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The aim of this paper is the preparation and characterization of cellulose/chitin blend filaments over the experimental blend ratio scope i.e., 2.89 and 6.46% (w/w) chitin content through high wet modulus (HWM) procedure. The spinnability of the invested solutions was found to vary in the following order: chitin < cellulose < 9.5:0.5 blend < 9:1 blend < 8:2 blend < 5:5 blend (9:1 means the mass ratio of cellulose to chitin, so does 9.5:0.5, 8:2, and 5:5). The cross‐section of the blend filaments is of chrysanthemum shape. It was shown through the SEM photographs that there existed grooves on the surface of filaments, which became coarse with increase in chitin content. Based on the data from X‐ray, sonic velocity, intensity, and hygroscopicity, it is concluded that the degree of crystallinity, dry and wet intensity modulus, degree of orientation, and regain rate of the filaments decreased with increase in chitin content in the experiment scope. The mechanical properties of the blend filaments are much higher than those of Crabyon fiber and normal viscose filaments, which proves that the HWM method is an efficient way of preparing cellulose/chitin blend filaments with satisfactory mechanical properties and processing property. The blend filaments prepared have an effective biostatic effect on Staphylococcus aureus, Escherchia coli, and Corinebaterium michiganence according to different testing standards. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Yaima Henry García Orlando Reyes Zamora Rosalba Troncoso-Rojas Martín Ernesto Tiznado-Hernndez María Elena Bez-Flores Elizabeth Carvajal-Millan Agustín Rascn-Chu 《Molecules (Basel, Switzerland)》2021,26(21)
Large volumes of fruit and vegetable production are lost during postharvest handling due to attacks by necrotrophic fungi. One of the promising alternatives proposed for the control of postharvest diseases is the induction of natural defense responses, which can be activated by recognizing molecules present in pathogens, such as chitin. Chitin is one of the most important components of the fungal cell wall and is recognized through plant membrane receptors. These receptors belong to the receptor-like kinase (RLK) family, which possesses a transmembrane domain and/or receptor-like protein (RLP) that requires binding to another RLK receptor to recognize chitin. In addition, these receptors have extracellular LysM motifs that participate in the perception of chitin oligosaccharides. These receptors have been widely studied in Arabidopsis thaliana (A. thaliana) and Oryza sativa (O. sativa); however, it is not clear how the molecular recognition and plant defense mechanisms of chitin oligosaccharides occur in other plant species or fruits. This review includes recent findings on the molecular recognition of chitin oligosaccharides and how they activate defense mechanisms in plants. In addition, we highlight some of the current advances in chitin perception in horticultural crops. 相似文献
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Shigehiro Hirano Min Zhang Hideki Yamane Yoshiharu Kimura Kojiro Matsukawa Masuo Nakagawa 《Macromolecular bioscience》2003,3(10):620-628
The mono‐filaments (> 10 m in length) of chitosan and the blends of chitosan‐collagen, chitin‐collagen and chitin‐silk fibroin were wet‐spun. The mono‐filaments were chemically N‐modified with each of n‐fatty acid anhydrides, intra‐molecular carboxylic anhydrides, fragrant aldehydes and transition metal ions. The mono‐filament was aligned on a straight line with the mono‐filament of silk fibroin or poly(ethylene terephthalate) (PET), and a bundle of one to three mono‐filaments was coated with a medium of sericin (Se), chitosan or N‐acylchitosan to give rise to novel silk‐mimic filament composites. The filaments coated with a medium of sericin exhibited 26–27 denier for the titer, 2.46–3.36 gf · denier?1 for the tenacity and 11.8–25.0% for the elongation. The apparent density (denier · μm?1 in the filament diameter) of the filament composites was about 3–4 times higher than that of the mono‐filaments. Portion of fragrant aldehydes in Schiff's base was slowly hydrolyzed at room temperature by contacting with atmospheric moisture in the open air, and released from the fragrant filaments and composites. The filament composites coated with a chitosan medium were thrombogenic, and those coated with N‐acylchitosans were antithrombogenic.
