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Sample records for abundant natural biopolymer

  1. Quercetin as natural stabilizing agent for bio-polymer

    NASA Astrophysics Data System (ADS)

    Morici, Elisabetta; Arrigo, Rossella; Dintcheva, Nadka Tzankova

    2014-05-01

    The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. The quercetin is able to slow down the photo-degradation rate of all bio-polymeric films investigated in similar way to the synthetic stabilizer.

  2. Quercetin as natural stabilizing agent for bio-polymer

    SciTech Connect

    Morici, Elisabetta; Arrigo, Rossella; Dintcheva, Nadka Tzankova

    2014-05-15

    The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. The quercetin is able to slow down the photo-degradation rate of all bio-polymeric films investigated in similar way to the synthetic stabilizer.

  3. Carbohydrate nanotechnology: hierarchical assembly using nature's other information carrying biopolymers.

    PubMed

    Han, Xu; Zheng, Yeting; Munro, Catherine J; Ji, Yiwen; Braunschweig, Adam B

    2015-08-01

    Despite their central role in directing some of the most complex biological processes, carbohydrates--nature's other information carrying biopolymer--have been largely ignored as building blocks for synthetic hierarchical assemblies. The non-stoichiometric binding and astronomical diversity characteristic of carbohydrates could lead to tantalizingly complex assembly algorithms, but these attributes simultaneously increase the difficulty of preparing carbohydrate assemblies and anticipating their behavior. Convergences in biotechnology, nanotechnology, polymer chemistry, surface science, and supramolecular chemistry have led to many recent important breakthroughs in glycan microarrays and synthetic carbohydrate receptors, where the idiosyncrasies of carbohydrate structure and binding are increasingly considered. We hope to inspire more researchers to consider carbohydrate structure, diversity, and binding as attractive tools for constructing synthetic hierarchical assemblies.

  4. Helium isotopic abundance variation in nature

    SciTech Connect

    Holden, N.E.

    1993-08-01

    The isotopic abundance of helium in nature has been reviewed. This atomic weight value is based on the value of helium in the atmosphere, which is invariant around the world and up to a distance of 100,000 feet. Helium does vary in natural gas, volcanic rocks and gases, ocean floor sediments, waters of various types and in radioactive minerals and ores due to {alpha} particle decay of radioactive nuclides.

  5. Will Abundant Natural Gas Solve Climate Change?

    NASA Astrophysics Data System (ADS)

    McJeon, H. C.; Edmonds, J.; Bauer, N.; Leon, C.; Fisher, B.; Flannery, B.; Hilaire, J.; Krey, V.; Marangoni, G.; Mi, R.; Riahi, K.; Rogner, H.; Tavoni, M.

    2015-12-01

    The rapid deployment of hydraulic fracturing and horizontal drilling technologies enabled the production of previously uneconomic shale gas resources in North America. Global deployment of these advanced gas production technologies could bring large influx of economically competitive unconventional gas resources to the energy system. It has been hoped that abundant natural gas substituting for coal could reduce carbon dioxide (CO2) emissions, which in turn could reduce climate forcing. Other researchers countered that the non-CO2 greenhouse gas (GHG) emissions associated with shale gas production make its lifecycle emissions higher than those of coal. In this study, we employ five state-of-the-art integrated assessment models (IAMs) of energy-economy-climate systems to assess the full impact of abundant gas on climate change. The models show large additional natural gas consumption up to +170% by 2050. The impact on CO2 emissions, however, is found to be much smaller (from -2% to +11%), and a majority of the models reported a small increase in climate forcing (from -0.3% to +7%) associated with the increased use of abundant gas. Our results show that while globally abundant gas may substantially change the future energy market equilibrium, it will not significantly mitigate climate change on its own in the absence of climate policies.

  6. Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers.

    PubMed

    Bachand, George D; Spoerke, Erik D; Stevens, Mark J

    2015-06-01

    For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. One intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are one of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.

  7. Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers

    SciTech Connect

    Bachand, George D.; Stevens, Mark J.; Spoerke, Erik David

    2015-04-09

    For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. In addition, one intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are one of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.

  8. Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers

    DOE PAGES

    Bachand, George D.; Stevens, Mark J.; Spoerke, Erik David

    2015-04-09

    For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. In addition, one intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are onemore » of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.« less

  9. Soft Tissue Regeneration under the Effect of Wound Coating Based on Chitosan (Natural Biopolymer).

    PubMed

    Gladkova, E V; Babushkina, I V; Norkin, I A; Mamonova, I A; Puchin'yan, D M; Konyuchenko, E A

    2016-03-01

    We developed wound coating based on natural biopolymer chitosan with additional components (ceruloplasmin, L-asparaginic acid, and glycerol). Experiments on albino male rats demonstrated its regeneratory, antioxidant, and antibacterial effects on wounds involving all layers of the skin. Due to chemical composition and buffer component, the biodegraded wound coating optimizes all phases of the wound process, accelerates by 22-28% the reparative regeneration, and leads to anatomic and functional restoration of injured sites. High absorption capacity recommends its use in the treatment of wounds with profuse exudation.

  10. Natural Minerals Coated by Biopolymer Chitosan: Synthesis, Physicochemical, and Adsorption Properties

    NASA Astrophysics Data System (ADS)

    Budnyak, T. M.; Yanovska, E. S.; Kichkiruk, O. Yu.; Sternik, D.; Tertykh, V. A.

    2016-11-01

    Natural minerals are widely used in treatment technologies as mineral fertilizer, food additive in animal husbandry, and cosmetics because they combine valuable ion-exchanging and adsorption properties together with unique physicochemical and medical properties. Saponite (saponite clay) of the Ukrainian Podillya refers to the class of bentonites, a subclass of layered magnesium silicate montmorillonite. Clinoptilolits are aluminosilicates with carcase structure. In our work, we have coated biopolymer chitosan on the surfaces of natural minerals of Ukrainian origin — Podilsky saponite and Sokyrnitsky clinoptilolite. Chitosan mineral composites have been obtained by crosslinking of adsorbed biopolymer on saponite and clinoptilolite surface with glutaraldehyde. The obtained composites have been characterized by the physicochemical methods such as thermogravimetric/differential thermal analyses (DTA, DTG, TG), differential scanning calorimetry, mass analysis, nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between the silica and chitosan molecule. The adsorption of microquantities of cations Cu(II), Zn(II), Fe(III), Cd(II), and Pb(II) by the obtained composites and the initial natural minerals has been studied from aqueous solutions. The sorption capacities and kinetic adsorption characteristics of the adsorbents were estimated. It was found that the obtained results have shown that the ability of chitosan to coordinate heavy metal ions Zn(II), Cu(II), Cd(II), and Fe(III) is less or equal to the ability to retain ions of these metals in the pores of minerals without forming chemical bonds.

  11. Natural Minerals Coated by Biopolymer Chitosan: Synthesis, Physicochemical, and Adsorption Properties.

    PubMed

    Budnyak, T M; Yanovska, E S; Kichkiruk, O Yu; Sternik, D; Tertykh, V A

    2016-12-01

    Natural minerals are widely used in treatment technologies as mineral fertilizer, food additive in animal husbandry, and cosmetics because they combine valuable ion-exchanging and adsorption properties together with unique physicochemical and medical properties. Saponite (saponite clay) of the Ukrainian Podillya refers to the class of bentonites, a subclass of layered magnesium silicate montmorillonite. Clinoptilolits are aluminosilicates with carcase structure. In our work, we have coated biopolymer chitosan on the surfaces of natural minerals of Ukrainian origin - Podilsky saponite and Sokyrnitsky clinoptilolite. Chitosan mineral composites have been obtained by crosslinking of adsorbed biopolymer on saponite and clinoptilolite surface with glutaraldehyde. The obtained composites have been characterized by the physicochemical methods such as thermogravimetric/differential thermal analyses (DTA, DTG, TG), differential scanning calorimetry, mass analysis, nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between the silica and chitosan molecule. The adsorption of microquantities of cations Cu(II), Zn(II), Fe(III), Cd(II), and Pb(II) by the obtained composites and the initial natural minerals has been studied from aqueous solutions. The sorption capacities and kinetic adsorption characteristics of the adsorbents were estimated. It was found that the obtained results have shown that the ability of chitosan to coordinate heavy metal ions Zn(II), Cu(II), Cd(II), and Fe(III) is less or equal to the ability to retain ions of these metals in the pores of minerals without forming chemical bonds.

  12. Natural additives and agricultural wastes in biopolymer formulations for food packaging

    NASA Astrophysics Data System (ADS)

    Valdés, Arantzazu; Mellinas, Ana Cristina; Ramos, Marina; Garrigós, María Carmen; Jiménez, Alfonso

    2014-02-01

    The main directions in food packaging research are targeted towards improvements in food quality and food safety. For this purpose, food packaging providing longer product shelf-life, as well as the monitoring of safety and quality based upon international standards, is desirable. New active packaging strategies represent a key area of development in new multifunctional materials where the use of natural additives and/or agricultural wastes is getting increasing interest. The development of new materials, and particularly innovative biopolymer formulations, can help to address these requirements and also with other packaging functions such as: food protection and preservation, marketing and smart communication to consumers. The use of biocomposites for active food packaging is one of the most studied approaches in the last years on materials in contact with food. Applications of these innovative biocomposites could help to provide new food packaging materials with improved mechanical, barrier, antioxidant and antimicrobial properties. From the food industry standpoint, concerns such as the safety and risk associated with these new additives, migration properties and possible human ingestion and regulations need to be considered. The latest innovations in the use of these innovative formulations to obtain biocomposites are reported in this review. Legislative issues related to the use of natural additives and agricultural wastes in food packaging systems are also discussed.

  13. Natural additives and agricultural wastes in biopolymer formulations for food packaging

    PubMed Central

    Valdés, Arantzazu; Mellinas, Ana Cristina; Ramos, Marina; Garrigós, María Carmen; Jiménez, Alfonso

    2014-01-01

    The main directions in food packaging research are targeted toward improvements in food quality and food safety. For this purpose, food packaging providing longer product shelf-life, as well as the monitoring of safety and quality based upon international standards, is desirable. New active packaging strategies represent a key area of development in new multifunctional materials where the use of natural additives and/or agricultural wastes is getting increasing interest. The development of new materials, and particularly innovative biopolymer formulations, can help to address these requirements and also with other packaging functions such as: food protection and preservation, marketing and smart communication to consumers. The use of biocomposites for active food packaging is one of the most studied approaches in the last years on materials in contact with food. Applications of these innovative biocomposites could help to provide new food packaging materials with improved mechanical, barrier, antioxidant, and antimicrobial properties. From the food industry standpoint, concerns such as the safety and risk associated with these new additives, migration properties and possible human ingestion and regulations need to be considered. The latest innovations in the use of these innovative formulations to obtain biocomposites are reported in this review. Legislative issues related to the use of natural additives and agricultural wastes in food packaging systems are also discussed. PMID:24790975

  14. Natural additives and agricultural wastes in biopolymer formulations for food packaging.

    PubMed

    Valdés, Arantzazu; Mellinas, Ana Cristina; Ramos, Marina; Garrigós, María Carmen; Jiménez, Alfonso

    2014-01-01

    The main directions in food packaging research are targeted toward improvements in food quality and food safety. For this purpose, food packaging providing longer product shelf-life, as well as the monitoring of safety and quality based upon international standards, is desirable. New active packaging strategies represent a key area of development in new multifunctional materials where the use of natural additives and/or agricultural wastes is getting increasing interest. The development of new materials, and particularly innovative biopolymer formulations, can help to address these requirements and also with other packaging functions such as: food protection and preservation, marketing and smart communication to consumers. The use of biocomposites for active food packaging is one of the most studied approaches in the last years on materials in contact with food. Applications of these innovative biocomposites could help to provide new food packaging materials with improved mechanical, barrier, antioxidant, and antimicrobial properties. From the food industry standpoint, concerns such as the safety and risk associated with these new additives, migration properties and possible human ingestion and regulations need to be considered. The latest innovations in the use of these innovative formulations to obtain biocomposites are reported in this review. Legislative issues related to the use of natural additives and agricultural wastes in food packaging systems are also discussed.

  15. Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

    SciTech Connect

    Kuntanoo, K.; Promkotra, S.; Kaewkannetra, P.

    2015-03-30

    A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (T{sub m}) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.

  16. Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

    NASA Astrophysics Data System (ADS)

    Kuntanoo, K.; Promkotra, S.; Kaewkannetra, P.

    2015-03-01

    A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (Tm) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.

  17. A Targeted Nanoprobe Based on Carbon Nanotubes-Natural Biopolymer Chitosan Composites

    PubMed Central

    Wu, Baoyan; Zhao, Na

    2016-01-01

    A novel targeting theranostic nanoprobe based on single-walled carbon nanotubes (SWCNTs)-natural biopolymer chitosan composites was developed for cancer cell targeting imaging and fluorescence imaging-guided photodynamic therapy. First, chitosan was respectively conjugated with a tumor-homing molecule folic acid, or a photosensitizing drug pyropheophorbide a using a water-soluble carbodiimide coupling chemistry. Chitosan was fluorescently labeled by fluorescein isothiocyanate via the covalently linkage of the isothiocyanate group with the amino group. Second, SWCNTs were sonicated in the functional chitosan aqueous solution for 6 h at room temperature in order to obtain the nanoprobe (PPa/FITC-SWCNT-FA). The as-prepared nanoprobe has been characterized with transmission electron microscope, confocal microscopy, and cell cytotoxicity tests. Chitosan was decorated onto SWCNTs resulting in the water-dispersible PPa/FITC-SWCNT-FA, and can be selectively transported inside folate receptor-positive tumor cell with good targeting imaging. PPa/FITC-SWCNT-FA exhibited low dark toxicity about 7%–13%, and high phototoxicity about 60%–74% against HeLa cells upon a 635 nm laser irradiation, indicating satisfying biocompatibility and antitumor activity. These results suggest the study could offer a feasible alternative to presently available nanoparticle-based theranostic agents. PMID:28335344

  18. Remediation studies of trace metals in natural and treated water using surface modified biopolymer nanofibers

    NASA Astrophysics Data System (ADS)

    Musyoka, Stephen Makali; Ngila, Jane Catherine; Mamba, Bhekie B.

    In this study, remediation results of trace metals in natural water and treated water using three functionalized nanofiber mats of cellulose and chitosan are reported. The nanofiber materials, packed in mini-columns, were employed for the remediation of five toxic trace metals (Cd, Pb, Cu, Cr and Ni) from natural water samples. Trace metals in real water samples were undetectable as the concentrations were lower than the instrument’s detection limits of 0.27 × 10-3 (Cd) and 4.2 × 10-2 (Pb) μg mL-1, respectively. However, after percolation through the functionalised biosorbents in cartridges, detectability of the metal ions was enhanced. The starting volume of the natural water sample was 100 mL, which was passed through a column containing the nanofibers sorbent and the retained metals eluted with 5 mL of 2.0 M nitric acid. The eluate was analyzed for metals concentrations. An enrichment factor of 20 for the metals was realized as a result of the pre-concentration procedure applied to handle the determination of the metals at trace levels. The order of remediation of the studied metals using the nanofibers was as follows: chitosan/PAM-g-furan-2,5-dione < cellulose-g-furan-2,5-dione < cellulose-g-oxolane-2,5-dione. The modified biopolymer nanofibers were able to adsorb trace metals from the river water and treated water, thereby confirming their capability of water purification. These materials are proposed as useful tools and innovative approach for improving the quality of drinking for those consumers in small scale households.

  19. Electromechanical actuation with controllable motion based on a single-walled carbon nanotube and natural biopolymer composite.

    PubMed

    Hu, Ying; Chen, Wei; Lu, Luhua; Liu, Jinghai; Chang, Chunrui

    2010-06-22

    This paper reports novel electromechanical behavior for a natural biopolymer film due to the incorporation of a conductive carbon nanotube network. Through simple solution blending and casting, high weight fraction single-walled carbon nanotube-chitosan composite films were fabricated and exhibited electromechanical actuation properties with motion controlled by low alternating voltage stimuli in atmospheric conditions. Of particular interest and importance is that the displacement output imitated perfectly the electrical input signal in terms of frequency (<10 Hz) and waveform. Operational reliability was confirmed by stable vibration testing in air for more than 3000 cycles. Proposed electrothermal mechanism considering the alternating current-induced periodic thermal expansion and contraction of the composite film was discussed. The unique actuation performance of the carbon nanotube-biopolymer composite, coupled with ease of fabrication, low driven voltage, tunable vibration, reliable operation, and good biocompatibility, shows great possibility for implementation of dry actuators in artificial muscle and microsystems for biomimetic applications.

  20. Formation and stabilization of nanoemulsion-based vitamin E delivery systems using natural biopolymers: Whey protein isolate and gum arabic.

    PubMed

    Ozturk, Bengu; Argin, Sanem; Ozilgen, Mustafa; McClements, David Julian

    2015-12-01

    Natural biopolymers, whey protein isolate (WPI) and gum arabic (GA), were used to fabricate emulsion-based delivery systems for vitamin E-acetate. Stable delivery systems could be formed when vitamin E-acetate was mixed with sufficient orange oil prior to high pressure homogenization. WPI (d32=0.11 μm, 1% emulsifier) was better than GA (d32=0.38 μm, 10% emulsifier) at producing small droplets at low emulsifier concentrations. However, WPI-stabilized nanoemulsions were unstable to flocculation near the protein isoelectric point (pH 5.0), at high ionic strength (>100mM), and at elevated temperatures (>60 °C), whereas GA-stabilized emulsions were stable. This difference was attributed to differences in emulsifier stabilization mechanisms: WPI by electrostatic repulsion; GA by steric repulsion. These results provide useful information about the emulsifying and stabilizing capacities of natural biopolymers for forming food-grade vitamin-enriched delivery systems.

  1. Biopolymers and supramolecular polymers as biomaterials for biomedical applications

    PubMed Central

    Freeman, Ronit; Boekhoven, Job; Dickerson, Matthew B.; Naik, Rajesh R.

    2015-01-01

    Protein- and peptide-based structural biopolymers are abundant building blocks of biological systems. Either in their natural forms, such as collagen, silk or fibronectin, or as related synthetic materials they can be used in various technologies. An emerging area is that of biomimetic materials inspired by protein-based biopolymers, which are made up of small molecules rather than macromolecules and can therefore be described as supramolecular polymers. These materials are very useful in biomedical applications because of their ability to imitate the extracellular matrix both in architecture and their capacity to signal cells. This article describes important features of the natural extracellular matrix and highlight how these features are being incorporated into biomaterials composed of biopolymers and supramolecular polymers. We particularly focus on the structures, properties, and functions of collagen, fibronectin, silk, and the supramolecular polymers inspired by them as biomaterials for regenerative medicine. PMID:26989295

  2. The new face of isotopic NMR at natural abundance.

    PubMed

    Jézéquel, Tangi; Joubert, Valentin; Giraudeau, Patrick; Remaud, Gérald S; Akoka, Serge

    2017-02-01

    The most widely used method for isotope analysis at natural abundance is isotope ratio monitoring by Mass Spectrometry (irm-MS) which provides bulk isotopic composition in (2) H, (13) C, (15) N, (18) O or (34) S. However, in the 1980s, the direct access to Site-specific Natural Isotope Fractionation by Nuclear Magnetic Resonance (SNIF-NMR(TM) ) was immediately recognized as a powerful technique to authenticate the origin of natural or synthetic products. The initial - and still most popular - application consisted in detecting the chaptalization of wines by irm-(2) H NMR. The approach has been extended to a wide range of methodologies over the last decade, paving the way to a wide range of applications, not only in the field of authentication but also to study metabolism. In particular, the emerging irm-(13) C NMR approach delivers direct access to position-specific (13) C isotope content at natural abundance. After highlighting the application scope of irm-NMR ((2) H and (13) C), this article describes the major improvements which made possible to reach the required accuracy of 1‰ (0.1%) in irm-(13) C NMR. The last part of the manuscript summarizes the different steps to perform isotope analysis as a function of the sample properties (concentration, peak overlap) and the kind of targeted isotopic information (authentication, affiliation). Copyright © 2016 John Wiley & Sons, Ltd.

  3. Chlorine-36 abundance in natural and synthetic perchlorate

    SciTech Connect

    Heikoop, Jeffrey M; Dale, M; Sturchio, Neil C; Caffee, M; Belosa, A D; Heraty, Jr., L J; Bohike, J K; Hatzinger, P B; Jackson, W A; Gu, B

    2009-01-01

    Perchlorate (ClO{sub 4}{sup -}) is ubiquitous in the environment. It occurs naturally as a product of atmospheric photochemical reactions, and is synthesized for military, aerospace, and industrial applications. Nitrate-enriched soils of the Atacama Desert (Chile) contain high concentrations of natural ClO{sub 4}{sup -}; nitrate produced from these soils has been exported worldwide since the mid-1800's for use in agriculture. The widespread introduction of synthetic and agricultural ClO{sub 4}{sup -} into the environment has complicated attempts to understand the geochemical cycle of ClO{sub 4}{sup -}. Natural ClO{sub 4}{sup -} samples from the southwestern United States have relatively high {sup 36}Cl abundances ({sup 36}Cl/Cl = 3,100 x 10{sup -15} to 28,800 x 10{sup -15}), compared with samples of synthetic ({sup 36}Cl/Cl = 0.0 x 10{sup -15} to 40 x 10{sup -15}) and Atacama Desert ({sup 36}Cl/Cl = 0.9 x 10{sup -15} to 590 x 10{sup -15}) ClO{sub 4}{sup -}. These data give a lower limit for the initial {sup 36}Cl abundance of natural ClO{sub 4}{sup -} and provide temporal and other constraints on its geochemical cycle.

  4. Paper Thermoelectrics: Merging Nanotechnology with Naturally Abundant Fibrous Material.

    PubMed

    Sun, Chengjun; Goharpey, Amir Hossein; Rai, Ayush; Zhang, Teng; Ko, Dong-Kyun

    2016-08-31

    The development of paper-based sensors, antennas, and energy-harvesting devices can transform the way electronic devices are manufactured and used. Herein we describe an approach to fabricate paper thermoelectric generators for the first time by directly impregnating naturally abundant cellulose materials with p- or n-type colloidal semiconductor quantum dots. We investigate Seebeck coefficients and electrical conductivities as a function of temperature between 300 and 400 K as well as in-plane thermal conductivities using Angstrom's method. We further demonstrate equipment-free fabrication of flexible thermoelectric modules using p- and n-type paper strips. Leveraged by paper's inherently low thermal conductivity and high flexibility, these paper modules have the potential to efficiently utilize heat available in natural and man-made environments by maximizing the thermal contact to heat sources of arbitrary geometry.

  5. ¹³C NMR metabolomics: applications at natural abundance.

    PubMed

    Clendinen, Chaevien S; Lee-McMullen, Brittany; Williams, Caroline M; Stupp, Gregory S; Vandenborne, Krista; Hahn, Daniel A; Walter, Glenn A; Edison, Arthur S

    2014-09-16

    (13)C NMR has many advantages for a metabolomics study, including a large spectral dispersion, narrow singlets at natural abundance, and a direct measure of the backbone structures of metabolites. However, it has not had widespread use because of its relatively low sensitivity compounded by low natural abundance. Here we demonstrate the utility of high-quality (13)C NMR spectra obtained using a custom (13)C-optimized probe on metabolomic mixtures. A workflow was developed to use statistical correlations between replicate 1D (13)C and (1)H spectra, leading to composite spin systems that can be used to search publicly available databases for compound identification. This was developed using synthetic mixtures and then applied to two biological samples, Drosophila melanogaster extracts and mouse serum. Using the synthetic mixtures we were able to obtain useful (13)C-(13)C statistical correlations from metabolites with as little as 60 nmol of material. The lower limit of (13)C NMR detection under our experimental conditions is approximately 40 nmol, slightly lower than the requirement for statistical analysis. The (13)C and (1)H data together led to 15 matches in the database compared to just 7 using (1)H alone, and the (13)C correlated peak lists had far fewer false positives than the (1)H generated lists. In addition, the (13)C 1D data provided improved metabolite identification and separation of biologically distinct groups using multivariate statistical analysis in the D. melanogaster extracts and mouse serum.

  6. 13C NMR Metabolomics: Applications at Natural Abundance

    PubMed Central

    2015-01-01

    13C NMR has many advantages for a metabolomics study, including a large spectral dispersion, narrow singlets at natural abundance, and a direct measure of the backbone structures of metabolites. However, it has not had widespread use because of its relatively low sensitivity compounded by low natural abundance. Here we demonstrate the utility of high-quality 13C NMR spectra obtained using a custom 13C-optimized probe on metabolomic mixtures. A workflow was developed to use statistical correlations between replicate 1D 13C and 1H spectra, leading to composite spin systems that can be used to search publicly available databases for compound identification. This was developed using synthetic mixtures and then applied to two biological samples, Drosophila melanogaster extracts and mouse serum. Using the synthetic mixtures we were able to obtain useful 13C–13C statistical correlations from metabolites with as little as 60 nmol of material. The lower limit of 13C NMR detection under our experimental conditions is approximately 40 nmol, slightly lower than the requirement for statistical analysis. The 13C and 1H data together led to 15 matches in the database compared to just 7 using 1H alone, and the 13C correlated peak lists had far fewer false positives than the 1H generated lists. In addition, the 13C 1D data provided improved metabolite identification and separation of biologically distinct groups using multivariate statistical analysis in the D. melanogaster extracts and mouse serum. PMID:25140385

  7. Natural emulsifiers - Biosurfactants, phospholipids, biopolymers, and colloidal particles: Molecular and physicochemical basis of functional performance.

    PubMed

    McClements, David Julian; Gumus, Cansu Ekin

    2016-08-01

    There is increasing consumer pressure for commercial products that are more natural, sustainable, and environmentally friendly, including foods, cosmetics, detergents, and personal care products. Industry has responded by trying to identify natural alternatives to synthetic functional ingredients within these products. The focus of this review article is on the replacement of synthetic surfactants with natural emulsifiers, such as amphiphilic proteins, polysaccharides, biosurfactants, phospholipids, and bioparticles. In particular, the physicochemical basis of emulsion formation and stabilization by natural emulsifiers is discussed, and the benefits and limitations of different natural emulsifiers are compared. Surface-active polysaccharides typically have to be used at relatively high levels to produce small droplets, but the droplets formed are highly resistant to environmental changes. Conversely, surface-active proteins are typically utilized at low levels, but the droplets formed are highly sensitive to changes in pH, ionic strength, and temperature. Certain phospholipids are capable of producing small oil droplets during homogenization, but again the droplets formed are highly sensitive to changes in environmental conditions. Biosurfactants (saponins) can be utilized at low levels to form fine oil droplets that remain stable over a range of environmental conditions. Some nature-derived nanoparticles (e.g., cellulose, chitosan, and starch) are effective at stabilizing emulsions containing relatively large oil droplets. Future research is encouraged to identify, isolate, purify, and characterize new types of natural emulsifier, and to test their efficacy in food, cosmetic, detergent, personal care, and other products.

  8. Biopolymers as a flexible resource for nanochemistry.

    PubMed

    Schnepp, Zoe

    2013-01-21

    Biomass is an abundant source of chemically diverse macromolecules, including polysaccharides, polypeptides, and polyaromatics. Many of these biological polymers (biopolymers) are highly evolved for specific functions through optimized chain length, functionalization, and monomer sequence. As biopolymers are a chemical resource, much current effort is focused on the breakdown of these molecules into fuels or platform chemicals. However there is growing interest in using biopolymers directly to create functional materials. This Minireview uses recent examples to show how biopolymers are providing new directions in the synthesis of nanostructured materials.

  9. Diversity and abundance of phosphonate biosynthetic genes in nature

    PubMed Central

    Yu, Xiaomin; Doroghazi, James R.; Janga, Sarath C.; Zhang, Jun Kai; Circello, Benjamin; Griffin, Benjamin M.; Labeda, David P.; Metcalf, William W.

    2013-01-01

    Phosphonates, molecules containing direct carbon–phosphorus bonds, compose a structurally diverse class of natural products with interesting and useful biological properties. Although their synthesis in protozoa was discovered more than 50 y ago, the extent and diversity of phosphonate production in nature remains poorly characterized. The rearrangement of phosphoenolpyruvate (PEP) to phosphonopyruvate, catalyzed by the enzyme PEP mutase (PepM), is shared by the vast majority of known phosphonate biosynthetic pathways. Thus, the pepM gene can be used as a molecular marker to examine the occurrence and abundance of phosphonate-producing organisms. Based on the presence of this gene, phosphonate biosynthesis is common in microbes, with ∼5% of sequenced bacterial genomes and 7% of genome equivalents in metagenomic datasets carrying pepM homologs. Similarly, we detected the pepM gene in ∼5% of random actinomycete isolates. The pepM-containing gene neighborhoods from 25 of these isolates were cloned, sequenced, and compared with those found in sequenced genomes. PEP mutase sequence conservation is strongly correlated with conservation of other nearby genes, suggesting that the diversity of phosphonate biosynthetic pathways can be predicted by examining PEP mutase diversity. We used this approach to estimate the range of phosphonate biosynthetic pathways in nature, revealing dozens of discrete groups in pepM amplicons from local soils, whereas hundreds were observed in metagenomic datasets. Collectively, our analyses show that phosphonate biosynthesis is both diverse and relatively common in nature, suggesting that the role of phosphonate molecules in the biosphere may be more important than is often recognized. PMID:24297932

  10. Biopolymer nano-particles and natural nano-carriers for nano-encapsulation of phenolic compounds.

    PubMed

    Faridi Esfanjani, Afshin; Jafari, Seid Mahdi

    2016-10-01

    Phenolic compounds are major micronutrients in our diet,(1) and evidence for their role in the prevention of degenerative diseases such as cancer, inflammation and neurodegenerative diseases is emerging. The easily destruction against environment stresses and low bioavailability of phenolics are main limitations of their application. Therefore, nano-encapsulated phenolics as a fine delivery system can solve their restrictions. Polymeric nanoparticles and natural nano-carriers are one of the most effective and industrial techniques which can be used for protection and delivery of phenolics. In this review, preparation, application and characterization of polymeric based nano-capsules and natural nano-carriers for phenolics have been considered and discussed including polymeric nanoparticles, polymeric complex nanoparticles, cyclodextrins, nano-caseins, nanocrystals, electrospun nano-fibers, electro-sprayed nano-particles, and nano-spray dried particles. Our main goal was to cover the relevant recent studies in the past few years. Although a number of different types of polymeric and natural based nano-scale delivery systems have been developed, there are relatively poor quantitative understanding of their in vivo absorption, permeation and release. Also, performing toxicity experiments, residual solvent analysis and studying their biological fate during digestion, absorption, and excretion of polymeric nanoparticle and natural nano-carriers containing phenolics should be considered in future researches. In addition, future investigations could focus on application of phenolic nano-scale delivery systems in pharmaceuticals and functional foods.

  11. Carbon Microfibers with Hierarchical Porous Structure from Electrospun Fiber-Like Natural Biopolymer

    NASA Astrophysics Data System (ADS)

    Liang, Yeru; Wu, Dingcai; Fu, Ruowen

    2013-01-01

    Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor.

  12. Carbon Microfibers with Hierarchical Porous Structure from Electrospun Fiber-Like Natural Biopolymer

    PubMed Central

    Liang, Yeru; Wu, Dingcai; Fu, Ruowen

    2013-01-01

    Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor. PMID:23350027

  13. Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production.

    PubMed

    Simon-Colin, Christelle; Gueguen, Yannick; Bachere, Evelyne; Kouzayha, Achraf; Saulnier, Denis; Gayet, Nicolas; Guezennec, Jean

    2015-06-11

    Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with two marine bacterial exopolymers as alternative treatment agents. In field studies, the combination treatment resulted in a significant reduction in graft failures vs. untreated controls. The combination of tachyplesin (73 mg/L) with two bacterial exopolysaccharides (0.5% w/w) acting as filming agents, reduces graft-associated bacterial contamination. The survival data were similar to that reported for antibiotic treatments. These data suggest that non-antibiotic treatments of pearl oysters may provide an effective means of improving oyster survival following grafting procedures.

  14. Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production

    PubMed Central

    Simon-Colin, Christelle; Gueguen, Yannick; Bachere, Evelyne; Kouzayha, Achraf; Saulnier, Denis; Gayet, Nicolas; Guezennec, Jean

    2015-01-01

    Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with two marine bacterial exopolymers as alternative treatment agents. In field studies, the combination treatment resulted in a significant reduction in graft failures vs. untreated controls. The combination of tachyplesin (73 mg/L) with two bacterial exopolysaccharides (0.5% w/w) acting as filming agents, reduces graft-associated bacterial contamination. The survival data were similar to that reported for antibiotic treatments. These data suggest that non-antibiotic treatments of pearl oysters may provide an effective means of improving oyster survival following grafting procedures. PMID:26110895

  15. Antimicrobial assays of natural extracts and their inhibitory effect against Listeria innocua and fish spoilage bacteria, after incorporation into biopolymer edible films.

    PubMed

    Iturriaga, L; Olabarrieta, I; de Marañón, I Martínez

    2012-08-01

    The antimicrobial activity of twelve natural extracts was tested against two fish spoilage bacteria (Pseudomonas fluorescens and Aeromonas hydrophila/caviae) and Listeria innocua, in order to assess their potential utilization in the preservation and safety of minimally processed fish products. After a screening of the active extracts by agar diffusion and vapour diffusion methods, oregano and thyme essential oils and citrus extract were selected. The minimum inhibitory concentration (MIC) of the selected extracts was determined by disc diffusion method against target bacteria and at two temperatures: bacteria's optimal growth temperature (30 °C or 37 °C) and refrigeration temperature (4 °C). Due to its better solubility, lack of odour and greater inhibitory effect obtained against L. innocua at refrigerated temperature, citrus extract was selected and incorporated at 1% (v/v) into different biopolymer film forming solutions (gelatin, methyl cellulose and their blend 50:50 w/w). The antimicrobial activity of the developed films was then evaluated, just after preparation of the films and after one month of storage at 43±3% relative humidity and 24±3 °C. Regardless of the biopolymer matrix, all the developed films showed antimicrobial activity against the target bacteria. The most sensitive bacterium towards active films was L. innocua while P. fluorescens appeared as the most resistant one, in accordance with the previously performed antimicrobial tests for pure extracts. The differences in activity of the films between the tested two temperatures were not significant except for L. innocua, for which three times higher inhibition diameters were observed at refrigerated temperature. The inhibitory effectiveness of the films against the tested strains was maintained regardless of the biopolymer matrix for at least one month. Therefore, these edible films show potential for their future use in fresh fish fillets preservation.

  16. Diversity and abundance of phosphonate biosynthetic genes in nature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphonates, molecules containing direct C-P bonds, comprise a structurally diverse class of natural products with interesting and useful biological properties. Although their synthesis in protozoa was discovered more than fifty years ago, the extent and diversity of phosphonate production in natur...

  17. Nanoparticles based on naturally-occurring biopolymers as versatile delivery platforms for delicate bioactive molecules: an application for ocular gene silencing.

    PubMed

    Parraga, Jenny E; Zorzi, Giovanni K; Diebold, Yolanda; Seijo, Begoña; Sanchez, Alejandro

    2014-12-30

    Nanoparticles based on naturally-occurring biopolymers, most of them endogenous macromolecules, were designed as a versatile generation of delivery platforms for delicate bioactive molecules. The design of these nanosystems was specifically based on our recent finding about the ability of endogenous polyamine spermine (SPM) to interact with anionic biopolymers (ABs) generating ionically cross-linked nanosystems. The initial first generation of these delivery platforms, based on glycosaminoglycans and other polysaccharides, showed a very high association capacity for some delicate bioactive proteins such as growth factors, but a limited capacity to associate negatively charged molecules, such as pDNA and siRNA. However, the versatility of these nanosystems in terms of composition allowed us to customise the association of active ingredients and their physicochemical characteristics. Concretely, we prepared and incorporated gelatine cationized with spermine (CGsp) to their composition. The resulting modified formulations were characterised by a nanometric size (150-340 nm) and offer the possibility to modulate their zeta potential (from -35 to 28 mV), providing an efficient association of nucleic acids. The biological evaluation of these optimised nanosystems revealed that they are able to be internalised in vivo into corneal and conjunctival tissues and also to provide a significant siRNA gene silencing effect.

  18. Carbon and nitrogen biogeochemistry in the ocean: A study using stable isotope natural abundance

    NASA Technical Reports Server (NTRS)

    Rau, G. H.; Desmarais, David J.

    1985-01-01

    Determining the biogeochemical pathways traveled by carbon and nitrogen in the ocean is fundamental to the understanding of how the ocean participates in the cycling of these elements within the biosphere. Because biological production, metabolism, and respiration can significantly alter the natural abundance of C-13 and N-15, these abundances can provide important information about the nature of these biological processes and their variability in the marine environment. The research initially seeks to characterize the spatial and temporal patterns of stable isotope abundances in organic matter, and to relate these abundances to C and N biogeochemical processes within selected areas of the northeastern Pacific Ocean.

  19. Temporary skin grafts based on hybrid graphene oxide-natural biopolymer nanofibers as effective wound healing substitutes: pre-clinical and pathological studies in animal models.

    PubMed

    Mahmoudi, N; Eslahi, N; Mehdipour, A; Mohammadi, M; Akbari, M; Samadikuchaksaraei, A; Simchi, A

    2017-05-01

    In recent years, temporary skin grafts (TSG) based on natural biopolymers modified with carbon nanostructures have received considerable attention for wound healing. Developments are required to improve physico-mechanical properties of these materials to match to natural skins. Additionally, in-deep pre-clinical examinations are necessary to ensure biological performance and toxicity effect in vivo. In the present work, we show superior acute-wound healing effect of graphene oxide nanosheets embedded in ultrafine biopolymer fibers (60 nm) on adult male rats. Nano-fibrous chitosan-based skin grafts crosslinked by Genepin with physico-mechanical properties close to natural skins were prepared by electrospinning of highly concentrated chitosan- polyvinylpyrrolidone solutions containing graphene oxide (GO) nanosheets. No surfactants and organic solvents were utilized to ensure high biocompatibility of the fibrous structure. In vitro evaluations by human skin fibroblast cells including live and dead assay and MTT results show that GO promote cell viability of porous nanofibrous membrane while providing enhanced bactericidal capacity. In vivo studies on rat's skin determine accelerated healing effect, i.e. a large open wound (1.5 × 1.5 cm(2)) is fully regenerated after 14-day of post operation while healing is observed for sterile gauze sponge (as the control). Pathological studies support thick dermis formation and complete epithelialization in the presence of 1.5 wt% GO nanosheets. Over 99% wound healing occurs after 21 days for the injury covered with TSG containing 1.5 wt% GO while this would takes weeks for the control. Therefore, the developed materials have a high potential to be used as TSG as pre-clinical testing has shown.

  20. Transposases are the most abundant, most ubiquitous genes in nature

    PubMed Central

    Aziz, Ramy K.; Breitbart, Mya; Edwards, Robert A.

    2010-01-01

    Genes, like organisms, struggle for existence, and the most successful genes persist and widely disseminate in nature. The unbiased determination of the most successful genes requires access to sequence data from a wide range of phylogenetic taxa and ecosystems, which has finally become achievable thanks to the deluge of genomic and metagenomic sequences. Here, we analyzed 10 million protein-encoding genes and gene tags in sequenced bacterial, archaeal, eukaryotic and viral genomes and metagenomes, and our analysis demonstrates that genes encoding transposases are the most prevalent genes in nature. The finding that these genes, classically considered as selfish genes, outnumber essential or housekeeping genes suggests that they offer selective advantage to the genomes and ecosystems they inhabit, a hypothesis in agreement with an emerging body of literature. Their mobile nature not only promotes dissemination of transposable elements within and between genomes but also leads to mutations and rearrangements that can accelerate biological diversification and—consequently—evolution. By securing their own replication and dissemination, transposases guarantee to thrive so long as nucleic acid-based life forms exist. PMID:20215432

  1. Natural variability in abundance of prevalent soybean proteins.

    PubMed

    Natarajan, Savithiry S

    2010-12-01

    Soybean is an inexpensive source of protein for humans and animals. Genetic modifications (GMO) to soybean have become inevitable on two fronts, both quality and yield will need to improve to meet increasing global demand. To ensure the safety of the crop for consumers it is important to determine the natural variation in seed protein constituents as well as any unintended changes that may occur in the GMO as a result of genetic modification. Understanding the natural variation of seed proteins in wild and cultivated soybeans that have been used in conventional soybean breeding programs is critical for determining unintended protein expression in GMO soybeans. In recent years, proteomic technologies have been used as an effective analytical tool for examining modifications of protein profiles. We have standardized and applied these technologies to determine and quantify the spectrum of proteins present in soybean seed. We used two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), and liquid chromatography mass spectrometry (LC-MS) for the separation, quantification, and identification of different classes of soybean seed proteins. We have observed significant variations in different classes of proteins, including storage, allergen and anti-nutritional protein profiles, between non-GMO cultivated and wild soybean varieties. This information is useful for scientists and regulatory agencies to determine whether the unintended expression of proteins found in transgenic soybean is within the range of natural variation.

  2. Preparation of Biopolymer Aerogels Using Green Solvents

    PubMed Central

    Subrahmanyam, Raman; Gurikov, Pavel; Meissner, Imke; Smirnova, Irina

    2016-01-01

    Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm). PMID:27403649

  3. Abundance and Utility: For Military Operations, Liquid Fuels Remain a Solid Choice over Natural Gas

    DTIC Science & Technology

    2014-08-01

    and combat support vehicles, ships, and aircraft, the adoption of natural gas —whether as compressed natural gas (CNG) or liquefied natural gas (LNG...tacticaldefensemedia.com16 | DoD Power & Energy Fall 2014 For Military Operations, Liquid Fuels Remain a Solid Choice over Natural Gas By Bret...Strogen and Patrick Lobner Abundance and Utility Fueling the Force Natural Gas M ilitary energy strategists often recount the British Royal Navy’s decision

  4. Detection of human muscle glycogen by natural abundance /sup 13/C NMR

    SciTech Connect

    Avison, M.J.; Rothman, D.L.; Nadel, E.; Shulman, R.G.

    1988-03-01

    Natural abundance /sup 13/C nuclear magnetic resonance spectroscopy was used to detect signals from glycogen in the human gastrocnemius muscle. The reproducibility of the measurement was demonstrated, and the ability to detect dynamic changes was confirmed by measuring a decrease in muscle glycogen levels after exercise and its subsequent repletion. Single frequency gated /sup 1/H decoupling was used to obtain decoupled natural abundance /sup 13/C NMR spectra of the C-1 position of muscle glycogen.

  5. Biopolymer colloids for controlling and templating inorganic synthesis

    PubMed Central

    Preiss, Laura C; Landfester, Katharina

    2014-01-01

    Summary Biopolymers and biopolymer colloids can act as controlling agents and templates not only in many processes in nature, but also in a wide range of synthetic approaches. Inorganic materials can be either synthesized ex situ and later incorporated into a biopolymer structuring matrix or grown in situ in the presence of biopolymers. In this review, we focus mainly on the latter case and distinguish between the following possibilities: (i) biopolymers as controlling agents of nucleation and growth of inorganic materials; (ii) biopolymers as supports, either as molecular supports or as carrier particles acting as cores of core–shell structures; and (iii) so-called “soft templates”, which include on one hand stabilized droplets, micelles, and vesicles, and on the other hand continuous scaffolds generated by gelling biopolymers. PMID:25551041

  6. Plant characteristics associated with natural enemy abundance at Michigan native plants.

    PubMed

    Fiedler, A K; Landis, D A

    2007-08-01

    Habitat management is a type of conservation biological control that focuses on increasing natural enemy populations by providing them with plant resources such as pollen and nectar. Insects are known to respond to a variety of plant characteristics in their search for plant-provided resources. A better understanding of the specific characteristics used by natural enemy insects in selecting these resources could greatly improve efficiency in screening plants for habitat management. We examined 5 previously tested and widely recommended resource plants and 43 candidate plants to test whether the number and type of natural enemies and herbivores at each plant were predicted by plant characteristics including: period of peak bloom, floral area, maximum flower height, hue, chroma, and corolla size. Natural enemy abundance increased with week of peak bloom and greater floral area across all plants tested. Ordination of plant characteristics indicated that increasing floral area, period of peak bloom, maximum flower height, and decreasing corolla width grouped together into a single principal component. Both natural enemy and herbivore abundance increased significantly with the principal component for this set of characteristics, but the relationship with herbivore abundance was weaker. These results indicate that, for a given time of the season, selection of plants with the largest floral area has potential to increase natural enemy abundance in habitat management plantings and streamline plant selection for habitat management.

  7. A temperature responsive biopolymer for mercury remediation.

    PubMed

    Kostal, Jan; Mulchandani, Ashok; Gropp, Katie E; Chen, Wilfred

    2003-10-01

    Tunable biopolymers based on elastin-like polypeptides (ELP) were engineered for the selective removal of mercury. ELP undergoes a reversible thermal precipitation within a wide range of temperatures and was exploited to enable easy recovery of the sequestered mercury. A bacterial metalloregulatory protein, MerR, which binds mercury with an unusually high affinity and selectivity, was fused to the ELP to provide the highly selective nature of the biopolymers. Selective binding of mercury was demonstrated at an expected ratio of 0.5 mercury/biopolymer, and minimal binding of competing heavy metals (cadmium, nickel, and zinc), even at 100-fold excess, was observed. The sequestered mercury was extracted easily, enabling continuous reuse of the biopolymers. In repeating cycles, mercury concentration was reduced to ppb levels, satisfying even drinking water limits. Utility of the biopolymers with mercury-contaminated Lake Elsinore water was demonstrated with no decrease in efficiency. The nanoscale biopolymers reported here using metalloregulatory proteins represent a "green" technology for environmentally benign mercury removal. As nature offers a wide selection of specific metalloregulatory proteins, this technology offers promising solutions to remediation of other important pollutants such as arsenic or chromium.

  8. Recent advances in biopolymers and biopolymer-based nanocomposites for food packaging materials.

    PubMed

    Tang, X Z; Kumar, P; Alavi, S; Sandeep, K P

    2012-01-01

    Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.

  9. APPLICATION OF FLUORESCENCE SPECTROSCOPIC TECHNIQUES AND PROBES TO THE DETECTION OF BIOPOLYMER DEGRADATION IN NATURAL ENVIRONMENTS. (R825159)

    EPA Science Inventory

    The activities and substrate specificities of extracellular enzymes in natural systems are not well understood, despite their critical role in microbial remineralization of organic carbon. These enzymes initiate organic carbon degradation by selectively hydrolyzing high molecular...

  10. Natural variation in stomatal abundance of Arabidopsis thaliana includes cryptic diversity for different developmental processes

    PubMed Central

    Delgado, Dolores; Alonso-Blanco, Carlos; Fenoll, Carmen; Mena, Montaña

    2011-01-01

    Background and Aims Current understanding of stomatal development in Arabidopsis thaliana is based on mutations producing aberrant, often lethal phenotypes. The aim was to discover if naturally occurring viable phenotypes would be useful for studying stomatal development in a species that enables further molecular analysis. Methods Natural variation in stomatal abundance of A. thaliana was explored in two collections comprising 62 wild accessions by surveying adaxial epidermal cell-type proportion (stomatal index) and density (stomatal and pavement cell density) traits in cotyledons and first leaves. Organ size variation was studied in a subset of accessions. For all traits, maternal effects derived from different laboratory environments were evaluated. In four selected accessions, distinct stomatal initiation processes were quantitatively analysed. Key Results and Conclusions Substantial genetic variation was found for all six stomatal abundance-related traits, which were weakly or not affected by laboratory maternal environments. Correlation analyses revealed overall relationships among all traits. Within each organ, stomatal density highly correlated with the other traits, suggesting common genetic bases. Each trait correlated between organs, supporting supra-organ control of stomatal abundance. Clustering analyses identified accessions with uncommon phenotypic patterns, suggesting differences among genetic programmes controlling the various traits. Variation was also found in organ size, which negatively correlated with cell densities in both organs and with stomatal index in the cotyledon. Relative proportions of primary and satellite lineages varied among the accessions analysed, indicating that distinct developmental components contribute to natural diversity in stomatal abundance. Accessions with similar stomatal indices showed different lineage class ratios, revealing hidden developmental phenotypes and showing that genetic determinants of primary and

  11. Natural abundance 17O DNP two-dimensional and surface-enhanced NMR spectroscopy

    DOE PAGES

    Perras, Frédéric A.; Kobayashi, Takeshi; Pruski, Marek

    2015-06-22

    Due to its extremely low natural abundance and quadrupolar nature, the 17O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, the applicability of dynamic nuclear polarization (DNP), which leads to sensitivity enhancements of 2 orders of magnitude, to 17O is wrought with challenges due to the lack of spin diffusion and low polarization transfer efficiency from 1H. Here, we demonstrate new DNP-based measurements that extend 17O solid-state NMR beyond its current capabilities. The use of the PRESTO technique instead of conventional 1H–17O cross-polarization greatly improves the sensitivity and enables the facile measurementmore » of undistorted line shapes and two-dimensional 1H–17O HETCOR NMR spectra as well as accurate internuclear distance measurements at natural abundance. This was applied for distinguishing hydrogen-bonded and lone 17O sites on the surface of silica gel; the one-dimensional spectrum of which could not be used to extract such detail. As a result, this greatly enhanced sensitivity has enabled, for the first time, the detection of surface hydroxyl sites on mesoporous silica at natural abundance, thereby extending the concept of DNP surface-enhanced NMR spectroscopy to the 17O nuclide.« less

  12. Natural Genetic Variation Influences Protein Abundances in C. elegans Developmental Signalling Pathways

    PubMed Central

    Singh, Kapil Dev; Roschitzki, Bernd; Snoek, L. Basten; Grossmann, Jonas; Zheng, Xue; Elvin, Mark; Kamkina, Polina; Schrimpf, Sabine P.; Poulin, Gino B.; Kammenga, Jan E.; Hengartner, Michael O.

    2016-01-01

    Complex traits, including common disease-related traits, are affected by many different genes that function in multiple pathways and networks. The apoptosis, MAPK, Notch, and Wnt signalling pathways play important roles in development and disease progression. At the moment we have a poor understanding of how allelic variation affects gene expression in these pathways at the level of translation. Here we report the effect of natural genetic variation on transcript and protein abundance involved in developmental signalling pathways in Caenorhabditis elegans. We used selected reaction monitoring to analyse proteins from the abovementioned four pathways in a set of recombinant inbred lines (RILs) generated from the wild-type strains N2 (Bristol) and CB4856 (Hawaii) to enable quantitative trait locus (QTL) mapping. About half of the cases from the 44 genes tested showed a statistically significant change in protein abundance between various strains, most of these were however very weak (below 1.3-fold change). We detected a distant QTL on the left arm of chromosome II that affected protein abundance of the phosphatidylserine receptor protein PSR-1, and two separate QTLs that influenced embryonic and ionizing radiation-induced apoptosis on chromosome IV. Our results demonstrate that natural variation in C. elegans is sufficient to cause significant changes in signalling pathways both at the gene expression (transcript and protein abundance) and phenotypic levels. PMID:26985669

  13. Increased natural mortality at low abundance can generate an Allee effect in a marine fish.

    PubMed

    Kuparinen, Anna; Hutchings, Jeffrey A

    2014-10-01

    Negative density-dependent regulation of population dynamics promotes population growth at low abundance and is therefore vital for recovery following depletion. Inversely, any process that reduces the compensatory density-dependence of population growth can negatively affect recovery. Here, we show that increased adult mortality at low abundance can reverse compensatory population dynamics into its opposite-a demographic Allee effect. Northwest Atlantic cod (Gadus morhua) stocks collapsed dramatically in the early 1990s and have since shown little sign of recovery. Many experienced dramatic increases in natural mortality, ostensibly attributable in some populations to increased predation by seals. Our findings show that increased natural mortality of a magnitude observed for overfished cod stocks has been more than sufficient to fundamentally alter the dynamics of density-dependent population regulation. The demographic Allee effect generated by these changes can slow down or even impede the recovery of depleted populations even in the absence of fishing.

  14. High-resolution NMR of hydrogen in organic solids by DNP enhanced natural abundance deuterium spectroscopy

    NASA Astrophysics Data System (ADS)

    Rossini, Aaron J.; Schlagnitweit, Judith; Lesage, Anne; Emsley, Lyndon

    2015-10-01

    We demonstrate that high field (9.4 T) dynamic nuclear polarization (DNP) at cryogenic (∼100 K) sample temperatures enables the rapid acquisition of natural abundance 1H-2H cross-polarization magic angle spinning (CPMAS) solid-state NMR spectra of organic solids. Spectra were obtained by impregnating substrates with a solution of the stable DNP polarizing agent TEKPol in tetrachloroethane. Tetrachloroethane is a non-solvent for the solids, and the unmodified substrates are then polarized through spin diffusion. High quality natural abundance 2H CPMAS spectra of histidine hydrochloride monohydrate, glycylglycine and theophylline were acquired in less than 2 h, providing direct access to hydrogen chemical shifts and quadrupolar couplings. The spectral resolution of the 2H solid-state NMR spectra is comparable to that of 1H spectra obtained with state of the art homonuclear decoupling techniques.

  15. Determination of lithium isotopes at natural abundance levels by atomic absorption spectrometry

    USGS Publications Warehouse

    Meier, A.L.

    1982-01-01

    The relationships of the absorption of 6Li and 7Li hollow cathode lamp emissions are used to determine lithium isotopic composition in the natural abundance range of geologic materials. Absorption was found to have a nonlinear dependence upon total lithium concentration and isotopic composition. A method using nonlinear equations to describe the relationship of the absorption of 6Li and 7Li lamp radiation is proposed as a means of calculating isotopic composition that is independent of total lithium concentration.

  16. The potential of silk and silk-like proteins as natural mucoadhesive biopolymers for controlled drug delivery

    NASA Astrophysics Data System (ADS)

    Brooks, Amanda

    2015-11-01

    Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1) deliver sensitive biologic molecules, (2) promote intimate contact between the mucosa and the drug, and (3) prolong the drug’s local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  17. The Potential of Silk and Silk-Like Proteins as Natural Mucoadhesive Biopolymers for Controlled Drug Delivery

    PubMed Central

    Brooks, Amanda E.

    2015-01-01

    Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1) deliver sensitive biologic molecules, (2) promote intimate contact between the mucosa and the drug, and (3) prolong the drug's local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery. PMID:26636069

  18. The relative importance of resources and natural enemies in determining herbivore abundance: thistles, tephritids and parasitoids.

    PubMed

    Walker, Matthew; Hartley, Susan E; Jones, T Hefin

    2008-09-01

    1. The relative importance of host-plant resources and natural enemies in influencing the abundance of insect herbivores was investigated in potted plant and natural population experiments, using tephritid (Diptera: Tephritidae) flies, their host plant, creeping thistle Cirsium arvense, and their Hymenoptera parasitoids. 2. Experimental manipulation of host-plant quality (i.e. levels of host-plant nutrients) and resource availability (i.e. the number of buds) increased tephritid abundance. There was no evidence that the seed-feeding tephritid fly Xyphosia miliaria preferentially oviposited on fertilized C. arvense. 3. At low thistle densities, X. miliaria showed a constant rate of resource exploitation. At higher thistle densities, a threshold was detected, above which additional buds were not attacked. 4. Parasitism attack was variable across host (tephritid) densities but levels of parasitism were consistently higher on the fertilized thistles. 5. Experimental manipulation of host-plant quality and resource availability (quantity) not only directly affects the tephritid population but also, indirectly, leads to high rates of parasitism. Both chemical and physical characteristics of host plants affect the performance of natural enemies. 6. Both top-down and bottom-up forces act to influence tephritid abundance, with bottom-up influences appearing to be the most important.

  19. Effects of abundance on infection in natural populations: field voles and cowpox virus.

    PubMed

    Begon, Michael; Telfer, Sandra; Burthe, Sarah; Lambin, Xavier; Smith, Matthew J; Paterson, Steve

    2009-03-01

    Detailed results on the dynamics of cowpox virus infection in four natural populations of the field vole, Microtus agrestis, are presented. Populations were sampled every 4 weeks (8 weeks in mid-winter) for 6 years. The purpose was to examine the relationships between overall or susceptible host abundance (N, S) and both the number of infected hosts (I) and the prevalence of infection (I/N). Overall, both I and I/N increased with N. However, evidence for a threshold abundance, below which infection was not found, was at best equivocal in spite of the wide range of abundances sampled. Cross-correlation analyses reflected annual and multi-annual cycles in N, I, S and I/N, but whereas N was most strongly correlated with contemporary values of I and I/N, in the case of S, the strongest correlations were with values 1 to 2 months preceding the values of I and I/N. There was no evidence for a 'juvenile dilution effect' (prevalence decreasing with abundance as new susceptibles flush into the population) and only weak evidence of a time-delayed effect of abundance on the number infected. We argue that these effects may occur only in systems with characteristics that are not found here. Transfer function analyses, which have been neglected in epidemiology, were applied. These models, with ln(S) as the input parameter, in spite of their simplicity, could be linked closely to conventional formulations of the transmission process and were highly effective in predicting the number infected. By contrast, transfer function models with ln(N) as the input parameter were less successful in predicting the number infected and/or were more complex and more difficult to interpret. Nonetheless, overall, we contend that while monitoring numbers susceptible has most to offer, monitoring overall abundance may provide valuable insights into the dynamics of infection.

  20. Effect of Environmental Factors on Cyanobacterial Abundance and Cyanotoxins Production in Natural and Drinking Water, Bangladesh.

    PubMed

    Affan, Abu; Khomavis, Hisham S; Al-Harbi, Salim Marzoog; Haque, Mahfuzul; Khan, Saleha

    2015-02-01

    Cyanobacterial blooms commonly appear during the summer months in ponds, lakes and reservoirs in Bangladesh. In these areas, fish mortality, odorous water and fish and human skin irritation and eye inflammation have been reported. The influence of physicochemical factors on the occurrence of cyanobacteria and its toxin levels were evaluated in natural and drinking water in Bangladesh. A highly sensitive immunosorbent assay was used to detect microcystins (MCs). Cyanobacteria were found in 22 of 23 samples and the dominant species were Microcystis aeruginosa, followed by Microcystisflosaquae, Anabeana crassa and Aphanizomenon flosaquae. Cyanobacterial abundance varied from 39 to 1315 x 10(3) cells mL(-1) in natural water and 31 to 49 x 10(3) cells mL(-1) in tap water. MC concentrations were 25-82300 pg mL(-1) with the highest value measured in the fish research pond, followed by Ishakha Lake. In tap water, MC concentrations ranged from 30-32 pg mL(-1). The correlation between nitrate-nitrogen (NO3-N) concentration and cyanobacterial cell abundance was R2 = 0.62 while that between cyanobacterial abundance and MC concentration was R2 = 0.98. The increased NO3-N from fish feed, organic manure, poultry and dairy farm waste and fertilizer from agricultural land eutrophicated the water bodies and triggered cyanobacterial bloom formation. The increased amount of cyanobacteria produced MCs, subsequently reducing the water quality.

  1. Soil Carbon-Fixation Rates and Associated Bacterial Diversity and Abundance in Three Natural Ecosystems.

    PubMed

    Lynn, Tin Mar; Ge, Tida; Yuan, Hongzhao; Wei, Xiaomeng; Wu, Xiaohong; Xiao, Keqing; Kumaresan, Deepak; Yu, San San; Wu, Jinshui; Whiteley, Andrew S

    2017-04-01

    CO2 assimilation by autotrophic microbes is an important process in soil carbon cycling, and our understanding of the community composition of autotrophs in natural soils and their role in carbon sequestration of these soils is still limited. Here, we investigated the autotrophic C incorporation in soils from three natural ecosystems, i.e., wetland (WL), grassland (GR), and forest (FO) based on the incorporation of labeled C into the microbial biomass. Microbial assimilation of (14)C ((14)C-MBC) differed among the soils from three ecosystems, accounting for 14.2-20.2% of (14)C-labeled soil organic carbon ((14)C-SOC). We observed a positive correlation between the cbbL (ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large-subunit gene) abundance, (14)C-SOC level, and (14)C-MBC concentration confirming the role of autotrophic bacteria in soil carbon sequestration. Distinct cbbL-bearing bacterial communities were present in each soil type; form IA and form IC RubisCO-bearing bacteria were most abundant in WL, followed by GR soils, with sequences from FO soils exclusively derived from the form IC clade. Phylogenetically, the diversity of CO2-fixing autotrophs and CO oxidizers differed significantly with soil type, whereas cbbL-bearing bacterial communities were similar when assessed using coxL. We demonstrate that local edaphic factors such as pH and salinity affect the C-fixation rate as well as cbbL and coxL gene abundance and diversity. Such insights into the effect of soil type on the autotrophic bacterial capacity and subsequent carbon cycling of natural ecosystems will provide information to enhance the sustainable management of these important natural ecosystems.

  2. Symbiotic nitrogen fixation in an arid ecosystem measured by sup 15 N natural abundance

    SciTech Connect

    Johnson, G.V. )

    1990-05-01

    Plants dependent on nitrogen fixation have an {sup 15}N abundance similar to the atmosphere, while non-nitrogen fixing plants usually are enriched in {sup 15}N and are similar to soil nitrogen values. The natural abundance of {sup 15}N in leaf tissues and soils was determined to evaluate symbiotic nitrogen fixation by several legumes and actinorhizal species in the Sevilleta Long-term Ecological Research area in central New Mexico. Comparison of {delta}{sup 15}N values for the legume Prosopis glandulosa (mesquite) to adjacent Atriplex canascens (fourwing saltbush) indicated that P. glandulosa obtained 66% of its nitrogen by fixation. The legume Hoffmanseggia jamesii was found to be utilizing soil nitrogen. The {delta}{sup 15}N values for the actinorhizal plants, Elaeagnus angustifolia and Cercocarpus montanus, while below values for soil nitrogen, did not differ from associated non-fixing plants.

  3. Understanding the Nature of Stellar Chemical Abundance Distributions in Nearby Stellar Systems

    NASA Astrophysics Data System (ADS)

    Lee, Duane Morris

    Since stars retain signatures of their galactic origins in their chemical compositions, we can exploit the chemical abundance distributions that we observe in stellar systems to put constraints on the nature of their progenitors. In this thesis, I present results from three projects aimed at understanding how high resolution spectroscopic observations of nearby stellar systems might be interpreted. The first project presents one possible explanation for the origin of peculiar abundance distributions observed in ultra-faint dwarf satellites of the Milky Way. The second project explores to what extent the distribution of chemical elements in the stellar halo can be used to trace Galactic accretion history from the birth of the Galaxy to the present day. Finally, a third project focuses on developing an input optimization algorithm for the second project to produce better estimates of halo accretion histories. In conclusion, I propose some other new ways to use statistical models and techniques along with chemical abundance distribution data to uncover galactic histories.

  4. Natural abundances of carbon isotopes in acetate from a coastal marine sediment

    NASA Technical Reports Server (NTRS)

    Blair, N. E.; Martens, C. S.; Des Marais, D. J.

    1987-01-01

    Measurements of the natural abundances of carbon isotopes were made in acetate samples isolated from the anoxic marine sediment of Cape Lookout Bight, North Carolina. The typical value of the total acetate carbon isotope ratio (delta 13C) was -16.1 +/- 0.2 per mil. The methyl and carboxyl groups were determined to be -26.4 +/- 0.3 and -6.0 +/- 0.3 per mil, respectively, for one sample. The isotopic composition of the acetate is thought to have resulted from isotopic discriminations that occurred during the cycling of that molecule. Measurements of this type, which have not been made previously in the natural environment, may provide information about the dominant microbial pathways in anoxic sediments as well as the processes that influence the carbon isotopic composition of biogenic methane from many sources.

  5. Coupled biopolymer networks

    NASA Astrophysics Data System (ADS)

    Schwarz, J. M.; Zhang, Tao

    2015-03-01

    The actin cytoskeleton provides the cell with structural integrity and allows it to change shape to crawl along a surface, for example. The actin cytoskeleton can be modeled as a semiflexible biopolymer network that modifies its morphology in response to both external and internal stimuli. Just inside the inner nuclear membrane of a cell exists a network of filamentous lamin that presumably protects the heart of the cell nucleus--the DNA. Lamins are intermediate filaments that can also be modeled as semiflexible biopolymers. It turns out that the actin cytoskeletal biopolymer network and the lamin biopolymer network are coupled via a sequence of proteins that bridge the outer and inner nuclear membranes. We, therefore, probe the consequences of such a coupling via numerical simulations to understand the resulting deformations in the lamin network in response to perturbations in the cytoskeletal network. Such study could have implications for mechanical mechanisms of the regulation of transcription, since DNA--yet another semiflexible polymer--contains lamin-binding domains, and, thus, widen the field of epigenetics.

  6. Abundance and phenology patterns of two pond-breeding salamanders determine species interactions in natural populations.

    PubMed

    Anderson, Thomas L; Hocking, Daniel J; Conner, Christopher A; Earl, Julia E; Harper, Elizabeth B; Osbourn, Michael S; Peterman, William E; Rittenhouse, Tracy A G; Semlitsch, Raymond D

    2015-03-01

    Phenology often determines the outcome of interspecific interactions, where early-arriving species often dominate interactions over those arriving later. The effects of phenology on species interactions are especially pronounced in aquatic systems, but the evidence is largely derived from experimental studies. We examined whether differences in breeding phenology between two pond-breeding salamanders (Ambystoma annulatum and A. maculatum) affected metamorph recruitment and demographic traits within natural populations, with the expectation that the fall-breeding A. annulatum would negatively affect the spring-breeding A. maculatum. We monitored populations of each species at five ponds over 4 years using drift fences. Metamorph abundance and survival of A. annulatum were affected by intra- and interspecific processes, whereas metamorph size and date of emigration were primarily influenced by intraspecific effects. Metamorph abundance, snout-vent length, date of emigration and survival for A. maculatum were all predicted by combinations of intra- and interspecific effects, but often showed negative relationships with A. annulatum metamorph traits and abundance. Size and date of metamorphosis were strongly correlated within each species, but in opposite patterns (negative for A. annulatum and positive for A. maculatum), suggesting that the two species use alternative strategies to enhance terrestrial survival and that these factors may influence their interactions. Our results match predictions from experimental studies that suggest recruitment is influenced by intra- and interspecific processes which are determined by phenological differences between species. Incorporating spatiotemporal variability when modeling population dynamics is necessary to understand the importance of phenology in species interactions, especially as shifts in phenology occur under climate change.

  7. Natural abundance variations in stable isotopes and their potential uses in animal physiological ecology.

    PubMed

    Gannes, L Z; Martínez del Rio, C; Koch, P

    1998-03-01

    Chemical, biological, and physical processes lead to distinctive "isotopic signatures" in biological materials that allow tracing of the origins of organic substances. Isotopic variation has been extensively used by plant physiological ecologists and by paleontologists, and recently ecologists have adopted the use of stable isotopes to measure ecosystem patterns and processes. To date, animal physiological ecologists have made minimal use of naturally occurring stable isotopes as tracers. Here we provide a review of the current and potential uses of naturally occurring stable isotopes in animal physiological ecology. We outline the physical and biological processes that lead to variation in isotopic abundance in plants and animals. We summarize current uses in animal physiological ecology (diet reconstruction and animal movement patterns), and suggest areas of research where the use of stable isotopes can be fruitful (protein balance and turnover and the allocation of dietary nutrients). We argue that animal physiological ecologists can benefit from including the measurement of naturally occurring stable isotopes in their battery of techniques. We also argue that animal physiologists can make an important contribution to the emerging field of stable isotopes in biology by testing experimentally the plethora of assumptions upon which the techniques rely.

  8. Natural abundance 14N and 15N solid-state NMR of pharmaceuticals and their polymorphs

    DOE PAGES

    Veinberg, Stanislav L.; Johnston, Karen E.; Jaroszewicz, Michael J.; ...

    2016-06-08

    14N ultra-wideline (UW), 1H{15N} indirectly-detected HETCOR (idHETCOR) and 15N dynamic nuclear polarization (DNP) solid-state NMR (SSNMR) experiments, in combination with plane-wave density functional theory (DFT) calculations of 14N EFG tensors, were utilized to characterize a series of nitrogen-containing active pharmaceutical ingredients (APIs), including HCl salts of scopolamine, alprenolol, isoprenaline, acebutolol, dibucaine, nicardipine, and ranitidine. Here, a case study applying these methods for the differentiation of polymorphs of bupivacaine HCl is also presented. All experiments were conducted upon samples with naturally-abundant nitrogen isotopes. For most of the APIs, it was possible to acquire frequency-stepped UW 14N SSNMR spectra of stationarymore » samples, which display powder patterns corresponding to pseudo-tetrahedral (i.e., RR'R"NH+ and RR'NH2+) or other (i.e., RNH2 and RNO2) nitrogen environments.« less

  9. Biosynthesis of gallic acid in Rhus typhina: discrimination between alternative pathways from natural oxygen isotope abundance.

    PubMed

    Werner, Roland A; Rossmann, Andreas; Schwarz, Christine; Bacher, Adelbert; Schmidt, Hanns-Ludwig; Eisenreich, Wolfgang

    2004-10-01

    The biosynthetic pathway of gallic acid in leaves of Rhus typhina is studied by oxygen isotope ratio mass spectrometry at natural oxygen isotope abundance. The observed delta18O-values of gallic acid indicate an 18O-enrichment of the phenolic oxygen atoms of more than 30 per thousand above that of the leaf water. This enrichment implies biogenetical equivalence with oxygen atoms of carbohydrates but not with oxygen atoms introduced by monooxygenase activation of molecular oxygen. It can be concluded that all phenolic oxygen atoms of gallic acid are retained from the carbohydrate-derived precursor 5-dehydroshikimate. This supports that gallic acid is synthesized entirely or predominantly by dehydrogenation of 5-dehydroshikimate.

