J591) in patients with androgen-independent prostate cancer (PC). Patients with androgen-independent PC and evidence of disease progression received indium-111-J591 for pharmacokinetic and biodistribution determinations followed 1 week later by (90)Y-J591 at five dose levels: 5, 10, 15, 17.5, and 20 mCi/m(2). Patients were eligible for up to three re-treatments if platelet and neutrophil recovery was satisfactory. Twenty-nine patients with androgen-independent PC received (90)Y-J591, four of whom were re-treated. Dose limiting toxicity (DLT) was seen at 20 mCi/m(2), with two patients experiencing thrombocytopenia with non-life-threatening bleeding episodes requiring platelet transfusions. The 17.5-mCi/m(2) dose level was determined to be the MTD. No re-treated patients experienced DLT. Nonhematologic toxicity was not dose limiting. Targeting of known sites of bone and soft tissue metastases was seen in the majority of patients. No HAHA response was seen. Antitumor activity was seen, with two patients experiencing 85% and 70% declines in prostate-specific antigen (PSA) levels lasting 8 and 8.6 months, respectively, before returning to baseline. Both patients had objective measurable disease responses. An additional six patients (21%) experienced PSA stabilization. The recommended dose for (90)Y-J591 is 17.5 mCi/m(2). Acceptable toxicity, excellent targeting of known sites of PC metastases, and biologic activity in patients with androgen-independent PC warrant further investigation of (90)Y-J591 in the treatment of patients with PC.

  20. Follicle-stimulating hormone (FSH) unmasks specific high affinity FSH-binding sites in cell-free membrane preparations of porcine granulosa cells

    Energy Technology Data Exchange (ETDEWEB)

    Ford, K.A.; LaBarbera, A.R.

    1988-11-01

    The purpose of these studies was to determine whether changes in FSH receptors correlated with FSH-induced attenuation of FSH-responsive adenylyl cyclase in immature porcine granulosa cells. Cells were incubated with FSH (1-1000 ng/ml) for up to 24 h, treated with acidified medium (pH 3.5) to remove FSH bound to cells, and incubated with (125I)iodo-porcine FSH to quantify FSH-binding sites. FSH increased binding of FSH in a time-, temperature-, and FSH concentration-dependent manner. FSH (200 ng/ml) increased binding approximately 4-fold within 16 h. Analysis of equilibrium saturation binding data indicated that the increase in binding sites reflected a 2.3-fold increase in receptor number and a 5.4-fold increase in apparent affinity. The increase in binding did not appear to be due to 1) a decrease in receptor turnover, since the basal rate of turnover appeared to be very slow; 2) an increase in receptor synthesis, since agents that inhibit protein synthesis and glycosylation did not block the increase in binding; or 3) an increase in intracellular receptors, since agents that inhibit cytoskeletal components had no effect. Agents that increase intracellular cAMP did not affect FSH binding. The increase in binding appeared to result from unmasking of cryptic FSH-binding sites, since FSH increased binding in cell-free membrane preparations to the same extent as in cells. Unmasking of cryptic sites was hormone specific, and the sites bound FSH specifically. Unmasking of sites was reversible in a time- and temperature-dependent manner after removal of bound FSH. The similarity between the FSH dose-response relationships for unmasking of FSH-binding sites and attenuation of FSH-responsive cAMP production suggests that the two processes are functionally linked.

  1. Cardiac-specific inducible overexpression of human plasma membrane Ca2+ ATPase 4b is cardioprotective and improves survival in mice following ischemic injury.

    Science.gov (United States)

    Sadi, Al Muktafi; Afroze, Talat; Siraj, M Ahsan; Momen, Abdul; White-Dzuro, Colin; Zarrin-Khat, Dorrin; Handa, Shivalika; Ban, Kiwon; Kabir, M Golam; Trivieri, Maria G; Gros, Robert; Backx, Peter; Husain, Mansoor

    2018-03-30

    Background: Heart failure (HF) is associated with reduced expression of plasma membrane Ca 2+ -ATPase 4 (PMCA4). Cardiac-specific overexpression of human PMCA4b in mice inhibited nNOS activity and reduced cardiac hypertrophy by inhibiting calcineurin. Here we examine temporally regulated cardiac-specific overexpression of hPMCA4b in mouse models of myocardial ischemia reperfusion injury (IRI) ex vivo , and HF following experimental myocardial infarction (MI) in vivo Methods and results: Doxycycline-regulated cardiomyocyte-specific overexpression and activity of hPMCA4b produced adaptive changes in expression levels of Ca 2+ -regulatory genes, and induced hypertrophy without significant differences in Ca 2+ transients or diastolic Ca 2+ concentrations. Total cardiac NOS and nNOS-specific activities were reduced in mice with cardiac overexpression of hPMCA4b while nNOS, eNOS and iNOS protein levels did not differ. hMPCA4b-overexpressing mice also exhibited elevated systolic blood pressure vs. controls, with increased contractility and lusitropy in vivo In isolated hearts undergoing IRI, hPMCA4b overexpression was cardioprotective. NO donor-treated hearts overexpressing hPMCA4b showed reduced LVDP and larger infarct size versus vehicle-treated hearts undergoing IRI, demonstrating that the cardioprotective benefits of hPMCA4b-repressed nNOS are lost by restoring NO availability. Finally, both pre-existing and post-MI induction of hPMCA4b overexpression reduced infarct expansion and improved survival from HF. Conclusions: Cardiac PMCA4b regulates nNOS activity, cardiac mass and contractility, such that PMCA4b overexpression preserves cardiac function following IRI, heightens cardiac performance and limits infarct progression, cardiac hypertrophy and HF, even when induced late post-MI. These data identify PMCA4b as a novel therapeutic target for IRI and HF. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  2. Development of a Novel, Ultra-rapid Biosensor for the Qualitative Detection of Hepatitis B Virus-associated Antigens and Anti-HBV, Based on “Membrane-engineered” Fibroblast Cells with Virus-Specific Antibodies and Antigens

    Directory of Open Access Journals (Sweden)

    Antonios Perdikaris

    2009-03-01

    Full Text Available A novel miniature cell biosensor detection system for the detection of Hepatis B virus (HBV-associated antigens and anti-HBV is described. The biosensor is based on “membrane-engineered” Vero fibroblast cells immobilized in an alginate matrix. The membrane-engineering process involved the electroinsertion of anti-HBV specific antibodies (anti-HBs, anti-HBe or antigens (HBsAg in the membranes of the Vero cells. The attachment of a homologous antigen to the electroinserted antibody (or, respectively, of the antibody to the electroinserted antigen triggered specific changes to the cell membrane potential that were measured by appropriate microelectrodes, according to the principle of the Bioelectric Recognition Assay (BERA. The sensor was used for screening 133 clinical blood serum samples according to a double-blind protocol. Considerably higher sensor responses were observed against HBV-positive samples, compared with responses against negative samples or samples positive for heterologous hepatitis viruses such as Hepatitis C (HCV virus. Detection of anti-HBs antibodies was made possible by using a biosensor based on immobilized Vero cells bearing the respective antigen (HBsAg. The observed response was rapid (45 sec and quite reproducible. Fluorescence microscopy observations showed that attachment of HBV particles to cells membrane-engineered with anti-HBs was associated with a decrease of [Ca2+]cyt. The perspectives for using the novel biosensor as a qualitative, rapid screening, high throughput assay for HBV antigens and anti-HBs in clinical samples is discussed.

  3. Complexity and Dynamical Depth

    Directory of Open Access Journals (Sweden)

    Terrence Deacon

    2014-07-01

    Full Text Available We argue that a critical difference distinguishing machines from organisms and computers from brains is not complexity in a structural sense, but a difference in dynamical organization that is not well accounted for by current complexity measures. We propose a measure of the complexity of a system that is largely orthogonal to computational, information theoretic, or thermodynamic conceptions of structural complexity. What we call a system’s dynamical depth is a separate dimension of system complexity that measures the degree to which it exhibits discrete levels of nonlinear dynamical organization in which successive levels are distinguished by local entropy reduction and constraint generation. A system with greater dynamical depth than another consists of a greater number of such nested dynamical levels. Thus, a mechanical or linear thermodynamic system has less dynamical depth than an inorganic self-organized system, which has less dynamical depth than a living system. Including an assessment of dynamical depth can provide a more precise and systematic account of the fundamental difference between inorganic systems (low dynamical depth and living systems (high dynamical depth, irrespective of the number of their parts and the causal relations between them.

  4. Motivation with Depth.

    Science.gov (United States)

    DiSpezio, Michael A.

    2000-01-01

    Presents an illusional arena by offering experience in optical illusions in which students must apply critical analysis to their innate information gathering systems. Introduces different types of depth illusions for students to experience. (ASK)

  5. Preclinical evaluation of BAY 1075553, a novel 18F-labelled inhibitor of prostate-specific membrane antigen for PET imaging of prostate cancer

    International Nuclear Information System (INIS)

    Lesche, Ralf; Kettschau, Georg; Gromov, Alexey V.; Boehnke, Niels; Borkowski, Sandra; Moenning, Ursula; Doehr, Olaf; Graham, Keith; Hegele-Hartung, Christa; Dinkelborg, Ludger M.

    2014-01-01

    Prostate-specific membrane antigen (PSMA) is a transmembrane protein overexpressed in prostate cancer and is therefore being explored as a biomarker for diagnosing and staging of the disease. Here we report preclinical data on BAY 1075553 (a 9:1 mixture of (2S,4S)- and (2R,4S)-2-[ 18 F]fluoro-4-phosphonomethyl-pentanedioic acid), a novel 18 F-labelled small molecule inhibitor of PSMA enzymatic activity, which can be efficiently synthesized from a direct radiolabelling precursor. The 18 F-radiolabelled stereoisomers of 2-[ 18 F]fluoro-4-(phosphonomethyl)-pentanedioic acid were synthesized from their respective isomerically pure precursors dimethyl 2-{[bis(benzyloxy)phosphoryl ]methyl}-4-(tosyloxy)pentanedioate. In vivo positron emission tomography (PET) imaging and biodistribution studies were conducted in mice bearing LNCaP, 22Rv1 and PC-3 tumours. Pharmacokinetic parameters and dosimetry estimates were calculated based on biodistribution studies in rodents. For non-clinical safety assessment (safety pharmacology, toxicology) to support a single-dose human microdose study, off-target effects in vitro, effects on vital organ functions (cardiovascular in dogs, nervous system in rats), mutagenicity screens and an extended single-dose study in rats were conducted with the non-radioactive racemic analogue of BAY 1075553. BAY 1075553 showed high tumour accumulation specific to PSMA-positive tumour-bearing mice and was superior to other stereoisomers tested. Fast clearance of BAY 1075553 resulted overall in low background signals in other organs except for high uptake into kidney and bladder which was mainly caused by renal elimination of BAY 1075553. A modest uptake into bone was observed which decreased over time indicating organ-specific uptake as opposed to defluorination of BAY 1075553 in vivo. Biodistribution studies found highest organ doses for kidneys and the urinary bladder wall resulting in a projected effective dose (ED) in humans of 0.0219 mSv/MBq. Non

  6. Preclinical evaluation of BAY 1075553, a novel {sup 18}F-labelled inhibitor of prostate-specific membrane antigen for PET imaging of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lesche, Ralf; Kettschau, Georg; Gromov, Alexey V.; Boehnke, Niels; Borkowski, Sandra; Moenning, Ursula; Doehr, Olaf; Graham, Keith [Global Drug Discovery, Bayer Healthcare, Berlin, Germany, Berlin (Germany); Hegele-Hartung, Christa [Global Drug Discovery, Bayer Healthcare, Wuppertal, Germany, Wuppertal (Germany); Dinkelborg, Ludger M. [Global Drug Discovery, Bayer Healthcare, Berlin, Germany, Berlin (Germany); Piramal Imaging GmbH, Berlin (Germany)

    2014-01-15

    Prostate-specific membrane antigen (PSMA) is a transmembrane protein overexpressed in prostate cancer and is therefore being explored as a biomarker for diagnosing and staging of the disease. Here we report preclinical data on BAY 1075553 (a 9:1 mixture of (2S,4S)- and (2R,4S)-2-[{sup 18}F]fluoro-4-phosphonomethyl-pentanedioic acid), a novel {sup 18}F-labelled small molecule inhibitor of PSMA enzymatic activity, which can be efficiently synthesized from a direct radiolabelling precursor. The {sup 18}F-radiolabelled stereoisomers of 2-[{sup 18}F]fluoro-4-(phosphonomethyl)-pentanedioic acid were synthesized from their respective isomerically pure precursors dimethyl 2-{[bis(benzyloxy)phosphoryl ]methyl}-4-(tosyloxy)pentanedioate. In vivo positron emission tomography (PET) imaging and biodistribution studies were conducted in mice bearing LNCaP, 22Rv1 and PC-3 tumours. Pharmacokinetic parameters and dosimetry estimates were calculated based on biodistribution studies in rodents. For non-clinical safety assessment (safety pharmacology, toxicology) to support a single-dose human microdose study, off-target effects in vitro, effects on vital organ functions (cardiovascular in dogs, nervous system in rats), mutagenicity screens and an extended single-dose study in rats were conducted with the non-radioactive racemic analogue of BAY 1075553. BAY 1075553 showed high tumour accumulation specific to PSMA-positive tumour-bearing mice and was superior to other stereoisomers tested. Fast clearance of BAY 1075553 resulted overall in low background signals in other organs except for high uptake into kidney and bladder which was mainly caused by renal elimination of BAY 1075553. A modest uptake into bone was observed which decreased over time indicating organ-specific uptake as opposed to defluorination of BAY 1075553 in vivo. Biodistribution studies found highest organ doses for kidneys and the urinary bladder wall resulting in a projected effective dose (ED) in humans of 0.0219 m

  7. Stability of transmembrane amyloid β-peptide and membrane integrity tested by molecular modeling of site-specific Aβ42 mutations.

    Directory of Open Access Journals (Sweden)

    Chetan Poojari

    Full Text Available Interactions of the amyloid β-protein (Aβ with neuronal cell membranes, leading to the disruption of membrane integrity, are considered to play a key role in the development of Alzheimer's disease. Natural mutations in Aβ42, such as the Arctic mutation (E22G have been shown to increase Aβ42 aggregation and neurotoxicity, leading to the early-onset of Alzheimer's disease. A correlation between the propensity of Aβ42 to form protofibrils and its effect on neuronal dysfunction and degeneration has been established. Using rational mutagenesis of the Aβ42 peptide it was further revealed that the aggregation of different Aβ42 mutants in lipid membranes results in a variety of polymorphic aggregates in a mutation dependent manner. The mutant peptides also have a variable ability to disrupt bilayer integrity. To further test the connection between Aβ42 mutation and peptide-membrane interactions, we perform molecular dynamics simulations of membrane-inserted Aβ42 variants (wild-type and E22G, D23G, E22G/D23G, K16M/K28M and K16M/E22G/D23G/K28M mutants as β-sheet monomers and tetramers. The effects of charged residues on transmembrane Aβ42 stability and membrane integrity are analyzed at atomistic level. We observe an increased stability for the E22G Aβ42 peptide and a decreased stability for D23G compared to wild-type Aβ42, while D23G has the largest membrane-disruptive effect. These results support the experimental observation that the altered toxicity arising from mutations in Aβ is not only a result of the altered aggregation propensity, but also originates from modified Aβ interactions with neuronal membranes.

  8. Development of (99m)Tc-labeled asymmetric urea derivatives that target prostate-specific membrane antigen for single-photon emission computed tomography imaging.

    Science.gov (United States)

    Kimura, Hiroyuki; Sampei, Sotaro; Matsuoka, Daiko; Harada, Naoya; Watanabe, Hiroyuki; Arimitsu, Kenji; Ono, Masahiro; Saji, Hideo

    2016-05-15

    Prostate-specific membrane antigen (PSMA) is expressed strongly in prostate cancers and is, therefore, an attractive diagnostic and radioimmunotherapeutic target. In contrast to previous reports of PMSA-targeting (99m)Tc-tricarbonyl complexes that are cationic or lack a charge, no anionic (99m)Tc-tricarbonyl complexes have been reported. Notably, the hydrophilicity conferred by both cationic and anionic charges leads to rapid hepatobiliary clearance, whereas an anionic charge might better enhance renal clearance relative to a cationic charge. Therefore, an improvement in rapid clearance would be expected with either cationic or anionic charges, particularly anionic charges. In this study, we designed and synthesized a novel anionic (99m)Tc-tricarbonyl complex ([(99m)Tc]TMCE) and evaluated its use as a single-photon emission computed tomography (SPECT) imaging probe for PSMA detection. Direct synthesis of [(99m)Tc]TMCE from dimethyl iminodiacetate, which contains both the asymmetric urea and succinimidyl moiety important for PSMA binding, was performed using our microwave-assisted one-pot procedure. The chelate formation was successfully achieved even though the precursor included a complicated bioactive moiety. The radiochemical yield of [(99m)Tc]TMCE was 12-17%, with a radiochemical purity greater than 98% after HPLC purification. [(99m)Tc]TMCE showed high affinity in vitro, with high accumulation in LNCaP tumors and low hepatic retention in biodistribution and SPECT/CT studies. These findings warrant further evaluation of [(99m)Tc]TMCE as an imaging agent and support the benefit of this strategy for the design of other PSMA imaging probes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The Instrumentation of a Microfluidic Analyzer Enabling the Characterization of the Specific Membrane Capacitance, Cytoplasm Conductivity, and Instantaneous Young's Modulus of Single Cells.

    Science.gov (United States)

    Wang, Ke; Zhao, Yang; Chen, Deyong; Huang, Chengjun; Fan, Beiyuan; Long, Rong; Hsieh, Chia-Hsun; Wang, Junbo; Wu, Min-Hsien; Chen, Jian

    2017-06-19

    This paper presents the instrumentation of a microfluidic analyzer enabling the characterization of single-cell biophysical properties, which includes seven key components: a microfluidic module, a pressure module, an imaging module, an impedance module, two LabVIEW platforms for instrument operation and raw data processing, respectively, and a Python code for data translation. Under the control of the LabVIEW platform for instrument operation, the pressure module flushes single cells into the microfluidic module with raw biophysical parameters sampled by the imaging and impedance modules and processed by the LabVIEW platform for raw data processing, which were further translated into intrinsic cellular biophysical parameters using the code developed in Python. Based on this system, specific membrane capacitance, cytoplasm conductivity, and instantaneous Young's modulus of three cell types were quantified as 2.76 ± 0.57 μF/cm², 1.00 ± 0.14 S/m, and 3.79 ± 1.11 kPa for A549 cells ( n cell = 202); 1.88 ± 0.31 μF/cm², 1.05 ± 0.16 S/m, and 3.74 ± 0.75 kPa for 95D cells ( n cell = 257); 2.11 ± 0.38 μF/cm², 0.87 ± 0.11 S/m, and 5.39 ± 0.89 kPa for H460 cells ( n cell = 246). As a semi-automatic instrument with a throughput of roughly 1 cell per second, this prototype instrument can be potentially used for the characterization of cellular biophysical properties.

  10. Radiolabeling of anti-human prostatic specific membrane antigen antibody with 99Tcm and its biodistribution in nude mice bearing human prostate cancer

    International Nuclear Information System (INIS)

    Tu Shaohua; Shen Jiangfan; Tao Rong; Ji Xiaowen; Wang Yancheng

    2012-01-01

    Objective: To study the binding affinity of 99 Tc m labeled anti-human prostatic specific membrane antigen (PSMA) monoclonal antibody (McAb) J591 to prostate cancer cells and the biodistribution of 99 Tc m -J591 in nude mice bearing human prostate cancer. Methods: The McAb J591 was labeled with vTcm by improved Schwarz method and the labeled McAb was purified by Sephadex G-50. The binding affinity of J591 with prostate cancer cells was measured by Flow Cytometry. The nude mice bearing PSMA-positive C4-2 prostate carcinoma xenografts were served as experiment groups, mice with PSMA-negative pc3 tumors served as controls. The biodistribution of 99 Tc m -J591 were carried out in both model nude mice. Results: The radiolabeling efficiency of 99 Tc m -J591 was 78.9±6.2%, and radiochemical purity was more than 90% after purification. The 99 Tc m -J591 showed a good combination with PSMA-positive C4-2 cells and no combination with PSMA-negative PC3 cells in vitro. The biodistribution results showed that 99 Tcm-J591 was accumulated in tumor tissue during the 2-24 hours after injection in experiment groups, and no significant uptake in control group. The uptake of 99 Tcm-J591 in tumor tissue reached a maximum 15.91±5.16 % ID/g in experimental group at 12h post-injection. There was a significant difference compared with controls (P 0.05). Conclusion: The monoclonal antibody J591 exhibits an excellent immuno-reactivity and tumor targeting property, and it may be used in diagnosis and target therapy of prostate cancer. (authors)

  11. Membrane fusion

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  12. Directional Joint Bilateral Filter for Depth Images

    Directory of Open Access Journals (Sweden)

    Anh Vu Le

    2014-06-01

    Full Text Available Depth maps taken by the low cost Kinect sensor are often noisy and incomplete. Thus, post-processing for obtaining reliable depth maps is necessary for advanced image and video applications such as object recognition and multi-view rendering. In this paper, we propose adaptive directional filters that fill the holes and suppress the noise in depth maps. Specifically, novel filters whose window shapes are adaptively adjusted based on the edge direction of the color image are presented. Experimental results show that our method yields higher quality filtered depth maps than other existing methods, especially at the edge boundaries.

  13. Gas separation with membranes

    International Nuclear Information System (INIS)

    Schulz, G.; Michele, H.; Werner, U.

    1982-01-01

    Gas separation with membranes has already been tested in numerous fields of application, e.g. uranium enrichment of H 2 separation. In many of these processes the mass transfer units, so-called permeators, have to be connected in tandem in order to achieve high concentrations. A most economical operating method provides for each case an optimization of the cascades with regard to the membrane materials, construction and design of module. By utilization of the concentration gradient along the membrane a new process development has been accomplished - the continuously operating membrane rectification unit. Investment and operating costs can be reduced considerably for a number of separating processes by combining a membrane rectification unit with a conventional recycling cascade. However, the new procedure requires that the specifications for the module construction, flow design, and membrane properties be reconsidered. (orig.) [de

  14. A novel Geobacteraceae-specific outer membrane protein J (OmpJ is essential for electron transport to Fe (III and Mn (IV oxides in Geobacter sulfurreducens

    Directory of Open Access Journals (Sweden)

    Schiffer Marianne

    2005-07-01

    Full Text Available Abstract Background Metal reduction is thought to take place at or near the bacterial outer membrane and, thus, outer membrane proteins in the model dissimilatory metal-reducing organism Geobacter sulfurreducens are of interest to understand the mechanisms of Fe(III reduction in the Geobacter species that are the predominant Fe(III reducers in many environments. Previous studies have implicated periplasmic and outer membrane cytochromes in electron transfer to metals. Here we show that the most abundant outer membrane protein of G. sulfurreducens, OmpJ, is not a cytochrome yet it is required for metal respiration. Results When outer membrane proteins of G. sulfurreducens were separated via SDS-PAGE, one protein, designated OmpJ (outer membrane protein J, was particularly abundant. The encoding gene, which was identified from mass spectrometry analysis of peptide fragments, is present in other Geobacteraceae, but not in organisms outside this family. The predicted localization and structure of the OmpJ protein suggested that it was a porin. Deletion of the ompJ gene in G. sulfurreducens produced a strain that grew as well as the wild-type strain with fumarate as the electron acceptor but could not grow with metals, such as soluble or insoluble Fe (III and insoluble Mn (IV oxide, as the electron acceptor. The heme c content in the mutant strain was ca. 50% of the wild-type and there was a widespread loss of multiple cytochromes from soluble and membrane fractions. Transmission electron microscopy analyses of mutant cells revealed an unusually enlarged periplasm, which is likely to trigger extracytoplasmic stress response mechanisms leading to the degradation of periplasmic and/or outer membrane proteins, such as cytochromes, required for metal reduction. Thus, the loss of the capacity for extracellular electron transport in the mutant could be due to the missing c-type cytochromes, or some more direct, but as yet unknown, role of OmpJ in metal

  15. Prestack depth migration

    International Nuclear Information System (INIS)

    Postma, R.W.

    1991-01-01

    Two lines form the southern North Sea, with known velocity inhomogeneities in the overburden, have been pre-stack depth migrated. The pre-stack depth migrations are compared with conventional processing, one with severe distortions and one with subtle distortions on the conventionally processed sections. The line with subtle distortions is also compared with post-stack depth migration. The results on both lines were very successful. Both have already influenced drilling decisions, and have caused a modification of structural interpretation in the respective areas. Wells have been drilled on each of the lines, and well tops confirm the results. In fact, conventional processing led to incorrect locations for the wells, both of which were dry holes. The depth migrated sections indicate the incorrect placement, and on one line reveals a much better drilling location. This paper reports that even though processing costs are high for pre-stack depth migration, appropriate use can save millions of dollars in dry-hole expense

  16. Flow and fouling in membrane filters: Effects of membrane morphology

    Science.gov (United States)

    Sanaei, Pejman; Cummings, Linda J.

    2015-11-01

    Membrane filters are widely-used in microfiltration applications. Many types of filter membranes are produced commercially, for different filtration applications, but broadly speaking the requirements are to achieve fine control of separation, with low power consumption. The answer to this problem might seem obvious: select the membrane with the largest pore size and void fraction consistent with the separation requirements. However, membrane fouling (an inevitable consequence of successful filtration) is a complicated process, which depends on many parameters other than membrane pore size and void fraction; and which itself greatly affects the filtration process and membrane functionality. In this work we formulate mathematical models that can (i) account for the membrane internal morphology (internal structure, pore size & shape, etc.); (ii) fouling of membranes with specific morphology; and (iii) make some predictions as to what type of membrane morphology might offer optimum filtration performance.

  17. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2017-01-01

    Full Text Available Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest flux was achieved with the thinnest membranes and the best energy efficiency was achieved with the thickest membranes. All membranes had salt retention above 99%. Nanotechnology offers the potential to find modern solutions for desalination of waste waters, by introducing new materials with revolutionary properties, but new membranes must be developed according to the target application.

  18. Radio-chemical applications of functionalized membranes

    International Nuclear Information System (INIS)

    Pandey, Ashok K.

    2011-01-01

    Functionalized polymer membranes have many potential applications as they are task specific. We have developed many functionalized membranes like polymer inclusion membranes, pore-filled membranes and nano-membranes. Radiotracers and other methods have been used to understand the diffusional-transport properties of the Nafion-117 membrane as well as home-made membranes. These membranes have been used to develop novel analytical and separation methods for toxic metal ions and radionuclides. In this talk, an overview of our work on functionalized membrane is presented. (author)

  19. Radon depth migration

    International Nuclear Information System (INIS)

    Hildebrand, S.T.; Carroll, R.J.

    1993-01-01

    A depth migration method is presented that used Radon-transformed common-source seismograms as input. It is shown that the Radon depth migration method can be extended to spatially varying velocity depth models by using asymptotic ray theory (ART) to construct wavefield continuation operators. These operators downward continue an incident receiver-array plane wave and an assumed point-source wavefield into the subsurface. The migration velocity model is constrain to have longer characteristic wavelengths than the dominant source wavelength such that the ART approximations for the continuation operators are valid. This method is used successfully to migrate two synthetic data examples: (1) a point diffractor, and (2) a dipping layer and syncline interface model. It is shown that the Radon migration method has a computational advantage over the standard Kirchhoff migration method in that fewer rays are computed in a main memory implementation

  20. Measuring depth in boreholes

    International Nuclear Information System (INIS)

    Hodson, G.M.

    1979-01-01

    This invention relates to a method of determining the depth of rock strata and other features of a borehole. It may be employed with particular advantage when access to the top of the borehole is difficult, for example in underwater operations. A radioactive marker, such as a source of gamma rays, is positioned near the top of the riser of a sub-sea wellhead structure. A radiation detector is lowered between the marker and a radioactive stratum and the length of line supplied is measured on the floating platform. This enables the depth of the stratum to be measured irrespective of tidal variations of the height of the platform. (U.K.)

  1. Deep sequencing of the viral phoH gene reveals temporal variation, depth-specific composition, and persistent dominance of the same viral phoH genes in the Sargasso Sea

    Directory of Open Access Journals (Sweden)

    Dawn B. Goldsmith

    2015-06-01

    Full Text Available Deep sequencing of the viral phoH gene, a host-derived auxiliary metabolic gene, was used to track viral diversity throughout the water column at the Bermuda Atlantic Time-series Study (BATS site in the summer (September and winter (March of three years. Viral phoH sequences reveal differences in the viral communities throughout a depth profile and between seasons in the same year. Variation was also detected between the same seasons in subsequent years, though these differences were not as great as the summer/winter distinctions. Over 3,600 phoH operational taxonomic units (OTUs; 97% sequence identity were identified. Despite high richness, most phoH sequences belong to a few large, common OTUs whereas the majority of the OTUs are small and rare. While many OTUs make sporadic appearances at just a few times or depths, a small number of OTUs dominate the community throughout the seasons, depths, and years.

  2. Promiscuous and specific phospholipid binding by domains in ZAC, a membrane-associated Arabidopsis protein with an ARF GAP zinc finger and a C2 domain

    DEFF Research Database (Denmark)

    Jensen, R B; Lykke-Andersen, K; Frandsen, G I

    2000-01-01

    domain are separated by a region without homology to other known proteins. Zac promoter/beta-glucuronidase reporter assays revealed highest expression levels in flowering tissue, rosettes and roots. ZAC protein was immuno-detected mainly in association with membranes and fractionated with Golgi...... and plasma membrane marker proteins. ZAC membrane association was confirmed in assays by a fusion between ZAC and the green fluorescence protein and prompted an analysis of the in vitro phospholipid-binding ability of ZAC. Phospholipid dot-blot and liposome-binding assays indicated that fusion proteins...... zinc finger motif, but proteins containing only the zinc finger domain (residues 1-105) did not bind PI-3-P. Recombinant ZAC possessed GTPase-activating activity on Arabidopsis ARF proteins. These data identify a novel PI-3-P-binding protein region and thereby provide evidence...

  3. Peptidoglycan-associated outer membrane protein Mep45 of rumen anaerobe Selenomonas ruminantium forms a non-specific diffusion pore via its C-terminal transmembrane domain.

    Science.gov (United States)

    Kojima, Seiji; Hayashi, Kanako; Tochigi, Saeko; Kusano, Tomonobu; Kaneko, Jun; Kamio, Yoshiyuki

    2016-10-01

    The major outer membrane protein Mep45 of Selenomonas ruminantium, an anaerobic Gram-negative bacterium, comprises two distinct domains: the N-terminal S-layer homologous (SLH) domain that protrudes into the periplasm and binds to peptidoglycan, and the remaining C-terminal transmembrane domain, whose function has been unknown. Here, we solubilized and purified Mep45 and characterized its function using proteoliposomes reconstituted with Mep45. We found that Mep45 forms a nonspecific diffusion channel via its C-terminal region. The channel was permeable to solutes smaller than a molecular weight of roughly 600, and the estimated pore radius was 0.58 nm. Truncation of the SLH domain did not affect the channel property. On the basis of the fact that Mep45 is the most abundant outer membrane protein in S. ruminantium, we conclude that Mep45 serves as a main pathway through which small solutes diffuse across the outer membrane of this bacterium.

  4. A Novel ¹¹¹In-Labeled Anti-Prostate-Specific Membrane Antigen Nanobody for Targeted SPECT/CT Imaging of Prostate Cancer.

