WorldWideScience

Sample records for immobilized photosynthetic membranes

  1. Membranes suited for immobilizing biomolecules

    NARCIS (Netherlands)

    2009-01-01

    The present invention relates to flow-through membranes suitable for the immobilization of biomols., methods for the prepn. of such membranes and the use of such membranes for the immobilization of biomols. and subsequent detection of immobilized biomols. The invention concerns a flow-through

  2. Immobilized fluid membranes for gas separation

    Science.gov (United States)

    Liu, Wei; Canfield, Nathan L; Zhang, Jian; Li, Xiaohong Shari; Zhang, Jiguang

    2014-03-18

    Provided herein are immobilized liquid membranes for gas separation, methods of preparing such membranes and uses thereof. In one example, the immobilized membrane includes a porous metallic host matrix and an immobilized liquid fluid (such as a silicone oil) that is immobilized within one or more pores included within the porous metallic host matrix. The immobilized liquid membrane is capable of selective permeation of one type of molecule (such as oxygen) over another type of molecule (such as water). In some examples, the selective membrane is incorporated into a device to supply oxygen from ambient air to the device for electrochemical reactions, and at the same time, to block water penetration and electrolyte loss from the device.

  3. Biomaterials based on photosynthetic membranes as potential sensors for herbicides.

    Science.gov (United States)

    Ventrella, Andrea; Catucci, Lucia; Placido, Tiziana; Longobardi, Francesco; Agostiano, Angela

    2011-08-15

    In this study, ultrathin film multilayers of Photosystem II-enriched photosynthetic membranes (BBY) were prepared and immobilized on quartz substrates by means of a Layer by Layer procedure exploiting electrostatic interactions with poly(ethylenimine) as polyelectrolyte. The biomaterials thus obtained were characterized by means of optical techniques and Atomic Force Microscopy, highlighting the fact that the Layer by Layer approach allowed the BBYs to be immobilized with satisfactory results. The activity of these hybrid materials was evaluated by means of optical assays based on the Hill Reaction, indicating that the biosamples, which preserved about 65% of their original activity even ten weeks after preparation, were both stable and active. Furthermore, an investigation of the biochips' sensitivity to the herbicide terbutryn, as a model analyte, gave interesting results: inhibition of photosynthetic activity was observed at terbutryn concentrations higher than 10(-7)M, thus evidencing the potential of such biomaterials in the environmental biosensor field. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Multilayer models of photosynthetic membranes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Brocklehurst, J R; Flanagan, M T

    1982-01-01

    The primary aim of this project has been to build an artificial membrane in which is incorporated, in a functional state, the protein bacteriorhodopsin responsible for generating an electrical potential difference across the membrane of the photosynthetic bacterium, halobacterium halobium, and to investigate the use of this artificial system as the basis of a solar cell. the bacteriorhodopsin has been incorporated into Langmuir-Blodgett multilayers. If ths supporting filter is then illuminated, a potential difference is generated between the two compartments. The lipid in the filter appears to act as a charge carrier for protons, the charge species that forms the electrochemical gradient generated by the bacteriorhodopsin when this molecule absorbs light. The internal resistances of such solar cells were determined and found to be so high that the cells could not be seriously considered as competitors with classical semiconductor cells. Multilayerswere deposited onto filters in which ion carriers that make the filters permeable to sodium ions had been dissolved in the paraffin. The photovoltage obtained indicated that protons transferred from one side of the filter to the other by the action of the bacteriorhodopsin were bing exchanged for sodium ions. A secondary aim of the project has been to examine the possibility of depositing mixed multilayers of a dye and a long chain quinone onto a semiconductor surface. A sensitizing multilayer has been prepared and the mobility of long chain quinones within the layers is high enough to warrant further research. However, it was found that, with the dyes and quinones used, quenched complexes were formed which would not act as sensitizers.

  5. Laboratory assessment of bioleaching of shallow eutrophic sediment by immobilized photosynthetic bacteria.

    Science.gov (United States)

    Sun, Shiyong; Fan, Shenglan; Shen, Kexuan; Lin, Shen; Nie, Xiaoqin; Liu, Mingxue; Dong, Faqin; Li, Jian

    2017-10-01

    Eutrophic sediment is a serious problem in ecosystem restoration, especially in shallow lake ecosystems. We present a novel bioleaching approach to treat shallow eutrophic sediment with the objective of preventing the release of nitrate, phosphate, and organic compounds from the sediment to the water column, using porous mineral-immobilized photosynthetic bacteria (PSB). Bioactivity of bacteria was maintained during the immobilization process. Immobilized PSB beads were directly deposited on the sediment surface. The deposited PSB utilized pollutants diffused from the sediment as a nutritive matrix for growth. We evaluated the effects of light condition, temperature, initial pH, amount of PSB beads, and frequency of addition of PSB beads for contaminant removal efficiency during bioleaching operations. The presented study indicated that immobilized PSB beads using porous minerals as substrates have considerable application potential in bioremediation of shallow eutrophic lakes.

  6. Fouling-induced enzyme immobilization for membrane reactors

    DEFF Research Database (Denmark)

    Luo, Jianquan; Meyer, Anne S.; Jonsson, Gunnar Eigil

    2013-01-01

    A simple enzyme immobilization method accomplished by promoting membrane fouling formation is proposed. The immobilization method is based on adsorption and entrapment of the enzymes in/on the membrane. To evaluate the concept, two membrane orientations, skin layer facing feed (normal mode......, but the reverse mode allowed for higher enzyme loading and stability, and irreversible fouling (i.e. pore blocking) developed more readily in the support structure than in the skin layer. Compared with an enzymatic membrane reactor (EMR) with free enzymes, the novel EMR with enzymes immobilized in membrane......) and support layer facing feed (reverse mode), were used to immobilize alcohol dehydrogenase (ADH, EC 1.1.1.1) and glutamate dehydrogenase (GDH, EC 1.4.1.3), respectively. The nature of the fouling in each mode was determined by filtration fouling models. The permeate flux was larger in the normal mode...

  7. Ceramic membrane microfilter as an immobilized enzyme reactor.

    Science.gov (United States)

    Harrington, T J; Gainer, J L; Kirwan, D J

    1992-10-01

    This study investigated the use of a ceramic microfilter as an immobilized enzyme reactor. In this type of reactor, the substrate solution permeates the ceramic membrane and reacts with an enzyme that has been immobilized within its porous interior. The objective of this study was to examine the effect of permeation rate on the observed kinetic parameters for the immobilized enzyme in order to assess possible mass transfer influences or shear effects. Kinetic parameters were found to be independent of flow rate for immobilized penicillinase and lactate dehydrogenase. Therefore, neither mass transfer nor shear effects were observed for enzymes immobilized within the ceramic membrane. Both the residence time and the conversion in the microfilter reactor could be controlled simply by regulating the transmembrane pressure drop. This study suggests that a ceramic microfilter reactor can be a desirable alternative to a packed bed of porous particles, especially when an immobilized enzyme has high activity and a low Michaelis constant.

  8. Preparation of immobilized enzyme membrane by radiation-cast-polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1989-01-01

    The preparation of immobilized enzyme membranes was studied by radiation cast-polymerization at low temperatures using cellulase enzyme, hydrophilic and hydrophobic monomers. The enzyme activity of the membranes was affected by monomer concentration, membrane thickness, and hydrophilicity of monomer, in which the membranes with 100 μm thickness from high monomer concentration (80%) had high enzyme activity, which was similar to that of the membranes with 1.0 mm thickness from low monomer concentration (20%). (author)

  9. Characterization of cellulose acetate micropore membrane immobilized acylase I.

    Science.gov (United States)

    Guo, Yong-Sheng; Wang, Jie; Song, Xi-Jin

    2004-12-01

    This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was obtained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90 degrees C, which is higher than that of free acylase I (60 degrees C). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.

  10. Revealing Linear Aggregates of Light Harvesting Antenna Proteins in Photosynthetic Membranes

    OpenAIRE

    He, Yufan; Zeng, Xiaohua; Mukherjee, Saptarshi; Rajapaksha, Suneth; Kaplan, Samuel; Lu, H. Peter

    2010-01-01

    How light energy is harvested in a natural photosynthetic membrane through energy transfer is closely related to the stoichiometry and arrangement of light harvesting antenna proteins in the membrane. The specific photosynthetic architecture facilitates a rapid and efficient energy transfer among the light harvesting proteins (LH2 and LH1) and to the reaction center. Here we report the identification of linear aggregates of light harvesting proteins, LH2, in the photosynthetic membranes under...

  11. Poly(acrylonitrile)chitosan composite membranes for urease immobilization.

    Science.gov (United States)

    Gabrovska, Katya; Georgieva, Aneliya; Godjevargova, Tzonka; Stoilova, Olya; Manolova, Nevena

    2007-05-10

    (Poly)acrylonitrile/chitosan (PANCHI) composite membranes were prepared. The chitosan layer was deposited on the surface as well as on the pore walls of the base membrane. This resulted in the reduction of the pore size of the membrane and in an increase of their hydrophilicity. The pore structure of PAN and PANCHI membranes were determined by TEM and SEM analyses. It was found that the average size of the pore under a selective layer base PAN membrane is 7 microm, while the membrane coated with 0.25% chitosan shows a reduced pore size--small or equal to 5 microm and with 0.35% chitosan--about 4 microm. The amounts of the functional groups, the degree of hydrophilicity and transport characteristics of PAN/Chitosan composite membranes were determined. Urease was covalently immobilized onto all kinds of PAN/chitosan composite membranes using glutaraldehyde. Both the amount of bound protein and relative activity of immobilized urease were measured. The highest activity (94%) was measured for urease bound to PANCHI2 membranes (0.25% chitosan). The basic characteristics (pH(opt), pH(stability), T(opt), T(stability), heat inactivation and storage stability) of immobilized urease were determined. The obtained results show that the poly(acrylonitrile)chitosan composite membranes are suitable for enzyme immobilization.

  12. Atomic force microscopy studies of native photosynthetic membranes.

    Science.gov (United States)

    Sturgis, James N; Tucker, Jaimey D; Olsen, John D; Hunter, C Neil; Niederman, Robert A

    2009-05-05

    In addition to providing the earliest surface images of a native photosynthetic membrane at submolecular resolution, examination of the intracytoplasmic membrane (ICM) of purple bacteria by atomic force microscopy (AFM) has revealed a wide diversity of species-dependent arrangements of closely packed light-harvesting (LH) antennae, capable of fulfilling the basic requirements for efficient collection, transmission, and trapping of radiant energy. A highly organized architecture was observed with fused preparations of the pseudocrystalline ICM of Blastochloris viridis, consiting of hexagonally packed monomeric reaction center light-harvesting 1 (RC-LH1) core complexes. Among strains which also form a peripheral LH2 antenna, images of ICM patches from Rhodobacter sphaeroides exhibited well-ordered, interconnected networks of dimeric RC-LH1 core complexes intercalated by rows of LH2, coexisting with LH2-only domains. Other peripheral antenna-containing species, notably Rhodospirillum photometricum and Rhodopseudomonas palustris, showed a less regular organization, with mixed regions of LH2 and RC-LH1 cores, intermingled with large, paracrystalline domains. The ATP synthase and cytochrome bc(1) complex were not observed in any of these topographs and are thought to be localized in the adjacent cytoplasmic membrane or in inaccessible ICM regions separated from the flat regions imaged by AFM. The AFM images have served as a basis for atomic-resolution modeling of the ICM vesicle surface, as well as forces driving segregation of photosynthetic complexes into distinct domains. Docking of atomic-resolution molecular structures into AFM topographs of Rsp. photometricum membranes generated precise in situ structural models of the core complex surrounded by LH2 rings and a region of tightly packed LH2 complexes. A similar approach has generated a model of the highly curved LH2-only membranes of Rba. sphaeroides which predicts that sufficient space exists between LH2 complexes

  13. Study of glucoamylase immobilization in butadiene nitrile latex membrane

    International Nuclear Information System (INIS)

    Miller, E.

    1992-01-01

    Attempts have been undetaken to immobilize glucoamylaze by means of butadiene nitrile latex in the presence of a chemical initiator and 60 Co γ-radiation. The activity, stability of conjugates in the membrane and permeability of oxygen in these membranes were determined. (author) 14 refs.; 5 figs

  14. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J.

    2015-11-01

    Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum.

  15. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes.

    Science.gov (United States)

    Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J

    2015-11-03

    Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  16. Non-cooperative immobilization of residual water bound in lyophilized photosynthetic lamellae.

    Science.gov (United States)

    Harańczyk, Hubert; Baran, Ewelina; Nowak, Piotr; Florek-Wojciechowska, Małgorzata; Leja, Anna; Zalitacz, Dorota; Strzałka, Kazimierz

    2015-12-01

    This study applied 1H-NMR in time and in frequency domain measurements to monitor the changes that occur in bound water dynamics at decreased temperature and with increased hydration level in lyophilizates of native wheat photosynthetic lamellae and in photosynthetic lamellae reconstituted from lyophilizate. Proton relaxometry (measured as free induction decay = FID) distinguishes a Gaussian component S within the NMR signal (o). This comes from protons of the solid matrix of the lamellae and consists of (i) an exponentially decaying contribution L1 from mobile membrane protons, presumably from lipids, and from water that is tightly bound to the membrane surface and thus restricted in mobility; and (ii) an exponentially decaying component L2 from more mobile, loosely bound water pool. Both proton relaxometry data and proton spectroscopy show that dry lyophilizate incubated in dry air, i.e., at a relative humidity (p/p0) of 0% reveals a relatively high hydration level. The observed liquid signal most likely originates from mobile membrane protons and a tightly bound water fraction that is sealed in pores of dry lyophilizate and thus restricted in mobility. The estimations suggest that the amount of sealed water does not exceed the value characteristic for the main hydration shell of a phospholipid. Proton spectra collected for dry lyophilizate of photosynthetic lamellae show a continuous decrease in the liquid signal component without a distinct freezing transition when it is cooled down to -60ºC, which is significantly lower than the homogeneous ice nucleation temperature [Bronshteyn, V.L. et al. Biophys. J. 65 (1993) 1853].

  17. Plasma membrane isolation using immobilized concanavalin A magnetic beads.

    Science.gov (United States)

    Lee, Yu-Chen; Srajer Gajdosik, Martina; Josic, Djuro; Lin, Sue-Hwa

    2012-01-01

    Isolation of highly purified plasma membranes is the key step in constructing the plasma membrane proteome. Traditional plasma membrane isolation method takes advantage of the differential density of organelles. While differential centrifugation methods are sufficient to enrich for plasma membranes, the procedure is lengthy and results in low recovery of the membrane fraction. Importantly, there is significant contamination of the plasma membranes with other organelles. The traditional agarose affinity matrix is suitable for isolating proteins but has limitation in separating organelles due to the density of agarose. Immobilization of affinity ligands to magnetic beads allows separation of affinity matrix from organelles through magnets and could be developed for the isolation of organelles. We have developed a simple method for isolating plasma membranes using lectin concanavalin A (ConA) magnetic beads. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. The ConA magnetic beads are used to bind glycosylated proteins present in the membranes. The bound membranes are solubilized from the magnetic beads with a detergent containing the competing sugar alpha methyl mannoside. In this study, we describe the procedure of isolating rat liver plasma membranes using sucrose density gradient centrifugation as described by Neville. We then further purify the membrane fraction by using ConA magnetic beads. After this purification step, main liver plasma membrane proteins, especially the highly glycosylated ones and proteins containing transmembrane domains could be identified by LC-ESI-MS/MS. While not described here, the magnetic bead method can also be used to isolate plasma membranes from cell lysates. This membrane purification method should expedite the cataloging of plasma membrane proteome.

  18. Directing filtration to optimize enzyme immobilization in reactive membranes

    DEFF Research Database (Denmark)

    Luo, Jianquan; Marpani, Fauziah; Brites, Rita

    2014-01-01

    enzymatic reaction efficiency were evaluated in terms of enzyme loading, conversion rate and biocatalytic stability. Alcohol dehydrogenase (ADH) was selected as a model enzyme. Lower pressure, higher enzyme concentration and lower pH resulted in higher irreversible fouling resistance and lower permeate flux....... High pH during immobilization produced increased permeate flux but declines in conversion rates, likely because of the weak immobilization resulting from strong electrostatic repulsion between enzymes and membrane. The results showed that pore blocking as a fouling mechanism permitted a higher enzyme...... loading but generated more permeability loss, while cake layer formation increased enzyme stability but resulted in low loading rate. Low pH (near isoelectric point) favored hydrophobic and electrostatic adsorption of enzymes on the membrane, which reduced the enzyme stability. Neutral pH, however...

  19. Study on the preparation of immobilized glucose oxidase membrane and its application in clinic analysis

    International Nuclear Information System (INIS)

    Yu Ye; Cao Jin; Su Zongxian; Chen Zixiong

    1990-01-01

    The paper deals with the preparation of immobilized glucose oxidase membrane by using two steps irradiation (irradiation gratfting, irradiation entrapping). Some properties of membrane were discussed. The immobilized glucose oxidase membrane with oxygen electrode and oxygen analyser can be satisfied with the clinic analysis for the determination of serum glucose

  20. Enzyme immobilization by fouling in ultrafiltration membranes: Impact of membrane configuration and type on flux behavior and biocatalytic conversion efficacy

    DEFF Research Database (Denmark)

    Luo, Jianquan; Meyer, Anne S.; Jonsson, Gunnar Eigil

    2014-01-01

    Enzyme-immobilization in membranes accomplished by fostering membrane fouling was evaluated. Four different membrane configurations and five membranes were compared for immobilization of alcohol dehydrogenase (ADH) in terms of enzyme loading, permeate flux and final biocatalytic conversion...... and PLGC regenerated cellulose membranes. With these two highly hydrophilic membranes, the ADH enzyme activity was fully retained even after 24h of storage of the membrane. Filtration blocking and resistance models were used to analyze the fouling/immobilization mechanisms and give explanations...... for the different results. The work confirms that fouling-induced enzyme immobilization is a promising option for enhancing biocatalytic productivity, and highlights the significance of the membrane type and configuration for optimal performance....

  1. Immobilization of myoglobin in sodium alginate composite membranes

    Directory of Open Access Journals (Sweden)

    Katia Cecília de Souza Figueiredo

    2015-06-01

    Full Text Available AbstractThe immobilization of myoglobin in sodium alginate films was investigated with the aim of evaluating the protein stability in an ionic polymeric matrix. Myoglobin was chosen due to the resemblance to each hemoglobin tetramer. Sodium alginate, being a natural polysaccharide, was selected as the polymeric matrix because of its chemical structure and film-forming ability. To improve the mechanical resistance of sodium alginate films, the polymer was deposited over the surface of a cellulose acetate support by means of ultrafiltration. The ionic crosslink of sodium alginate was investigated by calcium ions. Composite membrane characterization comprised water swelling tests, water flux, SEM images and UV-visible spectroscopy. The electrostatic interaction between the protein and the polysaccharide did not damage the UV-visible pattern of native myoglobin. A good affinity between sodium alginate and cellulose acetate was observed. The top layer of the dense composite membrane successfully immobilized Myoglobin, retaining the native UV-visible pattern for two months.

  2. Graphene immobilized enzyme/polyethersulfone mixed matrix membrane: Enhanced antibacterial, permeable and mechanical properties

    International Nuclear Information System (INIS)

    Duan, Linlin; Wang, Yuanming; Zhang, Yatao; Liu, Jindun

    2015-01-01

    Graphical abstract: - Highlights: • Lysozyme was immobilized on the surface of graphene oxide (GO) and reduced GO (RGO). • The novel hybrid membranes based on lysozyme and graphene were fabricated firstly. • These membranes showed good antibacterial and mechanical performance. - Abstract: Enzyme immobilization has been developed to address lots of issues of free enzyme, such as instability, low activity and difficult to retain. In this study, graphene was used as an ideal carrier for lysozyme immobilization, including graphene oxide (GO) immobilized lysozyme (GO-Ly) and chemically reduced graphene oxide (CRGO) immobilized lysozyme (CRGO-Ly). Herein, lysozyme as a bio-antibacterial agent has excellent antibacterial performance and the products of its catalysis are safety and nontoxic. Then the immobilized lysozyme materials were blended into polyethersulfone (PES) casting solution to prepare PES ultrafiltration membrane via phase inversion method. GO and CRGO were characterized by Fourier transform infrared spectroscopy (FTIR), Ultraviolet–visible spectrum (UV), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and the immobilized lysozyme composites were observed by fluorescent microscopy. The results revealed that GO and CRGO were successfully synthesized and lysozyme was immobilized on their surfaces. The morphology, hydrophilicity, mechanical properties, separation properties and antibacterial activity of the hybrid membranes were characterized in detail. The hydrophilicity, water flux and mechanical strength of the hybrid membranes were significantly enhanced after adding the immobilized lysozyme. In the antibacterial experiment, the hybrid membranes exhibited an effective antibacterial performance against Escherichia coli (E. coli).

  3. The long-range organization of a native photosynthetic membrane

    NARCIS (Netherlands)

    Frese, Raoul N.; Siebert, C. Alistair; Niederman, Robert A.; Hunter, C. Neil; Otto, Cees; van Grondelle, Rienk

    2004-01-01

    Photosynthesis relies on the delicate interplay between a specific set of membrane-bound pigment–protein complexes that harvest and transport solar energy, execute charge separation, and conserve the energy. We have investigated the organization of the light-harvesting (LH) and reaction-center (RC)

  4. The long-range organization of a native photosynthetic membrane

    NARCIS (Netherlands)

    Frese, R.N.; Siebert, C.A.; Niederman, R.A.; Hunter, C.N.; Otto, C.; van Grondelle, R.

    2004-01-01

    Photosynthesis relies on the delicate interplay between a specific set of membrane-bound pigment-protein complexes that harvest and transport solar energy, execute charge separation, and conserve the energy. We have investigated the organization of the light-harvesting (LH) and reaction-center (RC)

  5. Transport dynamics in membranes of photosynthetic purple bacteria

    Science.gov (United States)

    Caycedo, Felipe; Rodriguez, Ferney; Quiroga, Luis; Fassioli, Francesca; Johnson, Neil

    2007-03-01

    Photo-Syntethic Unit (PSU) of purple bacteria is conformed by three basic constituents: Light Harvesting Complex 2 (LH2) antenna complexes, where chromophores are distributed in a ring in close contact with caroteniods with a function of collecting light; LH1s, ring shaped structures of chromophores which harvest and funnel excitations to the Reaction Centre (RC), where phtosynthesis takes place. Studies concerning a single PSU have been capable of reproducing experimental transfer times, but incapable of explaining the fact that architecture LH2-LH1-RC of phototosynthetic membranes changes as light intensity conditions vary. The organization of antenna complexes in the membranes that support PSU seems to have its own functionality. A hopping model where excitations are transferred within a membrane is used, and populations of RC, LH1 and LH2 are investigated. Different statistics concerning arrival times of excitations that excite a single PSU are considered and compared with the global model where coordinates of a great portion of a membrane are included. The model permits in a classical basis to understand which parameters make photosynthesis in purple bateria efficient and reliable.

  6. Energy transfer and clustering of photosynthetic light-harvesting complexes in reconstituted lipid membranes

    International Nuclear Information System (INIS)

    Dewa, Takehisa; Sumino, Ayumi; Watanabe, Natsuko; Noji, Tomoyasu; Nango, Mamoru

    2013-01-01

    Highlights: ► Photosynthetic light-harvesting complexes were reconstituted into lipid membranes. ► Energy transfers between light-harvesting complexes were examined. ► Atomic force microscopy indicated cluster formation of light-harvesting complexes. ► Efficient energy transfer was observed for the clustered complexes in the membranes. - Abstract: In purple photosynthetic bacteria, light-harvesting complex 2 (LH2) and light harvesting/reaction centre core complex (LH1-RC) play the key roles of capturing and transferring light energy and subsequent charge separation. These photosynthetic apparatuses form a supramolecular assembly; however, how the assembly influences the efficiency of energy conversion is not yet clear. We addressed this issue by evaluating the energy transfer in reconstituted photosynthetic protein complexes LH2 and LH1-RC and studying the structures and the membrane environment of the LH2/LH1-RC assemblies, which had been embedded into various lipid bilayers. Thus, LH2 and LH1-RC from Rhodopseudomonas palustris 2.1.6 were reconstituted in phosphatidylglycerol (PG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE)/PG/cardiolipin (CL). Efficient energy transfer from LH2 to LH1-RC was observed in the PC and PE/PG/CL membranes. Atomic force microscopy revealed that LH2 and LH1-RC were heterogeneously distributed to form clusters in the PC and PE/PG/CL membranes. The results indicated that the phospholipid species influenced the cluster formation of LH2 and LH1-RC as well as the energy transfer efficiency

  7. Energy transfer and clustering of photosynthetic light-harvesting complexes in reconstituted lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dewa, Takehisa, E-mail: takedewa@nitech.ac.jp [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Japan Science and Technology, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012 (Japan); Sumino, Ayumi; Watanabe, Natsuko; Noji, Tomoyasu [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nango, Mamoru, E-mail: nango@nitech.ac.jp [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2013-06-20

    Highlights: ► Photosynthetic light-harvesting complexes were reconstituted into lipid membranes. ► Energy transfers between light-harvesting complexes were examined. ► Atomic force microscopy indicated cluster formation of light-harvesting complexes. ► Efficient energy transfer was observed for the clustered complexes in the membranes. - Abstract: In purple photosynthetic bacteria, light-harvesting complex 2 (LH2) and light harvesting/reaction centre core complex (LH1-RC) play the key roles of capturing and transferring light energy and subsequent charge separation. These photosynthetic apparatuses form a supramolecular assembly; however, how the assembly influences the efficiency of energy conversion is not yet clear. We addressed this issue by evaluating the energy transfer in reconstituted photosynthetic protein complexes LH2 and LH1-RC and studying the structures and the membrane environment of the LH2/LH1-RC assemblies, which had been embedded into various lipid bilayers. Thus, LH2 and LH1-RC from Rhodopseudomonas palustris 2.1.6 were reconstituted in phosphatidylglycerol (PG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE)/PG/cardiolipin (CL). Efficient energy transfer from LH2 to LH1-RC was observed in the PC and PE/PG/CL membranes. Atomic force microscopy revealed that LH2 and LH1-RC were heterogeneously distributed to form clusters in the PC and PE/PG/CL membranes. The results indicated that the phospholipid species influenced the cluster formation of LH2 and LH1-RC as well as the energy transfer efficiency.

  8. Enhanced starch hydrolysis using α-amylase immobilized on cellulose ultrafiltration affinity membrane.

    Science.gov (United States)

    Konovalova, Viktoriia; Guzikevich, Kateryna; Burban, Anatoliy; Kujawski, Wojciech; Jarzynka, Karolina; Kujawa, Joanna

    2016-11-05

    In order to prepare ultrafiltration membranes possessing biocatalytic properties, α-amylase has been immobilized on cellulose membranes. Enzyme immobilization was based on a covalent bonding between chitosan and a surface of cellulose membrane, followed by an attachment of Cibacron Blue F3G-A dye as affinity ligand. Various factors affecting the immobilization process, such as enzyme concentration, pH of modifying solution, zeta-potential of membrane surface, and stability of immobilized enzyme were studied. The applicability of immobilized α-amylase has been investigated in ultrafiltration processes. The immobilization of α-amylase on membrane surface allows to increase the value of mass transfer coefficient and to decrease the concentration polarization effect during ultrafiltration of starch solutions. The enzyme layer on the membrane surface prevents a rapid increase of starch concentration due to the amylase hydrolysis of starch in the boundary layer. The presented affinity immobilization technique allows also for the regeneration of membranes from inactivated enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Photoproduction of hydrogen by membranes of green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, J D; Olson, J M

    1980-01-01

    Photoproduction of H/sub 2/ from ascorbate by unit-membrane vesicles from Chlorobium limicola f. thiosulfatophilum was achieved with a system containing gramicidin D, tetramethyl-p-phenylenediamine, methyl viologen, dithioerythritol, Clostridium hydrogenase, and an oxygen-scavenging mixture of glucose, glucose oxidase, ethanol, and catalase. Maximum quantum yield was less than one percent. Half maximum rate of H/sub 2/ production occurred at a white-light intensity of approximately 0.15 cm/sup -2/. The reaction was inhibited completely by 0.3% sodium dodecylbenzene sulfonate, 1% Triton X-100, or preheating the vesicles at 100/sup 0/C for 5 minutes. Low concentrations (0.01 and 0.05%) of Triton X-100 about doubled the reaction rate.

  10. Interface for Light-Driven Electron Transfer by Photosynthetic Complexes Across Block Copolymer Membranes.

    Science.gov (United States)

    Kuang, Liangju; Olson, Tien L; Lin, Su; Flores, Marco; Jiang, Yunjiang; Zheng, Wan; Williams, JoAnn C; Allen, James P; Liang, Hongjun

    2014-03-06

    Incorporation of membrane proteins into nanodevices to mediate recognition and transport in a collective and scalable fashion remains a challenging problem. We demonstrate how nanoscale photovoltaics could be designed using robust synthetic nanomembranes with incorporated photosynthetic reaction centers (RCs). Specifically, RCs from Rhodobacter sphaeroides are reconstituted spontaneously into rationally designed polybutadiene membranes to form hierarchically organized proteopolymer membrane arrays via a charge-interaction-directed reconstitution mechanism. Once incorporated, the RCs are fully active for prolonged periods based upon a variety of spectroscopic measurements, underscoring preservation of their 3D pigment configuration critical for light-driven charge transfer. This result provides a strategy to construct solar conversion devices using structurally versatile proteopolymer membranes with integrated RC functions to harvest broad regions of the solar spectrum.

  11. Energy transfer dynamics in an RC-LH1-PufX tubular photosynthetic membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, J; Sener, M; Schulten, K [Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana (United States); Struempfer, J [Center for Biophysics and Computational Biology and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana (United States); Qian, P; Hunter, C N, E-mail: kschulte@ks.uiuc.ed [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom)

    2010-08-15

    Light absorption and the subsequent transfer of excitation energy are the first two steps in the photosynthetic process, carried out by protein-bound pigments, mainly bacteriochlorophylls (BChls), in photosynthetic bacteria. BChls are anchored in light-harvesting (LH) complexes, such as light-harvesting complex I (LH1), which directly associates with the reaction center (RC), forming the RC-LH1 core complex. In Rhodobacter sphaeroides, RC-LH1 core complexes contain an additional protein, PufX, and assemble into dimeric RC-LH1-PufX core complexes. In the absence of LH complex II (LH2), the former complexes can aggregate into a helically ordered tubular photosynthetic membrane. We have examined the excitation transfer dynamics in a single RC-LH1-PufX core complex dimer using the hierarchical equations of motion for dissipative quantum dynamics that accurately, yet in a computationally costly manner, treat the coupling between BChls and their protein environment. A widely employed description, the generalized Foerster (GF) theory, was also used to calculate the transfer rates of the same excitonic system in order to verify the accuracy of this computationally cheap method. Additionally, in light of the structural uncertainties in the Rba. sphaeroides RC-LH1-PufX core complex, geometrical alterations were introduced into the BChl organization. It is shown that the energy transfer dynamics are not affected by the considered changes in the BChl organization and that the GF theory provides accurate transfer rates. An all-atom model for a tubular photosynthetic membrane is then constructed on the basis of electron microscopy data, and the overall energy transfer properties of this membrane are computed.

  12. Energy transfer dynamics in an RC-LH1-PufX tubular photosynthetic membrane

    International Nuclear Information System (INIS)

    Hsin, J; Sener, M; Schulten, K; Struempfer, J; Qian, P; Hunter, C N

    2010-01-01

    Light absorption and the subsequent transfer of excitation energy are the first two steps in the photosynthetic process, carried out by protein-bound pigments, mainly bacteriochlorophylls (BChls), in photosynthetic bacteria. BChls are anchored in light-harvesting (LH) complexes, such as light-harvesting complex I (LH1), which directly associates with the reaction center (RC), forming the RC-LH1 core complex. In Rhodobacter sphaeroides, RC-LH1 core complexes contain an additional protein, PufX, and assemble into dimeric RC-LH1-PufX core complexes. In the absence of LH complex II (LH2), the former complexes can aggregate into a helically ordered tubular photosynthetic membrane. We have examined the excitation transfer dynamics in a single RC-LH1-PufX core complex dimer using the hierarchical equations of motion for dissipative quantum dynamics that accurately, yet in a computationally costly manner, treat the coupling between BChls and their protein environment. A widely employed description, the generalized Foerster (GF) theory, was also used to calculate the transfer rates of the same excitonic system in order to verify the accuracy of this computationally cheap method. Additionally, in light of the structural uncertainties in the Rba. sphaeroides RC-LH1-PufX core complex, geometrical alterations were introduced into the BChl organization. It is shown that the energy transfer dynamics are not affected by the considered changes in the BChl organization and that the GF theory provides accurate transfer rates. An all-atom model for a tubular photosynthetic membrane is then constructed on the basis of electron microscopy data, and the overall energy transfer properties of this membrane are computed.

  13. Separations using biological carriers immobilized in porous polymeric and sol-gel template synthesized nanotubular membranes

    Science.gov (United States)

    Lakshmi, Brinda B.

    1998-12-01

    The overall goal of the dissertation was to use immobilized biological carriers in membranes to separate compounds as challenging as enantiomers. The membranes were prepared by a process called 'template synthesis'. Template synthesis has been used to synthesize semiconductor nanostructures and also membranes which do the enantioseparation by a process called facilitated transport. The immobilized proteins act as carriers facilitating the transport of the substrate molecules through the membrane. The apoenzymes are enzymes devoid of cofactor. Apoenzymes will possess the molecular recognition site for the substrate but will not catalyze the reaction. Apoenzymes immobilized in the pores of porous polycarbonate membrane was used as a carrier. The ends of the pores were closed with porous polypyrrole. Compounds as interesting as enantiomers were separated with these membranes. Template synthesis has been extended to the synthesis of many important semiconductor oxide naostructures like TiO2, SiO2, ZnO, Co3O4 and MnO2. These structures were made by dipping the alumina template membrane in the sol and heating. Ti0 2 tubules and fibers were obtained by this method. The fibers were used to study photocatalysis reaction of organic compounds in sunlight. Proteins were immobilized within the inner surface of the tubules using Sn chemistry. Bovine serum albumn (BSA) immobilized within the different diameter tubules showed varying degree of facilitation with phenylalanine. The membranes also show interesting switching of selectivity from L to D depending on the tube size and feed concentration.

  14. The study of preparation for immobilized cells membranes of E. Coli. by radiation technique

    International Nuclear Information System (INIS)

    Cao Jin; Chen Pin; Yu Yi

    1991-01-01

    The paper described the preparation of immobilized cells membranes with E. Coli by radiation technique. The nylon 6 was grafted with HEMA, which as a matrix to prepare immobilized cells membranes with E. Coli. by radiation entrapment at low temperature. The results showed that the retentive activity possessed a maximum value for membranes with E. Coli. when the irradiation dose was at 10-12 kGy, the entrapped cells has 2.3 g/ml at 50% HEMA concentration, the optimum pH and optimum temperature for membranes with E. Coli. are as same the original cells

  15. Immobilization of β-galactosidase from Kluyveromyces lactis onto polymeric membrane surfaces: effect of surface characteristics.

    Science.gov (United States)

    Güleç, Hacı Ali

    2013-04-01

    The aim of this study was to investigate the effects of surface characteristics of plain and plasma modified cellulose acetate (CA) membranes on the immobilization yield of β-galactosidases from Kluyveromyces lactis (KLG) and its galacto-oligosaccharide (GOS) yield, respectively. Low pressure plasma treatments involving oxygen plasma activation, plasma polymerization (PlsP) of ethylenediamine (EDA) and PlsP of 2-mercaptoethanol were used to modify plain CA membrane surfaces. KLG enzyme was immobilized onto plain and oxygen plasma treated membrane surfaces by simple adsorption. Oxygen plasma activation increased the hydrophylicity of CA membrane surfaces and it improved the immobilization yield of the enzyme by 42%. KLG enzyme was also immobilized onto CA membrane surfaces through amino groups created by PlsP of EDA via covalent binding. Plasma action at 60W plasma power and 15 min. exposure time improved the amount of membrane bounded enzyme by 3.5-fold. The enrichment of the amount of amino groups via polyethyleneimine (PEI) addition enhanced this increase from 3.5-fold to 4.5-fold. Although high enzyme loading was achived (65-83%), both of the methods dramatically decreased the enzyme activity (11-12%) and GOS yield due to probably negative effects of active amino groups. KLG enzyme was more effectively immobilized onto thiolated CA membrane surface created by PlsP of 2-mercaptoethanol with high immobilization yield (70%) and especially high enzyme activity (46%). Immobilized enzymes on the CA membranes treated by PlsP were successively reutilized for 5-8 cycles at 25°C and enzymatic derivatives retained approximately 75-80% of their initial activites at the end of the reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Energy transfer in light-adapted photosynthetic membranes: from active to saturated photosynthesis.

    Science.gov (United States)

    Fassioli, Francesca; Olaya-Castro, Alexandra; Scheuring, Simon; Sturgis, James N; Johnson, Neil F

    2009-11-04

    In bacterial photosynthesis light-harvesting complexes, LH2 and LH1 absorb sunlight energy and deliver it to reaction centers (RCs) with extraordinarily high efficiency. Submolecular resolution images have revealed that both the LH2:LH1 ratio, and the architecture of the photosynthetic membrane itself, adapt to light intensity. We investigate the functional implications of structural adaptations in the energy transfer performance in natural in vivo low- and high-light-adapted membrane architectures of Rhodospirillum photometricum. A model is presented to describe excitation migration across the full range of light intensities that cover states from active photosynthesis, where all RCs are available for charge separation, to saturated photosynthesis where all RCs are unavailable. Our study outlines three key findings. First, there is a critical light-energy density, below which the low-light adapted membrane is more efficient at absorbing photons and generating a charge separation at RCs, than the high-light-adapted membrane. Second, connectivity of core complexes is similar in both membranes, suggesting that, despite different growth conditions, a preferred transfer pathway is through core-core contacts. Third, there may be minimal subareas on the membrane which, containing the same LH2:LH1 ratio, behave as minimal functional units as far as excitation transfer efficiency is concerned.

  17. Photosynthetic solar cell using nanostructured proton exchange membrane for microbial biofilm prevention.

    Science.gov (United States)

    Lee, Dong Hyun; Oh, Hwa Jin; Bai, Seoung Jae; Song, Young Seok

    2014-06-24

    Unwanted biofilm formation has a detrimental effect on bioelectrical energy harvesting in microbial cells. This issue still needs to be solved for higher power and longer durability and could be resolved with the help of nanoengineering in designing and manufacturing. Here, we demonstrate a photosynthetic solar cell (PSC) that contains a nanostructure to prevent the formation of biofilm by micro-organisms. Nanostructures were fabricated using nanoimprint lithography, where a film heater array system was introduced to precisely control the local wall temperature. To understand the heat and mass transfer phenomena behind the manufacturing and energy harvesting processes of PSC, we carried out a numerical simulation and experimental measurements. It revealed that the nanostructures developed on the proton exchange membrane enable PSC to produce enhanced output power due to the retarded microbial attachment on the Nafion membrane. We anticipate that this strategy can provide a pathway where PSC can ensure more renewable, sustainable, and efficient energy harvesting performance.

  18. Triclosan-immobilized polyamide thin film composite membranes with enhanced biofouling resistance

    Science.gov (United States)

    Park, Sang-Hee; Hwang, Seon Oh; Kim, Taek-Seung; Cho, Arah; Kwon, Soon Jin; Kim, Kyoung Taek; Park, Hee-Deung; Lee, Jung-Hyun

    2018-06-01

    We report on a strategy to improve biofouling resistance of a polyamide (PA) thin-film composite (TFC) reverse osmosis (RO) membrane via chemically immobilizing triclosan (TC), known as a common organic biocide, on its surface. To facilitate covalent attachment of TC on the membrane surface, TC was functionalized with amine moiety to prepare aminopropyl TC. Then, the TC-immobilized TFC (TFC-TC) membranes were fabricated through a one-step amide formation reaction between amine groups of aminopropyl TC and acyl chloride groups present on the PA membrane surface, which was confirmed by high-resolution XPS. Strong stability of the immobilized TC was also confirmed by a hydraulic washing test. Although the TFC-TC membrane showed slightly reduced separation performance compared to the pristine control, it still maintained a satisfactory RO performance level. Importantly, the TFC-TC membrane exhibited excellent antibacterial activity against both gram negative (E. coli and P. aeruginosa) and gram positive (S. aureus) bacteria along with greatly enhanced resistance to biofilm formation. Our immobilization approach offers a robust and relatively benign strategy to control biofouling of functional surfaces, films and membranes.

  19. Efficient protein immobilization on polyethersolfone electrospun nanofibrous membrane via covalent binding for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudifard, Matin [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Soudi, Sara [Stem Cell Biology Department, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Soleimani, Masoud [Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hosseinzadeh, Simzar [Nanotechnology and Tissue Engineering Department, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Esmaeili, Elaheh [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Vossoughi, Manouchehr, E-mail: vosoughi@sharif.edu [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2016-01-01

    In this paper we introduce novel strategy for antibody immobilization using high surface area electrospun nanofibrous membrane based on ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling chemistry. To present the high performance of proposed biosensors, anti-staphylococcus enterotoxin B (anti-SEB) was used as a model to demonstrate the utility of our proposed system. Polymer solution of polyethersolfone was used to fabricate fine nanofibrous membrane. Moreover, industrial polyvinylidene fluoride membrane and conventional microtiter plate were also used to compare the efficiency of antibody immobilization. Scanning electron microscopy images were taken to study the morphology of the membranes. The surface activation of nanofibrous membrane was done with the help of O{sub 2} plasma. PES nanofibrous membrane with carboxyl functional groups for covalent attachment of antibodies were treated by EDC/NHS coupling agent. The quantity of antibody immobilization was measured by enzyme-linked immuno sorbent assay (ELISA) method. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy was performed to confirm the covalent immobilization of antibody on membrane. Atomic force microscopy, scanning electron microscopy and invert fluorescence microscopy were used to analyze the antibody distribution pattern on solid surfaces. Results show that oxygen plasma treatment effectively increased the amount of antibody immobilization through EDC/NHS coupling chemistry. It was found that the use of nanofibrous membrane causes the improved detection signal of ELISA based biosensors in comparison to the standard assay carried out in the 96-well microtiter plate. This method has the potential to improve the ELISA-based biosensor and we believe that this technique can be used in various biosensing methods. - Highlights: • Introduction of novel strategy for antibody immobilization using high surface area electrospun

  20. Multienzyme Immobilized Polymeric Membrane Reactor for the Transformation of a Lignin Model Compound

    Directory of Open Access Journals (Sweden)

    Rupam Sarma

    2018-04-01

    Full Text Available We have developed an integrated, multienzyme functionalized membrane reactor for bioconversion of a lignin model compound involving enzymatic catalysis. The membrane bioreactors were fabricated through the layer-by-layer assembly approach to immobilize three different enzymes (glucose oxidase, peroxidase and laccase into pH-responsive membranes. This novel membrane reactor couples the in situ generation of hydrogen peroxide (by glucose oxidase to oxidative conversion of a lignin model compound, guaiacylglycerol-β-guaiacyl ether (GGE. Preliminary investigation of the efficacy of these functional membranes towards GGE degradation is demonstrated under convective flow mode. Over 90% of the initial feed could be degraded with the multienzyme immobilized membranes at a residence time of approximately 22 s. GGE conversion product analysis revealed the formation of oligomeric oxidation products upon reaction with peroxidase, which may be a potential hazard to membrane bioreactors. These oxidation products could further be degraded by laccase enzymes in the multienzymatic membranes, explaining the potential of multi enzyme membrane reactors. The multienzyme incorporated membrane reactors were active for more than 30 days of storage time at 4 °C. During this time span, repetitive use of the membrane reactor was demonstrated involving 5–6 h of operation time for each cycle. The membrane reactor displayed encouraging performance, losing only 12% of its initial activity after multiple cycles of operation.

  1. Plasma modified PLA electrospun membranes for actinorhodin production intensification in Streptomyces coelicolor immobilized-cell cultivations.

    Science.gov (United States)

    Scaffaro, Roberto; Lopresti, Francesco; Sutera, Alberto; Botta, Luigi; Fontana, Rosa Maria; Gallo, Giuseppe

    2017-09-01

    Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomycete submerged cultivations, thus, resulting in an improved biosynthetic capability. In this work, electrospun polylactic acid (PLA) membranes, subjected or not to O 2 -plasma treatment (PLA-plasma), were used as support for immobilized-cell submerged cultivations of Streptomyces coelicolor M145. This strain produces different bioactive compounds, including the blue-pigmented actinorhodin (ACT) and red-pigmented undecylprodigiosin (RED), and constitutes a model for the study of antibiotic-producing actinomycetes. Wet contact angles and X-ray photoelectron spectroscopy analysis confirmed the increased wettability of PLA-plasma due to the formation of polar functional groups such as carboxyl and hydroxyl moieties. Scanning electron microscope observations, carried out at different incubation times, revealed that S. coelicolor immobilized-cells created a dense "biofilm-like" mycelial network on both kinds of PLA membranes. Cultures of S. coelicolor immobilized-cells on PLA or PLA-plasma membranes produced higher biomass (between 1.5 and 2 fold) as well as higher levels of RED and ACT than planktonic cultures. In particular, cultures of immobilized-cells on PLA and PLA-plasma produced comparable levels of RED that were approximatively 4 and 5 fold higher than those produced by planktonic cultures, respectively. In contrast, levels of ACT produced by immobilized-cell cultures on PLA and PLA-plasma were different, being 5 and 10 fold higher than those of planktonic cultures, respectively. Therefore, this is study demonstrated the positive influence of PLA membrane on growth and secondary metabolite production in S. coelicolor and also revealed that O 2 -plasma treated PLA membranes

  2. One-step isolation of plasma membrane proteins using magnetic beads with immobilized concanavalin A

    DEFF Research Database (Denmark)

    Lee, Yu-Chen; Block, Gregory; Chen, Huiwen

    2008-01-01

    We have developed a simple method for isolating and purifying plasma membrane proteins from various cell types. This one-step affinity-chromatography method uses the property of the lectin concanavalin A (ConA) and the technique of magnetic bead separation to obtain highly purified plasma membrane...... proteins from crude membrane preparations or cell lines. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. When these ConA magnetic beads were used to enrich plasma membranes from a crude membrane preparation, this procedure resulted in 3.7-fold enrichment...... of plasma membrane marker 5'-nucleotidase activity with 70% recovery of the activity in the crude membrane fraction of rat liver. In agreement with the results of 5'-nucleotidase activity, immunoblotting with antibodies specific for a rat liver plasma membrane protein, CEACAM1, indicated that CEACAM1...

  3. Cellulose acetate membranes functionalized with resveratrol by covalent immobilization for improved osseointegration

    Science.gov (United States)

    Pandele, A. M.; Neacsu, P.; Cimpean, A.; Staras, A. I.; Miculescu, F.; Iordache, A.; Voicu, S. I.; Thakur, V. K.; Toader, O. D.

    2018-04-01

    Covalent immobilization of resveratrol onto cellulose acetate polymeric membranes used as coating on a Mg-1Ca-0.2Mn-0.6Zr alloy is presented for potential application in the improvement of osseointegration processes. For this purpose, cellulose acetate membrane is hydrolysed in the presence of potassium hydroxide, followed by covalent immobilization of aminopropyl triethoxy silane. Resveratrol was immobilized onto membranes using glutaraldehyde as linker. The newly synthesised functional membranes were thoroughly characterized for their structural characteristics determination employing X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FT-IR), Raman spectroscopy, thermogravimetric analysis (TGA/DTG) and scanning electron microscopy (SEM) techniques. Subsequently, in vitro cellular tests were performed for evaluating the cytotoxicity biocompatibility of synthesized materials and also the osseointegration potential of obtained derivatised membrane material. It was demonstrated that both polymeric membranes support viability and proliferation of the pre-osteoblastic MC3T3-E1 cells, thus providing a good protection against the potential harmful effects of the compounds released from coated alloys. Furthermore, cellulose acetate membrane functionalized with resveratrol exhibits a significant increase in alkaline phosphatase activity and extracellular matrix mineralization, suggesting its suitability to function as an implant surface coating for guided bone regeneration.

  4. Covalent Immobilization of Peroxidase onto Hybrid Membranes for the Construction of Optical Biosensor

    Directory of Open Access Journals (Sweden)

    Lyubov Yotova

    2015-06-01

    Full Text Available The aim of this study is to covalently immobilize horse radish peroxidase (HRP onto new hybrid membranes synthesized by the sol-gel method based on silica precursors, dendrimers and cellulose derivatives. This new system will be used for designing biosensor. For investigation of the properties of membranes, HRP was used as a modeling enzyme. Kinetic parameters, pH and temperature optimum were determined, and the structure of the membranes surface was examined. Results showed higher relative and residual activity of HRP immobilized onto membranes with cellulose acetate butyrate with high molecular weight CAB/H. This novel biosensor could offer a simple, cheap and rapid tool with enhanced sensing performance as well as having potentials to find application in medicine, pharmacy, food and process control and environmental monitoring.

  5. Oxadiazole telechelics immobilized on silica for proton conductive membranes

    Energy Technology Data Exchange (ETDEWEB)

    Treekamol, Yaowapa; Schieda, Mauricio [GKSS-Forschungszentrum Geesthacht GmbH (Germany); Nunes, Suzana [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Schulte, Karl [Technische Univ. Hamburg-Harburg, Hamburg (Germany)

    2010-07-01

    Functionalized silica and layered silicates have been used in our group to prepare proton conductive membranes with applications to direct methanol fuel cells. We report recent results on the use of silica with amphoteric functionalization in proton conductive membranes working at low humidity levels. Aerosil silica was functionalized by reacting it subsequently with bromophenyltrimethoxysilane and with aromatic bishydroxy terminated oxadiazole oligomers. We have prepared proton conductive membranes including as fillers a series of different sulfonated and non-sulfonated telechelics, synthesized with diphenylsulfone, diphenylether and fluorinated oxadiazole segments. We will present a comparison between fillers with different functionalization and how they affect the conductivity of a proton conductive polymer matrix. The functionalized fillers present the possibility of improving water retention and increasing the maximum doping level with phosphoric acid. Furthermore, the oligomer segments, containing both basic nitrogen and acid sulfonic groups, give an amphoteric character to the membrane, improving the proton conductivity in low humidity conditions. (orig.)

  6. Antimicrobial membrane surfaces via efficient polyethyleneimine immobilization and cationization

    Science.gov (United States)

    Qiu, Wen-Ze; Zhao, Zi-Shu; Du, Yong; Hu, Meng-Xin; Xu, Zhi-Kang

    2017-12-01

    Biofouling control is a major task in membrane separation processes for water treatment and biomedical applications. In this work, N-alkylated polyethylenimine (PEI) is facilely and efficiently introduced onto the membrane surfaces via the co-deposition of catechol (CCh) and PEI, followed by further grafting of PEIs (600 Da, 70 kDa and 750 kDa) and cationization with methyl iodide (CH3I). The physical and chemical properties of the constructed membrane surfaces are characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential and water contact angle measurements. Antibacterial assay reveals that the optimized membrane surfaces possess around 95% antibacterial efficiency against Gram-positive Staphylococcus aureus (S. aureus) with weak adhesion of bacteria cells after 24 h of bacterial contact. Additionally, the membrane surfaces also exhibit much enhanced antifouling property during the filtration of opposite charged bovine serum albumin (BSA). These results demonstrate a useful strategy for the surface modification of separation membranes by a kind of antimicrobial and antifouling coating.

  7. Eggshell membrane: A natural substrate for immobilization and detection of DNA

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Preetam Guha; Roy, Somenath, E-mail: sroy@cgcri.res.in

    2016-02-01

    Chemically modified eggshell membranes (ESM) have been explored as potentially novel platforms for immobilization of oligonucleotides and subsequent detection of target DNA. The fibrous network of the native ESM as well those functionalized with acetic acid or n-butyl acetate has been examined by field-emission scanning electron microscopy (FESEM). The formation of surface functional moieties has been confirmed by Fourier-transform infrared spectroscopy (FTIR). DNA molecules, with an end terminal − NH{sub 2} group (at 5′ end) have been immobilized on the chemically modified ESM surface. The effect of surface modification on the DNA immobilization efficiency has been investigated using fluorescence microscopy and atomic force microscopy (AFM). The above studies concurrently suggest that functionalization of ESM with n-butyl acetate causes a better homogeneity of the DNA probes on the membrane surface. On-chip hybridization of the target DNA with the surface bound capture probes has been performed on the functionalized membranes. It is observed that n-butyl acetate modification of ESM pushes the limit of detection (LOD) of the DNA sensors by at least an order of magnitude compared to the other modification method. - Graphical abstract: Eggshell membranes (ESM) have been chemically modified with acetic acid or n-butyl acetate for immobilization of aminated capture probes and subsequent detection of fluorophore-tagged target DNA molecules. n-Butyl acetate modified ESM exhibits superior homogeneity of capture probe immobilization and lower limit of detection for the target DNA molecules. - Highlights: • Eggshell membranes (ESM) have been explored as potentially novel platforms for immobilization of oligonucleotides. • Compared to native ESM, those modified with acetic acid or n-butyl acetate have shown more efficient loading of DNA probes. • ESM modified with n-butyl acetate pushed the lower limit of detection (LOD) of the sensor down to 10 nM of target DNA

  8. CO2-Switchable Membranes Prepared by Immobilization of CO2-Breathing Microgels.

    Science.gov (United States)

    Zhang, Qi; Wang, Zhenwu; Lei, Lei; Tang, Jun; Wang, Jianli; Zhu, Shiping

    2017-12-20

    Herein, we report the development of a novel CO 2 -responsive membrane system through immobilization of CO 2 -responsive microgels into commercially available microfiltration membranes using a method of dynamic adsorption. The microgels, prepared from soap-free emulsion polymerization of CO 2 -responsive monomer 2-(diethylamino)ethyl methacrylate (DEA), can be reversibly expanded and shrunken upon CO 2 /N 2 alternation. When incorporated into the membranes, this switching behavior was preserved and further led to transformation between microfiltration and ultrafiltration membranes, as indicated from the dramatic changes on water flux and BSA rejection results. This CO 2 -regulated performance switching of membranes was caused by the changes of water transportation channel, as revealed from the dynamic water contact angle tests and SEM observation. This work represents a simple yet versatile strategy for making CO 2 -responsive membranes.

  9. Dependence of protein binding capacity of dimethylamino-γ-butyric-acid (DMGABA)-immobilized porous membrane on composition of solvent used for DMGABA immobilization

    International Nuclear Information System (INIS)

    Iwanade, Akio; Umeno, Daisuke; Saito, Kyoichi; Sugo, Takanobu

    2013-01-01

    Dimethylamino-γ-butyric acid (DMGABA) as an ampholite was reacted with the epoxy group of the poly-glycidyl methacrylate chain grafted onto the pore surface of a porous hollow-fiber polyethylene membrane by radiation-induced graft polymerization. DMGABA was dissolved in a mixture of dioxane and water at various dioxane volume fractions, defined by dividing the dioxane volume by the total volume. The equilibrium binding capacity (EBC) of the DMGABA-immobilized porous hollow-fiber membrane for lysozyme was evaluated in the permeation mode. The EBC was varied from a 1/50-fold monolayer binding capacity to a 10-fold monolayer binding capacity by controlling the composition of the solvent used for DMGABA immobilization and the molar conversion of the epoxy group into the DMGABA group. - Highlights: ► A DMGABA membrane was immobilized by irradiation induced graft polymerization. ► The DMGABA was immobilized in a mixture of dioxane and water of various compositions. ► Lysozyme adsorptivity of DMGABA-immobilized membranes evaluated in the permeation mode. ► The composition of the DMGABA immobilized solvent can control adsorptivity

  10. Comparative study between yeasts immobilized on alumina beads and on membranes prepared by two routes

    Directory of Open Access Journals (Sweden)

    Kiyohara Pedro K.

    2003-01-01

    Full Text Available Alumina channeled beads and rough surface membranes prepared from aqueous sols of fibrillar pseudoboehmite are able to immobilize yeasts for ethanol fermentation of sugar solutions. This paper describes comparative results of assays carried out with yeasts immobilized onto alpha-alumina beads and membranes prepared under two different conditions of processing and firing. The fermentation tests evaluated by the decrease of fermentable sugars, referred as Brix degrees per hour, indicated that the yeasts immobilized on beads had similar performance, probably because their surfaces, even being morphologically different, presented the same value of open porosity. One type of membrane (asymmetrical; precursor: pseudoboehmite; firing temperature 1,150ºC; crystal structure; alpha-alumina had better performance than the other type (asymmetrical; precursor: fibrillar pseudoboehmite plus aluminum hydroxiacetate mixture; 1,150ºC; alpha-alumina because the yeast cells entered into their porous interior through the surface slits, were immobilized and their growth was easier than on the external surface.

  11. Immobilization of alcohol dehydrogenase on ceramic silicon carbide membranes for enzymatic CH3 OH production

    DEFF Research Database (Denmark)

    Zeuner, Birgitte; Ma, Nicolaj; Berendt, Kasper

    2018-01-01

    BACKGROUND Alcohol dehydrogenase (ADH; EC 1.1.1.1) catalyzes oxidation of CH3OH to CHOH during NAD+ reduction to NADH. ADH can also accelerate the reverse reaction, which is studied as part of cascadic enzymatic conversion of CO2 to CH3OH. In the present study, immobilization of ADH onto macropor......BACKGROUND Alcohol dehydrogenase (ADH; EC 1.1.1.1) catalyzes oxidation of CH3OH to CHOH during NAD+ reduction to NADH. ADH can also accelerate the reverse reaction, which is studied as part of cascadic enzymatic conversion of CO2 to CH3OH. In the present study, immobilization of ADH onto......‐of‐concept for the use of NaOH‐treated SiC membranes for covalent enzyme immobilization and biocatalytic efficiency improvement of ADH during multiple reaction cycles. These data have implications for the development of robust extended enzymatic reactions....

  12. Biochemical factors affecting the quantum efficiency of hydrogen production by membranes of green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, J.D.; Olson, J.M.

    1981-01-01

    Photohydrogen production, 200-700 ..mu..mol H/sub 2/ h/sup -1/ (mg bacteriochlorophyll a)/sup -1/ has been obtained in a system containing unit membrane vesicles (Complex I) from the green photosynthetic bacterium Chlorobium limicola f. thiosulfatophilum, ascorbate, N,N,N',N'-tetramethyl-p-phenylenediamine, dithioerythritol, an oxygen scavenging mixture, either methyl viologen (MV) or clostridial ferredoxin (CPS Fd) as electron carrier, and either CPS hydrogenase or platinum asbestos as catalyst. All components are necessary for maximum activity, and spinach Fd cannot be substituted for CPS Fd. Higher rates of photohydrogen production are obtained using MV or CPS Fd with hydrogenase than with MV and Pt asbestos. The highest quantum efficiencies (7-10% at 0.2-0.9 mW absorbed light and over 20% at lower light) were obtained with CPS Fd, hydrogenase and non-saturating 812 nm light. With saturating white light, however, rates of photohydrogen production varied relatively little among the various combinations of electron carrier and catalyst tested. The reaction rate is unaffected by 0.03% Triton X-100, and is insensitive to treatment with antimycin a or m-chloro-carbonyl cyanide phenylhydrazone.This indicates that neither electron flow through an endogenous cyclic chain, nor maintenance of a proton gradient are involved in this process.

  13. Optical Biosensor with Multienzyme System Immobilized onto Hybrid Membrane for Pesticides Determination

    Directory of Open Access Journals (Sweden)

    Lyubov Yotova

    2011-12-01

    Full Text Available A construction of optical biosensor based on simultaneous immobilization of acetylcholinesterase and choline oxidase enzymes for the detection of pesticides residues is described. Different kinds of novel SiO2 hybrid membranes were synthesized to be suitable for optical biosensors using sol-gel techniques. The bioactive component of the sensor consists of a multi-enzyme system including acetylcholinesterase and choline oxidase covalently immobilized on new hybrid membranes. The sensor exhibited a linear response to acetylcholine in a concentration range of 2.5 - 30 mM. Inhibition plots obtained from testing carbamate (carbofuran pesticides exhibited concentration dependent behaviour and showed linear profiles in concentration ranges between 5x10-8 - 5x10-7 M for carbofuran. The factors affecting the constructed optical biosensors were investigated.

  14. Surface Modification of Polypropylene Microporous Membrane by Atmospheric-Pressure Plasma Immobilization of N,N-dimethylamino Ethyl Methacrylate

    International Nuclear Information System (INIS)

    Zhong Shaofeng

    2010-01-01

    Surface modification of polypropylene microporous membrane (PPMM) was performed by atmospheric pressure dielectric barrier discharge plasma immobilization of N,N-dimethylamino ethyl methacrylate (DMAEMA). Structural and morphological changes on the membrane surface were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscopy (FE-SEM). Water contact angles of the membrane surfaces were also measured by the sessile drop method. Results reveal that both the plasma-treating conditions and the adsorbed DMAEMA amount have remarkable effects on the immobilization degree of DMAEMA. Peroxide determination by 1,1-diphenyl-2-picrvlhydrazyl (DPPH) method verifies the exsistence of radicals induced by plasma, which activize the immobilization reaction. Pure water contact angle on the membrane surface decreased with the increase of DMAEMA immobilization degree, which indicates an enhanced hydrophilicity for the modified membranes. The effects of immobilization degrees on pure water fluxes were also measured. It is shown that pure water fluxes first increased with immobilization degree and then decreased. Finally, permeation of bovine serum albumin (BSA) and lysozyme solution were measured to evaluate the antifouling property of the DMAEMA-modified membranes, from which it is shown that both hydrophilicity and electrostatic repulsion are beneficial for membrane antifouling.

