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Sample records for pixe-aided immobilization study

  1. A comparative study of free and immobilized soybean and horseradish peroxidases for 4-chlorophenol removal: protective effects of immobilization.

    PubMed

    Bódalo, Antonio; Bastida, Josefa; Máximo, M Fuensanta; Montiel, M Claudia; Gómez, María; Murcia, M Dolores

    2008-10-01

    Horseradish peroxidase (HRP) and soybean peroxidase (SBP) were covalently immobilized onto aldehyde glass through their amine groups. The activity yield and the protein content for the immobilized SBP were higher than for the immobilized HRP. When free and immobilized peroxidases were tested for their ability to remove 4-chlorophenol from aqueous solutions, the removal percentages were higher with immobilized HRP than with free HRP, whereas immobilized SBP needs more enzyme to reach the same conversion than free enzyme. In the present paper the two immobilized derivatives are compared. It was found that at an immobilized enzyme concentration in the reactor of 15 mg l(-1), SBP removed 5% more of 4-chlorophenol than HRP, and that a shorter treatment was necessary. Since immobilized SBP was less susceptible to inactivation than HRP and provided higher 4-chlorophenol elimination, this derivative was chosen for further inactivation studies. The protective effect of the immobilization against the enzyme inactivation by hydrogen peroxide was demonstrated.

  2. Production, immobilization and thermodynamic studies of free and immobilized Aspergillus awamori amylase.

    PubMed

    Karam, Eman A; Abdel Wahab, Walaa A; Saleh, Shireen A A; Hassan, Mohamed E; Kansoh, Amany L; Esawy, Mona A

    2017-09-01

    Enzyme cost, stability and its thermodynamic characteristics are the main criteria for industrial use. In this study, Aspergillus awamori amylase was constitutively produced using various agro-industrial wastes. Olive oil cake gave the highest activity (230U/g). The amylase was partially purified to 2.81-fold purification. Immobilization was achieved using different carriers by covalent binding. The novel carrier Ca(+2) alginate (Alg) starch (St)/polyethyleneimine (PEI)/glutaraldehyde (GA), showed the highest operational stability and was selected for further studies. The optimum temperature for the free and immobilized form was 50°C and 55-60°C, respectively. The immobilization process had a major role in improving enzyme thermal stability. In comparison to free enzyme, the immobilized form showed the highest optimum temperature, activation energy (Ea) and deactivation rate constants (kd). Also, t1/2, D-values (decimal reduction time), change in enthalpy (ΔH° kJmol(-1)), and Gibbs free energy (ΔG°) increased and was higher than the native enzyme within 50-80°C. The magnitude of negative value of entropy (ΔS° kJmol(-1)) for immobilized enzyme was negative for the free and immobilized enzymes revealing that native form of enzyme was in more ordered state. Km and Vmax values were slightly affected by the temperature variations 40-70°C. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Silica-encapsulated magnetic nanoparticles: enzyme immobilization and cytotoxic study.

    PubMed

    Ashtari, Khadijeh; Khajeh, Khosro; Fasihi, Javad; Ashtari, Parviz; Ramazani, Ali; Vali, Hojatollah

    2012-05-01

    Silica-encapsulated magnetic nanoparticles (MNPs) were prepared via microemulsion method. The products were characterized by high resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectrum (EDS). MNPs with no observed cytotoxic activity against human lung carcinoma cell and brine shrimp lethality were used as suitable support for glucose oxidase (GOD) immobilization. Binding of GOD onto the support was confirmed by the FTIR spectra. The amount of immobilized GODs was 95 mg/g. Storage stability study showed that the immobilized GOD retained 98% of its initial activity after 45 days and 90% of the activity was also remained after 12 repeated uses. Considerable enhancements in thermal stabilities were observed for the immobilized GOD at elevated temperatures up to 80°C and the activity of immobilized enzyme was less sensitive to pH changes in solution.

  4. Urokinase immobilized on medical polymeric materials: fundamental and clinical studies.

    PubMed

    Ohshiro, T; Kosaki, G

    1980-02-01

    One of the methods of preparing an antithrombogenic material is to immobilize a fibrinolytic enzyme on the surface of a carrier. The clinical trial of such a material must be subject to not only a basic study on the quality of a carrier, the technique of immobilization, and the method of disinfection, but also an in vivo study on its antithrombotic effect. Reported herein is the evaluation of the fibrinolytic ability, at fundamental and clinical levels, of the urokinase that was immobilized on the surface of various polymeric materials. The results were favorable.

  5. Surface studies of albumin immobilized onto PE and PVC films.

    PubMed

    de Queiroz, A A; Barrak, E R; Gil, H A; Higa, O Z

    1997-01-01

    The aim of this study is to evaluate the thrombogenic behaviour of the low density polyethylene and poly(vinyl chloride) modified by radiation-grafting technique. After copolymerization with acrylic acid by gamma-rays from a 60Co source, BSA was immobilized onto functionalized graft copolymers. The biological interaction between these materials and blood was studies by in vitro methods. The BSA immobilization effectively suppressed the adhesion and activation of platelets when it contacted whole blood.

  6. Immobilized enzyme studies in a microscale bioreactor.

    PubMed

    Jones, Francis; Forrest, Scott; Palmer, Jim; Lu, Zonghuan; Elmore, John; Elmore, Bill B

    2004-01-01

    Novel microreactors with immobilized enzymes were fabricated using both silicon and polymer-based microfabrication techniques. The effectiveness of these reactors was examined along with their behavior over time. Urease enzyme was successfully incorporated into microchannels of a polymeric matrix of polydimethylsiloxane and through layer-bylayer self-assembly techniques onto silicon. The fabricated microchannels had cross-sectional dimensions ranging from tens to hundreds of micrometers in width and height. The experimental results for continuous-flow microreactors are reported for the conversion of urea to ammonia by urease enzyme. Urea conversions of >90% were observed.

  7. Influence of immobilization strategies on biosensing response characteristics: A comparative study.

    PubMed

    Kaur, Gurpreet; Saha, Shibu; Tomar, Monika; Gupta, Vinay

    2016-01-01

    The immobilization technique plays an important role in fabrication of a biosensor. NiO based cholesterol biosensor has been used to study the effect of various immobilization techniques on the biosensing response characteristics. The biosensors were fabricated by immobilizing cholesterol oxidase on NiO thin films by three different immobilization techniques viz. physisorption, cross-linking and covalent binding. The study reveals a strong dependence of biosensing response on corresponding immobilization technique. The biosensor based on immobilization by covalent bonding shows superior response characteristics as compared to others owing to its zero length. The results highlight the significance of immobilization technique for biosensor fabrication.

  8. Preliminary studies on immobilization of lipase using chicken eggshell

    NASA Astrophysics Data System (ADS)

    Salleh, S.; Serri, N. A.; Hena, S.; Tajarudin, H. A.

    2016-06-01

    A few advantages of enzyme immobilization are reusability of expensive enzyme, improvement of stability and activity compared to crude enzyme. Various organic components can be used as carrier for enzyme immobilization such as chicken eggshell. It can be used as a carrier for immobilization as its mineral component mostly contains of calcium carbonate. In the present study, Tributyrin method was used to test enzyme activity of Rhizomucour Miehei, Candida Antarctica and Candida Rugosa. Rhizomucour Miehei shows the highest enzyme activity (360.8 mol/min/mL lipase) and was used in further experiment. Experiment was continued to study incubation time for lipase immobilization on eggshell (1-4 hours) and reaction time of esterification of sugar ester (0-72 hours). Two hours incubation time for lipase immobilization was observed and gives the highest yield of sugar ester (78.13%). Fructose and stearic acid as substrate was used for the production of sugar ester. The highest percentage of sugar ester production was shown at 36 hours of reaction time.

  9. In situ ellipsometric study of surface immobilization of flagellar filaments

    NASA Astrophysics Data System (ADS)

    Kurunczi, S.; Németh, A.; Hülber, T.; Kozma, P.; Petrik, P.; Jankovics, H.; Sebestyén, A.; Vonderviszt, F.; Fried, M.; Bársony, I.

    2010-10-01

    Protein filaments composed of thousands of subunits are promising candidates as sensing elements in biosensors. In this work in situ spectroscopic ellipsometry is applied to monitor the surface immobilization of flagellar filaments. This study is the first step towards the development of layers of filamentous receptors for sensor applications. Surface activation is performed using silanization and a subsequent glutaraldehyde crosslinking. Structure of the flagellar filament layers immobilized on activated and non-activated Si wafer substrates is determined using a two-layer effective medium model that accounted for the vertical density distribution of flagellar filaments with lengths of 300-1500 nm bound to the surface. The formation of the first interface layer can be explained by the multipoint covalent attachment of the filaments, while the second layer is mainly composed of tail pinned filaments floating upwards with the free parts. As confirmed by atomic force microscopy, covalent immobilization resulted in an increased surface density compared to absorption.

  10. Study on algae removal by immobilized biosystem on sponge

    NASA Astrophysics Data System (ADS)

    Pei, Haiyan; Hu, Wenrong

    2006-10-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively. The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  11. Stability studies of immobilized lipase on rice husk and eggshell membrane

    NASA Astrophysics Data System (ADS)

    Abdulla, R.; Sanny, S. A.; Derman, E.

    2017-06-01

    Lipase immobilization for biodiesel production is gaining importance day by day. In this study, lipase from Burkholderia cepacia was immobilized on activated support materials namely rice husk and egg shell membrane. Both rice husk and eggshell membrane are natural wastes that holds a lot of potential as immobilization matrix. Rice husk and eggshell membrane were activated with glutaraldehyde. Lipase was immobilized on the glutaraldehyde-activated support material through adsorption. Immobilization efficiency together with enzyme activity was observed to choose the highest enzyme loading for further stability studies. Immobilization efficiency of lipase on rice husk was 81 as compared to an immobilization efficiency of 87 on eggshell membrane. Immobilized lipase on eggshell membrane exhibited higher enzyme activity as compared to immobilized lipase on rice husk. Eggshell membrane also reported higher stability than rice husk as immobilization matrix. Both types of immobilized lipase retatined its activity after ten cycles of reuse. In short, eggshell membrane showed to be a better immobilization platform for lipase as compared to rice husk. However, with further improvement in technique of immobilization, the stability of both types of immobilized lipase can be improved to a greater extent.

  12. Subsurface Immobilization of Plutonium: Experimental and Model Validation Studies

    SciTech Connect

    Rittmann, Bruce E; Deo, Randhir P; Reed, Donald T

    2008-08-13

    We conducted a coordinated experimental and modeling study centered on the interaction of Shewanella alga BrY (S. alga) with plutonium species and phases. Plutonium is the key contaminant of concern at several DOE sites that are being addressed by the overall ERSP program. The over-arching goal of this research was to understand the long-term stability of bio-precipitated immobilized plutonium phases under changing redox conditions in biologically active systems. To initiate the process of plutonium immobilization, a side-by-side comparison of the bioreduction of uranyl and plutonyl species was conducted with S. alga. Uranyl was reduced in our system, consistent with literature reports, but we noted coupling between abiotic and biotic processes and observed that non-reductive pathways to precipitation typically exist. Additionally, a key role of biogenic Fe2+, which is known to reduce uranyl at low pH, is suggested. In contrast, residual organics, present in biologically active systems, reduce Pu(VI) species to Pu(V) species at near-neutral pH. The predominance of relatively weak complexes of PuO2+ is an important difference in how the uranyl and plutonyl species interacted with S. alga. Pu(V) also led to increased toxicity towards S. alga and is also more easily reduced by microbial activity. Biogenic Fe2+, produced by S. alga when Fe3+ is present as an electron acceptor, also played a key role in understanding redox controls and pathways in this system. Overall, the bioreduction of plutonyl was observed under anaerobic conditions, which favor its immobilization in the subsurface. Understanding the mechanism by which redox control is established in biologically active systems is a key aspect of remediation and immobilization strategies for actinides when they are present as subsurface contaminants.

  13. Effects of the immobilization supports on the catalytic properties of immobilized mushroom tyrosinase: a comparative study using several substrates.

    PubMed

    Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Cánovas, Francisco; García-Ruiz, Pedro Antonio

    2007-09-30

    Mushroom tyrosinase was immobilized from an extract onto glass beads covered with one of the following compounds: the crosslinked totally cinnamoylated derivatives of glycerine, D-sorbitol, D-manitol, 1,2-O-isopropylidene-alpha-D-glucofuranose, D-glucuronic acid, D-gulonic acid, sucrose, D-glucosone, D-arabinose, D-fructose, D-glucose, ethyl-D-glucopyranoside, inuline, dextrine, dextrane or starch, or the partially cinnamoylated derivative 3,5,6-tricinnamoyl-D-glucofuranose which was obtained by the acid hydrolysis of 1,2-O-isopropylidene-alpha-d-glucofuranose. The enzyme was immobilized by direct adsorption onto the support and the quantity of tyrosinase immobilized was found to increase with the hydrophobicity of the supports. The kinetic constants of immobilized tyrosinase acting on the substrates, 4-tert-butylcatechol, dopamine and DL-dopa, were studied. When immobilized tyrosinase acted on 4-tert-butylcatechol, the values of K(m)(app) were lower than these obtained for tyrosinase in solution while, when dopamine and DL-dopa were used, the K(m)(app) were higher. The order of the substrates as regards their ionizable groups, DL-dopa (two ionizable groups)>dopamine (one ionizable group)>4-tert-butylcatechol (no ionizable group) coincided with the order of the K(m)(app) values shown by tyrosinase immobilized on the hydrophobic supports, and was the inverse of that observed for tyrosinase in solution. The K(m)(app) values of immobilized tyrosinase were in all cases higher than those of soluble tyrosinase and depended on the nature of the support and the hydrophobicity of the substrate, meaning that it is possible to design supports with different degrees of selectivity towards a mixture of enzyme substrates in the reaction medium.

  14. Laccase immobilization over multi-walled carbon nanotubes: Kinetic, thermodynamic and stability studies.

    PubMed

    Tavares, Ana P M; Silva, Cláudia G; Dražić, Goran; Silva, Adrián M T; Loureiro, José M; Faria, Joaquim L

    2015-09-15

    The biocatalytic performance of immobilized enzyme systems depends mostly on the intrinsic properties of both biomolecule and support, immobilization technique and immobilization conditions. Multi-walled carbon nanotubes (MWCNTs) possess unique features for enzyme immobilization by adsorption. Enhanced catalytic activity and stability can be achieved by optimization of the immobilization conditions and by investigating the effect of operational parameters. Laccase was immobilized over MWCNTs by adsorption. The hybrid material was characterized by Fourier transformed infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM, respectively). The effect of different operational conditions (contact time, enzyme concentration and pH) on laccase immobilization was investigated. Optimized conditions were used for thermal stability, kinetic, and storage and operational stability studies. The optimal immobilization conditions for a laccase concentration of 3.75μL/mL were a pH of 9.0 and a contact time of 30min (522 Ulac/gcarrier). A decrease in the thermal stability of laccase was observed after immobilization. Changes in ΔS and ΔH of deactivation were found for the immobilized enzyme. The Michaelis-Menten kinetic constant was higher for laccase/MWCNT system than for free laccase. Immobilized laccase maintained (or even increased) its catalytic performance up to nine cycles of utilization and revealed long-term storage stability. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Studies on the thermal inactivation of immobilized enzymes

    SciTech Connect

    Ulbrich, R.; Schellenberger, A.; Damerau, W.

    1986-04-01

    The thermal inactivation of a great number of immobilized enzymes shows a biphasic kinetics, which distinctly differs from the first-order inactivation kinetics of the corresponding soluble enzymes. As shown for ..cap alpha..-amylase, chymotrypsin, and trypsin covalently bound to silica, polystyrene, or polyacrylamide, the dependence of the remaining activities on the heating time can be well described by the sum of two exponential terms. To interpret this mathematical model function, the catalytic properties of immobilized enzymes (number of active sites in silica-bound trypsin, Km and Ea values in silica-bound ..cap alpha..-amylase and chymotrypsin) at different stages of inactivation and the influence of various factors (coupling conditions, addition of denaturants or stabilizers, etc.) on the thermal inactivation of silica-bound ..cap alpha..-amylase were studied. Furthermore, conformational alterations in the thermal denaturation of spin-labeled soluble and silica-bound ..beta..-amylase were compared by electron spin resonance (ESR) studies. The results suggest that the biphasic inactivation kinetics reflects two different pathways according to which catalytically identical enzyme molecules are predominantly inactivated. 45 references.

  16. Adhesion Peptide Immobilization on Electrospun Polymers: a Photoelectron Spectroscopy Study

    SciTech Connect

    Iucci, G.; Polzonetti, G.; Ghezzo, F.; Modesti, M.; Roso, M.; Dettin, M.

    2010-06-02

    The immobilization of an oligopeptide, mimicking the adhesion sequence of fibronectin, on the surface of polymer films prepared by electrospinning was investigated by XPS spectroscopy. Films of polycaprolactone (PCL) and poly(l-lactide-caprolactone)[P(LLA-CL)] were prepared by electrospinning onto aluminium substrates. A modified adhesion peptide containing a photoreactive group was immobilized on the surface of the polymer nanofibers by incubation in peptide solution and subsequent UV irradiation. XPS analysis yield evidence of successful peptide immobilization on the polymer surface; the amount of immobilized peptide increases with the concentration of the mother solution.

  17. Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads.

    PubMed

    Başak, Esra; Aydemir, Tülin; Dinçer, Ayşe; Becerik, Seda Çınar

    2013-12-01

    Catalase was immobilized on chitosan and modified chitosan. Studies were carried out on free-immobilized catalase concerning the determination of optimum temperature, pH, thermal, storage stability, reusability, and kinetic parameters. Optimum temperature and pH for free catalase and catalase immobilized were found as 35°C and 7.0, respectively. After 100 times of repeated tests, the immobilized catalases on chitosan-clay and magnetic chitosan maintain over 50% and 60% of the original activity, respectively. The ease of catalase immobilization on low-cost matrices and good stability upon immobilization in the present study make it a suitable product for further use in the food industry.

  18. [The study of photochemical immobilization of urease on polyether sulfone film surface].

    PubMed

    Li, Sai; Fu, Hao; Luo, Xianglin; Wan, Changxiu; Zhong, Yinping

    2002-01-01

    A new method of using photoactivable ester with azido group was described to immobilize urease on polyether sulfone(PES) film surface. The effects of photoactive enzyme concentration, temperature, pH, irradiation time on the activity of immobilized urease were investigated. Reused times and storage stability were also studied. The results showed that the surface concentration of urease immobilized on PES surface was about 0.33 mg/cm2. When the irradiation time was 5 minutes, the relative activity of immobilized urease was the highest and the activity increased with the increase of the concentration of photoactive urease solution. The optimum pH and temperature of immobilized urease were 7 and 50 degrees C respectively. The relative activity of immobilized urease was stable (50%) after 12 times reused at 50 degrees C.

  19. Dual growth factor-immobilized microspheres for tissue reinnervation: in vitro and preliminary in vivo studies.

    PubMed

    Kim, Tae Ho; Oh, Se Heang; An, Dan Bi; Lee, Ji Youl; Lee, Jin Ho

    2015-01-01

    Growth factors (GFs) (basic fibroblast growth factor (bFGF) and/or nerve growth factor (NGF))-immobilized polycaprolactone (PCL)/Pluronic F127 microspheres were prepared using an isolated particulate-melting method and the sequential binding of heparin and GFs onto the microspheres. The GFs immobilized on the microspheres were released in a sustained manner over 28 days, regardless of GF type. From the in vitro culture of muscle-derived stem cells, it was observed that the NGF-immobilized microspheres induced more neurogenic differentiation than the bFGF-immobilized microspheres, as evidenced by a quantitative real-time polymerase chain reaction using specific neurogenic markers (Nestin, GFAP, β-tubulin, and MAP2) and Western blot (Nestin and β-tubulin) analyses. The dual bFGF/NGF-immobilized microspheres showed better neurogenic differentiation than the microspheres immobilized with single bFGF or NGF. From the preliminary animal study, the dual bFGF/NGF-immobilized microsphere group also showed effective nerve regeneration, as evaluated by immunocytochemistry using a marker - β-tubulin. The dual bFGF/NGF-immobilized PCL/Pluronic F127 microspheres may be a promising candidate for nerve regeneration in certain target tissues (i.e. muscles) leading to sufficient reinnervation.

  20. Immobilization of tryptophan hydroxylase by immune adsorption: a method to study regulation of catalytic activity.

    PubMed

    Johansen, P A; Jennings, I; Cotton, R G; Kuhn, D M

    1992-12-01

    Tryptophan hydroxylase (TPH) can be immobilized by adsorption to Pansorbin after binding to the monoclonal antibody PH8. This method yields recoveries of 35%-40% of total TPH activity in crude extracts and can be completed in 1.5 h. The immobilized form of TPH retains the essential kinetic properties of the native enzyme and responds to activators (phosphatidylserine) and inhibitors (catechol compounds) as does the native enzyme. Unlike TPH in brain extracts, immobilized TPH is not activated by calcium-stimulated phosphorylating conditions. When extracts from which TPH has been precipitated, and which contain calcium-calmodulin dependent protein kinase are added to immobilized TPH, the activation of TPH is restored. This method of immobilization of TPH via immune-adsorption allows for the highly specific and rapid preparation of affinity purified TPH that can be used to study the regulation of this enzyme by a variety of effectors, especially protein kinases.

  1. Immobilized E. coli alkaline phosphatase. Its properties, stability, and utility in studying the dephosphorylation of proteins.

    PubMed

    Basheeruddin, K; Rothman, V; Margolis, S

    1985-04-01

    We have immobilized E. coli alkaline phosphatase (EC 3.1.3.1) by linking it covalently to sepharose 4B. This preparation has several advantages over the soluble enzyme. The immobilized enzyme is easily separable from other constituents in incubation mixtures. The immobilized enzyme can be reused repeatedly and is more stable than the soluble enzyme to heat treatment in the presence of 10 mM Mg2+. The insoluble and soluble phosphatases removed 75 and 77%, respectively, of the inorganic phosphorus from casein. The immobilized enzyme inactivated two enzymes believed to be active in the phosphorylated state, acyl-CoA:cholesterol acyltransferase (ACAT) by 39% and NADPH-cytochrome P-450 reductase by 89%. The utility of immobilized alkaline phosphatase for studying the phosphorylation and dephosphorylation of soluble or membrane-bound enzymes and proteins is discussed.

  2. Effects of postoperative immobilization on the reconstructed anterior cruciate ligament. An experimental study in rabbits.

    PubMed

    Muneta, T; Yamamoto, H; Takakuda, K; Sakai, H; Furuya, K

    1993-01-01

    To investigate the effects of postoperative immobilization and limited motion on reconstructed anterior cruciate ligaments, 28 rabbits received an anterior cruciate ligament reconstruction using autogenous Achilles tendon and were then divided into three groups: fully immobilized, 4 weeks immobilized, and limited motion. Two rabbits from each group were evaluated macroscopically, histologically and microangiographically at 4-week intervals until 12 weeks postoperatively. An additional six rabbits in the 4 weeks immobilized and limited motion groups were studied biomechanically at 12 weeks postoperatively. Macroscopically, both immobilized groups showed more proliferation of the infrapatellar fat pad, which was adherent to the reconstructed anterior cruciate ligament. Histology revealed more rapid regeneration of reconstructed anterior cruciate ligaments in the limited motion group, with no findings of necrosis in the mid-substance. Microangiography indicated faster normalization of vascularity in the limited motion group. The biomechanical study showed no significant difference in laxity between the 4 weeks immobilized and limited motion groups. The graft stiffness and maximum load to failure were greater for the limited motion group, although the increase was not statistically significant. The histologic and microangiographic results from the limited number of animals in this study support limited postoperative motion in the anterior cruciate ligament reconstructed knee. However, there were no differences in terms of the biomechanical parameters at 12 weeks postoperatively between the immobilized and limited motion treatment modes.

  3. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    SciTech Connect

    Stanger, Keith James

    2003-01-01

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-α-acetamidocinnamate (MAC), has the illustrated structure as established by 31P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]4, [Rh(COD)2]+BF4-, [Rh(COD)Cl]2, and RhCl3• 3H2O, adsorbed on SiO2 are optimally activated for toluene hydrogenation by pretreatment with H2 at 200 C. The same complexes on Pd-SiO2 are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH2)3s-]Re(O)(Me)(PPh3) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

  4. An XPS study on the covalent immobilization of adhesion peptides on a glass surface

    NASA Astrophysics Data System (ADS)

    Iucci, G.; Battocchio, C.; Dettin, M.; Ghezzo, F.; Polzonetti, G.

    2010-11-01

    Covalent attachment of adhesive peptides to biomaterials surfaces can result in the formation of a bioactive and biomimetic surface. We have demonstrated that titanium surfaces grafted with adhesion peptides, reproducing sequences of fibronectin and vitronectin, can increase osteoblast adhesion compared to non-treated surfaces. We now extend our investigation to peptide immobilization on glass for studying human osteoblast adhesion and spreading. Silanization was used to anchor adhesion peptides to the glass surface through a selective or a non-selective immobilization. Investigated samples were analysed by XPS spectroscopy. Comparison between the results obtained using two different peptides and applying selective and non-selective immobilization will be discussed.

  5. Silica-Immobilized Enzyme Reactors; Application to Cholinesterase-Inhibition Studies

    DTIC Science & Technology

    2006-03-01

    AFRL-ML-TY-TP-2006-4575 PREPRINT SILICA-IMMOBILIZED ENZYME REACTORS; APPLICATON TO CHOLINESTERASE- INHIBITION STUDIES Heather R...P K 1 g i ( u a i a i e v b c a m p l 1 d Journal of Chromatography B, 843 (2006) 310–316 Silica-immobilized enzyme reactors; application to...method is reported for the preparation of an immobilized enzyme reactor (IMER) using silica-encapsulated equine utyrylcholinesterase (BuChE) as a model

  6. Comparative study of random and oriented antibody immobilization techniques on the binding capacity of immunosensor.

    PubMed

    Kausaite-Minkstimiene, A; Ramanaviciene, A; Kirlyte, J; Ramanavicius, A

    2010-08-01

    A comparative study of four different antibody immobilization techniques that are suitable for modification of surface plasmon resonance (SPR) chip (SPR-chip) is reported. Antibodies against human growth hormone (anti-HGH) were used as the model system. The evaluated SPR-chip modification techniques were (i) random immobilization of intact anti-HGH (intact-anti-HGH) via self-assembled monolayer (SAM) based on 11-mercaptoundecanoic acid (MUA); (ii) random immobilization of intact-anti-HGH within carboxymethyl dextran (CMD) hydrogel by direct covalent amine coupling technique; (iii) oriented coupling of intact-anti-HGH via Fc-fragment to protein-G layer assembled on SAM consisting of MUA (MUA/pG); (iv) oriented immobilization of fragmented anti-HGH antibodies (frag-anti-HGH) via their native thiol-groups directly coupled to the gold. To liberate these thiol groups, the intact-anti-HGH was chemically "divided" into two frag-anti-HGH fragments by chemical reduction with 2-mercaptoethylamine (2-MEA). Optimal concentration of 2-MEA for preparation of anti-HGH was 15 mM. The surface concentration of immobilized antibodies and the antigen binding capacity for all four differently modified SPR-chips was evaluated and compared. The maximum surface concentration of immobilized intact-anti-HGH was obtained by immobilizing the antibody within CMD-hydrogel. The maximal antigen binding capacity was obtained by SPR-chip based on intact-anti-HGH immobilized via MUA/pG. The immobilization based on application of frag-anti-HGH was found to be the most suitable for design of SPR-immunosensor for HGH detection, due to its sufficient antigen binding capacity, simplicity, and low cost in respect to the currently evaluated techniques.

  7. Enzyme-immobilized reactors for rapid and efficient sample preparation in MS-based proteomic studies.

    PubMed

    Yamaguchi, Hiroshi; Miyazaki, Masaya

    2013-02-01

    Proteolysis is a key step in proteomic studies integrated with MS analysis but the conventional method of in-solution digestion is limited by time-consuming procedures and low sensitivity. Furthermore, obtaining reliable peptide maps and meaningful sequence data using MS analysis requires not only the separation of the digested peptides but also strictly defined proteolysis conditions. Recently, various immobilized-enzyme reactors have been developed for highly efficient proteolysis in MS-based proteomic analysis. This review focuses on the proteolysis step using protease-immobilized reactors and rapid analysis of protein sequences. We describe the preparation of enzyme reactors by several techniques and protein digestion under unusual conditions. Analysis of posttranslational modifications by enzyme reactors prepared using our immobilization method is presented as a model application. Analysis systems using immobilized-enzyme reactors are expected to become useful tools for proteomic studies and diverse applications in biotechnology.

  8. Functionalized graphene sheets as immobilization matrix for Fenugreek β-amylase: enzyme kinetics and stability studies.

    PubMed

    Srivastava, Garima; Singh, Kritika; Talat, Mahe; Srivastava, Onkar Nath; Kayastha, Arvind M

    2014-01-01

    β-Amylase finds application in food and pharmaceutical industries. Functionalized graphene sheets were customised as a matrix for covalent immobilization of Fenugreek β-amylase using glutaraldehyde as a cross-linker. The factors affecting the process were optimized using Response Surface Methodology based Box-Behnken design of experiment which resulted in 84% immobilization efficiency. Scanning and Transmission Electron Microscopy (SEM, TEM) and Fourier Tansform Infrared (FTIR) spectroscopy were employed for the purpose of characterization of attachment of enzyme on the graphene. The enzyme kinetic studies were carried out for obtaining best catalytic performance and enhanced reusability. Optimum temperature remained unchanged, whereas optimum pH showed shift towards acidic range for immobilized enzyme. Increase in thermal stability of immobilized enzyme and non-toxic nature of functionalized graphene can be exploited for production of maltose in food and pharmaceutical industries.

  9. Spectroscopy study of Zn, Cd, Pb and Cr ions immobilization on C-S-H phase.

    PubMed

    Żak, Renata; Deja, Jan

    2015-01-05

    Calcium silicate hydrates (C-S-H) have a large number of structural sites available for cations and anions to bind. The C-S-H phases are materials which have ability to toxic ions immobilization. Immobilization mechanisms for C-S-H include sorption, phase mixing, substitution and precipitation of insoluble compounds. This study presents the C-S-H (prepared with C/S ratios 1.0) phase as absorbent for immobilization of Zn, Cd, Pb and Cr ions. The C-S-H spectra before and after incorporation of heavy metals ions into the C-S-H structure were obtained. The effect of added heavy metals ions on the hydration phenomena was studied by means of X-ray diffractions analysis. FTIR spectra was measured. The microstructure and phase composition of C-S-H indicate that they can play an essential role in the immobilization of heavy metals. The properties of C-S-H in the presence of Zn, Cd, Pb and Cr cations were studied. The leaching ML test was used to evaluate the level of immobilization of heavy metals in C-S-H. The leached solutions are diluted and analyzed using atomic absorption spectrometry (AAS) and the activated solid particles are separated, washed, desiccated and analyzed by Fourier transform infrared (FTIR) spectroscopy. It was found that the degree of Cd, Zn, Pb and Cr cations immobilization was very high (exceeding 99.96%).

  10. Adaptive Motor Imagery: A Multimodal Study of Immobilization-Induced Brain Plasticity.

    PubMed

    Burianová, Hana; Sowman, Paul F; Marstaller, Lars; Rich, Anina N; Williams, Mark A; Savage, Greg; Al-Janabi, Shahd; de Lissa, Peter; Johnson, Blake W

    2016-03-01

    The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  11. Immobilized low-level waste disposal options configuration study

    SciTech Connect

    Mitchell, D.E.

    1995-02-01

    This report compiles information that supports the eventual conceptual and definitive design of a disposal facility for immobilized low-level waste. The report includes the results of a joint Westinghouse/Fluor Daniel Inc. evaluation of trade-offs for glass manufacturing and product (waste form) disposal. Though recommendations for the preferred manufacturing and disposal option for low-level waste are outside the scope of this document, relative ranking as applied to facility complexity, safety, remote operation concepts and ease of retrieval are addressed.

  12. Mental practice maintains range of motion despite forearm immobilization: a pilot study in healthy persons.

    PubMed

    Frenkel, Marie O; Herzig, Daniela S; Gebhard, Florian; Mayer, Jan; Becker, Clemens; Einsiedel, Thomas

    2014-03-01

    To determine whether mental practice of wrist movements during forearm immobilization maintains range of motion. Randomized controlled trial. Eighteen healthy young men aged between 20 and 30 years were assigned to either a control or a mental practice group. Both groups were immobilized with a circular forearm cast for 3 weeks to simulate a distal radial fracture. The mental practice group received 1 × 60-min, followed by 3 × 30-min, sessions of supervised mental practice. Consecutively, they were asked to perform 15 min/day of self-guided imagery sessions, during which they mentally exercised motion sequences of the immobilized joint. The training program followed the Mental Gait Training procedure. The control group did no training. Wrist movement was measured with a goniometer before and after immobilization. Mental practice preserved dorsal extension and ulnar abduction. The sedentary control group showed due to this variables a significant decrease after cast removal. There was no significant change in palmar flexion and radial abduction in either group. Despite the study limitations, these results suggest that mental practice may be useful in preventing loss of hand function associated with mid-term immobilization. Because of the expected clinical benefits, the low cost and simple application of the intervention, the effects of mental practice in orthopedic rehabilitation of the upper extremity warrant further study.

  13. Studies on improving the immobilized bead reusability and alkaline protease production by isolated immobilized Bacillus circulans (MTCC 6811) using overall evaluation criteria.

    PubMed

    Subba Rao, Ch; Madhavendra, S S; Sreenivas Rao, R; Hobbs, Phil J; Prakasham, R S

    2008-07-01

    This study uses an overall evaluation criterion for improving the immobilized bead reusability and extracellular enzyme production by immobilized cells by assigning relative weightage to bead reusability, enzyme production, and cell leakage. Initially, alkaline protease production by alginate-immobilized Bacillus circulans (MTCC 6811) was analyzed using L18 orthogonal array (OA). The resultant optimized parameters were further fine-tuned with L9 OA experimentation. At L18-OA analysis, inoculum level and CaCl(2) had least influence at individual level. At the interactive level, incubation time revealed maximum and minimum interaction with sodium alginate and glucose concentration, respectively. L9 experimentation indicated that glucose concentration contributed the major influence on protease production followed by matrix material and incubation time at the individual level, and at the interactive level, matrix concentration played a vital role by interacting with incubation time, inoculum, and CaCl(2) concentration. All selected input parameters showed significance either at individual level or interactive in both OAs. Scanning electron microscopy analysis showed bacterial morphology variation with variation of matrix concentration. Overall, glucose concentration depicted a major influence at the individual level for the enzyme production. Significant improvement, approximately 147%, in enzyme yield was observed. Economic enzyme production by immobilized B. circulans is regulated by interactive influence of fermentation parameters, which influence the immobilized bead stability, reusability, and enzyme yield.

  14. Kinetic study of Candida antarctica lipase B immobilization using poly(methyl methacrylate) nanoparticles obtained by miniemulsion polymerization as support.

    PubMed

    Valério, Alexsandra; Nicoletti, Gabrieli; Cipolatti, Eliane P; Ninow, Jorge L; Araújo, Pedro H H; Sayer, Cláudia; de Oliveira, Débora

    2015-03-01

    With the objective to obtain immobilized Candida antarctica lipase B (CalB) with good activity and improved utilization rate, this study evaluated the influence of enzyme and crodamol concentrations and initiator type on the CalB enzyme immobilization in nanoparticles consisting of poly(methyl methacrylate) (PMMA) obtained by miniemulsion polymerization. The kinetic study of immobilized CalB enzyme in PMMA nanoparticles was evaluated in terms of monomer conversion, particle size, zeta potential, and relative activity. The optimum immobilization condition for CalB was compared with free enzyme in the p-NPL hydrolysis activity measurement. Results showed a higher CalB enzyme stability after 20 hydrolysis cycles compared with free CalB enzyme; in particular, the relative immobilized enzyme activity was maintained up to 40%. In conclusion, PMMA nanoparticles proved to be a good support for the CalB enzyme immobilization and may be used as a feasible alternative catalyst in industrial processes.

  15. Comparison between Free and Immobilized Ion Effects on Hydrophobic Interactions: A Molecular Dynamics Study.

    PubMed

    Huang, Kai; Gast, Sebastian; Ma, C Derek; Abbott, Nicholas L; Szlufarska, Izabela

    2015-10-15

    Fundamental studies of the effect of specific ions on hydrophobic interactions are driven by the need to understand phenomena such as hydrophobically driven self-assembly or protein folding. Using β-peptide-inspired nanorods, we investigate the effects of both free ions (dissolved salts) and proximally immobilized ions on hydrophobic interactions. We find that the free ion effect is correlated with the water density fluctuation near a nonpolar molecular surface, showing that such fluctuation can be an indicator of hydrophobic interactions in the case of solution additives. In the case of immobilized ion, our results demonstrate that hydrophobic interactions can be switched on and off by choosing different spatial arrangements of proximal ions on a nanorod. For globally amphiphilic nanorods, we find that the magnitude of the interaction can be further tuned using proximal ions with varying ionic sizes. In general, univalent proximal anions are found to weaken hydrophobic interactions. This is in contrast to the effect of free ions, which according to our simulations strengthen hydrophobic interactions. In addition, immobilized anions of increasing ionic size do not follow the same ordering (Hofmeister-like ranking) as free ions when it comes to their impact on hydrophobic interactions. The immobilized ion effect is not simply correlated with the water density fluctuation near the nonpolar side of the amphiphilic nanorod. We propose a molecular picture that explains the contrasting effects of immobilized versus free ions.

  16. Laccase production by free and immobilized mycelia of Peniophora cinerea and Trametes versicolor: a comparative study.

    PubMed

    Silvério, Sara C; Moreira, Sérgio; Milagres, Adriane M F; Macedo, Eugénia A; Teixeira, José A; Mussatto, Solange I

    2013-03-01

    The production of laccase by immobilized mycelia of Peniophora cinerea and Trametes versicolor was studied. In an initial stage, experimental assays were performed in Erlenmeyer flasks using free and immobilized mycelium, and the performance of the fungal strains to produce the enzyme was compared. Both fungi adhered into the support material (a synthetic fiber), growing not only on the surface but also in the interspaces of the fibers. Immobilization of P. cinerea provided a 35-fold increase in laccase production when compared to the production obtained by using free mycelium. On the other hand, immobilization of T. versicolor caused a decrease in laccase activity. A comparison between the strains revealed that immobilized P. cinerea (3,500 U/L) surpassed the enzyme production by free T. versicolor (800 U/L). When the conditions that gave the best laccase production to each fungus were employed in a stirred tank bioreactor, very low laccase production was observed for both the cases, suggesting that shear stress and mycelia damage caused by the agitation impellers negatively affected the enzyme production.

  17. [Methods of microorganism immobilization for dynamic atomic-force studies (review)].

    PubMed

    Kuiukina, M S; Korshunova, I O; Rubtsova, E V; Ivshina, I B

    2014-01-01

    Atomic-force microscopy (AFM) is an efficient method for studying the surface ultrastructure and nanomechanical properties of biological objects (including microorganisms). A correctly selected method of microorganism immobilization (that provides a strong attachment of cells on the surface of a biologically inert substrate and the preservation of their native properties) is an important condition of AFM scanning in a liquid medium. Comparative characteristics of methods of microorganism immobilization (that are applied in dynamic AFM studies) are given in the review. Technologies of mechanical retention and chemical binding of cells to a substrate, as well as protein and immunospecific adsorption, are considered.

  18. Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

    NASA Astrophysics Data System (ADS)

    Docters, E. H.; Smolko, E. E.; Suarez, C. E.

    The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

  19. Comparative study of 6-APA production by free and agar immobilized bacteria in nutrient broth culture.

    PubMed

    Dolui, A K; Das, S

    2011-04-01

    In the present study different bacterial samples were isolated from soil of different places of Dibrugarh and screened for biotransformation ability to produce 6-Aminopenicillanic acid. Among ten isolated bacterial samples, three gram positive bacterial samples designated as AKDD-2, AKDD-4 and AKDD-6 showed the production of 6-APA from penicillin G. Assessment of production of 6-APA after incubation in penicillin G (2 mg/ml) by three different samples separately in free and agar immobilization state was done by HPLC analysis. Reusability of immobilized cells was found successful up to 14 days.

  20. Flow-through immobilized enzyme reactors based on monoliths: II. Kinetics study and application.

    PubMed

    Vlakh, Evgenia G; Tennikova, Tatiana B

    2013-03-01

    In the last decade, the application of monolithic materials has rapidly expanded to the realization of flow-through bioconversion processes. Up to these days, different classes of enzymes such as hydrolases, lyases, and oxidoreductases have been immobilized on organic, inorganic, or hybrid monolithic materials to prepare the effective flow-through enzymes reactors for application in proteomics, biotechnology, pharmaceutics, organic synthesis, and biosensoring. Current review describes the results of kinetic study and specialties of flow-through immobilized enzyme reactors based on the existing monolithic materials.

  1. Study of bone mineral metabolism. [during body immobilization, bed rest, and space flight

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.

    1975-01-01

    The use of Sr-85 as an indicator of the skeletal location and relative amount of bone demineralization which occurs during immobilization of the body or body parts, bed-rest or space flight was studied. The bone mineral replacement which occurs after immobilization was measured rather than the bone loss which occurs during immobilization. In a study with two adult beagle dogs, the Sr-85 uptake in a leg which had been immobilized for two months was 400 percent higher than the uptake in the legs in regular use. This increased uptake probably resulted from only a few percent loss in bone mineral and indicates that losses less than one percent can be easily detected and located. The sensitivity, simplicity, and low radiation dose associated with the use of this method indicates that it should receive consideration for use on humans in bed-rest and space flight studies. Methods for measuring changes in total body nitrogen and in assisting the Johnson Space Center in calibrating a whole body counter for total body potassium measurements were also investigated.

  2. Mechanistic study for immobilization of cysteine-labeled oligopeptides on UV-activated surfaces.

    PubMed

    Ong, Lian Hao; Ding, Xiaokang; Yang, Kun-Lin

    2014-10-01

    In this study, we report immobilization of cysteine-labeled oligopeptides on UV activated surfaces decorated with N,N-dimethyl-n-octadecyl-3-aminopropyltrimethoxysilyl chloride (DMOAP). Our result shows that cysteine group, regardless of its position in the oligopeptide, is essential for successful immobilization of oligopeptide on the UV-activated surface. A possible reaction mechanism is nucleophilic addition of thiolates to surface aldehyde groups generated during UV activation. By using this technique, we are able to incorporate anchoring points into oligopeptides through cysteine residues. Furthermore, immobilized oligopeptides on the UV-activated surface is very stable even under harsh washing conditions. Finally, we show that an HPQ-containing oligopeptide can be immobilized on the UV-activated surface, but the final surface density and its ability to bind streptavidin are affected by the position of cysteine and HPQ. An oligopeptide with a cysteine at the N-terminus and a HPQ motif at the C-terminus gives the highest binding signal in the streptavidin-binding assay. This result is potentially useful for the development of functional oligopeptide microarrays for detecting target protein molecules.

  3. [Study on immobilized cells for producing alpha-amylase by using polyving alcohol as the carrier(II): The effect of fermentating conditions on the ability producing alpha-amylase of the cells immobilized with polyving alcohol as the corrier and continuous fermentation of the immobilized cells in CSTR].

    PubMed

    Liu, Z; Wang, J; Li, Z

    1998-03-01

    The effects of fermentating conditions on the ability of immobilized cells with PVA as carrier for producing alpha-amylase were studied. The continuous fermentation with the immobilized cells were tested in continuous flow stirred tank reactor (CSTR). The results showed that the adaptability of the immobilized Bacillus substilis to pH increased after immobilization. In CSTR, the immobilized cells can be fermentated continuously for 360 hrs and the activity of alpha-amylase can be kept on the level of about 170 u/ml.

  4. A preliminary study of continuous milk coagulation using Cynara cardunculus flower extract and calf rennet immobilized on magnetic particles.

    PubMed

    Liburdi, Katia; Emiliani Spinelli, Sara; Benucci, Ilaria; Lombardelli, Claudio; Esti, Marco

    2018-01-15

    The aim of this study was to develop a bioreactor design for continuous milk coagulation using a biocatalyst composed of immobilized animal and vegetable rennet on aminated magnetic particles, which has been proven to be an appropriate carrier for enzyme immobilization. Calf and vegetable (Cynara cardunculus) rennets were covalently immobilized on CLEA® magnetic supports and the immobilization procedure was optimized in batch mode, by evaluating protein loading, caseinolytic activity and the coagulation properties of skim milk powder and cow's milk. Subsequently the optimal temperature of immobilized coagulant was defined and a technically-friendly enzyme bioreactor was developed in order to carry out a continuous milk coagulation process with the aim of producing soft cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Kinetic modeling and docking study of immobilized lipase catalyzed synthesis of furfuryl acetate.

    PubMed

    Mathpati, Ashwini C; Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2016-03-01

    The present work deals with the kinetic modeling and docking study for the furfuryl acetate synthesis using immobilized Burkholderia cepacia (BCL) lipase. Initially various lipases were immobilized on hydroxypropyl methyl cellulose (HPMC) and poly vinyl alcohol (PVA) base hybrid polymer matrix. After screening of various immobilized biocatalysts, HPMC:PVA:BCL was found to be a robust biocatalyst. Various reaction conditions were optimized using response surface methodology (RSM) based on a four-factor-three-level Box-Behnken design. The optimal conditions were obtained at molar ratio of 1:2 of furfuryl alcohol to acyl donor, temperature 50°C with catalyst loading of 30mg in 3mL of non-aqueous media toluene. Under these conditions 99.98% yield was obtained in 3h. The Arrhenius plot showed that the activation energy for furfuryl acetate synthesis was 10.68kcal/mol. The kinetics of reaction was studied close to optimized conditions which obey order bi-bi model. Molecular docking study was carried out to understand the active site of BCL which is responsible for the reaction. It was observed that the reaction proceeds via acylation of the active serine of BCL and demonstrating strong hydrogen bond between the substrate and histidine site. The catalyst recyclability study was carried up to five cycles.

  6. Electrochemical study of gelatin as a matrix for the immobilization of horse heart cytochrome c.

    PubMed

    De Wael, Karolien; De Belder, Stijn; Van Vlierberghe, Sandra; Van Steenberge, Geert; Dubruel, Peter; Adriaens, Annemie

    2010-10-15

    The aim of this paper is to emphasize the strength of gelatin as a stable matrix for redox enzymes. Cyclic voltammetry has been applied for a detailed electrochemical study of horse heart cytochrome c (HHC) entrapped in a gelatin matrix immobilized on a gold electrode. The influence of the HHC concentration, the mass percentage of the gelatin and the nature of the gelatin on the electrochemical behaviour of HHC have been described in detail. In addition, attenuated total reflection infrared (ATR-IR) spectroscopy was used to prove the immobilization on a qualitative and conformational level. The thickness of the gelatin film was determined using a non-contact optical profiler. These results open up new perspectives in the development of stable, biocompatible matrices for redox enzymes. The latter has its relevance in the field of biosensor development.

  7. Subsurface Bio-Immobilization of Plutonium: Experiment and Model Validation Study

    SciTech Connect

    Reed, Donald; Rittmann, Bruce

    2006-06-01

    The goal of this project is to conduct a concurrent experimental and modeling study centered on the interactions of Shewanella algae BrY with plutonium and uranium species and phases. The most important objective of this research is to investigate the long-term stability of bioprecipitated immobilized actinide phases under changing redox conditions in biologically active systems. The long-term stability of bio-immobilized actinides (e.g. by bio-reduction) is a key criteria that defines the utility and effectiveness of a remediation/containment strategy for subsurface actinide contaminants. Plutonium, which is the focus of this project, is the key contaminant of concern at several DOE sites.

  8. Covalent Immobilization of Biotin on Magnetic Nanoparticles: Synthesis, Characterization, and Cytotoxicity Studies.

    PubMed

    Islam, Md Rafiqul; Bach, Long Giang; Vo, Thanh-Sang; Lim, Kwon Taek

    2015-01-01

    A simple protocol for covalent immobilization of biotin onto the surface of Fe3O4 magnetic nanoparticles (MNPs) for improving the biocompatibility of original MNPs has been realized. MNPs were first prepared by co-precipitation method which was subsequently anchored with functionalized biotin. The as-synthesized MNPs were observed to be monocrystalline as evidenced from XRD and TEM images. The covalent grafting of biotin to MNPs was confirmed by FT-IR. The XPS analysis suggested the successful preparation of Biotin-f-MNPs. The as-synthesized Biotin-f-MNPs were found to be superparamagnetic character as recorded by SQUID. Cell viability studies revealed that the biocompatibility of MNPs was improved upon Biotin immobilization.

  9. Hydrated lime for metals immobilization and explosives transformation: Treatability study.

    PubMed

    Martin, W Andy; Larson, S L; Nestler, C C; Fabian, G; O'Connor, G; Felt, D R

    2012-05-15

    Fragmentation grenades contain Composition B (RDX and TNT) within a steel shell casing. There is the potential for off-site migration of high explosives and metals from hand grenade training ranges by transport in surface water and subsurface transport in leachate. This treatability study used bench-scale columns and mesocosm-scale laboratory lysimeters to investigate the potential of hydrated lime as a soil amendment for in situ remediation of explosives and metals stabilization in hand grenade range soils. Compared to the unamended soil there was a 26-92% reduction of RDX in the leachate and runoff water from the lime treated soils and a 66-83% reduction of zinc in the leachate and runoff water samples; where the hand grenade range metals of concern were zinc, iron, and manganese. The amended soil was maintained at the target pH of greater than 10.5 for optimum explosives decomposition. The treatability study indicated a high potential of success for scale-up to an in situ field study.

  10. Advantages of using non-isothermal bioreactors in agricultural waste water treatment by means of immobilized urease. Study on the influence of spacer length and immobilization method.

    PubMed

    El Sherif, Hazem; Di Martino, Silvana; Travascio, Paola; De Maio, Anna; Portaccio, Marianna; Durante, Daniela; Rossi, Sergio; Canciglia, Paolo; Mita, Damiano G

    2002-05-08

    The behavior of three different catalytic membranes, obtained by immobilizing urease on nylon sheets chemically grafted with methyl methacrylate, was studied in a bioreactor operating under isothermal and non-isothermal conditions. Membrane activation was carried out by condensation or acyl azide reaction, and spacers of different lengths, such as hexamethylendiamine or hydrazine, were used. Under isothermal conditions, the activities of the catalytic membranes and soluble urease were characterized as a function of pH, temperature, and urea concentration. Both enzyme forms showed the same optimum pH, whereas the optimum temperature was lower for the immobilized enzymes. The spacer length appeared to determine broader pH- and temperature-activity profiles for the urease derivatives. The apparent K(m) values of the insoluble urease were dependent on membrane type and were higher than those of the soluble counterpart, thus indicating an affinity loss for urea. Under non-isothermal conditions, all membranes exhibited an increase of percentage activity proportional to the applied temperature difference and decreasing with the increase of urea concentrations. A decrease of the apparent K(m) was also observed. These results suggest that substrate diffusion limitations due to the immobilization process can be overcome in the presence of temperature gradients. In addition, the remarkable reduction of the production times supports the use of non-isothermal bioreactors for the treatment of urea-polluted waste waters.

  11. Glyphosate degradation by immobilized bacteria: laboratory studies showing feasibility for glyphosate removal from waste water.

    PubMed

    Heitkamp, M A; Adams, W J; Hallas, L E

    1992-09-01

    To evaluate immobilized bacteria technology for the removal of low levels of glyphosate (N-phosphonomethylglycine) from aqueous industrial effluents, microorganisms with glyphosate-degrading activity obtained from a fill and draw enrichment reactor inoculated with activated sludge were first exposed to glyphosate production wastes containing 500-2000 mg glyphosate/L. The microorganisms were then immobilized by adsorption onto a diatomaceous earth biocarrier contained in upflow Plexiglas columns. The columns were aerated, maintained at pH 7.0-8.0, incubated at 25 degrees C, supplemented with NH4NO3 (50 mg/L), and exposed to glyphosate process wastes pumped upflow through the biocarrier. Glyphosate degradation to aminomethylphosphonic acid was initially > 96% for 21 days of operation at flows yielding hydraulic residence times (HRTs) as short as 42 min. Higher flow rate studies showed > 98% removal of 50 mg glyphosate/L from the waste stream could be achieved at a HRT of 23 min. Glyphosate removal of > 99% at a 37-min HRT was achieved under similar conditions with a column inoculated with a pure culture of Pseudomonas sp. strain LBr, a bacterium known to have high glyphosate-degrading activity. After acid shocking (pH 2.8 for 18 h) of a column of immobilized bacteria, glyphosate-degrading activity was regained within 4 days without reinoculation. Although microbial growth and glyphosate degradation were not maintained under low organic nutrient conditions in the laboratory, the low levels of degradable carbon (45-94 mg/L) in the industrial effluent were sufficient to support prolonged glyphosate-degrading activity. The results demonstrated that immobilized bacteria technology is effective in removing low levels of glyphosate in high-volume liquid waste streams.

  12. Preparation of enzyme nanoparticles and studying the catalytic activity of the immobilized nanoparticles on polyethylene films.

    PubMed

    Meridor, David; Gedanken, Aharon

    2013-01-01

    Using high-intensity ultrasound, in situ generated α-amylase nanoparticles (NPs) were immobilized on polyethylene (PE) films. The α-amylase NP-coated PE films have been characterized by E-SEM, FTIR, DLS, XPS and RBS. The PE was reacted with HNO(3) and NPs of the α-amylase were also deposited on the activated PE. The PE impregnated with α-amylase (4 μg per 1mg PE) was used for hydrolyzing soluble potato starch to maltose. The immobilization improved the catalytic activity of α-amylase at all the reaction conditions studied. The kinetic parameters, K(m) (5 and 4 g L(-1) for the regular and activated PE, respectively) and V(max) (5 × 10(-7) mol ml(-1) min(-1), almost the same numbers were obtained for the regular and activated PEs) for the immobilized amylase were found to slightly favor the respective values obtained for the free enzyme (K(m) = 6.6 g L(-1), V(max) = 3.7 × 10(-7) mol ml(-1) min(-1)). The enzyme remained bound to PE even after soaking the PE in a starch solution for 72 h and was still found to be weakly active. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. High pressure studies on hesperitin production with hesperidinase free and immobilized in calcium alginate beads

    NASA Astrophysics Data System (ADS)

    Furtado, Andreia; Rosário, Pedro M.; Calado, António R. T.; Alfaia, António J. I.; Ribeiro, Maria H. L.

    2012-03-01

    The use of high pressure for the enzymatic synthesis of pharmacologically interesting molecules is a very important tool. Hesperidin and hesperitin exhibit anti-inflammatory, antimicrobial, antioxidant, and anticarcinogenic properties and prevent bone loss. However, hesperidin has a low bioavailability compared with hesperitin, due to the rutinoside moiety attached to the flavonoid. The aim of this work was the enzymatic production of hesperitin from hesperidin (soluble and insoluble) with hesperidinase free and immobilized in Ca-alginate beads, under high pressure conditions. The work was focused on the optimization of enzyme activity, studying the effects: pressure (50-150 MPa), temperature (35-75 °C), concentration of substrate (100-800 mg/L), and immobilization of hesperidinase. An 18-fold increase in hesperidinase residual activity was observed under high pressure conditions of 100 MPa compared to 0.1 MPa. A higher specificity of the hydrolytic reaction under high pressure (100 MPa) with a two-and three-fold increase in the ratio K cat/K M (specificity constant) at 55 °C and 75 °C was observed. A two-fold increase in the maximum activity at 100 MPa was observed with immobilized hesperinase compared to 0.1 MPa. In the second reutilization, almost a four-fold increase was obtained under high pressure conditions in comparison to atmospheric pressure.

  14. Double-Barrier mechanism for chromium immobilization: A quantitative study of crystallization and leachability.

    PubMed

    Liao, Changzhong; Tang, Yuanyuan; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai

    2016-07-05

    Glass-ceramics are well known for the excellent combination properties provided by their components, a glassy matrix and crystalline phases, and have promising applications in the immobilization and detoxification of solid waste containing toxic metals. Glass-ceramic products were successfully synthesized in CaO-MgO-SiO2-Al2O3 -Cr2O3 system. Two key measures--partitioning ratio of Cr in the spinel and Cr leaching ratio--were used to investigate the mechanism of Cr immobilization in the glass-ceramic products. The results of powder X-ray diffraction revealed that both spinel and diopside were major crystalline phases in the products. The value of x in the MgCr(x)Al(2-x)O4 spinel was highly related to the amount of Cr2O3 added to the glass-ceramic system. As Cr2O3 content increased, the proportion of spinel phase increased, while that of glass phase decreased. The partitioning ratio of Cr in spinel phase was about 70% for 2 wt.% Cr2O3, and increased to 90% when loaded with 10 wt.% of Cr2O3. According to the results of the prolonged toxicity characteristic leaching procedure, the Cr leaching ratio decreased with the increase of Cr partitioning ratio into the spinel phase. The findings of this study clearly indicate that glass-ceramic formed by spinel structure and residual glass successfully immobilized Cr.

  15. [Study of immobilization and properties of urease for creation of a biosensor based on semiconductor structures].

    PubMed

    Bubriak, O A; Khustochka, L N; Soldatkin, A P; Starodub, N F

    1992-01-01

    Many-sided investigations of urease immobilization methods were carried out to create the biosensor devices on the base of semiconductor structures. Special attention was concentrated on the biomembrane formation by means of urease and bovine serum albumin (BSA) cross-linking by gaseous glutaraldehyde. Optimal conditions for the formation process were selected which preserve about 20% of total urease activity after the cross-linking. The properties of enzyme immobilized by the above-mentioned method have been comprehensively studied. They included the urease activity dependence on pH, ionic strength, incubation buffer capacity as well as the enzyme stability during its functioning, storing and thermoinactivation. As was shown, for immobilized ureas Km value for urea at pH 7.0 and 20 degrees C is 1.65 time less than for free enzyme. In the presence of EDTA (1 mM) the enzyme activity in the biomembrane is practically unchanged under a month storing. Biomembrane possesses good adhesion to silicon surface and its swelling level under different conditions does not exceed 35%. The conclusion is made about the prospects of the used method of biomembrane formation for biosensor technology based on semiconductor structures.

  16. [Study on influence between activated carbon property and immobilized biological activated carbon purification effect].

    PubMed

    Wang, Guang-zhi; Li, Wei-guang; He, Wen-jie; Han, Hong-da; Ding, Chi; Ma, Xiao-na; Qu, Yan-ming

    2006-10-01

    By means of immobilizing five kinds of activated carbon, we studied the influence between the chief activated carbon property items and immobilized bioactivated carbon (IBAC) purification effect with the correlation analysis. The result shows that the activated carbon property items which the correlation coefficient is up 0.7 include molasses, abrasion number, hardness, tannin, uniform coefficient, mean particle diameter and effective particle diameter; the activated carbon property items which the correlation coefficient is up 0.5 include pH, iodine, butane and tetrachloride. In succession, the partial correlation analysis shows that activated carbon property items mostly influencing on IBAC purification effect include molasses, hardness, abrasion number, uniform coefficient, mean particle diameter and effective particle diameter. The causation of these property items bringing influence on IBAC purification is that the activated carbon holes distribution (representative activated carbon property item is molasses) provides inhabitable location and adjust food for the dominance bacteria; the mechanical resist-crash property of activated carbon (representative activated carbon property items: abrasion number and hardness) have influence on the stability of biofilm; and the particle diameter size and distribution of activated carbon (representative activated carbon property items: uniform coefficient, mean particle diameter and effective particle diameter) can directly affect the force of water in IBAC filter bed, which brings influence on the dominance bacteria immobilizing on activated carbon.

  17. Study of ionic liquid immobilization on polyvinyl ferrocene substrates for gas sensor arrays.

    PubMed

    Hou, Kuang-Yu; Rehman, Abdul; Zeng, Xiangqun

    2011-04-19

    In this report, the effects of conductive polymer oxidation states and structures on the design and development of ionic liquid (IL)/conductive polymer (CP) composite films for gas sensing are systematically characterized. Four different polyvinyl ferrocene (PVF) films synthesized by varying the conditioning potential (0.7 vs 0.0 V) and the electrolyte are tested for their gas-sensing properties (e.g., sensitivity, selectivity, response time, linearity, and dynamic range against various gas analytes such as dichloromethane, ethanol, natural gas, methane, formaldehyde (37%), and benzene) utilizing the quartz crystal microbalance (QCM) and ATR-FT-IR. The best available film is further studied as a substrate for the immobilization of various ILs that enhanced both the sensitivity and selectivity. Finally, two arrays, each comprising four sensors with the following scheme are developed and characterized for their ability to classify the four target analytes by using linear discriminant analysis: (1) the highest sensitivity PVF film immobilized with four different ILs and (2) the highest sensitivity IL immobilized in four different PVF films. Array 2 is proven to be much better than array 1 in discriminating the analytes, which is very significant in establishing the fact that a diverse set of PVF redox states allow the rational development of a PVF/IL composite-based sensor array in order to analyze complex mixtures utilizing structural differences and the extent of intermolecular interactions.

  18. Determinants of bone mineral density in immobilization: a study on hemiplegic patients.

    PubMed

    del Puente, A; Pappone, N; Mandes, M G; Mantova, D; Scarpa, R; Oriente, P

    1996-01-01

    Osteoporosis that develops during immobilization is a severe condition that confers increased risk of fractures with their burden of mortality and disability. The aim of this study was to investigate the determinants of immobilization osteoporosis. As a model of this condition we studied hemiplegic subjects, measuring bone mineral density in the paralyzed lower limb as compared with the non-paralyzed one. In spite of the limits related to the loss of nervous stimulation, this model offers the advantage of a proper control for the complex genetic and environmental cofactors involved. We examined 48 hemiplegic subjects (31 men, 17 women in menopause) admitted consecutively over a 9-month period. Mean length immobilization was 10.9 months for men (range 1-48 months) and 7.8 months for women (range 1-40 months). The average time since menopause was 14.9 years (range 1.7-23.9 years). For each subject the following were performed: questionnaire, medical examination, anthropometric measurements, evaluation of the scores for spasticity and for lower limb motor capacity in order to account for the different degrees of disability among patients. Bone mineral density was measured using dual-energy X-ray absorptiometry (DXA) at both femoral necks. For each patient we defined a percentage difference in bone loss between the paralyzed and non-paralyzed limb. Regression coefficient were calculated by multiple logistic regression. There was significant bone loss in the paralyzed limb in both sexes, accounting for up to 6.3% in women. Multiple regression analysis showed that the degree of bone loss depends significantly and directly on the length of immobilization, even when controlling for age and sex in the regression model (R = 0.193, p = 0.034). However, when time since menopause was included in the regression model, with length of immobility as a covariate, it was the only significant determinant of bone loss (R = 0.312, p = 0.039). No additional factors were observed among

  19. Immobilized lysozyme for the continuous lysis of lactic bacteria in wine: Bench-scale fluidized-bed reactor study.

    PubMed

    Cappannella, Elena; Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Bavaro, Teodora; Esti, Marco

    2016-11-01

    Lysozyme from hen egg white (HEWL) was covalently immobilized on spherical supports based on microbial chitosan in order to develop a system for the continuous, efficient and food-grade enzymatic lysis of lactic bacteria (Oenococcus oeni) in white and red wine. The objective is to limit the sulfur dioxide dosage required to control malolactic fermentation, via a cell concentration typical during this process. The immobilization procedure was optimized in batch mode, evaluating the enzyme loading, the specific activity, and the kinetic parameters in model wine. Subsequently, a bench-scale fluidized-bed reactor was developed, applying the optimized process conditions. HEWL appeared more effective in the immobilized form than in the free one, when the reactor was applied in real white and red wine. This preliminary study suggests that covalent immobilization renders the enzyme less sensitive to the inhibitory effect of wine flavans. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. [Study on CTP production from CMP by beer yeast cell immobilized in PVA].

    PubMed

    Yang, Hong-Yi; Qian, Shi-Jun; Li, Gao-Wo

    2007-03-01

    With PVA as the carrier, the frozen beer yeast cells were immobilized for production of CTP from CMP. we explored the optimal condition of the immobilization from the aspects of the type, concentration of the PVA, and the immobilizing methods of cells In all 8 continuous batch of fermentation under the reactional condition of the immobilized cells, the conversion rate of CTP were maintained about 85% - 95%. Moreever, the storage stability of immobilized cells were investigated, and the products was also isolated and identifided by HPLC.

  1. In vitro metabolic study of Rhizoma coptidis extract using liver microsomes immobilized on magnetic nanoparticles.

    PubMed

    Xue, Ying; Xiong, Jing; Shi, Hai-Li; Liu, Yi-Ming; Qing, Lin-Sen; Liao, Xun

    2013-11-01

    Although metabolic study of individual active compounds isolated from herbal plants has been intensive, it cannot truly reflect the fate of herbs because the herbal extracts in use have many constituents. To address this problem, whole extracts of herbs should be investigated. Microsomes have been heavily used in the in vitro metabolic study of drugs, and various materials have been used to immobilize microsomes to develop highly effective and reusable bioreactors in this field. In this work, rat liver microsomes were immobilized on magnetic nanoparticles (LMMNPs) to develop a highly active and recoverable nanoparticle bioreactor. Using this bioreactor, we investigated the in vitro metabolism of Rhizoma coptidis extract. Incubation of berberine, a major active ingredient of R. coptidis, with LMMNPs for 20 min produced two metabolites, i.e., demethyleneberberine and thalifendine, at high levels. From a comparison of the time courses of thalifendine formation obtained by ultraperformance liquid chromatography-mass spectrometry analysis, it was found that LMMNPs had a higher biological activity than free liver microsomes in metabolizing berberine. Further, the activity of LMMNPs remained almost unchanged after six consecutive uses in the incubation tests. Metabolism of R. coptidis extracts by LMMNPs was studied. The same two metabolites of berberine, i.e., demethyleneberberine and thalifendine, were detected. After a thorough study seeking support for this observation, it was found that demethyleneberberine was the common metabolite of five protoberberine-type alkaloids present in R. coptidis extract, including palmatine, jatrorrhizine, columbanine, epiberberine, and berberine.