    Science.gov (United States)

    Chatalic, Kristell L S; Veldhoven-Zweistra, Joke; Bolkestein, Michiel; Hoeben, Sander; Koning, Gerben A; Boerman, Otto C; de Jong, Marion; van Weerden, Wytske M

    2015-07-01

    Prostate-specific membrane antigen (PSMA) is overexpressed in prostate cancer (PCa) and a promising target for molecular imaging and therapy. Nanobodies (single-domain antibodies, VHH) are the smallest antibody-based fragments possessing ideal molecular imaging properties, such as high target specificity and rapid background clearance. We developed a novel anti-PSMA Nanobody (JVZ-007) for targeted imaging and therapy of PCa. Here, we report on the application of the (111)In-radiolabeled Nanobody for SPECT/CT imaging of PCa. A Nanobody library was generated by immunization of a llama with 4 human PCa cell lines. Anti-PSMA Nanobodies were captured by biopanning on PSMA-overexpressing cells. JVZ-007 was selected for evaluation as an imaging probe. JVZ-007 was initially produced with a c-myc-hexahistidine (his) tag allowing purification and detection. The c-myc-his tag was subsequently replaced by a single cysteine at the C terminus, allowing site-specific conjugation of chelates for radiolabeling. JVZ-007-c-myc-his was conjugated to 2-(4-isothiocyanatobenzyl)-diethylenetriaminepentaacetic acid (p-SCN-DTPA) via the lysines, whereas JVZ-007-cys was conjugated to maleimide-DTPA via the C-terminal cysteine. PSMA targeting was analyzed in vitro by cell-binding experiments using flow cytometry, autoradiography, and internalization assays with various PCa cell lines and patient-derived xenografts (PDXs). The targeting properties of radiolabeled Nanobodies were evaluated in vivo in biodistribution and SPECT/CT imaging experiments, using nude mice bearing PSMA-positive PC-310 and PSMA-negative PC-3 tumors. JVZ-007 was successfully conjugated to DTPA for radiolabeling with (111)In at room temperature. (111)In-JVZ007-c-myc-his and (111)In-JVZ007-cys internalized in LNCaP cells and bound to PSMA-expressing PDXs and, importantly, not to PSMA-negative PDXs and human kidneys. Good tumor targeting and fast blood clearance were observed for (111)In-JVZ-007-c-myc-his and (111)In

  5. Defining depth of anesthesia.

    Science.gov (United States)

    Shafer, S L; Stanski, D R

    2008-01-01

    In this chapter, drawn largely from the synthesis of material that we first presented in the sixth edition of Miller's Anesthesia, Chap 31 (Stanski and Shafer 2005; used by permission of the publisher), we have defined anesthetic depth as the probability of non-response to stimulation, calibrated against the strength of the stimulus, the difficulty of suppressing the response, and the drug-induced probability of non-responsiveness at defined effect site concentrations. This definition requires measurement of multiple different stimuli and responses at well-defined drug concentrations. There is no one stimulus and response measurement that will capture depth of anesthesia in a clinically or scientifically meaningful manner. The "clinical art" of anesthesia requires calibration of these observations of stimuli and responses (verbal responses, movement, tachycardia) against the dose and concentration of anesthetic drugs used to reduce the probability of response, constantly adjusting the administered dose to achieve the desired anesthetic depth. In our definition of "depth of anesthesia" we define the need for two components to create the anesthetic state: hypnosis created with drugs such as propofol or the inhalational anesthetics and analgesia created with the opioids or nitrous oxide. We demonstrate the scientific evidence that profound degrees of hypnosis in the absence of analgesia will not prevent the hemodynamic responses to profoundly noxious stimuli. Also, profound degrees of analgesia do not guarantee unconsciousness. However, the combination of hypnosis and analgesia suppresses hemodynamic response to noxious stimuli and guarantees unconsciousness.

  6. Lu-177-PSMA-617 Prostate-Specific Membrane Antigen Inhibitor Therapy in Patients with Castration-Resistant Prostate Cancer: Stability, Bio-distribution and Dosimetry

    Directory of Open Access Journals (Sweden)

    Levent Kabasakal

    2017-06-01

    Full Text Available Objective: The aim of the study was to estimate the radiation-absorbed doses and to study the in vivo and in vitro stability as well as pharmacokinetic characteristics of lutetium-177 (Lu-177 prostate-specific membrane antigen (PSMA-617. Methods: For this purpose, 7 patients who underwent Lu-177-PSMA therapy were included into the study. The injected Lu-177-PSMA-617 activity ranged from 3.6 to 7.4 GBq with a mean of 5.2±1.8 GBq. The stability of radiotracer in saline was calculated up to 48 h. The stability was also calculated in blood and urine samples. Post-therapeutic dosimetry was performed based on whole body and single photon emission computed tomography/computed tomography (SPECT/CT scans on dual-headed SPECT/CT system. Results: The radiochemical yield of Lu-177-PSMA-617 was >99%. It remained stable in saline up to 48 h. Analyses of the blood and urine samples showed a single radioactivity peak even at 24 hours after injection. Half-life of the distribution and elimination phases were calculated to be 0.16±0.09 and 10.8±2.5 hours, respectively. The mean excretion rate was 56.5±8.8% ranging from 41.5% to 65.4% at 24 h. Highest radiation estimated doses were calculated for parotid glands and kidneys (1.90±1.19 and 0.82±0.25 Gy/GBq respectively. Radiation dose given to the bone marrow was significantly lower than those of kidney and parotid glands (p<0.05 (0.030±0.008 Gy/GBq. Conclusion: Lu-177-PSMA-617 is a highly stable compound both in vitro and in vivo. Lu-177-PSMA-617 therapy seems to be a safe method for the treatment of castration-resistant prostate cancer patients. The fractionation regime that enables the longest duration of tumor control and/or survival will have to be developed in further studies.

  7. Construction of a recombinant adenovirus co-expressing truncated human prostate-specific membrane antigen and mouse 4-1BBL genes and its effect on dendritic cells

    Directory of Open Access Journals (Sweden)

    Xiaodong Weng

    2011-03-01

    Full Text Available Our aim was to construct a recombinant adenovirus co-expressing truncated human prostate-specific membrane antigen (tPSMA and mouse 4-1BBL genes and to determine its effect on dendritic cells (DCs generated from bone marrow suspensions harvested from C57BL/6 mice for which the effect of 4-1BBL on DCs is not clear, especially during DCs processing tumor-associated antigen. Replication deficient adenovirus AdMaxTM Expression System was used to construct recombinant adenovirus Ad-tPSMA-internal ribosome entry site-mouse 4-1BBL (Ad-tPSMA-IRES-m4-1BBL and Ad-enhanced green fluorescent protein. Day 7 proliferating DC aggregates generated from C57BL/6 mice were collected as immature DCs and further mature DCs were obtained by lipopolysaccharide activated immature DCs. After DCs were exposed to the recombinant adenovirus with 250 multiplicity of infection, the expression of tPSMA and m4-1BBL proteins were detected by Western blot, and the apoptosis and phenotype of DCs were analyzed by flow cytometry. Cytokines (IL-6 and IL-12 in the supernatant were detected by enzyme-linked immunosorbent assay (ELISA. Proliferation of T cells was detected by allogeneic mixed lymphocyte reactions. The tPSMA and m4-1BBL proteins were expressed correctly. The apoptosis rate of DCs transfected with Ad-tPSMA-IRES-m4-1BBL was 14.6%, lower than that of control DCs. The expression of co-stimulatory molecules [CD80 (81.6 ± 5.4% and CD86 (80.13 ± 2.81%] up-regulated in Ad-tPSMA-IRES-m4-1BBL-pulsed DCs, and the level of IL-6 (3960.2 ± 50.54 pg/mL and IL-12 (249.57 ± 12.51 pg/mL production in Ad-tPSMA-IRES-m4-1BBL-transduced DCs were significantly higher (P < 0.05 than those in control DCs. Ad-tPSMA-IRES-m4-1BBL induced higher T-cell proliferation (OD450 = 0.614 ± 0.018, indicating that this recombinant adenovirus can effectively enhance the activity of DCs.

  8. Membrane fusion and exocytosis.

    Science.gov (United States)

    Jahn, R; Südhof, T C

    1999-01-01

    Membrane fusion involves the merger of two phospholipid bilayers in an aqueous environment. In artificial lipid bilayers, fusion proceeds by means of defined transition states, including hourglass-shaped intermediates in which the proximal leaflets of the fusing membranes are merged whereas the distal leaflets are separate (fusion stalk), followed by the reversible opening of small aqueous fusion pores. Fusion of biological membranes requires the action of specific fusion proteins. Best understood are the viral fusion proteins that are responsible for merging the viral with the host cell membrane during infection. These proteins undergo spontaneous and dramatic conformational changes upon activation. In the case of the paradigmatic fusion proteins of the influenza virus and of the human immunodeficiency virus, an amphiphilic fusion peptide is inserted into the target membrane. The protein then reorients itself, thus forcing the fusing membranes together and inducing lipid mixing. Fusion of intracellular membranes in eukaryotic cells involves several protein families including SNAREs, Rab proteins, and Sec1/Munc-18 related proteins (SM-proteins). SNAREs form a novel superfamily of small and mostly membrane-anchored proteins that share a common motif of about 60 amino acids (SNARE motif). SNAREs reversibly assemble into tightly packed helical bundles, the core complexes. Assembly is thought to pull the fusing membranes closely together, thus inducing fusion. SM-proteins comprise a family of soluble proteins that bind to certain types of SNAREs and prevent the formation of core complexes. Rab proteins are GTPases that undergo highly regulated GTP-GDP cycles. In their GTP form, they interact with specific proteins, the effector proteins. Recent evidence suggests that Rab proteins function in the initial membrane contact connecting the fusing membranes but are not involved in the fusion reaction itself.

  9. Purification and characterization of two DyP isozymes from Thanatephorus cucumeris Dec 1 specifically expressed in an air-membrane surface bioreactor.

    Science.gov (United States)

    Shimokawa, Takuya; Shoda, Makoto; Sugano, Yasushi

    2009-02-01

    DyP isozymes (DyP2 and DyP3) from the culture fluid of the fungus Thanatephorus cucumeris Dec 1 by air-membrane surface bioreactor were purified and characterized. The characteristics of DyP2 were almost the same as those of a recombinant DyP reported previously, but different from DyP3.

  10. mRNA decay is regulated via the spatial sequestration of the conserved 5 '-3 ' exoribonuclease Xrn1 at a specific microdomain of the yeast plasma membrane

    Czech Academy of Sciences Publication Activity Database

    Vaškovičová, Katarína; Awadová, Thuraya; Veselá, Petra; Balážová, M.; Opekarová, Miroslava; Malínský, Jan

    2017-01-01

    Roč. 96, č. 6 (2017), s. 591-599 ISSN 0171-9335 R&D Projects: GA ČR(CZ) GA15-10641S Institutional support: RVO:68378041 Keywords : plasma membrane compartmentalization * eisosome * Pil1 Subject RIV: EA - Cell Biology OBOR OECD: Cell biology Impact factor: 3.712, year: 2016

  11. Defence in depth perspectives

    International Nuclear Information System (INIS)

    Veneau, Tania; Ferrier, Agnes; Barbaud, Jean

    2017-01-01

    The Defence in Depth (DiD) concept was introduced to the field of nuclear safety in the sixties and early seventies. Even though it was not well developed at the beginning, the principles rapidly became close to those currently used. The concept was then composed of 3 levels, and was already associated with operating conditions. These principles have progressed over time and now there are five levels, including progressively situations issued from design extension conditions, to cope with severe accidents and dealing with accident management off-site. Indeed, human and organizational features are considered as a part of the safety provisions at all levels in an integrated approach that is not just related to reactor design. That's the current vision from IAEA, addressed first in INSAG 3 then in INSAG 10, and in the IAEA standards requirements currently addressed by SSR-2/1 superseding NS-R-1). These five levels of DiD are also referred to in other texts including WENRA documents in Europe, but also in the national requirements from different countries. Thus, the application of DiD principle has become a recognized international practice. The 2011 Fukushima Daiichi accidents, even if they raised many questions on nuclear safety issues, confirmed the merits of the DiD concept. Indeed, lessons learned from the accidents have reinforced the use of the DiD concept to ensure adequate safety. The discussions focused more on the implementation of the concept (how it has been or can be used in practice) than the concept itself, and in particular on the following subjects: the notion of level robustness, generally addressed separately from the levels definition, but playing an important role for the efficiency of the concept; the notion of levels independence and the need for strengthening them; the role of diversity to achieve levels independence. However, a prescription of additional diversity and independence across all safety levels could result in inappropriately

  12. Molecular Interactions at Membranes

    DEFF Research Database (Denmark)

    Jagalski, Vivien

    . Today, we know more than ever before about the properties of biological membranes. Advanced biophysical techniques and sophisticated membrane models allow us to answer specific questions about the structure of the components within membranes and their interactions. However, many detailed structural...... the surface-immobilization of LeuT by exchanging the detergent with natural phosphatidylcholine (PC) lipids. Various surface sensitive techniques, including neutron reflectometry (NR), are employed and finally enabled us to confirm the gross structure of LeuT in a lipid environment as predicted by molecular...... dynamic simulations. In a second study, the co-localization of three toxic plant-derived diterpene resin acids (RAs) within DPPC membranes was investigated. These compounds are reported to disrupt the membrane and increase its fluidity. The RAs used in this study vary in their toxicity while...

  13. Membrane Biophysics

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2013-01-01

    Physics, mathematics and chemistry all play a vital role in understanding the true nature and functioning of biological membranes, key elements of living processes. Besides simple spectroscopic observations and electrical measurements of membranes we address in this book the phenomena of coexistence and independent existence of different membrane components using various theoretical approaches. This treatment will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of processes inside membranes, and will thus eventually open new doors for high-level pharmaceutical approaches towards fighting membrane- and cell-related diseases.

  14. Site-specific incorporation of 5-fluorotryptophan as a probe of the structure and function of the membrane-bound D-lactate dehydrogenase of Escherichia coli: A 19F nuclear magnetic resonance study

    International Nuclear Information System (INIS)

    Peersen, O.B.; Pratt, E.A.; Truong, H.T. N.; Ho, C.; Rule, G.S.

    1990-01-01

    The structure and function of the membrane-bound D-lactate dehydrogenase of Escherichia coli have been investigated by fluorine-19 nuclear magnetic resonance spectroscopy of 5-fluorotryptophan-labeled enzyme in conjunction with oligonucleotide-directed, site-specific mutagenesis. 5-Fluorotryptophan has been substituted for nine phenylalanine, tyrosine, and leucine residues in the enzyme molecule without loss of activity. The 19 F signals from these additional tryptophan residues have been used as markers for sensitivity to substrate, exposure to aqueous solvent, and proximity to a lipid-bound spin-label. The nuclear magnetic resonance data show that two mutational sites, at amino acid residues 340 and 361, are near the lipid environment used to stabilize the enzyme. There are a number of amino acid residues on the carboxyl side of this region that are strongly sensitive to the aqueous solvent. The environment of the wide-type tryptophan residue at position 469 changes as a result of two of the substitution mutations, suggesting some amino acid residue-residue interactions. Secondary structure prediction methods indicate a possible binding site for the flavin adenine dinucleotide cofactor in the carboxyl end of the enzyme molecule. These results suggest that the membrane-bound D-lactate dehydrogenase may have the two-domain structure of many cytoplasmic dehydrogenases but with the addition of a membrane-binding domain between the catalytic and cofactor-binding domains. This type of three-domain structure may be of general significance for understanding the structure of membrane-bound proteins which do not traverse the lipid bilayer of membranes

  15. The GRP1 PH domain, like the AKT1 PH domain, possesses a sentry glutamate residue essential for specific targeting to plasma membrane PI(3,4,5)P(3).

    Science.gov (United States)

    Pilling, Carissa; Landgraf, Kyle E; Falke, Joseph J

    2011-11-15

    During the appearance of the signaling lipid PI(3,4,5)P(3), an important subset of pleckstrin homology (PH) domains target signaling proteins to the plasma membrane. To ensure proper pathway regulation, such PI(3,4,5)P(3)-specific PH domains must exclude the more prevalant, constitutive plasma membrane lipid PI(4,5)P(2) and bind the rare PI(3,4,5)P(3) target lipid with sufficiently high affinity. Our previous study of the E17K mutant of the protein kinase B (AKT1) PH domain, together with evidence from Carpten et al. [Carpten, J. D., et al. (2007) Nature 448, 439-444], revealed that the native AKT1 E17 residue serves as a sentry glutamate that excludes PI(4,5)P(2), thereby playing an essential role in specific PI(3,4,5)P(3) targeting [Landgraf, K. E., et al. (2008) Biochemistry 47, 12260-12269]. The sentry glutamate hypothesis proposes that an analogous sentry glutamate residue is a widespread feature of PI(3,4,5)P(3)-specific PH domains, and that charge reversal mutation at the sentry glutamate position will yield both increased PI(4,5)P(2) affinity and constitutive plasma membrane targeting. To test this hypothesis, we investigated the E345 residue, a putative sentry glutamate, of the general receptor for phosphoinositides 1 (GRP1) PH domain. The results show that incorporation of the E345K charge reversal mutation into the GRP1 PH domain enhances PI(4,5)P(2) affinity 8-fold and yields constitutive plasma membrane targeting in cells, reminiscent of the effects of the E17K mutation in the AKT1 PH domain. Hydrolysis of plasma membrane PI(4,5)P(2) releases the E345K GRP1 PH domain into the cytoplasm, and the efficiency of this release increases when Arf6 binding is disrupted. Overall, the findings provide strong support for the sentry glutamate hypothesis and suggest that the GRP1 E345K mutation will be linked to changes in cell physiology and human pathologies, as demonstrated for AKT1 E17K [Carpten, J. D., et al. (2007) Nature 448, 439-444; Lindhurst, M. J., et al

  16. Targeted Expression of Stromelysin-1 in Mammary Gland Provides Evidence for a Role of Proteinases in Branching Morphogenesis and the Requirement for an Intact Basement Membrane for Tissue-specific Gene Expression

    Energy Technology Data Exchange (ETDEWEB)

    Sympson, Carolyn J; Talhouk, Rabih S; Alexander, Caroline M; Chin, Jennie R; Cliff, Shirley M; Bissell, Mina J; Werb, Zena

    1994-05-01

    The extracellular matrix (ECM) is an important regulator of the differentiated phenotype of mammary epithelial cells in culture. Despite the fact that ECM-degrading enzymes have been implicated in morphogenesis and tissue remodeling, there is little evidence for a direct role for such regulation in vivo. We generated transgenic mice that express autoactivated isoforms of the matrix metalloproteinase stromelysin-1, under the control of the whey acidic protein gene promoter, to examine the effect of inappropriate expression of this enzyme. Stromelysin-1 is implicated as the primary player in the loss of basement membrane and loss of function in the mammary gland during involution. The transgene was expressed at low levels in mammary glands of virgin female mice, leading to an unexpected phenotype: The primary ducts had supernumerary branches and showed precocious development of alveoli that expressed beta-casein at levels similar to that of an early- to mid-pregnant gland. Lactating glands showed high levels of transgene expression, with accumulation at the basement membrane, and a decrease in laminin and collagen IV, resulting in a loss of basement membrane integrity; this was accompanied by a dramatic alteration of alveolar morphology, with decreased size and shrunken lumina containing little beta-casein. During pregnancy, expression of endogenous whey acidic protein and beta-casein was reduced in transgenic glands, confirming the observed dependence of milk protein transcription of ECM in mammary epithelial cells in culture. These data provide direct evidence that stromelysin-1 activity can be morphogenic for mammary epithelial cells, inducing hyperproliferation and differentiation in virgin animals, and that its lytic activity can, indeed, disrupt membrane integrity and reduce mammary-specific function. We conclude that the balance of ECM-degrading enzymes with their inhibitors, and the associated regulation of ECM structure, is crucial for tissue-specific gene

  17. Tetrahymena gene encodes a protein that is homologous with the liver-specific F-antigen and associated with membranes of the Golgi apparatus and transport vesicles

    DEFF Research Database (Denmark)

    Hummel, R; Nørgaard, P; Andreasen, P H

    1992-01-01

    The F-antigen is a prominent liver protein which has been extensively used in studies on natural and induced immunological tolerance. However, its intracellular localization and biological function have remained elusive. It has generally been assumed that the F-antigen is confined phylogenetically...... of the Golgi apparatus and transport vesicles pointing to a role of TF-ag in membrane trafficking. Transcription of the TF-ag gene, as determined by run-on analyses, was only detectable in growing cells, and following transfer to starvation condition pre-existing TF-ag mRNA was rapidly degraded. The abundance...

  18. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane.

    Science.gov (United States)

    Ho, J; Smith, S; Roh, H K

    2014-01-01

    A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m(2)/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m(3) permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m(3)). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude.

  19. Shave-off depth profiling: Depth profiling with an absolute depth scale

    International Nuclear Information System (INIS)

    Nojima, M.; Maekawa, A.; Yamamoto, T.; Tomiyasu, B.; Sakamoto, T.; Owari, M.; Nihei, Y.

    2006-01-01

    Shave-off depth profiling provides profiling with an absolute depth scale. This method uses a focused ion beam (FIB) micro-machining process to provide the depth profile. We show that the shave-off depth profile of a particle reflected the spherical shape of the sample and signal intensities had no relationship to the depth. Through the introduction of FIB micro-sampling, the shave-off depth profiling of a dynamic random access memory (DRAM) tip was carried out. The shave-off profile agreed with a blue print from the manufacturing process. Finally, shave-off depth profiling is discussed with respect to resolutions and future directions

  20. A brain electrophysiological correlate of depth perception

    International Nuclear Information System (INIS)

    Akay, Ahmet; Celebi, Gurbuz

    2009-01-01

    To investigate brain electrical activity accompanying depth perception using random-dot stereograms. Additional experiments were conducted to ascertain the specificity of this potential to depth perception. In the present study, we performed 3 different and independent experiments on 34 subjects to establish the relationship between depth perception and its cortical electrophysiological correlate. Visual evoked potentials in response to visual stimulation by random-dot stereograms were recorded. To achieve this goal, a data acquisition and analysis system, different from common visual evoked potential recording systems, consisting of 2 personal computers, was used. One of the computers was used to generate the visual stimulus patterns and the other to record and digitally average the potentials evoked by the stimuli. This study was carried out at the Department of Biophysics of Ege University Medical School, Izmir, Turkey, from April to December, 2006. A negative potential component, which is thought to arise in association with depth perception, was recorded from the occipital region from 30 of the 34 subjects. Typically, it had a mean latency of 211.46 ms and 6.40 micron V amplitude. The negative potential is related to depth perception, as this component is present in the responses to stimulus, which carries disparity information but is absent when the stimulus is switched to no disparity information. Additional experiments also showed that the specificity of this component to depth perception becomes evident beyond doubt. (author)

  1. Institutional Strength in Depth

    International Nuclear Information System (INIS)

    Weightman, M.

    2016-01-01

    Much work has been undertaken in order to identify, learn and implement the lessons from the TEPCO Fukushima Daiichi nuclear accident. These have mainly targeted on engineering or operational lessons. Less attention has been paid to the institutional lessons, although there have been some measures to improve individual peer reviews, particularly by the World Association of Nuclear Operators, and the authoritative IAEA report published in 2015 brought forward several important lessons for regulators and advocated a system approach. The report noted that one of the contributing factors the accident was the tendency of stakeholders not to challenge. Additionally, it reported deficiencies in the regulatory authority and system. Earlier, the root cause of the accident was identified by a Japanese independent parliamentary report as being cultural and institutional. The sum total of the institutions, the safety system, was ineffective. While it is important to address the many technical and operational lessons these may not necessary address this more fundamental lesson, and may not serve to provide robust defences against human or institutional failings over a wide variety of possible events and combinations. The overall lesson is that we can have rigorous and comprehensive safety standards and other tools in place to deliver high levels of safety, but ultimately what is important is the ability of the nuclear safety system to ensure that the relevant institutions diligently and effectively apply those standards and tools — to be robust and resilient. This has led to the consideration of applying the principles of the strength in depth philosophy to a nuclear safety system as a way of providing a framework for developing, assessing, reviewing and improving the system. At an IAEA conference in October 2013, a model was presented for a robust national nuclear safety system based on strength in depth philosophy. The model highlighted three main layers: industry, the

  2. Membrane paradigm

    International Nuclear Information System (INIS)

    Price, R.H.; Thorne, K.S.

    1986-01-01

    The membrane paradigm is a modified frozen star approach to modeling black holes, with particles and fields assuming a complex, static, boundary-layer type structure (membrane) near the event horizon. The membrane has no effects on the present or future evolution of particles and fields above itself. The mathematical representation is a combination of a formalism containing terms for the shear and bulk viscosity, surface pressure, momentum, temperature, entropy, etc., of the horizon and the 3+1 formalism. The latter model considers a family of three-dimensional spacelike hypersurfaces in one-dimensional time. The membrane model considers a magnetic field threading the hole and undergoing torque from the hole rotation. The field is cleaned by the horizon and distributed over the horizon so that ohmic dissipation is minimized. The membrane paradigm is invalid inside the horizon, but is useful for theoretically probing the properties of slowly evolving black holes

  3. Membrane processes

    Science.gov (United States)

    Staszak, Katarzyna

    2017-11-01

    The membrane processes have played important role in the industrial separation process. These technologies can be found in all industrial areas such as food, beverages, metallurgy, pulp and paper, textile, pharmaceutical, automotive, biotechnology and chemical industry, as well as in water treatment for domestic and industrial application. Although these processes are known since twentieth century, there are still many studies that focus on the testing of new membranes' materials and determining of conditions for optimal selectivity, i. e. the optimum transmembrane pressure (TMP) or permeate flux to minimize fouling. Moreover the researchers proposed some calculation methods to predict the membrane processes properties. In this article, the laboratory scale experiments of membrane separation techniques, as well their validation by calculation methods are presented. Because membrane is the "heart" of the process, experimental and computational methods for its characterization are also described.

  4. Offshore Wind Technology Depth Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coastal bathymetric depth, measured in meters at depth values of: -30, -60, -900 Shallow Zone (0-30m): Technology has been demonstrated on a commercial scale at...

  5. Energy conservation employing membrane-based technology

    International Nuclear Information System (INIS)

    Narayanan, C.M.

    1993-01-01

    Membranes based processes, if properly adapted to industrial processes have good potential with regard to optimisation and economisation of energy consumption. The specific benefits of MBT (membrane based technology) as an energy conservation methodology are highlighted. (author). 6 refs

  6. Comparison and analysis of membrane fouling between flocculent sludge membrane bioreactor and granular sludge membrane bioreactor.

    Directory of Open Access Journals (Sweden)

    Wang Jing-Feng

    Full Text Available The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs, two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates.

  7. Primordial membranes

    DEFF Research Database (Denmark)

    Hanczyc, Martin M; Monnard, Pierre-Alain

    2017-01-01

    Cellular membranes, which are self-assembled bilayer structures mainly composed of lipids, proteins and conjugated polysaccharides, are the defining feature of cell physiology. It is likely that the complexity of contemporary cells was preceded by simpler chemical systems or protocells during...... the various evolutionary stages that led from inanimate to living matter. It is also likely that primitive membranes played a similar role in protocell 'physiology'. The composition of such ancestral membranes has been proposed as mixtures of single hydrocarbon chain amphiphiles, which are simpler versions...

  8. Penetration of the signal sequence of Escherichia coli PhoE protein into phospholipid model membranes leads to lipid-specific changes in signal peptide structure and alterations of lipid organization

    International Nuclear Information System (INIS)

    Batenburg, A.M.; Demel, R.A.; Verkleij, A.J.; de Kruijff, B.

    1988-01-01

    In order to obtain more insight in the initial steps of the process of protein translocation across membranes, biophysical investigations were undertaken on the lipid specificity and structural consequences of penetration of the PhoE signal peptide into lipid model membranes and on the conformation of the signal peptide adopted upon interaction with the lipids. When the monolayer technique and differential scanning calorimetry are used, a stronger penetration is observed for negatively charged lipids, significantly influenced by the physical state of the lipid but not by temperature or acyl chain unsaturation as such. Although the interaction is principally electrostatic, as indicated also by the strong penetration of N-terminal fragments into negatively charged lipid monolayers, the effect of ionic strength suggests an additional hydrophobic component. Most interestingly with regard to the mechanism of protein translocation, the molecular area of the peptide in the monolayer also shows lipid specificity: the area in the presence of PC is consistent with a looped helical orientation, whereas in the presence of cardiolipin a time-dependent conformational change is observed, most likely leading from a looped to a stretched orientation with the N-terminus directed toward the water. This is in line also with the determined peptide-lipid stoichiometry. Preliminary 31 P NMR and electron microscopy data on the interaction with lipid bilayer systems indicate loss of bilayer structure

  9. Role of the membrane skeleton in preventing the shedding of procoagulant-rich microvesicles from the platelet plasma membrane

    OpenAIRE

    1990-01-01

    The platelet plasma membrane is lined by a membrane skeleton that appears to contain short actin filaments cross-linked by actin-binding protein. Actin-binding protein is in turn associated with specific plasma membrane glycoproteins. The aim of this study was to determine whether the membrane skeleton regulates properties of the plasma membrane. Platelets were incubated with agents that disrupted the association of the membrane skeleton with membrane glycoproteins. The consequences of this c...

  10. Development of an air bleeding technique and specific duration to improve the CO tolerance of proton-exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Chung, Chen-Chung; Chen, Chiun-Hsun; Weng, De-Zheng

    2009-01-01

    This study investigated transient CO poisoning of a proton-exchange membrane fuel cell under either a fixed cell voltage or fixed current density. During CO poisoning tests, the cell performance decreases over time. Experiments were performed to identify which method yields better performance in CO poisoning tests. The results revealed that a change in cell voltage did not affect the stable polarization behavior after CO poisoning of the cell. On the other hand, a higher fixed current density yielded better tolerance of 52.7 ppm CO. The air bleeding technique was then applied using different timings for air introduction during CO poisoning tests. Air bleeding significantly improved the CO tolerance of the cell and recovered the performance after poisoning, regardless of the timing of air introduction. The effects of different anode catalyst materials on cell performance were also investigated during poisoning tests. Without air bleeding, a Pt-Ru alloy catalyst exhibited better CO tolerance than a pure Pt catalyst. However, the air bleeding technique can effectively increase the CO tolerance of cells regardless of the type of catalyst used.

  11. The role of hydrophobic interactions in positioning of peripheral proteins in membranes

    Directory of Open Access Journals (Sweden)

    Lomize Mikhail A

    2007-06-01

    Full Text Available Abstract Background Three-dimensional (3D structures of numerous peripheral membrane proteins have been determined. Biological activity, stability, and conformations of these proteins depend on their spatial positions with respect to the lipid bilayer. However, these positions are usually undetermined. Results We report the first large-scale computational study of monotopic/peripheral proteins with known 3D structures. The optimal translational and rotational positions of 476 proteins are determined by minimizing energy of protein transfer from water to the lipid bilayer, which is approximated by a hydrocarbon slab with a decadiene-like polarity and interfacial regions characterized by water-permeation profiles. Predicted membrane-binding sites, protein tilt angles and membrane penetration depths are consistent with spin-labeling, chemical modification, fluorescence, NMR, mutagenesis, and other experimental studies of 53 peripheral proteins and peptides. Experimental membrane binding affinities of peripheral proteins were reproduced in cases that did not involve a helix-coil transition, specific binding of lipids, or a predominantly electrostatic association. Coordinates of all examined peripheral proteins and peptides with the calculated hydrophobic membrane boundaries, subcellular localization, topology, structural classification, and experimental references are available through the Orientations of Proteins in Membranes (OPM database. Conclusion Positions of diverse peripheral proteins and peptides in the lipid bilayer can be accurately predicted using their 3D structures that represent a proper membrane-bound conformation and oligomeric state, and have membrane binding elements present. The success of the implicit solvation model suggests that hydrophobic interactions are usually sufficient to determine the spatial position of a protein in the membrane, even when electrostatic interactions or specific binding of lipids are substantial. Our

  12. Molecular dynamics simulations of membrane deformation induced by amphiphilic helices of Epsin, Sar1p, and Arf1

    Science.gov (United States)

    Li, Zhen-Lu

    2018-03-01

    The N-terminal amphiphilic helices of proteins Epsin, Sar1p, and Arf1 play a critical role in initiating membrane deformation. The interactions of these amphiphilic helices with the lipid membranes are investigated in this study by combining the all-atom and coarse-grained simulations. In the all-atom simulations, the amphiphilic helices of Epsin and Sar1p are found to have a shallower insertion depth into the membrane than the amphiphilic helix of Arf1, but remarkably, the amphiphilic helices of Epsin and Sar1p induce higher asymmetry in the lipid packing between the two monolayers of the membrane. The insertion depth of amphiphilic helix into the membrane is determined not only by the overall hydrophobicity but also by the specific distributions of polar and non-polar residues along the helix. To directly compare their ability to deform the membrane, the coarse-grained simulations are performed to investigate the membrane deformation under the insertion of multiple helices. Project supported by the National Natural Science Foundation of China (Grant Nos. 91427302 and 11474155).

  13. Membranous nephropathy

    Science.gov (United States)

    ... skin-lightening creams Systemic lupus erythematosus , rheumatoid arthritis, Graves disease, and other autoimmune disorders The disorder occurs at ... diagnosis. The following tests can help determine the cause of membranous nephropathy: Antinuclear antibodies test Anti-double- ...

  14. Experimental approaches to membrane thermodynamics

    DEFF Research Database (Denmark)

    Westh, Peter

    2009-01-01

    Thermodynamics describes a system on the macroscopic scale, yet it is becoming an important tool for the elucidation of many specific molecular aspects of membrane properties. In this note we discuss this application of thermodynamics, and give a number of examples on how thermodynamic measurements...... have contributed to the understanding of specific membrane phenomena. We mainly focus on non-specific interactions of bilayers and small molecules (water and solutes) in the surrounding solvent, and the changes in membrane properties they bring about. Differences between thermodynamic...