  10. Natural-abundance solid-state 2H NMR spectroscopy at high magnetic field.

    PubMed

    Aliev, Abil E; Mann, Sam E; Iuga, Dinu; Hughes, Colan E; Harris, Kenneth D M

    2011-06-09

    High-resolution solid-state (2)H NMR spectroscopy provides a method for measuring (1)H NMR chemical shifts in solids and is advantageous over the direct measurement of high-resolution solid-state (1)H NMR spectra, as it requires only the application of routine magic angle sample spinning (MAS) and routine (1)H decoupling methods, in contrast to the requirement for complex pulse sequences for homonuclear (1)H decoupling and ultrafast MAS in the case of high-resolution solid-state (1)H NMR. However, a significant obstacle to the routine application of high-resolution solid-state (2)H NMR is the very low natural abundance of (2)H, with the consequent problem of inherently low sensitivity. Here, we explore the feasibility of measuring (2)H MAS NMR spectra of various solids with natural isotopic abundances at high magnetic field (850 MHz), focusing on samples of amino acids, peptides, collagen, and various organic solids. The results show that high-resolution solid-state (2)H NMR can be used successfully to measure isotropic (1)H chemical shifts in favorable cases, particularly for mobile functional groups, such as methyl and -N(+)H(3) groups, and in some cases phenyl groups. Furthermore, we demonstrate that routine (2)H MAS NMR measurements can be exploited for assessing the relative dynamics of different functional groups in a molecule and for assessing whole-molecule motions in the solid state. The magnitude and field-dependence of second-order shifts due to the (2)H quadrupole interaction are also investigated, on the basis of analysis of simulated and experimental (1)H and (2)H MAS NMR spectra of fully deuterated and selectively deuterated samples of the α polymorph of glycine at two different magnetic field strengths.

  11. Growing three-dimensional biomorphic graphene powders using naturally abundant diatomite templates towards high solution processability

    NASA Astrophysics Data System (ADS)

    Chen, Ke; Li, Cong; Shi, Liurong; Gao, Teng; Song, Xiuju; Bachmatiuk, Alicja; Zou, Zhiyu; Deng, Bing; Ji, Qingqing; Ma, Donglin; Peng, Hailin; Du, Zuliang; Rümmeli, Mark Hermann; Zhang, Yanfeng; Liu, Zhongfan

    2016-11-01

    Mass production of high-quality graphene with low cost is the footstone for its widespread practical applications. We present herein a self-limited growth approach for producing graphene powders by a small-methane-flow chemical vapour deposition process on naturally abundant and industrially widely used diatomite (biosilica) substrates. Distinct from the chemically exfoliated graphene, thus-produced biomorphic graphene is highly crystallized with atomic layer-thickness controllability, structural designability and less noncarbon impurities. In particular, the individual graphene microarchitectures preserve a three-dimensional naturally curved surface morphology of original diatom frustules, effectively overcoming the interlayer stacking and hence giving excellent dispersion performance in fabricating solution-processible electrodes. The graphene films derived from as-made graphene powders, compatible with either rod-coating, or inkjet and roll-to-roll printing techniques, exhibit much higher electrical conductivity (~110,700 S m-1 at 80% transmittance) than previously reported solution-based counterparts. This work thus puts forward a practical route for low-cost mass production of various powdery two-dimensional materials.

  12. Growing three-dimensional biomorphic graphene powders using naturally abundant diatomite templates towards high solution processability

    PubMed Central

    Chen, Ke; Li, Cong; Shi, Liurong; Gao, Teng; Song, Xiuju; Bachmatiuk, Alicja; Zou, Zhiyu; Deng, Bing; Ji, Qingqing; Ma, Donglin; Peng, Hailin; Du, Zuliang; Rümmeli, Mark Hermann; Zhang, Yanfeng; Liu, Zhongfan

    2016-01-01

    Mass production of high-quality graphene with low cost is the footstone for its widespread practical applications. We present herein a self-limited growth approach for producing graphene powders by a small-methane-flow chemical vapour deposition process on naturally abundant and industrially widely used diatomite (biosilica) substrates. Distinct from the chemically exfoliated graphene, thus-produced biomorphic graphene is highly crystallized with atomic layer-thickness controllability, structural designability and less noncarbon impurities. In particular, the individual graphene microarchitectures preserve a three-dimensional naturally curved surface morphology of original diatom frustules, effectively overcoming the interlayer stacking and hence giving excellent dispersion performance in fabricating solution-processible electrodes. The graphene films derived from as-made graphene powders, compatible with either rod-coating, or inkjet and roll-to-roll printing techniques, exhibit much higher electrical conductivity (∼110,700 S m−1 at 80% transmittance) than previously reported solution-based counterparts. This work thus puts forward a practical route for low-cost mass production of various powdery two-dimensional materials. PMID:27819652

  13. Measurement of isotope abundance variations in nature by gravimetric spiking isotope dilution analysis (GS-IDA).

    PubMed

    Chew, Gina; Walczyk, Thomas

    2013-04-02

    Subtle variations in the isotopic composition of elements carry unique information about physical and chemical processes in nature and are now exploited widely in diverse areas of research. Reliable measurement of natural isotope abundance variations is among the biggest challenges in inorganic mass spectrometry as they are highly sensitive to methodological bias. For decades, double spiking of the sample with a mix of two stable isotopes has been considered the reference technique for measuring such variations both by multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) and multicollector-thermal ionization mass spectrometry (MC-TIMS). However, this technique can only be applied to elements having at least four stable isotopes. Here we present a novel approach that requires measurement of three isotope signals only and which is more robust than the conventional double spiking technique. This became possible by gravimetric mixing of the sample with an isotopic spike in different proportions and by applying principles of isotope dilution for data analysis (GS-IDA). The potential and principle use of the technique is demonstrated for Mg in human urine using MC-TIMS for isotopic analysis. Mg is an element inaccessible to double spiking methods as it consists of three stable isotopes only and shows great potential for metabolically induced isotope effects waiting to be explored.

  14. On the nature of sn stars. I. A detailed abundance study

    NASA Astrophysics Data System (ADS)

    Saffe, C.; Levato, H.

    2014-02-01

    The sn stars were first discoved by Abt & Levato when studying the spectral types in different open clusters. These stars present sharp Balmer lines, sharp metallic lines (C II, Si II, Ca II, Ti II, Fe II), and broad coreless He I lines. Some of the sn stars seem to be related to CP stars. Initially Abt & Levato proposed a shell-like nature to explain the sn stars, although this scenario was subsequently questioned. There is no general agreement about their origin. We aim to derive abundances for a sample of 9 stars, including sn and non-sn stars, to determine the possible relation between sn and CP stars and compare their chemical abundances. That most sn stars belong to open clusters allows us to search for a possible relation with fundamental parameters, including the age and rotation. We also study the possible contribution of different effects to the broad He I lines observed in these stars, such as Stark broadening and the possible He-stratification. Effective temperature and gravity were estimated by Strömgren photometry and then refined by requiring ionization and excitation equilibrium of Fe lines. We derived the abundances by fitting the observed spectra with synthetic spectra using an iterative procedure with the SYNTHE and ATLAS9 codes. We derived metallic abundances of 23 different chemical elements for 9 stars and obtained low projected rotational velocities for the sn stars in our sample (vsini up to 69 km s-1). We also compared 5 stars that belong to the same cluster (NGC 6475) and show that the sn characteristics appear in the 3 stars with the lower rotational velocity. However, the apparent preference of sn stars for objects with the lower vsini values should be taken with caution due to the small number of objects studied here. We analysed the photospheric chemical composition of sn stars and show that approximately ~40% of them display chemical peculiarities (such as He-weak and HgMn stars) within a range of temperature of 10 300 K-14 500 K

  15. Archaeal community diversity and abundance changes along a natural salinity gradient in estuarine sediments.

    PubMed

    Webster, Gordon; O'Sullivan, Louise A; Meng, Yiyu; Williams, Angharad S; Sass, Andrea M; Watkins, Andrew J; Parkes, R John; Weightman, Andrew J

    2015-02-01

    Archaea are widespread in marine sediments, but their occurrence and relationship with natural salinity gradients in estuarine sediments is not well understood. This study investigated the abundance and diversity of Archaea in sediments at three sites [Brightlingsea (BR), Alresford (AR) and Hythe (HY)] along the Colne Estuary, using quantitative real-time PCR (qPCR) of 16S rRNA genes, DNA hybridization, Archaea 16S rRNA and mcrA gene phylogenetic analyses. Total archaeal 16S rRNA abundance in sediments were higher in the low-salinity brackish sediments from HY (2-8 × 10(7) 16S rRNA gene copies cm(-3)) than the high-salinity marine sites from BR and AR (2 × 10(4)-2 × 10(7) and 4 × 10(6)-2 × 10(7) 16S rRNA gene copies cm(-3), respectively), although as a proportion of the total prokaryotes Archaea were higher at BR than at AR or HY. Phylogenetic analysis showed that members of the 'Bathyarchaeota' (MCG), Thaumarchaeota and methanogenic Euryarchaeota were the dominant groups of Archaea. The composition of Thaumarchaeota varied with salinity, as only 'marine' group I.1a was present in marine sediments (BR). Methanogen 16S rRNA genes from low-salinity sediments at HY were dominated by acetotrophic Methanosaeta and putatively hydrogentrophic Methanomicrobiales, whereas the marine site (BR) was dominated by mcrA genes belonging to methylotrophic Methanococcoides, versatile Methanosarcina and methanotrophic ANME-2a. Overall, the results indicate that salinity and associated factors play a role in controlling diversity and distribution of Archaea in estuarine sediments.

  16. Rendered-protein hydrolysates for microbial synthesis of cyanophycin biopolymer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyanophycin is a poly(arginyl-aspartate) biopolymer produced and stored intracellularly by bacteria. Cyanophycin has been proposed as a renewable replacement for petrochemical-based industrial products. An abundant source of amino acids and nitrogen such as in the form of protein hydrolysates is n...

  17. Biopolymers Containing Unnatural Building Blocks

    SciTech Connect

    Schultz, Peter G.

    2013-06-30

    Although the main chain structure of polymers has a profound effect on their materials properties, the side groups can also have dramatic effects on their properties including conductivity, liquid crystallinity, hydrophobicity, elasticity and biodegradability. Unfortunately control over the side chain structure of polymers remains a challenge – it is difficult to control the sequence of chain elongation when mixtures of monomers are polymerized, and postpolymerization side chain modification is made difficult by polymer effects on side chain reactivity. In contrast, the mRNA templated synthesis of polypeptides on the ribosome affords absolute control over the primary sequence of the twenty amino acid monomers. Moreover, the length of the biopolymer is precisely controlled as are sites of crosslinking. However, whereas synthetic polymers can be synthesized from monomers with a wide range of chemically defined structures, ribosomal biosynthesis is largely limited to the 20 canonical amino acids. For many applications in material sciences, additional building blocks would be desirable, for example, amino acids containing metallocene, photoactive, and halogenated side chains. To overcome this natural constraint we have developed a method that allows unnatural amino acids, beyond the common twenty, to be genetically encoded in response to nonsense or frameshift codons in bacteria, yeast and mammalian cells with high fidelity and good yields. Here we have developed methods that allow identical or distinct noncanonical amino acids to be incorporated at multiple sites in a polypeptide chain, potentially leading to a new class of templated biopolymers. We have also developed improved methods for genetically encoding unnatural amino acids. In addition, we have genetically encoded new amino acids with novel physical and chemical properties that allow selective modification of proteins with synthetic agents. Finally, we have evolved new metal-ion binding sites in proteins

  18. Enrichment of natural (15)N abundance during soil N losses under 20years of continuous cereal cropping.

    PubMed

    Jones, Andrew R; Dalal, Ram C

    2017-01-01

    It is generally accepted that the enrichment of natural (15)N abundance in soil over time is reflective of historic N cycling and loss, but this process in cropping soils is not yet clear. In this study, we identified an enrichment gradient of natural (15)N abundance during 20-year chronosequence of cereal cropping on Alfisols in southwest Queensland, Australia, that have no history of fertilisation. We demonstrate that the increase in soil (15)N abundance is explained by isotopic fractionation of (15)N during organic N mineralisation and nitrification, which lead to isotopically heavier ammonium retained in the soil and isotopically lighter soil nitrate taken up and removed by seasonal crops during harvest. Here we present a framework for natural (15)N isotopic fractionation co-occurring with N losses during long-term cultivation.

  19. Natural Abundance 17O Nuclear Magnetic Resonance and Computational Modeling Studies of Lithium Based Liquid Electrolytes

    SciTech Connect

    Deng, Xuchu; Hu, Mary Y.; Wei, Xiaoliang; Wang, Wei; Chen, Zhong; Liu, Jun; Hu, Jian Z.

    2015-07-01

    Natural abundance 17O NMR measurements were conducted on electrolyte solutions consisting of Li[CF3SO2NSO2CF3] (LiTFSI) dissolved in the solvents of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), and their mixtures at various concentrations. It was observed that 17O chemical shifts of solvent molecules change with the concentration of LiTFSI. The chemical shift displacements of carbonyl oxygen are evidently greater than those of ethereal oxygen, strongly indicating that Li+ ion is coordinated with carbonyl oxygen rather than ethereal oxygen. To understand the detailed molecular interaction, computational modeling of 17O chemical shifts was carried out on proposed solvation structures. By comparing the predicted chemical shifts with the experimental values, it is found that a Li+ ion is coordinated with four double bond oxygen atoms from EC, PC, EMC and TFSI- anion. In the case of excessive amount of solvents of EC, PC and EMC the Li+ coordinated solvent molecules are undergoing quick exchange with bulk solvent molecules, resulting in average 17O chemical shifts. Several kinds of solvation structures are identified, where the proportion of each structure in the liquid electrolytes investigated depends on the concentration of LiTFSI.

  20. 13C and 15N natural isotope abundance reflects breast cancer cell metabolism

    NASA Astrophysics Data System (ADS)

    Tea, Illa; Martineau, Estelle; Antheaume, Ingrid; Lalande, Julie; Mauve, Caroline; Gilard, Francoise; Barillé-Nion, Sophie; Blackburn, Anneke C.; Tcherkez, Guillaume

    2016-09-01

    Breast cancer is the most common cancer in women worldwide. Despite the information provided by anatomopathological assessment and molecular markers (such as receptor expression ER, PR, HER2), breast cancer therapies and prognostics depend on the metabolic properties of tumor cells. However, metabolomics have not provided a robust and congruent biomarker yet, likely because individual metabolite contents are insufficient to encapsulate all of the alterations in metabolic fluxes. Here, we took advantage of natural 13C and 15N isotope abundance to show there are isotopic differences between healthy and cancer biopsy tissues or between healthy and malignant cultured cell lines. Isotope mass balance further suggests that these differences are mostly related to lipid metabolism, anaplerosis and urea cycle, three pathways known to be impacted in malignant cells. Our results demonstrate that the isotope signature is a good descriptor of metabolism since it integrates modifications in C partitioning and N excretion altogether. Our present study is thus a starting point to possible clinical applications such as patient screening and biopsy characterization in every cancer that is associated with metabolic changes.

  1. Natural abundance 17O nuclear magnetic resonance and computational modeling studies of lithium based liquid electrolytes

    NASA Astrophysics Data System (ADS)

    Deng, Xuchu; Hu, Mary Y.; Wei, Xiaoliang; Wang, Wei; Chen, Zhong; Liu, Jun; Hu, Jian Zhi

    2015-07-01

    Natural abundance 17O NMR measurements were conducted on electrolyte solutions consisting of Li[CF3SO2NSO2CF3] (LiTFSI) dissolved in the solvents of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), and their mixtures at various concentrations. It was observed that 17O chemical shifts of solvent molecules change with the concentration of LiTFSI. The chemical shift displacements of carbonyl oxygen are evidently greater than those of ethereal oxygen, strongly indicating that Li+ ion is coordinated with carbonyl oxygen rather than ethereal oxygen. To understand the detailed molecular interaction, computational modeling of 17O chemical shifts was carried out on proposed solvation structures. By comparing the predicted chemical shifts with the experimental values, it is found that a Li+ ion is coordinated with four double bond oxygen atoms from EC, PC, EMC and TFSI- anion. In the case of excessive amount of solvents of EC, PC and EMC the Li+ coordinated solvent molecules are undergoing quick exchange with bulk solvent molecules, resulting in average 17O chemical shifts. Several kinds of solvation structures are identified, where the proportion of each structure in the liquid electrolytes investigated depends on the concentration of LiTFSI.

  2. 13C and 15N natural isotope abundance reflects breast cancer cell metabolism

    PubMed Central

    Tea, Illa; Martineau, Estelle; Antheaume, Ingrid; Lalande, Julie; Mauve, Caroline; Gilard, Francoise; Barillé-Nion, Sophie; Blackburn, Anneke C.; Tcherkez, Guillaume

    2016-01-01

    Breast cancer is the most common cancer in women worldwide. Despite the information provided by anatomopathological assessment and molecular markers (such as receptor expression ER, PR, HER2), breast cancer therapies and prognostics depend on the metabolic properties of tumor cells. However, metabolomics have not provided a robust and congruent biomarker yet, likely because individual metabolite contents are insufficient to encapsulate all of the alterations in metabolic fluxes. Here, we took advantage of natural 13C and 15N isotope abundance to show there are isotopic differences between healthy and cancer biopsy tissues or between healthy and malignant cultured cell lines. Isotope mass balance further suggests that these differences are mostly related to lipid metabolism, anaplerosis and urea cycle, three pathways known to be impacted in malignant cells. Our results demonstrate that the isotope signature is a good descriptor of metabolism since it integrates modifications in C partitioning and N excretion altogether. Our present study is thus a starting point to possible clinical applications such as patient screening and biopsy characterization in every cancer that is associated with metabolic changes. PMID:27678172

  3. Probing surface hydrogen bonding and dynamics by natural abundance, multidimensional, 17O DNP-NMR spectroscopy

    DOE PAGES

    Perras, Frederic A.; Chaudhary, Umesh; Slowing, Igor I.; ...

    2016-05-06

    Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy is increasingly being used as a tool for the atomic-level characterization of surface sites. DNP surface-enhanced SSNMR spectroscopy of materials has, however, been limited to studying relatively receptive nuclei, and the particularly rare 17O nuclide, which is of great interest for materials science, has not been utilized. We demonstrate that advanced 17O SSNMR experiments can be performed on surface species at natural isotopic abundance using DNP. We use 17O DNP surface-enhanced 2D SSNMR to measure 17O{1H} HETCOR spectra as well as dipolar oscillations on a series of thermally treatedmore » mesoporous silica nanoparticle samples having different pore diameters. These experiments allow for a nonintrusive and unambiguous characterization of hydrogen bonding and dynamics at the surface of the material; no other single experiment can give such details about the interactions at the surface. Lastly, our data show that, upon drying, strongly hydrogen-bonded surface silanols, whose motions are greatly restricted by the interaction when compared to lone silanols, are selectively dehydroxylated.« less

  4. Natural abundance deuterium and 18-oxygen effects on the precision of the doubly labeled water method

    NASA Technical Reports Server (NTRS)

    Horvitz, M. A.; Schoeller, D. A.

    2001-01-01

    The doubly labeled water method for measuring total energy expenditure is subject to error from natural variations in the background 2H and 18O in body water. There is disagreement as to whether the variations in background abundances of the two stable isotopes covary and what relative doses of 2H and 18O minimize the impact of variation on the precision of the method. We have performed two studies to investigate the amount and covariance of the background variations. These were a study of urine collected weekly from eight subjects who remained in the Madison, WI locale for 6 wk and frequent urine samples from 14 subjects during round-trip travel to a locale > or = 500 miles from Madison, WI. Background variation in excess of analytical error was detected in six of the eight nontravelers, and covariance was demonstrated in four subjects. Background variation was detected in all 14 travelers, and covariance was demonstrated in 11 subjects. The median slopes of the regression lines of delta2H vs. delta18O were 6 and 7, respectively. Modeling indicated that 2H and 18O doses yielding a 6:1 ratio of final enrichments should minimize this error introduced to the doubly labeled water method.

  5. Production of novel microbial biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microorganisms are well known to produce a wide variety of biobased polymers. These biopolymers have found a wide range of commercial uses, including food, feed, and consumer and industrial products. The production and possible uses of several novel biopolymers from both bacteria and fungi will be d...

  6. Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

    USGS Publications Warehouse

    Martin, B.A.; Saiki, M.K.

    2005-01-01

    We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray-Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinnaandPoecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes. ?? Springer 2005.

  7. (15)N natural abundance in plants of the Amazon River floodplain and potential atmospheric N2 fixation.

    PubMed

    Martinelli, L A; Victoria, R L; Trivelin, P C O; Devol, A H; Richey, J E

    1992-07-01

    The(15)N natural abundance values of various Amazon floodplain (várzea) plants was investigated. Samples of young leaf tissues were collected during three different periods of the river hydrography (low water, mid rising water and high water) and during one period in the Madeira River (high water). A large variation of(15)N abundance was observed, both among the different plant types and between the different flood stages. This variation probably, reflected, in part, the highly variable nature of the floodplain, sometimes dry and oxygenated and at other times inundated and anaerobic and, in part, changes in plant nitrogen metabolism. Comparison of the nitrogen isotopic composition of leguminous plants with that of non-leguminous plants showed that, on average, the(15)N abundance was lower in the legumes than non-legumes, suggesting active N-fixation. Also, the(15)N natural abundance in aquatic grasses of the generaPaspalum, was in general, lower than the(15)N abundance of aquatic grasses of the generaEchinochloa. As both of these grasses grow in the same general habitat, it appears thatPaspalum grasses may also be nitrogen fixers.

  8. A robust method for ammonium nitrogen isotopic analysis in freshwater and seawater at natural abundance levels

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Altabet, M. A.; Wu, T.; Hadas, O.

    2006-12-01

    Natural ammonium N isotopic abundance has been increasingly used in studies of marine and freshwater biogeochemistry. However, current methods are time-consuming, subject to interference from DON, and not reliable at low concentrations. Our new method for determining the δ15N of ammonium overcomes these difficulties by employing the oxidation of ammonium to nitrite followed by conversion of nitrite to nitrous oxide. In the first step, ammonium is quantitatively oxidized by hypobromite at pH~12. After the addition of sodium arsenite to consume excess hypobromite, yield is verified by colorimetric NO2-measurement using sulfanilamide and naphthyl ethylenediamine (NED). Nitrite is further reduced to N2O by a 1:1 sodium azide and acetic acid buffer solution using previously established procedures. Buffer concentration can be varied according to sample matrix to ensure that a reaction pH between 2 and 4 is reached. The product nitrous oxide is then isotopically analyzed using a continuous flow purge and cryogenic trap system coupled to an isotope ratio mass spectrometer. Reliable δ15N values (±0.31‰) are obtained over a concentration range of 0.5 μM to 20 μM using 20 ml volumes of either fresh or seawater samples. Reagent blanks are very low, about 0.05 μM. There is no interference from any of the nitrogen containing compounds tested except short chain aliphatic amino acid (i.e. glycine) which typically are not present at sufficiently high environmental concentrations to pose a problem.

  9. Natural abundance deuterium nuclear magnetic resonance spectroscopy: Study of the biosynthesis of monoterpenes

    SciTech Connect

    Leopold, M.F.

    1990-01-01

    Deuterium NMR spectroscopy at natural abundance (D NMR-na) is a new technique for exploring the biosynthesis of small molecules such as monoterpenes. The analysis of relative site-specific deuterium integration values is an effective means of measuring isotope effects, and examining the regio- and stereochemistry of biosynthetic reactions. The deuterium integration values of linalyl acetate and limonene isolated from the same source were consistent and showed that proton abstraction from the postulated {alpha}-terpinyl cation intermediate to form limonene is regioselective from the methyl derived from the Cs methyl of the precursor, geranyl diphosphate. This regiochemistry was observed in limonene samples from different sources and the measured primary kinetic isotope effect ranged from 0.25 to in excess of 100 (no deuterium was removed within experimental error). Various {alpha}- and {beta}-pinene samples were isolated and D NMR-na analysis showed evidence of isotopically sensitive partitioning of the pinylcation in the formation of these products. This spectral analysis supported published radiolabeling studies but did not require synthesis of substrates or enzyme purification. The formation of 3-carene occurs without isomerization of the double bond which was previously postulated. The olefinic deuterium of the bicyclic compound was traced to the depleted deuterium at C{sub 2} of isopentyl diphosphate by D NMR-na data and this supported unpublished radiolabeling studies. Study of irregular monoterpenes, chrysanthemyl acetate and lyratyl acetate, showed partitioning of dimethylallyl diphosphate (DMAPP) by chrysanthemyl cyclase. The {alpha}-secondary kinetic isotope effect of 1.06-1.12, obtained from relative deuterium integration values, suggested that S{sub N}1 ionization of one molecule of DMAPP is the first step in the condensation reaction.

  10. Critical evaluation of 13C natural abundance techniques to partition soil-surface CO2 efflux

    NASA Astrophysics Data System (ADS)

    Snell, H.; Midwood, A. J.; Robinson, D.

    2013-12-01

    Soil is the largest terrestrial store of carbon and the flux of CO2 from soils to the atmosphere is estimated at around 98 Pg (98 billion tonnes) of carbon per year. The CO2 efflux from the soil surface is derived from plant root and rhizosphere respiration (autotrophically fuelled) and microbial degradation of soil organic matter (heterotrophic respiration). Heterotrophic respiration is a key determinant of an ecosystem's long-term C balance, but one that is difficult to measure in the field. One approach involves partitioning the total soil-surface CO2 efflux between heterotrophic and autotrophic components; this can be done using differences in the natural abundance stable isotope ratios (δ13C) of autotrophic and heterotrophic CO2 as the end-members of a simple mixing model. In most natural, temperate ecosystems, current and historical vegetation cover (and therefore also plant-derived soil organic matter) is produced from C3 photosynthesis so the difference in δ13C between the autotrophic and heterotrophic CO2 sources is small. Successful partitioning therefore requires accurate and precise measurements of the δ13CO2 of the autotrophic and heterotrophic end-members (obtained by measuring the δ13CO2 of soil-free roots and root-free soil) and of total soil CO2 efflux. There is currently little consensus on the optimum measurement protocols. Here we systematically tested some of the most commonly used techniques to identify and minimise methodological errors. Using soil-surface chambers to sample total CO2 efflux and a cavity ring-down spectrometer to measure δ13CO2 in a partitioning study on a Scottish moorland, we found that: using soil-penetrating collars leads to a more depleted chamber measurement of total soil δ13CO2 as a result of severing roots and fungal hyphae or equilibrating with δ13CO2 at depth or both; root incubations provide an accurate estimate of in-situ root respired δ13CO2 provided they are sampled within one hour; the δ13CO2 from root

  11. The Determination of the Natural Abundance of the Isotopes of Chlorine: An Introductory Experiment in Mass Spectrometry.

    ERIC Educational Resources Information Center

    O'Malley, Rebecca M.

    1982-01-01

    Describes a laboratory experiment which introduces basic principles and experimental techniques of mass spectrometry for fourth year undergraduate (B.Sc.) students. Laboratory procedures, background information, and discussion of results are provided for the experiment in which the natural isotopic abundance of chlorine is determined. (Author/JN)

  12. Assessment of Label-Free Quantification in Discovery Proteomics and Impact of Technological Factors and Natural Variability of Protein Abundance.

    PubMed

    Al Shweiki, Mhd Rami; Mönchgesang, Susann; Majovsky, Petra; Thieme, Domenika; Trutschel, Diana; Hoehenwarter, Wolfgang

    2017-04-07

    We evaluated the state of label-free discovery proteomics focusing especially on technological contributions and contributions of naturally occurring differences in protein abundance to the intersample variability in protein abundance estimates in this highly peptide-centric technology. First, the performance of popular quantitative proteomics software, Proteome Discoverer, Scaffold, MaxQuant, and Progenesis QIP, was benchmarked using their default parameters and some modified settings. Beyond this, the intersample variability in protein abundance estimates was decomposed into variability introduced by the entire technology itself and variable protein amounts inherent to individual plants of the Arabidopsis thaliana Col-0 accession. The technical component was considerably higher than the biological intersample variability, suggesting an effect on the degree and validity of reported biological changes in protein abundance. Surprisingly, the biological variability, protein abundance estimates, and protein fold changes were recorded differently by the software used to quantify the proteins, warranting caution in the comparison of discovery proteomics results. As expected, ∼99% of the proteome was invariant in the isogenic plants in the absence of environmental factors; however, few proteins showed substantial quantitative variability. This naturally occurring variation between individual organisms can have an impact on the causality of reported protein fold changes.

  13. Heterogeneous Force Chains in Cellularized Biopolymer Network

    NASA Astrophysics Data System (ADS)

    Liang, Long; Jones, Christopher Allen Rucksack; Sun, Bo; Jiao, Yang

    Biopolymer Networks play an important role in coordinating and regulating collective cellular dynamics via a number of signaling pathways. Here, we investigate the mechanical response of a model biopolymer network due to the active contraction of embedded cells. Specifically, a graph (bond-node) model derived from confocal microscopy data is used to represent the network microstructure, and cell contraction is modeled by applying correlated displacements at specific nodes, representing the focal adhesion sites. A force-based stochastic relaxation method is employed to obtain force-balanced network under cell contraction. We find that the majority of the forces are carried by a small number of heterogeneous force chains emerged from the contracting cells. The force chains consist of fiber segments that either possess a high degree of alignment before cell contraction or are aligned due to the reorientation induced by cell contraction. Large fluctuations of the forces along different force chains are observed. Importantly, the decay of the forces along the force chains is significantly slower than the decay of radially averaged forces in the system, suggesting that the fibreous nature of biopolymer network structure could support long-range mechanical signaling between cells.

  14. Chemical modeling of acid-base properties of soluble biopolymers derived from municipal waste treatment materials.

    PubMed

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Marinos, Janeth Alicia Tafur; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo

    2015-02-04

    This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials.

  15. Abiotic origin of biopolymers

    NASA Technical Reports Server (NTRS)

    Oro, J.; Stephen-Sherwood, E.

    1976-01-01

    A variety of methods have been investigated in different laboratories for the polymerization of amino acids and nucleotides under abiotic conditions. They include (1) thermal polymerization; (2) direct polymerization of certain amino acid nitriles, amides, or esters; (3) polymerization using polyphosphate esters; (4) polymerization under aqueous or drying conditions at moderate temperatures using a variety of simple catalysts or condensing agents like cyanamide, dicyandiamide, or imidazole; and (5) polymerization under similar mild conditions but employing activated monomers or abiotically synthesized high-energy compounds such as adenosine 5'-triphosphate (ATP). The role and significance of these methods for the synthesis of oligopeptides and oligonucleotides under possible primitive-earth conditions is evaluated. It is concluded that the more recent approach involving chemical processes similar to those used by contemporary living organisms appears to offer a reasonable solution to the prebiotic synthesis of these biopolymers.

  16. A new method for the identification of the origin of natural products. Quantitative /sup 2/H NMR at the natural abundance level applied to the characterization of anetholes

    SciTech Connect

    Martin, G.J.; Martin, M.L.; Mabon, F.; Bricont, J.

    1982-05-05

    We have shown by high-field /sup 2/H NMR spectrometry at the natural abundance level that very spectacular differences exist in the interal distribution of /sup 2/H in organic molecules. This phenomenon has been exemplified in particular by the case of ethyl and vinyl derivatives. We show in this study of various anethole samples the potential of this new method as a very powerful tool for the characterization and identification of natural products from different origins.

  17. Interactions between natural-occurring landscape conditions and land use influencing the abundance of riverine smallmouth bass, micropterus dolomieu

    USGS Publications Warehouse

    Brewer, S.K.; Rabeni, C.F.

    2011-01-01

    This study examined how interactions between natural landscape features and land use influenced the abundance of smallmouth bass, Micropterus dolomieu, in Missouri, USA, streams. Stream segments were placed into one of four groups based on natural-occurring watershed characteristics (soil texture and soil permeability) predicted to relate to smallmouth bass abundance. Within each group, stream segments were assigned forest (n = 3), pasture (n = 3), or urban (n = 3) designations based on the percentages of land use within each watershed. Analyses of variance indicated smallmouth bass densities differed between land use and natural conditions. Decision tree models indicated abundance was highest in forested stream segments and lowest in urban stream segments, regardless of group designation. Land use explained the most variation in decision tree models, but in-channel features of temperature, flow, and sediment also contributed significantly. These results are unique and indicate the importance of natural-occurring watershed conditions in defining the potential of populations and how finer-scale filters interact with land use to further alter population potential. Smallmouth bass has differing vulnerabilities to land-use attributes, and the better the natural watershed conditions are for population success, the more resilient these populations will be when land conversion occurs.

  18. Is the Multicolored Asian Ladybeetle, Harmonia axyridis, the Most Abundant Natural Enemy to Aphids in Agroecosystems?

    PubMed Central

    Vandereycken, Axel; Durieux, Delphine; Joie, Emilie; Sloggett, John J.; Haubruge, Eric; Verheggen, François J.

    2013-01-01

    The multicolored Asian ladybeetle, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was introduced into Western Europe in the late 1990s. Since the late 2000s, this species has been commonly considered one of the most abundant aphid predators in most Western European countries. In spite of the large amount of research on H. axyridis, information concerning its relative abundance in agroecosystems is lacking. This study aims to evaluate the abundance of H. axyridis within the aphidophage community in four crops situated in southern Belgium: wheat, Triticum aestivum L. (Poales: Poaceae), corn, Zea mays, potato, Solanum tuberosum (Solanales: Solanaceae), and broad bean Vicia faba (Fabales: Fabaceae). In order to assess the species diversity, the collected data were analyzed by considering (1) the species richness and (2) the evenness according to the Shannon diversity index. Eleven aphidophages were observed in every inventoried agroecosystem, including five abundant species: three coccinellids, the seven-spotted ladybug, Coccinella septempunctata L. (Coleoptera: Coccinellidae), the 14-spotted Ladybird, Propylea quatuordecimpunctata, and H. axyridis; one hoverfly, the marmalade hoverfly, Episyrphus balteatus De Geer (Diptera: Syrphidae); and one lacewing, the common green lacewing, Chrysoperla carnea Stephens sensu lato (= s.l.) (Neuroptera: Chrysopidae). Harmonia axyridis has been observed to thrive, breed, and reproduce on the four studied crops. Harmonia axyridis is the most abundant predator of aphids in corn followed by C. septempunctata, which is the main aphid predator observed in the three other inventoried crops. In wheat and potato fields, H. axyridis occurs in low numbers compared to other aphidophage. These observations suggest that H. axyridis could be considered an invasive species of agrosystems, and that potato and wheat may intermittently act as refuges for other aphidophages vulnerable to intraguild predation by this invader. Harmonia axyridis

  19. Natural abundance 17O DNP two-dimensional and surface-enhanced NMR spectroscopy

    SciTech Connect

    Perras, Frédéric A.; Kobayashi, Takeshi; Pruski, Marek

    2015-06-22

    Due to its extremely low natural abundance and quadrupolar nature, the 17O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, the applicability of dynamic nuclear polarization (DNP), which leads to sensitivity enhancements of 2 orders of magnitude, to 17O is wrought with challenges due to the lack of spin diffusion and low polarization transfer efficiency from 1H. Here, we demonstrate new DNP-based measurements that extend 17O solid-state NMR beyond its current capabilities. The use of the PRESTO technique instead of conventional 1H–17O cross-polarization greatly improves the sensitivity and enables the facile measurement of undistorted line shapes and two-dimensional 1H–17O HETCOR NMR spectra as well as accurate internuclear distance measurements at natural abundance. This was applied for distinguishing hydrogen-bonded and lone 17O sites on the surface of silica gel; the one-dimensional spectrum of which could not be used to extract such detail. As a result, this greatly enhanced sensitivity has enabled, for the first time, the detection of surface hydroxyl sites on mesoporous silica at natural abundance, thereby extending the concept of DNP surface-enhanced NMR spectroscopy to the 17O nuclide.

  20. Assessment of the natural variation of low abundant metabolic proteins in soybean seeds using proteomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry, we investigated the distribution of the low abundant proteins that are involved in soybean seed development in four wild and twelve cultivated soybean genotypes. We found proteomic variation of these proteins within and...

  1. Flow and habitat effects on juvenile fish abundance in natural and altered flow regimes

    USGS Publications Warehouse

    Freeman, Mary C.; Bowen, Z.H.; Bovee, K.D.; Irwin, E.R.

    2001-01-01

    Conserving biological resources native to large river systems increasingly depends on how flow-regulated segments of these rivers are managed. Improving management will require a better understanding of linkages between river biota and temporal variability of flow and instream habitat. However, few studies have quantified responses of native fish populations to multiyear (>2 yr) patterns of hydrologic or habitat variability in flow-regulated systems. To provide these data, we quantified young-of-year (YOY) fish abundance during four years in relation to hydrologic and habitat variability in two segments of the Tallapoosa River in the southeastern United States. One segment had an unregulated flow regime, whereas the other was flow-regulated by a peak-load generating hydropower dam. We sampled fishes annually and explored how continuously recorded flow data and physical habitat simulation models (PHABSIM) for spring (April-June) and summer (July-August) preceding each sample explained fish abundances. Patterns of YOY abundance in relation to habitat availability (median area) and habitat persistence (longest period with habitat area continuously above the long-term median area) differed between unregulated and flow-regulated sites. At the unregulated site, YOY abundances were most frequently correlated with availability of shallow-slow habitat in summer (10 species) and persistence of shallow-slow and shallow-fast habitat in spring (nine species). Additionally, abundances were negatively correlated with 1-h maximum flow in summer (five species). At the flow-regulated site, YOY abundances were more frequently correlated with persistence of shallow-water habitats (four species in spring; six species in summer) than with habitat availability or magnitude of flow extremes. The associations of YOY with habitat persistence at the flow-regulated site corresponded to the effects of flow regulation on habitat patterns. Flow regulation reduced median flows during spring and

  2. Increased seawater temperature increases the abundance and alters the structure of natural Vibrio populations associated with the coral Pocillopora damicornis

    PubMed Central

    Tout, Jessica; Siboni, Nachshon; Messer, Lauren F.; Garren, Melissa; Stocker, Roman; Webster, Nicole S.; Ralph, Peter J.; Seymour, Justin R.

    2015-01-01

    Rising seawater temperature associated with global climate change is a significant threat to coral health and is linked to increasing coral disease and pathogen-related bleaching events. We performed heat stress experiments with the coral Pocillopora damicornis, where temperature was increased to 31°C, consistent with the 2–3°C predicted increase in summer sea surface maxima. 16S rRNA amplicon sequencing revealed a large shift in the composition of the bacterial community at 31°C, with a notable increase in Vibrio, including known coral pathogens. To investigate the dynamics of the naturally occurring Vibrio community, we performed quantitative PCR targeting (i) the whole Vibrio community and (ii) the coral pathogen Vibrio coralliilyticus. At 31°C, Vibrio abundance increased by 2–3 orders of magnitude and V. coralliilyticus abundance increased by four orders of magnitude. Using a Vibrio-specific amplicon sequencing assay, we further demonstrated that the community composition shifted dramatically as a consequence of heat stress, with significant increases in the relative abundance of known coral pathogens. Our findings provide quantitative evidence that the abundance of potential coral pathogens increases within natural communities of coral-associated microbes as a consequence of rising seawater temperature and highlight the potential negative impacts of anthropogenic climate change on coral reef ecosystems. PMID:26042096

  3. Biomedical Biopolymers, their Origin and Evolution in Biomedical Sciences: A Systematic Review

    PubMed Central

    Yadav, Harsh; Shah, Veena Gowri; Shah, Gaurav; Dhaka, Gaurav

    2015-01-01

    Biopolymers provide a plethora of applications in the pharmaceutical and medical applications. A material that can be used for biomedical applications like wound healing, drug delivery and tissue engineering should possess certain properties like biocompatibility, biodegradation to non-toxic products, low antigenicity, high bio-activity, processability to complicated shapes with appropriate porosity, ability to support cell growth and proliferation and appropriate mechanical properties, as well as maintaining mechanical strength. This paper reviews biodegradable biopolymers focusing on their potential in biomedical applications. Biopolymers most commonly used and most abundantly available have been described with focus on the properties relevant to biomedical importance. PMID:26501034

  4. Biomedical Biopolymers, their Origin and Evolution in Biomedical Sciences: A Systematic Review.

    PubMed

    Yadav, Preeti; Yadav, Harsh; Shah, Veena Gowri; Shah, Gaurav; Dhaka, Gaurav

    2015-09-01

    Biopolymers provide a plethora of applications in the pharmaceutical and medical applications. A material that can be used for biomedical applications like wound healing, drug delivery and tissue engineering should possess certain properties like biocompatibility, biodegradation to non-toxic products, low antigenicity, high bio-activity, processability to complicated shapes with appropriate porosity, ability to support cell growth and proliferation and appropriate mechanical properties, as well as maintaining mechanical strength. This paper reviews biodegradable biopolymers focusing on their potential in biomedical applications. Biopolymers most commonly used and most abundantly available have been described with focus on the properties relevant to biomedical importance.

  5. Sustainably Sourced, Thermally Resistant, Radiation Hard Biopolymer

    NASA Technical Reports Server (NTRS)

    Pugel, Diane

    2011-01-01

    This material represents a breakthrough in the production, manufacturing, and application of thermal protection system (TPS) materials and radiation shielding, as this represents the first effort to develop a non-metallic, non-ceramic, biomaterial-based, sustainable TPS with the capability to also act as radiation shielding. Until now, the standing philosophy for radiation shielding involved carrying the shielding at liftoff or utilizing onboard water sources. This shielding material could be grown onboard and applied as needed prior to different radiation landscapes (commonly seen during missions involving gravitational assists). The material is a bioplastic material. Bioplastics are any combination of a biopolymer and a plasticizer. In this case, the biopolymer is a starch-based material and a commonly accessible plasticizer. Starch molecules are composed of two major polymers: amylase and amylopectin. The biopolymer phenolic compounds are common to the ablative thermal protection system family of materials. With similar constituents come similar chemical ablation processes, with the potential to have comparable, if not better, ablation characteristics. It can also be used as a flame-resistant barrier for commercial applications in buildings, homes, cars, and heater firewall material. The biopolymer is observed to undergo chemical transformations (oxidative and structural degradation) at radiation doses that are 1,000 times the maximum dose of an unmanned mission (10-25 Mrad), indicating that it would be a viable candidate for robust radiation shielding. As a comparison, the total integrated radiation dose for a three-year manned mission to Mars is 0.1 krad, far below the radiation limit at which starch molecules degrade. For electron radiation, the biopolymer starches show minimal deterioration when exposed to energies greater than 180 keV. This flame-resistant, thermal-insulating material is non-hazardous and may be sustainably sourced. It poses no hazardous

  6. Optical hyperpolarization and inductive readout of 31P donor nuclei in natural abundance single crystal 29Si

    NASA Astrophysics Data System (ADS)

    Alexander, Thomas; Haas, Holger; Deshpande, Rahul; Gumann, Patryk; Cory, David

    2016-05-01

    We optically polarize and inductively detect 31P donor nuclei in single crystal silicon at high magnetic fields (6 . 7T). Samples include both natural abundance 29Si and an isotopically purified 28Si sample. We observe dipolar order in the 29Si nuclear spins through a spin-locking measurement. This provides a means of characterizing spin transport in the vicinity of the 31P donors.

  7. Nature's starships. I. Observed abundances and relative frequencies of amino acids in meteorites

    SciTech Connect

    Cobb, Alyssa K.; Pudritz, Ralph E. E-mail: pudritz@physics.mcmaster.ca

    2014-03-10

    The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 and CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. These two trends (total abundance and relative frequencies) can be used to constrain formation parameters of amino acids within planetesimals. Our organization of the data supports an onion shell model for the temperature structure of planetesimals. The least altered meteorites (type 3) and their amino acids originated near cooler surface regions. The most active amino acid synthesis likely took place at intermediate depths (type 2). The most altered materials (type 1) originated furthest toward parent body cores. This region is likely too hot to either favor amino acid synthesis or for amino acids to be retained after synthesis.

  8. Solid biopolymer electrolytes came from renewable biopolymer

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Zhang, Xingxiang; Qiao, Zhijun; Liu, Haihui

    2009-07-01

    Solid polymer electrolytes (SPEs) have attracted many attentions as solid state ionic conductors, because of their advantages such as high energy density, electrochemical stability, and easy processing. SPEs obtained from starch have attracted many attentions in recent years because of its abundant, renewable, low price, biodegradable and biocompatible. In addition, the efficient utilization of biodegradable polymers came from renewable sources is becoming increasingly important due to diminishing resources of fossil fuels as well as white pollution caused by undegradable plastics based on petroleum. So N, N-dimethylacetamide (DMAc) with certain concentration ranges of lithium chloride (LiCl) is used as plasticizers of cornstarch. Li+ can complexes with the carbonyl atoms of DMAc molecules to produce a macro-cation and leave the Cl- free to hydrogen bond with the hydroxyl or carbonyl of starch. This competitive hydrogen bond formation serves to disrupt the intra- and intermolecular hydrogen bonding existed in starch. Therefore, melt extrusion process conditions are used to prepare conductive thermoplastic starch (TPS). The improvements of LiCl concentration increase the water absorption and conductance of TPS. The conductance of TPS containing 0.14 mol LiCl achieve to 10-0.5 S cm-1 with 18 wt% water content.

  9. Proton conduction in biopolymer exopolysaccharide succinoglycan

    NASA Astrophysics Data System (ADS)

    Kweon, Jin Jung; Lee, Kyu Won; Kim, Hyojung; Lee, Cheol Eui; Jung, Seunho; Kwon, Chanho

    2014-07-01

    Protonic currents play a vital role in electrical signalling in living systems. It has been suggested that succinoglycan plays a specific role in alfalfa root nodule development, presumably acting as the signaling molecules. In this regard, charge transport and proton dynamics in the biopolymer exopolysaccharide succinoglycan have been studied by means of electrical measurements and nuclear magnetic resonance (NMR) spectroscopy. In particular, a dielectric dispersion in the system has revealed that the electrical conduction is protonic rather electronic. Besides, our laboratory- and rotating-frame 1H NMR measurements have elucidated the nature of the protonic conduction, activation of the protonic motion being associated with a glass transition.

  10. Proton conduction in biopolymer exopolysaccharide succinoglycan

    SciTech Connect

    Kweon, Jin Jung; Lee, Kyu Won; Kim, Hyojung; Lee, Cheol Eui; Jung, Seunho; Kwon, Chanho

    2014-07-07

    Protonic currents play a vital role in electrical signalling in living systems. It has been suggested that succinoglycan plays a specific role in alfalfa root nodule development, presumably acting as the signaling molecules. In this regard, charge transport and proton dynamics in the biopolymer exopolysaccharide succinoglycan have been studied by means of electrical measurements and nuclear magnetic resonance (NMR) spectroscopy. In particular, a dielectric dispersion in the system has revealed that the electrical conduction is protonic rather electronic. Besides, our laboratory- and rotating-frame {sup 1}H NMR measurements have elucidated the nature of the protonic conduction, activation of the protonic motion being associated with a glass transition.

  11. Biopolymers as transdermal drug delivery systems in dermatology therapy.

    PubMed

    Basavaraj, K H; Johnsy, George; Navya, M A; Rashmi, R; Siddaramaiah

    2010-01-01

    The skin is considered a complex organ for drug delivery because of its structure. Drug delivery systems are designed for the controlled release of drugs through the skin into the systemic circulation, maintaining consistent efficacy and reducing the dose of the drugs and their related side effects. Transdermal drug delivery represents one of the most rapidly advancing areas of novel drug delivery. The excellent impervious nature of the skin is the greatest challenge that must be overcome for successful drug delivery. Today, polymers have been proven to be successful for long-term drug delivery applications as no single polymer can satisfy all of the requirements. Biopolymers in the field of dermal application are rare and the mechanisms that affect skin absorption are almost unknown. Biopolymers are widely used as drug delivery systems, but as such the use of biopolymers as drug delivery systems in dermatologic therapy is still in progress. Commonly used biopolymers include hydrocolloids, alginates, hydrogels, polyurethane, collagen, poly(lactic-co-glycolic acid), chitosan, proteins and peptides, pectin, siRNAs, and hyaluronic acid. These new and exciting methods for drug delivery are already increasing the number and quality of dermal and transdermal therapies. This article reviews current research on biopolymers and focuses on their potential as drug carriers, particularly in relation to the dermatologic aspects of their use.

  12. Precision biopolymers from protein precursors for biomedical applications.

    PubMed

    Kuan, Seah Ling; Wu, Yuzhou; Weil, Tanja

    2013-03-12

    The synthesis of biohybrid materials with tailored functional properties represents a topic of emerging interest. Combining proteins as natural, macromolecular building blocks, and synthetic polymers opens access to giant brush-like biopolymers of high structural definition. The properties of these precision polypeptide copolymers can be tailored through various chemical modifications along their polypeptide backbone, which expands the repertoire of known protein-based materials to address biomedical applications. In this article, the synthetic strategies for the design of precision biopolymers from proteins through amino acid specific conjugation reagents are highlighted and the different functionalization strategies, their characterization, and applications are discussed.

  13. Nitrate dynamics in natural plants: insights based on the concentration and natural isotope abundances of tissue nitrate

    PubMed Central

    Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Liu, Cong-Qiang

    2014-01-01

    The dynamics of nitrate (NO−3), a major nitrogen (N) source for natural plants, has been studied mostly through experimental N addition, enzymatic assay, isotope labeling, and genetic expression. However, artificial N supply may not reasonably reflect the N strategies in natural plants because NO−3 uptake and reduction may vary with external N availability. Due to abrupt application and short operation time, field N addition, and isotopic labeling hinder the elucidation of in situ NO−3-use mechanisms. The concentration and natural isotopes of tissue NO−3 can offer insights into the plant NO−3 sources and dynamics in a natural context. Furthermore, they facilitate the exploration of plant NO−3 utilization and its interaction with N pollution and ecosystem N cycles without disturbing the N pools. The present study was conducted to review the application of the denitrifier method for concentration and isotope analyses of NO−3 in plants. Moreover, this study highlights the utility and advantages of these parameters in interpreting NO−3 sources and dynamics in natural plants. We summarize the major sources and reduction processes of NO−3 in plants, and discuss the implications of NO−3 concentration in plant tissues based on existing data. Particular emphasis was laid on the regulation of soil NO−3 and plant ecophysiological functions in interspecific and intra-plant NO−3 variations. We introduce N and O isotope systematics of NO−3 in plants and discuss the principles and feasibilities of using isotopic enrichment and fractionation factors; the correlation between concentration and isotopes (N and O isotopes: δ18O and Δ17O); and isotope mass-balance calculations to constrain sources and reduction of NO−3 in possible scenarios for natural plants are deliberated. Finally, we offer a preliminary framework of intraplant δ18O-NO−3 variation, and summarize the uncertainties in using tissue NO−3 parameters to interpret plant NO−3 utilization

  14. Nitrate dynamics in natural plants: insights based on the concentration and natural isotope abundances of tissue nitrate.

    PubMed

    Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Liu, Cong-Qiang

    2014-01-01

    The dynamics of nitrate (NO(-) 3), a major nitrogen (N) source for natural plants, has been studied mostly through experimental N addition, enzymatic assay, isotope labeling, and genetic expression. However, artificial N supply may not reasonably reflect the N strategies in natural plants because NO(-) 3 uptake and reduction may vary with external N availability. Due to abrupt application and short operation time, field N addition, and isotopic labeling hinder the elucidation of in situ NO(-) 3-use mechanisms. The concentration and natural isotopes of tissue NO(-) 3 can offer insights into the plant NO(-) 3 sources and dynamics in a natural context. Furthermore, they facilitate the exploration of plant NO(-) 3 utilization and its interaction with N pollution and ecosystem N cycles without disturbing the N pools. The present study was conducted to review the application of the denitrifier method for concentration and isotope analyses of NO(-) 3 in plants. Moreover, this study highlights the utility and advantages of these parameters in interpreting NO(-) 3 sources and dynamics in natural plants. We summarize the major sources and reduction processes of NO(-) 3 in plants, and discuss the implications of NO(-) 3 concentration in plant tissues based on existing data. Particular emphasis was laid on the regulation of soil NO(-) 3 and plant ecophysiological functions in interspecific and intra-plant NO(-) 3 variations. We introduce N and O isotope systematics of NO(-) 3 in plants and discuss the principles and feasibilities of using isotopic enrichment and fractionation factors; the correlation between concentration and isotopes (N and O isotopes: δ(18)O and Δ(17)O); and isotope mass-balance calculations to constrain sources and reduction of NO(-) 3 in possible scenarios for natural plants are deliberated. Finally, we offer a preliminary framework of intraplant δ(18)O-NO(-) 3 variation, and summarize the uncertainties in using tissue NO(-) 3 parameters to interpret

  15. Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes.

    PubMed

    Czekalski, Nadine; Sigdel, Radhika; Birtel, Julia; Matthews, Blake; Bürgmann, Helmut

    2015-08-01

    Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water.

  16. Identification of Biodegradation Pathways in a Multi-Process Phytoremediation System (MPPS) Using Natural Abundance 14C Analysis of PLFA

    NASA Astrophysics Data System (ADS)

    Cowie, B. R.; Greenberg, B. M.; Slater, G. F.

    2008-12-01

    Optimizing remediation of petroleum-contaminated soils requires thorough understanding of the mechanisms and pathways involved in a proposed remediation system. In many engineered and natural attenuation systems, multiple degradation pathways may contribute to observed contaminant mass losses. In this study, biodegradation in the soil microbial community was identified as a major pathway for petroleum hydrocarbon removal in a Multi-Process Phytoremediation System (MPPS) using natural abundance 14C analysis of Phospholipid Fatty Acids (PLFA). In contaminated soils, PLFA were depleted in Δ14C to less than -800‰, directly demonstrating microbial uptake and utilization of petroleum derived carbon (Δ14C = -992‰) during bioremediation. Mass balance indicated that more than 80% of microbial carbon was derived from petroleum hydrocarbons and a maximum of 20% was produced from metabolism of modern carbon sources. In contrast, in a nearby uncontaminated control soil, the microbial community maintained a nearly modern 14C signature, suggesting preferential degradation of more labile, recent carbon. Mass balance using δ13C and Δ14C of soil CO2 demonstrated that mineralization of petroleum carbon contributed 60-65% of soil CO2 at the contaminated site. The remainder was derived from atmospheric (27-30%) and decomposition of non- petroleum natural organic carbon (5-10%). The clean control exhibited substantially lower CO2 concentrations that were derived from atmospheric (55%) and natural organic carbon (45%) sources. This study highlights the value of using multiple carbon isotopes to identify degradation pathways in petroleum- contaminated soils undergoing phytoremediation and the power of natural abundance 14C to detect petroleum metabolism in natural microbial communities.

  17. Chemical composition and molecular structure of polysaccharide-protein biopolymer from Durio zibethinus seed: extraction and purification process

    PubMed Central

    2012-01-01

    Background The biological functions of natural biopolymers from plant sources depend on their chemical composition and molecular structure. In addition, the extraction and further processing conditions significantly influence the chemical and molecular structure of the plant biopolymer. The main objective of the present study was to characterize the chemical and molecular structure of a natural biopolymer from Durio zibethinus seed. A size-exclusion chromatography coupled to multi angle laser light-scattering (SEC-MALS) was applied to analyze the molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (Mw/Mn). Results The most abundant monosaccharide in the carbohydrate composition of durian seed gum were galactose (48.6-59.9%), glucose (37.1-45.1%), arabinose (0.58-3.41%), and xylose (0.3-3.21%). The predominant fatty acid of the lipid fraction from the durian seed gum were palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:2). The most abundant amino acids of durian seed gum were: leucine (30.9-37.3%), lysine (6.04-8.36%), aspartic acid (6.10-7.19%), glycine (6.07-7.42%), alanine (5.24-6.14%), glutamic acid (5.57-7.09%), valine (4.5-5.50%), proline (3.87-4.81%), serine (4.39-5.18%), threonine (3.44-6.50%), isoleucine (3.30-4.07%), and phenylalanine (3.11-9.04%). Conclusion The presence of essential amino acids in the chemical structure of durian seed gum reinforces its nutritional value. PMID:23062269

  18. Natural and synthetic poly(malic acid)-based derivates: a family of versatile biopolymers for the design of drug nanocarriers.

    PubMed

    Loyer, Pascal; Cammas-Marion, Sandrine

    2014-08-01

    The field of specific drug delivery is an expanding research domain. Besides the use of liposomes formed from various lipids, natural and synthetic polymers have been developed to prepare more efficient drug delivery systems either under macromolecular prodrugs or under particulate nanovectors. To ameliorate the biocompatibility of such nanocarriers, degradable natural or synthetic polymers have attracted the interest of many researchers. In this context, poly(malic acid) (PMLA) extracted from microorganisms or synthesized from malic or aspartic acid was used to prepare water-soluble drug carriers or nanoparticles. Within this review, both the preparation and the applications of PMLA derivatives are described emphasizing the in vitro and in vivo assays. The results obtained by several groups highlight the interest of such polyesters in the field of drug delivery.

  19. On the suppression of superconducting phase formation in YBCO materials by templated synthesis in the presence of a sulfated biopolymer

    NASA Astrophysics Data System (ADS)

    Smith, Elliott; Schnepp, Zoe; Wimbush, Stuart C.; Hall, Simon R.

    2008-11-01

    The use of biopolymers as templates to control superconductor crystallization is a recent phenomenon and is generating a lot of interest both from the superconductor community and in materials chemistry circles. This work represents a critical finding in the use of such biopolymers, in particular the contraindicatory nature of sulfur when attempting to affect a morphologically controlled synthesis. Synthesis of superconducting nanoparticles was attempted using carrageenan as a morphological template. Reactive sulfate groups on the biopolymer prevent this, producing instead significant quantities of barium sulfate nanotapes. By substituting the biopolymer for structurally analogous, non-sulfated agar, we show that superconducting nanoparticles could be successfully synthesized.

  20. New method for estimating bacterial cell abundances in natural samples by use of sublimation.

    PubMed

    Glavin, Daniel P; Cleaves, H James; Schubert, Michael; Aubrey, Andrew; Bada, Jeffrey L

    2004-10-01

    We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples, including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert, were heated to a temperature of 500 degrees C for several seconds under reduced pressure. The sublimate was collected on a cold finger, and the amount of adenine released from the samples was then determined by high-performance liquid chromatography with UV absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approximately 10(5) to 10(9) E. coli cell equivalents per gram. For most of these samples, the sublimation-based cell counts were in agreement with total bacterial counts obtained by traditional DAPI (4,6-diamidino-2-phenylindole) staining.

  1. New method for estimating bacterial cell abundances in natural samples by use of sublimation

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Cleaves, H. James; Schubert, Michael; Aubrey, Andrew; Bada, Jeffrey L.

    2004-01-01

    We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples, including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert, were heated to a temperature of 500 degrees C for several seconds under reduced pressure. The sublimate was collected on a cold finger, and the amount of adenine released from the samples was then determined by high-performance liquid chromatography with UV absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approximately 10(5) to 10(9) E. coli cell equivalents per gram. For most of these samples, the sublimation-based cell counts were in agreement with total bacterial counts obtained by traditional DAPI (4,6-diamidino-2-phenylindole) staining.

  2. Measuring tree root respiration using (13)C natural abundance: rooting medium matters.

    PubMed

    Cheng, Weixin; Fu, Shenglei; Susfalk, Richard B; Mitchell, Robert J

    2005-07-01

    Tree root respiration utilizes a major portion of the primary production in forests and is an important process in the global carbon cycle. Because of the lack of ecologically relevant methods, tree root respiration in situ is much less studied compared with above-ground processes such as photosynthesis and leaf respiration. This study introduces a new (13)C natural tracer method for measuring tree root respiration in situ. The method partitions tree root respiration from soil respiration in buried root chambers. Rooting media substantially influenced root respiration rates. Measured in three media, the fine root respiration rates of longleaf pine were 0.78, 0.27 and 0.18 mg CO(2) carbon mg(-1) root nitrogen d(-1) at 25 degrees C in the native soil, tallgrass prairie soil, and sand-vermiculite mixture, respectively. Compared with the root excision method, the root respiration rate of longleaf pine measured by the field chamber method was 18% higher when using the native soil as rooting medium, was similar in the prairie soil, but was 42% lower if in the sand-vermiculite medium. This natural tracer method allows the use of an appropriate rooting medium and is capable of measuring root respiration nondestructively in natural forest conditions.

  3. Inferring the nature of anthropogenic threats from long-term abundance records.

    PubMed

    Shoemaker, Kevin T; Akçakaya, H Resit

    2015-02-01

    Diagnosing the processes that threaten species persistence is critical for recovery planning and risk forecasting. Dominant threats are typically inferred by experts on the basis of a patchwork of informal methods. Transparent, quantitative diagnostic tools would contribute much-needed consistency, objectivity, and rigor to the process of diagnosing anthropogenic threats. Long-term census records, available for an increasingly large and diverse set of taxa, may exhibit characteristic signatures of specific threatening processes and thereby provide information for threat diagnosis. We developed a flexible Bayesian framework for diagnosing threats on the basis of long-term census records and diverse ancillary sources of information. We tested this framework with simulated data from artificial populations subjected to varying degrees of exploitation and habitat loss and several real-world abundance time series for which threatening processes are relatively well understood: bluefin tuna (Thunnus maccoyii) and Atlantic cod (Gadus morhua) (exploitation) and Red Grouse (Lagopus lagopus scotica) and Eurasian Skylark (Alauda arvensis) (habitat loss). Our method correctly identified the process driving population decline for over 90% of time series simulated under moderate to severe threat scenarios. Successful identification of threats approached 100% for severe exploitation and habitat loss scenarios. Our method identified threats less successfully when threatening processes were weak and when populations were simultaneously affected by multiple threats. Our method selected the presumed true threat model for all real-world case studies, although results were somewhat ambiguous in the case of the Eurasian Skylark. In the latter case, incorporation of an ancillary source of information (records of land-use change) increased the weight assigned to the presumed true model from 70% to 92%, illustrating the value of the proposed framework in bringing diverse sources of

  4. Determination of the natural abundance δ15N of taurine by gas chromatography-isotope ratio measurement mass spectrometry.

    PubMed

    Tea, Illa; Antheaume, Ingrid; Besnard, Jorick; Robins, Richard J

    2010-12-15

    The measurement of the nitrogen isotope ratio of taurine (2-aminoethanesulphonic acid) in biological samples has a large number of potential applications. Taurine is a small water-soluble molecule which is notoriously difficult to analyze due to its polarity and functionality. A method is described which allows the determination of the natural abundance δ(15)N values of taurine and structural analogues, such as 3-amino-1-propanesulphonic acid (APSA), by isotope ratio mass spectrometry interfaced to gas chromatography (GC-irm-MS). The one-step protocol exploits the simultaneous derivatization of both functionalities of these aminosulphonic acids by reaction with triethylorthoacetate (TEOA). Conditions have been established which ensure quantitative reaction thus avoiding any nitrogen isotope fractionation during derivatization and workup. The differences in the δ(15)N values of derivatized and non-derivatized taurine and APSA all fall within the working range of 0.4‰ (-0.02 to 0.39‰). When applied to four sources of taurine with various δ(15)N values, the method achieved excellent reproducibility and accuracy. The optimized method enables the determination of the natural abundance δ(15)N values of taurine over the concentration range 1.5-7.84 µmol.mL(-1) in samples of biological origin.

  5. Natural 15N- and 13C-abundance as indicators of forest nitrogen status and soil carbon dynamics

    SciTech Connect

    Garten Jr, Charles T; Hanson, Paul J; Todd Jr, Donald E; Lu, Benwhea Bonnie; Brice, Deanne Jane

    2007-09-01

    This book highlights new and emerging uses of stable isotope analysis in a variety of ecological disciplines. While the use of natural abundance isotopes in ecological research is now relatively standard, new techniques and ways of interpreting patterns are developing rapidly. The second edition of this book provides a thorough, up-to-date examination of these methods of research. As part of the Ecological Methods and Concepts series which provides the latest information on experimental techniques in ecology, this book looks at a wide range of techniques that use natural abundance isotopes to: {sm_bullet} follow whole ecosystem element cycling {sm_bullet} understand processes of soil organic matter formation {sm_bullet} follow the movement of water in whole watersheds {sm_bullet} understand the effects of pollution in both terrestrial and aquatic environments {sm_bullet} study extreme systems such as hydrothermal vents {sm_bullet}follow migrating organisms In each case, the book explains the background to the methodology, looks at the underlying principles and assumptions, and outlines the potential limitations and pitfalls. Stable Isotopes in Ecology and Environmental Science is an ideal resource for both ecologists who are new to isotopic analysis, and more experienced isotope ecologists interested in innovative techniques and pioneering new uses.

  6. Integrated Computational Protocol for Analyzing Quadrupolar Splittings from Natural Abundance Deuterium NMR Spectra in (Chiral) Oriented Media.

    PubMed

    Navarro-Vazquez, Armando; Berdagué, Philippe; Lesot, Philippe Georges Julien

    2017-03-03

    Despite its low natural abundance, deuterium NMR in weakly oriented (chiral) solvents gives easy access to deuterium residual quadrupolar couplings (2H-RQCs), which are formally equivalent to one-bond 1DCH (13C-1H)-RDCs for calculation of the Saupe order matrix, furnishing similar information to study molecular structure and orientational behavior. In addition, the quadrupolar interaction is one order of magnitude larger than the dipolar interaction, making 2H-RQC analysis much more sensitive tool for structural analysis. Subtle structural differences as well as tiny differences in the molecular alignment of different enantiomers in chiral aligning media can be detected. In order to promote this approach towards organic chemists interested in exploiting the analytical advantages of anisotropic, natural abundance deuterium NMR (NAD NMR), we describe a 2H-RQC/DFT-based integrated computational protocol for the evaluation of the order parameters of aligned solutes via singular value decomposition. Examples of 2H-RQC-assisted analysis of chiral and prochiral molecules dissolved in various polypeptide lyotropic chiral liquid crystals are reported. They illustrate the power of this hyphenated approach and in particular to understand the alignment processes and the role of molecular shape in the ordering mechanism through the determination of inter-tensor angles between alignment tensors and inertia tensors.

  7. A thalium-doped sodium iodide well counter for radioactive tracer applications with naturally-abundant 40K

    NASA Astrophysics Data System (ADS)

    Parker, Andrew J.; Boxall, Colin; Joyce, Malcolm J.; Schotanus, Paul

    2013-09-01

    The use of a thallium-doped sodium-iodide well-type scintillation detector for the assay of the low-activity radioisotope 40K, in open-source potassium chloride aqueous solutions, is described. The hazards, safety concerns and radiowaste generation associated with using open-source radioactive isotopes can present significant difficulties, the use of hot cells and escalated costs in radioanalytical laboratory research. A solution to this is the use of low-hazard alternatives that mimic the migration and dispersion characteristics of notable fission products (in this case 137Cs). The use of NaI(Tl) as a detection medium for naturally-abundant levels of 40K in a range of media is widespread, but the use of 40K as a radioactive tracer has not been reported. The use of such low-activity sources is often complicated by the ability to detect them efficiently. In this paper a scintillator detector designed to detect the naturally-abundant 40K present in potassium chloride in tracer applications is described. Examples of the use of potassium chloride as a tracer are given in the context of ion exchange and electrochemical migration studies, and comparisons in performance are drawn from literature with hyper pure germanium semiconductor detectors, which are more commonly utilised detectors in high-resolution counting applications.

  8. A New Method for Estimating Bacterial Abundances in Natural Samples using Sublimation

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Cleaves, H. James; Schubert, Michael; Aubrey, Andrew; Bada, Jeffrey L.

    2004-01-01

    We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert were heated to a temperature of 500 C for several seconds under reduced pressure. The sublimate was collected on a cold finger and the amount of adenine released from the samples then determined by high performance liquid chromatography (HPLC) with UV absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approx. l0(exp 5) to l0(exp 9) E. coli cell equivalents per gram. For most of these samples, the sublimation based cell counts were in agreement with total bacterial counts obtained by traditional DAPI staining. The simplicity and robustness of the sublimation technique compared to the DAPI staining method makes this approach particularly attractive for use by spacecraft instrumentation. NASA is currently planning to send a lander to Mars in 2009 in order to assess whether or not organic compounds, especially those that might be associated with life, are present in Martian surface samples. Based on our analyses of the Atacama Desert soil samples, several million bacterial cells per gam of Martian soil should be detectable using this sublimation technique.

  9. Locust bean gum: a versatile biopolymer.

    PubMed

    Prajapati, Vipul D; Jani, Girish K; Moradiya, Naresh G; Randeria, Narayan P; Nagar, Bhanu J

    2013-05-15

    Biopolymers or natural polymers are an attractive class of biodegradable polymers since they are derived from natural sources, easily available, relatively cheap and can be modified by suitable reagent. Locust bean gum is one of them that have a wide potentiality in drug formulations due to its extensive application as food additive and its recognized lack of toxicity. It can be tailored to suit its demands of applicants in both the pharmaceutical and biomedical areas. Locust bean gum has a wide application either in the field of novel drug delivery system as rate controlling excipients or in tissue engineering as scaffold formation. Through keen references of reported literature on locust bean gum, in this review, we have described critical aspects of locust bean gum, its manufacturing process, physicochemical properties and applications in various drug delivery systems.

  10. Rapid, storm-induced changes in the natural abundance of sup 15 N in a planktonic ecosystem, Chesapeake Bay, USA

    SciTech Connect

    Montoya, J.P.; McCarthy, J.J. ); Horrigan, S.G. )

    1991-12-01

    Samples of dissolved inorganic nitrogen (DIN), particulate nitrogen (PN), and two species of zooplankton were collected during two north-south transects of the Chesapeake Bay in the autumn of 1984 (27-28 September and 3-5 October). During the first transect, the natural abundance of {sup 15}N ({delta} {sup 15}N) in the major dissolved and planktonic pools of nitrogen suggested that the {delta}{sup 15}N of PN was largely determined by isotopic fractionation during uptake of NH{sub 4}{sup +} by phytoplankton. Averaged over the transect as a whole, the {delta}{sup 15}N of the herbivorous calanoid copepod Acartia tonsa was 4.1% higher than that of the PN, while the {delta}{sup 15}N of the carnivorous ctenophore Mnemiopsis leidyi was 6.4% higher than that of the PN. In the interval between the two transects, storm-induced mixing of the water column resulted in the injection of NH{sub 4}{sup +} into the surface layer of the bay. In combination with ancillary physical, chemical, and biological data, these changes in {delta}{sup 15}N provided estimates of the isotopic fractionation factor for NH{sub 4}{sup +} uptake by phytoplankton ({alpha} = 1.0065-1.0080) as well as the turnover time of nitrogen in Acartia tonsa (6.0-9.6 days). Despite the changes in {delta}{sup 15}N observed during this cruise, the relative distribution of {sup 15}N between trophic levels was preserved: during the second transect, the difference in {delta}{sup 15}N between Acartia tonsa and PN was 3.6%, and the difference in {delta}{sup 15}N between Mnemiopsis leidyi and PN was 7.3%. These results demonstrate that the natural abundance of {sup 15}N can change dramatically on a time scale of days, and that time-series studies of the natural abundance of {sup 15}N can be a useful complement to studies using tracer additions of {sup 15}N to document nitrogen transformations in planktonic ecosystems.