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Díaz-Rojas EI Argüelles-Monal WM Higuera-Ciapara I Hernández J Lizardi-Mendoza J Goycoolea FM 《Macromolecular bioscience》2006,6(5):340-347
Accurate determination of chitin and protein contents in crustacean biomass and the intermediate products during the industrial isolation of chitin cannot be made directly from the total nitrogen content, unless the appropriate corrections are applied. This method, however, is affected by the presence of other nitrogen-containing chemical species that are formed endogenously or by the action of microorganisms during the handling of the sample. Therefore, an alternative rapid method to estimate the contents of these components can be very useful both in research and in various fields of application. An original method has been developed to address this problem. The method consists of the development of a set of equations based on the stoichiometric contents of nitrogen of chitin and protein whereby the amounts of each component can be estimated from the value of the total nitrogen content, provided the rest of the proximate composition of the sample is accurately known. In order to validate the procedure, a set of model mixtures of pure chitin and protein concentrate in the solid state, both extracted from shrimp head waste, are used. Excellent agreement between the predicted and real values of chitin and protein are obtained (R2=0.98, slope=0.90). When the proposed method is tested in the analysis of real samples obtained from five different processing protocols of pretreatment of raw shrimp head, it is found that in general the values of protein and chitin contents throughout the various stages of the process vary as expected. [GRAPH: SEE TEXT] Variation of the measured total nitrogen versus calculated stoichiometric total nitrogen of the chitin-protein mixtures. 相似文献
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Diethylaminoethyl–chitin (DEAE–chitin) was synthesized by introducing DEAE groups onto the C(6)–OH in chitin. DEAE–chitin was N-deacetylated by heating in aqueous 10% sodium hydroxide containing sodium borohydride to prepare the diethylaminoethyl–chitosan (DEAE–chitosan). In addition, DEAE–chitin was quaternized with ethyl halide to produce triethylaminoethyl–chitin (TEAE–chitin). Their antibacterial activities were evaluated by using colony count against Staphylococcus aureus and Escherichia coli by means of shake flask method. The antibacterial activity was found to increase in order of DEAE–chitin, DEAE–chitosan, TEAE–chitin. DEAE–chitin was hydrolyzed by enzymes to investigate the effect of molecular weight on its antibacterial activities. The antibacterial activity was dependent on the structure, particularly on the molecular weight of chitin derivatives. © 1997 John Wiley & Sons, Ltd. 相似文献
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Chitin deacetylase can be used in the green and efficient preparation of chitosan from chitin. Herein, a novel chitin deacetylase SbCDA from Streptomyces bacillaris was heterologously expressed and comprehensively characterized. SbDNA exhibits its highest deacetylation activity at 35 °C and pH 8.0. The enzyme activity is enhanced by Mn2+ and prominently inhibited by Zn2+, SDS, and EDTA. SbCDA showed better deacetylation activity on colloidal chitin, (GlcNAc)5, and (GlcNAc)6 than other forms of the substrate. Molecular modification of SbCDA was conducted based on sequence alignment and homology modeling. A mutant SbCDA63G with higher activity and better temperature stability was obtained. The deacetylation activity of SbCDA63G was increased by 133% compared with the original enzyme, and the optimal reaction temperature increased from 35 to 40 °C. The half-life of SbCDA63G at 40 °C is 15 h, which was 5 h longer than that of the original enzyme. The improved characteristics of the chitin deacetylase SbCDA63G make it a potential candidate to industrially produce chitosan from chitin. 相似文献
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Thi Thi Nge Naruhito Hori Akio Takemura Hirokuni Ono Tsunehisa Kimura 《Journal of Polymer Science.Polymer Physics》2003,41(7):711-714