  15. Flux Enhancement in Membrane Distillation Using Nanofiber Membranes

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2016-01-01

    Full Text Available Membrane distillation (MD is an emerging separation technology, whose largest application potential lies in the desalination of highly concentrated solutions, which are out of the scope of reverse osmosis. Despite many attractive features, this technology is still awaiting large industrial application. The main reason is the lack of commercially available membranes with fluxes comparable to reverse osmosis. MD is a thermal separation process driven by a partial vapour pressure difference. Flux, distillate purity, and thermal efficiency are always in conflict, all three being strictly connected with pore size, membrane hydrophobicity, and thickness. The world has not seen the ideal membrane yet, but nanofibers may offer a solution to these contradictory requirements. Membranes of electrospun PVDF were tested under various conditions on a direct contact (DCMD unit, in order to determine the optimum conditions for maximum flux. In addition, their performance was compared to commonly available PTFE, PE, and PES membranes. It was confirmed that thinner membranes have higher fluxes and a lower distillate purity and also higher energy losses via conduction across the membrane. As both mass and heat transfer are connected, it is best to develop new membranes with a target application in mind, for the specific membrane module and operational conditions.

  16. The M-current contributes to high threshold membrane potential oscillations in a cell type-specific way in the pedunculopontine nucleus of mice

    Directory of Open Access Journals (Sweden)

    Csilla eBordas

    2015-04-01

    Full Text Available The pedunculopontine nucleus is known as a cholinergic nucleus of the reticular activating system, participating in regulation of sleep and wakefulness. Besides cholinergic neurons, it consists of GABAergic and glutamatergic neurons as well. According to classical and recent studies, more subgroups of neurons were defined. Groups based on the neurotransmitter released by a neuron are not homogenous, but can be further subdivided.The PPN neurons do not only provide cholinergic and non-cholinergic inputs to several subcortical brain areas but they are also targets of cholinergic and other different neuromodulatory actions. Although cholinergic neuromodulation has been already investigated in the nucleus, one of its characteristic targets, the M-type potassium current has not been described yet.Using slice electrophysiology, we provide evidence in the present work that cholinergic neurons possess M-current, whereas GABAergic neurons lack it. The M-current contributes to certain functional differences of cholinergic and GABAergic neurons, as spike frequency adaptation, action potential firing frequency or the amplitude difference of medium afterhyperpolarizations. Furthermore, we showed that high threshold membrane potential oscillation with high power, around 20 Hz frequency is a functional property of almost all cholinergic cells, whereas GABAergic neurons have only low amplitude oscillations. Blockade of the M-current abolished the oscillatory activity at 20 Hz, and largely diminished it at other frequencies.Taken together, the M-current seems to be characteristic for PPN cholinergic neurons. It provides a possibility for modulating gamma band activity of these cells, thus contributing to neuromodulatory regulation of the reticular activating system.

  17. Site-specific epsilon-NH2 monoacylation of pancreatic phospholipase A2. 2. Transformation of soluble phospholipase A2 into a highly penetrating "membrane-bound" form.

    Science.gov (United States)

    Van der Wiele, F C; Atsma, W; Roelofsen, B; van Linde, M; Van Binsbergen, J; Radvanyi, F; Raykova, D; Slotboom, A J; De Haas, G H

    1988-03-08

    Long-chain lecithins present in bilayer structures like vesicles or membranes are only very poor substrates for pancreatic phospholipases A2. This is probably due to the fact that pancreatic phospholipases A2 cannot penetrate into the densely packed bilayer structures. To improve the weak penetrating properties of pancreatic phospholipases A2, we prepared and characterized a number of pancreatic phospholipase A2 mutants that have various long acyl chains linked covalently to Lys116 in porcine and to Lys10 in bovine phospholipase A2 [Van der Wiele, F.C., Atsma, W., Dijkman, R., Schreurs, A.M.M., Slotboom, A.J., & De Haas, G.H. (1988) Biochemistry (preceding paper in this issue)]. When monomolecular surface layers of L- and D-didecanoyllecithin were used, it was found that the introduction of caprinic, lauric, palmitic, and oleic acid at Lys116 in the porcine enzyme increases its penetrating power from 13 to about 17, 20, 32, and 22 dyn/cm, respectively, before long lag periods were obtained. Incorporation of a palmitoyl moiety at Lys10 in the bovine enzyme shifted the penetrating power from 11 to about 25 dyn/cm. Only the best penetrating mutant, viz., porcine phospholipase A2 having a palmitoyl moiety at Lys116, was able to cause complete leakage of 6-carboxyfluorescein entrapped in small unilamellar vesicles of egg lecithin under nonhydrolytic conditions. Similarly, only this latter palmitoylphospholipase A2 completely hydrolyzed all lecithin in the outer monolayer of the human erythrocyte at a rate much faster than Naja naja phospholipase A2, the most powerful penetrating snake venom enzyme presently known.

  18. Brain-specific interaction of a 91-kDa membrane-bound protein with the cytoplasmic tail of the 300-kDa mannose 6-phosphate receptor

    DEFF Research Database (Denmark)

    Rosorius, O; Issinger, O G; Braulke, T

    1996-01-01

    The cytoplasmic tail of the 300 kDa mannose 6-phosphate receptor (MPR 300-CT) is thought to play an important role in sorting and targeting of lysosomal enzymes and the insulin-like growth factor II along the biosynthetic and endocytic pathway. In this study a brain specific 91 kDa protein and a ...... in neuronal cells....

  19. Identification of conserved prolyl residue important for transport activity and the substrate specificity range of yeast plasma membrane Na(+)/H(+) antiporters

    Czech Academy of Sciences Publication Activity Database

    Zimmermannová, Olga; Zavřel, Martin; Sychrová, Hana

    2005-01-01

    Roč. 280, č. 34 (2005), s. 30638-30647 ISSN 0021-9258 R&D Projects: GA ČR(CZ) GP204/02/D092 Institutional research plan: CEZ:AV0Z5011922 Keywords : yeast * Na+/H+ antiporter * substrate specificity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.854, year: 2005

  20. Mathematical modelling of membrane separation

    DEFF Research Database (Denmark)

    Vinther, Frank

    This thesis concerns mathematical modelling of membrane separation. The thesis consists of introductory theory on membrane separation, equations of motion, and properties of dextran, which will be the solute species throughout the thesis. Furthermore, the thesis consist of three separate mathemat......This thesis concerns mathematical modelling of membrane separation. The thesis consists of introductory theory on membrane separation, equations of motion, and properties of dextran, which will be the solute species throughout the thesis. Furthermore, the thesis consist of three separate...... mathematical models, each with a different approach to membrane separation. The first model is a statistical model investigating the interplay between solute shape and the probability of entering the membrane. More specific the transition of solute particles from being spherical to becoming more elongated...

  1. Evaluation of Depth of Field for depth perception in DVR

    KAUST Repository

    Grosset, A.V.Pascal; Schott, Mathias; Bonneau, Georges-Pierre; Hansen, Charles D.

    2013-01-01

    In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

  2. Evaluation of Depth of Field for depth perception in DVR

    KAUST Repository

    Grosset, A.V.Pascal

    2013-02-01

    In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

  3. Membrane compartment of Can1 (MCC): specialized functional microdomain of the yeast plasma membrane

    OpenAIRE

    Doudová, Lenka

    2017-01-01

    Membrane compartment of Can1 (MCC): specialized functional microdomain of the yeast plasma membrane Yeast plasma membrane is divided into several different compartments. Membrane compartment of Can1 is specific for its protein and lipid composition, furthermore it creates furrow-like invaginations on the plasma membrane. These invaginations are made by multiprotein complexes called eisosomes, which are located in the cytosolic side of MCCs. It was established that this domain plays an importa...

  4. Positron depth profiling

    International Nuclear Information System (INIS)

    Coleman, P.

    2001-01-01

    Wide-ranging studies of defects below the surface of semiconductor structures have been performed at the University of Bath, in collaboration with the University of Surrey Centre for Ion Beam Applications and with members of research teams at a number of UK universities. Positron implantation has been used in conjunction with other spectroscopies such as RBS-channeling and SIMS, and electrical characterisation methods. Research has ranged from the development of a positron-based technique to monitor the in situ annealing of near-surface open-volume defects to the provision of information on defects to comprehensive diagnostic investigations of specific device structures. We have studied Si primarily but not exclusively; e.g., we have investigated ion-implanted SiC and SiO 2 /GaAs structures. Of particular interest are the applications of positron annihilation spectroscopy to ion-implanted semiconductors, where by linking ion dose to vacancy-type defect concentration one can obtain information on ion dose and uniformity with a sensitivity not achievable by standard techniques. A compact, user-friendly positron beam system is currently being developed at Bath, in collaboration with SCRIBA, with the intention of application in an industrial environment. (orig.)

  5. Importance of the seryl and threonyl residues of the fifth transmembrane domain to the substrate specificity of yeast plasma membrane Na+/H+ antiporters

    Czech Academy of Sciences Publication Activity Database

    Zimmermannová, Olga; Zavřel, Martin; Sychrová, Hana

    2006-01-01

    Roč. 23, č. 4 (2006), s. 349-361 ISSN 0968-7688 R&D Projects: GA MŠk(CZ) LC531; GA ČR(CZ) GP204/02/D092 Institutional research plan: CEZ:AV0Z50110509 Keywords : Na+/H+ antiporter * substrate specificity * hydroxyl groups Subject RIV: CE - Biochemistry Impact factor: 3.250, year: 2006

  6. Yeast plasma membrane Na/H antiporter - importance of OH groups in the 5th tms for activity and substrate specificity

    Czech Academy of Sciences Publication Activity Database

    Zimmermannová, Olga; Sychrová, Hana

    2007-01-01

    Roč. 274, Suppl.1 (2007), s. 127-127 ISSN 1742-464X. [FEBS Congress Molecular Machines /32./. 07.07.2007-12.07.2007, Vienna] R&D Projects: GA MŠk(CZ) LC531; GA AV ČR(CZ) IAA5011407 Institutional research plan: CEZ:AV0Z50110509 Keywords : cpo1 * Na/H antiporter * yeast * substrate specificity Subject RIV: EE - Microbiology, Virology

  7. Persistence of collagen type II-specific T-cell clones in the synovial membrane of a patient with rheumatoid arthritis

    International Nuclear Information System (INIS)

    Londei, M.; Savill, C.M.; Verhoef, A.; Brennan, F.; Leech, Z.A.; Feldmann, M.; Duance, V.; Maini, R.N.

    1989-01-01

    Rheumatoid arthritis is an autoimmune disease characterized by T-cell infiltration of the synovium of joints. Analysis of the phenotype and antigen specificity of the infiltrating cells may thus provide insight into the pathogenesis of rheumatoid arthritis. T cells were cloned with interleukin 2, a procedure that selects for in vivo-activated cells. All clones had the CD4 CDW29 phenotype. Their antigen specificity was tested by using a panel of candidate joint autoantigens. Four of 17 reacted against autologous blood mononuclear cells. Two clones proliferated in response to collagen type II. After 21 months, another set of clones was derived from synovial tissue of the same joint. One of eight clones tested showed a strong proliferative response against collagen type II. The uncloned synovial T cells of a third operation from another joint also responded to collagen type II. The persistence of collagen type II-specific T cells in active rheumatoid joints over a period of 3 years suggests that collagen type II could be one of the autoantigens involved in perpetuating the inflammatory process in rheumatoid arthritis

  8. Simultaneous targeting of prostate stem cell antigen and prostate-specific membrane antigen improves the killing of prostate cancer cells using a novel modular T cell-retargeting system.

    Science.gov (United States)

    Arndt, Claudia; Feldmann, Anja; Koristka, Stefanie; Cartellieri, Marc; Dimmel, Maria; Ehninger, Armin; Ehninger, Gerhard; Bachmann, Michael

    2014-09-01

    Recently, we described a novel modular platform technology in which T cell-recruitment and tumor-targeting domains of conventional bispecific antibodies are split to independent components, a universal effector module (EM) and replaceable monospecific/monovalent target modules (TMs) that form highly efficient T cell-retargeting complexes. Theoretically, our unique strategy should allow us to simultaneously retarget T cells to different tumor antigens by combining the EM with two or more different monovalent/monospecific TMs or even with bivalent/bispecific TMs, thereby overcoming limitations of a monospecific treatment such as the selection of target-negative tumor escape variants. In order to advance our recently introduced prostate stem cell antigen (PSCA)-specific modular system for a dual-targeting of prostate cancer cells, two additional TMs were constructed: a monovalent/monospecific TM directed against the prostate-specific membrane antigen (PSMA) and a bivalent/bispecific TM (bsTM) with specificity for PSMA and PSCA. The functionality of the novel dual-targeting strategies was analyzed by performing T cell activation and chromium release assays. Similar to the PSCA-specific modular system, the novel PSMA-specific modular system mediates an efficient target-dependent and -specific tumor cell lysis at low E:T ratios and picomolar Ab concentrations. Moreover, by combination of the EM with either the bispecific TM directed to PSMA and PSCA or both monospecifc TMs directed to either PSCA or PSMA, dual-specific targeting complexes were formed which allowed us to kill potential escape variants expressing only one or the other target antigen. Overall, the novel modular system represents a promising tool for multiple tumor targeting. © 2014 Wiley Periodicals, Inc.

  9. Protection by meningococcal outer membrane protein PorA-specific antibodies and a serogroup B capsular polysaccharide-specific antibody in complement-sufficient and C6-deficient infant rats

    NARCIS (Netherlands)

    Toropainen, Maija; Saarinen, Leena; Vidarsson, Gestur; Käyhty, Helena

    2006-01-01

    The relative contributions of antibody-induced complement-mediated bacterial lysis and antibody/complement-mediated phagocytosis to host immunity against meningococcal infections are currently unclear. Further, the in vivo effector functions of antibodies may vary depending on their specificity and

  10. Local Ca²+ entry via Orai1 regulates plasma membrane recruitment of TRPC1 and controls cytosolic Ca²+ signals required for specific cell functions.

    Directory of Open Access Journals (Sweden)

    Kwong Tai Cheng

    2011-03-01

    Full Text Available Store-operated Ca²+ entry (SOCE has been associated with two types of channels: CRAC channels that require Orai1 and STIM1 and SOC channels that involve TRPC1, Orai1, and STIM1. While TRPC1 significantly contributes to SOCE and SOC channel activity, abrogation of Orai1 function eliminates SOCE and activation of TRPC1. The critical role of Orai1 in activation of TRPC1-SOC channels following Ca²+ store depletion has not yet been established. Herein we report that TRPC1 and Orai1 are components of distinct channels. We show that TRPC1/Orai1/STIM1-dependent I(SOC, activated in response to Ca²+ store depletion, is composed of TRPC1/STIM1-mediated non-selective cation current and Orai1/STIM1-mediated I(CRAC; the latter is detected when TRPC1 function is suppressed by expression of shTRPC1 or a STIM1 mutant that lacks TRPC1 gating, STIM1(⁶⁸⁴EE⁶⁸⁵. In addition to gating TRPC1 and Orai1, STIM1 mediates the recruitment and association of the channels within ER/PM junctional domains, a critical step in TRPC1 activation. Importantly, we show that Ca²+ entry via Orai1 triggers plasma membrane insertion of TRPC1, which is prevented by blocking SOCE with 1 µM Gd³+, removal of extracellular Ca²+, knockdown of Orai1, or expression of dominant negative mutant Orai1 lacking a functional pore, Orai1-E106Q. In cells expressing another pore mutant of Orai1, Orai1-E106D, TRPC1 trafficking is supported in Ca²+-containing, but not Ca²+-free, medium. Consistent with this, I(CRAC is activated in cells pretreated with thapsigargin in Ca²+-free medium while I(SOC is activated in cells pretreated in Ca²+-containing medium. Significantly, TRPC1 function is required for sustained K(Ca activity and contributes to NFκB activation while Orai1 is sufficient for NFAT activation. Together, these findings reveal an as-yet unidentified function for Orai1 that explains the critical requirement of the channel in the activation of TRPC1 following Ca²+ store

  11. Axionic membranes

    International Nuclear Information System (INIS)

    Aurilia, A.; Spallucci, E.

    1992-01-01

    A metal ring removed from a soap-water solution encloses a film of soap which can be mathematically described as a minimal surface having the ring as its only boundary. This is known to everybody. In this letter we suggest a relativistic extension of the above fluidodynamic system where the soap film is replaced by a Kalb-Ramand gauge potential B μν (x) and the ring by a closed string. The interaction between the B μν field and the string current excites a new configuration of the system consisting of a relativistic membrane bounded by the string. We call such a classical solution of the equation of motion an axionic membrane. As a dynamical system, the axionic membrane admits a Hamilton-Jacobi formulation which is an extension of the HJ theory of electromagnetic strings. (orig.)

  12. Metamaterial membranes

    International Nuclear Information System (INIS)

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2017-01-01

    We introduce a new class of metamaterial device to achieve separation of compounds by using coordinate transformations and metamaterial theory. By rationally designing the spatial anisotropy for mass diffusion, we simultaneously concentrate different compounds in different spatial locations, leading to separation of mixtures across a metamaterial membrane. The separation of mixtures into their constituent compounds is critically important in biophysics, biomedical, and chemical applications. We present a practical case where a mixture of oxygen and nitrogen diffusing through a polymeric planar matrix is separated. This work opens doors to new paradigms in membrane separations via coordinate transformations and metamaterials by introducing novel properties and unconventional mass diffusion phenomena. (paper)

  13. Membrane docking geometry of GRP1 PH domain bound to a target lipid bilayer: an EPR site-directed spin-labeling and relaxation study.

    Directory of Open Access Journals (Sweden)

    Huai-Chun Chen

    Full Text Available The second messenger lipid PIP(3 (phosphatidylinositol-3,4,5-trisphosphate is generated by the lipid kinase PI3K (phosphoinositide-3-kinase in the inner leaflet of the plasma membrane, where it regulates a broad array of cell processes by recruiting multiple signaling proteins containing PIP(3-specific pleckstrin homology (PH domains to the membrane surface. Despite the broad importance of PIP(3-specific PH domains, the membrane docking geometry of a PH domain bound to its target PIP(3 lipid on a bilayer surface has not yet been experimentally determined. The present study employs EPR site-directed spin labeling and relaxation methods to elucidate the membrane docking geometry of GRP1 PH domain bound to bilayer-embedded PIP(3. The model target bilayer contains the neutral background lipid PC and both essential targeting lipids: (i PIP(3 target lipid that provides specificity and affinity, and (ii PS facilitator lipid that enhances the PIP(3 on-rate via an electrostatic search mechanism. The EPR approach measures membrane depth parameters for 18 function-retaining spin labels coupled to the PH domain, and for calibration spin labels coupled to phospholipids. The resulting depth parameters, together with the known high resolution structure of the co-complex between GRP1 PH domain and the PIP(3 headgroup, provide sufficient constraints to define an optimized, self-consistent membrane docking geometry. In this optimized geometry the PH domain engulfs the PIP(3 headgroup with minimal bilayer penetration, yielding the shallowest membrane position yet described for a lipid binding domain. This binding interaction displaces the PIP(3 headgroup from its lowest energy position and orientation in the bilayer, but the headgroup remains within its energetically accessible depth and angular ranges. Finally, the optimized docking geometry explains previous biophysical findings including mutations observed to disrupt membrane binding, and the rapid lateral

  14. Membrane interaction of retroviral Gag proteins

    Directory of Open Access Journals (Sweden)

    Robert Alfred Dick

    2014-04-01

    Full Text Available Assembly of an infectious retroviral particle relies on multimerization of the Gag polyprotein at the inner leaflet of the plasma membrane. The three domains of Gag common to all retroviruses-- MA, CA, and NC-- provide the signals for membrane binding, assembly, and viral RNA packaging, respectively. These signals do not function independently of one another. For example, Gag multimerization enhances membrane binding and is more efficient when NC is interacting with RNA. MA binding to the plasma membrane is governed by several principles, including electrostatics, recognition of specific lipid head groups, hydrophobic interactions, and membrane order. HIV-1 uses many of these principles while Rous sarcoma virus (RSV appears to use fewer. This review describes the principles that govern Gag interactions with membranes, focusing on RSV and HIV-1 Gag. The review also defines lipid and membrane behavior, and discusses the complexities in determining how lipid and membrane behavior impact Gag membrane binding.

  15. Optimization of amino acid type-specific 13C and 15N labeling for the backbone assignment of membrane proteins by solution- and solid-state NMR with the UPLABEL algorithm

    International Nuclear Information System (INIS)

    Hefke, Frederik; Bagaria, Anurag; Reckel, Sina; Ullrich, Sandra Johanna; Dötsch, Volker; Glaubitz, Clemens; Güntert, Peter

    2011-01-01

    We present a computational method for finding optimal labeling patterns for the backbone assignment of membrane proteins and other large proteins that cannot be assigned by conventional strategies. Following the approach of Kainosho and Tsuji (Biochemistry 21:6273–6279 (1982)), types of amino acids are labeled with 13 C or/and 15 N such that cross peaks between 13 CO(i – 1) and 15 NH(i) result only for pairs of sequentially adjacent amino acids of which the first is labeled with 13 C and the second with 15 N. In this way, unambiguous sequence-specific assignments can be obtained for unique pairs of amino acids that occur exactly once in the sequence of the protein. To be practical, it is crucial to limit the number of differently labeled protein samples that have to be prepared while obtaining an optimal extent of labeled unique amino acid pairs. Our computer algorithm UPLABEL for optimal unique pair labeling, implemented in the program CYANA and in a standalone program, and also available through a web portal, uses combinatorial optimization to find for a given amino acid sequence labeling patterns that maximize the number of unique pair assignments with a minimal number of differently labeled protein samples. Various auxiliary conditions, including labeled amino acid availability and price, previously known partial assignments, and sequence regions of particular interest can be taken into account when determining optimal amino acid type-specific labeling patterns. The method is illustrated for the assignment of the human G-protein coupled receptor bradykinin B2 (B 2 R) and applied as a starting point for the backbone assignment of the membrane protein proteorhodopsin.

  16. Chloroform-Methanol Residue of Coxiella burnetii Markedly Potentiated the Specific Immunoprotection Elicited by a Recombinant Protein Fragment rOmpB-4 Derived from Outer Membrane Protein B of Rickettsia rickettsii in C3H/HeN Mice.

    Directory of Open Access Journals (Sweden)

    Wenping Gong

    Full Text Available The obligate intracellular bacteria, Rickettsia rickettsii and Coxiella burnetii, are the potential agents of bio-warfare/bio-terrorism. Here C3H/HeN mice were immunized with a recombinant protein fragment rOmp-4 derived from outer membrane protein B, a major protective antigen of R. rickettsii, combined with chloroform-methanol residue (CMR extracted from phase I C. burnetii organisms, a safer Q fever vaccine. These immunized mice had significantly higher levels of IgG1 and IgG2a to rOmpB-4 and interferon-γ (IFN-γ and tumor necrosis factor-α (TNF-α, two crucial cytokines in resisting intracellular bacterial infection, as well as significantly lower rickettsial loads and slighter pathological lesions in organs after challenge with R. rickettsii, compared with mice immunized with rOmpB-4 or CMR alone. Additionally, after challenge with C. burnetii, the coxiella loads in the organs of these mice were significantly lower than those of mice immunized with rOmpB-4 alone. Our results prove that CMR could markedly potentiate enhance the rOmpB-4-specific immunoprotection by promoting specific and non-specific immunoresponses and the immunization with the protective antigen of R. rickettsii combined with CMR of C. burnetii could confer effective protection against infection of R. rickettsii or C. burnetii.

  17. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor; Villalobos Vazquez de la Parra, Luis Francisco; Hilke, Roland

    2015-01-01

    microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  18. Biophysical characterization of the Lactobacillus delbrueckii subsp. bulgaricus membrane during cold and osmotic stress and its relevance for cryopreservation.

    Science.gov (United States)

    Meneghel, Julie; Passot, Stéphanie; Dupont, Sébastien; Fonseca, Fernanda

    2017-02-01

    Freezing lactic acid bacteria often leads to cell death and loss of technological properties. Our objective was to provide an in-depth characterization of the biophysical properties of the Lactobacillus delbrueckii subsp. bulgaricus membrane in relation to its freeze resistance. Freezing was represented as a combination of cold and osmotic stress. This work investigated the relative incidence of increasing sucrose concentrations coupled or not with subzero temperatures without ice nucleation on the biological and biophysical responses of two strains with different membrane fatty acid compositions and freeze resistances. Following exposure of bacterial cells to the highest sucrose concentration, the sensitive strain exhibited a survival rate of less than 10 % and 5 h of acidifying activity loss. Similar biological activity losses were observed upon freeze-thawing and after osmotic treatment for each strain thus highlighting osmotic stress as the main source of cryoinjury. The direct measurement of membrane fluidity by fluorescence anisotropy was linked to membrane lipid organization characterized by FTIR spectroscopy. Both approaches made it possible to investigate the specific contributions of the membrane core and the bilayer external surface to cell degradation caused by cold and osmotic stress. Cold-induced membrane rigidification had no significant implication on bacterial freeze-thaw resistance. Interactions between extracellular sucrose and membrane phospholipid headgroups under osmotic stress were also observed. Such interactions were more evident in the sensitive strain and when increasing sucrose concentration, thus suggesting membrane permeabilization. The relevance of biophysical properties for elucidating mechanisms of cryoinjury and cryoprotection is discussed.

  19. Development of a Chlamydia suis-specific antibody enzyme-linked immunosorbent assay based on the use of a B-cell epitope of the polymorphic membrane protein C.

    Science.gov (United States)

    De Puysseleyr, K; Kieckens, E; De Puysseleyr, L; Van den Wyngaert, H; Ahmed, B; Van Lent, S; Creasy, H H; Myers, G S A; Vanrompay, D

    2018-04-01

    Chlamydia suis infections lead to economic loss in the pork industry. Chlamydia suis infections could be successfully treated with tetracyclines until the appearance of a tetracycline resistant phenotype, which was acquired via horizontal gene transfer of the tet(C) gene. Given the importance of C. suis as a swine pathogen and as a recently emerged tetracycline resistant pathogen with zoonotic potential, our aim was to develop a sensitive C. suis-specific antibody ELISA based on the polymorphic membrane proteins (Pmps). Chlamydia Pmps are important virulence factors and candidate antigens for serodiagnosis. We identified nine Pmps (PmpA to I) in C. suis strain MD56 using a recently developed Hidden-Markov model. PmpC was the most promising candidate for the development of a C. suis-specific antibody ELISA as the protein was absent in C. abortus, C. pecorum and C. psittaci which also infect pigs and as the protein contained C. suis-specific amino acid regions, absent in C. trachomatis PmpC. We identified an immunodominant B-cell epitope in C. suis PmpC using experimental porcine sera. The sensitivity and specificity of the PmpC ELISA was compared to the complement fixation test (CFT) and to a recombinant MOMP ELISA using experimental sera. The PmpC ELISA detected all positive control sera and was in contrast to CFT and the rMOMP ELISA 100% C. suis specific as positive control sera against other Chlamydia species did not react in the PmpC ELISA. The test was successfully validated using slaughterhouse sera and sera from clinically affected pigs. The PmpC ELISA could assist in diminishing the spread of C. suis infections in the pork industry. © 2018 Blackwell Verlag GmbH.

  20. Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Hingston, Patricia; Chen, Jessica; Allen, Kevin

    2017-01-01

    The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain....... This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA) profiling to characterize the bacterium’s cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more...... genes (1.3×) were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431) and magnitude (>1,000-fold) of differentially expressed genes (>2-fold, pcold. A core set of 22 genes was upregulated at all growth phases, including nine genes...

  1. Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes

    Science.gov (United States)

    Hingston, Patricia; Chen, Jessica; Allen, Kevin; Truelstrup Hansen, Lisbeth

    2017-01-01

    The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA) profiling to characterize the bacterium’s cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more genes (1.3×) were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431) and magnitude (>1,000-fold) of differentially expressed genes (>2-fold, pmonocytogenes, the growth-phase dependency of its cold-stress regulon, and the active roles of antisense transcripts in regulating its cold stress response. PMID:28662112

  2. Simultaneous mapping of membrane voltage and calcium in zebrafish heart in vivo reveals chamber-specific developmental transitions in ionic currents

    Directory of Open Access Journals (Sweden)

    Jennifer H Hou

    2014-09-01

    Full Text Available The cardiac action potential (AP and the consequent cytosolic Ca2+ transient are key indicators of cardiac function. Natural developmental processes, as well as many drugs and pathologies change the waveform, propagation, or variability (between cells or over time of these parameters. Here we apply a genetically encoded dual-function calcium and voltage reporter (CaViar to study the development of the zebrafish heart in vivo between 1.5 and 4 days post fertilization (dpf. We developed a high-sensitivity spinning disk confocal microscope and associated software for simultaneous three-dimensional optical mapping of voltage and calcium. We produced a transgenic zebrafish line expressing CaViar under control of the heart-specific cmlc2 promoter, and applied ion channel blockers at a series of developmental stages to map the maturation of the action potential in vivo. Early in development, the AP initiated via a calcium current through L-type calcium channels. Between 90 – 102 hours post fertilization (hpf, the ventricular AP switched to a sodium-driven upswing, while the atrial AP remained calcium driven. In the adult zebrafish heart, a sodium current drives the AP in both the atrium and ventricle. Simultaneous voltage and calcium imaging with genetically encoded reporters provides a new approach for monitoring cardiac development, and the effects of drugs on cardiac function.

  3. Mobile Variable Depth Sampling System Design Study

    International Nuclear Information System (INIS)

    BOGER, R.M.

    2000-01-01

    A design study is presented for a mobile, variable depth sampling system (MVDSS) that will support the treatment and immobilization of Hanford LAW and HLW. The sampler can be deployed in a 4-inch tank riser and has a design that is based on requirements identified in the Level 2 Specification (latest revision). The waste feed sequence for the MVDSS is based on Phase 1, Case 3S6 waste feed sequence. Technical information is also presented that supports the design study

  4. Mobile Variable Depth Sampling System Design Study

    Energy Technology Data Exchange (ETDEWEB)

    BOGER, R.M.

    2000-08-25

    A design study is presented for a mobile, variable depth sampling system (MVDSS) that will support the treatment and immobilization of Hanford LAW and HLW. The sampler can be deployed in a 4-inch tank riser and has a design that is based on requirements identified in the Level 2 Specification (latest revision). The waste feed sequence for the MVDSS is based on Phase 1, Case 3S6 waste feed sequence. Technical information is also presented that supports the design study.

  5. ISLSCP II Ecosystem Rooting Depths

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this study was to predict the global distribution of plant rooting depths based on data about global aboveground vegetation structure and climate....

  6. ISLSCP II Ecosystem Rooting Depths

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The goal of this study was to predict the global distribution of plant rooting depths based on data about global aboveground vegetation structure and...

  7. Membranes for Environmentally Friendly Energy Processes

    Science.gov (United States)

    He, Xuezhong; Hägg, May-Britt

    2012-01-01

    Membrane separation systems require no or very little chemicals compared to standard unit operations. They are also easy to scale up, energy efficient, and already widely used in various gas and liquid separation processes. Different types of membranes such as common polymers, microporous organic polymers, fixed-site-carrier membranes, mixed matrix membranes, carbon membranes as well as inorganic membranes have been investigated for CO2 capture/removal and other energy processes in the last two decades. The aim of this work is to review the membrane systems applied in different energy processes, such as post-combustion, pre-combustion, oxyfuel combustion, natural gas sweetening, biogas upgrading, hydrogen production, volatile organic compounds (VOC) recovery and pressure retarded osmosis for power generation. Although different membranes could probably be used in a specific separation process, choosing a suitable membrane material will mainly depend on the membrane permeance and selectivity, process conditions (e.g., operating pressure, temperature) and the impurities in a gas stream (such as SO2, NOx, H2S, etc.). Moreover, process design and the challenges relevant to a membrane system are also being discussed to illustrate the membrane process feasibility for a specific application based on process simulation and economic cost estimation. PMID:24958426

  8. Membranes for Environmentally Friendly Energy Processes

    Directory of Open Access Journals (Sweden)

    Xuezhong He

    2012-10-01

    Full Text Available Membrane separation systems require no or very little chemicals compared to standard unit operations. They are also easy to scale up, energy efficient, and already widely used in various gas and liquid separation processes. Different types of membranes such as common polymers, microporous organic polymers, fixed-site-carrier membranes, mixed matrix membranes, carbon membranes as well as inorganic membranes have been investigated for CO2 capture/removal and other energy processes in the last two decades. The aim of this work is to review the membrane systems applied in different energy processes, such as post-combustion, pre-combustion, oxyfuel combustion, natural gas sweetening, biogas upgrading, hydrogen production, volatile organic compounds (VOC recovery and pressure retarded osmosis for power generation. Although different membranes could probably be used in a specific separation process, choosing a suitable membrane material will mainly depend on the membrane permeance and selectivity, process conditions (e.g., operating pressure, temperature and the impurities in a gas stream (such as SO2, NOx, H2S, etc.. Moreover, process design and the challenges relevant to a membrane system are also being discussed to illustrate the membrane process feasibility for a specific application based on process simulation and economic cost estimation.