  11. Biotechnology: Unnatural biopolymers

    NASA Astrophysics Data System (ADS)

    Doi, Yoshiharu

    2002-12-01

    Genetically engineered bacteria could become polymer factories of the future. Bacteria can now turn non-natural chemicals into polythioesters - a new class of thermoplastic polymers hitherto inaccessible through chemical synthesis.

  12. Natural landscape and stream segment attributes influencing the distribution and relative abundance of riverine smallmouth bass in Missouri

    USGS Publications Warehouse

    Brewer, S.K.; Rabeni, C.F.; Sowa, S.P.; Annis, G.

    2007-01-01

    Protecting and restoring fish populations on a regional basis are most effective if the multiscale factors responsible for the relative quality of a fishery are known. We spatially linked Missouri's statewide historical fish collections to environmental features in a geographic information system, which was used as a basis for modeling the importance of landscape and stream segment features in supporting a population of smallmouth bass Micropterus dolomieu. Decision tree analyses were used to develop probability-based models to predict statewide occurrence and within-range relative abundances. We were able to identify the range of smallmouth bass throughout Missouri and the probability of occurrence within that range by using a few broad landscape variables: the percentage of coarse-textured soils in the watershed, watershed relief, and the percentage of soils with low permeability in the watershed. The within-range relative abundance model included both landscape and stream segment variables. As with the statewide probability of occurrence model, soil permeability was particularly significant. The predicted relative abundance of smallmouth bass in stream segments containing low percentages of permeable soils was further influenced by channel gradient, stream size, spring-flow volume, and local slope. Assessment of model accuracy with an independent data set showed good concordance. A conceptual framework involving naturally occurring factors that affect smallmouth bass potential is presented as a comparative model for assessing transferability to other geographic areas and for studying potential land use and biotic effects. We also identify the benefits, caveats, and data requirements necessary to improve predictions and promote ecological understanding. ?? Copyright by the American Fisheries Society 2007.

  13. Crosslinking biopolymers for biomedical applications.

    PubMed

    Reddy, Narendra; Reddy, Roopa; Jiang, Qiuran

    2015-06-01

    Biomaterials made from proteins, polysaccharides, and synthetic biopolymers are preferred but lack the mechanical properties and stability in aqueous environments necessary for medical applications. Crosslinking improves the properties of the biomaterials, but most crosslinkers either cause undesirable changes to the functionality of the biopolymers or result in cytotoxicity. Glutaraldehyde, the most widely used crosslinking agent, is difficult to handle and contradictory views have been presented on the cytotoxicity of glutaraldehyde-crosslinked materials. Recently, poly(carboxylic acids) that can crosslink in both dry and wet conditions have been shown to provide the desired improvements in tensile properties, increase in stability under aqueous conditions, and also promote cell attachment and proliferation. Green chemicals and newer crosslinking approaches are necessary to obtain biopolymeric materials with properties desired for medical applications.

  14. The natural abundance of 13C with different agricultural management by NIRS with fibre optic probe technology.

    PubMed

    Fuentes, Mariela; González-Martín, Inmaculada; Hernández-Hierro, Jose Miguel; Hidalgo, Claudia; Govaerts, Bram; Etchevers, Jorge; Sayre, Ken D; Dendooven, Luc

    2009-06-30

    In the present study the natural abundance of (13)C is quantified in agricultural soils in Mexico which have been submitted to different agronomic practices, zero and conventional tillage, retention of crop residues (with and without) and rotation of crops (wheat and maize) for 17 years, which have influenced the physical, chemical and biological characteristics of the soil. The natural abundance of C13 is quantified by near infrared spectra (NIRS) with a remote reflectance fibre optic probe, applying the probe directly to the soil samples. Discriminate partial least squares analysis of the near infrared spectra allowed to classify soils with and without residues, regardless of the type of tillage or rotation systems used with a prediction rate of 90% in the internal validation and 94% in the external validation. The NIRS calibration model using a modified partial least squares regression allowed to determine the delta(13)C in soils with or without residues, with multiple correlation coefficients 0.81 and standard error prediction 0.5 per thousand in soils with residues and 0.92 and 0.2 per thousand in soils without residues. The ratio performance deviation for the quantification of delta(13)C in soil was 2.5 in soil with residues and 3.8 without residues. This indicated that the model was adequate to determine the delta(13)C of unknown soils in the -16.2 per thousand to -20.4 per thousand range. The development of the NIR calibration permits analytic determinations of the values of delta(13)C in unknown agricultural soils in less time, employing a non-destructive method, by the application of the fibre optic probe of remote reflectance to the soil sample.

  15. Biopolymer Processing Using Ionic Liquids

    DTIC Science & Technology

    2014-08-07

    AFRL-OSR-VA-TR-2014-0181 (YIP-11) BIOPOLYMER PROCESSING USING IONIC LIQUIDS William Reichert UNIVERSITY OF SOUTH ALABAMA 08/07/2014 Final Report...3. DATES COVERED (From - To) May 2011-May 2014 4. TITLE AND SUBTITLE iopolymer Processing using Ionic Liquids for Feedstock Chemicals 5a...reaction and degradation products of the conversion of chitin and chitosan, and 3) investigate the effects of various reaction conditions, such as

  16. Biocompatibility of plasma nanostructured biopolymers

    NASA Astrophysics Data System (ADS)

    Slepičková Kasálková, N.; Slepička, P.; Bačáková, L.; Sajdl, P.; Švorčík, V.

    2013-07-01

    Many areas of medicine such as tissue engineering requires not only mastery of modification techniques but also thorough knowledge of the interaction of cells with solid state substrates. Plasma treatment can be used to effective modification, nanostructuring and therefore can significantly change properties of materials. In this work the biocompatibility of the plasma nanostructured biopolymers substrates was studied. Changes in surface chemical structure were studied by X-ray photoelectron spectroscopy (XPS). The morphology pristine and modified samples were determined using atomic force microscopy (AFM). The surface wettability was determined by goniometry from contact angle. Biocompatibility was determined by in vitro tests, the rat vascular smooth muscle cells (VSMCs) were cultivated on the pristine and plasma modified biopolymer substrates. Their adhesion, proliferation, spreading and homogeneous distribution on polymers was monitored. It was found that the plasma treatment leads to rapid decrease of contact angle for all samples. Contact angle decreased with increasing time of modification. XPS measurements showed that plasma treatment leads to changes in ratio of polar and non-polar groups. Plasma modification was accompanied by a change of surface morphology. Biological tests found that plasma treatment have positive effect on cells adhesion and proliferation cells and affects the size of cell's adhesion area. Changes in plasma power or in exposure time influences the number of adhered and proliferated cells and their distribution on biopolymer surface.

  17. The Impact of Invasive Earthworm Activity on Biopolymer Character of ýDecayed Litter ý

    NASA Astrophysics Data System (ADS)

    Filley, T.; Crow, S.; Johnston, C.; McCormick, M.; Szlavecz, K.

    2007-12-01

    Over the last 400-500 years invasive European earthworm populations have ýmoved steadily into North American forests either previously devoid of ýearthworms or that contained their own native populations. This has profound ýimpacts upon litter decay and soil organic matter dynamics. To determine the ýimpact of earthworm activity on the biopolymer and stable isotope chemistry of ýlitter residues and the nature of organic carbon moved to the soil profile we ýanalyzed tulip poplar leaves from a multi-year addition experiment in open ýsurface decay litter and litter bag decay experiments, as well as the associated ýsoils among forest plots that varied in non-native earthworm density and ýbiomass. The chemical alteration of biopolymers was tracked with FTIR ýspectroscopy, 13C-TMAH thermochemolysis, alkaline CuO extraction, and stable ýisotope mass spectrometry. Earthworm activity resulted in residues and soil ýparticulate organic matter depleted in cuticular aliphatic components and ýpolyphenols but highly enriched in ether-linked lignin with respect to initial litter ýmaterial. Decay in low earthworm abundance plots, as well as all experiments ýwith earthworm-excluding litter bags, resulted in enrichment in cutin aliphatics ýand only minor increases in ether linked lignin phenols which was also reflected ýin the soils below the amendments. Additionally, the stable carbon and nitrogen ýisotope composition of tulip poplar residues became isotopically distinct. The ýresults from litter bag decays were only reflective of the chemistry at sites with ývery low earthworm abundances. ý

  18. Determining the isotopic abundance of a labeled compound by mass spectrometry and how correcting for natural abundance distribution using analogous data from the unlabeled compound leads to a systematic error.

    PubMed

    Schenk, David J; Lockley, William J S; Elmore, Charles S; Hesk, Dave; Roberts, Drew

    2016-04-01

    When the isotopic abundance or specific activity of a labeled compound is determined by mass spectrometry (MS), it is necessary to correct the raw MS data to eliminate ion intensity contributions, which arise from the presence of heavy isotopes at natural abundance (e.g., a typical carbon compound contains ~1.1% (13) C per carbon atom). The most common approach is to employ a correction in which the mass-to-charge distribution of the corresponding unlabeled compound is used to subtract the natural abundance contributions from the raw mass-to-charge distribution pattern of the labeled compound. Following this correction, the residual intensities should be due to the presence of the newly introduced labeled atoms only. However, this will only be the case when the natural abundance mass isotopomer distribution of the unlabeled compound is the same as that of the labeled species. Although this may be a good approximation, it cannot be accurate in all cases. The implications of this approximation for the determination of isotopic abundance and specific activity have been examined in practice. Isotopically mixed stable-atom labeled valine batches were produced, and both these and [(14) C6 ]carbamazepine were analyzed by MS to determine the extent of the error introduced by the approach. Our studies revealed that significant errors are possible for small highly-labeled compounds, such as valine, under some circumstances. In the case with [(14) C6 ]carbamazepine, the errors introduced were minor but could be significant for (14) C-labeled compounds with particular isotopic distributions. This source of systematic error can be minimized, although not eliminated, by the selection of an appropriate isotopic correction pattern or by the use of a program that varies the natural abundance distribution throughout the correction.

  19. Dual production of biopolymers from bacteria.

    PubMed

    Sukan, Artun; Roy, Ipsita; Keshavarz, Tajalli

    2015-08-01

    Rapid depletion of natural resources with continued demands of an increasing population and high consumption rates of today's world will cause serious problems in the future. This, along with environmental concerns, has directed research towards finding alternatives in variety of sectors including sustainable and environmentally friendly consumer goods. Biopolymers of bacterial origin, with their vast range of applications, biodegradability and eco-friendly manufacturing processes, are one of the alternatives for a more sustainable future. However, the cost of their production is a drawback. Simultaneous production processes have always been an option for researchers in order to reduce cost, but the variable requirements of microorganisms to produce both different and valuable products are a hindering factor. This review will look at some examples and identify ideas towards developing a successful strategy for simultaneous production of bio-products.

  20. Female offspring desertion and male-only care increase with natural and experimental increase in food abundance.

    PubMed

    Eldegard, Katrine; Sonerud, Geir A

    2009-05-07

    In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a 1-year experimental study. Parents and offspring were fitted with radio-transmitters in order to reveal the parental care strategy (i.e. care or desert) of individual parents, and to keep track of the broods post-fledging. We found that 70 per cent of the females from non-experimental nests deserted, while their partner continued to care for their joint offspring alone. Desertion rate was positively related to natural prey population densities and body reserves of the male partner. In response to food supplementation, a larger proportion of the females deserted, and females deserted the offspring at an earlier age. Offspring survival during the post-fledging period tended to be lower in deserted than in non-deserted broods. We argue that the most important benefit of deserting may be remating (sequential polyandry).

  1. MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

    SciTech Connect

    Leschine, Susan

    2009-10-31

    Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate that the chitinase and cellulase systems of this bacterium are distinct in terms of the proteins involved and the regulation of their production. 4. Characterization of the chitinase system of C. uda. A 70,000-Mr endochitinase, designated ChiA, was purified from C. uda culture supernatant fluids and characterized. 5. Analysis of chiA, which codes for the major enzymatic component of the chitinase system of C. uda. The gene encoding the endochitinase ChiA in C. uda was cloned, its complete nucleotide sequence was determined and its implications were investigated. 6. Formation of biofilms by C. uda on cellulose and chitin. Microscopic observations indicated that, under conditions of nitrogen limitation, C. uda cells grew as a biofilm attached tightly to the surface of cellulose or chitin. 7. Development of tools for a genetic approach to studies of cellulose fermentation by cellulolytic clostridia. We have explored the potential of various techniques, and obtained evidence indicating that Tn916 mutagenesis may be particularly effective in this regard. As part of this research, we identified the presence of a plasmid in one strain, which was cloned, sequenced, and analyzed for its utility in the development of vectors for genetic studies. 8. Effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes. We determined that humic substances play an important role in the anaerobic cellulose decomposition and in the physiology of cellulose-fermenting soil bacteria. 9. Nitrogenases of cellulolytic clostridia. We described a nitrogenase gene from a cellulolytic clostridium and presented evidence, based on sequence analyses and conserved gene order, for lateral gene transfer between this bacterium and a methanogenic archaeon. 10. Characterization of Clostridium hungatei, a new N2-fixing cellulolytic species isolated from a methanogenic consortium from soil. 11. Understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. We discovered that C. papyrosolvens produces a multiprotein, multicomplex cellulase-xylanase enzyme system that hydrolyzes crystalline cellulose, and we have described this system in detail.

  2. Effects of weed cover composition on insect pest and natural enemy abundance in a field of Dracaena marginata (Asparagales: Asparagaceae) in Costa Rica.

    PubMed

    Sadof, Clifford S; Linkimer, Mildred; Hidalgo, Eduardo; Casanoves, Fernando; Gibson, Kevin; Benjamin, Tamara J

    2014-04-01

    Weeds and their influence on pest and natural enemy populations were studied on a commercial ornamental farm during 2009 in the Atlantic Zone of Costa Rica. A baseline survey of the entire production plot was conducted in February, along a 5 by 5 m grid to characterize and map initial weed communities of plants, cicadellids, katydids, and armored scales. In total, 50 plant species from 21 families were found. Seven weed treatments were established to determine how weed manipulations would affect communities of our targeted pests and natural enemies. These treatments were selected based on reported effects of specific weed cover on herbivorous insects and natural enemies, or by their use by growers as a cover crop. Treatments ranged from weed-free to being completely covered with endemic species of weeds. Although some weed treatments changed pest abundances, responses differed among arthropod pests, with the strongest effects observed for Caldwelliola and Empoasca leafhoppers. Removal of all weeds increased the abundance of Empoasca, whereas leaving mostly cyperacaeous weeds increased the abundance of Caldwelliola. Weed manipulations had no effect on the abundance of katydid and scale populations. No weed treatment reduced the abundance of all three of the target pests. Differential responses of the two leafhopper species to the same weed treatments support hypotheses, suggesting that noncrop plants can alter the abundance of pests through their effects on arthropod host finding and acceptance, as well as their impacts on natural enemies.

  3. Investigation of biopolymer networks by means of AFM

    NASA Astrophysics Data System (ADS)

    Keresztes, Z.; Rigó, T.; Telegdi, J.; Kálmán, E.

    Natural hydrogel alginate was investigated by means of atomic force microscopy (AFM) to gain microscale information on the morphological and rheological properties of the biopolymer network cross-linked by various cations. Local rheological properties of the gels measured by force spectroscopy gave correlation between increasing ion selectivity and increasing polymer elasticity. Adhesive forces acting between the surface of the gel and the probe, and also the intrinsic rheological properties of bulk polymers affect the microscopical image formation.

  4. Interaction between polymer constituents and the structure of biopolymers

    NASA Technical Reports Server (NTRS)

    Rein, R.

    1974-01-01

    The paper reviews the current status of methods for calculating intermolecular interactions between biopolymer units. The nature of forces contributing to the various domains of intermolecular separations is investigated, and various approximations applicable in the respective regions are examined. The predictive value of current theory is tested by establishing a connection with macroscopic properties and comparing the theoretical predicted values with those derived from experimental data. This has led to the introduction of a statistical model describing DNA.

  5. Abundance and diversity of CO2-fixing bacteria in grassland soils close to natural carbon dioxide springs.

    PubMed

    Videmsek, Urska; Hagn, Alexandra; Suhadolc, Marjetka; Radl, Viviane; Knicker, Heike; Schloter, Michael; Vodnik, Dominik

    2009-07-01

    Gaseous conditions at natural CO2 springs (mofettes) affect many processes in these unique ecosystems. While the response of plants to extreme and fluctuating CO2 concentrations ([CO2]) is relatively well documented, little is known on microbial life in mofette soil. Therefore, it was the aim of this study to investigate the abundance and diversity of CO2-fixing bacteria in grassland soils in different distances to a natural carbon dioxide spring. Samples of the same soil type were collected from the Stavesinci mofette, a natural CO2 spring which is known for very pure CO2 emissions, at different distances from the CO2 releasing vents, at locations that clearly differed in soil CO2 efflux (from 12.5 to over 200 micromol CO2 m(-2) s(-1) yearly average). Bulk and rhizospheric soil samples were included into analyses. The microbial response was followed by a molecular analysis of cbbL genes, encoding for the large subunit of RubisCO, a carboxylase which is of crucial importance for C assimilation in chemolitoautotrophic microbes. In all samples analyzed, the "red-like" type of cbbL genes could be detected. In contrast, the "green-like" type of cbbL could not be measured by the applied technique. Surprisingly, a reduction of "red-like" cbbL genes copies was observed in bulk soil and rhizosphere samples from the sites with the highest CO2 concentrations. Furthermore, the diversity pattern of "red-like" cbbL genes changed depending on the CO(2) regime. This indicates that only a part of the autotrophic CO2-fixing microbes could adapt to the very high CO2 concentrations and adverse life conditions that are governed by mofette gaseous regime.

  6. Supramolecular self-assembly of biopolymers with carbon nanotubes for biomimetic and bio-inspired sensing and actuation.

    PubMed

    Lu, Luhua; Chen, Wei

    2011-06-01

    Biopolymers are important natural multifunctional macromolecules for biomimetic and bio-inspired advanced functional material design. They are not only simple dispersants for carbon nanotube stabilization as they have been found to have specific interactions with carbon nanotubes. Their molecular activity, orientation and crystallization are influenced by the CNTs, which endow their composites with a variety of novel sensing and actuation performances. This review focuses on the progress in supramolecular self-assembly of biopolymers with carbon nanotubes, and their advances in sensing and actuation. To promote the development of advanced biopolymer/CNT functional materials, new electromechanical characteristics of biopolymer/CNT composites are discussed in detail based on the relationship between the microscopic biopolymer structures and the macroscopic composite properties.

  7. [Magnetic nanoparticles and intracellular delivery of biopolymers].

    PubMed

    Kornev, A A; Dubina, M V

    2014-03-01

    The basic methods of intracellular delivery of biopolymers are present in this review. The structure and synthesis of magnetic nanoparticles, their stabilizing surfactants are described. The examples of the interaction of nanoparticles with biopolymers such as nucleic acids and proteins are considered. The final part of the review is devoted to problems physiology and biocompatibility of magnetic nanoparticles.

  8. Factors Driving the Abundance of Ixodes ricinus Ticks and the Prevalence of Zoonotic I. ricinus-Borne Pathogens in Natural Foci

    PubMed Central

    Fernández-de-Mera, Isabel G.; Acevedo, Pelayo; Gortázar, Christian; de la Fuente, José

    2012-01-01

    Environmental factors may drive tick ecology and therefore tick-borne pathogen (TBP) epidemiology, which determines the risk to animals and humans of becoming infected by TBPs. For this reason, the aim of this study was to analyze the influence of environmental factors on the abundance of immature-stage Ixodes ricinus ticks and on the prevalence of two zoonotic I. ricinus-borne pathogens in natural foci of endemicity. I. ricinus abundance was measured at nine sites in the northern Iberian Peninsula by dragging the vegetation with a cotton flannelette, and ungulate abundance was measured by means of dung counts. In addition to ungulate abundance, data on variables related to spatial location, climate, and soil were gathered from the study sites. I. ricinus adults, nymphs, and larvae were collected from the vegetation, and a representative subsample of I. ricinus nymphs from each study site was analyzed by PCR for the detection of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum DNA. Mean prevalences of these pathogens were 4.0% ± 1.8% and 20.5% ± 3.7%, respectively. Statistical analyses confirmed the influence of spatial factors, climate, and ungulate abundance on I. ricinus larva abundance, while nymph abundance was related only to climate. Interestingly, cattle abundance rather than deer abundance was the main driver of B. burgdorferi sensu lato and A. phagocytophilum prevalence in I. ricinus nymphs in the study sites, where both domestic and wild ungulates coexist. The increasing abundance of cattle seems to increase the risk of other hosts becoming infected by A. phagocytophilum, while reducing the risk of being infected by B. burgdorferi sensu lato. Controlling ticks in cattle in areas where they coexist with wild ungulates would be more effective for TBP control than reducing ungulate abundance. PMID:22286986

  9. Shape-memory biopolymers based on β-sheet structures of polyalanine segments inspired by spider silks.

    PubMed

    Huang, Huahua; Hu, Jinlian; Zhu, Yong

    2013-02-01

    The molecular structural design learned from natural materials enables synthetic polymers with desirable and unique features to be fabricated. Inspired by spider silks, short-chain polyalanine (PA) is introduced into multiblock biopolymers with poly(ε-caprolactone) segments via a coupling reaction. As a result, PA segments in biopolymers form similar β-sheet crystals to that of natural spidroins. These new biopolymers are found to exhibit nearly complete shape recovery and high shape fixity, along with significantly improved thermal stability due to the strong β-sheet structures as netpoints. This work provides new insight for the design of novel shape-memory polymers with potential use in biomedical applications.

  10. Abundance of non-native crabs in intertidal habitats of New England with natural and artificial structure

    PubMed Central

    Lovely, Christina M.; Judge, Michael L.

    2015-01-01

    Marine habitats containing complex physical structure (e.g., crevices) can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock) and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m2 with 62 mm2 mesh openings). The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width) whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1–15 mm carapace width), and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m−2 [mean ± S.D.]) and fewest in bags without shells (4.9 ± 3.7 m−2). Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks). The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations. PMID:26401456

  11. Abundance of non-native crabs in intertidal habitats of New England with natural and artificial structure.

    PubMed

    Lovely, Christina M; O'Connor, Nancy J; Judge, Michael L

    2015-01-01

    Marine habitats containing complex physical structure (e.g., crevices) can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock) and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m(2) with 62 mm(2) mesh openings). The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width) whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1-15 mm carapace width), and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m(-2) [mean ± S.D.]) and fewest in bags without shells (4.9 ± 3.7 m(-2)). Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks). The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations.

  12. Natural Abundance 43Ca NMR as a Tool for Exploring Calcium Biomineralization: Renal Stone Formation and Growth

    SciTech Connect

    Bowers, Geoffrey M.; Kirkpatrick, Robert J.

    2011-12-07

    Renal stone diseases are a global health issue with little effective therapeutic recourse aside from surgery and shock-wave lithotripsy, primarily because the fundamental chemical mechanisms behind calcium biomineralization are poorly understood. In this work, we show that natural abundance 43Ca NMR at 21.1 T is an effective means to probe the molecular-level Ca2+ structure in oxalate-based kidney stones. We find that the 43Ca NMR resonance of an authentic oxalate-based kidney stone cannot be explained by a single pure phase of any common Ca2+-bearing stone mineral. Combined with XRD results, our findings suggest an altered calcium oxalate monohydrate-like Ca2+ coordination environment for some fraction of Ca2+ in our sample. The evidence is consistent with existing literature hypothesizing that nonoxalate organic material interacts directly with Ca2+ at stone surfaces and is the primary driver of renal stone aggregation and growth. Our findings show that 43Ca NMR spectroscopy may provide unique and crucial insight into the fundamental chemistry of kidney stone formation, growth, and the role organic molecules play in these processes.

  13. Symbiotic nitrogen fixation in a tropical rainforest: 15N natural abundance measurements supported by experimental isotopic enrichment.

    PubMed

    Pons, Thijs L; Perreijn, Kristel; van Kessel, Chris; Werger, Marinus J A

    2007-01-01

    * Leguminous trees are very common in the tropical rainforests of Guyana. Here, species-specific differences in N(2) fixation capability among nodulating legumes growing on different soils and a possible limitation of N(2) fixation by a relatively high nitrogen (N) and low phosphorus (P) availability in the forest were investigated. * Leaves of 17 nodulating species and 17 non-nodulating reference trees were sampled and their delta(15)N values measured. Estimates of N(2) fixation rates were calculated using the (15)N natural abundance method. Pot experiments were conducted on the effect of N and P availability on N(2) fixation using the (15)N-enriched isotope dilution method. * Nine species showed estimates of > 33% leaf N derived from N(2) fixation, while the others had low or undetectable N(2) fixation rates. High N and low P availability reduced N(2) fixation substantially. * The results suggest that a high N and low P availability in the forest limit N(2) fixation. At the forest ecosystem level, N(2) fixation was estimated at c. 6% of total N uptake by the tree community. We conclude that symbiotic N(2) fixation plays an important role in maintaining high amounts of soil available N in undisturbed forest.

  14. Molecular characterization of dissolved organic matter in glacial ice: coupling natural abundance 1H NMR and fluorescence spectroscopy.

    PubMed

    Pautler, Brent G; Woods, Gwen C; Dubnick, Ashley; Simpson, André J; Sharp, Martin J; Fitzsimons, Sean J; Simpson, Myrna J

    2012-04-03

    Glaciers and ice sheets are the second largest freshwater reservoir in the global hydrologic cycle, and the onset of global climate warming has necessitated an assessment of their contributions to sea-level rise and the potential release of nutrients to nearby aquatic environments. In particular, the release of dissolved organic matter (DOM) from glacier melt could stimulate microbial activity in both glacial ecosystems and adjacent watersheds, but this would largely depend on the composition of the material released. Using fluorescence and (1)H NMR spectroscopy, we characterize DOM at its natural abundance in unaltered samples from a number of glaciers that differ in geographic location, thermal regime, and sample depth. Parallel factor analysis (PARAFAC) modeling of DOM fluorophores identifies components in the ice that are predominantly proteinaceous in character, while (1)H NMR spectroscopy reveals a mixture of small molecules that likely originate from native microbes. Spectrofluorescence also reveals a terrestrial contribution that was below the detection limits of NMR; however, (1)H nuclei from levoglucosan was identified in Arctic glacier ice samples. This study suggests that the bulk of the DOM from these glaciers is a mixture of biologically labile molecules derived from microbes.

  15. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    SciTech Connect

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; Singappuli-Arachchige, D.; Slowing, I. I.; Pruski, M.

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimension without resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.

  16. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    DOE PAGES

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; ...

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimensionmore » without resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.« less

  17. Probing surface hydrogen bonding and dynamics by natural abundance, multidimensional, 17O DNP-NMR spectroscopy

    SciTech Connect

    Perras, Frederic A.; Chaudhary, Umesh; Slowing, Igor I.; Pruski, Marek

    2016-05-06

    Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy is increasingly being used as a tool for the atomic-level characterization of surface sites. DNP surface-enhanced SSNMR spectroscopy of materials has, however, been limited to studying relatively receptive nuclei, and the particularly rare 17O nuclide, which is of great interest for materials science, has not been utilized. We demonstrate that advanced 17O SSNMR experiments can be performed on surface species at natural isotopic abundance using DNP. We use 17O DNP surface-enhanced 2D SSNMR to measure 17O{1H} HETCOR spectra as well as dipolar oscillations on a series of thermally treated mesoporous silica nanoparticle samples having different pore diameters. These experiments allow for a nonintrusive and unambiguous characterization of hydrogen bonding and dynamics at the surface of the material; no other single experiment can give such details about the interactions at the surface. Lastly, our data show that, upon drying, strongly hydrogen-bonded surface silanols, whose motions are greatly restricted by the interaction when compared to lone silanols, are selectively dehydroxylated.

  18. Non-biodegradable biopolymers from renewable resources: perspectives and impacts.

    PubMed

    Steinbüchel, Alexander

    2005-12-01

    In recent years the biotechnological production of bulk biopolymers has focused on the synthesis of biodegradable polymers to replace their non-biodegradable counterparts derived from fossil resources. Examples include polyhydroxyalkanoates and polylactic acid, which act as substitutes for polyolefins. By contrast, the biotechnological production of non-biodegradable polymers from renewable resources has so far been scarcely considered, probably because this idea contradicts the paradigm that all natural compounds are biodegradable. Polythioesters, which were recently described as new biopolymers, do not follow this paradigm because although they are produced by bacteria, they are persistent to microbial degradation. Mankind has a need for both non-biodegradable and biodegradable polymers and methods to produce them from renewable resources will be of great value.

  19. Technology Transfer of Biopolymer Soil Amendment for Rapid Revegetation and Erosion Control at Fort A. P. Hill, Virginia

    DTIC Science & Technology

    2016-05-01

    consisting of a polysaccharide polymeric material, a natural product of plant/soil rhyzobial microbial activity, was demonstrated to enhance site...its prolific production of a gel-like, extracellular polymeric substance (EPS), a biopolymer (Gil-Serrano et al. 1990). The natural functions of the...TN) evaluates application of this biopolymer to a highly disturbed and erodible soil. BACKGROUND: Most training areas present soil erosion

  20. Estimation of biological nitrogen fixation by black locust in short-rotation forests using natural 15N abundance method

    NASA Astrophysics Data System (ADS)

    Veste, M.; Böhm, C.; Quinckenstein, A.; Freese, D.

    2012-04-01

    The importance of short rotation forests and agroforestry systems for woody biomass production for bioenergy will increase in Central Europe within the next decades. In this context, black locust (Robinia pseudoacacia) has a high growth potential especially at marginal, drought-susceptible sites such as occur in Brandenburg State (Eastern Germany). As a pioneer tree species black locust grows under a wide range of site conditions. The native range of black locust in Northern America is classified by a humid to sub-humid climate with a mean annual precipitation of 1020 to 1830 mm. In Central and Eastern Europe, this species is cultivated in a more continental climate with an annual precipitation often below 600 mm. Therefore, black locust is known to be relatively drought tolerant compared to other temperate, deciduous tree species. Because of its N2-fixation ability black locust plays generally an important role for the improvement of soil fertility. This effect is of particular interest at marginal sites in the post-mining landscapes. In order to estimate the N2-fixation potential of black locust at marginal sites leaf samples were taken from black locust trees in short rotation plantations planted between 1995 and 2007 in post-mining sites south of Cottbus (Brandenburg, NE Germany). The variation of the natural 15N abundance was measured to evaluate the biological nitrogen fixation. The nitrogen derived from the atmosphere can be calculated using a two-pool model from the quotient of the natural 15N abundances of the N2-fixing plant and the plant available soil N. Because representatively determining the plant available soil N is difficult, a non-N2-fixing reference plant growing at the same site with a similar root system and temporal N uptake pattern to the N2-fixing plant is often used. In our case we used red oak (Quercus rubra) as a reference. The average nitrogen content in the leaves of black locust ranged from 3.1% (C/N 14.8) in 15 years old trees to 3

  1. Natural-abundance stable carbon isotopes of small-subunit ribosomal RNA (SSU rRNA) from Guaymas Basin (Mexico)

    NASA Astrophysics Data System (ADS)

    MacGregor, B. J.; Mendlovitz, H.; Albert, D.; Teske, A. P.

    2012-12-01

    Small-subunit ribosomal RNA (SSU rRNA) is a phylogenetically informative molecule found in all species. Because it is poorly preserved in most environments, it is a useful marker for active microbial populations. We are using the natural-abundance stable carbon isotopic composition of specific microbial groups to help identify the carbon substrates contributing to microbial biomass in a variety of marine environments. At Guaymas Basin, hydrothermal fluids interact with abundant sedimentary organic carbon to produce natural gas and petroleum. Where this reaches the sediment surface, it can support dense patches of seafloor life, including Beggiatoa mats. We report here on the stable carbon isotopic composition of SSU rRNA from a Beggiatoa mat transect, a cold background site, a warm site with high oil concentration, and a second Beggiatoa mat. The central part of the transect mat overlay the steepest temperature gradient, and was visually dominated by orange Beggiatoa. This was fringed by white Beggiatoa mat and bare, but still warm, sediment. Methane concentrations were saturating beneath the orange and white mats and at the oily site, lower beneath bare sediment, and below detection at the background site. Our initial hypotheses were that rRNA isotopic composition would be strongly influenced by methane supply, and that archaeal rRNA might be lighter than bacterial due to contributions from methanogens and anaerobic methane oxidizers. We used biotin-labeled oligonucleotides to capture Bacterial and Archaeal SSU rRNA for isotopic determination. Background-site rRNA was isotopically heaviest, and bacterial RNA from below 2 cm at the oily site was lightest, consistent with control by methane. Within the transect mat, however, the pattern was more complicated; at some sediment depths, rRNA from the mat periphery was isotopically lightest. Part of this may be due to the spatially and temporally variable paths followed by hydrothermal fluid, which can include horizontal

  2. Using natural abundance radiocarbon to trace the flux of petrocarbon to the seafloor following the Deepwater Horizon oil spill.

    PubMed

    Chanton, Jeffrey; Zhao, Tingting; Rosenheim, Brad E; Joye, Samantha; Bosman, Samantha; Brunner, Charlotte; Yeager, Kevin M; Diercks, Arne R; Hollander, David

    2015-01-20

    In 2010, the Deepwater Horizon accident released 4.6–6.0 × 10(11) grams or 4.1 to 4.6 million barrels of fossil petroleum derived carbon (petrocarbon) as oil into the Gulf of Mexico. Natural abundance radiocarbon measurements on surface sediment organic matter in a 2.4 × 10(10) m(2) deep-water region surrounding the spill site indicate the deposition of a fossil-carbon containing layer that included 1.6 to 2.6 × 10(10) grams of oil-derived carbon. This quantity represents between 0.5 to 9.1% of the released petrocarbon, with a best estimate of 3.0–4.9%. These values may be lower limit estimates of the fraction of the oil that was deposited on the seafloor because they focus on a limited mostly deep-water area of the Gulf, include a conservative estimate of thickness of the depositional layer, and use an average background or prespill radiocarbon value for sedimentary organic carbon that produces a conservative value. A similar approach using hopane tracer estimated that 4–31% of 2 million barrels of oil that stayed in the deep sea settled on the bottom. Converting that to a percentage of the total oil that entered into the environment (to which we normalized our estimate) converts this range to 1.8 to 14.4%. Although extrapolated over a larger area, our independent estimate produced similar values.

  3. Cumulative fission yields of short-lived isotopes under natural-abundance-boron-carbide-moderated neutron spectrum

    SciTech Connect

    Finn, Erin C.; Metz, Lori A.; Greenwood, Lawrence R.; Pierson, Bruce; Wittman, Richard S.; Friese, Judah I.; Kephart, Rosara F.

    2015-04-09

    The availability of gamma spectroscopy data on samples containing mixed fission products at short times after irradiation is limited. Due to this limitation, data interpretation methods for gamma spectra of mixed fission product samples, where the individual fission products have not been chemically isolated from interferences, are not well-developed. The limitation is particularly pronounced for fast pooled neutron spectra because of the lack of available fast reactors in the United States. Samples containing the actinide isotopes 233, 235, 238U, 237Np, and 239Pu individually were subjected to a 2$ pulse in the Washington State University 1 MW TRIGA reactor. To achieve a fission-energy neutron spectrum, the spectrum was tailored using a natural abundance boron carbide capsule to absorb neutrons in the thermal and epithermal region of the spectrum. Our tailored neutron spectrum is unique to the WSU reactor facility, consisting of a soft fission spectrum that contains some measurable flux in the resonance region. This results in a neutron spectrum at greater than 0.1 keV with an average energy of 70 keV, similar to fast reactor spectra and approaching that of 235U fission. Unique fission product gamma spectra were collected from 4 minutes to 1 week after fission using single-crystal high purity germanium detectors. Cumulative fission product yields measured in the current work generally agree with published fast pooled fission product yield values from ENDF/B-VII, though a bias was noted for 239Pu. The present work contributes to the compilation of energy-resolved fission product yield nuclear data for nuclear forensic purposes.

  4. Quantifying nitrogen process rates in a constructed wetland using natural abundance stable isotope signatures and stable isotope amendment experiments.

    PubMed

    Erler, Dirk V; Eyre, Bradley D

    2010-01-01

    This study describes the spatial variability in nitrogen (N) transformation within a constructed wetland (CW) treating domestic effluent. Nitrogen cycling within the CW was driven by settlement and mineralization of particulate organic nitrogen and uptake of NO3-. The concentration of NO3- was found to decrease, as the delta15N-NO3- signature increased, as water flowed through the CW, allowing denitrification rates to be estimated on the basis of the degree of fractionation of delta15N-NO3-. Estimates of denitrification hinged on the determination of a net isotope effect (eta), which was influenced byprocesses that enrich or deplete 15NO3- (e.g., nitrification), as well as the rate constants associated with the different processes involved in denitrification (i.e., diffusion and enzyme activity). The influence of nitrification on eta was quantified; however, it remained unclear how eta varied due to variability in denitrification rate constants. A series of stable isotope amendment experiments was used to further constrain the value of eta and calculate rates of denitrification, and nitrification, within the wetland. The maximum calculated rate of denitrification was 956 +/- 187 micromol N m(-2) h(-1), and the maximum rate of nitrification was 182 +/- 28.9 micromol N m(-2) h(-1). Uptake of NO3- was quantitatively more important than denitrification throughoutthe wetland. Rates of N cycling varied spatially within thewetland, with denitrification dominating in the downstream deoxygenated region of the wetland. Studies that use fractionation of N to derive rate estimates must exercise caution when interpreting the net isotope effect. We suggest a sampling procedure for future natural abundance studies that may help improve the accuracy of N cycling rate estimates.

  5. Plant and Soil Natural Abundance delta-15N: Indicators of Nitrogen Cycling in the Catskill Mountains, New York, USA

    NASA Astrophysics Data System (ADS)

    Templer, P. H.; Lovett, G. M.; Weathers, K.; Arthur, M. A.

    2002-12-01

    We examined the potential use of natural abundance 15N of plants and soils as an indicator of forest nitrogen (N) cycling rates within the Catskill Mountains, NY. These watersheds receive among the highest rates of N deposition in the northeastern United States and are beginning to show signs of N saturation. Many studies have shown a link between increased N cycling rates and 15N enrichment of soil and plant pools. Faster rates of N cycling processes, especially nitrification, lead to fractionation of 14/15N, creating N products that are relatively depleted in 15N. This can lead to enrichment of soil pools, as lighter 14N is lost from the system via leaching or denitrification. Plant N pools can become increasingly enriched as they take up 15N-enriched soil N. Despite similar amounts of N deposition across the Catskill Mountains, forests dominated by different tree species appear to vary in the amount of N retained or lost to nearby streams. To determine if plant and soil 15N could be used as indicators of N cycling rates, we collected foliage, wood, litterfall, organic and mineral soil, and fine roots from single species stands of American beech (Fagus grandifolia), eastern hemlock (Tsuga canadensis), red oak (Quercus rubra), and sugar maple (Acer saccharum). Fine roots and soil 15N were highest within sugar maple stands (p<0.05). Sugar maple soils also had the highest rates of net nitrification and N leaching. Therefore, soil 15N appears to correlate with forest N retention and loss. However, 15N enrichment was highest within foliage, litterfall and wood of beech trees (p<0.05). The decoupling between foliage 15N and N cycling, as well as between 15N of foliage and fine roots, illustrates that it may not be possible to use a single plant pool as an indicator of N cycling rates.

  6. Evaluating microbial carbon sources in Athabasca oil sands tailings ponds using natural abundance stable and radiocarbon isotopes

    NASA Astrophysics Data System (ADS)

    Ahad, J. M.; Pakdel, H.

    2013-12-01

    Natural abundance stable (δ13C) and radiocarbon (Δ14C) isotopes of phospholipid fatty acids (PLFAs) were used to evaluate the carbon sources utilized by the active microbial populations in surface sediments from Athabasca oil sands tailings ponds. The absence of algal-specific PLFAs at three of the four sites investigated, in conjunction with δ13C signatures for PLFAs that were generally within ~3‰ of that reported for oil sands bitumen (~ -30‰), indicated that the microbial communities growing on petroleum constituents were dominated by aerobic heterotrophs. The Δ14C values of PLFAs ranged from -906 to -586‰ and pointed to a significant uptake of fossil carbon (up to ~90% of microbial carbon derived from petroleum), particularly in PLFAs (e.g., cy17:0 and cy19:0) often associated with petroleum hydrocarbon degrading bacteria. The comparatively higher levels of 14C in other, less specific PLFAs (e.g., 16:0) indicated the preferential uptake of younger organic matter by the general microbial population (~50-80% of microbial carbon derived from petroleum). Since the main carbon pools in tailings sediment were essentially 'radiocarbon dead' (i.e., no detectable 14C), the principal source for this modern carbon is considered to be the Athabasca River, which provides the bulk of the water used in the bitumen extraction process. The preferential uptake of the minor amount of young and presumably more biodegradable material present in systems otherwise dominated by recalcitrant petroleum constituents has important implications for remediation strategies. On the one hand, it implies that mining-related organic contaminants could persist in the environment long after tailings pond reclamation has begun. Alternatively, it may be that the young, labile organic matter provided by the Athabasca River plays an important role in stimulating or supporting the microbial utilization of petroleum carbon in oil sands tailings ponds via co-metabolism or priming processes

  7. Chemical Modeling of Acid-Base Properties of Soluble Biopolymers Derived from Municipal Waste Treatment Materials

    PubMed Central

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Tafur Marinos, Janeth Alicia; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo

    2015-01-01

    This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials. PMID:25658795

  8. N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

    USGS Publications Warehouse

    Thorn, K.A.; Cox, L.G.

    2009-01-01

    The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS 15N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprised the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by 15N NMR. Liquid state 15N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (1H-15N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.

  9. N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

    SciTech Connect

    Thorn, Kevin A.; Cox, Larry G.

    2009-02-28

    The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS ¹⁵N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprised the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by ¹⁵N NMR. Liquid state ¹⁵N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (¹H–¹⁵N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.

  10. Mixed biopolymer systems based on starch.

    PubMed

    Abd Elgadir, M; Akanda, Md Jahurul Haque; Ferdosh, Sahena; Mehrnoush, Amid; Karim, Alias A; Noda, Takahiro; Sarker, Md Zaidul Islam

    2012-01-09

    A binary mixture of starch-starch or starch with other biopolymers such as protein and non-starch polysaccharides could provide a new approach in producing starch-based food products. In the context of food processing, a specific adjustment in the rheological properties plays an important role in regulating production processing and optimizing the applicability, stability, and sensory of the final food products. This review examines various biopolymer mixtures based on starch and the influence of their interaction on physicochemical and rheological properties of the starch-based foods. It is evident that the physicochemical and rheological characteristics of the biopolymers mixture are highly dependent on the type of starch and other biopolymers that make them up mixing ratios, mixing procedure and presence of other food ingredients in the mixture. Understanding these properties will lead to improve the formulation of starch-based foods and minimize the need to resort to chemically modified starch.

  11. Stable isotope natural abundance of nitrous oxide emitted from Antarctic tundra soils: effects of sea animal excrement depositions.

    PubMed

    Zhu, Renbin; Liu, Yashu; Li, Xianglan; Sun, Jianjun; Xu, Hua; Sun, Liguang

    2008-11-01

    Nitrous oxide (N2O), a greenhouse gas, is mainly emitted from soils during the nitrification and denitrification processes. N2O stable isotope investigations can help to characterize the N2O sources and N2O production mechanisms. N2O isotope measurements have been conducted for different types of global terrestrial ecosystems. However, no isotopic data of N2O emitted from Antarctic tundra ecosystems have been reported although the coastal ice-free tundra around Antarctic continent is the largest sea animal colony on the global scale. Here, we report for the first time stable isotope composition of N2O emitted from Antarctic sea animal colonies (including penguin, seal and skua colonies) and normal tundra soils using in situ field observations and laboratory incubations, and we have analyzed the effects of sea animal excrement depositions on stable isotope natural abundance of N2O. For all the field sites, the soil-emitted N2O was 15N- and 18O-depleted compared with N2O in local ambient air. The mean delta values of the soil-emitted N2O were delta15N = -13.5 +/- 3.2 per thousand and delta18O = 26.2 +/- 1.4 per thousand for the penguin colony, delta15N = -11.5 +/- 5.1 per thousand and delta18O = 26.4 +/- 3.5 per thousand for the skua colony and delta15N = -18.9 +/- 0.7 per thousand and delta18O = 28.8 +/- 1.3 per thousand for the seal colony. In the soil incubations, the isotopic composition of N2O was measured under N2 and under ambient air conditions. The soils incubated under the ambient air emitted very little N2O (2.93 microg N2O--N kg(-1)). Under N2 conditions, much more N2O was formed (9.74 microg N2O--N kg(-1)), and the mean delta15N and delta18O values of N2O were -19.1 +/- 8.0 per thousand and 21.3 +/- 4.3 per thousand, respectively, from penguin colony soils, and -17.0 +/- 4.2 per thousand and 20.6 +/- 3.5 per thousand, respectively, from seal colony soils. The data from in situ field observations and laboratory experiments point to denitrification as the

  12. System for measuring radioactivity of labelled biopolymers

    SciTech Connect

    Gross, V.

    1980-07-08

    A system is described for measuring radioactivity of labelled biopolymers, comprising: a set of containers adapted for receiving aqueous solutions of biological samples containing biopolymers which are subsequently precipitated in said containers on particles of diatomite in the presence of a coprecipitator, then filtered, dissolved, and mixed with a scintillator; radioactivity measuring means including a detection chamber to which is fed the mixture produced in said set of containers; an electric drive for moving said set of containers in a stepwise manner; means for proportional feeding of said coprecipitator and a suspension of diatomite in an acid solution to said containers which contain the biological sample for forming an acid precipitation of biopolymers; means for the removal of precipitated samples from said containers; precipitated biopolymer filtering means for successively filtering the precipitate, suspending the precipitate, dissolving the biopolymers mixed with said scintillator for feeding of the mixture to said detection chamber; a system of pipelines interconnecting said above-recited means; and said means for measuring radioactivity of labelled biopolymers including, a measuring cell arranged in a detection chamber and communicating with said means for filtering precipitated biopolymers through one pipeline of said system of pipelines; a program unit electrically connected to said electric drive, said means for acid precipatation of biopolymers, said means for the removal of precipitated samples from said containers, said filtering means, and said radioactivity measuring device; said program unit adapted to periodically switch on and off the above-recited means and check the sequence of the radioactivity measuring operations; and a control unit for controlling the initiation of the system and for selecting programs.

  13. Meta-analysis reveals that seed-applied neonicotinoids and pyrethroids have similar negative effects on abundance of arthropod natural enemies

    PubMed Central

    Tooker, John F.

    2016-01-01

    Background Seed-applied neonicotinoids are widely used in agriculture, yet their effects on non-target species remain incompletely understood. One important group of non-target species is arthropod natural enemies (predators and parasitoids), which contribute considerably to suppression of crop pests. We hypothesized that seed-applied neonicotinoids reduce natural-enemy abundance, but not as strongly as alternative insecticide options such as soil- and foliar-applied pyrethroids. Furthermore we hypothesized that seed-applied neonicotinoids affect natural enemies through a combination of toxin exposure and prey scarcity. Methods To test our hypotheses, we compiled datasets comprising observations from randomized field studies in North America and Europe that compared natural-enemy abundance in plots that were planted with seed-applied neonicotinoids to control plots that were either (1) managed without insecticides (20 studies, 56 site-years, 607 observations) or (2) managed with pyrethroid insecticides (eight studies, 15 site-years, 384 observations). Using the effect size Hedge’s d as the response variable, we used meta-regression to estimate the overall effect of seed-applied neonicotinoids on natural-enemy abundance and to test the influence of potential moderating factors. Results Seed-applied neonicotinoids reduced the abundance of arthropod natural enemies compared to untreated controls (d = −0.30 ± 0.10 [95% confidence interval]), and as predicted under toxin exposure this effect was stronger for insect than for non-insect taxa (QM = 8.70, df = 1, P = 0.003). Moreover, seed-applied neonicotinoids affected the abundance of arthropod natural enemies similarly to soil- or foliar-applied pyrethroids (d = 0.16 ± 0.42 or −0.02 ± 0.12; with or without one outlying study). Effect sizes were surprisingly consistent across both datasets (I2 = 2.7% for no-insecticide controls; I2 = 0% for pyrethroid controls), suggesting little moderating influence of

  14. Estimating modal abundances from the spectra of natural and laboratory pyroxene mixtures using the modified Gaussian model

    NASA Astrophysics Data System (ADS)

    Sunshine, J. M.; Pieters, C. M.

    1993-05-01

    The modified Gaussian model (MGM) is used to explore spectra of samples containing multiple pyroxene components as a function of modal abundance. The MGM allows spectra to be analyzed directly, without the use of actual or assumed end-member spectra and therefore holds great promise for remote applications. A series of mass fraction mixtures created from several different particle size fractions are analyzed with the MGM to quantify the properties of pyroxene mixtures as a function of both modal abundance and grain size. Band centers, band widths, and relative band strengths of absorptions from individual pyroxenes in mixture spectra are found to be largely independent of particle size. Spectral properties of both zoned and exsolved pyroxene components are resolved in exsolved samples using the MGM, and modal abundances are accurately estimated to within 5-10 percent without predetermined knowledge of the end-member spectra.

  15. Estimating modal abundances from the spectra of natural and laboratory pyroxene mixtures using the modified Gaussian model

    NASA Technical Reports Server (NTRS)

    Sunshine, Jessica M.; Pieters, Carle M.

    1993-01-01

    The modified Gaussian model (MGM) is used to explore spectra of samples containing multiple pyroxene components as a function of modal abundance. The MGM allows spectra to be analyzed directly, without the use of actual or assumed end-member spectra and therefore holds great promise for remote applications. A series of mass fraction mixtures created from several different particle size fractions are analyzed with the MGM to quantify the properties of pyroxene mixtures as a function of both modal abundance and grain size. Band centers, band widths, and relative band strengths of absorptions from individual pyroxenes in mixture spectra are found to be largely independent of particle size. Spectral properties of both zoned and exsolved pyroxene components are resolved in exsolved samples using the MGM, and modal abundances are accurately estimated to within 5-10 percent without predetermined knowledge of the end-member spectra.

  16. Dynamic Elasticity Model of Resilin Biopolymers

    NASA Astrophysics Data System (ADS)

    Hu, Xiao; Duki, Solomon

    2013-03-01

    Resilin proteins are `super elastic rubbers' in the flight and jumping systems of most insects, and can extend and retract millions of times. Natural resilin exhibits high resilience (> 95%) under high-frequency conditions, and could be stretched to over 300% of its original length with a low elastic modulus of 0.1-3 MPa. However, insight into the underlying molecular mechanisms responsible for resilin elasticity remains undefined. We report on the dynamic structure transitions and functions of full length resilin from fruit fly (D. melanogaster CG15920) and its different functional domains. A dynamic computational model is proposed to explain the super elasticity and energy conversion mechanisms of resilin, providing important insight into structure-function relationships for resilins, as well as other elastomeric proteins. A strong beta-turn transition was experimentally identified in the full length resilin and its non-elastic domains (Exon III). Changes in periodic long-range order were demonstrated during this transition, induced either by thermal or mechanical inputs, to confirm the universality of proposed mechanism. Further, this model offers new options for designing protein-based biopolymers with tunable material applications.

  17. Equilibrium & Nonequilibrium Fluctuation Effects in Biopolymer Networks

    NASA Astrophysics Data System (ADS)

    Kachan, Devin Michael

    Fluctuation-induced interactions are an important organizing principle in a variety of soft matter systems. In this dissertation, I explore the role of both thermal and active fluctuations within cross-linked polymer networks. The systems I study are in large part inspired by the amazing physics found within the cytoskeleton of eukaryotic cells. I first predict and verify the existence of a thermal Casimir force between cross-linkers bound to a semi-flexible polymer. The calculation is complicated by the appearance of second order derivatives in the bending Hamiltonian for such polymers, which requires a careful evaluation of the the path integral formulation of the partition function in order to arrive at the physically correct continuum limit and properly address ultraviolet divergences. I find that cross linkers interact along a filament with an attractive logarithmic potential proportional to thermal energy. The proportionality constant depends on whether and how the cross linkers constrain the relative angle between the two filaments to which they are bound. The interaction has important implications for the synthesis of biopolymer bundles within cells. I model the cross-linkers as existing in two phases: bound to the bundle and free in solution. When the cross-linkers are bound, they behave as a one-dimensional gas of particles interacting with the Casimir force, while the free phase is a simple ideal gas. Demanding equilibrium between the two phases, I find a discontinuous transition between a sparsely and a densely bound bundle. This discontinuous condensation transition induced by the long-ranged nature of the Casimir interaction allows for a similarly abrupt structural transition in semiflexible filament networks between a low cross linker density isotropic phase and a higher cross link density bundle network. This work is supported by the results of finite element Brownian dynamics simulations of semiflexible filaments and transient cross-linkers. I

  18. Impact of a nucleopolyhedrovirus bioinsecticide and selected synthetic insecticides on the abundance of insect natural enemies on maize in southern Mexico.

    PubMed

    Armenta, R; Martínez, A M; Chapman, J W; Magallanes, R; Goulson, D; Caballero, P; Cave, R D; Cisneros, J; Valle, J; Castillejos, V; Penagos, D I; García, L F; Williams, T

    2003-06-01

    The impact of commonly used organophosphate (chlorpyrifos, methamidophos), carbamate (carbaryl), and pyrethroid (cypermethrin) insecticides on insect natural enemies was compared with that of a nucleopolyhedrovirus (Baculoviridae) of Spodoptera frugiperda (J. E. Smith) (Lepidoptera Noctuidae) in maize grown in southern Mexico. Analyses of the SELECTV and Koppert Side Effects (IOBC) databases on the impact of synthetic insecticides on arthropod natural enemies were used to predict approximately 75-90% natural enemy mortality after application, whereas the bioinsecticide was predicted to have no effect. Three field trails were performed in mid- and late-whorl stage maize planted during the growing season in Chiapas State, Mexico. Synthetic insecticides were applied at product label recommended rates using a manual knapsack sprayer fitted with a cone nozzle. The biological pesticide was applied at a rate of 3 x 10(12) occlusion bodies (OBs)/ha using identical equipment. Pesticide impacts on arthropods on maize plants were quantified at intervals between 1 and 22 d postapplication. The biological insecticide based on S. frugiperda nucleopolyhedrovirus had no adverse effect on insect natural enemies or other nontarget insect populations. Applications of the carbamate, pyrethroid, and organophosphate insecticides all resulted in reduced abundance of insect natural enemies, but for a relatively short period (8-15 d). Pesticide applications made to late-whorl stage maize resulted in lesser reductions in natural enemy populations than applications made at the mid-whorl stage, probably because of a greater abundance of physical refuges and reduced spray penetration of late-whorl maize.

  19. Biophysical and biochemical characteristics of cutin, a plant barrier biopolymer.

    PubMed

    Heredia, Antonio

    2003-03-17

    Cutin is a support biopolyester involved in waterproofing the leaves and fruits of higher plants, regulating the flow of nutrients among various plant cells and organs, and minimizing the deleterious impact of pathogens. Despite the complexity and intractable nature of this biopolymer, significant progress in chemical composition, molecular architecture and, more recently, biosynthesis have been made in the past 10 years. This review is focused in the description of these advances and their physiological impacts to improve our knowledge on plant cutin, an unusual topic in most plant physiology and biochemistry books and reviews.

  20. Heteronuclear three-dimensional NMR spectroscopy. Natural abundance sup 13 C chemical shift editing of sup 1 H- sup 1 H COSY spectra

    SciTech Connect

    Fesik, S.W.; Gampe, R.T. Jr.; Zuiderweg, E.R.P. )

    1989-01-18

    It has been demonstrated that heteronuclear 3D NMR spectroscopy can be effectively applied to small molecules with {sup 13}C at natural abundance. A 78mM solution of the aminoglycoside, kanamycin A was used for this experiment. The heteronuclear 3D NMR spectroscopy is shown to be a useful method for resolving spectral overlap in all frequency domains. 10 refs., 2 figs.

  1. Cell patterning with mucin biopolymers

    PubMed Central

    Crouzier, T.; Jang, H.; Ahn, J.; Stocker, R.; Ribbeck, K.

    2014-01-01

    The precise spatial control of cell adhesion to surfaces is an endeavor that has enabled discoveries in cell biology and new possibilities in tissue engineering. The generation of cell-repellent surfaces currently requires advanced chemistry techniques and could be simplified. Here we show that mucins, glycoproteins of high structural and chemical complexity, spontaneously adsorb on hydrophobic substrates to form coatings that prevent the surface adhesion of mammalian epithelial cells, fibroblasts, and myoblasts. These mucin coatings can be patterned with micrometer precision using a microfluidic device, and are stable enough to support myoblast differentiation over seven days. Moreover, our data indicate that the cell-repellent effect is dependent on mucin-associated glycans because their removal results in a loss of effective cell-repulsion. Last, we show that a critical surface density of mucins, which is required to achieve cell-repulsion, is efficiently obtained on hydrophobic surfaces, but not on hydrophilic glass surfaces. However, this limitation can be overcome by coating glass with hydrophobic fluorosilane. We conclude that mucin biopolymers are attractive candidates to control cell adhesion on surfaces. PMID:23980712

  2. Synthetic- and bio-polymer use for runoff water quality management in irrigated agriculture.

    PubMed

    Sojka, R E; Entry, J A; Orts, W J; Morishita, D W; Ross, C W; Horne, D J

    2005-01-01

    Low concentrations of synthetic- or bio-polymers in irrigation water can nearly eliminate sediment, N, ortho- and total-P, DOM, pesticides, micro-organisms, and weed seed from runoff. These environmentally safe polymers are employed in various sensitive uses including food processing, animal feeds, and potable water purification. The most common synthetic polymer is anionic, high purity polyacrylamide (PAM), which typically provides 70-90% contaminant elimination. Excellent results are achieved adding only 10 ppm PAM to irrigation water, applying 1-2 kg ha(-1) per irrigation, costing 4 dollars - 12 dollars kg(-1). Biopolymers are less effective. Using twice or higher concentrations, existing biopolymers are approximately 60% effective as PAM, at 2-3 times the cost. A half million ha of US irrigated land use PAM for erosion control and runoff protection. The practice is spreading rapidly in the US and worldwide. Interest in development of biopolymer surrogates for PAM is high. If the supply of cheap natural gas (raw material for PAM synthesis) diminishes, industries may seek alternative polymers. Also "green" perceptions and preferences favor biopolymers for certain applications.

  3. ''Green'' Biopolymers for Improved Decontamination of Metals from Surfaces: Sorptive Characterization and Coating Properties

    SciTech Connect

    Davison, Brian H.; Kurtiz,Tanya

    1999-06-01

    The proposed research aims to develop a fundamental understanding of important biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions. Understanding how heavy metal-chelating biopolymers coat and interact with contaminated surfaces will benefit the development of novel, safe, easy-to-apply decontamination methodologies for removal of radionuclides and heavy metals. The benefits of these methodologies will include the following: (1) decreased exposure hazards for workers; (2) decreased secondary waste generation; (3) increased efficiency of decontamination; (4) positive public appeal and development of novel, nature-friendly business opportunities; and (5) lower cost of cleanup to the government. We propose to use aqueous biopolymer solutions to coat a contaminated metal surface (i.e., steel), solubilize the heavy metals (e.g., uranium) from the surface, and bind the heavy metals into the biopolymer. The biopolymer coating (containing the immobilized hazardous metal contaminants) will then be removed as a viscous film, as a dry powder, or by washing. This ''apply, wait, and remove'' procedure will reduce the amount of worker time spent in decontamination activities.

  4. ''Green'' Biopolymers for Improved Decontamination of Metals from Surfaces: Sorptive Characterization and Coating Properties

    SciTech Connect

    Davison, Brian H.; Kuritz, Tanya

    2000-06-01

    The proposed research aims to develop a fundamental understanding of important biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions. Understanding how heavy metal-chelating biopolymers coat and interact with contaminated surfaces will benefit the development of novel, safe, easy-to-apply decontamination methodologies for removal of radionuclides and heavy metals. The benefits of these methodologies will include the following: (1) decreased exposure hazards for workers; (2) decreased secondary waste generation; (3) increased efficiency of decontamination; (4) positive public appeal and development of novel, nature-friendly business opportunities; and (5) lower cost of cleanup to the government. We propose to use aqueous biopolymer solutions to coat a contaminated metal surface (i.e., steel), solubilize the heavy metals (e.g., uranium) from the surface, and bind the heavy metals into the biopolymer. The biopolymer coating (containing the immobilized hazardous metal contaminants) will then be removed as a viscous film, as a dry powder, or by washing. This ''apply, wait, and remove'' procedure will reduce the amount of worker time spent in decontamination activities.

  5. ''Green'' Biopolymers for Improved Decontamination of Metals from Surfaces: Sorptive Characterization and Coating Properties

    SciTech Connect

    Davison, Brian H.

    2002-04-30

    The proposed research aimed to develop a fundamental understanding of important biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions. Understanding how heavy metal-chelating biopolymers coat and interact with contaminated surfaces will benefit the development of novel, safe, easy-to-apply decontamination methodologies for removal of radionuclides and heavy metals. The benefits of these methodologies include the following: decreased exposure hazards for workers; decreased secondary waste generation; increased efficiency of decontamination; positive public appeal and development of novel, nature-friendly business opportunities; and lower cost of cleanup to the government. We proposed to use aqueous biopolymer solutions to coat a contaminated metal surface (i.e., steel), solubilize the heavy metals (e.g., uranium) from the surface, and bind the heavy metals into the biopolymer. The biopolymer coating (containing the immobilized hazardous metal contaminants) was to be removed as a viscous film, as a dry powder, or by washing. This ''apply, wait, and remove'' procedure will reduce the amount of worker time spent in decontamination activities.

  6. A review of experimental and modeling techniques to determine properties of biopolymer-based nanocomposites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The nonbiodegradable and nonrenewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio-nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). One of the reasons for unique properties of bio-nanocomposites is the differ...

  7. Patterns of diversity and abundance of carrion insect assemblages in the Natural Park "Hoces del Río Riaza" (central Spain).

    PubMed

    Baz, Arturo; Cifrián, Blanca; Martín-Vega, Daniel

    2014-01-01

    The patterns of diversity and abundance of the carrion insect species in the different habitats of the Natural Park "Hoces del Río Riaza" (central Spain) were studied with the use of carrion-baited traps. Representativeness of the inventories was assessed with the calculation of randomized species richness curves and nonparametric estimators. Coleoptera families, Silphidae and Dermestidae, and Diptera families, Calliphoridae and Muscidae, were dominant in every sampling habitat, but differences in the patterns of diversity and abundance were found. Lusitanian oakwood and riparian forest were the most diverse habitats with high abundance of saprophagous species, whereas more open (i.e., exposed to continuous sunlight during the day) habitats showed lower diversity values and a different species composition and distribution of species abundance, favoring thermophilous species and necrophagous species with high tolerance to different environmental conditions. Differences in the bioclimatical features of the sampled habitats are suggested to explain the composition and diversity of the carrion insect assemblages in different environments.

  8. Molecular entanglement and electrospinnability of biopolymers.

    PubMed

    Kong, Lingyan; Ziegler, Gregory R

    2014-09-03

    Electrospinning is a fascinating technique to fabricate micro- to nano-scale fibers from a wide variety of materials. For biopolymers, molecular entanglement of the constituent polymers in the spinning dope was found to be an essential prerequisite for successful electrospinning. Rheology is a powerful tool to probe the molecular conformation and interaction of biopolymers. In this report, we demonstrate the protocol for utilizing rheology to evaluate the electrospinnability of two biopolymers, starch and pullulan, from their dimethyl sulfoxide (DMSO)/water dispersions. Well-formed starch and pullulan fibers with average diameters in the submicron to micron range were obtained. Electrospinnability was evaluated by visual and microscopic observation of the fibers formed. By correlating the rheological properties of the dispersions to their electrospinnability, we demonstrate that molecular conformation, molecular entanglement, and shear viscosity all affect electrospinning. Rheology is not only useful in solvent system selection and process optimization, but also in understanding the mechanism of fiber formation on a molecular level.

  9. TOPICAL REVIEW: Biopolymer organization upon confinement

    NASA Astrophysics Data System (ADS)

    Marenduzzo, D.; Micheletti, C.; Orlandini, E.

    2010-07-01

    Biopolymers in vivo are typically subject to spatial restraints, either as a result of molecular crowding in the cellular medium or of direct spatial confinement. DNA in living organisms provides a prototypical example of a confined biopolymer. Confinement prompts a number of biophysics questions. For instance, how can the high level of packing be compatible with the necessity to access and process the genomic material? What mechanisms can be adopted in vivo to avoid the excessive geometrical and topological entanglement of dense phases of biopolymers? These and other fundamental questions have been addressed in recent years by both experimental and theoretical means. A review of the results, particularly of those obtained by numerical studies, is presented here. The review is mostly devoted to DNA packaging inside bacteriophages, which is the best studied example both experimentally and theoretically. Recent selected biophysical studies of the bacterial genome organization and of chromosome segregation in eukaryotes are also covered.

  10. Abundances of a bean bug and its natural enemy in seminatural and cultivated habitats in agricultural landscapes.

    PubMed

    Tabuchi, Ken; Taki, Hisatomo; Iwai, Hideki; Mizutani, Nobuo; Nagasaka, Koukichi; Moriya, Seiichi; Sasaki, Rikiya

    2014-04-01

    To determine differences in distribution patterns between the soybean pest Riptortus pedestris F. (Hemiptera: Alydidae) and its egg parasitoid Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) in source and cultivated habitats, we compared their abundances in soybean fields and forest edges, which were assumed to be the overwintering sites of R. pedestris. We set synthetic attractant-baited traps for both species over 2 yr in mid-August, just before R. pedestris normally colonizes soybeans. During one of the 2 yr, we also examined the rate of parasitism using an egg trap. The numbers of both R. pedestris and O. nezarae trapped at forest edges were higher than the numbers caught in soybean fields, suggesting that forest edges are important source habitats. Compared with R. pedestris, the abundance of O. nezarae in soybean fields was considerably lower than in forest edges, presumably because of differences in their dispersal abilities and their responses to landscape structure and resource distribution. Better pest control service by O. nezarae was provided at forest edges than in soybean fields. Therefore, when using pest control by O. nezarae in soybean fields, spatial arrangement and distance from the forest edge should be considered.

  11. Adsorption of biopolymers at hydrophilic cellulose-water interface.

    PubMed

    Halder, Ebrahim; Chattoraj, D K; Das, K P

    2005-04-05

    The extent of adsorption (Gamma2(1)) of bovine serum albumin (BSA), beta-lactoglobulin, lysozyme, gelatin, and DNA from aqueous solution onto the hydrophilic surface of cellulose has been measured as function of biopolymer concentration at different temperatures, pHs, and ionic strengths, and in the presence of a high concentration of inorganic salts and denaturants. In all cases, the value of Gamma2(1) increases with the increase of biopolymer concentration (X2) in bulk and it attains a maximum value at a critical mole fraction concentration X2m. The value of Gamma2m depends upon the nature of protein, temperature, pH, and ionic strength, as well as the nature of neutral salts present in excess. Gamma2m for proteins at a fixed physicochemical condition stands in the following order: Gelatin>betalactoglobulin>lysozyme>BSA. The isotherms for adsorption of DNA nucleotides on cellulose surface at pH 4.0 have been compared at different temperatures and ionic strengths, and in the presence of high concentration of inorganic salts LiCl, NaCl, KCl, and Na2SO4. Values of Gamma2m for different systems have been evaluated and critically compared. At pH 6.0 and 8.0, Gamma2(1) values of DNA nucleotides on cellulose are all negative due to the excess positive hydration of cellulose. At pH 4.0, adsorption of nucleotides of acid, alkali, and heat-denatured DNA widely differ from each other and in the presence of excess concentration of urea becomes negative. The probable mechanisms of biopolymer-cellulose adsorption in terms of polymer hydration, steric interaction, London-van der Waals, hydrophobic, and other types of interactions have been discussed qualitatively. The standard free energy change for the adsorption of protein and DNA nucleotides on the cellulose surface at the state of adsorption saturation has been calculated in kJ per kg of cellulose using an integrated form of the Gibbs adsorption equation. The relation between DeltaG degrees and maximum affinities between

  12. Constraints on abundance, composition, and nature of X-ray amorphous components of soils and rocks at Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Dehouck, Erwin; McLennan, Scott M.; Meslin, Pierre-Yves; Cousin, Agnès.

    2014-12-01

    X-ray diffraction patterns of the three samples analyzed by Curiosity's Chemistry and Mineralogy (CheMin) instrument during the first year of the Mars Science Laboratory mission—the Rocknest sand, and the John Klein and Cumberland drill fines, both extracted from the Sheepbed mudstone—show evidence for a significant amorphous component of unclear origin. We developed a mass balance calculation program that determines the range of possible chemical compositions of the crystalline and amorphous components of these samples within the uncertainties of mineral abundances derived from CheMin data. In turn, the chemistry constrains the minimum abundance of amorphous component required to have realistic compositions (all oxides ≥ 0 wt %): 21-22 wt % for Rocknest and 15-20 wt % for Cumberland, in good agreement with estimates derived from the diffraction patterns (~27 and ~31 wt %, respectively). Despite obvious differences between the Rocknest sand and the Sheepbed mudstone, the amorphous components of the two sites are chemically very similar, having comparable concentrations of SiO2, TiO2, Al2O3, Cr2O3, FeOT, CaO, Na2O, K2O, and P2O5. MgO tends to be lower in Rocknest, although it may also be comparable between the two samples depending on the exact composition of the smectite in Sheepbed. The only unambiguous difference is the SO3 content, which is always higher in Rocknest. The observed similarity suggests that the two amorphous components share a common origin or formation process. The individual phases possibly present within the amorphous components include: volcanic (or impact) glass, hisingerite (or silica + ferrihydrite), amorphous sulfates (or adsorbed SO42-), and nanophase ferric oxides.

  13. Studies on amendment of different biopolymers in sandy loam and their effect on germination, seedling growth of Gossypium herbaceum L.

