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Sample records for prevent protein adsorption

  1. Preventing protein adsorption from a range of surfaces using an aqueous fish protein extract

    DEFF Research Database (Denmark)

    Pillai, Saju; Arpanaei, Ayyoob; Meyer, Rikke L.

    2009-01-01

    We utilize an aqueous extract of fish proteins (FPs) as a coating for minimizing the adsorption of fibrinogen (Fg) and human serum albumin (HSA). The surfaces include stainless steel (SS), gold (Au), silicon dioxide (SiO2), and poly(styrene) (PS). The adsorption processes (kinetics and adsorbed...

  2. Applications of functional polymer brushes for nanoparticle uptake and prevention of protein adsorption

    Science.gov (United States)

    Arifuzzaman, Shafi M.

    The central theme of this Ph.D. dissertation is to develop novel multifunctional polymer coatings for understanding partition of proteins and nanoparticles on polymers grafted to flat surfaces (so-called brushes). Systematic investigation of the adsorption phenomena is accomplished by utilizing surface-anchored assemblies comprising grafted polymers with variation in physical properties (i.e., length or/and grafting density) and chemical functionality. The chemical composition of the brush is tailored by either "chemical coloring" of a parent homopolymer brush with selective chemical moieties or by sequential growth of two chemically dissimilar polymer blocks. We present preparation of two types of tailor-made, surface-grafted copolymers: (1) those composed of hydrophilic and hydrophobic blocks (so-called amphiphilic polymer brushes), and (2) those comprising of anionic and cationic polymer segments (so-called polyampholyte brushes). We describe the organization of functionality in the grafted polymer brushes and the partitioning of proteins and nanoparticles using a battery of complementary analytical probes. Specifically, we address how varying the molecular weight, grafting density, and chemical composition of the brush affects adsorbtion and desorbtion of model proteins and gold nanoparticles. Our observations indicate densely-populated responsive amphiphilic polymers are very efficient in suppressing protein adsorption. In addition, we have established that the length of poly(ethylene glycol) spacers attached to a parent homopolymer brush is a key factor governing uptake of gold nanoparticles. Both grafting density and molecular weight of the coating are important in controlling the kinetics and thermodynamics of protein adsorption on surfaces. Our findings and methodologies can lead to the development of next generation environmentally friendly antifouling surfaces and will find application in medical devices, antifouling coatings and anti reflection finishes.

  3. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces...... is monitored simultaneously and the influence from the presence of other human serum proteins on albumin and IgG adsorption, as well as their mutual influence during adsorption processes, is investigated. Exploring protein adsorption by combining analysis of competitive adsorption from complex solutions...... of high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces...

  4. Modification of nanoelectrode ensembles by thiols and disulfides to prevent non specific adsorption of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Silvestrini, M. [Department of Molecular Sciences and Nanosystems, University Ca' Foscari of Venice, Santa Marta 2137, 30123 Venice (Italy); Schiavuta, P.; Scopece, P. [Associazione CIVEN, via delle Industrie 5, 30175 Marghera - Venice (Italy); Pecchielan, G.; Moretto, L.M. [Department of Molecular Sciences and Nanosystems, University Ca' Foscari of Venice, Santa Marta 2137, 30123 Venice (Italy); Ugo, P., E-mail: ugo@unive.it [Department of Molecular Sciences and Nanosystems, University Ca' Foscari of Venice, Santa Marta 2137, 30123 Venice (Italy)

    2011-09-01

    Highlights: > Complex nanostructures are built on the gold surface of ensembles of nanoelectrodes. > Gold surface of nanoelectrodes was functionalized with SAM of organic sulphurs. > The polycarbonate surrounding nanoelectrodes was functionalized with proteins. > SAMs protect the nanoelectrodes from undesired proteins adsorption. - Abstract: The possibility to functionalize selectively with thiols or disulfides the surface of the gold nanoelectrodes of polycarbonate templated nanoelectrode ensembles (NEEs) is studied. It is shown that the Au nanoelectrodes can be coated by a self assembled monolayer (SAM) of thioctic acid (TA) or 2-mercaptoethanesulfonic (MES) acid. The study of the electrochemical behavior of SAM-modified NEEs by cyclic voltammetry (CV) at different solution pH, using ferrocenecarboxylate as an anionic redox probe (FcCOO{sup -}) and (ferrocenylmethyl)trimethylammonium (FA{sup +}) as a cationic redox probe, demonstrate that the SAM-modified nanoelectrodes are permselective, in that only cationic or neutral probes can access the SAM-coated nanoelectrode surface. CV, AFM and FTIR-ATR data indicate that proteins such as casein or bovine serum albumin, which are polyanionic at pH 7, adsorb on the surface of NEEs untreated with thiols, tending to block the electron transfer of the ferrocenyl redox probes. On the contrary, the pre-treatment of the NEE with an anionic SAM protects the nanoelectrodes from protein fouling, allowing the detection of well shaped voltammetric patterns for the redox probe. Experimental results indicate that, in the case of MES treated NEEs, the protein is bound only onto the polycarbonate surface which surrounds the nanoelectrodes, while the tips of the gold nanoelectrodes remain protein free.

  5. Modification of nanoelectrode ensembles by thiols and disulfides to prevent non specific adsorption of proteins

    International Nuclear Information System (INIS)

    Silvestrini, M.; Schiavuta, P.; Scopece, P.; Pecchielan, G.; Moretto, L.M.; Ugo, P.

    2011-01-01

    Highlights: → Complex nanostructures are built on the gold surface of ensembles of nanoelectrodes. → Gold surface of nanoelectrodes was functionalized with SAM of organic sulphurs. → The polycarbonate surrounding nanoelectrodes was functionalized with proteins. → SAMs protect the nanoelectrodes from undesired proteins adsorption. - Abstract: The possibility to functionalize selectively with thiols or disulfides the surface of the gold nanoelectrodes of polycarbonate templated nanoelectrode ensembles (NEEs) is studied. It is shown that the Au nanoelectrodes can be coated by a self assembled monolayer (SAM) of thioctic acid (TA) or 2-mercaptoethanesulfonic (MES) acid. The study of the electrochemical behavior of SAM-modified NEEs by cyclic voltammetry (CV) at different solution pH, using ferrocenecarboxylate as an anionic redox probe (FcCOO - ) and (ferrocenylmethyl)trimethylammonium (FA + ) as a cationic redox probe, demonstrate that the SAM-modified nanoelectrodes are permselective, in that only cationic or neutral probes can access the SAM-coated nanoelectrode surface. CV, AFM and FTIR-ATR data indicate that proteins such as casein or bovine serum albumin, which are polyanionic at pH 7, adsorb on the surface of NEEs untreated with thiols, tending to block the electron transfer of the ferrocenyl redox probes. On the contrary, the pre-treatment of the NEE with an anionic SAM protects the nanoelectrodes from protein fouling, allowing the detection of well shaped voltammetric patterns for the redox probe. Experimental results indicate that, in the case of MES treated NEEs, the protein is bound only onto the polycarbonate surface which surrounds the nanoelectrodes, while the tips of the gold nanoelectrodes remain protein free.

  6. Protein Adsorption in Three Dimensions

    Science.gov (United States)

    Vogler, Erwin A.

    2011-01-01

    Recent experimental and theoretical work clarifying the physical chemistry of blood-protein adsorption from aqueous-buffer solution to various kinds of surfaces is reviewed and interpreted within the context of biomaterial applications, especially toward development of cardiovascular biomaterials. The importance of this subject in biomaterials surface science is emphasized by reducing the “protein-adsorption problem” to three core questions that require quantitative answer. An overview of the protein-adsorption literature identifies some of the sources of inconsistency among many investigators participating in more than five decades of focused research. A tutorial on the fundamental biophysical chemistry of protein adsorption sets the stage for a detailed discussion of the kinetics and thermodynamics of protein adsorption, including adsorption competition between two proteins for the same adsorbent immersed in a binary-protein mixture. Both kinetics and steady-state adsorption can be rationalized using a single interpretive paradigm asserting that protein molecules partition from solution into a three-dimensional (3D) interphase separating bulk solution from the physical-adsorbent surface. Adsorbed protein collects in one-or-more adsorbed layers, depending on protein size, solution concentration, and adsorbent surface energy (water wettability). The adsorption process begins with the hydration of an adsorbent surface brought into contact with an aqueous-protein solution. Surface hydration reactions instantaneously form a thin, pseudo-2D interface between the adsorbent and protein solution. Protein molecules rapidly diffuse into this newly-formed interface, creating a truly 3D interphase that inflates with arriving proteins and fills to capacity within milliseconds at mg/mL bulk-solution concentrations CB. This inflated interphase subsequently undergoes time-dependent (minutes-to-hours) decrease in volume VI by expulsion of either-or-both interphase water and

  7. Adsorption behavior of protein onto siloxane microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bailing [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China)]. E-mail: Blliuchem@hotmail.com; Cao Shunsheng [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Deng Xiaobo [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Li Songjun [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Luo Rong [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China)

    2006-09-15

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption.

  8. Adsorption behavior of protein onto siloxane microspheres

    International Nuclear Information System (INIS)

    Liu Bailing; Cao Shunsheng; Deng Xiaobo; Li Songjun; Luo Rong

    2006-01-01

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption

  9. Molecular printboards as a general platform for protein immobilization: A supramolecular solution to nonspecific adsorption

    NARCIS (Netherlands)

    Ludden, M.J.W.; Mulder, A.; Tampe, Robert; Reinhoudt, David; Huskens, Jurriaan

    2007-01-01

    Be specific: A supramolecular adsorbate consisting of an adamantyl group (red) and an oligo(ethylene glycol) chain has been designed to prevent nonspecific protein adsorption at cyclodextrin molecular printboards. The adamantyl group allows specific and reversible interactions. Specific

  10. Reusable hydroxyapatite nanocrystal sensors for protein adsorption

    International Nuclear Information System (INIS)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Hanagata, Nobutaka; Chakarov, Dinko; Kasemo, Bengt; Tanaka, Junzo

    2010-01-01

    The repeatability of the adsorption and removal of fibrinogen and fetal bovine serum on hydroxyapatite (HAp) nanocrystal sensors was investigated by Fourier transform infrared (FTIR) spectroscopy and quartz crystal microbalance with dissipation (QCM-D) monitoring technique. The HAp nanocrystals were coated on a gold-coated quartz sensor by electrophoretic deposition. Proteins adsorbed on the HAp sensors were removed by (i) ammonia/hydrogen peroxide mixture (APM), (ii) ultraviolet light (UV), (iii) UV/APM, (iv) APM/UV and (v) sodium dodecyl sulfate (SDS) treatments. FTIR spectra of the reused surfaces revealed that the APM and SDS treatments left peptide fragments or the proteins adsorbed on the surfaces, whereas the other methods successfully removed the proteins. The QCM-D measurements indicated that in the removal treatments, fibrinogen was slowly adsorbed in the first cycle because of the change in surface wettability revealed by contact angle measurements. The SDS treatment was not effective in removing proteins. The APM or UV treatment decreased the frequency shifts for the reused HAp sensors. The UV/APM treatment did not induce the frequency shifts but decreased the dissipation shifts. Therefore, we conclude that the APM/UV treatment is the most useful method for reproducing protein adsorption behavior on HAp sensors.

  11. Reusable hydroxyapatite nanocrystal sensors for protein adsorption

    Directory of Open Access Journals (Sweden)

    Motohiro Tagaya, Toshiyuki Ikoma, Nobutaka Hanagata, Dinko Chakarov, Bengt Kasemo and Junzo Tanaka

    2010-01-01

    Full Text Available The repeatability of the adsorption and removal of fibrinogen and fetal bovine serum on hydroxyapatite (HAp nanocrystal sensors was investigated by Fourier transform infrared (FTIR spectroscopy and quartz crystal microbalance with dissipation (QCM-D monitoring technique. The HAp nanocrystals were coated on a gold-coated quartz sensor by electrophoretic deposition. Proteins adsorbed on the HAp sensors were removed by (i ammonia/hydrogen peroxide mixture (APM, (ii ultraviolet light (UV, (iii UV/APM, (iv APM/UV and (v sodium dodecyl sulfate (SDS treatments. FTIR spectra of the reused surfaces revealed that the APM and SDS treatments left peptide fragments or the proteins adsorbed on the surfaces, whereas the other methods successfully removed the proteins. The QCM-D measurements indicated that in the removal treatments, fibrinogen was slowly adsorbed in the first cycle because of the change in surface wettability revealed by contact angle measurements. The SDS treatment was not effective in removing proteins. The APM or UV treatment decreased the frequency shifts for the reused HAp sensors. The UV/APM treatment did not induce the frequency shifts but decreased the dissipation shifts. Therefore, we conclude that the APM/UV treatment is the most useful method for reproducing protein adsorption behavior on HAp sensors.

  12. Statistical inference in single molecule measurements of protein adsorption

    Science.gov (United States)

    Armstrong, Megan J.; Tsitkov, Stanislav; Hess, Henry

    2018-02-01

    Significant effort has been invested into understanding the dynamics of protein adsorption on surfaces, in particular to predict protein behavior at the specialized surfaces of biomedical technologies like hydrogels, nanoparticles, and biosensors. Recently, the application of fluorescent single molecule imaging to this field has permitted the tracking of individual proteins and their stochastic contribution to the aggregate dynamics of adsorption. However, the interpretation of these results is complicated by (1) the finite time available to observe effectively infinite adsorption timescales and (2) the contribution of photobleaching kinetics to adsorption kinetics. Here, we perform a protein adsorption simulation to introduce specific survival analysis methods that overcome the first complication. Additionally, we collect single molecule residence time data from the adsorption of fibrinogen to glass and use survival analysis to distinguish photobleaching kinetics from protein adsorption kinetics.

  13. A review of the thermodynamics of protein association to ligands, protein adsorption, and adsorption isotherms

    DEFF Research Database (Denmark)

    Mollerup, Jørgen

    2008-01-01

    The application of thermodynamic models in the development of chromatographic separation processes is discussed. The paper analyses the thermodynamic principles of protein adsorption. It can be modeled either as a reversible association between the adsorbate and the ligands or as a steady...

  14. Prevention of adsorption losses during radioimmunoassay of polypeptide hormones: effectiveness of albumins, gelatin, caseins, Tween 20 and plasma

    International Nuclear Information System (INIS)

    Livesey, J.H.; Donald, R.A.

    1982-01-01

    It is well known that polypeptide hormones adsorb to glass and plastic surfaces and that this adsorption may be reduced by adding a relatively large quantity of another protein. Consequently proteins (or sometimes detergents) are added almost universally to peptide hormone radioimmunassays to minimise loss of analyte by adsorption. This study was undertaken because there are few reports of the relative effectiveness of the proteins so used. The results suggest that moderate concentrations of the widely used albumins of Tween 20 do not always adequately prevent the adsorption of hormonal polypeptides to surfaces. Casein and alkali-treated casein appear to be more effective than the adsorption inhibitors in general use in radioimmunoassay for the range of hormones and adsorptive surfaces tested. They were also found to be very effective for preventing the adsorption of radio-labelled human luteinizing hormone, human growth hormone and Tyr-somatostatin. (Auth.)

  15. Competitive protein adsorption to polymer surface from human serum

    DEFF Research Database (Denmark)

    Holmberg, Maria; Jensen, Karin Bagger Stibius; Larsen, Niels Bent

    2008-01-01

    Surface modification by "soft" plasma polymerisation to obtain a hydrophilic and non-fouling polymer surface has been validated using radioactive labelling. Adsorption to unmodified and modified polymer surfaces, from both single protein and human serum solutions, has been investigated. By using...... different radioisotopes, albumin and Immunoglobulin G (IgG) adsorption has been monitored simultaneously during competitive adsorption processes, which to our knowledge has not been reported in the literature before. Results show that albumin and IgG adsorption is dependent on adsorption time...... and on the presence and concentration of other proteins in bulk solutions during adsorption. Generally, lower albumin and IgG adsorption was observed on the modified and more hydrophilic polymer surfaces, but otherwise the modified and unmodified polymer surfaces showed the same adsorption characteristics....

  16. Magnetic polymeric microspheres for protein adsorption

    International Nuclear Information System (INIS)

    Felinto, M.C.F.C.; Parra, D.F.; Lugao, A.B.; Batista, M.P.; Higa, O.Z.; Yamaura, M.; Camilo, R.L.; Ribela, M.T.C.P.; Sampaio, L.C.

    2005-01-01

    Magnetic beads consisting of polymer-coated manganese ferrite nanoparticles were prepared by the precipitation reaction of manganese ferrite into the channels of methyl methacrylate polymer beads by sodium hydroxide, resulting in MnMagBead. MnMagBead was characterized by infrared spectra (FTIR), thermogravimetric analysis of TGA/DTG and indicates the presence of -CO (carbonyl) groups and the MnFe 2 O 4 on the beads. Magnetization measurements were obtained at room temperature in magnetic fields up to 10 KOe using a vibrating sample magnetometer. Introductory Protein adsorption biological tests were processed using labeled I-125 albumin (BSA), and the activity was measured in a gamma counting spectrometer. These superparamagnetic beads exhibit the capacity to bind biological molecules such as proteins like albumin, with a good capability (5 x 10 -6 ) μg/100 mg of beads as compared with other magnetic resins studied in our group

  17. Competitive Protein Adsorption on Polysaccharide and Hyaluronate Modified Surfaces

    Science.gov (United States)

    Ombelli, Michela; Costello, Lauren; Postle, Corinne; Anantharaman, Vinod; Meng, Qing Cheng; Composto, Russell J.; Eckmann, David M.

    2011-01-01

    We measured adsorption of bovine serum albumin (BSA) and fibrinogen (Fg) onto six distinct bare and dextran- and hyaluronate-modified silicon surfaces created using two dextran grafting densities and three hyaluronic acid (HA) sodium salts derived from human umbilical cord, rooster comb and streptococcus zooepidemicus. Film thickness and surface morphology depended on HA molecular weight and concentration. BSA coverage was enhanced on surfaces upon competitive adsorption of BSA:Fg mixtures. Dextranization differentially reduced protein adsorption onto surfaces based on oxidation state. Hyaluronization was demonstrated to provide the greatest resistance to protein coverage, equivalent to that of the most resistant dextranized surface. Resistance to protein adsorption was independent of the type of hyaluronic acid utilized. With changing bulk protein concentration from 20 to 40 µg ml−1 for each species, Fg coverage on silicon increased by 4×, whereas both BSA and Fg adsorption on dextran and HA were far less dependent of protein bulk concentration. PMID:21623481

  18. Competitive Protein Adsorption of Albumin and Immunoglobulin G from Human Serum onto Polymer Surfaces

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2010-01-01

    protein adsorption from diluted human serum solutions with relatively low protein concentrations, but the nonfouling character was weakened when less diluted human serum solutions with higher protein concentrations were used. The observed adsorption trend is independent of adsorption time, indicating...

  19. Protein adsorption on nanoparticles: model development using computer simulation

    International Nuclear Information System (INIS)

    Shao, Qing; Hall, Carol K

    2016-01-01

    The adsorption of proteins on nanoparticles results in the formation of the protein corona, the composition of which determines how nanoparticles influence their biological surroundings. We seek to better understand corona formation by developing models that describe protein adsorption on nanoparticles using computer simulation results as data. Using a coarse-grained protein model, discontinuous molecular dynamics simulations are conducted to investigate the adsorption of two small proteins (Trp-cage and WW domain) on a model nanoparticle of diameter 10.0 nm at protein concentrations ranging from 0.5 to 5 mM. The resulting adsorption isotherms are well described by the Langmuir, Freundlich, Temkin and Kiselev models, but not by the Elovich, Fowler–Guggenheim and Hill–de Boer models. We also try to develop a generalized model that can describe protein adsorption equilibrium on nanoparticles of different diameters in terms of dimensionless size parameters. The simulation results for three proteins (Trp-cage, WW domain, and GB3) on four nanoparticles (diameter  =  5.0, 10.0, 15.0, and 20.0 nm) illustrate both the promise and the challenge associated with developing generalized models of protein adsorption on nanoparticles. (paper)

  20. Contributions of depth filter components to protein adsorption in bioprocessing.

    Science.gov (United States)

    Khanal, Ohnmar; Singh, Nripen; Traylor, Steven J; Xu, Xuankuo; Ghose, Sanchayita; Li, Zheng J; Lenhoff, Abraham M

    2018-04-16

    Depth filtration is widely used in downstream bioprocessing to remove particulate contaminants via depth straining and is therefore applied to harvest clarification and other processing steps. However, depth filtration also removes proteins via adsorption, which can contribute variously to impurity clearance and to reduction in product yield. The adsorption may occur on the different components of the depth filter, that is, filter aid, binder, and cellulose filter. We measured adsorption of several model proteins and therapeutic proteins onto filter aids, cellulose, and commercial depth filters at pH 5-8 and ionic strengths filter component in the adsorption of proteins with different net charges, using confocal microscopy. Our findings show that a complete depth filter's maximum adsorptive capacity for proteins can be estimated by its protein monolayer coverage values, which are of order mg/m 2 , depending on the protein size. Furthermore, the extent of adsorption of different proteins appears to depend on the nature of the resin binder and its extent of coating over the depth filter surface, particularly in masking the cation-exchanger-like capacity of the siliceous filter aids. In addition to guiding improved depth filter selection, the findings can be leveraged in inspiring a more intentional selection of components and design of depth filter construction for particular impurity removal targets. © 2018 Wiley Periodicals, Inc.

  1. Structural determinants for protein adsorption/non-adsorption to silica surface

    International Nuclear Information System (INIS)

    Mathe, Christelle; Devineau, Stephanie; Aude, Jean-Christophe; Lagniel, Gilles; Chedin, Stephane; Legros, Veronique; Mathon, Marie-Helene; Renault, Jean-Philippe; Pin, Serge; Boulard, Yves; Labarre, Jean

    2013-01-01

    The understanding of the mechanisms involved in the interaction of proteins with inorganic surfaces is of major interest in both fundamental research and applications such as nano-technology. However, despite intense research, the mechanisms and the structural determinants of protein/surface interactions are still unclear. We developed a strategy consisting in identifying, in a mixture of hundreds of soluble proteins, those proteins that are adsorbed on the surface and those that are not. If the two protein subsets are large enough, their statistical comparative analysis must reveal the physicochemical determinants relevant for adsorption versus non-adsorption. This methodology was tested with silica nanoparticles. We found that the adsorbed proteins contain a higher number of charged amino acids, particularly arginine, which is consistent with involvement of this basic amino acid in electrostatic interactions with silica. The analysis also identified a marked bias toward low aromatic amino acid content (phenylalanine, tryptophan, tyrosine and histidine) in adsorbed proteins. Structural analyses and molecular dynamics simulations of proteins from the two groups indicate that non-adsorbed proteins have twice as many p-p interactions and higher structural rigidity. The data are consistent with the notion that adsorption is correlated with the flexibility of the protein and with its ability to spread on the surface. Our findings led us to propose a refined model of protein adsorption. (authors)

  2. Structural determinants for protein adsorption/non-adsorption to silica surface.

    Directory of Open Access Journals (Sweden)

    Christelle Mathé

    Full Text Available The understanding of the mechanisms involved in the interaction of proteins with inorganic surfaces is of major interest in both fundamental research and applications such as nanotechnology. However, despite intense research, the mechanisms and the structural determinants of protein/surface interactions are still unclear. We developed a strategy consisting in identifying, in a mixture of hundreds of soluble proteins, those proteins that are adsorbed on the surface and those that are not. If the two protein subsets are large enough, their statistical comparative analysis must reveal the physicochemical determinants relevant for adsorption versus non-adsorption. This methodology was tested with silica nanoparticles. We found that the adsorbed proteins contain a higher number of charged amino acids, particularly arginine, which is consistent with involvement of this basic amino acid in electrostatic interactions with silica. The analysis also identified a marked bias toward low aromatic amino acid content (phenylalanine, tryptophan, tyrosine and histidine in adsorbed proteins. Structural analyses and molecular dynamics simulations of proteins from the two groups indicate that non-adsorbed proteins have twice as many π-π interactions and higher structural rigidity. The data are consistent with the notion that adsorption is correlated with the flexibility of the protein and with its ability to spread on the surface. Our findings led us to propose a refined model of protein adsorption.

  3. Enhancing protein adsorption simulations by using accelerated molecular dynamics.

    Directory of Open Access Journals (Sweden)

    Christian Mücksch

    Full Text Available The atomistic modeling of protein adsorption on surfaces is hampered by the different time scales of the simulation ([Formula: see text][Formula: see text]s and experiment (up to hours, and the accordingly different 'final' adsorption conformations. We provide evidence that the method of accelerated molecular dynamics is an efficient tool to obtain equilibrated adsorption states. As a model system we study the adsorption of the protein BMP-2 on graphite in an explicit salt water environment. We demonstrate that due to the considerably improved sampling of conformational space, accelerated molecular dynamics allows to observe the complete unfolding and spreading of the protein on the hydrophobic graphite surface. This result is in agreement with the general finding of protein denaturation upon contact with hydrophobic surfaces.

  4. Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

    International Nuclear Information System (INIS)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Yoshioka, Tomohiko; Tanaka, Junzo; Takemura, Taro; Hanagata, Nobutaka

    2011-01-01

    Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift (Δf) and dissipation energy shift (ΔD), and the viscoelastic change as ΔD-Δf plot. The Col adsorption showed larger Δf and ΔD values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The ΔD-Δf plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

  5. Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Yoshioka, Tomohiko; Tanaka, Junzo [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo, Tokyo 152-8550 (Japan); Takemura, Taro; Hanagata, Nobutaka, E-mail: tagaya.m.aa@m.titech.ac.jp [Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-10-29

    Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift ({Delta}f) and dissipation energy shift ({Delta}D), and the viscoelastic change as {Delta}D-{Delta}f plot. The Col adsorption showed larger {Delta}f and {Delta}D values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The {Delta}D-{Delta}f plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

  6. Adsorption of plasma proteins : adsorption behaviour on apolar surfaces and effect on colloid stability

    NARCIS (Netherlands)

    van der Scheer, Albert

    1978-01-01

    In this thesis the adsorption of some plasma proteins (human albumin (HSA) and fibrinogen (HFb)) on non polar surfaces is studied, together with the influence of these proteins on the stability of polystyrene latices. The aim of these investigations is a better understanding of the processes

  7. TIRF and its application to protein adsorption : electrostatics and orientation

    NARCIS (Netherlands)

    Bos, M.A.

    1994-01-01

    The aim of the study in this thesis was to develop a method for determining the orientation of adsorbed protein molecules and to study the influence of the electrical potential of the interface on the interfacial properties of proteins, including their orientation.

    In the adsorption

  8. Protein adsorption onto nanozeolite: effect of micropore openings.

    Science.gov (United States)

    Wu, Jiamin; Li, Xiang; Yan, Yueer; Hu, Yuanyuan; Zhang, Yahong; Tang, Yi

    2013-09-15

    A clear and deep understanding of protein adsorption on porous surfaces is desirable for the reasonable design and applications of porous materials. In this study, the effect of surface micropores on protein adsorption was systematically investigated by comparing adsorption behavior of cytochrome c (Cyto-c) and Candida antarctica Lipase B (CALB) on porous and non-porous nanozeolites silicalite-1 and Beta. It was found that micropore openings on the surface of nanozeolites played a key role in determining adsorption affinity, conformations, and activities of proteins. Both Cyto-c and CALB showed higher affinity to porous nanozeolites than to non-porous ones, resulting in greater conformational change of proteins on porous surfaces which in turn affected their bio-catalytic performance. The activity of Cyto-c improved while that of CALB decreased on porous nanozeolites. Recognition of certain amino acid residues or size-matching secondary structures by micropore openings on the surface of nanozeolites was proposed to be the reason. Moreover, the pore opening effect of porous nanozeolites on protein behavior could be altered by changing protein coverage on them. This study gives a novel insight into the interaction between proteins and microporous materials, which will help to guide the rational fabrication and bio-applications of porous materials in the future. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Protein aggregation and degradation during iodine labeling and its consequences for protein adsorption to biomaterials

    DEFF Research Database (Denmark)

    Holmberg, Maria; Jensen, Karin Bagger Stibius; Ndoni, Sokol

    2007-01-01

    Protein adsorption on modified and unmodified polymer surfaces investigated through radiolabeling experiments showed a tendency for higher than expected albumin and immunoglobulin G (IgG) adsorption. Possible enhanced protein aggregation and degradation caused by the iodine labeling method used w...

  10. Modulating Protein Adsorption on Oxygen Plasma Modified Polysiloxane Surfaces

    International Nuclear Information System (INIS)

    Marletta, G.

    2006-01-01

    In the present paper we report the study on the adsorption behaviour of three model globular proteins, Human Serum Albumin, Lactoferrin and Egg Chicken Lysozyme onto both unmodified surfaces of a silicon-based polymer and the corresponding plasma treated surfaces. In particular, thin films of hydrophobic polysiloxane (about 90 degree of static water contact angle, WCA) were converted by oxygen plasma treatment at reduced pressure into very hydrophilic phases of SiOx (WCA less than 5 degree). The kinetics of protein adsorption processes were investigated by QCM-D technique, while the chemical structure and topography of the protein adlayer have been studied by Angular resolved-XPS and AFM respectively. It turned out that Albumin and Lysozyme exhibited the opposite preferential adsorption respectively onto the hydrophobic and hydrophilic surfaces, while Lactoferrin did not exhibit significant differences. The observed protein behaviour are discussed both in terms of surface-dependent parameters, including surface free energy and chemical structure, and in terms of protein-dependent parameters, including charge as well as the average molecular orientation in the adlayers. Finally, some examples of differential adsorption behaviour of the investigated proteins are reported onto nanopatterned polysiloxane surfaces consisting of hydrophobic nanopores surrounded by hydrophilic (plasma-treated) matrix and the reverse

  11. Use of quasi-isoelectric buffers to limit protein adsorption in capillary zone electrophoresis.

    Science.gov (United States)

    Poitevin, Martine; Hammad, Karim; Ayed, Ichraf; Righetti, Pier Giorgio; Peltre, Gabriel; Descroix, Stephanie

    2008-08-01

    The use of quasi-isoelectric buffers consisting of narrow pH cuts of carrier ampholytes (NC) has been investigated to limit protein adsorption on capillary walls during capillary zone electrophoresis experiments. To quantify protein adsorption on the silica surface, a method derived from that of Towns and Regnier has been developed. alpha-Lactalbumin (14 kDa, pI 4.8) and alpha-chymotrypsinogen A (25 kDa, pI 9.2) have been used as model proteins. Acidic narrow pH cuts of carrier ampholytes (NC, pH 3.0) obtained from fractionation of Serva 4-9 carrier ampholytes were used as BGE in bare-silica capillaries, and allowed to decrease significantly protein adsorption, as compared to experiments performed with classical formate buffer. The use of NC as BGE appeared to be as efficient as the use of polydimethylacrylamide coating to prevent protein adsorption. This increase of protein recovery when using NC was attributed to the interaction of carrier ampholytes with the silica surface, leading to a shielding of the capillary wall.

  12. Surface charge effects in protein adsorption on nanodiamonds.

    Science.gov (United States)

    Aramesh, M; Shimoni, O; Ostrikov, K; Prawer, S; Cervenka, J

    2015-03-19

    Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins (bovine serum albumin and lysozyme) of different properties (charge, molecular weight and rigidity), the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified. Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge-induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high (11-12) and low (1-3) respectively, which has a profound impact on the protein charge, hydration and affinity to the nanodiamonds. Small proteins (lysozyme) were found to form multilayers with significant conformational changes to screen the surface charge, while larger proteins (albumin) formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids.

  13. Study of BSA protein adsorption/release on hydroxyapatite nanoparticles

    Science.gov (United States)

    Swain, Sanjaya Kumar; Sarkar, Debasish

    2013-12-01

    Three different spherical, rod and fibrous morphologies of hydroxyapatite (HA) nanoparticles have been prepared through control over the processing parameters like temperature, pH and Ca:P ratio. Protein adsorption/release with respect to HA nanoparticle morphologies are investigated using model protein bovine serum albumin (BSA). BSA adsorption on HA nanoparticles follows Langmuir adsorption isotherm. Thermal analysis and FT-IR spectrum confirms the BSA adhesion and retention of their secondary structure. High surface area with high Ca:P ratio nanorod adsorbs relatively more amount (28 mg BSA/gm of nanorod HA) of BSA within 48 h in comparison with counterpart fibroid and spherical morphologies. Slow and steady BSA release (75 wt% of adsorbed BSA in 96 h) from nanorod HA is found as futuristic drug delivery media.

  14. Surface charge effects in protein adsorption on nanodiamonds

    Science.gov (United States)

    Aramesh, M.; Shimoni, O.; Ostrikov, K.; Prawer, S.; Cervenka, J.

    2015-03-01

    Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins (bovine serum albumin and lysozyme) of different properties (charge, molecular weight and rigidity), the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified. Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge-induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high (11-12) and low (1-3) respectively, which has a profound impact on the protein charge, hydration and affinity to the nanodiamonds. Small proteins (lysozyme) were found to form multilayers with significant conformational changes to screen the surface charge, while larger proteins (albumin) formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids.Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins

  15. A modified Poisson-Boltzmann equation applied to protein adsorption.

    Science.gov (United States)

    Gama, Marlon de Souza; Santos, Mirella Simões; Lima, Eduardo Rocha de Almeida; Tavares, Frederico Wanderley; Barreto, Amaro Gomes Barreto

    2018-01-05

    Ion-exchange chromatography has been widely used as a standard process in purification and analysis of protein, based on the electrostatic interaction between the protein and the stationary phase. Through the years, several approaches are used to improve the thermodynamic description of colloidal particle-surface interaction systems, however there are still a lot of gaps specifically when describing the behavior of protein adsorption. Here, we present an improved methodology for predicting the adsorption equilibrium constant by solving the modified Poisson-Boltzmann (PB) equation in bispherical coordinates. By including dispersion interactions between ions and protein, and between ions and surface, the modified PB equation used can describe the Hofmeister effects. We solve the modified Poisson-Boltzmann equation to calculate the protein-surface potential of mean force, treated as spherical colloid-plate system, as a function of process variables. From the potential of mean force, the Henry constants of adsorption, for different proteins and surfaces, are calculated as a function of pH, salt concentration, salt type, and temperature. The obtained Henry constants are compared with experimental data for several isotherms showing excellent agreement. We have also performed a sensitivity analysis to verify the behavior of different kind of salts and the Hofmeister effects. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Proteins at fluid interfaces: adsorption layers and thin liquid films.

    Science.gov (United States)

    Yampolskaya, Galina; Platikanov, Dimo

    2006-12-21

    A review in which many original published results of the authors as well as many other papers are discussed. The structure and some properties of the globular proteins are shortly presented, special accent being put on the alpha-chymotrypsin (alpha-ChT), lysozyme (LZ), human serum albumin (HSA), and bovine serum albumin (BSA) which have been used in the experiments with thin liquid films. The behaviour of protein adsorption layers (PAL) is extensively discussed. The dynamics of PAL formation, including the kinetics of adsorption as well as the time evolution of the surface tension of protein aqueous solutions, are considered. A considerable place is devoted to the surface tension and adsorption isotherms of the globular protein solutions, the simulation of PAL by interacting hard spheres, the experimental surface tension isotherms of the above mentioned proteins, and the interfacial tension isotherms for the protein aqueous solution/oil interface. The rheological properties of PAL at fluid interfaces are shortly reviewed. After a brief information about the experimental methods for investigation of protein thin liquid (foam or emulsion) films, the properties of the protein black foam films are extensively discussed: the conditions for their formation, the influence of the electrolytes and pH on the film type and stability, the thermodynamic properties of the black foam films, the contact angles film/bulk and their dynamic hysteresis. The next center of attention concerns some properties of the protein emulsion films: the conditions for formation of emulsion black films, the formation and development of a dimpling in microscopic, circular films. The protein-phospholipid mixed foam films are also briefly considered.

  17. [Inclusion of proteins into polyelectrolyte microcapsules by coprecipitation and adsorption].

    Science.gov (United States)

    Kochetkova, O Iu; Kazakova, L I; Moshkov, D A; Vinokurov, M G; Shabarchina, L I

    2013-01-01

    In present study microcapsules composed of synthetic (PSS and PAA) and biodegradable (DS and PAr) polyelectrolytes on calcium carbonate microparticles were obtained. The ultrastructural organization of biodegradable microcapsules was studied using transmission electron microscopy. The envelope of such capsules consisting of six polyelectrolyte layers is already well-formed, having the average thickness of 44 ± 3.0 nm, and their internal polyelectrolyte matrix is sparser compared to the synthetic microcapsules. Spectroscopy was employed to evaluate the efficiency of incorporation of FITC-labeled BSA into synthetic microcapsules by adsorption, depending on the number of polyelectrolyte layers. It was shown that the maximal amount of protein incorporated into the capsules with 6 or 7 polyelectrolyte layers (4 and 2 pg/capsule, correspondingly). As a result we conclude that, in comparison with co-precipitation, the use of adsorption allows to completely avoid the loss of protein upon encapsulation.

  18. Controlling nonspecific protein adsorption in a plug-based microfluidic system by controlling interfacial chemistry using fluorous-phase surfactants.

    Science.gov (United States)

    Roach, L Spencer; Song, Helen; Ismagilov, Rustem F

    2005-02-01

    Control of surface chemistry and protein adsorption is important for using microfluidic devices for biochemical analysis and high-throughput screening assays. This paper describes the control of protein adsorption at the liquid-liquid interface in a plug-based microfluidic system. The microfluidic system uses multiphase flows of immiscible fluorous and aqueous fluids to form plugs, which are aqueous droplets that are completely surrounded by fluorocarbon oil and do not come into direct contact with the hydrophobic surface of the microchannel. Protein adsorption at the aqueous-fluorous interface was controlled by using surfactants that were soluble in fluorocarbon oil but insoluble in aqueous solutions. Three perfluorinated alkane surfactants capped with different functional groups were used: a carboxylic acid, an alcohol, and a triethylene glycol group that was synthesized from commercially available materials. Using complementary methods of analysis, adsorption was characterized for several proteins (bovine serum albumin (BSA) and fibrinogen), including enzymes (ribonuclease A (RNase A) and alkaline phosphatase). These complementary methods involved characterizing adsorption in microliter-sized droplets by drop tensiometry and in nanoliter plugs by fluorescence microscopy and kinetic measurements of enzyme catalysis. The oligoethylene glycol-capped surfactant prevented protein adsorption in all cases. Adsorption of proteins to the carboxylic acid-capped surfactant in nanoliter plugs could be described by using the Langmuir model and tensiometry results for microliter drops. The microfluidic system was fabricated using rapid prototyping in poly(dimethylsiloxane) (PDMS). Black PDMS microfluidic devices, fabricated by curing a suspension of charcoal in PDMS, were used to measure the changes in fluorescence intensity more sensitively. This system will be useful for microfluidic bioassays, enzymatic kinetics, and protein crystallization, because it does not require

  19. Multilayer Choline Phosphate Molecule Modified Surface with Enhanced Cell Adhesion but Resistance to Protein Adsorption.

    Science.gov (United States)

    Chen, Xingyu; Yang, Ming; Liu, Botao; Li, Zhiqiang; Tan, Hong; Li, Jianshu

    2017-08-22

    Choline phosphate (CP), which is a new zwitterionic molecule, and has the reverse order of phosphate choline (PC) and could bind to the cell membrane though the unique CP-PC interaction. Here we modified a glass surface with multilayer CP molecules using surface-initiated atom-transfer radical polymerization (SI-ATRP) and the ring-opening method. Polymeric brushes of (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized by SI-ATRP from the glass surface. Then the grafted PDMAEMA brushes were used to introduce CP groups to fabricate the multilayer CP molecule modified surface. The protein adsorption experiment and cell culture test were used to evaluate the biocompatibility of the modified surfaces by using human umbilical veinendothelial cells (HUVECs). The protein adsorption results demonstrated that the multilayer CP molecule decorated surface could prevent the adsorption of fibrinogen and serum protein. The adhesion and proliferation of cells were improved significantly on the multilayer CP molecule modified surface. Therefore, the biocompatibility of the material surface could be improved by the modified multilayer CP molecule, which exhibits great potential for biomedical applications, e.g., scaffolds in tissue engineering.

  20. Adsorption of a small protein to a methyl-terminated hydrophobic surfaces

    DEFF Research Database (Denmark)

    Otzen, Daniel; Oliveberg, M.; Höök, F.

    2003-01-01

    We have studied the adsorption kinetics of a small monomeric protein S6 using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. Competitive adsorption from various proportions of native (Nat) and denatured (Den) protein in the bulk phase was carried out using a range...... of chemical denaturant concentrations. The ratio between Nat and Den in bulk has a profound affect on the adsorption behavior, most obvious from a significant (one order of magnitude) increase in the rate of a lag– and consolidation–adsorption phase when Nat is the major species present in bulk, signaling...... that these adsorption phases originates from the Den fraction of proteins in the bulk. To determine whether the kinetics of protein unfolding in the bulk phase are rate-limiting for adsorption of Nat, the adsorption kinetics of wildtype S6 with the mutant VA85 (whose unfolding kinetics are around 30 times more rapid...

  1. A comparison of the adsorption of saliva proteins and some typical proteins onto the surface of hydroxyapatite

    NARCIS (Netherlands)

    Kawasaki, K; Kambara, M; Matsumura, H; Norde, W

    2003-01-01

    Adsorption of protein from saliva on hydroxyapatite was compared with adsorption of several typical proteins with different electric charges, i.e. lysozyme, human serum albumin, beta-lactoglobulin and ovalbumin. Adsorbed amounts of these proteins were determined and electrophoretic mobilities of

  2. A comparison of the adsorption of saliva proteins and some typical proteins onto the surface of hydroxyapatite

    NARCIS (Netherlands)

    Kawasaki, K.; Kambara, M.; Matsumura, H.; Norde, W.

    2003-01-01

    Adsorption of protein from saliva on hydroxyapatite was compared with adsorption of several typical proteins with different electric charges, i.e. lysozyme, human serum albumin, @b-lactoglobulin and ovalbumin. Adsorbed amounts of these proteins were determined and electrophoretic mobilities of

  3. Decreased Bacterial Attachment and Protein Adsorption to Coatings Produced by Low Enegy Plasma Polymerization

    DEFF Research Database (Denmark)

    Andersen, T.E.; Kingshott, Peter; Benter, M.

    .figure) .and E. coli grown on uncoated silicone compared to PP-PVP coated silicone (right figure). Results from the flow chamber analysis shows PP-PVP to be very good at preventing E. coli colonization during prolonged growth in flow chamber. At this point other surfaces and bacteria remains to be tested...... adsorption and bacteria attachment/colonization. This is emphasized by the fact that long dwelling urinary catheters, which is a typical silicone medical device, causes 5% per day incidence of urinary tract infection [1,2]. A demand therefore exists for surface modifications providing the silicone material......-coated crystals were then treated with one of the plasma polymerized coatings. Adsorption of fibrinogen, human serum albumin or immunoglobulin G was measured using a QCM-D instrument [5] (model E4, Q-Sense AB, Vastra Frolunda, Sweden) using a solution of 50llg/1 protein in PBS buffer. Results and Discussion: Our...

  4. Increased adsorption of histidine-tagged proteins onto tissue culture polystyrene

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hansen, Thomas Steen; Lind, Johan Ulrik

    2012-01-01

    and ethylenediaminetetraacetic acid (EDTA), as well as adsorption performed at different pH and ionic strength indicates that the high adsorption is caused by electrostatic interaction between negatively charged carboxylate groups on the TCPS surface and positively charged histidine residues in the proteins. Pre......In this study we compare histidine-tagged and native proteins with regards to adsorption properties. We observe significantly increased adsorption of proteins with an incorporated polyhistidine amino acid motif (HIS-tag) onto tissue culture polystyrene (TCPS) compared to similar proteins without...... a HIS-tag. The effect is not observed on polystyrene (PS). Adsorption experiments have been performed at physiological pH (7.4) and the effect was only observed for the investigated proteins that have pI values below or around 7.4. Competitive adsorption experiments with imidazole...

  5. Hydrophilic crosslinked-polymeric surface capable of effective suppression of protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Kamon, Yuri; Inoue, Naoko; Mihara, Erika; Kitayama, Yukiya; Ooya, Tooru; Takeuchi, Toshifumi, E-mail: takeuchi@gold.kobe-u.ac.jp

    2016-08-15

    Highlights: • Three hydrophilic crosslinked polymers were examined for protein adsorption. • All polymers showed low nonspecific adsorption of negatively charged proteins. • Poly(MMPC) showed the lowest adsorption for positively charged proteins. • Poly(MMPC) is able to reduce nonspecific adsorption of a wide range of proteins. - Abstract: We investigated the nonspecific adsorption of proteins towards three hydrophilic crosslinked-polymeric thin layers prepared by surface-initiated atom transfer radical polymerization using N,N′-methylenebisacrylamide, 2-(methacryloyloxy)ethyl-[N-(2-methacryloyloxy)ethyl]phosphorylcholine (MMPC), or 6,6′-diacryloyl-trehalose crosslinkers. Protein binding experiments were performed by surface plasmon resonance with six proteins of different pI values including α-lactalbumin, bovine serum albumin (BSA), myoglobin, ribonuclease A, cytochrome C, and lysozyme in buffer solution at pH 7.4. All of the obtained crosslinked-polymeric thin layers showed low nonspecific adsorption of negatively charged proteins at pH 7.4 such as α-lactalbumin, BSA, and myoglobin. Nonspecific adsorption of positively charged proteins including ribonuclease A, cytochrome C, and lysozyme was the lowest for poly(MMPC). These results suggest poly(MMPC) can effectively reduce nonspecific adsorption of a wide range of proteins that are negatively or positively charged at pH 7.4. MMPC is a promising crosslinker for a wide range of polymeric materials requiring low nonspecific protein binding.

  6. Adsorption, aggregation, and desorption of proteins on smectite particles.

    Science.gov (United States)

    Kolman, Krzysztof; Makowski, Marcin M; Golriz, Ali A; Kappl, Michael; Pigłowski, Jacek; Butt, Hans-Jürgen; Kiersnowski, Adam

    2014-10-07

    We report on adsorption of lysozyme (LYS), ovalbumin (OVA), or ovotransferrin (OVT) on particles of a synthetic smectite (synthetic layered aluminosilicate). In our approach we used atomic force microscopy (AFM) and quartz crystal microbalance (QCM) to study the protein-smectite systems in water solutions at pH ranging from 4 to 9. The AFM provided insights into the adhesion forces of protein molecules to the smectite particles, while the QCM measurements yielded information about the amounts of the adsorbed proteins, changes in their structure, and conditions of desorption. The binding of the proteins to the smectite surface was driven mainly by electrostatic interactions, and hence properties of the adsorbed layers were controlled by pH. At high pH values a change in orientation of the adsorbed LYS molecules and a collapse or desorption of OVA layer were observed. Lowering pH to the value ≤ 4 caused LYS to desorb and swelling the adsorbed OVA. The stability of OVT-smectite complexes was found the lowest. OVT revealed a tendency to desorb from the smectite surface at all investigated pH. The minimum desorption rate was observed at pH close to the isoelectric point of the protein, which suggests that nonspecific interactions between OVT and smectite particles significantly contribute to the stability of these complexes.

  7. [Adsorption characteristics of proteins on membrane surface and effect of protein solution environment on permeation behavior of berberine].

    Science.gov (United States)

    Li, Yi-Qun; Xu, Li; Zhu, Hua-Xu; Tang, Zhi-Shu; Li, Bo; Pan, Yong-Lan; Yao, Wei-Wei; Fu, Ting-Ming; Guo, Li-Wei

    2017-10-01

    In order to explore the adsorption characteristics of proteins on the membrane surface and the effect of protein solution environment on the permeation behavior of berberine, berberine and proteins were used as the research object to prepare simulated solution. Low field NMR, static adsorption experiment and membrane separation experiment were used to study the interaction between the proteins and ceramic membrane or between the proteins and berberine. The static adsorption capacity of proteins, membrane relative flux, rejection rate of proteins, transmittance rate of berberine and the adsorption rate of proteins and berberine were used as the evaluation index. Meanwhile, the membrane resistance distribution, the particle size distribution and the scanning electron microscope (SEM) were determined to investigate the adsorption characteristics of proteins on ceramic membrane and the effect on membrane separation process of berberine. The results showed that the ceramic membrane could adsorb the proteins and the adsorption model was consistent with Langmuir adsorption model. In simulating the membrane separation process, proteins were the main factor to cause membrane fouling. However, when the concentration of proteins was 1 g•L⁻¹, the proteins had no significant effect on membrane separation process of berberine. Copyright© by the Chinese Pharmaceutical Association.

  8. Routine detection of calcium-binding proteins following their adsorption to nitrocellulose membrane filters

    International Nuclear Information System (INIS)

    Hincke, M.T.

    1988-01-01

    A routine semiquantitative procedure which permits soluble calcium-binding proteins to be detected following their adsorption to nitrocellulose membrane filters by liquid scintillation counting of specifically bound 45 Ca is described. Proteins with high affinity for calcium such as calmodulin and troponin can be detected with a detection threshold of about 2 μg per 400 μl. Modifications to decrease this limit are feasible and are discussed. This technique should allow calcium-binding proteins of unknown function to be assayed during their purification. It was necessary to treat solutions containing 45 Ca with chelex-100 in order to prevent loss of calcium binding which occurred as the decay product (SC 3+ ) accumulated, suggesting that all studies utilizing 45 Ca as a tracer should evaluate possible interference by this ion

  9. Protein adsorption capability on polyurethane and modified-polyurethane membrane for periodontal guided tissue regeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Sheikh, Zeeshan [Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Fitzgerald Building, 150 College Street, Toronto, ON M5S 3E2 (Canada); School of Engineering and Materials Science, Queen Mary, University of London, Mile End Rd, London, E1 4NS (United Kingdom); Khan, Abdul Samad, E-mail: draskhan@ciitlahore.edu.pk [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Roohpour, Nima [Oral Care R& D, GSK St., Georges Ave., Weybridge KT13 8PA (United Kingdom); Glogauer, Michael [Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Fitzgerald Building, 150 College Street, Toronto, ON M5S 3E2 (Canada); Rehman, Ihtesham u [Department of Materials Science and Engineering, The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom)

    2016-11-01

    Periodontal disease if left untreated can result in creation of defects within the alveolar ridge. Barrier membranes are frequently used with or without bone replacement graft materials for achieving periodontal guided tissue regeneration (GTR). Surface properties of barrier membranes play a vital role in their functionality and clinical success. In this study polyetherurethane (PEU) membranes were synthesized by using 4,4′-methylene-diphenyl diisocyanate (MDI), polytetramethylene oxide (PTMO) and 1,4-butane diol (BDO) as a chain extender via solution polymerization. Hydroxyl terminated polydimethylsiloxane (PDMS) due to having inherent surface orientation towards air was used for surface modification of PEU on one side of the membranes. This resulting membranes had one surface being PEU and the other being PDMS coated PEU. The prepared membranes were treated with solutions of bovine serum albumin (BSA) in de-ionized water at 37 °C at a pH of 7.2. The surface protein adsorptive potential of PEU membranes was observed using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Raman spectroscopy and Confocal Raman spectroscopy. The contact angle measurement, tensile strength and modulus of prepared membranes were also evaluated. PEU membrane (89.86 ± 1.62°) exhibited less hydrophobic behavior than PEU-PDMS (105.87 ± 3.16°). The ultimate tensile strength and elastic modulus of PEU (27 ± 1 MPa and 14 ± 2 MPa) and PEU-PDMS (8 ± 1 MPa and 26 ± 1 MPa) membranes was in required range. The spectral analysis revealed adsorption of BSA proteins on the surface of non PDMS coated PEU surface. The PDMS modified PEU membranes demonstrated a lack of BSA adsorption. The non PDMS coated side of the membrane which adsorbs proteins could potentially be used facing towards the defect attracting growth factors for periodontal tissue regeneration. Whereas, the PDMS coated side could serve as an occlusive barrier for preventing gingival epithelial

  10. Protein adsorption capability on polyurethane and modified-polyurethane membrane for periodontal guided tissue regeneration applications

    International Nuclear Information System (INIS)

    Sheikh, Zeeshan; Khan, Abdul Samad; Roohpour, Nima; Glogauer, Michael; Rehman, Ihtesham u

    2016-01-01

    Periodontal disease if left untreated can result in creation of defects within the alveolar ridge. Barrier membranes are frequently used with or without bone replacement graft materials for achieving periodontal guided tissue regeneration (GTR). Surface properties of barrier membranes play a vital role in their functionality and clinical success. In this study polyetherurethane (PEU) membranes were synthesized by using 4,4′-methylene-diphenyl diisocyanate (MDI), polytetramethylene oxide (PTMO) and 1,4-butane diol (BDO) as a chain extender via solution polymerization. Hydroxyl terminated polydimethylsiloxane (PDMS) due to having inherent surface orientation towards air was used for surface modification of PEU on one side of the membranes. This resulting membranes had one surface being PEU and the other being PDMS coated PEU. The prepared membranes were treated with solutions of bovine serum albumin (BSA) in de-ionized water at 37 °C at a pH of 7.2. The surface protein adsorptive potential of PEU membranes was observed using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Raman spectroscopy and Confocal Raman spectroscopy. The contact angle measurement, tensile strength and modulus of prepared membranes were also evaluated. PEU membrane (89.86 ± 1.62°) exhibited less hydrophobic behavior than PEU-PDMS (105.87 ± 3.16°). The ultimate tensile strength and elastic modulus of PEU (27 ± 1 MPa and 14 ± 2 MPa) and PEU-PDMS (8 ± 1 MPa and 26 ± 1 MPa) membranes was in required range. The spectral analysis revealed adsorption of BSA proteins on the surface of non PDMS coated PEU surface. The PDMS modified PEU membranes demonstrated a lack of BSA adsorption. The non PDMS coated side of the membrane which adsorbs proteins could potentially be used facing towards the defect attracting growth factors for periodontal tissue regeneration. Whereas, the PDMS coated side could serve as an occlusive barrier for preventing gingival epithelial

  11. Electrostatic interactions in protein adsorption probed by comparing lysozyme and succinylated lysozyme

    NARCIS (Netherlands)

    Veen, van der M.; Norde, W.; Cohen Stuart, M.A.

    2004-01-01

    The influence of electrostatic interactions on protein adsorption was studied by comparing the adsorption of lysozyme and succinylated lysozyme at silica surfaces. The succinylation affects the charge of the protein, but also the stability. Although changes in stability can have an influence on

  12. Protein adsorption at nanopatterned surfaces studied by QCM-D and SPR

    DEFF Research Database (Denmark)

    Kristensen, Stine; Pedersen, Gitte Albinus; Nejsum, Lene Niemann

    2013-01-01

    This paper presents the use of the quartz microbalance with dissipation combined with surface plasmon resonance to probe protein adsorption at nanopatterned surfaces. Three different types of adsorbing materials, representing rigid discrete nanoparticles, dense protein films and soft low density ...

  13. The adsorption features between insecticidal crystal protein and nano-Mg(OH)2.

    Science.gov (United States)

    Pan, Xiaohong; Xu, Zhangyan; Zheng, Yilin; Huang, Tengzhou; Li, Lan; Chen, Zhi; Rao, Wenhua; Chen, Saili; Hong, Xianxian; Guan, Xiong

    2017-12-01

    Nano-Mg(OH) 2 , with low biological toxicity, is an ideal nano-carrier for insecticidal protein to improve the bioactivity. In this work, the adsorption features of insecticidal protein by nano-Mg(OH) 2 have been studied. The adsorption capacity could reach as high as 136 mg g -1 , and the adsorption isotherm had been fitted with Langmuir and Freundlich models. Moreover, the adsorption kinetics followed a pseudo-first or -second order rate model, and the adsorption was spontaneous and an exothermic process. However, high temperatures are not suitable for adsorption, which implies that the temperature would be a critical factor during the adsorption process. In addition, FT-IR confirmed that the protein was adsorbed on the nano-Mg(OH) 2 , zeta potential analysis suggested that insecticidal protein was loaded onto the nano-Mg(OH) 2 not by electrostatic adsorption but maybe by intermolecular forces, and circular dichroism spectroscopy of Cry11Aa protein before and after loading with nano-Mg(OH) 2 was changed. The study applied the adsorption information between Cry11Aa and nano-Mg(OH) 2 , which would be useful in the practical application of nano-Mg(OH) 2 as a nano-carrier.

  14. Increased adsorption of histidine-tagged proteins onto tissue culture polystyrene.

    Science.gov (United States)

    Holmberg, Maria; Hansen, Thomas Steen; Lind, Johan Ulrik; Hjortø, Gertrud Malene

    2012-04-01

    In this study we compare histidine-tagged and native proteins with regards to adsorption properties. We observe significantly increased adsorption of proteins with an incorporated polyhistidine amino acid motif (HIS-tag) onto tissue culture polystyrene (TCPS) compared to similar proteins without a HIS-tag. The effect is not observed on polystyrene (PS). Adsorption experiments have been performed at physiological pH (7.4) and the effect was only observed for the investigated proteins that have pI values below or around 7.4. Competitive adsorption experiments with imidazole and ethylenediaminetetraacetic acid (EDTA), as well as adsorption performed at different pH and ionic strength indicates that the high adsorption is caused by electrostatic interaction between negatively charged carboxylate groups on the TCPS surface and positively charged histidine residues in the proteins. Pre-adsorption of bovine serum albumin (BSA) does not decrease the adsorption of HIS-tagged proteins onto TCPS. Our findings identify a potential problem in using HIS-tagged signalling molecule in assays with cells cultured on TCPS, since the concentration of the molecule in solution might be affected and this could critically influence the assay outcome. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. A KINETIC MODEL FOR MONO-LAYER GLOBULAR PROTEIN ADSORPTION ON SOLID/LIQUID INTERFACES

    Directory of Open Access Journals (Sweden)

    Kamal I. M. Al-Malah

    2012-12-01

    Full Text Available A kinetic model was derived for globular protein adsorption. The model takes into account the three possible scenarios of a protein molecule in solution, being exposed to an interface: adsorption step from the solution to the interface; the possible desorption back into the solution; and the surface-induced unfolding or spreading of the protein unto the substrate surface. A globular protein molecule is visualized as a sphere with radius D. In addition to the general case of protein adsorption, which portrays either the surface coverage (Theta or surface concentration (� as a function of the adsorption time, special cases, like equilibrium condition, lowsurface coverage, irreversible, and Langmuirian were also presented and treated in light of the derived model. The general model was simplified for each of the subset cases. The irreversibility versus reversibility of protein adsorption was discussed. The substrate surface energetics or effects are accounted for via the proposition of the percent relative change in D/V ratio for the adsorbing protein, called (D/VPRC parameter. (D/VPRC is calculated with respect to the monolayer surface concentration of protein, where the latter is given by D/Vratio. This can be used as a landmark to protein adsorption isotherms or even kinetics. This is visualized as an indicator for solid substrate effects on the adsorbing proteins. (D/VPRC can be zero (fresh monolayer, negative (aged monolayer, or positive (multi-layer. The reference surface concentration is reported for some selected proteins.

  16. Protein Adsorption to In-Line Filters of Intravenous Administration Sets.

    Science.gov (United States)

    Besheer, Ahmed

    2017-10-01

    Ensuring compatibility of administered therapeutic proteins with intravenous administration sets is an important regulatory requirement. A low-dose recovery during administration of low protein concentrations is among the commonly observed incompatibilities, and it is mainly due to adsorption to in-line filters. To better understand this phenomenon, we studied the adsorption of 4 different therapeutic proteins (2 IgG1s, 1 IgG4, and 1 Fc fusion protein) diluted to 0.01 mg/mL in 5% glucose (B. Braun EcoFlac; B. Braun Melsungen AG, Melsungen, Germany) or 0.9% sodium chloride (NaCl; Freeflex; Fresenius Kabi, Friedberg, Germany) solutions to 8 in-line filters (5 positively charged and 3 neutral filters made of different polymers and by different suppliers). The results show certain patterns of protein adsorption, which depend to a large extent on the dilution solution and filter material, and to a much lower extent on the proteins' biophysical properties. Investigation of the filter membranes' zeta potential showed a correlation between the observed adsorption pattern in 5% glucose solution and the filter's surface charge, with higher protein adsorption for the strongly negatively charged membranes. In 0.9% NaCl solution, the surface charges are masked, leading to different adsorption patterns. These results contribute to the general understanding of the protein adsorption to IV infusion filters and allow the design of more efficient compatibility studies. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  17. AFM study of adsorption of protein A on a poly(dimethylsiloxane) surface

    International Nuclear Information System (INIS)

    Yu Ling; Lu Zhisong; Gan Ye; Liu Yingshuai; Li, C M

    2009-01-01

    In this paper, the morphology and kinetics of adsorption of protein A on a PDMS surface is studied by AFM. The results of effects of pH, protein concentration and contact time of the adsorption reveal that the morphology of adsorbed protein A is significantly affected by pH and adsorbed surface concentration, in which the pH away from the isoelectric point (IEP) of protein A could produce electrical repulsion to change the protein conformation, while the high adsorbed surface protein volume results in molecular networks. Protein A can form an adsorbed protein film on PDMS with a maximum volume of 2.45 x 10 -3 μm 3 . This work enhances our fundamental understanding of protein A adsorption on PDMS, a frequently used substrate component in miniaturized immunoassay devices.

  18. Protein Adsorption to Titanium and Zirconia Using a Quartz Crystal Microbalance Method

    Directory of Open Access Journals (Sweden)

    You Kusakawa

    2017-01-01

    Full Text Available Protein adsorption onto titanium (Ti or zirconia (ZrO2 was evaluated using a 27 MHz quartz crystal microbalance (QCM. As proteins, fibronectin (Fn, a cell adhesive protein, and albumin (Alb, a cell adhesion-inhibiting protein, were evaluated. The Ti and ZrO2 sensors for QCM were characterized by atomic force microscopy and electron probe microanalysis observation, measurement of contact angle against water, and surface roughness. The amounts of Fn and Alb adsorbed onto the Ti and ZrO2 sensors and apparent reaction rate were obtained using QCM measurements. Ti sensor showed greater adsorption of Fn and Alb than the ZrO2 sensor. In addition, amount of Fn adsorbed onto the Ti or ZrO2 sensors was higher than that of Alb. The surface roughness and hydrophilicity of Ti or ZrO2 may influence the adsorption of Fn or Alb. With regard to the adsorption rate, Alb adsorbed more rapidly than Fn onto Ti. Comparing Ti and ZrO2, Alb adsorption rate to Ti was faster than that to ZrO2. Fn adsorption will be effective for cell activities, but Alb adsorption will not. QCM method could simulate in vivo Fn and Alb adsorption to Ti or ZrO2.

  19. Evaluations of cellulose accessibilities of lignocelluloses by solute exclusion and protein adsorption techniques

    Science.gov (United States)

    Q.Q. Wang; Z. He; Z. Zhu; Y.-H.P. Zhang; Y. Ni; X.L. Luo; J.Y. Zhu

    2012-01-01

    Cellulose accessibilities of a set of hornified lignocellulosic substrates derived by drying the never dried pretreated sample and a set of differently pretreated lodgepople pine substrates, were evaluated using solute exclusion and protein adsorption methods. Direct measurements of cellulase adsorption onto cellulose surface of the set of pretreated substrates were...

  20. Use of polysaccharides to control protein adsorption to the air-water interface

    NARCIS (Netherlands)

    Ganzevles, R.A.; Cohen Stuart, M.A.; Vliet, T.v.; Jongh, H.H.J.de

    2006-01-01

    In order to understand foaming behaviour of mixed protein/anionic polysaccharide solutions, we investigated the effect of β-lactoglobulin/pectin interaction in the bulk on β-lactoglobulin adsorption to the air-water interface. Adsorption kinetics were evaluated by following surface pressure

  1. Evaluation of protein adsorption onto a polyurethane nanofiber surface having different segment distributions

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Yuko; Koizumi, Gaku [Frontier Fiber Technology and Science, Graduate School of Engineering, University of Fukui (Japan); Sakamoto, Hiroaki, E-mail: hi-saka@u-fukui.ac.jp [Tenure-Track Program for Innovative Research, University of Fukui (Japan); Suye, Shin-ichiro [Frontier Fiber Technology and Science, Graduate School of Engineering, University of Fukui (Japan)

    2017-02-01

    Electrospinning is well known to be an effective method for fabricating polymeric nanofibers with a diameter of several hundred nanometers. Recently, the molecular-level orientation within nanofibers has attracted particular attention. Previously, we used atomic force microscopy to visualize the phase separation between soft and hard segments of a polyurethane (PU) nanofiber surface prepared by electrospinning. The unstretched PU nanofibers exhibited irregularly distributed hard segments, whereas hard segments of stretched nanofibers prepared with a high-speed collector exhibited periodic structures along the long-axis direction. PU was originally used to inhibit protein adsorption, but because the surface segment distribution was changed in the stretched nanofiber, here, we hypothesized that the protein adsorption property on the stretched nanofiber might be affected. We investigated protein adsorption onto PU nanofibers to elucidate the effects of segment distribution on the surface properties of PU nanofibers. The amount of adsorbed protein on stretched PU nanofibers was increased compared with that of unstretched nanofibers. These results indicate that the hard segment alignment on stretched PU nanofibers mediated protein adsorption. It is therefore expected that the amount of protein adsorption can be controlled by rotation of the collector. - Highlights: • The hard segments of stretched PU nanofibers exhibit periodic structures. • The adsorbed protein on stretched PU nanofibers was increased compared with PU film. • The hard segment alignment on stretched PU nanofibers mediated protein adsorption.

  2. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

    Full Text Available Application of saw dust for the removal of an anionic dye, tartrazine, from aqueous solutions has been investigated. The experiments were carried out in batch mode. Effect of the parameters such as pH, initial dye concentration and temperature on the removal of the dye was studied. Equilibrium was achieved in 70 min. Maximum adsorption of dye was achieved at pH 3. Removal percent was found to be dependent on the initial concentration of dye solution, and maximum removal was found to be 97% at 1 mg/L of tartrazine. The removal increases from 71% to 97% when the initial concentration of dye solution decreases from 15 mg/L to 1 mg/L. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The (Langmuir adsorption capacity of the adsorbent is found to be 4.71 mg/g at 318 K. Kinetic modeling of the process of removal was carried out and the process of removal was found to follow a pseudo second order model and the value of rate constant for adsorption process was calculated as 2.7 × 10−3 g mg−1 min−1 at 318 K. The thermodynamic parameters such as change in free energy (ΔG°, enthalpy (ΔH° and entropy (ΔS° were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. Further, the values of ΔH° indicated the endothermic nature of the process of removal.

  3. Competitive Adsorption of Plasma Proteins on Polysaccharide-Modified Silicon Surfaces

    National Research Council Canada - National Science Library

    Ombelli, Michela; Costello, Lauren B; Meng, Qing C; Composto, Russell J; Eckmann, David M

    2005-01-01

    .... Competitive protein adsorption plays a key role in the hemocompatibility of the surface. The synthesis of nonfouling surfaces is therefore one of the major prerequisites for devices for biomedical applications...

  4. Correlation Study of PVDF Membrane Morphology with Protein Adsorption: Quantitative Analysis by FTIR/ATR Technique

    Science.gov (United States)

    Ideris, N.; Ahmad, A. L.; Ooi, B. S.; Low, S. C.

    2018-05-01

    Microporous PVDF membranes were used as protein capture matrices in immunoassays. Because the most common labels in immunoassays were detected based on the colour change, an understanding of how protein concentration varies on different PVDF surfaces was needed. Herein, the correlation between the membrane pore size and protein adsorption was systematically investigated. Five different PVDF membrane morphologies were prepared and FTIR/ATR was employed to accurately quantify the surface protein concentration on membranes with small pore sizes. SigmaPlot® was used to find a suitable curve fit for protein adsorption and membrane pore size, with a high correlation coefficient, R2, of 0.9971.

  5. Protein Adsorption and Antibacterial Behavior for Hydroxyapatite Nanocrystals Prepared by Hydrothermal Method

    OpenAIRE

    笠原, 英充; 小形, 信男; 荻原, 隆

    2005-01-01

    Homogeneous hydroxyapatite nanocrystals which have aspect ratio with more than four were synthesized by hydrothermal method. X-ray fluorescence analysis revealed that the Ca/P ratio of hydroxyapatite nanocrystals was maintaining start composition. The protein adsorption properties and bacteria-resistant of hydroxyapatite nanocrystals were investigated. The protein adsorption properties of hydroxyapatite nanocrystals were improvement after the hydrothermal treatment. Bacteria-resistant behavio...

  6. Regular Nanoscale Protein Patterns via Directed Adsorption through Self-Assembled DNA Origami Masks.

    Science.gov (United States)

    Ramakrishnan, Saminathan; Subramaniam, Sivaraman; Stewart, A Francis; Grundmeier, Guido; Keller, Adrian

    2016-11-16

    DNA origami has become a widely used method for synthesizing well-defined nanostructures with promising applications in various areas of nanotechnology, biophysics, and medicine. Recently, the possibility to transfer the shape of single DNA origami nanostructures into different materials via molecular lithography approaches has received growing interest due to the great structural control provided by the DNA origami technique. Here, we use ordered monolayers of DNA origami nanostructures with internal cavities on mica surfaces as molecular lithography masks for the fabrication of regular protein patterns over large surface areas. Exposure of the masked sample surface to negatively charged proteins results in the directed adsorption of the proteins onto the exposed surface areas in the holes of the mask. By controlling the buffer and adsorption conditions, the protein coverage of the exposed areas can be varied from single proteins to densely packed monolayers. To demonstrate the versatility of this approach, regular nanopatterns of four different proteins are fabricated: the single-strand annealing proteins Redβ and Sak, the iron-storage protein ferritin, and the blood protein bovine serum albumin (BSA). We furthermore demonstrate the desorption of the DNA origami mask after directed protein adsorption, which may enable the fabrication of hierarchical patterns composed of different protein species. Because selectivity in adsorption is achieved by electrostatic interactions between the proteins and the exposed surface areas, this approach may enable also the large-scale patterning of other charged molecular species or even nanoparticles.