  9. Reference depth for geostrophic computation - A new method

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.; Sastry, J.S.

    Various methods are available for the determination of reference depth for geostrophic computation. A new method based on the vertical profiles of mean and variance of the differences of mean specific volume anomaly (delta x 10) for different layers...

  10. Structure and dynamics of cationic membrane peptides and proteins: Insights from solid-state NMR

    Science.gov (United States)

    Hong, Mei; Su, Yongchao

    2011-01-01

    Many membrane peptides and protein domains contain functionally important cationic Arg and Lys residues, whose insertion into the hydrophobic interior of the lipid bilayer encounters significant energy barriers. To understand how these cationic molecules overcome the free energy barrier to insert into the lipid membrane, we have used solid-state NMR spectroscopy to determine the membrane-bound topology of these peptides. A versatile array of solid-state NMR experiments now readily yields the conformation, dynamics, orientation, depth of insertion, and site-specific protein–lipid interactions of these molecules. We summarize key findings of several Arg-rich membrane peptides, including β-sheet antimicrobial peptides, unstructured cell-penetrating peptides, and the voltage-sensing helix of voltage-gated potassium channels. Our results indicate the central role of guanidinium-phosphate and guanidinium-water interactions in dictating the structural topology of these cationic molecules in the lipid membrane, which in turn account for the mechanisms of this functionally diverse class of membrane peptides. PMID:21344534

  11. Λ and Σ well depth

    International Nuclear Information System (INIS)

    Satoh, Eiji

    1982-01-01

    The Λ well depth was calculated by taking into account the effect of the ΛΣ conversion. Takahashi et al. obtained the separate type of potentials which described the hyperon-nucleon interaction up to p waves. Two types of the potentials among several types they obtained were used to calculate the Λ well depth. The G matrix was easily calculated, and the Λ well depth was obtained by integrating the G matrix in momentum space up to the Fermi surface. The effect of the ΛΣ conversion was given by an equation. The total Λ well depth was estimated to be 9.13 MeV and 49.36 MeV for each type of potential, respectively. It was concluded that the argument by Bodmer et al. was not correct. The Σ well depth was also calculated using the potential obtained by Takahashi et al. for I = 1/2 and the one obtained by Σ + p → Σ + p scattering data for I = 3/2. The obtained value 35.30 MeV may be overestimated, and the experimental value is expected to be in the range from 20 MeV to 30 MeV. (Ito, K.)

  12. Membrane modules for building ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Kistler, K.R.; Cussler, E.L.

    2002-01-01

    Hollow fibre and flat sheet membranes with an interfacially polymerized coating of polyamide have a permeance for water vapour of about 0.16 m sec{sup -1}. These membranes can serve as a basis for building ventilation which provides fresh air while recovering about 70% of the specific heat and 60% of the latent heat. Because these membranes are selective for water vapour, the air is exhausted with internal pollutants like carbon monoxide, formaldehyde, and radon. The expense of the ventilator should be recovered in reduced heating costs in about three years. (Author)

  13. Diagnostic Accuracy of 64Copper Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography for Primary Lymph Node Staging of Intermediate- to High-risk Prostate Cancer: Our Preliminary Experience.

    Science.gov (United States)

    Cantiello, Francesco; Gangemi, Vincenzo; Cascini, Giuseppe Lucio; Calabria, Ferdinando; Moschini, Marco; Ferro, Matteo; Musi, Gennaro; Butticè, Salvatore; Salonia, Andrea; Briganti, Alberto; Damiano, Rocco

    2017-08-01

    To assess the diagnostic accuracy of 64 Copper prostate-specific membrane antigen ( 64 Cu-PSMA) positron emission tomography/computed tomography (PET/CT) in the primary lymph node (LN) staging of a selected cohort of intermediate- to high-risk prostate cancer (PCa) patients. An observational prospective study was performed in 23 patients with intermediate- to high-risk PCa, who underwent 64 Cu-PSMA PET/CT for local and lymph nodal staging before laparoscopic radical prostatectomy with an extended pelvic LN dissection. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for LN status of 64 Cu-PSMA PET/CT were calculated using the final pathological findings as reference. Furthermore, we evaluated the correlation of intraprostatic tumor extent and grading with 64 Cu-PSMA intraprostatic distribution. Pathological analysis of LN involvement in 413 LNs harvested from our study cohort identified a total of 22 LN metastases in 8 (5%) of the 23 (35%) PCa patients. Imaging-based LN staging in a per-patient analysis showed that 64 Cu-PSMA PET/CT was positive in 7 of 8 LN-positive patients (22%) with a sensitivity of 87.5%, specificity of 100%, PPV of 100%, and NPV of 93.7%, considering the maximum standardized uptake value (SUV max ) at 4 hours as our reference. Receiver operating characteristic curve was characterized by an area under the curve of 0.938. A significant positive association was observed between SUV max at 4 hours with Gleason score, index, and cumulative tumor volume. In our intermediate- to high-risk PCa patients study cohort, we showed the high diagnostic accuracy of 64 Cu-PSMA PET/CT for primary LN staging before radical prostatectomy. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Dynamic nuclear polarization methods in solids and solutions to explore membrane proteins and membrane systems.

    Science.gov (United States)

    Cheng, Chi-Yuan; Han, Songi

    2013-01-01

    Membrane proteins regulate vital cellular processes, including signaling, ion transport, and vesicular trafficking. Obtaining experimental access to their structures, conformational fluctuations, orientations, locations, and hydration in membrane environments, as well as the lipid membrane properties, is critical to understanding their functions. Dynamic nuclear polarization (DNP) of frozen solids can dramatically boost the sensitivity of current solid-state nuclear magnetic resonance tools to enhance access to membrane protein structures in native membrane environments. Overhauser DNP in the solution state can map out the local and site-specific hydration dynamics landscape of membrane proteins and lipid membranes, critically complementing the structural and dynamics information obtained by electron paramagnetic resonance spectroscopy. Here, we provide an overview of how DNP methods in solids and solutions can significantly increase our understanding of membrane protein structures, dynamics, functions, and hydration in complex biological membrane environments.

  15. Spectrometric kidney depth measurement method

    International Nuclear Information System (INIS)

    George, P.; Soussaline, F.; Raynaud, C.

    1976-01-01

    The method proposed uses the single posterior surface measurement of the kidney radioactivity distribution. The ratio C/P of the number of scattered photons to the number of primary photons, which is a function of the tissue depth penetrated, is calculated for a given region. The parameters on which the C/P value depends are determined from studies on phantoms. On the basis of these results the kidney depth was measured on a series of 13 patients and a correlation was established between the value thus calculated and that obtained by the profile method. The reproducibility of the method is satisfactory [fr

  16. Heat flow of standard depth

    International Nuclear Information System (INIS)

    Cull, J.P.

    1981-01-01

    Secular and long-term periodic changes in surface temperature cause perturbations to the geothermal gradient which may be significant to depths of at least 1000 m, and major corrections are required to determine absolute values of heat flow from the Earth's interior. However, detailed climatic models remain contentious and estimates of error in geothermal gradients differ widely. Consequently, regions of anomalous heat flow which could contain geothermal resources may be more easily resolved by measuring relative values at a standard depth (e.g. 100 m) so that all data are subject to similar corrections. (orig./ME)

  17. Characterisation of adaptive fluidic silicone membrane lenses

    CSIR Research Space (South Africa)

    Schneider, F

    2009-09-01

    Full Text Available membrane shapes for a lens volume of 1 µl at divorce homogeneous membrane thicknesses. The measurement of the system behaviour is realized by the laser-profilometer in the dynamic mode. For the lens with a homogeneous membrane the membrane surface..., inhomogeneous membranes is application specific. On the one hand, systems with planar mem- branes are reasonable for a large focal length range, a constant optical lens quality and a short response time. On the other hand, the application of lenses...

  18. Carbon membranes - current progress and future prospects

    International Nuclear Information System (INIS)

    Tennison, St.; Arnott, K.; Richter, H.

    2007-01-01

    The future use of nano-porous gas separation membranes will be dependent on significant reductions in the membrane and module costs, improvements in production methods to allow better reproducibility, ability to scale up production and improved performance and understanding of the mode of operation of the membrane systems. New approaches to ceramic supported carbon membranes could offer solutions to these problems. Whilst the performance characteristics underline the limitations of these membranes they also show where specific process opportunities might be accessible particularly in environmental and high temperature separations. (authors)

  19. Pursuing the Depths of Knowledge

    Science.gov (United States)

    Boyles, Nancy

    2016-01-01

    Today's state literacy standards and assessments demand deeper levels of knowledge from students. But many teachers ask, "What does depth of knowledge look like on these new, more rigorous assessments? How do we prepare students for this kind of thinking?" In this article, Nancy Boyles uses a sampling of questions from the PARCC and SBAC…

  20. Polymeric membrane studied using slow positron beam

    International Nuclear Information System (INIS)

    Hung, W.-S.; Lo, C.-H.; Cheng, M.-L.; Chen Hongmin; Liu Guang; Chakka, Lakshmi; Nanda, D.; Tung, K.-L.; Huang, S.-H.; Lee, Kueir-Rarn; Lai, J.-Y.; Sun Yiming; Yu Changcheng; Zhang Renwu; Jean, Y.C.

    2008-01-01

    A radioisotope slow positron beam has been built at the Chung Yuan Christian University in Taiwan for the research and development in membrane science and technology. Doppler broadening energy spectra and positron annihilation lifetime have been measured as a function of positron energy up to 30 keV in a polyamide membrane prepared by the interfacial polymerization between triethylenetetraamine (TETA) and trimesoyl chloride (TMC) on modified porous polyacrylonitrile (PAN) asymmetric membrane. The multilayer structures and free-volume depth profile for this asymmetric membrane system are obtained. Positron annihilation spectroscopy coupled with a slow beam could provide new information about size selectivity of transporting molecules and guidance for molecular designs in polymeric membranes

  1. Silica incorporated membrane for wastewater based filtration

    Science.gov (United States)

    Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

    2017-10-01

    Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

  2. Hydrogen Selective Exfoliated Zeolite Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tsapatsis, Michael [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Daoutidis, Prodromos [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Elyassi, Bahman [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Lima, Fernando [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Iyer, Aparna [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Agrawal, Kumar [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Sabnis, Sanket [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science

    2015-04-06

    in terms of performance and economic aspects of the plants. Specifically, simulation and design optimization studies were performed using the developed stand-alone membrane reactor models to identify the membrane selectivity and permeance characteristics necessary to achieve desired targets of CO2 capture and H2 recovery, as well as guide the selection of the optimal reactor design that minimizes the membrane cost as a function of its surface area required. The isothermal membrane reactor model was also integrated into IGCC system models using both the MATLAB and Aspen software platforms and techno-economic analyses of the integrated plants have been carried out to evaluate the feasibility of replacing current technologies for pre-combustion capture by the proposed novel approach in terms of satisfying stream constraints and achieving the DOE target goal of 90% CO2 capture. The results of the performed analyses based on present value of annuity calculations showed break even costs for the membrane reactor within the feasible range for membrane fabrication. However, the predicted membrane performance used in these simulations exceeded the performance achieved experimentally. Therefore, further work is required to improve membrane performance.

  3. Robotic membranes

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette

    2008-01-01

    The relationship between digital and analogue is often constructed as one of opposition. The perception that the world is permeated with underlying patterns of data, describing events and matter alike, suggests that information can be understood apart from the substance to which it is associated......, and that its encoded logic can be constructed and reconfigured as an isolated entity. This disembodiment of information from materiality implies that an event like a thunderstorm, or a material like a body, can be described equally by data, in other words it can be read or written. The following prototypes......, Vivisection and Strange Metabolisms, were developed at the Centre for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts in Copenhagen as a means of engaging intangible digital data with tactile physical material. As robotic membranes, they are a dual examination...

  4. Perforate on CHO cell membranes induced by electromagnetic ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-17

    Jun 17, 2009 ... Key words: Electromagnetic pulse (EMP), atomic force microscope, CHO cell, cell membrane. INTRODUCTION .... of perforation ranges from 390 to 660 nm and the depth is. 392.95 nm. ... cell membrane perforations increased when both the field intensity and ..... Melatonin and a spin-trap compound block.

  5. Intercomparison On Depth Dose Measurement

    International Nuclear Information System (INIS)

    Rohmah, N; Akhadi, M

    1996-01-01

    Intercomparation on personal dose evaluation system has been carried out between CSRSR-NAEA of Indonesia toward Standard Laboratory of JAERI (Japan) and ARL (Australia). The intercomparison was in 10 amm depth dose measurement , Hp (10), from the intercomparison result could be stated that personal depth dose measurement conducted by CSRSR was sufficiently good. Deviation of dose measurement result using personal dosemeter of TLD BG-1 type which were used by CSRSR in the intercomparison and routine photon personal dose monitoring was still in internationally agreed limit. Maximum deviation of reported doses by CSRSR compared to delivered doses for dosemeter irradiation by JAERI was -10.0 percent and by ARL was +29 percent. Maximum deviation permitted in personal dose monitoring is ± 50 percent

  6. Applications of positron depth profiling

    International Nuclear Information System (INIS)

    Hakvoort, R.A.

    1993-01-01

    In this thesis some contributions of the positron-depth profiling technique to materials science have been described. Following studies are carried out: Positron-annihilation measurements on neon-implanted steel; Void creation in silicon by helium implantation; Density of vacancy-type defects present in amorphous silicon prepared by ion implantation; Measurements of other types of amorphous silicon; Epitaxial cobalt disilicide prepared by cobalt outdiffusion. Positron-annihilation experiments on low-pressure CVD silicon-nitride films. (orig./MM)

  7. Applications of positron depth profiling

    Energy Technology Data Exchange (ETDEWEB)

    Hakvoort, R A

    1993-12-23

    In this thesis some contributions of the positron-depth profiling technique to materials science have been described. Following studies are carried out: Positron-annihilation measurements on neon-implanted steel; Void creation in silicon by helium implantation; Density of vacancy-type defects present in amorphous silicon prepared by ion implantation; Measurements of other types of amorphous silicon; Epitaxial cobalt disilicide prepared by cobalt outdiffusion. Positron-annihilation experiments on low-pressure CVD silicon-nitride films. (orig./MM).

  8. Highly antifouling and antibacterial performance of poly (vinylidene fluoride) ultrafiltration membranes blending with copper oxide and graphene oxide nanofillers for effective wastewater treatment.

    Science.gov (United States)

    Zhao, Chuanqi; Lv, Jinling; Xu, Xiaochen; Zhang, Guoquan; Yang, Yuesuo; Yang, Fenglin

    2017-11-01

    Innovation and effective wastewater treatment technology is still in great demand given the emerging contaminants frequently spotted from the aqueous environment. By blending with poly (vinylidene fluoride) (PVDF), the strong hydrophilic graphene oxide (GO) and antibacterial copper oxide (Cu x O) were used as nanofillers to develop the novel, highly antifouling composite membranes via phase inversion process in our latest work. The existence and dispersion of GO and Cu x O posed a significant role on morphologies, structures, surface composition and hydrophilicity of the developed composite membranes, confirmed by SEM, TEM, FTIR and XPS in depth characterization. The SEM images showed that the modified membranes presented a lower resistant structure with developed finger-like macrovoids and thin-walled even interconnected sponge-like pores after adding nanofillers, much encouraging membrane permeation. The XPS results revealed that Cu x O contained Cu 2 O and CuO in the developed membrane and the Cu 2 O nanoparticles were dominant accounting for about 79.3%; thus the modified membrane specifically exhibited an efficient antibacterial capacity. Due to the hydrophilic and bactericidal membrane surface, the composite membranes demonstrated an excellent antifouling performance, including higher flux recovery rate, more resistant against accumulated contaminants and lower filtration resistance, especially lower irreversible resistance. The antifouling property, especially anti-irreversible fouling, was significantly improved, showing a significant engineering potential. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. A plasma membrane H + ATPase gene is germinationinduced in ...

    African Journals Online (AJOL)

    A plasma membrane H + ATPase gene is germinationinduced in wheat embryos. ... African Journal of Biotechnology ... of a germination specific plasma membrane H+-ATPase was analyzed by RTPCR and in situ RNA hybridization methods.

  10. Regulation of HIV-Gag Expression and Targeting to the Endolysosomal/Secretory Pathway by the Luminal Domain of Lysosomal-Associated Membrane Protein (LAMP-1) Enhance Gag-Specific Immune Response

    Science.gov (United States)

    Lucas, Carolina Gonçalves de Oliveira; Rigato, Paula Ordonhez; Gonçalves, Jorge Luiz Santos; Sato, Maria Notomi; Maciel, Milton; Peçanha, Ligia Maria Torres; August, J. Thomas; de Azevedo Marques, Ernesto Torres; de Arruda, Luciana Barros

    2014-01-01

    We have previously demonstrated that a DNA vaccine encoding HIV-p55gag in association with the lysosomal associated membrane protein-1 (LAMP-1) elicited a greater Gag-specific immune response, in comparison to a DNA encoding the native gag. In vitro studies have also demonstrated that LAMP/Gag was highly expressed and was present in MHCII containing compartments in transfected cells. In this study, the mechanisms involved in these processes and the relative contributions of the increased expression and altered traffic for the enhanced immune response were addressed. Cells transfected with plasmid DNA constructs containing p55gag attached to truncated sequences of LAMP-1 showed that the increased expression of gag mRNA required p55gag in frame with at least 741 bp of the LAMP-1 luminal domain. LAMP luminal domain also showed to be essential for Gag traffic through lysosomes and, in this case, the whole sequence was required. Further analysis of the trafficking pathway of the intact LAMP/Gag chimera demonstrated that it was secreted, at least in part, associated with exosome-like vesicles. Immunization of mice with LAMP/gag chimeric plasmids demonstrated that high expression level alone can induce a substantial transient antibody response, but targeting of the antigen to the endolysosomal/secretory pathways was required for establishment of cellular and memory response. The intact LAMP/gag construct induced polyfunctional CD4+ T cell response, which presence at the time of immunization was required for CD8+ T cell priming. LAMP-mediated targeting to endolysosomal/secretory pathway is an important new mechanistic element in LAMP-mediated enhanced immunity with applications to the development of novel anti-HIV vaccines and to general vaccinology field. PMID:24932692

  11. A general model for membrane-based separation processes

    DEFF Research Database (Denmark)

    Soni, Vipasha; Abildskov, Jens; Jonsson, Gunnar Eigil

    2009-01-01

    behaviour will play an important role. In this paper, modelling of membrane-based processes for separation of gas and liquid mixtures are considered. Two general models, one for membrane-based liquid separation processes (with phase change) and another for membrane-based gas separation are presented....... The separation processes covered are: membrane-based gas separation processes, pervaporation and various types of membrane distillation processes. The specific model for each type of membrane-based process is generated from the two general models by applying the specific system descriptions and the corresponding...

  12. Development and Applications of Time of Flight Neutron Depth Profiling

    International Nuclear Information System (INIS)

    Cady, Bingham; Unlu, Kenan

    2005-01-01

    The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. For example, the subtle differences in spatial distribution and composition of many chemical species in the near surface region and across interfacial boundaries can significantly alter the electronic and optical properties of materials. A number of analytical techniques for depth profiling have been developed during the last two decades. neutron Depth Profiling (NDP) is one of the leading analytical techniques. The NDP is a nondestructive near surface technique that utilizes thermal/cold neutron beam to measure the concentration of specific light elements versus their depth in materials. The depth is obtained from the energy loss of protons, alphas or recoil atoms in substrate materials. Since the charged particle energy determination using surface barrier detector is used for NDP, the depth resolution is highly dependent on the detectors an d detection instruments. The depth resolutions of a few tens of nm are achieved with available NDP facilities in the world. However, the performance of NDP needs to be improved in order to obtain a few A depth resolutions

  13. Magnitude, precision, and realism of depth perception in stereoscopic vision.

    Science.gov (United States)

    Hibbard, Paul B; Haines, Alice E; Hornsey, Rebecca L

    2017-01-01

    Our perception of depth is substantially enhanced by the fact that we have binocular vision. This provides us with more precise and accurate estimates of depth and an improved qualitative appreciation of the three-dimensional (3D) shapes and positions of objects. We assessed the link between these quantitative and qualitative aspects of 3D vision. Specifically, we wished to determine whether the realism of apparent depth from binocular cues is associated with the magnitude or precision of perceived depth and the degree of binocular fusion. We presented participants with stereograms containing randomly positioned circles and measured how the magnitude, realism, and precision of depth perception varied with the size of the disparities presented. We found that as the size of the disparity increased, the magnitude of perceived depth increased, while the precision with which observers could make depth discrimination judgments decreased. Beyond an initial increase, depth realism decreased with increasing disparity magnitude. This decrease occurred well below the disparity limit required to ensure comfortable viewing.

  14. Conditions that allow for effective transfer of membrane proteins onto nitrocellulose membrane in Western blots.

    Science.gov (United States)

    Abeyrathne, Priyanka D; Lam, Joseph S

    2007-04-01

    A major hurdle in characterizing bacterial membrane proteins by Western blotting is the ineffectiveness of transferring these proteins from sodium dodecyl sulfate -- polyacrylamide gel electrophoresis (SDS-PAGE) gel onto nitrocellulose membrane, using standard Western blot buffers and electrophoretic conditions. In this study, we compared a number of modified Western blotting buffers and arrived at a composition designated as the SDS-PAGE-Urea Lysis buffer. The use of this buffer and specific conditions allowed the reproducible transfer of highly hydrophobic bacterial membrane proteins with 2-12 transmembrane-spanning segments as well as soluble proteins onto nitrocellulose membranes. This method should be broadly applicable for immunochemical studies of other membrane proteins.

  15. Sensing Phosphatidylserine in Cellular Membranes

    Directory of Open Access Journals (Sweden)

    Jason G. Kay

    2011-01-01

    Full Text Available Phosphatidylserine, a phospholipid with a negatively charged head-group, is an important constituent of eukaryotic cellular membranes. On the plasma membrane, rather than being evenly distributed, phosphatidylserine is found preferentially in the inner leaflet. Disruption of this asymmetry, leading to the appearance of phosphatidylserine on the surface of the cell, is known to play a central role in both apoptosis and blood clotting. Despite its importance, comparatively little is known about phosphatidylserine in cells: its precise subcellular localization, transmembrane topology and intracellular dynamics are poorly characterized. The recent development of new, genetically-encoded probes able to detect phosphatidylserine within live cells, however, is leading to a more in-depth understanding of the biology of this phospholipid. This review aims to give an overview of the current methods for phosphatidylserine detection within cells, and some of the recent realizations derived from their use.

  16. GNF Defense in Depth Update

    Energy Technology Data Exchange (ETDEWEB)

    Lingenfelter, Andrew A.; Schneider, Robert J.; Cantonwine, Paul E.; Moore, Brian; Rea, John; Crawford, Douglas C. [Global Nuclear Fuel, P.O. Box 780 M/C H25, Wilmington, NC 28402 (United States)

    2009-06-15

    Global Nuclear Fuel (GNF) has designed, fabricated, and placed into operation more than 9 million fuel rods in approximately 135 thousand assemblies. Customer satisfaction has always compelled GNF to reduce fuel rod failures (defined here as fuel rods that breach or leak in service), However, increasing success with and subsequent expectations for economic performance of nuclear reactor plants have raised broader Industry emphasis on fuel reliability. In 2005, GNF established its Defense-in-Depth (DID) Program for the purpose of focusing attention on the many aspects of fuel design, fabrication, performance, and utilization that affect fuel reliability as well as on the key methods that govern the utilization of GNF fuel. The Program is structured to address each of the identified in-service, fuel failure mechanisms. This paper provides a summary of GNF fuel performance, following previous updates. This paper will discuss recent GNF fuel reliability and channel performance, GNF2 introduction status, and methods. GNF's more recent fuel experience includes approximately 3.8 million GE11/13 (9x9) and GE12/14 (10x10) fuel rods, well over half of which are the GE12/14 design. (Those figures also include roughly 25,000 recently-introduced GNF2 fuel rods.) Reliability, expressed as annual, observed fuel failure rates (i.e., number of rods failed each year divided by the number of opportunities, or fuel rods in service), has improved for each year since 2005. The GNF fuel failure rate for years leading up to 2007 and 2008 has been on the order of 5 to 7 ppm (excluding the corrosion events of 2001-2003), and as of this writing (January 2009) the current in-service failure has decreased to around 1.5 ppm. Failures in GE14 fuel rod failures have been primarily due to debris-fretting (> 60%), with other failures being duty-related or yet undetermined. The only failure observed in GNF2 to date was a single, early-life debris failure in a bundle not equipped with GNF

  17. Recent advances on polymeric membranes for membrane reactors

    KAUST Repository

    Buonomenna, M. G.; Choi, Seung Hak

    2012-01-01

    . The successful use of membranes in membrane reactors is primary the result of two developments concerning: (i) membrane materials and (ii) membrane structures. The selection of a suited material and preparation technique depends on the application the membrane

  18. Membrane-based technologies for biogas separations.

    Science.gov (United States)

    Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

    2010-02-01

    Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

  19. Light Responsive Polymer Membranes: A Review

    Directory of Open Access Journals (Sweden)

    Fiore Pasquale Nicoletta

    2012-03-01

    Full Text Available In recent years, stimuli responsive materials have gained significant attention in membrane separation processes due to their ability to change specific properties in response to small external stimuli, such as light, pH, temperature, ionic strength, pressure, magnetic field, antigen, chemical composition, and so on. In this review, we briefly report recent progresses in light-driven materials and membranes. Photo-switching mechanisms, valved-membrane fabrication and light-driven properties are examined. Advances and perspectives of light responsive polymer membranes in biotechnology, chemistry and biology areas are discussed.

  20. Molecular organization in bacterial cell membranes

    International Nuclear Information System (INIS)

    Larraga, V.; Munoz, E.

    1975-01-01

    The paper reports about an investigation into the question of the specific labelling and topological distribution of glycoproteins and proteins in Streptomyces albus membranes. The method of sample preparation is described: Tritium labelling of glycoproteins in protoplasts and membranes, iodination of proteins, trypsin treatment and polyacrylamide gel electrophoresis. The findings suggest an asymmetrical distribution of the glycoproteins in membranes and a weak accessibility to iodine label. A structural model of the plasma membranes of Streptomyces albus is proposed similar to the general 'fluid mosaic' model of Singer and Nicholson. (BSC) [de

  1. Magnetically controlled permeability membranes

    KAUST Repository

    Kosel, Jurgen

    2013-10-31

    A bioactive material delivery system can include a thermoresponsive polymer membrane and nanowires distributed within the thermoresponsive polymer membrane. Magnetic activation of a thermoresponsive polymer membrane can take place via altering the magnetization or dimensions of nanowires dispersed or ordered within the membrane matrix.

  2. Magnetically controlled permeability membranes

    KAUST Repository

    Kosel, Jü rgen; Khashab, Niveen M.; Zaher, Amir

    2013-01-01

    A bioactive material delivery system can include a thermoresponsive polymer membrane and nanowires distributed within the thermoresponsive polymer membrane. Magnetic activation of a thermoresponsive polymer membrane can take place via altering the magnetization or dimensions of nanowires dispersed or ordered within the membrane matrix.

  3. Distribution in depth of quasars

    International Nuclear Information System (INIS)

    Schmidt, M.; Green, R.F.

    1980-01-01

    The authors discuss the distribution in depth of different kinds of quasars: quasi-stellar radio sources with steep radio spectrum, those with flat radio spectrum, and optically selected quasars. All exhibit an increase of space density with distance to a different degree. The optically selected quasars, in particular, show a steep increase of surface density with magnitude. The steepness of the increase is inconsistent with a uniform distribution of quasars in the local hypothesis. In the cosmological hypothesis the co-moving space density of optically selected quasars increases by a factor of 100,000 to a redshift of 2, and by factors of 1000 and 10 for steep-spectrum and flat-spectrum radio quasars, respectively. (Auth.)

  4. Simplicial band depth for multivariate functional data

    KAUST Repository

    López-Pintado, Sara

    2014-03-05

    We propose notions of simplicial band depth for multivariate functional data that extend the univariate functional band depth. The proposed simplicial band depths provide simple and natural criteria to measure the centrality of a trajectory within a sample of curves. Based on these depths, a sample of multivariate curves can be ordered from the center outward and order statistics can be defined. Properties of the proposed depths, such as invariance and consistency, can be established. A simulation study shows the robustness of this new definition of depth and the advantages of using a multivariate depth versus the marginal depths for detecting outliers. Real data examples from growth curves and signature data are used to illustrate the performance and usefulness of the proposed depths. © 2014 Springer-Verlag Berlin Heidelberg.

  5. Soil water availability and rooting depth as determinants of hydraulic architecture of Patagonian woody species

    Science.gov (United States)

    Sandra J. Bucci; Fabian G. Scholz; Guillermo Goldstein; Frederick C. Meinzer; Maria E. Arce

    2009-01-01

    We studied the water economy of nine woody species differing in rooting depth in a Patagonian shrub steppe from southern Argentina to understand how soil water availability and rooting depth determine their hydraulic architecture. Soil water content and potentials, leaf water potentials (Leaf) hydraulic conductivity, wood density (Pw), rooting depth, and specific leaf...

  6. [Germ cell membrane lipids in spermatogenesis].

    Science.gov (United States)

    Wang, Ting; Shi, Xiao; Quan, Song

    2016-05-01

    Spermatogenesis is a complex developmental process in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. During spermatogenesis, membrane remodeling takes place, and cell membrane permeability and liquidity undergo phase-specific changes, which are all associated with the alteration of membrane lipids. Lipids are important components of the germ cell membrane, whose volume and ratio fluctuate in different phases of spermatogenesis. Abnormal lipid metabolism can cause spermatogenic dysfunction and consequently male infertility. Germ cell membrane lipids are mainly composed of cholesterol, phospholipids and glycolipids, which play critical roles in cell adhesion and signal transduction during spermatogenesis. An insight into the correlation of membrane lipids with spermatogenesis helps us to better understand the mechanisms of spermatogenesis and provide new approaches to the diagnosis and treatment of male infertility.

  7. Pre-therapeutic dosimetry of normal organs and tissues of {sup 177}Lu-PSMA-617 prostate-specific membrane antigen (PSMA) inhibitor in patients with castration-resistant prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kabasakal, Levent; AbuQbeitah, Mohammad; Ayguen, Aslan; Yeyin, Nami [Istanbul University, Department of Nuclear Medicine, Cerrahpasa Medical Faculty, Istanbul (Turkey); Ocak, Meltem [Istanbul University, Department of Pharmaceutical Technology, Pharmacy Faculty, Istanbul (Turkey); Demirci, Emre [Sisli Etfal Training and Research Hospital, Department of Nuclear Medicine, Istanbul (Turkey); Toklu, Turkay [Yeditepe University Medical Faculty, Department of Nuclear Medicine, Istanbul (Turkey)

    2015-12-15

    {sup 177}Lu-617-prostate-specific membrane antigen (PSMA) ligand seems to be a promising tracer for radionuclide therapy of progressive prostate cancer. However, there are no published data regarding the radiation dose given to the normal tissues. The aim of the present study was to estimate the pretreatment radiation doses in patients who will undergo radiometabolic therapy using a tracer amount of {sup 177}Lu-labeled PSMA ligand. The study included seven patients with progressive prostate cancer with a mean age of 63.9 ± 3.9 years. All patients had prior PSMA positron emission tomography (PET) imaging and had intense tracer uptake at the lesions. The injected {sup 177}Lu-PSMA-617 activity ranged from 185 to 210 MBq with a mean of 192.6 ± 11.0 MBq. To evaluate bone marrow absorbed dose 2-cc blood samples were withdrawn in short variable times (3, 15, 30, 60, and 180 min and 24, 48, and 120 h) after injection. Whole-body images were obtained at 4, 24, 48, and 120 h post-injection (p.i.). The geometric mean of anterior and posterior counts was determined through region of interest (ROI) analysis. Attenuation correction was applied using PSMA PET/CT images. The OLINDA/EXM dosimetry program was used for curve fitting, residence time calculation, and absorbed dose calculations. The calculated radiation-absorbed doses for each organ showed substantial variation. The highest radiation estimated doses were calculated for parotid glands and kidneys. Calculated radiation-absorbed doses per megabecquerel were 1.17 ± 0.31 mGy for parotid glands and 0.88 ± 0.40 mGy for kidneys. The radiation dose given to the bone marrow was significantly lower than those of kidney and parotid glands (p < 0.05). The calculated radiation dose to bone marrow was 0.03 ± 0.01 mGy/MBq. Our first results suggested that {sup 177}Lu-PSMA-617 therapy seems to be a safe method. The dose-limiting organ seems to be the parotid glands rather than kidneys and bone marrow. The lesion radiation doses are

  8. Scales of snow depth variability in high elevation rangeland sagebrush

    Science.gov (United States)

    Tedesche, Molly E.; Fassnacht, Steven R.; Meiman, Paul J.