    PubMed

    Patil, Satish Vitthalrao; Salunke, B K; Patil, C D; Salunkhe, R B

    2011-03-01

    Different biopolymers, agar, cellulose, alginate, psyllium gaur gum, and bacterial exopolysaccharide (EPS) powders were amended to check their efficacy in enhancing maximum water holding capacity (MWHC), permanent wilting point (PWP), and germination and seedling growth of the Gossypium herbaceum in a laboratory scale. The efficacy of all biopolymers for enhancement of MWHC, PWP, and growth was also analyzed by measuring organic carbon, organic matter, total nitrogen, respiration rate, and microflora in amended and control sandy loams. The range of concentrations (0.2-2%) of all biopolymers was incorporated in sandy loam containing pots. The soil without polymer was considered as control. The psyllium (0.6%) and bacterial EPS (1%) amended soil has 242 and 233% increase in MWHC and thus delaying in the permanent wilting point by 108 and 84 h at 37 °C, respectively, as compared to control. All biopolymers found to increase more or less MWHC, organic matter, total nitrogen, microflora, and PWP as compared to control. The psyllium and bacterial EPS show the highest increase organic matter, biomass, and microflora. The highest reduction in MWHC after 12 weeks were observed in cellulose, gaur gum, and alginate; besides, psyllium, bacterial EPS, and agar showed comparatively less reduction MWHC, i.e., 24% and 14.5%, respectively. The toxicity studies of biopolymer were carried out on earthworm (Eisenia foetida). It revealed their nontoxic nature. The biopolymer amendment in sandy loam can be an effective strategy to improved soil texture, fertility, and thereby crop yield.

  14. Exploring Modifications of Cotton with Biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biopolymers including starch, alginate, and chitosan were grafted on to both nonwoven and woven cotton fabrics to examine their hemostatic and antimcrobial properties. The development of cotton-based health care fabrics that promote blood clotting and prevent microbial growth have wide applicability...

  15. Production of biopolymer composites by particle bonding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report describes a new technology to produce biopolymer composites at room temperature. During the process, micrometer-scale raw material is coated with zein that has strong adhesive property, which is then compressed to form a rigid material. Since this technology does not require purificati...

  16. Production of biopolymer composites by particle bonding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article describes a new process, particle-bonding technology, to produce biopolymer composites from agricultural commodities. In this technology, matrix-protein complexes are formed by the interaction of micrometer-scale matrix material with an adhesive protein, zein. This spontaneous process m...

  17. Seasonal variation in species composition and abundance of demersal fish and invertebrates in a Seagrass Natural Reserve on the eastern coast of the Shandong Peninsula, China

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Guo, Dong; Zhang, Peidong; Zhang, Xiumei; Li, Wentao; Wu, Zhongxin

    2016-03-01

    Seagrass habitats are structurally complex ecosystems, which support high productivity and biodiversity. In temperate systems the density of seagrass may change seasonally, and this may influence the associated fish and invertebrate community. Little is known about the role of seagrass beds as possible nursery areas for fish and invertebrates in China. To study the functioning of a seagrass habitat in northern China, demersal fish and invertebrates were collected monthly using traps, from February 2009 to January 2010. The density, leaf length and biomass of the dominant seagrass Zostera marina and water temperature were also measured. The study was conducted in a Seagrass Natural Reserve (SNR) on the eastern coast of the Shandong Peninsula, China. A total of 22 fish species and five invertebrate species were recorded over the year. The dominant fish species were Synechogobius ommaturus, Sebastes schlegelii, Pholis fangi, Pagrus major and Hexagrammos otakii and these species accounted for 87% of the total number of fish. The dominant invertebrate species were Charybdis japonica and Octopus variabilis and these accounted for 98% of the total abundance of invertebrates. There was high temporal variation in species composition and abundance. The peak number of fish species occurred in August-October 2009, while the number of individual fish and biomass was highest during November 2009. Invertebrate numbers and biomass was highest in March, April, July and September 2009. Temporal changes in species abundance of fishes and invertebrates corresponded with changes in the shoot density and leaf length of the seagrass, Zostera marina.

  18. Something borrowed, something blue: The nature of blue metal-poor stars inferred from their colours and chemical abundances

    NASA Astrophysics Data System (ADS)

    Hansen, C. J.; Jofré, P.; Koch, A.; McWilliam, A.; Sneden, C. S.

    2017-01-01

    Blue metal-poor (BMP) stars are main sequence stars that appear bluer and more luminous than normal turnoff stars. They were originally singled out by using B-V and U-B colour cuts.Early studies found that a larger fraction of field BMP stars were binaries compared to normal halo stars. Thus, BMP stars are ideal field blue straggler candidates for investigating internal stellar evolution processes and binary interaction. In particular, the presence or depletion in lithium in their spectra is a powerful indicator of their origin. They are either old, halo blue stragglers experiencing internal mixing processes or mass transfer (Li-depletion), or intermediate-age, single stars of possibly extragalactic origin (2.2 dex halo plateau Li). However, we note that internal mixing processes can lead to an increased level of Li. Hence, this study combines photometry and spectroscopy to unveil the origin of various BMP stars. We first show how to separate binaries from young blue stars using photometry, metallicity and lithium. Using a sample of 80 BMP stars (T > 6300 K), we find that 97% of the BMP binaries have V-Ks0 < 1.08 ± 0.03, while BMP stars that are not binaries lie above this cut in two thirds of the cases. This cut can help classify stars that lack radial velocities from follow-up observations. We then trace the origin of two BMP stars from the photometric sample by conducting a full chemical analysis using new high-resolution and high signal-to-noise spectra. Based on their radial velocities, Li, α and s- and r-process abundances we show that BPS CS22874-042 is a single star (A(Li) = 2.38 ± 0.10 dex) while with A(Li)= 2.23 ± 0.07 dex CD-48 2445 is a binary, contrary to earlier findings. Our analysis emphasises that field blue stragglers can be segregated from single metal-poor stars, using (V-Ks) colours with a fraction of single stars polluting the binary sample, but not vice versa. These two groups can only be properly separated by using information from

  19. Plant diversity moderates drought stress in grasslands: Implications from a large real-world study on (13)C natural abundances.

    PubMed

    Klaus, Valentin H; Hölzel, Norbert; Prati, Daniel; Schmitt, Barbara; Schöning, Ingo; Schrumpf, Marion; Solly, Emily F; Hänsel, Falk; Fischer, Markus; Kleinebecker, Till

    2016-10-01

    Land-use change and intensification play a key role in the current biodiversity crisis. The resulting species loss can have severe effects on ecosystem functions and services, thereby increasing ecosystem vulnerability to climate change. We explored whether land-use intensification (i.e. fertilization intensity), plant diversity and other potentially confounding environmental factors may be significantly related to water use (i.e. drought stress) of grassland plants. Drought stress was assessed using δ(13)C abundances in aboveground plant biomass of 150 grassland plots across a gradient of land-use intensity. Under water shortage, plants are forced to increasingly take up the heavier (13)C due to closing stomata leading to an enrichment of (13)C in biomass. Plants were sampled at the community level and for single species, which belong to three different functional groups (one grass, one herb, two legumes). Results show that plant diversity was significantly related to the δ(13)C signal in community, grass and legume biomass indicating that drought stress was lower under higher diversity, although this relation was not significant for the herb species under study. Fertilization, in turn, mostly increased drought stress as indicated by more positive δ(13)C values. This effect was mostly indirect by decreasing plant diversity. In line with these results, we found similar patterns in the δ(13)C signal of the organic matter in the topsoil, indicating a long history of these processes. Our study provided strong indication for a positive biodiversity-ecosystem functioning relationship with reduced drought stress at higher plant diversity. However, it also underlined a negative reinforcing situation: as land-use intensification decreases plant diversity in grasslands, this might subsequently increases drought sensitivity. Vice-versa, enhancing plant diversity in species-poor agricultural grasslands may moderate negative effects of future climate change.

  20. Supportive breeding boosts natural population abundance with minimal negative impacts on fitness of a wild population of Chinook salmon

    PubMed Central

    Hess, Maureen A; Rabe, Craig D; Vogel, Jason L; Stephenson, Jeff J; Nelson, Doug D; Narum, Shawn R

    2012-01-01

    While supportive breeding programmes strive to minimize negative genetic impacts to populations, case studies have found evidence for reduced fitness of artificially produced individuals when they reproduce in the wild. Pedigrees of two complete generations were tracked with molecular markers to investigate differences in reproductive success (RS) of wild and hatchery-reared Chinook salmon spawning in the natural environment to address questions regarding the demographic and genetic impacts of supplementation to a natural population. Results show a demographic boost to the population from supplementation. On average, fish taken into the hatchery produced 4.7 times more adult offspring, and 1.3 times more adult grand-offspring than naturally reproducing fish. Of the wild and hatchery fish that successfully reproduced, we found no significant differences in RS between any comparisons, but hatchery-reared males typically had lower RS values than wild males. Mean relative reproductive success (RRS) for hatchery F1 females and males was 1.11 (P = 0.84) and 0.89 (P = 0.56), respectively. RRS of hatchery-reared fish (H) that mated in the wild with either hatchery or wild-origin (W) fish was generally equivalent to W × W matings. Mean RRS of H × W and H × H matings was 1.07 (P = 0.92) and 0.94 (P = 0.95), respectively. We conclude that fish chosen for hatchery rearing did not have a detectable negative impact on the fitness of wild fish by mating with them for a single generation. Results suggest that supplementation following similar management practices (e.g. 100% local, wild-origin brood stock) can successfully boost population size with minimal impacts on the fitness of salmon in the wild. PMID:23025818

  1. Seasonal Abundance and Natural Inoculativity of Insect Vectors of Xylella fastidiosa in Oklahoma Tree Nurseries and Vineyards.

    PubMed

    Overall, Lisa M; Rebek, Eric J

    2015-12-01

    Xylella fastidiosa is the causative agent of diseases of perennial plants including peach, plum, elm, oak, pecan, and grape. This bacterial pathogen is transmitted by xylem-feeding insects. In recent years, Pierce's disease of grape has been detected in 10 counties in central and northeastern Oklahoma, prompting further investigation of the disease epidemiology in this state. We surveyed vineyards and tree nurseries in Oklahoma for potential insect vectors to determine species composition, infectivity, and natural inoculativity of commonly captured insect vectors. Yellow sticky cards were used to sample insect fauna at each location. Insects were removed from sticky cards and screened for X. fastidiosa using immunocapture-PCR to determine their infectivity. A second objective was to test the natural inoculativity of insect vectors that are found in vineyards. Graphocephala versuta (Say), Graphocephala coccinea (Forster), Paraulacizes irrorata (F.), Oncometopia orbona (F.), Cuerna costalis (F.), and Entylia carinata Germar were collected from vineyards and taken back to the lab to determine their natural inoculativity. Immunocapture-PCR was used to test plant and insect samples for presence of X. fastidiosa. The three most frequently captured species from vineyards and tree nurseries were G. versuta, Clastoptera xanthocephala Germar, and O. orbona. Of those insects screened for X. fastidiosa, 2.4% tested positive for the bacterium. Field-collected G. versuta were inoculative to both ragweed and alfalfa. Following a 7-d inoculation access period, a higher percentage of alfalfa became infected than ragweed. Results from this study provide insight into the epidemiology of X. fastidiosa in Oklahoma.

  2. What's on the menu? Assessing microbial carbon sources and cycling in soils using natural abundance radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    Mahmoudi, N.; Burns, L.; Mancini, S.; Fulthorpe, R.; Slater, G. F.

    2011-12-01

    Organic matter in soils is composed of diverse materials in various stages of decomposition. Soil organic matter is not in a single pool but rather in multiple carbon pools with different intrinsic turnover times that can be on annual to decadal and even millennial timescales. Microorganisms can influence the total amount of carbon stored in soils and the turnover rates of these different pools. However, the links between microbes and their ability to utilize these various carbon pools are not well understood. Moreover, microbes have been shown to co-utilize a number of available carbon sources rather than a single carbon source under soil conditions which creates difficulties in identifying microbial carbon sources in the natural environment. Compound-specific radiocarbon analysis of microbial phospholipid fatty acids (PLFA) has become a useful tool in elucidating microbial carbon sources in complex environments with multiple carbon sources. We investigated microbial carbon cycling at an industrial site in Ontario which included a variety of carbon sources including vegetation, PAHs and natural organic matter (NOM). Using this approach, the 14C content of microbial membrane lipids (which reflects their carbon source) can be compared to surrounding carbon sources in order to assess which carbon source they are metabolizing and incorporating into their lipids. In addition, we assessed microbial community structure and diversity by analyzing amplified bacterial, eukaryotic and archaeal rDNA fragments with denaturing gel gradient electrophoresis (DGGE). The Δ14C value for PLFAs ranged from +54 to -697% which indicates that microbial carbon sources across soils differ. The Δ14CPLFA for some soils is consistent with modern carbon sources while Δ14CPLFA for other soils is consistent with natural organic matter including older pools of carbon. The microbial communities at this site are not metabolizing PAHs but rather they are utilizing various pools of natural organic

  3. Understanding anisotropy and architecture in ice-templated biopolymer scaffolds.

    PubMed

    Pawelec, K M; Husmann, A; Best, S M; Cameron, R E

    2014-04-01

    Biopolymer scaffolds have great therapeutic potential within tissue engineering due to their large interconnected porosity and biocompatibility. Using an ice-templated technique, where collagen is concentrated into a porous network by ice nucleation and growth, scaffolds with anisotropic pore architecture can be created, mimicking natural tissues like cardiac muscle and bone. This paper describes a systematic set of experiments undertaken to understand the effect of local temperatures on architecture in ice-templated biopolymer scaffolds. The scaffolds within this study were at least 10mm in all dimensions, making them applicable to critical sized defects for biomedical applications. It was found that monitoring the local freezing behavior within the slurry was critical to predicting scaffold structure. Aligned porosity was produced only in parts of the slurry volume which were above the equilibrium freezing temperature (0°C) at the time when nucleation first occurs in the sample as a whole. Thus, to create anisotropic scaffolds, local slurry cooling rates must be sufficiently different to ensure that the equilibrium freezing temperature is not reached throughout the slurry at nucleation. This principal was valid over a range of collagen slurries, demonstrating that by monitoring the temperature within slurry during freezing, scaffold anisotropy with ice-templated scaffolds can be predicted.

  4. Synthesis of 9-oxononanoic acid, a precursor for biopolymers.

    PubMed

    Otte, Konrad B; Kirtz, Marko; Nestl, Bettina M; Hauer, Bernhard

    2013-11-01

    Polymers based on renewable resources have become increasingly important. The natural functionalization of fats and oils enables an easy access to interesting monomeric building blocks, which in turn transform the derivative biopolymers into high-performance materials. Unfortunately, interesting building blocks of medium-chain length are difficult to obtain by traditional chemical means. Herein, a biotechnological pathway is established that could provide an environmentally suitable and sustainable alternative. A multiple enzyme two-step one-pot process efficiently catalyzed by a coupled 9S-lipoxygenase (St-LOX1, Solanum tuberosum) and 9/13-hydroperoxide lyase (Cm-9/13HPL, Cucumis melo) cascade reaction is proposed as a potential route for the conversion of linoleic acid into 9-oxononanoic acid, which is a precursor for biopolymers. Lipoxygenase catalyzes the insertion of oxygen into linoleic acid through a radical mechanism to give 9S-hydroperoxy-octadecadienoic acid (9S-HPODE) as a cascade intermediate, which is subsequently cleaved by the action of Cm-9/13HPL. This one-pot process afforded a yield of 73 % combined with high selectivity. The best reaction performance was achieved when lipoxygenase and hydroperoxide lyase were applied in a successive rather than a simultaneous manner. Green leaf volatiles, which are desired flavor and fragrance products, are formed as by-products in this reaction cascade. Furthermore, we have investigated the enantioselectivity of 9/13-HPLs, which exhibited a strong preference for 9S-HPODE over 9R-HPODE.

  5. Dynamic nuclear polarization NMR enables the analysis of Sn-Beta zeolite prepared with natural abundance ¹¹⁹Sn precursors.

    PubMed

    Gunther, William R; Michaelis, Vladimir K; Caporini, Marc A; Griffin, Robert G; Román-Leshkov, Yuriy

    2014-04-30

    The catalytic activity of tin-containing zeolites, such as Sn-Beta, is critically dependent on the successful incorporation of the tin metal center into the zeolite framework. However, synchrotron-based techniques or solid-state nuclear magnetic resonance (ssNMR) of samples enriched with (119)Sn isotopes are the only reliable methods to verify framework incorporation. This work demonstrates, for the first time, the use of dynamic nuclear polarization (DNP) NMR for characterizing zeolites containing ~2 wt % of natural abundance Sn without the need for (119)Sn isotopic enrichment. The biradicals TOTAPOL, bTbK, bCTbK, and SPIROPOL functioned effectively as polarizing sources, and the solvent enabled proper transfer of spin polarization from the radical's unpaired electrons to the target nuclei. Using bCTbK led to an enhancement (ε) of 75, allowing the characterization of natural-abundance (119)Sn-Beta with excellent signal-to-noise ratios in <24 h. Without DNP, no (119)Sn resonances were detected after 10 days of continuous analysis.

  6. Variation in the natural abundance of (15)N in the halophyte, Salicornia virginica, associated with groundwater subsidies of nitrogen in a southern California salt-marsh.

    PubMed

    Page, Henry M

    1995-10-01

    To provide insight into the importance of the salt-marsh ecotone as a sink for inorganic nitrogen in perched groundwater, measurements were made of the natural abundance of (15)N in dissolved NO3-N and NH4-N and in the salt-marsh halophyte, Salicornia virginica, along an environmental gradient from agricultural land into a salt-marsh. The increase in the natural abundance of (15)N (expressed by convention as δ(15)N) of NO3-N, accompanied by the decrease in NO3-N (and total dissolved inorganic N, DIN) concentration along the gradient, suggested that the salt-marsh ecotone is a site of transformation, most likely through denitrification, of inorganic nitrogen in groundwater. (15)N enrichment in S. virginica (and the parasitic herb, Cuscuta salina), along the tidal marsh boundary, relative to high and middle marsh locations, indicated the retention of groundwater nitrogen as vegetative biomass. The correlation between δ(15)N Salicornia and δ(15)NNH4 suggested a preference for NH4-N over NO3-N during uptake by this plant. Groundwater inputs enhanced the standing crop, above-ground productivity, and nitrogen content of S. virginica but the ralative effects of pore water salinity and DIN concentration on these parameters were not determined. (15)N enrichment of marsh plants by groundwater DIN inputs could prove useful in tracing the fate of these inputs in the marsh food web.

  7. In Situ Natural Abundance (17)O and (25)Mg NMR Investigation of Aqueous Mg(OH)2 Dissolution in the Presence of Supercritical CO2.

    PubMed

    Hu, Mary Y; Deng, Xuchu; Thanthiriwatte, K Sahan; Jackson, Virgil E; Wan, Chuan; Qafoku, Odeta; Dixon, David A; Felmy, Andrew R; Rosso, Kevin M; Hu, Jian Zhi

    2016-11-15

    We report an in situ high-pressure NMR capability that permits natural abundance (17)O and (25)Mg NMR characterization of dissolved species in aqueous solution and in the presence of supercritical CO2 fluid (scCO2). The dissolution of Mg(OH)2 (brucite) in a multiphase water/scCO2 fluid at 90 atm pressure and 50 °C was studied in situ, with relevance to geological carbon sequestration. (17)O NMR spectra allowed identification and distinction of various fluid species including dissolved CO2 in the H2O-rich phase, scCO2, aqueous H2O, and HCO3(-). The widely separated spectral peaks for various species can all be observed both dynamically and quantitatively at concentrations as low as 20 mM. Measurement of the concentrations of these individual species also allows an in situ estimate of the hydrogen ion concentration, or pCH(+) values, of the reacting solutions. The concentration of Mg(2+) can be observed by natural abundance (25)Mg NMR at a concentration as low as 10 mM. Quantum chemistry calculations of the NMR chemical shifts on cluster models aided in the interpretation of the experimental results. Evidence for the formation of polymeric Mg(2+) clusters at high concentrations in the H2O-rich phase, a possible critical step needed for magnesium carbonate formation, was found.

  8. Structure and Properties of Polysaccharide Based BioPolymer Gels

    NASA Astrophysics Data System (ADS)

    Prud'Homme, Robert K.

    2000-03-01

    Nature uses the pyranose ring as the basic building unit for a wideclass of biopolymers. Because of their biological origin these biopolymers naturally find application as food additives, rheology modifiers. These polymers range from being rigid skeletal material, such as cellulose that resist dissolution in water, to water soluble polymers, such as guar or carrageenan. The flexibility of the basic pyranose ring structure to provide materials with such a wide range of properties comes from the specific interactions that can be engineered by nature into the structure. We will present several examples of specific interactions for these systems: hydrogen bonding, hydrophobic interactions, and specific ion interactions. The relationship between molecular interations and rheology will be emphasized. Hydrogen bonding mediated by steric interference is used to control of solubility of starch and the rheology of guar gels. A more interesting example is the hydrogen bonding induced by chemical modification in konjac glucomannan that results in a gel that melts upon cooling. Hydrogen bonding interactions in xanthan lead to gel formation at very low polymer concentrations which is a result of the fine tuning of the polymer persistence length and total contour length. Given the function of xanthan in nature its molecular architecture has been optimized. Hydrophobic interactions in methylcellulose show a reverse temperature dependence arising from solution entropy. Carrageenan gelation upon the addition of specific cations will be addressed to show the interplay of polymer secondary structure on chemical reactivity. And finally the cis-hydroxyls on galactomannans permit crosslinking by a variety of metal ions some of which lead to "living gels" and some of which lead to permanently crosslinked networks.

  9. Simultaneous preparation of naturally abundant and rare catechins by tannase-mediated biotransformation combining high speed counter current chromatography.

    PubMed

    Xia, Guobin; Hong, Shan; Liu, Songbai

    2014-05-15

    Simultaneous preparation of naturally rare catechins, EGC and EC, has been realized by tannase-mediated biotransformation combining high speed counter current chromatography. In addition, simultaneous preparation of the four catechins, EGCG, ECG, EGC, and EC in green tea extract has also been achieved by HSCCC under the normal phase and the reversed phase modes. The identity of the catechins was determined by HPLC-DAD-ESI-MS and quantification of the catechins was performed by HPLC-DAD. In a typical HSCCC separation, 27.2 mg 98.8% EGCG, 14.1 mg 94.7% EGC, and 9.3 mg 97.5% EC were obtained. This new method is efficient, time-saving and valuable for biological studies.

  10. Natural hybrids in Atlantic eels (Anguilla anguilla, A. rostrata): evidence for successful reproduction and fluctuating abundance in space and time.

    PubMed

    Albert, Vicky; Jónsson, Bjarni; Bernatchez, Louis

    2006-06-01

    The outcome of natural hybridization is highly variable and depends on the nonexclusive effects of both pre- and post-mating reproductive barriers. The objective of this study was to address three specific questions regarding the dynamics of hybridization between the American and European eels (Anguilla rostrata and Anguilla anguilla). Using 373 AFLP loci, 1127 eels were genotyped, representing different life stages from both continents, as well as multiple Icelandic locations. We first evaluated the extent of hybridization and tested for the occurrence of hybrids beyond the first generation. Second, we tested whether hybrids were randomly distributed across continents and among Icelandic sampling sites. Third, we tested for a difference in the proportion of hybrids between glass eel and yellow eel stages in Iceland. Our results provided evidence for (i) an overall hybrid proportion of 15.5% in Iceland, with values ranging from 6.7% to 100% depending on life stages and locations; (ii) the existence of hybrids beyond the first generation; (iii) a nonrandom geographic distribution of hybrids in the North Atlantic; and (iv) a higher proportion of first and later generation hybrids in yellow eels compared to glass eels, as well as a significant latitudinal gradient in the proportion of hybrids in Icelandic freshwater. We propose that the combined effect of both differential survival of hybrids and variation in hybridization rate through time best explain these patterns. We discuss the possibility that climate change, which is impacting many environmental features in the North Atlantic, may have a determinant effect on the outcome of natural hybridization in Atlantic eels.

  11. Determination of Natural 14C Abundances in Dissolved Organic Carbon in Organic-Rich Marine Sediment Porewaters by Thermal Sulfate Reduction

    NASA Astrophysics Data System (ADS)

    Johnson, L.; Komada, T.

    2010-12-01

    The abundances of natural 14C in dissolved organic carbon (DOC) in the marine environment hold clues regarding the processes that influence the biogeochemical cycling of this large carbon reservoir. At present, UV irradiation is the widely accepted method for oxidizing seawater DOC for determination of their 14C abundances. This technique yields precise and accurate values with low blanks, but it requires a dedicated vacuum line, and hence can be difficult to implement. As an alternative technique that can be conducted on a standard preparatory vacuum line, we modified and tested a thermal sulfate reduction method that was previously developed to determine δ13C values of marine DOC (Fry B. et al., 1996. Analysis of marine DOC using a dry combustion method. Mar. Chem., 54: 191-201.) to determine the 14C abundances of DOC in marine sediment porewaters. In this method, the sample is dried in a 100 ml round-bottom Pyrex flask in the presence of excess oxidant (K2SO4) and acid (H3PO4), and combusted at 550 deg.C. The combustion products are cryogenically processed to collect and quantify CO2 using standard procedures. Materials we have oxidized to date range from 6-24 ml in volume, and 95-1500 μgC in size. The oxidation efficiency of this method was tested by processing known amounts of reagent-grade dextrose and sucrose (as examples of labile organic matter), tannic acid and humic acid (as examples of complex natural organic matter), and porewater DOC extracted from organic-rich nearshore sediments. The carbon yields for all of these materials averaged 99±4% (n=18). The 14C abundances of standard materials IAEA C-6 and IAEA C-5 processed by this method using >1mgC aliquots were within error of certified values. The size and the isotopic value of the blank were determined by a standard dilution technique using IAEA C-6 and IAEA C-5 that ranged in size from 150 to 1500 μgC (n=4 and 2, respectively). This yielded a blank size of 6.7±0.7 μgC, and a blank isotopic

  12. Cadmium burden of men and women who report regular consumption of confectionery sunflower kernels containing a natural abundance of cadmium.

    PubMed Central

    Reeves, P G; Vanderpool, R A

    1997-01-01

    Because of inherent genetic and physiological characteristics, the natural concentration of cadmium in the kernels of sunflowers grown in uncontaminated soils of the northern Great Plains region of the United States is higher than in most other grains. We tested the hypothesis that a habitual consumption of sunflower kernels will increase the body burden and health effects of cadmium in humans. Sixty-six men and women who reported consuming various amounts of sunflower kernels were recruited and divided by sex and kernel consumption: those who consumed less than or equal to 1 ounce(oz)/week and those who consumed more than 1 oz/week. Cadmium intake was assessed by calculation from 7-day food diaries, cadmium burden by whole blood cadmium, red blood cell (RBC) cadmium and urine cadmium concentrations, and health effects by urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) activity and beta2-microglobulin (beta2MG). The results showed that high intakes of sunflower kernels (>1 oz/day) significantly increased the intake of cadmium (p<0.004). However, the amount of cadmium in whole blood or RBCs was not affected by cadmium intake. Urinary excretion of cadmium also was not affected by cadmium intake. Urine NAG activity and the amount of urinary beta2MG were significantly elevated in the urine of high sunflower kernel consumers when the values were expressed on a urine volume basis (p<0.03), but not when expressed on a creatinine basis (p>0.05). Because normal ranges for the excretion of these protein markers have not been established, it was not possible to determine if these elevated values were meaningful. However, given the knowledge that habitual consumption of sunflower kernels with natural cadmium concentrations higher than most other food products will increase the average intake of dietary cadmium, the potential exists for an increased body burden of cadmium. Controlled feeding studies in humans should be pursued in order to determine if the body burden

  13. Natural abundance of Sb and Sc in pristine groundwaters, Springwater Township, Ontario, Canada, and implications for tracing contamination from landfill leachates.

    PubMed

    Shotyk, William; Krachler, Michael; Chen, Bin; Zheng, James

    2005-12-01

    Using ICP-SMS and the clean lab methods and procedures developed for determining trace element concentrations in polar snow and ice, a lower limit of detection (LOD) of 30 pg l(-1) for Sb and 5 pg l(-1) for Sc was achieved, allowing the natural abundances of Sb and Sc to be measured in pristine groundwaters. Water samples were collected from natural flows and wells between Elmvale and Wyevale in Springwater Township, Ontario, Canada. The water in this region is derived from chemical reactions between meteoric fluids and the Quaternary sediments which cover the bedrock (dolomitic limestone) to depths of more than 100 m. The chemical composition of these waters (pH 8) is primarily a reflection of reactions between the percolating fluids with calcite and dolomite. The maximum concentration of Sb was 5.0 ng l(-1), and the average of all samples collected was 2.2 +/- 1.2 ng l(-1) (n = 34). The average concentration of Sc was 8.6 +/- 4.7 ng l(-1) (n = 28). The paucity of published Sb concentration data available for comparison is probably because most of the analytical methods commonly used to date, including GFAAS, HG-AAS, HG-AFS, INAA, and ICP-QMS, have lower limits of detection which are inadequate for reliably determining the natural abundance of Sb in many uncontaminated groundwaters. Also, the measurement of extremely low concentrations of Sb requires extra care to avoid possible contamination. Given the extensive use of Sb in plastics, we show that some of the containers used to collect and store samples, and for handling and preparing samples for chemical analyses, may be important sources of contamination in the laboratory. The Sb and Sc concentrations reported here should serve as reference values for this region, against which contamination by various human impacts in future could be compared.

  14. Effect of petroleum products on the decomposition of soil organic matter as assessed by 13C natural abundance

    NASA Astrophysics Data System (ADS)

    Stelmach, Wioleta; Szarlip, Paweł; Trembaczowski, Andrzej; Bieganowski, Andrzej

    2016-04-01

    Petroleum products are common contaminants in soils due to human activities. They are toxic for microorganisms and threat their functions, including decomposition of soil organic matter (SOM). The direct estimation of altered SOM decomposition - based on the CO2 emission - is impossible after oil contamination, because oil decomposition also contributes to the CO2 release. We used the natural differences in the isotopic signature (δ13C) of SOM and of oil products to partition the total CO2 for both sources and to analyze the suppression of SOM decomposition. The dynamics of 13C fractionation during the mineralization of gasoline and diesel was measured during 42 days. The 13C fractionation varied between -8.8‰ and +3.6‰ within the first 10 days, and stabilized thereafter at about -5.3‰ for gasoline and +3.2‰ for diesel. These 13C fractionations and δ13C values of CO2 emitted from the soil were used for correct partitioning of the total CO2. Contamination with gasoline reduced the CO2 efflux from SOM decomposition by a factor of 25 (from 151 to 6 mg C-CO2 kg-1 soil during 42 days). The negative effect of diesel was much lower: the CO2 efflux from SOM was decreased by less than a factor of 2. The strong effect of gasoline versus diesel reflects the lower absorption of gasoline to mineral particles and the development of a thin film on water surfaces, leading to toxicity for microorganisms. We conclude that the small differences of 13C of SOM and of organic pollutants can be used to partition CO2 fluxes and analyze pollutant effects on SOM decomposition.

  15. Chemical modification of cellulosic biopolymer and its use in removal of heavy metal ions from wastewater.

    PubMed

    Singha, A S; Guleria, Ashish

    2014-06-01

    Use of biological macromolecules for wastewater remediation process has become the topic of intense research mostly driven by growing concerns about the depletion of petroleum oil reserves and environmental problems. So in view of technological significance of cellulosic biopolymers in various fields, the present study is an attempt to synthesize cellulosic biopolymers based graft copolymers using free radical polymerization. The resulting cellulosic polymers were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric (TGA) analysis. Furthermore, modified cellulosic biopolymer was used in removal of Cu(2+), Zn(2+), Cd(2+) and Pb(2+) toxic metal ions from wastewater. The effects of pH, contact time, temperature and metal ions concentration were studied in batch mode experiments. Langmuir and Dubinin-Radushkevich (D-R) models were used to show the adsorption isotherm. The maximum monolayer capacity qm calculated using Langmuir isotherm for Cu(2+), Zn(2+), Cd(2+), Pb(2+) metal ions were 1.209, 0.9623, 1.2609 and 1.295mmol/g, respectively. The thermodynamic parameters ΔH° and ΔG° values for metal ions adsorption on modified cellulosic biopolymer showed that adsorption process was spontaneous as well as exothermic in nature.

  16. Biopolymer-Based Nanoparticles for Drug/Gene Delivery and Tissue Engineering

    PubMed Central

    Nitta, Sachiko Kaihara; Numata, Keiji

    2013-01-01

    There has been a great interest in application of nanoparticles as biomaterials for delivery of therapeutic molecules such as drugs and genes, and for tissue engineering. In particular, biopolymers are suitable materials as nanoparticles for clinical application due to their versatile traits, including biocompatibility, biodegradability and low immunogenicity. Biopolymers are polymers that are produced from living organisms, which are classified in three groups: polysaccharides, proteins and nucleic acids. It is important to control particle size, charge, morphology of surface and release rate of loaded molecules to use biopolymer-based nanoparticles as drug/gene delivery carriers. To obtain a nano-carrier for therapeutic purposes, a variety of materials and preparation process has been attempted. This review focuses on fabrication of biocompatible nanoparticles consisting of biopolymers such as protein (silk, collagen, gelatin, β-casein, zein and albumin), protein-mimicked polypeptides and polysaccharides (chitosan, alginate, pullulan, starch and heparin). The effects of the nature of the materials and the fabrication process on the characteristics of the nanoparticles are described. In addition, their application as delivery carriers of therapeutic drugs and genes and biomaterials for tissue engineering are also reviewed. PMID:23344060

  17. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities

    PubMed Central

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C. B.; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications. PMID:27304672

  18. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities.

    PubMed

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C B; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications.

  19. 13C Natural Abundance in Serum Retinol Acts as a Biomarker for Increases in Dietary Provitamin A

    PubMed Central

    Howe, Julie A; Valentine, Ashley R; Hull, Angela K; Tanumihardjo, Sherry A

    2009-01-01

    The natural isotopic composition of 13C and 12C in tissues is largely determined by the diet. Sources of provitamin A carotenoids (e.g., vegetables) typically have a lower 13C to 12C ratio (13C:12C) than preformed vitamin A sources (i.e., dairy and meat) from corn-fed animals, which are prevalent in the US. The 13C:12C of serum retinol (13C:12C-retinol) was evaluated as a biomarker for vegetable intake in a 3-mo dietary intervention designed to promote weight-loss by increased vegetable consumption or reduced calorie and fat intake. Subjects were 21–50 y of age with a BMI between 30–40 kg/m2 and were enrolled from one geographic area in the US. The high vegetable group (n = 20) was encouraged to increase daily vegetable and fruit consumption to 0.95 liter vegetables and 0.24–0.35 liter fruits. The caloric reduction group (n = 17) was encouraged to lower caloric intake by 500 kcal and consume ≤25% kcal from fat daily. Provided meals supplied 75–100% vegetable and fruit goals and 50–67% kcal and fat g per day. Carotenoid supplementation was discontinued by subjects during the study. Serum retinol and provitamin A carotenoid concentrations; intake of preformed vitamin A, provitamin A, and fat; and body weight, fat mass, and lean mass were analyzed for correlations to 13C:12C-retinol. 13C:12C-Retinol decreased in the vegetable group after intervention (P = 0.050) and the correlation with provitamin A intake was approaching significance (P = 0.079). 13C:12C-Retinol did not change in the caloric reduction group (P = 0.43). 13C:12C-Retinol changes with the vitamin A source in the diet and can be used as a biomarker for increases in dietary provitamin A vegetable intake. PMID:19116317

  20. Scleroglucan biopolymer production, properties, and economics

    SciTech Connect

    Compere, A. L.; Griffith, W. L.

    1980-01-01

    Production and solution properties which may make scleroglucan polysaccharide economically advantageous for onsite production and use in tertiary oil recovery were investigated. Scleroglucan, which is similar in viscosity and shear thinning to xanthan, can be produced in a 3-day batch or 12 h continuous fermentation. Yield is nearly 50% based on input glucose. Gross biopolymer-biomass separation may be effected using microscreening, a low energy process, followed by polish filtration. Polymer flux may be improved by hydrolysis with an endolaminarinase from Rhizopus arrhizius QM 1032. Simple feedstock requirements and low growth pH, together with the difficulty of resuspending dried polymer, may encourage field biopolymer fermentation and use of purified culture broth.

  1. Active biopolymers confer fast reorganization kinetics.

    PubMed

    Swanson, Douglas; Wingreen, Ned S

    2011-11-18

    Many cytoskeletal biopolymers are "active," consuming energy in large quantities. In this Letter, we identify a fundamental difference between active polymers and passive, equilibrium polymers: for equal mean lengths, active polymers can reorganize faster than equilibrium polymers. We show that equilibrium polymers are intrinsically limited to linear scaling between mean lifetime (or mean first-passage time, or MFPT) and mean length, MFPT∼, by analogy to 1D Potts models. By contrast, we present a simple active-polymer model that improves upon this scaling, such that MFPT∼(1/2). Since, to be biologically useful, structural biopolymers must typically be many monomers long yet respond dynamically to the needs of the cell, the difference in reorganization kinetics may help to justify the active polymers' greater energy cost.

  2. Changes in Natural Abundance Carbon Stable isotopes of Human Blood and Saliva After 24 Days of Controlled Carbohydrate Supplementation

    NASA Astrophysics Data System (ADS)

    Kraft, R. A.; Jahren, A. H.; Baer, D. J.; Caballero, B.

    2008-12-01

    the δ13C value of their blood and saliva relative to baseline: blood clot was enriched by 0.27‰; blood serum by 0.50‰ and saliva by 1.12‰. We believe this overall enrichment resulted from a 13C-enriched bulk diet (δ13C = - 20.42‰) relative to the subjects free-living diet. Evidence for this derives from inspection of foods within the bulk diet provided, compared to published profiles of the typical American diet. We will discuss possible complicating factors, such as differential absorption and metabolism of the supplements according to solubility and caloric value. These results are encouraging for the development of a δ13C blood serum biomarker that, in the company of other tests, could be used to indicate a change in carbohydrate intake. Bray, G.A., Nielsen, S.J. and Popkin, B.M., 2004. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. American Journal of Clinical Nutrition, 79: 537-543. Havel, P.J., 2005. Dietary fructose: Implications for dysregulation of energy homeostasis and lipid/carbohydrate metabolism. Nutrition Reviews, 63(5): 133-157. Tilman D., 1998. The greening of the green revolution. Nature, 396:211-212.

  3. "Practical" Electrospinning of Biopolymers in Ionic Liquids.

    PubMed

    Shamshina, Julia L; Zavgorodnya, Oleksandra; Bonner, Jonathan R; Gurau, Gabriela; Di Nardo, Thomas; Rogers, Robin D

    2017-01-10

    To address the need to scale up technologies for electrospinning of biopolymers from ionic liquids to practical volumes, a setup for the multi-needle electrospinning of chitin using the ionic liquid 1-ethyl-3-methylimidazolium acetate, [C2 mim]-[OAc], was designed, built, and demonstrated. Materials with controllable and high surface area were prepared at the nanoscale using ionic-liquid solutions of high-molecular-weight chitin extracted with the same ionic liquid directly from shrimp shells.

  4. Earthworm eco-physiological characteristics and quantification of earthworm feeding in vermifiltration system for sewage sludge stabilization using stable isotopic natural abundance.

    PubMed

    Li, Xiaowei; Xing, Meiyan; Yang, Jian; Dai, Xiaohu

    2014-07-15

    Previous studies showed that the presence of earthworm improves treatment performance of vermifilter (VF) for sewage sludge stabilization, but earthworm eco-physiological characteristics and effects in VF were not fully investigated. In this study, earthworm population, enzymatic activity, gut microbial community and stable isotopic abundance were investigated in the VF. Results showed that biomass, average weight, number and alkaline phosphatase activity of the earthworms tended to decrease, while protein content and activities of peroxidase and catalase had an increasing tendency as the VF depth. Earthworm gut microbial communities were dominated by Gammaproteobacteria, and the percentages arrived to 76-92% of the microbial species detected. (15)N and (13)C natural abundance of the earthworms decreased with operation time, and increased as the VF depth. Quantitative analysis using δ(15)N showed that earthworm feeding and earthworm-microorganism interaction were responsible for approximately 21% and 79%, respectively, of the enhanced volatile suspended solid reduction due to the presence of earthworm. The finding provides a quantitative insight into how earthworms influence on sewage sludge stabilization in vermifiltration system.

  5. Molecular Entanglement and Electrospinnability of Biopolymers

    PubMed Central

    Kong, Lingyan; Ziegler, Gregory R.

    2014-01-01

    Electrospinning is a fascinating technique to fabricate micro- to nano-scale fibers from a wide variety of materials. For biopolymers, molecular entanglement of the constituent polymers in the spinning dope was found to be an essential prerequisite for successful electrospinning. Rheology is a powerful tool to probe the molecular conformation and interaction of biopolymers. In this report, we demonstrate the protocol for utilizing rheology to evaluate the electrospinnability of two biopolymers, starch and pullulan, from their dimethyl sulfoxide (DMSO)/water dispersions. Well-formed starch and pullulan fibers with average diameters in the submicron to micron range were obtained. Electrospinnability was evaluated by visual and microscopic observation of the fibers formed. By correlating the rheological properties of the dispersions to their electrospinnability, we demonstrate that molecular conformation, molecular entanglement, and shear viscosity all affect electrospinning. Rheology is not only useful in solvent system selection and process optimization, but also in understanding the mechanism of fiber formation on a molecular level. PMID:25226274

  6. Using natural 15N abundances to trace the fate of waste-derived nitrogen in forest ecosystems: New Zealand case studies.

    PubMed

    Wang, H; Magesan, G N; Clinton, P W; Lavery, J M

    2005-03-01

    Treatment of wastewater generally results in elevated natural 15N abundance (delta15N) in the effluent and sludges. For example, high delta15N values are found in treated sewage effluent, biosolids, and other wastes that are commonly applied to land. In contrast, N deficient coniferous forest soils usually have a low delta15N. When wastes with high delta15N values are applied to land, their distinctive delta15N signature can potentially be used to trace the fate of waste-derived N in the ecosystem. In this paper, we provide an overview of the use of delta15N in land application of wastes, including New Zealand case studies on tracing nitrogen in forest ecosystems.

  7. Hydrogels from biopolymer hybrid for biomedical, food, and functional food applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hybrid hydrogels from biopolymers have been applied for various indications across a wide range of biomedical, pharmaceutical, and functional food industries. In particular, hybrid hydrogels synthesized from two biopolymers have attracted increasing attention. The inclusion of a second biopolymer st...

  8. Determination of microbial carbon sources and cycling during remediation of petroleum hydrocarbon impacted soil using natural abundance (14)C analysis of PLFA.

    PubMed

    Cowie, Benjamin R; Greenberg, Bruce M; Slater, Gregory F

    2010-04-01

    In a petroleum impacted land-farm soil in Sarnia, Ontario, compound-specific natural abundance radiocarbon analysis identified biodegradation by the soil microbial community as a major pathway for hydrocarbon removal in a novel remediation system. During remediation of contaminated soils by a plant growth promoting rhizobacteria enhanced phytoremediation system (PEPS), the measured Delta(14)C of phospholipid fatty acid (PLFA) biomarkers ranged from -793 per thousand to -897 per thousand, directly demonstrating microbial uptake and utilization of petroleum hydrocarbons (Delta(14)C(PHC) = -1000 per thousand). Isotopic mass balance indicated that more than 80% of microbial PLFA carbon was derived from petroleum hydrocarbons (PHC) and a maximum of 20% was obtained from metabolism of more modern carbon sources. These PLFA from the contaminated soils were the most (14)C-depleted biomarkers ever measured for an in situ environmental system, and this study demonstrated that the microbial community in this soil was subsisting primarily on petroleum hydrocarbons. In contrast, the microbial community in a nearby uncontaminated control soil maintained a more modern Delta(14)C signature than total organic carbon (Delta(14)C(PLFA) = +36 per thousand to -147 per thousand, Delta(14)C(TOC) = -148 per thousand), indicating preferential consumption of the most modern plant-derived fraction of soil organic carbon. Measurements of delta(13)C and Delta(14)C of soil CO(2) additionally demonstrated that mineralization of PHC contributed to soil CO(2) at the contaminated site. The CO(2) in the uncontaminated control soil exhibited substantially more modern Delta(14)C values, and lower soil CO(2) concentrations than the contaminated soils, suggesting increased rates of soil respiration in the contaminated soils. In combination, these results demonstrated that biodegradation in the soil microbial community was a primary pathway of petroleum hydrocarbon removal in the PEPS system. This study

  9. Strong Coupling of Shoot Assimilation and Soil Respiration during Drought and Recovery Periods in Beech As Indicated by Natural Abundance δ(13)C Measurements.

    PubMed

    Blessing, Carola H; Barthel, Matti; Gentsch, Lydia; Buchmann, Nina

    2016-01-01

    Drought down-regulates above- and belowground carbon fluxes, however, the resilience of trees to drought will also depend on the speed and magnitude of recovery of these above- and belowground fluxes after re-wetting. Carbon isotope composition of above- and belowground carbon fluxes at natural abundance provides a methodological approach to study the coupling between photosynthesis and soil respiration (SR) under conditions (such as drought) that influence photosynthetic carbon isotope discrimination. In turn, the direct supply of root respiration with recent photoassimilates will impact on the carbon isotope composition of soil-respired CO2. We independently measured shoot and soil CO2 fluxes of beech saplings (Fagus sylvatica L.) and their respective δ(13)C continuously with laser spectroscopy at natural abundance. We quantified the speed of recovery of drought stressed trees after re-watering and traced photosynthetic carbon isotope signal in the carbon isotope composition of soil-respired CO2. Stomatal conductance responded strongly to the moderate drought (-65%), induced by reduced soil moisture content as well as increased vapor pressure deficit. Simultaneously, carbon isotope discrimination decreased by 8‰, which in turn caused a significant increase in δ(13)C of recent metabolites (1.5-2.5‰) and in δ(13)C of SR (1-1.5‰). Generally, shoot and soil CO2 fluxes and their δ(13)C were in alignment during drought and subsequent stress release, clearly demonstrating a permanent dependence of root respiration on recently fixed photoassimilates, rather than on older reserves. After re-watering, the drought signal persisted longer in δ(13)C of the water soluble fraction that integrates multiple metabolites (soluble sugars, amino acids, organic acids) than in the neutral fraction which represents most recently assimilated sugars or in the δ(13)C of SR. Nevertheless, full recovery of all aboveground physiological variables was reached within 4 days - and

  10. Estimation of phenotypic variability in symbiotic nitrogen fixation ability of common bean under drought stress using (15)N natural abundance in grain.

    PubMed

    Polania, Jose; Poschenrieder, Charlotte; Rao, Idupulapati; Beebe, Stephen

    2016-09-01

    Common bean (Phaseolus vulgaris L.) is the most important food legume, cultivated by small farmers and is usually exposed to unfavorable conditions with minimum use of inputs. Drought and low soil fertility, especially phosphorus and nitrogen (N) deficiencies, are major limitations to bean yield in smallholder systems. Beans can derive part of their required N from the atmosphere through symbiotic nitrogen fixation (SNF). Drought stress severely limits SNF ability of plants. The main objectives of this study were to: (i) test and validate the use of (15)N natural abundance in grain to quantify phenotypic differences in SNF ability for its implementation in breeding programs of common bean with bush growth habit aiming to improve SNF, and (ii) quantify phenotypic differences in SNF under drought to identify superior genotypes that could serve as parents. Field studies were conducted at CIAT-Palmira, Colombia using a set of 36 bean genotypes belonging to the Middle American gene pool for evaluation in two seasons with two levels of water supply (irrigated and drought stress). We used (15)N natural abundance method to compare SNF ability estimated from shoot tissue sampled at mid-pod filling growth stage vs. grain tissue sampled at harvest. Our results showed positive and significant correlation between nitrogen derived from the atmosphere (%Ndfa) estimated using shoot tissue at mid-pod filling and %Ndfa estimated using grain tissue at harvest. Both methods showed phenotypic variability in SNF ability under both drought and irrigated conditions and a significant reduction in SNF ability was observed under drought stress. We suggest that the method of estimating Ndfa using grain tissue (Ndfa-G) could be applied in bean breeding programs to improve SNF ability. Using this method of Ndfa-G, we identified four bean lines (RCB 593, SEA 15, NCB 226 and BFS 29) that combine greater SNF ability with greater grain yield under drought stress and these could serve as potential

  11. Relationships between soil nitrogen dynamics and natural 15N-abundance in plant foliage from the Great Smoky Mountains National Park

    SciTech Connect

    Garten Jr, Charles T; Van Miegroet, H. M.

    1994-08-01

    We tested the hypothesis that naturally occurring nitrogen (N) isotope ratios in foliage (from plants that do not symbiotically fix atmospheric N{sub 2}) are an indicator of soil N dynamics in forests. Replicate plots were established at eight locations ranging in elevation from 615 to 1670 m in Great Smoky Mountains National Park in eastern Tennessee, U.S.A. The locations selected ranged from N-poor (low-elevation) to N-rich (high-elevation) forest stands. Soils were sampled in June 1992; plants, forest floors, and upper mineral soils were sampled in August 1992. Net N mineralization and net nitrification potentials for surface mineral soils and organic matter layers at each site were determined by aerobic laboratory incubations. Soils and organic layers from high-elevation sites had greater net N mineralization and nitrification potentials than soils from low-elevation sites. There were significant (P {le} 0.05) differences between study sites in soil {sup 15}N abundance. Therefore, we examined correlations between measures of soil N availability and both mean foliar {delta}{sup 15}N values and mean enrichment factors ({var_epsilon}{sub p-s} = {delta}{sup 15}N{sub leaf} - {delta}{sup 15}N{sub soil}). In evergreens, maples, and ferns, mean foliar {delta}{sup 15}N values and mean enrichment factors were positively correlated with net N mineralization and net nitrification potentials in soil. The observed relationships between natural {sup 15}N abundance in plant leaves and soil N availability were explained by a simple model of soil N dynamics. The model predicts how the isotopic composition of plant N is affected by the following factors: (i) varying uptake of soil NH{sub 4}-N and NO{sub 3}-N, (ii) the isotopic composition of different soil N pools, and (iii) relative rates of soil N transformations.

  12. Decomposition and transformation of cutin and cutan biopolymers in soils: effect on their sorptive capabilities

    NASA Astrophysics Data System (ADS)

    Shechter, M.; Chefetz, B.

    2009-04-01

    Plant cuticle materials, especially the highly aliphatic biopolymers cutin and cutan, have been reported as highly efficient natural sorbents. The objective of this study was to examine the effects of decomposition on their sorption behavior with naphthol and phenanthrene. The level of cutin and cutan was reduced by 15 and 27% respectively during the first 3 mo of incubation. From that point, the level of the cutan did not change, while the level of the cutin continued to decrease up to 32% after 20 mo. 13C NMR analysis suggested transformation of cutan mainly within its alkyl-C structure which are assigned as crystalline moieties. Cutin, however, did not exhibit significant structure changes with time. The level of humic-like substances increased due to cutin decomposition but was not influenced in the cutan system after 20 mo of incubation. This indicates that the cutin biopolymer has been decomposed and transformed into humic-like substances, whereas the cutan was less subject to transformation. Decomposition affected sorption properties in similar trends for both cutin and cutan. The Freundlich capacity coefficients (KFOC) of naphthol were much lower than phenanthrene and were less influenced by the decomposition, whereas with phenanthrene KFOC values increased significantly with time. Naphthol exhibited non-linear isotherms; and nonlinearity was decreased with incubation time. In contrast, phenanthrene isotherms were more linear and showed only moderate change with time. The decrease in the linearity of naphthol isotherms might relate to the transformation of the sorption sites due to structural changes in the biopolymers. However, with phenanthrene, these changes did not affect sorption linearity but increased sorption affinities mainly for cutan. This is probably due to decomposition of the rigid alkyl-C moieties in the cutan biopolymer. Our data suggest that both biopolymers were relatively stable in the soil for 20 mo. Cutan is less degradable than cutin

  13. Rheological and Tribological Properties of Complex Biopolymer Solutions

    NASA Astrophysics Data System (ADS)

    Klossner, Rebecca Reese

    2011-12-01

    little impact on the actual aggregation process. Additionally, the relationship between the rheology and tribology of the SFM was studied through a series of nanoscratch tests using a Hysitron nanoindenter. The nanoindenter has the ability to measure both normal and lateral forces simultaneously, which gives an indication of the lubricity of the solution. The coefficient of friction values for solutions of varying protein concentrations were determined by dividing the lateral force by the normal force. Tribological testing of the synovial fluid model and modified solutions were carried out on spin-cast polyethylene and ultra high molecular weight polyethylene sheets. At lower molecular weight substrates, the film thickness limited the validity of the generated data, and with higher molecular weight surfaces, surface roughness effects were found to dominate the tribological response. Finally, the addition of HCQ does not have a large impact on the tribological data, indicating that the anti-inflammatory drug does not significantly impact the lubrication properties within the synovial fluid model. Finally, additional rheological studies of biopolymer solutions were conducted in which solutions containing chitosan, a natural, bioactive polymer, were characterized to determine their fitness for the electropsinning process. Chitosan fibers are difficult to electrospin, and through these studies, the entanglement concentration, a critical parameter for electrospinning, was determined. The generated rheological data provided a means to predict the morphology of the resulting nanofibers, and aspects of the difficulty in electrospinning chitosan were revealed.

  14. Analysis of the structure of synthetic and natural melanins by solid-phase

    SciTech Connect

    Duff, G.A.; Roberts, J.E.; Foster, N.

    1988-09-06

    The structures of one synthetic and two natural melanins are examined by solid-state NMR using cross polarization, magic angle sample spinning, and high-power proton decoupling. The structural features of synthetic dopa malanin are compared to those of melanin from malignant melanoma cells grown in culture and sepia melanin from squid ink. Natural abundance /sup 13/C and /sup 15/N spectra show resonances consistent with known pyrrolic and indolic structures within the heterogeneous biopolymer; /sup 13/C spectra indicate the presence of aliphatic residues in all three materials. These solid-phase experiments illustrate the promise of solid-phase NMR for elucidating structural from insoluble biomaterials.

  15. Final Technical Report for 'Investigations of the Role of Protozoa in Transformations of Marine Biopolymers using Phaeocytis Polymer Gels as a Model'

    SciTech Connect

    Lessard, Evelyn

    2003-04-01

    protists are able to use the polymer for nutrition and growth. This is the first demonstration of the ingestion and utilization of a natural marine biopolymer by protists. We also isolated three bacterial strains from our Phaeocystis cultures. All three bacterial strains were capable of growing solely on the polymer gels produced by Phaeocystis without added inorganic nitrogen sources. We used the bacterial and protist strains to investigate degradation and alterations (size, chemical composition) of Phaeocystis polymer gels by bacteria alone and in the presence of protists. In a typical experiment, bacterial abundance in the presence of protists was reduced to one third of that in the control due to grazing, but the degradation rate was about the same. This indicates either that grazing by the protist somehow enhanced the per cell rate of bacterial degradation and/or the protist was ingesting polymer directly. Residual polymer remained after weeks, but the mean the mean diameter of the polymers were shortened considerably to ca. 200 nm. These results, along with other lines of evidence, suggest that it may be the length of polymer that limits degradation, which has important implications for the large pool of refractory DOM in the oceans. Chemical analyses indicated that the polymers are carbohydrate-rich and that the nitrogen is not proteinaceous, but most likely in the form of low molecular weight compounds such as amino sugars or sialic acid, and that they had a surprisingly low C:N ratios (<9). Extracellular polymers may therefore provide a nutritional substrate for bacteria and protists without the need for other sources of nitrogen in nature.

  16. Lipid functionalized biopolymers: A review.

    PubMed

    Qurat-Ul-Ain; Zia, Khalid Mahmood; Zia, Fatima; Ali, Muhammad; Rehman, Saima; Zuber, Mohammad

    2016-12-01

    Lipids are the main source of energy and widely used for various applications. In this review, the modification of lipids by using them in combination with other biomaterials like natural and synthetic polymers is elaborated. These new blends have characteristic features of both polymers and are characterized by different techniques (NMR, DSC, TGA, IR and Raman spectroscopy etc.) to understand their structure, properties and functional behavior. Lipids are hydrophobic, have anti-oxidant and anti-bacterial properties and thus impart hydrophobicity and flexibility to the polymers. While the polymers, on the other hand, make the lipids tougher. Properties of few polymers such as starch, polyethylene protein and chitosan that have brittleness, low combustion rate and hydrophobicity, are improved by incorporation of lipids ultimately increased their flexibility, combustion rate and hydrophobicity respectively. This review article is also focused on emerging fields for the applications of these composite materials. The most notable application of composite materials are in the field of paint industry.

  17. A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess

    NASA Astrophysics Data System (ADS)

    Zhang, Junsong; Cui, Lishan; Jiang, Daqiang; Liu, Yinong; Hao, Shijie; Ren, Yang; Han, Xiaodong; Liu, Zhenyang; Wang, Yunzhi; Yu, Cun; Huan, Yong; Zhao, Xinqing; Zheng, Yanjun; Xu, Huibin; Ren, Xiaobing; Li, Xiaodong

    2015-02-01

    The design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature's armor, is renowned for its unusual combination of strength and toughness. Nature's wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer's deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memory alloy to transcribe the ``J-curve'' mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti3Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials.

  18. Molecular Investigation of the Short-term Sequestration of Natural Abundance 13C -labelled Cow Dung in the Surface Horizons of a Temperate Grassland Soil

    NASA Astrophysics Data System (ADS)

    Dungait, J.; Bol, R.; Evershed, R. P.

    2004-12-01

    An adequate understanding of the carbon (C) sequestration potential of grasslands requires that the quantity and residence times of C inputs be measured. Herbivore dung is largely comprised of plant cell wall material, a significant source of stable C in intensively grazed temperate grassland ecosystems that contributes to the soil carbon budget. Our work uses compound-specific isotope analysis to identify the pattern of input of dung-derived compounds from natural abundance 13C/-labelled cow dung into the surface horizons of a temperate grassland soil over one year. C4 dung (δ 13C \\-12.6 ‰ ) from maize fed cows was applied to a temperate grassland surface (δ 13C \\-29.95 ‰ ) at IGER-North Wyke (Devon, UK), and dung remains and soil cores beneath the treatments collected at ŧ = 7, 14, 28, 56, 112, 224 and 372 days. Bulk dung carbon present in the 0\\-1 cm and 1\\-5 cm surface horizons of a grassland soil over one year was estimated using Δ 13C between C4 dung and C3 dung, after Bol {\\et al.} (2000). The major biochemical components of dung were quantified using proximate forage fibre analyses, after Goering and Van Soest (1970) and identified using `wet' chemical and GC-MS methods. Plant cell wall polysaccharides and lignin were found to account for up to 67 {%} of dung dry matter. Hydrolysed polysaccharides were prepared as alditol acetates for analyses (after Docherty {\\et al.}, 2001), and a novel application of an off-line pyrolysis method applied to measure lignin-derived phenolic compounds (after Poole & van Bergen, 2002). This paper focuses on major events in the incorporation of dung carbon, estimated using natural abundance 13C&-slash;labelling technique. This revealed a major bulk input of dung carbon after a period of significant rainfall with a consequent decline in bulk soil δ 13C values until the end of the experiment (Dungait {\\et al.}, submitted). Findings will be presented revealing contribution of plant cell wall polysaccharides and

  19. Load sharing in the growth of bundled biopolymers

    NASA Astrophysics Data System (ADS)

    Wang, Ruizhe; Carlsson, A. E.

    2014-11-01

    To elucidate the nature of load sharing in the growth of multiple biopolymers, we perform stochastic simulations of the growth of biopolymer bundles against obstacles under a broad range of conditions and varying assumptions. The obstacle motion due to thermal fluctuations is treated explicitly. We assume the ‘perfect Brownian ratchet’ model, in which the polymerization rate equals the free-filament rate as soon as the filament-obstacle distance exceeds the monomer size. Accurate closed-form formulas are obtained for the case of a rapidly moving obstacle. We find the following: (1) load sharing is usually sub-perfect in the sense that polymerization is slower than for a single filament carrying the same average force; (2) the sub-perfect behavior becomes significant at a total force proportional to the logarithm or the square root of the number of filaments, depending on the alignment of the filaments; (3) for the special case of slow barrier diffusion and low opposing force, an enhanced obstacle velocity for an increasing number of filaments is possible; (4) the obstacle velocity is very sensitive to the alignment of the filaments in the bundle, with a staggered alignment being an order of magnitude faster than an unstaggered one at forces of only 0.5 pN per filament for 20 filaments; (5) for large numbers of filaments, the power is maximized at a force well below 1 pN per filament; (6) for intermediate values of the obstacle diffusion coefficient, the shape of the force velocity relation is very similar to that for rapid obstacle diffusion.

  20. Fine Structure of Starch-Clay Composites as Biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Midsol 50 wheat starch and 5% Cloisite clay with or without the addition of glycerin were used to prepare biopolymers in a twin-screw extruder. Early trials of sectioning the unembedded biopolymer resulted in the immediate absorption of water and subsequent dissolution of the sample due to the the ...

  1. Using biopolymers to remove heavy metals from soil and water

    SciTech Connect

    Krishnamurthy, S.; Frederick, R.M.

    1993-11-19

    Chemical remediation of soil may involve the use of harsh chemicals that generate waste streams, which may adversely affect the soil's integrity and ability to support vegetation. This article reviews the potential use of benign reagents, such as biopolymers, to extract heavy metals. The biopolymers discussed are chitin and chitosan, modified starch, cellulose, and polymer-containing algae. (Copyright (c) Remediation 1994.)

  2. Formulation of indomethacin emulsion using biopolymer of Prunus avium.

    PubMed

    Verma, Shivangi; Dabral, Prashant; Rana, Vinod; Upadhaya, Kumud; Bhardwaj

    2012-03-01

    The aim of the investigation was to formulate Indomethacin Emulsion using Bio-polymer as Emulsifier. Different batches of emulsions were prepared by varying concentration of biopolymer prunus avium. Based evaluation of the prepared polymers, a conclusion can be drawn that in the Prunus avium bio-material can serve as a promising film forming agent for formulating various drug.

  3. Insights into the sorption properties of cutin and cutan biopolymers.

    PubMed

    Shechter, Michal; Chefetz, Benny

    2008-02-15

    Plant cuticles have been reported as highly efficient sorbents for organic compounds. The objective of this study was to elucidate the sorption and desorption behavior of polar and nonpolar organic compounds with the major structural components of the plant cuticle: the biopolymers cutin and cutan. The sorption affinity values of the studied compounds followed the order: phenanthrene > atrazine > chlorotoluron > carbamazepine. A higher sorption affinity of phenanthrene and atrazine to cutin was probably due to the higher level of amorphous paraffinic carbon in this biopolymer. Phenanthrene exhibited reversible sorption behavior and a high ratio of organic-carbon-normalized distribution coefficient (Koc) to carbon-normalized octanol-water partitioning coefficients (Kowc) with both biopolymers. This suggests that both biopolymers provide phenanthrene with a partition medium for hydrophobic interactions with the flexible long alkyl-chain moieties of the biopolymers. The low Koc/Kowc ratios obtained for the polar sorbates suggest that the polar sites in the biopolymers are not accessible for sorption interactions. Atrazine and carbamazepine exhibited sorption-desorption hysteresis with both sorbents, indicating that both sorbates interact with cutin and cutan via both hydrophobic and specific interactions. In general, the sorptive properties of the studied biopolymers were similar, signifying that the active sorption sites are similar even though the biopolymers exhibit different properties.

  4. Biopolymer-supported ionic-liquid-phase ruthenium catalysts for olefin metathesis.

    PubMed

    Clousier, Nathalie; Filippi, Alexandra; Borré, Etienne; Guibal, Eric; Crévisy, Christophe; Caijo, Fréderic; Mauduit, Marc; Dez, Isabelle; Gaumont, Annie-Claude

    2014-04-01

    Original ruthenium supported ionic liquid phase (SILP) catalysts based on alginates as supports were developed for olefin metathesis reactions. The marine biopolymer, which fulfills most of the requisite properties for a support such as widespread abundance, insolubility in the majority of organic solvents, a high affinity for ionic liquids, high chemical stability, biodegradability, low cost, and easy processing, was impregnated by [bmim][PF6 ] containing an ionically tagged ruthenium catalyst. These biosourced catalysts show promising performances in ring-closing metathesis (RCM) and cross-metathesis (CM) reactions, with a high level of recyclability and reusability combined with a good reactivity.

  5. Strong Coupling of Shoot Assimilation and Soil Respiration during Drought and Recovery Periods in Beech As Indicated by Natural Abundance δ13C Measurements

    PubMed Central

    Blessing, Carola H.; Barthel, Matti; Gentsch, Lydia; Buchmann, Nina

    2016-01-01

    Drought down-regulates above- and belowground carbon fluxes, however, the resilience of trees to drought will also depend on the speed and magnitude of recovery of these above- and belowground fluxes after re-wetting. Carbon isotope composition of above- and belowground carbon fluxes at natural abundance provides a methodological approach to study the coupling between photosynthesis and soil respiration (SR) under conditions (such as drought) that influence photosynthetic carbon isotope discrimination. In turn, the direct supply of root respiration with recent photoassimilates will impact on the carbon isotope composition of soil-respired CO2. We independently measured shoot and soil CO2 fluxes of beech saplings (Fagus sylvatica L.) and their respective δ13C continuously with laser spectroscopy at natural abundance. We quantified the speed of recovery of drought stressed trees after re-watering and traced photosynthetic carbon isotope signal in the carbon isotope composition of soil-respired CO2. Stomatal conductance responded strongly to the moderate drought (-65%), induced by reduced soil moisture content as well as increased vapor pressure deficit. Simultaneously, carbon isotope discrimination decreased by 8‰, which in turn caused a significant increase in δ13C of recent metabolites (1.5–2.5‰) and in δ13C of SR (1–1.5‰). Generally, shoot and soil CO2 fluxes and their δ13C were in alignment during drought and subsequent stress release, clearly demonstrating a permanent dependence of root respiration on recently fixed photoassimilates, rather than on older reserves. After re-watering, the drought signal persisted longer in δ13C of the water soluble fraction that integrates multiple metabolites (soluble sugars, amino acids, organic acids) than in the neutral fraction which represents most recently assimilated sugars or in the δ13C of SR. Nevertheless, full recovery of all aboveground physiological variables was reached within 4 days – and within 7

  6. Chitosan biopolymer for fuel cell applications.

    PubMed

    Ma, Jia; Sahai, Yogeshwar

    2013-02-15

    Fuel cell is an electrochemical device which converts chemical energy stored in a fuel into electrical energy. Fuel cells have been receiving attention due to its potential applicability as a good alternative power source. Recently, cost-effective and eco-friendly biopolymer chitosan has been extensively studied as a material for membrane electrolytes and electrodes in low to intermediate temperature hydrogen polymer electrolyte fuel cell, direct methanol fuel cell, alkaline fuel cell, and biofuel cell. This paper reviews structure and property of chitosan with respect to its applications in fuel cells. Recent achievements and prospect of its applications have also been included.

  7. Strong, Thermally Superinsulating Biopolymer-Silica Aerogel Hybrids by Cogelation of Silicic Acid with Pectin.

    PubMed

    Zhao, Shanyu; Malfait, Wim J; Demilecamps, Arnaud; Zhang, Yucheng; Brunner, Samuel; Huber, Lukas; Tingaut, Philippe; Rigacci, Arnaud; Budtova, Tatiana; Koebel, Matthias M

    2015-11-23

    Silica aerogels are excellent thermal insulators, but their brittle nature has prevented widespread application. To overcome these mechanical limitations, silica-biopolymer hybrids are a promising alternative. A one-pot process to monolithic, superinsulating pectin-silica hybrid aerogels is presented. Their structural and physical properties can be tuned by adjusting the gelation pH and pectin concentration. Hybrid aerogels made at pH 1.5 exhibit minimal dust release and vastly improved mechanical properties while remaining excellent thermal insulators. The change in the mechanical properties is directly linked to the observed "neck-free" nanoscale network structure with thicker struts. Such a design is superior to "neck-limited", classical inorganic aerogels. This new class of materials opens up new perspectives for novel silica-biopolymer nanocomposite aerogels.

  8. Natural abundance 17O, 6Li NMR and molecular modeling studies of the solvation structures of lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane liquid electrolytes

    SciTech Connect

    Wan, Chuan; Hu, Mary Y.; Borodin, Oleg; Qian, Jiangfeng; Qin, Zhaohai; Zhang, Ji-Guang; Hu, Jian Zhi

    2016-03-01

    Natural abundance 17O and 6Li NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li+ at various concentrations of LiFSI in DME electrolytes in an effort to solve this puzzle. It was found that the chemical shifts of both 17O and 6Li changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME)2 forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li+ and FSI- ion increases, but the association between Li+ and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li+(FSI-)2(DME), Li+2(FSI-)(DME)4 and (LiFSI)2(DME)3 become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li+ decreases, and the coordinated number of FSI- increases, which is in perfect accord with the DFT results. These results provide more insight on the fundamental mechanism on the very high CE of Li deposition in these electrolytes, especially at high current density conditions.

  9. Natural abundance 17O, 6Li NMR and molecular modeling studies of the solvation structures of lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane liquid electrolytes

    NASA Astrophysics Data System (ADS)

    Wan, Chuan; Hu, Mary Y.; Borodin, Oleg; Qian, Jiangfeng; Qin, Zhaohai; Zhang, Ji-Guang; Hu, Jian Zhi

    2016-03-01

    Natural abundance 17O and 6Li NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li+ at various concentrations of LiFSI in DME electrolytes. It was found that the chemical shifts of both 17O and 6Li changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME)2 forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li+ and FSI- ion increases, but the association between Li+ and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li+(FSI-)2(DME), Li+2(FSI-)(DME)4 and (LiFSI)2(DME)3 become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li+ decreases, and the coordinated number of FSI- increases, which is in perfect accord with the DFT results.