  15. Cascade catalysis in membranes with enzyme immobilization for multienzymatic conversion of CO2 to methanol

    DEFF Research Database (Denmark)

    Luo, Jianquan; Meyer, Anne S.; Mateiu, Ramona Valentina

    2015-01-01

    .e. by directing membrane fouling formation), without any addition of organic solvent. Such coimmobilization and sequential immobilization systems were examined for the production of methanol from CO2 with formate dehydrogenase (FDH), formaldehyde dehydrogenase (FaldDH) and alcohol dehydrogenase (ADH). Enzyme...... for multi-enzymatic cascade systems, but also reveals the reaction bottleneck and provides possible solutions for the bioconversion of CO2 to methanol....

  16. Enveloping bioabsorbable polyglycolide membrane and immobilization in Achilles tendon repair: A comparative experimental study on rabbits.

    Science.gov (United States)

    Pihlajamäki, Harri; Tynninen, Olli; Karjalainen, Pertti; Rokkanen, Pentti

    2008-02-01

    Using qualitative and histoquantitative methods, we investigated the effect of immobilization versus nonimmobilization on the biodegradation process, implant-tissue interaction, and scar formation after enveloping a rejoined rabbit Achilles tendon with a self-reinforced polyglycolide (SR-PGA) membrane. The soleus and gastrocnemius tendons of the right hind legs of 40 rabbits were transected. After suturing the ends, the seam was enveloped with the bioabsorbable membrane. Twenty ankles were immobilized with cast, 20 remained nonimmobilized. All nonoperated left ankles served as intact controls. During the follow-up of 3, 6, 12, and 24 weeks, scar formation, tissue response, and membrane biodegradation were studied histologically and histomorphometrically. The amount of scar tissue, highest at 3 weeks, gradually approached intact controls. SR-PGA degradation in both cast and noncast specimens was near complete by 24 weeks. Signs of an inflammatory process were most prominent at 3 weeks and diminished gradually by 24 weeks. No significant difference between cast and noncast specimens was noted at any time point regarding the amount of scar tissue, degradation process of PGA, or intensity of inflammatory reaction. In the present experimental setting, cast immobilization influenced neither scar formation nor speed of degradation during reunion of transected Achilles tendon ends as compared with nonimmobilization. No differences in the reunion process of the tendon ends were seen between the immobilized and nonimmobilized groups. Moreover, inflammatory cells were similar in both groups and reflected a transient tissue reaction to the membrane. Within the follow-up, the seam area (cross-sectional) approached that of intact controls. (c) 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  17. Quantitative structure-retention relationship studies with immobilized artificial membrane chromatography II: partial least squares regression.

    Science.gov (United States)

    Li, Jie; Sun, Jin; He, Zhonggui

    2007-01-26

    We aimed to establish quantitative structure-retention relationship (QSRR) with immobilized artificial membrane (IAM) chromatography using easily understood and obtained physicochemical molecular descriptors and to elucidate which descriptors are critical to affect the interaction process between solutes and immobilized phospholipid membranes. The retention indices (logk(IAM)) of 55 structurally diverse drugs were determined on an immobilized artificial membrane column (IAM.PC.DD2) directly or obtained by extrapolation method for highly hydrophobic compounds. Ten simple physicochemical property descriptors (clogP, rings, rotatory bond, hydro-bond counting, etc.) of these drugs were collected and used to establish QSRR and predict the retention data by partial least squares regression (PLSR). Five descriptors, clogP, rotatory bond (RotB), rings, molecular weight (MW) and total surface area (TSA), were reserved by using the Variable Importance for Projection (VIP) values as criterion to build the final PLSR model. An external test set was employed to verify the QSRR based on the training set with the five variables, and QSRR by PLSR exhibited a satisfying predictive ability with R(p)=0.902 and RMSE(p)=0.400. Comparison of coefficients of centered and scaled variables by PLSR demonstrated that, for the descriptors studied, clogP and TSA have the most significant positive effect but the rotatable bond has significant negative effect on drug IAM chromatographic retention.

  18. Immobilization of glucoamylase on ceramic membrane surfaces modified with a new method of treatment utilizing SPCP-CVD.

    Science.gov (United States)

    Ida; Matsuyama; Yamamoto

    2000-07-01

    Glucoamylase, as a model enzyme, was immobilized on a ceramic membrane modified by surface corona discharge induced plasma chemical process-chemical vapor deposition (SPCP-CVD). Characterizations of the immobilized enzyme were then discussed. Three kinds of ceramic membranes with different amounts of amino groups on the surface were prepared utilizing the SPCP-CVD method. Each with 1-time, 3-times and 5-times surface modification treatments and used for supports in glucoamylase immobilization. The amount of immobilized glucoamylase increased with the increase in the number of surface modification treatments and saturated to a certain maximum value estimated by a two-dimensional random packing. The operational stability of the immobilized glucoamylase also increased with the increase in the number of the surface treatment. It was almost the same as the conventional method, while the activity of immobilized enzyme was higher. The results indicated the possibility of designing the performance of the immobilized enzyme by controlling the amount of amino groups. The above results showed that the completely new surface modification method using SPCP was effective in modifying ceramic membranes for enzyme immobilization.

  19. Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes for heavy metal removal

    International Nuclear Information System (INIS)

    Genc, Oe.; Soysal, L.; Bayramoglu, G.; Arica, M.Y.; Bektas, S.

    2003-01-01

    The effective removal of toxic heavy metals from environmental samples still remains a major topic of present research. Metal-chelating membranes are very promising materials as adsorbents when compared with conventional beads because they are not compressible, and they eliminate internal diffusion limitations. The purpose of this study was to evaluate the performance of a novel adsorbent, Procion Green H-4G immobilized poly(hydroxyethylmethacrylate (HEMA)/chitosan) composite membranes, for the removal of three toxic heavy metal ions, namely, Cd(II), Pb(II) and Hg(II) from aquatic systems. The Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes were characterized by elemental analysis, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The immobilized amount of the Procion Green H-4G was calculated as 0.018±0.003 μmol/cm 2 from the nitrogen and sulphur stoichiometry. The adsorption capacity of Procion Green H-4G immobilized poly(hydroxyethylmethacrylate/chitosan) composite membranes for selected heavy metal ions from aqueous media containing different amounts of these ions (30-400 mg/l) and at different pH values (2.0-6.0) was investigated. The amount of Cd(II), Pb(II) and Hg(II) adsorbed onto the membranes measured at equilibrium, increased with time during the first 45 min and then remained unchanged toward the equilibrium adsorption. The maximum amounts of heavy metal ions adsorbed were 43.60±1.74, 68.81±2.75 and 48.22±1.92 mg/g for Cd(II), Pb(II) and Hg(II), respectively. The heavy metal ion adsorption on the pHEMA/chitosan membranes (carrying no dye) were relatively low, 6.31±0.13 mg/g for Cd(II), 18.73±0.37 mg/g for Pb(II) and 18.82±0.38 mg/g for Hg(II). Competitive adsorption of the metal ions was also studied. When the metal ions competed with each other, the adsorbed amounts were 12.74±0.38 mg Cd(II)/g, 28.80±0.86 mg Pb(II)/g and 18.41±0.54 mg Hg(II)/g. Procion Green H-4G

  20. Hydrolysis of whey lactose by immobilized β-galactosidase in a bioreactor with a spirally wound membrane.

    Science.gov (United States)

    Vasileva, Nastya; Ivanov, Yavor; Damyanova, Stanka; Kostova, Iliana; Godjevargova, Tzonka

    2016-01-01

    The β-galactosidase was covalently immobilized onto a modified polypropylene membrane, using glutaraldehyde. The optimal conditions for hydrolysis of lactose (4.7%) by immobilized β-galactosidase in a batch process were determined 13.6 U enzyme activity, 40°C, pH 6.8 and 10h. The obtained degree of hydrolysis was compared with results received by a free enzyme. It was found, that the lactose hydrolysis by an immobilized enzyme was 1.6 times more effective than the lactose hydrolysis by a free enzyme. It was determined that the stability of the immobilized enzyme was 2 times higher in comparison with the stability of free enzyme. The obtained immobilized system β-galactosidase/polypropylene membrane was applied to produce glucose-galactose syrup from waste whey. The whey characteristics and the different preliminary treatments of the whey were investigated. Then the whey lactose hydrolysis in a bioreactor by an immobilized enzyme on a spirally wound membrane was performed. The optimal membrane surface and the optimal flow rate of the whey through the membrane module were determined, respectively 100 cm(2) and 1.0 mL min(-1). After 10h, the degree of lactose hydrolysis was increased to 91%. The operation stability was studied. After 20th cycle the yield of bioreactor was 69.7%. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Function of membrane protein in silica nanopores: incorporation of photosynthetic light-harvesting protein LH2 into FSM.

    Science.gov (United States)

    Oda, Ippei; Hirata, Kotaro; Watanabe, Syoko; Shibata, Yutaka; Kajino, Tsutomu; Fukushima, Yoshiaki; Iwai, Satoshi; Itoh, Shigeru

    2006-01-26

    A high amount of functional membrane protein complex was introduced into a folded-sheet silica mesoporous material (FSM) that has nanometer-size pores of honeycomb-like hexagonal cylindrical structure inside. The photosynthetic light-harvesting complex LH2, which is a typical membrane protein, has a cylindrical structure of 7.3 nm diameter and contains 27 bacteriochlorophyll a and nine carotenoid molecules. The complex captures light energy in the anoxygenic thermophilic purple photosynthetic bacterium Thermochromatium tepidum. The amount of LH2 adsorbed to FSM was determined optically and by the adsorption isotherms of N2. The FSM compounds with internal pore diameters of 7.9 and 2.7 nm adsorbed LH2 at 1.11 and 0.24 mg/mg FSM, respectively, suggesting the high specific affinity of LH2 to the interior of the hydrophobic nanopores with a diameter of 7.9 nm. The LH2 adsorbed to FSM showed almost intact absorption bands of bacteriochlorophylls, and was fully active in the capture and transfer of excitation energy. The LH2 complex inside the FSM showed increased heat stability of the exciton-type absorption band of bacteriochlorophylls (B850), suggesting higher circular symmetry. The environment inside the hydrophobic silica nanopores can be a new matrix for the membrane proteins to reveal their functions. The silica-membrane protein adduct will be useful for the construction of new probes and reaction systems.

  2. Immobilization of Na,K-ATPase isolated from rat brain synaptic plasma membranes

    Directory of Open Access Journals (Sweden)

    ANICA HROVAT

    2002-12-01

    Full Text Available Rat brain Na,K-ATPase partially purified by SDS from synaptic plasma membranes (SPM was immobilized by adsorption on nitrocellulose (NC, polyvinylidene fluoride (PVDF and glass fiber (GF membranes. Partial SDS solubilization increased the enzyme activity by 40 %. With regard to the preservation of the enzyme activity, nitrocellulose was shown to be the optimal support for the immobilization. The enzyme showed the highest percentage activity (14 % after 30 min of SPM adsorption, at 20°C under the vaccum, with 25 mg of proteins per NC disc filter. In addition, adsorption on NC stabilizes the Na,K-ATPase, since the activity was substantial 72 h after adsorption at 20°C. After adsorption, the sensitivity of the enzyme to HgCl2and CdCll2 inhibition was higher. The results show that immobilized Na,K-ATPase SPM can be used as a practical model for the detection of metal ions in different samples.

  3. Virus disinfection in water by biogenic silver immobilized in polyvinylidene fluoride membranes

    Energy Technology Data Exchange (ETDEWEB)

    Gusseme, B.D.; Fitts, J.; Hennebel, T.; Christiaens, E.; Saveyn, H.; Verbeken, K.; Boon, N.; Verstraete, W.

    2011-03-01

    The development of innovative water disinfection strategies is of utmost importance to prevent outbreaks of waterborne diseases related to poor treatment of (drinking) water. Recently, the association of silver nanoparticles with the bacterial cell surface of Lactobacillus fermentum (referred to as biogenic silver or bio-Ag{sup 0}) has been reported to exhibit antiviral properties. The microscale bacterial carrier matrix serves as a scaffold for Ag{sup 0} particles, preventing aggregation during encapsulation. In this study, bio-Ag{sup 0} was immobilized in different microporous PVDF membranes using two different pre-treatments of bio-Ag{sup 0} and the immersion-precipitation method. Inactivation of UZ1 bacteriophages using these membranes was successfully demonstrated and was most probably related to the slow release of Ag{sup +} from the membranes. At least a 3.4 log decrease of viruses was achieved by application of a membrane containing 2500 mg bio-Ag{sub powder}{sup 0} m{sup -2} in a submerged plate membrane reactor operated at a flux of 3.1 L m{sup -2} h{sup -1}. Upon startup, the silver concentration in the effluent initially increased to 271 {micro}g L{sup -1} but after filtration of 31 L m{sup -2}, the concentration approached the drinking water limit (= 100 {micro}g L{sup -1}). A virus decline of more than 3 log was achieved at a membrane flux of 75 L m{sup -2} h{sup -1}, showing the potential of this membrane technology for water disinfection on small scale. In biogenic silver, silver nanoparticles are attached to a bacterial carrier matrix. Bio-Ag{sup 0} was successfully immobilized in PVDF membranes using immersion-precipitation. The antiviral activity of this material was demonstrated in a plate membrane reactor. The antimicrobial mechanism was most probably related to the slow release of Ag{sup +} ions. The membranes can be applied for treatment of limited volumes of contaminated water.

  4. Surface modification of polysulfone membranes applied for a membrane reactor with immobilized alcohol dehydrogenase

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Silau, Harald; Pinelo, Manuel

    2018-01-01

    activated by lithiation followed by functionalization with acid chlorides at 0 °C, permitting modification of commercial PSf membranes without compromising the mechanical integrity of the membrane. Post-functionalization polymer grafting was illustrated through both, a “grafting from” approach by surface...... initiated atom transfer radical polymerization (SI-ATRP) and by a “grafting to” approach exploiting Cu(I) catalyzed 1,3-cycloadditions of alkynes with azides (CuAAC) introducing hydrophilic polymers onto the membrane surface. Poly(1-vinyl imidazole) (pVim) grafted membranes were exploited as support...

  5. Significance of membrane bioreactor design on the biocatalytic performance of glucose oxidase and catalase: Free vs. immobilized enzyme systems

    DEFF Research Database (Denmark)

    Morthensen, Sofie Thage; Meyer, Anne S.; Jørgensen, Henning

    2017-01-01

    Membrane separation of xylose and glucose can be accomplished via oxidation of glucose to gluconic acid by enzymatic glucose oxidase catalysis. Oxygen for this reaction can be supplied via decomposition of hydrogen peroxide by enzymatic catalase catalysis. In order to maximize the biocatalytic...... productivity of glucose oxidase and catalase (gluconic acid yield per total amount of enzyme) the following system set-ups were compared: immobilization of glucose oxidase alone; co-immobilization of glucose oxidase and catalase; glucose oxidase and catalase free in the membrane bioreactor. Fouling......-induced enzyme immobilization in the porous support of an ultrafiltration membrane was used as strategy for entrapment of glucose oxidase and catalase. The biocatalytic productivity of the membrane reactor was found to be highly related to the oxygen availability, which in turn depended on the reactor...

  6. 2H NMR evidence for antibiotic-induced cholesterol immobilization in biological model membranes

    International Nuclear Information System (INIS)

    Dufourc, E.J.; Smith, I.C.

    1985-01-01

    The interaction of the polyene antibiotic filipin with membrane sterols has been studied by deuterium nuclear magnetic resonance of the molecular probes [2,2,3,4,4,6- 2 H6]cholesterol and 1-myristoyl-2-[4',4',14',14',14'- 2 H5]myristoyl-sn-glycero-3-phospho- choline. At physiological temperatures, there is evidence of filipin-induced cholesterol immobilization in the membrane. The 2 H NMR spectra of cholesterol show two domains in which ordering and dynamics are very different. In one of these, cholesterol is static on the 2 H NMR time scale, whereas in the other it undergoes rapid axially symmetric motions similar to those it exhibits in the drug-free membrane; this indicates that the jumping frequency of cholesterol between the labile and immobilized domains is less than 10(5) s -1 . The distribution of cholesterol between these two sites is temperature dependent. In contrast to cholesterol, the phospholipids sense only one type of environment, at both the top and center of the bilayer, indicating that cholesterol acts as a screen, preventing the lipids from direct interaction with the antibiotic. At low temperature, the ordering of the lipid in the presence of cholesterol does not change upon filipin addition, whereas at elevated temperatures the local ordering of both the lipid and the labile cholesterol is significantly lower than that in the absence of the drug

  7. 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

  8. Virus Disinfection in Water by Biogenic Silver Immobilized in Polyvinylidene Fluoride Membranes

    Energy Technology Data Exchange (ETDEWEB)

    B De Gusseme; T Hennebel; E Christiaens; H Saveyn; K Verbeken; J Fitts; N Boon; W Vertraete

    2011-12-31

    The development of innovative water disinfection strategies is of utmost importance to prevent outbreaks of waterborne diseases related to poor treatment of (drinking) water. Recently, the association of silver nanoparticles with the bacterial cell surface of Lactobacillus fermentum (referred to as biogenic silver or bio-Ag{sup 0}) has been reported to exhibit antiviral properties. The microscale bacterial carrier matrix serves as a scaffold for Ag{sup 0} particles, preventing aggregation during encapsulation. In this study, bio-Ag{sup 0} was immobilized in different microporous PVDF membranes using two different pre-treatments of bio-Ag{sup 0} and the immersion-precipitation method. Inactivation of UZ1 bacteriophages using these membranes was successfully demonstrated and was most probably related to the slow release of Ag{sup +} from the membranes. At least a 3.4 log decrease of viruses was achieved by application of a membrane containing 2500 mg bio-Ag{sup 0}{sub powder} m{sup -2} in a submerged plate membrane reactor operated at a flux of 3.1 L m{sup -2} h{sup -1}. Upon startup, the silver concentration in the effluent initially increased to 271 {mu}g L{sub -1} but after filtration of 31 L m{sup -2}, the concentration approached the drinking water limit (= 100 {mu}g L{sup -1}). A virus decline of more than 3 log was achieved at a membrane flux of 75 L m{sup -2} h{sup -1}, showing the potential of this membrane technology for water disinfection on small scale.

  9. Trypsin immobilization in ordered porous polymer membranes for effective protein digestion

    International Nuclear Information System (INIS)

    Qiao, Juan; Kim, Jin Yong; Wang, Yuan Yuan; Qi, Li; Wang, Fu Yi; Moon, Myeong Hee

    2016-01-01

    Fast and effective protein digestion is a vital process for mass spectrometry (MS) based protein analysis. This study introduces a porous polymer membrane enzyme reactor (PPMER) coupled to nanoflow liquid chromatography-tandem MS (nLC-ESI-MS/MS) for on-line digestion and analysis of proteins. Poly (styrene-co-maleic anhydride) (PS-co-MAn) was fabricated by the breath figure method to make a porous polymer membrane in which the MAn group was covalently bound to enzyme. Based on this strategy, microscale PPMER (μPPMER) was constructed for on-line connection with the nLC-ESI-MS/MS system. Its capability for enzymatic digestion with bovine serum albumin (BSA) was evaluated with varied digestion periods. The on-line proteolysis of BSA and subsequent analysis with μPPMER-nLC-ESI-MS/MS revealed that peptide sequence coverage increased from 10.3% (digestion time 10 min) to 89.1% (digestion time 30 min). μPPMER can efficiently digest proteins due to the microscopic confinement effect, showing its potential application in fast protein identification and protease immobilization. Applications of on-line digestion using μPPMER with human plasma and urinary proteome samples showed that the developed on-line method yielded equivalent or better performance in protein coverage and identified more membrane proteins than the in-solution method. This may be due to easy accommodation of hydrophobic membrane proteins within membrane pores. - Highlights: • A porous polymer membrane enzyme reactor was developed. • Breath figure method was used for the fabrication of porous polymer membrane. • The enzyme reactor was coupled to nLC-ESI-MS/MS for proteins on-line digestion.

  10. Trypsin immobilization in ordered porous polymer membranes for effective protein digestion

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Juan [Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190 (China); Kim, Jin Yong [Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seoul 120-749 (Korea, Republic of); Wang, Yuan Yuan [Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190 (China); Qi, Li, E-mail: qili@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190 (China); Wang, Fu Yi [Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Zhongguancun Beiyijie, Beijing 100190 (China); Moon, Myeong Hee, E-mail: mhmoon@yonsei.ac.kr [Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seoul 120-749 (Korea, Republic of)

    2016-02-04

    Fast and effective protein digestion is a vital process for mass spectrometry (MS) based protein analysis. This study introduces a porous polymer membrane enzyme reactor (PPMER) coupled to nanoflow liquid chromatography-tandem MS (nLC-ESI-MS/MS) for on-line digestion and analysis of proteins. Poly (styrene-co-maleic anhydride) (PS-co-MAn) was fabricated by the breath figure method to make a porous polymer membrane in which the MAn group was covalently bound to enzyme. Based on this strategy, microscale PPMER (μPPMER) was constructed for on-line connection with the nLC-ESI-MS/MS system. Its capability for enzymatic digestion with bovine serum albumin (BSA) was evaluated with varied digestion periods. The on-line proteolysis of BSA and subsequent analysis with μPPMER-nLC-ESI-MS/MS revealed that peptide sequence coverage increased from 10.3% (digestion time 10 min) to 89.1% (digestion time 30 min). μPPMER can efficiently digest proteins due to the microscopic confinement effect, showing its potential application in fast protein identification and protease immobilization. Applications of on-line digestion using μPPMER with human plasma and urinary proteome samples showed that the developed on-line method yielded equivalent or better performance in protein coverage and identified more membrane proteins than the in-solution method. This may be due to easy accommodation of hydrophobic membrane proteins within membrane pores. - Highlights: • A porous polymer membrane enzyme reactor was developed. • Breath figure method was used for the fabrication of porous polymer membrane. • The enzyme reactor was coupled to nLC-ESI-MS/MS for proteins on-line digestion.

  11. Equilibration kinetics in isolated and membrane-bound photosynthetic reaction centers upon illumination: a method to determine the photoexcitation rate.

    Science.gov (United States)

    Manzo, Anthony J; Goushcha, Alexander O; Barabash, Yuri M; Kharkyanen, Valery N; Scott, Gary W

    2009-07-01

    Kinetics of electron transfer, following variation of actinic light intensity, for photosynthetic reaction centers (RCs) of purple bacteria (isolated and membrane-bound) were analyzed by measuring absorbance changes in the primary photoelectron donor absorption band at 865 nm. The bleaching of the primary photoelectron donor absorption band in RCs, following a sudden increase of illumination from the dark to an actinic light intensity of I(exp), obeys a simple exponential law with the rate constant alphaI(exp) + k(rec), in which alpha is a parameter relating the light intensity, measured in mW/cm(2), to a corresponding theoretical rate in units of reciprocal seconds, and k(rec) is the effective rate constant of the charge recombination in the photosynthetic RCs. In this work, a method for determining the alpha parameter value is developed and experimentally verified for isolated and membrane-bound RCs, allowing for rigorous modeling of RC macromolecule dynamics under varied photoexcitation conditions. Such modeling is necessary for RCs due to alterations of the forward photoexcitation rates and relaxation rates caused by illumination history and intramolecular structural dynamics effects. It is demonstrated that the classical Bouguer-Lambert-Beer formalism can be applied for the samples with relatively low scattering, which is not necessarily the case with strongly scattering media or high light intensity excitation.

  12. Advances in immobilized artificial membrane (IAM) chromatography for novel drug discovery.

    Science.gov (United States)

    Tsopelas, Fotios; Vallianatou, Theodosia; Tsantili-Kakoulidou, Anna

    2016-01-01

    The development of immobilized artificial membrane (IAM) chromatography has unfolded new perspectives for the use of chromatographic techniques in drug discovery, combining simulation of the environment of cell membranes with rapid measurements. The present review describes the characteristics of phosphatidylcholine-based stationary phases and analyses the molecular factors governing IAM retention in comparison to n-octanol-water and liposomes partitioning systems as well as to reversed phase chromatography. Other biomimetic stationary phases are also briefly discussed. The potential of IAM chromatography to model permeability through the main physiological barriers and drug membrane interactions is outlined. Further applications to calculate complex pharmacokinetic properties, related to tissue binding, and to screen drug candidates for phospholipidosis, as well as to estimate cell accumulation/retention are surveyed. The ambivalent nature of IAM chromatography, as a border case between passive diffusion and binding, defines its multiple potential applications. However, despite its successful performance in many permeability and drug-membrane interactions studies, IAM chromatography is still used as a supportive and not a stand-alone technique. Further studies looking at IAM chromatography in different biological processes are still required if this technique is to have a more focused and consistent application in drug discovery.

  13. Liquid anion exchangers (LAE) as novel receptors for plutonium pertraction across polymer immobilized liquid membranes

    International Nuclear Information System (INIS)

    Sonawane, J.V.; Anil Kumar; Sawant, S.R.; Singh, R.K.; Bajpai, D.D.; Shukla, J.P.

    1999-03-01

    The diffusion-limited and amine-facilitated Pu 4+ cation permeation in nitric acid media across a polymer immobilized liquid membrane (PILM) has been investigated to quantify the membrane carrier type effects on its transport. Primene JM-T (JMT) as primary, Amberlite LA-2 (Amb LA-2) as secondary, trilaurylamine (TLA] and triiso-octyl amine (TIOA) as tertiary and Adogen-464 (Ado-464) and Aliquat-336 (Ali-336) as quaternary amines as typical examples of nitrogen containing basic extractants are tested as the carriers. After suitable dilutions, the receptors are immobilized on a microporous polymeric support which are held within the pores by capillary forces. Both the composition of the organic membrane solvents and type of amine carriers exert a marked effect on plutonium permeation. Recovery of Pu steadily increases from primary to quaternary amines; its permeability across PILM roughly follows the order quaternary > tertiary > secondary > primary, similar to that generally observed in liquid-liquid distribution experiments. More than 95% pertraction of Pu(IV) is easily accomplished using tertiary or quaternary amine as ionophores across PILM in single run employing a feed solution containing about 5 mg dm -3 Pu in 4 M nitric acid solution while the receiving phase is 0.1M NH 2 OH.HCl prepared in 0.3M HNO 3 . On the other hand, plutonium permeation at 4M HNO 3 under similar experimental conditions using other types of amines as carriers namely primary amine, Pri JM-T afforded only 19% and 49% by Amb LA-2 in 6-7h runs. Results of the detailed study to evaluate the effect of other contaminants on Pu transport are also discussed. (author)

  14. Lipase immobilized on the hydrophobic polytetrafluoroethene membrane with nonwoven fabric and its application in intensifying synthesis of butyl oleate.

    Science.gov (United States)

    Wang, Shu-Guang; Zhang, Wei-Dong; Li, Zheng; Ren, Zhong-Qi; Liu, Hong-Xia

    2010-11-01

    The synthesis of butyl oleate was studied in this paper with immobilized lipase. Five types of membrane were used as support to immobilize Rhizopus arrhizus lipase by following a procedure combining filtration and protein cross-linking. Results showed that hydrophobic polytetrafluoroethene membrane with nonwoven fabric (HO-PTFE-NF) was the favorite choice in terms of higher protein loading, activity, and specific activity of immobilized lipase. The factors including solvent polarity, lipase dosage, concentration, and molar ratio of substrate and temperature were found to have significant influence on conversion. Results showed that hexane (logP = 3.53) was a favorable solvent for the biosynthesis of butyl oleate in our studies. The optimal conditions were experimentally determined of 50 U immobilized lipase, molar ratio of oleic acid to butanol of 1.0, substrate concentration of 0.12 mol/L, temperature of 37 °C, and reaction time of 2 h. The conversion was beyond 91% and decreased slightly after 18 cycles. Lipase immobilization can improve the conversion and the repeated use of immobilized lipase relative to free lipase.

  15. A Glucose Sensor Based on Glucose Oxidase Immobilized by Electrospinning Nanofibrous Polymer Membranes Modified with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    You Wang

    2013-05-01

    Full Text Available A glucose biosensor based on glucose oxidase immobilized by electrospinning nanofibrous membranes has been developed. Nanofibrous membranes were electrospun from the solution of poly(acrylonitrile-co-acrylic acid containing carbon nanotubes suspension and directly deposited on Pt electrodes for immobilizing glucose oxidase. The morphologies and structure of the nanofibrous membranes with or without carbon nanotubes were characterized by scanning electron microscopy. The fabrication parameters of nanofibers were optimized such as thickness of the nanofibrous membranes and mass ration of carbon nanotubes. The biosensor showed the relationship with a concentration range of 0.1–10 mM and response time was 60 s. The sensitivity of carbon nanotubes modified biosensors was two times larger than which of no carbon nanotubes modified ones. The pH effect, interference and lifetime of biosensors were discussed.

  16. Development of double chain phosphatidylcholine functionalized polymeric monoliths for immobilized artificial membrane chromatography.

    Science.gov (United States)

    Wang, Qiqin; Peng, Kun; Chen, Weijia; Cao, Zhen; Zhu, Peijie; Zhao, Yumei; Wang, Yuqiang; Zhou, Haibo; Jiang, Zhengjin

    2017-01-06

    This study described a simple synthetic methodology for preparing biomembrane mimicking monolithic column. The suggested approach not only simplifies the preparation procedure but also improves the stability of double chain phosphatidylcholine (PC) functionalized monolithic column. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and nano-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained on this double chain PC functionalized monolithic column. It is worth noting that the resulting polymeric monolith exhibits great potential as a useful alternative of commercial immobilized artificial membrane (IAM) columns for in vitro predication of drug-membrane interactions. Furthermore, the comparative study of both double chain and single chain PC functionalized monoliths indicates that the presence or absence of glycerol backbone and the number of acyl chains are not decisive for the predictive ability of IAM monoliths on drug-membrane interactions. This novel PC functionalized monolithic column also exhibited good selectivity for a protein mixture and a set of pharmaceutical compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Trans-membrane electron transfer in red blood cells immobilized in a chitosan film on a glassy carbon electrode

    International Nuclear Information System (INIS)

    Yu, Chunmei; Wang, Li; Zhu, Zhenkun; Bao, Ning; Gu, Haiying

    2014-01-01

    We have studied the trans-membrane electron transfer in human red blood cells (RBCs) immobilized in a chitosan film on a glassy carbon electrode (GCE). Electron transfer results from the presence of hemoglobin (Hb) in the RBCs. The electron transfer rate (k s ) of Hb in RBCs is 0.42 s −1 , and <1.13 s −1 for Hb directly immobilized in the chitosan film. Only Hb molecules in RBCs that are closest to the plasma membrane and the surface of the electrode can undergo electron transfer to the electrode. The immobilized RBCs displayed sensitive electrocatalytic response to oxygen and hydrogen peroxide. It is believed that this cellular biosensor is of potential significance in studies on the physiological status of RBCs based on observing their electron transfer on the modified electrode. (author)

  18. Synthesis of an oligonucleotide-derivatized amphipol and its use to trap and immobilize membrane proteins

    DEFF Research Database (Denmark)

    Bon, Christel Le; Della Pia, Eduardo Antonio; Giusti, Fabrice

    2014-01-01

    'OligAPol' have been investigated. Grafting was performed by reacting an ODN carrying an amine-terminated arm with the carboxylates of A8-35. The use of OligAPol for trapping MPs and immobilizing them onto solid supports was tested using bacteriorhodopsin (BR) and the transmembrane domain of Escherichia...... coli outer membrane protein A (tOmpA) as model proteins. BR and OligAPol form water-soluble complexes in which BR remains in its native conformation. Hybridization of the ODN arm with a complementary ODN was not hindered by the assembly of OligAPol into particles, nor by its association with BR. BR....../OligAPol and tOmpA/OligAPol complexes could be immobilized onto either magnetic beads or gold nanoparticles grafted with the complementary ODN, as shown by spectroscopic measurements, fluorescence microscopy and the binding of anti-BR and anti-tOmpA antibodies. OligAPols provide a novel, highly versatile...

  19. Free fatty acids and esters can be immobilized by receptor rich membranes from torpedo marmorata but not phospholipid acyl chains

    NARCIS (Netherlands)

    Rousselet, A.; Devaux, P.F.; Wirtz, K.W.A.

    1979-01-01

    A long chain spin labeled fatty acid and the corresponding ester have been introduced into receptor rich membranes from Torpedo Marmorata. Superimposed to a mobile component, typical of the lipid phase, a strongly immobilized component is seen on the ESR spectra, both at low temperature (−4°C) and

  20. Quantitative structure-retention relationships of flavonoids unraveled by immobilized artificial membrane chromatography.

    Science.gov (United States)

    Santoro, Adriana Leandra; Carrilho, Emanuel; Lanças, Fernando Mauro; Montanari, Carlos Alberto

    2016-06-10

    The pharmacokinetic properties of flavonoids with differing degrees of lipophilicity were investigated using immobilized artificial membranes (IAMs) as the stationary phase in high performance liquid chromatography (HPLC). For each flavonoid compound, we investigated whether the type of column used affected the correlation between the retention factors and the calculated octanol/water partition (log Poct). Three-dimensional (3D) molecular descriptors were calculated from the molecular structure of each compound using i) VolSurf software, ii) the GRID method (computational procedure for determining energetically favorable binding sites in molecules of known structure using a probe for calculating the 3D molecular interaction fields, between the probe and the molecule), and iii) the relationship between partition and molecular structure, analyzed in terms of physicochemical descriptors. The VolSurf built-in Caco-2 model was used to estimate compound permeability. The extent to which the datasets obtained from different columns differ both from each other and from both the calculated log Poct and the predicted permeability in Caco-2 cells was examined by principal component analysis (PCA). The immobilized membrane partition coefficients (kIAM) were analyzed using molecular descriptors in partial least square regression (PLS) and a quantitative structure-retention relationship was generated for the chromatographic retention in the cholesterol column. The cholesterol column provided the best correlation with the permeability predicted by the Caco-2 cell model and a good fit model with great prediction power was obtained for its retention data (R(2)=0.96 and Q(2)=0.85 with four latent variables). Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Optimal fold symmetry of LH2 rings on a photosynthetic membrane.

    Science.gov (United States)

    Cleary, Liam; Chen, Hang; Chuang, Chern; Silbey, Robert J; Cao, Jianshu

    2013-05-21

    An intriguing observation of photosynthetic light-harvesting systems is the N-fold symmetry of light-harvesting complex 2 (LH2) of purple bacteria. We calculate the optimal rotational configuration of N-fold rings on a hexagonal lattice and establish two related mechanisms for the promotion of maximum excitation energy transfer (EET). (i) For certain fold numbers, there exist optimal basis cells with rotational symmetry, extendable to the entire lattice for the global optimization of the EET network. (ii) The type of basis cell can reduce or remove the frustration of EET rates across the photosynthetic network. We find that the existence of a basis cell and its type are directly related to the number of matching points S between the fold symmetry and the hexagonal lattice. The two complementary mechanisms provide selection criteria for the fold number and identify groups of consecutive numbers. Remarkably, one such group consists of the naturally occurring 8-, 9-, and 10-fold rings. By considering the inter-ring distance and EET rate, we demonstrate that this group can achieve minimal rotational sensitivity in addition to an optimal packing density, achieving robust and efficient EET. This corroborates our findings i and ii and, through their direct relation to S, suggests the design principle of matching the internal symmetry with the lattice order.

  2. Solution phase and membrane immobilized iron-based free radical reactions: Fundamentals and applications for water treatment

    Science.gov (United States)

    Lewis, Scott Romak

    Membrane-based separation processes have been used extensively for drinking water purification, wastewater treatment, and numerous other applications. Reactive membranes synthesized through functionalization of the membrane pores offer enhanced reactivity due to increased surface area at the polymer-solution interface and low diffusion limitations. Oxidative techniques utilizing free radicals have proven effective for both the destruction of toxic organics and non-environmental applications. Most previous work focuses on reactions in the homogeneous phase; however, the immobilization of reactants in membrane pores offers several advantages. The use of polyanions immobilized in a membrane or chelates in solution prevents ferric hydroxide precipitation at near-neutral pH, a common limitation of iron(Fe(II/III))-catalyzed hydrogen peroxide (H 2O2) decomposition. The objectives of this research are to develop a membrane-based platform for the generation of free radicals, degrade toxic organic compounds using this and similar solution-based reactions, degrade toxic organic compounds in droplet form, quantify hydroxyl radical production in these reactions, and develop kinetic models for both processes. In this study, a functionalized membrane containing poly(acrylic acid) (PAA) was used to immobilize iron ions and conduct free radical reactions by permeating H2O2 through the membrane. The membrane's responsive behavior to pH and divalent cations was investigated and modeled. The conversion of Fe(II) to Fe(III) in the membrane and its effect on the decomposition of hydrogen peroxide were monitored and used to develop kinetic models for predicting H2O2 decomposition in these systems. The rate of hydroxyl radical production, and hence contaminant degradation can be varied by changing the residence time, H2O2 concentration, and/or iron loading. Using these membrane-immobilized systems, successful removal of toxic organic compounds, such as pentachlorophenol (PCP), from water

  3. Immobilization of ionophore and surface characterization studies of the titanium(III) ion in a PVC-membrane sensor.

    Science.gov (United States)

    Rezayi, Majid; Heng, Lee Yook; Kassim, Anuar; Ahmadzadeh, Saeid; Abdollahi, Yadollah; Jahangirian, Hossein

    2012-01-01

    Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride) (PVC) matrices, and these were examined to determine Ti(III) selectivity. To predict the selectivity of Ti(III), a PVC membrane was used to investigate the binding of Ti(III) to c-methylcalix[4]resorcinarene (CMCR). The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III) at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl) borate (NaTFPB) as a lipophilic ionic additive, and dioctylphthalate (DOP) as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs). The strengths of the ion-ionophore (CMCR-Ti(OH)(OH(2))(5) (2+)) interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and and X-ray diffraction (XRD).

  4. PAN-Immobilized PVC-NPOE Membrane for Environmentally Friendly Sensing of Cd(II Ions

    Directory of Open Access Journals (Sweden)

    Moersilah Moersilah

    2017-04-01

    Full Text Available A simple, cheap and environmentally friendly analytical method of Cd(II in the aqueous system has been developed by immobilization of 1-(2-pyridilazo-2-naphtol (PAN in poly vinyl chloride (PVC matrix and nitrophenyl octyl ether (NPOE as a plasticizer. Upon contact with Cd(II in solution, the color of sensor membrane changes from dark yellow to dark red, which is due to the formation of Cd(II–PAN complex. The best sensing results were obtained at pH 8.0 and λmax 558 nm. The dimension of the proposed sensor membrane was 0.8 cm x 2 cm with a thickness of 0.05 mm, the volume of sample was 2 mL with the Cd(II concentration range of  0 – 1.2 ppm. The limit of detection of the method was found to be 0.432 + 0.104 ppm, which was reversible. The proposed methods have been applied in the determination of Cd(II in water samples after addition of internal standard.

  5. High-throughput hydrolysis of starch during permeation across α-amylase-immobilized porous hollow-fiber membranes

    Science.gov (United States)

    Miura, Suguru; Kubota, Noboru; Kawakita, Hidetaka; Saito, Kyoichi; Sugita, Kazuyuki; Watanabe, Kohei; Sugo, Takanobu

    2002-02-01

    Two kinds of supporting porous membranes, ethanolamine (EA) and phenol (Ph) fibers, for immobilization of α-amylase were prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer, glycidyl methacrylate, onto a porous hollow-fiber membrane, and subsequent ring-opening with EA and Ph, respectively. An α-amylase solution was forced to permeate radially outward through the pores of the EA and Ph fibers. α-Amylase was captured at a density of 0.15 and 6.6 g/L of the membrane by the graft chain containing 2-hydroxyethylamino and phenyl groups, respectively. A permeation pressure of 0.10 MPa provided a space velocity of 780 and 1500 h -1 for the α-amylase-immobilized EA and Ph fibers, respectively. Quantitative hydrolysis of starch during permeation of a 20 g/L starch solution in the buffer across the α-amylase-immobilized Ph fiber was attained up to a space velocity of about 2000 h -1; this was achieved because of negligible diffusional mass-transfer resistance of the starch to the α-amylase due to convective flow, whereas an enzyme reaction-controlled system was observed for the α-amylase-immobilized EA fiber.

  6. High-throughput hydrolysis of starch during permeation across α-amylase-immobilized porous hollow-fiber membranes

    International Nuclear Information System (INIS)

    Miura, Suguru; Kubota, Noboru; Kawakita, Hidetaka; Saito, Kyoichi; Sugita, Kazuyuki; Watanabe, Kohei; Sugo, Takanobu

    2002-01-01

    Two kinds of supporting porous membranes, ethanolamine (EA) and phenol (Ph) fibers, for immobilization of α-amylase were prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer, glycidyl methacrylate, onto a porous hollow-fiber membrane, and subsequent ring-opening with EA and Ph, respectively. An α-amylase solution was forced to permeate radially outward through the pores of the EA and Ph fibers. α-Amylase was captured at a density of 0.15 and 6.6 g/L of the membrane by the graft chain containing 2-hydroxyethylamino and phenyl groups, respectively. A permeation pressure of 0.10 MPa provided a space velocity of 780 and 1500 h -1 for the α-amylase-immobilized EA and Ph fibers, respectively. Quantitative hydrolysis of starch during permeation of a 20 g/L starch solution in the buffer across the α-amylase-immobilized Ph fiber was attained up to a space velocity of about 2000 h -1 ; this was achieved because of negligible diffusional mass-transfer resistance of the starch to the α-amylase due to convective flow/ whereas an enzyme reaction-controlled system was observed for the α-amylase-immobilized EA fiber.

  7. High-throughput hydrolysis of starch during permeation across {alpha}-amylase-immobilized porous hollow-fiber membranes

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Suguru; Kubota, Noboru; Kawakita, Hidetaka; Saito, Kyoichi E-mail: marukyo@xtal.tf.chiba-u.ac.jp; Sugita, Kazuyuki; Watanabe, Kohei; Sugo, Takanobu

    2002-02-01

    Two kinds of supporting porous membranes, ethanolamine (EA) and phenol (Ph) fibers, for immobilization of {alpha}-amylase were prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer, glycidyl methacrylate, onto a porous hollow-fiber membrane, and subsequent ring-opening with EA and Ph, respectively. An {alpha}-amylase solution was forced to permeate radially outward through the pores of the EA and Ph fibers. {alpha}-Amylase was captured at a density of 0.15 and 6.6 g/L of the membrane by the graft chain containing 2-hydroxyethylamino and phenyl groups, respectively. A permeation pressure of 0.10 MPa provided a space velocity of 780 and 1500 h{sup -1} for the {alpha}-amylase-immobilized EA and Ph fibers, respectively. Quantitative hydrolysis of starch during permeation of a 20 g/L starch solution in the buffer across the {alpha}-amylase-immobilized Ph fiber was attained up to a space velocity of about 2000 h{sup -1}; this was achieved because of negligible diffusional mass-transfer resistance of the starch to the {alpha}-amylase due to convective flow/ whereas an enzyme reaction-controlled system was observed for the {alpha}-amylase-immobilized EA fiber.

  8. Encapsulation and immobilization of papain in electrospun nanofibrous membranes of PVA cross-linked with glutaraldehyde vapor

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Cortez, Iván E. [Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna # 140, San José de los Cerritos, Saltillo, Coahuila 25100, México (Mexico); Universidad Autónoma de Nuevo León (UANL), Fac. de Ingeniería Mecánica y Eléctrica (FIME), Av. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450, México (Mexico); Universidad Autónoma de Nuevo León (UANL), Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología (CIIDIT), Apodaca, Nuevo León, México (Mexico); Romero-García, Jorge, E-mail: jromero@ciqa.mx [Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna # 140, San José de los Cerritos, Saltillo, Coahuila 25100, México (Mexico); and others

    2015-07-01

    In this paper, papain enzyme (E.C. 3.4.22.2, 1.6 U/mg) was successfully immobilized in poly(vinyl alcohol) (PVA) nanofibers prepared by electrospinning. The morphology of the electrospun nanofibers was characterized by scanning electron microscopy (SEM) and the diameter distribution was in the range of 80 to 170 nm. The presence of the enzyme within the PVA nanofibers was confirmed by infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDXS) analyses. The maximum catalytic activity was reached when the enzyme loading was 13%. The immobilization of papain in the nanofiber membrane was achieved by chemical crosslinking with a glutaraldehyde vapor treatment (GAvt). The catalytic activity of the immobilized papain was 88% with respect to the free enzyme. The crosslinking time by GAvt to immobilize the enzyme onto the nanofiber mat was 24 h, and the enzyme retained its catalytic activity after six cycles. The crosslinked samples maintained 40% of their initial activity after being stored for 14 days. PVA electrospun nanofibers are excellent matrices for the immobilization of enzymes due to their high surface area and their nanoporous structure. - Highlights: • Successfully attempt to immobilize the papain enzyme in electrospun nanofibers • The morphology of nanofibers did not change at moderate enzyme concentrations. • The retained activity of the immobilized enzyme was 88% relative to the free enzyme. • The immobilized enzyme retains 40% of the initial activity after 14 days of storage. • Potential application of this work in the fabrication of biosensors specialized in the detection of metal ions.

  9. Encapsulation and immobilization of papain in electrospun nanofibrous membranes of PVA cross-linked with glutaraldehyde vapor

    International Nuclear Information System (INIS)

    Moreno-Cortez, Iván E.; Romero-García, Jorge

    2015-01-01

    In this paper, papain enzyme (E.C. 3.4.22.2, 1.6 U/mg) was successfully immobilized in poly(vinyl alcohol) (PVA) nanofibers prepared by electrospinning. The morphology of the electrospun nanofibers was characterized by scanning electron microscopy (SEM) and the diameter distribution was in the range of 80 to 170 nm. The presence of the enzyme within the PVA nanofibers was confirmed by infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDXS) analyses. The maximum catalytic activity was reached when the enzyme loading was 13%. The immobilization of papain in the nanofiber membrane was achieved by chemical crosslinking with a glutaraldehyde vapor treatment (GAvt). The catalytic activity of the immobilized papain was 88% with respect to the free enzyme. The crosslinking time by GAvt to immobilize the enzyme onto the nanofiber mat was 24 h, and the enzyme retained its catalytic activity after six cycles. The crosslinked samples maintained 40% of their initial activity after being stored for 14 days. PVA electrospun nanofibers are excellent matrices for the immobilization of enzymes due to their high surface area and their nanoporous structure. - Highlights: • Successfully attempt to immobilize the papain enzyme in electrospun nanofibers • The morphology of nanofibers did not change at moderate enzyme concentrations. • The retained activity of the immobilized enzyme was 88% relative to the free enzyme. • The immobilized enzyme retains 40% of the initial activity after 14 days of storage. • Potential application of this work in the fabrication of biosensors specialized in the detection of metal ions

  10. Immobilization of Mucor miehei Lipase onto Macroporous Aminated Polyethersulfone Membrane for Enzymatic Reactions

    NARCIS (Netherlands)

    Handayani, Nurrahmi; Loos, Katja; Wahyuningrum, Deana; Buchari, [No Value; Zulfikar, Muhammad Ali

    2012-01-01

    Immobilization of enzymes is one of the most promising methods in enzyme performance enhancement, including stability, recovery, and reusability. However, investigation of suitable solid support in enzyme immobilization is still a scientific challenge. Polyethersulfone (PES) and aminated PES

  11. Immobilization and release study of a red alga extract in hydrogel membranes

    International Nuclear Information System (INIS)

    Amaral, Renata Hage

    2009-01-01

    In pharmaceutical technology hydrogel is the most used among the polymeric matrices due to its wide application and functionality, primarily in drug delivery system. In view of the large advance innovations in cosmetic products, both through the introduction of new active agents as the matrices used for its controlled release, the objective of this study was to evaluate the release and immobilization of a natural active agent, the Arct'Alg in hydrogel membranes to obtain a release device for cosmetics. Arct'Alg is an aqueous extract which has excellent anti-oxidant, lipolytic, anti-inflammatory and cytostimulant action. Study on mechanical and physical-chemical properties and biocompatibility in vitro of hydrogel membranes of poly(vinyl-2- pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) obtained by ionizing radiation crosslinking have been performed. The physical-chemical characterization of polymeric matrices was carried out by gel fraction and swelling tests and biocompatibility by in vitro test of cytotoxicity by using the technique of neutral red incorporation. In the gel fraction test, both the PVP and PVA hydrogel showed a high crosslinking degree. The PVP hydrogel showed a greater percentage of swelling in relation to PVA and the cytotoxicity test of the hydrogels showed non-toxicity effect. The cytostimulation property of Arct'Alg was verified by the cytostimulation test with rabbit skin cells, it was showed an increase at about 50% of the cells when in contact with 0,5% of active agent. The hydrogel membranes prepared with 3% of Arct'Alg were subjected to the release test in an incubator at 37 degree C and aliquots collected during the test were quantified by high performance liquid chromatography (HPLC). The results obtained in the kinetics of release showed that the PVP hydrogel membranes released about 50% of Arct'Alg incorporated and the PVA hydrogel membranes at about 30%. In the cytostimulation test of released Arct'Alg, the PVP device showed an

  12. Bio-Inspired Assembly of Artificial Photosynthetic Antenna Complexes for Development of Nanobiodevices

    Science.gov (United States)

    2011-06-24

    complexes involved in the primary reactions of bacterial photosynthesis . The structure of the reaction center (RC, the first membrane protein to have its...role in the primary process of purple bacterial photosynthesis that is, capturing light energy, transferring it to the RC where it is used in...immobilization LH2 LH1-RC AFM image of a bacterial photosynthetic membrane . Artificial domains of LH2 & LH1-RC with patterning substrate Modern

  13. The mechanism of anthracene interaction with photosynthetic apparatus: A study using intact cells, thylakoid membranes and PS II complexes isolated from Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Aksmann, Anna; Shutova, Tatiana; Samuelsson, Goeran; Tukaj, Zbigniew

    2011-01-01

    Intact cells of Chlamydomonas reinhardtii as well as isolated thylakoid membranes and photosystem II complexes were used to examine a possible mechanism of anthracene (ANT) interaction with the photosynthetic apparatus. Since ANT concentrations above 1 mM were required to significantly inhibit the rate of oxygen evolution in PS II membrane fragments it may indicate that the toxicant did not directly interact with this photosystem. On the other hand, stimulation of oxygen uptake by ANT-treated thylakoids suggested that ANT could either act as an artificial electron acceptor in the photosynthetic electron transport chain or function as an uncoupler. Electron transfer from excited chlorophyll to ANT is impossible due to the very low reduction potential of ANT and therefore we propose that toxic concentrations of ANT increase the thylakoid membrane permeability and thereby function as an uncoupler, enhancing electron transport in vitro. Hence, its unspecific interference with photosynthetic membranes in vitro suggests that the inhibitory effect observed on intact cell photosynthesis is caused by uncoupling of phosphorylation.

  14. Retention behavior of flavonoids on immobilized artificial membrane chromatography and correlation with cell-based permeability.

    Science.gov (United States)

    Tsopelas, Fotios; Tsagkrasouli, Maria; Poursanidis, Pavlos; Pitsaki, Maria; Vasios, George; Danias, Panagiotis; Panderi, Irene; Tsantili-Kakoulidou, Anna; Giaginis, Constantinos

    2018-03-01

    The aim of the study was to investigate the immobilized artificial membrane (IAM) retention mechanism for a set of flavonoids and to evaluate the potential of IAM chromatography to model Caco-2 permeability. For this purpose, the retention behavior of 41 flavonoid analogs on two IAM stationary phases, IAM.PC.MG and IAM.PC.DD2, was investigated. Correlations between retention factors, logk w(IAM) and octanol-water partitioning (logP) were established and the role of hydroxyl groups of flavonoids to the underlying retention mechanism was explored. IAM retention and logP values were used to establish sound linear models with Caco-2 permeability (logP app ) taken from the literature. Both stepwise regression and multivariate analysis confirmed the contribution of hydrogen bond descriptors, as additional parameters in the either logk w(IAM) or logP models. Retention factors on both IAM stationary phases showed comparable performance with n-octanol-water partitioning towards Caco-2 permeability. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions.

    OpenAIRE

    Højberg, O; Binnerup, S J; Sørensen, J

    1997-01-01

    A technique was developed to study microcolony formation by silicone-immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria. The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a...

  16. Catalytic Activity and Photophysical Properties of Biomolecules Immobilized on Mesoporous Silica

    DEFF Research Database (Denmark)

    Ikemoto, Hideki

    Mesoporous silicas, based on Santa Barbara Amorphous-15 (SBA-15), with different morphology, structure, pore size and functional groups have been synthesized. Two metalloenzymes and a photosynthetic membrane protein were immobilized on or confined in the pores of the mesoporous silicas to prepare...

  17. Synchrotron small-angle x-ray scattering investigation on integral membrane protein light-harvesting complex LH2 from photosynthetic bacterium rhodopseudomonas acidophila

    International Nuclear Information System (INIS)

    Du Luchao; Weng Yuxiang; Hong Xinguo; Xian Dingchang; Kobayashi Katsumi

    2006-01-01

    Structures of membrane protein in solution are different from that in crystal phase. We present the primary results of small angle x-ray scattering (SAXS) resolved topological structures of a light harvesting antenna membrane protein complex LH2 from photosynthetic bacteria Rhodopseudomonas acidophila in detergent solution for the first time. Our results show that the elliptical shape of the LH2 complex in solution clearly deviates from its circular structure in crystal phase determined by x-ray diffraction. This result provides an insight into the structure and function interplay in LH2. (authors)

  18. The potential of immobilized artificial membrane chromatography to predict human oral absorption.

    Science.gov (United States)

    Tsopelas, Fotios; Vallianatou, Theodosia; Tsantili-Kakoulidou, Anna

    2016-01-01

    The potential of immobilized artificial membrane (IAM) chromatography to estimate human oral absorption (%HOA) was investigated. For this purpose, retention indices on IAM stationary phases reported previously by our group or measured by other authors under similar conditions were used to model %HOA data, compiled from literature sources. Considering the pH gradient in gastrointestinal tract, the highest logkw(IAM) values were considered, obtained either at pH7.4 or 5.5, defined as logkw(IAM)(best). Non linear models were established upon introduction of additional parameters and after exclusion of drugs which are substrates either to efflux or uptake transporters. The best model included Abraham's hydrogen-bond acidity parameter, molecular weight as well as the positively and negatively charged molecular fractions. For reasons of comparison between IAM chromatography and traditional lipophilicity, corresponding models were derived by replacing IAM retention factors with octanol-water distribution coefficients (logD). An overexpression of electrostatic interactions with phosphate anions was observed in the case of IAM retention as expressed by the negative contribution of the positively charged fraction F(+). The same parameter is statistically significant also in the logD model, but with a positive sign, indicating the attraction of basic drugs in the negatively charged inner membrane. To validate the obtained models a blind test set of 22 structurally diverse drugs was used, whose logkw(IAM)(best) values were determined and analyzed in the present study under similar conditions. IAM retention factors were further compared with MDCK cell lines permeability data taken from literature for a set of validation drugs. The overexpression of electrostatic interactions with phosphate anions on IAM surface was also evident in respect to MDCK permeability. In contrast to the clear classification between drugs with high and poor (or intermediate) absorption provided by MDCK

  19. The absence of chlorophyll b affects lateral mobility of photosynthetic complexes and lipids in grana membranes of Arabidopsis and barley chlorina mutants.

    Science.gov (United States)

    Tyutereva, Elena V; Evkaikina, Anastasiia I; Ivanova, Alexandra N; Voitsekhovskaja, Olga V

    2017-09-01

    The lateral mobility of integral components of thylakoid membranes, such as plastoquinone, xanthophylls, and pigment-protein complexes, is critical for the maintenance of efficient light harvesting, high rates of linear electron transport, and successful repair of damaged photosystem II (PSII). The packaging of the photosynthetic pigment-protein complexes in the membrane depends on their size and stereometric parameters which in turn depend on the composition of the complexes. Chlorophyll b (Chlb) is an important regulator of antenna size and composition. In this study, the lateral mobility (the mobile fraction size) of pigment-protein complexes and lipids in grana membranes was analyzed in chlorina mutants of Arabidopsis and barley lacking Chlb. In the Arabidopsis ch1-3 mutant, diffusion of membrane lipids decreased as compared to wild-type plants, but the diffusion of photosynthetic complexes was not affected. In the barley chlorina f2 3613 mutant, the diffusion of pigment-protein complexes significantly decreased, while the diffusion of lipids increased, as compared to wild-type plants. We propose that the size of the mobile fractions of pigment-protein complexes in grana membranes in vivo is higher than reported previously. The data are discussed in the context of the protein composition of antennae, characteristics of the plastoquinone pool, and production of reactive oxygen species in leaves of chlorina mutants.

  20. Design of an optically stable pH sensor based on immobilization of Giemsa on triacetylcellulose membrane.

    Science.gov (United States)

    Khodadoust, Saeid; Kouri, Narges Cham; Talebiyanpoor, Mohammad Sharif; Deris, Jamile; Pebdani, Arezou Amiri

    2015-12-01

    In this work a simple, inexpensive, and sensitive optical sensor based on triacetylcellulose membrane as solid support was developed by using immobilization of Giemsa indicator for pH measurement. In this method, the influence variables on the membrane performance including pH concentration of indicator, response time, ionic strength, and reversibility were investigated. At optimum values of all variables the response of optical pH sensor is linear in the pH range of 3.0-12.0. This optical sensor was produced through simultaneous binding of the Giemsa on the activated triacetylcellulose membrane which responded to the pH changes in a broader linear range within less than 2.0 min and suitable reproducibility (RSDsensor was stable after 6 months of storage in the water/ethanol (50:50, v/v) solution without any measurable divergence in response properties (less than 5% RSD). Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Photosynthetic microbial fuel cell with polybenzimidazole membrane: synergy between bacteria and algae for wastewater removal and biorefinery

    Directory of Open Access Journals (Sweden)

    S. Angioni

    2018-03-01

    Full Text Available Here, we demonstrate a very efficient simultaneous approach of bioenergy generation from wastewater and added-value compounds production by using a photosynthetic microalgae microbial fuel cells (PMFC, based on polybenzimidazole (PBI composite membrane as separator. The use of PBI was proved to be very promising, even more convenient than Nafion™ in terms of energy performances as well as cost and sustainability. This polymer is also easily autoclavable, so allowing a re-use of the separator with a consequent beneficial cost effect. Two PMFCs were investigated: 1 Pt electrocatalysed and 2 Pt-free. They were operated as microbial carbon capture (MCC device under continuous illumination, by using a domestic wastewater as anolyte and Scenedesmus acutus strain in the catholyte. The Pt-based cell allowed to generate higher volumetric power density (∼400 mW m−3 after more than 100 operating days. This resulted in an improved wastewater treatment efficiency, determined in terms of normalised energy recovery (NER > 0.19 kWh kgCOD−1 in case of Pt. The CO2 fixation of the PMFC-grown microalgae leaded to a high accumulation of added-value products, namely pigments and fatty acids. A significant quantity of lutein was observed as well as a relevant amount of other valuable carotenoids, as violaxanthin, astaxanthin and cantaxanthin. The lipids were even excellently accumulated (49%dw. Their profile was mainly composed by fatty acids in the range C16-18, which are particularly indicated for the biofuel production. These results demonstrate the feasibility and the implemented sustainability of such PMFCs as a great potential technology for the wastewater treatment and the simultaneous production of valuable products. Keyword: Energy

  2. Effect of enzyme location on activity and stability of trypsin and urease immobilized on porous membranes by using layer-by-layer self-assembly of polyelectrolyte

    OpenAIRE

    Guedidi, Sadika; Yürekli, Yılmaz; Deratani, André; Déjardin, Philippe; Innocent, Christophe; Altınkaya, Sacide; Roudesli, Sadok; Yemenicioğlu, Ahmet

    2010-01-01

    The layer-by-layer (LbL) self-assembly of polyelectrolyte is one of the simplest ways to immobilize enzyme on membrane. In this paper, the immobilization of trypsin (TRY) and urease (URE) on polyacrylonitrile based membranes using the LbL assembly technique was presented. The studied systems consisted in bilayered assemblies with the enzyme layer as the outer layer and trilayered assemblies with the enzyme layer as the inner sandwiched layer. The membrane pore size was chosen so that the smal...

  3. Development of immobilized membrane-based affinity columns for use in the online characterization of membrane bound proteins and for targeted affinity isolations

    International Nuclear Information System (INIS)

    Moaddel, Ruin; Wainer, Irving W.

