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Sample records for chitosan improves maize

  1. Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress

    Institute of Scientific and Technical Information of China (English)

    Ya-jing GUAN; Jin HU; Xian-ju WANG; Chen-xia SHAO

    2009-01-01

    Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 ℃ on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60~64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress.

  2. Synergistic Effects of Plant Growth Promoting Rhizobacteria and Chitosan on In Vitro Seeds Germination, Greenhouse Growth, and Nutrient Uptake of Maize (Zea mays L.

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    Nadège A. Agbodjato

    2016-01-01

    Full Text Available This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the control, P. putida has significantly improved root weight (44.84% and germinated seed weight (31.39% whereas chitosan-P. putida has increased the shoot weight (65.67%. For the growth test, the maximal heights (17.66% were obtained by plants treated with the combination A. lipoferum-P. fluorescens-P. putida. Chitosan-P. fluorescens induced the highest increases of leaves per plant (50.09%, aerial (84.66%, and underground biomass (108.77% production. The plants inoculated with A. lipoferum had the large leaf areas with an increase of 54.08%, while combinations P. fluorescens-P. putida and chitosan-A. lipoferum improved the aerial and underground dry matter of plants to 26.35% and 18.18%. The nitrogen content of the plants was increased by chitosan-A. lipoferum-P. fluorescens-P. putida with an increasing of 41.61%. The combination of chitosan and PGPR can be used as biological fertilizers to increase maize production.

  3. ADVANCES IN TRANSGENIC MAIZE FOR QUALITY IMPROVEMENT

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    M.Rajendar Reddy

    2015-12-01

    Full Text Available Maize (Zea mays is a major food and animal feed worldwide and occupies a relevant place in the world economy and trade as an industrial grain crop. Currently more than 70% of maize production is used for food and feed; therefore, knowledge of genes involved in grain structure and chemical is important for improving the nutritional and food-making properties of maize. It is a good source of carbohydrates, fats, proteins, vitamins and minerals but deficient in two essential amino acids, Viz., lysine and tryptophan. To overcome this problem and to improve the above quality characters the maize breeders have followed different strategies like opaque 2, QPM and development of transgenic maize with improved quality characters. Finally we can conclude that the conventional breeding techniques and now plant biotechnology are helping meet the growing demand for food production, nutrition security while preserving our environment for future generations

  4. Comparative population genomics of maize domestication and improvement.

    Science.gov (United States)

    Hufford, Matthew B; Xu, Xun; van Heerwaarden, Joost; Pyhäjärvi, Tanja; Chia, Jer-Ming; Cartwright, Reed A; Elshire, Robert J; Glaubitz, Jeffrey C; Guill, Kate E; Kaeppler, Shawn M; Lai, Jinsheng; Morrell, Peter L; Shannon, Laura M; Song, Chi; Springer, Nathan M; Swanson-Wagner, Ruth A; Tiffin, Peter; Wang, Jun; Zhang, Gengyun; Doebley, John; McMullen, Michael D; Ware, Doreen; Buckler, Edward S; Yang, Shuang; Ross-Ibarra, Jeffrey

    2012-06-03

    Domestication and plant breeding are ongoing 10,000-year-old evolutionary experiments that have radically altered wild species to meet human needs. Maize has undergone a particularly striking transformation. Researchers have sought for decades to identify the genes underlying maize evolution, but these efforts have been limited in scope. Here, we report a comprehensive assessment of the evolution of modern maize based on the genome-wide resequencing of 75 wild, landrace and improved maize lines. We find evidence of recovery of diversity after domestication, likely introgression from wild relatives, and evidence for stronger selection during domestication than improvement. We identify a number of genes with stronger signals of selection than those previously shown to underlie major morphological changes. Finally, through transcriptome-wide analysis of gene expression, we find evidence both consistent with removal of cis-acting variation during maize domestication and improvement and suggestive of modern breeding having increased dominance in expression while targeting highly expressed genes.

  5. Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide: their influence on some phenological and biochemical behaviors

    Science.gov (United States)

    Lizárraga-Paulín, Eva-Guadalupe; Miranda-Castro, Susana-Patricia; Moreno-Martínez, Ernesto; Lara-Sagahón, Alma-Virginia; Torres-Pacheco, Irineo

    2013-01-01

    Objective: To evaluate the effect of chitosan (CH) and hydrogen peroxide (H2O2) seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology, the H2O2 presence, the catalase (CAT) activity, and the protein quantity. Methods: Seven groups of ten seeds for each maize variety were treated with CH (2% (20 g/L) and 0.2% (2 g/L)) or H2O2 (8 mmol/L) by coating, sprinkling, or both. Germination and seedling growth were measured. One month after germination, the presence of H2O2 in seedlings in the coated seed treatments was evaluated. Protein content and CAT activity were determined under all treatments. Results: H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize (QPM) variety. Seedlings had a higher emergence velocity under this treatment in both varieties. CH and H2O2 sprinklings did not have an effect on seedling phenology. Exogenous application of H2O2 promoted an increase of endogenous H2O2. CH and H2O2 seedling sprinkling increased the protein content in both maize varieties, while there was no significant effect on the CAT activity of treated seeds and seedlings. Conclusions: CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application. PMID:23365007

  6. Silicon Improves Maize Photosynthesis in Saline-Alkaline Soils

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    Zhiming Xie

    2015-01-01

    Full Text Available The research aimed to determine the effects of Si application on photosynthetic characteristics of maize on saline-alkaline soil, including photosynthetic rate (Pn, stomatal conductance (gs, transpiration rate (E, and intercellular CO2 concentration (Ci of maize in the field with five levels (0, 45, 90, 150, and 225 kg·ha−1 of Si supplying. Experimental results showed that the values of Pn, gs, and Ci of maize were significantly enhanced while the values of E of maize were dramatically decreased by certain doses of silicon fertilizers, which meant that Si application with proper doses significantly increased photosynthetic efficiency of maize in different growth stages under stressing environment of saline-alkaline soil. The optimal dose of Si application in this experiment was 150 kg·ha−1 Si. It indicated that increase in maize photosynthesis under saline-alkaline stress took place by Si application with proper doses, which is helpful to improve growth and yield of maize.

  7. Silicon improves maize photosynthesis in saline-alkaline soils.

    Science.gov (United States)

    Xie, Zhiming; Song, Ri; Shao, Hongbo; Song, Fengbin; Xu, Hongwen; Lu, Yan

    2015-01-01

    The research aimed to determine the effects of Si application on photosynthetic characteristics of maize on saline-alkaline soil, including photosynthetic rate (P n ), stomatal conductance (g s ), transpiration rate (E), and intercellular CO2 concentration (C i ) of maize in the field with five levels (0, 45, 90, 150, and 225 kg · ha(-1)) of Si supplying. Experimental results showed that the values of P n, g s, and C i of maize were significantly enhanced while the values of E of maize were dramatically decreased by certain doses of silicon fertilizers, which meant that Si application with proper doses significantly increased photosynthetic efficiency of maize in different growth stages under stressing environment of saline-alkaline soil. The optimal dose of Si application in this experiment was 150 kg · ha(-1) Si. It indicated that increase in maize photosynthesis under saline-alkaline stress took place by Si application with proper doses, which is helpful to improve growth and yield of maize.

  8. Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide:their influence on some phenological and biochemical behaviors

    Institute of Scientific and Technical Information of China (English)

    Eva-Guadalupe LIZ(A)RRAGA-PAUL(I)N; Susana-Patricia MIRANDA-CASTRO; Ernesto MORENO-MART(I)NEZ; Alma-Virginia LARA-SAGAH(O)N; Irineo TORRES-PACHECO

    2013-01-01

    Objective:To evaluate the effect of chitosan(CH)and hydrogen peroxide(H2O2)seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology,the H2O2 presence,the catalase (CAT)activity,and the protein quantity.Methods:Seven groups of ten seeds for each maize variety were treated with CH(2%(20 g/L)and 0.2%(2 g/L))or H2O2(8 mmol/L)by coating,sprinkling,or both.Germination and seedling growth were measured.One month after germination,the presence of H2O2 in seedlings in the coated seed treatments was evaluated.Protein content and CAT activity were determined under all treatments.Results:H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize(QPM)variety.Seedlings had a higher emergence velocity under this treatment in both varieties.CH and H2O2 sprinklings did not have an effect on seedling phenology.Exogenous application of H2O2 promoted an increase of endogenous H2O2.CH and H2O2 seedling sprinkling increased the protein content in both maize varieties,while there was no significant effect on the CAT activity of treated seeds and seedlings.Conclusions:CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application.

  9. Combined effect of chitosan and water activity on growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on maize-based media.

    Science.gov (United States)

    Ferrochio, Laura V; Cendoya, Eugenia; Zachetti, Vanessa G L; Farnochi, Maria C; Massad, Walter; Ramirez, Maria L

    2014-08-18

    The objectives of the present study were to determine the in vitro efficacy of chitosan (0.5, 1.0, 2.0 and 3.0mg/mL) under different water availabilities (0.995, 0.99, 0.98, 0.96 and 0.93) at 25°C on lag phase, growth rate and fumonisin production by isolates of Fusarium verticillioides and Fusarium proliferatum. The presence of chitosan affected growth and fumonisin production, and this effect was dependent on the dose and aW treatment used. The presence of chitosan increased the lag phase, and reduced the growth rate of both Fusarium species significantly at all concentrations used, especially at 0.93 aW. Also, significant reduction of fumonisin production was observed in both Fusarium species at all conditions assayed. The present study has shown the combined effects of chitosan and aW on growth and fumonisin production by the two most important Fusarium species present on maize. Low molecular weight (Mw) chitosan with more than 70% of degree of deacetylation (DD) at 0.5mg/mL was able to significantly reduce growth rate and fumonisin production on maize-based media, with maximum levels of reduction in both parameters obtained at the highest doses used. As fumonisins are unavoidable contaminants in food and feed chains, their presence needs to be reduced to minimize their effects on human and animal health and to diminish the annual market loss through rejected maize. In this scenario post-harvest use of chitosan could be an important alternative treatment.

  10. Using chitosan as a thickener for electrospinning dilute PVA solutions to improve fibre uniformity

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    Lin, Tong; Fang, Jian; Wang, Hongxia; Cheng, Tong; Wang, Xungai

    2006-08-01

    Chitosan was added to PVA aqueous solutions as a thickener to improve the electrospinning process. The presence of a small amount of chitosan considerably improved the uniformity of as-spun nanofibres. This improvement is attributed to its significant effect on the solution viscosity and conductivity, with only a slight impact on the surface tension. The concentration of the PVA required to produce bead-free and uniform nanofibres was reduced with the increase in chitosan concentration. The chitosan thickener suppressed the jet break-up and facilitated the jet stretching so that fine and uniform fibres could be electrospun even from a dilute PVA solution.

  11. Using chitosan as a thickener for electrospinning dilute PVA solutions to improve fibre uniformity

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    Lin Tong; Fang Jian; Wang Hongxia; Cheng Tong; Wang Xungai [Centre for Material and Fibre Innovation, Faculty of Science and Technology, Deakin University, Geelong, VIC 3217 (Australia)

    2006-08-14

    Chitosan was added to PVA aqueous solutions as a thickener to improve the electrospinning process. The presence of a small amount of chitosan considerably improved the uniformity of as-spun nanofibres. This improvement is attributed to its significant effect on the solution viscosity and conductivity, with only a slight impact on the surface tension. The concentration of the PVA required to produce bead-free and uniform nanofibres was reduced with the increase in chitosan concentration. The chitosan thickener suppressed the jet break-up and facilitated the jet stretching so that fine and uniform fibres could be electrospun even from a dilute PVA solution.

  12. Impact of Improved Maize Adoption on Welfare of Farm Households in Malawi: A Panel Data Analysis

    OpenAIRE

    Bezu, Sosina; Kassie, Girma; Shiferaw, Bekele; Ricker-Gilbert, Jacob

    2013-01-01

    This paper assesses improved maize adoption in Malawi and examines the link between adoption and household welfare using a three-year household panel data. The distributional effect of maize technology adoption is also investigated by looking at impacts across wealth and gender groups. We applied control function approach and IV regression to control for endogeneity of input subsidy and improved maize adoption. We found that modern maize variety adoption is positively correlated with the hous...

  13. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications.

  14. Genetic characterization of a core set of a tropical maize race Tuxpeno for further use in maize improvement.

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    Weiwei Wen

    Full Text Available The tropical maize race Tuxpeño is a well-known race of Mexican dent germplasm which has greatly contributed to the development of tropical and subtropical maize gene pools. In order to investigate how it could be exploited in future maize improvement, a panel of maize germplasm accessions was assembled and characterized using genome-wide Single Nucleotide Polymorphism (SNP markers. This panel included 321 core accessions of Tuxpeño race from the International Maize and Wheat Improvement Center (CIMMYT germplasm bank collection, 94 CIMMYT maize lines (CMLs and 54 U.S. Germplasm Enhancement of Maize (GEM lines. The panel also included other diverse sources of reference germplasm: 14 U.S. maize landrace accessions, 4 temperate inbred lines from the U.S. and China, and 11 CIMMYT populations (a total of 498 entries with 795 plants. Clustering analyses (CA based on Modified Rogers Distance (MRD clearly partitioned all 498 entries into their corresponding groups. No sub clusters were observed within the Tuxpeño core set. Various breeding strategies for using the Tuxpeño core set, based on grouping of the studied germplasm and genetic distance among them, were discussed. In order to facilitate sampling diversity within the Tuxpeño core, a minicore subset of 64 Tuxpeño accessions (20% of its usual size representing the diversity of the core set was developed, using an approach combining phenotypic and molecular data. Untapped diversity represents further use of the Tuxpeño landrace for maize improvement through the core and/or minicore subset available to the maize community.

  15. Cross-linked chitosan improves the mechanical properties of calcium phosphate-chitosan cement.

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    Aryaei, Ashkan; Liu, Jason; Jayatissa, Ahalapitiya H; Jayasuriya, A Champa

    2015-09-01

    Calcium phosphate (CaP) cements are highly applicable and valuable materials for filling bone defects by minimally invasive procedures. The chitosan (CS) biopolymer is also considered as one of the promising biomaterial candidates in bone tissue engineering. In the present study, some key features of CaP-CS were significantly improved by developing a novel CaP-CS composite. For this purpose, CS was the first cross-linked with tripolyphosphate (TPP) and then mixed with CaP matrix. A group of CaP-CS samples without cross-linking was also prepared. Samples were fabricated and tested based on the known standards. Additionally, the effect of different powder (P) to liquid (L) ratios was also investigated. Both cross-linked and uncross-linked CaP-CS samples showed excellent washout resistance. The most significant effects were observed on Young's modulus and compressive strength in wet condition as well as surface hardness. In dry conditions, the Young's modulus of cross-linked samples was slightly improved. Based on the presented results, cross-linking does not have a significant effect on porosity. As expected, by increasing the P/L ratio of a sample, ductility and injectability were decreased. However, in the most cases, mechanical properties were enhanced. The results have shown that cross-linking can improve the mechanical properties of CaP-CS and hence it can be used for bone tissue engineering applications.

  16. Improved mechanical properties of chitosan fibers with applications to degradable radar countermeasure chaff

    Science.gov (United States)

    Knaul, Jonathan Zvi

    The objective of this work has been to improve the mechanical properties of wet spun chitosan fibers for applications to a degradable form of radar countermeasure chaff. The first part of the study characterizes the chitosan used for spinning. Three methods for determining the degree of deacetylation (% DDA) were used and they include titration, elemental analysis, and first derivative ultraviolet (UV) spectrometry. The molecular weight of the chitosan was determined in a solvent system of 0.25 M CH3COOH/0.25 M CH3COONa, using viscometry and gel permeation chromatography (GPC). Several samples of chitosan were used with the % DDA varying from 64.3 to 96.0%. The Mark-Houwink-Sakurada constants used for the determination of viscosity average molecular weight and the universal calibration of the HPLC system were K = 1.40 x 10 -4 dL/g and a = 0.83, respectively. A literature review of molecular weight analysis of chitosan is included. Preliminary wet spinning experiments involved a coagulation rate study which demonstrated that 1 M KOH was an effective coagulant for wet spinning and that the rate of coagulation increases with decreasing solvent ratio in the spin dope. A drying study confirmed the effectiveness of a methanol drying bath followed by a heated roller at 50°C. Following these studies, a wet spinning system was constructed and used. A lack of published data exists concerning the subjects of chitosan fiber spinning and mechanical improvements to both wet and dry chitosan fibers. Several post-spinning modification experiments focused on the reaction of the dried as-spun chitosan fibers with aqueous agents including potassium dihydrogen phosphate (KH2PO4), potassium hydrogen phthalate (KHP), glutaraldehyde (GA), and glyoxal (GLY). For the aqueous buffering agents of KH2PO4, and KHP, the highest mechanical properties resulted from solutions containing phthalate ions at pH 5.00, and from solutions containing phosphate ions at pH 5.39. The best time and

  17. Hydrophobic surface modification of chitosan gels by stearyl for improving the activity of immobilized lipase

    Institute of Scientific and Technical Information of China (English)

    Hong Tao Deng; Juan Juan Wang; Miao Ma; Zhong Yang Liu; Fei Zheng

    2009-01-01

    The hydrophobic surface modification of chitosan gels was carded out using the amidating reaction of amido groups on a gel surface with steafic acid activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxy-succinimide (NHS). Lipases from Candida rugosa were adsorbed on the nascent chitosan gels (CS) and stearyl-modified gels (SCS) with different degrees of amidation. The increased surface hydrophobicity of chitosan gels improved the adsorption capacity and activity of the immobilized lipase. SCS with 31.46% amidation showed the maximum activity retention (83.43%). The experimental results suggest that the moderate surface hydrophilicity/hydropbobicity of chitosan gels is necessary for the improvement of the activity of immobilized lipase.

  18. Comparative analysis of maize (Zea mays) crop performance: natural variation, incremental improvements and economic impacts.

    Science.gov (United States)

    Leibman, Mark; Shryock, Jereme J; Clements, Michael J; Hall, Michael A; Loida, Paul J; McClerren, Amanda L; McKiness, Zoe P; Phillips, Jonathan R; Rice, Elena A; Stark, Steven B

    2014-09-01

    Grain yield from maize hybrids continues to improve through advances in breeding and biotechnology. Despite genetic improvements to hybrid maize, grain yield from distinct maize hybrids is expected to vary across growing locations due to numerous environmental factors. In this study, we examine across-location variation in grain yield among maize hybrids in three case studies. The three case studies examine hybrid improvement through breeding, introduction of an insect protection trait or introduction of a transcription factor trait associated with increased yield. In all cases, grain yield from each hybrid population had a Gaussian distribution. Across-location distributions of grain yield from each hybrid partially overlapped. The hybrid with a higher mean grain yield typically outperformed its comparator at most, but not all, of the growing locations (a 'win rate'). These results suggest that a broad set of environmental factors similarly impacts grain yields from both conventional- and biotechnology-derived maize hybrids and that grain yields among two or more hybrids should be compared with consideration given to both mean yield performance and the frequency of locations at which each hybrid 'wins' against its comparators. From an economic standpoint, growers recognize the value of genetically improved maize hybrids that outperform comparators in the majority of locations. Grower adoption of improved maize hybrids drives increases in average U.S. maize grain yields and contributes significant value to the economy.

  19. Preparation of chitosan films using different neutralizing solutions to improve endothelial cell compatibility.

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    He, Qing; Ao, Qiang; Gong, Yandao; Zhang, Xiufang

    2011-12-01

    The development of chitosan-based constructs for application in large-size defects or highly vascularized tissues is still a challenging issue. The poor endothelial cell compatibility of chitosan hinders the colonization of vascular endothelial cells in the chitosan-based constructs, and retards the establishment of a functional microvascular network following implantation. The aim of the present study is to prepare chitosan films with different neutralization methods to improve their endothelial cell compatibility. Chitosan salt films were neutralized with either sodium hydroxide (NaOH) aqueous solution, NaOH ethanol solution, or ethanol solution without NaOH. The physicochemical properties and endothelial cell compatibility of the chitosan films were investigated. Results indicated that neutralization with different solutions affected the surface chemistry, swelling ratio, crystalline conformation, nanotopography, and mechanical properties of the chitosan films. The NaOH ethanol solution-neutralized chitosan film (Chi-NaOH/EtOH film) displayed a nanofiber-dominant surface, while the NaOH aqueous solution-neutralized film (Chi-NaOH/H(2)O film) and the ethanol solution-neutralized film (Chi-EtOH film) displayed nanoparticle-dominant surfaces. Moreover, the Chi-NaOH/EtOH films exhibited a higher stiffness as compared to the Chi-NaOH/H(2)O and Chi-EtOH films. Endothelial cell compatibility of the chitosan films was evaluated with a human microvascular endothelial cell line, HMEC-1. Compared with the Chi-NaOH/H(2)O and Chi-EtOH films, HMECs cultured on the Chi-NaOH/EtOH films fully spread and exhibited significantly higher levels of adhesion and proliferation, with retention of the endothelial phenotype and function. Our findings suggest that the surface nanotopography and mechanical properties contribute to determining the endothelial cell compatibility of chitosan films. The nature of the neutralizing solutions can affect the physicochemical properties and

  20. Gentamicin modified chitosan film with improved antibacterial property and cell biocompatibility.

    Science.gov (United States)

    Liu, Yang; Ji, Peihong; Lv, Huilin; Qin, Yong; Deng, Linhong

    2017-05-01

    Gentamicin modified chitosan film (CS-GT) was produced using a three-step procedure comprising: (i) the chitosan solution was air-dried to form a chitosan (CS) film, (ii) using citric acid to generate the amide and carboxyl groups on the surface of CS, (iii) the CS with surface carboxyl groups was modified by grafting of gentamicin. After modification, this CS-GT film has excellent hydrophilicity and biocompatibility. It is very evident that the gentamicin grafting treatment significantly improves the antibacterial properties of the CS film. Our preliminary results suggest that this novel gentamicin modified chitosan film, which can be prepared in large quantities and at low cost, should have potential application in biomedical applications.

  1. Silicon Improves Maize Photosynthesis in Saline-Alkaline Soils

    OpenAIRE

    Zhiming Xie; Ri Song; Hongbo Shao; Fengbin Song; Hongwen Xu; Yan Lu

    2015-01-01

    The research aimed to determine the effects of Si application on photosynthetic characteristics of maize on saline-alkaline soil, including photosynthetic rate (P n ), stomatal conductance (g s ), transpiration rate (E), and intercellular CO2 concentration (C i ) of maize in the field with five levels (0, 45, 90, 150, and 225 kg·ha−1) of Si supplying. Experimental results showed that the values of P n , g s , and C i of maize were significantly enhanced while the values of E of maize were dra...

  2. Improvement of HDL- and LDL-cholesterol levels in diabetic subjects by feeding bread containing chitosan.

    Science.gov (United States)

    Ausar, S F; Morcillo, M; León, A E; Ribotta, P D; Masih, R; Vilaro Mainero, M; Amigone, J L; Rubin, G; Lescano, C; Castagna, L F; Beltramo, D M; Diaz, G; Bianco, I D

    2003-01-01

    In this work we evaluated the efficacy and safety of a bread formulation containing chitosan in dyslipidemic type 2 diabetic subjects. For this purpose a total of 18 patients were allowed to incorporate to their habitual diets 120 g/day of bread containing 2% (wt/wt) chitosan (chitosan group, n= 9) or standard bread (control group, n= 9). Before the study and after 12 weeks on the modified diet, the following parameters were evaluated: body weight, plasma cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglyceride, and hemoglobin A(1c) (HbA(1c)). Compared with the control group, the patients receiving chitosan-containing bread decreased their mean levels of LDL-cholesterol and significantly increased their mean levels of HDL-cholesterol at the end of the study. There were no significant differences in the body weight, serum triglyceride, and HbA(1c). These results suggest that chitosan incorporated into bread formulations could improve the lipoprotein balance similar to typical biliary salts trappers, increasing the HDL- and lowering the LDL-cholesterol, without changing the triglyceride levels. These results warrant further studies over a longer period of time to evaluate if a persistent improvement in levels of lipoproteins can be attained with this strategy.

  3. Chitosan improves the biological performance of soy-based biomaterials

    OpenAIRE

    Santos, T. C.; MARQUES, A.P.; SILVA, S. S.; Oliveira, Joaquim M.; Mano, J. F.; Castro, António G.; van Griensven, Martijn; Reis, R. L.

    2010-01-01

    Soybean protein has been proposed for distinct applications within nutritional, pharmaceutical, and cosmetic industries among others. More recently, soy-based biomaterials have also demonstrated promising properties for biomedical applications.However, althoughmany reports within other fields exist, the inflammatory/immunogenic potential of those materials is still poorly understood and therefore can hardly be controlled. On the contrary, chitosan (Cht) has been well explored in t...

  4. Chitosan improves anti-biofilm efficacy of gentamicin through facilitating antibiotic penetration.

    Science.gov (United States)

    Mu, Haibo; Guo, Fan; Niu, Hong; Liu, Qianjin; Wang, Shunchun; Duan, Jinyou

    2014-12-03

    Antibiotic overuse is one of the major drivers in the generation of antibiotic resistant "super bugs" that can potentially cause serious effects on health. In this study, we reported that the polycationic polysaccharide, chitosan could improve the efficacy of a given antibiotic (gentamicin) to combat bacterial biofilms, the universal lifestyle of microbes in the world. Short- or long-term treatment with the mixture of chitosan and gentamicin resulted in the dispersal of Listeria monocytogenes (L. monocytogenes) biofilms. In this combination, chitosan with a moderate molecular mass (~13 kDa) and high N-deacetylation degree (~88% DD) elicited an optimal anti-biofilm and bactericidal activity. Mechanistic insights indicated that chitosan facilitated the entry of gentamicin into the architecture of L. monocytogenes biofilms. Finally, we showed that this combination was also effective in the eradication of biofilms built by two other Listeria species, Listeria welshimeri and Listeria innocua. Thus, our findings pointed out that chitosan supplementation might overcome the resistance of Listeria biofilms to gentamicin, which might be helpful in prevention of gentamicin overuse in case of combating Listeria biofilms when this specific antibiotic was recommended.

  5. Chitosan Improves Anti-Biofilm Efficacy of Gentamicin through Facilitating Antibiotic Penetration

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    Haibo Mu

    2014-12-01

    Full Text Available Antibiotic overuse is one of the major drivers in the generation of antibiotic resistant “super bugs” that can potentially cause serious effects on health. In this study, we reported that the polycationic polysaccharide, chitosan could improve the efficacy of a given antibiotic (gentamicin to combat bacterial biofilms, the universal lifestyle of microbes in the world. Short- or long-term treatment with the mixture of chitosan and gentamicin resulted in the dispersal of Listeria monocytogenes (L. monocytogenes biofilms. In this combination, chitosan with a moderate molecular mass (~13 kDa and high N-deacetylation degree (~88% DD elicited an optimal anti-biofilm and bactericidal activity. Mechanistic insights indicated that chitosan facilitated the entry of gentamicin into the architecture of L. monocytogenes biofilms. Finally, we showed that this combination was also effective in the eradication of biofilms built by two other Listeria species, Listeria welshimeri and Listeria innocua. Thus, our findings pointed out that chitosan supplementation might overcome the resistance of Listeria biofilms to gentamicin, which might be helpful in prevention of gentamicin overuse in case of combating Listeria biofilms when this specific antibiotic was recommended.

  6. Organic/inorganic nanocomposites of ZnO/CuO/chitosan with improved properties

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xingfa, E-mail: xingfamazju@aliyun.com [School of Environmental and Material Engineering, Center of Advanced Functional Materials, Yantai University, Yantai, 264005 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Zhang, Bo; Cong, Qin; He, Xiaochun; Gao, Mingjun [School of Environmental and Material Engineering, Center of Advanced Functional Materials, Yantai University, Yantai, 264005 (China); Li, Guang [National Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou, 310027 (China)

    2016-08-01

    To extend the visible light response of ZnO, ZnO/CuO heterostructured nanocomposite was synthesized by a hydrothermal approach. At the same time, chitosan (Ch) is considered as a very promising natural polymer. It holds not only abundant resource and low cost, but also has excellent adsorption properties to a broad range of organic pollutants and some heavy metal ions. To improve the adsorption properties of ZnO/CuO nanocomposite, ZnO/CuO/chitosan organic-inorganic composites were prepared with precipitation method. The as-prepared nanocomposites were characterized by TEM (Transmission electron microscopy), SAED pattern (Selected Area Electron Diffraction), SEM (scanning electron microscopy), UV–Vis (Ultraviolet–visible spectroscopy), PL (Photoluminescence), XRD (X-ray diffraction), TGA (Thermo Gravimetric Analyzer), Fourier transform infrared spectroscopy spectra (FTIR) et al. To examine the surface and interface properties of nanocomposites, chemical prototype sensor arrays were constructed based on ZnO, ZnO/CuO, ZnO/Cu{sub 2}O, ZnO/CuO/chitosan, ZnO/Cu{sub 2}O/chitosan nanocomposites and QCM (quartz crystal microbalance) arrays devices. The adsorption response behaviors of the sensor arrays to some typical volatile compounds were examined under similar conditions. The results indicated that with comparison to ZnO nanostructure, the ZnO/CuO nanocomposite exhibited enhanced adsorption properties to some typical volatile compounds greatly, and the adsorption properties of ZnO/CuO/chitosan are much better than that of ZnO/CuO nanocomposite. The adsorption of ZnO/CuO system is super to that of ZnO/Cu{sub 2}O. Therefore, ZnO/CuO/chitosan nanocomposite not only showed broadening visible light response, but also possessed of excellent adsorption properties, and has good potential applications in photocatalysts, chemical sensors, biosensors, self-cleaning coating fields et al. - Highlights: • ZnO/CuO nanocomposites exhibited good response in near whole visible

  7. Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves

    Energy Technology Data Exchange (ETDEWEB)

    Gallyamov, Marat O., E-mail: glm@spm.phys.msu.ru [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Chaschin, Ivan S. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Khokhlova, Marina A. [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Grigorev, Timofey E. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Bakuleva, Natalia P.; Lyutova, Irina G.; Kondratenko, Janna E. [Bakulev Scientific Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences, Roublyevskoe Sh. 135, Moscow 121552 (Russian Federation); Badun, Gennadii A.; Chernysheva, Maria G. [Radiochemistry Division, Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Khokhlov, Alexei R. [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation)

    2014-04-01

    Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H{sub 2}O and CO{sub 2}. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16–33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1 wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. - Highlights: • Treatment of GA

  8. Hydrogen sulfide donor sodium hydrosulfide-improved heat tolerance in maize and involvement of proline.

    Science.gov (United States)

    Li, Zhong-Guang; Ding, Xiao-Jiao; Du, Pei-Fang

    2013-05-15

    Hydrogen sulfide (H2S) has long been considered as a phytotoxin, but nowadays as a cell signal molecule involved in growth, development, and the acquisition of stress tolerance in higher plants. In the present study, hydrogen sulfide donor, sodium hydrosulfide (NaHS), pretreatment markedly improved germination percentage of seeds and survival percentage of seedlings of maize under heat stress, and alleviated an increase in electrolyte leakage of roots, a decrease in tissue vitality and an accumulation of malondialdehyde (MDA) in coleoptiles of maize seedlings. In addition, pretreatment of NaHS could improve the activity of Δ(1)-pyrroline-5-carboxylate synthetase (P5CS) and lower proline dehydrogenase (ProDH) activity, which in turn induced accumulation of endogenous proline in maize seedlings. Also, application of proline could enhance endogenous proline content, followed by mitigated accumulation of MDA and increased survival percentage of maize seedlings under heat stress. These results suggest that sodium hydrosulfide pretreatment could improve heat tolerance of maize and the acquisition of this heat tolerance may be involved in proline.

  9. Improvement of cerium of photosynthesis functions of maize under magnesium deficiency.

    Science.gov (United States)

    Zhou, Min; Gong, Xiaolan; Wang, Ying; Liu, Chao; Hong, Mengmeng; Wang, Ling; Hong, Fashui

    2011-09-01

    Rare earth elements can promote photosynthesis, but their mechanisms are still poorly understood under magnesium deficiency. The present study was designed to determine the role of cerium in magnesium-deficient maize plants. Maize was cultivated in Hoagland's solution added with cerium with and without adequate quantities of magnesium. Under magnesium-deficient conditions, cerium can prevents inhibition of synthesis of photosynthetic pigment, improves light energy absorption and conversion, oxygen evolution, and the activity of photo-phosphorelation and its coupling factor Ca(2+)-ATPase. These results suggest that cerium could partly substitute magnesium, improving photosynthesis and plant growth.

  10. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila

    Energy Technology Data Exchange (ETDEWEB)

    Li, T.; Liu, M.J.; Zhang, X.T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhang, H.B. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Department of Biology, Yunnan University, Kunming, 650091 Yunnan (China); Sha, T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhao, Z.W., E-mail: zhaozhw@ynu.edu.cn [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China)

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments. - Research Highlights: {yields}Effect of DSE (E. pisciphila) on heavy metal tolerance of maize host was studied. {yields}DSE alleviated the deleterious effect of excessive heavy metals on maize. {yields}DSE restricted the transfer of heavy metals from the roots to shoots in maize. {yields}DSE colonization improved the tolerance of their host plants to heavy metals.

  11. Insect stings to change gear for healthy plant: Improving maize drought tolerance by whitefly infestation.

    Science.gov (United States)

    Park, Yong-Soon; Ryu, Choong-Min

    2016-05-03

    Since plants first appeared about 1.1 billion years ago, they have been faced with biotic and abiotic stresses in their environment. To overcome these stresses, plants developed defense strategies. Accumulating evidence suggests that the whitefly [Bemisia tabaci (Genn.)] affects the regulation of plant defenses and physiology. A recent study demonstrates that aboveground whitefly infestation positively modulates root biomass and anthocyanin pigmentation on brace roots of maize plants (Zea mays L.). In agreement with these observations, indole-3-acetic acid (IAA) and jasmonic acid (JA) contents and the expression of IAA- and JA-related genes are higher in whitefly-infested maize plants than in non-infected control plants. Interestingly, the fresh weight of whitefly-infested maize plants is approximately 20% higher than in non-infected control plants under water stress conditions. Further investigation has revealed that hydrogen peroxide (H2O2) accumulates in whitefly-infested maize plants after water stoppage. Taken together, these results suggest that activation of phytohormones- (i.e., IAA and JA) and H2O2-mediated maize signaling pathways triggered by aboveground whitefly infestation promotes drought resistance. They also provide an insight into how inter-kingdom interactions can improve drought tolerance in plants.

  12. Chitosan functional properties.

    Science.gov (United States)

    Shepherd, R; Reader, S; Falshaw, A

    1997-06-01

    Chitosan is a partially deacetylated polymer of N-acetyl glucosamine. It is essentially a natural, water-soluble, derivative of cellulose with unique properties. Chitosan is usually prepared from chitin (2 acetamido-2-deoxy beta-1,4-D-glucan) and chitin has been found in a wide range of natural sources (crustaceans, fungi, insects, annelids, molluscs, coelenterata etc.) However chitosan is only manufactured from crustaceans (crab and crayfish) primarily because a large amount of the crustacean exoskeleton is available as a by product of food processing. Squid pens (a waste byproduct of New Zealand squid processing) are a novel, renewable source of chitin and chitosan. Squid pens are currently regarded as waste and so the raw material is relatively cheap. This study was intended to assess the functional properties of squid pen chitosan. Chitosan was extracted from squid pens and assessed for composition, rheology, flocculation, film formation and antimicrobial properties. Crustacean chitosans were also assessed for comparison. Squid chitosan was colourless, had a low ash content and had significantly improved thickening and suspending properties. The flocculation capacity of squid chitosan was low in comparison with the crustacean sourced chitosans. However it should be possible to increase the flocculation capacity of squid pen chitosan by decreasing the degree of acetylation. Films made with squid chitosan were more elastic than crustacean chitosan with improved functional properties. This high quality chitosan could prove particularly suitable for medical/analytical applications.

  13. Seed priming improves early seedling vigor, growth and productivity of spring maize

    Institute of Scientific and Technical Information of China (English)

    Hafeez ur Rehman[1; Hassan lqbal[1; Shahzad M A Basra[1; Irfan Afzal[1; Muhammad Farooq[2; Abdul Wakeel[3; WANG Ning[4

    2015-01-01

    Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water (hydropriming), CaCI2 (2.2%, osmopriming), moringa leaf extracts (MLE 3.3%, osmopriming) and salicylic acid (SA, 50 mg L-1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in eady planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyll contents followed by osmopriming with CaCI2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed pdming; however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.

  14. Seed priming improves early seedling vigor, growth and productivity of spring maize

    Institute of Scientific and Technical Information of China (English)

    Hafeez ur Rehman; Hassan Iqbal; Shahzad M A Basra; Irfan Afzal; Muhammad Farooq; Abdul Wakeel; WANG Ning

    2015-01-01

    Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water (hydropriming), CaCl2 (2.2%, osmopriming), moringa leaf extracts (MLE 3.3%, osmopriming) and salicylic acid (SA, 50 mg L–1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in early planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyl contents fol owed by osmopriming with CaCl2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed priming;however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.

  15. Conservation agriculture practices in rainfed uplands of India improve maize-based system productivity and profitability

    Directory of Open Access Journals (Sweden)

    Aliza Pradhan

    2016-07-01

    Full Text Available Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift towards more sustainable cropping systems such as conservation agriculture production systems (CAPS may help in maintaining soil quality as well as improving crop production and farmer’s net economic benefit. This research assessed the effects over three years (2011-2014 of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation i.e. minimum tillage, maize-cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e. conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs.

  16. Conservation Agriculture Practices in Rainfed Uplands of India Improve Maize-Based System Productivity and Profitability.

    Science.gov (United States)

    Pradhan, Aliza; Idol, Travis; Roul, Pravat K

    2016-01-01

    Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift toward more sustainable cropping systems such as conservation agriculture production systems (CAPSs) may help in maintaining soil quality as well as improving crop production and farmer's net economic benefit. This research assessed the effects over 3 years (2011-2014) of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation, i.e., minimum tillage, maize-cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e., conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs.

  17. Increased grain yield with improved photosynthetic characters in modern maize parental lines

    Institute of Scientific and Technical Information of China (English)

    LI Cong-feng; TAO Zhi-qiang; LIU Peng; ZHANG Ji-wang; ZHUANG Ke-zhang; DONG Shu-ting; ZHAO Ming

    2015-01-01

    The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech-nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass signiifcantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyl , and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Pn) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photo-chemistry efifciency (ФPSI ) and the maximum PSII photochemistry efifciency (Fv/Fm), which largely improved light partition-ing and chlorophyl lfuorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamel ae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which wil greatly help to improve photosynthetic capacity and energy efifciency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capac-ity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.

  18. Increased grain yield with improved photosynthetic characters in modern maize parental lines

    Institute of Scientific and Technical Information of China (English)

    LI Cong-feng[1; TAO Zhi-qiang[1; LIU Peng[2; ZHANG Ji-wang[2; ZHUANG Ke-zhang[3; DONG Shu-ting[2; ZHAO Ming[1

    2015-01-01

    The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech- nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass significantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyll, and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Po) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photo- chemistry efficiency (Ps,) and the maximum PSII photochemistry efficiency (FJFm), which largely improved light partition- ing and chlorophyll fluorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamellae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which will greatly help to improve photosynthetic capacity and energy efficiency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capac- ity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.

  19. 3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Machado, C B [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Ventura, J M G [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Lemos, A F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Ferreira, J M F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Leite, M F [Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Goes, A M [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil)

    2007-06-01

    A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation.

  20. Eugenol-loaded chitosan nanoparticles: I. Thermal stability improvement of eugenol through encapsulation.

    Science.gov (United States)

    Woranuch, Sarekha; Yoksan, Rangrong

    2013-07-25

    The objective of the present work was to improve the thermal stability of eugenol by encapsulating into chitosan nanoparticles via an emulsion-ionic gelation crosslinking method. The influences of the initial eugenol content and tripolyphosphate (TPP) concentration on the loading capacity (LC), encapsulation efficiency (EE), morphology and surface charge of the eugenol-loaded chitosan nanoparticles were also investigated. LC and EE tended to increase with increasing initial eugenol content and decreasing TPP concentration. Particles with LC of 12% and EE of 20% exhibited a spherical shape with an average size of less than 100 nm. Thermal stability of the encapsulated eugenol was verified through its extrusion at 155°C with a model plastic, i.e. thermoplastic flour (TPF). TPF containing encapsulated eugenol showed 8-fold higher remaining eugenol content and 2.7-fold greater radical scavenging activity than that containing naked eugenol. The results suggest the possible use of eugenol-loaded chitosan nanoparticles as antioxidants in bioactive plastics for food packaging.

  1. Prosopis alba exudate gum as excipient for improving fish oil stability in alginate-chitosan beads.

    Science.gov (United States)

    Vasile, Franco Emanuel; Romero, Ana María; Judis, María Alicia; Mazzobre, María Florencia

    2016-01-01

    The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect.

  2. Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment.

    Science.gov (United States)

    Abebe, Lydia S; Chen, Xinyu; Sobsey, Mark D

    2016-02-27

    The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI) between 4.7 (± 1.56) and 7.5 (± 0.02) log10 for Escherichia coli, and between 2.8 (± 0.10) and 4.5 (± 1.04) log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

  3. Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment

    Directory of Open Access Journals (Sweden)

    Lydia S. Abebe

    2016-02-01

    Full Text Available The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI between 4.7 (±1.56 and 7.5 (±0.02 log10 for Escherichia coli, and between 2.8 (±0.10 and 4.5 (±1.04 log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities < 1 NTU, which meet turbidity standards of the US EPA and guidance by the World Health Organization (WHO. According to WHO health-based microbial removal targets for household water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

  4. Nano-MgO reinforced chitosan nanocomposites for high performance packaging applications with improved mechanical, thermal and barrier properties.

    Science.gov (United States)

    De Silva, R T; Mantilaka, M M M G P G; Ratnayake, S P; Amaratunga, G A J; de Silva, K M Nalin

    2017-02-10

    Chitosan nanocomposite thin films were fabricated by incorporating MgO nanoparticles to significantly improve its physical properties for potential packaging applications. A novel in-situ method was developed to synthesise spherical shaped MgO nanoparticles by heat-treating magnesium carbonate/poly(methyl methacrylate) (PMMA) composite precursor. Optimum mechanical properties of chitosan composites were yielded at 5 (w/w%) of MgO concentration, where tensile stress and elastic modulus significantly improved by 86% and 38%, respectively, compared to those of pure chitosan films. These improvements are due to the interaction of hydroxyl and amine groups of chitosan with MgO as confirmed by FTIR spectroscopy. Fracture surface morphology indicated the interplay between MgO dispersion and aggregation on the mechanical properties at different MgO concentrations. Furthermore, the chitosan/MgO nanocomposites displayed remarkable thermal stability, flame retardant properties (satisfied V0 rating according to the UL-94 standards), UV shielding and moisture barrier properties, which could certainly add value to the packaging material.

  5. Chitosan-based nanoparticles for improved anticancer efficacy and bioavailability of mifepristone

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    Huijuan Zhang

    2016-11-01

    Full Text Available In addition to its well-known abortifacient effect, mifepristone (MIF has been used as an anticancer drug for various cancers in many studies with an in-depth understanding of the mechanism of action. However, application of MIF is limited by its poor water solubility and low oral bioavailability. In this work, we developed a drug delivery system based on chitosan nanoparticles (CNs to improve its bioavailability and anticancer activity. The MIF-loaded chitosan nanoparticles (MCNs were prepared by convenient ionic gelation techniques between chitosan (Cs and tripolyphosphate (TPP. The preparation conditions, including Cs concentration, TPP concentration, Cs/MIF mass ratio, and pH value of the TPP solution, were optimized to gain better encapsulation efficiency (EE and drug loading capacity (DL. MCNs prepared with the optimum conditions resulted in spherical particles with an average size of 200 nm. FTIR and XRD spectra verified that MIF was successfully encapsulated in CNs. The EE and DL of MCNs determined by HPLC were 86.6% and 43.3%, respectively. The in vitro release kinetics demonstrated that MIF was released from CNs in a sustained-release manner. Compared with free MIF, MCNs demonstrated increased anticancer activity in several cancer cell lines. Pharmacokinetic studies in male rats that were orally administered MCNs showed a 3.2-fold increase in the area under the curve from 0 to 24 h compared with free MIF. These results demonstrated that MCNs could be developed as a potential delivery system for MIF to improve its anticancer activity and bioavailability.

  6. The effects of improved maize technology on household welfare in Buruku, Benue State, Nigeria

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    Victoria I. Audu

    2014-12-01

    Full Text Available This study was carried out to determine the welfare effects of improved maize technology in Buruku Local Government Area of Benue State, Nigeria. The study also examined the determinants of the adoption of improved maize technology. Structured questionnaires were used in collecting the primary data for the study. A multi-stage random technique was used in selecting 125 farm households for the study. The Logit and ordinary least square (OLS models were used in analyzing the data. The OLS results show that adoption of improved maize varieties is positively and significantly related to household welfare and thus has contributed to moving farm households out of poverty. Other variables found to be statistically significant in explaining household welfare are education, household size, and landholding. The Logit results show that age, household size, off-farm income, and education were found to be significant in influencing farmers’ adoption decisions. Some robustness checks were performed with different specifications of the Logit and OLS models as well as re-estimation with propensity matching score approach. Overall, the results are robust to different specifications.

  7. Improvement in physical and biological properties of chitosan/soy protein films by surface grafted heparin.

    Science.gov (United States)

    Wang, Xiaomei; Hu, Ling; Li, Chen; Gan, Li; He, Meng; He, Xiaohua; Tian, Weiqun; Li, Mingming; Xu, Li; Li, Yinping; Chen, Yun

    2016-02-01

    A series of chitosan/soy protein isolate (SPI) composite films (CS-n, n=0, 10 and 30, corresponding to SPI content in the composites) were prepared. Heparin was grafted onto the surface of CS-n to fabricate a series of heparinized films (HCS-n). CS-n and HCS-n were characterized by ATR-Fourier transform infrared spectroscopy and water contact angle. The surface heparin density was measured by toluidine blue assay. The results showed that heparin has been successfully grafted onto the surface of CS-n. Heparin evenly distributed on the surface of the films and the heparin content increased with the increase of SPI content, and the hydrophilicity of the films was enhanced due to the grafted heparin. The cytocompatibility and hemocompatibility of CS-n and HCS-n were evaluated by cell culture (MTT assay, live/dead assay, cell morphology and cell density observation), platelet adhesion test, plasma recalcification time (PRT) measurement, hemolysis assay and thrombus formation test. HCS-n showed higher cell adhesion rate and improved cytocompatibility compared to the corresponding CS-n. HCS-n also exhibited lower platelet adhesion, longer PRT, higher blood anticoagulant indexes (BCI) and lower hemolysis rate than the corresponding CS-n. The improved cytocompatibility and hemocompatibility of HCS-n would shed light on the potential applications of chitosan/soy protein-based biomaterials that may come into contact with blood.

  8. Improved postharvest quality in patagonian squash (Cucurbita moschata) coated with radiation depolymerized chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, Maria Alicia; Goitia, Maria Teresa [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Yossen, Mariana [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC), CONICET-Universidad Nacional del Litoral, Ruta Nacional 168-Paraje ' El Pozo' , 3000 Santa Fe (Argentina); Cifone, Norma; Agullo, Enrique [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Andreucetti, Noemi, E-mail: andreuce@criba.edu.ar [Laboratorio de Radioisotopos, Departamento de Quimica, Universidad Nacional del Sur, Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina)

    2011-12-15

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes (Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan. - Highlights: > Original Chitosan was radiation depolymerized producing chitosans with lower molecular weights. > Gamma-irradiated chitosans only exhibit chain scission. > SEC-MALLS-RI chromatography is a useful tool in molecular weight analysis. > Depolymerized chitosans were the best in maintaining the quality and the storage life of coated squashes.

  9. Amendment of Tephrosia Improved Fallows with Inorganic Fertilizers Improves Soil Chemical Properties, N Uptake, and Maize Yield in Malawi

    Directory of Open Access Journals (Sweden)

    Maggie G. Munthali

    2014-01-01

    Full Text Available Maize production in Malawi is limited mainly by low soil N and P. Improved fallows of N-fixing legumes such as Tephrosia and Sesbania offer options for improving soil fertility particularly N supply. The interactions of Tephrosia fallows and inorganic fertilizers on soil properties, N uptake, and maize yields were evaluated at Chitedze Research Station in Malawi. The results indicated that the level of organic matter and pH increased in all the treatments except for the control. Total N remained almost unchanged while available P decreased in all plots amended with T. vogelii but increased in T. candida plots where inorganic P was applied. Exchangeable K increased in all the plots irrespective of the type of amendment. The interaction of N and P fertilizers with T. vogelii fallows significantly increased the grain yield. The treatment that received 45 kg N ha−1 and 20 kg P ha−1 produced significantly higher grain yields (6.8 t ha−1 than all the other treatments except where 68 kg N ha−1 and 30 kg P ha−1 were applied which gave 6.5 t ha−1 of maize grain. T. candida fallows alone or in combination with N and P fertilizers did not significantly affect grain yield. However, T. candida fallows alone can raise maize grain yield by 300% over the no-input control. Based on these results we conclude that high quality residues such as T. candida and T. vogelii can be used as sources of nutrients to improve crop yields and soil fertility in N-limited soils. However, inorganic P fertilizer is needed due to the low soil available P levels.

  10. Improved epidermal barrier formation in human skin models by chitosan modulated dermal matrices

    Science.gov (United States)

    Mieremet, Arnout; Rietveld, Marion; Absalah, Samira; van Smeden, Jeroen

    2017-01-01

    Full thickness human skin models (FTMs) contain an epidermal and a dermal equivalent. The latter is composed of a collagen dermal matrix which harbours fibroblasts. Current epidermal barrier properties of FTMs do not fully resemble that of native human skin (NHS), which makes these human skin models less suitable for barrier related studies. To further enhance the resemblance of NHS for epidermal morphogenesis and barrier formation, we modulated the collagen dermal matrix with the biocompatible polymer chitosan. Herein, we report that these collagen-chitosan FTMs (CC-FTMs) possess a well-organized epidermis and maintain both the early and late differentiation programs as in FTMs. Distinctively, the epidermal cell activation is reduced in CC-FTMs to levels observed in NHS. Dermal-epidermal interactions are functional in both FTM types, based on the formation of the basement membrane. Evaluation of the barrier structure by the organization of the extracellular lipid matrix of the stratum corneum revealed an elongated repeat distance of the long periodicity phase. The ceramide composition exhibited a higher resemblance of the NHS, based on the carbon chain-length distribution and subclass profile. The inside-out barrier functionality indicated by the transepidermal water loss is significantly improved in the CC-FTMs. The expression of epidermal barrier lipid processing enzymes is marginally affected, although more restricted to a single granular layer. The novel CC-FTM resembles the NHS more closely, which makes them a promising tool for epidermal barrier related studies. PMID:28333992

  11. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila.

    Science.gov (United States)

    Li, T; Liu, M J; Zhang, X T; Zhang, H B; Sha, T; Zhao, Z W

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments.

  12. Seed priming with chitosan improves the germination and growth performance of ajowan

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    Batool Mahdavi

    2013-11-01

    Full Text Available Background: Chitosan is a polysaccharide biopolymer derived from chitin. It not only stimulates growth and increases the crop yields but also alleviates the harmful effect of abiotic stress on plant growth. The objective of this study was to investigate the effects of chitosan on germination and growth of ajowan (Carum copticum under salt stress. This study was conducted in a laboratory and greenhouse. Material and Methods: In the first experiment seed germination of ajowan monitored under seed pre-treated by soaking in chitosan solutions of 0, 0.01%, 0.05%, 0.1%, 0.2% and 0.5% for 3 h. In second experiment, seeds soaked in chitosan solutions (0 and 0.2% and sown in pots at different salinity levels (0, 4, 8 and 12 dS/m. Results: Results indicated that all of chitosan concentrations increased germination percentage, germination rate, seedling vigour index, length and dry weight of hypocotyl and radicle compared to control although, 0.2% chitosan concentration was more effective than other treatments. Salinity caused a significant reduction in germination percentage, shoot length, root length, shoot and root dry weight and relative water content, while chitosan adjusted the salt toxicity. Conclusions: It is concluded that chitosan would be able to stimulate germination and growth of ajowan. It is also resulted that soaking ajowan seeds with chitosan, may alleviate the inhibitory effect of salt stress on the plant growth.

  13. Improved Evidence-Based Genome-scale Metabolic Models for Maize Leaf, Embryo, and Endosperm.

    Directory of Open Access Journals (Sweden)

    Samuel eSeaver

    2015-03-01

    Full Text Available There is a growing demand for genome-scale metabolic reconstructions for plants, fueled by the need to understand the metabolic basis of crop yield and by progress in genome and transcriptome sequencing. Methods are also required to enable the interpretation of plant transcriptome data to study how cellular metabolic activity varies under different growth conditions or even within different organs, tissues, and developmental stages. Such methods depend extensively on the accuracy with which genes have been mapped to the biochemical reactions in the plant metabolic pathways. Errors in these mappings lead to metabolic reconstructions with an inflated number of reactions and possible generation of unreliable metabolic phenotype predictions. Here we introduce a new evidence-based genome-scale metabolic reconstruction of maize, with significant improvements in the quality of the gene-reaction associations included within our model. We also present a new approach for applying our model to predict active metabolic genes based on transcriptome data. This method includes a minimal set of reactions associated with low expression genes to enable activity of a maximum number of reactions associated with high expression genes. We apply this method to construct an organ-specific model for the maize leaf, and tissue specific models for maize embryo and endosperm cells. We validate our models using fluxomics data for the endosperm and embryo, demonstrating an improved capacity of our models to fit the available fluxomics data. All models are publicly available via the DOE Systems Biology Knowledgebase and PlantSEED, and our new method is generally applicable for analysis transcript profiles from any plant, paving the way for further in silico studies with a wide variety of plant genomes.

  14. Preparation of chitosan nanofiber tube by electrospinning.

    Science.gov (United States)

    Matsuda, Atsushi; Kagata, Go; Kino, Rikako; Tanaka, Junzo

    2007-03-01

    Water-insoluble chitosan nanofiber sheets and tubes coated with chitosan-cast film were prepared by electrospinning. When as-spun chitosan nanofiber sheets and tubes were immersed in 28% ammonium aqueous solution, they became insoluble in water and showed nanofiber structures confirmed by SEM micrography. Mechanical properties of chitosan nanofiber sheets and tubes were improved by coating with chitosan-cast film, which gave them a compressive strength higher than that of crab-tendon chitosan, demonstrating that chitosan nanofiber tubes coated with chitosan-cast film are usable as nerve-regenerative guide tubes.

  15. Solid lipid nanoparticles for oral drug delivery: chitosan coating improves stability, controlled delivery, mucoadhesion and cellular uptake.

    Science.gov (United States)

    Luo, Yangchao; Teng, Zi; Li, Ying; Wang, Qin

    2015-05-20

    The poor stability of solid lipid nanoparticles (SLN) under acidic condition resulted in large aggregation in gastric environment, limiting their application as oral delivery systems. In this study, a series of SLN was prepared to investigate the effects of surfactant/cosurfactant and chitosan coating on their physicochemical properties as well as cellular uptake. SLN was prepared from Compritol 888 ATO using a low-energy method combining the solvent-diffusion and hot homogenization technique. Poloxamer 188 and polyethylene glycol (PEG) were effective emulsifiers to produce SLN with better physicochemical properties than SLN control. Chitosan-coated SLN exhibited the best stability under acidic condition by forming a thick layer around the lipid core, as clearly observed by transmission electron microscope. The intermolecular interactions in different formulations were monitored by Fourier transform infrared spectroscopy. Chitosan coating also significantly improved the mucoadhesive property of SLN as determined by Quartz Crystal Microbalance. In vitro drug delivery assays, cytotoxicity, and cellular uptake of SLN were studied by incorporating coumarin 6 as a fluorescence probe. Overall, chitosan-coated SLN was superior to other formulations and held promising features for its application as a potential oral drug delivery system for hydrophobic drugs.

  16. Improvements of physical, mechanical and biodegradation properties of polybutadiene rubber insulators by chitosan and silica nanoparticles.

    Science.gov (United States)

    Saboktakin, Amin; Saboktakin, Mohammadreza

    2016-10-01

    1,4-cis-Polybutadiene rubber(1,4-cis pBR) as an insulation material is developing that will provide superior thermal insulation properties, flexibility, toughness by natural polymers such as chitosan(CS) and silica nanoparticles. This material is widely used in the insulation industries specially architecture. This research concerns physical, mechanical properties and also biodegradation of 1,4-cis pBR, which to be composed with the natural polymers such as CS. Silica nanoparticles were used as filler to improve the physical and mechanical properties of 1,4-cis pBR. To evaluating its physical and mechanical properties, stretching and bending and impact tests were used and the results show some improvement in these properties. Our observations show that temperature plays an important role as main factor in order to improve the mechanical properties of nanocomposites. Similar improvements in tensile modulus and strength have been observed for 1,4-cis pBR/CS-silica nanoparticles.

  17. Improved postharvest quality in patagonian squash ( Cucurbita moschata) coated with radiation depolymerized chitosan

    Science.gov (United States)

    Pugliese, Maria Alicia; Goitia, Maria Teresa; Yossen, Mariana; Cifone, Norma; Agulló, Enrique; Andreucetti, Noemi

    2011-12-01

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes ( Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan.

  18. Stabilization of porous chitosan improves the performance of its association with platelet-rich plasma as a composite scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Shimojo, A.A.M., E-mail: lshimojo51@gmail.com; Perez, A.G.M.; Galdames, S.E.M.; Brissac, I.C.S.; Santana, M.H.A.

    2016-03-01

    This study offers innovative perspectives for optimizing of scaffolds based on correlation structure–function aimed the regenerative medicine. Thus, we evaluated in vitro performance of stabilized porous chitosan (SPCHTs) associated with activated platelet-rich plasma (aP-PRP) as a composite scaffold for the proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells (h-AdMSCs). The porous structure of chitosan (PCHT) was prepared similarly to solid sponges by controlled freezing (− 20 °C) and lyophilization of a 3% (w/v) chitosan solution. Stabilization was performed by treating the PCHT with sodium hydroxide (TNaOH), an ethanol series (TEtOH) or by crosslinking with tripolyphosphate (CTPP). The aP-PRP was obtained from the controlled centrifugation of whole blood and activated with autologous serum and calcium. Imaging of the structures showed fibrin networks inside and on the surface of SPCHTs as a consequence of electrostatic interactions. SPCHTs were non-cytotoxic, and the porosity, pore size and Young's modulus were approximately 96%, 145 μm and 1.5 MPa for TNaOH and TEtOH and 94%, 110 μm and 1.8 MPa for CTPP, respectively. Stabilization maintained the integrity of the SPCHTs for at least 10 days of cultivation. SPCHTs showed controlled release of the growth factors TGF-β1 and PDGF-AB. Although generating different patterns, all of the stabilization treatments improved the proliferation of seeded h-AdMSCs on the composite scaffold compared to aP-PRP alone, and differentiation of the composite scaffold treated with TEtOH was significantly higher than for non-stabilized PCHT. We conclude that the composite scaffolds improved the in vitro performance of PRP and have potential in regenerative medicine. - Highlights: • Stabilization maintains the integrity of the chitosan scaffolds for at least 10 days. • Fibrin networks on the chitosan scaffolds were referred to electrostatic interactions. • Stabilized chitosan

  19. Improvement of antioxidant and antimicrobial activity of chitosan film with caraway and oregano essential oils

    Directory of Open Access Journals (Sweden)

    Hromiš Nevena M.

    2014-01-01

    Full Text Available In this work, caraway or oregano essential oils were added to the cast chitosan film in an attempt to design a natural, biodegradable, bioactive (antioxidant and antimicrobial packaging film. When the structure of the tested films was analyzed with Fourier transform infrared spectroscopy, no significant differences were found between the chitosan film with and without essential oils of caraway or oregano. The lowest antioxidant activity, based on the scavenging of the stable DPPH• free radical, was detected for the chitosan film without oil addition, going from 11.64%, after 2.5 h to 28.96%, after 24 h. When the caraway essential oil was added to the chitosan film, the antioxidant activity was increased (p<0.05 to 33.47±4.77%, after 2.5 h and to 81.08±0.64%, after 24 h. This increase in the antioxidant activity was even higher in the film with oregano essential oil (p<0.05. After 2.5 h, the value for the antioxidant activity of the chitosan-oregano film was 87.58±1.71%, and after 4 h and 24 h it was above 90%. The obtained results for the antimicrobial activity showed that the chitosan film is an effective antimicrobial agent against Escherichia coli and Staphylococcus aureus. When caraway essential oil was added in 1% volume concentration to the film, no increase in the antimicrobial action of chitosan film was detected. On the other hand, the addition of oregano essential oil promoted chitosan film antimicrobial activity, which was particularly evident with Escherichia coli. The results showed that the chitosan film can be successfully applied as a matrix carrier for essential oils in the active film system.[ Projekat Ministarstva nauke Republike Srbije, br. TR31032

  20. Physiological Strategies to Improve the Performance of Spring Maize (Zea mays L. Planted under Early and Optimum Sowing Conditions.

    Directory of Open Access Journals (Sweden)

    Muhammad Amir Bakhtavar

    Full Text Available Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE and 100 mg L-1 kinetin solution alone or in all possible combinations with each other at three growth stages (knee height, tasseling and grain filling stage and hydropriming was compared with control. Seed priming plus foliar spray of MLE and kinetin significantly improved stand establishment especially under early sown crop as indicated by reduced mean emergence time (MET, improved emergence index (EI and final emergence percentage (FEP. Similarly increased chlorophyll contents, crop growth rate, leaf area index, photosynthetic rate, transpiration rate, relative water content and decreased membrane permeability were recorded in both early and optimum sowing conditions in MLE priming plus foliar spray treatment. All these improvements were harvested in the form of increased yield and harvest index compared with control treatment. Overall crop sown at optimum time performed best but exogenous application of MLE through seed priming and foliar spray maximally improved the performance of early sown maize crop which is attributed more likely due to improved stand establishment, chlorophyll and phenolic contents, increased leaf area duration and grain filling period. It can be concluded that seed priming with MLE along with its foliar spray could increase production of maize under temperature extremes.

  1. Physiological Strategies to Improve the Performance of Spring Maize (Zea mays L.) Planted under Early and Optimum Sowing Conditions.

    Science.gov (United States)

    Bakhtavar, Muhammad Amir; Afzal, Irfan; Basra, Shahzad Maqsood Ahmed; Ahmad, Azraf-Ul-Haq; Noor, Mehmood Ali

    2015-01-01

    Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE) and 100 mg L-1 kinetin solution alone or in all possible combinations with each other at three growth stages (knee height, tasseling and grain filling stage) and hydropriming was compared with control. Seed priming plus foliar spray of MLE and kinetin significantly improved stand establishment especially under early sown crop as indicated by reduced mean emergence time (MET), improved emergence index (EI) and final emergence percentage (FEP). Similarly increased chlorophyll contents, crop growth rate, leaf area index, photosynthetic rate, transpiration rate, relative water content and decreased membrane permeability were recorded in both early and optimum sowing conditions in MLE priming plus foliar spray treatment. All these improvements were harvested in the form of increased yield and harvest index compared with control treatment. Overall crop sown at optimum time performed best but exogenous application of MLE through seed priming and foliar spray maximally improved the performance of early sown maize crop which is attributed more likely due to improved stand establishment, chlorophyll and phenolic contents, increased leaf area duration and grain filling period. It can be concluded that seed priming with MLE along with its foliar spray could increase production of maize under temperature extremes.

  2. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    OpenAIRE

    Mayumi Egusa; Ryo Iwamoto; Hironori Izawa; Minoru Morimoto; Hiroyuki Saimoto; Hironori Kaminaka; Shinsuke Ifuku

    2015-01-01

    Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth in...

  3. Kinetics of phosphorus uptake and root morphology of local and improved varieties of maize

    Directory of Open Access Journals (Sweden)

    Machado Cynthia Torres de Toledo

    2004-01-01

    Full Text Available Interspecific and intraspecific differences in the efficiency of utilization of soil phosphorus (P are explained, in part, by plant morphological and physiological variations, which characterize the plant for nutrient acquisition. As part of a study on maize genotypes characterization for P-uptake and use efficiency, kinetic parameters of P uptake and root morphological characters were evaluated for six local and improved maize varieties, grown in nutrient solution. The kinetic parameters related to P influx were: maximal transport rate (Vmax, the Michaelis-Menten constant (Km, and the external concentration when net uptake is zero (Cmin. Measured root morphological characters were: root length, radius, and surface area. Shoot and root dry matter yield and the P content in these parts were also determined. Diferences among varieties were observed in the kinetic parameters Vmax and Km, root length and in root/shoot dry matter ratio. Lower Km values were better indicatives of P uptake ability of the varietes and were significantly correlated to higher dry matter production and P-efficiency index.