  2. BIOINTERACTION ANALYSIS BY HIGH-PERFORMANCE AFFINITY CHROMATOGRAPHY: KINETIC STUDIES OF IMMOBILIZED ANTIBODIES

    PubMed Central

    Nelson, Mary Anne; Moser, Annette; Hage, David S.

    2009-01-01

    A system based on high-performance affinity chromatography was developed for characterizing the binding, elution and regeneration kinetics of immobilized antibodies and immunoaffinity supports. This information was provided by using a combination of frontal analysis, split-peak analysis and peak decay analysis to determine the rate constants for antibody-antigen interactions under typical sample application and elution conditions. This technique was tested using immunoaffinity supports that contained monoclonal antibodies for 2,4-dichlorophenoxyacetic acid (2,4-D). Association equilibrium constants measured by frontal analysis for 2,4-D and related compounds with the immobilized antibodies were 1.7–12 × 106 M−1 at pH 7.0 and 25°C. Split-peak analysis gave association rate constants of 1.4–12 × 105 M−1s−1 and calculated dissociation rate constants of 0.01–0.4 s−1 under the application conditions. Elution at pH 2.5 for the analytes from the antibodies was examined by peak decay analysis and gave dissociation rate constants of 0.056–0.17 s−1. A comparison of frontal analysis results after various periods of column regeneration allowed the rate of antibody regeneration to be examined, with the results giving a first-order regeneration rate constant of 2.4 × 10−4 s−1. This combined approach and the information it provides should be useful in the design and optimization of immunoaffinity chromatography and other analytical methods that employ immobilized antibodies. The methods described are not limited to the particular analytes and antibodies employed in this study but should be useful in characterizing other targets, ligands and supports. PMID:19394281

  3. "Click" immobilization on alkylated silicon substrates: model for the study of surface bound antimicrobial peptides.

    PubMed

    Li, Yan; Santos, Catherine M; Kumar, Amit; Zhao, Meirong; Lopez, Analette I; Qin, Guoting; McDermott, Alison M; Cai, Chengzhi

    2011-02-25

    We describe an effective approach for the covalent immobilization of antimicrobial peptides (AMPs) to bioinert substrates via Cu(I) -catalyzed azide-alkyne cycloaddition (CuAAC). The bioinert substrates were prepared by surface hydrosilylation of oligo(ethylene glycol) (OEG) terminated alkenes on hydrogen-terminated silicon surfaces. To render the OEG monolayers "clickable", mixed monolayers were prepared using OEG-alkenes with and without a terminal alkyne protected by a trimethylgermanyl (TMG) group. The mixed monolayers were characterized by X-ray photoelectron spectroscopy (XPS), elliposometry and contact angle measurement. The TMG protecting group can be readily removed to yield a free terminal alkyne by catalytic amounts of Cu(I) in an aqueous media. This step can then be combined with the subsequent CuAAC reaction. Thus, the immobilization of an azide modified AMP (N3-IG-25) was achieved in a one-pot deprotection/coupling reaction. Varying the ratio of the two alkenes in the deposition mixture allowed for control over the density of the alkynyl groups in the mixed monolayer, and subsequently the coverage of the AMPs on the monolayer. These samples allowed for study of the dependence of antimicrobial activities on the AMP density. The results show that a relative low coverage of AMPs (∼1.6×10(13) molecule per cm(2)) is sufficient to significantly suppress the viability of Pseudomonas aeruginosa, while the surface presenting the highest density of AMPs (∼2.8×10(13) molecule per cm(2)) is still cyto-compatible. The remarkable antibacterial activity is attributed to the long and flexible linker and the site-specific "click" immobilization, which may facilitate the covalently attached peptides to interact with and disrupt the bacterial membranes.

  4. Glyphosate degradation by immobilized bacteria: field studies with industrial wastewater effluent.

    PubMed

    Hallas, L E; Adams, W J; Heitkamp, M A

    1992-04-01

    Immobilized bacteria have been shown in the laboratory to effectively remove glyphosate from wastewater effluent discharged from an activated sludge treatment system. Bacterial consortia in lab columns maintained a 99% glyphosate-degrading activity (GDA) at a hydraulic residence time of less than 20 min. In this study, a pilot plant (capacity, 45 liters/min) was used for a field demonstration. Initially, activated sludge was enriched for microbes with GDA during a 3-week biocarrier activation period. Wastewater effluent was then spiked with glyphosate and NH4Cl and recycled through the pilot plant column during start-up. Microbes with GDA were enhanced by maintaining the pH at less than 8 and adding yeast extract (less than 10 mg/liter). Once the consortia were stabilized, the column capacity for glyphosate removal was determined in a 60-day continuous-flow study. Waste containing 50 mg of glyphosate per liter was pumped at increasing flow rates until a steady state was reached. A microbial GDA of greater than 90% was achieved at a 10-min hydraulic residence time (144 hydraulic turnovers per day). Additional studies showed that microbes with GDA were recoverable within (i) 5 days of an acid shock and (ii) 3 days after a 21-day dormancy (low-flow, low-maintenance) mode. These results suggest that full-scale use of immobilized bacteria can be a cost-effective and dependable technique for the biotreatment of industrial wastewater.

  5. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    NASA Astrophysics Data System (ADS)

    Dien To, Thien; Nguyen, Anh Tuan; Nhat Thanh Phan, Khoa; Thu Thi Truong, An; Doan, Tin Chanh Duc; Mau Dang, Chien

    2015-12-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES.

  6. Study on Carrier Material of Immobilization Acetylcholinesterase For Biosensor in Detectionof Organophosphorus Pesticide Residues

    NASA Astrophysics Data System (ADS)

    Sun, Xia; Wang, Xiangyou; Jia, Chuandong

    A comparison between several immobilization materials of AChE on surface of glassy carbon electrode(GCE) was presented. The immobilization methods employed crosslinking method with glutaraldehyde as a cross-linking agent and bovine serum albumin(BSA) as a protectant, AChE was immobilized on different membranes including nylon membrane, cellulose nitrate membrane and chitosan membrane respectively. The enzyme membrane was then fixed on the surface of glassy carbon electrode(GCE) with O-ring to prepare an amperometric biosensor for the detection of organophosphorus pesticides. The activity of immobilization AChE was detected by measuring the oxidation current of thiocholine, the results showed that the activity of immobilization AChE were all different with different membrane as carrier material.Compared with nylon membrane and cellulose nitrate membrane, chitosan membrane was obviously good. So chitosan membrane can be selected as immobilized AChE carrier material.

  7. Trypsin inhibitor screening in traditional Chinese medicine by using an immobilized enzyme microreactor in capillary and molecular docking study.

    PubMed

    Cheng, Mengxia; Chen, Zilin

    2017-08-01

    A trypsin immobilized enzyme microreactor was successfully prepared in capillary for studying enzyme kinetics of trypsin and online screening of trypsin inhibitors from traditional Chinese medicine through capillary electrophoresis. Trypsin was immobilized on the inner wall at the inlet of the capillary treated with polydopamine. The rest of the capillary was used as a separation channel. The parameters including the separation efficiency and the activity of immobilized trypsin were comprehensively evaluated. Under the optimal conditions, online screening of trypsin inhibitors each time can be carried out within 6 min. The Michaelis-Menten constant of immobilized trypsin was calculated to be 0.50 mM, which indicated high affinity of the immobilized trypsin for the substrate. The half-maximal inhibitory concentration of known inhibitor of benzamidine hydrochloride hydrate as a model inhibitor was 13.32 mM. The proposed method was successfully applied to screen trypsin inhibitors from 15 compounds of traditional Chinese medicine. It has been found that baicalin showed inhibitory potency. Molecular docking study well supported the experimental result by exhibiting molecular interaction between enzyme and inhibitors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Polymeric brushes as functional templates for immobilizing ribonuclease A: study of binding kinetics and activity.

    PubMed

    Cullen, Sean P; Liu, Xiaosong; Mandel, Ian C; Himpsel, Franz J; Gopalan, Padma

    2008-02-05

    The ability to immobilize proteins with high binding capacities on surfaces while maintaining their activity is critical for protein microarrays and other biotechnological applications. We employed poly(acrylic acid) (PAA) brushes as templates to immobilize ribonuclease A (RNase A), which is commonly used to remove RNA from plasmid DNA preparations. The brushes are grown by surface-anchored atom-transfer radical polymerization (ATRP) initiators. RNase A was immobilized by both covalent esterification and a high binding capacity metal-ion complexation method to PAA brushes. The polymer brushes immobilized 30 times more enzyme compared to self-assembled monolayers. As the thickness of the brush increases, the surface density of the RNase A increases monotonically. The immobilization was investigated by ellipsometry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The activity of the immobilized RNase A was determined using UV absorbance. As much as 11.0 microg/cm(2) of RNase A was bound to PAA brushes by metal-ion complexation compared to 5.8 microg/cm(2) by covalent immobilization which is 30 and 16 times the estimated mass bound in a monolayer. The calculated diffusion coefficient D was 0.63 x 10(-14) cm(2)/s for metal-ion complexation and 0.71 x 10(-14) cm(2)/s for covalent immobilization. Similar values of D indicate that the binding kinetics is similar, but the thermodynamic equilibrium coverage varies with the binding chemistry. Immobilization kinetics and thermodynamics were characterized by ellipsometry for both methods. A maximum relative activity of 0.70-0.80 was reached between five and nine monolayers of the immobilized enzyme. However, the relative activity for covalent immobilization was greater than that of metal-ion complexation. Covalent esterification resulted in similar temperature dependence as free enzyme, whereas metal-ion complexation showed no

  9. A comparative study for lipase immobilization onto alginate based composite electrospun nanofibers with effective and enhanced stability.

    PubMed

    İspirli Doğaç, Yasemin; Deveci, İlyas; Mercimek, Bedrettin; Teke, Mustafa

    2017-03-01

    In this study, lipase was successfully immobilized on polyvinyl alcohol/alginate and polyethylene oxide/alginate nanofibers that were prepared by electrospinning. Results showed that nanofibers (especially polyvinyl alcohol/alginate) enhanced the stability properties of lipase. When the free lipase lost its all activity after 40-60min at high temperatures, both lipase immobilized nanofibers kept almost 65-70% activity at the same time. The lipase immobilized poly vinyl alcohol/alginate and polyethylene oxide/alginate nanofibers protected approximately all of their activities until pH 9. Lipase immobilized polyvinyl alcohol/alginate and polyethylene oxide/alginate nanofibers maintained 60% of their activities after 14 and 7 reuses, respectively. The morphology of nanofibers was characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Thermal Gravimetric Analyzer. As a result, this nanofiber production method, electrospinning, is simple, versatile and economical for preparing appropriate carrier to immobilize the enzymes. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

    PubMed

    Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

    2016-09-01

    Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved.

  11. Instrumentation for studying binder burnout in an immobilized plutonium ceramic wasteform

    SciTech Connect

    Mitchell, M; Pugh, D; Herman, C

    2000-04-21

    The Plutonium Immobilization Program produces a ceramic wasteform that utilizes organic binders. Several techniques and instruments were developed to study binder burnout on full size ceramic samples in a production environment. This approach provides a method for developing process parameters on production scale to optimize throughput, product quality, offgas behavior, and plant emissions. These instruments allow for offgas analysis, large-scale TGA, product quality observation, and thermal modeling. Using these tools, results from lab-scale techniques such as laser dilametry studies and traditional TGA/DTA analysis can be integrated. Often, the sintering step of a ceramification process is the limiting process step that controls the production throughput. Therefore, optimization of sintering behavior is important for overall process success. Furthermore, the capabilities of this instrumentation allows better understanding of plant emissions of key gases: volatile organic compounds (VOCs), volatile inorganics including some halide compounds, NO{sub x}, SO{sub x}, carbon dioxide, and carbon monoxide.

  12. Spectroscopic study of 3-Hydroxyflavone - protein interaction in lipidic bi-layers immobilized on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Voicescu, Mariana; Ionescu, Sorana; Nistor, Cristina L.

    2017-01-01

    The interaction of 3-Hydroxyflavone with serum proteins (BSA and HSA) in lecithin lipidic bi-layers (PC) immobilized on silver nanoparticles (SNPs), was studied by fluorescence and Raman spectroscopy. BSA secondary structure was quantified with a deconvolution algorithm, showing a decrease in α-helix structure when lipids were added to the solution. The effect of temperature on the rate of the excited-state intra-molecular proton transfer and on the dual fluorescence emission of 3-HF in the HSA/PC/SNPs systems was discussed. Evaluation of the antioxidant activity of 3-HF in HSA/PC/SNPs systems was also studied. The antioxidant activity of 3-HF decreased in the presence of SNPs. The results are discussed with relevance to the secondary structure of proteins and of the 3-HF based nano-systems to a topical formulation useful in the oxidative stress process.

  13. Biosorption of metal contaminants using immobilized biomass: A laboratory study. Rept. of Investigations/1991

    SciTech Connect

    Jeffers, T.H.; Ferguson, C.R.; Bennett, P.G.

    1991-01-01

    The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials for removing metal contaminants from waste waters. The beads, designated as BIO-FIX beads, are prepared by blending biomass, such as sphagnum peat moss or algae, into a polymer solution and spraying the mixture into water. Laboratory studies were conducted to determine bead sorption and elution characteristics. Batch and continuous tests demonstrated that BIO-FIX beads sorbed arsenic, cadmium, lead, and other toxic metals from acid mine drainage waters collected from several sites. Selectivity for heavy and toxic metal ions over calcium and magnesium was demonstrated. The beads exhibited excellent metal sorption and handling characteristics in stirred tanks, column contactors, and a low-maintenance passive system. The sorption process was reversible, and metal ions were eluted from the beads using dilute mineral acids. Cyclic tests indicated that the beads continued to extract metal ions after repeated loading-elution cycles.

  14. Gold nanoworms immobilized graphene oxide polymer brush nanohybrid for catalytic degradation studies of organic dyes

    NASA Astrophysics Data System (ADS)

    Mogha, Navin Kumar; Gosain, Saransh; Masram, Dhanraj T.

    2017-02-01

    In the present work, we report gold nanoparticles (AuNPs) on poly (dimethylaminoethyl methacrylate) (PDMAEMA) brushes immobilized reduced graphene oxide (Au/PDMAEMA/RGO) as catalyst for degradation kinetic studies of Rhodamine B (RB), Methyl Orange (MO) and Eosine Y (EY) dyes, having an excellent catalytic activity, as evident by the apparent rate constant (kapp), which is found to be 21.8, 26.2, and 8.7 (×10-3 s-1), for RB, MO and EY respectively. Au/PDMAEMA/RGO catalyst is easy to use, highly efficient, recyclable, which make it suitable for applications in waste water management. Foremost, synthesis of PDMAEMA brushes on graphene oxide is accomplished by Atom transfer radical polymerization method (ATRP), whereas AuNPs are synthesized by simple chemical reduction method.

  15. Evaluation of capillary chromatographic supports for immobilized human purine nucleoside phosphorylase in frontal affinity chromatography studies.

    PubMed

    de Moraes, Marcela Cristina; Temporini, Caterina; Calleri, Enrica; Bruni, Giovanna; Ducati, Rodrigo Gay; Santos, Diógenes Santiago; Cardoso, Carmen Lucia; Cass, Quezia Bezerra; Massolini, Gabriella

    2014-04-18

    The aim of this work was to optimize the preparation of a capillary human purine nucleoside phosphorylase (HsPNP) immobilized enzyme reactor (IMER) for characterization and affinity screening studies of new inhibitors by frontal affinity chromatography coupled to mass spectrometry (FAC-MS). For this purpose two monolithic supports, a Chromolith Speed Rod (0.1mm I.D.×5cm) and a methacrylate-based monolithic epoxy polymeric capillary column (0.25mm I.D.×5cm) with epoxy reactive groups were considered and compared to an IMER previously developed using an open fused silica capillary. Each HsPNP-IMER was characterized in terms of catalytic activity using Inosine as standard substrate. Furthermore, they were also explored for affinity ranking experiments. Kd determination was carried out with the based fused silica HsPNP-IMER and the results are herein discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Microorganism immobilization

    DOEpatents

    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.

  17. Immobilization of DNA at Glassy Ccarbon Electrodes: A Critical Study of Adsorbed Layer

    PubMed Central

    Pedano, M. L.; Rivas, G. A.

    2005-01-01

    In this work we present a critical study of the nucleic acid layer immobilized at glassy carbon electrodes. Different studies were performed in order to assess the nature of the interaction between DNA and the electrode surface. The adsorption and electrooxidation of DNA demonstrated to be highly dependent on the surface and nature of the glassy carbon electrode. The DNA layer immobilized at a freshly polished glassy carbon electrode was very stable even after applying highly negative potentials. The electron transfer of potassium ferricyanide, catechol and dopamine at glassy carbon surfaces modified with thin (obtained by adsorption under controlled potential conditions) and thick (obtained by casting the glassy carbon surface with highly concentrated DNA solutions) DNA layers was slower than that at the bare glassy carbon electrode, although this effect was dependent on the thickness of the layer and was not charge selective. Raman experiments showed an important decrease of the vibrational modes assigned to the nucleobases residues, suggesting a strong interaction of these residues with the electrode surface. The hybridization of oligo(dG)21 and oligo(dC)21 was evaluated from the guanine oxidation signal and the reduction of the redox indicator Co(phen)33+. In both cases the chronopotentiometric response indicated that the compromise of the bases in the interaction of DNA with the electrode surface is too strong, preventing further hybridization. In summary, glassy carbon is a useful electrode material to detect DNA in a direct and very sensitive way, but not to be used for the preparation of biorecognition layers by direct adsorption of the probe sequence on the electrode surface for detecting the hybridization event.

  18. Useful oriented immobilization of antibodies on chimeric magnetic particles: direct correlation of biomacromolecule orientation with biological activity by AFM studies.

    PubMed

    Marciello, Marzia; Filice, Marco; Olea, David; Velez, Marisela; Guisan, José M; Mateo, Cesar

    2014-12-16

    The preparation and performance of a suitable chimeric biosensor based on antibodies (Abs) immobilized on lipase-coated magnetic particles by means of a standing orienting strategy are presented. This novel system is based on hydrophobic magnetic particles coated with modified lipase molecules able to orient and further immobilize different Abs in a covalent way without any previous site-selective chemical modification of biomacromolecules. Different key parameters attending the process were studied and optimized. The optimal preparation was performed using a controlled loading (1 nmol Ab g(-1) chimeric support) at pH 9 and a short reaction time to recover a biological activity of about 80%. AFM microscopy was used to study and confirm the Abs-oriented immobilization on lipase-coated magnetic particles and the final achievement of a highly active and recyclable chimeric immune sensor. This direct technique was demonstrated to be a powerful alternative to the indirect immunoactivity assay methods for the study of biomacromolecule-oriented immobilizations.

  19. A noble technique a using force-sensing resistor for immobilization-device quality assurance: A feasibility study

    NASA Astrophysics Data System (ADS)

    Cho, Min-Seok; Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Kim, Kyeong-Hyeon; Shin, Dong-Seok; Noh, Yu-Yun; Koo, Hyun-Jae; Cheon, Geum Seong; Suh, Tae Suk; Kim, Siyong

    2016-03-01

    Many studies have reported that a patient can move even when an immobilization device is used. Researchers have developed an immobilization-device quality-assurance (QA) system that evaluates the validity of immobilization devices. The QA system consists of force-sensing-resistor (FSR) sensor units, an electric circuit, a signal conditioning device, and a control personal computer (PC) with in-house software. The QA system is designed to measure the force between an immobilization device and a patient's skin by using the FSR sensor unit. This preliminary study aimed to evaluate the feasibility of using the QA system in radiation-exposure situations. When the FSR sensor unit was irradiated with a computed tomography (CT) beam and a treatment beam from a linear accelerator (LINAC), the stability of the output signal, the image artifact on the CT image, and changing the variation on the patient's dose were tested. The results of this study demonstrate that this system is promising in that it performed within the error range (signal variation on CT beam < 0.30 kPa, root-mean-square error (RMSE) of the two CT images according to presence or absence of the FSR sensor unit < 15 HU, signal variation on the treatment beam < 0.15 kPa, and dose difference between the presence and the absence of the FSR sensor unit < 0.02%). Based on the obtained results, we will volunteer tests to investigate the clinical feasibility of the QA system.

  20. Study on the biodegradation of crude oil by free and immobilized bacterial consortium in marine environment

    PubMed Central

    Li, Jingjing; Liu, Mei; Sun, Huiling; Bao, Mutai

    2017-01-01

    Five strains of bacteria, namely, Exiguobacterium sp. ASW-1, Pseudomonas aeruginosa strain ASW-2, Alcaligenes sp. ASW-3, Alcaligenes sp. ASS-1, and Bacillus sp. ASS-2, were isolated from the Zhejiang coast in China. The mixed flora of the five strains performed well with degrading 75.1% crude oil (1%, w/v) in 7 days. The calcium alginate—activated carbon embedding carrier was used to immobilize bacterial consortium. Immobilized cells performed better than free ones in variations of environmental factors containing incubated temperature, initial pH, salinity of the medium and crude oil concentration. The degradation process of crude oil by immobilized bacteria was accelerated compared with that of the free ones. Bacterial consortium showed better performance on biodegradation of normal alkanes than that of PAHs. Improvement of immobilization on the biodegradation efficiency of normal alkanes (31.9%) was apparently high than that of PAHs (1.9%). PMID:28346510

  1. Study on the biodegradation of crude oil by free and immobilized bacterial consortium in marine environment.

    PubMed

    Chen, Qingguo; Li, Jingjing; Liu, Mei; Sun, Huiling; Bao, Mutai

    2017-01-01

    Five strains of bacteria, namely, Exiguobacterium sp. ASW-1, Pseudomonas aeruginosa strain ASW-2, Alcaligenes sp. ASW-3, Alcaligenes sp. ASS-1, and Bacillus sp. ASS-2, were isolated from the Zhejiang coast in China. The mixed flora of the five strains performed well with degrading 75.1% crude oil (1%, w/v) in 7 days. The calcium alginate-activated carbon embedding carrier was used to immobilize bacterial consortium. Immobilized cells performed better than free ones in variations of environmental factors containing incubated temperature, initial pH, salinity of the medium and crude oil concentration. The degradation process of crude oil by immobilized bacteria was accelerated compared with that of the free ones. Bacterial consortium showed better performance on biodegradation of normal alkanes than that of PAHs. Improvement of immobilization on the biodegradation efficiency of normal alkanes (31.9%) was apparently high than that of PAHs (1.9%).

  2. [Study of the interaction of main potato glycoalkaloids in inhibition of immobilized butyryl cholinesterase].

    PubMed

    Arkhypova, V M; Dziadevych, S V; Jaffrezic-Renault, N; Martelet, C; Soldatkin, O P

    2006-01-01

    The interaction of main potato glycoalkaloids alpha-solanine and alpha-chaconine in inhibition of horse serum butyryl cholinesterases immobilized on the pH-sensitive field-effect transistors has been investigated. The method of isobol diagram of Loewe and Muishnek has been used for interpretation of results. It has been shown the alpha-chaconine inhibits the immobilized bytyryl cholinesterases more strongly than alpha-solanine, and their mixture has the addition effect.

  3. Plutonium Immobilization Project Binder Burnout and Sintering Studies (Milestone 6.6a)

    SciTech Connect

    Chandler, G.

    1999-10-28

    The Plutonium Immobilization Team has developed an integrated test program to understand and optimize the controlling variables for the sintering step of the plutonium immobilization process. Sintering is the key process step that controls the product minerology. It is expected that the sintering will be the limiting process step that controls the throughput of the production line. The goal of the current sintering test program is to better understand factors that affect the sintering process.

  4. Immobilization of flavan-3-ols onto sensor chips to study their interactions with proteins and pectins by SPR

    NASA Astrophysics Data System (ADS)

    Watrelot, Aude A.; Tran, Dong Tien; Buffeteau, Thierry; Deffieux, Denis; Le Bourvellec, Carine; Quideau, Stéphane; Renard, Catherine M. G. C.

    2016-05-01

    Interactions between plant polyphenols and biomacromolecules such as proteins and pectins have been studied by several methods in solution (e.g. isothermal titration calorimetry, dynamic light scattering, nuclear magnetic resonance and spectrophotometry). Herein, these interactions were investigated in real time by Surface Plasmon Resonance (SPR) analysis after immobilization of flavan-3-ols onto a sensor chip surface. (-)-epicatechin, (+)-catechin and flavan-3-ol oligomers with an average degree of polymerization of 2 and 8 were chemically modified using N-(2-(tritylthio)ethyl)propiolamide in order to introduce a spacer unit onto the catecholic B ring. Modified flavan-3-ols were then immobilized onto a carboxymethylated dextran surface (CM5). Immobilization was validated and further verified by evaluating flavan-3-ol interaction with bovine serum albumin (BSA), poly-L-proline or commercial pectins. BSA was found to have a stronger association with monomeric flavan-3-ols than oligomers. SPR analysis of selected flavan-3-ols immobilized onto CM5 sensor chips showed a stronger association for citrus pectins than apple pectins, regardless of flavan-3-ol degree of polymerization.

  5. Biosorption of Cu(II) by immobilized microalgae using silica: kinetic, equilibrium, and thermodynamic study.

    PubMed

    Lee, Hongkyun; Shim, Eunjung; Yun, Hyun-Shik; Park, Young-Tae; Kim, Dohyeong; Ji, Min-Kyu; Kim, Chi-Kyung; Shin, Won-Sik; Choi, Jaeyoung

    2016-01-01

    Immobilized microalgae using silica (IMS) from Micractinium reisseri KGE33 was synthesized through a sol-gel reaction. Green algal waste biomass, the residue of M. reisseri KGE33 after oil extraction, was used as the biomaterial. The adsorption of Cu(II) on IMS was tested in batch experiments with varying algal doses, pH, contact times, initial Cu(II) concentrations, and temperatures. Three types of IMSs (IMS 14, 70, and 100) were synthesized according to different algal doses. The removal efficiency of Cu(II) in the aqueous phase was in the following order: IMS 14 (77.0%) < IMS 70 (83.3%) < IMS 100 (87.1%) at pH 5. The point of zero charge (PZC) value of IMS100 was 4.5, and the optimum pH for Cu(II) adsorption was 5. Equilibrium data were described using a Langmuir isotherm model. The Langmuir model maximum Cu(II) adsorption capacity (q m) increased with the algal dose in the following order: IMS 100 (1.710 mg g(-1)) > IMS 70 (1.548 mg g(-1)) > IMS 14 (1.282 mg g(-1)). The pseudo-second-order equation fitted the kinetics data well, and the value of the second-order rate constant increased with increasing algal dose. Gibbs free energies (ΔG°) were negative within the temperature range studied, which indicates that the adsorption process was spontaneous. The negative value of enthalpy (ΔH°) again indicates the exothermic nature of the adsorption process. In addition, SEM-energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses of the IMS surface reveal that the algal biomass on IMS is the main site for Cu(II) binding. This study shows that immobilized microalgae using silica, a synthesized biosorbent, can be used as a cost-effective sorbent for Cu(II) removal from the aqueous phase.

  6. Effects of Right Lower Limb Orthopedic Immobilization on Braking Function: An On-The-Road Experimental Study With Healthy Volunteers.

    PubMed

    Murray, Jean-Christophe; Tremblay, Marc-André; Corriveau, Hélène; Hamel, Mathieu; Cabana, François

    2015-01-01

    Little is known about how immobilization of the right lower limb might affect driving. The purpose of the present study was to evaluate the effect of 2 types of immobilization on the emergency braking time of healthy subjects during actual driving conditions. The emergency braking times of 14 healthy volunteers were assessed in a closed circuit under 3 conditions: wearing running shoes, wearing an Aircast Walker(®), or wearing a walking cast on their right lower limb. An instrumented car was used to measure the emergency braking times during braking tests with and without a distractor. The foot movement times were significantly increased with both immobilization devices compared with the running shoe (p < .01). The median total braking time with the running shoe during emergency braking without a distractor was 0.452 (interquartile range, 25th to 75th [IQR], 0.413 to 0.472) second. The results obtained with the Aircast Walker(®) or the walking cast were significantly longer (p < .01), at 0.480 (IQR, 0.431 to 0.537) second and 0.512 (IQR, 0.451 to 0.535) second, respectively. When a distractor was added, the total braking time with the running shoe, Aircast Walker(®), and walking cast was 0.489 (IQR, 0.429 to 0.575), 0.516 (IQR, 0.459 to 0.586), and 0.510 (IQR, 0.469 to 0.570) second, respectively, with no statistically significant differences among these 3 conditions. Wearing an immobilization device on the right lower limb minimally lengthens the emergency braking time in healthy drivers under actual driving conditions. Clinicians must nonetheless exercise caution when advising a driver wearing an orthopedic immobilization, because driving a motor vehicle is a complex psychomotor task that goes well beyond the emergency braking time.

  7. Study the biocatalyzing effect and mechanism of cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification.

    PubMed

    Li, Haibo; Guo, Jianbo; Lian, Jing; Xi, Zhenhua; Zhao, Lijun; Liu, Xiaoyu; Zhang, Chenxiao; Yang, Jingliang

    2014-06-01

    The biocatalyzing effect of a novel cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification process was studied with anthraquinone, 1,8-dichloroanthraquinone, 1,5-dichloroanthraquinone and 1,4,5,8-tetrachloroanthraquinone. The results showed that the immobilized 1,4,5,8-tetrachloroanthraquinone presented the best biocatalyzed effect which increased nitrite denitrification rate to 2.3-fold with 12 mmol/L 1,4,5,8-tetrachloroanthraquinone. The unequal biocatalyzing effect was due to the quantity and position of -Cl substituent in anthraquinone-structure. Moreover, the nitrite denitrification rate was increased with the oxidation reduction potential (ORP) values becoming more negative during the biocatalyzing process. The stabilized ORP value with 12 mmol/L immobilized 1,4,5,8-tetrachloroanthraquinone were 81 mV lower than the control. At the same time, the more OH(-) was produced with the higher nitrite removal rate achieved in the nitrite denitrification process. In addition, a positive linear correlation was found between the nitrite removal reaction constants k [gNO2(-)-N/(gVSS d)] and immobilized 1,4,5,8-tetrachloroanthraquinone concentration (C1,4,5,8-tetrachloroanthraquinone), which was k = 1.8443 C1,4,5,8-tetrachloroanthraquinone + 33.75(R(2) = 0.9411). The initial nitrite concentration of 179 mgNO2(-)-N/L resulted in the maximum nitrite removal rate, which was 6.526[gNO2(-)-N/(gVSS d)]. These results show that the application of cellulose acetate immobilized redox mediators (CE-RM) can be valuable for increasing nitrite denitrification rate.

  8. Sonoenzymatic decolourization of an azo dye employing immobilized horse radish peroxidase (HRP): a mechanistic study.

    PubMed

    Malani, Ritesh S; Khanna, Swati; Moholkar, Vijayanand S

    2013-07-15

    For degradation of biorefractory pollutants, enzymatic treatments and sonochemical treatments have shown high potential. A combined technique of sono-enzymatic treatment is of special interest as it has shown enhancement effect than the individual techniques. This work has attempted to give a mechanistic insight into the interaction of sonochemical and enzymatic treatments using immobilized horseradish peroxidase (HRP) enzyme on the decolourization of acid red dye (an azo dye). In order to segregate the effect of ultrasound and cavitation, experiments were conducted at elevated static pressure. The kinetic parameters of HRP, viz. Vmax and Km were marginally affected by immobilization. There was a minor change in pH optima and temperature optima for immobilized HRP (6.5, 25°C) from free HRP (7.0, 20-25°C). Though the specific activity of free enzyme (0.272U/mg) was found to be higher than the immobilized enzyme (0.104U/mg), immobilized enzyme exhibited higher stability (up to 3 cycles) and degradation potential than free enzyme in all experiments. The results revealed that the coupling of sonication and enzymatic treatment at high pressure in presence of polyethylene glycol (PEG) yielded the highest decolourization of acid red (61.2%). However, the total decolourization achieved with combined technique was lesser than the sum of individual techniques, indicating negative synergy between the sonochemical and enzymatic techniques.

  9. Comparative study of microcapsules elaborated with three polycations (PLL, PDL, PLO) for cell immobilization.

    PubMed

    De Castro, M; Orive, G; Hernández, R M; Gascón, A R; Pedraz, J L

    2005-05-01

    Alginate-poly-L-lysine (PLL)-alginate microcapsules have been widely used in cell microencapsulation technology. However, the mechanical fragility and low tensile resistance against swelling of this membrane chemistry and the difficult handling, immunogenicity and cytotoxicity of PLL have stimulated the study of novel polycations. In this paper, alginate microcapsules coated with three different polycations: poly-L-lysine (PLL), poly-D-lysine (PDL) and poly-L-ornithine (PLO) were fabricated to evaluate if the use of novel membrane chemistries (PDL, PLO) had a positive effect on the morphology, osmotic resistance and mechanical stability of the capsules as well as the viability of the immobilized C2C12 myoblast cells when compared to the classical PLL microcapsules. Results indicate that liquefied capsules presented worse mechanical properties than the polymerized solid capsules in the three type of membrane chemistries. In addition, PLL membrane chemistry exerted the highest resistance against compressions after culture in several mediums, while PDL microcapsules showed the highest resistance to the tensile stress of the osmotic pressure. No important differences were detected when the physiological activity of the enclosed cells was evaluated. In summary, although further in vivo assays are needed, in general none of the new membrane formulations represented a significant improvement over classical PLL microcapsules.

  10. Kinetic study of biodegradation of BTX compounds in mono- and multicomponent systems in reactor with immobilized biomass.

    PubMed

    Mayer, D A; de Souza, A A Ulson; Fontana, E; de Souza, S M A Ulson

    2016-09-01

    In this study, kinetic parameters were determined for the biodegradation of BTX compounds in a fixed-bed reactor with immobilized biomass, fed with mono- and multicomponent systems. The parameter estimation was achieved through an algorithm using the finite volume method. Different kinetic models were evaluated. The Monod model proved to be suitable to predict the experimental data for the biodegradation individual BTX compound. In multicomponent systems, it was found that the presence of more than one compound tends to cause competitive inhibition. To identify the models that best fit the experimental data, a statistical analysis using the F test was applied. For the two- and three-component systems the presence of more than one compound tends to cause competitive inhibition. In this study, it was possible to predict kinetic parameters in mono- and multicomponent systems as well as different operation conditions for a fixed-bed reactor with immobilized biomass.

  11. A kinetic study on the bioremediation of sodium cyanide and acetonitrile by free and immobilized cells of pseudomonas putida

    SciTech Connect

    Chapatwala, K.D.; Babu, G.R.V.; Armstead, E.R.

    1995-12-31

    Pseudomonas putida capable of utilizing organic nitrile (acetonitrile) and inorganic cyanide (sodium cyanide) as the sole source of carbon and nitrogen was isolated from contaminated industrial sites and waste water. The bacterium possesses nitrile aminohydrolase (EC 3.5.5.1) and amidase (EC 3.5.1.4), which are involved in the transformation of cyanides and nitrites into ammonia and CO{sub 2} through the formation of amide as an intermediate. Both of the enzymes have a high selectivity and affinity toward the {sup -}CN group. The rate of degradation of acetonitrile and sodium cyanide to ammonia and CO{sub 2} by the calcium-alginate immobilized cells of P. putida was studied. The rate of reaction during the biodegradation of acetonitrile and sodium cyanide, and the substrate- and product-dependent kinetics of these toxic compounds were studied using free and immobilized cells of P. putida and modeled using a simple Michaelis-Menten equation.

  12. Sequential injection affinity chromatography utilizing an albumin immobilized monolithic column to study drug-protein interactions.

    PubMed

    Zacharis, Constantinos K; Kalaitzantonakis, Eftichios A; Podgornik, Ales; Theodoridis, Georgios

    2007-03-09

    In this study, sequential injection affinity chromatography was used for drug-protein interactions studies. The analytical system used consisted of a sequential injection analysis (SIA) manifold directly connected with convective interaction media (CIM) monolithic epoxy disks modified by ligand-immobilization of protein. A non-steroidal, anti-inflammatory drug, naproxen (NAP) and bovine serum albumin (BSA) were selected as model drug and protein, respectively. The SIA system was used for sampling, introduction and propulsion of drug towards to the monolithic column. Association equilibrium constants, binding capacity at various temperatures and thermodynamic parameters (free energy DeltaG, enthalpy DeltaH) of the binding reaction of naproxen are calculated by using frontal analysis mathematics. The variation of incubation time and its effect in on-line binding mode was also studied. The results indicated that naproxen had an association equilibrium constant of 2.90 x 10(6)M(-1) at pH 7.4 and 39 degrees C for a single binding site. The associated change in enthalpy (DeltaH) was -27.36 kcal mol(-1) and the change in entropy (DeltaS) was -73 cal mol(-1)K(-1) for a single type of binding sites. The location of the binding region was examined by competitive binding experiments using a biphosphonate drug, alendronate (ALD), as a competitor agent. It was found that the two drugs occupy the same class of binding sites on BSA. All measurements were performed with fluorescence (lambda(ext)=230 nm, lambda(em)=350 nm) and spectrophotometric detection (lambda=280 nm).

  13. Immobilization of Cd in landfill-leachate-contaminated soil with cow manure compost as soil conditioners: A laboratory study.

    PubMed

    Liao, Zhuwei; Wang, Jia; Wan, Rui; Xi, Shuang; Chen, Zhuqi; Chen, Zhulei; Yu, Yingjian; Long, Sijie; Wang, Huabin

    2016-12-01

    Introducing cow manure compost as an amendment in landfill-leachate-contaminated soils is proved to be an effective technique for the immobilization of Cd in this study. Landfill-leachate-contaminated soil was collected from an unlined landfill in China and amended with a different blending quantity of cow manure compost (0, 12, 24, 36, and 48 g per 200 g soil), which was made by mixing cow manure and chaff at a ratio of 1/1 and maturing for 6 months. pH values of five different blending quantity mixtures increased by 0.2-0.4, and the organic matter levels increased by 2.5-7%, during a remediation period of 5 weeks. Four fractions of Cd named exchangeable Cd, reducible Cd, oxidizable Cd, and residual Cd in soil were respectively analyzed by a sequential extraction procedure. Introducing the cow manure compost application resulted in more than 40% lower exchangeable Cd but a higher concentration of oxidizable Cd in soils, and mass balance results showed nearly no Cd absorption by applied material, indicating that transformation of exchangeable Cd into oxidization forms was the main mechanism of Cd immobilization when cow manure compost was used as an amendment. The Pearson correlation showed that increasing of pH values significantly improved the efficiency of Cd immobilization, with a correlation coefficiency of 0.940 (p < 0.05). This is the first attempt at heavy metal immobilization in landfill-leachate-contaminated soil by cow manure compost, and findings of this work can be integrated to guide the application. Addition of cow manure compost (CMC) was effective in reducing exchangeable Cd in landfill-leachate-contaminated soils (LLCS). The immobilization effect of Cd was mainly assigned to the redistribution of labile soil Cd. Organic matter (OM) and pH value increased with CMC application. The pH values were more sensitive to Cd immobilization efficiency. It was proved that CMC can be safely and effectively used for the restoration of LLCS.

  14. Physical and chemical immobilization of choline oxidase onto different porous solid supports: Adsorption studies.

    PubMed

    Passos, Marieta L C; Ribeiro, David S M; Santos, João L M; Saraiva, M Lúcia M F S

    2016-08-01

    This work carries out for the first time the comparison between the physical and chemical immobilization of choline oxidase onto aminated silica-based porous supports. The influence on the immobilization efficiency of concentration, pH, temperature and contact time between the support and choline oxidase, was evaluated. The immobilization efficiency was estimated taking into consideration the choline oxidase activity, which was assessed by using cadmium telluride (CdTe) quantum dots (QDs), obtained by hydrothermal synthesis, as photoluminescent probes. Hydrogen peroxide produced by enzyme activity was capable of quenching CdTe QDs photoluminescence. The magnitude of the PL quenching process was directly related with the enzyme activity. By comparing the chemical process with the physical adsorption, it was observed that the latter provided the highest choline oxidase immobilization. The equilibrium data were analyzed using Langmuir and Freundlich isotherms and kinetic data were fitted to the pseudo-first-order and pseudo-second-order models. Thermodynamic parameters, such as Gibbs free energy and entropy were also calculated. These results will certainly contribute to the development of new sensing schemes for choline, taking into account the growing demand for its quantification in biological samples.

  15. Study on contraction and relaxation of experimentally denervated and immobilized muscles: Comparison with dystrophic muscles

    NASA Technical Reports Server (NTRS)

    Takamori, M.; Tsujihata, M.; Mori, M.; Hazama, R.; Ide, Y.

    1980-01-01

    The contraction-relaxation mechanism of experimentally denervated and immobilized muscles of the rabbit is examined. Results are compared with those of human dystrophic muscles, in order to elucidate the role and extent of the neurotrophic factor, and the role played by the intrinsic activity of muscle in connection with pathogenesis and pathophysiology of this disease.

  16. An Experimental Study of Sand Transport over an Immobile Gravel Substrate

    USDA-ARS?s Scientific Manuscript database

    The effects of a stepwise addition of sand to an immobile gravel bed on the sand transport rate and configuration of the sand bed was investigated in a laboratory flume channel. Detailed measurements of sand transport rate, bed texture, and bed topography were collected for four different discharge...

  17. Studies on immobilized Saccharomyces cerevisiae. III. Physiology of growth and metabolism on various supports

    SciTech Connect

    Bandyopadhyay, K.K.; Ghose, T.K.

    1982-04-01

    In earlier communications general analyses of rapid ethanol fermentation by Saccharomyces cerevisiae immobilized on inert supports were described. In this article physiology of growth and metabolism (parameters like rates of CO/sub 2/ evolution and O/sub 2/ uptake, respiratory quotient, and generation time) of Saccharomyces cerevisiae immobilized on different supports are reported. Values of the ratio of specific oxygen uptake rate for immobilized cells to free cells have been found to be 0.732, 0.781, and 0.785 for carrier A, carrier B, and covalently crosslinked controlled pore glass (CPG, specific surface area of 439 m/sup 2/ g/sup -1/), respectively. Rates of specific CO/sub 2/ evolution for immobilized cells to free cells for these supports are 0.784, 0.822, and 0.783, respectively. Marked reduction in generation time of Saccharomyces cerevisiae on all the supports has been observed. No change in size (4.8-5 ..mu..m) and specific growth rate (..mu../sub m/ = 0.275 h/sup -1/) of cells leaving the reactor has been observed.

  18. Cervical spine immobilization in sports related injuries: review of current guidelines and a case study of an injured athlete.

    PubMed

    Bhamra, Js; Morar, Y; Khan, Ws; Deep, K; Hammer, A

    2012-01-01

    Cervical spine immobilization is an essential component of the ATLS(®) system. Inadequate training in the management of trauma calls and failure of early recognition can have disastrous consequences. Pre-hospital personnel are routinely involved more in the assessment and stabilization of patients in comparison to other health care professionals.This case study and review highlights the importance of early recognition, assessment and correct stabilization of cervical spine injuries both in the field and during the initial assessment in hospital.Inadequate assessment, immobilization and lack of standard guidelines on the management of suspected cervical spine trauma can result in secondary injury. Regular assessment and training of pre-hospital and medical personnel is essential to the proper management of these potentially devastating injuries.

  19. Studies on immobilized Saccharomyces cerevisiae. II. Effect of temperature distribution on continuous rapid ethanol formation in molasses fermentation.

    PubMed

    Ghose, T K; Bandyopadhyay, K K

    1982-04-01

    Recently, considerable interest has been shown in the study and analysis of immobilized cell reactors. One of the major uses of such a reactor system is expected to be in ethanol production from carbohydrates. One distinct disadvantage of this system is carbon dioxide gas holdup associated with unsteady-state temperature distribution across the reactor. Taking into account the earlier published data and assuming steady-state-substrate balance, and unsteady-state energy balance, and an average gas holdup of 20% with the heat retained by the gas neglected, the average reaction rate in the differential element was computed. Finally, a mathematical model to predict steady-state temperature profile along the reactor was developed. It was verified with experimental data obtained from an immobilized yeast reactor column (1 m x 14.5 cm). The experimental data fit well those computed from the model within an accuracy of 5%.

  20. Cervical Spine Immobilization in Sports Related Injuries: Review of Current Guidelines and a Case Study of an Injured Athlete

    PubMed Central

    Bhamra, JS; Morar, Y; Khan, WS; Deep, K; Hammer, A

    2012-01-01

    Cervical spine immobilization is an essential component of the ATLS® system. Inadequate training in the management of trauma calls and failure of early recognition can have disastrous consequences. Pre-hospital personnel are routinely involved more in the assessment and stabilization of patients in comparison to other health care professionals. This case study and review highlights the importance of early recognition, assessment and correct stabilization of cervical spine injuries both in the field and during the initial assessment in hospital. Inadequate assessment, immobilization and lack of standard guidelines on the management of suspected cervical spine trauma can result in secondary injury. Regular assessment and training of pre-hospital and medical personnel is essential to the proper management of these potentially devastating injuries. PMID:23248726

  1. Antagonism of Gluconacetobacter diazotrophicus (a sugarcane endosymbiont) against Xanthomonas albilineans (pathogen) studied in alginate-immobilized sugarcane stalk tissues.

    PubMed

    Blanco, Yolanda; Blanch, María; Piñón, Dolores; Legaz, María-Estrella; Vicente, Carlos

    2005-04-01

    Xanthomonas albilineans, a pathogenic bacterium that produces leaf scald disease of sugarcane, secretes a xanthan-like gum that invades both xylem and phloem of the host. Xanthan production has been verified after experimental infection of stalk segments of healthy plants. Moreover, Gluconacetobacter diazotrophicus is a nitrogen-fixing endosymbiont of sugarcane plants that antagonizes with X. albilineans by impeding the production of the bacterial gum. The physiological basis of this antagonism has been studied using tissues of sugarcane stalks previously inoculated with the endosymbiont, then immobilized in calcium alginate and maintained in a culture medium for Gluconacetobacter. Under these conditions, bacteria infecting immobilized tissues are able to secrete to the medium a lysozyme-like bacteriocin that inhibits the growth of X. albilineans.

  2. Study of reaction parameters and kinetics of esterification of lauric acid with butanol by immobilized Candida antarctica lipase.

    PubMed

    Shankar, Sini; Agarwal, Madhu; Chaurasia, S P

    2013-12-01

    Esterification of lauric acid with n-butanol, catalyzed by immobilized Candida antarctica lipase (CAL) in aqueous-organic biphasic solvent system was studied. Effects of various reaction parameters on esterification were investigated, such as type and amount of solvent, amount of buffer, pH, temperature, speed of agitation, amount of enzyme, butanol and lauric acid. The most suitable reaction conditions for esterification were observed at 50 degrees C and pH 7.0 using 5000 micromoles of lauric acid, 7000 pmoles of butanol, 0.25 ml phosphate buffer, 1 ml of isooctane as the solvent and 50 mg of immobilized enzyme in the reaction medium at agitation speed of 150 rpm. Maximum esterification of 96.36% was acheived in 600 min of reaction time at n-butanol to lauric acid molar ratio of 1: 0.7. Kinetic study for the esterification of lauric acid with n-butanol using immobilized CAL was carried out and the kinetic constants were estimated by using non-linear regression method. The estimated value of Michaelis kinetic constants for butanol (KmBt) and acid (KmAc) were 451.56 (M) and 4.7 x 10(-7)(M), respectively and the value of dissociation constant (KBt) of the butanol-lipase complex was 9.41 x 10(7)(M). The estimated constants agreed fairly well with literature data.

  3. Thermodynamic study of an unusual chiral separation. Propranolol enantiomers on an immobilized cellulase

    SciTech Connect

    Fornstedt, T.; Sajonz, P.; Guiochon, G. |

    1997-02-12

    The thermodynamics of interaction of (R)- and (S)-propranolol between an acetic acid buffer (pH = 4.7 and 5.5) and the protein cellobiohydrolase I immobilized on silica gel was studied between 5 and 45{degree}C. The equilibrium data were fitted to a biLangmuir adsorption isotherm with excellent agreement. One of the two Langmuir contributions is the same for both enantiomers and accounts for the nonspecific interactions between these compounds and most sites on the surfaces (type-I, nonselective sites). It has a large saturation capacity. The second contribution accounts for the chiral selective interactions (type-II sites). It has a lower monolayer capacity than the first. The interaction enthalpy and entropy on type-I sites are -1.1 kcal/mol and +0.1 cal/(mol K), respectively. For type-II sites, they are -1.9 kcal/mol and -2.6 cal/(mol K), respectively, for (R)-propranolol and +1.6 kcal/mol and +11.6 cal/(mol K), respectively, for (S)-propranolol at pH = 5.5. This explains why at this pH the retention time of the less-retained R enantiomer decreases with increasing temperature, while the retention time of the S enantiomer increases, causing a large increase of the separation factor when the temperature is raised from 5 to 45{degree}C. The saturation capacity of the chiral contributions depends strongly on the pH, and the retention times of both enantiomers decrease with increasing temperature at pH = 4.7. 46 refs., 6 figs., 5 tabs.

  4. Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.

    PubMed

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2014-12-26

    In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time.

  5. Differential effect of the shape of calcium alginate matrices on the physiology of immobilized neuroblastoma N2a and Vero cells: a comparative study.

    PubMed

    Kintzios, S; Yiakoumetis, I; Moschopoulou, G; Mangana, O; Nomikou, K; Simonian, A

    2007-11-30

    In order to investigate the effect of cell immobilization in calcium alginate gels on cell physiology, we immobilized Vero or N2a neuroblastoma cells in gels shaped either as spherical beads or as thin membrane layers. Throughout a culture period of 4 weeks cell viability, RNA and cytoplasmic calcium concentration and glutathione accumulation were assayed by fluorescence microscopy after provision of an appropriate dye. Non-elaborate culture conditions were applied throughout the experimental period in order to evaluate cell viability under less than optimal storage conditions. Vero cell proliferation was observed only in spherical beads, while N2a cell proliferation was observed in both configurations until the third week of culture. Increased [Ca2+]cyt could be associated with cell proliferation only when cells were immobilized in spherical beads, while a considerable decrease in the biosynthesis of reduced glutathione and RNA was observed in cells immobilized in thin membrane layers. The observed effects of the shape of the immobilization matrix may be due to differences in external mass transfer resistance. Therefore, depending on cell type, cell proliferation could have been promoted by either increased (Vero) or decreased (N2a) nutrient and oxygen flow to immobilized cells. The results of the present study could contribute to an improvement of immobilized cell sensor storability.

  6. PRELIMINARY STUDY OF CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

    SciTech Connect

    Fox, K.; Billings, A.; Brinkman, K.; Marra, J.

    2010-09-22

    The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los

  7. Uranium Immobilization through Fe(II) bio-oxidation: A Column study

    SciTech Connect

    Coates, John D.

    2009-09-14

    Current research on the bioremediation of heavy metals and radionuclides is focused on the ability of reducing organisms to use these metals as alternative electron acceptors in the absence of oxygen and thus precipitate them out of solution. However, many aspects of this proposed scheme need to be resolved, not the least of which is the time frame of the treatment process. Once treatment is complete and the electron donor addition is halted, the system will ultimately revert back to an oxic state and potentially result in the abiotic reoxidation and remobilization of the immobilized metals. In addition, the possibility exists that the presence of more electropositive electron acceptors such as nitrate or oxygen will also stimulate the biological oxidation and remobilization of these contaminants. The selective nitrate-dependent biooxidation of added Fe(II) may offer an effective means of “capping off” and completing the attenuation of these contaminants in a reducing environment making the contaminants less accessible to abiotic and biotic reactions and allowing the system to naturally revert to an oxic state. Our previous DOE-NABIR funded studies demonstrated that radionuclides such as uranium and cobalt are rapidly removed from solution during the biogenic formation of Fe(III)-oxides. In the case of uranium, X-ray spectroscopy analysis indicated that the uranium was in the hexavalent form (normally soluble) and was bound to the precipitated Fe(III)-oxides thus demonstrating the bioremediative potential of this process. We also demonstrated that nitrate-dependent Fe(II)- oxidizing bacteria are prevalent in the sediment and groundwater samples collected from sites 1 and 2 and the background site of the NABIR FRC in Oakridge, TN. However, all of these studies were performed in batch experiments in the laboratory with pure cultures and although a significant amount was learned about the microbiology of nitrate-dependent bio-oxidation of Fe(II), the effects of

  8. Immobilization of proteins on boron nitride nanotubes.

    PubMed

    Zhi, Chunyi; Bando, Yoshio; Tang, Chengchun; Golberg, Dmitri

    2005-12-14

    We report for the first time that proteins are immobilized on boron nitride nanotubes. It is found that there is a natural affinity of a protein to BNNT; this means that it can be immobilized on BNNT directly, without usage of an additional coupling reagent. For the most effective immobilization, noncovalently functionalized BNNTs should be used. The effect of immobilization was studied using high-resolution transmission electron microscopy and energy dispersion spectroscopy.

  9. Integrated immobilized cell reactor-adsorption system for beta-cyclodextrin production: a model study using PVA-cryogel entrapped Bacillus agaradhaerens cells.

    PubMed

    Martins, Rita F; Plieva, Fatima M; Santos, Ana; Hatti-Kaul, Rajni

    2003-09-01

    Production of cyclodextrins (CDs) by immobilized cells of the alkaliphilic Bacillus agaradhaerens LS-3C with integrated product recovery was studied. The microorganism was entrapped in polyvinyl alcohol-cryogel beads and used as a convenient source of immobilized cyclodextrin glycosyltransferase (CGTase). On activation by incubation in the cultivation medium containing 1% (w/v) starch, the entrapped cells multiplied and secreted CGTase with an activity of 2-3 mg beta-cyclodextrin h(-1) g(-1) beads. The immobilized biocatalyst exhibited maximum activity at pH 9 and 50 degrees C, and formed cyclodextrins comprising 92-94% beta-CD and remaining alpha-CD. The cyclodextrin product from the immobilized cell bioreactor was continuously recovered by adsorption to Amberlite XAD-4 in a recycle batch mode. The product adsorption was facilitated at low temperature while hot water was used for elution.

  10. Study on Different Molecular Weights of Chitosan as an Immobilization Matrix for a Glucose Biosensor

    PubMed Central

    Ang, Lee Fung; Por, Lip Yee; Yam, Mun Fei

    2013-01-01

    Two chitosan samples (medium molecular weight (MMCHI) and low molecular weight (LMCHI)) were investigated as an enzyme immobilization matrix for the fabrication of a glucose biosensor. Chitosan membranes prepared from acetic acid were flexible, transparent, smooth and quick-drying. The FTIR spectra showed the existence of intermolecular interactions between chitosan and glucose oxidase (GOD). Higher catalytic activities were observed on for GOD-MMCHI than GOD-LMCHI and for those crosslinked with glutaraldehyde than using the adsorption technique. Enzyme loading greater than 0.6 mg decreased the activity. Under optimum conditions (pH 6.0, 35°C and applied potential of 0.6 V) response times of 85 s and 65 s were observed for medium molecular weight chitosan glucose biosensor (GOD-MMCHI/PT) and low molecular weight chitosan glucose biosensor (GOD-LMCHI/PT), respectively. The apparent Michaelis-Menten constant () was found to be 12.737 mM for GOD-MMCHI/PT and 17.692 mM for GOD-LMCHI/PT. This indicated that GOD-MMCHI/PT had greater affinity for the enzyme. Moreover, GOD-MMCHI/PT showed higher sensitivity (52.3666 nA/mM glucose) when compared with GOD-LMCHI/PT (9.8579 nA/mM glucose) at S/N>3. Better repeatability and reproducibility were achieved with GOD-MMCHI/PT than GOD-LMCHI/PT regarding glucose measurement. GOD-MMCHI/PT was found to give the highest enzymatic activity among the electrodes under investigation. The extent of interference encountered by GOD-MMCHI/PT and GOD-LMCHI/PT was not significantly different. Although the Nafion coated biosensor significantly reduced the signal due to the interferents under study, it also significantly reduced the response to glucose. The performance of the biosensors in the determination of glucose in rat serum was evaluated. Comparatively better accuracy and recovery results were obtained for GOD-MMCHI/PT. Hence, GOD-MMCHI/PT showed a better performance when compared with GOD-LMCHI/PT. In conclusion, chitosan membranes shave

  11. Comparative study of controlled pore glass, silica gel and poraver for the immobilization of urease to determine urea in a flow injection conductimetric biosensor system.

    PubMed

    Limbut, Warakorn; Thavarungkul, Panote; Kanatharana, Proespichaya; Asawatreratanakul, Punnee; Limsakul, Chusak; Wongkittisuksa, Booncharoen

    2004-03-15

    This study compared the responses of three enzyme reactors containing urease immobilized on three types of solid support, controlled pore glass (CPG), silica gel and Poraver. The evaluation of each enzyme reactor column was done in a flow injection conductimetric system. When urea in the sample solution passed though the enzyme reactor, urease catalysed the hydrolysis of urea into charged products. A lab-built conductivity meter was used to measure the increase in conductivity of the solution. The responses of the enzyme reactor column with urease immobilized on CPG and silica gel were similar and were much higher than that of Poraver. Both CPG and silica gel reactor columns gave the same limit of detection, 0.5 mM, and the response was still linear up to 150mM. The analysis time was 4-5 min per sample. The enzyme reactor column with urease immobilized on CPG gave a slightly better sensitivity, 4% higher than the reactor with silica gel. The life time of the immobilized urease on CPG and silica gel were more than 310h operation time (used intermittently over 7 months). Good agreement was obtained when urea concentrations of human serum samples determined by the flow injection conductimetric biosensor system was compared to the conventional methods (Fearon and Berthelot reactions). These were statistically shown using the regression line and Wilcoxon signed rank tests. The results showed that the reactor with urease immobilized on silica gel had the same efficiency as the reactor with urease immobilized on CPG.

  12. Formulation Study on Immobilization of Spent Ion Exchange Resins in Polymer Cements

    SciTech Connect

    Lili Xia; Meiqiong Lin; Bao Liangjin

    2006-07-01

    Applying normal design and correlative computer software, a new matrix material and an excellent waste formulation were developed. Based on the theory calculations and normal design in this paper, using polymer complex cement as immobilization matrix that mixed with simulating spent ion exchange resin a new waste formulation was carried out. The characterization of solidified waste had been done after 28 days curing. The results conformed to the treatment of the waste about the requests of the national standard [GB14569-93-1]. Leach index of the solidified waste was excellent. An optimized formulation was recommended. (authors)

  13. Design and performance study of a novel immobilized hollow fiber membrane bioreactor.

    PubMed

    Yang, Ping; Teo, Wah-Koon; Ting, Yen-Peng

    2006-01-01

    A dual-layer coaxial hollow fiber (DLHF) bioreactor for cell immobilization developed to overcome nutrients transport limitation is presented. Cells were contained in the annular space between two coaxial hollow fibers, and nutrients were supplied by a forced convective transport from the shell side through the annular space to the lumen side. With judicious selection of the membrane materials, a low operating transmembrane pressure of 50 kPa, and using E. coli as the model organism, a high cell density of 10(11) cells/mL annular space volume and a high cell viability of (up to 80%) were obtained.

  14. Sulfur immobilization and lithium storage on defective graphene: A first-principles study

    NASA Astrophysics Data System (ADS)

    Zhao, Wen; Chen, Pengcheng; Tang, Peizhe; Li, Yuanchang; Wu, Jian; Duan, Wenhui

    2014-01-01

    Motivated by the recent progresses and remaining technical challenges in Li-S battery, we employ defective graphene as a prototype cathode framework to illustrate how battery performance is influenced by the mesoporous carbon materials. We show that the immobilization of S unavoidably sacrifices its ability to further interact with Li, which leads to an enhanced cycle life but a decreased capacity. Based on our calculated results, we suggest a suitable S binding-energy range of ˜4-5 eV to balance the battery stability and capability under thermodynamic equilibrium conditions. Our results may promote the understanding and architecture design of Li-S battery.

  15. Sulfur immobilization and lithium storage on defective graphene: A first-principles study

    SciTech Connect

    Zhao, Wen; Chen, Pengcheng; Tang, Peizhe; Wu, Jian; Duan, Wenhui E-mail: dwh@phys.tsinghua.edu.cn; Li, Yuanchang E-mail: dwh@phys.tsinghua.edu.cn

    2014-01-27

    Motivated by the recent progresses and remaining technical challenges in Li-S battery, we employ defective graphene as a prototype cathode framework to illustrate how battery performance is influenced by the mesoporous carbon materials. We show that the immobilization of S unavoidably sacrifices its ability to further interact with Li, which leads to an enhanced cycle life but a decreased capacity. Based on our calculated results, we suggest a suitable S binding-energy range of ∼4–5 eV to balance the battery stability and capability under thermodynamic equilibrium conditions. Our results may promote the understanding and architecture design of Li-S battery.

  16. Kinetic Measurements for Enzyme Immobilization.

    PubMed

    Cooney, Michael J

    2017-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of this enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten were advancing their work by studying the kinetics of an enzyme saccharase which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis and ever since the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, and selectivity towards nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adapted to the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V max, K M) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  17. Kinetic measurements for enzyme immobilization.

    PubMed

    Cooney, Michael J

    2011-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of the enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten had advanced this work by studying the kinetics of the enzyme saccharase, which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis, and ever since, the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, selectivity toward nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adopted for the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V(max), K(M)) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review, enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  18. Immobilization of laccase for biotechnology applications.

    PubMed

    Sanlıer, Senay Hamarat; Gider, Simge; Köprülü, Alper

    2013-08-01

    Laccase played an important role in the decolorization of wide spectrum dyes as a low-cost and environmentally friendly technology. Laccase was immobilized in alginate beads and immobilization conditions were identified. 25 mg/ml laccase enzyme encapsulation efficiencies of using the prepared bead was calculated as approximately 94%. At the end of the 10 days of storage, the free laccase and immobilized laccase retained about 8.08% and 80.83%, respectively. The decolorization of the dye (Direct Blue 2) was around 86% for immobilized enzyme at 45°C. In the study, compared to the free enzyme, high activity, stable, reusable immobilized enzyme preparation was prepared.

  19. Comparative study of the nitrification characteristics of two different nitrifier immobilization methods.

    PubMed

    Li, Zhirong; Zhang, Zhi; Li, Jun; Zhang, Zhenjia

    2009-11-01

    The research investigated the nitrification characteristics of two different immobilization methods: nitrifier encapsulation in polyethylene glycol (PEG) gel pellets and nitrifier biofilm attachment on elastic plastic filler. The two carriers were placed in identical reactors. They reached a maximum nitrification rate of 39 and 25 mgN/L.h 30 days after start-up. The results showed that the nitrification efficiency in the PEG reactor was higher than in the biofilm reactor under the same conditions. Variations in temperature decreased the nitrification rate by approximately 55% in the PEG reactor from 28 to 8 degrees C, while 74.2% in the biofilm reactor. When the COD loading rate was increased to 0.8 kg/m(3) day, the nitrification efficiency in the biofilm reactor dropped sharply to 23%, and that of PEG reactor remained over 80%. PEG pellets with a high nitrification rate under all conditions showed promise as an immobilization medium, and are likely to be utilized in the nitrification of high-strength ammonia and COD wastewater during long-term operation.

  20. [An FTIR and XPS study of immobilization of chromium with fly ash based geopolymers].

    PubMed

    Liu, Si-Feng; Wang, Pei-Ming; Li, Zong-Jin; Lo, Irene M C

    2008-01-01

    Immobilization of Cr3+ with fly ash geopolymers was investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopic (XPS) techniques. The chromium sludge, as Cr(OH)3, was prepared with chemical precipitation method. The amounts of aluminum and silicon leached before and after the chromium sludge addition were measured using ICP-AES. The results suggested that the amounts of silicon and aluminum leached were reduced for the fly ash geopolymers after chromium sludge was incorporated. The decrease of silicon leaching was more pronounced than aluminum. FTIR results showed that the intensity of the main peak shifted into lower and the wave number of Si--O--Si and Al--O--Si became higher. The XPS results indicated that the O(1s) bind energy decreased, Si(2p) and Cr(2p) bind energy increased, while Al(2p) bind energy remained unchanged due to Cr3+ addition. It was also confirmed that the chromium is easily incorporated into the fly ash geopolymers paste, and polymerized with silicate units. The immobilization of Cr3+ using fly ash geopolymers is attributed not only to physical encapsulation, but also to chemical reaction.

  1. Kinetics and bioreactor studies of immobilized invertase on polyurethane rigid adhesive foam.

    PubMed

    Cadena, Pabyton G; Wiggers, Frank N; Silva, Roberto A; Lima Filho, José L; Pimentel, Maria C B

    2011-01-01

    A new support, polyurethane rigid adhesive foam (PRAF), which can be used to cover internal surface of metallic tubes, was used to immobilize invertase for application in an enzymatic bioreactor. The kinetic parameters were: Km--46.5±1.9 mM (PRAF-invertase) and 61.2±0.1 mM (free enzyme) and Vmax 42.0±4.3 U/mg protein/min (PRAF-invertase) and 445.3±24.0 U/mg protein/min (free invertase). The PRAF-invertase derivative maintained 50.1% of initial activity (69.17 U/g support) for 8 months (4°C) and was not observed microbial contamination. The bioreactor showed the best production of inverted sugar syrup using up-flow rate (0.48 L/h) with average conversion of 10.64±1.5% h(-1) at feeding rate (D) of 104 h(-1). The operational inactivation rate constant (kopi) and half-life were 1.92×10(-4) min(-1) and 60 h (continue use). The PRAF spray support looks promising as a new alternative to produce immobilized derivatives on reactor surfaces. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Extension type II pediatric supracondylar humerus fractures: a radiographic outcomes study of closed reduction and cast immobilization.