    2006-01-01

    Membranes obtained from cell lines that express or do not express a target membrane bound protein have been immobilized on a silica-based liquid chromatographic support or on the surface of an activated glass capillary. The resulting chromatographic columns have been placed in liquid chromatographic systems and used to characterize the target proteins and to identify small molecules that bind to the target. Membranes containing ligand gated ion channels, G-protein coupled receptors and drug transporters have been prepared and characterized. If a marker ligand has been identified for the target protein, frontal or zonal displacement chromatographic techniques can be used to determine binding affinities (K d values) and non-linear chromatography can be used to assess the association (k on ) and dissociation (k off ) rate constants and the thermodynamics of the binding process. Membrane-based affinity columns have been created using membranes from a cell line that does not express the target protein (control) and the same cell line that expresses the target protein (experimental) after genomic transfection. The resulting columns can be placed in a parallel chromatography system and the differential retention between the control and experimental columns can be used to identify small molecules and protein that bind to the target protein. These applications will be illustrated using columns created using cellular membranes containing nicotinic acetylcholine receptors and the drug transporter P-glycoprotein

  4. Development of immobilized membrane-based affinity columns for use in the online characterization of membrane bound proteins and for targeted affinity isolations

    Energy Technology Data Exchange (ETDEWEB)

    Moaddel, Ruin [Gerontology Research Center, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825 (United States); Wainer, Irving W. [Gerontology Research Center, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825 (United States)]. E-mail: Wainerir@grc.nia.nih.gov

    2006-03-30

    Membranes obtained from cell lines that express or do not express a target membrane bound protein have been immobilized on a silica-based liquid chromatographic support or on the surface of an activated glass capillary. The resulting chromatographic columns have been placed in liquid chromatographic systems and used to characterize the target proteins and to identify small molecules that bind to the target. Membranes containing ligand gated ion channels, G-protein coupled receptors and drug transporters have been prepared and characterized. If a marker ligand has been identified for the target protein, frontal or zonal displacement chromatographic techniques can be used to determine binding affinities (K {sub d} values) and non-linear chromatography can be used to assess the association (k {sub on}) and dissociation (k {sub off}) rate constants and the thermodynamics of the binding process. Membrane-based affinity columns have been created using membranes from a cell line that does not express the target protein (control) and the same cell line that expresses the target protein (experimental) after genomic transfection. The resulting columns can be placed in a parallel chromatography system and the differential retention between the control and experimental columns can be used to identify small molecules and protein that bind to the target protein. These applications will be illustrated using columns created using cellular membranes containing nicotinic acetylcholine receptors and the drug transporter P-glycoprotein.

  5. Stability of integral membrane proteins under high hydrostatic pressure: the LH2 and LH3 antenna pigment-protein complexes from photosynthetic bacteria.

    Science.gov (United States)

    Kangur, Liina; Timpmann, Kõu; Freiberg, Arvi

    2008-07-03

    The bacteriochlorophyll a-containing LH2 and LH3 antenna complexes are the integral membrane proteins that catalyze the photosynthetic process in purple photosynthetic bacteria. The LH2 complex from Rhodobacter sphaeroides shows characteristic strong absorbance at 800 and 850 nm due to the pigment molecules confined in two separate areas of the protein. In the LH3 complex from Rhodopesudomonas acidophila the corresponding bands peak at 800 and 820 nm. Using the bacteriochlorophyll a cofactors as intrinsic probes to monitor local changes in the protein structure, we investigate spectral responses of the antenna complexes to very high hydrostatic pressures up to 2.5 GPa when embedded into natural membrane environment or extracted with detergent. We first demonstrate that high pressure does induce significant alterations to the tertiary structure of the proteins not only in proximity of the 800 nm-absorbing bacteriochlorophyll a molecules known previously (Gall, A.; et al. Biochemistry 2003, 42, 13019) but also of the 850 nm- and 820 nm-absorbing molecules, including breakage of the hydrogen bond they are involved in. The membrane-protected complexes appear more resilient to damaging effects of the compression compared with the complexes extracted into mixed detergent-buffer environment. Increased resistance of the isolated complexes is observed at high protein concentration resulting aggregation as well as when cosolvent (glycerol) is added into the solution. These stability variations correlate with ability of penetration of the surrounding polar solvent (water) into the hydrophobic protein interiors, being thus the principal reason of the pressure-induced denaturation of the proteins. Considerable variability of elastic properties of the isolated complexes was also observed, tentatively assigned to heterogeneous protein packing in detergent micelles. While a number of the isolated complexes release most of their bacteriochlorophyll a content under high pressure

  6. Spontaneous stacking of purple membranes during immobilization with physical cross-linked poly(vinyl alcohol) hydrogel with retaining native-like functionality of bacteriorhodopsin

    Science.gov (United States)

    Yokoyama, Yasunori; Tanaka, Hikaru; Yano, Shunsuke; Takahashi, Hiroshi; Kikukawa, Takashi; Sonoyama, Masashi; Takenaka, Koshi

    2017-05-01

    We previously discovered the correlation between light-induced chromophore color change of a photo-receptor membrane protein bacteriorhodopsin (bR) and its two-dimensional crystalline state in the membrane. To apply this phenomenon to a novel optical memory device, it is necessary that bR molecules are immobilized as maintaining their structure and functional properties. In this work, a poly(vinyl alcohol) (PVA) hydrogel with physical cross-linkages (hydrogen bonds between PVA chains) that resulted from repeated freezing-and-thawing (FT) cycles was used as an immobilization medium. To investigate the effects of physically cross-linked PVA gelation on the structure and function of bR in purple membranes (PMs), spectroscopic techniques were employed against PM/PVA immobilized samples prepared with different FT cycle numbers. Visible circular dichroism spectroscopy strongly suggested PM stacking during gelation. X-ray diffraction data also indicated the PM stacking as well as its native-like crystalline lattice even after gelation. Time-resolved absorption spectroscopy showed that bR photocycle behaviors in PM/PVA immobilized samples were almost identical to that in suspension. These results suggested that a physically cross-linked PVA hydrogel is appropriate for immobilizing membrane proteins in terms of maintaining their structure and functionality.

  7. IMMOBILIZATION OF FLAVIN ON HIGHLY POROUS POLYMERIC DISKS - 3 ROUTES TO A CATALYTICALLY ACTIVE MEMBRANE

    NARCIS (Netherlands)

    SCHOO, HFM; CHALLA, G; ROWATT, B; SHERRINGTON, DC

    Disks obtained by polymerization of high internal phase emulsions (Polyhipe) had completely open pore structures and were used as a carrier material for the immobilisation of 10-ethyl-isoalloxazine ('flavin'). Three methods for immobilization are described: (1) direct modification of

  8. SYNTHESIS, CHARACTERIZATION AND APPLICATION OF A POLYURETHANE-BASED SUPPORT FOR IMMOBILIZING MEMBRANE-BOUND LIPASE

    Directory of Open Access Journals (Sweden)

    M. S. Soares

    Full Text Available Abstract This study conducted an assessment of polyurethane foams that were synthesized by one-shot process and used as a low-cost support to immobilize Mucor circinelloides URM 4182 whole-cells presenting high lipolytic activity. Polyols with different molecular weights (1100 to 6000 g mol-1 were applied to synthesize the polymer matrix, and the agitation speed effect was used for controlling the average pore size of the investigated polyurethane foams. The physical and mechanical properties of the polymers were evaluated by standard test methods, and their morphology was identified by Scanning Electron Microscopy. The immobilization procedure efficiency was assessed by quantifying the capability of the matrices to attach the cells and the catalytic activity of the biocatalysts in both aqueous (olive oil hydrolysis and non-aqueous media (ethanolysis of babassu oil under single and consecutive batch runs. Although all synthesized matrices were suitable to immobilize the whole cells with high catalytic performance, a better set of parameters was attained when the polyol ether with molecular weight of 6000 g mol-1 and 1100 g mol-1 was used. Both matrices yielded immobilized biocatalysts with high hydrolysis and transesterification activities, and exhibited a satisfactory operational stability with 96% and 81% retention of their initial hydrolytic and transesterification activities after three consecutive batch runs.

  9. Polymer-immobilized liquid membrane transport of palladium (II) from nitric acid media using some thia extractants as novel receptors

    International Nuclear Information System (INIS)

    Shukla, J.P.

    1996-01-01

    Carrier-facilitated co-transport of Pd (II) from dilute acidic nitrate solutions was examined across a polymer-immobilized liquid membrane (PILM) deploying S 6 -pentano-36 (S 6 -P-36), bis-(2-ethylhexyl) sulfoxide (BESO) and bis (2, 4, 4 trimethyl pentyl) monothio phosphinic acid (Cyanex 302) as the novel receptors. The study carried out to distinguish the driving force between H + and NO 3 - ion for the cation transport across PILM, indicated that NO 3 - ion not the H + ion seems to be the driving force for Pd (II) transport under the present conditions for both BESO-PILM and S 6 -P-36-PILM systems. Recovery of palladium from acidic process effluents generated in Purex reprocessing of spent fuels was successfully achieved. 39 refs., 8 figs., 7 tabs

  10. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

    1997-01-01

    A technique was developed to study microcolony formation by silicone- immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria....... The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a sudden lack of oxygen. In contrast, nitrate-respiring, fermenting bacteria, e.g., Bacillus and Escherichia...... spp, formed microcolonies under anaerobic conditions with or without the presence of nitrate and irrespective of aerobic or anaerobic preculture conditions....

  11. Immobilization of tris(2 pyridyl methylamine in a PVC-Membrane Sensor and Characterization of the Membrane Properties

    Directory of Open Access Journals (Sweden)

    Rezayi Majid

    2012-05-01

    Full Text Available Abstract Background Due to the increasing industrial use of titanium compounds, its determination is the subject of considerable efforts. The ionophore or membrane active recognition is the most important component of any polymeric membrane sensor. The sensor’s response depends on the ionophore and bonding between the ionophore and the target ion. Ionophores with molecule-sized dimensions containing cavities or semi-cavities can surround the target ion. The bond between the ionophore and target ion gives different selectivity and sensitivity toward the other ions. Therefore, ionophores with different binding strengths can be used in the sensor. Results In the present work, poly (vinyl chloride (PVC based membrane incorporating tris (2 pyridyl methylamine (tpm as an ionophore has been prepared and explored as a titanium(III selective sensor. Conclusions The strengths of the ion–ionophore (Ti(OH2+-tpm interactions and the role of ionophore on membrane were tested by various techniques such as elemental analysis, UV–vis, Fourier transform infrared (FTIR spectroscopy, scanning electron microscopy (SEM, and powder X-ray diffraction (XRD. All data approved the successful incorporation of organic group via covalent bond.

  12. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization.

    Science.gov (United States)

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao

    2014-12-10

    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  13. Immobilization of nanoparticle titanium dioxide membrane on polyamide fabric by low temperature hydrothermal method

    International Nuclear Information System (INIS)

    Zhang Hui; Yang Lu

    2012-01-01

    A thin layer of nanoparticle titanium dioxide was immobilized on polyamide 6 (PA6) fiber using titanium sulfate and urea at low temperature hydrothermal condition. The titanium dioxide loaded fabric was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetry techniques. The optical and mechanical properties, water absorption and degradation of methylene blue dye under ultraviolet (UV) irradiation of the PA6 fabric before and after treatments were also examined. It was found that when PA6 fabric was treated in titanium sulfate and urea aqueous solution, anatase nanocrystalline titanium dioxide was synthesized and simultaneously adhered onto the fiber surface. The average crystal size of titanium dioxide nanoparticles was about 13.2 nm. The thermal behavior of PA6 fiber distinctly changed and the onset decomposition temperature decreased. As compared with the untreated fabric, the protection against UV radiation was improved. The water absorbency increased slightly. As the fabric dimensions were reduced in warp and weft directions, the breaking load and tensile strain increased to some extent. The titanium dioxide coated fabric could degradate methylene blue dye under UV irradiation. - Highlights: ► We employed a method to immobilize TiO 2 nanoparticle on polyamide fiber. ► We fabricated the TiO 2 -coated polyamide fabric with the photocatalytic activity. ► The modification method may be suitable for the potential applications.

  14. Development of a novel pH sensor based upon Janus Green B immobilized on triacetyl cellulose membrane: Experimental design and optimization

    Science.gov (United States)

    Chamkouri, Narges; Niazi, Ali; Zare-Shahabadi, Vali

    2016-03-01

    A novel pH optical sensor was prepared by immobilizing an azo dye called Janus Green B on the triacetylcellulose membrane. Condition of the dye solution used in the immobilization step, including concentration of the dye, pH, and duration were considered and optimized using the Box-Behnken design. The proposed sensor showed good behavior and precision (RSD < 5%) in the pH range of 2.0-10.0. Advantages of this optical sensor include on-line applicability, no leakage, long-term stability (more than 6 months), fast response time (less than 1 min), high selectivity and sensitivity as well as good reversibility and reproducibility.

  15. Novel Approaches to Immobilized Heteropoly Acid Systems for High Temperature, Low Relative Humidity Polymer-Type Membranes - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Herring, Andrew M; Horan, James L; Aieta, Niccolo V; Sachdeva, Sonny; Kuo, Mei-Chen; Ren, Hui; Lingutla, Anitha; Emery, Michael; Haugen, Gregory M; Yandrasits, Michael A; Sharma, Neeraj; Coggio, William D; Hamrock, Steven J; Frey, Matthew H

    2012-05-20

    Original research was carried out at the CSM and the 3M Company from March 2007 through September 2011. The research was aimed at developing new to the world proton electrolyte materials for use in hydrogen fuel cells, in particular with high proton conductivity under hot and dry conditions (>100mS/cm at 120°C and 50%RH). Broadly stated, the research at 3M and between 3M and CSM that led to new materials took place in two phases: In the first phase, hydrocarbon membranes that could be formed by photopolymerization of monomer mixtures were developed for the purpose of determining the technical feasibility of achieving the program's Go/No-Go decision conductivity target of >100mS/cm at 120°C and 50%RH. In the second phase, attempts were made to extend the achieved conductivity level to fluorinated material systems with the expectation that durability and stability would be improved (over the hydrocarbon material). Highlights included: Multiple lots of an HPA-immobilized photocurable terpolymer derived from di-vinyl-silicotungstic acid (85%), n-butyl acrylate, and hexanediol diacrylate were prepared at 3M and characterized at 3M to exhibit an initial conductivity of 107mS/cm at 120°C and 47%RH (PolyPOM85v) using a Bekktech LLC sample fixture and TestEquity oven. Later independent testing by Bekktech LLC, using a different preheating protocol, on the same material, yielded a conductivity value of approximately 20mS/cm at 120°C and 50%RH. The difference in measured values is likely to have been the result of an instability of properties for the material or a difference in the measurement method. A dispersed catalyst fuel cell was fabricated and tested using a 150¼m thick HPA-based photocurable membrane (above, PolyPOM75v), exhibiting a current density of greater than 300mA/cm2 at 0.5V (H2/Air 800/1800sccm 70°C/75%RH ambient outlet pressure). Multiple lots of a co-polymer based on poly-trifluorovinylether (TFVE) derived HPA were synthesized and fabricated into

  16. Development of glucose biosensor based on ZnO nanoparticles film and glucose oxidase-immobilized eggshell membrane

    Directory of Open Access Journals (Sweden)

    Bohari Noor Aini

    2015-06-01

    Full Text Available A novel electrochemical glucose biosensor was developed by depositing an ionic liquid (IL (e.g., 1-ethyl-3-methylimidazolium trifluoromethanesulfonate; [EMIM][Otf], ZnO nanoparticles (ZnONPs and eggshell membrane (ESM on a modified glassy carbon electrode (GCE for determination of glucose. Glucose oxidase (GOx was covalently immobilized on eggshell membrane with glutaraldehyde as a cross-linker. Methylene blue was used as a redox indicator to enhance the electron transfer capacity and to ensure stability of both the oxidized and reduced forms in the reaction of enzyme and substrate. The morphological characteristics of microstructures eggshell membranes, chitosan, GOx/ESM, GOx/ZnONPs/IL/ESM and GOx/ZnONPs-IL/CHIT were observed using scanning electron microscopy (SEM. The effects of scan rate, time and pH on the response of glucose biosensors were studied in detail. Under optimal conditions (pH 6.5, 50 s, cyclic voltammetry showed different glucose concentrations on the range of 1 × 10−12 to 0.6 M, with a detection limit of 1 × 10−13 M. The GOx/ZnONPs/IL/ESM was found to be more sensitive as compared to GOx/ZnONPs-IL/CHIT. This developed glucose biosensor detection approach has several advantages such as fast, simple and convenient method, sensitivity, low cost, eco-friendly, low concentrations and remarkable catalytic activities of current signals during glucose reaction.

  17. Sorption Behavior of CO2 and CH4 of Glassy Polymeric Membranes and Analytical Discussion of Partial Immobilization Model

    Directory of Open Access Journals (Sweden)

    M. Mahdavian

    2007-06-01

    Full Text Available Among various reported membrane-based gas separation processes, the best explanation is generally achieved by the solution-diffusion model. The main factors in this model are the solubility and diffusivity of permeationcomponents through the membrane. The prediction of permeability and diffusivity in multicomponent gas permeation as well as the separation evaluation equilibrium and kinetic interactions requires a proper explanation of sorption and diffusion phenomena in the polymer matrix. Investigation made by various researchers in this area shows that the equilibrium interaction (sorption step plays the key role in determining diffusion and permeation in multicomponent system. Therefore, the proper description of sorption behaviour of gas mixture in the polymer is an essential task. The dual-mode sorption (Langmuir-Henry is usually used for the description of equilibrium isotherm of gases in glassy polymers based on this model; the diffusive behaviour of the system is subsequently analyzed by the partial immobilization model. In this study, the equilibrium sorption of CO2/CH4 mixture in various polymers was modelled using the experimental data available in the literature. The differences in the mechanism of adsorption for CO2 and CH4 were analyzed by considering variations in mode of sorption for each adsorbed component at different pressures. By introducing a new adsorption parameter, P50/50, (the pressure at which the portion of two modes in sorption are equal the contribution of each adsorbed component in occupying Langmuir sites was evaluated. The results indicate that the relative significance of sorption mode for each component is a function of pressure and it is different for various polymers.

  18. Tracing of backward energy transfer from LH1 to LH2 in photosynthetic membranes grown under high and low irradiation.

    Directory of Open Access Journals (Sweden)

    Lanzani G.

    2013-03-01

    Full Text Available By introducing derivative transient absorption spectroscopy, we obtain rate constants for backward and forward energy transfer between LH1 and LH2 complexes in purple bacterial membranes. We find that backward energy transfer is strongly reduced in membranes grown under low irradiation conditions, compared to high light grown ones. We conclude that backward energy transfer is managed actively by the bacteria to avoid LH1 exciton deactivation under high irradiation conditions. The analytical method is generally applicable to excitonically coupled systems.

  19. Enzyme Immobilization on Inorganic Surfaces for Membrane Reactor Applications: Mass Transfer Challenges, Enzyme Leakage and Reuse of Materials

    DEFF Research Database (Denmark)

    Sigurdardóttir, Sigyn Björk; Lehmann, Jonas; Ovtar, Simona

    2018-01-01

    Enzyme immobilization is an established method for the enhancement of enzyme stability and reusability, two factors that are of great importance for industrial biocatalytic applications. Immobilization can be achieved by different methods and on a variety of carrier materials, both organic and in...

  20. Bioengineering of photosynthetic membranes. Requirement of magnesium for the conversion of chlorophyllide a to chlorophyll a during the greening of etiochloroplasts in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Daniell, H.; Rebeiz, C.A.

    1984-01-01

    The massive conversion of delta-aminolevulinic acid (ALA) to protochlorophyllide (Pchlide) and the massive conversion of chlorophyllide a (Chlide a) to chlorophyll a (Chl a) are two essential conditions for the ALA-dependent assembly of photosynthetic membranes in vitro. In this work, the authors describe the development of a cell-free system capable of the forementioned biosynthetic activities at rates higher than in vivo, for the first 2 h of dark-incubation. The cell-free system consisted of 1) etiochloroplasts prepared from kinetin and gibberellic-acid-pretreated cucumber cotyledons, and 2) cofactors and additives described elsewhere and which are needed for the massive conversion of ALA to Pchlide, 3) high concentrations of ATP, MgCl/sub 2/, and an isoprenol alcohol such as phytol, were required for the massive conversion of Chlide a to Chl a. An absolute and novel requirement of Mg/sup 2 +/ for the conversion of Chlide a to Chl a was also demonstrated. In addition to the role of phytol as a substrate for the conversion of Chlide a to Chl a, the data suggested that this alcohol may also be involved in the regulation of the reactions between ALA and Pchlide. It is proposed that during greening, the conversion of Chlide a to Chl a may follow different biosynthetic rates, having different substrate and cofactor requirements, depending on the stage of plastid development.

  1. Comparison of TEVAR resin beads, PAN fibers, and ePTFE membranes as a solid support for Aliquat-336 in immobilized liquid extraction chromatography for separation of actinides

    International Nuclear Information System (INIS)

    Joe Dauner; Steve Workman

    2012-01-01

    The following paper covers a comparison of two new systems to traditional TEVA R resin systems for the analytical separation of actinides by immobilized liquid-liquid extraction using Aliquat-336. The new systems are using expanded polytetrafluroethane (ePTFE) membrane or polyacrylonitrile (PAN) fibers as the solid support. The systems are compared in two ways. First in how much Aliquat-336 they contain with the Vs, ratio of volume of Aliquat-336 to volume of polymeric support, being 0.158, 0.483, and 0.590 for the TEVA R resin, PAN fibers, and the ePTFE systems, respectively. The second comparison is in their performance capacity of extraction of uranyl chloride anion complex. The fiber and resins systems show similar capacities, and the membrane system being an order of magnitude less than the other systems. A cost comparison demonstrates the savings advantages of using a fiber based support compared with resin and membrane support systems. (author)

  2. Development of a novel pH sensor based upon Janus Green B immobilized on triacetyl cellulose membrane: Experimental design and optimization.

    Science.gov (United States)

    Chamkouri, Narges; Niazi, Ali; Zare-Shahabadi, Vali

    2016-03-05

    A novel pH optical sensor was prepared by immobilizing an azo dye called Janus Green B on the triacetylcellulose membrane. Condition of the dye solution used in the immobilization step, including concentration of the dye, pH, and duration were considered and optimized using the Box-Behnken design. The proposed sensor showed good behavior and precision (RSDpH range of 2.0-10.0. Advantages of this optical sensor include on-line applicability, no leakage, long-term stability (more than 6 months), fast response time (less than 1 min), high selectivity and sensitivity as well as good reversibility and reproducibility. Copyright © 2015. Published by Elsevier B.V.

  3. Fabrication of palladium nanoparticles immobilized on an amine-functionalized ceramic membrane support using a nanoparticulate colloidal impregnation method with enhanced catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yan; Chen, Rizhi [Nanjing Tech University, Nanjing (China)

    2015-09-15

    An efficient and reusable catalyst was developed by depositing palladium nanoparticles on an amine-functionalized ceramic membrane support using a nanoparticulate colloidal impregnation method. The as-prepared Pdloaded ceramic membrane support was characterized by XRD, SEM, EDS, TEM, XPS, ICP, and its catalytic properties were investigated in the liquid-phase p-nitrophenol hydrogenation. A comparative study was also made with the palladium nanoparticles deposited on an amine-functionalized ceramic membrane support by an impregnation-reduction method. The palladium nanoparticles could be homogeneously immobilized on the ceramic membrane support surface, and exhibited excellent catalytic performance in the p-nitrophenol hydrogenation. The catalytic activity of the Pdloaded ceramic membrane support prepared by the nanoparticulate colloidal impregnation method increased by 16.6% compared to that of impregnation-reduction method. In the nanoparticulate colloidal impregnation method, palladium nanoparticles were presynthesized, higher loading of Pd(0) could be obtained, resulting in better catalytic activity. The as-prepared Pd-loaded ceramic membrane support could be easily reused for several cycles without appreciable degradation of catalytic activity.

  4. Deferoxamine immobilized poly(D,L-lactide) membrane via polydopamine adhesive coating: The influence on mouse embryo osteoblast precursor cells and human umbilical vein endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huihua [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Luo, Binghong, E-mail: tluobh@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Wen, Wei [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Tian, Lingling [Center for Nanofibers & Nanotechnology, Department of Mechanical Engineering, National University of Singapore, Singapore 117576 (Singapore); Ramakrishna, Seeram [Center for Nanofibers & Nanotechnology, Department of Mechanical Engineering, National University of Singapore, Singapore 117576 (Singapore); Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou 510632 (China)

    2017-01-01

    Osteogenesis and angiogenesis play the prominent role in the bone regeneration. In this study, deferoxamine (DFO), an induced agent for osteogenesis and angiogenesis, was modified onto the surface of poly(D,L-lactide) (PDLLA) membrane via a facile and convenient approach based on the self-polymerization of dopamine (DOPA). The surface composition, morphology, hydrophilicity and surface energy of the original and modified PDLLA membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electronic microscopy (SEM), atomic force microscopy (AFM) and contact angle measurement. The surface roughness and hydrophilicity of the PDLLA membrane were obviously increased by introducing either the single polydopamine (PDOPA) or the dual layers of PDOPA and DFO. In vitro cells culture experiments indicated that both the PDLLA/PDOPA and PDLLA/PDOPA-DFO composite membranes were more beneficial to the attachment, proliferation and spreading of MC3T3-E1 cells and HUVECs compared to the original PDLLA membrane. The PDLLA/PDOPA-DFO membrane was supportive for the proliferation of both MC3T3-E1 cells and HUVECs, and especially for HUVECs. The results suggested that the as-prepared PDLLA/PDOPA-DFO composite can be expected to be used as a promising bone regenerative material with promoted angiogenesis. - Highlights: • DFO was conveniently immobilized on PDLLA membrane based on PDOPA adhesive layer. • Hydrophilicity of PDLLA membrane was improved by modification with PDOPA and DFO. • Modified membranes were more favorable to the growth of MC3T3-E1 cells and HUVECs. • DFO was supportive for the growth of two kinds of cells, especially for HUVECs.

  5. Development of a D-amino acids electrochemical sensor based on immobilization of thermostable D-Proline dehydrogenase within agar gel membrane

    International Nuclear Information System (INIS)

    Tani, Yuji; Tanaka, Katsuhito; Yabutani, Tomoki; Mishima, Yuji; Sakuraba, Haruhiko; Ohshima, Toshihisa; Motonaka, Junko

    2008-01-01

    A novel biosensor for determination of D-amino acids (DAAs) in biological samples by using an electrode based on immobilization of a thermostable D-Proline dehydrogenase (D-Pro DH) within an agar gel membrane was developed. The electrode was simply prepared by spin-coating the agar solution with the D-Pro DH on a glassy carbon (GC) electrode. An electrocatalytic oxidation current of 2,6-dichloroindophenol (DCIP) was observed at -100 mV vs. Ag/AgCl with the addition of 5 and 20 mmol L -1 D-proline. The current response and its relative standard deviation were 0.15 μA and 7.6% (n = 3), respectively, when it was measured in a pH 8.0 phosphate buffer solution containing 10 mmol L -1 D-proline and 0.5 mmol L -1 DCIP at 50 deg. C. The current response of D-proline increased with increase of the temperature of the sample solution up to 70 deg. C. The electrocatalytic response at the D-Pro DH/agar immobilized electrode subsequently maintained for 80 days. Finally, the D-Pro DH/agar immobilized electrode was applied to determination of DAAs in a human urine sample. The determined value of DAAs in the human urine and its R.S.D. were 1.39 ± 0.12 mmol L -1 and 8.9% (n = 3), respectively

  6. Immobilization and characterization of inulinase from Ulocladium

    Indian Academy of Sciences (India)

    Ulocladium atrum inulinase was immobilized on different composite membranes composed of chitosan/nonwoven fabrics. Km values of free and immobilized U. atrum inulinase on different composite membranes were calculated. The enzyme had optimum pH at 5.6 for free and immobilized U. atrum inulinase on polyester ...

  7. Activities of lectins and their immobilized derivatives in detergent solutions. Implications on the use of lectin affinity chromatography for the purification of membrane glycoproteins.

    Science.gov (United States)

    Lotan, R; Beattie, G; Hubbell, W; Nicolson, G L

    1977-05-03

    The effects of several commonly used detergents on the saccharide-binding activities of lectins were investigated using lectin-mediated agglutination of formalin-fixed erythrocytes and affinity chromatography of glycoproteins on columns of lectins immobilized on polyacrylic hydrazide-Sepharose. In the hemagglutination assays, Ricinus communis I (RCA1) and II (RCAII), concanavalin A (Con A), and the agglutinins from peanut (PNA), soybean (SBA), wheat germ (WGA), and Limulus polyphemus (LPA) were tested with several concentrations of switterionic, cationic, anionic, and nonionic detergents. It was found that increasing detergent concentrations eventually affected hemagglutination titers in both test and control samples, and the highest detergent concentrations not affecting lectin hemagglutinating activities were determined. The effects of detergents on specific binding of [3H]fetuin and asialo[3H]fetuin to and elution from columns of immobilized lectins were less severe when compared with lectins in solution, suggesting that the lectins are stabilized by covalent attachment to agarose beads. Nonionic detergents did not affect the binding efficiency of the immobilized lectins tested at concentrations used for membrane solubilization while cationic and zwitterionic detergents caused significant inhibition of Con A- and SBA-Sepharose activities. In sodium deoxycholate (greater than 1%) only RCAI-Sepharose retained its activity, whereas the activities of the other lectins were reduced dramatically. Low concentrations of sodium dodecyl sulfate (0.05%) inhibited only the activity of immobilized SBA, but at higher concentration (0.1%) and prolonged periods of incubation (16 h, 23 degrees C) most of the lectins were inactivated. These data are compared with previous reports on the use of detergents in lectin affinity chromatography, and the conditions for the optimal use of detergents are detailed.

  8. Highly selective and sensitive optical sensor for determination of Pb2+and Hg2+ ions based on the covalent immobilization of dithizone on agarose membrane

    Science.gov (United States)

    Zargoosh, Kiomars; Babadi, Fatemeh Farhadian

    2015-02-01

    A highly sensitive and selective optical membrane for determination of Hg2+ and Pb2+ was prepared by covalent immobilization of dithizone on agarose membrane. In addition to its high stability, reproducibility and relatively long lifetime, the proposed optical sensor revealed good selectivity for target ions over a large number of alkali, alkaline earth, transition, and heavy metal ions. The proposed optical membrane displays linear responses from 1.1 × 10-8 to 2.0 × 10-6 mol L-1 and 1.2 × 10-8 to 2.4 × 10-6 mol L-1 for Hg2+ and Pb2+, respectively. The limits of detection (LOD) were 2.0 × 10-9 mol L-1 and 4.0 × 10-9 mol L-1 for Hg2+ and Pb2, respectively. The prepared optical membrane was successfully applied to the determination of Hg2+ and Pb2+ in industrial wastes, spiked tap water and natural waters without any preconcentration step.

  9. Hybrid system of semiconductor and photosynthetic protein

    International Nuclear Information System (INIS)

    Kim, Younghye; Shin, Seon Ae; Lee, Jaehun; Yang, Ki Dong; Nam, Ki Tae

    2014-01-01

    Photosynthetic protein has the potential to be a new attractive material for solar energy absorption and conversion. The development of semiconductor/photosynthetic protein hybrids is an example of recent progress toward efficient, clean and nanostructured photoelectric systems. In the review, two biohybrid systems interacting through different communicating methods are addressed: (1) a photosynthetic protein immobilized semiconductor electrode operating via electron transfer and (2) a hybrid of semiconductor quantum dots and photosynthetic protein operating via energy transfer. The proper selection of materials and functional and structural modification of the components and optimal conjugation between them are the main issues discussed in the review. In conclusion, we propose the direction of future biohybrid systems for solar energy conversion systems, optical biosensors and photoelectric devices. (topical reviews)

  10. Impact of Membrane-Induced Particle Immobilization on Seeded Growth Monitored by In Situ Liquid Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Weiner, Rebecca G; Chen, Dennis P; Unocic, Raymond R; Skrabalak, Sara E

    2016-05-01

    In situ liquid cell scanning transmission electron microscopy probes seeded growth in real time. The growth of Pd on Au nanocubes is monitored as a model system to compare growth within a liquid cell and traditional colloidal synthesis. Different growth patterns are observed due to seed immobilization and the highly reducing environment within the liquid cell. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Terbutaline causes immobilization of single β2-adrenergic receptor-ligand complexes in the plasma membrane of living A549 cells as revealed by single-molecule microscopy

    Science.gov (United States)

    Sieben, Anne; Kaminski, Tim; Kubitscheck, Ulrich; Häberlein, Hanns

    2011-02-01

    G-protein-coupled receptors are important targets for various drugs. After signal transduction, regulatory processes, such as receptor desensitization and internalization, change the lateral receptor mobility. In order to study the lateral diffusion of β2-adrenergic receptors (β2AR) complexed with fluorescently labeled noradrenaline (Alexa-NA) in plasma membranes of A549 cells, trajectories of single receptor-ligand complexes were monitored using single-particle tracking. We found that a fraction of 18% of all β2ARs are constitutively immobile. About 2/3 of the β2ARs moved with a diffusion constant of D2 = 0.03+/-0.001 μm2/s and about 17% were diffusing five-fold faster (D3 = 0.15+/-0.02 μm2/s). The mobile receptors moved within restricted domains and also showed a discontinuous diffusion behavior. Analysis of the trajectory lengths revealed two different binding durations with τ1 = 77+/-1 ms and τ2 = 388+/-11 ms. Agonistic stimulation of the β2AR-Alexa-NA complexes with 1 μM terbutaline caused immobilization of almost 50% of the receptors within 35 min. Simultaneously, the mean area covered by the mobile receptors decreased significantly. Thus, we demonstrated that agonistic stimulation followed by cell regulatory processes results in a change in β2AR mobility suggesting that different receptor dynamics characterize different receptor states.

  12. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Y. F. Huang

    2017-01-01

    Full Text Available Polymer electrolyte membranes (PEMs are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate ester-functionalized small molecules as well as structural properties of polymer nanocomposite, a strategy of immobilizing as-synthesized polyethylene glycol-borate ester/lithium fluoride (B-PEG/LiF in graphene oxide/poly(vinyl alcohol (GO/PVA to prepare a PEM is put forward. Chemical structure of the PEM is firstly characterized by 1H-, 11B- and 19F-nuclear magnetic resonance spectra, and Fourier transform infrared spectroscopy spectra, respectively, and then is further investigated under consideration of the interactions among PVA, B-PEG and LiF components. The immobilization of B-PEG/LiF in PVA-based structure is confirmed. As the interactions within electrolyte components can be further tuned by GO, ionic conductivity (~10–3 S·cm–1, lithium-ion transfer number (~0.49, and thermal (~273 °C/electrochemical (>4 V stabilities of the PEM can be obtained, and the feasibility of PEMs applied in a lithium-ion battery is also confirmed. It is believed that such PEM is a promising candidate as a new battery separator.

  13. Nanodiscs for immobilization of lipid bilayers and membrane receptors: kinetic analysis of cholera toxin binding to a glycolipid receptor

    DEFF Research Database (Denmark)

    Borch, Jonas; Torta, Federico; Sligar, Stephen G

    2008-01-01

    nanodiscs and their incorporated membrane receptors can be attached to surface plasmon resonance sensorchips and used to measure the kinetics of the interaction between soluble molecules and membrane receptors inserted in the bilayer of nanodiscs. Cholera toxin and its glycolipid receptor G(M1) constitute...... a system that can be considered a paradigm for interactions of soluble proteins with membrane receptors. In this work, we have investigated different technologies for capturing nanodiscs containing the glycolipid receptor G(M1) in lipid bilayers, enabling measurements of binding of its soluble interaction...

  14. Large-scale analysis of in Vivo phosphorylated membrane proteins by immobilized metal ion affinity chromatography and mass spectrometry

    DEFF Research Database (Denmark)

    Nühse, Thomas S; Stensballe, Allan; Jensen, Ole N

    2003-01-01

    specificity. We investigated the potential of IMAC in combination with capillary liquid chromatography coupled to tandem mass spectrometry for the identification of plasma membrane phosphoproteins of Arabidopsis. Without chemical modification of peptides, over 75% pure phosphopeptides were isolated from...... plasma membrane digests and detected and sequenced by mass spectrometry. We present a scheme for two-dimensional peptide separation using strong anion exchange chromatography prior to IMAC that both decreases the complexity of IMAC-purified phosphopeptides and yields a far greater coverage...... of monophosphorylated peptides. Among the identified sequences, six originated from different isoforms of the plasma membrane H(+)-ATPase and defined two previously unknown phosphorylation sites at the regulatory C terminus. The potential for large-scale identification of phosphorylation sites on plasma membrane...

  15. Assay of hybrid ribonuclease using a membrane filter-immobilized synthetic hybrid: application to the human leukemic cell

    International Nuclear Information System (INIS)

    Papaphilis, A.D.; Kamper, E.F.

    1985-01-01

    A method for assaying hybrid ribonuclease has been devised which utilizes as substrate the synthetic hybrid [ 3 H]polyriboadenylic acid [poly(rA)]:polydeoxythymidylic acid [poly(dT)] immobilized on the solid matrix of nitrocellulose filters. The hybridization on filter of [ 3 H]poly(rA) to poly(dT) has been explored in terms of efficacy of the process and the response of the product to RNase H. A pulse of uv irradiation of poly(dT) while in dry state on the filter increased its firm binding to the filter in a concentration-dependent manner, resulting in a concomitant increase of the yield of hybrid formation. The filter-immobilized hybrid was 95% resistant to RNase A but sensitive to RNase H. When stored in toluene in the cold the hybrid maintained its stability for over 6 months, as judged by its resistance to RNase A. The method offers a number of advantages over assays that use solution hybrids as substrates and was readily applicable in the screening of leukemic patients, in the leukocytes of which it has demonstrated increased RNase H levels

  16. Oxygen Concentration Inside a Functioning Photosynthetic Cell

    OpenAIRE

    Kihara, Shigeharu; Hartzler, Daniel A.; Savikhin, Sergei

    2014-01-01

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic...

  17. Design and fabrication of optical chemical sensor for detection of nitroaromatic explosives based on fluorescence quenching of phenol red immobilized poly(vinyl alcohol) membrane.

    Science.gov (United States)

    Zarei, Ali Reza; Ghazanchayi, Behnam

    2016-04-01

    The present study developed a new optical chemical sensor for detection of nitroaromatic explosives in liquid phase. The method is based on the fluorescence quenching of phenol red as fluorophore in a poly(vinyl alcohol) (PVA) membrane in the presence of nitroaromatic explosives as quenchers, e.g., 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), 4-nitrotoluene (4-NT), 2,4,6-trinitrobenzene (TNB), and nitrobenzene (NB). For chemical immobilization of phenol red in PVA, phenol red reacted with formaldehyde to produce hydroxymethyl groups and then attached to PVA membrane through the hydroxymethyl groups. The optical sensor showed strong quenching of nitroaromatic explosives. A Stern-Volmer graph for each explosive was constructed and showed that the range of concentration from 5.0 × 10(-6) to 2.5 × 10(-4) mol L(-1) was linear for each explosive and sensitivity varied as TNB >TNT>2,4-DNT>NB>4-NT. The response time of the sensor was within 1 min. The proposed sensor showed good reversibility and reproducibility. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Photoelectrochemical cells based on photosynthetic systems: a review

    Directory of Open Access Journals (Sweden)

    Roman A. Voloshin

    2015-06-01

    Full Text Available Photosynthesis is a process which converts light energy into energy contained in the chemical bonds of organic compounds by photosynthetic pigments such as chlorophyll (Chl a, b, c, d, f or bacteriochlorophyll. It occurs in phototrophic organisms, which include higher plants and many types of photosynthetic bacteria, including cyanobacteria. In the case of the oxygenic photosynthesis, water is a donor of both electrons and protons, and solar radiation serves as inexhaustible source of energy. Efficiency of energy conversion in the primary processes of photosynthesis is close to 100%. Therefore, for many years photosynthesis has attracted the attention of researchers and designers looking for alternative energy systems as one of the most efficient and eco-friendly pathways of energy conversion. The latest advances in the design of optimal solar cells include the creation of converters based on thylakoid membranes, photosystems, and whole cells of cyanobacteria immobilized on nanostructured electrode (gold nanoparticles, carbon nanotubes, nanoparticles of ZnO and TiO2. The mode of solar energy conversion in photosynthesis has a great potential as a source of renewable energy while it is sustainable and environmentally safety as well. Application of pigments such as Chl f and Chl d (unlike Chl a and Chl b, by absorbing the far red and near infrared region of the spectrum (in the range 700-750 nm, will allow to increase the efficiency of such light transforming systems. This review article presents the last achievements in the field of energy photoconverters based on photosynthetic systems.

  19. Elucidation of the outer membrane proteome of Salmonella enterica serovar Typhimurium utilising a lipid-based protein immobilization technique

    Directory of Open Access Journals (Sweden)

    Appleton Hazel

    2010-02-01

    Full Text Available Abstract Background Salmonella enterica serovar Typhimurium (S. Typhimurium is a major cause of human gastroenteritis worldwide. The outer membrane proteins expressed by S. Typhimurium mediate the process of adhesion and internalisation within the intestinal epithelium of the host thus influencing the progression of disease. Since the outer membrane proteins are surface-exposed, they provide attractive targets for the development of improved antimicrobial agents and vaccines. Various techniques have been developed for their characterisation, but issues such as carryover of cytosolic proteins still remain a problem. In this study we attempted to characterise the surface proteome of S. Typhimurium using Lipid-based Protein Immobilisation technology in the form of LPI™ FlowCells. No detergents are required and no sample clean up is needed prior to downstream analysis. The immobilised proteins can be digested with proteases in multiple steps to increase sequence coverage, and the peptides eluted can be characterised directly by liquid chromatography - tandem mass spectrometry (LC-MS/MS and identified from mass spectral database searches. Results In this study, 54 outer membrane proteins, were identified with two or more peptide hits using a multi-step digest approach. Out of these 28 were lipoproteins, nine were involved in transport and three with enzyme activity These included the transporters BtuB which is responsible for the uptake of vitamin B12, LamB which is involved in the uptake of maltose and maltodextrins and LolB which is involved in the incorporation of lipoproteins in the outer membrane. Other proteins identified included the enzymes MltC which may play a role in cell elongation and division and NlpD which is involved in catabolic processes in cell wall formation as well as proteins involved in virulence such as Lpp1, Lpp2 and OmpX. Conclusion Using a multi-step digest approach the LPI™ technique enables the incorporation of a

  20. Development of photosynthetic biofilms affected by dissolved and sorbed copper in a eutrophic river

    NARCIS (Netherlands)

    Barranguet, C.; Plans, M.; Van der Grinten, E.; Sinke, J.J.; Admiraal, W.

    2002-01-01

    Photosynthetic biofilms are capable of immobilizing important concentrations of metals, therefore reducing bioavailability to organisms. But also metal pollution is believed to produce changes in the microalgal species composition of biofilms. We investigated the changes undergone by natural

  1. Fast gradient HPLC method to determine compounds binding to human serum albumin. Relationships with octanol/water and immobilized artificial membrane lipophilicity.

    Science.gov (United States)

    Valko, Klara; Nunhuck, Shenaz; Bevan, Chris; Abraham, Michael H; Reynolds, Derek P

    2003-11-01

    A fast gradient HPLC method (cycle time 15 min) has been developed to determine Human Serum Albumin (HSA) binding of discovery compounds using chemically bonded protein stationary phases. The HSA binding values were derived from the gradient retention times that were converted to the logarithm of the equilibrium constants (logK HSA) using data from a calibration set of molecules. The method has been validated using literature plasma protein binding data of 68 known drug molecules. The method is fully automated, and has been used for lead optimization in more than 20 company projects. The HSA binding data obtained for more than 4000 compounds were suitable to set up global and project specific quantitative structure binding relationships that helped compound design in early drug discovery. The obtained HSA binding of known drug molecules were compared to the Immobilized Artificial Membrane binding data (CHI IAM) obtained by our previously described HPLC-based method. The solvation equation approach has been used to characterize the normal binding ability of HSA, and this relationship shows that compound lipophilicity is a significant factor. It was found that the selectivity of the "baseline" lipophilicity governing HSA binding, membrane interaction, and octanol/water partition are very similar. However, the effect of the presence of positive or negative charges have very different effects. It was found that negatively charged compounds bind more strongly to HSA than it would be expected from the lipophilicity of the ionized species at pH 7.4. Several compounds showed stronger HSA binding than can be expected from their lipophilicity alone, and comparison between predicted and experimental binding affinity allows the identification of compounds that have good complementarities with any of the known binding sites. Copyright 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2236-2248, 2003

  2. A simple fabrication of plasmonic surface-enhanced Raman scattering (SERS) substrate for pesticide analysis via the immobilization of gold nanoparticles on UF membrane

    Science.gov (United States)

    Hong, Jangho; Kawashima, Ayato; Hamada, Noriaki

    2017-06-01

    In this study, we developed a facile fabrication method to access a highly reproducible plasmonic surface enhanced Raman scattering substrate via the immobilization of gold nanoparticles on an Ultrafiltration (UF) membrane using a suction technique. This was combined with a simple and rapid analyte concentration and detection method utilizing portable Raman spectroscopy. The minimum detectable concentrations for aqueous thiabendazole standard solution and thiabendazole in orange extract are 0.01 μg/mL and 0.125 μg/g, respectively. The partial least squares (PLS) regression plot shows a good linear relationship between 0.001 and 100 μg/mL of analyte, with a root mean square error of prediction (RMSEP) of 0.294 and a correlation coefficient (R2) of 0.976 for the thiabendazole standard solution. Meanwhile, the PLS plot also shows a good linear relationship between 0.0 and 2.5 μg/g of analyte, with an RMSEP value of 0.298 and an R2 value of 0.993 for the orange peel extract. In addition to the detection of other types of pesticides in agricultural products, this highly uniform plasmonic substrate has great potential for application in various environmentally-related areas.

  3. Quantitative structure-retention relationship studies using immobilized artificial membrane chromatography I: amended linear solvation energy relationships with the introduction of a molecular electronic factor.

    Science.gov (United States)

    Li, Jie; Sun, Jin; Cui, Shengmiao; He, Zhonggui

    2006-11-03

    Linear solvation energy relationships (LSERs) amended by the introduction of a molecular electronic factor were employed to establish quantitative structure-retention relationships using immobilized artificial membrane (IAM) chromatography, in particular ionizable solutes. The chromatographic indices, log k(IAM), were determined by HPLC on an IAM.PC.DD2 column for 53 structurally diverse compounds, including neutral, acidic and basic compounds. Unlike neutral compounds, the IAM chromatographic retention of ionizable compounds was affected by their molecular charge state. When the mean net charge per molecule (delta) was introduced into the amended LSER as the sixth variable, the LSER regression coefficient was significantly improved for the test set including ionizable solutes. The delta coefficients of acidic and basic compounds were quite different indicating that the molecular electronic factor had a markedly different impact on the retention of acidic and basic compounds on IAM column. Ionization of acidic compounds containing a carboxylic group tended to impair their retention on IAM, while the ionization of basic compounds did not have such a marked effect. In addition, the extra-interaction with the polar head of phospholipids might cause a certain change in the retention of basic compounds. A comparison of calculated and experimental retention indices suggested that the semi-empirical LSER amended by the addition of a molecular electronic factor was able to reproduce adequately the experimental retention factors of the structurally diverse solutes investigated.

  4. Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide

    Directory of Open Access Journals (Sweden)

    Ignazio Renato Bellobono

    2008-01-01

    Full Text Available Photomineralization of methane in air (10.0–1000 ppm (mass/volume of C at 100% relative humidity (dioxygen as oxygen donor was systematically studied at 318±3 K in an annular laboratory-scale reactor by photocatalytic membranes immobilizing titanium dioxide as a function of substrate concentration, absorbed power per unit length of membrane, reactor geometry, and concentration of a proprietary vanadium alkoxide as photopromoter. Kinetics of both substrate disappearance, to yield intermediates, and total organic carbon (TOC disappearance, to yield carbon dioxide, were followed. At a fixed value of irradiance (0.30 W⋅cm-1, the mineralization experiments in gaseous phase were repeated as a function of flow rate (4–400 m3⋅h−1. Moreover, at a standard flow rate of 300 m3⋅h−1, the ratio between the overall reaction volume and the length of the membrane was varied, substantially by varying the volume of reservoir, from and to which circulation of gaseous stream took place. Photomineralization of methane in aqueous solutions was also studied, in the same annular reactor and in the same conditions, but in a concentration range of 0.8–2.0 ppm of C, and by using stoichiometric hydrogen peroxide as an oxygen donor. A kinetic model was employed, from which, by a set of differential equations, four final optimised parameters, k1 and K1, k2 and K2, were calculated, which is able to fit the whole kinetic profile adequately. The influence of irradiance on k1 and k2, as well as of flow rate on K1 and K2, is rationalized. The influence of reactor geometry on k values is discussed in view of standardization procedures of photocatalytic experiments. Modeling of quantum yields, as a function of substrate concentration and irradiance, as well as of concentration of photopromoter, was carried out very satisfactorily. Kinetics of hydroxyl radicals reacting between themselves, leading to hydrogen peroxide, other than with substrate or

  5. The effects of protein crowding in bacterial photosynthetic membranes on the flow of quinone redox species between the photochemical reaction center and the ubiquinol-cytochrome c2 oxidoreductase.

    Science.gov (United States)

    Woronowicz, Kamil; Sha, Daniel; Frese, Raoul N; Sturgis, James N; Nanda, Vikas; Niederman, Robert A

    2011-08-01

    Atomic force microscopy (AFM) of the native architecture of the intracytoplasmic membrane (ICM) of a variety of species of purple photosynthetic bacteria, obtained at submolecular resolution, shows a tightly packed arrangement of light harvesting (LH) and reaction center (RC) complexes. Since there are no unattributed structures or gaps with space sufficient for the cytochrome bc(1) or ATPase complexes, they are localized in membrane domains distinct from the flat regions imaged by AFM. This has generated a renewed interest in possible long-range pathways for lateral diffusion of UQ redox species that functionally link the RC and the bc(1) complexes. Recent proposals to account for UQ flow in the membrane bilayer are reviewed, along with new experimental evidence provided from an analysis of intrinsic near-IR fluorescence emission that has served to test these hypotheses. The results suggest that different mechanism of UQ flow exist between species such as Rhodobacter sphaeroides, with a highly organized arrangement of LH and RC complexes and fast RC electron transfer turnover, and Phaeospirillum molischianum with a more random organization and slower RC turnover. It is concluded that packing density of the peripheral LH2 antenna in the Rba. sphaeroides ICM imposes constraints that significantly slow the diffusion of UQ redox species between the RC and cytochrome bc(1) complex, while in Phs. molischianum, the crowding of the ICM with LH3 has little effect upon UQ diffusion. This supports the proposal that in this type of ICM, a network of RC-LH1 core complexes observed in AFM provides a pathway for long-range quinone diffusion that is unaffected by differences in LH complex composition or organization.

  6. Photosynthetic water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, E.

    1981-01-01

    The photosynthetic unit of hydrogen evolution, the turnover time of photosynthetic hydrogen production, and hydrogenic photosynthesis are discussed in the section on previous work. Recent results are given on simultaneous photoproduction of hydrogen and oxygen, kinetic studies, microscopic marine algae-seaweeds, and oxygen profiles.

  7. Microorganism immobilization

    Science.gov (United States)

    Compere, Alicia L.; Griffith, William L.

    1981-01-01

    Live metabolically active microorganisms are immobilized on a solid support by contacting particles of aggregate material with a water dispersible polyelectrolyte such as gelatin, crosslinking the polyelectrolyte by reacting it with a crosslinking agent such as glutaraldehyde to provide a crosslinked coating on the particles of aggregate material, contacting the coated particles with live microorganisms and incubating the microorganisms in contact with the crosslinked coating to provide a coating of metabolically active microorganisms. The immobilized microorganisms have continued growth and reproduction functions.

  8. Time-resolved imaging and immobilization study of biomaterials on hydrophobic and superhydrophobic surfaces by means of laser-induced forward transfer

    International Nuclear Information System (INIS)

    Boutopoulos, Christos; Chatzipetrou, Marianneza; Zergioti, Ioanna; Papathanasiou, Athanasios G

    2014-01-01

    In this work, we present the generation of high velocity liquid jets of a photosynthetic biomaterial in buffer solution (i.e. thylakoid membranes) and a test solution, using the laser-induced forward transfer (LIFT) technique. The high impact pressure of the collision of the jets on solid substrates, ranging from 0.045 MPa–35 MPa, resulted in strong physical immobilization of the photosynthetic biomaterial on superhydrophobic (SH) poly(methyl methacrylate) (PMMA) surfaces and hydrophobic gold surfaces. The immobilization efficiency was evaluated by fluorescence microscopy, while time-resolved imaging of the LIFT process was carried out to study the corresponding LIFT dynamics. The results show that this simple, direct and chemical-linkers-free immobilization technique is valuable for several biosensors and microfluidic applications since it can be applied to a variety of hydrophobic and SH substrates, leading to the selective immobilization of the biomaterials, due to the high spatial printing resolution of the LIFT technique. (letter)

  9. Biodiesel production with immobilized lipase: A review.

    Science.gov (United States)

    Tan, Tianwei; Lu, Jike; Nie, Kaili; Deng, Li; Wang, Fang

    2010-01-01

    Fatty acid alkyl esters, also called biodiesel, are environmentally friendly and show great potential as an alternative liquid fuel. Biodiesel is produced by transesterification of oils or fats with chemical catalysts or lipase. Immobilized lipase as the biocatalyst draws high attention because that process is "greener". This article reviews the current status of biodiesel production with immobilized lipase, including various lipases, immobilization methods, various feedstocks, lipase inactivation caused by short chain alcohols and large scale industrialization. Adsorption is still the most widely employed method for lipase immobilization. There are two kinds of lipase used most frequently especially for large scale industrialization. One is Candida antartica lipase immobilized on acrylic resin, and the other is Candida sp. 99-125 lipase immobilized on inexpensive textile membranes. However, to further reduce the cost of biodiesel production, new immobilization techniques with higher activity and stability still need to be explored. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Oxygen concentration inside a functioning photosynthetic cell.

    Science.gov (United States)

    Kihara, Shigeharu; Hartzler, Daniel A; Savikhin, Sergei

    2014-05-06

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic photosynthetic bacteria in solitary form could have evolved ∼2.8 billion years ago without special mechanisms to protect them against reactive oxygen species. These mechanisms instead could have been developed during the following ∼500 million years while the oxygen level in the Earth's atmosphere was slowly rising. Excess oxygen concentrations within individual cells of the apomorphic cyanobacteria Synechocystis and Synechococcus are 0.064 and 0.25 μM, respectively. These numbers suggest that intramembrane and intracellular proteins in isolated oxygenic photosynthetic cells are not subjected to excessively high oxygen levels. The situation is different for closely packed colonies of photosynthetic cells. Calculations show that the excess concentration within colonies that are ∼40 μm or larger in diameter can be comparable to the oxygen concentration in air-saturated water, suggesting that species forming colonies require protection against reactive oxygen species even in the absence of oxygen in the surrounding atmosphere. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  11. Synthesis of Pt-immobilized on silica and polystyrene-encapsulated silica and their applications as electrocatalysts in the proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Yi, Sung-Chul; Kim, Chang Young; Jung, Chi Young; Jeong, Sung Hoon; Kim, Wha Jung

    2011-01-01

    Nano sized Pt particles were successfully immobilized onto SiO 2 and polystyrene-encapsulated silica core shell (SiO 2 @PS). To make the immobilization of Pt onto both silica and polystyrene-encapsulated silica core shell, SiO 2 was first functionalized with -NH 2 using 3-amino propyl trimethoxysilane (APTMS) while for core shell, the negatively charged surface of polystyrene (PS) was changed with positive charge by cationic surfactant such as cetyltrimethylammonium chloride (CTACl) to make the formation of SiO 2 shell on preformed PS sphere. Transmission electron micrograph (TEM) images shows that Pt nanoparticles immobilized onto SiO 2 and SiO 2 @PS were to be 3-4 nm without agglomeraiton. The energy dispersive spectroscope (EDS) shows that Pt contents on both SiO 2 and SiO 2 @PS were to be 21.45% and 20.28%, respectively. In case of Pt-SiO 2 @PS, it is believed that Pt should have been immobilized onto PS surface and pore within SiO 2 shell as well as SiO 2 surface. The MEA fabricated with Pt-SiO 2 @PS shows better cell performance than of Pt-SiO 2 .

  12. Nepem-211 ion exchange conductive membrane immobilized tris(2,2´-bipyridyl) ruthenium(II) electrogenerated chemiluminescence flow sensor for high-performance liquid chromatography and its application.

    Science.gov (United States)

    Li, Yongbo; Zhang, Zhujun

    2013-01-01

    We developed a sensitive and robust electrogenerated chemiluminescence (ECL) flow sensor based on Ru(bpy)3(2+) immobilized with a Nepem-211 perfluorinated ion exchange conductance membrane, which has robustness and stability under a wide range of chemical and physical conditions, good electrical conductivity, isotropy and a high exchange capacity for immobilization of Ru(bpy)3(2+). The flow sensor has been used as a post-column detector in high-performance liquid chromatography for determination of erythromycin and clarithromycin in honey and pork, and tricyclic antidepressant drugs in human urine. Under optimal conditions, the linear ranges were 0.03-26 ng/μL and 0.01-1 ng/μL for macrolides and tricyclic antidepressant drugs, respectively. The detection limits were 0.02, 0.01, 0.01, 0.06 and 0.003 ng/μL for erythromycin, clarithromycin, doxepin, amitriptyline and clomipramine, respectively. There is no post-column reagent addition. In addition to the conservation expensive reagents, the experimental setup was simplified. The flow sensor was used for 2 years with high sensitivity and stability. Copyright © 2013 John Wiley & Sons, Ltd.

  13. Nitrogen control of photosynthetic protein synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1986-09-01

    Plant growth is severely affected by impaired photosynthesis resulting from nitrogen deficiency. The molecular aspects of this effect are being studied in the green alga Chlamydomonas grown in continuous culture systems. Photosynthetic membranes of nitrogen-limited cells are dramatically depleted in chlorophylls, xanthophylls and proteins of the light-harvesting complexes. In contrast, enzymes of the reductive pentose phosphate cycle and electron transport chain complexes are reduced only 40 to 65% on a per cell basis comparison with nitrogen-sufficient cultures. From analyses of mRNA levels by in vitro translation and hybridization analyses with cloned DNA sequences for photosynthetic proteins, we have found there are rather minor effects of nitrogen deficiency on nuclear or chloroplast gene transcription. Maturation of a transcript of the nuclear-encoded small subunit of ribulose 1,5-bisphosphate carboxylase is inhibited in nitrogen-deficient cells and causes accumulation of large amounts of mRNA precursors. Most of the effects of nitrogen deficiency on photosynthetic proteins appear to result from posttranscriptional regulatory processes: light-harvesting protein synthesis may be sustained but their import into chloroplasts or translocation to photosynthetic membranes is impaired. Nitrogen-deficient cells lack violaxanthin, a pigment that is essential for the structure, function and biogenesis of the major antenna complexes. The absence of this pigment may be a causative factor for the deficiency of light harvesting complexes. Finally, the accumulation of massive amounts of starch and triglycerides in nitrogen-limited cells indicate there are some genes whose maximal expression is dependent upon nitrogen-limiting conditions. 10 refs.

  14. Photosynthetic Pigments in Diatoms

    OpenAIRE

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-01-01

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvestin...

  15. Evolving a photosynthetic organelle

    Directory of Open Access Journals (Sweden)

    Nakayama Takuro

    2012-04-01

    Full Text Available Abstract The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles. The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  16. Evolving a photosynthetic organelle.

    Science.gov (United States)

    Nakayama, Takuro; Archibald, John M

    2012-04-24

    The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles.The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis--the conversion of solar energy into chemical energy--and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  17. Development of a ratiometric fluorescent urea biosensor based on the urease immobilized onto the oxazine 170 perchlorate-ethyl cellulose membrane.

    Science.gov (United States)

    Dinh Duong, Hong; Il Rhee, Jong

    2015-03-01

    In this work, the oxazine 170 perchlorate (O17)-ethyl cellulose (EC) membrane was successfully applied in the fabrication of a urea-sensing membrane. The urea-sensing membrane was a double layer consisting of the O17-EC membrane and a layer of the enzyme urease entrapped into EC matrix. The sensing principle of urea was based on the hydrolysis reaction of urea under the catalysis of the urease to produce ammonia in water and also on the binding of ammonia with the dye O17 to create the shift in the emission wavelength from λ(em)=630 nm to λ(em)=565 nm. The data collected from the ratio of the fluorescence intensities at λ(em)=630 nm and λ(em)=565 nm was proportional to urea concentration. The urea-sensing membrane with the ratiometric method was used to measure the concentrations of urea in the range of 0.01-0.1 M with a limit of detection (LOD) of 0.027 mM and 0.1-1.0 M with LOD of 0.224 mM. It showed fast response time, high reversibility and long-term stability in this concentration range. The recovery percentage of urea concentrations of the urea-sensing membrane for two kinds of biological urine solutions (BU1, BU2) was around 85-118%. The measured results were in good agreement with standard urea concentrations in the range of 0.06 M to 1.0 M. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Hydrogen production by co-cultures of Lactobacillus and a photosynthetic bacterium, Rhodobacter sphaeroides RV

    Energy Technology Data Exchange (ETDEWEB)

    Asada, Yasuo; Ishimi, Katsuhiro [Department of General Education, College of Science and Technology, Nihon University, Narashinodai, Chiba 274-8501 (Japan); Tokumoto, Masaru; Aihara, Yasuyuki; Oku, Masayo; Kohno, Hideki [Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Izumi-cho, Chiba 275-8575 (Japan); Wakayama, Tatsuki; Miyake, Jun [Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology, Nakoji, Amagasaki, Hyogo 661-0974 (Japan); Tomiyama, Masamitsu [Genetic Diversity Department, National Institute of Agrobiological Science, Tsukuba, Ibaraki 305-8602 (Japan)

    2006-09-15

    Hydrogen production with glucose by using co-immobilized cultures of a lactic acid bacterium, Lactobacillus delbrueckii NBRC13953, and a photosynthetic bacterium, Rhodobacter sphaeroides RV, in agar gels was studied. Glucose was converted to hydrogen gas in a yield of 7.1mol of hydrogen per mole of glucose at a maximum under illuminated conditions. (author)

  19. Photosynthetic Pigments in Diatoms.

    Science.gov (United States)

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-09-16

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries.