  7. Proteins at interfaces : the adsorption of human plasma albumin and bovine pancreas ribonuclease on polystyrene latices

    NARCIS (Netherlands)

    Norde, W.

    1976-01-01

    The adsorption from (aqueous) solution of proteins is very complex. The interfacial behaviour of proteins is determined by the properties of, and the mutual interactions between, the adsorbing interface, the protein molecules, the solvent (water) molecules and other solutes (e.g. ions).

  8. Equilibrium of adsorption of mixed milk protein/surfactant solutions at the water/air interface.

    Science.gov (United States)

    Kotsmar, C; Grigoriev, D O; Xu, F; Aksenenko, E V; Fainerman, V B; Leser, M E; Miller, R

    2008-12-16

    Ellipsometry and surface profile analysis tensiometry were used to study and compare the adsorption behavior of beta-lactoglobulin (BLG)/C10DMPO, beta-casein (BCS)/C10DMPO and BCS/C12DMPO mixtures at the air/solution interface. The adsorption from protein/surfactant mixed solutions is of competitive nature. The obtained adsorption isotherms suggest a gradual replacement of the protein molecules at the interface with increasing surfactant concentration for all studied mixed systems. The thickness, refractive index, and the adsorbed amount of the respective adsorption layers, determined by ellipsometry, decrease monotonically and reach values close to those for a surface covered only by surfactant molecules, indicating the absence of proteins from a certain surfactant concentration on. These results correlate with the surface tension data. A continuous increase of adsorption layer thickness was observed up to this concentration, caused by the desorption of segments of the protein and transforming the thin surface layer into a rather diffuse and thick one. Replacement and structural changes of the protein molecules are discussed in terms of protein structure and surface activity of surfactant molecules. Theoretical models derived recently were used for the quantitative description of the equilibrium state of the mixed surface layers.

  9. A study on poly (N-vinyl-2-pyrrolidone covalently bonded NiTi surface for inhibiting protein adsorption

    Directory of Open Access Journals (Sweden)

    Hongyan Yu

    2016-12-01

    Full Text Available Near equiatomic NiTi alloys have been extensively applied as biomaterials owing to its unique shape memory effect, superelasticity and biocompatibility. It has been demonstrated that surfaces capable of preventing plasma protein adsorption could reduce the reactivity of biomaterials with human blood. This motivated a lot of researches on the surface modification of NiTi alloy. In the present work, following heat and alkaline treatment and silanization by trichlorovinylsilane (TCVS, coating of poly (N-vinyl-2-pyrrolidone (PVP was produced on the NiTi alloy by gamma ray induced chemical bonding. The structures and properties of modified NiTi were characterized and in vitro biocompatibility of plasma protein adsorption was investigated. The results indicated that heat treatment at 823 K for 1 h could result in the formation of a protective TiO2 layer with “Ni-free” zone on NiTi surface. It was found that PVP was covalently bonded on NiTi surface to create a hydrophilic layer for inhibiting protein adsorption on the surface. The present work offers a green approach to introduce a bioorganic surface on metal and other polymeric or inorganic substrates by gamma irradiation.

  10. Hydrogel covered bimetallic Co:Ni magnetic nano alloy for protein adsorption in biomedical application

    Science.gov (United States)

    Rajar, Kausar; Alveroglu, Esra

    2017-10-01

    In this study, polyacrylamide (PAAm) hydrogel covered CoNi magnetic nanoalloys with various Co/Ni molar ratio (from 1/4 to 4/1) were synthesized, characterized and used for adsorption of Bovine Serum Albumin (BSA). XRD, EDS, VSM, SEM, AFM, Automated Gas Sorption Analyzer and Fluorescence measurements were used for characterizations and adsorption studies. The results confirm that all the synthesized nanoalloys have soft ferromagnetic nature and particles size were determined to be in the range of 8.60-12.19 nm. Adsorption performances of magnetic nanoalloys were investigated on bovine serum albumin (BSA) as a model protein. The results showed that prepared CoNi:PAAm composites have multistage adsorption kinetics for BSA and increasing Ni content in the CoNi nanoalloys enhance the adsorption rate constant and the rate constant can be tuned between 0.003 s-1 and 0.009 s-1 and between 0.01 s-1 and 0.60 s-1 for the first order adsorption and the second order adsorption stages, respectively. These results show that CoNi:PAAm composites can open new pathways for preparing a special composite material which has specific adsorption kinetic for bio-separation technology.

  11. AFM-based force spectroscopy on polystyrene brushes: effect of brush thickness on protein adsorption.

    Science.gov (United States)

    Hentschel, Carsten; Wagner, Hendrik; Smiatek, Jens; Heuer, Andreas; Fuchs, Harald; Zhang, Xi; Studer, Armido; Chi, Lifeng

    2013-02-12

    Herein we present a study on nonspecific binding of proteins at highly dense packed hydrophobic polystyrene brushes. In this context, an atomic force microscopy tip was functionalized with concanavalin A to perform single-molecule force spectroscopy measurements on polystyrene brushes with thicknesses of 10 and 60 nm, respectively. Polystyrene brushes with thickness of 10 nm show an almost two times stronger protein adsorption than brushes with a thickness of 60 nm: 72 pN for the thinner and 38 pN for the thicker layer, which is in qualitative agreement with protein adsorption studies conducted macroscopically by fluorescence microscopy.

  12. Surface-water interface induces conformational changes critical for protein adsorption: Implications for monolayer formation of EAS hydrophobin

    Directory of Open Access Journals (Sweden)

    Kamron eLey

    2015-11-01

    Full Text Available The class I hydrophobin EAS is part of a family of small, amphiphilic fungal proteins best known for their ability to self-assemble into stable monolayers that modify the hydrophobicity of a surface to facilitate further microbial growth. These proteins have attracted increasing attention for industrial and biomedical applications, with the aim of designing surfaces that have the potential to maintain their clean state by resisting non-specific protein binding. To gain a better understanding of this process, we have employed all-atom molecular dynamics to study initial stages of the spontaneous adsorption of monomeric EAS hydrophobin on fully hydroxylated silica, a commonly used industrial and biomedical substrate. Particular interest has been paid to the Cys3-Cys4 loop, which has been shown to exhibit disruptive behavior in solution, and the Cys7-Cys8 loop, which is believed to be involved in the aggregation of EAS hydrophobin at interfaces. Specific and water mediated interactions with the surface were also analyzed. We have identified two possible binding motifs, one which allows unfolding of the Cys7-Cys8 loop due to the surfactant-like behavior of the Cys3-Cys4 loop, and another which has limited unfolding due to the Cys3-Cys4 loop remaining disordered in solution. We have also identified intermittent interactions with water which mediate the protein adsorption to the surface, as well as longer lasting interactions which control the diffusion of water around the adsorption site. These results have shown that EAS behaves in a similar way at the air-water and surface-water interfaces, and have also highlighted the need for hydrophilic ligand functionalization of the silica surface in order to prevent the adsorption of EAS hydrophobin.

  13. Study on protein conformation and adsorption behaviors in nanodiamond particle-protein complexes

    International Nuclear Information System (INIS)

    Wang Haidong; Niu, Catherine Hui; Yang Qiaoqin; Badea, Ildiko

    2011-01-01

    In the present research, the conformation of bovine serum albumin (BSA) in the nanodiamond particle (ND)-BSA complex was studied by Fourier transform infrared spectroscopy, fluorescence spectroscopy, UV-vis spectroscopy, and circular dichroism spectroscopy. The spectroscopic study revealed that most BSA structural features could be preserved in the complex though the BSA underwent conformational changes in the complex due to ND-BSA interaction. In addition, BSA adsorption isotherms and zeta-potential measurements were employed to investigate the pH dependence of the ND-BSA interaction. The changes in surface charge of the ND-BSA complex with pH variations indicated that the binding of BSA to ND might lead to not only the adsorption of BSA onto the ND surface but also the partial breakup of ND aggregates into relatively small ND-BSA aggregates because of the strong binding force between ND and BSA. The results show that ND is an excellent platform for protein immobilization with high affinity and holds great potential to be used for biosensor applications.

  14. Study on protein conformation and adsorption behaviors in nanodiamond particle-protein complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Haidong [Department of Biomedical Engineering, University of Saskatchewan, Saskatoon, S7N 5A9 (Canada); Niu, Catherine Hui [Department of Chemical Engineering, University of Saskatchewan, Saskatoon, S7N 5A9 (Canada); Yang Qiaoqin [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, S7N 5A9 (Canada); Badea, Ildiko, E-mail: catherine.niu@usask.ca [Drug Design and Discovery Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, S7N 5C9 (Canada)

    2011-04-08

    In the present research, the conformation of bovine serum albumin (BSA) in the nanodiamond particle (ND)-BSA complex was studied by Fourier transform infrared spectroscopy, fluorescence spectroscopy, UV-vis spectroscopy, and circular dichroism spectroscopy. The spectroscopic study revealed that most BSA structural features could be preserved in the complex though the BSA underwent conformational changes in the complex due to ND-BSA interaction. In addition, BSA adsorption isotherms and zeta-potential measurements were employed to investigate the pH dependence of the ND-BSA interaction. The changes in surface charge of the ND-BSA complex with pH variations indicated that the binding of BSA to ND might lead to not only the adsorption of BSA onto the ND surface but also the partial breakup of ND aggregates into relatively small ND-BSA aggregates because of the strong binding force between ND and BSA. The results show that ND is an excellent platform for protein immobilization with high affinity and holds great potential to be used for biosensor applications.

  15. Effect of thermal stability on protein adsorption to silica using homologous aldo-keto reductases.

    Science.gov (United States)

    Felsovalyi, Flora; Patel, Tushar; Mangiagalli, Paolo; Kumar, Sanat K; Banta, Scott

    2012-08-01

    Gaining more insight into the mechanisms governing the behavior of proteins at solid/liquid interfaces is particularly relevant in the interaction of high-value biologics with storage and delivery device surfaces, where adsorption-induced conformational changes may dramatically affect biocompatibility. The impact of structural stability on interfacial behavior has been previously investigated by engineering nonwild-type stability mutants. Potential shortcomings of such approaches include only modest changes in thermostability, and the introduction of changes in the topology of the proteins when disulfide bonds are incorporated. Here we employ two members of the aldo-keto reductase superfamily (alcohol dehydrogenase, AdhD and human aldose reductase, hAR) to gain a new perspective on the role of naturally occurring thermostability on adsorbed protein arrangement and its subsequent impact on desorption. Unexpectedly, we find that during initial adsorption events, both proteins have similar affinity to the substrate and undergo nearly identical levels of structural perturbation. Interesting differences between AdhD and hAR occur during desorption and both proteins exhibit some level of activity loss and irreversible conformational change upon desorption. Although such surface-induced denaturation is expected for the less stable hAR, it is remarkable that the extremely thermostable AdhD is similarly affected by adsorption-induced events. These results question the role of thermal stability as a predictor of protein adsorption/desorption behavior. Copyright © 2012 The Protein Society.

  16. Adsorptive loss of secreted recombinant proteins in transgenic rice cell suspension cultures.

    Science.gov (United States)

    Kwon, Jun-Young; Lee, Kyoung-Hoon; Cheon, Su-Hwan; Ryu, Hyun-Nam; Kim, Sun Jin; Kim, Dong-Il

    2012-03-01

    Adsorptive loss of human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) in transgenic rice cell suspension cultures was investigated using glass flasks, plastic flasks, disposable vessels, and stainless steel vessels. When hCTLA4Ig was added to the glass flasks containing sterile AA medium, a rapid decrease in the concentration of hCTLA4Ig, independent on pH, was observed resulting in more than 90% of the protein loss within 1 h due to the surface adsorption. When the same experiments were performed on four different types of culture equipments mentioned above, the lowest adsorption level was observed in the plastic flasks and the highest level was observed in the glass flasks. The use of the plastic flasks retarded the adsorptive loss of hCTLA4Ig at the early stage of the protein production. There was a significant increase in the production of hCTLA4Ig when the flasks were coated with bovine serum albumin. However, the spike test of purified hCTLA4Ig at two different concentrations of 15 and 100 mg L(-1) in 500-mL spinner flasks confirmed that the amount of hCTLA4Ig adsorbed was dependent on the surface area of the flasks but not on the concentrations. In conclusion, although the protein adsorption affected the total amount of the protein yielded to some extent, it could be regarded as a minor factor in transgenic plant cell cultures with higher titer.

  17. Protein adsorption on low temperature alpha alumina films for surgical instruments

    Energy Technology Data Exchange (ETDEWEB)

    Cloud, A.N., E-mail: acloud@uark.ed [University of Arkansas, Fayetteville, AR 72701 (United States); Kumar, S. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia); Kavdia, M.; Abu-Safe, H.H.; Gordon, M.H. [University of Arkansas, Fayetteville, AR 72701 (United States)

    2009-08-31

    Bulk alumina has been shown to exhibit reduced protein adsorption, a property that can be exploited for developing alumina-coated surgical instruments and devices. Alpha alumina thin films were deposited on surgical stainless steel substrates to investigate the adsorption of a model protein (BSA, bovine serum albumin). The films were deposited at 480 {sup o}C by AC inverted cylindrical magnetron sputtering. Films were obtained at 6 kW and 50% oxygen partial pressure by volume. The presence of alpha-phase alumina has been shown by transmission electron microscopy. Results indicate that there was a 50% reduction in protein adsorption for samples with the alumina coating compared to those with no coating.

  18. Adsorption, desorption and biodegradation in soil of CrylAb toxin protein from Bt transgenic rice

    International Nuclear Information System (INIS)

    Wang Haiyan; Ye Qingfu

    2004-01-01

    The equilibrium adsorption and binding of CrylAb toxin from Bt transgenic rice, to 7 different soils and the biodegradation of the bound toxin were studied. The adsorption rate of Bt in soils improved with decreasing of the added Bt purified protein concentration. Adsorption rate (125 and 780 nm/ml) in powdery-muddy paddy soil, Fluvio-marine yellow loamy and Coastal saline soil were 24.85% and 40.81%, 9.1% and 31.67%, 12.47% and 30.75%, respectively. Desorption rate in the soils dropped with content of soil-absorbed protein decreased. Its adsorption ratio in powdery-muddy paddy soil was 12.95% and 5.88%, respectively. The relationship between adsorption amount and concentration of Bt purified protein in different soils was notably positive correlation (P 0 e -λt ); Half life of Bt protein in soils was among 15.2-97.6 d; Degradation of pruified Bt protein was rapid at the initial incubation time (30 d), but slow at 150d incubation; The degradation of purified Bt protein in Intertidal sandy soil was the slowest with half-life of 97.6d. The protein in the soil amended with 1.25 μg/g could be still detectable after incubation of 345d; the degradation of purified Bt protein in Coastal saline soil and Aquic light saline sandy soil were faster. Their half-lives were 19.6 d and 15.2 d, respecitvely. The residue time of Bt purified protein in the soils was all more than 150 d. (authors)

  19. Kinetics of protein adsorption/desorption mediated by pH-responsive polymer layer

    Science.gov (United States)

    Su, Xiao-Hang; Lei, Qun-Li; Ren, Chun-Lai

    2015-11-01

    We propose a new way of regulating protein adsorption by using a pH-responsive polymer. According to the theoretical results obtained from the molecular theory and kinetic approaches, both thermodynamics and kinetics of protein adsorption are verified to be well controlled by the solution pH. The kinetics and the amount of adsorbed proteins at equilibrium are greatly increased when the solution environment changes from acid to neutral. The reason is that the increased pH promotes the dissociation of the weak polyelectrolyte, resulting in more charged monomers and more stretched chains. Thus the steric repulsion within the polymer layer is weakened, which effectively lowers the barrier felt by the protein during the process of adsorption. Interestingly, we also find that the kinetics of protein desorption is almost unchanged with the variation of pH. It is because although the barrier formed by the polymer layer changes along with the change of pH, the potential at contact with the surface varies equally. Our results may provide useful insights into controllable protein adsorption/desorption in practical applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 21274062, 11474155, and 91027040).

  20. Kinetics of protein adsorption/desorption mediated by pH-responsive polymer layer

    International Nuclear Information System (INIS)

    Su Xiao-Hang; Lei Qun-Li; Ren Chun-Lai

    2015-01-01

    We propose a new way of regulating protein adsorption by using a pH-responsive polymer. According to the theoretical results obtained from the molecular theory and kinetic approaches, both thermodynamics and kinetics of protein adsorption are verified to be well controlled by the solution pH. The kinetics and the amount of adsorbed proteins at equilibrium are greatly increased when the solution environment changes from acid to neutral. The reason is that the increased pH promotes the dissociation of the weak polyelectrolyte, resulting in more charged monomers and more stretched chains. Thus the steric repulsion within the polymer layer is weakened, which effectively lowers the barrier felt by the protein during the process of adsorption. Interestingly, we also find that the kinetics of protein desorption is almost unchanged with the variation of pH. It is because although the barrier formed by the polymer layer changes along with the change of pH, the potential at contact with the surface varies equally. Our results may provide useful insights into controllable protein adsorption/desorption in practical applications. (paper)

  1. Sputter deposited bioceramic coatings: surface characterisation and initial protein adsorption studies using surface-MALDI-MS

    DEFF Research Database (Denmark)

    Boyd, A. R.; Burke, G. A.; Duffy, H.

    2011-01-01

    Protein adsorption onto calcium phosphate (Ca–P) bioceramics utilised in hard tissue implant applications has been highlighted as one of the key events that influences the subsequent biological response, in vivo. This work reports on the use of surface-matrix assisted laser desorption ionisation...... to a combination of growth factors and lipoproteins present in serum. From the data obtained here it is evident that surface-MALDI-MS has significant utility as a tool for studying the dynamic nature of protein adsorption onto the surfaces of bioceramic coatings, which most likely plays a significant role...

  2. Influence of surface features of hydroxyapatite on the adsorption of proteins relevant to bone regeneration.

    Science.gov (United States)

    Fernández-Montes Moraleda, Belén; San Román, Julio; Rodríguez-Lorenzo, Luís M

    2013-08-01

    Protein-surface interaction may determine the success or failure of an implanted device. Not much attention have been paid to the specific surface parametes of hydroxyapatite (OHAp) that modulates and determines the formation and potential activity of the layer of proteins that is first formed when the material get in contact with the host tissue. the influence of specific surface area (SSA), crystallite size (CS) and particle size (PS) of OHAp on the adsorption of proteins relevant for bone regeneration is evaluated in this article. OHAp have been prepared by a wet chemical reaction of Ca(OH)2 with H3PO4. One set of reactions included poly acrylic acid in the reactant solution to modify the properties of the powder. Fibrinogen (Fg) Fraction I, type I: from Human plasma, (67% Protein), and Fibronectin (Fn) from Human plasma were selected to perform the adsorption experiments. The analysis of protein adsorption was carried out by UV/Vis spectrometry. A lower SSA and a different aspect ratio are obtained when the acrylic acid is included in the reaction badge. The deconvolution of the amide I band on the Raman spectra of free and adsorbed proteins reveals that the interaction apatite-protein happens through the carboxylate groups of the proteins. The combined analysis of CS, SSA and PS should be considered on the design of OHAp materials intended to interact with proteins. Copyright © 2013 Wiley Periodicals, Inc.

  3. Incorporating water-release and lateral protein interactions in modeling equilibrium adsorption for ion-exchange chromatography.

    Science.gov (United States)

    Thrash, Marvin E; Pinto, Neville G

    2006-09-08

    The equilibrium adsorption of two albumin proteins on a commercial ion exchanger has been studied using a colloidal model. The model accounts for electrostatic and van der Waals forces between proteins and the ion exchanger surface, the energy of interaction between adsorbed proteins, and the contribution of entropy from water-release accompanying protein adsorption. Protein-surface interactions were calculated using methods previously reported in the literature. Lateral interactions between adsorbed proteins were experimentally measured with microcalorimetry. Water-release was estimated by applying the preferential interaction approach to chromatographic retention data. The adsorption of ovalbumin and bovine serum albumin on an anion exchanger at solution pH>pI of protein was measured. The experimental isotherms have been modeled from the linear region to saturation, and the influence of three modulating alkali chlorides on capacity has been evaluated. The heat of adsorption is endothermic for all cases studied, despite the fact that the net charge on the protein is opposite that of the adsorbing surface. Strong repulsive forces between adsorbed proteins underlie the endothermic heat of adsorption, and these forces intensify with protein loading. It was found that the driving force for adsorption is the entropy increase due to the release of water from the protein and adsorbent surfaces. It is shown that the colloidal model predicts protein adsorption capacity in both the linear and non-linear isotherm regions, and can account for the effects of modulating salt.

  4. Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption.

    Science.gov (United States)

    Cai, Zhu-Yun; Peng, Fan; Zi, Yun-Peng; Chen, Feng; Qian, Qi-Rong

    2015-07-31

    Synthetic calcium phosphate (CaP)-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP) nanostructure was prepared under weak acidic conditions (pH 5), while the HAP nanorod was prepared under neutral (pH 7) and weak alkali (pH 9) condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb) as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption.

  5. Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption

    Directory of Open Access Journals (Sweden)

    Zhu-Yun Cai

    2015-07-01

    Full Text Available Synthetic calcium phosphate (CaP-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP nanostructure was prepared under weak acidic conditions (pH 5, while the HAP nanorod was prepared under neutral (pH 7 and weak alkali (pH 9 condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption.

  6. Tailored Poly(2-oxazoline) Polymer Brushes to Control Protein Adsorption and Cell Adhesion

    KAUST Repository

    Zhang, Ning; Pompe, Tilo; Amin, Ihsan; Luxenhofer, Robert; Werner, Carsten; Jordan, Rainer

    2012-01-01

    POx bottle-brush brushes (BBBs) are synthesized by SIPGP of 2-isopropenyl-2-oxazoline and consecutive LCROP of 2-oxazolines on 3-aminopropyltrimethoxysilane-modified silicon substrates. The side chain hydrophilicity and polarity are varied. The impact of the chemical composition and architecture of the BBB upon protein (fibronectin) adsorption and endothelial cell adhesion are investigated and prove extremely low protein adsorption and cell adhesion on BBBs with hydrophilic side chains such as poly(2-methyl-2-oxazoline) and poly(2-ethyl-2-oxazoline). The influence of the POx side chain terminal function upon adsorption and adhesion is minor but the side chain length has a significant effect on bioadsorption. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Tailored Poly(2-oxazoline) Polymer Brushes to Control Protein Adsorption and Cell Adhesion

    KAUST Repository

    Zhang, Ning

    2012-05-18

    POx bottle-brush brushes (BBBs) are synthesized by SIPGP of 2-isopropenyl-2-oxazoline and consecutive LCROP of 2-oxazolines on 3-aminopropyltrimethoxysilane-modified silicon substrates. The side chain hydrophilicity and polarity are varied. The impact of the chemical composition and architecture of the BBB upon protein (fibronectin) adsorption and endothelial cell adhesion are investigated and prove extremely low protein adsorption and cell adhesion on BBBs with hydrophilic side chains such as poly(2-methyl-2-oxazoline) and poly(2-ethyl-2-oxazoline). The influence of the POx side chain terminal function upon adsorption and adhesion is minor but the side chain length has a significant effect on bioadsorption. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Comb-like temperature-responsive polyhydroxyalkanoate-graft-poly(2-dimethylamino-ethylmethacrylate) for controllable protein adsorption

    DEFF Research Database (Denmark)

    Yao, Hui; Wei, Daixu; Che, Xuemei

    2016-01-01

    %. Graft copolymer PHA-g-PDMAEMA showed enhanced thermal stability, biocompatibility and controllable hydrophilicity compared with non-grafted P(3HDD-co-3H9D). The grafted material presented an obvious tendency of increasing protein adsorptions over the lower critical solution temperature (LCST 47.5 °C...... controllable protein adsorption for biomedical usages....

  9. Protein Exposed Hydrophobicity Reduces the Kinetic Barrier for Adsorption of Ovalbumin to the Air-Water Interface

    NARCIS (Netherlands)

    Wierenga, P.A.; Meinders, M.B.J.; Egmond, M.R.; Voragen, F.A.G.J.; Jongh, H.H.J. de

    2003-01-01

    Using native and caprylated ovalbumin, the role of exposed hydrophobicity on the kinetics of protein adsorption to the air - water interface is studied. First, changes in the chemical properties of the protein upon caprylation were characterized followed by measurement of the changes in adsorption

  10. Protein Adsorption and Its Role in Bacterial Film Development

    Science.gov (United States)

    1989-06-27

    only the secondary antibody conjugated to alkaline phosphatase was used. Combined Amino Acids as Measured by HPLC We are interested in a simple, direct...specific assay for chitin that relies on the lectin, wheat germ agglutinin (WGA). Lectins are a general class of proteins that bind to carbohydrates. The...protein; 2) a new method for measuring combined amino acids (includes proteins) in seawater was shown to measure higher concentration than the old

  11. Investigation of protein adsorption performance of Ni2+-attached diatomite particles embedded in composite monolithic cryogels.

    Science.gov (United States)

    Ünlü, Nuri; Ceylan, Şeyda; Erzengin, Mahmut; Odabaşı, Mehmet

    2011-08-01

    As a low-cost natural adsorbent, diatomite (DA) (2 μm) has several advantages including high surface area, chemical reactivity, hydrophilicity and lack of toxicity. In this study, the protein adsorption performance of supermacroporous composite cryogels embedded with Ni(2+)-attached DA particles (Ni(2+)-ADAPs) was investigated. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic composite cryogel column embedded with Ni(2+)-ADAPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N'-methylene-bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for affinity purification of human serum albumin (HSA) both from aqueous solutions and human serum. The chemical composition and surface area of DA was determined by XRF and BET method, respectively. The characterization of composite cryogel was investigated by SEM. The effect of pH, and embedded Ni(2+)-ADAPs amount, initial HSA concentration, temperature and flow rate on adsorption were studied. The maximum amount of HSA adsorption from aqueous solution at pH 8.0 phosphate buffer was very high (485.15 mg/g DA). It was observed that HSA could be repeatedly adsorbed and desorbed to the embedded Ni(2+)-ADAPs in poly(2-hydroxyethyl methacrylate) composite cryogel without significant loss of adsorption capacity. The efficiency of albumin adsorption from human serum before and after albumin adsorption was also investigated with SDS-PAGE analyses. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Polysaccharide charge density regulating protein adsorption to air/water interfaces by protein/polysaccharide complex formation

    NARCIS (Netherlands)

    Ganzevles, R.A.; Kosters, H.; Vliet, T. van; Stuart, M.A.C.; Jongh, H.H.J. de

    2007-01-01

    Because the formation of protein/polysaccharide complexes is dominated by electrostatic interaction, polysaccharide charge density is expected to play a major role in the adsorption behavior of the complexes. In this study, pullulan (a non-charged polysaccharide) carboxylated to four different

  13. Protein adsorption at air-water interfaces: A combination of details

    NARCIS (Netherlands)

    Jongh, de H.H.J.; Kosters, H.A.; Kudryashova, E.; Meinders, M.B.J.; Trofimova, D.; Wierenga, P.A.

    2004-01-01

    Using a variety of spectroscopic techniques, a number of molecular functionalities have been studied in relation to the adsorption process of proteins to air-water interfaces. While ellipsometry and drop tensiometry are used to derive information on adsorbed amount and exerted surface pressure,

  14. Self-consistent field theory of protein adsorption in a non-Gaussian polyelectrolyte brush

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Leermakers, F.A.M.; Stuart, M.A.C.

    2006-01-01

    To describe adsorption of globular protein molecules in a polyelectrolyte brush we use the strong-stretching approximation of the Edwards self-consistent field equation, combined with corrections for a non-Gaussian brush. To describe chemical potentials in this mixture of (globular) species of

  15. Protein Adsorption at Air-Water Interfaces: A Combination of Details

    NARCIS (Netherlands)

    Jongh, H.H.J.de; Kosters, H.A.; Kudryashova, E.; Meinders, M.B.J.; Trofimova, D.; Wierenga, P.A.

    2004-01-01

    Using a variety of spectroscopic techniques, a number of molecular functionalities have been studied in relation to the adsorption process of proteins to air-water interfaces. While ellipsometry and drop tensiometry are used to derive information on adsorbed amount and exerted surface pressure,

  16. Ice-surface adsorption enhanced colligative effect of antifreeze proteins in ice growth inhibition

    Science.gov (United States)

    Mao, Yougang; Ba, Yong

    2006-09-01

    This Communication describes a mechanism to explain antifreeze protein's function to inhibit the growth of ice crystals. We propose that the adsorption of antifreeze protein (AFP) molecules on an ice surface induces a dense AFP-water layer, which can significantly decrease the mole fraction of the interfacial water and, thus, lower the temperature for a seed ice crystal to grow in a super-cooled AFP solution. This mechanism can also explain the nearly unchanged melting point for the ice crystal due to the AFP's ice-surface adsorption. A mathematical model combining the Langmuir theory of adsorption and the colligative effect of thermodynamics has been proposed to find the equilibrium constants of the ice-surface adsorptions, and the interfacial concentrations of AFPs through fitting the theoretical curves to the experimental thermal hysteresis data. This model has been demonstrated by using the experimental data of serial size-mutated beetle Tenebrio molitor (Tm) AFPs. It was found that the AFP's ice-surface adsorptions could increase the interfacial AFP's concentrations by 3 to 4 orders compared with those in the bulk AFP solutions.

  17. Protein adsorption on tailored substrates: long-range forces and conformational changes

    Energy Technology Data Exchange (ETDEWEB)

    Bellion, M; Santen, L [Department of Theoretical Physics, Saarland University, 66041 Saarbruecken (Germany); Mantz, H; Haehl, H; Quinn, A; Nagel, A; Gilow, C; Weitenberg, C; Schmitt, Y; Jacobs, K [Department of Experimental Physics, Saarland University, 66041 Saarbruecken (Germany)], E-mail: k.jacobs@physik.uni-saarland.de

    2008-10-08

    Adsorption of proteins onto solid surfaces is an everyday phenomenon that is not yet fully understood. To further the current understanding, we have performed in situ ellipsometry studies to reveal the adsorption kinetics of three different proteins, lysozyme, {alpha}-amylase and bovine serum albumin. As substrates we offer Si wafers with a controlled Si oxide layer thickness and a hydrophilic or hydrophobic surface functionalization, allowing the tailoring of the influence of short- and long-range interactions. Our studies show that not only the surface chemistry determines the properties of an adsorbed protein layer but also the van der Waals contributions of a composite substrate. We compare the experimental findings to results of a colloidal Monte Carlo approach that includes conformational changes of the adsorbed proteins induced by density fluctuations.

  18. Synthesis of magnetite/graphene oxide/chitosan composite and its application for protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Nengsheng, E-mail: yensh@cnu.edu.cn; Xie, Yali; Shi, Pengzhi; Gao, Ting; Ma, Jichao

    2014-12-01

    In this study, a facile and novel strategy was developed to fabricate magnetite/graphene oxide/chitosan (Fe{sub 3}O{sub 4}/GO/CS) composite, and the composite was used as a magnetic adsorbent for the enrichment of protein, and followed by matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF MS) analysis. The phase composition, chemical structure and morphology of the composite were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), transmission electron microscopy (TEM), scanning electronic microscope (SEM) and vibrating sample magnetometer (VSM). Protein cytochrome c was chosen as model target to evaluate the adsorptive property of Fe{sub 3}O{sub 4}/GO/CS. After enrichment procedure and magnetic separation, protein bounded with the material was analyzed by MALDI-TOF MS without desorption. The results indicated that Fe{sub 3}O{sub 4}/GO/CS composite exhibited a good adsorptive capacity for protein, and Fe{sub 3}O{sub 4}/GO/CS composite had a promising potential in magnetic separation research. - Highlights: • Magnetite/graphene oxide/chitosan composite was synthesized by novel route. • The composite was used as magnetic absorbent for protein enrichment. • The composite had excellent adsorption performance for protein enrichment.

  19. Protein-adsorption and Ca-phosphate formation on chitosan-bioactive glass composite coatings

    Science.gov (United States)

    Wagener, V.; Boccaccini, A. R.; Virtanen, S.

    2017-09-01

    In the last years, chitosan-bioactive glass (BG) composites have been developed and investigated as bioactive coatings for orthopedic applications. The increase of bioactivity occurs due to the stimulation of calcium-phosphate/hydroxyapatite formation on the surface while the coating is degrading. In the present work, protein adsorption and its influence on calcium-phosphate precipitation was studied for the first time on such composite coatings. The experiments involved coating of 316L stainless steel substrates with chitosan (Ch) and chitosan-bioactive glass (Ch-BG) and immersion of the coated samples in two different bovine serum albumin (BSA) containing solutions, namely DI H2O (with pH adjusted to about 7.2 with diluted NaOH) and simulated body fluid (SBF). In order to investigate the influence of protein adsorption on calcium-phosphate precipitation, samples were also immersed in DI H2O and in SBF without BSA. Samples were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Surface analysis revealed that adsorption of BSA takes place on all studied samples and that protein adsorption is influenced by the presence of Ca2+ and PO43- ions. Bioactivity in the form of hydroxyapatite pre-stage formation is significantly increased on Ch-BG composite coating as compared with bare stainless steel surface. However, calcium-phosphate precipitation in SBF is reduced by the presence of BSA.

  20. Unified superresolution experiments and stochastic theory provide mechanistic insight into protein ion-exchange adsorptive separations.

    Science.gov (United States)

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Chen, Wen-Hsiang; Dhamane, Sagar; Willson, Richard C; Landes, Christy F

    2014-02-11

    Chromatographic protein separations, immunoassays, and biosensing all typically involve the adsorption of proteins to surfaces decorated with charged, hydrophobic, or affinity ligands. Despite increasingly widespread use throughout the pharmaceutical industry, mechanistic detail about the interactions of proteins with individual chromatographic adsorbent sites is available only via inference from ensemble measurements such as binding isotherms, calorimetry, and chromatography. In this work, we present the direct superresolution mapping and kinetic characterization of functional sites on ion-exchange ligands based on agarose, a support matrix routinely used in protein chromatography. By quantifying the interactions of single proteins with individual charged ligands, we demonstrate that clusters of charges are necessary to create detectable adsorption sites and that even chemically identical ligands create adsorption sites of varying kinetic properties that depend on steric availability at the interface. Additionally, we relate experimental results to the stochastic theory of chromatography. Simulated elution profiles calculated from the molecular-scale data suggest that, if it were possible to engineer uniform optimal interactions into ion-exchange systems, separation efficiencies could be improved by as much as a factor of five by deliberately exploiting clustered interactions that currently dominate the ion-exchange process only accidentally.

  1. In vitro investigation of protein adsorption and platelet adhesion on inorganic biomaterial surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Yan Huang [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096 (China); Lue Xiaoying [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096 (China)], E-mail: luxy@seu.edu.cn; Ma Jingwu [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096 (China); Nan Huang [Institute of Biomaterials and Surface Engineering, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: nhuang@263.com

    2008-11-15

    The aim of this paper was to study the surface properties, protein adsorption and platelet adhesion behaviors of diamond-like carbon (DLC) and titanium (Ti) films. The surface energy and microstructures of these films were characterized by contact angle measurement and atomic force microscopy (AFM). A modified Coomassie brilliant blue (CBB) protein assay was used to study the amount of adsorbed proteins. Platelet adhesion was assessed by scanning electron microscopy (SEM). The AFM results show that the DLC film is smoother than Ti. Protein adsorption results from CBB protein assay show that the ratio of adsorbed albumin (Alb) to IgG (R{sub A/I}) on DLC is larger than Ti, which coincide with the sequence of the ratio of interfacial tension between solid surface and Alb ({gamma}{sub S,Alb}) to interfacial tension between surface and IgG ({gamma}{sub S,IgG}) ({gamma}{sub S,Alb}/{gamma}{sub S,IgG}). The DLC film has a preferential adsorption for Alb. The results suggest that the ratio of {gamma}{sub S,Alb}/{gamma}{sub S,IgG} may indicate an Alb/IgG affinity ratio of materials. More platelets adhere on Ti film than on DLC, which may correspond to the surface roughness of materials. The conclusion is the blood compatibility of DLC seems to be better than Ti.

  2. Protein antigen adsorption to the DDA/TDB liposomal adjuvant

    DEFF Research Database (Denmark)

    Hamborg, Mette; Jorgensen, Lene; Bojsen, Anders Riber

    2013-01-01

    Understanding the nature of adjuvant-antigen interactions is important for the future design of efficient and safe subunit vaccines, but remains an analytical challenge. We studied the interactions between three model protein antigens and the clinically tested cationic liposomal adjuvant composed...... of dimethyldioctadecylammonium (DDA) and trehalose 6,6'-dibehenate (TDB)....

  3. Temperature and pH influence adsorption of cellobiohydrolase onto lignin by changing the protein properties.

    Science.gov (United States)

    Lu, Xianqin; Wang, Can; Li, Xuezhi; Zhao, Jian

    2017-12-01

    Non-productive adsorption of cellulase onto lignin restricted the movement of cellulase and also hindered the cellulase recycling in bioconversion of lignocellulose. In this study, effect of temperature and pH on adsorption and desorption of cellobiohydrolase (CBH) on lignin and its possible mechanism were discussed. It found that pH value and temperature influenced the adsorption and desorption behaviors of CBH on lignin. Different thermodynamic models suggested that the action between lignin and CBH was physical action. More CBH was adsorbed onto lignin, but lower initial adsorption velocity was detected at 50°C comparing with 4°C. Elevating pH value could improve desorption of cellulase from lignin. The changes of hydrophobicity and electric potential on protein surface may partially explain the impact of environmental conditions on the adsorption and desorption behaviors of CBH on lignin, and comparing to electrical interaction, the hydrophobicity may be the dominating factor influencing the behaviors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Effect of protein solution components in the adsorption of Herbaspirillum seropedicae GlnB protein on mica.

    Science.gov (United States)

    Ferreira, Cecília F G; Benelli, Elaine M; Klein, Jorge J; Schreiner, Wido; Camargo, Paulo C

    2009-10-15

    The adsorption of proteins and its buffer solution on mica surfaces was investigated by atomic force microscopy (AFM). Different salt concentration of the Herbaspirillum seropedicae GlnB protein (GlnB-Hs) solution deposited on mica was investigated. This protein is a globular, soluble homotrimer (36kDa), member of PII-like proteins family involved in signal transducing in prokaryote. Supramolecular structures were formed when this protein was deposited onto bare mica surface. The topographic AFM images of the GlnB-Hs films showed that at high salt concentration the supramolecular structures are spherical-like, instead of the typical doughnut-like shape for low salt concentration. AFM images of NaCl and Tris from the buffer solution showed structures with the same pattern as those observed for high salt protein solution, misleading the image interpretation. XPS experiments showed that GlnB protein film covers the mica surface without chemical reaction.

  5. Gold nanoparticles: role of size and surface chemistry on blood protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Benetti, F., E-mail: filippo.benetti@unitn.it; Fedel, M. [BIOtech Research Centre (Italy); Minati, L.; Speranza, G. [Fondazione Bruno Kessler (Italy); Migliaresi, C. [BIOtech Research Centre (Italy)

    2013-06-15

    Material interaction with blood proteins is a critical issue, since it could influence the biological processes taking place in the body following implantation/injection. This is particularly important in the case of nanoparticles, where innovative properties, such as size and high surface to volume ratio can lead to a behavioral change with respect to bulk macroscopic materials and could be responsible for a potential risk for human health. The aim of this work was to compare gold nanoparticles (AuNP) and planar surfaces to study the role of surface curvature moving from the macro- to the nano-size in the process of blood protein adsorption. In the course of the study, different protocols were tested to optimize the analysis of protein adsorption on gold nanoparticles. AuNP with different size (10, 60 and 200 nm diameter) and surface coatings (citrate and polyethylene glycol) were carefully characterized. The stabilizing action of blood proteins adsorbed on AuNP was studied measuring the variation of size and solubility of the nanoparticles following incubation with single protein solutions (human serum albumin and fibrinogen) and whole blood plasma. In addition, we developed a method to elute proteins from AuNP to study the propensity of gold materials to adsorb plasma proteins in function of dimensional characteristics and surface chemistry. We showed a different efficacy of the various eluting media tested, proving that even the most aggressive agent cannot provide a complete detachment of the protein corona. Enhanced protein adsorption was evidenced on AuNP if compared to gold laminae (bare and PEGylated) used as macroscopic control, probably due to the superior AuNP surface reactivity.

  6. Protein adsorption at the electrified air-water interface: implications on foam stability.

    Science.gov (United States)

    Engelhardt, Kathrin; Rumpel, Armin; Walter, Johannes; Dombrowski, Jannika; Kulozik, Ulrich; Braunschweig, Björn; Peukert, Wolfgang

    2012-05-22

    The surface chemistry of ions, water molecules, and proteins as well as their ability to form stable networks in foams can influence and control macroscopic properties such as taste and texture of dairy products considerably. Despite the significant relevance of protein adsorption at liquid interfaces, a molecular level understanding on the arrangement of proteins at interfaces and their interactions has been elusive. Therefore, we have addressed the adsorption of the model protein bovine serum albumin (BSA) at the air-water interface with vibrational sum-frequency generation (SFG) and ellipsometry. SFG provides specific information on the composition and average orientation of molecules at interfaces, while complementary information on the thickness of the adsorbed layer can be obtained with ellipsometry. Adsorption of charged BSA proteins at the water surface leads to an electrified interface, pH dependent charging, and electric field-induced polar ordering of interfacial H(2)O and BSA. Varying the bulk pH of protein solutions changes the intensities of the protein related vibrational bands substantially, while dramatic changes in vibrational bands of interfacial H(2)O are simultaneously observed. These observations have allowed us to determine the isoelectric point of BSA directly at the electrolyte-air interface for the first time. BSA covered air-water interfaces with a pH near the isoelectric point form an amorphous network of possibly agglomerated BSA proteins. Finally, we provide a direct correlation of the molecular structure of BSA interfaces with foam stability and new information on the link between microscopic properties of BSA at water surfaces and macroscopic properties such as the stability of protein foams.

  7. Load-dependent surface diffusion model for analyzing the kinetics of protein adsorption onto mesoporous materials.

    Science.gov (United States)

    Marbán, Gregorio; Ramírez-Montoya, Luis A; García, Héctor; Menéndez, J Ángel; Arenillas, Ana; Montes-Morán, Miguel A

    2018-02-01

    The adsorption of cytochrome c in water onto organic and carbon xerogels with narrow pore size distributions has been studied by carrying out transient and equilibrium batch adsorption experiments. It was found that equilibrium adsorption exhibits a quasi-Langmuirian behavior (a g coefficient in the Redlich-Peterson isotherms of over 0.95) involving the formation of a monolayer of cyt c with a depth of ∼4nm on the surface of all xerogels for a packing density of the protein inside the pores of 0.29gcm -3 . A load-dependent surface diffusion model (LDSDM) has been developed and numerically solved to fit the experimental kinetic adsorption curves. The results of the LDSDM show better fittings than the standard homogeneous surface diffusion model. The value of the external mass transfer coefficient obtained by numerical optimization confirms that the process is controlled by the intraparticle surface diffusion of cyt c. The surface diffusion coefficients decrease with increasing protein load down to zero for the maximum possible load. The decrease is steeper in the case of the xerogels with the smallest average pore diameter (∼15nm), the limit at which the zero-load diffusion coefficient of cyt c also begins to be negatively affected by interactions with the opposite wall of the pore. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Characterization of dextran-grafted hydrophobic charge-induction resins: Structural properties, protein adsorption and transport.

    Science.gov (United States)

    Liu, Tao; Angelo, James M; Lin, Dong-Qiang; Lenhoff, Abraham M; Yao, Shan-Jing

    2017-09-29

    The structural and functional properties of a series of dextran-grafted and non-grafted hydrophobic charge-induction chromatographic (HCIC) agarose resins were characterized by macroscopic and microscopic techniques. The effects of dextran grafting and mobile phase conditions on the pore dimensions of the resins were investigated with inverse size exclusion chromatography (ISEC). A significantly lower pore radius (17.6nm) was found for dextran-grafted than non-grafted resins (29.5nm), but increased salt concentration would narrow the gap between the respective pore radii. Two proteins, human immunoglobulin G (hIgG) and bovine serum albumin (BSA), were used to examine the effect of protein characteristics. The results of adsorption isotherms showed that the dextran-grafted resin with high ligand density had substantially higher adsorption capacity and enhanced the salt-tolerance property for hIgG, but displayed a significantly smaller benefit for BSA adsorption. Confocal laser scanning microscopy (CLSM) showed that hIgG presented more diffuse and slower moving adsorption front compared to BSA during uptake into the resins because of the selective binding of multiple species from polyclonal IgG; polymer-grafting with high ligand density could enhance the rate of hIgG transport in the dextran-grafted resins without salt addition, but not for the case with high salt and BSA. The results indicate that microscopic analysis using ISEC and CLSM is useful to improve the mechanistic understanding of resin structure and of critical functional parameters involving protein adsorption and transport, which would guide the rational design of new resins and processes. Copyright © 2017. Published by Elsevier B.V.

  9. Protein Adsorption Patterns and Analysis on IV Nanoemulsions—The Key Factor Determining the Organ Distribution

    Directory of Open Access Journals (Sweden)

    Mirko Jansch

    2012-12-01

    Full Text Available Intravenous nanoemulsions have been on the market for parenteral nutrition since the 1950s; meanwhile, they have also been used successfully for IV drug delivery. To be well tolerable, the emulsions should avoid uptake by the MPS cells of the body; for drug delivery, they should be target-specific. The organ distribution is determined by the proteins adsorbing them after injection from the blood (protein adsorption pattern, typically analyzed by two-dimensional polyacrylamide gel electrophoresis, 2-D PAGE. The article reviews the 2-D PAGE method, the analytical problems to be faced and the knowledge available on how the composition of emulsions affects the protein adsorption patterns, e.g., the composition of the oil phase, stabilizer layer and drug incorporation into the interface or oil core. Data were re-evaluated and compared, and the implications for the in vivo distribution are discussed. Major results are that the interfacial composition of the stabilizer layer is the main determining factor and that this composition can be modulated by simple processes. Drug incorporation affects the pattern depending on the localization of the drug (oil core versus interface. The data situation regarding in vivo effects is very limited; mainly, it has to be referred to in the in vivo data of polymeric nanoparticles. As a conclusion, determination of the protein adsorption patterns can accelerate IV nanoemulsion formulation development regarding optimized organ distribution and related pharmacokinetics.

  10. Protein Adsorption Patterns and Analysis on IV Nanoemulsions-The Key Factor Determining the Organ Distribution.

    Science.gov (United States)

    Keck, Cornelia M; Jansch, Mirko; Müller, Rainer H

    2012-12-21

    Intravenous nanoemulsions have been on the market for parenteral nutrition since the 1950s; meanwhile, they have also been used successfully for IV drug delivery. To be well tolerable, the emulsions should avoid uptake by the MPS cells of the body; for drug delivery, they should be target-specific. The organ distribution is determined by the proteins adsorbing them after injection from the blood (protein adsorption pattern), typically analyzed by two-dimensional polyacrylamide gel electrophoresis, 2-D PAGE. The article reviews the 2-D PAGE method, the analytical problems to be faced and the knowledge available on how the composition of emulsions affects the protein adsorption patterns, e.g., the composition of the oil phase, stabilizer layer and drug incorporation into the interface or oil core. Data were re-evaluated and compared, and the implications for the in vivo distribution are discussed. Major results are that the interfacial composition of the stabilizer layer is the main determining factor and that this composition can be modulated by simple processes. Drug incorporation affects the pattern depending on the localization of the drug (oil core versus interface). The data situation regarding in vivo effects is very limited; mainly, it has to be referred to in the in vivo data of polymeric nanoparticles. As a conclusion, determination of the protein adsorption patterns can accelerate IV nanoemulsion formulation development regarding optimized organ distribution and related pharmacokinetics.

  11. Atomistic simulation of the coupled adsorption and unfolding of protein GB1 on the polystyrenes nanoparticle surface

    Science.gov (United States)

    Xiao, HuiFang; Huang, Bin; Yao, Ge; Kang, WenBin; Gong, Sheng; Pan, Hai; Cao, Yi; Wang, Jun; Zhang, Jian; Wang, Wei

    2018-03-01

    Understanding the processes of protein adsorption/desorption on nanoparticles' surfaces is important for the development of new nanotechnology involving biomaterials; however, an atomistic resolution picture for these processes and for the simultaneous protein conformational change is missing. Here, we report the adsorption of protein GB1 on a polystyrene nanoparticle surface using atomistic molecular dynamic simulations. Enabled by metadynamics, we explored the relevant phase space and identified three protein states, each involving both the adsorbed and desorbed modes. We also studied the change of the secondary and tertiary structures of GB1 during adsorption and the dominant interactions between the protein and surface in different adsorption stages. The results we obtained from simulation were found to be more adequate and complete than the previous one. We believe the model presented in this paper, in comparison with the previous ones, is a better theoretical model to understand and explain the experimental results.

  12. Poly(l-glutamic acid)-g-poly(ethylene glycol) external layer in polyelectrolyte multilayer films: Characterization and resistance to serum protein adsorption.

    Science.gov (United States)

    Szczepanowicz, Krzysztof; Kruk, Tomasz; Świątek, Wiktoria; Bouzga, Aud M; Simon, Christian R; Warszyński, Piotr

    2018-06-01

    Formation of protein-resistant surfaces is a major challenge in the design of novel biomaterials and an important strategy to prevent protein adsorption is the formation of protein-resistant coatings. It can be achieved by proper modification of surfaces, e.g., by immobilization of hydrophilic polymers such as poly(ethylene glycol) (PEG). An appropriate method to immobilize PEG at charged surfaces is the adsorption of copolymers with PEG chains grafted onto polyelectrolyte backbone. The growing interest in the use of polyelectrolyte multilayer coatings in biomedical applications to improve biocompatibility and/or to prepare coating with antiadhesive properties has been the main reason for these studies. Therefore the aim was to produce protein resistant polyelectrolyte multilayer films. They were formed via the layer-by-layer approach, while their pegylation by the deposition of pegylated polyanion, PGA-g-PEG, as an external layer. The influence of PEG chain length and grafting density of PGA-g-PEG copolymers on the protein antiadhesive properties of pegylated polyelectrolyte multilayer films was investigated. To monitor the formation of pegylated and non-pegylated multilayer films, adsorption of the following proteins: HSA, Fibrinogen, and FBS were measured by quartz crystal microbalance (QCM - D). We found that protein adsorption onto all pegylated polyelectrolyte multilayers was significantly reduced in comparison to non-pegylated ones. Long-term performance tests confirmed the stability and the durability of the protein resistant properties of the pegylated multilayers. Antiadhesive properties of tested surfaces pegylated by PGA-g-PEG were compared to the available data for pegylated polycation PLL-g-PEG. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. A colloidal assembly approach to synthesize magnetic porous composite nanoclusters for efficient protein adsorption

    Science.gov (United States)

    Yang, Qi; Lan, Fang; Yi, Qiangying; Wu, Yao; Gu, Zhongwei

    2015-10-01

    A combination strategy of the inverse emulsion crosslinking approach and the colloidal assembly technique is first proposed to synthesize Fe3O4/histidine composite nanoclusters as new-type magnetic porous nanomaterials. The nanoclusters possess uniform morphology, high magnetic content and excellent protein adsorption capacity, exhibiting their great potential for bio-separation.A combination strategy of the inverse emulsion crosslinking approach and the colloidal assembly technique is first proposed to synthesize Fe3O4/histidine composite nanoclusters as new-type magnetic porous nanomaterials. The nanoclusters possess uniform morphology, high magnetic content and excellent protein adsorption capacity, exhibiting their great potential for bio-separation. Electronic supplementary information (ESI) available: Experimental details. See DOI: 10.1039/c5nr05800g

  14. Effect of thermal stability on protein adsorption to silica using homologous aldo-keto reductases

    OpenAIRE

    Felsovalyi, Flora; Patel, Tushar; Mangiagalli, Paolo; Kumar, Sanat K; Banta, Scott

    2012-01-01

    Gaining more insight into the mechanisms governing the behavior of proteins at solid/liquid interfaces is particularly relevant in the interaction of high-value biologics with storage and delivery device surfaces, where adsorption-induced conformational changes may dramatically affect biocompatibility. The impact of structural stability on interfacial behavior has been previously investigated by engineering nonwild-type stability mutants. Potential shortcomings of such approaches include only...

  15. Effect of DOPE and cholesterol on the protein adsorption onto lipid nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Caracciolo, Giulio, E-mail: giulio.caracciolo@uniroma1.it; Pozzi, Daniela [' Sapienza' University of Rome, Department of Molecular Medicine (Italy); Capriotti, Anna Laura; Cavaliere, Chiara; Lagana, Aldo [' Sapienza' University of Rome, Department of Chemistry (Italy)

    2013-03-15

    Upon administration, nanoparticles (NPs) are exposed to biological fluids from which they adsorb proteins and other biomolecules to form a 'protein corona'. NP-protein interactions are still poorly understood and quantitative studies to characterize them remain scarce. Here, we have investigated the effect of neutral dioleoylphosphatidylethanolamine (DOPE) and cholesterol on the adsorption of human plasma proteins onto the surface of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-based cationic liposomes of 100 nm in diameter. Quantitative analysis of the protein corona revealed that replacing cationic DOTAP lipids with neutral lipids, being indifferently DOPE or cholesterol, reduces the affinity of fibrinogen, prothrombin, vitamin K, and vitronectin for the lipid surface. On the other side, DOPE specifically promotes the adsorption of apolipoproteins and serum albumin, while cholesterol induces the preferential binding of immunoglobulins and complement proteins. The results of this study will help to explain why NPs of different lipid compositions have a dramatic difference in their in vivo transfection efficiency and will be useful for design of lipid NPs with optimal circulation profiles.

  16. Effect of DOPE and cholesterol on the protein adsorption onto lipid nanoparticles

    International Nuclear Information System (INIS)

    Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; Cavaliere, Chiara; Laganà, Aldo

    2013-01-01

    Upon administration, nanoparticles (NPs) are exposed to biological fluids from which they adsorb proteins and other biomolecules to form a “protein corona”. NP–protein interactions are still poorly understood and quantitative studies to characterize them remain scarce. Here, we have investigated the effect of neutral dioleoylphosphatidylethanolamine (DOPE) and cholesterol on the adsorption of human plasma proteins onto the surface of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-based cationic liposomes of 100 nm in diameter. Quantitative analysis of the protein corona revealed that replacing cationic DOTAP lipids with neutral lipids, being indifferently DOPE or cholesterol, reduces the affinity of fibrinogen, prothrombin, vitamin K, and vitronectin for the lipid surface. On the other side, DOPE specifically promotes the adsorption of apolipoproteins and serum albumin, while cholesterol induces the preferential binding of immunoglobulins and complement proteins. The results of this study will help to explain why NPs of different lipid compositions have a dramatic difference in their in vivo transfection efficiency and will be useful for design of lipid NPs with optimal circulation profiles.

  17. Persistence of detectable insecticidal proteins from Bacillus thuringiensis (Cry) and toxicity after adsorption on contrasting soils

    International Nuclear Information System (INIS)

    Hung, T.P.; Truong, L.V.; Binh, N.D.; Frutos, R.; Quiquampoix, H.; Staunton, S.

    2016-01-01

    Insecticidal Cry, or Bt, proteins are produced by the soil-endemic bacterium, Bacillus thuringiensis and some genetically modified crops. Their environmental fate depends on interactions with soil. Little is known about the toxicity of adsorbed proteins and the change in toxicity over time. We incubated Cry1Ac and Cry2A in contrasting soils subjected to different treatments to inhibit microbial activity. The toxin was chemically extracted and immunoassayed. Manduca sexta was the target insect for biotests. Extractable toxin decreased during incubation for up to four weeks. Toxicity of Cry1Ac was maintained in the adsorbed state, but lost after 2 weeks incubation at 25 °C. The decline in extractable protein and toxicity were much slower at 4 °C with no significant effect of soil sterilization. The major driving force for decline may be time-dependent fixation of adsorbed protein, leading to a decrease in the extraction yield in vitro, paralleled by decreasing solubilisation in the larval gut. - Graphical abstract: Biotest, presenting Cry-contaminated feed to Manduca sexta larvae in individual Perspex boxes. Display Omitted - Highlights: • Toxicity of Cry protein is initially conserved after adsorption on soil. • Toxicity and extractability decline with time, more rapidly at 25 °C than 4 °C. • Similar dynamics of Cry1AC and Cry2A on soil with varying texture and organic C. • Sterilization of soil does not change Cry dynamics or temperature effect in soil. • Cry decline is determined by progressive fixation on soil not microbial breakdown. - Toxicity was initially maintained after adsorption on soil and both extractable Cry and toxicity declined rapidly, more slowly at low temperature, due to different fixation dynamics. Toxicity of Cry protein is initially conserved after adsorption on soil.

  18. Dissociation coefficients of protein adsorption to nanoparticles as quantitative metrics for description of the protein corona: A comparison of experimental techniques and methodological relevance

    KAUST Repository

    Hü hn, Jonas; Fedeli, Chiara; Zhang, Qian; Masood, Atif; del Pino, Pablo; Khashab, Niveen M.; Papini, Emanuele; Parak, Wolfgang J.

    2015-01-01

    Protein adsorption to nanoparticles is described as a chemical reaction in which proteins attach to binding sites on the nanoparticle surface. This process can be described with a dissociation coefficient, which tells how many proteins are adsorbed per nanoparticle in dependence of the protein concentration. Different techniques to experimentally determine dissociation coefficients of protein adsorption to nanoparticles are reviewed. Results of more than 130 experiments in which dissociation coefficients have been determined are compared. Data show that different methods, nanoparticle systems, and proteins can lead to significantly different dissociation coefficients. However, we observed a clear tendency of smaller dissociation coefficients upon less negative towards more positive zeta potentials of the nanoparticles. The zeta potential thus is a key parameter influencing protein adsorption to the surface of nanoparticles. Our analysis highlights the importance of the characterization of the parameters governing protein-nanoparticle interaction for quantitative evaluation and objective literature comparison.

  19. Dissociation coefficients of protein adsorption to nanoparticles as quantitative metrics for description of the protein corona: A comparison of experimental techniques and methodological relevance

    KAUST Repository

    Hühn, Jonas

    2015-12-31

    Protein adsorption to nanoparticles is described as a chemical reaction in which proteins attach to binding sites on the nanoparticle surface. This process can be described with a dissociation coefficient, which tells how many proteins are adsorbed per nanoparticle in dependence of the protein concentration. Different techniques to experimentally determine dissociation coefficients of protein adsorption to nanoparticles are reviewed. Results of more than 130 experiments in which dissociation coefficients have been determined are compared. Data show that different methods, nanoparticle systems, and proteins can lead to significantly different dissociation coefficients. However, we observed a clear tendency of smaller dissociation coefficients upon less negative towards more positive zeta potentials of the nanoparticles. The zeta potential thus is a key parameter influencing protein adsorption to the surface of nanoparticles. Our analysis highlights the importance of the characterization of the parameters governing protein-nanoparticle interaction for quantitative evaluation and objective literature comparison.

  20. Microbiome Remodeling via the Montmorillonite Adsorption-Excretion Axis Prevents Obesity-related Metabolic Disorders

    Directory of Open Access Journals (Sweden)

    Pengfei Xu

    2017-02-01

    Full Text Available Obesity and its related metabolic disorders are closely correlated with gut dysbiosis. Montmorillonite is a common medicine used to treat diarrhea. We have previously found that dietary lipid adsorbent-montmorillonite (DLA-M has an unexpected role in preventing obesity. The aim of this study was to further investigate whether DLA-M regulates intestinal absorption and gut microbiota to prevent obesity-related metabolic disorders. Here, we show that DLA-M absorbs free fatty acids (FFA and endotoxins in vitro and in vivo. Moreover, the combination of fluorescent tracer technique and polarized light microscopy showed that DLA-M crystals immobilized BODIPY® FL C16 and FITC-LPS, respectively, in the digestive tract in situ. HFD-fed mice treated with DLA-M showed mild changes in the composition of the gut microbiota, particularly increases in short-chain fatty acids (SCFA-producing Blautia bacteria and decreases in endotoxin-producing Desulfovibrio bacteria, these changes were positively correlated with obesity and inflammation. Our results indicated that DLA-M immobilizes FFA and endotoxins in the digestive tract via the adsorption-excretion axis and DLA-M may potentially be used as a prebiotic to prevent intestinal dysbiosis and obesity-associated metabolic disorders in obese individuals.

  1. Adsorption of Hydrophobin-Protein Mixtures at the Air-Water Interface: The Impact of pH and Electrolyte.

    Science.gov (United States)

    Tucker, Ian M; Petkov, Jordan T; Penfold, Jeffrey; Thomas, Robert K; Cox, Andrew R; Hedges, Nick

    2015-09-15

    The adsorption of the proteins β-casein, β-lactoglobulin, and hydrophobin, and the protein mixtures of β-casein/hydrophobin and β-lactoglobulin/hydrophobin have been studied at the air-water interface by neutron reflectivity, NR. Changing the solution pH from 7 to 2.6 has relatively little impact on the adsorption of hydrophobin or β-lactoglobulin, but results in a substantial change in the structure of the adsorbed layer of β-casein. In β-lactoglobulin/hydrophobin mixtures, the adsorption is dominated by the hydrophobin adsorption, and is independent of the hydrophobin or β-lactoglobulin concentration and solution pH. At pH 2.6, the adsorption of the β-casein/hydrophobin mixtures is dominated by the hydrophobin adsorption over the range of β-casein concentrations studied. At pH 4 and 7, the adsorption of β-casein/hydrophobin mixtures is dominated by the hydrophobin adsorption at low β-casein concentrations. At higher β-casein concentrations, β-casein is adsorbed onto the surface monolayer of hydrophobin, and some interpenetration between the two proteins occurs. These results illustrate the importance of pH on the intermolecular interactions between the two proteins at the interface. This is further confirmed by the impact of PBS, phosphate buffered saline, buffer and CaCl2 on the coadsorption and surface structure. The results provide an important insight into the adsorption properties of protein mixtures and their application in foam and emulsion stabilization.

  2. Protein adsorption at polymer-grafted surfaces: Comparison between a mixture of saliva proteins and some well-defined model proteins

    NARCIS (Netherlands)

    Kawasaki, K.; Kambara, M.; Matsumura, H.; Norde, W.

    2003-01-01

    Grafting a dense layer of soluble polymers onto a surface is a well-established method for controlling protein adsorption. In the present study, polyethylene oxide (PEO) layers of three different grafting densities were prepared, i.e. 10-15 nm2, 5.5 nm2 and 4 nm2 per polymer chain, respectively. The

  3. Characterization of protein adsorption onto FePt nanoparticles using dual-focus fluorescence correlation spectroscopy

    Directory of Open Access Journals (Sweden)

    Pauline Maffre

    2011-07-01

    Full Text Available Using dual-focus fluorescence correlation spectroscopy, we have analyzed the adsorption of three human blood serum proteins, namely serum albumin, apolipoprotein A-I and apolipoprotein E4, onto polymer-coated, fluorescently labeled FePt nanoparticles (~12 nm diameter carrying negatively charged carboxyl groups on their surface. For all three proteins, a step-wise increase in hydrodynamic radius with protein concentration was observed, strongly suggesting the formation of protein monolayers that enclose the nanoparticles. Consistent with this interpretation, the absolute increase in hydrodynamic radius can be correlated with the molecular shapes of the proteins known from X-ray crystallography and solution experiments, indicating that the proteins bind on the nanoparticles in specific orientations. The equilibrium dissociation coefficients, measuring the affinity of the proteins to the nanoparticles, were observed to differ by almost four orders of magnitude. These variations can be understood in terms of the electrostatic properties of the proteins. From structure-based calculations of the surface potentials, positively charged patches of different extents can be revealed, through which the proteins interact electrostatically with the negatively charged nanoparticle surfaces.

  4. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Huihui; Qian, Bin; Zhang, Wei [Shanghai Key Laboratory of Functional Materials Chemistry and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); Lan, Minbo, E-mail: minbolan@ecust.edu.cn [Shanghai Key Laboratory of Functional Materials Chemistry and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-02-15

    Highlights: • Antifouling PVP brushes were successfully grafted on PU films by SI-ATRP. • The effect of polymerization time on surface property and topography was studied. • Hydrophilicity and protein fouling resistance of PVP–PU films were greatly promoted. • Competitive adsorption of three proteins on PVP–PU films was evaluated. - Abstract: An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU–PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU–PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU–PVP (6.0 h) film reduced greatly to 0.08 μg/cm{sup 2}, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  5. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    International Nuclear Information System (INIS)

    Yuan, Huihui; Qian, Bin; Zhang, Wei; Lan, Minbo

    2016-01-01

    Highlights: • Antifouling PVP brushes were successfully grafted on PU films by SI-ATRP. • The effect of polymerization time on surface property and topography was studied. • Hydrophilicity and protein fouling resistance of PVP–PU films were greatly promoted. • Competitive adsorption of three proteins on PVP–PU films was evaluated. - Abstract: An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU–PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU–PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU–PVP (6.0 h) film reduced greatly to 0.08 μg/cm"2, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  6. Platelet adhesion and plasma protein adsorption control of collagen surfaces by He+ ion implantation

    International Nuclear Information System (INIS)

    Kurotobi, K.; Suzuki, Y.; Nakajima, H.; Suzuki, H.; Iwaki, M.

    2003-01-01

    He + ion implanted collagen-coated tubes with a fluence of 1 x 10 14 ions/cm 2 were exhibited antithrombogenicity. To investigate the mechanisms of antithrombogenicity of these samples, plasma protein adsorption assay and platelet adhesion experiments were performed. The adsorption of fibrinogen (Fg) and von Willebrand factor (vWf) was minimum on the He + ion implanted collagen with a fluence of 1 x 10 14 ions/cm 2 . Platelet adhesion (using platelet rich plasma) was inhibited on the He + ion implanted collagen with a fluence of 1 x 10 14 ions/cm 2 and was accelerated on the untreated collagen and ion implanted collagen with fluences of 1 x 10 13 , 1 x 10 15 and 1 x 10 16 ions/cm 2 . Platelet activation with washed platelets was observed on untreated collagen and He + ion implanted collagen with a fluence of 1 x 10 14 ions/cm 2 and was inhibited with fluences of 1 x 10 13 , 1 x 10 15 and 1 x 10 16 ions/cm 2 . Generally, platelets can react with a specific ligand inside the collagen (GFOGER sequence). The results of platelets adhesion experiments using washed platelets indicated that there were no ligands such as GFOGER on the He + ion implanted collagen over a fluence of 1 x 10 13 ions/cm 2 . On the 1 x 10 14 ions/cm 2 implanted collagen, no platelet activation was observed due to the influence of plasma proteins. >From the above, it is concluded that the decrease of adsorbed Fg and vWf caused the antithrombogenicity of He + ion implanted collagen with a fluence of 1 x 10 14 ions/cm 2 and that plasma protein adsorption took an important role repairing the graft surface

  7. Self-colored nanoparticles containing naphthalene-bisimide derivatives: Synthesis and protein adsorption study

    Energy Technology Data Exchange (ETDEWEB)

    Polpanich, Duangporn, E-mail: duangporn@nanotec.or.th [National Nanotechnology Center, National Science and Technology Development Agency, Thailand Science Park, Pathumthani 12120 (Thailand); Asawapirom, Udom; Thiramanas, Raweewan; Piyakulawat, Phimwipha [National Nanotechnology Center, National Science and Technology Development Agency, Thailand Science Park, Pathumthani 12120 (Thailand)

    2011-09-15

    Highlights: {yields} Novel polymerizable naphthalene-bisimide dyes were designed and synthesized. {yields} Highly monodispersed self-colored nanoparticles were successfully prepared. {yields} Good colloidal stability of the nanoparticles was achieved after protein adsorption. - Abstract: An approach to covalently bound the novel polymerizable dyes, 2,3,6,7-tetrathienyl-1,4,5,8-naphthalenetetracarboxylic-N,N' -di(2-methylallyl)-bisimide (ALN4T) and 2,3,6,7-tetra(2,2'-bithiophene)-1,4,5,8-naphthalenetetracarboxylic-N,N' -di(2-methylallyl)-bisimide (ALN8T), and vinyl monomers for tailoring the self-colored nanoparticles (NPs) was demonstrated. Using the miniemulsion polymerization technique, the NPs with high conversion were synthesized. Examining the particles by scanning electron micrograph (SEM) revealed a uniform size distribution. UV/vis spectroscopy results showed that the colored NPs comprising of ALN4T exhibited the same absorption maxima compared to that of the parent dye, while a hypsochromic shift was observed when using ALN8T. By using bovine serum albumin (BSA) as a model, the amount of protein adsorption ({Gamma}{sub ads}) onto the surface of the colored NPs was evaluated. The {Gamma}{sub ads} on the colored NPs was found to be dictated by synergistic effects of the conformation change of BSA at a given pH and the electrostatic interaction between the protein and the particle surface. The good colloidal stability of the NPs after BSA adsorption was observed by zeta potential measurement. Therefore, the prepared self-colored NPs have potential application in biomedical areas.