  4. Survey of Genomics Approaches to Improve Bioenergy Traits in Maize, Sorghum and Sugarcane

    Institute of Scientific and Technical Information of China (English)

    Wilfred Vermerris

    2011-01-01

    Bioenergy crops currently provide the only source of alternative energy with the potential to reduce the use of fossil transportation fuels in a way that is compatible with existing engine technology, including in developing countries. Even though bioenergy research is currently receiving considerable attention, many of the concepts are not new,but rather build on intense research efforts from 30 years ago. A major difference with that era is the availability of genomics tools that have the potential to accelerate crop improvement significantly. This review is focused on maize, sorghum and sugarcane as representatives of bioenergy grasses that produce sugar and/or lignocellulosic biomass.Examples of how genetic mapping, forward and reverse genetics, high-throughput expression profiling and comparative genomics can be used to unravel and improve bioenergy traits will be presented.

  5. Genetic Improvement of Root Growth Contributes to Efficient Phosphorus Acquisition in maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-kai; CHEN Fan-jun; CHEN Xiao-chao; LONG Li-zhi; GAO Kun; YUAN Li-xing; ZHANG Fu-suo; MI Guo-hua

    2013-01-01

    Maize plants adapt to low phosphorus (P) stress by increasing root growth. It is of importance to know the extent to which genetic improvement of root growth can enhance P acquisiton. In the present study, the contribution of root growth improvement to efficient P acquisition was evaluated in two soils using T149 and T222, a pair of near isogenic maize testcrosses which were derived from a backcross BC4F3 population. T149 and T222 showed no difference in shoot biomass and leaf area under normal growth conditions, but differed greatly in root growth. T149 had longer lateral roots and a larger root surface area compared to T222. In calcareous soil, when P was insufficient, i.e., when P was either supplied as KH2PO4 at a concentration of 50 mg P kg-1 soil, or in the form of Phy-P, Ca3-P or Ca10-P, a 43%increase in root length in T149 compared to T222 resulted in an increase in P uptake by 53%, and shoot biomass by 48%. In acid soil, however, when P supply was insufficient, i.e., when P was supplied as KH2PO4 at a concentration of 100 mg P kg-1 soil, or in the form of Phy-P, Fe-P or Al-P, a 32%increase in root length in T149 compared to T222 resulted in an increase in P uptake by only 12%, and shoot biomass by 7%. No significant differences in the exudation of organic acids and APase activity were found between the two genotypes. It is concluded that genetic improvement of root growth can efficiently increase P acquisition in calcareous soils. In acid soils, however, improvements in the physiological traits of roots, in addition to their size, seem to be required for efficient P acquisition.

  6. Improved barrier and mechanical properties of novel hydroxypropyl methylcellulose edible films with chitosan/tripolyphosphate nanoparticles

    Science.gov (United States)

    Chitosan/tripolyphosphate nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films. FT-IR and transmission electron microscopy (TEM) analyses of the nanoparticles, mechanical properties, water vapor permeability, thermal stability, scanning electron microscopy (SEM...

  7. The alginate layer for improving doxorubicin release and radiolabeling stability of chitosan hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jeong Il; Lee, Chang Moon; Jeong, Hwan Seok; Hwang, Hyo Sook; Lim, Seok Tae; Sohn, Myung Hee; Jeong, Hwan Jeong [Dept. of Nuclear Medicine and Therapeutic Medicine Research Center, Cyclotron Research Center, Institute for Medical Science, Biomedical Research Institute, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Chang Moon [Dept. of Biomedical Engineering, Chonnam National University, Yeosu (Korea, Republic of)

    2015-12-15

    Chitosan hydrogels (CSH) formed through ionic interaction with an anionic molecule are suitable as a drug carrier and a tissue engineering scaffold. However, the initial burst release of drugs from the CSH due to rapid swelling after immersing in a biofluid limits their wide application as a drug delivery carrier. In this study, alginate layering on the surface of the doxorubicin (Dox)-loaded and I-131-labeled CSH (DI-CSH) was performed. The effect of the alginate layering on drug release behavior and radiolabeling stability was investigated. Chitosan was chemically modified using a chelator for I-131 labeling. After labeling of I-131 and mixing of Dox, the chitosan solution was dropped into tripolyphosphate (TPP) solution using an electrospinning system to prepare spherical microhydrogels. The DI-CSH were immersed into alginate solution for 30 min to form the crosslinking layer on their surface. The formation of alginate layer on the DI-CSH was confirmed by Fourier transform infrared spectroscopy (FT-IR) and zeta potential analysis. In order to investigate the effect of alginate layer, studies of in vitro Dox release from the hydrogels were performed in phosphate buffered in saline (PBS, pH 7.4) at 37 °C for 12 days. The radiolabeling stability of the hydrogels was evaluated using ITLC under different experimental condition (human serum, normal saline, and PBS) at 37 °C for 12 days. Formatting the alginate-crosslinked layer on the CSH surface did not change the spherical morphology and the mean diameter (150 ± 10 μm). FT-IR spectra and zeta potential values indicate that alginate layer was formed successfully on the surface of the DI-CSH. In in vitro Dox release studies, the total percentage of the released Dox from the DI-CSH for 12 days were 60.9 ± 0.8, 67.3 ± 1.4, and 71.8 ± 2.5 % for 0.25, 0.50, and 1.00 mg Dox used to load into the hydrogels, respectively. On the other hand, after formatting alginate layer, the percentage of the

  8. Breeding of speciality maize for industrial purposes

    OpenAIRE

    2010-01-01

    The breeding programme on speciality maize with specific traits was established at the Maize Research Institute, Zemun Polje, several decades ago. The initial material was collected, new methods applying to breeding of speciality maize, i.e. popping maize, sweet maize and white-seeded maize, were introduced. The aim was to enhance and improve variability of the initial material for breeding these three types of maize. Then, inbred lines of good combining abilities were developed and used as c...

  9. "Bio-glues" to Enhance Slipperiness of Mucins: Improved Lubricity and Wear Resistance of Porcine Gastric Mucin (PGM) Layers Assisted by Mucoadhesion with Chitosan

    DEFF Research Database (Denmark)

    Nikogeorgos, Nikolaos; Efler, Petr; Lee, Seunghwan

    2015-01-01

    A synergetic lubricating effect between porcine gastric mucin (PGM) and chitosan based on their mucoadhesive interaction is reported at a hydrophobic interface comprised of self-mated polydimethylsiloxane (PDMS) surfaces. In acidic solution (pH 3.2) and low concentrations (0.1 mg mL- 1), the inte......A synergetic lubricating effect between porcine gastric mucin (PGM) and chitosan based on their mucoadhesive interaction is reported at a hydrophobic interface comprised of self-mated polydimethylsiloxane (PDMS) surfaces. In acidic solution (pH 3.2) and low concentrations (0.1 mg mL- 1......), the interaction of PGM with chitosan led to surface recharge and size shrinkage of their aggregates. This resulted in higher mass adsorption on the PDMS surface with increasing weight ratio of [chitosan]/[PGM + chitosan] up to 0.50. While neither PGM nor chitosan exhibited slippery characteristics, coefficient...... of friction being close to 1, their mixture improved considerably the lubricating efficiency (coefficient of friction 0.011 at optimum mixing ratio) and wear resistance of the adsorbed layers. These findings are explained by the role of chitosan as a physical crosslinker within the adsorbed PGM layers...

  10. Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers

    Science.gov (United States)

    Hidalgo, T.; Giménez-Marqués, M.; Bellido, E.; Avila, J.; Asensio, M. C.; Salles, F.; Lozano, M. V.; Guillevic, M.; Simón-Vázquez, R.; González-Fernández, A.; Serre, C.; Alonso, M. J.; Horcajada, P.

    2017-01-01

    Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction between the CS and the nanoparticles has been characterized through a combination of high resolution soft X-ray absorption and computing simulation, while the positive impact of the coating on the colloidal and chemical stability under oral simulated conditions is here demonstrated. Finally, the intestinal barrier bypass capability and biocompatibility of CS-coated nanoMOF have been assessed in vitro, leading to an increased intestinal permeability with respect to the non-coated material, maintaining an optimal biocompatibility. In conclusion, the preservation of the interesting physicochemical features of the CS-coated nanoMOF and their adapted colloidal stability and progressive biodegradation, together with their improved intestinal barrier bypass, make these nanoparticles a promising oral nanocarrier. PMID:28256600

  11. Functional poly(ε-caprolactone)/chitosan dressings with nitric oxide-releasing property improve wound healing.

    Science.gov (United States)

    Zhou, Xin; Wang, He; Zhang, Jimin; Li, Xuemei; Wu, Yifan; Wei, Yongzhen; Ji, Shenglu; Kong, Deling; Zhao, Qiang

    2017-03-09

    Wound healing dressings are increasingly needed clinically due to the large number of skin damage annually. Nitric oxide (NO) plays a key role in promoting wound healing, thus biomaterials with NO-releasing property receive increasing attention as ideal wound dressing. In present study, we prepared a novel functional wound dressing by combining electrospun poly(ε-caprolactone) (PCL) nonwoven mat with chitosan-based NO-releasing biomaterials (CS-NO). As-prepared PCL/CS-NO dressing released NO sustainably under the physiological conditions, which was controlled by the catalysis of β-galactosidase. In vivo wound healing characteristics were further evaluated on full-thickness cutaneous wounds in mice. Results showed that PCL/CS-NO wound dressings remarkably accelerated wound healing process through enhancing re-epithelialization and granulation formation and effectively improved the organization of regenerated tissues including epidermal-dermal junction, which could be ascribed to the pro-angiogenesis, immunomodulation, and enhanced collagen synthesis provided by the sustained release of NO. Therefore, PCL/CS-NO may be a promising candidate for wound dressings, especially for the chronic wound caused by the ischemia.

  12. Novel albendazole-chitosan nanoparticles for intestinal absorption enhancement and hepatic targeting improvement in rats.

    Science.gov (United States)

    Liu, Yang; Wang, Xiao-qing; Ren, Wei-xin; Chen, Yuan-lan; Yu, Yang; Zhang, Jian-kang; Bawudong, Dilimulati; Gu, Jun-peng; Xu, Xiao-dong; Zhang, Xue-nong

    2013-08-01

    To improve the treatment of helminthiasis, filariasis, and colorectal cancer, albendazole-associated chitosan nanoparticles (ABZ-CS-NPs) were prepared using the emulsion crosslinking volatile technique with contained sodium tripolyphosphate as the crosslinking agent and Poloxamer 188 as the auxiliary solvent. The structural characteristics of the NPs were determined using X-ray diffraction to analyze the interaction between CS and the drug. The NPs were then evaluated in terms of their physicochemical characteristics, drug release behavior, in vivo pharmacokinetic parameters, and biodistribution in animal studies. ABZ-loaded NPs with a uniformly spherical particle sizes (157.8 ± 2.82 nm) showed efficient drug loading, encapsulated efficiency, and high physical stability. The drug release from ABZ-CS-NPs was extended over several periods. Kinetic models were then fitted to determine the release mechanisms. ABZ and its metabolite albendazole sulfoxide (ABZSX) were analyzed in rats with mebendazole as the internal standard using reversed-phase high-performance liquid chromatography. Compared with the ABZ suspension groups, the relative bioavailability values of ABZ and ABZSX were 146.05 and 222.15%, respectively. In addition, the plasma concentration versus time curve is consistent with that of the two compartment models in the plasma concentration versus time curve. The results indicate that the ABZ-loaded NPs are promising novel ABZ candidates for passive diffusion in the treatment of hydatid cysts in the liver via oral administration.

  13. Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers

    Science.gov (United States)

    Hidalgo, T.; Giménez-Marqués, M.; Bellido, E.; Avila, J.; Asensio, M. C.; Salles, F.; Lozano, M. V.; Guillevic, M.; Simón-Vázquez, R.; González-Fernández, A.; Serre, C.; Alonso, M. J.; Horcajada, P.

    2017-03-01

    Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction between the CS and the nanoparticles has been characterized through a combination of high resolution soft X-ray absorption and computing simulation, while the positive impact of the coating on the colloidal and chemical stability under oral simulated conditions is here demonstrated. Finally, the intestinal barrier bypass capability and biocompatibility of CS-coated nanoMOF have been assessed in vitro, leading to an increased intestinal permeability with respect to the non-coated material, maintaining an optimal biocompatibility. In conclusion, the preservation of the interesting physicochemical features of the CS-coated nanoMOF and their adapted colloidal stability and progressive biodegradation, together with their improved intestinal barrier bypass, make these nanoparticles a promising oral nanocarrier.

  14. Cellulose acetate/hydroxyapatite/chitosan coatings for improved corrosion resistance and bioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhenyu; Qin, Jinli [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ma, Jun, E-mail: caltary@gmail.com [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Biomedical Engineering, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-04-01

    Cellulose acetate (CA) nanofibers were deposited on stainless steel plates by electrospinning technique. The composite of hydroxyapatite (HAP) nanoparticles and chitosan (CHI) was coated subsequently by dip-coating. The structure and morphology of the obtained coatings were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The stability of the coatings in physiological environment was studied using electrochemical polarization and impedance spectroscopy. The CA nanofibers were embedded in the HAP/CHI coating and the resulted composite film was densely packed and uniform on the substrate. The in vitro biomineralization study of the coated samples immersed in simulated body fluid (SBF) confirmed the formation ability of bone-like apatite layer on the surface of HAP-containing coatings. Furthermore, the coatings could provide corrosion resistance to the stainless steel substrate in SBF. The electrochemical results suggested that the incorporation of CA nanofibers could improve the corrosion resistance of the HAP/CHI coating. Thus, biocompatible CA/HAP/CHI coated metallic implants could be very useful in the long-term stability of the biomedical applications. - Highlights: • The composite coatings were prepared by electrospinning and dip-coating. • Good in vitro bioactivity of the CA/HAP/CHI coating was confirmed. • Electrochemical behaviors in SBF of the coatings have been studied. • The CA/HAP/CHI coating shows better resistance property than HAP/CHI.

  15. Broadening Our Portfolio in the Genetic Improvement of Maize Chemical Composition.

    Science.gov (United States)

    Wen, Weiwei; Brotman, Yariv; Willmitzer, Lothar; Yan, Jianbing; Fernie, Alisdair R

    2016-08-01

    The adoption of recombinant inbred line and introgression line populations, as well as the study of association mapping panels, has greatly accelerated our ability to identify the genes underlying plant phenotypic variance. In tandem, the development of metabolomics approaches has greatly enhanced our ability to comprehensively define cellular chemical composition. As a consequence, breeding for chemical composition is being extended beyond our traditional targets of oil and protein to include components such as essential amino acids, vitamins, and antioxidant secondary metabolites with considerable purported consequences for human health. Here, we review the above-mentioned developments paying particular attention to the genetic architecture of metabolic traits as well as updating the perspective for utilizing metabolomics in maize improvement.

  16. Potassium Management for Improving Growth and Grain Yield of Maize (Zea mays L.) under Moisture Stress Condition

    Science.gov (United States)

    Amanullah; Iqbal, Asif; Irfanullah; Hidayat, Zeeshan

    2016-01-01

    Potassium (K) fertilizer management is beneficial for improving growth, yield and yield components of field crops under moisture stress condition in semiarid climates. Field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to foliar and soil applied K during summer 2013 and 2014. The experiments were carried out at the Agronomy Research Farm of The University of Agriculture Peshawar, Northwest Pakistan under limited irrigation (moisture stress) condition. It was concluded from the results that application of foliar K at the rate of 1–3% and foliar Zn at the rate of 0.1–0.2% was more beneficial in terms of better growth, higher yield and yield components of maize under moisture stress condition. Early spray (vegetative stage) resulted in better growth and higher yield than late spray (reproductive stage). Soil K treated plots (rest) plots performed better than control (K not applied) in terms of improved growth, higher yield and yield components of maize crop. The results further demonstrated that increasing the rate of soil applied K up to 90 kg P ha−1 in two equal splits (50% each at sowing and knee height) improve growth and maize productivity under semiarid climates. PMID:27694964

  17. Potassium Management for Improving Growth and Grain Yield of Maize (Zea mays L.) under Moisture Stress Condition.

    Science.gov (United States)

    Amanullah; Iqbal, Asif; Irfanullah; Hidayat, Zeeshan

    2016-10-03

    Potassium (K) fertilizer management is beneficial for improving growth, yield and yield components of field crops under moisture stress condition in semiarid climates. Field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to foliar and soil applied K during summer 2013 and 2014. The experiments were carried out at the Agronomy Research Farm of The University of Agriculture Peshawar, Northwest Pakistan under limited irrigation (moisture stress) condition. It was concluded from the results that application of foliar K at the rate of 1-3% and foliar Zn at the rate of 0.1-0.2% was more beneficial in terms of better growth, higher yield and yield components of maize under moisture stress condition. Early spray (vegetative stage) resulted in better growth and higher yield than late spray (reproductive stage). Soil K treated plots (rest) plots performed better than control (K not applied) in terms of improved growth, higher yield and yield components of maize crop. The results further demonstrated that increasing the rate of soil applied K up to 90 kg P ha(-1) in two equal splits (50% each at sowing and knee height) improve growth and maize productivity under semiarid climates.

  18. Alfalfa (Medicago sativa L./maize (Zea mays L. intercropping provides a feasible way to improve yield and economic incomes in farming and pastoral areas of northeast China.

    Directory of Open Access Journals (Sweden)

    Baoru Sun

    Full Text Available Given the growing challenges to food and eco-environmental security as well as sustainable development of animal husbandry in the farming and pastoral areas of northeast China, it is crucial to identify advantageous intercropping modes and some constraints limiting its popularization. In order to assess the performance of various intercropping modes of maize and alfalfa, a field experiment was conducted in a completely randomized block design with five treatments: maize monoculture in even rows, maize monoculture in alternating wide and narrow rows, alfalfa monoculture, maize intercropped with one row of alfalfa in wide rows and maize intercropped with two rows of alfalfa in wide rows. Results demonstrate that maize monoculture in alternating wide and narrow rows performed best for light transmission, grain yield and output value, compared to in even rows. When intercropped, maize intercropped with one row of alfalfa in wide rows was identified as the optimal strategy and the largely complementary ecological niches of alfalfa and maize were shown to account for the intercropping advantages, optimizing resource utilization and improving yield and economic incomes. These findings suggest that alfalfa/maize intercropping has obvious advantages over monoculture and is applicable to the farming and pastoral areas of northeast China.

  19. Alfalfa (Medicago sativa L.)/maize (Zea mays L.) intercropping provides a feasible way to improve yield and economic incomes in farming and pastoral areas of northeast China.

    Science.gov (United States)

    Sun, Baoru; Peng, Yi; Yang, Hongyu; Li, Zhijian; Gao, Yingzhi; Wang, Chao; Yan, Yuli; Liu, Yanmei

    2014-01-01

    Given the growing challenges to food and eco-environmental security as well as sustainable development of animal husbandry in the farming and pastoral areas of northeast China, it is crucial to identify advantageous intercropping modes and some constraints limiting its popularization. In order to assess the performance of various intercropping modes of maize and alfalfa, a field experiment was conducted in a completely randomized block design with five treatments: maize monoculture in even rows, maize monoculture in alternating wide and narrow rows, alfalfa monoculture, maize intercropped with one row of alfalfa in wide rows and maize intercropped with two rows of alfalfa in wide rows. Results demonstrate that maize monoculture in alternating wide and narrow rows performed best for light transmission, grain yield and output value, compared to in even rows. When intercropped, maize intercropped with one row of alfalfa in wide rows was identified as the optimal strategy and the largely complementary ecological niches of alfalfa and maize were shown to account for the intercropping advantages, optimizing resource utilization and improving yield and economic incomes. These findings suggest that alfalfa/maize intercropping has obvious advantages over monoculture and is applicable to the farming and pastoral areas of northeast China.

  20. Improved Biodegradable Radiation Cured Polymeric Film Prepared from Chitosan-Gelatin Blend

    Directory of Open Access Journals (Sweden)

    Zinia Nasreen

    2016-01-01

    Full Text Available The mechanical, thermal, swelling, and release properties of chitosan-gelatin (CG films have been investigated in order to verify the influence of UV and gamma radiation on the stability of the films. Thin films of chitosan and gelatin (1 : 3, w/w that were radiated with 100 krad of gamma dose showed the best performance and the TS values reached 25, 45, and 49 MPa, respectively, for chitosan, gelatin, and blend. The corresponding highest TS values were 23, 42, and 45 MPa, respectively, for 10 passes of UV radiation. The effect of radiation over gelatin, chitosan, and CG blend caused modification in the arrangement of molecules in the crystal lattice that is significant by XRD analysis. Surfaces of the films were also investigated by scanning electron microscope (SEM. Fourier transform infrared spectroscopy (FTIR studies further revealed structural changes of the films. These changes were attributed to understanding the behavior of the irradiated chitosan, gelatin, and CG blend on application of thermal energy using DSC and TGA studies, water uptake of the films in aqueous medium, and soil degradation properties to observe the best possibility for its application.

  1. Unbiased K-mer Analysis Reveals Changes in Copy Number of Highly Repetitive Sequences During Maize Domestication and Improvement

    Science.gov (United States)

    Liu, Sanzhen; Zheng, Jun; Migeon, Pierre; Ren, Jie; Hu, Ying; He, Cheng; Liu, Hongjun; Fu, Junjie; White, Frank F.; Toomajian, Christopher; Wang, Guoying

    2017-01-01

    The major component of complex genomes is repetitive elements, which remain recalcitrant to characterization. Using maize as a model system, we analyzed whole genome shotgun (WGS) sequences for the two maize inbred lines B73 and Mo17 using k-mer analysis to quantify the differences between the two genomes. Significant differences were identified in highly repetitive sequences, including centromere, 45S ribosomal DNA (rDNA), knob, and telomere repeats. Genotype specific 45S rDNA sequences were discovered. The B73 and Mo17 polymorphic k-mers were used to examine allele-specific expression of 45S rDNA in the hybrids. Although Mo17 contains higher copy number than B73, equivalent levels of overall 45S rDNA expression indicates that transcriptional or post-transcriptional regulation mechanisms operate for the 45S rDNA in the hybrids. Using WGS sequences of B73xMo17 doubled haploids, genomic locations showing differential repetitive contents were genetically mapped, which displayed different organization of highly repetitive sequences in the two genomes. In an analysis of WGS sequences of HapMap2 lines, including maize wild progenitor, landraces, and improved lines, decreases and increases in abundance of additional sets of k-mers associated with centromere, 45S rDNA, knob, and retrotransposons were found among groups, revealing global evolutionary trends of genomic repeats during maize domestication and improvement. PMID:28186206

  2. Much Improved Irrigation Use Efficiency in an Intensive Wheat-Maize Double Cropping System in the North China Plain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Crop yield and water use efficiency (WUE) in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP). A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system. Soil water depletion (△SWS)by crop generally decreased with the increase of irrigation and rainfall, while △SWS for the whole rotation was relatively stable among these irrigation treatments. High irrigations in wheat season increased initial soil moisture and △SWS for subsequent maize especially in the drought season. Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems. Grain yield decreased prior to evapotranspiration(ET) when ET reached about 300 mm for wheat, while maize showed various WUEs with similar seasonal ET. For whole rotation, WUE declined when ET exceeded about 650 mm. These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP. Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.

  3. Glycol chitosan

    DEFF Research Database (Denmark)

    Danielsen, E Thomas; Danielsen, E Michael

    2017-01-01

    Chitosan is a polycationic polysaccharide consisting of β-(1-4)-linked glucosamine units and due to its mucoadhesive properties, chemical derivatives of chitosan are potential candidates as enhancers for transmucosal drug delivery. Recently, glycol chitosan (GC), a soluble derivative of chitosan...

  4. Influence of DBD plasma pretreatment on the deposition of chitosan onto UHMWPE fiber surfaces for improvement of adhesion and dyeing properties

    Science.gov (United States)

    Ren, Yu; Ding, Zhirong; Wang, Chunxia; Zang, Chuanfeng; Zhang, Yin; Xu, Lin

    2017-02-01

    The combination treatment of dielectric barrier discharge (DBD) plasma and chitosan coatings was performed on ultrahigh molecular weight polyethylene (UHMWPE) fibers in order to improve the wettability, dyeability and adhesion properties. The properties of UHMWPE fibers coated with chitosan, after being pretreated by DBD plasma, were evaluated through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The interfacial shear strength (IFSS) between the fiber and the epoxy resin was determined using the single fiber pull-out test technique. The modified UHMWPE fibers were dyed with reactive dyes after the combined treatment. Surface wettability and dyeability were investigated by water contact angle and K/S measurement, respectively. SEM images confirmed that the chitosan was induced onto the surfaces of the UHMWPE fibers after the combined treatment. The XPS analysis showed that the oxygen and nitrogen contents of the UHMWPE fiber surfaces after the combined treatment were higher than that of the fiber modified by chitosan without DBD plasma pretreatment. Meanwhile, the UHMWPE fibers treated with combination of DBD plasma and chitosan treatment had better wettability, dyeability and adhesion property than those of the non-plasma pretreated surfaces, indicating that DBD plasma pretreatment facilitated the deposition of chitosan onto the UHMWPE surfaces.

  5. Overexpression of ARGOS Genes Modifies Plant Sensitivity to Ethylene, Leading to Improved Drought Tolerance in Both Arabidopsis and Maize.

    Science.gov (United States)

    Shi, Jinrui; Habben, Jeffrey E; Archibald, Rayeann L; Drummond, Bruce J; Chamberlin, Mark A; Williams, Robert W; Lafitte, H Renee; Weers, Ben P

    2015-09-01

    Lack of sufficient water is a major limiting factor to crop production worldwide, and the development of drought-tolerant germplasm is needed to improve crop productivity. The phytohormone ethylene modulates plant growth and development as well as plant response to abiotic stress. Recent research has shown that modifying ethylene biosynthesis and signaling can enhance plant drought tolerance. Here, we report novel negative regulators of ethylene signal transduction in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). These regulators are encoded by the ARGOS gene family. In Arabidopsis, overexpression of maize ARGOS1 (ZmARGOS1), ZmARGOS8, Arabidopsis ARGOS homolog ORGAN SIZE RELATED1 (AtOSR1), and AtOSR2 reduced plant sensitivity to ethylene, leading to enhanced drought tolerance. RNA profiling and genetic analysis suggested that the ZmARGOS1 transgene acts between an ethylene receptor and CONSTITUTIVE TRIPLE RESPONSE1 in the ethylene signaling pathway, affecting ethylene perception or the early stages of ethylene signaling. Overexpressed ZmARGOS1 is localized to the endoplasmic reticulum and Golgi membrane, where the ethylene receptors and the ethylene signaling protein ETHYLENE-INSENSITIVE2 and REVERSION-TO-ETHYLENE SENSITIVITY1 reside. In transgenic maize plants, overexpression of ARGOS genes also reduces ethylene sensitivity. Moreover, field testing showed that UBIQUITIN1:ZmARGOS8 maize events had a greater grain yield than nontransgenic controls under both drought stress and well-watered conditions.

  6. Nitrogen Deifciency Limited the Improvement of Photosynthesis in Maize by Elevated CO2 Under Drought

    Institute of Scientific and Technical Information of China (English)

    ZONG Yu-zheng; SHANGGUAN Zhou-ping

    2014-01-01

    Global environmental change affects plant physiological and ecosystem processes. The interaction of elevated CO2, drought and nitrogen (N) deficiency result in complex responses of C4 species photosynthetic process that challenge our current understanding. An experiment of maize (Zea mays L.) involving CO2 concentrations (380 or 750 µmol mol-1, climate chamber), osmotic stresses (10% PEG-6000, -0.32 MPa) and nitrogen constraints (N deficiency treated since the 144th drought hour) was carried out to investigate its photosynthesis capacity and leaf nitrogen use efficiency. Elevated CO2 could alleviate drought-induced photosynthetic limitation through increasing capacity of PEPC carboxylation (Vpmax) and decreasing stomatal limitations (SL). The N deifciency exacerbated drought-induced photosynthesis limitations in ambient CO2. Elevated CO2 partially alleviated the limitation induced by drought and N deifciency through improving the capacity of Rubisco carboxylation (Vmax) and decreasing SL. Plants with N deifciency transported more N to their leaves at elevated CO2, leading to a high photosynthetic nitrogen-use efifciency but low whole-plant nitrogen-use efifciency. The stress mitigation by elevated CO2 under N deifciency conditions was not enough to improving plant N use efifciency and biomass accumulation. The study demonstrated that elevated CO2 could alleviate drought-induced photosynthesis limitation, but the alleviation varied with N supplies.

  7. Production and characterization of chitosan/gelatin/β-TCP scaffolds for improved bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Serra, I.R.; Fradique, R.; Vallejo, M.C.S.; Correia, T.R.; Miguel, S.P.; Correia, I.J., E-mail: icorreia@ubi.pt

    2015-10-01

    Recently, bone tissue engineering emerged as a viable therapeutic alternative, comprising bone implants and new personalized scaffolds to be used in bone replacement and regeneration. In this study, biocompatible scaffolds were produced by freeze-drying, using different formulations (chitosan, chitosan/gelatin, chitosan/β-TCP and chitosan/gelatin/β-TCP) to be used as temporary templates during bone tissue regeneration. Sample characterization was performed through attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive spectroscopy analysis. Mechanical characterization and porosity analysis were performed through uniaxial compression test and liquid displacement method, respectively. In vitro studies were also done to evaluate the biomineralization activity and the cytotoxic profile of the scaffolds. Scanning electron and confocal microscopy analysis were used to study cell adhesion and proliferation at the scaffold surface and within their structure. Moreover, the antibacterial activity of the scaffolds was also evaluated through the agar diffusion method. Overall, the results obtained revealed that the produced scaffolds are bioactive and biocompatible, allow cell internalization and show antimicrobial activity against Staphylococcus aureus. Such, make these 3D structures as potential candidates for being used on the bone tissue regeneration, since they promote cell adhesion and proliferation and also prevent biofilm development at their surfaces, which is usually the main cause of implant failure. - Highlights: • Production of 3D scaffolds composed by chitosan/gelatin/β-TCP by freeze-drying for bone regeneration • Physicochemical characterization of the bone substitutes by SEM, FTIR, XRD and EDS • Evaluation of the cytotoxic profile and antibacterial activity of the 3D structures through in vitro assays.

  8. Comparative effectiveness of different Rhizobium sp. for improving growth and yield of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Ijaz Mehboob, Zahir Ahmad Zahir, Muhammad Arshad, Muhammad Khalid

    2012-05-01

    Full Text Available During the last couple of decades, it has been demonstrated that rhizobia can associate with roots of non-legumes also without forming true nodules, and can promote their growth by using one or more of the direct or indirect mechanisms of actions. This work examines the growth and yield responses of maize to inoculation with different species of rhizobia, isolated from the root nodules of chickpea (Cicer arietinum L., lentil (Lens culinaris M. and mung bean (Vigna radiata L. in pots and fields. Twenty isolates of rhizobia were isolated from root nodules each of mung bean, lentil and chickpea and were screened under axenic conditions. On the basis of their promising performance under axenic conditions, nine most efficient isolates (three from each legume host were selected, characterized and further evaluated for their growth promoting activities by conducting pot and field experiments. Results of pot experiment revealed that maximum increase in grain yield, 1000 grain weight, N, P and K uptake (up to 47.89, 54.52, 73.46, 84.66 and 59.19% by CRI28, respectively, over un-inoculated control was produced by the isolate of Mesorhizobium ciceri. Whereas, maximum improvement in rest of the parameters was caused by the isolates of Rhizobium phaseoli (i.e. fresh biomass, straw yield and root length up to 36.30% by A18, 25.46% by S6 and 81.89% by A18, respectively over un-inoculated control. Rhizobium leguminosarum isolates came out to be the least effective among the species tested. Similarly, all the selected isolates improved the growth and yield attributing parameters in fields as well but with varying capacity compared with un-inoculated control. The selected isolates of Mesorhizobium ciceri and Rhizobium phaseoli again remained superior compared to the isolates of Rhizobium leguminosarum under field conditions. The results of this study imply that rhizobium species had potential to promote growth and yield of maize but this technology should be

  9. γ-Aminobutyric Acid Imparts Partial Protection from Salt Stress Injury to Maize Seedlings by Improving Photosynthesis and Upregulating Osmoprotectants and Antioxidants

    Science.gov (United States)

    Wang, Yongchao; Gu, Wanrong; Meng, Yao; Xie, Tenglong; Li, Lijie; Li, Jing; Wei, Shi

    2017-01-01

    γ-Aminobutyric acid (GABA) has high physiological activity in plant stress physiology. This study showed that the application of exogenous GABA by root drenching to moderately (MS, 150 mM salt concentration) and severely salt-stressed (SS, 300 mM salt concentration) plants significantly increased endogenous GABA concentration and improved maize seedling growth but decreased glutamate decarboxylase (GAD) activity compared with non-treated ones. Exogenous GABA alleviated damage to membranes, increased in proline and soluble sugar content in leaves, and reduced water loss. After the application of GABA, maize seedling leaves suffered less oxidative damage in terms of superoxide anion (O2·−) and malondialdehyde (MDA) content. GABA-treated MS and SS maize seedlings showed increased enzymatic antioxidant activity compared with that of untreated controls, and GABA-treated MS maize seedlings had a greater increase in enzymatic antioxidant activity than SS maize seedlings. Salt stress severely damaged cell function and inhibited photosynthesis, especially in SS maize seedlings. Exogenous GABA application could reduce the accumulation of harmful substances, help maintain cell morphology, and improve the function of cells during salt stress. These effects could reduce the damage to the photosynthetic system from salt stress and improve photosynthesis and chlorophyll fluorescence parameters. GABA enhanced the salt tolerance of maize seedlings. PMID:28272438

  10. Stabilization of porous chitosan improves the performance of its association with platelet-rich plasma as a composite scaffold.

    Science.gov (United States)

    Shimojo, A A M; Perez, A G M; Galdames, S E M; Brissac, I C S; Santana, M H A

    2016-03-01

    This study offers innovative perspectives for optimizing of scaffolds based on correlation structure-function aimed the regenerative medicine. Thus, we evaluated in vitro performance of stabilized porous chitosan (SPCHTs) associated with activated platelet-rich plasma (aP-PRP) as a composite scaffold for the proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells (h-AdMSCs). The porous structure of chitosan (PCHT) was prepared similarly to solid sponges by controlled freezing (-20 °C) and lyophilization of a 3% (w/v) chitosan solution. Stabilization was performed by treating the PCHT with sodium hydroxide (TNaOH), an ethanol series (TEtOH) or by crosslinking with tripolyphosphate (CTPP). The aP-PRP was obtained from the controlled centrifugation of whole blood and activated with autologous serum and calcium. Imaging of the structures showed fibrin networks inside and on the surface of SPCHTs as a consequence of electrostatic interactions. SPCHTs were non-cytotoxic, and the porosity, pore size and Young's modulus were approximately 96%, 145 μm and 1.5 MPa for TNaOH and TEtOH and 94%, 110 μm and 1.8 MPa for CTPP, respectively. Stabilization maintained the integrity of the SPCHTs for at least 10 days of cultivation. SPCHTs showed controlled release of the growth factors TGF-β1 and PDGF-AB. Although generating different patterns, all of the stabilization treatments improved the proliferation of seeded h-AdMSCs on the composite scaffold compared to aP-PRP alone, and differentiation of the composite scaffold treated with TEtOH was significantly higher than for non-stabilized PCHT. We conclude that the composite scaffolds improved the in vitro performance of PRP and have potential in regenerative medicine.

  11. Utilization of maize cob biochar and rice husk charcoal as soil amendments for improving acid soil fertility and productivity

    Directory of Open Access Journals (Sweden)

    Nurhidayati

    2014-10-01

    Full Text Available The decline in soil fertility in agricultural land is a major problem that causes a decrease in the production of food crops. One of the causes of the decline in soil fertility is declining soil pH that caused the decline in the availability of nutrients in the soil. This study aimed to assess the influence of alternative liming materials derived from maize cob biochar and rice husk charcoal compared to conventional lime to improve soil pH, soil nutrient availability and maize production. The experiment used a factorial complete randomized design which consisting of two factors. The first factor is the type of soil amendment which consists of three levels (calcite lime, rice husk charcoal and cob maize biochar. The second factor is the application rates of the soil amendment consisted of three levels (3, 6 and 9 t/ha and one control treatment (without soil amendment. The results of this study showed that the application of various soil amendment increased soil pH, which the pH increase of the lime application was relatively more stable over time compared to biochar and husk charcoal. The average of the soil pH increased for each soil amendment by 23% (lime, 20% (rice husk charcoal and 23% (biochar as compared with control. The increase in soil pH can increase the availability of soil N, P and K. The greatest influence of soil pH on nutrient availability was shown by the relationship between soil pH and K nutrient availability with R2 = 0.712, while for the N by R2 = 0.462 and for the P by R2 = 0.245. The relationship between the availability of N and maize yield showed a linear equation. While the relationship between the availability of P and K with the maize yield showed a quadratic equation. The highest maize yield was found in the application of biochar and rice husk charcoal with a dose of 6-9 t/ha. The results of this study suggested that biochar and husk charcoal could be used as an alternative liming material in improving acid soil

  12. Research Status on Drought Performance Improvement of Maize%提高玉米耐旱、抗旱性能的研究现状

    Institute of Scientific and Technical Information of China (English)

    梁鸡保; 龚靖世; 李志军; 李琛

    2012-01-01

    As one of major food crops in China, maize production is extremely affected by drought. Improve the drought resistance and tolerance of maize is imperative. The effect of drought stress on maize yield at different growth periods was in-trodused. And the research progress on drought performance improvement of maize was summarized.%作为中国主要的粮食作物之一,玉米产量受干旱影响极其严重,提高玉米的耐旱、抗旱性能势在必行.在介绍干旱胁迫在不同时期对玉米产量影响的基础上,综述了目前在玉米耐旱、抗旱性能提高方面的研究现状,并进行了展望.

  13. Trehalose accumulation in Azospirillum brasilense improves drought tolerance and biomass in maize plants.

    Science.gov (United States)

    Rodríguez-Salazar, Julieta; Suárez, Ramón; Caballero-Mellado, Jesús; Iturriaga, Gabriel

    2009-07-01

    Bacteria of the genus Azospirillum increase the grain yield of several grass crops. In this work the effect of inoculating maize plants with genetically engineered Azospirillum brasilense for trehalose biosynthesis was determined. Transformed bacteria with a plasmid harboring a trehalose biosynthesis gene-fusion from Saccharomyces cerevisiae were able to grow up to 0.5 M NaCl and to accumulate trehalose, whereas wild-type A. brasilense did not tolerate osmotic stress or accumulate significant levels of the disaccharide. Moreover, 85% of maize plants inoculated with transformed A. brasilense survived drought stress, in contrast with only 55% of plants inoculated with the wild-type strain. A 73% increase in biomass of maize plants inoculated with transformed A. brasilense compared with inoculation with the wild-type strain was found. In addition, there was a significant increase of leaf and root length in maize plants inoculated with transformed A. brasilense. Therefore, inoculation of maize plants with A. brasilense containing higher levels of trehalose confers drought tolerance and a significant increase in leaf and root biomass. This work opens the possibility that A. brasilense modified with a chimeric trehalose biosynthetic gene from yeast could increase the biomass, grain yield and stress tolerance in other relevant crops.

  14. Improving the stability of chitosan-gelatin-based hydrogels for cell delivery using transglutaminase and controlled release of doxycycline.

    Science.gov (United States)

    Tormos, Christian J; Abraham, Carol; Madihally, Sundararajan V

    2015-12-01

    Although local cell delivery is an option to repair tissues, particularly using chitosan-based hydrogels, significant attrition of injected cells prior to engraftment has been a problem. To address this problem, we explored the possibility of stabilizing the chitosan-gelatin (CG) injectable hydrogels using (1) controlled release of doxycycline (DOX) to prevent premature degradation due to increased gelatinase activity (MMP-2 and MMP-9), and (2) transglutaminase (TG) to in situ cross-link gelatin to improve the mechanical stability. We prepared DOX-loaded PLGA nanoparticles, loaded into the CG hydrogels, measured DOX release for 5 days, and modeled using a single-compartmental assumption. Next, we assessed the influence of TG and DOX on hydrogel compression properties by incubating hydrogels for 7 days in PBS. We evaluated the effect of these changes on retention of fibroblasts and alterations in MMP-2/MMP-9 activity by seeding 500,000 fibroblasts for 5 days. These results showed that 90 % of DOX released from cross-linked CG hydrogels after 4 days, unlike CG hydrogels where 90 % of DOX was released within the first day. Addition of TG enhanced the CG hydrogel stability significantly. More than 60 % of seeded fibroblasts were recovered from the CG-TG hydrogels at day 5, unlike 40 % recovered from CG-hydrogels. Inhibition of MMP-2/MMP-9 were observed. In summary, controlled release of DOX from CG hydrogels cross-linked with TG shows a significant potential as a carrier for cell delivery.

  15. Identification and genetic characterization of maize cell wall variation for improved biorefinery feedstock characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Markus [UC Berkeley; Hake, Sarah [USDA Albany

    2013-10-31

    The objectives of this program are to 1) characterize novel maize mutants with altered cell walls for enhanced biorefinery characteristics and 2) find quantitative trait loci (QTLs) related to biorefinery characteristics by taking advantage of the genetic diversity of maize. As a result a novel non-transgenic maize plant (cal1) has been identified, whose stover (leaves and stalk) contain more glucan in their walls leading to a higher saccharification yield, when subjected to a standard enzymatic digestion cocktail. Stacking this trait with altered lignin mutants yielded evene higher saccharification yields. Cal-1 mutants do not show a loss of kernel and or biomass yield when grown in the field . Hence, cal1 biomass provides an excellent feedstock for the biofuel industry.

  16. Improvement of corrosion resistance and antibacterial effect of NiTi orthopedic materials by chitosan and gold nanoparticles

    Science.gov (United States)

    Ahmed, Rasha A.; Fadl-allah, Sahar A.; El-Bagoury, Nader; El-Rab, Sanaa M. F. Gad

    2014-02-01

    Biocomposite consists of gold nanoparticles (AuNPs) and a natural polymer as Chitosan (CS) was electrodeposited over NiTi alloy to improve biocompatibility, biostability, surface corrosion resistance and antibacterial effect for orthopedic implantation. The forming process and surface morphology of this biocomposite coats over NiTi alloy were studied. The results showed that the nm-scale gold particles were embedded in the composite forming compact, thick and smooth coat. Elemental analysis revealed significant less Ni ion release from the coated NiTi alloy compared with the uncoated one by 20 fold. Furthermore, the electrochemical corrosion measurements indicated that AuNPs/CS composite coat was effective for improving corrosion resistance in different immersion times and at all pH values, which suggests that the coated NiTi alloys have potential for orthopedic applications. Additionally, the efficiencies of the biocomposite coats for inhibiting bacterial growth indicate high antibacterial effect.

  17. Superparamagnetic iron oxide/chitosan core/shells for hyperthermia application: Improved colloidal stability and biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Patil, R.M.; Shete, P.B.; Thorat, N.D.; Otari, S.V. [Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416006, MS (India); Barick, K.C.; Prasad, A.; Ningthoujam, R.S. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, MS (India); Tiwale, B.M. [Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416006, MS (India); Pawar, S.H., E-mail: pawar_s_h@yahoo.com [Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416006, MS (India)

    2014-04-15

    Superparamagnetic magnetite nanoparticles are of great interest due to their potential biomedical applications. In the present investigation, Fe{sub 3}O{sub 4} magnetic nanoparticles were prepared by alkaline precipitation using ferrous chloride as the sole source. An amphiphilic polyelectrolyte with the property of biocompatibility and functional carboxyl groups was used as a stabilizer to prepare a well-dispersed suspension of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles. The final material composed of Fe{sub 3}O{sub 4} core and chitosan (CH) shell was produced. The amino groups of CH coated on Fe{sub 3}O{sub 4} nanoparticles were further cross linked using glutaraldehyde (GLD) for stable coating. FTIR spectra, XPS and TGA confirmed the coating of CH/GLD on the surface of Fe{sub 3}O{sub 4} nanoparticles. XRD patterns indicate the pure phase Fe{sub 3}O{sub 4} with a spinel structure. The nanoparticles were superparamagnetic at room temperature with saturation magnetization values for bare and coated nanoparticles which were 51.68 emu/g and 48.60 emu/g, respectively. Zeta potential values showed higher colloidal stability of coated nanoparticles than the bare one. Cytotoxicity study up to 2 mg mL{sup −1} concentration showed no drastic change in cell viability of nanoparticles after coating. Also, coated nanoparticles showed increased SAR value, making them suitable for hyperthermia therapy application. - Highlights: • Fe{sub 3}O{sub 4} nanoparticles were synthesized from FeCl{sub 2} as the sole source by alkaline precipitation. • Coating of Fe{sub 3}O{sub 4} nanoparticles was done with chitosan by simple ultrasonication. • Chitosan cross-linked with glutaraldehyde. • High colloidal stability was observed. • Increased SAR value and least cytotoxicity were observed.

  18. Development and characterization of an edible composite film based on chitosan and virgin coconut oil with improved moisture sorption properties.

    Science.gov (United States)

    Binsi, P K; Ravishankar, C N; Srinivasa Gopal, T K

    2013-04-01

    An edible composite film was prepared from an emulsion system based on chitosan and virgin coconut oil (VCO). The effect of incorporation of VCO was evaluated at various concentrations and the optimum concentration was chosen based on resultant changes in the properties of the film. Addition of VCO in film forming solution resulted in increase in film thickness and marginal reduction in film transparency. Compatibility of VCO with chitosan was better at lower concentration of VCO as indicated by the microstructure of composite film in scanning electron micrographs. Phase separation was evident at higher level of oil incorporation and the optimal oil/chitosan ratio was determined to be at 0.5 to 1 mL/g chitosan. Furthermore, chemical interaction took place between VCO and chitosan as revealed by Fourier transform infrared spectroscopy data. Even though control chitosan films exhibited superior gas barrier properties, composite film with optimum VCO concentration revealed better mechanical and moisture sorption properties.

  19. Improving weed management and crop productivity in maize systems in Zimbabwe

    NARCIS (Netherlands)

    Mashingaidze, A.B.

    2004-01-01

    Keywords: Intercropping, narrow planting, precise fertilizer placement, radiation interception, leaf stripping, detasselling, Land Equivalent Ratio, maize, pumpkin, dry beans, reduced herbicide dosagesIn the tropics, weeds cause more

  20. Towards improved nitrogen management in silage maize production on sandy soils.

    NARCIS (Netherlands)

    Schroder, J.J.

    1998-01-01

    Maize has become a highly appreciated crop in Dutch dairy farming during the last 25 years. The current cropping technique, however, is associated with a low recovery of soil mineral nitrogen (N) and serious losses of N to the environment. This gave rise to the research described in this thesis whic

  1. Enhancing Biological Wastewater Treatment with Chitosan

    Institute of Scientific and Technical Information of China (English)

    陈亮; 陈东辉; 朱珺

    2003-01-01

    Chitin and chitosan have been applied to biological wastewater treatment.From a number of parallel comparison experiments,it can be concluded that the application of chitin and chitosan can both enhance the biological treatment,besides which chitosan is more efficient than chitin.The study on the enhancement mechanism reveals the difference between the two additives:chitosan improves the sludge structure and settlibility,while chitin acts as a kind of carrier for microorganism in the biological treatment system.

  2. Folic Acid-Chitosan Conjugated Nanoparticles for Improving Tumor-Targeted Drug Delivery

    Directory of Open Access Journals (Sweden)

    Huijuan Song

    2013-01-01

    Full Text Available Objective. To prepare folic acid-chitosan conjugated nanoparticles (FA-CS NPs and evaluate their targeting specificity on tumor cells. Methods. Chitosan (CS NPs were prepared by ionic cross linking method, and folic acid (FA was conjugated with CS NPs by electrostatic interaction. The properties of NPs were investigated, and doxorubicin hydrochloride (Dox as a model drug was encapsulated for investigating drug release pattern in vitro. The cytotoxicity and cellular uptake of FA-CS NPs were also investigated. Results. The results reveal that the obtained FA-CS NPs were monodisperse nanoparticles with suitable average size and positive surface charge. Dox was easily loaded into FA-CS NPs, and the release pattern showed a long and biphasic drug release. Noticeable phagocytosis effect was observed in the presence of rhodamine B-labeled FA-CSNPs when incubating with the folate receptor-positive SMMC-7221 cells. Conclusion. Compared with the unmodified CS NPs, FA-CS NPs showed much higher cell uptaking ability due to the known folate-receptor mediated endocytosis. FA-CS NPs provide a potential way to enhance the using efficiency of antitumor drug by folate receptor mediated targeting delivery.

  3. Flavone-rich maize: An opportunity to improve the nutritional value of an important commodity crop

    Directory of Open Access Journals (Sweden)

    Maria Isabel Casas

    2014-09-01

    Full Text Available Agricultural outputs have resulted in food production continuously expanding. Satisfying the needs of a fast growing human population, higher yields, more efficient food processing, and food esthetic value, resulted in crop varieties with higher caloric intake but lacking many phytochemicals important for plant protection and adequate human nutrition. The increasing incidence of chronic diseases such as obesity, diabetes and cardiovascular diseases, combined with social disparity worldwide prompted the interest in developing enhanced crops that can simultaneously address the two sides of the current malnutrition sword, increasing yield while providing added nutritional value. Flavones, phytochemicals associated with the beneficial effects of the Mediterranean diet, have potent anti-inflammatory and anti-carcinogenic activities. However, many Mediterranean diet-associated vegetables are inaccessible, or lowly consumed, in many parts of the world. Maize is the most widely grown cereal crop, yet most lines used for hybrid maize production lack flavones. As a first step towards a sustainable strategy to increasing the nutritional value of maize-based diets, we investigated the accumulation and chemical properties of flavones in maize seeds of defined genotypes. We show that the pericarps of the P1-rr genotype accumulate flavones at levels comparable to those present in some flavone-rich vegetables, and are mostly present in their C- and O-glycosylated forms. Some of these glycosides can be readily converted into the corresponding more active health beneficial aglycones during food processing. Our results provide evidence that nutritionally beneficial flavones could be re-introduced into elite lines to increase the dietary benefits of maize.

  4. Flavone-rich maize: an opportunity to improve the nutritional value of an important commodity crop.

    Science.gov (United States)

    Casas, María I; Duarte, Silvia; Doseff, Andrea I; Grotewold, Erich

    2014-01-01

    Agricultural outputs have resulted in food production continuously expanding. To satisfy the needs of a fast growing human population, higher yields, more efficient food processing, and food esthetic value, new crop varieties with higher caloric intake have and continue to be developed, but which lack many phytochemicals important for plant protection and adequate human nutrition. The increasing incidence of chronic diseases such as obesity, diabetes and cardiovascular diseases, combined with social disparity worldwide prompted the interest in developing enhanced crops that can simultaneously address the two sides of the current malnutrition sword, increasing yield while providing added nutritional value. Flavones, phytochemicals associated with the beneficial effects of the Mediterranean diet, have potent anti-inflammatory and anti-carcinogenic activities. However, many Mediterranean diet-associated vegetables are inaccessible, or lowly consumed, in many parts of the world. Maize is the most widely grown cereal crop, yet most lines used for hybrid maize production lack flavones. As a first step toward a sustainable strategy to increasing the nutritional value of maize-based diets, we investigated the accumulation and chemical properties of flavones in maize seeds of defined genotypes. We show that the pericarps of the P1-rr genotype accumulate flavones at levels comparable to those present in some flavone-rich vegetables, and are mostly present in their C- and O-glycosylated forms. Some of these glycosides can be readily converted into the corresponding more active health beneficial aglycones during food processing. Our results provide evidence that nutritionally beneficial flavones could be re-introduced into elite lines to increase the dietary benefits of maize.

  5. Evaluation of Chitosan-Starch-Based Edible Coating To Improve the Shelf Life of Bod Ljong Cheese.

    Science.gov (United States)

    Mei, Jun; Guo, Qizhen; Wu, Yan; Li, Yunfei

    2015-07-01

    The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to improve the quality of Bod ljong cheese throughout 25 days of storage. Coatings were prepared using chitosan, water chestnut starch, and glycerol as a base matrix, together with several combinations of antimicrobial substances: Cornus officinalis fruit extract (COFE), pine needle essential oil (PNEO), and nisin. Application of coating on cheese decreased water loss, lipid oxidation, changes in headspace gas composition, and color. Moreover, the edible coatings with COFE or PNEO had increased antimicrobial activity and did not permit growth of microorganisms. COFE and PNEO are manufactured from food-grade materials so they can be consumed as an integral part of the cheese, which represents a competitive advantage over nonedible coatings.

  6. Improving stability and biocompatibility of alginate/chitosan microcapsule by fabricating bi-functional membrane.

    Science.gov (United States)

    Zheng, Guoshuang; Liu, Xiudong; Wang, Xiuli; Chen, Li; Xie, Hongguo; Wang, Feng; Zheng, Huizhen; Yu, Weiting; Ma, Xiaojun

    2014-05-01

    Cell encapsulation technology holds promise for the cell-based therapy. But poor mechanical strength and biocompatibility of microcapsule membrane are still obstacles for the clinical applications. A novel strategy is presented to prepare AC₁ C₂ A microcapsules with bi-functional membrane (that is, both desirable biocompatibility and membrane stability) by sequentially complexing chitosans with higher deacetylation degree (C₁) and lower deacetylation degree (C₂) on alginate (A) gel beads. Both in vitro and in vivo evaluation of AC₁C₂ A microcapsules demonstrate higher membrane stability and less cell adhesion, because the introduction of C₂ increases membrane strength and decreases surface roughness. Moreover, diffusion test of AC₁C₂ A microcapsules displays no inward permeation of IgG protein suggesting good immunoisolation function. The results demonstrate that AC₁C₂ A microcapsules with bi-functional membrane could be a promising candidate for microencapsulated cell implantation with cost effective usage of naturally biocompatible polysaccharides.

  7. Improving aerobic stability and biogas production of maize silage using silage additives.

    Science.gov (United States)

    Herrmann, Christiane; Idler, Christine; Heiermann, Monika

    2015-12-01

    The effects of air stress during storage, exposure to air at feed-out, and treatment with silage additives to enhance aerobic stability on methane production from maize silage were investigated at laboratory scale. Up to 17% of the methane potential of maize without additive was lost during seven days exposure to air on feed-out. Air stress during storage reduced aerobic stability and further increased methane losses. A chemical additive containing salts of benzoate and propionate, and inoculants containing heterofermentative lactic acid bacteria were effective to increase aerobic stability and resulted in up to 29% higher methane yields after exposure to air. Exclusion of air to the best possible extent and high aerobic stabilities should be primary objectives when ensiling biogas feedstocks.

  8. Conversion to No-Till Improves Maize Nitrogen Use Efficiency in a Continuous Cover Cropping System

    Science.gov (United States)

    Habbib, Hazzar; Verzeaux, Julien; Nivelle, Elodie; Roger, David; Lacoux, Jérôme; Catterou, Manuella; Hirel, Bertrand; Dubois, Frédéric; Tétu, Thierry

    2016-01-01

    A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to nitrogen (N) use efficiency and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. Moreover, we observed that grain yield and grain N content were higher under no-till conditions only when N fertilizers were applied. Thus, agronomic practices based on continuous no-till appear to be a promising for increasing N use efficiency in maize. PMID:27711154

  9. Strategies to improve low copy transgenic events in Agrobacterium-mediated transformation of maize.

    Science.gov (United States)

    Sivamani, Elumalai; Li, Xianggan; Nalapalli, Samson; Barron, Yoshimi; Prairie, Anna; Bradley, David; Doyle, Michele; Que, Qiudeng

    2015-12-01

    Transgenic plants containing low copy transgene insertion free of vector backbone are highly desired for many biotechnological applications. We have investigated two different strategies for increasing the percentage of low copy events in Agrobacterium-mediated transformation experiments in maize. One of the strategies is to use a binary vector with two separate T-DNAs, one T-DNA containing an intact E.coli manA gene encoding phosphomannose isomerase (PMI) as selectable marker gene cassette and another T-DNA containing an RNAi cassette of PMI sequences. By using this strategy, low copy transgenic events containing the transgenes were increased from 43 to 60 % in maize. An alternate strategy is using selectable marker gene cassettes containing regulatory or coding sequences derived from essential plant genes such as 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) or MADS box transcription factor. In this paper we demonstrate that higher percentage of low copy transgenic events can be obtained in Agrobacterium-mediated maize transformation experiments using both strategies. We propose that the above two strategies can be used independently or in combination to increase transgenic events that contain low copy transgene insertion in Agrobacterium-mediated transformation experiments.

  10. Six month-duration Tephrosia vogelii Hook. f. and Tithonia diversifolia (Hemsl. A. Gray planted-fallows for improving maize production in Kenya

    Directory of Open Access Journals (Sweden)

    Gachene C.K.K.

    2008-01-01

    Full Text Available An experiment including planted Tephrosia vogelii and Tithonia diversifolia fallow species and natural fallow was conducted at Maseno, Kenya, for assessing whether these fallows grown on a nutrient depleted land could produce sufficient green manure in six month period, whether their biomass retained on the same plots or transferred to continuously cropped plots with or without added P fertiliser could increase yield of consecutive maize crops and whether it is useful to regularly repeat these fallows on same plots. First fallow was established in randomized complete blocks with three replicates. At harvesting, biomass was recorded, then either incorporated in situ or transferred to continuous cropped plots split with and without added P fertiliser and monitored for the effect in improving consecutive maize crops. The second fallow was managed on this split plot design. The two-planted shrubs fallows produced more than 9 Mg total dry biomass and accumulated 154 to 234 kg N.ha-1, which were significantly higher compared to the production in the natural fallow. The shrubs were also superior to natural fallow for P accumulation (5-22 kg versus 2 kg.ha-1. The aboveground dry biomass harvested from planted T. vogelii and T. diversifolia and either incorporated in situ or transferred into continuously cropped plots increased maize yields by 2.5 folds compared to the unmanured crop, the control. Supplementing the organic materials with an additional 20 kg P inorganic fertilizer increased the 1st maize yield by about 40%. Productivity in the plots with T. vogelii or T. diversifolia aboveground biomass removal was low for the subsequent fallow and maize crops when compared to the performance in plots where biomass was incorporated. To achieve sustained yields of maize in depleted soils requires regular improved fallowing at least one season alternating with one season maize, and additional P inputs.

  11. Modiifed fertilization management of summer maize (Zea mays L.) in northern China improves grain yield and efifciency of nitrogen use

    Institute of Scientific and Technical Information of China (English)

    CHENG Yi; ZHAO Jie; LIU Zhen-xiang; HUO Zhi-jin; LIU Peng; DONG Shu-ting; ZHANG Ji-wang; ZHAO Bin

    2015-01-01

    Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited. Modiifed fertilization management and planting density are efifcient methods for increasing crop yield. Field experiments were designed to investigate the inlfuence of modiifed fertilization management and planting density on grain yield and nitrogen use efifciency of the popular maize variety Zhengdan 958, in four treatments including local farmer’s practice (FP), high-yielding and high efifciency cultivation (HH), super high-yielding cultivation (SH), and the control (CK). Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China. Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efifciency by increasing planting density and postponing the supplementary application of fertilizers. However, with an increase in planting density, the demand of N increased along with grain yield. Due to the input of too much N fertilizer, the efifciency of N use in SH was low. Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and ifnal y achieve synchronization between high yield and high N efifciency in fertile soils. However, in situations where soil fertility is low, achieving high yield and high N use efifciency in maize wil likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-ifl ing stage.

  12. Superparamagnetic iron oxide/chitosan core/shells for hyperthermia application: Improved colloidal stability and biocompatibility

    Science.gov (United States)

    Patil, R. M.; Shete, P. B.; Thorat, N. D.; Otari, S. V.; Barick, K. C.; Prasad, A.; Ningthoujam, R. S.; Tiwale, B. M.; Pawar, S. H.

    2014-04-01

    Superparamagnetic magnetite nanoparticles are of great interest due to their potential biomedical applications. In the present investigation, Fe3O4 magnetic nanoparticles were prepared by alkaline precipitation using ferrous chloride as the sole source. An amphiphilic polyelectrolyte with the property of biocompatibility and functional carboxyl groups was used as a stabilizer to prepare a well-dispersed suspension of superparamagnetic Fe3O4 nanoparticles. The final material composed of Fe3O4 core and chitosan (CH) shell was produced. The amino groups of CH coated on Fe3O4 nanoparticles were further cross linked using glutaraldehyde (GLD) for stable coating. FTIR spectra, XPS and TGA confirmed the coating of CH/GLD on the surface of Fe3O4 nanoparticles. XRD patterns indicate the pure phase Fe3O4 with a spinel structure. The nanoparticles were superparamagnetic at room temperature with saturation magnetization values for bare and coated nanoparticles which were 51.68 emu/g and 48.60 emu/g, respectively. Zeta potential values showed higher colloidal stability of coated nanoparticles than the bare one. Cytotoxicity study up to 2 mg mL-1 concentration showed no drastic change in cell viability of nanoparticles after coating. Also, coated nanoparticles showed increased SAR value, making them suitable for hyperthermia therapy application.

  13. Altered Lignin Biosynthesis Improves Cellulosic Bioethanol Production in Transgenic Maize Plants Down-Regulated for Cinnamyl Alcohol Dehydrogenase

    Institute of Scientific and Technical Information of China (English)

    Silvia Fornalé; Pere Puigdomènech; Joan Rigau; David Caparrós-Ruiz; Montserrat Capellades; Antonio Encina; Kan Wang; Sami Irar; Catherine Lapierre; Katia Ruel; Jean-Paul Joseleau; Jordi Berenguer

    2012-01-01

    Cinnamyl alcohol dehydrogenase(CAD)is a key enzyme involved in the last step of monolignol biosynthesis.The effect of CAD down-regulation on lignin production was investigated through a transgenic approach in maize.Transgenic CAD-RNAi plants show a different degree of enzymatic reduction depending on the analyzed tissue and show alterations in cell wall composition.Cell walls of CAD-RNAi stems contain a lignin polymer with a slight reduction in the S-to-G ratio without affecting the total lignin content.In addition,these cell walls accumulate higher levels of cellulose and arabinoxylans.In contrast,cell walls of CAD-RNAi midribs present a reduction in the total lignin content and of cell wall polysaccharides.In vitro degradability assays showed that,although to a different extent,the changes induced by the repression of CAD activity produced midribs and stems more degradable than wild-type plants.CAD-RNAi plants grown in the field presented a wild-type phenotype and produced higher amounts of dry biomass.Cellulosic bioethanol assays revealed that CAD-RNAi biomass produced higher levels of ethanol compared to wild-type,making CAD a good target to improve both the nutritional and energetic values of maize lignocellulosic biomass.

  14. IMPROVEMENT OF RESPONSE TO LOW WATER AVAILABILITY IN MAIZE PLANTS INOCULATED WITH SELECTED RHIZOSPHERIC MICROBIAL CONSORTIA UNDER DIFFERENT IRRIGATION REGIMES

    Directory of Open Access Journals (Sweden)

    Eligio Malusà

    2014-01-01

    Full Text Available Low water availability for agriculture is a rising problem in temperate countries. The effect of two different rhizospheric microbial consortia on the tolerance to water deficiency of maize was evaluated under controlled watering regimes. One consortium was a mixture of arbuscular mycorrhizal fungi and rhizospheric bacteria isolated under osmotic stress selective pressure; the other consortium was a commercial product. A higher tolerance of plants to water deficiency was observed when roots were inoculated with microbial consortia. Plant gas exchange parameters were positively affected by inoculation, and a improvements of the leaves mineral nutrients content and of the biomass yield were also recorded. The positive effect should be ascribed to an increased roots development more than to an increased uptake from extraradical mycorrhizal hyphae. The use of microbial inoculants appears to be a suitable practice to improve the crop performances under low water availability.

  15. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    Science.gov (United States)

    Gartner, Hunter; Li, Yana; Almenar, Eva

    2015-03-01

    The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41-35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228-303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  16. Improvement to Maize Growth Caused by Biochars Derived From Six Feedstocks Prepared at Three Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    LUO Yu; JIAO Yu-jie; ZHAO Xiao-rong; LI Gui-tong; ZHAO Li-xin; MENG Hai-bo

    2014-01-01

    Biochar is increasingly proposed as a soil amendment, with reports of benefits to soil physical, chemical and biological properties. In this study, different biochars were produced from 6 feedstocks, including straw and poultry manure, at 3 pyrolysis temperatures (200, 300 and 500°C) and then added separately to a calcareous soil. Their effects on soil properties and maize growth were evaluated in a pot experiment. The biochars derived from crop straw had much higher C but smaller N concentrations than those derived from poultry manure. Carbon concentrations, pH and EC values increased with increasing pyrolysis temperature. Biochar addition resulted in increases in mean maize dry matter of 12.73%and NPK concentrations of 30, 33 and 283%, respectively. Mean soil pH values were increased by 0.45 units. The biochar-amended soils had 44, 55, 254 and 537%more organic C, total N, Olsen-P and available K, respectively, than the control on average. Both feedstocks and pyrolysis temperature determined the characteristics of the biochar. Biochars with high mineral concentrations may act as mineral nutrient supplements.

  17. Encapsulation of selenium in chitosan nanoparticles improves selenium availability and protects cells from selenium-induced DNA damage response

    Science.gov (United States)

    Selenium, an essential mineral, plays important roles in optimizing human health. Chitosan is an effective, naturally oriented material for synthesizing nanoparticles with polyanions and exhibit preferable properties such as biocompatibility, biodegradation and resistance to certain enzymes. We have...

  18. Improving the controlled delivery formulations of caffeine in alginate hydrogel beads combined with pectin, carrageenan, chitosan and psyllium.