  20. Photosynthetic Pigments in Diatoms

    Directory of Open Access Journals (Sweden)

    Paulina Kuczynska

    2015-09-01

    Full Text Available Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries.

  1. Primary photosynthetic processes: from supercomplex to leaf

    NARCIS (Netherlands)

    Broess, K.

    2009-01-01

    This thesis describes fluorescence spectroscopy experiments on photosynthetic complexes that cover the primary photosynthetic processes, from the absorption of light by photosynthetic pigments to a charge separation (CS) in the reaction center (RC). Fluorescence spectroscopy is a useful tool in

  2. Screening therapeutics according to their uptake across the blood-brain barrier: A high throughput method based on immobilized artificial membrane liquid chromatography-diode-array-detection coupled to electrospray-time-of-flight mass spectrometry.

    Science.gov (United States)

    Russo, Giacomo; Grumetto, Lucia; Szucs, Roman; Barbato, Francesco; Lynen, Frederic

    2018-02-07

    The Blood-Brain Barrier (BBB) plays an essential role in protecting the brain tissues against possible injurious substances. In the present work, 79 neutral, basic, acidic and amphoteric structurally unrelated analytes were considered and their chromatographic retention coefficients on immobilized artificial membrane (IAM) stationary phase were determined employing a mass spectrometry (MS) -compatible buffer based on ammonium acetate. Their BBB passage predictive strength was evaluated and the statistical models based on IAM indexes and in silico physico-chemical descriptors showed solid statistics (r 2 (n-1) = 0.78). The predictive strength of the indexes achieved by the MS-compatible method was comparable to that achieved by employing the more "biomimetic" Dulbecco's phosphate buffered saline, even if some differences in the elution order were observed. The method was transferred to the MS, employing a diode-array-detection coupled to an electrospray ionization source and a time-of-flight analyzer. This setup allowed the simultaneous analysis of up to eight analytes, yielding a remarkable acceleration of the analysis time. Copyright © 2018. Published by Elsevier B.V.

  3. Photosynthetic fuel for heterologous enzymes

    DEFF Research Database (Denmark)

    Mellor, Silas Busck; Vavitsas, Konstantinos; Nielsen, Agnieszka Janina Zygadlo

    2017-01-01

    of reducing power. Recent work on the metabolic engineering of photosynthetic organisms has shown that the electron carriers such as ferredoxin and flavodoxin can be used to couple heterologous enzymes to photosynthetic reducing power. Because these proteins have a plethora of interaction partners and rely...... on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However......, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic...

  4. Enhanced performance of immobilized laccase in electrospun fibrous membranes by carbon nanotubes modification and its application for bisphenol A removal from water

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yunrong, E-mail: daiyr@cugb.edu.cn [School of Water Resources and Environment, School of Scientific Research, China University of Geosciences (Beijing), 100083, Beijing (China); Department of Urban Water Environmental Research, Chinese Research Academy of Environmental Sciences, 100012, Beijing (China); Yao, Jun, E-mail: yaojun@cugb.edu.cn [School of Water Resources and Environment, School of Scientific Research, China University of Geosciences (Beijing), 100083, Beijing (China); Song, Yonghui, E-mail: songyhcraes@gmail.com [Department of Urban Water Environmental Research, Chinese Research Academy of Environmental Sciences, 100012, Beijing (China); Liu, Xiaoling, E-mail: liuxl@craes.org.cn [Department of Urban Water Environmental Research, Chinese Research Academy of Environmental Sciences, 100012, Beijing (China); Wang, Siyu, E-mail: wangsy@craes.org.cn [Department of Urban Water Environmental Research, Chinese Research Academy of Environmental Sciences, 100012, Beijing (China); Yuan, Yu, E-mail: yhzmlyy90311@126.com [Department of Urban Water Environmental Research, Chinese Research Academy of Environmental Sciences, 100012, Beijing (China)

    2016-11-05

    Highlights: • Both MWCNTs and laccase could be successfully encapsulated into electrospun fibers. • MWCNTs-LCEFMs showed higher activity recovery and better stability than LCEFMs. • Specific surface area and tensile strength of MWCNTs-LCEFMs were also improved. • Addition of MWCNTs enhanced adsorption and removal efficiency of LCEFMs for BPA. • MWCNTs-LCEFMs exhibited better endurance to the change of pH and temperature. - Abstract: Multi-walled carbon nanotubes (MWCNTs) were used as modified materials to improve the performance of laccase-carrying electrospun fibrous membranes (LCEFMs). The MWCNTs modified LCEFMs (MWCNTs-LCEFMs) were successfully fabricated via emulsion electrospinning, with active laccase and MWCNTs encapsulated inside the fibers. After modified by an optimal amount (1.5 wt%, vs. polymer) of MWCNTs, the obtained MWCNTs-LCEFMs showed not only higher activity recovery (85.3%, vs. free laccase) than LCEFMs (71.2%), but also better storage and operational stability, which were mainly attributed to the promoted electron transfer in laccase-catalytic reaction. Furthermore, the specific surface area and tensile strength of MWCNTs-LCEFMs have also been enhanced nearly 2 and 3 times than those of LCEFMs, respectively. The MWCNTs-LCEFMs were applied to remove the widespread bisphenol A from water, where their removal efficiency reached above 90%, with the degradation efficiency accounting for over 80%, and their adsorption efficiency increased about 45% than that of LCEFMs. In addition, the endurances of MWCNTs-LCEFMs to environmental factors such as pH and temperature were also improved.

  5. Enhanced performance of immobilized laccase in electrospun fibrous membranes by carbon nanotubes modification and its application for bisphenol A removal from water

    International Nuclear Information System (INIS)

    Dai, Yunrong; Yao, Jun; Song, Yonghui; Liu, Xiaoling; Wang, Siyu; Yuan, Yu

    2016-01-01

    Highlights: • Both MWCNTs and laccase could be successfully encapsulated into electrospun fibers. • MWCNTs-LCEFMs showed higher activity recovery and better stability than LCEFMs. • Specific surface area and tensile strength of MWCNTs-LCEFMs were also improved. • Addition of MWCNTs enhanced adsorption and removal efficiency of LCEFMs for BPA. • MWCNTs-LCEFMs exhibited better endurance to the change of pH and temperature. - Abstract: Multi-walled carbon nanotubes (MWCNTs) were used as modified materials to improve the performance of laccase-carrying electrospun fibrous membranes (LCEFMs). The MWCNTs modified LCEFMs (MWCNTs-LCEFMs) were successfully fabricated via emulsion electrospinning, with active laccase and MWCNTs encapsulated inside the fibers. After modified by an optimal amount (1.5 wt%, vs. polymer) of MWCNTs, the obtained MWCNTs-LCEFMs showed not only higher activity recovery (85.3%, vs. free laccase) than LCEFMs (71.2%), but also better storage and operational stability, which were mainly attributed to the promoted electron transfer in laccase-catalytic reaction. Furthermore, the specific surface area and tensile strength of MWCNTs-LCEFMs have also been enhanced nearly 2 and 3 times than those of LCEFMs, respectively. The MWCNTs-LCEFMs were applied to remove the widespread bisphenol A from water, where their removal efficiency reached above 90%, with the degradation efficiency accounting for over 80%, and their adsorption efficiency increased about 45% than that of LCEFMs. In addition, the endurances of MWCNTs-LCEFMs to environmental factors such as pH and temperature were also improved.

  6. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    International Nuclear Information System (INIS)

    Lonergan, N.E.; Britt, L.D.; Sullivan, C.J.

    2014-01-01

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg 2+ and Ca 2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while

  7. A comparison of UV cross-linking and vacuum baking for nucleic acid immobilization and retention

    International Nuclear Information System (INIS)

    Nierzwicki-Bauer, S.A.; Gebhardt, J.S.; Linkkila, L.; Walsh, K.

    1990-01-01

    The effectiveness of UV cross-linking and in vacuo baking for the immobilization and retention of DNA to various solid supports was investigated. Optimal immobilization treatments for supported and unsupported nitrocellulose and nylon membranes were: UV cross-linking at 254 nm with an exposure of 120 milliJoules/cm 2 , or baking in vacuo for two hours at 80 degrees C. UV-immobilized nitrocellulose-based membranes showed no increase in sensitivity when compared to baked membranes. An increase in sensitivity was observed for UV-immobilized nylon membranes as compared with baked nylon membranes in some instances, although this varied within lots of the membranes tested. Repeated strippings and heterologous reprobings resulted in loss of target DNA from UV-immobilized nylon membranes as compared to baked nylon membranes. Loss of target DNA from UV-immobilized nitrocellulose-based membranes due to repeated strippings and reprobings was even more pronounced. In vacuo baking of supported and unsupported nitrocellulose and nylon membranes was more effective for immobilization, and more importantly, for retention of target DNA through many reprobings of the same blot

  8. Interactions between heavy metals and photosynthetic materials studied by optical techniques.

    Science.gov (United States)

    Ventrella, Andrea; Catucci, Lucia; Piletska, Elena; Piletsky, Sergey; Agostiano, Angela

    2009-11-01

    In this work studies on rapid inhibitory interactions between heavy metals and photosynthetic materials at different organization levels were carried out by optical assay techniques, investigating the possibility of applications in the heavy metal detection field. Spinach chloroplasts, thylakoids and Photosystem II proteins were employed as biotools in combination with colorimetric assays based on dichlorophenol indophenole (DCIP) photoreduction and on fluorescence emission techniques. It was found that copper and mercury demonstrated a strong and rapid photosynthetic activity inhibition, that varied from proteins to membranes, while other metals like nickel, cobalt and manganese produced only slight inhibition effects on all tested photosynthetic materials. By emission measurements, only copper was found to rapidly influence the photosynthetic material signals. These findings give interesting information about the rapid effects of heavy metals on isolated photosynthetic samples, and are in addition to the literature data concerning the effects of growth in heavy metal enriched media.

  9. Specific Interaction between Redox Phospholipid Polymers and Plastoquinone in Photosynthetic Electron Transport Chain.

    Science.gov (United States)

    Tanaka, Kenya; Kaneko, Masahiro; Ishikawa, Masahito; Kato, Souichiro; Ito, Hidehiro; Kamachi, Toshiaki; Kamiya, Kazuhide; Nakanishi, Shuji

    2017-04-19

    Redox phospholipid polymers added in culture media are known to be capable of extracting electrons from living photosynthetic cells across bacterial cell membranes with high cytocompatibility. In the present study, we identify the intracellular redox species that transfers electrons to the polymers. The open-circuit electrochemical potential of an electrolyte containing the redox polymer and extracted thylakoid membranes shift to positive (or negative) under light irradiation, when an electron transport inhibitor specific to plastoquinone is added upstream (or downstream) in the photosynthetic electron transport chain. The same trend is also observed for a medium containing living photosynthetic cells of Synechococcus elongatus PCC7942. These results clearly indicate that the phospholipid redox polymers extract photosynthetic electrons mainly from plastoquinone. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Immobilized enzymes and cells

    Energy Technology Data Exchange (ETDEWEB)

    Bucke, C; Wiseman, A

    1981-04-04

    This article reviews the current state of the art of enzyme and cell immobilization and suggests advances which might be made during the 1980's. Current uses of immobilized enzymes include the use of glucoamylase in the production of glucose syrups from starch and glucose isomerase in the production of high fructose corn syrup. Possibilities for future uses of immobilized enzymes and cells include the utilization of whey and the production of ethanol.

  11. Immobilized waste leaching

    International Nuclear Information System (INIS)

    Suarez, A.A.

    1989-01-01

    The main mechanism by which the immobilized radioactive materials can return to biosphere is the leaching due to the intrusion of water into the repositories. Some mathematical models and experiments utilized to evaluate the leaching rates in different immobilization matrices are described. (author) [pt

  12. Stabilized ultrathin liquid membranes for gas separations

    International Nuclear Information System (INIS)

    Deetz, D.W.

    1987-01-01

    Although immobilized liquid membranes have the desirable properties of high selectivity and permeability, their practical application to gas phase separations is hindered because of the instability of the liquid phase and the relative thickness of current membranes. The problem of liquid instability, which is due to both liquid volatilization and flooding, can be reduced, or eliminated, by immobilizing the liquid phase in pores small enough to significantly reduce the molar free energy of the solution via the Kelvin effect. The obstacle of membrane thickness can be overcome by selectively immobilizing the liquid phase into the skin of a porous asymmetric membranes

  13. Special issue of photosynthetic research

    NARCIS (Netherlands)

    Okamura, M.; Wraight, C.A.; van Grondelle, R.

    2014-01-01

    This Special Issue of Photosynthesis Research honors Louis M. N. Duysens, Roderick K. Clayton, and George Feher, three pioneering researchers whose work on bacterial photosynthesis laid much of the groundwork for our understanding of the role of the reaction center in photosynthetic light energy

  14. Immobilization of antibodies and enzyme-labeled antibodies by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.; Suzuki, M.; Adachi, S.

    1983-01-01

    Immobilization of antibodies and enzyme-labeled antibodies by radiation polymerization at low temperatures was studied. The antibody activity of antibody was not affected by irradiation at an irradiation dose of below 8 MR and low temperatures. Immobilization of peroxidase-labeled anti-rabbit IgG goat IgG, anti-peroxidase, peroxidase, and anti-alpha-fetoprotein was carried out with hydrophilic and hydrophobic monomers. The activity of the immobilized enzyme-labeled antibody membranes varied with the thickness of the membranes and increased with decreasing membrane thickness. The activity of the immobilized antibody particles was varied by particle size. Immobilized anti-alpha-fetoprotein particles and membranes can be used for the assay of alpha-fetoprotein by the antigen-antibody reaction, such as a solid-phase sandwich method with high sensitivity

  15. Photosynthetic characteristics of Lycoris aurea and monthly ...

    African Journals Online (AJOL)

    The leaf photosynthetic characteristics of Lycoris aurea, the monthly dynamics in lycorine and galantamine contents in its bulb and the correlation among the photosynthetic characteristics and the lycorine and galantamine during the annual growth period were studied by using LI-6400 portable photosynthetic measurement ...

  16. A novel potassium channel in photosynthetic cyanobacteria.

    Directory of Open Access Journals (Sweden)

    Manuela Zanetti

    Full Text Available Elucidation of the structure-function relationship of a small number of prokaryotic ion channels characterized so far greatly contributed to our knowledge on basic mechanisms of ion conduction. We identified a new potassium channel (SynK in the genome of the cyanobacterium Synechocystis sp. PCC6803, a photosynthetic model organism. SynK, when expressed in a K(+-uptake-system deficient E. coli strain, was able to recover growth of these organisms. The protein functions as a potassium selective ion channel when expressed in Chinese hamster ovary cells. The location of SynK in cyanobacteria in both thylakoid and plasmamembranes was revealed by immunogold electron microscopy and Western blotting of isolated membrane fractions. SynK seems to be conserved during evolution, giving rise to a TPK (two-pore K(+ channel family member which is shown here to be located in the thylakoid membrane of Arabidopsis. Our work characterizes a novel cyanobacterial potassium channel and indicates the molecular nature of the first higher plant thylakoid cation channel, opening the way to functional studies.

  17. Immobilization of enzyme and antibody by low energy electron beam polymerization

    International Nuclear Information System (INIS)

    Kaetsu, Isao; Kumakura, Minoru

    1987-01-01

    Immobilization of glucoamylase and AFP-antibody was studied using an electron beam of relatively low energy. A thin polymer membrane formed by irradiation of monomer enzyme mixture in a buffer, which had a considerable enzymatic activity. A membrane of almost the same thickness and activity was obtained by repeated irradiation. The effect of irradiation conditions on the immobilization and the variations of irradiation method for immobilization were investigated. The immobilization of antibody was carried out in similar ways as for enzyme, and the product also showed a considerable activity. (author)

  18. Plutonium Disposition by Immobilization

    International Nuclear Information System (INIS)

    Gould, T.; DiSabatino, A.; Mitchell, M.

    2000-01-01

    The ultimate goal of the Department of Energy (DOE) Immobilization Project is to develop, construct, and operate facilities that will immobilize between 17 to 50 tonnes (MT) of U.S. surplus weapons-usable plutonium materials in waste forms that meet the ''spent fuel'' standard and are acceptable for disposal in a geologic repository. Using the ceramic can-in-canister technology selected for immobilization, surplus plutonium materials will be chemically combined into ceramic forms which will be encapsulated within large canisters of high level waste (HLW) glass. Deployment of the immobilization capability should occur by 2008 and be completed within 10 years. In support of this goal, the DOE Office of Fissile Materials Disposition (MD) is conducting development and testing (D and T) activities at four DOE laboratories under the technical leadership of Lawrence Livermore National Laboratory (LLNL). The Savannah River Site has been selected as the site for the planned Plutonium Immobilization Plant (PIP). The D and T effort, now in its third year, will establish the technical bases for the design, construction, and operation of the U. S. capability to immobilize surplus plutonium in a suitable and cost-effective manner. Based on the D and T effort and on the development of a conceptual design of the PIP, automation is expected to play a key role in the design and operation of the Immobilization Plant. Automation and remote handling are needed to achieve required dose reduction and to enhance operational efficiency

  19. Influence of thermal light correlations on photosynthetic structures

    Science.gov (United States)

    de Mendoza, Adriana; Manrique, Pedro; Caycedo-Soler, Felipe; Johnson, Neil F.; Rodríguez, Ferney J.; Quiroga, Luis

    2014-03-01

    The thermal light from the sun is characterized by both classical and quantum mechanical correlations. These correlations have left a fingerprint on the natural harvesting structures developed through five billion years of evolutionary pressure, specially in photosynthetic organisms. In this work, based upon previous extensive studies of spatio-temporal correlations of light fields, we hypothesize that structures involving photosensitive pigments like those present in purple bacteria vesicles emerge as an evolutionary response to the different properties of incident light. By using burstiness and memory as measures that quantify higher moments of the photon arrival statistics, we generate photon-time traces. They are used to simulate absorption on detectors spatially extended over regions comparable to these light fields coherence length. Finally, we provide some insights into the connection between these photo-statistical features with the photosynthetic membrane architecture and the lights' spatial correlation. Facultad de Ciencias Uniandes.

  20. Phytochromes in photosynthetically competent plants

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, L.H.

    1990-07-01

    Plants utilize light as a source of information in photomorphogenesis and of free energy in photosynthesis, two processes that are interrelated in that the former serves to increase the efficiency with which plants can perform the latter. Only one pigment involved in photomorphogenesis has been identified unequivocally, namely phytochrome. The thrust of this proposal is to investigate this pigment and its mode(s) of action in photosynthetically competent plants. Our long term objective is to characterize phytochrome and its functions in photosynthetically competent plants from molecular, biochemical and cellular perspectives. It is anticipated that others will continue to contribute indirectly to these efforts at the physiological level. The ultimate goal will be to develop this information from a comparative perspective in order to learn whether the different phytochromes have significantly different physicochemical properties, whether they fulfill independent functions and if so what these different functions are, and how each of the different phytochromes acts at primary molecular and cellular levels.

  1. Electrolyte control of photosynthetic electron transport in cyanobacteria

    International Nuclear Information System (INIS)

    Papageorgiou, G.C.

    1986-01-01

    Ion-permeable cells (permeaplasts) of the cyanobacterium Anacystis nidulans were prepared enzymatically and were characterized with respect to several structural and functional indices. The permeaplasts contain intact, ion-impermeable thylakoids and are photosynthetically active. The authors discuss how, employing these cells, they investigated the effects of cations, acting either on the outer, or on the inner thylakoid membrane surface, on photoinduced electron exchanges with anionic donors (Cyt c-550, plastocyanin, innersurface), or anionic acceptors (FeCN 3- ; outer surface). Cations accelerate such exchanges by accumulating near the solution-membrane interfaces and screening the negative surface charge of membranes. Electrostatic screening, however, is not the only contributing factor, and other electrolyte-linked influences must be invoked in order to interpret the experimental observations

  2. Light transfer in agar immobilized microalgae cell cultures

    Science.gov (United States)

    Kandilian, Razmig; Jesus, Bruno; Legrand, Jack; Pilon, Laurent; Pruvost, Jérémy

    2017-09-01

    This paper experimentally and theoretically investigates light transfer in agar-immobilized cell cultures. Certain biotechnological applications such as production of metabolites secreted by photosynthetic microorganisms require cells to be immobilized in biopolymers to minimize contamination and to facilitate metabolite recovery. In such applications, light absorption by cells is one of the most important parameters affecting cell growth or metabolite productivity. Modeling light transfer therein can aid design and optimize immobilized-cell reactors. In this study, Parachlorella kessleri cells with areal biomass concentrations ranging from 0.36 to 16.9 g/m2 were immobilized in 2.6 mm thick agar gels. The average absorption and scattering cross-sections as well as the scattering phase function of P. kessleri cells were measured. Then, the absorption and transport scattering coefficients of the agar gel were determined using an inverse method based on the modified two-flux approximation. The forward model was used to predict the normal-hemispherical transmittance and reflectance of the immobilized-cell films accounting for absorption and scattering by both microalgae and the agar gel. Good agreement was found between the measured and predicted normal-hemispherical transmittance and reflectance provided absorption and scattering by agar were taken into account. Moreover, good agreement was found between experimentally measured and predicted mean rate of photon absorption. Finally, optimal areal biomass concentration was determined to achieve complete absorption of the incident radiation.

  3. Sequential assembly of photosynthetic units in Rhodobacter sphaeroides as revealed by fast repetition rate analysis of variable bacteriochlorophyll a fluorescence

    Czech Academy of Sciences Publication Activity Database

    Koblížek, Michal; Shih, J. D.; Breitbart, S. I.; Ratcliffe, E. C.; Kolber, Z. S.; Hunter, C. N.; Niederman, R. A.

    2005-01-01

    Roč. 1706, - (2005), s. 220-231 ISSN 0006-3002 R&D Projects: GA ČR GP206/03/P079; GA MŠk LN00A141 Institutional research plan: CEZ:AV0Z50200510 Keywords : membrane development * light-harvesing complex * photosynthetic membrane Subject RIV: EE - Microbiology, Virology

  4. Membrane Compartmentalization Reducing the Mobility of Lipids and Proteins within a Model Plasma Membrane.

    Science.gov (United States)

    Koldsø, Heidi; Reddy, Tyler; Fowler, Philip W; Duncan, Anna L; Sansom, Mark S P

    2016-09-01

    The cytoskeleton underlying cell membranes may influence the dynamic organization of proteins and lipids within the bilayer by immobilizing certain transmembrane (TM) proteins and forming corrals within the membrane. Here, we present coarse-grained resolution simulations of a biologically realistic membrane model of asymmetrically organized lipids and TM proteins. We determine the effects of a model of cytoskeletal immobilization of selected membrane proteins using long time scale coarse-grained molecular dynamics simulations. By introducing compartments with varying degrees of restraints within the membrane models, we are able to reveal how compartmentalization caused by cytoskeletal immobilization leads to reduced and anomalous diffusional mobility of both proteins and lipids. This in turn results in a reduced rate of protein dimerization within the membrane and of hopping of membrane proteins between compartments. These simulations provide a molecular realization of hierarchical models often invoked to explain single-molecule imaging studies of membrane proteins.

  5. Response of the photosynthetic system to altered protein composition and changes in environmental conditions

    NARCIS (Netherlands)

    Tóth, T.

    2014-01-01

    The photosynthetic thylakoid membrane has a hierarchically ordered structure containing pigment-protein complexes that capture solar radiation and convert it into chemical energy. Its highly dynamic structure is capable to continuously respond to the altered environmental conditions, e.g., light

  6. AN APPROACH FOR SCREENING CHOLINESTERASE INHIBITORS IN DRINKING WATER USING AN IMMOBILIZED ENZYME ASSAY

    Science.gov (United States)

    A simple, inexpensive and sensitive method for detecting organophosphate and carbamate insecticides is reported. Acetylcholinesterase was immobilized to PorexR Lateral-FloTM membrane material and remained active for several months at room temperature. The assay was sensitive ...

  7. Antibody Immobilization on Conductive Polymer Coated Nonwoven Fibers for Biosensors

    Directory of Open Access Journals (Sweden)

    Shannon K. MCGRAW

    2011-12-01

    Full Text Available This work is being performed to develop rapid and novel electrochemical biosensors for foodborne pathogen detection. This research focuses on electrotextile platforms to perform both capture and sensing functions in a single component. The biosensor uses nonwoven fiber membranes coated with conductive polymer and functionalized with antibodies for biological capture. This study examines three methods for antibody immobilization: passive adsorption, glutaraldehyde cross-linking, and EDC/Sulfo-NHS cross-linking. Antibodies are immobilized onto the conductive fiber surfaces for the specific capture of a target pathogen. The immobilization and capture capabilities of each method are analyzed through the use of two different fluorescent reporters: FITC and PicoGreen DNA stain. Fluorescence is measured using a fluorescent plate reader and then imaged using a fluorescent microscope. The effect of a blocking agent on specificity is also evaluated. It is found that glutaraldehyde with blocking is the best immobilization method with PicoGreen being the best fluorescent reporter.

  8. Immobilization of microorganisms. Part 1. Preparation of immobilized Lactobacillus bulgaricus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K H

    1981-01-01

    The immobilization of Lactobacillus bulgaricus on polyacrylamide and on alginate beads was investigated. The most active immobilized cells were obtained by entrapment in Ca alginate beads. These immobilized microbial cells, when introduced into 4.5% lactose solution and whey solution showed maximum relative activity of 28% for lactose and 18% for whey compared to free cells.

  9. Protein Structural Deformation Induced Lifetime Shortening of Photosynthetic Bacteria Light-Harvesting Complex LH2 Excited State

    OpenAIRE

    Chen, Xing-Hai; Zhang, Lei; Weng, Yu-Xiang; Du, Lu-Chao; Ye, Man-Ping; Yang, Guo-Zhen; Fujii, Ritsuko; Rondonuwu, Ferdy S.; Koyama, Yasushi; Wu, Yi-Shi; Zhang, J. P.

    2005-01-01

    Photosynthetic bacterial light-harvesting antenna complex LH2 was immobilized on the surface of TiO2 nanoparticles in the colloidal solution. The LH2/TiO2 assembly was investigated by the time-resolved spectroscopic methods. The excited-state lifetimes for carotenoid-containing and carotenoidless LH2 have been measured, showing a decrease in the excited-state lifetime of B850 when LH2 was immobilized on TiO2. The possibility that the decrease of the LH2 excited-state lifetime being caused by ...

  10. Comparison of the external physical damages between laser-assisted and mechanical immobilized human sperm using scanning electronic microscopy.

    Directory of Open Access Journals (Sweden)

    David Y L Chan

    Full Text Available We aim to visualize the external physical damages and distinct external phenotypic effects between mechanical and laser-assisted immobilized human spermatozoa using scanning electronic microscopy (SEM. Human spermatozoa were immobilized mechanically or with laser assistance for SEM examination and the membrane integrities were checked on both types of immobilized spermatozoa. We found evidence of external damages at SEM level on mechanically kinked sperm, but not on laser-assisted immobilized sperm. Although no external damage was found on laser-assist immobilized sperm, there were two distinct types of morphological changes when spermatozoa were stricken by infra-red laser. Coiled tails were immediately formed when Laser pulse was applied to the sperm end piece area, whereas laser applied to the sperm principal piece area resulted in a sharp bend of sperm tails. Sperm immobilized by laser did not exhibit any morphological change if the laser did not hit within the on-screen central target zone or if the laser hit the sperm mid piece or head. Our modified membrane integrity assay revealed that the external membrane of more than half of the laser-assisted immobilized sperm remained intact. In conclusion, mechanical immobilization produced membrane damages whilst laser-assisted immobilization did not result in any external membrane damages besides morphological changes at SEM level.

  11. Limb immobilization and corticobasal syndrome.

    Science.gov (United States)

    Graff-Radford, Jonathan; Boeve, Bradley F; Drubach, Daniel A; Knopman, David S; Ahlskog, J Eric; Golden, Erin C; Drubach, Dina I; Petersen, Ronald C; Josephs, Keith A

    2012-12-01

    Recently, we evaluated two patients with corticobasal syndrome (CBS) who reported symptom onset after limb immobilization. Our objective was to investigate the association between trauma, immobilization and CBS. The charts of forty-four consecutive CBS patients seen in the Mayo Clinic Alzheimer Disease Research Center were reviewed with attention to trauma and limb immobilization. 10 CBS patients (23%) had immobilization or trauma on the most affected limb preceding the onset or acceleration of symptoms. The median age at onset was 61. Six patients manifested their first symptoms after immobilization from surgery or fracture with one after leg trauma. Four patients had pre-existing symptoms of limb dysfunction but significantly worsened after immobilization or surgery. 23 percent of patients had immobilization or trauma of the affected limb. This might have implications for management of CBS, for avoiding injury, limiting immobilization and increasing movement in the affected limb. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Catalytic performances of chemically immobilized urease under static and dynamic conditions: A comparative study

    OpenAIRE

    Yürekli, Yılmaz; Alsoy Altınkaya, Sacide

    2011-01-01

    Immobilized urease has been used for direct removal of urea from aqueous solution and as biological sensing material in the preparation of urea biosensors. The former application is carried out under dynamic condition using ultrafiltration membrane either in tubular form or in flat sheet, while the latter is used in static condition. In this study, the performance of chemically immobilized urease on poly(acrylonitrile-co-sodium methallyl sulfonate) ultrafiltration membrane was determined unde...

  13. Architectural switches in plant thylakoid membranes.

    Science.gov (United States)

    Kirchhoff, Helmut

    2013-10-01

    Recent progress in elucidating the structure of higher plants photosynthetic membranes provides a wealth of information. It allows generation of architectural models that reveal well-organized and complex arrangements not only on whole membrane level, but also on the supramolecular level. These arrangements are not static but highly responsive to the environment. Knowledge about the interdependency between dynamic structural features of the photosynthetic machinery and the functionality of energy conversion is central to understanding the plasticity of photosynthesis in an ever-changing environment. This review summarizes the architectural switches that are realized in thylakoid membranes of green plants.

  14. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  15. Simple and Effective Procedure for Immobilization of Oxidases onto ...

    African Journals Online (AJOL)

    Received 25 June 2003; revised 7 September 2003; accepted 20 January 2004. ... permselective membrane layer prior to enzyme immobilization gave promising result with .... monitored by using litmus paper (Macherey-Nagel, Dueren, ..... a Plasma concentration for healthy adult ranges from 4 to 15 mg L–1 [ref. 31].

  16. Photosynthetic light reactions at the gold interface

    NARCIS (Netherlands)

    Kamran, Muhammad

    2014-01-01

    In the project described in this thesis we studied a simple bio-electronic device for solar energy conversion by surface-assembly of photosynthetic pigment-protein complexes on a bare gold-electrode. Optical excitation of the photosynthetic pigments gives rise to charge separation in the so-called

  17. Interference of Cd2+ in functioning of the photosynthetic apparatus of higher plants

    Directory of Open Access Journals (Sweden)

    Tadeusz Baszyński

    2014-01-01

    Full Text Available The actual opinions concerning the role of Cd2+ in inhibition of photosynthesis have been reviewed. The light phase of photosynthesis, particularly the site of Cd2+ action in the photosynthetic transport chain has been given the greatest attention. Cd2+-induced inhibition of Photosystem II activity as the result of thylakoid membrane degradation has been discussed. The present studies on Cd2+-inhibited dark reactions occurring in stroma has been analysed. Attention has been drawn to the fact that the results of studies in vitro are not always compatible with the changes found in the photosynthetic apparatus of higher plants growing in a Cd2 containing medium.

  18. IMMOBILIZATION OF MICROALGAE ON THE SURFACE OF NEW CROSS-LINKED POLYETHYLENIMINE-BASED SORBENTS.

    Science.gov (United States)

    Vasilieva, Svetlana; Shibzukhova, Karina; Morozov, Alexey; Solovchenko, Alexei; Bessonov, Ivan; Kopitsyna, Maria; Lukyanov, Alexander; Chekanov, Konstantin; Lobakova, Elena

    2018-04-11

    We report on the use of the polyethylenimine-based (PEI) sorbents for immobilization and harvesting of microalgae (MA) cells. Specific materials assessed were porous solid polymers from highly-branched PEI synthesized by cross-linking with epichlorohydrin (ECH) or diethylene glycol diglycidyl ether (DGDE). We estimated the effect of PEI/cross-linker ratio on the MA attachment and biocompatibility of the sorbents with the MA cells. A decrease in the cross-linker percentage resulted in the enhancement of the immobilization efficiency but impaired the cell viability as was manifested by inhibition of the photosynthetic activity of the MA cells. The rate of Chlorella vulgaris cell attachment to the sorbents with ECH was faster as compared to that of the PEI-DGDE-based polymers. The cells immobilized on the PEI-ECH sorbents showed a more profound decline in their viability (assessed via photosynthetic activity). The sorbents with 60% of DGDE were characterized by high immobilization efficiency. These sorbents supported a prolonged cultivation of the immobilized MA without impairing their viability and metabolic activity. We conclude that the sorbents with a lower percentage of DGDE (<30%) and sorbents with ECH are suitable for harvesting of the MA cells intended for immediate downstream processing, potentially without the cell desorption. To the best of our knowledge, this is the first report on successful application of PEI-based sorbents in microalgal biotechnology. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. 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...

  20. Architectural switch in plant photosynthetic membranes induced by light stress

    Czech Academy of Sciences Publication Activity Database

    Herbstová, Miroslava; Tietz, S.; Kinzel, C.; Turkina, M.V.; Kirchhoff, H.

    2012-01-01

    Roč. 109, č. 49 (2012), s. 20130-20135 ISSN 0027-8424 Institutional support: RVO:60077344 Keywords : confocal microscopy * macromolecular crowding * photosynthesis Subject RIV: ED - Physiology Impact factor: 9.737, year: 2012

  1. Electron Beam-Induced Immobilization of Laccase on Porous Supports for Waste Water Treatment Applications

    Directory of Open Access Journals (Sweden)

    Elham Jahangiri

    2014-08-01

    Full Text Available The versatile oxidase enzyme laccase was immobilized on porous supports such as polymer membranes and cryogels with a view of using such biocatalysts in bioreactors aiming at the degradation of environmental pollutants in wastewater. Besides a large surface area for supporting the biocatalyst, the aforementioned porous systems also offer the possibility for simultaneous filtration applications in wastewater treatment. Herein a “green” water-based, initiator-free, and straightforward route to highly reactive membrane and cryogel-based bioreactors is presented, where laccase was immobilized onto the porous polymer supports using a water-based electron beam-initiated grafting reaction. In a second approach, the laccase redox mediators 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS and syringaldehyde were cross-linked instead of the enzyme via electron irradiation in a frozen aqueous poly(acrylate mixture in a one pot set-up, yielding a mechanical stable macroporous cryogel with interconnected pores ranging from 10 to 50 µm in size. The membranes as well as the cryogels were characterized regarding their morphology, chemical composition, and catalytic activity. The reactivity towards waste- water pollutants was demonstrated by the degradation of the model compound bisphenol A (BPA. Both membrane- and cryogel-immobilized laccase remained highly active after electron beam irradiation. Apparent specific BPA removal rates were higher for cryogel- than for membrane-immobilized and free laccase, whereas membrane-immobilized laccase was more stable with respect to maintenance of enzymatic activity and prevention of enzyme leakage from the carrier than cryogel-immobilized laccase. Cryogel-immobilized redox mediators remained functional in accelerating the laccase-catalyzed BPA degradation, and especially ABTS was found to act more efficiently in immobilized than in freely dissolved state.

  2. Separation, identification and quantification of photosynthetic ...

    African Journals Online (AJOL)

    Thirty one photosynthetic pigments (chlorophylls, carotenoids and degradation products) from the seaweeds, Codium dwarkense, (Chlorophyta), , Laurencia obtusa , (Rhodophyta) and , Lobophora variegata, (Phaeophyta), were separated in a single-step procedure by reversed phase high-performance liquid ...

  3. The adaptive response of lichens to mercury exposure involves changes in the photosynthetic machinery

    International Nuclear Information System (INIS)

    Nicolardi, Valentina; Cai, Giampiero; Parrotta, Luigi; Puglia, Michele; Bianchi, Laura; Bini, Luca; Gaggi, Carlo

    2012-01-01

    Lichens are an excellent model to study the bioaccumulation of heavy metals but limited information is available on the molecular mechanisms occurring during bioaccumulation. We investigated the changes of the lichen proteome during exposure to constant concentrations of mercury. We found that most of changes involves proteins of the photosynthetic pathway, such as the chloroplastic photosystem I reaction center subunit II, the oxygen-evolving protein and the chloroplastic ATP synthase β-subunit. This suggests that photosynthesis is a target of the toxic effects of mercury. These findings are also supported by changes in the content of photosynthetic pigments (chlorophyll a and b, and β-carotene). Alterations to the photosynthetic machinery also reflect on the structure of thylakoid membranes of algal cells. Response of lichens to mercury also involves stress-related proteins (such as Hsp70) but not cytoskeletal proteins. Results suggest that lichens adapt to mercury exposure by changing the metabolic production of energy. - Highlights: ► Lichens exposed to Hg° vapors accumulate this metal irreversibly. ► Hg° interferes with physiological processes of the epiphytic lichen Evernia prunastri. ► Hg° promotes changes in the concentration of photosynthetic pigments. ► Hg° treatment causes changes in the ultrastructure of the photobiont plastids. ► Hg° induces changes in the protein machinery involved in the photosynthesis pathway. - Mercury affects the photosynthetic protein machinery of lichens.

  4. PS2013 Satellite Workshop on Photosynthetic Light-Harvesting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Niederman, Robert A. [Rutgers Univ., New Brunswick, NJ (United States); Blankenship, Robert E. [Washington Univ., St. Louis, MO (United States); Frank, Harry A. [Univ. of Connecticut, Storrs, CT (United States)

    2015-02-07

    These funds were used for partial support of the PS2013 Satellite Workshop on Photosynthetic Light-Harvesting Systems, that was held on 8-11 August, 2013, at Washington University, St. Louis, MO. This conference, held in conjunction with the 16th International Congress on Photosynthesis/St. Louis, continued a long tradition of light-harvesting satellite conferences that have been held prior to the previous six international photosynthesis congresses. In this Workshop, the basis was explored for the current interest in replacing fossil fuels with energy sources derived form direct solar radiation, coupled with light-driven electron transport in natural photosynthetic systems and how they offer a valuable blueprint for conversion of sunlight to useful energy forms. This was accomplished through sessions on the initial light-harvesting events in the biological conversion of solar energy to chemically stored energy forms, and how these natural photosynthetic processes serve as a guide to the development of robust bio-hybrid and artificial systems for solar energy conversion into both electricity or chemical fuels. Organized similar to a Gordon Research Conference, a lively, informal and collegial setting was established, highlighting the exchange of exciting new data and unpublished results from ongoing studies. A significant amount of time was set aside for open discussion and interactive poster sessions, with a special session devoted to oral presentations by talented students and postdoctoral fellows judged to have the best posters. This area of research has seen exceptionally rapid progress in recent years, with the availability of a number of antenna protein structures at atomic resolution, elucidation of the molecular surface architecture of native photosynthetic membranes by atomic force microscopy and the maturing of ultrafast spectroscopic and molecular biological techniques for the investigation and manipulation of photosynthetic systems. The conferees

  5. Immobilization of enzymes by radiation

    International Nuclear Information System (INIS)

    Kaetsu, I.; Kumakura, M.; Yoshida, M.; Asano, M.; Himei, M.; Tamura, M.; Hayashi, K.

    1979-01-01

    Immobilization of various enzymes was performed by radiation-induced polymerization of glass-forming monomers at low temperatures. Alpha-amylase and glucoamylase were effectively immobilized in hydrophilic polymer carrier such as poly(2-hydroxyethyl methacrylate) and also in rather hydrophobic carrier such as poly(tetraethylene-glycol diacrylate). Immobilized human hemoglobin underwent the reversible oxygenation concomitantly with change of oxygen concentration outside of the matrices. (author)

  6. Effects of immobilization on spermiogenesis

    Science.gov (United States)

    Meitner, E. R.

    1980-01-01

    The influence of immobilization stress on spermiogenesis in rats was investigated. After 96 hour immobilization, histological changes began to manifest themselves in the form of practically complete disappearance of cell population of the wall of seminiferous tubule as well as a markedly increased number of cells with pathologic mitoses. Enzymological investigations showed various changes of activity (of acid and alkaline phosphatase and nonspecific esterase) in the 24, 48, and 96 hour immobilization groups.

  7. Construction of hybrid photosynthetic units using peripheral and core antennae from two different species of photosynthetic bacteria: detection of the energy transfer from bacteriochlorophyll a in LH2 to bacteriochlorophyll b in LH1.

    Science.gov (United States)

    Fujii, Ritsuko; Shimonaka, Shozo; Uchida, Naoko; Gardiner, Alastair T; Cogdell, Richard J; Sugisaki, Mitsuru; Hashimoto, Hideki

    2008-01-01

    Typical purple bacterial photosynthetic units consist of supra-molecular arrays of peripheral (LH2) and core (LH1-RC) antenna complexes. Recent atomic force microscopy pictures of photosynthetic units in intact membranes have revealed that the architecture of these units is variable (Scheuring et al. (2005) Biochim Bhiophys Acta 1712:109-127). In this study, we describe methods for the construction of heterologous photosynthetic units in lipid-bilayers from mixtures of purified LH2 (from Rhodopseudomonas acidophila) and LH1-RC (from Rhodopseudomonas viridis) core complexes. The architecture of these reconstituted photosynthetic units can be varied by controlling ratio of added LH2 to core complexes. The arrangement of the complexes was visualized by electron-microscopy in combination with Fourier analysis. The regular trigonal array of the core complexes seen in the native photosynthetic membrane could be regenerated in the reconstituted membranes by temperature cycling. In the presence of added LH2 complexes, this trigonal symmetry was replaced with orthorhombic symmetry. The small lattice lengths for the latter suggest that the constituent unit of the orthorhombic lattice is the LH2. Fluorescence and fluorescence-excitation spectroscopy was applied to the set of the reconstituted membranes prepared with various proportions of LH2 to core complexes. Remarkably, even though the LH2 complexes contain bacteriochlorophyll a, and the core complexes contain bacteriochlorophyll b, it was possible to demonstrate energy transfer from LH2 to the core complexes. These experiments provide a first step along the path toward investigating how changing the architecture of purple bacterial photosynthetic units affects the overall efficiency of light-harvesting.

  8. Feasibility of using DNA-immobilized nanocellulose-based immunoadsorbent for systemic lupus erythematosus plasmapheresis.

    Science.gov (United States)

    Xu, Changgang; Carlsson, Daniel O; Mihranyan, Albert

    2016-07-01

    The goal of this project was to study the feasibility of using a DNA-immobilized nanocellulose-based immunoadsorbent for possible application in medical apheresis such as systemic lupus erythematosus (SLE) treatment. Calf thymus DNA was bound to high surface area nanocellulose membrane at varying concentrations using UV-irradiation. The DNA-immobilized samples were characterized with scanning electron microscopy, atomic force microscopy, and phosphorus elemental analysis. The anti-ds-DNA IgG binding was tested in vitro using ELISA. The produced sample showed high affinity in vitro to bind anti-ds-DNA-antibodies from mice, as much as 80% of added IgG was bound by the membrane. Furthermore, the binding efficiency was quantitatively dependent on the amount of immobilized DNA onto nanocellulose membrane. The described nanocellulose membranes are interesting immunoadsorbents for continued clinical studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Dynamic reorganization of photosynthetic supercomplexes during environmental acclimation

    Directory of Open Access Journals (Sweden)

    Jun eMinagawa

    2013-12-01

    Full Text Available Plants and algae have acquired the ability to acclimate to ever-changing environments in order to survive. During photosynthesis, light energy is converted by several membrane protein supercomplexes into electrochemical energy, which is eventually used to assimilate CO2. The efficiency of photosynthesis is modulated by many environmental factors such as quality and quantity of light, temperature, drought, and CO2 concentration, among others. Accumulating evidence indicates that photosynthetic supercomplexes undergo supramolecular reorganization within a short timeframe during acclimation to an environmental change. This reorganization includes state transitions that balance the excitation of photosystem I and II by shuttling peripheral antenna proteins between the two, thermal energy dissipation that occurs at energy-quenching sites within the light-harvesting antenna generated for negative feedback when excess light is absorbed, and cyclic electron flow that is facilitated between photosystem I and the cytochrome bf complex when cells demand more ATP and/or need to activate energy dissipation. This review will highlight the recent findings regarding these environmental acclimation events in model organisms with particular attention to the unicellular green alga C. reinhardtii and with reference to the vascular plant A. thaliana, which offers a glimpse into the dynamic behavior of photosynthetic machineries in nature.

  10. Biodegradation of chlorobenzene using immobilized crude extracts ...

    African Journals Online (AJOL)

    SERVER

    2007-10-04

    Oct 4, 2007 ... immobilized crude extracts were reused for all other experiments and found that immobilization .... India which are of analytical reagent grade. .... 9. 60. 3. 1. Figure 3. Degradation of chlorobenzene by immobilized crude.

  11. Supramolecular protein immobilization on lipid bilayers

    NARCIS (Netherlands)

    Bosmans, R.P.G.; Hendriksen, W.E.; Verheijden, Mark Lloyd; Eelkema, R.; Jonkheijm, Pascal; van Esch, J.H.; Brunsveld, Luc

    2015-01-01

    Protein immobilization on surfaces, and on lipid bilayers specifically, has great potential in biomolecular and biotechnological research. Of current special interest is the immobilization of proteins using supramolecular noncovalent interactions. This allows for a reversible immobilization and

  12. Sterilization of heparinized cuprophan hemodialysis membranes

    NARCIS (Netherlands)

    ten Hoopen, Hermina W.M.; Hinrichs, W.L.J.; Hinrichs, W.L.J.; Engbers, G.H.M.; Feijen, Jan

    1996-01-01

    The effects of sterilization of dry heparinized Cuprophan hemodialysis membranes by means of ethylene oxide (EtO) exposure, gamma irradiation, or steam on the anticoagulant activity and chemical characteristics of immobilized heparin and the permeability of the membrane were investigated.

  13. Iodine immobilization in apatites

    International Nuclear Information System (INIS)

    Audubert, F.; Lartigue, J.E.

    2000-01-01

    In the context of a scientific program on long-lived radionuclide conditioning, a matrix for iodine 129 immobilization has been studied. A lead vanado-phosphate apatite was prepared from the melt of lead vanado-phosphate Pb 3 (VO 4 ) 1.6 (PO 4 ) 0.4 and lead iodide PbI 2 in stoichiometric proportions by calcination at 700 deg. C during 3 hours. Natural sintering of this apatite is not possible because the product decomposition occurs at 400 deg. C. Reactive sintering is the solution. The principle depends on the coating of lead iodide with lead vanado-phosphate. Lead vanado-phosphate coating is used as iodo-apatite reactant and as dense covering to confine iodine during synthesis. So the best condition to immobilize iodine during iodo-apatite synthesis is a reactive sintering at 700 deg. C under 25 MPa. We obtained an iodo-apatite surrounded with dense lead vanadate. Leaching behaviour of the matrix synthesized by solid-solid reaction is under progress in order to determine chemical durability, basic mechanisms of the iodo-apatite alteration and kinetic rate law. Iodo-apatite dissolution rates were pH and temperature dependent. We obtained a rate of 2.5 10 -3 g.m -2 .d -1 at 90 deg. C in initially de-ionised water. (authors)

  14. Reactive membrane technology: Two case studies

    DEFF Research Database (Denmark)

    Zeuner, Birgitte; Luo, Jianquan; Pinelo, Manuel

    2014-01-01

    investigated the effect of applied pressure, enzyme concentration, pH, and membrane properties on fouling-induced enzyme immobilization. In another study, the production of the human milk oligosaccharide 3’-sialyllactose by an engineered sialidase from Trypanosoma rangeli (Tr6) was significantly improved......Enzymatic processes are generally sustainable processes that use mild conditions and natural substrates. Membrane technology can be employed for enzyme immobilization as well as for recycling free enzymes. Using alcohol dehydrogenase (ADH) as part of a process to recycle CO2 to methanol, we...... in an enzymatic membrane reactor. The entire process can be improved by employing a series of ultra- and nanofiltrations....

  15. The electrical potential as a gauge of photosynthetic performance in plant chloroplasts : a patch-clamp study

    NARCIS (Netherlands)

    Voorthuysen, van T.

    1997-01-01

    The earliest events in the energisation of the photosynthetic membrane upon light capture are the formation of a transmembrane electrical potential (AV) and a transmembrane proton gradient (ΔpH). In this thesis ΔΨis employed for the study of the bioenergetics of chloroplast photosynthesis

  16. Assembly of Photosynthetic Antenna Protein / Pigments Complexes from Algae and Plants for Development of Nanobiodevices

    Science.gov (United States)

    2012-07-10

    bacterial photosynthesis . The structure of the reaction center (RC, the first membrane protein to have its structure determined to high resolution) revealed...1282 (2011) & Photosynthesis Res.. 111,63-69(2012)) Bacterial photosynthetic antenna polypeptide (LH) was synthesized as a water-soluble fusion...binding protein and its effect on the stability of reconstituted light-harvesting core antenna complex” , Photosynthesis Res.. 111,63-69(2012)(Doi

  17. Quantification of silver nanoparticle toxicity to algae in soil via photosynthetic and flow-cytometric analyses

    OpenAIRE

    Nam, Sun-Hwa; Il Kwak, Jin; An, Youn-Joo

    2018-01-01

    Soil algae, which have received attention for their use in a novel bioassay to evaluate soil toxicity, expand the range of terrestrial test species. However, there is no information regarding the toxicity of nanomaterials to soil algae. Thus, we evaluated the effects of silver nanoparticles (0–50 mg AgNPs/kg dry weight soil) on the soil alga Chlamydomonas reinhardtii after six days, and assessed changes in biomass, photosynthetic activity, cellular morphology, membrane permeability, esterase ...

  18. C4 photosynthetic machinery: insights from maize chloroplast proteomics

    Directory of Open Access Journals (Sweden)

    Qi eZhao

    2013-04-01

    Full Text Available C4 plants exhibit much higher CO2 assimilation rates than C3 plants. The specialized differentiation of mesophyll cell (M and bundle sheath cell (BS type chloroplasts is unique to C4 plants and improves photosynthesis efficiency. Maize (Zea mays is an important crop and model with C4 photosynthetic machinery. Current high-throughput quantitative proteomics approaches (e.g., 2DE, iTRAQ, and shotgun proteomics have been employed to investigate maize chloroplast structure and function. These proteomic studies have provided valuable information on C4 chloroplast protein components, photosynthesis, and other metabolic mechanisms underlying chloroplast biogenesis, stromal and membrane differentiation, as well as response to salinity, high/low temperature, and light stress. This review presents an overview of proteomics advances in maize chloroplast biology.

  19. Protein translocons in photosynthetic organelles of Paulinella chromatophora

    Directory of Open Access Journals (Sweden)

    Przemysław Gagat

    2014-12-01

    Full Text Available The rhizarian amoeba Paulinella chromatophora harbors two photosynthetic cyanobacterial endosymbionts (chromatophores, acquired independently of primary plastids of glaucophytes, red algae and green plants. These endosymbionts have lost many essential genes, and transferred substantial number of genes to the host nuclear genome via endosymbiotic gene transfer (EGT, including those involved in photosynthesis. This indicates that, similar to primary plastids, Paulinella endosymbionts must have evolved a transport system to import their EGT-derived proteins. This system involves vesicular trafficking to the outer chromatophore membrane and presumably a simplified Tic-like complex at the inner chromatophore membrane. Since both sequenced Paulinella strains have been shown to undergo differential plastid gene losses, they do not have to possess the same set of Toc and Tic homologs. We searched the genome of Paulinella FK01 strain for potential Toc and Tic homologs, and compared the results with the data obtained for Paulinella CCAC 0185 strain, and 72 cyanobacteria, eight Archaeplastida as well as some other bacteria. Our studies revealed that chromatophore genomes from both Paulinella strains encode the same set of translocons that could potentially create a simplified but fully-functional Tic-like complex at the inner chromatophore membranes. The common maintenance of the same set of translocon proteins in two Paulinella strains suggests a similar import mechanism and/or supports the proposed model of protein import. Moreover, we have discovered a new putative Tic component, Tic62, a redox sensor protein not identified in previous comparative studies of Paulinella translocons.

  20. Assessing attitudes toward spinal immobilization.

    Science.gov (United States)

    Bouland, Andrew J; Jenkins, J Lee; Levy, Matthew J

    2013-10-01

    Prospective studies have improved knowledge of prehospital spinal immobilization. The opinion of Emergency Medical Services (EMS) providers regarding spinal immobilization is unknown, as is their knowledge of recent research advances. To examine the attitudes, knowledge, and comfort of prehospital and Emergency Department (ED) EMS providers regarding spinal immobilization performed under a non-selective protocol. An online survey was conducted from May to July of 2011. Participants were drawn from the Howard County Department of Fire and Rescue Services and the Howard County General Hospital ED. The survey included multiple choice questions and responses on a modified Likert scale. Correlation analysis and descriptive data were used to analyze results. Comfort using the Kendrick Extrication Device was low among ED providers. Experienced providers were more likely to indicate comfort using this device. Respondents often believed that spinal immobilization is appropriate in the management of penetrating trauma to the chest and abdomen. Reported use of padding decreased along with the frequency with which providers practice and encounter immobilized patients. Respondents often indicated that they perform spinal immobilization due solely to mechanism of injury. Providers who feel as if spinal immobilization is often performed unnecessarily were more likely to agree that immobilization causes an unnecessary delay in patient care. The results demonstrate the need for improved EMS education in the use of the Kendrick Extrication Device, backboard padding, and spinal immobilization in the management of penetrating trauma. The attitudes highlighted in this study are relevant to the implementation of a selective spinal immobilization protocol. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Phospholipid-sepiolite biomimetic interfaces for the immobilization of enzymes.

    Science.gov (United States)

    Wicklein, Bernd; Darder, Margarita; Aranda, Pilar; Ruiz-Hitzky, Eduardo

    2011-11-01

    Biomimetic interfaces based on phosphatidylcholine (PC) assembled to the natural silicate sepiolite were prepared for the stable immobilization of the urease and cholesterol oxidase enzymes. This is an important issue in practical advanced applications such as biocatalysis or biosensing. The supported lipid bilayer (BL-PC), prepared from PC adsorption, was used for immobilization of enzymes and the resulting biomimetic systems were compared to several other supported layers including a lipid monolayer (ML-PC), a mixed phosphatidylcholine/octyl-galactoside layer (PC-OGal), a cetyltrimethylammonium monolayer (CTA), and also to the bare sepiolite surface. Interfacial characteristics of these layers were investigated with a focus on layer packing density, hydrophilicity/hydrophobicity, and surface charge, which are being considered as key points for enzyme immobilization and stabilization of their biological activity. Cytoplasmic urease and membrane-bound cholesterol oxidase, which served as model enzymes, were immobilized on the different PC-based hybrid materials to probe their biomimetic character. Enzymatic activity was assessed by cyclic voltammetry and UV-vis spectrophotometry. The resulting enzyme/bio-organoclay hybrids were applied as active phase of a voltammetric urea biosensor and cholesterol bioreactor, respectively. Urease supported on sepiolite/BL-PC proved to maintain its enzymatic activity over several months while immobilized cholesterol oxidase demonstrated high reusability as biocatalyst. The results emphasize the good preservation of bioactivity due to the accommodation of the enzymatic system within the biomimetic lipid interface on sepiolite.

  2. MUCOADHESIVE GEL WITH IMMOBILIZED LYSOZYME: PREPARATION AND PROPERTIES

    Directory of Open Access Journals (Sweden)

    Dekina S. S.

    2015-08-01

    Full Text Available The study of non-covalent immobilized lysozyme, as well as physico-chemical and biochemical properties of obtained mucoadhesive gel was the aim of the research. Lysozyme activity was determined by bacteriolytic method (Micrococcus lysodeikticus cells acetone powder was a substrate. Lysozyme immobilization was conducted by the method of entrapment in gel. Enzyme carrier interaction was studied by viscometric, spectrophotometric and spectrofluorimetric methods. Mucoadhesive gel with immobilized lysozyme, possessing antiinflammatory and antimicrobial activities, was prepared. Due to immobilization, protein-polymer complex with the original enzymatic activity was formed. The product is characterized by high mucoadhesive properties, quantitative retaining of protein and bacteriolytic activity, prolonged release of the enzyme, improved biochemical characteristics (extended pH-activity profile, stability in acidic medium and during storage for 2 years, and it is perspective for further studies. The proposed method for lysozyme immobilization in the carboxymethyl cellulose sodium salt gel allows to obtain a stable, highly efficient product, with high adhesive properties for attachment to the mucous membranes, that is promising for use in biomedicine.

  3. HLW immobilization in glass

    International Nuclear Information System (INIS)

    Leroy, P.; Jacquet-Francillon, N.; Runge, S.

    1992-01-01

    The immobilization of High Level Waste in glass in France is a long history which started as early as in the 1950's. More than 30 years of Research and Development have been invested in that field. Two industrial facilities are operating (AVM and R7) and a third one (T7), under cold testing, is planned to start active operation in the mid-92. While vitrification has been demonstrated to be an industrially mastered process, the question of the quality of the final waste product, i.e. the HLW glass, must be addressed. The scope of the present paper is to focus on the latter point from both standpoints of the R and D and of the industrial reality

  4. A rice plastidial nucleotide sugar epimerase is involved in galactolipid biosynthesis and improves photosynthetic efficiency.

    Directory of Open Access Journals (Sweden)

    Chunlai Li

    2011-07-01

    Full Text Available Photosynthesis is the final determinator for crop yield. To gain insight into genes controlling photosynthetic capacity, we selected from our large T-DNA mutant population a rice stunted growth mutant with decreased carbon assimilate and yield production named photoassimilate defective1 (phd1. Molecular and biochemical analyses revealed that PHD1 encodes a novel chloroplast-localized UDP-glucose epimerase (UGE, which is conserved in the plant kingdom. The chloroplast localization of PHD1 was confirmed by immunoblots, immunocytochemistry, and UGE activity in isolated chloroplasts, which was approximately 50% lower in the phd1-1 mutant than in the wild type. In addition, the amounts of UDP-glucose and UDP-galactose substrates in chloroplasts were significantly higher and lower, respectively, indicating that PHD1 was responsible for a major part of UGE activity in plastids. The relative amount of monogalactosyldiacylglycerol (MGDG, a major chloroplast membrane galactolipid, was decreased in the mutant, while the digalactosyldiacylglycerol (DGDG amount was not significantly altered, suggesting that PHD1 participates mainly in UDP-galactose supply for MGDG biosynthesis in chloroplasts. The phd1 mutant showed decreased chlorophyll content, photosynthetic activity, and altered chloroplast ultrastructure, suggesting that a correct amount of galactoglycerolipids and the ratio of glycolipids versus phospholipids are necessary for proper chloroplast function. Downregulated expression of starch biosynthesis genes and upregulated expression of sucrose cleavage genes might be a result of reduced photosynthetic activity and account for the decreased starch and sucrose levels seen in phd1 leaves. PHD1 overexpression increased photosynthetic efficiency, biomass, and grain production, suggesting that PHD1 plays an important role in supplying sufficient galactolipids to thylakoid membranes for proper chloroplast biogenesis and photosynthetic activity. These

  5. [Oligonucleotide derivatives in the nucleic acid hybridization analysis. I. Covalent immobilization of oligonucleotide probes onto the nylon].

    Science.gov (United States)

    Dmitrienko, E V; Pyshnaia, I A; Pyshnyĭ, D V

    2010-01-01

    The features of UV-induced immobilization of oligonucleotides on a nylon membranes and the effectiveness of enzymatic labeling of immobilized probes at heterophase detection of nucleic acids are studied. Short terminal oligothymidilate (up to 10 nt) sequences are suggested to attach to the probe via a flexible ethylene glycol based linker. The presence of such fragment enhances the intensity of immobilization and reduces UV-dependent degradation of the targeted (sequence-specific) part of the probe by reducing the dose needed for the immobilization of DNA. The optimum dose of UV-irradiation is determined to be ~0.4 J/cm(2) at the wavelength 254 nm. This dose provides high level of hybridization signal for immobilized probes with various nucleotide composition of the sequence specific moiety. The amide groups of the polyamide are shown to play the key role in the photoinduced immobilization of nucleic acids, whereas the primary amino groups in the structure of PA is not the center responsible for the covalent binding of DNA by UV-irradiation, as previously believed. Various additives in the soaking solution during the membrane of UV-dependent immobilization of probes are shown to influence its effectiveness. The use of alternative to UV-irradiation system of radical generation are shown to provide the immobilization of oligonucleotides onto the nylon membrane.