  10. Nitrogen input 15N-signatures are reflected in plant 15N natural abundances of N-rich tropical forest in China

    NASA Astrophysics Data System (ADS)

    Abdisa Gurmesa, Geshere; Lu, Xiankai; Gundersen, Per; Yunting, Fang; Mo, Jiangming

    2016-04-01

    In this study, we tested the measurement of natural abundance of 15N (δ15N) for its ability to assess changes in N cycling due to increased N deposition in two forest types; namely, an old-growth broadleaved forest and a pine forest, in southern China. We measured δ15N values of inorganic N in input and output fluxes under ambient N deposition, and N concentration and δ15N of major ecosystem compartments under ambient and increased N deposition. Our results showed that N deposition to the forests was 15N-depleted, and was dominated by NH4-N. Plants were 15N-depleted due to imprint from the 15N-depleted atmospheric N deposition. The old-growth forest had larger N concentration and was more 15N-enriched than the pine forest. Nitrogen addition did not significantly affect N concentration, but it significantly increased δ15N values of plants, and slightly more so in the pine forest, toward the 15N signature of the added N in both forests. The result indicates that the pine forest may rely more on the 15N-depleted deposition N. Soil δ15N values were slightly decreased by the N addition. Our result suggests that ecosystem δ15N is more sensitive to the changes in ecosystem N status and N cycling than N concentration in N-saturated sub-tropical forests.

  11. Natural abundance 15N NMR assignments delineate structural differences between intact and reactive-site hydrolyzed Cucurbita maxima trypsin inhibitor III.

    PubMed

    Krishnamoorthi, R; Nemmers, S; Tobias, B

    1992-06-15

    15N NMR assignments were made to the backbone amide nitrogen atoms at natural isotopic abundance of intact and reactive-site (Arg5-Ile6) hydrolyzed Cucurbita maxima trypsin inhibitor III (CMTI-III and CMTI-III*, respectively) by means of 2D proton-detected heteronuclear single bond chemical shift correlation (HSBC) spectroscopy, utilizing the previously made sequence-specific 1H NMR assignments (Krishnamoorthi et al. (1992) Biochemistry 31, 898-904). Comparison of the 15N chemical shifts of the two forms of the inhibitor molecule revealed significant changes not only for residues located near the reactive-site region, but also for those distantly located. Residues Cys3, Arg5, Leu7, Met8, Cys10, Cys16, Glu19, His25, Tyr27, Cys28 and Gly29 showed significant chemical shift changes ranging from 0.3 to 6.1 ppm, thus indicating structural perturbations that were transmitted throughout the molecule. These findings confirm the earlier conclusions based on 1H NMR investigations.

  12. Natural (15)N Abundance in Key Amino Acids from Lamb Muscle: Exploring a New Horizon in Diet Authentication and Assessment of Feed Efficiency in Ruminants.

    PubMed

    Cantalapiedra-Hijar, Gonzalo; Ortigues-Marty, Isabelle; Schiphorst, Anne-Marie; Robins, Richard J; Tea, Illa; Prache, Sophie

    2016-05-25

    Natural (15)N abundance (δ(15)N) varies between individual amino acids (AAs). We hypothesized that δ(15)N of nontransaminating and essential AAs ("source" AAs, such as phenylalanine) present in animal tissues could be used as a marker of dietary origin, whereas δ(15)N of transaminating AAs ("trophic" AAs, such as glutamic acid) could give more detailed insights into animal feed efficiency. Two diets based on dehydrated Lucerne pellets were tested in growing lambs, which promoted different feed efficiencies. No dietary effects were noted on δ(15)N of any AAs analyzed in lamb muscle. In addition, δ(15)N of phenylalanine was unexpectedly similar to that of glutamic acid, suggesting that δ(15)N of AAs is significantly derived from the metabolism of the rumen microbiota and, thus, are not suited for diet authentication in ruminants. In contrast, the δ(15)N of transaminating AAs facilitates an improved prediction of animal feed efficiency compared to the classical isotopic bulk N analysis.

  13. Natural abundance 14N and 15N solid-state NMR of pharmaceuticals and their polymorphs

    SciTech Connect

    Veinberg, Stanislav L.; Johnston, Karen E.; Jaroszewicz, Michael J.; Kispal, Brianna M.; Mireault, Christopher R.; Kobayashi, Takeshi; Pruski, Marek; Schurko, Robert W.

    2016-06-08

    14N ultra-wideline (UW), 1H{15N} indirectly-detected HETCOR (idHETCOR) and 15N dynamic nuclear polarization (DNP) solid-state NMR (SSNMR) experiments, in combination with plane-wave density functional theory (DFT) calculations of 14N EFG tensors, were utilized to characterize a series of nitrogen-containing active pharmaceutical ingredients (APIs), including HCl salts of scopolamine, alprenolol, isoprenaline, acebutolol, dibucaine, nicardipine, and ranitidine. Here, a case study applying these methods for the differentiation of polymorphs of bupivacaine HCl is also presented. All experiments were conducted upon samples with naturally-abundant nitrogen isotopes. For most of the APIs, it was possible to acquire frequency-stepped UW 14N SSNMR spectra of stationary samples, which display powder patterns corresponding to pseudo-tetrahedral (i.e., RR'R"NH+ and RR'NH2+) or other (i.e., RNH2 and RNO2) nitrogen environments.

  14. Biopolymer from microbial assisted in situ hydrolysis of triglycerides and dimerization of fatty acids.

    PubMed

    Kavitha, V; Radhakrishnan, N; Madhavacharyulu, E; Sailakshmi, G; Sekaran, G; Reddy, B S R; Rajkumar, G Suseela; Gnanamani, Arumugam

    2010-01-01

    The present study demonstrates biopolymer production by in situ bio-based dimerization of fatty acids by microorganism isolated from marine sediments. Microbial isolate grown in Zobell medium in the presence of triglycerides for the period of 24-240 h at 37 degrees C, hydrolyze the applied triglycerides and sequentially dimerized the hydrolyzed products and subsequently polymerized and transformed to a biopolymer having appreciable adhesive properties. Physical (nature, odour, stickyness and tensile strength), chemical (instrumentation) and biochemical (cell free broth) methods of analyses carried out provided the hypotheses involved in the formation of the product as well as the nature of the product formed. Results revealed, lipolytic enzymes released during initial period of growth and the biosurfactant production during later period, respectively, hydrolyze the applied triglycerides and initiate the dimerization and further accelerated when the incubation period extended. The existence and the non-existence of in situ hydrolysis of various triglycerides followed by dimerization and polymerization and the mechanism of transformation of triglycerides to biopolymer are discussed in detail.

  15. Biopolymer based nanosystem for doxorubicin targeted delivery

    PubMed Central

    Csikós, Zsuzsanna; Kerekes, Krisztina; Fazekas, Erika; Kun, Sándor; Borbély, János

    2017-01-01

    This study describes formation of an actively and passively targeted, water-soluble drug delivery system (DDS) which contains doxorubicin (DOX). The system comprises two biocompatible and biodegradable polymers: poly-γ-glutamic acid (PGA) and chitosan (CH). Self-assembly of these biopolymers in aqueous medium results stable nanoparticles (NPs) with a hydrodynamic size of 80-150 nm and slightly negative surface charge. Folic acid (FA) was used as targeting agent bonded to the polyanion (PA) and also to the surface of the NPs. The NP’s physical stability, active targeting effect, cellular toxicity, release profile and in vivo anti-tumor efficacy were investigated. It was found that the targeted, self-assembled nanoparticles are stable at 4°C for several months, cause better in vitro toxicity effect on folate receptor (FR) positive cell lines than the doxorubicin or the non-targeted nanosystem and based on its release profile it is expected, that the nanosystem will remain stable during the circulation in the body. Pharmacodynamic studies demonstrated that the DOX-loaded nanoparticles can deliver greater tumor growth inhibition than the free drug molecules and the liposomal compound, with less general toxicity. It was observed that the overall survival is the main benefit of the biopolymer based drug delivery system.

  16. Molecular Biodynamers: Dynamic Covalent Analogues of Biopolymers.

    PubMed

    Liu, Yun; Lehn, Jean-Marie; Hirsch, Anna K H

    2017-02-21

    Constitutional dynamic chemistry (CDC) features the use of reversible linkages at both molecular and supramolecular levels, including reversible covalent bonds (dynamic covalent chemistry, DCC) and noncovalent interactions (dynamic noncovalent chemistry, DNCC). Due to its inherent reversibility and stimuli-responsiveness, CDC has been widely utilized as a powerful tool for the screening of bioactive compounds, the exploitation of receptors or substrates driven by molecular recognition, and the fabrication of constitutionally dynamic materials. Implementation of CDC in biopolymer science leads to the generation of constitutionally dynamic analogues of biopolymers, biodynamers, at the molecular level (molecular biodynamers) through DCC or at the supramolecular level (supramolecular biodynamers) via DNCC. Therefore, biodynamers are prepared by reversible covalent polymerization or noncovalent polyassociation of biorelevant monomers. In particular, molecular biodynamers, biodynamers of the covalent type whose monomeric units are connected by reversible covalent bonds, are generated by reversible polymerization of bio-based monomers and can be seen as a combination of biopolymers with DCC. Owing to the reversible covalent bonds used in DCC, molecular biodynamers can undergo continuous and spontaneous constitutional modifications via incorporation/decorporation and exchange of biorelevant monomers in response to internal or external stimuli. As a result, they behave as adaptive materials with novel properties, such as self-healing, stimuli-responsiveness, and tunable mechanical and optical character. More specifically, molecular biodynamers combine the biorelevant characters (e.g., biocompatibility, biodegradability, biofunctionality) of bioactive monomers with the dynamic features of reversible covalent bonds (e.g., changeable, tunable, controllable, self-healing, and stimuli-responsive capacities), to realize synergistic properties in one system. In addition, molecular

  17. Molecular Biodynamers: Dynamic Covalent Analogues of Biopolymers

    PubMed Central

    2017-01-01

    Conspectus Constitutional dynamic chemistry (CDC) features the use of reversible linkages at both molecular and supramolecular levels, including reversible covalent bonds (dynamic covalent chemistry, DCC) and noncovalent interactions (dynamic noncovalent chemistry, DNCC). Due to its inherent reversibility and stimuli-responsiveness, CDC has been widely utilized as a powerful tool for the screening of bioactive compounds, the exploitation of receptors or substrates driven by molecular recognition, and the fabrication of constitutionally dynamic materials. Implementation of CDC in biopolymer science leads to the generation of constitutionally dynamic analogues of biopolymers, biodynamers, at the molecular level (molecular biodynamers) through DCC or at the supramolecular level (supramolecular biodynamers) via DNCC. Therefore, biodynamers are prepared by reversible covalent polymerization or noncovalent polyassociation of biorelevant monomers. In particular, molecular biodynamers, biodynamers of the covalent type whose monomeric units are connected by reversible covalent bonds, are generated by reversible polymerization of bio-based monomers and can be seen as a combination of biopolymers with DCC. Owing to the reversible covalent bonds used in DCC, molecular biodynamers can undergo continuous and spontaneous constitutional modifications via incorporation/decorporation and exchange of biorelevant monomers in response to internal or external stimuli. As a result, they behave as adaptive materials with novel properties, such as self-healing, stimuli-responsiveness, and tunable mechanical and optical character. More specifically, molecular biodynamers combine the biorelevant characters (e.g., biocompatibility, biodegradability, biofunctionality) of bioactive monomers with the dynamic features of reversible covalent bonds (e.g., changeable, tunable, controllable, self-healing, and stimuli-responsive capacities), to realize synergistic properties in one system. In addition

  18. Effects of clear-cutting and soil preparation on natural 15N abundance in the soil and needles of two boreal conifer tree species.

    PubMed

    Sah, Shambu P; Ilvesniemi, Hannu

    2006-12-01

    This study presents the impacts of clear-cutting and site preparation on soil and needle 15N-fractionation of Scots pine (Pinus sylvestris, L.) and Norway spruce (Picea abies (L.), Karst). Three microsites on different methods of site preparation were used: (i) mound (broken O/E/B horizons piled upside down over undisturbed humus), (ii) deep (exposed C-horizon) and (iii) shallow (exposed E/B horizon). We found significant differences between species, between closed forest and clear-cuts as well as between different site preparations. For instance, in the context of interspecific variations, the mean needle nitrogen concentrations of both seedlings (1.15,+/-0.10 %) and mature (1.09,+/-0.07 %) pine trees were significantly higher compared to corresponding needle concentrations of seedlings (0.88,+/-0.06 %) and mature trees (0.79,+/-0.02 %) of spruce. Similarly, we observed significantly more 15N-enriched needles of mature spruces (-4.0,+/-0.20 per thousand) as well as of seedlings (-5.0,+/-0.11 per thousand) relative to that of mature pine needles (-5.6,+/-0.10 per thousand) and seedlings (-6.0,+/-0.31 per thousand). These variations were assumed to be caused by the variation in mycorrhizal associations between the species. We assume that the proportion of mycorrhizal N-uptake of pines might have been larger than that of spruce. Regarding the clear-cut effects on N and 15N of both tree species, we observed that, in the mature natural stand, needle N concentrations of both pine (1.09,+/-0.07 %) and spruce (0.79,+/-0.02 %) tree species did not change significantly after clear-cutting (pine: 1.01,+/-0.06 %; spruce: 0.74,+/-0.04 % ). However, clear-cutting resulted in the significant increase in needle 15N natural abundance of both pine (-2.70,+/-0.06 per thousand) and spruce (-2.09,+/-0.05 per thousand) in comparison to that of natural stand (pine:-5.60,+/-0.10 per thousand; spruce:-4.00,+/-0.20 per thousand), which is assumed to be due to the increased level of

  19. Natural abundances of 15N and 13C in leaves of some N2-fixing and non-N2-fixing trees and shrubs in Syria.

    PubMed

    Kurdali, F; Al-Shamma'a, M

    2009-09-01

    A survey study was conducted on man-made plantations located at two different areas in the arid region of Syria to determine the variations in natural abundances of the (15)N and (13)C isotopes in leaves of several woody legume and non-legume species, and to better understand the consequence of such variations on nitrogen fixation and carbon assimilation. In the first study area (non-saline soil), the delta(15)N values in four legume species (Acacia cyanophylla,-1.73 per thousand Acacia farnesiana,-0.55 per thousand Prosopis juliflora,-1.64 per thousand; and Medicago arborea,+1.6 \\textperthousand) and one actinorhizal plant (Elaeagnus angustifolia,-0.46 to-2.1 per thousand) were found to be close to that of the atmospheric value pointing to a major contribution of N(2) fixing in these species; whereas, delta(15)N values of the non-fixing plant species were highly positive. delta(13)C per thousand; in leaves of the C3 plants were found to be affected by plant species, ranging from a minimum of-28.67 per thousand; to a maximum of-23 per thousand. However, they were relatively similar within each plant species although they were grown at different sites. In the second study area (salt affected soil), a higher carbon discrimination value (Delta(13)C per thousand) was exhibited by P. juliflora, indicating that the latter is a salt tolerant species; however, its delta(15)N was highly positive (+7.03 per thousand) suggesting a negligible contribution of the fixed N(2). Hence, it was concluded that the enhancement of N(2) fixation might be achieved by selection of salt-tolerant Rhizobium strains.

  20. Carbon-13 natural abundance signatures of long-chain fatty acids to determinate sediment origin: A case study in northeast Austria

    NASA Astrophysics Data System (ADS)

    Mabit, Lionel; Gibbs, Max; Meusburger, Katrin; Toloza, Arsenio; Resch, Christian; Klik, Andreas; Swales, Andrew; Alewell, Christine

    2016-04-01

    - Several recently published information from scientific research have highlighted that compound-specific stable isotope (CSSI) signatures of fatty acids (FAs) based on the measurement of carbon-13 natural abundance signatures showed great promises to identify sediment origin. The authors have used this innovative isotopic approach to investigate the sources of sediment in a three hectares Austrian sub-watershed (i.e. Mistelbach). Through a previous study using the Cs-137 technique, Mabit et al. (Geoderma, 2009) reported a local maximum sedimentation rate reaching 20 to 50 t/ha/yr in the lowest part of this watershed. However, this study did not identify the sources. Subsequently, the deposited sediment at its outlet (i.e. the sediment mixture) and representative soil samples from the four main agricultural fields - expected to be the source soils - of the site were investigated. The bulk delta carbon-13 of the samples and two long-chain FAs (i.e. C22:0 and C24:0) allowed the best statistical discrimination. Using two different mixing models (i.e. IsoSource and CSSIAR v1.00) and the organic carbon content of the soil sources and sediment mixture, the contribution of each source has been established. Results suggested that the grassed waterway contributed to at least 50% of the sediment deposited at the watershed outlet. This study, that will require further validation, highlights that CSSI and Cs-137 techniques are complementary as fingerprints and tracers for establishing land sediment redistribution and could provide meaningful information for optimized decision-making by land managers.

  1. [Responses of Soil and Plant 15N Natural Abundance to Long-term N Addition in an N-Saturated Pinus massoniana Forest in Southwest China].

    PubMed

    Liu, Wen-jing; Kang, Rong-hua; Zhang, Ting; Zhu, Jing; Duan, Lei

    2015-08-01

    Increasing N deposition in China will possibly cause N saturation of forest ecosystem, further resulting in a series of serious environmental problems. In order to explore the response of forest ecosystem to N deposition in China, and further evaluate and predict the N status of ecosystem, the 15N natural abundance (delta 15N) of soil and plants was measured in a typical Masson pine (Pinus massoniana) forest in southwest China to examine the potential use of delta 15N enrichment factor (epsilon(p/s)) as an effective indicator of N status. Long-term high N addition could significantly increase delta 15N of soil and plants, which was suggested by an on-going N fertilizing experiment with NH4NO3 or NaNO3 for 7 years. Meanwhile, delta 15N of soil and plants under NH, deposition was significantly higher than that under NO- deposition, suggesting different responses of ecosystem to different N-forms of deposition. The "N enrichment factor (epsilon(p/s)) had positive correlations with N deposition, N nitrification, and N leaching in the soil water. Linear correlation between "N enrichment factor and N deposition was found for all Masson pine forests investigated in this and previous studies in China, demonstrating that 15N enrichment factor could be used as an indicator of N status. The NH3 emission control should also be carried out accompanying with NOx emission control in the future, because NH4- deposition had significantly greater impact on the forest ecosystem than NO3- deposition with the same equivalence.

  2. Elastin-like polypeptides: biomedical applications of tunable biopolymers.

    PubMed

    MacEwan, Sarah R; Chilkoti, Ashutosh

    2010-01-01

    Artificial repetitive polypeptides have grown in popularity as a bioinspired alternative to synthetic polymers. The genetically encoded synthesis, monodispersity, potential lack of toxicity, and biocompatibility are attractive features of these biopolymers for biological applications. Elastin-like polypeptides (ELPs) are one such class of biopolymers that are of particular interest because of their "smart"-stimuli responsive-properties. Herein, we discuss the genetically encoded design and recombinant synthesis of ELPs that enable precise control of their physicochemical properties and which have led to a wide range of biomedical applications of these biopolymers in the last decade.

  3. Optical properties of DNA-CTMA biopolymers and applications in metal-biopolymer-metal photodetectors

    NASA Astrophysics Data System (ADS)

    Zhou, Bin; Kim, Sung Jin; Bartsch, Carrie M.; Heckman, Emily M.; Ouchen, Fahima; Cartwright, Alexander N.

    2011-09-01

    The potential of using a DNA biopolymer in an electro-optic device is presented. A complex of DNA with the cationic surfactant cetyltrimethylammonium-chloride (CTMA) was used to obtain an organic-soluble DNA material (DNA-CTMA). Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) was added to the DNACTMA to increase the electrical conductivity of the biopolymer. The CW absorbance and time-resolved photoluminescence of the resulting DNA-CTMA and DNA-CTMA-PEDOT:PSS were investigated. Both DNA materials have absorbance peaks at ~260 nm and a broad, Stokes shifted, photoluminescence peak around 470nm. The photoluminescence lifetime of the materials was observed to decrease with increasing UV excitation. Specifically, excitation with a high power ultrafast (~150fs) UV (266nm) laser pulse resulted in a drastic decrease in the photoluminescence lifetime decreases after a few minutes. Moreover, the observed decrease was faster in an air ambient than in a nitrogen ambient. This is most likely due to photo-oxidation that degrades the polymer surface resulting in an increase in the non-radiative recombination. In order to investigate the photoconductivity of these two materials, metal-biopolymer-metal (MBM) ultraviolet photodetectors with interdigitated electrodes were fabricated and characterized. The photoresponsivity of these devices was limited by the transport dynamics within the film. The prospects for the use of these materials in optical devices will be discussed.

  4. Abundance of Ixodes ricinus and prevalence of Borrelia burgdorferi s.l. in the nature reserve Siebengebirge, Germany, in comparison to three former studies from 1978 onwards

    PubMed Central

    2012-01-01

    Background During the last decades, population densities of Ixodes ricinus and prevalences of Borrelia burgdorferi s.l. have increased in different regions in Europe. In the present study, we determined tick abundance and the prevalence of different Borrelia genospecies in ticks from three sites in the Siebengebirge, Germany, which were already examined in the years 1987, 1989, 2001 and 2003. Data from all investigations were compared. Methods In 2007 and 2008, host-seeking I. ricinus were collected by monthly blanket dragging at three distinct vegetation sites in the Siebengebirge, a nature reserve and a well visited local recreation area near Bonn, Germany. In both years, 702 ticks were tested for B. burgdorferi s.l. DNA by nested PCR, and 249 tick samples positive for Borrelia were further genotyped by reverse line blotting. Results A total of 1046 and 1591 I. ricinus were collected in 2007 and 2008, respectively. In comparison to previous studies at these sites, the densities at all sites increased from 1987/89 and/or from 2003 until 2008. Tick densities and Borrelia prevalences in 2007 and 2008, respectively, were not correlated for all sites and both years. Overall, Borrelia prevalence of all ticks decreased significantly from 2007 (19.5%) to 2008 (16.5%), thus reaching the same level as in 2001 two times higher than in 1987/89 (7.6%). Since 2001, single infections with a Borrelia genospecies predominated in all collections, but the number of multiple infections increased, and in 2007, for the first time, triple Borrelia infections occurred. Prevalences of Borrelia genospecies differed considerably between the three sites, but B. garinii or B. afzelii were always the most dominant genospecies. B. lusitaniae was detected for the first time in the Siebengebirge, also in co-infections with B. garinii or B. valaisiana. Conclusions Over the last two centuries tick densities have changed in the Siebengebirge at sites that remained unchanged by human activity since

  5. Biolubricant induced phase inversion and superhydrophobicity in rubber-toughened biopolymer/organoclay nanocomposites

    NASA Astrophysics Data System (ADS)

    Bayer, Ilker S.; Steele, Adam; Martorana, Philip; Loth, Eric; Robinson, Scott J.; Stevenson, Darren

    2009-08-01

    We present a simple technique to fabricate rubber-toughened biopolymer/organoclay nanocomposite coatings with highly water repellent surface wetting characteristics and strong adhesion to metal surfaces. The technique combines the principles of phase inversion and atomization of multicomponent polymer/organoclay suspensions containing a biolubricant as the nonsolvent. The biolubricant was a blend of cyclomethicone/dimethiconol oil with fruit kernel oils. The ternary system of cellulose nitrate/solvent/biolubricant was blended with rubber dispersed organoclay nanofluids. Natural, synthetic, and fluoroacrylic latex rubbers were used for the purpose. Self-cleaning superhydrophobic coatings were obtained from synthetic and fluoroacrylic rubbers whereas natural rubber containing formulations resulted in sticky superhydrophobic coatings.

  6. Clay nanotube-biopolymer composite scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Naumenko, Ekaterina A.; Guryanov, Ivan D.; Yendluri, Raghuvara; Lvov, Yuri M.; Fakhrullin, Rawil F.

    2016-03-01

    Porous biopolymer hydrogels doped at 3-6 wt% with 50 nm diameter/0.8 μm long natural clay nanotubes were produced without any cross-linkers using the freeze-drying method. The enhancement of mechanical strength (doubled pick load), higher water uptake and thermal properties in chitosan-gelatine-agarose hydrogels doped with halloysite was demonstrated. SEM and AFM imaging has shown the even distribution of nanotubes within the scaffolds. We used enhanced dark-field microscopy to visualise the distribution of halloysite nanotubes in the implantation area. In vitro cell adhesion and proliferation on the nanocomposites occur without changes in viability and cytoskeleton formation. In vivo biocompatibility and biodegradability evaluation in rats has confirmed that the scaffolds promote the formation of novel blood vessels around the implantation sites. The scaffolds show excellent resorption within six weeks after implantation in rats. Neo-vascularization observed in newly formed connective tissue placed near the scaffold allows for the complete restoration of blood flow. These phenomena indicate that the halloysite-doped scaffolds are biocompatible as demonstrated both in vitro and in vivo. The chitosan-gelatine-agarose doped clay nanotube nanocomposite scaffolds fabricated in this work are promising candidates for tissue engineering applications.Porous biopolymer hydrogels doped at 3-6 wt% with 50 nm diameter/0.8 μm long natural clay nanotubes were produced without any cross-linkers using the freeze-drying method. The enhancement of mechanical strength (doubled pick load), higher water uptake and thermal properties in chitosan-gelatine-agarose hydrogels doped with halloysite was demonstrated. SEM and AFM imaging has shown the even distribution of nanotubes within the scaffolds. We used enhanced dark-field microscopy to visualise the distribution of halloysite nanotubes in the implantation area. In vitro cell adhesion and proliferation on the nanocomposites occur

  7. Its preferential interactions with biopolymers account for diverse observed effects of trehalose.

    PubMed

    Hong, Jiang; Gierasch, Lila M; Liu, Zhicheng

    2015-07-07

    Biopolymer homeostasis underlies the health of organisms, and protective osmolytes have emerged as one strategy used by Nature to preserve biopolymer homeostasis. However, a great deal remains unknown about the mechanism of action of osmolytes. Trehalose, as a prominent example, stabilizes proteins against denaturation by extreme temperature and denaturants, preserves membrane integrity upon freezing or in dry conditions, inhibits polyQ-mediated protein aggregation, and suppresses the aggregation of denatured proteins. The underlying thermodynamic mechanisms of such diverse effects of trehalose remain unclear or controversial. In this study, we applied the surface-additive method developed in the Record laboratory to attack this issue. We characterized the key features of trehalose-biopolymer preferential interactions and found that trehalose has strong unfavorable interactions with aliphatic carbon and significant favorable interactions with amide/anionic oxygen. This dissection has allowed us to elucidate the diverse effects of trehalose and to identify the crucial functional group(s) responsible for its effects. With (semi)quantitative thermodynamic analysis, we discovered that 1) the unfavorable interaction of trehalose with hydrophobic surfaces is the dominant factor in its effect on protein stability, 2) the favorable interaction of trehalose with polar amides enables it to inhibit polyQ-mediated protein aggregation and the aggregation of denatured protein in general, and 3) the favorable interaction of trehalose with phosphate oxygens, together with its unfavorable interaction with aliphatic carbons, enables trehalose to preserve membrane integrity in aqueous solution. These results provide a basis for a full understanding of the role of trehalose in biopolymer homeostasis and the reason behind its evolutionary selection as an osmolyte, as well as for a better application of trehalose as a chemical chaperone.

  8. End-of-life of starch-polyvinyl alcohol biopolymers.

    PubMed

    Guo, M; Stuckey, D C; Murphy, R J

    2013-01-01

    This study presents a life cycle assessment (LCA) model comparing the waste management options for starch-polyvinyl alcohol (PVOH) biopolymers including landfill, anaerobic digestion (AD), industrial composting and home composting. The ranking of biological treatment routes for starch-PVOH biopolymer wastes depended on their chemical compositions. AD represents the optimum choice for starch-PVOH biopolymer containing N and S elements in global warming potential (GWP(100)), acidification and eutrophication but not on the remaining impact categories, where home composting was shown to be a better option due to its low energy and resource inputs. For those starch-PVOH biopolymers with zero N and S contents home composting delivered the best environmental performance amongst biological treatment routes in most impact categories (except for GWP(100)). The landfill scenario performed generally well due largely to the 100-year time horizon and efficient energy recovery system modeled but this good performance is highly sensitive to assumptions adopted in landfill model.

  9. Adsorption of lead ions on composite biopolymer adsorbent

    SciTech Connect

    Seki, Hideshi; Suzuki, Akira

    1996-04-01

    A fundamental study about the application of biopolymers to the recovery of lead from dilute solution was carried out. A membranous composite biopolymer adsorbent containing two kind of biopolymers, alginic acid (AA) and humic acid (HA), was prepared. HA, which has high solubility in water, was almost completely immobilized in the adsorbent by a combination of calcium alginate gel and activated carbon powder. A general model for complexation between divalent metal ions and acidic sites on biopolymers was applied to explain the adsorption mechanism of lead on the adsorbent (HA-M). The results showed that the complexation constants and the complexation capacities of lead-AA and lead-HA systems were scarcely influenced by immobilization.

  10. Laser-induced periodic surface structuring of biopolymers

    NASA Astrophysics Data System (ADS)

    Pérez, Susana; Rebollar, Esther; Oujja, Mohamed; Martín, Margarita; Castillejo, Marta

    2013-03-01

    We report here on a systematic study about the formation of laser-induced periodic surface structures (LIPSS) on biopolymers. Self-standing films of the biopolymers chitosan, starch and the blend of chitosan with the synthetic polymer poly (vinyl pyrrolidone), PVP, were irradiated in air with linearly polarized laser beams at 193, 213 and 266 nm, with pulse durations in the range of 6-17 ns. The laser-induced periodic surface structures were topographically characterized by atomic force microscopy and the chemical modifications induced by laser irradiation were inspected via Raman spectroscopy. Formation of LIPSS parallel to the laser polarization direction, with periods similar to the laser wavelength, was observed at efficiently absorbed wavelengths in the case of the amorphous biopolymer chitosan and its blend with PVP, while formation of LIPSS is prevented in the crystalline starch biopolymer.

  11. Natural biopolymer for preservation of microorganisms during sampling and storage.

    PubMed

    Sorokulova, Iryna; Watt, James; Olsen, Eric; Globa, Ludmila; Moore, Timothy; Barbaree, James; Vodyanoy, Vitaly

    2012-01-01

    Stability of microbial cultures during sampling and storage is a vital issue in various fields of medicine, biotechnology, food science, and forensics. We have developed a unique bacterial preservation process involving a non-toxic, water-soluble acacia gum polymer that eliminates the need for refrigerated storage of samples. The main goal of this study is to characterize the efficacy of acacia gum polymer for preservation of pathogenic bacteria (Bacillus anthracis and methicillin-resistant Staphylococcus aureus-MRSA) on different materials, used for swabbing and filtration: cotton, wool, polyester, rayon, charcoal cloth, and Whatman paper. Acacia gum polymer used for preservation of two pathogens has been shown to significantly protect bacteria during dehydration and storage in all tested samples at the range of temperatures (5-45°C for MRSA and 40-90°C for B. anthracis). Our results showed higher recovery as well as higher viability during the storage of both bacteria in all materials with acacia gum. Addition of acacia gum polymer to swabbing materials or filters will increase efficacy of sample collection and identification of pathogenic bacteria from locations such as hospitals or the environment. Proposed approach can also be used for long-term storage of culture collections, since acacia gum contributes to viability and stability of bacterial cultures.

  12. Sporopollenin, the least known yet toughest natural biopolymer

    NASA Astrophysics Data System (ADS)

    Mackenzie, Grahame; Boa, Andrew; Taboada, Alberto; Atkin, Stephen; Sathyapalan, Thozhukat

    2015-10-01

    Sporopollenin is highly cross-linked polymer composed of carbon, hydrogen and oxygen that is extraordinarily stable and has been found chemically intact in sedimentary rocks some 500 million year old. It is the outer shell (exine) of plant spores and pollen and when extracted it is in the form of an empty exine or microcapsule. The exines resemble the spores and pollen from which they are extracted, in size and morphology. Also, from any one plant such characteristics are incredible uniform. The exines can be used is microcapsules or simply as micron-sized particles due to the variety of functional groups on their surfaces. The loading of the exine microcapsules into their cavities is via multi-directional nano-diameter sized channels. The exines can be filled with a variety of polar and non-polar materials. Such as enzymes can be encapsulated within the shells and still remain active. In vivo studies in humans have shown that an encapsulated active substance can have a substantially increased bioavailability than if it is taken alone. The sporopollenin exine surface possesses phenolic, alkane, alkene, ketone, lactone and carboxylic acid groups. Therefore it can be derivatised in a number of ways, which has given rise to its having been used for, such as, solid supported for peptide synthesis, catalysis and ion-exchange chromatography. Also, the presence of the phenolic groups on sporopollenin endows it with antioxidant activity.

  13. Role of Native and Exotic Earthworms in Plant Biopolymer Dynamics in Forest Soil

    NASA Astrophysics Data System (ADS)

    Filley, Timothy

    2010-05-01

    Many forests within northern North America are experiencing the introduction of earthworms for the first time, presumably since before the last major glaciation. Forest dynamics are undergoing substantial changes because of the activity of the mainly European lumbricid species. Documented losses in litter layers, expansion of A-horizons, loss of the organic horizon, changes in fine root density, and shifts in microbial populations have all been documented in invaded zones. Two free air CO2 enrichment (FACE) forest experiments (aspen FACE at Rhinelander, Wisconsin and sweet gum FACE at Oak Ridge National Lab, Tennessee) lie within the zones of invasion and exhibit differences in amounts of exotic and native species as well as endogeic (predominantly mineral soil dwelling) and epigeic (litter and organic matter horizon dwelling) types. Considerations of carbon accrual dynamics and relative input of above vs. below ground plant input in these young successional systems do not consider the potential impact of these ecosystem engineers. We investigated the impact of earthworm activity by tracking the relative abundance and stable carbon isotope compositions of lignin and substituted fatty acids extracted from isolated earthworms and their fecal pellets and from host soils. Indications of root vs leaf input to earthworm casts and fecal matter were derived from differences in the chemical composition of cutin, suberin, and lignin. The isotopically depleted CO2 used in FACE and the resulting isotopically depleted plant organic matter afford an excellent opportunity to assess biopolymer-specific turnover dynamics. We find that endogeic species are proportionately more responsible for fine root cycling while some epigeic species are responsible for microaggregation of foliar cutin. CSIA of fecal pellet lignin and SFA indicates how these biopolymer pools can be derived from variable sources, roots, background soil, foliar tissue within one earthworm. Additionally, CSIA

  14. Single Molecule Science for Personalized Nanomedicine: Atomic Force Microscopy of Biopolymer-Protein Interactions

    NASA Astrophysics Data System (ADS)

    Hsueh, Carlin

    Nanotechnology has a unique and relatively untapped utility in the fields of medicine and dentistry at the level of single-biopolymer and -molecule diagnostics. In recent years atomic force microscopy (AFM) has garnered much interest due to its ability to obtain atomic-resolution of molecular structures and probe biophysical behaviors of biopolymers and proteins in a variety of biologically significant environments. The work presented in this thesis focuses on the nanoscale manipulation and observation of biopolymers to develop an innovative technology for personalized medicine while understanding complex biological systems. These studies described here primarily use AFM to observe biopolymer interactions with proteins and its surroundings with unprecedented resolution, providing a better understanding of these systems and interactions at the nanoscale. Transcriptional profiling, the measure of messenger RNA (mRNA) abundance in a single cell, is a powerful technique that detects "behavior" or "symptoms" at the tissue and cellular level. We have sought to develop an alternative approach, using our expertise in AFM and single molecule nanotechnology, to achieve a cost-effective high throughput method for sensitive detection and profiling of subtle changes in transcript abundance. The technique does not require amplification of the mRNA sample because the AFM provides three-dimensional views of molecules with unprecedented resolution, requires minimal sample preparation, and utilizes a simple tagging chemistry on cDNA molecules. AFM images showed collagen polymers in teeth and of Drebrin-A remodeling of filamentous actin structure and mechanics. AFM was used to image collagen on exposed dentine tubules and confirmed tubule occlusion with a desensitizing prophylaxis paste by Colgate-Palmolive. The AFM also superseded other microscopy tools in resolving F-actin helix remodeling and possible cooperative binding by a neuronal actin binding protein---Drebrin-A, an

  15. Reevaluation of siderophile element abundances and ratios across the Cretaceous-Paleogene (K-Pg) boundary: Implications for the nature of the projectile

    NASA Astrophysics Data System (ADS)

    Goderis, S.; Tagle, R.; Belza, J.; Smit, J.; Montanari, A.; Vanhaecke, F.; Erzinger, J.; Claeys, Ph.

    2013-11-01

    The discovery over 30 years ago at Gubbio (Italy) and Caravaca (Spain) of an enrichment in the concentrations of iridium (Ir) and the other platinum group elements (PGE) by up to four orders of magnitude (Irmax = 0.10-87 ng/g) compared to average continental crustal background levels remains one of the most important discoveries in the Earth sciences. Since then, similar anomalies have been detected in more than 120 Cretaceous-Paleogene (K-Pg) boundary sites worldwide. Highly elevated Ir and other siderophile element abundances in roughly chondritic ratios are considered strong indicators for the presence of a meteoritic contribution in impact-related lithologies (melt rocks, impact ejecta material, etc.), delivered when an extraterrestrial object strikes Earth. The presented work adds 113 unpublished PGE analyses of 38 K-Pg sections worldwide to the existing literature. The analytical protocol relied on for this purpose consisted of a combination of a nickel-sulfide fire assay pre-concentration technique and subsequent trace metal determination via inductively coupled plasma-mass spectrometry (ICP-MS). Through repeated determination of key siderophile elements (i.e., Cr, Co, Ni, and PGE), the importance of sampling, nugget effects, and analytical methodologies applied becomes more apparent. Even more critically, these analytical effects are superimposed by the local syn- and post-depositional conditions that have affected the pristine meteoritic signature of the K-Pg impactor, including potential fractionation during vaporization and condensation, dissimilar PGE carrier phases, terrestrial PGE input, sedimentation rate, reworking, diagenesis, bioturbation, and chemical diffusion. While chondrite-normalized PGE patterns of individual sites appear relatively flat (i.e., chondritic), strong variations in siderophile element content and inter-element ratios exist between K-Pg locations, inter-laboratory measurements, and replicate analyses, hampering a precise

  16. Conformational study of C8 diazocine turn mimics using {sup 3}J{sub CH} coupling constants with {sup 13}C in natural abundance

    SciTech Connect

    Bean, J.W.; Briand, J.; Burgess, J.L.; Callahan, J.F.

    1994-12-01

    The conformations of two diazocine turn mimics, which were later incorporated into GPIIb/IIIa peptide antagonists, were investigated using nuclear magnetic resonance techniques. The two compounds, methyl (2,5-dioxo-3-(S)-(3-{omega}-tosylguanidino-propyl)-4-methyl-octahydro-1,4-dazocin-1-yl)acetate (1) and methyl (2,5-dioxo-3-(S)-(3-{omega}-tosyl-guanidino-propyl)-octahydro-1,5-diazocin-1-yl)acetate (2), differ only in their substituent at the diazocine position 4 nitrogen, yet this substitution results in a marked difference in the affinity of the resulting analogs for the GPIIb/IIIa receptor. It was of interest to determine if the difference observed in the antagonistic potency between these analogs was related to constitutional or, perhaps, conformational differences. The backbone conformations of these two molecules can be determined by measuring vicinal coupling constants along the trimethylene portion of the C8 ring backbone and by measuring interproton NOE intensities between the diazocine methine proton and the protons of the trimethylene group. For compound 1, {sup 3}J{sub HH} values measured from a P.E.COSY spectrum and interproton distances calculated from ROESY buildup curves indicated the presence of a single C8 ring backbone conformation where the trimethylene bridge adopted a staggered conformation and the H{alpha}1 and H{gamma}1 protons of the trimethylene group were 2.2 A from the methine proton. For compound 2, however, partial overlap of the central H{beta}1 and H{beta}2 protons made it impossible to measure {sup 3}J{sub HH} values from the P.E.COSY spectrum. We therefore used a {sup 13}C-filtered TOCSY experiment to measure the {sup 3}J{sub CH} values in both compounds 1 and 2. These heteronuclear vicinal coupling constants measured with {sup 13}C in natural abundance in conjunction with measured interproton NOE intensities indicate that these compounds share a common C8 ring backbone conformation.

  17. Importance of structural makeup of biopolymers for organic contaminant sorption.

    PubMed

    Wang, Xilong; Xing, Baoshan

    2007-05-15

    Sorption of pyrene, phenanthrene, naphthalene, and 1-naphthol by original (lignin, chitin, and cellulose) and coated biopolymers was examined. Organic carbon normalized distribution coefficients (Koc) of all compounds by the original biopolymers followed the order lignin > chitin > cellulose, in line with the order of their hydrophobicity. Hydrophobicity of structurally similar organic compounds is the main factor determining their ability to occupy sorption sites in biopolymers. Specific interactions (e.g., H-bonding) between 1-naphthol and chitin or cellulose increased its ability to occupy sorption sites. Lignin coating resulted in an increased Koc for phenanthrene (13.6 times for chitin and 6.9 times for cellulose) and 1-naphthol (6.0 times for chitin and 3.7 times for cellulose) relative to the acetone-treated chitin and cellulose. Also, these coated biopolymers had increased isotherm nonlinearity, due to the newly formed condensed domains. An increase in phenanthrene and 1-naphthol sorption by lignin-coated biopolymers as compared to chitin and cellulose was contributed by the newly created high-energy sites in condensed domains and coated lignin. Results of this study highlight the importance of the structural makeup of biopolymers in controlling the sorption of hydrophobic organic compounds.

  18. Effect of ozone on biopolymers in biofiltration and ultrafiltration processes.

    PubMed

    Siembida-Lösch, Barbara; Anderson, William B; Wang, Yulang Michael; Bonsteel, Jane; Huck, Peter M

    2015-03-01

    The focus of this full-scale study was to determine the effect of ozone on biopolymer concentrations in biofiltration and ultrafiltration (UF) processes treating surface water from Lake Ontario. Ozonation was out of service for maintenance for 9 months, hence, it was possible to investigate ozone's action on biologically active carbon contactors (BACCs) and UF, in terms of biopolymer removal. Given the importance of biopolymers for fouling, this fraction was quantified using a chromatographic technique. Ozone pre-treatment was observed to positively impact the active biomass in biofilters. However, since an increase of the active biomass did not result in higher biopolymer removal, active biomass concentration cannot be a surrogate for biofiltration performance. It was evident that increasing empty bed contact time (EBCT) from 4 to 19 min only had a positive effect on biopolymer removal through BACCs when ozone was out of service. However, as a mass balance experiment showed, ozone-free operation resulted in higher deposition of biopolymers on a UF membrane and slight deterioration in its performance.

  19. Mesoscopic Dynamics of Biopolymers and Protein Molecular Machines

    NASA Astrophysics Data System (ADS)

    Kapral, Raymond

    2013-03-01

    The dynamics of biopolymers in solution and in crowded molecular environments, which mimic some features of the interior of a biochemical cell, will be discussed. In particular, the dynamics of protein machines that utilize chemical energy to effect cyclic conformational changes to carry out their catalytic functions will be described. The investigation of the dynamics of such complex systems requires knowledge of the time evolution on physically relevant long distance and time scales. This often necessitates a coarse grained or mesoscopic treatment of the dynamics. A hybrid particle-based mesoscopic dynamical method, which combines molecular dynamics for a coarse-grain model of the proteins with multiparticle collision dynamics for the solvent, will be described and utilized to study the dynamics of such systems. See, C. Echeverria, Y. Togashi, A. S. Mikhailov, and R. Kapral, Phys. Chem. Chem. Phys 13, 10527 (2011); C. Echeverria and R. Kapral, Phys. Chem. Chem. Phys., 14, 6755 (2012); J. M. Schofield, P. Inder and R. Kapral, J. Chem. Phys. 136, 205101 (2012). Work was supported in part by a grant from the Natural Sciences and Engineering Research Council of Canada.

  20. Characterizing the changes in biopolymer composition in roots of photosynthetically divergent grasses exposed to future climates

    NASA Astrophysics Data System (ADS)

    Suseela, V.; Tharayil, N.; Pendall, E.

    2014-12-01

    A majority of carbon in soil is derived from plant roots, yet roots remain remarkably less explored. Root tissues are abundant in heteropolymers such as suberin, lignin and tannins which are energetically demanding to depolymerize, thus facilitating the accrual of carbon in soil. Most biopolymers are operationally/functionally defined and their function is regulated by the identity of monomers and the linkages connecting these monomers. The structural chemistry of these biopolymers could vary with the environmental conditions experienced during their formative stage thus altering the potential for soil carbon sequestration. We examined the biopolymer composition in the roots of a C3 (Hesperostipa comata) and a C4 (Bouteloua gracilis) grass species exposed to a factorial combination of warming and elevated CO2 at the Prairie Heating and CO2 Enrichment (PHACE) experiment, Wyoming, USA. The grass roots were subjected to a sequential solvent extraction and base hydrolysis to delineate various operational fractions within the polydisperse matrix. The extracted fractions were analyzed using various chromatography mass spectrometry platforms. Warming and elevated CO2 increased the total suberin content and the amount of ω-hydroxy acids in C4 grass species while in C3 species there was a trend of increasing concentration of α,ω-dioic acids in roots exposed to elevated CO2 compared to ambient CO2 treatment. Our results highlight the effect of warming and elevated CO2 on the chemical composition of heteropolymers in roots that may potentially alter root function and rate of decomposition leading to changes in soil carbon in a future warmer world.

  1. Terrestrial plant biopolymers in marine sediments

    NASA Astrophysics Data System (ADS)

    Gough, Mark A.; Fauzi, R.; Mantoura, C.; Preston, Martin

    1993-03-01

    The vascular land plant biopolymers lignin and cutin were surveyed in the surface sediments of coastal and open ocean waters by controlled alkaline CuO oxidation/reaction. Two contrasting oceanic regimes were studied: the northwest Mediterranean (NWM) Sea, which receives significant particulate terrigenous debris through riverine discharge; and the northeast Atlantic (NEA) Ocean, with poorly characterised terrestrial carbon inputs. In the NWM products of lignin and cutin co-occurred at all stations, elevated levels (ca. 0.5-3.0 mg lignin phenols/100 mg organic carbon; ca. 0.01-0.09 mg cutin acids/100 mg organic carbon) were observed for near-shore deltaic and shelf sediments. The influence of terrestrial land plant inputs extended across the shelf and through the slope to the abyssal plain, providing molecular evidence for advective offshore transfer of terrestrial carbon. Mass balance estimates for the basin suggest riverine inputs account for the majority of surface sedimentary lignin/cutin, most of which (>90%) is deposited on the shelf. Products of CuO oxidation of lignin and cutin were also detected in NEA surface sediments, at levels comparable to those observed for the NWM continental slope, and were detectable at low concentrations ( ca. 0.5 μgg-1 in the sediments of the abyssal plains (>4,000 m depth). While atmospheric deposition of lignin/cutin-derived material cannot be discounted in this open ocean system, lateral advective transfer of enriched shelf sediments is inferred as a possible transport process. A progressive enrichment in cutin-derived material relative to lignin was observed offshore, with evidence of an increase in the degree of oxidative alteration of lignin residues. To account for these observations, preferential offshore transport of finer and more degraded material is proposed. Nonspecific oxidation products dominated the gas chromatograms of NEA sediments, which appear to originate from marine sources of sedimentary organic carbon

  2. Formatting and ligating biopolymers using adjustable nanoconfinement

    NASA Astrophysics Data System (ADS)

    Berard, Daniel J.; Shayegan, Marjan; Michaud, Francois; Henkin, Gil; Scott, Shane; Leslie, Sabrina

    2016-07-01

    Sensitive visualization and conformational control of long, delicate biopolymers present critical challenges to emerging biotechnologies and biophysical studies. Next-generation nanofluidic manipulation platforms strive to maintain the structural integrity of genomic DNA prior to analysis but can face challenges in device clogging, molecular breakage, and single-label detection. We address these challenges by integrating the Convex Lens-induced Confinement (CLiC) technique with a suite of nanotopographies embedded within thin-glass nanofluidic chambers. We gently load DNA polymers into open-face nanogrooves in linear, concentric circular, and ring array formats and perform imaging with single-fluorophore sensitivity. We use ring-shaped nanogrooves to access and visualize confinement-enhanced self-ligation of long DNA polymers. We use concentric circular nanogrooves to enable hour-long observations of polymers at constant confinement in a geometry which eliminates the confinement gradient which causes drift and can alter molecular conformations and interactions. Taken together, this work opens doors to myriad biophysical studies and biotechnologies which operate on the nanoscale.

  3. Constitutive modelling of composite biopolymer networks.

    PubMed

    Fallqvist, B; Kroon, M

    2016-04-21

    The mechanical behaviour of biopolymer networks is to a large extent determined at a microstructural level where the characteristics of individual filaments and the interactions between them determine the response at a macroscopic level. Phenomena such as viscoelasticity and strain-hardening followed by strain-softening are observed experimentally in these networks, often due to microstructural changes (such as filament sliding, rupture and cross-link debonding). Further, composite structures can also be formed with vastly different mechanical properties as compared to the individual networks. In this present paper, we present a constitutive model presented in a continuum framework aimed at capturing these effects. Special care is taken to formulate thermodynamically consistent evolution laws for dissipative effects. This model, incorporating possible anisotropic network properties, is based on a strain energy function, split into an isochoric and a volumetric part. Generalisation to three dimensions is performed by numerical integration over the unit sphere. Model predictions indicate that the constitutive model is well able to predict the elastic and viscoelastic response of biological networks, and to an extent also composite structures.

  4. Proton Conductivity Studies on Biopolymer Electrolytes

    SciTech Connect

    Harun, N. I.; Sabri, N. S.; Rosli, N. H. A.; Taib, M. F. M.; Saaid, S. I. Y.; Kudin, T. I. T.; Ali, A. M. M.; Yahya, M. Z. A.

    2010-07-07

    Proton conducting solid biopolymer electrolyte membranes consisting of methyl cellulose (MC) and different wt.% of ammonium nitrate (NH{sub 4}NO{sub 3}) were prepared by solution cast technique. Impedance spectroscopy was carried out to study electrical characteristics of bulk materials. The ionic conductivity of the prepared samples was calculated using the bulk resistance (R{sub b}) obtained from impedance spectroscopy plot. The highest ionic conductivity obtained was 1.17x10{sup -4} Scm{sup -1} for the sample with composition ratio of MC(50): NH{sub 4}NO{sub 3}(50). To enhance the ionic conductivity, propylene carbonate (PC) and ethylene carbonate (EC) plasticizers were introduced. It was found that the ionic conductivity of polymer electrolyte membranes increased with the increase in plasticizers concentration. The ionic conductivities of solid polymer electrolytes based on MC-NH{sub 4}NO{sub 3}-PC was enhanced up to 4.91x10{sup -3} Scm{sup -1} while for the MC-NH{sub 4}NO{sub 3}-EC system, the highest conductivity was 1.74x10{sup -2} Scm{sup -1}. The addition of more plasticizer however decreases in mechanical stability of the membranes.

  5. Customizable Biopolymers for Heavy Metal Remediation

    NASA Astrophysics Data System (ADS)

    Kostal, Jan; Prabhukumar, Giridhar; Lao, U. Loi; Chen, Alin; Matsumoto, Mark; Mulchandani, Ashok; Chen*, Wilfred

    2005-10-01

    Nanoscale materials have been gaining increasing interest in the area of environmental remediation because of their unique physical, chemical and biological properties. One emerging area of research has been the development of novel materials with increased affinity, capacity, and selectivity for heavy metals because conventional technologies are often inadequate to reduce concentrations in wastewater to acceptable regulatory standards. Genetic and protein engineering have emerged as the latest tools for the construction of nanoscale materials that can be controlled precisely at the molecular level. With the advent of recombinant DNA techniques, it is now possible to create `artificial' protein polymers with fundamentally new molecular organization. The most significant feature of these nanoscale biopolymers is that they are specifically pre-programmed within a synthetic gene template and can be controlled precisely in terms of sizes, compositions and functions at the molecular level. In this review, the use of specifically designed protein-based nano-biomaterials with both metal-binding and tunable properties for heavy metal removal is summarized. Several different strategies for the selective removal of heavy metals such as cadmium and mercury are highlighted.

  6. Rotational molding of bio-polymers

    NASA Astrophysics Data System (ADS)

    Greco, Antonio; Maffezzoli, Alfonso; Forleo, Stefania

    2014-05-01

    This paper is aimed to study the suitability of bio-polymers, including poly-lactic acid (PLLA) and Mater-Bi, for the production of hollow components by rotational molding. In order to reduce the brittleness of PLLA, the material was mixed with two different plasticizers, bis-ethyl-hexyl-phthalate (DEHP) and poly-ethylene-glycol (PEG). The materials were characterized in terms of sinterability. To this purpose, thermomechanical (TMA) analysis was performed at different heating rates, in order to identify the endset temperatures of densification and the onset temperatures of degradation. Results obtained indicated that the materials are characterized by a very fast sintering process, occurring just above the melting temperature, and an adequately high onset of degradation. The difference between the onset of degradation and the endset of sintering, defined as the processing window of the polymer, is sufficiently wide, indicating that the polymers can be efficiently processed by rotational molding. Therefore, a laboratory scale apparatus was used for the production of PLLA and Mater-Bi prototypes. The materials were processed using very similar conditions to those used for LLDPE. The production of void-free samples of uniform wall thickness was considered as an indication of the potentiality of the process for the production of biodegradable containers.

  7. A comparative study of biopolymers and alum in the separation and recovery of pulp fibres from paper mill effluent by flocculation.

    PubMed

    Mukherjee, Sumona; Mukhopadhyay, Soumyadeep; Pariatamby, Agamuthu; Ali Hashim, Mohd; Sahu, Jaya Narayan; Sen Gupta, Bhaskar

    2014-09-01

    Recovery of cellulose fibres from paper mill effluent has been studied using common polysaccharides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86mg/L of fibre and was most effective among the biopolymers. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed the highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was the most effective among the biopolymers. Response surface methodology was used to design all experiments, and an optimum operational setting was proposed. The test results indicate similar performance of alum and Guar gum in terms of floc settling velocities and sludge volume index. Since Guar gum is a plant derived natural substance, it is environmentally benign and offers a green treatment option to the paper mills for pulp recycling.

  8. Permeability Modification Using a Reactive Alkaline-Soluble Biopolymer

    SciTech Connect

    Snadra L. Fox; X. Xie; K. D. Schaller; E. P. Robertson; G. A. Bala

    2003-10-01

    Polymer injection has been used in reservoirs to alleviate contrasting permeability zones. Current technology relies on the use of cross-linking agents to initiate gelation. The use of biological polymers are advantageous in that they can block high permeability areas, are environmentally friendly, and have potential to form reversible gels without the use of hazardous cross-linkers. Recent efforts at the Idaho National Engineering and Environmental Laboratory (INEEL) have produced a reactive alkaline-soluble biopolymer from Agrobacterium sp. ATCC no. 31749 that gels upon decreasing the pH of the polymeric solution. The focus of this study was to determine the impact an alkaline-soluble biopolymer can have on sandstone permeability. Permeability modification was investigated by injecting solubilized biopolymer into Berea sandstone cores and defining the contribution of pH, salt, temperature, and Schuricht crude oil on biopolymer gelation. The biopolymer was soluble in KOH at a pH greater than 11.4 and gelled when the pH dropped below 10.8. The Berea sandstone core buffered the biopolymer solution, decreasing the pH sufficiently to form a gel, which subsequently decreased the permeability. The effluent pH of the control cores injected with 0.01 {und M} KOH (pH 12.0) and 0.10{und M} KOH (pH 13.0) decreased to 10.6 and 12.7, respectively. The permeability of the sandstone core injected with biopolymer was decreased to greater than 95% of the original permeability at 25 C in the presence of 2% NaCl, and Schuricht crude oil; however, the permeability increased when the temperature of the core was increased to 60 C. Residual resistance factors as high as 792 were seen in Berea cores treated with biopolymer. The buffering capacity of sandstone has been demonstrated to reduce the pH of a biopolymer solution sufficiently to cause the polymer to form a stable in-situ gel. This finding could potentially lead to alternate technology for permeability modification, thus

  9. Conformon-driven biopolymer shape changes in cell modeling.

    PubMed

    Ji, Sungchul; Ciobanu, Gabriel

    2003-07-01

    Conceptual models of the atom preceded the mathematical model of the hydrogen atom in physics in the second decade of the 20th century. The computer modeling of the living cell in the 21st century may follow a similar course of development. A conceptual model of the cell called the Bhopalator was formulated in the mid-1980s, along with its twin theories known as the conformon theory of molecular machines and the cell language theory of biopolymer interactions [Ann. N.Y. Acad. Sci. 227 (1974) 211; BioSystems 44 (1997) 17; Ann. N.Y. Acad. Sci. 870 (1999a) 411; BioSystems 54 (2000) 107; Semiotica 138 (1-4) (2002a) 15; Fundamenta Informaticae 49 (2002b) 147]. The conformon theory accounts for the reversible actions of individual biopolymers coupled to irreversible chemical reactions, while the cell language theory provides a theoretical framework for understanding the complex networks of dynamic interactions among biopolymers in the cell. These two theories are reviewed and further elaborated for the benefit of both computational biologists and computer scientists who are interested in modeling the living cell and its functions. One of the critical components of the mechanisms of cell communication and cell computing has been postulated to be space- and time-organized teleonomic (i.e. goal-directed) shape changes of biopolymers that are driven by exergonic (free energy-releasing) chemical reactions. The generalized Franck-Condon principle is suggested to be essential in resolving the apparent paradox arising when one attempts to couple endergonic (free energy-requiring) biopolymer shape changes to the exergonic chemical reactions that are catalyzed by biopolymer shape changes themselves. Conformons, defined as sequence-specific mechanical strains of biopolymers first invoked three decades ago to account for energy coupling in mitochondria, have been identified as shape changers, the agents that cause shape changes in biopolymers. Given a set of space- and time

  10. ''Green'' Biopolymers for Improved Decontamination of Metals from Surfaces: Sorptive Characterization and Coating Properties.. Annual report to be submitted to DOE Program Managers for posting on web page.

    SciTech Connect

    Davison, BH

    2001-06-15

    The proposed research aims to develop a fundamental understanding of important biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions. Understanding how heavy metal-chelating biopolymers coat and interact with contaminated surfaces will benefit the development of novel, safe, easy-to-apply decontamination methodologies for removal of radionuclides and heavy metals. The benefits of these methodologies will include the following: decreased exposure hazards for workers; decreased secondary waste generation; increased efficiency of decontamination; positive public appeal and development of novel, nature-friendly business opportunities; and lower cost of cleanup to the government.

  11. Construction of new biopolymer (chitosan)-based pincer-type Pd(II) complex and its catalytic application in Suzuki cross coupling reactions

    NASA Astrophysics Data System (ADS)

    Baran, Talat; Menteş, Ayfer

    2017-04-01

    In this paper we described the fabrication, characterization and application of a new biopolymer (chitosan)-based pincer-type Pd(II) catalyst in Suzuki cross coupling reactions using a non-toxic, cheap, eco-friendly and practical method. The catalytic activity tests showed remarkable product yields as well as TON (19800) and TOF (330000) values with a small catalyst loading. In addition, the catalyst indicated good recyclability in the Suzuki C-C reaction. This biopolymer supported catalyst can be used with various catalyst systems due to its unique properties, such as being inert, green in nature, low cost and chemically durable.

  12. Biopolymer-based thermoplastic mixture for producing solid biodegradable shaped bodies and its photo degradation stability

    NASA Astrophysics Data System (ADS)

    Sulong, Nurulsaidatulsyida; Rus, Anika Zafiah M.

    2013-12-01

    In recent years, biopolymers with controllable lifetimes have become increasingly important for many applications in the areas of agriculture, biomedical implants and drug release, forestry, wild life conservation and waste management. Natural oils are considered to be the most important class of renewable sources. They can be obtained from naturally occurring plants, such as sunflower, cotton, linseed and palm oil. In Malaysia, palm oil is an inexpensive and commodity material. Biopolymer produced from palm oil (Bio-VOP) is a naturally occurring biodegradable polymer and readily available from agriculture. For packaging use however, Bio-VOP is not thermoplastic and its granular form is unsuitable for most uses in the plastics industry, mainly due to processing difficulties during extrusion or injection moulding. Thus, research workers have developed several methods to blend Bio-VOP appropriately for industrial uses. In particular, injections moulding processes, graft copolymerisation, and preparation of blends with thermoplastic polymers have been studied to produce solid biodegradable shaped bodies. HDPE was chosen as commercial thermoplastic materials and was added with 10% Bio-VOP for the preparation of solid biodegradable shaped bodies named as HD-VOP. The UV light exposure of HD-VOP at 12 minutes upon gives the highest strength of this material that is 17.6 MPa. The morphological structure of HD-VOP shows dwi structure surface fracture which is brittle and ductile properties.

  13. Monomers of cutin biopolymer: sorption and esterification on montmorillonite surfaces

    NASA Astrophysics Data System (ADS)

    Olshansky, Yaniv; Polubesova, Tamara; Chefetz, Benny

    2013-04-01

    One of the important precursors for soil organic matter is plant cuticle, a thin layer of predominantly lipids that cover all primary aerial surfaces of vascular plants. In most plant species cutin biopolymer is the major component of the cuticle (30-85% weight). Therefore cutin is the third most abundant plant biopolymer (after lignin and cellulose). Cutin is an insoluble, high molecular weight bio-polyester, which is constructed of inter-esterified cross linked hydroxy-fatty acids and hydroxyepoxy-fatty acids. The most common building blocks of the cutin are derivatives of palmitic acid, among them 9(10),16 dihydroxy palmitic acid (diHPA) is the main component. These fatty acids and their esters are commonly found in major organo-mineral soil fraction-humin. Hence, the complexes of cutin monomers with minerals may serve as model of humin. Both cutin and humin act as adsorption efficient domains for organic contaminants. However, only scarce information is available about the interactions of cutin with soil mineral surfaces, in particular with common soil mineral montmorillonite. The main hypothesize of the study is that adsorbed cutin monomers will be reconstituted on montmorillonite surface due to esterification and oligomerization, and that interactions of cutin monomers with montmorillonite will be affected by the type of exchangeable cation. Cutin monomers were obtained from the fruits of tomato (Lycopersicon esculentum). Adsorption of monomers was measured for crude Wyoming montmorillonites and montmorillonites saturated with Fe3+ and Ca2+. To understand the mechanism of monomer-clay interactions and to evaluate esterification on the clay surface, XRD and FTIR analyses of the montmorillonite-monomers complexes were performed. Our results demonstrated that the interactions of cutin monomers with montmorillonite are affected by the type of exchangeable cation. Isotherms of adsorption of cutin monomers on montmorillonites were fitted by a dual mode model of

  14. Quantitative analysis of biopolymers by matrix-assisted laser desorption

    SciTech Connect

    Tang, K.; Allman, S.L.; Jones, R.B.; Chen, C.H. )

    1993-08-01

    During the past few years, major efforts have been made to use mass spectrometry to measure biopolymers because of the great potential benefit to biological and medical research. Although the theoretical details of laser desorption and ionization mechanisms of MALDI are not yet fully understood, several models have been presented to explain the production of large biopolymer ions. In brief, it is very difficult to obtain reliable measurements of the absolute quantity of analytes by MALDI. If MALDI is going to become a routine analytical tool, it is obvious that quantitative measurement capability must be pursued. Oligonucleotides and protein samples used in this work were purchased from commercial sources. Nicotinic acid was used as matrix for both types of biopolymers. From this experiment, it is seen that it is difficult to obtain absolute quantitative measurements of biopolymers using MALDI. However, internal calibration with molecules having similar chemical properties can be used to resolve these difficulties. Chemical reactions between biopolymers must be avoided to prevent the destruction of the analyte materials. 10 refs., 8 figs.

  15. Imperfection sensitivity of pressured buckling of biopolymer spherical shells

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Ru, C. Q.

    2016-06-01

    Imperfection sensitivity is essential for mechanical behavior of biopolymer shells [such as ultrasound contrast agents (UCAs) and spherical viruses] characterized by high geometric heterogeneity. In this work, an imperfection sensitivity analysis is conducted based on a refined shell model recently developed for spherical biopolymer shells of high structural heterogeneity and thickness nonuniformity. The influence of related parameters (including the ratio of radius to average shell thickness, the ratio of transverse shear modulus to in-plane shear modulus, and the ratio of effective bending thickness to average shell thickness) on imperfection sensitivity is examined for pressured buckling. Our results show that the ratio of effective bending thickness to average shell thickness has a major effect on the imperfection sensitivity, while the effect of the ratio of transverse shear modulus to in-plane shear modulus is usually negligible. For example, with physically realistic parameters for typical imperfect spherical biopolymer shells, the present model predicts that actual maximum external pressure could be reduced to as low as 60% of that of a perfect UCA spherical shell or 55%-65% of that of a perfect spherical virus shell, respectively. The moderate imperfection sensitivity of spherical biopolymer shells with physically realistic imperfection is largely attributed to the fact that biopolymer shells are relatively thicker (defined by smaller radius-to-thickness ratio) and therefore practically realistic imperfection amplitude normalized by thickness is very small as compared to that of classical elastic thin shells which have much larger radius-to-thickness ratio.

  16. Imperfection sensitivity of pressured buckling of biopolymer spherical shells.

    PubMed

    Zhang, Lei; Ru, C Q

    2016-06-01

    Imperfection sensitivity is essential for mechanical behavior of biopolymer shells [such as ultrasound contrast agents (UCAs) and spherical viruses] characterized by high geometric heterogeneity. In this work, an imperfection sensitivity analysis is conducted based on a refined shell model recently developed for spherical biopolymer shells of high structural heterogeneity and thickness nonuniformity. The influence of related parameters (including the ratio of radius to average shell thickness, the ratio of transverse shear modulus to in-plane shear modulus, and the ratio of effective bending thickness to average shell thickness) on imperfection sensitivity is examined for pressured buckling. Our results show that the ratio of effective bending thickness to average shell thickness has a major effect on the imperfection sensitivity, while the effect of the ratio of transverse shear modulus to in-plane shear modulus is usually negligible. For example, with physically realistic parameters for typical imperfect spherical biopolymer shells, the present model predicts that actual maximum external pressure could be reduced to as low as 60% of that of a perfect UCA spherical shell or 55%-65% of that of a perfect spherical virus shell, respectively. The moderate imperfection sensitivity of spherical biopolymer shells with physically realistic imperfection is largely attributed to the fact that biopolymer shells are relatively thicker (defined by smaller radius-to-thickness ratio) and therefore practically realistic imperfection amplitude normalized by thickness is very small as compared to that of classical elastic thin shells which have much larger radius-to-thickness ratio.

  17. Structurally colored biopolymer thin films for detection of dissolved metal ions in aqueous solution

    NASA Astrophysics Data System (ADS)

    Cathell, Matthew David

    Natural polymers, such as the polysaccharides alginate and chitosan, are noted sorbents of heavy metals. Their polymer backbone structures are rich in ligands that can interact with metal ions through chelation, electrostatics, ion exchange and nonspecific mechanisms. These water-soluble biopolymer materials can be processed into hydrogel thin films, creating high surface area interfaces ideal for binding and sequestering metal ions from solution. By virtue of their uniform nanoscale dimensions (with thicknesses smaller than wavelengths of visible light) polymer thin films exhibit structure-based coloration. This phenomenon, frequently observed in nature, causes the transparent and essentially colorless films to reflect light in a wide array of colors. The lamellar film structures act as one-dimensional photonic crystals, allowing selective reflection of certain wavelengths of light while minimizing other wavelengths by out-of-phase interference. The combination of metal-binding and reflective properties make alginate and chitosan thin films attractive candidates for analyte sensing. Interactions with metal ions can induce changes in film thicknesses and refractive indices, thus altering the path of light reflected through the film. Small changes in dimensional or optical properties can lead to shifts in film color that are perceivable by the unaided eye. These thin films offer the potential for optical sensing of toxic dissolved materials without the need for instrumentation, external power or scientific expertise. With the use of a spectroscopic ellipsometer and a fiber optic reflectance spectrometer, the physical and optical characteristics of biopolymer thin films have been characterized in response to 50 ppm metal ion solutions. It has been determined that metal interactions can lead to measurable changes in both film thicknesses and effective refractive indices. The intrinsic response behaviors of alginate and chitosan, as well as the responses of modified

  18. Estimates of N2 Fixation Based on Differences in the Natural Abundance of 15N in Nodulating and Nonnodulating Isolines of Soybeans 1

    PubMed Central

    Kohl, Daniel H.; Shearer, Georgia; Harper, James E.

    1980-01-01

    Estimates of the contribution of biologically fixed N to the total N of nodulating soybeans (Glycine max (L) Merrill, variety Harosoy) grown under a variety of conditions were made from: (a) differences in N yield between nodulating and nonnodulating isolines; and (b) differences in 15N abundance between the two isolines. For plants grown in a greenhouse in nutrient-poor soil, both estimates showed a high level of N2 fixation; from 58 to 89% N fixed by differences in N yield and from 51 to 95% by differences in 15N abundance. Decreasing contributions of fixed N were estimated by both methods with increasing levels of added NO3−. Results of field experiments carried out over two years on an unamended highly fertile midwestern soil showed a modest level of N2 fixation by both methods (7.3 to 51% by differences in N yield, and 5.4 to 46% by differences in 15N abundance). When the soil was amended with ground corn cobs, both methods showed higher contributions of fixed N. The two methods of estimating N2 fixation gave similar results. Both appear to be semiquantitative and the standard errors of the estimates were about the same (6% on the average). PMID:16661394

  19. Surface enhaced raman scattering (SERS) with biopolymer encapsulated silver nanosubstrates for rapid detection of foodborne pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A biopolymer encapsulated with silver nanoparticles was prepared using polyvinyl alcohol (PVA) solution, silver nitrate, and trisodium citrate. Biopolymer based nanosubstrates were deposited on a mica sheet for SERS. Fresh cultures of Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus a...

  20. Synthetic and Biopolymer Gels - Similarities and Difference.

    NASA Astrophysics Data System (ADS)

    Horkay, Ferenc

    2006-03-01

    Ion exchange plays a central role in a variety of physiological processes, such as nerve excitation, muscle contraction and cell locomotion. Hydrogels can be used as model systems for identifying fundamental chemical and physical interactions that govern structure formation, phase transition, etc. in biopolymer systems. Polyelectrolyte gels are particularly well-suited to study ion-polymer interactions because their structure and physical-chemical properties (charge density, crosslink density, etc) can be carefully controlled. They are sensitive to different external stimuli such as temperature, ionic composition and pH. Surprisingly few investigations have been made on polyelectrolyte gels in salt solutions containing both monovalent and multivalent cations. We have developed an experimental approach that combines small angle neutron scattering and osmotic swelling pressure measurements. The osmotic pressure exerted on a macroscopic scale is a consequence of changes occurring at a molecular level. The intensity of the neutron scattering signal, which provides structural information as a function of spatial resolution, is directly related to the osmotic pressure. We have found a striking similarity in the scattering and osmotic behavior of polyacrylic acid gels and DNA gels swollen in nearly physiological salt solutions. Addition of calcium ions to both systems causes a sudden volume change. This volume transition, which occurs when the majority of the sodium counterions are replaced by calcium ions, is reversible. Such reversibility implies that the calcium ions are not strongly bound by the polyanion, but are free to move along the polymer chain, which allows these ions to form temporary bridges between negative charges on adjacent chains. Mechanical measurements reveal that the elastic modulus is practically unchanged in the calcium-containing gels, i.e., ion bridging is qualitatively different from covalent crosslinks.