    Science.gov (United States)

    Belščak-Cvitanović, Ana; Komes, Draženka; Karlović, Sven; Djaković, Senka; Spoljarić, Igor; Mršić, Gordan; Ježek, Damir

    2015-01-15

    Alginate-based blends consisting of carrageenan, pectin, chitosan or psyllium husk powder were prepared for assessment of the best formulation aimed at encapsulation of caffeine. Alginate-pectin blend exhibited the lowest viscosity and provided the smallest beads. Alginate-psyllium husk blend was characterised with higher viscosity, yielding the largest bead size and the highest caffeine encapsulation efficiency (83.6%). The release kinetics of caffeine indicated that the porosity of alginate hydrogel was not reduced sufficiently to retard the diffusion of caffeine from the beads. Chitosan coated alginate beads provided the most retarded release of caffeine in water. Morphological characteristics of beads encapsulating caffeine were adversely affected by freeze drying. Bitterness intensity of caffeine-containing beads in water was the lowest for alginate-psyllium beads and chitosan coated alginate beads. Higher sodium alginate concentration (3%) for production of hydrogel beads in combination with psyllium or chitosan coating would present the most favourable carrier systems for immobilization of caffeine.

  19. Role of chitosan in improving salinity resistance through some morphological and physiological characteristics in fenugreek (Trigonella foenum-graecum L.

    Directory of Open Access Journals (Sweden)

    H. Mosapour Yahyaabadi

    2016-06-01

    Full Text Available Soil salinity is a serious environmental problem that has negative impacts on growth and production of plants. On the other hand, application of chitosan has recently been increased to enhance the resistance to different stresses, such as salinity. In order to study the effect of chitosan seed-priming on alleviation of salinity stress in fenugreek (Trigonella foenum-graecum L. a factorial experiment, based on completely randomized design with three replications, was conducted in 2014 in the Research Greenhouse of University of Zabol. Chitosan pretreatment, taken as the first factor, was applied at three levels (0, 0.5 and 1 g/l and sodium chloride (NaCl was the second factor at four levels (0, 50, 150 and 250 mM. Before planting, the seeds were soaked for 6 hours in the chitosan solutions. NaCl was applied to the plants by irrigation water (after 2-leaf stage, with 3-day intervals. Results indicated that increasing salinity stress reduced growth characteristics, content of photosynthetic pigments, leaf relative water content, chlorophyll index and increased the amount of anthocyanin and proline. Seed-pretreatment by application of 0.5 mg/L chitosan, under salinity stress, increased plant dry weight, length of stem and roots, and leaf relative water content, as compared to the control treatment. In addition, under the salinity level of 250 mM, application of 1 g/L chitosan increased chlorophyll a, chlorophyll b and carotenoids content by 43.7, 65.4 and 28 percent, respectively, as compared to the control treatment. The highest amount of anthocyanin was found in the 1 g/L chitosan treatment. In general, these results suggested that in salt-affected areas, seed pretreatment by application of chitosan could be utilized efficiently for reducing the salinity stress on leaf relative water content and photosynthetic pigments, and better growth and stablishment of fenugreek plant.

  20. Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment

    OpenAIRE

    Abebe, Lydia S.; Xinyu Chen; Sobsey, Mark D.

    2016-01-01

    The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which...

  1. Prof. Wang Jie Met with the Chair of Board of Trustees and the Director General of International Maize and Wheat Improvement Center

    Institute of Scientific and Technical Information of China (English)

    Zhang Yongtao

    2007-01-01

    @@ On April 10, 2007, Prof. Wang Jie, Vice President of NSFC, met with the delegation from International Maize and Wheat Improvement Center (CIMMYT), headed by its Chair of Board of Trustees Prof. Lene Lange and the Director General Prof. Masa Iwanaga.

  2. Improving the efficiency of use of small amounts of nitrogen and phosphorus fertilizer on smallholders maize in Central Malawi

    NARCIS (Netherlands)

    Kamanga, B.C.G.; Waddington, S.R.; Almekinders, C.J.M.; Giller, K.E.

    2014-01-01

    Mineral fertiliser is a scarce input for smallholder maize farmers in Malawi. A recent provision of small amounts of subsidised fertilisers by government programmes to farmers throughout Malawi has increased fertiliser access and raised maize production, but fertiliser management and yield responses

  3. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, Hunter [School of Packaging, Michigan State University, East Lansing, Michigan (United States); Li, Yana [Mechanical Engineering College, Wuhan Polytechnic University (China); Almenar, Eva, E-mail: ealmenar@msu.edu [School of Packaging, Michigan State University, East Lansing, Michigan (United States)

    2015-03-30

    Graphical abstract: - Highlights: • Surface tension between PLA/CS blend solution and PLA film modified by MDI. • Better wettability between PLA/CS blend solution and PLA film by increasing MDI. • Increased breaking strength by increasing MDI due to the increased H-bonding. • Increased number of physical entanglements between PLA/CS coating and PLA film. • Development of a suitable bio-based multilayer film for food packaging applications. - Abstract: The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41–35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228–303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  4. CHARACTERIZING THE SOIL FOR IMPROVED NUTRIENT MANAGEMENT IN SELECTED MAIZE GROWING AREAS OF INDONESIA

    Directory of Open Access Journals (Sweden)

    Achmad I. Fauzi

    2011-04-01

    Full Text Available The demand for maize, the second most important food crop in Indonesia, is steadily increasing. Knowledge of soil properties is a key element in developing nutrient management system. The aims of this study were to characterize and classify the soils at the family level of Soil Taxonomy and linking the taxa with nutrient management systems. The study was conducted at the Site Specific Nutrient Management (SSNM for maize in Indonesia from June to October 2005. Eight soil profiles were taken from Karo (North Sumatra, Sidomulyo (Lampung, Wonogiri and Grobogan (Central Java, Wonokerto, Mojoayu, and Tuban (East Java, and Jeneponto (South Sulawesi. The soil samples were analyzed for their physical, chemical, and mineralogical characteristics. Soil profile description followed the Standard Guidelines of the Food and Agriculture Organiza-tion. Results showed that the sites for the SSNM represented a wide range of soils and climate characteristics from Entisols with 1,050 mm annual rainfall in Jeneponto to Oxisols with 2,200 mm annual rainfall in Lampung. Most soils had a fine texture class (clay and clay loam, but in places like Lampung and Wonogiri, the clay had a low activity leading to a low cation exchange capacity (CEC and low exchangeable cations, especially K. The relatively high-K status soils were found in Karo, Grobogan, and Tuban sites. Organic matter and, in consequence, total N were relatively low for all SSNM sites. Available P status ranged from low to high. The low available P in Grobogan, Wonokerto, and Mojoayu soils seemed to be related to high pH, while in Lampung it was due to low pH. Exchangeable Ca and Mg were high in Grobogan, Mojoayu, Karo, and Tuban due to the presence of weatherable minerals such as hypersthene, augite, and hornblende. In general, this study suggests that organic matter, N, and P will be needed across the sites. K addition will be necessary for Karo, Lampung and Wonogiri, while in other SSNM areas, maintenance

  5. Improving the affinity of silicon surface for biosensor application: The interaction between multiwall carbon nanotube (MWCNT) and chitosan (CS)

    Science.gov (United States)

    Vijayakumaran, Thivina; Hashim, U.; Ruslinda, A. Rahim; Arshad, M. K.; Veeradasan, P.; Nordin, N. K. S.

    2017-03-01

    Previous study show the preparation, characterization and physical properties of carbon nanotube (CNT) and chitosan (CS). Multi-Wall CNT (MWCNT) and chitosan is utilized on the silicon surface in this studies. Functionalized of Multi Wall Carbon Nanotubes (MWCNTs) were demonstrated using the nitric acid (HNO3) oxidation technique to remove impurities. In this studies, the interaction between CS-MWCNT was investigated and explained according to the UV-VIS result. The range of the wavelength obtained from the UV-Vis data is 200-700nm. The hybrid form of CS-MWCNT proves to be more promising as a surface for biosensing application.

  6. Integrated application of February Orchid (Orychophragmus violaceus) as green manure with chemical fertilizer for improving grain yield and reducing nitrogen losses in spring maize system in northern China

    Institute of Scientific and Technical Information of China (English)

    BAI Jin-shun; CAO Wei-dong; XIONG Jing; ZENG Nao-hua; GAO Song-juan; Shimizu Katsuyoshi

    2015-01-01

    The development of more efifcient management systems is crucial to achieving high grain yields with high nitrogen use efifciency (NUE). February Orchid-spring maize rotation system is a newly established planting system with the beneifts of ground cover and potential wind erosion in northern China. A ifeld experiment was conducted to evaluate the effects of integrated application of February Orchid as green manure with reduction of chemical fertilizers (INTEGRATED) on spring maize yield, N uptake, ammonium volatilization, and soil residual mineral N in northern China. Compared to farmers’ traditional fertilization (CON), integrated application of February Orchid as green manure with 30% reduction of nitrogen fertilizers (INTEGRATED) increased maize grain yield and biomass by 9.9 and 10.2%, respectively. The 0–100 cm soil residual Nmin at harvest was decreased by 58.5% and thus nitrogen use efifciency was increased signiifcantly by 26.7%. The nitrogen balance calculation further demonstrated that the INTEGRATED approach performed better than CON with lower apparent nitrogen loss (decreased by 48.9%) which evidenced by the ammonium volatilization of top-dressing fertilizer was decreased by 31.1%, the Nmin movement to the deeper soil layers was reduced, and the apparent nitrogen leaching loss nearly equal to 0 under the INTEGRATED treatment. Therefore, in northern China, integrated application of green manure and chemical fertilizers is an efifcient management approach for improving maize yields and NUE simultaneously.

  7. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    Science.gov (United States)

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications.

  8. Preparation of chitosan nanofibers from completely deacetylated chitosan powder by a downsizing process.

    Science.gov (United States)

    Aklog, Yihun Fantahun; Dutta, Ajoy Kumar; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Ifuku, Shinsuke

    2015-01-01

    Chitosan nanofibers were easily prepared from fully deacetylated chitosan dry powder using a high-pressure waterjet system. From SEM observation, after 10 cycles of treatment, most of the chitosan had been reduced to homogeneous nanofibers measuring tens of nanometers. On the other hand, further mechanical treatment did not show a significant change. Relative crystallinity of chitosan nanofibers gradually decreased as the number of passes increased since high-pressure waterjet treatment damaged the crystalline region of chitosan nanofibers. The transmittance of the chitosan nanofiber slurry increased steeply, as the number of passes increased, indicating that the chitosan fibers were disintegrated effectively. Viscosity of chitosan nanofiber slurry also showed that the chitosan disintegrated well into nanofibers up to 10 passes. Above 10 passes, disintegration efficiency was saturated. The molecular weights of the nanofibers steeply decreased due to the depolymerization of chitosan by mechanical disintegration. The Young's modulus and tensile strength of chitosan nanofiber sheets were improved as the number of treatments increased, but further treatments deteriorated the tensile strength.

  9. Improvement of metal adsorption onto chitosan/Sargassum sp. composite sorbent by an innovative ion-imprint technology.

    Science.gov (United States)

    Liu, Huijuan; Yang, Fan; Zheng, Yuming; Kang, Jin; Qu, Jiuhui; Chen, J Paul

    2011-01-01

    Technology for immobilization of biomass has attracted a great interest due to the high sorption capacity of biomass for sequestration of toxic metals from industrial effluents. However, the currently practiced immobilization methods normally reduce the metal sorption capacities. In this study, an innovative ion-imprint technology was developed to overcome the drawback. Copper ion was first imprinted onto the functional groups of chitosan that formed a pellet-typed sorbent through the granulation with Sargassum sp.; the imprinted copper ion was chemically detached from the sorbent, leading to the formation of a novel copper ion-imprinted chitosan/Sargassum sp. (CICS) composite adsorbent. The copper sorption on CICS was found to be highly pH-dependent and the maximum uptake capacity was achieved at pH 4.7-5.5. The adsorption isotherm study showed the maximum sorption capacity of CICS of 1.08 mmol/g, much higher than the non-imprinted chitosan/Sargassum sp. sorbent (NICS) (0.49 mmol/g). The used sorbent was reusable after being regenerated through desorption. The FTIR and XPS studies revealed that the greater sorption of heavy metal was attributed to the large number of primary amine groups available on the surfaces of the ion-imprinted chitosan and the abundant carboxyl groups on Sargassum sp. Finally, an intraparticle surface diffusion controlled model well described the sorption history of the sorbents.

  10. Chitosan-based dressings loaded with neurotensin--an efficient strategy to improve early diabetic wound healing.

    Science.gov (United States)

    Moura, Liane I F; Dias, Ana M A; Leal, Ermelindo C; Carvalho, Lina; de Sousa, Hermínio C; Carvalho, Eugénia

    2014-02-01

    One important complication of diabetes mellitus is chronic, non-healing diabetic foot ulcers (DFUs). This study aims to develop and use dressings based on chitosan derivatives for the sustained delivery of neurotensin (NT), a neuropeptide that acts as an inflammatory modulator in wound healing. Three different derivatives, namely N-carboxymethyl chitosan, 5-methyl pyrrolidinone chitosan (MPC) and N-succinyl chitosan, are presented as potential biomaterials for wound healing applications. Our results show that MPC has the best fluid handling capacity and delivery profile, also being non-toxic to Raw 264.7 and HaCaT cells. NT-loaded and non-loaded MPC dressings were applied to control/diabetic wounds to evaluate their in vitro/in vivo performance. The results show that the former induced more rapid healing (50% wound area reduction) in the early phases of wound healing in diabetic mice. A NT-loaded MPC foam also reduced expression of the inflammatory cytokine TNF-α (P<0.001) and decreased the amount of inflammatory infiltrate on day 3. On day 10 MMP-9 was reduced in diabetic skin (P<0.001), significantly increasing fibroblast migration and collagen (COL1A1, COL1A2 and COL3A1) expression and deposition. These results suggest that MPC-based dressings may work as an effective support for sustained NT release to reduce DFUs.

  11. Chemical treatment and chitosan coating of yeast cells to improve the encapsulation and controlled release of bovine serum albumin.

    Science.gov (United States)

    Shi, Guorong; Liu, Yating; He, Zijun; Zhou, Jihen

    2016-08-10

    We investigate the encapsulation of bovine serum albumin (BSA) in chemical-treated and chitosan-coated yeast cells, Saccharomyces cerevisiae (S. cerevisiae), for the controlled release of BSA. The chemical treatment can sufficiently enlarge the small-sized cell-wall cavities and/or break the integrity for the entrance of BSA to the interior of yeast cells, and the additional chitosan coating can well prevent the rapid release of encapsulated BSA from the yeast-derived microcapsules. The sodium hydroxide pretreated S. cerevisiae gives a maximum encapsulation yield of (10.1 ± 0.2)% for BSA. An additional coating of S. cerevisiae with chitosan can reduce the initial burst release of BSA and extend the release period from 24 h in the chitosan-free case to 48 h in phosphate buffer at pH 7.4. The prepared microcapsules can well keep the shapes and sizes of yeast cells and thus show uniform sizes of 3.85 ± 0.81 μm. The encapsulated BSA well retains its pristine ultraviolet spectroscopic and chromatographic behaviors. The present microencapsulation protocol has the advantages of convenient and mild operation, high encapsulation efficiency, and organic solvent-free nature, which is of reference value for establishing high-performance controllable biomacromolecule-delivery systems.

  12. Exploration of agro-ecological options for improving maize-based farming systems in Costa Chica, Guerrero, Mexico

    NARCIS (Netherlands)

    Flores Sanchez, D.

    2013-01-01

    Keywords: farm diagnosis, farming systems, soil degradation, intercropping, maize, roselle, legumes, nutrient management, vermicompost, crop residues, decomposition, explorations.   In the Costa Chica, a region of Southwest Mexico, farming systems are organized in smallholder

  13. An oral chitosan DNA vaccine against nodavirus improves transcription of cell-mediated cytotoxicity and interferon genes in the European sea bass juveniles gut and survival upon infection.

    Science.gov (United States)

    Valero, Yulema; Awad, Elham; Buonocore, Francesco; Arizcun, Marta; Esteban, M Ángeles; Meseguer, José; Chaves-Pozo, Elena; Cuesta, Alberto

    2016-12-01

    Vaccines for fish need to be improved for the aquaculture sector, with DNA vaccines and the oral administration route providing the most promising improvements. In this study, we have created an oral chitosan-encapsulated DNA vaccine (CP-pNNV) for the nodavirus (NNV) in order to protect the very susceptible European sea bass (Dicentrarchus labrax). Our data show that the oral CP-pNNV vaccine failed to induce serum circulating or neutralizing specific antibodies (immunoglobulin M) or to up-regulate their gene expression in the posterior gut. However, the vaccine up-regulated the expression of genes related to the cell-mediated cytotoxicity (CMC; tcrb and cd8a) and the interferon pathway (IFN; ifn, mx and ifng). In addition, 3 months after vaccination, challenged fish showed a retarded onset of fish death and lower cumulative mortality with a relative survival of 45%. Thus, we created a chitosan-encapsulated DNA vaccine against NNV that is partly protective to European sea bass juveniles and up-regulates the transcription of genes related to CMC and IFN. However, further studies are needed to improve the anti-NNV vaccine and to understand its mechanisms.

  14. The role of maize root size in phosphorus uptake and productivity of maize/faba bean and maize/wheat intercropping systems.

    Science.gov (United States)

    Zhang, Yikai; Chen, Fanjun; Li, Long; Chen, Yanhua; Liu, Bingran; Zhou, Yuling; Yuan, Lixing; Zhang, Fusuo; Mi, Guohua

    2012-11-01

    Interspecific root/rhizosphere interactions affect phosphorus (P) uptake and the productivity of maize/faba bean and maize/wheat intercropping systems. The aim of these experiments was to determine whether manipulation of maize root growth could improve the productivity of the two intercropping systems. Two near isogenic maize hybrids (the larger-rooted T149 and smaller-rooted T222) were intercropped with faba bean and wheat, under conditions of high- and low-P availability. The larger-rooted T149 showed greater competitive ability than the smaller-rooted T222 in both maize/faba bean and maize/wheat intercropping systems. The higher competitive ability of T149 improved the productivity of the maize/faba bean intercropping system in P-sufficient conditions. In maize/wheat intercropping systems, root growth, shoot biomass, and P uptake of maize were inhibited by wheat, regardless of the P-supply. Compared with T222, the larger-rooted T149 suffered less in the intercropping systems. The total biomass of the maize/wheat intercropping system was higher for wheat/T149 than for wheat/T222 under low-P conditions. These data suggested that genetic improvement of maize root size could enhance maize growth and its ability to compete for P resources in maize/faba bean and maize/wheat intercropping systems. In addition, depending on the P availability, larger maize roots could increase the productivity of intercropping systems.

  15. Facile and scalable fabrication engineering of fullerenol nanoparticles by improved alkaline-oxidation approach and its antioxidant potential in maize

    Science.gov (United States)

    Liu, Fu-yang; Xiong, Feng-xia; Fan, Yi-kang; Li, Juan; Wang, He-zhong; Xing, Geng-mei; Yan, Feng-ming; Tai, Fu-ju; He, Rui

    2016-11-01

    A feasible in operation, labor-saving and low-cost one-step technology to fabricate fullerenol nanoparticles (FNPs) up to 10 g in laboratory was developed by improved alkaline-oxidation approach using moderately concentrated sodium hydroxide solution as the hydroxylation agent and o-dichlorobenzene as the solvent. This strategy paves the avenue for industrial-scale bulk production of FNPs. The resulted product, [C60(OH)22·8H2O]n, were characterized by various measurements including matrix-assisted laser desorption ionization time-of-flight mass spectrometry, high-resolution 1H nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, UV-Visible spectrophotometer, thermogravimetric analysis, differential scanning calorimetry, dynamic light scattering analysis, scanning electron microscopy, and electron spin resonance spectrometer. Radical scavenging assay in vitro confirmed the high efficiency of water-soluble [C60(OH)22·8H2O]n as a novel radical scavenger. Furthermore, [C60(OH)22·8H2O]n as an excellent candidate has the potential to serve as the plant defense stimulation agent in maize.

  16. Nanoindentation of Chitosan Doped with Silver Nanoparticles

    Science.gov (United States)

    Palumbo, Matthew; Teklu, Alem; Kuthirummal, Narayanan; Levi-Polyachenko, Nicole; Department of Physics; Astronomy, College of Charleston Collaboration; Department of Plastic; Reconstructive Surgery, Wake Forest University Health Sciences Collaboration

    Imaging and spectroscopic analysis via nanoindentation was performed with the Nanosurf EasyScan2 AFM on the pure and silver doped chitosan samples allowing for a more localized determination of their stiffness, hardness, and reduced Young's modulus. The pure chitosan sample was tested to have a stiffness of 0.367 N/m, a hardness of 1.12 GPa, and a reduced Young's modulus of 30.5 MPa. The film with 5mg Ag nanoparticle per gram of chitosan was tested on the boundaries between the chitosan and Ag nanoparticles to show an increase in stiffness of about 4.6% at 0.384 N/m, an increase in hardness of about 5.4% at 1.18 GPa, and an increase in the reduced Young's modulus of about 5.0% at 3.2 MPa in comparison to the pure chitosan sample. On the other hand, upon increasing the doping to 10mg Ag nanoparticle per gram of chitosan showed a decrease in stiffness of about 6.3% at 0.344 N/m, a decrease in hardness of about 27.0% at 0.820 GPa, and a decrease in the reduced Young's modulus of about 6.0% at 28.7 MPa in comparison to the pure chitosan sample. Obviously, films doped with 5mg Ag nanoparicle per gram of chitosan provided the composites with improved mechanical strength compared to chitosan alone.

  17. Infiltration and planting pits for improved water management and maize yield in semi-arid Zimbabwe

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.; Nyagumbo, I.

    2014-01-01

    Realising that rainwater harvesting (RWH) improves crop productivity, smallholder farmers in semi-arid Zimbabwe modified contour ridges traditionally used for rainwater management by digging infiltration pits inside contour ridge channels in order to retain more water in crop fields. However, scient

  18. Ensuring Improved Livelihood Opportunities for Resource-Poor Maize Farmers through the Dissemination of Striga Control Methods in Kwara State, Nigeria

    Directory of Open Access Journals (Sweden)

    OLORUNFEMI, O.D

    2014-06-01

    Full Text Available This paper examines the sources used by resource poor maize farmers in search of agricultural information on Striga control methods in Kwara State, Nigeria. A well structured interview schedule was used to elicit information using random sampling technique from one hundred and sixty (160 maize farmers in Edu and Patigi Local Government Areas which are highly endemic to Striga infestation in the State. Four sources of information were found effective in disseminating and diffusing Striga control methods in the area which include neighbours and friends, government agencies (ADP, agricultural extension agents and farmers groups. Logistic regression model of determinants of poverty revealed that characteristics of households that were more likely to be impoverished include small household size; low farm income, few years of farming experience and those whom Striga have been on their farms for long thereby having high yield loss to Striga. The study recommends an urgent need for extension agencies to intensify the use of the effective sources of information for disseminating Striga control methods to the farmers and it highlighted policies to improve the livelihoods of the resource-poor maize farmers in the Striga affected areas of Kwara State, Nigeria.

  19. Fabrication and characterization of nuclear localization signal-conjugated glycol chitosan micelles for improving the nuclear delivery of doxorubicin

    Directory of Open Access Journals (Sweden)

    Zhao J

    2012-09-01

    Full Text Available Jingmou Yu,1 Xin Xie,1 Meirong Zheng,1 Ling Yu,2 Lei Zhang,1 Jianguo Zhao,1 Dengzhao Jiang,1 Xiangxin Che11Key Laboratory of Systems Biology Medicine of Jiangxi Province, College of Basic Medical Science, Jiujiang University, Jiujiang, 2Division of Nursing, 2nd Affiliated Hospital, Yichun University, Yichun, People's Republic of ChinaBackground: Supramolecular micelles as drug-delivery vehicles are generally unable to enter the nucleus of nondividing cells. In the work reported here, nuclear localization signal (NLS-modified polymeric micelles were studied with the aim of improving nuclear drug delivery.Methods: In this research, cholesterol-modified glycol chitosan (CHGC was synthesized. NLS-conjugated CHGC (NCHGC was synthesized and characterized using proton nuclear magnetic resonance spectroscopy, dynamic light scattering, and fluorescence spectroscopy. Doxorubicin (DOX, an anticancer drug with an intracellular site of action in the nucleus, was chosen as a model drug. DOX-loaded micelles were prepared by an emulsion/solvent evaporation method. The cellular uptake of different DOX formulations was analyzed by flow cytometry and confocal laser scanning microscopy. The cytotoxicity of blank micelles, free DOX, and DOX-loaded micelles in vitro was investigated by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay in HeLa and HepG2 cells.Results: The degree of substitution was 5.9 cholesterol and 3.8 NLS groups per 100 sugar residues of the NCHGC conjugate. The critical aggregation concentration of the NCHGC micelles in aqueous solution was 0.0209 mg/mL. The DOX-loaded NCHGC (DNCHGC micelles were observed as being almost spherical in shape under transmission electron microscopy, and the size was determined as 248 nm by dynamic light scattering. The DOX-loading content of the DNCHGC micelles was 10.1%. The DOX-loaded micelles showed slow drug-release behavior within 72 hours in vitro. The DNCHGC micelles exhibited greater

  20. Curcumin-carboxymethyl chitosan (CNC) conjugate and CNC/LHR mixed polymeric micelles as new approaches to improve the oral absorption of P-gp substrate drugs.

    Science.gov (United States)

    Ni, Jiang; Tian, Fengchun; Dahmani, Fatima Zohra; Yang, Hui; Yue, Deren; He, Shuwang; Zhou, Jianping; Yao, Jing

    2016-11-01

    The low oral bioavailability of numerous drugs has been mostly attributed to the significant effect of P-gp-mediated efflux on intestinal drug transport. Herein, we developed mixed polymeric micelles (MPMs) comprised of curcumin-carboxymethyl chitosan (CNC) conjugate, as a potential inhibitor of P-gp-mediated efflux and gastrointestinal absorption enhancer, and low-molecular-weight heparin-all-trans-retinoid acid (LHR) conjugate, as loading material, with the aim to improve the oral absorption of P-gp substrate drugs. CNC conjugate was synthesized by chemical bonding of curcumin (Cur) and carboxymethyl chitosan (CMCS) taking advantage of the inhibition of intestinal P-gp-mediated secretion by Cur and the intestinal absorption enhancement by CMCS. The chemical structure of CNC conjugate was characterized by (1)H NMR with a degree of substitution of Cur of 4.52-10.20%. More importantly, CNC conjugate markedly improved the stability of Cur in physiological pH. Cyclosporine A-loaded CNC/LHR MPMs (CsA-CNC/LHR MPMs) were prepared by dialysis method, with high drug loading 25.45% and nanoscaled particle size (∼200 nm). In situ single-pass perfusion studies in rats showed that both CsA + CNC mixture and CsA-CNC/LHR MPMs achieved significantly higher Ka and Peff than CsA suspension in the duodenum and jejunum segments (p absorption enhancer, while CNC/LHR MPMs had the potential to improve the oral absorption of P-gp substrate drugs.

  1. Melhoramento genético do cultivar de milho IAC-1 Genetic improvement of the maize cultivars IAC-1

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    Luiz Torres de Miranda

    1978-01-01

    Full Text Available São relatados os resultados obtidos no melhoramento do cultivar de milho IAC-1 pela introdução de linhagens prolíficas nesta população, que já vinha sendo melhorada há oito ciclos pelo método de seleção entre e dentro de famílias de meios irmãos. Para produção de grãos foi observado um progresso genético médio de 3,3% por ciclo, comparado com um progresso genético esperado de 7,2% por ciclo. Para índice-de-espigas foi observado um progresso genético de 8,9% e um progresso genético espe-rado de 1,9% por ciclo. Com a introdução de fatores de prolificidade, o índice-de-espigas aumentou consideravelmente superando inclusive o do híbrido duplo comercial utilizado como controle. Houve pequeno aumento da porcentagem de plantas acamadas e quebra-das, com o decorrer dos ciclos de seleção. Computando-se os ganhos obtidos inicialmente neste cultivar, houve em 10 ciclos de seleção um progresso acumulado de 28% para produção de grãos e de 10% para índice-de-espigas, sendo este último obtido quase exclusivamente após a introdução das linha-gens prolíficas.There are presented results of the improvement of the maize (Zea mays, L. cultivars IAC-1, after the introduction of prolificacy in a population formerly improved for eight cycles by the modified ear-to-row procedure. It was obtained an average progress of 3.3% per cycle in grain yield, against an expected genetic progress of 7.2% per cycle. For the ear index a genetic progress of 8.9% per cycle was observed and an expected genetic progress of 1.9% per cycle was estimated. With the introduction of prolificacy factors, ear index increased considerably outyielding the commercial double hybrid control Lodging changed 'very little with the cycles of selection. The IAC-1 cultivars showed an accumulated progress of 28% for grain yield and 10% for ear index. The gain in ear index is mainly due to the prolific inbred lines introduced in the synthetic.

  2. Study on the Effect of Silanization and Improvement in the Tensile Behavior of Graphene-Chitosan-Composite

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    Dae Sung Kim

    2015-03-01

    Full Text Available In the present study, silane-functionalized graphene (f-graphene-reinforced chitosan nanocomposite films exhibiting enhanced mechanical properties have been prepared by the solution casting method. These nanocomposite films were characterized by X-ray diffraction, Raman spectroscopy and thermogravimetric analysis. In order to investigate the effect of silane functionalization, tensile tests were performed on original, oxidized and silane-functionalized graphene-reinforced chitosan nanocomposite films. Tensile results show that silane functionalization groups offer a substantial increase in the interfacial adhesion between filler and host matrix. This result is also confirmed by the surface morphology of the fracture surface in scanning electron microscope analysis. Qualitative analysis using Raman and Fourier transform infrared spectroscopy revealed the existence of Si–O–Si and Si–O–C bonds in the silanized composite. Thermal analysis of the samples shows that the material is stable up till 250 °C and maintains its thermal stability all throughout the process until it starts degrading after 510 °C. Atomic force microscopy reveals that the material is well exfoliated after the oxidation of graphene and also displays the existence of 3–6 layers of exfoliated graphene sheets. X-ray photoelectron spectroscopy studies also reveal the existence of silicon in the single state and quantify the sample to be approximately around 4% (±0.5% of the total atomic weight.

  3. Chitosan-based adsorption and freeze deproteinization: Improved extraction and purification of synthetic colorants from protein-rich food samples.

    Science.gov (United States)

    Kong, Cong; Fodjo, Essy Kouadio; Li, Dan; Cai, Youqiong; Huang, Dongmei; Wang, Yuan; Shen, Xiaosheng

    2015-12-01

    A freeze method for deproteinization coupling with the chitosan purification process was developed for the determination of 8 synthetic food colorants in protein-rich samples. The solvents for extraction and different methods for deproteinization were examined and selected. Chitosan was employed for the purification after deproteinization, and further compared with the traditional polyamine purification method. Determination of the purified extract was conducted through the separation using high performance liquid chromatography and detection by multi-wavelength mode. Under the optimum conditions, the method showed good linearity between 0.6 and 10mg/kg, for the 8 synthetic colorants, and the limit of detection was between 0.1 and 0.4 mg/kg as was defined when the ratio of signal to noise was three. The recoveries of the spiked samples were found to be between 83% and 91%. The intra-day precision and inter-day precision was estimated to be 3-10% and 6-12%, respectively. The developed method could be applied to deproteinization and clean-up for pretreatment of protein-rich samples.

  4. Nanoparticle mediated P-glycoprotein silencing for improved drug delivery across the blood-brain barrier: a siRNA-chitosan approach.

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    Jostein Malmo

    Full Text Available The blood-brain barrier (BBB, composed of tightly organized endothelial cells, limits the availability of drugs to therapeutic targets in the central nervous system. The barrier is maintained by membrane bound efflux pumps efficiently transporting specific xenobiotics back into the blood. The efflux pump P-glycoprotein (P-gp, expressed at high levels in brain endothelial cells, has several drug substrates. Consequently, siRNA mediated silencing of the P-gp gene is one possible strategy how to improve the delivery of drugs to the brain. Herein, we investigated the potential of siRNA-chitosan nanoparticles in silencing P-gp in a BBB model. We show that the transfection of rat brain endothelial cells mediated effective knockdown of P-gp with subsequent decrease in P-gp substrate efflux. This resulted in increased cellular delivery and efficacy of the model drug doxorubicin.

  5. Modification of solid lipid nanoparticles loaded with nebivolol hydrochloride for improvement of oral bioavailability in treatment of hypertension: polyethylene glycol versus chitosan oligosaccharide lactate.

    Science.gov (United States)

    Üstündağ-Okur, Neslihan; Yurdasiper, Aysu; Gündoğdu, Evren; Gökçe, Evren Homan

    2016-02-01

    Nebivolol (NB)-loaded solid lipid nanoparticles (SLNs) were prepared and modified with chitosan oligosaccharide lactate (COL) and polyethylene glycol (PEG) stearate for improvement of its oral bioavailability. Compritol, poloxamer and lecithin were used for the preparation of SLNs by homogenisation method. After in vitro characterisation effect of lipase, pepsin, or pancreatin on degradation and release rate were investigated. Cytotoxicity and permeation were studied on Caco-2 cells. As COL concentration increased in SLNs, size and zeta potential increased. PEG concentration was reversely proportional to particle size with no change in zeta potential. Encapsulation efficiencies (EEs) were determined as 84-98%. DSC confirmed solubilisation of NB in lipid matrix. A sustained release with no burst effect was determined. The presence of enzymes affected the release. SLNs did not reveal cytotoxicity and highest permeability was obtained with PEG modification. PEG-modified SLNs could be offered as a promising strategy for oral delivery of NB.

  6. Suppression of Zn stress on barley by irradiated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, N.; Mitomo, H. [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan); Ha, P.T.L. [Nuclear Research Institute, Dalat (Viet Nam); Watanabe, S.; Ito, T.; Takeshita, H.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 10{sup 5} to ca. 6 x 10{sup 3} by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of {sup 62}Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  7. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L. under Water Deficit Conditions

    Directory of Open Access Journals (Sweden)

    Fahim Nawaz

    2016-09-01

    Full Text Available Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium (Se supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L. under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity and water stress (60% field capacity conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing and was repeated after one week, whereas water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41% and enhanced relative water contents (30%, total chlorophyll (53%, carotenoid contents (60%, accumulation of total free amino acids (40% and activities of superoxide dismutase (53%, catalase (30%, peroxidase (27% and ascorbate peroxidase (27% with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15% and increased crude protein (47%, fibre (10%, nitrogen free extract (10% and Se content (36% but did not affect crude ash content in water stressed maize plants. We propose

  8. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions

    Science.gov (United States)

    Nawaz, Fahim; Naeem, Muhammad; Ashraf, Muhammad Y.; Tahir, Muhammad N.; Zulfiqar, Bilal; Salahuddin, Muhammad; Shabbir, Rana N.; Aslam, Muhammad

    2016-01-01

    Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se

  9. Chitosan in Mucoadhesive Drug Delivery: Focus on Local Vaginal Therapy

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    Toril Andersen

    2015-01-01

    Full Text Available Mucoadhesive drug therapy destined for localized drug treatment is gaining increasing importance in today’s drug development. Chitosan, due to its known biodegradability, bioadhesiveness and excellent safety profile offers means to improve mucosal drug therapy. We have used chitosan as mucoadhesive polymer to develop liposomes able to ensure prolonged residence time at vaginal site. Two types of mucoadhesive liposomes, namely the chitosan-coated liposomes and chitosan-containing liposomes, where chitosan is both embedded and surface-available, were made of soy phosphatidylcholine with entrapped fluorescence markers of two molecular weights, FITC-dextran 4000 and 20,000, respectively. Both liposomal types were characterized for their size distribution, zeta potential, entrapment efficiency and the in vitro release profile, and compared to plain liposomes. The proof of chitosan being both surface-available as well as embedded into the liposomes in the chitosan-containing liposomes was found. The capability of the surface-available chitosan to interact with the model porcine mucin was confirmed for both chitosan-containing and chitosan-coated liposomes implying potential mucoadhesive behavior. Chitosan-containing liposomes were shown to be superior in respect to the simplicity of preparation, FITC-dextran load, mucoadhesiveness and in vitro release and are expected to ensure prolonged residence time on the vaginal mucosa providing localized sustained release of entrapped model substances.

  10. Improvement of intestinal absorption of forsythoside A and chlorogenic acid by different carboxymethyl chitosan and chito-oligosaccharide, application to Flos Lonicerae-Fructus Forsythiae herb couple preparations.

    Directory of Open Access Journals (Sweden)

    Wei Zhou

    Full Text Available The current study aims to investigate the effect of chitosan derivatives on the intestinal absorption and bioavailabilities of forsythoside A (FTA and Chlorogenic acid (CHA, the major active components in Flos Lonicerae-Fructus Forsythiae herb couple. Biopharmaceutics and pharmacokinetics properties of the two compounds have been characterized in vitro, in situ as well as in rats. Based on the identified biopharmaceutics characteristics of the two compounds, the effect of chitosan derivatives as an absorption enhancer on the intestinal absorption and pharmacokinetics of FTA and CHA in pure compound form as well as extract form were investigated in vitro, in situ and in vivo. Both FTA and CHA demonstrated very limited intestinal permeabilities, leading to oral bioavailabilities being only 0.50% and 0.13% in rats, respectively. Results from both in vitro, in situ as well as in vivo studies consistently indicated that Chito-oligosaccharide (COS at dosage of 25 mg/kg could enhance intestinal permeabilities significantly as well as the in vivo bioavailabilities of both FTA and CHA than CMCs in Flos Lonicerae-Fructus Forsythiae herb couple preparations, and was safe for gastrointestine from morphological observation. Besides, treatment with Flos Lonicerae-Fructus Forsythiae herb couple preparations with COS at the dosage of 25 mg/kg prevented MDCK damage after influenza virus propagation, which was significantly better than control. The current findings not only identified the usefulness of COS for the improved delivery of Flos Lonicerae-Fructus Forsythiae preparations but also demonstrated the importance of biopharmaceutical characterization in the dosage form development of traditional Chinese medicine.

  11. Anaerobic lactic acid degradation during ensilage of whole crop maize inoculated with lactobacillus buchneri inhibits yeast growth and improves aerobic stability

    Science.gov (United States)

    Driehuis; Elferink; Spoelstra

    1999-10-01

    Aerobic deterioration of silages is initiated by (facultative) aerobic micro-organisms, usually yeasts, that oxidize the preserving organic acids. In this study, a Lactobacillus buchneri strain isolated from maize silage was evaluated for its potential as a bacterial inoculant that enhances aerobic stability of silages. In four experiments, chopped whole crop maize (30-43% dry matter (DM)) was inoculated with Lact. buchneri and ensiled in laboratory silos. Uninoculated silages served as controls. Analysis of silages treated with Lact. buchneri at levels of 103-106 cfu g-1 after about 3 months of anaerobic storage showedthat acetic acid and 1-propanol contents increased with inoculum levels above 104 cfu g-1,whereas lactic acid decreased. Propionic acid, silage pH and DM loss increased withinoculum levels above 105 cfu g-1. Time course experiments with maize inoculated with Lact. buchneri at 4 x 104-2 x 105 cfu g-1 showed that up to 7-14 d after ensiling, Lact. buchneri had no effect on silage characteristics. Thereafter, the lactic acid content of the inoculated silages declined and, simultaneously, acetic acid and, to a lesser extent, propionic acid and 1-propanol, accumulated. Inoculation reduced survival of yeasts during the anaerobic storage phase and inhibited yeast growth when the silage was exposed to O2, resulting in a substantial improvement in aerobic stability. The results indicate that the use of Lact. buchneri as a silage inoculant can enhance aerobic stability by inhibition of yeasts. The ability of the organism to ferment lactic acid to acetic acid appears to be an important underlying principle of this effect.

  12. In-Season Root-Zone Nitrogen Management Strategies for Improving Nitrogen Use Efficiency in High-Yielding Maize Production in China

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-Feng; CHEN Xin-Ping; ZHANG Fu-Suo; CAO Ming-Hui; CUI Zhen-Ling; BAI Jin-Shun; YUE Shan-Chao; CHEN Su-Yi; T.M(U)LLER

    2012-01-01

    Many recently developed N management strategies have been extremely successful in improving N use efficiency.However,attempts to further increase grain yields have had limited success.Field experiments were conducted in 2007 and 2008 at four sites to evaluate the effect of an in-season root-zone N management strategy on maize (Zea mays L.).According to the in-season root-zone N management,the optimal N rate (ONR) was determined by subtracting measured soil mineral N (NH4+-N and NO3--N) in the root zone from N target values.Other treatments included a control without N fertilization,70% of ONR,130% of ONR,and recommended N rate (RNR) by agronomists in China that have been shown to approach maize yield potentials.Although apparent N recovery for the ONR treatment was significantly higher than that under RNR in 2007,grain yield declined from 13.3 to 11.0 Mg ha-1 because of an underestimation of N uptake.In 2008,N target values were adjusted to match crop uptake,and N fertilization rates were reduced from 450 kg N ha- 1 for RNR to 225 to 265 kg N ha-1 for ONR.High maize yields were maintained at 12.6 to 13.5 Mg ha-1,which were twice the yield from typical farmers'practice.As a result,apparent N recovery increased from 29% to 66%,and estimated N losses decreased significantly for the ONR treatment compared to the RNR treatment.In conclusion,the in-season root-zone N management approach was able to achieve high yields,high NUE and low N losses.

  13. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan.

    Science.gov (United States)

    Zhang, Luzhong; Dou, Sufeng; Li, Yan; Yuan, Ying; Ji, Yawei; Wang, Yaling; Yang, Yumin

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields.

  14. Romanian maize

    DEFF Research Database (Denmark)

    Sauer, Johannes; Balint, Borbala

    This research aims at shedding empirical light on the relative efficiency of small-scale maize producers in Romania. Farmers in transition countries still face heavily distorted price systems resulting from imperfect market conditions and socioeconomic and institutional constraints. To capture...

  15. Environmental applications of chitosan and its derivatives.

    Science.gov (United States)

    Yong, Soon Kong; Shrivastava, Manoj; Srivastava, Prashant; Kunhikrishnan, Anitha; Bolan, Nanthi

    2015-01-01

    Chitosan originates from the seafood processing industry and is one of the most abundant of bio-waste materials. Chitosan is a by-product of the alkaline deacetylation process of chitin. Chemically, chitosan is a polysaccharide that is soluble in acidic solution and precipitates at higher pHs. It has great potential for certain environmental applications, such as remediation of organic and inorganic contaminants, including toxic metals and dyes in soil, sediment and water, and development of contaminant sensors. Traditionally, seafood waste has been the primary source of chitin. More recently, alternative sources have emerged such as fungal mycelium, mushroom and krill wastes, and these new sources of chitin and chitosan may overcome seasonal supply limitations that have existed. The production of chitosan from the above-mentioned waste streams not only reduces waste volume, but alleviates pressure on landfills to which the waste would otherwise go. Chitosan production involves four major steps, viz., deproteination, demineralization, bleaching and deacetylation. These four processes require excessive usage of strong alkali at different stages, and drives chitosan's production cost up, potentially making the application of high-grade chitosan for commercial remediation untenable. Alternate chitosan processing techniques, such as microbial or enzymatic processes, may become more cost-effective due to lower energy consumption and waste generation. Chitosan has proved to be versatile for so many environmental applications, because it possesses certain key functional groups, including - OH and -NH2 . However, the efficacy of chitosan is diminished at low pH because of its increased solubility and instability. These deficiencies can be overcome by modifying chitosan's structure via crosslinking. Such modification not only enhances the structural stability of chitosan under low pH conditions, but also improves its physicochemical characteristics, such as porosity

  16. Biopolymer chitosan: Properties, interactions and its use in the treatment of textiles

    Directory of Open Access Journals (Sweden)

    Jocić Dragan

    2004-01-01

    Full Text Available The biopolymer chitosan is obtained by the deacetylation of chitin, the second most abundant polysaccharide in nature, after cellulose. It is becoming an increasingly important biopolymer because it offers unique physico-chemical and biological properties. Due to its solubility, chitosan allows processing from aqueous solutions. This review provides information on important chitosan properties, as well as on some interactions that are of special interest for chitosan application. It summarizes some of the most important developments in the use of chitosan in the treatment of textile materials. Special emphasis is given to improved dyeing properties of the textile material treated with chitosan.

  17. Biotechnology in maize breeding

    Directory of Open Access Journals (Sweden)

    Mladenović-Drinić Snežana

    2004-01-01

    Full Text Available Maize is one of the most important economic crops and the best studied and most tractable genetic system among monocots. The development of biotechnology has led to a great increase in our knowledge of maize genetics and understanding of the structure and behaviour of maize genomes. Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants with preferred characteristics by "reading" at the molecular level, saving precious time and resources. DNA markers have provided valuable tools in various analyses ranging from phylogenetic analysis to the positional cloning of genes. Application of molecular markers for genetic studies of maize include: assessment of genetic variability and characterization of germ plasm, identification and fingerprinting of genotypes, estimation of genetic distance, detection of monogamic and quantitative trait loci, marker assisted selection, identification of sequence of useful candidate genes, etc. The development of high-density molecular maps which has been facilitated by PCR-based markers, have made the mapping and tagging of almost any trait possible and serve as bases for marker assisted selection. Sequencing of maize genomes would help to elucidate gene function, gene regulation and their expression. Modern biotechnology also includes an array of tools for introducing or deieting a particular gene or genes to produce plants with novel traits. Development of informatics and biotechnology are resulted in bioinformatic as well as in expansion of microarrey technique. Modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity.

  18. Bioavailability enhancement of glucosamine hydrochloride by chitosan.

    Science.gov (United States)

    Qian, Shuai; Zhang, Qizhi; Wang, Yanfeng; Lee, Benjamin; Betageri, Guru V; Chow, Moses S S; Huang, Min; Zuo, Zhong

    2013-10-15

    Glucosamine, as a dietary supplement for management of osteoarthritis, has a low and erratic oral bioavailability due to its transport-mediated absorption and presystemic loss in liver and GI tract. The present study described an effective approach to improve glucosamine intestinal absorption and hence its bioavailability using chitosan. Effects of chitosan on intestinal permeability and pharmacokinetics of glucosamine were evaluated in Caco-2 cell monolayer and rats, respectively. In addition, randomized crossover pharmacokinetic studies in beagle dogs were performed to evaluate the oral bioavailabilities of the developed glucosamine oral formulations containing chitosan (QD-Glu solution and QD-Glu tablet) in comparison to its commercial products. Caco-2 permeability studies demonstrated that chitosan could enhance the absorptive transport of glucosamine by 1.9-4.0-fold via the reversible opening of the cell tight junction. After oral administration of glucosamine solutions containing chitosan in rats, it was found that 0.5% (w/v) chitosan exhibited the highest enhancement in Cmax (2.8-fold) and AUC0-∞ (2.5-fold) of glucosamine. Further pharmacokinetic studies in beagle dogs demonstrated that QD-Glu solution and QD-Glu tablet showed much higher relative bioavailabilities of 313% and 186%, when comparing with Wellesse™ solution and Voltaflex™ tablet, respectively. In conclusion, chitosan could serve as a promising oral absorption enhancer for glucosamine.

  19. Application of bokashi and sunn hemp (Crotalaria juncea L. to improve inorganic fertilizer efficiency on maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    A.I. Yuliana

    2015-10-01

    Full Text Available A field experiment was conducted lo learn about the effect of Bokashi and Sunn hemp (Crotalaria juncea L. on maize production and inorganic fertilizer use efficiency on maize. The experiment was conducted in Jatikerto, Malang; at the altitude of 303 m above sea level, in Alfisol soil type, the average daily temperature ranges 21-33oC, from June to October 2013. The experiment was conducted as factorial, designed in a randomized block design (RBD. The first factor was dose of inorganic fertilizer (100% ; 75% and 50% of recommendation dose. The second factor was the organic fertilizer (Without organic fertilizer20 t Bokashi/ ha, 20 t Sunn hemp/ha, 10 t Bokashi/ha + 10 t Sunn hemp/ha. The results showed that application of 20 t Bokashi/ha, 20 t Sunn hemp/ha, and combination of 10 t Bokashi/ha + 10 t Sunn hemp/ha, along with the application of inorganic fertilizer by dose of 100% increased the yields of maize for about 41.8%; 47.6% and 54.7% (10.73 t/ha; 11.17 t/ha, and 11.71 t/ha, respectively. The yield and nutrient use efficiency in the treatment dose of 100% inorganic fertilizer did not have any significant difference from the application of 20 t Bokashi /ha, 20 t Sunn hemp/ha, and 10 t Bokashi/ha + 10 t Sunn hemp/ha along with doses of inorganic fertilization 75% and 50%. Therefore, the organic fertilizer of 20 t Bokashi/ ha, 20 t Sunn hemp/ha, and combination of 10 t Bokashi/ha + 10 t Sunn hemp/ha could reduce the need of inorganic fertilizer for about 50%.

  20. Contribution to the improvement of a porridge made with fermented maize: effect of selected foods and lemon on energy density, pH, viscosity and nutritional quality.

    Science.gov (United States)

    Ejigui, Jeanne; Desrosiers, Therese

    2011-08-01

    The objective of the present study was to use lemon and selected foods to improve the nutritional characteristics, quality and the nutrient content of a traditional complementary porridge made of lactic acid fermented yellow maize. Boiled egg yolk, roasted peanut paste, dry crayfish flour, roasted soybean flour and lemon juice were used as food additions. Amounts of food added were calculated on the basis of World Health Organization estimated energy needs from complementary foods of well-nourished children in developing countries, aged 9-11 months, at four servings per day and a low amount of breast milk energy. The pH and viscosity increased in porridges with food addition, but lemon juice contributed to lowering them. Energy and nutrient densities/100 g porridge improved with food addition regardless of the use of lemon juice. An increase in iron, zinc and calcium in vitro availability was observed (P < 0.05) with the addition of lemon juice.

  1. Encapsulation in alginate and alginate coated-chitosan improved the survival of newly probiotic in oxgall and gastric juice.

    Science.gov (United States)

    Trabelsi, Imen; Bejar, Wacim; Ayadi, Dorra; Chouayekh, Hichem; Kammoun, Radhouane; Bejar, Samir; Ben Salah, Riadh

    2013-10-01

    This study was undertaken to develop an optimum composition model for the microencapsulation of a newly probiotic on sodium alginate using response surface methodology. The individual and interactive effects of three independent variables, namely sodium alginate concentration, biomass concentration, and hardening time, were investigated using Box-Behnken design experiments. A second ordered polynomial model was fitted and optimum conditions were estimated. The optimal conditions identified were 2% for sodium alginate, 10(10)UFC/ml for biomass, and 30 min for hardening time. The experimental value obtained for immobilized cells under these conditions was about 80.98%, which was in close agreement with the predicted value of 82.6%. Viability of microspheres (96%) was enhanced with chitosan as coating materials. The survival rates of free and microencapsulated Lactobacillus plantarum TN8 during exposure to artificial gastrointestinal conditions were compared. The results revealed that the encapsulated cells exhibited significantly higher resistances to artificial intestinal juice (AIJ) and artificial gastric juice (AGJ). Microencapsulation was also noted to effectively protect the strain from heating at 65 °C and refrigerating at 4 °C. Taken together, the findings indicated that microencapsulation conferred important protective effects to L. plantarum against the gastrointestinal conditions encountered during the transit of food.

  2. Arbuscular mycorrhizal fungi native from a Mediterranean saline area enhance maize tolerance to salinity through improved ion homeostasis.

    Science.gov (United States)

    Estrada, Beatriz; Aroca, Ricardo; Maathuis, Frans J M; Barea, José Miguel; Ruiz-Lozano, Juan Manuel

    2013-10-01

    Soil salinity restricts plant growth and productivity. Na(+) represents the major ion causing toxicity because it competes with K(+) for binding sites at the plasma membrane. Inoculation with arbuscular mycorrhizal fungi (AMF) can alleviate salt stress in the host plant through several mechanisms. These may include ion selection during the fungal uptake of nutrients from the soil or during transfer to the host plant. AM benefits could be enhanced when native AMF isolates are used. Thus, we investigated whether native AMF isolated from an area with problems of salinity and desertification can help maize plants to overcome the negative effects of salinity stress better than non-AM plants or plants inoculated with non-native AMF. Results showed that plants inoculated with two out the three native AMF had the highest shoot dry biomass at all salinity levels. Plants inoculated with the three native AMF showed significant increase of K(+) and reduced Na(+) accumulation as compared to non-mycorrhizal plants, concomitantly with higher K(+) /Na(+) ratios in their tissues. For the first time, these effects have been correlated with regulation of ZmAKT2, ZmSOS1 and ZmSKOR genes expression in the roots of maize, contributing to K(+) and Na(+) homeostasis in plants colonized by native AMF.

  3. Recent advances in chitosan-based nanoparticulate pulmonary drug delivery

    Science.gov (United States)

    Islam, Nazrul; Ferro, Vito

    2016-07-01

    The advent of biodegradable polymer-encapsulated drug nanoparticles has made the pulmonary route of administration an exciting area of drug delivery research. Chitosan, a natural biodegradable and biocompatible polysaccharide has received enormous attention as a carrier for drug delivery. Recently, nanoparticles of chitosan (CS) and its synthetic derivatives have been investigated for the encapsulation and delivery of many drugs with improved targeting and controlled release. Herein, recent advances in the preparation and use of micro-/nanoparticles of chitosan and its derivatives for pulmonary delivery of various therapeutic agents (drugs, genes, vaccines) are reviewed. Although chitosan has wide applications in terms of formulations and routes of drug delivery, this review is focused on pulmonary delivery of drug-encapsulated nanoparticles of chitosan and its derivatives. In addition, the controversial toxicological effects of chitosan nanoparticles for lung delivery will also be discussed.

  4. Research of the Mechanism of Enhancing Biological Treatment by Chitosan

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; QIN Bing; CHEN Dong-hui

    2006-01-01

    Chitosan of different molecular weight (M. W. ) was added into SBR bioreactor to treat domestic wastewater. From comparison of treatment efficiency, sludge activity, sludge structure etc., we revealed the mechanism that chitosan enhanced the biological treatment function of activated sludge. The results proved that, chitosan is certain to restrain the reaction of activated sludge, but it do improve the structure of sludge fiocs and increase the treatment efficiency of activated sludge. The bigger the M. W. of chitosan is, the better the efficiency of enhancing biological treatment can be.

  5. Improving the encapsulation efficiency and sustained release behaviour of chitosan/β-lactoglobulin double-coated microparticles by palmitic acid grafting.

    Science.gov (United States)

    Yang, Han-Joo; Lee, Pei Sia; Choe, Jaehyeog; Suh, Seokjin; Ko, Sanghoon

    2017-04-01

    Chitosan (CS) was grafted with 0.1 and 0.5% (w/v) palmitic acid (PA) to improve its encapsulation efficiency (EE) and sustained release characteristics when forming CS microparticles. Thereafter, PA-grafted CS (PA-CS) microparticles were coated with denatured β-lactoglobulin (βlg), which forms an outer protective layer. The possibility of hydrophobic interaction with the hydrophobic substances in the CS microparticles increased as the proportion of the grafted PA increased. EE was measured as 64.79, 83.72, and 85.00% for the non-grafted, 0.1, and 0.5% PA-CS microparticles, respectively. In simulated small intestinal conditions, 4.66 and 17.55% of the core material release in the PA-CS microparticles were sustained after 180min by 0.1, and 0.5% PA grafting, respectively. PA grafting enables the sustained release in simulated gastrointestinal fluids by enhancing the hydrophobic interaction between CS and the hydrophobic core material.

  6. Chitosan-tripolyphosphate nanoparticles: Optimization of formulation parameters for improving process yield at a novel pH using artificial neural networks.

    Science.gov (United States)

    Hashad, Rania A; Ishak, Rania A H; Fahmy, Sherif; Mansour, Samar; Geneidi, Ahmed S

    2016-05-01

    At a novel pH value of the polymeric solution (6.2), variable chitosan (Cs) and sodium tripolyphosphate (TPP) concentrations and mass ratios were optimized to improve the process yield without undesirable particle flocculation. Prepared formulations were characterized in terms of particle size (PS), zeta potential (ZP) and percentage yield (% yield). Artificial neural networks (ANN) were built up and used to identify the parameters that control nanoparticle (NP) size and yield, in addition to being tested for their ability to predict these two experimental outputs. Using these networks, it was found that TPP concentration has the greatest effect on PS and% yield. The most optimum formulation was characterized by a notable process yield reaching 91.5%, a mean hydrodynamic PS 227 nm, ZP+24.13 mv and spherical compact morphology. Successful Cs-TPP interaction in NP formation was confirmed by both Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). This study demonstrated the ability of ANN to predict not only PS of the formed particles but also NP% yield. This may have a great impact on Cs-TPP NPs preparation and can be used to customize the required target formulations.

  7. Chitosan/TiO2 composite membrane improves proliferation and survival of L929 fibroblast cells: Application in wound dressing and skin regeneration.

    Science.gov (United States)

    Behera, Sudhanshu Shekhar; Das, Urmimala; Kumar, Awanish; Bissoyi, Akalabya; Singh, Abhishek Kumar

    2017-05-01

    The microbial infection and growth of fibroblasts are the critical factors for the effective wound healing. The natural polymer-based dressing membranes may mimic extracellular matrix to support the survival, proliferation and differentiation of fibroblasts. The present study deals with the preparation of chitosan/titanium dioxide (CS/TiO2) composite membranes with different degree of TiO2 incorporation, and their characterization in terms of morphology, ultrastructure, thermal behavior and mechanical properties with SEM, FTIR, XRD and tensile strength analyses. The data demonstrated the formation of strong O-Ti-O bonding between TiO2 and CS resulting in superior porosity, mechanical strength, crystallinity and flexibility of the composite membranes. Further, the cyto-compatibility, proliferation, oxidative stress, cell cycle and apoptosis analyses of fibroblast L929 cells demonstrated the enhanced proliferation and survival, and decreased oxidative stress and apoptosis in L929 cells grown on CS/TiO2 membrane incorporated with 025% TiO2. Next, we measured the significant up-regulation in the expression of fibroblast-markers in L929 cells cultured on CS/TiO2 (0.25%) membrane. Furthermore, the CS/TiO2 composite membranes exhibited a superior antibacterial activity against Staphylococcus aureus. Taken together, the data confirmed that CS/TiO2 (0.25%) membrane improved the growth, survival and functional integrity of fibroblasts, and exerted antibacterial activity which may be utilized as potential dressing materials.

  8. Bioactivity of Variant Molecular Weight Chitosan Against Drug-Resistant Bacteria Isolated from Human Wounds.

    Science.gov (United States)

    Bano, Ijaz; Arshad, Muhammad; Ghauri, Muhammad Afzal; Yasin, Tariq; Younus, Muhammad

    2017-03-30

    Chitosan available from crab shells is usually of high molecular weight which may result in reduced efficiency for its antibacterial activity. One of the techniques for improving chitosan antibacterial efficiency is reducing its molecular weight. The irradiation of chitosan by gamma radiations is considered to be one of the most effective and widely used methods for improving its antibacterial activity. Chitosan obtained from crab shells was irradiated with gamma radiations at different doses, and effects on chitosan were analyzed by molecular weight determination and Fourier Transform Infrared spectroscopy. Unirradiated and irradiated chitosans were studied for their antibacterial properties against bacterial pathogens, that is, Pseudomonas aeruginosa (SS29), Escherichia coli (SS2, SS9), Proteus mirabilis (SS77), and Staphylococcus aureus (LM15). Studies have shown that irradiation has significantly developed and improved the antibacterial activity of crab shell chitosan. A correlation was found between bacterial metabolites and antibacterial activity by the analysis for 4-hydroxy-2-alkylquinolines and related metabolites of P. aeruginosa (SS29) in the absence and presence of chitosan by liquid chromatography mass spectrometer, exhibiting the suppression of these virulence factors due to chitosan. Antibacterial efficiency of chitosan was found to be molecular weight dependent and applied concentration of the chitosan. The findings suggest on the use of low-molecular weight chitosan as antibacterial agent in pharmaceutical preparations.

  9. Modification of chitosan with monomethyl fumaric acid in an ionic liquid solution.

    Science.gov (United States)

    Wang, Zhaodong; Zheng, Liuchun; Li, Chuncheng; Zhang, Dong; Xiao, Yaonan; Guan, Guohu; Zhu, Wenxiang

    2015-03-01

    Antibacterial and antioxidant monomethyl fumaric acid (MFA) was selected to modify chitosan, using aqueous solution of an ionic liquid as a homogeneous and green reaction media. The chemical structures of resulting polymers were systematically characterized by (1)H NMR, diffusion ordered spectroscopy, solid (13)C NMR and wide-angle X-ray diffraction. The results show that two kinds of MFA modified chitosan materials with totally different chemical structures have been synthesized. One product was a MF-chitosan salt composed of chitosan cation and MFA anion, which was obtained with the mediation of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide. The other one synthesized with the mediation of EDC was a MF-chitosan amide in which MFA and chitosan are covalently attached. Solubility of chitosan has been improved, and MF-chitosan salt can be readily dissolved in water. The antioxidant activity has been enhanced with the introduction of MFA, irrespective of the chemical structure.

  10. Effect of Spatial Arrangement on Growth and Yield of Cowpea in a Cowpea-maize Intercrop

    Directory of Open Access Journals (Sweden)

    Ocaya, CP.

    2001-01-01

    Full Text Available Cowpea growth and yield performance when intercropped with maize was studied for 3 consecutive seasons under three spatial arrangements, i. e., maize planted at 90 x 30, 100 x 27, and 120 x 22.5 cm, with 2 rows of cowpea between the maize rows. Growth and yield of cowpea was improved significantly by widening maize intra-row distances as compared to the 90 x 30 cm spacing. Hence, intercropped cowpea needs to be sown where maize rows are wide apart, but the maize rows should not be too wide as this would lower the grain yield of maize.

  11. Genetic Analysis in Maize Foundation Parents with Mapping Population and Testcross Population: Ye478 Carried More Favorable Alleles and Using QTL Information Could Improve Foundation Parents

    Science.gov (United States)

    Liu, Yinghong; Hou, Xianbin; Xiao, Qianlin; Yi, Qiang; Bian, Shaowei; Hu, Yufeng; Liu, Hanmei; Zhang, Junjie; Hao, Xiaoqin; Cheng, Weidong; Li, Yu; Huang, Yubi

    2016-01-01

    The development of maize foundation parents is an important part of genetics and breeding research, and applying new genetic information to produce foundation parents has been challenging. In this study, we focused on quantitative trait loci (QTLs) and general combining ability (GCA) of Ye478, a widely used foundation parent in China. We developed three sets of populations for QTL mapping and to analyze the GCA for some agronomic traits. The assessment of 15 traits resulted in the detection of 251 QTLs in six tested environments, with 119 QTLs identified through a joint analysis across all environments. Further, analyses revealed that most favorable alleles for plant type-related traits were from Ye478, and more than half of the favorable alleles for yield-related traits were from R08, another foundation parent used in southwestern China, suggesting that different types of foundation parents carried different favorable alleles. We observed that the GCA for most traits (e.g., plant height and 100-kernel weight) was maintained in the inbred lines descended from the foundation parents. Additionally, the continuous improvement in the GCA of the descendants of the foundation parents was consistent with the main trend in maize breeding programs. We identified three significant genomic regions that were highly conserved in three Ye478 descendants, including the stable QTL for plant height. The GCA for the traits in the F7 generation revealed that the QTLs for the given traits per se were affected by additive effects in the same way in different populations. PMID:27721817

  12. The effect of managing improved fallows of Mucuna pruriens on maize production and soil carbon and nitrogen dynamics in sub-humid Zimbabwe

    NARCIS (Netherlands)

    Whitbread, A.M.; Jiri, O.; Maasdorp, B.

    2004-01-01

    Mucuna pruriens has emerged as a successful forage or green manure legume for use in the smallholder animal-livestock systems of Zimbabwe. The efficiency of N recovery from mucuna residues in subsequent maize crops can be low and the loss of nitrate nitrogen from the soil profile prior to maize N de

  13. Development of monetite/phosphorylated chitosan composite bone cement.

    Science.gov (United States)

    Boroujeni, Nariman Mansouri; Zhou, Huan; Luchini, Timothy J F; Bhaduri, Sarit B

    2014-02-01

    In this article, we report the development of a biodegradable monetite [dicalcium phosphate anhydrous (DCPA), CaHPO4 ]/phosphorylated chitosan (p-chitosan) composite orthopedic cement. The cement pastes showed desirable handling properties, injectability, and washout resistance. The incorporation of p-chitosan powders at 5 wt % shortened the setting time of DCPA and significantly improved the mechanical performance of DCPA cement, increasing the compressive strength almost twice from 11.09 ± 1.85 MPa at 0% chitosan to 23.43 ± 1.47 MPa at 5 wt % p-chitosan. On the other hand, higher p-chitosan content or untreated chitosan incorporation lowered the performance of DCPA cements. The cytocompatibility of the composite cement was investigated in vitro using the preosteoblast cell line MC3T3-E1. An increase in cell proliferation was observed in both DCPA and DCPA-p-chitosan. The results show that both the materials are as cytocompatible as hydroxyapatite. Based on these results, DCPA-p-chitosan composite cement can be considered as potential bone repair material.