  6. Optimization of Phospholipase A1 Immobilization on Plasma Surface Modified Chitosan Nanofibrous Mat

    Directory of Open Access Journals (Sweden)

    Zahra Beig Mohammadi

    2016-01-01

    Full Text Available Phospholipase A1 is known as an effective catalyst for hydrolysis of various phospholipids in enzymatic vegetable oil degumming. Immobilization is one of the most efficient strategies to improve its activity, recovery and functional properties. In this study, chitosan-co-polyethylene oxide (90:10 nanofibrous mat was successfully fabricated and modified with atmospheric plasma at different times (2, 6 and 10 min to interact with enzyme molecules. Scanning electron microscopy images revealed that the membranes retained uniform nanofibrous and open porous structures before and after the treatment. PLA1 was successfully immobilized onto the membrane surfaces via covalent bonds with the functional groups of chitosan nanofibrous mat. Response surface methodology was used to optimize the immobilization conditions for reaching the maximum immobilization efficiency. Enzyme concentration, pH, and immobilization time were found to be significant key factors. Under optimum conditions (5.03 h, pH 5.63, and enzyme dosage 654.36 UI, the atmospheric plasma surface modified chitosan nanofibers reached the highest immobilization efficiency (78.50%. Fourier transform infrared spectroscopy of the control and plasma surface-modified chitosan nanofibers revealed the functional groups of nanofibers and their reaction with the enzyme. The results indicated that surface modification by atmospheric plasma induced an increase in PLA1 loading on the membrane surfaces.

  7. Bacterial Membrane Depolarization-Linked Fuel Cell Potential Burst as Signal for Selective Detection of Alcohol.

    Science.gov (United States)

    Kaushik, Sharbani; Goswami, Pranab

    2018-06-06

    The biosensing application of microbial fuel cell (MFC) is hampered by its long response time, poor selectivity, and technical difficulty in developing portable devices. Herein, a novel signal form for rapid detection of ethanol was generated in a photosynthetic MFC (PMFC). First, a dual chambered (100 mL each) PMFC was fabricated by using cyanobacteria-based anode and abiotic cathode, and its performance was examined for detection of alcohols. A graphene-based nanobiocomposite matrix was layered over graphite anode to support cyanobacterial biofilm growth and to facilitate electron transfer. Injection of alcohols into the anodic chamber caused a transient potential burst of the PMFC within 60 s (load 1000 Ω), and the magnitude of potential could be correlated to the ethanol concentrations in the range 0.001-20% with a limit of detection (LOD) of 0.13% ( R 2 = 0.96). The device exhibited higher selectivity toward ethanol than methanol as discerned from the corresponding cell-alcohol interaction constant ( K i ) of 780 and 1250 mM. The concept was then translated to a paper-based PMFC (p-PMFC) (size ∼20 cm 2 ) wherein, the cells were merely immobilized over the anode. The device with a shelf life of ∼3 months detected ethanol within 10 s with a dynamic range of 0.005-10% and LOD of 0.02% ( R 2 = 0.99). The fast response time was attributed to the higher wettability of ethanol on the immobilized cell surface as validated by the contact angle data. Alcohols degraded the cell membrane on the order of ethanol > methanol, enhanced the redox current of the membrane-bound electron carrier proteins, and pushed the anodic band gap toward more negative value. The consequence was the potential burst, the magnitude of which was correlated to the ethanol concentrations. This novel approach has a great application potential for selective, sensitive, rapid, and portable detection of ethanol.

  8. Ultrafast fluorescence of photosynthetic crystals and light-harvesting complexes

    NARCIS (Netherlands)

    Oort, van B.F.

    2008-01-01

    This thesis focuses on the study of photosynthetic pigment protein complexes using time resolved fluorescence techniques. Fluorescence spectroscopy often requires attaching fluorescent labels to the proteins under investigation. With photosynthetic proteins this is not necessary, because these

  9. High-level-waste immobilization

    International Nuclear Information System (INIS)

    Crandall, J.L.

    1982-01-01

    Analysis of risks, environmental effects, process feasibility, and costs for disposal of immobilized high-level wastes in geologic repositories indicates that the disposal system safety has a low sensitivity to the choice of the waste disposal form

  10. Difference in photosynthetic performance among three peach ...

    African Journals Online (AJOL)

    The effects of low photosynthetic photon flux density (PPFD) on greenhouse grown peach trees ('Qingfeng': Prunus persica L. Batsch, 'NJN76': Prunus persica L. Batsch and 'Maixiang': P. persica var. nectarine) were investigated. Difference in photosynthesis rate (Pn) and stoma morphology among cultivars were studied.

  11. Photosynthetic carbon metabolism in freshwater phytoplankton

    International Nuclear Information System (INIS)

    Groeger, A.W.

    1986-01-01

    Photosynthetic carbon metabolism of natural assemblages of freshwater phytoplankton was measured by following the flow of inorganic 14 C into the photosynthetic end products polysaccharide protein, lipid, and soluble metabolites. Data were collected from a wide range of physical, chemical, and trophic conditions in six southern United States reservoirs, with the primary environmental variables of interest being light intensity and nutrient supply. Polysaccharide and protein were consistently the primary products of photosynthetic carbon metabolism, comprising an average of 70% of the total carbon fixation over a wide range of light intensities. Polysaccharide was quantitatively more important at higher light intensities, and protein at lower light intensities, as light intensity varied both with depth within the water column and over diurnal cycles. Polysaccharide synthesis was more variable over the diurnal period than was protein synthesis. Phytoplankton in the downlake epilimnion of Normandy Lake, a central Tennessee reservoir, responded to summer nitrogen (N) deficiency by increasing relative rates of lipid synthesis from 10-15% to 20-25% of the total photosynthetic carbon fixation. Phytoplankton in more nitrogen-sufficient areas of the reservoir maintained lower rates of lipid synthesis throughout the summer. These results document the occurrence in nature of a relationship between N-deficiency and increased lipid synthesis previously observed only in laboratory algal culture studies

  12. Natural strategies for photosynthetic light harvesting

    NARCIS (Netherlands)

    Croce, R.; van Amerongen, H.

    2014-01-01

    Photosynthetic organisms are crucial for life on Earth as they provide food and oxygen and are at the basis of most energy resources. They have a large variety of light-harvesting strategies that allow them to live nearly everywhere where sunlight can penetrate. They have adapted their pigmentation

  13. Excitons in intact cells of photosynthetic bacteria.

    Science.gov (United States)

    Freiberg, Arvi; Pajusalu, Mihkel; Rätsep, Margus

    2013-09-26

    Live cells and regular crystals seem fundamentally incompatible. Still, effects characteristic to ideal crystals, such as coherent sharing of excitation, have been recently used in many studies to explain the behavior of several photosynthetic complexes, especially the inner workings of the light-harvesting apparatus of the oldest known photosynthetic organisms, the purple bacteria. To this date, there has been no concrete evidence that the same effects are instrumental in real living cells, leaving a possibility that this is an artifact of unnatural study conditions, not a real effect relevant to the biological operation of bacteria. Hereby, we demonstrate survival of collective coherent excitations (excitons) in intact cells of photosynthetic purple bacteria. This is done by using excitation anisotropy spectroscopy for tracking the temperature-dependent evolution of exciton bands in light-harvesting systems of increasing structural complexity. The temperature was gradually raised from 4.5 K to ambient temperature, and the complexity of the systems ranged from detergent-isolated complexes to complete bacterial cells. The results provide conclusive evidence that excitons are indeed one of the key elements contributing to the energetic and dynamic properties of photosynthetic organisms.

  14. Electron microscopy of cyanobacterial membrane proteins

    NARCIS (Netherlands)

    Folea, Ioana Mihaela

    2008-01-01

    The main focus of this thesis is photosynthetic protein complexes, and their organization within the membrane of cyanobacteria. In cyanobacteria large proteins catalyze the light reactions of photosynthesis. One of the key proteins is photosystem II. We have found for the first time by electron

  15. Bioinspired Multifunctional Membrane for Aquatic Micropollutants Removal

    DEFF Research Database (Denmark)

    Cao, Xiaotong; Luo, Jianquan; Woodley, John

    2016-01-01

    Micropollutants present in water have many detrimental effects on the ecosystem. Membrane technology plays an important role in the removal of micropollutants, but there remain significant challenges such as concentration polarization, membrane fouling, and variable permeate quality. The work...... reported here uses a multifunctional membrane with rejection, adsorption, and catalysis functions to solve these problems. On the basis of mussel-inspired chemistry and biological membrane properties, a multifunctional membrane was prepared by applying "reverse filtration" of a laccase solution...... and subsequent "dopamine coating" on a nanofiltration (NF) membrane support, which was tested on bisphenol A (BPA) removal. Three NF membranes were chosen for the preparation of the multifunctional membranes on the basis of the membrane properties and enzyme immobilization efficiency. Compared with the pristine...

  16. 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.

  17. 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.

  18. A forced-flow membrane reactor for transfructosylation using ceramic membrane.

    Science.gov (United States)

    Nishizawa, K; Nakajima, M; Nabetani, H

    2000-04-05

    A forced-flow membrane reactor system for transfructosylation was investigated using several ceramic membranes having different pore sizes. beta-Fructofuranosidase from Aspergillus niger ATCC 20611 was immobilized chemically to the inner surface of a ceramic membrane activated by a silane-coupling reagent. Sucrose solution was forced through the ceramic membrane by crossflow filtration while transfructosylation took place. The saccharide composition of the product, which was a mixture of fructooligosaccharides (FOS), was a function of the permeate flux, which was easily controlled by pressure. Using 0.2 micrometer pore size of symmetric ceramic membrane, the volumetric productivity obtained was 3.87 kg m(-3) s(-1), which was 560 times higher than that in a reported batch system, with a short residence time of 11 s. The half-life of the immobilized enzyme in the membrane was estimated to be 35 days by a long-term operation. Copyright 2000 John Wiley & Sons, Inc.

  19. Status of plutonium ceramic immobilization processes and immobilization forms

    Energy Technology Data Exchange (ETDEWEB)

    Ebbinghaus, B.B.; Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (United States); Vance, E.R.; Jostsons, A. [Australian Nuclear Science and Technology Organization, Menai (Australia)] [and others

    1996-05-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  20. Status of plutonium ceramic immobilization processes and immobilization forms

    International Nuclear Information System (INIS)

    Ebbinghaus, B.B.; Van Konynenburg, R.A.; Vance, E.R.; Jostsons, A.

    1996-01-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R ampersand D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi 2 O 7 ), the desired actinide host phase, with lesser amounts of hollandite (BaAl 2 Ti 6 O 16 ) and rutile (TiO 2 ). Alternative actinide host phases are also being considered. These include pyrochlore (Gd 2 Ti 2 O 7 ), zircon (ZrSiO 4 ), and monazite (CePO 4 ), to name a few of the most promising. R ampersand D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO 2 powder, cold press and sinter fabrication methods, and immobilization form formulation issues

  1. Light-Driven Reconfiguration of a Xanthophyll Violaxanthin in the Photosynthetic Pigment-Protein Complex LHCII: A Resonance Raman Study.

    Science.gov (United States)

    Grudzinski, Wojciech; Janik, Ewa; Bednarska, Joanna; Welc, Renata; Zubik, Monika; Sowinski, Karol; Luchowski, Rafal; Gruszecki, Wieslaw I

    2016-05-19

    Resonance Raman analysis of the photosynthetic complex LHCII, immobilized in a polyacrylamide gel, reveals that one of the protein-bound xanthophylls, assigned as violaxanthin, undergoes light-induced molecular reconfiguration. The phototransformation is selectively observed in a trimeric structure of the complex and is associated with a pronounced twisting and a trans-cis molecular configuration change of the polyene chain of the carotenoid. Among several spectral effects accompanying the reconfiguration there are ones indicating a carotenoid triplet state. Possible physiological importance of the light-induced violaxanthin reconfiguration as a mechanism associated with making the pigment available for enzymatic deepoxidation in the xanthophyll cycle is discussed.

  2. Bioinspired Organic PV Cells Using Photosynthetic Pigment Complex for Energy Harvesting Materials

    Science.gov (United States)

    2010-05-10

    the primary reactions of bacterial photosynthesis . The structure of the reaction center (RC, the first membrane protein to have its structure...most stable and well organized. The best results were only obtained with the subset Random immobilization LH2 LH1-RC AFM image of a bacterial ...Green and Technology, Zero-Carbon Energy Kyoto 2009, Springer, p.129-134 (2010). Reviews: 13 1. K. Iida, T. Dewa, *M. Nango, “Assembly of Bacterial

  3. Effect of low-dose 60Co gamma irradiation on the photosynthetic activity of maize seedlings

    International Nuclear Information System (INIS)

    Turcsanyi, G.

    1979-01-01

    Photosynthesis investigations were carried out on maize seedlings treated with 1000 rad of 60 Co gamma irradiation prior to sowing. The aim of the work was to find out, to what degree the individual processes of photosynthesis are affected by small doses of irradiation. The increase in weight, the chlorophyll a, chlorophyll b and carotinoid content as well as the photosynthetic O 2 -evolution and 14 CO 2 -fixation of the seedlings were measured. The results indicate that, in contradiction to the data given in the literature, the occasional increase in weight caused by small-dose irradiation is not in connection with the membrane-bound part of the photosynthetic apparatus, but it is the consequence of the increased activity of the Calvin-cycle enzymes in the stroma of the chloroplasts. (author)

  4. The Arabidopsis thylakoid chloride channel AtCLCe functions in chloride homeostasis and regulation of photosynthetic electron transport

    Directory of Open Access Journals (Sweden)

    Andrei eHerdean

    2016-02-01

    Full Text Available Chloride ions can be translocated across cell membranes through Cl− channels or Cl−/H+ exchangers. The thylakoid-located member of the Cl− channel CLC family in Arabidopsis thaliana (AtCLCe was hypothesized to play a role in photosynthetic regulation based on the initial photosynthetic characterization of clce mutant lines. The reduced nitrate content of Arabidopsis clce mutants suggested a role in regulation of plant nitrate homeostasis. In this study, we aimed to further investigate the role of AtCLCe in the regulation of ion homeostasis and photosynthetic processes in the thylakoid membrane. We report that the size and composition of proton motive force were mildly altered in two independent Arabidopsis clce mutant lines. Most pronounced effects in the clce mutants were observed on the photosynthetic electron transport of dark-adapted plants, based on the altered shape and associated parameters of the polyphasic OJIP kinetics of chlorophyll a fluorescence induction. Other alterations were found in the kinetics of state transition and in the macro-organisation of photosystem II supercomplexes, as indicated by circular dichroism measurements. Pre-treatment with KCl but not with KNO3 restored the wild-type photosynthetic phenotype. Analyses by transmission electron microscopy revealed a bow-like arrangement of the thylakoid network and a large thylakoid-free stromal region in chloroplast sections from the dark-adapted clce plants. Based on these data, we propose that AtCLCe functions in Cl− homeostasis after transition from light to dark, which affects chloroplast ultrastructure and regulation of photosynthetic electron transport.

  5. Immobilization needs and technology programs

    International Nuclear Information System (INIS)

    Gray, L.W.; Kan, T.; Shaw, H.; Armantrout, G.

    1995-01-01

    In the aftermath of the Cold War, the US and Russia agreed to large reductions in nuclear weapons. To aid in the selection of long-term management options, DOE has undertaken a multifaceted study to select options for storage and disposition of plutonium in keeping with US policy that plutonium must be subjected to the highest standards of safety, security, and accountability. One alternative being considered is immobilization. To arrive at a suitable immobilization form, we first reviewed published information on high-level waste immobilization technologies and identified 72 possible plutonium immobilization forms to be prescreened. Surviving forms were further screened using multi-attribute utility analysis to determine the most promising technology families. Promising immobilization families were further evaluated to identify chemical, engineering, environmental, safety, and health problems that remain to be solved prior to making technical decisions as to the viability of using the form for long- term disposition of plutonium. From this evaluation, a detailed research and development plan has been developed to provide answers to these remaining questions

  6. Bio-coloration of bacterial cellulose assisted by immobilized laccase.

    Science.gov (United States)

    Song, Ji Eun; Su, Jing; Noro, Jennifer; Cavaco-Paulo, Artur; Silva, Carla; Kim, Hye Rim

    2018-02-13

    In this work a process for the bio-coloration of bacterial cellulose (BC) membranes was developed. Laccase from Myceliophthora thermophila was immobilized onto BC membranes and retained up to 88% of residual activity after immobilization. Four compounds belonging to the flavonoids family were chosen to test the in situ polymerase activity of immobilized laccase. All the flavonoids were successfully polymerized by laccase giving rise to yellow, orange and dark brown oligomers which conferred color to the BC support. The optimal bio-coloration conditions were studied for two of the tested flavonoids, catechol and catechin, by varying the concentration and time of incubation. High color depth and resistance to washing were obtained for both compounds. The highly porous bacterial cellulose material demonstrated great performance as a bio-coloration support, in contrast to other materials cited in literature, like cotton or wool. The process developed is presented as an environmentally friendly alternative for bacterial cellulose bio-coloration and will contribute deeply for the development of new fashionable products within this material.

  7. [Engineering photosynthetic cyanobacterial chassis: a review].

    Science.gov (United States)

    Wu, Qin; Chen, Lei; Wang, Jiangxin; Zhang, Weiwen

    2013-08-01

    Photosynthetic cyanobacteria possess a series of good properties, such as their abilities to capture solar energy for CO2 fixation, low nutritional requirements for growth, high growth rate, and relatively simple genetic background. Due to the high oil price and increased concern of the global warming in recent years, cyanobacteria have attracted widespread attention because they can serve as an 'autotrophic microbial factory' for producing renewable biofuels and fine chemicals directly from CO2. Particularly, significant progress has been made in applying synthetic biology techniques and strategies to construct and optimize cyanobacteria chassis. In this article, we critically summarized recent advances in developing new methods to optimize cyanobacteria chassis, improving cyanobacteria photosynthetic efficiency, and in constructing cyanobacteria chassis tolerant to products or environmental stresses. In addition, various industrial applications of cyanobacteria chassis are also discussed.

  8. Photosynthetic Rates of Citronella and Lemongrass 1

    Science.gov (United States)

    Herath, H. M. Walter; Ormrod, Douglas P.

    1979-01-01

    Ten selections of citronella (Cymbopogon nardus [L.] Rendle) were grown at 32/27, 27/21, or 15/10 C day/night temperatures, and plants from three populations of lemongrass (Cymbopogon citratus [D.C.] Stapf from Japan or Sri Lanka and Cymbopogon flexuosus [D.C.] Stapf from India) were grown at 8- or 15-hour photoperiods. Net photosynthetic rates of mature leaves were measured in a controlled environment at 25 C and 260 microeinsteins per meter2 per second. Rates declined with increasing leaf age, and from the tip to the base of the leaf blade. Rates for citronella leaves grown at 15/10 C were extremely low for all selections. Highest rates of net photosynthesis were recorded for four selections grown at 27/21 C and for two selections grown at 32/27 C. Lemongrass grown at 8-hour photoperiod had higher photosynthetic rates than that grown at 15-hour photoperiod. PMID:16660737

  9. BOREAS TE-9 NSA Photosynthetic Response Data

    Science.gov (United States)

    Hall, Forrest G.; Curd, Shelaine (Editor); Dang, Qinglai; Margolis, Hank; Coyea, Marie

    2000-01-01

    The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-9 (Terrestrial Ecology) team collected several data sets related to chemical and photosynthetic properties of leaves. This data set describes: (1) the response of leaf and shoot-level photosynthesis to ambient and intercellular CO2 concentration, temperature, and incident photosynthetically active radiation (PAR) for black spruce, jack pine, and aspen during the three intensive field campaigns (IFCs) in 1994 in the Northern Study Area (NSA); (2) the response of stomatal conductance to vapor pressure difference throughout the growing season of 1994; and (3) a range of shoot water potentials (controlled in the laboratory) for black spruce and jack pine. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  10. 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...

  11. Immobilization of cellulase by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1983-01-01

    Immobilization of cellulase by radiation polymerization at low temperatures was studied. The enzymatic activity of immobilized cellulase pellets varied with the monomer, enzyme concentration, and the thickness of immobilized cellulase pellets. The optimum monomer concentration in the immobilization of cellulase was 30-50% at the pellet thickness of 1.0 mm, in which the enzymatic activity was 50%. The enzymatic activity of immobilized cellulase pellets was examined using various substrates such as cellobiose, carboxymethylcellulose, and paper pretreated by radiation. It was found that irradiated paper can be hydrolyzed by immobilized cellulase pellets. (author)

  12. Coral bleaching independent of photosynthetic activity.

    Science.gov (United States)

    Tolleter, Dimitri; Seneca, François O; DeNofrio, Jan C; Krediet, Cory J; Palumbi, Stephen R; Pringle, John R; Grossman, Arthur R

    2013-09-23

    The global decline of reef-building corals is due in part to the loss of algal symbionts, or "bleaching," during the increasingly frequent periods of high seawater temperatures. During bleaching, endosymbiotic dinoflagellate algae (Symbiodinium spp.) either are lost from the animal tissue or lose their photosynthetic pigments, resulting in host mortality if the Symbiodinium populations fail to recover. The >1,000 studies of the causes of heat-induced bleaching have focused overwhelmingly on the consequences of damage to algal photosynthetic processes, and the prevailing model for bleaching invokes a light-dependent generation of toxic reactive oxygen species (ROS) by heat-damaged chloroplasts as the primary trigger. However, the precise mechanisms of bleaching remain unknown, and there is evidence for involvement of multiple cellular processes. In this study, we asked the simple question of whether bleaching can be triggered by heat in the dark, in the absence of photosynthetically derived ROS. We used both the sea anemone model system Aiptasia and several species of reef-building corals to demonstrate that symbiont loss can occur rapidly during heat stress in complete darkness. Furthermore, we observed damage to the photosynthetic apparatus under these conditions in both Aiptasia endosymbionts and cultured Symbiodinium. These results do not directly contradict the view that light-stimulated ROS production is important in bleaching, but they do show that there must be another pathway leading to bleaching. Elucidation of this pathway should help to clarify bleaching mechanisms under the more usual conditions of heat stress in the light. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Ionizing radiation and photosynthetic ability of cyanobacteria

    International Nuclear Information System (INIS)

    Agarwal, Rachna; Sainis, Jayashree K.

    2006-01-01

    Unicellular photoautotrophic cyanobacteria, Anacystis nidulans when exposed to lethal dose of 1.5 kGy of 60 Co γ- radiation (D 10 = 257.32 Gy) were as effective photosynthetical as unirradiated controls immediately after irradiation although level of ROS was higher by several magnitudes in these irradiated cells. The results suggested the preservation of the functional integrity of thylakoids even after exposure to lethal dose of ionizing radiation. (author)

  14. Development of a Photosynthetic Microbial Electrochemical Cell (PMEC Reactor Coupled with Dark Fermentation of Organic Wastes: Medium Term Perspectives

    Directory of Open Access Journals (Sweden)

    Samir Bensaid

    2015-01-01

    Full Text Available In this article the concept, the materials and the exploitation potential of a photosynthetic microbial electrochemical cell for the production of hydrogen driven by solar power are investigated. In a photosynthetic microbial electrochemical cell, which is based on photosynthetic microorganisms confined to an anode and heterotrophic bacteria confined to a cathode, water is split by bacteria hosted in the anode bioactive film. The generated electrons are conveyed through external “bio-appendages” developed by the bacteria to transparent nano-pillars made of indium tin oxide (ITO, Fluorine-doped tin oxide (FTO or other conducting materials, and then transferred to the cathode. On the other hand, the generated protons diffuse to the cathode via a polymer electrolyte membrane, where they are reduced by the electrons by heterotrophic bacteria growing attached to a similar pillared structure as that envisaged for the anode and supplemented with a specific low cost substrate (e.g., organic waste, anaerobic digestion outlet. The generated oxygen is released to the atmosphere or stored, while the produced pure hydrogen leaves the electrode through the porous layers. In addition, the integration of the photosynthetic microbial electrochemical cell system with dark fermentation as acidogenic step of anaerobic digester, which is able to produce additional H2, and the use of microbial fuel cell, feed with the residues of dark fermentation (mainly volatile fatty acids, to produce the necessary extra-bias for the photosynthetic microbial electrochemical cell is here analyzed to reveal the potential benefits to this novel integrated technology.

  15. Immobile Complex Verbs in Germanic

    DEFF Research Database (Denmark)

    Vikner, Sten

    2005-01-01

    the V° requirements or the V* requirements. Haider (1993, p. 62) and Koopman (1995), who also discuss such immobile verbs, only account for verbs with two prefix-like parts (e.g., German uraufführen ‘to perform (a play) for the first time' or Dutch herinvoeren ‘to reintroduce'), not for the more...... frequent type with only one prefix-like part (e.g., German bauchreden/Dutch buikspreken ‘to ventriloquize'). This analysis will try to account not only for the data discussed in Haider (1993) and Koopman (1995) but also for the following: - why immobile verbs include verbs with only one prefix-like part...... are immobile, - why such verbs are not found in Germanic VO-languages such as English and Scandinavian....

  16. The Arabidopsis ppi1 Mutant Is Specifically Defective in the Expression, Chloroplast Import, and Accumulation of Photosynthetic ProteinsW⃞

    Science.gov (United States)

    Kubis, Sybille; Baldwin, Amy; Patel, Ramesh; Razzaq, Azam; Dupree, Paul; Lilley, Kathryn; Kurth, Joachim; Leister, Dario; Jarvis, Paul

    2003-01-01

    The import of nucleus-encoded proteins into chloroplasts is mediated by translocon complexes in the envelope membranes. A component of the translocon in the outer envelope membrane, Toc34, is encoded in Arabidopsis by two homologous genes, atTOC33 and atTOC34. Whereas atTOC34 displays relatively uniform expression throughout development, atTOC33 is strongly upregulated in rapidly growing, photosynthetic tissues. To understand the reason for the existence of these two related genes, we characterized the atTOC33 knockout mutant ppi1. Immunoblotting and proteomics revealed that components of the photosynthetic apparatus are deficient in ppi1 chloroplasts and that nonphotosynthetic chloroplast proteins are unchanged or enriched slightly. Furthermore, DNA array analysis of 3292 transcripts revealed that photosynthetic genes are moderately, but specifically, downregulated in ppi1. Proteome differences in ppi1 could be correlated with protein import rates: ppi1 chloroplasts imported the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit and 33-kD oxygen-evolving complex precursors at significantly reduced rates, but the import of a 50S ribosomal subunit precursor was largely unaffected. The ppi1 import defect occurred at the level of preprotein binding, which is consistent with a role for atToc33 during preprotein recognition. The data suggest that atToc33 is involved preferentially in the import of photosynthetic proteins and, by extension, that atToc34 is involved in the import of nonphotosynthetic chloroplast proteins. PMID:12897258

  17. Immobilization of acid digestion residue

    International Nuclear Information System (INIS)

    Greenhalgh, W.O.; Allen, C.R.

    1983-01-01

    Acid digestion treatment of nuclear waste is similar to incineration processes and results in the bulk of the waste being reduced in volume and weight to some residual solids termed residue. The residue is composed of various dispersible solid materials and typically contains the resultant radioactivity from the waste. This report describes the immobilization of the residue in portland cement, borosilicate glass, and some other waste forms. Diagrams showing the cement and glass virtification parameters are included in the report as well as process steps and candidate waste product forms. Cement immobilization is simplest and probably least expensive; glass vitrification exhibits the best overall volume reduction ratio

  18. Progress in surface and membrane science

    CERN Document Server

    Cadenhead, D A

    1976-01-01

    Progress in Surface and Membrane Science, Volume 10 covers the advances in surface and membrane science. The book discusses the selective changes of cellular particles influencing sedimentation properties; and the rotating disk and ring-disk electrodes in investigations of surface phenomena at the metal-electrolyte interface. The text also describes the membrane potential of phospholipid bilayer and biological membranes; the adsorption of surfactant monolayers at gas/liquid and liquid/liquid interfaces; and the enzymes immobilized on glass. Chemists and people involved in electrochemistry will

  19. Study on improvement of continuous hydrogen production by photosynthetic biofilm in interior illuminant reactor.

    Science.gov (United States)

    Liu, Wenhui; Yuan, Linjiang; Wei, Bo

    2016-09-01

    In the present study, a new type of interior optical fiber illuminating reactor was developed for H2 production to solve the problem of luminous intensity attenuation at the center portion of a reactor, and an immobilization technique was used to enhance the stability of a continuous hydrogen production process with attached photosynthetic bacteria, using glucose as a sole carbon substrate for the indigenous photosynthetic bacteria (PSB) Rhodopseudomonas palustris SP-6. Results of the experiments showed that the interior optical fiber illuminating reactor produces H2 more efficiently and productively than the exterior light source reactor, with the cumulative H2 production, the maximum H2 production rate and H2 yield increased by 813ml, 11.3ml l-1 h-1 and 22.3%, respectively. The stability of the product of continuous hydrogen was realized by immobilizing PSB on the surface of powder active carbon(PAC). After adding the dosage of 2.0g l-1 PAC, the continuous steady operation of H2 production gave a high H2 yield of 1.398 mol H2 mol-1 glucose and an average H2 production rate of 35.1ml l-1 h-1 illuminating with a single interior optical fiber light source. Meanwhile, a higher H2 yield of 1.495 mol H2 mol-1 glucose and an average H2 production rate of 38.7ml l-1 h-1 were attained illuminating with a compound lamp in the continuous H2 production for 20 days.

  20. Radiation immobilization of catalase and its application

    International Nuclear Information System (INIS)

    Wang Guanghui; Ha Hongfei; Wang Xia; Wu Jilan

    1988-01-01

    Catalase was immobilized by a chemical method on porous polyacrylamide particles produced by radiation polymerization of acrylamide monomer at low temperature (-78 0 C). Activity of immobilized catalase was enhanced distinctly by joining a chemical arm to the support. The method of recovery of catalase activity on immobilized polymer was found by soaking it in certain buffer. The treatment of H 2 O 2 both in aqueous solution and alcoholic solution by using the immobilized catalase was performed. (author)

  1. Bio-Inspired Polymer Membrane Surface Cleaning

    Directory of Open Access Journals (Sweden)

    Agnes Schulze

    2017-03-01

    Full Text Available To generate polyethersulfone membranes with a biocatalytically active surface, pancreatin was covalently immobilized. Pancreatin is a mixture of digestive enzymes such as protease, lipase, and amylase. The resulting membranes exhibit self-cleaning properties after “switching on” the respective enzyme by adjusting pH and temperature. Thus, the membrane surface can actively degrade a fouling layer on its surface and regain initial permeability. Fouling tests with solutions of protein, oil, and mixtures of both, were performed, and the membrane’s ability to self-clean the fouled surface was characterized. Membrane characterization was conducted by investigation of the immobilized enzyme concentration, enzyme activity, water permeation flux, fouling tests, porosimetry, X-ray photoelectron spectroscopy, and scanning electron microscopy.

  2. Improvement of enantioselectivity by immobilized imprinting of epoxide hydrolase from Rhodotorula glutinis

    NARCIS (Netherlands)

    Kronenburg, N.A.E.; Bont, de J.A.M.; Fischer, L.

    2001-01-01

    The yeast Rhodotorula glutinis contains an enantioselective, membrane-associated epoxide hydrolase (EH). Partially purified EH was immobilized in a two-step procedure. In the first step, the proteins were derivatized with itaconic anhydride. In the second step, the derivatized proteins were

  3. Immobilization of Mitochondria on Graphene

    Science.gov (United States)

    2013-08-29

    poly-L-lysine has also been reported for immobilization of yeast mitochondria. Coating was performed by repetitive washing of cover slips with 0.02...of Poly-L-lysine Applications of PLL PLL is a production of bacterial fermentation and is used as a food preservative. In biology, PLL is used in

  4. Immobilization of Colloidal Monolayers at Fluid–Fluid Interfaces

    Directory of Open Access Journals (Sweden)

    Peter T. Bähler

    2016-07-01

    Full Text Available Monolayers of colloidal particles trapped at an interface between two immiscible fluids play a pivotal role in many applications and act as essential models in fundamental studies. One of the main advantages of these systems is that non-close packed monolayers with tunable inter-particle spacing can be formed, as required, for instance, in surface patterning and sensing applications. At the same time, the immobilization of particles locked into desired structures to be transferred to solid substrates remains challenging. Here, we describe three different strategies to immobilize monolayers of polystyrene microparticles at water–decane interfaces. The first route is based on the leaking of polystyrene oligomers from the particles themselves, which leads to the formation of a rigid interfacial film. The other two rely on in situ interfacial polymerization routes that embed the particles into a polymer membrane. By tracking the motion of the colloids at the interface, we can follow in real-time the formation of the polymer membranes and we interestingly find that the onset of the polymerization reaction is accompanied by an increase in particle mobility determined by Marangoni flows at the interface. These results pave the way for future developments in the realization of thin tailored composite polymer-particle membranes.

  5. Response of plasma membrane H+-ATPase in rice (Oryza sativa) seedlings to simulated acid rain.

    Science.gov (United States)

    Liang, Chanjuan; Ge, Yuqing; Su, Lei; Bu, Jinjin

    2015-01-01

    Understanding the adaptation of plants to acid rain is important to find feasible approaches to alleviate such damage to plants. We studied effects of acid rain on plasma membrane H(+)-ATPase activity and transcription, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate during stress and recovery periods. Simulated acid rain at pH 5.5 did not affect plasma membrane H(+)-ATPase activity, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate. Plasma membrane H(+)-ATPase activity and transcription in leaves treated with acid rain at pH 3.5 was increased to maintain ion homeostasis by transporting excessive H(+) out of cells. Then intracellular H(+) was close to the control after a 5-day recovery, alleviating damage on membrane and sustaining photosynthetic efficiency and growth. Simulated acid rain at pH 2.5 inhibited plasma membrane H(+)-ATPase activity by decreasing the expression of H(+)-ATPase at transcription level, resulting in membrane damage and abnormal intracellular H(+), and reduction in photosynthetic efficiency and relative growth rate. After a 5-day recovery, all parameters in leaves treated with pH 2.5 acid rain show alleviated damage, implying that the increased plasma membrane H(+)-ATPase activity and its high expression were involved in repairing process in acid rain-stressed plants. Our study suggests that plasma membrane H(+)-ATPase can play a role in adaptation to acid rain for rice seedlings.

  6. Sterilization of heparinized cuprophan hemodialysis membranes

    OpenAIRE

    ten Hoopen, Hermina W.M.; Hinrichs, W.L.J.; Hinrichs, W.L.J.; Engbers, G.H.M.; Feijen, Jan

    1996-01-01

    The effects of sterilization of dry heparinized Cuprophan hemodialysis membranes by means of ethylene oxide (EtO) exposure, gamma irradiation, or steam on the anticoagulant activity and chemical characteristics of immobilized heparin and the permeability of the membrane were investigated. Sterilization did not result in a release of heparin or heparin fragments from heparinized Cuprophan. Sterilization of heparinized Cuprophan by means of EtO exposure and gamma irradiation induced a slight, i...

  7. Manganese in photosynthetic oxygen evolution: An edge and EXAFS study

    International Nuclear Information System (INIS)

    Yachandra, V.K.; Guiles, R.D.; McDermott, A.; Britt, R.D.; Dexheimer, S.L.; Saver, K.; Klein, M.P.

    1985-01-01

    The authors edge studies have previously shown that the Mn edges in photosynthetic samples in the S 1 and S 2 states fall into the range for Mn III and Mn IV complexes, and that the K-edge energy increases appreciably on advancing S 1 to S 2 . This was the first evidence that manganese is directly involved in the storage of oxidizing equivalents. More recently, they have extended this result with better quality data from both spinach and a thermophilic cyanobacterium. The newer results show an interesting structure to the edges, including a 1s to 3d transition. The EXAFS results for spinach membranes show that the salient features of the Mn structure are the same in the S 1 and S 2 states. These features are a Mn neighbor at approx. =2.7 A and O or N neighbors at approx. =1.75 A and approx. =2.0 A. The EXAFS spectrum of the S 1 state of the thermophilic blue green algae are strikingly similar to that of spinach

  8. Biocatalytic Self-Cleaning Polymer Membranes

    Directory of Open Access Journals (Sweden)

    Agnes Schulze

    2015-09-01

    Full Text Available Polymer membrane surfaces have been equipped with the digestive enzyme trypsin. Enzyme immobilization was performed by electron beam irradiation in aqueous media within a one-step method. Using this method, trypsin was covalently and side-unspecific attached to the membrane surface. Thus, the use of preceding polymer functionalization and the use of toxic solvents or reagents can be avoided. The resulting membranes showed significantly improved antifouling properties as demonstrated by repeated filtration of protein solutions. Furthermore, the biocatalytic membrane can be simply “switched on” to actively degrade a fouling layer on the membrane surface and regain the initial permeability. The membrane pore structure (pore size and porosity was neither damaged by the electron beam treatment nor blocked by the enzyme loading, ensuring a stable membrane performance.

  9. Magnetic irone oxide nanoparticles in photosynthetic systems

    International Nuclear Information System (INIS)

    Khalilov, R.I.; Nasibova, A.N.; Khomutov, G.B.

    2014-01-01

    Full text : It was found and studied the effect of biogenic formation of magnetic inclusions in photosynthetic systems - in various higher plants under the influence of some external stress factors (radiation impact, moisture deficit) and in a model system - a suspension of chloroplasts. For registration and characterization of magnetic nanoparticles in the samples used EPR spectrometer because superparamagnetic and ferromagnetic nanoparticles have a chcracteristic signals of electron magnetic resonance. For direct visualization of magnetic nanoparticles it was used the method of transmission electron microscopy

  10. Engineering cyanobacteria as photosynthetic feedstock factories.

    Science.gov (United States)

    Hays, Stephanie G; Ducat, Daniel C

    2015-03-01

    Carbohydrate feedstocks are at the root of bioindustrial production and are needed in greater quantities than ever due to increased prioritization of renewable fuels with reduced carbon footprints. Cyanobacteria possess a number of features that make them well suited as an alternative feedstock crop in comparison to traditional terrestrial plant species. Recent advances in genetic engineering, as well as promising preliminary investigations of cyanobacteria in a number of distinct production regimes have illustrated the potential of these aquatic phototrophs as biosynthetic chassis. Further improvements in strain productivities and design, along with enhanced understanding of photosynthetic metabolism in cyanobacteria may pave the way to translate cyanobacterial theoretical potential into realized application.

  11. Culturing photosynthetic bacteria through surface plasmon resonance

    Energy Technology Data Exchange (ETDEWEB)

    Ooms, Matthew D.; Bajin, Lauren; Sinton, David [Department of Mechanical and Industrial Engineering and Centre for Sustainable Energy, University of Toronto, Toronto M5S 3G8 (Canada)

    2012-12-17

    In this work, cultivation of photosynthetic microbes in surface plasmon enhanced evanescent fields is demonstrated. Proliferation of Synechococcus elongatus was obtained on gold surfaces excited with surface plasmons. Excitation over three days resulted in 10 {mu}m thick biofilms with maximum cell volume density of 20% vol/vol (2% more total accumulation than control experiments with direct light). Collectively, these results indicate the ability to (1) excite surface-bound cells using plasmonic light fields, and (2) subsequently grow thick biofilms by coupling light from the surface. Plasmonic light delivery presents opportunities for high-density optofluidic photobioreactors for microalgal analysis and solar fuel production.

  12. Surface modification of chitosan/PEO nanofibers by air dielectric barrier discharge plasma for acetylcholinesterase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Dorraki, Naghme, E-mail: n.dorraki@web.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Safa, Nasrin Navab [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Jahanfar, Mehdi [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of)

    2015-09-15

    Highlights: • We used an economical and effective method for surface modification. • Chitosan/PEO nanofibrous membranes were modified by air-DBD plasma. • The most NH{sub 3}{sup +} group was generated on the 6 min plasma modified membrane. • We immobilized acetylcholinesterase on the plasma modified and unmodified membranes. • More enzyme activity was detected on the modified membrane by plasma. - Abstract: There are different methods to modify polymer surfaces for biological applications. In this work we have introduced air-dielectric barrier discharge (DBD) plasma at atmospheric pressure as an economical and safe method for modifying the surface of electrospun chitosan/PEO (90/10) nanofibers for acetylcholinesterase (AChE) immobilization. According to the contact angle measurement results, the nanofibers become highly hydrophilic when they are exposed to the DBD plasma for 6 min in compared to unmodified membrane. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results reveal hydroxyl, C=O and NH{sub 3}{sup +} polar groups increment after 6 min plasma treatment. Contact angle measurements and ATR-FTIR results are confirmed by X-ray photoelectron spectroscopy (XPS). AChE at pH 7.4 carries a negative charge and after immobilization on the surface of plasma-treated nanofibrous membrane attracts the NH{sub 3}{sup +} group and more enzyme activity is detected on the plasma-modified nanofibers for 6 min in compared to unmodified nanofibers. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used for the surface topography and morphology characterization. The results have proved that air-DBD plasma is a suitable method for chitosan/PEO nanofibrous membrane modification as a biodegradable and functionalized substrate for enzyme immobilization.

  13. Differential Mobility of Pigment-Protein Complexes in Granal and Agranal Thylakoid Membranes of C-3 and C-4 Plants

    Czech Academy of Sciences Publication Activity Database

    Kirchhoff, H.; Sharpe, R.M.; Herbstová, Miroslava; Yarbrough, R.; Edwards, G.E.

    2013-01-01

    Roč. 161, č. 1 (2013), s. 497-507 ISSN 0032-0889 Institutional support: RVO:60077344 Keywords : Photosystem-II * Photosynthetic membranes * Electron tomography Subject RIV: ED - Physiology Impact factor: 7.394, year: 2013

  14. Sustained photosynthetic performance of Coffea spp. under long-term enhanced [CO2].

    Directory of Open Access Journals (Sweden)

    José C Ramalho

    Full Text Available Coffee is one of the world's most traded agricultural products. Modeling studies have predicted that climate change will have a strong impact on the suitability of current cultivation areas, but these studies have not anticipated possible mitigating effects of the elevated atmospheric [CO2] because no information exists for the coffee plant. Potted plants from two genotypes of Coffea arabica and one of C. canephora were grown under controlled conditions of irradiance (800 μmol m(-2 s(-1, RH (75% and 380 or 700 μL CO2 L(-1 for 1 year, without water, nutrient or root development restrictions. In all genotypes, the high [CO2] treatment promoted opposite trends for stomatal density and size, which decreased and increased, respectively. Regardless of the genotype or the growth [CO2], the net rate of CO2 assimilation increased (34-49% when measured at 700 than at 380 μL CO2 L(-1. This result, together with the almost unchanged stomatal conductance, led to an instantaneous water use efficiency increase. The results also showed a reinforcement of photosynthetic (and respiratory components, namely thylakoid electron transport and the activities of RuBisCo, ribulose 5-phosphate kinase, malate dehydrogenase and pyruvate kinase, what may have contributed to the enhancements in the maximum rates of electron transport, carboxylation and photosynthetic capacity under elevated [CO2], although these responses were genotype dependent. The photosystem II efficiency, energy driven to photochemical events, non-structural carbohydrates, photosynthetic pigment and membrane permeability did not respond to [CO2] supply. Some alterations in total fatty acid content and the unsaturation level of the chloroplast membranes were noted but, apparently, did not affect photosynthetic functioning. Despite some differences among the genotypes, no clear species-dependent responses to elevated [CO2] were observed. Overall, as no apparent sign of photosynthetic down

  15. Sustained Photosynthetic Performance of Coffea spp. under Long-Term Enhanced [CO2

    Science.gov (United States)

    Ramalho, José C.; Rodrigues, Ana P.; Semedo, José N.; Pais, Isabel P.; Martins, Lima D.; Simões-Costa, Maria C.; Leitão, António E.; Fortunato, Ana S.; Batista-Santos, Paula; Palos, Isabel M.; Tomaz, Marcelo A.; Scotti-Campos, Paula; Lidon, Fernando C.; DaMatta, Fábio M.

    2013-01-01

    Coffee is one of the world’s most traded agricultural products. Modeling studies have predicted that climate change will have a strong impact on the suitability of current cultivation areas, but these studies have not anticipated possible mitigating effects of the elevated atmospheric [CO2] because no information exists for the coffee plant. Potted plants from two genotypes of Coffea arabica and one of C. canephora were grown under controlled conditions of irradiance (800 μmol m-2 s-1), RH (75%) and 380 or 700 μL CO2 L-1 for 1 year, without water, nutrient or root development restrictions. In all genotypes, the high [CO2] treatment promoted opposite trends for stomatal density and size, which decreased and increased, respectively. Regardless of the genotype or the growth [CO2], the net rate of CO2 assimilation increased (34-49%) when measured at 700 than at 380 μL CO2 L-1. This result, together with the almost unchanged stomatal conductance, led to an instantaneous water use efficiency increase. The results also showed a reinforcement of photosynthetic (and respiratory) components, namely thylakoid electron transport and the activities of RuBisCo, ribulose 5-phosphate kinase, malate dehydrogenase and pyruvate kinase, what may have contributed to the enhancements in the maximum rates of electron transport, carboxylation and photosynthetic capacity under elevated [CO2], although these responses were genotype dependent. The photosystem II efficiency, energy driven to photochemical events, non-structural carbohydrates, photosynthetic pigment and membrane permeability did not respond to [CO2] supply. Some alterations in total fatty acid content and the unsaturation level of the chloroplast membranes were noted but, apparently, did not affect photosynthetic functioning. Despite some differences among the genotypes, no clear species-dependent responses to elevated [CO2] were observed. Overall, as no apparent sign of photosynthetic down-regulation was found, our data

  16. Redox regulation of photosynthetic gene expression.

    Science.gov (United States)

    Queval, Guillaume; Foyer, Christine H

    2012-12-19

    Redox chemistry and redox regulation are central to the operation of photosynthesis and respiration. However, the roles of different oxidants and antioxidants in the regulation of photosynthetic or respiratory gene expression remain poorly understood. Leaf transcriptome profiles of a range of Arabidopsis thaliana genotypes that are deficient in either hydrogen peroxide processing enzymes or in low molecular weight antioxidant were therefore compared to determine how different antioxidant systems that process hydrogen peroxide influence transcripts encoding proteins targeted to the chloroplasts or mitochondria. Less than 10 per cent overlap was observed in the transcriptome patterns of leaves that are deficient in either photorespiratory (catalase (cat)2) or chloroplastic (thylakoid ascorbate peroxidase (tapx)) hydrogen peroxide processing. Transcripts encoding photosystem II (PSII) repair cycle components were lower in glutathione-deficient leaves, as were the thylakoid NAD(P)H (nicotinamide adenine dinucleotide (phosphate)) dehydrogenases (NDH) mRNAs. Some thylakoid NDH mRNAs were also less abundant in tAPX-deficient and ascorbate-deficient leaves. Transcripts encoding the external and internal respiratory NDHs were increased by low glutathione and low ascorbate. Regulation of transcripts encoding specific components of the photosynthetic and respiratory electron transport chains by hydrogen peroxide, ascorbate and glutathione may serve to balance non-cyclic and cyclic electron flow pathways in relation to oxidant production and reductant availability.

  17. Respiratory processes in non-photosynthetic plastids

    Science.gov (United States)

    Renato, Marta; Boronat, Albert; Azcón-Bieto, Joaquín

    2015-01-01

    Chlororespiration is a respiratory process located in chloroplast thylakoids which consists in an electron transport chain from NAD(P)H to oxygen. This respiratory chain involves the NAD(P)H dehydrogenase complex, the plastoquinone pool and the plastid terminal oxidase (PTOX), and it probably acts as a safety valve to prevent the over-reduction of the photosynthetic machinery in stress conditions. The existence of a similar respiratory activity in non-photosynthetic plastids has been less studied. Recently, it has been reported that tomato fruit chromoplasts present an oxygen consumption activity linked to ATP synthesis. Etioplasts and amyloplasts contain several electron carriers and some subunits of the ATP synthase, so they could harbor a similar respiratory process. This review provides an update on the study about respiratory processes in chromoplasts, identifying the major gaps that need to be addressed in future research. It also reviews the proteomic data of etioplasts and amyloplasts, which suggest the presence of a respiratory electron transport chain in these plastids. PMID:26236317

  18. Respiratory processes in non-photosynthetic plastids

    Directory of Open Access Journals (Sweden)

    Marta eRenato

    2015-07-01

    Full Text Available Chlororespiration is a respiratory process located in chloroplast thylakoids which consists in an electron transport chain from NAD(PH to oxygen. This respiratory chain involves the NAD(PH dehydrogenase complex, the plastoquinone pool and the plastid terminal oxidase (PTOX, and it probably acts as a safety valve to prevent the over-reduction of the photosynthetic machinery in stress conditions. The existence of a similar respiratory activity in non-photosynthetic plastids has been less studied. Recently, it has been reported that tomato fruit chromoplasts present an oxygen consumption activity linked to ATP synthesis. Etioplasts and amyloplasts contain several electron carriers and some subunits of the ATP synthase, so they could harbor a similar respiratory process. This review provides an update on the study about respiratory processes in chromoplasts, identifying the major gaps that need to be addressed in future research. It also reviews the proteomic data of etioplasts and amyloplasts, which suggest the presence of a respiratory electron transport chain in these plastids.

  19. Photosynthetic pathways of some aquatic plants

    Energy Technology Data Exchange (ETDEWEB)

    Hough, R A [Wayne State Univ., Detroit; Wetzel, R G

    1977-12-01

    Over 40 species of aquatic angiosperms, including submersed, floating and emergent types, have been examined for photosynthetic status as part of a search for possible aquatic C/sub 4/ species. The C/sub 4/ system is viewed as potentially of adaptive value in certain aquatic situations, although evidence for its occurrence there is not conclusive. Emphasis was on plants from North-temperate softwater and hardwater lakes to explore both possibilities of CO/sub 2/ limitation, i.e., low total inorganic carbon in softwater vs. low free CO/sub 2/ in hardwater lakes. On the basis of leaf cross-section anatomy, all plants examined, with one exception, clearly did not show evidence of C/sub 4/ ''Krantz anatomy.'' In the submersed plant Potamogeton praelongus Wulf, large starch-producing chloroplasts were concentrated in cells surrounding vascular bundles and in a narrow band of cells between vascular bundles. The in situ photosynthetic rate of this plant was twice that of a related species, but other evidence including PEP carboxylase content and photorespiratory response to high O/sub 2/ did not confirm the presence of the C/sub 4/ photosynthesis.

  20. Stabilization and immobilization of aquaporin reconstituted lipid vesicles for water purification.

    Science.gov (United States)

    Sun, Guofei; Chung, Tai-Shung; Jeyaseelan, Kandiah; Armugam, Arunmozhiarasi

    2013-02-01

    Aquaporins are water channel proteins in biological membranes that have extraordinary water permeability and selectivity. In this work, we have demonstrated that one of their family members, AquaporinZ (AqpZ), can be possibly applied in a pressure-driven water purification process. A nanofiltration membrane was designed and fabricated by immobilization of AqpZ-reconstituted liposomes on a polydopamine (PDA) coated microporous membrane. Amine-functionalized proteoliposomes were first deposited via gentle vacuum suction and subsequently conjugated on the PDA layer via an amine-catechol adduct formation. Due to the existence of a polymer network within the lipid bilayers, the membrane could sustain hydraulic pressure of 5 bar as well as the strong surface agitation in nanofiltration tests, indicating a relatively stable membrane structure. In comparison with membrane without AqpZ incorporation, the membrane with AqpZ-to-lipid weight ratio of 1:100 increased the water flux by 65% with enhanced NaCl and MgCl(2) rejections of 66.2% and 88.1%, respectively. With AqpZ incorporation, the vesicle immobilized membrane exhibits a promising strategy for high productivity water purification. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Effects of immobilization and remobilization on the ankle joint in Wistar rats

    International Nuclear Information System (INIS)

    Kunz, R.I.; Coradini, J.G.; Silva, L.I.; Bertolini, G.R.F.; Brancalhão, R.M.C.; Ribeiro, L.F.C.

    2014-01-01

    A sprained ankle is a common musculoskeletal sports injury and it is often treated by immobilization of the joint. Despite the beneficial effects of this therapeutic measure, the high prevalence of residual symptoms affects the quality of life, and remobilization of the joint can reverse this situation. The aim of this study was to analyze the effects of immobilization and remobilization on the ankle joint of Wistar rats. Eighteen male rats had their right hindlimb immobilized for 15 days, and were divided into the following groups: G1, immobilized; G2, remobilized freely for 14 days; and G3, remobilized by swimming and jumping in water for 14 days, performed on alternate days, with progression of time and a series of exercises. The contralateral limb was the control. After the experimental period, the ankle joints were processed for microscopic analysis. Histomorphometry did not show any significant differences between the control and immobilized/remobilized groups and members, in terms of number of chondrocytes and thickness of the articular cartilage of the tibia and talus. Morphological analysis of animals from G1 showed significant degenerative lesions in the talus, such as exposure of the subchondral bone, flocculation, and cracks between the anterior and mid-regions of the articular cartilage and the synovial membrane. Remobilization by therapeutic exercise in water led to recovery in the articular cartilage and synovial membrane of the ankle joint when compared with free remobilization, and it was shown to be an effective therapeutic measure in the recovery of the ankle joint

  2. Contribution of Extracellular Polymeric Substances from Shewanella sp. HRCR-1 Biofilms to U(VI) Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Bin; Ahmed, B.; Kennedy, David W.; Wang, Zheming; Shi, Liang; Marshall, Matthew J.; Fredrickson, Jim K.; Isern, Nancy G.; Majors, Paul D.; Beyenal, Haluk

    2011-06-05

    The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) in U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells without EPS, we showed that i) bEPS from Shewanella sp. HRCR-1 biofilms contributed significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; ii) bEPS could be considered as a functional extension of the cells for U(VI) immobilization and they likely play more important roles at initial U(VI) concentrations; and iii) U(VI) reduction efficiency was found to be dependent upon initial U(VI) concentration and the efficiency decreased at lower concentrations. To quantify relative contribution of sorption and reduction in U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(V). We found that, when in reduced form, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated reactivity of laEPS while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, might facilitate U(VI) reduction.

  3. Effects of immobilization and remobilization on the ankle joint in Wistar rats

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, R.I. [Laboratório de Biologia Estrutural e Funcional, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil); Coradini, J.G.; Silva, L.I.; Bertolini, G.R.F. [Laboratório do Estudo das Lesões e Recursos Fisioterapêuticos, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil); Brancalhão, R.M.C.; Ribeiro, L.F.C. [Laboratório de Biologia Estrutural e Funcional, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil)

    2014-08-15

    A sprained ankle is a common musculoskeletal sports injury and it is often treated by immobilization of the joint. Despite the beneficial effects of this therapeutic measure, the high prevalence of residual symptoms affects the quality of life, and remobilization of the joint can reverse this situation. The aim of this study was to analyze the effects of immobilization and remobilization on the ankle joint of Wistar rats. Eighteen male rats had their right hindlimb immobilized for 15 days, and were divided into the following groups: G1, immobilized; G2, remobilized freely for 14 days; and G3, remobilized by swimming and jumping in water for 14 days, performed on alternate days, with progression of time and a series of exercises. The contralateral limb was the control. After the experimental period, the ankle joints were processed for microscopic analysis. Histomorphometry did not show any significant differences between the control and immobilized/remobilized groups and members, in terms of number of chondrocytes and thickness of the articular cartilage of the tibia and talus. Morphological analysis of animals from G1 showed significant degenerative lesions in the talus, such as exposure of the subchondral bone, flocculation, and cracks between the anterior and mid-regions of the articular cartilage and the synovial membrane. Remobilization by therapeutic exercise in water led to recovery in the articular cartilage and synovial membrane of the ankle joint when compared with free remobilization, and it was shown to be an effective therapeutic measure in the recovery of the ankle joint.

  4. Contribution of extracellular polymeric substances from Shewanella sp. HRCR-1 biofilms to U(VI) immobilization.

    Science.gov (United States)

    Cao, Bin; Ahmed, Bulbul; Kennedy, David W; Wang, Zheming; Shi, Liang; Marshall, Matthew J; Fredrickson, Jim K; Isern, Nancy G; Majors, Paul D; Beyenal, Haluk

    2011-07-01

    The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) to U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells with minimal EPS, we show that (i) bEPS from Shewanella sp. HRCR-1 biofilms contribute significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; (ii) bEPS can be considered a functional extension of the cells for U(VI) immobilization and they likely play more important roles at lower initial U(VI) concentrations; and (iii) the U(VI) reduction efficiency is dependent upon the initial U(VI) concentration and decreases at lower concentrations. To quantify the relative contributions of sorption and reduction to U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(VI). We found that, when reduced, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated the reactivity of laEPS, while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, possibly facilitated U(VI) reduction.

  5. Evidence for high-pressure-induced rupture of hydrogen bonds in LH2 photosynthetic antenna pigment-protein complexes

    International Nuclear Information System (INIS)

    Kangur, L; Leiger, K; Freiberg, A

    2008-01-01

    The bacteriochlorophyll a-containing LH2 light harvesting complex is an integral membrane protein that catalyzes the photosynthetic process in purple photosynthetic bacteria. The LH2 complexes from Rhodobacter sphaeroides show characteristic strong absorbance at 800 and 850 nm due to the bacteriochlorophyll a molecules confined in two separate areas of the protein. Using these cofactors as intrinsic probes to monitor changes in membrane protein structure, we investigate the response to high hydrostatic pressure up to 2.1 GPa of LH2 complexes embedded into natural membrane environment or extracted with detergent. We demonstrate that high pressure does induce significant alterations to the tertiary structure of the protein in proximity of the protein-bound bacteriochlorophyll a molecules, including breakage of the hydrogen bond they are involved in. The membrane-embedded complexes appear more resilient to damaging effects of the compression than the complexes extracted into detergent environment. This difference has tentatively been explained by more compact structure of the membrane-embedded complexes

  6. Evidence for high-pressure-induced rupture of hydrogen bonds in LH2 photosynthetic antenna pigment-protein complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kangur, L; Leiger, K; Freiberg, A [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia)

    2008-07-15

    The bacteriochlorophyll a-containing LH2 light harvesting complex is an integral membrane protein that catalyzes the photosynthetic process in purple photosynthetic bacteria. The LH2 complexes from Rhodobacter sphaeroides show characteristic strong absorbance at 800 and 850 nm due to the bacteriochlorophyll a molecules confined in two separate areas of the protein. Using these cofactors as intrinsic probes to monitor changes in membrane protein structure, we investigate the response to high hydrostatic pressure up to 2.1 GPa of LH2 complexes embedded into natural membrane environment or extracted with detergent. We demonstrate that high pressure does induce significant alterations to the tertiary structure of the protein in proximity of the protein-bound bacteriochlorophyll a molecules, including breakage of the hydrogen bond they are involved in. The membrane-embedded complexes appear more resilient to damaging effects of the compression than the complexes extracted into detergent environment. This difference has tentatively been explained by more compact structure of the membrane-embedded complexes.

  7. Immobilization of iodine in concrete

    Science.gov (United States)

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  8. Global Proteomic Analysis Reveals an Exclusive Role of Thylakoid Membranes in Bioenergetics of a Model Cyanobacterium

    Energy Technology Data Exchange (ETDEWEB)

    Liberton, Michelle; Saha, Rajib; Jacobs, Jon M.; Nguyen, Amelia Y.; Gritsenko, Marina A.; Smith, Richard D.; Koppenaal, David W.; Pakrasi, Himadri B.

    2016-04-07

    Cyanobacteria are photosynthetic microbes with highly differentiated membrane systems. These organisms contain an outer membrane, plasma membrane, and an internal system of thylakoid membranes where the photosynthetic and respiratory machinery are found. This existence of compartmentalization and differentiation of membrane systems poses a number of challenges for cyanobacterial cells in terms of organization and distribution of proteins to the correct membrane system. Proteomics studies have long sought to identify the components of the different membrane systems, and to date about 450 different proteins have been attributed to either the plasma membrane or thylakoid membrane. Given the complexity of these membranes, many more proteins remain to be identified in these membrane systems, and a comprehensive catalog of plasma membrane and thylakoid membrane proteins is needed. Here we describe the identification of 635 proteins in Synechocystis sp. PCC 6803 by quantitative iTRAQ isobaric labeling; of these, 459 proteins were localized to the plasma membrane and 176 were localized to the thylakoid membrane. Surprisingly, we found over 2.5 times the number of unique proteins identified in the plasma membrane compared to the thylakoid membrane. This suggests that the protein composition of the thylakoid membrane is more homogeneous than the plasma membrane, consistent with the role of the plasma membrane in diverse cellular processes including protein trafficking and nutrient import, compared to a more specialized role for the thylakoid membrane in cellular energetics. Overall, the protein composition of the Synechocystis 6803 plasma membrane and thylakoid membrane is quite similar to the E.coli plasma membrane and Arabidopsis thylakoid membrane, respectively. Synechocystis 6803 can therefore be described as a gram-negative bacterium that has an additional internal membrane system that fulfils the energetic requirements of the cell.

  9. Global Proteomic Analysis Reveals an Exclusive Role of Thylakoid Membranes in Bioenergetics of a Model Cyanobacterium

    Energy Technology Data Exchange (ETDEWEB)

    Liberton, Michelle; Saha, Rajib; Jacobs, Jon M.; Nguyen, Amelia Y.; Gritsenko, Marina A.; Smith, Richard D.; Koppenaal, David W.; Pakrasi, Himadri B.