    2017-09-01

    In high elevation semi-arid rangelands, sagebrush and other shrubs can affect transport and deposition of wind-blown snow, enabling the formation of snowdrifts. Datasets from three field experiments were used to investigate the scales of spatial variability of snow depth around big mountain sagebrush ( Artemisia tridentata Nutt.) at a high elevation plateau rangeland in North Park, Colorado, during the winters of 2002, 2003, and 2008. Data were collected at multiple resolutions (0.05 to 25 m) and extents (2 to 1000 m). Finer scale data were collected specifically for this study to examine the correlation between snow depth, sagebrush microtopography, the ground surface, and the snow surface, as well as the temporal consistency of snow depth patterns. Variograms were used to identify the spatial structure and the Moran's I statistic was used to determine the spatial correlation. Results show some temporal consistency in snow depth at several scales. Plot scale snow depth variability is partly a function of the nature of individual shrubs, as there is some correlation between the spatial structure of snow depth and sagebrush, as well as between the ground and snow depth. The optimal sampling resolution appears to be 25-cm, but over a large area, this would require a multitude of samples, and thus a random stratified approach is recommended with a fine measurement resolution of 5-cm.

  9. Assessment of defence in depth for nuclear power plants

    International Nuclear Information System (INIS)

    2005-01-01

    Defence in depth is a comprehensive approach to safety that has been developed by nuclear power experts to ensure with high confidence that the public and the environment are protected from any hazards posed by the use of nuclear power for the generation of electricity. The concepts of defence in depth and safety culture have served the nuclear power industry well as a basic philosophy for the safe design and operation of nuclear power plants. Properly applied, defence in depth ensures that no single human error or equipment failure at one level of defence, nor even a combination of failures at more than one level of defence, propagates to jeopardize defence in depth at the subsequent level or leads to harm to the public or the environment. The importance of the concept of defence in depth is underlined in IAEA Safety Standards, in particular in the requirements set forth in the Safety Standards: Safety of Nuclear Power Plants: Design (NS-R-1) and Safety Assessment and Verification for Nuclear Power Plants (NS-G-1.2). A specific report, Defence in Depth in Nuclear Safety (INSAG-10), describes the objectives, strategy, implementation and future development in the area of defence in depth in nuclear and radiation safety. In the report Basic Safety Principles for Nuclear Power Plants (INSAG-12), defence in depth is recognized as one of the fundamental safety principles that underlie the safety of nuclear power plants. In consonance with those high level publications, this Safety Report provides more specific technical information on the implementation of this concept in the siting, design, construction and operation of nuclear power plants. It describes a method for comprehensive and balanced review of the provisions required for implementing defence in depth in existing plants. This publication is intended to provide guidance primarily for the self-assessment by plant operators of the comprehensiveness and quality of defence in depth provisions. It can be used

  10. Next Generation Nuclear Plant Defense-in-Depth Approach

    International Nuclear Information System (INIS)

    Wallace, Edward G.; Fleming, Karl N.; Burns, Edward M.

    2009-01-01

    The purpose of this paper is to (1) document the definition of defense-in-depth and the pproach that will be used to assure that its principles are satisfied for the NGNP project and (2) identify the specific questions proposed for preapplication discussions with the NRC. Defense-in-depth is a safety philosophy in which multiple lines of defense and conservative design and evaluation methods are applied to assure the safety of the public. The philosophy is also intended to deliver a design that is tolerant to uncertainties in knowledge of plant behavior, component reliability or operator performance that might compromise safety. This paper includes a review of the regulatory foundation for defense-in-depth, a definition of defense-in-depth that is appropriate for advanced reactor designs based on High Temperature Gas-cooled Reactor (HTGR) technology, and an explanation of how this safety philosophy is achieved in the NGNP.

  11. Design studies of a depth encoding large aperture PET camera

    International Nuclear Information System (INIS)

    Moisan, C.; Rogers, J.G.; Buckley, K.R.; Ruth, T.J.; Stazyk, M.W.; Tsang, G.

    1994-10-01

    The feasibility of a wholebody PET tomograph with the capacity to correct for the parallax error induced by the Depth-Of-Interaction of γ-rays is assessed through simulation. The experimental energy, depth, and transverse position resolutions of BGO block detector candidates are the main inputs to a simulation that predicts the point source resolution of the Depth Encoding Large Aperture Camera (DELAC). The results indicate that a measured depth resolution of 7 mm (FWHM) is sufficient to correct a substantial part of the parallax error for a point source at the edge of the Field-Of-View. A search for the block specifications and camera ring radius that would optimize the spatial resolution and its uniformity across the Field-Of-View is also presented. (author). 10 refs., 1 tab., 5 figs

  12. EOP TDRs (Temperature-Depth-Recordings) Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature-depth-recorders (TDRs) were attached to commercial longline and research Cobb trawl gear to obtain absolute depth and temperature measurement during...

  13. Simplicial band depth for multivariate functional data

    KAUST Repository

    Ló pez-Pintado, Sara; Sun, Ying; Lin, Juan K.; Genton, Marc G.

    2014-01-01

    sample of curves. Based on these depths, a sample of multivariate curves can be ordered from the center outward and order statistics can be defined. Properties of the proposed depths, such as invariance and consistency, can be established. A simulation

  14. OBSERVABILITY-IN-DEPTH: AN ESSENTIAL COMPLEMENT TO THE DEFENSE-IN-DEPTH SAFETY STRATEGY IN THE NUCLEAR INDUSTRY1

    Directory of Open Access Journals (Sweden)

    FRANCESCA M. FAVARÒ

    2014-12-01

    We examine several “event reports” from the U.S. Nuclear Regulatory Commission database, which illustrate specific instances of violation of the observability-in-depth safety principle and the consequences that followed (e.g., unmonitored releases and loss of containments. We also revisit the Three Mile Island accident in light of the proposed principle, and identify causes and consequences of the lack of observability-in-depth related to this accident sequence. We illustrate both the benefits of adopting the observability-in-depth safety principle and the adverse consequences when this principle is violated or not implemented. This work constitutes a first step in the development of the observability-in-depth safety principle, and we hope this effort invites other researchers and safety professionals to further explore and develop this principle and its implementation.

  15. Gaspe hole sets depth record

    Energy Technology Data Exchange (ETDEWEB)

    1970-03-09

    The deepest diamond-cored hole in the Western Hemisphere, Gulf Sunnybank No. 1 on the Gaspe Peninsula of Quebec, has been completed at a depth of 11,600 ft. This is the deepest cored hole to be drilled anywhere in search of oil and gas production, and the deepest to be drilled using a wire-line core recovery technique. The well was completed in 183 days, and was cored continuously below the surface casing which was set and cemented at 1,004 ft. After underreaming a portion of the bottom of the hole, intermediate casing was set and cemented at 8,000 ft as a safety precaution against possible high oil or gas-fluid pressure. Actual coring time, after deducting time for underreaming and casing operations, was 152 days. Because of the cost of transporting a conventional oil-drilling rig to the E. location, the 89-ft mining rig was modified for the project. The contractor was Heath and Sherwood Drilling (Western) Ltd.

  16. Dynamic shaping of cellular membranes by phospholipids and membrane-deforming proteins.

    Science.gov (United States)

    Suetsugu, Shiro; Kurisu, Shusaku; Takenawa, Tadaomi

    2014-10-01

    All cellular compartments are separated from the external environment by a membrane, which consists of a lipid bilayer. Subcellular structures, including clathrin-coated pits, caveolae, filopodia, lamellipodia, podosomes, and other intracellular membrane systems, are molded into their specific submicron-scale shapes through various mechanisms. Cells construct their micro-structures on plasma membrane and execute vital functions for life, such as cell migration, cell division, endocytosis, exocytosis, and cytoskeletal regulation. The plasma membrane, rich in anionic phospholipids, utilizes the electrostatic nature of the lipids, specifically the phosphoinositides, to form interactions with cytosolic proteins. These cytosolic proteins have three modes of interaction: 1) electrostatic interaction through unstructured polycationic regions, 2) through structured phosphoinositide-specific binding domains, and 3) through structured domains that bind the membrane without specificity for particular phospholipid. Among the structured domains, there are several that have membrane-deforming activity, which is essential for the formation of concave or convex membrane curvature. These domains include the amphipathic helix, which deforms the membrane by hemi-insertion of the helix with both hydrophobic and electrostatic interactions, and/or the BAR domain superfamily, known to use their positively charged, curved structural surface to deform membranes. Below the membrane, actin filaments support the micro-structures through interactions with several BAR proteins as well as other scaffold proteins, resulting in outward and inward membrane micro-structure formation. Here, we describe the characteristics of phospholipids, and the mechanisms utilized by phosphoinositides to regulate cellular events. We then summarize the precise mechanisms underlying the construction of membrane micro-structures and their involvements in physiological and pathological processes. Copyright © 2014 the

  17. Selective effect of cell membrane on synaptic neurotransmission

    DEFF Research Database (Denmark)

    Postila, Pekka A.; Vattulainen, Ilpo; Róg, Tomasz

    2016-01-01

    Atomistic molecular dynamics simulations were performed with 13 non-peptidic neurotransmitters (NTs) in three different membrane environments. The results provide compelling evidence that NTs are divided into membrane-binding and membrane-nonbinding molecules. NTs adhere to the postsynaptic membr...... the importance of cell membrane and specific lipids for neurotransmission, should to be of interest to neuroscientists, drug industry and the general public alike.......Atomistic molecular dynamics simulations were performed with 13 non-peptidic neurotransmitters (NTs) in three different membrane environments. The results provide compelling evidence that NTs are divided into membrane-binding and membrane-nonbinding molecules. NTs adhere to the postsynaptic...... membrane surface whenever the ligand-binding sites of their synaptic receptors are buried in the lipid bilayer. In contrast, NTs that have extracellular ligand-binding sites do not have a similar tendency to adhere to the membrane surface. This finding is a seemingly simple yet important addition...

  18. Anionic lipids and the maintenance of membrane electrostatics in eukaryotes.

    Science.gov (United States)

    Platre, Matthieu Pierre; Jaillais, Yvon

    2017-02-01

    A wide range of signaling processes occurs at the cell surface through the reversible association of proteins from the cytosol to the plasma membrane. Some low abundant lipids are enriched at the membrane of specific compartments and thereby contribute to the identity of cell organelles by acting as biochemical landmarks. Lipids also influence membrane biophysical properties, which emerge as an important feature in specifying cellular territories. Such parameters are crucial for signal transduction and include lipid packing, membrane curvature and electrostatics. In particular, membrane electrostatics specifies the identity of the plasma membrane inner leaflet. Membrane surface charges are carried by anionic phospholipids, however the exact nature of the lipid(s) that powers the plasma membrane electrostatic field varies among eukaryotes and has been hotly debated during the last decade. Herein, we discuss the role of anionic lipids in setting up plasma membrane electrostatics and we compare similarities and differences that were found in different eukaryotic cells.

  19. Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers

    KAUST Repository

    Chu, Shidong; Maltsev, Sergey B.; Emwas, Abdul-Hamid M.; Lorigan, Gary A.

    2010-01-01

    A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2

  20. Visual Discomfort and Depth-of-Field

    Directory of Open Access Journals (Sweden)

    Louise O'Hare

    2013-05-01

    Full Text Available Visual discomfort has been reported for certain visual stimuli and under particular viewing conditions, such as stereoscopic viewing. In stereoscopic viewing, visual discomfort can be caused by a conflict between accommodation and convergence cues that may specify different distances in depth. Earlier research has shown that depth-of-field, which is the distance range in depth in the scene that is perceived to be sharp, influences both the perception of egocentric distance to the focal plane, and the distance range in depth between objects in the scene. Because depth-of-field may also be in conflict with convergence and the accommodative state of the eyes, we raised the question of whether depth-of-field affects discomfort when viewing stereoscopic photographs. The first experiment assessed whether discomfort increases when depth-of-field is in conflict with coherent accommodation–convergence cues to distance in depth. The second experiment assessed whether depth-of-field influences discomfort from a pre-existing accommodation–convergence conflict. Results showed no effect of depth-of-field on visual discomfort. These results suggest therefore that depth-of-field can be used as a cue to depth without inducing discomfort in the viewer, even when cue conflicts are large.

  1. Synthetic membrane-targeted antibiotics.

    Science.gov (United States)

    Vooturi, S K; Firestine, S M

    2010-01-01

    Antimicrobial resistance continues to evolve and presents serious challenges in the therapy of both nosocomial and community-acquired infections. The rise of resistant strains like methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA) and vancomycin-resistant enterococci (VRE) suggests that antimicrobial resistance is an inevitable evolutionary response to antimicrobial use. This highlights the tremendous need for antibiotics against new bacterial targets. Agents that target the integrity of bacterial membrane are relatively novel in the clinical armamentarium. Daptomycin, a lipopeptide is a classical example of membrane-bound antibiotic. Nature has also utilized this tactic. Antimicrobial peptides (AMPs), which are found in all kingdoms, function primarily by permeabilizing the bacterial membrane. AMPs have several advantages over existing antibiotics including a broad spectrum of activity, rapid bactericidal activity, no cross-resistance with the existing antibiotics and a low probability for developing resistance. Currently, a small number of peptides have been developed for clinical use but therapeutic applications are limited because of poor bioavailability and high manufacturing cost. However, their broad specificity, potent activity and lower probability for resistance have spurred the search for synthetic mimetics of antimicrobial peptides as membrane-active antibiotics. In this review, we will discuss the different classes of synthetic membrane-bound antibiotics published since 2004.

  2. Aerosol Optical Depth Over India

    Science.gov (United States)

    David, Liji Mary; Ravishankara, A. R.; Kodros, John K.; Venkataraman, Chandra; Sadavarte, Pankaj; Pierce, Jeffrey R.; Chaliyakunnel, Sreelekha; Millet, Dylan B.

    2018-04-01

    Tropospheric aerosol optical depth (AOD) over India was simulated by Goddard Earth Observing System (GEOS)-Chem, a global 3-D chemical-transport model, using SMOG (Speciated Multi-pOllutant Generator from Indian Institute of Technology Bombay) and GEOS-Chem (GC) (current inventories used in the GEOS-Chem model) inventories for 2012. The simulated AODs were 80% (SMOG) and 60% (GC) of those measured by the satellites (Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging SpectroRadiometer). There is no strong seasonal variation in AOD over India. The peak AOD values are observed/simulated during summer. The simulated AOD using SMOG inventory has particulate black and organic carbon AOD higher by a factor 5 and 3, respectively, compared to GC inventory. The model underpredicted coarse-mode AOD but agreed for fine-mode AOD with Aerosol Robotic Network data. It captured dust only over Western India, which is a desert, and not elsewhere, probably due to inaccurate dust transport and/or noninclusion of other dust sources. The calculated AOD, after dust correction, showed the general features in its observed spatial variation. Highest AOD values were observed over the Indo-Gangetic Plain followed by Central and Southern India with lowest values in Northern India. Transport of aerosols from Indo-Gangetic Plain and Central India into Eastern India, where emissions are low, is significant. The major contributors to total AOD over India are inorganic aerosol (41-64%), organic carbon (14-26%), and dust (7-32%). AOD over most regions of India is a factor of 5 or higher than over the United States.

  3. An experimental study of perovskite-structured mixed ionic- electronic conducting oxides and membranes

    Science.gov (United States)

    Zeng, Pingying

    In recent decades, ceramic membranes based on mixed ionic and electronic conducting (MIEC) perovskite-structured oxides have received many attentions for their applications for air separation, or as a membrane reactor for methane oxidation. While numerous perovskite oxide materials have been explored over the past two decades; there are hardly any materials with sufficient practical economic value and performance for large scale applications, which justifies continuing the search for new materials. The main purposes of this thesis study are: (1) develop several novel SrCoO3-delta based MIEC oxides, SrCoCo1-xMxO3-delta, based on which membranes exhibit excellent oxygen permeability; (2) investigate the significant effects of the species and concentration of the dopants M (metal ions with fixed valences) on the various properties of these membranes; (3) investigate the significant effects of sintering temperature on the microstructures and performance of oxygen permeation membranes; and (4) study the performance of oxygen permeation membranes as a membrane reactor for methane combustion. To stabilize the cubic phase structure of the SrCoO3-delta oxide, various amounts of scandium was doped into the B-site of SrCoO 3-delta to form a series of new perovskite oxides, SrScxCoCo 1-xO3-delta (SSCx, x = 0-0.7). The significant effects of scandium-doping concentration on the phase structure, electrical conductivity, sintering performance, thermal and structural stability, cathode performance, and oxygen permeation performance of the SSCx membranes, were systematically studied. Also for a more in-depth understanding, the rate determination steps for the oxygen transport process through the membranes were clarified by theoretical and experimental investigation. It was found that only a minor amount of scandium (5 mol%) doping into the B-site of SrCoO3-delta can effectively stabilize the cubic phase structure, and thus significantly improve the electrical conductivity and

  4. 3. International conference on catalysis in membrane reactors

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    The 3. International Conference on Catalysis in Membrane Reactors, Copenhagen, Denmark, is a continuation of the previous conferences held in Villeurbanne 1994 and Moscow 1996 and will deal with the rapid developments taking place within membranes with emphasis on membrane catalysis. The approx. 80 contributions in form of plenary lectures and posters discuss hydrogen production, methane reforming into syngas, selectivity and specificity of various membranes etc. The conference is organised by the Danish Catalytic Society under the Danish Society for Chemical Engineering. (EG)

  5. MEMBRANE BIOREACTOR FOR TREATMENT OF RECALCITRANT WASTEWATERS

    Directory of Open Access Journals (Sweden)

    Suprihatin Suprihatin

    2012-02-01

    Full Text Available The low biodegradable wastewaters remain a challenge in wastewater treatment technology. The performance of membrane bioreactor systems with submerged hollow fiber micro- and ultrafiltration membrane modules were examined for purifying recalcitrant wastewaters of leachate of a municipal solid waste open dumping site and effluent of pulp and paper mill. The use of MF and UF membrane bioreactor systems showed an efficient treatment for both types wastewaters with COD reduction of 80-90%. The membrane process achieved the desirable effects of maintaining reasonably high biomass concentration and long sludge retention time, while producing a colloid or particle free effluent. For pulp and paper mill effluent a specific sludge production of 0.11 kg MLSS/kg COD removed was achieved. A permeate flux of about 5 L/m²h could be achieved with the submerged microfiltration membrane. Experiments using ultrafiltration membrane produced relatively low permeate fluxes of 2 L/m²h. By applying periodical backwash, the flux could be improved significantly. It was indicated that the particle or colloid deposition on membrane surface was suppressed by backwash, but reformation of deposit was not effectively be prevented by shear-rate effect of aeration. Particle and colloid started to accumulate soon after backwash. Construction of membrane module and operation mode played a critical role in achieving the effectiveness of aeration in minimizing deposit formation on the membrane surface.

  6. Recent advances in membrane materials: introductory remarks

    International Nuclear Information System (INIS)

    Ayral, A.

    2007-01-01

    A lot of separation operations are currently performed using membranes both for production processes and for environmental applications. The main part of the used membranes are organic membranes but for specific conditions of utilization inorganic or organic-inorganic membranes have been also developed. Among the applications for gas separation, some examples are the removal of hydrogen from ammonia synthesis gas, the removal of carbon dioxide from natural gas and air separation. Environmental considerations like massive scale air and water pollution and also the gradual rarefaction of fossil energy resources gave rise to the concept of sustainable growth and to related strategies like process intensification, the reuse of water and solvents at their point of use, hydrogen as energy vector (requiring H 2 production...)..Membranes will have a key part to play in the new technologies associated with these strategies. Intensive efforts of research and development are now engaged everywhere in the world to develop high performance membranes for those emerging applications. Membrane science is a multidisciplinary scientific and technological domain covering mainly materials science, physical chemistry, chemical engineering, modeling. This issue (Annales de chimie - Science des materiaux, 2007 Vol.32 N.2) provides a wide review of recent advances in membrane materials. It is based on the contributions of experts in different fields of membrane materials (organic, organic-inorganic hybrid, composite, carbon, metallic, ceramic; dense, porous, surface modified materials). (O.M.)

  7. Is visual short-term memory depthful?

    Science.gov (United States)

    Reeves, Adam; Lei, Quan

    2014-03-01

    Does visual short-term memory (VSTM) depend on depth, as it might be if information was stored in more than one depth layer? Depth is critical in natural viewing and might be expected to affect retention, but whether this is so is currently unknown. Cued partial reports of letter arrays (Sperling, 1960) were measured up to 700 ms after display termination. Adding stereoscopic depth hardly affected VSTM capacity or decay inferred from total errors. The pattern of transposition errors (letters reported from an uncued row) was almost independent of depth and cue delay. We conclude that VSTM is effectively two-dimensional. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Characterising antimicrobial protein-membrane complexes

    International Nuclear Information System (INIS)

    Xun, Gloria; Dingley, Andrew; Tremouilhac, Pierre

    2009-01-01

    Full text: Antimicrobial proteins (AMPs) are host defence molecules that protect organisms from microbial infection. A number of hypotheses for AMP activity have been proposed which involve protein membrane interactions. However, there is a paucity of information describing AMP-membrane complexes in detail. The aim of this project is to characterise the interactions of amoebapore-A (APA-1) with membrane models using primarily solution-state NMR spectroscopy. APA-1 is an AMP which is regulated by a pH-dependent dimerisation event. Based on the atomic resolution solution structure of monomeric APA-1, it is proposed that this dimerisation is a prerequisite for ring-like hexameric pore formation. Due to the cytotoxicity of APA-1, we have developed a cell-free system to produce this protein. To facilitate our studies, we have adapted the cell-free system to isotope label APA-1. 13 C /15 N -enriched APA-1 sample was achieved and we have begun characterising APA-1 dimerisation and membrane interactions using NMR spectroscopy and other biochemical/biophysical methods. Neutron reflectometry is a surface-sensitive technique and therefore represents an ideal technique to probe how APA-1 interacts with membranes at the molecular level under different physiological conditions. Using Platypus, the pH-induced APA-1-membrane interactions should be detectable as an increase of the amount of protein adsorbed at the membrane surface and changes in the membrane properties. Specifically, detailed information of the structure and dimensions of the protein-membrane complex, the position and amount of the protein in the membrane, and the perturbation of the membrane phospholipids on protein incorporation can be extracted from the neutron reflectometry measurement. Such information will enable critical assessment of current proposed mechanisms of AMP activity in bacterial membranes and complement our NMR studies

  9. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  10. Premature rupture of membranes

    Science.gov (United States)

    ... gov/ency/patientinstructions/000512.htm Premature rupture of membranes To use the sharing features on this page, ... water that surrounds your baby in the womb. Membranes or layers of tissue hold in this fluid. ...

  11. Oxygen transport membrane

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  12. Membrane with integrated spacer

    NARCIS (Netherlands)

    Balster, J.H.; Stamatialis, Dimitrios; Wessling, Matthias

    2010-01-01

    Many membrane processes are severely influenced by concentration polarisation. Turbulence promoting spacers placed in between the membranes can reduce the diffusional resistance of concentration polarisation by inducing additional mixing. Electrodialysis (ED) used for desalination suffers from

  13. Gel layer formation on membranes in Membrane Bioreactors

    NARCIS (Netherlands)

    Van den Brink, P.F.H.

    2014-01-01

    The widespread application of membrane bioreactors (MBRs) for municipal wastewater treatment is hampered by membrane fouling. Fouling increases energy demand, reduces process performance and creates the need for more frequent (chemical) membrane cleaning or replacement. Membrane fouling in MBRs is

  14. Smart membranes for monitoring membrane based desalination processes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem; Karam, Ayman M.

    2017-01-01

    Various examples are related to smart membranes for monitoring membrane based process such as, e.g., membrane distillation processes. In one example, a membrane, includes a porous surface and a plurality of sensors (e.g., temperature, flow and

  15. Latent stereopsis for motion in depth in strabismic amblyopia.

    Science.gov (United States)

    Hess, Robert F; Mansouri, Behzad; Thompson, Benjamin; Gheorghiu, Elena

    2009-10-01

    To investigate the residual stereo function of a group of 15 patients with strabismic amblyopia, by using motion-in-depth stimuli that allow discrimination of contributions from local disparity as opposed to those from local velocity mechanisms as a function of the rate of depth change. The stereo performance (percentage correct) was measured as a function of the rate of depth change for dynamic random dot stimuli that were either temporally correlated or uncorrelated. Residual stereoscopic function was demonstrated for motion in depth based on local disparity information in 2 of the 15 observers with strabismic amblyopia. The use of a neutral-density (ND) filter in front of the fixing eye enhanced motion-in-depth performance in four subjects randomly selected from the group that originally displayed only chance performance. This finding was true across temporal rate and for correlated and uncorrelated stimuli, suggesting that it was disparity based. The opposite occurred in a group of normal subjects. In a separate experiment, the hypothesis was that the beneficial effect of the ND filter is due to its contrast and/or mean luminance-reducing effects rather than any interocular time delay that it may introduce and that it is specific to motion-in-depth performance, as similar improvements were not found for static stereopsis. A small proportion of observers with strabismic amblyopia exhibit residual performance for motion in depth, and it is disparity based. Furthermore, some observers with strabismic amblyopia who do not display any significant stereo performance for motion in depth under normal binocular viewing may display above-chance stereo performance if the degree of interocular suppression is reduced. The authors term this phenomenon latent stereopsis.

  16. Model cell membranes

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Nylander, Tommy; Cardenas Gomez, Marite

    2014-01-01

    The high complexity of biological membranes has motivated the development and application of a wide range of model membrane systems to study biochemical and biophysical aspects of membranes in situ under well defined conditions. The aim is to provide fundamental understanding of processes control...

  17. Idiopathic epiretinal membrane

    NARCIS (Netherlands)

    Bu, Shao-Chong; Kuijer, Roelof; Li, Xiao-Rong; Hooymans, Johanna M M; Los, Leonoor I

    2014-01-01

    Background: Idiopathic epiretinal membrane (iERM) is a fibrocellular membrane that proliferates on the inner surface of the retina at the macular area. Membrane contraction is an important sight-threatening event and is due to fibrotic remodeling. Methods: Analysis of the current literature

  18. Meniscus Membranes For Separation

    Science.gov (United States)

    Dye, Robert C.; Jorgensen, Betty; Pesiri, David R.

    2005-09-20

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  19. Meniscus membranes for separations

    Science.gov (United States)

    Dye, Robert C [Irvine, CA; Jorgensen, Betty [Jemez Springs, NM; Pesiri, David R [Aliso Viejo, CA

    2004-01-27

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  20. Subring Depth, Frobenius Extensions, and Towers

    Directory of Open Access Journals (Sweden)

    Lars Kadison

    2012-01-01

    Full Text Available The minimum depth d(B,A of a subring B⊆A introduced in the work of Boltje, Danz and Külshammer (2011 is studied and compared with the tower depth of a Frobenius extension. We show that d(B,A < ∞ if A is a finite-dimensional algebra and Be has finite representation type. Some conditions in terms of depth and QF property are given that ensure that the modular function of a Hopf algebra restricts to the modular function of a Hopf subalgebra. If A⊇B is a QF extension, minimum left and right even subring depths are shown to coincide. If A⊇B is a Frobenius extension with surjective Frobenius, homomorphism, its subring depth is shown to coincide with its tower depth. Formulas for the ring, module, Frobenius and Temperley-Lieb structures are noted for the tower over a Frobenius extension in its realization as tensor powers. A depth 3 QF extension is embedded in a depth 2 QF extension; in turn certain depth n extensions embed in depth 3 extensions if they are Frobenius extensions or other special ring extensions with ring structures on their relative Hochschild bar resolution groups.

  1. Membrane barriers for radon gas flow restrictions

    International Nuclear Information System (INIS)

    Archibald, J.F.

    1984-08-01

    Research was performed to assess the feasibility of barrier membrane substances, for use within mining or associated high risk environments, in restricting the diffusion transport of radon gas quantities. Specific tests were conducted to determine permeability parameters of a variety of membrane materials with reference to radon flow capabilities. Tests were conducted both within laboratory and in-situ emanation environments where concentrations and diffusion flows of radon gas were known to exist. Equilibrium radon gas concentrations were monitored in initially radon-free chambers adjacent to gas sources, but separated by specified membrane substances. Membrane barrier effectiveness was demonstrated to result in reduced emanation concentrations of radon gas within the sampling chamber atmosphere. Minimum gas concentrations were evidenced where the barrier membrane material was shown to exhibit lowest radon permeability characteristics

  2. Vitreous membranes used in the biogas purification

    International Nuclear Information System (INIS)

    Ortega Viera, L.; Rodriguez Munoz, S.; Fernandez Santana, E.; Martines Ramirez, Y.; Crespo Artigas, A.; Viera Gallardo, Y.

    2016-01-01

    In the present work 10 vitreous membranes with different masses of zinc oxide (ZnO(s)) and particle diameters charcoal (DPC) are used in the purification of biogas. The porosity and tortuosity of the membranes is obtained, showing the variation with respect to the composition thereof. From these structural features specific flow of H 2 S(g) is obtained which is transferred using the Fick's diffusion equation in the membranes and its value increases with increasing mass of ZnO(s). By X-ray diffraction membrane made with 3.16 g of ZnO(s) forming zinc sulfide it is shown, so we can say that the removal of H 2 S(g) occurs by a process of absorption with chemical reaction in the membranes. (Author)

  3. Membrane tethering complexes in the endosomal system

    Directory of Open Access Journals (Sweden)

    Anne eSpang

    2016-05-01

    Full Text Available Vesicles that are generated by endocytic events at the plasma membrane are destined to early endosomes. A prerequisite for proper fusion is the tethering of two membrane entities. Tethering of vesicles to early endosomes is mediated by the CORVET complex, while fusion of late endosomes with lysosomes depends on the HOPS complex. Recycling through the TGN and to the plasma membrane is facilitated by the GARP and EARP complexes, respectively. However, there are other tethering functions in the endosomal system as there are multiple pathways through which proteins can be delivered from endosomes to either the TGN or the plasma membrane. Furthermore, complexes that may be part of novel tethering complexes have been recently identified. Thus it is likely that more tethering factors exist. In this review, I will provide an overview of different tethering complexes of the endosomal system and discuss how they may provide specificity in membrane traffic.

  4. Pilot demonstration of energy-efficient membrane bioreactor (MBR) using reciprocating submerged membrane.

    Science.gov (United States)

    Ho, Jaeho; Smith, Shaleena; Patamasank, Jaren; Tontcheva, Petia; Kim, Gyu Dong; Roh, Hyung Keun

    2015-03-01

    Membrane bioreactor (MBR) is becoming popular for advanced wastewater treatment and water reuse. Air scouring to "shake" the membrane fibers is most suitable and applicable to maintain filtration without severe and rapidfouling. However, membrane fouling mitigating technologies are energy intensive. The goal of this research is to develop an alternative energy-saving MBR system to reduce energy consumption; a revolutionary system that will directly compete with air scouring technologies currently in the membrane water reuse market. The innovative MBR system, called reciprocation MBR (rMBR), prevents membrane fouling without the use of air scouring blowers. The mechanism featured is a mechanical reciprocating membrane frame that uses inertia to prevent fouling. Direct strong agitation of the fiber is also beneficial for the constant removal of solids built up on the membrane surface. The rMBR pilot consumes less energy than conventional coarse air scouring MBR systems. Specific energy consumption for membrane reciprocation for the pilot rMBR system was 0.072 kWh/m3 permeate produced at 40 LMH, which is 75% less than the conventional air scouring in an MBR system (0.29 kWh/m3). Reciprocation of the hollow-fiber membrane can overcome the hydrodynamic limitations of air scouring or cross-flow membrane systems with less energy consumption and/or higher energy efficiency.

  5. Separation membrane development

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.W. [Savannah River Technology Center, Aiken, SC (United States)

    1998-08-01

    A ceramic membrane has been developed to separate hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to separate hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.

  6. Post-Fusion Membrane Reorganization.

    Science.gov (United States)

    1993-01-27

    diphosphoglycerate , and NEM (a crosslinking agent), and ethanol treatments all had reproducible and very specific effects on the kinetic phases and the fusion product...actually, at the ultrastructure level , a double membrane multiply perforated with fusion sites (or pores). Also, because the heat treatment was within...relationships. Moreover. 2.3- Diphosphoglycerate (2-3-DPG). a naturally occuring metabolite which is known to have a regulatory role in spectrin-cytoskeletal

  7. Coding of Depth Images for 3DTV

    DEFF Research Database (Denmark)

    Zamarin, Marco; Forchhammer, Søren

    In this short paper a brief overview of the topic of coding and compression of depth images for multi-view image and video coding is provided. Depth images represent a convenient way to describe distances in the 3D scene, useful for 3D video processing purposes. Standard approaches...... for the compression of depth images are described and compared against some recent specialized algorithms able to achieve higher compression performances. Future research directions close the paper....