  8. Particle size effects on protein and virus-like particle adsorption on perfusion chromatography media.

    Science.gov (United States)

    Wu, Yige; Abraham, Dicky; Carta, Giorgio

    2015-01-02

    The resin structure, chromatographic behavior, and adsorption kinetics of proteins and virus-like-particles (VLPs) are studied for POROS HS 20 and POROS HS 50 (23 and 52 μm mean diameter, respectively) to determine the effects of particle size on perfusion chromatography and to determine the predictive ability of available models. Transmission electron microscopy (TEM) and inverse size-exclusion chromatography (iSEC) show similar structures for the two resins, both containing 200-1000 nm pores that transect a network of much smaller pores. For non-binding conditions, trends of the height equivalent to a theoretical plate (HETP) as a function of reduced velocity are consistent with perfusion. The estimated intraparticle flow fractions for these conditions are 0.0018 and 0.00063 for POROS HS 20 and HS 50, respectively. For strong binding conditions, confocal laser scanning microscopy (CLSM) shows asymmetrical intraparticle concentrations profiles and enhanced rates of IgG adsorption on POROS HS 20 at 1000 cm/h. The corresponding effective diffusivity under flow is 2-3 times larger than for non-flow conditions and much larger than observed for POROS HS 50, consistent with available models. For VLPs, however, adsorption is confined to a thin layer near the particle surface for both resins, suggesting that the bound VLPs block the pores. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Dynamic Contact Angle Analysis of Protein Adsorption on Polysaccharide Multilayer’s Films for Biomaterial Reendothelialization

    Directory of Open Access Journals (Sweden)

    Safiya Benni

    2014-01-01

    Full Text Available Atherosclerosis is a major cardiovascular disease. One of the side effects is restenosis. The aim of this work was to study the coating of stents by dextran derivates based polyelectrolyte’s multilayer (PEM films in order to increase endothelialization of injured arterial wall after stent implantation. Films were composed with diethylaminoethyl dextran (DEAE as polycation and dextran sulphate (DS as polyanion. One film was composed with 4 bilayers of (DEAE-DS4 and was labeled D−. The other film was the same as D− but with an added terminal layer of DEAE polycation: (DEAE-DS4-DEAE (labeled D+. The dynamic adsorption/desorption of proteins on the films were characterized by dynamic contact angle (DCA and atomic force microscopy (AFM. Human endothelial cell (HUVEC adhesion and proliferation were quantified and correlated to protein adsorption analyzed by DCA for fibronectin, vitronectin, and bovine serum albumin (BSA. Our results showed that the endothelial cell response was optimal for films composed of DS as external layer. Fibronectin was found to be the only protein to exhibit a reversible change in conformation after desorption test. This behavior was only observed for (DEAE-DS4 films. (DEAE-DS4 films could enhance HUVEC proliferation in agreement with fibronectin ability to easily change from conformation.

  10. Protein Adsorption onto Nanomaterials for the Development of Biosensors and Analytical Devices: A Review

    Science.gov (United States)

    Bhakta, Samir A.; Evans, Elizabeth; Benavidez, Tomás E.; Garcia, Carlos D.

    2014-01-01

    An important consideration for the development of biosensors is the adsorption of the bio recognition element to the surface of a substrate. As the first step in the immobilization process, adsorption affects most immobilization routes and much attention is given into the research of this process to maximize the overall activity of the bio sensor. The use of nanomaterials, specifically nanoparticles and nanostructured films, offers advantageous properties that can be fine-tuned for interaction with specific proteins to maximize activity, minimize structural changes, and enhance the catalytic step. In the biosensor field, protein-nanomaterial interactions are an emerging trend that span across many disciplines. This review addresses recent publications about the proteins most frequently used, their most relevant characteristics, and the conditions required to adsorb them to nanomaterials. When relevant and available, subsequent analytical figures of merits are discussed for selected biosensors. The general trend amongst the research papers allows concluding that the use of nanomaterials has already provided significant improvements in the analytical performance of many biosensors and that this research field will continue to grow. PMID:25892065

  11. Enhanced protein adsorption and patterning on nanostructured latex-coated paper.

    Science.gov (United States)

    Juvonen, Helka; Määttänen, Anni; Ihalainen, Petri; Viitala, Tapani; Sarfraz, Jawad; Peltonen, Jouko

    2014-06-01

    Specific interactions of extracellular matrix proteins with cells and their adhesion to the substrate are important for cell growth. A nanopatterned latex-coated paper substrate previously shown to be an excellent substrate for cell adhesion and 2D growth was studied for directed immobilization of proteins. The nanostructured latex surface was formed by short-wavelength IR irradiation of a two-component latex coating consisting of a hydrophilic film-forming styrene butadiene acrylonitrile copolymer and hydrophobic polystyrene particles. The hydrophobic regions of the IR-treated latex coating showed strong adhesion of bovine serum albumin (cell repelling protein), fibronectin (cell adhesive protein) and streptavidin. Opposite to the IR-treated surface, fibronectin and streptavidin had a poor affinity toward the untreated pristine latex coating. Detailed characterization of the physicochemical surface properties of the latex-coated substrates revealed that the observed differences in protein affinity were mainly due to the presence or absence of the protein repelling polar and charged surface groups. The protein adsorption was assisted by hydrophobic (dehydration) interactions. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Controlled surface chemistry of diamond/β-SiC composite films for preferential protein adsorption.

    Science.gov (United States)

    Wang, Tao; Handschuh-Wang, Stephan; Yang, Yang; Zhuang, Hao; Schlemper, Christoph; Wesner, Daniel; Schönherr, Holger; Zhang, Wenjun; Jiang, Xin

    2014-02-04

    Diamond and SiC both process extraordinary biocompatible, electronic, and chemical properties. A combination of diamond and SiC may lead to highly stable materials, e.g., for implants or biosensors with excellent sensing properties. Here we report on the controllable surface chemistry of diamond/β-SiC composite films and its effect on protein adsorption. For systematic and high-throughput investigations, novel diamond/β-SiC composite films with gradient composition have been synthesized using the hot filament chemical vapor deposition (HFCVD) technique. As revealed by scanning electron microscopy (SEM), the diamond/β-SiC ratio of the composite films shows a continuous change from pure diamond to β-SiC over a length of ∼ 10 mm on the surface. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to unveil the surface termination of chemically oxidized and hydrogen treated surfaces. The surface chemistry of the composite films was found to depend on diamond/β-SiC ratio and the surface treatment. As observed by confocal fluorescence microscopy, albumin and fibrinogen were preferentially adsorbed from buffer: after surface oxidation, the proteins preferred to adsorb on diamond rather than on β-SiC, resulting in an increasing amount of proteins adsorbed to the gradient surfaces with increasing diamond/β-SiC ratio. By contrast, for hydrogen-treated surfaces, the proteins preferentially adsorbed on β-SiC, leading to a decreasing amount of albumin adsorbed on the gradient surfaces with increasing diamond/β-SiC ratio. The mechanism of preferential protein adsorption is discussed by considering the hydrogen bonding of the water self-association network to OH-terminated surfaces and the change of the polar surface energy component, which was determined according to the van Oss method. These results suggest that the diamond/β-SiC gradient film can be a promising material for biomedical applications which

  13. Application of Kevin-Voigt Model in Quantifying Whey Protein Adsorption on Polyethersulfone Using QCM-D

    Science.gov (United States)

    The study of protein adsorption on the membrane surface is of great importance to cheese-making processors that use polymeric membrane-based processes to recover whey protein from the process waste streams. Quartz crystal microbalance with dissipation (QCM-D) is a lab-scale, fast analytical techniq...

  14. Using mathematical models to understand the effect of nanoscale roughness on protein adsorption for improving medical devices

    Directory of Open Access Journals (Sweden)

    Ercan B

    2013-09-01

    Full Text Available Batur Ercan,1 Dongwoo Khang,2 Joseph Carpenter,3 Thomas J Webster1 1Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 2School of Materials Science and Engineering and Center for PRC and RIGET, Gyeongsang National University, Jinju, South Korea; 3School of Medicine, Stanford University, Stanford, CA, USA Abstract: Surface roughness and energy significantly influence protein adsorption on to biomaterials, which, in turn, controls select cellular adhesion to determine the success and longevity of an implant. To understand these relationships at a fundamental level, a model was originally proposed by Khang et al to correlate nanoscale surface properties (specifically, nanoscale roughness and energy to protein adsorption, which explained the greater cellular responses on nanostructured surfaces commonly reported in the literature today. To test this model for different surfaces from what was previously used to develop that model, in this study we synthesized highly ordered poly(lactic-co-glycolic acid surfaces of identical chemistry but altered nanoscale surface roughness and energy using poly(dimethylsiloxane molds of polystyrene beads. Fibronectin and collagen type IV adsorption studies showed a linear adsorption behavior as the surface nanoroughness increased. This supported the general trends observed by Khang et al. However, when fitting such data to the mathematical model established by Khang et al, a strong correlation did not result. Thus, this study demonstrated that the equation proposed by Khang et al to predict protein adsorption should be modified to accommodate for additional nanoscale surface property contributions (ie, surface charge to make the model more accurate. In summary, results from this study provided an important step in developing future mathematical models that can correlate surface properties (such as nanoscale roughness and surface energy to initial protein adsorption events important to

  15. Synthesis and characterization of hydroxyapatite nanoparticles and their application in protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez-Hernandez, F., E-mail: fvazquez@cinvestav.mx [Centro de Investigacion y Estudios Avanzados del Instituto Politecnico Nacional, Departamento de Ingenieria Electrica, Distrito Federal 07360 (Mexico); Mendoza-Barrera, C.; Altuzar, V. [Universidad Veracruzana, MICRONA, Laboratorio de Bionanotecnologia, Boca del Rio, Veracruz 94294 (Mexico); Melendez-Lira, M. [Centro de Investigacion y Estudios Avanzados del Instituto Politecnico Nacional, Departamento de Fisica, Distrito Federal 07360 (Mexico); Santana-Aranda, M.A. [Universidad de Guadalajara, CUCEI, Departamento de Fisica, Guadalajara, Jalisco 44430 (Mexico); Olvera, M. de la L [Centro de Investigacion y Estudios Avanzados del Instituto Politecnico Nacional, Departamento de Ingenieria Electrica, Distrito Federal 07360 (Mexico)

    2010-10-25

    Hydroxyapatite (HAp) is a bioceramic material used to decrease the operatory time for bone trauma fixing, protein purification, prosthetic covering, and complementing the consolidation and substitution in bone solutions since this material works in favor of the bone neoformation when it is in touch with the physiological tissue. In this work the hydrothermal method, by using a starting solution containing hydrate dipotassium hydrogen phosphate, K{sub 2}HPO{sub 4}.3H{sub 2}O, and cetyltrimethylammonium bromide, CTAB, dissolved in deionized water was employed to synthesize HAp nanoparticles with sizes between 15 and 60 nm, high policrystallinity and Ca/P and Ca/O ratios close to the theoretical. The synthesized HAp particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Pellets with a diameter of 5 mm and weight of 150 mg were used to support the fibrinogen (FGN) and bovine serum albumin (BSA) adsorption (0.15, 0.7, and 1.5 mg/ml) studies. The protein adsorption studies were carried out via atomic force microscopy (AFM).

  16. Enhanced Hydrophilicity and Protein Adsorption of Titanium Surface by Sodium Bicarbonate Solution

    Directory of Open Access Journals (Sweden)

    Shengnan Jia

    2015-01-01

    Full Text Available The aim of this study was to investigate a novel and convenient method of chemical treatment to modify the hydrophilicity of titanium surfaces. Sand-blasted and acid-etched (SLA titanium surfaces and machined titanium surfaces were treated with sodium bicarbonate (NaHCO3 solution. The wetting behavior of both kinds of surfaces was measured by water contact angle (WCA test. The surface microstructure was assessed with scanning electron microscopy (SEM and three-dimensional (3D optical microscopy. The elemental compositions of the surfaces were analyzed by X-ray photoelectron spectroscopy (XPS. The protein adsorption analysis was performed with fibronectin. Results showed that, after 1 M NaHCO3 treatment, the hydrophilicity of both SLA and machined surfaces was enhanced. No significant microstructural change presented on titanium surfaces after NaHCO3 treatment. The deprotonation and ion exchange activities might cause the enhanced hydrophilicity of titanium surfaces. The increased protein adsorption of NaHCO3-treated SLA surfaces might indicate their improved tissue-integration in clinical use.

  17. A novel system for continuous protein refolding and on-line capture by expanded bed adsorption

    DEFF Research Database (Denmark)

    Ferré, Henrik; Ruffet, E; Nielsen, L.L.B

    2005-01-01

    A novel two-step protein refolding strategy has been developed, where continuous renaturation-by-dilution is followed by direct capture on an expanded bed adsorption (EBA) column. The performance of the overall process was tested on a N-terminally tagged version of human beta(2)-microglobulin (HAT......-h beta(2)m) both at analytical, small, and preparative scale. In a single scalable operation, extracted and denatured inclusion body proteins from Escherichia coli were continuously diluted into refolding buffer, using a short pipe reactor, allowing for a defined retention and refolding time...... of the overall process was 45%, and the product loss was primarily a consequence of the refolding reaction rather than the EBA step. Full biological activity of HAT-h beta(2)m was demonstrated after removal of the HAT-tag. In contrast to batch refolding, a continuous refolding strategy allows the conditions...

  18. Preparation of Cu{sup 2+}/NTA-derivatized branch polyglycerol magnetic nanoparticles for protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    ShiXing Wang, E-mail: wsxkm@sina.com; Sun Wentong [Yunnan Institute of Product Quality Supervision and Inspection (China); Zhou Yang, E-mail: zhouyang8250@sohu.co [Kunming University of Science and Technology, Faculty of Metallurgical and Energy Engineering (China)

    2010-09-15

    In this report, we described the preparation of Cu{sup 2+}/nitrilotriacetic acids (NTA)-derivatized branch polyglycerol magnetic nanoparticles for protein adsorption with avoidance of nonspecific interactions at the same time. Magnetic nanoparticles (MNPs) were synthesized by the coprecipitation method. The transmission electron microscopy results showed that the average diameter of MNPs was 15.8 {+-} 4.6 nm. X-ray photoelectron spectroscopy and Fourier Transform infrared measurements indicated that branch polyglycerols were grafted on MNPs via the ring-opening polymerization of glycidol and that Cu{sup 2+} ions had been successfully immobilized on the surface of MNPs. The protein immobilization effect was characterized by UV-Vis spectrum. The results proved that Cu{sup 2+}/NTA-derivatized branch polyglycerol magnetic nanoparticles effectively adsorbed bovine haemoglobin and rarely adsorbed lysozyme and {gamma}-globin.

  19. Surface adsorption of lattice HP proteins: Thermodynamics and structural transitions using Wang-Landau sampling

    International Nuclear Information System (INIS)

    Li Yingwai; Landau, David P; Wüst, Thomas

    2012-01-01

    Wang-Landau sampling has been applied to investigate the thermodynamics and structural properties of a lattice hydrophobic-polar heteropolymer (the HP protein model) interacting with an attractive substrate. For simplicity, we consider a short HP sequence consisting of only 36 monomers interacting with a substrate which attracts all monomers in the sequence. The conformational “phase transitions” have been identified by a canonical analysis of the specific heat and suitable structural observables. Three major “transitions”, namely, adsorption, hydrophobic core formation and “flattening” of adsorbed structures, are observed. Depending on the surface attractive strength relative to the intra-protein attraction among the H monomers, these processes take place in different sequences upon cooling.

  20. Elucidating the mechanisms of protein antigen adsorption to the CAF/NAF liposomal vaccine adjuvant systems

    DEFF Research Database (Denmark)

    Hamborg, Mette; Rose, Fabrice; Jorgensen, Lene

    2014-01-01

    is generally known about how antigens and adjuvants interact at the molecular level. The aim of this study was to elucidate the mechanisms of interactions between the equally sized, but oppositely charged model protein antigens α-lactalbumin and lysozyme, and i) the clinically tested cationic liposomal...... antigens are presented to antigen-presenting cells, and may play an important role for the efficacy of the vaccine-induced immune response. These studies thus exemplify the importance of characterizing the molecular interactions between the vaccine antigen and adjuvant along with immunogenicity......The reverse vaccinology approach has recently resulted in the identification of promising protein antigens, which in combination with appropriate adjuvants can stimulate customized, protective immune responses. Although antigen adsorption to adjuvants influences vaccine efficacy and safety, little...

  1. Interplay between grain structure and protein adsorption on functional response of osteoblasts: ultrafine-grained versus coarse-grained substrates.

    Science.gov (United States)

    Misra, R D K; Nune, C; Pesacreta, T C; Somani, M C; Karjalainen, L P

    2013-01-01

    The rapid adsorption of proteins is the starting and primary biological response that occurs when a biomedical device is implanted in the physiological system. The biological response, however, depends on the surface characteristics of the device. Considering the significant interest in nano-/ultrafine surfaces and nanostructured coatings, we describe here, the interplay between grain structure and protein adsorption (bovine serum albumin: BSA) on osteoblasts functions by comparing nanograined/ultrafine-grained (NG/UFG) and coarse-grained (CG: grain size in the micrometer range) substrates by investigating cell-substrate interactions. The protein adsorption on NG/UFG surface was beneficial in favorably modulating biological functions including cell attachment, proliferation, and viability, whereas the effect was less pronounced on protein adsorbed CG surface. Additionally, immunofluorescence studies demonstrated stronger vinculin signals associated with actin stress fibers in the outer regions of the cells and cellular extensions on protein adsorbed NG/UFG surface. The functional response followed the sequence: NG/UFG(BSA) > NG/UFG > CG(BSA) > CG. The differences in the cellular response on bare and protein adsorbed NG/UFG and CG surfaces are attributed to cumulative contribution of grain structure and degree of hydrophilicity. The study underscores the potential advantages of protein adsorption on artificial biomedical devices to enhance the bioactivity and regulate biological functions. Copyright © 2012 Wiley Periodicals, Inc.

  2. Surface properties of nanocrystalline TiO2 coatings in relation to the in vitro plasma protein adsorption

    International Nuclear Information System (INIS)

    Lorenzetti, M; Kobe, S; Novak, S; Bernardini, G; Santucci, A; Luxbacher, T

    2015-01-01

    This study reports on the selective adsorption of whole plasma proteins on hydrothermally (HT) grown TiO 2 -anatase coatings and its dependence on the three main surface properties: surface charge, wettability and roughness. The influence of the photo-activation of TiO 2 by UV irradiation was also evaluated. Even though the protein adhesion onto Ti-based substrates was only moderate, better adsorption of any protein (at pH = 7.4) occurred for the most negatively charged and hydrophobic substrate (Ti non-treated) and for the most nanorough and hydrophilic surface (HT Ti3), indicating that the mutual action of the surface characteristics is responsible for the attraction and adhesion of the proteins. The HT coatings showed a higher adsorption of certain proteins (albumin ‘passivation’ layer, apolipoproteins, vitamin D-binding protein, ceruloplasmin, α-2-HS-glycoprotein) and higher ratios of albumin to fibrinogen and albumin to immunoglobulin γ-chains. The UV pre-irradiation affected the surface properties and strongly reduced the adsorption of the proteins. These results provide in-depth knowledge about the characterization of nanocrystalline TiO 2 coatings for body implants and provide a basis for future studies on the hemocompatibility and biocompatibility of such surfaces. (paper)

  3. Quantification of protein based on single-molecule counting by total internal reflection fluorescence microscopy with adsorption equilibrium

    International Nuclear Information System (INIS)

    Wang Lei; Xu Guang; Shi Zhikun; Jiang Wei; Jin Wenrui

    2007-01-01

    We developed a sensitive single-molecule imaging method for quantification of protein by total internal reflection fluorescence microscopy with adsorption equilibrium. In this method, the adsorption equilibrium of protein was achieved between solution and glass substrate. Then, fluorescence images of protein molecules in a evanescent wave field were taken by a highly sensitive electron multiplying charge coupled device. Finally, the number of fluorescent spots corresponding to the protein molecules in the images was counted. Alexa Fluor 488-labeled goat anti-rat IgG(H + L) was chosen as the model protein. The spot number showed an excellent linear relationship with protein concentration. The concentration linear range was 5.4 x 10 -11 to 8.1 x 10 -10 mol L -1

  4. Quantitative surface studies of protein adsorption by infrared spectroscopy. II. Quantification of adsorbed and bulk proteins

    International Nuclear Information System (INIS)

    Fink, D.J.; Hutson, T.B.; Chittur, K.K.; Gendreau, R.M.

    1987-01-01

    Attenuated total reflectance Fourier transform infrared spectra of surface-adsorbed proteins are correlated with concentration measurements determined by 125 I-labeled proteins. This paper demonstrates that linear correlations between the intensity of the major bands of proteins and the quantity of proteins can be obtained for human albumin and immunoglobulin G up to surface concentrations of approximately 0.25 microgram/cm2. A poorer correlation was observed for human fibrinogen. A linear correlation was also observed between the concentration in the bulk solution and the major bands of albumin up to a concentration of 60 mg/ml

  5. Preparation of mesoporous silica thin films by photocalcination method and their adsorption abilities for various proteins

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Katsuya, E-mail: katsuya-kato@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Nakamura, Hitomi [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Yamauchi, Yoshihiro; Nakanishi, Kazuma; Tomita, Masahiro [Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8570 (Japan)

    2014-07-01

    Mesoporous silica (MPS) thin film biosensor platforms were established. MPS thin films were prepared from tetraethoxysilane (TEOS) via using sol–gel and spin-coating methods using a poly-(ethylene oxide)-block-poly-(propylene oxide)-block-poly-(ethylene oxide) triblock polymer, such as P123 ((EO){sub 20}(PO){sub 70}(EO){sub 20}) or F127 ((EO){sub 106}(PO){sub 70}(EO){sub 106}), as the structure-directing agent. The MPS thin film prepared using P123 as the mesoporous template and treated via vacuum ultraviolet (VUV) irradiation to remove the triblock copolymer had a more uniform pore array than that of the corresponding film prepared via thermal treatment. Protein adsorption and enzyme-linked immunosorbent assay (ELISA) on the synthesized MPS thin films were also investigated. VUV-irradiated MPS thin films adsorbed a smaller quantity of protein A than the thermally treated films; however, the human immunoglobulin G (IgG) binding efficiency was higher on the former. In addition, protein A–IgG specific binding on MPS thin films was achieved without using a blocking reagent; i.e., nonspecific adsorption was inhibited by the uniform pore arrays of the films. Furthermore, VUV-irradiated MPS thin films exhibited high sensitivity for ELISA testing, and cytochrome c adsorbed on the MPS thin films exhibited high catalytic activity and recyclability. These results suggest that MPS thin films are attractive platforms for the development of novel biosensors. - Highlights: • VUV-treated MPS thin films with removed polymer had uniform pore. • VUV-treated MPS thin films exhibited high sensitivity by ELISA. • Cytochrome c showed the catalytic activity and recyclability on synthesized films.

  6. Preparation of mesoporous silica thin films by photocalcination method and their adsorption abilities for various proteins

    International Nuclear Information System (INIS)

    Kato, Katsuya; Nakamura, Hitomi; Yamauchi, Yoshihiro; Nakanishi, Kazuma; Tomita, Masahiro

    2014-01-01

    Mesoporous silica (MPS) thin film biosensor platforms were established. MPS thin films were prepared from tetraethoxysilane (TEOS) via using sol–gel and spin-coating methods using a poly-(ethylene oxide)-block-poly-(propylene oxide)-block-poly-(ethylene oxide) triblock polymer, such as P123 ((EO) 20 (PO) 70 (EO) 20 ) or F127 ((EO) 106 (PO) 70 (EO) 106 ), as the structure-directing agent. The MPS thin film prepared using P123 as the mesoporous template and treated via vacuum ultraviolet (VUV) irradiation to remove the triblock copolymer had a more uniform pore array than that of the corresponding film prepared via thermal treatment. Protein adsorption and enzyme-linked immunosorbent assay (ELISA) on the synthesized MPS thin films were also investigated. VUV-irradiated MPS thin films adsorbed a smaller quantity of protein A than the thermally treated films; however, the human immunoglobulin G (IgG) binding efficiency was higher on the former. In addition, protein A–IgG specific binding on MPS thin films was achieved without using a blocking reagent; i.e., nonspecific adsorption was inhibited by the uniform pore arrays of the films. Furthermore, VUV-irradiated MPS thin films exhibited high sensitivity for ELISA testing, and cytochrome c adsorbed on the MPS thin films exhibited high catalytic activity and recyclability. These results suggest that MPS thin films are attractive platforms for the development of novel biosensors. - Highlights: • VUV-treated MPS thin films with removed polymer had uniform pore. • VUV-treated MPS thin films exhibited high sensitivity by ELISA. • Cytochrome c showed the catalytic activity and recyclability on synthesized films

  7. Mechanical properties of protein adsorption layers at the air/water and oil/water interface: a comparison in light of the thermodynamical stability of proteins.

    Science.gov (United States)

    Mitropoulos, Varvara; Mütze, Annekathrin; Fischer, Peter

    2014-04-01

    Over the last decades numerous studies on the interfacial rheological response of protein adsorption layers have been published. The comparison of these studies and the retrieval of a common parameter to compare protein interfacial activity are hampered by the fact that different boundary conditions (e.g. physico-chemical, instrumental, interfacial) were used. In the present work we review previous studies and attempt a unifying approach for the comparison between bulk protein properties and their adsorption films. Among many common food grade proteins we chose bovine serum albumin, β-lactoglobulin and lysozyme for their difference in thermodynamic stability and studied their adsorption at the air/water and limonene/water interface. In order to achieve this we have i) systematically analyzed protein adsorption kinetics in terms of surface pressure rise using a drop profile analysis tensiometer and ii) we addressed the interfacial layer properties under shear stress using an interfacial shear rheometer under the same experimental conditions. We could show that thermodynamically less stable proteins adsorb generally faster and yield films with higher shear rheological properties at air/water interface. The same proteins showed an analog behavior when adsorbing at the limonene/water interface but at slower rates. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Adsorption and Desorption of Bioactive Proteins on Hydroxyapatite for Protein Delivery Systems

    Directory of Open Access Journals (Sweden)

    Chie Kojima

    2012-01-01

    Full Text Available Hydroxyapatite (HA is a precursor of bone and has been studied as a biomaterial. We attempted HA to apply to protein delivery systems. In this study, the association and dissociation properties of two types of bioactive proteins, cytochrom c and insulin, to HA were investigated. Cytochrom c was less associated with HA than insulin, which was easily released from it. However, the release of insulin from HA was slow. Insulin was released from HA at pH 7.4 more rapidly than at pH 3. The association and dissociation properties might be influenced by the size, solubility and net charge of protein. HA is a potential protein carrier with controlled release.

  9. Effects of thermal treatments on protein adsorption of Co-Cr-Mo ASTM-F75 alloys.

    Science.gov (United States)

    Duncan, L A; Labeed, F H; Abel, M-L; Kamali, A; Watts, J F

    2011-06-01

    Post-manufacturing thermal treatments are commonly employed in the production of hip replacements to reduce shrinkage voids which can occur in cast components. Several studies have investigated the consequences of these treatments upon the alloy microstructure and tribological properties but none have determined if there are any biological ramifications. In this study the adsorption of proteins from foetal bovine serum (FBS) on three Co-Cr-Mo ASTM-F75 alloy samples with different metallurgical histories, has been studied as a function of protein concentration. Adsorption isotherms have been plotted using the surface concentration of nitrogen as a diagnostic of protein uptake as measured by X-ray photoelectron spectroscopy. The data was a good fit to the Langmuir adsorption isotherm up to the concentration at which critical protein saturation occurred. Differences in protein adsorption on each alloy have been observed. This suggests that development of the tissue/implant interface, although similar, may differ between as-cast (AC) and heat treated samples.

  10. [Blood plasma protein adsorption capacity of perfluorocarbon emulsion stabilized by proxanol 268 (in vitro and in vivo studies)].

    Science.gov (United States)

    Sklifas, A N; Zhalimov, V K; Temnov, A A; Kukushkin, N I

    2012-01-01

    The adsorption abilities of the perfluorocarbon emulsion stabilized by Proxanol 268 were investigated in vitro and in vivo. In vitro, the saturation point for the blood plasma proteins was nearly reached after five minutes of incubation of the emulsion with human/rabbit blood plasma and was stable for all incubation periods studied. The decrease in volume ratio (emulsion/plasma) was accompanied by the increase in the adsorptive capacity of the emulsion with maximal values at 1/10 (3.2 and 1.5 mg of proteins per 1 ml of the emulsion, for human and rabbit blood plasma, respectively) that was unchanged at lower ratios. In vivo, in rabbits, intravenously injected with the emulsion, the proteins with molecular masses of 12, 25, 32, 44, 55, 70, and 200 kDa were adsorbed by the emulsion (as in vitro) if it was used 6 hours or less before testing. More delayed testing (6 h) revealed elimination of proteins with molecular masses of 25 and 44 kDa and an additional pool of adsorpted new ones of 27, 50, and 150 kDa. Specific adsorptive capacity of the emulsion enhanced gradually after emulsion injection and reached its maximum (3.5-5 mg of proteins per 1 ml of the emulsion) after 24 hours.

  11. The role of PEG conformation in mixed layers: from protein corona substrate to steric stabilization avoiding protein adsorption

    Directory of Open Access Journals (Sweden)

    Joan Comenge

    2015-03-01

    Full Text Available Although nanoparticles (NPs have been traditionally modified with a single ligand layer, mixture of ligands might help to combine different functionalities and to further engineer the NP surface. A detailed study of the competition between an alkanethiol (11-mercaptoundecanoic acid and SH-PEG for the surface of AuNPs and the resultant behaviors of this model nanoconjugate is presented here. As a result, the physicochemical properties of these conjugates can be progressively tuned by controlling the composition and especially the conformation of the mixed monolayer. This has implications in the physiological stability. The controlled changes on the SH-PEG conformation rather than its concentration induce a change in the stabilization mechanism from electrostatic repulsion to steric hindrance, which changes the biological fate of NPs. Importantly, the adsorption of proteins on the conjugates can be tailored by tuning the composition and conformation of the mixed layer.

  12. The adsorption and unfolding kinetics determines the folding state of proteins at the air-water interface and thereby the equation of state

    NARCIS (Netherlands)

    Wierenga, P.A.; Egmond, M.R.; Voragen, A.G.J.; Jongh, H.H.J.de

    2006-01-01

    Unfolding of proteins has often been mentioned as an important factor during the adsorption process at air-water interfaces and in the increase of surface pressure at later stages of the adsorption process. This work focuses on the question whether the folding state of the adsorbed protein depends

  13. Modulation of Protein Adsorption and Cell Proliferation on Polyethylene Immobilized Graphene Oxide Reinforced HDPE Bionanocomposites.

    Science.gov (United States)

    Upadhyay, Rahul; Naskar, Sharmistha; Bhaskar, Nitu; Bose, Suryasarathi; Basu, Bikramjit

    2016-05-18

    The uniform dispersion of nanoparticles in a polymer matrix, together with an enhancement of interfacial adhesion is indispensable toward achieving better mechanical properties in the nanocomposites. In the context to biomedical applications, the type and amount of nanoparticles can potentially influence the biocompatibility. To address these issues, we prepared high-density polyethylene (HDPE) based composites reinforced with graphene oxide (GO) by melt mixing followed by compression molding. In an attempt to tailor the dispersion and to improve the interfacial adhesion, we immobilized polyethylene (PE) onto GO sheets by nucleophilic addition-elimination reaction. A good combination of yield strength (ca. 20 MPa), elastic modulus (ca. 600 MPa), and an outstanding elongation at failure (ca. 70%) were recorded with 3 wt % polyethylene grafted graphene oxide (PE-g-GO) reinforced HDPE composites. Considering the relevance of protein adsorption as a biophysical precursor to cell adhesion, the protein adsorption isotherms of bovine serum albumin (BSA) were determined to realize three times higher equilibrium constant (Keq) for PE-g-GO-reinforced HDPE composites as compared to GO-reinforced composites. To assess the cytocompatibility, we grew osteoblast cell line (MC3T3) and human mesenchymal stem cells (hMSCs) on HDPE/GO and HDPE/PE-g-GO composites, in vitro. The statistically significant increase in metabolically active cell over different time periods in culture for up to 6 days in MC3T3 and 7 days for hMSCs was observed, irrespective of the substrate composition. Such observation indicated that HDPE with GO or PE-g-GO addition (up to 3 wt %) can be used as cell growth substrate. The extensive proliferation of cells with oriented growth pattern also supported the fact that tailored GO addition can support cellular functionality in vitro. Taken together, the experimental results suggest that the PE-g-GO in HDPE can effectively be utilized to enhance both mechanical and

  14. Development of a tuned interfacial force field parameter set for the simulation of protein adsorption to silica glass.

    Science.gov (United States)

    Snyder, James A; Abramyan, Tigran; Yancey, Jeremy A; Thyparambil, Aby A; Wei, Yang; Stuart, Steven J; Latour, Robert A

    2012-12-01

    Adsorption free energies for eight host-guest peptides (TGTG-X-GTGT, with X = N, D, G, K, F, T, W, and V) on two different silica surfaces [quartz (100) and silica glass] were calculated using umbrella sampling and replica exchange molecular dynamics and compared with experimental values determined by atomic force microscopy. Using the CHARMM force field, adsorption free energies were found to be overestimated (i.e., too strongly adsorbing) by about 5-9 kcal/mol compared to the experimental data for both types of silica surfaces. Peptide adsorption behavior for the silica glass surface was then adjusted using a modified version of the CHARMM program, which we call dual force-field CHARMM, which allows separate sets of nonbonded parameters (i.e., partial charge and Lennard-Jones parameters) to be used to represent intra-phase and inter-phase interactions within a given molecular system. Using this program, interfacial force field (IFF) parameters for the peptide-silica glass systems were corrected to obtain adsorption free energies within about 0.5 kcal/mol of their respective experimental values, while IFF tuning for the quartz (100) surface remains for future work. The tuned IFF parameter set for silica glass will subsequently be used for simulations of protein adsorption behavior on silica glass with greater confidence in the balance between relative adsorption affinities of amino acid residues and the aqueous solution for the silica glass surface.

  15. Effects of solution chemistry and aging time on prion protein adsorption and replication of soil-bound prions.

    Directory of Open Access Journals (Sweden)

    Samuel E Saunders

    2011-04-01

    Full Text Available Prion interactions with soil may play an important role in the transmission of chronic wasting disease (CWD and scrapie. Prions are known to bind to a wide range of soil surfaces, but the effects of adsorption solution chemistry and long-term soil binding on prion fate and transmission risk are unknown. We investigated HY TME prion protein (PrP(Sc adsorption to soil minerals in aqueous solutions of phosphate buffered saline (PBS, sodium chloride, calcium chloride, and deionized water using western blotting. The replication efficiency of bound prions following adsorption in these solutions was also evaluated by protein misfolding cyclic amplification (PMCA. Aging studies investigated PrP(Sc desorption and replication efficiency up to one year following adsorption in PBS or DI water. Results indicate that adsorption solution chemistry can affect subsequent prion replication or desorption ability, especially after incubation periods of 30 d or longer. Observed effects were minor over the short-term (7 d or less. Results of long-term aging experiments demonstrate that unbound prions or prions bound to a diverse range of soil surfaces can readily replicate after one year. Our results suggest that while prion-soil interactions can vary with solution chemistry, prions bound to soil could remain a risk for transmitting prion diseases after months in the environment.

  16. Synthesis and characterization of antifouling poly(N-acryloylaminoethoxyethanol) with ultralow protein adsorption and cell attachment.

    Science.gov (United States)

    Chen, Hong; Zhang, Mingzhen; Yang, Jintao; Zhao, Chao; Hu, Rundong; Chen, Qiang; Chang, Yung; Zheng, Jie

    2014-09-02

    Rational design of effective antifouling polymers is challenging but important for many fundamental and applied applications. Herein we synthesize and characterize an N-acryloylaminoethoxyethanol (AAEE) monomer, which integrates three hydrophilic groups of hydroxyl, amide, and ethylene glycol in the same material. AAEE monomers were further grafted and polymerized on gold substrates to form polyAAEE brushes with well-controlled thickness via surface-initiated atomic transfer radical polymerization (SI-ATRP), with particular attention to a better understanding of the molecular structure-antifouling property relationship of hydroxyl-acrylic-based polymers. The surface hydrophilicity and antifouling properties of polyAAEE brushes as a function of film thickness are studied by combined experimental and computational methods including surface plasmon resonance (SPR) sensors, atomic force microscopy (AFM), cell adhesion assay, and molecular dynamics (MD) simulations. With the optimal polymer film thicknesses (∼10-40 nm), polyAAEE-grafted surfaces can effectively resist protein adsorption from single-protein solutions and undiluted human blood plasma and serum to a nonfouling level (i.e., antifouling properties. The molecular structure-antifouling properties relationship of a series of hydroxyl-acrylic-based polymers is also discussed. This work hopefully provides a promising structural motif for the design of new effective antifouling materials beyond traditional ethylene glycol-based antifouling materials.

  17. Tissue-engineered matrices as functional delivery systems: adsorption and release of bioactive proteins from degradable composite scaffolds.

    Science.gov (United States)

    Cushnie, Emily K; Khan, Yusuf M; Laurencin, Cato T

    2010-08-01

    A tissue-engineered bone graft should imitate the ideal autograft in both form and function. However, biomaterials that have appropriate chemical and mechanical properties for grafting applications often lack biological components that may enhance regeneration. The concept of adding proteins such as growth factors to scaffolds has therefore emerged as a possible solution to improve overall graft design. In this study, we investigated this concept by loading porous hydroxyapatite-poly(lactide-co-glycolide) (HA-PLAGA) scaffolds with a model protein, cytochrome c, and then studying its release in a phosphate-buffered saline solution. The HA-PLAGA scaffold has previously been shown to be bioactive, osteoconductive, and to have appropriate physical properties for tissue engineering applications. The loading experiments demonstrated that the HA-PLAGA scaffold could also function effectively as a substrate for protein adsorption and release. Scaffold protein adsorptive loading (as opposed to physical entrapment within the matrix) was directly related to levels of scaffold HA-content. The HA phase of the scaffold facilitated protein retention in the matrix following incubation in aqueous buffer for periods up to 8 weeks. Greater levels of protein retention time may improve the protein's effective activity by increasing the probability for protein-cell interactions. The ability to control protein loading and delivery simply via composition of the HA-PLAGA scaffold offers the potential of forming robust functionalized bone grafts. (c) 2010 Wiley Periodicals, Inc.

  18. Experimental approach to controllably vary protein oxidation while minimizing electrode adsorption for boron-doped diamond electrochemical surface mapping applications.

    Science.gov (United States)

    McClintock, Carlee S; Hettich, Robert L

    2013-01-02

    Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent (i.e., hydroxyl radicals) for these measurements; however, these approaches range significantly in their complexity and expense of operation. This research expands upon earlier work to enhance the controllability of boron-doped diamond (BDD) electrochemistry as an easily accessible tool for producing hydroxyl radicals in order to oxidize a range of intact proteins. Efforts to modulate the oxidation level while minimizing the adsorption of protein to the electrode involved the use of relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber. Additionally, a different cell activation approach using variable voltage to supply a controlled current allowed us to precisely tune the extent of oxidation in a protein-dependent manner. In order to gain perspective on the level of protein adsorption onto the electrode surface, studies were conducted to monitor protein concentration during electrolysis and gauge changes in the electrode surface between cell activation events. This report demonstrates the successful use of BDD electrochemistry for greater precision in generating a target number of oxidation events upon intact proteins.

  19. The interplay between nanostructured carbon-grafted chitosan scaffolds and protein adsorption on the cellular response of osteoblasts: structure-function property relationship.

    Science.gov (United States)

    Depan, D; Misra, R D K

    2013-04-01

    The rapid adsorption of proteins occurs during the early stages of biomedical device implantation into physiological systems. In this regard, the adsorption of proteins is a strong function of the nature of a biomedical device, which ultimately governs the biological functions. The objective of this study was to elucidate the interplay between nanostructured carbon-modified (graphene oxide and single-walled carbon nanohorn) chitosan scaffolds and consequent protein adsorption and biological function (osteoblast function). We compare and contrast the footprint of protein adsorption on unmodified chitosan and nanostructured carbon-modified chitosan. A comparative analysis of cell-substrate interactions using an osteoblast cell line (MC3T3-E1) implied that biological functions were significantly enhanced in the presence of nanostructured carbon, compared with unmodified chitosan. The difference in their respective behaviors is related to the degree and topography of protein adsorption on the scaffolds. Furthermore, there was a synergistic effect of nanostructured carbon and protein adsorption in terms of favorably modulating biological functions, including cell attachment, proliferation and viability, with the effect being greater on nanostructured carbon-modified scaffolds. The study also underscores that protein adsorption is favored in nanostructured carbon-modified scaffolds such that bioactivity and biological function are promoted. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Periodic protein adsorption at the gold/biotin aqueous solution interface: evidence of kinetics with time delay

    Science.gov (United States)

    Neff, H.; Laborde, H. M.; Lima, A. M. N.

    2016-11-01

    An oscillatory molecular adsorption pattern of the protein neutravidin from aqueous solution onto gold, in presence of a pre-deposited self assembled mono-molecular biotin film, is reported. Real time surface Plasmon resonance sensing was utilized for evaluation of the adsorption kinetics. Two different fractions were identified: in the initial phase, protein molecules attach irreversibly onto the Biotin ligands beneath towards the jamming limit, forming a neutravidin-biotin fraction. Afterwards, the growth rate exhibits distinct, albeit damped adsorption-desorption oscillations over an extended time span, assigned to a quasi reversibly bound fraction. These findings agree with, and firstly confirm a previously published model, proposing macro-molecular adsorption with time delay. The non-linear dynamic model is applicable to and also resembles non-damped oscillatory binding features of the hetero-catalytic oxidation of carbon monoxide molecules on platinum in the gas phase. An associated surface residence time can be linked to the dynamics and time scale required for self-organization.

  1. Adsorption properties of BSA and DsRed proteins deposited on thin SiO2 layers: optically non-absorbing versus absorbing proteins

    Science.gov (United States)

    Scarangella, A.; Soumbo, M.; Villeneuve-Faure, C.; Mlayah, A.; Bonafos, C.; Monje, M.-C.; Roques, C.; Makasheva, K.

    2018-03-01

    Protein adsorption on solid surfaces is of interest for many industrial and biomedical applications, where it represents the conditioning step for micro-organism adhesion and biofilm formation. To understand the driving forces of such an interaction we focus in this paper on the investigation of the adsorption of bovine serum albumin (BSA) (optically non-absorbing, model protein) and DsRed (optically absorbing, naturally fluorescent protein) on silica surfaces. Specifically, we propose synthesis of thin protein layers by means of dip coating of the dielectric surface in protein solutions with different concentrations (0.01-5.0 g l-1). We employed spectroscopic ellipsometry as the most suitable and non-destructive technique for evaluation of the protein layers’ thickness and optical properties (refractive index and extinction coefficient) after dehydration, using two different optical models, Cauchy for BSA and Lorentz for DsRed. We demonstrate that the thickness, the optical properties and the wettability of the thin protein layers can be finely controlled by proper tuning of the protein concentration in the solution. These results are correlated with the thin layer morphology, investigated by AFM, FTIR and PL analyses. It is shown that the proteins do not undergo denaturation after dehydration on the silica surface. The proteins arrange themselves in a lace-like network for BSA and in a rod-like structure for DsRed to form mono- and multi-layers, due to different mechanisms driving the organization stage.

  2. Influence of boron addition to Ti–13Zr–13Nb alloy on MG63 osteoblast cell viability and protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, P., E-mail: m.pallab@gmail.com [School of Mechanical Science, Indian Institute of Technology, Bhubaneswar (India); Singh, S.B. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur (India); Dhara, S. [School Medical Science and Technology, Indian Institute of Technology, Kharagpur (India); Chakraborty, M. [School of Mechanical Science, Indian Institute of Technology, Bhubaneswar (India)

    2015-01-01

    Cell proliferation, cell morphology and protein adsorption on near β-type Ti–13Zr–13Nb (TZN) alloy and Ti–13Zr–13Nb–0.5B (TZNB) composite have been investigated and compared to evaluate the effect of boron addition which has been added to the Ti alloy to improve their poor tribological properties by forming in situ TiB precipitates. MG63 cell proliferation on substrates with different chemistry but the same topography was compared. The MTT assay test showed that the cell viability on the TZN alloy was higher than the boron containing TZNB composite after 36 h of incubation and the difference was pronounced after 7 days. However, both the materials showed substantially higher cell attachment than the control (polystyrene). For the same period of incubation in fetal bovine serum (FBS), the amount of protein adsorbed on the surface of boron free TZN samples was higher than that in the case of boron containing TZNB composite. The presence of boron in the TZN alloy influenced protein adsorption and cell response and they are lower in TZNB than in TZN as a result of the associated difference in chemical characteristics. - Highlights: • The influence of boron addition on biocompatibility of Ti–13Zr–13Nb • Boron forms in situ TiB in TZN matrix and decreases cell proliferation on TZN surfaces. • Protein adsorption is lower in TZNB than in TZN. • Compared to TZNB composite, TZN alloy is more suitable for bone grafting applications.

  3. One-step polymer surface modification for minimizing drug, protein, and DNA adsorption in microanalytical systems

    DEFF Research Database (Denmark)

    Larsen, Esben Kjær Unmack; Larsen, Niels Bent

    2013-01-01

    The non-specific adsorption of dissolved analytes strongly reduces the sensitivity and reliability in polymer microanalytical systems. Here, a one-step aqueous phase procedure modifies polymer material surfaces to strongly reduce their non-specific adsorption of a broad range of organic analytes ...

  4. Effects of cloud-point grafting, chain length, and density of PEG layers on competitive adsorption of ocular proteins

    DEFF Research Database (Denmark)

    Kingshott, P.; Thissen, H.; Griesser, H.J.

    2002-01-01

    The effects of pinning density, chain length, and 'cloud point' (CP) versus non-CP grafting conditions have been studied on the ability of polyethylene glycol (PEG) layers to minimize adsorption from a multicomponent (lysozyme, human serum albumin (HSA), IgG and lactoferrin) protein solution...... density) r.f.g.d. polymer layers. The PEG graft density was varied also by increasing the temperature and salt (K2SO4) content of the grafting solution; it reached a maximum at the CP of the PEGs. The CP reaction conditions were critical for producing PEG layers capable of minimizing protein adsorption. X...... density and chain length are interrelated, but the key factor is optimization of PEG chain density by use of the CP conditions, provided that a sufficient density of pinning sites exists. (C) 2002 Elsevier Science Ltd. Al l rights reserved....

  5. Resistance to protein adsorption and adhesion of fibroblasts on nanocrystalline diamond films: the role of topography and boron doping

    Czech Academy of Sciences Publication Activity Database

    Alcaide, M.; Papaioannou, S.; Taylor, Andrew; Fekete, Ladislav; Gurevich, L.; Zachar, V.; Pennisi, C.P.

    2016-01-01

    Roč. 27, č. 5 (2016), s. 90-1-12 ISSN 0957-4530 R&D Projects: GA MŠk LO1409 Grant - others:FUNBIO(XE) CZ.2.16/3.1.00/21568 Institutional support: RVO:68378271 Keywords : protein adsorption * fibroblasts adhesion * nanocrystalline diamond * boron doping * topography Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.325, year: 2016

  6. Kinetics of adsorption of whey proteins and hydroxypropyl-methyl-cellulose mixtures at the air-water interface.

    Science.gov (United States)

    Pérez, Oscar E; Carrera Sánchez, Cecilio; Pilosof, Ana M R; Rodríguez Patino, Juan M

    2009-08-15

    The aim of this research is to quantify the competitive adsorption of a whey protein concentrate (WPC) and hydroxypropyl-methyl-cellulose (HPMC so called E4M, E50LV and F4M) at the air-water interface by means of dynamic surface tensiometry and Brewster angle microscopy (BAM). These biopolymers are often used together in many food applications. The concentration of both protein and HPMC, and the WPC/HPMC ratio in the aqueous bulk phase were variables, while pH (7), the ionic strength (0.05 M) and temperature (20 degrees C) were kept constant. The differences observed between mixed systems were in accordance with the relative bulk concentration of these biopolymers (C(HPMC) and C(WPC)) and the molecular structure of HPMC. At short adsorption times, the results show that under conditions where both WPC and HPMC could saturate the air-water interface on their own or when C(HPMC) > or = C(WPC), the polysaccharide dominates the surface. At concentrations where none of the biopolymers was able to saturate the interface, a synergistic behavior was observed for HPMC with lower surface activity (E50LV and F4M), while a competitive adsorption was observed for E4M (the HPMC with the highest surface activity). At long-term adsorption the rate of penetration controls the adsorption of mixed components. The results reflect complex competitive/synergistic phenomena under conditions of thermodynamic compatibility or in the presence of a "depletion mechanism". Finally, the order in which the different components reach the interface will influence the surface composition and the film properties.

  7. The effect of amorphous silicon surface hydrogenation on morphology, wettability and its implication on the adsorption of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Filali, Larbi, E-mail: larbifilali5@gmail.com [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria); Brahmi, Yamina; Sib, Jamal Dine [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria); Bouhekka, Ahmed [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria); Département de Physique, Université Hassiba Ben Bouali, 02000 Chlef (Algeria); Benlakehal, Djamel; Bouizem, Yahya; Kebab, Aissa; Chahed, Larbi [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria)

    2016-10-30

    Highlights: • Hydrogenation of the surfaces had the effect of reducing the roughness by way of shadow etching. • Roughness was the driving factor affecting the wettability of the hydrogenated surfaces. • Bovine Serum Albumin proteins favored the surfaces with highest hydrogen content. • Surface modification induced secondary structure change of adsorbed proteins. - Abstract: We study the effect of amorphous silicon (a-Si) surface hydrogenation on Bovine Serum Albumin (BSA) adsorption. A set of (a-Si) films was prepared by radio frequency magnetron sputtering (RFMS) and after deposition; they were treated in molecular hydrogen ambient at different pressures (1–3 Pa). Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy and spectroscopic ellipsometry (SE) were used to study the hydrogenation effect and BSA adsorption. Atomic force microscopy (AFM) was used to evaluate morphological changes caused by hydrogenation. The wettability of the films was measured using contact angle measurement, and in the case of the hydrogenated surfaces, it was found to be driven by surface roughness. FTIR-ATR spectroscopy and SE measurements show that proteins had the strongest affinity toward the surfaces with the highest hydrogen content and their secondary structure was affected by a significant decrease of the α-helix component (-27%) compared with the proteins adsorbed on the un-treated surface, which had a predominantly α-helix (45%) structure. The adsorbed protein layer was found to be densely packed with a large thickness (30.9 nm) on the hydrogen-rich surfaces. The most important result is that the surface hydrogen content was the dominant factor, compared to wettability and morphology, for protein adsorption.

  8. pH dependence of the kinetics of interfacial tension changes during protein adsorption from sessile droplets on FEP-Teflon

    NARCIS (Netherlands)

    VanderVegt, W; Norde, W; VanderMei, HC; Busscher, HJ

    Interfacial tension changes during protein adsorption at both the solid-liquid and the liquid-vapor interface were measured simultaneously by ADSA-P from sessile droplets of protein solutions on fluoroethylenepropylene-Teflon. Four globular proteins of similar size, viz. lysozyme, ribonuclease,

  9. Multi-component adsorption model for pellicle formation: the influence of salivary proteins and non-salivary phospho proteins on the binding of histatin 5 onto hydroxyapatite.

    Science.gov (United States)

    Yin, A; Margolis, H C; Yao, Y; Grogan, J; Oppenheim, F G

    2006-02-01

    The acquired enamel pellicle formed by selective adsorption of proteins in whole saliva is a protective integument on the tooth surface. The purpose of the present study was to investigate the formation of human acquired enamel pellicle using an in vitro hydroxyapatite (HA) model and 3H-histatin 5 to allow accurate measurement of histatin 5 binding in a multi-component experimental system. A binary system was employed by mixing 3H-histatin 5 with one unlabeled protein prior to incubation with HA or by first incubating 3H-histatin 5 with the HA which had been pre-coated with one of a panel of unlabeled proteins (human albumin, salivary amylase, lysozyme, acidic PIFs, statherin, the N-terminal fragment of statherin, and egg yolk phosvitin). A ternary system was employed by mixing 3H-histatin 5 with HA sequentially pre-coated with two different unlabeled proteins, including recombinant histatin 1. The results showed that only salivary statherin and egg yolk phosvitin promote histatin 5 adsorption significantly. The amount of histatin 5 adsorbed was also found to increase as a function of the amount of phosvitin and statherin used to pre-coat HA up to a maximum level that was two- to four-fold greater than that observed on untreated HA. These data suggest that specific protein-protein interactions may play important roles in pellicle formation in vivo.

  10. Surface adsorption behaviour of milk whey protein and pectin mixtures under conditions of air-water interface saturation.

    Science.gov (United States)

    Perez, Adrián A; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Rubiolo, Amelia C; Santiago, Liliana G

    2011-07-01

    Milk whey proteins (MWP) and pectins (Ps) are biopolymer ingredients commonly used in the manufacture of colloidal food products. Therefore, knowledge of the interfacial characteristics of these biopolymers and their mixtures is very important for the design of food dispersion formulations (foams and/or emulsions). In this paper, we examine the adsorption and surface dilatational behaviour of MWP/Ps systems under conditions in which biopolymers can saturate the air-water interface on their own. Experiments were performed at constant temperature (20 °C), pH 7 and ionic strength 0.05 M. Two MWP samples, β-lactoglobulin (β-LG) and whey protein concentrate (WPC), and two Ps samples, low-methoxyl pectin (LMP) and high-methoxyl pectin (HMP) were evaluated. The contribution of biopolymers (MWP and Ps) to the interfacial properties of mixed systems was evaluated on the basis of their individual surface molecular characteristics. Biopolymer bulk concentration capable of saturating the air-water interface was estimated from surface pressure isotherms. Under conditions of interfacial saturation, dynamic adsorption behaviour (surface pressure and dilatational rheological characteristics) of MWP/Ps systems was discussed from a kinetic point of view, in terms of molecular diffusion, penetration and configurational rearrangement at the air-water interface. The main adsorption mechanism in MWP/LMP mixtures might be the MWP interfacial segregation due to the thermodynamic incompatibility between MWP and LMP (synergistic mechanism); while the interfacial adsorption in MWP/HMP mixtures could be characterized by a competitive mechanism between MWP and HMP at the air-water interface (antagonistic mechanism). The magnitude of these phenomena could be closely related to differences in molecular composition and/or aggregation state of MWP (β-LG and WPC). Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Protein and exercise in the prevention of sarcopenia and aging.

    Science.gov (United States)

    Naseeb, Manal A; Volpe, Stella L

    2017-04-01

    Aging is associated with a progressive decline in skeletal muscle mass and strength. The decline, known as sarcopenia, could lead to physical disability, poor quality of life, and death. In addition, the older population usually experiences age-related muscle changes that affect muscle mass, muscular strength, and functional abilities. The purpose of this review is to describe the role of protein and exercise in slowing the progression of sarcopenia. It will also discuss whether age-related changes can be attenuated by dietary protein and exercise in the older population. This review will also cover one of the possible mechanisms of how dietary protein and exercise are involved in sarcopenia prevention, as well as the available measurement tools. Based on the findings of this review, the adequate amount of protein required for older men and women needs to be revised and likely be higher. Moreover, studies are required to explore some inconclusive findings concerning sarcopenia in the older population. Further research is required to investigate the following: (1) the safety and effectiveness concerning the consumption of 1.4 g of protein/kg of body weight (or more) in this vulnerable population; (2) the effectiveness of amino acid supplementation in reducing progression of sarcopenia over time through longitudinal studies; (3) the preferred source and timing of protein for the older population to maintain muscular strength and attenuate sarcopenia; (4) exercise interventions, especially those of longer duration, in the attenuation of sarcopenia; (5) other types of exercise and their effects on age-related muscle changes; (6) the mechanism of how protein and exercise prevent muscle loss with aging; and (7) determine the best method to diagnose sarcopenia. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Inhibition of the Unfolded Protein Response Mechanism Prevents Cardiac Fibrosis.

    Directory of Open Access Journals (Sweden)

    Jody Groenendyk

    Full Text Available Cardiac fibrosis attributed to excessive deposition of extracellular matrix proteins is a major cause of heart failure and death. Cardiac fibrosis is extremely difficult and challenging to treat in a clinical setting due to lack of understanding of molecular mechanisms leading to cardiac fibrosis and effective anti-fibrotic therapies. The objective in this study was to examine whether unfolded protein response (UPR pathway mediates cardiac fibrosis and whether a pharmacological intervention to modulate UPR can prevent cardiac fibrosis and preserve heart function.We demonstrate here that the mechanism leading to development of fibrosis in a mouse with increased expression of calreticulin, a model of heart failure, stems from impairment of endoplasmic reticulum (ER homeostasis, transient activation of the unfolded protein response (UPR pathway and stimulation of the TGFβ1/Smad2/3 signaling pathway. Remarkably, sustained pharmacologic inhibition of the UPR pathway by tauroursodeoxycholic acid (TUDCA is sufficient to prevent cardiac fibrosis, and improved exercise tolerance.We show that the mechanism leading to development of fibrosis in a mouse model of heart failure stems from transient activation of UPR pathway leading to persistent remodelling of cardiac tissue. Blocking the activation of the transiently activated UPR pathway by TUDCA prevented cardiac fibrosis, and improved prognosis. These findings offer a window for additional interventions that can preserve heart function.

  13. Protein adsorption and cell adhesion on nanoscale bioactive coatings formed from poly(ethylene glycol) and albumin microgels

    Science.gov (United States)

    Scott, Evan A.; Nichols, Michael D.; Cordova, Lee H.; George, Brandon J.; Jun, Young-Shin; Elbert, Donald L.

    2008-01-01

    Late-term thrombosis on drug-eluting stents is an emerging problem that might be addressed using extremely thin, biologically-active hydrogel coatings. We report a dip-coating strategy to covalently link poly(ethylene glycol) (PEG) to substrates, producing coatings with crosslinked microgels and deviation from Flory-Stockmayer theory. Before macrogelation, the reacting solutions were diluted and incubated with nucleophile-functionalized surfaces. Using optical waveguide lightmode spectroscopy (OWLS) and quartz crystal microbalance with dissipation (QCM-D), we identified a highly hydrated, protein-resistant layer with a thickness of approximately 75 nm. Atomic force microscopy in buffered water revealed the presence of coalesced spheres of various sizes but with diameters less than about 100 nm. Microgel-coated glass or poly(ethylene terephthalate) exhibited reduced protein adsorption and cell adhesion. Cellular interactions with the surface could be controlled by using different proteins to cap unreacted vinylsulfone groups within the coating. PMID:18771802

  14. Interfacial dilational properties of tea polyphenols and milk proteins with gut epithelia and the role of mucus in nutrient adsorption.

    Science.gov (United States)

    Guri, Anilda; Li, Yang; Corredig, Milena

    2015-12-01

    By interacting with nutrients, the mucus layer covering the intestinal epithelium may mediate absorption. This study aimed to determine possible interactions between epigallocatechin-3-gallate (EGCG), skim milk proteins or their complexes with human intestinal mucin films. The films were extracted from postconfluent monolayers of HT29-MTX, a human intestinal cell line, and a model system was created using drop shape tensiometry. The EGCG uptake tested in vitro on postconfluent Caco-2 cells or co-cultures of Caco-2/HT29-MTX (mucus producing) showed recovery of bioavailable EGCG only for Caco-2 cell monolayers, suggesting an effect of mucus on absorption. Interfacial dilational rheology was employed to characterize the properties of the interface mixed with mucus dispersion. Adsorption of polyphenols greatly enhanced the viscoelastic modulus of the mucus film, showing the presence of interactions between the nutrient molecules and mucus films. On the other hand, in situ digestion of milk proteins using trypsin showed higher surface activities as a result of protein unfolding and competitive adsorption of the hydrolyzed products. There was an increase of viscoelastic modulus over the drop ageing time for the mixed interfaces, indicating the formation of a stiffer interfacial network. These results bring new insights into the role of the mucus layer in nutrient absorption and the interactions of mucus and dairy products.

  15. Quantitative description of the relation between protein net charge and protein adsorption to air-water interfaces

    NARCIS (Netherlands)

    Wierenga, P.A.; Meinders, M.B.J.; Egmond, M.R.; Voragen, A.G.J.; Jongh, H.H.J.de

    2005-01-01

    In this study a set of chemically engineered variants of ovalbumin was produced to study the effects of electrostatic charge on the adsorption kinetics and resulting surface pressure at the air-water interface. The modification itself was based on the coupling of succinic anhydride to lysine

  16. RAFT of sulfobetaine for modifying poly(glycidyl methacrylate) microspheres to reduce nonspecific protein adsorption

    Czech Academy of Sciences Publication Activity Database

    Koubková, Jana; Macková, Hana; Proks, Vladimír; Trchová, Miroslava; Brus, Jiří; Horák, Daniel

    2015-01-01

    Roč. 53, č. 19 (2015), s. 2273-2284 ISSN 0887-624X R&D Projects: GA MŠk(CZ) LH14318; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : adsorption * grafting * hydrophilic polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.114, year: 2015

  17. Protein adsorption and biomimetic mineralization behaviors of PLL-DNA multilayered films assembled onto titanium

    Energy Technology Data Exchange (ETDEWEB)

    Gao Wenli [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Feng Bo, E-mail: fengbo@swjtu.edu.cn [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Ni Yuxiang [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Yang Yongli [College of Material Science and Engineering, Sichuan University, Chengdu 610054 (China); Lu Xiong; Weng Jie [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2010-11-01

    Titanium and its alloys are frequently used as surgical implants in load bearing situations, such as hip prostheses and dental implants, owing to their biocompatibility, mechanical and physical properties. In this paper, a layer-by-layer (LBL) self-assembly technique, based on the polyelectrolyte-mediated electrostatic adsorption of poly-L-lysine (PLL) and DNA, was used to the formation of multilayer on titanium surfaces. Then bovine serum albumin (BSA) adsorption and biomimetic mineralization of modified surfaces were studied. The chemical composition and wettability of assembled substrates were investigated by X-ray photoelectron spectroscopy (XPS), fluorescence microscopy and water contact angle measurement, respectively. The XPS analysis indicated that the layers were assembled successfully through electrostatic attractions. The measurement with ultraviolet (UV) spectrophotometer revealed that the LBL films enhanced ability of BSA adsorption onto titanium. The adsorption quantity of BSA on the surface terminated with PLL was higher than that of the surface terminated with DNA, and the samples of TiOH/P/D/P absorbed BSA most. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed that samples of assembled PLL or/and DNA had better bioactivity in inducing HA formation. Thus the assembling of PLL and DNA onto the surface of titanium in turn via a layer-by-layer self-assembly technology can improve the bioactivity of titanium.

  18. Adsorption of acidic, basic, and neutral proteins from aqueous samples using Fe3O4 magnetic nanoparticles modified with an ionic liquid

    International Nuclear Information System (INIS)

    Kamran, S.; Asadi, M.; Absalan, G.

    2013-01-01

    We have prepared and characterized Fe 3 O 4 nanoparticles and their binary mixtures (IL-Fe 3 O 4 ) with 1-hexyl-3-methylimidazolium bromide as ionic liquid for use in the adsorption of lysozyme (LYS), bovine serum albumin (BSA), and myoglobin (MYO). The optimum operational conditions for the adsorption of proteins (at 0.05-2.0 mg mL -1 ) were 4.0 mg mL -1 of nanoparticles and a contact time of 10 min. The maximum adsorption capacities are 455, 182 and 143 mg for LYS, BSA, and MYO per gram of adsorbent, respectively. The Langmuir model better fits the adsorption isotherms, with adsorption constants of 0.003, 0.015 and 0.008 L mg -1 , in order, for LYS, BSA, MYO. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium adsorption capacity and correlation coefficients. The adsorption processes are endothermic. The proteins can be desorbed from the nanoparticles by using NaCl solution at pH 9.5, and the nanoparticles thus can be recycled. (author)

  19. Foaming and adsorption behavior of bovine and camel proteins mixed layers at the air/water interface.

    Science.gov (United States)

    Lajnaf, Roua; Picart-Palmade, Laetitia; Attia, Hamadi; Marchesseau, Sylvie; Ayadi, M A

    2017-03-01

    The aim of this work was to examine foaming and interfacial behavior of three milk protein mixtures, bovine α-lactalbumin-β-casein (M1), camel α-lactalbumin-β-casein (M2) and β-lactoglobulin-β-casein (M3), alone and in binary mixtures, at the air/water interface in order to better understand the foaming properties of bovine and camel milks. Different mixture ratios (100:0; 75:25; 50:50; 25:75; 0:100) were used during foaming tests and interfacial protein interactions were studied with a pendant drop tensiometer. Experimental results evidenced that the greatest foam was obtained with a higher β-casein amount in all camel and bovine mixtures. Good correlation was observed with the adsorption and the interfacial rheological properties of camel and bovine protein mixtures. The proteins adsorbed layers are mainly affected by the presence of β-casein molecules, which are probably the most abundant protein at interface and the most efficient in reducing the interfacial properties. In contrast of, the globular proteins, α-lactalbumin and β-lactoglobulin that are involved in the protein layer composition, but could not compact well at the interface to ensure foams creation and stabilization because of their rigid molecular structure. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Is there an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors? Part II

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huajie, E-mail: wanghuajie972001@163.com; Sun Yuanyuan; Cao Ying, E-mail: caoying1130@sina.com; Wang Kui; Yang Lin [Henan Normal University, College of Chemistry and Environmental Science (China); Zhang Yidong; Zheng Zhi [Xuchang University, Institute of Surface Micro and Nano Materials (China)

    2012-05-15

    Although nano-structured surfaces exhibit superior biological activities to the smooth or micro-structured surfaces, whether there is an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors is still controversial. In this study, porous aluminum oxide membranes with different pore sizes ranging from 25 to 120 nm were prepared by the anodic oxidation technique. The surface morphology, topography and wettability were analyzed by scanning electron microscope, atomic force microscope and water contact angle measurement, respectively. The results indicated that the synergistic action of the nano-topography structure and hydrophilic/hydrophobic properties resulted in a highest protein adsorption on the aluminum oxide membrane with 80 nm pore size. Additionally, the morphological, metabolic and cell counting methods showed that cells had different sensitivity to porous aluminum oxide membranes with different surface features. Furthermore, this sensitivity was cell type dependent. The optimal pore size of aluminum oxide membranes for cell growth was 80 nm for PC12 cells and 50 nm for NIH 3T3 cells.

  1. Formation of protein/surfactant adsorption layer at the air/water interface as studied by dilational surface rheology.

    Science.gov (United States)

    Mikhailovskaya, A A; Noskov, B A; Lin, S-Y; Loglio, G; Miller, R

    2011-08-25

    The dynamic dilatational surface elasticity of mixed solutions of globular proteins (β-lactoglobulin (BLG) and bovine serum albumin (BSA)) with cationic (dodecyltrimethylammonium bromide (DTAB)) and anionic (sodium dodecyl sulfate (SDS)) surfactants was measured as a function of the surfactant concentration and surface age. If the cationic surfactant concentration exceeds a certain critical value, the kinetic dependencies of the dynamic surface elasticity of BLG/DTAB and BSA/DTAB solutions become nonmonotonous and resemble those of mixed solutions of proteins with guanidine hydrochloride. This result indicates not only the destruction of the protein tertiary structure in the surface layer of mixed solution but also a strong perturbation of the secondary structure. The corresponding kinetic dependencies for protein solutions with added anionic surfactants are always monotonous, thereby revealing a different mechanism of the adsorption layer formation. One can assume that the secondary structure is destroyed to a lesser extent in the latter case and hinders the formation of loops and tails at the interface. The increase of the solution's ionic strength by the addition of sodium chloride results in stronger changes of the protein conformations in the surface layer and the appearance of a local maximum in the kinetic dependencies of the dynamic surface elasticity in a relatively narrow range of SDS concentration. © 2011 American Chemical Society

  2. Surface modification of poly (styrene-b-(ethylene-co-butylene)-b-styrene) elastomer and its plasma protein adsorption by QCM-D

    Energy Technology Data Exchange (ETDEWEB)

    Li, Rui [Northeast Normal University, School of Physics, Changchun 130022 (China); Jin, Jing, E-mail: jjin@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Sun, Yingchun, E-mail: sunyc149@nenu.edu.cn [Northeast Normal University, School of Physics, Changchun 130022 (China)

    2014-05-01

    Graphical abstract: - Highlights: • Grafting concentration of PEG was defined by the peak-area ratio of [C–O]/[C]. • Quantitatively investigated the adsorption processes of BSA and fibrinogen using QCM-D. • The inactivated BSA on SEBS surface could induce the subsequent fibrinogen adsorption. • SEBS-g-PEG with graft concentration of 0.207 has excellent protein resistance. - Abstract: Protein adsorption is a dynamic process and plays a major role in determining the hemocompatibility of biomaterials. We have obtained different poly (ethylene glycol) (PEG) graft concentrations of SEBS-g-PEG and the surface chemical compositions are confirmed by X-ray photoelectron spectroscopy (XPS). Graft concentration is defined by peak-area ratio of [C-O]/[C] on modified SEBS surface. With increasing graft concentration, water contact angles of the modified SEBS have significantly decreased. The platelet adhesion and static protein adsorption demonstrate that the hemocompatibility of copolymers films are improved effectively and SEBS-g-PEG-2 with larger graft concentration has more superior anticoagulation than that of SEBS-g-PEG-1. Moreover, we have quantitatively investigated the adsorption process of bovine serum albumin (BSA) and fibrinogen (Fib) on the surfaces of pristine SEBS and modified SEBS using quartz crystal microbalance with dissipation (QCM-D) in real time. The results indicate that the inactivated BSA on the pristine SEBS can continuously induce the subsequent Fib adsorption. The hemocompatibility of SEBS-g-PEG-2 with the graft concentration of 0.207 has excellent anti-protein property and the bio-inert BSA layer on the film can resist the subsequent Fib adsorption.

  3. Apatite nano-crystalline surface modification of poly(lactide-co-glycolide) sintered microsphere scaffolds for bone tissue engineering: implications for protein adsorption.