    2016-04-07

    Cyanobacteria are photosynthetic microbes with highlydifferentiated membrane systems. These organisms contain an outer membrane, plasma membrane, and an internal system of thylakoid membranes where the photosynthetic and respiratory machinery are found. This existence of compartmentalization and differentiation of membrane systems poses a number of challenges for cyanobacterial cells in terms of organization and distribution of proteins to the correct membrane system. Proteomics studies have long sought to identify the components of the different membrane systems in cyanobacteria, and to date about 450 different proteins have been attributed to either the plasma membrane or thylakoid membrane. Given the complexity of these membranes, many more proteins remain to be identified, and a comprehensive catalogue of plasma membrane and thylakoid membrane proteins is needed. Here we describe the identification of 635 differentially localized proteins in Synechocystis sp. PCC 6803 by quantitative iTRAQ isobaric labeling; of these, 459 proteins were localized to the plasma membrane and 176 were localized to the thylakoid membrane. Surprisingly, we found over 2.5 times the number of unique proteins identified in the plasma membrane compared with the thylakoid membrane. This suggests that the protein composition of the thylakoid membrane is more homogeneous than the plasma membrane, consistent with the role of the plasma membrane in diverse cellular processes including protein trafficking and nutrient import, compared with a more specialized role for the thylakoid membrane in cellular energetics. Thus, our data clearly define the two membrane systems with distinct functions. Overall, the protein compositions of the Synechocystis 6803 plasma membrane and thylakoid membrane are quite similar to that of the plasma membrane of Escherichia coli and thylakoid membrane of Arabidopsis chloroplasts, respectively. Synechocystis 6803 can therefore be described as a Gram

  10. Contaminant immobilization via microbial activity

    International Nuclear Information System (INIS)

    1991-11-01

    The aim of this study was to search the literature to identify biological techniques that could be applied to the restoration of contaminated groundwaters near uranium milling sites. Through bioremediation it was hypothesized that the hazardous heavy metals could be immobilized in a stable, low-solubility form, thereby halting their progress in the migrating groundwater. Three basic mechanisms were examined: reduction of heavy metals by microbially produced hydrogen sulfide; direct microbial mediated reduction; and biosorption

  11. Immobilization of iodine in concrete

    International Nuclear Information System (INIS)

    Clark, W.E.; Thompson, C.T.

    1977-01-01

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3 to 20 wt percent iodine as Ba(IO 3 ) 2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO 3 ) 2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. 10 claims, 2 figures

  12. The effect of nitrogen on the development and photosynthetic activity ...

    African Journals Online (AJOL)

    Whole plant net photosynthetic rates appeared to vary according to the units in which the activity is expressed. The optimum levels of photosynthetic activity differed with the stage of development, depending on the basis of expression. The form and concentration of nitrogen applied influenced morphological development ...

  13. Research on spatial distribution of photosynthetic characteristics of Winter Wheat

    Science.gov (United States)

    Yan, Q. Q.; Zhou, Q. Y.; Zhang, B. Z.; Han, X.; Han, N. N.; Li, S. M.

    2018-03-01

    In order to explore the spatial distribution of photosynthetic characteristics of winter wheat leaf, the photosynthetic rate on different parts of leaf (leaf base-leaf middle-leaf apex) and that on each canopy (top layer-middle layer-bottom layer) leaf during the whole growth period of winter wheat were measured. The variation of photosynthetic rate with PAR and the spatial distribution of winter wheat leaf during the whole growth periods were analysed. The results showed that the photosynthetic rate of different parts of winter wheat increased with the increase of PAR, which was showed as leaf base>leaf middle>leaf apex. In the same growth period, photosynthetic rate in different parts of the tablet was showed as leaf middle>leaf base>leaf apex. For the different canopy layer of winter wheat, the photosynthetic rate of the top layer leaf was significantly greater than that of the middle layer and lower layer leaf. The photosynthetic rate of the top layer leaf was the largest in the leaf base position. The photosynthetic rate of leaf of the same canopy layer at different growth stages were showed as tasseling stage >grain filling stage > maturation stage.

  14. 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....

  15. [THE EFFECT OF ACID RAIN ON ULTRASTRUCTURE AND FUNCTIONAL PARAMETERS OF PHOTOSYNTHETIC APPARATUS OF PEA LEAVES].

    Science.gov (United States)

    Polishchuk, A V; Vodka, M V; Belyavskaya, N A; Khomochkin, A P; Zolotareva, E K

    2016-01-01

    The effects of simulated acid rain (SAR) on the ultrastructure and functional parameters of the photosynthetic apparatus were studied using 14-day-old pea leaves as test system. Pea plants were sprayed with an aqueous solution containing NaNO₃(0.2 mM) and Na₂SO₄(0.2 mM) (pH 5.6, a control variant), or with the same solution, which was acidified to pH 2.5 (acid variant). Functional characteristics were determined by chlorophyll fluorescence analysis. Acid rain application caused reduction in the efficiency of the photosynthetic electron transport by 25%, which was accompanied by an increase by 85% in the quantum yield of thermal dissipation of excess light quanta. Ultrastructural changes in chloroplast were registered by transmission electron microscopy (TEM) after two days of the SAR-treatment of pea leaves. In this case, the changes in the structure of grana, heterogeneity of thylakoids packaging in granum, namely, the increase of intra-thylakoid gaps and thickness of granal thylakoids compared to the control were found. The migration of protein complexes in thylakoid membranes of chloroplasts isolated from leaves treated with SAR was suppressed. It was shown also that carbonic anhydrase activity was inhibited in chloroplast preparations isolated from SAR-treated pea leaves. We proposed a hypothesis on the possible inactivation of thylakoid carbonic anhydrase under SAR and its involvement in the inhibition of photochemical activity of chloroplasts. The data obtained allows to suggest that acid rains negatively affect the photosynthetic apparatus disrupting the membrane system of chloroplast.

  16. Effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of summer maize.

    Science.gov (United States)

    Ren, Baizhao; Cui, Haiyan; Camberato, James J; Dong, Shuting; Liu, Peng; Zhao, Bin; Zhang, Jiwang

    2016-08-01

    A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of mesophyll cell ultrastructure, chloroplast configuration of mesophyll cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in mesophyll cells and the endomembrane system was destroyed, which resulted in the dissolution of cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged mesophyll cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK.

  17. Porphyrin and fullerene-based artificial photosynthetic materials for photovoltaics

    International Nuclear Information System (INIS)

    Imahori, Hiroshi; Kashiwagi, Yukiyasu; Hasobe, Taku; Kimura, Makoto; Hanada, Takeshi; Nishimura, Yoshinobu; Yamazaki, Iwao; Araki, Yasuyuki; Ito, Osamu; Fukuzumi, Shunichi

    2004-01-01

    We have developed artificial photosynthetic systems in which porphyrins and fullerenes are self-assembled as building blocks into nanostructured molecular light-harvesting materials and photovoltaic devices. Multistep electron transfer strategy has been combined with our finding that porphyrin and fullerene systems have small reorganization energies, which are suitable for the construction of light energy conversion systems as well as artificial photosynthetic models. Highly efficient photosynthetic electron transfer reactions have been realized at ITO electrodes modified with self-assembled monolayers of porphyrin oligomers as well as porphyrin-fullerene linked systems. Porphyrin-modified gold nanoclusters have been found to have potential as artificial photosynthetic materials. These results provide basic information for the development of nanostructured artificial photosynthetic systems

  18. Morning reduction of photosynthetic capacity before midday depression.

    Science.gov (United States)

    Koyama, Kohei; Takemoto, Shuhei

    2014-03-17

    Midday depression of photosynthesis has important consequences for ecosystem carbon exchange. Recent studies of forest trees have demonstrated that latent reduction of photosynthetic capacity can begin in the early morning, preceding the midday depression. We investigated whether such early morning reduction also occurs in an herbaceous species, Oenothera biennis. Diurnal changes of the photosynthetic light response curve (measured using a light-emitting diode) and incident sunlight intensity were measured under field conditions. The following results were obtained: (1) the light-saturated photosynthetic rate decreased beginning at sunrise; (2) the incident sunlight intensity on the leaves increased from sunrise; and (3) combining (1) and (2), the net photosynthetic rate under natural sunlight intensity increased from sunrise, reached a maximum at mid-morning, and then showed midday depression. Our results demonstrate that the latent morning reduction of photosynthetic capacity begins at sunrise, preceding the apparent midday depression, in agreement with previous studies of forest trees.

  19. Photosynthetic Characteristics of Flag Leaves in Rice White Stripe Mutant 6001 During Senescence Process

    Directory of Open Access Journals (Sweden)

    Xiao-hui ZHEN

    2014-11-01

    Full Text Available Physiological, biochemical and electron microscopy analyses were used to investigate the photosynthetic performance of flag leaves in rice white stripe mutant 6001 during the senescence process. Results showed that the chlorophyll content at the heading and milk-ripe stages in rice mutant 6001 were about 34.78% and 3.00% less than those in wild type 6028, respectively. However, the chlorophyll content at the fully-ripe stage in rice mutant 6001 was higher than that in wild type 6028. At the heading stage, the net photosynthetic rate (Pn in rice mutant 6001 was lower than that in wild type 6028. Rice mutant 6001 also exhibited a significantly slower decrease rate of Pn than wild type 6028 during the senescence progress, especially at the later stage. Furthermore, Ca2+-ATPase, Mg2+-ATPase and photophosphorylation activities exhibited the similar trends as the Pn. During the senescence process, the 68 kDa polypeptide concentrations in the thylakoid membrane proteins exhibited a significant change, which was one of the critical factors that contributed to the observed change in photosynthesis. We also observed that the chloroplasts of rice mutant 6001 exhibited higher integrity than those of wild type 6028, and the chloroplast membrane of rice mutant 6001 disintegrated more slow during the senescence process. In general, rice mutant 6001 had a relatively slower senescence rate than wild type 6028, and exhibited anti-senescence properties.

  20. Effect of fluoride on the cell viability, cell organelle potential, and photosynthetic capacity of freshwater and soil algae.

    Science.gov (United States)

    Chae, Yooeun; Kim, Dokyung; An, Youn-Joo

    2016-12-01

    Although fluoride occurs naturally in the environment, excessive amounts of fluoride in freshwater and terrestrial ecosystems can be harmful. We evaluated the toxicity of fluoride compounds on the growth, viability, and photosynthetic capacity of freshwater (Chlamydomonas reinhardtii and Pseudokirchneriella subcapitata) and terrestrial (Chlorococcum infusionum) algae. To measure algal growth inhibition, a flow cytometric method was adopted (i.e., cell size, granularity, and auto-fluorescence measurements), and algal yield was calculated to assess cell viability. Rhodamine123 and fluorescein diacetate were used to evaluate mitochondrial membrane potential (MMA, ΔΨ m ) and cell permeability. Nine parameters related to the photosynthetic capacity of algae were also evaluated. The results indicated that high concentrations of fluoride compounds affected cell viability, cell organelle potential, and photosynthetic functions. The cell viability measurements of the three algal species decreased, but apoptosis was only observed in C. infusionum. The MMA (ΔΨ m ) of cells exposed to fluoride varied among species, and the cell permeability of the three species generally decreased. The decrease in the photosynthetic activity of algae may be attributable to the combination of fluoride ions (F - ) with magnesium ions (Mg 2+ ) in chlorophyll. Our results therefore provide strong evidence for the potential risks of fluoride compounds to microflora and microfauna in freshwater and terrestrial ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Diversity and abundance of photosynthetic sponges in temperate Western Australia

    Directory of Open Access Journals (Sweden)

    Brümmer Franz

    2009-02-01

    Full Text Available Abstract Background Photosynthetic sponges are important components of reef ecosystems around the world, but are poorly understood. It is often assumed that temperate regions have low diversity and abundance of photosynthetic sponges, but to date no studies have investigated this question. The aim of this study was to compare the percentages of photosynthetic sponges in temperate Western Australia (WA with previously published data on tropical regions, and to determine the abundance and diversity of these associations in a range of temperate environments. Results We sampled sponges on 5 m belt transects to determine the percentage of photosynthetic sponges and identified at least one representative of each group of symbionts using 16S rDNA sequencing together with microscopy techniques. Our results demonstrate that photosynthetic sponges are abundant in temperate WA, with an average of 63% of sponge individuals hosting high levels of photosynthetic symbionts and 11% with low to medium levels. These percentages of photosynthetic sponges are comparable to those found on tropical reefs and may have important implications for ecosystem function on temperate reefs in other areas of the world. A diverse range of symbionts sometimes occurred within a small geographic area, including the three "big" cyanobacterial clades, Oscillatoria spongeliae, "Candidatus Synechococcus spongiarum" and Synechocystis species, and it appears that these clades all occur in a wide range of sponges. Additionally, spongin-permeating red algae occurred in at least 7 sponge species. This study provides the first investigation of the molecular phylogeny of rhodophyte symbionts in sponges. Conclusion Photosynthetic sponges are abundant and diverse in temperate WA, with comparable percentages of photosynthetic to non-photosynthetic sponges to tropical zones. It appears that there are three common generalist clades of cyanobacterial symbionts of sponges which occur in a wide

  2. Membrane microdomains, rafts, and detergent-resistant membranes in plants and fungi.

    Science.gov (United States)

    Malinsky, Jan; Opekarová, Miroslava; Grossmann, Guido; Tanner, Widmar

    2013-01-01

    The existence of specialized microdomains in plasma membranes, postulated for almost 25 years, has been popularized by the concept of lipid or membrane rafts. The idea that detergent-resistant membranes are equivalent to lipid rafts, which was generally abandoned after a decade of vigorous data accumulation, contributed to intense discussions about the validity of the raft concept. The existence of membrane microdomains, meanwhile, has been verified by unequivocal independent evidence. This review summarizes the current state of research in plants and fungi with respect to common aspects of both kingdoms. In these organisms, principally immobile microdomains large enough for microscopic detection have been visualized. These microdomains are found in the context of cell-cell interactions (plant symbionts and pathogens), membrane transport, stress, and polarized growth, and the data corroborate at least three mechanisms of formation. As documented in this review, modern methods of visualization of lateral membrane compartments are also able to uncover the functional relevance of membrane microdomains.

  3. Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo

    2011-01-01

    In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique...

  4. Properties of immobilized papain by radiation polymerization

    International Nuclear Information System (INIS)

    Kumakura, Minoru; Kaetsu, Isao

    1984-01-01

    Papain was immobilized by the radiation polymerization of various monomers at low temperatures and the effects of the polymer matrix on the enzyme activity and thermal stability of the immobilized enzymes were studied. The activity of the immobilized enzymes prepared from monofunctional (acrylate and methacrylate) monomers was higher than that from bifunctional (bismethacrylate) monomers and that from polyoxyethylene dimethacrylate monomers increased with an increase in the number of oxyethylene units. The thermal stability of the immobilized enzymes prepared from hydrophilic monomers was higher than that from hydrophobic monomers and increased markedly with increasing monomer concentration. (author)

  5. Structure and membrane organization of photosystem II in green plants

    NARCIS (Netherlands)

    Hankamer, B; Barber, J; Boekema, EJ

    1997-01-01

    Photosystem II (PSII) is the pigment protein complex embedded in the thylakoid membrane of higher plants, algae, and cyanobacteria that uses solar energy to drive the photosynthetic water-splitting reaction. This chapter reviews the primary, secondary, tertiary, and quaternary structures of PSII as

  6. Photosynthetic properties of erect leaf maize inbred lines as the efficient photo-model in breeding and seed production

    Directory of Open Access Journals (Sweden)

    Radenović Čedomir N.

    2003-01-01

    Full Text Available The initial idea of this study was a hypothesis that erect leaf maize inbred lines were characterized by properties of an efficient photo-model and that as such were very desirable in increasing the number of plants per area unit (plant density in the process of contemporary selection and seed production. The application of a non-invasive bioluminescence-photosynthetic method, suitable for the efficiency estimation of the photo-model, verified the hypothesis. Obtained photosynthetic properties of observed erect leaf maize inbred lines were based on the effects and characteristics of thermal processes of delayed chlorophyll fluorescence occurring in their thylakoid membranes. The temperature dependence of the delayed chlorophyll fluorescence intensity phase transitions (critical temperatures in the thylakoid membranes and activation energy are the principal parameters of the thermal processes. Based on obtained photosynthetic properties it is possible to select erect leaf maize inbred lines that are resistant and tolerant to high and very high temperatures, as well as, to drought. They could be good and efficient photo-models wherewith.

  7. Lipids and pigment-protein complexes of photosynthetic apparatus of Deschampsia antarctica Desv. plants under UV-B radiation

    Directory of Open Access Journals (Sweden)

    Svietlova N. B.

    2012-01-01

    Full Text Available Aim. To investigate structural and functional modifications of major components of photosynthetic membranes of endemic antarctic species D. antarctica under UV-B radiation. Methods. For quantitative determination of photosynthetic membrane components we used Arnon’s method (for chlorophylls and carotenoids; separation of carotenoids was carried out by Merzlyak’s method; polar lipids were isolated by Zill and Harmon method in modification of Yakovenko and Mihno; glycolipids separation and identification we carried out by Yamamoto method; and sulfoquinovosyl diacylglycerol content was determined by Kean method. The separation, disintegration and determination of pigment-protein complexes of chloroplasts were carried out by Anderson method. Authenticity of differences between the mean arithmetic values of indices was set after the Student criterion. Differences were considered as reliable at p 0.05. Results. We determined structural and functional changes in lipids, carotenoids and pigment-protein complexes at the photosyntetic apparatus level in D. antarctica plants under UV-B radiation. Conclusions. Adaptation of D. antarctica plants to UV-B radiation is accompanied by a cascade of physiological and biochemical rearrangements at the level of photosynthetic apparatus, manifested as the changes in pigment, lipid and pigment-protein complexes content

  8. Impact of the lipid bilayer on energy transfer kinetics in the photosynthetic protein LH2.

    Science.gov (United States)

    Ogren, John I; Tong, Ashley L; Gordon, Samuel C; Chenu, Aurélia; Lu, Yue; Blankenship, Robert E; Cao, Jianshu; Schlau-Cohen, Gabriela S

    2018-03-28

    Photosynthetic purple bacteria convert solar energy to chemical energy with near unity quantum efficiency. The light-harvesting process begins with absorption of solar energy by an antenna protein called Light-Harvesting Complex 2 (LH2). Energy is subsequently transferred within LH2 and then through a network of additional light-harvesting proteins to a central location, termed the reaction center, where charge separation occurs. The energy transfer dynamics of LH2 are highly sensitive to intermolecular distances and relative organizations. As a result, minor structural perturbations can cause significant changes in these dynamics. Previous experiments have primarily been performed in two ways. One uses non-native samples where LH2 is solubilized in detergent, which can alter protein structure. The other uses complex membranes that contain multiple proteins within a large lipid area, which make it difficult to identify and distinguish perturbations caused by protein-protein interactions and lipid-protein interactions. Here, we introduce the use of the biochemical platform of model membrane discs to study the energy transfer dynamics of photosynthetic light-harvesting complexes in a near-native environment. We incorporate a single LH2 from Rhodobacter sphaeroides into membrane discs that provide a spectroscopically amenable sample in an environment more physiological than detergent but less complex than traditional membranes. This provides a simplified system to understand an individual protein and how the lipid-protein interaction affects energy transfer dynamics. We compare the energy transfer rates of detergent-solubilized LH2 with those of LH2 in membrane discs using transient absorption spectroscopy and transient absorption anisotropy. For one key energy transfer step in LH2, we observe a 30% enhancement of the rate for LH2 in membrane discs compared to that in detergent. Based on experimental results and theoretical modeling, we attribute this difference to

  9. Monte Carlo simulations of protein micropatterning in biomembranes: effects of immobile sticky obstacles

    International Nuclear Information System (INIS)

    Arnold, Andreas M; Sevcsik, Eva; Schütz, Gerhard J

    2016-01-01

    Single molecule trajectories of lipids and proteins can yield valuable information about the nanoscopic organization of the plasma membrane itself. The interpretation of such trajectories, however, is complicated, as the mobility of molecules can be affected by the presence of immobile obstacles, and the transient binding of the tracers to these obstacles. We have previously developed a micropatterning approach that allows for immobilizing a plasma membrane protein and probing the diffusional behavior of a putative interaction partner in living cells. Here, we provide guidelines on how this micropatterning approach can be extended to quantify interaction parameters between plasma membrane constituents in their natural environment. We simulated a patterned membrane system and evaluated the effect of different surface densities of patterned immobile obstacles on the relative mobility as well as the surface density of diffusing tracers. In the case of inert obstacles, the size of the obstacle can be assessed from its surface density at the percolation threshold, which in turn can be extracted from the diffusion behavior of the tracer. For sticky obstacles, 2D dissociation constants can be determined from the tracer diffusion or surface density. (paper)

  10. Supported liquid inorganic membranes for nuclear waste separation

    Science.gov (United States)

    Bhave, Ramesh R; DeBusk, Melanie M; DelCul, Guillermo D; Delmau, Laetitia H; Narula, Chaitanya K

    2015-04-07

    A system and method for the extraction of americium from radioactive waste solutions. The method includes the transfer of highly oxidized americium from an acidic aqueous feed solution through an immobilized liquid membrane to an organic receiving solvent, for example tributyl phosphate. The immobilized liquid membrane includes porous support and separating layers loaded with tributyl phosphate. The extracted solution is subsequently stripped of americium and recycled at the immobilized liquid membrane as neat tributyl phosphate for the continuous extraction of americium. The sequestered americium can be used as a nuclear fuel, a nuclear fuel component or a radiation source, and the remaining constituent elements in the aqueous feed solution can be stored in glassified waste forms substantially free of americium.

  11. Production of Biodiesel Using Immobilized Lipase and the Characterization of Different Co-Immobilizing Agents and Immobilization Methods

    Directory of Open Access Journals (Sweden)

    Kang Zhao

    2016-08-01

    Full Text Available Lipase from Candida sp. 99–125 is widely employed to catalyzed transesterification and can be used for biodiesel production. In this study, the lipase was immobilized by combined adsorption and entrapment to catalyze biodiesel production from waste cooking oil (WCO via transesterification, and investigating co-immobilizing agents as additives according to the enzyme activity. The addition of the mixed co-immobilizing agents has positive effects on the activities of the immobilized lipase. Three different immobilizing methods were compared by the conversion ratio of biodiesel and structured by Atom Force Microscopy (AFM and Scanning Electron Microscopy (SEM, respectively. It was found that entrapment followed by adsorption was the best method. The effect of the co-immobilizing agent amount, lipase dosage, water content, and reuse ability of the immobilized lipase was investigated. By comparison with previous research, this immobilized lipase showed good reuse ability: the conversion ratio excesses 70% after 10 subsequent reactions, in particular, was better than Novozym435 and TLIM on waste cooking oil for one unit of lipase.

  12. Preparation of thermo-responsive membranes. II.

    Science.gov (United States)

    Nozawa, I; Suzuki, Y; Sato, S; Sugibayashi, K; Morimoto, Y

    1991-05-01

    Two types of liquid crystal (LC)-immobilized membranes were prepared by a soaking method and sandwich method to control the permeation of indomethacin, as a model drug, in response to local and systemic fever. Monooxyethylene trimethylolpropane tristearate (MTTS) was used as a model LC because it has a gel-liquid crystal phase transition temperature near the body temperature, 39-40 degrees C in phosphate buffered saline (pH 7.4). Two porous polypropylene (PP) membranes were soaked into 20% MTTS chloroform solution in the soaking method, and two PP membranes were poured with the melted MTTS and pressed in the sandwich method. Thermo-response efficacy of the soaked membrane was dependent upon the content of MTTS in MTTS membrane, and the MTTS content above the void volume of PP membrane (38%) was needed for high efficacy. On the other hand, the sandwich membrane exhibited higher thermo-response efficacy than the soaked membrane, because more LC was embedded in the pores of sandwich membrane than that of the soaked membrane. The sandwich membrane permeation of indomethacin was sharply controlled by temperature changes between 32 and 38 degrees C.

  13. Ecological-photosynthetic system for the treatment of swine wastewater in farm; Proceso ecologico-fotosintetico para la depuracion de purines en grajas

    Energy Technology Data Exchange (ETDEWEB)

    Duran Barrantes, M. M.; Alvarez Mateos, P.; Carta Escobar, F.; Romero guzman, F. [Universidad de Sevilla (Spain); Fiestas Ros de Ursinos, J. A. [Instituto de la Grasa. Sevilla (Spain)

    2000-07-01

    The Ecological-Photosynthetic System (Paten n. 8901368, C.S.I.C.) is a low cost process of operational simplicity; his only energetic source is solar radiation. It is based on the ecological development of different communities of microorganisms in order to avoid negative interactions between them, immobilized on clayey support. The present work went in pursuit of the study of an integral biological plant in a piggery farm, from October of 1993 to June of 1995. Its high purification performance and nil running costs make it ideal for treating waste water from small farms. (Author) 13 refs.

  14. Forced-flow bioreactor for sucrose inversion using ceramic membrane activated by silanization.

    Science.gov (United States)

    Nakajima, M; Watanabe, A; Jimbo, N; Nishizawa, K; Nakao, S

    1989-02-20

    A forced-flow enzyme membrane reactor system for sucrose inversion was investigated using three ceramic membranes having different pore sizes. Invertase was immobilized chemically to the inner surface of a ceramic membrane activated by a silane-glutaraldehyde technique. With the cross-flow filtration of sucrose solution, the reaction rate was a function of the permeate flux, easily controlled by pressure. Using 0.5 microm support pore size of membrane, the volumetric productivity obtained was 10 times higher than that in a reported immobilized enzyme column reactor, with a short residence time of 5 s and 100% conversion of the sucrose inversion.

  15. Technetium Immobilization Forms Literature Survey

    Energy Technology Data Exchange (ETDEWEB)

    Westsik, Joseph H.; Cantrell, Kirk J.; Serne, R. Jeffrey; Qafoku, Nikolla

    2014-05-01

    Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.

  16. Photosynthetic electron transport in thylakoid preparations from two marine red algae (Rhodophyta).

    Science.gov (United States)

    Stewart, A C; Larkum, A W

    1983-01-01

    Thylakoid membrane preparations active in photosynthetic electron transport have been obtained from two marine red algae, Griffithsia monilis and Anotrichium tenue. High concentrations (0.5-1.0 M) of salts such as phosphate, citrate, succinate and tartrate stabilized functional binding of phycobilisomes to the membrane and also stabilized Photosystem II-catalysed electron-transport activity. High concentrations (1.0 M) of chloride and nitrate, or 30 mM-Tricine/NaOH buffer (pH 7.2) in the absence of salts, detached phycobilisomes and inhibited electron transport through Photosystem II. The O2-evolving system was identified as the electron-transport chain component that was inhibited under these conditions. Washing membranes with buffers containing 1.0-1.5 M-sorbitol and 5-50 mM concentrations of various salts removed the outer part of the phycobilisome but retained 30-70% of the allophycocyanin 'core' of the phycobilisome. These preparations were 30-70% active in O2 evolution compared with unwashed membranes. In the sensitivity of their O2-evolving apparatus to the composition of the medium in vitro, the red algae resembled blue-green algae and differed from other eukaryotic algae and higher plants. It is suggested that an environment of structured water may be essential for the functional integrity of Photosystem II in biliprotein-containing algae. PMID:6860312

  17. Photoprotection Conferred by Changes in Photosynthetic Protein Levels and Organization during Dehydration of a Homoiochlorophyllous Resurrection Plant1

    Science.gov (United States)

    Charuvi, Dana; Nevo, Reinat; Shimoni, Eyal; Naveh, Leah; Zia, Ahmad; Adam, Zach; Farrant, Jill M.; Kirchhoff, Helmut; Reich, Ziv

    2015-01-01

    During desiccation, homoiochlorophyllous resurrection plants retain most of their photosynthetic apparatus, allowing them to resume photosynthetic activity quickly upon water availability. These plants rely on various mechanisms to prevent the formation of reactive oxygen species and/or protect their tissues from the damage they inflict. In this work, we addressed the issue of how homoiochlorophyllous resurrection plants deal with the problem of excessive excitation/electron pressures during dehydration using Craterostigma pumilum as a model plant. To investigate the alterations in the supramolecular organization of photosynthetic protein complexes, we examined cryoimmobilized, freeze-fractured leaf tissues using (cryo)scanning electron microscopy. These examinations revealed rearrangements of photosystem II (PSII) complexes, including a lowered density during moderate dehydration, consistent with a lower level of PSII proteins, as shown by biochemical analyses. The latter also showed a considerable decrease in the level of cytochrome f early during dehydration, suggesting that initial regulation of the inhibition of electron transport is achieved via the cytochrome b6f complex. Upon further dehydration, PSII complexes are observed to arrange into rows and semicrystalline arrays, which correlates with the significant accumulation of sucrose and the appearance of inverted hexagonal lipid phases within the membranes. As opposed to PSII and cytochrome f, the light-harvesting antenna complexes of PSII remain stable throughout the course of dehydration. Altogether, these results, along with photosynthetic activity measurements, suggest that the protection of retained photosynthetic components is achieved, at least in part, via the structural rearrangements of PSII and (likely) light-harvesting antenna complexes into a photochemically quenched state. PMID:25713340

  18. Photosynthetic Energy Transduction Publications | Bioenergy | NREL

    Science.gov (United States)

    metabolism, Proc. Nat. Acad. Sci. USA Image of altered membrane morphologies and lipid compositions in dark , partially confer FDX2 the redox potential and catalytic properties of FDX1, Photosynthesis Research Image of photobiological H2 Production: the O2 sensitivity of Hydrogenases, Photosynthesis Research Enhancing photo

  19. Optimization of Adsorptive Immobilization of Alcohol Dehydrogenases

    NARCIS (Netherlands)

    Trivedi, Archana; Heinemann, Matthias; Spiess, Antje C.; Daussmann, Thomas; Büchs, Jochen

    2005-01-01

    In this work, a systematic examination of various parameters of adsorptive immobilization of alcohol dehydrogenases (ADHs) on solid support is performed and the impact of these parameters on immobilization efficiency is studied. Depending on the source of the enzymes, these parameters differently

  20. Plutonium Immobilization Can Loading Equipment Review

    International Nuclear Information System (INIS)

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.

    1998-05-01

    This report lists the operations required to complete the Can Loading steps on the Pu Immobilization Plant Flow Sheets and evaluates the equipment options to complete each operation. This report recommends the most appropriate equipment to support Plutonium Immobilization Can Loading operations

  1. Strong and Reversible Monovalent Supramolecular Protein Immobilization

    NARCIS (Netherlands)

    Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

    2010-01-01

    Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

  2. Drug immobilization of walrus (Odobenus rosmarus)

    Science.gov (United States)

    DeMaster, D.P.; Faro, J.B.; Estes, J.A.; Taggart, James; Zabel, C.

    1981-01-01

    Five out of nine walrus (Odobenus rosmarus) were successfully immobilized at Round Island, Alaska, in May of 1978 by combinations of phencyclidine hydrochloride and acepromazine hydrochloride. A crossbow was an effective delivery technique. Walruses that had recently hauled out were more suitable for immobilization than well-rested animals. Care was taken to prevent walruses from overheating or suffocating.

  3. Effects of different algaecides on the photosynthetic capacity, cell integrity and microcystin-LR release of Microcystis aeruginosa

    International Nuclear Information System (INIS)

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Deng, Yang; Qiao, Junlian; Ou, Huase; Deng, Jing

    2013-01-01

    Bench scale tests were conducted to study the effects of four common algaecides, including copper sulfate, hydrogen peroxide, diuron and ethyl 2-methylacetoacetate (EMA) on the photosynthetic capacity, cell integrity and microcystin-LR (MC-LR) release of Microcystis aeruginosa. The release of potassium (K + ) from cell membrane during algaecide exposure was also analyzed. The three typical photosynthetic parameters, including the effective quantum yield (φ e ), photosynthetic efficiency (α) and maximal electron transport rate (rETR max ), were measured by a pulse amplitude modulated (PAM) fluorometry. Results showed that the photosynthetic capacity was all inhibited by the four algaecides, to different degrees, by limiting the energy capture in photosynthesis, and blocking the electron transfer chain in primary reaction. For example, at high diuron concentration (7.5 mg L −1 ), φ e , α and rETR max decreased from 0.46 to 0.19 (p −2 s −1 /μmol photons m −2 s −1 , and from 160.7 to 0.1 (p −2 s −1 compared with the control group after 96 h of exposure, respectively. Furthermore, the increase of algaecide dose could lead to the cell lysis, as well as release of intracellular MC-LR that enhanced the accumulation of extracellular MC-LR. The order of MC-LR release potential for the four algaecides was CuSO 4 > H 2 O 2 > diuron > EMA. Highlights: • PAM was used to investigate the effects of algaecides on Microcystis aeruginosa. • We estimate the release of potassium (K + ) from cell membrane for cell lysis. • The risk of microcystin-LR release was evaluated after algaecides exposure. • The order of MC-LR release potential was copper sulfate > hydrogen peroxide > diuron > ethyl 2-methylacetoacetate

  4. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gregory Kremer; Dr. David J. Bayless; Dr. Morgan Vis; Dr. Michael Prudich; Dr. Keith Cooksey; Dr. Jeff Muhs

    2001-07-25

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 4/03/2001 through 7/02/2001. Most of the achievements are milestones in our efforts to complete the tasks and subtasks that constitute the project objectives. Note that this version of the quarterly technical report is a revision to add the reports from subcontractors Montana State and Oak Ridge National Laboratories The significant accomplishments for this quarter include: Development of an experimental plan and initiation of experiments to create a calibration curve that correlates algal chlorophyll levels with carbon levels (to simplify future experimental procedures); Completion of debugging of the slug flow reactor system, and development of a plan for testing the pressure drop of the slug flow reactor; Design and development of a new bioreactor screen design which integrates the nutrient delivery drip system and the harvesting system; Development of an experimental setup for testing the new integrated drip system/harvesting system; Completion of model-scale bioreactor tests examining the effects of CO{sub 2} concentration levels and lighting levels on Nostoc 86-3 growth rates; Completion of the construction of a larger model-scale bioreactor to improve and expand testing capabilities and initiation of tests; Substantial progress on construction of a pilot-scale bioreactor; and Preliminary economic analysis of photobioreactor deployment. Plans for next quarter's work are included in the conclusions. A preliminary economic analysis is included as an appendix.

  5. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David J. Bayless; Dr. Morgan Vis; Dr. Gregory Kremer; Dr. Michael Prudich; Dr. Keith Cooksey; Dr. Jeff Muhs

    2001-01-16

    This is the first quarterly report of the project Enhanced Practical Photosynthetic CO{sub 2} Mitigation. The official project start date, 10/02/2000, was delayed until 10/31/2000 due to an intellectual property dispute that was resolved. However, the delay forced a subsequent delay in subcontracting with Montana State University, which then delayed obtaining a sampling permit from Yellowstone National Park. However, even with these delays, the project moved forward with some success. Accomplishments for this quarter include: Culturing of thermophilic organisms from Yellowstone; Testing of mesophilic organisms in extreme CO{sub 2} conditions; Construction of a second test bed for additional testing; Purchase of a total carbon analyzer dedicated to the project; Construction of a lighting container for Oak Ridge National Laboratory optical fiber testing; Modified lighting of existing test box to provide more uniform distribution; Testing of growth surface adhesion and properties; Experimentation on water-jet harvesting techniques; and Literature review underway regarding uses of biomass after harvesting. Plans for next quarter's work and an update on the project's web page are included in the conclusions.

  6. Photosynthetic efficiency of Chlamydomonas reinhardtii in flashing light

    NARCIS (Netherlands)

    Vejrazka, C.; Janssen, M.G.J.; Streefland, M.; Wijffels, R.H.

    2011-01-01

    Efficient light to biomass conversion in photobioreactors is crucial for economically feasible microalgae production processes. It has been suggested that photosynthesis is enhanced in short light path photobioreactors by mixing-induced flashing light regimes. In this study, photosynthetic

  7. Dynamics of photosynthetic activity of cyanobacteria after gut ...

    African Journals Online (AJOL)

    African Journal of Biotechnology ... carp and goldfish, whereas there was a significant stimulation of photosynthetic activity of diatom and green algae following the depressed cyanobacteria during cultivation. The mainly stimulated eukaryotic algae species were Fragilariaceae and Scenedesmus obliquus by microscopy.

  8. Effects of 1-butanol, neomycin and calcium on the photosynthetic ...

    African Journals Online (AJOL)

    ajl yemi

    2011-10-31

    Oct 31, 2011 ... (Shanghai Jierui Bio-Engineering Co., Ltd.) were used in the total. RNA extraction of ..... PC and reverse through calcium removal agent. EGTA indicating .... Photosynthetic characteristics and tolerance to photo- oxidation of ...

  9. Photosynthetic responses of pea plants (Pisum sativum L. cv. Little ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... (O3) have fundamental effects on CO2 exchange by plants. ... produce responses such as reduced photosynthetic rates and earlier senescence .... quality localities treatments and two soil regimes in Riyadh city, KSA. Pn rates.

  10. Photosynthetic and nitrogen fixation capability in several soybean mutant lines

    International Nuclear Information System (INIS)

    Gandanegara, S.; Hendratno, K.

    1987-01-01

    Photosynthetic and nitrogen fixation capability in several soybean mutant lines. A greenhouse experiment has been carried out to study photosynthetic and nitrogen fixation capability of five mutant lines and two soybean varieties. An amount of 330 uCi of 14 CO 2 was fed to the plants including of the non-fixing reference crop (Chippewa non-nodulating isoline). Nitrogen fixation measurements was carried out using 15 N isotope dilution technique according to A-value concept. Results showed that beside variety/mutant lines, plant growth also has important role in photosynthetic and N fixing capability. Better growth and a higher photosynthetic capability in Orba, mutant lines nos. 63 and 65 resulted in a greater amount of N 2 fixed (mg N/plant) than other mutant lines. (author). 12 refs.; 5 figs

  11. Counting viruses and bacteria in photosynthetic microbial mats

    NARCIS (Netherlands)

    Carreira, C; Staal, M.; Middelboe, M.; Brussaard, C.P.D.

    2015-01-01

    Viral abundances in benthic environments are the highest found in aquatic systems. Photosynthetic microbial mats represent benthic environments with high microbial activity and possibly high viral densities, yet viral abundances have not been examined in such systems. Existing extraction procedures

  12. Effect of space mutation on photosynthetic characteristics of soybean varieties

    International Nuclear Information System (INIS)

    Liu Xinlei; Ma Yansong; Luan Xiaoyan; Man Weiqun; Xu Dechun; Meng Lifen; Fu Lixin; Zhao Xiaonan; Liu Qi

    2011-01-01

    In order to elucidate the response of the photosynthetic traits of soybean to space mutation, three soybean varieties (lines) of Heinong 48, Heinong 44 and Ha 2291-Y were carried by artificial satellite in 2006 and the net photosynthetic rate (Pn), stomatal conductance (Cond), intercellular CO 2 concentration (Ci) and stomatal resistance (Rs) from SP 1 to SP 4 generation were determined. The results showed that space mutation affected photosynthesis traits of soybean. The photosynthetic rate of soybean varieties by space mutation occurred different levels of genetic variation and the positive mutation rate were higher. Coefficient of variation among generations were SP 2 > SP 3 > SP 4 > CK. Results suggest that space mutation can effectively create soybean materials with higher photosynthetic rate. (authors)

  13. Carotenoids are essential for the assembly of cyanobacterial photosynthetic complexes

    NARCIS (Netherlands)

    Tóth, T.N.; Chukhutsina, Volha; Domonkos, Ildikó; Knoppová, Jana; Komenda, Josef; Kis, Mihály; Lénárt, Zsófia; Garab, Gyozo; Kovács, László; Gombos, Zoltán; Amerongen, Van Herbert

    2015-01-01

    In photosynthetic organisms, carotenoids (carotenes and xanthophylls) are important for light harvesting, photoprotection and structural stability of a variety of pigment-protein complexes. Here, we investigated the consequences of altered carotenoid composition for the functional organization of

  14. Variability of photosynthetic pigments in the Colombian Pacific ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Picture series of surface chlorophyll,. SST, wind ... photosynthetic pigments during the time of inten- sification of ... calculation of Ekman pumping (We) using finite- differencing to ..... Legeckis R 1986 A satellite time series sea surface tempera-.

  15. Layer-by-layer cell membrane assembly

    Science.gov (United States)

    Matosevic, Sandro; Paegel, Brian M.

    2013-11-01

    Eukaryotic subcellular membrane systems, such as the nuclear envelope or endoplasmic reticulum, present a rich array of architecturally and compositionally complex supramolecular targets that are as yet inaccessible. Here we describe layer-by-layer phospholipid membrane assembly on microfluidic droplets, a route to structures with defined compositional asymmetry and lamellarity. Starting with phospholipid-stabilized water-in-oil droplets trapped in a static droplet array, lipid monolayer deposition proceeds as oil/water-phase boundaries pass over the droplets. Unilamellar vesicles assembled layer-by-layer support functional insertion both of purified and of in situ expressed membrane proteins. Synthesis and chemical probing of asymmetric unilamellar and double-bilayer vesicles demonstrate the programmability of both membrane lamellarity and lipid-leaflet composition during assembly. The immobilized vesicle arrays are a pragmatic experimental platform for biophysical studies of membranes and their associated proteins, particularly complexes that assemble and function in multilamellar contexts in vivo.

  16. Immobilizing affinity proteins to nitrocellulose: a toolbox for paper-based assay developers.

    Science.gov (United States)

    Holstein, Carly A; Chevalier, Aaron; Bennett, Steven; Anderson, Caitlin E; Keniston, Karen; Olsen, Cathryn; Li, Bing; Bales, Brian; Moore, David R; Fu, Elain; Baker, David; Yager, Paul

    2016-02-01

    To enable enhanced paper-based diagnostics with improved detection capabilities, new methods are needed to immobilize affinity reagents to porous substrates, especially for capture molecules other than IgG. To this end, we have developed and characterized three novel methods for immobilizing protein-based affinity reagents to nitrocellulose membranes. We have demonstrated these methods using recombinant affinity proteins for the influenza surface protein hemagglutinin, leveraging the customizability of these recombinant "flu binders" for the design of features for immobilization. The three approaches shown are: (1) covalent attachment of thiolated affinity protein to an epoxide-functionalized nitrocellulose membrane, (2) attachment of biotinylated affinity protein through a nitrocellulose-binding streptavidin anchor protein, and (3) fusion of affinity protein to a novel nitrocellulose-binding anchor protein for direct coupling and immobilization. We also characterized the use of direct adsorption for the flu binders, as a point of comparison and motivation for these novel methods. Finally, we demonstrated that these novel methods can provide improved performance to an influenza hemagglutinin assay, compared to a traditional antibody-based capture system. Taken together, this work advances the toolkit available for the development of next-generation paper-based diagnostics.

  17. 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.

  18. On the photosynthetic potential in the very Early Archean oceans.

    Science.gov (United States)

    Avila, Daile; Cardenas, Rolando; Martin, Osmel

    2013-02-01

    In this work we apply a mathematical model of photosynthesis to quantify the potential for photosynthetic life in the very Early Archean oceans. We assume the presence of oceanic blockers of ultraviolet radiation, specifically ferrous ions. For this scenario, our results suggest a potential for photosynthetic life greater than or similar to that in later eras/eons, such as the Late Archean and the current Phanerozoic eon.

  19. Ultrafast fluorescence of photosynthetic crystals and light-harvesting complexes

    OpenAIRE

    Oort, van, B.F.

    2008-01-01

    This thesis focuses on the study of photosynthetic pigment protein complexes using time resolved fluorescence techniques. Fluorescence spectroscopy often requires attaching fluorescent labels to the proteins under investigation. With photosynthetic proteins this is not necessary, because these proteins contain fluorescent pigments. Each pigment’s fluorescence is influenced by its environment, and thereby may provide information on structure and dynamics of pigment protein complexes in vitro a...

  20. Tree Species with Photosynthetic Stems Have Greater Nighttime Sap Flux

    Directory of Open Access Journals (Sweden)

    Xia Chen

    2018-01-01

    Full Text Available An increasing body of evidence has shown that nighttime sap flux occurs in most plants, but the physiological implications and regulatory mechanism are poorly known. The significance of corticular photosynthesis has received much attention during the last decade, however, the knowledge of the relationship between corticular photosynthesis and nocturnal stem sap flow is limited at present. In this study, we divided seven tree species into two groups according to different photosynthetic capabilities: trees of species with (Castanopsis hystrix, Michelia macclurei, Eucalyptus citriodora, and Eucalyptus grandis × urophylla and without (Castanopsis fissa, Schima superba, and Acacia auriculiformis photosynthetic stems, and the sap flux (Js and chlorophyll fluorescence parameters for these species were measured. One-way ANOVA analysis showed that the Fv/Fm (Maximum photochemical quantum yield of PSII and ΦPSII (effective photochemical quantum yield of PSII values were lower in non-photosynthetic stem species compared to photosynthetic stem species. The linear regression analysis showed that Js,d (daytime sap flux and Js,n (nighttime sap flux of non-photosynthetic stem species was 87.7 and 60.9% of the stem photosynthetic species. Furthermore, for a given daytime transpiration water loss, total nighttime sap flux was higher in species with photosynthetic stems (SlopeSMA = 2.680 than in non-photosynthetic stems species (SlopeSMA = 1.943. These results mean that stem corticular photosynthesis has a possible effect on the nighttime water flow, highlighting the important eco-physiological relationship between nighttime sap flux and corticular photosynthesis.

  1. Tree Species with Photosynthetic Stems Have Greater Nighttime Sap Flux.

    Science.gov (United States)

    Chen, Xia; Gao, Jianguo; Zhao, Ping; McCarthy, Heather R; Zhu, Liwei; Ni, Guangyan; Ouyang, Lei

    2018-01-01

    An increasing body of evidence has shown that nighttime sap flux occurs in most plants, but the physiological implications and regulatory mechanism are poorly known. The significance of corticular photosynthesis has received much attention during the last decade, however, the knowledge of the relationship between corticular photosynthesis and nocturnal stem sap flow is limited at present. In this study, we divided seven tree species into two groups according to different photosynthetic capabilities: trees of species with ( Castanopsis hystrix, Michelia macclurei, Eucalyptus citriodora , and Eucalyptus grandis × urophylla ) and without ( Castanopsis fissa, Schima superba , and Acacia auriculiformis ) photosynthetic stems, and the sap flux ( J s ) and chlorophyll fluorescence parameters for these species were measured. One-way ANOVA analysis showed that the F v / F m (Maximum photochemical quantum yield of PSII) and Φ PSII (effective photochemical quantum yield of PSII) values were lower in non-photosynthetic stem species compared to photosynthetic stem species. The linear regression analysis showed that J s,d (daytime sap flux) and J s,n (nighttime sap flux) of non-photosynthetic stem species was 87.7 and 60.9% of the stem photosynthetic species. Furthermore, for a given daytime transpiration water loss, total nighttime sap flux was higher in species with photosynthetic stems (Slope SMA = 2.680) than in non-photosynthetic stems species (Slope SMA = 1.943). These results mean that stem corticular photosynthesis has a possible effect on the nighttime water flow, highlighting the important eco-physiological relationship between nighttime sap flux and corticular photosynthesis.

  2. Tree Species with Photosynthetic Stems Have Greater Nighttime Sap Flux

    Science.gov (United States)

    Chen, Xia; Gao, Jianguo; Zhao, Ping; McCarthy, Heather R.; Zhu, Liwei; Ni, Guangyan; Ouyang, Lei

    2018-01-01

    An increasing body of evidence has shown that nighttime sap flux occurs in most plants, but the physiological implications and regulatory mechanism are poorly known. The significance of corticular photosynthesis has received much attention during the last decade, however, the knowledge of the relationship between corticular photosynthesis and nocturnal stem sap flow is limited at present. In this study, we divided seven tree species into two groups according to different photosynthetic capabilities: trees of species with (Castanopsis hystrix, Michelia macclurei, Eucalyptus citriodora, and Eucalyptus grandis × urophylla) and without (Castanopsis fissa, Schima superba, and Acacia auriculiformis) photosynthetic stems, and the sap flux (Js) and chlorophyll fluorescence parameters for these species were measured. One-way ANOVA analysis showed that the Fv/Fm (Maximum photochemical quantum yield of PSII) and ΦPSII (effective photochemical quantum yield of PSII) values were lower in non-photosynthetic stem species compared to photosynthetic stem species. The linear regression analysis showed that Js,d (daytime sap flux) and Js,n (nighttime sap flux) of non-photosynthetic stem species was 87.7 and 60.9% of the stem photosynthetic species. Furthermore, for a given daytime transpiration water loss, total nighttime sap flux was higher in species with photosynthetic stems (SlopeSMA = 2.680) than in non-photosynthetic stems species (SlopeSMA = 1.943). These results mean that stem corticular photosynthesis has a possible effect on the nighttime water flow, highlighting the important eco-physiological relationship between nighttime sap flux and corticular photosynthesis. PMID:29416547

  3. Production of bioplastics and hydrogen gas by photosynthetic microorganisms

    Science.gov (United States)

    Yasuo, Asada; Masato, Miyake; Jun, Miyake

    1998-03-01

    Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium, Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilic Synechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes from Alcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted. In vitro and in vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture of Rhodobacter and Clostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium, Rhodobacter sphaeroides RV. A mutant acquired by

  4. Rice Photosynthetic Productivity and PSII Photochemistry under Nonflooded Irrigation

    Directory of Open Access Journals (Sweden)

    Haibing He

    2014-01-01

    Full Text Available Nonflooded irrigation is an important water-saving rice cultivation technology, but little is known on its photosynthetic mechanism. The aims of this work were to investigate photosynthetic characteristics of rice during grain filling stage under three nonflooded irrigation treatments: furrow irrigation with plastic mulching (FIM, furrow irrigation with nonmulching (FIN, and drip irrigation with plastic mulching (DI. Compared with the conventional flooding (CF treatment, those grown in the nonflooded irrigation treatments showed lower net photosynthetic rate (PN, lower maximum quantum yield (Fv/Fm, and lower effective quantum yield of PSII photochemistry (ΦPSII. And the poor photosynthetic characteristics in the nonflooded irrigation treatments were mainly attributed to the low total nitrogen content (TNC. Under non-flooded irrigation, the PN, Fv/Fm, and ΦPSII significantly decreased with a reduction in the soil water potential, but these parameters were rapidly recovered in the DI and FIM treatments when supplementary irrigation was applied. Moreover, The DI treatment always had higher photosynthetic productivity than the FIM and FIN treatments. Grain yield, matter translocation, and dry matter post-anthesis (DMPA were the highest in the CF treatment, followed by the DI, FIM, and FIN treatments in turn. In conclusion, increasing nitrogen content in leaf of rice plants could be a key factor to improve photosynthetic capacity in nonflooded irrigation.

  5. ZirfonR-composite membranes: properties and applications

    International Nuclear Information System (INIS)

    Leysen, R.; Doyen, W.; Adriansen, W.; Vermeiren, Ph.

    1993-01-01

    In this report, the fabrication and the applications of a new type of composite membrane, the zirconium-oxide-polysulphone membrane (registered trade mark name: Zirfon), are described. The investigated Zirfon membranes are fabricated by the film casting technique and are composed of zirconium oxide powder and a polymeric binder, polysulphone. Zirfon membranes have been developed first for use as separators in electrochemical applications (e.g. alkaline water electrolysis and alkaline fuel cells). Besides their applications in electrochemical systems, Zirfon membranes have been tested as separating membranes for several ultrafiltration purposes. The most recent application of Zirfon membranes is their use for the removal of heavy metals in waste streams by means of incorporated bacteria. In this application, micro-organisms are immobilized on the porous structure of the membrane. Potential future applications are in the field of energy production (fuel cells) and the treatment of non-nuclear or nuclear waste water. (A.S.)

  6. Thermoluminescence as a complementary technique for the toxicological evaluation of chemicals in photosynthetic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Guillermo, E-mail: grepkuh@upo.es [Departamento de Biología Molecular e Ingeniería Bioquímica, Área de Toxicología, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Seville (Spain); Zurita, Jorge L. [Departamento de Biología Molecular e Ingeniería Bioquímica, Área de Toxicología, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Seville (Spain); Roncel, Mercedes; Ortega, José M. [Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville (Spain)

    2015-01-15

    Highlights: • There are very few toxicological applications of thermoluminescence. • It is a luminescence emission induced by heating the sample in the dark. • It is useful for study the photosystem II function and the level of lipid peroxidation. - Abstract: Thermoluminescence is a simple technique very useful for studying electron transfer reactions on photosystem II (standard thermoluminescence) or the level of lipid peroxidation in membranes (high temperature thermoluminescence) in photosynthetic organisms. Both techniques were used to investigate the effects produced on Chlorella vulgaris cells by six compounds: the chemical intermediates bromobenzene and diethanolamine, the antioxidant propyl gallate, the semiconductor indium nitrate, the pesticide sodium monofluoroacetate and the antimalarial drug chloroquine. Electron transfer activity of the photosystem II significantly decreased after the exposure of Chlorella cells to all the six chemicals used. Lipid peroxidation was slightly decreased by the antioxidant propyl gallate, not changed by indium nitrate and very potently stimulated by diethanolamine, chloroquine, sodium monofluoroacetate and bromobenzene. For five of the chemicals studied (not bromobenzene) there is a very good correlation between the cytotoxic effects in Chlorella cells measured by the algal growth inhibition test, and the inhibition of photosystem II activity. The results suggest that one very important effect of these chemicals in Chlorella cells is the inhibition of photosynthetic metabolism by the blocking of photosystem II functionality. In the case of sodium monofluoroacetate, diethanolamine and chloroquine this inhibition seems to be related with the induction of high level of lipid peroxidation in cells that may alter the stability of photosystem II. The results obtained by both techniques supply information that can be used as a supplement to the growth inhibition test and allows a more complete assessment of the effects of

  7. Thermoluminescence as a complementary technique for the toxicological evaluation of chemicals in photosynthetic organisms

    International Nuclear Information System (INIS)

    Repetto, Guillermo; Zurita, Jorge L.; Roncel, Mercedes; Ortega, José M.

    2015-01-01

    Highlights: • There are very few toxicological applications of thermoluminescence. • It is a luminescence emission induced by heating the sample in the dark. • It is useful for study the photosystem II function and the level of lipid peroxidation. - Abstract: Thermoluminescence is a simple technique very useful for studying electron transfer reactions on photosystem II (standard thermoluminescence) or the level of lipid peroxidation in membranes (high temperature thermoluminescence) in photosynthetic organisms. Both techniques were used to investigate the effects produced on Chlorella vulgaris cells by six compounds: the chemical intermediates bromobenzene and diethanolamine, the antioxidant propyl gallate, the semiconductor indium nitrate, the pesticide sodium monofluoroacetate and the antimalarial drug chloroquine. Electron transfer activity of the photosystem II significantly decreased after the exposure of Chlorella cells to all the six chemicals used. Lipid peroxidation was slightly decreased by the antioxidant propyl gallate, not changed by indium nitrate and very potently stimulated by diethanolamine, chloroquine, sodium monofluoroacetate and bromobenzene. For five of the chemicals studied (not bromobenzene) there is a very good correlation between the cytotoxic effects in Chlorella cells measured by the algal growth inhibition test, and the inhibition of photosystem II activity. The results suggest that one very important effect of these chemicals in Chlorella cells is the inhibition of photosynthetic metabolism by the blocking of photosystem II functionality. In the case of sodium monofluoroacetate, diethanolamine and chloroquine this inhibition seems to be related with the induction of high level of lipid peroxidation in cells that may alter the stability of photosystem II. The results obtained by both techniques supply information that can be used as a supplement to the growth inhibition test and allows a more complete assessment of the effects of

  8. Plutonium Immobilization Can Loading Concepts

    International Nuclear Information System (INIS)

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

    1998-05-01

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item

  9. Immobilization of organic liquid wastes

    International Nuclear Information System (INIS)

    Greenhalgh, W.O.

    1985-01-01

    This report describes a portland cement immobilization process for the disposal treatment of radioactive organic liquid wastes which would be generated in a a FFTF fuels reprocessing line. An incineration system already on-hand was determined to be too costly to operate for the 100 to 400 gallons per year organic liquid. Organic test liquids were dispersed into an aqueous phosphate liquid using an emulsifier. A total of 109 gallons of potential and radioactive aqueous immiscible organic liquid wastes from Hanford 300 Area operations were solidified with portland cement and disposed of as solid waste during a 3-month test program with in-drum mixers. Waste packing efficiencies varied from 32 to 40% and included pump oils, mineral spirits, and TBP-NPH type solvents

  10. Uranium Immobilization in Wetland Soils

    Science.gov (United States)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    stronger for the mesocosms with the higher Fe(II) load. Analysis via XANES showed that a fraction (up to ~1/3) of uranium was reduced to U(IV), for mesocosms operated under low iron loading, indicating that iron cycling in the rhizosphere also results in uranium reduction and immobilization. For mesocosms operating under the higher iron loading, the fraction of uranium immobilized as U(IV) was much lower, indicating that uranium co-precipitation with iron might have been the dominant immobilization process. In parallel to these mesocosm experiments, dialysis samplers have been deployed at the Savannah River National Laboratory near a creek with uranium contamination, to determine dissolved species, including Fe(II) and U(VI) in these wetland soils and their seasonal variability. The results show that there is a strong seasonal variability in dissolved iron and uranium, indicating a strong immobilization during the growing season, which is consistent with the mesocosm experimental results that the rhizosphere iron and uranium cycling are closely linked.

  11. Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.

    Science.gov (United States)

    Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

    2013-02-01

    Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David J. Bayless; Dr. Morgan Vis; Dr. Gregory Kremer; Dr. Michael Prudich; Dr. Keith Cooksey; Dr. Jeff Muhs

    2001-04-16

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 1/03/2001 through 4/02/2001. Many of the activities and accomplishments are continuations of work initiated and reported in last quarter's status report. Major activities and accomplishments for this quarter include: Three sites in Yellowstone National Park have been identified that may contain suitable organisms for use in a bioreactor; Full-scale culturing of one thermophilic organism from Yellowstone has progressed to the point that there is a sufficient quantity to test this organism in the model-scale bioreactor; The effects of the additive monoethanolamine on the growth of one thermophilic organism from Yellowstone has been tested; Testing of growth surface adhesion and properties is continuing; Construction of a larger model-scale bioreactor to improve and expand testing capabilities is completed and the facility is undergoing proof tests; Model-scale bioreactor tests examining the effects of CO{sub 2} concentration levels and lighting levels on organism growth rates are continuing; Alternative fiber optic based deep-penetration light delivery systems for use in the pilot-scale bioreactor have been designed, constructed and tested; An existing slug flow reactor system has been modified for use in this project, and a proof-of-concept test plan has been developed for the slug flow reactor; Research and testing of water-jet harvesting techniques is continuing, and a harvesting system has been designed for use in the model-scale bioreactor; and The investigation of comparative digital image analysis as a means for determining the ''density'' of algae on a growth surface is continuing Plans for next quarter's work and an update on the project's web page are included in the conclusions.

  13. Radioactive seed immobilization techniques for interstitial brachytherapy

    International Nuclear Information System (INIS)

    Yan, K.; Podder, T.; Buzurovic, I.; Hu, Y.; Dicker, A.; Valicenti, R.; Yu, Y.; Messing, E.; Rubens, D.; Sarkar, N.; Ng, W.

    2008-01-01

    In prostate brachytherapy, seeds can detach from their deposited sites and move locally in the pelvis or migrate to distant sites including the pulmonary and cardiac regions. Undesirable consequences of seed migration include inadequate dose coverage of the prostate and tissue irradiation effects at the site of migration. Thus, it is clinically important to develop seed immobilization techniques. We first analyze the possible causes for seed movement, and propose three potential techniques for seed immobilization: (1) surgical glue, (2) laser coagulation and (3) diathermy coagulation. The feasibility of each method is explored. Experiments were carried out using fresh bovine livers to investigate the efficacy of seed immobilization using surgical glue. Results have shown that the surgical glue can effectively immobilize the seeds. Evaluation of the radiation dose distribution revealed that the non-immobilized seed movement would change the planned isodose distribution considerably; while by using surgical glue method to immobilize the seeds, the changes were negligible. Prostate brachytherapy seed immobilization is necessary and three alternative mechanisms are promising for addressing this issue. Experiments for exploring the efficacy of the other two proposed methods are ongoing. Devices compatible with the brachytherapy procedure will be designed in future. (orig.)

  14. Membrane bioreactors for enzymatic hydrolysis of lactose; Idrolisi enzimatica del lattosio con bioreattori a membrana

    Energy Technology Data Exchange (ETDEWEB)

    Pizzichini, M; Pilloton, R [ENEA, Casaccia (Italy). Area Energia e Innovazione; Pontecorvo, M; Mignogna, G; Fortunato, A; Beone, F

    1993-03-01

    Bioreactor systems obtained by cell or enzyme immobilization offer many advantages compared with native enzyme, intact cell systems or other biocatalysts. Thus, many attempts have been made to design and use new types of bioreactor systems in order to improve performance, enhance productivity and reduce environmental impacts. Membrane bioreactors, obtained by physical immobilization of biocatalysts, in polymeric membrane support, offer such practical advantages as: a continuous separation and transformation process with low product inhibition and suitable hydraulic configuration (backflushing recycling, ultrafiltrating). Specific membrane modules (Amicon VitaFiber), for bioreactor applications are being commercialized. Beta-galctosidase enzyme has successfully been immobilized in a hollow fiber and in ceramic modules to hydrolyze lactose in waste whey. This technical report presents the general properties and performances (permeability, washing procedures, hydraulic configurations, physical and chemical properties) of both, polymeric and ceramic supports, enzyme kinetics, physical and covalent immobilization, mathematical model of the bioreactor and on-line process monitoring.

  15. Modelling excitonic energy transfer in the photosynthetic unit of purple bacteria

    International Nuclear Information System (INIS)

    Linnanto, J.M.; Korppi-Tommola, J.E.I.