  14. Preparation of chitosan gel

    Directory of Open Access Journals (Sweden)

    Lagerge S.

    2012-06-01

    Full Text Available Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  15. Preparation, characterization and antibacterial activity of chitosan and phosphorylated chitosan from cuttlebone of Sepia kobiensis (Hoyle, 1885

    Directory of Open Access Journals (Sweden)

    Annaian Shanmugam

    2016-03-01

    Full Text Available Chitosan is a commercially available derivative of chitin that has been extensively studied for its antimicrobial properties. In order to improve the water solubility and its biological activity, the chemical modification or derivatisation is attempted. In the present investigation, the chitosan prepared from the cuttlebone of Sepia kobiensis was being chemically modified by reacting it with orthophosphoric acid so as to obtain phosphorylated chitosan. Then the chitosan and phosphorylated chitosan were structurally characterized through FT-IR spectroscopy. Further the antibacterial activity of chitosan and phosphorylated chitosan was tested against clinically isolated human pathogens (Gram-positive: Streptococcus sp., Streptococcus pneumoniae and Staphylococcus aureus and Gram-negative: Escherichia coli, Vibrio cholerae, V. alginolyticus, Vibrio parahaemolyticus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella sp. and Proteus vulgaris by well diffusion method and the Minimum Inhibitory Concentration (MIC was also calculated. The results of the present study suggests that the chitosan and phosphorylated chitosan has concentration dependent antibacterial activity with variation against several pathogenic human pathogenic bacterial strains which indicates their possible use as antibacterial agents.

  16. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Luzhong; Dou, Sufeng [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China); Li, Yan [College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Yuan, Ying; Ji, Yawei [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China); Wang, Yaling [College of Chemistry and Chemical Engineering, Nantong University, Nantong 226001 (China); Yang, Yumin, E-mail: yangym@ntu.edu.cn [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China)

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields. - Highlights: ► Chitosan-g-poly(glycolic acid) copolymer was prepared without using a catalyst. ► Degradation rate of copolymer increased dramatically compared with that of chitosan. ► Degradation rate was controlled by the molar ratio of glycolic acid to chitosan. ► In vitro cytotoxicity tests revealed that the copolymer has good biocompatibility. ► The copolymer has a great potential to meet diverse needs in biomedical fields.

  17. Sol-gel encapsulation of pullulanase in the presence of hybrid magnetic (Fe3O4-chitosan) nanoparticles improves thermal and operational stability.

    Science.gov (United States)

    Long, Jie; Li, Xingfei; Zhan, Xiaobei; Xu, Xueming; Tian, Yaoqi; Xie, Zhengjun; Jin, Zhengyu

    2017-02-27

    Pullulanase was sol-gel encapsulated in the presence of magnetic chitosan/Fe3O4 nanoparticles. The resulting immobilized pullulanase was characterized by scanning electron microscopy, vibrating sample magnetometry, Fourier transform infrared spectroscopy and thermogravimetric analysis. The results showed that the addition of pullulanase created a more regular surface on the sol-gel matrix and an enhanced magnetic response to an applied magnetic field. The maximal activity retention (83.9%) and specific activity (291.7 U/mg) of the immobilized pullulanase were observed under optimized conditions including an octyltriethoxysilane:tetraethoxysilane (OTES:TEOS) ratio of 1:2 and enzyme concentration of 0.484 mg/mL sol. The immobilized enzyme exhibited good thermal stability. When the temperature was above 60 °C, the immobilized pullulanase showed significantly higher activity than the free enzyme (p sol-gel encapsulation and co-immobilized by crosslinking-encapsulation retained 52 and 69% of their initial activity after 5 h at 62 °C, respectively, compared to 11% for the free enzyme. Moreover, the stability of the pullulanase was improved by crosslinking-encapsulation, as the enzyme retained more than 85 and 81% of its original activity after 5 and 6 consecutive reuses, respectively, compared to 80 and 72% of its original activity for simple sol-gel encapsulated enzymes. This indicated the leakage of enzyme molecules through the pores of the gel was substantially abated by cross-linking. Such immobilized pullulanase provides high stability and ease of enzyme recovery, characteristics that are advantageous for applications in the food industry that involve continuous starch processing.

  18. Surface functionalization of titanium implants with chitosan-catechol conjugate for suppression of ROS-induced cells damage and improvement of osteogenesis.

    Science.gov (United States)

    Chen, Weizhen; Shen, Xinkun; Hu, Yan; Xu, Kui; Ran, Qichun; Yu, Yonglin; Dai, Liangliang; Yuan, Zhang; Huang, Ling; Shen, Tingting; Cai, Kaiyong

    2017-01-01

    Oxidative stress induced by reactive oxygen species (ROS) overproduction would hinder bone healing process at the interface of bone/implant, yet underlying mechanism remains to be explored. To endow titanium (Ti) substrates with antioxidant activity for enhanced bone formation, multilayered structure composing of chitosan-catechol (Chi-C), gelatin (Gel) and hydroxyapatite (HA) nanofibers was constructed on Ti substrates. Surface wettability and topography of multilayer coated Ti substrates were characterized by water contact angle measurement, scanning electron microscopy and atomic force microscopy, respectively. Chi-C containing multilayer on Ti surface effectively protected osteoblasts from ROS damage, which was revealed by high level of intracellular ROS scavenging activity and reduced oxidative damage on cellular level by regulating the expression of cell adhesion related genes (integrin αv, β3, CDH11 and CDH2). Moreover, it regulated the production of cell adhesive and anti-apoptotic related proteins (p-MYPT1, p-FAK, p-Akt and Bcl-2) and pro-apoptotic critical executioners (Bax and cleaved caspase 3). Beside, the composite multilayer of Chi-C/Gel/HA nanofibers on Ti substrates promoted osteoblasts differentiation, which was evidenced by high expression levels of alkaline phosphatase activity, collagen secretion, ECM mineralization and osteogenesis-related genes expression in vitro. The in vivo experiments of μ-CT analysis, push out test and histochemistry staining further confirmed that Chi-C multilayered implant had great potential for improved early bone healing. Overall, the study offers an effective strategy for the exploration of high quality Ti implants for orthopedic applications.

  19. Ensifer meliloti overexpressing Escherichia coli phytase gene ( appA) improves phosphorus (P) acquisition in maize plants

    Science.gov (United States)

    Sharma, Vikas; Kumar, Ajit; Archana, G.; Kumar, G. Naresh

    2016-10-01

    The Escherichia coli phytase gene appA encoding enzyme AppA was cloned in a broad host range plasmid pBBR1MCS2 ( lac promoter), termed pVA1, and transformed into the Ensifer meliloti 1020. Transformation of pVA1 in Ensifer meliloti { E. m (pVA1)} increased its phosphatase and phytase activity by ˜9- and ˜50-fold, respectively, compared to the transformants containing empty plasmid as control { E. m (pBBR1MCS2)}. The western blot experiments using rabbit anti-AppA antibody showed that AppA is translocated into the periplasm of the host after its expression. Ensifer meliloti harboring AppA protein { E. m (pVA1)} and { E. m (pBBR1MCS2)} could acidify the unbuffered phytate minimal media (pH 8.0) containing Ca-phytate or Na-phytate as sole organic P (Po) source to below pH 5.0 and released P. However, both { E. m (pVA1)} and { E. m (pBBR1MCS2)} neither dropped pH of the medium nor released P when the medium was buffered at pH 8.0 using Tris-Cl, indicating that acidification of medium was important for the enzymatic hydrolysis of phytate. Further experiments proved that maize plants inoculated with { E. m. (pVA1)} showed increase in growth under sterile semi solid agar (SSA) medium containing Na-phytate as sole P source. The present study could be helpful in generating better transgenic bioinoculants harboring phosphate mineralization properties that ultimately promote plant growth.

  20. Ensifer meliloti overexpressing Escherichia coli phytase gene (appA) improves phosphorus (P) acquisition in maize plants.

    Science.gov (United States)

    Sharma, Vikas; Kumar, Ajit; Archana, G; Kumar, G Naresh

    2016-10-01

    The Escherichia coli phytase gene appA encoding enzyme AppA was cloned in a broad host range plasmid pBBR1MCS2 (lac promoter), termed pVA1, and transformed into the Ensifer meliloti 1020. Transformation of pVA1 in Ensifer meliloti {E. m (pVA1)} increased its phosphatase and phytase activity by ∼9- and ∼50-fold, respectively, compared to the transformants containing empty plasmid as control {E. m (pBBR1MCS2)}. The western blot experiments using rabbit anti-AppA antibody showed that AppA is translocated into the periplasm of the host after its expression. Ensifer meliloti harboring AppA protein {E. m (pVA1)} and {E. m (pBBR1MCS2)} could acidify the unbuffered phytate minimal media (pH 8.0) containing Ca-phytate or Na-phytate as sole organic P (Po) source to below pH 5.0 and released P. However, both {E. m (pVA1)} and {E. m (pBBR1MCS2)} neither dropped pH of the medium nor released P when the medium was buffered at pH 8.0 using Tris-Cl, indicating that acidification of medium was important for the enzymatic hydrolysis of phytate. Further experiments proved that maize plants inoculated with {E. m. (pVA1)} showed increase in growth under sterile semi solid agar (SSA) medium containing Na-phytate as sole P source. The present study could be helpful in generating better transgenic bioinoculants harboring phosphate mineralization properties that ultimately promote plant growth.

  1. The role of gibberellins in improving the resistance of tebuconazole-coated maize seeds to chilling stress by microencapsulation

    Science.gov (United States)

    Yang, Lijuan; Yang, Daibin; Yan, Xiaojing; Cui, Li; Wang, Zhenying; Yuan, Huizhu

    2016-01-01

    Chilling stress during germination often causes severe injury. In the present study, maize seed germination and shoot growth under chilling stress were negatively correlated with the dose of tebuconazole in an exponential manner as predicted by the model Y = A + B × e(−x/k). Microencapsulation was an effective means of eliminating potential phytotoxic risk. The gibberellins (GAs) contents were higher after microencapsulation treatment than after conventional treatment when the dose of tebuconazole was higher than 0.12 g AI (active ingredient) kg−1 seed. Further analysis indicated that microencapsulation can stimulate ent-kaurene oxidase (KO) activity to some extent, whereas GA 3-oxidase (GA3ox) and GA 2-oxidase (GA2ox) activities remained similar to those in the control. Genes encoding GA metabolic enzymes exhibited different expression patterns. Transcript levels of ZmKO1 increased in the microcapsule treatments compared to the control. Even when incorporated into microcapsules, tebuconazole led to the upregulation of ZmGA3ox1 at doses of less than 0.12 g AI kg−1 seed and to the upregulation of ZmGA3ox2 when the dose was higher than 0.12 g AI kg−1 seed. With increasing doses of microencapsulated tebuconazole, the transcript levels of ZmGA2ox4, ZmGA2ox5 and ZmGA2ox6 exhibited upward trends, whereas the transcript levels of ZmGA2ox7 exhibited a downward trend. PMID:27819337

  2. Maize silage supplementation to lower quality grass silage improves the intake, apparent digestibility and N retention in wether sheep

    Directory of Open Access Journals (Sweden)

    Ivana Matić

    2009-12-01

    Full Text Available The objective of this experiment was to study the effects of interactions between lower quality grass silage (GS dominated by orchardgrass (Dactylis glomerata L. and maize silage (MS (Zea mays L. on ad libitum intake, digestibility and N retention in wether sheep. The study consisted of four feeding treatments involving GS and MS alone, and GS and MS mixtures in ratios of 67:33 or 33:67 (DM basis fed twice daily. The GS was harvested at the beginning of flowering of orchardgrass (about 35 % of plants were in flower while the MS used was of lower DM and starch concentration (264 g kg-1 fresh weight and 211 g kg-1 DM respectively. Mean DM content of GS was 408 g kg-1 fresh weight. MS was lower in crude protein (CP (62 g kg-1 DM than the GS (98 g kg-1 DM (P<0.001. GS contained larger quantities of neutral detergent fibre (NDF and acid detergent fiber (ADF (P<0.001 than MS. Inclusion of MS in the diet (33 % vs. 67 % had positive linear effects on fresh matter (FM voluntary intake (P<0.05, digestibility of DM, organic matter (OM, digestible OM in the DM (D-value (P<0.05, starch digestibility (P<0.05, N intake (P<0.01, N output in faeces (P<0.05 and absorbed N (P<0.05. A positive associative effect of GS and MS was observed for all intake parameters measured (FM, DM, OM, NDF (quadratic, P<0.05 to P<0.01, digestibility of DM, ADF (quadratic, P<0.05, CP (quadratic, P<0.01, N intake and absorbed N (quadratic, P<0.01. It was concluded that positive interactions of GS and MS were recorded for a limited number of parameters because of the lower quality MS than required for the full benefit of two forages fed together.

  3. The role of gibberellins in improving the resistance of tebuconazole-coated maize seeds to chilling stress by microencapsulation

    Science.gov (United States)

    Yang, Lijuan; Yang, Daibin; Yan, Xiaojing; Cui, Li; Wang, Zhenying; Yuan, Huizhu

    2016-11-01

    Chilling stress during germination often causes severe injury. In the present study, maize seed germination and shoot growth under chilling stress were negatively correlated with the dose of tebuconazole in an exponential manner as predicted by the model Y = A + B × e(‑x/k). Microencapsulation was an effective means of eliminating potential phytotoxic risk. The gibberellins (GAs) contents were higher after microencapsulation treatment than after conventional treatment when the dose of tebuconazole was higher than 0.12 g AI (active ingredient) kg‑1 seed. Further analysis indicated that microencapsulation can stimulate ent-kaurene oxidase (KO) activity to some extent, whereas GA 3-oxidase (GA3ox) and GA 2-oxidase (GA2ox) activities remained similar to those in the control. Genes encoding GA metabolic enzymes exhibited different expression patterns. Transcript levels of ZmKO1 increased in the microcapsule treatments compared to the control. Even when incorporated into microcapsules, tebuconazole led to the upregulation of ZmGA3ox1 at doses of less than 0.12 g AI kg‑1 seed and to the upregulation of ZmGA3ox2 when the dose was higher than 0.12 g AI kg‑1 seed. With increasing doses of microencapsulated tebuconazole, the transcript levels of ZmGA2ox4, ZmGA2ox5 and ZmGA2ox6 exhibited upward trends, whereas the transcript levels of ZmGA2ox7 exhibited a downward trend.

  4. Encapsulation of indole-3-carbinol and 3'3'-diindolylmethane in zein/carboxymethyl chitosan nanoparticles with controlled release property and improved stability

    Science.gov (United States)

    Indole-3-carbinol (I3C) and diindolylmethane (DIM) are two bioactive compounds from Cruciferous vegetables. Their stabilities are the major challenges for their pharmaceutical applications. In this study, zein and zein/carboxymethyl chitosan (zein/CMCS) nanoparticles have been prepared to encapsulat...

  5. Modification of chitosan by swelling and crosslinking using epichlorohydrin as heavy metal Cr (VI) adsorbent in batik industry wastes

    Science.gov (United States)

    Hastuti, B.; Masykur, A.; Hadi, S.

    2016-02-01

    Study on chitosan modification by swelling and crosslinking and its application as a selective adsorbent for heavy metals Cr (VI) in batik industry wastes was done. Swelling is intended to improve chitosan porosity, whereas crosslinking is to increase the resistance of chitosan against acid. Natural samples are generally acidic, thus limiting chitosan application as an adsorbent. Modification of chitosan by combining swelling and crosslinking is expected to increase its adsorption capacity in binding heavy metal ions in water. The modified chitosan was later contacted with Cr (VI) to test its adsorption capacity with a variation of pH and contact time. Finally, application of modified chitosan was done in batik industry waste containing Cr (IV). Based on the results, chitosan-ECH 25% (v/v) was the optimum concentration of crosslinker to adsorb Cr (VI) ions. Modified chitosan has a solubility resistance to acids, even though a strong acid. Modification of chitosan also improved its adsorption capacity to Cr (VI) from 74% (pure chitosan) to 89% with contact time 30 min at pH 3. On the application to the batik wastes, the modified chitosan were able to adsorb Cr (IV) up to the level of 5 ppm. Thus, the modified chitosan has a potential to be applied to as an adsorbent of Cr (VI) in batik industry wastes.

  6. PREPARATION AND PROPERTIES OF CHITOSAN/LIGNIN COMPOSITE FILMS

    Institute of Scientific and Technical Information of China (English)

    Long Chen; Chang-yu Tang; Nan-ying Ning; Chao-yu Wang; Qiang Fu; Qin Zhang

    2009-01-01

    Biodegradable composite films based on chitosan and lignin with various composition were prepared via the solution-casting technique.FT-IR results indicate the existence of hydrogen bonding between chitosan and lignin,and SEM images show that lignin could be well dispersed in chitosan when the content of lignin is below 20 wt% due to the strong interfacial interaction.As a result of strong interaction and good dispersion,the tensile strength,storage modulus,thermal degradation temperature and glass transition temperature of chitosan have been largely improved by adding lignin.Our work provides a simple and cheap way to prepare fully biodegradable chitosan/lignin composites,which could be used as packaging films or wound dressings.

  7. Preparation and properties of polyvinyl acetal sponge modified by chitosan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The polyvinyl acetal sponge modified by chitosan was prepared by adding chitosan/polyvinyl alcohol (PVA) solution during the acetalation reaction of PVA and formaldehyde.The effect of vesicant and chitosan to the pore morphology,water absorption ratio,water absorption rate,expansion time and mechanical properties were studied.The polyvinyl acetal sponge modified by chitosan was used as a hemostatic packing material for the injured rabbit nasal tissue.The hemostatic effect and the healing effect of the modified sponge on the nasal mucosa after nasal surgery were studied.The results indicated that the polyvinyl acetal sponge modified by chitosan has an interconnected pore structure and the wall between large pores also has small pores.The chitosan adhered on the inner surface of the pores.The increased content of vesicant led to an increase in pore diameter,in the water absorption ratio and in expansion time.However,there was only a small change in the water absorption rate and a decrease in tensile strength and compression strength were noted.With an increase in chitosan content,the pore diameter and interconnection of the sponge was reduced.Water absorption ratio,expansion time and water absorption rate decreased,but tensile strength and compression strength improved.Observation of the rabbit nasal tissue after surgical operation suggested that polyvinyl acetal sponge modified by chitosan has an anti-inflammatory,hemostatic and antiadherent characteristic and could promote the healing and functional recovery of rabbit nasal mucosa.

  8. Chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol

    Directory of Open Access Journals (Sweden)

    Shete Amol S

    2012-12-01

    Full Text Available Abstract Background and the purpose of the study Carvedilol nonselective β-adrenoreceptor blocker, chemically (±-1-(Carbazol-4-yloxy-3-[[2-(o-methoxypHenoxy ethyl] amino]-2-propanol, slightly soluble in ethyl ether; and practically insoluble in water, gastric fluid (simulated, TS, pH 1.1, and intestinal fluid (simulated, TS without pancreatin, pH 7.5 Compounds with aqueous solubility less than 1% W/V often represents dissolution rate limited absorption. There is need to enhance the dissolution rate of carvedilol. The objective of our present investigation was to compare chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol. Methods The different formulations were prepared by different methods like solvent change approach to prepare hydrosols, solvent evaporation technique to form solid dispersions and cogrind mixtures. The prepared formulations were characterized in terms of saturation solubility, drug content, infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, powder X-ray diffraction (PXRD, electron microscopy, in vitro dissolution studies and stability studies. Results The practical yield in case of hydrosols was ranged from 59.76 to 92.32%. The drug content was found to uniform among the different batches of hydrosols, cogrind mixture and solid dispersions ranged from 98.24 to 99.89%. There was significant improvement in dissolution rate of carvedilol with chitosan chlorhdyrate as compare to chitosan and explanation to this behavior was found in the differences in the wetting, solubilities and swelling capacity of the chitosan and chitosan salts, chitosan chlorhydrate rapidly wet and dissolve upon its incorporation into the dissolution medium, whereas the chitosan base, less water soluble, would take more time to dissolve. Conclusion This technique is scalable and valuable in manufacturing process in future for enhancement of dissolution of poorly water soluble

  9. Characterization and potential applications of gamma irradiated chitosan and its blends with poly(vinyl alcohol).

    Science.gov (United States)

    Bano, Ijaz; Ghauri, Muhammad Afzal; Yasin, Tariq; Huang, Qingrong; Palaparthi, Annie D'Souza

    2014-04-01

    Naturally available chitosan (CHI), of high molecular weight, results in reduced efficiency of these polymers for antibacterial activity. In this regard, irradiation is a widely used method for achieving reduction in molecular weight of polymers, which may improve some of its characteristics. Chitosan was extracted from crab shells and degraded by gamma radiations. Effect of radiation dose on chitosan was analyzed by Fourier transform infrared (FTIR) spectroscopy. Furthermore, the irradiated chitosan was blended with poly(vinyl alcohol) (PVA) and crosslinked with tetraethylorthosilicate (TEOS) into membranes. The membranes were found to be smooth, transparent and macroporous in structure, exhibiting high tensile strength (TS: 27-47 MPa) and elongation at break (EB: 292.6-407.3%). The effect of molecular weight of chitosan and chitosan blends on antibacterial activity was determined. Irradiated low molecular weight chitosan and membranes showed strong antibacterial activity against Escherichia coli and Bacillus subtilis.

  10. Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

    Directory of Open Access Journals (Sweden)

    Esam A. Elhefian

    2012-01-01

    Full Text Available Chitosan/agar (CS/AG films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA. It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan at all proportions was found to form hydrogel films with enhanced swelling compared to the pure chitosan one. Static water contact angle measurements confirmed the increasing affinity of the blended films towards water suggesting that blending of agar with chitosan improves the wettability of the obtained films.

  11. Effect of organic fertilizers on maize production in Eastern Georgia

    Science.gov (United States)

    Jolokhava, Tamar; Kenchiashvili, Naira; Tarkhnishvili, Maia; Ghambashidze, Giorgi

    2016-04-01

    Maize remains to be the most important cereal crop in Georgia. Total area of arable land under cereal crops production equals to 184 thousands hectares (FAO statistical yearbook, 2014), from which maize takes the biggest share. Leading position of maize among other cereal crops is caused by its dual purpose as food and feed product. In Spite of a relatively high production of maize to other cereals there is still a high demand on it, especially as feed for animal husbandry. The same tendency is seen in organic production, where producers of livestock and poultry products require organically grown maize, the average yield of which is much less than those produced conventionally. Therefore, it is important to increase productivity of maize in organic farms. Current study aimed to improve maize yield using locally produced organic fertilizers and to compare them to the effect of mineral fertilizers. The study was carried out in Eastern Georgia under dry subtropical climate conditions on local hybrid of maize. This is the first attempt to use hybrid maize (developed with organic plant breeding method) in organic field trials in Georgia. The results shown, that grain yield from two different types of organic fertilizers reached 70% of the yields achieved with industrial mineral fertilizers. As on farm level differences between organic and conventional maize production are much severe, the results from the field trials seems to be promising for future improvement of organic cereal crop production.

  12. Reshaping of the maize transcriptome by domestication.

    Science.gov (United States)

    Swanson-Wagner, Ruth; Briskine, Roman; Schaefer, Robert; Hufford, Matthew B; Ross-Ibarra, Jeffrey; Myers, Chad L; Tiffin, Peter; Springer, Nathan M

    2012-07-17

    Through domestication, humans have substantially altered the morphology of Zea mays ssp. parviglumis (teosinte) into the currently recognizable maize. This system serves as a model for studying adaptation, genome evolution, and the genetics and evolution of complex traits. To examine how domestication has reshaped the transcriptome of maize seedlings, we used expression profiling of 18,242 genes for 38 diverse maize genotypes and 24 teosinte genotypes. We detected evidence for more than 600 genes having significantly different expression levels in maize compared with teosinte. Moreover, more than 1,100 genes showed significantly altered coexpression profiles, reflective of substantial rewiring of the transcriptome since domestication. The genes with altered expression show a significant enrichment for genes previously identified through population genetic analyses as likely targets of selection during maize domestication and improvement; 46 genes previously identified as putative targets of selection also exhibit altered expression levels and coexpression relationships. We also identified 45 genes with altered, primarily higher, expression in inbred relative to outcrossed teosinte. These genes are enriched for functions related to biotic stress and may reflect responses to the effects of inbreeding. This study not only documents alterations in the maize transcriptome following domestication, identifying several genes that may have contributed to the evolution of maize, but highlights the complementary information that can be gained by combining gene expression with population genetic analyses.

  13. Chitosan-Silica Hybrid Porous Membranes

    OpenAIRE

    Pandis, C.; S. Madeira; Matos, J.,; Kyritsis, A.; Mano, J. F.; Ribelles, J.L. Gómez

    2014-01-01

    Chitosan–silica porous hybrids were prepared by a novel strategy in order to improve the mechanical properties of chitosan (CHT) in the hydrogel state. The inorganic silica phase was introduced by sol–gel reactions in acidic medium inside the pores of already prepared porous scaffolds. In order to make the scaffolds insoluble in acidic media chitosan was cross-linked by genipin (GEN) with an optimum GEN concentration of 3.2 wt.%. Sol–gel reactions took place with Tetraethylorthosilicate (TEOS...

  14. Improvement of grape and wine phenolic content by foliar application to grapevine of three different elicitors: Methyl jasmonate, chitosan, and yeast extract.

    Science.gov (United States)

    Portu, Javier; López, Rosa; Baroja, Elisa; Santamaría, Pilar; Garde-Cerdán, Teresa

    2016-06-15

    Phenolic compounds play a key role in grape and wine organoleptic properties, being therefore a key parameter in wine quality. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation of phenolic compounds. The aim of this study was to compare the effect of the application of three different elicitors on both grape and wine phenolic content. Methyl jasmonate, chitosan, and a commercial yeast extract were applied to the canopy at veraison and one week later. Results showed that foliar treatments carried out with methyl jasmonate and yeast extract achieved the best results, increasing grape and wine anthocyanin content when compared to the control. Moreover, the application of the yeast elicitor also enhanced grape stilbene content. In contrast, the chitosan treatment did not have a substantial impact on the phenolic compounds. The results of this study indicate that methyl jasmonate and yeast extract applications could be a simple practice to increase grape and wine phenolic content.

  15. Chitosan Removes Toxic Heavy Metal Ions from Cigarette Mainstream Smoke

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wen; XU Ying; WANG Dongfeng; ZHOU Shilu

    2013-01-01

    This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan.Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages.The mainstream smoke particulate matter was collected by a Cambridge filter pad,digested by a microwave digestor,and then analyzed for contents of heavy metal ions,including As(Ⅲ/Ⅴ),Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ),by graphite furnace atomic absorption spectrometry (GFAAS).The results showed that chitosan had a removal effect on Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ).Of these,the percent removal of Ni(Ⅱ) was elevated with an increasing dosage of chitosan.Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ),though with poor efficiency for Pb(Ⅱ).Except As(Ⅲ/Ⅴ),all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight.Nonetheless,the percent removal of Cr(Ⅲ/Ⅵ) peaked with a chitosan molecular weight of 200 kDa,followed by a dramatic decrease with an increasing chitosan molecular weight.Generally,chitosan had different removal effects on four out of five tested metal ions,and the percent removal of Cd(Ⅱ),Pb(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ) was approximately 55%,45%,50%,and 16%,respectively.In a word,chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke,improve cigarette safety,and reduce the harm to smokers.

  16. TRACTION RESISTANCE IN CHITOSAN TREATED COTTON

    Directory of Open Access Journals (Sweden)

    LOX Wouter

    2015-05-01

    Full Text Available Nowadays natural products interest has increased. However, when some products are included on textile fibers, they have no affinity and need some binders or other kind of auxiliaries to improve the yeld of the process, and some of them are not so natural as the product which are binding and consequently the “bio” definition is missed as some of them can be considered as highly pollutant. Chitosan is a common used bonding agent for cotton. It improves the antimicrobial and antifungal activity, improves wound healing and is a non-toxic bonding agent. The biopolymer used in this work is chitosan, which is a deacetylated derivative of chitin. These properties depend on the amount of deacetylation (DD and the Molecular weight (MW. Along with these improving properties, as it requires some acid pH to ve solved the treatment with chitosan can have some decreasing mechanical properties. The aim of that paper is to evaluate the change in breaking force of the treated samples and a change in elongation of those samples. It compared different amounts of concentration of chitosan with non treated cotton. The traction resistance test were performed on a dynamometer. The test was conducted according to the UNE EN ISO 13934-1 standard.

  17. Macrophage interactions with polylactic acid and chitosan scaffolds lead to improved recruitment of human mesenchymal stem/stromal cells: a comprehensive study with different immune cells.

    Science.gov (United States)

    Caires, Hugo R; Esteves, Tiago; Quelhas, Pedro; Barbosa, Mário A; Navarro, Melba; Almeida, Catarina R

    2016-09-01

    Despite the importance of immune cell-biomaterial interactions for the regenerative outcome, few studies have investigated how distinct three-dimensional biomaterials modulate the immune cell-mediated mesenchymal stem/stromal cells (MSC) recruitment and function. Thus, this work compares the response of varied primary human immune cell populations triggered by different model scaffolds and describes its functional consequence on recruitment and motility of bone marrow MSC. It was found that polylactic acid (PLA) and chitosan scaffolds lead to an increase in the metabolic activity of macrophages but not of peripheral blood mononuclear cells (PBMC), natural killer (NK) cells or monocytes. PBMC and NK cells increase their cell number in PLA scaffolds and express a secretion profile that does not promote MSC recruitment. Importantly, chitosan increases IL-8, MIP-1, MCP-1 and RANTES secretion by macrophages while PLA stimulates IL-6, IL-8 and MCP-1 production, all chemokines that can lead to MSC recruitment. This secretion profile of macrophages in contact with biomaterials correlates with the highest MSC invasion. Furthermore, macrophages enhance stem cell motility within chitosan scaffolds by 44% but not in PLA scaffolds. Thus, macrophages are the cells that in contact with engineered biomaterials become activated to secrete bioactive molecules that stimulate MSC recruitment.

  18. Physical stability and moisture sorption of aqueous chitosan-amylose starch films plasticized with polyols

    DEFF Research Database (Denmark)

    Cervera, Mirna Fernández; Karjalainen, Milja; Airaksinen, Sari

    2004-01-01

    The short-term stability and the water sorption of films prepared from binary mixtures of chitosan and native amylose maize starch (Hylon VII) were evaluated using free films. The aqueous polymer solutions of the free films contained 2% (w/w) film formers, glycerol, or erythritol as a plasticizer...... in the crystallinity of the films are evident within a 3-month period of storage, and the changes in the solid state are dependent on the plasticizer and storage conditions. When stored at ambient conditions for 3 months, the aqueous chitosan-amylose starch films plasticized with erythritol exhibited a partly...

  19. Genetic Diversity and Molecular Evolution of Chinese Waxy Maize Germplasm

    Science.gov (United States)

    Zheng, Hongjian; Wang, Hui; Yang, Hua; Wu, Jinhong; Shi, Biao; Cai, Run; Xu, Yunbi; Wu, Aizhong; Luo, Lijun

    2013-01-01

    Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection. PMID:23818949

  20. Genetic diversity and molecular evolution of Chinese waxy maize germplasm.

    Directory of Open Access Journals (Sweden)

    Hongjian Zheng

    Full Text Available Waxy maize (Zea mays L. var. certaina Kulesh, with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima's D and Fu and Li's F* were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection.

  1. Chitosan-coupled solid lipid nanoparticles: Tuning nanostructure and mucoadhesion.

    Science.gov (United States)

    Sandri, Giuseppina; Motta, Simona; Bonferoni, Maria Cristina; Brocca, Paola; Rossi, Silvia; Ferrari, Franca; Rondelli, Valeria; Cantù, Laura; Caramella, Carla; Del Favero, Elena

    2017-01-01

    Solid Lipid Nanoparticles (SLNs) composed of biodegradable physiological lipids have been widely proposed as efficient drug delivery systems, also for ophthalmic administration. Recently, chitosan-associated-SLNs have been developed to further improve the residence time of these colloidal systems in the precorneal area by means of mucoadhesive interaction. In the present study, a one-step preparation protocol was used aiming both at scale-up ease and at stronger coupling between chitosan and SLNs. The resulting particles were chitosan associated-SLNs (CS-SLNs). These nanoparticles were characterized, as compared to both the chitosan-free and the usual chitosan-coated ones, by applying a multi-technique approach: light, neutron and X-ray scattering, Zeta-potential, AFM, calorimetry. It was assessed that, while keeping the features of nano-size and surface-charge required for an efficient vector, these new nanoparticles display a strong and intimate interaction between chitosan and SLNs, far more settled than the usual simple coverage. Moreover, this one-step preparation method allows to obtain a strong and intimate interaction between chitosan and SLNs, firmer than the usual simple coating. This confers to the CS-SLNs an improved mucoadhesion, opening the way for a high-performing ophthalmic formulation.

  2. Hardness methods for testing maize kernels.

    Science.gov (United States)

    Fox, Glen; Manley, Marena

    2009-07-08

    Maize is a highly important crop to many countries around the world, through the sale of the maize crop to domestic processors and subsequent production of maize products and also provides a staple food to subsistance farms in undeveloped countries. In many countries, there have been long-term research efforts to develop a suitable hardness method that could assist the maize industry in improving efficiency in processing as well as possibly providing a quality specification for maize growers, which could attract a premium. This paper focuses specifically on hardness and reviews a number of methodologies as well as important biochemical aspects of maize that contribute to maize hardness used internationally. Numerous foods are produced from maize, and hardness has been described as having an impact on food quality. However, the basis of hardness and measurement of hardness are very general and would apply to any use of maize from any country. From the published literature, it would appear that one of the simpler methods used to measure hardness is a grinding step followed by a sieving step, using multiple sieve sizes. This would allow the range in hardness within a sample as well as average particle size and/or coarse/fine ratio to be calculated. Any of these parameters could easily be used as reference values for the development of near-infrared (NIR) spectroscopy calibrations. The development of precise NIR calibrations will provide an excellent tool for breeders, handlers, and processors to deliver specific cultivars in the case of growers and bulk loads in the case of handlers, thereby ensuring the most efficient use of maize by domestic and international processors. This paper also considers previous research describing the biochemical aspects of maize that have been related to maize hardness. Both starch and protein affect hardness, with most research focusing on the storage proteins (zeins). Both the content and composition of the zein fractions affect

  3. Comprehending smallholder maize enterprises’ profitability with the current maize marketing system in Zimbabwe: A case of Mazowe district

    Directory of Open Access Journals (Sweden)

    John Basera

    2016-06-01

    Full Text Available Maize enterprise profitability is essential for sustainable maize production in smallholder farming. In Zimbabwe a lot of factors including several policy measures implemented in the past are believed to be influencing current maize profitability trends. Literature to confirm some of the crucial factors is limited especially in the smallholder farming sector. In this study we analyze profitability of smallholder maize farmers in Mazowe District of Zimbabwe. We estimate maize enterprise profitability using gross margin analysis, factors driving profitability using linear regression analysis and the influence of tobacco farming adoption on maize enterprise profitability using propensity score matching. We relied on both primary and secondary data from the study area. Results did not show robust outcomes on maize enterprises profitability. Maize profitability was found to be influenced positively by age of household head and selling produce to private buyers and negatively by fertilizer, chemical, and transport costs. Tobacco farming adoption was found to have a positive influence on maize profitability. Based on the results the study recommends the government through its various programs targeting agricultural development and food security to focus on smallholder maize production and marketing with the aim of improving its profitability.

  4. Mixed Compound of DCPTA and CCC Increases Maize Yield by Improving Plant Morphology and Up-Regulating Photosynthetic Capacity and Antioxidants.

    Directory of Open Access Journals (Sweden)

    Yongchao Wang

    Full Text Available DCPTA (2-diethylaminoethyl-3, 4-dichlorophenylether and CCC (2-chloroethyltrimethyl- ammonium chloride have a great effect on maize growth, but applying DCPTA individually can promote the increase of plant height, resulting in the rise of lodging percent. Plant height and lodging percent decrease in CCC-treated plants, but the accumulation of biomass reduce, resulting in yield decrease. Based on the former experiments, the performance of a mixture which contained 40 mg DCPTA and 20 mg CCC as active ingredients per liter of solution, called PCH was tested with applying 40mg/L DCPTA and 20mg/L CCC individually. Grain yield, yield components, internode characters, leaf area per plant, plant height and lodging percent as well as chlorophyll content, chlorophyll fluorescence, enzymatic antioxidants, membranous peroxide and organic osmolyte were analyzed in two years (2011 and 2012, using maize hybrid, Zhengdan 958 (ZD 958 at density of 6.75 plants m-2. CCC, DCPTA and PCH were sprayed on the whole plant leaves at 7 expanded leaves stage and water was used as control. Compared to control, PCH significantly increased grain yield (by 9.53% and 6.68% from 2011 to 2012. CCC significantly decreased kernel number per ear (by 6.78% and 5.69% and thousand kernel weight (TKW (by 8.57% and 6.55% from 2011 to 2012. Kernel number per ear and TKW increased in DCPTA-treated and PCH-treated plants, but showed no significant difference between them. In CCC-treated and PCH-treated plants, internode length and plant height decreased, internode diameter increased, resulting in the significant decline of lodging percent. With DCPTA application, internode diameter increased, but internode length and plant height increased at the same time, resulting in the augment of lodging percent. Bending strength and puncture strength were increased by applying different plant growth regulators (PGRs. In PCH-treated plants, bending strength and puncture strength were greater than other

  5. Novel Amino-Pyridine Functionalized Chitosan Quaternary Ammonium Derivatives: Design, Synthesis, and Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Qing Li

    2017-01-01

    Full Text Available Chemical modification of chitosan is increasingly studied for its potential of providing new applications of chitosan. Here, a group of novel chitosan quaternary ammonium derivatives containing pyridine or amino-pyridine were designed and successfully synthesized through chemical modification of chitosan. Pyridine and amino-pyridine were used as functional groups to improve the antifungal activity of chitosan derivatives. The chitosan derivatives’ antioxidant activity against hydroxyl-radical and 1,1-Diphenyl-2-picrylhydrazyl (DPPH-radical was tested in vitro. The results showed that chitosan derivatives had better water solubility and stronger antioxidant activity compared with chitosan in all assays. Especially, compounds 3C and 3E (with 3-amino pyridine and 2,3-diamino pyridine as substitute respectively exhibited stronger hydroxyl-radical and DPPH-radical scavenging ability than other synthesized compounds. These data demonstrated that the synergistic effect of the amino group and pyridine would improve the antioxidant activity of chitosan derivatives, and the position of the amino group on pyridine could influence the antioxidant property of chitosan derivatives.

  6. STRATEGY OF MAIZE'S CONCENTRATING TO ADVANTAGE AREAS IN JILIN PROVINCE

    Institute of Scientific and Technical Information of China (English)

    JIANG Hui-ming; GU Li-li

    2003-01-01

    Jilin Province is one of the main grain-producing provinces of China, which has dominant position in maize production, by the view of its advantages in policy, location, breed and market. And after entering WTO,some measures have been taken to enhance maize competitive ability. But there are some difficulties in concentrating production to maize advantaged areas. This paper expounds the basis that Jilin Province becomes the advantage area of maize, analyzes the problems and puts forward the supporting policy. Some strategic measures are proposed,as developing comparable advantages, carrying out the strategy of un-equilibrium development and cultivating advantaged product areas of maize to rapidly improve the international competitive ability and productivity of maize in Jilin Province, cast the agricultural predicament off and promote the agricultural development into a new stage.

  7. Improved soil and water conservatory managements for cotton-maize rotation system in the western cotton area of Burkina Faso

    OpenAIRE

    Ouattara, Korodjouma

    2007-01-01

    Integrated soil fertility management combining additions of organic and mineral fertilizers and reduced ploughing frequencies is a prospective option for sustainable cropping systems. In the cotton cultivation area of Burkina Faso the agricultural land is gradually degrading due (at least in part) to increases in mechanization and the use of mineral fertilizers, herbicides and pesticides. The objective of the work underlying this thesis was to test soil management techniques to improve soil f...

  8. The Use of chitosan in The Formation of Silver Nanoparticles, Chitosanic Nanoparticles and Fibrous Structures

    Science.gov (United States)

    Abdelgawad, Abdelrahman Mohamed

    Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The

  9. Synthesis and evaluation of chitosan-Vitamin C complex

    Directory of Open Access Journals (Sweden)

    Tian X

    2009-01-01

    Full Text Available Chitosan is a biocompatible, biodegradable and non-toxic polysaccharide polymer. It dissolves in water only if the pH is lower than 6.5. To extend its range of application, many water-soluble derivatives have therefore been prepared. In this research, chitosan-vitamin C complex was synthesized and characterized with Fourier transformed infrared spectroscopy, differential scanning calorimetry and 1 H-NMR. The solubility of chitosan-vitamin C complex in distilled water was greatly improved. The ·O2 - scavenging activity of chitosan-vitamin C complex was compared with chitosan and vitamin C by measuring the auto-oxidation rate of pyrogallic acid. Results showed that the scavenging activity on ·O2 - by chitosan-vitamin C complex was stronger than that by CS. At low concentrations (< 0.05 mg/ml, the scavenging activity of chitosan-vitamin C complex was stronger than that of vitamin C, but after certain concentrations (>0.1mg/ml, its scavenging activity was lower than that of vitamin C.

  10. Thermal and magnetic properties of chitosan-iron oxide nanoparticles.

    Science.gov (United States)

    Soares, Paula I P; Machado, Diana; Laia, César; Pereira, Laura C J; Coutinho, Joana T; Ferreira, Isabel M M; Novo, Carlos M M; Borges, João Paulo

    2016-09-20

    Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as iron oxide nanoparticles, improving its biocompatibility while extending its range of applications. In this work iron oxide nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan.

  11. The Importance of Chitosan Films in Food Industry

    Directory of Open Access Journals (Sweden)

    Filiz Uçan

    2013-12-01

    Full Text Available Requirement simple technology, low production costs, lack of polluting effects and reliability in terms of health of it is the most important advantages of edible films. Chitosan that extend the shelf life of food and increase the economic efficiency of packaging materials is one of the new materials used for edible films. Chitosan was obtained by deacetylation of chitin which is the most commonly occurred polymer after cellulose in nature, in shells of arthropods such as crab, shrimp, lobster and in cell walls of some bacteria and fungi. Chitosan has the important bioactive properties such as hemostatic, bacteriostatic, fungistatic, spermicidal, anticarcinogenic, anticholesteremic, antacids, antiulcer, wound and bone healing accelerator and stimulating the immune system. As well as these features, the film forming and barrier properties of its, chitosan is made the ideal material for edible films and coatings in antimicrobial characters. Especially, in the protection of qualities and the improving storage times of fruits and vegetables, have been revealed the potential use of chitosan. The coating food with chitosan films reduces the oxygen partial pressure in the package, maintains temperature with moisture transfer between food and its environment, declines dehydration, delays enzymatic browning in fruits and controls respiration. In addition to, chitosan are also used on issues such as the increasing the natural flavour, setting texture, increasing of the emulsifying effect, stabilization of color and deacidification.

  12. PLA/chitosan/keratin composites for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tanase, Constantin Edi, E-mail: etanase@live.com [Faculty of Medical Bioengineering, ‘Grigore T. Popa’ University of Medicine and Pharmacy, 9-13 Kogalniceanu Street, 700454 Iasi (Romania); Spiridon, Iuliana [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania)

    2014-07-01

    Novel composites based on PLA, chitosan and keratin was obtained via blend preparation. The goal of this contribution was to evaluate mechanical and in vitro behavior of the composites. The results point out composites with improved Young modulus and decreased tensile strength, significant increase in hardness (compared to PLA) and a good uptake of the surface properties. Biological assessments using human osteosarcoma cell line on these composites indicate a good viability/proliferation outcome. Hence preliminary results regarding mechanical behavior and in vitro osteoblast response suggest that these composites might have prospective application in medical field. - Highlights: • PLA, chitosan and keratin composites are prepared by blend preparation. • PLA, chitosan and keratin composites present improved mechanical properties and water uptake compare to PLA. • PLA, chitosan and keratin composites present good in vitro behavior.

  13. Impact of acidity and metal ion on the antibacterial activity and mechanisms of β- and α-chitosan.

    Science.gov (United States)

    Bingjun, Qian; Jung, Jooyeoun; Zhao, Yanyun

    2015-03-01

    This study investigated the effects of acidity and metal ion on the antibacterial activity of α- and β-chitosan at different molecular weights (Mw, 22-360 kDa) against Escherichia coli and Listeria innocua through agar well diffusion assay. Spectrophotometric, electrophoretic, and confocal fluorescence microscopy analysis were further employed to evaluate the antibacterial mechanisms probably involved. Increasing pH from 4.0 to 5.0 weakened the antibacterial ability of chitosan as shown by the decreased bacteria growth inhibition zone (BGIZ) from 0.63 to 0.57 cm for β-chitosan (61 kDa) and from 0.62 to 0.57 cm for α-chitosan (30 kDa) against E. coli. All β- and α-chitosan samples showed antibacterial activity against L. innocua, in which 22 kDa β-chitosan and 30 kDa α-chitosan at pH 4.0 had the highest antibacterial activity with BGIZ of 1.22 and 0.98 cm, respectively. Interactive effect between pH and Mw on the antibacterial activity of β-chitosan was observed, but not of α-chitosan. Adding Co(2+) and Ni(2+) significantly improved the antibacterial activity of chitosan, while adding K(+), Na(+), and Li(+) significantly weakened the antibacterial activity of some β- and α-chitosan samples (P antibacterial mechanisms of chitosan.

  14. Synthesis and optimization of chitosan nanoparticles: Potential applications in nanomedicine and biomedical engineering

    OpenAIRE

    Ghadi, Arezou; Mahjoub, Soleiman; Tabandeh, Fatemeh; Talebnia, Farid

    2014-01-01

    Background: Chitosan nanoparticles have become of great interest for nanomedicine, biomedical engineering and development of new therapeutic drug release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity. The aim of the present study was to synthesis and optimize of the chitosan nanoparticles for industrial and biomedical applications. Methods: Fe3O4 was synthesized and optimized as magnetic core nanoparticles and then chitosan ...

  15. Influence of Seed Coating Formulations on Maize Production

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Effects of four coating formulations on maize production were studied. The results showec that all coating formulations had some effects on improving maize seedlings, strengthening the resistance againt diseases and pests and increasing the yields in dtifferent degrees, especially Paxil which increased the com yield by 12.0%, significantly higher than the control.

  16. Effects of laminin-coated carbon nanotube/chitosan fibers on guided neurite growth.

    Science.gov (United States)

    Huang, Yi-Cheng; Hsu, Sung-Hao; Kuo, Wen-Chun; Chang-Chien, Cheng-Lun; Cheng, Henrich; Huang, Yi-You

    2011-10-01

    This study assesses the ability and potential of carbon nanotube (CNT)/chitosan to guide axon re-growth after nerve injuries. The CNT/chitosan fibers were produced via the coagulation and hydrodynamic focusing method. Fiber width and morphology were adjusted using such parameters as syringe pumping rate and the coagulant used. The CNT/chitosan fiber diameters were 50-300 μm for syringe pumping rates of 6-48 mL/h. Polyethylene glycol/NaOH (25%, w/w) solution was a suitable coagulant for forming fibers with small diameters. Physical property tests demonstrate that the CNT/chitosan composites had superior tensile strength and electrical conductivity compared with those of chitosan alone. The MTT and LDH tests reveal that CNT/chitosan composites were not cytotoxic. To improve the neural cell affinity of CNT/chitosan fibers, laminin was incorporated onto fiber surfaces via the oxygen plasma technique; cell adhesion ratio increased significantly from 3.5% to 72.2% with this surface modification. Immunofluorescence staining and SEM imaging indicate that PC12 cells adhered successfully and grew on the laminin (LN)-coated CNT/chitosan films and fibers. Experimental results show that PC12 grown on LN-coated CNT/chitosan fibers in vitro extend longitudinally oriented neurites in a manner similar to that of native peripheral nerves. With the inherent electrical properties of CNTs, oriented CNT/chitosan fibers have a potential for use as nerve conduits in nerve tissue engineering.

  17. Effect Of Chitosan Application On The Performance Of Lentil Genotypes Under Rainfed Conditions

    Directory of Open Access Journals (Sweden)

    Janmohammadi Mohsen

    2014-12-01

    Full Text Available In the current study, influences of chitosan solutions on morphological characteristics, growth and yield components of lentil (Lens culinaris Med. under rainfed conditions have been investigated. A field experiment was conducted in the Northwest of Iran using a split-plot experiment based on a completely randomized design with three replications. The response of twelve genotypes with different origins to chitosan application at the sowing (seed soaking, vegetative and reproductive stage (spraying chitosan onto leaves was evaluated. Results revealed that chitosan application could significantly improve the number of pods per plant, 100-seed weight, grain yield per plant and harvest index in comparison to control plants. The comparison of yield components between chitosan treatments showed that spraying chitosan during the reproductive stage was more efficient than in other stages. However, the responses of the number of pods per plants and grain yield per plants to chitosan treatments were significantly different among the genotypes. Although the highest grain yield was recorded in the 78S 26013 genotype (from Jordan, its response to chitosan treatments was different from the other genotypes and showed the best performance in plants obtained from seed soaked in chitosan solutions. We suggest that the application of chitosan as an agronomic management strategy be further investigated for an efficient technique to induce resistance in lentil plants against biotic and drought stress in semi-arid regions.

  18. Comparison of chitosan nanoparticles and chitosan hydrogels for vaccine delivery

    DEFF Research Database (Denmark)

    Gordon, Sarah; Saupe, Anne; McBurney, Warren

    2008-01-01

    In this work the potential of chitosan nanoparticles (CNP) and thermosensitive chitosan hydrogels as particulate and sustained release vaccine delivery systems was investigated. CNP and chitosan hydrogels were prepared, loaded with the model protein antigen ovalbumin (OVA) and characterised...... of the release of fluorescently-labelled OVA (FITC-OVA) from CNP and chitosan hydrogels in-vitro showed that approximately 50% of the total protein was released from CNP within a period of ten days; release of antigen from chitosan gel occurred in a more sustained manner, with ... released after 10 days. The slow release from gel formulations may be explained by the strong interactions of the protein with chitosan. While OVA-loaded CNP showed no significant immunogenicity, formulations of OVA in chitosan gel were able to stimulate both cell-mediated and humoral immunity in-vivo....

  19. Synthesis of conjugated chitosan and its effect on drug permeation from transdermal patches

    Directory of Open Access Journals (Sweden)

    B K Satheeshababu

    2013-01-01

    Full Text Available The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by Fourier transform-infrared and differential scanning calorimetric analysis. Matrix type transdermal patches of carvedilol were prepared using the different proportions of chitosan and chitosan-thioglycolic acid conjugates (2:0, 1.7:0.3, 1.4:0.6, 1:1, 0.6:1.4 and 0.3:1.7 by solvent casting technique. Prepared matrix type patches were evaluated for their physicochemical characterization followed by in vitro evaluation. Selected formulations were subjected for their ex vivo studies on Wistar albino rat skin and human cadaver skin using the modified Franz diffusion cell. As the proportion of conjugated chitosan increased, the transdermal patches showed increased drug permeation. The mechanism of drug release was found to be nonFickian profiles. The present study concludes that the transdermal patches of carvedilol using conjugated chitosan with different proportions of chitosan were successfully developed to provide improved drug permeation. The transdermal patches can be a good approach to improve drug bioavailability by bypassing the extensive hepatic first-pass metabolism of the drug.

  20. Utilization of chitosan as an antimicrobial agent for pasteurized palm sap (Borassus flabellifer Linn.) during storage.

    Science.gov (United States)

    Naknean, Phisut; Jutasukosol, Keawta; Mankit, Theerarat

    2015-02-01

    The objective of this research was to assess the potential of chitosan for improvement the quality of pasteurized palm sap during storage. First, the effect of chitosan content on sensory attributes was investigated to select suitable concentration of chitosan for further study. Fresh palm sap was enriched with chitosan at various concentrations (0-2 g/L) and pasteurized at 80 °C for 10 min, consequently evaluated by consumers. It was found that samples added chitosan in the range of 0-1.00 g/L were considered acceptable. Thus, the addition chitosan in the concentration of 0-1.00 g/L was chosen for further study. The sample without chitosan addition was used as a control sample. Each selected sample was determined for their qualities during storage at 1 week interval. It was found that lightness and transmittance values of all samples tended to increase during storage. Lower PPO and invertase activity were observed in all chitosan-treated samples compared to control sample. Chitosan could minimize the loss of sucrose and the increase in glucose and fructose content during storage. In addition, an increase in chitosan concentration resulted in the increase in DPPH radical scavenging activity. Furthermore, the addition of chitosan could retard the development of microorganism during storage as demonstrated by lower microbial loads compared to control sample. It can be concluded that a combination of pasteurization with chitosan addition (0.50 g/L) and low temperature storage could preserve palm sap for approximately 6 weeks. Thus, the incorporation of chitosan in palm sap could be used as an alternative way to extend shelf life of pasteurized palm sap.

  1. Bt maize and integrated pest management--a European perspective.

    Science.gov (United States)

    Meissle, Michael; Romeis, Jörg; Bigler, Franz

    2011-09-01

    The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests.

  2. DNA/chitosan electrostatic complex.

    Science.gov (United States)

    Bravo-Anaya, Lourdes Mónica; Soltero, J F Armando; Rinaudo, Marguerite

    2016-07-01

    Up to now, chitosan and DNA have been investigated for gene delivery due to chitosan advantages. It is recognized that chitosan is a biocompatible and biodegradable non-viral vector that does not produce immunological reactions, contrary to viral vectors. Chitosan has also been used and studied for its ability to protect DNA against nuclease degradation and to transfect DNA into several kinds of cells. In this work, high molecular weight DNA is compacted with chitosan. DNA-chitosan complex stoichiometry, net charge, dimensions, conformation and thermal stability are determined and discussed. The influence of external salt and chitosan molecular weight on the stoichiometry is also discussed. The isoelectric point of the complexes was found to be directly related to the protonation degree of chitosan. It is clearly demonstrated that the net charge of DNA-chitosan complex can be expressed in terms of the ratio [NH3(+)]/[P(-)], showing that the electrostatic interactions between DNA and chitosan are the main phenomena taking place in the solution. Compaction of DNA long chain complexed with low molar mass chitosan gives nanoparticles with an average radius around 150nm. Stable nanoparticles are obtained for a partial neutralization of phosphate ionic sites (i.e.: [NH3(+)]/[P(-)] fraction between 0.35 and 0.80).

  3. Eugenol-loaded chitosan nanoparticles: II. Application in bio-based plastics for active packaging.

    Science.gov (United States)

    Woranuch, Sarekha; Yoksan, Rangrong

    2013-07-25

    The aim of the present research was to study the possibility of using eugenol-loaded chitosan nanoparticles as antioxidants for active bio-based packaging material. Eugenol-loaded chitosan nanoparticles were incorporated into thermoplastic flour (TPF) - a model bio-based plastic - through an extrusion process at temperatures above 150°C. The influences of eugenol-loaded chitosan nanoparticles on crystallinity, morphology, thermal properties, radical scavenging activity, reducing power, tensile properties and barrier properties of TPF were investigated. Although the incorporation of 3% (w/w) of eugenol-loaded chitosan nanoparticles significantly reduced the extensibility and the oxygen barrier property of TPF, it provided antioxidant activity and improved the water vapor barrier property. In addition, TPF containing eugenol-loaded chitosan nanoparticles exhibited superior radical scavenging activity and stronger reducing power compared with TPF containing naked eugenol. The results suggest the applicability of TPF containing eugenol-loaded chitosan nanoparticles as an antioxidant active packaging material.

  4. Preparation and characterization of chitosan/nano-hydroxyapatite composite used as bone substitute materials

    Institute of Scientific and Technical Information of China (English)

    Zhang Li; Li Yubao; Zhou Gang; Wu Lan; Mu Yuanhua; Yang Zheng

    2007-01-01

    Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca(OH)2, H3PO4 and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, TGA, bum-out tests and universal matertial testing machine. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there was no phase-separation between the two phases. The addition of n-HA resulted in a decrease of decomposing temperature of chitosan. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured to be about 120MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70.

  5. Maize Genetic Resources

    Science.gov (United States)

    This chapter describes the resources held at the Maize Genetics Cooperation • Stock Center in detail and also provides some information about the North Central Regional Plant Introduction Station (NCRPIS) in Ames, IA, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) in Mexico, and the N...

  6. Use of chitosan to prolong mozzarella cheese shelf life.

    Science.gov (United States)

    Altieri, C; Scrocco, C; Sinigaglia, M; Del Nobile, M A

    2005-08-01

    This study was undertaken to evaluate the feasibility of using chitosan, a natural antimicrobial substance, to improve the preservation of a very perishable cheese. The effectiveness of chitosan to inhibit the growth of spoilage microorganisms in Mozzarella cheese was studied during refrigerated storage. A lactic acid/chitosan solution was added directly to the starter used for Mozzarella cheese manufacturing. Mozzarella cheese samples were stored at 4 degrees C for about 10 d and microbial populations as well as the pH were monitored. Results demonstrated that chitosan inhibited the growth of some spoilage microorganisms such as coliforms, whereas it did not influence the growth of other microorganisms, such as Micrococcaceae, and lightly stimulated lactic acid bacteria.

  7. Inhibition of Inositol-1-phosphate Synthetase in Mycobacterium Tuberculosis by Chitosan-antisense Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    LI Yuanyuan; CHEN Zhifei; ZHANG Hongling; LI Xiaobo; SHEN Jie; LU Shi; XU Shunqing

    2009-01-01

    Oligodeoxynucleotides (ODNs) were combined with the biodegradable polymer chitosan to form chitosan-ODN nanoparticles by complex coacervation, in order to improve the sta-bility and intracellular penetration. The diameter of the nanoparticles was light strength size and ranged between 60 and 219 nm with a mean value of 132 nm, while zeta potential was between +12 and + 20 mV at pH 5.5. The chitosan-ODN nanoparticles could partially protect the encapsulated ODN from nuclease degradation. Moreover, chitosan-ODN nanoparticles were much more effective in inhibiting the proliferation of M.tuberculosis than free ODN.

  8. Antitumour Activity of Chitosan Hydrogen Selenites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Chitosans reacted with selenious acid to prepare chitosan hydrogen selenites, which were found to be growth-inhibitory against sarcoma 180 solid tumor. The results indicated that the activity also depended on the molecular weight of chitosan supports.

  9. Antitumour Acitivty of Chitosan Hydrogen Selenites

    Institute of Scientific and Technical Information of China (English)

    CaiQinQIN; XiaoHaiGAO; 等

    2002-01-01

    Chitosans reacted with selenious acid to prepare chitosan hydrogen selenites, which were found to be growth-inhibitory against sarcoma 180 solid tumor. The results indicated that the activity also depended on the molecular weight of chitosan supports.

  10. A mechanistic based approach for enhancing buccal mucoadhesion of chitosan

    DEFF Research Database (Denmark)

    Meng-Lund, Emil; Muff-Westergaard, Christian; Sander, Camilla

    2014-01-01

    Mucoadhesive buccal drug delivery systems can enhance rapid drug absorption by providing an increased retention time at the site of absorption and a steep concentration gradient. An understanding of the mechanisms behind mucoadhesion of polymers, e.g. chitosan, is necessary for improving the muco......Mucoadhesive buccal drug delivery systems can enhance rapid drug absorption by providing an increased retention time at the site of absorption and a steep concentration gradient. An understanding of the mechanisms behind mucoadhesion of polymers, e.g. chitosan, is necessary for improving...... the mucoadhesiveness of buccal formulations. The interaction between chitosan of different chain lengths and porcine gastric mucin (PGM) was studied using a complex coacervation model (CCM), isothermal titration calorimetry (ITC) and a tensile detachment model (TDM). The effect of pH was assessed in all three models...... and the approach to add a buffer to chitosan based drug delivery systems is a means to optimize and enhance buccal drug absorption. The CCM demonstrated optimal interactions between chitosan and PGM at pH 5.2. The ITC experiments showed a significantly increase in affinity between chitosan and PGM at pH 5...

  11. Low molecular weight chitosan conjugated with folate for siRNA delivery in vitro: optimization studies

    Directory of Open Access Journals (Sweden)

    Shi Q

    2012-11-01

    Full Text Available Julio C Fernandes,1 Xingping Qiu,2 Francoise M Winnik,2 Mohamed Benderdour,1 Xiaoling Zhang,3 Kerong Dai,3 Qin Shi11Orthopaedics Research Laboratory, Research Centre, Sacré-Coeur Hospital, 2Department of Physical Chemistry and Polymer Science, Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada; 3Orthopaedic Cellular and Molecular Biology Laboratories, Institute of Health Sciences, Chinese Academy of Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, ChinaAbstract: The low transfection efficiency of chitosan is one of its drawbacks as a gene delivery carrier. Low molecular weight chitosan may help to form small-sized polymer-DNA or small interfering RNA (siRNA complexes. Folate conjugation may improve gene transfection efficiency because of the promoted uptake of folate receptor-bearing cells. In the present study, chitosan was conjugated with folate and investigated for its efficacy as a delivery vector for siRNA in vitro. We demonstrate that the molecular weight of chitosan has a major influence on its biological and physicochemical properties, and very low molecular weight chitosan (below 10 kDa has difficulty in forming stable complexes with siRNA. In this study, chitosan 25 kDa and 50 kDa completely absorbed siRNA and formed nanoparticles (≤220 nm at a chitosan to siRNA weight ratio of 50:1. The introduction of a folate ligand onto chitosan decreased nanoparticle toxicity. Compared with chitosan-siRNA, folate-chitosan-siRNA nanoparticles improved gene silencing transfection efficiency. Therefore, folate-chitosan shows potential as a viable candidate vector for safe and efficient siRNA delivery.Keywords: nonviral vector, chitosan, gene delivery, folate-targeted, siRNA

  12. Improvement of chitosan derivatization for the immobilization of bacillus circulans β-galactosidase and its further application in galacto-oligosaccharide synthesis.

    Science.gov (United States)

    Urrutia, Paulina; Bernal, Claudia; Wilson, Lorena; Illanes, Andrés

    2014-10-15

    Chitosan was derivatized by two methodologies to design a robust biocatalyst of immobilized Bacillus circulans β-galactosidase from a low-cost support for its further application in the synthesis of galacto-oligosaccharides (GOS). In the first one, chitosan was derivatized by cross-linking with glutaraldehyde and activated with epichlorohydrin; in the second one, cross-linking and activation were done with epichlorohydrin in a two-step process, favoring first support cross-linking and then support functionalization (C-EPI-EPI). Epoxy groups were hydrolyzed and oxidized, obtaining two supports activated with different aldehyde concentrations (100-250 μmol/g). The expressed activity and stability of the immobilized biocatalysts varied according to the derivatization methodology, showing that both the cross-linking agent and the activation degree are key parameters in the final biocatalyst performance. The best compromise between expressed activity and thermal stability was obtained using C-EPI-EPI with 200 μmol of aldehyde groups per gram of support. The immobilization conditions were optimized, obtaining a biocatalyst with 280 IU/g, immobilization yields in terms of activity and protein of 17.3 ± 0.4 and 61.5 ± 3.9%, respectively, and a high thermal stability, with a half-life of 449 times the value of the soluble enzyme. The biocatalyst was applied to the synthesis of GOS in repeated batch operation without affecting the product composition. Four successive batches were required for obtaining a cumulative specific productivity higher than the one obtained with the soluble enzyme.

  13. Pectin-chitosan-PVA nanofibrous scaffold made by electrospinning and its potential use as a skin tissue scaffold.

    Science.gov (United States)

    Lin, Hsin-Yi; Chen, Hsin-Hung; Chang, Shih-Hsin; Ni, Tsung-Sheng

    2013-01-01

    Scaffolds made of chitosan nanofibers are often too mechanically weak for their application and often their manufacturing processes involve the use of harmful and flammable organic solvents. In the attempt to improve the mechanical properties of nanofibrous scaffolds made of chitosan without the use of harmful chemicals, pectin, an anionic polymer was blended with chitosan, a cationic polymer, to form a polyelectrolyte complex and electrospun into nanofibers for the first time. The electrospun chitosan-pectin scaffolds, when compared to electrospun chitosan scaffolds, had a 58% larger diameter, a 21% higher Young's modulus, a 162% larger strain at break, and a 104% higher ultimate tensile strength. Compared to the chitosan scaffolds, the chitosan-pectin scaffolds' swelling ratios decreased by 55% after 60 min in a saline solution and more quickly released the preloaded tetracycline HCl. The L929 fibroblast cells proliferated slightly slower on the chitosan-pectin scaffolds than on the chitosan scaffolds. Nonetheless, cells on both materials deposited similar levels of extracellular type I collagen on a per DNA basis. In conclusion, a novel chitosan-pectin nanofibrous scaffold with superior mechanical properties than a chitosan nanofibrous scaffold was successfully made without the use of harmful solvents.