    Science.gov (United States)

    Jabbarzadeh, Ehsan; Nair, Lakshmi S; Khan, Yusuf M; Deng, Meng; Laurencin, Cato T

    2007-01-01

    A number of bone tissue engineering approaches are aimed at (i) increasing the osteconductivity and osteoinductivity of matrices, and (ii) incorporating bioactive molecules within the scaffolds. In this study we examined the growth of a nano-crystalline mineral layer on poly(lactide-co-glycolide) (PLAGA) sintered microsphere scaffolds for tissue engineering. In addition, the influence of the mineral precipitate layer on protein adsorption on the scaffolds was studied. Scaffolds were mineralized by incubation in simulated body fluid (SBF). Scanning electron microscopy (SEM) analysis revealed that mineralized scaffolds possess a rough surface with a plate-like nanostructure covering the surface of microspheres. The results of protein adsorption and release studies showed that while the protein release pattern was similar for PLAGA and mineralized PLAGA scaffolds, precipitation of the mineral layer on PLAGA led to enhanced protein adsorption and slower protein release. Mineralization of tissue-engineered surfaces provides a method for both imparting bioactivity and controlling levels of protein adsorption and release.

  4. Controlled protein adsorption on PMOXA/PAA based coatings by thermally induced immobilization

    Science.gov (United States)

    Mumtaz, Fatima; Chen, Chaoshi; Zhu, Haikun; Pan, Chao; Wang, Yanmei

    2018-05-01

    In this work, poly(2-methyl-2-oxazoline-random-glycidyl methacrylate) (PMOXA-r-GMA) and poly(acrylic acid)-block-poly(glycidyl methacrylate) (PAA-b-PGMA) copolymers were synthesized via cationic ring-opening polymerization (CROP) of 2-methyl-2-oxazoline (MOXA) and reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylic acid (AA) followed by their random and block copolymerization with glycidyl methacrylate (GMA), respectively, and then characterized carefully. PMOXA/PAA based coatings were then prepared by simply spin coating the mixture of PMOXA-r-GMA and PAA-b-PGMA copolymer solutions onto silicon/glass substrates followed by annealing at 110 °C. The coatings were rigorously characterized by using X-ray photoelectron spectroscopy (XPS), the static water contact angle (WCA) test, ellipsometry and atomic force microscopy (AFM). The results demonstrated that the coating based mixed PMOXA/PAA brushes with desired surface composition could be attained by simply maintaining their percentage in the mixture of PMOXA-r-GMA and PAA-b-PGMA copolymer solutions. Finally, the switchable behavior of PMOXA/PAA based coatings toward bovine serum albumin (BSA) adsorption was investigated by fluorescein isothiocyanate-labelled BSA (FITC-BSA) assay and quartz crystal microbalance with dissipation monitoring (QCM-D), which indicated that the coating based mixed PMOXA/PAA brushes could control BSA adsorption/desorption from very low to high amount (>90% desorption) through adjusting the composition of PMOXA-r-GMA and PAA-b-PGMA solution used in preparing PMOXA/PAA based coatings upon pH and ionic strength change. Furthermore, PMOXA/PAA based coatings displayed efficient repeatability of reversible BSA adsorption/desorption cycles.

  5. Protein adsorption resistant surface on polymer composite based on 2D- and 3D-controlled grafting of phospholipid moieties

    International Nuclear Information System (INIS)

    Hoshi, Toru; Matsuno, Ryosuke; Sawaguchi, Takashi; Konno, Tomohiro; Takai, Madoka; Ishihara, Kazuhiko

    2008-01-01

    To prepare the biocompatible surface, a phosphorylcholine (PC) group was introduced on this hydroxyl group generated by surface hydrolysis on the polymer composite composed of polyethylene (PE) and poly (vinyl acetate) (PVAc) prepared by supercritical carbon dioxide. Two different procedures such as two-dimensional (2D) modification and three-dimensional (3D) modification were applied to obtain the steady biocompatible surface. 2D modification was that PC groups were directly anchored on the surface of the polymer composite. 3D modification was that phospholipid polymer was grafted from the surface of the polymer composite by surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-methacryloyloxyethyl phosphorylcholine (MPC). The surfaces were characterized by X-ray photoelectron spectroscopy, dynamic water contact angle measurements, and atomic force microscope. The effects of the poly(MPC) chain length on the protein adsorption resistivity were investigated. The protein adsorption on the polymer composite surface with PC groups modified by 2D or 3D modification was significantly reduced as compared with that on the unmodified PE. Further, the amount of protein adsorbed on the 3D modified surface that is poly(MPC)-grafted surface decreased with an increase in the chain length of the poly(MPC). The surface with an arbitrary structure and the characteristic can be constructed by using 2D and 3D modification. We conclude that the polymer composites of PE/PVAc with PC groups on the surface are useful for fabricating biomedical devices due to their good mechanical and surface properties

  6. A review on adsorption refrigeration technology and adsorption deterioration in physical adsorption systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.C.; Li, Y.H. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Li, D.; Zhang, J.P. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Xia, Y.Z. [Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China)

    2010-01-15

    As one kind of environmentally friendly refrigeration, the adsorption refrigeration has attracted many attentions in resent decades. This paper introduces the researches of adsorption refrigeration systems with the commonly used working pairs, advanced adsorption cycles, heat and mass transfer enhancement and attempts of adsorption refrigeration applications. Poor heat and mass transfer problem is a bottleneck to prevent the improvements of the adsorption refrigeration technique. Two ways to enhance the heat and mass transfer are discussed in this paper. The adsorption deterioration of adsorbent, another obstacle to physical adsorption refrigeration applications, is also pointed out. And the possible reasons and the possible methods are analyzed. (author)

  7. Modification of polyetherurethane for biomedical application by radiation induced grafting. II. Water sorption, surface properties, and protein adsorption of grafted films

    International Nuclear Information System (INIS)

    Jansen, B.; Ellinghorst, G.

    1984-01-01

    A series of polyetherurethane films grafted by means of gamma radiation with hydrophilic or reactive monomers (2-hydroxyethyl methacrylate, 2,3-epoxypropyl methacrylate, 2,3-dihydroxypropyl methacrylate, and acrylamide) and partially chemically modified were subjected to various physico-chemical investigation methods involving water sorption, contact angle, and protein adsorption measurements. From contact angle data the interfacial free energy gamma sw between grafted films and water was calculated. It was found that the water uptake of grafted films increases with grafting yield or, in the case of grafted and afterwards chemically modified films, with reaction yield; the diffusion coefficient of water in the modified films also increases with grafting yield. Contact angle studies revealed all grafted films to have surfaces more hydrophilic than the ungrafted trunk polymer. The degree of hydrophilicity--especially of HEMA-grafted films--strongly depends on grafting conditions. For some grafted samples with high surface hydrophilicity very low interfacial free energies approaching zero were measured. The study of the competitive adsorption of bovine serum albumin, gamma-globulin, and fibrinogen from a synthetic protein solution onto modified films showed that the adsorption of albumin increases markedly with increasing grafting yields, whereas the fibrinogen and gamma-globulin adsorption only slightly increases. A correlation between interfacial free energy and protein adsorption in the sense of the minimum interfacial free energy hypothesis was found only for samples with grafting yields below 5%. At higher grafting yields the increased surface area complicates the analysis

  8. Nanostructured hydroxyapatite surfaces-mediated adsorption alters recognition of BMP receptor IA and bioactivity of bone morphogenetic protein-2.

    Science.gov (United States)

    Huang, Baolin; Yuan, Yuan; Ding, Sai; Li, Jianbo; Ren, Jie; Feng, Bo; Li, Tong; Gu, Yuantong; Liu, Changsheng

    2015-11-01

    Highly efficient loading of bone morphogenetic protein-2 (BMP-2) onto carriers with desirable performance is still a major challenge in the field of bone regeneration. Till now, the nanoscaled surface-induced changes of the structure and bioactivity of BMP-2 remains poorly understood. Here, the effect of nanoscaled surface on the adsorption and bioactivity of BMP-2 was investigated with a series of hydroxyapatite surfaces (HAPs): HAP crystal-coated surface (HAP), HAP crystal-coated polished surface (HAP-Pol), and sintered HAP crystal-coated surface (HAP-Sin). The adsorption dynamics of recombinant human BMP-2 (rhBMP-2) and the accessibility of the binding epitopes of adsorbed rhBMP-2 for BMP receptors (BMPRs) were examined by a quartz crystal microbalance with dissipation. Moreover, the bioactivity of adsorbed rhBMP-2 and the BMP-induced Smad signaling were investigated with C2C12 model cells. A noticeably high mass-uptake of rhBMP-2 and enhanced recognition of BMPR-IA to adsorbed rhBMP-2 were found on the HAP-Pol surface. For the rhBMP-2-adsorbed HAPs, both ALP activity and Smad signaling increased in the order of HAP-Sinuses of rhBMP-2 in clinical applications and arouse broad interests among researchers in the fields of nano-biotechnology, biomaterials and bone tissue engineering. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Morphology-Variable Aggregates Prepared from Cholesterol-Containing Amphiphilic Glycopolymers: Their Protein Recognition/Adsorption and Drug Delivery Applications

    Directory of Open Access Journals (Sweden)

    Zhao Wang

    2018-02-01

    Full Text Available In this study, a series of diblock glycopolymers, poly(6-O-methacryloyl-d-galactopyranose-b-poly(6-cholesteryloxyhexyl methacrylate (PMAgala-b-PMAChols, with cholesterol/galactose grafts were prepared through a sequential reversible addition-fragmentation chain transfer (RAFT polymerization and deprotection process. The glycopolymers could self-assemble into aggregates with various morphologies depending on cholesterol/galactose-containing block weight ratios, as determined by transmission electronic microscopy (TEM and dynamic laser light scattering (DLS. In addition, the lectin (Ricinus communis agglutinin II, RCA120 recognition and bovine serum albumin (BSA adsorption of the PMAgala-b-PMAChol aggregates were evaluated. The SK-Hep-1 tumor cell inhibition properties of the PMAgala-b-PMAChol/doxorubicin (DOX complex aggregates were further examined in vitro. Results indicate that the PMAgala-b-PMAChol aggregates with various morphologies showed different interaction/recognition features with RCA120 and BSA. Spherical aggregates (d ≈ 92 nm possessed the highest RCA120 recognition ability and lowest BSA protein adsorption. In addition, the DOX-loaded spherical complex aggregates exhibited a better tumor cell inhibition property than those of nanofibrous complex aggregates. The morphology-variable aggregates derived from the amphiphilic glycopolymers may serve as multifunctional biomaterials with biomolecular recognition and drug delivery features.

  10. Preparation of polymethacrylic acid-grafted HEMA/PVP microspheres and preliminary study on basic protein adsorption.

    Science.gov (United States)

    Gao, Baojiao; Hu, Hongyan; Guo, Jianfeng; Li, Yanbin

    2010-06-01

    The crosslinked copolymeric microspheres (HEMA/NVP) of N-vinylpyrrolidone (NVP) and 2-hydroxyethyl methacrylate (HEMA) were prepared using inverse suspension polymerization method. Subsequently, the reaction of methacryloyl chloride with the hydroxyl groups on the surfaces of HEMA/NVP microspheres was performed, leading to the introduction of polymerisable double bonds onto the surfaces of microspheres HEMA/NVP. Afterward, methacrylic acid was allowed to be graft-polymerized on microspheres HEMA/NVP in the manner of "grafting from", resulting in the grafted microspheres PMAA-HEMA/NVP. The grafted microspheres PMAA-HEMA/NVP were fully characterized with several means. The graft-polymerization of MAA on microspheres HEMA/NVP was studied in detail, and the optimal reaction conditions were determined. Thereafter, the adsorption property of the grafted microspheres PMAA-HEMA/NVP for lysozyme as a basic protein model was preliminarily examined to explore the feasibility of removing deleterious basic protein such as density lipoprotein from blood. The experimental results indicate that the PMAA grafting degree on microspheres HEMA/NVP is limited because an enwinding polymer layer as a kinetic barrier on the surfaces of HEMA/NVP microspheres will be formed during the graft-polymerization, and block the graft-polymerization. In order to enhance PMAA grafting degree, reaction temperature, monomer concentration and the used amount of initiator should be effectively controlled. The experimental results also reveal that the grafted microspheres PMAA-HEMA/NVP possess very strong adsorption ability for lysozyme by right of strong electrostatic interaction. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Adsorption of ammonium and phosphate by feather protein based semi-interpenetrating polymer networks hydrogel as a controlled-release fertilizer.

    Science.gov (United States)

    Su, Yuan; Liu, Jia; Yue, Qinyan; Li, Qian; Gao, Baoyu

    2014-01-01

    A new feather protein-grafted poly(potassium acrylate)/polyvinyl alcohol (FP-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was produced through graft copolymerization with FP as a basic macromolecular skeletal material, acrylic acid as a monomer and PVA as a semi-IPNs polymer. The adsorption of ammonium and phosphate ions from aqueous solution using the new hydrogel as N and P controlled-release fertilizer with water-retention capacity was studied. The effects of pH value, concentration, contact time and ion strength on NH4+ and PO3-4 removal by FP-g-PKA/PVA semi-IPNs hydrogel were investigated using batch adsorption experiments. The results indicated that the hydrogel had high adsorption capacities and fast adsorption rates for NH4+ and PO3-4 in wide pH levels ranging from 4.0 to 9.0. Kinetic analysis presented that both NH4+ and PO3-4 removal were closely fitted with the pseudo-second-order model. Furthermore, the adsorption isotherms of hydrogel were best represented by the Freundlich model. The adsorption-desorption experimental results showed the sustainable stability of FP-g-PKA/PVA semi-IPNs hydrogel for NH4+ and PO3-4 removal. Overall, FP-g-PKA/PVA could be considered as an efficient material for the removal and recovery of nitrogen and phosphorus with the agronomic reuse as a fertilizer.

  12. Effect of protein adsorption on the corrosion behavior of 70Cu-30Ni alloy in artificial seawater.

    Science.gov (United States)

    Torres Bautista, Blanca E; Carvalho, Maria L; Seyeux, Antoine; Zanna, Sandrine; Cristiani, Pierangela; Tribollet, Bernard; Marcus, Philippe; Frateur, Isabelle

    2014-06-01

    Copper alloys often used in cooling circuits of industrial plants can be affected by biocorrosion induced by biofilm formation. The objective of this work was to study the influence of protein adsorption, which is the first step in biofilm formation, on the electrochemical behavior of 70Cu-30Ni (wt.%) alloy in static artificial seawater and on the chemical composition of oxide layers. For that purpose, electrochemical measurements performed after 1h of immersion were combined to surface analyses. A model is proposed to analyze impedance data. In the presence of bovine serum albumin (BSA, model protein), the anodic charge transfer resistance deduced from EIS data at Ecorr is slightly higher, corresponding to lower corrosion current. Without BSA, two oxidized layers are shown by XPS and ToF-SIMS: an outer layer mainly composed of copper oxide (Cu2O redeposited layer) and an inner layer mainly composed of oxidized nickel, with a global thickness of ~30nm. The presence of BSA leads to a mixed oxide layer (CuO, Cu2O, Ni(OH)2) with a lower thickness (~10nm). Thus, the protein induces a decrease of the dissolution rate at Ecorr and hence a decrease of the amount of redeposited Cu2O and of the oxide layer thickness. © 2013.

  13. Blocking rapid ice crystal growth through nonbasal plane adsorption of antifreeze proteins

    NARCIS (Netherlands)

    Olijve, L.L.C.; Meister, K.; DeVries, A.L.; Duman, J.G.; Guo, S.; Bakker, H.J.; Voets, I.K.

    2016-01-01

    Antifreeze proteins (AFPs) are a unique class of proteins that bind to growing ice crystal surfaces and arrest further ice growth. AFPs have gained a large interest for their use in antifreeze formulations for water-based materials, such as foods, waterborne paints, and organ transplants. Instead of

  14. Chromatographic and traditional albumin isotherms on cellulose: a model for wound protein adsorption on modified cotton

    Science.gov (United States)

    Albumin is the most abundant protein found in healing wounds. Traditional and chromatogrpahic protein isotherms of albumin binding on modified cotton fibers are useful in understanding albumin binding to cellulose wound dressings. An important consideration in the design of cellulosic wound dressin...

  15. Stainless steel modified with poly(ethylene glycol) can prevent protein adsorption but not bacterial adhesion

    DEFF Research Database (Denmark)

    Wei, Jiang; Bagge, Dorthe; Gram, Lone

    2003-01-01

    and stability of the final PEG layer was examined. Piranha solution proved to be the most effective method for removing adventitious hydrocarbon contamination, compared to cleaning with ultrasonication in organic solvents, and was the SS substrate that produced the most stable and thickest PEI layer...

  16. Volumetric interpretation of protein adsorption: interfacial packing of protein adsorbed to hydrophobic surfaces from surface-saturating solution concentrations.

    Science.gov (United States)

    Kao, Ping; Parhi, Purnendu; Krishnan, Anandi; Noh, Hyeran; Haider, Waseem; Tadigadapa, Srinivas; Allara, David L; Vogler, Erwin A

    2011-02-01

    The maximum capacity of a hydrophobic adsorbent is interpreted in terms of square or hexagonal (cubic and face-centered-cubic, FCC) interfacial packing models of adsorbed blood proteins in a way that accommodates experimental measurements by the solution-depletion method and quartz-crystal-microbalance (QCM) for the human proteins serum albumin (HSA, 66 kDa), immunoglobulin G (IgG, 160 kDa), fibrinogen (Fib, 341 kDa), and immunoglobulin M (IgM, 1000 kDa). A simple analysis shows that adsorbent capacity is capped by a fixed mass/volume (e.g. mg/mL) surface-region (interphase) concentration and not molar concentration. Nearly analytical agreement between the packing models and experiment suggests that, at surface saturation, above-mentioned proteins assemble within the interphase in a manner that approximates a well-ordered array. HSA saturates a hydrophobic adsorbent with the equivalent of a single square or hexagonally-packed layer of hydrated molecules whereas the larger proteins occupy two-or-more layers, depending on the specific protein under consideration and analytical method used to measure adsorbate mass (solution depletion or QCM). Square or hexagonal (cubic and FCC) packing models cannot be clearly distinguished by comparison to experimental data. QCM measurement of adsorbent capacity is shown to be significantly different than that measured by solution depletion for similar hydrophobic adsorbents. The underlying reason is traced to the fact that QCM measures contribution of both core protein, water of hydration, and interphase water whereas solution depletion measures only the contribution of core protein. It is further shown that thickness of the interphase directly measured by QCM systematically exceeds that inferred from solution-depletion measurements, presumably because the static model used to interpret solution depletion does not accurately capture the complexities of the viscoelastic interfacial environment probed by QCM. Copyright © 2010

  17. Extracting Tenebrio molitor protein while preventing browning: effect of pH and NaCl on protein yield

    NARCIS (Netherlands)

    Yi, L.; Boekel, van T.; Lakemond, C.M.M.

    2017-01-01

    The potential of insects as an alternative protein source for food applications was investigated by studying the effect of pH and NaCl on extraction yield of water-soluble proteins from Tenebrio molitor, while preventing browning due to polyphenol oxidation. Minimum protein solubility (29.6%) was at

  18. MRI-compatible Nb–60Ta–2Zr alloy used for vascular stents: Haemocompatibility and its correlation with protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiu-Mei [School of Stomatology, China Medical University, 117 Nanjing North Street, Shenyang 110002 (China); Li, Hui-Zhe; Wang, Shao-Ping [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Huang, Hsun-Miao; Huang, Her-Hsiung [Biomaterials and Electrochemistry Lab, Department of Dentistry, National Yang-Ming University, Taipei City 112, Taiwan (China); Ai, Hong-Jun, E-mail: aih0620@yahoo.com.cn [School of Stomatology, China Medical University, 117 Nanjing North Street, Shenyang 110002 (China); Xu, Jian, E-mail: jianxu@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2014-09-01

    Nb–60Ta–2Zr is a newly developed MRI-compatible alloy used for vascular stents. In this work, its haemocompatibility was investigated, including platelet adhesion (lactate dehydrogenase activity), platelet activation (P-selectin expression), coagulation and haemolysis. For comparison, parallel assessments for these factors were performed for the niobium, tantalum, 316L stainless steel (316L SS) and L605 Co–Cr alloy (L605). In addition, albumin and fibrinogen were selected to examine the correlation of protein adsorption with platelet adhesion and metal surface properties. The propensity for platelet adhesion and activation on the Nb–60Ta–2Zr alloy was at nearly the same level as that for Nb and Ta but was slightly less than those of 316L SS and L605. The mitigated platelet adhesion and activation of the Nb–60Ta–2Zr alloy is associated with its decreased adsorption of fibrinogen. The Nb–60Ta–2Zr alloy has a longer clotting time and exhibits significantly superior thromboresistance than 316L SS and L605. Moreover, the haemolysis rate of the Nb–60Ta–2Zr alloy satisfies the bio-safety requirement of the ISO 10993–4 standard. The favourable haemocompatiblity of the Nb–60Ta–2Zr alloy provides evidence of its good biocompatibility and of its suitability as a candidate stent material. - Highlights: • The Nb–60Ta–2Zr alloy is less hydrophobic than the 316L SS and L605 alloy. • The Nb–60Ta–2Zr has slightly weak propensity for platelet adhesion and activation. • The Nb–60Ta–2Zr alloy results in a longer clotting time. • Haemolysis of Nb–60Ta–2Zr is slightly lower than that of 316L SS and L605. • The Nb–60Ta–2Zr alloy is a promising MRI-compatible stent material.

  19. Characteristics of selective fluoride adsorption by biocarbon-Mg/Al layered double hydroxides composites from protein solutions: kinetics and equilibrium isotherms study.

    Science.gov (United States)

    Ma, Wei; Lv, Tengfei; Song, Xiaoyan; Cheng, Zihong; Duan, Shibo; Xin, Gang; Liu, Fujun; Pan, Decong

    2014-03-15

    In the study, two novel applied biocarbon-Mg/Al layered double hydroxides composites (CPLDH and CPLDH-Ca) were successfully prepared and characterized by TEM, ICP-AES, XFS, EDS, FTIR, XRD, BET and pHpzc. The fluoride removal efficiency (RF) and protein recovery ratio (RP) of the adsorbents were studied in protein systems of lysozyme (LSZ) and bovine serum albumin (BSA). The results showed that the CPLDH-Ca presented remarkable performance for selective fluoride removal from protein solution. It reached the maximum RF of 92.1% and 94.8% at the CPLDH-Ca dose of 2.0g/L in LSZ and BSA system, respectively. The RP in both systems of LSZ and BSA were more than 90%. Additionally, the RP of CPLDH-Ca increased with the increase of ionic strengths, and it almost can be 100% with more than 93% RF. Fluoride adsorption by the CPLDH-Ca with different initial fluoride concentrations was found to obey the mixed surface reaction and diffusion controlled adsorption kinetic model, and the overall reaction rate is probably controlled by intra-particle diffusion, boundary layer diffusion and reaction process. The adsorption isotherms of fluoride in BSA system fit the Langmuir-Freundlich model well. The BSA has synergistic effect on fluoride adsorption and the degree increased with the increase of the initial BSA concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Calcium phosphate–gold nanoparticles nanocomposite for protein adsorption and mediator-free H2O2 biosensor construction

    International Nuclear Information System (INIS)

    Xu Qin; Lu Guiju; Bian XiaoJun; Jin Gendi; Wang Wei; Hu Xiaoya; Wang Yang; Yang Zhanjun

    2012-01-01

    This work reports a new method for the preparation and application of a kind of biocompatible calcium phosphate–gold nanoparticles (Ca 3 (PO 4 ) 2 –AuNPs) nanocomposite. UV–vis spectroscopy and transmittance electron microscopy (TEM) have been used to monitor the formation process of the nanocomposite and to examine the interaction between calcium phosphate and gold nanoparticles (AuNPs). The nanocomposite has multiple sites and improved conductivity which make it suitable for the binding of proteins to construct electrochemical sensors. Myoglobin (Mb) adsorbed on the nanocomposite retained its native structure which was proved by Fourier transform infrared spectroscopy (FTIR). Direct electron transfer between the adsorbed Mb and the electrode was observed. Further results demonstrated that the adsorbed Mb has good electrocatalytic activity towards the reduction of H 2 O 2 in the absence of any mediator. Highlights: ► Using gelatin modified gold nanoparticles to prepare needle-like calcium phosphate. ► Calcium phosphate provides multiple sites for protein adsorption. ► Gold nanoparticles act as electron tunneling. ► Myoglobin adsorbed on the material showed direct electrochemistry and good catalysis.

  1. Laser- and UV-assisted modification of polystyrene surfaces for control of protein adsorption and cell adhesion

    International Nuclear Information System (INIS)

    Pfleging, Wilhelm; Torge, Maika; Bruns, Michael; Trouillet, Vanessa; Welle, Alexander; Wilson, Sandra

    2009-01-01

    An appropriate choice of laser and process parameters enables new approaches for the fabrication of polymeric lab-on-chip devices with integrated functionalities. We will present our current research results in laser-assisted modification of polystyrene (PS) with respect to the fabrication of polymer devices for cell culture applications. For this purpose laser micro-patterning of PS and subsequent surface functionalization was investigated as function of laser and process parameters. A high power ArF-excimer laser radiation source with a pulse length of 19 ns as well as a high repetition ArF-excimer laser source with a pulse length of 5 ns were used in order to study the influence of laser pulse length on laser-induced surface oxidation. The change in surface chemistry was characterized by X-ray photoelectron spectroscopy and contact angle measurements. The difference between laser-assisted modification versus UV-lamp assisted modification was investigated. A photolytic activation of specific areas of the polymer surface and subsequent oxidization in oxygen or ambient air leads to a chemically modified polymer surface bearing carboxylic acid groups well-suited for controlled competitive protein adsorption or protein immobilization. Finally, distinct areas for cell growth and adhesion are obtained

  2. Driving force behind adsorption-induced protein unfolding: a time-resolved X-ray reflectivity study on lysozyme adsorbed at an air/water interface.

    Science.gov (United States)

    Yano, Yohko F; Uruga, Tomoya; Tanida, Hajime; Toyokawa, Hidenori; Terada, Yasuko; Takagaki, Masafumi; Yamada, Hironari

    2009-01-06

    Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.

  3. Nanoparticle Surface Specific Adsorption of Zein and Its Self-assembled Behavior of Nanocubes Formation in Relation to On-Off SERS: Understanding Morphology Control of Protein Aggregates.

    Science.gov (United States)

    Navdeep; Banipal, Tarlok Singh; Kaur, Gurinder; Bakshi, Mandeep Singh

    2016-01-27

    Zein, an industrially important protein, is characterized in terms of its food and pharmaceutical coating applications by using surface enhanced Raman spectroscopy (SERS) on Au, Ag, and PbS nanoparticles (NPs). Its specific surface adsorption behavior on Ag NPs produced self-assembled zein nanocubes which demonstrated on and off SERS activity. Both SERS characterization as well as nanocube formation of zein helped us to understand the complex protein aggregation behavior in shape controlled morphologies, a process with significant ramifications in protein crystallization to achieve ordered morphologies. Interestingly, nanocube formation was promoted in the presence of Ag rather than Au or PbS NPs under in situ synthesis and discussed in terms of specific adsorption. Zein fingerprinting was much more clear and enhanced on Au surface in comparison to Ag while PbS did not demonstrate SERS due to its semiconducting nature.

  4. An Experimental Approach to Controllably Vary Protein Oxidation While Minimizing Electrode Adsorption for Boron-Doped Diamond Electrochemical Surface Mapping Applications

    Science.gov (United States)

    McClintock, Carlee S; Hettich, Robert L.

    2012-01-01

    Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent – hydroxyl radicals – for these measurements; however, these approaches range significantly in their complexity and expense of operation. This research expands upon earlier work to enhance the controllability of boron-doped diamond (BDD) electrochemistry as an easily accessible tool for producing hydroxyl radicals in order to oxidize a range of intact proteins. Efforts to modulate oxidation level while minimizing the adsorption of protein to the electrode involved the use of relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber. Additionally, a different cell activation approach using variable voltage to supply a controlled current allowed us to precisely tune the extent of oxidation in a protein-dependent manner. In order to gain perspective on the level of protein adsorption onto the electrode surface, studies were conducted to monitor protein concentration during electrolysis and gauge changes in the electrode surface between cell activation events. This report demonstrates the successful use of BDD electrochemistry for greater precision in generating a target number of oxidation events upon intact proteins. PMID:23210708

  5. In vitro haematic proteins adsorption and cytocompatibility study on acrylic copolymer to realise coatings for drug-eluting stents

    International Nuclear Information System (INIS)

    Gagliardi, Mariacristina

    2012-01-01

    In the present paper, a preliminary in vitro analysis of biocompatibility of newly-synthesised acrylic copolymers is reported. In particular, with the aim to obtain coatings for drug-eluting stents, blood protein absorption and cytocompatibility were studied. For protein absorption tests, bovine serum albumin and bovine plasma fibrinogen were considered. Cytocompatibility was tested using C2C12 cell line as model, analysing the behaviour of polymeric matrices and of drug-eluting systems, obtained loading polymeric matrices with paclitaxel, an anti-mitotic drug, in order to evaluate the efficacy of a pharmacological treatment locally administered from these materials. Results showed that the amount of albumin absorbed was greater than the amount of fibrinogen (comprised in the range of 70%–85% and 10%–22% respectively) and it is a good behaviour in terms of haemocompatibility. Cell culture tests showed good adhesion properties and a relative poor proliferation. In addition, a strong effect related to drug elution and a correlation with the macromolecular composition were detected. In this preliminary analysis, tested materials showed good characteristics and can be considered possible candidates to obtain coatings for drug-eluting stents. Highlights: ► Preliminary evaluation of haemo- and cytocompatibility of newly-synthesised acrylic copolymers ► Materials adsorb higher amounts of albumin and with a faster rate than fibrinogen. ► Protein adsorption depended on the macromolecular composition and surface properties. ► Cell viability on pure samples and efficacy of paclitaxel release were verified in C2C12 cultures.

  6. In vitro haematic proteins adsorption and cytocompatibility study on acrylic copolymer to realise coatings for drug-eluting stents

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Mariacristina, E-mail: mariacristina.gagliardi@iit.it

    2012-12-01

    In the present paper, a preliminary in vitro analysis of biocompatibility of newly-synthesised acrylic copolymers is reported. In particular, with the aim to obtain coatings for drug-eluting stents, blood protein absorption and cytocompatibility were studied. For protein absorption tests, bovine serum albumin and bovine plasma fibrinogen were considered. Cytocompatibility was tested using C2C12 cell line as model, analysing the behaviour of polymeric matrices and of drug-eluting systems, obtained loading polymeric matrices with paclitaxel, an anti-mitotic drug, in order to evaluate the efficacy of a pharmacological treatment locally administered from these materials. Results showed that the amount of albumin absorbed was greater than the amount of fibrinogen (comprised in the range of 70%-85% and 10%-22% respectively) and it is a good behaviour in terms of haemocompatibility. Cell culture tests showed good adhesion properties and a relative poor proliferation. In addition, a strong effect related to drug elution and a correlation with the macromolecular composition were detected. In this preliminary analysis, tested materials showed good characteristics and can be considered possible candidates to obtain coatings for drug-eluting stents. Highlights: Black-Right-Pointing-Pointer Preliminary evaluation of haemo- and cytocompatibility of newly-synthesised acrylic copolymers Black-Right-Pointing-Pointer Materials adsorb higher amounts of albumin and with a faster rate than fibrinogen. Black-Right-Pointing-Pointer Protein adsorption depended on the macromolecular composition and surface properties. Black-Right-Pointing-Pointer Cell viability on pure samples and efficacy of paclitaxel release were verified in C2C12 cultures.

  7. Gamete therapeutics: recombinant protein adsorption by sperm for increasing fertility via artificial insemination.

    Science.gov (United States)

    Alvarez-Gallardo, Horacio; Kjelland, Michael E; Moreno, Juan F; Welsh, Thomas H; Randel, Ronald D; Lammoglia, Miguel A; Pérez-Martínez, Mario; Lara-Sagahón, Alma V; Esperón-Sumano, A Enrique; Romo, Salvador

    2013-01-01

    A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system's response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented.

  8. Gamete therapeutics: recombinant protein adsorption by sperm for increasing fertility via artificial insemination.

    Directory of Open Access Journals (Sweden)

    Horacio Alvarez-Gallardo

    Full Text Available A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs, specifically the fertility associated antigen (FAA and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2, act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system's response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA and recombinant TIMP-2 (rTIMP-2 to bovine semen before cryopreservation for use in an artificial insemination (AI program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus heifers were selected based on their estrus cycle, body condition score (BCS, of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal measurements. Heifers were synchronized using estradiol benzoate (EB, Celosil® (PGF2α (Shering-Plough and a controlled internal drug release (CIDR device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL and rTIMP-2 (25 µg/mL. In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037. Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented.

  9. The Effect of Simulated Microgravity Environment of RWV Bioreactors on Surface Reactions and Adsorption of Serum Proteins on Bone-bioactive Microcarriers

    Science.gov (United States)

    Radin, Shula; Ducheyne, P.; Ayyaswamy, P. S.

    2003-01-01

    Biomimetically modified bioactive materials with bone-like surface properties are attractive candidates for use as microcarriers for 3-D bone-like tissue engineering under simulated microgravity conditions of NASA designed rotating wall vessel (RWV) bioreactors. The simulated microgravity environment is attainable under suitable parametric conditions of the RWV bioreactors. Ca-P containing bioactive glass (BG), whose stimulatory effect on bone cell function had been previously demonstrated, was used in the present study. BG surface modification via reactions in solution, resulting formation of bone-like minerals at the surface and adsorption of serum proteins is critical for obtaining the stimulatory effect. In this paper, we report on the major effects of simulated microgravity conditions of the RWV on the BG reactions surface reactions and protein adsorption in physiological solutions. Control tests at normal gravity were conducted at static and dynamic conditions. The study revealed that simulated microgravity remarkably enhanced reactions involved in the BG surface modification, including BG dissolution, formation of bone-like minerals at the surface and adsorption of serum proteins. Simultaneously, numerical models were developed to simulate the mass transport of chemical species to and from the BG surface under normal gravity and simulated microgravity conditions. The numerical results showed an excellent agreement with the experimental data at both testing conditions.

  10. Interactions between protein molecules and the virus removal membrane surface: Effects of immunoglobulin G adsorption and conformational changes on filter performance.

    Science.gov (United States)

    Hamamoto, Ryo; Ito, Hidemi; Hirohara, Makoto; Chang, Ryongsok; Hongo-Hirasaki, Tomoko; Hayashi, Tomohiro

    2018-03-01

    Membrane fouling commonly occurs in all filter types during virus filtration in protein-based biopharmaceutical manufacturing. Mechanisms of decline in virus filter performance due to membrane fouling were investigated using a cellulose-based virus filter as a model membrane. Filter performance was critically dependent on solution conditions; specifically, ionic strength. To understand the interaction between immunoglobulin G (IgG) and cellulose, sensors coated with cellulose were fabricated for surface plasmon resonance and quartz crystal microbalance with energy dissipation measurements. The primary cause of flux decline appeared to be irreversible IgG adsorption on the surface of the virus filter membrane. In particular, post-adsorption conformational changes in the IgG molecules promoted further irreversible IgG adsorption, a finding that could not be adequately explained by DLVO theory. Analyses of adsorption and desorption and conformational changes in IgG molecules on cellulose surfaces mimicking cellulose-based virus removal membranes provide an effective approach for identifying ways of optimizing solution conditions to maximize virus filter performance. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:379-386, 2018. © 2017 American Institute of Chemical Engineers.

  11. Mechanism underlying bioinertness of self-assembled monolayers of oligo(ethyleneglycol)-terminated alkanethiols on gold: protein adsorption, platelet adhesion, and surface forces.

    Science.gov (United States)

    Hayashi, Tomohiro; Tanaka, Yusaku; Koide, Yuki; Tanaka, Masaru; Hara, Masahiko

    2012-08-07

    The mechanism underlying the bioinertness of the self-assembled monolayers of oligo(ethylene glycol)-terminated alkanethiol (OEG-SAM) was investigated with protein adsorption experiments, platelet adhesion tests, and surface force measurements with an atomic force microscope (AFM). In this work, we performed systematic analysis with SAMs having various terminal groups (-OEG, -OH, -COOH, -NH(2), and -CH(3)). The results of the protein adsorption experiment by the quartz crystal microbalance (QCM) method suggested that having one EG unit and the neutrality of total charges of the terminal groups are essential for protein-resistance. In particular, QCM with energy dissipation analyses indicated that proteins absorb onto the OEG-SAM via a very weak interaction compared with other SAMs. Contrary to the protein resistance, at least three EG units as well as the charge neutrality of the SAM are found to be required for anti-platelet adhesion. When the identical SAMs were formed on both AFM probe and substrate, our force measurements revealed that only the OEG-SAMs possessing more than two EG units showed strong repulsion in the range of 4 to 6 nm. In addition, we found that the SAMs with other terminal groups did not exhibit such repulsion. The repulsion between OEG-SAMs was always observed independent of solution conditions [NaCl concentration (between 0 and 1 M) and pH (between 3 and 11)] and was not observed in solution mixed with ethanol, which disrupts the three-dimensional network of the water molecules. We therefore concluded that the repulsion originated from structured interfacial water molecules. Considering the correlation between the above results, we propose that the layer of the structured interfacial water with a thickness of 2 to 3 nm (half of the range of the repulsion observed in the surface force measurements) plays an important role in deterring proteins and platelets from adsorption or adhesion.

  12. Dietary Protein in the Prevention of Diet-Induced Obesity and Co-Morbidities

    DEFF Research Database (Denmark)

    Tastesen, Hanne Sørup

    mice were fed obesity‐promoting diets with protein from different sources, in different forms and at different levels to evaluate the affect on development of obesity, glucose intolerance and dyslipidemia. Results: In the present study the dietary level of protein, 16 versus 32 percent energy from...... protein, was found to be negligible in development of obesity and co‐morbidities in mice. Seafood protein with high endogenous taurine and glycine contents was found to prevent diet‐induced adiposity and dyslipidemia, both in ad libitum and pair‐fed settings. The ability of seafood proteins to prevent...... that the source and form of protein has great impact on development and prevention of diet‐induced adiposity, dyslipidemia, hyperinsulinemia and impairment of glucose tolerance through modulations of voluntary locomotor activity, energy expenditure and energy substrate metabolism in mice...

  13. Protein Corona Prevents TiO2 Phototoxicity.

    Directory of Open Access Journals (Sweden)

    Maja Garvas

    Full Text Available TiO2 nanoparticles have generally low toxicity in the in vitro systems although some toxicity is expected to originate in the TiO2-associated photo-generated radical production, which can however be modulated by the radical trapping ability of the serum proteins. To explore the role of serum proteins in the phototoxicity of the TiO2 nanoparticles we measure viability of the exposed cells depending on the nanoparticle and serum protein concentrations.Fluorescence and spin trapping EPR spectroscopy reveal that the ratio between the nanoparticle and protein concentrations determines the amount of the nanoparticles' surface which is not covered by the serum proteins and is proportional to the amount of photo-induced radicals. Phototoxicity thus becomes substantial only at the protein concentration being too low to completely coat the nanotubes' surface.These results imply that TiO2 nanoparticles should be applied with ligands such as proteins when phototoxic effects are not desired - for example in cosmetics industry. On the other hand, the nanoparticles should be used in serum free medium or any other ligand free medium, when phototoxic effects are desired - as for efficient photodynamic cancer therapy.

  14. Effects of atomic-level nano-structured hydroxyapatite on adsorption of bone morphogenetic protein-7 and its derived peptide by computer simulation.

    Science.gov (United States)

    Wang, Qun; Wang, Menghao; Lu, Xiong; Wang, Kefeng; Fang, Liming; Ren, Fuzeng; Lu, Guoming

    2017-11-09

    Hydroxyapatite (HA) is the principal inorganic component of bones and teeth and has been widely used as a bone repair material because of its good biocompatibility and bioactivity. Understanding the interactions between proteins and HA is crucial for designing biomaterials for bone regeneration. In this study, we evaluated the effects of atomic-level nano-structured HA (110) surfaces on the adsorption of bone morphogenetic protein-7 (BMP-7) and its derived peptide (KQLNALSVLYFDD) using molecular dynamics and density functional theory methods. The results indicated that the atomic-level morphology of HA significantly affected the interaction strength between proteins and HA substrates. The interactions of BMP-7 and its derived peptide with nano-concave and nano-pillar HA surfaces were stronger than those with flat or nano-groove HA surfaces. The results also revealed that if the groove size of nano-structured HA surfaces matched that of residues in the protein or peptide, these residues were likely to spread into the grooves of the nano-groove, nano-concave, and nano-pillar HA, further strengthening the interactions. These results are helpful in better understanding the adsorption behaviors of proteins onto nano-structured HA surfaces, and provide theoretical guidance for designing novel bioceramic materials for bone regeneration and tissue engineering.

  15. Chemistry and stability of thiol based polyethylene glycol surface coatings on colloidal gold and their relationship to protein adsorption and clearance in vivo

    Science.gov (United States)

    Carpinone, Paul

    Nanomaterials have presented a wide range of novel biomedical applications, with particular emphasis placed on advances in imaging and treatment delivery. Of the many particulate nanomaterials researched for biomedical applications, gold is one of the most widely used. Colloidal gold has been of great interest due to its chemical inertness and its ability to perform multiple functions, such as drug delivery, localized heating of tissues (hyperthermia), and imaging (as a contrast agent). It is also readily functionalized through the use of thiols, which spontaneously form sulfur to gold bonds with the surface. Polyethylene glycol (PEG) is the most widely used coating material for these particles as it provides both steric stability to the suspension and protein resistance. These properties extend the circulation time of the particles in blood, and consequently the efficacy of the treatment. Despite widespread use of PEG coated gold particles, the coating chemistry and stability of these particles are largely unknown. The goal of this work was to identify the mechanisms leading to degradation and stability of thiol based polyethylene glycol coatings on gold particles and to relate this behavior to protein adsorption and clearance in vivo. The results indicate that the protective PEG coating is susceptible to sources of oxidation (including dissolved oxygen) and competing adsorbates, among other factors. The quality of commercially available thiolated PEG reagents was also found to play a key role in the quality and protein resistance of the final PEG coating. Analysis of the stability of these coatings indicated that they rapidly degrade under physiological conditions, leading to the onset of protein adsorption when exposed to plasma or blood. Paralleling the protein adsorption behavior and onset of coating degradation observed in vitro, blood clearance of parenterally administered PEG coated particles in mice began after approximately 2h of circulation time. Taken

  16. BSA Nanoparticles for siRNA Delivery: Coating Effects on Nanoparticle Properties, Plasma Protein Adsorption, and In Vitro siRNA Delivery

    Directory of Open Access Journals (Sweden)

    Haran Yogasundaram

    2012-01-01

    Full Text Available Developing vehicles for the delivery of therapeutic molecules, like siRNA, is an area of active research. Nanoparticles composed of bovine serum albumin, stabilized via the adsorption of poly-L-lysine (PLL, have been shown to be potentially inert drug-delivery vehicles. With the primary goal of reducing nonspecific protein adsorption, the effect of using comb-type structures of poly(ethylene glycol (1 kDa, PEG units conjugated to PLL (4.2 and 24 kDa on BSA-NP properties, apparent siRNA release rate, cell viability, and cell uptake were evaluated. PEGylated PLL coatings resulted in NPs with ζ-potentials close to neutral. Incubation with platelet-poor plasma showed the composition of the adsorbed proteome was similar for all systems. siRNA was effectively encapsulated and released in a sustained manner from all NPs. With 4.2 kDa PLL, cellular uptake was not affected by the presence of PEG, but PEG coating inhibited uptake with 24 kDa PLL NPs. Moreover, 24 kDa PLL systems were cytotoxic and this cytotoxicity was diminished upon PEG incorporation. The overall results identified a BSA-NP coating structure that provided effective siRNA encapsulation while reducing ζ-potential, protein adsorption, and cytotoxicity, necessary attributes for in vivo application of drug-delivery vehicles.

  17. Using X-PEEM to study biomaterials: Protein and peptide adsorption to a polystyrene-poly(methyl methacrylate)-b-polyacrylic acid blend

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Bonnie O. [Chemistry and Chemical Biology, BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1 (Canada); Hitchcock, Adam P., E-mail: aph@mcmaster.ca [Chemistry and Chemical Biology, BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1 (Canada); Cornelius, Rena M.; Brash, John L. [School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4M1 (Canada); Scholl, Andreas; Doran, Andrew [Advanced Light Source, Berkeley Lab, Berkeley, CA 94720 (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We review applications of synchrotron X-PEEM to biomaterials. Black-Right-Pointing-Pointer We report characterization of a PS/PMMA-b-PAA blend surface by AFM and X-PEEM. Black-Right-Pointing-Pointer We report quantitative mapping of protein (HSA) and peptide adsorption on PS/PMMA-b-PAA. Black-Right-Pointing-Pointer We report how this adsorption changes with pH. -- Abstract: Recent synchrotron-based soft X-ray photoemission electron microscopy (X-PEEM) studies of protein and peptide interaction with phase segregated and patterned polymer surfaces in the context of optimization of candidate biomaterials are reviewed and a study of a new system is reported. X-PEEM and atomic force microscopy (AFM) were used to investigate the morphology of a phase-segregated thin film of a polystyrene/poly(methyl methacrylate)-b-polyacrylic acid (PS/PMMA-PAA) blend, and its interactions with negatively charged human serum albumin (HSA) and positively charged SUB-6 (a cationic antimicrobial peptide, RWWKIWVIRWWR-NH{sub 2}) at several pHs. At neutral pH, where the polymer surface is partially negatively charged, HSA and SUB-6 peptide showed contrasting adsorption behavior which is interpreted in terms of differences in their electrostatic interactions with the polymer surface.

  18. Adsorption of lysozyme unto silica and polystyrene surfaces in ...

    African Journals Online (AJOL)

    user

    2011-04-11

    Apr 11, 2011 ... surfaces were well fitted by the Langmuir adsorption isotherm model with maximum adsorption .... following reasons: (1) Lysozyme is a globular protein with ... vigorously for 1 h to attain equilibrium adsorption and allowed to.

  19. Analysis of plasma protein adsorption onto DC-Chol-DOPE cationic liposomes by HPLC-CHIP coupled to a Q-TOF mass spectrometer

    KAUST Repository

    Capriotti, Anna Laura; Caracciolo, Giulio; Caruso, Giuseppe; Cavaliere, Chiara; Pozzi, Daniela; Samperi, Roberto; Laganà , Aldo

    2010-01-01

    Plasma protein adsorption is regarded as a key factor in the in vivo organ distribution of intravenously administered drug carriers, and strongly depends on vector surface characteristics. The present study aimed to characterize the "protein corona" absorbed onto DC-Chol-DOPE cationic liposomes. This system was chosen because it is one of the most efficient and widely used non-viral formulations in vitro and a potential candidate for in vivo transfection of genetic material. After incubation of human plasma with cationic liposomes, nanoparticle-protein complex was separated from plasma by centrifugation. An integrated approach based on protein separation by one-dimensional 12% polyacrylamide gel electrophoresis followed by the automated HPLC-Chip technology coupled to a high-resolution mass spectrometer was employed for protein corona characterization. Thirty gel lanes, approximately 2 mm, were cut, digested and analyzed by HPLC-MS/MS. Fifty-eight human plasma proteins adsorbed onto DC-Chol-DOPE cationic liposomes were identified. The knowledge of the interactions of proteins with liposomes can be exploited for future controlled design of colloidal drug carriers and possibly in the controlled creation of biocompatible surfaces of other devices that come into contact with proteins in body fluids. © 2010 Springer-Verlag.

  20. Analysis of plasma protein adsorption onto DC-Chol-DOPE cationic liposomes by HPLC-CHIP coupled to a Q-TOF mass spectrometer

    KAUST Repository

    Capriotti, Anna Laura

    2010-09-22

    Plasma protein adsorption is regarded as a key factor in the in vivo organ distribution of intravenously administered drug carriers, and strongly depends on vector surface characteristics. The present study aimed to characterize the "protein corona" absorbed onto DC-Chol-DOPE cationic liposomes. This system was chosen because it is one of the most efficient and widely used non-viral formulations in vitro and a potential candidate for in vivo transfection of genetic material. After incubation of human plasma with cationic liposomes, nanoparticle-protein complex was separated from plasma by centrifugation. An integrated approach based on protein separation by one-dimensional 12% polyacrylamide gel electrophoresis followed by the automated HPLC-Chip technology coupled to a high-resolution mass spectrometer was employed for protein corona characterization. Thirty gel lanes, approximately 2 mm, were cut, digested and analyzed by HPLC-MS/MS. Fifty-eight human plasma proteins adsorbed onto DC-Chol-DOPE cationic liposomes were identified. The knowledge of the interactions of proteins with liposomes can be exploited for future controlled design of colloidal drug carriers and possibly in the controlled creation of biocompatible surfaces of other devices that come into contact with proteins in body fluids. © 2010 Springer-Verlag.

  1. Real time, high resolution studies of protein adsorption and structure at the solid-liquid interface using dual polarization interferometry

    International Nuclear Information System (INIS)

    Freeman, Neville J; Peel, Louise L; Swann, Marcus J; Cross, Graham H; Reeves, Andrew; Brand, Stuart; Lu, Jian R

    2004-01-01

    A novel method for the analysis of thin biological films, called dual polarization interferometry (DPI), is described. This high resolution (<1 A), laboratory-based technique allows the thickness and refractive index (density) of biological molecules adsorbing or reacting at the solid-liquid interface to be measured in real time (up to 10 measurements per second). Results from the adsorption of bovine serum albumin (BSA) on to a silicon oxynitride chip surface are presented to demonstrate how time dependent molecular behaviour can be examined using DPI. Mechanistic and structural information relating to the adsorption process is obtained as a function of the solution pH

  2. Adsorption of proteins from plasma to a series of hydrophilic-hydrophobic copolymers. I. Analysis with the in situ radioiodination technique

    International Nuclear Information System (INIS)

    Horbett, T.A.; Weathersby, P.K.

    1981-01-01

    The adsorption of proteins affects cellular interactions with foreign surfaces and thus plays an important role in determining the biocompatibility of implants. Previous studies have indicated differences in the affinity of various proteins for a given polymer, and differences in the affinity of fibrinogen for a series of polymers varying in hydrophilicity. These studies suggest that differences in the composition of the protein layer adsorbed to polymers from plasma might exist. To examine this hypothesis, the proteins adsorbed from plasma to a series of polymers varying in hydrophilicity were analyzed with the iodogram technique. Copolymers of hydroxyethyl methacrylate and ethyl methacrylate made by the radiation grafting technique were exposed to plasma for 0.5 or 150 min. The adsorbed proteins were iodinated, eluted with SDS, and separated with polyacrylamide gel electrophoresis. Fibrinogen, immunoglobulin G, hemoglobin, and a peak tentatively ascribed to prothrombin were the major proteins detected. Very little iodine was incorporated into adsorbed albumin, even though it was shown to be present by a separate experiment using dye binding. The fraction of total radioactivity associated with each of nine proteins was found to vary markedly and systematically among the surfaces. The distribution of radioactivity into the proteins was very different on 0.5 and 150-min plasma exposed polymers. The results reflect both compositional differences in the adsorbed protein layer on the polymers and differences in the accessibility of proteins to the labeling reagent in the adsorbed state. Differences in the organization of the adsorbed protein layer may play a key role in determining whether cell surface receptors can come in contact with the specific plasma protein able to further stimulate the cell

  3. Adsorption of Nucleic Acid/Protein Supramolecular Complexes on Goethite: The Influence of Solution Interactions on Behavior at the Solution-Mineral Interface

    Science.gov (United States)

    Schmidt, M.; Martinez, C. E.

    2017-12-01

    Adsorption of biomolecule rich supramolecular complexes onto mineral surfaces plays an important role in the development of organo-mineral associations in soils. In this study, a series of supramolecular complexes of a model nucleic acid (deoxyribonucleic acid (DNA)) and protein (bovine serum albumin (BSA)) are synthesized, characterized and exposed to goethite to probe their adsorption behavior. To synthesize DNA/BSA complexes, a fixed DNA concentration (0.1 mg/mL) was mixed with a range of BSA concentrations (0.025-0.5 mg/mL) in 5 mM KCl at pH=5.0. Circular dichroism spectroscopy demonstrates strong, cooperative, Hill-type binding between DNA and BSA (Ka= 4.74 x 105 M-1) with DNA saturation achieved when BSA concentration reaches 0.4 mg/mL. Dynamic light scattering measurements of DNA/BSA complexes suggest binding accompanies disruption of DNA-DNA intermolecular electrostatic repulsion, resulting in a decrease of the DNA slow relaxation mode with increasing amount of BSA. Zeta potential measurements show increasing amounts of BSA lead to a reduction of negative charge on DNA/BSA complexes, in line with light scattering results. In situ attenuated total reflectance Fourier transform infrared spectroscopic studies of adsorption of DNA/BSA complexes onto goethite show that complexation of BSA with DNA appears to hinder direct coordination of DNA backbone phosphodiester groups with goethite, relative to DNA by itself. Furthermore, increasing amount of BSA (up to 0.4 mg/mL) in DNA/BSA complexes enhances DNA adsorption, possibly as a result of reduced repulsion between adsorbed DNA helices. When BSA concentration exceeds 0.4 mg/mL, a decrease in adsorbed DNA is observed. We hypothesize that this discrepancy in behavior between systems with BSA concentrations below and above saturation of DNA is caused by initial fast adsorption of loosely associated BSA on goethite, restricting access to goethite surface sites. Overall, these results highlight the impact of solution

  4. Toward the treatment for Alzheimer's disease: adsorption is primary mechanism of removing amyloid β protein with hollow-fiber dialyzers of the suitable materials, polysulfone and polymethyl methacrylate.

    Science.gov (United States)

    Kawaguchi, Kazunori; Saigusa, Akira; Yamada, Shinji; Gotoh, Takehiro; Nakai, Shigeru; Hiki, Yoshiyuki; Hasegawa, Midori; Yuzawa, Yukio; Kitaguchi, Nobuya

    2016-06-01

    The accumulation of amyloid β protein (Aβ) in the brain reflects cognitive impairment in Alzheimer's disease. We hypothesized that the rapid removal of Aβ from the blood by an extracorporeal system may act as a peripheral Aβ sink from the brain. The present study aimed to determine the optimal materials and modality for Aβ removal by hemodialyzers. In a batch analysis, hollow-fiber fragments of polysulfone (PSf) and polymethyl methacrylate (PMMA) showed greater removal efficiency of Aβ than did other materials, such as cellulose-triacetates and ethylene-vinyl alcohol copolymer (PSf:PMMA at 30 min, 98.6 ± 2.4 %:97.8 ± 0.4 % for Aβ1-40 and 96.6 ± 0.3 %:99.0 ± 1.0 % for Aβ1-42). In a modality study, the Aβ solution was applied to PSf dialyzers and circulated in the dialysis and Air-filled adsorption-mode (i.e., the outer space of the hollow fibers was filled with air) or phosphate-buffered saline (PBS)-filled adsorption modes. The Aβ1-40 removal efficiency of the pre/post dialyzer in the Air-filled adsorption-mode was the highest (62.4 ± 12.6 %, p = 0.007). In a flow rate study in the Air-filled adsorption-mode, 200 mL/min showed the highest Aβ1-40 reduction rate of pool solution (97.3 ± 0.8 % at 15 min) compared with 20 mL/min (p = 0.00001) and 50 mL/min (p = 0.00382). PMMA dialyzers showed similar high reduction rates. Thus, the optimal modality for Aβ removal was the adsorption-mode with PSf or PMMA hollow fibers at around 50 mL/min flow rate, which seems to be suitable for clinical use.

  5. 生物陶瓷表面蛋白吸附的研究进展%Research progress of protein adsorption on surface of bioceramics

    Institute of Scientific and Technical Information of China (English)

    王传勇

    2012-01-01

    Bioactive ceramics have been widely used in replacing defected hard tissues caused by trauma or disease. When biomaterials are placed in bio-enviroments, various protein molecules will immediately accumulate on material surfaces forming a bioactive layer. Moreover, this protein layer plays an important role in determining the biocompatibility of materials. So this paper briefly reviews the protein adsorption on bioceramics surfaces, including the type of proteins absorbed, methods being used, factors effecting adsorption capacity and methods improving it, providing reference for the surface biological modification of bioactive ceramic materials.%近年来,生物陶瓷材料在替代因外伤或疾病而导致缺损的硬组织方面已获得广泛的应用,当材料被植入生物体内后,其表面立即会发生多种蛋白质分子的堆积,这一蛋白质层对于改变材料的表面性质起着重要的作用.因此,对生物材料表面蛋白吸附的考察已经成为评价材料生物相容性和生物活性的重要内容.本文就生物陶瓷表面蛋白吸附的主要种类、研究方法、影响因素及其改进研究等相关内容作一综述,以期为生物陶瓷表面生物学改性的研究提供基础理论参考.

  6. Protein Adsorption and Layer Formation at the Stainless Steel-Solution Interface Mediates Shear-Induced Particle Formation for an IgG1 Monoclonal Antibody.

    Science.gov (United States)

    Kalonia, Cavan K; Heinrich, Frank; Curtis, Joseph E; Raman, Sid; Miller, Maria A; Hudson, Steven D

    2018-03-05

    Passage of specific protein solutions through certain pumps, tubing, and/or filling nozzles can result in the production of unwanted subvisible protein particles (SVPs). In this work, surface-mediated SVP formation was investigated. Specifically, the effects of different solid interface materials, interfacial shear rates, and protein concentrations on SVP formation were measured for the National Institute of Standards and Technology monoclonal antibody (NISTmAb), a reference IgG1 monoclonal antibody (mAb). A stainless steel rotary piston pump was used to identify formulation and process parameters that affect aggregation, and a flow cell (alumina or stainless steel interface) was used to further investigate the effect of different interface materials and/or interfacial shear rates. SVP particles produced were monitored using flow microscopy or flow cytometry. Neutron reflectometry and a quartz crystal microbalance with dissipation monitoring were used to characterize adsorption and properties of NISTmAb at the stainless steel interface. Pump/shear cell experiments showed that the NISTmAb concentration and interface material had a significant effect on SVP formation, while the effects of interfacial shear rate and passage number were less important. At the higher NISTmAb concentrations, the adsorbed protein became structurally altered at the stainless steel interface. The primary adsorbed layer remained largely undisturbed during flow, suggesting that SVP formation at high NISTmAb concentration was caused by the disruption of patches and/or secondary interactions.

  7. Functionalization of alkyne-terminated thermally hydrocarbonized porous silicon nanoparticles with targeting peptides and antifouling polymers: effect on the human plasma protein adsorption.

    Science.gov (United States)

    Wang, Chang-Fang; Mäkilä, Ermei M; Bonduelle, Colin; Rytkönen, Jussi; Raula, Janne; Almeida, Sérgio; Närvänen, Ale; Salonen, Jarno J; Lecommandoux, Sebastien; Hirvonen, Jouni T; Santos, Hélder A

    2015-01-28

    Porous silicon (PSi) nanomaterials combine a high drug loading capacity and tunable surface chemistry with various surface modifications to meet the requirements for biomedical applications. In this work, alkyne-terminated thermally hydrocarbonized porous silicon (THCPSi) nanoparticles were fabricated and postmodified using five bioactive molecules (targeting peptides and antifouling polymers) via a single-step click chemistry to modulate the bioactivity of the THCPSi nanoparticles, such as enhancing the cellular uptake and reducing the plasma protein association. The size of the nanoparticles after modification was increased from 176 to 180-220 nm. Dextran 40 kDa modified THCPSi nanoparticles showed the highest stability in aqueous buffer. Both peptide- and polymer-functionalized THCPSi nanoparticles showed an extensive cellular uptake which was dependent on the functionalized moieties presented on the surface of the nanoparticles. The plasma protein adsorption study showed that the surface modification with different peptides or polymers induced different protein association profiles. Dextran 40 kDa functionalized THCPSi nanoparticles presented the least protein association. Overall, these results demonstrate that the "click" conjugation of the biomolecules onto the alkyne-terminated THCPSi nanoparticles is a versatile and simple approach to modulate the surface chemistry, which has high potential for biomedical applications.

  8. Protein kinase C prevents oligodendrocyte differentiation : Modulation of actin cytoskeleton and cognate polarized membrane traffic

    NARCIS (Netherlands)

    Baron, W; de Vries, EJ; de Vries, H; Hoekstra, D

    1999-01-01

    In a previous study, we showed that activation of protein kinase C (PKC) prevents oligodendrocyte differentiation at the pro-oligodendrocyte stage. The present study was undertaken to identify downstream targets of PKC action in oligodendrocyte progenitor cells. Activation of PKC induced the

  9. The role of tears in preventing protein deposition on contact lenses

    NARCIS (Netherlands)

    Boot, N.; Kok, J.; Kijlstra, A.

    1989-01-01

    Recently the presence of a coating inhibitory factor was described in human tears which can prevent the binding of proteins to a solid phase. In these earlier studies depositions of lactoferrin and IgG onto plastic was studied. In the study described here, peroxidase conjugated albumin was used as a

  10. Evaluation of the in vitro differential protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (NLCs) for potential targeting to the brain.

    Science.gov (United States)

    Kasongo, Kasongo Wa; Jansch, Mirko; Müller, Rainer H; Walker, Roderick B

    2011-09-01

    The preferential in vitro adsorption of apolipoprotein E (Apo E) onto the surface of colloidal drug carriers may be used as a strategy to evaluate the in vivo potential for such systems to transport drugs to the brain. The aim of this research was to investigate the in vitro protein adsorption patterns of didanosine-loaded nanostructured lipid carriers (DDI-NLCs), using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), in order to establish the potential for NLCs to deliver DDI to the brain. NLC formulations were manufactured using high-pressure homogenization using a lipid matrix consisting of a mixture of Precirol(®) ATO 5 and Transcutol(®) HP. The 2-D PAGE analysis revealed that NLCs in formulations stabilized using Solutol(®) HS 15 alone or with a ternary surfactant system consisting of Solutol(®) HS 15, Tween(®) 80, and Lutrol(®) F68, preferentially adsorbed proteins, such as Apo E. Particles stabilized with Tween(®) 80 and Lutrol(®) F68 did not adsorb Apo E in these studies, which could be related to the relatively large particle size and hence small surface area observed for these NLCs. These findings have revealed that DDI-loaded NLCs may have the potential to deliver DDI to the brain in vivo and, in addition, to Tween(®) 80, which has already been shown to have the ability to facilitate the targeting of colloidal drug delivery systems to the brain. Solutol(®) HS 15-stabilized nanoparticles may also achieve a similar purpose.

  11. Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.; Dohnalkova, Alice; Smit, John; Jiao, Yongqin

    2016-09-23

    ABSTRACT

    Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaFaand RsaFb, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrug efflux pumps. Here we provide evidence that, unlike TolC, RsaFaand RsaFbare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaFaand RsaFbare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaFaand RsaFbled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaFaand RsaFbled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaFaand RsaFbin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels in

  12. Adsorption of proteins at the solution/air interface influenced by added nonionic surfactants at very low concentrations for both components. 3. Dilational surface rheology.

    Science.gov (United States)

    Fainerman, V B; Aksenenko, E V; Lylyk, S V; Lotfi, M; Miller, R

    2015-03-05

    The influence of the addition of the nonionic surfactants C12DMPO, C14DMPO, C10OH, and C10EO5 at concentrations between 10(-5) and 10(-1) mmol/L to solutions of β-casein (BCS) and β-lactoglobulin (BLG) at a fixed concentration of 10(-5) mmol/L on the dilational surface rheology is studied. A maximum in the viscoelasticity modulus |E| occurs at very low surfactant concentrations (10(-4) to 10(-3) mmol/L) for mixtures of BCS with C12DMPO and C14DMPO and for mixtures of BLG with C10EO5, while for mixture of BCS with C10EO5 the value of |E| only slightly increased. The |E| values calculated with a recently developed model, which assumes changes in the interfacial molar area of the protein molecules due to the interaction with the surfactants, are in satisfactory agreement with experimental data. A linear dependence exists between the ratio of the maximum modulus for the mixture to the modulus of the single protein solution and the coefficient reflecting the influence of the surfactants on the adsorption activity of the protein.

  13. Conformational aspects of proteins at the air/water interface studied by infrared reflection-adsorption spectroscopy

    NARCIS (Netherlands)

    Martin, A.H.; Meinders, M.B.J.; Bos, M.A.; Cohen Stuart, M.A.; Vliet, van T.

    2003-01-01

    From absorption spectra obtained with infrared reflection-absorption spectroscopy (IRRAS), it is possible to obtain information on conformational changes at a secondary folding level of proteins adsorbed at the air/water interface. In addition, information on protein concentration at the interface

  14. Fibrinogen adsorption on blocked surface of albumin

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2011-01-01

    We have investigated the adsorption of albumin and fibrinogen onto PET (polyethylene terephthalate) and glass surfaces and how pre-adsorption of albumin onto these surfaces can affect the adsorption of later added fibrinogen. For materials and devices being exposed to blood, adsorption...... of fibrinogen is often a non-wanted event, since fibrinogen is part of the clotting cascade and unspecific adsorption of fibrinogen can have an influence on the activation of platelets. Albumin is often used as blocking agent for avoiding unspecific protein adsorption onto surfaces in devices designed to handle...... energies, the adsorption of both albumin and fibrinogen has been monitored simultaneously on the same sample. Information about topography and coverage of adsorbed protein layers has been obtained using AFM (Atomic Force Microscopy) analysis in liquid. Our studies show that albumin adsorbs in a multilayer...

  15. Depletion of cellular poly (A) binding protein prevents protein synthesis and leads to apoptosis in HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Thangima Zannat, Mst.; Bhattacharjee, Rumpa B. [Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G2W1 (Canada); Bag, Jnanankur, E-mail: jbag@uoguelph.ca [Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G2W1 (Canada)

    2011-05-13

    Highlights: {yields} Depletion of cellular PABP level arrests mRNA translation in HeLa cells. {yields} PABP knock down leads to apoptotic cell death. {yields} PABP depletion does not affect transcription. {yields} PABP depletion does not lead to nuclear accumulation of mRNA. -- Abstract: The cytoplasmic poly (A) binding protein (PABP) is important in mRNA translation and stability. In yeast, depletion of PABP leads to translation arrest. Similarly, the PABP gene in Drosophila is important for proper development. It is however uncertain, whether mammalian PABP is essential for mRNA translation. Here we showed the effect of PABP depletion on mRNA metabolism in HeLa cells by using a small interfering RNA. Our results suggest that depletion of PABP prevents protein synthesis and consequently leads to cell death through apoptosis. Interestingly, no detectable effect of PABP depletion on transcription, transport and stability of mRNA was observed.

  16. Depletion of cellular poly (A) binding protein prevents protein synthesis and leads to apoptosis in HeLa cells

    International Nuclear Information System (INIS)

    Thangima Zannat, Mst.; Bhattacharjee, Rumpa B.; Bag, Jnanankur

    2011-01-01

    Highlights: → Depletion of cellular PABP level arrests mRNA translation in HeLa cells. → PABP knock down leads to apoptotic cell death. → PABP depletion does not affect transcription. → PABP depletion does not lead to nuclear accumulation of mRNA. -- Abstract: The cytoplasmic poly (A) binding protein (PABP) is important in mRNA translation and stability. In yeast, depletion of PABP leads to translation arrest. Similarly, the PABP gene in Drosophila is important for proper development. It is however uncertain, whether mammalian PABP is essential for mRNA translation. Here we showed the effect of PABP depletion on mRNA metabolism in HeLa cells by using a small interfering RNA. Our results suggest that depletion of PABP prevents protein synthesis and consequently leads to cell death through apoptosis. Interestingly, no detectable effect of PABP depletion on transcription, transport and stability of mRNA was observed.

  17. Heme-binding plasma membrane proteins of K562 erythroleukemia cells: Adsorption to heme-microbeads, isolation with affinity chromatography

    International Nuclear Information System (INIS)

    Majuri, R.

    1989-01-01

    Heme-microbeads attached themselves to the surface of viable K562 cells in a manner inhibitable by free hemin, indicating heme-recptor interaction. The microbeads were at first evenly distributed, but after prolonged incubation at 37 deg. C they formed a cap on one pole of the cells indicating clustering of the membrane heme receptors. Membrane proteins were labeled by culturing the cells in the presence of 35 S-methionine and were then solubilized with Triton X-114. The hydrophobic proteins contained about 20% of the total bound label. The solubilized membrane proteins were subsequently adsorbed to a heme-Sepharose affinity gel. According to SDS-electrophorsis and subsequent autoradiography, the immobilized heme captures two proteins or a protein with two polypeptides of 20 000 and 32 000 daltons. The larger of these was only wekly labeled with 35 S. The same two bands were observed if the cell surface proteins were labeled with 125 I by the lactoperoxidase method and the subsequently solubilized membrane proteins were isolated with heme-Sepharose. (author)

  18. Adsorption of protein GlnB of Herbaspirillum seropedicae on Si(111) investigated by AFM and XPS.

    Science.gov (United States)

    Lubambo, A F; Benelli, E M; Klein, J; Schreiner, W; Camargo, P C

    2006-01-01

    The protein GlnB-Hs (GlnB of Herbaspirillum seropedicae) in diazotroph micro-organisms signalizes levels of nitrogen, carbon, and energy for a series of proteins involved in the regulation of expression and control of the activity of nitrogenase complex that converts atmospheric nitrogen in ammonia, resulting in biological nitrogen fixation. Its structure has already been determined by X-ray diffraction, revealing a trimer of (36 kDa) with lateral cavities having hydrophilic boundaries. The interactions of GlnB-Hs with the well-known Si(111) surface were investigated for different incubation times, protein concentrations in initial solution, deposition conditions, and substrate initial state. The protein solution was deposited on Si(111) and dried under controlled conditions. An atomic force microscope operating in dynamic mode shows images of circular, linear, and more complex donut-shaped protein arrangement, and also filament types of organization, which vary from a few nanometers to micrometers. Apparently, the filament formation was favored because of protein surface polarity when in contact with the silicon surface, following some specific orientation. The spin-coating technique was successfully used to obtain more uniform surface covering.