    2009-01-01

    Molecular mechanics and quantum chemical configuration interaction calculations in combination with exciton theory were used to predict vibronic energies and eigenstates of light harvesting antennae and the reaction centre and to evaluate excitation energy transfer rates in the photosynthetic unit of purple bacteria. Excitation energy transfer rates were calculated by using the transition matrix formalism and exciton basis sets of the interacting antenna systems. Energy transfer rates of 600-800 fs from B800 ring to B850 ring in the LH2 antenna, 3-10 ps from LH2 to LH2 antenna, 2-8 ps from LH2 to LH1 antenna and finally 30-70 ps from LH1 to the reaction centre were obtained. Dependencies of energy transfer rates on lateral and vertical inter-complex distances were determined. The results indicate that a fair amount of spatial heterogeneity of antenna complexes in the photosynthetic membrane is tolerated without much loss in excitation energy transfer efficiency

  16. Modelling excitonic energy transfer in the photosynthetic unit of purple bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Linnanto, J.M. [Department of Chemistry, P.O. Box 35, FIN-40014 University of Jyvaeskylae, Jyvaeskylae (Finland)], E-mail: juha.m.linnanto@jyu.fi; Korppi-Tommola, J.E.I. [Department of Chemistry, P.O. Box 35, FIN-40014 University of Jyvaeskylae, Jyvaeskylae (Finland)

    2009-02-23

    Molecular mechanics and quantum chemical configuration interaction calculations in combination with exciton theory were used to predict vibronic energies and eigenstates of light harvesting antennae and the reaction centre and to evaluate excitation energy transfer rates in the photosynthetic unit of purple bacteria. Excitation energy transfer rates were calculated by using the transition matrix formalism and exciton basis sets of the interacting antenna systems. Energy transfer rates of 600-800 fs from B800 ring to B850 ring in the LH2 antenna, 3-10 ps from LH2 to LH2 antenna, 2-8 ps from LH2 to LH1 antenna and finally 30-70 ps from LH1 to the reaction centre were obtained. Dependencies of energy transfer rates on lateral and vertical inter-complex distances were determined. The results indicate that a fair amount of spatial heterogeneity of antenna complexes in the photosynthetic membrane is tolerated without much loss in excitation energy transfer efficiency.

  17. Surface cell immobilization within perfluoroalkoxy microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

    2014-11-30

    Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor{sup ®} and Topas{sup ®}.

  18. Immobilization of cellulase using porous polymer matrix

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1984-01-01

    A new method is discussed for the immobilization of cellulase using porous polymer matrices, which were obtained by radiation polymerization of hydrophilic monomers. In this method, the immobilized enzyme matrix was prepared by enzyme absorbtion in the porous polymer matrix and drying treatment. The enzyme activity of the immobilized enzyme matrix varied with monomer concentration, cooling rate of the monomer solution, and hydrophilicity of the polymer matrix, takinn the change of the nature of the porous structure in the polymer matrix. The leakage of the enzymes from the polymer matrix was not observed in the repeated batch enzyme reactions

  19. Immobilization of Peroxidase onto Magnetite Modified Polyaniline

    Directory of Open Access Journals (Sweden)

    Eduardo Fernandes Barbosa

    2012-01-01

    Full Text Available The present study describes the immobilization of horseradish peroxidase (HRP on magnetite-modified polyaniline (PANImG activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25% obtained for PANIG with an efficiency of 100% (active protein. The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity.

  20. Removal of radioactivity and safe vegetables cultivation from highly radioactivity polluted soil in Fukushima using photosynthetic bacteria

    International Nuclear Information System (INIS)

    Sasaki, Kei; Okagawa, Masakazu; Takeno, Kenji; Shinkawa, Hidenori; Sasaki, Ken

    2015-01-01

    The soil pollution caused by radioactive substances released from the accident of TEPCO Fukushima Daiichi Nuclear Power Station has been still serious interference against agricultural reconstruction. This study used the soil contaminated with high radioactivity (13,602∼87,181 Bq/kg) in Namie Town, Fukushima Prefecture, and performed decontamination using photosynthetic bacteria in a simple outdoor practical test using a 60 L container. Using the soil after decontamination, the authors cultivated vegetables such as komatsuna (Japanese mustard spinach), and bok choy, the results of which are reported. As photosynthetic bacteria, Rhodobacter shaerodes SSI species was used. This paper describes the cultivation method of bacteria, preparation method of immobilization grain, decontamination method, and cultivation method of vegetables. As a result of the experiment, the decontamination efficient of the soil was between 59.5 to 73.3%, and cultured vegetables passed the edible reference value (edible criteria for infants: 50 Bq/kg FW), which was the success of the experiment. (A.O.)

  1. A novel photosynthetic strategy for adaptation to low-iron aquatic environments

    Science.gov (United States)

    Chauhan, D.; Folea, I.M.; Jolley, C.C.; Kouril, R.; Lubner, C.E.; Lin, S.; Kolber, D.; Wolfe-Simon, Felisa; Golbeck, J.H.; Boekema, E.J.; Fromme, P.

    2011-01-01

    Iron (Fe) availability is a major limiting factor for primary production in aquatic environments. Cyanobacteria respond to Fe deficiency by derepressing the isiAB operon, which encodes the antenna protein IsiA and flavodoxin. At nanomolar Fe concentrations, a PSI-IsiA supercomplex forms, comprising a PSI trimer encircled by two complete IsiA rings. This PSI-IsiA supercomplex is the largest photosynthetic membrane protein complex yet isolated. This study presents a detailed characterization of this complex using transmission electron microscopy and ultrafast fluorescence spectroscopy. Excitation trapping and electron transfer are highly efficient, allowing cyanobacteria to avoid oxidative stress. This mechanism may be a major factor used by cyanobacteria to successfully adapt to modern low-Fe environments. ?? 2010 American Chemical Society.

  2. Preparation and characterization of immobilized lipase on magnetic hydrophobic microspheres

    DEFF Research Database (Denmark)

    Guo, Zheng; Bai, Shu; Sun, Yan

    2003-01-01

    H for the immobilized CCL were determined. Activity amelioration of the immobilized CCL for the hydrolysis of olive oil was observed, indicating an interfacial activation of the enzyme after immobilization. Moreover, the immobilized CCL showed enhanced thermal stability and good durability in the repeated use after...

  3. Functions of tocopherols in the cells of plants and other photosynthetic organisms.

    Science.gov (United States)

    Mokrosnop, V M

    2014-01-01

    Tocopherol synthesis has only been observed in photosynthetic organisms (plants, algae and some cyanobacteria). Tocopherol is synthesized in the inner membrane of chloroplasts and distributed between chloroplast membranes, thylakoids and plastoglobules. Physiological significance of tocopherols for human and animal is well-studied, but relatively little is known about their function in plant organisms. Among the best characterized functions oftocopherols in cells is their ability to scavenge and quench reactive oxygen species and fat-soluble by-products of oxidative stress. There are the data on the participation of different mechanisms of α-tocopherol action in protecting photosystem II (PS II) from photoinhibition both by deactivation of singlet oxygen produced by PSII and by reduction of proton permeability of thylakoid membranes, leading to acidification of lumen under high light conditions and activation of violaxanthin de-epoxidase. Additional biological activity of tocopherols, independent of its antioxidant functions have been demonstrated. Basic mechanisms for these effects are connected with the modulation of signal transduction pathways by specific tocopherols and, in some instances, by transcriptional activation of gene expression.

  4. Optimizing Immobilized Enzyme Performance in Cell-Free Environments to Produce Liquid Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Belfort, Georges [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemical and Biological Engineering; Grimaldi, Joseph J. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemical and Biological Engineering

    2015-01-27

    Limitations on biofuel production using cell culture (Escherichia coli, Clostridium, Saccharomyces cerevisiae, brown microalgae, blue-green algae and others) include low product (alcohol) concentrations (≤0.2 vol%) due to feedback inhibition, instability of cells, and lack of economical product recovery processes. To overcome these challenges, an alternate simplified biofuel production scheme was tested based on a cell-free immobilized enzyme system. Using this cell free system, we were able to obtain about 2.6 times higher concentrations of iso-butanol using our non-optimized system as compared with live cell systems. This process involved two steps: (i) converts acid to aldehyde using keto-acid decarboxylase (KdcA), and (ii) produces alcohol from aldehyde using alcohol dehydrogenase (ADH) with a cofactor (NADH) conversion from inexpensive formate using a third enzyme, formate dehydrogenase (FDH). To increase stability and conversion efficiency with easy separations, the first two enzymes were immobilized onto methacrylate resin. Fusion proteins of labile KdcA (fKdcA) were expressed to stabilize the covalently immobilized KdcA. Covalently immobilized ADH exhibited long-term stability and efficient conversion of aldehyde to alcohol over multiple batch cycles without fusions. High conversion rates and low protein leaching were achieved by covalent immobilization of enzymes on methacrylate resin. The complete reaction scheme was demonstrated by immobilizing both ADH and fKdcA and using FDH free in solution. The new system without in situ removal of isobutanol achieved a 55% conversion of ketoisovaleric acid to isobutanol at a concentration of 0.5 % (v/v). Further increases in titer will require continuous removal of the isobutanol using our novel brush membrane system that exhibits a 1.5 fold increase in the separation factor of isobutanol from water versus that obtained for commercial silicone rubber membranes. These bio-inspired brush membranes are based on the

  5. Peripheral Protein Unfolding Drives Membrane Bending.

    Science.gov (United States)

    Siaw, Hew Ming Helen; Raghunath, Gokul; Dyer, R Brian

    2018-06-20

    Dynamic modulation of lipid membrane curvature can be achieved by a number of peripheral protein binding mechanisms such as hy-drophobic insertion of amphipathic helices and membrane scaffolding. Recently, an alternative mechanism was proposed in which crowding of peripherally bound proteins induces membrane curvature through steric pressure generated by lateral collisions. This effect was enhanced using intrinsically disordered proteins that possess high hydrodynamic radii, prompting us to explore whether membrane bending can be triggered by the folding-unfolding transition of surface-bound proteins. We utilized histidine-tagged human serum albumin bound to Ni-NTA-DGS containing liposomes as our model system to test this hypothesis. We found that reduction of the disulfide bonds in the protein resulted in unfolding of HSA, which subsequently led to membrane tubule formation. The frequency of tubule formation was found to be significantly higher when the proteins were unfolded while being localized to a phase-separated domain as opposed to randomly distributed in fluid phase liposomes, indicating that the steric pressure generated from protein unfolding is directly responsible for membrane deformation. Our results are critical for the design of peripheral membrane protein-immobilization strategies and open new avenues for exploring mechanisms of membrane bending driven by conformational changes of peripheral membrane proteins.

  6. Photosynthetic Characteristics and Chloroplast Ultrastructure of Summer Maize Response to Different Nitrogen Supplies.

    Science.gov (United States)

    Liu, Zheng; Gao, Jia; Gao, Fei; Liu, Peng; Zhao, Bin; Zhang, Jiwang

    2018-01-01

    Maize ( Zea mays L.) is the important crop over the world. Nitrogen (N) as necessary element affects photosynthetic characteristics and grain yield of summer maize. In this study, N0 (0 kg N ha -1 ), N1 (129 kg N ha -1 ), N2 (185 kg N ha -1 ), and N3 (300 kg N ha -1 ) was conducted using hybrid 'ZhengDan958' at Dawenkou research field (36°11'N, 117°06'E, 178 m altitude) in the North China Plain to explore the effects of N rate on photosynthetic characteristics and chloroplast ultrastructure. Gas exchange parameters, chlorophyll fluorescence parameters, leaf area index (LAI), chlorophyll SPAD value, chloroplast ultrastructure, dry matter weight and grain yield were measured. At physiological maturity stage, dry matter weight and grain yield of N2 increased by 33-52% ( P ≤ 0.05) and 6-32% ( P ≤ 0.05), respectively, compared with other treatments. During the growing from silking (R1) to milk (R3) stage, LAI of N0 and N1 were 35-38% ( P ≤ 0.05) and 9-23% ( P ≤ 0.05) less than that of N2, respectively. Chlorophyll SPAD value of N0 and N1 were 13-22% ( P ≤ 0.05) and 5-11% ( P ≤ 0.05) lower than that of N2. There was no significant difference in LAI and chlorophyll SPAD value between N2 and N3 during the period from R1 to R3 ( P > 0.05). The net photosynthetic rate ( P n ), maximal quantum efficiency of PSII ( F v / F m ) and quantum efficiency of PSII (Φ PSII ) were higher with the increase of N rate up to N2 ( P ≤ 0.05), and those of N3 were significantly less than N2 ( P ≤ 0.05). In compared with N2, the chloroplast configuration of N0 and N1 became elliptical, almost circular or irregular. The membrane of chloroplast and thylakoid resolved with growing stage, and the number of chloroplast per cell and lamellae per grana decreased under N0 and N1 treatment ( P ≤ 0.05). Under N0 and N1 treatments, summer maize had more negative photosynthetic characteristics. The more number of osmium granule and vesicle and the larger gap between lamellae were

  7. Photosynthetic Characteristics and Chloroplast Ultrastructure of Summer Maize Response to Different Nitrogen Supplies

    Directory of Open Access Journals (Sweden)

    Zheng Liu

    2018-05-01

    Full Text Available Maize (Zea mays L. is the important crop over the world. Nitrogen (N as necessary element affects photosynthetic characteristics and grain yield of summer maize. In this study, N0 (0 kg N ha-1, N1 (129 kg N ha-1, N2 (185 kg N ha-1, and N3 (300 kg N ha-1 was conducted using hybrid ‘ZhengDan958’ at Dawenkou research field (36°11′N, 117°06′E, 178 m altitude in the North China Plain to explore the effects of N rate on photosynthetic characteristics and chloroplast ultrastructure. Gas exchange parameters, chlorophyll fluorescence parameters, leaf area index (LAI, chlorophyll SPAD value, chloroplast ultrastructure, dry matter weight and grain yield were measured. At physiological maturity stage, dry matter weight and grain yield of N2 increased by 33–52% (P ≤ 0.05 and 6–32% (P ≤ 0.05, respectively, compared with other treatments. During the growing from silking (R1 to milk (R3 stage, LAI of N0 and N1 were 35–38% (P ≤ 0.05 and 9–23% (P ≤ 0.05 less than that of N2, respectively. Chlorophyll SPAD value of N0 and N1 were 13–22% (P ≤ 0.05 and 5–11% (P ≤ 0.05 lower than that of N2. There was no significant difference in LAI and chlorophyll SPAD value between N2 and N3 during the period from R1 to R3 (P > 0.05. The net photosynthetic rate (Pn, maximal quantum efficiency of PSII (Fv/Fm and quantum efficiency of PSII (ΦPSII were higher with the increase of N rate up to N2 (P ≤ 0.05, and those of N3 were significantly less than N2 (P ≤ 0.05. In compared with N2, the chloroplast configuration of N0 and N1 became elliptical, almost circular or irregular. The membrane of chloroplast and thylakoid resolved with growing stage, and the number of chloroplast per cell and lamellae per grana decreased under N0 and N1 treatment (P ≤ 0.05. Under N0 and N1 treatments, summer maize had more negative photosynthetic characteristics. The more number of osmium granule and vesicle and the larger gap between lamellae were shown in N3

  8. Carotenoid Photoprotection in Artificial Photosynthetic Antennas

    Energy Technology Data Exchange (ETDEWEB)

    Kloz, Miroslav [VU Univ., Amsterdam (Netherlands); Pillai, Smitha [Arizona State Univ., Tempe, AZ (United States); Kodis, Gerdenis [Arizona State Univ., Tempe, AZ (United States); Gust, Devens [Arizona State Univ., Tempe, AZ (United States); Moore, Thomas A. [Arizona State Univ., Tempe, AZ (United States); Moore, Ana L. [Arizona State Univ., Tempe, AZ (United States); van Grondelle, Rienk [VU Univ., Amsterdam (Netherlands); Kennis, John T. M. [VU Univ., Amsterdam (Netherlands)

    2011-04-14

    . These synthetic systems are providing a deeper understanding of structural and environmental effects on the interactions between carotenoids and tetrapyrroles and thereby better defining their role in controlling natural photosynthetic systems.

  9. Engineering cholesterol-based fibers for antibody immobilization and cell capture

    Science.gov (United States)

    Cohn, Celine

    In 2015, the United States is expected to have nearly 600,000 deaths attributed to cancer. Of these 600,000 deaths, 90% will be a direct result of cancer metastasis, the spread of cancer throughout the body. During cancer metastasis, circulating tumor cells (CTCs) are shed from primary tumors and migrate through bodily fluids, establishing secondary cancer sites. As cancer metastasis is incredibly lethal, there is a growing emphasis on developing "liquid biopsies" that can screen peripheral blood, search for and identify CTCs. One popular method for capturing CTCs is the use of a detection platform with antibodies specifically suited to recognize and capture cancer cells. These antibodies are immobilized onto the platform and can then bind and capture cells of interest. However, current means to immobilize antibodies often leave them with drastically reduced function. The antibodies are left poorly suited for cell capture, resulting in low cell capture efficiencies. This body of work investigates the use of lipid-based fibers to immobilize proteins in a way that retains protein function, ultimately leading to increased cell capture efficiencies. The resulting increased efficiencies are thought to arise from the retained three-dimensional structure of the protein as well as having a complete coating of the material surface with antibodies that are capable of interacting with their antigens. It is possible to electrospin cholesterol-based fibers that are similar in design to the natural cell membrane, providing proteins a more natural setting during immobilization. Such fibers have been produced from cholesterol-based cholesteryl succinyl silane (CSS). These fibers have previously illustrated a keen aptitude for retaining protein function and increasing cell capture. Herein the work focuses on three key concepts. First, a model is developed to understand the immobilization mechanism used by electrospun CSS fibers. The antibody immobilization and cell capturing

  10. Antimicrobial activity of immobilized lactoferrin and lactoferricin.

    Science.gov (United States)

    Chen, Renxun; Cole, Nerida; Dutta, Debarun; Kumar, Naresh; Willcox, Mark D P

    2017-11-01

    Lactoferrin and lactoferricin were immobilized on glass surfaces via two linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The antimicrobial activity of the surfaces was determined using Pseudomonas aeruginosa and Staphylococcus aureus strains by fluorescence microscopy. Lactoferrin and lactoferricin immobilization was confirmed by XPS showing significant increases (p lactoferricin immobilized on glass significantly (p lactoferricin were successfully immobilized on glass surfaces and showed promising antimicrobial activity against pathogenic bacteria. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2612-2617, 2017. © 2016 Wiley Periodicals, Inc.

  11. Immobilization of Rocky Flats Graphite Fines Residue

    International Nuclear Information System (INIS)

    Rudisill, T.S.

    1999-01-01

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report

  12. Immobilization and characterization of inulinase from Ulocladium ...

    Indian Academy of Sciences (India)

    2014-10-20

    Oct 20, 2014 ... The enzyme had optimum pH at 5.6 for free and immobilized U. atrum inulinase on polyester ... ceutical industry because of their beneficial effects in ..... Hanover LWJ 1993 Manufacturing, composing and applications of.

  13. Plutonium Immobilization Bagless Transfer Can Size Evaluation

    International Nuclear Information System (INIS)

    Kriikku, E.; Stokes, M.; Rogers, L.; Ward, C.

    1998-02-01

    This report identifies and documents the most appropriate bagless transfer can size to support Plutonium Immobilization Can Loading operations. Also, this report considers can diameter, can wall thickness, and can length

  14. Modeling intrinsic kinetics in immobilized photocatalytic microreactors

    NARCIS (Netherlands)

    Visan, Aura; Rafieian Boroujeni, Damon; Ogieglo, Wojciech; Lammertink, Rob G.H.

    2014-01-01

    The article presents a simple model for immobilized photocatalytic microreactors following a first order reaction rate with either light independency or light dependency described by photon absorption carrier generation semiconductor physics. Experimental data obtained for various residence times,

  15. A simplified technique for nasoendotracheal tube immobilization.

    OpenAIRE

    Berardo, N.; Leban, S. G.; Williams, F. A.

    1989-01-01

    A simplified technique for immobilization of a nasoendotracheal tube is described in which a wide strap of open cell, hypoallergenic, foam-backed fabric is secured to the patient's head with a Velcro fastener.

  16. Climate controls photosynthetic capacity more than leaf nitrogen contents

    Science.gov (United States)

    Ali, A. A.; Xu, C.; McDowell, N. G.

    2013-12-01

    Global vegetation models continue to lack the ability to make reliable predictions because the photosynthetic capacity varies a lot with growth conditions, season and among species. It is likely that vegetation models link photosynthetic capacity to concurrent changes in leaf nitrogen content only. To improve the predictions of the vegetation models, there is an urgent need to review species growth conditions and their seasonal response to changing climate. We sampled the global distribution of the Vcmax (maximum carboxylation rates) data of various species across different environmental gradients from the literature and standardized its value to 25 degree Celcius. We found that species explained the largest variation in (1) the photosynthetic capacity and (2) the proportion of nitrogen allocated for rubisco (PNcb). Surprisingly, climate variables explained more variations in photosynthetic capacity as well as PNcb than leaf nitrogen content and/or specific leaf area. The chief climate variables that explain variation in photosynthesis and PNcb were radiation, temperature and daylength. Our analysis suggests that species have the greatest control over photosynthesis and PNcb. Further, compared to leaf nitrogen content and/or specific leaf area, climate variables have more control over photosynthesis and PNcb. Therefore, climate variables should be incorporated in the global vegetation models when making predictions about the photosynthetic capacity.

  17. Immobilization technology for krypton in amorphous zeolite

    International Nuclear Information System (INIS)

    Takusagawa, Atsushi; Ishiyama, Keiichi

    1989-01-01

    Radioactive krypton recovered from the offgas of a reprocessing plant requires long-term storage on the order of 100 years. Immobilization technology for krypton into amorphous zeolite 5A is considered one of the best methods for long-term storage. In this report, conditions for immobilization treatment and stability of amorphous zeolite 5A loaded krypton against heat, radiation and water are discussed, and a treatment system using this technology is described. (author)

  18. Immobilization Technologies in Probiotic Food Production

    Directory of Open Access Journals (Sweden)

    Gregoria Mitropoulou

    2013-01-01

    Full Text Available Various supports and immobilization/encapsulation techniques have been proposed and tested for application in functional food production. In the present review, the use of probiotic microorganisms for the production of novel foods is discussed, while the benefits and criteria of using probiotic cultures are analyzed. Subsequently, immobilization/encapsulation applications in the food industry aiming at the prolongation of cell viability are described together with an evaluation of their potential future impact, which is also highlighted and assessed.

  19. Ceramification: A plutonium immobilization process

    Energy Technology Data Exchange (ETDEWEB)

    Rask, W.C. [Dept. of Energy, Golden, CO (United States); Phillips, A.G. [Rocky Flats Environmental Technology Site, Golden, CO (United States)

    1996-05-01

    This paper describes a low temperature technique for stabilizing and immobilizing actinide compounds using a combination process/storage vessel of stainless steel, in which measured amounts of actinide nitrate solutions and actinide oxides (and/or residues) are systematically treated to yield a solid article. The chemical ceramic process is based on a coating technology that produces rare earth oxide coatings for defense applications involving plutonium. The final product of this application is a solid, coherent actinide oxide with process-generated encapsulation that has long-term environmental stability. Actinide compounds can be stabilized as pure materials for ease of re-use or as intimate mixtures with additives such as rare earth oxides to increase their degree of proliferation resistance. Starting materials for the process can include nitrate solutions, powders, aggregates, sludges, incinerator ashes, and others. Agents such as cerium oxide or zirconium oxide may be added as powders or precursors to enhance the properties of the resulting solid product. Additives may be included to produce a final product suitable for use in nuclear fuel pellet production. The process is simple and reduces the time and expense for stabilizing plutonium compounds. It requires a very low equipment expenditure and can be readily implemented into existing gloveboxes. The process is easily conducted with less associated risk than proposed alternative technologies.

  20. Protein structural deformation induced lifetime shortening of photosynthetic bacteria light-harvesting complex LH2 excited state.

    Science.gov (United States)

    Chen, Xing-Hai; Zhang, Lei; Weng, Yu-Xiang; Du, Lu-Chao; Ye, Man-Ping; Yang, Guo-Zhen; Fujii, Ritsuko; Rondonuwu, Ferdy S; Koyama, Yasushi; Wu, Yi-Shi; Zhang, J P

    2005-06-01

    Photosynthetic bacterial light-harvesting antenna complex LH2 was immobilized on the surface of TiO(2) nanoparticles in the colloidal solution. The LH2/TiO(2) assembly was investigated by the time-resolved spectroscopic methods. The excited-state lifetimes for carotenoid-containing and carotenoidless LH2 have been measured, showing a decrease in the excited-state lifetime of B850 when LH2 was immobilized on TiO(2). The possibility that the decrease of the LH2 excited-state lifetime being caused by an interfacial electron transfer reaction between B850 and the TiO(2) nanoparticle was precluded experimentally. We proposed that the observed change in the photophysical properties of LH2 when assembled onto TiO(2) nanoparticles is arising from the interfacial-interaction-induced structural deformation of the LH2 complex deviating from an ellipse of less eccentric to a more eccentric ellipse, and the observed phenomenon can be accounted by an elliptical exciton model. Experiment by using photoinactive SiO(2) nanoparticle in place of TiO(2) and core complex LH1 instead of LH2 provide further evidence to the proposed mechanism.

  1. Biotechnological production of vanillin using immobilized enzymes.

    Science.gov (United States)

    Furuya, Toshiki; Kuroiwa, Mari; Kino, Kuniki

    2017-02-10

    Vanillin is an important and popular plant flavor, but the amount of this compound available from plant sources is very limited. Biotechnological methods have high potential for vanillin production as an alternative to extraction from plant sources. Here, we report a new approach using immobilized enzymes for the production of vanillin. The recently discovered oxygenase Cso2 has coenzyme-independent catalytic activity for the conversion of isoeugenol and 4-vinylguaiacol to vanillin. Immobilization of Cso2 on Sepabeads EC-EA anion-exchange carrier conferred enhanced operational stability enabling repetitive use. This immobilized Cso2 catalyst allowed 6.8mg yield of vanillin from isoeugenol through ten reaction cycles at a 1mL scale. The coenzyme-independent decarboxylase Fdc, which has catalytic activity for the conversion of ferulic acid to 4-vinylguaiacol, was also immobilized on Sepabeads EC-EA. We demonstrated that the immobilized Fdc and Cso2 enabled the cascade synthesis of vanillin from ferulic acid via 4-vinylguaiacol with repetitive use of the catalysts. This study is the first example of biotechnological production of vanillin using immobilized enzymes, a process that provides new possibilities for vanillin production. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Radiation technology for immobilization of bioactive materials

    International Nuclear Information System (INIS)

    1988-12-01

    Within the framework of the Agency's coordinated research programme on ''Application of Radiation Technology in Immobilization of Bioactive Materials'', the third and final research coordination meeting was held at Beijing University, Beijing, People's Republic of China, 15-18 June 1987. The present publication compiles all presentations made at the meeting. Fundamental processes for the immobilization of enzymes, antibodies, cells and drugs were developed and established using gamma radiation, electron beams and plasma discharge. Applications of various biofunctional components, immobilized by radiation techniques in different processes, were studied. A range of backbone polymers has been examined together with various monomers. Coupling procedures have been developed which are relevant to our particular requirements. Enzymes of various types and characteristics have been immobilized with considerable efficiency. The immobilized biocatalysts have been shown to possess significant activity and retention of activity on storage. There appears to be a high degree of specificity associated with the properties of the immobilised biocatalysts, their activity and the ease of their preparation. Novel additives which lower the total radiation dose in grafting have been discovered and their value in immobilization processes assessed. Potential applications include: medical (diagnostic, therapeutic), and industrial processes (fermentation, bioseparation, etc.). Refs, figs and tabs

  3. Immobilization of Dystrophin and Laminin α2-Chain Deficient Zebrafish Larvae In Vivo Prevents the Development of Muscular Dystrophy.

    Directory of Open Access Journals (Sweden)

    Mei Li

    Full Text Available Muscular dystrophies are often caused by genetic alterations in the dystrophin-dystroglycan complex or its extracellular ligands. These structures are associated with the cell membrane and provide mechanical links between the cytoskeleton and the matrix. Mechanical stress is considered a pathological mechanism and muscle immobilization has been shown to be beneficial in some mouse models of muscular dystrophy. The zebrafish enables novel and less complex models to examine the effects of extended immobilization or muscle relaxation in vivo in different dystrophy models. We have examined effects of immobilization in larvae from two zebrafish strains with muscular dystrophy, the Sapje dystrophin-deficient and the Candyfloss laminin α2-chain-deficient strains. Larvae (4 days post fertilization, dpf of both mutants have significantly lower active force in vitro, alterations in the muscle structure with gaps between muscle fibers and altered birefringence patterns compared to their normal siblings. Complete immobilization (18 hrs to 4 dpf was achieved using a small molecular inhibitor of actin-myosin interaction (BTS, 50 μM. This treatment resulted in a significantly weaker active contraction at 4 dpf in both mutated larvae and normal siblings, most likely reflecting a general effect of immobilization on myofibrillogenesis. The immobilization also significantly reduced the structural damage in the mutated strains, showing that muscle activity is an important pathological mechanism. Following one-day washout of BTS, muscle tension partly recovered in the Candyfloss siblings and caused structural damage in these mutants, indicating activity-induced muscle recovery and damage, respectively.

  4. 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

  5. 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.

  6. Biological optimization systems for enhancing photosynthetic efficiency and methods of use

    Science.gov (United States)

    Hunt, Ryan W.; Chinnasamy, Senthil; Das, Keshav C.; de Mattos, Erico Rolim

    2012-11-06

    Biological optimization systems for enhancing photosynthetic efficiency and methods of use. Specifically, methods for enhancing photosynthetic efficiency including applying pulsed light to a photosynthetic organism, using a chlorophyll fluorescence feedback control system to determine one or more photosynthetic efficiency parameters, and adjusting one or more of the photosynthetic efficiency parameters to drive the photosynthesis by the delivery of an amount of light to optimize light absorption of the photosynthetic organism while providing enough dark time between light pulses to prevent oversaturation of the chlorophyll reaction centers are disclosed.

  7. Effect of space mutation of photosynthetic characteristics of soybean varieties

    International Nuclear Information System (INIS)

    Liu Xinlei; Ma Yansong; Luan Xiaoyan; Man Weiqun; Xu Dechun; Meng Lifen; Fu Lixin; Zhao Xiao'nan; Liu Qi

    2012-01-01

    In order to elucidate the response of the photosynthetic traits of soybean to space mutation, three soybean varieties (lines) of Heinong 48, Heinong 44 and Ha 2291-Y were carried by artificial satellite in 2006 and the net photo synthetic rate (Pn), stomatal conductance (Cond), intercellular CO 2 concentration (Ci) and stomatal resistance (Rs) from SP 1 to SP 4 generation were determined. The results showed that space mutation affected photosynthesis traits of soy bean. The photosynthetic rate of soybean varieties by space mutation occurred different levels of genetic variation and the positive mutation rate were higher. Coefficient of variation among generations were SP 2 >SP 3 >SP 4 >CK. Results suggest that space mutation can effectively create soybean materials with higher photosynthetic rate. (authors)

  8. Cyanobacteria as photosynthetic biocatalysts: a systems biology perspective.

    Science.gov (United States)

    Gudmundsson, Steinn; Nogales, Juan

    2015-01-01

    The increasing need to replace oil-based products and to address global climate change concerns has triggered considerable interest in photosynthetic microorganisms. Cyanobacteria, in particular, have great potential as biocatalysts for fuels and fine-chemicals. During the last few years the biotechnological applications of cyanobacteria have experienced an unprecedented increase and the use of these photosynthetic organisms for chemical production is becoming a tangible reality. However, the field is still immature and many concerns about the economic feasibility of the biotechnological potential of cyanobacteria remain. In this review we describe recent successes in biofuel and fine-chemical production using cyanobacteria. We discuss the role of the photosynthetic metabolism and highlight the need for systems-level metabolic optimization in order to achieve the true potential of cyanobacterial biocatalysts.

  9. Superradiance Transition and Nonphotochemical Quenching in Photosynthetic Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Berman, Gennady Petrovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nesterov, Alexander [Universidad de Guadalajara, Departamento de Fısica, Jalisco (Mexico); Lopez, Gustavo [Universidad de Guadalajara, Departamento de Fısica, Jalisco (Mexico); Sayre, Richard Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-23

    Photosynthetic organisms have evolved protective strategies to allow them to survive in cases of intense sunlight fluctuation with the development of nonphotochemical quenching (NPQ). This process allows light harvesting complexes to transfer the excess sunlight energy to non-damaging quenching channels. This report compares the NPQ process with the superradiance transition (ST). We demonstrated that the maximum of the NPQ efficiency is caused by the ST to the sink associated with the CTS. However, experimental verifications are required in order to determine whether or not the NPQ regime is associated with the ST transition for real photosynthetic complexes. Indeed, it can happen that, in the photosynthetic apparatus, the NPQ regime occurs in the “non-optimal” region of parameters, and it could be independent of the ST.

  10. Ligand binding to G protein-coupled receptors in tethered cell membranes

    DEFF Research Database (Denmark)

    Martinez, Karen L.; Meyer, Bruno H.; Hovius, Ruud

    2003-01-01

    for the surface immobilization of membrane proteins was developed using the prototypic seven transmembrane neurokinin-1 receptor. The receptor was expressed as a biotinylated protein in mammalian cells. Membranes from cell homogenates were selectively immobilized on glass surfaces covered with streptavidin. TIRF...... measurements showed that a fluorescent agonist binds to the receptor on the sensor surface with similar affinity as to the receptor in live cells. This approach offers the possibility to investigate minute amounts of membrane protein in an active form and in its native environment without purification....

  11. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gregory Kremer; Dr. David J. Bayless; Dr. Morgan Vis; Dr. Michael Prudich; Dr. Keith Cooksey; Dr. Jeff Muhs

    2002-07-15

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 4/2/2001 through 7/01/2002. Most of the achievements are milestones in our efforts to complete the tasks and subtasks that constitute the project objectives, and we are currently on schedule to complete Phase I activities by 10/2002, the milestone date from the original project timeline. As indicated in the list of accomplishments below, our efforts are focused on improving the design of the bioreactor test system, evaluating candidate organisms and growth surfaces, and scaling-up the test facilities from bench scale to pilot scale. Specific results and accomplishments for the second quarter of 2002 include: Organisms and Growth Surfaces: (1) Our collection of cyanobacteria, isolated in YNP was increased to 15 unialgal cultures. (2) Illumination rate about 50 {micro}E/m{sup 2}/sec is not saturated for the growth of 1.2 s.c. (2) isolate. The decrease of illumination rate led to the decrease of doubling time of this isolate. (3) The positive effect of Ca{sup 2+} on the growth of isolate 1.2 s.c. (2) without Omnisil was revealed, though Ca{sup 2+} addition was indifferent for the growth of this isolate at the presence of Omnisil. (4) Calcium addition had a positive effect on the generation of cyanobacterial biofilm on Omnisil surface. (5) The survivability problems with the Tr9.4 organism on Omnisil screens in the CRF2 model-scale bioreactor have been solved. The problems were related to the method used to populate the growth surfaces. When pre-populated screens were placed in the bioreactor the microalgae died within 72 hours, but when the microalgae were cultured while in place in the bioreactor using a continuous-population method they grew well inside of the CRF2 test system and survived for the full 7-day test duration. CRF2 tests will continue as soon as the new combined drip system/harvesting system header pipe

  12. Functionalization of PVC membrane with ss oligonucleotides for a potentiometric biosensor.

    Science.gov (United States)

    Shishkanova, T V; Volf, R; Krondak, M; Král, V

    2007-05-15

    A novel application of a single stranded (ss) oligonucleotide as an active component of polymeric membrane in an ion-selective electrode (ISE) is described. The original oligonucleotides, oligo(dA)(15), modified by cholesterol, triphenylmethyl and hexadecyl derivatives, were immobilized into poly(vinyl chloride) (PVC) membrane using extraction protocol. In parallel, the adsorption protocol was used to immobilize unmodified oligo(dA)(15) on the PVC membrane based on tridodecylmethyammonium chloride (TDDMA(+)Cl(-)). Immobilization of ss oligonucleotide probe through spacer was more effective for the potentiometric detection of the hybridization between complementary oligonucleotides. It was found that cholesterol-oligo(dA)(15) modified membranes were sensitive toward complementary oligo(dT)(15) in the concentration range 2-80 nM at pH 7. An explanation for the detection mechanism is proposed.

  13. Energy transfer in real and artificial photosynthetic systems

    Energy Technology Data Exchange (ETDEWEB)

    Hindman, J.C.; Hunt, J.E.; Katz, J.J.

    1995-02-01

    Fluorescence emission from the photosynthetic organisms Tribonema aequale, Anacystis nidulau, and Chlorelia vulgais and from some chlorophyll model systems have been recorded as a function of excitation wavelength and temperature. Considerable similarity was observed in the effects of excitation wavelength and temperature on the fluorescence from intact photosynthetic organisms and the model systems. The parallelism in behavior suggest that self-assembly processes may occur in both the in vivo and in vitro systems that give rise to chlorophyll species at low temperature that may differ significantly from those present at ambient temperatures.

  14. Recent development of ionic liquid membranes

    Directory of Open Access Journals (Sweden)

    Junfeng Wang

    2016-04-01

    Full Text Available The interest in ionic liquids (IL is motivated by its unique properties, such as negligible vapor pressure, thermal stability, wide electrochemical stability window, and tunability of properties. ILs have been highlighted as solvents for liquid–liquid extraction and liquid membrane separation. To further expand its application in separation field, the ionic liquid membranes (ILMs and its separation technology have been proposed and developed rapidly. This paper is to give a comprehensive overview on the recent applications of ILMs for the separation of various compounds, including organic compounds, mixed gases, and metal ions. Firstly, ILMs was classified into supported ionic liquid membranes (SILMs and quasi-solidified ionic liquid membranes (QSILMs according to the immobilization method of ILs. Then, preparation methods of ILMs, membrane stability as well as applications of ILMs in the separation of various mixtures were reviewed. Followed this, transport mechanisms of gaseous mixtures and organic compounds were elucidated in order to better understand the separation process of ILMs. This tutorial review intends to not only offer an overview on the development of ILMs but also provide a guide for ILMs preparations and applications. Keywords: Ionic liquid membrane, Supported ionic liquid membrane, Qusai-solidified ionic liquid membrane, Stability, Application

  15. Fabrication of Ceramic Membrane Chromatography for Biologics Purification

    Directory of Open Access Journals (Sweden)

    Maizirwan Mel

    2011-12-01

    Full Text Available Chromatography is one of the most important separation processes of choice for the recovery/purification of proteins and complex bio-structures. Fabrication of chromatographic membranes and their efficiency in the chromatography process has been the subject of many recent researches. In this study, a coin-like, 13 mm diameter and 3 mm thick, ceramic membrane was fabricated to be used as a chromatographic medium. The membrane is used to replace the conventional resin-based chromatography columns. Hydroxyapatite (HA powder was used as a material for the membrane fabrication. In this project, a HA powder was produced using starch as pore creating agents. Characterization processes were done for the ceramic membrane using the suitable apparatuses. Three parameters of the fabrication process (starch wt %, compaction pressure and sintering temperature were manipulated to optimize the performance of the membrane. The fabricated membrane was placed in a (FPLC system to be tested for its performance as an adsorptive membrane. (IMAC process was run by immobilizing Ni2+ ions at the membrane particles surfaces. NP protein of the (NDV was used to test the membrane's ability to bind Histidine-tagged proteins. The optimum set of process parameters that yielded in the highest porosity and good chromatogram was determined to be 5 wt % starch, 3000 psi compaction pressure and 1100°C sintering temperature.ABSTRAK: Kromatografi merupakan satu daripada proses pengasingan yang penting yang dipilih untuk perolehan/penapisan protein dan biostruktur yang kompleks. Pemfabrikatan membran kromatografi dan kecekapannya dalam proses kromatografi merupakan fokus beberapa kajian terkini. Dalam kajian ini, membran seramik berbentuk duit syiling, berdiameter 13 mm dengan ketebalan 3 mm, direka untuk digunakan sebagai perantara kromatografi. Membran ini digunakan untuk menggantikan turus kromatografi berasaskan resin yang lazim. Serbuk hidroksiapatit (HA digunakan sebagai bahan

  16. 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...

  17. Reversible thermal denaturation of immobilized rhodanese

    International Nuclear Information System (INIS)

    Horowitz, P.; Bowman, S.

    1987-01-01

    For the first time, the enzyme rhodanese had been refolded after thermal denaturation. This was previously not possible because of the strong tendency for the soluble enzyme to aggregate at temperatures above 37 degrees C. The present work used rhodanese that was covalently coupled to a solid support under conditions that were found to preserve enzyme activity. Rhodanese was immobilized using an N-hydroxymalonimidyl derivative of Sepharose containing a 6-carbon spacer. The number of immobilized competent active sites was measured by using [ 35 S]SO 3 (2-) to form an active site persulfide that is the obligatory catalytic intermediate. Soluble enzyme was irreversibly inactivated in 10 min at 52 degrees C. The immobilized enzyme regained at least 30% of its original activity even after boiling for 20 min. The immobilized enzyme had a Km and Vmax that were each approximately 3 times higher than the corresponding values for the native enzyme. After preincubation at high temperatures, progress curves for the immobilized enzyme showed induction periods of up to 5 min before attaining apparently linear steady states. The pH dependence of the activity was the same for both the soluble and the immobilized enzyme. These results indicate significant stabilization of rhodanese after immobilization, and instabilities caused by adventitious solution components are not the sole reasons for irreversibility of thermal denaturation seen with the soluble enzyme. The results are consistent with models for rhodanese that invoke protein association as a major cause of inactivation of the enzyme. Furthermore, the induction period in the progress curves is consistent with studies which show that rhodanese refolding proceeds through intermediate states

  18. Characteristics of Immobilized Urease on Grafted Alginate Bead Systems

    Directory of Open Access Journals (Sweden)

    Enas N. Danial

    2015-04-01

    Full Text Available This study evaluated the biological importance of immobilized urease enzyme over the free urease. The support material used for urease immobilization was alginate. Generally, the immobilization of urease in alginate gel showed a marked increase in Km and Vmax. However, the immobilized urease showed higher thermal stability than that of free enzyme. The rate of thermal inactivation of the immobilized enzyme decreased due to entrapment in gel matrix. Also, the activity of the immobilized urease was more stable in retention than that of the free enzyme during the storage in solution, although the activity of the immobilized enzyme was lower in comparison with the free enzyme. A stable immobilized system and long storage life are convenient for applications that would not be feasible with a soluble enzyme system. These results highlighted the technical and biochemical benefits of immobilized urease over the free enzyme.

  19. Surface-modified anodic aluminum oxide membrane with hydroxyethyl celluloses as a matrix for bilirubin removal.

    Science.gov (United States)

    Xue, Maoqiang; Ling, Yisheng; Wu, Guisen; Liu, Xin; Ge, Dongtao; Shi, Wei

    2013-01-01

    Microporous anodic aluminum oxide (AAO) membranes were modified by 3-glycidoxypropyltrimethoxysilane to produce terminal epoxy groups. These were used to covalently link hydroxyethyl celluloses (HEC) to amplify reactive groups of AAO membrane. The hydroxyl groups of HEC-AAO composite membrane were further modified with 1,4-butanediol diglycidyl ether to link arginine as an affinity ligand. The contents of HEC and arginine of arginine-immobilized HEC-AAO membrane were 52.1 and 19.7mg/g membrane, respectively. As biomedical adsorbents, the arginine-immobilized HEC-AAO membranes were tested for bilirubin removal. The non-specific bilirubin adsorption on the unmodified HEC-AAO composite membranes was 0.8mg/g membrane. Higher bilirubin adsorption values, up to 52.6mg/g membrane, were obtained with the arginine-immobilized HEC-AAO membranes. Elution of bilirubin showed desorption ratio was up to 85% using 0.3M NaSCN solution as the desorption agent. Comparisons equilibrium and dynamic capacities showed that dynamic capacities were lower than the equilibrium capacities. In addition, the adsorption mechanism of bilirubin and the effects of temperature, initial concentration of bilirubin, albumin concentration and ionic strength on adsorption were also investigated. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Design of a papain immobilized antimicrobial food package with curcumin as a crosslinker.

    Directory of Open Access Journals (Sweden)

    Cynthya Maria Manohar

    Full Text Available Contamination of food products by spoilage and pathogenic microorganisms during post process handling is one of the major causes for food spoilage and food borne illnesses. The present green sustainable approach describes the covalent immobilization of papain to LDPE (low density polyethylene, HDPE (high density polyethylene, LLDPE (linear low density polyethylene and PCL (polycaprolactam with curcumin as the photocrosslinker. About 50% of curcumin and 82-92% of papain were successfully immobilized on these polymers. After 30 days, the free enzyme retained 87% of its original activity, while the immobilized enzyme retained more than 90% of its activity on these polymers. Papain crosslinked to LLDPE exhibited the best antibiofilm properties against Acinetobacter sp. KC119137.1 and Staphylococcus aureus NCIM 5021 when compared to the other three polymers, because of the highest amount of enzyme immobilized on this surface. Papain acts by damaging the cell membrane. The enzyme is able to reduce the amount of carbohydrate and protein contents in the biofilms formed by these organisms. Meat wrapped with the modified LDPE and stored at 4°C showed 9 log reduction of these organisms at the end of the seventh day when compared to samples wrapped with the bare polymer. This method of crosslinking can be used on polymers with or without functional groups and can be adopted to bind any type of antimicrobial agent.

  1. A Potentiometric Formaldehyde Biosensor Based on Immobilization of Alcohol Oxidase on Acryloxysuccinimide-modified Acrylic Microspheres

    Directory of Open Access Journals (Sweden)

    Lee Yook Heng

    2010-11-01

    Full Text Available A new alcohol oxidase (AOX enzyme-based formaldehyde biosensor based on acrylic microspheres has been developed. Hydrophobic poly(n-butyl acrylate-N-acryloxy-succinimide [poly(nBA-NAS] microspheres, an enzyme immobilization matrix, was synthesized using photopolymerization in an emulsion form. AOX-poly(nBA-NAS microspheres were deposited on a pH transducer made from a layer of photocured and self-plasticized polyacrylate membrane with an entrapped pH ionophore coated on a Ag/AgCl screen printed electrode (SPE. Oxidation of formaldehyde by the immobilized AOX resulted in the production of protons, which can be determined via the pH transducer. Effects of buffer concentrations, pH and different amount of immobilization matrix towards the biosensor’s analytical performance were investigated. The formaldehyde biosensor exhibited a dynamic linear response range to formaldehyde from 0.3–316.2 mM and a sensitivity of 59.41 ± 0.66 mV/decade (R2 = 0.9776, n = 3. The lower detection limit of the biosensor was 0.3 mM, while reproducibility and repeatability were 3.16% RSD (relative standard deviation and 1.11% RSD, respectively (n = 3. The use of acrylic microspheres in the potentiometric formaldehyde biosensor improved the biosensor’s performance in terms of response time, linear response range and long term stability when compared with thick film immobilization methods.

  2. Design of a Papain Immobilized Antimicrobial Food Package with Curcumin as a Crosslinker

    Science.gov (United States)

    Sivakumar, Ponnurengam Malliappan; Doble, Mukesh

    2015-01-01

    Contamination of food products by spoilage and pathogenic microorganisms during post process handling is one of the major causes for food spoilage and food borne illnesses. The present green sustainable approach describes the covalent immobilization of papain to LDPE (low density polyethylene), HDPE (high density polyethylene), LLDPE (linear low density polyethylene) and PCL (polycaprolactam) with curcumin as the photocrosslinker. About 50% of curcumin and 82-92% of papain were successfully immobilized on these polymers. After 30 days, the free enzyme retained 87% of its original activity, while the immobilized enzyme retained more than 90% of its activity on these polymers. Papain crosslinked to LLDPE exhibited the best antibiofilm properties against Acinetobacter sp. KC119137.1 and Staphylococcus aureus NCIM 5021 when compared to the other three polymers, because of the highest amount of enzyme immobilized on this surface. Papain acts by damaging the cell membrane. The enzyme is able to reduce the amount of carbohydrate and protein contents in the biofilms formed by these organisms. Meat wrapped with the modified LDPE and stored at 4°C showed 9 log reduction of these organisms at the end of the seventh day when compared to samples wrapped with the bare polymer. This method of crosslinking can be used on polymers with or without functional groups and can be adopted to bind any type of antimicrobial agent. PMID:25906061

  3. Design of a papain immobilized antimicrobial food package with curcumin as a crosslinker.

    Science.gov (United States)

    Manohar, Cynthya Maria; Prabhawathi, Veluchamy; Sivakumar, Ponnurengam Malliappan; Doble, Mukesh

    2015-01-01

    Contamination of food products by spoilage and pathogenic microorganisms during post process handling is one of the major causes for food spoilage and food borne illnesses. The present green sustainable approach describes the covalent immobilization of papain to LDPE (low density polyethylene), HDPE (high density polyethylene), LLDPE (linear low density polyethylene) and PCL (polycaprolactam) with curcumin as the photocrosslinker. About 50% of curcumin and 82-92% of papain were successfully immobilized on these polymers. After 30 days, the free enzyme retained 87% of its original activity, while the immobilized enzyme retained more than 90% of its activity on these polymers. Papain crosslinked to LLDPE exhibited the best antibiofilm properties against Acinetobacter sp. KC119137.1 and Staphylococcus aureus NCIM 5021 when compared to the other three polymers, because of the highest amount of enzyme immobilized on this surface. Papain acts by damaging the cell membrane. The enzyme is able to reduce the amount of carbohydrate and protein contents in the biofilms formed by these organisms. Meat wrapped with the modified LDPE and stored at 4°C showed 9 log reduction of these organisms at the end of the seventh day when compared to samples wrapped with the bare polymer. This method of crosslinking can be used on polymers with or without functional groups and can be adopted to bind any type of antimicrobial agent.

  4. Rapid detection of food pathogens using RNA aptamers-immobilized slide.

    Science.gov (United States)

    Maeng, Jin-Soo; Kim, Namsoo; Kim, Chong-Tai; Han, Seung Ryul; Lee, Young Ju; Lee, Seong-Wook; Lee, Myung-Hyun; Cho, Yong-Jin

    2012-07-01

    The purpose of this study was to develop a simple and rapid detection system for foodborne bacteria, which consisted of an optical microscope and its slide chip with artificial antibodies, or RNA aptamers. From an RNA pool, three each RNA aptamers were built by the method of SELEX (systematic evolution of ligands by exponential enrichment) for components of cell wall, LPS (lipopolysaccharide) from E. coli O157:H7, teichoic acid from Staphylococcus aureus and a cell membrane protein of OmpC from Salmonella typhimurium, respectively. These aptamers were hybridized with thiol-conjugated 16 dT-linker molecules in order to be immobilized on silver surface which was, in advance, fabricated on glass slide, using a spin-coating method. To confirm that each aptamers retained its specific binding activities to their antigenic live bacteria, microscopic view of bound cells immobilized on silver film were observed. Furthermore, we observed the fluorescence-emitting bacteria-aptamer complex immobilized on silver film after adding RNA aptamers hybridized with fluorophore, FAM-conjugated 16 dT-linker molecules. As a result, the RNA aptamers-immobilized slide system developed in this study was a useful new tool to rapidly monitor individual food pathogens.

  5. 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- ...

  6. Contrasting Responses of Marine and Freshwater Photosynthetic Organisms to UVB Radiation: A Meta-Analysis

    KAUST Repository

    Jin, Peng; Duarte, Carlos M.; Agusti, Susana

    2017-01-01

    artificial lamps. We found that marine photosynthetic organisms tend to be more sensitive than freshwater photosynthetic organisms to UVB radiation; responses to either decreased or increased UVB radiation vary among taxa; the mortality rate is the most

  7. On the photosynthetic and devlopmental responses of leaves to the spectral composition of light

    NARCIS (Netherlands)

    Hogewoning, S.W.

    2010-01-01

    Key words: action spectrum, artificial solar spectrum, blue light, Cucumis sativus, gas-exchange, light-emitting diodes (LEDs), light interception, light quality, non-photosynthetic pigments, photo-synthetic capacity, photomorphogenesis, photosystem excitation balance, quantum yield, red light.

  8. Excess Weapons Plutonium Immobilization in Russia

    International Nuclear Information System (INIS)

    Jardine, L.; Borisov, G.B.

    2000-01-01

    The joint goal of the Russian work is to establish a full-scale plutonium immobilization facility at a Russian industrial site by 2005. To achieve this requires that the necessary engineering and technical basis be developed in these Russian projects and the needed Russian approvals be obtained to conduct industrial-scale immobilization of plutonium-containing materials at a Russian industrial site by the 2005 date. This meeting and future work will provide the basis for joint decisions. Supporting R and D projects are being carried out at Russian Institutes that directly support the technical needs of Russian industrial sites to immobilize plutonium-containing materials. Special R and D on plutonium materials is also being carried out to support excess weapons disposition in Russia and the US, including nonproliferation studies of plutonium recovery from immobilization forms and accelerated radiation damage studies of the US-specified plutonium ceramic for immobilizing plutonium. This intriguing and extraordinary cooperation on certain aspects of the weapons plutonium problem is now progressing well and much work with plutonium has been completed in the past two years. Because much excellent and unique scientific and engineering technical work has now been completed in Russia in many aspects of plutonium immobilization, this meeting in St. Petersburg was both timely and necessary to summarize, review, and discuss these efforts among those who performed the actual work. The results of this meeting will help the US and Russia jointly define the future direction of the Russian plutonium immobilization program, and make it an even stronger and more integrated Russian program. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing the work into one place for four days to review and discuss their work with each other; and (2) Publish a meeting summary and a proceedings to compile reports of all the

  9. Studies Regarding the Membranous Support of a Glucose Biosensor Based on Gox

    Directory of Open Access Journals (Sweden)

    Otilia Bizerea-Spiridon

    2010-05-01

    Full Text Available To obtain glucose biosensors based on glucose oxidase (GOx, the enzyme can be immobilized on the sensitive surface of a glass electrode by different techniques: deposition on membranous support (cellophane or other macromolecular material or entrapment in a matrix. Deposition on membranous support also involves cross-linking with glutaraldehyde or entrapment in silica gel, following the sol-gel procedure. The aim of this preliminary work was to study the influence of cellophane replacement with a PVA based membranous support on the glucose biosensor performance. The data obtained at pH measurements of buffer solutions with cellophane and PVA membranous supports respectively, show that the PVA based membrane assures superior performances of the biosensor for low glucose concentrations determination (about 10-4 M. These results allow the transition to an improved immobilization technique, namely the enzyme entrapment in membranous material.

  10. Chitosan/Carboxymethylcellulose/Ionic Liquid/Ag(0) Nanoparticles Form a Membrane with Antimicrobial Activity

    International Nuclear Information System (INIS)

    Quadros, C.; Faria, V.W.; Scheeren, C.W.; Klein, M.P.; Hertz, P.F.

    2013-01-01

    Silver metal nanoparticles were immobilized in chitosan/carboxymethylcellulose/BMI.BF4(1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid) (CS/CMC/IL) to form polymeric membrane with 20 μm thickness. The CS/CMC/IL polymeric membrane was prepared using a simple solution blending method. Irregularly shaped Ag(0) nanoparticles with monomodal size distributions of nm Ag(0) were immobilized in the membrane. The presence of small Ag(0) nanoparticles induced an augmentation in the CS/CMC/IL film surface areas. The CS/CMC/IL membrane containing Ag(0) showed increase antimicrobial activity the Ag(0) concentration increased up to saturation at 10 mg. CS/CMC/IL membrane that contains Ag(0) nanoparticles has enhanced durability of the membrane and exhibited stronger antimicrobial activity against Escherichia coli and Staphylococcus aureus.

  11. Dye-Affinity Nanofibrous Membrane for Adsorption of Lysozyme: Preparation and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Steven Sheng-Shih Wang

    2018-01-01

    Full Text Available Polyacrylonitrile (PAN nanofibrous membrane was prepared by an electrospinning technique. After heat treatment and alkaline hydrolysis, the weak ion exchange membrane was grafted with chitosan molecule and then covalently immobilized with a Cibacron Blue F3GA (CB. Fibre diameter, porosity and pore size of the membrane and immobilized dye density were characterized. Furthermore, the membrane was applied to evaluate the binding performance of lysozyme under various operating parameters (pH, chitosan mass per volume ratio, dye concentration, ionic strength and temperature in batch mode. The experimental results were directly applied to purify lysozyme from chicken egg white by membrane chromatography. The results showed that the capture efficiency, recovery yield and purification factor were 90 and 87 %, and 47-fold, respectively, in a single step. The binding capacity remained consistent after five repeated cycles of adsorption-desorption operations. This work demonstrates that the dye-affinity nanofibrous membrane holds great potential for purification of lysozyme from real feedstock.

  12. Disposition of surplus fissile materials via immobilization

    International Nuclear Information System (INIS)

    Gray, L.W.; Kan, T.; Sutcliffe, W.G.; McKibben, J.M.; Danker, W.

    1995-01-01

    In the Cold War aftermath, the US and Russia have agreed to large reductions in nuclear weapons. To aid in the selection of long-term management options, the USDOE has undertaken a multifaceted study to select options for storage and disposition of surplus plutonium (Pu). One disposition alternative being considered is immobilization. Immobilization is a process in which surplus Pu would be embedded in a suitable material to produce an appropriate form for ultimate disposal. To arrive at an appropriate form, we first reviewed published information on HLW immobilization technologies to identify forms to be prescreened. Surviving forms were screened using multi-attribute utility analysis to determine promising technologies for Pu immobilization. We further evaluated the most promising immobilization families to identify and seek solutions for chemical, chemical engineering, environmental, safety, and health problems; these problems remain to be solved before we can make technical decisions about the viability of using the forms for long-term disposition of Pu. All data, analyses, and reports are being provided to the DOE Office of Fissile Materials Disposition to support the Record of Decision that is anticipated in Summer of 1996

  13. Production of cellulase from immobilized Trichoderma reesei

    International Nuclear Information System (INIS)

    Kasai, Noboru; Tamada, Masao; Kumakura, Minoru

    1989-05-01

    This report completed the results that obtained on the study of the enzyme activity in the culture of immobilized Trichoderma reesei cells in flask scale (100ml) and bench scale (30l). In the flask scale culture, the batch and repeated batch culture were carried out, and in the bench scale culture, the batch, repeated batch and continuous culture were done by using a culture equipment that is an unit process of the bench scale test plant for saccharification of cellulosic wastes. The enzyme activity of the immobilized cells was higher than that of the intact cells in the flask scale culture and it was confirmed that the enzyme activity was not decreased on the repeated batch culture of six times even. In the bench scale culture, it was found that a optimum culture condition of the immobilized cells was not different from that of the free cells and the immobilized cells gave the enzyme solution with a high enzyme activity in the culture condition of 450rpm stirring speed and air supply of 0.1v/v/m above. The technique of the repeated batch and continuous culture for long times in bench scale without contamination was established. The enzyme activity of the immobilized cells in continuous culture became to be 85 % to that in batch culture and it was found that the enzyme solution with high enzyme activity was continuously obtained in the continuous culture for long times. (author)

  14. Haloalkane hydrolysis with an immobilized haloalkane dehalogenase.

    Science.gov (United States)

    Dravis, B C; Swanson, P E; Russell, A J

    2001-11-20

    Haloalkane dehalogenase from Rhodococcus rhodochrous was covalently immobilized onto a polyethyleneimine impregnated gamma-alumina support. The dehalogenating enzyme was found to retain greater than 40% of its original activity after immobilization, displaying an optimal loading (max. activity/supported protein) of 70 to 75 mg/g with an apparent maximum (max. protein/support) of 156 mg/g. The substrate, 1,2,3-trichloropropane, was found to favorably partition (adsorb) onto the inorganic alumina carrier (10 to 20 mg/g), thereby increasing the local reactant concentration with respect to the catalyst's environment, whereas the product, 2,3-dichloropropan-1-ol, demonstrated no affinity. Additionally, the inorganic alumina support exhibited no adverse effects because of solvent/component incompatibilities or deterioration due to pH variance (pH 7.0 to 10.5). As a result of the large surface area to volume ratio of the support matrix and the accessibility of the bound protein, the immobilized biocatalyst was not subject to internal mass transfer limitations. External diffusional restrictions could be eliminated with simple agitation (mixing speed: 50 rpm; flux: 4.22 cm/min). The pH-dependence of the immobilized dehalogenase was essentially the same as that for the native enzyme. Finally, both the thermostability and resistance toward inactivation by organic solvent were improved by more than an order of magnitude after immobilization. Copyright 2001 John Wiley & Sons, Inc.

  15. FT-IR microspectroscopy characterization of supports for enzyme immobilization in biosensing applications

    Science.gov (United States)

    Portaccio, M.; Della Ventura, B.; Gabrovska, K.; Marinov, I.; Godjevargova, T.; Mita, D. G.; Lepore, M.