  14. Impact of chitosan composites and chitosan nanoparticle composites on various drug delivery systems: A review

    OpenAIRE

    M. Abd Elgadir; Md.Salim Uddin; Sahena Ferdosh; Aishah Adam; Ahmed Jalal Khan Chowdhury; Md. Zaidul Islam Sarker

    2015-01-01

    Chitosan is a promising biopolymer for drug delivery systems. Because of its beneficial properties, chitosan is widely used in biomedical and pharmaceutical fields. In this review, we summarize the physicochemical and drug delivery properties of chitosan, selected studies on utilization of chitosan and chitosan-based nanoparticle composites in various drug delivery systems, and selected studies on the application of chitosan films in both drug delivery and wound healing. Chitosan is considere...

  15. An Improved Chitosan Coating Method for Bacteriostasis and Preservation of Grass Carp During Refrigerated Storage%改良壳聚糖涂膜技术对草鱼肉抑菌保鲜效果的研究

    Institute of Scientific and Technical Information of China (English)

    王发祥; 王满生; 刘永乐; 俞健; 王建辉; 李向红

    2013-01-01

    Chitosan coating is a new preservation technology with good preservation effect and superiority,but has some disadvantages,such as slow speed of film forming,difficulty in the operating and controlling the film thickness.Thus,improving the composition of coating solution and the coating technology is important for its preservation effect.The improved preservative and antibacterial effects on refrigerated grass carp meat was investigated by using new coating method with adding volatile ethanol.By varying the concentrations of ethanol and chitosan in coating solution,as well as coating methods,the total bacteria colony and TVB-N of the fish during its cold storage were studied.The results showed that the coating solution containing 75% ethanol had better antimicrobial and bactericidal effects with a decrease of>51% in initial bacterial count of fresh fish meat.The best chitosan concentration was 1.0% comprehensively considering its film-forming ability and antibacterial effect.In addition,the coating methods showed little difference in affecting the preservation of Grass carp,while spray coating pattern was relatively convenient in operation and economical in coating solution.These findings demonstrated that spray coating using acidic chitosan solution containing 75% ethanol was an effectvely new fish preservation technology.%壳聚糖溶液涂膜是一种新兴的保鲜技术,具有较好的保鲜效果和优越性,但尚存在成膜较慢、不易操作、膜层厚度难控制等缺点,因而改善涂膜液的组成和涂膜技术是涂膜保鲜的关键.本文研究了新的涂膜方式和添加易挥发的乙醇来改进壳聚糖涂膜液的成膜和抑菌效果.通过改变不同乙醇浓度、壳聚糖浓度和涂膜方式等条件,分析其对冷藏过程中草鱼肉的微生物菌落总数和TVB-N值的影响.结果表明,涂膜溶液中含有75%的乙醇时,不仅对冷藏草鱼肉的抑菌效果好,而且还具有减菌作用,使样品初始微

  16. TECHNICAL EFFICIENCY OF TECHNOLOGY ADOPTION BY MAIZE FARMERS IN THREE AGRO-ECOLOGICAL ZONES OF GHANA

    Directory of Open Access Journals (Sweden)

    Victor OWUSU

    2016-11-01

    Full Text Available Using a farm household data from 3 agroecological zones of Ghana, this paper investigates the causal relationship between the adoption of improved maize variety and technical efficiency or productivity. The empirical results show a positive relationship between the adoption of improved maize variety and technical efficiency or productivity of farmers in the Semi-deciduous forest and Guinea Savannah zones. Generally, adopters of improved maize variety are about 6% to 8% more efficient than non-adopters. The estimated percentage increase in productivity due to the adoption of improved maize variety is about 53%. In the Semi-deciduous forest agroecological zone, adopters of improved maize variety are about 25% to 36% more efficient than non-adopters whilst in the Guinea Savannah agroecological zone, adopters of improved maize variety are about 15% to 26% more efficient than non-adopters. The estimated percentage increase in productivity due to adoption of the improved maize variety is about 8% in the Semi-deciduous forest zone and about 11% in the Guinea Savannah zone. The impact of adoption on technical efficiency in the Transitional zone is however negative. Adopters of improved maize variety are 7% to 8% less efficient than non-adopters and the estimated percentage decrease in productivity due to adoption of the improved maize variety is about 15%. Food safety net policies should pay attention to increased development and dissemination of improved crop varieties suitable to different agroecological zones.

  17. Thiolated chitosan nanoparticles: transfection study in the Caco-2 differentiated cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Martien, Ronny [Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innrain 52, Josef Moeller Haus, A-6020 Innsbruck (Austria); Loretz, Brigitta [Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innrain 52, Josef Moeller Haus, A-6020 Innsbruck (Austria); Sandbichler, Adolf Michael [Institute of Zoology, Leopold-Franzens-University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Schnuerch, Andreas Bernkop [Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innrain 52, Josef Moeller Haus, A-6020 Innsbruck (Austria)

    2008-01-30

    The aim of this study was to monitor the expression of secreted protein in differentiated Caco-2 cells after transfection with nanoparticles, in order to improve gene delivery. Based on unmodified chitosan and thiolated chitosan conjugates, nanoparticles with the gene reporter pSEAP (recombinant Secreted Alkaline Phosphatase) were generated at pH 4.0. Transfection studies of thiolated chitosan in Caco-2 cells during the exponential growth phase and differentiation growth phase of the cells led to a 5.0-fold and 2.0-fold increase in protein expression when compared to unmodified chitosan nanoparticles. The mean particle size for both unmodified chitosan and cross-linked thiolated chitosan nanoparticles is 212.2 {+-} 86 and 113.6 {+-} 40 nm, respectively. The zeta potential of nanoparticles was determined to be 7.9 {+-} 0.38 mV for unmodified chitosan nanoparticles and 4.3 {+-} 0.74 mV for cross-linked thiolated chitosan nanoparticles. Red blood cell lysis evaluation was used to evaluate the membrane damaging properties of unmodified and thiolated chitosan nanoparticles and led to 4.61 {+-} 0.36% and 2.29 {+-} 0.25% lysis, respectively. Additionally, cross-linked thiolated chitosan nanoparticles were found to exhibit higher stability toward degradation in gastric juices. Furthermore the reversible effect of thiolated chitosan on barrier properties was monitored by measuring the transepithelial electrical resistance (TEER) and is supported by immunohistochemical staining for the tight junction protein claudin. According to these results cross-linked thiolated chitosan nanoparticles have the potential to be used as a non-viral vector system for gene therapy.

  18. Chitosan and chemically modified chitosan beads for acid dyes sorption

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.

  19. Chitosan nanoparticle based delivery systems for sustainable agriculture.

    Science.gov (United States)

    Kashyap, Prem Lal; Xiang, Xu; Heiden, Patricia

    2015-01-01

    Development of technologies that improve food productivity without any adverse impact on the ecosystem is the need of hour. In this context, development of controlled delivery systems for slow and sustained release of agrochemicals or genetic materials is crucial. Chitosan has emerged as a valuable carrier for controlled delivery of agrochemicals and genetic materials because of its proven biocompatibility, biodegradability, non-toxicity, and adsorption abilities. The major advantages of encapsulating agrochemicals and genetic material in a chitosan matrix include its ability to function as a protective reservoir for the active ingredients, protecting the ingredients from the surrounding environment while they are in the chitosan domain, and then controlling their release, allowing them to serve as efficient gene delivery systems for plant transformation or controlled release of pesticides. Despite the great progress in the use of chitosan in the area of medical and pharmaceutical sciences, there is still a wide knowledge gap regarding the potential application of chitosan for encapsulation of active ingredients in agriculture. Hence, the present article describes the current status of chitosan nanoparticle-based delivery systems in agriculture, and to highlight challenges that need to be overcome.

  20. Bubble template fabrication of chitosan/poly(vinyl alcohol) sponges for wound dressing applications.

    Science.gov (United States)

    Chen, Changfeng; Liu, Li; Huang, Tao; Wang, Qiong; Fang, Yue'e

    2013-11-01

    The present investigation involves the synthesis of chitosan based composite sponges in view of their applications in wound dressing, antibacterial and haemostatic. A facile CO2 bubbles template freeze-drying method was developed for the fabrication of macroporous chitosan-poly(vinyl alcohol) (PVA) composite sponges with a typical porosity of 50% and pore size of 100-300 μm. Effects of the content of cross-linking agent and PVA on morphology, mechanical properties, water uptake and moisture permeability were examined. The macroporous chitosan/PVA composite sponges exhibited an enhanced water absorption capacity over those reported microporous chitosan sponges prepared using traditional free-drying methods. Improved strength and flexibility of the chitosan sponges were observed with the presence of PVA. Further, the antibacterial and haemostatic activities have been also demonstrated. The chitosan/PVA composite sponges showed higher haemostatic activity than pure chitosan sponges and solutions. Erythrocytes cells bind first to the surface of chitosan polymer in the sponges and then promote the binding with other cells in the solution. The chitosan/PVA sponges of high liquid absorbing, appropriate moisture permeability, antimicrobial property and unique haemostatic behavior can be used for wound dressing applications.

  1. A sulfuric-lactic acid process for efficient purification of fungal chitosan with intact molecular weight.

    Science.gov (United States)

    Naghdi, Mitra; Zamani, Akram; Karimi, Keikhosro

    2014-02-01

    The most recent method of fungal chitosan purification, i.e., two steps of dilute sulfuric acid treatment, pretreatment of cell wall at room temperature for phosphate removal and extraction of chitosan from the phosphate free cell wall at high temperature, significantly reduces the chitosan molecular weight. This study was aimed at improvement of this method. In the pretreatment step, to choose the best conditions, cell wall of Rhizopus oryzae, containing 9% phosphate, 10% glucosamine, and 21% N-acetyl glucosamine, was treated with sulfuric, lactic, acetic, nitric, or hydrochloric acid, at room temperature. Sulfuric acid showed the best performance in phosphate removal (90%) and cell wall recovery (89%). To avoid depolymerisation of chitosan, hot sulfuric acid extraction was replaced with lactic acid treatment at room temperature, and a pure fungal chitosan was obtained (0.12 g/g cell wall). Similar pretreatment and extraction processes were conducted on pure shrimp chitosan and resulted in a chitosan recovery of higher than 87% while the reduction of chitosan viscosity was less than 15%. Therefore, the sulfuric-lactic acid method purified the fungal chitosan without significant molecular weight manipulation.

  2. Diversity in global maize germplasm: characterization and utilization.

    Science.gov (United States)

    Prasanna, B M

    2012-11-01

    Maize (Zea mays L.) is not only of worldwide importance as a food, feed and as a source of diverse industrially important products, but is also a model genetic organism with immense genetic diversity. Although it was first domesticated in Mexico, maize landraces are widely found across the continents. Several studies in Mexico and other countries highlighted the genetic variability in the maize germplasm. Applications of molecular markers, particularly in the last two decades, have led to new insights into the patterns of genetic diversity in maize globally, including landraces as well as wild relatives (especially teosintes) in Latin America, helping in tracking the migration routes of maize from the centers of origin, and understanding the fate of genetic diversity during maize domestication. The genome sequencing of B73 (a highly popular US Corn Belt inbred) and Palomero (a popcorn landrace in Mexico) in the recent years are important landmarks in maize research, with significant implications to our understanding of the maize genome organization and evolution. Next-generation sequencing and high-throughput genotyping platforms promise to further revolutionize our understanding of genetic diversity and for designing strategies to utilize the genomic information for maize improvement. However, the major limiting factor to exploit the genetic diversity in crops like maize is no longer genotyping, but high-throughput and precision phenotyping. There is an urgent need to establish a global phenotyping network for comprehensive and efficient characterization of maize germplasm for an array of target traits, particularly for biotic and abiotic stress tolerance and nutritional quality. 'Seeds of Discovery' (SeeD), a novel initiative by CIMMYT with financial support from the Mexican Government for generating international public goods, has initiated intensive exploration of phenotypic and molecular diversity of maize germplasm conserved in the CIMMYT Gene Bank; this is

  3. Diversity in global maize germplasm: Characterization and utilization

    Indian Academy of Sciences (India)

    B M Prasanna

    2012-11-01

    Maize (Zea mays L.) is not only of worldwide importance as a food, feed and as a source of diverse industrially important products, but is also a model genetic organism with immense genetic diversity. Although it was first domesticated in Mexico, maize landraces are widely found across the continents. Several studies in Mexico and other countries highlighted the genetic variability in the maize germplasm. Applications of molecular markers, particularly in the last two decades, have led to new insights into the patterns of genetic diversity in maize globally, including landraces as well as wild relatives (especially teosintes) in Latin America, helping in tracking the migration routes of maize from the centers of origin, and understanding the fate of genetic diversity during maize domestication. The genome sequencing of B73 (a highly popular US Corn Belt inbred) and Palomero (a popcorn landrace in Mexico) in the recent years are important landmarks in maize research, with significant implications to our understanding of the maize genome organization and evolution. Next-generation sequencing and high-throughput genotyping platforms promise to further revolutionize our understanding of genetic diversity and for designing strategies to utilize the genomic information for maize improvement. However, the major limiting factor to exploit the genetic diversity in crops like maize is no longer genotyping, but high-throughput and precision phenotyping. There is an urgent need to establish a global phenotyping network for comprehensive and efficient characterization of maize germplasm for an array of target traits, particularly for biotic and abiotic stress tolerance and nutritional quality. ‘Seeds of Discovery’ (SeeD), a novel initiative by CIMMYT with financial support from the Mexican Government for generating international public goods, has initiated intensive exploration of phenotypic and molecular diversity of maize germplasm conserved in the CIMMYT Gene Bank; this

  4. Isolation and identification of indigenous plant growth promoting rhizobacteria from Himalayan region of Kashmir and their effect on improving growth and nutrient contents of maize (Zea mays L.).

    Science.gov (United States)

    Zahid, Mahwish; Abbasi, M Kaleem; Hameed, Sohail; Rahim, Nasir

    2015-01-01

    Introduction and exploitation of plant growth promoting rhizobacteria (PGPR) in agro-ecosystems enhance plant-microbes interactions that may affect ecosystems sustainability, agricultural productivity, and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L.) from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK), Pakistan. A total of 100 isolates were isolated from these sites, out of which eight (HJR1, HJR2, HJR3, HJR4, HJR5, MR6, HJR7, HJR8) were selected in vitro for their plant growth promoting ability (PGPA) including phosphorus solubilization, indole-3-acetic acid (IAA) production and N2 fixation. The 16S rRNA gene sequencing technique was used for molecular identity and authentication. Isolates were then further tested for their effects on growth and nutrient contents of maize (Z. mays L.) under pouch and pot conditions. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to Pseudomonas and Bacillus genera. The isolates promoted plant growth by solubilizing soil P which ranged between 19.2 and 35.6 μg mL(-1). The isolates HJR1, HJR2, HJR3, and HJR5 showed positive activity in acetylene reduction assay showing their N2-fixation potential. All eight isolates showed the potential to produce IAA in the range of 0.9-5.39 μg mL(-1) and promote plant growth. Results from a subsequent pot experiment indicated PGPRs distinctly increased maize shoot and root length, shoot and root dry weight, root surface area, leaf surface area, shoot and root N and P contents. Among the eight isolates, HR3 showed a marked P-solubilizing activity, plant growth-promoting attributes, and the potential to be developed as a biofertilizers for integrated nutrient management strategies.

  5. Isolation and Identification of Indigenous Plant Growth Promoting Rhizobacteria from Himalayan Region of Kashmir and their Effect on Improving Growth and Nutrient Contents of Maize (Zea Mays L.

    Directory of Open Access Journals (Sweden)

    Mahwish eZahid

    2015-03-01

    Full Text Available IIntroduction and exploitation of plant growth promoting rhizobacteria (PGPR in agro-ecosystems enhance plant-microbes interactions that may affect ecosystems sustainability, agricultural productivity and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L. from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK, Pakistan. A total of one hundred isolates were isolated from these sites, out of which eight (HJR1, HJR2, HJR3, HJR4, HJR5, MR6, HJR7, HJR8 were selected in vitro for their plant growth promoting ability (PGPA including phosphorus solubilization, indole acetic acid (IAA production and N2 fixation. The 16S rRNA gene sequencing technique was used for molecular identity and authentication. Isolates were then further tested for their effects on growth and nutrient contents of maize (Zea mays L. under pouch and pot conditions. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to Pseudomonas and Bacillus genera. The isolates promoted plant growth by solubilizing soil P which ranged between 19.2 and 35.6 µgmL−1. The isolates HJR1, HJR2, HJR3 and HJR5 showed positive activity in acetylene reduction assay showing their N2-fixation potential. All eight isolates showed the potential to produce IAA in the range of 0.9−5.39 µgmL−1 and promote plant growth. Results from a subsequent pot experiment indicated PGPRs distinctly increased maize shoot and root length, shoot and root dry weight, root surface area, leaf surface area, shoot and root N and P contents. Among the eight isolates, HR3 showed a marked P-solubilizing activity, plant growth-promoting attributes, and the potential to be developed as a biofertilizers for integrated nutrient management strategies

  6. Improving the osteogenesis of human bone marrow mesenchymal stem cell sheets by microRNA-21-loaded chitosan/hyaluronic acid nanoparticles via reverse transfection

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-05-01

    Full Text Available Zhongshan Wang,1 Guangsheng Wu,2,3 Mengying Wei,4 Qian Liu,1 Jian Zhou,1 Tian Qin,1 Xiaoke Feng,1 Huan Liu,1 Zhihong Feng,1 Yimin Zhao1 1State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, 2State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi’an, 3Qingdao First Sanatorium, Jinan Military Region, Qingdao, Shandong Province, 4Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi’an, People’s Republic of China Abstract: Cell sheet engineering has emerged as a novel approach to effectively deliver seeding cells for tissue regeneration, and developing human bone marrow mesenchymal stem cell (hBMMSC sheets with high osteogenic ability is a constant requirement from clinics for faster and higher-quality bone formation. In this work, we fabricated biocompatible and safe chitosan (CS/hyaluronic acid (HA nanoparticles (NPs to deliver microRNA-21 (miR-21, which has been proved to accelerate osteogenesis in hBMMSCs; then, the CS/HA/miR-21 NPs were cross-linked onto the surfaces of culture plates with 0.2% gel solution to fabricate miR-21-functionalized culture plates for reverse transfection. hBMMSC sheets were induced continuously for 14 days using a vitamin C-rich method on the miR-21-functionalized culture plates. For the characterization of CS/HA/miR-21 NPs, the particle size, zeta potential, surface morphology, and gel retardation were sequentially investigated. Then, the biological effects of hBMMSC sheets on the miR-21-functionalized culture plates were evaluated. The assay results demonstrated that the hBMMSC sheets could be successfully induced via the novel

  7. MaizeGDB, the community database for maize genetics and genomics

    OpenAIRE

    2004-01-01

    The Maize Genetics and Genomics Database (MaizeGDB) is a central repository for maize sequence, stock, phenotype, genotypic and karyotypic variation, and chromosomal mapping data. In addition, MaizeGDB provides contact information for over 2400 maize cooperative researchers, facilitating interactions between members of the rapidly expanding maize community. MaizeGDB represents the synthesis of all data available previously from ZmDB and from MaizeDB—databases that have been superseded by Maiz...

  8. Adherence of paclitaxel drug in magnetite chitosan nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Escobar Zapata, Edna V.; Martinez Perez, Carlos A.; Rodriguez Gonzalez, Claudia A.; Castro Carmona, Javier S. [Instituto de Ingenieria y Tecnologia, Universidad Autonoma de Ciudad Juarez, Ave. Del Charro 610 norte, Col. Partido Romero, C.P. 32320, Cd. Juarez Chihuahua (Mexico); Quevedo Lopez, Manuel A. [Departamento de Polimeros y Materiales, Universidad de Sonora, Blvd. Luis Encinas y Rosales, Hermosillo, Sonora (Mexico); Garcia-Casillas, Perla E., E-mail: pegarcia@uacj.mx [Instituto de Ingenieria y Tecnologia, Universidad Autonoma de Ciudad Juarez, Ave. Del Charro 610 norte, Col. Partido Romero, C.P. 32320, Cd. Juarez Chihuahua (Mexico)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Chitosan silica magnetite adsorbs antineoplastic drug. Black-Right-Pointing-Pointer Silica coating improve the drug adherence. - Abstract: Cancer treatment is a big challenge in medicine where chemotherapies and radiotherapies are aggressive and poorly effective having side effects as delirium, fatigue, insomnia, nausea and vomiting which are common problems for cancer patients. For this reason, during the last two decades, many researchers have developed several techniques to improve the current therapies; one of them is the functionalization of magnetic nanoparticles for drug delivery. In this work, magnetic nanoparticles with an average crystallite size 21.8 nm were covered in a core/shell type; magnetite/silica, magnetite/chitosan, and a double shell magnetite/silica/chitosan were developed for attaching an antineoplastic drug. The mechanism for the functionalization of the nanoparticles with a single and double shell was studied with Fourier transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The adherence of an antineoplastic drug, paclitaxel, onto functionalized nanoparticles was analyzed with a UV-Visible spectroscopy at a wavelength of 253 nm. It was found that the adherence of the drug is improved up to 18% when magnetite nanoparticles are coated with a single chitosan shell, and when the nanoparticles are coated with a silica/chitosan shell the adherence increases up to 29%.

  9. Improvement of application properties of chitosan-based food packaging films by lavender essential oil%薰衣草精油改善壳聚糖基食品包装膜的应用品质

    Institute of Scientific and Technical Information of China (English)

    张赟彬; 王景文; 李月霞; 王一非; 姜萍萍; 刘笑宇

    2014-01-01

    potential biodegradable material due to its edibility, film-forming capacity, non-toxicity, antibacterial activity, biocompatibility and biodegradability. Traditional chitosan-based composite films are made by the casting-evaporation method. However, inferior waterproof and mechanical properties limit their applications in food package industries. Many researches have been conducted to improve the CS film. Incorporating one or several substancesinto CS film have been widespreadly used. Moreover, acetic acid and chitosan-acetate can be removed from traditionally prepared CS film by alkali leaching, resulting in lower film water-solubility. Lavender essential oil (LEO) can be used as sedative, antispasmodic, antiviral and bacteriostat in industries of perfume, aromatherapy and pharmacy. LEO can also be used as a natural spice in drink, ice cream, candy, bakery and chewing gum. In order to improve the physical and mechanical properties of conventional chitosan-based food packaging films, lavender essential oil/chitosan composite films were made with CS by casting-evaporation-alkali leaching method in this study. The films microstructures were characterized by Fourier transform infrared reflectance spectroscopy (FTIR), X-ray diffraction (XRD). The impacts of LEO content on the thickness, mechanical properties, volatiles content, water contact angle, water solubility and swelling property of films were investigated. The results indicated that the partial functional group’s locations of CS matrix were occupied by the LEO ingredients with reduced vibration intensity of covalent bond of CS. Reduced free hydrogen group could form hydrophilic bonds with water, then resulted in the loss of moisture content of films. Moreover, Chitosan-acetate content increased by incorporating LEO. The thicknesses of all films ranged from (20.60±0.34) μm to (23.35±0.65) μm. There was no linear relationship between the film thickness and LEO concentration. Tensile strength (TS) and elongation at

  10. The spacer arm length in cell-penetrating peptides influences chitosan/siRNA nanoparticle delivery for pulmonary inflammation treatment

    Science.gov (United States)

    Jeong, Eun Ju; Choi, Moonhwan; Lee, Jangwook; Rhim, Taiyoun; Lee, Kuen Yong

    2015-11-01

    Although chitosan and its derivatives have been frequently utilized as delivery vehicles for small interfering RNA (siRNA), it is challenging to improve the gene silencing efficiency of chitosan-based nanoparticles. In this study, we hypothesized that controlling the spacer arm length between a cell-penetrating peptide (CPP) and a nanoparticle could be critical to enhancing the cellular uptake as well as the gene silencing efficiency of conventional chitosan/siRNA nanoparticles. A peptide consisting of nine arginine units (R9) was used as a CPP, and the spacer arm length was controlled by varying the number of glycine units between the peptide (R9Gn) and the nanoparticle (n = 0, 4, and 10). Various physicochemical characteristics of R9Gn-chitosan/siRNA nanoparticles were investigated in vitro. Increasing the spacing arm length did not significantly affect the complex formation between R9Gn-chitosan and siRNA. However, R9G10-chitosan was much more effective in delivering genes both in vitro and in vivo compared with non-modified chitosan (without the peptide) and R9-chitosan (without the spacer arm). Chitosan derivatives modified with oligoarginine containing a spacer arm can be considered as potential delivery vehicles for various genes.Although chitosan and its derivatives have been frequently utilized as delivery vehicles for small interfering RNA (siRNA), it is challenging to improve the gene silencing efficiency of chitosan-based nanoparticles. In this study, we hypothesized that controlling the spacer arm length between a cell-penetrating peptide (CPP) and a nanoparticle could be critical to enhancing the cellular uptake as well as the gene silencing efficiency of conventional chitosan/siRNA nanoparticles. A peptide consisting of nine arginine units (R9) was used as a CPP, and the spacer arm length was controlled by varying the number of glycine units between the peptide (R9Gn) and the nanoparticle (n = 0, 4, and 10). Various physicochemical characteristics of

  11. Effects of chitosan solution concentration and incorporation of chitin and glycerol on dense chitosan membrane properties.

    Science.gov (United States)

    Dallan, Paula Rulf Marreco; Moreira, Patrícia da Luz; Petinari, Leandro; Malmonge, Sônia Maria; Beppu, Marisa Masumi; Genari, Selma Candelária; Moraes, Angela Maria

    2007-02-01

    The aim of this work was to perform a systematic study about the effects induced by chitosan solution concentration and by chitin or glycerol incorporation on dense chitosan membranes with potential use as burn dressings. The membrane properties analyzed were total raw material cost, thickness, morphology, swelling ratio, tensile strength, percentage of strain at break, crystallinity, in vitro enzymatic degradation with lysozyme, and in vitro Vero cells adhesion. While the use of the most concentrated chitosan solution (2.5% w/w) increased membrane cost, it also improved the biomaterial mechanical resistance and ductility, as well as reduced membrane degradation when exposed for 2 months to lysozyme. The remaining evaluated properties were not affected by initial chitosan solution concentration. Chitin incorporation, on the other hand, reduced the membranes cost, swelling ratio, mechanical properties, and crystallinity, resulting in thicker biomaterials with irregular surface more easily degradable when exposed to lysozyme. Glycerol incorporation also reduced the membranes cost and crystallinity and increased membranes degradability after exposure to lysozyme. Strong Vero cells adhesion was not observed in any of the tested membrane formulations. The overall results indicate that the majority of the prepared membranes meet the performance requirements of temporary nonbiodegradable burn dressings (e.g. adequate values of mechanical resistance and ductility, low values of in vitro cellular adhesion on their surfaces, low extent of degradation when exposed to lysozyme solution, and high stability in aqueous solutions).

  12. Preparation and Comparison of Chitosan Nanoparticles with Different Degrees of Glutathione Thiolation

    Directory of Open Access Journals (Sweden)

    R Dinarvand

    2011-12-01

    Full Text Available Background: Chitosan has gained considerable attentions as a biocompatible carrier to improve delivery of active agents. Application of this vehicle in the form of nanoparticle could profit advantages of nanotechnology to increase efficacy of active agents. The purpose of this study was to provide detailed information about chitosan-glutathione (Cht-GSHnanoparticles which are gaining popularity because of their high mucoadhesive and extended drug release properties. Methods: Depolymerization of chitosan was carried out using sodium nitrite method.Glutathione was covalently attached to chitosan and the solubility of the resulting conjugates was evaluated. Nanoparticles were prepared by ionic gelation method and then the effect of glutathione immobilization on properties of nanoparticles was investigated. Results: Thiolation efficiency was higher in lower molecular weight chitosan polymers compared to unmodified chitosan nanoparticles. Cht-GSH conjugates of the same molecular weight but with different degrees of thiolation had the same hydrodynamic diameter (995± nm and surface charge (102± mV as unmodified chitosan, but comprised of a denser network structure and lower concentration. Cht-GSH nanoparticles also exhibited greater mucoadhesive strength which was less affected by ionic strength and pH of the environment. Conclusion:Thiolation improves the solubility of chitosan without any significant changes in size and charge of nanoparticles, but affects the nanogel structure.

  13. Maize microarray annotation database

    Directory of Open Access Journals (Sweden)

    Berger Dave K

    2011-10-01

    Full Text Available Abstract Background Microarray technology has matured over the past fifteen years into a cost-effective solution with established data analysis protocols for global gene expression profiling. The Agilent-016047 maize 44 K microarray was custom-designed from EST sequences, but only reporter sequences with EST accession numbers are publicly available. The following information is lacking: (a reporter - gene model match, (b number of reporters per gene model, (c potential for cross hybridization, (d sense/antisense orientation of reporters, (e position of reporter on B73 genome sequence (for eQTL studies, and (f functional annotations of genes represented by reporters. To address this, we developed a strategy to annotate the Agilent-016047 maize microarray, and built a publicly accessible annotation database. Description Genomic annotation of the 42,034 reporters on the Agilent-016047 maize microarray was based on BLASTN results of the 60-mer reporter sequences and their corresponding ESTs against the maize B73 RefGen v2 "Working Gene Set" (WGS predicted transcripts and the genome sequence. The agreement between the EST, WGS transcript and gDNA BLASTN results were used to assign the reporters into six genomic annotation groups. These annotation groups were: (i "annotation by sense gene model" (23,668 reporters, (ii "annotation by antisense gene model" (4,330; (iii "annotation by gDNA" without a WGS transcript hit (1,549; (iv "annotation by EST", in which case the EST from which the reporter was designed, but not the reporter itself, has a WGS transcript hit (3,390; (v "ambiguous annotation" (2,608; and (vi "inconclusive annotation" (6,489. Functional annotations of reporters were obtained by BLASTX and Blast2GO analysis of corresponding WGS transcripts against GenBank. The annotations are available in the Maize Microarray Annotation Database http://MaizeArrayAnnot.bi.up.ac.za/, as well as through a GBrowse annotation file that can be uploaded to

  14. Flocculation Kinetics of Chitosan

    Institute of Scientific and Technical Information of China (English)

    陈亮; 林志艳; 陈东辉

    2003-01-01

    Under the various conditions, the experiments of flocculation of bentonite solution with chitosan were carried out. And the flocculation kinetics was studied by the changes of floc size along with time. The results show that hydraulic gradient G (s-1) plays a key role in growing up of floc size and both of molecular weight and initial turbidity of bentonite solution influence the floc size in steady state and the time needed for steady floc size.

  15. Responses of mesenchymal stem cell to chitosan-coralline composites microstructured using coralline as gas forming agent.

    Science.gov (United States)

    Gravel, Mylène; Gross, Talia; Vago, Razi; Tabrizian, Maryam

    2006-03-01

    Macroporous composites made of coralline:chitosan with new microstructural features were studied for their scaffolding potential in in vitro bone regeneration. By using different ratios of natural coralline powder, as in situ gas forming agent and reinforcing phase, followed by freeze-drying, scaffolds with controlled porosity and pore structure were prepared and cultured with mesenchymal stem cells (MSCs). Their supportive activity of cellular attachment, proliferation and differentiation were assessed through cell morphology studies, DNA content, alkaline phosphatase (ALP) activity and osteocalcin (OC) release. The coralline scaffolds showed by far the highest evaluation of cell number and ALP activity over all the other chitosan-based scaffolds. They were the only material on which the OC protein was released throughout the study. When used as a component of the chitosan composite scaffolds, these coralline's favourable properties seemed to improve the overall performance of the chitosan. Distinct cell morphology and osteoblastic phenotype expression were observed depending on the coralline-to-chitosan ratios composing the scaffolds. The coralline-chitosan composite scaffolds containing high coralline ratios generally showed higher total cell number, ALP activity and OC protein expression comparing to chitosan scaffolds. The results of this study strongly suggest that coralline:chitosan composite, especially those having a high coralline content, may enhance adhesion, proliferation and osteogenic differentiation of MSCs in comparison with pure chitosan. Coralline:chitosan composites could therefore be used as attractive scaffolds for developing new strategies for in vitro tissue engineering.

  16. Absorption enhancing effects of chitosan oligomers on the intestinal absorption of low molecular weight heparin in rats.

    Science.gov (United States)

    Zhang, Hailong; Mi, Jie; Huo, Yayu; Huang, Xiaoyan; Xing, Jianfeng; Yamamoto, Akira; Gao, Yang

    2014-05-15

    Absorption enhancing effects of chitosan oligomers with different type and varying concentration on the intestinal absorption of low molecular weight heparin (LMWH) were examined by an in situ closed loop method in different intestinal sections of rats. Chitosan hexamer with the optimal concentration of 0.5% (w/v) showed the highest absorption enhancing ability both in the small intestine and large intestine. The membrane toxicities of chitosan oligomers were evaluated by morphological observation and determining the biological markers including amount of protein and activity of lactate dehydrogenase (LDH) released from intestinal epithelium cells. There was no obvious change both in levels of protein and LDH and morphology in the intestinal membrane between control and various chitosan oligomers groups, suggesting that chitosan oligomers did not induce any significant membrane damage to the intestinal epithelium. In addition, zeta potentials became less negative and amount of free LMWH gradually decreased when various chitosan oligomers were added to LMWH solution, revealing that electrostatic interaction between positively charged chitosan oligomers and negative LMWH was included in the absorption enhancing mechanism of chitosan oligomers. In conclusion, chitosan oligomers, especially chitosan hexamer, are safe and efficient absorption enhancers and can be used promisingly to improve oral absorption of LMWH.

  17. The Effect of β-Glycerophosphate Crosslinking on Chitosan Cytotoxicity and Properties of Hydrogels for Vaginal Application

    Directory of Open Access Journals (Sweden)

    Emilia Szymaǹska

    2015-11-01

    Full Text Available Mucoadhesive gelling systems based on chitosan and chitosan/β-glycerophosphate (β-GP were developed in order to increase clotrimazole residence time in the vaginal cavity. Ex vivo mucoadhesiveness using porcine vaginal mucosa followed with mechanical, viscoelastic, and swelling properties of prepared hydrogels were evaluated. Drug-free, sterile, unmodified, and β-GP crosslinked chitosan were investigated for the in vitro cytotoxicity in CRL 2616 human vaginal mucosa cells using MTT assay, fluorescent microscopy, and flow cytometry analysis. Chitosan/β-GP hydrogels exhibited pseudoplastic and thixotropic properties. Ionic interaction between β-GP and chitosan improved mechanical properties of hydrogels in terms of hardness, cohesiveness, and compressibility. The hydrogels’ ability to interact with porcine vaginal mucosa (measured as force of detachment and work of adhesion was comparable to those obtained with reference mucoadhesive gel Replens™. Surprisingly, greater mucoadhesive properties were noticed for chitosan/β-GP hydrogels. The cytotoxic effect of unmodified and β-GP crosslinked chitosan was hardly affected by chitosan molecular weight, exhibited mainly through inducing apoptosis, and was found to be significantly lower in the presence of chitosan/β-GP. Furthermore, the higher amount of β-GP was used to crosslink chitosan, the lower cytotoxic effect was observed.

  18. Effects of extraction parameters on physicochemical and functional characteristics of chitosan from Penaeus monodon shell

    Directory of Open Access Journals (Sweden)

    Jubril Olayinka Akolade

    2016-11-01

    Full Text Available Objective: To investigate the effect of extraction parameters with particular interest during the microwave deacetylation process on the characteristics of chitosan produced from Penaeus monodon (P. monodon sourced within the coastal region of Lagos, Nigeria for applications of controlled release systems for pharmaceutical industries. Methods: Chitosan was extracted from shrimp (P. monodon shell and evaluated as a controlled release system for curcumin. Effects of relevant processing parameters on physicochemical and functional characteristics of the extracted chitosan were assessed. The crude chitosan was purified and used to prepare controlled release formulations for curcumin via ionic gelation with tripolyphosphate. Results: Data from the study showed that increasing time and temperature during deproteinization significantly improved the removal of protein bound to the shell matrix. Also, the ratio of the weight of the deproteinized sample to the volume of HCl used for demineralization influenced the process. During microwave-assisted production of chitosan from chitin, increase in the concentration of the deacetylating medium significantly increased solubility, viscosity and degree of deacetylation, whereas increasing temperature and time during deacetylation of chitin degraded the biopolymer to give low molecular weight chitosan. Optimized extraction and purification process yielded absolutely soluble medium to low molecular weight chitosan. The encapsulation efficiency, loading capacity, percentage yield, release efficiencies in simulated gastric and intestinal fluids of curcumin loaded in the formulations of chitosan from P. monodon were compared favorably to encapsulation and release characteristics of the encapsulated curcumin in commercially available chitosan used as the reference. Conclusions: Valorization of shrimp waste into pharmaceutically graded medium molecular weight chitosan was achieved. The chitosan obtained can be used as

  19. Effects of extraction parameters on physicochemical and functional characteristics of chitosan from Penaeus monodon shell

    Institute of Scientific and Technical Information of China (English)

    Jubril Olayinka Akolade; Hussein Oyelola Bukoye Oloyede; Paul Chidozie Onyenekwe

    2016-01-01

    ABSTRACT Objective: To investigate the effect of extraction parameters with particular interest during the microwave deacetylation process on the characteristics of chitosan produced fromPenaeus monodon (P. monodon) sourced within the coastal region of Lagos, Nigeria for applications of controlled release systems for pharmaceutical industries. Methods: Chitosan was extracted from shrimp (P. monodon) shell and evaluated as a controlled release system for curcumin. Effects of relevant processing parameters on physicochemical and functional characteristics of the extracted chitosan were assessed. The crude chitosan was purified and used to prepare controlled release formulations for curcumin via ionic gelation with tripolyphosphate. Results:Data from the study showed that increasing time and temperature during deproteinization significantly improved the removal of protein bound to the shell matrix. Also, the ratio of the weight of the deproteinized sample to the volume ofHCl used for demineralization influenced the process. During microwave-assisted production of chitosan from chitin, increase in the concentration of the deacetylating medium significantly increased solubility, viscosity and degree of deacetylation, whereas increasing temperature and time during deacetylation of chitin degraded the biopolymer to give low molecular weight chitosan. Optimized extraction and purification process yielded absolutely soluble medium to low molecular weight chitosan. The encapsulation efficiency, loading capacity, percentage yield, release efficiencies in simulated gastric and intestinal fluids of curcumin loaded in the formulations of chitosan fromP. monodon were compared favorably to encapsulation and release characteristics of the encapsulated curcumin in commercially available chitosan used as the reference. Conclusions:Valorization of shrimp waste into pharmaceutically graded medium molecular weight chitosan was achieved. The chitosan obtained can be used as a controlled

  20. Conjugating influenza a (H1N1) antigen to n-trimethylaminoethylmethacrylate chitosan nanoparticles improves the immunogenicity of the antigen after nasal administration.

    Science.gov (United States)

    Liu, Qingfeng; Zheng, Xiaoyao; Zhang, Chi; Shao, Xiayan; Zhang, Xi; Zhang, Qizhi; Jiang, Xinguo

    2015-11-01

    As one of the most serious infectious respiratory diseases, influenza A (H1N1) is a great threat to human health, and it has created an urgent demand for effective vaccines. Nasal immunization can induce both systemic and mucosal immune responses against viruses, and it can serve as an ideal route for vaccination. However, the low immunogenicity of antigens on nasal mucosa is a high barrier for the development of nasal vaccines. In this study, we covalently conjugated an influenza A (H1N1) antigen to the surface of N-trimethylaminoethylmethacrylate chitosan (TMC) nanoparticles (H1N1-TMC/NP) through thioester bonds to increase the immunogenicity of the antigen after nasal administration. SDS-PAGE revealed that most of the antigen was conjugated on TMC nanoparticles, and an in vitro biological activity assay confirmed the stability of the antigen after conjugation. After three nasal immunizations, the H1N1-TMC/NP induced significantly higher levels of serum IgG and mucosal sIgA compared with free antigen. A hemagglutination inhibition assay showed that H1N1-TMC/NP induced much more protective antibodies than antigen-encapsulated nanoparticles or alum-precipitated antigen (I.M.). In the mechanistic study, H1N1-TMC/NP was shown to stimulate macrophages to produce IL-1β and IL-6 and to stimulate spleen lymphocytes to produce IL-2 and IFN-γ. These results indicated that H1N1-TMC/NP may be an effective vaccine against influenza A (H1N1) viruses for use in nasal immunization.

  1. A Pseudomonas strain isolated from date-palm rhizospheres improves root growth and promotes root formation in maize exposed to salt and aluminum stress.

    Science.gov (United States)

    Zerrouk, Izzeddine Zakarya; Benchabane, Messaoud; Khelifi, Lakhdar; Yokawa, Ken; Ludwig-Müller, Jutta; Baluska, Frantisek

    2016-02-01

    The aim of this study was to evaluate the effectiveness of Pseudomonas fluorescens 002 (P.f.002.), isolated from the rhizosphere of date palms from the Ghardaia region in the Algerian Sahara, to promote root growth of two varieties of maize under conditions of salt and aluminum stress. Primary roots of 5-day-old seedlings were inoculated with P.f.002., and seedlings were then grown under both control and stressed conditions. Primary, lateral, and seminal root lengths and numbers, as well as root dry mass, were evaluated. P.f.002 increased all parameters measured under both salt and aluminum stress. Hence, the use of P.f.002 may represent an important biotechnological approach to decrease the impact of salinity and acidity in crops.

  2. Physiological, Biochemical and Molecular Characterization of Barley (Hordeum vulgare L.) and Maize (Zea mays L.) for Improving Manganese Efficiency

    DEFF Research Database (Denmark)

    Long, Lizhi

    and the interaction between latent Mn deficiency and light stress in maize plants. The obtained results showed that latent Mn deficiency decreased the utilization of photosynthetically active light, inhibited the ability to perform photosynthetic state transitions and the response of net photosynthetic CO2......Manganese (Mn) deficiency is a nutritional problem, causing significant reductions in crop yields and in severe cases resulting in complete loss of crops during winter time. Different plant species and genotypes within the same species vary in their tolerance with respect to growth in soils...... with low Mn availability, a phenomenon referred to as Mn efficiency. Iron-regulated transporter 1 (IRT1), known to be correlated with Mn uptake capacity and Mn efficiency in barley, was characterized using barley RNAi lines. The obtained results showed that HvIRT1 was involved in uptake and root...

  3. Hexanoyl Chitosan-based Gel Electrolyte for Lithium-ion Cell

    Institute of Scientific and Technical Information of China (English)

    Tan Winie; A.K. Arof

    2005-01-01

    @@ 1Introduction Chitosan is soluble in dilute acid solutions as a result of salt formation by the amino groups with various inorganic and organic acids[1,2]. Due to the reactivity of water and other protic solvents such as methanol and acetic acid with the electrode material in the lithiumbased electrochemicaldevices[3], the insolubility of chitosan in aprotic solvents is inadequate to meet the requirements to be used as the electrolyte materials. In order to improve its solubility in aprotic solvents,acyl modification of chitosan was carried out in the present study.Hexanoyl-chitosan (Fig. 1) that exhibited solubility in THF was prepared by reacting the chitosan with hexanoyl chloride in a mixture of pyridine and THF[4].

  4. Synthesis and characterization of chitosan based dye containing quaternary ammonium group.

    Science.gov (United States)

    Tang, Ruilin; Zhang, Ying; Zhang, Yang; Yu, Zhiming

    2016-03-30

    A new antimicrobial biopolymer dye was synthesized by reaction of quaternary ammonium salt of chitosan and reactive red x-3b. And quaternary ammonium salt of chitosan was produced by grafting glycidyltrimethylammonium chloride on chitosan. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), solubility test and antimicrobial test. Results show that the antimicrobial biopolymer dye was combined by N(+)(CH3)3 of quaternary ammonium salt of chitosan and sulfonic group of reactive red x-3b. Water solubility of chitosan biopolymer dye was increased as well as pH value. In addition, antibacterial property of new synthesized dye was excellent, whose antibacterial rates of Staphylococcus and Escherichia coli were both bigger than 99%. These results may provide new perspectives on improving the decorative properties and antimicrobial properties in wood industry.

  5. Effects of heat treatment on chitosan nanocomposite film reinforced with nanocrystalline cellulose and tannic acid.

    Science.gov (United States)

    Rubentheren, V; Ward, Thomas A; Chee, Ching Yern; Nair, Praveena; Salami, Erfan; Fearday, Christopher

    2016-04-20

    This article presents an analysis of the influence of heat treatment on chitosan nanocomposite film. A series of samples comprising: pure chitosan film, chitosan film embedded with nanocrystalline cellulose (NCC), chitosan film crosslinked with tannic acid and chitosan film with a blend of NCC and tannic acid were heat treated using a convection oven. Fourier-transform-infrared spectroscopy (FTIR) and X-ray diffraction test (XRD) shows the changes in chemical interaction of the heat treated films. The heat treated films show significant improvements in moisture absorption. Tensile strength and Young's Modulus were increased up to 7MPa and 259MPa, respectively when the samples were subjected to heat treatment. For the NCC particles, a transmission electron microscope (TEM) was used to inspect the structural properties of cellulose particle in suspension form.

  6. Non-woven nanofiber chitosan/peo membranes obtained by electrospinning

    Directory of Open Access Journals (Sweden)

    M. T. M. Bizarria

    2014-03-01

    Full Text Available The present work focused on the preparation and morphological characterization of chitosan-based nanofiber membranes, aiming at applications in medical and pharmacological areas. Membranes with nanofiber diameters ranging from 50 - 300 nm were prepared from polymer solutions through the electrospinning process. To stabilize the process, it was necessary to use poly(ethylene oxide (PEO, which is a biocompatible synthetic polymer. Pure chitosan solutions, as well as chitosan and PEO solution blends, were characterized by their rheological behavior, conductivity, and surface tension measurements. The electrospun fiber thermal characteristics and crystalline structures were investigated through thermogravimetric analysis (TG and differential scanning calorimetry (DSC. Scanning electron microscopy images (SEM were used for the morphological evaluations of the membranes. The addition of PEO to the chitosan solutions improved their electrical conductivity, surface tension and viscosity, greatly favoring the electrospinning process. Thus, membranes with 80% chitosan could be electrospun.

  7. Quality protein maize: QPM

    Directory of Open Access Journals (Sweden)

    Ignjatović-Micić Dragana

    2008-01-01

    Full Text Available Quality protein maize (QPM contains the opaque-2 gene along with numerous modifiers for kernel hardness. Therefore, QPM is maize with high nutritive value of endosperm protein, with substantially higher content of two essential amino acids - lysine and tryptophan, and with good agronomical performances. Although QPM was developed primarily for utilization in the regions where, because of poverty, maize is the main staple food, it has many advantages for production and consumption in other parts of the world, too. QPM can be used for production of conventional and new animal feed, as well as for human nurture. As the rate of animal weight gain is doubled with QPM and portion viability is better, a part of normal maize production could be available for other purposes, such as, for example, ethanol production. Thus, breeding QPM is set as a challenge to produce high quality protein maize with high yield and other important agronomical traits, especially with today's food and feed demands and significance of energy crisis.

  8. Influence of Process Control Agent on Characterization and Structure of Micron Chitosan Powders Prepared by Ball Milling Method

    Directory of Open Access Journals (Sweden)

    ZHANG Chuan-jie

    2016-12-01

    Full Text Available With ethyl alcohol or distilled water as process control agent (PCA, micron chitosan powder was prepared by ball milling method. The yield rate, particle size distribution, micro morphology, viscosity average molecular mass, chemical and crystal structures, and thermal properties of these different micron chitosan powders were measured. The results indicate that the yield rate of micron chitosan powders prepared with ethyl alcohol as PCA increases significantly, and improves to 94.7% from 25% while the amount of ethyl alcohol is 0.75mL/g. The particle size distribution of micron chitosan powder prepared with ethyl alcohol as PCA is concentrated, while the D50 and D90 in size are 824nm and 1629nm respectively. Chitosan do not react with ethyl alcohol used as PCA, but the viscosity average molecular mass of prepared micron chitosan powder decreases by 23%, the crystal structures are destroyed slightly, and its thermal stability is slightly weakened.

  9. Influence of Sulfonated-Kaolin On Cationic Exchange Capacity Swelling Degree and Morphology of Chitosan/Kaolin Composites

    Directory of Open Access Journals (Sweden)

    Ozi Adi Saputra

    2016-06-01

    Full Text Available Preparation of sulfonated-kaolin (sKao has been conducted and used as filler on chitosan matrix via solution casting method, namely chitosan/sKao (Cs/sKao. Swelling degree, cationic exchange capacity and thermal stability were evaluated to determine chitosan/sKao membranes performance as proton exchange membrane in fuel cell. Functional group analysis of chitosan, sKao and synthesized products were studied using Fourier Transform Infra-Red (FTIR spectroscopy. In this study, swelling degree and swelling area of Cs/sKao are also studied to determine of membrane ability to swelling which compare to unmodified chitosan/kaolin (Cs/Kao. The presence of sKao in chitosan matrix was able to improve cationic exchange capacity (CEC which proved by morphological study of membrane surface after CEC test. Moreover, Thermal stability of Cs/sKao showed the membrane has meet requirement for PEM application.

  10. Dietary chitosan nanoparticles protect crayfish Procambarus clarkii against white spot syndrome virus (WSSV) infection.

    Science.gov (United States)

    Sun, Baozhen; Quan, Haizhi; Zhu, Fei

    2016-07-01

    Chitosan nanoparticles have exhibited potential antibacterial activity or anticancer activity as their unique character. In this study, we investigated the effect of chitosan nanoparticles protect crayfish Procambarus clarkii against WSSV. Chitosan (from crab shell) nanoparticles were prepared by ultrafine milling. The physicochemical properties of the nanoparticles were determined by particle size measure, zeta potential analysis and scanning electron microscope observation. The total hemocyte count (THC), phenoloxidase (PO) and superoxide dismutase (SOD) activity were measured at days 1, 4, 9 and 12, and the survival rate was also recorded after WSSV challenge. The results showed that chitosan nanoparticles could enhance the survival rate of WSSV-challenged crayfish. And crayfish fed diets supplemented with 10 mg/g chitosan nanoparticles (65% mortality) showed a significantly higher survival rate when compared to the control group (100% mortality). The analysis of immunological parameters revealed that 10 mg/g chitosan nanoparticles showed significantly higher level of prophenoloxidase (proPO), superoxide dismutase (SOD) and total hemocyte count (THC) when compared to the control group. It was found that chitosan nanoparticles could inhibit WSSV replication in crayfish. Our results demonstrated that dietary chitosan nanoparticles effectively improve innate immunity and survival of P. clarkii challenged with WSSV.

  11. Development of drug-loaded chitosan-vanillin nanoparticles and its cytotoxicity against HT-29 cells.

    Science.gov (United States)

    Li, Pu-Wang; Wang, Guang; Yang, Zi-Ming; Duan, Wei; Peng, Zheng; Kong, Ling-Xue; Wang, Qing-Huang

    2016-01-01

    Chitosan as a natural polysaccharide derived from chitin of arthropods like shrimp and crab, attracts much interest due to its inherent properties, especially for application in biomedical materials. Presently, biodegradable and biocompatible chitosan nanoparticles are attractive for drug delivery. However, some physicochemical characteristics of chitosan nanoparticles still need to be further improved in practice. In this work, chitosan nanoparticles were produced by crosslinking chitosan with 3-methoxy-4-hydroxybenzaldehyde (vanillin) through a Schiff reaction. Chitosan nanoparticles were 200-250 nm in diameter with smooth surface and were negatively charged with a zeta potential of - 17.4 mV in neutral solution. Efficient drug loading and drug encapsulation were achieved using 5-fluorouracil as a model of hydrophilic drug. Drug release from the nanoparticles was constant and controllable. The in vitro cytotoxicity against HT-29 cells and cellular uptake of the chitosan nanoparticles were evaluated by methyl thiazolyl tetrazolium method, confocal laser scanning microscope and flow cytometer, respectively. The results indicate that the chitosan nanoparticles crosslinked with vanillin are a promising vehicle for the delivery of anticancer drugs.

  12. Effect of radiation-degraded chitosan on growth promotion of flower plant in tissue culture

    Energy Technology Data Exchange (ETDEWEB)

    Luan, Le Quang; Ha, Vo Thi Thu; Hai, Le; Hien, Nguyen Quoc [Vietnam Atomic Energy Commission, Nuclear Research Institute, Dalat (Viet Nam); Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    Radiation is a useful tool for degradation of polysaccharides, such as starch, carrageenan, alginate and chitin/chitosan. The viscosity molecular weight (Mw) of chitosan with 80% degree of deacetylation was reduced to 1.5 x 10{sup 5} by irradiation of 50kGy in solid phase. The solution of 10% of chitosan with Mw ca. 15 x 10{sup 5} was then irradiated at doses ranging 10-250kGy for further degradation and the products were supplemented into cultural media for testing of plant growth promotion effect. The results indicated that irradiated chitosan showed a strong growth-promotion effect on the increase of the length of shoot, the length of root and fresh biomass for flower plants namely Limonium latifolium, Eustoma grandiflorum and Chrysanthemum morifolium in tissue culture. The growth-promotion effect was obtained by the treatments with 50ppm of chitosan irradiated at the doses of 75-100kGy in 10% solution. The suitable concentrations of chitosan irradiated at 100kGy are ca. 100ppm for C. morifolium, 30ppm for E. grandiflorum and 40ppm for L. latifolium. In addition, our study also indicated that the survival ratio of transferred flower plantlets treated with irradiated chitosan was improved after acclimatizing for 30 days in the greenhouse. Accordingly, it is concluded that degraded chitosan obtained by radiation degradation technique is effective as a plant growth promoter as well as irradiated alginate. (author)

  13. Functionalization of Titanium with Chitosan via Silanation: Evaluation of Biological and Mechanical Performances

    Science.gov (United States)

    Renoud, Pauline; Toury, Bérangère; Benayoun, Stéphane; Attik, Ghania; Grosgogeat, Brigitte

    2012-01-01

    Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation. PMID:22859940

  14. Functionalization of titanium with chitosan via silanation: evaluation of biological and mechanical performances.

    Science.gov (United States)

    Renoud, Pauline; Toury, Bérangère; Benayoun, Stéphane; Attik, Ghania; Grosgogeat, Brigitte

    2012-01-01

    Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation.

  15. Development of Thermosensitive Hydrogels of Chitosan, Sodium and Magnesium Glycerophosphate for Bone Regeneration Applications

    Directory of Open Access Journals (Sweden)

    Jana Lisková

    2015-04-01

    Full Text Available Thermosensitive injectable hydrogels based on chitosan neutralized with sodium beta-glycerophosphate (Na-β-GP have been studied as biomaterials for drug delivery and tissue regeneration. Magnesium (Mg has been reported to stimulate adhesion and proliferation of bone forming cells. With the aim of improving the suitability of the aforementioned chitosan hydrogels as materials for bone regeneration, Mg was incorporated by partial substitution of Na-β-GP with magnesium glycerophosphate (Mg-GP. Chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were also loaded with the enzyme alkaline phosphatase (ALP which induces hydrogel mineralization. Hydrogels were characterized physicochemically with respect to mineralizability and gelation kinetics, and biologically with respect to cytocompatibility and cell adhesion. Substitution of Na-β-GP with Mg-GP did not negatively influence mineralizability. Cell biological testing showed that both chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were cytocompatible towards MG63 osteoblast-like cells. Hence, chitosan/Na-β-GP/Mg-GP hydrogels can be used as an alternative to chitosan/Na-β-GP hydrogels for bone regeneration applications. However the incorporation of Mg in the hydrogels during hydrogel formation did not bring any appreciable physicochemical or biological benefit.

  16. Functionalization of titanium with chitosan via silanation: evaluation of biological and mechanical performances.

    Directory of Open Access Journals (Sweden)

    Pauline Renoud

    Full Text Available Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation.

  17. Chitosan-aprotinin coated liposomes for oral peptide delivery: Development, characterisation and in vivo evaluation.

    Science.gov (United States)

    Werle, Martin; Takeuchi, Hirofumi

    2009-03-31

    In order to improve the systemic uptake of therapeutic peptides/proteins after oral administration, the polymer-protease inhibitor conjugate chitosan-aprotinin was synthesised and polyelectrolyte complexes between negatively charged multilamellar vesicles (MLV) and positively charged chitosan-aprotinin conjugate were prepared. It could be demonstrated that chitosan-aprotinin was capable of significantly inhibiting Trypsin in vitro in concentrations of 0.05% and 0.1%, whereas no inhibition was observed in the presence of 0.1% chitosan. The size range of the prepared MLV was between 3 and 4.5microm and the initially negative zeta potential (ca. -90mV) of the core liposomes switched to a positive value after polymer coating (ca. +40mV). Confocal laser microscopy studies showed comparable mucoadhesive properties of chitosan-aprotinin coated MLV and chitosan coated MLV. In comparison to calcitonin in solution, the area above the blood calcium concentration-time curve (AAC) after oral administration of calcitonin loaded chitosan coated MLV to rats increased around 11-fold, and around 15-fold in the case of calcitonin loaded chitosan-aprotinin coated MLV. Data gained in the current study are believed to contribute to the development of novel polymer-protease inhibitor based delivery systems.

  18. Chitosan and chitosan-based particle systems containing a bioactive fish peptide in the abatement of Escherichia coli related infections in the small intestine

    DEFF Research Database (Denmark)

    Bechstein, Stefanie

    . Additionally, it should have preventive effects and should also be able to eradicate an already established infection or biofilm. Hence, chitosan appears to be a good choice. Chitosan is a natural polymer that is commonly found in crustacean shells and exhibits antibacterial activity. The effect is supposably...... probably due to a high particle stability, suggesting that further modifications and improvements of the systems have to be undertaken. Coated particles were shown to interact with the bacteria sufficiently and the CS coat was able to initiate bacterial aggregation. Furthermore, chitosan and CS...

  19. [Impacts of high temperature on maize production and adaptation measures in Northeast China].

    Science.gov (United States)

    Yin, Xiao-gang; Wang, Meng; Kong, Qing-xin; Wang, Zhan-biao; Zhang, Hai-lin; Chu, Qing-quan; Wen, Xin-ya; Chen, Fu

    2015-01-01

    Heat stress is one of the major agro-meteorological hazards that affect maize production significantly in the farming region of Northeast China (NFR). This study analyzed the temporal and spatial changes of the accumulated temperature above 30 °C (AT) and the accumulated days with the maximum temperature above 30 °C (AD) in different maize growing phases under global warming. It further evaluated the impacts of extreme heat on maize yield in different regions, and put forward some adaptation measures to cope with heat stress for maize production in NFR. The results showed that during 1961 to 2010, the temperature in the maize growing season increased significantly. The maximum temperature in flowering phase was much larger than that in the other growing phases. Temperature increased at rates of 0. 16, 0. 14, 0.06 and 0.23 °C every ten years in the whole maize growing season, vegetative growth phase (from sowing to 11 days before flowering), flowering phase, and late growth phase (from 11 days after flowering to maturity), respectively. The AT in the whole maize growing season increased in NFR during the last 50 years with the highest in the southwest part of NFR, and that in the vegetative growth phase increased faster than in the other two phases. The AD in the whole maize growing season increased during the last 50 years with the highest in the southwest part of NFR, and that in the late growth phase increased faster than in the other two phases. Heat stress negatively affected maize yield during the maize growing season, particularly in the vegetative growth phase. The heat stress in Songliao Plain was much higher in comparison to the other regions. The adaptation measures of maize production to heat stress in NFR included optimizing crop structure, cultivating high temperature resistant maize varieties, improving maize production management and developing the maize production system that could cope with disasters.

  20. Radiation-induced and sonochemical degradation of chitosan as a way to increase its fat-binding capacity

    Science.gov (United States)

    Czechowska-Biskup, R.; Rokita, B.; Ulanski, P.; Rosiak, J. M.

    2005-07-01

    Three physical methods of chitosan degradation: irradiation in dry state, irradiation in aqueous solution and sonication in aqueous solution were tested and compared in the terms of yields and side effects. The influence of average molecular weight of chitosan in its fat-binding ability in vitro has been studied by using a biopharmaceutical model of digestive tract. It was found that reduction in molecular weight leads to a significant increase in the amount of fat bound by 1 g of chitosan. Thus, radiation- or sonochemical treatment may be useful in improving fat-binding properties of chitosan as an active component of dietary food additives.

  1. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    OpenAIRE

    2007-01-01

    Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a...

  2. Genetic Architecture of Domestication-Related Traits in Maize.

    Science.gov (United States)

    Xue, Shang; Bradbury, Peter J; Casstevens, Terry; Holland, James B

    2016-09-01

    Strong directional selection occurred during the domestication of maize from its wild ancestor teosinte, reducing its genetic diversity, particularly at genes controlling domestication-related traits. Nevertheless, variability for some domestication-related traits is maintained in maize. The genetic basis of this could be sequence variation at the same key genes controlling maize-teosinte differentiation (due to lack of fixation or arising as new mutations after domestication), distinct loci with large effects, or polygenic background variation. Previous studies permit annotation of maize genome regions associated with the major differences between maize and teosinte or that exhibit population genetic signals of selection during either domestication or postdomestication improvement. Genome-wide association studies and genetic variance partitioning analyses were performed in two diverse maize inbred line panels to compare the phenotypic effects and variances of sequence polymorphisms in regions involved in domestication and improvement to the rest of the genome. Additive polygenic models explained most of the genotypic variation for domestication-related traits; no large-effect loci were detected for any trait. Most trait variance was associated with background genomic regions lacking previous evidence for involvement in domestication. Improvement sweep regions were associated with more trait variation than expected based on the proportion of the genome they represent. Selection during domestication eliminated large-effect genetic variants that would revert maize toward a teosinte type. Small-effect polygenic variants (enriched in the improvement sweep regions of the genome) are responsible for most of the standing variation for domestication-related traits in maize.

  3. Chitosan grafted monomethyl fumaric acid as a potential food preservative.

    Science.gov (United States)

    Khan, Imran; Ullah, Shafi; Oh, Deog-Hwan

    2016-11-01

    The present study aims at in vitro antibacterial and antioxidant activity evaluation of chitosan modified with monomethyl fumaric acid (MFA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as mediator. Three different kinds of chitosan derivatives Ch-Ds-1,Ch-Ds-2 and Ch-Ds-3 were synthesized by feeding different concentration of MFA. The chemical structures of resulting materials were characterized by (1)H NMR, (13)C NMR, HR-XRD, FT-IR and TNBS assay. The results showed that Ch-Ds-1, Ch-Ds-2 and Ch-Ds-3 were successfully synthesized. The % amino groups of chitosan modified by MFA were evaluated by TNBS assay and ranging from 1.82±0.05% to 7.88±0.04%. All the chitosan derivatives are readily soluble in water and swelled by dimethyl sulfoxide (DMSO), toluene and dimethyl formamide (DMF). The antioxidant activity for all the chitosan derivatives have been significantly improved (Pfood preservative and packaging material for long time food safety and security.

  4. Covalently Bonded Chitosan on Graphene Oxide via Redox Reaction

    Directory of Open Access Journals (Sweden)

    Víctor M. Castaño

    2013-03-01

    Full Text Available Carbon nanostructures have played an important role in creating a new field of materials based on carbon. Chemical modification of carbon nanostructures through grafting has been a successful step to improve dispersion and compatibility in solvents, with biomolecules and polymers to form nanocomposites. In this sense carbohydrates such as chitosan are extremely valuable because their functional groups play an important role in diversifying the applications of carbon nanomaterials. This paper reports the covalent attachment of chitosan onto graphene oxide, taking advantage of this carbohydrate at the nanometric level. Grafting is an innovative route to modify properties of graphene, a two-dimensional nanometric arrangement, which is one of the most novel and promising nanostructures. Chitosan grafting was achieved by redox reaction using different temperature conditions that impact on the morphology and features of graphene oxide sheets. Transmission Electron Microscopy, Fourier Transform Infrared, Raman and Energy Dispersive spectroscopies were used to study the surface of chitosan-grafted-graphene oxide. Results show a successful modification indicated by the functional groups found in the grafted material. Dispersions of chitosan-grafted-graphene oxide samples in water and hexane revealed different behavior due to the chemical groups attached to the graphene oxide sheet.

  5. QTL Mapping of Low-Temperature Germination Ability in the Maize IBM Syn4 RIL Population

    OpenAIRE

    Shuaidong Hu; Thomas Lübberstedt; Guangwu Zhao; Michael Lee

    2016-01-01

    Low temperature is the primary factor to affect maize sowing in early spring. It is, therefore, vital for maize breeding programs to improve tolerance to low temperatures at seed germination stage. However, little is known about maize QTL involved in low-temperature germination ability. 243 lines of the intermated B73×Mo17 (IBM) Syn4 recombinant inbred line (RIL) population was used for QTL analysis of low-temperature germination ability. There were significant differences in germination-rela...

  6. From many, one: genetic control of prolificacy during maize domestication.

    Directory of Open Access Journals (Sweden)

    David M Wills

    2013-06-01

    Full Text Available A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips. Maize has much shorter lateral branches that are tipped by a single large ear with no additional ears at the branch nodes. To investigate the genetic basis of this difference in prolificacy (the number of ears on a plant, we performed a genome-wide QTL scan. A large effect QTL for prolificacy (prol1.1 was detected on the short arm of chromosome 1 in a location that has previously been shown to influence multiple domestication traits. We fine-mapped prol1.1 to a 2.7 kb "causative region" upstream of the grassy tillers1 (gt1 gene, which encodes a homeodomain leucine zipper transcription factor. Tissue in situ hybridizations reveal that the maize allele of prol1.1 is associated with up-regulation of gt1 expression in the nodal plexus. Given that maize does not initiate secondary ear buds, the expression of gt1 in the nodal plexus in maize may suppress their initiation. Population genetic analyses indicate positive selection on the maize allele of prol1.1, causing a partial sweep that fixed the maize allele throughout most of domesticated maize. This work shows how a subtle cis-regulatory change in tissue specific gene expression altered plant architecture in a way that improved the harvestability of maize.