  1. Biopolymers for sample collection, protection, and preservation.

    PubMed

    Sorokulova, Iryna; Olsen, Eric; Vodyanoy, Vitaly

    2015-07-01

    One of the principal challenges in the collection of biological samples from air, water, and soil matrices is that the target agents are not stable enough to be transferred from the collection point to the laboratory of choice without experiencing significant degradation and loss of viability. At present, there is no method to transport biological samples over considerable distances safely, efficiently, and cost-effectively without the use of ice or refrigeration. Current techniques of protection and preservation of biological materials have serious drawbacks. Many known techniques of preservation cause structural damages, so that biological materials lose their structural integrity and viability. We review applications of a novel bacterial preservation process, which is nontoxic and water soluble and allows for the storage of samples without refrigeration. The method is capable of protecting the biological sample from the effects of environment for extended periods of time and then allows for the easy release of these collected biological materials from the protective medium without structural or DNA damage. Strategies for sample collection, preservation, and shipment of bacterial, viral samples are described. The water-soluble polymer is used to immobilize the biological material by replacing the water molecules within the sample with molecules of the biopolymer. The cured polymer results in a solid protective film that is stable to many organic solvents, but quickly removed by the application of the water-based solution. The process of immobilization does not require the use of any additives, accelerators, or plastifiers and does not involve high temperature or radiation to promote polymerization.

  2. Optically controlled multiple switching operations of DNA biopolymer devices

    SciTech Connect

    Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu; Fruk, Ljiljana; Hung, Yu-Chueh

    2015-12-21

    We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices.

  3. Conducting and non-conducting biopolymer composites produced by particle bonding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this report, we introduce two types of processes for the production of biopolymer composites: one is fabricated by bonding biopolymers with corn protein or wheat protein and the other by bonding starch with a synthetic polymer. These two types of biopolymer composites make use of the strong bon...

  4. Nonlinearities of biopolymer gels increase the range of force transmission.

    PubMed

    Xu, Xinpeng; Safran, Samuel A

    2015-09-01

    We present a model of biopolymer gels that includes two types of elastic nonlinearities, stiffening under extension and softening (due to buckling) under compression, to predict the elastic anisotropy induced by both external as well as internal (e.g., due to cell contractility) stresses in biopolymer gels. We show how the stretch-induced anisotropy and the strain-stiffening nonlinearity increase both the amplitude and power-law range of transmission of internal, contractile, cellular forces, and relate this to recent experiments.

  5. Models of the solvent-accessible surface of biopolymers

    SciTech Connect

    Smith, R.E.

    1996-09-01

    Many biopolymers such as proteins, DNA, and RNA have been studied because they have important biomedical roles and may be good targets for therapeutic action in treating diseases. This report describes how plastic models of the solvent-accessible surface of biopolymers were made. Computer files containing sets of triangles were calculated, then used on a stereolithography machine to make the models. Small (2 in.) models were made to test whether the computer calculations were done correctly. Also, files of the type (.stl) required by any ISO 9001 rapid prototyping machine were written onto a CD-ROM for distribution to American companies.

  6. Length regulation of active biopolymers by molecular motors.

    PubMed

    Johann, Denis; Erlenkämper, Christoph; Kruse, Karsten

    2012-06-22

    For biopolymers like cytoskeletal actin filaments and microtubules, assembly and disassembly are inherently dissipative processes. Molecular motors can affect the rates of subunit removal at filament ends. We introduce a driven lattice-gas model to study the effects of motor-induced depolymerization on the length of active biopolymers and find that increasing motor activity sharpens unimodal steady-state length distributions. Furthermore, for sufficiently fast moving motors, the relative width of the length distribution is determined only by the attachment rate of motors. Our results show how established molecular processes can be used to robustly regulate the size of cytoskeletal structures like mitotic spindles.

  7. Distribution and abundance of natural parasitoid (Hymenoptera: Pteromalidae) populations of house flies and stable flies (Diptera: Muscidae) at the University of Florida Dairy Research Unit.

    PubMed

    Romero, Alvaro; Hogsette, Jerome A; Coronado, Alfredo

    2010-01-01

    From September 2001 through September 2002, house fly and stable fly pupae were collected weekly from three fly habitats at the University of Florida Research dairy in northcentral Florida and evaluated for parasitism. Varying parasitism percentages were observed throughout the study but they were not affected by temperature, precipitation or fly abundance. Of the 6,222 house fly pupae and 1,660 stable fly pupae that produced either a host fly or a parasitoid, 26.9% and 26.7% were parasitized, respectively. Ten parasitoid species were recovered, with the genus Spalangia accounting for 85.7% of the total; the most common parasitoids attacking house fly and stable fly pupae were Spalangia endius Walker (33.9% and 27.3%), S. cameroni Perkins (27.9% and 40.6%), and S. nigroaenea Curtis (21.0% and 24.8%), respectively. Other parasitoids included one specimen of S. erythromera Förster and four specimens of Phygadeuon fumator Gravenhörst (Ichneumonidae). The percentage parasitism of pupae collected from bunker silos was higher than that of pupae from calf pens and open pastures. Spalangia cameroni was consistently recovered through the entire year. Spalangia nigroaenea was predominant in July, August, and September. Spalangia endius was most active from October to May with a peak of relative abundance in January.

  8. SIR2 and other genes are abundantly expressed in long-lived natural segregants for replicative aging of the budding yeast Saccharomyces cerevisiae.

    PubMed

    Guo, Zhenhua; Adomas, Aleksandra B; Jackson, Erin D; Qin, Hong; Townsend, Jeffrey P

    2011-06-01

    We investigated the mechanism underlying the natural variation in longevity within natural populations using the model budding yeast, Saccharomyces cerevisiae. We analyzed whole-genome gene expression in four progeny of a natural S. cerevisiae strain that display differential replicative aging. Genes with different expression levels in short- and long-lived strains were classified disproportionately into metabolism, transport, development, transcription or cell cycle, and organelle organization (mitochondrial, chromosomal, and cytoskeletal). With several independent validating experiments, we detected 15 genes with consistent differential expression levels between the long- and the short-lived progeny. Among those 15, SIR2, HSP30, and TIM17 were upregulated in long-lived strains, which is consistent with the known effects of gene silencing, stress response, and mitochondrial function on aging. The link between SIR2 and yeast natural life span variation offers some intriguing ties to the allelic association of the human homolog SIRT1 to visceral obesity and metabolic response to lifestyle intervention.

  9. Particle designs for the stabilization and controlled-delivery of protein drugs by biopolymers: a case study on insulin.

    PubMed

    Lim, Hui-Peng; Tey, Beng-Ti; Chan, Eng-Seng

    2014-07-28

    Natural biopolymers have attracted considerable interest for the development of delivery systems for protein drugs owing to their biocompatibility, non-toxicity, renewability and mild processing conditions. This paper offers an overview of the current status and future perspectives of particle designs using biopolymers for the stabilization and controlled-delivery of a model protein drug--insulin. We first describe the design criteria for polymeric encapsulation and subsequently classify the basic principles of particle fabrication as well as the existing particle designs for oral insulin encapsulation. The performances of these existing particle designs in terms of insulin stability and in vitro release behavior in acidic and alkaline media, as well as their in vivo performance are compared and reviewed. This review forms the basis for future works on the optimization of particle design and material formulation for the development of an improved oral delivery system for protein drugs.

  10. Sugar Based Biopolymers in Nanomedicine; New Emerging Era for Cancer Imaging and Therapy.

    PubMed

    Eroglu, Mehmet S; Oner, Ebru Toksoy; Mutlu, Esra Cansever; Bostan, Muge Sennaroglu

    2016-12-21

    Since last decade, sugar based biopolymers are recognized in nanomedicine as promising materials for cancer imaging and therapy. Their durable, biocompatible and adhesive properties enable the fine tuning of their molecular weights (MW) and their miscellaneous nature makes the molecules acquire various conformations. These in turn provide effective endocytosis by cancer cell membranes that have already been programmed for internalization of different kinds of sugars. Therefore, biocompatible sugar based nanoparticles (SBNPs) are suitable for both cell-selective delivery of drugs and imaging through the human body. Recently, well known sugar-based markers have displayed superior performance to overcome tumor metastasis. Thereby, targeting strategies for cancer cells have been broadened to sugar-based markers as noticed in various clinic phases. In these studies, biopolymers such as chitosan, hyaluronic acid, mannan, dextran, levan, pectin, cyclodextrin, chondroitin sulphate, alginates, amylose and heparin are chemically functionalized and structurally designed as new biocompatible nanoparticles (NPs). The future cancer treatment strategies will mainly comprise of these multifunctional sugar based nanoparticles which combine the therapeutic agents with imaging technologies with the aim of rapid monitoring response to therapies. While each individual imaging and treatment step requires a long time period in effective treatment of diseases, these multifunctional sugar based nanoparticles will have the advantage of rapid detection, right drug efficiency evaluation and immediate interfere opportunity to some important diseases, especially rapidly progressing cancers. In this article, we evaluated synthesis, characterization and applications of main sugar based biopolymers and discussed their great promise in nano-formulations for cancer imaging and therapy. However much should be done and optimized prior to clinical applications of these nano-formulations for an

  11. Aliphatic and aromatic plant biopolymer dynamics in soil particles isolated from sequential density fractionation

    NASA Astrophysics Data System (ADS)

    Caldwell, B.; Filley, T.; Sollins, P.; Lajtha, K.; Swanston, C.; Kleber, M.; Kramer, M.

    2007-12-01

    A recent multi-layer-based soil organic matter-mineral interaction mechanistic model to describe the nature of soil organic matter-mineral surface mechanism for soil organic matter stabilization predicts that proteinaceous and aliphatic materials establish the core of strong binding-interactions upon which other organic matter is layered. A key methodology providing data underpinning this hypothesis is sequential density fractionation where soil is partitioned into particles of increasing density with the assumption that a partial control on organic matter distribution through density series is the thickness of its layering. Four soils of varying mineralogy and texture were investigated for their biopolymer, isotopic, and mineralogical properties. Light fractions (<1.8 g/cm3), although dominanted by organic detritus, did not always contain the highest concentration of lignin and substituted fatty acids from cutin and suberin while heavier fractions, 1.8-2.6 g/cm3, exhibited a progressive decrease in concentration in plant derived biopolymers with density. Extractable lignin phenols exhibited a progressive oxidation state with density. The concentration of biopolymers roughly mirrored the C:N ratio of soil particles which dropped consistently with increasing particle density. Although, in all soils, both lignin phenols and SFA concentration generally decreased with increasing density the ratio SFA/lignin varied with density and depending upon the soil. All soils, except the oxisol, exhibited an increase in SFA with respect to lignin suggesting a selective stabilization of those material with respect to lignin. In the oxisol, which showed little variation in its hematite dominated mineralogy across density, SFA/lignin remained constant, potentially indicating a greater capacity to stabilize lignin in that system. Interestingly, the lignin oxidation state increased with density in the oxisol. Given the variation in soil character, the consistency in these trends it

  12. Abundance, Natural Infection with Trypanosomes, and Food Source of an Endemic Species of Triatomine, Panstrongylus howardi (Neiva 1911), on the Ecuadorian Central Coast

    PubMed Central

    Villacís, Anita G.; Ocaña-Mayorga, Sofía; Lascano, Mauricio S.; Yumiseva, César A.; Baus, Esteban G.; Grijalva, Mario J.

    2015-01-01

    The elimination of domestic triatomines is the foundation of Chagas disease control. Regional initiatives are eliminating introduced triatomine species. In this scenario, endemic triatomines can occupy the ecological niches left open and become a threat to long-term Chagas disease control efforts. This study determined the abundance, colonization, and Trypanosoma cruzi infection rate of the endemic Panstrongylus howardi in 10 rural communities located in Ecuador's Manabí Province. In total, 518 individuals of P. howardi were collected. Infestation indices of 1.4% and 6.6% were found in the domestic and peridomestic environments, respectively. We determined a T. cruzi infection rate of 53.2% (N = 47) in this species. P. howardi has a high capacity to adapt to different habitats, especially in the peridomicile. This implies a considerable risk of transmission because of the frequency of intradomicile invasion. Therefore, this species needs to be taken into account in Chagas control and surveillance efforts in the region. PMID:25385867

  13. Abundance, natural infection with trypanosomes, and food source of an endemic species of triatomine, Panstrongylus howardi (Neiva 1911), on the Ecuadorian Central Coast.

    PubMed

    Villacís, Anita G; Ocaña-Mayorga, Sofía; Lascano, Mauricio S; Yumiseva, César A; Baus, Esteban G; Grijalva, Mario J

    2015-01-01

    The elimination of domestic triatomines is the foundation of Chagas disease control. Regional initiatives are eliminating introduced triatomine species. In this scenario, endemic triatomines can occupy the ecological niches left open and become a threat to long-term Chagas disease control efforts. This study determined the abundance, colonization, and Trypanosoma cruzi infection rate of the endemic Panstrongylus howardi in 10 rural communities located in Ecuador's Manabí Province. In total, 518 individuals of P. howardi were collected. Infestation indices of 1.4% and 6.6% were found in the domestic and peridomestic environments, respectively. We determined a T. cruzi infection rate of 53.2% (N = 47) in this species. P. howardi has a high capacity to adapt to different habitats, especially in the peridomicile. This implies a considerable risk of transmission because of the frequency of intradomicile invasion. Therefore, this species needs to be taken into account in Chagas control and surveillance efforts in the region.

  14. Production of a Biopolymer at Reactor Scale: A Laboratory Experience

    ERIC Educational Resources Information Center

    Genc, Rukan; Rodriguez-Couto, Susana

    2011-01-01

    Undergraduate students of biotechnology became familiar with several aspects of bioreactor operation via the production of xanthan gum, an industrially relevant biopolymer, by "Xanthomonas campestris" bacteria. The xanthan gum was extracted from the fermentation broth and the yield coefficient and productivity were calculated. (Contains 2 figures.)

  15. Production of Degradable Biopolymer Composites by Particle-bonding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventionally, polymer composites had been manufactured by mixing the component materials in the extruder at high temperature. Agricultural biopolymers are usually mixtures of many types of compounds; when used as raw materials, however, high-temperature process causes unwanted consequences such a...

  16. Biopolymers in controlled release devices for agricultural applications.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of biopolymers such as starch for agricultural applications including controlled release devices is growing due the environmental benefits. Recently, concerns have grown about the worldwide spread of parasitic mites (Varroa destructor) that infect colonies of honey bees (Apis mellifera L.). ...

  17. USING BIOPOLYMERS TO REMOVE HEAVY METALS FROM SOIL AND WATER

    EPA Science Inventory

    Chemical remediation of soil may involve the use of harsh chemicals that generate waste streams, which may adversely affect the soil's integrity and ability to support vegetation. This article reviews the potential use of benign reagents, such as biopolymers, to extract heavy me...

  18. Biopolymers produced from gelatin and other sustainable resources using polyphenols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several researchers have recently demonstrated the feasibility of producing biopolymers from the reaction of polyphenolics with gelatin in combination with other proteins (e.g. whey) or with carbohydrates (e.g. chitosan and pectin). These combinations would take advantage of the unique properties o...

  19. Polymer and biopolymer mediated self-assembly of gold nanoparticles.

    PubMed

    Ofir, Yuval; Samanta, Bappaditya; Rotello, Vincent M

    2008-09-01

    Gold nanoparticle-polymer composites are versatile and diverse functional materials, with applications in optical, electronic and sensing devices. This tutorial review focuses on the use of polymers to control the assembly of gold nanoparticles. Examples of synthetic polymers and biopolymers are provided, as well as applications of the composite materials in sensing and memory devices.

  20. Development of correlations to predict biopolymer mobility in porous media

    SciTech Connect

    Hejri, S.; Willhite, G.P.; Green, D.W. )

    1991-02-01

    This paper describes the flow and rheological behavior of biopolymer solutions in sandpacks over a wide range of permeability and frontal advance rates. Empirical correlations were developed to estimate polymer mobility in porous media. The correlations are based on porous medium properties, polymer concentration, and rheological parameters for the polymer derived from steady-shear measurements.

  1. Latent Oxidative Polymerization of Catecholamines as Potential Cross-linkers for Biocompatible and Multifunctional Biopolymer Scaffolds.

    PubMed

    Dhand, Chetna; Barathi, Veluchamy Amutha; Ong, Seow Theng; Venkatesh, Mayandi; Harini, Sriram; Dwivedi, Neeraj; Goh, Eunice Tze Leng; Nandhakumar, Muruganantham; Venugopal, Jayarama Reddy; Diaz, Silvia Marrero; Fazil, Mobashar Hussain Urf Turabe; Loh, Xian Jun; Ping, Liu Shou; Beuerman, Roger W; Verma, Navin Kumar; Ramakrishna, Seeram; Lakshminarayanan, Rajamani

    2016-11-30

    Electrospinning of naturally occurring biopolymers for biological applications requires postspinning cross-linking for endurance in protease-rich microenvironments and prevention of rapid dissolution. The most commonly used cross-linkers often generate cytotoxic byproducts, which necessitate high concentrations or time-consuming procedures. Herein, we report the addition of "safe" catecholamine cross-linkers to collagen or gelatin dope solutions followed by electrospinning yielded junction-containing nanofibrous mats. Subsequent in situ oxidative polymerization of the catecholamines increased the density of soldered junctions and maintained the porous nanofiber architecture. This protocol imparted photoluminescence to the biopolymers, a smooth noncytotoxic coating, and good mechanical/structural stability in aqueous solutions. The utility of our approach was demonstrated by the preparation of durable antimicrobial wound dressings and mineralized osteoconductive scaffolds via peptide antibiotics and calcium chloride (CaCl2) incorporation into the dope solutions. The mineralized composite mats consist of amorphous calcium carbonate that enhanced the osteoblasts cell proliferation, differentiation, and expression of important osteogenic marker proteins. In proof-of-concept experiments, antibiotic-loaded mats displayed superior antimicrobial properties relative to silver (Ag)-based dressings, and accelerated wound healing in a porcine deep dermal burn injury model.

  2. The stability and degradation kinetics of Sulforaphene in microcapsules based on several biopolymers via spray drying.

    PubMed

    Tian, Guifang; Li, Yuan; Yuan, Qipeng; Cheng, Li; Kuang, Pengqun; Tang, Pingwah

    2015-05-20

    Sulforaphene (SFE) was extracted from the radish seeds and the purity of SFE extracted by our laboratory was 95%. It is well known that SFE can prevent cancers. It is also known that SFE is unstable to heat. To overcome the problem, SFE microcapsules using natural biopolymers were prepared by spray drying. The results indicated that SFE microcapsules using hydroxypropyl-β-cyclodextrin (HP-β-CD), maltodextrin (MD) and isolated soybean protein (SPI) as wall materials could effectively improve its stability against heat, especially SFE-loaded HP-β-CD and MD microcapsules. The amount of SFE in the microcapsules was found 20% higher than that of the non-encapsulated SFE under 90 °C in 168 h. Our finding suggested that the rate of degradation of the non-encapsulated and encapsulated SFE with HP-β-CD, MD and SPI followed the first-order kinetics. The speed of the degradation of the encapsulated SFE in biopolymers increased from SFE with HP-β-CD, to SFE with MD, and to SFE-SPI. The non-encapsulated SFE degrades fastest.

  3. Active biopolymers in green non-conventional media: a sustainable tool for developing clean chemical processes.

    PubMed

    Lozano, Pedro; Bernal, Juana M; Nieto, Susana; Gomez, Celia; Garcia-Verdugo, Eduardo; Luis, Santiago V

    2015-12-21

    The greenness of chemical processes turns around two main axes: the selectivity of catalytic transformations, and the separation of pure products. The transfer of the exquisite catalytic efficiency shown by enzymes in nature to chemical processes is an important challenge. By using appropriate reaction systems, the combination of biopolymers with supercritical carbon dioxide (scCO2) and ionic liquids (ILs) resulted in synergetic and outstanding platforms for developing (multi)catalytic green chemical processes, even under flow conditions. The stabilization of biocatalysts, together with the design of straightforward approaches for separation of pure products including the full recovery and reuse of enzymes/ILs systems, are essential elements for developing clean chemical processes. By understanding structure-function relationships of biopolymers in ILs, as well as for ILs themselves (e.g. sponge-like ionic liquids, SLILs; supported ionic liquids-like phases, SILLPs, etc.), several integral green chemical processes of (bio)catalytic transformation and pure product separation are pointed out (e.g. the biocatalytic production of biodiesel in SLILs, etc.). Other developments based on DNA/ILs systems, as pathfinder studies for further technological applications in the near future, are also considered.

  4. A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess

    DOE PAGES

    Zhang, Junsong; Cui, Lishan; Jiang, Daqiang; ...

    2015-02-10

    The design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature’s armor, is renowned for its unusual combination of strength and toughness. Nature’s wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer’s deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memory alloy to transcribemore » the ‘‘J-curve’’ mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti₃Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials.« less

  5. A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess

    SciTech Connect

    Zhang, Junsong; Cui, Lishan; Jiang, Daqiang; Liu, Yinong; Hao, Shijie; Ren, Yang; Han, Xiaodong; Liu, Zhenyang; Wang, Yunzhi; Yu, Cun; Huan, Yong; Zhao, Xinqing; Zheng, Yanjun; Xu, Huibin; Ren, Xiaobing; Li, Xiaodong

    2015-02-10

    The design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature’s armor, is renowned for its unusual combination of strength and toughness. Nature’s wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer’s deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memory alloy to transcribe the ‘‘J-curve’’ mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti₃Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials.

  6. Design of biomimetic super-lubricants by hydrogel-biopolymer aggregates

    NASA Astrophysics Data System (ADS)

    Seekell, Raymond; Dever, Rachel; Zhu, Yingxi

    2013-03-01

    Inspired by the superb lubricity of natural synovial fluids for moving articular cartilage joints, we investigate a biomimetic artificial lubricant based on a hydrogel-biopolymer mixture with optimized rheological properties at a microscopic level. Specifically, we examine the structure and rheological relationship of stimuli-responsive poly (N-isopropylacrylamide) (PNIPAM) hydrogel added with hyaluronic acid (HA) to simulate the complexes of HA with a globule protein, lubricin, which are credited as the two key lubricious constituents in natural synovial fluids. By combined microscopic structural characterization and rheology measurement, we tune the rheological and frictional behaviors of HA solutions by optimizing the content of added micron-sized PNIPAM hydrogel particles to form stable PNIPAM-HA network. In a recent work on using zwitterionic hydrogel particles instead of negatively charged PNIPAM, comparable structure and rheological properties of hydrogel-HA aggregates are observed, which may give insight to design new biocompatible lubricants and lubricious coatings for medical ramification.

  7. Strong anion exchange liquid chromatographic separation of protein amino acids for natural 13C-abundance determination by isotope ratio mass spectrometry.

    PubMed

    Abaye, Daniel A; Morrison, Douglas J; Preston, Tom

    2011-02-15

    Amino acids are the building blocks of proteins and the analysis of their (13)C abundances is greatly simplified by the use of liquid chromatography (LC) systems coupled with isotope ratio mass spectrometry (IRMS) compared with gas chromatography (GC)-based methods. To date, various cation exchange chromatography columns have been employed for amino acid separation. Here, we report strong anion exchange chromatography (SAX) coupled to IRMS with a Liquiface interface for amino acid δ(13)C determination. Mixtures of underivatised amino acids (0.1-0.5 mM) and hydrolysates of representative proteins (prawns and bovine serum albumin) were resolved by LC/IRMS using a SAX column and inorganic eluents. Background inorganic carbon content was minimised through careful preparation of alkaline reagents and use of a pre-injector on-line carbonate removal device. SAX chromatography completely resolved 11 of the 16 expected protein amino acids following acid hydrolysis in underivatised form. Basic and neutral amino acids were resolved with 35 mM NaOH in isocratic mode. Elution of the aromatic and acidic amino acids required a higher hydroxide concentration (180 mM) and a counterion (NO 3-, 5-25 mM). The total run time was 70 min. The average δ(13)C precision of baseline-resolved peaks was 0.75‰ (range 0.04 to 1.06‰). SAX is a viable alternative to cation chromatography, especially where analysis of basic amino acids is important. The technology shows promise for (13)C amino acid analysis in ecology, archaeology, forensic science, nutrition and protein metabolism.

  8. Film forming microbial biopolymers for commercial applications--a review.

    PubMed

    Vijayendra, S V N; Shamala, T R

    2014-12-01

    Microorganisms synthesize intracellular, structural and extracellular polymers also referred to as biopolymers for their function and survival. These biopolymers play specific roles as energy reserve materials, protective agents, aid in cell functioning, the establishment of symbiosis, osmotic adaptation and support the microbial genera to function, adapt, multiply and survive efficiently under changing environmental conditions. Viscosifying, gelling and film forming properties of these have been exploited for specific significant applications in food and allied industries. Intensive research activities and recent achievements in relevant and important research fields of global interest regarding film forming microbial biopolymers is the subject of this review. Microbial polymers such as pullulan, kefiran, bacterial cellulose (BC), gellan and levan are placed under the category of exopolysaccharides (EPS) and have several other functional properties including film formation, which can be used for various applications in food and allied industries. In addition to EPS, innumerable bacterial genera are found to synthesis carbon energy reserves in their cells known as polyhydroxyalkanoates (PHAs), microbial polyesters, which can be extruded into films with excellent moisture and oxygen barrier properties. Blow moldable biopolymers like PHA along with polylactic acid (PLA) synthesized chemically in vitro using lactic acid (LA), which is produced by LA bacteria through fermentation, are projected as biodegradable polymers of the future for packaging applications. Designing and creating of new property based on requirements through controlled synthesis can lead to improvement in properties of existing polysaccharides and create novel biopolymers of great commercial interest and value for wider applications. Incorporation of antimicrobials such as bacteriocins or silver and copper nanoparticles can enhance the functionality of polymer films especially in food packaging

  9. Engineered biosealant producing inorganic and organic biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbiologically induced calcium carbonate precipitation (MICCP) is a naturally occurring biological process that has shown its potential in remediation of a wide range of structural damages including concrete cracks. MICCP involves sequential microbiological and chemical reactions, such as urea h...

  10. Robust Abundance Estimation in Animal Abundance Surveys with Imperfect Detection

    EPA Science Inventory

    Surveys of animal abundance are central to the conservation and management of living natural resources. However, detection uncertainty complicates the sampling process of many species. One sampling method employed to deal with this problem is depletion (or removal) surveys in whi...

  11. Identification of microbial populations driving biopolymer degradation in acidic peatlands by metatranscriptomic analysis.

    PubMed

    Ivanova, Anastasia A; Wegner, Carl-Eric; Kim, Yongkyu; Liesack, Werner; Dedysh, Svetlana N

    2016-10-01

    Northern peatlands play a crucial role in the global carbon balance, serving as a persistent sink for atmospheric CO2 and a global carbon store. Their most extensive type, Sphagnum-dominated acidic peatlands, is inhabited by microorganisms with poorly understood degradation capabilities. Here, we applied a combination of barcoded pyrosequencing of SSU rRNA genes and Illumina RNA-Seq of total RNA (metatranscriptomics) to identify microbial populations and enzymes involved in degrading the major components of Sphagnum-derived litter and exoskeletons of peat-inhabiting arthropods: cellulose, xylan, pectin and chitin. Biopolymer addition to peat induced a threefold to fivefold increase in bacterial cell numbers. Functional community profiles of assembled mRNA differed between experimental treatments. In particular, pectin and xylan triggered increased transcript abundance of genes involved in energy metabolism and central carbon metabolism, such as glycolysis and TCA cycle. Concurrently, the substrate-induced activity of bacteria on these two biopolymers stimulated grazing of peat-inhabiting protozoa. Alveolata (ciliates) was the most responsive protozoa group as confirmed by analysis of both SSU rRNA genes and SSU rRNA. A stimulation of alphaproteobacterial methanotrophs on pectin was consistently shown by rRNA and mRNA data. Most likely, their significant enrichment was due to the utilization of methanol released during the degradation of pectin. Analysis of SSU rRNA and total mRNA revealed a specific response of Acidobacteria and Actinobacteria to chitin and pectin, respectively. Relatives of Telmatobacter bradus were most responsive among the Acidobacteria, while the actinobacterial response was primarily affiliated with Frankiales and Propionibacteriales. The expression of a wide repertoire of carbohydrate-active enzymes (CAZymes) corresponded well to the detection of a highly diverse peat-inhabiting microbial community, which is dominated by yet uncultivated

  12. Natural Xanthones

    NASA Astrophysics Data System (ADS)

    Denisova-Dyatlova, O. A.; Glyzin, V. I.

    1982-10-01

    The available information on the abundance of natural xanthones in nature and the methods for the determination of their structure, biogenesis, and pharmacological properties is surveyed and described systematically. The bibliography includes 151 references.

  13. Revisiting human natural killer cell subset function revealed cytolytic CD56dimCD16+ NK cells as rapid producers of abundant IFN-γ on activation

    PubMed Central

    De Maria, Andrea; Bozzano, Federica; Cantoni, Claudia; Moretta, Lorenzo

    2011-01-01

    The two major functions of human natural killer (NK) cells are conventionally associated with distinct cell subsets. Thus, cytolytic activity is mostly confined to the CD56dimCD16+ subset, whereas cytokine production is generally assigned to CD56brightCD16+/− cells. In this study, we reevaluated the functional capabilities of these NK subsets with regard to the production of IFN-γ at different time points after cell triggering via NKp46 and NKp30 activating receptors. Different from previous studies, cytokine production was also assessed at early intervals. We show that CD56dim NK cells produce IFN-γ already at 2 to 4 h, whereas no cytokine production is detected beyond 16 h. In contrast, CD56bright cells release IFN-γ only at late time intervals (>16 h after stimulation). The rapid IFN-γ production by CD56dim NK cells is in line with the presence of IFN-γ mRNA in freshly isolated cells. Rapid IFN-γ production was also induced by combinations of IL-2, IL-12, and IL-15. Our data indicate that not only cytolytic activity but also early IFN-γ production is a functional property of CD56dim NK cells. Thus, this subset can assure a rapid and comprehensive NK cell intervention during the early phases of innate responses. PMID:21187373

  14. Relative stability of major types of beta-turns as a function of amino acid composition: a study based on Ab initio energetic and natural abundance data.

    PubMed

    Perczel, András; Jákli, Imre; McAllister, Michael A; Csizmadia, Imre G

    2003-06-06

    Folding properties of small globular proteins are determined by their amino acid sequence (primary structure). This holds both for local (secondary structure) and for global conformational features of linear polypeptides and proteins composed from natural amino acid derivatives. It thus provides the rational basis of structure prediction algorithms. The shortest secondary structure element, the beta-turn, most typically adopts either a type I or a type II form, depending on the amino acid composition. Herein we investigate the sequence-dependent folding stability of both major types of beta-turns using simple dipeptide models (-Xxx-Yyy-). Gas-phase ab initio properties of 16 carefully selected and suitably protected dipeptide models (for example Val-Ser, Ala-Gly, Ser-Ser) were studied. For each backbone fold most probable side-chain conformers were considered. Fully optimized 321G RHF molecular structures were employed in medium level [B3LYP/6-311++G(d,p)//RHF/3-21G] energy calculations to estimate relative populations of the different backbone conformers. Our results show that the preference for beta-turn forms as calculated by quantum mechanics and observed in Xray determined proteins correlates significantly.

  15. Detection and structural identification of dissolved organic matter in Antarctic glacial ice at natural abundance by SPR-W5-WATERGATE 1H NMR spectroscopy.

    PubMed

    Pautler, Brent G; Simpson, André J; Simpson, Myrna J; Tseng, Li-Hong; Spraul, Manfred; Dubnick, Ashley; Sharp, Martin J; Fitzsimons, Sean J

    2011-06-01

    Dissolved organic matter (DOM) is ubiquitous in aquatic ecosystems and is derived from various inputs that control its turnover. Glaciers and ice sheets are the second largest water reservoir in the global hydrologic cycle, but little is known about glacial DOM composition or contributions to biogeochemical cycling. Here we employ SPR-W5-WATERGATE (1)H NMR spectroscopy to elucidate and quantify the chemical structures of DOM constituents in Antarctic glacial ice as they exist in their natural state (average DOC of 8 mg/L) without isolation or preconcentration. This Antarctic glacial DOM is predominantly composed of a mixture of small recognizable molecules differing from DOM in marine, lacustrine, and other terrestrial environments. The major constituents detected in three distinct types of glacial ice include lactic and formic acid, free amino acids, and a mixture of simple sugars and amino sugars with concentrations that vary between ice types. The detection of free amino acid and amino sugar monomer components of peptidoglycan within the ice suggests that Antarctic glacial DOM likely originates from in situ microbial activity. As these constituents are normally considered to be biologically labile (fast cycling) in nonglacial environments, accelerated glacier melt and runoff may result in a flux of nutrients into adjacent ecosystems.

  16. Assessment of marine-derived nutrients in the Copper River Delta, Alaska, using natural abundance of the stable isotopes of nitrogen, sulfur, and carbon

    USGS Publications Warehouse

    Kline, Thomas C.; Woody, Carol Ann; Bishop, Mary Anne; Powers, Sean P.; Knudsen, E. Eric

    2007-01-01

    We performed nitrogen, sulfur, and carbon stable isotope analysis (SIA) on maturing and juvenile anadromous sockeye and coho salmon, and periphyton in two Copper River delta watersheds of Alaska to trace salmonderived nutrients during 2003–2004. Maturing salmon were isotopically enriched relative to alternate freshwater N, S, and C sources as expected, with differences consistent with species trophic level differences, and minor system, sex, and year-to-year differences, enabling use of SIA to trace these salmon-derived nutrients. Periphyton naturally colonized, incubated, and collected using Wildco Periphtyon Samplers in and near spawning sites was 34S- and 15N-enriched, as expected, and at all freshwater sites was 13C-depleted. At nonspawning and coho-only sites, periphyton 34S and 15N was generally low. However, 34S was low enough at some sites to be suggestive of sulfate reduction, complicating the use of S isotopes. Juvenile salmon SIA ranged in values consistent with using production derived from re-mineralization as well as direct utilization, but only by a minority fraction of coho salmon. Dependency on salmon-derived nutrients ranged from relatively high to relatively low, suggesting a space-limited system. No one particular isotope was found to be superior for determining the relative importance of salmon-derived nutrients.

  17. Mobility Enhancement of Red Blood Cells with Biopolymers

    NASA Astrophysics Data System (ADS)

    Tahara, Daiki; Oikawa, Noriko; Kurita, Rei

    2016-03-01

    Adhesion of red blood cells (RBC) to substrates are one of crucial problems for a blood clot. Here we investigate the mobility of RBC between two glass substrates in saline with polymer systems. We find that RBCs are adhered to the glass substrate with PEG, however the mobility steeply increases with fibrinogen and dextran, which are biopolymers. We also find that the mobility affects an aggregation dynamics of RBCs, which is related with diseases such as influenza, blood clot and so on. The Brownian motion helps to increase probability of contact with each other and to find a more stable condition of the aggregation. Thus the biopolymers play important roles not only for preventing the adhesion but also for the aggregation.

  18. Mucin biopolymers as broad-spectrum antiviral agents

    PubMed Central

    Lieleg, Oliver; Lieleg, Corinna; Bloom, Jesse; Buck, Christopher B.; Ribbeck, Katharina

    2012-01-01

    Mucus is a porous biopolymer matrix that coats all wet epithelia in the human body and serves as the first line of defense against many pathogenic bacteria and viruses. However, under certain conditions viruses are able to penetrate this infection barrier, which compromises the protective function of native mucus. Here, we find that isolated porcine gastric mucin polymers, key structural components of native mucus, can protect an underlying cell layer from infection by small viruses such as human papillomavirus (HPV), Merkel cell polyomavirus (MCV), or a strain of influenza A virus. Single particle analysis of virus mobility inside the mucin barrier reveals that this shielding effect is in part based on a retardation of virus diffusion inside the biopolymer matrix. Our findings suggest that purified mucins may be used as a broad-range antiviral supplement to personal hygiene products, baby formula or lubricants to support our immune system. PMID:22475261

  19. Recent synchrotron radiation microdiffraction experiments on polymer and biopolymer fibers.

    PubMed

    Riekel, C; García Gutiérrez, M C; Gourrier, A; Roth, S

    2003-07-01

    The status of synchrotron radiation (SR) microdiffraction techniques developed at the ID13 beamline of the European Synchrotron Radiation Facility (ESRF) is reviewed for polymer and biopolymer fiber applications. Beam sizes in the micrometer-range have been used to study the local structure of whole fibers such as viscose-rayon or poly(p-phenylene terephthalamide). The possibilities for in situ studies during stretching, extrusion, or indentation will be discussed.

  20. Application of Raman spectroscopy method for analysis of biopolymer materials

    NASA Astrophysics Data System (ADS)

    Timchenko, Elena V.; Timchenko, Pavel E.; Volchkov, S. E.; Mahortova, Alexsandra O.; Asadova, Anna A.; Kornilin, Dmitriy V.

    2016-10-01

    This work presents the results of spectral analysis of biopolymer materials that are implemented in medical sphere. Polymer samples containing polycaprolactone and iron oxides of different valence were used in the studies. Raman spectroscopy method was used as a main control method. Relative content of iron and polycaprolactone in studied materials was assessed using ratio of RS intensities values at 604 cm-1 and 1726 cm-1 wavenumbers to intensity value of 1440 cm-1 line.

  1. Detailed electrical measurements on sago starch biopolymer solid electrolyte

    NASA Astrophysics Data System (ADS)

    Singh, Rahul; Baghel, Jaya; Shukla, S.; Bhattacharya, B.; Rhee, Hee-Woo; Singh, Pramod K.

    2014-12-01

    The biopolymer solid electrolyte has been synthesized and characterized. Potassium iodide (KI) has been added in polymer matrix to develop solid polymer electrolyte. Relationships between electrical, ionic transport parameter and mechanism have been studied in detail. Impedance spectroscopy reveals the detailed electrical studies and ion transport mechanism. The ion dissociation factor is compared with a measured dielectric constant at a fixed frequency. The dielectric data are calculated which support the ionic conductivity data.

  2. 13C Natural Abundance of Serum Retinol Is a Novel Biomarker for Evaluating Provitamin A Carotenoid-Biofortified Maize Consumption in Male Mongolian Gerbils123

    PubMed Central

    Pungarcher, India; Mourao, Luciana; Davis, Christopher R; Simon, Philipp; Pixley, Kevin V; Tanumihardjo, Sherry A

    2016-01-01

    Background: Crops such as maize, sorghum, and millet are being biofortified with provitamin A carotenoids to ensure adequate vitamin A (VA) intakes. VA assessment can be challenging because serum retinol concentrations are homeostatically controlled and more sensitive techniques are resource-intensive. Objectives: We investigated changes in serum retinol relative differences of isotope amount ratios of 13C/12C (δ13C) caused by natural 13C fractionation in C3 compared with C4 plants as a biomarker to detect provitamin A efficacy from biofortified (orange) maize and high-carotene carrots. Methods: The design was a 2 × 2 × 2 maize (orange compared with white) by carrot (orange compared with white) by a VA fortificant (VA+ compared with VA−) in weanling male Mongolian gerbils (n = 55), which included a 14-d VA depletion period and a 62-d treatment period (1 baseline and 8 treatment groups; n = 5−7/group). Liver VA and serum retinol were quantified, purified by HPLC, and analyzed by GC combustion isotope ratio mass spectrometry for 13C. Results: Treatments affected liver VA concentrations (0.048 ± 0.039 to 0.79 ± 0.24 μmol/g; P < 0.0001) but not overall serum retinol concentrations (1.38 ± 0.22 μmol/L). Serum retinol and liver VA δ13C were significantly correlated (R2 = 0.92; P < 0.0001). Serum retinol δ13C differentiated control groups that consumed white maize and white carrots (−27.1 ± 1.2 δ13C‰) from treated groups that consumed orange maize and white carrots (−21.6 ± 1.4 δ13C‰ P < 0.0001) and white maize and orange carrots (−30.6 ± 0.7 δ13C‰ P < 0.0001). A prediction model demonstrated the relative contribution of orange maize to total dietary VA for groups that consumed VA from mixed sources. Conclusions: Provitamin A efficacy and quantitative estimation of the relative contribution to dietary VA were demonstrated with the use of serum retinol δ13C. This method could be used for maize efficacy or effectiveness studies and with

  3. A review of semi-synthetic biopolymer complexes: modified polysaccharide nano-carriers for enhancement of oral drug bioavailability.

    PubMed

    Sithole, Mduduzi N; Choonara, Yahya E; du Toit, Lisa C; Kumar, Pradeep; Pillay, Viness

    2017-03-01

    Semi-synthetic biopolymer complexes (SSBCs) have potential as nano-carriers for oral drug delivery due to their exceptional properties obtained by merging the properties of synthetic (e.g. good thermal and mechanical properties) with natural polymers (e.g. biocompatibility); thus, forming a new class of biopolymer materials incorporating the best of both worlds. Despite development in drug delivery systems, oral administration of therapeutic agent is still preferred. Several nano-polymeric systems has been prepared and characterized based on both synthetic polymers and natural polymers, each with its limitations and advantages. Among natural polymers, alginate, chitosan, and hyaluronic acid (HA) have been studied broadly for the fabrication of nanoparticles systems. This review discusses a newly investigated class of polymer called SSBCs as oral drug nano-carriers. It also discusses certain significant structural and functional attributes or effects which are essential to be taken into consideration when an oral drug delivery system is developed. The review is aimed at describing complexation of few natural polymers (e.g. polysaccharides) with selected synthetic polymers or synthetic chemicals to indicate some of the factors that influence preparation, solubility, formation, and stability of these SSBCs.

  4. Natural-abundance 15N NMR studies of Turkey ovomucoid third domain. Assignment of peptide 15N resonances to the residues at the reactive site region via proton-detected multiple-quantum coherence

    NASA Astrophysics Data System (ADS)

    Ortiz-Polo, Gilberto; Krishnamoorthi, R.; Markley, John L.; Live, David H.; Davis, Donald G.; Cowburn, David

    Heteronuclear two-dimensional 1H{ 15N} multiple-quantum (MQ) spectroscopy has been applied to a protein sample at natural abundance: ovomucoid third domain from turkey ( Meleagris gallopavo), a serine proteinase inhibitor of 56 amino acid residues. Peptide amide 1H NMR assignments obtained by two-dimensional 1H{ 1H} NMR methods (R. Krishnamoorthi and J. L. Markley, unpublished data) led to identification of the corresponding 1H{ 15N} MQ coherence cross peaks. From these, 15N NMR chemical shifts were determined for several specific backbone amide groups of amino acid residues located around the reactive site region of the inhibitor. The results suggest that amide 15N chemical shifts, which are readily obtained in this way, may serve as sensitive probes for conformational studies of proteins.

  5. Proton-detected 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H-1H RFDR mixing on a natural abundant sample under ultrafast MAS

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Nishiyama, Yusuke

    2015-09-01

    In this contribution, we have demonstrated a proton detection-based approach on a natural abundant powdered L-Histidine HCl-H2O sample at ultrafast magic angle spinning (MAS) to accomplish 14N/14N correlation from a 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H finite-pulse radio frequency-driven recoupling (fp-RFDR). Herein the heteronuclear magnetization transfer between 14N and 1H has been achieved by HMQC experiment, whereas 14N/14N correlation is attained through enhanced 1H-1H spin diffusion process due to 1H-1H dipolar recoupling during the RFDR mixing. While the use of ultrafast MAS (90 kHz) provides sensitivity enhancement through increased 1H transverse relaxation time (T2), the use of micro-coil probe which can withstand strong 14N radio frequency (RF) fields further improves the sensitivity per unit sample volume.

  6. Human and climate impact on ¹⁵N natural abundance of plants and soils in high-mountain ecosystems: a short review and two examples from the Eastern Pamirs and Mt. Kilimanjaro.

    PubMed

    Zech, Michael; Bimüller, Carolin; Hemp, Andreas; Samimi, Cyrus; Broesike, Christina; Hörold, Claudia; Zech, Wolfgang

    2011-09-01

    Population pressure increasingly endangers high-mountain ecosystems such as the pastures in the Eastern Pamirs and the mountain forests on Mt. Kilimanjaro. At the same time, these ecosystems constitute the economic basis for millions of people living there. In our study, we, therefore, aimed at characterising the land-use effects on soil degradation and N-cycling by determining the natural abundance of (15)N. A short review displays that δ(15)N of plant-soil systems may often serve as an integrated indicator of N-cycles with more positive δ(15)N values pointing towards N-losses. Results for the high-mountain pastures in the Eastern Pamirs show that intensively grazed pastures are significantly enriched in (15)N compared to the less-exploited pastures by 3.5 ‰, on average. This can be attributed to soil organic matter degradation, volatile nitrogen losses, nitrogen leaching and a general opening of the N-cycle. Similarly, the intensively degraded savanna soils, the cultivated soils and the soils under disturbed forests on the foothill of Mt. Kilimanjaro reveal very positive δ(15)N values around 6.5 ‰. In contrast, the undisturbed forest soils in the montane zone are more depleted in (15)N, indicating that here the N-cycle is relatively closed. However, significantly higher δ(15)N values characterise the upper montane forest zone at the transition to the subalpine zone. We suggest that this reflects N-losses by the recently monitored and climate change and antropogenically induced increasing fire frequency pushing the upper montane rainforest boundary rapidly downhill. Overall, we conclude that the analysis of the (15)N natural abundance in high-mountain ecosystems is a purposeful tool for detecting land-use- or climate change-induced soil degradation and N-cycle opening.

  7. In Situ Natural Abundance 17 O and 25 Mg NMR Investigation of Aqueous Mg(OH) 2 Dissolution in the Presence of Supercritical CO 2

    SciTech Connect

    Hu, Mary Y.; Deng, Xuchu; Thanthiriwatte, K. Sahan; Jackson, Virgil E.; Wan, Chuan; Qafoku, Odeta; Dixon, David A.; Felmy, Andrew R.; Rosso, Kevin M.; Hu, Jian Zhi

    2016-11-15

    We report the development of an in situ high pressure NMR capability that permits natural abundance 17O and 25Mg NMR characterization of dissolved species in aqueous solution and in the presence of supercritical CO2 fluid (scCO2). The dissolution of Mg(OH)2 (brucite) in a multiphase water/scCO2 fluid at 90 atm pressure and 50 C was studied in situ, with relevance to geological carbon sequestration. 17O NMR spectra allowed identification and distinction of various fluid species including dissolved CO2 in the H2O-rich phase, scCO2, aqueous H2O, and HCO3-. The widely separated spectral peaks for various species can all be observed both dynamically and quantitatively at concentrations of as low as 20 mM. Measurement of the concentrations of these individual species also allows an in situ estimate of the hydrogen ion concentration, or pCH+ values, of the reacting solutions. The concentration of Mg2+ can be observed by natural abundance 25Mg NMR at a concentration as low as 10 mM. Quantum chemistry calculations of the NMR chemical shifts on cluster models aided in the interpretation of the experimental results. Evidence for the formation of polymeric Mg2+ clusters at high concentrations in the H2O-rich phase, a possible critical step needed for magnesium carbonate formation, was found. The approach and findings enable insight into metal carbonation reactions associated with geological carbon sequestration that cannot be probed by ex situ methods.

  8. Effect of organic matter on estuarine flocculation: a laboratory study using montmorillonite, humic acid, xanthan gum, guar gum and natural estuarine flocs

    PubMed Central

    2014-01-01

    Background Riverine particles undergo a rapid transformation when they reach estuaries. The rapid succession of hydrodynamic and biogeochemical regimes forces the particles to flocculate, settle and enter the sediment pool. The rates and magnitudes of flocculation depend on the nature of the particles which are primarily affected by the types and quantities of organic matter (OM). Meanwhile, the OM characteristics vary widely between environments, as well as within a single environment due to seasonal climate and land use variability. We investigated the effect of the OM types and quantities through laboratory experiments using natural estuarine particles from the Mississippi Sound and Atchafalaya Bay as well as model mixtures of montmorillonite and organic molecules (i.e., biopolymers (guar/xanthan gums) and humic acid). Results Biopolymers promote flocculation but the magnitude depends on the types and quantities. Nonionic guar gum yields much larger flocs than anionic xanthan gum, while both of them exhibit a nonlinear behavior in which the flocculation is the most pronounced at the intermediate OM loading. Moreover, the effect of guar gum is independent of salinity whereas the effect of xanthan gum is pronounced at higher salinity. Meanwhile, humic acid does not affect flocculation at all salinity values tested in this study. These results are echoed in the laboratory manipulation of the natural estuarine particles. Flocculation of the humic acid-rich Mississippi Sound particles is unaffected by the OM, whereas that of biopolymer-rich Atchafalaya Bay particles is enhanced by the OM. Conclusions Flocculation is positively influenced by the presence of biopolymers that are produced as the result of marine primary production. Meanwhile, humic acid, which is abundant in the rivers that drain the agricultural soils of Southeastern United States, has little influence on flocculation. Thus, it is expected that humic acid-poor riverine particles (e.g., Mississippi

  9. Advanced Coatings from Natural-Based Polymers for Metals

    DTIC Science & Technology

    2000-07-01

    polysaccharide biopolymers originating from pectin, starch , and chitosan as renewable agricultural and marine resources, and on assessing their potential as the...excellent salt-spray resistance. 14. SUBJECT TERMS 15. NUMBER IF PAGES Coating, Corrosion, Aluminum, Biopolymer, Starch , Chitosan 7 16. PRICE CODE 17...The natural polymers used in this program were the corn-or potato- starch and crab or shrimp shells-chitosan obtained from renewable agricultural and

  10. Introduction of soft X-ray spectromicroscopy as an advanced technique for plant biopolymers research.

    PubMed

    Karunakaran, Chithra; Christensen, Colleen R; Gaillard, Cedric; Lahlali, Rachid; Blair, Lisa M; Perumal, Vijayan; Miller, Shea S; Hitchcock, Adam P

    2015-01-01

    Soft X-ray absorption spectroscopy coupled with nano-scale microscopy has been widely used in material science, environmental science, and physical sciences. In this work, the advantages of soft X-ray absorption spectromicroscopy for plant biopolymer research were demonstrated by determining the chemical sensitivity of the technique to identify common plant biopolymers and to map the distributions of biopolymers in plant samples. The chemical sensitivity of soft X-ray spectroscopy to study biopolymers was determined by recording the spectra of common plant biopolymers using soft X-ray and Fourier Transform mid Infrared (FT-IR) spectroscopy techniques. The soft X-ray spectra of lignin, cellulose, and polygalacturonic acid have distinct spectral features. However, there were no distinct differences between cellulose and hemicellulose spectra. Mid infrared spectra of all biopolymers were unique and there were differences between the spectra of water soluble and insoluble xylans. The advantage of nano-scale spatial resolution exploited using soft X-ray spectromicroscopy for plant biopolymer research was demonstrated by mapping plant cell wall biopolymers in a lentil stem section and compared with the FT-IR spectromicroscopy data from the same sample. The soft X-ray spectromicroscopy enables mapping of biopolymers at the sub-cellular (~30 nm) resolution whereas, the limited spatial resolution in the micron scale range in the FT-IR spectromicroscopy made it difficult to identify the localized distribution of biopolymers. The advantages and limitations of soft X-ray and FT-IR spectromicroscopy techniques for biopolymer research are also discussed.

  11. Helix-like biopolymers can act as dampers of force for bacteria in flows.

    PubMed

    Zakrisson, Johan; Wiklund, Krister; Axner, Ove; Andersson, Magnus

    2012-06-01

    Biopolymers are vital structures for many living organisms; for a variety of bacteria, adhesion polymers play a crucial role for the initiation of colonization. Some bacteria express, on their surface, attachment organelles (pili) that comprise subunits formed into stiff helix-like structures that possess unique biomechanical properties. These helix-like structures possess a high degree of flexibility that gives the biopolymers a unique extendibility. This has been considered beneficial for piliated bacteria adhering to host surfaces in the presence of a fluid flow. We show in this work that helix-like pili have the ability to act as efficient dampers of force that can, for a limited time, lower the load on the force-mediating adhesin-receptor bond on the tip of an individual pilus. The model presented is applied to bacteria adhering with a single pilus of either of the two most common types expressed by uropathogenic Escherichia coli, P or type 1 pili, subjected to realistic flows. The results indicate that for moderate flows (~25 mm/s) the force experienced by the adhesin-receptor interaction at the tip of the pilus can be reduced by a factor of ~6 and ~4, respectively. The uncoiling ability provides a bacterium with a "go with the flow" possibility that acts as a damping. It is surmised that this can be an important factor for the initial part of the adhesion process, in particular in turbulent flows, and thereby be of use for bacteria in their striving to survive a natural defense such as fluid rinsing actions.

  12. Micro-Heterogeneity of Cellulosic Fiber Biopolymer Prepared from Corn Hulls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Z-trim is a zero calorie cellulosic fiber biopolymer produced from corn hulls. The micro-structural heterogeneities of Z-trim biopolymer were investigated by monitoring the thermally driven displacements of well-dispersed micro-spheres via video fluorescence microscopy named multiple-particle track...

  13. Micro-heterogeneity of Cellulosic Fiber Biopolymer Prepared from Corn Hulls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Z-trim is a zero calorie cellulosic fiber biopolymer produced from corn hulls. The micro-structural heterogeneities of Z-trim biopolymer were investigated by monitoring the thermally driven displacements of well-dispersed micro-spheres via video fluorescence microscopy named multiple-particle track...

  14. The wear of two orthopaedic biopolymers against each other.

    PubMed

    Joyce, T J

    2005-01-01

    The potential for all-polymer prostheses has not been widely investigated. It might be expected that the wear of such biomaterial combinations would be excessive, but an in vivo study of all polymer knee prostheses reported that there were no failures due to wear, even after ten years of clinical use. This design of knee prosthesis used polyacetal and ultra high molecular weight polyethylene (UHMWPE) as the biopolymers. Similarly, an earlier in vitro study of polyacetal and UHMWPE hip prostheses indicated lower wear than for a cobalt chrome and UHMWPE combination. Therefore this study set out to test the poly-acetal and UHMWPE combination in a wear screening rig which had previously been validated against clinical data for artificial hip joints. Two different motion conditions were applied to the test samples and each biopolymer was tested as both pin and plate. Interestingly it was found that, whatever the contribution from pin or plate, the total mean wear factors were 1.5 10 -6 mm 3/Nm under reciprocation-only, and 4.1 10 -6 mm 3 /Nm under multi-directional motion. These wear factors were greater than those found when a conventional metal-on-UHMWPE couple was tested under the same loading, motion and lu-bricant conditions. A comparison was also undertaken with the wear of other orthopaedic biopolymer combinations, namely cross-linked polyethylene (XLPE) against itself, and UHMWPE against itself. The XLPE pairing showed somewhat lower wear than the polyacetal and UHMWPE couple, while the UHMWPE pairing showed the highest wear of all, approximately an or-der of magnitude greater than the polyacetal and UHMWPE combination.

  15. Scaling Equations for a Biopolymer in Salt Solution

    NASA Astrophysics Data System (ADS)

    Geissler, Erik; Hecht, Anne-Marie; Horkay, Ferenc

    2007-12-01

    The effect of the simultaneous presence of monovalent and divalent cations on the thermodynamics of polyelectrolyte solutions is an incompletely solved problem. In physiological conditions, combinations of these ions affect structure formation in biopolymer systems. Dynamic light scattering measurements of the collective diffusion coefficient D and the osmotic compressibility of semidilute hyaluronan solutions containing different ratios of sodium and calcium ions are compared with simple polyelectrolyte models. Scaling relationships are proposed in terms of polymer concentration and ionic strength J of the added salt. Differences in the effects of sodium and calcium ions are found to be expressed only through J.

  16. Peptide-based Biopolymers in Biomedicine and Biotechnology

    PubMed Central

    Chow, Dominic; Nunalee, Michelle L.; Lim, Dong Woo; Simnick, Andrew J.; Chilkoti, Ashutosh

    2008-01-01

    Peptides are emerging as a new class of biomaterials due to their unique chemical, physical, and biological properties. The development of peptide-based biomaterials is driven by the convergence of protein engineering and macromolecular self-assembly. This review covers the basic principles, applications, and prospects of peptide-based biomaterials. We focus on both chemically synthesized and genetically encoded peptides, including poly-amino acids, elastin-like polypeptides, silk-like polymers and other biopolymers based on repetitive peptide motifs. Applications of these engineered biomolecules in protein purification, controlled drug delivery, tissue engineering, and biosurface engineering are discussed. PMID:19122836

  17. Mechanically induced helix-coil transition in biopolymer networks.

    PubMed

    Courty, Sebastien; Gornall, Joanne L; Terentjev, Eugene M

    2006-02-01

    The quasi-equilibrium evolution of the helical fraction occurring in a biopolymer network (gelatin gel) under an applied stress has been investigated by observing modulation in its optical activity. Its variation with the imposed chain extension is distinctly nonmonotonic and corresponds to the transition of initially coiled strands to induced left-handed helices. The experimental results are in qualitative agreement with theoretical predictions of helices induced on chain extension. This new effect of mechanically stimulated helix-coil transition has been studied further as a function of the elastic properties of the polymer network: crosslink density and network aging.

  18. Microfluidic generation and selective degradation of biopolymer-based Janus microbeads.

    PubMed

    Marquis, Mélanie; Renard, Denis; Cathala, Bernard

    2012-04-09

    We describe a microfluidic approach for generating Janus microbeads from biopolymer hydrogels. A flow-focusing device was used to emulsify the coflow of aqueous solutions of one or two different biopolymers in an organic phase to synthesize homo or hetero Janus microbeads. Biopolymer gelation was initiated, in the chip, by diffusion-controlled ionic cross-linking of the biopolymers. Pectin-pectin (homo Janus) and, for the first time, pectin-alginate (hetero Janus) microbeads were produced. The efficiency of separation of the two hemispheres, which reflected mixing and convection phenomena, was investigated by confocal scanning laser microscopy (CSLM) of previously labeled biopolymers. The interface of the hetero Janus structure was clearly defined, whereas that of the homo Janus microbeads was poorly defined. The Janus structure was confirmed by subjecting each microbead hemisphere to specific enzymatic degradation. These new and original microbeads from renewable resources will open up opportunities for studying relationships between combined enzymatic hydrolysis and active compound release.

  19. Simulating microbiologically influenced corrosion by depositing extracellular biopolymers on mild steel surfaces

    SciTech Connect

    Roe, F.L.; Lewandowski, Z.; Funk, T.

    1996-10-01

    Electrochemical properties of corroding mild steel (MS) surfaces were measured in real time using three closely spaced microelectrodes. Dissolved oxygen, pH, and ion currents were mapped simultaneously and noninvasively above a MS coupon partially coated with biopolymer gels. Calcium alginate (Ca-Alg [an extracellular biopolymer containing carboxylate functional groups]) and agarose (one without carboxylate functional groups) were tested. Corrosion occurred at approximately the same rate under the two biopolymer spots on the same coupon. Corrosion rates under these biopolymers were {approx} 4 mpy in a weak saline solution. Results suggested corrosion was not influenced by chemical properties of the biopolymer but possibly was controlled by oxygen reduction in noncoated regions of the coupon (i.e., a differential aeration cell).

  20. Diterpenoid biopolymers: new directions for renewable materials engineering.

    PubMed

    Hillwig, Matthew L; Mann, Francis M; Peters, Reuben J

    2011-02-01

    Most types of ambers are naturally occurring, relatively hard, durable resinite polymers derived from the exudates of trees. This resource has been coveted for thousands of years due to its numerous useful properties in industrial processes, beauty, and purported medicinal properties. Labdane diterpenoid-based ambers represent the most abundant and important resinites on earth. These resinites are a dwindling nonrenewable natural resource, so a new source of such materials needs to be established. Recent advances in sequencing technologies and biochemical engineering are rapidly accelerating the rate of identifying and assigning function to genes involved in terpenoid biosynthesis, as well as producing industrial-scale quantities of desired small-molecules in bacteria and yeast. This has provided new tools for engineering metabolic pathways capable of producing diterpenoid monomers that will enable the production of custom-tailored resinite-like polymers. Furthermore, this biosynthetic toolbox is continuously expanding, providing new possibilities for renewing dwindling stocks of naturally occurring resinite materials and engineering new materials for future applications.

  1. P and S wave responses of bacterial biopolymer formation in unconsolidated porous media

    NASA Astrophysics Data System (ADS)

    Noh, Dong-Hwa; Ajo-Franklin, Jonathan B.; Kwon, Tae-Hyuk; Muhunthan, Balasingam

    2016-04-01

    This study investigated the P and S wave responses and permeability reduction during bacterial biopolymer formation in unconsolidated porous media. Column experiments with fine sands, where the model bacteria Leuconostoc mesenteroides were stimulated to produce insoluble biopolymer, were conducted while monitoring changes in permeability and P and S wave responses. The bacterial biopolymer reduced the permeability by more than 1 order of magnitude, occupying ~10% pore volume after 38 days of growth. This substantial reduction was attributed to the bacterial biopolymer with complex internal structures accumulated at pore throats. S wave velocity (VS) increased by more than ~50% during biopolymer accumulation; this indicated that the bacterial biopolymer caused a certain level of stiffening effect on shear modulus of the unconsolidated sediment matrix at low confining stress conditions. Whereas replacing pore water by insoluble biopolymer was observed to cause minimal changes in P wave velocity (VP) due to the low elastic moduli of insoluble biopolymer. The spectral ratio analyses revealed that the biopolymer formation caused a ~50-80% increase in P wave attenuation (1/QP) at the both ultrasonic and subultrasonic frequency ranges, at hundreds of kHz and tens of kHz, respectively, and a ~50-60% increase in S wave attenuation (1/QS) in the frequency band of several kHz. Our results reveal that in situ biopolymer formation and the resulting permeability reduction can be effectively monitored by using P and S wave attenuation in the ultrasonic and subultrasonic frequency ranges. This suggests that field monitoring using seismic logging techniques, including time-lapse dipole sonic logging, may be possible.

  2. Nature of bonding in complexes containing "supershort" metal-metal bonds. raman and theoretical study of M2(dmp)4 [M = Cr (natural abundance Cr, 50Cr, and 54Cr) and Mo; dmp = 2,6-dimethoxyphenyl].

    PubMed

    Da Re, Ryan E; Eglin, Judith L; Carlson, Christin N; John, Kevin D; Morris, David E; Woodruff, William H; Bailey, James A; Batista, Enrique; Martin, Richard L; Cotton, F Albert; Hillard, Elizabeth A; Murillo, Carlos A; Sattelberger, Alfred P; Donohoe, Robert J

    2010-02-17

    We report an investigation of complexes of the type M(2)(dmp)(4) (M = Mo, Cr; dmp = 2,6-dimethoxyphenyl) using resonance Raman (RR) spectroscopy, Cr isotopic substitution, and density functional theory (DFT) calculations. Assignment of the Mo-Mo stretching vibration in the Mo(2) species is straightforward, as evidenced by a single resonance-enhanced band at 424 cm(-1), consistent with an essentially unmixed metal-metal stretch, and overtones of this vibration. On the other hand, the Cr(2) congener has no obvious metal-metal stretching mode near 650-700 cm(-1), where empirical predictions based on the Cr-Cr distance as well as DFT calculations suggest that this vibration should appear if unmixed. Instead, three bands are observed at 345, 363, and 387 cm(-1) that (a) have relative RR intensities that are sensitive to the Raman excitation frequency, (b) exhibit overtones and combinations in the RR spectra, and (c) shift in frequency upon isotopic substitution ((50)Cr and (54)Cr). DFT calculations are used to model the vibrational data for the Mo(2) and Cr(2) systems. Both the DFT results and empirical predictions are in good agreement with experimental observations in the Mo(2) complex, but both, while mutually consistent, differ radically from experiment in the Cr(2) complex. Our experimental and theoretical results, especially the Cr isotope shifts, clearly demonstrate that the potential energy of the Cr-Cr stretching coordinate is distributed among several normal modes having both Cr-Cr and Cr-ligand character. The general significance of these results in interpreting spectroscopic observations in terms of the nature of metal-metal multiple bonding is discussed.

  3. Inorganic polyphosphate in the microbial world. Emerging roles for a multifaceted biopolymer.

    PubMed

    Albi, Tomás; Serrano, Aurelio

    2016-02-01

    Inorganic polyphosphates (polyP) are linear polymers of tens to hundreds orthophosphate residues linked by phosphoanhydride bonds. These fairly abundant biopolymers occur in all extant forms of life, from prokaryotes to mammals, and could have played a relevant role in prebiotic evolution. Since the first identification of polyP deposits as metachromatic or volutin granules in yeasts in the nineteenth century, an increasing number of varied physiological functions have been reported. Due to their "high energy" bonds analogous to those in ATP and their properties as polyanions, polyP serve as microbial phosphagens for a variety of biochemical reactions, as a buffer against alkalis, as a storage of Ca(2+) and as a metal-chelating agent. In addition, recent studies have revealed polyP importance in signaling and regulatory processes, cell viability and proliferation, pathogen virulence, as a structural component and chemical chaperone, and as modulator of microbial stress response. This review summarizes the current status of knowledge and future perspectives of polyP functions and their related enzymes in the microbial world.

  4. Direct adhesive measurements between wood biopolymer model surfaces.

    PubMed

    Gustafsson, Emil; Johansson, Erik; Wågberg, Lars; Pettersson, Torbjörn

    2012-10-08

    For the first time the dry adhesion was measured for an all-wood biopolymer system using Johnson-Kendall-Roberts (JKR) contact mechanics. The polydimethylsiloxane hemisphere was successfully surface-modified with a Cellulose I model surface using layer-by-layer assembly of nanofibrillated cellulose and polyethyleneimine. Flat surfaces of cellulose were equally prepared on silicon dioxide substrates, and model surfaces of glucomannan and lignin were prepared on silicon dioxide using spin-coating. The measured work of adhesion on loading and the adhesion hysteresis was found to be very similar between cellulose and all three wood polymers, suggesting that the interaction between these biopolymers do not differ greatly. Surface energy calculations from contact angle measurements indicated similar dispersive surface energy components for the model surfaces. The dispersive component was dominating the surface energy for all surfaces. The JKR work of adhesion was lower than that calculated from contact angle measurements, which partially can be ascribed to surface roughness of the model surfaces and overestimation of the surface energies from contact angle determinations.

  5. Nonlinear viscoelasticity and generalized failure criterion for biopolymer gels

    NASA Astrophysics Data System (ADS)

    Divoux, Thibaut; Keshavarz, Bavand; Manneville, Sébastien; McKinley, Gareth

    2016-11-01

    Biopolymer gels display a multiscale microstructure that is responsible for their solid-like properties. Upon external deformation, these soft viscoelastic solids exhibit a generic nonlinear mechanical response characterized by pronounced stress- or strain-stiffening prior to irreversible damage and failure, most often through macroscopic fractures. Here we show on a model acid-induced protein gel that the nonlinear viscoelastic properties of the gel can be described in terms of a 'damping function' which predicts the gel mechanical response quantitatively up to the onset of macroscopic failure. Using a nonlinear integral constitutive equation built upon the experimentally-measured damping function in conjunction with power-law linear viscoelastic response, we derive the form of the stress growth in the gel following the start up of steady shear. We also couple the shear stress response with Bailey's durability criteria for brittle solids in order to predict the critical values of the stress σc and strain γc for failure of the gel, and how they scale with the applied shear rate. This provides a generalized failure criterion for biopolymer gels in a range of different deformation histories. This work was funded by the MIT-France seed fund and by the CNRS PICS-USA scheme (#36939). BK acknowledges financial support from Axalta Coating Systems.

  6. Permeability Modification Using a Reactive Alkaline-Soluble Biopolymer

    SciTech Connect

    Sandra L. Fox; Xina Xie; Greg Bala

    2004-11-01

    Polymer injection has been used in reservoirs to alleviate contrasting permeability zones to enhance oil recovery (EOR). Polymer technology relies mainly on the use of polyacrylamides cross-linked by a hazardous metal or organic. Contemporary polymer plugging has investigated the stimulation of in-situ microorganisms to produce polymers (Jenneman et. al., 2000) and the use of biocatalysts to trigger gelling (Bailey et. al., 2000). The use of biological polymers are advantageous in that they can block high permeability areas, are environmentally friendly, and have potential to form reversible gels without the use of hazardous cross-linkers. Recent efforts have produced a reactive alkaline-soluble biopolymer from Agrobacterium species ATCC # 31749 that gels upon decreasing the pH of the polymeric solution. Microbial polymers are of interest due to their potential cost savings, compared to conventional use of synthetic chemical polymers. Numerous microorganisms are known to produce extracellular polysaccharides. One microbiological polymer of interest is curdlan, â - (1, 3) glucan, which has demonstrated gelling properties by a reduction in pH. The focus of this study was to determine the impact an alkaline-soluble biopolymer can have on sandstone permeability.

  7. Associative Interactions in Crowded Solutions of Biopolymers Counteract Depletion Effects.

    PubMed

    Groen, Joost; Foschepoth, David; te Brinke, Esra; Boersma, Arnold J; Imamura, Hiromi; Rivas, Germán; Heus, Hans A; Huck, Wilhelm T S

    2015-10-14

    The cytosol of Escherichia coli is an extremely crowded environment, containing high concentrations of biopolymers which occupy 20-30% of the available volume. Such conditions are expected to yield depletion forces, which strongly promote macromolecular complexation. However, crowded macromolecule solutions, like the cytosol, are very prone to nonspecific associative interactions that can potentially counteract depletion. It remains unclear how the cytosol balances these opposing interactions. We used a FRET-based probe to systematically study depletion in vitro in different crowded environments, including a cytosolic mimic, E. coli lysate. We also studied bundle formation of FtsZ protofilaments under identical crowded conditions as a probe for depletion interactions at much larger overlap volumes of the probe molecule. The FRET probe showed a more compact conformation in synthetic crowding agents, suggesting strong depletion interactions. However, depletion was completely negated in cell lysate and other protein crowding agents, where the FRET probe even occupied slightly more volume. In contrast, bundle formation of FtsZ protofilaments proceeded as readily in E. coli lysate and other protein solutions as in synthetic crowding agents. Our experimental results and model suggest that, in crowded biopolymer solutions, associative interactions counterbalance depletion forces for small macromolecules. Furthermore, the net effects of macromolecular crowding will be dependent on both the size of the macromolecule and its associative interactions with the crowded background.