  8. A biodegradable vascularizing membrane: a feasibility study.

    Science.gov (United States)

    Kaushiva, Anchal; Turzhitsky, Vladimir M; Darmoc, Marissa; Backman, Vadim; Ameer, Guillermo A

    2007-09-01

    Regenerative medicine and in vivo biosensor applications require the formation of mature vascular networks for long-term success. This study investigated whether biodegradable porous membranes could induce the formation of a vascularized fibrous capsule and, if so, the effect of degradation kinetics on neovascularization. Poly(l-lactic acid) (PLLA) and poly(dl-lactic-co-glycolic) acid (PLGA) membranes were created by a solvent casting/salt leaching method. Specifically, PLLA, PLGA 75:25 and PLGA 50:50 polymers were used to vary degradation kinetics. The membranes were designed to have an average 60mum pore diameter, as this pore size has been shown to be optimal for inducing blood vessel formation around nondegradable polymer materials. Membrane samples were imaged by scanning electron microscopy at several time points during in vitro degradation to assess any changes in pore structure. The in vivo performance of the membranes was assessed in Sprague-Dawley rats by measuring vascularization within the fibrous capsule that forms adjacent to implants. The vascular density within 100microm of the membranes was compared with that seen in normal tissue, and to that surrounding the commercially available vascularizing membrane TheraCyte. The hemoglobin content of tissue containing the membranes was measured by four-dimensional elastic light scattering as a novel method to assess tissue perfusion. Results from this study show that slow-degrading membranes induce greater amounts of neovascularization and a thinner fibrous capsule relative to fast degrading membranes. These results may be due both to an initially increased number of macrophages surrounding the slower degrading membranes and to the maintenance of their initial pore structure.

  9. Microporous silica membranes

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Yue, Yuanzheng

    2012-01-01

    Hydrothermal stability is a crucial factor for the application of microporous silica-based membranes in industrial processes. Indeed, it is well established that steam exposure may cause densification and defect formation in microporous silica membranes, which are detrimental to both membrane...... permeability and selectivity. Numerous previous studies show that microporous transition metal doped-silica membranes are hydrothermally more stable than pure silica membranes, but less permeable. Here we present a quantitative study on the impact of type and concentration of transition metal ions...... on the microporous structure, stability and permeability of amorphous silica-based membranes, providing information on how to design chemical compositions and synthetic paths for the fabrication of silica-based membranes with a well accessible and highly stabile microporous structure....

  10. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become

  11. Depth Perception In Remote Stereoscopic Viewing Systems

    Science.gov (United States)

    Diner, Daniel B.; Von Sydow, Marika

    1989-01-01

    Report describes theoretical and experimental studies of perception of depth by human operators through stereoscopic video systems. Purpose of such studies to optimize dual-camera configurations used to view workspaces of remote manipulators at distances of 1 to 3 m from cameras. According to analysis, static stereoscopic depth distortion decreased, without decreasing stereoscopitc depth resolution, by increasing camera-to-object and intercamera distances and camera focal length. Further predicts dynamic stereoscopic depth distortion reduced by rotating cameras around center of circle passing through point of convergence of viewing axes and first nodal points of two camera lenses.

  12. ACCURACY ANALYSIS OF KINECT DEPTH DATA

    Directory of Open Access Journals (Sweden)

    K. Khoshelham

    2012-09-01

    Full Text Available This paper presents an investigation of the geometric quality of depth data obtained by the Kinect sensor. Based on the mathematical model of depth measurement by the sensor a theoretical error analysis is presented, which provides an insight into the factors influencing the accuracy of the data. Experimental results show that the random error of depth measurement increases with increasing distance to the sensor, and ranges from a few millimetres up to about 4 cm at the maximum range of the sensor. The accuracy of the data is also found to be influenced by the low resolution of the depth measurements.

  13. Meninges: from protective membrane to stem cell niche

    OpenAIRE

    Decimo, Ilaria; Fumagalli, Guido; Berton, Valeria; Krampera, Mauro; Bifari, Francesco

    2012-01-01

    Meninges are a three tissue membrane primarily known as coverings of the brain. More in depth studies on meningeal function and ultrastructure have recently changed the view of meninges as a merely protective membrane. Accurate evaluation of the anatomical distribution in the CNS reveals that meninges largely penetrate inside the neural tissue. Meninges enter the CNS by projecting between structures, in the stroma of choroid plexus and form the perivascular space (Virchow-Robin) of every pare...

  14. An Exploration of the Needling Depth in Acupuncture: The Safe Needling Depth and the Needling Depth of Clinical Efficacy

    Directory of Open Access Journals (Sweden)

    Jaung-Geng Lin

    2013-01-01

    Full Text Available Objective. To explore the existing scientific information regarding safe needling depth of acupuncture points and the needling depth of clinical efficacy. Methods. We searched the PubMed, EMBASE, Cochrane, Allied and Complementary Medicine (AMED, The National Center for Complementary and Alternative Medicine (NCCAM, and China National Knowledge Infrastructure (CNKI databases to identify relevant monographs and related references from 1991 to 2013. Chinese journals and theses/dissertations were hand searched. Results. 47 studies were recruited and divided into 6 groups by measuring tools, that is, MRI, in vivo evaluation, CT, ultrasound, dissected specimen of cadavers, and another group with clinical efficacy. Each research was analyzed for study design, definition of safe depth, and factors that would affect the measured depths. Depths of clinical efficacy were discussed from the perspective of de-qi and other clinical observations. Conclusions. Great inconsistency in depth of each point measured from different subject groups and tools exists. The definition of safe depth should be established through standardization. There is also lack of researches to compare the clinical efficacy. A well-designed clinical trial selecting proper measuring tools to decide the actual and advisable needling depth for each point, to avoid adverse effects or complications and promote optimal clinical efficacy, is a top priority.

  15. Depth perception: the need to report ocean biogeochemical rates as functions of temperature, not depth.

    Science.gov (United States)

    Brewer, Peter G; Peltzer, Edward T

    2017-09-13

    For over 50 years, ocean scientists have oddly represented ocean oxygen consumption rates as a function of depth but not temperature in most biogeochemical models. This unique tradition or tactic inhibits useful discussion of climate change impacts, where specific and fundamental temperature-dependent terms are required. Tracer-based determinations of oxygen consumption rates in the deep sea are nearly universally reported as a function of depth in spite of their well-known microbial basis. In recent work, we have shown that a carefully determined profile of oxygen consumption rates in the Sargasso Sea can be well represented by a classical Arrhenius function with an activation energy of 86.5 kJ mol -1 , leading to a Q 10 of 3.63. This indicates that for 2°C warming, we will have a 29% increase in ocean oxygen consumption rates, and for 3°C warming, a 47% increase, potentially leading to large-scale ocean hypoxia should a sufficient amount of organic matter be available to microbes. Here, we show that the same principles apply to a worldwide collation of tracer-based oxygen consumption rate data and that some 95% of ocean oxygen consumption is driven by temperature, not depth, and thus will have a strong climate dependence. The Arrhenius/Eyring equations are no simple panacea and they require a non-equilibrium steady state to exist. Where transient events are in progress, this stricture is not obeyed and we show one such possible example.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'. © 2017 The Author(s).

  16. Depth perception: the need to report ocean biogeochemical rates as functions of temperature, not depth

    Science.gov (United States)

    Brewer, Peter G.; Peltzer, Edward T.

    2017-08-01

    For over 50 years, ocean scientists have oddly represented ocean oxygen consumption rates as a function of depth but not temperature in most biogeochemical models. This unique tradition or tactic inhibits useful discussion of climate change impacts, where specific and fundamental temperature-dependent terms are required. Tracer-based determinations of oxygen consumption rates in the deep sea are nearly universally reported as a function of depth in spite of their well-known microbial basis. In recent work, we have shown that a carefully determined profile of oxygen consumption rates in the Sargasso Sea can be well represented by a classical Arrhenius function with an activation energy of 86.5 kJ mol-1, leading to a Q10 of 3.63. This indicates that for 2°C warming, we will have a 29% increase in ocean oxygen consumption rates, and for 3°C warming, a 47% increase, potentially leading to large-scale ocean hypoxia should a sufficient amount of organic matter be available to microbes. Here, we show that the same principles apply to a worldwide collation of tracer-based oxygen consumption rate data and that some 95% of ocean oxygen consumption is driven by temperature, not depth, and thus will have a strong climate dependence. The Arrhenius/Eyring equations are no simple panacea and they require a non-equilibrium steady state to exist. Where transient events are in progress, this stricture is not obeyed and we show one such possible example. This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.

  17. Model of mouth-to-mouth transfer of bacterial lipoproteins through inner membrane LolC, periplasmic LolA, and outer membrane LolB

    OpenAIRE

    Okuda, Suguru; Tokuda, Hajime

    2009-01-01

    Outer membrane-specific lipoproteins in Escherichia coli are released from the inner membrane by an ATP-binding cassette transporter, the LolCDE complex, which causes the formation of a soluble complex with a periplasmic molecular chaperone, LolA. LolA then transports lipoproteins to the outer membrane where an outer membrane receptor, LolB, incorporates lipoproteins into the outer membrane. The molecular mechanisms underlying the Lol-dependent lipoprotein sorting have been clarified in detai...

  18. Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers

    KAUST Repository

    Chu, Shidong

    2010-11-01

    A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine (PSPC) phospholipid bilayers as paramagnetic moieties and the resulting enhancements of the longitudinal relaxation (T1) times of 31P nuclei on the surface of the bilayers were measured by a standard inversion recovery pulse sequence. The 31P NMR spin-lattice relaxation times decrease steadily as the DOXYL spin label moves closer to the surface as well as the concentration of the spin-labeled lipids increase. The enhanced relaxation vs. the position and concentration of spin-labels indicate that PRE induced by the DOXYL spin label are significant to determine longer distances over the whole range of the membrane depths. When these data were combined with estimated correlation times τc, the r-6-weighted, time-averaged distances between the spin-labels and the 31P nuclei on the membrane surface were estimated. The application of using this solid-state NMR PRE approach coupled with site-directed spin labeling (SDSL) may be a powerful method for measuring membrane protein immersion depth. © 2010 Elsevier Inc. All rights reserved.

  19. ROCK1-directed basement membrane positioning coordinates epithelial tissue polarity.

    Science.gov (United States)

    Daley, William P; Gervais, Elise M; Centanni, Samuel W; Gulfo, Kathryn M; Nelson, Deirdre A; Larsen, Melinda

    2012-01-01

    The basement membrane is crucial for epithelial tissue organization and function. However, the mechanisms by which basement membrane is restricted to the basal periphery of epithelial tissues and the basement membrane-mediated signals that regulate coordinated tissue organization are not well defined. Here, we report that Rho kinase (ROCK) controls coordinated tissue organization by restricting basement membrane to the epithelial basal periphery in developing mouse submandibular salivary glands, and that ROCK inhibition results in accumulation of ectopic basement membrane throughout the epithelial compartment. ROCK-regulated restriction of PAR-1b (MARK2) localization in the outer basal epithelial cell layer is required for basement membrane positioning at the tissue periphery. PAR-1b is specifically required for basement membrane deposition, as inhibition of PAR-1b kinase activity prevents basement membrane deposition and disrupts overall tissue organization, and suppression of PAR-1b together with ROCK inhibition prevents interior accumulations of basement membrane. Conversely, ectopic overexpression of wild-type PAR-1b results in ectopic interior basement membrane deposition. Significantly, culture of salivary epithelial cells on exogenous basement membrane rescues epithelial organization in the presence of ROCK1 or PAR-1b inhibition, and this basement membrane-mediated rescue requires functional integrin β1 to maintain epithelial cell-cell adhesions. Taken together, these studies indicate that ROCK1/PAR-1b-dependent regulation of basement membrane placement is required for the coordination of tissue polarity and the elaboration of tissue structure in the developing submandibular salivary gland.

  20. Edge-preserving Intra mode for efficient depth map coding based on H.264/AVC

    DEFF Research Database (Denmark)

    Zamarin, Marco; Forchhammer, Søren

    2014-01-01

    Depth-image-based-rendering (DIBR) algorithms for 3D video communication systems based on the “multi-view video plus depth” format are very sensitive to the accuracy of depth information. Specifically, edge regions in the depth data should be preserved in the coding/decoding process to ensure good...... view synthesis performance, which directly affects the overall system performance. This paper proposes a novel scheme for edge-aware Intra depth compression based on the H.264/AVC framework enabled on both Intra (I) and Inter (P) slices. The proposed scheme includes a new Intra mode specifically...

  1. Binding of Neurotransmitters to Lipid Membranes

    DEFF Research Database (Denmark)

    Peters, Günther H.J.; Werge, Mikkel; Elf-Lind, Maria Northved

    2014-01-01

    / acetylated g-aminobutyrate (GABAneu) with a dipalmitoylphosphatidylcholine (DPPC) bilayer. This study was motivated by recent research results that suggested that neural transmission may also be affected by nonspecific interactions of NTs with the lipid matrix of the synaptic membrane. Our results revealed...... backbone of the phospholipids. It is surprising that hydrophilic solutes can deeply penetrate into the membrane pointing to the fact that membrane affinity is governed by specific interactions. Our MD simulations identified the salt-bridge between the primary amine of NTs and the lipid phosphate group...

  2. Synthesis and characterization of Nafion/TiO2 nanocomposite membrane for proton exchange membrane fuel cell.

    Science.gov (United States)

    Kim, Tae Young; Cho, Sung Yong

    2011-08-01

    In this study, the syntheses and characterizations of Nafion/TiO2 membranes for a proton exchange membrane fuel cell (PEMFC) were investigated. Porous TiO2 powders were synthesized using the sol-gel method; with Nafion/TiO2 nanocomposite membranes prepared using the casting method. An X-ray diffraction analysis demonstrated that the synthesized TiO2 had an anatase structure. The specific surface areas of the TiO2 and Nafion/TiO2 nanocomposite membrane were found to be 115.97 and 33.91 m2/g using a nitrogen adsorption analyzer. The energy dispersive spectra analysis indicated that the TiO2 particles were uniformly distributed in the nanocomposite membrane. The membrane electrode assembly prepared from the Nafion/TiO2 nanocomposite membrane gave the best PEMFC performance compared to the Nafion/P-25 and Nafion membranes.

  3. Probing lipid membrane electrostatics

    Science.gov (United States)

    Yang, Yi

    The electrostatic properties of lipid bilayer membranes play a significant role in many biological processes. Atomic force microscopy (AFM) is highly sensitive to membrane surface potential in electrolyte solutions. With fully characterized probe tips, AFM can perform quantitative electrostatic analysis of lipid membranes. Electrostatic interactions between Silicon nitride probes and supported zwitterionic dioleoylphosphatidylcholine (DOPC) bilayer with a variable fraction of anionic dioleoylphosphatidylserine (DOPS) were measured by AFM. Classical Gouy-Chapman theory was used to model the membrane electrostatics. The nonlinear Poisson-Boltzmann equation was numerically solved with finite element method to provide the potential distribution around the AFM tips. Theoretical tip-sample electrostatic interactions were calculated with the surface integral of both Maxwell and osmotic stress tensors on tip surface. The measured forces were interpreted with theoretical forces and the resulting surface charge densities of the membrane surfaces were in quantitative agreement with the Gouy-Chapman-Stern model of membrane charge regulation. It was demonstrated that the AFM can quantitatively detect membrane surface potential at a separation of several screening lengths, and that the AFM probe only perturbs the membrane surface potential by external field created by the internai membrane dipole moment. The analysis yields a dipole moment of 1.5 Debye per lipid with a dipole potential of +275 mV for supported DOPC membranes. This new ability to quantitatively measure the membrane dipole density in a noninvasive manner will be useful in identifying the biological effects of the dipole potential. Finally, heterogeneous model membranes were studied with fluid electric force microscopy (FEFM). Electrostatic mapping was demonstrated with 50 nm resolution. The capabilities of quantitative electrostatic measurement and lateral charge density mapping make AFM a unique and powerful

  4. Emulsification using microporous membranes

    Directory of Open Access Journals (Sweden)

    Goran T. Vladisavljević

    2011-10-01

    Full Text Available Membrane emulsification is a process of injecting a pure dispersed phase or pre-emulsion through a microporous membrane into the continuous phase. As a result of the immiscibility of the two phases, droplets of the dispersed phase are formed at the outlets of membrane pores. The droplets formed in the process are removed from the membrane surface by applying cross-flow or stirring of the continuous phase or using a dynamic (rotating or vibrating membrane. The most commonly used membrane for emulsification is the Shirasu Porous Glass (SPG membrane, fabricated through spinodal decomposition in a melt consisting of Japanese volcanic ash (Shirasu, boric acid and calcium carbonate. Microsieve membranes are increasingly popular as an alternative to highly tortuous glass and ceramic membranes. Microsieves are usually fabricated from nickel by photolithography and electroplating or they can be manufactured from silicon nitride via Reactive Ion Etching (RIE. An advantage of microsieves compared to the SPG membrane is in much higher transmembrane fluxes and higher tolerance to fouling by the emulsion ingredients due to the existence of short, straight through pores. Unlike conventional emulsification devices such as high-pressure valve homogenisers and rotor-stator devices, membrane emulsification devices permit a precise control over the mean pore size over a wide range and during the process insignificant amount of energy is dissipated as heat. The drop size is primarily determined by the pore size, but it depends also on other parameters, such as membrane wettability, emulsion formulation, shear stress on the membrane surface, transmembrane pressure, etc.

  5. FATE OF REVERSE OSMOSIS (RO) MEMBRANES DURING OXIDATION BY DISINFECTANTS USED IN WATER TREATMENT: IMPACT ON MEMBRANE STRUCTURE AND PERFORMANCES

    KAUST Repository

    Maugin, Thomas

    2013-12-01

    Providing pretreatment prior RO filtration is essential to avoid biofouling and subsequent loss of membrane performances. Chlorine is known to degrade polymeric membrane, improving or reducing membrane efficiency depending on oxidation conditions. This study aimed to assess the impact of alternative disinfectant, NH2Cl, as well as secondary oxidants formed during chloramination of seawater, e.g. HOBr, HOI, or used in water treatment e.g. ClO2, O3, on membrane structure and performances. Permeability, total and specific rejection (Cl-, SO4 2-, Br-, Boron), FTIR profile, elemental composition were analyzed. Results showed that each oxidant seems to react differently with the membrane. HOCl, HOBr, ClO2 and O3 improved membrane permeability but decreased rejection in different extent. In comparison, chloramines resulted in identical trends but oxidized membrane very slowly. On the contrary, iodine improved membrane rejection e.g. boron, but decreased permeability. Reaction conducted with chlorine, bromine, iodine and chloramines resulted in the incorporation of halogen in the membrane structure. All oxidant except iodine were able to break amide bonds of the membrane structure in our condition. In addition, chloramine seemed to react with membrane differently, involving a potential addition of nitrogen. Chloramination of seawater amplified membrane performances evolutions due to generation of bromochloramine. Moreover, chloramines reacted both with NOM and membrane during oxidation in natural seawater, leading to additional rejection drop.

  6. Depth image enhancement using perceptual texture priors

    Science.gov (United States)

    Bang, Duhyeon; Shim, Hyunjung

    2015-03-01

    A depth camera is widely used in various applications because it provides a depth image of the scene in real time. However, due to the limited power consumption, the depth camera presents severe noises, incapable of providing the high quality 3D data. Although the smoothness prior is often employed to subside the depth noise, it discards the geometric details so to degrade the distance resolution and hinder achieving the realism in 3D contents. In this paper, we propose a perceptual-based depth image enhancement technique that automatically recovers the depth details of various textures, using a statistical framework inspired by human mechanism of perceiving surface details by texture priors. We construct the database composed of the high quality normals. Based on the recent studies in human visual perception (HVP), we select the pattern density as a primary feature to classify textures. Upon the classification results, we match and substitute the noisy input normals with high quality normals in the database. As a result, our method provides the high quality depth image preserving the surface details. We expect that our work is effective to enhance the details of depth image from 3D sensors and to provide a high-fidelity virtual reality experience.

  7. A new method for depth profiling

    International Nuclear Information System (INIS)

    Chittleborough, C.W.; Chaudhri, M.A.; Rouse, J.L.

    1978-01-01

    A simple method for obtaining depth profiles of concentrations has been developed for charged particle induced nuclear reactions which produce γ-rays or neutrons. This method is particularly suitable for non-resonant reactions but is also applicable to resonant reactions and can examine the concentration of the sought nuclide throughout the entire activation depth of the incoming particles in the matrix

  8. Observability-in-depth: An essential complement to the defense-in-depth safety strategy in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Favaro, Francesca M.; Saleh, Joseph H. [Georgia Institute of Technology, Atlanta (United States)

    2014-12-15

    Defense-in-depth is a fundamental safety principle for the design and operation of nuclear power plants. Despite its general appeal, defense-in-depth is not without its drawbacks, which include its potential for concealing the occurrence of hazardous states in a system, and more generally rendering the latter more opaque for its operators and managers, thus resulting in safety blind spots. This in turn translates into a shrinking of the time window available for operators to identify an unfolding hazardous condition or situation and intervene to abate it. To prevent this drawback from materializing, we propose propose in this work a novel safety principle termed 'observability-in-depth'. We characterize it as the set of provisions technical, operational, and organizational designed to enable the monitoring and identification of emerging hazardous conditions and accident pathogens in real-time and over different time-scales. Observability-in-depth also requires the monitoring of conditions of all safety barriers that implement defense-in-depth; and in so doing it supports sense making of identified hazardous conditions, and the understanding of potential accident sequences that might follow (how they can propagate). Observability-in-depth is thus an information-centric principle, and its importance in accident prevention is in the value of the information it provides and actions or safety interventions it spurs. We examine several 'event reports' from the U.S. Nuclear Regulatory Commission database, which illustrate specific instances of violation of the observability-in-depth safety principle and the consequences that followed (e.g., unmonitored releases and loss of containments). We also revisit the Three Mile Island accident in light of the proposed principle, and identify causes and consequences of the lack of observability-in-depth related to this accident sequence. We illustrate both the benefits of adopting the observability-in-depth

  9. Depth of origin of magma in eruptions.

    Science.gov (United States)

    Becerril, Laura; Galindo, Ines; Gudmundsson, Agust; Morales, Jose Maria

    2013-09-26

    Many volcanic hazard factors--such as the likelihood and duration of an eruption, the eruption style, and the probability of its triggering large landslides or caldera collapses--relate to the depth of the magma source. Yet, the magma source depths are commonly poorly known, even in frequently erupting volcanoes such as Hekla in Iceland and Etna in Italy. Here we show how the length-thickness ratios of feeder dykes can be used to estimate the depth to the source magma chamber. Using this method, accurately measured volcanic fissures/feeder-dykes in El Hierro (Canary Islands) indicate a source depth of 11-15 km, which coincides with the main cloud of earthquake foci surrounding the magma chamber associated with the 2011-2012 eruption of El Hierro. The method can be used on widely available GPS and InSAR data to calculate the depths to the source magma chambers of active volcanoes worldwide.

  10. Ion-conducting membranes

    Science.gov (United States)

    Masel, Richard I.; Sajjad, Syed Dawar; Gao, Yan; Liu, Zengcai; Chen, Qingmei

    2017-12-26

    An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x. R.sub.s is a positively charged cyclic amine group. R.sub.x is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-R.sub.x groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.

  11. Polymalic Acid Tritryptophan Copolymer Interacts with Lipid Membrane Resulting in Membrane Solubilization

    Directory of Open Access Journals (Sweden)

    Hui Ding

    2017-01-01

    Full Text Available Anionic polymers with membrane permeation functionalities are highly desirable for secure cytoplasmic drug delivery. We have developed tritryptophan containing copolymer (P/WWW of polymalic acid (PMLA that permeates membranes by a mechanism different from previously described PMLA copolymers of trileucine (P/LLL and leucine ethyl ester (P/LOEt that use the “barrel stave” and “carpet” mechanism, respectively. The novel mechanism leads to solubilization of membranes by forming copolymer “belts” around planar membrane “packages.” The formation of such packages is supported by results obtained from studies including size-exclusion chromatography, confocal microscopy, and fluorescence energy transfer. According to this “belt” mechanism, it is hypothesized that P/WWW first attaches to the membrane surface. Subsequently the hydrophobic tryptophan side chains translocate into the periphery and insert into the lipid bilayer thereby cutting the membrane into packages. The reaction is driven by the high affinity between the tryptophan residues and lipid side chains resulting in a stable configuration. The formation of the membrane packages requires physical agitation suggesting that the success of the translocation depends on the fluidity of the membrane. It is emphasized that the “belt” mechanism could specifically function in the recognition of abnormal cells with high membrane fluidity and in response to hyperthermia.

  12. Membrane processes in nuclear technologies

    International Nuclear Information System (INIS)

    Zakrzewska-Trznadel, G.

    2006-01-01

    to the pressure-driven processes, e.g. ultrafiltration and reverse osmosis, which were studied on a laboratory and pilot scale. Verification of the potential application of reverse osmosis on an industrial scale for treatment of liquid low- and intermediate-level radioactive wastes has been carried out with the installation particularly designed and constructed for the Department of Radioactive Waste Processing, Institute of Atomic Energy at Swierk. The thin-layer composite membranes made from a cross-linked aromatic polyamide of high retention of NaCl (99,4-99,7%) were applied in this process. It has been proved that a three-stage installation enables the radioactive waste of specific radioactivity below 10 5 Bq/dm 3 to be cleaned down to 10 Bq/dm 3 in permeate, with simultaneous 7-15-fold reduction of the activity in the concentrate. The results of own studies concerning the removal of selected radionuclides from model aqueous solutions and radioactive wastes with ultra-filtration enhanced by complexation and sorption were also presented in this work. In these cases, the mineral (ceramic) porous membranes made from a-alumina, titanium and zirconium oxides were applied. These membranes exhibited a high resistance against ionizing radiation, aggressive chemical environment and high temperatures. The high effectiveness of removal of the main components of liquid radioactive waste like 134 Cs, 137 Cs, 60 Co, 124 Sb, 85 Sr, 152 Eu and 154 Eu with a hybrid ultrafiltration/complexation process has been experimentally proved. The effects of this type of complexing agent, its concentration and pH of the processed solution on the complexation effectiveness have been studied. Efficacy of the method was tested with real radioactive wastes. The monograph performs results of the studies on membrane distillation which has been proposed by the author for processing of liquid radioactive wastes, and the analysis of its applicability for nuclear desalination and the production of

  13. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  14. Facile preparation of salt-tolerant anion-exchange membrane adsorber using hydrophobic membrane as substrate.

    Science.gov (United States)

    Fan, Jinxin; Luo, Jianquan; Chen, Xiangrong; Wan, Yinhua

    2017-03-24

    In this study, a polyvinylidene fluoride (PVDF) hydrophobic membrane with high mechanical property was used as substrate to prepare salt-tolerant anion-exchange (STAE) membrane adsorber. Effective hydrophilization and functionalization of PVDF membrane was realized via polydopamine (PDA) deposition, thus overcoming the drawbacks of hydrophobic substrates including poor water permeability, inert property as well as severe non-specific adsorption. The following polyallylamine (PAH) coupling was carried out at pH 10.0, where unprotonated amine groups on PAH chains were more prone to couple with PDA. This membrane adsorber could remain 75% of protein binding capacity when NaCl concentration increased from 0 to 150mM, while its protein binding capacity was independent of flow rate from 10 to 100 membrane volume (MV)/min due to its high mechanical strength (tensile strength: 43.58±2.30MPa). With 200mM NaCl addition at pH 7.5, high purity (above 99%) and high recovery (almost 100%) of Immunoglobulin G (IgG) were obtained when using the STAE membrane adsorber to separate IgG/human serum albumin (HSA) mixture, being similar to that without NaCl at pH 6.0 (both under the flow rate of 10-100MV/min). Finally, the reliable reusability was confirmed by five reuse cycles of protein binding and elution operations. In comparison with commercial membrane adsorber, the new membrane adsorber exhibited a better mechanical property, higher IgG polishing efficiency and reusability, while the protein binding capacity was lower due to less NH 2 density on the membrane. The outcome of this work not only offers a facile and effective approach to prepare membrane adsorbers based on hydrophobic membranes, but also demonstrates great potential of this new designed STAE membrane adsorbers for efficient monoclonal antibody (mAb) polishing. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Gas separation membranes

    Science.gov (United States)

    Schell, William J.

    1979-01-01

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

  16. Anion exchange membrane

    Science.gov (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  17. Photoresponsive nanostructured membranes

    KAUST Repository

    Madhavan, Poornima

    2016-07-26

    The perspective of adding stimuli-response to isoporous membranes stimulates the development of separation devices with pores, which would open or close under control of environment chemical composition, temperature or exposure to light. Changes in pH and temperature have been previously investigated. In this work, we demonstrate for the first time the preparation of photoresponsive isoporous membranes, applying self-assembly non-solvent induced phase separation to a new light responsive block copolymer. First, we optimized the membrane formation by using poly(styrene-b-anthracene methyl methacrylate-b-methylmethacrylate) (PS-b-PAnMMA-b-PMMA) copolymer, identifying the most suitable solvent, copolymer block length, and other parameters. The obtained final triblock copolymer membrane morphologies were characterized using atomic force and electron microscopy. The microscopic analysis reveals that the PS-b-PAnMMA-b-PMMA copolymer can form both lamellar and ordered hexagonal nanoporous structures on the membrane top layer in appropriate solvent compositions. The nanostructured membrane emits fluorescence due to the presence of the anthracene mid-block. On irradiation of light the PS-b-PAnMMA-b-PMMA copolymer membranes has an additional stimuli response. The anthracene group undergoes conformational changes by forming [4 + 4] cycloadducts and this alters the membrane\\'s water flux and solute retention. © 2016 The Royal Society of Chemistry.

  18. Tides on Europa: The membrane paradigm

    Science.gov (United States)

    Beuthe, Mikael

    2015-03-01

    Jupiter's moon Europa has a thin icy crust which is decoupled from the mantle by a subsurface ocean. The crust thus responds to tidal forcing as a deformed membrane, cold at the top and near melting point at the bottom. In this paper I develop the membrane theory of viscoelastic shells with depth-dependent rheology with the dual goal of predicting tidal tectonics and computing tidal dissipation. Two parameters characterize the tidal response of the membrane: the effective Poisson's ratio ν bar and the membrane spring constant Λ, the latter being proportional to the crust thickness and effective shear modulus. I solve membrane theory in terms of tidal Love numbers, for which I derive analytical formulas depending on Λ, ν bar , the ocean-to-bulk density ratio and the number k2∘ representing the influence of the deep interior. Membrane formulas predict h2 and k2 with an accuracy of a few tenths of percent if the crust thickness is less than one hundred kilometers, whereas the error on l2 is a few percents. Benchmarking with the thick-shell software SatStress leads to the discovery of an error in the original, uncorrected version of the code that changes stress components by up to 40%. Regarding tectonics, I show that different stress-free states account for the conflicting predictions of thin and thick shell models about the magnitude of tensile stresses due to nonsynchronous rotation. Regarding dissipation, I prove that tidal heating in the crust is proportional to Im (Λ) and that it is equal to the global heat flow (proportional to Im (k2)) minus the core-mantle heat flow (proportional to Im (k2∘)). As an illustration, I compute the equilibrium thickness of a convecting crust. More generally, membrane formulas are useful in any application involving tidal Love numbers such as crust thickness estimates, despinning tectonics or true polar wander.

  19. Scene depth estimation using a moving camera

    International Nuclear Information System (INIS)

    Sune, Jean-Luc

    1995-01-01

    This thesis presents a solution of the depth-from-motion problem. The movement of the monocular observer is known. We have focused our research on a direct method which avoid the optical flow estimation required by classical approaches. The direct application of this method is not exploitable. We need to define a validity domain to extract the set of image points where it is possible to get a correct depth value. Also, we use a multi-scale approach to improve the derivatives estimation. The depth estimation for a given scale is obtained by the minimisation of an energy function established in the context of statistic regularization. A fusion operator, merging the various spatial and temporal scales, has been used to estimate the final depth map. A correction-prediction schema is used to integrate the temporal information from an image sequence. The predicted depth map is considered as an additional observation and integrated in the fusion process. At each time, an error depth map is associated to the estimated depth map. (author) [fr

  20. Hydrologic controls on equilibrium soil depths

    Science.gov (United States)

    Nicótina, L.; Tarboton, D. G.; Tesfa, T. K.; Rinaldo, A.

    2011-04-01

    This paper deals with modeling the mutual feedbacks between runoff production and geomorphological processes and attributes that lead to patterns of equilibrium soil depth. Our primary goal is an attempt to describe spatial patterns of soil depth resulting from long-term interactions between hydrologic forcings and soil production, erosion, and sediment transport processes under the framework of landscape dynamic equilibrium. Another goal is to set the premises for exploiting the role of soil depths in shaping the hydrologic response of a catchment. The relevance of the study stems from the massive improvement in hydrologic predictions for ungauged basins that would be achieved by using directly soil depths derived from geomorphic features remotely measured and objectively manipulated. Hydrological processes are here described by explicitly accounting for local soil depths and detailed catchment topography. Geomorphological processes are described by means of well-studied geomorphic transport laws. The modeling approach is applied to the semiarid Dry Creek Experimental Watershed, located near Boise, Idaho. Modeled soil depths are compared with field data obtained from an extensive survey of the catchment. Our results show the ability of the model to describe properly the mean soil depth and the broad features of the distribution of measured data. However, local comparisons show significant scatter whose origins are discussed.