  7. Pluronic F127/chitosan blend microspheres for mucoadhesive drug delivery

    Science.gov (United States)

    Gu, W. Z.; Hu, X. F.

    2017-01-01

    Pluronic F127/chitosan blend microspheres were prepared via emulsification and cross-linking process using glutaraldehyde as a cross-linker. Compared with chitosan microspheres fabricated under the same experimental conditions, blend microspheres exhibited better physical stability and higher swelling capacity. Puerarin, a traditional Chinese medicine, was incorporated into microparticlesas the model drug. The in vitro release of puerarin from blend microspheres was reduced because of the improved compatibility of the drug with the matrices. According to the results from in vitro adhesion experiments, mucoadhesive behavior of blend microspheres on a mucosa-like surface was similar to that of chitosan microspheres, despite their good ability of anti-protein absorption in solution.

  8. Adsorption of hexavalent chromium by graphite–chitosan binary composite

    Indian Academy of Sciences (India)

    RAJENDRA S DONGRE

    2016-06-01

    Graphite chitosan binary (GCB) composite was prepared for hexavalent chromium adsorption from studied water. GCB was characterized by TGA, FTIR, SEM and X-ray diffraction techniques.Wide porous sorptive surface of 3.89 m$^2$ g$^{−1}$ and absorptive functionalities of GCB was due to 20% (w/w) graphite support on chitosan evidenced from FTIR and SEM that impart maximum adsorption at pH 4, agitation with 200 rpm for 180 min. Adsorption studies revealed intraparticle diffusion models and best-fitted kinetics was pseudo 2nd order one. A wellfitted Langmuir isotherm model suggested monolayer adsorption with an adsorption capacity ($q_m$) of 105.6 mg g$^{−1}$ and $R^2 = 0.945$. Sorption mechanisms based on metal ionic interactions, intrusion/diffusion and chemisorptions onto composite. This graphite chitosan binary composite improve sorbent capacity for Cr(VI).

  9. Synthesis and Functions of Jasmonates in Maize

    Directory of Open Access Journals (Sweden)

    Eli J. Borrego

    2016-11-01

    Full Text Available Of the over 600 oxylipins present in all plants, the phytohormone jasmonic acid (JA remains the best understood in terms of its biosynthesis, function and signaling. Much like their eicosanoid analogues in mammalian system, evidence is growing for the role of the other oxylipins in diverse physiological processes. JA serves as the model plant oxylipin species and regulates defense and development. For several decades, the biology of JA has been characterized in a few dicot species, yet the function of JA in monocots has only recently begun to be elucidated. In this work, the synthesis and function of JA in maize is presented from the perspective of oxylipin biology. The maize genes responsible for catalyzing the reactions in the JA biosynthesis are clarified and described. Recent studies into the function of JA in maize defense against insect herbivory, pathogens and its role in growth and development are highlighted. Additionally, a list of JA-responsive genes is presented for use as biological markers for improving future investigations into JA signaling in maize.

  10. Preparation and Characterization of Acylated Chitosan

    Institute of Scientific and Technical Information of China (English)

    LI Ming-chun; LIU Chao; XIN Mei-hua; ZHAO Huang; WANG Min; FENG Zhen; SUN Xiao-li

    2005-01-01

    Fully acylated chitosan and N, N-diacyl chitosan were prepared. The products were characterized by elemental analysis, FTIR and 1H NMR. The experimental results indicate that the average degree of acylation depends on the volume ratio of pyridine to chloroform in the reaction medium, the chain length of the acylation agent used, and the molecular weight of chitosan raw materials. The XRD measurements were carried out for pure chitosan, fully acylated chitosan and N, N-diacyl chitosan to verify the crystallinity change caused by the acylation.

  11. Choosing a genome browser for a Model Organism Database: surveying the maize community.

    Science.gov (United States)

    Sen, Taner Z; Harper, Lisa C; Schaeffer, Mary L; Andorf, Carson M; Seigfried, Trent E; Campbell, Darwin A; Lawrence, Carolyn J

    2010-01-01

    As the B73 maize genome sequencing project neared completion, MaizeGDB began to integrate a graphical genome browser with its existing web interface and database. To ensure that maize researchers would optimally benefit from the potential addition of a genome browser to the existing MaizeGDB resource, personnel at MaizeGDB surveyed researchers' needs. Collected data indicate that existing genome browsers for maize were inadequate and suggest implementation of a browser with quick interface and intuitive tools would meet most researchers' needs. Here, we document the survey's outcomes, review functionalities of available genome browser software platforms and offer our rationale for choosing the GBrowse software suite for MaizeGDB. Because the genome as represented within the MaizeGDB Genome Browser is tied to detailed phenotypic data, molecular marker information, available stocks, etc., the MaizeGDB Genome Browser represents a novel mechanism by which the researchers can leverage maize sequence information toward crop improvement directly. Database URL: http://gbrowse.maizegdb.org/

  12. The potential of chitosan combined with chicken shank collagen as scaffold on bone defect regeneration process in Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    Fitria Rahmitasari

    2016-12-01

    Full Text Available Background: In the field of dentistry, alveolar bone damage can be caused by periodontal disease, traumatic injury due to tooth extraction, cyst enucleation, and tumor surgery. One of the ways to regenerate the bone defect is using graft scaffold. Thus, combination of chitosan and collagen can stimulate osteogenesis. Purpose: The aim of this study was to examine the potential of chitosan combined with chicken shank collagen on bone defect regeneration process. Method: Twelve Rattus norvegicus were prepared as animal models in this research. A bone defect was intentionally created at both of the right and left femoral bones of the models. Next, 24 samples were divided into four groups, namely Group 1 using chitosan – collagen scaffold (50:50, Group 2 using chitosan collagen-scaffold (80:20, Group 3 using chitosan scaffold only, and Control Group using 3% CMC-Na. On 14th day, those animals were sacrificed, and histopathological anatomy examination was conducted to observe osteoclast cells. In addition, immunohistochemistry examination was also performed to observe RANKL expressions. Result: There was a significant difference in RANKL expressions among the groups, except between Group 3 using chitosan scaffold only and control group (p value > 0.05. The highest expression of RANKL was found in Group 1 with chitosan – collagen scaffold (50:50, followed by Group 2 with chitosan-collagen scaffold (80:20. Moreover, there was also a significant difference in osteoclast generation, except between Group 1 using chitosan – collagen scaffold (50:50 and Group 2 using chitosan-collagen scaffold (80:20, p value 0.05. Less osteoclast was found in the groups using chitosan – collagen scaffold (Group 1 and Group 2. Conclusion: Combination of chitosan and chicken shank collagen scaffold can improve regeneration process of bone defect in Rattus novergicus animals through increasing of RANKL expressions, and decreasing of osteoclast.

  13. Chitosan as a Modifying Component of Artificial Scaffold for Human Skin Tissue Engineering.

    Science.gov (United States)

    Romanova, O A; Grigor'ev, T E; Goncharov, M E; Rudyak, S G; Solov'yova, E V; Krasheninnikov, S T; Saprykin, V P; Sytina, E V; Chvalun, S N; Pal'tsev, M A; Panteleev, A A

    2015-08-01

    We compared the structure and mechanical properties of scaffolds based on pure collagen, pure chitosan, and a mixture of these polymers. The role of the composition and structure of scaffolds in the maintenance of cell functions (proliferation, differentiation, and migration) was demonstrated in two experimental models: homogeneous tissue analogues (scaffold populated by fibroblasts) and complex skin equivalents (fibroblasts and keratinocytes). In contrast to collagen scaffolds, pure chitosan inhibited the growth of fibroblasts that did not form contacts with chitosan fibers, but formed specific cellular conglomerates, spheroids, and lose their ability to synthesize natural extracellular matrix. However, the use of chitosan as an additive stimulated proliferative activity of fibroblasts on collagen, which can be associated with improvement of mechanical properties of the collagen scaffolds. The effectiveness of chitosan as an additional cross-linking agent also manifested in its ability to improve significantly the resistance of collagen scaffolds to fibroblast contraction in comparison with glutaraldehyde treatment. Polymer scaffolds (without cells) accelerated complete healing of skin wounds in vivo irrespective of their composition healing, pure chitosan sponge being most effective. We concluded that the use of chitosan as the scaffold for skin equivalents populated with skin cells is impractical, whereas it can be an effective modifier of polymer scaffolds.

  14. Absorbent alginate fibres modified with hydrolysed chitosan for wound care dressings--II. Pilot scale development.

    Science.gov (United States)

    Sweeney, I R; Miraftab, M; Collyer, G

    2014-02-15

    Fibres have been used extensively in wound dressing applications as they provide a high surface area for absorption, ease of fabrication and softness. It is common practice for commercial wound dressings to be produced from natural materials, such a marine polysaccharides, as they are predominantly biocompatible, non-toxic, and often display bioactive properties, such as inherent antimicrobial activity. In this study hydrolysed chitosans were utilised as a sole coagulant for the production of alginate-chitosan fibres via a one-step, direct wet-spinning extrusion process. The levels of chitosan incorporated into the fibres were analysed quantitatively via elemental analysis and qualitatively by staining using Amido Black 10B. It was estimated that the fibres contained between 4.50 and 5.10% (wt.%) chitosan. The presence of chitosan improved tensile properties such as elongation and tenacity of the base alginate fibres. The increased incorporation of chitosan into the fibres also improved the absorption of the fibres in both saline and distilled water; reaching maximum of >30 g/g and >50 g/g, respectively. This work suggests that the observed hydrolysed chitosan content within the fibre may be optimal for the preparation of a novel fibre for wound care application.

  15. Chitosan/Riboflavin-modified demineralized dentin as a potential substrate for bonding.

    Science.gov (United States)

    Fawzy, Amr S; Nitisusanta, Lorraine I; Iqbal, Kulsum; Daood, Umer; Beng, Lu Thong; Neo, Jennifer

    2013-01-01

    Previous studies have suggested different approaches to modify dentin collagen for potential improvement in bonding to dentin. Here, we are proposing a new approach to reinforce dentin collagen fibrils network by chitosan as a reinforcement phase and UVA-activated riboflavin as crosslinking agent within clinically acceptable time-frame as potential substrate for bonding. The effect of modifying demineralized dentin substrates with chitosan/riboflavin, with a gradual increase in chitosan content, was investigated by SEM, nano-indentation, conventional-mechanical testing and hydroxyproline (HYP) release at collagenolytic and/or hydrolytic challenges. The resin/dentin interface morphology, immediate bond strength and short-term bond durability were also investigated using etch-and-rinse dentin adhesive. Modification with chitosan/riboflavin increased the mechanical properties, enhanced the mechanical stability of demineralized dentin substrates against hydrolytic and/or collagenolytic degradation challenges and decreased HYP release with collagenase exposure. When chitosan was added to riboflavin at 20%v/v ratio, significant improvement in bond strength at 24 h and 6 months in distilled water was found indicating the positive dual effect on bonding to dentin. With the gradual increase in chitosan content, obliteration of interfibrillar-spaces that might adversely affect bonding to dentin was found. Although it has a synergetic effect, chitosan content is crucial for any subsequent application in adhesive dentistry.

  16. Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

    Energy Technology Data Exchange (ETDEWEB)

    Benamer, S., E-mail: benamers@yahoo.fr [Division of Nuclear Applications, Centre de Recherche Nucleaire d' Alger, BP-399 Alger-Gare (Algeria); Mahlous, M.; Tahtat, D.; Nacer-Khodja, A.; Arabi, M. [Division of Nuclear Applications, Centre de Recherche Nucleaire d' Alger, BP-399 Alger-Gare (Algeria); Lounici, H.; Mameri, N. [Ecole Nationale Polytechnique d' El-Harrach Alger (Algeria)

    2011-12-15

    Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: > Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. > Crosslinking process improves chemical stability of chitosan beads. > Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. > Increase in grafting degree enhances the adsorption capacity of the material. > Gamma radiation is a powerful tool for an accurate control of the grafting yield.

  17. Borate cross-linked graphene oxide-chitosan as robust and high gas barrier films

    Science.gov (United States)

    Yan, Ning; Capezzuto, Filomena; Lavorgna, Marino; Buonocore, Giovanna G.; Tescione, Fabiana; Xia, Hesheng; Ambrosio, Luigi

    2016-05-01

    Chitosan (CS) is one of the most promising polymers due to its biocompatibility, biodegradability, and natural abundance. However, its poor mechanical and barrier properties make it difficult to satisfy a wide range of applications. Herein, borate ions, originating from the hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan and graphene oxide (GO) nanocomposites. Chitosan films consisting of 1.0 wt% boron and 1.0 wt% GO exhibit a significant improvement in both the toughness and oxygen barrier properties compared to pristine chitosan. In particular the tensile strength of the samples after thermal treatment increases by ~160% compared to pristine chitosan, whereas their oxygen permeability reduces by ~90%. This is ascribed to the chemical crosslinking between chitosan and GO nanoplatelets through borate ions, as well as the formation of a layered morphology with graphene nanoplatelets oriented parallel to the sample surface. The exceptional robust and high gas barrier film has promising application in the packaging industry. The borate-crosslinking chemistry represents the potential strategy for improving properties of other polymer nanocomposites.Chitosan (CS) is one of the most promising polymers due to its biocompatibility, biodegradability, and natural abundance. However, its poor mechanical and barrier properties make it difficult to satisfy a wide range of applications. Herein, borate ions, originating from the hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan and graphene oxide (GO) nanocomposites. Chitosan films consisting of 1.0 wt% boron and 1.0 wt% GO exhibit a significant improvement in both the toughness and oxygen barrier properties compared to pristine chitosan. In particular the tensile strength of the samples after thermal treatment increases by ~160% compared to pristine chitosan, whereas their oxygen permeability reduces by ~90%. This is ascribed to the chemical

  18. Mechanical Reinforcement of Wool Fiber through Polyelectrolyte Complexation with Chitosan and Gellan Gum

    Directory of Open Access Journals (Sweden)

    Khairul Anuar Mat Amin

    2013-10-01

    Full Text Available The formation of polyelectrolyte complex (PEC wool fibers formed by dipping chitosan or gellan gum-treated wool fibers into biopolymer solutions of opposite charge is reported. Treating wool fibers with chitosan (CH and gellan gum (GG solutions containing food dyes resulted in improved mechanical characteristics compared to wool fibers. In contrast, pH modification of the solutions resulted in the opposite effect. The mechanical characteristics of PEC-treated fibers were affected by the order of addition, i.e., dipping GG-treated fibers into chitosan resulted in mechanical reinforcement, whereas the reverse-order process did not.

  19. The Effect of Chitosan and Sodium Alginate on the Growth and Photosynthesis of Soybean

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Seeu coating can make soybean seedling grow more strongly and reinforce the resistance of soybean plant. Sodium alginate and chitosan are high-molecular compound of two different kind,have the characteristic of promoting the crop growth. Using Sodium alginate and chitosan as coating materials under different concentration can improve the growth and photosynthesis obviously and can decrease pollution because of their characteristics. The analysis show that the effects of Sodium Alginate on soybean plant are better than chitosan and the best concentration is 0.50 g @ kg-1

  20. Curcumin-Loaded Chitosan/Gelatin Composite Sponge for Wound Healing Application

    Directory of Open Access Journals (Sweden)

    Van Cuong Nguyen

    2013-01-01

    Full Text Available Three composite sponges were made with 10% of curcumin and by using polymers, namely, chitosan and gelatin with various ratios. The chemical structure and morphology were evaluated by FTIR and SEM. These sponges were evaluated for water absorption capacity, antibacterial activity, in vitro drug release, and in vivo wound healing studies by excision wound model using rabbits. The in vivo study presented a greater wound closure in wounds treated with curcumin-composite sponge than those with composite sponge without curcumin and untreated group. These obtained results showed that combination of curcumin, chitosan and gelatin could improve the wound healing activity in comparison to chitosan, and gelatin without curcumin.

  1. Synthesis and evaluation of PEG-O-chitosan nanoparticles for delivery of poor water soluble drugs: Ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Hassani Najafabadi, Alireza [Department of Chemistry, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran (Iran, Islamic Republic of); Abdouss, Majid, E-mail: phdabdouss44@aut.ac.ir [Department of Chemistry, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran (Iran, Islamic Republic of); Faghihi, Shahab [Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161 (Iran, Islamic Republic of)

    2014-08-01

    Current methods for preparation of PEGylated chitosan have limitations such as harsh de protecting step and several purification cycles. In the present study, a facile new method for conjugating methoxy polyethylene glycol (mPEG) to chitosan under mild condition is introduced to improve water solubility of chitosan and control the release of poor water soluble drugs. The method consists of chitosan modification by grafting the C6 position of chitosan to mPEG which is confirmed by Fourier transformed-infrared (FT-IR) and proton nuclear magnetic resonance ({sup 1}HNMR) analyses. The amine groups at the C2 position of chitosan are protected using sodium dodecylsulfate (SDS) which is removed by dialyzing the precipitation against Tris solution. The chemical structure of the prepared polymer is characterized by FTIR and {sup 1}HNMR. The synthesized polymer is then employed to prepare nanoparticles which are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) for their size and morphology. The nanoparticles are used for encapsulation of ibuprofen followed by in vitro release investigation in gastrointestinal and simulated biological fluids. The chitosan nanoparticles are used as control. The PEGylated nanoparticles show a particle size of 80 nm with spherical morphology. The results clearly show that drug release from PEGylated chitosan nanoparticles is remarkably slower than chitosan. In addition, drug encapsulation and encapsulation efficiency in PEGylated nanoparticles are dependent on the amount of drug added to the formulation being significantly higher than chitosan nanoparticles. This study provides an efficient, novel, and facile method for preparing a nano carrier system for delivery of water insoluble drugs. - Highlights: • A facile novel method for conjugating methoxy polyethylene glycol (mPEG) to chitosan is introduced. • Fabricated PEG

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

    Science.gov (United States)

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

    2013-12-01

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

  3. Biocompatibility of chitosan/Mimosa tenuiflora scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Martel-Estrada, Santos Adriana [Instituto de arquitectura diseño y arte, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); Rodríguez-Espinoza, Brenda [Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Anillo envolvente del PRONAF y Estocolmo, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); Santos-Rodríguez, Elí [ICTP Meso-American Centre for Theoretical Physics (ICTP-MCTP)/Universidad Autónoma de Chiapas, Ciudad Universitaria, Carretera Zapata Km. 4, Real del Bosque (Terán), C.P. 29040 Tuxtla Gutiérrez, Chiapas (Mexico); Jiménez-Vega, Florinda [Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Anillo envolvente del PRONAF y Estocolmo, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); García-Casillas, Perla E.; Martínez-Pérez, Carlos A. [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); and others

    2015-09-15

    Highlights: • The porosity of the composites allow biological processes for the cell adaptation on the scaffolds. • The composites improve the viability and proliferation of cells. • Composition of the scaffold plays an important role in the biocompatibility. • The results indicate that Mimosa Tenuiflora can induce the differentiation of osteoblast cells. - Abstract: In search of a plant that exhibits osteogenic activity, Mimosa tenuiflora (M. tenuiflora) cortex represents the opportunity to create a biomaterial that, together with the chitosan, is osteoconductive and promote better and rapid regeneration of bone tissue. Thus, the composite of chitosan/M. tenuiflora cortex fabricated will have properties of biocompatibility and allow the osteoblast proliferation. Composites were developed with different concentrations of chitosan/M. tenuiflora cortex (w/w) using thermally induced phase separation technique (TIPS). To analyze the effects of composite on osteoblasts, primary cultures, each sample was collected on days 1, 3 and 7 after seeding. The evaluation of composites consisted of viability and proliferation tests in which we observed the metabolic activity of the cells using MTT reagent and determined the DNA concentration by means of fluorescence. The expression of the marker alkaline phosphatase (ALP) using p-nitrophenyl phosphate was examined, allowing the observation to the activity of proliferation and differentiation of osteoblastic cells. Moreover, an analysis of biomineralization was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy, infrared spectroscopy and X-ray diffraction. The results showed that 80/20 chitosan/M. tenuiflora cortex biocomposite has the best performance with osteoblasts compared to biomaterials 100/0 and 70/30 chitosan/M. tenuiflora composites. Finally, it was determined that the composite of chitosan/M. tenuiflora cortex presents no cytotoxicity and increases the capacity of the osteoblasts

  4. FERROFERRIC OXIDE/CHITOSAN SCAFFOLDS WITH THREE-DIMENSIONAL ORIENTED STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Jia-han Ke; Zheng-ke Wang; Yin-zhe Li; Qiao-ling Hu; Jie Feng

    2012-01-01

    A facile approach to construct ferroferric oxide/chitosan composite scaffolds with three-dimensional oriented structure has been explored in this research.Chitosan and ferroferric oxide are co-precipitated by using an in situ precipitation method,and then lyophilized to get the composite scaffolds.XRD indicated that Fe3O4 was generated during the gel formation process,and increasing the content of magnetic particles could destruct the crystal structure of chitosan.When the content of magnetic particles is lower than 10%,the layer-by-layer structure and wheel spoke structure are coexisting in the scaffolds.Increasing the content of magnetic particles,just layer-by-layer structure could be observed in the scaffolds.Ferroferric oxide particles were uniformly distributed in the matrix,the size of which was about 0.48 μm in diameter,2 μm in length.Porosity of magnetic chitosan composite scaffolds is about 90%.When the ratio of ferroferric oxide to chitosan is 5/100,the compressive strength of the material is 0.4367 MPa,which is much higher than that of pure chitosan scaffolds,indicating that the layer-by-layer and wheel spokes complex structure is beneficial for the improvement of the mechanical properties of chitosan scaffolds.However,increasing the content of ferroferric oxide,the compressive strength of scaffolds decreased,because of the decreasing of chitosan crystallization and aggregation of magnetic particles as stress centralized body.Another reason is that the layer-by-layer and wheel spokes complex structure makes bigger contributions for the compressive strength than the layer-by-layer structure does.Three-dimensional ferroferric oxide/chitosan scaffolds could be used as hyperthermia generator system,improving the local circulation of blood,promoting the aggradation of calcium salt and stimulating bone tissue regeneration.

  5. Application of irradiated chitosan for fruit preservation

    Energy Technology Data Exchange (ETDEWEB)

    Lan, K.N. [Post-harvest Technology Institute, 4, Ngo Quyen-Ha Noi (Viet Nam); Lam, N.D. [Ha Noi Radiation Center, VAEC, 5T-160, Nghiado, Tuliem, Ha Noi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  6. Synthesis of Chitosan Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, 1HNMR and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

  7. Chitosan-supported Borohydride Reducing Agent

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new chitosan-supported borohydride reducing reagent (CBER) was prepared by treatment of KBH4 with the resin of chitosan derivative, which was first synthesized fiom the reaction of cross-linked chitosan microsphere with glycidyl trimethylammonium chloride. CBER could reduce aromatic carbonyl compound to corresponding alcohol.

  8. Photochemical and antimicrobial properties of silver nanoparticle-encapsulated chitosan functionalized with photoactive groups.

    Science.gov (United States)

    Mathew, Thomas V; Kuriakose, Sunny

    2013-10-01

    Chitosan was functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid by the coupling of the hydroxyl functional groups of chitosan with carboxylic acid group of the dye by DCC coupling method. The silver nanoparticles were prepared by sol-gel method of nanoparticle synthesis. Silver nanoparticle-encapsulated functionalized chitosan was prepared by the phase transfer method. The products were characterized by FTIR, UV-Vis, fluorescence and NMR spectroscopic methods and by SEM and TEM analysis. The photochemical properties of silver nanoparticle-encapsulated chitosan functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid was studied in detail. The light-fastening properties of the chromophoric system was enhanced when attached to chitosan, and it can be further improved by the encapsulation of silver nanoparticles. The antibacterial analysis of silver nanoparticle-encapsulated functionalized chitosan was carried out against Staphylococcus aureus and Escherichia coli and against fungal species such as Aspergillus flavus and Aspergillus terreus. This study showed that silver nanoparticles-encapsulated functionalized chitosan can be used for antibacterial and antifungal applications.

  9. The molecular understanding of interfacial interactions of functionalized graphene and chitosan

    Science.gov (United States)

    Zhang, Hong-ping; Luo, Xue-gang; Lin, Xiao-yan; Lu, Xiong; Tang, Youhong

    2016-01-01

    Graphene-reinforced chitosan scaffolds have been extensively studied for several years as promising hard tissue replacements. However, the interfacial interactions between graphene and chitosan are strongly related to the solubility, processability, and mechanical properties of graphene-reinforced chitosan (G-C) composites. The functionalization of graphene is regarded as the most effective way to improve the abovementioned properties of the G-C composite. In this study, the interfacial interactions between chitosan and functionalized graphene sheets with carboxylization (COOH-), amination (NH2-), and hydroxylation (OH-) groups were systematically studied at the electronic level using the method of ab initio simulations based on quantum mechanics theory and the observations were compared with reported experimental results. The covalent linkages between COOH-modified graphene and the chitosan units were demonstrated and the combination of multi-functionalization on graphene could regulate the interfacial interactions between graphene and the chitosan. The interfacial interactions between chitosan and properly functionalized graphene are critical for the preparation of G-C-based composites for tissue engineering scaffolds and other applications.

  10. Effectiveness of Postharvest Treatment with Chitosan to Control Citrus Green Mold

    Directory of Open Access Journals (Sweden)

    Mohamed El Guilli

    2016-03-01

    Full Text Available Control of green mold, caused by Penicillium digitatum, by fungicides raises several problems, such as emergence of resistant pathogens, as well as concerns about the environment and consumers’ health. As potential alternatives, the effects of chitosan on green mold disease and the quality attributes of citrus fruits were investigated. Fruits were wounded then treated with different concentrations of chitosan 24 h before their inoculation with P. digitatum. The results of in vitro experiment demonstrated that the antifungal activity against P. digitatum was improved in concert to the increase of chitosan concentration. In an in vivo study, green mold was significantly reduced by chitosan treatments. In parallel, chitinase and glucanase activities were enhanced in coated fruits. Evidence suggested that effects of chitosan coating on green mold of mandarin fruits might be related to its fungitoxic properties against the pathogen and/or the elicitation of biochemical defense responses in coated fruits. Further, quality attributes including fruit firmness, surface color, juice content, and total soluble solids, were not affected by chitosan during storage. Moreover, the loss of weight was even less pronounced in chitosan-coated fruit.

  11. THE DEVELOPMENT OF CHITOSAN NANOPARTICLES FROM HIBISCUS SABDARIFFA L CALYX EXTRACT FROM INDONESIA AND THAILAND

    Directory of Open Access Journals (Sweden)

    Nurkhasanah*, Tedjo Yuwono, Laela Hayu Nurani, Muhammad Ikhwan Rizki and Krisana Kraisintu

    2015-05-01

    Full Text Available Rosella (Hibiscus sabdariffa L calyx has been reported to have an antioxidant activity. Antocyanidin is the major compound of rosella and has low bioavailability as an ionic form. Rosella extract is an ucceptable due to high acidity. Development of chitosan nanoparticle from Hibiscus sabdariffa extract were expected to improve the bioavailability and the acidity problem. We studied the optimum pH and composition ratios of chitosan, extract and tripolyphosphate (TPP to develop chitosan-nanoparticle of rosella extract. We used rosella calyx both from Indonesia and Thailand to compare the physical characteristic the extract and nanoparticles. Rosella was extracted using 60% ethanol and water, followed by evaporation using evaporator and dried by freezedryer. The optimum formation of chitosan-nanoparticles of rosella extract were observed including pH formation and composition ratios between extract: chitosan: TPP. The physical charactersitics of nanoparticles were observed using transmission electron microscope (TEM and particle size analyzer (PSA. We found that optimum composition of extract: chitosan : TPP ratios were 2 : 1 : 0.1, with optimum formation of chitosan in acetate buffer pH 4. The characteristic of nanoparticles were spherical shapes with particles size range 60 to 300 nm, polydispersity index around 0.3 and zeta potential 39.19 to 62.26 mV. The nanoparticles has high entrapment efficiency of flavonoid active compound of 81.98 to 83.83%.

  12. Preparation, physicochemical and pharmaceutical characterization of chitosan from Catharsius molossus residue.

    Science.gov (United States)

    Ma, Jiahua; Xin, Chao; Tan, Chengjia

    2015-09-01

    Polypeptide from Catharsius molossus L. is an active ingredient in the treatment of benign prostatic hyperplasia. The residue after extraction is harmful to the environment and is also a waste of resources. Chitosan was extracted from C. molossus L. residue with chemical methods and with an improved intermittent heating method. Physicochemical and pharmaceutical characteristics of chitosan from C. molossus L. and shrimp were mainly measured by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM). The results showed chitosan from C. molossus L. was superior to commercial medical-grade chitosan from shrimp in the aspects of degree of deacetylation, crystallinity, heavy metal content, viscosity, protein residue, ash content, and in vitro adhesion. In addition, properties of chitosan membrane were studied, including water vapor permeability, light transmittance, enzymatic hydrolysis, swelling behavior, mechanical properties, and SEM images. It was found that the membrane of chitosan from C. molossus L. had better performance. This preliminary result shows chitosan from C. molossus L. is more suitable than shrimp's as a pharmaceutical excipient in colonic adhesive drug delivery system.

  13. Evaluation of Osseointegration Ability of Porous Polyethylene Implant (Medpor Treated with Chitosan

    Directory of Open Access Journals (Sweden)

    Kwang Kim

    2014-01-01

    Full Text Available Purpose. We suggest a successful and simple Medpor treated way with chitosan and evaluate more improved osseointegration ability of it than the orignal. Materials and Methods. Medpor was punched into circular shape and dipped into the chitosan gel solution. The Medpor plates soaked with chitosan were identified by the SEM images. We evaluated the growth rate of MC3T3-E1 cell using Von Kossa staining and MTT assay as in vitro experiment. And we implanted both Medpor plates into skull of domestic rabbits for in vivo experiment. We evaluated the osseointegration result with an optical microscope in postoperative 3 weeks and 6 weeks histologically. Results. The in vitro MC3T3-E1 cell growth rate on Medpor soaking with chitosan was faster than the original one in both Von Kossa staining and MTT assay. In animal test, Medpor soaking with chitosan shows more pronounced new bone than original Medpor too. Conclusion. Medpor soaking with chitosan was a successful modification. It is believed that the upgraded osseointegration ability of Medpor soaking with chitosan gives many benefits to clinicians using a Medpor implant for oral and maxillofacial reconstruction surgery.

  14. Use of maize cob for production of particleboard

    Directory of Open Access Journals (Sweden)

    Mário Vanoli Scatolino

    2013-08-01

    Full Text Available Agricultural residues are materials generated in large quantities in Brazil and can accumulate to such extent as to cause environmental problems. Among agricultural residues, maize cob is one worthy of notice, and an alternative use for maize cob would be to produce particleboard panels in association with wood particles. This study aimed to evaluate the feasibility of using maize cob for production of particleboard panels. The following maize cob percentages were used: 0%, 25%, 50%, 75% and 100%, in association with particles of Pinus oocarpa wood. Panels were made with 8% of urea formaldehyde and 1% of paraffin (based on dry weight of particles. For compressing the panels, a pressure of 3.92 MPa was applied at a temperature of 160º C, for 8 minutes. Increased replacement of pinewood by maize cob residue promoted significant improvements to the properties water absorption after two hours of immersion, thickness swelling after two and after twenty-four hours of immersion. Mechanical properties had a decreasing correlation with the maize cob percentage being incorporated.

  15. The Role of cis Regulatory Evolution in Maize Domestication

    Science.gov (United States)

    Lemmon, Zachary H.; Bukowski, Robert; Sun, Qi; Doebley, John F.

    2014-01-01

    Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem). Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes) show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues. PMID:25375861

  16. The role of cis regulatory evolution in maize domestication.

    Directory of Open Access Journals (Sweden)

    Zachary H Lemmon

    2014-11-01

    Full Text Available Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem. Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues.

  17. The role of cis regulatory evolution in maize domestication.

    Science.gov (United States)

    Lemmon, Zachary H; Bukowski, Robert; Sun, Qi; Doebley, John F

    2014-11-01

    Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem). Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes) show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues.

  18. Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting

    Directory of Open Access Journals (Sweden)

    Laura De Matteis

    2016-09-01

    Full Text Available The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol (PEG grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis. Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery.

  19. Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting

    Science.gov (United States)

    De Matteis, Laura; Alleva, Maria; Serrano-Sevilla, Inés; García-Embid, Sonia; Stepien, Grazyna; Moros, María; de la Fuente, Jesús M.

    2016-01-01

    The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery. PMID:27706041

  20. Simulation of water use process by film mulched cultivated maize based on improved AquaCrop model and its verification%基于改进AquaCrop模型的覆膜栽培玉米水分利用过程模拟与验证

    Institute of Scientific and Technical Information of China (English)

    杨宁; 孙占祥; 张立桢; 郑家明; 冯良山; 李开宇; 张哲; 冯晨

    2015-01-01

    -mulched maize was among ±6%. In addition, R2, RRMSE, CE of grain and water use efficiency during 2011 to 2013 were 0.96 and 0.93, 0.042 and 0.06, 0.91 and 0.89, respectively. The developed AquaCrop model predicted maize grain yield with higher accuracy and performed better yield than water use efficiency for mulching plastic film maize, which indicated this improved model were better mechanism and application for simulated maize mulching. The present research implicated that the developed AquaCrop model can be applied to the same to semi-arid region and simulated maize potential, or prescribing yield in response to water and temperature limiting factors under climate change.

  1. Chitosan and carboxymethyl-chitosan capping ligands: Effects on the nucleation and growth of hydroxyapatite nanoparticles for producing biocomposite membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dumont, Vitor C.; Mansur, Alexandra A.P.; Carvalho, Sandhra M.; Medeiros Borsagli, Fernanda G.L.; Pereira, Marivalda M.; Mansur, Herman S., E-mail: hmansur@demet.ufmg.br

    2016-02-01

    predominant calcium phosphate phase produced during the co-precipitation aqueous process for both the chitosan and CMC biocomposites. These novel hybrid systems based on chitosan and chitosan-derivatives with nHA composites were non-cytotoxic to a human osteoblast-like model cell line (SAOS) according to MTT in vitro assays. Moreover, the CMC-nHA biocomposites revealed a striking improvement in the cell viability response compared to the CHI-nHA biocomposite, which was attributed to the much higher surface area caused by the refinement of the nanoparticles size. Thus, the results of this study demonstrate that these novel bionanocomposite membranes offer promising perspectives as biomaterials for potential repair and replacement of cartilage and bone tissues. - Highlights: • Nanohydroxyapatite particles prepared using chitosan-based ligands via aqueous route • Effects of chitosan and CMC on the nucleation and growth of hydroxyapatite particles • Biocomposites of HA nanoparticles in chitosan and O-carboxymethyl chitosan matrices • Nanocomposites were non-cytotoxic tested with SAOS cells using in vitro MTT assay • Chitosan bionanocomposites were produced for potential bone repair bioapplications.

  2. LYOTROPIC LIQUID CRYSTALLINE BEHAVIOR OF FIVE CHITOSAN DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    Yan-ming Dong; Zhi-qiang Li

    1999-01-01

    Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubilitythan chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two Nsubstituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three Osubstituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.

  3. Influence of Water Stress on Endogenous Hormone Contents and Cell Damage of Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    Chunrong Wang; Aifang Yang; Haiying Yin; Juren Zhang

    2008-01-01

    Phytohormones play critical roles In regulating plant responses to stress. We Investigated the effects of water stress Induced by adding 12% (w/v) polyethylene glycol to the root medium on the levels of abscisic acid (ABA), indole-3-acid (IAA), zeatin (ZT), and gibberellin3 (GA3) in maize leaves. The results suggested that water stress had significant effects on the four hormone levels. There was a transient increase in the IAA content during the initial stage of adaptation to water stress in maize leaves, but it dropped sharply thereafter in response to water stress. ABA content increased dramatically in maize leaves after 24 h of exposure to water stress, and then the high levels of ABA were maintained to the end, The contents Of ZT and GA3 rapidly declined in maize leaves subjected to water stress. The effects of water stress on chlorophyll content, electrolyte leakage and malondialdehyde levels in maize leaves were also studied. The variation of cell damage was negatively correlated with ZT and GA3 levels in maize leaves under water stress. Thus, we explored the roles of ZT and GA3 on the growth of maize seedlings under water stress by exogenous application. It is possible that both ZT and GA3 were effective in protecting maize seedlings from water stress, which would be of great importance for the improvement of drought tolerance in maize by genetic manipulation.

  4. Core shell methyl methacrylate chitosan nanoparticles: In vitro mucoadhesion and complement activation

    Directory of Open Access Journals (Sweden)

    F Atyabi

    2011-10-01

    Full Text Available Background and the purpose of the study: Studies show that chitosan nanoparticles increase mucoadhesivity and penetration of large molecules across mucosal surface. The aim of the present study was to investigate the use of thiolated chitosan in the development of polysaccharide-coated nanoparticles in order to confer specific functionality to the system. Methods: Methyl methacrylate nanoparticles were coated with thiolated chitosan using a radical polymerization method. Thiolation was carried out using glutathione (GSH to improve mucoadhesivity and permeation enhancing properties of chitosan. Mucoadhesion studies were carried out by calculating the amount of mucin adsorbed on nanoparticles in a specific period of time. Complement consumption was assessed in human serum (HS by measurement of the hemolytic capacity of the complement system after contact with nanoparticles.   Results:   The FT-IR and 1HNMR spectra both confirmed the synthesis and showed the conjugation of thiolated chitosan to methyl methacrylate (MMA homopolymer. Nanoparticles were spherical having a mean diameter within the range of about 334-650 nm and their positive zeta potential values indicated the presence of the cationic polysaccharide at the nanoparticle surface. Increasing the amount of thiolated chitosan led to mucoadhesivity and complement activation. However there was not dose dependent correlation between these phenomenons and the absence of thiolated chitosan led to particles with larger size, and without ability to activate complement process. Major conclusion: It can be concluded that nanoparticles could be used for the mucosal delivery of peptides and proteins. Results show that the thiolated chitosan had higher mucoadhesion and complement activation than unmodified chitosan.

  5. 玉米外引自交系及改良系穗部性状的遗传分析%Genetic Analysis of Ear Traits of Exotic and Improved Maize Inbred Lines

    Institute of Scientific and Technical Information of China (English)

    郭琦; 李继竹; 杨伟光; 尹日成

    2013-01-01

    以7个外引玉米自交系及改良系和6个国内骨干自交系按照 NCⅡ设计组配42个杂交组合,对其8个主要穗部性状进行了遗传分析。结果表明:7923、6WC、J1782的一般配合力较高,是综合性状较好的自交系。配合力与产量相关分析结果表明:一般配合力比特殊配合力相关明显,在玉米育种实践中应重视对性状一般配合力的选择。特殊配合力和杂种优势分析结果表明:7923×8F349,7923×丹340等9个组合为高产杂交组合。遗传力分析结果表明:穗长、穗粗和穗行数的广义遗传力和狭义遗传力均较大,可早代选择;子粒长、秃尖长、出子率、百粒重的狭义遗传力相对较低,不应早代选择。%Seven exotic and improved maize inbred lines were crossed with six elite Chinese inbred lines and 42 combinations were produced according to NCⅡ design.Eight main ear traits were genetically ana-lyzed.The results showed that inbred lines 7923,6WC and J1782 had high combining ability,which were good lines;combining ability and yield correlation analysis showed that in maize breeding,GCA was more important than SCA;we selected 7 high-yield combinations through heterosis analysis,like 7923 × 8-F349;broad heritability and narrow heritability of ear length,ear diameter and ear row number were high,so they could be selected in early generation;narrow heritability of kernel length,length of bare tip,seed ratio and hundred-grain weight was low,and they are easy to be impacted by environment,so they should not be selected in early generation.

  6. Combining ability of twelve maize populations

    Directory of Open Access Journals (Sweden)

    Vacaro Elton

    2002-01-01

    Full Text Available Genetic progress depends on germplasm quality and breeding methods. Twelve maize populations and their crosses were evaluated to estimate combining ability and potential to be included as source populations in breeding programs. Plant height, point of insertion of the first ear, number of ears per plant, number of grains per ear, root and stalk lodging and grain yield were studied in two locations in Brazil, during the 1997/98 season. Genotype sum of squares was divided into general (GCA and specific (SCA combining ability. Results indicated the existence of genetic divergence for all traits analyzed, where additive effects were predominant. The high heterosis levels observed, mainly in Xanxerê, suggested the environmental influence on the manifestation of this genetic phenomenon. Populations revealed potential to be used in breeding programs; however, those more intensively submitted to selection could provide larger genetic progress, showing the importance of population improvement for the increment of the heterosis in maize.

  7. Methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan as a new chitosan derivative: Synthesis, characterization, cytotoxicity and antibacterial activity.

    Science.gov (United States)

    Rahmani, Soheila; Mohammadi, Zohreh; Amini, Mohsen; Isaei, Elham; Taheritarigh, Sadegh; Rafiee Tehrani, Niyousha; Rafiee Tehrani, Morteza

    2016-09-20

    Chitosan, as a biocompatible polymer, is very attractive for biomedical applications. Continues studies are performing for improving its physicochemical features in order to make it more suitable for such approaches. In this study, methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan (MABCC) was synthesized,as a new chitosan derivative, in three steps. The investigations were carried out using FTIR, NMR, TGA and zeta potential measurement. Antibacterial and cell viability assessments were performed on four bacterial strains and two cell lines respectively. FTIR and NMR results showed that all substitution reactions were successfully carried out. Zeta potential of MABCC at various pH especially alkaline pH was greater than chitosan and it revealed increasing the solubility of the derivative. Antibacterial activity of MABCC was extremely greater than chitosan especially in Gram positive bacteria.Furthermore,it had no significant cytotoxicity against MCF-7 and Skov-3 cell lines in comparison to chitosan. These findings confirm that this new derivative can be introduced as a suitable compound for biomedical purposes.

  8. Applying CSM-CERES-Maize to define a sowing window for irrigated maize crop - The Riacho´s Farm case study

    Directory of Open Access Journals (Sweden)

    Denise Freitas Silva

    2011-08-01

    Full Text Available Irrigation use constitutes an alternative to improve maize production in Central Minas Gerais State, Brazil. However, even under adequate water supply conditions, other environmental factors may influence maize crop growth and development and may, ultimately, affect grain yield. This study aimed to establish a sowing window for irrigated maize crop, based on simulation results obtained with the decision support model CSM-CERES-Maize. Simulations were made for crop management conditions of Riacho´s Farm, located in Matozinhos, Minas Gerais State, Brazil. It was employed the model´s seasonal tool, along with a data set containing 46 years of weather data records, to simulate maize yield for weekly sowing scenarios, starting on August 1st and ending on July 24th of each year. One defined an irrigated maize sowing window, taking into account the yield break risk that a farmer would be willing to take. The model proved to be an interesting tool to assist in decision making, regarding crop and irrigation management, for an irrigated maize production system. Assuming a 10% yield break in the expected average maximum maize yield, it was defined as sowing window, the period from January 23rd to March 6th, with February 20th as the best sowing date. Other sowing windows may be established according to the risk that the farmer would be willing to take.

  9. Maize variety and method of production

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Markus; Hake, Sarah; Kraemer, Florian J

    2014-05-27

    The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

  10. SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    杨宇民; 邵健; 姚成

    2001-01-01

    A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FT-IR spectra analysis. The adsorption properties of sulfhydryl chitosan for Cu( Ⅱ ), Cd( Ⅱ ), Pb( Ⅱ ), Cr( Ⅲ ) and Ni( Ⅱ ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb( Ⅱ ), Cu( Ⅱ ) and Cd( Ⅱ ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu( Ⅱ ) Cd ( Ⅱ )and Pb( Ⅱ ) could be eluted by diluted chlorhydric acid.

  11. Electrospinning of Chitosan-Xanthan Nanofibers

    DEFF Research Database (Denmark)

    Shekarforoush, Elhamalsadat; Mendes, Ana Carina Loureiro; Chronakis, Ioannis S.

    Electrospun chitosan-xanthan gum nanofibers were produced and the correlation between the rheological properties of chitosan-xanthan solutions and electrospinability were investigated at different xanthan gum concentrations. Uniform chitosan-xanthan nanofibers with diameters ranging from 382......+182 to 842+296 nm were developed based on the chitosan-xanthan gum content. Overall chitosan-xanthan gum solutions exhibited shear thinning behavior for all the concentrations tested, which tended to increase with the increase of concentration of xanthan. Furthermore the electrical conductivity...... of the chitosan-xanthan solutions was observed to increase with the increase of xanthan gum concentrations. We can conclude that the optimal electrospinning process is directed by the apparent viscosity properties and the electrical conductivity of the chitosan-xanthan solutions. We are currently investigating...

  12. SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    杨宇民; 邵健; 姚成

    2001-01-01

    A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confrrmed by elemental analysis and FI'-IR spectra analysis. The adsorption properties of sulthydryl chitosan for Cu(Ⅱ ), Cd(Ⅱ ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ) and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.

  13. LOW MOLECULAR WEIGHT O-CARBOXYMETHYLATED CHITOSANS DERIVED FROM IRRADIATED CHITOSAN AND THEIR ANTIBACTERIAL ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    Xu-pin Zhuang; Xiao-fei Liu; Zhi Li; Yun-lin Guan; Kang-de Yao

    2004-01-01

    Original chitosan with My of 2.7 × 10 5 was degraded by irradiation with y-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when Mv is equal to 2 × 10 5.

  14. Dietary chitosan enhances hepatic CYP7A1 activity and reduces plasma and liver cholesterol concentrations in diet-induced hypercholesterolemia in rats.

    Science.gov (United States)

    Moon, Min-Sun; Lee, Mak-Soon; Kim, Chong-Tai; Kim, Yangha

    2007-01-01

    The present study was performed to elucidate the hypocholesterolemic action of chitosan on the diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats (n=24) were fed with chitosan-free diet (Control), diets containing 2% or 5% chitosan for 4 weeks. Hypercholesterolemia was induced by adding 1% cholesterol and 0.5% cholic acid to all diets. Body weight gain and food intake of rats did not differ among the groups. The chitosan treated groups showed significant improvement in the plasma concentration of total cholesterol and LDL-cholesterol compared to the control group (pCYP7A1), the rate-limiting enzyme in the conversion of cholesterol to bile acids, was increased by 123% and 165% for the 2% or 5% chitosan diets, respectively. These findings suggest that enhancement of hepatic CYP7A1 activity may be a mechanism, which can partially account for the hypocholesterolemic effect of dietary chitosan in cholesterol metabolism.

  15. Development of a low fat fresh pork sausage based on chitosan with health claims: impact on the quality, functionality and shelf-life.

    Science.gov (United States)

    do Amaral, Deborah S; Cardelle-Cobas, Alejandra; do Nascimento, Bárbara M S; Monteiro, Maria J; Madruga, Marta S; Pintado, Maria Manuela E

    2015-08-01

    A low fat fresh pork sausage based on chitosan was developed with the objective of obtaining a new functional meat product with improved properties and health claims promoting cholesterol reduction. Sausages were formulated with chitosan (2%, w/w) and different fat levels (5%, 12.5% and 20%, w/w). The results indicated that incorporation of 2% chitosan into produced pork sausages with health claims of reduction of cholesterol is technologically feasible. In addition, the chitosan reduced the microbial growth, revealing interesting fat and water absorption capacities, reduced lipid oxidation, provided greater stability in terms of colorimetric parameters and promoted positive firmer texture and gumminess. The reduction of fat content to levels of 5% was positively achieved with the incorporation of chitosan. Sensorial analysis showed that panelists did not detect any significant difference in taste and any unfavorable effect on the sausage appearance as a consequence of chitosan addition and variation of fat.

  16. Nutritive value of maize silage in relation to dairy cow performance and milk quality.

    Science.gov (United States)

    Khan, Nazir A; Yu, Peiqiang; Ali, Mubarak; Cone, John W; Hendriks, Wouter H

    2015-01-01

    Maize silage has become the major forage component in the ration of dairy cows over the last few decades. This review provides information on the mean content and variability in chemical composition, fatty acid (FA) profile and ensiling quality of maize silages, and discusses the major factors which cause these variations. In addition, the effect of the broad range in chemical composition of maize silages on the total tract digestibility of dietary nutrients, milk production and milk composition of dairy cows is quantified and discussed. Finally, the optimum inclusion level of maize silage in the ration of dairy cows for milk production and composition is reviewed. The data showed that the nutritive value of maize silages is highly variable and that most of this variation is caused by large differences in maturity at harvest. Maize silages ensiled at a very early stage (dry matter (DM) maize silages ensiled at DM contents of 300-350 g kg(-1), and then declined slightly at further maturity beyond 350 g kg(-1). The increases in milk (R(2) = 0.599) and protein (R(2) = 0.605) yields with maturity of maize silages were positively related to the increase in starch/NDF ratio of the maize silages. On average, the inclusion of maize silage in grass silage-based diets improved the forage DMI by 2 kg d(-1), milk yield by 1.9 kg d(-1) and milk protein content by 1.2 g kg(-1). Further comparisons showed that, in terms of milk and milk constituent yields, the optimum grass/maize silage ratio depends on the quality of both the grass and maize silages. Replacement of grass silage with maize silage in the ration, as well as an increasing maturity of the maize silages, altered the milk FA profile of the dairy cows, notably, the concentration of the cis-unsaturated FAs, C18:3n-3 and n-3/n-6 ratio decreased in milk fat. Despite variation in nutritive value, maize silage is rich in metabolizable energy and supports higher DMI and milk yield. Harvesting maize silages at a DM content

  17. Uptake of mercury by thiol-grafted chitosan gel beads.

    Science.gov (United States)

    Merrifield, John D; Davids, William G; MacRae, Jean D; Amirbahman, Aria

    2004-07-01

    This study describes the synthesis and characterization of thiol-grafted chitosan beads for use as mercury (Hg) adsorbents. Chitosan flakes were dissolved and formed into spherical beads using a phase inversion technique, then crosslinked to improve their porosity and chemical stability. Cysteine was grafted onto the beads in order to improve the adsorption affinity of Hg to the beads. The beads possessed an average diameter of 3.2 mm, porosity of 0.9, specific surface area of approximately 100 m2/g, average pore size of approximately 120 angstroms, and specific gravity of 2.0. Equilibrium and kinetic uptake experiments were conducted to study the uptake of Hg by the beads. The adsorption capacity was approximately 8.0 mmol-Hg/g-dry beads at pH 7, and decreased with decreasing pH. Hg adsorption kinetics was modeled as radial pore diffusion into a spherical bead with nonlinear adsorption. Use of the nonlinear Freundlich isotherm in the diffusion equation allowed modeling of the uptake kinetics with a single tortuosity factor of 1.5 +/- 0.3 as the fitting parameter for all initial Hg concentrations, chitosan loadings, and agitation rates. At agitation rates of 50 and 75 rpm, where uptake rate was reduced significantly due to the boundary layer effect, the mass transfer coefficient at the outside boundary was also used as a fitting parameter to model the kinetic data. At agitation rates higher than 150 rpm, pore diffusion was the rate-limiting step. The beads exhibited a high initial uptake rate followed by a slower uptake rate suggesting pore diffusion as the rate-determining step especially at high agitation rates. Higher uptake rates observed in this study compared to those in a previous study of chitosan-based crab shells indicate that dissolution and gel formation increase the porosity and pore accessibility of chitosan.

  18. Phase-separated chitosan-fibrin microbeads for cell delivery.

    Science.gov (United States)

    Chen, Zhewei; Wang, Limin; Stegemann, Jan P

    2011-01-01

    Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan-fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 µm to 38 ± 10 µm using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications.

  19. Novel Chitosan-based Biomaterials

    Institute of Scientific and Technical Information of China (English)

    Mingchun Li; Meihua Xin

    2005-01-01

    @@ 1Introduction Chitosan with two long side chains of N-alkyl group is an important amphiphilic material, which has potential application in tissue engineering and drug delivery system. In this paper the amphiphilic N, N-dilauryl chitosan has been prepared by the phase transfer catalysis. The π-A isotherms of the products were measured in order to find some fundamental data for making self-assembled vesicles out of this kind of material. The LB film experiment indicates that N, N-dilauryl chitosan can form ultrathin LB film with highly ordered layer structure and smooth surface. The thickness of each layer of the LB film was measured as 1.74 nm by XRD.

  20. In Vitro Biomineralization of Glutaraldehyde Crosslinked Chitosan/Glutamic Acid Films

    Institute of Scientific and Technical Information of China (English)

    FENG Fang; LIU Yu; ZHAO Binyuan; HU Keao

    2009-01-01

    In vitrobiomineralization ofglutaraldehyde crosslinked chitosan/glutamicacid films were studied. IR and ESCA (electron spectroscopy for chemical analysis) determinations confirm that chitosan and glutamic acid are successfully crosslinked by glutaraldehyde to form chitosan-glutamic acid surfaces. Composite films were soaked in saturated Ca(OH)2 solution for 8 d and then immersed in simulated body fluid (SBF) for more than 20 d. Morphological characterizations and structure of cal-cium phosphate coatings deposited on the films were studied by SEM, XRD, and EDAX (energy dispersive X-ray analysis). Initially, the treatment in SBF results in the formation of single-layer cal-cium phosphate particles over the film surface. As immersion time increases, further nucleation and growth produce the simulated calcium-carbonate hydroxyapatite coating. ICP results show Ca/P ratio of calcium phosphate coating is a function of SBF immersion time. The inducing of glutamic acid improves the biomineralization property of chitosan films.

  1. Investigation the Porous Collagen-Chitosan /Glycosaminoglycans for Corneal Cell Culture as Tissue Engineering Scaffold

    Institute of Scientific and Technical Information of China (English)

    LI Qin-Hua; CHEN Jian-Su

    2005-01-01

    The objective of this study was to produce the porous collagen-chitosan/Glycosanminglycans (GAG) for corneal ceil-seed implant as a three-dimensional tissue engineering scaffold to improve the regeneration corneas. The effect of various content of glycerol as form porous agent to collagen-chitosan/GAG preserved a porous dimensional structure was investigated. The heat-drying was used to prepare porous collagen-chitosan /GAG scaffold. The pore morphology of collagenchitosan/GAG was controlled by changing the concentration of glycerol solution and drying methods. The porous structure morphology was observed by SEM. The diameter of the pores form 10 to 50 μm. The highly porous scaffold had interconnecting pores. The corneal cell morphology was observed under the light microscope. These results suggest that collagen-chitosan/GAG showed that corneal cell have formed confluent layers and resemble the surface of normal corneal cell surface.

  2. Evaluation of chitosan quaternary ammonium salt-modified resin denture base material.

    Science.gov (United States)

    Song, Rong; Zhong, Zhaohua; Lin, Lexun

    2016-04-01

    Chitosan quaternary ammonium salt displays good antioxidant and antibacterial characteristics and it shows appreciable solubility in water. When added to the traditional denture material to form a resin base, it could promote good oral health by improving the oral environment. In this study, chitosan quaternary ammonium salt was added to the denture material following two different methods. After three months of immersion in artificial saliva, the specimens were tested for tensile strength and were scanned by electron microscope. The murine fibroblast cytotoxicity and antibacterial properties were also tested. The result showed no significant differences in the tensile strength and in the proliferation of murine L929 fibroblast cells. The two structures of chitosan quaternary ammonium salt-modified denture material had different degrees of corrosion resistance and antimicrobial properties. These results indicate that chitosan quaternary ammonium salt-modified resin denture base material has the potential to become a new generation oral denture composite material.

  3. Maize provitamin A carotenoids, current resources and future metabolic engineering challenges.

    Directory of Open Access Journals (Sweden)

    Eleanore T Wurtzel

    2012-02-01

    Full Text Available Vitamin A deficiency is a serious global health problem that can be alleviated by improved nutrition. Development of cereal crops with increased provitamin A carotenoids can provide a sustainable solution to eliminating vitamin A deficiency worldwide. Maize is a model for cereals and a major staple carbohydrate source. Here, we discuss maize carotenogenesis with regard to pathway regulation, available resources, and current knowledge for improving carotenoid content and levels of provitamin A carotenoids in edible maize endosperm. This knowledge will be applied to improve the nutritional composition of related Poaceae crops. We discuss opportunities and challenges for optimizing provitamin A carotenoid biofortification of cereal food crops.

  4. A study on the performance of hyaluronic acid immobilized chitosan film

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yingjun; Guo Li; Ren Li; Yin Shiheng [Biomaterial Research Institute, College of Material Science and Engineering, South China University of Technology, Guangzhou, 510640 (China); Ge Jian; Gao Qianying [State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 (China); Luxbacher, Thomas; Luo Shijing, E-mail: imwangyj@scut.edu.c, E-mail: psliren@scut.edu.c [Anton Paar GmbH, Anton-Paar-Strasse 20, A-8054 Graz (Austria)

    2009-06-15

    In order to improve hydrophilicity and biocompatibility of chitosan, hyaluronic acid was immobilized onto the surface of chitosan film. The structure of films was characterized by Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR), x-ray photoelectron spectroscopy (XPS) and zeta potential. Results confirmed that hyaluronic acid was successfully immobilized on chitosan film. Transparency, water absorption percentage and contact angle of films were characterized. Results showed that there was no significant variation in transparency (p < 0.05) before and after immobilization, the maximum was up to 99% which was enough for corneal regeneration in clinical applications. After the immobilization, the time-dependent contact angle declined sharply (from 91.8 deg. to 67.7 deg. at 100 s). The hydrophilicity was significantly improved. The methylthiazol tetrazolium (MTT) (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to assess cell viability and proliferation. Results showed that human cornea epithelial cells (HCEC) grew better on hyaluronic acid immobilized chitosan films than on chitosan films. The hyaluronic acid immobilized chitosan film could be a promising candidate material for corneal regeneration.

  5. Hydrothermal fabrication of hydroxyapatite/chitosan/carbon porous scaffolds for bone tissue engineering.

    Science.gov (United States)

    Long, Teng; Liu, Yu-Tai; Tang, Sha; Sun, Jin-Liang; Guo, Ya-Ping; Zhu, Zhen-An

    2014-11-01

    Porous carbon fiber felts (PCFFs) have great applications in orthopedic surgery because of the strong mechanical strength, low density, high stability, and porous structure, but they are biologically inert. To improve their biological properties, we developed, for the first time, the hydroxyapatite (HA)/chitosan/carbon porous scaffolds (HCCPs). HA/chitosan nanohybrid coatings have been fabricated on PCFFs according to the following stages: (i) deposition of chitosan/calcium phosphate precursors on PCFFs; and (ii) hydrothermal transformation of the calcium phosphate precursors in chitosan matrix into HA nanocrystals. The scanning electron microscopy images indicate that PCFFs are uniformly covered with elongated HA nanoplates and chitosan, and the macropores in PCFFs still remain. Interestingly, the calcium-deficient HA crystals exist as plate-like shapes with thickness of 10-18 nm, width of 30-40 nm, and length of 80-120 nm, which are similar to the biological apatite. The HA in HCCPs is similar to the mineral of natural bone in chemical composition, crystallinity, and morphology. As compared with PCFFs, HCCPs exhibit higher in vitro bioactivity and biocompatibility because of the presence of the HA/chitosan nanohybrid coatings. HCCPs not only promote the formation of bone-like apatite in simulated body fluid, but also improve the adhesion, spreading, and proliferation of human bone marrow stromal cells. Hence, HCCPs have great potentials as scaffold materials for bone tissue engineering and implantation.

  6. Preparation and characterisation of new-polyaluminum chloride-chitosan composite coagulant.

    Science.gov (United States)

    Ng, Mega; Liana, Ayu E; Liu, Sanly; Lim, May; Chow, Christopher W K; Wang, Dongsheng; Drikas, Mary; Amal, Rose

    2012-10-01

    In this study, the formulation of a novel polyaluminum chloride-chitosan composite coagulant that improves the coagulation process for natural organic matter (NOM) removal was investigated. The performance of the composite coagulant was tested using two water sources (synthetic and natural water) to develop a better understanding on the behaviour of the composite coagulant. Fourier Transform-Infra red (FT-IR) spectroscopy, ferron analysis and zeta potential studies were performed to characterise the composite coagulant. FT-IR analysis showed that there is an intermolecular interaction between Al species and chitosan molecules, while ferron analysis indicated that the distributions of Al(a), Al(b), and Al(c) in PACl-chitosan are different from those in PACl. At a low Al dosage (2.16 mg L⁻¹), a much higher removal of NOM from synthetic water, as evidenced from UV₂₅₄ and Dissolved Organic Carbon (DOC) measurements, was achieved by the composite coagulants in comparison to that removed by PACl or PACl and chitosan added separately. For natural water from the Myponga Reservoir, both polyaluminum chloride (PACl) and PACl-chitosan composite coagulants demonstrated similar dissolved organic carbon (DOC) percentage removal, whereas PACl-chitosan gave a slight improvement in removing the UV₂₅₄ absorbing components of NOM.

  7. Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

    Science.gov (United States)

    Jiang, Liqin; Li, Xuemin; Liu, Lingrong; Zhang, Qiqing

    2013-02-01

    Oral chemotherapy is a key step towards `chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer.

  8. Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer.

    Science.gov (United States)

    Jiang, Liqin; Li, Xuemin; Liu, Lingrong; Zhang, Qiqing

    2013-02-09

    Oral chemotherapy is a key step towards 'chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer.

  9. Determination of physical properties for β-TCP + chitosan biomaterial obtained on metallic 316L substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mina, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Tecno-Academia ASTIN SENA Reginal Valle (Colombia); Castaño, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, J.C., E-mail: julio.cesar.caicedo@correo.univalle.edu.co [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, H.H. [Biologics Research, Biotechnology Center of Excellence, Janssen R& D, LLC, Pharmaceutical Companies of Johnson & Johnson, Spring House, PA 19477 (United States); National Biotechnology & Pharmaceutical Association, Chicago, IL 60606 (United States); Aguilar, Y. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia)

    2015-06-15

    Material surface modification, particularly the deposition of special coatings on the surface of surgical implants, is extensively used in bone tissue engineering applications. β-Tricalcium phosphate/Chitosan (β-TCP/Ch) coatings were deposited on 316L stainless steel (316L SS) substrates by a cathodic electro-deposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-Ray diffraction (XRD), and the results indicated that the crystallographic structure of β-TCP was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that root-mean square values of the β-TCP/Ch coatings decreased by further increasing chitosan percentage. The elastic–plastic characteristics of the coatings were determined by conducting nanoindentation test, indicating that increase of chitosan percentage is directly related to increase of hardness and elastic modulus of the β-TCP/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear of β-TCP/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-TCP/Ch coatings as a function of increasing of the chitosan percentage. This new class of coatings, comprising the bioactive components, is expected not only to enhance the bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. - Highlights: • Superficial phenomenon that occurs in tribological surface of β-tricalcium phosphate-chitosan coatings. • Improvement on surface mechanical properties of ceramic-polymeric and response to surface tribological damage. • β-tricalcium phosphate-chitosan coatings that offer highest performance in the biomedical devices.

  10. MaizeGDB: The Maize Genetics and Genomics Database.

    Science.gov (United States)

    Harper, Lisa; Gardiner, Jack; Andorf, Carson; Lawrence, Carolyn J

    2016-01-01

    MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website ( http://www.maizegdb.org ) are custom interfaces enabling researchers to browse data and to seek out specific information matching explicit search criteria. In addition, pre-compiled reports are made available for particular types of data and bulletin boards are provided to facilitate communication and coordination among members of the community of maize geneticists.

  11. Chitosan as a starting material for wound healing applications

    OpenAIRE

    Patrulea,Viorica; Ostafe, V.; Borchard, Gerrit; Jordan, Olivier

    2015-01-01

    Chitosan and its derivatives have attracted great attention due to their properties beneficial for application to wound healing. The main focus of the present review is to summarize studies involving chitosan and its derivatives, especially N,N,N-trimethyl-chitosan (TMC), N,O-carboxymethyl-chitosan (CMC) and O-carboxymethyl-N,N,N-trimethyl-chitosan (CMTMC), used to accelerate wound healing. Moreover, formulation strategies for chitosan and its derivatives, as well as their in vitro, in vivo a...

  12. A rapid and efficient method for assessing pathogenicity of ustilago maydis on maize and teosinte lines.

    Science.gov (United States)

    Chavan, Suchitra; Smith, Shavannor M

    2014-01-03

    Maize is a major cereal crop worldwide. However, susceptibility to biotrophic pathogens is the primary constraint to increasing productivity. U. maydis is a biotrophic fungal pathogen and the causal agent of corn smut on maize. This disease is responsible for significant yield losses of approximately $1.0 billion annually in the U.S.(1) Several methods including crop rotation, fungicide application and seed treatments are currently used to control corn smut(2). However, host resistance is the only practical method for managing corn smut. Identification of crop plants including maize, wheat, and rice that are resistant to various biotrophic pathogens has significantly decreased yield losses annually(3-5). Therefore, the use of a pathogen inoculation method that efficiently and reproducibly delivers the pathogen in between the plant leaves, would facilitate the rapid identification of maize lines that are resistant to U. maydis. As, a first step toward indentifying maize lines that are resistant to U. maydis, a needle injection inoculation method and a resistance reaction screening method was utilized to inoculate maize, teosinte, and maize x teosinte introgression lines with a U. maydis strain and to select resistant plants. Maize, teosinte and maize x teosinte introgression lines, consisting of about 700 plants, were planted, inoculated with a strain of U. maydis, and screened for resistance. The inoculation and screening methods successfully identified three teosinte lines resistant to U. maydis. Here a detailed needle injection inoculation and resistance reaction screening protocol for maize, teosinte, and maize x teosinte introgression lines is presented. This study demonstrates that needle injection inoculation is an invaluable tool in agriculture that can efficiently deliver U. maydis in between the plant leaves and has provided plant lines that are resistant to U. maydis that can now be combined and tested in breeding programs for improved disease resistance.