  19. Dependence on the mobile phase pH of the adsorption behavior of propranolol enantiomers on a cellulase protein used as the chiral selector

    Energy Technology Data Exchange (ETDEWEB)

    Fornstedt, T.; Goetmar, G.; Andersson, M.; Guiochon, G.

    1999-02-17

    The authors reported previously on the unusual thermodynamic characteristics of the enantioselective interactions between the enantiomers of the {beta}-blocker propranolol and the protein cellobiohydrolase I immobilized on silica. The adsorption of the more retained enantiomer, (S)-propranolol, is endothermic while that of the (R)-propranolol is exothermic. This causes a rapid increase of the selectivity factor with increasing temperature. In this work, the complex dependence of the selectivity factor on the pH of the solvent is studied. They determined the equilibrium isotherms of (R)- and (S)-propranolol in a wide concentration range (0.25 {micro}M to 1.1 mM) at six different mobile-phase pHs (4.7, 5.0, 5.2, 5.5, 5.7, and 6.0) and fitted the data obtained to the bi-Langmuir model. This gave the saturation capacity and the binding constant of the nonselective contribution for the two enantiomers. It also gave these parameters for the enantioselective contributions of each of them. The dependence of these parameters on the pH is discussed and interpreted in terms of the retention mechanism. Conclusions are in excellent agreement with recent, independent results on the structure of the protein obtained by X-ray crystallography.

  20. Calcium phosphate-gold nanoparticles nanocomposite for protein adsorption and mediator-free H{sub 2}O{sub 2} biosensor construction

    Energy Technology Data Exchange (ETDEWEB)

    Xu Qin [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Jiangsu Key Laboratory of Environmental Engineering and Monitoring, Yangzhou 225002 (China); Lu Guiju; Bian XiaoJun; Jin Gendi [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Wang Wei [School of Chemical and Biological Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Hu Xiaoya, E-mail: xyhu@yzu.edu.cn [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Jiangsu Key Laboratory of Environmental Engineering and Monitoring, Yangzhou 225002 (China); Wang Yang; Yang Zhanjun [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China)

    2012-04-01

    This work reports a new method for the preparation and application of a kind of biocompatible calcium phosphate-gold nanoparticles (Ca{sub 3}(PO{sub 4}){sub 2}-AuNPs) nanocomposite. UV-vis spectroscopy and transmittance electron microscopy (TEM) have been used to monitor the formation process of the nanocomposite and to examine the interaction between calcium phosphate and gold nanoparticles (AuNPs). The nanocomposite has multiple sites and improved conductivity which make it suitable for the binding of proteins to construct electrochemical sensors. Myoglobin (Mb) adsorbed on the nanocomposite retained its native structure which was proved by Fourier transform infrared spectroscopy (FTIR). Direct electron transfer between the adsorbed Mb and the electrode was observed. Further results demonstrated that the adsorbed Mb has good electrocatalytic activity towards the reduction of H{sub 2}O{sub 2} in the absence of any mediator. Highlights: Black-Right-Pointing-Pointer Using gelatin modified gold nanoparticles to prepare needle-like calcium phosphate. Black-Right-Pointing-Pointer Calcium phosphate provides multiple sites for protein adsorption. Black-Right-Pointing-Pointer Gold nanoparticles act as electron tunneling. Black-Right-Pointing-Pointer Myoglobin adsorbed on the material showed direct electrochemistry and good catalysis.

  1. Effect of surface microstructure and wettability on plasma protein adsorption to ZnO thin films prepared at different RF powers

    Energy Technology Data Exchange (ETDEWEB)

    Huang Zhanyun; Chen Min; Chen Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou 510275 (China); Pan Shirong, E-mail: stscdh@mail.sysu.edu.c [Artificial Heart Lab, the 1st Affiliate Hospital of Sun Yat-Sen University, Guangzhou 510080 (China)

    2010-10-01

    In this paper, the adsorption behavior of plasma proteins on the surface of ZnO thin films prepared by radio frequency (RF) sputtering under different sputtering powers was studied. The microstructures and surface properties of the ZnO thin films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible optical absorption spectroscopy and contact angle techniques. The results show that the ZnO thin films have better orientation of the (0 0 2) peak with increasing RF power, especially at around 160 W, and the optical band gap of the ZnO films varies from 3.2 to 3.4 eV. The contact angle test carried out by the sessile drop technique denoted a hydrophobic surface of the ZnO films, and the surface energy and adhesive work of the ZnO thin films decreased with increasing sputtering power. The amounts of human fibrinogen (HFG) and human serum albumin (HSA) adsorbing on the ZnO films and reference samples were determined by using enzyme-linked immunosorbent assay (ELISA). The results show that fewer plasma proteins and a smaller HFG/HSA ratio adsorb on the ZnO thin films' surface.

  2. Cell wall α-1,3-glucan prevents α-amylase adsorption onto fungal cell in submerged culture of Aspergillus oryzae.

    Science.gov (United States)

    Zhang, Silai; Sato, Hiroki; Ichinose, Sakurako; Tanaka, Mizuki; Miyazawa, Ken; Yoshimi, Akira; Abe, Keietsu; Shintani, Takahiro; Gomi, Katsuya

    2017-07-01

    We have previously reported that α-amylase (Taka-amylase A, TAA) activity disappears in the later stage of submerged Aspergillus oryzae culture as a result of TAA adsorption onto the cell wall. Chitin, one of the major components of the cell wall, was identified as a potential factor that facilitates TAA adsorption. However, TAA adsorption only occurred in the later stage of cultivation, although chitin was assumed to be sufficiently abundant in the cell wall regardless of the submerged culture period. This suggested the presence a factor that inhibits TAA adsorption to the cell wall in the early stage of cultivation. In the current study, we identified α-1,3-glucan as a potential inhibiting factor for TAA adsorption. We constructed single, double, and triple disruption mutants of three α-1,3-glucan synthase genes (agsA, agsB, and agsC) in A. oryzae. Growth characteristics and cell wall component analysis of these disruption strains showed that AgsB plays a major role in α-1,3-glucan synthesis. In the ΔagsB mutant, TAA was adsorbed onto the mycelium in all stages of cultivation (early and later), and the ΔagsB mutant cell walls had a significantly high capacity for TAA adsorption. Moreover, the α-1,3-glucan content of the cell wall prepared from the wild-type strain in the later stage of cultivation was markedly reduced compared with that in the early stage. These results suggest that α-1,3-glucan is a potential inhibiting factor for TAA adsorption onto the cell wall component, chitin, in the early stage of submerged culture in A. oryzae. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  3. The adsorption of α-amylase on barley proteins affects the in vitro digestion of starch in barley flour.

    Science.gov (United States)

    Yu, Wenwen; Zou, Wei; Dhital, Sushil; Wu, Peng; Gidley, Michael J; Fox, Glen P; Gilbert, Robert G

    2018-02-15

    The conversion of barley starch to sugars is a complex enzymic process. Most previous work concerned the biotechnical aspect of in situ barley enzymes. However, the interactions among the macromolecular substrates and their effects on enzymic catalysis has been little examined. Here, we explore the mechanisms whereby interactions of protein and starch in barley flour affect the kinetics of enzymatic hydrolysis of starch in an in vitro system, using digestion rate data and structural analysis by confocal microscopy. The degradation kinetics of both uncooked barley flour and of purified starches are found to be two-step sequential processes. Barley proteins, especially the water-soluble component, are found to retard the digestion of starch degraded by α-amylase: the enzyme binds with water-insoluble protein and with starch granules, leading to reduced starch hydrolysis. These findings are of potential industrial value in both the brewing and food industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Two familial ALS proteins function in prevention/repair of transcription-associated DNA damage.

    Science.gov (United States)

    Hill, Sarah J; Mordes, Daniel A; Cameron, Lisa A; Neuberg, Donna S; Landini, Serena; Eggan, Kevin; Livingston, David M

    2016-11-29

    Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron dysfunction disease that leads to paralysis and death. There is currently no established molecular pathogenesis pathway. Multiple proteins involved in RNA processing are linked to ALS, including FUS and TDP43, and we propose a disease mechanism in which loss of function of at least one of these proteins leads to an accumulation of transcription-associated DNA damage contributing to motor neuron cell death and progressive neurological symptoms. In support of this hypothesis, we find that FUS or TDP43 depletion leads to increased sensitivity to a transcription-arresting agent due to increased DNA damage. Thus, these proteins normally contribute to the prevention or repair of transcription-associated DNA damage. In addition, both FUS and TDP43 colocalize with active RNA polymerase II at sites of DNA damage along with the DNA damage repair protein, BRCA1, and FUS and TDP43 participate in the prevention or repair of R loop-associated DNA damage, a manifestation of aberrant transcription and/or RNA processing. Gaining a better understanding of the role(s) that FUS and TDP43 play in transcription-associated DNA damage could shed light on the mechanisms underlying ALS pathogenesis.

  5. Glial cell adhesion and protein adsorption on SAM coated semiconductor and glass surfaces of a microfluidic structure

    Science.gov (United States)

    Sasaki, Darryl Y.; Cox, Jimmy D.; Follstaedt, Susan C.; Curry, Mark S.; Skirboll, Steven K.; Gourley, Paul L.

    2001-05-01

    The development of microsystems that merge biological materials with microfabricated structures is highly dependent on the successful interfacial interactions between these innately incompatible materials. Surface passivation of semiconductor and glass surfaces with thin organic films can attenuate the adhesion of proteins and cells that lead to biofilm formation and biofouling of fluidic structures. We have examined the adhesion of glial cells and serum albumin proteins to microfabricated glass and semiconductor surfaces coated with self-assembled monolayers of octadecyltrimethoxysilane and N-(triethoxysilylpropyl)-O- polyethylene oxide urethane, to evaluate the biocompatibility and surface passivation those coatings provide.

  6. Small molecules targeting LapB protein prevent Listeria attachment to catfish muscle.

    Directory of Open Access Journals (Sweden)

    Ali Akgul

    Full Text Available Listeria monocytogenes is a Gram-positive foodborne pathogen and the causative agent of listeriosis. L. monocytogenes lapB gene encodes a cell wall surface anchor protein, and mutation of this gene causes Listeria attenuation in mice. In this work, the potential role of Listeria LapB protein in catfish fillet attachment was investigated. To achieve this, boron-based small molecules designed to interfere with the active site of the L. monocytogenes LapB protein were developed, and their ability to prevent L. monocytogenes attachment to fish fillet was tested. Results indicated that seven out of nine different small molecules were effective in reducing the Listeria attachment to catfish fillets. Of these, three small molecules (SM3, SM5, and SM7 were highly effective in blocking Listeria attachment to catfish fillets. This study suggests an alternative strategy for reduction of L. monocytogenes contamination in fresh and frozen fish products.

  7. The ribosome can prevent aggregation of partially folded protein intermediates: studies using the Escherichia coli ribosome.

    Directory of Open Access Journals (Sweden)

    Bani Kumar Pathak

    Full Text Available BACKGROUND: Molecular chaperones that support de novo folding of proteins under non stress condition are classified as chaperone 'foldases' that are distinct from chaperone' holdases' that provide high affinity binding platform for unfolded proteins and prevent their aggregation specifically under stress conditions. Ribosome, the cellular protein synthesis machine can act as a foldase chaperone that can bind unfolded proteins and release them in folding competent state. The peptidyl transferase center (PTC located in the domain V of the 23S rRNA of Escherichia coli ribosome (bDV RNA is the chaperoning center of the ribosome. It has been proposed that via specific interactions between the RNA and refolding proteins, the chaperone provides information for the correct folding of unfolded polypeptide chains. RESULTS: We demonstrate using Escherichia coli ribosome and variants of its domain V RNA that the ribosome can bind to partially folded intermediates of bovine carbonic anhydrase II (BCAII and lysozyme and suppress aggregation during their refolding. Using mutants of domain V RNA we demonstrate that the time for which the chaperone retains the bound protein is an important factor in determining its ability to suppress aggregation and/or support reactivation of protein. CONCLUSION: The ribosome can behave like a 'holdase' chaperone and has the ability to bind and hold back partially folded intermediate states of proteins from participating in the aggregation process. Since the ribosome is an essential organelle that is present in large numbers in all living cells, this ability of the ribosome provides an energetically inexpensive way to suppress cellular aggregation. Further, this ability of the ribosome might also be crucial in the context that the ribosome is one of the first chaperones to be encountered by a large nascent polypeptide chains that have a tendency to form partially folded intermediates immediately following their synthesis.

  8. Application of Minicircle Technology of Self-Reproducing Synthetic Protein Drugs in Preventing Skin Allograft Rejection.

    Science.gov (United States)

    Lim, Sun Woo; Kim, Young Kyun; Park, Narae; Jin, Long; Jin, Jian; Doh, Kyoung Chan; Ju, Ji Hyeon; Yang, Chul Woo

    2015-07-30

    Recently, it has been reported that minicircle vectors could allow the expression of transgenes using the protein synthesis system of the host. Here, we tested a novel strategy to permit the production of synthetic biologics using minicircle technology and evaluated their feasibility as a therapeutic tool in a skin allograft model. We engineered vectors to carry cassette sequences for tocilizumab [anti-soluble interleukin-6 receptor (sIL-6R) antibody] and/or etanercept [tumor necrosis factor receptor 2 (TNFR2)-Fc fusion protein], and then isolated minicircle vectors from the parent vectors. We verified the production of proteins from minicircles and their duration in HEK293T cells and mice. We also evaluated whether these proteins were expressed at levels sufficient to ameliorate skin allograft rejection in mice. Each minicircle transfected into cells was detectable for at least 30 days. In mice, the drugs were mainly expressed in the liver and were detectable for at least 10 days after a single injection. These drugs were also detected in the blood. Treatment of mice with minicircles prolonged skin allograft survival, which was accompanied by a reduction of the number of interferon-γ+ or interleukin-17+ lymphocytes and an induction of forkhead box P3 expression. These findings suggest that blocking of sIL-6R and/or TNF-α using minicircles encoding tocilizumab and/or etanercept was functionally active and relevant for preventing acute allograft rejection. Self-reproducing synthetic protein drugs produced using minicircle technology are potentially powerful tools for preventing acute rejection in transplantation.

  9. FTO genotype, dietary protein, and change in appetite: the Preventing Overweight Using Novel Dietary Strategies trial.

    Science.gov (United States)

    Huang, Tao; Qi, Qibin; Li, Yanping; Hu, Frank B; Bray, George A; Sacks, Frank M; Williamson, Donald A; Qi, Lu

    2014-05-01

    A common obesity-risk variant rs9939609 in the fat mass- and obesity-associated (FTO) gene was recently shown to affect appetite, and the gene is sensitive to the regulation of amino acids. We examined the interaction between FTO genotype and protein intake on the long-term changes in appetite in a randomized controlled trial. We genotyped FTO rs9939609 in 737 overweight adults in the 2-y Preventing Overweight Using Novel Dietary Strategies trial and assessed 4 appetite-related traits including cravings, fullness, hunger, and prospective consumption. We showed that dietary protein significantly modified genetic effects on changes in food cravings and appetite scores at 6 mo after adjustment for age, sex, ethnicity, baseline body mass index, weight change, and baseline value for respective outcomes (P-interaction = 0.027 and 0.048, respectively). The A allele was associated with a greater decrease in food cravings and appetite scores in participants with high-protein-diet intake (P = 0.027 and 0.047, respectively) but not in subjects in the low-protein-diet group (P = 0.384 and 0.078, respectively). The weight regain from 6 to 24 mo attenuated gene-protein interactions. Protein intakes did not modify FTO genotype effects on other appetite measures. Our data suggest that individuals with the FTO rs9939609 A allele might obtain more benefits in a reduction of food cravings and appetite by choosing a hypocaloric and higher-protein weight-loss diet. This trial was registered at clinicaltrials.gov as NCT00072995.

  10. Protein adsorption/desorption and antibody binding stoichiometry on silicon interferometric biosensors examined with TOF-SIMS

    KAUST Repository

    Gajos, Katarzyna

    2018-03-05

    Time-of-flight secondary ion mass spectrometry has been employed to examine, with biomolecular discrimination, sensing arm areas (20 μm x 600 μm) of integrated onto silicon chips Mach-Zehnder interferometers aiming to optimize their biofunctionalization with regard to indirect immunochemical (competitive) detection of ochratoxin A. Sensing areas are examined after: modification with (3-aminopropyl)triethoxysilane, spotting of OTA-ovalbumin conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin, reaction with OTA-specific mouse monoclonal antibody followed by goat anti-mouse IgG secondary antibody. Component mass loadings of all proteins involved in immunodetection are determined from TOF-SIMS micro-analysis combined with ellipsometry of planar surfaces. These data show that partial desorption of surface-bound probe and blocking protein takes place upon primary immunoreaction to a degree that depends on probe concentration in spotting solution. Taking into account this desorption, apparent binding stoichiometry of both antibodies in immune complexes formed onto chip surface is determined more accurately than the respective evaluation based on real-time sensor response. In addition, mass loadings for probe and secondary antibody is observed to saturate for optimum probe concentrations. Also, principal component analysis of TOF-SIMS data could resolve both immunoreactions and biofunctionalization and discriminate surfaces prepared with optimum probe concentrations from those prepared using suboptimum ones.

  11. Protein adsorption/desorption and antibody binding stoichiometry on silicon interferometric biosensors examined with TOF-SIMS

    KAUST Repository

    Gajos, Katarzyna; Budkowski, Andrzej; Petrou, Panagiota; Pagkali, Varvara; Awsiuk, Kamil; Rysz, Jakub; Bernasik, Andrzej; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

    2018-01-01

    Time-of-flight secondary ion mass spectrometry has been employed to examine, with biomolecular discrimination, sensing arm areas (20 μm x 600 μm) of integrated onto silicon chips Mach-Zehnder interferometers aiming to optimize their biofunctionalization with regard to indirect immunochemical (competitive) detection of ochratoxin A. Sensing areas are examined after: modification with (3-aminopropyl)triethoxysilane, spotting of OTA-ovalbumin conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin, reaction with OTA-specific mouse monoclonal antibody followed by goat anti-mouse IgG secondary antibody. Component mass loadings of all proteins involved in immunodetection are determined from TOF-SIMS micro-analysis combined with ellipsometry of planar surfaces. These data show that partial desorption of surface-bound probe and blocking protein takes place upon primary immunoreaction to a degree that depends on probe concentration in spotting solution. Taking into account this desorption, apparent binding stoichiometry of both antibodies in immune complexes formed onto chip surface is determined more accurately than the respective evaluation based on real-time sensor response. In addition, mass loadings for probe and secondary antibody is observed to saturate for optimum probe concentrations. Also, principal component analysis of TOF-SIMS data could resolve both immunoreactions and biofunctionalization and discriminate surfaces prepared with optimum probe concentrations from those prepared using suboptimum ones.

  12. Protein adsorption/desorption and antibody binding stoichiometry on silicon interferometric biosensors examined with TOF-SIMS

    Science.gov (United States)

    Gajos, Katarzyna; Budkowski, Andrzej; Petrou, Panagiota; Pagkali, Varvara; Awsiuk, Kamil; Rysz, Jakub; Bernasik, Andrzej; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

    2018-06-01

    Time-of-flight secondary ion mass spectrometry has been employed to examine, with biomolecular discrimination, sensing arm areas (20 μm × 600 μm) of integrated onto silicon chips Mach-Zehnder interferometers aiming to optimize their biofunctionalization with regard to indirect immunochemical (competitive) detection of ochratoxin A. Sensing areas are examined after: modification with (3-aminopropyl)triethoxysilane, spotting of OTA-ovalbumin conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin, reaction with OTA-specific mouse monoclonal antibody followed by goat anti-mouse IgG secondary antibody. Component mass loadings of all proteins involved in immunodetection are determined from TOF-SIMS micro-analysis combined with ellipsometry of planar surfaces. These data show that partial desorption of surface-bound probe and blocking protein takes place upon primary immunoreaction to a degree that depends on probe concentration in spotting solution. Taking into account this desorption, apparent binding stoichiometry of both antibodies in immune complexes formed onto chip surface is determined more accurately than the respective evaluation based on real-time sensor response. In addition, mass loadings for probe and secondary antibody is observed to saturate for optimum probe concentrations. Also, principal component analysis of TOF-SIMS data could resolve both immunoreactions and biofunctionalization and discriminate surfaces prepared with optimum probe concentrations from those prepared using suboptimum ones.

  13. Interactions of PLGA nanoparticles with blood components: protein adsorption, coagulation, activation of the complement system and hemolysis studies.

    Science.gov (United States)

    Fornaguera, Cristina; Calderó, Gabriela; Mitjans, Montserrat; Vinardell, Maria Pilar; Solans, Conxita; Vauthier, Christine

    2015-04-14

    The intravenous administration of poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been widely reported as a promising alternative for delivery of drugs to specific cells. However, studies on their interaction with diverse blood components using different techniques are still lacking. Therefore, in the present work, the interaction of PLGA nanoparticles with blood components was described using different complementary techniques. The influence of different encapsulated compounds/functionalizing agents on these interactions was also reported. It is worth noting that all these techniques can be simply performed, without the need for highly sophisticated apparatus or skills. Moreover, their transference to industries and application of quality control could be easily performed. Serum albumin was adsorbed onto all types of tested nanoparticles. The saturation concentration was dependent on the nanoparticle size. In contrast, fibrinogen aggregation was dependent on nanoparticle surface charge. The complement activation was also influenced by the nanoparticle functionalization; the presence of a functionalizing agent increased complement activation, while the addition of an encapsulated compound only caused a slight increase. None of the nanoparticles influenced the coagulation cascade at low concentrations. However, at high concentrations, cationized nanoparticles did activate the coagulation cascade. Interactions of nanoparticles with erythrocytes did not reveal any hemolysis. Interactions of PLGA nanoparticles with blood proteins depended both on the nanoparticle properties and the protein studied. Independent of their loading/surface functionalization, PLGA nanoparticles did not influence the coagulation cascade and did not induce hemolysis of erythrocytes; they could be defined as safe concerning induction of embolization and cell lysis.

  14. Systemic Immunization with Papillomavirus L1 Protein Completely Prevents the Development of Viral Mucosal Papillomas

    Science.gov (United States)

    Suzich, Joann A.; Ghim, Shin-Je; Palmer-Hill, Frances J.; White, Wendy I.; Tamura, James K.; Bell, Judith A.; Newsome, Joseph A.; Bennett Jenson, A.; Schlegel, Richard

    1995-12-01

    Infection of mucosal epithelium by papillomaviruses is responsible for the induction of genital and oral warts and plays a critical role in the development of human cervical and oropharyngeal cancer. We have employed a canine model to develop a systemic vaccine that completely protects against experimentally induced oral mucosal papillomas. The major capsid protein, L1, of canine oral papillomavirus (COPV) was expressed in Sf9 insect cells in native conformation. L1 protein, which self-assembled into virus-like particles, was purified on CsCl gradients and injected intradermally into the foot pad of beagles. Vaccinated animals developed circulating antibodies against COPV and became completely resistant to experimental challenge with COPV. Successful immunization was strictly dependent upon native L1 protein conformation and L1 type. Partial protection was achieved with as little as 0.125 ng of L1 protein, and adjuvants appeared useful for prolonging the host immune response. Serum immunoglobulins passively transferred from COPV L1-immunized beagles to naive beagles conferred protection from experimental infection with COPV. Our results indicate the feasibility of developing a human vaccine to prevent mucosal papillomas, which can progress to malignancy.

  15. Identification of potential cell wall component that allows Taka-amylase A adsorption in submerged cultures of Aspergillus oryzae.

    Science.gov (United States)

    Sato, Hiroki; Toyoshima, Yoshiyuki; Shintani, Takahiro; Gomi, Katsuya

    2011-12-01

    We observed that α-amylase (Taka-amylase A; TAA) activity in the culture broth disappeared in the later stage of submerged cultivation of Aspergillus oryzae. This disappearance was caused by adsorption of TAA onto the cell wall of A. oryzae and not due to protein degradation by extracellular proteolytic enzymes. To determine the cell wall component(s) that allows TAA adsorption efficiently, the cell wall was fractionated by stepwise alkali treatment and enzymatic digestion. Consequently, alkali-insoluble cell wall fractions exhibited high levels of TAA adsorption. In addition, this adsorption capacity was significantly enhanced by treatment of the alkali-insoluble fraction with β-glucanase, which resulted in the concomitant increase in the amount of chitin in the resulting fraction. In contrast, the adsorption capacity was diminished by treating the cell wall fraction with chitinase. These results suggest that the major component that allows TAA adsorption is chitin. However, both the mycelium and the cell wall demonstrated the inability to allow TAA adsorption in the early stage of cultivation, despite chitin content in the cell wall being identical in both early and late stages of cultivation. These results suggest the existence of unidentified factor(s) that could prevent the adsorption of TAA onto the cell wall. Such factor(s) is most likely removed or diminished from the cell wall following longer cultivation periods.

  16. Engineering a Biocompatible Scaffold with Either Micrometre or Nanometre Scale Surface Topography for Promoting Protein Adsorption and Cellular Response

    Directory of Open Access Journals (Sweden)

    Xuan Le

    2013-01-01

    Full Text Available Surface topographical features on biomaterials, both at the submicrometre and nanometre scales, are known to influence the physicochemical interactions between biological processes involving proteins and cells. The nanometre-structured surface features tend to resemble the extracellular matrix, the natural environment in which cells live, communicate, and work together. It is believed that by engineering a well-defined nanometre scale surface topography, it should be possible to induce appropriate surface signals that can be used to manipulate cell function in a similar manner to the extracellular matrix. Therefore, there is a need to investigate, understand, and ultimately have the ability to produce tailor-made nanometre scale surface topographies with suitable surface chemistry to promote favourable biological interactions similar to those of the extracellular matrix. Recent advances in nanoscience and nanotechnology have produced many new nanomaterials and numerous manufacturing techniques that have the potential to significantly improve several fields such as biological sensing, cell culture technology, surgical implants, and medical devices. For these fields to progress, there is a definite need to develop a detailed understanding of the interaction between biological systems and fabricated surface structures at both the micrometre and nanometre scales.

  17. Endoplasmic reticulum proteins SDF2 and SDF2L1 act as components of the BiP chaperone cycle to prevent protein aggregation.

    Science.gov (United States)

    Fujimori, Tsutomu; Suno, Ryoji; Iemura, Shun-Ichiro; Natsume, Tohru; Wada, Ikuo; Hosokawa, Nobuko

    2017-08-01

    The folding of newly synthesized proteins in the endoplasmic reticulum (ER) is assisted by ER-resident chaperone proteins. BiP (immunoglobulin heavy-chain-binding protein), a member of the HSP70 family, plays a central role in protein quality control. The chaperone function of BiP is regulated by its intrinsic ATPase activity, which is stimulated by ER-resident proteins of the HSP40/DnaJ family, including ERdj3. Here, we report that two closely related proteins, SDF2 and SDF2L1, regulate the BiP chaperone cycle. Both are ER-resident, but SDF2 is constitutively expressed, whereas SDF2L1 expression is induced by ER stress. Both luminal proteins formed a stable complex with ERdj3 and potently inhibited the aggregation of different types of misfolded ER cargo. These proteins associated with non-native proteins, thus promoting the BiP-substrate interaction cycle. A dominant-negative ERdj3 mutant that inhibits the interaction between ERdj3 and BiP prevented the dissociation of misfolded cargo from the ERdj3-SDF2L1 complex. Our findings indicate that SDF2 and SDF2L1 associate with ERdj3 and act as components in the BiP chaperone cycle to prevent the aggregation of misfolded proteins, partly explaining the broad folding capabilities of the ER under various physiological conditions. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  18. Preventive effect of fermented Maillard reaction products from milk proteins in cardiovascular health.

    Science.gov (United States)

    Oh, N S; Kwon, H S; Lee, H A; Joung, J Y; Lee, J Y; Lee, K B; Shin, Y K; Baick, S C; Park, M R; Kim, Y; Lee, K W; Kim, S H

    2014-01-01

    The aim of this study was to determine the dual effect of Maillard reaction and fermentation on the preventive cardiovascular effects of milk proteins. Maillard reaction products (MRP) were prepared from the reaction between milk proteins, such as whey protein concentrates (WPC) and sodium caseinate (SC), and lactose. The hydrolysates of MRP were obtained from fermentation by lactic acid bacteria (LAB; i.e., Lactobacillus gasseri H10, L. gasseri H11, Lactobacillus fermentum H4, and L. fermentum H9, where human-isolated strains were designated H1 to H15), which had excellent proteolytic and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities (>20%). The antioxidant activity of MRP was greater than that of intact proteins in assays of the reaction with 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and trivalent ferric ions; moreover, the effect of MRP was synergistically improved by fermentation. The Maillard reaction dramatically increased the level of antithrombotic activity and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) inhibitory effect of milk proteins, but did not change the level of activity for micellar cholesterol solubility. Furthermore, specific biological properties were enhanced by fermentation. Lactobacillus gasseri H11 demonstrated the greatest activity for thrombin and HMGR inhibition in Maillard-reacted WPC, by 42 and 33%, respectively, whereas hydrolysates of Maillard-reacted SC fermented by L. fermentum H9 demonstrated the highest reduction rate for micellar cholesterol solubility, at 52%. In addition, the small compounds that were likely released by fermentation of MRP were identified by size-exclusion chromatography. Therefore, MRP and hydrolysates of fermented MRP could be used to reduce cardiovascular risks. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. Hydrolyzed whey protein prevents the development of food allergy to β-lactoglobulin in sensitized mice.

    Science.gov (United States)

    Gomes-Santos, Ana Cristina; Fonseca, Roberta Cristelli; Lemos, Luisa; Reis, Daniela Silva; Moreira, Thaís Garcias; Souza, Adna Luciana; Silva, Mauro Ramalho; Silvestre, Marialice Pinto Coelho; Cara, Denise Carmona; Faria, Ana Maria Caetano

    2015-01-01

    Food allergy is an adverse immune response to dietary proteins. Hydrolysates are frequently used for children with milk allergy. However, hydrolysates effects afterwards are poorly studied. The aim of this study was to investigate the immunological consequences of hydrolyzed whey protein in allergic mice. For that, we developed a novel model of food allergy in BALB/c mice sensitized with alum-adsorbed β-lactoglobulin. These mice were orally challenged with either whey protein or whey hydrolysate. Whey-challenged mice had elevated levels of specific IgE and lost weight. They also presented gut inflammation, enhanced levels of SIgA and IL-5 as well as decreased production of IL-4 and IL-10 in the intestinal mucosa. Conversely, mice challenged with hydrolyzate maintained normal levels of IgE, IL-4 and IL-5 and showed no sign of gut inflammation probably due to increased IL-12 production in the gut. Thus, consumption of hydrolysate prevented the development of clinical signs of food allergy in mice. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Dendrobium chrysotoxum Lindl. Alleviates Diabetic Retinopathy by Preventing Retinal Inflammation and Tight Junction Protein Decrease

    Science.gov (United States)

    Yu, Zengyang; Gong, Chenyuan; Lu, Bin; Yang, Li; Sheng, Yuchen; Ji, Lili; Wang, Zhengtao

    2015-01-01

    Diabetic retinopathy (DR) is a serious complication of diabetes mellitus. This study aimed to observe the alleviation of the ethanol extract of Dendrobium chrysotoxum Lindl. (DC), a traditional Chinese herbal medicine, on DR and its engaged mechanism. After DC (30 or 300 mg/kg) was orally administrated, the breakdown of blood retinal barrier (BRB) in streptozotocin- (STZ-) induced diabetic rats was attenuated by DC. Decreased retinal mRNA expression of tight junction proteins (including occludin and claudin-1) in diabetic rats was also reversed by DC. Western blot analysis and retinal immunofluorescence staining results further confirmed that DC reversed the decreased expression of occludin and claudin-1 proteins in diabetic rats. DC reduced the increased retinal mRNA expressions of intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNFα), interleukin- (IL-) 6, and IL-1β in diabetic rats. In addition, DC alleviated the increased 1 and phosphorylated p65, IκB, and IκB kinase (IKK) in diabetic rats. DC also reduced the increased serum levels of TNFα, interferon-γ (IFN-γ), IL-6, IL-1β, IL-8, IL-12, IL-2, IL-3, and IL-10 in diabetic rats. Therefore, DC can alleviate DR by inhibiting retinal inflammation and preventing the decrease of tight junction proteins, such as occludin and claudin-1. PMID:25685822

  1. Fibrinogen adsorption on blocked surface of albumin.

    Science.gov (United States)

    Holmberg, Maria; Hou, Xiaolin

    2011-05-01

    We have investigated the adsorption of albumin and fibrinogen onto PET (polyethylene terephthalate) and glass surfaces and how pre-adsorption of albumin onto these surfaces can affect the adsorption of later added fibrinogen. For materials and devices being exposed to blood, adsorption of fibrinogen is often a non-wanted event, since fibrinogen is part of the clotting cascade and unspecific adsorption of fibrinogen can have an influence on the activation of platelets. Albumin is often used as blocking agent for avoiding unspecific protein adsorption onto surfaces in devices designed to handle biological samples, including protein solutions. It is based on the assumption that proteins adsorbs as a monolayer on surfaces and that proteins do not adsorb on top of each other. By labelling albumin and fibrinogen with two different radioactive iodine isotopes that emit gamma radiation with different energies, the adsorption of both albumin and fibrinogen has been monitored simultaneously on the same sample. Information about topography and coverage of adsorbed protein layers has been obtained using AFM (Atomic Force Microscopy) analysis in liquid. Our studies show that albumin adsorbs in a multilayer fashion on PET and that fibrinogen adsorbs on top of albumin when albumin is pre-adsorbed on the surfaces. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. ADSORPTION AND RELEASING PROPERTIES OF BEAD CELLULOSE

    Institute of Scientific and Technical Information of China (English)

    A. Morales; E. Bordallo; V. Leon; J. Rieumont

    2004-01-01

    The adsorption of some dyes on samples of bead cellulose obtained in the Unit of Research-Production "Cuba 9"was studied. Methylene blue, alizarin red and congo red fitted the adsorption isotherm of Langmuir. Adsorption kinetics at pH = 6 was linear with the square root of time indicating the diffusion is the controlling step. At pH = 12 a non-Fickian trend was observed and adsorption was higher for the first two dyes. Experiments carried out to release the methylene blue occluded in the cellulose beads gave a kinetic behavior of zero order. The study of cytochrome C adsorption was included to test a proteinic material. Crosslinking of bead cellulose was performed with epichlorohydrin decreasing its adsorption capacity in acidic or alkaline solution.

  3. Immunoglobulin adsorption on modified surfaces

    NARCIS (Netherlands)

    Bremer, M.G.E.G.

    2001-01-01

    Preservation of biological functioning of proteins during immobilisation is of special interest in various biomedical and biotechnical applications. In industry physical adsorption of immunoglobulins (IgGs) onto solid surfaces is still the predominant immobilisation procedure because it is

  4. Quantitative determination of BAF312, a S1P-R modulator, in human urine by LC-MS/MS: prevention and recovery of lost analyte due to container surface adsorption.

    Science.gov (United States)

    Li, Wenkui; Luo, Suyi; Smith, Harold T; Tse, Francis L S

    2010-02-15

    Analyte loss due to non-specific binding, especially container surface adsorption, is not uncommon in the quantitative analysis of urine samples. In developing a sensitive LC-MS/MS method for the determination of a drug candidate, BAF312, in human urine, a simple procedure was outlined for identification, confirmation and prevention of analyte non-specific binding to a container surface and to recover the 'non-specific loss' of an analyte, if no transfer has occurred to the original urine samples. Non-specific binding or container surface adsorption can be quickly identified by using freshly spiked urine calibration standards and pre-pooled QC samples during a LC-MS/MS feasibility run. The resulting low recovery of an analyte in urine samples can be prevented through the use of additives, such as the non-ionic surfactant Tween-80, CHAPS and others, to the container prior to urine sample collection. If the urine samples have not been transferred from the bulk container, the 'non-specific binding' of an analyte to the container surface can be reversed by the addition of a specified amount of CHAPS, Tween-80 or bovine serum albumin, followed by appropriate mixing. Among the above agents, Tween-80 is the most cost-effective. beta-cyclodextrin may be suitable in stabilizing the analyte of interest in urine via pre-treating the matrix with the agent. However, post-addition of beta-cyclodextrin to untreated urine samples does not recover the 'lost' analyte due to non-specific binding or container surface adsorption. In the case of BAF312, a dynamic range of 0.0200-20.0 ng/ml in human urine was validated with an overall accuracy and precision for QC sample results ranging from -3.2 to 5.1% (bias) and 3.9 to 10.2% (CV), respectively. Pre- and post-addition of 0.5% (v/v) Tween-80 to the container provided excellent overall analyte recovery and minimal MS signal suppression when a liquid-liquid extraction in combination with an isocratic LC separation was employed. The

  5. Zinc in the prevention of Fe2initiated lipid and protein oxidation

    Directory of Open Access Journals (Sweden)

    M. PAOLA ZAGO

    2000-01-01

    Full Text Available In the present study we characterized the capacity of zinc to protect lipids and proteins from Fe2+-initiated oxidative damage. The effects of zinc on lipid oxidation were investigated in liposomes composed of brain phosphatidylcholine (PC and phosphatidylserine (PS at a molar relationship of 60:40 (PC:PS, 60:40. Lipid oxidation was evaluated as the oxidation of cis-parinaric acid or as the formation of 2-thiobarbituric acid-reactive substances (TBARS. Zinc protected liposomes from Fe2+ (2.5-50 muM-supported lipid oxidation. However, zinc (50 muM did not prevent the oxidative inactivation of glutamine synthelase and glucose 6-phosphate dehydrogenase when rat brain superntants were oxidized in the presence of 5 muM Fe2+ and 0.5 mM H2O2 .We also studied the interactions of zinc with epicatechin in the prevention of liid oxidation in liposomes. The simulaneous addition of 0.5 muM epicatechin (EC and 50 muM zinc or EC separately. Zinc (50 muM also protecte liposomes from the stimulatory effect of aluminum on Fe2+-initiated lipid oxidation. Zinc could play an important role as an antioxidant in biological systems, replacing iron and other metals with pro-oxidant activity from binding sites and interacting with other components of the oxidant defense system.

  6. Prevention

    DEFF Research Database (Denmark)

    Halken, S; Høst, A

    2001-01-01

    , breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation...... populations. These theories remain to be documented in proper, controlled and prospective studies. Breastfeeding and the late introduction of solid foods (>4 months) is associated with a reduced risk of food allergy, atopic dermatitis, and recurrent wheezing and asthma in early childhood. In all infants....... Preventive dietary restrictions after the age of 4-6 months are not scientifically documented....

  7. Small heat shock protein αA-crystallin prevents photoreceptor degeneration in experimental autoimmune uveitis.

    Directory of Open Access Journals (Sweden)

    Narsing A Rao

    Full Text Available The small heat shock protein, αA-crystallin null (αA-/- mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU. In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB, a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA-/- and wild type mice with EAU as donors and Rag2-/- as the recipient mice, which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ, both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses.

  8. Small heat shock protein αA-crystallin prevents photoreceptor degeneration in experimental autoimmune uveitis.

    Science.gov (United States)

    Rao, Narsing A; Saraswathy, Sindhu; Pararajasegaram, Geeta; Bhat, Suraj P

    2012-01-01

    The small heat shock protein, αA-crystallin null (αA-/-) mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU). In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB), a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA-/- and wild type mice with EAU as donors and Rag2-/- as the recipient mice), which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ), both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses.

  9. Preventive Effects of Chitosan Coacervate Whey Protein on Body Composition and Immunometabolic Aspect in Obese Mice

    Directory of Open Access Journals (Sweden)

    Gabriel Inácio de Morais Honorato de Souza

    2014-01-01

    Full Text Available Functional foods containing bioactive compounds of whey may play an important role in prevention and treatment of obesity. The aim of this study was to investigate the prospects of the biotechnological process of coacervation of whey proteins (CWP in chitosan and test its antiobesogenic potential. Methods. CWP (100 mg·kg·day was administered in mice with diet-induced obesity for 8 weeks. The animals were divided into four groups: control normocaloric diet gavage with water (C or coacervate (C-CWP, and high fat diet gavage with water (HF or coacervate (HF-CWP. Results. HF-CWP reduced weight gain and serum lipid fractions and displayed reduced adiposity and insulin. Adiponectin was significantly higher in HF-CWP group when compared to the HF. The level of LPS in HF-W group was significantly higher when compared to HF-CWP. The IL-10 showed an inverse correlation between the levels of insulin and glucose in the mesenteric adipose tissue in the HF-CWP group. CWP promoted an increase in both phosphorylation AMPK and the amount of ATGL in the mesenteric adipose tissue in HF-CWP group. Conclusion. CWP was able to modulate effects, possibly due to its high biological value of proteins. We observed a protective effect against obesity and improved the inflammatory milieu of white adipose tissue.

  10. The Ixodes scapularis Salivary Protein, Salp15, Prevents the Association of HIV-1 gp120 and CD4

    OpenAIRE

    Juncadella, Ignacio J.; Garg, Renu; Bates, Tonya C.; Olivera, Elias R.; Anguita, Juan

    2007-01-01

    Ixodes scapularis salivary protein, Salp15, inhibits CD4+ T cell activation by binding to the most-extracellular domains of the CD4 molecule, potentially overlapping with the gp120-binding region. We now show that Salp15 inhibits the interaction of gp120 and CD4. Furthermore, Salp15 prevents syncytia formation between HL2/3 (a stable HeLa cell line expressing the envelope protein) and CD4-expressing cells. Salp15 prevented gp120-CD4 interaction at least partially through its direct interactio...

  11. Evaluation of the potassium adsorption capacity of a potassium adsorption filter during rapid blood transfusion.

    Science.gov (United States)

    Matsuura, H; Akatsuka, Y; Muramatsu, C; Isogai, S; Sugiura, Y; Arakawa, S; Murayama, M; Kurahashi, M; Takasuga, H; Oshige, T; Yuba, T; Mizuta, S; Emi, N

    2015-05-01

    The concentration of extracellular potassium in red blood cell concentrates (RCCs) increases during storage, leading to risk of hyperkalemia. A potassium adsorption filter (PAF) can eliminate the potassium at normal blood transfusion. This study aimed to investigate the potassium adsorption capacity of a PAF during rapid blood transfusion. We tested several different potassium concentrations under a rapid transfusion condition using a pressure bag. The adsorption rates of the 70-mEq/l model were 76·8%. The PAF showed good potassium adsorption capacity, suggesting that this filter may provide a convenient method to prevent hyperkalemia during rapid blood transfusion. © 2015 International Society of Blood Transfusion.

  12. Chemical modification of protein A chromatography ligands with polyethylene glycol. I: Effects on IgG adsorption equilibrium, kinetics, and transport.

    Science.gov (United States)

    Weinberg, Justin; Zhang, Shaojie; Crews, Gillian; Carta, Giorgio; Przybycien, Todd

    2018-04-20

    Chemical modification of Protein A (ProA) chromatography ligands with polyethylene glycol (PEGylation) has been proposed as a strategy to increase the process selectivity and resin robustness by providing the ligand with a steric repulsion barrier against non-specific binding. This article comprises a comprehensive study of IgG adsorption and transport in Repligen CaptivA PriMAB resin with PEGylated ProA ligands that are modified using 5.2 and 21.5 kDa PEG chains. We studied the impact of the molecular weight of the PEG as well as the extent of PEGylation for the 5.2 kDa PEG modification. In all cases, PEGylation of ProA ligands decreases the resin average pore size, particle porosity, and static binding capacity for IgG proportional to the volume of conjugated PEG in the resin. Resin batch uptake experiments conducted in bulk via a stirred-tank system and with individual resin particles under confocal laser scanning microscopy suggests that PEGylation introduces heterogeneity into IgG binding kinetics: a fraction of the IgG binding sites are transformed from typical fast association kinetic behavior to slow kinetic behavior. pH gradient elution experiments of an IgG molecule on the modified resins show an increase in IgG elution pH for all modified resins, implying a decrease in IgG-ProA binding affinity on modification. Despite losses in static binding capacity for all resins with PEGylated ligands, the loss of dynamic binding capacity at 10% breakthrough (DBC 10% ) ranged more broadly from almost 0-47% depending on the PEG molecular weight and the extent of PEGylation. Minimal losses in DBC 10% were observed with a low extent of PEGylation with a smaller molecular weight PEG, while higher losses were observed at higher extents of PEGylation and with higher molecular weight PEG due to decreased static binding capacity and increased mass transfer resistance. This work provides insight into the practical implications for resin performance if PEGylation is

  13. The Accelerated Late Adsorption of Pulmonary Surfactant

    Science.gov (United States)

    2011-01-01

    Adsorption of pulmonary surfactant to an air−water interface lowers surface tension (γ) at rates that initially decrease progressively, but which then accelerate close to the equilibrium γ. The studies here tested a series of hypotheses concerning mechanisms that might cause the late accelerated drop in γ. Experiments used captive bubbles and a Wilhelmy plate to measure γ during adsorption of vesicles containing constituents from extracted calf surfactant. The faster fall in γ reflects faster adsorption rather than any feature of the equation of state that relates γ to surface concentration (Γ). Adsorption accelerates when γ reaches a critical value rather than after an interval required to reach that γ. The hydrophobic surfactant proteins (SPs) represent key constituents, both for reaching the γ at which the acceleration occurs and for producing the acceleration itself. The γ at which rates of adsorption increase, however, is unaffected by the Γ of protein in the films. In the absence of the proteins, a phosphatidylethanolamine, which, like the SPs, induces fusion of the vesicles with the interfacial film, also causes adsorption to accelerate. Our results suggest that the late acceleration is characteristic of adsorption by fusion of vesicles with the nascent film, which proceeds more favorably when the Γ of the lipids exceeds a critical value. PMID:21417351

  14. Catalase activity prevents exercise-induced up-regulation of vasoprotective proteins in venous tissue.

    Science.gov (United States)

    Dao, Vu Thao-Vi; Floeren, Melanie; Kumpf, Stephanie; Both, Charlotte; Peter, Bärbel; Balz, Vera; Suvorava, Tatsiana; Kojda, Georg

    2011-11-01

    Physical activity induces favourable changes of arterial gene expression and protein activity, although little is known about its effect in venous tissue. Although our understanding of the initiating molecular signals is still incomplete, increased expression of endothelial nitric oxide synthase (eNOS) is considered a key event. This study sought to investigate the effects of two different training protocols on the expression of eNOS and extracellular superoxide dismutase (ecSOD) in venous and lung tissue and to evaluate the underlying molecular mechanisms. C57Bl/6 mice underwent voluntary exercise or forced physical activity. Changes of vascular mRNA and protein levels and activity of eNOS, ecSOD and catalase were determined in aorta, heart, lung and vena cava. Both training protocols similarly increased relative heart weight and resulted in up-regulation of aortic and myocardial eNOS. In striking contrast, eNOS expression in vena cava and lung remained unchanged. Likewise, exercise up-regulated ecSOD in the aorta and in left ventricular tissue but remained unchanged in lung tissue. Catalase expression in lung tissue and vena cava of exercised mice exceeded that in aorta by 6.9- and 10-fold, respectively, suggesting a lack of stimulatory effects of hydrogen peroxide. In accordance, treatment of mice with the catalase inhibitor aminotriazole for 6 weeks resulted in significant up-regulation of eNOS and ecSOD in vena cava. These data suggest that physiological venous catalase activity prevents exercise-induced up-regulation of eNOS and ecSOD. Furthermore, therapeutic inhibition of vascular catalase might improve pulmonary rehabilitation. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

  15. Reduction of protein adsorption to a solid surface by a coating composed of polymeric micelles with a glass-like core

    NARCIS (Netherlands)

    Hofs, P.S.; Brzozowska, A.M.; Keizer, de A.; Norde, W.; Cohen Stuart, M.A.

    2008-01-01

    Adsorption studies by optical reflectometry show that complex coacervate core micelles (C3Ms) composed of poly([4-(2-amino-ethylthio)-butylene] hydrochloride)49-block-poly(ethylene oxide)212 and poly([4-(2-carboxy-ethylthio)-butylene] sodium salt)47-block-poly(ethylene oxide)212 adsorb in equal

  16. Reduction of protein adsorption to a solid surface by a coating composed of polymeric micelles with a glass-like core

    NARCIS (Netherlands)

    Hofs, B.; Brzozowska, A.; de Keizer, A.; Norde, W.; Stuart, Martien A. Cohen

    2008-01-01

    Adsorption studies by optical reflectometry show that complex coacervate core micelles (C3Ms) composed of poly([4-(2-amino-ethylthio)-butylene]hydrochloride)(49)-block-poly(ethylene oxide)(212) and poly([4-(2carboxy-ethylthio)-butylene] sodium salt)(47)-block-poly(ethylene oxide)(212) adsorb in

  17. The Cellular Prion Protein Prevents Copper-Induced Inhibition of P2X4 Receptors

    Directory of Open Access Journals (Sweden)

    Ramón A. Lorca

    2011-01-01

    Full Text Available Although the physiological function of the cellular prion protein (PrPC remains unknown, several evidences support the notion of its role in copper homeostasis. PrPC binds Cu2+ through a domain composed by four to five repeats of eight amino acids. Previously, we have shown that the perfusion of this domain prevents and reverses the inhibition by Cu2+ of the adenosine triphosphate (ATP-evoked currents in the P2X4 receptor subtype, highlighting a modulatory role for PrPC in synaptic transmission through regulation of Cu2+ levels. Here, we study the effect of full-length PrPC in Cu2+ inhibition of P2X4 receptor when both are coexpressed. PrPC expression does not significantly change the ATP concentration-response curve in oocytes expressing P2X4 receptors. However, the presence of PrPC reduces the inhibition by Cu2+ of the ATP-elicited currents in these oocytes, confirming our previous observations with the Cu2+ binding domain. Thus, our observations suggest a role for PrPC in modulating synaptic activity through binding of extracellular Cu2+.

  18. Global epidemiology of serogroup B meningococcal disease and opportunities for prevention with novel recombinant protein vaccines.

    Science.gov (United States)

    Villena, Rodolfo; Safadi, Marco Aurelio P; Valenzuela, María Teresa; Torres, Juan P; Finn, Adam; O'Ryan, Miguel

    2018-04-18

    Meningococcal disease (MD) is a major cause of meningitis and sepsis worldwide, with a high case fatality rate and frequent sequelae. Neisseria meningitidis serogroups A, B, C, W, X and Y are responsible for most of these life-threatening infections, and its unpredictable epidemiology can cause outbreaks in communities, with significant health, social and economic impact. Currently, serogroup B is the main cause of MD in Europe and North America and one of the most prevalent serogroups in Latin America. Mass vaccination strategies using polysaccharide vaccines have been deployed since the 1970s and the use of conjugate vaccines has controlled endemic and epidemic disease caused by serogroups A, C, W and Y and more recently serogroup B using geographically-specific outer membrane vesicle based vaccines. Two novel protein-based vaccines are a significant addition to our armamentarium against N. meningitidis as they provide broad coverage against highly diverse strains in serogroup B and other groups. Early safety, effectiveness and impact data of these vaccines are encouraging. These novel serogroup B vaccines should be actively considered for individuals at increased risk of disease and to control serogroup B outbreaks occurring in institutions or specific regions, as they are likely to save lives and prevent severe sequelae. Incorporation into national programs will require thorough country-specific analysis.

  19. Beyond the role of dietary protein and amino acids in the prevention of diet-induced obesity.

    Science.gov (United States)

    Petzke, Klaus J; Freudenberg, Anne; Klaus, Susanne

    2014-01-20

    High-protein diets have been shown to prevent the development of diet-induced obesity and can improve associated metabolic disorders in mice. Dietary leucine supplementation can partially mimic this effect. However, the molecular mechanisms triggering these preventive effects remain to be satisfactorily explained. Here we review studies showing a connection between high protein or total amino nitrogen intake and obligatory water intake. High amino nitrogen intake may possibly lower lipid storage, and prevent insulin resistance. Suggestions are made for further systematical studies to explore the relationship between water consumption, satiety, and energy expenditure. Moreover, these examinations should better distinguish between leucine-specific and unspecific effects. Research in this field can provide important information to justify dietary recommendations and strategies in promoting long-term weight loss and may help to reduce health problems associated with the comorbidities of obesity.

  20. Severe Hemolysis in a Patient With Erythrocytosis During Coupled Plasma Filtration Adsorption Therapy Was Prevented by Changing From Membrane-Based Technique to a Centrifuge-Based One.

    Science.gov (United States)

    Fan, Rong; Wu, Buyun; Kong, Ling; Gong, Dehua

    2016-01-01

    Coupled plasma filtration adsorption (CPFA) usually adopts membrane to separate plasma from blood. Here, we reported a case with erythrocytosis experienced severe hemolysis and membrane rupture during CPFA, which was avoided by changing from membrane-based technique to a centrifuge-based one. A 66-year-old man was to receive CPFA for severe hyperbilirubinemia (total bilirubin 922 μmol/L, direct bilirubin 638 μmol/L) caused by obstruction of biliary tract. He had erythrocytosis (hemoglobin 230 g/L, hematocrit 0.634) for years because of untreated tetralogy of Fallot. Severe hemolysis and membrane rupture occurred immediately after blood entering into the plasma separator even at a low flow rate (50 mL/min) and persisted after changing a new separator. Finally, centrifugal plasma separation technique was used for CPFA in this patient, and no hemolysis occurred. After 3 sessions of CPFA, total bilirubin level decreased to 199 μmol/L with an average decline by 35% per session. Thereafter, the patient received endoscopic biliary stent implantation, and total bilirubin level returned to nearly normal. Therefore, centrifugal-based plasma separation can also be used in CPFA and may be superior to a membrane-based one in patients with hyperviscosity.

  1. mTORC1 Coordinates Protein Synthesis and Immunoproteasome Formation via PRAS40 to Prevent Accumulation of Protein Stress.

    Science.gov (United States)

    Yun, Young Sung; Kim, Kwan Hyun; Tschida, Barbara; Sachs, Zohar; Noble-Orcutt, Klara E; Moriarity, Branden S; Ai, Teng; Ding, Rui; Williams, Jessica; Chen, Liqiang; Largaespada, David; Kim, Do-Hyung

    2016-02-18

    Reduction of translational fidelity often occurs in cells with high rates of protein synthesis, generating defective ribosomal products. If not removed, such aberrant proteins can be a major source of cellular stress causing human diseases. Here, we demonstrate that mTORC1 promotes the formation of immunoproteasomes for efficient turnover of defective proteins and cell survival. mTORC1 sequesters precursors of immunoproteasome β subunits via PRAS40. When activated, mTORC1 phosphorylates PRAS40 to enhance protein synthesis and simultaneously to facilitate the assembly of the β subunits for forming immunoproteasomes. Consequently, the PRAS40 phosphorylations play crucial roles in clearing aberrant proteins that accumulate due to mTORC1 activation. Mutations of RAS, PTEN, and TSC1, which cause mTORC1 hyperactivation, enhance immunoproteasome formation in cells and tissues. Those mutations increase cellular dependence on immunoproteasomes for stress response and survival. These results define a mechanism by which mTORC1 couples elevated protein synthesis with immunoproteasome biogenesis to protect cells against protein stress. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Rosuvastatin, inflammation, C-reactive protein, JUPITER, and primary prevention of cardiovascular disease--a perspective.

    Science.gov (United States)

    Kones, Richard

    2010-12-09

    The major public health concern worldwide is coronary heart disease, with dyslipidemia as a major risk factor. Statin drugs are recommended by several guidelines for both primary and secondary prevention. Rosuvastatin has been widely accepted because of its efficacy, potency, and superior safety profile. Inflammation is involved in all phases of atherosclerosis, with the process beginning in early youth and advancing relentlessly for decades throughout life. C-reactive protein (CRP) is a well-studied, nonspecific marker of inflammation which may reflect general health risk. Considerable evidence suggests CRP is an independent predictor of future cardiovascular events, but direct involvement in atherosclerosis remains controversial. Rosuvastatin is a synthetic, hydrophilic statin with unique stereochemistry. A large proportion of patients achieve evidence-based lipid targets while using the drug, and it slows progression and induces regression of atherosclerotic coronary lesions. Rosuvastatin lowers CRP levels significantly. The Justification for Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial was designed after the observation that when both low density lipoprotein and CRP were reduced, patients fared better than when only LDL was lowered. Advocates and critics alike acknowledge that the benefits of rosuvastatin in JUPITER were real. After a review, the US Food and Drug Administration extended the indications for rosuvastatin to include asymptomatic JUPITER-eligible individuals with one additional risk factor. The American Heart Association and Centers of Disease Control and Prevention had previously recognized the use of CRP in persons with "intermediate risk" as defined by global risk scores. The Canadian Cardiovascular Society guidelines went further and recommended use of statins in persons with low LDL and high CRP levels at intermediate risk. The JUPITER study focused attention on ostensibly healthy individuals with

  3. Association of protein intake with the change of lean mass among elderly women: The Osteoporosis Risk Factor and Prevention - Fracture Prevention Study (OSTPRE-FPS).

    Science.gov (United States)

    Isanejad, Masoud; Mursu, Jaakko; Sirola, Joonas; Kröger, Heikki; Rikkonen, Toni; Tuppurainen, Marjo; Erkkilä, Arja T

    2015-01-01

    Low protein intake can lead to declined lean mass (LM) in elderly. We examined the associations of total protein (TP), animal protein (AP) and plant protein (PP) intakes with LM. The association of TP intake with LM change was further evaluated according to weight change status. This cross-sectional and prospective cohort study included 554 women aged 68 (sd 1·9) years from the Osteoporosis Risk Factor and Prevention - Fracture Prevention Study (OSTPRE-FPS). The intervention group (n 270) received daily cholecalciferol (800 IU; 20 μg) and Ca (1000 mg) for 3 years while the control group received neither supplementation nor placebo (n 282). Participants filled out a questionnaire on lifestyle factors and a 3-d food record in 2002 and underwent dual-energy X-ray absorptiometry for body composition measurements at baseline and 3 years. Multiple linear regressions evaluated the association between protein intake and LM, adjusting for relevant covariates. At the baseline TP and AP intakes were positively associated with LM and trunk LM, TP was associated also with appendicular LM (aLM). Follow-up results showed that in the total population and the intervention group, higher TP and AP were associated with increased LM and aLM (P ≤ 0·050). No such associations were observed in the control group. PP intake was also associated with aLM change in the total population. Overall, the associations were independent of fat mass. Further, among weight maintainers, TP intake was positively associated with LM, aLM and trunk LM changes (P ≤ 0·020). In conclusion, dietary TP, especially AP, intake may be a modifiable risk factor for sarcopenia by preserving LM in the elderly.

  4. Studies to Prevent Degradation of Recombinant Fc-Fusion Protein Expressed in Mammalian Cell Line and Protein Characterization

    Directory of Open Access Journals (Sweden)

    Sanjukta Chakrabarti

    2016-06-01

    Full Text Available Clipping of recombinant proteins is a major issue in animal cell cultures. A recombinant Fc-fusion protein, VEGFR1(D1–D3-Fc expressed in CHOK1SV GS-KO cells was observed to be undergoing clippings in lab scale cultures. Partial cleaving of expressed protein initiated early on in cell culture and was observed to increase over time in culture and also on storage. In this study, a few parameters were explored in a bid to inhibit clipping in the fusion protein The effects of culture temperature, duration of culture, the addition of an anti-clumping agent, ferric citrate and use of protease inhibitor cocktail on inhibition of proteolysis of the Fc fusion were studied. Lowering of culture temperature from 37 to 30 °C alone appears to be the best solution for reducing protein degradation from the quality, cost and regulatory points of view. The obtained Fc protein was characterized and found to be in its stable folded state, exhibiting a high affinity for its ligand and also biological and functional activities.

  5. Adsorption of proteins at the solution/air interface influenced by added nonionic surfactants at very low concentrations for both components. 2. Effect of different surfactants and theoretical model.

    Science.gov (United States)

    Fainerman, V B; Lotfi, M; Javadi, A; Aksenenko, E V; Tarasevich, Yu I; Bastani, D; Miller, R

    2014-11-04

    The influence of the addition of the nonionic surfactants dodecyl dimethyl phosphine oxide (C12DMPO), tetradecyl dimethyl phosphine oxide (C14DMPO), decyl alcohol (C10OH), and C10EO5 at concentrations between 10(-5) and 10(-1) mmol/L to solutions of β-casein (BCS) and β-lactoglobulin (BLG) at a fixed concentration of 10(-5) mmol/L on the surface tension is studied. It is shown that a significant decrease of the water/air surface tension occurs for all the surfactants studied at very low concentrations (10(-5)-10(-3) mmol/L). All measurements were performed with the buoyant bubble profile method. The dynamics of the surface tension was simulated using the Fick and Ward-Tordai equations. The calculation results agree well with the experimental data, indicating that the equilibration times in the system studied do not exceed 30 000 s, while the time required to attain the equilibrium on a plane surface is by one order of magnitude higher. To achieve agreement between theory and experiment for the mixtures, a supposition was made about the influence of the concentration of nonionic surfactant on the adsorption activity of the protein. The adsorption isotherm equation of the protein was modified accordingly, and this corrected model agrees well with all experimental data.

  6. Matrix metalloproteinase-20 mediates dental enamel biomineralization by preventing protein occlusion inside apatite crystals.

    Science.gov (United States)

    Prajapati, Saumya; Tao, Jinhui; Ruan, Qichao; De Yoreo, James J; Moradian-Oldak, Janet

    2016-01-01

    Reconstruction of enamel-like materials is a central topic of research in dentistry and material sciences. The importance of precise proteolytic mechanisms in amelogenesis to form a hard tissue with more than 95% mineral content has already been reported. A mutation in the Matrix Metalloproteinase-20 (MMP-20) gene results in hypomineralized enamel that is thin, disorganized and breaks from the underlying dentin. We hypothesized that the absence of MMP-20 during amelogenesis results in the occlusion of amelogenin in the enamel hydroxyapatite crystals. We used spectroscopy and electron microscopy techniques to qualitatively and quantitatively analyze occluded proteins within the isolated enamel crystals from MMP-20 null and Wild type (WT) mice. Our results showed that the isolated enamel crystals of MMP-20 null mice had more organic macromolecules occluded inside them than enamel crystals from the WT. The crystal lattice arrangements of MMP-20 null enamel crystals analyzed by High Resolution Transmission Electron Microscopy (HRTEM) were found to be significantly different from those of the WT. Raman studies indicated that the crystallinity of the MMP-20 null enamel crystals was lower than that of the WT. In conclusion, we present a novel functional mechanism of MMP-20, specifically prevention of unwanted organic material entrapped in the forming enamel crystals, which occurs as the result of precise amelogenin cleavage. MMP-20 action guides the growth morphology of the forming hydroxyapatite crystals and enhances their crystallinity. Elucidating such molecular mechanisms can be applied in the design of novel biomaterials for future clinical applications in dental restoration or repair. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Lipid, lipoproteins, C-reactive protein, and hemostatic factors at baseline in the diabetes prevention program.

    Science.gov (United States)

    2005-10-01

    Individuals with impaired glucose tolerance (IGT) appear to be at increased risk for cardiovascular disease (CVD) due at least in part to an increased prevalence of risk factors. We evaluated lipid, lipoprotein, C-reactive protein (CRP), fibrinogen, and tissue plasminogen activator (tPA) levels at study entry in the largest multiethnic cohort of participants with IGT described, namely in the Diabetes Prevention Program (DPP). Measurements were performed at the baseline visit of 3,819 randomized participants of the DPP. Among 3,622 participants who were not taking lipid-lowering medicines, cardiovascular risk factors were analyzed in relation to demographic, anthropometric, and metabolic measures. Major determinants of risk factors were assessed in multivariate analysis. Over 40% of participants had elevated triglyceride, LDL cholesterol, and CRP levels and reduced HDL cholesterol levels. Men had higher triglyceride and tPA and lower HDL cholesterol concentrations and smaller LDL particle size than women, whereas women had higher CRP and fibrinogen levels. African Americans had less dyslipidemia but higher fibrinogen levels, and Asian Americans had lower CRP and fibrinogen levels than Caucasians and Hispanics. The surrogate measure of insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]) had the strongest association with HDL cholesterol, triglyceride, and tPA levels and LDL particle size. BMI had the greatest influence on CRP and fibrinogen levels. Using median splits of indexes of insulin resistance and insulin secretion (insulin-to-glucose ratio), participants with greater insulin resistance had a more adverse CVD risk-factor profile, whereas insulin secretion had little influence on risk factors. The pattern of CVD risk factors in participants with IGT in the DPP exhibits substantial heterogeneity and is significantly influenced by race, sex, and age, as well as by obesity, glucose, and insulin measures. The degree of insulin

  8. Hydroxyapatite hierarchically nanostructured porous hollow microspheres: rapid, sustainable microwave-hydrothermal synthesis by using creatine phosphate as an organic phosphorus source and application in drug delivery and protein adsorption.

    Science.gov (United States)

    Qi, Chao; Zhu, Ying-Jie; Lu, Bing-Qiang; Zhao, Xin-Yu; Zhao, Jing; Chen, Feng; Wu, Jin

    2013-04-22

    Hierarchically nanostructured porous hollow microspheres of hydroxyapatite (HAP) are a promising biomaterial, owing to their excellent biocompatibility and porous hollow structure. Traditionally, synthetic hydroxyapatite is prepared by using an inorganic phosphorus source. Herein, we report a new strategy for the rapid, sustainable synthesis of HAP hierarchically nanostructured porous hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through a microwave-assisted hydrothermal method. The as-obtained products are characterized by powder X-ray diffraction (XRD), Fourier-transform IR (FTIR) spectroscopy, SEM, TEM, Brunauer-Emmett-Teller (BET) nitrogen sorptometry, dynamic light scattering (DLS), and thermogravimetric analysis (TGA). SEM and TEM micrographs show that HAP hierarchically nanostructured porous hollow microspheres consist of HAP nanosheets or nanorods as the building blocks and DLS measurements show that the diameters of HAP hollow microspheres are within the range 0.8-1.5 μm. The specific surface area and average pore size of the HAP porous hollow microspheres are 87.3 m(2) g(-1) and 20.6 nm, respectively. The important role of creatine phosphate disodium salt and the influence of the experimental conditions on the products were systematically investigated. This method is facile, rapid, surfactant-free and environmentally friendly. The as-prepared HAP porous hollow microspheres show a relatively high drug-loading capacity and protein-adsorption ability, as well as sustained drug and protein release, by using ibuprofen as a model drug and hemoglobin (Hb) as a model protein, respectively. These experiments indicate that the as-prepared HAP porous hollow microspheres are promising for applications in biomedical fields, such as drug delivery and protein adsorption. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Targeting activator protein 1 signaling pathway by bioactive natural agents: Possible therapeutic strategy for cancer prevention and intervention.

    Science.gov (United States)

    Tewari, Devesh; Nabavi, Seyed Fazel; Nabavi, Seyed Mohammad; Sureda, Antoni; Farooqi, Ammad Ahmad; Atanasov, Atanas G; Vacca, Rosa Anna; Sethi, Gautam; Bishayee, Anupam

    2018-02-01

    Activator protein 1 (AP-1) is a key transcription factor in the control of several cellular processes responsible for cell survival proliferation and differentiation. Dysfunctional AP-1 expression and activity are involved in several severe diseases, especially inflammatory disorders and cancer. Therefore, targeting AP-1 has recently emerged as an attractive therapeutic strategy for cancer prevention and therapy. This review summarizes our current understanding of AP-1 biology and function as well as explores and discusses several natural bioactive compounds modulating AP-1-associated signaling pathways for cancer prevention and intervention. Current limitations, challenges, and future directions of research are also critically discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein

    NARCIS (Netherlands)

    Ridker, Paul M.; Danielson, Eleanor; Fonseca, Francisco A. H.; Genest, Jacques; Gotto, Antonio M.; Kastelein, John J. P.; Koenig, Wolfgang; Libby, Peter; Lorenzatti, Alberto J.; Macfadyen, Jean G.; Nordestgaard, Børge G.; Shepherd, James; Willerson, James T.; Glynn, Robert J.; Ridker, P. M.; Fonseca, F. A. H.; Genest, J.; Gotto, A. M.; Koenig, W.; Libby, P.; Lorenzatti, A. J.; Nordestgaard, B. G.; Shepherd, J.; Willerson, J. T.; Danielson, E.; Glynn, R. J.; MacFadyen, J. G.; Mora, S.; Collins, R.; Bailey, K.; Gersh, B.; Lamas, G.; Smith, S.; Vaughan, D.; Mahaffey, K.; Brown, P.; Montgomery, D.; Wilson, M.; Wood, F.; Altamirano, J.; Boskis, P.; Colombo, H.; Cuneo, C.; Diaz, M.; Esper, R.; Trip, M.; Hoekstra, J.; Koch, S.; Lucas, M.; van de Beek, M.

    2008-01-01

    BACKGROUND: Increased levels of the inflammatory biomarker high-sensitivity C-reactive protein predict cardiovascular events. Since statins lower levels of high-sensitivity C-reactive protein as well as cholesterol, we hypothesized that people with elevated high-sensitivity C-reactive protein levels

  11. LSD1 demethylase and the methyl-binding protein PHF20L1 prevent SET7 methyltransferase-dependent proteolysis of the stem-cell protein SOX2.