    PubMed

    Camus, Tristan; MacLellan, Brent; Cook, Peter Christopher; Leahey, John Lorne; Hyndman, John C; El-Hawary, Ron

    2011-06-01

    The treatment of Gartland type II pediatric supracondylar humerus fractures remains controversial. Some argue that closed reduction and cast immobilization is sufficient to treat these fractures, whereas others advocate closed reduction and percutaneous pinning. The purpose of this radiographic outcomes study was to determine whether closed reduction and cast immobilization could successfully obtain and maintain acceptable reduction of extension type II supracondylar humerus fractures. Prereduction, immediate postreduction, and final radiographs of 155 extension type II fractures that were treated nonoperatively were measured according to the parameters determined earlier to assess the position and alignment of the fracture fragments. These included the anterior humeral line, humerocapitellar angle, Baumann's angle, the Gordon index, and the Griffet index. The average age of the 155 patients at the time of injury was 5.3 years (range: 1 to 13 y). Analysis of the final radiographs, at the final follow-up of 5.3 months, showed that in 80% of patients, the anterior humeral line remained anterior to the mid-third segment of the capitellum (radiographic extension deformity), the mean humerocapitellar angle was 23.77 degrees (range: -11 to 50 degrees), the mean Baumann's angle was 79.40 degrees (range: 62 to 97 degrees), the mean Gordon index was 4.59%, and 44% of patients had a Griffet index between 1 and 3. From this radiographic review, it was observed that not all fractures treated with closed reduction and cast immobilization achieved anatomic position and alignment at final follow-up; however, the long-term clinical and radiographic significance of these findings remains unknown.

  3. “Click” Immobilization on Alkylated Silicon Substrates: Model for the Study of Surface Bound Antimicrobial Peptides

    PubMed Central

    Li, Yan; Santos, Catherine M.; Kumar, Amit; Zhao, Meirong; Lopez, Analette I.; Qin, Guoting; McDermott, Alison M.

    2011-01-01

    We describe an effective approach for the covalent immobilization of antimicrobial peptides (AMPs) to bioinert substrates via CuI-catalyzed azide–alkyne cycloaddition (CuAAC). The bioinert substrates were prepared by surface hydrosilylation of oligo-(ethylene glycol) (OEG) terminated alkenes on hydrogen-terminated silicon surfaces. To render the OEG monolayers “clickable”, mixed monolayers were prepared using OEG-alkenes with and without a terminal alkyne protected by a trimethylgermanyl (TMG) group. The mixed monolayers were characterized by X-ray photoelectron spectroscopy (XPS), elliposometry and contact angle measurement. The TMG protecting group can be readily removed to yield a free terminal alkyne by catalytic amounts of CuI in an aqueous media. This step can then be combined with the subsequent CuAAC reaction. Thus, the immobilization of an azide modified AMP (N3-IG-25) was achieved in a one-pot de-protection/coupling reaction. Varying the ratio of the two alkenes in the deposition mixture allowed for control over the density of the alkynyl groups in the mixed monolayer, and subsequently the coverage of the AMPs on the monolayer. These samples allowed for study of the dependence of antimicrobial activities on the AMP density. The results show that a relative low coverage of AMPs (~1.6×1013 molecule per cm2) is sufficient to significantly suppress the viability of Pseudomonas aeruginosa, while the surface presenting the highest density of AMPs (~2.8×1013 molecule per cm2) is still cyto-compatible. The remarkable antibacterial activity is attributed to the long and flexible linker and the site-specific “click” immobilization, which may facilitate the covalently attached peptides to interact with and disrupt the bacterial membranes. PMID:21264959

  4. Wastewater treatment by immobilized cells

    SciTech Connect

    Tyagi, R.D.; Vembu, K.

    1990-01-01

    Immobilized cell processes for wastewater treatment have only recently been intensively studied and applied. Essential information on the feasibility of various immobilization methods has been reviewed and examined with special reference to wastewater treatment. Included are the suitability of various supports, techniques used for microbial attachment factors affecting affinity for the support, strength of fixation, nature of polymers, role of radical groups, properties of attached microorganisms, effects of carriers on settling properties of biomass, characteristics of biofilm on carriers, and changes in cell metabolism as a result of immobilization. The morphologies for identification of immobilized cells, the methods of identification of structure and composition of microbial aggregates, and analytical methods for the estimate of biomass in the presence of carriers are discussed. Applications of immobilized cells to toxic wasted, anaerobic and aerobic systems, and operational criteria for different wastes are specified. The results of immobilized microalgae and cyanobacteria for wastewater treatment are reported and their future prospects are highlighted. Various immobilized cell bioreactor configurations have been critically reviewed with respect to design and granulation process including the topics of: biomass retention, resistance to washout, diffusional resistances, response to toxic shocks, theoretical aspects of hydrodynamic characteristics, start-up and steady-state processes, selection of support particles, particle size and active biomass, head loss considerations, surface area, reactor liquid velocity, hydraulic retention time aerobic versus anaerobic systems, temperature and substrate concentration effects, metabolic interspecies transfer, stability, suspended solids and microbial film interactions, solids residence time requirements, and operational issues.

  5. Si-F complexing in aqueous fluids: experimental study and implications for transport of immobile elements

    NASA Astrophysics Data System (ADS)

    Dolejš, David

    2014-05-01

    Intepretation of fluid-mineral interaction mechanisms and hydrothermal fluxes requires knowledge of predominant solubility and speciation reactions and their thermodynamic properties. Fluorine represents a hard electron donor, capable of complexing and transporting high-field strength elements, which are traditionally considered to be immobile. Reactions responsible for element mobility have general form MOx + y HF (aq) + x - y H2O = M(OH)2x-yFy (aq), and their extent and transport efficiency relies on hydrogen fluoride activity. In natural fluids, a[HF] is controlled by various fluorination equilibria including neutralization of silicates with consequent formation of silicohydroxyfluoride complexes. Quartz solubility in HF-H2O fluids was experimentally determined at 400-800 oC and 100-200 MPa using rapid-quench cold-seal pressure vessels and the mineral weight-loss method. Quartz solubility significantly increases in the presence of hydrogen fluoride: at 400 oC and 100 MPa, dissolved SiO2 ranges from 0.18 wt. % in pure H2O to 12.2 wt. % at 8.3 wt. % F in the fluid, whereas at 800 oC and 200 MPa it rises from 1.51 wt. % in pure H2O to 15.3 wt. % at 8.0 wt. % F in the fluid. The isobaric solubilities of quartz appear to be temperature-independent, i.e., effects of temperature vs. fluid density on the solubility are counteracting. The experimental data are described by the density model: log m[SiO2] = a + blog ρ + clog m[F] + dT , where a = -1.049 mol kg-1, b = 0.816 mol cm-3, c = 0.802 and d = 1.256 · 10-3 mol kg-1 K-1. Solubility isotherms have similar d(log m[SiO2])/d(log m[F]) slopes over the entire range of conditions indicating that Si(OH)2F2 is the major aqueous species. Several factors promote breakdown of silicohydroxyfluoride complexes and precipitation of silica solute: (i) decreasing temperature and pressure, i.e., fluid ascent and cooling and/or (ii) neutralization and increase in the alkali/H ratio of fluids during alteration reactions or removal of

  6. Preliminary studies of chemical immobilization of captive juvenile estuarine (Crocodylus porosus) and Australian freshwater (C. johnstoni) crocodiles with medetomidine and reversal with atipamezole.

    PubMed

    Olsson, Annabelle; Phalen, David

    2012-07-01

    To establish a safe, reliable and reversible immobilization protocol for captive juvenile crocodiles. Prospective, randomized, clinical study. Thirty male estuarine crocodiles (body mass 1-12.1 kg) and 10 male Australian freshwater crocodiles (body mass 4.1-12.8 kg). An optimized dose of medetomidine (0.5 mg kg(-1)) was administered intramuscularly (IM) into the tail (Group 1; n = 5), pelvic limb (Group 2; n = 5) and thoracic limb (Groups 3 and 4; n = 5 in each group) of estuarine crocodiles weighing 3-12.1 kg. Their heart and respiratory rates and degree of immobilization were monitored every 15 minutes until recovery and daily thereafter for 3 subsequent days. In Group 4 (n = 5), medetomidine was antagonized with an optimized dose of atipamezole (2.5 mg kg(-1)) given IM into the thoracic limb and time to recovery recorded. The effects of increasing doses of medetomidine given IM in the thoracic limb (n = 4) and intravenously (n = 6) were determined in 1-2 kg estuarine crocodiles. Australian freshwater crocodiles (4.1-12.8 kg) were administered medetomidine IM into the thoracic limb in divided doses at 0.5 mg kg(-1) (n = 5) and 0.75 mg kg(-1) (n = 5) and similarly monitored. Immobilization was achieved only in the estuarine crocodiles >3 kg and when medetomidine was administered into the thoracic limb. Immobilization was achieved within 30 minutes and the duration of immobilization lasted approximately 90 minutes. Immobilization in estuarine crocodiles was readily reversed with atipamezole. A dose of 0.75 g kg(-1) was required to immobilize Australian freshwater crocodiles and the onset of immobilization was longer and the duration shorter than seen in the estuarine crocodiles. The heart and respiratory rates of all immobilized animals decreased significantly and arterial blood pressure became undetectable in the animals in which it was measured. Medetomidine administered in the thoracic limb of captive estuarine and Australian freshwater crocodiles, ranging from

  7. Evaluation of antifertility effect of gel formulation containing sperm immobilizing factor: In vitro and in vivo studies.

    PubMed

    Gupta, Sonia; Kaur, Indu Pal; Prabha, Vijay

    2016-01-01

    Sexually active women often seek protection against unplanned pregnancies. Latter can be effectively controlled by consistent use of spermicides during each coital act. However, side effects associated with the use of available synthetic spermicidal agents have directed the interest towards identifying newer and safer agents. Present studies were undertaken to formulate a vaginal contraceptive gel, containing sperm immobilizing factor (SIF) isolated from Staphylococcus aureus using 1% w/v Carbopol. SIF loaded gel formulation was characterized for various in vitro parameters i.e. pH, spreadability, texture profiling, rheological properties, and in vitro release studies. The prepared formulation was found to possess significant spreading properties, gel firmness and strength, and released about 80% of SIF within 30min. Latter can completely immobilize human spermatozoa within 20s, at a dose of 200μg/ml. SIF in the proposed gel formulation showed 100% contraceptive effect when used at amount as low as of 10μg, thus confirming the possibility to develop it as a potent vaginal contraceptive for future use.

  8. Treatment of textile effluent in a developed phytoreactor with immobilized bacterial augmentation and subsequent toxicity studies on Etheostoma olmstedi fish.

    PubMed

    Watharkar, Anuprita D; Khandare, Rahul V; Waghmare, Pankajkumar R; Jagadale, Ashwini D; Govindwar, Sanjay P; Jadhav, Jyoti P

    2015-01-01

    A static hydroponic bioreactor using nursery grown plants of Pogonatherum crinitum along with immobilized Bacillus pumilus cells was developed for the treatment of textile wastewater. Independent reactors with plants and immobilized cells were also kept for performance and efficacy evaluation. The effluent samples characterized before and after their treatment showed that the plant-bacterial consortium reactor was more efficient than those of individual plant and bacterium reactors. COD, BOD, ADMI, conductivity, turbidity, TDS and TSS of the textile effluent was found to be reduced by 78, 70, 93, 4, 90, 13 and 70% respectively within 12 d by the consortial set. HPTLC analysis revealed the transformation of the textile effluent to new products. The phytotoxicity study on Phaeseolus mungo and Sorghum vulgare seeds showed reduced toxicity of treated effluents. The animal toxicity study performed on Etheostoma olmstedi fishes showed the toxic nature of untreated effluent giving extreme stress to fishes leading to death. Histology of fish gills exposed to treated effluent was found to be less affected. The oxidative stress related enzymes like superoxide dismutase and catalase were found to show decreased activities and less lipid peroxidation in fishes exposed to treated effluent.

  9. A density functional theory study of arsenic immobilization by the Al(III)-modified zeolite clinoptilolite.

    PubMed

    Awuah, Joel B; Dzade, Nelson Y; Tia, Richard; Adei, Evans; Kwakye-Awuah, Bright; Richard A Catlow, C; de Leeuw, Nora H

    2016-04-28

    We present density functional theory calculations of the adsorption of arsenic acid (AsO(OH)3) and arsenous acid (As(OH)3) on the Al(III)-modified natural zeolite clinoptilolite under anhydrous and hydrated conditions. From our calculated adsorption energies, we show that adsorption of both arsenic species is favorable (associative and exothermic) under anhydrous conditions. When the zeolite is hydrated, adsorption is less favourable, with the water molecules causing dissociation of the arsenic complexes, although exothermic adsorption is still observed for some sites. The strength of interaction of the arsenic complexes is shown to depend sensitively on the Si/Al ratio in the Al(III)-modified clinoptilolite, which decreases as the Si/Al ratio increases. The calculated large adsorption energies indicate the potential of Al(iii)-modified clinoptilolite for arsenic immobilization.

  10. Study of concentration of HPV DNA probe immobilization for cervical cancer detection based IDE biosensor

    NASA Astrophysics Data System (ADS)

    Roshila, M. L.; Hashim, U.; Azizah, N.

    2016-07-01

    This paper mainly illustrates regarding the detection process of Human Papillomavirus (HPV) DNA probe. HPV is the most common virus that infected to human by a sexually transmitted virus. The most common high-risk HPV are 16 and 18. Interdigitated electrode (IDE) device used as based of Titanium Dioxide (TiO2) acts as inorganic surface, where by using APTES as a linker between inorganic surface and organic surface. A strategy of rapid and sensitive for the HPV detection was proposed by integrating simple DNA extraction with a gene of DNA. The extraction of the gene of DNA will make an efficiency of the detection process. It will depend on the sequence of the capture probes and the way to support their attached. The fabrication, surface modification, immobilization and hybridization processes are characterized by current voltage (I-V) measurement by using KEITHLEY 6487. This strategy will perform a good sensitivity of HPV detection.

  11. Laccase Spontaneous Adsorption Immobilization: Experimental Studies and Mathematical Modeling at Enzymatic Fuel Cell Cathode Construction

    NASA Astrophysics Data System (ADS)

    Arkadeva, I. N.; Bogdanovskaya, V. A.; Vasilenko, V. A.; Fokina, E. A.; Koltsova, E. M.

    2017-08-01

    The activity of a bioeletrode is largely determined by the amount of enzyme adsorbed on its active layer, including the distribution of enzyme along thickness in the carrier layer. The distribution of enzyme is also required for calculations of the characteristics of bioelectrocatalysis process using a mathematical model. In the present article, on the basis of conducted experimental research a mathematical model of laccase immobilization by spontaneous adsorption on carbon-based sorbentsof different nature was developed. The model can be used to predict adsorption value and enzyme distribution in the layer of an adsorbent. The model includes the equations of the enzyme concentration changing due to its adsorption on the surface of the carbon material (CM) and the enzyme diffusion over the thickness of CM. The diffusion equation is based on the second Fick’s law and contains fractional derivatives instead of the first oder derivative.

  12. Method for immobilizing microbial cells on gel surface for dynamic AFM studies.

    PubMed Central

    Gad, M; Ikai, A

    1995-01-01

    The processes of cell growth and budding of the yeast cells Saccharomyces cerevisiae, which were gently immobilized on 3% agar and submerged in culture medium, were successfully imaged with an atomic force microscope for 6-7 h. Similar experiments on chemically fixed cells did not detect any appreciable change in their appearance except in a few scannings at the very beginning, indicating that the dissolution of agar and/or scraping of its surface by the scanning tip, if any, did not significantly interfere with the images taken thereafter. The increment in the height of many of the untreated cells, accompanied by their lateral enlargement, was taken as an indication of successful imaging of the growth process of yeast cells, together with an image of a growing daughter cell attached to its mother cell. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 5 FIGURE 7 FIGURE 8 PMID:8599630

  13. Quantitative affinity chromatographic studies of mitochondrial cytochrome c binding to bacterial photosynthetic reaction center, reconstituted in liposome membranes and immobilized by detergent dialysis and avidin--biotin binding.

    PubMed

    Yang, Q; Liu, X Y; Hara, M; Lundahl, P; Miyake, J

    2000-04-10

    In order to study the affinity binding of c-type cytochromes to the photosynthetic reaction center (RC) by quantitative affinity chromatography (QAC), RC from Rhodobacter sphaeroides was reconstituted into liposomes composed of egg phosphatidylcholine (EPC) and 2 mol% of biotinyl phosphatidylethanolamine simultaneously as the liposomes were formed and immobilized in (strept)avidin-coupled gel beads by rotary detergent dialysis. The immobilized amount was up to 80 nmol of RC and 33 micromol of lipid/g of moist gel in streptavidin-coupled Sephacryl S-1000 gel. By QAC frontal runs, retardation of mitochondrial cyt c on immobilized RC liposome columns was demonstrated. The dissociation constant for the RC-cyt c interaction was determined to be 0.20-0.57 microM. QAC studies also allowed evaluation of the orientation of reconstituted RC in immobilized liposomes by comparison of the total amount of cyt c binding sites with the amount of available binding sites obtained by QAC. It seems that the RC proteoliposomes immobilized in Sephacryl S-1000 gel exposed the cyt c binding sites on the outer surface of the liposomes due to effects of the gel network pore size and the resulting liposomal size.

  14. Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

    NASA Astrophysics Data System (ADS)

    ElKaoutit, Mohammed; Naranjo-Rodriguez, Ignacio; Domínguez, Manuel; Hidalgo-Hidalgo-de-Cisneros, José Luis

    2011-10-01

    Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its "native" state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

  15. Chemically immobilized and physically adsorbed PAN/acetylacetone modified mesoporous silica for the recovery of rare earth elements from the waste water-comparative and optimization study.

    PubMed

    Ramasamy, Deepika Lakshmi; Repo, Eveliina; Srivastava, Varsha; Sillanpää, Mika

    2017-05-01

    This study was aimed at the investigation of Rare Earth Element (REE) recovery from aqueous solution by silica gels with 1-(2-Pyridylazo) 2-naphthol (PAN) and acetyl acetone (Acac) modifications. The two different methods of silica gel chelation, such as chemical immobilization with the help of silane coupling agents (3-aminopropyl triethoxysilane (APTES) and 3-aminopropyl trimethoxysilane (APTMS) in this study) and direct physical adsorption onto the silica surface, is compared in terms of their REE removal efficiency. A comparative analysis between adsorption of different REEs for different silica gels is performed and the influence of parameters such as pH, contact time, temperature and initial concentration has been reported. The effect of calcined adsorbents on the adsorption process is also investigated. Characterization studies on silica gels by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD) and zeta potential analysis are performed to better understand the relation between physical/chemical attributes of the adsorbents and their impact on the adsorption process. The experimental results are evaluated and optimal conditions for REE adsorption are identified. Chemically immobilized gels demonstrated immense potential for all the REE under study except Sc, for which, physically loaded gels seemed to be more efficient. The removal of REEs could be achieved at lower pHs by chemically immobilized PAN/Acac gels, making it suitable for many practical applications. The amine functionalized gels before chemical immobilization step were compared with PAN/Acac chemically immobilized gels in single as well as multi element system and the significance of chemical immobilization after amine functionalization is also stated.

  16. A DFT+U study of Pu immobilization in Gd2Zr2O7

    NASA Astrophysics Data System (ADS)

    Zhao, F. A.; Xiao, H. Y.; Jiang, M.; Liu, Z. J.; Zu, X. T.

    2015-12-01

    The solubility of Pu in Gd2Zr2O7 has been investigated by the density functional theory plus Hubbard U correction. It is found that the formation of PuGdZr2O7, Gd2PuZrO7 and Gd2Pu1.5Zr0.5O7 are exothermic, whereas Pu0.5Gd1.5Zr2O7, Pu1.5Gd0.5Zr2O7 and Gd2Pu0.5Zr1.5O7 are energetically less stable than their respective separated states. The calculations show that both the Gd and Zr lattice sites can be substituted by the Pu, which is consistent with the immobilization behavior of uranium in Gd2Zr2O7 observed experimentally. The site preference of Pu in Gd2Zr2O7 is found to be dependent on the chemical environment, i.e., Pu prefers to substitute for Gd-site under Gd-rich and O2-rich conditions and for Zr-site under Zr-rich and O2-rich conditions.

  17. Protein immobilization techniques for microfluidic assays

    PubMed Central

    Kim, Dohyun; Herr, Amy E.

    2013-01-01

    Microfluidic systems have shown unequivocal performance improvements over conventional bench-top assays across a range of performance metrics. For example, specific advances have been made in reagent consumption, throughput, integration of multiple assay steps, assay automation, and multiplexing capability. For heterogeneous systems, controlled immobilization of reactants is essential for reliable, sensitive detection of analytes. In most cases, protein immobilization densities are maximized, while native activity and conformation are maintained. Immobilization methods and chemistries vary significantly depending on immobilization surface, protein properties, and specific assay goals. In this review, we present trade-offs considerations for common immobilization surface materials. We overview immobilization methods and chemistries, and discuss studies exemplar of key approaches—here with a specific emphasis on immunoassays and enzymatic reactors. Recent “smart immobilization” methods including the use of light, electrochemical, thermal, and chemical stimuli to attach and detach proteins on demand with precise spatial control are highlighted. Spatially encoded protein immobilization using DNA hybridization for multiplexed assays and reversible protein immobilization surfaces for repeatable assay are introduced as immobilization methods. We also describe multifunctional surface coatings that can perform tasks that were, until recently, relegated to multiple functional coatings. We consider the microfluidics literature from 1997 to present and close with a perspective on future approaches to protein immobilization. PMID:24003344

  18. Joint Immobilization of Plant Growth-Promoting Bacteria and Green Microalgae in Alginate Beads as an Experimental Model for Studying Plant-Bacterium Interactions▿

    PubMed Central

    de-Bashan, Luz E.; Bashan, Yoav

    2008-01-01

    A simple, quantitative experimental model, offering a convenient and basic approach to studies of plant-bacterium interactions, is proposed. This involves immobilizing a unicellular, freshwater microalga, a Chlorella species, serving as the plant, with a plant growth-promoting bacterium, an Azospirillum species, in small alginate beads to allow close interaction and to avoid external interference from bacterial contaminants. PMID:18791009

  19. Application of lipase immobilized on the biocompatible ternary blend polymer matrix for synthesis of citronellyl acetate in non-aqueous media: kinetic modelling study.

    PubMed

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2014-04-10

    This work reports the use of new support for immobilization of lipase Burkholderia cepacia (BCL) matrix made up of polylactic acid (PLA), chitosan (CH), and polyvinyl alcohol (PVA). Initially lipase from various microbial sources and immobilization support composition was screened to obtain a robust biocatalyst. Among various biocatalysts preparation, the PLA:PVA:CH:BCL (1:6:1:2) was worked as a robust biocatalyst for the citronellyl acetate synthesis. Various reaction parameters were studied in detail to obtain the suitable reaction conditions for model citronellyl acetate synthesis reaction. Various kinetic parameters such as r(max), K(i(citronellol)), K(m(citronellol)), K(m(vinyl acetate)) were determined using non-linear regression analysis for the ternary complex as well as bi-bi ping-pong mechanism. The experimental results and kinetic study showed that citronellyl acetate synthesis catalyzed by immobilized lipase BCL followed the ternary complex mechanism with inhibition by alcohol (citronellol). The energy of activation for citronellyl acetate synthesis was found to be lower for immobilized lipase (8.9 kcal/mol) than aggregated lipase (14.8 kcal/mol) enzyme. The developed biocatalyst showed four to fivefold higher catalytic activity and excellent recyclability (up to six cycles) than the aggregated lipase. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Effect of computerized cognitive training with virtual spatial navigation task during bed rest immobilization and recovery on vascular function: A pilot study

    PubMed Central

    Goswami, Nandu; Kavcic, Voyko; Marusic, Uros; Simunic, Bostjan; Rössler, Andreas; Hinghofer-Szalkay, Helmut; Pisot, Rado

    2015-01-01

    We investigated the effects of bed rest (BR) immobilization, with and without computerized cognitive training with virtual spatial navigation task (CCT), on vascular endothelium on older subjects. The effects of 14-day BR immobilization in healthy older males (n=16) of ages 53–65 years on endothelial function were studied using EndoPAT®, a noninvasive and user-independent method. From the group of 16 older men, 8 randomly received CCT during the BR, using virtual navigation tasks in a virtual environment with joystick device. In all the cases, EndoPAT assessments were done at pre- and post-BR immobilization as well as following 28 days of ambulatory recovery. The EndoPAT index increased from 1.53±0.09 (mean ± standard error of the mean) at baseline to 1.61±0.16 following immobilization (P=0.62) in the group with CCT. The EndoPAT index decreased from 2.06±0.13 (mean ± standard error of the mean) at baseline to 1.70±0.09 at the last day of BR study, day 14 (BR14) (P=0.09) in the control group. Additionally, there were no statistically significant differences between BR14 and at 28 days of follow-up (rehabilitation program) (R28). Our results show a trend of immobilization in older persons affecting the vasoconstrictory endothelial response. As the control subjects had a greater increase in EndoPAT index after R28 (+0.018) compared to subjects who had cognitive training (+0.11) (calculated from the first day of BR study), it is possible that cognitive training during BR does not improve endothelial function but rather contributes to slowing down the impairment of endothelial function. Finally, our results also show that EndoPAT may be a useful noninvasive tool to assess the vascular reactivity. PMID:25709419

  1. Carbon nanotubes as supports for inulinase immobilization.

    PubMed

    Garlet, Tais B; Weber, Caroline T; Klaic, Rodrigo; Foletto, Edson L; Jahn, Sergio L; Mazutti, Marcio A; Kuhn, Raquel C

    2014-09-15

    The commercial inulinase obtained from Aspergillus niger was non-covalently immobilized on multiwalled carbon nanotubes (MWNT-COOH). The immobilization conditions for the carbon nanotubes were defined by the central composite rotational design (CCRD). The effects of enzyme concentration (0.8%-1.7% v/v) and adsorbent:adsorbate ratio (1:460-1:175) on the enzyme immobilization were studied. The adsorbent:adsorbate ratio variable has positive effect and the enzyme concentration has a negative effect on the inulinase immobilization (U/g) response at the 90% significance level. These results show that the lower the enzyme concentration and the higher the adsorbent:adsorbate ratio, better is the immobilization. According to the results, it is possible to observe that the carbon nanotubes present an effective inulinase adsorption. Fast adsorption in about six minutes and a loading capacity of 51,047 U/g support using a 1.3% (v/v) inulinase concentration and a 1:460 adsorbent:adsorbate ratio was observed. The effects of temperature on the immobilized enzyme activity were evaluated, showing better activity at 50 °C. The immobilized enzyme maintained 100% of its activity during five weeks at room temperature. The immobilization strategy with MWNT-COOH was defined by the experimental design, showing that inulinase immobilization is a promising biotechnological application of carbon nanotubes.

  2. Production of L-glutamic Acid with Corynebacterium glutamicum (NCIM 2168) and Pseudomonas reptilivora (NCIM 2598): A Study on Immobilization and Reusability.

    PubMed

    Shyamkumar, Rajaram; Moorthy, Innasi Muthu Ganesh; Ponmurugan, Karuppiah; Baskar, Rajoo

    2014-07-01

    L-glutamic acid is one of the major amino acids that is present in a wide variety of foods. It is mainly used as a food additive and flavor enhancer in the form of sodium salt. Corynebacterium glutamicum (C. glutamicum) is one of the major organisms widely used for glutamic acid production. The study was dealing with immobilization of C. glutamicum and mixed culture of C. glutamicum and Pseudomonas reptilivora (P. reptilivora) for L-glutamic acid production using submerged fermentation. 2, 3 and 5% sodium alginate concentrations were used for production and reusability of immobilized cells for 5 more trials. The results revealed that 2% sodium alginate concentration produced the highest yield (13.026±0.247 g/l by C. glutamicum and 16.026±0.475 g/l by mixed immobilized culture). Moreover, reusability of immobilized cells was evaluated in 2% concentration with 5 more trials. However, when the number of cycles increased, the production of L-glutamic acid decreased. Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition. It also minimizes external contamination. Glutamic acid production gradually decreased due to multiple uses of beads and consequently it reduces the shelf life.

  3. Energy transfer between surface-immobilized light-harvesting chlorophyll a/b complex (LHCII) studied by surface plasmon field-enhanced fluorescence spectroscopy (SPFS).

    PubMed

    Lauterbach, Rolf; Liu, Jing; Knoll, Wolfgang; Paulsen, Harald

    2010-11-16

    The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCII potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCII to be immobilized on a solid surface. In a previous study we showed the immobilization of recombinant LHCII on functionalized gold surfaces via a 6-histidine tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Förster energy transfer between immobilized LHCII on a functionalized surface have been analyzed by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCII.

  4. Production of L-glutamic Acid with Corynebacterium glutamicum (NCIM 2168) and Pseudomonas reptilivora (NCIM 2598): A Study on Immobilization and Reusability

    PubMed Central

    Shyamkumar, Rajaram; Moorthy, Innasi Muthu Ganesh; Ponmurugan, Karuppiah; Baskar, Rajoo

    2014-01-01

    Background L-glutamic acid is one of the major amino acids that is present in a wide variety of foods. It is mainly used as a food additive and flavor enhancer in the form of sodium salt. Corynebacterium glutamicum (C. glutamicum) is one of the major organisms widely used for glutamic acid production. Methods The study was dealing with immobilization of C. glutamicum and mixed culture of C. glutamicum and Pseudomonas reptilivora (P. reptilivora) for L-glutamic acid production using submerged fermentation. 2, 3 and 5% sodium alginate concentrations were used for production and reusability of immobilized cells for 5 more trials. Results The results revealed that 2% sodium alginate concentration produced the highest yield (13.026±0.247 g/l by C. glutamicum and 16.026±0.475 g/l by mixed immobilized culture). Moreover, reusability of immobilized cells was evaluated in 2% concentration with 5 more trials. However, when the number of cycles increased, the production of L-glutamic acid decreased. Conclusion Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition. It also minimizes external contamination. Glutamic acid production gradually decreased due to multiple uses of beads and consequently it reduces the shelf life. PMID:25215180

  5. Immobilization of Spirulina subsalsa for removal of triphenyltin from water.

    PubMed

    Huang, Guo-Lan; Zhihui, Song

    2002-07-01

    Spirulina subsalsa is immobilized with alginate, which increases the growth rate, chlorophyll content, phycocyanin content and nitrate reductase activity. Immobilized Spirulina subsalsa with alginate increases absorption of triphenyltin chloride (TPT). The phycocyanin of immobilized Spirulina subsalsa is more sensitive to TPT then free alga. The immobilization enhances the toxic effect of TPT on nitrate reductase activity of Spirulina subsalsa. Experimental results demonstrate that the immobilization of Spirulina subsalsa is feasible. Removal of TPT by immobilized Spirulina subsalsa reaches 68%. Biosorption mechanism of TPT by Spirulina subsalsa should be further studied.

  6. Pilot Study to Evaluate Hydrogen Injection for Stimulating Reduction and Immobilization of Uranium in Groundwater at an ISR Mining Site

    NASA Astrophysics Data System (ADS)

    Clapp, L. W.; Cabezas, J.; Gamboa, Y.; Fernandez, W.

    2011-12-01

    State and federal regulations require that groundwater at in-situ recovery (ISR) uranium mining operations be restored to pre-mining conditions. Reverse osmosis (RO) filtration of several pore volumes of the post-leached groundwater and reinjection of the clean permeate is the most common technology currently used for restoring groundwater at uranium ISR sites. However, this approach does not revert the formation back to its initial reducing conditions, which can potentially impede timely groundwater restoration. In-situ biostimulation of indigenous iron- and sulfate reducing bacteria by injection of organic electron donors (e.g., ethanol, acetate, and lactate) to promote soluble uranium reduction and immobilization has been the subject of previous studies. However, injection of organic substrates has been observed to cause aquifer clogging near the injection point. In addition, U(VI) solubility may be enhanced through complexation with carbonate generated by organic carbon oxidation. An alternative approach that may overcome these problems involves the use of hydrogen as a reductant to promote microbial reduction and immobilization of U(VI) in situ. To test this approach, approximately 100,000 scf of compressed hydrogen gas was injected into a leached unconsolidated sand zone over two months at an ISR mining site. During this time groundwater was recirculated between injection and extraction wells (separated by 130 ft) at a rate of about 40 gpm and bromide was coinjected as a conservative tracer. A well monitoring program has been executed since June 2009 to evaluate the performance of the hydrogen injection. Current results show that U(VI) has been reduced from 4.2 to 0.05 ppm in the area surrounding the injection well and to 2.0 ± 0.3 ppm in the area surrounding the extraction well and two intermediate monitoring wells. Other water quality changes near the injection well include significant decreases in concentrations of Mo, sulfate, Fe, Mn, bicarbonate, Ca

  7. Study on the effect of sulphur, glucose, nitrogen and plant residues on the immobilization of sulphate-S in soil.

    PubMed

    Shahsavani, S

    2009-02-15

    In order to evaluate the relationship between sulphur (S), glucose (G), nitrogen (N) and plant residues (st), on sulphur immobilization and microbial transformation. Five soil samples from 0-30 cm of Bastam farmer's fields of Shahrood area were collected. Eleven treatments with different levels of S, G, N and plant residues (wheat straw) were applied in a randomized block design with three replications and incubated over 20, 45 and 60 days. The immobilization of SO4(-2)-S presented as a percentage of that added, was inversely related to its addition rate. Additions of glucose and plant residues increased with the C-to-S ratio of the added amendments, irrespective of their origins (glucose and plant residues). In the presence of C sources (glucose or plant residues). N significantly increased the immobilization of SO4(-2)-S, whilst the effect of N was insignificant in the absence of a C amendment. In first few days the amounts of added SO4(-2)-S immobilized were linearly correlated with the amounts of added S recovered in the soil microbial biomass. With further incubation the proportions of immobilized SO4(-2)-S remaining as biomass-S decreased. Decrease in biomass-S was thought to be due to the conversion ofbiomass-S into soil organic-S. Glucose addition increased the immobilization (microbial utilization and incorporation into the soil organic matter) of native soil SO4(-2)-S. However, N addition enhance the mineralization of soil organic-S, increasing the concentration of SO4(-2)-S in soil and the extent to which available-S can be immobilized is determined by both the amount of available-S and the availability of an utilizable C source.

  8. Effects of 1 week of unilateral ankle immobilization on plantar-flexor strength, balance, and walking speed: a pilot study in asymptomatic volunteers.

    PubMed

    Caplan, Nick; Forbes, Andrew; Radha, Sarkhell; Stewart, Su; Ewen, Alistair; St Clair Gibson, Alan; Kader, Deiary

    2015-05-01

    Ankle immobilization is often used after ankle injury. To determine the influence of 1 week's unilateral ankle immobilization on plantar-flexor strength, balance, and walking gait in asymptomatic volunteers. Repeated-measures laboratory study. University laboratory. 6 physically active male participants with no recent history of lower-limb injury. Participants completed a 1-wk period of ankle immobilization achieved through wearing a below-knee ankle cast. Before the cast was applied, as well as immediately, 24 h, and 48 h after cast removal, their plantar-flexor strength was assessed isokinetically, and they completed a single-leg balance task as a measure of proprioceptive function. An analysis of their walking gait was also completed Main Outcome Measures: Peak plantar-flexor torque and balance were used to determine any effect on muscle strength and proprioception after cast removal. Ranges of motion (3D) of the ankle, knee, and hip, as well as walking speed, were used to assess any influence on walking gait. After cast removal, plantar-flexor strength was reduced for the majority of participants (P = .063, CI = -33.98 to 1.31) and balance performance was reduced in the immobilized limb (P < .05, CI = 0.84-5.16). Both strength and balance were not significantly different from baseline levels by 48 h. Walking speed was not significantly different immediately after cast removal but increased progressively above baseline walking speed over the following 48 h. Joint ranges of motion were not significantly different at any time point. The reduction in strength and balance after such a short period of immobilization suggested compromised central and peripheral neural mechanisms. This suggestion appeared consistent with the delayed increase in walking speed that could occur as a result of the excitability of the neural pathways increasing toward baseline levels.

  9. Exfoliated Egyptian kaolin immobilized heteropolyoxotungstate nanocomposite as an innovative antischistosomal agent: In vivo and in vitro bioactive studies.

    PubMed

    Bayaumy, Fatma E A; Darwish, Atef S

    2016-02-01

    This study aims to manipulate an antischistosomal nanocomposite based on exfoliated clay immobilized heteropolyoxotungstate. The nanocomposite's physicochemical characteristics were examined using XRD, Raman spectroscopy, FTIR, DLS, SEM, HR-TEM and AFM. Nano-sized spheroidal negatively charged Keggin-type heteropolyoxotungstate particles were developed along and between the exfoliated clay layers. The impact of the nanocomposite on Schistosoma mansoni-infected mice was studied through parasitological, physiological and histological analyses. Infected mice were orally vaccinated by a single nanocomposite dose (15mg/kg/day) for two weeks. The schistosomicidal activities of the nanocomposite in vitro were investigated by examining its dose- and time-dependent responses in terms of % worm mortality. The time-dependent morphological alterations in schistosomes at a nanocomposite dosage of 15μg/mL were followed by SEM. The nanocomposite exhibited potential schistosomicidal properties with a marked reduction in worm burden (~85% mortality), extensive deformities in the adult worm tegument and suckers, improvement of serum biochemical activities, and diminishment in granulomatous lesions. The in vitro release of heteropolyoxotungstate from exfoliated clay indicates the clay's ability to embrace the heteropolytungstate until its liberation at the parasitic districts. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A pilot feasibility study of daily rTMS to modify corticospinal excitability during lower limb immobilization

    PubMed Central

    Ricci, Raffaella; Ramsey, Dave; Johnson, Kevin; Borckardt, Jeffrey J; Vallejo, Matthew; Roberts, Donna R; George, Mark S

    2008-01-01

    Short term immobilization of the lower limb is associated with increased corticospinal excitability at 24 hours post cast removal. We wondered whether daily stimulation of the motor cortex might decrease brain reorganization during casting. We tested the feasibility of this approach. Using transcranial magnetic stimulation (TMS), resting motor threshold and recruitment curves were obtained at baseline in 6 healthy participants who then had leg casts placed for 10 days. On 7 of the 10 days subjects received 20 minutes of 1 Hz repetitive TMS (rTMS). TMS measures were then recorded immediately after and 24 hours post cast removal. Four of 6 subjects completed the study. At the group level there were no changes in excitability following cast removal. At the individual level, two participants did not show any change, 1 participant had higher and one lower excitability 24 hours after cast removal. Daily rTMS over motor cortex is feasible during casting and may modify neuroplastic changes occurring during limb disuse. A prospective double blind study is warranted to test whether daily rTMS might improve outcome in subjects undergoing casting, and perhaps in other forms of limb disuse such as those following brain injury or weightlessness in space flight. PMID:19209293

  11. A pilot feasibility study of daily rTMS to modify corticospinal excitability during lower limb immobilization.

    PubMed

    Ricci, Raffaella; Ramsey, Dave; Johnson, Kevin; Borckardt, Jeffrey J; Vallejo, Matthew; Roberts, Donna R; George, Mark S

    2008-10-01

    Short term immobilization of the lower limb is associated with increased corticospinal excitability at 24 hours post cast removal. We wondered whether daily stimulation of the motor cortex might decrease brain reorganization during casting. We tested the feasibility of this approach. Using transcranial magnetic stimulation (TMS), resting motor threshold and recruitment curves were obtained at baseline in 6 healthy participants who then had leg casts placed for 10 days. On 7 of the 10 days subjects received 20 minutes of 1 Hz repetitive TMS (rTMS). TMS measures were then recorded immediately after and 24 hours post cast removal. Four of 6 subjects completed the study. At the group level there were no changes in excitability following cast removal. At the individual level, two participants did not show any change, 1 participant had higher and one lower excitability 24 hours after cast removal. Daily rTMS over motor cortex is feasible during casting and may modify neuroplastic changes occurring during limb disuse. A prospective double blind study is warranted to test whether daily rTMS might improve outcome in subjects undergoing casting, and perhaps in other forms of limb disuse such as those following brain injury or weightlessness in space flight.

  12. Immobilization of bovine catalase onto magnetic nanoparticles.

    PubMed

    Doğaç, Yasemin İspirli; Teke, Mustafa

    2013-01-01

    The scope of this study is to achieve carrier-bound immobilization of catalase onto magnetic particles (Fe₃O₄ and Fe₂O₃NiO₂ · H₂O) to specify the optimum conditions of immobilization. Removal of H2O2 and the properties of immobilized sets were also investigated. To that end, adsorption and then cross-linking methods onto magnetic particles were performed. The optimum immobilization conditions were found for catalase: immobilization time (15 min for Fe₃O₄; 10 min for Fe2O₃NiO₂ · H₂O), the initial enzyme concentration (1 mg/mL), amount of magnetic particles (25 mg), and glutaraldehyde concentration (3%). The activity reaction conditions (optimum temperature, optimum pH, pH stability, thermal stability, operational stability, and reusability) were characterized. Also kinetic parameters were calculated by Lineweaver-Burk plots. The optimum pH values were found to be 7.0, 7.0, and 8.0 for free enzyme, Fe₃O₄-immobilized catalases, and Fe₂O₃NiO₂ · H₂O-immobilized catalases, respectively. All immobilized catalase systems displayed the optimum temperature between 25 and 35°C. Reusability studies showed that Fe₃O₄-immobilized catalase can be used 11 times with 50% loss in original activity, while Fe2O₃NiO₂ · H₂O-immobilized catalase lost 67% of activity after the same number of uses. Furthermore, immobilized catalase systems exhibited improved thermal and pH stability. The results transparently indicate that it is possible to have binding between enzyme and magnetic nanoparticles.

  13. Protein selectivity with immobilized metal ion-tacn sorbents: chromatographic studies with human serum proteins and several other globular proteins.

    PubMed

    Jiang, W; Graham, B; Spiccia, L; Hearn, M T

    1998-01-01

    The chromatographic selectivity of the immobilized chelate system, 1,4,7-triazocyclononane (tacn), complexed with the borderline metal ions Cu2+, Cr3+, Mn2+, Co2+, Zn2+, and Ni2+ has been investigated with hen egg white lysozyme, horse heart cytochrome c, and horse skeletal muscle myoglobin, as well as proteins present in partially fractionated preparations of human plasma. The effects of ionic strength and pH of the loading and elution buffers on protein selectivities of these new immobilized metal ion affinity chromatographic (IMAC) systems have been examined. The results confirm that immobilized Mn;pl-tacn sorbents exhibit a novel type of IMAC behavior with proteins. In particular, the chromatographic properties of these immobilized M(n+)-tacn ligand systems were significantly different compared to the IMAC behavior observed with other types of immobilized tri- and tetradentate chelating ligands, such as iminodiacetic acid, O-phosphoserine, or nitrilotriacetic acid, when complexed with borderline metal ions. The experimental results have consequently been evaluated in terms of the additional contributions to the interactive processes mediated by effects other than solely the conventional lone pair Lewis soft acid-Lewis soft base coordination interactions, typically found for the IMAC of proteins with borderline and soft metal ions, such as Cu2+ or Ni2+.

  14. Immobilization of cholesterol oxidase on cellulose acetate membrane for free cholesterol biosensor development.

    PubMed

    Wang, Shenqi; Li, Shipu; Yu, Yaoting

    2004-01-01

    This article describes the immobilization of cholesterol oxidase on a cellulose acetate (CA) membrane activated by Sodium periodate, ethylenediamine, and glutaraldehyde etc. The properties of the immobilized enzyme membrane were investigated. The factors affecting the activity of immobilized enzyme such as the concentration of glutaraldehyde, the concentration of enzyme used during immobilization, temperature, pH, and immobilizing time etc. were also studied. The immobilized COD membrane has been used to construct fibre-optic fluorescent biosensor.

  15. Screening of lipase inhibitors from Scutellaria baicalensis extract using lipase immobilized on magnetic nanoparticles and study on the inhibitory mechanism.

    PubMed

    Wan, Li-Hong; Jiang, Xiao-Lan; Liu, Yi-Ming; Hu, Jin-Jie; Liang, Jian; Liao, Xun

    2016-03-01

    Scutellaria baicalensis is a traditional Chinese medicinal plant possessing a wide variety of biological activities. In this work, lipase immobilized on magnetic nanoparticles (LMNPs) was used as solid phase extract absorbent for screening of lipase inhibitors from this plant. Three flavonoids were found to bind to LMNPs and were identified as baicalin, wogonin, and oroxylin A by liquid chromatography-mass spectrometry (HPLC-MS). Their IC50 values were determined to be 229.22 ± 12.67, 153.71 ± 9.21, and 56.07 ± 4.90 μM, respectively. Fluorescence spectroscopy and molecular docking were used to probe the interactions between these flavonoids and lipase. All the flavonoids quenched the fluorescence of lipase statically by forming new complexes, implying their affinities with the enzyme. The thermodynamic analysis suggested that van der Waals force and hydrogen bond were the main forces between wogonin and lipase, while hydrophobic force was the main force for the other two flavonoids. The results from a molecular docking study further revealed that all of them could insert into the pocket of lipase binding to a couple of amino acid residues.

  16. Microstructural and potential dependence studies of urease-immobilized gold nanoparticles-polypyrrole composite film for urea detection.

    PubMed

    Rajesh; Puri, Nidhi; Mishra, Sujeet K; Laskar, Mariam J; Srivastava, Avanish K

    2014-01-01

    Gold nanoparticle-polypyrrole nanocomposite film was electrochemically deposited in a single-step polymerization of pyrrole in the presence of 3-mercaptopropionic acid (MPA)-capped gold nanoparticles (GNPs) and p-toluenesulfonic acid (pTSA) on the surface of an indium tin oxide (ITO)-coated glass plate. The carboxyl functional groups surrounding the GNPs within the polymer matrix were utilized for the immobilization of urease enzyme through carbodiimide coupling reaction for the construction of a Urs/GNP(MPA)-PPy/ITO-glass bioelectrode for urea detection in Tris-HCl buffer. The resulting bioelectrode film was characterized by atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The potentiometric response of the bioelectrode made of polymer nanocomposite films of two different thicknesses prepared at 100 and 250 mC cm(-2) charge densities, respectively, was studied towards the urea concentration in Tris-HCl buffer (pH 7.4). The thin polymer nanocomposite film-based bioelectrode prepared at 100 mC cm(-2) charge density exhibited a comparatively good potentiometric response than a thick 250 mC cm(-2) charge density film with a linear range of urea detection from 0.01 to 10 mM with a sensitivity of 29.7 mV per decade.

  17. Comparative study of the kinetics and equilibrium of phenol biosorption on immobilized white-rot fungus Phanerochaete chrysosporium from aqueous solution.

    PubMed

    Farkas, Viktor; Felinger, Attila; Hegedűsova, Alžbeta; Dékány, Imre; Pernyeszi, Tímea

    2013-03-01

    In this study the kinetics and equilibrium of phenol biosorption were studied from aqueous solution using batch technique at an initial pH of 5.5. The biosorption was studied on Ca-alginate beads, on non-living mycelial pellets of Phanerochaete chrysosporium immobilized on Ca-alginate, and on free fungal biomass. Ph. chrysosporium was grown in a liquid medium containing mineral and vitamin materials with complex composition. The biosorption process followed pseudo second-order kinetics on all bioadsorbents. The bioadsorption-equilibrium on blank Ca-alginate, free and immobilized fungal biomass can be described by Langmuir, anti-Langmuir and Freundlich isotherm models using nonlinear least-squares estimation. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    DOE PAGES

    Shaw, Wendy J.

    2014-10-29

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniquesmore » have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area.« less

  19. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    SciTech Connect

    Shaw, Wendy J.

    2014-10-29

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniques have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area.

  20. Immobilization routes - they're not standing still

    SciTech Connect

    Basta, N.

    1982-04-19

    This paper reviews recent developments in the applications of enzyme immobilization techniques in various industries. Following success in high-fructose corn syrup production, enzyme immobilization is now making inroads in food processing and biomass-energy conversion. New studies focus on the immobilization of whole cells.

  1. Solid-state NMR studies of proteins immobilized on inorganic surfaces.

    PubMed

    Shaw, Wendy J

    2015-09-01

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin (43 amino acids) and leucine rich amelogenin protein (LRAP; 59 amino acids), have been studied in depth and have different dynamic properties and 2D- and 3D-structural features. These differences make it difficult to extract design principles used in nature for building materials with properties such as high strength, unusual morphologies, or uncommon phases. Consequently, design principles needed for developing synthetic materials controlled by proteins are not clear. Many biomineralization proteins are much larger than statherin and LRAP, necessitating the study of larger biomineralization proteins. More recent studies of the significantly larger full-length amelogenin (180 residues) represent a significant step forward to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids, a silaffin derived peptide, and the model LK peptide with silica are also being studied, along with qualitative studies of the organic matrices interacting with calcium carbonate. Dipolar recoupling techniques have formed the core of the quantitative studies, yet the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques to study biomineralization proteins is becoming more common, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Ultra-small rhenium nanoparticles immobilized on DNA scaffolds: An excellent material for surface enhanced Raman scattering and catalysis studies.

    PubMed

    Anantharaj, S; Sakthikumar, K; Elangovan, Ayyapan; Ravi, G; Karthik, T; Kundu, Subrata

    2016-12-01

    Highly Sensitive and ultra-small Rhenium (Re) metal nanoparticles (NPs) were successfully stabilized in water by the staging and fencing action of the versatile biomolecule DNA that resulted in two distinct aggregated chain-like morphologies with average grain sizes of 1.1±0.1nm and 0.7±0.1nm for the very first time within a minute of reaction time. Re NPs are formed by the borohydride reduction of ammonium perrhenate (NH4ReO4) in the presence of DNA at room temperature (RT) under stirring. The morphologies were controlled by carefully monitoring the molar ratio of NH4ReO4 and DNA. The synthesized material was employed in two potential applications: as a substrate for surface enhanced Raman scattering (SERS) studies and as a catalyst for the reduction of aromatic nitro compounds. SERS study was carried out by taking methylene blue (MB) as the probe and the highest SERS enhancement factor (EF) of 2.07×10(7) was found for the aggregated chain-like having average grain size of 0.7±0.1nm. Catalytic reduction of 4-nitro phenol (4-NP), 2-nitro phenol (2-NP) and 4-nitroaniline (4-NA) with a rate constant value of 6×10(-2)min(-1), 33.83×10(-2)min(-1) and 37.4×10(-2)min(-1) have testified the excellent catalytic performance of our Re NPs immobilized on DNA. The overall study have revealed the capability of DNA in stabilizing the highly reactive Re metal at nanoscale and made them applicable in practice. The present route can also be extended to prepare one dimensional (1-D), self-assembled NPs of other reactive metals, mixed metals or even metal oxides for specific applications in water based solutions. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography.

    PubMed

    Ma, Liyun; Li, Jing; Zhao, Juan; Liao, Han; Xu, Li; Shi, Zhi-guo

    2016-01-01

    In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions.

  4. A comparative study of the most effective amendment for Pb, Zn and Cd immobilization in contaminated soils.

    PubMed

    Szrek, Dominik; Bajda, Tomasz; Manecki, Maciej

    2011-01-01

    The problem of an extensive contamination of soils with metals can be resolved using an in situ chemical immobilization technology. Five substances (natural zeolite, bog iron ore, "Polifoska 15" fertilizer, triple superphosphate, diammonium phosphate) were tested to determine their efficiency to immobilize Zn, Pb and Cd in smelter-contaminated soil in the Upper Silesia region. Soil samples were collected at three sites located in the vincity of a Pb-Zn smelter and a sludge landfill near the town of Bukowno. Effective reduction of leachable and fitoavailable Zn, Pb and Cd concentrations in soil was observed after addition of diammonium phosphate, "Polifoska 15" fertilizer and bog iron ore amendments. Additional test proved that immobilization effect gained by these amendments sustains at low-temperature conditions. It was noticed that phosphate addition resulted in lowering pH and mobilization of As(V) in soils. Good immobilization effectiveness and lack of major adverse effects of bog iron application suggest that this is the method of choice.

  5. Zinc Oxide Nanoparticles Supported Lipase Immobilization for Biotransformation in Organic Solvents: A Facile Synthesis of Geranyl Acetate, Effect of Operative Variables and Kinetic Study.

    PubMed

    Patel, Vrutika; Shah, Chandani; Deshpande, Milind; Madamwar, Datta

    2016-04-01

    The present study describes grafting of zinc oxide (ZnO) nanoparticles with polyethyleneimine (PEI) followed by modification with glutraldehyde used as the bridge for binding the enzyme to support. The prepared nanocomposites were then characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy, utilized for synthesis of geranyl acetate in n-hexane. Among all the three prepared nanocomposites (ZnO + PEI, ZnO + PEI + SAA, ZnO + PEI + GLU), Candida rugosa lipase immobilized on ZnO-PEI-GLU was found to be best for higher ester synthesis. The operating conditions that maximized geranyl acetate resulted in the highest yield of 94 % in 6 h, molar ratio of 0.1:0.4 M (geraniol/vinyl acetate) in the presence of n-hexane as reaction medium. Various kinetic parameters such as V max, K i(G), K m(G), and K m(VA) were determined using nonlinear regression analysis for order bi-bi mechanism. The kinetic study showed that reaction followed order bi-bi mechanism with inhibition by geraniol. Activation energy (E a ) was found to be lower for immobilized lipase (12.31 kJ mol(-1)) than crude lipase (19.04 kJ mol(-1)) indicating better catalytic efficiency of immobilized lipase. Immobilized biocatalyst demonstrated 2.23-fold increased catalytic activity than crude lipase and recycled 20 times. The studies revealed in this work showed a promising perspective of using low-cost nanobiocatalysts to overcome the well-known drawbacks of the chemical-catalyzed route.

  6. Continuous monitoring of enzymatic reactions on surfaces by real-time flow cytometry: sortase a catalyzed protein immobilization as a case study.

    PubMed

    Heck, Tobias; Pham, Phu-Huy; Hammes, Frederik; Thöny-Meyer, Linda; Richter, Michael

    2014-08-20

    Only a few techniques, such as quartz crystal microbalance and surface plasmon resonance spectroscopy, enable the analysis of dynamic processes on solid supports. Here we have developed a straightforward assay based on flow cytometry to continuously follow enzymatic reactions directly on microparticle surfaces. We applied this real-time flow cytometry (RT-FCM) approach to study the covalent immobilization of green-fluorescent protein (GFPuv) on triglycine-modified polystyrene microbeads by the transpeptidase sortase A (SrtA) from Staphylococcus aureus. Though commonly treated as functionally identical catalysts, the SrtA variants SrtAΔ₅₉ and SrtAΔ₂₅, in which the N-terminal amino acid residues 1-59 and 1-25 of the native enzyme are truncated, were shown to perform very differently with regard to this particular immobilization reaction. While SrtAΔ₅₉ efficiently catalyzed the covalent attachment of GFPuv to the surface (as indicated by a linear increase of microbead fluorescence), SrtAΔ₂₅ was essentially inactive. Besides the length of the N-terminal amino acid extension on the SrtA construct, the position of the hexahistidine tag at either the N- or C-terminus affected the efficiency of enzymatic protein immobilization. Apart from three enzyme variants containing the native core structure of SrtA, we also included three recently evolved mutants of SrtA in this comparative study. With these mutants we observed a rapid initial attachment of the GFPuv target protein to the microbeads. However, with proceeding reaction time, cleavage of the covalently immobilized target protein from the surface prevailed over the coupling reaction, consequently causing a decline of microbead fluorescence. In general, the RT-FCM approach used herein represents a powerful analytical tool for qualitative dynamic studies of many heterogeneous enzymatic reactions or other binding events that influence the fluorescence properties of microparticle surfaces.

  7. Study on immobilization and migration of nuclide u in superficial soil of uranium tailings pond

    NASA Astrophysics Data System (ADS)

    Chang, Zhe; Zhou, Shukui

    2017-05-01

    The uranium tailings in southern China was used as the object of study to study the fixation and migration characteristics of nuclide U in shallow tailings. The results showed that the precipitation of tailings in the tailings soil was not linearly related to the depth during the acid rain leaching process. Tailings soil in the role of fixatives, when the lime as a fixative, the tailings of different soil uranium in 20 days after the re-precipitation. However, when lime and ammonium phosphate were used as fixing agents, the cumulative precipitation of U had a significant effect, and the migration of uranium was inhibited.

  8. Activation and deactivation of a robust immobilized Cp*Ir-transfer hydrogenation catalyst: a multielement in situ X-ray absorption spectroscopy study.

    PubMed

    Sherborne, Grant J; Chapman, Michael R; Blacker, A John; Bourne, Richard A; Chamberlain, Thomas W; Crossley, Benjamin D; Lucas, Stephanie J; McGowan, Patrick C; Newton, Mark A; Screen, Thomas E O; Thompson, Paul; Willans, Charlotte E; Nguyen, Bao N

    2015-04-01

    A highly robust immobilized [Cp*IrCl2]2 precatalyst on Wang resin for transfer hydrogenation, which can be recycled up to 30 times, was studied using a novel combination of X-ray absorption spectroscopy (XAS) at Ir L3-edge, Cl K-edge, and K K-edge. These culminate in in situ XAS experiments that link structural changes of the Ir complex with its catalytic activity and its deactivation. Mercury poisoning and "hot filtration" experiments ruled out leached Ir as the active catalyst. Spectroscopic evidence indicates the exchange of one chloride ligand with an alkoxide to generate the active precatalyst. The exchange of the second chloride ligand, however, leads to a potassium alkoxide-iridate species as the deactivated form of this immobilized catalyst. These findings could be widely applicable to the many homogeneous transfer hydrogenation catalysts with Cp*IrCl substructure.

  9. Immobilization of cobalt(II) Schiff base complexes on polystyrene resin and a study of their catalytic activity for the aerobic oxidation of alcohols.

    PubMed

    Jain, Suman; Reiser, Oliver

    2008-01-01

    The copper-catalyzed [3+2] azide-alkyne cycloaddition and the Staudinger ligation are readily applicable and highly efficient for the immobilization of cobalt Schiff base complexes onto polystyrene resins. Stepwise synthesis of polymer-bound Schiff bases followed by their subsequent complexation with metal ions were successfully carried out. Direct covalent attachment of preformed homogeneous cobalt Schiff base complexes to the resins was also possible. The catalytic efficiency of the so-prepared polystyrene-bound cobalt Schiff bases was studied for the oxidation of alcohols to carbonyl compounds using molecular oxygen as oxidant. The immobilized complexes were highly efficient and even more reactive than the corresponding homogenous analogues, thus affording better yields of oxidized products within shorter reaction times. The supported catalysts could easily be recovered from the reaction mixture by simple filtration and reused for subsequent experiments with consistent catalytic activity.

  10. A comparative study of immobilization techniques for urease on glass-pH-electrode and its application in urea detection in blood serum.

    PubMed

    Sahney, Rachana; Anand, S; Puri, B K; Srivastava, A K

    2006-09-25

    Different techniques have been used (physical adsorption, physically entrapped sandwich and microencapsulation) for the immobilization of urease enzyme in tetramethylorthosilicate (TMOS) derived sol-gel matrix on the sensing surface of glass-pH-electrode. No significant leaching of enzyme occurs from the microencapsulated and physically entrapped enzyme sandwich films. Potentiometric techniques have been used for the estimation of urea concentration in each instance. Various parameters of biosensor performance have been studied which indicates that microencapsulation technique is a better method of enzyme immobilization in sol-gel films derived from TMOS. The advantage of microencapsulated biosensor over others include higher sensitivity (dpH/dp(C)=2.4), lower detection limit of 52 microg mL(-1), larger linear range (0.01-30 mM) of urea determination and reasonably long-term stability of about 25 days with 80% response signal.

  11. Electrochemical Study and Characterization of an Amperometric Biosensor Based on the Immobilization of Laccase in a Nanostructure of TiO₂ Synthesized by the Sol-Gel Method.

    PubMed

    Romero-Arcos, Mariana; Garnica-Romo, Ma Guadalupe; Martínez-Flores, Héctor Eduardo

    2016-07-07

    Laccase amperometric biosensors were developed to detect the catechol compound. The laccase enzyme (LAC) immobilization was performed on nanostructures of (a) titania (TiO₂); (b) titania/Nafion (TiO₂/NAF) (both immobilized by the sol-gel method) and a third nanostructure, which consisted of a single biosensor composite of Nafion and laccase enzyme denoted as NAF/LAC. The Nafion was deposited on a graphite electrode and used to avoid "cracking" on the matrix. The TiO₂ particle size was an average of 66 nm. FTIR spectroscopy vibration modes of different composites were determined. The electrochemical behavior of the biosensor was studied using electrochemical spectroscopy (EIS) and cyclic voltammetry (CV). The biosensor based on TiO₂/NAF/LAC presented the best electro-chemical properties with regard to sensitivity, stability and detection limit after a period of 22 days.

  12. Results of an inter-laboratory study of glass formulation for the immobilization of excess plutonium

    SciTech Connect

    Peeler, D.K.

    1999-12-08

    The primary focus of the current study is to determine allowable loadings of feed streams containing different ratios of plutonium, uranium, and minor components into the LaBS glass and to evaluate thermal stability with respect to the DWPF pour.

  13. [Pathophysiology of immobilization osteoporosis.

    PubMed

    Menuki, Kunitaka; Sakai, Akinori

    Enhancement of bone resorption and suppression of bone formation in response to reduced mechanical stress cause rapid bone loss. pharmacotherapy for immobilization osteoporosis in motor paralysis and long-term bedrest is effective therapy. Early intervention for rapid bone loss is important for immobilization osteoporosis.

  14. An enzyme immobilized microassay in capillary electrophoresis for characterization and inhibition studies of alkaline phosphatases.

    PubMed

    Iqbal, Jamshed

    2011-07-15

    A simple and fast dynamically coated capillary electrophoretic method was developed for the characterization and inhibition studies of alkaline phosphatases(EC 3.1.3.1). An inside capillary enzymatic reaction was performed, and hydrolysis of the substrate 4-nitrophenylphosphate to 4-nitrophenol was measured. Fused-silica capillary surface was dynamically modified with polycationic polybrene coating. By reversal of the electroosmotic flow (EOF), analysis time was reduced up to 3 min as the anionic analytes were migrated in the same direction as the EOF. Furthermore, the sensitivity of the method was increased using electroinjection through high-field amplified injection. The baseline separation of 4-nitrophenylphosphate and 4-nitrophenol was achieved by employing 50 mM sodium phosphate as the running buffer (pH 8.5), 0.0025% polybrene, and a constant voltage of -15 kV, and the products were detected at 322 nm. Under the optimized conditions, a good separation with high efficiency was achieved. The new method was applied to study enzyme kinetics and inhibitor screening. K(m) and K(i) values obtained with the new CE method were compared well with the standard spectrophotometric method. Dynamic coating of fused-silica capillary gave fast and reproducible separation of substrate and product. The method can be easily optimized for inhibition studies of other isozymes.

  15. Spectroelectrochemical study of the [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F in solution and immobilized on biocompatible gold surfaces.

    PubMed

    Millo, Diego; Pandelia, Maria-Eirini; Utesch, Tillmann; Wisitruangsakul, Nattawadee; Mroginski, Maria A; Lubitz, Wolfgang; Hildebrandt, Peter; Zebger, Ingo

    2009-11-19

    The catalytic cycle of the anaerobic [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F (DvMF) both in solution and immobilized on an Au electrode was studied by IR spectroscopic and electrochemical methods. IR spectroelectrochemistry in solution at different pH values allows the identification of the various redox-states of the active site and the determination of the midpoint potentials, as well as their acid-base equilibria. The spectroscopic characterization was based on the unique marker bands of the CN and CO stretching modes of the Ni-Fe center and served as reference for the surface-enhanced IR absorption (SEIRA) study of the immobilized enzyme. Using structural models of hydrogenases from DvMF and Desulfovibrio gigas , dipole moment calculations were carried out to guide the immobilization strategy. In view of the high dipole moment of about 1100 D pointing through the negatively charged area surrounding the distal [FeS] cluster, the Au electrode was coated by a self-assembled monolayer of amino-terminated mercaptanes which, due to the positively charged head groups, permit a durable electrostatic binding of the protein. SEIRA spectroscopy revealed a structurally and functionally intact active site as demonstrated by the reversible activation and inactivation under hydrogen and argon, respectively. Cyclic voltammetry on the immobilized enzyme demonstrate a reversible anaerobic inactivation upon changing the applied potential. The "switch" potential (E(switch)) associated with the reductive reactivation was determined to be -33 mV (vs normal hydrogen electrode). However, the catalytic current decreased on the time scale of hours during continuous cycling. SEIRA experiments demonstrate that the loss of catalytic activity is not due to protein desorption but is rather related to a slow degradation of the active site, possibly initiated by the attack of reactive species electrochemically generated from residual traces of oxygen in solution.