  8. Assessment of respiration activity and ecotoxicity of composts containing biopolymers.

    PubMed

    Kopeć, Michał; Gondek, Krzysztof; Baran, Agnieszka

    2013-03-01

    The research was conducted to determine if introducing biodegradable polymer materials to the composting process would affect selected biological properties of mature compost. Determination of biological properties of composts composed of testing their respiration activity and toxicity. Respiration activity was measured in material from the composting process by means of OxiTop Control measuring system. The ecotoxicity of composts was estimated by means of a set of biotests composed of three microbiotests using five test organisms. Introduction of polymer materials caused a decrease in respiration activity of mature compost. Similar dependencies as in the case of mass loss were registered. Compost to which a biodegradable polymer with the highest content of starch was added revealed the smallest difference in comparison with organic material composted without polymers. Lower content of starch in a polymer caused lower respiration activity of composts, whereas microorganism vaccine might have accelerated maturing of composts, thus contributing to the smallest respiration of compost. In composts containing biopolymers the following were observed: an increase in germination inhibition--2.5 times, roots growth inhibition--1.8 times, growth inhibition of Heterocypris incongruens--four times and luminescence inhibition of Vibrio fischeri--1.6 times in comparison with the control (compost K1). Composts containing biopolymers were classified as toxicity class III, whereas the compost without polymer addition as class II.

  9. Nano-Fibrous Biopolymer Hydrogels via Biological Conjugation for Osteogenesis.

    PubMed

    Chen, Huinan; Xing, Xiaodong; Jia, Yang; Mao, Jiahui; Zhang, Ziwei; Tan, Huaping

    2016-06-01

    Nanostructured biopolymer hydrogels have great potential in the field of drug delivery and regenerative medicine. In this work, a nano-fibrous (NF) biopolymer hydrogel was developed for cell growth factors (GFs) delivery and in vitro osteogenesis. The nano-fibrous hydrogel was produced via biological conjugation of streptavidin functionalized hyaluronic acid (HA-Streptavidin) and biotin terminated star-shaped poly(ethylene glycol) (PEG-Biotin). In the present work, in vitro gelation, mechanical properties, degradation and equilibrium swelling of the NF hydrogel were examined. The potential application of this NF gel scaffold in bone tissue engineering was confirmed by encapsulation behavior of osteoblasts. Osteoblasts seeded directly in NF gel scaffold containing cell growth factor, e.g. bone morphogenetic protein 2 (BMP-2), was to mimic the in vivo microenvironment in which cells interface biomaterials and interact with BMP-2. In combination with BMP-2, the NF hydrogel exhibited beneficial effects on osteoblast activity and differentiation, which suggested a promising future for local treatment of pathologies involving bone loss.

  10. Application of Natural Isotopic Abundance ¹H-¹³C- and ¹H-¹⁵N-Correlated Two-Dimensional NMR for Evaluation of the Structure of Protein Therapeutics.

    PubMed

    Arbogast, Luke W; Brinson, Robert G; Marino, John P

    2016-01-01

    Methods for characterizing the higher-order structure of protein therapeutics are in great demand for establishing consistency in drug manufacturing, for detecting drug product variations resulting from modifications in the manufacturing process, and for comparing a biosimilar to an innovator reference product. In principle, solution NMR can provide a robust approach for characterization of the conformation(s) of protein therapeutics in formulation at atomic resolution. However, molecular weight limitations and the perceived need for stable isotope labeling have to date limited its practical applications in the biopharmaceutical industry. Advances in NMR magnet and console technologies, cryogenically cooled probes, and new rapid acquisition methodologies, particularly selective optimized flip-angle short transient pulse schemes and nonuniform sampling, have greatly ameliorated these limitations. Here, we describe experimental methods for the collection and analysis of 2D (1)H(N)-(15)N-amide- and (1)H-(13)C-methyl-correlated spectra applied to protein drug products at natural isotopic abundance, including representatives from the rapidly growing class of monoclonal antibody (mAb) therapeutics. Practical aspects of experimental setup and data acquisition for both standard and rapid acquisition NMR techniques are described. Furthermore, strategies for the statistical comparison of 2D (1)H(N)-(15)N-amide- and (1)H-(13)C-methyl-correlated spectra are detailed.

  11. The natural abundance of 15N in plant and soil-available N indicates a shift of main plant N resources to NO3(-) from NH4(+) along the N leaching gradient.

    PubMed

    Takebayashi, Yu; Koba, Keisuke; Sasaki, Yuji; Fang, Yunting; Yoh, Muneoki

    2010-04-15

    To investigate which of ammonium (NH(4)(+)) or nitrate (NO(3)(-)) is used by plants at gradient sites with different nitrogen (N) availability, we measured the natural abundance of (15)N in foliage and soil extractable N. Hinoki cypress (Chamaecyparis obtusa Endlicher) planted broadly in Japan was selected for use in this study. We estimated the source proportion of foliar N (NH(4)(+) vs. NO(3)(-)) quantitatively using mass balance equations. The results showed that C. obtusa used mainly NH(4)(+) in N-limited forests, although the dependence of C. obtusa on NO(3)(-) was greater in other NO(3)(-)-rich forests. We regarded dissolved organic N (DON) as a potential N source because a previous study demonstrated that C. obtusa can take up glycine. Thus we added DON to our mass balance equations and calculated the source proportion using an isotope-mixing model (IsoSource model). The results still showed a positive correlation between the calculated plant N proportion of NO(3)(-) and the NO(3)(-) pool size in the soil, indicating that high NO(3)(-) availability increases the reliance of C. obtusa on NO(3)(-). Our data suggest the shift of the N source for C. obtusa from NH(4)(+) to NO(3)(-) according to the relative availability of NO(3)(-). They also show the potential of the foliar delta(15)N of C. obtusa as an indicator of the N status in forest ecosystems with the help of the delta(15)N values of soil inorganic and organic N.

  12. Natural melanin: a potential pH-responsive drug release device.

    PubMed

    Araújo, Marco; Viveiros, Raquel; Correia, Tiago R; Correia, Ilídio J; Bonifácio, Vasco D B; Casimiro, Teresa; Aguiar-Ricardo, Ana

    2014-07-20

    This work proposes melanin as a new nanocarrier for pH-responsive drug release. Melanin is an abundant natural polymer that can be easily extracted from cuttlefish as nanoparticles with a suitable size range for drug delivery. However, despite its high potentiality, the application of this biopolymer in the pharmaceutical and biomedical fields is yet to be explored. Herein, melanin nanoparticles were impregnated with metronidazole, chosen as model antibiotic drug, using supercritical carbon dioxide. The drug release profile was investigated at acidic and physiologic pH, and the dominant mechanism was found to follow a non-Fickian transport. Drug release from melanin shows a strong pH dependency, which allied to its biocompatibility and lack of cytotoxicity envisages its potential application as nanocarrier in formulations for colon and intestine targeted drug delivery.

  13. Dynamics of Biopolymer Turnover in Soil Physical Fractions Following Land-Cover yChange in a Subtropical Savanna

    NASA Astrophysics Data System (ADS)

    Filley, T. R.; Gamblin, D.; Wang, Y.; Liao, J.; Boutton, T.; Jastrow, J.

    2004-12-01

    Changes in the apportionment of organic carbon and nitrogen among soil physical yfractions following land-cover shifts are of critical importance to the debate surrounding ythe capacity of terrestrial ecosystems to store or release greenhouse gases. For example, ythe difference between the mean residence times (MRTs) of light particulate organic ymatter (POM) vs. silts and clays is typically quite large, with silt and clay associated yorganic matter having the longest MRTs and the greatest likelihood to contribute to long yterm carbon storage. A few studies in agricultural and forest systems have demonstrated ythat biopolymer chemistry also varies along physical, as well as density, fractionation ygradients. We quantified changes in biopolymer (lignin, suberin and cutin, and yhydrolysable amino acids) chemistry of size and density fractionated soil from the Rio yGrande Plains of Texas where C4 grasslands (d13C = -14 %) have undergone succession yto subtropical thorn woodland dominated by C3 trees/shrubs (d13C = -27 %) over the ypast 150 years. This natural isotopic distinction was used to determine MRTs of free ylight organic matter (density less than 1.0 g/cc), macroaggregate (greater than 250 um), ymicroaggregate (53-250 um) and silt+clay (less than 53 um) fractions (see Liao et al., ythis session) which were then related to their specific biopolymer chemistries. Our yresults illustrate that lignin and aliphatic biopolymers (as measured by hydroxyl fatty yacids) are apportioned differently among size/density fractions and along the successional ychronosequence. Lignin is incorporated into all soil fractions soon after woody yencroachment, whereas aliphatic components are slow to be incorporated in the silt and yclay fractions. The lignin components that do become associated with silts and clays are, yin general, highly oxidized. Differences in foliar chemistry among the plant sources yindicate selective movement of leaf cutins into POM, macro- and microaggregate

  14. Abundances in Przybylski's star

    NASA Astrophysics Data System (ADS)

    Cowley, C. R.; Ryabchikova, T.; Kupka, F.; Bord, D. J.; Mathys, G.; Bidelman, W. P.

    2000-09-01

    We have derived abundances for 54 elements in the extreme roAp star HD101065. ESO spectra with a resolution of about 80000, and S/N of 200 or more were employed. The adopted model has Teff=6600K, and log(g)=4.2. Because of the increased line opacity and consequent low gas pressure, convection plays no significant role in the temperature structure. Lighter elemental abundances through the iron group scatter about standard abundance distribution (SAD) (solar) values. Iron and nickel are about one order of magnitude deficient while cobalt is enhanced by 1.5dex. Heavier elements, including the lanthanides, generally follow the solar pattern but enhanced by 3 to 4dex. Odd-Z elements are generally less abundant than their even-Z neighbours. With a few exceptions (e.g. Yb), the abundance pattern among the heavy elements is remarkably coherent, and resembles a displaced solar distribution.

  15. Capella: Structure and Abundances

    NASA Technical Reports Server (NTRS)

    Brickhouse, Nancy S.

    1999-01-01

    This grant covers the analysis of ASCA spectra of the cool star binary system Capella. This project has also required the analysis of simultaneous EUVE data. The ASCA spectrum of Capella could not be fit with standard models; by imposing models based on strong lines observed with EUVE, a problem wavelength region was identified. Correcting the problem required calculations of atomic collision strengths of higher principal quantum number than had ever been calculated, resulting in a paper in process by Liedahl and Brickhouse. With these new models applied to the ASCA spectrum, better fits were obtained. While solar abundance ratios are generally consistent with the ASCA data, the ratio of Ne/Fe is three to four times lower than solar photospheric values. Whether there is a general First Ionization Potential (FIP) effect or a specific neon anomaly cannot be determined from these data. Detailed discussion has been provided to NASA in the most recent annual report (1997). Two poster presentations have been made regarding modeling requirements. A substantial paper is in the final revision form, following review by six co-authors. The results of this work have wide implications, since the newly calculated emission lines almost certainly contribute to other problems in fitting not only other stellar spectra, but also composite supernova remnants, galaxies, and cooling flow clusters of galaxies. Furthermore, Liedahl and Brickhouse have identified other species for which lines of a similar nature (high principal quantum number) will contribute significant flux. For moderate resolution X-ray spectra, lines left out of the models in relatively isolated bands, will be attributed to continuum flux by spectral fitting engines, causing errors in line-to-continuum ratios. Thus addressing the general theoretical problem is of crucial importance.

  16. Hemostatic, antibacterial biopolymers from Acacia arabica (Lam.) Willd. and Moringa oleifera (Lam.) as potential wound dressing materials.

    PubMed

    Bhatnagar, Monica; Parwani, Laxmi; Sharma, Vinay; Ganguli, Jhuma; Bhatnagar, Ashish

    2013-10-01

    Acacia arabica and Moringa oleifera are credited with a number of medicinal properties. Traditionally gum of Acacia plant is used in the treatment of skin disorders to soothe skin rashes, soreness, inflammation and burns while Moringa seed extracts are known to have antibacterial activity. In the present study the potential of the polymeric component of aqueous extracts of gum acacia (GA) and the seeds of M. oleifera (MSP) in wound management was evaluated. The results revealed that both biopolymers were hemostatic and hasten blood coagulation. They showed shortening of activated partial thromboplastin time and prothrombin time and were non-cytotoxic in nature. Both showed antibacterial activity against organisms known to be involved in wound infections with MIC ranging from 500-600 microg mL(-1) for GA and 300-700 microg mL(-1) for MSP. They were biodegradable and exhibited water absorption capacity in the range of 415 to 935%. The hemostatic character coupled to these properties envisions their potential in preparation of dressings for bleeding and profusely exuding wounds. The biopolymers have been further analysed for their composition by Gas chromatography.

  17. Solid-State (13)C NMR Delineates the Architectural Design of Biopolymers in Native and Genetically Altered Tomato Fruit Cuticles.

    PubMed

    Chatterjee, Subhasish; Matas, Antonio J; Isaacson, Tal; Kehlet, Cindie; Rose, Jocelyn K C; Stark, Ruth E

    2016-01-11

    Plant cuticles on outer fruit and leaf surfaces are natural macromolecular composites of waxes and polyesters that ensure mechanical integrity and mitigate environmental challenges. They also provide renewable raw materials for cosmetics, packaging, and coatings. To delineate the structural framework and flexibility underlying the versatile functions of cutin biopolymers associated with polysaccharide-rich cell-wall matrices, solid-state NMR spectra and spin relaxation times were measured in a tomato fruit model system, including different developmental stages and surface phenotypes. The hydrophilic-hydrophobic balance of the cutin ensures compatibility with the underlying polysaccharide cell walls; the hydroxy fatty acid structures of outer epidermal cutin also support deposition of hydrophobic waxes and aromatic moieties while promoting the formation of cell-wall cross-links that rigidify and strengthen the cuticle composite during fruit development. Fruit cutin-deficient tomato mutants with compromised microbial resistance exhibit less efficient local and collective biopolymer motions, stiffening their cuticular surfaces and increasing their susceptibility to fracture.

  18. Xanthan Exopolysaccharide: Cu(2+) Complexes Affected from the pH-Dependent Conformational State; Implications for Environmentally Relevant Biopolymers.

    PubMed

    Causse, Benjamin; Spadini, Lorenzo; Sarret, Géraldine; Faure, Adeline; Travelet, Christophe; Madern, Dominique; Delolme, Cécile

    2016-04-05

    The conformational impact of environmental biopolymers on metal sorption was studied through Cu sorption on xanthan. The apparent Cu(2+) complexation constant (logK; Cu(2+) + L(-) ↔ CuL(+)) decreased from 2.9 ± 0.1 at pH 3.5 to 2.5 ± 0.1 at pH 5.5 (ionic strength I = 0.1). This behavior is in apparent contradiction with basic thermodynamics, as usually the higher the pH the more cations bind. Our combined titration, circular dichroism and dynamic light scattering study indicated that the change observed in Cu bond strength relates to a conformational change of the structure of xanthan, which generates more chelating sites at pH 3.5 than at pH 5.5. This hypothesis was validated by the fact that the Cu sorption constants on xanthan were always higher than those measured on a mixture of pyruvic and glucuronic acids (logK = 2.2), which are the two constitutive ligands present in the xanthan monomer. This study shows the role of the structural conformation of natural biopolymers in metal bond strength. This finding may help to better predict the fate of Cu and other metals in acidic environmental settings such as aquatic media affected by acid mine drainage, as well as peats and acidic soils, and to better define optimal conditions for bioremediation processes.

  19. Relevant insight of surface characterization techniques to study covalent grafting of a biopolymer to titanium implant and its acidic resistance

    NASA Astrophysics Data System (ADS)

    D'Almeida, Mélanie; Amalric, Julien; Brunon, Céline; Grosgogeat, Brigitte; Toury, Bérangère

    2015-02-01

    Peri-implant bacterial infections are the main cause of complications in dentistry. Our group has previously proposed the attachment of chitosan on titanium implants via a covalent bond to improve its antibacterial properties while maintaining its biocompatibility. A better knowledge of the coating preparation process allows a better understanding of the bioactive coating in biological conditions. In this work, several relevant characterization techniques were used to assess an implant device during its production phase and its resistance in natural media at different pH. The titanium surface was functionalized with 3-aminopropyltriethoxysilane (APTES) followed by grafting of an organic coupling agent; succinic anhydride, able to form two covalent links, with the substrate through a Ti-O-Si bond and the biopolymer through a peptide bond. Each step of the coating synthesis as well as the presence confirmation of the biopolymer on titanium after saliva immersion was followed by FTIR-ATR, SEM, EDS, 3D profilometry, XPS and ToF-SIMS analyses. Results allowed to highlight the efficiency of each step of the process, and to propose a mechanism occurring during the chitosan coating degradation in saliva media at pH 5 and at pH 3.

  20. A facile method for processing lignin reinforced chitosan biopolymer microfibres: optimising the fibre mechanical properties through lignin type and concentration

    NASA Astrophysics Data System (ADS)

    Wang, K.; Loo, L. S.; Goh, K. L.

    2016-03-01

    A chitosan biopolymer microfibre—reinforced by lignin—has been processed by a wet-spinning method. To optimise the fibre mechanical and structural properties two types of lignin, with molecular weights 28 000 g mol-1 and 60 000 g mol-1, were examined and the chitosan fibre was blended with the respective lignin type at 1, 3, 5, 7 and 8 wt% lignin concentrations. The main effects of lignin type and concentration, as well as the interaction between the two parameters, on the fibre tensile stiffness, extensibility, strength and toughness were evaluated using the two-factor analysis of variance. Significant variations in the respective mechanical properties were observed with varying lignin concentrations (P < 0.05). The magnitude of the respective mechanical properties is low at 1 wt% but peaks at 3 wt% before decreasing steadily with increasing lignin concentration. Except for extensibility, significant variations in the strength and toughness were observed with respect to lignin type (P < 0.05) variations in the stiffness were masked by interactions between lignin type and concentration. These results were related to the dispersion of lignin in the fibre and the nature of the bonds between lignin and chitosan, based on findings from scanning electron microscopy and Fourier transform infrared spectroscopy. This new method for the fabrication of chitosan biopolymer microfibre is inexpensive and versatile and could lend itself to the production of high performance biocomposite structures.

  1. Functional finishing of aminated polyester using biopolymer-based polyelectrolyte microgels.

    PubMed

    Glampedaki, Pelagia; Dutschk, Victoria; Jocic, Dragan; Warmoeskerken, Marijn M C G

    2011-10-01

    This study focuses on a microgel-based functionalization method applicable to polyester textiles for improving their hydrophilicity and/or moisture-management properties, eventually enhancing wear comfort. The method proposed aims at achieving pH-/temperature-controlled wettability of polyester within a physiological pH/temperature range. First, primary amine groups are created on polyester surfaces using ethylenediamine; second, biopolymer-based polyelectrolyte microgels are incorporated using the natural cross-linker genipin. The microgels consist of the pH-responsive natural polysaccharide chitosan and pH/thermoresponsive poly(N-isopropylacrylamide-co-acrylic acid) microparticles. Scanning electron microscopy confirmed the microgel presence on polyester surfaces. X-ray photoelectron spectroscopy revealed nitrogen concentration, supporting increased microscopy results. Electrokinetic analysis showed that functionalized polyester surfaces have a zero-charge point at pH 6.5, close to the microgel isoelectric point. Dynamic wetting measurements revealed that functionalized polyester has shorter total water absorption time than the reference. This absorption time is also pH dependent, based on dynamic contact angle and micro-roughness measurements, which indicated microgel swelling at different pH values. Furthermore, at 40 °C functionalized polyester has higher vapor transmission rates than the reference, even at high relative humidity. This was attributed to the microgel thermoresponsiveness, which was confirmed through the almost 50% decrease in microparticle size between 20 and 40 °C, as determined by dynamic light scattering measurements.

  2. Recovery of oil from oil-in-water emulsion using biopolymers by adsorptive method.

    PubMed

    Elanchezhiyan, S Sd; Sivasurian, N; Meenakshi, Sankaran

    2014-09-01

    In the present study, it is aimed to identify, a low cost sorbent for the recovery of oil from oil-in-water emulsion using biopolymers such as chitin and chitosan. Chitin has the greater adsorption capacity than chitosan due to its hydrophobic nature. The characterizations of chitin and chitosan were done using FTIR, SEM, EDAX, XRD, TGA and DSC techniques. Under batch equilibrium mode, a systematic study was performed to optimize the various equilibrium parameters viz., contact time, pH, dosage, initial concentration of oil, and temperature. The adsorption process reached equilibrium at 40 min of contact time and the percentage removal of oil was found to be higher (90%) in the acidic medium. The Freundlich and Langmuir models were applied to describe the equilibrium isotherms and the isotherm constants were calculated. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated to find out the nature of the sorption mechanism. The kinetic studies were investigated with reaction-based and diffusion-based models. The suitable mechanism for the removal of oil has been established.

  3. Natural biopolimers in organic food packaging

    NASA Astrophysics Data System (ADS)

    Wieczynska, Justyna; Cavoski, Ivana; Chami, Ziad Al; Mondelli, Donato; Di Donato, Paola; Di Terlizzi, Biagio

    2014-05-01

    Concerns on environmental and waste problems caused by use of non-biodegradable and non-renewable based plastic packaging have caused an increase interest in developing biodegradable packaging using renewable natural biopolymers. Recently, different types of biopolymers like starch, cellulose, chitosan, casein, whey protein, collagen, egg white, soybean protein, corn zein, gelatin and wheat gluten have attracted considerable attention as potential food packaging materials. Recyclable or biodegradable packaging material in organic processing standards is preferable where possible but specific principles of packaging are not precisely defined and standards have to be assessed. There is evidence that consumers of organic products have specific expectations not only with respect to quality characteristics of processed food but also in social and environmental aspects of food production. Growing consumer sophistication is leading to a proliferation in food eco-label like carbon footprint. Biopolymers based packaging for organic products can help to create a green industry. Moreover, biopolymers can be appropriate materials for the development of an active surfaces designed to deliver incorporated natural antimicrobials into environment surrounding packaged food. Active packaging is an innovative mode of packaging in which the product and the environment interact to prolong shelf life or enhance safety or sensory properties, while maintaining the quality of the product. The work will discuss the various techniques that have been used for development of an active antimicrobial biodegradable packaging materials focusing on a recent findings in research studies. With the current focus on exploring a new generation of biopolymer-based food packaging materials with possible applications in organic food packaging. Keywords: organic food, active packaging, biopolymers , green technology

  4. Detecting the Biopolymer Behavior of Graphene Nanoribbons in Aqueous Solution

    PubMed Central

    Wijeratne, Sithara S.; Penev, Evgeni S.; Lu, Wei; Li, Jingqiang; Duque, Amanda L.; Yakobson, Boris I.; Tour, James M.; Kiang, Ching-Hwa

    2016-01-01

    Graphene nanoribbons (GNR), can be prepared in bulk quantities for large-area applications by reducing the product from the lengthwise oxidative unzipping of multiwalled carbon nanotubes (MWNT). Recently, the biomaterials application of GNR has been explored, for example, in the pore to be used for DNA sequencing. Therefore, understanding the polymer behavior of GNR in solution is essential in predicting GNR interaction with biomaterials. Here, we report experimental studies of the solution-based mechanical properties of GNR and their parent products, graphene oxide nanoribbons (GONR). We used atomic force microscopy (AFM) to study their mechanical properties in solution and showed that GNR and GONR have similar force-extension behavior as in biopolymers such as proteins and DNA. The rigidity increases with reducing chemical functionalities. The similarities in rigidity and tunability between nanoribbons and biomolecules might enable the design and fabrication of GNR-biomimetic interfaces. PMID:27503635

  5. Detecting the Biopolymer Behavior of Graphene Nanoribbons in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Wijeratne, Sithara S.; Penev, Evgeni S.; Lu, Wei; Li, Jingqiang; Duque, Amanda L.; Yakobson, Boris I.; Tour, James M.; Kiang, Ching-Hwa

    2016-08-01

    Graphene nanoribbons (GNR), can be prepared in bulk quantities for large-area applications by reducing the product from the lengthwise oxidative unzipping of multiwalled carbon nanotubes (MWNT). Recently, the biomaterials application of GNR has been explored, for example, in the pore to be used for DNA sequencing. Therefore, understanding the polymer behavior of GNR in solution is essential in predicting GNR interaction with biomaterials. Here, we report experimental studies of the solution-based mechanical properties of GNR and their parent products, graphene oxide nanoribbons (GONR). We used atomic force microscopy (AFM) to study their mechanical properties in solution and showed that GNR and GONR have similar force-extension behavior as in biopolymers such as proteins and DNA. The rigidity increases with reducing chemical functionalities. The similarities in rigidity and tunability between nanoribbons and biomolecules might enable the design and fabrication of GNR-biomimetic interfaces.

  6. Classic Analysis of Biopolymer Dynamics Is Model Free.

    PubMed

    Fenwick, R Bryn; Dyson, H Jane

    2016-01-05

    Early analysis of biopolymer dynamics relied on a variety of motional models that were difficult to distinguish and sometimes gave contradictory results. The Lipari-Szabo model-free approach (documented in a 1980 article in Biophysical Journal, as well as in two more comprehensive 1982 articles in the Journal of the American Chemical Society, provided a simple formalism that allowed investigators to understand fluorescence and NMR experimental data without having to specify a motional model. Although the model-free method is not universally applicable (for example, its assumption of a uniform correlation time for overall molecular tumbling can be problematic for biomolecules containing areas of disorder), it remains the most popular and widely used technique for analyzing molecular motion.

  7. Topologically ordered magnesium-biopolymer hybrid composite structures.

    PubMed

    Oosterbeek, Reece N; Seal, Christopher K; Staiger, Mark P; Hyland, Margaret M

    2015-01-01

    Magnesium and its alloys are intriguing as possible biodegradable biomaterials due to their unique combination of biodegradability and high specific mechanical properties. However, uncontrolled biodegradation of magnesium during implantation remains a major challenge in spite of the use of alloying and protective coatings. In this study, a hybrid composite structure of magnesium metal and a biopolymer was fabricated as an alternative approach to control the corrosion rate of magnesium. A multistep process that combines metal foam production and injection molding was developed to create a hybrid composite structure that is topologically ordered in all three dimensions. Preliminary investigations of the mechanical properties and corrosion behavior exhibited by the hybrid Mg-polymer composite structures suggest a new potential approach to the development of Mg-based biomedical devices.

  8. The Rheological Properties of the Biopolymers in Synovial Fluid

    NASA Astrophysics Data System (ADS)

    Krause, Wendy E.; Klossner, Rebecca R.; Wetsch, Julie; Oates, Katherine M. N.; Colby, Ralph H.

    2005-03-01

    The polyelectrolyte hyaluronic acid (HA, hyaluronan), its interactions with anti-inflammatory drugs and other biopolymers, and its role in synovial fluid are being studied. We are investigating the rheological properties of sodium hyaluronate (NaHA) solutions and an experimental model of synovial fluid (comprised of NaHA, and the plasma proteins albumin and γ-globulins). Steady shear measurements on bovine synovial fluid and the synovial fluid model indicate that the fluids are highly viscoeleastic and rheopectic (stress increases with time under steady shear). In addition, the influence of anti-inflammatory agents on these solutions is being explored. Initial results indicate that D-penicillamine and hydroxychloroquine affect the rheology of the synovial fluid model and its components. The potential implications of these results will be discussed.

  9. Gel Point Determination of Biopolymer Based Semi-IPN Hydrogels

    NASA Astrophysics Data System (ADS)

    Choudhary, Soumitra; Bhatia, Surita R.

    2008-07-01

    Water-based semi-IPNs (Interpenetrating Polymer Networks) were prepared by mixing two biopolymers, alginate and hydrophobically modified ethylhydroxy ethyl cellulose (HMEHEC), followed by crosslinking the alginate by in-situ release of calcium ions. By altering two different parameters, molecular weight of HMEHEC and calcium crosslinker concentration, we were able to fine tune the rheological properties of the semi-IPNs. Rheological studies in the linear viscoelastic region indicate storage moduli comparable to soft tissue for hydrogels having 90 wt% water. The system is found to be stable over a prolonged period of time, i.e. no phase separation is observed. Uniformity of the structure is confirmed by monotonic behavior of the intensity-q slope in SAXS and SANS over the entire length scale.

  10. Conjugates of a photoactivated rhodamine with biopolymers for cell staining.

    PubMed

    Zaitsev, Sergei Yu; Shaposhnikov, Mikhail N; Solovyeva, Daria O; Solovyeva, Valeria V; Rizvanov, Albert A

    2014-01-01

    Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids) are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD) has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan ("Chitosan-PFD") and histone H1 ("Histone H1.3-PFD"). The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK). Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes ("caged" dyes) for microscopic probing of biological objects. Thus, the synthesized "Chitosan-PFD" and "Histone H1-PFD" have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy.

  11. [Binding of Volatile Organic Compounds to Edible Biopolymers].

    PubMed

    Misharina, T A; Terenina, M B; Krikunova, N I; Medvedeva, I B

    2016-01-01

    Capillary gas chromatography was used to study the influence of the composition and structure of different edible polymers (polysaccharides, vegetable fibers, and animal protein gelatin) on the binding of essential oil components. The retention of volatile organic compounds on biopolymers was shown to depend on their molecule structure and the presence, type, and position of a functional group. The maximum extent of the binding was observed for nonpolar terpene and sesquiterpene hydrocarbons, and the minimum extent was observed for alcohols. The components of essential oils were adsorbed due mostly to hydrophobic interactions. It was shown that the composition and structure of a compound, its physico-chemical state, and the presence of functional groups influence the binding. Gum arabic and guar gum were found to bind nonpolar compounds to a maximum and minimum extent, respectively. It was demonstrated the minimum adsorption ability of locust bean gum with respect to all studied compounds.

  12. LassoProt: server to analyze biopolymers with lassos

    PubMed Central

    Dabrowski-Tumanski, Pawel; Niemyska, Wanda; Pasznik, Pawel; Sulkowska, Joanna I.

    2016-01-01

    The LassoProt server, http://lassoprot.cent.uw.edu.pl/, enables analysis of biopolymers with entangled configurations called lassos. The server offers various ways of visualizing lasso configurations, as well as their time trajectories, with all the results and plots downloadable. Broad spectrum of applications makes LassoProt a useful tool for biologists, biophysicists, chemists, polymer physicists and mathematicians. The server and our methods have been validated on the whole PDB, and the results constitute the database of proteins with complex lassos, supported with basic biological data. This database can serve as a source of information about protein geometry and entanglement-function correlations, as a reference set in protein modeling, and for many other purposes. PMID:27131383

  13. LassoProt: server to analyze biopolymers with lassos.

    PubMed

    Dabrowski-Tumanski, Pawel; Niemyska, Wanda; Pasznik, Pawel; Sulkowska, Joanna I

    2016-07-08

    The LassoProt server, http://lassoprot.cent.uw.edu.pl/, enables analysis of biopolymers with entangled configurations called lassos. The server offers various ways of visualizing lasso configurations, as well as their time trajectories, with all the results and plots downloadable. Broad spectrum of applications makes LassoProt a useful tool for biologists, biophysicists, chemists, polymer physicists and mathematicians. The server and our methods have been validated on the whole PDB, and the results constitute the database of proteins with complex lassos, supported with basic biological data. This database can serve as a source of information about protein geometry and entanglement-function correlations, as a reference set in protein modeling, and for many other purposes.

  14. Evolutionary optimization of biopolymers and sequence structure maps

    SciTech Connect

    Reidys, C.M.; Kopp, S.; Schuster, P.

    1996-06-01

    Searching for biopolymers having a predefined function is a core problem of biotechnology, biochemistry and pharmacy. On the level of RNA sequences and their corresponding secondary structures we show that this problem can be analyzed mathematically. The strategy will be to study the properties of the RNA sequence to secondary structure mapping that is essential for the understanding of the search process. We show that to each secondary structure s there exists a neutral network consisting of all sequences folding into s. This network can be modeled as a random graph and has the following generic properties: it is dense and has a giant component within the graph of compatible sequences. The neutral network percolates sequence space and any two neutral nets come close in terms of Hamming distance. We investigate the distribution of the orders of neutral nets and show that above a certain threshold the topology of neutral nets allows to find practically all frequent secondary structures.

  15. Interpretation of fluorescence correlation spectra of biopolymer solutions.

    PubMed

    Phillies, George D J

    2016-05-01

    Fluorescence correlation spectroscopy (FCS) is regularly used to study diffusion in non-dilute "crowded" biopolymer solutions, including the interior of living cells. For fluorophores in dilute solution, the relationship between the FCS spectrum G(t) and the diffusion coefficient D is well-established. However, the dilute-solution relationship between G(t) and D has sometimes been used to interpret FCS spectra of fluorophores in non-dilute solutions. Unfortunately, the relationship used to interpret FCS spectra in dilute solutions relies on an assumption that is not always correct in non-dilute solutions. This paper obtains the correct form for interpreting FCS spectra of non-dilute solutions, writing G(t) in terms of the statistical properties of the fluorophore motions. Approaches for applying this form are discussed.

  16. Biopolymers Confined in Surface-Modified Silicon Microfluidic Channels

    NASA Astrophysics Data System (ADS)

    Li, Y.; Pfohl, T.; Yasa, M.; Safinya, C. R.; Kim, J. H.; Kim, M. W.; Wen, Z.

    2001-03-01

    We have developed surface modification techniques for control of wettability and surface charge in lithographically fabricated Si microfluidic channels. Surface microstructures (patterns) with contrasting wetting properties were created using a combination of microcontact printing and polyelectrolyte adsorption. The selective control of the surface property enabled us to devise various techniques for loading and processing biomaterials in the channels. Using fluorescence and laser scanning confocal microscopy, we studied the structure of biopolymers including DNA, F-Actin and microtubules confined in the surface-modified microchannels. The polymers were observed to align linearly along the channels, which suggests that the channel arrays can be used as effective substrates for aligning filamentous proteins for structural characterization by x-ray diffraction. (Work supported by NSF-DMR-9972246, NSF-DMR-0076357, ONR-N00014-00-1-0214, UC-Biotech 99-14, and CULAR 99-216)

  17. Highly Sensitive and Selective Uranium Detection in Natural Water Systems Using a Luminescent Mesoporous Metal-Organic Framework Equipped with Abundant Lewis Basic Sites: A Combined Batch, X-ray Absorption Spectroscopy, and First Principles Simulation Investigation.

    PubMed

    Liu, Wei; Dai, Xing; Bai, Zhuanling; Wang, Yanlong; Yang, Zaixing; Zhang, Linjuan; Xu, Lin; Chen, Lanhua; Li, Yuxiang; Gui, Daxiang; Diwu, Juan; Wang, Jianqiang; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

    2017-04-04

    Uranium is not only a strategic resource for the nuclear industry but also a global contaminant with high toxicity. Although several strategies have been established for detecting uranyl ions in water, searching for new uranium sensor material with great sensitivity, selectivity, and stability remains a challenge. We introduce here a hydrolytically stable mesoporous terbium(III)-based MOF material compound 1, whose channels are as large as 27 Å × 23 Å and are equipped with abundant exposed Lewis basic sites, the luminescence intensity of which can be efficiently and selectively quenched by uranyl ions. The detection limit in deionized water reaches 0.9 μg/L, far below the maximum contamination standard of 30 μg/L in drinking water defined by the United States Environmental Protection Agency, making compound 1 currently the only MOF material that can achieve this goal. More importantly, this material exhibits great capability in detecting uranyl ions in natural water systems such as lake water and seawater with pH being adjusted to 4, where huge excesses of competing ions are present. The uranyl detection limits in Dushu Lake water and in seawater were calculated to be 14.0 and 3.5 μg/L, respectively. This great detection capability originates from the selective binding of uranyl ions onto the Lewis basic sites of the MOF material, as demonstrated by synchrotron radiation extended X-ray adsorption fine structure, X-ray adsorption near edge structure, and first principles calculations, further leading to an effective energy transfer between the uranyl ions and the MOF skeleton.

  18. Microbial Flocculant for Nature Soda

    SciTech Connect

    Qin, Peiyong; Zhang, Tong; Chen, Cuixian

    2004-03-31

    Microbial flocculant for nature soda has been studied. Lactobacillus TRJ21, which was able to produce an excellent biopolymer flocculant for nature soda, was obtained in our lab. The microbial flocculant was mainly produced when the bacteria laid in stationary growth phase. Fructose or glucose, as carbon sources, were more favorable for the bacterial growth and flocculant production. The bacteria was able to use ammonium sulfate or Urea as nitrogen to produce flocculant, but was not able to use peptone effectively. High C/N ratio was more favorable to Lactobacillus TRJ21 growth and flocculant production than low C/N ratio. The biopolymer flocculant was mainly composed of polysaccharide and protein with a molecular weight 1.38x106 by gel permeation chromatography. It was able to be easily purified from the culture medium by acetone. Protein in the flocculant was tested for the flocculating activity ingredient by heating the flocculant.

  19. OXYGEN ABUNDANCES IN CEPHEIDS

    SciTech Connect

    Luck, R. E.; Andrievsky, S. M.; Korotin, S. N.; Kovtyukh, V. V. E-mail: serkor@skyline.od.ua E-mail: scan@deneb1.odessa.ua

    2013-07-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  20. The effect of ultrasonication on calcium carbonate crystallization in the presence of biopolymer

    NASA Astrophysics Data System (ADS)

    Kirboga, Semra; Oner, Mualla; Akyol, Emel

    2014-09-01

    Synthesis of calcium carbonate (CaCO3) was carried out using sonication in aqueous solution medium. The effect of the probe immersion depth (PID) and the amplitude of sonicator on calcium carbonate crystallization were studied in the absence and presence of biopolymer, carboxymethyl inulin (CMI). Calcium carbonate crystals synthesized with and without ultrasound were compared. X-ray diffraction (XRD) analysis showed that calcium carbonate obtained in the presence of biopolymer was a mixture of calcite and vaterite whereas there was only calcite polymorph in the absence of biopolymer. In the presence of biopolymer, the relative fraction of vaterite increased with the application of sonication process. The higher amplitude resulted in the higher relative vaterite fraction. The results showed that the probe immersion depth and the amplitude affected the morphology of calcium carbonate.

  1. Photoluminescence intensity enhancement in SWNT aqueous suspensions due to reducing agent doping: Influence of adsorbed biopolymer

    NASA Astrophysics Data System (ADS)

    Kurnosov, N. V.; Leontiev, V. S.; Linnik, A. S.; Lytvyn, O. S.; Karachevtsev, V. A.

    2014-06-01

    The influence of biopolymer wrapped around nanotube on the enhancement of the semiconducting single-walled carbon nanotube (SWNT) photoluminescence (PL) in aqueous suspension which increases due to the reducing agent dithiothreitol (DTT) doping effect was revealed. The greatest enhancement of PL was observed for SWNTs covered with double- or single stranded DNA (above 170%) and DTT weak influence was revealed for SWNTs:polyC suspension (∼45%). The magnitude of the PL enhancement depends also on nanotube chirality and sample aging. The behavior of PL from SWNTs covered with various polymers is explained by the different biopolymers ordering on the nanotube surface. The ordered polymer conformation on the nanotube weakens the reducing agent doping effect. The method of reducing agent doping of nanotube:biopolymer aqueous suspension can serve as a sensitive luminescent probe of the biopolymer ordering on the carbon nanotube and can be used to increase the sensitivity of luminescent biosensors.

  2. Anaerobic digestion of starch-polyvinyl alcohol biopolymer packaging: biodegradability and environmental impact assessment.

    PubMed

    Guo, M; Trzcinski, A P; Stuckey, D C; Murphy, R J

    2011-12-01

    The digestibility of a starch-polyvinyl alcohol (PVOH) biopolymer insulated cardboard coolbox was investigated under a defined anaerobic digestion (AD) system with key parameters characterized. Laboratory results were combined with industrial operational data to develop a site-specific life cycle assessment (LCA) model. Inoculated with active bacterial trophic groups, the anaerobic biodegradability of three starch-PVOH biopolymers achieved 58-62%. The LCA modeling showed that the environmental burdens of the starch-PVOH biopolymer packaging under AD conditions on acidification, eutrophication, global warming and photochemical oxidation potential were dominated by atmospheric emissions released from substrate degradation and fuel combustion, whereas energy consumption and infrastructure requirements were the causes of abiotic depletion, ozone depletion and toxic impacts. Nevertheless, for this bio-packaging, AD of the starch-PVOH biopolymer combined with recycling of the cardboard emerged as the environmentally superior option and optimization of the energy utilization system could bring further environmental benefits to the AD process.

  3. Binary and Ternary Mixtures of Biopolymers and Water: Viscosity, Refractive Index, and Density

    NASA Astrophysics Data System (ADS)

    Silva, Bárbara Louise L. D.; Costa, Bernardo S.; Garcia-Rojas, Edwin E.

    2016-08-01

    Biopolymers have been the focus of intense research because of their wide applicability. The thermophysical properties of solutions containing biopolymers have fundamental importance for engineering calculations, as well as for thermal load calculations, energy expenditure, and development of new products. In this work, the thermophysical properties of binary and ternary solutions of carboxymethylcellulose and/or high methoxylation pectin and water at different temperatures have been investigated taking into consideration different biopolymer concentrations. The experimental data related to the thermophysical properties were correlated to obtain empirical models that can describe the temperature-concentration combined effect on the density, refractive index, and dynamic viscosity. From data obtained from the experiments, the density, refractive index, and dynamic viscosity increase with increasing biopolymer concentration and decrease with increasing temperature. The polynomial models showed a good fit to the experimental data and high correlation coefficients (R2ge 0.98) for each studied system.

  4. Single walled carbon nanotubes functionally adsorbed to biopolymers for use as chemical sensors

    DOEpatents

    Johnson, Jr., Alan T.; Gelperin, Alan; Staii, Cristian

    2011-07-12

    Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

  5. Photoacoustic monitoring of water transport process in calcareous stone coated with biopolymers

    NASA Astrophysics Data System (ADS)

    May-Crespo, J.; Ortega-Morales, B. O.; Camacho-Chab, J. C.; Quintana, P.; Alvarado-Gil, J. J.; Gonzalez-García, G.; Reyes-Estebanez, M.; Chan-Bacab, M. J.

    2016-12-01

    Moisture is a critical control of chemical and physical processes leading to stone deterioration. These processes can be enhanced by microbial biofilms and associated exopolymers (EPS). There is limited current understanding of the water transport process across rocks covered by EPS. In the present work, we employed the photoacoustic technique to study the influence of three biopolymers (xanthan, microbactan and arabic gum) in the water transport process of two types of limestone rock of similar mineralogy but contrasting porosity. Both controls of RL (low porosity) and RP (high porosity) presented the higher values of water diffusion coefficient ( D) than biopolymer-coated samples, indicating that biopolymer layers slowed down the transport of water. This trend was steeper for RP samples as water was transported seven times faster than in the more porous rock. Important differences of D values were observed among samples coated by different biopolymers. Scanning electron microscopy and optical microscopy showed that surface topography was different between both types of rocks; adherence of coatings was seen predominantly in the less porous rocks samples. FTIR and NMR analysis showed the presence of pyruvate and acetate in microbactan and xanthan gum, suggesting their participation on adherence to the calcareous surfaces, sealing surface pores. These results indicate that water transport at rock interfaces is dependent on the chemistry of biopolymer and surface porosity. The implications for reduced water transport in stone conservation under the influence of biopolymers include both enhanced and lower deterioration rates along with altered efficiency of biocide treatment of epilithic biofilms.

  6. Infrared spectroscopic study of thermotropic phase behavior of newly developed synthetic biopolymers.

    PubMed

    Bista, Rajan K; Bruch, Reinhard F; Covington, Aaron M

    2011-10-15

    The thermotropic phase behavior of a suite of newly developed self-forming synthetic biopolymers has been investigated by variable-temperature Fourier transform infrared (FT-IR) absorption spectroscopy. The temperature-induced infrared spectra of these artificial biopolymers (lipids) composed of 1,2-dimyristoyl-rac-glycerol-3-dodecaethylene glycol (GDM-12), 1,2-dioleoyl-rac-glycerol-3-dodecaethylene glycol (GDO-12) and 1,2-distearoyl-rac-glycerol-3-triicosaethylene glycol (GDS-23) in the spectral range of 4000-500 cm(-1) have been acquired by using a thin layered FT-IR spectrometer in conjunction with a custom built temperature-controlled demountable liquid cell having a pathlength of ∼15 μm. The lipids under consideration have long hydrophobic acyl chains and contain various units of hydrophilic polyethylene glycol (PEG) headgroups. In contrast to conventional phospholipids, this new kind of lipids forms liposomes or nanovesicles spontaneously upon hydration, without requiring external activation energy. We have found that the thermal stability of the PEGylated lipids differs greatly depending upon the acyl chain-lengths as well as the nature of the associated bonds and the number of PEG headgroup units. In particular, GDM-12 (saturated 14 hydrocarbon chains with 12 units of PEG headgroup) exhibits one sharp order-disorder phase transition over a temperature range increasing from 3°C to 5°C. Similarly, GDS-23 (saturated 18 hydrocarbon chains with 23 units of PEG headgroup) displays comparatively broad order-disorder phase transition profiles between temperature 17°C and 22°C. In contrast, GDO-12 (monounsaturated 18 hydrocarbon chains with 12 units of PEG headgroup) does not reveal any order-disorder transition phenomena demonstrating a highly disordered behavior for the entire temperature range. To confirm these observations, differential scanning calorimetry (DSC) was applied to the samples and revealed good agreement with the infrared spectroscopy results

  7. Adsorption studies of Cu(II) onto biopolymer chitosan and its nanocomposite 5%bentonite/chitosan.

    PubMed

    Moussout, Hamou; Ahlafi, Hammou; Aazza, Mustapha; Zegaoui, Omar; El Akili, Charaf

    2016-01-01

    Chitosan (CS) and nanocomposite 5%bentonite/chitosan (5%Bt/CS) prepared from the natural biopolymer CS were tested to remove Cu(II) ions using a batch adsorption experiment at various temperatures (25, 35 and 45°C). X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis (TGA/DTA) were used in CS and the nanocomposite characterisation. This confirmed the exfoliation of bentonite (Bt) to form the nanocomposite. The adsorption kinetics of copper on both solids was found to follow a pseudo-second-order law at each studied temperature. The Cu(II) adsorption capacity increased as the temperature increased from 25 to 45°C for nanocomposite adsorbent but slightly increased for CS. The data were confronted to the nonlinear Langmuir, Freundlich and Redlich-Peterson models. It was found that the experimental data fitted very well the Langmuir isotherm over the whole temperature and concentration ranges. The maximum monolayer adsorption capacity for the Cu(II) was 404-422 mg/g for CS and 282-337 mg/g for 5%Bt/CS at 25-45°C. The thermodynamic study showed that the adsorption process was spontaneous and endothermic. The complexation of Cu(II) with NH(2) and C = O groups as active sites was found to be the main mechanism in the adsorption processes.

  8. Not any new functional polymer can be for medicine: what about artificial biopolymers?

    PubMed

    Vert, Michel

    2011-12-08

    Man-made artificial organic polymers are among the more recent sources of materials used by humans. In medicine, they contribute to applications in surgery, dentistry and pharmacology. Nowadays, innovations in the field of therapeutic polymers rely on novel polymers for specific applications such as guided tissue regeneration, tissue engineering, drug delivery systems, gene transfection, etc. Introducing reactive chemical functions within or along polymer backbones is an attractive route to generate functional polymers for medicine. However, any candidate to effective application must fulfil a number of requirements, grouped under the terms biocompatibility and biofunctionality, to be of real interest and have a future for effective application. Whenever the application requires a therapeutic aid for a limited period of time to help natural healing, bioresorbability is to be taken into account on top of biocompatibility and biofunctionality. This contribution presents the case of "artificial biopolymers" and discusses the potential of some members of the family with respect to temporary therapeutic applications that require functional polymers.

  9. Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization

    PubMed Central

    Jóźwiak, Bertrand; Orczykowska, Magdalena; Dziubiński, Marek

    2015-01-01

    The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G’ and G” and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process. PMID:26599756

  10. Tailored topography control of biopolymer surfaces by ultrafast lasers for cell-substrate studies

    NASA Astrophysics Data System (ADS)

    Rusen, L.; Cazan, M.; Mustaciosu, C.; Filipescu, M.; Sandel, S.; Zamfirescu, M.; Dinca, V.; Dinescu, M.

    2014-05-01

    Nowadays, the culture surfaces used for in vitro testing must be capable of possessing an improved interface for cell interactions and adhesion. For this reason, the materials used need to have an appropriate chemistry and architecture of its surface, resembling to the extracellular matrix. Within this context, in this work we combined the advantages of natural biopolymer characteristics (chitosan) with the flexibility in surface texturing by ultrafast laser for creating functional microstructured surfaces for cell-substrate in vitro studies. A Ti:Sapphire femtosecond laser irradiation (λ = 775 nm and 387 nm) was used for tailoring surface morphological characteristics of chitosan based films (i.e. polymer “bubbles”, “fingertips” and “sponge-like” structures). These structures were investigated by scanning electron microscopy and atomic force microscopy. The morphology of the structures obtained was correlated with the response of oligodendrocytes cells line. In vitro tests on the patterned surface showed that early cell growth was conditioned by the microtopography and indicate possible uses of the structures in biomedical applications.

  11. Impact of Molecular Weight on Lymphatic Drainage of a Biopolymer-Based Imaging Agent

    PubMed Central

    Bagby, Taryn R.; Cai, Shuang; Duan, Shaofeng; Thati, Sharadvi; Aires, Daniel J.; Forrest, Laird

    2012-01-01

    New lymphatic imaging technologies are needed to better assess immune function and cancer progression and treatment. Lymphatic uptake depends mainly on particle size (10–100 nm) and charge. The size of carriers for imaging and drug delivery can be optimized to maximize lymphatic uptake, localize chemotherapy to lymphatic metastases, and enable visualization of treatment deposition. Toward this end, female BALB/c mice were injected subcutaneously in the hind footpad or forearm with a series of six different molecular weight hyaluronan (HA) near-infrared dye (HA-IR820) conjugates (ca. 5–200 nm). Mice were imaged using whole body fluorescent imaging over two weeks. HA-IR820 fluorescence was clearly visualized in the draining lymphatic capillaries, and in the popliteal and iliac or axillary lymph nodes. The 74-kDa HA-IR820 had the largest lymph node area-under-the-curve. In contrast to prior reports, mice bearing limb tumors exhibited three-fold longer retention of 74-kDa HA-IR820 in the popliteal node compared to mice without tumors. HA conjugate kinetics and disposition can be specifically tailored by altering their molecular weight. The specific lymphatic uptake and increased nodal retention of HA conjugates indicate significant potential for development as a natural biopolymer for intralymphatic drug delivery and imaging. PMID:24300232

  12. Abundance estimation and conservation biology

    USGS Publications Warehouse

    Nichols, J.D.; MacKenzie, D.I.

    2004-01-01

    Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001). The initial capture–recapture models developed for partially (Darroch, 1959) and completely (Jolly, 1965; Seber, 1965) open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992), and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993). However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001). The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004) is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004) emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004) also suggest that our attention

  13. Evaluation of Rhizobium tropici-derived Biopolymer for Erosion Control of Protective Berms. Field Study: Iowa Army Ammunition Plant

    DTIC Science & Technology

    2016-06-01

    biopolymer outperformed the commercial petroleum-based polymers in all applications . ERDC TR-16-5 5 Figure 1-2. Comparison of the production of...manufacturer estimates of application times, the treatment was successful. Biologically produced polymers have a number of unique benefits when compared...biopolymer with grass seed. The control area received plain water and seed. Evaluated biopolymer application methods include single surface application

  14. Fabrication, functionalization, and application of electrospun biopolymer nanofibers.

    PubMed

    Kriegel, Christina; Arecchi, Alessandra; Arrechi, Alessandra; Kit, Kevin; McClements, D J; Weiss, Jochen

    2008-09-01

    -fiber manufacturing with a particular emphasis on the use of biopolymers. We will review typical fabrication set-ups, discuss the influence of process conditions on nanofiber properties, and then review previous studies that describe the production of biopolymer-based nanofibers. Finally we briefly discuss emerging methods to further functionalize fibers and discuss potential applications in the area of food science and technology.

  15. Dispersion of cellulose nanofibers in biopolymer based nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Bei

    The focus of this work was to understand the fundamental dispersion mechanism of cellulose based nanofibers in bionanocomposites. The cellulose nanofibers were extracted from soybean pod and hemp fibers by chemo-mechanical treatments. These are bundles of cellulose nanofibers with a diameter ranging between 50 to 100 nm and lengths of thousands of nanometers which results in very high aspect ratio. In combination with a suitable matrix polymer, cellulose nanofiber networks show considerable potential as an effective reinforcement for high quality specialty applications of bio-based nanocomposites. Cellulose fibrils have a high density of --OH groups on the surface, which have a tendency to form hydrogen bonds with adjacent fibrils, reducing interaction with the surrounding matrix. The use of nanofibers has been mostly restricted to water soluble polymers. This thesis is focused on synthesizing the nanocomposite using a solid phase matrix polypropylene (PP) or polyethylene (PE) by hot compression and poly (vinyl alcohol) (PVA) in an aqueous phase by film casting. The mechanical properties of nanofiber reinforced PVA film demonstrated a 4-5 fold increase in tensile strength, as compared to the untreated fiber-blend-PVA film. It is necessary to reduce the entanglement of the fibrils and improve their dispersion in the matrix by surface modification of fibers without deteriorating their reinforcing capability. Inverse gas chromatography (IGC) was used to explore how various surface treatments would change the dispersion component of surface energy and acid-base character of cellulose nanofibers and the effect of the incorporation of these modified nanofibers into a biopolymer matrix on the properties of their nano-composites. Poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based nanocomposites using cellulose nanofibers were prepared by extrusion, injection molding and hot compression. The IGC results indicated that styrene maleic anhydride coated and ethylene

  16. Recent Advances in Electromechanical Imaging on the Nanometer Scale: Polarization Dynamics in Ferroelectrics, Biopolymers, and Liquid Imaging

    NASA Astrophysics Data System (ADS)

    Kalinin, Sergei V.; Jesse, Stephen; Rodriguez, Brian J.; Seal, Katyayani; Baddorf, Arthur P.; Zhao, Tong; Chu, Y. H.; Ramesh, Ramamoorthy; Eliseev, Eugene A.; Morozovska, Anna N.; Mirman, B.; Karapetian, Edgar

    2007-09-01

    Coupling between electrical and mechanical phenomena is ubiquitous in nature, with examples ranging from piezoelectricity in polar perovskites and chemical bonds to complex pathways of electromechanical transformations underpinning the functionality of electromotor proteins, cells, and tissues. Piezoresponse force microscopy (PFM) had originally emerged as a technique to study electromechanical phenomena in ferroelectric perovskites on the nanoscale. In recent years, the applicability of PFM for studying a broad range of non-ferroelectric polar materials has been demonstrated, necessitating further development of the technique, including theory of the image formation mechanism as well as probe and controller development. Here, we review the basic principles of PFM and summarize some of the recent advances, including switching spectroscopy, mapping of polarization dynamics in ferroelectric and multiferroic nanostructures, imaging of biopolymers in calcified and connective tissues and PFM in liquid environments.

  17. Economic assessment of flash co-pyrolysis of short rotation coppice and biopolymer waste streams.

    PubMed

    Kuppens, T; Cornelissen, T; Carleer, R; Yperman, J; Schreurs, S; Jans, M; Thewys, T

    2010-12-01

    The disposal problem associated with phytoextraction of farmland polluted with heavy metals by means of willow requires a biomass conversion technique which meets both ecological and economical needs. Combustion and gasification of willow require special and costly flue gas treatment to avoid re-emission of the metals in the atmosphere, whereas flash pyrolysis mainly results in the production of (almost) metal free bio-oil with a relatively high water content. Flash co-pyrolysis of biomass and waste of biopolymers synergistically improves the characteristics of the pyrolysis process: e.g. reduction of the water content of the bio-oil, more bio-oil and less char production and an increase of the HHV of the oil. This research paper investigates the economic consequences of the synergistic effects of flash co-pyrolysis of 1:1 w/w ratio blends of willow and different biopolymer waste streams via cost-benefit analysis and Monte Carlo simulations taking into account uncertainties. In all cases economic opportunities of flash co-pyrolysis of biomass with biopolymer waste are improved compared to flash pyrolysis of pure willow. Of all the biopolymers under investigation, polyhydroxybutyrate (PHB) is the most promising, followed by Eastar, Biopearls, potato starch, polylactic acid (PLA), corn starch and Solanyl in order of decreasing profits. Taking into account uncertainties, flash co-pyrolysis is expected to be cheaper than composting biopolymer waste streams, except for corn starch. If uncertainty increases, composting also becomes more interesting than flash co-pyrolysis for waste of Solanyl. If the investment expenditure is 15% higher in practice than estimated, the preference for flash co-pyrolysis compared to composting biopolymer waste becomes less clear. Only when the system of green current certificates is dismissed, composting clearly is a much cheaper processing technique for disposing of biopolymer waste.

  18. In vitro assessment of biopolymer-modified porous silicon microparticles for wound healing applications.

    PubMed

    Mori, Michela; Almeida, Patrick V; Cola, Michela; Anselmi, Giulia; Mäkilä, Ermei; Correia, Alexandra; Salonen, Jarno; Hirvonen, Jouni; Caramella, Carla; Santos, Hélder A

    2014-11-01

    The wound healing stands as very complex and dynamic process, aiming the re-establishment of the damaged tissue's integrity and functionality. Thus, there is an emerging need for developing biopolymer-based composites capable of actively promoting cellular proliferation and reconstituting the extracellular matrix. The aims of the present work were to prepare and characterize biopolymer-functionalized porous silicon (PSi) microparticles, resulting in the development of drug delivery microsystems for future applications in wound healing. Thermally hydrocarbonized PSi (THCPSi) microparticles were coated with both chitosan and a mixture of chondroitin sulfate/hyaluronic acid, and subsequently loaded with two antibacterial model drugs, vancomycin and resveratrol. The biopolymer coating, drug loading degree and drug release behavior of the modified PSi microparticles were evaluated in vitro. The results showed that both the biopolymer coating and drug loading of the THCPSi microparticles were successfully achieved. In addition, a sustained release was observed for both the drugs tested. The viability and proliferation profiles of a fibroblast cell line exposed to the modified THCPSi microparticles and the subsequent reactive oxygen species (ROS) production were also evaluated. The cytotoxicity and proliferation results demonstrated less toxicity for the biopolymer-coated THCPSi microparticles at different concentrations and time points comparatively to the uncoated counterparts. The ROS production by the fibroblasts exposed to both uncoated and biopolymer-coated PSi microparticles showed that the modified PSi microparticles did not induce significant ROS production at the concentrations tested. Overall, the biopolymer-based PSi microparticles developed in this study are promising platforms for wound healing applications.

  19. Submicro foaming in biopolymers by UV pulsed laser irradiation

    NASA Astrophysics Data System (ADS)

    Oujja, Mohamed; Rebollar, Esther; Gaspard, Solenne; Abrusci, Concepción; Catalina, Fernando; Lazare, Sylvain; Castillejo, Marta

    2006-05-01

    Microstructuring of polymers and biopolymers is of application in medical technology and biotechnology. Using different fabrication techniques three-dimensionally shaped and micro structured constructs can be developed for drug release and tissue engineering. As an alternative method, laser microstructuring offers a series of advantages including high resolution capability, low heat deposition in the substrate and high level of flexibility. In this work we present evidence of laser microfoam formation in collagen and gelatine by nanosecond pulsed laser irradiation in the UV at 248 and 266 nm. Irradiation at 355 nm produces melting followed by resolidification of the substrate, whereas irradiation at 532 and 1064 nm induces the formation of craters of irregular contours. Single pulse irradiation of a collagen film with an homogenized KrF microbeam yields a 20 μm thick expanded layer, which displays the interesting features of a nanofibrous 3-dimensional network with open cells. In gelatine, irradiation at 248 and 266 nm produces similar morphological modifications. The effect of the structural properties of the substrate on the laser induced microfoam is studied by comparing gelatines differing in gel strength (Bloom values 225 and 75) and in crosslinking degree. While results are discussed on the basis of thermal and photomechanical mechanisms and of the role played by the water content of the substrates, it is thought that such structures could have a biomimic function in future 3D cell culture devices for research.

  20. Processing parameters matching effects upon Rhizobium tropici biopolymers' rheological properties.

    PubMed

    Pimenta, Flávia Duta; Lopes, Léa Maria de Almeida; de França, Francisca Pessôa

    2008-07-01

    The combined effects of the processing parameters upon rheological properties of biopolymers produced by Rhizobium tropici were studied as a function of the Ca(+2) ions' concentration variation, yeast extract concentration added to the medium, aeration, and agitation, maintaining the mannitol concentration in 10 g/L. The experiments were carried out using a fermenter with 20-L capacity as a reactor. All processing parameters were monitored online. The temperature [(30 +/- 1) degrees C] and pH values (7.0) were kept constant throughout the experimental time. As a statistical tool, a complete 2(3) factorial design with central point and response surface was used to investigate the interactions between relevant variables of the fermentation process: calcium carbonate concentration, yeast extract concentration, aeration, and agitation. The processing parameter setup for reaching the maximum response for rheological propriety production was obtained when applying mannitol concentration of 10.0 g/L, calcium carbonate concentration 1.0 g/L, yeast extract concentration 1.0 g/L, aeration 1.30 vvm, and agitation 800 rpm. The viscosimetric investigation of polysaccharide solutions exposed their shear-thinning behavior and polyelectrolytic feature.

  1. Dynamic light scattering of xanthan gum biopolymer in colloidal dispersion.

    PubMed

    Rahdar, Abbas; Almasi-Kashi, Mohammad

    2016-09-01

    The dynamical properties of nanogels of xanthan gum (XG) with hydrodynamic radius controlled in a size range from 5 nm to 35 nm, were studied at the different XG concentrations in water/sodium bis-2-ethylhexyl-sulfosuccinate (AOT)/decane reverse micelles (RMs) vs. mass fraction of nano-droplet (MFD) at W = 40, using dynamic light scattering (DLS). The diffusion study of nanometer-sized droplets by DLS technique indicated that enhancing concentration of the XG polysaccharide resulted in exchanging the attractive interaction between nano-gels to repulsive interaction, as the mass fraction of nano-droplets increased. The reorientation time (τr ) of water nanodroplets decreased with MFD for water-in-oil AOT micro-emulsion comprising high concentration (0.0000625) of XG. On the other hand, decreasing concentration of biopolymer led to increasing the rotational correlation time of water nanodroplets with MFD. In conclusion, a single relaxation curve was observed for AOT inverse microemulsions containing different XG concentrations. Furthermore, the interaction between nanogels was changed from attractive to repulsive versus concentration of XG in the AOT RMs.

  2. Elasticity of cross-linked semiflexible biopolymers under tension.

    PubMed

    von der Heydt, Alice; Wilkin, Daniel; Benetatos, Panayotis; Zippelius, Annette

    2013-09-01

    Aiming at the mechanical properties of cross-linked biopolymers, we set up and analyze a model of two weakly bending wormlike chains subjected to a tensile force, with regularly spaced inter-chain bonds (cross-links) represented by harmonic springs. Within this model, we compute the force-extension curve and the differential stiffness exactly and discuss several limiting cases. Cross-links effectively stiffen the chain pair by reducing thermal fluctuations transverse to the force and alignment direction. The extra alignment due to cross-links increases both with growing number and with growing strength of the cross-links, and is most prominent for small force f. For large f, the additional, cross-link-induced extension is subdominant except for the case of linking the chains rigidly and continuously along their contour. In this combined limit, we recover asymptotically the elasticity of a weakly bending wormlike chain without constraints, stiffened by a factor of 4. The increase in differential stiffness can be as large as 100% for small f or large numbers of cross-links.

  3. Phase Segregation in Individually Dried Particles Composed of Biopolymers.

    PubMed

    Nuzzo, Marine; Sloth, Jakob; Bergenstahl, Björn; Millqvist-Fureby, Anna

    2015-10-13

    Mixing of two biopolymers can results in phase separation due to their thermodynamically incompatibility under certain conditions. This phenomenon was first reported when the solution was allowed to equilibrate, but it has later been observed also as a consequence of drying. The challenges of this study were to observe phase segregation by confocal Raman microscopy and LV-SEM on dried film, individually dried particles, and spray dried particles. The influence of the solid content and the phase ratio (composition) of a HPMC/maltodextrin mixture on the localization of the ingredients in the individually dried particles was investigated. We observed that phase segregation of HPMC and maltodextrin is induced by solvent evaporation in film drying, single particle drying, as well as spray drying. The phase ratio is an important parameter that influences the localization of the HPMC-enriched phase and maltodextrin-enriched phase, i.e., to the particle surface, to the core, or in a more or less bicontinuous pattern. The drying time, affected by the solids content, was found to control the level of advancement of the phase segregation.

  4. Strain induced critical behavior in athermal biopolymer networks

    NASA Astrophysics Data System (ADS)

    Sharma, Abhinav; Licup, Albert; Rens, Robbie; Sheinman, Michael; Jansen, Karin; Koenderink, Gijse; Mackintosh, Fred

    2015-03-01

    Biopolymer networks exhibit highly interesting mechanical behavior. An instructive model system is that of a network composed of rope-like filaments-zero resistance to compression but finite resistance to stretching. For networks with connectivity below Maxwell point,there is no elastic modulus for small deformations. However,when networks are subjected to an external strain, stiffness emerges spontaneously beyond a critical strain. We demonstrate that the spontaneous emergence of elasticity is analogous to a continuous phase transition. The critical point is not fixed but depends on the geometry of the underlying network.The elastic behavior near the critical point can be described analogous to that of Magnetization in ferromagnetic material near the curie temperature.Surprisingly, the critical exponents are independent of the dimensionality and depend only on the average connectivity in the network.By including bending interactions in the rope network, we can capture the mechanical behavior of biologically relevant networks.Bending rigidity acts as a coupling constant analogous to the external magnetic field in a ferromagnetic system.We show that nonlinear mechanics of collagen are successfully captured by our framework of regarding nonlinear mechanics as a critical phenomenon

  5. Injectable biopolymer based hydrogels for drug delivery applications.

    PubMed

    Atta, Sadia; Khaliq, Shaista; Islam, Atif; Javeria, Irtaza; Jamil, Tahir; Athar, Muhammad Makshoof; Shafiq, Muhammad Imtiaz; Ghaffar, Abdul

    2015-09-01

    Biopolymer based pH-sensitive hydrogels were prepared using chitosan (CS) with polyethylene glycol (PEG) of different molecular weights in the presence of silane crosslinker. The incorporated components remain undissolved in different swelling media as they are connected by siloxane linkage which was confirmed by Fourier transform infrared spectroscopy. The swelling in water was enhanced by the addition of higher molecular weight PEG. The swelling behaviour of the hydrogels against pH showed high swelling in acidic and basic pH, whereas, low swelling was examined at pH 6 and 7. This characteristic pH responsive behaviour at neutral pH made them suitable for injectable controlled drug delivery. The controlled release analysis of Cefixime (CFX) (model drug) loaded CS/PEG hydrogel exhibited that the entire drug was released in 30 min in simulated gastric fluid (SGF) while in simulated intestinal fluid (SIF), 85% of drug was released in controlled manner within 80 min. This inferred that the developed hydrogels can be an attractive biomaterial for injectable drug delivery with physiological pH and other biomedical applications.

  6. Probe diffusion in phase-separated bicontinuous biopolymer gels.

    PubMed

    Wassén, Sophia; Bordes, Romain; Gebäck, Tobias; Bernin, Diana; Schuster, Erich; Lorén, Niklas; Hermansson, Anne-Marie

    2014-11-07

    Probe diffusion was determined in phase separated bicontinuous gels prepared by acid-induced gelation of the whey protein isolate-gellan gum system. The topological characterization of the phase-separated gel systems is achieved by confocal microscopy and the diffusion measurements are performed using pulsed field gradient (PFG) NMR and fluorescence recovery after photo-bleaching (FRAP). These two techniques gave complementary information about the mass transport at different time- and length scales, PFG NMR provided global diffusion rates in the gel systems, while FRAP enabled the measurements of diffusion in different phases of the phase-separated gels. The results revealed that the phase-separated gel with the largest characteristic wavelength had the fastest diffusion coefficient, while the gel with smaller microstructures had a slower probe diffusion rate. By using the diffusion data obtained by FRAP and the structural data from confocal microscopy, modelling through the lattice-Boltzmann framework was carried out to simulate the global diffusion and verify the validity of the experimental measurements. With this approach it was found that discrepancies between the two experimental techniques can be rationalized in terms of probe distribution between the different phases of the system. The combination of different techniques allowed the determination of diffusion in a phase-separated biopolymer gel and gave a clearer picture of this complex system. We also illustrate the difficulties that can arise if precautions are not taken to understand the system-probe interactions.

  7. Abundances of Elements in Stellar Coronae

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy

    1998-01-01

    Interest in stellar coronal abundances was piqued several years ago by the launch of satellites that were able to study the compositions of coronae on stars other than the sun. Motivated by the possibility that other stellar coronae might share the First Ionization Potential (FIP) Effect solar abundance anomaly, we have in recent years been attempting to determine coronal element abundances in other stars. I will review these results, together with similar results reported in the literature, from a critical perspective of understanding the true uncertainties involved in the measurements. The importance of element abundances for coronal physics will be highlighted, and it will be shown that the differences in the chemical compositions of active stars allow us to draw new conclusions regarding the nature of stellar coronae and coronal heating.

  8. Ammonia abundances in comets

    NASA Astrophysics Data System (ADS)

    Wyckoff, S.; Tegler, S.; Engel, L.