    Science.gov (United States)

    Zhang, Chunxiao; Hoang, Nam; Leng, Feng; Saxena, Lovely; Lee, Logan; Alejo, Salvador; Qi, Dandan; Khal, Anthony; Sun, Hong; Lu, Fei; Zhang, Hui

    2018-03-09

    The pluripotency-controlling stem-cell protein SRY-box 2 (SOX2) plays a pivotal role in maintaining the self-renewal and pluripotency of embryonic stem cells and also of teratocarcinoma or embryonic carcinoma cells. SOX2 is monomethylated at lysine 119 (Lys-119) in mouse embryonic stem cells by the SET7 methyltransferase, and this methylation triggers ubiquitin-dependent SOX2 proteolysis. However, the molecular regulators and mechanisms controlling SET7-induced SOX2 proteolysis are unknown. Here, we report that in human ovarian teratocarcinoma PA-1 cells, methylation-dependent SOX2 proteolysis is dynamically regulated by the LSD1 lysine demethylase and a methyl-binding protein, PHD finger protein 20-like 1 (PHF20L1). We found that LSD1 not only removes the methyl group from monomethylated Lys-117 (equivalent to Lys-119 in mouse SOX2), but it also demethylates monomethylated Lys-42 in SOX2, a reaction that SET7 also regulated and that also triggered SOX2 proteolysis. Our studies further revealed that PHF20L1 binds both monomethylated Lys-42 and Lys-117 in SOX2 and thereby prevents SOX2 proteolysis. Down-regulation of either LSD1 or PHF20L1 promoted SOX2 proteolysis, which was prevented by SET7 inactivation in both PA-1 and mouse embryonic stem cells. Our studies also disclosed that LSD1 and PHF20L1 normally regulate the growth of pluripotent mouse embryonic stem cells and PA-1 cells by preventing methylation-dependent SOX2 proteolysis. In conclusion, our findings reveal an important mechanism by which the stability of the pluripotency-controlling stem-cell protein SOX2 is dynamically regulated by the activities of SET7, LSD1, and PHF20L1 in pluripotent stem cells. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Characterizing and modeling protein-surface interactions in lab-on-chip devices

    Science.gov (United States)

    Katira, Parag

    Protein adsorption on surfaces determines the response of other biological species present in the surrounding solution. This phenomenon plays a major role in the design of biomedical and biotechnological devices. While specific protein adsorption is essential for device function, non-specific protein adsorption leads to the loss of device function. For example, non-specific protein adsorption on bioimplants triggers foreign body response, in biosensors it leads to reduced signal to noise ratios, and in hybrid bionanodevices it results in the loss of confinement and directionality of molecular shuttles. Novel surface coatings are being developed to reduce or completely prevent the non-specific adsorption of proteins to surfaces. A novel quantification technique for extremely low protein coverage on surfaces has been developed. This technique utilizes measurement of the landing rate of microtubule filaments on kinesin proteins adsorbed on a surface to determine the kinesin density. Ultra-low limits of detection, dynamic range, ease of detection and availability of a ready-made kinesin-microtubule kit makes this technique highly suitable for detecting protein adsorption below the detection limits of standard techniques. Secondly, a random sequential adsorption model is presented for protein adsorption to PEO-coated surfaces. The derived analytical expressions accurately predict the observed experimental results from various research groups, suggesting that PEO chains act as almost perfect steric barriers to protein adsorption. These expressions can be used to predict the performance of a variety of systems towards resisting protein adsorption and can help in the design of better non-fouling surface coatings. Finally, in biosensing systems, target analytes are captured and concentrated on specifically adsorbed proteins for detection. Non-specific adsorption of proteins results in the loss of signal, and an increase in the background. The use of nanoscale transducers as

  13. Proteins in Soy Might Have a Higher Role in Cancer Prevention than Previously Expected: Soybean Protein Fractions Are More Effective MMP-9 Inhibitors Than Non-Protein Fractions, Even in Cooked Seeds

    Directory of Open Access Journals (Sweden)

    Ana Lima

    2017-02-01

    Full Text Available The search for anticancer MMP-9 inhibitors (MMPIs in food products has become a major goal for research. MMPIs in soy have been related only to saponins and isoflavones, but recently, low specific protein fractions in soybeans were shown to reduce MMP-9 activity as well. The present work aimed at comparing the MMPI potential of protein fractions (P and non-protein fractions (NP isolated from soybean seeds, before and after soaking and cooking, mimicking dietary exposures. Reverse and substrate zymography, as well as a fluoregenic DQ gelatin assay were used to evaluate MMP-9 activities. Colon cancer cell migration and proliferation was also tested in HT29 cells. Regarding MMP-9 inhibition, proteins in soy presented IC50 values 100 times lower than non-protein extracts, and remained active after cooking, suggesting that proteins may be more effective MMP-9 inhibitors than non-protein compounds. Using the determined IC50 concentrations, NP fractions were able to induce higher inhibitions of HT29 cell migration and proliferation, but not through MMP-9 inhibition, whilst protein fractions were shown to specifically inhibit MMP-9 activity. Overall, our results show that protein fractions in soybeans might have a higher role in soy-related cancer prevention as MMPIs than previously expected. Being nontoxic and active at lower concentrations, the discovery of these heat-resistant specific MMPI proteins in soy can be of significant importance for cancer preventive diets, particularly considering the increasing use of soy proteins in food products and the controversy around isoflavones amongst consumers.

  14. Activated protein C and its potential applications in prevention of islet β-cell damage and diabetes.

    Science.gov (United States)

    Xue, Meilang; Jackson, Christopher J

    2014-01-01

    Activated protein C (APC) is derived from its precursor, protein C (PC). Originally thought to be synthesized exclusively by the liver, recent reports have shown that PC is also produced by many other cells including pancreatic islet β cells. APC functions as a physiological anticoagulant with anti-inflammatory, anti-apoptotic, and barrier-stabilizing properties. APC exerts its protective effects via an intriguing mechanism requiring combinations of endothelial PC receptor, protease-activated receptors, epidermal growth factor receptor, Tie2 or CD11b, depending on cell types. Diabetes is a chronic condition resulted from the body's inability to produce and/or properly use insulin. The prevalence of diabetes has risen dramatically and has become one of the major causes of premature mortality and morbidity worldwide. Diabetes prevention is an ideal approach to reduce this burden. Type 1 and type 2 diabetes are the major forms of diabetes mellitus, and both are characterized by an autoimmune response, intraislet inflammation, β-cell apoptosis, and progressive β-cell loss. Protecting β-cell from damage is critical in both prevention and treatment of diabetes. Recent in vitro and animal studies show that APC's strong anti-inflammatory and anti-apoptotic properties are beneficial in preventing β-cell destruction and diabetes in the NOD mouse model of type 1 diabetes. Future preventive and therapeutic uses of APC in diabetes look very promising. © 2014 Elsevier Inc. All rights reserved.

  15. Binding to the minor groove of the double-strand, tau protein prevents DNA from damage by peroxidation.

    Science.gov (United States)

    Wei, Yan; Qu, Mei-Hua; Wang, Xing-Sheng; Chen, Lan; Wang, Dong-Liang; Liu, Ying; Hua, Qian; He, Rong-Qiao

    2008-07-02

    Tau, an important microtubule associated protein, has been found to bind to DNA, and to be localized in the nuclei of both neurons and some non-neuronal cells. Here, using electrophoretic mobility shifting assay (EMSA) in the presence of DNA with different chain-lengths, we observed that tau protein favored binding to a 13 bp or a longer polynucleotide. The results from atomic force microscopy also showed that tau protein preferred a 13 bp polynucleotide to a 12 bp or shorter polynucleotide. In a competitive assay, a minor groove binder distamycin A was able to replace the bound tau from the DNA double helix, indicating that tau protein binds to the minor groove. Tau protein was able to protect the double-strand from digestion in the presence of DNase I that was bound to the minor groove. On the other hand, a major groove binder methyl green as a negative competitor exhibited little effect on the retardation of tau-DNA complex in EMSA. This further indicates the DNA minor groove as the binding site for tau protein. EMSA with truncated tau proteins showed that both the proline-rich domain (PRD) and the microtubule-binding domain (MTBD) contributed to the interaction with DNA; that is to say, both PRD and MTBD bound to the minor groove of DNA and bent the double-strand, as observed by electron microscopy. To investigate whether tau protein is able to prevent DNA from the impairment by hydroxyl free radical, the chemiluminescence emitted by the phen-Cu/H(2)O(2)/ascorbate was measured. The emission intensity of the luminescence was markedly decreased when tau protein was present, suggesting a significant protection of DNA from the damage in the presence of hydroxyl free radical.

  16. Analysis of Casein Biopolymers Adsorption to Lignocellulosic Biomass as a Potential Cellulase Stabilizer

    Science.gov (United States)

    Eckard, Anahita Dehkhoda; Muthukumarappan, Kasiviswanathan; Gibbons, William

    2012-01-01

    Although lignocellulosic materials have a good potential to substitute current feedstocks used for ethanol production, conversion of these materials to fermentable sugars is still not economical through enzymatic hydrolysis. High cost of cellulase has prompted research to explore techniques that can prevent from enzyme deactivation. Colloidal proteins of casein can form monolayers on hydrophobic surfaces that alleviate the de-activation of protein of interest. Scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), capillary electrophoresis (CE), and Kjeldahl and BSA protein assays were used to investigate the unknown mechanism of action of induced cellulase activity during hydrolysis of casein-treated biomass. Adsorption of casein to biomass was observed with all of the analytical techniques used and varied depending on the pretreatment techniques of biomass. FT-IR analysis of amides I and II suggested that the substructure of protein from casein or skim milk were deformed at the time of contact with biomass. With no additive, the majority of one of the cellulase mono-component, 97.1 ± 1.1, was adsorbed to CS within 24 h, this adsorption was irreversible and increased by 2% after 72 h. However, biomass treatment with skim-milk and casein reduced the adsorption to 32.9% ± 6.0 and 82.8% ± 6.0, respectively. PMID:23118515

  17. Analysis of casein biopolymers adsorption to lignocellulosic biomass as a potential cellulase stabilizer.

    Science.gov (United States)

    Eckard, Anahita Dehkhoda; Muthukumarappan, Kasiviswanathan; Gibbons, William

    2012-01-01

    Although lignocellulosic materials have a good potential to substitute current feedstocks used for ethanol production, conversion of these materials to fermentable sugars is still not economical through enzymatic hydrolysis. High cost of cellulase has prompted research to explore techniques that can prevent from enzyme deactivation. Colloidal proteins of casein can form monolayers on hydrophobic surfaces that alleviate the de-activation of protein of interest. Scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), capillary electrophoresis (CE), and Kjeldahl and BSA protein assays were used to investigate the unknown mechanism of action of induced cellulase activity during hydrolysis of casein-treated biomass. Adsorption of casein to biomass was observed with all of the analytical techniques used and varied depending on the pretreatment techniques of biomass. FT-IR analysis of amides I and II suggested that the substructure of protein from casein or skim milk were deformed at the time of contact with biomass. With no additive, the majority of one of the cellulase mono-component, 97.1 ± 1.1, was adsorbed to CS within 24 h, this adsorption was irreversible and increased by 2% after 72 h. However, biomass treatment with skim-milk and casein reduced the adsorption to 32.9% ± 6.0 and 82.8% ± 6.0, respectively.

  18. Analysis of Casein Biopolymers Adsorption to Lignocellulosic Biomass as a Potential Cellulase Stabilizer

    Directory of Open Access Journals (Sweden)

    Anahita Dehkhoda Eckard

    2012-01-01

    Full Text Available Although lignocellulosic materials have a good potential to substitute current feedstocks used for ethanol production, conversion of these materials to fermentable sugars is still not economical through enzymatic hydrolysis. High cost of cellulase has prompted research to explore techniques that can prevent from enzyme deactivation. Colloidal proteins of casein can form monolayers on hydrophobic surfaces that alleviate the de-activation of protein of interest. Scanning electron microscope (SEM, fourier transform infrared spectroscopy (FT-IR, capillary electrophoresis (CE, and Kjeldahl and BSA protein assays were used to investigate the unknown mechanism of action of induced cellulase activity during hydrolysis of casein-treated biomass. Adsorption of casein to biomass was observed with all of the analytical techniques used and varied depending on the pretreatment techniques of biomass. FT-IR analysis of amides I and II suggested that the substructure of protein from casein or skim milk were deformed at the time of contact with biomass. With no additive, the majority of one of the cellulase mono-component, 97.1 ± 1.1, was adsorbed to CS within 24 h, this adsorption was irreversible and increased by 2% after 72 h. However, biomass treatment with skim-milk and casein reduced the adsorption to 32.9% ± 6.0 and 82.8% ± 6.0, respectively.

  19. Juvenile hormone prevents 20-hydroxyecdysone-induced metamorphosis by regulating the phosphorylation of a newly identified broad protein.

    Science.gov (United States)

    Cai, Mei-Juan; Liu, Wen; Pei, Xu-Yang; Li, Xiang-Ru; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2014-09-19

    The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis. By contrast, juvenile hormone (JH) prevents metamorphosis. However, the mechanism by which JH inhibits metamorphosis remains unclear. In this study, we propose that JH induces the phosphorylation of Broad isoform Z7 (BrZ7), a newly identified protein, to inhibit 20E-mediated metamorphosis in the lepidopteran insect Helicoverpa armigera. The knockdown of BrZ7 in larvae inhibited metamorphosis by repressing the expression of the 20E response gene. BrZ7 was weakly expressed and phosphorylated during larval growth but highly expressed and non-phosphorylated during metamorphosis. JH regulated the rapid phosphorylation of BrZ7 via a G-protein-coupled receptor-, phospholipase C-, and protein kinase C-triggered pathway. The phosphorylated BrZ7 bound to the 5'-regulatory region of calponin to regulate its expression in the JH pathway. Exogenous JH induced BrZ7 phosphorylation to prevent metamorphosis by suppressing 20E-related gene transcription. JH promoted non-phosphorylated calponin interacting with ultraspiracle protein to activate the JH pathway and antagonize the 20E pathway. This study reveals one of the possible mechanisms by which JH counteracts 20E-regulated metamorphosis by inducing the phosphorylation of BrZ7. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Juvenile Hormone Prevents 20-Hydroxyecdysone-induced Metamorphosis by Regulating the Phosphorylation of a Newly Identified Broad Protein*

    Science.gov (United States)

    Cai, Mei-Juan; Liu, Wen; Pei, Xu-Yang; Li, Xiang-Ru; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2014-01-01

    The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis. By contrast, juvenile hormone (JH) prevents metamorphosis. However, the mechanism by which JH inhibits metamorphosis remains unclear. In this study, we propose that JH induces the phosphorylation of Broad isoform Z7 (BrZ7), a newly identified protein, to inhibit 20E-mediated metamorphosis in the lepidopteran insect Helicoverpa armigera. The knockdown of BrZ7 in larvae inhibited metamorphosis by repressing the expression of the 20E response gene. BrZ7 was weakly expressed and phosphorylated during larval growth but highly expressed and non-phosphorylated during metamorphosis. JH regulated the rapid phosphorylation of BrZ7 via a G-protein-coupled receptor-, phospholipase C-, and protein kinase C-triggered pathway. The phosphorylated BrZ7 bound to the 5′-regulatory region of calponin to regulate its expression in the JH pathway. Exogenous JH induced BrZ7 phosphorylation to prevent metamorphosis by suppressing 20E-related gene transcription. JH promoted non-phosphorylated calponin interacting with ultraspiracle protein to activate the JH pathway and antagonize the 20E pathway. This study reveals one of the possible mechanisms by which JH counteracts 20E-regulated metamorphosis by inducing the phosphorylation of BrZ7. PMID:25096576

  1. Vaccination via Chloroplast Genetics: Affordable Protein Drugs for the Prevention and Treatment of Inherited or Infectious Human Diseases.

    Science.gov (United States)

    Daniell, Henry; Chan, Hui-Ting; Pasoreck, Elise K

    2016-11-23

    Plastid-made biopharmaceuticals treat major metabolic or genetic disorders, including Alzheimer's, diabetes, hypertension, hemophilia, and retinopathy. Booster vaccines made in chloroplasts prevent global infectious diseases, such as tuberculosis, malaria, cholera, and polio, and biological threats, such as anthrax and plague. Recent advances in this field include commercial-scale production of human therapeutic proteins in FDA-approved cGMP facilities, development of tags to deliver protein drugs to targeted human cells or tissues, methods to deliver precise doses, and long-term stability of protein drugs at ambient temperature, maintaining their efficacy. Codon optimization utilizing valuable information from sequenced chloroplast genomes enhanced expression of eukaryotic human or viral genes in chloroplasts and offered unique insights into translation in chloroplasts. Support from major biopharmaceutical companies, development of hydroponic production systems, and evaluation by regulatory agencies, including the CDC, FDA, and USDA, augur well for advancing this novel concept to the clinic and revolutionizing affordable healthcare.

  2. Prevention and reversal of hepatic steatosis with a high-protein diet in mice

    NARCIS (Netherlands)

    Garcia-Caraballo, Sonia C.; Comhair, Tine M.; Verheyen, Fons; Gaemers, Ingrid; Schaap, Frank G.; Houten, Sander M.; Hakvoort, Theodorus B. M.; Dejong, Cornelis H. C.; Lamers, Wouter H.; Koehler, S. Eleonore

    2013-01-01

    The hallmark of NAFLD is steatosis of unknown etiology. We tested the effect of a high-protein (HP)(2) diet on diet-induced steatosis in male C57BL/6 mice with and without pre-existing fatty liver. Mice were fed all combinations of semisynthetic low-fat (LF) or high-fat (HF) and low-protein (LP) or

  3. Arabidopsis protein kinase PKS5 inhibits the plasma membrane H+ -ATPase by preventing interaction with 14-3-3 protein

    DEFF Research Database (Denmark)

    Fuglsang, Anja Thoe; Guo, Yan; Cuin, Tracey A.

    2007-01-01

    Regulation of the trans-plasma membrane pH gradient is an important part of plant responses to several hormonal and environmental cues, including auxin, blue light, and fungal elicitors. However, little is known about the signaling components that mediate this regulation. Here, we report...... that an Arabidopsis thaliana Ser/Thr protein kinase, PKS5, is a negative regulator of the plasma membrane proton pump (PM Hþ-ATPase). Loss-of-function pks5 mutant plants are more tolerant of high external pH due to extrusion of protons to the extracellular space. PKS5 phosphorylates the PM Hþ-ATPase AHA2 at a novel...

  4. Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  5. The monomeric form of Neisseria DNA mimic protein DMP19 prevents DNA from binding to the histone-like HU protein

    Science.gov (United States)

    Ko, Tzu-Ping; Liao, Yi-Ting; Hsu, Kai-Cheng

    2017-01-01

    DNA mimicry is a direct and effective strategy by which the mimic competes with DNA for the DNA binding sites on other proteins. Until now, only about a dozen proteins have been shown to function via this strategy, including the DNA mimic protein DMP19 from Neisseria meningitides. We have shown previously that DMP19 dimer prevents the operator DNA from binding to the transcription factor NHTF. Here, we provide new evidence that DMP19 monomer can also interact with the Neisseria nucleoid-associated protein HU. Using BS3 crosslinking, gel filtration and isothermal titration calorimetry assays, we found that DMP19 uses its monomeric form to interact with the Neisseria HU dimer. Crosslinking conjugated mass spectrometry was used to investigate the binding mode of DMP19 monomer and HU dimer. Finally, an electrophoretic mobility shift assay (EMSA) confirmed that the DNA binding affinity of HU is affected by DMP19. These results showed that DMP19 is bifunctional in the gene regulation of Neisseria through its variable oligomeric forms. PMID:29220372

  6. Adsorption. What else?

    OpenAIRE

    Rodrigues, Alirio E.

    2012-01-01

    [EN] Chemical Engineering today combines Molecular and Materials Engineerig and Process and Product Engineering (ChE=M2P2). Cyclic adsorptive processes (Simulated Moving Bed –SMB and Pressure Swing Adsorption-PSA) will be discussed for “old” and “new” applications making use of “old” and “new” (MOFs) adsorbent materials. After revisiting my memory as PhD student and the First Brazilian Adsorption meeting I will review the basic concepts involved in adsorption processes and then...

  7. Association of Protein Intake with Bone Mineral Density and Bone Mineral Content among Elderly Women: The OSTPRE Fracture Prevention Study.

    Science.gov (United States)

    Isanejad, M; Sirola, J; Mursu, J; Kröger, H; Tuppurainen, M; Erkkilä, A T

    2017-01-01

    It has been hypothesized that high protein intakes are associated with lower bone mineral content (BMC). Previous studies yield conflicting results and thus far no studies have undertaken the interaction of body mass index (BMI) and physical activity with protein intakes in relation to BMC and bone mineral density (BMD). To evaluate the associations of dietary total protein (TP), animal protein (AP) and plant protein (PP) intakes with BMC and BMD and their changes. We tested also the interactions of protein intake with, obesity (BMI ≤30 vs. >30 kg/m2) and physical activity level (passive vs. active). Design/ Setting: Prospective cohort study (Osteoporosis Risk-Factor and Fracture-Prevention Study). Participants/measures: At the baseline, 554 women aged 65-72 years filled out a 3-day food record and a questionnaire covering data on lifestyle, physical activity, diseases, and medications. Intervention group received calcium 1000 mg/d and cholecalciferol 800 IU for 3 years. Control group received neither supplementation nor placebo. Bone density was measured at baseline and year 3, using dual energy x-ray absorptiometry. Multivariable regression analyses were conducted to examine the associations between protein intake and BMD and BMC. In cross-sectional analyses energy-adjusted TP (P≤0·029) and AP (P≤0·045) but not PP (g/d) were negatively associated with femoral neck (FN) BMD and BMC. Women with TP≥1·2 g/kg/body weight (BW) (Ptrend≤0·009) had lower FN, lumbar spine (LS) and total BMD and BMC. In follow-up analysis, TP (g/kg/BW) was inversely associated with LS BMD and LS BMC. The detrimental associations were stronger in women with BMI30 kg/m2 and physical activity.

  8. Nanocomposited coatings produced by laser-assisted process to prevent silicone hydogels from protein fouling and bacterial contamination

    International Nuclear Information System (INIS)

    Huang, Guobang; Chen, Yi; Zhang, Jin

    2016-01-01

    Graphical abstract: Nanocomposited-coating was deposited on silicone hydrogel by using the matrix-assisted pulsed laser evaporation (MAPLE) process. The ZnO–PEG nanocomposited coating reduces over 50% protein absorption on silicone hydrogel, and can inhibit the bacterial growth efficiently. - Highlights: • We developed a nanocomposited coating to prevent silicone hydrogel from biofouling. • Matrix-assisted pulsed laser evaporation can deposit inorganic–organic nanomaterials. • The designed nanocomposited coating reduces protein absorption by over 50%. • The designed nanocomposited coating shows significant antimicrobial efficiency. - Abstract: Zinc oxide (ZnO) nanoparticles incorporating with polyethylene glycol (PEG) were deposited together on the surface of silicone hydrogel through matrix-assisted pulsed laser evaporation (MAPLE). In this process, frozen nanocomposites (ZnO–PEG) in isopropanol were irradiated under a pulsed Nd:YAG laser at 532 nm for 1 h. Our results indicate that the MAPLE process is able to maintain the chemical backbone of polymer and prevent the nanocomposite coating from contamination. The ZnO–PEG nanocomposited coating reduces over 50% protein absorption on silicone hydrogel. The cytotoxicity study shows that the ZnO–PEG nanocomposites deposited on silicone hydrogels do not impose the toxic effect on mouse NIH/3T3 cells. In addition, MAPLE-deposited ZnO–PEG nanocomposites can inhibit the bacterial growth significantly.

  9. Simple Coatings to Render Polystyrene Protein Resistant

    Directory of Open Access Journals (Sweden)

    Marcelle Hecker

    2018-02-01

    Full Text Available Non-specific protein adsorption is detrimental to the performance of many biomedical devices. Polystyrene is a commonly used material in devices and thin films. Simple reliable surface modification of polystyrene to render it protein resistant is desired in particular for device fabrication and orthogonal functionalisation schemes. This report details modifications carried out on a polystyrene surface to prevent protein adsorption. The trialed surfaces included Pluronic F127 and PLL-g-PEG, adsorbed on polystyrene, using a polydopamine-assisted approach. Quartz crystal microbalance with dissipation (QCM-D results showed only short-term anti-fouling success of the polystyrene surface modified with F127, and the subsequent failure of the polydopamine intermediary layer in improving its stability. In stark contrast, QCM-D analysis proved the success of the polydopamine assisted PLL-g-PEG coating in preventing bovine serum albumin adsorption. This modified surface is equally as protein-rejecting after 24 h in buffer, and thus a promising simple coating for long term protein rejection of polystyrene.

  10. Recombinant factor VIII Fc fusion protein for the prevention and treatment of bleeding in children with severe hemophilia A.

    Science.gov (United States)

    Young, G; Mahlangu, J; Kulkarni, R; Nolan, B; Liesner, R; Pasi, J; Barnes, C; Neelakantan, S; Gambino, G; Cristiano, L M; Pierce, G F; Allen, G

    2015-06-01

    Prophylactic factor replacement, which prevents hemarthroses and thereby reduces the musculoskeletal disease burden in children with hemophilia A, requires frequent intravenous infusions (three to four times weekly). Kids A-LONG was a phase 3 open-label study evaluating the safety, efficacy and pharmacokinetics of a longer-acting factor, recombinant factor VIII Fc fusion protein (rFVIIIFc), in previously treated children with severe hemophilia A (endogenous FVIII level of hemophilia A. © 2015 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.

  11. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  12. Lactococcal Abortive Infection Protein AbiV Interacts Directly with the Phage Protein SaV and Prevents Translation of Phage Proteins

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup; Samson, J.E.; Labrie, S.J.

    2010-01-01

    RNAs and proteins suggested that AbiV blocks the activation of late gene transcription, probably by a general inhibition of translation. Using size exclusion chromatography coupled with on-line static light scattering and refractometry, as well as fluorescence quenching experiments, we also demonstrated that both...

  13. Radioactive nuclide adsorption

    International Nuclear Information System (INIS)

    Fukushima, Kimichika.

    1982-01-01

    Purpose: To improve the efficiency of a radioactive nuclide adsorption device by applying a nickel plating on a nickel plate to render the surface active. Constitution: A capturing device for radioactive nuclide such as manganese 54, cobalt 60, 58 and the like is disposed to the inside of a pipeway provided on the upper portion of fuel assemblies through which liquid sodium as the coolant for LMFBR type reactor is passed. The device comprises a cylindrical adsorption body and spacers. The adsorption body is made of nickel and applied with a nickel plating on the surface thereof. The surface of the adsorption body is unevened to result in disturbance in the coolant and thereby improve the adsorptive efficiency. (Kawakami, Y.)

  14. Deregulated MAPK activity prevents adipocyte differentiation of fibroblasts lacking the retinoblastoma protein

    DEFF Research Database (Denmark)

    Hansen, Jacob B; Petersen, Rasmus K; Jørgensen, Claus

    2002-01-01

    A functional retinoblastoma protein (pRB) is required for adipose conversion of preadipocyte cell lines and primary mouse embryo fibroblasts (MEFs) in response to treatment with standard adipogenic inducers. Interestingly, lack of functional pRB in MEFs was recently linked to elevated Ras activity...

  15. Scientists Grow Therapeutic Protein in Engineered Soya Bean Seeds to Prevent AIDS | Poster

    Science.gov (United States)

    Genetically modified soya beans provide a scalable, low-cost method of producing microbicides that prevent AIDS, a technique sustainable for resource-poor countries where AIDS is spreading rapidly. According to the Joint United Nations Programme on HIV/AIDS, more than 36 million people worldwide are living with HIV. While the number of AIDS-related deaths are decreasing, infection rates are still increasing, specifically in Eastern and Southern Africa.

  16. The lectin from Musa paradisiaca binds with the capsid protein of tobacco mosaic virus and prevents viral infection.

    Science.gov (United States)

    Liu, Xiao-Yu; Li, Huan; Zhang, Wei

    2014-05-04

    It has been demonstrated that the lectin from Musa paradisiaca (BanLec-1) could inhibit the cellular entry of human immunodeficiency virus (HIV). In order to evaluate its effects on tobacco mosaic virus (TMV), the banlec-1 gene was cloned and transformed into Escherichia coli and tobacco, respectively. Recombinant BanLec-1 showed metal ions dependence, and higher thermal and pH stability. Overexpression of banlec-1 in tobacco resulted in decreased leaf size, and higher resistance to TMV infection, which includes reduced TMV cellular entry, more stable chlorophyll contents, and enhanced antioxidant enzymes. BanLec-1 was found to bind directly to the TMV capsid protein in vitro , and to inhibit TMV infection in a dose-dependent manner. In contrast to limited prevention in vivo , purified rBanLec-1 exhibited more significant effects on TMV infection in vitro . Taken together, our study indicated that BanLec-1 could prevent TMV infection in tobacco, probably through the interaction between BanLec-1 and TMV capsid protein.

  17. Replication Protein A (RPA) Phosphorylation Prevents RPA Association with Replication Centers

    OpenAIRE

    Vassin, Vitaly M.; Wold, Marc S.; Borowiec, James A.

    2004-01-01

    Mammalian replication protein A (RPA) undergoes DNA damage-dependent phosphorylation at numerous sites on the N terminus of the RPA2 subunit. To understand the functional significance of RPA phosphorylation, we expressed RPA2 variants in which the phosphorylation sites were converted to aspartate (RPA2D) or alanine (RPA2A). Although RPA2D was incorporated into RPA heterotrimers and supported simian virus 40 DNA replication in vitro, the RPA2D mutant was selectively unable to associate with re...

  18. Catalase activity prevents exercise-induced up-regulation of vasoprotective proteins in venous tissue

    OpenAIRE

    Dao, Vu Thao-Vi; Floeren, Melanie; Kumpf, Stephanie; Both, Charlotte; Peter, B?rbel; Balz, Vera; Suvorava, Tatsiana; Kojda, Georg

    2011-01-01

    Abstract Physical activity induces favourable changes of arterial gene expression and protein activity, although little is known about its effect in venous tissue. Although our understanding of the initiating molecular signals is still incomplete, increased expression of endothelial nitric oxide synthase (eNOS) is considered a key event. This study sought to investigate the effects of two different training protocols on the expression of eNOS and extracellular superoxide dismutase (ecSOD) in ...

  19. FTO genotype, dietary protein, and change in appetite: the Preventing Overweight Using Novel Dietary Strategies trial123

    Science.gov (United States)

    Huang, Tao; Li, Yanping; Hu, Frank B; Bray, George A; Sacks, Frank M; Williamson, Donald A; Qi, Lu

    2014-01-01

    Background: A common obesity-risk variant rs9939609 in the fat mass– and obesity-associated (FTO) gene was recently shown to affect appetite, and the gene is sensitive to the regulation of amino acids. Objective: We examined the interaction between FTO genotype and protein intake on the long-term changes in appetite in a randomized controlled trial. Design: We genotyped FTO rs9939609 in 737 overweight adults in the 2-y Preventing Overweight Using Novel Dietary Strategies trial and assessed 4 appetite-related traits including cravings, fullness, hunger, and prospective consumption. Results: We showed that dietary protein significantly modified genetic effects on changes in food cravings and appetite scores at 6 mo after adjustment for age, sex, ethnicity, baseline body mass index, weight change, and baseline value for respective outcomes (P-interaction = 0.027 and 0.048, respectively). The A allele was associated with a greater decrease in food cravings and appetite scores in participants with high-protein–diet intake (P = 0.027 and 0.047, respectively) but not in subjects in the low-protein–diet group (P = 0.384 and 0.078, respectively). The weight regain from 6 to 24 mo attenuated gene-protein interactions. Protein intakes did not modify FTO genotype effects on other appetite measures. Conclusion: Our data suggest that individuals with the FTO rs9939609 A allele might obtain more benefits in a reduction of food cravings and appetite by choosing a hypocaloric and higher-protein weight-loss diet. This trial was registered at clinicaltrials.gov as NCT00072995. PMID:24622803

  20. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    Directory of Open Access Journals (Sweden)

    Qing Chen

    2017-01-01

    Full Text Available Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.

  1. Ultra Structural Characterisation of Tetherin - a Protein Capable of Preventing Viral Release from the Plasma Membrane

    Directory of Open Access Journals (Sweden)

    Ravindra K. Gupta

    2010-04-01

    Full Text Available Tetherin is an antiviral restriction factor made by mammalian cells to protect them from viral infection. It prevents newly formed virus particles from leaving infected cells. Its antiviral mechanism appears to be remarkably uncomplicated. In 2 studies published in PLoS Pathogens electron microscopy is used to support the hypothesis that the tethers that link HIV-1 virions to tetherin expressing cells contain tetherin and are likely to contain tetherin alone. They also show that the HIV-1 encoded tetherin antagonist that is known to cause tetherin degradation, Vpu, serves to reduce the amount of tetherin in the particles thereby allowing their release.

  2. Adsorption of Insecticidal Crystal Protein Cry11Aa onto Nano-Mg(OH)2: Effects on Bioactivity and Anti-Ultraviolet Ability.

    Science.gov (United States)

    Pan, Xiaohong; Xu, Zhangyan; Li, Lan; Shao, Enshi; Chen, Saili; Huang, Tengzhou; Chen, Zhi; Rao, Wenhua; Huang, Tianpei; Zhang, Lingling; Wu, Songqing; Guan, Xiong

    2017-11-01

    The traditional Bacillus thuringiensis (Bt) formulations for field applications are not resistant to harsh environmental conditions. Hence, the active ingredients of the Bt bioinsecticides could degrade quickly and has low anti-ultraviolet ability in the field, which significantly limits its practical application. In the present study, we developed an efficient and stable delivery system for Bt Cry11Aa toxins. We coated Cry11Aa proteins with Mg(OH) 2 nanoparticles (MHNPs), and then assessed the effects of MHNPs on bioactivity and anti-ultraviolet ability of the Cry11Aa proteins. Our results indicated that MHNPs, like "coating clothes", could effectively protect the Cry protein and enhance the insecticidal bioactivity after UV radiation (the degradation rate was decreased from 64.29% to 16.67%). In addtion, MHNPs could improve the proteolysis of Cry11Aa in the midgut and aggravate the damage of the Cry protein to the gut epithelial cells, leading to increased insecticidal activity against Culex quinquefasciatus. Our results revealed that MHNPs, as an excellent nanocarrier, could substantially improve the insecticidal bioactivity and anti-ultraviolet ability of Cry11Aa.

  3. Galectin-1 Protein Therapy Prevents Pathology and Improves Muscle Function in the mdx Mouse Model of Duchenne Muscular Dystrophy.

    Science.gov (United States)

    Van Ry, Pam M; Wuebbles, Ryan D; Key, Megan; Burkin, Dean J

    2015-08-01

    Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease caused by mutations in the dystrophin gene, leading to the loss of a critical component of the sarcolemmal dystrophin glycoprotein complex. Galectin-1 is a small 14 kDa protein normally found in skeletal muscle and has been shown to be a modifier of immune response, muscle repair, and apoptosis. Galectin-1 levels are elevated in the muscle of mouse and dog models of DMD. Together, these findings led us to hypothesize that Galectin-1 may serve as a modifier of disease progression in DMD. To test this hypothesis, recombinant mouse Galectin-1 was produced and used to treat myogenic cells and the mdx mouse model of DMD. Here we show that intramuscular and intraperitoneal injections of Galectin-1 into mdx mice prevented pathology and improved muscle function in skeletal muscle. These improvements were a result of enhanced sarcolemmal stability mediated by elevated utrophin and α7β1 integrin protein levels. Together our results demonstrate for the first time that Galectin-1 may serve as an exciting new protein therapeutic for the treatment of DMD.

  4. adsorption, eosin, humic, peat

    OpenAIRE

    anshar, andi muhammad

    2015-01-01

    Eosin is one of the dyes commonly used in the industry and has the potential to cause pollution of the water environment. The Eosin pollution treatment methods used in this study was the adsorption method using humin fraction obtained from the peat land comes from Kalimantan. From the research data showed that the adsorption of eosin in humin result of washing with HCl / HF optimum at pH 4 and a contact time of 60 minutes with the adsorption-order rate was 8,4 x 10-3 min-1

  5. The fission yeast CENP-B protein Abp1 prevents pervasive transcription of repetitive DNA elements.

    Science.gov (United States)

    Daulny, Anne; Mejía-Ramírez, Eva; Reina, Oscar; Rosado-Lugo, Jesus; Aguilar-Arnal, Lorena; Auer, Herbert; Zaratiegui, Mikel; Azorin, Fernando

    2016-10-01

    It is well established that eukaryotic genomes are pervasively transcribed producing cryptic unstable transcripts (CUTs). However, the mechanisms regulating pervasive transcription are not well understood. Here, we report that the fission yeast CENP-B homolog Abp1 plays an important role in preventing pervasive transcription. We show that loss of abp1 results in the accumulation of CUTs, which are targeted for degradation by the exosome pathway. These CUTs originate from different types of genomic features, but the highest increase corresponds to Tf2 retrotransposons and rDNA repeats, where they map along the entire elements. In the absence of abp1, increased RNAPII-Ser5P occupancy is observed throughout the Tf2 coding region and, unexpectedly, RNAPII-Ser5P is enriched at rDNA repeats. Loss of abp1 also results in Tf2 derepression and increased nucleolus size. Altogether these results suggest that Abp1 prevents pervasive RNAPII transcription of repetitive DNA elements (i.e., Tf2 and rDNA repeats) from internal cryptic sites. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Thioredoxin-albumin fusion protein prevents copper enhanced zinc-induced neurotoxicity via its antioxidative activity.

    Science.gov (United States)

    Tanaka, Ken-Ichiro; Shimoda, Mikako; Chuang, Victor T G; Nishida, Kento; Kawahara, Masahiro; Ishida, Tatsuhiro; Otagiri, Masaki; Maruyama, Toru; Ishima, Yu

    2018-01-15

    Zinc (Zn) is a co-factor for a vast number of enzymes, and functions as a regulator for immune mechanism and protein synthesis. However, excessive Zn release induced in pathological situations such as stroke or transient global ischemia is toxic. Previously, we demonstrated that the interaction of Zn and copper (Cu) is involved in the pathogenesis of Alzheimer's disease and vascular dementia. Furthermore, oxidative stress has been shown to play a significant role in the pathogenesis of various metal ions induced neuronal death. Thioredoxin-Albumin fusion (HSA-Trx) is a derivative of thioredoxin (Trx), an antioxidative protein, with improved plasma retention and stability of Trx. In this study, we examined the effect of HSA-Trx on Cu 2+ /Zn 2+ -induced neurotoxicity. Firstly, HSA-Trx was found to clearly suppress Cu 2+ /Zn 2+ -induced neuronal cell death in mouse hypothalamic neuronal cells (GT1-7 cells). Moreover, HSA-Trx markedly suppressed Cu 2+ /Zn 2+ -induced ROS production and the expression of oxidative stress related genes, such as heme oxygenase-1. In contrast, HSA-Trx did not affect the intracellular levels of both Cu 2+ and Zn 2+ after Cu 2+ /Zn 2+ treatment. Finally, HSA-Trx was found to significantly suppress endoplasmic reticulum (ER) stress response induced by Cu 2+ /Zn 2+ treatment in a dose dependent manner. These results suggest that HSA-Trx counteracted Cu 2+ /Zn 2+ -induced neurotoxicity by suppressing the production of ROS via interfering the related gene expressions, in addition to the highly possible radical scavenging activity of the fusion protein. Based on these findings, HSA-Trx has great potential as a promising therapeutic agent for the treatment of refractory neurological diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. An Alternative Form of Replication Protein A Prevents Viral Replication in Vitro*

    OpenAIRE

    Mason, Aaron C.; Haring, Stuart J.; Pryor, John M.; Staloch, Cathy A.; Gan, Tze Fei; Wold, Marc S.

    2009-01-01

    Replication protein A (RPA), the eukaryotic single-stranded DNA-binding complex, is essential for multiple processes in cellular DNA metabolism. The “canonical” RPA is composed of three subunits (RPA1, RPA2, and RPA3); however, there is a human homolog to the RPA2 subunit, called RPA4, that can substitute for RPA2 in complex formation. We demonstrate that the resulting “alternative” RPA (aRPA) complex has solution and DNA binding properties indistinguishable from the c...

  8. Mitogen activated protein kinase phosphatase-1 prevents the development of tactile sensitivity in a rodent model of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Ndong Christian

    2012-04-01

    Full Text Available Abstract Background Neuropathic pain due to nerve injury is one of the most difficult types of pain to treat. Following peripheral nerve injury, neuronal and glial plastic changes contribute to central sensitization and perpetuation of mechanical hypersensitivity in rodents. The mitogen activated protein kinase (MAPK family is pivotal in this spinal cord plasticity. MAPK phosphatases (MKPs limit inflammatory processes by dephosphorylating MAPKs. For example, MKP-1 preferentially dephosphorylates p-p38. Since spinal p-p38 is pivotal for the development of chronic hypersensitivity in rodent models of pain, and p-p38 inhibitors have shown clinical potential in acute and chronic pain patients, we hypothesize that induction of spinal MKP-1 will prevent the development of peripheral nerve-injury-induced hypersensitivity and p-p38 overexpression. Results We cloned rat spinal cord MKP-1 and optimize MKP-1 cDNA in vitro using transfections to BV-2 cells. We observed that in vitro overexpression of MKP-1 blocked lipopolysaccharide-induced phosphorylation of p38 (and other MAPKs as well as release of pro-algesic effectors (i.e., cytokines, chemokines, nitric oxide. Using this cDNA MKP-1 and a non-viral, in vivo nanoparticle transfection approach, we found that spinal cord overexpression of MKP-1 prevented development of peripheral nerve-injury-induced tactile hypersensitivity and reduced pro-inflammatory cytokines and chemokines and the phosphorylated form of p38. Conclusions Our results indicate that MKP-1, the natural regulator of p-p38, mediates resolution of the spinal cord pro-inflammatory milieu induced by peripheral nerve injury, resulting in prevention of chronic mechanical hypersensitivity. We propose that MKP-1 is a potential therapeutic target for pain treatment or prevention.

  9. CSL protein regulates transcription of genes required to prevent catastrophic mitosis in fission yeast.

    Science.gov (United States)

    Převorovský, Martin; Oravcová, Martina; Zach, Róbert; Jordáková, Anna; Bähler, Jürg; Půta, František; Folk, Petr

    2016-11-16

    For every eukaryotic cell to grow and divide, intricately coordinated action of numerous proteins is required to ensure proper cell-cycle progression. The fission yeast Schizosaccharomyces pombe has been instrumental in elucidating the fundamental principles of cell-cycle control. Mutations in S. pombe 'cut' (cell untimely torn) genes cause failed coordination between cell and nuclear division, resulting in catastrophic mitosis. Deletion of cbf11, a fission yeast CSL transcription factor gene, triggers a 'cut' phenotype, but the precise role of Cbf11 in promoting mitotic fidelity is not known. We report that Cbf11 directly activates the transcription of the acetyl-coenzyme A carboxylase gene cut6, and the biotin uptake/biosynthesis genes vht1 and bio2, with the former 2 implicated in mitotic fidelity. Cbf11 binds to a canonical, metazoan-like CSL response element (GTGGGAA) in the cut6 promoter. Expression of Cbf11 target genes shows apparent oscillations during the cell cycle using temperature-sensitive cdc25-22 and cdc10-M17 block-release experiments, but not with other synchronization methods. The penetrance of catastrophic mitosis in cbf11 and cut6 mutants is nutrient-dependent. We also show that drastic decrease in biotin availability arrests cell proliferation but does not cause mitotic defects. Taken together, our results raise the possibility that CSL proteins play conserved roles in regulating cell-cycle progression, and they could guide experiments into mitotic CSL functions in mammals.

  10. Vitamin A, Cancer Treatment and Prevention: The New Role of Cellular Retinol Binding Proteins

    Directory of Open Access Journals (Sweden)

    Elena Doldo

    2015-01-01

    Full Text Available Retinol and vitamin A derivatives influence cell differentiation, proliferation, and apoptosis and play an important physiologic role in a wide range of biological processes. Retinol is obtained from foods of animal origin. Retinol derivatives are fundamental for vision, while retinoic acid is essential for skin and bone growth. Intracellular retinoid bioavailability is regulated by the presence of specific cytoplasmic retinol and retinoic acid binding proteins (CRBPs and CRABPs. CRBP-1, the most diffuse CRBP isoform, is a small 15 KDa cytosolic protein widely expressed and evolutionarily conserved in many tissues. CRBP-1 acts as chaperone and regulates the uptake, subsequent esterification, and bioavailability of retinol. CRBP-1 plays a major role in wound healing and arterial tissue remodelling processes. In the last years, the role of CRBP-1-related retinoid signalling during cancer progression became object of several studies. CRBP-1 downregulation associates with a more malignant phenotype in breast, ovarian, and nasopharyngeal cancers. Reexpression of CRBP-1 increased retinol sensitivity and reduced viability of ovarian cancer cells in vitro. Further studies are needed to explore new therapeutic strategies aimed at restoring CRBP-1-mediated intracellular retinol trafficking and the meaning of CRBP-1 expression in cancer patients’ screening for a more personalized and efficacy retinoid therapy.

  11. Polyglycerol coatings of glass vials for protein resistance.

    Science.gov (United States)

    Höger, Kerstin; Becherer, Tobias; Qiang, Wei; Haag, Rainer; Friess, Wolfgang; Küchler, Sarah

    2013-11-01

    Proteins are surface active molecules which undergo non-specific adsorption when getting in contact with surfaces such as the primary packaging material. This process is critical as it may cause a loss of protein content or protein aggregation. To prevent unspecific adsorption, protein repellent coatings are of high interest. We describe the coating of industrial relevant borosilicate glass vials with linear methoxylated polyglycerol, hyperbranched polyglycerol, and hyperbranched methoxylated polyglycerol. All coatings provide excellent protein repellent effects. The hyperbranched, non-methoxylated coating performed best. The protein repellent properties were maintained also after applying industrial relevant sterilization methods (≥200 °C). Marginal differences in antibody stability between formulations stored in bare glass vials and coated vials were detected after 3 months storage; the protein repellent effect remained largely stable. Here, we describe a new material suitable for the coating of primary packaging material of proteins which significantly reduces the protein adsorption and thus could present an interesting new possibility for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Abscisic acid and osmoticum prevent germination of developing alfalfa embryos, but only osmoticum maintains the synthesis of developmental proteins.

    Science.gov (United States)

    Xu, N; Coulter, K M; Derek Bewley, J

    1990-10-01

    Developing seeds of alfalfa (Medicago sativa L.) acquire the ability to germinate during the latter stages of development, the maturation drying phase. Isolated embryos placed on Murashige and Skoog medium germinate well during early and late development, but poorly during mid-development; however, when placed on water they germinate well only during the latter stage of development. Germination of isolated embryos is very slow and poor when they are incubated in the presence of surrounding seed structures (the endosperm or seed coat) taken from the mid-development stages. This inhibitory effect is also achieved by incubating embryos in 10(-5) M abscisic acid (ABA). Endogenous ABA attains a high level during mid-development, especially in the endosperm. Seeds developing in pods treated with fluridone (1-methyl-3-phenyl-5[3-(trifluoromethyl)-phenyl]-4(1H)-pyridinone) contain low levels of ABA during mid-development, and the endosperm and seed coat only weakly inhibit the germination of isolated embryos. However, intact seeds from fluridone-treated pods do not germinate viviparously, which is indicative that ABA alone is not responsible for maintaining seeds in a developing state. Application of osmoticum (e.g. 0.35 M sucrose) to isolated developing embryos prevents their germination. Also, in the developing seed in situ the osmotic potential is high. Thus internal levels of osmoticum may play a role in preventing germination of the embryo and maintaining development. Abscisic acid and osmoticum impart distinctly different metabolic responses on developing embryos, as demonstrated by their protein-synthetic capacity. Only in the presence of osmoticum do embryos synthesize proteins which are distinctly recognizable as those synthesized by developing embryos in situ, i.e. when inside the pod. Abscisic acid induces the synthesis of a few unique proteins, but these arise even in mature embryos treated with ABA. Thus while both osmoticum and ABA prevent precocious

  13. A Neospora caninum vaccine using recombinant proteins fails to prevent foetal infection in pregnant cattle after experimental intravenous challenge.

    Science.gov (United States)

    Hecker, Yanina P; Cóceres, Verónica; Wilkowsky, Silvina E; Jaramillo Ortiz, José M; Morrell, Eleonora L; Verna, Andrea E; Ganuza, Agustina; Cano, Dora B; Lischinsky, Lilian; Angel, Sergio O; Zamorano, Patricia; Odeón, Anselmo C; Leunda, María R; Campero, Carlos M; Morein, Bror; Moore, Dadín P

    2014-12-15

    The aim of the present study was to evaluate the immunogenicity and protective efficacy of rNcSAG1, rNcHSP20 and rNcGRA7 recombinant proteins formulated with immune stimulating complexes (ISCOMs) in pregnant heifers against vertical transmission of Neospora caninum. Twelve pregnant heifers were divided into 3 groups of 4 heifers each, receiving different formulations before mating. Immunogens were administered twice subcutaneously: group A animals were inoculated with three recombinant proteins (rNcSAG1, rNcHSP20, rNcGRA7) formulated with ISCOMs; group B animals received ISCOM-MATRIX (without antigen) and group C received sterile phosphate-buffered saline (PBS) only. The recombinant proteins were expressed in Escherichia coli and purified nickel resin. All groups were intravenously challenged with the NC-1 strain of N. caninum at Day 70 of gestation and dams slaughtered at week 17 of the experiment. Heifers from group A developed specific antibodies against rNcSAG1, rNcHSP20 and rNcGRA7 prior to the challenge. Following immunization, an statistically significant increase of antibodies against rNcSAG1 and rNcHSP20 in all animals of group A was detected compared to animals in groups B and C at weeks 5, 13 and 16 (P0.001). There were no differences in IFN-γ production among the experimental groups at any time point (P>0.05). Transplacental transmission was determined in all foetuses of groups A, B and C by Western blot, immunohistochemistry and nested PCR. This work showed that rNcSAG1, rNcHSP20 and rNcGRA7 proteins while immunogenic in cattle failed to prevent the foetal infection in pregnant cattle challenged at Day 70 of gestation. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  15. Co adsorption in kaolinite

    International Nuclear Information System (INIS)

    Souza, Eliel S.; Silva, Paulo S.C.

    2017-01-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  16. Co adsorption in kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Eliel S.; Silva, Paulo S.C., E-mail: eliel201019@hotmail.com, E-mail: pscsilva@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  17. LRRK2 kinase inhibition prevents pathological microglial phagocytosis in response to HIV-1 Tat protein

    Directory of Open Access Journals (Sweden)

    Marker Daniel F

    2012-11-01

    Full Text Available Abstract Background Human Immunodeficiency Virus-1 (HIV-1 associated neurocognitive disorders (HANDs are accompanied by significant morbidity, which persists despite the use of combined antiretroviral therapy (cART. While activated microglia play a role in pathogenesis, changes in their immune effector functions, including phagocytosis and proinflammatory signaling pathways, are not well understood. We have identified leucine-rich repeat kinase 2 (LRRK2 as a novel regulator of microglial phagocytosis and activation in an in vitro model of HANDs, and hypothesize that LRRK2 kinase inhibition will attenuate microglial activation during HANDs. Methods We treated BV-2 immortalized mouse microglia cells with the HIV-1 trans activator of transcription (Tat protein in the absence or presence of LRRK2 kinase inhibitor (LRRK2i. We used Western blot, qRT-PCR, immunocytochemistry and latex bead engulfment assays to analyze LRRK2 protein levels, proinflammatory cytokine and phagocytosis receptor expression, LRRK2 cellular distribution and phagocytosis, respectively. Finally, we utilized ex vivo microfluidic chambers containing primary hippocampal neurons and BV-2 microglia cells to investigate microglial phagocytosis of neuronal axons. Results We found that Tat-treatment of BV-2 cells induced kinase activity associated phosphorylation of serine 935 on LRRK2 and caused the formation of cytoplasmic LRRK2 inclusions. LRRK2i decreased Tat-induced phosphorylation of serine 935 on LRRK2 and inhibited the formation of Tat-induced cytoplasmic LRRK2 inclusions. LRRK2i also decreased Tat-induced process extension in BV-2 cells. Furthermore, LRRK2i attenuated Tat-induced cytokine expression and latex bead engulfment. We examined relevant cellular targets in microfluidic chambers and found that Tat-treated BV-2 microglia cells cleared axonal arbor and engulfed neuronal elements, whereas saline treated controls did not. LRRK2i was found to protect axons in the presence

  18. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    1997-01-01

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...... structure to the next. We propose a model to explain this behavior, and use it to discuss more generally the origin of structure sensitivity in heterogeneous catalysis....

  19. A naturally occurring variant of the human prion protein completely prevents prion disease.

    Science.gov (United States)

    Asante, Emmanuel A; Smidak, Michelle; Grimshaw, Andrew; Houghton, Richard; Tomlinson, Andrew; Jeelani, Asif; Jakubcova, Tatiana; Hamdan, Shyma; Richard-Londt, Angela; Linehan, Jacqueline M; Brandner, Sebastian; Alpers, Michael; Whitfield, Jerome; Mead, Simon; Wadsworth, Jonathan D F; Collinge, John

    2015-06-25

    Mammalian prions, transmissible agents causing lethal neurodegenerative diseases, are composed of assemblies of misfolded cellular prion protein (PrP). A novel PrP variant, G127V, was under positive evolutionary selection during the epidemic of kuru--an acquired prion disease epidemic of the Fore population in Papua New Guinea--and appeared to provide strong protection against disease in the heterozygous state. Here we have investigated the protective role of this variant and its interaction with the common, worldwide M129V PrP polymorphism. V127 was seen exclusively on a M129 PRNP allele. We demonstrate that transgenic mice expressing both variant and wild-type human PrP are completely resistant to both kuru and classical Creutzfeldt-Jakob disease (CJD) prions (which are closely similar) but can be infected with variant CJD prions, a human prion strain resulting from exposure to bovine spongiform encephalopathy prions to which the Fore were not exposed. Notably, mice expressing only PrP V127 were completely resistant to all prion strains, demonstrating a different molecular mechanism to M129V, which provides its relative protection against classical CJD and kuru in the heterozygous state. Indeed, this single amino acid substitution (G→V) at a residue invariant in vertebrate evolution is as protective as deletion of the protein. Further study in transgenic mice expressing different ratios of variant and wild-type PrP indicates that not only is PrP V127 completely refractory to prion conversion but acts as a potent dose-dependent inhibitor of wild-type prion propagation.

  20. Antifouling coatings: recent developments in the design of surfaces that prevent fouling by proteins, bacteria, and marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Indrani; Pangule, Ravindra C.; Kane, Ravi S. [Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Ricketts Building, Troy, NY 12180 (United States)

    2011-02-08

    The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Immunization with FSHβ fusion protein antigen prevents bone loss in a rat ovariectomy-induced osteoporosis model

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Wenxin; Yan, Xingrong; Du, Huicong; Cui, Jihong; Li, Liwen, E-mail: liven@nwu.edu.cn; Chen, Fulin, E-mail: chenfl@nwu.edu.cn

    2013-05-03

    Highlights: •A GST-FSH fusion protein was successfully expressed in E. coli. •Immunization with GST-FSH antigen can raise high-titer anti-FSH polyclonal sera. •Anti-FSH polyclonal sera can neutralize osteoclastogenic effect of FSH in vitro. •FSH immunization can prevent bone loss in a rat osteoporosis model. -- Abstract: Osteoporosis, a metabolic bone disease, threatens postmenopausal women globally. Hormone replacement therapy (HTR), especially estrogen replacement therapy (ERT), is used widely in the clinic because it has been generally accepted that postmenopausal osteoporosis is caused by estrogen deficiency. However, hypogonadal α and β estrogen receptor null mice were only mildly osteopenic, and mice with either receptor deleted had normal bone mass, indicating that estrogen may not be the only mediator that induces osteoporosis. Recently, follicle-stimulating hormone (FSH), the serum concentration of which increases from the very beginning of menopause, has been found to play a key role in postmenopausal osteoporosis by promoting osteoclastogenesis. In this article, we confirmed that exogenous FSH can enhance osteoclast differentiation in vitro and that this effect can be neutralized by either an anti-FSH monoclonal antibody or anti-FSH polyclonal sera raised by immunizing animals with a recombinant GST-FSHβ fusion protein antigen. Moreover, immunizing ovariectomized rats with the GST-FSHβ antigen does significantly prevent trabecular bone loss and thereby enhance the bone strength, indicating that a FSH-based vaccine may be a promising therapeutic strategy to slow down bone loss in postmenopausal women.

  2. Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces.

    Science.gov (United States)

    Secker, T J; Pinchin, H E; Hervé, R C; Keevil, C W

    2015-01-01

    Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.

  3. Albumin adsorption on oxide thin films studied by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Bermudez, P., E-mail: suriel21@yahoo.com [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, C.U., 04510, Mexico D.F. (Mexico); Unidad de Posgrado, Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, CU, 04510, Mexico D.F. (Mexico); Rodil, S.E.; Muhl, S. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, C.U., 04510, Mexico D.F. (Mexico)

    2011-12-15

    Thin films of tantalum, niobium, zirconium and titanium oxides were deposited by reactive magnetron sputtering and their wettability and surface energy, optical properties, roughness, chemical composition and microstructure were characterized using contact angle measurements, spectroscopic ellipsometry, profilometry, X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The purpose of the work was to correlate the surface properties of the films to the Bovine Serum Albumin (BSA) adsorption, as a first step into the development of an initial in vitro test of the films biocompatibility, based on standardized protein adsorption essays. The films were immersed into BSA solutions with different protein concentrations and protein adsorption was monitored in situ by dynamic ellipsometry; the adsorption-rate was dependent on the solution concentration and the immersion time. The overall BSA adsorption was studied in situ using spectroscopic ellipsometry and it was found to be influenced by the wettability of the films; larger BSA adsorption occurred on the more hydrophobic surface, the ZrO{sub 2} film. On the Ta{sub 2}O{sub 5}, Nb{sub 2}O{sub 5} and TiO{sub 2} films, hydrophilic surfaces, the overall BSA adsorption increased with the surface roughness or the polar component of the surface energy.

  4. Post-Transcriptional Regulation Prevents Accumulation of Glutathione Reductase Protein and Activity in the Bundle Sheath Cells of Maize1

    Science.gov (United States)

    Pastori, Gabriela M.; Mullineaux, Philip M.; Foyer, Christine H.

    2000-01-01

    Glutathione reductase (GR; EC 1.6.4.2) activity was assayed in bundle sheath and mesophyll cells of maize (Zea mays L. var H99) from plants grown at 20°C, 18°C, and 15°C. The purity of each fraction was determined by measuring the associated activity of the compartment-specific marker enzymes, Rubisco and phosphoenolpyruvate carboxylase, respectively. GR activity and the abundance of GR protein and mRNA increased in plants grown at 15°C and 18°C compared with those grown at 20°C. In all cases GR activity was found only in mesophyll fractions of the leaves, with no GR activity being detectable in bundle sheath extracts. Immunogold labeling with GR-specific antibodies showed that the GR protein was exclusively localized in the mesophyll cells of leaves at all growth temperatures, whereas GR transcripts (as determined by in situ hybridization techniques) were observed in both cell types. These results indicate that post-transcriptional regulation prevents GR accumulation in the bundle sheath cells of maize leaves. The resulting limitation on the capacity for regeneration of reduced glutathione in this compartment may contribute to the extreme chilling sensitivity of maize leaves. PMID:10712529

  5. Adsorption of uranium on halloysite

    International Nuclear Information System (INIS)

    Kilislioglu, A.; Bilgin, B.

    2002-01-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  6. Adsorption of uranium on halloysite

    Energy Technology Data Exchange (ETDEWEB)

    Kilislioglu, A.; Bilgin, B. [Istanbul Univ. (Turkey). Faculty of Engineering

    2002-07-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  7. Facile synthesis and characterisation of AlNs using Protein Rich Solution extracted from sewage sludge and its application for ultrasonic assisted dye adsorption: Isotherms, kinetics, mechanism and RSM design.

    Science.gov (United States)

    Mary Ealias, Anu; Saravanakumar, M P

    2018-01-15

    Protein Rich Solution (PRS) was prepared from the sewage sludge with ultrasonic assistance. With PRS, aluminium based nanosheet like materials (AlNs) were synthesised for the ultrasonic removal of Congo Red (CR) and Crystal Violet (CV) dyes. PRS was characterised by UV, EEM and NMR spectral analysis. AlNs were characterised by FTIR, XRD, TGA, BET, SEM, AFM, TEM and XPS analysis. The point of zero charge of AlNs was found to be 5.4. The BET analysis ensured that the average pore diameter and total pore volume of AlNs as 8.464 nm and 0.11417 cc/g respectively. The efficacy of AlNs for the removal of toxic dyes was tested by performing Response surface methodology (RSM) designed experiments. The effect of sonication time, dosage and initial concentration on dye removal was studied at an optimised pH value. Langmuir, Freundlich and Temkin isotherm models were examined. The maximum adsorption capacity was found to be 121.951 and 105.263 mg/g for CR and CV respectively. The kinetic models like pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion were examined to understand the mechanism behind it. The results revealed that the use of ultrasonication enhanced the mass transfer. The experimental studies on the influence of ultrasound power indicated a positive relation with the removal efficiency. The results of thermodynamic study revealed that the process was spontaneous and exothermic for both the dyes. The increase in ionic strength increased the removal efficiency for both CR and CV. RSM predicted the optimum adsorbent dosages as 0.16 g for 50 mg/L of CR and 0.12 g for 100 mg/L of CV dye solutions. The values of half-life and fractional adsorption for both CR and CV suggested that the low cost AlNs has high potential to remove the toxic industrial dyes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Modeling chromatographic columns. Non-equilibrium packed-bed adsorption with non-linear adsorption isotherms

    NARCIS (Netherlands)

    Özdural, A.R.; Alkan, A.; Kerkhof, P.J.A.M.

    2004-01-01

    In this work a new mathematical model, based on non-equilibrium conditions, describing the dynamic adsorption of proteins in columns packed with spherical adsorbent particles is used to study the performance of chromatographic systems. Simulations of frontal chromatography, including axial

  9. Rosuvastatin for primary prevention among individuals with elevated high-sensitivity c-reactive protein and 5% to 10% and 10% to 20% 10-year risk. Implications of the Justification for Use of Statins in Prevention

    DEFF Research Database (Denmark)

    Ridker, Paul M; Macfadyen, Jean G; Nordestgaard, Børge G

    2010-01-01

    Recent primary prevention guidelines issued in Canada endorse the use of statin therapy among individuals at "intermediate risk" who have elevated levels of high-sensitivity C-reactive protein (hsCRP). However, trial data directly addressing whether this recommendation defines a patient populatio...

  10. Polerovirus protein P0 prevents the assembly of small RNA-containing RISC complexes and leads to degradation of ARGONAUTE1.

    Science.gov (United States)

    Csorba, Tibor; Lózsa, Rita; Hutvágner, György; Burgyán, József

    2010-05-01

    RNA silencing plays an important role in plants in defence against viruses. To overcome this defence, plant viruses encode suppressors of RNA silencing. The most common mode of silencing suppression is sequestration of double-stranded RNAs involved in the antiviral silencing pathways. Viral suppressors can also overcome silencing responses through protein-protein interaction. The poleroviral P0 silencing suppressor protein targets ARGONAUTE (AGO) proteins for degradation. AGO proteins are the core component of the RNA-induced silencing complex (RISC). We found that P0 does not interfere with the slicer activity of pre-programmed siRNA/miRNA containing AGO1, but prevents de novo formation of siRNA/miRNA containing AGO1. We show that the AGO1 protein is part of a high-molecular-weight complex, suggesting the existence of a multi-protein RISC in plants. We propose that P0 prevents RISC assembly by interacting with one of its protein components, thus inhibiting formation of siRNA/miRNA-RISC, and ultimately leading to AGO1 degradation. Our findings also suggest that siRNAs enhance the stability of co-expressed AGO1 in both the presence and absence of P0.

  11. Desorption of Lipases Immobilized on Octyl-Agarose Beads and Coated with Ionic Polymers after Thermal Inactivation. Stronger Adsorption of Polymers/Unfolded Protein Composites

    Directory of Open Access Journals (Sweden)

    Jose J. Virgen-Ortíz

    2017-01-01

    Full Text Available Lipases from Candida antarctica (isoform B and Rhizomucor miehei (CALB and RML have been immobilized on octyl-agarose (OC and further coated with polyethylenimine (PEI and dextran sulfate (DS. The enzymes just immobilized on OC supports could be easily released from the support using 2% SDS at pH 7, both intact or after thermal inactivation (in fact, after inactivation most enzyme molecules were already desorbed. The coating with PEI and DS greatly reduced the enzyme release during thermal inactivation and improved enzyme stability. However, using OC-CALB/RML-PEI-DS, the full release of the immobilized enzyme to reuse the support required more drastic conditions: a pH value of 3, a buffer concentration over 2 M, and temperatures above 45 °C. However, even these conditions were not able to fully release the thermally inactivated enzyme molecules from the support, being necessary to increase the buffer concentration to 4 M sodium phosphate and decrease the pH to 2.5. The formation of unfolded protein/polymers composites seems to be responsible for this strong interaction between the octyl and some anionic groups of OC supports. The support could be reused five cycles using these conditions with similar loading capacity of the support and stability of the immobilized enzyme.

  12. FERMENTED SOYBEAN CAKE AND ALBUMIN FORMULA AS NUTRITIONAL SUPPORT PREVENTS PROTEIN ENERGY MALNUTRITION AND AKI IN STROKE PATIENTS

    Directory of Open Access Journals (Sweden)

    Nanny Djaya

    2012-06-01

    Natrium and Kalium, could be corrected with appropriate nutritional support (adequate calorie, protein and mineral and therefore prevents acute kidney injury and protein energy malnutrition in elderly patients with anorexia.

  13. Adsorption and exhaustion device for gaseoue uranium fluorides

    International Nuclear Information System (INIS)

    Kida, Yasuo; Nakamura, Yuichi.

    1984-01-01

    Purpose: To prevent gaseous uranium fluorides from passing through the adsorption layer upon exhausting the gaseous uranium, fluorides from a uranium fluoride processing facility through adsorption traps, by controlling the flow rate of the gaseous uranium fluorides passing through the layer constant. Constitution: An adsorption trap is connected by way of pipeways to a uranium fluoride processing facility, and a flow rate detector for detecting the flow rate of gaseous uranium fluorides and a pressure gauge for detecting the pressure at the inlet of the adsorption trap are disposed to the pipeways. The setting value for the pressure control is calculated from the detection value of the flow rate detector by the pressure control gage. Then, an operation amount for the pressure control valve is calculated based on the deviatoin between the setting value for the pressure control and the inlet pressure at the adsorption trap. This enables to control the flow rate of the gaseous uranium fluorides passing through the adsorption layer always constant thereby enabling to prevent excess increase in the flow rate which results in damages in the adsorption layer. (Moriyama, K.)

  14. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon

    2013-12-26

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  15. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon; Thu, Kyaw; Amy, Gary; Chunggaze, Mohammed; Al-Ghasham, Tawfiq

    2013-01-01

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  16. Kinetics of the Adsorption of Bovine Serum Albumin of White Wine ...

    African Journals Online (AJOL)

    NJD

    2008-11-07

    Nov 7, 2008 ... surfaces. The protein adsorption capacity of zirconium oxide was observed to ... cases.7 In some, conformational changes occur in the protein molecule ... specific electrostatic attractive force between the negative charges on ...

  17. American Ginseng Stimulates Insulin Production and Prevents Apoptosis through Regulation of Uncoupling Protein-2 in Cultured β Cells

    Directory of Open Access Journals (Sweden)

    John Zeqi Luo

    2006-01-01

    Full Text Available American ginseng root displays the ability to achieve glucose homeostasis both experimentally and clinically but the unknown mechanism used by ginseng to achieve its therapeutic effects on diabetes limits its application. Disruption in the insulin secretion of pancreatic β cells is considered the major cause of diabetes. A mitochondrial protein, uncoupling protein-2 (UCP-2 has been found to play a critical role in insulin synthesis and β cell survival. Our preliminary studies found that the extracts of American ginseng inhibit UCP-2 expression which may contribute to the ability of ginseng protecting β cell death and improving insulin synthesis. Therefore, we hypothesized that ginseng extracts suppress UCP-2 in the mitochondria of pancreatic β cells, promoting insulin synthesis and anti-apoptosis (a programmed cell-death mechanism. To test the hypothesis, the serum-deprived quiescent β cells were cultured with or without interleukin-1β (IL-1β, (200 pg ml−1, a cytokine to induce β cell apoptosis and water extracts of American ginseng (25 μg per 5 μl administered to wells of 0.5 ml culture for 24 h. We evaluated effects of ginseng on UCP-2 expression, insulin production, anti-/pro-apoptotic factors Bcl-2/caspase-9 expression and cellular ATP levels. We found that ginseng suppresses UCP-2, down-regulates caspase-9 while increasing ATP and insulin production/secretion and up-regulates Bcl-2, reducing apoptosis. These findings suggest that stimulation of insulin production and prevention of β cell loss by American ginseng extracts can occur via the inhibition of mitochondrial UCP-2, resulting in increase in the ATP level and the anti-apoptotic factor Bcl-2, while down-regulation of pro-apoptotic factor caspase-9 occurs, lowering the occurrence of apoptosis, which support the hypothesis.

  18. Physical adsorption and molecular dynamics

    International Nuclear Information System (INIS)

    Cohan, N.V.

    1981-01-01

    Some aspects of noble gases adsorption (except He) on graphite substracts are reviewed. Experimental results from this adsorption are analyzed and compared with molecular dynamics calculations. (L.C.) [pt

  19. Selective adsorption of bovine hemoglobin on functional TiO2 nano-adsorbents: surface physic-chemical properties determined adsorption activity

    Science.gov (United States)

    Guo, Shiguang; Zhang, Jianghua; Shao, Mingxue; Zhang, Xia; Liu, Yufeng; Xu, Junli; Meng, Hao; Han, Yide

    2015-04-01

    Surface functionalized nanoparticles are efficient adsorbents which have shown good potential for protein separation. In this work, we chose two different types of organic molecules, oleic acid (OA) and 3-glycidoxypropyltrimethoxy silane (GPTMS), to functionalize the surface of TiO2 nanoparticles, and we studied the effects of this modification on their surface physicochemical properties in correlation with their selective adsorption of proteins. The results showed that the surface zeta potential and the surface water wettability of the modified TiO2 were significantly changed in comparison with the original TiO2 nanoparticles. The adsorption activities of bovine hemoglobin (BHb) and bovine serum albumin (BSA) on these functionalized TiO2 samples were investigated under different conditions, including pH values, contact time, ion strength, and initial protein concentration. In comparison with the non-specific adsorption of original TiO2, however, both the OA-TiO2 and GPTMS-TiO2 exhibited increased BHb adsorption and decreased BSA adsorption at the same time. Using a binary protein mixture as the adsorption object, a higher separation factor (SF) was obtained for OA-TiO2 under optimum conditions. The different adsorption activities of BHb and BSA on the modified TiO2 were correlated with different interactions at the protein/solid interface, and the chemical force as well as the electrostatic force played an important role in the selective adsorption process.