  13. Nitrate leaching from Silage Maize

    OpenAIRE

    Hansen, Elly Møller; Eriksen, Jørgen

    2009-01-01

    During the last 20 years the area with maize in Denmark has increased dramatically and reached 163,000 ha in 2008. Silage maize is easy to grow, is a suitable fodder for cows and goes well with grass-clover in the diet. This means that silage maize is often found in crop rotations with grass-clover on sandy soils in western Denmark. The ploughing in of grass-clover fields poses a serious risk of increased nitrate leaching on a coarse sandy soil, even when carried out in spring. With increased...

  14. Chitosan adsorption to salivary pellicles

    NARCIS (Netherlands)

    van der Mei, Henderina; Engels, Eefje; de Vries, Jacob; Dijkstra, Rene JB; Busscher, Hendrik

    2007-01-01

    The salivary pellicle is a negatively charged protein film, to which oral bacteria readily adhere. Chitosans are cationic biomolecules with known antimicrobial properties that can be modified in different ways to enhance its antimicrobial activity. Here, we determined the changes in surface chemical

  15. The influence of feeding crimped kernel maize silage on broiler production, nutrient digestibility and meat quality

    DEFF Research Database (Denmark)

    Ranjitkar, Samir; Karlsson, Anders H.; Petersen, Mikael A.

    2016-01-01

    1. Two experiments were carried out in parallel with male Ross 308 broilers over 37 d. An experiment with a total of 736 broilers was performed to study the effect of dietary inclusion of crimped kernel maize silage (CKMS) on broiler production and meat quality. Another study with 32 broilers...... was carried out from 21-25 d to investigate the inclusion of CKMS on nutrient digestibility. 2. In both trials, 4 dietary treatments were used: wheat based feed (WBF), maize based feed (MBF), maize based feed supplemented with 15% CKMS (CKMS-15) and maize based feed supplemented with 30% CKMS (CKMS-30). 3....... Broiler mortality decreased significantly when CKMS was added to the diet. 5. The consumption of drinking water was significantly lower in all maize based diets as compared to WBF and was lowest in broilers fed CKMS-30. 6. An improved litter quality in terms of dry matter content and a lower frequency...

  16. The Optical Absorption Coefficient of Maize Grains Investigated by Photoacoustic Spectroscopy

    Science.gov (United States)

    Rodríguez-Páez, C. L.; Carballo-Carballo, A.; Rico-Molina, R.; Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Moreno-Martínez, E.

    2017-01-01

    In the maize and tortilla industry, it is important to characterize the color of maize ( Zea mays L.) grain, as it is one of the attributes that directly affect the quality of the tortillas consumed by the population. For this reason, the availability of alternative techniques for assessing and improving the quality of grain is valued. Photoacoustic spectroscopy has proven to be a useful tool for characterizing maize grain. So, the objective of the present study was to determine the optical absorption coefficient β of the maize grain used to make tortillas from two regions of Mexico: (a) Valles Altos, 2012-2013 production cycle and (b) Guasave, Sinaloa, 2013-2014 production cycle. Traditional reflectance measurements, physical characteristics of the grain and nutrient content were also calculated. The experimental results show different characteristics for maize grains.

  17. Preparation and Application of Chitosan Membranes to Filter Silver from X-ray Film Processing Wastes

    Science.gov (United States)

    Nyoman Rupiasih, N.; Rustam Purnomo, Rendra; Sumadiyasa, Made

    2016-04-01

    Chitosan is a natural polysaccharide biopolymer which has been widely used in different processes and applications. Chitosan based membranes have been used in reverse osmosis, gas separation, dialysis and pervaporation. The object of this research was investigating the possibility of chitosan membrane used as a filter for removing silver (Ag) from X-ray film processing wastes. Several of chitosan membranes such as M1, M2, M3 and M4 have been prepared for the purpose and filtration was done using dead-end filtration method. The filtration experiments were performed on a flat sheet membrane using pure water and X-ray film processing wastes as feeds. The analysis of silver concentration has been done by atomic absorption spectrometers (AAS). The results show that chitosan membrane M2 gave the highest filtration coefficient (Rcoeff ) i.e. 99.9%, with the pure water flux (PWF) and product flux (PF) are 2972.56 L/m2h and 1761.18 L/m2h respectively. The rejection coefficient of the membranes decreases with increasing the amount of chitosan, while the pure water flux and product flux are increased. The filtration coefficients show that the chitosan membranes are able to filter silver waste from X-ray film processing wastes with performance dependent on their characteristic such as pores size. This suggests that, chitosan membrane can be used as one method that is safe and friendly environment for recovering silver from X-ray film processing waste to improve the quality of treated to an acceptable quality level.

  18. Chitosan-praseodymium complex for adsorption of fluoride ions from water

    Institute of Scientific and Technical Information of China (English)

    Eny Kusrini; Nofrijon Sofyan; Nyoman Suwartha; Gefin Yesya; Cindy Rianti Priadi

    2015-01-01

    Engineering of chitosan by praseodymium has been investigated to improve the adsorption properties as well as physical characteristics of chitosan. Modification of chitosan changes the original properties of chitosan so that it can be more suitable for ad-sorption of fluoride ions. In this study, chitosan-praseodymium (Chi-Pr) was synthesized by impregnation method. The Chi-Pr com-plex was characterized by scanning electron microscopic-energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform in-frared (FTIR) and employed as an adsorbent for removal of fluorides ions from water in the batch system. The variables such as con-tact time, concentration of Pr, adsorbent dose, initial concentration of fluoride ions, and competitor anions were studied. The adsorp-tion efficiency of fluoride ions (η) with increasing Pr loading into chitosan (5 wt.%, 10 wt.%, 15 wt.%, 20 wt.% and 25 wt.%) were 35.5%, 56.1%, 72.0%, 68.5% and 62.5%, respectively. The Chi-Pr (15 wt.%) complex had the highest fluoride removal efficiency (72.0%). The experimental data fitted well to the Langmuir isotherm with maximum adsorption capacity (qmax) of 15.87 mg/g and an equilibrium constant (kL) of 0.15 mg. Kinetic study revealed that the adsorption of fluoride ions from water followed pseudo-second-order model with a maximum adsorption capacity (q2) of 8.20 mg/g and a rate constant (k2) of 0.01 g/mg·min. Ad-sorption efficiency of fluoride ions in the simulated drinking water was diminished with the changes in pH levels. The presence of Pr3+in chitosan increased chitosan's performance as an adsorbent for adsorption of fluoride ions.

  19. A high throughput method for quantification of cell surface bound and internalized chitosan nanoparticles.

    Science.gov (United States)

    Tammam, Salma N; Azzazy, Hassan M E; Lamprecht, Alf

    2015-11-01

    Chitosan has become a popular polymer for drug delivery. It's hydro solubility and mild formulation conditions have made it an attractive polymer for macromolecular delivery. Accurate quantification of internalized chitosan nanoparticles (NPs) is imperative for fair assessment of the nano-formulation where it is important to determine the exact amount of drug actually being delivered into the cell, especially for macromolecular drugs where cellular entry is limited by molecule size and/or charge. The preferential affinity of wheat germ agglutinin tagged with fluorescein isothiocyanate (WGA-FITC) to chitosan is exploited in the development of a simple and rapid method for the differentiation between and quantification of cell surface bound and internalized chitosan NPs. The percentage of cell surface bound NPs could be easily determined and corrected NP uptake could be calculated accordingly. The developed method is applicable in several cell lines and has successfully been tested with NPs with different sizes (25 and 150nm) and with very low NP concentrations (20μg/mL). The method will allow for the correct evaluation of chitosan NP uptake and could be further used to evaluate chitosan based nanomedicine and provide guidelines on how to modify NPs for enhanced internalization, and improved drug delivery.

  20. Fabrication, nanomechanical characterization, and cytocompatibility of gold-reinforced chitosan bio-nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Nimitt G. [Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, 13699 (United States); Materials Science and Engineering PhD Program, Clarkson University, Potsdam, NY, 13699 (United States); Kumar, Ajeet [Center for Advanced Materials Processing, Clarkson University, Potsdam, NY, 13699 (United States); Jayawardana, Veroni N. [Department of Mathematics, Clarkson University, Potsdam, NY, 13699 (United States); Woodworth, Craig D. [Department of Biology, Clarkson University, Potsdam, NY, 13699 (United States); Yuya, Philip A., E-mail: pyuya@clarkson.edu [Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, 13699 (United States)

    2014-11-01

    Chitosan, a naturally derived polymer represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Gold nanoparticles (∼ 32 nm) were synthesized via a citrate reduction method from chloroauric acid and incorporated in Chitosan matrix. Bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through solution casting process. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed with SEM. Synthesis outcomes and prepared nanocomposites were characterized using SEM, TEM, EDX, SAED, UV–vis, XRD, DLS, and Zeta potential for their physical, morphological and structural properties. Nanoscale properties of materials under the influence of temperature were characterized through nanoindentation techniques. From quasi-static nanoindentation, it was observed that hardness and reduced modulus of the nanocomposites were increased significantly in direct proportion to the gold nanoparticle concentration. Gold nanoparticle concentration also showed positive impact on storage modulus and thermal stability of the material. The obtained films were confirmed to be biocompatible by their ability to support growth of human cells in vitro. In summary, the results show enhanced mechanical properties with increasing gold nanoparticle concentration, and provide better understanding of the structure–property relationships of such biocompatible materials for potential biomedical applications. - Highlights: • We fabricated gold reinforced chitosan nanocomposite for biomedical applications. • Gold nanoparticles significantly enhanced nanomechanical properties of chitosan. • Nanocomposite films supported growth of human cells in vitro. • Gold nanoparticles significantly improved cell proliferation on chitosan films.

  1. In vitro and in vivo Characterization of Homogeneous Chitosan-based Composite Scaffolds

    Institute of Scientific and Technical Information of China (English)

    LI Hong; ZHOU Changren; ZHU Minying; TIAN Jinhuan; RONG Jianhua

    2012-01-01

    With a homogeneous distribution of hydroxyapatite (HAP) crystals in polymer matrix,composite scaffolds chitosan/HAP and chitosan/collagen/HAP were fabricated in the study.XRD,SEM and EDX were used to characterize their components and structure,in vitro cell culture and in vivo animal tests were used to evaluate their biocompatibility.HAP crystals with rod-like shape embeded in chitosan scaffold,while HAP fine-granules bond with collagen/chitosan scaffold compactly.A homogenous distribution of Ca and P elements both in chitosan/HAP scaffold and chitosan/collagen/HAP scaffold was defined by EDX pattern.The presence of collagen brought a more homogenous distribution of HAP due to its higher ability to induce HAP precipitation.The results of in vitro cell culture showed that the composite's biocompatibility was enhanced by the homogenous distribution of HAP.In vivo animal studies showed that the in vivo biodegradation was effectively improved by the addition of HAP and collagen,and was less influenced by the homogeneous distribution of HAP when compared with a concentrated distribution one.The composite scaffolds with a homogeneous HAP distribution would be excellent alternative scaffolds for bone tissue engineering.

  2. In vitro corrosion behavior and cytotoxicity property of magnesium matrix composite with chitosan coating

    Institute of Scientific and Technical Information of China (English)

    戴翌龙; 余琨; 陈良建; 陈畅; 乔雪岩; 颜阳

    2015-01-01

    Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 composite, such as the adhesion ability, the corrosion behavior and the cytotoxicity properties, were investigated, and the microstructure of the chitosan coating was observed by scanning electron microscope (SEM). The results show that chitosan coating improves the corrosion resistance of the magnesium composite specimens significantly. Mg-6%Zn-10%β-Ca3(PO4)2 composite specimens exhibit good corrosion resistance and low pH values in simulated body fluid (SBF) at 37 °C in the immersion test with 7-layer chitosan coating whose relative molecular mass is 30×104 Da. The cytotoxicity tests indicate that Mg-6%Zn-10%β-Ca3(PO4)2 with chitosan coating is nontoxic with a cytotoxicity grade of zero against L-929 cells, which is better than that of uncoated composites.

  3. Chitosan use in chemical conditioning for dewatering municipal-activated sludge.

    Science.gov (United States)

    Zemmouri, H; Mameri, N; Lounici, H

    2015-01-01

    This work aims to evaluate the potential use of chitosan as an eco-friendly flocculant in chemical conditioning of municipal-activated sludge. Chitosan effectiveness was compared with synthetic cationic polyelectrolyte Sedipur CF802 (Sed CF802) and ferric chloride (FeCl₃). In this context, raw sludge samples from Beni-Messous wastewater treatment plant (WWTP) were tested. The classic jar test method was used to condition sludge samples. Capillary suction time (CST), specific resistance to filtration (SRF), cakes dry solid content and filtrate turbidity were analyzed to determine filterability, dewatering capacity of conditioned sludge and the optimum dose of each conditioner. Data exhibit that chitosan, FeCl₃and Sed CF802 improve sludge dewatering. Optimum dosages of chitosan, Sed CF802 and FeCl₃allowing CST values of 6, 5 and 9 s, were found, respectively, between 2-3, 1.5-3 and 6 kg/t ds. Both polymers have shown faster water removal with more permeable sludge. SRF values were 0.634 × 10¹², 0.932 × 10¹² and 2 × 10¹² m/kg for Sed CF802, chitosan and FeCl₃respectively. A reduction of 94.68 and 87.85% of the filtrate turbidity was obtained with optimal dosage of chitosan and Sed CF802, respectively. In contrast, 54.18% of turbidity abatement has been obtained using optimal dosage of FeCl₃.

  4. Effects of hydrophobic and hydrophilic modifications on gene delivery of amphiphilic chitosan based nanocarriers.

    Science.gov (United States)

    Wang, Bingqing; He, Chunbai; Tang, Cui; Yin, Chunhua

    2011-07-01

    The structure-activity relationships between hydrophobic and hydrophilic modification on chitosan and resultant physicochemical properties along with performances in dealing with critical gene delivery barriers were investigated through amphiphilic linoleic acid(LA) and poly (β-malic acid) (PMLA) double grafted chitosan (LMC)/plasmid DNA (pDNA) nanocomplexes. LMC polymers with various LA and PMLA substitution degrees were synthesized and their hydrophilicity/hydrophobicity was characterized. Compared to chitosan, LMC nanoparticles retained the pDNA binding ability at pH 5.5 when they formed nanocomplexes with pDNA encoding enhanced green fluorescence protein (pEGFP) and the resultant complexes showed diameters below 300 nm. Hydrophobic LA and hydrophilic PMLA substitution contributed to suppressed non-specific adsorption, reduced interactions inside LMC/pDNA nanocomplexes, and enhanced pDNA dissociation. However, enzymatic degradation resistance, cell adsorption, and cellular uptake through clathrin-mediated pathway were promoted by hydrophobic LA grafting while being inhibited by hydrophilic PMLA substitution. In vitro transfection assay suggested the optimal LMC/pEGFP nanocomplexes mediated an 8.0-fold improved transfection compared to chitosan/pEGFP nanocomplexes. The 4.2-fold and 2.2-fold higher intramuscular gene expression in mice compared to chitosan/pEGFP and polyethyleneimine (PEI)/pEGFP nanocomplexes further demonstrated the superiority of LMC/pDNA nanocomplexes. Therefore, amphiphilic chitosan derivates with appropriate combination of hydrophobic and hydrophilic modification would be promising gene delivery nanocarriers.

  5. Iron casein succinylate-chitosan coacervate for the liquid oral delivery of iron with bioavailability and stability enhancement.

    Science.gov (United States)

    Min, Kyoung Ah; Cho, Jung-Hye; Song, Yun-Kyoung; Kim, Chong-Kook

    2016-01-01

    Iron casein succinylate (ICS) liquid oral preparation as iron supplement has uncomfortable taste after a long period of storage because of its stability, and poor bioavailability of iron compared to any other iron preparations. To improve the chemical stability of ICS and enhance the bioavailability of iron, chitosan-ICS nanoparticles (NPs) were prepared by complex coacervation method and stabilized with polyethylene glycol (PEG) 400. NPs were spherical (mean diameter of 830-1070 nm) with positive charge (+30-60 mV) depending on the composition of NPs. Addition of PEG400 (2 w/v %) increased the zeta potential (26-50 %) and physical stability of chitosan-ICS NPs suspension. Also, NPs decreased iron release compared to ICS after 7-weeks of storage at 4 °C. NPs markedly increased the permeability of iron in Caco-2 cell up to 32-38-fold compared to ICS, while physical mixture of chitosan and ICS increased the iron permeability only 2.5-fold. In summary, NPs improved the physicochemical stability and enhanced the transport of iron compared to other iron preparations in Caco-2 cell model. Thus, chitosan-ICS coacervate might be a promising candidate as a liquid oral iron delivery system for iron deficiency patients with stability and bioavailability enhancement.

  6. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    Directory of Open Access Journals (Sweden)

    Pajić Zorica

    2007-01-01

    Full Text Available Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection.

  7. Chitosan Modification and Pharmaceutical/Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Jiali Zhang

    2010-06-01

    Full Text Available Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1 enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2 the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3 synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy.

  8. A GREEN APPLICATION OF NANO SIZED CHITOSAN IN TEXTILE FINISHING

    OpenAIRE

    ŞAHAN, Görkem; DEMİR, Aslı

    2016-01-01

    Wool fabrics are subjected to different surface modification methods in order to improve their hydrophilicity, dyeability, antimicrobial, shrinkproofing properties. Especially environmental friendly methods and application of biopolymers are gaining importance instead of conventional processes and textile chemicals. In this study, nanochitosan particles were synthesized, applied on wool fabrics and compared with bulk chitosan in terms of various properties. Ag-loade...

  9. New crosslinkers for electrospun chitosan fibre mats. I. Chemical analysis

    OpenAIRE

    Austero, Marjorie S.; Donius, Amalie E.; Wegst, Ulrike G.K.; Schauer, Caroline L.

    2012-01-01

    Chitosan (CS), the deacetylated form of chitin, the second most abundant, natural polysaccharide, is attractive for applications in the biomedical field because of its biocompatibility and resorption rates, which are higher than chitin. Crosslinking improves chemical and mechanical stability of CS. Here, we report the successful utilization of a new set of crosslinkers for electrospun CS. Genipin, hexamethylene-1,6-diaminocarboxysulphonate (HDACS) and epichlorohydrin (ECH) have not been previ...

  10. Preparation and characterization of crosslinked chitosan-based nanofibers

    Institute of Scientific and Technical Information of China (English)

    Ying Shan Zhou; Dong Zhi Yang; Jun Nie

    2007-01-01

    Crosslinked chitosan-based nanofibers were successfully prepared via electrospinning technique with heat mediated chemical crosslinking followed. The structure, morphology and mechanical property of nanofibers were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), Instron machine, respectively. The results showed that, nanofibers exhibited a smooth surface and regular morphology, and tensile strength of nanofibers improved with increasing of triethylene glycol dimethacrylate (TEGDMA) content.

  11. In Vitro Degradation of Polyglycolide/Chitosan Hybrid Braids

    Institute of Scientific and Technical Information of China (English)

    YUAN Xiaoyan; ZHANG Qingwei; WANG Yonglin; YAO Kangde

    2005-01-01

    Hybrid braids of polyglycolide (PGA) and chitosan were prepared by the three-yarn braiding method from PGA and chitosan fiber bundles. These braids were in vitro degraded by incubating them in phosphate buffered saline (PBS) at pH 7.4 and 37 ℃ for 5 weeks. Results suggested that PGA/chitosan hybrid braids degraded significantly. Scanning electron micrographs showed that chitosan fibers in the PGA/chitosan hybrid braid with about 750% PGA in weight (PGA75/chitosan) were shaped into gel-like after 5 weeks, but those in the hybrid braid with about 250% PGA in weight (PGA25/chitosan) did not change. After 5 weeks, the ultimate tensile loads of PGA and PGA75/chitosan braids lost almost completely, but those of chitosan and PGA25/chitosan braids remained around 14 N. The PGA/chitosan hybrid braids with higher initial ultimate tensile load would have potential applications in tendon/ligament tissue reconstruction.

  12. Introducing Bt Gene Into Maize With Ovary Injection

    Institute of Scientific and Technical Information of China (English)

    丁群星; 谢友菊; 戴景瑞; 米景九; 李太元; 田颖川; 乔利亚; 莽克强; 刘宝兰; 王音; 冯平章

    1994-01-01

    It is reported here that Bt toxin gene has been successfully transferred into maize inbred line by ovary injection for the first time both at home and abroad. One transgenic plant (To) has been confirmed by Southern blotting and PCR test, and 71 progenies (T1) from T0 have been obtained through self-pollination. Of these 71 progenies, seven plants demonstrated positive results in the PCR test; four were used to feed Asian corn borer, and certain effect of insect-resistance was observed. The experiments on the ovary injection in Hainan Province have also been repeated, thus providing new chance to the application of genetic engineering to the maize improvement.

  13. ADSORPTION OF LDL ON THE MODIFIED CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    LIUManying; ZHAOLirui; 等

    2000-01-01

    In this paper,the selective adsorption of LDL on chitosan modified with PEG and Asp.was studied.The adsorption rate of LDL and HDL on the double modified chitosan was 57% and 12% respoectively,The results shown that the double modified chitosan can be used a adsorbent for selective binding to LDL,this work may help to develop functional columns for hemoperfusion.

  14. Agrobacterium-mediated transformation of maize (Zea mays) immature embryos.

    Science.gov (United States)

    Lee, Hyeyoung; Zhang, Zhanyuan J

    2014-01-01

    Agrobacterium tumefaciens-mediated transformation is one of the most efficient and simple gene delivery systems for genetic improvement and biology studies in maize. This system has become more widely used by both public and private laboratories. However, transformation efficiencies vary greatly from laboratory to laboratory for the same genotype. Here, we illustrate our advanced Agrobacterium-mediated transformation method in Hi-II maize using simple binary vectors. The protocol utilizes immature embryos as starting explants and the bar gene as a selectable marker coupled with bialaphos as a selective agent. The protocol offers efficient transformation results with high reproducibility, provided that some experimental conditions are well controlled. This transformation method, with minor modifications, can be also employed to transform certain maize inbreds.

  15. Alkylation of Chitosan as Nerve Conduit Biomaterial

    Institute of Scientific and Technical Information of China (English)

    邓劲光; 公衍道; 程明愚; 赵南明; 张秀芳

    2002-01-01

    Chitosan under physiological conditions is a degradable and biocompatible biomaterial with a wide variety of useful physicochemical properties. However, as a nerve conduit biomaterial, its solubility was very low, so chitosan was modified chemically to enhance its solubility. The free amino groups of long molecular chains in chitosan are responsible for its solubility, and the solubility could be adjusted by controlling the free amidogen capacity with N-alkylation. The results show that the solubility of N-alkylation chitosan is increased to 10%, which is an increase of 500%.

  16. Characterization of multilayered and composite edible films from chitosan and beeswax.

    Science.gov (United States)

    Velickova, Elena; Winkelhausen, Eleonora; Kuzmanova, Slobodanka; Moldão-Martins, Margarida; Alves, Vitor D

    2015-03-01

    Chitosan-based edible films were prepared and subjected to cross-linking reactions using sodium tripolyphosphate and/or to beeswax coating on both films interfaces. In addition, chitosan-beeswax emulsion-based films were produced. The goal of these modifications of the chitosan films was the improvement of their barrier to water vapor and to decrease their affinity to liquid water maintaining or improving the mechanical and optical properties of the original chitosan films. The cross-linking with tripolyphosphate decreased both the water vapor permeability and the water absorption capacity to about 55% and 50% of that of the original chitosan films, respectively. However, there was an increase in the films stiffness, revealed by the increased Young modulus from 42 kPa up to 336 kPa. The multilayered wax-chitosan-wax films exhibited a similar improvement of the barrier properties to water vapor, with the advantage of maintaining the mechanical properties of the original chitosan films. However, these wax-coated films showed a higher water absorption capacity, which is believed to be a consequence of water entry into small pores between the film and the wax layers. Regarding the film samples subjected to cross-linking and further coating with beeswax, a similar behavior as the uncoated cross-linked films was observed. The emulsion-based composite films were characterized by a substantial decrease of the water vapor permeability (40%), along with a decrease in their stiffness. Regarding the optical properties, all films presented a yellowish color with similar values of lightness, chroma, and hue.

  17. Sequencing the maize genome.

    Science.gov (United States)

    Martienssen, Robert A; Rabinowicz, Pablo D; O'Shaughnessy, Andrew; McCombie, W Richard

    2004-04-01

    Sequencing of complex genomes can be accomplished by enriching shotgun libraries for genes. In maize, gene-enrichment by copy-number normalization (high C(0)t) and methylation filtration (MF) have been used to generate up to two-fold coverage of the gene-space with less than 1 million sequencing reads. Simulations using sequenced bacterial artificial chromosome (BAC) clones predict that 5x coverage of gene-rich regions, accompanied by less than 1x coverage of subclones from BAC contigs, will generate high-quality mapped sequence that meets the needs of geneticists while accommodating unusually high levels of structural polymorphism. By sequencing several inbred strains, we propose a strategy for capturing this polymorphism to investigate hybrid vigor or heterosis.

  18. 中南穿梭育种对南斯拉夫玉米群体改良的互补性研究%The Mutual Complement Studies for Yugoslavia Maize Population Improvement Through the Shuttle Breeding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    1985-1997年对南斯拉夫玉米群体SYN1/9 C0进行半同胞轮回选择。1998年通过把在唐山C1~C6和在贝尔格莱德进行C3~C6共计10个轮回群体与4个标准自交系进行半双列杂交研究,连续2年试验,结果一致。研究结果表明对群体产量和测交组合产量以及产量杂种优势、配合力和田间部分性状一般配合力均存在显著差异,南斯拉夫和唐山两地改良效果极具互补性。实验表明,中南穿梭育种在提高南斯拉夫群体自身产量、测交组合产量的同时,能更为有效地提升群体杂种优势,使产量特殊配合力、一般配合力同时提高。%Yugoslavia maize population improvement was carried out by the method of HSRS and the way of shuttle beeding during 1985 to 1997。The 10 circles including 6 circles achieved in TangShang and 3 circles done in Belgrade were crossed with 4 inbred lined in half dialled-cross。40 hybrids together with 10 circles and 4 inbred lines were planted and studied for 2 years in TangShan。Signifficant difference and Strong complement were discovered,such as population yield and average yield of top-tested crosses。planting traits GCA and heterosis。The studied results also showed that shuttle breeding could improve not only population but also heterosis,especially SCA and GCA of yield were acquired。with the same steps。

  19. Characterization of Chitosan and fabrication of Chitosan hydrogels matrices for biomedical applications

    Directory of Open Access Journals (Sweden)

    Charhouf I.

    2013-09-01

    Full Text Available The development of injectable hydrogels for drug delivery is a major challenge. Chitosan is a copolymer of N-acetylglucosamine and glucosamine units and is represented as a copolymer. Chitosan occurs in nature in the cell walls of some fungi, exoskeletons of insects and marine animals such as crabs and prawns. Chitosan and its derivatives possess a wide range of useful properties. They are biodegradable, and biocompatible with antibacterial and antioxidant activities. They are useful in drug delivery formulations and tissue engineering. The objective of the present study was to characterize chitosan, prepare chitosan hydrogels and study the gelation of this hydrogels over time. Chitosan with DDA% ∼ 80%–90% were characterized by infrared spectroscopy, conductimetry and pH-metry. In addition, chitosan hydrogels were prepared using an ionic gelation method making it suitable for biomedical applications.

  20. Nanomechanical characterization and molecular mechanism study of nanoparticle reinforced and cross-linked chitosan biopolymer.

    Science.gov (United States)

    Rath, Amrita; Mathesan, Santhosh; Ghosh, Pijush

    2015-03-01

    Chitosan (CS) is a biomaterial that offers many sophisticated and innovative applications in the biomedical field owing to its excellent characteristics of biodegradability, biocompatibility and non-toxicity. However, very low mechanical properties of chitosan polymer impose restriction on its further development. Cross-linking and nanoparticle reinforcement are the two possible methods to improve the mechanical properties of chitosan films. In this research, these two methods are adopted individually by using tripolyphosphate as cross-linker and nano-hydroxyapatite as particle reinforcement. The nanomechanical characterizations under static loading conditions are performed on these modified chitosan films. It is observed that nanoparticle reinforcement provided necessary mechanical properties such as ductility and modulus. The mechanisms involved in improvement of mechanical properties due to particle reinforcement are studied by molecular dynamics (MD). Further, improvement in mechanical properties due to combination of particle reinforcement and cross-linking agent with chitosan is investigated. The stress relaxation behavior for all these types of films is characterized under dynamic loading conditions using dynamic mechanical analysis (nanoDMA) experiment. A viscoelastic solid like response is observed for all types of film with modulus relaxing by 3-6% of its initial value. A suitable generalized Maxwell model is fitted with the obtained viscoelastic response of these films. The response to nano-scratch behavior is also studied for particle reinforced composite films.

  1. Changes in plant morphology in response to recurrent selection in the Iowa Stiff Stalk synthetic maize population

    Science.gov (United States)

    The maize plant phenotype has changed a great deal through the era of hybrid maize production. Some of the observed changes, such as upright leaf angle, silking-anthsis interval, and tassel branch number, have well understood contributions to improved grain yield in modern hybrids. However, less is ...

  2. Influence of maize/lablab intercropping on lepidopterous stem borer infestation in maize.

    Science.gov (United States)

    Maluleke, Mary H; Addo-Bediako, Abraham; Ayisi, Kingsley K

    2005-04-01

    Lepidopterous stem borers seriously affect production of maize, Zea mays L., in sub-Saharan Africa. Intercropping maize with legumes such as lablab, Lablab purpurens (L.), is one of the effective systems to control stem borers. Sole culture maize and maize/lablab intercrop system of different lablab densities were planted at two locations to investigate the effects of intercrop system on incidence and severity of stem borers with particular reference to Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae). Stem borer infestation was found to be more severe in sole culture maize than maize in maize/lablab intercrop. There was a significantly negative relationship between lablab densities and maize grain yields, suggesting a possible competition for resources between the two crops. It was concluded that density of lablab and date of planting of lablab in maize/lablab intercropping have significant affects on stem borer populations and maize grain yields.

  3. Preparation of Lysine Modified Chitosan Nanoparticles%赖氨酸改性壳聚糖的制备研究

    Institute of Scientific and Technical Information of China (English)

    符思达; 沈逸敏; 陈巧玲; 朱培培; 汤汉; 王亨缇; 孙燕

    2012-01-01

    Lysine modified chitosan was prepared and characterized in the study. A series of reaction parameters, such as ratio of lysine and chitosan, were tested. The lysine grafted chitosan was characterized by fourier transform infrared spectroscopy and differential scanning calorimetry, and the water-soluable ability of lysine grafted chitosan also was tested. The results showed that lysine grafted chitosan was synthesized successfully and the optimal reaction parameters were as following: the ratio of lysine and chitosan was 3 : 1. After lysine modified, the water-soluable ability of chitosan was improved significantly.%本实验以赖氨酸改性壳聚糖为研究对象,对赖氨酸对壳聚糖的改性进行研究。改变壳聚糖与赖氨酸的质量比研究其改性效果。差示扫描量热分析、红外光谱表征以及水溶性试验表明赖氨酸改性壳聚糖是成功的。赖氨酸与壳聚糖的比例为3:1的时,改性较好。赖氨酸改性后的壳聚糖其水溶性显著提高。

  4. A mediator-free glucose biosensor based on glucose oxidase/chitosan/α-zirconium phosphate ternary biocomposite.

    Science.gov (United States)

    Liu, Li-Min; Wen, Jiwu; Liu, Lijun; He, Deyong; Kuang, Ren-yun; Shi, Taqing

    2014-01-15

    A novel glucose oxidase/chitosan/α-zirconium phosphate (GOD/chitosan/α-ZrP) ternary biocomposite was prepared by co-intercalating glucose oxidase (GOD) and chitosan into the interlayers of α-zirconium phosphate (α-ZrP) via a delamination-reassembly procedure. The results of X-ray diffraction, infrared spectroscopy, circular dichroism, and ultraviolet spectrum characterizations indicated not only the layered and hybrid structure of the GOD/chitosan/α-ZrP ternary biocomposite but also the recovered activity of the intercalated GOD improved by the co-intercalated chitosan. By depositing the GOD/chitosan/α-ZrP biocomposite film onto a glassy carbon electrode, the direct electrochemistry of the intercalated GOD was achieved with a fast electron transfer rate constant, k(s), of 7.48±3.52 s(-1). Moreover, this GOD/chitosan/α-ZrP biocomposite modified electrode exhibited a sensitive response to glucose in the linear range of 0.25-8.0 mM (R=0.9994, n=14), with a determination limit of 0.076 mM.

  5. Preparation and Characterization of Chitosan/Zinc Oxide Nanoparticles for Imparting Antimicrobial and UV Protection to Cotton Fabric

    Directory of Open Access Journals (Sweden)

    M. M. AbdElhady

    2012-01-01

    Full Text Available Synthesis of chitosan/ZnO nanoparticles was performed using different concentrations of ZnO at different temperatures. Nanoparticles of ZnO/chitosan were prepared in rod form with average length 60 nm and average width 5–15 nm. Thus, obtained nanoparticles of ZnO/chitosan were characterized using UV spectrophotometer, FTIR, TEM, X-ray, and SEM. Size and shape of chitosan/ZnO nanoparticles relied on conditions of their synthesis. Notably, chitosan/ZnO in rod form with average length of 60 nm and average width 5–15 nm could be achieved. Application of chitosan/ZnO nanoparticles to cotton fabric conferred on the latter antibacterial and UV protection properties. Cotton fabric was characterized using SEM, ultraviolet protection factor (UPF rating, and antibacterial (gram-positive and gram-negative characteristics. Finished cotton fabric exhibited good antibacterial properties against gram-positive and gram-negative bacteria. The UV testes indicated a significant improvement in UV protection of finished cotton fabric which is increasing by increasing the concentration of nanoparticles of ZnO/chitosan.

  6. Thermoresponsive chitosan-agarose hydrogel for skin regeneration.

    Science.gov (United States)

    Miguel, Sónia P; Ribeiro, Maximiano P; Brancal, Hugo; Coutinho, Paula; Correia, Ilídio J

    2014-10-13

    Healing enhancement and pain control are critical issues on wound management. So far, different wound dressings have been developed. Among them, hydrogels are the most applied. Herein, a thermoresponsive hydrogel was produced using chitosan (deacetylation degree 95%) and agarose. Hydrogel bactericidal activity, biocompatibility, morphology, porosity and wettability were characterized by confocal microscopy, MTS assay and SEM. The performance of the hydrogel in the wound healing process was evaluated through in vivo assays, during 21 days. The attained results revealed that hydrogel has a pore size (90-400 μm) compatible with cellular internalization and proliferation. A bactericidal activity was observed for hydrogels containing more than 188 μg/mL of chitosan. The improved healing and the lack of a reactive or a granulomatous inflammatory reaction in skin lesions treated with hydrogel demonstrate its suitability to be used in a near future as a wound dressing.

  7. Bioavailability of iron, zinc, folic acid, and vitamin A from fortified maize.

    Science.gov (United States)

    Moretti, Diego; Biebinger, Ralf; Bruins, Maaike J; Hoeft, Birgit; Kraemer, Klaus

    2014-04-01

    Several strategies appear suitable to improve iron and zinc bioavailability from fortified maize, and fortification per se will increase the intake of bioavailable iron and zinc. Corn masa flour or whole maize should be fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA), ferrous fumarate, or ferrous sulfate, and degermed corn flour should be fortified with ferrous sulfate or ferrous fumarate. The choice of zinc fortificant appears to have a limited impact on zinc bioavailability. Phytic acid is a major inhibitor of both iron and zinc absorption. Degermination at the mill will reduce phytic acid content, and degermed maize appears to be a suitable vehicle for iron and zinc fortification. Enzymatic phytate degradation may be a suitable home-based technique to enhance the bioavailability of iron and zinc from fortified maize. Bioavailability experiments with low phytic acid-containing maize varieties have suggested an improved zinc bioavailability compared to wild-type counterparts. The bioavailability of folic acid from maize porridge was reported to be slightly higher than from baked wheat bread. The bioavailability of vitamin A provided as encapsulated retinyl esters is generally high and is typically not strongly influenced by the food matrix, but has not been fully investigated in maize.

  8. Preparation and antibacterial activity of quaternized chitosan with iodine

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yang; Xie, Linlin; Sai, Mingze; Xu, Ningning; Ding, Derun, E-mail: dingderun@sues.edu.cn

    2015-03-01

    Chitosan (CTS) is a natural polymer with active groups such as –NH{sub 2} which can be functionalized to introduce new positively charged N-atoms and protonated amino group for better use. In this study, to improve the stability of iodine, a novel complex (CTS–CTA–I{sub 2}) was prepared by mixing N-(2-hydroxy) propyl-3-trimethylammonium chitosan chloride (CTS–CTA) with iodine in ethanol solution. The CTS–CTA–I{sub 2} was characterized by Fourier transform infrared spectra (FTIR), Ultraviolet and visible (UV–vis) spectra and thermal gravimetric analysis (TG). Besides, the interaction of iodine with CTS–CTA was also studied. The mole ratio of CTS–CTA with iodine was measured by iodometric titration method and the max mole ratio of CTS–CTA with iodine was 1:1.33. The antimicrobial activity of CTS, CTS–CTA and CTS–CTS–I{sub 2} complexes was investigated against Escherichia coli and Staphylococcus aureus and the antibacterial property of CTS–CTA–I{sub 2} was superior to CTS–CTA. - Highlights: • We prepared a novel iodine complex based on chitosan. • The CTS–CTA–I{sub 2} complex improved the stability of iodine. • The max mole ratio of CTS–CTA with iodine was 1:1.33. • The CTS–CTA–I{sub 2} complex showed significant antibacterial activity.

  9. Oxidized Xanthan Gum and Chitosan as Natural Adhesives for Cork

    Directory of Open Access Journals (Sweden)

    Diana Paiva

    2016-07-01

    Full Text Available Natural cork stopper manufacturing produces a significant amount of cork waste, which is granulated and combined with synthetic glues for use in a wide range of applications. There is a high demand for using biosourced polymers in these composite materials. In this study, xanthan gum (XG and chitosan (CS were investigated as possible natural binders for cork. Xanthan gum was oxidized at two different aldehyde contents as a strategy to improve its water resistance. This modification was studied in detail by 1H and 13C nuclear magnetic resonance (NMR, and the degree of oxidation was determined by the hydroxylamine hydrochloride titration method. The performance of the adhesives was studied by tensile tests and total soluble matter (TSM determinations. Xanthan gum showed no water resistance, contrary to oxidized xanthan gum and chitosan. It is hypothesized that the good performance of oxidized xanthan gum is due to the reaction of aldehyde groups—formed in the oxidation process—with hydroxyl groups on the cork surface during the high temperature drying. Combining oxidized xanthan gum with chitosan did not yield significant improvements.

  10. Synthesis and characterization of a novel chitosan/montmorillonite/hydroxyapatite nanocomposite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Katti, Kalpana S; Katti, Dinesh R; Dash, Rajalaxmi [Department of Civil Engineering, North Dakota State University, Fargo, ND 58105 (United States)], E-mail: Kalpana.katti@ndsu.edu

    2008-09-01

    Recently, biopolymer-based nanocomposites have been replacing synthetic polymer composites for various biomedical applications. This is often because of the biocompatible and biodegradable behavior of natural polymers. Several studies have been reported pertaining to the synthesis and characterization of chitosan(chi)/montmorillonite(MMT) and chitosan (chi)/hydroxyapatite (HAP) for tissue engineering applications. In the present work, a biopolymer-based novel nanocomposite chitosan/montmorillonite (MMT)/hydroxyapatite (HAP) was developed for biomedical applications. The composite was prepared from chitosan, unmodified MMT and HAP precipitate in aqueous media. The properties of the composites were investigated using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). Nanomechanical properties were measured using nanoindentation. Cell culture experiments were also conducted in order to ascertain the biocompatibility of the composite. The XRD results indicate that an intercalated structure was formed with an increase in d-spacing of montmorillonite. FTIR studies provide the evidence of molecular interaction among the three different constituents of the composite. AFM images show well-distributed nanoparticles in the chitosan matrix. The composites also exhibit a significant enhancement in nanomechanical property as compared to pure chitosan as well as the chi/HAP and chi/MMT composites. The TGA results indicate that an intercalated nanocomposite was formed with improved thermal properties even compared to chi/MMT composites. The results of cell culture experiments show that the composite is biocompatible and has a better cell proliferation rate compared to chi/HAP composites. This work represents the design of a novel clay-chitosan-hydroxyapatite composite with improved mechanical properties that has potential applications in bone tissue engineering.

  11. Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.

    Science.gov (United States)

    Konwar, Achyut; Kalita, Sanjeeb; Kotoky, Jibon; Chowdhury, Devasish

    2016-08-17

    We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis

  12. Cell Compound of Wound Surface After the Chitosan Membranes Application

    Directory of Open Access Journals (Sweden)

    Alexandr N. Oleshko

    2014-12-01

    Full Text Available Skin regeneration is a complex dynamic process by which restores the structure and function of the external cover. In the case of large defects of the skin allografts were the methods of choice in recent decades. The disadvantages of this therapy are the presence of pain, the appearance of scars and increased mortality. The tissue engineering methods artificial materials are widely developed in recent decades for large skin defects treatment. Chitosan is one of the most promising agents in the development of materials for the treatment of major defects of the skin. Currently, there are materials in the form of hydrogel, membranes and sponges based on chitosan, which has shown high efficacy in the treatment of wounds, both in experimental and clinical settings. Nevertheless, there is a need to find new forms and compositions based on chitosan to improve health outcomes, reduce product cost and optimizing the production of materials. The aim of this work was to study the features of skin regeneration after mechanical trauma when applying chitosan membranes at the different ages. The study of the processes of skin regeneration was carried out on 180 white laboratory rats of three age categories. All the animals were randomized into 2 series - experimental and control. After injury, the animals of control series were performed daily standard wound toilet with sterile gauze, experimental series - for the topical treatment received daily applications of experimental chitosan membranes. The animals were taken from the experiment in 1, 3, 7, 14 and 21 days, which corresponds to the terms that characterize the main stages of the process of skin regeneration. We used scraping by "surface biopsy" method as well as skin imprint to get a full picture of the cellular composition of the surface defect. The use of chitosan films in the management of mechanical trauma to the skin helps to optimize intercellular cooperation, reduce the severity of inflammatory

  13. Topical formulations and wound healing applications of chitosan.

    Science.gov (United States)

    Ueno, H; Mori, T; Fujinaga, T

    2001-11-05

    Chitosan is being used as a wound-healing accelerator in veterinary medicine. To our knowledge, chitosan enhances the functions of inflammatory cells such as polymorphonuclear leukocytes (PMN) (phagocytosis, production of osteopontin and leukotriene B4), macrophages (phagocytosis, production of interleukin (IL)-1, transforming growth factor beta 1 and platelet derived growth factor), and fibroblasts (production of IL-8). As a result, chitosan promotes granulation and organization, therefore chitosan is beneficial for the large open wounds of animals. However, there are some reported complications of chitosan application. Firstly, chitosan causes lethal pneumonia in dogs which are given a high dose of chitosan. In spite of application of chitosan to various species, this finding is observed only in dogs. Secondly, intratumor injection of chitosan on mice bearing tumor increases the rate of metastasis and tumor growth. Therefore, it is important to consider these effects of chitosan, prior to drug delivery.

  14. Effect of chitosan content on gel content of epoxized natural rubber grafted with chitosan in latex form.

    Science.gov (United States)

    Riyajan, Sa-Ad; Sukhlaaied, Wattana

    2013-04-01

    The epoxidized natural rubber (ENR) latex-g-chitosan (ENR-g-chitosan) was prepared in latex form using potassium persulphate as an initiator. Firstly, the reduction in molecular weight of chitosan was subjected to the addition of K2S2O8 at 70 °C for 15 min. The structure of the modified chitosan was characterized by ATR-FTIR. Secondarily, the influence of chitosan contents, reaction time, and temperature and K2S2O8 concentrations on the gel content of the modified ENR was investigated. The chemical structure of the ENR-g-chitosan was confirmed by (1)H-NMR and ATR-FTIR. The ether linkage of the ENR-g-chitosan was conformed at 1154 an 1089 cm(-1) by ATR-FTIR and 3.60 ppm by (1)H-NMR. The gel content of ENR-g-chitosan at 5% chitosan showed the highest value compared with other samples. But when chitosan increased from 5% to 10% or 20%, the gel content of ENR-g-chitosan dramatically decreased. The ENR-g-chitosan showed good thermal resistance due to incorporation of chitosan. The morphology of ENR-g-chitosan particle showed the core-shell structure observed by TEM. The optimum condition of grafting ENR with chitosan was found at 65°C for 3h of reaction time, ratio of ENR/chitosan at 9:1.

  15. The Role of Nitrogen and Sulfur Interaction in Maize Quality(Zea mays L. )

    Institute of Scientific and Technical Information of China (English)

    XIE Rui-zhi; DONG Shu-ting; HU Chang-hao; WANG Kong-jun

    2003-01-01

    Two hybrids of maize with different responses to sulfur were used in the pool experiment. Theeffects of nitrogen and sulfur on the grain quality of maize were evaluated. The results indicated that grainquality changed with the nutrition supply. The contents of proteins, amino acids, soluble sugar, crude fat,But the effects of nitrogen and sulfur were not the same. Nitrogen increased starch content of the grain, but Sdecreased the content. Both N and S enhanced the proportion of amylopectin in starch. Sulfur nutrition signif-icantly improved the grain quality of maize when a large amount of nitrogen was used together. Both hybridshad similar response to N and S treatments.

  16. Zearalenone contamination in farm maize silage

    OpenAIRE

    L. Cavallarin; Antoniazzi, S.; E. Tabacco; G. Borreani

    2010-01-01

    Whole-plant maize silage, stored in horizontal silos, is the main diet source of lactating dairy cows in Italy. Mycotoxin contamination of maize grain has widely been described (Hussein and Brasel, 2001), while limited information is available on mycotoxins in maize silage (Oldenburg, 1991).

  17. Preparation and Characterization of Chitosan/Poly(Vinyl Alcohol Blended Films: Mechanical, Thermal and Surface Investigations

    Directory of Open Access Journals (Sweden)

    Esam A. El-Hefian

    2011-01-01

    Full Text Available In this study, blends of chitosan (CS and polyvinyl alcohol (PVA (CS/PVA having various proportions were prepared and characterized by universal mechanical tester, the differential scanning calorimetry (DSC and contact angle measurements. Studying the mechanical properties of the films showed that blending improved the tensile strength, which increased with increasing PVA content up to 40% while the elongation% at break of the blends was decreased compared to that of the pure components. The obtained results of DSC suggested that some interaction between chitosan and PVA mostly took place. Static water contact angle measurements showed an improvement in the wettability of the obtained films.

  18. Poly(N-isopropylacrylamide) surface-grafted chitosan membranes as a new substrate for cell sheet engineering and manipulation.

    Science.gov (United States)

    da Silva, Ricardo M P; López-Pérez, Paula M; Elvira, Carlos; Mano, João F; Román, Julio San; Reis, Rui L

    2008-12-15

    The immobilization of poly(N-isopropylacrylamide) (PNIPAAm) on chitosan membranes was performed in order to render membranes with thermo-responsive surface properties. The aim was to create membranes suitable for cell culture and in which confluent cell sheets can be recovered by simply lowering the temperature. The chitosan membranes were immersed in a solution of the monomer that was polymerized via radical initiation. The composition of the polymerization reaction solvent, which was a mixture of a chitosan non-solvent (isopropanol) and a solvent (water), provided a tight control over the chitosan membranes swelling capability. The different swelling ratio, obtained at different solvent composition of the reaction mixture, drives simultaneously the monomer solubility and diffusion into the polymeric matrix, the polymerization reaction rate, as well as the eventual chain transfer to the side substituents of the pyranosyl groups of chitosan. A combined analysis of the modified membranes chemistry by proton nuclear magnetic resonance ((1)H-NMR), Fourier transform spectroscopy with attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) showed that it was possible to control the chitosan modification yield and depth in the solvent composition range between 75% and 100% of isopropanol. Plasma treatment was also applied to the original chitosan membranes in order to improve cell adhesion and proliferation. Chitosan membranes, which had been previously subjected to oxygen plasma treatment, were then modified by means of the previously described methodology. A human fetal lung fibroblast cell line was cultured until confluence on the plasma-treated thermo-responsive chitosan membranes and cell sheets were harvested lowering the temperature.

  19. Multifaceted Applications of Chitosan in Cancer Drug Delivery and Therapy

    Directory of Open Access Journals (Sweden)

    Anish Babu

    2017-03-01

    Full Text Available Chitosan is a versatile polysaccharide of biological origin. Due to the biocompatible and biodegradable nature of chitosan, it is intensively utilized in biomedical applications in scaffold engineering as an absorption enhancer, and for bioactive and controlled drug release. In cancer therapy, chitosan has multifaceted applications, such as assisting in gene delivery and chemotherapeutic delivery, and as an immunoadjuvant for vaccines. The present review highlights the recent applications of chitosan and chitosan derivatives in cancer therapy.

  20. Preparation and Blood Compatibility of Oxidized-chitosan Films

    Institute of Scientific and Technical Information of China (English)

    Yue Dong YANG; Jiu Gao YU; Yong Guo ZHOU; Pei Guo LI

    2005-01-01

    Chitosan membrane was modified by the selective oxidization of chitosan molecules on its surface with NO2 gas. FTIR spectra indicated there were plenty of-COOH and -COO- groups on the modified membrane surface. The SEM study showed the modified membrane surface was rough rather than smooth as chitosan membrane. All antithrombosis test, hemolysis test and blood cell morphology observation with SEM revealed that modified chitosan membranes have superior blood compatibility to chitosan.

  1. Pengaruh Konsentrasi Antitranspiran Chitosan Terhadap Pembuahan dan Produksi Salak Gula Pasir di Luar Musim

    Directory of Open Access Journals (Sweden)

    I KETUT SUNARKA

    2016-01-01

    Full Text Available The Effect of Antitranspirant Chitosan Consentrantions to Fruit-Set and Production ff Salacca zalacca var. Gula Pasir on Off-Season. Salak Gula Pasir (Salacca zalacca var. Gula Pasir naturally flowering once every three months or four times a year. During the four times flowering, the best harvest or fruit production only once a year while the other three flowering are failed become a fruit-set. The failure was caused by rainfall and low rainy time. This research aimed to know the effect of several Antitranspirant Chitosan Consentrations to the success of flower to become a fruit (fruit-set on Salacca zalacca var. Gula Pasir. This research used random sampling where the area was divided into four Antitranspirant Chitosan Consentrations. The factor of Antitranspirant Chitosan Consentrations consists of four levels (0%, 15%, 30%, and 45%. The research was conducted at the central production of Salacca zalacca var. Gula Pasir in Sibetan Village, Bebandem District, Karangasem Regency. The result of giving Antitranspirant Chitosan Consentrations at 45% was effective improved the success of flower to become a fruit-set of 64,48% on Gadu Season while on Sela II Season it effective improved 84,38% at the 30% consentrations.

  2. Preparation and Adsorption Ability of Polysulfone Microcapsules Containing Modified Chitosan Gel

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; LUO Guangsheng; YANG Weiwei; WANG Yujun

    2005-01-01

    Chemically modified chitosan beads containing polyethyleneimine (PEI) were prepared to improve the metal ion adsorption capacity of the chitosan beads and their mechanical stability and to limit their biodegradability. The modified beads were encapsulated with the polymer material polysulfone by a novel surface coating method named the emulsion phase inversion method. The adsorption properties of the modified beads and the microstructures of the polysulfone coating layer were then analyzed. The experimental results showed that the PEI was successfully linked onto the chitosan beads. The density of the -NH2 groups in the modified beads was significantly increased, while the water content was reduced. The coating layer thickness was about 200 (m. The modified chitosan gel beads had excellent Cu(II) adsorption capacity, with a maximum Cu(II) adsorption capacity 1.34 times higher than that of the unmodified beads. The results show that even with the polysulfone coating the adsorption kinetics of the modified beads is still better than those of the unmodified beads. The modifications improve the mass transfer performance of the chitosan beads as well as the bead stability.

  3. [Adsorption behaviors of protonation modified chitosan and the analysis of spectra].

    Science.gov (United States)

    Guo, Ying-Juan; Xue, Juan-Qin; Zhang, Jie; Ma, Jing; Quan, Xue-Ting; Liu, Yao

    2014-01-01

    In order to improve adsorbing performance and stability of chitosan in acid simultaneously, cross-linking was employed after the protection of amino groups for improving its stability, then the protection of amino groups was removed and protonated to obtain high adsorption performance. With formaldehyde as amino-group protective agent and glutaraldehyde as cross-linking reagent, cross-linked chitosan (CCTS) was prepared by reversed phase suspension method in this paper, then it was protonated to make protonation modified chitosan adsorbent (P-CCTS). The adsorption performance of sulfate ion onto P-CCTS was firstly studied and investigated by static adsorption test. Elemental analysis by energy dispersive spectrometer of X-rays (EDS) and identifying of functional groups by Fourier transform infrared spectroscopy (FTIR) were used to analyze the preparation and adsorption of the adsorbent, and the reaction mechanism of cross-linking and adsorption was investigated. The results show that the adsorption performance of P-CCTS towards sulfate ion is 10 times higher than that of unmodified chitosan, and formaldehyde and glutaraldehyde mainly react with amino (-NH2) and part of hydroxy (C6-OH) of chitosn. A salt of chitosan protonated amino chlorine was formed through the process of the protonation of amino, the adsorption of sulfate ion mainly occurs on the protonated amino on which ion exchange happened between chlorine ion and sulfate ion.

  4. Superadsorption of LiOH solution on chitosan as a new type of solvent for chitosan by freezing/blasting.

    Science.gov (United States)

    Fan, Min; Hu, Qiaoling

    2013-04-15

    The adsorption behavior and mechanism of chitosan in aqueous LiOH solution was studied systemically. The results showed that the adsorption of chitosan was mainly due to the breakage of its hydrogen bonds, which were destroyed by the reaction of LiOH with the acetyl and the hydroxyl groups of chitosan. Low temperature also played a crucial role in the adsorption of chitosan. The adsorption of chitosan decreased with increased DD. The adsorption ratio of LiOH to chitosan (nLiOH/nCS) increased linearly while the adsorption ratio of water to chitosan (n(H2O)/n(CS)) decreased with the increased DD. All chitosans reached their maximal swelling degree when the concentration of LiOH was 4.8 wt%. Chitosan was stable in LiOH aqueous solution. The LiOH solution may be a potential favorable solvent for chitosan.

  5. Chitosan magnetic nanoparticles for drug delivery systems.

    Science.gov (United States)

    Assa, Farnaz; Jafarizadeh-Malmiri, Hoda; Ajamein, Hossein; Vaghari, Hamideh; Anarjan, Navideh; Ahmadi, Omid; Berenjian, Aydin

    2016-06-01

    The potential of magnetic nanoparticles (MNPs) in drug delivery systems (DDSs) is mainly related to its magnetic core and surface coating. These coatings can eliminate or minimize their aggregation under physiological conditions. Also, they can provide functional groups for bioconjugation to anticancer drugs and/or targeted ligands. Chitosan, as a derivative of chitin, is an attractive natural biopolymer from renewable resources with the presence of reactive amino and hydroxyl functional groups in its structure. Chitosan nanoparticles (NPs), due to their huge surface to volume ratio as compared to the chitosan in its bulk form, have outstanding physico-chemical, antimicrobial and biological properties. These unique properties make chitosan NPs a promising biopolymer for the application of DDSs. In this review, the current state and challenges for the application magnetic chitosan NPs in drug delivery systems were investigated. The present review also revisits the limitations and commercial impediments to provide insight for future works.

  6. Chitosan dan Aplikasi Klinisnya Sebagai Biomaterial

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The development of new materials with both organic and inorganic structures is of great interest to obtain special material properties. Chitosan [2-amino-2-deoxy-D-glucan] can be obtained by N-deacetylation of chitin. Chitin is the second most abundant biopolymer in nature and the supporting material of crustaceans, insects, fungi etc. Chitosan is unique polysaccharide and has been widely used in various biomedical application due to its biocompatibility, low toxicity, biodegradability, non-immunogenic and non-carcinogenic character. In the past few years, chitosan and some of its modifications have been reported for use in biomedical applications such as artificial skin, wound dressing, anticoagulant, suture, drug delivery, vaccine carrier and dietary fibers. Recently, the use of chitosan and its derivatives has received much attention as temporary scaffolding to promotie mineralization or stimulate endochodral ossification. This article aims to give a broad overview of chitosan and its clinical applications as biomaterial.

  7. Hydrogels made from chitosan and silver nitrate.

    Science.gov (United States)

    Kozicki, Marek; Kołodziejczyk, Marek; Szynkowska, Małgorzata; Pawlaczyk, Aleksandra; Leśniewska, Ewa; Matusiak, Aleksandra; Adamus, Agnieszka; Karolczak, Aleksandra

    2016-04-20

    This work describes a gelation of chitosan solution with silver nitrate. Above the critical concentration of chitosan (c*), continuous hydrogels of chitosan-silver can be formed. At lower concentrations, the formation of nano- and micro-hydrogels is discussed. The sol-gel analysis was performed to characterise the hydrogels' swelling properties. Moreover, the following were employed: (i) mechanical testing of hydrogels, (ii) inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the measurement of silver concentration, (iii) scanning electron microscopy (SEM) to examine the morphology of products obtained, and (iv) dynamic light scattering (DLS) and UV-vis spectrophotometry to examine products formed at low concentration of chitosan (chydrogels were used for modification of cotton fabric in order to give it antimicrobial properties. The products obtained acted against Escherichia coli and Bacillus subtilis apart from the chitosan used that showed no such activity.

  8. Vacuum-assisted infiltration of chitosan or polycaprolactone as a structural reinforcement for sintered cancellous bovine bone graft.

    Science.gov (United States)

    Laird, Dougal F; Mucalo, Michael R; Dias, George J

    2012-10-01

    Sintered cancellous bovine bone (SCBB) offers numerous advantages as a bone graft substitute material; however, its mechanical properties require improvement. In this study, SCBB was infiltrated with ε-polycaprolactone (PCL) or chitosan/monetite to improve mechanical properties while retaining valuable SCBB structure. Organic infiltrating solutions consisted of (i) chitosan and monetite (CaHPO(4)) dissolved in hydrochloric acid; (ii) chitosan, monetite (CaHPO(4)), and genipin dissolved in hydrochloric acid; or (iii) PCL polymer dissolved in tetrahydrofuran (THF). Porous SCBB materials were infiltrated with one of the three solutions using vacuum-assisted infiltration. Chitosan and CaHPO(4) were immobilized in the SCBB structure by reprecipitation following a pH increase in an ammonia atmosphere. Genipin was used in one sample group to immobilize chitosan via crosslinking. PCL was immobilized by evaporating the THF carrier solvent. Mechanical compression testing showed an improvement in ultimate stress for the SCBB with chitosan/CaHPO(4) infiltrates, whereas PCL samples showed an increase in modulus. All SCBB samples were found to demonstrate favorable in vitro biocompatibility when subjected to L929 mouse fibroblast cells but required a vigorous washing regime to eradicate toxic ammonia residue. In conclusion, infiltration of SCBB with a polymeric or organic/mineral composite matrix positively modifies SCBB mechanical properties in favor of bone grafting applications.

  9. Maize, tropical (Zea mays L.).

    Science.gov (United States)

    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

  10. Antimicrobial and antitumor activities of chitosan from shiitake stipes, compared to commercial chitosan from crab shells.

    Science.gov (United States)

    Chien, Rao-Chi; Yen, Ming-Tsung; Mau, Jeng-Leun

    2016-03-15

    Chitosan was prepared by alkaline N-deacetylation of chitin obtained from shiitake stipes and crab shells and its antimicrobial and antitumor activities were studied. Chitosan from shiitake stipes and crab shells exhibited excellent antimicrobial activities against eight species of Gram positive and negative pathogenic bacteria with inhibition zones of 11.4-26.8mm at 0.5mg/ml. Among chitosan samples, shiitake chitosan C120 was the most effective with inhibition zones of 16.4-26.8mm at 0.5mg/ml. In addition, shiitake and crab chitosan showed a moderate anti-proliferative effect on IMR 32 and Hep G2 cells. At 5mg/ml, the viability of IMR 32 cells incubated with chitosan was 68.8-85.0% whereas that of Hep G2 cells with chitosan was 60.4-82.9%. Overall, shiitake chitosan showed slightly better antimicrobial and antitumor activities than crab chitosan. Based on the results obtained, shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents.

  11. New inoculants on maize silage fermentation

    Directory of Open Access Journals (Sweden)

    Fábia Giovana do Val de Assis

    2014-08-01

    Full Text Available The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1 of forage for each strain of lactic acid bacteria (LAB identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, water-soluble carbohydrates (WSC, organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT and aerobic stability (AS, was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.

  12. In Vivo Assessment of Clobetasol Propionate-Loaded Lecithin-Chitosan Nanoparticles for Skin Delivery

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    Taner Şenyiğit

    2016-12-01

    Full Text Available The aim of this work was to assess in vivo the anti-inflammatory efficacy and tolerability of clobetasol propionate (CP loaded lecithin/chitosan nanoparticles incorporated into chitosan gel for topical application (CP 0.005%. As a comparison, a commercial cream (CP 0.05% w/w, and a sodium deoxycholate gel (CP 0.05% w/w were also evaluated. Lecithin/chitosan nanoparticles were prepared by self-assembling of the components obtained by direct injection of soybean lecithin alcoholic solution containing CP into chitosan aqueous solution. Nanoparticles obtained had a particle size around 250 nm, narrow distribution (polydispersity index below 0.2 and positive surface charge, provided by a superficial layer of the cationic polymer. The nanoparticle suspension was then loaded into a chitosan gel, to obtain a final CP concentration of 0.005%. The anti-inflammatory activity was evaluated using carrageenan-induced hind paw edema test on Wistar rats, the effect of formulations on the barrier property of the stratum corneum were determined using transepidermal water loss measurements (TEWL and histological analysis was performed to evaluate the possible presence of morphological changes. The results obtained indicate that nanoparticle-in-gel formulation produced significantly higher edema inhibition compared to other formulations tested, although it contained ten times less CP. TEWL measurements also revealed that all formulations have no significant disturbance on the barrier function of skin. Furthermore, histological analysis of rat abdominal skin did not show morphological tissue changes nor cell infiltration signs after application of the formulations. Taken together, the present data show that the use of lecithin/chitosan nanoparticles in chitosan gel as a drug carrier significantly improves the risk-benefit ratio as compared with sodium-deoxycholate gel and commercial cream formulations of CP.

  13. Physicochemical properties and bioactivity of freeze-cast chitosan nanocomposite scaffolds reinforced with bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Pourhaghgouy, Masoud, E-mail: m.pourhaghgouy@merc.ac.ir [Department of Nanotechnology & Advanced Materials, Materials & Energy Research Center, Karaj, P.O. Box: 13145-1659 (Iran, Islamic Republic of); Zamanian, Ali, E-mail: a-zamanian@merc.ac.ir [Department of Nanotechnology & Advanced Materials, Materials & Energy Research Center, Karaj, P.O. Box: 13145-1659 (Iran, Islamic Republic of); Shahrezaee, Mostafa, E-mail: moshahrezaee@yahoo.com [Department of Orthopedic Surgery, AJA University of Medical Sciences, Tehran (Iran, Islamic Republic of); Masouleh, Milad Pourbaghi, E-mail: miladpourbaghi@gmail.com [Department of Nanotechnology & Advanced Materials, Materials & Energy Research Center, Karaj, P.O. Box: 13145-1659 (Iran, Islamic Republic of)

    2016-01-01

    Chitosan based nanocomposite scaffolds were prepared by freeze casting method through blending constant chitosan concentration with different portions of synthesized bioactive glass nanoparticles (BGNPs). Transmission Electron Microscopy (TEM) image showed that the particles size of bioactive glass (64SiO{sub 2}.28CaO.8P{sub 2}O{sub 5}) prepared by sol–gel method was approximately less than 20 nm. Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD) analysis showed proper interfacial bonding between BGNPs and chitosan polymers. Scanning Electron Microscopy (SEM) images depicted a unidirectional structure with homogenous distribution of BGNPs among chitosan matrix associated with the absence of pure chitosan scaffold's wall pores after addition of only 10 wt.% BGNPs. As the BGNP content increased from 0 to 50 wt.%, the compressive strength and compressive module values increased from 0.034 to 0.419 MPa and 0.41 to 10.77 MPa, respectively. Biodegradation study showed that increase in BGNP content leads to growth of weight loss amount. The in vitro biomineralization studies confirmed the bioactive nature of all nanocomposites. Amount of 30 wt.% BGNPs represented the best concentration for absorption capacity and bioactivity behaviors. - Highlights: • Particle size of synthesized bioactive glass was approximately less than 20 nm. • Increase in BGNP content did not change the pore channels size. • Addition of 10 wt.% of BGNP led to absence of the pores located on chitosan walls. • Mechanical properties of chitosan scaffold significantly improved by addition of BGNPs. • Chi-BGNPs30 scaffold indicated acceptable absorption capacity and bioactivity behavior.