    2010-04-01

    The investigation of materials suitable for enzyme immobilization in biosensing applications has a widespread interest. There are many studies on physico-chemical properties of these materials at macroscopic level but few studies have been devoted to examine and correlate these properties at microscopic level. FT-IR spectroscopy with Micro-Attenuated Total Reflection (Micro-ATR) approach can be extremely useful for understanding a variety of aspects of materials which can be used for optimising immobilization procedures. Moreover, this experimental approach is particularly simple to use (no sample preparation is required) and minimally invasive. Using a Perkin Elmer Spectrum One FT-IR spectrometer equipped with a mercury-cadmium-telluride detector and a micro-ATR element we investigated different materials used for immobilization procedures with various enzymes widely used for biosensing in environmental and clinical applications. In particular, composite membranes constituted by a chemically modified poly-acrylonitrile (PAN) membrane plus layers of tethered chitosan of different molecular weight have been examined. Also silica gel matrices without and with glucose oxidase have been investigated. Spectra have been analysed and the contribution of principal functional groups has been evidenced.

  16. Enhanced Practical Photosynthetic CO2 Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Kremer; David J. Bayless; Morgan Vis; Michael Prudich; Keith Cooksey; Jeff Muhs

    2006-01-15

    This final report highlights significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation Project during the period from 10/1/2001 through 01/02/2006. As indicated in the list of accomplishments below, our efforts during this project were focused on the selection of candidate organisms and growth surfaces and initiating long-term tests in the bench-scale and pilot-scale bioreactor test systems. Specific results and accomplishments for the program include: (1) CRF-2 test system: (a) Sampling test results have shown that the initial mass of algae loaded into the Carbon Recycling Facility Version 2 (CRF-2) system can be estimated with about 3% uncertainty using a statistical sampling procedure. (b) The pressure shim header pipe insert design was shown to have better flow for harvesting than the drilled-hole design. (c) The CRF-2 test system has undergone major improvements to produce the high flow rates needed for harvesting (as determined by previous experiments). The main changes to the system are new stainless steel header/frame units, with increased flow capacity and a modified pipe-end-sealing method to improve flow uniformity, and installation and plumbing for a new high flow harvesting pump. Qualitative system tests showed that the harvesting system performed wonderfully, cleaning the growth surfaces within a matter of seconds. (d) Qualitative tests have shown that organisms can be repopulated on a harvested section of a bioreactor screen, demonstrating that continuous bioreactor operation is feasible, with continuous cycles of harvesting and repopulating screens. (e) Final preparations are underway for quantitative, long-term tests in the CRF-2 with weekly harvesting. (2) Pilot-scale test system: (a) The construction of the pilot-scale bioreactor was completed, including the solar collector and light distribution system. Over the course of the project, the solar collector used in the light delivery system showed some degradation, but

  17. Effects of gibberellic acid on growth and photosynthetic pigments of ...

    African Journals Online (AJOL)

    The aim of this study was to improve growth performance by enhancing the photosynthetic pigments and enzyme carbonic anhydrase (CA) activity of Hibiscus sabdariffa L. (cv. Sabahia 17) under NaCl stress. Under non-saline condition, application of GA3 enhanced growth parameters (shoot length, shoot fresh weight (FW) ...

  18. Continuous Cultivation of Photosynthetic Bacteria for Fatty Acids Production

    DEFF Research Database (Denmark)

    Kim, Dong-Hoon; Lee, Ji-Hye; Hwang, Yuhoon

    2013-01-01

    In the present work, we introduced a novel approach for microbial fatty acids (FA) production. Photosynthetic bacteria, Rhodobacter sphaeroides KD131, were cultivated in a continuous-flow, stirred-tank reactor (CFSTR) at various substrate (lactate) concentrations.At hydraulic retention time (HRT)....... sphaeroides was around 35% of dry cell weight, mainly composed of vaccenic acid (C18:1, omega-7)....

  19. Effect of Photosynthetic Photon Flux Density on Carboxylation Efficiency 1

    Science.gov (United States)

    Weber, James A.; Tenhunen, John D.; Gates, David M.; Lange, Otto L.

    1987-01-01

    The effect of photosynthetic photon flux density (PPFD) on photosynthetic response (A) to CO2 partial pressures between 35 pascals and CO2 compensation point (Γ) was investigated, especially below PPFD saturation. Spinacia oleracea cv `Atlanta,' Glycine max cv `Clark,' and Arbutus unedo were studied in detail. The initial slope of the photosynthetic response to CO2 (∂A/∂C[Γ]) was constant above a PPFD of about 500 to 600 micromoles per square meter per second for all three species; but declined rapidly with PPFD below this critical level. For Γ there was also a critical PPFD (approximately 200 micromoles per square meter per second for S. oleracea and G. max; 100 for A. unedo) above which Γ was essentially constant, but below which Γ increased with decreasing PPFD. All three species showed a dependence of ∂A/∂C(Γ) on PPFD at low PPFD. Simulated photosynthetic responses obtained with a biochemically based model of whole-leaf photosynthesis were similar to measured responses. PMID:16665640

  20. Coherent memory functions for finite systems: hexagonal photosynthetic unit

    International Nuclear Information System (INIS)

    Barvik, I.; Herman, P.

    1990-10-01

    Coherent memory functions entering the Generalized Master Equation are presented for an hexagonal model of a photosynthetic unit. Influence of an energy heterogeneity on an exciton transfer is an antenna system as well as to a reaction center is investigated. (author). 9 refs, 3 figs

  1. Effects of 1-butanol, neomycin and calcium on the photosynthetic ...

    African Journals Online (AJOL)

    ajl yemi

    Institute of Food Crops, Jiangsu High Quality Rice R&D Center, Jiangsu Academy of Agricultural Sciences, Nanjing,. Jiangsu Province, 210014, China. Accepted 31 October, 2011. The effects .... and blue light source under the open system, with the following conditions: 1200 µmol m-2s-1 photosynthetic photon flux density.

  2. Photosynthetic behaviour of Arabidopsis thaliana (Pa-1 accession ...

    African Journals Online (AJOL)

    The growth reduction observed in many plants caused by salinity is often associated with a decrease in their photosynthetic capacity. This effect could be associated with the partial stomatal closure and/or the non-stomatal limitation which involves the decrease in ribulose-1,5-bisphosphate carboxylase oxygenase ...

  3. Variability of photosynthetic pigments in the Colombian Pacific ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 111; Issue 3. Variability of photosynthetic pigments in the Colombian Pacific Ocean and its relationship with the wind field using ADEOS-I data. Efrain Rodriguez-Rubio Jose Stuardo. Volume 111 Issue 3 September 2002 pp 227-236 ...

  4. Photosynthetic Responses of Seedlings of two Indigenous Plants ...

    African Journals Online (AJOL)

    Bheema

    ABSTRACT. The potential role of exotic tree plantations in facilitating successional processes on degraded areas was evaluated in southern Ethiopia, Munessa-Shashemene forest, by examining photosynthetic responses of Bersamaabyssinica Fres. and Croton macrostachyusDel. seedlings naturally grown inside ...

  5. Abscisic acid effects on water and photosynthetic characteristics of ...

    African Journals Online (AJOL)

    The aim of this study is to compare the water and photosynthetic characteristics of two xerophilic ecotypes of Atriplex halimus (L.). Seeds collected from two different sites Djelfa and Oran are germinated in controlled greenhouse. After 6 months, the plantlets were treated 21 days with increasing concentrations of abscisic ...

  6. An Improved Method for Extraction and Separation of Photosynthetic Pigments

    Science.gov (United States)

    Katayama, Nobuyasu; Kanaizuka, Yasuhiro; Sudarmi, Rini; Yokohama, Yasutsugu

    2003-01-01

    The method for extracting and separating hydrophobic photosynthetic pigments proposed by Katayama "et al." ("Japanese Journal of Phycology," 42, 71-77, 1994) has been improved to introduce it to student laboratories at the senior high school level. Silica gel powder was used for removing water from fresh materials prior to…

  7. Photosynthetic incorporation of 14C by Stevia rebaudiana

    International Nuclear Information System (INIS)

    Ferraresi, M. de L.; Ferraresi Filho, O.; Bracht, A.

    1985-01-01

    The photosynthetic incorporation of 14 by Stevia rebaudiana specimens was investigated. The 14 C incorporation, when the isotope was furnished to the plant in form of 14 CO 2 , was rapid. After 24 hours, the radioactivity has been incorporated into a great number of compounds including pigments, terpenes, glucose, cellulose and also stevioside and its derivatives. (M.A.C.) [pt

  8. The role of energy losses in photosynthetic light harvesting

    NARCIS (Netherlands)

    Kruger, T. P. J.; van Grondelle, R.

    2017-01-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic

  9. effect of ambient levels of ozone on photosynthetic components

    African Journals Online (AJOL)

    ACSS

    To clarify the long-term effects of ambient levels of tropospheric ozone (O3) on ... (Rubisco), thus contributing to the reduction in net photosynthetic rate at the .... USA). During the measurements, atmospheric. CO2 concentrations, air ...... productivity and implications for climate change. Annual Review of Plant Biology 63:.

  10. Effect of ambient levels of ozone on photosynthetic components and ...

    African Journals Online (AJOL)

    Effect of ambient levels of ozone on photosynthetic components and radical scavenging system in leaves of African cowpea varieties. ... The O3-induced significant reduction in catalase activity was observed in Blackeye at vegetative and reproductive growth stages; and in Asontem at reproductive growth stage. On the other ...

  11. Non-photosynthetic plastids as hosts for metabolic engineering.

    Science.gov (United States)

    Mellor, Silas Busck; Behrendorff, James B Y H; Nielsen, Agnieszka Zygadlo; Jensen, Poul Erik; Pribil, Mathias

    2018-04-13

    Using plants as hosts for production of complex, high-value compounds and therapeutic proteins has gained increasing momentum over the past decade. Recent advances in metabolic engineering techniques using synthetic biology have set the stage for production yields to become economically attractive, but more refined design strategies are required to increase product yields without compromising development and growth of the host system. The ability of plant cells to differentiate into various tissues in combination with a high level of cellular compartmentalization represents so far the most unexploited plant-specific resource. Plant cells contain organelles called plastids that retain their own genome, harbour unique biosynthetic pathways and differentiate into distinct plastid types upon environmental and developmental cues. Chloroplasts, the plastid type hosting the photosynthetic processes in green tissues, have proven to be suitable for high yield protein and bio-compound production. Unfortunately, chloroplast manipulation often affects photosynthetic efficiency and therefore plant fitness. In this respect, plastids of non-photosynthetic tissues, which have focused metabolisms for synthesis and storage of particular classes of compounds, might prove more suitable for engineering the production and storage of non-native metabolites without affecting plant fitness. This review provides the current state of knowledge on the molecular mechanisms involved in plastid differentiation and focuses on non-photosynthetic plastids as alternative biotechnological platforms for metabolic engineering. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  12. Effect of maize seed laser irradiation on plant photosynthetic activity

    International Nuclear Information System (INIS)

    Antonov, M.; Stanev, V.; Velichkov, D.; Tsonev, Ts.

    1986-01-01

    Investigations were made with the two hybrids, H-708 and P x -20. The seeds were irradiated by a helium-neon quantum generator (L'vov-1 Electronica) with output power of 24 MW and 632.8 nm wave length. Once and twice irradiated seeds were sown on the 2nd, 5th and 10th day post irradiation. Changes in leaf area, chlorophyll content in the leaves, photosynthetic rate and its dependence on temperature and light, transpiration, stomatal resistance to CO 2 and total dry matter of the overground plant part were traced. Seed irradiation with laser rays did not affect the chlorophyll content of the leaves. The photosynthetic rate did not depend on the cultivar characteristics of the crop. Single and repeated irradiation of the hybrid H-708 in most case enhanced photosynthetic rate, but a similar effect was not observed in P x -20. Transpiration and CO 2 stomatal resistance were not equally affected by radiation. Laser rays enhanced the ability of the photosynthetic apparatus of the entire plants to use more efficiently high light intensities. The leaf area and the total plant dry matter increased in case of sowing on the 2nd and 5th day and a single irradiation and in case of sowing on the 5th and 10th day and twice repeated irradiations

  13. Antibacterial activity on electrospun poly(lactide-co-glycolide) based membranes via Magainin II grafting

    Energy Technology Data Exchange (ETDEWEB)

    Yüksel, Emre; Karakeçili, Ayşe, E-mail: akarakecili@eng.ankara.edu.tr

    2014-12-01

    An antimicrobial peptide (AMP), Magainin II (Mag II) was covalently immobilized on poly(lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun fibrous membranes. The surface immobilization was characterized by X-ray Photoelectron Spectroscopy (XPS). Scanning Electron Microscopy (SEM) and Atomic Force Microscopy studies showed that the surface morphology of the fibers at micron scale was not affected by the immobilization process. The antibacterial activity of the bound Mag II was tested against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Bacterial adhesion tests, SEM and confocal analyses revealed that the attachment and survival of bacteria were inhibited on Mag II functionalized membranes. AMP immobilization strategy was introduced as a new perspective for the modulation of antibacterial properties on PLGA based materials prepared by electrospinning. - Highlights: • PLGA and PLGA/gelatin fibrous membranes were prepared by electrospinning. • Antimicrobial peptide Mag II was successfully immobilized on PLGA based membranes. • The antibacterial activity was tested against E. coli and S. aureus. • Bacterial adhesion was inhibited on Mag II functionalized membranes.

  14. The chloroplast thylakoid membrane system is a molecular conveyor belt.

    Science.gov (United States)

    Critchley, C

    1988-10-01

    Light drives photosynthesis, but paradoxically light is also the most variable environmental factor influencing photosynthesis both qualitatively and quantitatively. The photosynthetic apparatus of higher plants is adaptable in the extreme, as exemplified by its capacity for acclimation to very bright sunny or deeply shaded conditions. It can also respond to rapid changes in light such as sunflecks. In this paper I offer a model that i) explains the thylakoid membrane organisation into grana stacks and stroma lamellae, ii) proposes a role for rapid D1 protein turnover and LHCII phosphorylation, and iii) suggests a mechanism for photoinhibition. I argue that the photosynthetic membrane system is dynamic in three dimensions, so much so that, in the light, it is in constant motion and operates in a manner somewhat analogous to a conveyor belt. D1 protein degradation is proposed to be the motor that drives this system. Photoinhibition is suggested to be due to the arrest of D1 protein turnover.

  15. Sun and Shade leaves, SIF, and Photosynthetic Capacity

    Science.gov (United States)

    Berry, J. A.; Badgley, G.

    2016-12-01

    Recent advances in retrieval of solar induced chlorophyll fluorescence (SIF) have opened up new possibilities for remote sensing of canopy physiology and structure. To date most of the emphasis has been placed on SIF as an indicator of stress and photosynthetic capacity. However, it is clear that canopy structure can also have an influence. To this point, simulations of SIF in land surface models tend to under predict observed variation in SIF. Also, large, systematic differences in SIF from different canopy types seem to correlate well with the photosynthetic capacity of these canopies. SIF emissions from pampered crops can be several-fold that from evergreen, needle-leaf forests. Yet, these may have similar vegetation indices and absorb a similar fraction of incident PAR. SIF photons produced in a conifer canopy do have a lower probability of escaping its dense, clumped foliage. However, this does not explain the correlated differences in photosynthetic rate and SIF. It is useful, in this regard, to consider the separate contributions of sun and shade leaves to the SIF emitted by a canopy. Sun leaves tend to be displayed to intercept the direct solar beam, and these highly illuminated leaves are often visible from above the canopy. Sun leaves produce more SIF and a large fraction of it escapes. Therefore, the intensity of SIF may be a sensitive indicator of the partitioning of absorbed PAR to sun and shade leaves. Many models account tor the different photosynthetic capacity of sun and shade leaves in calculating canopy responses. However, the fraction of leaves in each category is usually parameterized by an assumed leaf angle distribution (e.g. spherical). In reality, the sun/shade fraction can vary over a wide range, and it has been difficult to measure. SIF and possibly near-IR reflectance of canopies can be used to specify this key parameter with obvious importance to understanding photosynthetic rate.

  16. Photosynthetic carbon metabolism in the submerged aquatic angiosperm Scirpus subterminalis

    Energy Technology Data Exchange (ETDEWEB)

    Beer, S; Wetzel, R G

    1981-01-01

    Scirpus subterminalis Torr., a submerged angiosperm abundant in many hardwater lakes of the Great Lakes region, was investigated for various photosynthetic carbon fixation properties in relation to available inorganic carbon and levels of carbon fixing enzymes. Photosynthetic experiments were CO/sub 2/ and HCO/sub 3//sup -/ were supplied at various concentrations showed that Scirpus was able to utilize HCO/sub 3//sup -/ at those concentrations close to natural conditions. However, when CO/sub 2/ concentrations were increased above ambient, photosynthetic rates increased markedly. It was concluded that the photosynthetic potential of this plant in many natural situations may be limited by inorganic carbon uptake in the light. Phosphoenolpyruvate carboxylase (PEPcase)/ribulose-1,5-bisphosphate carboxylase (ruBPcase) ratios of the leaves varied between 0.5 and 0.9 depending on substrate concentration during assay. The significance of PEP-mediated carbon fixation of Scirpus (basically a C/sub 3/ plant) in the dark was investigated. Malate accumulated in the leaves during the dark period of a 24-h cycle and malate levels decreased significantly during the following light period. The accumulation was not due to transport of malate from the roots. Carbon uptake rates in the dark by the leaves of Scirpus were lower than malate accumulation rates. Therefore, part of the malate was likely derived from respired CO/sub 2/. Carbon uptake rates in the light were much higher than malate turnover rates. It was estimated that carbon fixation via malate could contribute up to 12% to net photosynthetic rates. The ecological significance of this type of metabolism in submerged aquatics is discussed.

  17. Protection of the photosynthetic apparatus from extreme dehydration and oxidative stress in seedlings of transgenic tobacco.

    Directory of Open Access Journals (Sweden)

    Concepción Almoguera

    Full Text Available A genetic program that in sunflower seeds is activated by Heat Shock transcription Factor A9 (HaHSFA9 has been analyzed in transgenic tobacco seedlings. The ectopic overexpression of the HSFA9 program protected photosynthetic membranes, which resisted extreme dehydration and oxidative stress conditions. In contrast, heat acclimation of seedlings induced thermotolerance but not resistance to the harsh stress conditions employed. The HSFA9 program was found to include the expression of plastidial small Heat Shock Proteins that accumulate only at lower abundance in heat-stressed vegetative organs. Photosystem II (PSII maximum quantum yield was higher for transgenic seedlings than for non-transgenic seedlings, after either stress treatment. Furthermore, protection of both PSII and Photosystem I (PSI membrane protein complexes was observed in the transgenic seedlings, leading to their survival after the stress treatments. It was also shown that the plastidial D1 protein, a labile component of the PSII reaction center, and the PSI core protein PsaB were shielded from oxidative damage and degradation. We infer that natural expression of the HSFA9 program during embryogenesis may protect seed pro-plastids from developmental desiccation.

  18. Anoxic oscillating MBR for photosynthetic bacteria harvesting and high salinity wastewater treatment.

    Science.gov (United States)

    Qin, Lei; Liu, Qiuhua; Meng, Qin; Fan, Zheng; He, Jinzhe; Liu, Tao; Shen, Chong; Zhang, Guoliang

    2017-01-01

    In this study, photosynthetic bacteria (PSB) were first harvested by MBR with pendulum type oscillation (PTO) hollow fiber module in succession and on a large scale. Based on unique properties of PSB, PSB/MBR was successfully applied for high-salinity wastewater treatment. Compared with control PSB-MBR (CMBR), PSB/PTO-MBR exhibited more excellent organics removal, which was mainly attributed to much higher biomass production for utilization. Meanwhile, the influence of light irradiation and aeration on activity of PSB was investigated in detail. Results showed that PTO-MBR with 12h light irradiation proved to be a promising and economical alternative. The cycle of dark/light and anoxic had a positive effect on PSB cultivating. Moreover, PTO-MBR exhibited much higher flux than CMBR even if large amounts of biomass existed, which demonstrated that the strong shear stress on interface of liquid-membrane played important roles on membrane fouling reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Membrane contactors for CO2 capture processes - critical review

    Science.gov (United States)

    Nogalska, Adrianna; Trojanowska, Anna; Garcia-Valls, Ricard

    2017-07-01

    The use of membrane contactor in industrial processes is wide, and lately it started to be used in CO2 capture process mainly for gas purification or to reduce the emission. Use of the membrane contactor provides high contact surface area so the size of the absorber unit significantly decreases, which is an important factor for commercialization. The research has been caried out regarding the use of novel materials for the membrane production and absorbent solution improvements. The present review reveals the progress in membrane contactor systems for CO2 capture processes concerning solution for ceramic membrane wetting, comparison study of different polymers used for fabrication and methods of enzyme immobilization for biocomposite membrane. Also information about variety of absorbent solutions is described.

  20. An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

    Science.gov (United States)

    Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

    2015-01-01

    The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

  1. Immobilization of oxidases and their analytical applications

    International Nuclear Information System (INIS)

    Yasinzai, M.

    2007-01-01

    Immobilized enzymes are replacing their soluble counter-parts in nearly every field of application. These enzyme modifications have evolved from a research curiosity into an entire branch of Biotechnology. An immobilization method for flavin containing oxidases and their use in flow injection system is described. An electrochemical detector for H/sub 2/O/sub 2/ is assembled which is used effectively for the determination of glucose using more common glucose oxidase and the simultaneous determination of sugars. The combination of oxidases with hydrolases have been used for the determination of maltose and starch. (author)

  2. A disposal centre for immobilized nuclear waste

    International Nuclear Information System (INIS)

    1980-02-01

    This report describes a conceptual design of a disposal centre for immobilized nuclear waste. The surface facilities consist of plants for the preparation of steel cylinders containing nuclear waste immobilized in glass, shaft headframe buildings and all necessary support facilities. The underground disposal vault is located on one level at a depth of 1000 m. The waste cylinders are emplaced into boreholes in the tunnel floors. All surface and subsurface facilities are described, operations and schedules are summarized, and cost estimates and manpower requirements are given. (auth)

  3. Radiation Synthesis of Nanogel for Bioactives Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Hamzah, M. Y. [Polymer Modification Group, Malaysian Nuclear Agency, Bangi (Malaysia)

    2009-07-01

    Both hydrophilic and hydrophobic core nanogel are currently being developed for immobilization and delivery purposes in Malaysian Nuclear Agency. Hydrophilic nanogel is produced by using inverse micelles irradiation of polyethelyne glycol diacrylate (PEGDA). The hydrophobic nanogel is produced via irradiation of acrylated form of palm oil. These nanogels will be used to immobilize bio actives such as curcumin, tyhmoquinone, oryzanol and chitosan. Preliminary investigation of the nanogel size using dynamic light scattering (DLS) shows that nanogel with sizes below 100nm can be obtained. (author)

  4. Plutonium Immobilization Can Loading Conceptual Design

    International Nuclear Information System (INIS)

    Kriikku, E.

    1999-01-01

    'The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization can loading conceptual design and includes a process block diagram, process description, preliminary equipment specifications, and several can loading issues. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.'

  5. Radiation Synthesis of Nanogel for Bioactives Immobilization

    International Nuclear Information System (INIS)

    Hamzah, M.Y.

    2009-01-01

    Both hydrophilic and hydrophobic core nanogel are currently being developed for immobilization and delivery purposes in Malaysian Nuclear Agency. Hydrophilic nanogel is produced by using inverse micelles irradiation of polyethelyne glycol diacrylate (PEGDA). The hydrophobic nanogel is produced via irradiation of acrylated form of palm oil. These nanogels will be used to immobilize bio actives such as curcumin, tyhmoquinone, oryzanol and chitosan. Preliminary investigation of the nanogel size using dynamic light scattering (DLS) shows that nanogel with sizes below 100nm can be obtained. (author)

  6. Plutonium Immobilization Can Loading Conceptual Design

    Energy Technology Data Exchange (ETDEWEB)

    Kriikku, E.

    1999-05-13

    'The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization can loading conceptual design and includes a process block diagram, process description, preliminary equipment specifications, and several can loading issues. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.'

  7. Immobilization of spent resin with epoxy resin

    International Nuclear Information System (INIS)

    Gultom, O.; Suryanto; Sayogo; Ramdan

    1997-01-01

    immobilization of spent resin using epoxy resin has been conducted. The spent resin was mixtured with epoxy resin in variation of concentration, i.e., 30, 40, 50, 60, 70 weight percent of spent resin. The mixture were pour into the plastic tube, with a diameter of 40 mm and height of 40 mm. The density, compressive strength and leaching rate were respectively measured by quanta chrome, paul weber apparatus and gamma spectrometer. The results showed that the increasing of waste concentration would be decreased the compressive strength, and increased density by immobilized waste. The leaching rate of 137 Cs from waste product was not detected in experiment (author)

  8. Covalent immobilization of rabbit-antiaflatoxin-antibodies onto the poly-acrylamideacrylonitrile as well as hybrid material UREASIL and developing an optical immunosensor

    Directory of Open Access Journals (Sweden)

    Slavova M.

    2017-03-01

    Full Text Available The aim of this work is to describe a covalent immobilization of antibodies onto the poly- acrylamide-acrylonitrile or hybrid material UREASIL and creation of optical immunosensor for determination of aflatoxin Bl. For this purpose, mouse-anti-aflatoxin B1 antibodies with oxidized carbohydrate moieties were covalently immobilized on the membranes of polyacrylamide- polyacrylonitrile copolymer, as well as the hybrid material UREASIL. To determine the affinity> binding of the immobilized antibody with afatoxin Bl was used "sandwich" method. Associated with the immobilized antibody sought ingredients interact with a surplus of secondary’ signal antibodies. The described method has been developed as a model system, which can easily be applied for the determination of aflatoxins in samples of different origin. To the best of our knowledge, this is the first study to show that in the establishment of biosensor was used hybrid material UREASIL.

  9. Preparation of novel poly(vinylidene fluoride)/TiO2 photocatalysis membranes for use in direct contact membrane distillation

    Science.gov (United States)

    Li, Yukun; Dong, Shuying; Zhu, Liang

    2018-03-01

    Immobilization of TiO2 is a potential approach to obtain photocatalytic membranes that could eliminate concentration polarization in sewage disposal for direct contact membrane distillation (DCMD) process. A simple non-solvent-induced phase separation (NIPS) method was proposed to prepare poly(vinylidene fluoride) (PVDF) membrane, and the double-coating technology was further used to prepare the self-cleaning membranes with different TiO2 content. The effects of TiO2 nano-particles on membrane crystal form, morphology, porosity, pore size, pore size distribution, hydrophobicity, permeation, and photocatalytic efficiency were investigated, respectively. The flux of the prepared membranes is higher than the membrane (MS) provided by Membrane Solutions, LLC, in DCMD process. The contact angle between water and membrane could be increased 22° by introducing photocatalytic layer containing TiO2. During the photocatalytic test, 65.78-96.31% degrading rate of 15 mg/L Rhodamine B (RhB) was achieved. The relative flux of the membrane T-3 can be recovered to 0.96 in photocatalysis-membrane reactor for 8 h UV radiation. The fabricated membrane has great potential in high-salty dyeing wastewater treatment due to its high hydrophobicity and photocatalytic capability. [Figure not available: see fulltext.

  10. Preparation of Laccase Immobilized Cryogels and Usage for Decolorization

    Directory of Open Access Journals (Sweden)

    Murat Uygun

    2013-01-01

    Full Text Available Poly(methyl methacrylate-co-glycidyl methacrylate (poly(MMA-co-GMA cryogels were synthesized by radical cryopolymerization technique. Then, laccase enzyme was covalently attached to the cryogel and characterized by using swelling studies and SEM and EDX analyses. Kinetic properties and optimum conditions of the immobilized and free laccase were studied and it was found that of the immobilized laccase was lower than that of free laccase. of the immobilized laccase was increased upon immobilization. Optimum pH was found to be 4.0 for each type of laccase, while optimum temperature was shifted to the warmer region after the immobilization. It was also found that thermal stability of the immobilized laccase was higher than that of free laccase. Immobilized laccase could be used for 10 times successive reuse with no significant decrease in its activity. Also, these laccase immobilized cryogels were successfully used for the decolorization of seven different dyes.

  11. Immobilized cells of Candida rugosa possessing fumarase activity

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L.; Zhone, L.

    1980-01-01

    Immobilized cells of C. rugosa that possessed fumarase activity were prepared by different methods; the most active immobilized cells were entrapped in polyacrylamide gels. The effects of pH temperature, and divalent cations on the fumarase activity of both immobilized and native cells were the same. Mn/sup 2 +/, Mg/sup 2 +/, Ca/sup 2 +/, and Fe/sup 2 +/ did not protect the immobilized enzyme against thermal inactivation. The activity of immobilized fumarase remained constant during 91 days of storage of 4-6 degrees. The immobilized cell column was used for the continuous production of L-malic acid from 1M fumarate at 30 degrees and pH 8.5. The immobilized column operated steadily for 2 months. Half life of the immobilized fumarase at 30 degrees was 95 days.

  12. Bed Rest and Immobilization: Risk Factors for Bone Loss

    Science.gov (United States)

    ... Risk Factors for Bone Loss Bed Rest and Immobilization: Risk Factors for Bone Loss Like muscle, bone ... complications of pregnancy; and those who are experiencing immobilization of some part of the body because of ...

  13. 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.)

  14. Preparation and characterization of two types of covalently immobilized amyloglucosidase

    Directory of Open Access Journals (Sweden)

    ZORAN VUJCIC

    2005-05-01

    Full Text Available Amyloglucosidase from A. niger was covalently immobilized onto poly (GMA-co-EGDMA by the glutaraldehyde and periodate method. The immobilization of amyloglucosidase after periodate oxidation gave a preparate with the highest specific activity reported so far on similar polymers. The obtained immobilized preparates show the same pH optimum, but a higher temperature optimum compared with the soluble enzyme. The kinetic parameters for the hydrolysis of soluble starch by free and both immobilized enzymes were determined.

  15. Immobilization of Isolated Lipase From Moldy Copra (Aspergillus Oryzae)

    OpenAIRE

    Dali, Seniwati; Patong, A. B. D. Rauf; Jalaluddin, M. Noor; Pirman; Hamzah, Baharuddin

    2011-01-01

    Enzyme immobilization is a recovery technique that has been studied in several years, using support as a media to help enzyme dissolutions to the reaction substrate. Immobilization method used in this study was adsorption method, using specific lipase from Aspergillus oryzae. Lipase was partially purified from the culture supernatant of Aspergillus oryzae. Enzyme was immobilized by adsorbed on silica gel. Studies on free and immobilized lipase systems for determination of optimum pH, optimum ...

  16. Effect of Ethanol Stress on Fermentation Performance of Saccharomyces cerevisiae Cells Immobilized on Nypa fruticans Leaf Sheath Pieces

    Directory of Open Access Journals (Sweden)

    Hoang Phong Nguyen

    2015-01-01

    Full Text Available The yeast cells of Saccharomyces cerevisiae immobilized on Nypa fruticans leaf sheath pieces were tested for ethanol tolerance (0, 23.7, 47.4, 71.0 and 94.7 g/L. Increase in the initial ethanol concentration from 23.7 to 94.7 g/L decreased the average growth rate and concentration of ethanol produced by the immobilized yeast by 5.2 and 4.1 times, respectively. However, in the medium with initial ethanol concentration of 94.7 g/L, the average growth rate, glucose uptake rate and ethanol formation rate of the immobilized yeast were 3.7, 2.5 and 3.5 times, respectively, higher than those of the free yeast. The ethanol stress inhibited ethanol formation by Saccharomyces cerevisiae cells and the yeast responded to the stress by changing the fatty acid composition of cellular membrane. The adsorption of yeast cells on Nypa fruticans leaf sheath pieces of the growth medium increased the saturated fatty acid (C16:0 and C18:0 mass fraction in the cellular membrane and that improved alcoholic fermentation performance of the immobilized yeast.

  17. 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)

  18. Flow of light energy in benthic photosynthetic microbial mats

    Energy Technology Data Exchange (ETDEWEB)

    Al-Najjar, Mohammad Ahmad A.

    2010-12-15

    The work in this thesis demonstrates the assessment of the energy budget inside microbial mat ecosystems, and the factors affecting light utilization efficiency. It presents the first balanced light energy budget for benthic microbial mat ecosystems, and shows how the budget and the spatial distribution of the local photosynthetic efficiencies within the euphotic zone depend on the absorbed irradiance (Jabs). The energy budget was dominated by heat dissipation on the expense of photosynthesis. The maximum efficiency of photosynthesis was at light limiting conditions When comparing three different marine benthic photosynthetic ecosystems (originated from Abu-Dhabi, Arctic, and Exmouth Gulf in Western Australia), differences in the efficiencies were calculated. The results demonstrated that the maximum efficiency depended on mat characteristics affecting light absorption and scattering; such as, photopigments ratio and distribution, and the structural organization of the photosynthetic organisms relative to other absorbing components of the ecosystem (i.e., EPS, mineral particles, detritus, etc.). The maximum efficiency decreased with increasing light penetration depth, and increased with increasing the accessory pigments (phycocyanin and fucoxanthin)/chlorophyll ratio. Spatial heterogeneity in photosynthetic efficiency, pigment distribution, as well as light acclimation in microbial mats originating from different geographical locations was investigated. We used a combined pigment imaging approach (variable chlorophyll fluorescence and hyperspectral imaging), and fingerprinting approach. For each mat, the photosynthetic activity was proportional to the local pigment concentration in the photic zone, but not for the deeper layers and between different mats. In each mat, yield of PSII and E1/2 (light acclimation) generally decreased in parallel with depth, but the gradients in both parameters varied greatly between samples. This mismatch between pigments concentration

  19. Effects of different algaecides on the photosynthetic capacity, cell integrity and microcystin-LR release of Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shiqing [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Shao, Yisheng, E-mail: yishengshao@163.com [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); China Academy of Urban Planning and Design, Beijing 100037 (China); Gao, Naiyun [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Deng, Yang [Department of Earth and Environmental Studies, Montclair State University, Montclair NJ 07043 (United States); Qiao, Junlian; Ou, Huase; Deng, Jing [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

    2013-10-01

    Bench scale tests were conducted to study the effects of four common algaecides, including copper sulfate, hydrogen peroxide, diuron and ethyl 2-methylacetoacetate (EMA) on the photosynthetic capacity, cell integrity and microcystin-LR (MC-LR) release of Microcystis aeruginosa. The release of potassium (K{sup +}) from cell membrane during algaecide exposure was also analyzed. The three typical photosynthetic parameters, including the effective quantum yield (φ{sub e}), photosynthetic efficiency (α) and maximal electron transport rate (rETR{sub max}), were measured by a pulse amplitude modulated (PAM) fluorometry. Results showed that the photosynthetic capacity was all inhibited by the four algaecides, to different degrees, by limiting the energy capture in photosynthesis, and blocking the electron transfer chain in primary reaction. For example, at high diuron concentration (7.5 mg L{sup −1}), φ{sub e}, α and rETR{sub max} decreased from 0.46 to 0.19 (p < 0.01), from 0.20 to 0.01 (p < 0.01) μmol electrons m{sup −2} s{sup −1}/μmol photons m{sup −2} s{sup −1}, and from 160.7 to 0.1 (p < 0.001) μmol m{sup −2} s{sup −1} compared with the control group after 96 h of exposure, respectively. Furthermore, the increase of algaecide dose could lead to the cell lysis, as well as release of intracellular MC-LR that enhanced the accumulation of extracellular MC-LR. The order of MC-LR release potential for the four algaecides was CuSO{sub 4} > H{sub 2}O{sub 2} > diuron > EMA. Highlights: • PAM was used to investigate the effects of algaecides on Microcystis aeruginosa. • We estimate the release of potassium (K{sup +}) from cell membrane for cell lysis. • The risk of microcystin-LR release was evaluated after algaecides exposure. • The order of MC-LR release potential was copper sulfate > hydrogen peroxide > diuron > ethyl 2-methylacetoacetate.

  20. Membrane Curvature Induced by Aggregates of LH2s and Monomeric LH1s

    OpenAIRE

    Chandler, Danielle E.; Gumbart, James; Stack, John D.; Chipot, Christophe; Schulten, Klaus

    2009-01-01

    The photosynthetic apparatus of purple bacteria is contained within organelles called chromatophores, which form as extensions of the cytoplasmic membrane. The shape of these chromatophores can be spherical (as in Rhodobacter sphaeroides), lamellar (as in Rhodopseudomonas acidophila and Phaeospirillum molischianum), or tubular (as in certain Rb. sphaeroides mutants). Chromatophore shape is thought to be influenced by the integral membrane proteins Light Harvesting Complexes I and II (LH1 and ...

  1. Development of solid supports for electrochemical study of biomimetic membrane systems

    DEFF Research Database (Denmark)

    Mech-Dorosz, Agnieszka

    cushion directly on a gold electrode microchip and on a polyethersulfone (PES) support grafted by in situ polymerized hydrogel. Both strategies proved to be suitable for immobilization of functional bRh loaded lipo-polymersomes. Amperometric monitoring showed that the PES membrane support facilitated......Biomimetic membranes are model membrane systems used as an experimental tool to study fundamental cellular membrane physics and functionality of reconstituted membrane proteins. By exploiting the properties of biomimetic membranes resembling the functions of biological membranes, it is possible...... to construct biosensors for high-throughput screening of potential drug candidates. Among a variety of membrane model systems used for biomimetic approach, lipid bilayers in the form of black lipid membranes (BLMs) and lipo-polymersomes (vesicle structures composed of lipids and polymers), both...

  2. Computer-aided design of bromelain and papain covalent immobilization

    OpenAIRE

    Cutiño-Avila, Bessy; Gil Pradas, Dayrom; Aragón Abreu, Carlos; Fernández Marrero, Yuniel; Hernández de la Torre, Martha; Salas Sarduy, Emir; Chávez Planes, María de los Ángeles; Guisán Seijas, José Manuel; Díaz Brito, Joaquín; del Monte-Martínez, Alberto

    2014-01-01

    Enzymes as immobilized derivatives have been widely used in Food, Agrochemical, Pharmaceutical and Biotechnological industries. Protein immobilization is probably the most used technology to improve the operational stability of these molecules. Bromelain (Ananas comosus) and papain (Carica papaya) are cystein proteases extensively used as immobilized biocatalyst with several applications in therapeutics, racemic mixtures resolution, affinity chromatography and others industrial scenarios. The...

  3. Short-Term Limb Immobilization Affects Cognitive Motor Processes

    Science.gov (United States)

    Toussaint, Lucette; Meugnot, Aurore

    2013-01-01

    We examined the effects of a brief period of limb immobilization on the cognitive level of action control. A splint placed on the participants' left hand was used as a means of immobilization. We used a hand mental rotation task to investigate the immobilization-induced effects on motor imagery performance (Experiments 1 and 2) and a number mental…

  4. Immobilization of microbial cells: A promising tool for treatment of ...

    African Journals Online (AJOL)

    The review articles on cell immobilization have been published since 1980 and reflect the general interest in this topic. Immobilized microbial cells create opportunities in a wide range of sectors including environmental pollution control. Compared with suspended microorganism technology, cell immobilization shows many ...

  5. Characterization of immobilized post-carbohydrate meal salivary α ...

    African Journals Online (AJOL)

    The effect of experimental parameters like pH, temperature and substrate concentration on the activity of the immobilized post-carbohydrate meal salivary ... of immobilized post-carbohydrate meal salivary α-amylase in this study show that immobilization had no significant effect on the enzyme and compared to kinetic ...

  6. Characteristics of immobilized aminoacylase from Aspergillus oryzae on macroporous copolymers.

    Science.gov (United States)

    He, B L; Jiang, P; Qiu, Y B

    1990-01-01

    Aminoacylase from Aspergillus oryzae was adsorbed on functionallized macroporous copolymers where the enzyme showed excellent catalyzing activity and operation stability. Various factors which effect the activity of the immobilized aminoacylase such as temperature, pH and ionic strength were investigated. The continuous operation of the enzyme immobilized on macroporous copolymers was compared with that of the enzyme immobilized on DEAE-Sephadex.

  7. Immobilization: A Revolution in Traditional Brewing

    Science.gov (United States)

    Virkajärvi, Ilkka; Linko, Matti

    In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

  8. Silica gel matrix immobilized Chlorophyta hydrodictyon africanum ...

    African Journals Online (AJOL)

    Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results from sorption studies ...

  9. Isomaltulose production using free and immobilized Serratia ...

    African Journals Online (AJOL)

    André

    2016-05-18

    May 18, 2016 ... After 2 h of reaction time in shake flasks, a high production of ... immobilized cells in calcium alginate was studied in a packed bed bioreactor during seven days in a .... cell biomass was obtained from fermentation in a 6.6 L bioreactor .... carbohydrates were analyzed comparing their retention times with.

  10. Immobilization and packaging of recovered tritium

    International Nuclear Information System (INIS)

    Holtslander, W.J.; Miller, J.M.

    1982-09-01

    The evaluation of metal hydrides as a medium for immobilization of tritium is reviewed. The work demonstrated methods of preparation and examined the properties of titanium and zirconium hydride for this application. Methods of packaging the metal hydrides for transportation and recoverable storage of tritium were also examined

  11. Halloysite Clay Nanotubes for Enzyme Immobilization.

    Science.gov (United States)

    Tully, Joshua; Yendluri, Raghuvara; Lvov, Yuri

    2016-02-08

    Halloysite clay is an aluminosilicate nanotube formed by rolling flat sheets of kaolinite clay. They have a 15 nm lumen, 50-70 nm external diameter, length of 0.5-1 μm, and different inside/outside chemistry. Due to these nanoscale properties, they are used for loading, storage, and controlled release of active chemical agents, including anticorrosions, biocides, and drugs. We studied the immobilization in halloysite of laccase, glucose oxidase, and lipase. Overall, negatively charged proteins taken above their isoelectric points were mostly loaded into the positively charged tube's lumen. Typical tube loading with proteins was 6-7 wt % from which one-third was released in 5-10 h and the other two-thirds remained, providing enhanced biocatalysis in nanoconfined conditions. Immobilized lipase showed enhanced stability at acidic pH, and the optimum pH shifted to more alkaline pH. Immobilized laccase was more stable with respect to time, and immobilized glucose oxidase showed retention of enzymatic activity up to 70 °C, whereas the native sample was inactive.

  12. Immobilizing Biomolecules Near the Diffraction Limit

    DEFF Research Database (Denmark)

    Skovsen, Esben; Petersen, Maria Teresa Neves; Gennaro, Ane Kold Di

    2009-01-01

    Our group has previously shown that biomolecules containing disulfide bridges in close proximity to aromatic residues can be immobilized, through covalent bonds, onto thiol derivatized surfaces upon UV excitation of the aromatic residue(s). We have also previously shown that our new technology ca...

  13. Enzyme Engineering for In Situ Immobilization.

    Science.gov (United States)

    Rehm, Fabian B H; Chen, Shuxiong; Rehm, Bernd H A

    2016-10-14

    Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.

  14. Metal immobilization in soils using synthetic zeolites

    NARCIS (Netherlands)

    Osté, L.A.; Lexmond, T.M.; Riemsdijk, van W.H.

    2002-01-01

    In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite-type,

  15. Adsorption of metals by immobilized tannins

    Energy Technology Data Exchange (ETDEWEB)

    Santana, J L; Olivares, S; De La Rosa, D; Martinez, F; Vargas, L M [Centro de Estudios Aplicados al Desarrollo Nuclear (CEADEN), La Habana (Cuba)

    1996-05-01

    Simultaneous adsorption of thorium, europium, cerium, and neodymium by immobilized tannic was studied at different ph values. Tannic materials have excellent ability to adsorb selectively thorium at pH 5. The rest of the elements could be isolated in group at pH 7.

  16. Immobilization of Trichoderma reesei by radiation polymerization

    International Nuclear Information System (INIS)

    Zhou Ruimin; Ma Zueteh; Kaetus, Isao; Kumakura, Minoro

    1993-01-01

    Immobilization of Trichoderma reesei was carried out by radiation polymerization. It was found that the activity of fixed cells increased with increasing surface area of the carrier and was affected by the concentration of monomer tetraethylenglycol dimethacrylate and the shape of the substrate composition and structure of cotton textile fabrics. (author)

  17. Application of radiopolymerization for immobilization of enzymes

    International Nuclear Information System (INIS)

    Higa, O.Z.; Mastro, N.L. del; Castagnet, A.C.G.

    1986-01-01

    Hydrophilic glass-forming monomers were used in an application of irradiation technology for the immobilization of cellulase and cellobiase. Experiments to observe the effect of additives such as silicates and polyethylene glycol in the enzyme entrapment are reported on. In all cases, enzymatic activity was maintained for more than fifteen batch enzyme reactions. (Author) [pt

  18. Plutonium Immobilization Can Loading Preliminary Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Kriikku, E.

    1998-11-25

    This report discusses the Plutonium Immobilization can loading preliminary equipment specifications and includes a process block diagram, process description, equipment list, preliminary equipment specifications, plan and elevation sketches, and some commercial catalogs. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.

  19. Immobilization of Enzymes in Polymer Supports.

    Science.gov (United States)

    Conlon, Hugh D.; Walt, David R.

    1986-01-01

    Two experiments in which an enzyme is immobilized onto a polymeric support are described. The experiments (which also demonstrate two different polymer preparations) involve: (1) entrapping an enzyme in an acrylamide polymer; and (2) reacting the amino groups on the enzyme's (esterase) lysine residues with an activated polymer. (JN)

  20. IN SITU LEAD IMMOBILIZATION BY APATITE

    Science.gov (United States)

    Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxyapatite [Ca10(PO4)6(O...

  1. Isomaltulose production using free and immobilized Serratia ...

    African Journals Online (AJOL)

    Isomaltulose is a low cariogenic sweetener used as a substitute for sucrose in the food industry. In this study, isomaltulose production by Serratia plymuthica ATCC 15928 was performed using free and immobilized cells. Response Surface Methodology was employed to evaluate the influence of temperature, wet cell mass ...

  2. Physico-chemical characteristics of immobilized polygalacturonase ...

    African Journals Online (AJOL)

    Polygalacturonase (PG) was isolated from Aspergillus niger (A. niger) (SA6), partially purified, characterized and immobilized by entrapment using calcium alginate. The polygalacturonase showed two bands on sodium dodecyl sulfate polyacryamide gel electrophoresis (SDS-PAGE) suggesting an “endo and exo” ...

  3. Adsorption of metals by immobilized tannins

    International Nuclear Information System (INIS)

    Santana, J.L.; Olivares, S.; De La Rosa, D.; Martinez, F.; Vargas, L.M.

    1996-01-01

    Simultaneous adsorption of thorium, europium, cerium, and neodymium by immobilized tannic was studied at different ph values. Tannic materials have excellent ability to adsorb selectively thorium at pH 5. The rest of the elements could be isolated in group at pH 7

  4. The Use of Contact Mode Atomic Force Microscopy in Aqueous Medium for Structural Analysis of Spinach Photosynthetic Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Phuthong, Witchukorn; Huang, Zubin; Wittkopp, Tyler M.; Sznee, Kinga; Heinnickel, Mark L.; Dekker, Jan P.; Frese, Raoul N.; Prinz, Fritz B.; Grossman, Arthur R.

    2015-07-28

    To investigate the dynamics of photosynthetic pigment-protein complexes in vascular plants at high resolution in an aqueous environment, membrane-protruding oxygen-evolving complexes (OECs) associated with photosystem II (PSII) on spinach (Spinacia oleracea) grana membranes were examined using contact mode atomic force microscopy. This study represents, to our knowledge, the first use of atomic force microscopy to distinguish the putative large extrinsic loop of Photosystem II CP47 reaction center protein (CP47) from the putative oxygen-evolving enhancer proteins 1, 2, and 3 (PsbO, PsbP, and PsbQ) and large extrinsic loop of Photosystem II CP43 reaction center protein (CP43) in the PSII-OEC extrinsic domains of grana membranes under conditions resulting in the disordered arrangement of PSII-OEC particles. Moreover, we observed uncharacterized membrane particles that, based on their physical characteristics and electrophoretic analysis of the polypeptides associated with the grana samples, are hypothesized to be a domain of photosystem I that protrudes from the stromal face of single thylakoid bilayers. Our results are interpreted in the context of the results of others that were obtained using cryo-electron microscopy (and single particle analysis), negative staining and freeze-fracture electron microscopy, as well as previous atomic force microscopy studies.

  5. Supramolecular organization of photosynthetic membrane proteins in the chlorosome-containing bacterium Chloroflexus aurantiacus

    Czech Academy of Sciences Publication Activity Database

    Bína, David; Gardian, Zdenko; Vácha, František; Litvín, Radek

    2014-01-01

    Roč. 122, č. 1 (2014), s. 13-21 ISSN 0166-8595 R&D Projects: GA ČR GBP501/12/G055; GA ČR(CZ) GAP205/11/1164 Institutional support: RVO:60077344 Keywords : Photosynthesis * LH1 * Chlorosome * Chloroflexus aurantiacus Subject RIV: BO - Biophysics Impact factor: 3.502, year: 2014

  6. Apparatus and method for measuring single cell and sub-cellular photosynthetic efficiency

    Science.gov (United States)

    Davis, Ryan Wesley; Singh, Seema; Wu, Huawen

    2013-07-09

    Devices for measuring single cell changes in photosynthetic efficiency in algal aquaculture are disclosed that include a combination of modulated LED trans-illumination of different intensities with synchronized through objective laser illumination and confocal detection. Synchronization and intensity modulation of a dual illumination scheme were provided using a custom microcontroller for a laser beam block and constant current LED driver. Therefore, single whole cell photosynthetic efficiency, and subcellular (diffraction limited) photosynthetic efficiency measurement modes are permitted. Wide field rapid light scanning actinic illumination is provided for both by an intensity modulated 470 nm LED. For the whole cell photosynthetic efficiency measurement, the same LED provides saturating pulses for generating photosynthetic induction curves. For the subcellular photosynthetic efficiency measurement, a switched through objective 488 nm laser provides saturating pulses for generating photosynthetic induction curves. A second near IR LED is employed to generate dark adapted states in the system under study.

  7. Role of PufX protein in photosynthetic growth of Rhodobacter sphaeroides. 1. PufX is required for efficient light-driven electron transfer and photophosphorylation under anaerobic conditions.

    Science.gov (United States)

    Barz, W P; Francia, F; Venturoli, G; Melandri, B A; Verméglio, A; Oesterhelt, D

    1995-11-21

    The pufX gene is essential for photoheterotrophic growth of the purple bacterium Rhodobacter sphaeroides. In order to analyze the molecular function of the PufX membrane protein, we constructed a chromosomal pufX deletion mutant and phenotypically compared it to a pufX+ control strain and to two suppressor mutants which are able to grow photosynthetically in the absence of pufX. Using this genetic background, we confirmed that PufX is required for photoheterotrophic growth under anaerobic conditions, although all components of the photosynthetic apparatus were present in similar amounts in all strains investigated. We show that the deletion of PufX is not lethal for illuminated pufX- cells, suggesting that PufX is required for photosynthetic cell division. Since chromatophores isolated from the pufX- mutant were found to be unsealed vesicles, the role of PufX in photosynthetic energy transduction was studied in vivo. We show that PufX is essential for light-induced ATP synthesis (photophosphorylation) in anaerobically incubated cells. Measurements of absorption changes induced by a single turnover flash demonstrated that PufX is not required for electron flow through the reaction center and the cytochrome bc1 complex under anaerobic conditions. During prolonged illumination, however, PufX is essential for the generation of a sufficiently large membrane potential to allow photosynthetic growth. These in vivo results demonstrate that under anaerobic conditions PufX plays an essential role in facilitating effective interaction of the components of the photosynthetic apparatus.

  8. 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.

  9. Conversion Efficiency of Photosynthetically Active Radiation Into Acacia mearnsii Biomass

    Directory of Open Access Journals (Sweden)

    Elder Eloy

    2018-02-01

    Full Text Available ABSTRACT The objective of this experiment was to determine the conversion efficiency of intercepted photosynthetically active radiation into biomass of Acacia mearnsii De Wild. seedlings. A forest species, plastic tubes (90 cm3, and 11 evaluation periods (up to 180 days after emergence were used in this study. The leaf area index (LAI, total dry biomass (BIO, global solar radiation (GSR, cumulative intercepted photosynthetically active radiation (PARic, and conversion efficiency of radiation (εb were determined using a pyranometer (LI200X, LICOR. The value of εb in BIO seedlings of Acacia mearnsii was 7.76 g MJ-1. LAI was directly related to the efficiency of PARic, and this influenced the development, production potential and accumulation of BIO. The value of GSR flow was 11.81 MJ m-2 day-1, while the value inside the greenhouse was 6.26 MJ m-2 day-1.

  10. A theoretical approach to photosynthetically active radiation silicon sensor

    International Nuclear Information System (INIS)

    Tamasi, M.J.L.; Martínez Bogado, M.G.

    2013-01-01

    This paper presents a theoretical approach for the development of low cost radiometers to measure photosynthetically active radiation (PAR). Two alternatives are considered: a) glass optical filters attached to a silicon sensor, and b) dielectric coating on a silicon sensor. The devices proposed are based on radiometers previously developed by the Argentine National Atomic Energy Commission. The objective of this work is to adapt these low cost radiometers to construct reliable instruments for measuring PAR. The transmittance of optical filters and sensor response have been analyzed for different dielectric materials, number of layers deposited, and incidence angles. Uncertainties in thickness of layer deposition were evaluated. - Highlights: • Design of radiometers to measure photosynthetically active radiation • The study has used a filter and a Si sensor to modify spectral response. • Dielectric multilayers on glass and silicon sensor • Spectral response related to different incidence angles, materials and spectra

  11. Photosynthetic planulae and planktonic hydroids: contrasting strategies of propagule survival

    Directory of Open Access Journals (Sweden)

    Patrizia Pagliara

    2000-12-01

    Full Text Available Settlement delays can be important to prevent propagule waste when proper settling substrates are not immediately available. Under laboratory conditions, the planulae of Clytia viridicans underwent two alternative developmental patterns. Some settled on the bottom, forming a hydranth-gonotheca complex that produced up to four medusae and later either degenerated or gave rise to a hydroid colony. Other planulae settled right below the air-water interface, forming floating colonies that eventually fell to the bottom and settled. Halecium nanum released planulae with a rich population of symbiotic zooxanthellae that survived into a rearing jar for three months. After a long period of apparent quiescence (possibly fuelled by photosynthetic activities of zooxanthellae the planulae produced new colonies. Both photosynthetic planulae and settlement at the interface air-water allow a delay in the passage from a planktonic to a fully functional benthic life.

  12. Photosynthetic Energy Transfer at the Quantum/Classical Border.

    Science.gov (United States)

    Keren, Nir; Paltiel, Yossi

    2018-06-01

    Quantum mechanics diverges from the classical description of our world when very small scales or very fast processes are involved. Unlike classical mechanics, quantum effects cannot be easily related to our everyday experience and are often counterintuitive to us. Nevertheless, the dimensions and time scales of the photosynthetic energy transfer processes puts them close to the quantum/classical border, bringing them into the range of measurable quantum effects. Here we review recent advances in the field and suggest that photosynthetic processes can take advantage of the sensitivity of quantum effects to the environmental 'noise' as means of tuning exciton energy transfer efficiency. If true, this design principle could be a base for 'nontrivial' coherent wave property nano-devices. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Changes of Photosynthetic Behaviors in Kappaphycus alvarezii Infected by Epiphyte.

    Science.gov (United States)

    Pang, Tong; Liu, Jianguo; Liu, Qian; Lin, Wei

    2011-01-01

    Epiphytic filamentous algae (EFA) were noted as a serious problem to reduce the production and quality of K. alvarezii. The morphological studies revealed that the main epiphyte on K. alvarezii was Neosiphonia savatieri in China. Though the harmful effects of EFA on the production of K. alvarezii have been reported, the detailed mechanism of the N. savatieri in limiting the production of K. alvarezii has not been studied yet. The present paper studied the effects of N. savatieri infection on photosynthetic behaviors in K. alvarezii by detecting chlorophyll fluorescence transient in vivo. The results revealed that damage of oxygen-evolving complex (OEC), decrease of active reaction centers (RCs), and the plastoquinone (PQ) pool as well as significant reduction in the performance indexes (PI) of PSII were caused by the infection of N. savatieri. The influence of N. savatieri on photosynthetic activity of K. alvarezii should be one of the important reasons to reduce the production of K. alvarezii infected by N. savatieri.

  14. Non-photosynthetic plastids as hosts for metabolic engineering

    DEFF Research Database (Denmark)

    Mellor, Silas Busck; Behrendorff, James Bruce Yarnton H; Nielsen, Agnieszka Janina Zygadlo

    2018-01-01

    Using plants as hosts for production of complex, high-value compounds and therapeutic proteins has gained increasing momentum over the past decade. Recent advances in metabolic engineering techniques using synthetic biology have set the stage for production yields to become economically attractive......, but more refined design strategies are required to increase product yields without compromising development and growth of the host system. The ability of plant cells to differentiate into various tissues in combination with a high level of cellular compartmentalization represents so far the most...... in green tissues, have proven to be suitable for high yield protein and bio-compound production. Unfortunately, chloroplast manipulation often affects photosynthetic efficiency and therefore plant fitness. In this respect, plastids of non-photosynthetic tissues, which have focused metabolisms for synthesis...

  15. Quantum measurement corrections to CIDNP in photosynthetic reaction centers

    International Nuclear Information System (INIS)

    Kominis, Iannis K

    2013-01-01

    Chemically induced dynamic nuclear polarization is a signature of spin order appearing in many photosynthetic reaction centers. Such polarization, significantly enhanced above thermal equilibrium, is known to result from the nuclear spin sorting inherent in the radical pair mechanism underlying long-lived charge-separated states in photosynthetic reaction centers. We will show here that the recently understood fundamental quantum dynamics of radical-ion-pair reactions open up a new and completely unexpected pathway toward obtaining chemically induced dynamic nuclear polarization signals. The fundamental decoherence mechanism inherent in the recombination process of radical pairs is shown to produce nuclear spin polarizations of the order of 10 4 times (or more) higher than the thermal equilibrium value at the Earth's magnetic field relevant to natural photosynthesis. This opens up the possibility of a fundamentally new exploration of the biological significance of high nuclear polarizations in photosynthesis. (paper)

  16. Photosynthetic carbon reduction by seagrasses exposed to ultraviolet A radiation

    Science.gov (United States)

    1979-01-01

    The seagrasses Halophila engelmannii, Halodule wrightii, and Syringodium filiforme were examined for their intrinsic sensitivity to ultraviolet-A-UV-A and ultraviolet-B-UV-B radiation. The effect of UV-A on photosynthetically active radiation (PAR) was also determined. Ultraviolet-A and ultraviolet-B were studied with emphasis on the greater respective environmental consequence in terms of seagrass distribution and abundance. Results indicate that an intrinsic sensitivity to UV-A alone is apparent only in Halophila, while net photosynthesis in Halodule and Syringodium seems unaffected by the level of UV-A provided. The sensitivity of Halophila to UV-A in the absense of (PAR) indicates that the photosynthetic reaction does not need to be in operation for damage to occur. Other significant results are reported.

  17. BOREAS TE-9 NSA Photosynthetic Capacity and Foliage Nitrogen Data

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Dang, Qinglai; Margolis, Hank; Coyea, Marie

    2000-01-01

    The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-9 (Terrestrial Ecology) team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. This data set describes the spatial and temporal relationship between foliage nitrogen concentration and photosynthetic capacity in the canopies of black spruce, jack pine, and aspen located within the Northern Study Area (NSA). The data were collected from June to September 1994 and are useful for modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. The data are available in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  18. In Situ Blotting : A Novel Method for Direct Transfer of Native Proteins from Sectioned Tissue to Blotting Membrane

    NARCIS (Netherlands)

    Okabe, Masashi; Nyakas, Csaba; Buwalda, Bauke; Luiten, Paul G.M.

    1993-01-01

    We describe a novel technique for direct transfer of native proteins from unfixed frozen tissue sections to an immobilizing matrix, e.g., nitrocellulose, polyvinyliden difluoride, or positively charged nylon membranes. Proteins are directly blotted onto the membrane, providing optimal accessibility

  19. Enzyme Immobilization: An Overview on Methods, Support Material, and Applications of Immobilized Enzymes.

    Science.gov (United States)

    Sirisha, V L; Jain, Ankita; Jain, Amita

    Immobilized enzymes can be used in a wide range of processes. In recent years, a variety of new approaches have emerged for the immobilization of enzymes that have greater efficiency and wider usage. During the course of the last two decades, this area has rapidly expanded into a multidisciplinary field. This current study is a comprehensive review of a variety of literature produced on the different enzymes that have been immobilized on various supporting materials. These immobilized enzymes have a wide range of applications. These include applications in the sugar, fish, and wine industries, where they are used for removing organic compounds from waste water. This study also reviews their use in sophisticated biosensors for metabolite control and in situ measurements of environmental pollutants. Immobilized enzymes also find significant application in drug metabolism, biodiesel and antibiotic production, bioremediation, and the food industry. The widespread usage of immobilized enzymes is largely due to the fact that they are cheaper, environment friendly, and much easier to use when compared to equivalent technologies. © 2016 Elsevier Inc. All rights reserved.

  20. Enhanced Practical Photosynthetic CO2 Mitigation. Quarterly Technical Report

    International Nuclear Information System (INIS)

    Gregory Kremer; David J. Bayless; Morgan Vis; Michael Prudich; Keith Cooksey; Jeff Muhs

    2005-01-01

    This report highlights significant achievements in the Enhanced Practical Photosynthetic CO 2 Mitigation Project during the ending 12/31/2004. Specific results and accomplishments for the program include review of pilot scale testing and design of a new bioreactor. Testing confirmed that algae can be grown in a sustainable fashion in the pilot bioreactor, even with intermittent availability of sunlight. The pilot-scale tests indicated that algal growth rate followed photon delivery during productivity testing