  20. Partially hydrolyzed whey proteins prevent clinical symptoms in a cow's milk allergy mouse model and enhance regulatory T and B cell frequencies

    NARCIS (Netherlands)

    Kiewiet, Mensiena B. Gea; van Esch, Betty C. A. M.; Garssen, Johan; Faas, Marijke M.; de Vos, Paul

    2017-01-01

    Scope: Partially hydrolyzed cow's milk proteins are used to prevent cow's milk allergy in children. Here we studied the immunomodulatory mechanisms of partial cow's milk hydrolysates in vivo. Methods and results: Mice were sensitized with whey or partially hydrolyzed whey using cholera toxin.

  1. Partially hydrolyzed whey proteins prevent clinical symptoms in a cow's milk allergy mouse model and enhance regulatory T and B cell frequencies

    NARCIS (Netherlands)

    Kiewiet, Mensiena B. Gea; van Esch, Betty C. A. M.; Garssen, Johan; Faas, Marijke M.; de Vos, Paul

    Scope: Partially hydrolyzed cow's milk proteins are used to prevent cow's milk allergy in children. Here we studied the immunomodulatory mechanisms of partial cow's milk hydrolysates in vivo. Methods and results: Mice were sensitized with whey or partially hydrolyzed whey using cholera toxin.

  2. Partially hydrolyzed whey proteins prevent clinical symptoms in a cow's milk allergy mouse model and enhance regulatory T and B cell frequencies

    NARCIS (Netherlands)

    Kiewiet, Mensiena B Gea; van Esch, Betty C A M; Garssen, Johan; Faas, Marijke M; Vos, Paul

    2017-01-01

    SCOPE: Partially hydrolyzed cow's milk proteins are used to prevent cow's milk allergy in children. Here we studied the immunomodulatory mechanisms of partial cow's milk hydrolysates in vivo. METHODS AND RESULTS: Mice were sensitized with whey or partially hydrolyzed whey using cholera toxin.

  3. Sulfate adsorption on goethite

    Energy Technology Data Exchange (ETDEWEB)

    Rietra, R P.J.J.; Hiemstra, T; Riemsdijk, W.H. van

    1999-10-15

    Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichoimetry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used.

  4. Adsorption and Interfacial Electron Transfer of Saccharomyces Cerevisiae

    DEFF Research Database (Denmark)

    Hansen, Allan Glargaard; Boisen, Anja; Nielsen, Jens Ulrik

    2003-01-01

    We have studied the adsorption and electron-transfer dynamics of Saccharomyces cerevisiae (yeast) iso-l-cytochrome c adsorbed on Au(lll) electrodes in aqueous phosphate buffer media. This cytochrome possesses a thiol group dos e to the protein surface (Cysl02) suitable for linking the protein...

  5. High-protein diets prevent steatosis and induce hepatic accumulation of monomethyl branched-chain fatty acids

    NARCIS (Netherlands)

    Garcia Caraballo, Sonia C.; Comhair, Tine M.; Houten, Sander M.; Dejong, Cornelis H. C.; Lamers, Wouter H.; Koehler, S. Eleonore

    2014-01-01

    The hallmark of nonalcoholic fatty liver disease is steatosis of unknown etiology. To test how dietary protein decreases steatosis, we fed female C57BL/6 J mice low-fat (8 en%) or high-fat (42 en%) combined with low-protein (11 en%), high-protein (HP; 35 en%) or extra-high-protein (HPX; 58 en%)

  6. Alfalfa dwarf cytorhabdovirus P protein is a local and systemic RNA silencing supressor which inhibits programmed RISC activity and prevents transitive amplification of RNA silencing.

    Science.gov (United States)

    Bejerman, Nicolás; Mann, Krin S; Dietzgen, Ralf G

    2016-09-15

    Plants employ RNA silencing as an innate defense mechanism against viruses. As a counter-defense, plant viruses have evolved to express RNA silencing suppressor proteins (RSS), which target one or more steps of the silencing pathway. In this study, we show that the phosphoprotein (P) encoded by the negative-sense RNA virus alfalfa dwarf virus (ADV), a species of the genus Cytorhabdovirus, family Rhabdoviridae, is a suppressor of RNA silencing. ADV P has a relatively weak local RSS activity, and does not prevent siRNA accumulation. On the other hand, ADV P strongly suppresses systemic RNA silencing, but does not interfere with the short-distance spread of silencing, which is consistent with its lack of inhibition of siRNA accumulation. The mechanism of suppression appears to involve ADV P binding to RNA-induced silencing complex proteins AGO1 and AGO4 as shown in protein-protein interaction assays when ectopically expressed. In planta, we demonstrate that ADV P likely functions by inhibiting miRNA-guided AGO1 cleavage and prevents transitive amplification by repressing the production of secondary siRNAs. As recently described for lettuce necrotic yellows cytorhabdovirus P, but in contrast to other viral RSS known to disrupt AGO activity, ADV P sequence does not contain any recognizable GW/WG or F-box motifs, which suggests that cytorhabdovirus P proteins may use alternative motifs to bind to AGO proteins. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  7. Fundamentals of high pressure adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

    2009-12-15

    High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

  8. Traps for phosphorus adsorption

    International Nuclear Information System (INIS)

    Montoya, Nawer D; Villegas, Wilson E; Rodriguez, Lino M; Taborda, Nelson; Montes de C, Consuelo

    2001-01-01

    Several AL 2 O 3 supported oxides such as: NiO, CuO, Co 2 O 3 BaO, CeO 2 and ZnO were investigated for phosphorus adsorption. Zno/y-Al 2 O 3 exhibited the highest phosphorus adsorption capacity. However, since it diminishes the activity of to the reaction mixture it should be located upstream of the NoX catalyst, i.e. 0,3% Pd-H-MOR, in order to protect it against p poisoning. The treatment procedure with citric acid was effective for the removal of more than 70% phosphorus from the adsorbent, ZnO/y-Al 2 O 3

  9. Diffusion Influenced Adsorption Kinetics.

    Science.gov (United States)

    Miura, Toshiaki; Seki, Kazuhiko

    2015-08-27

    When the kinetics of adsorption is influenced by the diffusive flow of solutes, the solute concentration at the surface is influenced by the surface coverage of solutes, which is given by the Langmuir-Hinshelwood adsorption equation. The diffusion equation with the boundary condition given by the Langmuir-Hinshelwood adsorption equation leads to the nonlinear integro-differential equation for the surface coverage. In this paper, we solved the nonlinear integro-differential equation using the Grünwald-Letnikov formula developed to solve fractional kinetics. Guided by the numerical results, analytical expressions for the upper and lower bounds of the exact numerical results were obtained. The upper and lower bounds were close to the exact numerical results in the diffusion- and reaction-controlled limits, respectively. We examined the validity of the two simple analytical expressions obtained in the diffusion-controlled limit. The results were generalized to include the effect of dispersive diffusion. We also investigated the effect of molecular rearrangement of anisotropic molecules on surface coverage.

  10. Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films

    Science.gov (United States)

    Paribok, I. V.; Solomyanskii, A. E.; Zhavnerko, G. K.

    2016-02-01

    Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films are studied by means of microcontact printing, atomic force microscopy, and quartz crystal microbalance. It is shown that both the charge of polysaccharide macromolecules and the technique for deposition of their films onto the surface (via adsorption from a solution or covalent cross-linking) are factors that determine the degree of nonspecific adsorption of the protein on such films.

  11. Surface rheology of saponin adsorption layers.

    Science.gov (United States)

    Stanimirova, R; Marinova, K; Tcholakova, S; Denkov, N D; Stoyanov, S; Pelan, E

    2011-10-18

    min. Molecular interpretations of the observed trends are proposed when possible. Surprisingly, in the course of our study we found experimentally that the drop shape analysis method (DSA method) shows a systematically lower surface elasticity, in comparison with the other two methods used: Langmuir trough and capillary pressure tensiometry with spherical drops. The possible reasons for the observed discrepancy are discussed, and the final conclusion is that the DSA method has specific problems and may give incorrect results when applied to study the dynamic properties of systems with high surface elasticity, such as adsorption layers of saponins, lipids, fatty acids, solid particles, and some proteins. The last conclusion is particularly important because the DSA method recently became the preferred method for the characterization of fluid interfaces because of its convenience. © 2011 American Chemical Society

  12. Irreversible adsorption of particles on heterogeneous surfaces.

    Science.gov (United States)

    Adamczyk, Zbigniew; Jaszczółt, Katarzyna; Michna, Aneta; Siwek, Barbara; Szyk-Warszyńska, Lilianna; Zembala, Maria

    2005-12-30

    Methods of theoretical and experimental evaluation of irreversible adsorption of particles, e.g., colloids and globular proteins at heterogeneous surfaces were reviewed. The theoretical models were based on the generalized random sequential adsorption (RSA) approach. Within the scope of these models, localized adsorption of particles occurring as a result of short-ranged attractive interactions with discrete adsorption sites was analyzed. Monte-Carlo type simulations performed according to this model enabled one to determine the initial flux, adsorption kinetics, jamming coverage and the structure of the particle monolayer as a function of the site coverage and the particle/site size ratio, denoted by lambda. It was revealed that the initial flux increased significantly with the site coverage theta(s) and the lambda parameter. This behavior was quantitatively interpreted in terms of the scaled particle theory. It also was demonstrated that particle adsorption kinetics and the jamming coverage increased significantly, at fixed site coverage, when the lambda parameter increased. Practically, for alpha = lambda2theta(s) > 1 the jamming coverage at the heterogeneous surfaces attained the value pertinent to continuous surfaces. The results obtained prove unequivocally that spherically shaped sites were more efficient in binding particles in comparison with disk-shaped sites. It also was predicted that for particle size ratio lambda charge. Particle deposition occurred under diffusion-controlled transport conditions and their coverage was evaluated by direct particle counting using the optical and electron microscopy. Adsorption kinetics was quantitatively interpreted in terms of numerical solutions of the governing diffusion equation with the non-linear boundary condition derived from Monte-Carlo simulations. It was proven that for site coverage as low as a few percent the initial flux at heterogeneous surfaces attained the maximum value pertinent to homogeneous

  13. Surfaces of Microparticles in Colloids: Structure and Molecular Adsorption Kinetics

    Science.gov (United States)

    Dai, Hai-Lung

    2002-03-01

    Surfaces of micron and sub-micron size particles in liquid solution are probed by second harmonic generation (SHG) facilitated with femtosecond laser pulses. The particles probed include inorganic objects such as carbon black and color pigments, polymeric species like polystyrene beads, and biological systems such as blood cells and ecoli. In the experiments, dye molecules are first adsorbed onto the particle surface to allow generation of second harmonics upon light irradiation. Competition for adsorption between these surface dye molecules and the molecules of interest in the solution is then monitored by the SHG signal to reveal the molecular adsorption kinetics and surface structure. Specifically, surfactant adsorption on polymer surfaces, the structure of carbon black surface, and protein adsorption on biological surfaces, monitored by this technique, will be discussed.

  14. Dietary β-conglycinin prevents fatty liver induced by a high-fat diet by a decrease in peroxisome proliferator-activated receptor γ2 protein.

    Science.gov (United States)

    Yamazaki, Tomomi; Kishimoto, Kyoko; Miura, Shinji; Ezaki, Osamu

    2012-02-01

    Diets high in sucrose/fructose or fat can result in hepatic steatosis (fatty liver). Mice fed a high-fat diet, especially that of saturated-fat-rich oil, develop fatty liver with an increase in peroxisome proliferator-activated receptor (PPAR) γ2 protein in liver. The fatty liver induced by a high-fat diet is improved by knockdown of liver PPARγ2. In this study, we investigated whether β-conglycinin (a major protein of soy protein) could reduce PPARγ2 protein and prevent high-fat-diet-induced fatty liver in ddY mice. Mice were fed a high-starch diet (70 energy% [en%] starch) plus 20% (wt/wt) sucrose in their drinking water or a high-safflower-oil diet (60 en%) or a high-butter diet (60 en%) for 11 weeks, by which fatty liver is developed. As a control, mice were fed a high-starch diet with drinking water. Either β-conglycinin or casein (control) was given as dietary protein. β-Conglycinin supplementation completely prevented fatty liver induced by each type of diet, along with a reduction in adipose tissue weight. β-Conglycinin decreased sterol regulatory element-binding protein (SREBP)-1c and carbohydrate response element-binding protein (ChREBP) messenger RNAs (mRNAs) in sucrose-supplemented mice, whereas it decreased PPARγ2 mRNA (and its target genes CD36 and FSP27), but did not decrease SREBP-1c and ChREBP mRNAs, in mice fed a high-fat diet. β-Conglycinin decreased PPARγ2 protein and liver triglyceride (TG) concentration in a dose-dependent manner in mice fed a high-butter diet; a significant decrease in liver TG concentration was observed at a concentration of 15 en%. In conclusion, β-conglycinin effectively prevents fatty liver induced by a high-fat diet through a decrease in liver PPARγ2 protein. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Copper adsorption in tropical oxisols

    Directory of Open Access Journals (Sweden)

    Silveira Maria Lucia Azevedo

    2003-01-01

    Full Text Available Cu adsorption, at concentrations between 0 to 800 mg L-1, was evaluated in surface and subsurface samples of three Brazilian soils: a heavy clayey-textured Rhodic Hapludalf (RH, a heavy clayey-textured Anionic ''Rhodic'' Acrudox (RA and a medium-textured Anionic ''Xanthic'' Acrudox (XA. After adsorption, two consecutive extractions were performed to the samples which received 100 mg L-1 copper. Surface samples adsorbed higher amounts of Cu than the subsurface, and exhibited lower Cu removed after the extractions, reinforcing the influence of the organic matter in the reactions. Cu adsorption was significant in the subsurface horizons of the Oxisols, despite the positive balance of charge, demonstrating the existence of mechanisms for specific adsorption, mainly related to the predominance of iron and aluminum oxides in the mineral fractions. In these samples, Cu was easily removed from the adsorption sites. RH demonstrated a higher capacity for the Cu adsorption in both horizons.

  16. Adsorption kinetics of c-Fos and c-Jun to air-water interfaces.

    Science.gov (United States)

    Del Boca, Maximiliano; Nobre, Thatyane Morimoto; Zaniquelli, Maria Elisabete Darbello; Maggio, Bruno; Borioli, Graciela A

    2007-11-01

    The kinetics of adsorption to air-water interfaces of the biomembrane active transcription factors c-Fos, c-Jun and their mixtures is investigated. The adsorption process shows three distinct stages: a lag time, a fast pseudo zero-order stage, and a halting stage. The initial stage determines the course of the process, which is concentration dependent until the end of the fast stage. We show that c-Fos has faster adsorption kinetics than c-Jun over all three stages and that the interaction between both proteins is apparent in the adsorption profiles of the mixtures. Protein molecular reorganization at the interface determines the transition to the final adsorption stage of the pure proteins as well as that of the mixtures.

  17. Homeobox protein MSX-1 inhibits expression of bone morphogenetic protein 2, bone morphogenetic protein 4, and lymphoid enhancer-binding factor 1 via Wnt/β-catenin signaling to prevent differentiation of dental mesenchymal cells during the late bell stage.

    Science.gov (United States)

    Feng, Xiao-Yu; Wu, Xiao-Shan; Wang, Jin-Song; Zhang, Chun-Mei; Wang, Song-Lin

    2018-02-01

    Homeobox protein MSX-1 (hereafter referred to as MSX-1) is essential for early tooth-germ development. Tooth-germ development is arrested at bud stage in Msx1 knockout mice, which prompted us to study the functions of MSX-1 beyond this stage. Here, we investigated the roles of MSX-1 during late bell stage. Mesenchymal cells of the mandibular first molar were isolated from mice at embryonic day (E)17.5 and cultured in vitro. We determined the expression levels of β-catenin, bone morphogenetic protein 2 (Bmp2), Bmp4, and lymphoid enhancer-binding factor 1 (Lef1) after knockdown or overexpression of Msx1. Our findings suggest that knockdown of Msx1 promoted expression of Bmp2, Bmp4, and Lef1, resulting in elevated differentiation of odontoblasts, which was rescued by blocking the expression of these genes. In contrast, overexpression of Msx1 decreased the expression of Bmp2, Bmp4, and Lef1, leading to a reduction in odontoblast differentiation. The regulation of Bmp2, Bmp4, and Lef1 by Msx1 was mediated by the Wnt/β-catenin signaling pathway. Additionally, knockdown of Msx1 impaired cell proliferation and slowed S-phase progression, while overexpression of Msx1 also impaired cell proliferation and prolonged G1-phase progression. We therefore conclude that MSX-1 maintains cell proliferation by regulating transition of cells from G1-phase to S-phase and prevents odontoblast differentiation by inhibiting expression of Bmp2, Bmp4, and Lef1 at the late bell stage via the Wnt/β-catenin signaling pathway. © 2017 Eur J Oral Sci.

  18. Adsorption and collective paramagnetism

    CERN Document Server

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  19. Kinetics of the Adsorption of Bovine Serum Albumin of White Wine ...

    African Journals Online (AJOL)

    This study investigates the kinetics of adsorption of bovine serum albumin, BSA, in white wine model solutions onto activated carbon, AC, and alumina, AL. Pseudo-first order and pseudo-second order models were applied to determine the rate and mechanism of adsorption of the white wine protein during the haze removal ...

  20. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    OpenAIRE

    Chen, Qing; Tian, Yuanyuan; Li, Peng; Yan, Changhui; Pang, Yu; Zheng, Li; Deng, Hucheng; Zhou, Wen; Meng, Xianghao

    2017-01-01

    Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indi...

  1. Subcutaneous immunization with inactivated bacterial components and purified protein of Escherichia coli, Fusobacterium necrophorum and Trueperella pyogenes prevents puerperal metritis in Holstein dairy cows.

    Science.gov (United States)

    Machado, Vinícius Silva; Bicalho, Marcela Luccas de Souza; Meira Junior, Enoch Brandão de Souza; Rossi, Rodolfo; Ribeiro, Bruno Leonardo; Lima, Svetlana; Santos, Thiago; Kussler, Arieli; Foditsch, Carla; Ganda, Erika Korzune; Oikonomou, Georgios; Cheong, Soon Hon; Gilbert, Robert Owen; Bicalho, Rodrigo Carvalho

    2014-01-01

    In this study we evaluate the efficacy of five vaccine formulations containing different combinations of proteins (FimH; leukotoxin, LKT; and pyolysin, PLO) and/or inactivated whole cells (Escherichia coli, Fusobacterium necrophorum, and Trueperella pyogenes) in preventing postpartum uterine diseases. Inactivated whole cells were produced using two genetically distinct strains of each bacterial species (E. coli, F. necrophorum, and T. pyogenes). FimH and PLO subunits were produced using recombinant protein expression, and LKT was recovered from culturing a wild F. necrophorum strain. Three subcutaneous vaccines were formulated: Vaccine 1 was composed of inactivated bacterial whole cells and proteins; Vaccine 2 was composed of proteins only; and Vaccine 3 was composed of inactivated bacterial whole cells only. Two intravaginal vaccines were formulated: Vaccine 4 was composed of inactivated bacterial whole cells and proteins; and Vaccine 5 was composed of PLO and LKT. To evaluate vaccine efficacy, a randomized clinical trial was conducted at a commercial dairy farm; 371 spring heifers were allocated randomly into one of six different treatments groups: control, Vaccine 1, Vaccine 2, Vaccine 3, Vaccine 4 and Vaccine 5. Late pregnant heifers assigned to one of the vaccine groups were each vaccinated twice: at 230 and 260 days of pregnancy. When vaccines were evaluated grouped as subcutaneous and intravaginal, the subcutaneous ones were found to significantly reduce the incidence of puerperal metritis. Additionally, subcutaneous vaccination significantly reduced rectal temperature at 6±1 days in milk. Reproduction was improved for cows that received subcutaneous vaccines. In general, vaccination induced a significant increase in serum IgG titers against all antigens, with subcutaneous vaccination again being more effective. In conclusion, subcutaneous vaccination with inactivated bacterial components and/or protein subunits of E. coli, F. necrophorum and T. pyogenes

  2. Adsorption of IgG onto hydrophobic teflon. Differences between the F(ab) and F(c) domains

    NARCIS (Netherlands)

    Vermeer, AWP; Giacomelli, CE; Norde, W

    2001-01-01

    The effect of differences in the degree of hydrophobicity of protein patches/fragments on the adsorption behaviour of the protein is investigated. The adsorption isotherm of a monoclonal mouse anti-human immunoglobulin G (isotype 2b) onto hydrophobic Teflon particles is measured using a depletion

  3. Interaction between calcium and phosphate adsorption on goethite.

    Science.gov (United States)

    Rietra, R P; Hiemstra, T; van Riemsdijk, W H

    2001-08-15

    Quantitatively, little is known about the ion interaction processes that are responsible for the binding of phosphate in soil, water, and sediment, which determine the bioavailability and mobility of phosphate. Studies have shown that metal hydroxides are often responsible for the binding of PO4 in soils and sediments, but the binding behavior of PO4 in these systems often differs significantly from adsorption studies on metal hydroxides in laboratory. The interaction between PO4 and Ca adsorption was studied on goethite because Ca can influence the PO4 adsorption equilibria. Since adsorption interactions are very difficult to discriminate from precipitation reactions, conditions were chosen to prevent precipitation of Ca-PO4 solids. Adsorption experiments of PO4 and Ca, individually and in combination, show a strong interaction between adsorbed Ca and PO4 on goethite for conditions below the saturation index of apatite. It is shown that it is possible to predict the adsorption and interaction of PO4 and Ca on electrostatic arguments using the model parameter values derived from the single-ion systems and without invoking ternary complex formation or precipitation. The model enables the prediction of the Ca-PO4 interaction for environmentally relevant calcium and phosphate concentrations.

  4. New developments for localized adsorption

    International Nuclear Information System (INIS)

    Boudh-hir, M.E.

    1989-02-01

    Using the diagrammatic expansion, new developments for localized adsorption are found. It is proved that the correlations in the system, in the absence of the attractive site potential, and the periodicity of the sites play a fundamental role in the adsorption phenomena. 14 refs, 2 figs, 2 tabs

  5. Arsenite adsorption on goethite at elevated temperatures

    International Nuclear Information System (INIS)

    Kersten, Michael; Vlasova, Nataliya

    2009-01-01

    Experimental closed-system ΔT acid-base titrations between 10 deg. C and 75 deg. C were used to constrain a temperature-dependent 1-pK basic Stern model of the goethite surface complexation reactions. Experimental data for the temperature dependence of pH PZC determined by the one-term Van't Hoff extrapolation yield a value for goethite surface protonation enthalpy of -49.6 kJ mol -1 in good agreement with literature data. Batch titration data between 10 deg. C and 75 deg. C with arsenite concentrations between 10 μM and 100 μM yield adsorption curves, which increases with pH, peak at a pH of 9, and decrease at higher pH values. The slope of this bend becomes steeper with increasing temperature. A 1-pK charge distribution model in combination with a basic Stern layer option could be established for the pH-dependent arsenite adsorption. Formation of two inner-sphere bidentate surface complexes best matched the experimental data in agreement with published EXAFS spectroscopic information. The temperature behaviour of the thus derived intrinsic equilibrium constants can be well represented by the linear Van't Hoff logK T int vs. 1/T plot. Adsorption of arsenite on the goethite surface is exothermic (negative Δ r H 298 values) and therefore becomes weaker with increasing temperature. Application of the new constants with the aqueous speciation code VMINTEQ predicts that the As(III) concentration in presence of goethite sorbent decreases by 10 times once the hydrothermal solution is cooled from 99 deg. C to 1 deg. C. The model curve matches data from a natural thermal water spring system. The increase of adsorption efficiency for As along the temperature gradient may well serve as an additional process to prevent ecosystem contamination by As-rich water seepage from geothermal energy generation facilities

  6. Targeting Sentinel Proteins and Extrasynaptic Glutamate Receptors: a Therapeutic Strategy for Preventing the Effects Elicited by Perinatal Asphyxia?

    Science.gov (United States)

    Herrera-Marschitz, Mario; Perez-Lobos, Ronald; Lespay-Rebolledo, Carolyne; Tapia-Bustos, Andrea; Casanova-Ortiz, Emmanuel; Morales, Paola; Valdes, Jose-Luis; Bustamante, Diego; Cassels, Bruce K

    2018-02-01

    Perinatal asphyxia (PA) is a relevant cause of death at the time of labour, and when survival is stabilised, associated with short- and long-term developmental disabilities, requiring inordinate care by health systems and families. Its prevalence is high (1 to 10/1000 live births) worldwide. At present, there are few therapeutic options, apart from hypothermia, that regrettably provides only limited protection if applied shortly after the insult.PA implies a primary and a secondary insult. The primary insult relates to the lack of oxygen, and the secondary one to the oxidative stress triggered by re-oxygenation, formation of reactive oxygen (ROS) and reactive nitrogen (RNS) species, and overactivation of glutamate receptors and mitochondrial deficiencies. PA induces overactivation of a number of sentinel proteins, including hypoxia-induced factor-1α (HIF-1α) and the genome-protecting poly(ADP-ribose) polymerase-1 (PARP-1). Upon activation, PARP-1 consumes high amounts of ATP at a time when this metabolite is scarce, worsening in turn the energy crisis elicited by asphyxia. The energy crisis also impairs ATP-dependent transport, including glutamate re-uptake by astroglia. Nicotinamide, a PARP-1 inhibitor, protects against the metabolic cascade elicited by the primary stage, avoiding NAD + exhaustion and the energetic crisis. Upon re-oxygenation, however, oxidative stress leads to nuclear translocation of the NF-κB subunit p65, overexpression of the pro-inflammatory cytokines IL-1β and TNF-α, and glutamate-excitotoxicity, due to impairment of glial-glutamate transport, extracellular glutamate overflow, and overactivation of NMDA receptors, mainly of the extrasynaptic type. This leads to calcium influx, mitochondrial impairment, and inactivation of antioxidant enzymes, increasing further the activity of pro-oxidant enzymes, thereby making the surviving neonate vulnerable to recurrent metabolic insults whenever oxidative stress is involved. Here, we discuss

  7. Taurine: A Potential Ergogenic Aid for Preventing Muscle Damage and Protein Catabolism and Decreasing Oxidative Stress Produced by Endurance Exercise

    Directory of Open Access Journals (Sweden)

    Flávia G. De Carvalho

    2017-09-01

    Full Text Available The aim of this study was to evaluate the effects of taurine and chocolate milk supplementation on oxidative stress and protein metabolism markers, and aerobic parameters in triathletes.Methods: A double-blind, crossover study was conducted with 10 male triathletes, aged 30.9 ± 1.3 year, height 1.79 ± 0.01 m and body weight 77.45 ± 2.4 kg. Three grams of taurine and 400 ml of chocolate milk (TAUchoc, or a placebo (chocolate milk (CHOC was ingested post exercise for 8 weeks. Oxidative stress marker levels, and 24 h urinary nitrogen, creatinine, and urea excretion were measured before and after 8 weeks of training and supplementation with TAUchoc or CHOC. A maximal incremental running test on a treadmill was performed in order to evaluate aerobic parameters: Vmax, heart rate (HR and rate of perceived exertion (RPE.Results: TAUchoc treatment during the 8 weeks resulted in increased taurine plasma levels (PRE 201.32 ± 29.03 μmol/L and POST 234.36 ± 35.51 μmol/L, p = 0.01, decreased malondialdehyde levels (19.4%, p = 0.03 and urinary nitrogen excretion (−33%, p = 0.03, and promoted positive nitrogen balance (p = 0.01. There were no changes in reduced glutathione (TAUchoc PRE 0.72 ± 0.08 mmol/L and POST 0.83 ± 0.08 mmol/L; CHOC PRE 0.69 ± 0.08 mmol/L and POST 0.81 ± 0.06 mmol/L, vitamin E plasma levels (TAUchoc PRE 33.99 ± 2.52 μmol/L and 35.95 ± 2.80 μmol/L and CHOC PRE 31.48 ± 2.12 μmol/L and POST 33.77 ± 3.64 μmol/L, or aerobic parameters, which were obtained in the last phase of the maximal incremental running test (Vmax TAUchoc PRE 13 ± 1.4 km/h and POST 13.22 ± 1.34 km/h; CHOC PRE 13.11 ± 2.34 km/h and POST 13.11 ± 2.72 km/h, the heart rate values were TAUchoc PRE 181.89 ± 24.18 bpm and POST 168.89 ± 46.56 bpm; CHOC PRE 181.56 ± 2.14 bpm and POST 179.78 ± 3.4 bpm, and the RPE were TAUchoc PRE 8.33 ± 2.4 AU and POST 9.1 ± 2.1 AU; CHOC PRE 8.11 ± 4.94 AU and POST 8.78 ± 2.78 AU.Conclusion: Taurine supplementation

  8. A supramolecular strategy for self-mobile adsorption sites in affinity membrane.

    Science.gov (United States)

    Lin, Ligang; Dong, Meimei; Liu, Chunyu; Wei, Chenjie; Wang, Yuanyuan; Sun, Hui; Ye, Hui

    2014-09-01

    Disclosed here is the design of a novel supramolecular membrane with self-mobile adsorption sites for biomolecules purification. In the 3D micropore channels of membrane matrix, the ligands are conjugated onto the cyclic compounds in polyrotaxanes for protein adsorption. During membrane filtration, the adsorption sites can rotate and/or slide along the axial chain, which results in the enhanced adsorption capacity. The excellent performance of supra-molecular membrane is related with the dynamic working manner of adsorption sites, which plays a crucial role on avoiding spatial mismatching and short-circuit effect. The supra-molecular strategy described here has general suggestions for the "sites" involved technologies such as catalysis, adsorption, and sensors, which is of broad interest. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Molecular simulation of fibronectin adsorption onto polyurethane surfaces

    Science.gov (United States)

    Polyethylene glycol-based polyurethanes have been widely used in biomedical applications, however are prone to swelling. A natural polyol, castor oil can be incorporated into these polyurethanes to control the degree of the swelling, which alters mechanical properties and protein adsorption characte...

  10. The Adsorption of Dextranase onto Mg/Fe-Layered Double Hydroxide: Insight into the Immobilization

    Directory of Open Access Journals (Sweden)

    Yi Ding

    2018-03-01

    Full Text Available We report the adsorption of dextranase on a Mg/Fe-layered double hydroxide (Mg/Fe-LDH. We focused the effects of different buffers, pH, and amino acids. The Mg/Fe-LDH was synthesized, and adsorption experiments were performed to investigate the effects. The maximum adsorption occurred in pH 7.0 4-(2-hydroxyethyl-1-piperazineethanesulfonic acid (HEPES buffer, and the maximum dextranase adsorption uptake was 1.38 mg/g (416.67 U/mg; histidine and phenylalanine could affect the adsorption. A histidine tag could be added to the protein to increase the adsorption significantly. The performance features and mechanism were investigated with X-ray diffraction patterns (XRD and Fourier transform infrared spectra (FTIR. The protein could affect the crystal structure of LDH, and the enzyme was adsorbed on the LDH surface. The main interactions between the protein and LDH were electrostatic and hydrophobic. Histidine and phenylalanine could significantly affect the adsorption. The hexagonal morphology of LDH was not affected after adsorption.

  11. Organoselenium compounds prevent hyperphosphorylation of cytoskeletal proteins induced by the neurotoxic agent diphenyl ditelluride in cerebral cortex of young rats

    International Nuclear Information System (INIS)

    Moretto, M.B.; Funchal, C.; Zeni, G.; Rocha, J.B.T.; Pessoa-Pureur, R.

    2005-01-01

    In this work we investigated the protective ability of the selenium compounds ebselen and diphenyl diselenide against the effect of diphenyl ditelluride on the in vitro incorporation of 32 P into intermediate filament (IF) proteins from slices of cerebral cortex of 17-day-old rats. We observed that ditelluride in the concentrations of 1, 15 and 50 μM induced hyperphosphorylation of the high-salt Triton insoluble neurofilament subunits (NF-M and NF-L), glial fibrillary acidic protein (GFAP) and vimentin, without altering the immunocontent of these proteins. Concerning the selenium compounds, diselenide (1, 15 and 50 μM) did not induce alteration of the in vitro phosphorylation of the IF proteins. Otherwise, ebselen induced an altered in vitro phosphorylation of the cytoskeletal proteins in a dose-dependent manner. At intermediate concentrations (15 and 30 μM) it increased the in vitro phosphorylation even though, at low (5 μM) or high (50 and 100 μM) concentrations this compound was ineffective in altering the activity of the cytoskeletal-associated phosphorylating system. In addition, 15 μM diselenide and 5 μM ebselen, presented a protective effect against the action of ditelluride, on the phosphorylation of the proteins studied. Considering that hyperphosphorylation of cytoskeletal proteins is associated with neuronal dysfunction and neurodegeneration, it is probable that the effects of ditelluride could be related to the remarkable neurotoxicity of this organic form of tellurium. Furthermore the neuroprotective action of selenium compounds against tellurium effects could be a promising route to be exploited for a possible treatment of organic tellurium poisoning

  12. The putative Agrobacterium transcriptional activator-like virulence protein VirD5 may target T-complex to prevent the degradation of coat proteins in the plant cell nucleus.

    Science.gov (United States)

    Wang, Yafei; Peng, Wei; Zhou, Xu; Huang, Fei; Shao, Lingyun; Luo, Meizhong

    2014-09-01

    Agrobacterium exports at least five virulence proteins (VirE2, VirE3, VirF, VirD2, VirD5) into host cells and hijacks some host plant factors to facilitate its transformation process. Random DNA binding selection assays (RDSAs), electrophoretic mobility shift assays (EMSAs) and yeast one-hybrid systems were used to identify protein-bound DNA elements. Bimolecular fluorescence complementation, glutathione S-transferase pull-down and yeast two-hybrid assays were used to detect protein interactions. Protoplast transformation, coprecipitation, competitive binding and cell-free degradation assays were used to analyze the relationships among proteins. We found that Agrobacterium VirD5 exhibits transcriptional activation activity in yeast, is located in the plant cell nucleus, and forms homodimers. A specific VirD5-bound DNA element designated D5RE (VirD5 response element) was identified. VirD5 interacted directly with Arabidopsis VirE2 Interacting Protein 1 (AtVIP1). However, the ternary complex of VirD5-AtVIP1-VirE2 could be detected, whereas that of VirD5-AtVIP1-VBF (AtVIP1 Binding F-box protein) could not. We demonstrated that VirD5 competes with VBF for binding to AtVIP1 and stabilizes AtVIP1 and VirE2 in the cell-free degradation system. Our results indicated that VirD5 may act as both a transcriptional activator-like effector to regulate host gene expression and a protector preventing the coat proteins of the T-complex from being quickly degraded by the host's ubiquitin proteasome system (UPS). © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  13. Preventive Effects of Resveratrol on Endocannabinoid System and Synaptic Protein Modifications in Rat Cerebral Cortex Challenged by Bilateral Common Carotid Artery Occlusion and Reperfusion

    Directory of Open Access Journals (Sweden)

    Gianfranca Carta

    2018-01-01

    Full Text Available This study aims to evaluate the putative roles of a single acute dose of resveratrol (RVT in preventing cerebral oxidative stress induced by bilateral common carotid artery occlusion, followed by reperfusion (BCCAO/R and to investigate RVT’s ability to preserve the neuronal structural integrity. Frontal and temporal-occipital cortices were examined in two groups of adult Wistar rats, sham-operated and submitted to BCCAO/R. In both groups, 6 h before surgery, half the rats were gavage-fed with a single dose of RVT (40 mg/per rat in 300 µL of sunflower oil as the vehicle, while the second half received the vehicle alone. In the frontal cortex, RVT pre-treatment prevented the BCCAO/R-induced increase of lipoperoxides, augmented concentrations of palmitoylethanolamide and docosahexaenoic acid, increased relative levels of the cannabinoid receptors type 1 (CB1 and 2 (CB2, and peroxisome-proliferator-activated-receptor (PPAR-α proteins. Increased expression of CB1/CB2 receptors mirrored that of synaptophysin and post-synaptic density-95 protein. No BCCAO/R-induced changes occurred in the temporal-occipital cortex. Collectively, our results demonstrate that, in the frontal cortex, RVT pre-treatment prevents the BCCAO/R-induced oxidative stress and modulates the endocannabinoid and PPAR-α systems. The increased expression of synaptic structural proteins further suggests the possible efficacy of RVT as a dietary supplement to preserve the nervous tissue metabolism and control the physiological response to the hypoperfusion/reperfusion challenge.

  14. Adsorption Desalination: A Novel Method

    KAUST Repository

    Ng, Kim Choon

    2010-11-15

    The search for potable water for quenching global thirst remains a pressing concern throughout many regions of the world. The demand for new and sustainable sources and the associated technologies for producing fresh water are intrinsically linked to the solving of potable water availability and hitherto, innovative and energy efficient desalination methods seems to be the practical solutions. Quenching global thirst by adsorption desalination is a practical and inexpensive method of desalinating the saline and brackish water to produce fresh water for agriculture irrigation, industrial, and building applications. This chapter provides a general overview of the adsorption fundamentals in terms of adsorption isotherms, kinetics, and heat of adsorption. It is then being more focused on the principles of thermally driven adsorption desalination methods. The recent developments of adsorption desalination plants and the effect of operating conditions on the system performance in terms of specific daily water production and performance ratio are presented. Design of a large commercial adsorption desalination plant is also discussed herein.

  15. Deviation of the typical AAA substrate-threading pore prevents fatal protein degradation in yeast Cdc48.

    Science.gov (United States)

    Esaki, Masatoshi; Islam, Md Tanvir; Tani, Naoki; Ogura, Teru

    2017-07-14

    Yeast Cdc48 is a well-conserved, essential chaperone of ATPases associated with diverse cellular activity (AAA) proteins, which recognizes substrate proteins and modulates their conformations to carry out many cellular processes. However, the fundamental mechanisms underlying the diverse pivotal roles of Cdc48 remain unknown. Almost all AAA proteins form a ring-shaped structure with a conserved aromatic amino acid residue that is essential for proper function. The threading mechanism hypothesis suggests that this residue guides the intrusion of substrate proteins into a narrow pore of the AAA ring, thereby becoming unfolded. By contrast, the aromatic residue in one of the two AAA rings of Cdc48 has been eliminated through evolution. Here, we show that artificial retrieval of this aromatic residue in Cdc48 is lethal, and essential features to support the threading mechanism are required to exhibit the lethal phenotype. In particular, genetic and biochemical analyses of the Cdc48 lethal mutant strongly suggested that when in complex with the 20S proteasome, essential proteins are abnormally forced to thread through the Cdc48 pore to become degraded, which was not detected in wild-type Cdc48. Thus, the widely applicable threading model is less effective for wild-type Cdc48; rather, Cdc48 might function predominantly through an as-yet-undetermined mechanism.

  16. Maintenance of energy expenditure on high-protein vs. high-carbohydrate diets at a constant body weight may prevent a positive energy balance.

    Science.gov (United States)

    Martens, E A; Gonnissen, H K; Gatta-Cherifi, B; Janssens, P L; Westerterp-Plantenga, M S

    2015-10-01

    Relatively high-protein diets are effective for body weight loss, and subsequent weight maintenance, yet it remains to be shown whether these diets would prevent a positive energy balance. Therefore, high-protein diet studies at a constant body weight are necessary. The objective was to determine fullness, energy expenditure, and macronutrient balances on a high-protein low-carbohydrate (HPLC) diet compared with a high-carbohydrate low-protein (HCLP) diet at a constant body weight, and to assess whether effects are transient or sustained after 12 weeks. A randomized parallel study was performed in 14 men and 18 women [mean ± SD age: 24 ± 5 y; BMI (in kg/m(2)): 22.8 ± 2.0] on diets containing 30/35/35 (HPLC) or 5/60/35 (HCLP) % of energy from protein/carbohydrate/fat. Significant interactions between dietary intervention and time on total energy expenditure (TEE) (P = 0.013), sleeping metabolic rate (SMR) (P = 0.040), and diet-induced thermogenesis (DIT) (P = 0.027) appeared from baseline to wk 12. TEE was maintained in the HPLC diet group, while it significantly decreased throughout the intervention period in the HCLP diet group (wk 1: P = 0.002; wk 12: P = 0.001). Energy balance was maintained in the HPLC diet group, and became positive in the HCLP diet group at wk 12 (P = 0.008). Protein balance varied directly according to the amount of protein in the diet, and diverged significantly between the diets (P = 0.001). Fullness ratings were significantly higher in the HPLC vs. the HCLP diet group at wk 1 (P = 0.034), but not at wk 12. Maintenance of energy expenditure on HPLC vs. HCLP diets at a constant body weight may prevent development of a positive energy balance, despite transiently higher fullness. The study was registered on clinicaltrials.gov with Identifier: NCT01551238. Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  17. Neutrophil proteomic analysis reveals the participation of antioxidant enzymes, motility and ribosomal proteins in the prevention of ischemic effects by preconditioning

    DEFF Research Database (Denmark)

    Arshid, S; Tahir, M; Fontes, B

    2017-01-01

    therapeutic application; however the exact underlying mechanism is not clear. Neutrophils play an important role in the mechanism of injuries caused by ischemia and reperfusion while IPC led to a decrease in neutrophil stimulation and activation. The effect of preconditioning on the neutrophil proteome...... in such conditions, there is no report of a proteomic study providing a broader view of this scenario. Here we describe a group of proteins significantly regulated by ischemia and reperfusion being such regulation prevented by preconditioning. Such finding may provide relevant information for a deeper understanding...

  18. Efficient protein-repelling thin films regulated by chain mobility of low-Tg polymers with increased stability via crosslinking

    Science.gov (United States)

    Zhang, Jinghui; Huang, Zhiwei; Liu, Dan

    2017-12-01

    Polymer thin films are generally employed as coatings on implants to prevent protein adsorption. Polymer chain mobility and surface softness have been found to contribute to the protein resistance, but also bring film instability in a liquid protein medium. We investigated the protein resistance ability of three low-Tg polymers, including hydrophobic polymers polyisoprene (PI), poly(n-butyl methacrylate) (PnBMA) and hydrophilic polyethylene oxide (PEO), by overcoming the instability issue with crosslinking. We found that the Tgs of PI and PEO can be increased to around 0 °C after crosslinking. The remained strong chain mobility of both films can still resist protein adsorption regardless the hydrophobicity, yet greatly increases the film stability under an aqueous circumstance. The PnBMA film increased its Tg to around room temperature after crosslinking, which deteriorated the protein-resistance ability having the surface covered by BSA molecules. Our results support that the chain mobility of a polymer film plays an important role in resisting protein adsorption due to the increased entropy associated with more mobile polymer chains. By tune the degree of crosslinking, the stability of polymer in aqueous environment can be increased while the protein resistant ability can be remained. Our results provide a new strategy to design polymer materials for effective antifouling.

  19. Protein engineering of the chemokine CCL20 prevents psoriasiform dermatitis in an IL-23-dependent murine model

    DEFF Research Database (Denmark)

    Getschman, A E; Imai, Y; Larsen, O

    2017-01-01

    signaling. When given in an IL-23-dependent mouse model for psoriasis, CCL20 S64C prevented psoriatic inflammation and the up-regulation of IL-17A and IL-22. Our results validate CCR6 as a tractable therapeutic target for psoriasis and demonstrate the value of CCL20 S64C as a lead compound....

  20. Adsorption facility and adsorption vessel for radioactive carbon dioxide

    International Nuclear Information System (INIS)

    Harashina, Heihachi; Miwa, Keiichi; Kobayashi, Takeo.

    1992-01-01

    If 14 CO 2 gas-containing gases to be adsorbed are pressurized and sent to a packaging adsorption means, CO 2 ingredient in the gases to be adsorbed is adsorbed or absorbed, and remaining gases are passed through and sent out to downstream. CO 2 adsorption or absorption of the packaging adsorption means is judged by monitoring the state of the remaining gases, and if it is normal, remaining gases are sent further to downstream and processed. If abnormality is found, a gas feedback system is operated, and CO 2 removing gas is sent again to the packaging adsorption means, in which CO 2 gases are adsorbed or absorbed again repeatingly. With such procedures, in a case where C 14 nuclides having a long half decay time are supplied in the form of 14 CO 2 gas, they are efficiently adsorbed or absorbed in the packaging system to improve removing and storing property of 14 C nuclides. (T.M.)

  1. Carbon nanomaterials for gas adsorption

    CERN Document Server

    Terranova, Maria Letizia

    2012-01-01

    Research in adsorption of gases by carbon nanomaterials has experienced considerable growth in recent years, with increasing interest for practical applications. Many research groups are now producing or using such materials for gas adsorption, storage, purification, and sensing. This book provides a selected overview of some of the most interesting scientific results regarding the outstanding properties of carbon nanomaterials for gas adsorption and of interest both for basic research and technological applications. Topics receiving special attention in this book include storage of H, purific

  2. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  3. Development of Spore Protein of Myxobolus koi as an Immunostimulant for Prevent of Myxobolusis on Gold Fish (Cyprinus carpio Linn) by Oral Immunisation

    Science.gov (United States)

    Mahasri, Gunanti

    2017-02-01

    Production of Gold fish (Cyprinus carpio Linn) in Indonesia has always increased from 2013 to 2015 year by year with increasing average 2% per year. The amount of production was respectively 571.892 tonnes, 1129.273 tonnes, and 1186.674 tonnes. There were almost no problems to sale of gold fish because it had a good enough prospect. The aims of this research were Isolation of spore protein of Myxobolus koi by using SDS-PAGE to analyze immun respons and survival rate gold fish that immunized with spore protein of Myxobolus koi. The method of this research used experimental method, and belonged to 4 treatments that are: Controle = the group of gold fish not immunized with protein spore of Myxobolus koi neither infected by Myxobolus koi (T1). The group immunized and infested by spore of Myxobolus koi (T2), The group which immunized and not infested by Myxobolus koi (T3), and The group only infested by Myxobolus koi (T4). The dose of immunostimulant was 5 ml in 1 kg of food. The result showed that there were two bands of whole spore protein with molecule weight (MW) 150 kDa and 72 kDa and one band of crude protein Myxobolus koi with molecule weight 73 kD and the optical density point was 0.132 on the first day and increased to 0.769 on the 56 th day. The result also showed that the immun respons and survival rate increased from 27% to 86% in chellence test. The protein spore of Myxobolus koi can used to develops material for immunostimulant and to prevent the myxobolusis.

  4. Increased protein damage in renal glomeruli, retina, nerve, plasma and urine and its prevention by thiamine and benfotiamine therapy in a rat model of diabetes.

    Science.gov (United States)

    Karachalias, N; Babaei-Jadidi, R; Rabbani, N; Thornalley, P J

    2010-07-01

    The aim of this study was to quantify protein damage by glycation, oxidation and nitration in a rat model of diabetes at the sites of development of microvascular complications, including the effects of thiamine and benfotiamine therapy. Diabetes was induced in male Sprague-Dawley rats by 55 mg/kg streptozotocin and moderated by insulin (2 U twice daily). Diabetic and control rats were given thiamine or benfotiamine (7 or 70 mg kg(-1) day(-1)) over 24 weeks. Plasma, urine and tissues were collected and analysed for protein damage by stable isotopic dilution analysis MS. There were two- to fourfold increases in fructosyl-lysine and AGE content of glomerular, retinal, sciatic nerve and plasma protein in diabetes. Increases in AGEs were reversed by thiamine and benfotiamine therapy but increases in fructosyl-lysine were not. Methionine sulfoxide content of plasma protein and 3-nitrotyrosine content of sciatic nerve protein were increased in diabetes. Plasma glycation free adducts were increased up to twofold in diabetes; the increases were reversed by thiamine. Urinary excretion of glycation, oxidation and nitration free adducts was increased by seven- to 27-fold in diabetes. These increases were reversed by thiamine and benfotiamine therapy. AGEs, particularly arginine-derived hydroimidazolones, accumulate at sites of microvascular complication development and have markedly increased urinary excretion rates in experimental diabetes. Thiamine and benfotiamine supplementation prevented tissue accumulation and increased urinary excretion of protein glycation, oxidation and nitration adducts. Similar effects may contribute to the reversal of early-stage clinical diabetic nephropathy by thiamine.

  5. Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism.

    Science.gov (United States)

    Ikizler, T Alp; Cano, Noel J; Franch, Harold; Fouque, Denis; Himmelfarb, Jonathan; Kalantar-Zadeh, Kamyar; Kuhlmann, Martin K; Stenvinkel, Peter; TerWee, Pieter; Teta, Daniel; Wang, Angela Yee-Moon; Wanner, Christoph

    2013-12-01

    Protein energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with adverse clinical outcomes, especially in individuals receiving maintenance dialysis therapy. A multitude of factors can affect the nutritional and metabolic status of CKD patients requiring a combination of therapeutic maneuvers to prevent or reverse protein and energy depletion. These include optimizing dietary nutrient intake, appropriate treatment of metabolic disturbances such as metabolic acidosis, systemic inflammation, and hormonal deficiencies, and prescribing optimized dialytic regimens. In patients where oral dietary intake from regular meals cannot maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is shown to be effective in replenishing protein and energy stores. In clinical practice, the advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic strategies such as anabolic steroids, growth hormone, and exercise, in combination with nutritional supplementation or alone, have been shown to improve protein stores and represent potential additional approaches for the treatment of PEW. Appetite stimulants, anti-inflammatory interventions, and newer anabolic agents are emerging as novel therapies. While numerous epidemiological data suggest that an improvement in biomarkers of nutritional status is associated with improved survival, there are no large randomized clinical trials that have tested the effectiveness of nutritional interventions on mortality and morbidity.

  6. Strong Selective Adsorption of Polymers.

    Science.gov (United States)

    Ge, Ting; Rubinstein, Michael

    2015-06-09

    A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By "selective" we mean specific attraction between a subset of all monomers, called "sticky", and a subset of surface sites, called "adsorption sites". We demonstrate that, in addition to the expected dependence on the polymer volume fraction ϕ bulk in the bulk solution, selective adsorption strongly depends on the ratio between two characteristic length scales, the root-mean-square distance l between neighboring sticky monomers along the polymer, and the average distance d between neighboring surface adsorption sites. The role of the ratio l / d arises from the fact that a polymer needs to deform to enable the spatial commensurability between its sticky monomers and the surface adsorption sites for selective adsorption. We study strong selective adsorption of both telechelic polymers with two end monomers being sticky and multisticker polymers with many sticky monomers between sticky ends. For telechelic polymers, we identify four adsorption regimes at l / d 1, we expect that the adsorption layer at exponentially low ϕ bulk consists of separated unstretched loops, while as ϕ bulk increases the layer crosses over to a brush of extended loops with a second layer of weakly overlapping tails. For multisticker chains, in the limit of exponentially low ϕ bulk , adsorbed polymers are well separated from each other. As l / d increases, the conformation of an individual polymer changes from a single-end-adsorbed "mushroom" to a random walk of loops. For high ϕ bulk , adsorbed polymers at small l / d are mushrooms that cover all the adsorption sites. At sufficiently large l / d , adsorbed multisticker polymers strongly overlap. We anticipate the formation of a self-similar carpet and with increasing l / d a two-layer structure with a brush of loops covered by a self-similar carpet. As l / d exceeds the

  7. Water adsorption on goethite: Application of multilayer adsorption models

    Science.gov (United States)

    Hatch, C. D.; Tumminello, R.; Meredith, R.

    2016-12-01

    Adsorbed water on the surface of atmospheric mineral dust has recently been shown to significantly affect the ability of mineral dust aerosol to act as cloud condensation nuclei. We have studied water adsorption as a function of relative humidity (RH) on goethite (α-FeO(OH)), a common component of atmospheric mineral dust. The goethite surface area and particle size was determined using BET analysis and with N2 as an adsorbate and scanning electron microscopy, respectively. Water adsorption on the sample was monitored using horizontal attenuated total reflectance Fourier transform infrared (HATR-FTIR) spectroscopy equipped with a flow cell. Water content was determined using Beer's law and the optical constants for bulk water. The results were analyzed using Type II adsorption isotherms to model multilayer adsorption, including BET (Brunauer, Emmet and Teller), FHH (Frenkel, Halsey and Hill) and Freundlich. BET fits to experimental data provide parameters of monolayer coverage, while the FHH and Freundlich isotherms provide insights into multilayer adsorption mechanisms. Results indicate that goethite contains 5% H2O by mass at 50% RH, which increases to 12% by mass at 90% RH. Adsorption parameters and experimental results will be presented.

  8. The Sur7 protein regulates plasma membrane organization and prevents intracellular cell wall growth in Candida albicans.

    Science.gov (United States)

    Alvarez, Francisco J; Douglas, Lois M; Rosebrock, Adam; Konopka, James B

    2008-12-01

    The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S. cerevisiae. The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. cerevisiae, a C. albicans sur7Delta mutant displayed defects in endocytosis and morphogenesis. Septins and actin were mislocalized, and cell wall synthesis was very abnormal, including long projections of cell wall into the cytoplasm. Several phenotypes of the sur7Delta mutant are similar to the effects of inhibiting beta-glucan synthase, suggesting that the abnormal cell wall synthesis is related to activation of chitin synthase activity seen under stress conditions. These results expand the roles of eisosomes by demonstrating that Sur7 is needed for proper plasma membrane organization and cell wall synthesis. A conserved Cys motif in the first extracellular loop of fungal Sur7 proteins is similar to a characteristic motif of the claudin proteins that form tight junctions in animal cells, suggesting a common role for these tetraspanning membrane proteins in forming specialized plasma membrane domains.

  9. Characterization of two second-site mutations preventing wild type protein aggregation caused by a dominant negative PMA1 mutant.

    Directory of Open Access Journals (Sweden)

    Pilar Eraso

    Full Text Available The correct biogenesis and localization of Pma1 at the plasma membrane is essential for yeast growth. A subset of PMA1 mutations behave as dominant negative because they produce aberrantly folded proteins that form protein aggregates, which in turn provoke the aggregation of the wild type protein. One approach to understand this dominant negative effect is to identify second-site mutations able to suppress the dominant lethal phenotype caused by those mutant alleles. We isolated and characterized two intragenic second-site suppressors of the PMA1-D378T dominant negative mutation. We present here the analysis of these new mutations that are located along the amino-terminal half of the protein and include a missense mutation, L151F, and an in-frame 12bp deletion that eliminates four residues from Cys409 to Ala412. The results show that the suppressor mutations disrupt the interaction between the mutant and wild type enzymes, and this enables the wild type Pma1 to reach the plasma membrane.

  10. The Sur7 Protein Regulates Plasma Membrane Organization and Prevents Intracellular Cell Wall Growth in Candida albicans

    Science.gov (United States)

    Alvarez, Francisco J.; Douglas, Lois M.; Rosebrock, Adam

    2008-01-01

    The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S. cerevisiae. The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. cerevisiae, a C. albicans sur7Δ mutant displayed defects in endocytosis and morphogenesis. Septins and actin were mislocalized, and cell wall synthesis was very abnormal, including long projections of cell wall into the cytoplasm. Several phenotypes of the sur7Δ mutant are similar to the effects of inhibiting β-glucan synthase, suggesting that the abnormal cell wall synthesis is related to activation of chitin synthase activity seen under stress conditions. These results expand the roles of eisosomes by demonstrating that Sur7 is needed for proper plasma membrane organization and cell wall synthesis. A conserved Cys motif in the first extracellular loop of fungal Sur7 proteins is similar to a characteristic motif of the claudin proteins that form tight junctions in animal cells, suggesting a common role for these tetraspanning membrane proteins in forming specialized plasma membrane domains. PMID:18799621

  11. Adsorption mechanism of BMP-7 on hydroxyapatite (001) surfaces

    International Nuclear Information System (INIS)

    Zhou, Hailong; Wu, Tao; Dong, Xiuli; Wang, Qi; Shen, Jiawei

    2007-01-01

    Many properties and functions of bone-related proteins perform through the interface with the hydroxyapatite. However, the mechanism of difference of proteins adsorbing behaviors caused by the variation of calcium and phosphate ions on hydroxyapatite is still unclear at atomic level. In this work, we investigated the site-selective adhesion and the adsorption mechanism of protein BMP-7 to the hydroxyapatite surfaces in aqueous media during adsorption and desorption processes. Molecular dynamics (MD) and steered molecular dynamics (SMD) simulations combined with trajectory analysis were employed to give insight into the underlying behaviors of BMP-7 binding. The results suggest that the adsorption sites could be divided into two categories: COO - and NH 2 /NH3+. For COO - , the adsorption phenomenon is driven by the electrostatic interaction formed between the negative charged carboxylate groups and the Ca1 cations on the hydroxyapatite surface. While for NH 2 /NH3+, the interaction is through the intermolecular H-bonds between the N-containing groups and the phosphate on the hydroxyapatite surface

  12. Prediction of Pure Component Adsorption Equilibria Using an Adsorption Isotherm Equation Based on Vacancy Solution Theory

    DEFF Research Database (Denmark)

    Marcussen, Lis; Aasberg-Petersen, K.; Krøll, Annette Elisabeth

    2000-01-01

    An adsorption isotherm equation for nonideal pure component adsorption based on vacancy solution theory and the Non-Random-Two-Liquid (NRTL) equation is found to be useful for predicting pure component adsorption equilibria at a variety of conditions. The isotherm equation is evaluated successfully...... adsorption systems, spreading pressure and isosteric heat of adsorption are also calculated....

  13. Ultra Low Concentration Adsorption Equilibria

    National Research Council Canada - National Science Library

    Mahle, John J; Buettner, Leonard C; LeVan, M. D; Schindler, Bryan J

    2006-01-01

    .... Specifically this work focuses on novel experimental and modeling methods to characterize and predict at ultra-low chemical vapor concentrations the protection afforded by adsorption-based vapor filtration systems...

  14. Potential Theory of Multicomponent Adsorption

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1998-01-01

    We developed a theory of multicomponent adsorption on the basis of the potential concept originally suggested by Polanyi. The mixture is considered as a heterogeneous substance segregated in the external field emitted by the adsorbent. The same standard equation of state, with no additional fitting...... parameters, is used for the segregated and for the bulk phases. With this approach, few parameters are needed to correlate pure component adsorption isotherms. These parameters may be used to predict adsorption equilibria of multicomponent mixtures without additional adjustment. A connection between...... the potential theory and the spreading pressure concept is established, and problems of the theory consistency are studied. Numerical algorithms are suggested for evaluation of the segregated state of the mixture in the potential field of adsorption forces. Comparison with experimental data shows good agreement...

  15. Adsorption kinetics of surfactants on activated carbon

    Science.gov (United States)

    Arnelli; Aditama, WP; Fikriani, Z.; Astuti, Y.

    2018-04-01

    A study on the adsorption of both cationic and anionic surfactants using activated carbon as well as the investigation of the adsorption isotherms and adsorption kinetics has been conducted. The results showed that the adsorption of sodium lauryl sulfate (SLS) by activated carbon was Langmuir’s adsorption isotherm while its adsorption kinetics showed pseudo-second order with an adsorption rate constant of 2.23 x 103 g mg-1 hour-1. Meanwhile, the adsorption of HDTMA-Br by activated carbon showed that the isotherm adsorption tended to follow Freundlich’s isotherm and was pseudo-second order with an adsorption rate constant of 89.39 g mg-1 hour-1.

  16. Adsorption of amylase enzyme on ultrafiltration membranes

    DEFF Research Database (Denmark)

    Beier, Søren; Enevoldsen, Ann Dorrit; Kontogeorgis, Georgios

    2007-01-01

    A method to measure the static adsorption on membrane surfaces has been developed and described. The static adsorption of an amylase-F has been measured on two different ultrafiltration membranes, both with a cut-off value of 10 kDa (a PES membrane and the ETNA10PP membrane, which is a surface......-modified PVDF membrane). The adsorption follows the Langmuir adsorption theory. Thus, the static adsorption consists of monolayer coverage. The static adsorption is expressed both as a permeability drop and an adsorption resistance. From the adsorption isotherms the maximum static permeability drops...... and the maximum static adsorption resistances are determined. The maximum static permeability drop for the hydrophobic PES membrane is 75 % and the maximum static adsorption resistance is 0.014 m2hbar/L. The maximum static permeability drop for the hydrophilic surface-modified PVDF membrane (ETNA10PP) is 23...

  17. Characterization of DOM adsorption of CNTs by using excitation-emission matrix fluorescence spectroscopy and multiway analysis.

    Science.gov (United States)

    Peng, Mingguo; Li, Huajie; Li, Dongdong; Du, Erdeng; Li, Zhihong

    2017-06-01

    Carbon nanotubes (CNTs) were utilized to adsorb DOM in micro-polluted water. The characteristics of DOM adsorption on CNTs were investigated based on UV 254 , TOC, and fluorescence spectrum measurements. Based on PARAFAC (parallel factor) analysis, four fluorescent components were extracted, including one protein-like component (C4) and three humic acid-like components (C1, C2, and C3). The adsorption isotherms, kinetics, and thermodynamics of DOM adsorption on CNTs were further investigated. A Freundlich isotherm model fit the adsorption data well with high values of correlation. As a type of macro-porous and meso-porous adsorbent, CNTs preferably adsorb humic acid-like substances rather than protein-like substances. The increasing temperature will speed up the adsorption process. The self-organizing map (SOM) analysis further explains the fluorescent properties of water samples. The results provide a new insight into the adsorption behaviour of DOM fluorescent components on CNTs.

  18. Adsorption of antibiotics on microplastics.

    Science.gov (United States)

    Li, Jia; Zhang, Kaina; Zhang, Hua

    2018-06-01

    Microplastics and antibiotics are two classes of emerging contaminants with proposed negative impacts to aqueous ecosystems. Adsorption of antibiotics on microplastics may result in their long-range transport and may cause compound combination effects. In this study, we investigated the adsorption of 5 antibiotics [sulfadiazine (SDZ), amoxicillin (AMX), tetracycline (TC), ciprofloxacin (CIP), and trimethoprim (TMP)] on 5 types of microplastics [polyethylene (PE), polystyrene (PS), polypropylene (PP), polyamide (PA), and polyvinyl chloride (PVC)] in the freshwater and seawater systems. Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD) analysis revealed that microplastics have different surface characterizes and various degrees of crystalline. Adsorption isotherms demonstrated that PA had the strongest adsorption capacity for antibiotics with distribution coefficient (K d ) values ranged from 7.36 ± 0.257 to 756 ± 48.0 L kg -1 in the freshwater system, which can be attributed to its porous structure and hydrogen bonding. Relatively low adsorption capacity was observed on other four microplastics. The adsorption amounts of 5 antibiotics on PS, PE, PP, and PVC decreased in the order of CIP > AMX > TMP > SDZ > TC with K f correlated positively with octanol-water partition coefficients (Log K ow ). Comparing to freshwater system, adsorption capacity in seawater decreased significantly and no adsorption was observed for CIP and AMX. Our results indicated that commonly observed polyamide particles can serve as a carrier of antibiotics in the aquatic environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Bovine serum albumin adsorption onto functionalized polystyrene lattices: A theoretical modeling approach and error analysis

    Science.gov (United States)

    Beragoui, Manel; Aguir, Chadlia; Khalfaoui, Mohamed; Enciso, Eduardo; Torralvo, Maria José; Duclaux, Laurent; Reinert, Laurence; Vayer, Marylène; Ben Lamine, Abdelmottaleb

    2015-03-01

    The present work involves the study of bovine serum albumin adsorption onto five functionalized polystyrene lattices. The adsorption measurements have been carried out using a quartz crystal microbalance. Poly(styrene-co-itaconic acid) was found to be an effective adsorbent for bovine serum albumin molecule adsorption. The experimental isotherm data were analyzed using theoretical models based on a statistical physics approach, namely monolayer, double layer with two successive energy levels, finite multilayer, and modified Brunauer-Emmet-Teller. The equilibrium data were then analyzed using five different non-linear error analysis methods and it was found that the finite multilayer model best describes the protein adsorption data. Surface characteristics, i.e., surface charge density and number density of surface carboxyl groups, were used to investigate their effect on the adsorption capacity. The combination of the results obtained from the number of adsorbed layers, the number of adsorbed molecules per site, and the thickness of the adsorbed bovine serum albumin layer allows us to predict that the adsorption of this protein molecule can also be distinguished by monolayer or multilayer adsorption with end-on, side-on, and overlap conformations. The magnitudes of the calculated adsorption energy indicate that bovine serum albumin molecules are physisorbed onto the adsorbent lattices.

  20. In vitro investigation of sodium diclofenac adsorption on sucralfate.

    Science.gov (United States)

    Grimling, Bozena; Pluta, Janusz

    2006-01-01

    Adsorption of sodium diclofenac was investigated in the presence of sucralfate--a cytoprotective agent preventing gastropathy, adverse effect of diclofenac. Evaluation of adsorption was performed by means of a static method in vitro taking into account pH of the environment, temperature, concentration of the investigated agents and the form of sucralfate. Findings obtained prove that sodium diclofenac is adsorbed on sucralfate in all investigated pH ranges and the capability of sucralfate binding depends on its form, temperature and environmental pH. The highest binding was observed at pH 5.0 in the presence of sucralfate, which at this pH has the form of a suspension, while the lowest--at pH 1.5 in the presence of sucralfate in the form of paste. Low values of adsorption temperature of diclofenac as well as the relationship between the level of its adsorption and environmental pH are the dominating factors pointing to the physical and exothermic adsorption.

  1. KOH catalysed preparation of activated carbon aerogels for dye adsorption.

    Science.gov (United States)

    Ling, Sie King; Tian, H Y; Wang, Shaobin; Rufford, Thomas; Zhu, Z H; Buckley, C E

    2011-05-01

    Organic carbon aerogels (CAs) were prepared by a sol-gel method from polymerisation of resorcinol, furfural, and hexamethylenetetramine catalysed by KOH at around pH 9 using ambient pressure drying. The effect of KOH in the sol-gel on CA synthesis was studied. It was found that addition of KOH prior to the sol-gel polymerisation process improved thermal stability of the gel, prevented the crystallinity of the gel to graphite, increased the microporosity of CA and promoted activation of CA. The CAs prepared using the KOH catalyst exhibited higher porosity than uncatalysed prepared samples. Activation in CO(2) at higher temperature also enhanced the porosity of CAs. Adsorption tests indicated that the CAs were effective for both basic and acid dye adsorption and the adsorption increased with increasing surface area and pore volume. The kinetic adsorption of dyes was diffusion control and could be described by the second-order kinetic model. The equilibrium adsorption of dyes was higher than activated carbon. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Adsorption refrigeration technology theory and application

    CERN Document Server

    Wang, Ruzhu; Wu, Jingyi

    2014-01-01

    Gives readers a detailed understanding of adsorption refrigeration technology, with a focus on practical applications and environmental concerns Systematically covering the technology of adsorption refrigeration, this book provides readers with a technical understanding of the topic as well as detailed information on the state-of-the-art from leading researchers in the field. Introducing readers to background on the development of adsorption refrigeration, the authors also cover the development of adsorbents, various thermodynamic theories, the design of adsorption systems and adsorption refri

  3. Magnesium Presence Prevents Removal of Antigenic Nuclear-Associated Proteins from Bovine Pericardium for Heart Valve Engineering.

    Science.gov (United States)

    Dalgliesh, Ailsa J; Liu, Zhi Zhao; Griffiths, Leigh G

    2017-07-01

    Current heart valve prostheses are associated with significant complications, including aggressive immune response, limited valve life expectancy, and inability to grow in juvenile patients. Animal derived "tissue" valves undergo glutaraldehyde fixation to mask tissue antigenicity; however, chronic immunological responses and associated calcification still commonly occur. A heart valve formed from an unfixed bovine pericardium (BP) extracellular matrix (ECM) scaffold, in which antigenic burden has been eliminated or significantly reduced, has potential to overcome deficiencies of current bioprostheses. Decellularization and antigen removal methods frequently use sequential solutions extrapolated from analytical chemistry approaches to promote solubility and removal of tissue components from resultant ECM scaffolds. However, the extent to which such prefractionation strategies may inhibit removal of antigenic tissue components has not been explored. We hypothesize that presence of magnesium in prefractionation steps causes DNA precipitation and reduces removal of nuclear-associated antigenic proteins. Keeping all variables consistent bar the addition or absence of magnesium (2 mM magnesium chloride hexahydrate), residual BP ECM scaffold antigenicity and removed antigenicity were assessed, along with residual and removed DNA content, ECM morphology, scaffold composition, and recellularization potential. Furthermore, we used proteomic methods to determine the mechanism by which magnesium presence or absence affects scaffold residual antigenicity. This study demonstrates that absence of magnesium from antigen removal solutions enhances solubility and subsequent removal of antigenic nuclear-associated proteins from BP. We therefore conclude that the primary mechanism of action for magnesium removal during antigen removal processes is avoidance of DNA precipitation, facilitating solubilization and removal of nuclear-associated antigenic proteins. Future studies are

  4. The Sur7 Protein Regulates Plasma Membrane Organization and Prevents Intracellular Cell Wall Growth in Candida albicans

    OpenAIRE

    Alvarez, Francisco J.; Douglas, Lois M.; Rosebrock, Adam; Konopka, James B.

    2008-01-01

    The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S. cerevisiae. The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. cerevisiae, a C. albicans sur7Δ mutant displayed defects in endocytosis and morphogenes...