A high magnetic field of 5 T was used to fabricate a magnetically aligned, optically anisotropic, liquid‐crystalline chitin/poly(acrylic acid) composite. The aligned mesophase was fixed by photoinitiated free‐radical polymerization. From an examination of polarized optical micrographs and an X‐ray diffraction study, a high degree of orientation of 0.70 was observed for the composite with a higher liquid‐crystalline chitin concentration (10.70 wt %); the orientation was reduced with a decreased chitin concentration at a given acrylic acid concentration. The X‐ray data for the developed composite showed a uniplanar orientation for the chitin crystallites, with its molecular long axes perpendicular to the direction of the magnetic field. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 711–714, 2003 相似文献
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Poly(epsilon-caprolactone) (PCL)/chitin and PCL/chitosan blend films with compositional gradients were successfully fabricated by a dissolution/diffusion method; that is, repeatedly pouring the PCL/chitin (or PCL/chitosan) blend solutions, with variable composition, onto polysaccharide layers. The compositional gradient structure in the resulting films was characterized by polarized optic microscopy, ATR-FT-IR and trans-FT-IR microscopic spectroscopy. Enzymatic degradability of the PCL/chitin and PCL/chitosan blend films with compositional gradients in the presence of lysozyme was compared with those of homogeneous films and two-layer films. It was found that the degradation rate of PCL/chitin blend films with a compositional gradient was far lower than that of the neat chitin film, whereas the degradation rate of PCL/chitosan blend films with a compositional gradient was close to that of the neat chitosan film. The suppression of the chitosan crystallization, which accelerates the enzymatic degradation, at the surface of PCL/chitosan films with a compositional gradient was much more severe than that for PCL/chitin films with a compositional gradient. 相似文献
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《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):723-732
Water‐soluble chitin (half‐deacetylated chitin) was prepared from chitosan by N‐acetylation with acetic anhydride. Alginate/water‐soluble chitin blend fibers were prepared by spinning their mixture solution through a viscose‐type spinneret into a coagulating bath containing aqueous CaCl2 and ethanol. The structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). structure analysis indicated good miscibility existed between alginate and water‐soluble chitin, due to the strong interaction from the intermolecular hydrogen bonds and electrostatic interactions. Best values for the dry tensile strength and breaking elongation were obtained when the water‐soluble chitin content was 30 wt%. The wet tensile strength and breaking elongation decreased with the increase of water‐soluble chitin content. The introduction of water‐soluble chitin in the blend fiber can improve the water‐retention properties of the blend fiber compared to pure alginate fiber. The fibers treated with aqueous solution of silver nitrate have good antibacterial activity to Staphylococcus aureus. 相似文献
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The alarm is rang for friendly fire; Saccharomyces cerevisiae (S. cerevisiae) newfound as a fungal pathogen with an individual feature. S. cerevisiae has food safety and is not capable of producing infection but, when the host defenses are weakened, there is room for opportunistic S. cerevisiae strains to cause a health issues. Fungal diseases are challenging to treat because, unlike bacteria, the fungal are eukaryotes. Antibiotics only target prokaryotic cells, whereas compounds that kill fungi also harm the mammalian host. Small differences between mammalian and fungal cells regarding genes and proteins sequence and function make finding a drug target more challenging. Recently, Chitin synthase has been considered as a promising target for antifungal drug development as it is absent in mammals. In S. cerevisiae, CHS3, a class IV chitin synthase, produces 90% of the chitin and essential for cell growth. CHS3 from the trans-Golgi network to the plasma membrane requires assembly of the exomer complex (including proteins cargo such as CHS5, CHS6, Bach1, and Arf1). In this work, we performed SELEX (Systematic Evolution of Ligands by EXponential enrichment) as high throughput virtual screening of the RCSB data bank to find an aptamer as potential inhibit of the class IV chitin synthase of S. cerevisiae. Among all the candidates, G-rich VEGF (GVEGF) aptamer (PDB code: 2M53) containing locked sugar parts was observed as potential inhibitor of the assembly of CHS5–CHS6 exomer complex a subsequently block the chitin biosynthesis pathway as an effective anti-fungal. It was suggested from the simulation that an assembly of exomer core should begin CHS5–CHS6, not from CHS5-Bach1. It is notable that secondary structures of CHS6 and Bach1 was observed very similar, but they have only 25% identity at the amino acid sequence that exhibited different features in exomer assembly. 相似文献