    The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

  9. Does the ligand-biopolymer equilibrium binding constant depend on the number of bound ligands?

    PubMed

    Beshnova, Daria A; Lantushenko, Anastasia O; Evstigneev, Maxim P

    2010-11-01

    Conventional methods, such as Scatchard or McGhee-von Hippel analyses, used to treat ligand-biopolymer interactions, indirectly make the assumption that the microscopic binding constant is independent of the number of ligands, i, already bound to the biopolymer. Recent results on the aggregation of aromatic molecules (Beshnova et al., J Chem Phys 2009, 130, 165105) indicated that the equilibrium constant of self-association depends intrinsically on the number of molecules in an aggregate due to loss of translational and rotational degrees of freedom on formation of the complex. The influence of these factors on the equilibrium binding constant for ligand-biopolymer complexation was analyzed in this work. It was shown that under the conditions of binding of "small" molecules, these factors can effectively be ignored and, hence, do not provide any hidden systematic error in such widely-used approaches, such as the Scatchard or McGhee-von Hippel methods for analyzing ligand-biopolymer complexation. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 932-935, 2010.

  10. Spectral analysis methods for the robust measurement of the flexural rigidity of biopolymers.

    PubMed

    Valdman, David; Atzberger, Paul J; Yu, Dezhi; Kuei, Steve; Valentine, Megan T

    2012-03-07

    The mechanical properties of biopolymers can be determined from a statistical analysis of the ensemble of shapes they exhibit when subjected to thermal forces. In practice, extracting information from fluorescence microscopy images can be challenging due to low signal/noise ratios and other artifacts. To address these issues, we develop a suite of tools for image processing and spectral data analysis that is based on a biopolymer contour representation expressed in a spectral basis of orthogonal polynomials. We determine biopolymer shape and stiffness using global fitting routines that optimize a utility function measuring the amount of fluorescence intensity overlapped by such contours. This approach allows for filtering of high-frequency noise and interpolation over sporadic gaps in fluorescence. We use benchmarking to demonstrate the validity of our methods, by analyzing an ensemble of simulated images generated using a simulated biopolymer with known stiffness and subjected to various types of image noise. We then use these methods to determine the persistence lengths of taxol-stabilized microtubules. We find that single microtubules are well described by the wormlike chain polymer model, and that ensembles of chemically identical microtubules show significant heterogeneity in bending stiffness, which cannot be attributed to sampling or fitting errors. We expect these approaches to be useful in the study of biopolymer mechanics and the effects of associated regulatory molecules.

  11. Encapsulation of lead from hazardous CRT glass wastes using biopolymer cross-linked concrete systems

    SciTech Connect

    Kim, Daeik; Quinlan, Michael; Yen, Teh Fu

    2009-01-15

    Discarded computer monitors and television sets are identified as hazardous materials due to the high content of lead in their cathode ray tubes (CRTs). Over 98% of lead is found in CRT glass. More than 75% of obsolete electronics including TV and CRT monitors are in storage because appropriate e-waste management and remediation technologies are insufficient. Already an e-waste tsunami is starting to roll across the US and the whole world. Thus, a new technology was developed as an alternative to current disposal methods; this method uses a concrete composite crosslinked with minute amounts of biopolymers and a crosslinking agent. Commercially available microbial biopolymers of xanthan gum and guar gum were used to encapsulate CRT wastes, reducing Pb leachability as measured by standard USEPA methods. In this investigation, the synergistic effect of the crosslinking reaction was observed through blending two different biopolymers or adding a crosslinking agent in biopolymer solution. This CRT-biopolymer-concrete (CBC) composite showed higher compressive strength than the standard concrete and a considerable decrease in lead leachability.

  12. Influence of different treatment condition on biopolymer yield production for coagulation-flocculation process

    NASA Astrophysics Data System (ADS)

    Aisyah, I. S.; Murshed, M. F.; Norli, I.

    2016-06-01

    Two different agro wastes (banana pseudostem and rice straw) were utilized in order to extract biopolymer (pectin) known as coagulant aid in water and wastewater treatment. Factors such as pH, temperature and time were chosen due to the critical role in hot acid extraction process. The yield of biopolymer extraction from banana pseudostem was found to be higher at 28% meanwhile only 18% from rice straw was manage to produce from the dry weight 10 g, respectively. It was found that extraction temperature and extraction time were the most important factors influencing the biopolymer yield which increased with temperature and time or decreasing pH. Based on two level factorial design, the same condition of pH 1.5, temperature 90 oC and 4 hours extraction time can produce high amount of extracted biopolymer. Fourier Transform Infrared Spectroscopy (FTIR) was used to detect the existence of functional group which helps in the coagulation-flocculation process. Result indicates a similar functional group of biopolymer were detected for both difference agro wastes.

  13. Encapsulation of lead from hazardous CRT glass wastes using biopolymer cross-linked concrete systems.

    PubMed

    Kim, Daeik; Quinlan, Michael; Yen, Teh Fu

    2009-01-01

    Discarded computer monitors and television sets are identified as hazardous materials due to the high content of lead in their cathode ray tubes (CRTs). Over 98% of lead is found in CRT glass. More than 75% of obsolete electronics including TV and CRT monitors are in storage because appropriate e-waste management and remediation technologies are insufficient. Already an e-waste tsunami is starting to roll across the US and the whole world. Thus, a new technology was developed as an alternative to current disposal methods; this method uses a concrete composite crosslinked with minute amounts of biopolymers and a crosslinking agent. Commercially available microbial biopolymers of xanthan gum and guar gum were used to encapsulate CRT wastes, reducing Pb leachability as measured by standard USEPA methods. In this investigation, the synergistic effect of the crosslinking reaction was observed through blending two different biopolymers or adding a crosslinking agent in biopolymer solution. This CRT-biopolymer-concrete (CBC) composite showed higher compressive strength than the standard concrete and a considerable decrease in lead leachability.

  14. Vibrational spectroscopic studies of newly developed synthetic biopolymers.

    PubMed

    Bista, Rajan K; Bruch, Reinhard F; Covington, Aaron M

    2010-05-01

    Vibrational spectroscopic techniques such as near-infrared (NIR), Fourier transform infrared (FTIR), and Raman spectroscopy are valuable diagnostic tools that can be used to elucidate comprehensive structural information of numerous biological samples. In this review article, we have highlighted the advantages of nanotechnology and biophotonics in conjunction with vibrational spectroscopic techniques in order to understand the various aspects of new kind of synthetic biopolymers termed as polyethylene glycol (PEG)ylated lipids. In contrast to conventional phospholipids, these novel lipids spontaneously form liposomes or nanovesicles upon hydration, without the supply of external activation energy. The amphiphiles considered in this study differ in their hydrophobic acyl chain length and contain different units of PEG hydrophilic headgroups. We have further explored the thermotropic phase behaviors and associated changes in the conformational order/disorder of such lipids by using variable-temperature FTIR and Raman spectroscopy. Phase transition temperature profiles and correlation between various spectral indicators have been identified by either monitoring the shifts in the vibrational peak positions or plotting vibrational peak intensity ratios in the C--H stretching region as a function of temperature. To supplement our observations of phase transformations, a thermodynamic approach known as differential scanning calorimetry (DSC) has been applied and revealed a good agreement with the infrared and Raman spectroscopic data. Finally, the investigation of thermal properties of lipids is extremely crucial for numerous purposes, thus the results obtained in this work may find application in a wide variety of studies including the development of PEGylated lipid based drug and substances delivery vehicles.

  15. Enzyme and metabolic engineering for the production of novel biopolymers: crossover of biological and chemical processes.

    PubMed

    Matsumoto, Ken'ichiro; Taguchi, Seiichi

    2013-12-01

    The development of synthetic biology has transformed microbes into useful factories for producing valuable polymers and/or their precursors from renewable biomass. Recent progress at the interface of chemistry and biology has enabled the production of a variety of new biopolymers with properties that substantially differ from their petroleum-derived counterparts. This review touches on recent trials and achievements in the field of biopolymer synthesis, including chemo-enzymatically synthesized aliphatic polyesters, wholly biosynthesized lactate-based polyesters, polyhydroxyalkanoates and other unusual bacterially synthesized polyesters. The expanding diversities in structure and the material properties of biopolymers are key for exploring practical applications. The enzyme and metabolic engineering approaches toward this goal are discussed by shedding light on the successful case studies.

  16. Nanostructured Materials Utilized in Biopolymer-based Plastics for Food Packaging Applications.

    PubMed

    Ghanbarzadeh, Babak; Oleyaei, Seyed Amir; Almasi, Hadi

    2015-01-01

    Most materials currently used for food packaging are nondegradable, generating environmental problems. Several biopolymers have been exploited to develop materials for ecofriendly food packaging. However, the use of biopolymers has been limited because of their usually poor mechanical and barrier properties, which may be improved by adding reinforcing compounds (fillers), forming composites. Most reinforced materials present poor matrix-filler interactions, which tend to improve with decreasing filler dimensions. The use of fillers with at least one nanoscale dimension (nanoparticles) produces nanocomposites. Nanoparticles have proportionally larger surface area than their microscale counterparts, which favors the filler-matrix interactions and the performance of the resulting material. Besides nanoreinforcements, nanoparticles can have other functions when added to a polymer, such as antimicrobial activity, etc. in this review paper, the structure and properties of main kinds of nanostructured materials which have been studied to use as nanofiller in biopolymer matrices are overviewed, as well as their effects and applications.

  17. Performance of an electro-optic waveguide modulator fabricated using a deoxyribonucleic-acid-based biopolymer

    NASA Astrophysics Data System (ADS)

    Heckman, Emily M.; Grote, James G.; Hopkins, F. Kenneth; Yaney, Perry P.

    2006-10-01

    An electro-optic (EO) planar waveguide modulator using a deoxyribonucleic acid (DNA)-based biopolymer for both the waveguide core and cladding layers has been fabricated and its performance evaluated. A cross-linked DNA-surfactant biopolymer was used for the top and bottom cladding layers and the core layer was a cross-linked DNA-surfactant biopolymer with 3wt% Disperse Red 1. The EO coefficient r33 was induced through contact poling. The fabricated device was found to exhibit EO modulating behavior. Using an estimated value of r33=0.5pm/V, a sine-squared fit to the modulating data was obtained with Vπ=263V±10%.

  18. Human elastin-based recombinant biopolymers improve mesenchymal stem cell differentiation.

    PubMed

    Çelebi, Betül; Cloutier, Maxime; Rabelo, Rodrigo B; Balloni, Rodrigo; Mantovani, Diego; Bandiera, Antonella

    2012-11-01

    Elastin-based polypeptides are a class of smart biopolymers representing an important model in the design of biomaterials. The combination of biomimetic materials with cells that have great plasticity provides a promising strategy for the realization of highly engineered cell-based constructs for regenerative medicine and tissue repair applications. Two recombinant biopolymers inspired by human elastin are assessed as coating agents to prepare biomimetic surfaces for cell culture. These substrates are assayed for hBM MSC culture. The coated surfaces are also characterized with AFM to evaluate the topographical features of the deposited biopolymers. The results suggest that the elastin-derived biomimetic surfaces play a stimulatory role on osteogenic differentiation of MSCs.

  19. Flare Plasma Iron Abundance

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Dan, Chau; Jain, Rajmal; Schwartz, Richard A.; Tolbert, Anne K.

    2008-01-01

    The equivalent width of the iron-line complex at 6.7 keV seen in flare X-ray spectra suggests that the iron abundance of the hottest plasma at temperatures >approx.10 MK may sometimes be significantly lower than the nominal coronal abundance of four times the photospheric value that is commonly assumed. This conclusion is based on X-ray spectral observations of several flares seen in common with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Solar X-ray Spectrometer (SOXS) on the second Indian geostationary satellite, GSAT-2. The implications of this will be discussed as it relates to the origin of the hot flare plasma - either plasma already in the corona that is directly heated during the flare energy release process or chromospheric plasma that is heated by flare-accelerated particles and driven up into the corona. Other possible explanations of lower-than-expected equivalent widths of the iron-line complex will also be discussed.

  20. Adsorption of toxic mercury(II) by an extracellular biopolymer poly(gamma-glutamic acid).

    PubMed

    Inbaraj, B Stephen; Wang, J S; Lu, J F; Siao, F Y; Chen, B H

    2009-01-01

    Adsorption of mercury(II) by an extracellular biopolymer, poly(gamma-glutamic acid) (gamma-PGA), was studied as a function of pH, temperature, agitation time, ionic strength, light and heavy metal ions. An appreciable adsorption occurred at pH>3 and reached a maximum at pH 6. Isotherms were well predicted by Redlich-Peterson model with a dominating Freundlich behavior, implying the heterogeneous nature of mercury(II) adsorption. The adsorption followed an exothermic and spontaneous process with increased orderliness at solid/solution interface. The adsorption was rapid with 90% being attained within 5 min for a 80 mg/L mercury(II) solution, and the kinetic data were precisely described by pseudo second order model. Ionic strength due to added sodium salts reduced the mercury(II) binding with the coordinating ligands following the order: Cl(-) >SO(4)(2-) >NO(3)(-). Both light and heavy metal ions decreased mercury(II) binding by gamma-PGA, with calcium(II) ions showing a more pronounced effect than monovalent sodium and potassium ions, while the interfering heavy metal ions followed the order: Cu(2+) > Cd(2+) > Zn(2+). Distilled water adjusted to pH 2 using hydrochloric acid recovered 98.8% of mercury(II), and gamma-PGA reuse for five cycles of operation showed a loss of only 6.5%. IR spectra of gamma-PGA and Hg(II)-gamma-PGA revealed binding of mercury(II) with carboxylate and amide groups on gamma-PGA.

  1. Oxygen abundance and convection

    NASA Astrophysics Data System (ADS)

    Van't Veer, C.; Cayrel, R.

    The triplet IR lines of O I near 777 nm are computed with the Kurucz's code, modified to accept several convection models. The program has been run with the MLT algorithm, with l/H = 1.25 and 0.5, and with the Canuto-Mazzitelli and Canuto-Goldman-Mazzitelli approaches, on a metal-poor turnoff-star model atmosphere with Teff=6200 K, log g = 4.3, [Fe/H]= -1.5. The results show that the differences in equivalent widths for the 4 cases do not exceed 2 per cent (0.3 mA). The convection treatment is therefore not an issue for the oxygen abundance derived from the permitted lines.

  2. Removal of glyphosate herbicide from water using biopolymer membranes.

    PubMed

    Carneiro, Rafael T A; Taketa, Thiago B; Gomes Neto, Reginaldo J; Oliveira, Jhones L; Campos, Estefânia V R; de Moraes, Mariana A; da Silva, Camila M G; Beppu, Marisa M; Fraceto, Leonardo F

    2015-03-15

    treat a water sample contaminated with glyphosate. Biopolymer membranes therefore potentially offer a versatile method to eliminate agricultural chemicals from water supplies.

  3. Biopolymers produced from gelatin and chitosan using polyphenols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chitin, and its derivative chitosan, is an abundant waste product derived from crustaceans (e.g. crab). It has unique properties which enable its use in, but not limited to, cosmetic, medical, and food applications. Chitosan has recently been studied, in conjunction with other waste carbohydrates ...

  4. Chemical Abundances of Compact Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Lee, Ting-Hui; Shaw, Richard A.; Stanghellini, letizia; Riley, Ben

    2015-08-01

    We present preliminary results from an optical spectroscopic survey of compact planetary nebulae (PNe) in the Galactic disk. This is an ongoing optical+infrared spectral survey of 150 compact PNe to build a deep sample of PN chemical abundances. We obtained optical spectra of PNe with the Southern Astrophysical Research (SOAR) Telescope and Goodman High-Throughput Spectrograph between 2012 and 2015. These data were used to calculate the nebulae diagnostics such as electron temperature and density for each PN, and to derive the elemental abundances of He, N, O Ne, S and Ar. These abundances are vital to understanding the nature of the PNe, and their low- to intermediate-mass progenitor stars.

  5. A review of combined experimental and computational procedures for assessing biopolymer structure–process–property relationships

    PubMed Central

    Gronau, Greta; Krishnaji, Sreevidhya T.; Kinahan, Michelle E.; Giesa, Tristan; Wong, Joyce Y.; Kaplan, David L.; Buehler, Markus J.

    2013-01-01

    Tailored biomaterials with tunable functional properties are desirable for many applications ranging from drug delivery to regenerative medicine. To improve the predictability of biopolymer materials functionality, multiple design parameters need to be considered, along with appropriate models. In this article we review the state of the art of synthesis and processing related to the design of biopolymers, with an emphasis on the integration of bottom-up computational modeling in the design process. We consider three prominent examples of well-studied biopolymer materials – elastin, silk, and collagen – and assess their hierarchical structure, intriguing functional properties and categorize existing approaches to study these materials. We find that an integrated design approach in which both experiments and computational modeling are used has rarely been applied for these materials due to difficulties in relating insights gained on different length- and time-scales. In this context, multiscale engineering offers a powerful means to accelerate the biomaterials design process for the development of tailored materials that suit the needs posed by the various applications. The combined use of experimental and computational tools has a very broad applicability not only in the field of biopolymers, but can be exploited to tailor the properties of other polymers and composite materials in general. PMID:22938765

  6. Stable silver/biopolymer hybrid plasmonic nanostructures for high performance surface enhanced raman scattering (SERS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silver/biopolymer nanoparticles were prepared by adding 100 mg silver nitrate to 2% polyvinyl alcohol solution and reduced the silver nitrate into silver ion using 2 % trisodium citrate for high performance Surface Enhanced Raman Scattering (SERS) substrates. Optical properties of nanoparticle were ...

  7. Micro-heterogeneity of corn hulls cellulosic fiber biopolymer studied by multiple-particle tracking (MPT)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel technique named multiple-particle tracking (MPT) was used to investigate the micro-structural heterogeneities of Z-trim, a zero calorie cellulosic fiber biopolymer produced from corn hulls. The Multiple-Particle Tracking (MPT) method was used in this study, which was originally described by ...

  8. Micro-heterogeneity of corn hulls cellulosic fiber biopolymer studied by multiple-particle tracking (MPT)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel technique named multiple-particle tracking (MPT) was used to investigate the micro-structural heterogeneities of Z-trim, a zero calorie cellulosic fiber biopolymer produced from corn hulls. The principle of MPT technique is to monitor the thermally driven motion of inert micro-spheres, which...

  9. Development of a biopolymer nanoparticle-based method of oral toxicity testing in aquatic invertebrates.

    PubMed

    Gott, Ryan C; Luo, Yangchao; Wang, Qin; Lamp, William O

    2014-06-01

    Aquatic toxicity testing generally focuses on the water absorption/dermal route of exposure to potential toxic chemicals, while much less work has been done on the oral route of exposure. This is due in part to the difficulties of applying traditional oral toxicity testing to aquatic environments, including the tendency for test chemicals to dissolve into water. The use of biopolymer nanoparticles to encapsulate test chemicals onto food to prevent dissolution is one solution presented herein. The biopolymers zein and chitosan were explored for their previously known nanoparticle-forming abilities. Nanoparticles containing the test chemical rhodamine B were formed, applied as films to coat food, and then fed to the test organism, the freshwater amphipod Hyalella azteca. In feeding trials both zein and chitosan nanoparticles showed a significantly lower release rate of rhodamine B into water than food dyed with rhodamine B without biopolymer nanoparticles. Zein nanoparticles also showed better retention ability than chitosan nanoparticles. Both kinds of nanoparticles showed no significant effect on the survival, growth, or feeding behavior of H. azteca. Thus these biopolymers may be an effective system to encapsulate and deliver chemicals to aquatic invertebrates without interfering with common toxicity assessment endpoints like survival and growth.

  10. Enzymatic functionalization of cork surface with antimicrobial hybrid biopolymer/silver nanoparticles.

    PubMed

    Francesko, Antonio; Blandón, Lucas; Vázquez, Mario; Petkova, Petya; Morató, Jordi; Pfeifer, Annett; Heinze, Thomas; Mendoza, Ernest; Tzanov, Tzanko

    2015-05-13

    Laccase-assisted assembling of hybrid biopolymer-silver nanoparticles and cork matrices into an antimicrobial material with potential for water remediation is herein described. Amino-functional biopolymers were first used as doping agents to stabilize concentrated colloidal dispersions of silver nanoparticles (AgNP), additionally providing the particles with functionalities for covalent immobilization onto cork to impart a durable antibacterial effect. The solvent-free AgNP synthesis by chemical reduction was carried out in the presence of chitosan (CS) or 6-deoxy-6-(ω-aminoethyl) aminocellulose (AC), leading to simultaneous AgNP biofunctionalization. This approach resulted in concentrated hybrid NP dispersion stable to aggregation and with hydrodynamic radius of particles of about 250 nm. Moreover, laccase enabled coupling between the phenolic groups in cork and amino moieties in the biopolymer-doped AgNP for permanent modification of the material. The antibacterial efficiency of the functionalized cork matrices, aimed as adsorbents for wastewater treatment, was evaluated against Escherichia coli and Staphylococcus aureus during 5 days in conditions mimicking those in constructed wetlands. Both intrinsically antimicrobial CS and AC contributed to the bactericidal effect of the enzymatically grafted on cork AgNP. In contrast, unmodified AgNP were easily washed off from the material, confirming that the biopolymers potentiated a durable antibacterial functionalization of the cork matrices.

  11. Derivation of a variational principle for plane strain elastic-plastic silk biopolymers

    NASA Astrophysics Data System (ADS)

    He, J. H.; Liu, F. J.; Cao, J. H.; Zhang, L.

    2014-01-01

    Silk biopolymers, such as spider silk and Bombyx mori silk, behave always elastic-plastically. An elastic-plastic model is adopted and a variational principle for the small strain, rate plasticity problem is established by semi-inverse method. A trial Lagrangian is constructed where an unknown function is included which can be identified step by step.

  12. Effect of Conformation and Drop Properties on Surface-Enhanced Raman Spectroscopy of Dried Biopolymer Drops

    PubMed Central

    Esmonde-White, Karen A.; Le Clair, Stephanie V.; Roessler, Blake J.; Morris, Michael D.

    2011-01-01

    Biofluids are complex solutions consisting of small ions and large biopolymers such as DNA, proteins or proteoglycans. Biopolymers affect fluid properties but their effect on drop deposition has not been examined. Hyaluronic acid (HA), an important component in synovial fluid, was chosen as a model biopolymer, and examined using surface-enhanced Raman spectroscopy (SERS). Nanoliter volumes of HA solutions were dried onto a patterned SERS substrate and spectra were collected from the dried hyaluronic acid drops with a near-infrared Raman microscope. Characteristic hyaluronic acid bands were examined. Capillary viscometry measured properties of HA solutions and entanglement behavior was also modeled using scaling theory principles. Viscosity measurements were incorporated into models of suspended particle droplets to account for the effect of inter-chain attraction on droplet formation. Microscope images were used to evaluate shape of the dried drop. Relative drop thickness was estimated from concentric rings found at drop edges using established models of light interference by thin films. We found SERS spectra were sensitive not only to polymer conformation, but also to type of deposition (ring versus uniform), and the thickness of the resulting deposition. These data suggest an approach to elucidate the effects of biopolymers and dehydrated biofluids on SERS analysis. PMID:18498691

  13. Dihedral-based segment identification and classification of biopolymers I: proteins.

    PubMed

    Nagy, Gabor; Oostenbrink, Chris

    2014-01-27

    A new structure classification scheme for biopolymers is introduced, which is solely based on main-chain dihedral angles. It is shown that by dividing a biopolymer into segments containing two central residues, a local classification can be performed. The method is referred to as DISICL, short for Dihedral-based Segment Identification and Classification. Compared to other popular secondary structure classification programs, DISICL is more detailed as it offers 18 distinct structural classes, which may be simplified into a classification in terms of seven more general classes. It was designed with an eye to analyzing subtle structural changes as observed in molecular dynamics simulations of biomolecular systems. Here, the DISICL algorithm is used to classify two databases of protein structures, jointly containing more than 10 million segments. The data is compared to two alternative approaches in terms of the amount of classified residues, average occurrence and length of structural elements, and pair wise matches of the classifications by the different programs. In an accompanying paper (Nagy, G.; Oostenbrink, C. Dihedral-based segment identification and classification of biopolymers II: Polynucleotides. J. Chem. Inf. Model. 2013, DOI: 10.1021/ci400542n), the analysis of polynucleotides is described and applied. Overall, DISICL represents a potentially useful tool to analyze biopolymer structures at a high level of detail.

  14. A novel method to analyze the degree of acetylation in biopolymers.

    PubMed

    Zweckmair, T; Becker, M; Ahn, K; Hettegger, H; Kosma, P; Rosenau, T; Potthast, A

    2014-10-31

    A novel approach to measure the degree of acetylation in biopolymers applying a combination of Zemplén-deacetylation by sodium methanolate and GC-MS methodology is introduced. The development focuses on very low limits of detection to cover also samples with extremely low degrees of acetylation which hitherto eluded accurate determination. Free acetic acid or inorganic acetates, often present in biopolymer samples, do not disturb the quantification. Two techniques to measure the Zemplén-released methyl acetate were comparatively assessed, direct injection of the liquid phase and a SPME-based approach, the former being more straightforward, but being inferior to the latter in sensitivity. By applying isotopically labeled methyl acetate released from 4-O-((13)C2-acetyl)-vanillin as the internal standard, influences, such as varying moisture contents, are corrected, improving the overall method reliability to a large extent. The combination of Zemplén-release of acetyl groups in biopolymers as methyl acetate, in connection with its accurate quantification by SPME-GC-MS, was found to be the method of choice for routine, yet very accurate analysis of a wide range of acetylation degrees of biopolymers, showing satisfying analytical parameters along with easy handling and widest applicability. Limit of detection for acetylated cellulose samples is 0.09nmol/mg, for hemicellulose samples 0.48nmol/mg.

  15. MOLECULAR TRACERS FOR SMOKE FROM CHARRING/BURNING OF CHITIN BIOPOLYMER. (R823990)

    EPA Science Inventory

    Abstract

    Monosaccharide derivatives from the breakdown of cellulose are the major organic components of smoke particles emitted to the atmosphere from biomass burning. In urban areas a related biopolymer, chitin, may contribute markers to smoke from grilling/charring o...

  16. Single walled carbon nanotubes with functionally adsorbed biopolymers for use as chemical sensors

    DOEpatents

    Johnson, Jr., Alan T

    2013-12-17

    Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA or RNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

  17. Network and Nakamura tridiagonal computational simulation of electrically-conducting biopolymer micro-morphic transport phenomena.

    PubMed

    Anwar Bég, O; Zueco, J; Norouzi, M; Davoodi, M; Joneidi, A A; Elsayed, Assma F

    2014-01-01

    Magnetic fields have been shown to achieve excellent fabrication control and manipulation of conductive bio-polymer characteristics. To simulate magnetohydrodynamic effects on non-Newtonian electro-conductive bio-polymers (ECBPs) we present herein a theoretical and numerical simulation of free convection magneto-micropolar biopolymer flow over a horizontal circular cylinder (an "enrobing" problem). Eringen's robust micropolar model (a special case of the more general micro-morphic or "microfluid" model) is implemented. The transformed partial differential conservation equations are solved numerically with a powerful and new code based on NSM (Network Simulation Method) i.e. PSPICE. An extensive range of Hartmann numbers, Grashof numbers, micropolar parameters and Prandtl numbers are considered. Excellent validation is also achieved with earlier non-magnetic studies. Furthermore the present PSPICE code is also benchmarked with an implicit tridiagonal solver based on Nakamura's method (BIONAK) again achieving close correlation. The study highlights the excellent potential of both numerical methods described in simulating nonlinear biopolymer micro-structural flows.

  18. Natural and edible biopolymer poly-gamma-glutamic acid: synthesis, production, and applications.

    PubMed

    Sung, Moon-Hee; Park, Chung; Kim, Chul-Joong; Poo, Haryoung; Soda, Kenji; Ashiuchi, Makoto

    2005-01-01

    Poly-gamma-glutamic acid (gamma-PGA) is a very promising biodegradable polymer that is produced by Bacillus subtilis. Gamma-PGA is water-soluble, anionic, biodegradable, and edible. This paper reviews the production of a strain of gamma-PGA and recent developments with respect to applications in terms of Ca absorption, moisturizing properties, gamma-PGA conjugation, super absorbent polymer, and so on. Our recent research shows that gamma-PGA can be used as an immune-stimulating and anti-tumor agent, especially at high molecular weight.

  19. Nature's amazing biopolymer: basic mechanical and hydrological properties of soil affected by plant exudates

    NASA Astrophysics Data System (ADS)

    Naveed, Muhammad; Roose, Tiina; Raffan, Annette; George, Timothy; Bengough, Glyn; Brown, Lawrie; Keyes, Sam; Daly, Keith; Hallett, Paul

    2016-04-01

    Plant exudates are known to have a very large impact on soil physical properties through changes in mechanical and hydrological processes driven by long-chain polysaccharides and surface active compounds. Whilst these impacts are well known, the basic physical properties of these exudates have only been reported in a small number of studies. We present data for exudates obtained from barley roots and chia seeds, incorporating treatments examining biological decomposition of the exudates. When these exudates were added to a sandy loam soil, contact angle and drop penetration time increased exponentially with increasing exudate concentration. These wetting properties were strongly correlated with both exudate density and zero-shear viscosity, but not with exudate surface tension. Water holding capacity and water repellency of exudate mixed soil tremendously increased with exudate concentration, however they were significantly reduced on decomposition when measured after 14 days of incubation at 16C. Mechanical stability greatly increased with increasing exudate amendment to soils, which was assessed using a rheological amplitude sweep test near saturation, at -50 cm matric potential (field capacity) using indentation test, and at air-dry condition using the Brazilian test. This reflects that exudates not only attenuate plant water stress but also impart mechanical stability to the rhizosphere. These data are highly relevant to the understanding and modelling of rhizosphere development, which is the next phase of our research.

  20. Development of naturally activated edible films with antioxidant properties prepared from red seaweed Porphyra columbina biopolymers.

    PubMed

    Cian, Raúl E; Salgado, Pablo R; Drago, Silvina R; González, Rolando J; Mauri, Adriana N

    2014-03-01

    The aim of this work was to study the physicochemical and antioxidant properties of phycobiliproteins-phycocolloids-based films, obtained from mixtures of two aqueous fractions extracted from Porphyra columbina red seaweed, one enriched in phycocolloids (PcF) and the other in phycobiliproteins (PF). Films with different ratios of PF:PcF (0, 25, 50, 75, 100% [w/w]) and without plasticizer addition were prepared by casting. PcF films had excellent mechanical properties (tensile strength ∼50MPa, elongation at break ∼3% and an elastic modulus ∼17.5MPa). The addition of PF to formulations exerted a plasticizing effect on the PcF matrix, which was manifested in moisture content, water solubility and mechanical properties of the resulting films but not in its water vapour permeability. The antioxidant capacity (TEAC) of the PcF films was significantly increased by the addition of PF and a direct relationship between TEAC and the total phenolic compounds (r(2)=0.9998) and R-phycoerythrin (r(2)=0.9942) was observed.

  1. Capella: Structure and Abundances

    NASA Technical Reports Server (NTRS)

    Brickhouse, Nancy S.

    1999-01-01

    This grant covers the analysis of EUVE spectra of the cool star binary system Capella. This project has also required the analysis of simultaneous Advanced Satellite for Cosmology and Astrophysics (ASCA) data. The ASCA spectrum of Capella could not be fit with standard models; by imposing models based on strong lines observed with EUVE, a problem wavelength region was identified. Correcting the problem required calculations of atomic collision strengths of higher principal quantum number than had ever been calculated. With these new models applied to the ASCA spectrum, better fits were obtained. Findings are that: (1) ASCA and EUVE spectra are both dominated by a region at 6 x 10(exp 6) K. (2) The high energy cut-off of the ASCA spectrum is consistent with emission from the highest ionization stages of EUVE, namely Fe XXIV. (3) EUVE requires a continuous emission measure distribution with more than two temperatures. (4) The ASCA spectra are of such high statistical significance that systematic uncertainties dominate, including atomic physics issues and calibration issues. (5) While the ASCA spectral fits achieve lower Chi(exp 2 with two-temperature fits, the EUVE-derived emission measure distribution models are also consistent with the spectra. (6) The Fe/H ratio obtained from the ASCA fit is within 20 % of the Fe/H abundance obtained from the summed spectra of Capella over 5 EUVE pointings, as well as the 1996 EUVE data. This result confirms our claims that quasi-continua composed of weak emission lines in the short wavelength spectrometer of EUVE are not major contributors to the measured Capella continuum. Other abundance ratios are also determined from the ASCA data, using models derived with EUVE. Si, Si, and Mg appear to be close to solar photospheric values, while the ratio of Ne/Fe is three to four times lower than solar photospheric values. Whether there is a general First Ionization Potential (FIP) effect or a specific neon anomaly cannot be determined

  2. Actinide abundances in ordinary chondrites

    NASA Technical Reports Server (NTRS)

    Hagee, B.; Bernatowicz, T. J.; Podosek, F. A.; Johnson, M. L.; Burnett, D. S.

    1990-01-01

    Measurements of actinide and light REE (LREE) abundances and of phosphate abundances in equilibrated ordinary chondrites were obtained and were used to define the Pu abundance in the solar system and to determine the degree of variation of actinide and LREE abundances. The results were also used to compare directly the Pu/U ratio with the earlier obtained ratio determined indirectly, as (Pu/Nd)x(Nd/U), assuming that Pu behaves chemically as a LREE. The data, combined with high-accuracy isotope-dilution data from the literature, show that the degree of gram-scale variability of the Th, U, and LREE abundances for equilibrated ordinary chondrites is a factor of 2-3 for absolute abundances and up to 50 percent for relative abundances. The observed variations are interpreted as reflecting the differences in the compositions and/or proportions of solar nebula components accreted to ordinary chondrite parent bodies.

  3. Research and Development of Two Marine-Degradable Biopolymers.

    DTIC Science & Technology

    1992-03-01

    Ships 73F/78) mmole millimole ONT Office of Naval Technology PEG polyethylene glycol PHBV polyhydroxy butyrate valerate P.L. Public Law RTI Research... PHBV ), paper, and cot- ton textiles under the definition of plastics for the purposes of MARPOL Annex V. We have responded to the invitation for public...chitin/chitosan (the first and second most abundant bio- polymers, respe~ctively), there is also current interest in bacterial polyesters such as PHBV

  4. Biocompatibility of a Synthetic Biopolymer for the Treatment of Rhegmatogenous Retinal Detachment

    PubMed Central

    Sarfare, Shanta; Dacquay, Yann; Askari, Syed; Nusinowitz, Steven; Hubschman, Jean-Pierre

    2015-01-01

    Objective The aim of this study is to evaluate the retinal safety and toxicity of a novel synthetic biopolymer to be used as a patch to treat rhegmatogenous retinal detachment. Methods Thirty one adult wild type albino mice were divided in 2 groups. In Group A (n=9) 0.2 μl balanced salt solution (BSS) and in Group B (n=22), 0.2 μl biopolymer was injected in the subretinal space. Trans-scleral subretinal injection was performed in one eye and the fellow eye was used as control. In both groups, in vivo color fundus photography, electroretinogram (ERG), spectral domain optical coherence tomography (SD-OCT) were performed before injection and at days 7 and 14 post-intervention. Histological analysis was performed following euthanization at days 1, 7 and 21 post-injection. Results The biopolymer was visualized in the subretinal space in vivo by SD-OCT and post-life by histology up to 1 week after the injection. There were no significant differences in ERG parameters between the two groups at 1 and 2 weeks post-injection. Minimal inflammatory response and loss of photoreceptor cells was only observed in the immediate proximity of the site of scleral perforation, which was similar in both groups. Overall integrity of the outer, inner retina and retinal pigment epithelial (RPE) layers was unaffected by the presence of the biopolymer in the subretinal space. Conclusions Functional and histological evaluation suggests that the synthetic biopolymer is non-inflammatory and non-toxic to the eye. It may represent a safe therapeutic agent in the future, for the treatment of rhegmatogenous retinal detachment. PMID:26744635

  5. Boletus edulis biologically active biopolymers induce cell cycle arrest in human colon adenocarcinoma cells.

    PubMed

    Lemieszek, Marta Kinga; Cardoso, Claudia; Ferreira Milheiro Nunes, Fernando Hermínio; Ramos Novo Amorim de Barros, Ana Isabel; Marques, Guilhermina; Pożarowski, Piotr; Rzeski, Wojciech

    2013-04-25

    The use of biologically active compounds isolated from edible mushrooms against cancer raises global interest. Anticancer properties are mainly attributed to biopolymers including mainly polysaccharides, polysaccharopeptides, polysaccharide proteins, glycoproteins and proteins. In spite of the fact that Boletus edulis is one of the widely occurring and most consumed edible mushrooms, antitumor biopolymers isolated from it have not been exactly defined and studied so far. The present study is an attempt to extend this knowledge on molecular mechanisms of their anticancer action. The mushroom biopolymers (polysaccharides and glycoproteins) were extracted with hot water and purified by anion-exchange chromatography. The antiproliferative activity in human colon adenocarcinoma cells (LS180) was screened by means of MTT and BrdU assays. At the same time fractions' cytotoxicity was examined on the human colon epithelial cells (CCD 841 CoTr) by means of the LDH assay. Flow cytometry and Western blotting were applied to cell cycle analysis and protein expression involved in anticancer activity of the selected biopolymer fraction. In vitro studies have shown that fractions isolated from Boletus edulis were not toxic against normal colon epithelial cells and in the same concentration range elicited a very prominent antiproliferative effect in colon cancer cells. The best results were obtained in the case of the fraction designated as BE3. The tested compound inhibited cancer cell proliferation which was accompanied by cell cycle arrest in the G0/G1-phase. Growth inhibition was associated with modulation of the p16/cyclin D1/CDK4-6/pRb pathway, an aberration of which is a critical step in the development of many human cancers including colon cancer. Our results indicate that a biopolymer BE3 from Boletus edulis possesses anticancer potential and may provide a new therapeutic/preventive option in colon cancer chemoprevention.

  6. Evaluation of biopolymer-modified concrete systems for disposal of cathode ray tube glass.

    PubMed

    Kim, Daeik; Petrisor, loana G; Yen, Teh Fu

    2005-07-01

    Cathode ray tubes (CRTs) from computer monitors and television sets, which contain significantly high percentage of lead (Pb) by weight, represent an enormous and growing hazardous waste problem in the United States and worldwide. As a result, new technologies are needed to cope with current CRT waste stream and increased hazard and build new markets for its recycled components, developing commercially viable concrete composites, as well as minimizing CRT disposal problems. In this study, commercially available biopolymers, such as xanthan gum, guar gum, and chitosan, were used to encapsulate CRT glass waste, reducing the Pb leachability. The biopolymers utilized contain a number of useful functional groups, such as carboxyl (xanthan), hydroxyl (guar), and amino groups (chitosan), which play important roles in binding and stabilizing Pb onto concrete structures. The use of biopolymers in concrete systems can create a stable interpenetrating cross-linking composite that will last for many years. Results from these new composites show 30% higher compressive strength than standard concrete and a sharp decrease in lead leachability from several thousand milligrams per liter initially to an amount of three-tenths milligrams per liter or lower values (much lower than the U.S. Environment Protection Agency standard for hazardous waste of 5 mg/L by the toxicity characteristic leaching procedure test), and for some of the composites leachability is below even the standard for drinking water. This efficient and cost-effective CRT-biopolymer-concrete composite is a new class of biopolymer-modified material that can potentially perform a significant role in relieving the current CRT issue.

  7. Coupling a high-temperature catalytic oxidation total organic carbon analyzer to an isotope ratio mass spectrometer to measure natural-abundance delta13C-dissolved organic carbon in marine and freshwater samples.

    PubMed

    Panetta, Robert J; Ibrahim, Mina; Gélinas, Yves

    2008-07-01

    The stable isotope composition of dissolved organic carbon (delta(13)C-DOC) provides powerful information toward understanding carbon sources and cycling, but analytical limitations have precluded its routine measurement in natural samples. Recent interfacing of wet oxidation-based dissolved organic carbon analyzers and isotope ratio mass spectrometers has simplified the measurement of delta(13)C-DOC in freshwaters, but the analysis of salty estuarine/marine samples still proves difficult. Here we describe the coupling of the more widespread high-temperature catalytic oxidation-based total organic carbon analyzer to an isotope ratio mass spectrometer (HTC-IRMS) through cryogenic trapping of analyte gases exiting the HTC analyzer for routine analysis of delta(13)C-DOC in aquatic and marine samples. Targeted elimination of major sources of background CO2 originating from the HTC analyzer allows for the routine measurement of samples over the natural range of DOC concentrations (from 40 microM to over 2000 microM), and salinities (<0.1-36 g/kg). Because consensus reference natural samples for delta(13)C-DOC do not exist, method validation was carried out with water-soluble stable isotope standards as well as previously measured natural samples (IAEA sucrose, Suwannee River Fulvic Acids, Deep Sargasso Sea consensus reference material, and St. Lawrence River water) and result in excellent delta(13)C-DOC accuracy (+/-0.2 per thousand) and precision (+/-0.3 per thousand).

  8. 2013-2014 Production of guayule natural rubber in Arizona, U.S.A.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural rubber is a unique biopolymer whose physical properties cannot be replicated in synthetic alternatives; therefore, it is required for production of tires (passenger, truck, and aircraft) and thousands of consumer and medical products. While demand for natural rubber is expected to increase ...

  9. Observing chemical abundances in comets

    NASA Technical Reports Server (NTRS)

    Delsemme, A. H.

    1981-01-01

    The atomic resonance lines of the major elements were observed in the atmospheres of a few comets, by using vacuum ultraviolet spectrographs on board rockets or orbiting observatories. Dust-to-gas ratios were also deduced for two comets through a Finson-Probstein's analysis of their dust-tail isophotes. The geometric albedo of the dust for the phase angle alpha of the observations is not accurately known but, the dust-to-gas ratio is not overly sensitive to the actual value of this albedo. Infrared observations of the dust head of some comets show that the bulk of cometary dust must be silicates, although a minor component (5-10 percent) of carbon compounds is rather likely, because of poor dielectric properties of the grains. This interpretation is confirmed by the fact that interplanetary dust probably of cometary origin, that was collected in the stratosphere by NASA-U2 Spacecraft, is chondritic in nature. Metal abundances in the head of a sungrazing comet support the chondritic hypothesis.

  10. Measuring Solar Abundances with Seismology

    NASA Astrophysics Data System (ADS)

    Mussack, K.; Gough, D.

    2009-12-01

    The revision of the photospheric abundances proferred by Asplund et al. (2005) has rendered opacity theory inconsistent with the seismologically determined opacity through the Sun. This highlights the need for a direct seismological measurement of solar abundances. Here we describe the technique used to measure abundances with seismology, examine our ability to detect differences between solar models using this technique, and discuss its application in the Sun.

  11. A CRADLE TO GATE LIFE CYCLE ANALYSIS OF THE BIOPOLYMER POLYLACTIC ACID: LOOKING BEYOND GLOBAL WARMING AND FOSSIL FUEL USE

    EPA Science Inventory

    Derived from corn, the biopolymer polylactic acid (PLA) has recently emerged in the marketplace and is advertised as a sustainable alternative to petroleum-based polymers. Research into the environmental implications of biobased production has focused primarily on global warming...

  12. Biopolymer as an Alternative to Petroleum-based Polymers to Control Soil Erosion: Iowa Army Ammunition Plant

    DTIC Science & Technology

    2013-11-01

    increased overall drought tolerance . In summary, the treatability study on the use of biopolymer amendment to improve slope stability of bermed soil and...technology. The R. tropici bacteria are not added to the soil, just the processed biopolymer they produce. End users for the technology are installations...around roots, and nutrient accumulation (Laspidou and Rittmann, 2002). The secretion of EPS by bacteria is recognized as a cohesive force in promoting

  13. Heavy element abundances and massive star formation

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Silk, Joseph

    1993-01-01

    The determination of the stellar initial mass function (IMF) remains a great challenge in astronomy. In the solar neighborhood, the IMF is reasonable well determined for stellar masses from about 0.1 to 60 solar mass. However, outside the solar neighborhood, the IMF is poorly known. Among those frequently discussed arguments favoring a different IMF outside the solar neighborhood are the estimated time to consume the remaining gas in spiral galaxies, and the high rate of forming massive stars in starburst galaxies. An interesting question then is whether there may be an independent way of testing possible variations in the IMF. Indeed, the heavy elements in the interstellar medium are mostly synthesized in massive stars, so increasing, or decreasing, the fraction of massive stars naturally leads to a variation in the heavy element yield, and thus, the metallicity. The observed abundance should severely constrain any deviations of the IMF from the locally determined IMF. We focus on element oxygen, which is the most abundant heavy element in the interstellar medium. Oxygen is ejected only by massive stars that can become Type 1 supernovae, and the oxygen abundance is, therefore, a sensitive function of the fraction of massive stars in the IMF. Adopting oxygen enables us to avoid uncertainties in Type 1 supernovae. We use the nucleosynthesis results to calculate the oxygen yield for given IMF. We then calculate the oxygen abundance in the interstellar medium assuming instantaneous recycling of oxygen.

  14. Type III secretion as a generalizable strategy for the production of full-length biopolymer-forming proteins.

    PubMed

    Azam, Anum; Li, Cheng; Metcalf, Kevin J; Tullman-Ercek, Danielle

    2016-11-01

    Biopolymer-forming proteins are integral in the development of customizable biomaterials, but recombinant expression of these proteins is challenging. In particular, biopolymer-forming proteins have repetitive, glycine-rich domains and, like many heterologously expressed proteins, are prone to incomplete translation, aggregation, and proteolytic degradation in the production host. This necessitates tailored purification processes to isolate each full-length protein of interest from the truncated forms as well as other contaminating proteins; owing to the repetitive nature of these proteins, the truncated polypeptides can have very similar chemistry to the full-length form and are difficult to separate from the full-length protein. We hypothesized that bacterial expression and secretion would be a promising alternative option for biomaterials-forming proteins, simplifying isolation of the full-length target protein. By using a selective secretion system, truncated forms of the protein are not secreted and thus are not found in the culture harvest. We show that a synthetically upregulated type III secretion system leads to a general increase in secretion titer for each protein that we tested. Moreover, we observe a substantial enhancement in the homogeneity of full-length forms of pro-resilin, tropo-elastin crosslinking domains, and silk proteins produced in this manner, as compared with proteins purified from the cytosol. Secretion via the type III apparatus limits co-purification of truncated forms of the target protein and increases protein purity without extensive purification steps. Demonstrating the utility of such a system, we introduce several modifications to resilin-based peptides and use an un-optimized, single-column process to purify these proteins. The resulting materials are of sufficiently high quantity and yield for the production of antimicrobial hydrogels with highly reproducible rheological properties. The ease of this process and its

  15. PALS: A unique probe for the molecular organisation of biopolymer matrices

    NASA Astrophysics Data System (ADS)

    Roussenova, M.; Alam, M. A.

    2013-06-01

    This short review aims to illustrate the versatility of Positron Annihilation Lifetime Spectroscopy (PALS) when utilized for the characterization of biopolymers (e.g.: starch, fractionated maltooligomers, gelatin and cellulose derivatives) commonly used for the formulation of pharmaceutical encapsulants. By showing examples from a number of recent PALS studies, we illustrate that this technique can be used to probe the changes in thermodynamic state and molecular packing for a wide range of biopolymer matrices as a function of temperature, matrix composition and water content. This provides a basis for establishing composition-structure-property relationships for these materials, which would eventually enable the rational control of their macroscopic properties and the design of optimal encapsulating matrices and intelligent drug delivery systems.

  16. Development of Budesonide Loaded Biopolymer Based Dry Powder Inhaler: Optimization, In Vitro Deposition, and Cytotoxicity Study

    PubMed Central

    Mali, Ashwin J.; Pawar, Atmaram P.; Purohit, Ravindra N.

    2014-01-01

    The progress in the development of DPI technology has boosted the use of sensitive drug molecules for lung diseases. However, delivery of these molecules from conventional DPI to the active site still poses a challenge with respect to deposition efficiency in the lung. At same time, serious systemic side effects of drugs have become a cause for concern. The developed budesonide loaded biopolymer based controlled release DPI had shown maximum in vitro lung deposition with least toxicity. The subject of present study, lactose-free budesonide loaded biopolymer based DPI, further corroborates the great potential of antiasthmatic drugs. This technology is expected to revolutionize the approaches towards enhanced therapeutic delivery of prospective drugs. PMID:26556201

  17. Nanofoaming in the surface of biopolymers by femtosecond pulsed laser irradiation

    NASA Astrophysics Data System (ADS)

    Gaspard, S.; Oujja, M.; de Nalda, R.; Abrusci, C.; Catalina, F.; Bañares, L.; Lazare, S.; Castillejo, M.

    2007-12-01

    In this work, the nanostructuring induced in femtosecond (fs) laser irradiation of biopolymers is examined in self-standing films of collagen and gelatine. Irradiation by single 90 fs pulses at 800, 400 and 266 nm is shown to result in the formation of a modified layer with submicrometric size structures. The size and uniformity of the observed features are strongly dependent on irradiation wavelength and on the characteristics of the biopolymer (water content and mechanical strength). Examination of the films by laser induced fluorescence serves to assess the chemical modifications induced by laser irradiation, revealing changes in the emission bands assigned to the aromatic amino acid tyrosine and its degradation products. The results are discussed in the framework of a mechanism involving the generation of large free-electron densities, through multiphoton and avalanche ionization, which determine the temperature and stress distribution in the irradiated volume.

  18. Microfluidic partition with in situ biofabricated semipermeable biopolymer membranes for static gradient generation.

    PubMed

    Luo, Xiaolong; Vo, Thanh; Jambi, Fahad; Pham, Phu; Choy, John S

    2016-09-21

    We report an in situ biofabrication strategy that conveniently partitions microfluidic networks into physically separated while chemically communicating microchannels with semipermeable biopolymer membranes, which enable the facile generation of static gradients for biomedical applications. The biofabrication of parallel biopolymer membranes was initiated with the dissipation of trapped air bubbles in parallel apertures in polydimethylsiloxane (PDMS) microfluidic devices, followed by tunable membrane growth with precise temporal and spatial control to the desired thickness. Static gradients were generated within minutes and well maintained over time by pure diffusion of molecules through the biofabricated semipermeable membranes. As an example application, the static gradient of alpha factor was generated to study the development of the "shmoo" morphology of yeast over time. The in situ biofabrication provides a simple approach to generate static gradients and an ideal platform for biological applications where flow-free static gradients are indispensable.

  19. Looping probability of random heteropolymers helps to understand the scaling properties of biopolymers

    NASA Astrophysics Data System (ADS)

    Zhan, Y.; Giorgetti, L.; Tiana, G.

    2016-09-01

    Random heteropolymers are a minimal description of biopolymers and can provide a theoretical framework to the investigate the formation of loops in biophysical experiments. The looping probability as a function of polymer length was observed to display in some biopolymers, like chromosomes in cell nuclei or long RNA chains, anomalous scaling exponents. Combining a two-state model with self-adjusting simulated-tempering calculations, we calculate numerically the looping properties of several realizations of the random interactions within the chain. We find a continuous set of exponents upon varying the temperature, which arises from finite-size effects and is amplified by the disorder of the interactions. We suggest that this could provide a simple explanation for the anomalous scaling exponents found in experiments. In addition, our results have important implications notably for the study of chromosome folding as they show that scaling exponents cannot be the sole criteria for testing hypothesis-driven models of chromosome architecture.

  20. Preserving the Sequence of a Biopolymer's Monomers as They Enter an Electrospray Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Maulbetsch, William; Wiener, Benjamin; Poole, William; Bush, Joseph; Stein, Derek

    2016-11-01

    This paper investigates how faithfully an electrospray mass spectrometer reports the order of monomers of a single biopolymer in the context of two sequencing strategies. We develop a simplified one-dimensional theoretical model of the dynamics of Brownian particles in the Taylor cone of an electropray source, where free monomers drift towards the apex in an elongational force gradient. The likelihood that neighboring particles will invert their order decreases near the apex because the strength of the force gradient increases. Neighboring monomers on a stretched biopolymer should be cleaved by photofragmentation within about 3 nm of the apex if they are to enter the mass spectrometer in sequence with 95% probability under typical experimental conditions. Alternatively, if the monomers are cleaved processively at milliseconds-long intervals by an enzyme, their sequence will be faithfully reported with 95% confidence if the enzyme is within about 117 nm of the apex.

  1. Effect of disorder on the contact probability of elongated conformations of biopolymers.

    PubMed

    Tiana, Guido

    2015-07-01

    Biopolymers are characterized by heterogeneous interactions, and usually perform their biological tasks forming contacts within domains of limited size. Combining polymer theory with a replica approach, we study the scaling properties of the probability of contact formation in random heteropolymers as a function of their linear distance. It is found that, close to or above the θ point, it is possible to define a contact probability which is typical (i.e., "self-averaging") for different realizations of the heterogeneous interactions, and which displays an exponential cutoff, dependent on temperature and on the interaction range. In many cases this cutoff is comparable with the typical sizes of domains in biopolymers. While it is well known that disorder causes interesting effects at low temperature, the behavior elucidated in the present study is an example of a nontrivial effect at high temperature.

  2. Studies of antibacterial efficacy of different biopolymer protected silver nanoparticles synthesized under reflux condition

    NASA Astrophysics Data System (ADS)

    Su, Chia Hung; Velusamy, Palaniyandi; Kumar, Govindarajan Venkat; Adhikary, Shritama; Pandian, Kannaiyan; Anbu, Periyasamy

    2017-01-01

    In the present study, a simple method to impregnate silver nanoparticles (AgNPs) into carboxymethyl cellulose (CMC) and sodium alginate (SA) is reported for the first time. Single step synthesis of carboxymethyl cellulose (CMC) and sodium alginate (SA) biopolymer protected silver nanoparticles (AgNPs) using aniline as a reducing agent under reflux conditions was investigated. The synthesized nanoparticles were characterized by UV-Vis spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The FESEM results of CMC@AgNPs and SA@AgNPs showed the formation of spherical nanoparticles sized 30-60 nm. Testing of the antibiofilm efficacy of the polymer protected AgNPs against different bacterial strains such as Klebsiella pneumoniae MTCC 4032 and Streptococcus pyogenes MTCC 1924 revealed that the biopolymer protected AgNPs had excellent antibiofilm activity.

  3. Four-photon microwave laser spectroscopy of molecules in the hydration layers of biopolymers and nanoparticles

    SciTech Connect

    Bunkin, Aleksei F; Pershin, Sergei M

    2009-07-31

    Four-photon laser scattering spectra of bidistilled water and aqueous solutions of biopolymers (proteins and DNA), carbon nanotubes and hydrogen peroxide have been measured in the range {+-}10 cm{sup -1}. The spectra show rotational resonances of H{sub 2}O{sub 2}, ortho-H{sub 2}O and para-H{sub 2}O molecules. The resonance contribution of the H{sub 2}O rotational spectrum to the four-photon scattering signal in the solutions of the biopolymers and hydrophobic nanoparticles is an order of magnitude larger in comparison with water, which points to free rotation of the water molecules near the surface of such particles. This effect is due to the formation of water depletion layers near hydrophobic nanoparticles, as predicted in earlier theoretical studies. (special issue devoted to the 80th birthday of S.A. Akhmanov)

  4. Stereolithographic models of the solvent-accessible surface of biopolymers. Topical report

    SciTech Connect

    Bradford, J.; Noel, P.; Emery, J.D.

    1996-11-01

    The solvent-accessible surfaces of several biopolymers were calculated. As part of the DOE education outreach activity, two high school students participated in this project. Computer files containing sets of triangles were produced. These files are called stl files and are the ISO 9001 standard. They have been written onto CD-ROMs for distribution to American companies. Stereolithographic models were made of some of them to ensure that the computer calculations were done correctly. Stereolithographic models were made of interleukin 1{beta} (IL-1{beta}), three antibodies (an anti-p-azobenzene arsonate, an anti-Brucella A cell wall polysaccharide, and an HIV neutralizing antibody), a triple stranded coiled coil, and an engrailed homeodomain. Also, the biopolymers and their files are described.

  5. Nuclear-Shell Biopolymers Initiated by Telomere Elongation for Individual Cancer Cell Imaging and Drug Delivery.

    PubMed

    Zhang, Zhen; Jiao, Yuting; Zhu, Mengting; Zhang, Shusheng

    2017-04-04

    Here, we propose a strategy for unique nuclear-shell biopolymers initiated by telomere elongation for telomerase activity detection and precise drug delivery to individual cancer cells. Telomerase-triggered DNA rolling-circle amplification (RCA) is used to assemble nuclear-shell biopolymers with signal molecules for selective cancer cell recognition and efficient drug delivery to targeted individual cells. This strategy not only should allow the creation of clustered 5-carboxyfluorescein (FAM)-fluorescence spots in response to human-telomerase activity in individual cancer cells but also could efficiently deliver drugs to reduce the undesired death of healthy cells. These findings offer new opportunities to improve the efficacy of cancer cell imaging and therapy.

  6. Composite biodegradable biopolymer coatings of silk fibroin - Poly(3-hydroxybutyric-acid-co-3-hydroxyvaleric-acid) for biomedical applications

    NASA Astrophysics Data System (ADS)

    Miroiu, Floralice Marimona; Stefan, Nicolaie; Visan, Anita Ioana; Nita, Cristina; Luculescu, Catalin Romeo; Rasoga, Oana; Socol, Marcela; Zgura, Irina; Cristescu, Rodica; Craciun, Doina; Socol, Gabriel

    2015-11-01

    Composite silk fibroin-poly(3-hydroxybutyric-acid-co-3-hydroxyvaleric-acid) (SF-PHBV) biodegradable coatings were grown by Matrix Assisted Pulsed Laser Evaporation on titanium substrates. Their physico-chemical properties and particularly the degradation behavior in simulated body fluid at 37 °C were studied as first step of applicability in local controlled release for tissue regeneration applications. SF and PHBV, natural biopolymers with excellent biocompatibility, but different biodegradability and tensile strength properties, were combined in a composite to improve their properties as coatings for biomedical uses. FTIR analyses showed the stoichiometric transfer from targets to coatings by the presence in the spectra of the main absorption maxima characteristic of both polymers. XRD investigations confirmed the FTIR results showing differences in crystallization behavior with respect to the SF and PHBV content. Contact angle values obtained through wettability measurements indicated the MAPLE deposited coatings were highly hydrophilic; surfaces turning hydrophobic with the increase of the PHBV component. Degradation assays proved that higher PHBV contents resulted in enhanced resistance and a slower degradation rate of composite coatings in SBF. Distinct drug-release schemes could be obtained by adjusting the SF:PHBV ratio to controllably tuning the coatings degradation rate, from rapid-release formulas, where SF predominates, to prolonged sustained ones, for larger PHBV content.

  7. Structural and Ionic Transport Properties of Protonic Conducting Solid Biopolymer Electrolytes Based on Carboxymethyl Cellulose Doped with Ammonium Fluoride.

    PubMed

    Ramlli, M A; Isa, M I N

    2016-11-10

    Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and transference number measurement (TNM) techniques were applied to investigate the complexation, structural, and ionic transport properties of and the dominant charge-carrier species in a solid biopolymer electrolyte (SBE) system based on carboxymethyl cellulose (CMC) doped with ammonium fluoride (NH4F), which was prepared via a solution casting technique. The SBEs were partially opaque in appearance, with no phase separation. The presence of interactions between the host polymer (CMC) and the ionic dopant (NH4F) was proven by FT-IR analysis at the C-O band. XRD spectra analyzed using Origin 8 software disclose that the degree of crystallinity (χc%) of the SBEs decreased with the addition of NH4F, indicating an increase in the amorphous nature of the SBEs. Analysis of the ionic transport properties reveals that the ionic conductivity of the SBEs is dependent on the ionic mobility (μ) and diffusion of ions (D). TNM analysis confirms that the SBEs are proton conductors.

  8. The features of infrared spectrum of bio-polymer and its theoretical investigation

    NASA Astrophysics Data System (ADS)

    Pang, Xiao-Feng

    2015-12-01

    We have here an insight into the features of molecular structures of bio-polymers with α-helix structure using infrared spectrum and elucidated theoretically, its relationship with bio-functions. In this case, we analyzed first the features of molecular structure of collagen and collected further the infrared spectrum of absorption of collagen and bovine serum albumin containing α-helix conformation in 400-4000 cm-1 as well as their changes of strength of infrared absorption with varying temperatures using Fourier Transform-Infrared (FT-IR) spectrometers in the region of 15-95°C. The results show that there is a new band of 1650 cm-1 close to the amide-I band of 1666 cm-1 or 1670 cm-1 in these bio-polymers, its strength decreases exponentially with increasing temperature of the systems, which can be expressed by exp[-(0.437 + 8.987 × 10-6 T2)], but 1666 cm-1 band increases linearly with increasing temperature. We calculated the energy spectrum of the protein molecules with α-helix conformation using the Soliton Theory of bio-energy transport, which are basically same with the experimental results measured by us. From these results and soliton theory we can conclude that the nonlinear soliton excitation, corresponding to 1650 cm-1 band and the exciton excitation, is related to 1666 cm-1 band, exists in the collagen and bovine serum albumin. In the meanwhile, these results also verified that the soliton theory of bio-energy transport along α-helix bio-polymers is appropriate to the protein molecules with α-helix conformation. Therefore, the studied results are helpful to elucidate the relationship between the molecular structure and bio-function of these bio-polymers.

  9. Wetting of biopolymer coatings: contact angle kinetics and image analysis investigation.

    PubMed

    Farris, Stefano; Introzzi, Laura; Biagioni, Paolo; Holz, Torsten; Schiraldi, Alberto; Piergiovanni, Luciano

    2011-06-21

    The surface wetting of five biopolymers, used as coating materials for a plastic film, was monitored over a span of 8 min by means of the optical contact angle technique. Because most of the total variation was observed to occur during the first 60 s, we decided to focus on this curtailed temporal window. Initial contact angle values (θ(0)) ranged from ∼91° for chitosan to ∼30° for pullulan. However, the water drop profile began to change immediately following drop deposition for all biocoatings, confirming that the concept of water contact angle equilibrium is not applicable to most biopolymers. First, a three-parameter decay equation [θ(t) = θ(0) exp(kt(n))] was fit to the experimental contact angle data to describe the kinetics of the contact angle change for each biocoating. Interestingly, the k constant correlated well with the contact angle evolution rate and the n exponent seemed to be somehow linked to the physicochemical phenomena underlying the overall kinetics process. Second, to achieve a reliable description of droplet evolution, the contact angle (CA) analysis was coupled with image analysis (IA) through a combined geometric/trigonometric approach. Absorption and spreading were the key factors governing the overall mechanism of surface wetting during the 60 s analysis, although the individual quantification of both phenomena demonstrated that spreading provided the largest contribution for all biopolymers, with the only exception of gelatin, which showed two quasi-equivalent and counterbalancing effects. The possible correlation between these two phenomena and the topography of the biopolymer surfaces are then discussed on the basis of atomic force microscopy analyses.

  10. Biopolymers production with carbon source from the wastes of a beer brewery industry

    NASA Astrophysics Data System (ADS)

    Wong, Phoeby Ai Ling

    The main purpose of this study was to assess the potential and feasibility of malt wastes, and other food wastes, such as soy wastes, ice-cream wastes, confectionery wastes, vinegar wastes, milk waste and sesame oil, in the induction of biosynthesis of PHA, in the cellular assembly of novel PHA with improved physical and chemical properties, and in the reduction of the cost of PHA production. In the first part of the experiments, a specific culture of Alcaligenes latus DSM 1124 was selected to ferment several types of food wastes as carbon sources into biopolymers. In addition, the biopolymer production, by way of using malt waste, of microorganisms from municipal activated sludge was also investigated. In the second part, the experiments focused on the synthesis of biopolymer with a higher molecular mass via the bacterial strain, which was selected and isolated from sesame oil, identified as Staphylococcus epidermidis . Molecular weight and molecular weight distribution of PHB were studied by GPC. Molecular weight of PHB produced from various types of food wastes by Alcaligenes latus was higher than using synthetic sucrose medium as nutrient, however, it resulted in the reverse by Staphylococcus epidermidis. Thermal properties of biopolymers were studied by DSC and TG. Using malt wastes as nutrients by Alcaligenes latus gave a higher melting temperature. Using sucrose, confectionery and sesame oil as nutrients by Staphylococcus epidermidis gave higher melting temperature. Optimization was carried out for the recovery of microbial PHB from Alcaligenes latus. Results showed that molecular weight can be controlled by changing the hypochlorite concentration, the ratio of chloroform to hypochlorite solution and the extraction time. In addition, the determination of PHB content by thermogravimetric analysis method with wet cell was the first report in our study. (Abstract shortened by UMI.)

  11. Nucleosynthesis: Stellar and Solar Abundances and Atomic Data

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Lawler, James E.; Sneden, Christopher; DenHartog, E. A.; Collier, Jason; Dodge, Homer L.

    2006-01-01

    Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy the progenitors of the halo stars responsible for neutron-capture synthesis. Comparisons of abundance trends can be used to understand the chemical evolution of the Galaxy and the nature of heavy element nucleosynthesis. In addition age determinations, based upon long-lived radioactive nuclei abundances, can now be obtained. These stellar abundance determinations depend critically upon atomic data. Improved laboratory transition probabilities have been recently obtained for a number of elements. These new gf values have been used to greatly refine the abundances of neutron-capture elemental abundances in the solar photosphere and in very metal-poor Galactic halo stars. The newly determined stellar abundances are surprisingly consistent with a (relative) Solar System r-process pattern, and are also consistent with abundance predictions expected from such neutron-capture nucleosynthesis.

  12. Implications of Abundant Gas and Oil for Climate Forcing

    NASA Astrophysics Data System (ADS)

    Edmonds, J.

    2015-12-01

    Perhaps the most important development in the field of energy over the past decade has been the advent of technologies that enable the production of larger volumes of natural gas and oil at lower cost. The availability of more abundant gas and oil is reshaping the global energy system, with implications for both evolving emissions of CO2 and other climate forcers. More abundant gas and oil will also transform the character of greenhouse gas emissions mitigation. We review recent findings regarding the impact of abundant gas and oil for climate forcing and the challenge of emissions mitigation. We find strong evidence that, absent policies to limits its penetration against renewable energy, abundant gas has little observable impact on CO2 emissions, and tends to increase overall climate forcing, though the latter finding is subject to substantial uncertainty. The presence of abundant gas also affects emissions mitigation. There is relatively little literature exploring the implication of expanded gas availability on the difficulty in meeting emissions mitigation goals. However, preliminary results indicate that on global scales abundant gas does not substantially affect the cost of emissions mitigation, even though natural gas could have an expanded role in emissions mitigation scenarios as compared with scenarios in which natural gas is less abundant.

  13. Hydration water dynamics in biopolymers from NMR relaxation in the rotating frame

    NASA Astrophysics Data System (ADS)

    Blicharska, Barbara; Peemoeller, Hartwig; Witek, Magdalena

    2010-12-01

    Assuming dipole-dipole interaction as the dominant relaxation mechanism of protons of water molecules adsorbed onto macromolecule (biopolymer) surfaces we have been able to model the dependences of relaxation rates on temperature and frequency. For adsorbed water molecules the correlation times are of the order of 10 -5 s, for which the dispersion region of spin-lattice relaxation rates in the rotating frame R1ρ = 1/ T1ρ appears over a range of easily accessible B1 values. Measurements of T1ρ at constant temperature and different B1 values then give the "dispersion profiles" for biopolymers. Fitting a theoretical relaxation model to these profiles allows for the estimation of correlation times. This way of obtaining the correlation time is easier and faster than approaches involving measurements of the temperature dependence of R1 = 1/ T1. The T1ρ dispersion approach, as a tool for molecular dynamics study, has been demonstrated for several hydrated biopolymer systems including crystalline cellulose, starch of different origins (potato, corn, oat, wheat), paper (modern, old) and lyophilized proteins (albumin, lysozyme).

  14. Nanoencapsulation of the Bioactive Compounds of Spirulina with a Microalgal Biopolymer Coating.

    PubMed

    Greque de Morais, Michele; Greque de Morais, Etiele; Vaz, Bruna da Silva; Gonçalves, Carolina Ferrer; Lisboa, Cristiane; Costa, Jorge Alberto Vieira

    2016-01-01

    Microalgae have been studied in biotechnological processes due to the various biocompounds that can be obtained from their biomasses, including pigments, proteins, antioxidants, biopeptides, fatty acids and biopolymers. Microalgae biopolymers are biodegradable materials that present similar characteristics to traditional polymers, with the advantage of being rapidly degraded when discarded. In addition, nanoencapsulation is capable of increasing the availability of bioactive compounds by allowing the release of these biocompounds to occur slowly over time. The use of polymers in the nanoencapsulation of active ingredients can mask the undesired physicochemical properties of the compounds to be encapsulated, thereby enhancing consumer acceptability. This covering also acts as a barrier against several foreign substances that can react with bioactive compounds and reduce their activity. Studies of the development of poly-3-hydroxybutyrate (PHB) nanocapsules from microbial sources are little explored; this review addresses the use of nanotechnology to obtain bioactive compounds coated with biopolymer nanocapsules, both obtained from Spirulina biomasses. These microalgae are Generally Recognized as Safe (GRAS) certified, which guarantees that the biomass can be used to obtain high added value biocompounds, which can be used in human and animal supplementation.

  15. Biopolymers coated superparamagnetic Nickel Ferrites: Enhanced biocompatibility and MR imaging probe for breast cancer

    NASA Astrophysics Data System (ADS)

    Bano, Shazia; Zafar, Tayyaba; Akhtar, Shahnaz; Buzdar, Saeed Ahmed; Waraich, Mustansar Mahmood; Afzal, Muhammad

    2016-11-01

    We report evidence for the promising application of bovine serum albumin (BSA), chitosan (CS) or carboxymethyl cellulose (CMC) coated NiFe2O4 cores for improved biocompatibility and enhanced T2 relaxivity, through a single combinatorial approach. Pure nickel-ferrite nano cores (NFs) successfully synthesized by thermolysis, were immobilize with BSA, CS or CMC layer employing a simple cross linking procedure to avoid any significant influence of these biopolymers on the morphology and crystal structure of the cores. Phase, morphology, magnetic hysteresis and surface chemistry were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM) and Fourier transform infrared (FTIR) spectroscopy. The preliminary haemolysis and cell viability experiments show that biopolymers conjugation mitigates the haemolytic effect of the NFs on erythrocytes as the haemolytic index is less than 2% and cell viability is up to 100%, when normalized with the nontreated cells. The relaxivity value of coated NFs is 351±2.6 when compared to 84±0.22 of NFs without