  5. mTORC1 activity as a determinant of cancer risk--rationalizing the cancer-preventive effects of adiponectin, metformin, rapamycin, and low-protein vegan diets.

    Science.gov (United States)

    McCarty, Mark F

    2011-10-01

    Increased plasma levels of adiponectin, metformin therapy of diabetes, rapamycin administration in transplant patients, and lifelong consumption of low-protein plant-based diets have all been linked to decreased risk for various cancers. These benefits may be mediated, at least in part, by down-regulated activity of the mTORC1 complex, a key regulator of protein translation. By boosting the effective availability of the translation initiator eIF4E, mTORC1 activity promotes the translation of a number of "weak" mRNAs that code for proteins, often up-regulated in cancer, that promote cellular proliferation, invasiveness, and angiogenesis, and that abet cancer promotion and chemoresistance by opposing apoptosis. Measures which inhibit eIF4E activity, either directly or indirectly, may have utility not only for cancer prevention, but also for the treatment of many cancers in which eIF4E drives malignancy. Since eIF4E is overexpressed in many cancers, strategies which target eIF4E directly--some of which are now being assessed clinically--may have the broadest efficacy in this regard. Many of the "weak" mRNAs coding for proteins that promote malignant behavior or chemoresistance are regulated transcriptionally by NF-kappaB and/or Stat3, which are active in a high proportion of cancers; thus, regimens concurrently targeting eIF4E, NF-kappaB, and Stat3 may suppress these proteins at both the transcriptional and translational levels, potentially achieving a very marked reduction in their expression. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Schiff Base Metal Derivatives Enhance the Expression of HSP70 and Suppress BAX Proteins in Prevention of Acute Gastric Lesion

    Directory of Open Access Journals (Sweden)

    Shahram Golbabapour

    2013-01-01

    Full Text Available Schiff base complexes have appeared to be promising in the treatment of different diseases and disorders and have drawn a lot of attention to their biological activities. This study was conducted to evaluate the regulatory effect of Schiff base metal derivatives on the expression of heat shock proteins (HSP 70 and BAX in protection against acute haemorrhagic gastric ulcer in rats. Rats were assigned to 6 groups of 6 rats: the normal control (Tween 20 5% v/v, 5 mL/kg, the positive control (Tween 20 5% v/v, 5 mL/kg, and four Schiff base derivative groups named Schiff_1, Schiff_2, Schiff_3, and Schiff_4 (25 mg/kg. After 1 h, all of the groups received ethanol 95% (5 mL/kg but the normal control received Tween 20 (Tween 20 5% v/v, 5 mL/kg. The animals were euthanized after 60 min and the stomachs were dissected for histology (H&E, immunohistochemistry, and western blot analysis against HSP70 and BAX proteins. The results showed that the Schiff base metal derivatives enhanced the expression of HSP70 and suppressed the expression of BAX proteins during their gastroprotection against ethanol-induced gastric lesion in rats.

  7. Schiff base metal derivatives enhance the expression of HSP70 and suppress BAX proteins in prevention of acute gastric lesion.

    Science.gov (United States)

    Golbabapour, Shahram; Gwaram, Nura Suleiman; Al-Obaidi, Mazen M Jamil; Soleimani, A F; Ali, Hapipah Mohd; Abdul Majid, Nazia

    2013-01-01

    Schiff base complexes have appeared to be promising in the treatment of different diseases and disorders and have drawn a lot of attention to their biological activities. This study was conducted to evaluate the regulatory effect of Schiff base metal derivatives on the expression of heat shock proteins (HSP) 70 and BAX in protection against acute haemorrhagic gastric ulcer in rats. Rats were assigned to 6 groups of 6 rats: the normal control (Tween 20 5% v/v, 5 mL/kg), the positive control (Tween 20 5% v/v, 5 mL/kg), and four Schiff base derivative groups named Schiff_1, Schiff_2, Schiff_3, and Schiff_4 (25 mg/kg). After 1 h, all of the groups received ethanol 95% (5 mL/kg) but the normal control received Tween 20 (Tween 20 5% v/v, 5 mL/kg). The animals were euthanized after 60 min and the stomachs were dissected for histology (H&E), immunohistochemistry, and western blot analysis against HSP70 and BAX proteins. The results showed that the Schiff base metal derivatives enhanced the expression of HSP70 and suppressed the expression of BAX proteins during their gastroprotection against ethanol-induced gastric lesion in rats.

  8. Uncovering methods for the prevention of protein aggregation and improvement of product quality in a transient expression system.

    Science.gov (United States)

    Estes, Bram; Hsu, Yueh-Rong; Tam, Lei-Ting; Sheng, Jackie; Stevens, Jennitte; Haldankar, Raj

    2015-01-01

    Mammalian expression systems are used routinely for the production of recombinant proteins as therapeutic molecules as well as research tools. Transient expression has become increasingly popular in recent years due to its rapid timeline and improvements in expression level. While improvements to transient expression systems have focused mainly on the level of protein expression, the aspect of protein quality has received little attention. The removal of undesirable products, such as aggregation, depends primarily on purification, requiring additional cumbersome steps, which can lead to a lower product yield and longer timelines. In this study, we show that reducing the level of transcription by transfecting at a lower gene dose improves the quality of secreted molecules prone to aggregation. For gene dosing to have this effect, it is critical for the carrier DNA to be an empty vector containing the same elements as the gene containing plasmid. This approach can be used in combination with a temperature shift to hypothermic conditions during production to enhance the effect. The observed improvements not only minimized aggregation levels, but also generated products with overall superior quality, including more homogeneous signal peptide cleavage and N-linked glycosylation profiles. These techniques have produced a similar improvement in product quality with a variety of other molecules, suggesting that this may be a general approach to enhance product quality from transient expression systems. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers.

  9. Adsorption and spectroscopic characterization of lactoferrin on hydroxyapatite nanocrystals.

    Science.gov (United States)

    Iafisco, Michele; Di Foggia, Michele; Bonora, Sergio; Prat, Maria; Roveri, Norberto

    2011-01-28

    Lactoferrin (LF), a well-characterized protein of blood plasma and milk with antioxidant, cariostatic, anticarcinogenic and anti-inflammatory properties, has been adsorbed onto biomimetic hydroxyapatite (HA) nanocrystals at two different pH values (7.4 and 9.0). The interaction was herein investigated by spectroscopic, thermal and microscopic techniques. The positive electrostatic surface potential of LF at pH 7.4 allows a strong surface interaction with the slightly negative HA nanocrystals and avoids the protein-protein interaction, leading to the formation of a coating protein monolayer. In contrast, at pH 9.0 the surface potential of LF is a mix of negative and positive zones favouring the protein-protein interaction and reducing the interaction with HA nanocrystals; as a result a double layer of coating protein was formed. These experimental findings are supported by the good fittings of the adsorption isotherms by different theoretical models according to Langmuir, Freundlich and Langmuir-Freundlich models. The nanosized HA does not appreciably affect the conformation of the adsorbed protein. In fact, using FT-Raman and FT-IR, we found that after adsorption the protein was only slightly unfolded with a small fraction of the α-helix structure being converted into turn, while the β-sheet content remained almost unchanged. The bioactive surface of HA functionalized with LF could be utilized to improve the material performance towards the biological environment for biomedical applications.

  10. Preventing secondary cases of invasive meningococcal capsular group B (MenB) disease using a recently-licensed, multi-component, protein-based vaccine (Bexsero(®)).

    Science.gov (United States)

    Ladhani, Shamez N; Cordery, Rebecca; Mandal, Sema; Christensen, Hannah; Campbell, Helen; Borrow, Ray; Ramsay, Mary E

    2014-11-01

    To assess the potential use of a protein-based meningococcal group B (MenB) vaccine (Bexsero(®)) in addition to antibiotic chemoprophylaxis for preventing secondary cases. Published studies on the risk of secondary meningococcal infections were used to estimate the numbers needed to vaccinate (NNV) with Bexsero(®) to prevent a secondary case in household and educational settings. Most secondary cases occur within a few days of diagnosis in the index case. Unlike conjugate vaccines, early protection offered after a single dose of Bexsero(®) is likely to be low, particularly in young children, who are at higher risk of secondary infection. NNV was dependent on predicted meningococcal strain coverage, estimated onset of protection after one Bexsero(®) dose and estimated vaccine efficacy. Even in the most favourable scenario where we assume the vaccine is administered within 4 days of the index case and prevents 90% of cases occurring after 14 days, the NNV for household contacts was >1000. NNV in educational settings was much higher. The estimated NNV should be taken into account when deciding policy to recommend Bexsero(®) for close contacts of single cases in household or educational settings. Bexsero(®) may have a protective role in clusters and outbreaks. Copyright © 2014 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  11. Graphitic Carbon Materials Tailored for the Rapid Adsorption of Biomolecules

    Science.gov (United States)

    Pescatore, Nicholas A.

    Sepsis is an overactive inflammatory response to an infection, with 19 million cases estimated worldwide and causing organ dysfunction if left untreated. Three pro-inflammatory cytokines are seen from literature review as vital biomarkers for sepsis and are interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha), which have the potential to be removed by hemoperfusion. This thesis examines carbon nanomaterials for their adsorption capabilities in the search for an optimal material for blood cleansing hemoperfusion application, such as mediating the effects of sepsis. Non-porous and porous carbon polymorphs and their properties are investigated in this thesis for their protein adsorption capabilities. Polymer-derived mesoporous carbons were compared to non-porous graphene nanoplatelets (GNP's) to observe changes in adsorption capacity for cytokines between porous and non-porous materials. GNP's were functionalized via high temperature vacuum annealing, air oxidation, acid oxidation and amination treatments to understand the effect of surface chemistry on adsorption. For practical use in a hemoperfusion column, polymer-derived carbon beads and composite materials such as cryogel and PTFE-GNP composites were designed and tested for their adsorption capacity. At concentrations of IL-6, IL-8, and TNF-alpha seen in septic patients, these cytokines were completely removed from the blood after 5 minutes of incubation with GNP's. Overall, a low-cost, scalable carbon adsorbent was found to provide a novel approach of rapidly removing pro-inflammatory cytokines from septic patients.

  12. High Protein Intake Does Not Prevent Low Plasma Levels of Conditionally Essential Amino Acids in Very Preterm Infants Receiving Parenteral Nutrition.

    Science.gov (United States)

    Morgan, Colin; Burgess, Laura

    2017-03-01

    We have shown that increasing protein intake using a standardized, concentrated, added macronutrients parenteral (SCAMP) nutrition regimen improves head growth in very preterm infants (VPIs) compared with a control parenteral nutrition (PN) regimen. VPIs are at risk of conditionally essential amino acid (CEAA) deficiencies because of current neonatal PN amino acid (AA) formulations. We hypothesized that the SCAMP regimen would prevent low plasma levels of CEAAs. To compare the plasma AA profiles at approximately day 9 of life in VPIs receiving SCAMP vs a control PN regimen. VPIs (parenteral and enteral protein, energy, and individual AA intake and the first plasma AA profile. Plasma profiles of the 20 individual protogenic AA levels were measured using ion exchange chromatography. Plasma AA profiles were obtained at median (interquartile range [IQR]) age of 9 (8-10) days in both SCAMP (n = 59) and control (n = 67) groups after randomizing 150 VPIs. Median (IQR) plasma levels of individual essential AAs were higher than the reference population mean (RPM) in both groups, especially for threonine. SCAMP infants had higher plasma levels of essential AAs than did the controls. Median (IQR) plasma levels of glutamine, arginine, and cysteine (CEAAs) were lower than the RPM in both groups. Plasma AA levels in PN-dependent VPIs indicate there is an imbalance in essential and CEAA provision in neonatal PN AA formulations that is not improved by increasing protein intake.

  13. Far-infrared radiation protects viability in a cell model of Spinocerebellar Ataxia by preventing polyQ protein accumulation and improving mitochondrial function.

    Science.gov (United States)

    Chang, Jui-Chih; Wu, Shey-Lin; Hoel, Fredrik; Cheng, Yu-Shan; Liu, Ko-Hung; Hsieh, Mingli; Hoel, August; Tronstad, Karl Johan; Yan, Kuo-Chia; Hsieh, Ching-Liang; Lin, Wei-Yong; Kuo, Shou-Jen; Su, Shih-Li; Liu, Chin-San

    2016-07-29

    Far infrared radiation (FIR) is currently investigated as a potential therapeutic strategy in various diseases though the mechanism is unknown. Presently, we tested if FIR mediates beneficial effects in a cell model of the neurodegenerative disease spinocerebellar ataxia type 3 (SCA3). SCA3 is caused by a mutation leading to an abnormal polyglutamine expansion (PolyQ) in ataxin-3 protein. The consequent aggregation of mutant ataxin-3 results in disruption of vital cell functions. In this study, neuroblastoma cells (SK-N-SH) was transduced to express either non-pathogenic ataxin-3-26Q or pathogenic ataxin-3-78Q proteins. The cells expressing ataxin-3-78Q demonstrated decreased viability, and increased sensitivity to metabolic stress in the presence rotenone, an inhibitor of mitochondrial respiration. FIR exposure was found to protect against these effects. Moreover, FIR improved mitochondrial respiratory function, which was significantly compromised in ataxin-3-78Q and ataxin-3-26Q expressing cells. This was accompanied by decreased levels of mitochondrial fragmentation in FIR treated cells, as observed by fluorescence microscopy and protein expression analysis. Finally, the expression profile LC3-II, Beclin-1 and p62 suggested that FIR prevent the autophagy inhibiting effects observed in ataxin-3-78Q expressing cells. In summary, our results suggest that FIR have rescuing effects in cells expressing mutated pathogenic ataxin-3, through recovery of mitochondrial function and autophagy.

  14. Scutellaria barbata attenuates diabetic retinopathy by preventing retinal inflammation and the decreased expression of tight junction protein

    Directory of Open Access Journals (Sweden)

    Xi-Yu Mei

    2017-06-01

    Full Text Available AIM: To observe the attenuation of ethanol extract of Herba Scutellaria barbata (SE against diabetic retinopathy (DR and its engaged mechanism. METHODS: C57BL/6J mice were intraperitoneally injected with streptozotocin (STZ, 55 mg/kg for 5 consecutive days to induce diabetes. The diabetic mice were orally given with SE (100, 200 mg/kg for 1mo at 1mo after STZ injection. Blood-retinal barrier (BRB breakdown was detected by using Evans blue permeation assay. Real-time polymerase chain reaction (RT-PCR, Western blot and immunofluorescence staining were used to detect mRNA and protein expression. Enzyme-linked immunosorbent assay (ELISA was used to detect serum contents of tumor necrosis factor-α (TNF-α and interleukin (IL-1β. RESULTS: SE (100, 200 mg/kg reversed the breakdown of BRB in STZ-induced diabetic mice. The decreased expression of retinal claudin-1 and claudin-19, which are both tight junction (TJ proteins, was reversed by SE. SE decreased the increased serum contents and retinal mRNA expression of TNF-α and IL-1β. SE also decreased the increased retinal expression of intercellular cell adhesion molecule-1 (ICAM-1. SE reduced the increased phosphorylation of nuclear factor kappa B (NFκB p65 and its subsequent nuclear translocation in retinas from STZ-induced diabetic mice. Results of Western blot and retinal immunofluorescence staining of ionized calcium-binding adapter molecule 1 (Iba1 demonstrated that SE abrogated the activation of microglia cells in STZ-induced diabetic mice. CONCLUSION: SE attenuates the development of DR by inhibiting retinal inflammation and restoring the decreased expression of TJ proteins including claudin-1 and claudin-19.

  15. [Dietary prevention of protein-energy malnutrition during early postoperative period in elderly patients with gastroduodenal diseases].

    Science.gov (United States)

    Baranovskiĭ, A Iu; Protopopova, O B

    2012-01-01

    The modified diet of postoperative rehabilitation program in elderly patients with gastroduodenal ulcers and prognosis of development of protein-energy malnutrition (PEM) is presented. It is shown that early initiated special diet in postoperative period, blocks mechanisms of malnutrition and can significantly improve the functional status of the small intestine and activate, thus, membrane digestion, which leads to normalization of all types of metabolism in elderly patients. In comparison with control group, where 72% of patients in postoperative period had malnutrition, malnutrition in the study group revealed a mild degree in only 17.3% of patients.

  16. Sibiriline, a new small chemical inhibitor of receptor-interacting protein kinase 1, prevents immune-dependent hepatitis.

    Science.gov (United States)

    Le Cann, Fabienne; Delehouzé, Claire; Leverrier-Penna, Sabrina; Filliol, Aveline; Comte, Arnaud; Delalande, Olivier; Desban, Nathalie; Baratte, Blandine; Gallais, Isabelle; Piquet-Pellorce, Claire; Faurez, Florence; Bonnet, Marion; Mettey, Yvette; Goekjian, Peter; Samson, Michel; Vandenabeele, Peter; Bach, Stéphane; Dimanche-Boitrel, Marie-Thérèse

    2017-09-01

    Necroptosis is a regulated form of cell death involved in several disease models including in particular liver diseases. Receptor-interacting protein kinases, RIPK1 and RIPK3, are the main serine/threonine kinases driving this cell death pathway. We screened a noncommercial, kinase-focused chemical library which allowed us to identify Sibiriline as a new inhibitor of necroptosis induced by tumor necrosis factor (TNF) in Fas-associated protein with death domain (FADD)-deficient Jurkat cells. Moreover, Sib inhibits necroptotic cell death induced by various death ligands in human or mouse cells while not protecting from caspase-dependent apoptosis. By using competition binding assay and recombinant kinase assays, we demonstrated that Sib is a rather specific competitive RIPK1 inhibitor. Molecular docking analysis shows that Sib is trapped closed to human RIPK1 adenosine triphosphate-binding site in a relatively hydrophobic pocket locking RIPK1 in an inactive conformation. In agreement with its RIPK1 inhibitory property, Sib inhibits both TNF-induced RIPK1-dependent necroptosis and RIPK1-dependent apoptosis. Finally, Sib protects mice from concanavalin A-induced hepatitis. These results reveal the small-molecule Sib as a new RIPK1 inhibitor potentially of interest for the treatment of immune-dependent hepatitis. © 2017 Federation of European Biochemical Societies.

  17. Prevention of early postnatal hyperalimentation protects against activation of transforming growth factor-β/bone morphogenetic protein and interleukin-6 signaling in rat lungs after intrauterine growth restriction.

    Science.gov (United States)

    Alcázar, Miguel Angel Alejandre; Dinger, Katharina; Rother, Eva; Östreicher, Iris; Vohlen, Christina; Plank, Christian; Dötsch, Jörg

    2014-12-01

    Intrauterine growth restriction (IUGR) is intimately linked with postnatal catch-up growth, leading to impaired lung structure and function. However, the impact of catch-up growth induced by early postnatal hyperalimentation (HA) on the lung has not been addressed to date. The aim of this study was to investigate whether prevention of HA subsequent to IUGR protects the lung from 1) deregulation of the transforming growth factor-β(TGF-β)/bone morphogenetic protein (BMP) pathway, 2) activation of interleukin (IL)-6 signaling, and 3) profibrotic processes. IUGR was induced in Wistar rats by isocaloric protein restriction during gestation by feeding a control (Co) or a low-protein diet with 17% or 8% casein, respectively. On postnatal day 1 (P1), litters from both groups were randomly reduced to 6 pups per dam to induce HA or adjusted to 10 pups and fed with standard diet: Co, Co with HA (Co-HA), IUGR, and IUGR with HA (IUGR-HA). Birth weights in rats after IUGR were lower than in Co rats (P < 0.05). HA during lactation led to accelerated body weight gain from P1 to P23 (Co vs. Co-HA, IUGR vs. IUGR-HA; P < 0.05). At P70, prevention of HA after IUGR protected against the following: 1) activation of both TGF-β [phosphorylated SMAD (pSMAD) 2; plasminogen activator inhibitor 1 (Pai1)] and BMP signaling [pSMAD1; inhibitor of differentiation (Id1)] compared with Co (P < 0.05) and Co or IUGR (P < 0.05) rats, respectively; 2) greater mRNA expression of interleukin (Il) 6 and Il13 (P < 0.05) as well as activation of signal transducer and activator of transcription 3 (STAT3) signaling (P < 0.05) after IUGR-HA; and 3) greater gene expression of collagen Iα1 and osteopontin (P < 0.05) and increased deposition of bronchial subepithelial connective tissue in IUGR-HA compared with Co and IUGR rats. Moreover, HA had a significant additive effect (P < 0.05) on the increased enhanced pause (indicator of airway resistance) in the IUGR group (P < 0.05) at P70. This study demonstrates

  18. Adsorption of cellulases onto sugar beet shreds and modeling of the experimental data

    Directory of Open Access Journals (Sweden)

    Ivetić Darjana Ž.

    2014-01-01

    Full Text Available This study investigated the adsorption of cellulases onto sugar beet shreds. The experiments were carried out using untreated, as well as dried and not dried dilute acid and steam pretreated sugar beet shreds at different initial enzyme loads. Both dilute acid and steam pretreatment were beneficial in respect of cellulases adsorption providing 8 and 9 times higher amounts of adsorbed proteins, respectively, in comparison to the results obtained with the untreated substrate. Although the use of higher solids load enabled by drying of pretreated substrates, could be beneficial for process productivity, at the same time it decreases the adsorption of enzymes. The obtained experimental data were fitted to five adsorption models, and the Langmuir model having the lowest residual sum of squares was used for the determination of adsorption parameters which were used to calculate the strength of cellulases binding to the substrates.[Projekat Ministarstva nauke Republike Srbije, br. TR 31002

  19. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  20. A biological oil adsorption filter

    International Nuclear Information System (INIS)

    Pasila, A.

    2005-01-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  1. Arsenite adsorption on goethite at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kersten, Michael [Environmental Geochemistry Group, Institute of Geosciences, Johannes Gutenberg-University, Mainz 55099 (Germany)], E-mail: kersten@uni-mainz.de; Vlasova, Nataliya [Environmental Geochemistry Group, Institute of Geosciences, Johannes Gutenberg-University, Mainz 55099 (Germany)

    2009-01-15

    Experimental closed-system {delta}T acid-base titrations between 10 deg. C and 75 deg. C were used to constrain a temperature-dependent 1-pK basic Stern model of the goethite surface complexation reactions. Experimental data for the temperature dependence of pH{sub PZC} determined by the one-term Van't Hoff extrapolation yield a value for goethite surface protonation enthalpy of -49.6 kJ mol{sup -1} in good agreement with literature data. Batch titration data between 10 deg. C and 75 deg. C with arsenite concentrations between 10 {mu}M and 100 {mu}M yield adsorption curves, which increases with pH, peak at a pH of 9, and decrease at higher pH values. The slope of this bend becomes steeper with increasing temperature. A 1-pK charge distribution model in combination with a basic Stern layer option could be established for the pH-dependent arsenite adsorption. Formation of two inner-sphere bidentate surface complexes best matched the experimental data in agreement with published EXAFS spectroscopic information. The temperature behaviour of the thus derived intrinsic equilibrium constants can be well represented by the linear Van't Hoff logK{sub T}{sup int} vs. 1/T plot. Adsorption of arsenite on the goethite surface is exothermic (negative {delta}{sub r}H{sub 298} values) and therefore becomes weaker with increasing temperature. Application of the new constants with the aqueous speciation code VMINTEQ predicts that the As(III) concentration in presence of goethite sorbent decreases by 10 times once the hydrothermal solution is cooled from 99 deg. C to 1 deg. C. The model curve matches data from a natural thermal water spring system. The increase of adsorption efficiency for As along the temperature gradient may well serve as an additional process to prevent ecosystem contamination by As-rich water seepage from geothermal energy generation facilities.

  2. The rs1800629 polymorphism in the TNF gene interacts with physical activity on the changes in C-reactive protein levels in the Finnish Diabetes Prevention Study

    DEFF Research Database (Denmark)

    Oskari Kilpeläinen, Tuomas; Laaksonen, D E; Lakka, T A

    2010-01-01

    /L) baseline CRP levels ( P = 0.034 for interaction). Carriers of the GG genotype showed a greater decrease in CRP with increasing physical activity than the individuals with the A allele. No interaction between the rs1800795 SNP in IL6 and changes in moderate-to-vigorous physical activity on the 1-year change......Physical activity exerts anti-inflammatory effects, but genetic variation may modify its influence. In particular, the rs1800629 single-nucleotide polymorphism (SNP) in the tumor necrosis factor ( TNF) gene and the rs1800795 SNP in the interleukin-6 ( IL6) gene have been found to modify the effect...... of exercise training on circulating levels of C-reactive protein (CRP) and IL-6, respectively. We assessed whether rs1800629 and rs1800795 modified the effect of moderate-to-vigorous physical activity on changes in serum levels of high-sensitivity CRP and IL-6 in the Finnish Diabetes Prevention Study (DPS...

  3. Adsorption studies on Pt(111)

    International Nuclear Information System (INIS)

    Hopster, H.

    1977-06-01

    The adsorption of O 2 , CO, and C 2 H 2 as well as the CO oxidation on Pt(111) were studied by high-resolution electron spectroscopy. Using a platinum monocrystal sample with a contonuous stage density, the adhesion coefficient for O 2 and the reaction probability for CO were determined as a function of stage density and oxygen cover by measuring the oxygen cover and its time behaviour. The study of vibrations of adsorbed CO showed that CO is bound in linear form on two different adsorption sites. The adsorption of acetylene was studied at 140 K and 300 K. The frequencies of the C-H stretching and flexural vibrations as well as the C-C-H bonding angle were determined. (orig./GSC) [de

  4. Theoretical insight of adsorption cooling

    KAUST Repository

    Chakraborty, Anutosh

    2011-06-03

    This letter proposes and presents a thermodynamic formulation to calculate the energetic performances of an adsorption cooler as a function of pore widths and volumes of solid adsorbents. The simulated results in terms of the coefficient of performance are validated with experimental data. It is found from the present analysis that the performance of an adsorption cooling device is influenced mainly by the physical characteristics of solid adsorbents, and the characteristics energy between the adsorbent-adsorbate systems. The present study confirms that there exists a special type of silicagel having optimal physical characteristics that allows us to obtain the best performance.

  5. Theoretical insight of adsorption cooling

    KAUST Repository

    Chakraborty, Anutosh; Leong, Kai Choong; Thu, Kyaw; Saha, Bidyut Baran; Ng, Kim Choon

    2011-01-01

    This letter proposes and presents a thermodynamic formulation to calculate the energetic performances of an adsorption cooler as a function of pore widths and volumes of solid adsorbents. The simulated results in terms of the coefficient of performance are validated with experimental data. It is found from the present analysis that the performance of an adsorption cooling device is influenced mainly by the physical characteristics of solid adsorbents, and the characteristics energy between the adsorbent-adsorbate systems. The present study confirms that there exists a special type of silicagel having optimal physical characteristics that allows us to obtain the best performance.

  6. Potential Theory of Multicomponent Adsorption

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1998-01-01

    We developed a theory of multicomponent adsorption on the basis of the potential concept originally suggested by Polanyi. The mixture is considered as a heterogeneous substance segregated in the external field emitted by the adsorbent. The same standard equation of state, with no additional fitting...... and high degree of predictability of the theory developed....... the potential theory and the spreading pressure concept is established, and problems of the theory consistency are studied. Numerical algorithms are suggested for evaluation of the segregated state of the mixture in the potential field of adsorption forces. Comparison with experimental data shows good agreement...

  7. Physical activity in the prevention and treatment of diseases of affluence – the key role of AMP-activated protein kinase (AMPK

    Directory of Open Access Journals (Sweden)

    Ewa Grochowska

    2014-09-01

    Full Text Available In developed countries, we can observe an increasing number of people with obesity, type 2 diabetes, dyslipidemia, hypertension and arteriosclerosis. The main reason for this phenomenon is the abnormal energy balance due to sedentary lifestyles. Cardiovascular diseases are the leading cause of death in many countries around the world, nowadays. In this paper, the impact of physical activity on the effectiveness of treatment and prevention of metabolic diseases and cancer is considered. Exercise is one of the factors activating 5’AMP-activated protein kinase (AMPK. This enzyme is crucial in maintaining the energy balance of the cell and the entire organism, and its activation results in excluding the anabolic and switching on the catabolic processes. It is believed that the activation of AMPK is responsible for most of the positive effects resulting from physical exercise. Although there are pharmacological methods of activation of this enzyme, they seem to be not as effective as physical exercise. Therefore, physical activity should be the most important form of prevention and treatment of metabolic diseases.

  8. Oral administration of Lactococcus lactis-expressing heat shock protein 65 and tandemly repeated IA2P2 prevents type 1 diabetes in NOD mice.

    Science.gov (United States)

    Liu, Kun-Feng; Liu, Xiao-Rui; Li, Guo-Liang; Lu, Shi-Ping; Jin, Liang; Wu, Jie

    2016-06-01

    Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by the destruction of insulin-secreting β cells upon autoreactive T cell attack. Oral administration of autoantigens is an attractive approach to treating T1DM, but an effective carrier should be used in order to protect antigens. Lactococcus lactis, a safe engineering strain, was used for this task in the present study. Two recombinant L. lactis expressing protein HSP65-6IA2P2 were used and be investigated the effects and mechanisms against T1DM in NOD mice. Our findings demonstrate that recombinant L. lactis strains can successfully both deliver antigens to intestinal mucosa and maintain the epitopes for a long time in NOD mice. Oral administration of recombinant L. lactis could prevent hyperglycemia, improve glucose tolerance, and reduce insulitis by inhibiting antigen-specific proliferation of T cells, augmenting regulatory immune reactions, and balancing ratios of Th17/Tregs and Th1/Th2. These results prove that orally administrated L. lactis expressing HSP65-6IA2P2 is an effective approach for the prevention of T1DM in NOD mice. Copyright © 2016 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

  9. Secretion of biologically active pancreatitis-associated protein I (PAP) by genetically modified dairy Lactococcus lactis NZ9000 in the prevention of intestinal mucositis.

    Science.gov (United States)

    Carvalho, Rodrigo D; Breyner, Natalia; Menezes-Garcia, Zelia; Rodrigues, Nubia M; Lemos, Luisa; Maioli, Tatiane U; da Gloria Souza, Danielle; Carmona, Denise; de Faria, Ana M C; Langella, Philippe; Chatel, Jean-Marc; Bermúdez-Humarán, Luis G; Figueiredo, Henrique C P; Azevedo, Vasco; de Azevedo, Marcela S

    2017-02-13

    Mucositis is one of the most relevant gastrointestinal inflammatory conditions in humans, generated by the use of chemotherapy drugs, such as 5-fluoracil (5-FU). 5-FU-induced mucositis affects 80% of patients undergoing oncological treatment causing mucosal gut dysfunctions and great discomfort. As current therapy drugs presents limitations in alleviating mucositis symptoms, alternative strategies are being pursued. Recent studies have shown that the antimicrobial pancreatitis-associated protein (PAP) has a protective role in intestinal inflammatory processes. Indeed, it was demonstrated that a recombinant strain of Lactococcus lactis expressing human PAP (LL-PAP) could prevent and improve murine DNBS-induced colitis, an inflammatory bowel disease (IBD) that causes severe inflammation of the colon. Hence, in this study we sought to evaluate the protective effects of LL-PAP on 5-FU-induced experimental mucositis in BALB/c mice as a novel approach to treat the disease. Our results show that non-recombinant L. lactis NZ9000 have antagonistic activity, in vitro, against the enteroinvasive gastrointestinal pathogen L. monocytogenes and confirmed PAP inhibitory effect against Opportunistic E. faecalis. Moreover, L. lactis was able to prevent histological damage, reduce neutrophil and eosinophil infiltration and secretory Immunoglobulin-A in mice injected with 5-FU. Recombinant lactococci carrying antimicrobial PAP did not improve those markers of inflammation, although its expression was associated with villous architecture preservation and increased secretory granules density inside Paneth cells in response to 5-FU inflammation. We have demonstrated for the first time that L. lactis NZ9000 by itself, is able to prevent 5-FU-induced intestinal inflammation in BALB/c mice. Moreover, PAP delivered by recombinant L. lactis strain showed additional protective effects in mice epithelium, revealing to be a promising strategy to treat intestinal mucositis.

  10. Controlling adsorption and passivation properties of bovine serum albumin on silica surfaces by ionic strength modulation and cross-linking.

    Science.gov (United States)

    Park, Jae Hyeon; Sut, Tun Naw; Jackman, Joshua A; Ferhan, Abdul Rahim; Yoon, Bo Kyeong; Cho, Nam-Joon

    2017-03-29

    Understanding the physicochemical factors that influence protein adsorption onto solid supports holds wide relevance for fundamental insights into protein structure and function as well as for applications such as surface passivation. Ionic strength is a key parameter that influences protein adsorption, although how its modulation might be utilized to prepare well-coated protein adlayers remains to be explored. Herein, we investigated how ionic strength can be utilized to control the adsorption and passivation properties of bovine serum albumin (BSA) on silica surfaces. As protein stability in solution can influence adsorption kinetics, the size distribution and secondary structure of proteins in solution were first characterized by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and circular dichroism (CD) spectroscopy. A non-monotonic correlation between ionic strength and protein aggregation was observed and attributed to colloidal agglomeration, while the primarily α-helical character of the protein in solution was maintained in all cases. Quartz crystal microbalance-dissipation (QCM-D) experiments were then conducted in order to track protein adsorption onto silica surfaces as a function of ionic strength, and the measurement responses indicated that total protein uptake at saturation coverage is lower with increasing ionic strength. In turn, the QCM-D data and the corresponding Voigt-Voinova model analysis support that the surface area per bound protein molecule is greater with increasing ionic strength. While higher protein uptake under lower ionic strengths by itself did not result in greater surface passivation under subsequent physiologically relevant conditions, the treatment of adsorbed protein layers with a gluteraldehyde cross-linking agent stabilized the bound protein in this case and significantly improved surface passivation. Collectively, our findings demonstrate that ionic strength modulation influences BSA adsorption

  11. Fast gas adsorption measurements for complicated adsorption mechanisms

    NARCIS (Netherlands)

    Robens, E.; Poulis, J.A.; Massen, C.H.

    2000-01-01

    Jäntti introduced a method to reduce the time required for the stepwise measurement of adsorption isotherms. After each pressure change he measured the adsorbed mass three times and calculated its equilibrium value at the new pressure. In the present paper, we discuss the applicability of this

  12. Prevention of adverse events of interferon γ gene therapy by gene delivery of interferon γ-heparin-binding domain fusion protein in mice

    Directory of Open Access Journals (Sweden)

    Mitsuru Ando

    2014-01-01

    Full Text Available Sustained gene delivery of interferon (IFN γ can be an effective treatment, but our previous study showed high levels of IFNγ-induced adverse events, including the loss of body weight. These unwanted events could be reduced by target-specific delivery of IFNγ after in vivo gene transfer. To achieve this, we selected the heparin-binding domain (HBD of extracellular superoxide dismutase as a molecule to anchor IFNγ to the cell surface. We designed three IFNγ derivatives, IFNγ-HBD1, IFNγ-HBD2, and IFNγ-HBD3, each of which had 1, 2, or 3 HBDs, respectively. Each plasmid-encoding fusion proteins was delivered to the liver, a model target in this study, by hydrodynamic tail vein injection. The serum concentration of IFNγ-HBD2 and IFNγ-HBD3 after gene delivery was lower than that of IFNγ or IFNγ-HBD1. Gene delivery of IFNγ-HBD2, but not of IFNγ-HBD3, effectively increased the mRNA expression of IFNγ-inducible genes in the liver, suggesting liver-specific distribution of IFNγ-HBD2. Gene delivery of IFNγ-HBD2-suppressed tumor growth in the liver as efficiently as that of IFNγ with much less symptoms of adverse effects. These results indicate that the adverse events of IFNγ gene transfer can be prevented by gene delivery of IFNγ-HBD2, a fusion protein with high cell surface affinity.

  13. Prevention of hepatitis C virus infection in chimpanzees by hyperimmune serum against the hypervariable region 1 of the envelope 2 protein.

    Science.gov (United States)

    Farci, P; Shimoda, A; Wong, D; Cabezon, T; De Gioannis, D; Strazzera, A; Shimizu, Y; Shapiro, M; Alter, H J; Purcell, R H

    1996-12-24

    The identification of the neutralization domains of hepatitis C virus (HCV) is essential for the development of an effective vaccine. Here, we show that the hypervariable region 1 (HVR1) of the envelope 2 (E2) protein is a critical neutralization domain of HCV. Neutralization of HCV in vitro was attempted with a rabbit hyperimmune serum raised against a homologous synthetic peptide derived from the HVR1 of the E2 protein, and the residual infectivity was evaluated by inoculation of HCV-seronegative chimpanzees. The source of HCV was plasma obtained from a patient (H) during the acute phase of posttransfusion non-A, non-B hepatitis, which had been titered for infectivity in chimpanzees. The anti-HVR1 antiserum induced protection against homologous HCV infection in chimpanzees, but not against the emergence of neutralization escape mutants that were found to be already present in the complex viral quasispecies of the inoculum. The finding that HVR1 can elicit protective immunity opens new perspectives for the development of effective preventive strategies. However, the identification of the most variable region of HCV as a critical neutralization domain poses a major challenge for the development of a broadly reactive vaccine against HCV.

  14. A high-fat diet increases oxidative renal injury and protein glycation in D-galactose-induced aging rats and its prevention by Korea red ginseng.

    Science.gov (United States)

    Park, Sok; Kim, Chan-Sik; Min, Jinah; Lee, Soo Hwan; Jung, Yi-Sook

    2014-01-01

    Declining renal function is commonly observed with age. Obesity induced by a high-fat diet (HFD) may reduce renal function. Korean red ginseng (KRG) has been reported to ameliorate oxidative tissue injury and have an anti-aging effect. This study was designed to investigate whether HFD would accelerate the D-galactose-induced aging process in the rat kidney and to examine the preventive effect of KRG on HFD and D-galactose-induced aging-related renal injury. When rats with D-galactose-induced aging were fed an HFD for 9 wk, enhanced oxidative DNA damage, renal cell apoptosis, protein glycation, and extracellular high mobility group box 1 protein (HMGB1), a signal of tissue damage, were observed in renal glomerular cells and tubular epithelial cells. However, treatment of rats with HFD- plus D-galactose-induced aging with KRG restored all of these renal changes. Our data suggested that a long-term HFD may enhance D-galactose-induced oxidative renal injury in rats and that this age-related renal injury could be suppressed by KRG through the repression of oxidative injury.

  15. Alzheimer's Disease Brain-Derived Amyloid-{beta}-Mediated Inhibition of LTP In Vivo Is Prevented by Immunotargeting Cellular Prion Protein.

    LENUS (Irish Health Repository)

    Barry, Andrew E

    2011-05-18

    Synthetic amyloid-β protein (Aβ) oligomers bind with high affinity to cellular prion protein (PrP(C)), but the role of this interaction in mediating the disruption of synaptic plasticity by such soluble Aβ in vitro is controversial. Here we report that intracerebroventricular injection of Aβ-containing aqueous extracts of Alzheimer\\'s disease (AD) brain robustly inhibits long-term potentiation (LTP) without significantly affecting baseline excitatory synaptic transmission in the rat hippocampus in vivo. Moreover, the disruption of LTP was abrogated by immunodepletion of Aβ. Importantly, intracerebroventricular administration of antigen-binding antibody fragment D13, directed to a putative Aβ-binding site on PrP(C), prevented the inhibition of LTP by AD brain-derived Aβ. In contrast, R1, a Fab directed to the C terminus of PrP(C), a region not implicated in binding of Aβ, did not significantly affect the Aβ-mediated inhibition of LTP. These data support the pathophysiological significance of SDS-stable Aβ dimer and the role of PrP(C) in mediating synaptic plasticity disruption by soluble Aβ.

  16. A novel mechanism of RNase L inhibition: Theiler's virus L* protein prevents 2-5A from binding to RNase L

    Science.gov (United States)

    Drappier, Melissa; Elliott, Ruth; Zhang, Rong; Weiss, Susan R.; Silverman, Robert H.

    2018-01-01

    The OAS/RNase L pathway is one of the best-characterized effector pathways of the IFN antiviral response. It inhibits the replication of many viruses and ultimately promotes apoptosis of infected cells, contributing to the control of virus spread. However, viruses have evolved a range of escape strategies that act against different steps in the pathway. Here we unraveled a novel escape strategy involving Theiler’s murine encephalomyelitis virus (TMEV) L* protein. Previously we found that L* was the first viral protein binding directly RNase L. Our current data show that L* binds the ankyrin repeats R1 and R2 of RNase L and inhibits 2’-5’ oligoadenylates (2-5A) binding to RNase L. Thereby, L* prevents dimerization and oligomerization of RNase L in response to 2-5A. Using chimeric mouse hepatitis virus (MHV) expressing TMEV L*, we showed that L* efficiently inhibits RNase L in vivo. Interestingly, those data show that L* can functionally substitute for the MHV-encoded phosphodiesterase ns2, which acts upstream of L* in the OAS/RNase L pathway, by degrading 2-5A. PMID:29652922

  17. Modulation of trabectedin (ET-743) hepatobiliary disposition by multidrug resistance-associated proteins (Mrps) may prevent hepatotoxicity

    International Nuclear Information System (INIS)

    Lee, Jin Kyung; Leslie, Elaine M.; Zamek-Gliszczynski, Maciej J.; Brouwer, Kim L.R.

    2008-01-01

    Trabectedin is a promising anticancer agent, but dose-limiting hepatotoxicity was observed during phase I/II clinical trials. Dexamethasone (DEX) has been shown to significantly reduce trabectedin-mediated hepatotoxicity. The current study was designed to assess the capability of sandwich-cultured primary rat hepatocytes (SCRH) to predict the hepato-protective effect of DEX against trabectedin-mediated cytotoxicity. The role of multidrug resistance-associated protein 2 (Mrp2; Abcc2) in trabectedin hepatic disposition also was examined. In SCRH from wild-type Wistar rats, cytotoxicity was observed after 24-h continuous exposure to trabectedin. SCRH pretreated with additional DEX (1 μM) exhibited a 2- to 3-fold decrease in toxicity at 100 nM and 1000 nM trabectedin. Unexpectedly, toxicity in SCRH from Mrp2-deficient (TR - ) compared to wild-type Wistar rats was markedly reduced. Depletion of glutathione from SCRH using buthionine sulfoximine (BSO) mitigated trabectedin toxicity associated with 100 nM and 1000 nM trabectedin. Western blot analysis demonstrated increased levels of CYP3A1/2 and Mrp2 in SCRH pretreated with DEX; interestingly, Mrp4 expression was increased in SCRH after BSO exposure. Trabectedin biliary recovery in isolated perfused livers from TR - rats was decreased by ∼ 75% compared to wild-type livers. In conclusion, SCRH represent a useful in vitro model to predict the hepatotoxicity of trabectedin observed in vivo. The protection by DEX against trabectedin-mediated cytotoxicity may be attributed, in part, to enhanced Mrp2 biliary excretion and increased metabolism by CYP3A1/2. Decreased trabectedin toxicity in SCRH from TR - rats, and in SCRH pretreated with BSO, may be due to increased basolateral excretion of trabectedin by Mrp3 and/or Mrp4

  18. CONTAMINANT ADSORPTION AND OXIDATION VIA FENTON REACTION

    Science.gov (United States)

    A ground water treatment process is proposed involving two cgemical processes: adsorption and oxidation. Adsorption of an organic compound onto granulated activated carbon (GAC) containing iron conveniently results in immobilizing and concentrating contaminants from the ground w...

  19. C-reactive protein as a risk factor for coronary heart disease: a systematic review and meta-analyses for the U.S. Preventive Services Task Force.

    Science.gov (United States)

    Buckley, David I; Fu, Rongwei; Freeman, Michele; Rogers, Kevin; Helfand, Mark

    2009-10-06

    C-reactive protein (CRP) may help to refine global risk assessment for coronary heart disease (CHD), particularly among persons who are at intermediate risk on the basis of traditional risk factors alone. To assist the U.S. Preventive Services Task Force (USPSTF) in determining whether CRP should be incorporated into guidelines for CHD risk assessment. MEDLINE search of English-language articles (1966 to November 2007), supplemented by reference lists of reviews, pertinent studies, editorials, and Web sites and by expert suggestions. Prospective cohort, case-cohort, and nested case-control studies relevant to the independent predictive ability of CRP when used in intermediate-risk persons. Included studies were reviewed according to predefined criteria, and the quality of each study was rated. The validity of the body of evidence and the net benefit or harm of using CRP for CHD risk assessment were evaluated. The combined magnitude of effect was determined by meta-analysis. The body of evidence is of good quality, consistency, and applicability. For good studies that adjusted for all Framingham risk variables, the summary estimate of relative risk for incident CHD was 1.58 (95% CI, 1.37 to 1.83) for CRP levels greater than 3.0 mg/L compared with levels less than 1.0 mg/L. Analyses from 4 large cohorts were consistent in finding evidence that including CRP improves risk stratification among initially intermediate-risk persons. C-reactive protein has desirable test characteristics, and good data exist on the prevalence of elevated CRP levels in intermediate-risk persons. Limited evidence links changes in CRP level to primary prevention of CHD events. Study methods for measuring Framingham risk variables and other covariates varied. Ethnic and racial minority populations were poorly represented in most studies, limiting generalizability. Few studies directly assessed the effect of CRP on risk reclassification in intermediate-risk persons. Strong evidence indicates

  20. Omega-3 fatty acid docosahexaenoic acid increases SorLA/LR11, a sorting protein with reduced expression in sporadic Alzheimer's disease (AD): relevance to AD prevention.

    Science.gov (United States)

    Ma, Qiu-Lan; Teter, Bruce; Ubeda, Oliver J; Morihara, Takashi; Dhoot, Dilsher; Nyby, Michael D; Tuck, Michael L; Frautschy, Sally A; Cole, Greg M

    2007-12-26

    Environmental and genetic factors, notably ApoE4, contribute to the etiology of late-onset Alzheimer's disease (LOAD). Reduced mRNA and protein for an apolipoprotein E (ApoE) receptor family member, SorLA (LR11) has been found in LOAD but not early-onset AD, suggesting that LR11 loss is not secondary to pathology. LR11 is a neuronal sorting protein that reduces amyloid precursor protein (APP) trafficking to secretases that generate beta-amyloid (Abeta). Genetic polymorphisms that reduce LR11 expression are associated with increased AD risk. However these polymorphisms account for only a fraction of cases with LR11 deficits, suggesting involvement of environmental factors. Because lipoprotein receptors are typically lipid-regulated, we postulated that LR11 is regulated by docosahexaenoic acid (DHA), an essential omega-3 fatty acid related to reduced AD risk and reduced Abeta accumulation. In this study, we report that DHA significantly increases LR11 in multiple systems, including primary rat neurons, aged non-Tg mice and an aged DHA-depleted APPsw AD mouse model. DHA also increased LR11 in a human neuronal line. In vivo elevation of LR11 was also observed with dietary fish oil in young rats with insulin resistance, a model for type II diabetes, another AD risk factor. These data argue that DHA induction of LR11 does not require DHA-depleting diets and is not age dependent. Because reduced LR11 is known to increase Abeta production and may be a significant genetic cause of LOAD, our results indicate that DHA increases in SorLA/LR11 levels may play an important role in preventing LOAD.

  1. Sardine protein diet increases plasma glucagon-like peptide-1 levels and prevents tissue oxidative stress in rats fed a high-fructose diet.

    Science.gov (United States)

    Madani, Zohra; Sener, Abdullah; Malaisse, Willy J; Dalila, Ait Yahia

    2015-11-01

    The current study investigated whether sardine protein mitigates the adverse effects of fructose on plasma glucagon‑like peptide-1 (GLP-1) and oxidative stress in rats. Rats were fed casein (C) or sardine protein (S) with or without high‑fructose (HF) for 2 months. Plasma glucose, insulin, GLP‑1, lipid and protein oxidation and antioxidant enzymes were assayed. HF rats developed obesity, hyperglycemia, hyperinsulinemia, insulin resistance and oxidative stress despite reduced energy and food intakes. High plasma creatinine and uric acid levels, in addition to albuminuria were observed in the HF groups. The S‑HF diet reduced plasma glucose, insulin, creatinine, uric acid and homeostasis model assessment‑insulin resistance index levels, however increased GLP‑1 levels compared with the C‑HF diet. Hydroperoxides were reduced in the liver, kidney, heart and muscle of S‑HF fed rats compared with C‑HF fed rats. A reduction in liver, kidney and heart carbonyls was observed in S‑HF fed rats compared with C‑HF fed rats. Reduced levels of nitric oxide (NO) were detected in the liver, kidney and heart of the S‑HF fed rats compared with C‑HF fed rats. The S diet compared with the C diet reduced levels of liver hydroperoxides, heart carbonyls and kidney NO. The S‑HF diet compared with the C‑HF diet increased the levels of liver and kidney superoxide dismutase, liver and muscle catalase, liver, heart and muscle glutathione peroxidase and liver ascorbic acid. The S diet prevented and reversed insulin resistance and oxidative stress, and may have benefits in patients with metabolic syndrome.

  2. Extensive protein hydrolyzation is indispensable to prevent IgE-mediated poultry allergen recognition in dogs and cats.

    Science.gov (United States)

    Olivry, Thierry; Bexley, Jennifer; Mougeot, Isabelle

    2017-08-17

    similar to that of the beef meat negative control. Altogether, these results suggest that an extensive-but not partial-hydrolyzation of the poultry feather extract is necessary to prevent the recognition of allergenic epitopes by poultry-specific IgE.

  3. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    OpenAIRE

    Eko Ariyanto

    2012-01-01

    A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  4. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    Directory of Open Access Journals (Sweden)

    Eko Ariyanto

    2012-02-01

    Full Text Available A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  5. Effects of gramicidin-A on the adsorption of phospholipids to the air–water interface

    Science.gov (United States)

    Biswas, Samares C.; Rananavare, Shankar B.; Hall, Stephen B.

    2012-01-01

    Prior studies suggest that the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of the lipids in pulmonary surfactant to an air–water interface by stabilizing a negatively curved rate-limiting structure that is intermediate between bilayer vesicles and the surface film. This model predicts that other peptides capable of stabilizing negative curvature should also promote lipid adsorption. Previous reports have shown that under appropriate conditions, gramicidin-A (GrA) induces dioleoyl phosphatidylcholine (DOPC), but not dimyristoyl phosphatidylcholine (DMPC), to form the negatively curved hexagonal-II (HII) phase. The studies reported here determined if GrA would produce the same effects on adsorption of DMPC and DOPC that the hydrophobic surfactant proteins have on the surfactant lipids. Small angle X-ray scattering and 31P-nuclear magnetic resonance confirmed that at the particular conditions used to study adsorption, GrA induced DOPC to form the HII phase, but DMPC remained lamellar. Measurements of surface tension showed that GrA in vesicles produced a general increase in the rate of adsorption for both phospholipids. When restricted to the interface, however, in preexisting films, GrA with DOPC, but not with DMPC, replicated the ability of the surfactant proteins to promote adsorption of vesicles containing only the lipids. The correlation between the structural and functional effects of GrA with the two phospholipids, and the similar effects on adsorption of GrA with DOPC and the hydrophobic surfactant proteins with the surfactant lipids fit with the model in which SP-B and SP-C facilitate adsorption by stabilizing a rate-limiting intermediate with negative curvature. PMID:16242116

  6. Interactions between whey proteins and kaolinite surfaces

    International Nuclear Information System (INIS)

    Barral, S.; Villa-Garcia, M.A.; Rendueles, M.; Diaz, M.

    2008-01-01

    The nature of the interactions between whey proteins and kaolinite surfaces was investigated by adsorption-desorption experiments at room temperature, performed at the isoelectric point (IEP) of the proteins and at pH 7. It was found that kaolinite is a strong adsorbent for proteins, reaching the maximum adsorption capacity at the IEP of each protein. At pH 7.0, the retention capacity decreased considerably. The adsorption isotherms showed typical Langmuir characteristics. X-ray diffraction data for the protein-kaolinite complexes showed that protein molecules were not intercalated in the mineral structure, but immobilized at the external surfaces and the edges of the kaolinite. Fourier transform IR results indicate the absence of hydrogen bonding between kaolinite surfaces and the polypeptide chain. The adsorption patterns appear to be related to electrostatic interactions, although steric effects should be also considered

  7. Interactions between whey proteins and kaolinite surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Barral, S. [Department of Chemical Engineering and Environmental Technology, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Villa-Garcia, M.A. [Department of Organic and Inorganic Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain)], E-mail: mavg@uniovi.es; Rendueles, M. [Project Management Area, University of Oviedo, Independencia 13, 33004 Oviedo (Spain); Diaz, M. [Department of Chemical Engineering and Environmental Technology, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain)

    2008-07-15

    The nature of the interactions between whey proteins and kaolinite surfaces was investigated by adsorption-desorption experiments at room temperature, performed at the isoelectric point (IEP) of the proteins and at pH 7. It was found that kaolinite is a strong adsorbent for proteins, reaching the maximum adsorption capacity at the IEP of each protein. At pH 7.0, the retention capacity decreased considerably. The adsorption isotherms showed typical Langmuir characteristics. X-ray diffraction data for the protein-kaolinite complexes showed that protein molecules were not intercalated in the mineral structure, but immobilized at the external surfaces and the edges of the kaolinite. Fourier transform IR results indicate the absence of hydrogen bonding between kaolinite surfaces and the polypeptide chain. The adsorption patterns appear to be related to electrostatic interactions, although steric effects should be also considered.

  8. Thermodynamic features of dioxins’ adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Prisciandaro, Marina [Department of Industrial and Information Engineering and of Economics, University of L’Aquila, Viale Giovanni Gronchi 18, L’Aquila 67100 (Italy); Piemonte, Vincenzo, E-mail: v.piemonte@unicampus.it [Faculty of Engineering, University Campus Biomedico of Rome, Via Alvaro del Portillo 21, Rome 00128 (Italy); Mazziotti di Celso, Giuseppe [Faculty of Bioscience, University of Teramo, Via R. Balzarini, 1, 64100 Teramo (Italy); Ronconi, Silvia [Arta Abruzzo, Department of L’Aquila, Bazzano (AQ), 67100 L’Aquila (Italy); Capocelli, Mauro [Faculty of Engineering, University Campus Biomedico of Rome, Via Alvaro del Portillo 21, Rome 00128 (Italy)

    2017-02-15

    Highlights: • We develop the P-T diagram for six PCDD. • We derive theoretical adsorption isotherms according to the Langmuir’s model. • We calculate K and w{sub max} values for several temperatures. • We estimate the adsorption heat with a good agreement with literature data. - Abstract: In this paper, the six more poisonous species among all congeners of dioxin group are taken into account, and the P-T diagram for each of them is developed. Starting from the knowledge of vapour tensions and thermodynamic parameters, the theoretical adsorption isotherms are calculated according to the Langmuir’s model. In particular, the Langmuir isotherm parameters (K and w{sub max}) have been validated through the estimation of the adsorption heat (ΔH{sub ads}), which varies in the range 20–24 kJ/mol, in agreement with literature values. This result will allow to put the thermodynamical basis for a rational design of different process units devoted to dioxins removal.

  9. Adsorptive storage of natural gas

    International Nuclear Information System (INIS)

    Yan, Song; Lang, Liu; Licheng, Ling

    2001-01-01

    The Adsorbed Natural Gas (ANG) storage technology is reviewed. The present status, theoretical limits and operational problems are discussed. Natural gas (NG) has a considerable advantage over conventional fuels both from an environmental point of view and for its natural abundance. However, as well known, it has a two fold disadvantage compared with liquid fuels: it is relatively expensive to transport from the remote areas, and its energy density (heat of combustion/volume) is low. All these will restrict its use. Compressed natural gas (CNG) may be a solution, but high pressures are needed (up to 25 MPa) for use in natural-gas fueled vehicles, and the large cost of the cylinders for storage and the high-pressure facilities necessary limit the practical use of CNG. Alternatively, adsorbed natural gas (ANG) at 3 - 4 MPa offers a very high potential for exploitation in both transport and large-scale applications. At present, research about this technology mainly focuses on: to make adsorbents with high methane adsorption capacity; to make clear the effects of heat of adsorption and the effect of impurities in natural gas on adsorption and desorption capacity. This paper provides an overview of current technology and examines the relations between fundamentals of adsorption and ANG storage. (authors)

  10. ADSORPTION OF SURFACTANT ON CLAYS

    Science.gov (United States)

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  11. Thermodynamic Properties of Chromium Adsorption by Sediments ...

    African Journals Online (AJOL)

    The adsorption of Chromium from aqueous solution using river Watari sediment as an adsorbent was modeled. The influence of initial pH, solution temperature, adsorbent and adsorbate concentrations on the adsorption efficiency was investigated using batch equilibrium assays. From the results obtained for the adsorption ...

  12. Competitive Adsorption of Chloroform and Bromoform Using ...

    African Journals Online (AJOL)

    The results obtained were checked with Freundlich adsorption isotherm model. This model expresses well adsorption of one THM species in the presence of another with R2 > 0.95. Based on the model, adsorption capacity of Calgon F200 and Norit GCN1240 were found higher for bromoform than chloroform. Calgon F200 ...

  13. Environmentally benign working pairs for adsorption refrigeration

    International Nuclear Information System (INIS)

    Cui Qun; Tao Gang; Chen Haijun; Guo Xinyue; Yao Huqing

    2005-01-01

    This paper begins from adsorption working pairs: water and ethanol were selected as refrigerants; 13x molecular sieve, silica gel, activated carbon, adsorbent NA and NB, proposed by authors, were selected as adsorbents, and the performance of adsorption working pairs in adsorption refrigeration cycle was studied. The adsorption isotherms of adsorbents (NA and NB) were obtained by high-vacuum gravimetric method. Desorption properties of adsorbents were analyzed and compared by thermal analysis method. The performance of adsorption refrigeration was studied on simulation device of adsorption refrigeration cycle. After presentation of adsorption isotherms, the thermodynamic performance for their use in adsorption refrigeration system was calculated. The results show: (1) the maximum adsorption capacity of water on adsorbent NA reaches 0.7 kg/kg, and the maximum adsorption capacity of ethanol on adsorbent NB is 0.68 kg/kg, which is three times that of ethanol on activated carbon, (2) the refrigeration capacity of NA-water working pair is 922 kJ/kg, the refrigeration capacity of NB-ethanol is 2.4 times that of activated carbon-methanol, (3) as environmental friendly and no public hazard adsorption working pair, NA-H 2 O and NB-ethanol can substitute activated carbon-methanol in adsorption refrigeration system using low-grade heat source

  14. From aggregative adsorption to surface depletion

    DEFF Research Database (Denmark)

    Rother, Gernot; Müter, Dirk; Bock, Henry

    2017-01-01

    Adsorption of a short-chain nonionic amphiphile (C6E3) at the surface of mesoporous silica glass (CPG) was studied by a combination of adsorption measurements and mesoscale simulations. Adsorption measurements covering a wide composition range of the C6E3 + water system show that no adsorption...... occurs up to the critical micelle concentration, at which a sharp increase of adsorption is observed that is attributed to ad-micelle formation at the pore walls. Intriguingly, as the concentration is increased further, the surface excess of the amphiphile begins to decrease and eventually becomes...

  15. Adsorption from solutions of non-electrolytes

    CERN Document Server

    Kipling, J J

    1965-01-01

    Adsorption from Solutions of Non-Electrolytes provides a general discussion of the subject, which has so far been given little or no attention in current textbooks of physical chemistry. A general view of the subject is particularly needed at a time when we wish to see how far it will be possible to use theories of solutions to explain the phenomena of adsorption. The book opens with an introductory chapter on the types of interface, aspects of adsorption from solution, types of adsorption, and classification of systems. This is followed by separate chapters on experimental methods, adsorption

  16. Protein Attachment on Nanodiamonds.

    Science.gov (United States)

    Lin, Chung-Lun; Lin, Cheng-Huang; Chang, Huan-Cheng; Su, Meng-Chih

    2015-07-16

    A recent advance in nanotechnology is the scale-up production of small and nonaggregated diamond nanoparticles suitable for biological applications. Using detonation nanodiamonds (NDs) with an average diameter of ∼4 nm as the adsorbents, we have studied the static attachment of three proteins (myoglobin, bovine serum albumin, and insulin) onto the nanoparticles by optical spectroscopy, mass spectrometry, and dynamic light scattering, and electrophoretic zeta potential measurements. Results show that the protein surface coverage is predominantly determined by the competition between protein-protein and protein-ND interactions, giving each protein a unique and characteristic structural configuration in its own complex. Specifically, both myoglobin and bovine serum albumin show a Langmuir-type adsorption behavior, forming 1:1 complexes at saturation, whereas insulin folds into a tightly bound multimer before adsorption. The markedly different adsorption patterns appear to be independent of the protein concentration and are closely related to the affinity of the individual proteins for the NDs. The present study provides a fundamental understanding for the use of NDs as a platform for nanomedical drug delivery.

  17. Gamma ray induced oxidative damage to human red blood cells proteins under hypotonic conditions and its prevention by natural phenolic malabaricone compounds

    International Nuclear Information System (INIS)

    Meenakshi, K.; Chattopadhyay, Subrata

    2015-01-01

    As an oxygen shuttle, Human RBCs must continue to perform the task while being exposed to a wide range of environments for each vascular circuit and to a variety of xenobiotics across its life time. The inability to synthesise new protein makes them uniquely vulnerable to oxidative stress. Antioxidants can help in protecting the RBCs from oxidative insults. Currently herbal antioxidants gained worldwide popularity as drugs and food/drug supplements for the treatment of various diseases. The present effort was aimed at formulating some natural phenolic compounds isolated from M.malabarica (mal B and mal C) to prevent the biochemical parameters which are considered as biomarkers of redox balance primarily contribute to alterations in red blood cells proteins during gamma radiation induced oxidative stress. Compared to control gamma ray treatment with hypotonic stress resulted in significant haemolysis, associated with increased MDA (3.3 fold, p<0.001) and met-haemoglobin (7.0 fold, p<0.001). The structural deformation due to membrane damage was confirmed from SEM images and Heinz body formation, while the cell permeability was evident from the K + efflux (30.4%, p<0.05) and increased intracellular Na + concentration (5.2%, p<0.05). The membrane damage, due to the reduction of the cholesterol/phospholipids ratio and depletion (p<0.001) of ATP, 2,3-DPG by 54.7% and Na + -K + ATPase activity (48.%) indicated loss of RBC functionally. Pre-treatment of the RBCs with mal B (5μM), mal C (2.5 μM) or vitamin E (50 μM) for 1 h reversed these adverse effects of gamma radiation under hypotonic conditions on all these parameters and provided significant protection against oxidative haemolysis. (author)

  18. Investigation of adsorption performance deterioration in silica gel–water adsorption refrigeration

    International Nuclear Information System (INIS)

    Wang Dechang; Zhang Jipeng; Xia Yanzhi; Han Yanpei; Wang Shuwei

    2012-01-01

    Highlights: ► Adsorption deterioration of silica gel in refrigeration systems is verified. ► Possible factors to cause such deterioration are analyzed. ► Specific surface area, silanol content and adsorption capacity are tested. ► The pollution is the primary factor to decline the adsorption capacity. ► Deteriorated samples are partly restored after being processed by acid solution. - Abstract: Silica gel acts as a key role in adsorption refrigeration systems. The adsorption deterioration must greatly impact the performance of the silica gel–water adsorption refrigeration system. In order to investigate the adsorption deterioration of silica gel, many different silica gel samples were prepared according to the application surroundings of silica gel in adsorption refrigeration systems after the likely factors to cause such deterioration were analyzed. The specific surface area, silanol content, adsorption capacity and pore size distribution of those samples were tested and the corresponding adsorption isotherms were achieved. In terms of the experimental data comparisons, it could be found that there are many factors to affect the adsorption performance of silica gel, but the pollution was the primary one to decline the adsorption capacity. In addition, the adsorption performance of the deteriorated samples after being processed by acid solution was explored in order to find the possible methods to restore its adsorption performance.

  19. Hydrogen Adsorption on Nanoporous Biocarbon

    Science.gov (United States)

    Wood, M. B.; Burress, J. W.; Lapilli, C. M.; Pfeifer, P.; Shah, P. S.; Suppes, G. J.; Dillon, A. C.; Parilla, P. A.

    2007-03-01

    As a part of the Alliance for Collaborative Research in Alternative Fuel Technology (http://all-craft.missouri.edu) we study activated carbons made from corncob, optimized for storing methane and hydrogen (H2) by physisorption at low pressure. We report here: (a) storage capacities of 73-91 g H2/kg carbon at 77 K and 47 bar, validated in three different laboratories (the 2010 DOE target is 60 g H2/kg system); (b) binding energies from H2 adsorption isotherms (c) temperature-programmed desorption data; (d) degree of graphitization of the carbon surface from Raman spectra; (e) pore structure of carbon from nitrogen and methane adsorption isotherms, and small-angle x-ray scattering. The structural analysis shows that the carbon is highly microporous and that the pore space is highly correlated (micropores do not scatter independently).

  20. Random and cooperative sequential adsorption

    Science.gov (United States)

    Evans, J. W.

    1993-10-01

    Irreversible random sequential adsorption (RSA) on lattices, and continuum "car parking" analogues, have long received attention as models for reactions on polymer chains, chemisorption on single-crystal surfaces, adsorption in colloidal systems, and solid state transformations. Cooperative generalizations of these models (CSA) are sometimes more appropriate, and can exhibit richer kinetics and spatial structure, e.g., autocatalysis and clustering. The distribution of filled or transformed sites in RSA and CSA is not described by an equilibrium Gibbs measure. This is the case even for the saturation "jammed" state of models where the lattice or space cannot fill completely. However exact analysis is often possible in one dimension, and a variety of powerful analytic methods have been developed for higher dimensional models. Here we review the detailed understanding of asymptotic kinetics, spatial correlations, percolative structure, etc., which is emerging for these far-from-equilibrium processes.

  1. Random sequential adsorption of cubes

    Science.gov (United States)

    Cieśla, Michał; Kubala, Piotr

    2018-01-01

    Random packings built of cubes are studied numerically using a random sequential adsorption algorithm. To compare the obtained results with previous reports, three different models of cube orientation sampling were used. Also, three different cube-cube intersection algorithms were tested to find the most efficient one. The study focuses on the mean saturated packing fraction as well as kinetics of packing growth. Microstructural properties of packings were analyzed using density autocorrelation function.

  2. Compound C prevents Hypoxia-Inducible Factor-1α protein stabilization by regulating the cellular oxygen availability via interaction with Mitochondrial Complex I

    Directory of Open Access Journals (Sweden)

    Hagen Thilo

    2011-04-01

    Full Text Available Abstract The transcription factor Hypoxia-Inducible Factor-1α is a master regulator of the cellular response to low oxygen concentration. Compound C, an inhibitor of AMP-activated kinase, has been reported to inhibit hypoxia dependent Hypoxia-Inducible Factor-1α activation via a mechanism that is independent of AMP-activated kinase but dependent on its interaction with the mitochondrial electron transport chain. The objective of this study is to characterize the interaction of Compound C with the mitochondrial electron transport chain and to determine the mechanism through which the drug influences the stability of the Hypoxia-Inducible Factor-1α protein. We found that Compound C functions as an inhibitor of complex I of the mitochondrial electron transport chain as demonstrated by its effect on mitochondrial respiration. It also prevents hypoxia-induced Hypoxia-Inducible Factor-1α stabilization in a dose dependent manner. In addition, Compound C does not have significant effects on reactive oxygen species production from complex I via both forward and reverse electron flux. This study provides evidence that similar to other mitochondrial electron transport chain inhibitors, Compound C regulates Hypoxia-Inducible Factor-1α stability by controlling the cellular oxygen concentration.

  3. 5-HT(2C) serotonin receptor blockade prevents tau protein hyperphosphorylation and corrects the defect in hippocampal synaptic plasticity caused by a combination of environmental stressors in mice.

    Science.gov (United States)

    Busceti, Carla Letizia; Di Pietro, Paola; Riozzi, Barbara; Traficante, Anna; Biagioni, Francesca; Nisticò, Robert; Fornai, Francesco; Battaglia, Giuseppe; Nicoletti, Ferdinando; Bruno, Valeria

    2015-09-01

    Exposure to multimodal sensory stressors is an everyday occurrence and sometimes becomes very intense, such as during rave parties or other recreational events. A growing body of evidence suggests that strong environmental stressors might cause neuronal dysfunction on their own in addition to their synergistic action with illicit drugs. Mice were exposed to a combination of physical and sensory stressors that are reminiscent of those encountered in a rave party. However, this is not a model of rave because it lacks the rewarding properties of rave. A 14-h exposure to environmental stressors caused an impairment of hippocampal long-term potentiation (LTP) and spatial memory, and an enhanced phosphorylation of tau protein in the CA1 and CA3 regions. These effects were transient and critically depended on the activation of 5-HT2C serotonin receptors, which are highly expressed in the CA1 region. Acute systemic injection of the selective 5-HT2C antagonist, RS-102,221 (2 mg/kg, i.p., 2 min prior the onset of stress), prevented tau hyperphosphorylation and also corrected the defects in hippocampal LTP and spatial memory. These findings suggest that passive exposure to a combination of physical and sensory stressors causes a reversible hippocampal dysfunction, which might compromise mechanisms of synaptic plasticity and spatial memory for a few days. Drugs that block 5-HT2C receptors might protect the hippocampus against the detrimental effect of environmental stressors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Araloside C Prevents Hypoxia/Reoxygenation-Induced Endoplasmic Reticulum Stress via Increasing Heat Shock Protein 90 in H9c2 Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Yuyang Du

    2018-04-01

    Full Text Available Araloside C (AsC is a cardioprotective triterpenoid compound that is mainly isolated from Aralia elata. This study aims to determine the effects of AsC on hypoxia-reoxygenation (H/R-induced apoptosis in H9c2 cardiomyocytes and its underlying mechanisms. Results demonstrated that pretreatment with AsC (12.5 μM for 12 h significantly suppres