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Rangasamy Jayakumar Nitar Nwe Hideaki Nagagama Tetsuya Furuike Hiroshi Tamura 《Macromolecular Symposia》2008,264(1):163-167
Chitin is a polysaccharide found in the outer skeleton of insects, crabs, shrimps, and lobsters and in the internal structures of other invertebrates. Sulfated chitin was prepared by reacting carboxymethyl chitin (CM-chitin) with 2-aminoethane sulfonic acid by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) catalyst. The prepared sulfated chitin was characterized by FTIR, elemental analysis, thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The degree of substitution was found to be 0.98 by elemental analysis. The TGA studies showed that sulfated chitin was less thermal stability than carboxymethyl chitin. This is due to the grafting reaction. The sulfated chitin membranes were prepared from sulfated chitin and then crosslink with glutaradehyde. The biodegradation process was performed in PBS (pH 7.4) containing lysozyme (10 µg/ml) at 37 °C in an incubator. Experimental results from weight loss throughout the study showed that the biospecific degradation occur on the membrane by lysozyme. 相似文献
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Physicochemical characterization of α‐chitin, β‐chitin,and γ‐chitin separated from natural resources
Mi‐Kyeong Jang Byeong‐Gi Kong Young‐Il Jeong Chang Hyung Lee Jae‐Woon Nah 《Journal of polymer science. Part A, Polymer chemistry》2004,42(14):3423-3432
We isolated α‐chitin, β‐chitin, and γ‐chitin from natural resources by a chemical method to investigate the crystalline structure of chitin. Its characteristics were identified with Fourier transform infrared (FTIR) and solid‐state cross‐polarization/magic‐angle‐spinning (CP–MAS) 13C NMR spectrophotometers. The average molecular weights of α‐chitin, β‐chitin, and γ‐chitin, calculated with the relative viscosity, were about 701, 612, and 524 kDa, respectively. In the FTIR spectra, α‐chitin, β‐chitin, and γ‐chitin showed a doublet, a singlet, and a semidoublet at the amide I band, respectively. The solid‐state CP–MAS 13C NMR spectra revealed that α‐chitin was sharply resolved around 73 and 75 ppm and that β‐chitin had a singlet around 74 ppm. For γ‐chitin, two signals appeared around 73 and 75 ppm. From the X‐ray diffraction results, α‐chitin was observed to have four crystalline reflections at 9.6, 19.6, 21.1, and 23.7 by the crystalline structure. Also, β‐chitin was observed to have two crystalline reflections at 9.1 and 20.3 by the crystalline structure. γ‐Chitin, having an antiparallel and parallel structure, was similar in its X‐ray diffraction patterns to α‐chitin. The exothermic peaks of α‐chitin, β‐chitin, and γ‐chitin appeared at 330, 230, and 310, respectively. The thermal decomposition activation energies of α‐chitin, β‐chitin, and γ‐chitin, calculated by thermogravimetric analysis, were 60.56, 58.16, and 59.26 kJ mol?1, respectively. With the Arrhenius law, ln β was plotted against the reciprocal of the maximum decomposition temperature as a straight line; there was a large slope for large activation energies and a small slope for small activation energies. α‐Chitin with high activation energies was very temperature‐sensitive; β‐Chitin with low activation energies was relatively temperature‐insensitive. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3423–3432, 2004 相似文献
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N. D. Burkhanova S. M. Yugai Kh. P. Pulatova G. V. Nikononvich R. Yu. Milusheva N. L. Voropaeva S. Sh. Rashidova 《Chemistry of Natural Compounds》2000,36(4):352-355