  16. Direct electron transfer and electrochemical study of hemoglobin immobilized in ZnO hollow spheres.

    PubMed

    Liu, Changhua; Xu, Jing; Wu, Zongfang

    2011-10-01

    ZnO hollow spheres were firstly prepared. A new type of amperometric hydrogen peroxide biosensor was fabricated by entrapping Hemoglobin (Hb) through the ZnO hollow spheres (ZHS) nanoparticles. The composition morphology and size were studied by transmission electron microscopy. The surface topography of the prepared films was imaged by atomic force microscope (AFM). Several techniques, including UV-vis absorption spectroscopy, cyclic voltammetry, chronoamperometry were employed to characterize the performance of the biosensor. The results indicated that the ZHS nanoparticles had enhanced the performance of the hydrogen peroxide sensors. The electrochemical parameters of Hb in the ZHS were calculated by the results of the electron-transfer coefficient (α) and the apparent heterogeneous electron-transfer rate constant K (s) as 0.5 and 3.1 s(-1), respectively. The resulting biosensors showed a wide linear range from 2.1 × 10(-6) to 5.18 × 10(-3) M, with a low detection limit of 7.0 × 10(-7) M (S/N = 3) under optimized experimental conditions. The results demonstrated that the ZHS matrix may improve the protein loading with the retention of bioactivity and greatly promote the direct electron transfer, which can be attributed to its unique morphology, high specific surface area, and biocompatibility. The biosensor obtained from this study possesses high sensitivity, good reproducibility, and long-term stability.

  17. Trichloroethylene aerobic cometabolism by suspended and immobilized butane-growing microbial consortia: a kinetic study.

    PubMed

    Frascari, Dario; Zanaroli, Giulio; Bucchi, Giacomo; Rosato, Antonella; Tavanaie, Nasrin; Fraraccio, Serena; Pinelli, Davide; Fava, Fabio

    2013-09-01

    A kinetic study of butane uptake and trichloroethylene (TCE) aerobic cometabolism was conducted by two suspended-cell (15 and 30°C) and two attached-cell (15 and 30°C) consortia obtained from the indigenous biomass of a TCE-contaminated aquifer. The shift from suspended to attached cells resulted in an increase of butane (15 and 30°C) and TCE (15°C) biodegradation rates, and a significant decrease of butane inhibition on TCE biodegradation. The TCE 15°C maximum specific biodegradation rate was equal to 0.011 mg(TCE ) mg(protein)(-1) d(-1) with suspended cells and 0.021 mg(TCE) mg(protein)(-1) d(-1) with attached cells. The type of mutual butane/TCE inhibition depended on temperature and biomass conditions. On the basis of a continuous-flow simulation, a packed-bed PFR inoculated with the 15 or 30°C attached-cell consortium could attain a 99.96% conversion of the studied site's average TCE concentration with a 0.4-0.5-day hydraulic residence time, with a low effect of temperature on the TCE degradation performances.

  18. Pinning of the Contact Line during Evaporation on Heterogeneous Surfaces: Slowdown or Temporary Immobilization? Insights from a Nanoscale Study.

    PubMed

    Zhang, Jianguo; Müller-Plathe, Florian; Leroy, Frédéric

    2015-07-14

    The question of the effect of surface heterogeneities on the evaporation of liquid droplets from solid surfaces is addressed through nonequilibrium molecular dynamics simulations. The mechanism behind contact line pinning which is still unclear is discussed in detail on the nanoscale. Model systems with the Lennard-Jones interaction potential were employed to study the evaporation of nanometer-sized cylindrical droplets from a flat surface. The heterogeneity of the surface was modeled through alternating stripes of equal width but two chemical types. The first type leads to a contact angle of 67°, and the other leads to a contact angle of 115°. The stripe width was varied between 2 and 20 liquid-particle diameters. On the surface with the narrowest stripes, evaporation occurred at constant contact angle as if the surface was homogeneous, with a value of the contact angle as predicted by the regular Cassie-Baxter equation. When the width was increased, the contact angle oscillated during evaporation between two boundaries whose values depend on the stripe width. The evaporation behavior was thus found to be a direct signature of the typical size of the surface heterogeneity domains. The contact angle both at equilibrium and during evaporation could be predicted from a local Cassie-Baxter equation in which the surface composition within a distance of seven fluid-particle diameters around the contact line was considered, confirming the local nature of the interactions that drive the wetting behavior of droplets. More importantly, we propose a nanoscale explanation of pinning during evaporation. Pinning should be interpreted as a drastic slowdown of the contact line dynamics rather than a complete immobilization of it during a transition between two contact angle boundaries.

  19. Pressure ulcers, indentation marks and pain from cervical spine immobilization with extrication collars and headblocks: An observational study.

    PubMed

    Ham, Wietske H W; Schoonhoven, Lisette; Schuurmans, Marieke J; Leenen, Luke P H

    2016-09-01

    To describe the occurrence and severity of pressure ulcers, indentation marks and pain from the extrication collar combined with headblocks. Furthermore, the influence of time, injury severity and patient characteristics on the development of pressure ulcers, indentation marks and pain was explored. Observational. Level one trauma centre in the Netherlands. Adult trauma patients admitted to the Emergency Department in an extrication collar combined with headblocks. Between January and December 2013, 342 patients were included. Study outcomes were incidence and severity of pressure ulcers, indentation marks and pain. The following dependent variables were collected: time in the cervical collar and headblocks, Glasgow Coma Scale, Mean Arterial Pressure, haemoglobin, Injury Severity Score, gender, age, and Body Mass Index. 75.4% of the patients developed a category 1 and 2.9% a category 2 pressure ulcer. Indentation marks were observed in 221 (64.6%) patients; 96 (28.1%) had severe indentation marks. Pressure ulcers and indentation marks were observed most frequently at the back, shoulders and chest. 63.2% experienced pain, of which, 38.5% experienced severe pain. Pain was mainly located at the occiput. Female patients experienced significantly more pain (NRS>3) compared to male patients (OR=2.14, 95% CI 1.21-3.80) None of the investigated variables significantly increased the probability of developing PUs or indentation marks. The high incidence of category 1 pressure ulcers and severe indentation marks indicate an increased risk for pressure ulcer development and may well lead to more severe PU lesions. Pain due to the application of the extrication collar and headblocks may lead to undesirable movement (in order to relieve the pressure) or to bias clinical examination of the cervical spine. It is necessary to revise the current practice of cervical spine immobilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Studying MHC class II presentation of immobilized antigen by B lymphocytes.

    PubMed

    Yuseff, M I; Lennon-Dumenil, A M

    2013-01-01

    The ability of B lymphocytes to capture external antigens (Ag) and present them as peptide fragments, loaded on Major Histocompatibility complex (MHC) class II molecules, to CD4(+) T cells is a crucial part of the adaptive immune response. This allows T-B cooperation, a cellular communication that is required for B cells to develop into germinal centers (GC) and form mature high-affinity antibody producing cells and to further develop B cell memory. MHC class II antigen presentation by B lymphocytes is a multistep process involving (1) Recognition and capture of external Ag by B lymphocytes through their B cell receptor (BCR); (2) Ag processing, which comprises the degradation of Ag in internal compartments within the B cell and loading of the corresponding peptide fragments on MHC class II molecules and (3) Presentation of MHC II-peptide complexes to CD4(+) T cells. Here, we describe how to study MHC class II antigen presentation by B lymphocytes at these three major levels.

  1. A nanoparticle-based immobilization assay for prion-kinetics study

    PubMed Central

    Kouassi, Gilles K; Irudayaraj, Joseph

    2006-01-01

    Magnetic and gold coated magnetic nanoparticles were synthesized by co-precipitation of ferrous and ferric chlorides, and by the micromicelles method, respectively. Synthesized nanoparticles were functionalized to bear carboxyl and amino acid moieties and used as prion protein carriers after carbodiimide activation in the presence of N-hydroxysuccinimide. The binding of human recombinant prion protein (huPrPrec) to the surface of these nanoparticles was confirmed by FTIR and the size and structures of the particles were characterized by transmission electron microscopy. Findings indicate that the rate of prion binding increased only slightly when the concentration of prion in the reaction medium was increased. Rate constants of binding were very similar on Fe3O4@Au and Fe3O4-LAA when the concentrations of protein were 1, 2, 1.5, 2.25 and 3.57 μg/ml. For a 5 μg/ml concentration of huPrPrec the binding rate constant was higher for the Fe3O4-LAA particles. This study paves the way towards the formation of prion protein complexes onto a 3-dimensional structure that could reveal obscure physiological and pathological structure and prion protein kinetics. PMID:16916458

  2. A kinetic study of bitter taste receptor sensing using immobilized porcine taste bud tissues.

    PubMed

    Wei, Lihui; Qiao, Lixin; Pang, Guangchang; Xie, Junbo

    2017-06-15

    At present, developing an efficient assay method for truly reflecting the real feelings of gustatory tissues is of great importance. In this study, a novel biosensor was fabricated to investigate the kinetic characteristics of the receptors in taste bud tissues sensing bitter substances for the first time. Porcine taste bud tissues were used as the sensing elements, and the sandwich-type sensing membrane was fixed onto a glassy carbon electrode for assembling the biosensor. With the developed sensor, the response currents induced by sucrose octaacetate, denatonium benzoate, and quercetin stimulating corresponding receptors were determined. The results demonstrated that the interaction between the analyst with their receptors were fitting to hyperbola (R(2)=0.9776, 0.9980 and 0.9601), and the activation constants were 8.748×10(-15)mol/L, 1.429×10(-12)mol/L, 6.613×10(-14)mol/L, respectively. The average number of receptors per cell was calculated as 1.75, 28.58, and 13.23, while the signal amplification factors were 1.08×10(4), 2.89×10(3) and 9.76×10(4). These suggest that the sensor can be used to quantitatively describe the interaction characteristics of cells or tissue receptors with their ligands, the role of cellular signaling cascade, the number of receptors, and the signal transmission pathways. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Study on the immobilization of anti-IgG on Au-colloid modified gold electrode via potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques.

    PubMed

    Fu, Yingzi; Yuan, Ruo; Tang, Dianping; Chai, Yaqin; Xu, Lan

    2005-01-15

    The immobilization of anti-IgG on Au-colloid modified gold electrodes has been investigated. A cleaned gold electrode was first immersed in a mercaptoethylamine (AET) solution, and then gold nanoparticles were chemisorbed onto the thiol groups of the mercaptoethylamine. Finally, anti-IgG was adsorbed onto the surface of the gold nanoparticles. Potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques were used to investigate the immobilization of anti-IgG on Au colloids. In the impedance spectroscopic study, an obvious difference of the electron transfer resistance between the Au-colloid modified electrode and the bare gold electrode was observed. The cyclic voltammogram tends to be more irreversible with increased anti-IgG concentration. Using the potentiometric immunosensor, the proposed technique is based on that the specific agglutination of antibody-coated gold nanoparticles, averaging 16 nm in diameter, in the presence of the corresponding antigen causes a potential change that is monitored by a potentiometry. It is found that the developed immunoagglutination assay system is sensitive to the concentration of IgG antigen as low as 12 ng mL(-1). Experimental results showed that the developed technique is in satisfactory agreement with the ELISA method, and that gold nanoparticles can be used as a biocompatible matrix for antibody or antigen immobilization.

  4. An electrochemical quartz crystal impedance study on anti-human immunoglobulin G immobilization in the polymer grown during dopamine oxidation at an Au electrode.

    PubMed

    He, Hua; Xie, Qingji; Yao, Shouzhuo

    2005-09-15

    The polymeric film grown during dopamine oxidation at an Au electrode was studied as a novel matrix for immobilizing anti-human immunoglobulin G (IgG) via the electrochemical quartz crystal impedance analysis (EQCIA) method. The growth of the polymeric films at Au electrodes during dopamine oxidation in neutral phosphate buffer (pH 7.4) and the immobilization of anti-human IgG into the polymeric films during their growth have been traced at real time. Lysozyme control experiments suggested that anti-human IgG was electrostatically incorporated into the polymeric film. Also, the porosity of the polymeric films has been discussed by measuring the "wet" and "dry" frequency shifts. Compared with a polypyrrole film immobilized with anti-human IgG, the proposed matrix possessed a larger amount of specific binding sites for human IgG by subsequent immunoreaction tests. The association constant of the anti-human IgG immunoreaction was obtained with satisfactory results.

  5. Immobilization of excess weapons plutonium in Russia

    SciTech Connect

    Borisov, G B; Jardine, L J; Mansourov, O A

    1999-01-25

    In this paper, we examine the logic and framework for the development of a capability to immobilize excess Russian weapons plutonium by the year 2004. The initial activities underway in Russia, summarized here, include engineering feasibility studies of the immobilization of plutonium-containing materials at the Krasnoyarsk and Mayak industrial sites. In addition, research and development (R&D) studies are underway at Russian institutes to develop glass and ceramic forms suitable for the immobilization of plutonium-containing materials, residues, and wastes and for their geologic disposal.

  6. Plutonium Disposition by Immobilization

    SciTech Connect

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

    2000-03-07

    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&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&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&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.

  7. Study of whey fermentation by kefir immobilized on low cost supports using 14C-labelled lactose.

    PubMed

    Soupioni, Magdalini; Golfinopoulos, Aristidis; Kanellaki, Maria; Koutinas, Athanasios A

    2013-10-01

    Brewer's Spent Grains (BSG) and Malt Spent Rootlets (MSR) were used as supports for kefir cells immobilization and the role of lactose uptake rate by kefir in the positive activity of produced biocatalysts during whey fermentation was investigated. Lactose uptake rate by the immobilized cells was recorded using (14)C-labelled lactose and the effect of various conditions (pH, temperature and kind of support) on it and consequently on fermentation time and ethanol production was examined. The results showed that lactose uptake rate was correlated to fermentation rate and increased as temperature was increased up to 30°C at pH 5.5. The same results have been recently noticed by using biocatalysts with Delignified Cellulosic Materials (DCM) and Gluten Pellets (GP), but fermentation time of about 7h by kefir immobilized on DCM and BSG resulted to two fold lower than that on GP and MSR. The highest alcohol concentration was observed by MSR. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Immobilization of phenanthrene onto gemini surfactant modified sepiolite at solid/aqueous interface: Equilibrium, thermodynamic and kinetic studies.

    PubMed

    Zhao, Shan; Huang, Guohe; Mu, Sen; An, Chunjiang; Chen, Xiujuan

    2017-11-15

    The immobilization of phenanthrene from aqueous phase onto natural and gemini surfactant modified sepiolite was investigated with respect to contact time, pH, ionic strength and temperature. The surface modification was examined through FT-IR characterization, SEM technique, and the thermogravimetric analysis. The maximum sorption capacity of phenanthrene on modified sepiolite was 95.15μgg(-1) with initial PHE concentration 1.0mgL(-1), temperature 293K, pH7, and ionic strength 1M. The corresponding PHE removal efficiency was higher than 95%. The Langmuir, Freundlich and Temkin isotherm models were applied to describe the phenanthrene sorption behavior and the Freundlich equation agreed well with the experimental data. The evaluation of the thermodynamic parameters indicated that the immobilization of phenanthrene onto gemini surfactant modified sepiolite was a spontaneous and exothermic process from 283 to 313K. The pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models were used to evaluate the kinetic data. According to the calculated kinetic parameters, the immobilization process of phenanthrene followed the Elovich kinetic model with the highest correlation coefficients. The obtained results show that gemini surfactant modified sepiolite could be effectively utilized as one type of low-cost clay material to remove polycyclic aromatic hydrocarbons from water effluents. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Free and Ca-Alginate Beads Immobilized Horseradish Peroxidase for the Removal of Reactive Dyes: an Experimental and Modeling Study.

    PubMed

    Farias, Simone; Mayer, Diego A; de Oliveira, Débora; de Souza, Selene M A Guelli U; de Souza, Antônio Augusto Ulson

    2017-08-01

    The aim of this work was to remove the dyes Reactive Blue 221 (RB 221) and Reactive Blue 198 (RB 198) of synthetic effluent using the immobilized enzyme horseradish peroxidase (HRP) in Ca-alginate beads. Experimental parameters affecting the dye removal process such as the effect of pH, temperature, hydrogen peroxide concentration, mass capsules, and reuse were evaluated, and a numerical model of mass transfer was developed. A maximum removal of 93 and 75%, respectively, for the dyes RB 221 and RB 198, at pH 5.5 and temperature of 30 °C, concentration of hydrogen peroxide of 43.75 μM for dye RB 221 and 37.5 μM for the dye of RB 198 was obtained. A removal reaction of 180 min for RB 221 and 240 min for RB 198 was observed. Three reuse cycles of use of immobilized enzyme were achieved for both dyes. The numerical model proposed led to a good fit compared to experimental data. The HRP enzyme immobilized in Ca-alginate capsules showed a great potential for biotechnological applications, especially for the removal of reactive dyes.

  10. Waste/soil treatability studies for four complex industrial wastes: methodologies and results. Volume 2. Waste loading impacts on soil degradation, transformation, and immobilization. Final report

    SciTech Connect

    Sims, R.C.; Sorensen, D.L.; Doucette, W.J.; Hastings, L.L.; Sims, J.L.

    1986-10-01

    The two-volume report presents information pertaining to quantitative evaluation of the soil-treatment potential resulting from waste-soil interaction studies for four specific wastes listed under Section 3001 of the Resource Conservation and Recovery Act. Volume 2 contains results from bench-scale waste-soil interaction studies; degradation, transformation, and immobilization data are presented for four specific wastes: API separator sludge, slop oil emulsion solids, pentachlorophenol wood preserving waste, and creosote wood-preserving waste. The scope of the study involved assessment of the potential for treatment of these hazardous wastes using soil as the treatment medium.

  11. Immobilization of Peroxidase onto Magnetite Modified Polyaniline

    PubMed Central

    Barbosa, Eduardo Fernandes; Molina, Fernando Javier; Lopes, Flavio Marques; García-Ruíz, Pedro Antonio; Caramori, Samantha Salomão; Fernandes, Kátia Flávia

    2012-01-01

    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. PMID:22489198

  12. Immobilization induced hypercalcemia

    PubMed Central

    Cano-Torres, Edgar Alonso; González-Cantú, Arnulfo; Hinojosa-Garza, Gabriela; Castilleja-Leal, Fernando

    2016-01-01

    Summary Immobilization hypercalcemia is an uncommon diagnosis associated with increased bone remodeling disorders and conditions associated with limited movement such as medullar lesions or vascular events. Diagnosis requires an extensive evaluation to rule out other causes of hypercalcemia. This is a report of a woman with prolonged immobilization who presented with severe hypercalcemia. This case contributes to identification of severe hypercalcemia as a result of immobility and the description of bone metabolism during this state. PMID:27252745

  13. Inter- and Intrafraction Patient Positioning Uncertainties for Intracranial Radiotherapy: A Study of Four Frameless, Thermoplastic Mask-Based Immobilization Strategies Using Daily Cone-Beam CT

    SciTech Connect

    Tryggestad, Erik; Christian, Matthew; Ford, Eric; Kut, Carmen; Le Yi; Sanguineti, Giuseppe; Song, Danny Y.; Kleinberg, Lawrence

    2011-05-01

    Purpose: To determine whether frameless thermoplastic mask-based immobilization is adequate for image-guided cranial radiosurgery. Methods and Materials: Cone-beam CT localization data from patients with intracranial tumors were studied using daily pre- and posttreatment scans. The systems studied were (1) Type-S IMRT (head only) mask (Civco) with head cushion; (2) Uni-Frame mask (Civco) with head cushion, coupled with a BlueBag body immobilizer (Medical Intelligence); (3) Type-S head and shoulder mask with head and shoulder cushion (Civco); (4) same as previous, coupled with a mouthpiece. The comparative metrics were translational shift magnitude and average rotation angle; systematic inter-, random inter-, and random intrafraction positioning error was computed. For strategies 1-4, respectively, the analysis for interfraction variability included data from 20, 9, 81, and 11 patients, whereas that for intrafraction variability included a subset of 7, 9, 16, and 8 patients. The results were compared for statistical significance using an analysis of variance test. Results: Immobilization system 4 provided the best overall accuracy and stability. The mean interfraction translational shifts ({+-} SD) were 2.3 ({+-} 1.4), 2.2 ({+-} 1.1), 2.7 ({+-} 1.5), and 2.1 ({+-} 1.0) mm whereas intrafraction motion was 1.1 ({+-} 1.2), 1.1 ({+-} 1.1), 0.7 ({+-} 0.9), and 0.7 ({+-} 0.8) mm for devices 1-4, respectively. No significant correlation between intrafraction motion and treatment time was evident, although intrafraction motion was not purely random. Conclusions: We find that all frameless thermoplastic mask systems studied are viable solutions for image-guided intracranial radiosurgery. With daily pretreatment corrections, symmetric PTV margins of 1 mm would likely be adequate if ideal radiation planning and targeting systems were available.

  14. Diffusion of solutes inside bacterial colonies immobilized in model cheese depends on their physicochemical properties: a time-lapse microscopy study

    PubMed Central

    Floury, Juliane; El Mourdi, Ilham; Silva, Juliana V. C.; Lortal, Sylvie; Thierry, Anne; Jeanson, Sophie

    2015-01-01

    During cheese processing and ripening, bacteria develop as colonies. Substrates and metabolites must then diffuse either from or into the colonies. Exploring how the inner cells of the colony access the substrates or get rid of the products leads to study the diffusion of solutes inside bacterial colonies immobilized in cheese. Diffusion limitations of substrates within the bacterial colony could lead to starvation for the cells in the center of the colony. This study aimed at better understands ripening at the colony level, by investigating how diffusion phenomena inside colonies vary depending on both the physicochemical properties of the solutes and Lactococcus lactis strain. Dextrans (4, 70, and 155 kDa) and milk proteins (BSA, lactoferrin and αS1-casein) of different sizes and physicochemical properties were chosen as model of diffusing solutes, and two L. lactis strains presenting different surface properties were immobilized as colonies in a model cheese. Diffusion of solutes inside and around colonies was experimentally followed by time-lapse confocal microscopy. Dextran solutes diffused inside both lactococci colonies with a non-significantly different effective diffusion coefficient, which depended mainly on size of the solute. However, whereas flexible and neutral hydrophilic polymers such as dextran can diffuse inside colonies whatever its size, none of the three proteins investigated in this study could penetrate inside lactococci colonies. Therefore, the diffusion behavior of macromolecules through bacterial colonies immobilized in a model cheese did not only depends on the size of the diffusing solutes, but also and mainly on their physicochemical properties. Milk caseins are probably first hydrolyzed by the cell wall proteases of L. lactis and/or other proteases present in the cheese, and then the generated peptides diffuse inside colonies to be further metabolized into smaller peptides and amino acids by all the cells located inside the colonies

  15. Effectiveness of olive oil for the prevention of pressure ulcers caused in immobilized patients within the scope of primary health care: study protocol for a randomized controlled trial.

    PubMed

    Lupiáñez-Pérez, Inmaculada; Morilla-Herrera, Juan Carlos; Ginel-Mendoza, Leovigildo; Martín-Santos, Francisco Javier; Navarro-Moya, Francisco Javier; Sepúlveda-Guerra, Rafaela Pilar; Vázquez-Cerdeiros, Rosa; Cuevas-Fernández-Gallego, Magdalena; Benítez-Serrano, Isabel María; Lupiáñez-Pérez, Yolanda; Morales-Asencio, José Miguel

    2013-10-23

    Pressure ulcers are considered an important issue, mainly affecting immobilized older patients. These pressure ulcers increase the care burden for the professional health service staff as well as pharmaceutical expenditure. There are a number of studies on the effectiveness of different products used for the prevention of pressure ulcers; however, most of these studies were carried out at a hospital level, basically using hyperoxygenated fatty acids (HOFA). There are no studies focused specifically on the use of olive-oil-based products and therefore this research is intended to find the most cost-effective treatment and achieve an alternative treatment. The main objective is to assess the effectiveness of olive oil, comparing it with HOFA, to treat immobilized patients at home who are at risk of pressure ulcers. As a secondary objective, the cost-effectiveness balance of this new application with regard to the HOFA will be assessed. The study is designed as a noninferiority, triple-blinded, parallel, multi-center, randomized clinical trial. The scope of the study is the population attending primary health centers in Andalucía (Spain) in the regional areas of Malaga, Granada, Seville, and Cadiz. Immobilized patients at risk of pressure ulcers will be targeted. The target group will be treated by application of an olive-oil-based formula whereas the control group will be treated by application of HOFA to the control group. The follow-up period will be 16 weeks. The main variable will be the presence of pressure ulcers in the patient. Secondary variables include sociodemographic and clinical information, caregiver information, and whether technical support exists. Statistical analysis will include the Kolmogorov-Smirnov test, symmetry and kurtosis analysis, bivariate analysis using the Student's t and chi-squared tests as well as the Wilcoxon and the Man-Whitney U tests, ANOVA and multivariate logistic regression analysis. The regular use of olive-oil-based formulas

  16. Effectiveness of olive oil for the prevention of pressure ulcers caused in immobilized patients within the scope of primary health care: study protocol for a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Pressure ulcers are considered an important issue, mainly affecting immobilized older patients. These pressure ulcers increase the care burden for the professional health service staff as well as pharmaceutical expenditure. There are a number of studies on the effectiveness of different products used for the prevention of pressure ulcers; however, most of these studies were carried out at a hospital level, basically using hyperoxygenated fatty acids (HOFA). There are no studies focused specifically on the use of olive-oil-based products and therefore this research is intended to find the most cost-effective treatment and achieve an alternative treatment. Methods/design The main objective is to assess the effectiveness of olive oil, comparing it with HOFA, to treat immobilized patients at home who are at risk of pressure ulcers. As a secondary objective, the cost-effectiveness balance of this new application with regard to the HOFA will be assessed. The study is designed as a noninferiority, triple-blinded, parallel, multi-center, randomized clinical trial. The scope of the study is the population attending primary health centers in Andalucía (Spain) in the regional areas of Malaga, Granada, Seville, and Cadiz. Immobilized patients at risk of pressure ulcers will be targeted. The target group will be treated by application of an olive-oil-based formula whereas the control group will be treated by application of HOFA to the control group. The follow-up period will be 16 weeks. The main variable will be the presence of pressure ulcers in the patient. Secondary variables include sociodemographic and clinical information, caregiver information, and whether technical support exists. Statistical analysis will include the Kolmogorov-Smirnov test, symmetry and kurtosis analysis, bivariate analysis using the Student’s t and chi-squared tests as well as the Wilcoxon and the Man-Whitney U tests, ANOVA and multivariate logistic regression analysis. Discussion The

  17. Carbodiimide for Covalent α-Amylase Immobilization onto Magnetic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Milani, Zeinab Mortazavi; Jalal, Razieh; Goharshadi, Elaheh K.

    Covalent cross-linking of enzymes to magnetite (Fe3O4) nanoparticles (MNPs) is one of the useful enzyme immobilization methods which provides repeated use of the catalyst, facilitates enzyme separation from the reaction mixture, and sometimes improves biocatalysts stability. The aim of this study was to immobilize α-amylase onto MNPs via covalent attachment using carbodiimide (CDI) molecules. MNPs were synthesized by the co-precipitation method. The size and the structure of the particles were characterized by X-ray diffraction and transmission electron microscopy. The effects of different operational conditions of direct α-amylase binding on MNPs in the presence of CDI were investigated by using the shaking method. Fourier transform infrared spectroscopy was used to confirm the success of immobilization. The optimum conditions and catalytic properties of immobilized α-amylase were also evaluated. The efficiency of immobilization and the residual activity of the immobilized α-amylase were dependent on the mass ratio of MNPs: CDI: α-amylase and the immobilization temperature. The optimum pH for the free and immobilized amylase was 6. The free and immobilized α-amylase showed maximum activity at 20∘C and 35∘C, respectively. The immobilized α-amylase was more thermostable than the free one. The retained activity for free α-amylase after 19 storage days was 57.7% whereas it was 100% for the immobilized α-amylase. In repeated batch experiments, the immobilized α-amylase retained a residual activity of 45% after 11 repeated uses. The Km and Vmax values for the immobilized enzyme were larger than those of the free enzyme. The immobilization of α-amylase on MNPs using CDI improves its stability and reusability.

  18. Preparation and properties of immobilized lipoprotein lipase.

    PubMed

    Matsuoka, N; Shirai, K; Jackson, R L

    1980-11-07

    Purified bovine milk lipoprotein lipase has been covalently attached to CH-Sepharose with water-soluble carbodiimide. The immobilized enzyme retained enzymic activity and was stimulated 7-fold by the addition of human apolipoprotein C-II. Both [3H]heparin and 125I-labeled apolipoprotein C-II bound to the immobilized enzyme; unlabeled heparin and apolipoprotein C-II competed for binding of their respective labeled compounds. Apolipoprotein C-II did not compete for binding of [3H]heparin and vice versa. Human apolipoprotein C-III did not bind to the immobilized enzyme nor did it compete for apolipoprotein C-II binding. We conclude from these studies that both apolipoprotein C-II and heparin interact with immobilized lipoprotein lipase and that they have different binding sites.

  19. Effect of fermentation parameters on bio-alcohols production from glycerol using immobilized Clostridium pasteurianum: an optimization study.

    PubMed

    Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

    2013-01-01

    This article addresses the issue of effect of fermentation parameters for conversion of glycerol (in both pure and crude form) into three value-added products, namely, ethanol, butanol, and 1,3-propanediol (1,3-PDO), by immobilized Clostridium pasteurianum and thereby addresses the statistical optimization of this process. The analysis of effect of different process parameters such as agitation rate, fermentation temperature, medium pH, and initial glycerol concentration indicated that medium pH was the most critical factor for total alcohols production in case of pure glycerol as fermentation substrate. On the other hand, initial glycerol concentration was the most significant factor for fermentation with crude glycerol. An interesting observation was that the optimized set of fermentation parameters was found to be independent of the type of glycerol (either pure or crude) used. At optimum conditions of agitation rate (200 rpm), initial glycerol concentration (25 g/L), fermentation temperature (30°C), and medium pH (7.0), the total alcohols production was almost equal in anaerobic shake flasks and 2-L bioreactor. This essentially means that at optimum process parameters, the scale of operation does not affect the output of the process. The immobilized cells could be reused for multiple cycles for both pure and crude glycerol fermentation.

  20. Study of the potential of the air lift bioreactor for xylitol production in fed-batch cultures by Debaryomyces hansenii immobilized in alginate beads.

    PubMed

    Pérez-Bibbins, Belinda; de Souza Oliveira, Ricardo Pinheiro; Torrado, Ana; Aguilar-Uscanga, María Guadalupe; Domínguez, José Manuel

    2014-01-01

    Cell immobilization has shown to be especially adequate for xylitol production. This work studies the suitability of the air lift bioreactor for xylitol production by Debaryomyces hansenii immobilized in Ca-alginate operating in fed-batch cultures to avoid substrate inhibition. The results showed that the air lift bioreactor is an adequate system since the minimum air flow required for fluidization was even lower than that leading to the microaerobic conditions that trigger xylitol accumulation by this yeast, also maintaining the integrity of the alginate beads and the viability of the immobilized cells until 3 months of reuses. Maximum productivities and yields of 0.43 g/l/h and 0.71 g/g were achieved with a xylose concentration of 60 g/l after each feeding. The xylose feeding rate, the air flow, and the biomass concentration at the beginning of the fed-batch operation have shown to be critical parameters for achieving high productivities and yields. Although a maximum xylitol production of 139 g/l was obtained, product inhibition was evidenced in batch experiments, which allowed estimating at 200 and 275 g/l the IC50 for xylitol productivity and yield, respectively. The remarkable production of glycerol in the absence of glucose was noticeable, which could not only be attributed to the osmoregulatory function of this polyol in conditions of high osmotic pressure caused by high xylitol concentrations but also to the role of the glycerol synthesis pathway in the regeneration of NAD(+) in conditions of suboptimal microaeration caused by insufficient aeration or high oxygen demand when high biomass concentrations were achieved.

  1. (Immobilization of radioactive wastes)

    SciTech Connect

    Dole, L.R.

    1986-12-18

    The traveler participated as the co-chairman of the France/US Workshop in Cadarache, France, on the immobilization of radioactive wastes in cement-based materials. These meetings and site visits were conducted under the bilateral exchange agreement between the US-DOE and the Commissariate a l'Energie Atomique (CEA-France). Visits in France included the Cadarache, Valduc, Saclay, and Fontenay-aux-Roses Nuclear Research Centers. As a result of these discussions, an exchange of scientists between Saclay and ORNL was proposed. The traveler continued on to the FRG to visit a hazardous waste site remedial action project in Sprendlingen and the nuclear research and production facilities at the Karlsruhe Kernforschungszentrum (KfK) and the Alkem/Nukem/Transnuklear facilities at Hanau. Visits in the FRG were under the bilateral exchange agreement between the US-DOE and the Bundes Ministerium fur Forschung und Technologie (BMFT). The FRG supplied the traveler data on studies of super-compaction volume reduction efficiencies by KfK and Nukem. Also, Transnuklear is considering contributing two of their larger Konrad-certified packages to the MDU studies at ORNL. 1 tab.

  2. Equilibrium isotherm and kinetic studies for the simultaneous removal of phenol and cyanide by use of S. odorifera (MTCC 5700) immobilized on coconut shell activated carbon

    NASA Astrophysics Data System (ADS)

    Singh, Neetu; Balomajumder, Chandrajit

    2016-09-01

    In this study, simultaneous removal of phenol and cyanide by a microorganism S. odorifera (MTCC 5700) immobilized onto coconut shell activated carbon surface (CSAC) was studied in batch reactor from mono and binary component aqueous solution. Activated carbon was derived from coconut shell by chemical activation method. Ferric chloride (Fecl3), used as surface modification agents was applied to biomass. Optimum biosorption conditions were obtained as a function of biosorbent dosage, pH, temperature, contact time and initial phenol and cyanide concentration. To define the equilibrium isotherms, experimental data were analyzed by five mono component isotherm and six binary component isotherm models. The higher uptake capacity of phenol and cyanide onto CSAC biosorbent surface was 450.02 and 2.58 mg/g, respectively. Nonlinear regression analysis was used for determining the best fit model on the basis of error functions and also for calculating the parameters involved in kinetic and isotherm models. The kinetic study results revealed that Fractal-like mixed first second order model and Brouser-Weron-Sototlongo models for phenol and cyanide were capable to offer accurate explanation of biosorption kinetic. According to the experimental data results, CSAC with immobilization of bacterium S. odorifera (MTCC 5700) seems to be an alternative and effective biosorbent for the elimination of phenol and cyanide from binary component aqueous solution.

  3. Immobilized enzymes in organic synthesis.

    PubMed

    Mosbach, K

    1985-01-01

    The immobilization of enzymes and cells by different methods and the possible stabilization of immobilized preparations are discussed. An outlook on 'second generation enzyme technology', which involves immobilized multi-enzyme systems and coenzymes, is given with examples: the immobilization of dehydrogenases with their active sites facing one another, and systems containing NAD(H) coenzymes immobilized by coupling to dextran (in an enzyme electrode), to polyethylene glycol (in a membrane reactor), or to enzymes themselves. The use of immobilized enzymes to synthesize peptides and disaccharides is described.

  4. Biotechnological production of vanillin using immobilized enzymes.

    PubMed

    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.

  5. [Biodegradation of dibutyl phthalate by diatomite adsorptive immobilized microorganism].

    PubMed

    Wang, Lin; Luo, Qi-Fang

    2006-01-01

    To study the biodegradation characteristics of seeding type immobilized microorganism on dibutyl phthalate (DBP). The immobilized microorganism was made to adsorb DBP degradation dominant bacteria by using modified diatomite as carrier, then it degraded DBP under different primary concentration, vibration rate, pH, temperature and at the presence of metal compounds. The degradation kinetics was analyzed. When DBP primary concentration was 100-500 mg/L, the adsorptive immobilized microorganism could maintain relatively high activity and the DBP degraded rate was above 80% in 24h. Dissociative and immobilized microorganism could get higher degradation activity in vibration than in stillness. When pH was 6.0 - 9.0, the degradation rate of immobilized microorganism on DBP was above 82% in 24h and its activity is higher than dissociative microorganism. In the range of 20 degrees C to 40 degrees C, the DBP degraded rate by immobilized microorganism could reach 84.5% in 24h. If mental compounds existed in the DBP water sample, the degradation activities of dissociative and immobilized microorganism were inhibited obviously. The form of DBP degradation kinetics could be described as the first-order model. The immobilized microorganisms using diatomite as carrier could degrade DBP effectively. The adsorptive immobilized microorganism was more adapted to DBP load, temperature and pH than dissociative microorganism. The mental compounds could inhibited their activities. The degradation reaction of adsorptive immobilized microorganisms on DBP was according with the first-order model.

  6. Comparative study on functionalized SBA-15 and SBA-16 nanostructured materials used for immobilization of D-amino acid oxidase

    NASA Astrophysics Data System (ADS)

    Hy, Le Gia; Phuong, Dang Tuyet; Yen, Hoang; Hoan, Nguyen Thi Vuong; Linh, Bui Thi Hai; Thang, Hoang vinh; Hoa, Tran Thi Kim; Thang, Dinh Cao; Nguyen, Vu Thi Hanh; Thao, Phan Thi Hong; Giap, Chu Van; Tuan, Vu Anh

    2008-12-01

    SBA-15 and SBA-16 nanostucrured materials were synthesized via hydrothermal treatment and were functionalized with 3-aminopropyltriethoxysilane (APTES), and vinyltriethoxysilane (VTES). The obtained samples were characterized by different techniques such as XRD, BET, IR and TEM. After functionalization, it showed that these nanostrucrured materials were still maintained the hexagonal pore structure of the parent SBA-15 and cubic cage structure of the parent SBA-16. The non-functionalized pure silica SBA-15 and SBA-16 as well as functionalized SBA-15 and SBA-16 materials were used to immobilize DAAO, which is industrially important enzyme for the production of glutaryl 7-amino cephalosporanic acid (GL-7-ACA) from cephalosporin C (CPC). The obtained results revealed that functionalized SBA- 15 and SBA-16 materials exhibited higher enzymatic activity and stability than those of non-functionalized ones. This might be due to the enhancing of surface hydrophobicity upon functionalization. The surface functionalization of the nanostructured silicas with organic groups can enhance the interaction between enzyme and the supports and consequently increasing the operational stability of the immobilized enzyme. The loading of enzyme on SBA-15 materials was higher than that on SBA-16 samples (both functionalized and non-functionalized types). This might be explained by the difference in pore size and type (cylindrical for SBA-15 and bottle-neck for SBA-16) as well as structure shape (hexagonal for SBA-15 and cubic cage for SBA-16) of both mesoporous materials. Additionally, nature of functionalized groups significantly affected the enzymatic activity. Effects on surface binding force, nature of functional groups, pore size of supports were investigated and discussed.

  7. Ultra-low field T1 vs. T1rho at 3T and 7T: study of rotationally immobilized protein gels and animal brain tissues

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Inglis, Ben; Barr, Ian; Clarke, John

    2015-03-01

    Clinical magnetic resonance imaging (MRI) machines operating in static fields of typically 1.5 T or 3 T can capture information on slow molecular dynamics utilizing the so-called T1rho technique. This technique, in which a radiofrequency (RF) spin-lock field is applied with microtesla amplitude, has been used, for example, to determine the onset time of stroke in studies on rats. The long RF pulse, however, may exceed the specific absorption rate (SAR) limit, putting subjects at risk. Ultra-low-field (ULF) MRI, based on Superconducting Quantum Interference Devices (SQUIDs), directly detects proton signals at a static magnetic field of typically 50-250 μT. Using our ULF MRI system with adjustable static field of typically 55 to 240 μT, we systematically measured the T1 and T2 dispersion profiles of rotationally immobilized protein gels (bovine serum albumin), ex vivo pig brains, and ex vivo rat brains with induced stroke. Comparing the ULF results with T1rho dispersion obtained at 3 T and 7 T, we find that the degree of protein immobilization determines the frequency-dependence of both T1 and T1rho. Furthermore, T1rho and ULF T1 show similar results for stroke, suggesting that ULF MRI may be used to image traumatic brain injury with negligible SAR. This research was supported by the Henry H. Wheeler, Jr. Brain Imaging Center and the Donaldson Trust.

  8. An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

    PubMed Central

    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

  9. [Effect of eleutherococcus on hemostasis in immobilized rats].

    PubMed

    Shakhmatov, I I; Bondarchuk, Iu A; Vdovin, V M; Alekseeva, O V; Kiselev, V I

    2007-01-01

    The influence of a chronic (30 days) administration of an eleutherococcus extract on the haemostatic system state was studied in immobilized rats. A 3-h immobilization of untreated animals is accompanied by hypercoagulation and thrombinemia signs on the background of downregulation of the anticoagulant and fibrinolytic activity, which leads to a risk of thrombosis. Preliminary 30-day course of eleutherococcus uptake prevents the immobilization-induced thrombosis in rats.

  10. New device for interdental immobilization.

    PubMed

    Divis, B O

    1992-09-01

    The immobilization of a simple fractured jaw with arch bars is a time-consuming, laborious procedure. The alternative method of immobilization described here uses a precisely threaded, 22-gauge, malleable stainless steel wire and a threaded nylon nut. It affords the surgeon relative safety from accidental puncture trauma and makes the interdental immobilization a precise and speedy procedure.

  11. Preliminary studies of alfaxalone for intravenous immobilization of juvenile captive estuarine crocodiles (Crocodylus porosus) and Australian freshwater crocodiles (Crocodylus johnstoni) at optimal and selected sub-optimal thermal zones.

    PubMed

    Olsson, Annabelle; Phalen, David; Dart, Christina

    2013-09-01

    To investigate the character of immobilization given by alfaxalone in juvenile crocodiles at optimal and at suboptimal temperatures. Prospective, randomized partial crossover study. Twenty captive male estuarine (weight 0.6-2.5 kg) and five captive male freshwater crocodiles (weight 0.2-0.6 kg). Crocodiles were acclimatized for 24 hours at one of the following environmental temperatures; 32 °C, 27 °C, 22 °C or 17 °C, then received 3 mg kg(-1) intravenous (IV) alfaxalone into the dorsal occipital venous sinus. Duration and quality of immobilization was assessed and heart rate (HR) measured. On a separate occasion each crocodile was immobilized at one other environmental temperature. Alfaxalone, 3 mg kg(-1) IV, produced immobilization for 55 (range 15-100 minutes in estuarine, and 20 (range 20-25) minutes in freshwater crocodiles at 32 °C. There was no significant difference overall in immobilization times between temperatures, other than that, in estuarine crocodiles, duration was shorter at 32 °C than 22 °C. The character of immobilization was unpredictable, with animals recovering without warning, or having extended recoveries requiring assisted ventilation. Assisted ventilation was necessary mainly at the lower temperatures. Median HR in all temperature treatments decreased within 5 minutes post-injection, but the change in HR over the duration of immobilization was affected by the temperature, with a progressively smaller range of fall as temperature decreased. At 17 °C, two estuarine crocodiles appeared to re-immobilize after initial recovery, became severely bradycardiac and required ventilation and re-warming. Alfaxalone IV in small captive estuarine and freshwater crocodiles provides adequate induction of immobilization at various temperatures. However, the unpredictable results following induction mean it is unsuitable for field use and should be restricted to environments where intubation and ventilation are available, where

  12. Immobilizing Yarrowia lipolytica Lipase Lip2 via Improvement of Microspheres by Gelatin Modification.

    PubMed

    Xie, Rong; Cui, Caixia; Chen, Biqiang; Tan, Tianwei

    2015-10-01

    The purpose of this study was to investigate the feasibility of immobilizing Yarrowia lipolytica lipase lip2 on epoxy microspheres with or without gelatin modifications. The activity of lipase immobilized on gelatin-modified supports was twofold higher than those immobilized on native supports. There was no significant difference in the Michaelis-Menten constant (K M ) between the two immobilized lipases. However, lipase immobilized on gelatin modified supports showed an approximately fourfold higher V max than lipase immobilized on native supports. Lipase immobilization on the gelatin-modified support exhibited a significantly improved operational stability in an esterification system. After it was reused for a total of 35 batches, the ester conversion of lipase immobilized on gelatin-modified and native microspheres was 83 and 60 %, respectively. Furthermore, the immobilized lipase could be stored at 4 °C for 12 months without any loss of activity.

  13. C-Terminal-oriented Immobilization of Enzymes Using Sortase A-mediated Technique.

    PubMed

    Hata, Yuto; Matsumoto, Takuya; Tanaka, Tsutomu; Kondo, Akihiko

    2015-10-01

    In the present study, sortase A-mediated immobilization of enzymes was used for the preparation of immobilized enzymes. Thermobifida fusca YX β-glucosidase (BGL) or Streptococcus bovis 148 α-amylase (AmyA) were produced with C-terminal sortase A recognition sequences. The resulting fusion proteins were successfully immobilized on nanoparticle surfaces using sortase A. Some properties (activity, stability, and reusability) of the immobilized fusion proteins were evaluated. Both immobilized BGL and immobilized AmyA prepared by the sortase A-mediated technique retained their catalytic activity, exhibiting activities 3.0- or 1.5-fold (respectively) of those seen with the same enzymes immobilized by chemical crosslinking. Immobilized enzymes prepared by the sortase A-mediated technique did not undergo dramatic changes in stability compared with the respective free enzymes. Thus, the sortase A-mediated technique provides a promising method for immobilization of active, stable enzymes.

  14. Influence of zeolite PZC and pH on the immobilization of cytochrome c: a preliminary study regarding the preparation of new biomaterials.

    PubMed

    Tavolaro, Palmira; Tavolaro, Adalgisa; Martino, Guglielmo

    2009-04-01

    The adsorption of cytochrome c on to zeolite crystals and membranes with different chemical composition and structure was studied. The structure and texture of zeolite materials were identified by X-ray diffraction (XRD) and scanning electron microscopy (FESEM), while the variation of protein conformation was studied by Fourier transform infrared attenuated total reflectance (FTIR-ATR) analysis. In order to separate the influence of zeolite structures from the effect of composite membranes, a through analysis of the cytochrome c adsorption was performed on different crystals by varying several experimental parameters such as: pH value, protein amount, zeolite structures and chemical compositions. It is shown that the electrostatic type of interaction seems to be of the utmost importance to govern the immobilization, while the zeolite Brönsted acidity of the support is the subordinate parameter which differentiates the adsorption performances of different zeolite structures (that distinct for chemical composition of the framework).

  15. Bacillus thuringiensis HCB6 Amylase Immobilization by Chitosan Beads

    NASA Astrophysics Data System (ADS)

    Zusfahair; Ningsih, D. R.; Kartika, D.; Fatoni, A.; Zuliana, A. L.

    2017-02-01

    The purpose of this study was to optimize the amylase immobilization using a chitosan bead and to characterize immobilized amylase of Bacillus thuringiensis Bacteria HCB6. This study was started of amylase production, continued by immobilization optimization including ratio of chitosan:enzymes, enzyme-matrix contact time, substrate concentration, pH effect, incubation temperature effect, reaction time, and stability of immobilized enzyme. Amylase activity assay was dinitro salicylic (DNS) method. The results showed the optimum chitosan:enzyme ratio was 2.5: 1 (v/v), immobilization contact time of 18 hours and immobilization efficiency of 87.93%. Furthermore, immobilized amylase of B. thuringiensis HCB6 showed optimum substrate concentration of 1.5%, optimum pH of 6, optimum incubation temperature of 37 ° C, and the reaction time of 30 minutes. The Michaelis-Menten constant KM value for free and immobilized amylase were 5.30% and 1.33% respectively. Immobilized amylase can be used up to five times with the remaining activity of 43.3%.

  16. In vivo studies to elucidate the role of extracellular polymeric substances from Azotobacter in immobilization of heavy metals.

    PubMed

    Joshi, Prachi M; Juwarkar, Asha A

    2009-08-01

    The role of extracellular polymeric substances (EPS) produced by the heavy metal-resistant strain of Azotobacter spp. in restricting the uptake of cadmium (Cd) and chromium (Cr) by wheat plants cultivated in soils contaminated with the respective heavy metals has been demonstrated. A heavy metal-resistant strain of Azotobacter spp. was isolated and identified. Minimum inhibitory concentrations (MIC) of Cd2+ and CrO4(2-) were determined to be 20 and 10 mg L(-1), respectively. Under in vitro conditions, the EPS produced by the strain could bind 15.17 +/- 0.58 mg g(-1) of Cd2+ and 21.9 +/- 0.08 mg g(-1) of CrO4(2-). Fourier transform infrared spectra of the EPS revealed the presence of functional groups like carboxyl (-COOH) and hydroxyl (-OH), primarily involved in metal ion binding. Under pot culture experiments, the isolated strain of Azotobacter was added to the metal-contaminated soils in the form of free cells and immobilized cells. The total Azotobacter count and plant metal concentrations under different treatments showed a negative coefficient between the Azotobacter population and plant Cd (-0.496) and Cr (-0.455). Thus it could be inferred that Azotobacter spp. is involved in metal ion complexation either through EPS or through cell wall lipopolysaccharides (LPS).

  17. [Transformation of icariin by immobilized β-glucosidase and snailase].

    PubMed

    Peng, Jing; Ma, Yi-hua; Chen, Yan; Liu, Cong-Yan; Gao, Xia; Zhou, Jing

    2015-12-01

    This study was performed to prepare immobilized β-glucosidase and snailase, then optimize and compare the process conditions for conversion of icariin. Immobilized β-glucosidase and snailase were prepared using crosslink-embedding method. The best conditions of the preparation process were optimized by single factor analysis and the properties of immobilized β-glucosidase and snailase were investigated. The reaction conditions including temperature, pH, substrate ratio, substrate concentration, reaction time and reusing times of the conversion of icariin using immobilized β-glucosidase or snailase were optimized. Immobilized β-glucosidase and snailase exhibited better heat stabilities and could remain about 60% activity after storage at 4 degrees C for 4 weeks. The optimized conditions for the conversion of icariin were as follows, the temperature of 50 degrees C, pH of 5.0, enzyme and substrate ratio of 1 : 1, substrate concentration of 0.1 mg x mL(-1), reaction time of 6 h for β-glucosidase and 2 h for snailase, respectively. In 5 experiments, the average conversion ratio of immobilized β-glucosidase and snailase was 70.76% and 74.97%. The results suggest an effect of promoted stabilities, prolonged lifetimes in both β-glucosidase and snailase after immobilization. The immobilized β-glucosidase and snailase exhibited a higher conversion rate and reusability compared to the free β-glucosidase and snailase. Moreover, the conversion rate of immobilized snailase was higher than that of immobilized β-glucosidase. The process of icariin conversion using immobilized β-glucosidase and snailase was moderate and feasible, which suggests that immobilized enzymes may hold a promise for industrial usage.

  18. Industrial use of immobilized enzymes.

    PubMed

    DiCosimo, Robert; McAuliffe, Joseph; Poulose, Ayrookaran J; Bohlmann, Gregory

    2013-08-07

    Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization.

  19. Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

    NASA Astrophysics Data System (ADS)

    Medina, Marjorie B.

    1999-01-01

    Escherichia coli O157:H7 outbreaks were mostly due to consumption of undercooked contaminated beef which resulted in severe illness and several fatalities. Recalls of contaminated meat are costly for the meat industry. Our research attempts to understand the mechanisms of bacterial adhesion on animal carcass in order to eliminate or reduce pathogens in foods. We have reported the interactions of immobilized E. coli O157:H7 cells with extracellular matrix (ECM) components using a surface plasmon resonance biosensor (BIAcore). These studies showed that immobilized bacterial cells allowed the study of real-time binding interactions of bacterial surface with the ECM compounds, collagen I, laminin and fibronectin. Collagen I and laminin bound to the E. coli sensor surface with dissociation and association rates ranging from 106 to 109. Binding of collagen I and laminin mixture resulted in synergistic binding signals. An inhibition model was derived using collagen-laminin as the ligand which binds with E. coli sensor. A select group of naturally occurring food additives was evaluated by determining their effectivity in inhibiting the collagen-laminin binding to the bacterial sensor. Bound collagen-laminin was detached from the E. coli sensor surface with the aid of an organic acid. The biosensor results were verified with cell aggregation assays which were observed with optical and electron microscopes. These biosensor studies provided understanding of bacterial adhesion to connective tissue macromolecules. It also provided a model system for the rapid assessment of potential inhibitors that can be used in carcass treatment to inhibit or reduce bacterial contamination.

  20. Hand immobilization affects arm and shoulder postural control.

    PubMed

    Bolzoni, Francesco; Bruttini, Carlo; Esposti, Roberto; Cavallari, Paolo

    2012-07-01

    It is a common experience, immediately after the removal of a cast or a splint, to feel motor awkwardness, which is usually attributed to muscular and joint immobilization. However, the same feeling may also be perceived after a brief period of immobilization. We provide evidence that this last effect stems from changes in the cortical organization of the focal movement as well as in the associated anticipatory postural adjustments. Indeed, these two aspects of the motor act are strongly correlated, although scaled in different manners. In fact, they are both shaped in the primary motor cortex, they both undergo similar amplitude and latency modulation and, as we will show, they are both impaired by the immobilization of the lone prime mover. Neuromuscular effects of limb immobilization are well known; however, most papers focus on changes occurring in the pathways projecting to the prime mover, which acts on the immobilized joint. Conversely, this study investigates the effect of immobilization on anticipatory postural adjustments. Indeed, we show that 12 h of wrist and fingers immobilization effectively modify anticipatory postural adjustments of the elbow and the shoulder, that is, those joints not immobilized within the fixation chain. Accordingly, the motor impairment observed after short-term immobilization most likely stems from the unbalance between anticipatory postural adjustments and the focal movement.

  1. Enzymes immobilized in mesoporous silica: a physical-chemical perspective.

    PubMed

    Carlsson, Nils; Gustafsson, Hanna; Thörn, Christian; Olsson, Lisbeth; Holmberg, Krister; Åkerman, Björn

    2014-03-01

    Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity. Real-time monitoring of the immobilization process and techniques that demonstrate that the enzymes are located inside the pores is discussed by contrasting them to the common practice of indirectly measuring the depletion of the protein concentration or enzyme activity in the surrounding bulk phase. We propose that pore filling (pore volume fraction occupied by proteins) is the best standard for comparing the amount of immobilized enzymes at the molecular level, and present equations to calculate pore filling from the more commonly reported immobilized mass. Methods to detect changes in enzyme structure upon immobilization and to study the microenvironment inside the pores are discussed in detail. Combining the knowledge generated from these methodologies should aid in rationally designing biocatalyst based on enzymes immobilized in mesoporous materials.

  2. Matrix-Immobilized BMP-2 on Microcontact Printed Fibronectin as an in vitro Tool to Study BMP-Mediated Signaling and Cell Migration

    PubMed Central

    Hauff, Kristin; Zambarda, Chiara; Dietrich, Miriam; Halbig, Maria; Grab, Anna Luise; Medda, Rebecca; Cavalcanti-Adam, Elisabetta Ada

    2015-01-01

    During development, growth factors (GFs) such as bone morphogenetic proteins (BMPs) exert important functions in several tissues by regulating signaling for cell differentiation and migration. In vivo, the extracellular matrix (ECM) not only provides support for adherent cells, but also acts as reservoir of GFs. Several constituents of the ECM provide adhesive cues, which serve as binding sites for cell trans-membrane receptors, such as integrins. In conveying adhesion-mediated signaling to the intracellular compartment, integrins do not function alone but rather crosstalk and cooperate with other receptors, such as GF receptors. Here, we present a strategy for the immobilization of BMP-2 onto cellular fibronectin (cFN), a key protein of the ECM, to investigate GF-mediated signaling and migration. Following biotinylation, BMP-2 was linked to biotinylated cFN using NeutrAvidin as cross-linker. Characterization with quartz crystal microbalance with dissipation monitoring and enzyme-linked immunosorbent assay confirmed the efficient immobilization of BMP-2 on cFN over a period of 24 h. To validate the bioactivity of matrix-immobilized BMP-2 (iBMP-2), we investigated short- and long-term responses of C2C12 myoblasts, which are an established in vitro model for BMP-2 signaling, in comparison to soluble BMP-2 (sBMP-2) or in absence of GFs. Similarly to sBMP-2, iBMP-2 triggered Smad 1/5 phosphorylation and translocation of the complex to the nucleus, corresponding to the activation of BMP-mediated Smad-dependent pathway. Additionally, successful suppression of myotube formation was observed after 6 days in sBMP-2 and iBMP-2. We next implemented this approach in the fabrication of cFN micropatterned stripes by soft lithography. These stripes allowed cell-surface interaction only on the patterned cFN, since the surface in between was passivated, thus serving as platform for studies on directed cell migration. During a 10-h observation time, the migratory behavior

  3. Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

    2015-01-01

    Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

  4. Excess Weapons Plutonium Immobilization in Russia

    SciTech Connect

    Jardine, L.; Borisov, G.B.

    2000-04-15

    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&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&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 excellent

  5. Enzyme Immobilization: An Overview on Methods, Support Material, and Applications of Immobilized Enzymes.

    PubMed

    Sirisha, V L; Jain, Ankita; Jain, Amita

    2016-01-01

    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.

  6. Immobilized Cell Research

    DTIC Science & Technology

    1990-10-31

    beads, the plasmid is twice as stable as in cells In a process where immobilized cells produce material grown in continuous culture over 200...carrageenan) or chemically cross-linked, or- Penicillium chrysogenum than in washed freely suspended ganic polymer (Ca-alginate, polyacrylamide, and mycelium ...these materials are formed into the freely suspended cells stopped after 6 days. If the beads of several millimeters in diameter by allowing the

  7. L-DOPA production by immobilized tyrosinase.

    PubMed

    Carvalho, G M; Alves, T L; Freire, D M

    2000-01-01

    The production of L-DOPA using L-tyrosine as substrate, the enzyme tyrosinase (EC 1.14.18.1) as biocatalyst, and L-ascorbate as reducing agent for the o-quinones produced by the enzymatic oxidation of the substrates was studied. Tyrosinase immobilization was investigated on different supports and chemical agents: chitin flakes activated with hexamethylenediamine and glutaraldehyde as crosslinking agent, chitosan gel beads, chitosan gel beads in the presence of glutaraldehyde, chitosan gel beads in the presence of polyvinylpyrrolidone, and chitosan flakes using glutaraldehyde as crosslinking agent. The last support was considered the best using as performance indexes the following set of immobilization parameters: efficiency (90.52%), yield (11.65%), retention (12.87%), and instability factor (0.00). The conditions of immobilization on chitosan flakes were optimized using a two-level full factorial experimental design. The independent variables were enzyme-support contact time (t), glutaraldehyde concentration (G), and the amount of enzyme units initially offered (UC). The response variable was the total units of enzymatic activity shown by the immobilized enzyme (UIMO). The optimal conditions were t = 24 h, G = 2% (v/v), and UC = 163.7 U. Under these conditions the total units of enzymatic activity shown by the immobilized enzyme (UIMO) was 23.3 U and the rate of L-DOPA production rate was 53.97 mg/(L.h).

  8. The influence of carbon nanotubes on enzyme activity and structure: investigation of different immobilization procedures through enzyme kinetics and circular dichroism studies.

    PubMed

    Cang-Rong, Jason Teng; Pastorin, Giorgia

    2009-06-24

    In the last decade, many environmental organizations have devoted their efforts to identifying renewable biosystems, which could provide sustainable fuels and thus enhance energy security. Amidst the myriad of possibilities, some biofuels make use of different types of waste biomasses, and enzymes are often employed to hydrolyze these biomasses and produce sugars that will be subsequently converted into ethanol. In this project, we aimed to bridge nanotechnology and biofuel production: here we report on the activity and structure of the enzyme amyloglucosidase (AMG), physically adsorbed or covalently immobilized onto single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs). In fact, carbon nanotubes (CNTs) present several properties that render them ideal support systems, without the diffusion limitations displayed by porous material and with the advantage of being further functionalizable at their surface. Chemical ligation was achieved both on oxidized nanotubes (via carbodiimide chemistry), as well as on amino-functionalized nanotubes (via periodate-oxidized AMG). Results showed that AMG retained a certain percentage of its specific activity for all enzyme-carbon nanotubes complexes prepared, with the physically adsorbed samples displaying better catalytic efficiency than the covalently immobilized samples. Analysis of the enzyme's structure through circular dichroism (CD) spectroscopy revealed significant structural changes in all samples, the degree of change being consistent with the activity profiles. This study proves that AMG interacts differently with carbon nanotubes depending on the method employed. Due to the higher activity reported by the enzyme physically adsorbed onto CNTs, these samples demonstrated a vast potential for further development. At the same time, the possibility of inducing magnetic properties into CNTs offers the opportunity to easily separate them from the original solution. Hence, substances to which they

  9. The influence of carbon nanotubes on enzyme activity and structure: investigation of different immobilization procedures through enzyme kinetics and circular dichroism studies

    NASA Astrophysics Data System (ADS)

    Cang-Rong, Jason Teng; Pastorin, Giorgia

    2009-06-01

    In the last decade, many environmental organizations have devoted their efforts to identifying renewable biosystems, which could provide sustainable fuels and thus enhance energy security. Amidst the myriad of possibilities, some biofuels make use of different types of waste biomasses, and enzymes are often employed to hydrolyze these biomasses and produce sugars that will be subsequently converted into ethanol. In this project, we aimed to bridge nanotechnology and biofuel production: here we report on the activity and structure of the enzyme amyloglucosidase (AMG), physically adsorbed or covalently immobilized onto single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs). In fact, carbon nanotubes (CNTs) present several properties that render them ideal support systems, without the diffusion limitations displayed by porous material and with the advantage of being further functionalizable at their surface. Chemical ligation was achieved both on oxidized nanotubes (via carbodiimide chemistry), as well as on amino-functionalized nanotubes (via periodate-oxidized AMG). Results showed that AMG retained a certain percentage of its specific activity for all enzyme-carbon nanotubes complexes prepared, with the physically adsorbed samples displaying better catalytic efficiency than the covalently immobilized samples. Analysis of the enzyme's structure through circular dichroism (CD) spectroscopy revealed significant structural changes in all samples, the degree of change being consistent with the activity profiles. This study proves that AMG interacts differently with carbon nanotubes depending on the method employed. Due to the higher activity reported by the enzyme physically adsorbed onto CNTs, these samples demonstrated a vast potential for further development. At the same time, the possibility of inducing magnetic properties into CNTs offers the opportunity to easily separate them from the original solution. Hence, substances to which they

  10. Study on stability mechanism of immobilized pH gradient in isoelectric focusing via the Svensson-Tiselius differential equation and moving reaction boundary.

    PubMed

    Guo, Chen-Gang; Li, Si; Wang, Hou-Yu; Zhang, Dong; Li, Guo-Qing; Zhang, Jie; Fan, Liu-Yin; Cao, Cheng-Xi

    2013-07-15

    An immobilized pH gradient (IPG) has strong power against instability (e.g., drifting and plateau) existing in classic isoelectric focusing (IEF). However, the relevant mechanism against the instability of pH gradient is still unclear. In this work, the theories of diffusional current and water products in IEF were developed based on the Svensson-Tiselius's differential equation and concept of moving reaction boundary (MRB). Two novel methods of pH gradient mobilization in IPG-IEF and non-IPG-IEF (opposite to IPG-IEF) were developed to unveil stability mechanism of IPG-IEF. The theoretical and experimental results indicated that (i) the drifting of pH gradient in non-IPG-IEF could be effectively controlled by IPG technique due to the existence of equal-fluxes of hydroxyl and hydrogen ions in the IPG-IEF system, (ii) there existed high diffusional current in non-IPG-IEF because of the existence of free carrier ampholyte (CA), but weak current in the IPG-IEF due to the immobilization of CA species in gel matrix, and (iii) the high diffusional current resulted in a great amount of water formation in neutral zone of pH gradient that led to distinct plateau in non-IPG-IEF, conversely the weak diffusional current caused little of water formation and weak plateau of pH gradient in IPG-IEF. These studies have considerable significance to the understanding of mechanism and development of protein IEF separation technique.

  11. A phantom study of the immobilization and the indications for using virtual isocenter in stereoscopic X-ray image guidance system referring to position localizer in frameless radiosurgery.

    PubMed

    Chang, Hsiao-Han; Lee, Hsiao-Fei; Sung, Chien-Cheng; Liao, Tsung-I; Huang, Yu-Jie

    2013-07-08

    A frameless radiosurgery system is using a set of thermoplastic mask for fixation and stereoscopic X-ray imaging for alignment. The accuracy depends on mask fixation and imaging. Under certain circumstances, the guidance images may contain insufficient bony structures, resulting in lesser accuracy. A virtual isocenter function is designed for such scenarios. In this study, we investigated the immobilization and the indications for using virtual isocenter. Twenty-four arbitrary imaginary treatment targets (ITTs) in phantom were evaluated. The external Localizer with positioner films was used as reference. The alignments by using actual and virtual isocenter in image guidance were compared. The deviation of the alignment after mask removing and then resetting was also checked. The results illustrated that the mean deviation between the alignment by image guidance using actual isocenter (Iso(img)) and the localizer(Iso(loc)) was 2.26 mm ± 1.16 mm (standard deviation, SD), 1.66 mm ± 0.83 mm for using virtual isocenter. The deviation of the alignment by the image guidance using actual isocenter to the localizer before and after mask resetting was 7.02 mm ± 5.8 mm. The deviations before and after mask resetting were insignificant for the target center from skull edge larger than 80 mm on craniocaudal direction. The deviations between the alignment using actual and virtual isocenter in image guidance were not significant if the minimum distance from target center to skull edge was larger or equal to 30 mm. Due to an unacceptable deviation after mask resetting, the image guidance is necessary to improve the accuracy of frameless immobilization. A treatment isocenter less than 30 mm from the skull bone should be an indication for using virtual isocenter to align in image guidance. The virtual isocenter should be set as caudally as possible, and the sella of skull should be the ideal point.