  1. Hydrologic regulation of plant rooting depth.

    Science.gov (United States)

    Fan, Ying; Miguez-Macho, Gonzalo; Jobbágy, Esteban G; Jackson, Robert B; Otero-Casal, Carlos

    2017-10-03

    Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observations of >1,000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients. Results reveal strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow, avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to the groundwater capillary fringe. This framework explains the contrasting rooting depths observed under the same climate for the same species but at distinct topographic positions. We assess the global significance of these hydrologic mechanisms by estimating root water-uptake depths using an inverse model, based on observed productivity and atmosphere, at 30″ (∼1-km) global grids to capture the topography critical to soil hydrology. The resulting patterns of plant rooting depth bear a strong topographic and hydrologic signature at landscape to global scales. They underscore a fundamental plant-water feedback pathway that may be critical to understanding plant-mediated global change.

  2. Hydrologic regulation of plant rooting depth

    Science.gov (United States)

    Fan, Ying; Miguez-Macho, Gonzalo; Jobbágy, Esteban G.; Jackson, Robert B.; Otero-Casal, Carlos

    2017-10-01

    Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observations of >1,000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients. Results reveal strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow, avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to the groundwater capillary fringe. This framework explains the contrasting rooting depths observed under the same climate for the same species but at distinct topographic positions. We assess the global significance of these hydrologic mechanisms by estimating root water-uptake depths using an inverse model, based on observed productivity and atmosphere, at 30″ (˜1-km) global grids to capture the topography critical to soil hydrology. The resulting patterns of plant rooting depth bear a strong topographic and hydrologic signature at landscape to global scales. They underscore a fundamental plant-water feedback pathway that may be critical to understanding plant-mediated global change.

  3. Human action recognition with depth cameras

    CERN Document Server

    Wang, Jiang; Wu, Ying

    2014-01-01

    Action recognition technology has many real-world applications in human-computer interaction, surveillance, video retrieval, retirement home monitoring, and robotics. The commoditization of depth sensors has also opened up further applications that were not feasible before. This text focuses on feature representation and machine learning algorithms for action recognition from depth sensors. After presenting a comprehensive overview of the state of the art, the authors then provide in-depth descriptions of their recently developed feature representations and machine learning techniques, includi

  4. Environment-sensitive ion-track membranes

    International Nuclear Information System (INIS)

    Yoshida, Masaru

    1996-01-01

    Development of an environment-sensitive porous membrane from ion-track membranes may realize by combining the techniques of ion beam radiation and those of molecular designing and synthesis for intelligent materials. Now, the development of such membrane is progressing with an aim at selecting some specific substances and accurately control its pore size in response to any small environmental stimulus such as temperature change. The authors have been studying the molecular design, synthesis and functional expression of intelligent materials, which are called here as environment-sensitive gels. In this report, the outlines of the apparatus for the production of such porous membrane was described. An organic polymer membrane was irradiated with an ion beam and followed by chemical etching to make ion track pores. Scanning electron microscopic observation for the cross section of the membrane showed that the pore shape varies greatly depending on the ion nuclide used. The characteristics of newly produced porous membranes consisting of CR-30/A-ProDMe and polyethylene-telephtharate were investigated in respect of pore size change responding to temperature. These studies of design, synthesis and functions of such gels would enable to substitute artificial materials for the functions of human sensors. (M.N.). 54 refs

  5. Cell Membrane Transport Mechanisms: Ion Channels and Electrical Properties of Cell Membranes.

    Science.gov (United States)

    Kulbacka, Julita; Choromańska, Anna; Rossowska, Joanna; Weżgowiec, Joanna; Saczko, Jolanta; Rols, Marie-Pierre

    2017-01-01

    Cellular life strongly depends on the membrane ability to precisely control exchange of solutes between the internal and external (environmental) compartments. This barrier regulates which types of solutes can enter and leave the cell. Transmembrane transport involves complex mechanisms responsible for passive and active carriage of ions and small- and medium-size molecules. Transport mechanisms existing in the biological membranes highly determine proper cellular functions and contribute to drug transport. The present chapter deals with features and electrical properties of the cell membrane and addresses the questions how the cell membrane accomplishes transport functions and how transmembrane transport can be affected. Since dysfunctions of plasma membrane transporters very often are the cause of human diseases, we also report how specific transport mechanisms can be modulated or inhibited in order to enhance the therapeutic effect.

  6. The actin homologue MreB organizes the bacterial cell membrane.

    Science.gov (United States)

    Strahl, Henrik; Bürmann, Frank; Hamoen, Leendert W

    2014-03-07

    The eukaryotic cortical actin cytoskeleton creates specific lipid domains, including lipid rafts, which determine the distribution of many membrane proteins. Here we show that the bacterial actin homologue MreB displays a comparable activity. MreB forms membrane-associated filaments that coordinate bacterial cell wall synthesis. We noticed that the MreB cytoskeleton influences fluorescent staining of the cytoplasmic membrane. Detailed analyses combining an array of mutants, using specific lipid staining techniques and spectroscopic methods, revealed that MreB filaments create specific membrane regions with increased fluidity (RIFs). Interference with these fluid lipid domains (RIFs) perturbs overall lipid homeostasis and affects membrane protein localization. The influence of MreB on membrane organization and fluidity may explain why the active movement of MreB stimulates membrane protein diffusion. These novel MreB activities add additional complexity to bacterial cell membrane organization and have implications for many membrane-associated processes.

  7. Monocular depth effects on perceptual fading.

    Science.gov (United States)

    Hsu, Li-Chuan; Kramer, Peter; Yeh, Su-Ling

    2010-08-06

    After prolonged viewing, a static target among moving non-targets is perceived to repeatedly disappear and reappear. An uncrossed stereoscopic disparity of the target facilitates this Motion-Induced Blindness (MIB). Here we test whether monocular depth cues can affect MIB too, and whether they can also affect perceptual fading in static displays. Experiment 1 reveals an effect of interposition: more MIB when the target appears partially covered by, than when it appears to cover, its surroundings. Experiment 2 shows that the effect is indeed due to interposition and not to the target's contours. Experiment 3 induces depth with the watercolor illusion and replicates Experiment 1. Experiments 4 and 5 replicate Experiments 1 and 3 without the use of motion. Since almost any stimulus contains a monocular depth cue, we conclude that perceived depth affects perceptual fading in almost any stimulus, whether dynamic or static. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. Depth to Bedrock: Isopach of Unconsolidated Materials

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This vector dataset gives the approximate depth to bedrock (in feet) from Iowa's current land surface. This 50 foot isopach data was derived from the Digital...

  9. FINANCIAL DEPTH AND FINANCIAL ACCESS IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Sigit Setiawan

    2015-05-01

    Full Text Available This study is intended to analyze the current levels of financial depth and financial access in Indonesia and to analyze the factors affecting them. The analysis method used was a combination of descriptive quantitative, benchmarking, and literature reviews. The conclusion is that the financial depth in Indonesia has not shown a satisfactory level since it was the lowest, or the second lowest ranked country among the sampled countries. Meanwhile, the financial access in Indonesia is relatively better than its financial depth, especially for financial markets, in which Indonesia ranks in the lower average group. From literature reviews, it can be inferred that the main factor driving the poor financial depth in Indonesia is non-competitiveness of the institutions; whereas the driving force of poor financial access in Indonesia are geographical constraints, poverty, a high income gap, and a less than effective national financial development policy.

  10. Sputtering as a means of depth profiling

    International Nuclear Information System (INIS)

    Whitton, J.L.

    1978-01-01

    Probably the most common technique for determination of depth profiles by sputtering is that of secondary ion mass spectrometry. Many problems occur in the important step of converting the time (of sputtering) scale to a depth scale and these problems arise before the secondary ions are ejected. An attempt is made to present a comprehensive list of the effects that should be taken into consideration in the use of sputtering as a means of depth profiling. The various parameters liable to affect the depth profile measurements are listed in four sections: beam conditions; target conditions; experimental environment; and beam-target interactions. The effects are discussed and where interplay occurs, cross-reference is made and examples are provided where possible. (B.R.H.)

  11. Rand Corporation Mean Monthly Global Snow Depth

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — All available monthly snow depth climatologies were integrated by the Rand Corporation, in the early 1980s, into one global (excluding Africa and South America)...

  12. The Beryllium 7 Depth Distribution Study

    International Nuclear Information System (INIS)

    Jalal Sharib; Zainudin Othman; Dainee Nor Fardzila Ahmad Tugi

    2014-01-01

    The aim of this paper is to study the evolution of 7Be depth distribution in a soil profile. The soil samples have been collected by using plastic core in bare area in Bangi, Malaysia. Each of the soil core samples has been sectioned into 2 mm increments to a depth of 4 cm and the samples are subsequently oven dried at 45°C and gently disaggregated. The sample is passed through a < 2 mm sieve and packed into plastic pot for 7Be analysis using gamma spectrometry with a 24 hour count time. From the findings, show the 7Be depth penetration from this study decreases exponentially with depth and is confined within the top few centimeters and similar with other works been reported. The further discussion for this findings will be presented in full paper. (author)

  13. Capturing Motion and Depth Before Cinematography.

    Science.gov (United States)

    Wade, Nicholas J

    2016-01-01

    Visual representations of biological states have traditionally faced two problems: they lacked motion and depth. Attempts were made to supply these wants over many centuries, but the major advances were made in the early-nineteenth century. Motion was synthesized by sequences of slightly different images presented in rapid succession and depth was added by presenting slightly different images to each eye. Apparent motion and depth were combined some years later, but they tended to be applied separately. The major figures in this early period were Wheatstone, Plateau, Horner, Duboscq, Claudet, and Purkinje. Others later in the century, like Marey and Muybridge, were stimulated to extend the uses to which apparent motion and photography could be applied to examining body movements. These developments occurred before the birth of cinematography, and significant insights were derived from attempts to combine motion and depth.

  14. Plasma membrane ATPases

    DEFF Research Database (Denmark)

    Palmgren, Michael Broberg; Bækgaard, Lone; Lopez Marques, Rosa Laura

    2011-01-01

    The plasma membrane separates the cellular contents from the surrounding environment. Nutrients must enter through the plasma membrane in order to reach the cell interior, and toxic metabolites and several ions leave the cell by traveling across the same barrier. Biological pumps in the plasma me...

  15. Polymide gas separation membranes

    Science.gov (United States)

    Ding, Yong; Bikson, Benjamin; Nelson, Joyce Katz

    2004-09-14

    Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas separation properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.

  16. Enantioseparation with liquid membranes

    NARCIS (Netherlands)

    Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo

    Chiral resolution of racemic products is a challenging and important task in the pharmaceutical, agrochemical, flavor, polymer and fragrances industries. One of the options for these challenging separations is to use liquid membranes. Although liquid membranes have been known for almost four decades

  17. Silicon nitride nanosieve membrane

    NARCIS (Netherlands)

    Tong, D.H.; Jansen, Henricus V.; Gadgil, V.J.; Bostan, C.G.; Berenschot, Johan W.; van Rijn, C.J.M.; Elwenspoek, Michael Curt

    2004-01-01

    An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with

  18. Membrane capacitive deionization

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Wal, van der A.

    2010-01-01

    Membrane capacitive deionization (MCDI) is an ion-removal process based on applying an electrical potential difference across an aqueous solution which flows in between oppositely placed porous electrodes, in front of which ion-exchange membranes are positioned. Due to the applied potential, ions

  19. Photoresponsive nanostructured membranes

    KAUST Repository

    Madhavan, Poornima; Sutisna, Burhannudin; Sougrat, Rachid; Nunes, Suzana Pereira

    2016-01-01

    The perspective of adding stimuli-response to isoporous membranes stimulates the development of separation devices with pores, which would open or close under control of environment chemical composition, temperature or exposure to light. Changes in pH and temperature have been previously investigated. In this work, we demonstrate for the first time the preparation of photoresponsive isoporous membranes, applying self-assembly non-solvent induced phase separation to a new light responsive block copolymer. First, we optimized the membrane formation by using poly(styrene-b-anthracene methyl methacrylate-b-methylmethacrylate) (PS-b-PAnMMA-b-PMMA) copolymer, identifying the most suitable solvent, copolymer block length, and other parameters. The obtained final triblock copolymer membrane morphologies were characterized using atomic force and electron microscopy. The microscopic analysis reveals that the PS-b-PAnMMA-b-PMMA copolymer can form both lamellar and ordered hexagonal nanoporous structures on the membrane top layer in appropriate solvent compositions. The nanostructured membrane emits fluorescence due to the presence of the anthracene mid-block. On irradiation of light the PS-b-PAnMMA-b-PMMA copolymer membranes has an additional stimuli response. The anthracene group undergoes conformational changes by forming [4 + 4] cycloadducts and this alters the membrane's water flux and solute retention. © 2016 The Royal Society of Chemistry.

  20. Wavefield Extrapolation in Pseudo-depth Domain

    KAUST Repository

    Ma, Xuxin

    2011-12-11

    Wave-equation based seismic migration and inversion tools are widely used by the energy industry to explore hydrocarbon and mineral resources. By design, most of these techniques simulate wave propagation in a space domain with the vertical axis being depth measured from the surface. Vertical depth is popular because it is a straightforward mapping of the subsurface space. It is, however, not computationally cost-effective because the wavelength changes with local elastic wave velocity, which in general increases with depth in the Earth. As a result, the sampling per wavelength also increases with depth. To avoid spatial aliasing in deep fast media, the seismic wave is oversampled in shallow slow media and therefore increase the total computation cost. This issue is effectively tackled by using the vertical time axis instead of vertical depth. This is because in a vertical time representation, the "wavelength" is essentially time period for vertical rays. This thesis extends the vertical time axis to the pseudo-depth axis, which features distance unit while preserving the properties of the vertical time representation. To explore the potentials of doing wave-equation based imaging in the pseudo-depth domain, a Partial Differential Equation (PDE) is derived to describe acoustic wave in this new domain. This new PDE is inherently anisotropic because the use of a constant vertical velocity to convert between depth and vertical time. Such anisotropy results in lower reflection coefficients compared with conventional space domain modeling results. This feature is helpful to suppress the low wavenumber artifacts in reverse-time migration images, which are caused by the widely used cross-correlation imaging condition. This thesis illustrates modeling acoustic waves in both conventional space domain and pseudo-depth domain. The numerical tool used to model acoustic waves is built based on the lowrank approximation of Fourier integral operators. To investigate the potential

  1. Specific interaction of CXCR4 with CD4 and CD8α: Functional analysis of the CD4/CXCR4 interaction in the context of HIV-1 envelope glycoprotein-mediated membrane fusion

    International Nuclear Information System (INIS)

    Basmaciogullari, Stephane; Pacheco, Beatriz; Bour, Stephan; Sodroski, Joseph

    2006-01-01

    We investigated possible interactions between HIV-1 receptor (CD4) and the main coreceptors CXCR4 and CCR5. We found that CD4 and CXCR4 coexpressed in 293T cells form a complex that can be immunoprecipitated with antibodies directed against the extracellular domain of either protein. Mutagenesis revealed that the CD4/CXCR4 interaction maps to two previously uncharacterized basic motifs in the cytoplasmic domain of CD4. HIV-1 envelope glycoprotein-mediated membrane fusion was found to be independent of the ability of CD4 and CXCR4 to interact, whether fusion was studied in a virus-cell or a cell-cell model. However, this interaction might explain the adaptation of HIV-1 to CXCR4 as an alternative to CCR5. We found that CXCR4 also interacts with the cytoplasmic domain of CD8α in a way that is similar to the CD4/CXCR4 interaction. The CD4/CXCR4 and CD8α/CXCR4 interactions may thus be involved in cellular signaling pathways shared by the CD4 and CD8α molecules

  2. Fabrication and Molecular Transport Studies of Highly c-Oriented AFI Membranes

    KAUST Repository

    Liu, Yang; Zhang, Bing; Liu, Defei; Sheng, Ping; Lai, Zhiping

    2017-01-01

    -packed and c-oriented monolayer of plate-like seeds that is manually assembled on a porous alumina support. The straight channels in the membrane are not only aligned vertically along the membrane depth, but are also continuous without disruption. The transport

  3. From cooperative to uncorrelated clogging in cross-flow microfluidic membranes

    NARCIS (Netherlands)

    Zwieten, van Ralph; Laar, van de T.; Sprakel, J.H.B.; Schroen, C.G.P.H.

    2018-01-01

    The operational lifetime of filtration membranes is reduced by the clogging of pores and subsequent build-up of a fouling or cake layer. Designing membrane operations in which clogging is delayed or even mitigated completely, requires in-depth insight into its origins. Due to the complexity of the

  4. In-line measurement of transparent micro membranes

    DEFF Research Database (Denmark)

    Fugl, Jimmy; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2007-01-01

    The purpose of this work has been to develop a new measuring principle to bring down the time for quality assurance, and obtain larger uniformity of the end product, in a specific production line. The production concerns thin transparent micro membranes (approx 35 micron thickness) dispensed...... in micro cavities, each membrane consisting of several membrane layers. A quality control should be performed every time a new layer is dispensed. The paper describes a new way of measuring membrane thickness. The method was achieved through the use of a vision system, whereby the thickness of the thin...... transparent micro membrane is determined in terms of the light absorbance of the membrane substrate. The new and faster measuring method makes is possible to measure the thickness of individual membranes and perform a 100% quality control....

  5. Naturalistic depth perception and binocular vision

    OpenAIRE

    Maiello, G.

    2017-01-01

    Humans continuously move both their eyes to redirect their foveae to objects at new depths. To correctly execute these complex combinations of saccades, vergence eye movements and accommodation changes, the visual system makes use of multiple sources of depth information, including binocular disparity and defocus. Furthermore, during development, both fine-tuning of oculomotor control as well as correct eye growth are likely driven by complex interactions between eye movements, accommodation,...

  6. Generators for finite depth subfactor planar algebras

    Indian Academy of Sciences (India)

    The main result of Kodiyalam and Tupurani [3] shows that a subfactor planar algebra of finite depth is singly generated with a finite presentation. If P is a subfactor planar algebra of depth k, it is shown there that a single 2k-box generates P. It is natural to ask what the smallest s is such that a single s-box generates P. While ...

  7. FINANCIAL DEPTH AND FINANCIAL ACCESS IN INDONESIA

    OpenAIRE

    Sigit Setiawan

    2015-01-01

    This study is intended to analyze the current levels of financial depth and financial access in Indonesia and to analyze the factors affecting them. The analysis method used was a combination of descriptive quantitative, benchmarking, and literature reviews. The conclusion is that the financial depth in Indonesia has not shown a satisfactory level since it was the lowest, or the second lowest ranked country among the sampled countries. Meanwhile, the financial access in Indonesia is relativel...

  8. Nanoscale Membrane Domain Formation Driven by Cholesterol

    DEFF Research Database (Denmark)

    Javanainen, Matti; Martinez-Seara, Hector; Vattulainen, Ilpo

    2017-01-01

    Biological membranes generate specific functions through compartmentalized regions such as cholesterol-enriched membrane nanodomains that host selected proteins. Despite the biological significance of nanodomains, details on their structure remain elusive. They cannot be observed via microscopic...... dipalmitoylphosphatidylcholine and cholesterol - the "minimal standard" for nanodomain formation. The simulations reveal how cholesterol drives the formation of fluid cholesterol-rich nanodomains hosting hexagonally packed cholesterol-poor lipid nanoclusters, both of which show registration between the membrane leaflets....... The complex nanodomain substructure forms when cholesterol positions itself in the domain boundary region. Here cholesterol can also readily flip-flop across the membrane. Most importantly, replacing cholesterol with a sterol characterized by a less asymmetric ring region impairs the emergence of nanodomains...

  9. CO2 clearance by membrane lungs.

    Science.gov (United States)

    Sun, Liqun; Kaesler, Andreas; Fernando, Piyumindri; Thompson, Alex J; Toomasian, John M; Bartlett, Robert H

    2018-05-01

    Commercial membrane lungs are designed to transfer a specific amount of oxygen per unit of venous blood flow. Membrane lungs are much more efficient at removing CO 2 than adding oxygen, but the range of CO 2 transfer is rarely reported. Commercial membrane lungs were studied with the goal of evaluating CO 2 removal capacity. CO 2 removal was measured in 4 commercial membrane lungs under standardized conditions. CO 2 clearance can be greater than 4 times that of oxygen at a given blood flow when the gas to blood flow ratio is elevated to 4:1 or 8:1. The CO 2 clearance was less dependent on surface area and configuration than oxygen transfer. Any ECMO system can be used for selective CO 2 removal.

  10. A new polarized neutrons method for studying depth-inhomogeneously magnetized magnetic films

    International Nuclear Information System (INIS)

    Korneev, D.A.

    1990-01-01

    The main specific features of the process of polarized thermal neutrons specular reflection from the surface of depth-inhomogeneously magnetic films are considered theoretically. It is shown how using the method of specular reflection of polarized thermal neutrons from such a films surface, one may restore the depth distribution of the local magnetization vector M-vector(z). 9 refs

  11. Using Opaque Image Blur for Real-Time Depth-of-Field Rendering

    DEFF Research Database (Denmark)

    Kraus, Martin

    2011-01-01

    While depth of field is an important cinematographic means, its use in real-time computer graphics is still limited by the computational costs that are necessary to achieve a sufficient image quality. Specifically, color bleeding artifacts between objects at different depths are most effectively...

  12. Membrane technology and applications

    International Nuclear Information System (INIS)

    Khalil, F.H.

    1997-01-01

    The main purpose of this dissertation is to prepare and characterize some synthetic membranes obtained by radiation-induced graft copolymerization of and A Am unitary and binary system onto nylon-6 films. The optimum conditions at which the grafting process proceeded homogeneously were determined. Some selected properties of the prepared membranes were studied. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), x-ray diffraction (XRD), mechanical properties and U.V./vis, instruments and techniques were used to characterize the prepared membranes. The use of such membranes for the decontamination of radioactive waste and some heavy metal ions as water pollutants were investigated. These grafted membranes showed good cation exchange properties and may be of practical interest in waste water treatment whether this water was radioactive or not. 4 tabs., 68 figs., 146 refs

  13. Total Variation Depth for Functional Data

    KAUST Repository

    Huang, Huang

    2016-11-15

    There has been extensive work on data depth-based methods for robust multivariate data analysis. Recent developments have moved to infinite-dimensional objects such as functional data. In this work, we propose a new notion of depth, the total variation depth, for functional data. As a measure of depth, its properties are studied theoretically, and the associated outlier detection performance is investigated through simulations. Compared to magnitude outliers, shape outliers are often masked among the rest of samples and harder to identify. We show that the proposed total variation depth has many desirable features and is well suited for outlier detection. In particular, we propose to decompose the total variation depth into two components that are associated with shape and magnitude outlyingness, respectively. This decomposition allows us to develop an effective procedure for outlier detection and useful visualization tools, while naturally accounting for the correlation in functional data. Finally, the proposed methodology is demonstrated using real datasets of curves, images, and video frames.

  14. Membrane raft association is a determinant of plasma membrane localization.

    Science.gov (United States)

    Diaz-Rohrer, Blanca B; Levental, Kandice R; Simons, Kai; Levental, Ilya

    2014-06-10

    The lipid raft hypothesis proposes lateral domains driven by preferential interactions between sterols, sphingolipids, and specific proteins as a central mechanism for the regulation of membrane structure and function; however, experimental limitations in defining raft composition and properties have prevented unequivocal demonstration of their functional relevance. Here, we establish a quantitative, functional relationship between raft association and subcellular protein sorting. By systematic mutation of the transmembrane and juxtamembrane domains of a model transmembrane protein, linker for activation of T-cells (LAT), we generated a panel of variants possessing a range of raft affinities. These mutations revealed palmitoylation, transmembrane domain length, and transmembrane sequence to be critical determinants of membrane raft association. Moreover, plasma membrane (PM) localization was strictly dependent on raft partitioning across the entire panel of unrelated mutants, suggesting that raft association is necessary and sufficient for PM sorting of LAT. Abrogation of raft partitioning led to mistargeting to late endosomes/lysosomes because of a failure to recycle from early endosomes. These findings identify structural determinants of raft association and validate lipid-driven domain formation as a mechanism for endosomal protein sorting.

  15. Evaluation of direct membrane filtration and direct forward osmosis as concepts for compact and energy-positive municipal wastewater treatment.

    Science.gov (United States)

    Hey, Tobias; Bajraktari, Niada; Davidsson, Åsa; Vogel, Jörg; Madsen, Henrik Tækker; Hélix-Nielsen, Claus; Jansen, Jes la Cour; Jönsson, Karin

    2018-02-01

    Municipal wastewater treatment commonly involves mechanical, biological and chemical treatment steps to protect humans and the environment from adverse effects. Membrane technology has gained increasing attention as an alternative to conventional wastewater treatment due to increased urbanization. Among the available membrane technologies, microfiltration (MF) and forward osmosis (FO) have been selected for this study due to their specific characteristics, such as compactness and efficient removal of particles. In this study, two treatment concepts were evaluated with regard to their specific electricity, energy and area demands. Both concepts would fulfil the Swedish discharge demands for small- and medium-sized wastewater treatment plants at full scale: (1) direct MF and (2) direct FO with seawater as the draw solution. The framework of this study is based on a combination of data obtained from bench- and pilot-scale experiments applying direct MF and FO, respectively. Additionally, available complementary data from a Swedish full-scale wastewater treatment plant and the literature were used to evaluate the concepts in depth. The results of this study indicate that both concepts are net positive with respect to electricity and energy, as more biogas can be produced compared to that using conventional wastewater treatment. Furthermore, the specific area demand is significantly reduced. This study demonstrates that municipal wastewater could be treated in a more energy- and area-efficient manner with techniques that are already commercially available and with future membrane technology.

  16. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Adcock, K.D.; Fain, D.E.; James, D.L.; Powell, L.E.; Raj, T.; Roettger, G.E.; Sutton, T.G. [East Tennessee Technology Park, Oak Ridge, TN (United States)

    1997-12-01

    The separative performance of the authors` ceramic membranes has been determined in the past using a permeance test system that measured flows of pure gases through a membrane at temperatures up to 275 C. From these data, the separation factor was determined for a particular gas pair from the ratio of the pure gas specific flows. An important project goal this year has been to build a Mixed Gas Separation System (MGSS) for measuring the separation efficiencies of membranes at higher temperatures and using mixed gases. The MGSS test system has been built, and initial operation has been achieved. The MGSS is capable of measuring the separation efficiency of membranes at temperatures up to 600 C and pressures up to 100 psi using a binary gas mixture such as hydrogen/methane. The mixed gas is fed into a tubular membrane at pressures up to 100 psi, and the membrane separates the feed gas mixture into a permeate stream and a raffinate stream. The test membrane is sealed in a stainless steel holder that is mounted in a split tube furnace to permit membrane separations to be evaluated at temperatures up to 600 C. The compositions of the three gas streams are measured by a gas chromatograph equipped with thermal conductivity detectors. The test system also measures the temperatures and pressures of all three gas streams as well as the flow rate of the feed stream. These data taken over a range of flows and pressures permit the separation efficiency to be determined as a function of the operating conditions. A mathematical model of the separation has been developed that permits the data to be reduced and the separation factor for the membrane to be determined.

  17. EM Task 9 - Centrifugal membrane filtration

    International Nuclear Information System (INIS)

    Stepan, Daniel J.; Stevens, Bradley G.; Hetland, Melanie D.

    1999-01-01

    The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc)

  18. Systems and methods for using a boehmite bond-coat with polyimide membranes for gas separation

    Science.gov (United States)

    Polishchuk, Kimberly Ann

    2013-03-05

    The subject matter disclosed herein relates to gas separation membranes and, more specifically, to polyimide gas separation membranes. In an embodiment, a gas separation membrane includes a porous substrate, a substantially continuous polyimide membrane layer, and one or more layers of boehmite nanoparticles disposed between the porous substrate and the polyimide membrane layer to form a bond-coat layer. The bond-coat layer is configured to improve the adhesion of the polyimide membrane layer to the porous substrate, and the polyimide membrane layer has a thickness approximately 100 nm or less.

  19. Techno-economical evaluation of membrane based biogas upgrading system: A comparison between polymeric membrane and carbon membrane technology

    Directory of Open Access Journals (Sweden)

    Shamim Haider

    2016-10-01

    Full Text Available A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre (CHF membrane and compare with a commercially available polymeric membrane (polyimide through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO2, O2, N2. The CHF membrane was modified through oxidation, chemical vapour deposition (CVD and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres (PORCHFs significantly exceeded CHF performance showing higher CO2 permeance (0.021 m3(STP/m2 h bar and CO2/CH4 selectivity of 246 (5 bar feed vs 50 mbar permeate pressure. The highest performance recorded through experiments (CHF and PORCHF was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS. A 300 Nm3/h mixture of CO2/CH4 containing 30–50% CO2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover 99.5% CH4 with 97.5% purity. Net present value (NPV was calculated for base case and optimal pressure (50 bar for CHF and PORCHF. The results indicated that recycle ratio (recycle/feed ranged from 0.2 to 10, specific energy from 0.15 to 0.8 (kW/Nm3feed and specific membrane area from 45 to 4700 (m2/Nm3feed. The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm3 and a lifetime of 15 years, the techno-economic analysis showed that payback time for

  20. Two-Step Mechanism of Membrane Disruption by Aβ through Membrane Fragmentation and Pore Formation

    Science.gov (United States)

    Sciacca, Michele F.M.; Kotler, Samuel A.; Brender, Jeffrey R.; Chen, Jennifer; Lee, Dong-kuk; Ramamoorthy, Ayyalusamy

    2012-01-01

    Disruption of cell membranes by Aβ is believed to be one of the key components of Aβ toxicity. However, the mechanism by which this occurs is not fully understood. Here, we demonstrate that membrane disruption by Aβ occurs by a two-step process, with the initial formation of ion-selective pores followed by nonspecific fragmentation of the lipid membrane during amyloid fiber formation. Immediately after the addition of freshly dissolved Aβ1–40, defects form on the membrane that share many of the properties of Aβ channels originally reported from single-channel electrical recording, such as cation selectivity and the ability to be blockaded by zinc. By contrast, subsequent amyloid fiber formation on the surface of the membrane fragments the membrane in a way that is not cation selective and cannot be stopped by zinc ions. Moreover, we observed that the presence of ganglioside enhances both the initial pore formation and the fiber-dependent membrane fragmentation process. Whereas pore formation by freshly dissolved Aβ1–40 is weakly observed in the absence of gangliosides, fiber-dependent membrane fragmentation can only be observed in their presence. These results provide insights into the toxicity of Aβ and may aid in the design of specific compounds to alleviate the neurodegeneration of Alzheimer’s disease. PMID:22947931

  1. Depth resolution and preferential sputtering in depth profiling of sharp interfaces

    International Nuclear Information System (INIS)

    Hofmann, S.; Han, Y.S.; Wang, J.Y.

    2017-01-01

    Highlights: • Interfacial depth resolution from MRI model depends on sputtering rate differences. • Depth resolution critically depends on the dominance of roughness or atomic mixing. • True (depth scale) and apparent (time scale) depth resolutions are different. • Average sputtering rate approximately yields true from apparent depth resolution. • Profiles by SIMS and XPS are different but similar to surface concentrations. - Abstract: The influence of preferential sputtering on depth resolution of sputter depth profiles is studied for different sputtering rates of the two components at an A/B interface. Surface concentration and intensity depth profiles on both the sputtering time scale (as measured) and the depth scale are obtained by calculations with an extended Mixing-Roughness-Information depth (MRI)-model. The results show a clear difference for the two extreme cases (a) preponderant roughness and (b) preponderant atomic mixing. In case (a), the interface width on the time scale (Δt(16–84%)) increases with preferential sputtering if the faster sputtering component is on top of the slower sputtering component, but the true resolution on the depth scale (Δz(16–84%)) stays constant. In case (b), the interface width on the time scale stays constant but the true resolution on the depth scale varies with preferential sputtering. For similar order of magnitude of the atomic mixing and the roughness parameters, a transition state between the two extremes is obtained. While the normalized intensity profile of SIMS represents that of the surface concentration, an additional broadening effect is encountered in XPS or AES by the influence of the mean electron escape depth which may even cause an additional matrix effect at the interface.