  14. MONTHLY PRICE ANALYSIS OF COWPEA (BEANS AND MAIZE IN AKWA IBOM STATE, SOUTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Sunday Brownson Akpan

    2014-04-01

    on the findings, it is recommended that, the Akwa Ibom State government should continue to provide marketing infrastructures and reduced externality costs in order to improve further the symmetric nature of information flow among Maize and Beans markets in the state. Also, individuals, trade unions, NGOs’ and government should established market information units and awareness programmes on mass media to facilitate efficient communication flows of Beans and Maize markets in the state.

  15. Genetic diversity among yellow maize with pro-vitamin A content

    Directory of Open Access Journals (Sweden)

    Mercy Oluremi Olowolafe

    2016-06-01

    Full Text Available An improvement in the concentration of vitamin A in adapted yellow maize varieties grown in Africa can have a positive impact on the dietary intakes in regions where maize is a staple food. The present study was designed to identify heterotic groups and divergent parents for developing new pro-vitamin A enriched maize lines. Ten Simple Sequence Repeats (SSR markers were used to generate DNA profiles among thirteen commonly grown yellow maize lines across south western Nigeria and three high pro-vitamin A lines from International Institute of Tropical Agriculture (IITA, Ibadan. The result obtained estimated 100% polymorphism among the ten SSR markers with polymorphic information content that ranged from 0.28 to 0.71 on an average of 0.50. Genetic similarity coefficients among the 16 maize lines varied from 0.28 to 0.92 GS with an average of 0.63 GS. Four well defined groups were identified at 0.65 GS with an IITA line, PVA8, solely, formed a group. The study identified PVA8 and its most three distant relatives as potential divergent parents that could serve as important genetic resources for broadening the genetic base of the presently assessed IAR&T maize collections and also to develop new maize lines with higher level of pro-vitamin A content.

  16. Alginate Hydrogels Coated with Chitosan for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Maria Cristina Straccia

    2015-05-01

    Full Text Available In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl, with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.

  17. One-step electrospinning of cross-linked chitosan fibers.

    Science.gov (United States)

    Schiffman, Jessica D; Schauer, Caroline L

    2007-09-01

    Chitin is a nitrogen-rich polysaccharide that is abundant in crustaceans, mollusks, insects, and fungi and is the second most abundant organic material found in nature next to cellulose. Chitosan, the N-deacetylated derivative of chitin, is environmentally friendly, nontoxic, biodegradable, and antibacterial. Fibrous mats are typically used in industries for filter media, catalysis, and sensors. Decreasing fiber diameters within these mats causes many beneficial effects such as increased specific surface area to volume ratios. When the intrinsically beneficial effects of chitosan are combined with the enhanced properties of nanofibrous mats, applications arise in a wide range of fields, including medical, packaging, agricultural, and automotive. This is particularly important as innovative technologies that focus around bio-based materials are currently of high urgency, as they can decrease dependencies on fossil fuels. We have demonstrated that Schiff base cross-linked chitosan fibrous mats can be produced utilizing a one-step electrospinning process that is 25 times faster and, therefore, more economical than a previously reported two-step vapor-cross-linking method. These fibrous mats are insoluble in acidic, basic, and aqueous solutions for 72 h. Additionally, this improved production method results in a decreased average fiber diameter, which measures 128 +/- 40 nm. Chemical and structural analyses were conducted utilizing Fourier transform infrared spectroscopy, solubility studies, and scanning electron microscopy.

  18. Dyeing Characteristics of Chitosan Biguanidine Hydrochloride Treated Wool Fabrics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chitosan biguanidine hydrochloride(CGH) has been synthesized by the guanidineylation reaction of chitosan with dicyandiamide.The structures of CGH were characterized by Fourier transform infrared spectroscopy and 13CNMR spectra.In this paper,we used citric acid(CA) as a crosslinking agent,mixed with CGH to perform a pad-drycure treatment on wool fabric to study reaction mechanism during crosslinking with the help of Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM).Dyeing characteristics of CGH treated wool fabric was assessed.The effects of CGH concentration,curing temperature,dipping time,pH value on color yield of reactive dyes on wool fibres were investigated.Fastness properties of the modified wool fabric to laundering and crocking have also been discussed.Fourier transform infrared spectroscopy(FT-IR) showed that CA produce esterification with the-OH group of the wool and transamidation with the-NH2 group of the CGH to form a crosslink.Scanning electron microscopy(SEM) analysis showed the CGH firmly attached to the surface of wool fibre.It was found that the CGH pretreated wool fabrics had significantly improved dyeability characteristics.It is worthwhile to mention that the CGH treated samples have antibacterial potential due to the antibacterial property of chitosan molecules and guanidinium salts.

  19. Superporous polyacrylate/chitosan IPN hydrogels for protein delivery.

    Science.gov (United States)

    Gümüşderelioğlu, Menemşe; Erce, Deniz; Demirtaş, T Tolga

    2011-11-01

    In this study, poly(acrylamide), poly(AAm), and poly(acrylamide-co-acrylic acid), poly(AAm-co-AA) superporous hydrogels (SPHs) were synthesized by radical polymerization in the presence of gas blowing agent, sodium bicarbonate. In addition, ionically crosslinked chitosan (CH) superporous hydrogels were synthesized to form interpenetrating superporous hydrogels, i.e. poly(AAm)-CH and poly(AAm-co-AA)-CH SPH-IPNs. The hydrogels have a structure of interconnected pores with pore sizes of approximately 100-150 μm. Although the extent of swelling increased when AA were incorporated to the poly(AAm) structure, the time to reach the equilibrium swelling (~30 s) was not affected so much. In the presence of chitosan network mechanical properties significantly improved when compared with SPHs, however, equilibrium swelling time (~30 min) was prolonged significantly as due to the lower porosities and pore sizes of SPH-IPNs than that of SPHs. Model protein bovine serum albumin (BSA) was loaded into SPHs and SPH-IPNs by solvent sorption in very short time (<1 h) and very high capacities (~30-300 mg BSA/g dry gel) when compared to conventional hydrogels. BSA release profiles from SPHs and SPH-IPNs were characterized by an initial burst of protein during the first 20 min followed by a completed release within 1 h. However, total releasable amount of BSA from SPH-IPNs was lower than that of SPHs as due to the electrostatic interactions between chitosan and BSA.

  20. Alginate hydrogels coated with chitosan for wound dressing.

    Science.gov (United States)

    Straccia, Maria Cristina; d'Ayala, Giovanna Gomez; Romano, Ida; Oliva, Adriana; Laurienzo, Paola

    2015-05-11

    In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC) were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.

  1. Enhancement of Curcumin Bioavailability Using Nanocellulose Reinforced Chitosan Hydrogel

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    Thennakoon M. Sampath Udeni Gunathilake

    2017-02-01

    Full Text Available A unique biodegradable, superporous, swellable and pH sensitive nanocellulose reinforced chitosan hydrogel with dynamic mechanical properties was prepared for oral administration of curcumin. Curcumin, a less water-soluble drug was used due to the fact that the fast swellable, superporous hydrogel could release a water-insoluble drug to a great extent. CO2 gas foaming was used to fabricate hydrogel as it eradicates using organic solvents. Field emission scanning electron microscope images revealed that the pore size significantly increased with the formation of widely interconnected porous structure in gas foamed hydrogels. The maximum compression of pure chitosan hydrogel was 25.9 ± 1 kPa and it increased to 38.4 ± 1 kPa with the introduction of 0.5% cellulose nanocrystals. In vitro degradation of hydrogels was found dependent on the swelling ratio and the amount of CNC of the hydrogel. All the hydrogels showed maximum swelling ratios greater than 300%. The 0.5% CNC-chitosan hydrogel showed the highest swelling ratio of 438% ± 11%. FTIR spectrum indicated that there is no interaction between drug and ingredients present in hydrogels. The drug release occurred in non-Fickian (anomalous manner in simulated gastric medium. The drug release profiles of hydrogels are consistent with the data obtained from the swelling studies. After gas foaming of the hydrogel, the drug loading efficiency increased from 41% ± 2.4% to 50% ± 2.0% and release increased from 0.74 to 1.06 mg/L. The drug release data showed good fitting to Ritger-Peppas model. Moreover, the results revealed that the drug maintained its chemical activity after in vitro release. According to the results of this study, CNC reinforced chitosan hydrogel can be suggested to improve the bioavailability of curcumin for the absorption from stomach and upper intestinal tract.

  2. Chitosan-gelatin scaffolds for tissue engineering: physico-chemical properties and biological response of buffalo embryonic stem cells and transfectant of GFP-buffalo embryonic stem cells.

    Science.gov (United States)

    Thein-Han, W W; Saikhun, J; Pholpramoo, C; Misra, R D K; Kitiyanant, Y

    2009-11-01

    The favorable cellular response of newly developed cell line, buffalo embryonic stem (ES) cells to three-dimensional biodegradable chitosan-gelatin composite scaffolds with regard to stem-cell-based tissue engineering is described. Chitosan-gelatin composites were characterized by a highly porous structure with interconnected pores, and the mechanical properties were significantly enhanced. Furthermore, X-ray diffraction study indicated increased amorphous content in the scaffold on the addition of gelatin to chitosan. To develop a transfectant of green fluorescence protein (GFP)-buffalo ES cell, transfection of GFP plasmid to the cell was carried out via the electroporation procedure. In comparison with pure chitosan, cell spreading and proliferation were greater in highly visualized GFP-expressing cell-chitosan-gelatin scaffold constructs. The relative comparison of biological response involving cell proliferation and viability on the scaffolds suggests that blending of gelatin in chitosan improved cellular efficiency. Studies involving scanning electron and fluorescence microscopy, histological observations and flow cytometer analysis of the constructs implied that the polygonal cells attached to and penetrated the pores, and proliferated well, while maintaining their pluripotency during the culture period for 28days. Chitosan-gelatin scaffolds were cytocompatible with respect to buffalo ES cells. The study underscores for the first time that chitosan-gelatin scaffolds are promising candidates for ES-cell-based tissue engineering.

  3. Thermo-responsive wound dressings by grafting chitosan and poly(N-isopropylacrylamide) to plasma-induced graft polymerization modified non-woven fabrics

    Science.gov (United States)

    Chen, Jyh-Ping; Kuo, Chang-Yi; Lee, Wen-Li

    2012-12-01

    To obtain a chitosan wound dressings with temperature-responsive characteristics, polypropylene (PP) non-woven fabric (NWF) was modified by direct current pulsed oxygen plasma-induced grafting polymerization of acrylic acid (AAc) to improve hydrophilicity and to introduce carboxylic acid groups. Conjugation of chitosan and poly(N-isopropylacrylamide) (PNIPAAm) followed by using water-soluble carbodiimide as a coupling agent to form a novel bigraft PP-g-chitosan-g-PNIPAAm wound dressing. The amount of chitosan and PNIPAAm grafted to PP-g-chitosan-g-PNIPAAm were 83.0 ± 4.6 μg/cm2 and 189.5 ± 8.2 μg/cm2, respectively. The surface chemical composition and microstructure of the NWF were studied by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy (SEM). The linkages between AAc, chitosan, and PNIPAAm were confirmed with the formation of amide bonds. Physical properties of the NWF were characterized and potentials of these NWFs as wound dressings were evaluated using SD rat as the animal model. NWFs contained PNIPAAm were better than those contained only chitosan in wound healing rates and the wound areas covered by PP-g-chitosan-g-PNIPAAm wound dressings healed completely in 17 days.

  4. Functional modification of chitosan for biomedical application

    Science.gov (United States)

    Tang, Ruogu

    Chitosan is a linear polysaccharide. Normally commercial chitosan consists of randomly distributed beta-(1-4)-linked D-glucosamine (deacetylated proportion) and N-acetyl-D-glucosamine (acetylated proportion) together. Chitosan has been proved to be a multifunctional biopolymer that presents several unique properties due to free amino groups in the repeating unit therefore chitosan has been widely applied in various areas. To be specific, provided by the excellent biocompatibility, chitosan is expected to be used in biological and medical applications including wound dressing, implants, drug carrier/delivery, etc. In this thesis, we worked on chitosan functionalization for biomedical application. The thesis are composed of three parts: In the first part, we focused on modifying the chitosan thin film, chemically introducing the nitric oxide functional groups on chitosan film. We covalently bonded small molecule diazeniumdiolates onto the chitosan films and examined the antimicrobial function and biocompatibility. Commercial chitosan was cast into films from acidic aqueous solutions. Glutaraldehyde reacted with the chitosan film to introduce aldehyde groups onto the chitosan film (GA-CS film). GA-CS reacted with a small molecule NO donor, NOC-18, to covalently immobilize NONO groups onto the polymer (NO-CS film). The-CHO and [NONO] group were verified by FT IR, UV and Griess reagent. The NO releasing rate in aqueous solution and and thermal stability were studied quantitatively to prove its effectiveness. A series of antimicrobial tests indicated that NO-CS films have multiple functions: 1. It could inhibit the bacteria growth in nutrient rich environment; 2. It could directly inactivate bacteria and biofilm; 3. It could reduce the bacteria adherence on the film surface as well as inhibit biofilm formation. In addition, the NO-CS film was proved to be biocompatible with cell and it was also compatible with other antibiotics like Amoxicillin. In the second part, we

  5. Increased maize yield using slow-release attapulgite-coated fertilizers

    OpenAIRE

    Guan, Yu; Song, Chao; Gan, Yantai; Li, Feng-Min

    2014-01-01

    International audience; Slow-release fertilizers could improve the productivity of field crops and reduce environmental pollution. So far, no slow-release fertilizers are suited for maize cultivation in semiarid areas of China. Therefore, we tested attapulgite-coated fertilizers. Attapulgite-coated fertilizers were prepared by dividing chemical fertilizers into three parts according to the nutrient demand of maize in its three main growth stages and coating each part with a layer of attapulgi...

  6. 3D composites based on the blends of chitosan and collagen with the addition of hyaluronic acid.

    Science.gov (United States)

    Sionkowska, Alina; Kaczmarek, Beata; Lewandowska, Katarzyna; Grabska, Sylwia; Pokrywczyńska, Marta; Kloskowski, Tomasz; Drewa, Tomasz

    2016-08-01

    3D porous composites based on blends of chitosan, collagen and hyaluronic acid were obtained through the lyophilization process. Mechanical properties, swelling behavior and thermal stability of the blends were studied. Moreover, SEM images were taken and the structure of the blends was studied. Biological properties of the materials obtained were investigated by analyzing of proliferation rate of fibroblast cells incubated with biomaterial extract using MTT assay (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide). The results showed that the properties of 3D composites based on the blends of chitosan and collagen were altered after the addition 1%, 2% and 5% of hyaluronic acid. Mechanical properties and thermal stability of chitosan/collagen blends were improved in the presence of hyaluronic acid in the composite. New 3D materials based on the blends of chitosan, collagen and hyaluronic acid were non-toxic and did not significantly affect cell morphology.

  7. Natural-synthetic hybrid polymers developed via electrospinning: the effect of PET in chitosan/starch system.

    Science.gov (United States)

    Espíndola-González, Adolfo; Martínez-Hernández, Ana Laura; Fernández-Escobar, Francisco; Castaño, Victor Manuel; Brostow, Witold; Datashvili, Tea; Velasco-Santos, Carlos

    2011-01-01

    Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties has emerged by combining it with synthetic materials to produce novel natural-synthetic hybrid polymers. We have studied structural and thermophysical properties of chitosan + starch + poly(ethylene terephthalate) (Ch + S + PET) fibers developed via electrospinning. Properties of these hybrids polymers are compared with extant chitosan containing hybrids synthesized by electrospinning. Molecular interactions and orientation in the fibers are analyzed by infrared and Raman spectroscopies respectively, morphology by scanning electron microscopy and thermophysical properties by thermogravimetric analysis and differential scanning calorimetry. Addition of PET to Ch + S systems results in improved thermal stability at elevated temperatures.

  8. Natural-Synthetic Hybrid Polymers Developed via Electrospinning: The Effect of PET in Chitosan/Starch System

    Directory of Open Access Journals (Sweden)

    Carlos Velasco-Santos

    2011-03-01

    Full Text Available Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties has emerged by combining it with synthetic materials to produce novel natural-synthetic hybrid polymers. We have studied structural and thermophysical properties of chitosan + starch + poly(ethylene terephthalate (Ch + S + PET fibers developed via electrospinning. Properties of these hybrids polymers are compared with extant chitosan containing hybrids synthesized by electrospinning. Molecular interactions and orientation in the fibers are analyzed by infrared and Raman spectroscopies respectively, morphology by scanning electron microscopy and thermophysical properties by thermogravimetric analysis and differential scanning calorimetry. Addition of PET to Ch + S systems results in improved thermal stability at elevated temperatures.

  9. New type of chitosan/2-hydroxypropyl-β-cyclodextrin composite membrane for gallic acid encapsulation and controlled release.

    Science.gov (United States)

    Paun, Gabriela; Neagu, Elena; Tache, Andreia; Radu, G L

    2014-01-01

    A new type of chitosan/2-hydroxypropyl-β-cyclodextrin composite membrane have been developed for the encapsulation and controlled release of gallic acid. The morphology of the composite membrane was investigated by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), whereas swelling gallic acid and release properties were investigated by UV-visible spectroscopy. The release behavior with pH changes was also explored. The composite membrane based on chitosan/2-hydroxypropyl-β-cyclodextrin with gallic acid included showed improved antioxidant capacities compared to plain chitosan membrane. The information obtained in this study will facilitate the design and preparation of composite membrane based on chitosan and could open a wide range of applications, particularly its use as an antioxidant in food, food packaging, biomedical (biodegradable soft porous scaffolds for enhance the surrounding tissue regeneration), pharmaceutical and cosmetics industries.

  10. Global maize production, utilization, and consumption.

    Science.gov (United States)

    Ranum, Peter; Peña-Rosas, Juan Pablo; Garcia-Casal, Maria Nieves

    2014-04-01

    Maize (Zea mays), also called corn, is believed to have originated in central Mexico 7000 years ago from a wild grass, and Native Americans transformed maize into a better source of food. Maize contains approximately 72% starch, 10% protein, and 4% fat, supplying an energy density of 365 Kcal/100 g and is grown throughout the world, with the United States, China, and Brazil being the top three maize-producing countries in the world, producing approximately 563 of the 717 million metric tons/year. Maize can be processed into a variety of food and industrial products, including starch, sweeteners, oil, beverages, glue, industrial alcohol, and fuel ethanol. In the last 10 years, the use of maize for fuel production significantly increased, accounting for approximately 40% of the maize production in the United States. As the ethanol industry absorbs a larger share of the maize crop, higher prices for maize will intensify demand competition and could affect maize prices for animal and human consumption. Low production costs, along with the high consumption of maize flour and cornmeal, especially where micronutrient deficiencies are common public health problems, make this food staple an ideal food vehicle for fortification.

  11. Preparation and characterization of collagen/PLA, chitosan/PLA, and collagen/chitosan/PLA hybrid scaffolds for cartilage tissue engineering.

    Science.gov (United States)

    Haaparanta, Anne-Marie; Järvinen, Elina; Cengiz, Ibrahim Fatih; Ellä, Ville; Kokkonen, Harri T; Kiviranta, Ilkka; Kellomäki, Minna

    2014-04-01

    In this study, three-dimensional (3D) porous scaffolds were developed for the repair of articular cartilage defects. Novel collagen/polylactide (PLA), chitosan/PLA, and collagen/chitosan/PLA hybrid scaffolds were fabricated by combining freeze-dried natural components and synthetic PLA mesh, where the 3D PLA mesh gives mechanical strength, and the natural polymers, collagen and/or chitosan, mimic the natural cartilage tissue environment of chondrocytes. In total, eight scaffold types were studied: four hybrid structures containing collagen and/or chitosan with PLA, and four parallel plain scaffolds with only collagen and/or chitosan. The potential of these types of scaffolds for cartilage tissue engineering applications were determined by the analysis of the microstructure, water uptake, mechanical strength, and the viability and attachment of adult bovine chondrocytes to the scaffolds. The manufacturing method used was found to be applicable for the manufacturing of hybrid scaffolds with highly porous 3D structures. All the hybrid scaffolds showed a highly porous structure with open pores throughout the scaffold. Collagen was found to bind water inside the structure in all collagen-containing scaffolds better than the chitosan-containing scaffolds, and the plain collagen scaffolds had the highest water absorption. The stiffness of the scaffold was improved by the hybrid structure compared to plain scaffolds. The cell viability and attachment was good in all scaffolds, however, the collagen hybrid scaffolds showed the best penetration of cells into the scaffold. Our results show that from the studied scaffolds the collagen/PLA hybrids are the most promising scaffolds from this group for cartilage tissue engineering.

  12. Development, optimization and biological evaluation of chitosan scaffold formulations of new xanthine derivatives for treatment of type-2 diabetes mellitus.

    Science.gov (United States)

    Lupascu, Florentina Geanina; Dash, Mamoni; Samal, Sangram Keshari; Dubruel, Peter; Lupusoru, Catalina Elena; Lupusoru, Raoul-Vasile; Dragostin, Oana; Profire, Lenuta

    2015-09-18

    New xanthine derivatives as antidiabetic agents were synthesized and new chitosan formulations have been developed in order to improve their biological and pharmacokinetic profile. Their physicochemical properties in terms of particle size, morphology, swelling degree, crystalline state, the loading efficiency as well as in vitro release and biodegradation rate were evaluated. According to the results the optimized formulations have a high drug loading efficiency (more than 70%), small particle size, a good release profile in the simulated biological fluids (the percentage of cumulative release being more than 55%) and improved biodegradation rate in reference with chitosan microparticles. The presence of xanthine derivatives (6, 7) in chitosan microparticles was demonstrated by means of FTIR analysis. The X-ray diffraction (XRD) proved that xanthine derivatives present a crystalline state. The biological evaluation assays confirmed the antioxidant and antidiabetic effects of the xanthine derivatives (6, 7) and their chitosan formulations (CS-6, CS-7). Xanthine derivative 6 showed a high antiradical scavenging effect (DPPH remaining=41.78%). It also reduced the glucose blood level with 59.30% and recorded level of glycosylated hemoglobin was 4.53%. The effect of its chitosan formulation (CS-6) on the level of blood glucose (114.5mg/dl) was even more intense than the one recorded by pioglitazone (148.5mg/dl) when used as standard antidiabetic drug. These results demonstrated the potential application of xanthine derivative 6 and its chitosan formulation (CS-6) in the treatment of the diabetes mellitus syndrome.

  13. The B73 maize genome: complexity, diversity, and dynamics.

    Science.gov (United States)

    Schnable, Patrick S; Ware, Doreen; Fulton, Robert S; Stein, Joshua C; Wei, Fusheng; Pasternak, Shiran; Liang, Chengzhi; Zhang, Jianwei; Fulton, Lucinda; Graves, Tina A; Minx, Patrick; Reily, Amy Denise; Courtney, Laura; Kruchowski, Scott S; Tomlinson, Chad; Strong, Cindy; Delehaunty, Kim; Fronick, Catrina; Courtney, Bill; Rock, Susan M; Belter, Eddie; Du, Feiyu; Kim, Kyung; Abbott, Rachel M; Cotton, Marc; Levy, Andy; Marchetto, Pamela; Ochoa, Kerri; Jackson, Stephanie M; Gillam, Barbara; Chen, Weizu; Yan, Le; Higginbotham, Jamey; Cardenas, Marco; Waligorski, Jason; Applebaum, Elizabeth; Phelps, Lindsey; Falcone, Jason; Kanchi, Krishna; Thane, Thynn; Scimone, Adam; Thane, Nay; Henke, Jessica; Wang, Tom; Ruppert, Jessica; Shah, Neha; Rotter, Kelsi; Hodges, Jennifer; Ingenthron, Elizabeth; Cordes, Matt; Kohlberg, Sara; Sgro, Jennifer; Delgado, Brandon; Mead, Kelly; Chinwalla, Asif; Leonard, Shawn; Crouse, Kevin; Collura, Kristi; Kudrna, Dave; Currie, Jennifer; He, Ruifeng; Angelova, Angelina; Rajasekar, Shanmugam; Mueller, Teri; Lomeli, Rene; Scara, Gabriel; Ko, Ara; Delaney, Krista; Wissotski, Marina; Lopez, Georgina; Campos, David; Braidotti, Michele; Ashley, Elizabeth; Golser, Wolfgang; Kim, HyeRan; Lee, Seunghee; Lin, Jinke; Dujmic, Zeljko; Kim, Woojin; Talag, Jayson; Zuccolo, Andrea; Fan, Chuanzhu; Sebastian, Aswathy; Kramer, Melissa; Spiegel, Lori; Nascimento, Lidia; Zutavern, Theresa; Miller, Beth; Ambroise, Claude; Muller, Stephanie; Spooner, Will; Narechania, Apurva; Ren, Liya; Wei, Sharon; Kumari, Sunita; Faga, Ben; Levy, Michael J; McMahan, Linda; Van Buren, Peter; Vaughn, Matthew W; Ying, Kai; Yeh, Cheng-Ting; Emrich, Scott J; Jia, Yi; Kalyanaraman, Ananth; Hsia, An-Ping; Barbazuk, W Brad; Baucom, Regina S; Brutnell, Thomas P; Carpita, Nicholas C; Chaparro, Cristian; Chia, Jer-Ming; Deragon, Jean-Marc; Estill, James C; Fu, Yan; Jeddeloh, Jeffrey A; Han, Yujun; Lee, Hyeran; Li, Pinghua; Lisch, Damon R; Liu, Sanzhen; Liu, Zhijie; Nagel, Dawn Holligan; McCann, Maureen C; SanMiguel, Phillip; Myers, Alan M; Nettleton, Dan; Nguyen, John; Penning, Bryan W; Ponnala, Lalit; Schneider, Kevin L; Schwartz, David C; Sharma, Anupma; Soderlund, Carol; Springer, Nathan M; Sun, Qi; Wang, Hao; Waterman, Michael; Westerman, Richard; Wolfgruber, Thomas K; Yang, Lixing; Yu, Yeisoo; Zhang, Lifang; Zhou, Shiguo; Zhu, Qihui; Bennetzen, Jeffrey L; Dawe, R Kelly; Jiang, Jiming; Jiang, Ning; Presting, Gernot G; Wessler, Susan R; Aluru, Srinivas; Martienssen, Robert A; Clifton, Sandra W; McCombie, W Richard; Wing, Rod A; Wilson, Richard K

    2009-11-20

    We report an improved draft nucleotide sequence of the 2.3-gigabase genome of maize, an important crop plant and model for biological research. Over 32,000 genes were predicted, of which 99.8% were placed on reference chromosomes. Nearly 85% of the genome is composed of hundreds of families of transposable elements, dispersed nonuniformly across the genome. These were responsible for the capture and amplification of numerous gene fragments and affect the composition, sizes, and positions of centromeres. We also report on the correlation of methylation-poor regions with Mu transposon insertions and recombination, and copy number variants with insertions and/or deletions, as well as how uneven gene losses between duplicated regions were involved in returning an ancient allotetraploid to a genetically diploid state. These analyses inform and set the stage for further investigations to improve our understanding of the domestication and agricultural improvements of maize.

  14. Field-evolved resistance to Bt maize by western corn rootworm.

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    Aaron J Gassmann

    Full Text Available BACKGROUND: Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae. METHODOLOGY/PRINCIPAL FINDINGS: We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. CONCLUSIONS/SIGNIFICANCE: This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary.

  15. Coloration of cotton fibers using nano chitosan.

    Science.gov (United States)

    Wijesena, Ruchira N; Tissera, Nadeeka D; de Silva, K M Nalin

    2015-12-10

    A method of coloration of cotton fabrics with nano chitosan is proposed. Nano chitosan were prepared using crab shell chitin nanofibers through alkaline deacetylation process. Average nano fiber diameters of nano chitosan were 18 nm to 35 nm and the lengths were in the range of 0.2-1.3 μm according to the atomic force microscope study. The degree of deacetylation of the material was found to be 97.3%. The prepared nano chitosan dyed using acid blue 25 (2-anthraquinonesulfonic acid) and used as the coloration agent for cotton fibers. Simple wet immersion method was used to color the cotton fabrics by nano chitosan dispersion followed by acid vapor treatment. Scanning electron microscope and atomic force microscope study of the treated cotton fiber revealed that the nano chitosan were consistently deposited on the cotton fiber surface and transformed in to a thin polymer layer upon the acid vapor treatment. The color strength of the dyed fabrics could be changed by changing the concentration of dyed nano chitosan dispersion.

  16. Effects of Chitosan Spraying on Physiological Characteristics of Ferula flabelliloba (Apiaceae Under Drought Stress

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    Gh. Taheri

    2016-02-01

    Full Text Available Introduction Ferula flabelliloba Rech. F. & Aell., (Apiaceae, a perennial plant with medicinal value, is one of important soil protective grown in Binalood mountains. Decreased precipitation in the previous years caused plants subjected to drought stress condition. Drought stress limits the growth and productivity of plants more than any other environmental factors. Drought stress can alter plant light absorption and consumption processes and increases production of reactive oxygen species (ROS. ROS is responsible for lipid peroxidation and associated injury to membranes, nucleic acids, proteins and enzymes. To detoxify ROS, plants develop different types of antioxidants to reduce oxidative damage and confer drought tolerance. ROS scavengers are either non- enzymatic (ascorbate, glutathione, flavonoids, alkaloids, carotenoids and phenolic compound or enzymatic containing superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase. The activity of these antioxidants and enzymes allows short-term acclimation to temporary water deficit, but these biochemicals cannot overcome the effects of extreme or prolonged drought. Chitosan is a natural biopolymer formed by low alkaline deacetylation of chitin, an important component of the exoskeletons of crustaceans such as crab, crawfish and shrimp. Chitosan can affect plant physiology and gene expression, hence these materials can increase the plant resistant to many unfavorable environmental condition. The biological properties of chitosan have led to use it for various purposes. Chitosan has been used as plant protectant against fungi, bacteria and viruses, to improve soil fertility and to stimulate plant defense system. Thus, it seems that chitosan is a promising material for improving plant growth, especially under drought stress conditions where water deficit limits plant growth and establishment. In the present study, the effects of chitosan as foliar spraying of F. flabelliloba

  17. Chitosan Nanoparticles Prepared by Ionotropic Gelation: An Overview of Recent Advances.

    Science.gov (United States)

    Desai, Kashappa Goud

    2016-01-01

    The objective of this review is to summarize recent advances in chitosan nanoparticles prepared by ionotropic gelation. Significant progress has occurred in this area since the method was first reported. The gelation technique has been improved through a number of creative methodological modifications. Ionotropic gelation via electrospraying and spinning disc processing produces nanoparticles with a more uniform size distribution. Large-scale manufacturing of the nanoparticles can be achieved with the latter approach. Hydrophobic and hydrophilic drugs can be simultaneously encapsulated with high efficiency by emulsification followed by ionic gelation. The turbulent mixing approach facilitates nanoparticle formation at a relatively high polymer concentration (5 mg/mL). The technique can be easily tuned to achieve the desired polymer/surface modifications (e.g., blending, coating, and surface conjugation). Using factorial-design-based approaches, optimal conditions for nanoparticle formation can be determined with a minimum number of experiments. New insights have been gained into the mechanism of chitosan-tripolyphosphate nanoparticle formation. Chitosan nanoparticles prepared by ionotropic gelation tend to aggregate/agglomerate in unfavorable environments. Factors influencing this phenomenon and strategies that can be adopted to minimize the instability are discussed. Ionically cross-linked nanoparticles based on native chitosan and modified chitosan have shown excellent efficacy for controlled and targeted drug-delivery applications.

  18. Preparation of a Novel Chitosan Based Biopolymer Dye and Application in Wood Dyeing

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    Xiaoqian Wang

    2016-09-01

    Full Text Available A novel chitosan-based biopolymer dye possessing antibacterial properties was synthesized by reaction of O-carboxymethyl chitosan and Acid Red GR. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FTIR, degree of substitution (DS, X-ray photoelectron spectroscopy (XPS, thermogravimetric analysis (TG, X-ray diffraction (XRD, water solubility test, antibacterial property test, and dyeing performance, including dye uptake, color difference, and fastness. Results showed that the synthesized dye was combined by –NH3+ of O-carboxymethyl chitosan and the sulfonic group of Acid Red GR. According to the comprehensive analysis of XRD and water solubility, the introduction of the carboxymethyl group and acid dye molecule changed the structure of the chitosan from compact to loose, which improved the synthesized dye’s water solubility. However, the thermal stability of the synthesized dye was decreased. The antibacterial property of the poplar wood dyed with the synthesized dye was enhanced and its antibacterial rate, specifically against Staphylococcus aureus and Escherichia coli, also increased to a rate of more than 99%. However, the dye uptake of the synthesized dye was lower than that of the original dye. Despite this, though, the dyeing effect of the synthesized dye demonstrated better water-fastness, and light-fastness than the original dye. Therefore, the novel chitosan-based biopolymer dye can be a promising product for wood dyeing.

  19. Spherical polystyrene-supported chitosan thin film of fast kinetics and high capacity for copper removal.

    Science.gov (United States)

    Jiang, Wei; Chen, Xubin; Pan, Bingcai; Zhang, Quanxing; Teng, Long; Chen, Yufan; Liu, Lu

    2014-07-15

    In order to accelerate the kinetics and improve the utilization of the surface active groups of chitosan (CS) for heavy metal ion removal, sub-micron-sized polystyrene supported chitosan thin-film was synthesized by the electrostatic assembly method. Glutaraldehyde was used as cross-linking agent. Chitosan thin-film was well coated onto the surface of the polystyrene (PS) beads characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Their adsorption toward Cu(II) ions was investigated as a function of solution pH, degree of cross-linking, equilibrium Cu(II) ions concentration and contact time. The maximum adsorptive capacity of PS-CS was 99.8 mg/g in the adsorption isotherm study. More attractively, the adsorption equilibrium was achieved in 10 min, which showed superior properties among similar adsorbents. Continuous adsorption-desorption cyclic results demonstrated that Cu(II)-loaded PS-CS can be effectively regenerated by a hydrochloric acid solution (HCl), and the regenerated composite beads could be employed for repeated use without significant capacity loss, indicating the good stability of the adsorbents. The XPS analysis confirmed that the adsorption process was due to surface complexes with atoms of chitosan. Generally, PS beads could be employed as a promising host to fabricate efficient composites that originated from chitosan or other bio-sorbents for environmental remediation.

  20. Physical and Oxidative Stability of Uncoated and Chitosan-Coated Liposomes Containing Grape Seed Extract

    Directory of Open Access Journals (Sweden)

    Jochen Weiss

    2013-08-01

    Full Text Available Polyphenol-rich grape seed extract (0.1 w/w% was incorporated in liposomes (1 w/w% soy lecithin by high pressure homogenization (22,500 psi and coated with chitosan (0.1 w/w%. Primary liposomes and chitosan-coated secondary liposomes containing grape seed extract showed good physical stability during 98 days of storage. Most of the polyphenols were incorporated in the shell of the liposomes (85.4%, whereas only 7.6% of the polyphenols of grape seed extract were located in the interior of the liposomes. Coating with chitosan did not change the polyphenol content in the liposomes (86.6%. The uncoated liposomes without grape seed extract were highly prone to lipid oxidation. The cationic chitosan coating, however, improved the oxidative stability to some extent, due to its ability to repel pro-oxidant metals. Encapsulated grape seed extract showed high antioxidant activity in both primary and secondary liposomes, which may be attributed to its polyphenol content. In conclusion, the best chemical stability of liposomes can be achieved using a combination of grape seed extract and chitosan.

  1. Physical and oxidative stability of uncoated and chitosan-coated liposomes containing grape seed extract.

    Science.gov (United States)

    Gibis, Monika; Rahn, Nina; Weiss, Jochen

    2013-08-20

    Polyphenol-rich grape seed extract (0.1 w/w%) was incorporated in liposomes (1 w/w% soy lecithin) by high pressure homogenization (22,500 psi) and coated with chitosan (0.1 w/w%). Primary liposomes and chitosan-coated secondary liposomes containing grape seed extract showed good physical stability during 98 days of storage. Most of the polyphenols were incorporated in the shell of the liposomes (85.4%), whereas only 7.6% of the polyphenols of grape seed extract were located in the interior of the liposomes. Coating with chitosan did not change the polyphenol content in the liposomes (86.6%). The uncoated liposomes without grape seed extract were highly prone to lipid oxidation. The cationic chitosan coating, however, improved the oxidative stability to some extent, due to its ability to repel pro-oxidant metals. Encapsulated grape seed extract showed high antioxidant activity in both primary and secondary liposomes, which may be attributed to its polyphenol content. In conclusion, the best chemical stability of liposomes can be achieved using a combination of grape seed extract and chitosan.

  2. Synthesis and Characterization of New Thiolated Chitosan Nanoparticles Obtained by Ionic Gelation Method

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    Reynaldo Esquivel

    2015-01-01

    Full Text Available We derivatized low molecular weight chitosan (LMWC with 3-mercaptopropanoic acid (3-MPA by a coupling reaction. The chemical modification of LMWC was characterized by Fourier transform infrared spectroscopy (FT-IR and nuclear magnetic resonance, 1HNMR. We researched the influence of 3-MPA on the nanoparticles formation by ionic gelation method using sodium tripolyphosphate (TPP as cross-linker reagent. In order to optimize the nanoparticles formation, we studied the effect of the pH solution and molar ratio on nanoparticles stability. Analyses of particle size, morphology, and surface charge were determined by dynamic light scattering, Atomic Force Microscopy, and zeta potential, respectively. It was found that formation of semispherical and stable nanoparticles was improved due to the chemical modification of chitosan. Optimized semispherical nanoparticles of thiolated chitosan were synthesized with the parameters (pH 4.7, molar ratios 1 : 106. Additionally, we reported the thermodynamic profile of the nanoparticles formation determined by isothermal titration calorimetry (ITC. The aggregation process achieved to form nanoparticles of thiolated and nonmodified chitosan consisted of two stages, considering one binding site model. Gibbs free energy (ΔG and binding constant (Ka describe the aggregation process of thiolated chitosan/TPP, which is an initial reaction and followed by an endothermic stage. These results are promising for the possible application of these nanoparticles as nanocarriers and delivery systems.

  3. Preparation of Nanocellulose Reinforced Chitosan Films, Cross-Linked by Adipic Acid

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    Pouria Falamarzpour

    2017-02-01

    Full Text Available Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was performed at 80–100 °C as verified by Fourier transform infrared (FT-IR. The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured, chemically cross-linked (cured, and uncross-linked (prepared by acetic acid films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials.

  4. Evaluation of anisotropic chitosan hydrogels using analytical Mueller matrix method and scanned laser pico-projector.

    Science.gov (United States)

    Huang, Chih-Ling; Chuang, Chin-Ho; Lo, Yu-Lung

    2013-07-25

    Chitosan has excellent biodegradable, biocompatible and bio-absorbable properties and has been found increasing use in the biomedical field in recent decades. The linear birefringence (LB), linear diattenuation (LD), circular birefringence (CB), circular diattenuation (CD), and depolarization properties of chitosan hydrogel films crosslinked in citrate acid buffer solution (CBS) are extracted using an analytical Mueller matrix method. It is shown that the optical phase retardance property of the hydrogel films provides a reliable indication of both the chitosan concentration of the film and the pH value of the CBS crosslinking environment. In addition, chitosan hydrogel suspension with low-concentration crosslinked in CBS environments with various pH values are studied by the speckle contrast of the projected images obtained when illuminating the suspension with a scanned laser pico-projector (SLPP). It is found that for the samples crosslinked in an acidic environment, the speckle contrast decreases with an increasing pH value. By contrast, for the samples crosslinked in an alkaline CBS environment, the speckle contrast increases as the pH value increases. It is concluded that both the phase retardance and the speckle contrast enable the pH value of the CBS crosslinking solution to be reliably determined. However, of the two methods, the SLPP method yields improved measurement sensitivity. Overall, the results presented in this study show that the analytical Mueller matrix method and SLPP method provide an effective means of characterizing the optical properties, concentration and crosslinking environment of chitosan hydrogel films and suspensions.

  5. Preparation and properties of novel hydrogel based on chitosan modified by poly(amidoamine) dendrimer.

    Science.gov (United States)

    He, Guanghua; Zhu, Chao; Ye, Shengyang; Cai, Weiquan; Yin, Yihua; Zheng, Hua; Yi, Ying

    2016-10-01

    Currently, chitosan (CTS) or chitosan derivatives hydrogels are applied in different fields, such as biological materials, medical materials and hygiene materials. In this study, novel chitosan hydrogels were successfully prepared by chitosan and poly(amidoamine) (PAMAM) dendrimer with glutaraldehyde serving as a cross-linking agent. Fourier transform infrared spectroscopy (FTIR), (1)H nuclear magnetic resonance ((1)H NMR) and gel permeation chromatography (GPC) were performed to characterize PAMAM. The structure and morphology of hydrogels were characterized by FTIR, thermo gravimetry analysis (TGA), and scanning electron microscopy (SEM). The swelling properties of the hydrogels were investigated in solutions of pH 1.0 and 7.4. The hydrogels showed good swelling capacities and pH-sensitive swelling properties. Besides, the antibacterial activities of the hydrogels against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were tested by optical density. Compared with the pure chitosan hydrogel, their antibacterial activities were significantly improved with the increase in the blending ratio of PAMAM. And with the increase in cross-linking agent and concentration of CTS, the antibacterial activities increased firstly and then slightly decreased. The hydrogel was expected to be a novel antibacterial material.

  6. Behavior of MC3T3-E1 Osteoblast Cultured on Chitosan Modified with Polyvinylpyrrolidone

    Institute of Scientific and Technical Information of China (English)

    XI Jing; GAO Yuan; KONG Lijun; GONG Yandao; ZHAO Nanming; ZHANG Xiufang

    2005-01-01

    The physical and chemical properties of four kinds of modified chitosan materials made by blending chitosan with polyvinylpyrrolidone (PVP) were investigated. All four of these modified chitosan materials were hydrophilic with water contact angles ranging from 59° to 69°. Fourier transform-infrared spectra of the modified materials showed a new band at 1288 cm-1, implying formation of a surface physical interpenetrating network structure. Enzyme linked immunosorbent assay results indicated that much less fibronectin was adsorbed on the modified materials than on only chitosan. The viability of MC3T3-E1 osteoblasts cultured on the materials was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl- 2H-tetrazolium bromide assay. The results show that adding PVP10000 into the chitosan promotes adhesion of MC3T3-E1 osteoblasts on the modified materials, but has no effect on cell growth and proliferation; while adding PVP40000 reduces cell adhesion, growth, and proliferation. The results suggest that the increased hydrophilicity of the material surface does not always improve its biocompatibility, which will influence the selection and design of biomaterials.

  7. Effects of the protective, curative, and eradicative applications of chitosan against Penicillium expansum in apples.

    Science.gov (United States)

    Darolt, Josiane Cecília; Rocha Neto, Argus Cezar da; Di Piero, Robson Marcelo

    Apple is one of the most important temperate fruit to Brazil economy, and the use of synthetic chemicals has been the main method for reducing postharvest diseases, such as the blue mold, caused by Penicillium expansum. This work intends to evaluate the practical utilization of chitosan for blue mold control. For this purpose, fruits were treated in a preventive and curative way, immersing the fruits in chitosan solution (5 or 10mgmL(-1)), or adding a single drop of this solution (10mgmL(-1)) directly into the injuries. The eradicative effect of the polysaccharide was also evaluated in vitro and in vivo. Chitosan did not show a curative effect against the blue mold, and its eradicative effect was only evidenced on the higher concentration (10mgmL(-1)). On the other hand, preventively, without the addition of adjuvants, chitosan reduced blue mold incidence in fruits by 24% and 93%, through the immersion or the single drop methods, respectively. Thus, it was found that, for long scale utilization, some improvements in the physico-chemical properties of the chitosan are needed, since it was only capable to prevent the infection by P. expansum when directly added on the fruit injury.

  8. Effects of the protective, curative, and eradicative applications of chitosan against Penicillium expansum in apples

    Directory of Open Access Journals (Sweden)

    Josiane Cecília Darolt

    Full Text Available Abstract Apple is one of the most important temperate fruit to Brazil economy, and the use of synthetic chemicals has been the main method for reducing postharvest diseases, such as the blue mold, caused by Penicillium expansum. This work intends to evaluate the practical utilization of chitosan for blue mold control. For this purpose, fruits were treated in a preventive and curative way, immersing the fruits in chitosan solution (5 or 10 mg mL-1, or adding a single drop of this solution (10 mg mL-1 directly into the injuries. The eradicative effect of the polysaccharide was also evaluated in vitro and in vivo. Chitosan did not show a curative effect against the blue mold, and its eradicative effect was only evidenced on the higher concentration (10 mg mL-1. On the other hand, preventively, without the addition of adjuvants, chitosan reduced blue mold incidence in fruits by 24% and 93%, through the immersion or the single drop methods, respectively. Thus, it was found that, for long scale utilization, some improvements in the physico-chemical properties of the chitosan are needed, since it was only capable to prevent the infection by P. expansum when directly added on the fruit injury.

  9. Maize endophytic bacteria as mineral phosphate solubilizers.

    Science.gov (United States)

    de Abreu, C S; Figueiredo, J E F; Oliveira, C A; Dos Santos, V L; Gomes, E A; Ribeiro, V P; Barros, B A; Lana, U G P; Marriel, I E

    2017-02-16

    In the present study, we demonstrated the in vitro activity of endophytic phosphate-solubilizing bacteria (PSB). Fifty-five endophytic PSB that were isolated from sap, leaves, and roots of maize were tested for their ability to solubilize tricalcium phosphate and produce organic acid. Partial sequencing of the 16S rRNA-encoding gene showed that the isolates were from the genus Bacillus and different species of Enterobacteriaceae. The phosphate solubilization index on solid medium and phosphate solubilization in liquid medium varied significantly among the isolates. There was a statistically significant difference (P ≤ 0.05) for both, the values of phosphate-solubilizing activity and pH of the growth medium, among the isolates. Pearson correlation was statistically significant (P ≤ 0.05) between P-solubilization and pH (R = -0.38), and between the gluconic acid production and the lowering of the pH of the liquid medium at 6 (R = 0.28) and 9 days (R = 0.39). Gluconic acid production was prevalent in all the PSB studied, and Bacillus species were most efficient in solubilizing phosphate. This is the first report on the characterization of bacterial endophytes from maize and their use as potential biofertilizers. In addition, this may provide an alternative strategy for improving the phosphorus acquisition efficiency of crop plants in tropical soils.

  10. Heritable site-specific mutagenesis using TALENs in maize.

    Science.gov (United States)

    Char, Si Nian; Unger-Wallace, Erica; Frame, Bronwyn; Briggs, Sarah A; Main, Marcy; Spalding, Martin H; Vollbrecht, Erik; Wang, Kan; Yang, Bing

    2015-09-01

    Transcription activator-like effector nuclease (TALEN) technology has been utilized widely for targeted gene mutagenesis, especially for gene inactivation, in many organisms, including agriculturally important plants such as rice, wheat, tomato and barley. This report describes application of this technology to generate heritable genome modifications in maize. TALENs were employed to generate stable, heritable mutations at the maize glossy2 (gl2) locus. Transgenic lines containing mono- or di-allelic mutations were obtained from the maize genotype Hi-II at a frequency of about 10% (nine mutated events in 91 transgenic events). In addition, three of the novel alleles were tested for function in progeny seedlings, where they were able to confer the glossy phenotype. In a majority of the events, the integrated TALEN T-DNA segregated independently from the new loss of function alleles, producing mutated null-segregant progeny in T1 generation. Our results demonstrate that TALENs are an effective tool for genome mutagenesis in maize, empowering the discovery of gene function and the development of trait improvement.

  11. Variability of factors that affect availability of iron, manganese and zinc in maize lines

    Directory of Open Access Journals (Sweden)

    Dragičević Vesna

    2013-01-01

    Full Text Available Deficiencies of some mineral elements are causing serious health problems, which could be prevented by increase of mineral nutrients in food with supplementation, food fortification or plant breeding. From this point, experiment with 78 maize inbred lines was set up to determine maize lines with improved contents of Fe, Zn and Mn, as well as their relations with phytic acid, inorganic phosphorus and β-carotene, as factors which affect their absorption. Obtained results suggest that investigated maize lines show high variability in concentration of Fe, Mn and Zn, as well as phytic acid (which sustain availability of mineral elements and β-carotene (which enables better absorption of mineral element and minimize negative effect of phytic acid. From this point of view, group of genotypes with phytic P ≤ 3 g kg-1 was interesting. Among them, L2 and L23 are maize lines with relatively high inorganic P, Fe and Zn contents, and together with relatively low ratio between phytic and inorganic P, they could be used as a good source of P, Fe and Zn. On the other hand, L1 and L4 are also maize lines with high inorganic P, β-carotene and Mn, and favourable ratio between phytic acid and Fe and Zn, what could give them advance as source of Mn in breeding programs. The same maize lines could also be candidates with improved ability for Fe and Zn absorption, what is based on high β-carotene content. Maize line L14, with relatively high concentration of all three. [Projekat Ministarstva nauke Republike Srbije, br. TR 31068: Improving the quality of maize and soybean by conventional and molecular breeding

  12. IMMOBILIZATION OF PAPAIN ON CHITOSAN

    OpenAIRE

    Cahyaningrum, Sari Edi; Narsito, Narsito; Santoso, Sri Juari; Agustini, Rudiana

    2010-01-01

    In this study, papain was immobilized on chitosan with Mg(II) cosslinked agent. Studies on free and immobilized papain systems for determination of optimum pH, optimum temperatur, thermal stability and reusability were carried out. The results showed that free papain had optimum pH 6.5 and optimum temperature 55 °C while the immobile papain hadoptimum pH 8 and optimum temperature 80 °C. The thermal stability of the immobilized papain, relative to that of the free papain, was markedly increase...

  13. Chitosan Conduit for Peripheral Nerve Regeneration

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Chitosan, the N-deacetylated form of chitin, has good biocompatibility and biodegradability.This paper investigates the feasibility of using chitosan conduits for peripheral nerve regeneration.Cell culture experiments were used to test the material's cytotoxicity and affinity to nerve cells.Conduit implantation experiments were used to study the degradation of the material and the regeneration of injured sciatic nerves.The primary results indicate that chitosan has good mechanical properties, biocompatibility, and biodegradability and it may be a promising biomaterial for peripheral nerve regeneration.

  14. Chitosan-Pectin Synergistic Interaction and Gelation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Mixed gels of chitosan-pectin were prepared by varying the ratio of constituents in the presence of NaCl. Mixed gel at 3% of total polysaccharide concentration with addtion of 12% NaCl showed a synergistic maximum when the ratio of chitosan to pectin was 60 : 40. The effect of the polysaccharide concentration,the preparation temperature(Tp), the time of incubation, balk salt concentration, the molecular weight and the degree of deacetylation of chitosan on gelation have been studied. Interaction mechanism between molecules of both polysaccharides was investigated by FT-IR spectrometry.

  15. Electrospun antibacterial chitosan-based fibers.

    Science.gov (United States)

    Ignatova, Milena; Manolova, Nevena; Rashkov, Iliya

    2013-07-01

    Chitosan is non-toxic, biocompatible, and biodegradable polysaccharide from renewable resources, known to have inherent antibacterial activity, which is mainly due to its polycationic nature. The combining of all assets of chitosan and its derivatives with the unique properties of electrospun nanofibrous materials is a powerful strategy to prepare new materials that can find variety of biomedical applications. In this article the most recent studies on different approaches for preparation of antibacterial fibrous materials from chitosan and its derivatives such as electrospinning, coating, and electrospinning-electrospraying, loading of drugs or bioactive nanoparticles are summarized.

  16. Morphological, Mechanical and Thermal Study of ZnO Nanoparticle Reinforced Chitosan Based Transparent Biocomposite Films

    Science.gov (United States)

    Das, Kunal; Maiti, Sonakshi; Liu, Dagang

    2014-04-01

    Chitosan based biocomposite transparent films reinforced with zinc oxide (ZnO) nanoparticles at different loading i.e. 2, 4 and 6 wt% were successfully prepared by solution casting method. Shape, size and geometry of the zinc oxide nanoparticles were characterized by scanning electron microscopy (SEM). The biocomposite films were subjected to mechanical characterization, thermal analysis, morphology study and moisture uptake behaviour. The characterization tools used here include wide angle X-ray diffraction study, scanning electron microscopic analysis, differential scanning calorimetric analysis and also UV-visible transmittance behavior. SEM micrographs revealed uniformly dispersed ZnO nanoparticles in biocomposite films. Improvement of the tensile strength about 133 % was observed significantly in case of 4 wt% loaded chitosan/ZnO films with respect to the neat chitosan film. 43 % higher transparency was observed in case of 2 wt% ZnO loaded biocomposites films, thus indicating the best combination of properties of 2 wt% ZnO loaded biocomposite films.

  17. Inhibition of Listeria monocytogenes in Fresh Cheese Using Chitosan-Grafted Lactic Acid Packaging

    Directory of Open Access Journals (Sweden)

    Laura N. Sandoval

    2016-04-01

    Full Text Available A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging.

  18. Inhibition of Listeria monocytogenes in Fresh Cheese Using Chitosan-Grafted Lactic Acid Packaging.

    Science.gov (United States)

    Sandoval, Laura N; López, Monserrat; Montes-Díaz, Elizabeth; Espadín, Andres; Tecante, Alberto; Gimeno, Miquel; Shirai, Keiko

    2016-01-01

    A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA) in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH) losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging.

  19. Predictive analysis of chitosan-based nanocomposite biopolymers elastic properties at nano- and microscale.

    Science.gov (United States)

    Kossovich, Elena L; Safonov, Roman A

    2016-04-01

    Chitosan nanocomposites mechanical properties play a major role in usage of such materials for specific areas of application, mostly in medicine and development of ecologically-friendly production. Computer-based predictive modelling of such composites will reduce costs of their development. In this paper, a multiscale approach for structural characterization and evaluation of mechanical properties is proposed based on hybrid coarse-grained/all atom molecular dynamics. Chitosan films and fibers are constructed and studied in silico as well as chitosan composites with different types of randomly distributed reinforcing fillers (graphene nanoparticles, graphene oxide nanoparticles, carbon nanotubes, chitin nanoparticles). Young's moduli are found for such composites, degrees of improvement of mechanical properties and size effects within the framework of proposed methodology are discussed.

  20. Effect of silanization on chitosan porous scaffolds for peripheral nerve regeneration.

    Science.gov (United States)

    Li, Guicai; Zhang, Luzhong; Wang, Caiping; Zhao, Xueying; Zhu, Changlai; Zheng, Yanhong; Wang, Yaling; Zhao, Yahong; Yang, Yumin

    2014-01-30

    The aim of this study was to evaluate the feasibility of using 3-aminopropyltriethoxysilane (APTE) silanization treatment for modification and biocompatibility of lyophilized chitosan porous scaffolds. The process is beneficial for biomaterial development due to its low toxicity and simplicity. The silanization treatment with low APTE concentration showed no significant influence on the morphology of chitosan scaffolds, while a skin-like surface was observed for the silanized scaffolds treated with high APTE concentration. The porosity and surface amino densities were increased after silanization whereas the swelling ratio was reduced, and the degradation ratio in PBS and anti-acid degradation properties of the silanized chitosan scaffolds were significantly improved. The in vitro Schwann cells culture demonstrated that the silanized scaffolds with 8% APTE could obviously facilitate the attachment and proliferation of Schwann cells, indicating great potential for the application in peripheral nerve regeneration.

  1. Chitosan and Its Derivatives Applied in Harvesting Microalgae for Biodiesel Production: An Outlook

    Directory of Open Access Journals (Sweden)

    Guanyi Chen

    2014-01-01

    Full Text Available Although oil-accumulating microalgae are a promising feedstock for biodiesel production, large-scale biodiesel production is not yet economically feasible. As harvesting accounts for an important part of total production cost, mass production of microalgae biodiesel requires an efficient low-energy harvesting strategy so as to make biodiesel production economically attractive. Chitosan has emerged as a favorable flocculating agent in harvesting of microalgae. The aim of this paper is to review current research on the application of chitosan and chitosan-derived materials for harvesting microalgae. This offers a starting point for future studies able to invalidate, confirm, or complete the actual findings and to improve knowledge in this field.

  2. Chitosan-Assisted Crystallization and Film Forming of Perovskite Crystals through Biomineralization.

    Science.gov (United States)

    Yang, Yang; Sun, Chen; Yip, Hin-Lap; Sun, Runcang; Wang, Xiaohui

    2016-03-18

    Biomimetic mineralization is a powerful approach for the synthesis of advanced composite materials with hierarchical organization and controlled structure. Herein, chitosan was introduced into a perovskite precursor solution as a biopolymer additive to control the crystallization and to improve the morphology and film-forming properties of a perovskite film by way of biomineralization. The biopolymer additive was able to control the size and morphology of the perovskite crystals and helped to form smooth films. The mechanism of chitosan-mediated nucleation and growth of the perovskite crystals was explored. As a possible application, the chitosan-perovskite composite film was introduced into a planar heterojunction solar cell and increased power conversion efficiency relative to that observed for the pristine perovskite film was achieved. The biomimetic mineralization method proposed in this study provides an alternative way of preparing perovskite crystals with well-controlled morphology and properties and extends the applications of perovskite crystals in photoelectronic fields, including planar-heterojunction solar cells.

  3. Effect of crosslinking in chitosan/aloe vera-based membranes for biomedical applications.

    Science.gov (United States)

    Silva, S S; Caridade, S G; Mano, J F; Reis, R L

    2013-10-15

    The positive interaction between polysaccharides with active phytochemicals found in medicinal plants may represent a strategy to create active wound dressing materials useful for skin repair. In the present work, blended membranes composed of chitosan (Cht) and aloe vera gel were prepared through the solvent casting, and were crosslinked with genipin to improve their properties. Topography, swelling, wettability, mechanical properties and in vitro cellular response of the membranes were investigated. With the incorporation of aloe vera gel into chitosan solution, the developed chitosan/aloe-based membranes displayed increased roughness and wettability; while the genipin crosslinking promoted the formation of stiffer membranes in comparison to those of the non-modified membranes. Moreover, in vitro cell culture studies evidenced that the L929 cells have high cell viability, confirmed by MTS test and calcein-AM staining. The findings suggested that both blend compositions and crosslinking affected the physico-chemical properties and cellular behavior of the developed membranes.

  4. Blood compatibility of polyethersulfone membrane by blending a sulfated derivative of chitosan.

    Science.gov (United States)

    Xue, Jimin; Zhao, Weifeng; Nie, Shengqiang; Sun, Shudong; Zhao, Changsheng

    2013-06-01

    In this study, a novel sulfated derivative of chitosan, which could be dissolved in many common organic solvents, is conveniently synthesized for the modification of polyethersulfone (PES) membrane. Elemental analysis, FTIR, (1)H NMR and X-ray diffraction diagrams (XRD) are used to demonstrate the introduction of functional groups. Owing to the solubility in organic solvents, the sulfated derivative of chitosan could be directly blended with PES in organic solvent to prepare membrane by means of a liquid-liquid phase separation technique. The modified membrane showed lower protein (bovine serum albumin (BSA) and bovine serum fibrinogen (BFG)) adsorption and suppressed platelet adhesion. Moreover, the activated partial thromboplastin time (APTT) for the modified membrane was enhanced as high as 60% compared to pure PES membrane. The lower protein adsorption, suppressed platelet adhesion and increased APTT confirmed that the blood compatibility of the modified PES membrane by the sulfated derivative of chitosan was significantly improved.

  5. Chitosan-Based Zwitterionic Polyelectrolytes and Their N-Phosphobetainates: Facile Synthesis and Aqueous Solution Behaviors

    Institute of Scientific and Technical Information of China (English)

    Hongmei Kang; Yuanli Cai; Haijia Zhang; Junjie Deng; Pengsheng Liu

    2005-01-01

    @@ 1Introduction Chitosan has remarkable potential applications in pharmaceutical and cosmetic formulations[1], e.g. for drug delivery systems, tissue engineering, transplant and cell regeneration due to its excellent biocompatibility, biodegradability, mucoadhesion, etc. Its major drawback as considered for pharmaceutical and cosmetic formulations is its poor solubility due to strong hydrogen bonding and compact structures. Considerable efforts were focused on improving its solubility and enforcing its functionality[1]. As well-known that phosphorylcholine (PC), the structural component of cell membrane, is an amphiphile containing the zwitterionic quaternary ammonium and phosphonic acid moieties (phosphobetaine groups). There has been an intensive effort over the past decades to prepare and explore potential applications of the synthetic PC-polymers[2].In this paper, we describe a facile synthesis of chitosan derivatives containing zwitterionic secondary/tertiary amine and phosphonic acid groups and their further N-phosphobetainates. The polyelectrolyte effect and anti-polyelectrolyte effect of the chitosan-based zwitterionic polyelectrolytes were studied.

  6. Oxidation-mediated chitosan as additives for creation of chitosan aerogels with diverse three-dimensional interconnected skeletons

    Science.gov (United States)

    Zhang, Sizhao; Feng, Jian; Feng, Junzong; Jiang, Yonggang

    2017-02-01

    Naturally occurring polymer-based aerogels have myriad practical utilizations due to environmentally benign and fruitful resources. However, engineering morphology-controllable biomass aerogels still represents a great challenge. Here we present a facile solution to synthesize chitosan aerogels having distinguished textures by reacting oxidized chitosan with formaldehyde and chitosan sol. In more detail, chitosan was chemically oxidized using two types of oxidation agents such as ammonium persulphate (SPD) and sodium periodate (APS) to obtain corresponding oxidized chitosan, subsequently cross-linked with chitosan solution containing formaldehyde to harvest SPD-oxidized chitosan aerogels (SCAs) and APS-SPD-oxidized ones (ASCAs) after aging, solvent exchange and supercritical drying processes. We found that the morphologies of as-prepared chitosan aerogels are strongly dependent upon the oxidation pattern towards chitosan. The structural textures of SCAs and ASCAs appear nanoflake-like and nanofiber-like structures, which may be related to spatial freedom of active groups located in chitosan. Selected area electron diffraction analysis reveals that the crystalline properties of chitosan aerogels generally appear the serious deterioration comparing to raw chitosan owing to their interconnected skeletal structure formation. The occurrence of characteristic groups displays cross-linked chain construction by using chemical state measurements such as FT-IR and XPS. Further, a plausible mechanism for controlling morphology of chitosan aerogels is also established. This new family of method for creation of chitosan aerogels may open up a perspective for biomass aerogels with controllable textures.

  7. ZEA MAIZE: A MODERN CRAZE

    Directory of Open Access Journals (Sweden)

    Dhamija Isha

    2013-06-01

    Full Text Available Zea stands for ‘sustaining life’ and Mays stands for ‘life giver’. Zea mays is one of the oldest and most dynamic crop species, which has gained popularity in modern world too, due to its applications in diverse dishes. Corn is produced in every continent of the world with the exception of Antarctica. It is an annual monoecious sunny plant, surviving perfectly in nutrient rich, well-drained soil. Each and every part of the corn, from husk to corn silk is beneficial for the society. There are more than 3,500 different uses for corn products. Corn does much more than feed people and livestock. The plant contains alkaloids, flavonoids, saponins, maizenic acid, vitamins B1, K and minerals like potassium, phosphorous and zinc. Traditionally, Maize is used as an analgesic, anti-diarrheal, anti-prostatitic, anti-lithiasis, anti-tumor, anti-hypertensive, anti-diabetic, anti-hyperlipidemic, anti-inflammatory and anti-oxidant. In this review article, we have narrated miscellaneous uses of corn varieties and described the pharmacological activities, phytoconstituents, nutritional value and traditional uses of maize. The maize has assorted uses like culinary, medicinal and industrial. Corn dishes like corn-meal, corn-flakes, popcorn, “makki ki roti” and corn soup highlight its dominance all over the world. Therefore, maize has become a craze among modern youth.

  8. Some features of irradiated chitosan and its biological effect

    Energy Technology Data Exchange (ETDEWEB)

    Hai, Le; Hien, Nguyen Quoc; Luan, Le Quang; Hanh, Truong Thi; Man, Nguyen Tan; Ha, Pham Thi Le; Thuy, Tran Thi [Nuclear Research Institute, VAEC, Dalat (Viet Nam); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Preparation of chitosan oligomer by radiation degradation was carried out on the gamma Co-60 source. The radiation degradation yield (G{sub d}) of the chitosan was found to be of 1.03. The oligochitosan with 50% of dp>8 fraction was obtained by irradiating the 10% (w/v) chitosan solution in 5% acetic acid at 45 kGy for the chitosan having the initial viscometric average molecular weight, Mv=60,000. Irradiated chitosan showed higher antifungal effect than that of unirradiated one. Furthermore, the irradiated chitosan