  12. Isomaltulose production using immobilized cells.

    PubMed

    Chhetham, P S; Garrett, C; Clark, J

    1985-04-01

    Three strains of Erwinia rhapontici especially suitable for use in the form of nongrowing immobilized cells were selected by screening strains of cells for high activity and operational stability in an immobilized form. Immobilization in calcium alginate gel pellets was easily the best method of immobilizing E. rhapontici. Much greater operational stabilities were obtained than when other immobilization methods were used. Conditions of operation which optimize the activity, stability, and yield and the ease of operation of the immobilized cell columns working in a steady state are described. These include the effects of substrate concentration, diffusional restrictions and water activity, the concentration of cells immobilized, and the type of reactor used. Thus, the immobilized cells produce about 1500 times their own weight of isomaltulose during one half-life of use (ca. 1 year). Loss of activity was most closely correlated with the volume of substrate processed and so presumably is due to the presence of low concentrations of a cummulative inhibitor in the substrate. Methods for regenerating the activity of the immobilized cells by the periodic administration of nutrients, of forming isomaltulose by continuously supplying nutrients to growing immobilized cells, and of crystallizing isomaltulose from the column eluate are also described.

  13. Evaluation of two-dimensional bolus effect of immobilization/support devices on skin doses: A radiochromic EBT film dosimetry study in phantom

    SciTech Connect

    Chiu-Tsao, Sou-Tung; Chan, Maria F.

    2010-07-15

    Purpose: In this study, the authors have quantified the two-dimensional (2D) perspective of skin dose increase using EBT film dosimetry in phantom in the presence of patient immobilization devices during conventional and IMRT treatments. Methods: For 6 MV conventional photon field, the authors evaluated and quantified the 2D bolus effect on skin doses for six different common patient immobilization/support devices, including carbon fiber grid with Mylar sheet, Orfit carbon fiber base plate, balsa wood board, Styrofoam, perforated AquaPlast sheet, and alpha-cradle. For 6 and 15 MV IMRT fields, a stack of two film layers positioned above a solid phantom was exposed at the air interface or in the presence of a patient alpha-cradle. All the films were scanned and the pixel values were converted to doses based on an established calibration curve. The authors determined the 2D skin dose distributions, isodose curves, and cross-sectional profiles at the surface layers with or without the immobilization/support device. The authors also generated and compared the dose area histograms (DAHs) and dose area products from the 2D skin dose distributions. Results: In contrast with 20% relative dose [(RD) dose relative to d{sub max} on central axis] at 0.0153 cm in the film layer for 6 MV 10x10 cm{sup 2} open field, the average RDs at the same depth in the film layer were 71%, 69%, 55%, and 57% for Orfit, balsa wood, Styrofoam, and alpha-cradle, respectively. At the same depth, the RDs were 54% under a strut and 26% between neighboring struts of a carbon fiber grid with Mylar sheet, and between 34% and 56% for stretched perforated AquaPlast sheet. In the presence of the alpha-cradle for the 6 MV (15 MV) IMRT fields, the hot spot doses at the effective measurement depths of 0.0153 and 0.0459 cm were 140% and 150% (83% and 89%), respectively, of the isocenter dose. The enhancement factor was defined as the ratio of a given DAH parameter (minimum dose received in a given area) with

  14. Immobilization of peroxidase on SPEU film via radiation grafting

    NASA Astrophysics Data System (ADS)

    Hongfei, Ha; Guanghui, Wang; Jilan, Wu

    The acrylic acid or acrylamide were grafted via radiation onto segmented polyetherurethane (SPEU) film which is a kind of biocompatible material. Then the Horse radish peroxidase was immobilized on the grafted SPEU film through chemical binding. Some quantitative relationships between the percent graft and the activity, amount of immobilized enzyme were given. The properties and application of obtained biomaterial was studied as well.

  15. Effects of immobilization on spermiogenesis

    NASA Technical Reports Server (NTRS)

    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.

  16. Uranium immobilization and nuclear waste

    SciTech Connect

    Duffy, C.J.; Ogard, A.E.

    1982-02-01

    Considerable information useful in nuclear waste storage can be gained by studying the conditions of uranium ore deposit formation. Further information can be gained by comparing the chemistry of uranium to nuclear fission products and other radionuclides of concern to nuclear waste disposal. Redox state appears to be the most important variable in controlling uranium solubility, especially at near neutral pH, which is characteristic of most ground water. This is probably also true of neptunium, plutonium, and technetium. Further, redox conditions that immobilize uranium should immobilize these elements. The mechanisms that have produced uranium ore bodies in the Earth's crust are somewhat less clear. At the temperatures of hydrothermal uranium deposits, equilibrium models are probably adequate, aqueous uranium (VI) being reduced and precipitated by interaction with ferrous-iron-bearing oxides and silicates. In lower temperature roll-type uranium deposits, overall equilibrium may not have been achieved. The involvement of sulfate-reducing bacteria in ore-body formation has been postulated, but is uncertain. Reduced sulfur species do, however, appear to be involved in much of the low temperature uranium precipitation. Assessment of the possibility of uranium transport in natural ground water is complicated because the system is generally not in overall equilibrium. For this reason, Eh measurements are of limited value. If a ground water is to be capable of reducing uranium, it must contain ions capable of reducing uranium both thermodynamically and kinetically. At present, the best candidates are reduced sulfur species.

  17. [Immobilization of penicilin G acylase on polyacrylonitrile fiber].

    PubMed

    Xian, H; Wang, Z

    2001-08-01

    The immobilization of Penicillin G Acylase from Bacillus megaterium by glutaraldehyde crosslinking on the partially acid-hydrolyed polyacrylonitrile fiber was studied. When the amount of--NH2 on fiber were 690 mumol/g and the moisture in the fiber was 64%, and the content of enzyme protein immobilized on fiber was more than 100 mg/g. The activity of 2300 IU/g was obtained with 30% of overall yield and 56% of binding efficiency. The immobilization yield was markedly influenced by ratio of the amount of free enzyme used to the weight of the fiber. The half-life of storage stability of immobilized PGA at room temperature was 130 days. The immobilized PGA kept 80% of the initial activity after 20 cycles of operation in 10% of PGK(W/V) in 0.05 mol/L phosphate buffer, pH 8.0, at 37 degrees C and an enzyme load of 150 IU/g(PGK) and 10 g(PGK) for per cycle of operation. The hydrolysis conversion of PGK in the range of 2.5%-12.5% (W/V) were over 98% for the immobilized PGA. The operation stability of immobilized PGA treated with DTT was better than that of immobilized PGA untreated.

  18. IN SITU LEAD IMMOBILIZATION BY APATITE

    EPA Science Inventory

    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...

  19. IN SITU LEAD IMMOBILIZATION BY APATITE

    EPA Science Inventory

    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...

  20. Use of reversible denaturation for adsorptive immobilization of urease.

    PubMed

    Azari, F; Hosseinkhani, S; Nemat-Gorgani, M

    2001-06-01

    Urease was chosen as a model multimeric protein to investigate the utility of reversible denaturation for immobilization to a hydrophobic support. Of the various procedures investigated, acidic denaturation provided the highest degree of immobilization and enzymatic activity with lowering of Km (apparent). Exposure of hydrophobic clusters in the protein molecule induced by the acidic pH environment was confirmed by fluorescence studies using 8-anilino-1-naphtalene-sulfonate as a hydrophobic-reporter probe. The catalytic potential of the enzyme at low pH values was dramatically improved with significant heat and pH stability enhancement on immobilization. Furthermore, the immobilized preparation was used successfully in continuous catalytic transformations. Based on the results presented in this article and a recent report involving a relatively more simple monomeric protein, it is suggested that reversible denaturation may be of general utility for immobilization of proteins, which are not normally adsorbed on hydrophobic supports.

  1. Metabolic alkalosis during immobilization in monkeys (M. nemestrina)

    NASA Technical Reports Server (NTRS)

    Young, D. R.; Yeh, I.; Swenson, R. S.

    1983-01-01

    The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.

  2. Metabolic alkalosis during immobilization in monkeys (M. nemestrina)

    NASA Technical Reports Server (NTRS)

    Young, D. R.; Yeh, I.; Swenson, R. S.

    1983-01-01

    The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.

  3. The biosorption capacity of biochar for 4-bromodiphengl ether: study of its kinetics, mechanism, and use as a carrier for immobilized bacteria.

    PubMed

    Du, Jingting; Sun, Pengfei; Feng, Zhuo; Zhang, Xin; Zhao, Yuhua

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) are known as ubiquitous pollutants in ecological systems and thus pose a great threat to the health of humans and other organisms due to their bioamplification and bioaccumulation along the food chain. The present study was designed to investigate the biosorption capacity of biochar for the removal of 4-monobromodiphengl ether and its synergistic effect when used as a carrier to immobilize the 4-monobromodiphengl ether-degrading strain Sphingomonas sp. DZ3. The raw biochar material was prepared by pyrolyzing maize straw at 350 °C under oxygen-limited conditions. The maximum biosorption capacity of biochar for 4-bromodiphengl ether was determined to be 50.23 mg/L under an initial concentration of 800 mg/L at pH 7.0 and 40 °C. The data obtained from the biosorption studies were fitted successfully with the pseudo-first-order kinetic and Freundlich isotherm models. The Weber-Morris model analysis indicated that intraparticle diffusion was the limiting step in the biosorption of 4-bromodiphengl ether onto the biosorbent. The values of thermodynamic parameters △G0 were calculated as -24.61 kJ/mol (20 °C), -24.35 kJ/mol (30 °C), and -23.98 kJ/mol (40 °C), △S(0) was -8.45 kJ/mol/K, and △H(0) was 21.36 kJ/mol. The artificial neural network analysis indicated that the initial concentration appeared to be the most influential parameter on the biosorption processes. The removal rate of 4-bromodiphengl ether achieved using the biochar-microorganism system was increased by 63 and 83% compared with the rates obtained with biochar and the strain individually, respectively. The morphology of the biochar and immobilized strain was determined using a scanning electron microscope, and information of the surface functional groups of biochar was obtained through an infrared spectra study.

  4. [Covalent immobilization of glucose oxidase within organic media].

    PubMed

    Zhou, Tao; Zhu, Xiongjun; Su, Jianhua; Yao, Dongsheng; Liu, Daling

    2012-04-01

    Activity losing during the covalent immobilization of enzyme is a serious problem. Here we studied organic phase immobilization by using glucose oxidase (GOD) as a model. After lyophilized at optimum pH, GOD is covalently immobilized onto glutaraldhyde-activated chitosan microsphere carrier under the condition of water, 1, 4-dioxane, ether and ethanol separately. The special activities, enzyme characterization and kinetic parameters are determined. Results show that all of the organic phase immobilized GODs have higher special activities and larger K(cat) than that of aqueous phase. Under the conditions of 0.1% of glutaraldehyde, 1.6% moisture content with 80 mg of GOD added to per gram of carrier, 2.9-fold of the special activity and 3-fold of the effective activity recovery ratio were obtained, and 3-fold of the residue activity was demonstrated after 7 runs when compares 1, 4-dioxane phase immobilized GOD with water phase immobilized one. In addition, kinetic study shows that 1,4-dioxane immobilized GOD (Km(app) = 5.63 mmol/L, V(max) = 1.70 micromol/(min x mg GOD), K(cat) = 0.304 s(-1) was superior to water immobilized GOD (Km(app) = 7.33 mmol/L, V(max) = 1.02 micromol/(min x mg GOD), K(cat) = 0.221 s(-1)). All above indicated GOD immobilized in proper organic media presented a better activity with improved catalytic performance. Organic phase immobilization might be one of the ways to overcome the conformational denature of enzyme protein during covalent modification.

  5. Characterization and study of the orientation of immobilized enzymes by tryptic digestion and HPLC-MS: design of an efficient catalyst for the synthesis of cephalosporins.

    PubMed

    Temporini, Caterina; Bonomi, Paolo; Serra, Immacolata; Tagliani, Auro; Bavaro, Teodora; Ubiali, Daniela; Massolini, Gabriella; Terreni, Marco

    2010-06-14

    An innovative approach to determine the orientation of penicillin G acylase (PGA) from Escherichia coli covalently immobilized onto solid supports has been developed. This method is based on tryptic digestion of immobilized PGA followed by HPLC-MS analysis of the released peptides which are supposed to be only those exposed toward the reaction medium and not directly bound to the solid support. To this purpose, PGA was immobilized on Eupergit C (acrylic hydrophobic resin) and glyoxyl-agarose (hydrophilic resin) functionalized with epoxy and aldehyde groups, respectively, both involving the Lys residues of the protein. The peptide maps obtained were analyzed to derive the orientation of immobilized PGA, as the position of the detected Lys gave indication concerning the accessibility of the different areas of the protein. The results indicate that PGA immobilization on both supports involves mainly Lys located near the binding pocket (70%). Some differences in the enzyme orientation on the two supports can be deduced by the presence of different unbound Lys residues in the released peptides, specific to each support (Lys 117alpha for PGA-Eupergit C; Lys 163alpha and Lys 165alpha for PGA-glyoxyl-agarose). These results have been correlated with the data obtained in the kinetically controlled synthesis and indicate that the orientation of PGA on both supports is partially unfavorable, driving the active site near the support surface. This type of orientation of the enzyme enhances the effect of the nature of the support and of the binding chemistry on the catalytic properties. The information obtained indicated the most suitable support and activation strategy to design an immobilized acylase with good synthetic properties for preparative processes. The glyoxyl-Eupergit C support with enhanced porosity synergically combines the mechanical stability and synthetic performances of immobilized PGA and was successfully used in the synthesis of several cephalosporins.

  6. Effect of low molecular weight additives on immobilization strength, activity, and conformation of protein immobilized on PVC and UHMWPE.

    PubMed

    Kondyurin, Alexey; Nosworthy, Neil J; Bilek, Marcela M M

    2011-05-17

    Horseradish peroxidase (HRP) was immobilized onto both plasticized and unplasticized polyvinylchloride (PVC) and ultrahigh molecular weight polyethylene (UHMWPE). Plasma immersion ion implantation (PIII) in a nitrogen plasma with 20 kV bias was used to facilitate covalent immobilization and to improve the wettability of the surfaces. The surfaces and immobilized protein were studied using attenuated total reflection infrared (ATR-IR) spectroscopy and water contact angle measurements. Protein elution on exposure to repeated sodium dodecyl sulfate (SDS) washing was used to assess the strength of HRP immobilization. The presence of low molecular weight components (plasticizer, additives in solvent, unreacted monomers, adsorbed molecules on surface) was found to have a major influence on the strength of immobilization and the conformation of the protein on the samples not exposed to the PIII treatment. A phenomenological model considering interactions between the low molecular weight components, the protein molecule, and the surface is developed to explain these observations.

  7. [Immobilized microorganisms and water purification].

    PubMed

    Mogilevich, N F

    1995-01-01

    Advantages and disadvantages of cells of aerobic microorganisms immobilized by the type of adhesion and incorporation into the gel beads, the amount of retained biomass, limitations of diffusion of oxygen and nutrients, viability, morphology, biochemical properties are described. Immobilized biocatalysts are discussed in the aspect of their use in purification of sewage waters.

  8. Immobilization of horseradish peroxidase onto kaolin.

    PubMed

    Šekuljica, Nataša Ž; Prlainović, Nevena Ž; Jovanović, Jelena R; Stefanović, Andrea B; Djokić, Veljko R; Mijin, Dušan Ž; Knežević-Jugović, Zorica D

    2016-03-01

    Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-Emmett-Teller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 °C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 ± 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes.

  9. Electron Tomography of Cryo-Immobilized Plant Tissue: A Novel Approach to Studying 3D Macromolecular Architecture of Mature Plant Cell Walls In Situ

    PubMed Central

    Sarkar, Purbasha; Bosneaga, Elena; Yap, Edgar G.; Das, Jyotirmoy; Tsai, Wen-Ting; Cabal, Angelo; Neuhaus, Erica; Maji, Dolonchampa; Kumar, Shailabh; Joo, Michael; Yakovlev, Sergey; Csencsits, Roseann; Yu, Zeyun; Bajaj, Chandrajit; Downing, Kenneth H.; Auer, Manfred

    2014-01-01

    Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the

  10. Electron tomography of cryo-immobilized plant tissue: a novel approach to studying 3D macromolecular architecture of mature plant cell walls in situ.

    PubMed

    Sarkar, Purbasha; Bosneaga, Elena; Yap, Edgar G; Das, Jyotirmoy; Tsai, Wen-Ting; Cabal, Angelo; Neuhaus, Erica; Maji, Dolonchampa; Kumar, Shailabh; Joo, Michael; Yakovlev, Sergey; Csencsits, Roseann; Yu, Zeyun; Bajaj, Chandrajit; Downing, Kenneth H; Auer, Manfred

    2014-01-01

    Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼ 2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the

  11. Continuous administration of pyridostigmine improves immobilization-induced neuromuscular weakness.

    PubMed

    Frick, Christiane G; Helming, Marc; Martyn, J A Jeevendra; Blobner, Manfred; Fink, Heidrun

    2010-03-01

    To investigate the effects of continuous pyridostigmine infusion on immobilization-induced muscle weakness. Critical illness often results in immobilization of limb and respiratory muscles, leading to muscle atrophy and up-regulation of nicotinic acetylcholine receptors. Pyridostigmine reversibly blocks acetylcholinesterase and has the potential to improve neuromuscular transmission and decrease acetylcholine receptor number. Prospective, randomized, controlled experimental study. Animal laboratory, university hospital. Male Sprague-Dawley rats. A total of 40 rats were immobilized in one hind limb by pinning knee and ankle joints. Rats received either continuous pyridostigmine (15 mg.kg.day) or saline subcutaneously via implanted osmotic pumps. After 7 days and 14 days of immobilization, neuromuscular function, atracurium pharmacodynamics, and expression of acetylcholine receptors were evaluated. At 7 days and 14 days after immobilization, muscle force decreased in all untreated groups, whereas effective doses for paralysis with atracurium and acetylcholine receptor number in the tibialis were significantly increased. Pyridostigmine-treated rats showed a significantly improved muscle force and muscle mass in the immobilized limb. This was associated with an attenuation of acetylcholine receptor up-regulation in the respective leg. At this time, the dose-response curve for atracurium on the immobilized side was shifted to the left in the pyridostigmine group. After 14 days, muscle tension was still less depressed with pyridostigmine infusion, and resistance to the effects of atracurium was still attenuated. However, there were no differences in acetylcholine receptor expression between the immobilized sides of both groups. Continuous pyridostigmine infusion improves muscle weakness after 7 days and 14 days of immobilization. The up-regulation of acetylcholine receptors and the concomitant resistance to atracurium is attenuated in animals treated with pyridostigmine

  12. Potential immobilized Saccharomyces cerevisiae as heavy metal removal

    NASA Astrophysics Data System (ADS)

    Raffar, Nur Izzati Abdul; Rahman, Nadhratul Nur Ain Abdul; Alrozi, Rasyidah; Senusi, Faraziehan; Chang, Siu Hua

    2015-05-01

    Biosorption of copper ion using treated and untreated immobilized Saccharomyces cerevisiae from aqueous solution was investigate in this study. S.cerevisiae has been choosing as biosorbent due to low cost, easy and continuously available from various industries. In this study, the ability of treated and untreated immobilized S.cerevisiae in removing copper ion influence by the effect of pH solution, and initial concentration of copper ion with contact time. Besides, adsorption isotherm and kinetic model also studied. The result indicated that the copper ion uptake on treated and untreated immobilized S.cerevisiae was increased with increasing of contact time and initial concentration of copper ion. The optimum pH for copper ion uptake on untreated and treated immobilized S.cerevisiae at 4 and 6. From the data obtained of copper ion uptake, the adsorption isotherm was fitted well by Freundlich model for treated immobilized S.cerevisiae and Langmuir model for untreated immobilized S.cerevisiae according to high correlation coefficient. Meanwhile, the pseudo second order was described as suitable model present according to high correlation coefficient. Since the application of biosorption process has been received more attention from numerous researchers as a potential process to be applied in the industry, future study will be conducted to investigate the potential of immobilized S.cerevisiae in continuous process.

  13. Highly sensitive detection of influenza virus in saliva by real-time PCR method using sugar chain-immobilized gold nanoparticles; application to clinical studies.

    PubMed

    Suda, Yasuo; Nagatomo, Mami; Yokoyama, Risa; Ohzono, Mami; Aoyama, Kazue; Zhang, Xu; Nakajima, Kazuhiko; Murakami, Naoki; Shinoda, Tadashi; Hirota, Tatsuhiko; Yanagihara, Sae; Nishi, Jun-Ichiro

    2015-09-01

    A highly sensitive and convenient method for detecting influenza virus was developed using modified end-point melt curve analysis of a RT-qPCR SYBR Green method and influenza virus-binding sugar chain-immobilized gold-nanoparticles (SGNP). Because SGNPs capture influenza viruses, the virus-SGNP complex was separated easily by centrifugation. Viral RNA was detected at very low concentrations, suggesting that SGNP increased sensitivity compared with standard methods. This method was applied to clinical studies. Influenza viruses were detected in saliva of patients or inpatients who had been considered influenza-free by a rapid diagnostic assay of nasal swabs. Furthermore, the method was applied to a human trial of prophylactic anti-influenza properties of yogurt containing Lactobacillus acidophilus L-92. The incidence of influenza viruses in saliva of the L-92 group was found to be significantly lower compared to the control group. Thus, this method was useful for monitoring the course of anti-influenza treatment or preventive measures against nosocomial infection.

  14. Immobilization of Pb, Cd, and Zn in a contaminated soil using eggshell and banana stem amendments: metal leachability and a sequential extraction study.

    PubMed

    Ashrafi, Mehrnaz; Mohamad, Sharifah; Yusoff, Ismail; Shahul Hamid, Fauziah

    2015-01-01

    Heavy-metal-contaminated soil is one of the major environmental pollution issues all over the world. In this study, two low-cost amendments, inorganic eggshell and organic banana stem, were applied to slightly alkaline soil for the purpose of in situ immobilization of Pb, Cd, and Zn. The artificially metal-contaminated soil was treated with 5% eggshell or 10% banana stem. To simulate the rainfall conditions, a metal leaching experiment for a period of 12 weeks was designed, and the total concentrations of the metals in the leachates were determined every 2 weeks. The results from the metal leaching analysis revealed that eggshell amendment generally reduced the concentrations of Pb, Cd, and Zn in the leachates, whereas banana stem amendment was effective only on the reduction of Cd concentration in the leachates. A sequential extraction analysis was carried out at the end of the experiment to find out the speciation of the heavy metals in the amended soils. Eggshell amendment notably decreased mobility of Pb, Cd, and Zn in the soil by transforming their readily available forms to less accessible fractions. Banana stem amendment also reduced exchangeable form of Cd and increased its residual form in the soil.

  15. Plutonium Immobilization Canister Loading

    SciTech Connect

    Hamilton, E.L.

    1999-01-26

    This disposition of excess plutonium is determined by the Surplus Plutonium Disposition Environmental Impact Statement (SPD-EIS) being prepared by the Department of Energy. The disposition method (Known as ''can in canister'') combines cans of immobilized plutonium-ceramic disks (pucks) with vitrified high-level waste produced at the SRS Defense Waste Processing Facility (DWPF). This is intended to deter proliferation by making the plutonium unattractive for recovery or theft. The envisioned process remotely installs cans containing plutonium-ceramic pucks into storage magazines. Magazines are then remotely loaded into the DWPF canister through the canister neck with a robotic arm and locked into a storage rack inside the canister, which holds seven magazines. Finally, the canister is processed through DWPF and filled with high-level waste glass, thereby surrounding the product cans. This paper covers magazine and rack development and canister loading concepts.

  16. Two-dimensional (2D) infrared correlation study of the structural characterization of a surface immobilized polypeptide film stimulated by pH

    NASA Astrophysics Data System (ADS)

    Chae, Boknam; Son, Seok Ho; Kwak, Young Jun; Jung, Young Mee; Lee, Seung Woo

    2016-11-01

    The pH-induced structural changes to surface immobilized poly (L-glutamic acid) (PLGA) films were examined by Fourier transform infrared (FTIR) spectroscopy and two-dimensional (2D) correlation analysis. Significant spectral changes were observed in the FTIR spectra of the surface immobilized PLGA film between pH 6 and 7. The 2D correlation spectra constructed from the pH-dependent FTIR spectra of the surface immobilized PLGA films revealed the spectral changes induced by the alternations of the protonation state of the carboxylic acid group in the PLGA side chain. When the pH was increased from 6 to 8, weak spectral changes in the secondary structure of the PLGA main chain were induced by deprotonation of the carboxylic acid side group.

  17. Status of immobilization of excess weapons plutonium in Russia

    SciTech Connect

    Borisov, G B; Jardine, L; Mansourov, O A

    1999-02-03

    In this paper, we examine the logic and framework for the development of a capability to immobilize excess Russian weapons plutonium by the year 2004. The initial activities underway in Russia, summarized here, include engineering feasibility studies of the immobilization of plutonium-containing materials at the Krasnoyarsk and Mayak industrial sites. In addition, research and development (R&D) studies are underway at Russian institutes to develop glass and ceramic forms suitable for the immobilization of plutonium-containing materials, residues, and wastes and for their geologic disposal.

  18. Advances in ethanol production using immobilized cell systems

    SciTech Connect

    Margaritis, A.; Merchant, F.J.A.

    1984-01-01

    The application of immobilized cell systems for the production of ethanol has resulted in substantial improvements in the efficiency of the process when compared to the traditional free cell system. In this review, the various methods of cell immobilization employed in ethanol production systems have been described in detail. Their salient features, performance characteristics, advantages and limitations have been critically assessed. More recently, these immobilized cell systems have also been employed for the production of ethanol from non-conventional feedstocks such as Jerusalem artichoke extracts, cheese whey, cellulose, cellobiose and xylose. Ethanol production by immobilized yeast and bacterial cells has been attempted in various bioreactor types. Although most of these studies have been carried out using laboratory scale prototype bioreactors, it appears that only fluidized bed, horizontally packed bed bioreactors and tower fermenters may find application on scale-up. Several studies have indicated that upon immobilization, yeast cells performing ethanol fermentation exhibit more favourable physiological and metabolic properties. This, in addition to substantial improvements in ethanol productivities by immobilized cell systems, is indicative of the fact that future developments in the production of ethanol and alcoholic beverages will be directed towards the use of immobilized cell systems. 291 references.

  19. Influence of ROM Exercise on the Joint Components during Immobilization.

    PubMed

    Matsuzaki, Taro; Yoshida, Shinya; Kojima, Satoshi; Watanabe, Masanori; Hoso, Masahiro

    2013-12-01

    [Purpose] The aim of this study was to clarify the effects of the ROM exercise on joint components according to histopathological analysis. [Subjects and Methods] In total, twenty-six 9-week-old adult male Wistar rats were used in this study. The rats were randomly divided into three groups, the immobilization group (n=10), exercise group (n=10), and control group (n=6). The immobilization group and exercise group were anaesthetized and operated on under sterile conditions. The right knee joints in the immobilization group and exercise group were immobilized with external fixation at 120 degrees of flexion. Range of motion exercise was started from the day after immobilization. ROM exercise was performed in the exercise group once a day for 3 minutes, 6 days a week, for 2 weeks. [Result] The joint capsule in the immobilization group and exercise group showed narrowing of the collagen bundles in interstitial spaces but was less dense in the control group. In the immobilized group, a hyperplastic reaction was associated with infiltration into the articular cavity and adhesion to the surface of the articular cartilage. Conversely, in the exercise group, hyperplasia of tissue was localized to the synovial membrane. [Conclusion] This finding may suggest that ROM exercise induces some changes within the joint components and tissue metabolism.

  20. Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch.

    PubMed

    Uygun, Murat; Akduman, Begüm; Ergönül, Bülent; Aktaş Uygun, Deniz; Akgöl, Sinan; Denizli, Adil

    2015-01-01

    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 °C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 °C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and Km values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865 mg/mL, respectively. Vmax of immobilized amyloglucosidase was found to be (0.496 µmol/min) about four times less than that of free enzyme (2.020 µmol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54 mg/mL at the end of the 5 min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase.

  1. Covalent immobilization of invertase on PAMAM-dendrimer modified superparamagnetic iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Uzun, K.; Çevik, E.; Şenel, M.; Sözeri, H.; Baykal, A.; Abasıyanık, M. F.; Toprak, M. S.

    2010-10-01

    In this study, polyamidoamine (PAMAM) dendrimer was synthesized on the surface of superparamagnetite nanoparticles to enhance invertase immobilization. The amount of immobilized enzyme on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times (i.e., 250%) as much as that of magnetite nanoparticle modified with only amino silane. Maximum reaction rate ( V max) and Michaelis-Menten constant ( K m) were determined for the free and immobilized enzymes. Various characteristics of immobilized invertase such as; the temperature activity, thermal stability, operational stability, and storage stability were evaluated and results revealed that stability of the enzyme is improved upon immobilization.

  2. Uranium Immobilization in Wetland Soils

    NASA Astrophysics Data System (ADS)

    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

    In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

  3. A pilot-controlled study of a polymyxin B-immobilized hemoperfusion cartridge in patients with severe sepsis secondary to intra-abdominal infection.

    PubMed

    Vincent, Jean-Louis; Laterre, Pierre-François; Cohen, Jonathan; Burchardi, Hilmar; Bruining, Hajo; Lerma, Francisco Alvarez; Wittebole, Xavier; De Backer, Daniel; Brett, Stephen; Marzo, Dolores; Nakamura, Haruji; John, Stephanie

    2005-05-01

    Endotoxin is an important pathogenic trigger for sepsis. The polymyxin B-immobilized endotoxin removal hemoperfusion cartridge, Toraymyxin (hereafter PMX), has been shown to remove endotoxin in preclinical and open-label clinical studies. In a multicenter, open-label, pilot, randomized, controlled study conducted in the intensive care unit in six academic medical centers in Europe, 36 postsurgical patients with severe sepsis or septic shock secondary to intra-abdominal infection were randomized to PMX treatment of 2 h (n = 17) or standard therapy (n = 19). PMX was well tolerated and showed no significant side effects. There were no statistically significant differences in the change in endotoxin levels from baseline to 6 to 8 h after treatment or to 24 h after treatment between the two groups. There was also no significant difference in the change in interleukin (IL)-6 levels from baseline to 6 to 8 h after treatment or to 24 h after treatment between the two groups. Patients treated with PMX demonstrated significant increases in cardiac index (CI; P = 0.012 and 0.032 at days 1 and 2, respectively), left ventricular stroke work index (LVSWI, P = 0.015 at day 2), and oxygen delivery index (DO2I, P = 0.007 at day 2) compared with the controls. The need for continuous renal replacement therapy (CRRT) after study entry was reduced in the PMX group (P = 0.043). There was no significant difference between the groups in organ dysfunction as assessed by the Sequential Organ Failure Assessment (SOFA) scores from day 0 (baseline) to day 6. Treatment using the PMX cartridge is safe and may improve cardiac and renal dysfunction due to sepsis or septic shock. Further studies are needed to prove this effectiveness.

  4. Immobilized soybean hull peroxidase for the oxidation of phenolic compounds in coffee processing wastewater.

    PubMed

    Chagas, Pricila Maria Batista; Torres, Juliana Arriel; Silva, Maria Cristina; Corrêa, Angelita Duarte

    2015-11-01

    Chitosan beads were prepared, using glutaraldehyde as a crosslinking agent for the immobilization of soybean hull peroxidase (SBP). The activity of free and immobilized SBP was studied. The optimum pH was 6.0 for both the free and immobilized enzyme; however, enzyme activity became more dependent on the temperature after immobilization. This study evaluated the potential use of immobilized and free enzyme in the oxidation of caffeic acid, of synthetic phenolic solution (SPS) and of total phenolic compounds in coffee processing wastewater (CPW). Some factors, such as reaction time, amount of H2O2 and caffeic acid were evaluated, in order to determine the optimum conditions for enzyme performance. Both enzymes showed a potential in the removal of caffeic acid, SPS and CPW, and immobilized SBP had the highest oxidation performance. The immobilized enzyme showed a potential of 50% in the oxidation of caffeic acid after 4 consecutive cycles.

  5. Application of immobilized cells to the treatment of cyanide wastewater.

    PubMed

    Chen, C Y; Kao, C M; Chen, S C; Chien, H Y; Lin, C E

    2007-01-01

    Cyanide is highly toxic to living organisms, particularly in inactivating the respiration system by tightly binding to terminal oxidase. To protect the environment and water bodies, wastewater containing cyanide must be treated before discharging into the environment. Biological treatment is a cost-effective and environmentally acceptable method for cyanide removal compared with the other techniques currently in use. Klebsiella oxytoca (K. oxytoca), isolated from cyanide-containing industrial wastewater, has been shown to be able to biodegrade cyanide to non-toxic end products. The technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide (KCN) was used as the target compound and both alginate (AL) and cellulose triacetate (CTA) techniques were applied for the preparation of immobilized cells. Results from this study show that KCN can be utilized as the sole nitrogen source by K. oxytoca. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration, pH, and temperature. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH and temperature, especially in the system with CTA gel beads. Results show that a longer incubation period was required for KCN degradation using immobilized cells compared to the free suspended systems. This might be due to internal mass transfer limitations. Results also indicate that immobilized systems can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of the immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. Results reveal that the application of immobilized cells of K. oxytoca is advantageous

  6. Immobilization of β-galactosidase on modified polypropilene membranes.

    PubMed

    Vasileva, Nastya; Iotov, Vladislav; Ivanov, Yavor; Godjevargova, Tzonka; Kotia, Nana

    2012-12-01

    A new immobilized system: β-galactosidase-modified polypropylene membrane was created. It was obtained 13 different carriers by chemical modification of polypropylene membranes by two stages. The first stage is treatment with K(2)Cr(2)O(7) to receive carboxylic groups on membrane surface. The second stage is treatment with different modified agents ethylendiamine, hexamethylenediamine, hydrazine dihydrochloride, hydroxylamine, o-phenylenediamine, p-phenylenediamine, N,N'-dibenzyl ethylenediamine diacetate to receive amino groups. The quantity of the amino groups, carboxylic groups and the degree of hydrophilicity of unmodified and modified polypropilene membranes were determined. β-Galactosidase was chemically immobilized on the obtained carries by glutaraldehyde. The highest relative activity of immobilized enzyme was recorded at membrane modified with 10% hexamethylenediamine (Membrane 5) - 92.77%. The properties of immobilized β-galactosidase on different modified membranes - pH optimum, temperature optimum, pH stability and thermal stability were investigated and compared with those of free enzyme. The storage stability of all immobilized systems was studied. It was found that the most stable system is immobilized enzyme on Membrane 5. The system has kept 90% of its initial activity at 300th day (pH=6.8; 4°C). The stability of the free and immobilized β-galactosidase on the modified membrane 5 with 10% HMDA in aqueous solutions of alcohols - mono-, diol and triol was studied. The kinetics of enzymatic reaction of free and immobilized β-galactosidase on the modified membrane 5 at 20°C and 40°C and at the optimal pH for both forms of the enzyme were investigated. It was concluded that the modified agent - hexamethylenediamine, with long aliphatic chain ensures the best immobilized β-galactosidase system. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Enhanced stability of catalase covalently immobilized on functionalized titania submicrospheres.

    PubMed

    Wu, Hong; Liang, Yanpeng; Shi, Jiafu; Wang, Xiaoli; Yang, Dong; Jiang, Zhongyi

    2013-04-01

    In this study, a novel approach combing the chelation and covalent binding was explored for facile and efficient enzyme immobilization. The unique capability of titania to chelate with catecholic derivatives at ambient conditions was utilized for titania surface functionalization. The functionalized titania was then used for enzyme immobilization. Titania submicrospheres (500-600 nm) were synthesized by a modified sol-gel method and functionalized with carboxylic acid groups through a facile chelation method by using 3-(3,4-dihydroxyphenyl) propionic acid as the chelating agent. Then, catalase (CAT) was covalently immobilized on these functionalized titania submicrospheres through 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. The immobilized CAT retained 65% of its free form activity with a loading capacity of 100-150 mg/g titania. The pH stability, thermostability, recycling stability and storage stability of the immobilized CAT were evaluated. A remarkable enhancement in enzyme stability was achieved. The immobilized CAT retained 90% and 76% of its initial activity after 10 and 16 successive cycles of decomposition of hydrogen peroxide, respectively. Both the Km and the Vmax values of the immobilized CAT (27.4 mM, 13.36 mM/min) were close to those of the free CAT (25.7 mM, 13.46 mM/min).

  8. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    NASA Astrophysics Data System (ADS)

    Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

    2009-06-01

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  9. Enhanced growth of lactobacilli in soymilk upon immobilization on agrowastes.

    PubMed

    Teh, Sue-Siang; Ahmad, Rosma; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

    2010-04-01

    Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 microm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 degrees C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05).

  10. Waste immobilization process development at the Savannah River Plant

    SciTech Connect

    Charlesworth, D L

    1986-01-01

    Processes to immobilize various wasteforms, including waste salt solution, transuranic waste, and low-level incinerator ash, are being developed. Wasteform characteristics, process and equipment details, and results from field/pilot tests and mathematical modeling studies are discussed.

  11. SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes.

    PubMed

    Silveira, Célia M; Quintas, Pedro O; Moura, Isabel; Moura, José J G; Hildebrandt, Peter; Almeida, M Gabriela; Todorovic, Smilja

    2015-01-01

    Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic activity of cd1NiR from Marinobacter hydrocarbonoclasticus (Mhcd1) depends on the presence of its physiological redox partner, cytochrome c552 (cyt c552), we show here a detailed surface enhanced resonance Raman characterization of Mhcd1 and cyt c552 attached to biocompatible electrodes in conditions which allow direct electron transfer between the conducting support and immobilized proteins. Mhcd1 and cyt c552 are co-immobilized on silver electrodes coated with self-assembled monolayers (SAMs) and the electrocatalytic activity of Ag // SAM // Mhcd1 // cyt c552 and Ag // SAM // cyt c552 // Mhcd1 constructs is tested in the presence of nitrite. Simultaneous evaluation of structural and thermodynamic properties of the immobilized proteins reveals that cyt c552 retains its native properties, while the redox potential of apparently intact Mhcd1 undergoes a ~150 mV negative shift upon adsorption. Neither of the immobilization strategies results in an active Mhcd1, reinforcing the idea that subtle and very specific interactions between Mhcd1 and cyt c552 govern efficient intermolecular electron transfer and catalytic activity of Mhcd1.

  12. SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes

    PubMed Central

    Silveira, Célia M.; Quintas, Pedro O.; Moura, Isabel; Moura, José J. G.; Hildebrandt, Peter; Almeida, M. Gabriela; Todorovic, Smilja

    2015-01-01

    Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic activity of cd1NiR from Marinobacter hydrocarbonoclasticus (Mhcd1) depends on the presence of its physiological redox partner, cytochrome c552 (cyt c552), we show here a detailed surface enhanced resonance Raman characterization of Mhcd1 and cyt c552 attached to biocompatible electrodes in conditions which allow direct electron transfer between the conducting support and immobilized proteins. Mhcd1 and cyt c552 are co-immobilized on silver electrodes coated with self-assembled monolayers (SAMs) and the electrocatalytic activity of Ag // SAM // Mhcd1 // cyt c552 and Ag // SAM // cyt c552 // Mhcd1 constructs is tested in the presence of nitrite. Simultaneous evaluation of structural and thermodynamic properties of the immobilized proteins reveals that cyt c552 retains its native properties, while the redox potential of apparently intact Mhcd1 undergoes a ~150 mV negative shift upon adsorption. Neither of the immobilization strategies results in an active Mhcd1, reinforcing the idea that subtle and very specific interactions between Mhcd1 and cyt c552 govern efficient intermolecular electron transfer and catalytic activity of Mhcd1. PMID:26091174

  13. Electrochemical Study and Characterization of an Amperometric Biosensor Based on the Immobilization of Laccase in a Nanostructure of TiO2 Synthesized by the Sol-Gel Method

    PubMed Central

    Romero-Arcos, Mariana; Garnica-Romo, Ma. Guadalupe; Martínez-Flores, Héctor Eduardo

    2016-01-01

    Laccase amperometric biosensors were developed to detect the catechol compound. The laccase enzyme (LAC) immobilization was performed on nanostructures of (a) titania (TiO2); (b) titania/Nafion (TiO2/NAF) (both immobilized by the sol-gel method) and a third nanostructure, which consisted of a single biosensor composite of Nafion and laccase enzyme denoted as NAF/LAC. The Nafion was deposited on a graphite electrode and used to avoid “cracking” on the matrix. The TiO2 particle size was an average of 66 nm. FTIR spectroscopy vibration modes of different composites were determined. The electrochemical behavior of the biosensor was studied using electrochemical spectroscopy (EIS) and cyclic voltammetry (CV). The biosensor based on TiO2/NAF/LAC presented the best electro-chemical properties with regard to sensitivity, stability and detection limit after a period of 22 days. PMID:28773666

  14. Development and Validation of a Small Animal Immobilizer and Positioning System for the Study of Delivery of Intracranial and Extracranial Radiotherapy Using the Gamma Knife System.

    PubMed

    Awan, Musaddiq J; Dorth, Jennifer; Mani, Arvind; Kim, Haksoo; Zheng, Yiran; Mislmani, Mazen; Welford, Scott; Yuan, Jiankui; Wessels, Barry W; Lo, Simon S; Letterio, John; Machtay, Mitchell; Sloan, Andrew; Sohn, Jason W

    2017-04-01

    The purpose of this research is to establish a process of irradiating mice using the Gamma Knife as a versatile system for small animal irradiation and to validate accurate intracranial and extracranial dose delivery using this system. A stereotactic immobilization device was developed for small animals for the Gamma Knife head frame allowing for isocentric dose delivery. Intercranial positional reproducibility of a reference point from a primary reference animal was verified on an additional mouse. Extracranial positional reproducibility of the mouse aorta was verified using 3 mice. Accurate dose delivery was validated using film and thermoluminescent dosimeter measurements with a solid water phantom. Gamma Knife plans were developed to irradiate intracranial and extracranial targets. Mice were irradiated validating successful targeted radiation dose delivery. Intramouse positional variability of the right mandible reference point across 10 micro-computed tomography scans was 0.65 ± 0.48 mm. Intermouse positional reproducibility across 2 mice at the same reference point was 0.76 ± 0.46 mm. The accuracy of dose delivery was 0.67 ± 0.29 mm and 1.01 ± 0.43 mm in the coronal and sagittal planes, respectively. The planned dose delivered to a mouse phantom was 2 Gy at the 50% isodose with a measured thermoluminescent dosimeter dose of 2.9 ± 0.3 Gy. The phosphorylated form of member X of histone family H2A (γH2AX) staining of irradiated mouse brain and mouse aorta demonstrated adjacent tissue sparing. In conclusion, our system for preclinical studies of small animal irradiation using the Gamma Knife is able to accurately deliver intracranial and extracranial targeted focal radiation allowing for preclinical experiments studying focal radiation.

  15. Gelatin-tricalcium phosphate membranes immobilized with NGF, BDNF, or IGF-1 for peripheral nerve repair: an in vitro and in vivo study.

    PubMed

    Chen, Ming-Hong; Chen, Pei-Ru; Chen, Mei-Hsiu; Hsieh, Sung-Tsang; Lin, Feng-Huei

    2006-12-15

    In the present study, NGF, BNDF from the neurotrophin family and IGF-1 were covalently immobilized on gelatin-tricalcium phosphate (GTG) membrane using carbodiimide. We investigated the effects of these growth factors released from the GTG composites on cultured PC12 cells and sciatic nerve regeneration across a 10-mm-long gap in rats. In PC12 cell culture, the total protein content and MTT assay indicated more cell attachment on the composites modified with growth factors. The IGF-1 group showed a higher survival promotion effect on PC12 cells than did BDNF and NGF groups. On the other hand, NGF released from the composite showed the highest level of neuritogenesis for PC12 cells in neurite outgrowth assay. In the animal study, the GTG conduits modified with various growth factors were well tolerated by the host tissue. In the regenerated nerves, the number of the axons per unit area of the BDNF group was significantly higher than that of NGF and GTG groups but similar to that of IGF-1 group. However, the average axon size was the largest in NGF group. This result was in concordance with the neurite outgrowth assay in which NGF showed the highest neuritogenic potential. In the assessment of motor and sensory recovery after nerve repair, conduits modified with various neurotrophic factors showed a more favorable outcome in compound muscle action potential. The BDNF group had a better gastrocnemic muscle weight ratio than blank GTG repair. Nevertheless, the different effects of GTG conduits modified with various neurotrophic factors on functional recovery cannot be simply illustrated in the sciatic function index.

  16. Weldon Spring, Missouri, Raffinate Pits 1, 2, 3, and 4: Preliminary grout development screening studies for in situ waste immobilization

    SciTech Connect

    McDaniel, E.W.; Gilliam, T.M.; Dole, L.R.; West, G.A.

    1987-04-01

    Results of Oak Ridge National Laboratory's initial support program to develop a preliminary grout formula to solidify in situ the Weldon Spring waste are presented. The screening study developed preliminary formulas based on a simulated composite waste and then tested the formulas on actual waste samples. Future data needs are also discussed. 1 ref., 6 figs., 9 tabs.

  17. Student Collaboration in a Series of Integrated Experiments to Study Enzyme Reactor Modeling with Immobilized Cell-Based Invertase

    ERIC Educational Resources Information Center

    Taipa, M. A^ngela; Azevedo, Ana M.; Grilo, Anto´nio L.; Couto, Pedro T.; Ferreira, Filipe A. G.; Fortuna, Ana R. M.; Pinto, Ine^s F.; Santos, Rafael M.; Santos, Susana B.

    2015-01-01

    An integrative laboratory study addressing fundamentals of enzyme catalysis and their application to reactors operation and modeling is presented. Invertase, a ß-fructofuranosidase that catalyses the hydrolysis of sucrose, is used as the model enzyme at optimal conditions (pH 4.5 and 45 °C). The experimental work involves 3 h of laboratory time…

  18. Student Collaboration in a Series of Integrated Experiments to Study Enzyme Reactor Modeling with Immobilized Cell-Based Invertase

    ERIC Educational Resources Information Center

    Taipa, M. A^ngela; Azevedo, Ana M.; Grilo, Anto´nio L.; Couto, Pedro T.; Ferreira, Filipe A. G.; Fortuna, Ana R. M.; Pinto, Ine^s F.; Santos, Rafael M.; Santos, Susana B.

    2015-01-01

    An integrative laboratory study addressing fundamentals of enzyme catalysis and their application to reactors operation and modeling is presented. Invertase, a ß-fructofuranosidase that catalyses the hydrolysis of sucrose, is used as the model enzyme at optimal conditions (pH 4.5 and 45 °C). The experimental work involves 3 h of laboratory time…

  19. Stablization and immobilization of excess Russian weapons origin plutonium

    SciTech Connect

    Jardine, L.J.; Borisov, G.B.; Mansourov, O.A.

    1998-04-10

    This paper summarizes a strategy, logic, and framework for the development of a capability for immobilizing excess Russian weapons origin plutonium by the year 2004. We describe the initial activities underway in Russia and a schedule to implement the strategy. These activities include engineering feasibility studies of the select facilities at the Mayak and Krasnoyarsk industrial sites, and research and development studies on plutonium glass and ceramic immobilization forms at several Russian institutes.

  20. Photochemically Initiated Single Polymer Immobilization

    PubMed Central

    2015-01-01

    This Concept article surveys methods for attaching single polymer molecules on solid substrates. A general approach to single polymer immobilization based on the photochemistry of perfluorophenylazides is elaborated. PMID:17444538

  1. Treating Wastewater With Immobilized Enzymes

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1991-01-01

    Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

  2. Treating Wastewater With Immobilized Enzymes

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1991-01-01

    Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

  3. Optimizing immobilization of avidin on surface-modified magnetic nanoparticles: characterization and application of protein-immobilized nanoparticles.

    PubMed

    Yang, Tao; Sun, Shuguo; Ma, Meihu; Lin, Qinlu; Zhang, Lin; Li, Yan; Luo, Feijun

    2015-10-01

    A simple optimization method of immobilization of avidin on magnetic nanoparticles (MNPs)' surface was proposed in this study. The avidin-immobilized MNPs were then developed and used to immobilize a model enzyme [Horseradish peroxidase (HRP)]. The loading capacity (LC) and activity of avidin-immobilized MNPs were optimized through selecting the most appropriate nanoparticle's size and shape, glutaraldehyde concentration, cross-linking reaction time, ultrasonic processing time, and initial concentration of avidin. The LC under optimized conditions was 63.37 ± 1.29 mg avidin/g MNPs, and the immobilized protein was still able to maintain its high biological activity of 10.86 ± 0.13 U/mg (biotin-binding activity of nature avidin was 14.1 U/mg) and better thermal stability compared to free avidin. A highly reusable, stable, and easily recovered immobilized HRP was obtained using MNPs as carriers. The immobilized HRP was reused repeatedly more than 9 times and retained more than 65 % of its original activity.

  4. 1-Step Versus 2-Step Immobilization of Alkaline Phosphatase and Bone Morphogenetic Protein-2 onto Implant Surfaces Using Polydopamine

    PubMed Central

    Nijhuis, Arnold W.G.; van den Beucken, Jeroen J.J.P.; Boerman, Otto C.; Jansen, John A.

    2013-01-01

    Immobilization of biomolecules onto implant surfaces is highly relevant in many areas of biomaterial research. Recently, a 2-step immobilization procedure was developed for the facile conjugation of biomolecules onto various surfaces using self-polymerization of dopamine into polydopamine. In the current study, a 1-step polydopamine-based approach was applied for alkaline phosphatase (ALP) and bone morphogenetic protein-2 (BMP-2) immobilization, and compared to the conventional 2-step polydopamine-based immobilization and plain adsorption. To this end, ALP and BMP-2 were immobilized onto titanium and polytetrafluoroethylene (PTFE) substrates. The absolute quantity and biological activity of immobilized ALP were assessed quantitatively to compare the three types of immobilization. Plain adsorption of both ALP and BMP-2 was inferior to both polydopamine-based immobilization approaches. ALP was successfully immobilized onto titanium and PTFE surfaces via the 1-step approach, and the immobilized ALP retained its enzymatic activity. Using the 1-step approach, the amount of immobilized ALP was increased twofold to threefold compared to the conventional 2-step immobilization process. In contrast, more BMP-2 was immobilized using the conventional 2-step immobilization approach. Retention of ALP and BMP-2 was measured over a period of 4 weeks and was found to be similar for the 1-step and 2-step methods and far superior to the retention of adsorbed biomolecules due to the formation of covalent linkages between catechol moieties and immobilized proteins. The biological behavior of ALP and BMP-2 coatings immobilized using polydopamine (1- and 2-step) as well as adsorption was assessed by culturing rat bone marrow cells, which revealed that the cell responses to the various experimental groups were not statistically different. In conclusion, the 1-step polydopamine-based immobilization method was shown to be more efficient for immobilization of ALP, whereas the conventional 2

  5. 1-step versus 2-step immobilization of alkaline phosphatase and bone morphogenetic protein-2 onto implant surfaces using polydopamine.

    PubMed

    Nijhuis, Arnold W G; van den Beucken, Jeroen J J P; Boerman, Otto C; Jansen, John A; Leeuwenburgh, Sander C G

    2013-08-01

    Immobilization of biomolecules onto implant surfaces is highly relevant in many areas of biomaterial research. Recently, a 2-step immobilization procedure was developed for the facile conjugation of biomolecules onto various surfaces using self-polymerization of dopamine into polydopamine. In the current study, a 1-step polydopamine-based approach was applied for alkaline phosphatase (ALP) and bone morphogenetic protein-2 (BMP-2) immobilization, and compared to the conventional 2-step polydopamine-based immobilization and plain adsorption. To this end, ALP and BMP-2 were immobilized onto titanium and polytetrafluoroethylene (PTFE) substrates. The absolute quantity and biological activity of immobilized ALP were assessed quantitatively to compare the three types of immobilization. Plain adsorption of both ALP and BMP-2 was inferior to both polydopamine-based immobilization approaches. ALP was successfully immobilized onto titanium and PTFE surfaces via the 1-step approach, and the immobilized ALP retained its enzymatic activity. Using the 1-step approach, the amount of immobilized ALP was increased twofold to threefold compared to the conventional 2-step immobilization process. In contrast, more BMP-2 was immobilized using the conventional 2-step immobilization approach. Retention of ALP and BMP-2 was measured over a period of 4 weeks and was found to be similar for the 1-step and 2-step methods and far superior to the retention of adsorbed biomolecules due to the formation of covalent linkages between catechol moieties and immobilized proteins. The biological behavior of ALP and BMP-2 coatings immobilized using polydopamine (1- and 2-step) as well as adsorption was assessed by culturing rat bone marrow cells, which revealed that the cell responses to the various experimental groups were not statistically different. In conclusion, the 1-step polydopamine-based immobilization method was shown to be more efficient for immobilization of ALP, whereas the conventional 2

  6. Potentiometric biosensor for determination of urea in milk using immobilized Arthrobacter creatinolyticus urease.

    PubMed

    Ramesh, Rajendran; Puhazhendi, Puhazhselvan; Kumar, Jitendra; Gowthaman, Marichetti Kuppuswami; D'Souza, Stanislaus Francis; Kamini, Numbi Ramudu

    2015-04-01

    The extracellular urease from Arthrobacter creatinolyticus was partially purified by ammonium sulfate precipitation and immobilized on PAN [poly(acrylonitrile-methylmethacrylate-sodium vinylsulfonate)] membrane. The urease immobilized PAN membrane exhibited an activity of 97.92U/cm(2) under the optimum conditions of 1.0% enzyme concentration, 15% glutaraldehyde, 24h immobilization time and temperature of 4°C. The changes in surface morphology of the membrane after immobilization were studied by SEM and ATR-FTIR analysis. Immobilized membrane was associated with potentiometric electrode for calibration of biosensor and the results showed a linear response for wide range of urea concentration from 1 to 100mM. The immobilized urease had good storage stability for a period of 70days at 4°C and could be effectively reused for 13cycles. Urease immobilized membrane was also employed in analysis of urea spiked milk samples.

  7. Antimony (Sb) and lead (Pb) in contaminated shooting range soils: Sb and Pb mobility and immobilization by iron based sorbents, a field study.

    PubMed

    Okkenhaug, Gudny; Grasshorn Gebhardt, Karl-Alexander; Amstaetter, Katja; Bue, Helga Lassen; Herzel, Hannes; Mariussen, Espen; Rossebø Almås, Åsgeir; Cornelissen, Gerard; Breedveld, Gijs D; Rasmussen, Grete; Mulder, Jan

    2016-04-15

    Small-arm shooting ranges often receive a significant input of lead (Pb), copper (Cu) and antimony (Sb) from ammunition. The goal of the present study was to investigate the mobility, distribution and speciation of Pb and Sb pollution under field conditions in both untreated and sorbent-amended shooting range soil. Elevated Sb (19-349μgL(-1)) and Pb (7-1495μgPbL(-1)) concentrations in the porewater of untreated soil over the four-year test period indicated a long-term Sb and Pb source to the adjacent environment in the absence of remedial measures. Mixing ferric oxyhydroxide powder (CFH-12) (2%) together with limestone (1%) into the soil resulted in an average decrease of Sb and Pb porewater concentrations of 66% and 97%, respectively. A similar reduction was achieved by adding 2% zerovalent iron (Fe°) to the soil. The remediation effect was stable over the four-year experimental period indicating no remobilization. Water- and 1M NH4NO3-extractable levels of Sb and Pb in field soil samples indicated significant immobilization by both treatments (89-90% for Sb and 89-99% for Pb). Results from sequential extraction analysis indicate fixation of Sb and Pb in less accessible fractions like amorphous iron oxides or even more crystalline and residual mineral phases, respectively. This work shows that amendment with Fe-based sorbents can be an effective method to reduce the mobility of metals both in cationic and anionic form in polluted shooting range soil.

  8. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO2-Fe and TiO2-reduced graphene oxide nanocomposites immobilized on optical fibers.

    PubMed

    Lin, Lu; Wang, Huiyao; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei

    2017-03-08

    Incorporating reduced graphene oxide (rGO) or Fe(3+) ions in TiO2 photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO2-Fe and TiO2-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO2-rGO and TiO2-Fe nanocomposites. Doping Fe into TiO2 particles (2.40eV) could reduce more band gap energy than incorporating rGO (2.85eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO2 decreased significantly the intensity of TiO2 photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO2-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO2-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO2-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO2-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic activity.

  9. Clinical effects of direct hemoperfusion using a polymyxin-B immobilized column in solid organ transplanted patients with signs of severe sepsis and septic shock. A pilot study.

    PubMed

    Ruberto, F; Pugliese, F; D'Alio, A; Martelli, S; Bruno, K; Marcellino, V; Summonti, D; Celli, P; Perrella, S; Cappannoli, A; Pietropaoli, C; Tosi, A; Diana, B; Novelli, G; Rossi, M; Ginanni-Corradini, S; Ferretti, G; Berloco, P B; Pietropaoli, P

    2007-10-01

    Polymyxin B (PMX-B) is a polycationic antibiotic, known to bind the lipid A portion of endotoxin, a cell wall component found exclusively in gram negative bacteria (GNB). An extracorporeal hemoperfusion device (TORAYMYXIN) has been developed: PMX is covalently bound on the surface of an insoluble carrier material so that the endotoxin can be inactivated in the blood without exerting its toxicity on the brain and kidney. The aim of this study was to clarify the efficacy, safety and clinical effects of direct hemoperfusion with an immobilized polymyxin-B fiber column (DHP-PMX) in solid organ transplanted patients with severe sepsis or septic shock. From June 2004 to May 2005, 15 patients (10 men and 5 women), mean age 55 years old (46-65 range), underwent kidney or liver transplantation and developed severe sepsis or septic shock, as defined by the Consensus Conference of American College Physicians/Society of Critical Care Medicine (ACCP/SCCM) criteria. GNB were detected in all the patients receiving conventional treatments including antibiotic therapy, vasopressive or inotropic agents, and ventilation support. The DHP-PMX treatment was performed three times in each patient. Hemodynamic and respiratory parameters, dosage of vasopressor/inotropic drugs were assessed at baseline and after each treatment. No adverse events occurred. From baseline to 3rd treatment, mean arterial pressure (MAP) was increased (from 63+/-5 to 83+/-4 mmHg), while the dosage of dobutamine (from 7.5+/-3 to 3+/-2 mcg/kg/min) and noradrenaline (from 1.3+/-0.45 to 0.05+/-0.02 mcg/kg/min) were reduced. The PaO2/FiO2 ratio increased (from 234+/-38.47 to 290+/-107.48 mmHg). The use of DHP-PMX in association with conventional therapy may be an important aid in patients with sepsis.

  10. Nanoporous Gold as a Solid Support for Protein Immobilization for the Development of Immunoassays, and for Biomolecular Interaction Studies

    NASA Astrophysics Data System (ADS)

    Pandey, Binod Prasad

    Nanoporous gold (NPG) is a versatile material of high surface area to volume ratio that can be readily modified with self-assembled monolayers of alkanethiols to which biomolecules can be linked. NPG presents new opportunities for the development of immunoassays, and for the development of carbohydrate based assays. This thesis explores the use of NPG as a support for self-assembled monolayers, their linkage to antibody-enzyme conjugates for immunoassay development, and for the study and application of carbohydrate-protein interactions. Direct kinetic electrochemical immunoassays were developed on NPG for prostate specific antigen (PSA) and carcinoembryonic antigen (CEA). The decrease in enzymatic conversion of p-aminophenylphosphate to p-aminophenol, by alkaline phosphatase conjugated to an antibody, due to steric hindrance caused by the presence of antigen on antibody, was observed as a drop in peak current in square-wave voltammetry. Detection limit of these assays was 0.075 ng mL -1 and 0.015 ng mL-1 for PSA and CEA, respectively. Similarly, the linear range of determination of these biomarkers extended up to 30 ng mL-1 and 10 ng mL-1 for PSA and CEA, respectively. Minimal interference was observed using newborn calf serum as a substitute for the human serum matrix. A rapid and sensitive enzyme linked lectinsorbant assay was also developed for the study of glycoprotein-lectin interactions on the NPG surface. Self-assembled monolayers of alkanethiols on NPG were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Similarly, the applicability of this surface for the formation of carbohydrate monolayers and its application for lectin carbohydrate interactions was also studied. Pure and mixed SAMs of 8-mercaptooctyl β-D-mannopyranoside (αMan-C8-SH) and α-D-Gal-(1→4)-β-D-Gal-(1α)-D-Glc-1-O-mercaptooctane (Gb3-C8-SH) with alkanethiols having varying tail groups were prepared. Binding affinity and binding kinetics of concanavalin A

  11. Cellulase immobilization on magnetic nanoparticles encapsulated in polymer nanospheres.

    PubMed

    Lima, Janaina S; Araújo, Pedro H H; Sayer, Claudia; Souza, Antonio A U; Viegas, Alexandre C; de Oliveira, Débora

    2017-04-01

    Immobilization of cellulases on magnetic nanoparticles, especially magnetite nanoparticles, has been the main approach studied to make this enzyme, economically and industrially, more attractive. However, magnetite nanoparticles tend to agglomerate, are very reactive and easily oxidized in air, which has strong impact on their useful life. Thus, it is very important to provide proper surface coating to avoid the mentioned problems. This study aimed to investigate the immobilization of cellulase on magnetic nanoparticles encapsulated in polymeric nanospheres. The support was characterized in terms of morphology, average diameter, magnetic behavior and thermal decomposition analyses. The polymer nanospheres containing encapsulated magnetic nanoparticles showed superparamagnetic behavior and intensity average diameter about 150 nm. Immobilized cellulase exhibited broader temperature stability than in the free form and great reusability capacity, 69% of the initial enzyme activity was maintained after eight cycles of use. The magnetic support showed potential for cellulase immobilization and allowed fast and easy biocatalyst recovery through a single magnet.

  12. The Boxer's Fracture: Splint Immobilization Is Not Necessary.

    PubMed

    Dunn, John C; Kusnezov, Nicholas; Orr, Justin D; Pallis, Mark; Mitchell, Justin S

    2016-05-01

    Fractures of the fifth metacarpal neck, or boxer's fractures, are common, particularly among young men. Because of the high frequency of this injury, there is a considerable range of treatment options. The purpose of this systematic review was to determine whether reduction and splint or cast immobilization is necessary for fractures of the fifth metacarpal neck. The authors conducted a systematic review of all published studies that randomized these fractures to cast immobilization vs treatment with soft wrap without reduction. Cast immobilization is not superior to soft wrap without reduction in most cases. The study found that reduction and cast immobilization is not necessary for boxer's fractures. [Orthopedics. 2016; 39(3):188-192.].

  13. Immunosuppressive agent leflunomide: a SWNTs-immobilized dihydroortate dehydrogenase inhibitory effect and computational study of its adsorption properties on zigzag single walled (6,0) carbon and boron nitride nanotubes as controlled drug delivery devices.

    PubMed

    Raissi, Heidar; Mollania, Fariba

    2014-06-02

    Leflunomide [HWA 486 or RS-34821, 5-methyl-N-(4trifluoromethylphenyl)-4-isoxazole carboximide] is an immunosuppressive agent effective in the treatment of rheumatoid arthritis. Dihydroortate dehydrogenase (DHODH, EC 1.3.3.1) immobilization on the nanotubes was carried out and biochemical characterization of free and immobilized enzyme was determined. In comparison with free enzyme, the immobilized DHODH showed improved stability and reusability for investigation of inhibition pattern of drugs such as leflunomide. The experimental data showed that, DHODH was inhibited by the active metabolite of leflunomide (RS-61980) with a Ki and KI of 0.82 and 0.06 mM, respectively. Results exhibited mixed-type inhibition kinetics towards dihydroorotate as a substrate in the free and immobilized enzyme. Furthermore, the behavior of anticancer drug leflunomide adsorbed on the external surface of zigzag single walled (6,0) carbon and boron nitride nanotubes (SWCNT and SWBNNT) was studied by means of DFT calculations at the B3LYP/6-31G(*) level of theory. The larger adsorption energies and charges transfer showed that the adsorption of leflunomide onto SWBNNT is more stable than that the adsorption of leflunomide onto SWCNT. Frontier molecular orbitals (HOMO and LUMO) suggest that adsorption of leflunomide onto SWBNNT behave as charge transfer compounds with leflunomide as an electron donor and SWBNNT as an electron acceptor. Thus, nanotubes (NTs) have been proposed and actively explored as multipurpose innovative carriers for drug delivery and diagnostic application. The AIM theory has been also applied to analyze the properties of the bond critical points: their electron densities and their laplacians. Also, the natural bond orbital (NBO) calculations were performed to derive natural atomic orbital occupancies, and partial charges of the interacting atoms in the equilibrium tube-molecule distance. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. N-15 NMR study of the immobilization of 2,4- and 2,6-dinitrotoluene in aerobic compost.

    PubMed

    Thorn, Kevin A; Pennington, Judith C; Kennedy, Kay R; Cox, Larry G; Hayes, Charolett A; Porter, Beth E

    2008-04-01

    Large-scale aerobic windrow composting has been used to bioremediate washout lagoon soils contaminated with the explosives TNT (2,4,6-trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) at several sites within the United States. We previously used 15N NMR to investigate the reduction and binding of T15NT in aerobic bench-scale reactors simulating the conditions of windrow composting. These studies have been extended to 2,4-dinitrotoluene (2,4DNT) and 2,6-dinitrotoluene (2,6DNT), which, as impurities in TNT, are usually presentwherever soils have been contaminated with TNT. Liquid-state 15N NMR analyses of laboratory reactions between 4-methyl-3-nitroaniline-15N, the major monoamine reduction product of 2,4DNT, and the Elliot soil humic acid, both in the presence and absence of horseradish peroxidase, indicated that the amine underwent covalent binding with quinone and other carbonyl groups in the soil humic acid to form both heterocyclic and non-heterocyclic condensation products. Liquid-state 15N NMR analyses of the methanol extracts of 20 day aerobic bench-scale composts of 2,4-di-15N-nitrotoluene and 2,6-di-15N-nitrotoluene revealed the presence of nitrite and monoamine, but not diamine, reduction products, indicating the occurrence of both dioxygenase enzyme and reductive degradation pathways. Solid-state CP/MAS 15N NMR analyses of the whole composts, however, suggested that reduction to monoamines followed by covalent binding of the amines to organic matter was the predominant pathway.