  2. Depth resolution and preferential sputtering in depth profiling of sharp interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Han, Y.S. [Department of Physics, Shantou University, 243 Daxue Road, Shantou, 515063 Guangdong (China); Wang, J.Y., E-mail: wangjy@stu.edu.cn [Department of Physics, Shantou University, 243 Daxue Road, Shantou, 515063 Guangdong (China)

    2017-07-15

    Highlights: • Interfacial depth resolution from MRI model depends on sputtering rate differences. • Depth resolution critically depends on the dominance of roughness or atomic mixing. • True (depth scale) and apparent (time scale) depth resolutions are different. • Average sputtering rate approximately yields true from apparent depth resolution. • Profiles by SIMS and XPS are different but similar to surface concentrations. - Abstract: The influence of preferential sputtering on depth resolution of sputter depth profiles is studied for different sputtering rates of the two components at an A/B interface. Surface concentration and intensity depth profiles on both the sputtering time scale (as measured) and the depth scale are obtained by calculations with an extended Mixing-Roughness-Information depth (MRI)-model. The results show a clear difference for the two extreme cases (a) preponderant roughness and (b) preponderant atomic mixing. In case (a), the interface width on the time scale (Δt(16–84%)) increases with preferential sputtering if the faster sputtering component is on top of the slower sputtering component, but the true resolution on the depth scale (Δz(16–84%)) stays constant. In case (b), the interface width on the time scale stays constant but the true resolution on the depth scale varies with preferential sputtering. For similar order of magnitude of the atomic mixing and the roughness parameters, a transition state between the two extremes is obtained. While the normalized intensity profile of SIMS represents that of the surface concentration, an additional broadening effect is encountered in XPS or AES by the influence of the mean electron escape depth which may even cause an additional matrix effect at the interface.

  3. Microfabricated hydrogen sensitive membranes

    Energy Technology Data Exchange (ETDEWEB)

    Naddaf, A.; Kraetz, L. [Lehrstuhl fuer Thermische Verfahrenstechnik, Technische Universitaet Kaiserslautern (Germany); Detemple, P.; Schmitt, S.; Hessel, V. [Institut fuer Mikrotechnik Mainz GmbH, Mainz (Germany); Faqir, N. [University of Jordan, Amman (Jordan); Bart, H.J.

    2009-01-15

    Thin, defect-free palladium, palladium/copper and palladium/silver hydrogen absorbing membranes were microfabricated. A dual sputtering technique was used to deposit the palladium alloy membranes of only 1 {mu}m thickness on a nonporous silicon substrate. Advanced silicon etching (ASE) was applied on the backside to create a mechanically stable support structure for the thin films. Performance evaluation was carried out for different gases in a temperature range of 20 C to 298 C at a constant differential pressure of 110 kPa at the two sides of the membrane. The composite membranes show an excellent permeation rate of hydrogen, which appears to be 0.05 Pa m{sup 3} s{sup -1} and 0.01.10{sup -3} Pa m{sup 3} s{sup -1} at 20 C for the microfabricated 23 % silver and the 53 % copper composite membranes, respectively. The selectivity to hydrogen over a gas mixture containing, in addition to hydrogen, carbon monoxide, carbon dioxide and nitrogen was measured. The mass spectrometer did not detect any CO{sub 2} or CO, showing that the membrane is completely hydrogen selective. The microfabricated membranes exhibit both high mechanical strength (they easily withstand pressures up to 4 bar) and high thermal stability (up to 650 C). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  4. Catalytic nanoporous membranes

    Science.gov (United States)

    Pellin, Michael J; Hryn, John N; Elam, Jeffrey W

    2013-08-27

    A nanoporous catalytic membrane which displays several unique features Including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity. Also provided is a method for producing a catalytic membrane having flow-through pores and discreet catalytic clusters adhering to the inside surfaces of the pores.

  5. TRENDS IN ESTIMATED MIXING DEPTH DAILY MAXIMUMS

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R; Amy DuPont, A; Robert Kurzeja, R; Matt Parker, M

    2007-11-12

    Mixing depth is an important quantity in the determination of air pollution concentrations. Fireweather forecasts depend strongly on estimates of the mixing depth as a means of determining the altitude and dilution (ventilation rates) of smoke plumes. The Savannah River United States Forest Service (USFS) routinely conducts prescribed fires at the Savannah River Site (SRS), a heavily wooded Department of Energy (DOE) facility located in southwest South Carolina. For many years, the Savannah River National Laboratory (SRNL) has provided forecasts of weather conditions in support of the fire program, including an estimated mixing depth using potential temperature and turbulence change with height at a given location. This paper examines trends in the average estimated mixing depth daily maximum at the SRS over an extended period of time (4.75 years) derived from numerical atmospheric simulations using two versions of the Regional Atmospheric Modeling System (RAMS). This allows for differences to be seen between the model versions, as well as trends on a multi-year time frame. In addition, comparisons of predicted mixing depth for individual days in which special balloon soundings were released are also discussed.

  6. The ocean depths: Elf's target for 1997

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Elf has long since been aware of the potential of sedimentary basins in the ocean depths. For this reason, the group has been preparing to descend to these depths for many years. Today, it is setting itself the target of being ready to optimise as from 1997 a discovery made in the depth between 400 and 1500 m of water in Africa. In the Gulf of Guinea, most of the neighbouring countries have opened up their deep sea offshore areas, in order to try to renew their reserves on the verge of the third millennium. Indeed a great similarity can be seen between the West African and the Brazilian ocean depths. In the African offshore areas, Elf has acquired or renewed eight blocks, four of which are in Nigeria, one in the Congo, one in Gabon and two in Angola. The group is also interested in the ocean depths which are now accessible in the North Sea, whether in the Norwegian (Voring and More) of British (Western Shetlands) areas. (author). 1 fig

  7. Rotating bubble membrane radiator

    Science.gov (United States)

    Webb, Brent J.; Coomes, Edmund P.

    1988-12-06

    A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating bubble membrane radiator, where it is sprayed into the interior of the bubble. Liquid impacting upon the interior surface of the bubble is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.

  8. Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor.

    Science.gov (United States)

    Ranieri, Giuseppe; Mazzei, Rosalinda; Wu, Zhentao; Li, Kang; Giorno, Lidietta

    2016-03-14

    Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic hollow fibre membranes and their use in a two-separate-phase biocatalytic membrane reactor will be described. The asymmetric ceramic hollow fibre membranes were prepared using a combined phase inversion and sintering technique. The prepared fibres were then used as support for lipase covalent immobilization in order to develop a two-separate-phase biocatalytic membrane reactor. A functionalization method was proposed in order to increase the density of the reactive hydroxyl groups on the surface of ceramic membranes, which were then amino-activated and treated with a crosslinker. The performance and the stability of the immobilized lipase were investigated as a function of the amount of the immobilized biocatalytst. Results showed that it is possible to immobilize lipase on a ceramic membrane without altering its catalytic performance (initial residual specific activity 93%), which remains constant after 6 reaction cycles.

  9. Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor

    Directory of Open Access Journals (Sweden)

    Giuseppe Ranieri

    2016-03-01

    Full Text Available Biocatalytic membrane reactors (BMR combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic hollow fibre membranes and their use in a two-separate-phase biocatalytic membrane reactor will be described. The asymmetric ceramic hollow fibre membranes were prepared using a combined phase inversion and sintering technique. The prepared fibres were then used as support for lipase covalent immobilization in order to develop a two-separate-phase biocatalytic membrane reactor. A functionalization method was proposed in order to increase the density of the reactive hydroxyl groups on the surface of ceramic membranes, which were then amino-activated and treated with a crosslinker. The performance and the stability of the immobilized lipase were investigated as a function of the amount of the immobilized biocatalytst. Results showed that it is possible to immobilize lipase on a ceramic membrane without altering its catalytic performance (initial residual specific activity 93%, which remains constant after 6 reaction cycles.

  10. Depth sensitivity of Lexan polycarbonate detector

    CERN Document Server

    Awad, E M

    1999-01-01

    The dependence of the registration sensitivity of Lexan polycarbonate with depth inside the detector was studied. Samples of Lexan from General Electric were irradiated to two long range ions. These were Ni and Au ions with a projectile energy of 0.3 and 1 GeV/n. Two independent techniques, the track-diameter technique (TDT) and the track profile technique (TPT), were used. The registration sensitivity was measured at depths of 7, 10, 15, 18, 20, 28, 35 and 40 mu m inside the detector. The results of the two techniques show that the detector sensitivity decreases gradually with the depth inside the detector. It reaches 20 % less compared to sensitivity at the surface after 40 mu m have been removed.

  11. Wavefield extrapolation in pseudo-depth domain

    KAUST Repository

    Ma, Xuxin; Alkhalifah, Tariq Ali

    2012-01-01

    Extrapolating seismic waves in Cartesian coordinate is prone to uneven spatial sampling, because the seismic wavelength tends to grow with depth, as velocity increase. We transform the vertical depth axis to a pseudo one using a velocity weighted mapping, which can effectively mitigate this wavelength variation. We derive acoustic wave equations in this new domain based on the direct transformation of the Laplacian derivatives, which admits solutions that are more accurate and stable than those derived from the kinematic transformation. The anisotropic versions of these equations allow us to isolate the vertical velocity influence and reduce its impact on modeling and imaging. The major benefit of extrapolating wavefields in pseudo-depth space is its near uniform wavelength as opposed to the normally dramatic change of wavelength with the conventional approach. Time wavefield extrapolation on a complex velocity shows some of the features of this approach.

  12. Depth sectioning using electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    D'Alfonso, A J; Findlay, S D; Allen, L J; Cosgriff, E C; Kirkland, A I; Nellist, P D; Oxley, M P

    2008-01-01

    The continued development of electron probe aberration correctors for scanning transmission electron microscopy has enabled finer electron probes, allowing atomic resolution column-by-column electron energy loss spectroscopy. Finer electron probes have also led to a decrease in the probe depth of focus, facilitating optical slicing or depth sectioning of samples. The inclusion of post specimen aberration corrected image forming lenses allows for scanning confocal electron microscopy with further improved depth resolution and selectivity. We show that in both scanning transmission electron microscopy and scanning confocal electron microscopy geometries, by performing a three dimensional raster scan through a specimen and detecting electrons scattered with a characteristic energy loss, it will be possible to determine the location of isolated impurities embedded within the bulk.

  13. Depth resolved investigations of boron implanted silicon

    Science.gov (United States)

    Sztucki, M.; Metzger, T. H.; Milita, S.; Berberich, F.; Schell, N.; Rouvière, J. L.; Patel, J.

    2003-01-01

    We have studied the depth distribution and structure of defects in boron implanted silicon (0 0 1). Silicon wafers were implanted with a boron dose of 6×10 15 ions/cm -2 at 32 keV and went through different annealing treatments. Using diffuse X-ray scattering at grazing incidence and exit angles we are able to distinguish between different kinds of defects (point defect clusters and extrinsic stacking faults on {1 1 1} planes) and to determine their depth distribution as a function of the thermal budget. Cross-section transmission electron microscopy was used to gain complementary information. In addition we have determined the strain distribution caused by the boron implantation as a function of depth from rocking curve measurements.

  14. Photodegradation of wood and depth profile analysis

    International Nuclear Information System (INIS)

    Kataoka, Y.

    2008-01-01

    Photochemical degradation is a key process of the weathering that occurs when wood is exposed outdoors. It is also a major cause of the discoloration of wood in indoor applications. The effects of sunlight on the chemical composition of wood are superficial in nature, but estimates of the depth at which photodegradation occurs in wood vary greatly from 80 microm to as much as 2540 mic rom. Better understanding of the photodegradation of wood through depth profile analysis is desirable because it would allow the development of more effective photo-protective treatments that target the surface layers of wood most susceptible to photodegradation. This paper briefly describes fundamental aspects of photodegradation of wood and reviews progress made in the field of depth profile study on the photodegradation of wood. (author)

  15. Shallow surface depth profiling with atomic resolution

    International Nuclear Information System (INIS)

    Xi, J.; Dastoor, P.C.; King, B.V.; O'Connor, D.J.

    1999-01-01

    It is possible to derive atomic layer-by-layer composition depth profiles from popular electron spectroscopic techniques, such as X-ray photoelectron spectroscopy (XPS) or Auger electron spectroscopy (AES). When ion sputtering assisted AES or XPS is used, the changes that occur during the establishment of the steady state in the sputtering process make these techniques increasingly inaccurate for depths less than 3nm. Therefore non-destructive techniques of angle-resolved XPS (ARXPS) or AES (ARAES) have to be used in this case. In this paper several data processing algorithms have been used to extract the atomic resolved depth profiles of a shallow surface (down to 1nm) from ARXPS and ARAES data

  16. Factors controlling contrail cirrus optical depth

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2009-08-01

    Full Text Available Aircraft contrails develop into contrail cirrus by depositional growth and sedimentation of ice particles and horizontal spreading due to wind shear. Factors controlling this development include temperature, ice supersaturation, thickness of ice-supersaturated layers, and vertical gradients in the horizontal wind field. An analytical microphysical cloud model is presented and validated that captures these processes. Many individual contrail cirrus are simulated that develop differently owing to the variability in the controlling factors, resulting in large samples of cloud properties that are statistically analyzed. Contrail cirrus development is studied over the first four hours past formation, similar to the ages of line-shaped contrails that were tracked in satellite imagery on regional scales. On these time scales, contrail cirrus optical depth and microphysical variables exhibit a marked variability, expressed in terms of broad and skewed probability distribution functions. Simulated mean optical depths at a wavelength of 0.55 μm range from 0.05-0.5 and a substantial fraction 20-50% of contrail cirrus stay subvisible (optical depth <0.02, depending on meteorological conditions.

    A detailed analysis based on an observational case study over the continental USA suggests that previous satellite measurements of line-shaped persistent contrails have missed about 89%, 50%, and 11% of contrails with optical depths 0-0.05, 0.05-0.1, and 0.1-0.2, respectively, amounting to 65% of contrail coverage of all optical depths. When comparing observations with simulations and when estimating the contrail cirrus climate impact, not only mean values but also the variability in optical depth and microphysical properties need to be considered.

  17. High bit depth infrared image compression via low bit depth codecs

    DEFF Research Database (Denmark)

    Belyaev, Evgeny; Mantel, Claire; Forchhammer, Søren

    2017-01-01

    images via 8 bit depth codecs in the following way. First, an input 16 bit depth image is mapped into 8 bit depth images, e.g., the first image contains only the most significant bytes (MSB image) and the second one contains only the least significant bytes (LSB image). Then each image is compressed.......264/AVC codecs, which are usually available in efficient implementations, and compare their rate-distortion performance with JPEG2000, JPEG-XT and H.265/HEVC codecs supporting direct compression of infrared images in 16 bit depth format. A preliminary result shows that two 8 bit H.264/AVC codecs can...

  18. Efficient Depth Enhancement Using a Combination of Color and Depth Information.

    Science.gov (United States)

    Lee, Kyungjae; Ban, Yuseok; Lee, Sangyoun

    2017-07-01

    Studies on depth images containing three-dimensional information have been performed for many practical applications. However, the depth images acquired from depth sensors have inherent problems, such as missing values and noisy boundaries. These problems significantly affect the performance of applications that use a depth image as their input. This paper describes a depth enhancement algorithm based on a combination of color and depth information. To fill depth holes and recover object shapes, asynchronous cellular automata with neighborhood distance maps are used. Image segmentation and a weighted linear combination of spatial filtering algorithms are applied to extract object regions and fill disocclusion in the object regions. Experimental results on both real-world and public datasets show that the proposed method enhances the quality of the depth image with low computational complexity, outperforming conventional methods on a number of metrics. Furthermore, to verify the performance of the proposed method, we present stereoscopic images generated by the enhanced depth image to illustrate the improvement in quality.

  19. Molecular Transport Studies Through Unsupported Lipid Membranes

    Science.gov (United States)

    Rock, William; Parekh, Sapun; Bonn, Mischa

    2014-03-01

    Dendrimers, spherical polymeric nanoparticles made from branched monomers around a central core, show great promise as drug delivery vehicles. Dendrimer size, core contents, and surface functionality can be synthetically tuned, providing unprecedented versatility. Polyamidoamine (PAMAM) dendrimers have been shown to enter cells; however, questions remain about their biophysical interactions with the cell membrane, specifically about the presence and size of transient pores. We monitor dendrimer-lipid bilayer interactions using unsupported black lipid membranes (BLMs) as model cell membranes. Custom bilayer slides contain two vertically stacked aqueous chambers separated by a 25 μm Teflon sheet with a 120 μm aperture where the bilayer is formed. We vary the composition of model membranes (cholesterol content and lipid phase) to create biomimetic systems and study the interaction of PAMAM G6 and G3 dendrimers with these bilayers. Dendrimers, dextran cargo, and bilayers are monitored and quantified using time-lapse fluorescence imaging. Electrical capacitance measurements are simultaneously recorded to determine if the membrane is porous, and the pore size is deduced by monitoring transport of fluorescent dextrans of increasing molecular weight. These experiments shed light on the importance of cholesterol content and lipid phase on the interaction of dendrimer nanoparticles with membranes.

  20. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    to the variation in size of the proteins and a reasonable separation factor can be observed only when the size difference is in the order of 10 or more. This is partly caused by concentration polarization and membrane fouling which hinders an effective separation of the proteins. Application of an electric field...... across the porous membrane has been demonstrated to be an effective way to reduce concentration polarization and membrane fouling. In addition, this technique can also be used to separate the proteins based on difference in charge, which to some extent overcome the limitations of size difference...... of proteins on the basis of their charge, degree of hydrophobicity, affinity or size. Adequate purity is often not achieved unless several purification steps are combined thereby increasing cost and reducing product yield. Conventional fractionation of proteins using ultrafiltration membranes is limited...

  1. Fuel cell membrane humidification

    Science.gov (United States)

    Wilson, Mahlon S.

    1999-01-01

    A polymer electrolyte membrane fuel cell assembly has an anode side and a cathode side separated by the membrane and generating electrical current by electrochemical reactions between a fuel gas and an oxidant. The anode side comprises a hydrophobic gas diffusion backing contacting one side of the membrane and having hydrophilic areas therein for providing liquid water directly to the one side of the membrane through the hydrophilic areas of the gas diffusion backing. In a preferred embodiment, the hydrophilic areas of the gas diffusion backing are formed by sewing a hydrophilic thread through the backing. Liquid water is distributed over the gas diffusion backing in distribution channels that are separate from the fuel distribution channels.

  2. Wrinkles in reinforced membranes

    Science.gov (United States)

    Takei, Atsushi; Brau, Fabian; Roman, Benoît; Bico, José.

    2012-02-01

    We study, through model experiments, the buckling under tension of an elastic membrane reinforced with a more rigid strip or a fiber. In these systems, the compression of the rigid layer is induced through Poisson contraction as the membrane is stretched perpendicularly to the strip. Although strips always lead to out-of-plane wrinkles, we observe a transition from out-of-plane to in plane wrinkles beyond a critical strain in the case of fibers embedded into the elastic membranes. The same transition is also found when the membrane is reinforced with a wall of the same material depending on the aspect ratio of the wall. We describe through scaling laws the evolution of the morphology of the wrinkles and the different transitions as a function of material properties and stretching strain.

  3. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-02-01

    This factsheet describes a research project that will focus on the development and application of nonporous high gas flux perfluoro membranes with high temperature rating and excellent chemical resistance.

  4. Depth resolution of secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Pustovit, A.N.

    2004-01-01

    The effect of the solid body discreteness in the direction of the normal to the sample surface on the depth resolution of the secondary ion mass spectrometry method is analyzed. It is shown that for this case the dependence of the width at the semi-height of the delta profiles of the studied elements depth distribution on the energy and angle of incidence of the initial ions should have the form of the stepwise function. This is experimentally proved by the silicon-germanium delta-layers in the silicon samples [ru

  5. FINANCIAL DEPTH AND FINANCIAL ACCESS IN INDONESIA

    OpenAIRE

    Sigit Setiawan

    2015-01-01

    This study is intended to analyse the current levels of financial depth and financial access in Indonesia and to analyse the factors affecting them. The analysis method used was a combination of descriptive quantitative, benchmarking, and literature reviews. The conclusion is that the financial depth in Indonesia has not shown a satisfactory level since it was the lowest, or the second lowest ranked country among the sampled countries. Meanwhile, the financial access in Indonesia is relativel...

  6. Financial Depth and Financial Access in Indonesia

    OpenAIRE

    Setiawan, Sigit

    2015-01-01

    This study is intended to analyse the current levels of financial depth and financial access in Indonesia and to analyse the factors affecting them. The analysis method used was a combination of descriptive quantitative, benchmarking, and literature reviews. The conclusion is that the financial depth in Indonesia has not shown a satisfactory level since it was the lowest, or the second lowest ranked country among the sampled countries. Meanwhile, the financial access in Indonesia is relativel...

  7. Defence in depth in nuclear safety

    International Nuclear Information System (INIS)

    Jayakumar, J.S.

    2016-01-01

    Nuclear energy is clean and can prevent global warming and hence it has a lot of importance in the current world. In order for the safe and reliable operation of the NPP, a defence in depth concept has been practised, so that even one level of protection fails the subsequent one will contain the hazardous situation. Various levels, both from consideration of the physical barriers and implementation are described in this paper. Three major accidents happened in nuclear reactors are analysed from the defence in depth concept and shortcomings are discussed. (author)

  8. Knee Kinetics during Squats of Varying Loads and Depths in Recreationally Trained Females.

    Science.gov (United States)

    Flores, Victoria; Becker, James; Burkhardt, Eric; Cotter, Joshua

    2018-03-06

    The back squat exercise is typically practiced with varying squat depths and barbell loads. However, depth has been inconsistently defined, resulting in unclear safety precautions when squatting with loads. Additionally, females exhibit anatomical and kinematic differences to males which may predispose them to knee joint injuries. The purpose of this study was to characterize peak knee extensor moments (pKEMs) at three commonly practiced squat depths of above parallel, parallel, and full depth, and with three loads of 0% (unloaded), 50%, and 85% depth-specific one repetition maximum (1RM) in recreationally active females. Nineteen females (age, 25.1 ± 5.8 years; body mass, 62.5 ± 10.2 kg; height, 1.6 ± 0.10 m; mean ± SD) performed squats of randomized depth and load. Inverse dynamics were used to obtain pKEMs from three-dimensional knee kinematics. Depth and load had significant interaction effects on pKEMs (p = 0.014). Significantly greater pKEMs were observed at full depth compared to parallel depth with 50% 1RM load (p = 0.001, d = 0.615), and 85% 1RM load (p = 0.010, d = 0.714). Greater pKEMs were also observed at full depth compared to above parallel depth with 50% 1RM load (p = 0.003, d = 0.504). Results indicate effect of load on female pKEMs do not follow a progressively increasing pattern with either increasing depth or load. Therefore, when high knee loading is a concern, individuals are must carefully consider both the depth of squat being performed and the relative load they are using.

  9. Temperature responsive track membranes

    International Nuclear Information System (INIS)

    Omichi, H.; Yoshido, M.; Asano, M.; Tamada, H.

    1994-01-01

    A new track membrane was synthesized by introducing polymeric hydrogel to films. Such a monomer as amino acid group containing acryloyl or methacryloyl was either co-polymerized with diethylene glycol-bis-ally carbonate followed by on beam irradiation and chemical etching, or graft co-polymerized onto a particle track membrane of CR-39. The pore size was controlled in water by changing the water temperature. Some films other than CR-39 were also examined. (author). 11 refs, 7 figs

  10. The Cirque du Soleil of Golgi membrane dynamics.

    Science.gov (United States)

    Bankaitis, Vytas A

    2009-07-27

    The role of lipid metabolic enzymes in Golgi membrane remodeling is a subject of intense interest. Now, in this issue, Schmidt and Brown (2009. J. Cell Biol. doi:10.1083/jcb.200904147) report that lysophosphatidic acid-specific acyltransferase, LPAAT3, contributes to Golgi membrane dynamics by suppressing tubule formation.

  11. The Cirque du Soleil of Golgi membrane dynamics

    OpenAIRE

    Bankaitis, Vytas A.

    2009-01-01

    The role of lipid metabolic enzymes in Golgi membrane remodeling is a subject of intense interest. Now, in this issue, Schmidt and Brown (2009. J. Cell Biol. doi:10.1083/jcb.200904147) report that lysophosphatidic acid?specific acyltransferase, LPAAT3, contributes to Golgi membrane dynamics by suppressing tubule formation.

  12. Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography.

    Science.gov (United States)

    Vu, Anh T; Wang, Xinying; Wickramasinghe, S Ranil; Yu, Bing; Yuan, Hua; Cong, Hailin; Luo, Yongli; Tang, Jianguo

    2015-08-01

    Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Fabrication of electrospun nanofibrous membranes for membrane distillation application

    KAUST Repository

    Francis, Lijo

    2013-02-01

    Nanofibrous membranes of Matrimid have been successfully fabricated using an electrospinning technique under optimized conditions. Nanofibrous membranes are found to be highly hydrophobic with a high water contact angle of 130°. Field emission scanning electron microscopy and pore size distribution analysis revealed the big pore size structure of electrospun membranes to be greater than 2 μm and the pore size distribution is found to be narrow. Flat sheet Matrimid membranes were fabricated via casting followed by phase inversion. The morphology, pore size distribution, and water contact angle were measured and compared with the electrospun membranes. Both membranes fabricated by electrospinning and phase inversion techniques were tested in a direct contact membrane distillation process. Electrospun membranes showed high water vapor flux of 56 kg/m2-h, which is very high compared to the casted membrane as well as most of the fabricated and commercially available highly hydrophobic membranes. ©2013 Desalination Publications.

  14. Probing cellular behaviors through nanopatterned chitosan membranes

    International Nuclear Information System (INIS)

    Yang, Chung-Yao; Sung, Chun-Yen; Shuai, Hung-Hsun; Cheng, Chao-Min; Yeh, J Andrew

    2013-01-01

    This paper describes a high-throughput method for developing physically modified chitosan membranes to probe the cellular behavior of MDCK epithelial cells and HIG-82 fibroblasts adhered onto these modified membranes. To prepare chitosan membranes with micro/nanoscaled features, we have demonstrated an easy-to-handle, facile approach that could be easily integrated with IC-based manufacturing processes with mass production potential. These physically modified chitosan membranes were observed by scanning electron microscopy to gain a better understanding of chitosan membrane surface morphology. After MDCK cells and HIG-82 fibroblasts were cultured on these modified chitosan membranes for various culture durations (i.e. 1, 2, 4, 12 and 24 h), they were investigated to decipher cellular behavior. We found that both cells preferred to adhere onto a flat surface rather than on a nanopatterned surface. However, most (> 80%) of the MDCK cells showed rounded morphology and would suspend in the cultured medium instead of adhering onto the planar surface of negatively nanopatterned chitosan membranes. This means different cell types (e.g. fibroblasts versus epithelia) showed distinct capabilities/preferences of adherence for materials of varying surface roughness. We also showed that chitosan membranes could be re-used at least nine times without significant contamination and would provide us consistency for probing cell–material interactions by permitting reuse of the same substrate. We believe these results would provide us better insight into cellular behavior, specifically, microscopic properties and characteristics of cells grown under unique, nanopatterned cell-interface conditions. (paper)

  15. Far Western: probing membranes.

    Science.gov (United States)

    Einarson, Margret B; Pugacheva, Elena N; Orlinick, Jason R

    2007-08-01

    INTRODUCTIONThe far-Western technique described in this protocol is fundamentally similar to Western blotting. In Western blots, an antibody is used to detect a query protein on a membrane. In contrast, in a far-Western blot (also known as an overlay assay) the antibody is replaced by a recombinant GST fusion protein (produced and purified from bacteria), and the assay detects the interaction of this protein with target proteins on a membrane. The membranes are washed and blocked, incubated with probe protein, washed again, and subjected to autoradiography. The GST fusion (probe) proteins are often labeled with (32)P; alternatively, the membrane can be probed with unlabeled GST fusion protein, followed by detection using commercially available GST antibodies. The nonradioactive approach is substantially more expensive (due to the purchase of antibody and detection reagents) than using radioactively labeled proteins. In addition, care must be taken to control for nonspecific interactions with GST alone and a signal resulting from antibody cross-reactivity. In some instances, proteins on the membrane are not able to interact after transfer. This may be due to improper folding, particularly in the case of proteins expressed from a phage expression library. This protocol describes a way to overcome this by washing the membrane in denaturation buffer, which is then serially diluted to permit slow renaturation of the proteins.

  16. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-10-01

    This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  17. Bacterial membrane proteomics.

    Science.gov (United States)

    Poetsch, Ansgar; Wolters, Dirk

    2008-10-01

    About one quarter to one third of all bacterial genes encode proteins of the inner or outer bacterial membrane. These proteins perform essential physiological functions, such as the import or export of metabolites, the homeostasis of metal ions, the extrusion of toxic substances or antibiotics, and the generation or conversion of energy. The last years have witnessed completion of a plethora of whole-genome sequences of bacteria important for biotechnology or medicine, which is the foundation for proteome and other functional genome analyses. In this review, we discuss the challenges in membrane proteome analysis, starting from sample preparation and leading to MS-data analysis and quantification. The current state of available proteomics technologies as well as their advantages and disadvantages will be described with a focus on shotgun proteomics. Then, we will briefly introduce the most abundant proteins and protein families present in bacterial membranes before bacterial membrane proteomics studies of the last years will be presented. It will be shown how these works enlarged our knowledge about the physiological adaptations that take place in bacteria during fine chemical production, bioremediation, protein overexpression, and during infections. Furthermore, several examples from literature demonstrate the suitability of membrane proteomics for the identification of antigens and different pathogenic strains, as well as the elucidation of membrane protein structure and function.

  18. Membrane topology analysis of HIV-1 envelope glycoprotein gp41

    Directory of Open Access Journals (Sweden)

    Xiao Dan

    2010-11-01

    Full Text Available Abstract Background The gp41 subunit of the HIV-1 envelope glycoprotein (Env has been widely regarded as a type I transmembrane protein with a single membrane-spanning domain (MSD. An alternative topology model suggested multiple MSDs. The major discrepancy between the two models is that the cytoplasmic Kennedy sequence in the single MSD model is assigned as the extracellular loop accessible to neutralizing antibodies in the other model. We examined the membrane topology of the gp41 subunit in both prokaryotic and mammalian systems. We attached topological markers to the C-termini of serially truncated gp41. In the prokaryotic system, we utilized a green fluorescent protein (GFP that is only active in the cytoplasm. The tag protein (HaloTag and a membrane-impermeable ligand specific to HaloTag was used in the mammalian system. Results In the absence of membrane fusion, both the prokaryotic and mammalian systems (293FT cells supported the single MSD model. In the presence of membrane fusion in mammalian cells (293CD4 cells, the data obtained seem to support the multiple MSD model. However, the region predicted to be a potential MSD is the highly hydrophilic Kennedy sequence and is least likely to become a MSD based on several algorithms. Further analysis revealed the induction of membrane permeability during membrane fusion, allowing the membrane-impermeable ligand and antibodies to cross the membrane. Therefore, we cannot completely rule out the possible artifacts. Addition of membrane fusion inhibitors or alterations of the MSD sequence decreased the induction of membrane permeability. Conclusions It is likely that a single MSD model for HIV-1 gp41 holds true even in the presence of membrane fusion. The degree of the augmentation of membrane permeability we observed was dependent on the membrane fusion and sequence of the MSD.

  19. Antifouling enhancement of polysulfone/TiO2 nanocomposite separation membrane by plasma etching

    Science.gov (United States)

    Chen, Z.; Yin, C.; Wang, S.; Ito, K.; Fu, Q. M.; Deng, Q. R.; Fu, P.; Lin, Z. D.; Zhang, Y.

    2017-01-01

    A polysulfone/TiO2 nanocomposite membrane was prepared via casting method, followed by the plasma etching of the membrane surface. Doppler broadened energy spectra vs. positron incident energy were employed to elucidate depth profiles of the nanostructure for the as-prepared and treated membranes. The results confirmed that the near-surface of the membrane was modified by the plasma treatment. The antifouling characteristics for the membranes, evaluated using the degradation of Rhodamin B, indicated that the plasma treatment enhances the photo catalytic ability of the membrane, suggesting that more TiO2 nanoparticles are exposed at the membrane surface after the plasma treatment as supported by the positron result.

  20. Antifouling enhancement of polysulfone/TiO2 nanocomposite separation membrane by plasma etching

    International Nuclear Information System (INIS)

    Chen, Z; Yin, C; Wang, S; Fu, Q M; Deng, Q R; Fu, P; Lin, Z D; Zhang, Y; Ito, K

    2017-01-01

    A polysulfone/TiO 2 nanocomposite membrane was prepared via casting method, followed by the plasma etching of the membrane surface. Doppler broadened energy spectra vs. positron incident energy were employed to elucidate depth profiles of the nanostructure for the as-prepared and treated membranes. The results confirmed that the near-surface of the membrane was modified by the plasma treatment. The antifouling characteristics for the membranes, evaluated using the degradation of Rhodamin B, indicated that the plasma treatment enhances the photo catalytic ability of the membrane, suggesting that more TiO 2 nanoparticles are exposed at the membrane surface after the plasma treatment as supported by the positron result. (paper)