The structure of crab chitin and chitosan from it with various degrees of deacetylation (DDA) are studied by x-ray diffraction, IR spectroscopy, and microscopy. Deacetylation causes substantial destruction of the chitin crystal structure, makes it amorphous, increases the defectiveness of crystallites as the DDA increases, weakens intermolecular H-bonds, and eliminates the fibrillarity. 相似文献
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Highly Biocompatible Nanofibrous Microspheres Self‐Assembled from Chitin in NaOH/Urea Aqueous Solution as Cell Carriers 下载免费PDF全文
Bo Duan Xing Zheng Zhixiong Xia Xiaoli Fan Lin Guo Prof. Jianfeng Liu Prof. Yanfeng Wang Prof. Qifa Ye Prof. Lina Zhang 《Angewandte Chemie (International ed. in English)》2015,54(17):5152-5156
In this work, chitin microspheres (NCM) having a nanofibrous architecture were constructed using a “bottom‐up” fabrication pathway. The chitin chains rapidly self‐assembled into nanofibers in NaOH/urea aqueous solution by a thermally induced method and subsequently formed weaved microspheres. The diameter of the chitin nanofibers and the size of the NCM were tunable by controlling the temperature and the processing parameters to be in the range from 26 to 55 nm and 3 to 130 μm, respectively. As a result of the nanofibrous surface and the inherent biocompatibility of chitin, cells could adhere to the chitin microspheres and showed a high attachment efficiency, indicating the great potential of the NCM for 3D cell microcarriers. 相似文献
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Quantitative in vitro biopolymerization to chitin in native chitosomal membranes supported by silica microparticles 总被引:1,自引:0,他引:1
To investigate the unknown physical mechanisms of chitin biosynthesis quantitatively, we designed a quantitative in vitro biopolymerization assay by deposition of native chitosomal membranes from Saccharomyces cerevisiae onto solid silica microparticles of a defined size (? = 3 microm). The homogeneous coating of particle surfaces with native chitosomal membranes observed by confocal microscopy agrees well with the surface coverage calculated by the phosphate analysis. The amount of the synthesized chitin polymers is determined by radioactive assays, which demonstrate that chitin synthase in particle-supported membranes retains its specific enzymatic activity. In comparison to planar substrates, particle supports of defined size (and thus surface area) enable us to amplify the signals from immobilized proteins owing to the much larger surface area and to the capability of concentrating the sample to any given sample volume. Moreover, the large density of particle supports offers unique advantages over purified chitosomes in the quick separation of particle-supported membranes and materials in bulk within 1 min. This allows for the termination of the polymerization reaction without the disruption of the whole membranes, and thus the chitin polymers released in bulk can quantitatively be extracted. The obtained results demonstrate that the native biological membranes on particle supports can be utilized as a new in vitro biopolymerization assay to study the function of transmembrane enzyme complexes. 相似文献
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Douglas R. Lyon Jr. Bryan R. Smith Noureddine Abidi Julia L. Shamshina 《Molecules (Basel, Switzerland)》2022,27(13)
The isolation of chitin utilizing ionic liquid 1-ethyl-3-methylimidazolium acetate has been determined to result in polymer contaminated with proteins. For the first time, the proteins in chitin extracted with ionic liquid have been quantified; the protein content was found to vary from 1.3 to 1.9% of the total weight. These proteins were identified and include allergenic proteins such as tropomyosin. In order to avoid ‘traditional’ hydroxide-based deproteinization of chitin, which could reduce the molecular weight of the final product, alternative deproteinization strategies were attempted. Testing of the previously reported deproteinization method using aqueous K3PO4 resulted in protein reduction by factors varying from 2 to 10, but resulted in significant phosphate salt contamination of the final product. Contrarily, the incorporation of GRAS (Generally Recognized as Safe) compound Polysorbate 80 into the polymer washing step provided the polymer of comparable purity with no contaminants. This study presents new options for the deproteinization of chitin that can replace traditional approaches with methods that are environmentally friendly and can produce high purity polymer. 相似文献