  15. N-15 NMR study of the immobilization of 2,4- and 2,6-dinitrotoluene in aerobic compost

    USGS Publications Warehouse

    Thorn, K.A.; Pennington, J.C.; Kennedy, K.R.; Cox, L.G.; Hayes, C.A.; Porter, B.E.

    2008-01-01

    Large-scale aerobic windrow composting has been used to bioremediate washout lagoon soils contaminated with the explosives TNT (2,4,6- trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) at several sites within the United States. We previously used 15N NMR to investigate the reduction and binding of T15NT in aerobic bench -scale reactors simulating the conditions of windrow composting. These studies have been extended to 2,4-dinitrotoluene (2,4DNT) and 2,6-dinitrotoluene (2,6DNT), which, as impurities in TNT, are usually present wherever soils have been contaminated with TNT. Liquid-state 15N NMR analyses of laboratory reactions between 4-methyl-3-nitroaniline-15N, the major monoamine reduction product of 2,4DNT, and the Elliot soil humic acid, both in the presence and absence of horseradish peroxidase, indicated that the amine underwent covalent binding with quinone and other carbonyl groups in the soil humic acid to form both heterocyclic and non-heterocyclic condensation products. Liquid-state 15N NMR analyses of the methanol extracts of 20 day aerobic bench-scale composts of 2,4-di-15N-nitrotoluene and 2,6-di-15N-nitrotoluene revealed the presence of nitrite and monoamine, but not diamine, reduction products, indicating the occurrence of both dioxygenase enzyme and reductive degradation pathways. Solid-state CP/MAS 15N NMR analyses of the whole composts, however, suggested that reduction to monoamines followed by covalent binding of the amines to organic matter was the predominant pathway. ?? 2008 American Chemical Society.

  16. Periodic operation of immobilized live cell bioreactors

    SciTech Connect

    Mehta, N.

    1988-01-01

    A complete system for computer-assisted fermentation research was set up. The system consisted of a 16 liter laboratory fermentor connected to a mass spectrometer for off-gas analysis, a flow injection analyzer for on-line enzymatic and colorimetric analysis, and an on-line HPLC. This system was interfaced to a Micro VAX II computer. The kinetics of growth and candicidin production by S. griseus in complex and in synthetic media were investigated. On-line glucose analysis of the fermentation was used to identify nutrient limitation by multiple substrates during the fermentation. The growth kinetics of S. griseus under limitation by two nutrients were studied. The Monod type of model was used to analyze cell growth under multiple substrate limitation. Regions of phosphate limitation were identified by analysis of the environmental state space. Based on this analysis the nutrient medium for the forced periodic operation of the immobilized bioreactor was developed. A lumped model for cell growth and candicidin production in an immobilized live cell bioreactor was developed. The model was used to perform a simulation study of the periodic operation of an immobilized bioreactor. Finally, an immobilzed bioreactor with forced periodic operation was used to study the effect of cycling frequency on reactor performance. The results of the studies on the periodic operation suggest that periodically operated immobilized live cell bioreactors can provide a potent alternative for the production of non-growth associated biochemicals, as compared to free cell fermentations, pulsed fermentations with process cycle regeneration, and non-regenerated bioreactors. This work has demonstrated that by frequent pulsing of growth limiting nutrient, stable extended production can be obtained at high specific cellular productivities.

  17. Synthesis of bi-metallic Au-Ag nanoparticles loaded on functionalized MCM-41 for immobilization of alkaline protease and study of its biocatalytic activity

    NASA Astrophysics Data System (ADS)

    Sadjadi, M. S.; Farhadyar, N.; Zare, K.

    2009-10-01

    In this work, Au-Ag nanoparticles (Au-Ag-bi-MNPs) have been prepared on amine functionalized Si-MCM-41 (NH 2-Si-MCM-41) particles through a reduction of AgNO 3 and HAuCl 4 by NaBH 4 at ambient conditions. Au-Ag-bi-MNPs loaded on the NH2-Si-MCM-41, provide a good biocompatible surface for immobilization of the enzyme alkaline protease. This immobilization, presumably due to bonding between core shell nanoparticles and OH in serine 183 in alkaline protease seems to be of an ionic exchange nature. We found that the alkaline protease immobilized on the Au-Ag-bi-MNPs/Si-MCM-41 is an active biocatalyst, stable at different pH and temperature. The bio catalytic activity of free alkaline protease in solution was 64 U/mg (Units per milligram), whereas that of the alkaline protease immobilized on Au-Ag-bi-MNPs/Si-MCM-41 was 75 U/mg. This improvement of the biocatalytic activity may be due to a really increased activity per molecule of immobilized enzyme or to a purification of the enzyme. The alkaline protease molecules immobilized on the (Au-Ag)/ NH 2-MCM-41 surface retained as much as 80% of the catalytic activity recorded at pH=8, and showed significant catalytic activity of alkaline protease in the bioconjugate material. The biocatalytic materials were easily separated from the reaction medium by mild centrifugation and exhibits excellent reuse and stability characteristics over four successive cycles. The optimum temperature ranged from 35 ∘C-55 ∘C and pH=8 for bioactivity of the alkaline protease in the assembly system was observed to be higher than that of the free enzyme in solution. The enzyme biocatalytic activity was monitored by UV-visible spectroscopy. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and dispersive analysis of X-RAY (EDAX) were used to characterize the size and morphology of the prepared materials.

  18. Cellulase immobilized on modified nylon for saccharification of cellulose

    SciTech Connect

    Jain, P.; Wilkins, E.S.

    1987-01-01

    The present study deals with the immobilization of cellulase on nylon and nylon incorporated with glass. The immobilized and free enzymes were compared in terms of their yields, using untreated sawdust (yellow pine wood) and carboxymethylcellulose (CMC) as substrates, at a standard pH and temperature. Also, the sawdust was pretreated with 1% alkaline hydrogen peroxide and the yield compared with the untreated sawdust hydrolysis to determine the importance of the substrate pretreatment.

  19. Status of plutonium ceramic immobilization processes and immobilization forms

    SciTech Connect

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

    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. Continuous fermentation: improvement of cell immobilization by zeta potential measurement

    SciTech Connect

    Michaux, M.; Paquot, M.; Baijot, B.; Thonart, P.

    1982-01-01

    The influence of various agents such as inulin, proteins, and cationic polymers on the zeta potential of yeast cells has been studied. With various agents, it appears feasible to give a positive charge to the cell and a negative one to the carrier. Under these conditions, the yield of immobilization (mg cells/g support) is significantly improved. This is the case with various agents such as proteins and cationic polymers. For example, the yeild of cell immobilization (Saccharomyces) on sawdust varied from 94.2 to 145.8 mg/g of support with addition of gelatin (0.05%). The results demonstrate the influence of zeta potential on cell immobilization by adsorption. These immobilized cells are advantageously used in continuous production of ethanol. 3 figures, 8 tables.

  1. Rational surface silane modification for immobilizing glucose oxidase.

    PubMed

    Tian, Feibao; Guo, Yi; Lin, Feifei; Zhang, Yumei; Yuan, Qipeng; Liang, Hao

    2016-06-01

    Glucose oxidase (GOx) has many significant applications in biosensor and biocatalysis. In this study, we firstly quantitatively analyzed the binding efficiency of (3-aminopropyl) trimethoxysilane (APTES) modified onto the surface of GOx. It was found that the contents of the grafted silane did not significantly influence the relative activities and tertiary structures of all surface modified GOxs. Immobilization ratio and relative activity of all instances of APTES modified GOx increased, compared with those of native enzyme. However, good stability of immobilized GOx at extreme pH and high temperature could only be obtained when modified protein with low binding silane content. At pH 2.0, the immobilized GOx with low binding content showed a more than 600% activity, compared to the free enzyme. Therefore, rational surface modification would be beneficial to improving the activity and stability of immobilized enzyme as well as increasing loading amount. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Immobilization of enzyme on dimethyl-aminated nylon gels

    SciTech Connect

    Miyama, H.; Kawate, M.; Nosaka, Y.

    1985-10-01

    Miyama and co-workers have reported that dimethyl-aminated Nylon is a good material for the immobilization of enzyme after being quaternized. Also, they found a good correlation between the apparent Michaelis constant of the immobilized enzyme and the diffusion constant of the substrate in the matrix, and that between activity of the immobilized enzyme and interfacial free energy of the matrix. In their experiments, Nylon films of low degree of dimethylamination were used. In the present study, dimethylaminated Nylon of high degree of dimethylamination was quaternized by cationic oligomers having two functional groups. Thus, hydrogels were obtained, where the degree of cross-linking and the density of cation could be varied by changing the feeding amount and the length of cross-linking oligomers. These gels were then tested for the immobilization of urease and glucose oxidase. 9 references.

  3. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  4. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  5. Heparin-conjugated gelatin as a growth factor immobilization scaffold.

    PubMed

    Nakamura, Shintaro; Kubo, Takafumi; Ijima, Hiroyuki

    2013-05-01

    Tissue engineering requires growth factors, cells and a scaffold to permit effective tissue regeneration. This study aimed to develop a scaffold with a focus on immobilizing growth factors within gelatin. We focused on the extracellular matrix and developed a heparin-conjugated gelatin (Hep-gela). Conjugation was confirmed using the alcian blue assay and X-ray diffraction patterns. The mechanical strength and stability of the Hep-gela gel in protease solution were improved compared with collagen gel. Hep-gela was able to immobilize vascular endothelial growth factor (VEGF) even in the presence of albumin, with an efficiency of 54.2%. Immobilized VEGF promoted proliferation of human umbilical vein endothelial cells. Hep-gela-immobilized VEGF maintained its native biological activity. In summary, Hep-gela has the potential to become an effective material in the field of regenerative medicine.

  6. Immobilizing PEO-PPO-PEO triblock copolymers on hydrophobic surfaces and its effect on protein and platelet: a combined study using QCM-D and DPI.

    PubMed

    Jin, Jing; Huang, Fujian; Hu, Yu; Jiang, Wei; Ji, Xiangling; Liang, Haojun; Yin, Jinghua

    2014-11-01

    Dual polarization interferometry was used to monitor the immobilization dynamics of four Pluronics on hydrophobic surfaces and to elucidate the effect of Pluronic conformation on protein adsorption. The proportion of hydrophobic chain segments and not the length of the hydrophobic chain can influence the chain densities of the Pluronics. The immobilized densities of the Pluronics resulted from competition between the hydration of polyethylene oxide (PEO) in the aqueous solution and the hydrophobic interaction of polypropylene oxide on the substrate. P-123 obtained the largest graft mass (2.89±0.25 ng/mm2) because of the dominant effect of hydrophobic interactions. Hydrophobic segments of P-123 were anchored slowly and step-wise on the C18 substrate. P-123 exhibited the largest hydrophobic chain segment proportion (propylene oxide/ethylene oxide=3.63) and formed a brush chain conformation, indicating excellent protein and platelet resistance. The result of quartz crystal microbalance with dissipation further confirmed that the PEO conformation in P-123 on the substrate exhibited a relatively extended brush chain, and that L-35 showed relatively loose and pancake-like structures. The PEO in P-123 regulated the conformation to maintain the native conformation and resist the adsorption of bovine serum albumin (BSA). Thus, the hemocompatibilities of the immobilized Pluronics were influenced by the proportion of hydrophobic chain segments and their PEO conformations.

  7. Electrochemical quartz crystal microbalance studies on enzymatic specific activity and direct electrochemistry of immobilized glucose oxidase in the presence of sodium dodecyl benzene sulfonate and multiwalled carbon nanotubes.

    PubMed

    Su, Yuhua; Xie, Qingji; Chen, Chao; Zhang, Qingfang; Ma, Ming; Yao, Shouzhuo

    2008-01-01

    The electrochemical quartz crystal microbalance (EQCM) technique was utilized to monitor in situ the adsorption of glucose oxidase (GOD) and the mixture of GOD and sodium dodecyl benzene sulfonate (SDBS) onto Au electrodes with and without modification of multiwalled carbon nanotubes (MWCNTs) or SDBS/MWCNTs composite, and the relationship between enzymatic specific activity (ESA) and direct electrochemistry of the immobilized GOD was quantitatively evaluated for the first time. Compared with the bare gold electrode at which a little GOD was adsorbed and the direct electrochemistry of the adsorbed GOD was negligible, the amount and electroactivity of adsorbed GOD were greatly enhanced when the GOD was mixed with SDBS and then adsorbed onto the SDBS/MWCNTs modified Au electrode. However, the ESA of the adsorbed GOD was fiercely decreased to only 16.1% of the value obtained on the bare gold electrode, and the portion of adsorbed GOD showing electrochemical activity exhibited very low enzymatic activity, demonstrating that the electroactivity and ESA of immobilized GOD responded oppositely to the presence of MWCNTs and SDBS. The ESA results obtained from the EQCM method were well supported by conventional UV-vis spectrophotometry. The direct electrochemistry of redox proteins including enzymes as a function of their biological activities is an important concern in biotechnology, and this work may have presented a new and useful protocol to quantitatively evaluate both the electroactivity and ESA of trace immobilized enzymes, which is expected to find wider applications in biocatalysis and biosensing fields.

  8. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis

    NASA Astrophysics Data System (ADS)

    Petkova, Galina A.; Záruba, Кamil; Žvátora, Pavel; Král, Vladimír

    2012-06-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective ( ee > 99%) synthesis of ( S)-7-hydroxy-2-tetralol.

  9. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis

    PubMed Central

    2012-01-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective (ee > 99%) synthesis of (S)-7-hydroxy-2-tetralol. PMID:22655978

  10. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis.

    PubMed

    Petkova, Galina A; Záruba, Capital Ka Cyrillicamil; Zvátora, Pavel; Král, Vladimír

    2012-06-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective (ee > 99%) synthesis of (S)-7-hydroxy-2-tetralol.

  11. Immobilization of enzyme on a polymer surface

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Cheng, Kenneth Chun Kuen; Schroeder, McKenna; Yang, Pei; Marsh, E. Neil G.; Lahann, Joerg; Chen, Zhan

    2016-06-01

    We successfully immobilized enzymes onto polymer surfaces via covalent bonds between cysteine groups of the enzyme and dibromomaleimide functionalities present at the polymer surface. In this work, we used nitroreductase (NfsB) as a model enzyme molecule. The polymers were prepared by chemical vapor deposition (CVD) polymerization, resulting in surfaces with dibromomaleimide groups. NfsB variants were engineered so that each NfsB molecule only has one cysteine group on the enzyme surface. Two different NfsB constructs were studied, with cysteines at the positions of H360 and V424, respectively. A combination of sum frequency generation (SFG) vibrational and attenuated total reflectance Fourier transformed infrared (ATR-FTIR) spectroscopies were used to deduce the orientation of the immobilized enzymes on the surface. It was found that the orientation of the immobilized enzymes is controlled by the position of the cysteine residue in the protein. The NfsB H360C construct exhibited a similar orientational behavior on the polymer surface as compared to that on the self-assembled monolayer surface, but the NsfB V424C construct showed markedly different orientations on the two surfaces.

  12. Pentachlorophenol mineralization in an immobilized soil bioreactor

    SciTech Connect

    Karamanev, D.; Chavarie, C.; Samson, R.

    1996-12-31

    The biological degradation of pentachlorophenol (PCP) was conducted in a new type of reactor-the immobilized soil bioreactor. In this bioreactor soil particles having natural microbial activity in degrading the target pollutant are entrapped into a solid membrane with a large pore size distribution. The resulting {open_quotes}immobilized soil{close_quotes} system can be easily supplied with dissolved mineral salts, oxygen and target pollutant and as a result an active microbial consortium will be quickly established. This consortium is later used for treatment of aqueous solutions of the pollutant, for instance, contaminated ground water. We have studied the process of PCP biodegradation in both batch and continuous regime. our results showed that the volumetric effectiveness of the process of PCP mineralization in the immobilized soil bioreactor is between 7 and 4000 times higher than results reported in the literature. It has been found that both chlorine and carbon atoms of PCP are at least 99% mineralized. 7 refs., 4 figs., 1 tab.

  13. Effect of limb immobilization on skeletal muscle

    NASA Technical Reports Server (NTRS)

    Booth, F. W.

    1982-01-01

    Current knowledge and questions remaining concerning the effects of limb immobilization on skeletal muscle is reviewed. The most dramatic of these effects is muscle atrophy, which has been noted in cases of muscles fixed at or below their resting length. Immobilization is also accompanied by a substantial decrease in motoneuronal discharges, which results in the conversion of slow-twitch muscle to muscle with fast-twitch characteristics. Sarcolemma effects include no change or a decrease in resting membrane potential, the appearance of extrajunctional acetylcholine receptors, and no change in acetylcholinesterase activity. Evidence of changes in motoneuron after hyperpolarization characteristics suggests that the muscle inactivity is responsible for neuronal changes, rather than vice versa. The rate of protein loss from atrophying muscles is determined solely by the first-order rate constant for degradation. Various other biochemical and functional changes have been noted, including decreased insulin responsiveness and protein synthesis. The model of limb immobilization may also be useful for related studies of muscle adaptation.

  14. Immobilization of arginase and its application in an enzymatic chromatographic column: thermodynamic studies of nor-NOHA/arginase binding and role of the reactive histidine residue.

    PubMed

    Bagnost, Teddy; Guillaume, Yves-Claude; Thomassin, Mireille; Robert, Jean-François; Berthelot, Alain; Xicluna, Alain; André, Claire

    2007-09-01

    A biochromatographic approach is developed to measure for the first time changes in enthalpy, heat capacity change and protonation for the binding of nor-NOHA to arginase in a wide temperature range. For this, the arginase enzyme was immobilized on a chromatographic support. It was established that this novel arginase column was stable during an extended period of time. The affinity of nor-NOHA to arginase is high and changes slightly with the pH, because the number of protons linked to binding is low. The determination of the enthalpy change at different pH values suggested that the protonated group in the nor-NOHA-arginase complex exhibits a heat protonation of approximately -33 kJ/mol. This value agrees with the protonation of an imidazole group. Our result confirmed that active-site residue Hist 141 is protonated as imidazolium cation. Hist 141 can function as a general acid to protonate the leaving amino group of L-ornithine during catalysis. The thermodynamic data showed that nor-NOHA-arginase binding, for low temperature (<15 degrees C), is enthalpically unfavourable and being dominated by a positive entropy change. This result suggests that dehydration at the binding interface and charge-charge interactions contribute to the nor-NOHA-arginase complex formation. The temperature dependence of the free energy of binding is weak because of the enthalpy-entropy compensation caused by a large heat capacity change, DeltaC(p)=-2.43 kJ/mol/K, of arginase. Above 15 degrees C, the thermodynamic data DeltaH and DeltaS became negative due to van der Waals interactions and hydrogen bonding which are engaged at the complex interface confirming strong enzyme-inhibitor hydrogen bond networks. As well, by the use of these thermodynamic data and known correlations it was clearly demonstrated that the binding of nor-NOHA to arginase produces slight conformational changes in the vicinity of the active site. Our work indicated that our biochromatographic approach could soon

  15. Antibody immobilization on a nanoporous aluminum surface for immunosensor development

    NASA Astrophysics Data System (ADS)

    Chai, Changhoon; Lee, Jooyoung; Park, Jiyong; Takhistov, Paul

    2012-12-01

    A method of antibody (Ab) immobilization on a nanoporous aluminum surface for an electrochemical immunosensor is presented. To achieve good attachment and stability of Ab on an aluminum surface, aluminum was silanized with 3-aminopropyltryethoxysilane (APTES), and then covalently cross-linked to self-assembled layers (SALs) of APTES. Both the APTES concentration and the silanization time affected the formation of APTES-SALs as Ab immobilization. The formation of APTES-SALs was confirmed using the water contact angle on the APTES-SALs surface. The reactivity of APTES-SALs with Ab was investigated by measuring the fluorescence intensity of fluorescein isothiocyanate-labeled Ab-immobilized on the aluminum surface. Silanization of aluminum in 2% APTES for 4 h resulted in higher water contact angles and greater amounts of immobilized Ab than other APTES concentrations or silanization times. More Ab was immobilized on the nanoporous surface than on a planar aluminum surface. Electrochemical immunosensors developed on the nanoporous aluminum via the Ab immobilization method established in this study responded functionally to the antigen concentration in the diagnostic solution.

  16. Immobilization of pectin depolymerising polygalacturonase using different polymers.

    PubMed

    Ur Rehman, Haneef; Aman, Afsheen; Nawaz, Muhammad Asif; Karim, Asad; Ghani, Maria; Baloch, Abdul Hameed; Ul Qader, Shah Ali

    2016-01-01

    Polygalacturonase catalyses the hydrolysis of pectin substances and widely has been used in food and textile industries. In current study, different polymers such as calcium alginate beads, polyacrylamide gel and agar-agar matrix were screened for the immobilization of polygalacturonase through entrapment technique. Polyacrylamide gel was found to be most promising one and gave maximum (89%) immobilization yield as compared to agar-agar (80%) and calcium alginate beads (46%). The polymers increased the reaction time of polygalacturonase and polymers entrapped polygalacturonases showed maximum pectinolytic activity after 10 min of reaction as compared to free polygalacturonase which performed maximum activity after 5.0 min of reaction time. The temperature of polygalacturonase for maximum enzymatic activity was increased from 45°C to 50°C and 55°C when it was immobilized within agar-agar and calcium alginate beads, respectively. The optimum pH (pH 10) of polygalacturonase was remained same when it was immobilized within polyacrylamide gel and calcium alginate beads, but changed from pH 10 to pH 9.0 after entrapment within agar-agar. Thermal stability of polygalacturonase was improved after immobilization and immobilized polygalacturonases showed higher tolerance against different temperatures as compared to free enzyme. Polymers entrapped polygalacturonases showed good reusability and retained more than 80% of their initial activity during 2nd cycles.

  17. New immobilized cell system with protection against toxic solvents

    SciTech Connect

    Tanaka, H.; Harada, S.; Kurosawa, H.; Yajima, M.

    1987-01-01

    A new immobilized cell system providing protection against toxic solvents was investigated so that normal fermentations could be carried out in a medium containing toxic solvents. The system consists of immobilized growing cells in Ca-alginate gel beads to which vegetable oils, which are inexpensive absorbents of solvents, had been added. The ethanol fermentation of Saccharomyces cerevisiae ATCC 26603 was used as a model fermentation to study the protection afforded by the system against solvent toxicities. The fermentation was inhibited by solvents such as 2-octanol, benzene, toluene, and phenol. Ethanol production of one batch was not finished even after 35 h using immobilized growing yeast cells in conventional Ca-alginate gel beads in an ethanol production medium (5% glucose) containing 0.1% 2-octanol, which is used as a solvent for liquid-liquid extraction and is one of the most toxic solvents in our experiments. With the new immobilized growing cell system using vegetable oils, however, four repeated batch fermentations were completed in 35 h. Castor oil provided even more protection than soy bean, olive, and tung oils, and it was possible to complete six repeated batches in 35 h. The immobilized cell system with vegetable oils also provided protection against other toxic solvents such as benzene and toluene. A possible mechanism for the protective function of the new immobilized cell system is discussed.

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

    PubMed Central

    Handayani, Nurrahmi; Loos, Katja; Wahyuningrum, Deana; Buchari; 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 (PES–NH2) were successfully synthesized as novel materials for immobilization. Membranes with various pore sizes (from 10–600 nm) based on synthesized PES and PES–NH2 polymers were successfully fabricated to be applied as bioreactors to increase the immobilized lipase performances. The influence of pore sizes, concentration of additives, and the functional groups that are attached on the PES backbone on enzyme loading and enzyme activity was studied. The largest enzyme loading was obtained by Mucor miehei lipase immobilized onto a PES–NH2 membrane composed of 10% of PES–NH2, 8% of dibutyl phthalate (DBP), and 5% of polyethylene glycol (PEG) (872.62 µg/cm2). Hydrolytic activity of the immobilized lipases indicated that the activities of biocatalysts are not significantly decreased by immobilization. From the reusability test, the lipase immobilized onto PES–NH2 showed a better constancy than the lipase immobilized onto PES (the percent recovery of the activity of the lipases immobilized onto PES–NH2 and PES are 97.16% and 95.37%, respectively), which indicates that this novel material has the potential to be developed as a bioreactor for enzymatic reactions. PMID:24958172

  19. The Efficacy of the Rapid Form Cervical Vacuum Immobilizer in Cervical Spine Immobilization of the Equipped Football Player

    PubMed Central

    Ransone, Jack; Kersey, Robert; Walsh, Katie

    2000-01-01

    Objective: To determine the effectiveness of the Rapid Form Cervical Vacuum Immobilizer in controlling the cervical spine movements of a football player wearing shoulder pads and a helmet. Design and Setting: We used a 1-group, repeated-measures experimental design to radiographically assess cervical spine range of motion with and without the Rapid Form Cervical Vacuum Immobilizer. Two experimental conditions (with and without vacuum splint) were applied to 10 subjects in a repeated-measures design. Each subject was radiographed in cervical forward flexion, extension, and lateral flexion under each experimental condition. Subjects: Ten healthy male subjects without a history of cervical spine pathology or abnormality volunteered for this study. Measurements: Cervical forward flexion, extension, and lateral flexion range of motion were compared under both treatment conditions. Joint angles were determined by straightedge tangential lines drawn on the radiographs along the foramen magnum, inferior ring border of the atlas, and along the inferior tips of the 2nd through 7th vertebral bodies. The total range of motion was determined and compared with the treatment condition by multiple paired t tests. Results: The Cervical Vacuum Immobilizer limited cervical spine range of motion in forward flexion, extension, and lateral flexion. The secondary statistical analysis for the effect size determined that each group had a large effect size, indicating that the power of the experimental or vacuum splint group was high. Conclusions: We found that the Cervical Vacuum Immobilizer limited cervical spine range of motion in forward flexion, extension, and lateral flexion. The Cervical Vacuum Immobilizer can be easily placed on an injured, fully equipped football player and serves to limit cervical spine range of motion while the athlete is immobilized and transported. Future research should determine how the Cervical Vacuum Immobilizer limits range of motion with the athlete

  20. Bioluminescent Reaction by Immobilized Luciferase

    NASA Astrophysics Data System (ADS)

    Tanaka, Ryuta; Takahama, Eriko; Iinuma, Masataka; Ikeda, Takeshi; Kadoya, Yutaka; Kuroda, Akio

    We have investigated an effect of immobilization of luciferase molecules at the optical fiber end on a bioluminescent reaction. The time dependence of measured count rates of emitted photons has been analyzed by fitting with numerical solution of differential equations including the effect of the product-inhibitor and the deactivation of the luciferase. Through the analysis, we have successfully extracted kinetic constants such as, reaction rate, number of active luciferase molecules, etc. Ratio of active molecules to total luciferase molecules in immobilization was one order of magnitude lower than that in solution. The reaction rate of the bioluminescent process was also different from the one of free luciferase in solution.

  1. Hydrolysis of triacetin catalyzed by immobilized lipases: effect of the immobilization protocol and experimental conditions on diacetin yield.

    PubMed

    Hernandez, Karel; Garcia-Verdugo, Eduardo; Porcar, Raul; Fernandez-Lafuente, Roberto

    2011-05-06

    The effect of the immobilization protocol and some experimental conditions (pH value and presence of acetonitrile) on the regioselective hydrolysis of triacetin to diacetin catalyzed by lipases has been studied. Lipase B from Candida antarctica (CALB) and lipase from Rhizomucor miehei (RML) were immobilized on Sepabeads (commercial available macroporous acrylic supports) activated with glutaraldehyde (covalent immobilization) or octadecyl groups (adsorption via interfacial activation). All the biocatalysts accumulated diacetin. Covalently immobilized RML was more active towards rac-methyl mandelate than the adsorbed RML. However, this covalent RML preparation presented the lowest activity towards triacetin. For this reason, this preparation was discarded as biocatalyst for this reaction. At pH 7, acyl migration occurred giving a mixture of 1,2 and 1,3 diacetin, but at pH 5.5, only 1,2 diacetin was produced. Yields were improved at acidic pH values and in the presence of 20% acetonitrile (to over 95%). RML immobilized on octadecyl Sepabeads was proposed as optimal preparation, mainly due to its higher specific activity. Each enzyme preparation presented very different properties. Moreover, changes in the reaction conditions affected the various immobilized enzymes in a different way.

  2. Biodiesel production from Jatropha oil catalyzed by immobilized Burkholderia cepacia lipase on modified attapulgite.

    PubMed

    You, Qinghong; Yin, Xiulian; Zhao, Yuping; Zhang, Yan

    2013-11-01

    Lipase from Burkholderia cepacia was immobilized on modified attapulgite by cross-linking reaction for biodiesel production with jatropha oil as feedstock. Effects of various factors on biodiesel production were studied by single-factor experiment. Results indicated that the best conditions for biodiesel preparation were: 10 g jatropha oil, 2.4 g methanol (molar ratio of oil to methanol is 1:6.6) being added at 3h intervals, 7 wt% water, 10 wt% immobilized lipase, temperature 35°C, and time 24h. Under these conditions, the maximum biodiesel yield reached 94%. The immobilized lipase retained 95% of its relative activity during the ten repeated batch reactions. The half-life time of the immobilized lipase is 731 h. Kinetics was studied and the Vmax of the immobilized lipases were 6.823 mmol L(-1). This immobilized lipase catalyzed process has potential industrial use for biodiesel production to replace chemical-catalyzed method.

  3. Development of a liquid chromatographic system with fluorescent detection for beta-secretase immobilized enzyme reactor on-line enzymatic studies.

    PubMed

    Mancini, Francesca; Andrisano, Vincenza

    2010-07-08

    A novel liquid chromatographic method has been developed for use in throughput screening of new inhibitors of human recombinant beta-amyloid precursor protein cleaving enzyme (hrBACE1). The approach is based on the use of an immobilized enzyme reactor (IMER) containing the target enzyme (hrBACE1-IMER) and uses fluorescence detection. The bioreactor was prepared by immobilizing hrBACE1 on an ethylendiamine (EDA) monolithic disk (CIM) and a fluorogenic peptide (M-2420) containing the beta-secretase site of the Swedish mutation of amyloid precursor protein (APP) was used as substrate. After injection into the hrBACE1-IMER system, M-2420 was enzymatically cleaved, giving rise to a fluorescent methoxycoumaryl-fragment (Rt=1.6min), which was separated from the substrate and selectively detected at lambda(exc)=320 and lambda(em)=420nm. Product and substrate were characterized by using a post monolithic C18 stationary phase coupled to an ion trap mass analyser. A calibration curve was constructed to determine the immobilized hrBACE1-IMER rate of catalysis and kinetic constants. Specificity of the enzymatic cleavage was confirmed by injecting the substrate on a blank CIM-EDA. The proposed method was validated by the determination of the inhibitory potency of five reference compounds with activities ranked over four order of magnitude (four peptidic inhibitors and a green tea polyphenol, (-)gallocatechin gallate). The obtained results were found in agreement with the data reported in literature, confirming the validity and the applicability of the hrBACE1-IMER as a tool for the fast screening of unknown inhibitors (more than 6 compounds per hour). Moreover, the hrBACE1-IMER showed high stability during the analysis, permitting its use for more than three months without affecting enzyme activity.

  4. Radiation immobilization of catalase and its application

    NASA Astrophysics Data System (ADS)

    Guanghui, Wang; Hongfei, Ha; Xia, Wang; Jilan, Wu

    Catalase was immobilized by chemical method on porous polyacrylamide particles which produced through radiation polymerization of acrylamide monomer at low temperature (-78°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 2O 2 both in aqueous solution and alcoholic solution by using the immobilized catalase was performed.

  5. Graphene oxide immobilized enzymes show high thermal and solvent stability

    NASA Astrophysics Data System (ADS)

    Hermanová, Soňa; Zarevúcká, Marie; Bouša, Daniel; Pumera, Martin; Sofer, Zdeněk

    2015-03-01

    The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed lipase achieved over 100% of the initial activity in a series of organic solvents. These findings, showing enhanced thermal stability and solvent tolerance of graphene oxide immobilized enzyme, will have a profound impact on practical industrial scale uses of enzymes for the conversion of lipids into fuels.The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed

  6. Role of immobilization of irradiated rats in the protective effect of bone marrow shielding

    NASA Technical Reports Server (NTRS)

    Gronskaya, N. F.; Strelin, G. S.

    1982-01-01

    Rats were exposed to X-radiation to study the influence of immobilization and shielding of part of bone marrow during exposure on survival. It is concluded that (1) the beneficial effect of the stress factor (created by the immobilization of rats during exposure) can aggregate with the effect of bone marrow shielding and, under certain conditions, imitate the latter; and (2) the probability of the protective effect of immobilization should be taken into account when assessing the influence of bone marrow shielding.

  7. Effects of immobilization on articular cartilage: Autohistoradiographic findings with S35

    NASA Technical Reports Server (NTRS)

    Digiovanni, C.; Desantis, E.

    1980-01-01

    The effect of immobilization on the articular cartilage of rabbits was studied by light microscope. The knee joint of each rabbit was immobilized in a plaster in a position midway between flexion and extension for a 10 to 120 days period. Degenerative changes in the articular cartilage of increasing severity were observed. The fixation of the labeled SO4 by cartilage cells was decreased in advanced immobilization.

  8. Evaluation of immobilized enzymes for industrial applications.

    PubMed

    Liese, Andreas; Hilterhaus, Lutz

    2013-08-07

    In contrast to the application of soluble enzymes in industry, immobilized enzymes often offer advantages in view of stability, volume specific biocatalyst loading, recyclability as well as simplified downstream processing. In this tutorial review the focus is set on the evaluation of immobilized enzymes in respect to mass transport limitations, immobilization yield and stability, to enable industrial applications.

  9. Preparation, characterization, and luminescence of (SBA-15) immobilized pepsin

    NASA Astrophysics Data System (ADS)

    Zhai, Qing-Zhou; Sun, Si-Jia

    2014-12-01

    SBA-15 mesoporous silica was synthesized by hydrothermal method and its surface was methylated by treatment with methyltrimethoxysilane. Pepsin was immobilized on the obtained materials giving host-guest composite materials (SBA-15)-pepsin and (methylated SBA-15)-pepsin. The optimum conditions for preparation of these materials were established. Methylated SBA-15 (M-SBA-15) has improved immobilization efficiency of enzyme compared to initial SBA-15 silica. It was shown that with the gradual increase of NaCl solution ionic strength the immobilized amount of enzyme was reduced. Powder X-ray diffraction and Fourier transform infrared spectroscopy showed that the host frameworks in the prepared host-guest composite materials are intact and the ordered structure was retained. Scanning electron microscopic studies revealed fibrous morphologic characteristics of the SBA-15 and the immobilized pepsin composite materials. The average particle diameter of (SBA-15)-pepsin composite was 338 ± 10 and 343 ± 10 nm for (M-SBA-15)-pepsin. The low temperature N2 adsorption-desorption study at 77 K showed that the pore sizes and specific surface areas of the host-guest composite materials were smaller than those before the introduction of the enzyme, suggesting that the immobilized enzyme occupied a definite position in the host material pore channels. The UV-vis solid diffuse reflectance and luminescence studies showed that the enzyme was successfully immobilized on to the host material and that after the immobilization of enzyme on SBA-15 the conformation of pepsin macromolecule has not been changed.

  10. [Gel immobilization of human genome].

    PubMed

    Pan, Yingqiu; Zhang, Wei; Chen, Shuqing

    2013-01-01

    To develop a solid phase PCR method by covalent single point immobilization for recycle utilization of human genome. Polymethacrylamide gel was selected as a solid PCR carrier based on DNA-hydrogel copolymer chemistry presented by Mirzabekov. (CH2)6NH2 amino-modified PCR product and randomly fractured formic acid-modified plasmid pGEM-T-HLA-G were used as templates. The specificity of the attachment chemistry was characterized by acrylamide gel electrophoresis, and the thermal stability of method was demonstrated by PCR. This method was applied for the recycle utilization of human genome. Sequencing was used to exclude the possibility of introduced mutations during modification and immobilization procedures. The PCR detections of plasmid DNA and human genome DNA immobilized by polymethacrylamide gel was successful. The thermal stability of method was successfully demonstrated by performing PCR after 16 rounds of standard 36 PCR cycles. And the sequencing was found no mutation. The DNA immobilization method with polymethacrylamide gel as a solid phase carrier is stable and specific, which can be a possible approach for realizing recycle utilization of human genome for whole-genome sequencing and SNP detection.

  11. Immobilized yeast for alcohol production

    SciTech Connect

    Not Available

    1982-02-03

    Construction of a pilot alcohol plant has been completed in Japan to test a new idea in fermentation that could cut the time required from three or four days to several hours. According to developers, the key is an unidentified radiation-cured polymer that is used to immobilize yeast, permitting the process to run continuously.

  12. The application of immobilized biocatalyzers to intensify the ethanol fermentation of lactose.

    PubMed

    Lewandowska, M; Bednarski, W; Adamczak, M; Narwojsz, D

    2003-01-01

    Ethanol fermentation of lactose mash by biocatalyzers immobilized in sodium alginate was studied in order to improve the process productivity and economy. The fermentation effectiveness of S.cerevisiae co-immobilized with a p-galactosidase and the directly lactose- fermenting immobilized yeast: K. fragilis and C. pseudotropicalis were compared The application of the immobilized K. fragilis produced desirable results and even after its 9th (18 days) fermentation, the immobilized yeast provided the stable high fermentation level (on average about 6 ralvol of ethano/) while maintaining its activity. Such lactose-mash fermentation was greater than in conventional method (by free cells). In addition, the application of s. cerevisiae co-immobilized with p-galactosidase produced somewhat greater ferm levels than the conventional method, however, the system stability deteriorated after 6 days of fermentation.

  13. Enzyme immobilization and biocatalysis of polysiloxanes

    NASA Astrophysics Data System (ADS)

    Poojari, Yadagiri

    Lipases have been proven to be versatile and efficient biocatalysts which can be used in a broad variety of esterification, transesterification, and ester hydrolysis reactions. Due to the high chemo-, regio-, and stereo-selectivity and the mild conditions of lipase-catalyzed reactions, the vast potential of these biocatalysts for use in industrial applications has been increasingly recognized. Polysiloxanes (silicones) are well known for their unique physico-chemical properties and can be prepared in the form of fluids, elastomers, gels and resins for a wide variety of applications. However, the enzymatic synthesis of silicone polyesters and copolymers is largely unexplored. In the present investigations, an immobilized Candida antarctica lipase B (CALB) on macroporous acrylic resin beads (Novozym-435 RTM) has been successfully employed as a catalyst to synthesize silicone polyesters and copolymers under mild reaction conditions. The silicone aliphatic polyesters and the poly(dimethylsiloxane)--poly(ethylene glycol) (PDMS-PEG) copolymers were synthesized in the bulk (without using a solvent), while the silicone aromatic polyesters, the silicone aromatic polyamides and the poly(epsilon-caprolactone)--poly(dimethylsiloxane)--poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers were synthesized in toluene. The synthesized silicone polyesters and copolymers were characterized by Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). This dissertation also describes a methodology for physical immobilization of the enzyme pepsin from Porcine stomach mucosa in silicone elastomers utilizing condensation-cure room temperature vulcanization (RTV) of silanol-terminated poly(dimethylsiloxane) (PDMS). The activity and the stability of free pepsin and pepsin immobilized in silicone elastomers were studied with respect to p

  14. How to make inert boron nitride nanosheets active for the immobilization of polysulfides for lithium-sulfur batteries: a computational study.

    PubMed

    Zhao, Yuming; Yang, Le; Zhao, Jingxiang; Cai, Qinghhai; Jin, Peng

    2017-07-19

    The search for effective anchoring nanomaterials for the immobilization of soluble lithium polysulfide (Li2Sn) species to suppress their shuttling effect has been a key scientific issue for the large-scale practical application of lithium-sulfur (Li-S) batteries. In this work, by means of comprehensive density functional theory (DFT) computations, we systematically investigated the potential of a series of doped and defective boron nitride (BN) nanosheets as chemical immobilizers for the soluble Li2Sn species. Our results revealed that the introduction of dopants and defects can enhance the binding strength of Li2Sn species with BN nanosheets due to the strong LiN or SB interaction. In particular, the doped BN nanosheets that can moderately interact with Li2Sn species are shown to exhibit outstanding anchoring effects for Li-S batteries because they can keep a balance between the binding strength and integrity of Li2Sn species. Therefore, by carefully controlling the type of dopants, the inert BN nanosheet can be converted to quite a promising electrode material with high efficiency for Li-S batteries.

  15. Immobilization of type-I collagen and basic fibroblast growth factor (bFGF) onto poly (HEMA-co-MMA) hydrogel surface and its cytotoxicity study.

    PubMed

    Yan, Tuo; Sun, Rong; Li, Chun; Tan, Baihua; Mao, Xuan; Ao, Ningjian

    2010-08-01

    Type-I collagen and bFGF were immobilized onto the surface of poly (HEMA-co-MMA) hydrogel by grafting and coating methods to improve its cytotoxicity. The multi-layered structure of the biocompatible layer was confirmed by FTIR, AFM and static water contact angles. The layers were stable in body-like environment (pH 7.4). Human skin fibroblast cells (HSFC) were seeded onto Col/bFGF-poly (HEMA-co-MMA), Col-poly (HEMA-co-MMA) and poly (HEMA-co-MMA) films for 1, 3 and 5 day. MTT assay was performed to evaluate the extraction toxicity of the materials. Results showed that the cell attachment, proliferation and differentiation on Col/bFGF-poly (HEMA-co-MMA) film were higher than those of the control group, which indicated the improvement of cell-material interaction. The extraction toxicity of the modified materials was also lower than that of the unmodified group. The protein and bFGF immobilized poly (HEMA-co-MMA) hydrogel might hold great promise to be a biocompatible material.

  16. Impact of age, injury severity score, and medical comorbidities on early complications after fusion and halo-vest immobilization for C2 fractures in older adults: a propensity score matched retrospective cohort study.

    PubMed

    Boakye, Maxwell; Arrigo, Robert T; Kalanithi, Paul S A; Chen, Yi-Ren

    2012-05-01

    Propensity score matched retrospective cohort study. To report early complication rates and associated risk factors in patients with C2 fractures who underwent fusion or halo immobilization. There is limited data on the impact of age, injury severity score, and medical comorbidities on overall complication rates from surgical fixation versus halo-vest immobilization of C2 fractures. The Nationwide Inpatient Sample database from 2002 to 2008 was queried to identify cohorts of adult patients (age ≥ 18 years) with C2 fractures without spinal cord injury who were treated with either fusion or halo-vest immobilization. Complication rates, hospital length of stay, and costs were compared in a propensity score matched sample. Multivariate analysis was used to identify predictors of in-hospital complications. A total of 3758 patients (1627 fusion and 2131 halo) were identified. Fusion was associated with greater overall complication rates (20.2% vs. 10.1%, P < 0.0001), increased length of stay (8.9 d vs. 6.4 d, P < 0.0001), higher charges ($80,000 vs. $41,000, P < 0.0001), but a lower rate of nonroutine discharge (52.6% vs. 62.6%, P < 0.0001). There was no difference in mortality between the fusion group (2.75%) and the halo group (3.33%). Age, injury score, and comorbidity increased complication rates by a similar degree (odds ratio) in both cohorts. Patients aged 80 years and older were 3.5 times more likely to have a complication than those younger than 60 years. Fusion patients had greater overall complication rates, increased length of stay, and greater resource utilization but were discharged home in a greater proportion. Both fusion and halo were associated with significant (more than 3-fold) increase in complication rates in elderly patients aged 80 years or older. Given the similar mortality rate between the fusion group and the halo group and the higher cost and complication rate in the fusion group, our study supports the use of halo-vest immobilization in

  17. Mineral induction by immobilized phosphoproteins

    NASA Technical Reports Server (NTRS)

    Saito, T.; Arsenault, A. L.; Yamauchi, M.; Kuboki, Y.; Crenshaw, M. A.

    1997-01-01

    Dentin phosphoproteins are thought to have a primary role in the deposition of mineral on the collagen of dentin. In this study we determined the type of binding between collagen and phosphoproteins necessary for mineral formation onto collagen fibrils and whether the phosphate esters are required. Bovine dentin phosphophoryn or phosvitin from egg yolk were immobilized on reconstituted skin type I collagen fibrils by adsorption or by covalent cross-linking. In some samples the ester phosphate was removed from the covalently cross-linked phosphoproteins by treatment with acid phosphatase. All samples were incubated at 37 degrees C in metastable solutions that do not spontaneously precipitate. Reconstituted collagen fibrils alone did not induce mineral formation. The phosphoproteins adsorbed to the collagen fibrils desorbed when the mineralization medium was added, and mineral was not induced. The mineral induced by the cross-linked phosphoproteins was apatite, and the crystals were confined to the surface of the collagen fibrils. With decreasing medium saturation the time required for mineral induction increased. The interfacial tensions calculated for apatite formation by either phosphoprotein cross-linked to collagen were about the same as that for phosphatidic acid liposomes and hydroxyapatite. This similarity in values indicates that the nucleation potential of these highly phosphorylated surfaces is about the same. It is concluded that phosphoproteins must be irreversibly bound to collagen fibrils for the mineralization of the collagen network in solutions that do not spontaneously precipitate. The phosphate esters of phosphoproteins are required for mineral induction, and the carboxylate groups are not sufficient.

  18. Mineral induction by immobilized phosphoproteins

    NASA Technical Reports Server (NTRS)

    Saito, T.; Arsenault, A. L.; Yamauchi, M.; Kuboki, Y.; Crenshaw, M. A.

    1997-01-01

    Dentin phosphoproteins are thought to have a primary role in the deposition of mineral on the collagen of dentin. In this study we determined the type of binding between collagen and phosphoproteins necessary for mineral formation onto collagen fibrils and whether the phosphate esters are required. Bovine dentin phosphophoryn or phosvitin from egg yolk were immobilized on reconstituted skin type I collagen fibrils by adsorption or by covalent cross-linking. In some samples the ester phosphate was removed from the covalently cross-linked phosphoproteins by treatment with acid phosphatase. All samples were incubated at 37 degrees C in metastable solutions that do not spontaneously precipitate. Reconstituted collagen fibrils alone did not induce mineral formation. The phosphoproteins adsorbed to the collagen fibrils desorbed when the mineralization medium was added, and mineral was not induced. The mineral induced by the cross-linked phosphoproteins was apatite, and the crystals were confined to the surface of the collagen fibrils. With decreasing medium saturation the time required for mineral induction increased. The interfacial tensions calculated for apatite formation by either phosphoprotein cross-linked to collagen were about the same as that for phosphatidic acid liposomes and hydroxyapatite. This similarity in values indicates that the nucleation potential of these highly phosphorylated surfaces is about the same. It is concluded that phosphoproteins must be irreversibly bound to collagen fibrils for the mineralization of the collagen network in solutions that do not spontaneously precipitate. The phosphate esters of phosphoproteins are required for mineral induction, and the carboxylate groups are not sufficient.

  19. DNA-directed immobilization of horseradish peroxidase onto porous SiO2 optical transducers

    NASA Astrophysics Data System (ADS)

    Shtenberg, Giorgi; Massad-Ivanir, Naama; Engin, Sinem; Sharon, Michal; Fruk, Ljiljana; Segal, Ester

    2012-08-01

    Multifunctional porous Si nanostructure is designed to optically monitor enzymatic activity of horseradish peroxidase. First, an oxidized PSi optical nanostructure, a Fabry-Pérot thin film, is synthesized and is used as the optical transducer element. Immobilization of the enzyme onto the nanostructure is performed through DNA-directed immobilization. Preliminary studies demonstrate high enzymatic activity levels of the immobilized horseradish peroxidase, while maintaining its specificity. The catalytic activity of the enzymes immobilized within the porous nanostructure is monitored in real time by reflective interferometric Fourier transform spectroscopy. We show that we can easily regenerate the surface for consecutive biosensing analysis by mild dehybridization conditions.

  20. Immobilization of Cr (VI) in stainless steel slag and Cd, As, and Pb in wastewater using blast furnace slag via a hydrothermal treatment

    NASA Astrophysics Data System (ADS)

    Tae, Soon-Jae; Morita, Kazuki

    2017-05-01

    The immobilization of hexavalent chromium in stainless steel slag using blast furnace slag as the immobilizing agent and by performing a hydrothermal treatment was investigated. The results showed that there was no immobilization in the absence of the blast furnace slag. On the other hand, the hexavalent chromium in stainless steel slag could be immobilized through the hydrothermal reaction when blast furnace slag was used at 250 °C for 24 h. A leaching test was performed to evaluate the degree of immobilization of hexavalent chromium in the products formed by the hydrothermal reaction. It was found that the degree of immobilization was very high. Based on the results obtained, the immobilization mechanism of hexavalent chromium in stainless steel slag, resulting from the hydrothermal treatment of blast furnace slag, could be elucidated. Finally, the immobilization of cadmium, lead, and arsenic using blast furnace slag as the immobilization agent was also studied while focusing on the effects of the hydrothermal treatment.

  1. Recent developments and applications of immobilized laccase.

    PubMed

    Fernández-Fernández, María; Sanromán, M Ángeles; Moldes, Diego

    2013-12-01

    Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry.

  2. Degradation of Carbazole by Microbial Cells Immobilized in Magnetic Gellan Gum Gel Beads▿

    PubMed Central

    Wang, Xia; Gai, Zhonghui; Yu, Bo; Feng, Jinhui; Xu, Changyong; Yuan, Yong; Lin, Zhixin; Xu, Ping

    2007-01-01

    Polycyclic aromatic heterocycles, such as carbazole, are environmental contaminants suspected of posing human health risks. In this study, we investigated the degradation of carbazole by immobilized Sphingomonas sp. strain XLDN2-5 cells. Four kinds of polymers were evaluated as immobilization supports for Sphingomonas sp. strain XLDN2-5. After comparison with agar, alginate, and κ-carrageenan, gellan gum was selected as the optimal immobilization support. Furthermore, Fe3O4 nanoparticles were prepared by a coprecipitation method, and the average particle size was about 20 nm with 49.65-electromagnetic-unit (emu) g−1 saturation magnetization. When the mixture of gellan gel and the Fe3O4 nanoparticles served as an immobilization support, the magnetically immobilized cells were prepared by an ionotropic method. The biodegradation experiments were carried out by employing free cells, nonmagnetically immobilized cells, and magnetically immobilized cells in aqueous phase. The results showed that the magnetically immobilized cells presented higher carbazole biodegradation activity than nonmagnetically immobilized cells and free cells. The highest biodegradation activity was obtained when the concentration of Fe3O4 nanoparticles was 9 mg ml−1 and the saturation magnetization of magnetically immobilized cells was 11.08 emu g−1. Additionally, the recycling experiments demonstrated that the degradation activity of magnetically immobilized cells increased gradually during the eight recycles. These results support developing efficient biocatalysts using magnetically immobilized cells and provide a promising technique for improving biocatalysts used in the biodegradation of not only carbazole, but also other hazardous organic compounds. PMID:17827304

  3. Biodiesel production with immobilized lipase: A review.

    PubMed

    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.

  4. Immobilized glycosylated Fmoc-amino acid for SPR: comparative studies of lectin-binding to linear or biantennary diLacNAc structures.

    PubMed

    Nakamura, Kosuke; Sakagami, Hiromi; Asanuma-Date, Kimie; Nagasawa, Nao; Nakahara, Yoshiaki; Akiyama, Hiroshi; Ogawa, Haruko

    2013-12-15

    A method to immobilize glycan-linked amino acids with protected α-amino groups, which are key intermediates to produce the desired neoglycoprotein, to a Biacore sensor chip was developed and its utility for interaction analyses was demonstrated. Two types of diN-acetyllactosamine (diLacNAc)-containing glycans, a core 2 hexasaccharide involving linear diLacNAc that is O-linked to N-(9-fluorenyl)methoxycarbonyl (Fmoc)-Thr and a biantennary diLacNAc that is N-linked to Fmoc-Asn, were used as ligands. For immobilization, the free carboxyl groups of the amino acid residues were activated with EDC/NHS, then reacted with the ethylenediamine-derivatized carboxymethyldextran sensor chip to obtain the desired ligand concentrations. Interactions of the ligands with five plant lectins were analyzed by surface plasmon resonance, and the bindings were compared. The resonance unit of each lectin was corrected by subtracting that of the reference cell on which the Fmoc-Thr-core 1 or Fmoc-Asn was immobilized as a ligand. The carbohydrate specificities of interactions were verified by preincubating lectins with their respective inhibitory sugar before injection. By steady state analysis, the Lycopersicon esculentum lectin showed a 27-fold higher affinity to linear diLacNAc than to biantennary diLacNAc, while Datura stramonium and Solanum tuberosum lectins both showed low Ka,apps of 10(6)M(-1) for these two ligands. In contrast, Ricinus communis agglutinin-120 showed a 3.2-fold higher Ka,app to biantennary LacNAc than to linear diLacNAc. A lectin purified from Pleurocybella porrigens mushroom interacted at the high affinity of 10(8)M(-1) with both linear and biantennary diLacNAcs, which identified it as a unique probe. This method provides a useful and sensitive system to analyze interactions by simulating the glycans on the cell surface. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Effects of acoustic wave resonance oscillation on immobilized enzyme

    NASA Astrophysics Data System (ADS)

    Nishiyama, Hiroshi; Watanabe, Tomoya; Inoue, Yasunobu

    2014-03-01

    In aiming at developing a new method to artificially activate enzyme catalysts immobilized on surface, the effects of resonance oscillation of bulk acoustic waves were studied. Glucose oxidase (GOD) was immobilized by a covalent coupling method on a ferroelectric lead zirconate titanate (PZT) device that was able to generate thickness-extensional resonance oscillation (TERO). Glucose oxidation by the GOD enzyme was studied in a microreactor. The generation of TERO immediately increased the catalytic activity of immobilized GOD by a factor of 2-3. With turn-off of TERO, no significant activity decrease occurred, and 80-90% of the enhanced activity was maintained while the reaction proceeded. The almost complete reversion of the activity to the original low level before TERO generation was observed when the immobilized GOD was exposed to a glucose substrate-free solution. These results indicated that the presence of glucose substrate was essential for TERO-induced GOD activation and preservation of the increased activity level. The influences of reaction temperature, glucose concentration, pH, and rf electric power on the TERO activation showed that TERO strengthened the interactions of the immobilized enzyme with glucose substrate and hence promoted the formation of an activation complex.

  6. Immobilization of diastase α-amylase on nano zinc oxide.

    PubMed

    Antony, Navya; Balachandran, S; Mohanan, P V

    2016-11-15

    Diastase α-amylase extracted from malt, catalyses break down of starch into maltose. It is commonly used in food and fermentation industry. In the present study nano zinc oxide is used as support for this starch hydrolyzing enzyme. IR study revealed that the enzyme got adsorbed via electrostatic interaction with the functional groups on the support. The immobilized enzyme possessed a better heat-resistance than free enzyme. The kinetic parameters were determined using Lineweaver-Burk plot. The immobilized enzyme showed higher Km 2.08mg/ml than the free enzyme whose Km is 0.45±.05mg/ml. The Vmax of immobilized enzyme was about 2.92±.02mg/ml/min and that of free enzyme was 7.14±.02mg/ml/min, showing decrease in activity after immobilization. The immobilized enzyme showed 70% activity after 30days of storage while free enzyme lost its activity within 7days. About 80% of enzyme retained activity after 4 cycles of reuse.

  7. Effect of membranes with various hydrophobic/hydrophilic properties on lipase immobilized activity and stability.

    PubMed

    Chen, Guan-Jie; Kuo, Chia-Hung; Chen, Chih-I; Yu, Chung-Cheng; Shieh, Chwen-Jen; Liu, Yung-Chuan

    2012-02-01

    In this study, three membranes: regenerated cellulose (RC), glass fiber (GF) and polyvinylidene fluoride (PVDF), were grafted with 1,4-diaminobutane (DA) and activated with glutaraldehyde (GA) for lipase covalent immobilization. The efficiencies of lipases immobilized on these membranes with different hydrophobic/hydrophilic properties were compared. The lipase immobilized on hydrophobic PVDF-DA-GA membrane exhibited more than an 11-fold increase in activity compared to its immobilization on a hydrophilic RC-DA-GA membrane. The relationship between surface hydrophobicity and immobilized efficiencies was investigated using hydrophobic/hydrophilic GF membranes which were prepared by grafting a different ratio of n-butylamine/1,4-diaminobutane (BA/DA). The immobilized lipase activity on the GF membrane increased with the increased BA/DA ratio. This means that lipase activity was exhibited more on the hydrophobic surface. Moreover, the modified PVDF-DA membrane was grafted with GA, epichlorohydrin (EPI) and cyanuric chloride (CC), respectively. The lipase immobilized on the PVDF-DA-EPI membrane displayed the highest specific activity compared to other membranes. This immobilized lipase exhibited more significant stability on pH, thermal, reuse, and storage than did the free enzyme. The results exhibited that the EPI modified PVDF is a promising support for lipase immobilization. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. Protein immobilization onto various surfaces using a polymer-bound isocyanate

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Jin; Cha, Eun Ji; Park, Hee-Deung

    2015-01-01

    Silane coupling agents have been widely used for immobilizing proteins onto inorganic surfaces. However, the immobilization method using silane coupling agents requires several treatment steps, and its application is limited to only surfaces containing hydroxyl groups. The aim of this study was to develop a novel method to overcome the limitations of the silane-based immobilization method using a polymer-bound isocyanate. Initially, polymer-bound isocyanate was dissolved in organic solvent and then was used to dip-coat inorganic surfaces. Proteins were then immobilized onto the dip-coated surfaces by the formation of urea bonds between the isocyanate groups of the polymer and the amine groups of the protein. The reaction was verified by FT-IR in which NCO stretching peaks disappeared, and CO and NH stretching peaks appeared after immobilization. The immobilization efficiency of the newly developed method was insensitive to reaction temperatures (4-50 °C), but the efficiency increased with reaction time and reached a maximum after 4 h. Furthermore, the method showed comparable immobilization efficiency to the silane-based immobilization method and was applicable to surfaces that cannot form hydroxyl groups. Taken together, the newly developed method provides a simple and efficient platform for immobilizing proteins onto surfaces.

  9. Comparative evaluation of pumice stone as an alternative immobilization material for 1,3-propanediol production from waste glycerol by immobilized Klebsiella pneumoniae.

    PubMed

    Gonen, Cagdas; Gungormusler, Mine; Azbar, Nuri

    2012-12-01

    In this study, pumice stone (PS), which is a vastly available material in Turkey, was evaluated as an alternative immobilization material in comparison to other commercially available immobilization materials such as glass beads and polyurethane foam. All immobilized bioreactors resulted in much better 1,3-propanediol production from waste glycerol in comparison to the suspended cell culture bioreactor. It was also demonstrated that the locally available PS material is as good as the commercially available immobilization material. The maximum volumetric productivity (8.5 g L(-1) h(-1)) was obtained by the PS material, which is 220 % higher than the suspended cell system. Furthermore, the immobilized bioreactor system was much more robust against cell washout even at very low hydraulic retention time values.

  10. Spectroscopic Evidence of Uranium Immobilization in Acidic ...

    EPA Pesticide Factsheets

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah River Site (SRS) wetland sediments under varying redox and acidic (pH = 2.6-5.8) conditions using U L3-edge X-ray absorption spectroscopy. Uranium in the SRS wetland sediments existed primarily as U(VI) bonded as a bidentate to carboxylic sites (U-C bond distance at ~2.88 Å), rather than phenolic or other sites of natural organic matter (NOM). In microcosms simulating the SRS wetland process, U immobilization on roots was 2 orders of magnitude higher than on the adjacent brown or more distant white sands in which U was U(VI). Uranium on the roots were both U(IV) and U(VI), which were bonded as a bidentate to carbon, but the U(VI) may also form a U phosphate mineral. After 140 days of air exposure, all U(IV) was reoxidized to U(VI) but remained as a bidentate bonding to carbon. This study demonstrated NOM and plant roots can highly immobilize U(VI) in the SRS acidic sediments, which has significant implication on the long-term stewardship of U-contaminated wetlands. There were several former U processing facilities at the Savannah River Site (SRS), Aiken, SC. As a result of their operations, uranium has entered the surrounding environments. For example, approximately 45,000 kg o

  11. Metal immobilization and soil amendment efficiency at a contaminated sediment landfill site: a field study focusing on plants, springtails, and bacteria.

    PubMed

    Bert, Valérie; Lors, Christine; Ponge, Jean-François; Caron, Lucie; Biaz, Asmaa; Dazy, Marc; Masfaraud, Jean-François

    2012-10-01

    Metal immobilization may contribute to the environmental management strategy of dredged sediment landfill sites contaminated by metals. In a field experiment, amendment effects and efficiency were investigated, focusing on plants, springtails and bacteria colonisation, metal extractability and sediment ecotoxicity. Conversely to hydroxylapatite (HA, 3% DW), the addition of Thomas Basic Slag (TBS, 5% DW) to a 5-yr deposited sediment contaminated with Zn, Cd, Cu, Pb and As resulted in a decrease in the 0.01 M Ca(NO(3))(2)-extractable concentrations of Cd and Zn. Shoot Cd and Zn concentration in Calamagrostis epigejos, the dominant plant species, also decreased in the presence of TBS. The addition of TBS and HA reduced sediment ecotoxicity and improved the growth of the total bacterial population. Hydroxylapatite improved plant species richness and diversity and decreased antioxidant enzymes in C. Epigejos and Urtica dïoica. Collembolan communities did not differ in abundance and diversity between the different treatments.

  12. A High-Resolution Magic Angle Spinning NMR Study of the Enantiodiscrimination of 3,4-Methylenedioxymethamphetamine (MDMA) by an Immobilized Polysaccharide-Based Chiral Phase

    PubMed Central

    Paixão, Márcio W.; Lourenço, Tiago C.

    2016-01-01

    This paper reports the investigation of the chiral interaction between 3,4-methylenedioxy-methamphetamine (MDMA) enantiomers and an immobilized polysaccharide-based chiral phase. For that, suspended-state high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (1H HR-MAS NMR) was used. 1H HR-MAS longitudinal relaxation time and Saturation Transfer Difference (STD NMR) titration experiments were carried out yielding information at the molecular level of the transient diastereoisomeric complexes of MDMA enantiomers and the chiral stationary phase. The interaction of the enantiomers takes place through the aromatic moiety of MDMA and the aromatic group of the chiral selector by π-π stacking for both enantiomers; however, a stronger interaction was observed for the (R)-enantiomer, which is the second one to elute at the chromatographic conditions. PMID:27668862

  13. Evaluation of an organo-layered double hydroxide and two organic residues as amendments to immobilize metalaxyl enantiomers in soils: A comparative study.

    PubMed

    López-Cabeza, Rocío; Cornejo, Juan; Celis, Rafael

    2016-10-01

    Many pollutants released into the environment as a result of human activities are chiral. Pollution control strategies generally consider chiral compounds as if they were achiral and rarely consider enantiomers separately. We compared the performance of three different materials, an organically-modified anionic clay (HT-ELA) and two organic agro-food residues (ALP and ALPc), as amendments to immobilize the chiral fungicide metalaxyl in two soils with different textures, addressing the effects of the amendments on the sorption, persistence, and leaching of each of the two enantiomers of metalaxyl (R-metalaxyl and S-metalaxyl) separately. The effects of the amendments were both soil- and amendment-dependent, as well as enantiomer-selective. The organo-clay (HT-ELA) was much more efficient in increasing the sorption capacity of the soils for the two enantiomers of metalaxyl than the agro-food residues (ALP and ALPc), even when applied at a reduced application rate. The enhanced sorption in HT-ELA-amended soils reduced the bioavailability of metalaxyl enantiomers and their leaching in the soils, mitigating the particularly high leaching potential of the more persistent S enantiomer. The immobilizing capacity of the agro-food residues was more variable, mainly because their addition did not greatly ameliorate the sorption capacity of the soils and had variable effects on the enantiomers degradation rates. HT-ELA showed potential to reduce the bioavailability and mobility of metalaxyl enantiomers in soil and to mitigate the contamination problems particularly associated with the higher leaching potential of the more persistent enantiomer. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Thermodynamic study of the interaction between terbutaline and salbutamol with an immobilized beta(2)-adrenoceptor by high-performance liquid chromatography.

    PubMed

    Zhao, Xinfeng; Zheng, Xiaohui; Wei, Yinmao; Bian, Liujiao; Wang, Shixiang; Zheng, Jianbin; Zhang, Youyi; Li, Zijian; Zang, Weijin

    2009-04-01

    Investigation of the interaction between drugs and receptors is very important in revealing the biologic basis and mechanism of the drug, and designing new bioactive compounds. The beta(2)-adrenoceptor (beta(2)-AR) was purified from rabbit lung tissues and immobilized on the surface of macro-pore silica gel through covalent bonds to prepare the stationary phase. Binding isotherms of terbutaline and salbutamol were determined by frontal analysis and the perturbation method, respectively. On the basis of the model of binding isotherm assumed, zonal elution was used to investigate the binding interaction of the receptor with terbutaline and salbutamol. The two drugs had one type of common binding site on immobilized beta(2)-AR. Salbutamol had at least one other major binding region. The association constant for terbutaline was (9.76+/-0.67)x10(4)/M, and the concentration of the binding sites was (9.37+/-1.32)x10(-6)M. Under identical conditions, association constants for salbutamol at the two types of binding site were (1.11+/-0.08)x10(4)/M and (1.34+/-0.13)x10(3)/M, and the concentration of the binding sites was (5.46+/-0.35)x10(-6)M. Entropy increase was the main driving force for terbutaline and salbutamol to bind with beta(2)-AR. The associating reaction of terbutaline and beta(2)-AR was an exothermal process primarily from electrostatic interactions; hydrophobic force was the major factor contributing to the process for salbutamol.

  15. Immobilization of iodine in concrete

    DOEpatents

    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.

  16. Effects of Vibration Therapy on Immobilization-Induced Hypersensitivity in Rats.

    PubMed

    Hamaue, Yohei; Nakano, Jiro; Sekino, Yuki; Chuganji, Sayaka; Sakamoto, Junya; Yoshimura, Toshiro; Okita, Minoru; Origuchi, Tomoki

    2015-07-01

    Cast immobilization induces mechanical hypersensitivity, which disturbs rehabilitation. Although vibration therapy can reduce various types of pain, whether vibration reduces immobilization-induced hypersensitivity remains unclear. The purpose of this study was to investigate the preventive and therapeutic effects of vibration therapy on immobilization-induced hypersensitivity. The experimental design of the study involved conducting behavioral, histological, and immunohistochemical studies in model rats. Thirty-five Wistar rats (8 weeks old, all male) were used. The right ankle joints of 30 rats were immobilized by plaster cast for 8 weeks, and 5 rats were used as controls. The immobilized rats were divided randomly into the following 3 groups: (1) immobilization-only group (Im, n=10); (2) vibration therapy group 1, for which vibration therapy was initiated immediately after the onset of immobilization (Im+Vib1, n=10); and (3) vibration therapy group 2, for which vibration therapy was initiated 4 weeks after the onset of immobilization (Im+Vib2, n=10). Vibration was applied to the hind paw. The mechanical hypersensitivity and epidermal thickness of the hind paw skin were measured. To investigate central sensitization, calcitonin gene-related peptide (CGRP) expression in the spinal cord and dorsal root ganglion (DRG) was analyzed. Immobilization-induced hypersensitivity was inhibited in the Im+Vib1 group but not in the Im+Vib2 group. Central sensitization, which was indicated by increases in CGRP expression in the spinal cord and the size of the area of CGRP-positive neurons in the DRG, was inhibited in only the Im+Vib1 group. Epidermal thickness was not affected by vibration stimulation. A limitation of this study is that the results were limited to an animal model and cannot be generalized to humans. The data suggest that initiation of vibration therapy in the early phase of immobilization may inhibit the development of immobilization-induced hypersensitivity.

  17. Algal polysaccharides as matrices for the immobilization of urease in lipid ultrathin films studied with tensiometry and vibrational spectroscopy: Physical-chemical properties and implications in the enzyme activity.

    PubMed

    de Brito, Audrey Kalinouski; Nordi, Cristina S F; Caseli, Luciano

    2015-11-01

    Currently, many biological substances extracted from algae have received special attention because of their intrinsic characteristics, which can be applied to different areas of biotechnology. Therefore, in the current study, exopolysaccharides (EPS) from the microalgae Cryptomonas tetrapirenoidosa were employed as an aqueous subphase of a monolayer formed by the lipid dioctadecyldimethylammonium bromide (DODAB). The primary objective of this approach was to evaluate whether EPS could serve as a matrix for the immobilization of the enzyme urease to produce biosensors for urea. After DODAB was spread on the EPS solutions, urease was injected into the aqueous subphase, and the surface was submitted to compression using lateral barriers. The monolayers were subsequently characterized by surface pressure-area isotherms and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). The results indicated that EPS enhanced the adsorption of the enzyme on the lipid monolayer. The mixed films were later transferred to solid supports using the Langmuir-Blodgett (LB) technique and were characterized by transfer ratio, PM-IRRAS, quartz crystal microbalance, and atomic force microscopy. The immobilization of the enzyme on solid supports was fundamental for providing an ideal geometrical accommodation of urease because the interaction of EPS with urease in solution causes a decrease of the relative activity of urease. Therefore, these LB films are promising for the fabrication of future urea biosensors, the architecture of which can be manipulated and enhanced at the molecular level.

  18. Activity stabilization of Aspergillus niger and Escherichia coli phytases immobilized on allophanic synthetic compounds and montmorillonite nanoclays.

    PubMed

    Menezes-Blackburn, Daniel; Jorquera, Milko; Gianfreda, Liliana; Rao, Maria; Greiner, Ralf; Garrido, Elizabeth; de la Luz Mora, María

    2011-10-01

    The aim of this work was to study the stabilization of the activity of two commercial microbial phytases (Aspergillus niger and Escherichia coli) after immobilization on nanoclays and to establish optimal conditions for their immobilization. Synthetic allophane, synthetic iron-coated allophanes and natural montmorillonite were chosen as solid supports for phytase immobilization. Phytase immobilization patterns at different pH values were strongly dependent on both enzyme and support characteristics. After immobilization, the residual activity of both phytases was higher under acidic conditions. Immobilization of phytases increased their thermal stability and improved resistance to proteolysis, particularly on iron-coated allophane (6% iron oxide), which showed activation energy (E(a)) and activation enthalpy (ΔH(#)) similar to free enzymes. Montmorillonite as well as allophanic synthetic compounds resulted in a good support for immobilization of E. coli phytase, but caused a severe reduction of A. niger phytase activity.

  19. [The release of immobilized substances from Symplex capsules].

    PubMed

    Götze, M; Torner, H; Kauffold, P; König, I; Dautzenberg, H; Loth, F

    1986-04-01

    A new procedure of microencapsulation was studied with regard to substance release and quantification of diffusion processes on the capsule membrane. The permeability behaviour on the capsule membrane was especially studied in metabolites, which are essential for immobilized biological objects (i.g. preimplantative mammal embryos). Peptide and proteohormones, cyanmethemoglobin and proteins were enclosed in simple and multiple Symplex Capsules. All substances examined are able to pass the Symplex membrane. The speed of release is influenced by the size of the capsule, the ion force, temperature, concentration of immobilized substances as well as their linear and globular structur. Compared with simple capsules the release of substances from multiple capsules was delayed. Corresponding to the results found under the experimental design described the Symplex membrane can be considered as coating for the compartmentation of cells, that allows the passage of essential substances for the immobilized objects. The method of microencapsulation used and described has various ways of application.

  20. Immobilization of glucosyltransferase from Erwinia sp. using two different techniques.

    PubMed

    Contesini, Fabiano Jares; Ibarguren, Carolina; Grosso, Carlos Raimundo Ferreira; Carvalho, Patrícia de Oliveira; Sato, Hélia Harumi

    2012-04-15

    Two different techniques of glucosyltransferase immobilization were studied for the conversion of sucrose into isomaltulose. The optimum conditions for immobilization of Erwinia sp. glucosyltransferase onto Celite 545, determined using response surface methodology, was pH 4.0 and 170 U of glucosyltransferase/g of Celite 545. Using this conditions more than 60% conversion of sucrose into isomaltulose can be obtained. The immobilization of glucosyltransferase was also studied by its entrapment in microcapsules of low-methoxyl pectin and fat (butter and oleic acid). The non-lyophilized microcapsules of pectin, containing the enzyme and fat, showed higher glucosyltransferase activity, compared with lyophilized microcapsules containing enzyme plus fat, and also lyophilized microcapsules containing enzyme without fat addition. The non-lyophilized microcapsules of pectin containing the glucosyltransferase and fat, converted 30% of sucrose into isomaltulose in the first batch. However the conversion decreased to 5% at the 10th batch, indicating inactivation of the enzyme.

  1. Immobilization of Yarrowia lipolytica for aroma production from castor oil.

    PubMed

    Braga, Adelaide; Belo, Isabel

    2013-04-01

    The main aim of this study was to compare different materials for Y. lipolytica immobilization that could be used in the production of γ-decalactone (a peach-like aroma) in order to prevent the toxic effect both of the substrate and the aroma upon the cells. Therefore, cells adsorption onto pieces of methyl polymethacrylate and of DupUM(®) was studied and further used in the biotransformation of castor oil into γ-decalactone. The highest aroma concentration was obtained with immobilized cells in DupUM(®), where reconsumption of the aroma by the cells was prevented, contrarily to what happens with free cells. This is a very promising result for γ-decalactone production, with potential to be used at an industrial level since the use of immobilized cells system will facilitate the conversion of a batch process into a continuous mode keeping high cell density and allowing easier recovery of metabolic products.

  2. Silica-Immobilized Enzyme Reactors

    DTIC Science & Technology

    2007-08-01

    relief from the symptoms of inflammation and pain Silica-IMERs 10 and is the mode of action of drugs such as aspirin and ibuprofen .[61] Serotonin...supports and using the enantiomeric selectivity of the enzyme to resolve racemic mixtures.[100] Immobilization onto supports with various pore sizes and...activity (~37%) and used as a packed- bed IMER to catalyze the racemic resolution of (S)-ketoprofen from its constituent enantiomers . The optically pure (S

  3. Immobilized Enzymes for Automated Analyses.

    DTIC Science & Technology

    1979-12-01

    by others. Reaction velocity was found to increase with temperature at a rate of about 5%/’C. Three distinct types of immobilization processes were...trifunctional silane ........... 10 2 Linearity of protein assay ............................. 14 3 Reaction rate for native and oxygenated enzyme solu...in a clinical chemistry analyzer enables catalysis of the analyzer reactions with retention of active enzyme by the system for subsequent reuse. When a

  4. Fast multipoint immobilized MOF bioreactor.

    PubMed

    Liu, Wan-Ling; Wu, Cheng-You; Chen, Chien-Yu; Singco, Brenda; Lin, Chia-Her; Huang, Hsi-Ya

    2014-07-14

    An enzyme-NBD@MOF bioreactor with exemplary proteolytic performance, even after successive reuse and storage, was produced through a novel, rapid and simple multipoint immobilization technique without chemical modification of the solid support. Enzyme loading and distribution could be directly monitored from the fluorescence emission of the bioreactor. The dye molecular dimension plays a role in its overall performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Light transfer in agar immobilized microalgae cell cultures

    NASA Astrophysics Data System (ADS)

    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.

  6. In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

    SciTech Connect

    Davis, Robert, J.

    2007-11-14

    Immobilized organometallic catalysts, in principle, can give high rates and selectivities like homogeneous catalysts with the ease of separation enjoyed by heterogeneous catalysts. However, the science of immobilized organometallics has not been developed because the field lies at the interface between the homogeneous and heterogeneous catalysis communities. By assembling an interdisciplinary research team that can probe all aspects of immobilized organometallic catalyst design, the entire reacting system can be considered, where the transition metal complex, the complex-support interface and the properties of the support can all be considered simultaneously from both experimental and theoretical points of view. Researchers at Georgia Tech and the University of Virginia are studying the fundamental principles that can be used to understand and design future classes of immobilized organometallic catalysts. In the framework of the overall collaborative project with Georgia Tech, our work focused on (a) the X-ray absorption spectroscopy of an immobilized Pd-SCS-O complex (b) the mode of metal leaching from supported Pd catalysts during Heck catalysis and (c) the mode of deactivation of Jacobsen’s Co-salen catalysts during the hydrolytic kinetic resolution of terminal epoxides. Catalysts containing supported Pd pincer complexes, functionalized supports containing mercapto and amine groups, and oligomeric Co-salen catalysts were synthesized at Georgia Tech and sent to the University of Virginia. Incorporation of Pd onto several different kinds of supports (silica, mercapto-functionalized silica, zeolite Y) was performed at the University of Virginia.

  7. Surplus plutonium immobilization feed materials requirements and blending strategy

    SciTech Connect

    Ebbinghaus, B.; Edmunds, T.; Gray, L.; Riley, D.; Rising, T.L.

    1998-02-13

    The Excess Fissile Materials Disposition Program`s Record of Decision (ROD) published in January 1997 by DOE/MD describes three potential pathways for the disposition of excess fissile materials: burning as MOX fuel rods, and two can-in-canister immobilization candidates: glass and ceramics. In addition, the ROD introduced processing schedules for MD disposition program. Prior to the ROD, the only acceptance specification that AMD had for incoming materials was DOE- STD-3013. However, STD-3013 is a specification aimed at maintaining safety for long term storage (approximately 100 years) and was never intended to act as an acceptance specification. An effort has begun to examine all of the technical issues associated with the processing and transfer of materials from EM to MD. Since that time, several related initiatives have begun to deal with the many issues, including the EM Material Stewardship program, the latest EM-66 sponsored trade studies, and a new storage standard. A draft of feed material requirements for the ceramic Immobilization Facility that will be used for the disposition of surplus plutonium has been developed for discussion. It established impurity limits for feed materials to the immobilization process, identifies impurities in feed materials that may have an adverse effect on the immobilization process, and indicates how these materials can be further processed and blended at the Immobilization Facility to ensure manufacture of an acceptable product.

  8. Immobilized Thylakoids in a Cross-Linked Albumin Matrix

    PubMed Central

    Thomasset, Brigitte; Thomasset, Thierry; Vejux, Alain; Jeanfils, Joseph; Barbotin, Jean-Noël; Thomas, Daniel

    1982-01-01

    Immobilization of lettuce (Lactuca sativa) thylakoids has been performed by using glutaraldehyde and bovine serum albumin. Confirming previous reports, a stabilization of the O2 evolution activity of the photosystem II (PSII) under storage and functional conditions has been observed. The present work is devoted to the role played by mono-and divalent cations, during the immobilization process itself, on the O2 production. Four types of measurements have been employed: kinetic measurements, low temperature (77 K) fluorescence emission, photoacoustic (PA) spectroscopy, and electron microscopy observations. We show that the effect of glutaraldehyde is complex because it acts as an inhibitor, a stabilizing agent, and a cross-linking reactive. In the present studies, the thylakoids are immobilized within a polymeric insoluble albumin matrix. The highest activity yield and the best storage conditions are obtained when 0.15 mm Na+ (or K+), 1 mm Mg2+, and 0.1 mm Mn2+ are present in the resuspending media before the immobilization. Due to modifications of the ionic content during such a process, structural differences are observed on the stacking degree of thylakoids. No modification of the fluorescence and PA spectra after the immobilization are found. Furthermore, a correlation between activities and spectral changes have been shown: when the activities increase, the F735 to F695 ratio increases and the PA676 to PA440 ratio decreases. Images Fig. 2 Fig. 5 PMID:16662563

  9. [Immobilization of heavy metal Pb2+ with geopolymer].

    PubMed

    Jin, Man-tong; Jin, Zan-fang; Huang, Cai-ju

    2011-05-01

    A series of geopolymers were synthesized by mixing metakaolinite, water glass, sodium hydroxide and water, and the lead ion solidification experiments were performed with the geopolymer. Then, the immobilization efficiency was characterized by monitoring the leaching concentration and compressive strength of solidified products. Additionally, the structure and properties of the solidified products were studied by X-ray diffraction (XRD), scan electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of immobilization efficiency, microstructure and mineral structure, the difference between geopolymer and cement on the performance of immobilizing heavy metals was discussed. The results of lead ion immobilization experiments showed that over 99.7% of heavy metal was captured by the geopolymer as the doping concentration of lead ion was less than 3%. Meanwhile, the compressive strength of the solidified product ranged from 40 MPa to 50 MPa. Furthermore, by using the same Pb2+ concentration, the geopolymer showed higher compressive strength and lower leaching concentration compared to the cement. Because lead ion participated in constitution of structure of geopolymer, or Pb2+ was adsorbed by the aluminium ions on the geopolymeric skeleton and held in geopolymer. However, cement mainly solidified lead ion by physical encapsulation and adsorption mechanism. Therefore, both from the compressive strength and leaching concentration and from the microstructure characterization as well as the mechanism of the geopolymerization reaction, the geopolymer has more advantages in immobilizing Pb2+ than the cement.

  10. Industrial applications of immobilized cells

    SciTech Connect

    Linko, P.; Linko, Y.Y.

    1984-01-01

    Although the application of the natural attraction of many microorganisms to surfaces has been applied in vinegar production since the early 1980s, and has long been utilized in waste water purification, the development of microbial cell immobilization techniques for special applications dates back only to the early 1960s. The immobilization may involve whole cells, cell fragments, or lysed cells. Whole cells may retain their metabolic activity with their complex multienzyme systems and cofactor regeneration mechanisms intact, or they may be killed in the process with only a few desired enzymes remaining active in the final biocatalyst. Cells may also be coimmobilized with an enzyme to carry out special reactions. Although relatively few industrial scale applications exist today, some are of very large scale. Current applications vary from relatively small scale steroid conversions to amino acid production and high fructose syrup manufacture. A vast number of potential applications are already known, and one of the most interesting applications may be in continuous fermentation such as ethanol production by immobilized living microorganisms. 373 references.

  11. Photo induced surface heparin immobilization.

    PubMed

    Nakayama, Y; Matsuda, T

    1993-01-01

    This paper describes a novel method providing durable layering of heparin immobilized hydrogels on fabricated devices. The preparation method is based on photochemistry of a dithiocarbamate group that is dissociated into a highly reactive radical pair upon ultraviolet (UV) irradiation. By taking advantage of characteristics of the photo generated radicals, hydrogel formation and its fixation onto a substrate surface were attained. The immobilization of heparin onto poly(ethylene terephtalate) was demonstrated. First, a mixed aqueous solution containing a photoreactive water soluble poly(N,N-dimethylacrylamide-covinylbenzyl N,N-diethyldithiocarbamate) and heparin was coated on the substrate. Subsequent UV irradiation resulted in the simultaneous formation of a heparin immobilized hydrogel and its chemical fixation onto the substrate. No delamination was found after vigorous washing with water. Significant inhibition of platelet adhesion and markedly prolonged blood coagulation times were observed, which are apparently derived from the surface hydrogel, and from released and chemically fixed surface heparin. Thus, it is expected that the photochemical method developed here provides potent antithrombogenicity to artificial organs.

  12. A facile and effective immobilization of glucose oxidase on tannic acid modified CoFe2O4 magnetic nanoparticles.

    PubMed

    Altun, Seher; Çakıroğlu, Bekir; Özacar, Münteha; Özacar, Mahmut

    2015-12-01

    This article presents a study of glucose oxidase (GOx) immobilization by employing tannic acid (TA) modified-CoFe2O4 (CFO) magnetic nanoparticles which demonstrates novel aspect for enzyme immobilization. By using the strong protein and tannic acid binding, GOx immobilization was carried out via physical adsorption in a simpler way compared with the other immobilization methods which require various chemicals and complicated procedures which is difficult, expensive, time-consuming, and destructive to the enzyme structure. CFO was synthesized by hydrothermal synthesis and modified with TA to immobilize GOx. The immobilized GOx demonstrated maximum catalytic activity at pH 6.5 and 45 °C. The samples were characterized by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, and fourier transform infrared spectroscopy (FTIR), all of which confirm the surface modification of CFO and GOx immobilization. Also, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were performed to demonstrate the surface morphology and chemical structure of samples. According to the Lineweaver-Burk plot, GOx possessed lower affinity to glucose after immobilization, and the Michelis-Menten constant (KM) of immobilized and free GOx were found to be 50.05 mM and 28.00 mM, respectively. The immobilized GOx showed excellent reusability, and even after 8 consecutive activity assay runs, the immobilized GOx maintained ca. 60% of its initial activity.

  13. Anticoagulation and antiplatelet effects of semax under conditions of acute and chronic immobilization stress.

    PubMed

    Grigorjeva, M E; Lyapina, L A

    2010-07-01

    The effects of semax on anticoagulant, fibrinolytic, and platelet components of the anticoagulation system were studied on albino rats under conditions of acute and chronic immobilization stress. Semax exhibited a protective antistress effect after repeated intranasal administration under conditions of hypercoagulation developing in response to immobilization stress of different degree. The effect manifested in stimulation of the anticoagulation system.

  14. Covalent immobilization of ascorbate oxidase onto polycarbonate strip for L-ascorbic acid detection.

    PubMed

    Kannoujia, Dileep Kumar; Kumar, Saroj; Nahar, Pradip

    2012-10-01

    Herein, a simple and rapid method is described for detection of L-ascorbic acid by ascorbate oxidase immobilized onto polycarbonate strip pre-activated by 1-fluoro-2-nitro-4-azidobenzene in photochemical reaction. Covalent attachment of ascorbate oxidase was confirmed by XPS studies. The immobilized-ascorbate oxidase shows higher pH, thermal and storage stability in comparison to free enzyme.

  15. Changes in physical examination caused by use of spinal immobilization.

    PubMed

    March, Juan A; Ausband, Stephen C; Brown, Lawrence H

    2002-01-01

    The standard of care for patients following blunt trauma includes midline palpation of vertebrae to rule out fractures. Previous studies have demonstrated that spinal immobilization does cause discomfort. To determine whether spinal immobilization causes changes in physical exam findings over time. This was a single-blinded, prospective study at a tertiary care university teaching hospital. Twenty healthy volunteers without previous back pain or injuries, 13 male and seven female, were fully immobilized for one hour, with a cervical collar and strapped to a long wooden backboard. Midline palpation of vertebrae to illicit pain was performed at 10-minute intervals. In addition, the participants were asked to rate neck and back pain on a scale from 1 to 10 (1 for no pain, and 10 for unbearable pain), to see whether subjective pain from immobilization correlated with tenderness to palpation. Three patients had point tenderness of cervical vertebrae within 40 minutes. Five patients developed point tenderness of vertebrae by 60 minutes. Eighteen of 20 participants complained of increasing discomfort over time. The median initial pain scale was 1 (range 1-1), in contrast to 4 (range 1-9) at 60 minutes, p < 0.05. This study shows that over time, standard immobilization causes a false-positive exam for midline vertebral tenderness. In order to reduce this high false-positive rate for midline vertebral tenderness, the authors recommend that, initially on arrival to the emergency department, immediate evaluation occur of all immobilized patients. Furthermore, backboards should be modified to reduce patient discomfort to prevent the iatrogenically induced midline vertebral tenderness, thereby reducing subsequent false-positive examinations.

  16. Immobilized enzymes in blood plasma exchangers via radiation grafting

    NASA Astrophysics Data System (ADS)

    Gombotz, Wayne; Hoffman, Allan; Schmer, Gottfried; Uenoyama, Satoshi

    The enzyme asparaginase was immobilized onto a porous hollow polypropylene (PP) fiber blood plasma exchange device for the treatment of acute lymphocytic leukemia. The devices were first radiation grafted with polymethacrylic acid (poly(MAAc)). This introduces carboxyl groups onto the surface of the fibers. Several variables were studied in the grafting reaction including the effects of solvent type and monomer concentration. The carboxyl groups were activated with N-hydroxy succinimide (NHS) using carbodiimide chemistry. Asparaginase was then covalently immobilized on the activated surfaces. Quantitative relationships were found relating the percent graft to the amount of immobilized enzyme which was active. The enzyme reactor was tested both in vitro and in vivo using a sheep as an animal model.

  17. Purification, immobilization, and characterization of nattokinase on PHB nanoparticles.

    PubMed

    Deepak, Venkataraman; Pandian, Suresh babu Ram Kumar; Kalishwaralal, Kalimuthu; Gurunathan, Sangiliyandi

    2009-12-01

    In this study, nattokinase was purified from Bacillus subtilis using ion exchange chromatography and immobilized upon polyhydroxybutyrate (PHB) nanoparticles. A novel strain isolated from industrial dairy waste was found to synthesize polyhydroxyalkanoates (PHA) and the strain was identified as Brevibacterium casei SRKP2. PHA granules were extracted from 48 h culture and the FT-IR analysis characterized them as PHB, a natural biopolymer from B. casei. Nanoprecipitation by solvent displacement technique was used to synthesize PHB nanoparticles. PHB nanoparticles were characterized using transmission electron microscopy and particle size ranged from 100-125 nm. Immobilization of nattokinase upon PHB nanoparticles resulted in a 20% increase in the enzyme activity. Immobilization also contributed to the enhanced stability of the enzyme. Moreover, the activity was completely retained on storage at 4 degrees C for 25 days. The method has proven to be highly simple and can be implemented to other enzymes also.

  18. Immobilization of photosynthetic reaction centers on metal surfaces

    SciTech Connect

    Cotton, T.M.; Chumanov, G.; Gual, D.

    1993-12-31

    Membrane-bound proteins are ideal candidates for immobilization on surfaces because of their distinct hydrophobic and hydrophilic regions. Their interaction with a particular surface should depend upon its hydrophilicity. Variation of the surface properties is expected to result in changes in the orientation of an absorbed protein. In this study, two methods for immobilization of reaction centers from Rhodobacter sphaeroids on metal surfaces have been compared, including self-assembly or spontaneous adsorption and Langmuir-Blodgett transfer of monolayers from an air/water interface. The effect of the immobilization procedure on the structure of the protein complex has been determined from photochemical activity and optical measurements. The experimental variables which are critical for maintaining the structure and function of the protein in the adsorbed state will be discussed.

  19. Lipase-immobilized biocatalytic membranes for biodiesel production.

    PubMed

    Kuo, Chia-Hung; Peng, Li-Ting; Kan, Shu-Chen; Liu, Yung-Chuan; Shieh, Chwen-Jen

    2013-10-01

    Microbial lipase from Candida rugosa (Amano AY-30) has good transesterification activity and can be used for biodiesel production. In this study, polyvinylidene fluoride (PVDF) membrane was grafted with 1,4-diaminobutane and activated by glutaraldehyde for C. rugosa lipase immobilization. After immobilization, the biocatalytic membrane was used for producing biodiesel from soybean oil and methanol via transesterification. Response Surface Methodology (RSM) in combination with a 5-level-5-factor central composite rotatable design (CCRD) was employed to evaluate the effects of reaction time, reaction temperature, enzyme amount, substrate molar ratio and water content on the yield of soybean oil methyl ester. By ridge max analysis, the predicted and experimental yields under the optimum synthesis conditions were 97% and 95%, respectively. The lipase-immobilized PVDF membrane showed good reuse ability for biodiesel production, enabling operation for at least 165 h during five reuses of the batch, without significant loss of activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Characterization of phase evolution during lead immobilization by synthetic hydroxyapatite

    SciTech Connect

    Mavropoulos, Elena; Rocha, Nilce C.C.; Soares, Gloria A. . E-mail: Gloria@ufrj.br

    2004-09-15

    Immobilization of toxic metals by calcium phosphates is a promising technology for treating contaminated soil, water and wastes. A detailed study on the mechanisms of lead immobilization by hydroxyapatite has been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). For this, synthetic hydroxyapatite powder were submitted to a sorption process through exposure to an aqueous solution containing 917 mg L{sup -1} of lead for times that varied from 3 min to 54 h. The results obtained reinforce the hypothesis that hydroxypyromorphite formation is the end of a kinetic process in which the hydroxyapatite crystals are continuously dissolved and recrystallized in order to form more stable structures with higher lead content. Consequently, the use of calcium phosphates to immobilize lead ions seems to be technically viable.

  1. Immobilization of silver nanoparticles on silica microspheres

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Kai; Chen, Chia-Yin; Han, Jin-Lin; Chen, Chii-Chang; Jiang, Meng-Dan; Hsu, Jen-Sung; Chan, Chia-Hua; Hsieh, Kuo-Huang

    2010-01-01

    The silver nanoparticles (Ag NPs) have been immobilized onto silica microspheres through the adsorption and subsequent reduction of Ag+ ions on the surfaces of the silica microspheres. The neat silica microspheres that acted as the core materials were prepared through sol-gel processing; their surfaces were then functionalized using 3-mercaptopropyltrimethoxysilane (MPTMS). The major aims of this study were to immobilize differently sized Ag particles onto the silica microspheres and to understand the mechanism of formation of the Ag nano-coatings through the self-assembly/adsorption behavior of Ag NPs/Ag+ ions on the silica spheres. The obtained Ag NP/silica microsphere conglomerates were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). Their electromagnetic wave shielding effectiveness were also tested and studied. The average particle size of the obtained Ag NPs on the silica microsphere was found that could be controllable (from 2.9 to 51.5 nm) by adjusting the ratio of MPTMS/TEOS and the amount of AgNO3.

  2. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres.

    PubMed

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A; El-Toni, Ahmed M; Almaary, Khalid S; El-Tayeb, Mohamed A; Elbadawi, Yahya B; Antranikian, Garabed

    2016-01-29

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS-NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V(max), k(cat) and k(cat)/K(m), than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media.

  3. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres

    PubMed Central

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A.; El-Toni, Ahmed M.; Almaary, Khalid S.; El-Tayeb, Mohamed A.; Elbadawi, Yahya B.; Antranikian, Garabed

    2016-01-01

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS–NH2 nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher Vmax, kcat and kcat/Km, than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media. PMID:26840303

  4. Immobilization of Penaeus merguiensis alkaline phosphatase on gold nanorods for heavy metal detection.

    PubMed

    Homaei, Ahmad

    2017-02-01

    Biotechnology of enzyme has gained popularity due to the growing need for novel environmental technologies and the development of innovative mass-production. The work describes the original application of biosensors based on Penaeus merguiensis alkaline phosphatase (PM ALP) immobilized on gold nanorods (GNRs) to heavy metal determination. Penaeus merguiensis alkaline phosphatase (PM ALP) was immobilized on gold nanorods (GNRs) by ionic exchange and hydrophobic interactions. The optimum pH and temperature for maximum enzyme activity for the immobilized PM ALP are identified to be 11.0 and 60°C, respectively, for the hydrolysis of para-Nitrophenylphosphate (p-NPP). The kinetic studies confirm the Michaelis-Menten behavior and suggests overall slightly decrease in the performance of the immobilized enzyme with reference to the free enzyme. Km and Vmax values were 0.32µm and 54µm. min(-1) for free and 0.39µm and 48µmmin(-1) for immobilized enzymes, respectively. Similarly, the thermal stability, storage stability and stability at extreme pH of the enzyme is found to increase after the immobilization. The inhibitory effect heavy metal ions was studied on free and immobilized PM ALP. The bi-enzymatic biosensor were tested to study the influence of heavy metal ions and pesticides on the corresponding enzyme. The obtained high stability and lower decrease in catalytic efficiency suggested the great potential and feasibility of immobilized PM ALP nanobiocatalyst in efficient and apply the biosensor in total toxic metal content determination.

  5. Utilization of immobilized urease for waste water treatment

    NASA Technical Reports Server (NTRS)

    Husted, R. R.

    1974-01-01

    The feasibility of using immobilized urease for urea removal from waste water for space system applications is considered, specifically the elimination of the urea toxicity problem in a 30-day Orbiting Frog Otolith (OFO) flight experiment. Because urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, control of their concentrations within nontoxic limits was also determined. The results of this study led to the use of free urease in lieu of the immobilized urease for controlling urea concentrations. An ion exchange resin was used which reduced the NH3 level by 94% while reducing the sodium ion concentration only 10%.

  6. Analysis of alternatives for immobilized low activity waste disposal

    SciTech Connect

    Burbank, D.A.

    1997-10-28

    This report presents a study of alternative disposal system architectures and implementation strategies to provide onsite near-surface disposal capacity to receive the immobilized low-activity waste produced by the private vendors. The analysis shows that a flexible unit strategy that provides a suite of design solutions tailored to the characteristics of the immobilized low-activity waste will provide a disposal system that best meets the program goals of reducing the environmental, health, and safety impacts; meeting the schedule milestones; and minimizing the life-cycle cost of the program.

  7. Drop drying on surfaces determines chemical reactivity - the specific case of immobilization of oligonucleotides on microarrays

    PubMed Central

    2013-01-01

    Background Drop drying is a key factor in a wide range of technical applications, including spotted microarrays. The applied nL liquid volume provides specific reaction conditions for the immobilization of probe molecules to a chemically modified surface. Results We investigated the influence of nL and μL liquid drop volumes on the process of probe immobilization and compare the results obtained to the situation in liquid solution. In our data, we observe a strong relationship between drop drying effects on immobilization and surface chemistry. In this work, we present results on the immobilization of dye labeled 20mer oligonucleotides with and without an activating 5′-aminoheptyl linker onto a 2D epoxysilane and a 3D NHS activated hydrogel surface. Conclusions Our experiments identified two basic processes determining immobilization. First, the rate of drop drying that depends on the drop volume and the ambient relative humidity. Oligonucleotides in a dried spot react unspecifically with the surface and long reaction times are needed. 3D hydrogel surfaces allow for immobilization in a liquid environment under diffusive conditions. Here, oligonucleotide immobilization is much faster and a specific reaction with the reactive linker group is observed. Second, the effect of increasing probe concentration as a result of drop drying. On a 3D hydrogel, the increasing concentration of probe molecules in nL spotting volumes accelerates immobilization dramatically. In case of μL volumes, immobilization depends on whether the drop is allowed to dry completely. At non-drying conditions, very limited immobilization is observed due to the low oligonucleotide concentration used in microarray spotting solutions. The results of our study provide a general guideline for microarray assay development. They allow for the initial definition and further optimization of reaction conditions for the immobilization of oligonucleotides and other probe molecule classes to different

  8. Alginate immobilized enrichment culture for atrazine degradation in soil and water system.

    PubMed

    Kumar, Anup; Nain, Lata; Singh, Neera

    2017-04-03

    An atrazine degrading enrichment culture, a consortium of bacteria of genus Bacillus along with Pseudomonas and Burkholderia, was immobilized in sodium alginate and was used to study atrazine degradation in mineral salts medium (MSM), soil and wastewater effluent. Sodium alginate immobilized consortium, when stored at room temperature (24 ± 5°C), was effective in degrading atrazine in MSM up to 90 days of storage. The survival of bacteria in alginate beads, based on colony formation unit (CFU) counts, suggested survival up to 90 days and population counts decreased to 1/5(th) on 120 days. Comparison of atrazine degrading ability of the freely suspended enrichment culture and immobilized culture suggested that the immobilized culture took longer time for complete degradation of atrazine as a lag phase of 2 days was observed in the MSM inoculated with alginate immobilized culture. The free cells resulted in complete degradation of atrazine within 6 days, while immobilized cells took 10 days for 100% atrazine degradation. Further, immobilized cultures were able to degrade atrazine in soil and wastewater effluent. Alginate beads were stable and effective in degrading atrazine till 3rd transfer and disintegrated thereafter. The study suggested that immobilized enrichment culture, due to its better storage and application, can be used to degrade atrazine in soil water system.

  9. Immobilization of α-amylase onto a calix[4]arene derivative: Evaluation of its enzymatic activity.

    PubMed

    Veesar, Irshad Ali; Solangi, Imam Bakhsh; Memon, Shahabuddin

    2015-06-01

    In order to enhance the cost-effectiveness practicability of enzymes in many industries such as pharmaceutical, food, medical and some other technological processes, there is great need to immobilize them onto a solid supports. In this study, a new and efficient immobilization of α-amylase from Saccharomyces cerevisiae has been developed by using the surface functionalization of calix[4]arene as support. A glutaraldehyde-containing amino group functionalized calix[4]arene was used to immobilize α-amylase covalently. In this procedure, imide bonds are formed between amino groups on the protein and aldehyde groups on the calix[4]arene surface. The surface modified support was characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM). The effect of various preparation conditions on the immobilized α-amylase process such as immobilization time, enzyme concentration, temperature and pH were investigated. The influence of pH and temperature on the activity of free and immobilized α-amylase was also studied using starch as substrate. The optimum reaction temperature and pH value for the enzymatic conversion catalyzed by the immobilized α-amylase were 25°C and 7, respectively. Compared to the free enzyme, the immobilized α-amylase retained 85% of its original activity and exhibited significant thermal stability than the free one and excellent durability. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. pH-dependent immobilization of urease on glutathione-capped gold nanoparticles.

    PubMed

    Garg, Seema; De, Arnab; Mozumdar, Subho

    2015-05-01

    Urease is a nickel-dependent metalloenzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability, and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple, and reliable immobilization strategy for the enzyme. In this study, the carboxyl terminated surface of glutathione-capped gold nanoparticles have been utilized as a solid support for the covalent attachment of urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bioactivity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like ultraviolet-visible spectroscopy, intrinsic steady state fluorescence, and circular dichorism. The bioactivity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nanoconjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future.

  11. Effects of fasting and immobilization stresses on the phagocytic capacity of rat polymorphonuclear phagocyte monolayers.

    PubMed

    Quindos, G; Ruiz de Gordoa, J C; Burgos, A; Ponton, J; Cisterna, R

    1986-01-01

    The effect of two different types of acute stress (immobilization and fasting) on the polymorphonuclear leukocyte phagocytic function has been studied in male and female rats. With this aim, a subgroup of rats was under immobilization and fasting, another under complete energy deprivation and a third one (controls), exposed to the normal activity of the animal room, for 15 hours. The stress induction was assessed by controlling weight variations and gastric ulcers generation. Both stressors induced weight loss but only immobilization resulted in the development of gastric ulcer in all the animals studied. Phagocytosis was increased in male rats stressed by fasting and in immobilized female rats. In the remaining subgroups polymorphonuclear leukocyte cells showed a phagocytic capacity within the range of control values. Only comparison of the males group stressed by fasting with the male group stressed by fasting and immobilization showed a significant depression in phagocytosis.

  12. Immobilization of alliinase on porous aluminum oxide.

    PubMed

    Milka, P; Krest, I; Keusgen, M

    2000-08-05

    Membrane filters prepared from porous aluminum oxide (Anopore) were investigated for their potential use as a durable support for enzymes. Alliinase (EC 4.4.1.4) was chosen as a model enzyme for immobilization experiments. To allow for smooth fixation, the enzyme was immobilized indirectly by sugar-lectin binding. Monomolecular layers of the lectin concanavalin A and alliinase were applied by self-assembling processes. As an anchor for these layers, the sugar, mannan, was covalently coupled to the membrane surface. This procedure exhibits several advantages: (i) enzyme immobilization can be carried out under smooth conditions; (ii) immobilization needs little time; and (iii) protein layers may be renewed.

  13. Synthesis and heavy metal immobilization behaviors of slag based geopolymer.

    PubMed

    Yunsheng, Zhang; Wei, Sun; Qianli, Chen; Lin, Chen

    2007-05-08

    In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavy metals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reach 98.5% greater when heavy metals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavy metals.

  14. Venous Thrombosis Risk after Cast Immobilization of the Lower Extremity: Derivation and Validation of a Clinical Prediction Score, L-TRiP(cast), in Three Population-Based Case-Control Studies.

    PubMed

    Nemeth, Banne; van Adrichem, Raymond A; van Hylckama Vlieg, Astrid; Bucciarelli, Paolo; Martinelli, Ida; Baglin, Trevor; Rosendaal, Frits R; le Cessie, Saskia; Cannegieter, Suzanne C

    2015-11-01

    Guidelines and clinical practice vary considerably with respect to thrombosis prophylaxis during plaster cast immobilization of the lower extremity. Identifying patients at high risk for the development of venous thromboembolism (VTE) would provide a basis for considering individual thromboprophylaxis use and planning treatment studies. The aims of this study were (1) to investigate the predictive value of genetic and environmental risk factors, levels of coagulation factors, and other biomarkers for the occurrence of VTE after cast immobilization of the lower extremity and (2) to develop a clinical prediction tool for the prediction of VTE in plaster cast patients. We used data from a large population-based case-control study (MEGA study, 4,446 cases with VTE, 6,118 controls without) designed to identify risk factors for a first VTE. Cases were recruited from six anticoagulation clinics in the Netherlands between 1999 and 2004; controls were their partners or individuals identified via random digit dialing. Identification of predictor variables to be included in the model was based on reported associations in the literature or on a relative risk (odds ratio) > 1.2 and p ≤ 0.25 in the univariate analysis of all participants. Using multivariate logistic regression, a full prediction model was created. In addition to the full model (all variables), a restricted model (minimum number of predictors with a maximum predictive value) and a clinical model (environmental risk factors only, no blood draw or assays required) were created. To determine the discriminatory power in patients with cast immobilization (n = 230), the area under the curve (AUC) was calculated by means of a receiver operating characteristic. Validation was performed in two other case-control studies of the etiology of VTE: (1) the THE-VTE study, a two-center, population-based case-control study (conducted in Leiden, the Netherlands, and Cambridge, United Kingdom) with 784 cases and 523 controls

  15. Venous Thrombosis Risk after Cast Immobilization of the Lower Extremity: Derivation and Validation of a Clinical Prediction Score, L-TRiP(cast), in Three Population-Based Case–Control Studies

    PubMed Central

    Nemeth, Banne; van Adrichem, Raymond A.; van Hylckama Vlieg, Astrid; Bucciarelli, Paolo; Martinelli, Ida; Baglin, Trevor; Rosendaal, Frits R.; le Cessie, Saskia; Cannegieter, Suzanne C.

    2015-01-01

    Background Guidelines and clinical practice vary considerably with respect to thrombosis prophylaxis during plaster cast immobilization of the lower extremity. Identifying patients at high risk for the development of venous thromboembolism (VTE) would provide a basis for considering individual thromboprophylaxis use and planning treatment studies. The aims of this study were (1) to investigate the predictive value of genetic and environmental risk factors, levels of coagulation factors, and other biomarkers for the occurrence of VTE after cast immobilization of the lower extremity and (2) to develop a clinical prediction tool for the prediction of VTE in plaster cast patients. Methods and Findings We used data from a large population-based case–control study (MEGA study, 4,446 cases with VTE, 6,118 controls without) designed to identify risk factors for a first VTE. Cases were recruited from six anticoagulation clinics in the Netherlands between 1999 and 2004; controls were their partners or individuals identified via random digit dialing. Identification of predictor variables to be included in the model was based on reported associations in the literature or on a relative risk (odds ratio) > 1.2 and p ≤ 0.25 in the univariate analysis of all participants. Using multivariate logistic regression, a full prediction model was created. In addition to the full model (all variables), a restricted model (minimum number of predictors with a maximum predictive value) and a clinical model (environmental risk factors only, no blood draw or assays required) were created. To determine the discriminatory power in patients with cast immobilization (n = 230), the area under the curve (AUC) was calculated by means of a receiver operating characteristic. Validation was performed in two other case–control studies of the etiology of VTE: (1) the THE-VTE study, a two-center, population-based case–control study (conducted in Leiden, the Netherlands, and Cambridge, United Kingdom

  16. Immobilized lipid-bilayer materials

    DOEpatents

    Sasaki, Darryl Y.; Loy, Douglas A.; Yamanaka, Stacey A.

    2000-01-01

    A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

  17. Elucidation of the effect of aptamer immobilization strategies on the interaction between cell and its aptamer using atomic force spectroscopy.

    PubMed

    Wang, Qing; Luo, Bianxia; Yang, Xiaohai; Wang, Kemin; Liu, Lin; Du, Shasha; Li, Zhiping

    2016-04-01

    The immobilization strategy of cell-specific aptamers is of great importance for studying the interaction between a cell and its aptamer. However, because of the difficulty of studying living cell, there have not been any systematic reports about the effect of immobilization strategies on the binding ability of an immobilized aptamer to its target cell. Because atomic force spectroscopy (AFM) could not only be suitable for the investigation of living cell under physiological conditions but also obtains information reflecting the intrinsic properties of individuals, the effect of immobilization strategies on the interaction of aptamer/human hepatocarcinoma cell Bel-7404 was successively evaluated using AFM here. Two different immobilization methods, including polyethylene glycol immobilization method and glutaraldehyde immobilization method were used, and the factors, such as aptamer orientation, oligodeoxythymidine spacers and dodecyl spacers, were investigated. Binding events measured by AFM showed that a similar unbinding force was obtained regardless of the change of the aptamer orientation, the immobilization method, and spacers, implying that the biophysical characteristics of the aptamer at the molecular level remain undisturbed. However, it showed that the immobilization orientation, immobilization method, and spacers could alter the binding probability of aptamer/Bel-7404 cell. Presumably, these factors may affect the accessibility of the aptamer toward its target cell. These results may provide valuable information for aptamer sensor platforms including ultrasensitive biosensor design. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Improved performance of α-amylase immobilized on poly(glycidyl methacrylate-co-ethylenedimethacrylate) beads.

    PubMed

    He, Tian; Tian, Yong-Le; Qi, Liang; Zhang, Jing; Zhang, Zhi-Qi

    2014-04-01

    α-Amylase was successfully immobilized onto poly(glycidyl methacrylate-co-ethylenedimethacrylate) (PGMA/EDMA) beads with high immobilization efficiency of 87.8%. PGMA/EDMA beads with a relatively uniform diameter of 2-3 μm were prepared by single-step swelling polymerization. After amination with ethanediamine and activation with glutaraldehyde, PGMA/EDMA beads showed commendable α-amylase immobilization capacity of 35.1 mg g(-1) carrier. Compared with free form, immobilized α-amylase had increasement of 12.94 mg mL(-1) for Km and 0.124 mmol mL(-1) min(-1) for Vmax, improved acid resistance (the optimal pH from 7 to 5), presented better thermal stability by retaining 61% activity than 40% at 90 °C, and displayed high operational reusability by retaining 58% of its initial activity after nine uses. Moreover, less than 10% of the free enzyme and more than 80% of the immobilized enzyme retained activity after 180 min pre-incubation at 50 °C. The easy modification, high immobilization efficiency and good properties of immobilized α-amylase in the present study indicate that PGMA/EDMA beads are suitable for α-amylase immobilization. The enhancement of acid resistance and thermo stability is doubtless of benefit for the industrial use of α-amylase.

  19. Cagelike mesoporous silica encapsulated with microcapsules for immobilized laccase and 2, 4-DCP degradation.

    PubMed

    Yang, Junya; Huang, Yan; Yang, Yuxiang; Yuan, Hongming; Liu, Xiangnong

    2015-12-01

    In this study, cage-like mesoporous silica was used as the carrier to immobilize laccase by a physical approach, followed by encapsulating with chitosan/alginate microcapsule membranes to form microcapsules of immobilized laccase based on layer-by-layer technology. The relationship between laccase activity recovery/leakage rate and the coating thickness was simultaneously investigated. Because the microcapsule layers have a substantial network of pores, they act as semipermeable membranes, while the laccase immobilized inside the microcapsules acts as a processing plant for degradation of 2,4-dichlorophenol. The microcapsules of immobilized laccase were able to degrade 2,4-dichlorophenol within a wide range of 2,4-dichlorophenol concentration, temperature and pH, with mean degradation rate around 62%. Under the optimal conditions, the thermal stability and reusability of immobilized laccase were shown to be improved significantly, as the removal rate and degradation rate remained over 40.2% and 33.8% respectively after 6cycles of operation. Using mass spectrometry (MS) and nuclear magnetic resonance (NMR), diisobutyl phthalate and dibutyl phthalate were identified as the products of 2,4-dichlorophenol degradation by the microcapsules of immobilized laccase and laccase immobilized by a physical approach, respectively, further demonstrating the degradation mechanism of 2,4-dichlorophenol by microcapsule-immobilized laccase. Copyright © 2015. Published by Elsevier B.V.

  20. Plasma lactate concentrations in free-ranging moose (Alces alces) immobilized with etorphine.

    PubMed

    Haga, Henning A; Wenger, Sandra; Hvarnes, Silje; Os, Oystein; Rolandsen, Christer M; Solberg, Erling J

    2009-11-01

    To investigate plasma lactate concentrations of etorphine-immobilized moose in relation to environmental, temporal and physiological parameters. Prospective clinical study. Fourteen female and five male moose (Alces alces), estimated age range 1-7 years. The moose were darted from a helicopter with 7.5 mg etorphine per animal using projectile syringes and a dart gun. Once immobilized, the moose were approached, a venous blood sample was obtained and vital signs including pulse oximetry were recorded. Diprenorphine was administered to reverse the effects of etorphine. Timing of events, ambient temperature and snow depth were recorded. Blood samples were cooled and centrifuged before plasma was harvested and frozen. The plasma was thawed later and lactate analysed. Data were analysed using descriptive statistics and regression analysis. All animals recovered uneventfully and were alive 12 weeks after immobilization. Mean +/- SD plasma lactate was found to be 9.2 +/- 2.1 mmol L(-1). Plasma lactate concentrations were related positively to snow depth and negatively to time from induction of immobilization to blood sampling. The model that best described the variability in plasma lactate concentrations used induction time (time from firing the dart to the moose being immobilized). The second best model included induction time and snow depth. Plasma lactate concentrations in these etorphine-immobilized moose were in the range reported for other immobilized wild ruminants. Decreasing induction time, which may be related to a more profound etorphine effect, and increasing snow depth possibly may increase plasma lactate concentrations in etorphine-immobilized moose.

  1. Aerobic degradation of nitrobenzene by immobilization of Rhodotorula mucilaginosa in polyurethane foam.

    PubMed

    Zheng, Chunli; Zhou, Jiti; Wang, Jing; Qu, Baocheng; Wang, Jing; Lu, Hong; Zhao, Hongxia

    2009-08-30

    Rhodotorula mucilaginosa Z1 capable of degrading nitrobenzene was immobilized in polyurethane foam. The nitrobenzene-degrading capacity of immobilized cells was compared to free cells in batches in shaken culture. Effects of pH and temperature on the nitrobenzene degradation showed that polyurethane-immobilized Z1 had higher tolerances toward acid, alkali, and heat than those of free cells. Kinetic studies revealed that higher concentrations of nitrobenzene were better tolerated and more quickly degraded by polyurethane-immobilized Z1 than by free cells. Moreover, the ability of polyurethane-immobilized Z1 to resist nitrobenzene shock load was enhanced. Experiments on the nitrobenzene degradation in different concentrations of NaCl and in the presence of phenol or aniline demonstrated that polyurethane-immobilized Z1 exhibited higher tolerance toward salinity and toxic chemicals than those of free cells. Immobilization therefore could be a promising method for treating nitrobenzene industrial wastewater. This is the first report on the degradation of nitrobenzene by a polyurethane-immobilized yeast strain.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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. Ethanol production from concentrated food waste hydrolysates with yeast cells immobilized on corn stalk.

    PubMed

    Yan, Shoubao; Chen, Xiangsong; Wu, Jingyong; Wang, Pingchao

    2012-05-01

    The aim of the present study was to examine ethanol production from concentrated food waste hydrolysates using whole cells of S. cerevisiae immobilized on corn stalks. In order to improve cell immobilization efficiency, biological modification of the carrier was carried out by cellulase hydrolysis. The results show that proper modification of the carrier with cellulase hydrolysis was suitable for cell immobilization. The mechanism proposed, cellulase hydrolysis, not only increased the immobilized cell concentration, but also disrupted the sleek surface to become rough and porous, which enhanced ethanol production. In batch fermentation with an initial reducing sugar concentration of 202.64 ± 1.86 g/l, an optimal ethanol concentration of 87.91 ± 1.98 g/l was obtained using a modified corn stalk-immobilized cell system. The ethanol concentration produced by the immobilized cells was 6.9% higher than that produced by the free cells. Ethanol production in the 14th cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in an immobilized cell reactor, the maximum ethanol concentration of 84.85 g/l, and the highest ethanol yield of 0.43 g/g (of reducing sugar) were achieved at hydraulic retention time (HRT) of 3.10 h, whereas the maximum volumetric ethanol productivity of 43.54 g/l/h was observed at a HRT of 1.55 h.

  4. Immobilization of pigeonpea (Cajanus cajan) urease on DEAE-cellulose paper strips for urea estimation.

    PubMed

    Reddy K, Ravi Charan; Srivastava, Punit K; Dey, Prakash M; Kayastha, Arvind M

    2004-06-01

    Pigeonpea ( Cajanus cajan ) urease was immobilized on 1 cmx1 cm DEAE-cellulose paper strips. The optimum immobilization (51% activity) was observed at 4 degrees C, with a protein concentration of 1.0 mg/strip. The apparent optimum pH shifted from 7.3 to 6.8. Immobilized urease showed an optimal stability temperature of 67 degrees C, compared with 47 degrees C for the soluble urease. Time-dependent kinetics of the thermal inactivation of the immobilized urease were examined and found to be monophasic as compared with the soluble enzyme, which was biphasic. The Michaelis constant ( K (m)) for the DEAE-cellulose-immobilized urease was found to be 4.75 mM, 1.5 times higher than the soluble enzyme. Immobilized strips stored at 4 degrees C showed an increased half-life ( t (1/2)=150 days). There was practically no leaching of the enzyme from the immobilized strips over a period of 2 weeks. These strips were used for estimating the urea content of blood samples; the results obtained matched well with those obtained in a clinical laboratory through an Autoanalyzer(R) (Zydus Co., Rome, Italy). The easy availability of pigeonpea urease, the ease of its immobilization on DEAE-cellulose strips and the significantly lower cost of urease described in the present study makes it a suitable product for future applications in diagnostics.

  5. Influence of acetylcholinesterase immobilization on the photoluminescence properties of mesoporous silicon surface

    NASA Astrophysics Data System (ADS)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2014-07-01

    Acetylcholinesterase immobilized p-type porous silicon surface was prepared by covalent attachment. The immobilization procedure was based on support surface chemical oxidation, silanization, surface activation with cyanuric chloride and finally covalent attachment of free enzyme on the cyanuric chloride activated porous silicon surface. Different pore diameter of porous silicon samples were prepared by electrochemical etching in HF based electrolyte solution and appropriate sample was selected suitable for enzyme immobilization with maximum trapping ability. The surface modification was studied through field emission scanning electron microscope, EDS, FT-IR analysis, and photoluminescence measurement by utilizing the fluctuation in the photoluminescence of virgin and enzyme immobilized porous silicon surface. Porous silicon showed strong photoluminescence with maximum emission at 643 nm and immobilization of acetylcholinesterase on porous silicon surface cause considerable increment on the photoluminescence of porous silicon material while acetylcholinesterase free counterpart did not exhibit any fluorescence in the range of 635-670 nm. The activities of the free and immobilized enzymes were evaluated by spectrophotometric method by using neostigmine methylsulfate as standard enzyme inhibitor. The immobilized enzyme exhibited considerable response toward neostigmine methylsulfate in a dose dependent manner comparable with that of its free counterpart alongside enhanced stability, easy separation from the reaction media and significant saving of enzyme. It was believed that immobilized enzyme can be exploited in organic and biomolecule synthesis possessing technical and economical prestige over free enzyme and prominence of easy separation from the reaction mixture.

  6. Polydopamine-mediated immobilization of multiple bioactive molecules for the development of functional vascular graft materials.

    PubMed

    Lee, Yu Bin; Shin, Young Min; Lee, Ji-Hye; Jun, Indong; Kang, Jae Kyeong; Park, Jong-Chul; Shin, Heungsoo

    2012-11-01

    In this study, we introduced a simple method for polydopamine-mediated immobilization of dual bioactive factors for the preparation of functionalized vascular graft materials. Polydopamine was deposited on elastic and biodegradable poly(lactic acid-co-ɛ-caprolactone) (PLCL) films, and a cell adhesive RGD-containing peptide and basic fibroblast growth factor were subsequently immobilized by simple dipping. We used an enzyme-linked immunosorbent assay and fluorescamine assay to confirm that we had stably immobilized bioactive molecules on the polydopamine-coated PLCL film in a reaction time-dependent manner. When human umbilical vein endothelial cells (HUVEC) were cultured on the prepared substrates, the number of adherent cells and proliferation of HUVEC for up to 14 days were greatest on the film immobilized with dual factors. On the other hand, the film immobilized with RGD peptide exhibited the highest migration speed compared to the other groups. The expression of cluster of differentiation 31 and von Willebrand factor, which indicates maturation of endothelial cells, was highly stimulated in the dual factor-immobilized group, and passively adsorbed factors showed a negligible effect. The immobilization of bioactive molecules inspired by polydopamine was successful, and adhesion, migration, proliferation and differentiation of HUVEC were synergistically accelerated by the presence of multiple signaling factors. Collectively, our results have demonstrated that a simple coating with polydopamine enables the immobilization of multiple bioactive molecules for preparation of polymeric functionalized vascular graft materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

    PubMed Central

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  8. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    PubMed

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-02-02

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. © 2016 Authors.

  9. Tunable control of antibody immobilization using electric field.

    PubMed

    Emaminejad, Sam; Javanmard, Mehdi; Gupta, Chaitanya; Chang, Shuai; Davis, Ronald W; Howe, Roger T

    2015-02-17

    The controlled immobilization of proteins on solid-state surfaces can play an important role in enhancing the sensitivity of both affinity-based biosensors and probe-free sensing platforms. Typical methods of controlling the orientation of probe proteins on a sensor surface involve surface chemistry-based techniques. Here, we present a method of tunably controlling the immobilization of proteins on a solid-state surface using electric field. We study the ability to orient molecules by immobilizing IgG molecules in microchannels while applying lateral fields. We use atomic force microscopy to both qualitatively and quantitatively study the orientation of antibodies on glass surfaces. We apply this ability for controlled orientation to enhance the performance of affinity-based assays. As a proof of concept, we use fluorescence detection to indirectly verify the modulation of the orientation of proteins bound to the surface. We studied the interaction of fluorescently tagged anti-IgG with surface immobilized IgG controlled by electric field. Our study demonstrates that the use of electric field can result in more than 100% enhancement in signal-to-noise ratio compared with normal physical adsorption.

  10. Tunable control of antibody immobilization using electric field

    PubMed Central

    Emaminejad, Sam; Javanmard, Mehdi; Gupta, Chaitanya; Chang, Shuai; Davis, Ronald W.; Howe, Roger T.

    2015-01-01

    The controlled immobilization of proteins on solid-state surfaces can play an important role in enhancing the sensitivity of both affinity-based biosensors and probe-free sensing platforms. Typical methods of controlling the orientation of probe proteins on a sensor surface involve surface chemistry-based techniques. Here, we present a method of tunably controlling the immobilization of proteins on a solid-state surface using electric field. We study the ability to orient molecules by immobilizing IgG molecules in microchannels while applying lateral fields. We use atomic force microscopy to both qualitatively and quantitatively study the orientation of antibodies on glass surfaces. We apply this ability for controlled orientation to enhance the performance of affinity-based assays. As a proof of concept, we use fluorescence detection to indirectly verify the modulation of the orientation of proteins bound to the surface. We studied the interaction of fluorescently tagged anti-IgG with surface immobilized IgG controlled by electric field. Our study demonstrates that the use of electric field can result in more than 100% enhancement in signal-to-noise ratio compared with normal physical adsorption. PMID:25650429

  11. Preparation of magnetite-fullerene nanocomposite with enzyme immobilization.

    PubMed

    Kalska-Szostko, B; Rogowska, M

    2012-09-01

    This study presents modification of magnetite nanoparticles and fullerene for biocompatibility. It show also specific fabrication of magnetite-carbon nanocomposite with immobilized biomolecule. The composites were created by joining individual components step-by-step manner (fullerene to magnetite and glucose oxidase or glucose oxidase to magnetite and fullerene). The resulting nanocomposites were characterized by infrared spectroscopy (IR) and transmission electron microscopy (TEM).

  12. Erosion depth of sand from an immobile gravel bed

    USDA-ARS?s Scientific Manuscript database

    Abstract This study was conducted to provide information on the depth of erosion of sand (D50 = 0.3, 0.9 mm) from immobile gravel (D50 = 36.1 mm) under steady uniform flows with bed shear stresses from 0.1 to 0.9 of that required to entrain the gravel. This situation, often encountered downstream o...

  13. Stabilization of α-amylase by using anionic surfactant during the immobilization process

    NASA Astrophysics Data System (ADS)

    El-Batal, A. I.; Atia, K. S.; Eid, M.

    2005-10-01

    This work describes the entrapment of α-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using γ irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized α-amylase were studied. Covering of α-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized α-amylase was increased below the critical micelle concentration (cmc) (10 mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized α-amylase showed a higher k/K and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of α-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems.

  14. Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils

    NASA Astrophysics Data System (ADS)

    Hanvey, S.; Glegg, M.; Foster, J.

    2009-09-01

    This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

  15. Immobilization of Streptomyces thermotolerans 11432 on polyurethane foam to improve production of acetylisovaleryltylosin.

    PubMed

    Zhu, Hongji; Wang, Weihua; Liu, Jiaheng; Caiyin, Qinggele; Qiao, Jianjun

    2015-01-01

    In this study, polyurethane foam (PUF) was chemically treated to immobilize Streptomyces thermotolerans 11432 for semi-continuous production of acetylisovaleryltylosin (AIV). Based on experimental results, positive cross-linked PUF (PCPUF) was selected as the most effective carrier according to immobilized cell mass. The effect of adsorption time on immobilized mass was investigated. AIV concentration (33.54 mg/l) in batch fermentations with immobilized cells was higher than with free cells (20.34 mg/l). In repeated batch fermentations with immobilized S. thermotolerans 11432 using PCPUF cubes, high AIV concentrations and conversion rates were attained, ranging from 25.56 to 34.37 mg/l and 79.93 to 86.31 %, respectively. Significantly, this method provides a feasible strategy for efficient AIV production and offers the potential for large-scale production.

  16. Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils.

    PubMed

    Hanvey, S; Glegg, M; Foster, J

    2009-09-21

    This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

  17. Immobilization of bacterial proteases on water-solved polymer by means of electron beam

    NASA Astrophysics Data System (ADS)

    Gonchar, A. M.; Auslender, V. L.

    1996-12-01

    Possibility of electron beam usage for proteases' immobilization on 1,4-polyalkylene oxide (1,4-PAO) was studied to obtain biologically active complex for multi-purpose usage. It is shown that immobilization of Bacillus Subtilis protease takes place due to free-radical linking of enzyme and carrier with formation of mycellium-like structures. Immobilization improves heat resistance of enzyme up to 60°C without substrate and up to 80°C in presence of substrate, widens range of pH activity in comparison with non-immobilized forms. Immobilized proteases do not contain peroxides or long-live radicals. Our results permitted to create technologies for production of medical and veterinary preparations, active components for wool washing agents and leather fabrication technology.

  18. Immobilization of a Bacterial Cytochrome P450 Monooxygenase System on a Solid Support.

    PubMed

    Tan, Cheau Yuaan; Hirakawa, Hidehiko; Suzuki, Risa; Haga, Tomoaki; Iwata, Fumiya; Nagamune, Teruyuki

    2016-11-21

    Bacterial cytochrome P450s (P450s), which catalyze regio- and stereoselective oxidations of hydrocarbons with high turnover rates, are attractive biocatalysts for fine chemical production. Enzyme immobilization is needed for cost-effective industrial manufacturing. However, immobilization of P450s is difficult because electron-transfer proteins are involved in catalysis and anchoring these can prevent them from functioning as shuttle molecules for carrying electrons. We studied a heterotrimeric protein-mediated co-immobilization of a bacterial P450, and its electron-transfer protein and reductase. Fusion with subunits of a heterotrimeric Sulfolobus solfataricus proliferating cell nuclear antigen (PCNA) enabled immobilization of the three proteins on a solid support. The co-immobilized enzymes catalyzed monooxygenation because the electron-transfer protein fused to PCNA via a single peptide linker retained its electron-transport function.

  19. Effect of consecutive cooling and immobilization on catecholamine metabolism in rat tissues

    NASA Technical Reports Server (NTRS)

    Matlina, E. S.; Waysman, S. M.; Zaydner, I. G.; Kogan, B. M.; Nozdracheva, L. V.

    1979-01-01

    The combined effect of two stressor stimuli--cooling and immobilization--acting successively on the sympathetic-adrenaline system was studied experimentally in rats that were cooled for 8 hours at 7 C on the first day and immobilized for 6 hours on the next day. The biochemical and histochemical methods used and the experimental technique involved are described in detail. The following conclusions were formulated: (1) the successive action of cooling and immobilization results in a stronger decrease in the adrenaline and noradrenaline content in the adrenal gland than that which could be due to a simple summation of the cooling and immobilization effects; (2) successive cooling and immobilization are followed by activation of catecholamine synthesis in the adrenal gland; and (3) 1-DOPA administration (45 mg/kg 3 times in 2 days) intraabdominally activated catecholamine synthesis in the adrenal glands in both the control and test animals.

  20. Enhanced activity of immobilized dimethylmaleic anhydride-protected poly- and monoclonal antibodies.

    PubMed

    Hadas, E; Koppel, R; Schwartz, F; Raviv, O; Fleminger, G

    1990-06-27

    The effect of reversible protection of the free amino groups of poly- and monoclonal antibodies by dimethylmaleic anhydride on their binding activity following immobilization onto various carriers was studied. The treatment with dimethylmaleic anhydride resulted in a 1.6-1.8-fold increase in the activity of immobilized goat anti-mouse immunoglobulin antibody immobilized onto different epoxy containing carriers and a 3-10.7-fold increase in the activity of immobilized monoclonal antibodies specific for carboxypeptidase A. The increase in activity was most pronounced at low antigen to carrier loads and over a wide range of modifier to protein ratios. The application of reversible protection of antibodies may permit the development of highly active immobilized antibody preparations for use in immunoaffinity purification.

  1. Optimization of catechol production by membrane-immobilized polyphenol oxidase: a modeling approach.

    PubMed

    Boshoff, A; Burton, M H; Burton, S G

    2003-07-05

    Although previous research has focused on phenol removal efficiencies using polyphenol oxidase in nonimmobilized and immobilized forms, there has been little consideration of the use of polyphenol oxidase in a biotransformation system for the production of catechols. In this study, polyphenol oxidase was successfully immobilized on various synthetic membranes and used to convert phenolic substrates to catechol products. A neural network model was developed and used to model the rates of substrate utilization and catechol production for both nonimmobilized and immobilized polyphenol oxidase. The results indicate that the biotransformation of the phenols to their corresponding catechols was strongly influenced by the immobilization support, resulting in differing yields of catechols. Hydrophilic membranes were found to be the most suitable immobilization supports for catechol production. The successful biocatalytic production of 3-methylcatechol, 4-methylcatechol, catechol, and 4-chlorocatechol is demonstrated.

  2. Fabrication of anticoagulation layer on titanium surface by sequential immobilization of poly (ethylene glycol) and albumin.

    PubMed

    Pan, Chang-Jiang; Hou, Yan-Hua; Zhang, Bin-Bin; Zhang, Lin-Cai

    2014-01-01

    This paper presents a simple method to sequentially immobilize poly (ethylene glycol) (PEG) and albumin on titanium surface to enhance the blood compatibility. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis indicated that PEG and albumin were successfully immobilized on the titanium surface. Water contact angle results showed a better hydrophilic surface after the immobilization. The immobilized PEG or albumin can not only obviously prevent platelet adhesion and activation but also prolong activated partial thromboplastin time (APTT), leading to the improved anticoagulation. Moreover, immobilization of albumin on PEG-modified surface can further improve the anticoagulation. The approach in the present study provides an effective and efficient method to improve the anticoagulation of blood-contact biomedical devices such as coronary stents.

  3. Immobilization of a Plant Lipase from Pachira aquatica in Alginate and Alginate/PVA Beads

    PubMed Central

    Bonine, Bárbara M.; Polizelli, Patricia Peres; Bonilla-Rodriguez, Gustavo O.

    2014-01-01

    This study reports the immobilization of a new lipase isolated from oleaginous seeds of Pachira aquatica, using beads of calcium alginate (Alg) and poly(vinyl alcohol) (PVA). We evaluated the morphology, number of cycles of reuse, optimum temperature, and temperature stability of both immobilization methods compared to the free enzyme. The immobilized enzymes were more stable than the free enzyme, keeping 60% of the original activity after 4 h at 50°C. The immobilized lipase was reused several times, with activity decreasing to approximately 50% after 5 cycles. Both the free and immobilized enzymes were found to be optimally active between 30 and 40°C. PMID:24818012

  4. Cellulases immobilization on chitosan-coated magnetic nanoparticles: application for Agave Atrovirens lignocellulosic biomass hydrolysis.

    PubMed

    Sánchez-Ramírez, Jaquelina; Martínez-Hernández, José L; Segura-Ceniceros, Patricia; López, Guillermo; Saade, Hened; Medina-Morales, Miguel A; Ramos-González, Rodolfo; Aguilar, Cristóbal N; Ilyina, Anna

    2017-01-01

    In the present study, Trichoderma reesei cellulase was covalently immobilized on chitosan-coated magnetic nanoparticles using glutaraldehyde as a coupling agent. The average diameter of magnetic nanoparticles before and after enzyme immobilization was about 8 and 10 nm, respectively. The immobilized enzyme retained about 37 % of its initial activity, and also showed better thermal and storage stability than free enzyme. Immobilized cellulase retained about 80 % of its activity after 15 cycles of carboxymethylcellulose hydrolysis and was easily separated with the application of an external magnetic field. However, in this reaction, K m was increased eight times. The immobilized enzyme was able to hydrolyze lignocellulosic material from Agave atrovirens leaves with yield close to the amount detected with free enzyme and it was re-used in vegetal material conversion up to four cycles with 50 % of activity decrease. This provides an opportunity to reduce the enzyme consumption during lignocellulosic material saccharification for bioethanol production.

  5. A Versatile Microarray Immobilization Strategy Based on a Biorthogonal Reaction Between Tetrazine and Trans-Cyclooctene.

    PubMed

    Wang, Ping; Gao, Liqian; Lei, Haipeng; Lee, Su Seong; Yao, Shao Q; Sun, Hongyan

    2017-01-01

    Given its increasing importance in transforming biomedical research in recent years, microarray technology has become highly popular as a powerful screening platform in detecting biomolecule interactions, discovering new inhibitors, and identifying biomarkers as well as diagnosing disease. The success of microarray technology in various biological applications is highly dependent on the accessibility, the functionality, and the density of the surface bound biomolecules. Therefore, compound immobilization represents a critical step for the successful implementation of microarray screening. Herein we describe a fast and site-specific microarray immobilization approach by using trans-cyclooctene-tetrazine ligation. This approach not only ensures fast immobilization and uniform display of biomolecules, but also allows the optimum orientation of biomolecules after immobilization. All these excellent properties facilitate subsequent interactions of the biomolecules and their interacting partners during the screening process. We envision that the immobilization strategy described here can find useful applications in many other microarray related studies.

  6. Pineapple stem bromelain immobilized on different supports: catalytic properties in model wine.

    PubMed

    Ilaria, Benucci; Marco, Esti; Katia, Liburdi; Maria Vittoria, Garzillo Anna

    2012-01-01

    Bromelain from pineapple stem has been covalently immobilized on different supports to select the more efficient biocatalyst that should be applied toward unstable proteins in real white wine. In this preliminary study, catalytic properties of different immobilized bromelain forms were compared under wine-like conditions, against a synthetic substrate (Bz-Phe-Val-Arg-pNA).Covalent immobilization affected protease kinetic properties, even if all immobilized forms presented both a better substrate affinity and higher half-life (with the exception of a few procedures) with respect to the free enzyme. Stem bromelain was successfully immobilized on chitosan beads without glutaraldehyde thus yielding a food-safe and promising biocatalyst for unstable real wine future application.

  7. Covalent attachment of cholesterol oxidase and horseradish peroxidase on perlite through silanization: activity, stability and co-immobilization.

    PubMed

    Torabi, Seyed-Fakhreddin; Khajeh, Khosro; Ghasempur, Salehe; Ghaemi, Nasser; Siadat, Seyed-Omid Ranaei

    2007-08-31

    In the present work, co-immobilization of cholesterol oxidase (COD) and horseradish peroxidase (POD) on perlite surface was attempted. The surface of perlite were activated by 3-aminopropyltriethoxysilane and covalently bonded with COD and POD via glutaraldehyde. Enzymes activities have been assayed by spectrophotometric technique. The stabilities of immobilized COD and POD to pH were higher than those of soluble enzymes and immobilization shifted optimum pH of enzymes to the lower pH. Heat inactivation studies showed improved thermostability of the immobilized COD for more than two times, but immobilized POD was less thermostable than soluble POD. Also activity recovery of immobilized COD was about 50% since for immobilized POD was 11%. The K(m) of immobilized enzymes was found slightly lower than that of soluble enzymes. Immobilized COD showed inhibition in its activity at high cholesterol concentration which was not reported for soluble COD before. Co-immobilized enzymes retained 65% of its initial activity after 20 consecutive reactor batch cycles.

  8. Effect of low-level helium-neon laser therapy on histological and ultrastructural features of immobilized rabbit articular cartilage.

    PubMed

    Bayat, Mohammad; Ansari, Enayatallah; Gholami, Narges; Bayat, Aghdas

    2007-05-25

    The present study investigates whether low-level helium-neon laser therapy can increase histological parameters of immobilized articular cartilage in rabbits or not. Twenty five rabbits were divided into three groups: the experiment group, which received low-level helium-neon laser therapy with 13J/cm(2) three times a week after immobilization of their right knees; the control group which did not receive laser therapy after immobilization of their knees; and the normal group which received neither immobilization nor laser therapy. Histological and electron microscopic examinations were performed at 4 and 7 weeks after immobilization. Depth of the chondrocyte filopodia in four-week immobilized experiment group, and depth of articular cartilage in seven-week immobilized experiment group were significantly higher than those of relevant control groups (exact Fisher test, p=0.001; student's t-test, p=0.031, respectively). The surfaces of articular cartilages of the experiment group were relatively smooth, while those of the control group were unsmooth. It is therefore concluded that low-level helium-neon laser therapy had significantly increased the depth of the chondrocyte filopodia in four-week immobilized femoral articular cartilage and the depth of articular cartilage in seven-week immobilized knee in comparison with control immobilized articular cartilage.

  9. Effect of temperature and mixing speed on immobilization of crude enzyme from Aspergillus niger on chitosan for hydrolyzing cellulose

    NASA Astrophysics Data System (ADS)

    Hamzah, Afan; Gek Ela Kumala, P.; Ramadhani, Dwi; Maziyah, Nurul; Rahmah, Laila Nur; Soeprijanto, Widjaja, Arief

    2017-05-01

    Conversion of cellulose into reducing sugar through enzymatic hydrolysis has advantageous because it produces greater product yield, higher selectivity, require less energy, more moderate operating conditions and environment friendly. However, the nature of the enzyme that is difficult to separate and its expensive price become an obstacle. These obstacles can be overcome by immobilizing the enzyme on chitosan material so that the enzyme can be reused. Chitosan is chosen because it is cheap, inert, hydrophilic, and biocompatible. In this research, we use covalent attachment and combination between covalent attachment and cross-linking method for immobilizing crude enzyme. This research was focusing in study of Effect of temperature and mixing speed on Immobilization Enzyme From Aspergillus Niger on Chitosan For Hydrolyzing both soluble (Carboxymethylcellulose) and insoluble Cellulose (coconut husk). This Research was carried out by three main step. First, coconut husk was pre-treated mechanically and chemically, Second, Crude enzyme from Aspergillus niger strain was immobilized on chitosan in various immobilization condition. At last, the pre-treated coconut husk and Carboxymetylcellulose (CMC) were hydrolyzed by immobilized cellulose on chitosan for reducing sugar production. The result revealed that the most reducing sugar produced by immobilized enzyme on chitosan+GDA with immobilization condition at 30 °C and 125 rpm. Enzyme immobilized on chitosan cross-linked with GDA produced more reducing sugar from preteated coconut husk than enzyme immobilized on chitosan.

  10. Optimizing immobilization on two-dimensional carboxyl surface: pH dependence of antibody orientation and antigen binding capacity.

    PubMed

    Pei, Zhichao; Anderson, Henrik; Myrskog, Annica; Dunér, Gunnar; Ingemarsson, Björn; Aastrup, Teodor

    2010-03-15

    The performance of immunosensors is highly dependent on the amount of immobilized antibodies and their remaining antigen binding capacity. In this work, a method for immobilization of antibodies on a two-dimensional carboxyl surface has been optimized using quartz crystal microbalance biosensors. We show that successful immobilization is highly dependent on surface pK(a), antibody pI, and pH of immobilization buffer. By the use of EDC/sulfo-NHS (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysulfosuccinimide) activation reagents, the effect of the intrinsic surface pK(a) is avoided and immobilization at very low pH is therefore possible, and this is important for immobilization of acidic proteins. Antigen binding capacity as a function of immobilization pH was studied. In most cases, the antigen binding capacity followed the immobilization response. However, the antigen-to-antibody binding ratio differed between the antibodies investigated, and for one of the antibodies the antigen binding capacity was significantly lower than expected from immobilization in a certain pH range. Tests with anti-Fc and anti-Fab(2) antibodies on different antibody surfaces indicated that the orientation of the antibodies on the surface had a profound effect on the antigen binding capacity of the immobilized antibodies. Copyright (c) 2009 Elsevier Inc. All rights reserved.

  11. Cascade catalysis in membranes with enzyme immobilization for multi-enzymatic conversion of CO2 to methanol.

    PubMed

    Luo, Jianquan; Meyer, Anne S; Mateiu, R V; Pinelo, Manuel

    2015-05-25

    Facile co-immobilization of enzymes is highly desirable for bioconversion methods involving multi-enzymatic cascade reactions. Here we show for the first time that three enzymes can be immobilized in flat-sheet polymeric membranes simultaneously or separately by simple pressure-driven filtration (i.e. by directing membrane fouling formation), without any addition of organic solvent. Such co-immobilization 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 activity was fully retained by this non-covalent immobilization strategy. The two immobilization systems had similar catalytic efficiencies because the second reaction (formic acid→formaldehyde) catalyzed by FaldDH was found to be the cascade bottleneck (a threshold substrate concentration was required). Moreover, the trade-off between the mitigation of product inhibition and low substrate concentration for the adjacent enzymes probably made the co-immobilization meaningless. Thus, sequential immobilization could be used for multi-enzymatic cascade reactions, as it allowed the operational conditions for each single step to be optimized, not only during the enzyme immobilization but also during the reaction process, and the pressure-driven mass transfer (flow-through mode) could overcome the diffusion resistance between enzymes. This study not only offers a green and facile immobilization method for multi-enzymatic cascade systems, but also reveals the reaction bottleneck and provides possible solutions for the bioconversion of CO2 to methanol.

  12. Technetium Immobilization Forms Literature Survey

    SciTech Connect

    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.

  13. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO₂ nanoparticles from aqueous media.

    PubMed

    Shaker, Medhat A; Yakout, Amr A

    2016-02-05

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, (1)H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r(2)) and non-linear Chi-square (χ(2)) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Drug absorption in vitro model: filter-immobilized artificial membranes. 2. Studies of the permeability properties of lactones in Piper methysticum Forst.

    PubMed

    Avdeef, A; Strafford, M; Block, E; Balogh, M P; Chambliss, W; Khan, I

    2001-12-01

    The assessment of transport properties of 23 drug and natural product molecules was made using the in vitro model based on filter-immobilized artificial membranes (filter-IAM), assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 h). The highly mobile kava lactones permeated in the order dihydromethisticin (40)>yangonin (37)>kavain (34)>methisticin (32)>desmethoxyyangonin (26), the numbers in parentheses being the measured effective permeabilities in units of 10(-6) cm/s. By comparison, commercial drugs ranked: phenazopyridine (35)>testosterone (19)>propranolol (13)>ketoconazole (6.3)>piroxicam (2.2)>caffeine (1.7)>metoprolol (0.8)>terbutaline (0.01). In addition to permeability measurements, membrane retention of compounds was determined. Yangonin, desmethoxyyangonin, ketoconazole, and phenazopyridine were more than 60% retained by the artificial membranes containing phospholipids. Stirring during assay significantly increased the observed permeabilities for highly mobile molecules, but had minimal impact on the poorly permeable molecules. The influence of hydrogen bonding was explored by determining permeabilities using filters coated with dodecane free of phospholipids. In the filter-IAM method, concentrations were determined by microtitre plate UV spectrophotometry and by LC-MS. Higher-throughput was achieved with direct UV by the use of 96-well microtitre plate formats and with LC-MS by the use of cassette dosing (five-in-one).

  15. Evaluation of meat and bone meal combustion residue as lead immobilizing material for in situ remediation of polluted aqueous solutions and soils: "chemical and ecotoxicological studies".

    PubMed

    Deydier, E; Guilet, R; Cren, S; Pereas, V; Mouchet, F; Gauthier, L

    2007-07-19

    As a result of bovine spongiform encephalopathy (BSE) crisis, meat and bone meal (MBM) production can no longer be used to feed cattle and must be safely disposed of or transformed. MBM specific incineration remains an alternative that could offer the opportunity to achieve both thermal valorization and solid waste recovery as ashes are calcium phosphate-rich material. The aim of this work is to evaluate ashes efficiency for in situ remediation of lead-contaminated aqueous solutions and soils, and to assess the bioavailability of lead using two biological models, amphibian Xenopus laevis larvae and Nicotiana tabaccum tobacco plant. With the amphibian model, no toxic or genotoxic effects of ashes are observed with concentrations from 0.1 to 5 g of ashes/L. If toxic and genotoxic effects of lead appear at concentration higher than 1 mg Pb/L (1 ppm), addition of only 100 mg of ashes/L neutralizes lead toxicity even with lead concentration up to 10 ppm. Chemical investigations (kinetics and X-ray diffraction (XRD) analysis) reveals that lead is quickly immobilized as pyromorphite [Pb10(PO4)6(OH)2] and lead carbonate dihydrate [PbCO(3).2H2O]. Tobacco experiments are realized on contaminated soils with 50, 100, 2000 and 10000 ppm of lead with and without ashes amendment (35.3g ashes/kg of soil). Tobacco measurements show that plant elongation is bigger in an ashes-amended soil contaminated with 10000 ppm of lead than on the reference soil alone. Tobacco model points out that ashes present two beneficial actions as they do not only neutralize lead toxicity but also act as a fertilizer.

  16. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

    NASA Astrophysics Data System (ADS)

    Shaker, Medhat A.; Yakout, Amr A.

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51 ± 3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  17. 3D-Printed Small-Animal Immobilizer for Use in Preclinical Radiotherapy.

    PubMed

    McCarroll, Rachel E; Rubinstein, Ashley E; Kingsley, Charles V; Yang, Jinzhong; Yang, Peiying; Court, Laurence E

    2015-09-01

    We have designed a method for immobilizing the subjects of small-animal studies using a study group-specific 3D-printed immobilizer that significantly reduces interfraction rotational variation. A cone-beam CT scan acquired from a single specimen in a study group was used to create a 3D-printed immobilizer that can be used for all specimens in the same study group. 3D printing allows for the incorporation of study-specific features into the immobilizer design, including geometries suitable for use in MR and CT scanners, holders for fiducial markers, and anesthesia nose cones of various sizes. Using metrics of rotational setup variations, we compared the current setup in our small-animal irradiation system, a half-pipe bed, with the 3D-printed device. We also assessed translational displacement within the immobilizer. The printed design significantly reduced setup variation, with average reductions in rotational displacement of 76% ± 3% (1.57 to 0.37°) in pitch, 78% ± 3% (1.85 to 0.41°) in yaw, and 87% ± 3% (5.39 to 0.70°) in roll. Translational displacement within the printed immobilizer was less than 1.5 ± 0.3 mm. This method of immobilization allows for repeatable setup when using MR or CT scans for the purpose of radiotherapy, streamlines the workflow, and places little burden on the study subjects.

  18. Plutonium Immobilization Can Loading Equipment Review

    SciTech Connect

    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.

  19. Helicopter immobilization of elk in southcentral Washington

    SciTech Connect

    McCorquodale, S.M.; Eberhardt, L.E. ); Petron, S.E. )

    1988-01-01

    Free-ranging elk are commonly immobilized for research or management by rifle-fired darts shot from a helicopter. Compounds used for this purpose have included succinylcholine chloride (succinylcholine), etorphine hydrochloride (etorphine), and xylazine hydrochloride (xylazine). To assess the efficacy of various immobilizing drugs used in helicopter applications, we darted 38 elk from a helicopter on the Arid Lands Ecology Reserve, Washington from 1983 to 1987. We used either succinylcholine, etorphine hydrochloride, or xylazine hydrochloride a primary immobilants. Unsuccessful immobilizations were most common in elk darted with succinylcholine. Yohimbine was used to reverse xylazine immobilizations. The use of xylazine and yohimbine provides an efficient, cost-effective alternative to etorphine, diprenorphine immobilization and reversal in elk while increasing handler safety. Etorphine appeared to be the best immobilant when extended pain-producing procedures (such as surgical telemetry implantation) are planned because it induced the longest and deepest anesthesia. When the potential to lose contact with darted animals exist, we believe succinylcholine may be the preferred immobilant because of rapid, spontaneous recovery.

  20. Immobilization of enzyme on chiral polyelectrolyte surface.

    PubMed

    Ding, Chao; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2017-02-01

    Chiral D- and L-N-acryloyl aspartic acid (NAsp) polyelectrolyte (PE) surfaces with similar chemical compositions and physical properties but opposite chirality are designed for enzyme immobilization. Enzymes immobilized onto the chiral PE surfaces present high chiral preference, namely L-NAsp PE surface can keep most of the catalytic activity of the immobilized enzymes, however, for enzymes immobilized on D-NAsp PE surface a large decrease in catalytic activity occurred which was 11 times lower compared with L-NAsp PE surface. This phenomenon of chiral effect on enzymes immobilization can be explained by attenuated total reflectance (ATR) and circular dichroism (CD) results. The results exhibited that L-NAsp PE surface could preserve most of the secondary structures of immobilized enzymes while on D-NAsp PE surface with a large conformation alteration. These chiral surface induced differences after enzyme immobilization can be further used for logic operation. These results imply a novel strategy for the design of new enzymes immobilization materials based on the chiral effect and expand the applications of enzymes in biochips, chemical transformations and chiral biodevices.

  1. Drug immobilization of walrus (Odobenus rosmarus)

    USGS Publications Warehouse

    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.

  2. Surface and Interface Control on Photochemically Initiated Immobilization

    SciTech Connect

    Liu, Li; Engelhard, Mark H.; Yan, Mingdi

    2006-11-01

    Surface and interface properties are important in controlling the yield and efficiency of the photochemically initiated immobilization. Using a silane-functionalized perfluorophenylazide (PFPA-silane) as the photoactive crosslinker, the immobilization of polymers was studied by adjusting the density of the surface azido groups. Dilution of the photolinker resulted in a gradual decrease in the density of surface azido groups as well as the thickness of the immobilized film. When a non-photoactive silane was added to PFPA-silane, the film thickness decreased more rapidly, indicating that the additive competed with PFPA-silane and effectively reduced the density of the surface azido groups. The effect of surface topography was studied by adding a non-photoactive silane with either a shorter (n-propyltrimethoxysilane (PTMS)) or a longer spacer (n-octadecyltrimethoxysilane (ODTMS)). In most cases the long chain ODTMS shielded the surface azido groups resulting in more rapid decrease in film thickness as compared to PTMS treated under the same conditions. As the density of the surface azido groups decreased, the immobilized polymer changed from smooth films to patched structures, and eventually single polymer molecules.

  3. Leukocyte responses to immobilized patterns of CXCL8.

    PubMed

    Girrbach, Maria; Rink, Ina; Ladnorg, Tatjana; Azucena, Carlos; Heißler, Stefan; Haraszti, Tamás; Schepers, Ute; Schmitz, Katja

    2016-06-01

    The attachment of neutrophils to the endothelial surface and their migration towards the site of inflammation following chemokine gradients play an essential role in the innate immune response. Chemokines adhere to glycosaminoglycans on the endothelial surface to be detected by leukocytes and trigger their movement along surface- bound gradients in a process called haptotaxis. In assays to systematically study the response of leukocytes to surface-bound compounds both the spatial arrangement of the compound as well as the mode of immobilization need to be controlled. In this study microcontact printing was employed to create patterns of hydrophobic or functionalized thiols on gold-coated glass slides and CXCL8 was immobilized on the thiol coated areas using three different strategies. Human neutrophils adhered to the CXCL8-coated lines but not to the PEG-coated background. We could show that more cells adhered to CXCL8 adsorbed to hydrophobic octadecanethiol than on CXCL8 covalently bound to amino undecanethiol or CXCL8 specifically bound to immobilized heparin on aminothiol. Likewise general cell activity such as lamellipodia formation and random migration were most pronounced for CXCL8 adsorbed on a hydrophobic surface which may be attributed to the larger amounts of protein immobilized on this type of surface.

  4. Immobilization of microalgae for biosorption and degradation of butyltin chlorides.

    PubMed

    Zhang, L; Huang, G; Yu, Y

    1998-07-01

    Since the discovery of their biocidal properties in the 1950s, organotin compounds have found a large spectrum of industrial applications such as wood and textile preservatives, fungicides and pesticides, and antifouling paint on ships and fishing equipment. The fate and environmental impact of butyltins have been the subjects of a large body of research in the last decades. Biosorption and degradation of butyltin compounds by immobilized microalgae chlorella were studied in this paper, aiming to find an alternative way to solve organotin pollution problem. Chlorella emersonii cells were entrapped in a calcium aginate matrix. The cell growth rates, respiratory rate and chlorophyll a content were studied and compared. Results showed that immobilized chlorella had increased respiratory and growth rates, and almost equal chlorophyll a content when compared with free cells. Cell leakage was slight during the 20-day experimental period Cell leakage from the matrix was unrelated to cell growth within the matrix. Immobilized chlorella was applied to deal with butytin contaminated aquatic solutions. Immobilized chlorella had increased degradation rates of tri-, di-, and mono-butyltin chlorides in aquatic solutions, and lower biological accumulation factors on cells, than free cells, which indicates a potential use for tackleing organotin polluted water body.

  5. Substrate specificity and enzyme recycling using chitosan immobilized laccase.

    PubMed

    Skoronski, Everton; Fernandes, Mylena; Magalhães, Maria de Lourdes Borba; da Silva, Gustavo Felippe; João, Jair Juarez; Soares, Carlos Henrique Lemos; Júnior, Agenor Fúrigo

    2014-10-17

    The immobilization of laccase (Aspergillus sp.) on chitosan by cross-linking and its application in bioconversion of phenolic compounds in batch reactors were studied. Investigation was performed using laccase immobilized via chemical cross-linking due to the higher enzymatic operational stability of this method as compared to immobilization via physical adsorption. To assess the influence of different substrate functional groups on the enzyme's catalytic efficiency, substrate specificity was investigated using chitosan-immobilized laccase and eighteen different phenol derivatives. It was observed that 4-nitrophenol was not oxidized, while 2,5-xylenol, 2,6-xylenol, 2,3,5-trimethylphenol, syringaldazine, 2,6-dimetoxyphenol and ethylphenol showed reaction yields up 90% at 40 °C. The kinetic of process, enzyme recyclability and operational stability were studied. In batch reactors, it was not possible to reuse the enzyme when it was applied to syringaldazne bioconversion. However, when the enzyme was applied to bioconversion of 2,6-DMP, the activity was stable for eight reaction batches.

  6. Immobilized Lactase in the Biochemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Allison, Matthew J.; Bering, C. Larry

    1998-10-01

    Immobilized enzymes have many practical applications. They may be used in clinical, industrial, and biotechnological laboratories and in many clinical diagnostic kits. For educational purposes, use of immobilized enzymes can easily be taught at the undergraduate or even secondary level. We have developed an immobilized enzyme experiment that combines many practical techniques used in the biochemistry laboratory and fits within a three-hour time frame. In this experiment, lactase from over-the-counter tablets for patients with lactose intolerance is immobilized in polyacrylamide, which is then milled into small beads and placed into a chromatography column. A lactose solution is added to the column and the eluant is assayed using the glucose oxidase assay, available as a kit. We have determined the optimal conditions to give the greatest turnover of lactose while allowing the immobilized enzymes to be active for long periods at room temperature.

  7. Immobilization of whole cells using polymeric coatings

    SciTech Connect

    Lawton, C.W.; Klei, H.E.; Sunstrom, D.V.; Voronka, P.J.; Scott, C.D.

    1986-01-01

    A cell immobilization procedure was developed using latex coatings on solid particles. The method's widespread applicability has been demonstrated by successfully immobilizing Saccharomyces cerevisiae (ethanol production), Bacillus subtilis (tryptophan production). Penicillium chrysogenum (penicillin G production), and Escherichia coli (aspartic acid production). In contrast to other immobilization methods, this procedure produces a pellicular particle that is porous, allowing rapid substrate and gas transfer, has a hard core to avoid compression in large beds, and is dense to allow use in fluidized beds. The immobilization procedure was optimized with S. cerevisiae. Kinetic constants obtained were used to calculate effectiveness factors to show that there was minimal intraparticle diffusion resistance. Reactors utilizing the optimized particles were run for 300 hours to evaluate immobilized particle half-life which was 250 hours.

  8. Spine immobilization: prehospitalization to final destination.

    PubMed

    Kang, Daniel G; Lehman, Ronald A

    2011-01-01

    Care of the combat casualty with spinal column or spinal cord injury has not been previously described, particularly in regards to spinal immobilization. The ultimate goal of spinal immobilization in the combat casualty is to first ``do no further harm'' and then provide a stable, painless spine and an optimal neurologic recovery. The protocol for treatment of the combat casualty with suspected spinal column or spinal cord injury from the battlefield to final arrival at a definitive treatment center is discussed, and the special considerations for medical evacuation off the battlefield and for aeromedical transport are delineated. Selective prehospital spine immobilization, which involves spinal immobilization with backboard, semi-rigid cervical collar, lateral supports, and straps or tape, is recommended if there is suspicion of spinal column or spinal cord injury in the combat casualty and when conditions and resources permit. The authors do not recommend spinal immobilization for the combat casualty with isolated penetrating trauma.

  9. Immobilized fluid membranes for gas separation

    DOEpatents

    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.

  10. Effects of immobilization and whole-body vibration on rat serum Type I collagen turnover.

    PubMed

    Dönmez, Gürhan; Doral, Mahmut Nedim; Suljevic, Şenay; Sargon, Mustafa Fevzi; Bilgili, Hasan; Demirel, Haydar Ali

    2016-08-01

    The aim of this study was to investigate the effects of short-term, high-magnitude whole-body vibration (WBV) on serum type I collagen turnover in immobilized rats. Thirty Wistar albino rats were randomly divided into the following 5 groups: immobilization (IS), immobilization + remobilization (IR), immobilization + WBV (IV), control (C), and WBV control (CV). Immobilization was achieved by casting from the crista iliaca anterior superior to the lower part of the foot for 2 weeks. The applied WBV protocol involved a frequency of 45 Hz and amplitude of 3 mm for 7 days starting a day after the end of the immobilization period. Serum type I collagen turnover markers were measured by using ELISA kits. Serum NH2-terminal propeptide of type I collagen (PINP) levels were significantly lower in the immobilization groups (p < 0.02) compared with the control groups. Although WBV improved PINP levels in the control groups, there were no differences in PINP levels among the immobilization groups. Similarly, serum COOH-terminal telopeptide of type I collagen (CTX) levels were higher in the WBV controls than their own controls (p < 0,05). Immobilization led to deterioration of tendon tissue, as observed by histopathological analysis with a transmission electron microscope. Although 1 week of WBV had a positive effect on type I collagen turnover in controls, it is not an efficient method for repairing tissue damage in the early stage following immobilization. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  11. The effects of joint immobilization on articular cartilage of the knee in previously exercised rats

    PubMed Central

    Maldonado, Diogo Correa; da Silva, Marcelo Cavenaghi Pereira; Neto, Semaan El-Razi; Souza, Mônica Rodrigues; Souza, Romeu Rodrigues

    2013-01-01

    Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 μm, P < 0.05), but not in group EI (mean, 174 ± 2.25), and increased significantly in group E (mean, 289.49 ± 9.15) compared with group C (mean, 239.20 ± 6.25). The same results were obtained for cell density, nuclear size, and collagen density (in all cases, P < 0.05). We concluded that exercise can prevent degenerative changes in femoral articular cartilage caused by immobilization of the knee joint. PMID:23480127

  12. Synthesis, characterization of silica gel phases-chemically immobilized-4-aminoantipyrene and applications in the solid phase extraction, preconcentration and potentiometric studies.

    PubMed

    Osman, Mohamad M; Kholeif, Sherif A; Abou-Almaaty, Nevine A; Mahmoud, Mohamad E

    2004-05-01

    Two new 4-aminoantipyrene chemically-immobilized silica gel phases: ii (N,N-donor) and iii (N,O-donor), were synthesized and characterized by IR and surface coverage determination. The latter was accomplished by thermal desorption and metal probe methods, giving 0.300 and 0.312 mmol g(-1) for ii and 0.220 and 0.250 mmol g(-1) for iii. Moreover, potentiometric titration provided a surface coverage of 0.323 mmol g(-1) for ii. The metal capacity values in mmol g(-1) of ii, iii and the active silica gel phase i for a series of di- and trivalent metal ions were determined at pH 1.0 - 6.7. Phase i showed the lowest values, while ii and iii reflected higher affinity toward most of the metal ions. The highest values were 0.300 for Hg(II)-ii and 0.220 mmol g(-1) for Cd(II)-iii. Distribution coefficients (log Kd) were in the range of 3.57 - 4.76 for ii and 2.32 - 3.46 for iii, thus confirming certain selectivity characters of the solid extractors. The application of the phases as solid extractors and preconcentrators for some heavy metal ions is presented. Good percentage extraction and removal of 94 - 98 +/- 4 - 6% of the spiked 1.000 microg ml(-1) of Hg(II), Cd(II), Pb(II), Cu(II) and Zn(II) and good percentage recovery of 94 - 99 +/- 3 - 6% of 50 ng ml(-1) of these ions from tap water samples were obtained. Stability constants of H(I) and Cu(II) with ii for the two-phase mixture at 25 degrees C and I = 0.1 (KCI) were determined potentiometrically. The pKa of ii are 5.6 and 8.4, while the log K values for CuHL and CuL (L = ii) are 6.3 and 5.8, respectively, leading to the determination of several analytical data for Cu(II)-ii.

  13. Stability of immobilized yeast alcohol dehydrogenase

    SciTech Connect

    Ooshima, H.; Genko, Y.; Harano, Y.

    1981-12-01

    The effects of substrate on stabilities of native (NA) and three kinds of immobilized yeast alcohol dehydrogenase (IMA), namely PGA (the carrier; porous glass), SEA (agarose gel) prepared covalently, and AMA (anion-exchange resin) prepared ionically, were studied. The following results were obtained. 1) The deactivations of NA and IMA free from the substrate or in the presence of ethanol obey the first-order kinetics, whereas, in the presence of butyraldehyde, their deactivation behaviors are explained on the basis of coexistence of two components of YADHs, namely the labile E1 and the comparatively stable E2, with different first-order deactivation constants. (2) A few attempts for stabilization of IMA were carried out from the viewpoint of the effects of crosslinkages among the subunits of YADH for PGA and the multibonding between the carrier and enzyme for SEA. The former is effective for the stabilization, whereas the latter is not. (Refs. 19).

  14. Sperm immobilizing properties of lemon juice.

    PubMed

    Clarke, Gary N; McCoombe, Scott G; Short, Roger V

    2006-05-01

    The aim of this study was to evaluate the sperm-immobilizing properties of lemon juice to determine if they are consistent with its traditional contraceptive use. It was found that lemon juice supernatant (LJS) has high osmolality (550-60 mOsm) and low pH (2.2-2.6) and that addition of LJS to semen to give a final concentration of 20% v/v reduced the pH from around 8.4 to 4.1. This acidification was associated with irreversible cessation of all sperm movements within 1 minute. In conclusion, lemon juice should be further evaluated for acceptability, safety, and efficacy as a topical vaginal contraceptive agent.

  15. On-chip immobilization of planarians for in vivo imaging

    PubMed Central

    Dexter, Joseph P.; Tamme, Mary B.; Lind, Christine H.; Collins, Eva-Maria S.

    2014-01-01

    Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

  16. On-chip immobilization of planarians for in vivo imaging.

    PubMed

    Dexter, Joseph P; Tamme, Mary B; Lind, Christine H; Collins, Eva-Maria S

    2014-09-17

    Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra.

  17. Phosphate immobilization using an acidic type F fly ash.

    PubMed

    Grubb, D G; Guimaraes, M S; Valencia, R

    2000-09-15

    Batch equilibration experiments using a low calcium ( approximately 1 wt.% as CaO), acidic (pH approximately 4.5) Type F fly ash demonstrated phosphate immobilization on the order of 100% to 75% for 50 and 100 mg P/l solutions, respectively. A loosely compacted column of fly ash similarly removed 10 mg P/l for over 85 pore volumes. While the interactions between phosphate and calcium-rich (Type C) ashes are relatively well understood, insight into the mechanisms of phosphate immobilization in Type F ash necessitated a review of the phosphate chemistry and interactions with acidic geomedia. Phosphate adsorption was subsequently modeled using a constant capacitance model approach (CCM) excluding precipitation reactions. Our CCM predictions of total phosphate immobilization (20%) were substantially less than the results of the batch equilibration experiments and phosphate adsorption predicted by other researchers examining near pure natural and synthetic geomedia due to the compositional heterogeneity of the fly ash. Nevertheless, for the amorphous and crystalline phases studied, the immobilization of phosphate in the Type F fly ash is attributed to the formation of insoluble aluminum and iron phosphates at low to medium values of pH.

  18. Recent advances in covalent, site-specific protein immobilization

    PubMed Central

    Meldal, Morten; Schoffelen, Sanne

    2016-01-01

    The properties of biosensors, biomedical implants, and other materials based on immobilized proteins greatly depend on the method employed to couple the protein molecules to their solid support. Covalent, site-specific immobilization strategies are robust and can provide the level of control that is desired in this kind of application. Recent advances include the use of enzymes, such as sortase A, to couple proteins in a site-specific manner to materials such as microbeads, glass, and hydrogels. Also, self-labeling tags such as the SNAP-tag can be employed. Last but not least, chemical approaches based on bioorthogonal reactions, like the azide–alkyne cycloaddition, have proven to be powerful tools. The lack of comparative studies and quantitative analysis of these immobilization methods hampers the selection process of the optimal strategy for a given application. However, besides immobilization efficiency, the freedom in selecting the site of conjugation and the size of the conjugation tag and the researcher’s expertise regarding molecular biology and/or chemical techniques will be determining factors in this regard. PMID:27785356

  19. Immobilization of laccase of Pycnoporus sanguineus CS43.

    PubMed

    Gonzalez-Coronel, Luis A; Cobas, Marta; Rostro-Alanis, Magdalena de J; Parra-Saldívar, Roberto; Hernandez-Luna, Carlos; Pazos, Marta; Sanromán, M Ángeles

    2017-10-25

    Laccase from Pycnoporus sanguineus CS43 was successfully immobilized onto Immobead-150 and Eupergit-C by covalent binding and by entrapment in LentiKats. The highest immobilization was onto Immobead-150 (97.1±1.2%) compared to the other supports, LentiKats (89±1.1%) and Eupergit-C (83.2±1.4%). All three immobilized enzyme systems showed increased thermostability and better mechanical properties than free laccase. Moreover, after 5 cycles of reuse of these systems, 90% of initial laccase activity was retained. Immobead-150 and LentiKats systems exhibited the highest efficiencies in removal of m-cresol under the combined actions of biodegradation and adsorption, while laccase entrapped in LentiKats showed a high ability for degradation of m-cresol within 24h. In addition, the typical Michaelis-Menten enzymatic model effectively described the kinetic profile of m-cresol degradation by the enzyme entrapped in LentiKats. Based on the results obtained in the present study, it can be established that the immobilized biocatalysts developed here possess significant potential for wastewater treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Immobilization effects on the photocatalytic activity of CdS quantum Dots-Horseradish peroxidase hybrid nanomaterials.

    PubMed

    Iñarritu, Iker; Torres, Eduardo; Topete, Antonio; Campos-Terán, José

    2017-11-15

    The potential use of hybrid nanomaterials based on inorganic optically active nanoparticles known as quantum dots (QDs) and horseradish peroxidase (HRP) has been proposed by several authors as light-controllable nanocatalyzers, moreover, the immobilization within or over silica based supports represents an advantage over bulk-dispersed systems. However, the implications of the immobilization of such hybrid photoactivatable catalyzing systems have not been clarified with detail. Here, we present a thorough study of the functional photoactive efficiency and recycling of immobilized CdS QDs and HRP systems with different configurations, immobilized over silanized silica quartz crystal microbalance (QCM) sensors, allowing an accurate measure of the immobilized mass of each component and its correlation with the initial reaction rate of conversion of Amplex Red (AR) to resorufin. As well, the conversion efficiency is compared between the different systems and also to non-immobilized QD-HRP complexed systems. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Immobilization of indigenous holocellulase on iron oxide (Fe2O3) nanoparticles enhanced hydrolysis of alkali pretreated paddy straw.

    PubMed

    Kumar, Ajay; Singh, Surender; Tiwari, Rameshwar; Goel, Renu; Nain, Lata

    2017-03-01

    The holocellulase from Aspergillus niger SH3 was characterized and found to contain 125 proteins including cellulases (26), hemicellulases (21), chitinases (10), esterases (6), amylases (4) and hypothetical protein (32). The crude enzyme was immobilized on five different nanoparticles (NPs) via physical adsorption and covalent coupling methods. The enzyme-nanoparticle complexes (ENC) were screened for protein binding, enzymatic activities and immobilization efficiency. Magnetic enzyme-nanoparticle complexes (MENC) showed higher immobilization efficiency (60-80%) for most of the enzymes. MENC also showed better catalytic efficiencies in term of higher Vmax and lower Km than free enzyme. Saccharification yields from alkali treated paddy straw were higher (375.39mg/gds) for covalently immobilized MENC than free enzyme (339.99mg/gds). The immobilized enzyme was used for two cycles of saccharification with 55% enzyme recovery. Hence, this study for the first time demonstrated the immobilization of indigenous enzyme and its utilization for saccharification of paddy straw.

  2. Targeted Cell Immobilization by Ultrasound Microbeam

    PubMed Central

    Lee, Jungwoo; Lee, Changyang; Kim, Hyung Ham; Jakob, Anette; Lemor, Robert; Teh, Shia-Yen; Lee, Abraham; Shung, K. Kirk

    2011-01-01

    Various techniques exerting mechanical stress on cells have been developed to investigate cellular responses to externally controlled stimuli. Fundamental mechanotransduction processes, how applied physical forces are converted into biochemical signals, have often been examined by transmitting such forces through cells and probing its pathway at cellular levels. In fact, many cellular biomechanics studies have been performed by trapping (or immobilizing) individual cells, either attached to solid substrates or suspended in liquid media. In that context, we demonstrated two-dimensional acoustic trapping, where a lipid droplet of 125 μm in diameter was directed transversely towards the focus (or the trap center) similar to that of optical tweezers. Under the influence of restoring forces created by a 30 MHz focused ultrasound beam, the trapped droplet behaved as if tethered to the focus by a linear spring. In order to apply this method to cellular manipulation in the Mie regime (cell diameter > wavelength), the availability of sound beams with its beamwidth approaching cell size is crucial. This can only be achieved at a frequency higher than 100 MHz. We define ultrasound beams in the frequency range from 100 MHz to a few GHz as ultrasound microbeams because the lateral beamwidth at the focus would be in the micron range (reviewer #1). Hence a zinc oxide (ZnO) transducer that was designed and fabricated to transmit a 200 MHz focused sound beam was employed to immobilize a 10 μm human leukemia cell (K-562) within the trap. The cell was laterally displaced with respect to the trap center by mechanically translating the transducer over the focal plane. Both lateral displacement and position trajectory of the trapped cell were probed in a two-dimensional space, indicating that the retracting motion of these cells was similar to that of the lipid droplets at 30 MHz. The potential of this tool for studying cellular adhesion between white blood cells and endothelial cells

  3. Plutonium Immobilization Can Loading Concepts

    SciTech Connect

    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.

  4. Plutonium Immobilization Project Baseline Formulation

    SciTech Connect

    Ebbinghaus, B.

    1999-02-01

    A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.

  5. Ceramic Hosts for Fission Products Immobilization

    SciTech Connect

    Peter C Kong

    2010-07-01

    metal ions, Mg and Ca, in the ceramic host phases. The immobilization of rear earth (lanthanide series) fission products in these ceramic host phases will also be studied this year. Cerium oxide is chosen to represent the rear earth fission product for substitution studies in spinel, perovskite and zirconolite ceramic hosts. Cerium has +3 and +4 oxidation states and it can replace some of the trivalent or tetravalent host ions to produce the substitution ceramics such as MgAl2-xCexO4, CaTi1-xCexO3, CaZr1-xCexTi2O7 and CaZrTi2-xCexO7. X-ray diffraction analysis will be used to compare the crystalline structures of the pure ceramic hosts and the substitution phases. SEM-EDX analysis will be used to study the Ce distribution in the ceramic host phases. The range of cerium doping is planned to reach the full substitution of the trivalent or tetravalent ions, Al, Ti and Zr, in the ceramic host phases.

  6. Recycle use of immobilized glucoamylase by tangential flow filtration unit.

    PubMed

    Uttapap, D; Koba, Y; Ishizaki, A

    1989-01-25

    Various properties of glucoamylase immobilized onto corn stover supporting material and separation of immobilized enzyme by tangential flow filtration unit were studied. Optimum pH and temperature of immobilized enzyme were 3.5 and 60 degrees C, respectively. Enzyme stability was studied in a packed-bed column. The starch conversion rate was attained at 81% for 15 days; after that, the hydrolysis rate gradually decreased. Size of supporting material proved to be an important factor, with higher activity and good loading yield resulting from smaller supporting material. Glucoamylase immobilized onto supporting material less than 44 microm was used for hydrolysis of 10% soluble starch at pH 3.5 and 40 degrees C for 3 h. Then immobilized glucoamylase was separated from the product by means of a tangential flow filtration unit using a 0.2-microm pore size Nylon 66 membrane filter. This operation was continued until 180 ml filtrate was obtained from a 260-mL starting volume. Then, the next batch was started by adding 180 mL starch substrate into the reactor. The batchwise experiments were repeated 20 times. The average filtration rate of each batch was determined and found to sharply decline during the first four batches. Thereafter, it gradually decreased from batch to batch. The cause of decreasing filtration rate appeared to be due to retrogradation of starch. The percentage of starch hydrolysis within 20 batches was in the range 89-96%. The filtration rate becomes higher if the hydrolyzation time is extended to 14 h. Resistance to filtration was also investigated. Almost all of the total resistance is related to insoluble materials, with the significant part of this from the resistance due to insoluble materials deposited on a surface of membrane and boundary layer resistance. Using a microscopic method, no microorganisms were found in the filtrate.

  7. Recovery time course in contractile function of fast and slow skeletal muscle after hindlimb immobilization

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Kim, D. H.; Fitts, R. H.

    1982-01-01

    The present study was undertaken to characterize the time course and extent of recovery in the isometric and isotonic contractile properties of fast and slow skeletal muscle following 6 wk of hindlimb immobilization. Female Sprague-Dawley rats were randomly assigned to an immobilized group or a control group. The results of the study show that fast and slow skeletal muscles possess the ability to completely recover normal contractile function following 6 wk of hindlimb immobilization. The rate of recovery is dependent on the fiber type composition of the affected muscle.

  8. Effect of Sulfonylureas Administered Centrally on the Blood Glucose Level in Immobilization Stress Model

    PubMed Central

    Sharma, Naveen; Sim, Yun-Beom; Park, Soo-Hyun; Lim, Su-Min; Kim, Sung-Su; Jung, Jun-Sub; Hong, Jae-Seung

    2015-01-01

    Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level. PMID:25954123

  9. Activity of Laccase Immobilized on TiO2-Montmorillonite Complexes

    PubMed Central

    Wang, Qingqing; Peng, Lin; Li, Guohui; Zhang, Ping; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2013-01-01

    The TiO2-montmorillonite (TiO2-MMT) complex was prepared by blending TiO2 sol and MMT with certain ratio, and its properties as an enzyme immobilization support were investigated. The pristine MMT and TiO2-MMT calcined at 800 °C (TiO2-MMT800) were used for comparison to better understand the immobilization mechanism. The structures of the pristine MMT, TiO2-MMT, and TiO2-MMT800 were examined by HR-TEM, XRD and BET. SEM was employed to study different morphologies before and after laccase immobilization. Activity and kinetic parameters of the immobilized laccase were also determined. It was found that the TiO2 nanoparticles were successfully introduced into the MMT layer structure, and this intercalation enlarged the “d value” of two adjacent MMT layers and increased the surface area, while the calcination process led to a complete collapse of the MMT layers. SEM results showed that the clays were well coated with adsorbed enzymes. The study of laccase activity revealed that the optimum pH and temperature were pH = 3 and 60 °C, respectively. In addition, the storage stability for the immobilized laccase was satisfactory. The kinetic properties indicated that laccase immobilized on TiO2-MMT complexes had a good affinity to the substrate. It has been proved that TiO2-MMT complex is a good candidate for enzyme immobilization. PMID:23771020

  10. Thermostable α-amylase immobilization: Enhanced stability and performance for starch biocatalysis.

    PubMed

    Kumar, Gudi Satheesh; Rather, Gulam Mohmad; Gurramkonda, Chandrasekhar; Reddy, Bontha Rajasekhar

    2016-01-01

    The uses of thermostable starch hydrolytic biocatalysts are steadily increasing for the industrial application because of their obvious need for biocatalytic performance at elevated temperatures. The starch liquefaction and saccharification can be carried out simultaneously by the use of thermostable starch hydrolytic biocatalysts, thus minimizing the unit operations, time, and efforts. The cost factor hampers the industrialization of expensive soluble (free) enzymes for biocatalytic applications and the immobilization of enzymes offers promising alternative to the hurdle. The present investigation was aimed for immobilization of thermostable α-amylase using calcium alginate, and statistical optimization studies were carried out for enhanced biocatalytic performance. Initially, one-parameter at a time optimization studies were carried out for identification of significant factors influencing the immobilization. Furthermore, a statistical approach, response surface methodology, was applied for immobilization of α-amylase. The immobilized α-amylase in alginate microbeads showed enhanced stability to temperature and reusable property for up to seven cycles (with the retention of 50% initial activity). Finally, the kinetic behavior of free and immobilized enzyme showed the Km value of 1.2% and 2.6% (w/v) and Vmax of 1,020 and 1,030 U, respectively. Fifty percent reduction in affinity of the immobilized enzyme toward substrate was compensated by its longer stability. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  11. Antimicrobial Properties of Lysosomal Enzymes Immobilized on NH₂Functionalized Silica-Encapsulated Magnetite Nanoparticles.

    PubMed

    Bang, Seung Hyuck; Sekhon, Simranjeet Singh; Cho, Sung-Jin; Kim, So Jeong; Le, Thai-Hoang; Kim, Pil; Ahn, Ji-Young; Kim, Yang-Hoon; Min, Jiho

    2016-01-01

    The immobilization efficiency, antimicrobial activity and recovery of lysosomal enzymes on NH2 functionalized magnetite nanoparticles have been studied under various conditions. The immobi- lization efficiency depends upon the ratio of the amount of enzyme and magnetite and it shows an increase with magnetite concentration which is due to the presence of amine group at the magnetite surface that leads to a strong attraction. The optimized reaction time to immobilize the lysosomal enzymes on magnetite was determined by using a rolling method. The immobilization efficiency increases with reaction time and reached a plateau after 5 minutes and then remained constant for 10 minutes. However, after 30 minutes the immobilization efficiency decreased to 85%, which is due to the weaker electrostatic interactions between magnetite and detached lysosomal enzymes. The recovery and stability of immobilized lysosomal enzymes has also been studied. The antimicrobial activity was almost 100% but it decreased upon reuse and no activity was observed after its reuse for seven times. The storage stability of lysosomal enzymes as an antimicrobial agent was about 88%, which decreased to 53% after one day and all activity of immobilized lysosomal enzymes was maintained after five days. Thus, the lysosomal enzymes immobilized on magnetite nanoparticles could potentially be used as antimicrobial agents to remove bacteria.

  12. Enzymatic removal of flatulence-inducing sugars in chickpea milk using free and polyvinyl alcohol immobilized alpha-galactosidase from Aspergillus oryzae.

    PubMed

    Patil, Aravind Goud G; Kote, Naganagoud V; Mulimani, Veerappa

    2009-01-01

    The treatment of chickpea milk was carried out in batch, repeated batch and continuous reaction by soluble and polyvinyl alcohol (PVA) immobilized Aspergillus oryzae alpha-galactosidase for the removal of raffinose family oligosaccharides (RFOs). In the batch mode of treatment 96 and 92% of RFOs hydrolysis was observed by soluble and immobilized enzyme, respectively. In repeated batch experiments, immobilized enzyme showed 70% RFOs hydrolysis up to sixth cycle. Polyvinyl alcohol immobilized alpha-galactosidase in fluidized bed reactor showed highest reduction of 94% at a flow rate of 30 ml/h. The results obtained from the present study are very interesting for industrial use of PVA-immobilized enzyme.

  13. [Changes of physiological functions in rats induced by immobilization stress].

    PubMed

    Kuriyama, T; Oishi, K; Kakazu, H; Machida, K

    1998-01-01

    A study was conducted on the changes of physiological function in rats due to immobilization stress. Male Fischer rats (SPF) of 32 weeks of age were housed in individual cages for 4 weeks. Then all rats were immobilized by stainless wire mesh for 6 hours daily for 3 days. Blood was collected before the 1st stress, immediately after the 1st stress, immediately after the 3rd stress and the day after the 3rd stress. The results of this experiment were as follows: (1) The total leukocyte counts in the blood of the rats after the 1st trial was significantly higher than that before the 1st trial. (2) The percentage of lymphocytes in the blood after the 1st trial was significantly lower than that before the 1st trial, whereas that of neutrophils was significantly higher. (3) Correlations between phagocytic activity and superoxide production of neutrophils by histochemical NBT reduction assay showed significantly a positive correlation before the 1st trial. However, no significant correlations were observed in immediately after the 1st trial and the 3rd trial. The day after the 3rd trial, a positive correlation was observed again. These correlations showed that an unsuitable state of the neutrophil function was induced by the immobilization stress. (4) Serum biochemical profiles were affected by the immobilization stress. Also, GOT, GPT, LDH, CK and UA were increased after the 1st trial, whereas, TG, TP, ALB and ALP were decreased after the 1st trial. T-CHO was increased only immediately after the 3rd stress. These results suggest that immobilization stress affected blood cells and serum components, and then the host defense and physiological functions were damaged respectively.

  14. Immobilized Enzymes and Cells as Practical Catalysts

    NASA Astrophysics Data System (ADS)

    Klibanov, Alexander M.

    1983-02-01

    Performance of enzymes and whole cells in commercial applications can often be dramatically improved by immobilization of the biocatalysts, for instance, by their covalent attachment to or adsorption on solid supports, entrapment in polymeric gels, encapsulation, and cross-linking. The effect of immobilization on enzymatic properties and stability of biocatalysts is considered. Applications of immobilized enzymes and cells in the chemical, pharmaceutical, and food industries, in clinical and chemical analyses, and in medicine, as well as probable future trends in enzyme technology are discussed.

  15. Immobilization of urease on activated methoxypolyethyleneglycol-5000.

    PubMed

    Hamarat, S; Uslan, A H

    1996-05-01

    Urease (E.C 3.5.1.5) was covalently immobilized on activated methoxypolyethyleneglycol-5000 which is linear, uncharged, soluble in water and nonimmunogenic. mPEG is bound to the epsilon-NH2 groups of Lysin in urease. Previously different molar ratios of urease -Lys/activated-mPEG were searched for immobilization. Storage stabilities, molecular weights and the values of blocked amino groups were determined for each immobilized urease and the best conditions was found 1:3 urease-Lys/activated mPEG. Furthermore physical characterization, kinetic constants (Km, Vmax), heat and temperature stabilites were also determined.

  16. Immobilization of biomolecules on semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Joensson, U.; Malmqvist, M.; Nilsson, H.; Olofsson, G.; Roennberg, I.

    1983-09-01

    A reproducible, stable and functional introduction of reactive groups on oxide covered silicon surfaces used in chemically sensitive field effect transistors and optical methods based on light reflection is described. Biomolecules, such as antibodies, antigens and enzymes, were covalently attached to the surface modified silicon via a thiol disulfide exchange reaction. The immobilization technique eliminates the risk of crosslinking and homopolymerization, giving monolayer coverage in close contact with the surface. The technique was used for immobilized protein A and interaction of such surfaces with immunoglobulins. The result was evaluated by in situ ellipsometry, which gives the amount of immobilized and interacting material on the surfaces.

  17. Plutonium immobilization feed batching system concept report

    SciTech Connect

    Erickson, S.

    2000-07-19

    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 high level waste glass for permanent storage. Feed batching is one of the first process steps involved with first stage plutonium immobilization. It will blend plutonium oxide powder before it is combined with other materials to make pucks. This report discusses the Plutonium Immobilization feed batching process preliminary concept, batch splitting concepts, and includes a process block diagram, concept descriptions, a preliminary equipment list, and feed batching development areas.

  18. Immobilization of Lipase from Pseudomonas fluorescens on Porous Polyurea and Its Application in Kinetic Resolution of Racemic 1-Phenylethanol.

    PubMed

    Han, Hui; Zhou, Yamei; Li, Shusheng; Wang, Yinping; Kong, Xiang Zheng

    2016-10-05

    A porous polyurea (PPU) was prepared through a simple protocol by reacting toluene diisocyanate with water in binary solvent of water-acetone. Its amine group was determined through spectrophotometric absorbance based on its iminization with p-nitrobenzaldehyde amines. PPU was then used as a novel polymer support for enzyme immobilization, through activation by glutaraldehyde followed by immobilization of an enzyme, lipase from Pseudomonas fluorescens (PFL), via covalent bonding with the amine groups of lipase molecules. Influences of glutaraldehyde and enzyme concentration and pH in the process were studied. The results revealed that the activity of the immobilized PFL reached a maximum at GA concentration of 0.17 mol/L and at pH 8. Immobilization rate of 60% or higher for PFL was obtained under optimized condition with an enzyme activity of 283 U/mg. The porous structure of PPU, prior to and after GA activation and PFL immobilization, was characterized. The activity of the immobilized PFL at different temperature and pH and its stability at 40 °C as well as its reusability were tested. The immobilized enzyme was finally used as enantioselective catalyst in kinetic resolution of racemic 1-phenylethanol (1-PEOH), and its performance compared with the free PFL. The results demonstrate that the enzyme activity and stability were greatly improved for the immobilized PFL, and highly pure enantiomers from racemic 1-PEOH were effectively achieved using the immobilized PFL. Noticeable deactivation of PFL in the resolution was observed by acetaldehyde in situ formed. In addition, the immobilized PFL was readily recovered from the reaction system for reuse. A total of 73% of the initial activity was retained after 5 repeated reuse cycles. This work provides a novel route to preparation of a polyurea porous material and its enzyme immobilization, leading to a novel type of immobilized enzyme for efficient kinetic resolution of racemic molecules.

  19. Development of a microfluidic “click chip” incorporating an immobilized Cu(I) catalyst

    PubMed Central

    Li, Hairong; Whittenberg, Joseph J.; Zhou, Haiying; Ranganathan, David; Desai, Amit V.; Koziol, Jan; Zeng, Dexing; Kenis, Paul J. A.; Reichert, David E.

    2015-01-01

    We have developed a microfluidic “click chip” incorporating an immobilized Cu(I) catalyst for click reactions. The microfluidic device was fabricated from polydimethylsiloxane (PDMS) bonded to glass and featured ~14,400 posts on the surface to improve catalyst immobilization. This design increased the immobilization efficiency and reduces the reagents’ diffusion time to active catalyst site. The device also incorporates five reservoirs to increase the reaction volume with minimal hydrodynamic pressure drop across the device. A novel water-soluble tris-(benzyltriazolylmethyl)amine (TBTA) derivative capable of stabilizing Cu(I), ligand 2, was synthesized and successfully immobilized on the chip surface. The catalyst immobilized chip surface was characterized by X-ray photoelectron spectroscopy (XPS). The immobilization efficiency was evaluated via radiotracer methods: the immobilized Cu(I) was measured as 1136±272 nmol and the surface immobilized Cu(I) density was 81±20 nmol cm−2. The active Cu(I)-ligand 2 could be regenerated up to five times without losing any catalyst efficiency. The “click” reaction of Flu568-azide and propargylamine was studied on chip for proof-of-principle. The on-chip reaction yields were ca. 82% with a 50 min reaction time or ca. 55% with a 15 min period at 37 °C, which was higher than those obtained in the conventional reaction. The on-chip “click” reaction involving a biomolecule, cyclo(RGDfK) peptide was also studied and demonstrated a conversion yield of ca. 98%. These encouraging results show promise on the application of the Cu(I) catalyst immobilized “click chip” for the development of biomolecule based imaging agents. PMID:25598970

  20. Application of Klebsiella oxytoca immobilized cells on the treatment of cyanide wastewater.

    PubMed

    Chen, C Y; Kao, C M; Chen, S C

    2008-03-01

    Klebsiella oxytoca, isolated from cyanide-containing industrial wastewater, has been shown to be able to biodegrade cyanide to non-toxic end products. The technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide was used as the target compound and both alginate and cellulose triacetate techniques were applied for the preparation of immobilized cells. Results from this study show that KCN can be utilized as the sole nitrogen source by K. oxytoca. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration and pH. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH. In the batch experiments, the maximum KCN removal efficiencies using alginate and cellulose triacetate immobilized beads were 0.108 and 0.101mM h(-1) at pH 7, respectively. Results also indicate that immobilized system can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. The maximum KCN removal rates using alginate and cellulose triacetate immobilized beads in continuous-column system were 0.224 and 0.192mMh(-1) with initial KCN concentration of 3mM, respectively. Results indicate that the immobilized cells of K. oxytoca would be applicable to the treatment of cyanide-containing wastewaters.

  1. Development of a microfluidic "click chip" incorporating an immobilized Cu(I) catalyst.

    PubMed

    Li, Hairong; Whittenberg, Joseph J; Zhou, Haiying; Ranganathan, David; Desai, Amit V; Koziol, Jan; Zeng, Dexing; Kenis, Paul J A; Reichert, David E

    2015-01-01

    We have developed a microfluidic "click chip" incorporating an immobilized Cu(I) catalyst for click reactions. The microfluidic device was fabricated from polydimethylsiloxane (PDMS) bonded to glass and featured ~14,400 posts on the surface to improve catalyst immobilization. This design increased the immobilization efficiency and reduces the reagents' diffusion time to active catalyst site. The device also incorporates five reservoirs to increase the reaction volume with minimal hydrodynamic pressure drop across the device. A novel water-soluble tris-(benzyltriazolylmethyl)amine (TBTA) derivative capable of stabilizing Cu(I), ligand 2, was synthesized and successfully immobilized on the chip surface. The catalyst immobilized chip surface was characterized by X-ray photoelectron spectroscopy (XPS). The immobilization efficiency was evaluated via radiotracer methods: the immobilized Cu(I) was measured as 1136±272 nmol and the surface immobilized Cu(I) density was 81±20 nmol cm(-2). The active Cu(I)-ligand 2 could be regenerated up to five times without losing any catalyst efficiency. The "click" reaction of Flu568-azide and propargylamine was studied on chip for proof-of-principle. The on-chip reaction yields were ca. 82% with a 50 min reaction time or ca. 55% with a 15 min period at 37 °C, which was higher than those obtained in the conventional reaction. The on-chip "click" reaction involving a biomolecule, cyclo(RGDfK) peptide was also studied and demonstrated a conversion yield of ca. 98%. These encouraging results show promise on the application of the Cu(I) catalyst immobilized "click chip" for the development of biomolecule based imaging agents.

  2. Application of Denatured, Electrophoretically Separated, and Immobilized Lysates of Herpes Simplex Virus-Infected Cells for Detection of Monoclonal Antibodies and for Studies of the Properties of Viral Proteins

    PubMed Central

    Braun, Daniel K.; Pereira, Lenore; Norrild, Bodil; Roizman, Bernard

    1983-01-01

    We report the use of herpes simplex virus type 1 (HSV-1)- and HSV-2-infected cell polypeptides (ICPs) separated by electrophoresis in polyacrylamide gels and transferred to nitrocellulose to (i) detect monoclonal antibodies to viral polypeptides and to (ii) study the properties of the proteins with the monoclonal antibodies. Our results were as follows. (i) When the antigens were electrophoretically separated in denaturing gels and then immobilized on nitrocellulose strips, we detected a greater diversity of monoclonal antibodies to viral proteins than when we used the technique of immune precipitation of soluble, nondenatured viral antigens. The primary advantage of the technique is in the detection of nonprecipitating antibody and of antibody to poorly soluble antigens not available for reaction in preparations cleared by high-speed centrifugation before immune reaction. (ii) Studies of the viral polypeptides reactive with three monoclonal antibodies indicated that the technique can be used to investigate several properties of the antigens. Specifically, monoclonal antibody to ICP 4 confirmed the accumulation of viral protein in the nucleus and the mapping of the gene in the S component. The results showed, however, that HSV-1 and HSV-2 ICP 4 do have common antigenic determinants. The reaction of a nonprecipitating monoclonal antibody with electrophoretically separated, immobilized polypeptides contained in cytoplasmic and nuclear fractions, those chemically deglycosylated, or those specified by specific HSV-1 x HSV-2 intertypic recombinants identified the antigens reactive with the second monoclonal antibody as various forms of glycoprotein gC. Of particular interest was a set of four antigens, 39,000 to 46,500 in apparent molecular weight, reactive with each of several monoclonal antibodies. These studies showed that two polypeptides partition in the cytoplasm and two in the nucleus and that all comap with the previously mapped ICPs 35 and 37 in the region of

  3. Covalent-bonded immobilization of lipase on poly(phenylene sulfide) dendrimers and their hydrolysis ability.

    PubMed

    Yemul, Omprakash; Imae, Toyoko

    2005-01-01

    Covalent-bonded immobilization of lipase from burkholderia cepacia onto two poly(phenylene sulfide) (PPS) dendrimers with different generations (two and three) was achieved using carbodiimide as a coupling reagent. The hydrolysis activity of olive oil to fatty acid was studied on enzyme-immobilized PPS dendrimers. Enzyme activity was proportional to the enzyme loading, and highest recovered activity was obtained at the medium enzyme loading for both G2 and G3 dendrimers. The immobilization improved the optimum pH and caused the temperature range to widen. Immobilization of enzyme has enhanced the thermal stability of enzyme activity in comparison with free enzyme. The immobilized enzyme as a biocatalyst for batch hydrolysis of olive oil retained 80 approximately 90% activity even after 20 times of recycling. This retention of activity after recycle is very valuable and powerful in enzyme technology. The present noteworthy and vital availability on enzyme reaction of the covalently bonded immobilized lipase on dendrimer came from the structure of dendrimer with a large number of functional terminal groups, which are easily available for immobilization of many lipases at the situation keeping reactive enzymes on the surface of dendrimer.

  4. Immobilization of modified papain with anhydride groups on activated cotton fabric.

    PubMed

    Xue, Yong; Nie, Huali; Zhu, Limin; Li, Shubai; Zhang, Haitao

    2010-01-01

    Papain (EC 3.4.22.2) has been chemically modified using two novel reagents including different anhydrides of 1,2,4-benzenetricarboxylic and pyromellitic acids. Then, the modified papain was immobilized on the activated cotton fabric by a two-step method. The number of free amino groups in the modified protein was investigated through the 2,4,6-trinitrobenzenesulfonic acid method. Energy dispersive spectrometer was used to characterize papain immobilization. Some parameters of both modified and native papain immobilized on cotton fabric, such as optimum temperature, optimum pH, and the stabilities for reservation in various detergents were studied and compared. The resultant papain had its optimum pH shifted from 6.0 to 9.0. Compared with immobilized native papain, the thermal stability and the resistance to alkali and washing detergent of immobilized modified enzyme were improved considerably. When the concentration of detergent was 20 mg/ml, the activity of the